Practical Applications of Medical Geology 3030538923, 9783030538927

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Malcolm Siegel · Olle Selinus Robert Finkelman Editors

Practical Applications of Medical Geology

Practical Applications of Medical Geology

Malcolm Siegel  •  Olle Selinus Robert Finkelman Editors

Practical Applications of Medical Geology

Editors Malcolm Siegel Department of Internal Medicine University of New Mexico LJS Consulting Sandia Park, New Mexico Albuquerque, NM, USA

Olle Selinus Linnaeus University Kalmar, Sweden

Robert Finkelman Department of Geosciences The University of Texas at Dallas Richardson, TX, USA

ISBN 978-3-030-53892-7    ISBN 978-3-030-53893-4 (eBook) https://doi.org/10.1007/978-3-030-53893-4 © Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Preface

What Is Practical Medical Geology? Medical Geology has been defined as: The impacts of geologic materials and geologic processes on animal and human health (Selinus et al. 2005). During the past 20 years, some 15 books on medical geology have been published (see Table 26.2 in Chap. 26 this volume). For the most part, these books describe the health impacts of various elements, minerals, organic compounds, volcanic eruptions, dust, etc., as well as regional distribution of medical geology issues and tools and techniques used in medical geology. This book attempts to place medical geology in a broader societal and educational context by demonstrating practical applications of the field and by providing guidance to those wishing to make contributions in this field. To do so, we must first examine the structure of a medical geology investigation and then provide the tools needed to carry out the study. Medical geology provides a holistic structure for integrating information drawn from the geological and medical sciences. It provides a systematic approach to connect the presence of contaminants in the environment to human health effects. Practical medical geology studies can be related to well-accepted principles in risk assessment and risk management. The uncertainties in each subdiscipline of medical geology limit the precision of risk assessment estimates, and these must be considered in developing a useful risk management strategy. Because effective risk management must consider the costs, benefits, and unintended consequences of a proposed intervention, the integrative nature of medical geology provides a useful framework for policy makers dealing with the environmental and public health problems related to exposures to natural materials and to the byproducts of resource extraction activities such as mining. In order to provide guidance to new practitioners of medical geology, we must address several basic questions. How does one become a medical geologist? What knowledge does one need to become a medical geologist? How should one go about determining if there is a legitimate medical geology issue? More specifically, we v

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ask important questions such as: what public health information should a geoscientist need to know to identify possible medical geology issues? What terms should a geoscientist be familiar with to communicate with public health and medical professionals? How much geology and mineralogy do a public health researcher need to understand the impacts of the natural environment on human health, and what terms do they need to know to clearly communicate with the geoscience community? Medical geology differs from other branches of geology in an important way: the results of a medical geology investigation can have a direct impact on the health of a human population. An important role of medical geology is to bridge the “cultural” differences between the way that geoscience specialists and medical specialists might view risks posed by geologic materials and processes. The psychometric model of risk analysis posits that perception of acceptable risk is impacted by two independent factors—the “dread risk” factor and the “unknown risk” factor. The dread risk factor is important when the risk is uncontrollable, fatal, catastrophic, and fatal and increases over time. The “unknown risk” factor is also important for risk elements that are not observable to the exposed population, unfamiliar, or have delayed effects. By providing accessible information on both the environmental behavior and health effects of potentially hazardous geogenic materials, medical geology can reduce the dread and unknown risk factors and lead to more effective risk communication and risk management.

Sectional Plan Part I of the book provides a framework, based on principles of risk assessment and performance assessment, that can be used to guide a study of the effects of contaminant releases on human health. This comprehensive approach allows for the description and quantification of the effects of hydrogeochemical and biomedical processes that will control how rapidly a geogenic contaminant can disperse into the environment and then impact the health of an exposed population. The third chapter delves more deeply into the concepts of risk assessment presented in the first two chapters of the book and describes the societal origins of the concept of risk, its evolution, and the institutions that deal with it in a modern industrial society. The second part of the book describes specific tools, based on the geosciences and the biomedical sciences, that can be used in a risk-based analysis. These include laboratory studies of metal and actinide speciation in solid and liquids, methods to evaluate potential population exposures to contaminants, biokinetic models of the transformation of toxins within humans and molecular techniques in epidemiology. The third part of the book provides examples of medical geology studies that incorporate the tools described in Part II of the book. It offers topical and regional case studies dealing with the health impacts of soils, radioactive materials, coal, and trace elements as well as overviews on clay therapy, balneotherapy, urban medical

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geology, occupational health issues, water quality impacts on indigenous peoples, and veterinary geology. The third part offers an overview of medical geology literature and examples of a successful educational outreach initiative and a successful outreach effort to engage other disciplines and decision-makers.

Uses and Audience for the Book This book is a complement to the book Essentials of Medical Geology. Medical geology is not the exclusive domain of geoscientists. Public health researchers, medical researchers, chemists, geographers, environmental scientists, physical anthropologists, and others are all engaged in various aspects of medical geology. The intention of this book is to bring these various disciplines together, so that they can have common ground on which to communicate better and collaborate more effectively. Furthermore, it is our intention that this book will prove to be useful to the professionals in all of these fields as well as graduate students working on medical geology issues and undergraduates curious about this exciting and satisfying field of research. Albuquerque, NM, USA Kalmar, Sweden  Richardson, TX, USA 

Malcolm Siegel Olle Selinus Robert Finkelman

Acknowledgments

Production of this book required the assistance of many colleagues and friends. Each chapter was reviewed by at least two independent professionals with backgrounds in a variety of fields that span the scope of this work. We are indebted to the following reviewers: Maria Albin Eric Brevik Jose Centeno Siobhan Cox Alecos Demetriades Ron Fuge Michael Greenberg Elizabeth Herndon Andrew Hursthouse Georg Krücken G. Thomas Lavanchy Martin McBriarty Andrew Nelson Mark Pelizza Illa Pillalamarri Mohamed Nabil Shaikh Giedrė Taletavičienė Michael Watts Ted Wilton

Val Richard Beasley Thomas Brikowski Lewis Cook Christine Davidson Gabriela Dogaru Reto Giere Jordán Győző Eshani Hettiarachchi Alan Jacobs Anna Ladenberger William Lyons Jennifer McGuire D. Kirk Nordstrom Paulo Alexandre da Silva Pereira Robert H. Poppenga Magnus Svartengren Denisa Vutchkova Håkan Westberg Deniz Sanliyuksel Yucel

Johanna Blake Charles Bryan Jose Manuel Cerrato Corrales Vanessa De La Rosa Jane Entwhistle Kerri Clough Gorr Travis Hedwig Jackie Horn Allan Kolker Art Langer Mark Maddaloni Constantin Munteanu Imasiku Nyambe Timothy D. Phillips Paul Schuster Ross Taggart Brandon Warrick Lynda Williams

Work on this book took over 2 years, and during that time, the editors relied on the patience and support of their families and friends to keep us sane and on track. The last 3 months of preparation of the book occurred during the COVID-19 pandemic. While we were safely practicing social distancing, front-line workers in the hospitals, stores, and essential services were keeping our society functioning. We are grateful for their service. ix

Contents

Part I Medical Geology and Risk Assessment 1 A Framework for Applied Medical Geology: Part I. The Environmental Pathways Analysis��������������������������������������    3 Malcolm Siegel 2 A Framework for Applied Medical Geology: Part II. The Biological Impact Analysis ������������������������������������������������   51 Malcolm Siegel 3 Assessing and Accepting Risk: Interdisciplinary Perspectives������������  113 Frank Hirtz Part II Methods in Practical Medical Geology 4 Techniques for Assessing Metal Mobility in the Environment: A Geochemical Perspective ��������������������������������������������������������������������  139 Sumant Avasarala 5 Investigating the Quantity and Form of Heavy Metal Contaminants for Improved Risk Analysis and Mitigation ����������������  169 Michael S. Massey 6 A Transdisciplinary Approach for Studying Uranium Mobility, Exposure, and Human Health Impacts on Tribal Lands in the Southwest United States����������������������������������������������������������������  193 Joseph H. Hoover, Alicia M. Bolt, Scott W. Burchiel, José M. Cerrato, Erica J. Dashner-Titus, Esther Erdei, Jorge Gonzalez Estrella, Eliane El Hayek, Laurie G. Hudson, Li Luo, Debra MacKenzie, Sebastian Medina, Jodi R. Schilz, Carmen A. Velasco, Katherine Zychowski, and Johnnye L. Lewis

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7 GIS, Geostatistics, and Machine Learning in Medical Geology����������  215 Chaosheng Zhang, Renguang Zuo, Yihui Xiong, Xun Shi, and Conan Donnelly 8 Application of Bioavailability Measurements in Medical Geology ����  235 Mark Cave and Joanna Wragg 9 Relating Environmental Lead and Arsenic Exposure to Observed Levels in Humans ��������������������������������������������������������������  263 Teresa S. Bowers 10 Application of Biomedical Molecular Techniques in Environmental Sciences����������������������������������������������������������������������  287 Salina Torres, Yvonne Dailey, and Kirsten White 11 Medical Diagnosis for Geoscientists ������������������������������������������������������  319 Leah Nelson, Cody Saxton, and Naomi Ty Asha Nichols Part III Topics and Case Studies in Medical Geology 12 Medical Geology of Soil Ecology������������������������������������������������������������  343 Lily Pereg, Joshua J. Steffan, Csongor Gedeon, Phil Thomas, and Eric C. Brevik 13 Sources and Health Impacts of Chronic Exposure to Naturally Occurring Radioactive Material of Geologic Origins��������������������������  403 Dustin May and Michael K. Schultz 14 Coal Combustion Residuals and Health������������������������������������������������  429 Julia Kravchenko and Laura S. Ruhl 15 Environmental Contamination from Uranium Mining and Milling in the Western U.S.��������������������������������������������������������������  475 Bruce Thomson 16 Health Effects of Exposure to Specific Geologic Materials: Summary of Clinical Findings, Treatment, and Prevention����������������  525 Naomi Ty Asha Nichols and Leah Nelson 17 Sources, Pathways, and Health Effects of Iodine in the Environment����������������������������������������������������������������������������������  565 Olufunke Mary Sanyaolu, Hassina Mouri, Olle Selinus, and Abiodun Odukoya 18 Naturally Occurring Arsenic and Boron in Geothermal Systems and Their Health Effects: A Case Study from Turkey��������������������������  615 Alper Baba, Yasar Kemal Recepoglu, and Hamidreza Yazdani

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19 A Review on the Occurrence of Some Potentially Harmful Elements in the Natural Environment and Their Health Implications: Examples of Fluoride, Iron and Salinity in the South-Eastern Kenya Region�������������������������������������������������������������������������������������������  637 Patrick Kirita Gevera, Mark Cave, Kim Dowling, Peter Gikuma-­Njuru, and Hassina Mouri 20 Antibacterial Clays: Scientific Investigations of Their Practical Applications in Medicine ������������������������������������������������������������������������  671 Lynda B. Williams 21 Balneotherapy: An Overview of Healing with Natural Waters ����������  697 K’tso Nghargbu 22 Exploring the Intersections of Environmental Health and Urban Medical Geology ������������������������������������������������������������������  721 Gabriel Filippelli and Robert B. Finkelman 23 Occupational Health and Medical Geology������������������������������������������  749 Robert Wålinder 24 Issues Related to Water Affecting Indigenous Peoples of North America��������������������������������������������������������������������������������������  769 Anita L. Moore-Nall 25 Veterinary Geology����������������������������������������������������������������������������������  833 Jan Myburgh, Kelly McGowan, and Anthony Davis Part IV Medical Geology in Policy and Education 26 A Guide to the Medical Geology Literature������������������������������������������  855 Olle Selinus, Robert B. Finkelman, Naomi Ty Asha Nichols, and Kreg Walvoord 27 Medical Geology in Africa: An Example of a Successful Educational and Research Initiative at the University of Johannesburg, South Africa ��������������������������������������������������������������  865 Hassina Mouri 28 Medical Geology Outreach: A Major Success Story from Turkey������  883 Alper Baba and Robert B. Finkelman Glossary������������������������������������������������������������������������������������������������������������  895 Index������������������������������������������������������������������������������������������������������������������  907

Part I

Medical Geology and Risk Assessment Malcolm Siegel

Introduction The chapters in the first part of the book present a structure for applied medical geology investigations. The first two chapters describe a risk-based framework: the environmental pathways and biological impact analysis. This structure provides a systematic progression of analyses describing the release of a contaminant, dispersion into the environment, exposure of populations, and resulting health effects. This model presents two heuristics, i.e., simplifying frameworks to find an intermediate or short-term solution to complex problems through loosely defined rules. The problem here is the assessment of health risks posed by environmental hazards, and the solutions obtained are not guaranteed to be the optimal final solution but instead are sufficient for screening purposes in risk management. Chapter 1 describes the environmental pathways analysis. This includes the experimental and computational tools used to describe the release of a contaminant into the environment, and its subsequent transport and transformation by hydrogeochemical processes that lead to exposure by humans or animals. This defines the heuristic of geoavailability, which is the amount of a contaminant that could reach a potentially exposed population. Chapter 2 discusses the Biological Impact Analysis, which describes how the exposure impacts the health of the population. This analysis includes the tools of exposure assessment and toxicology. These methods are used to estimate the second heuristic, bioavailability, which is the fraction of an ingested toxin that would reach the biological site of damage.

M. Siegel Department of Internal Medicine, University of New Mexico, School of Medicine, Albuquerque, NM, USA LJS Consulting, Sandia Park, NM, USA

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The heuristic of geoavailability captures the complex processes involved in environmental transport. Thus, if the geoavailability of a contaminant is very low in site-specific conditions, then it is reasonable to propose that the environmental risk is relatively low, and exposure is not significant. If the bioavailability is low under specific conditions, then it is likewise reasonable to propose that the health risk due to the exposure is low.

Fig. 1  From Siegel (2021, this volume)

Medical geology differs from other branches of geology in an important way: the results of a medical geology investigation can be used to directly evaluate risks to the health of a human population. Differing interpretations of the significance of a medical geology investigation may have two types of sources. First, there may be data and model ambiguity that can lead to different interpretations of the results of the scientific study. Second, the interpretation of the importance of the results may differ due to normative ambiguity, i.e., a difference in the definition of acceptable risk. Chapter 3 examines the sociological dimensions of risk assessment. This chapter describes the origins of the concept of risk, its evolution, and the institutions that deal with it in a modern industrial society. In addition to the quantitative “hard science” studies that are described in many chapters of this book, this chapter describes the roles that normative, cultural, and societal influences have on what we consider to be “acceptable” risk. This is an important question that determines which risks we try to avoid, which risks we accept, and how we direct our resources to mitigate different kinds of risks.

Chapter 1

A Framework for Applied Medical Geology: Part I. The Environmental Pathways Analysis Malcolm Siegel

Abstract  Medical Geology provides a holistic framework to analyze the potential health effects from exposures to natural materials and to the environmental impacts of mineral resource development and chemical and nuclear waste disposal. The Environmental Pathways/Biological Impact Analysis comprises a systematic progression of analyses starting with a potential release of a contaminant into the environment, leading to population exposures and resulting health effects. This chapter describes the first part of the analyses, the Environmental Pathways Analysis, which produces an estimate of the amount of a pollutant that could reach a potentially exposed population. Typically, the amount of a pollutant that is available to affect the health of humans is less than the amount released from the source. This reduction of the amount and mobility of the contaminant in the geosphere is associated with a number of abiotic and biotic processes in the environment and is related to its geoavailability as discussed in this chapter. Different compartments within the Environmental Pathways Analysis involve many different disciplines in the physical, chemical, geological, and environmental sciences. The methods include materials analysis, laboratory studies, and theoretical predictions of the speciation and solubility of contaminants based on principles of chemical thermodynamics and kinetics, hydrogeologic modeling and field measurements, remote sensing, and spatial analysis. Analysis of the geoavailability of a contaminant provides realistic estimates of the potential exposure resulting from releases from pollutant sources. This chapter summarizes the basic concepts that underlie geoavailability and identifies key references to aid the reader in applying them to practical Medical Geology applications. Keywords  Risk assessment · Geoavailability · Contaminant transport · Contaminant source · Solubility · Dissolution rate · Waste form · Reactive transport models · Chemical speciation models · Spectroscopic methods · Sorption · Colloids · Retardation factor · Environmental sampling and monitoring · Geostatistics M. Siegel (*) Department of Internal Medicine, School of Medicine, University of New Mexico, Albuquerque, NM, USA LJS Consulting, Sandia Park, NM, USA © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_1

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1.1  I ntroduction: The Need for Medical Geology in Risk Assessment Medical Geology is the quintessential multidisciplinary science. It provides a holistic framework for integrating information drawn from the geological and medical sciences. It illustrates the different methods and underlying paradigms of these sciences and provides an opportunity to address the significance of the uncertainties inherent in each of the disciplines in a comprehensive analysis. The form of a complete medical geology analysis can be related to well-accepted principles in Risk Assessment and Risk Management. In the realm of Risk Assessment, medical geologists must deal with the extrapolations that underlie both the medical and geological sciences. For example, predictions of environmental transport of contaminants that lead to exposures of populations must rely on inferences drawn from simple laboratory studies and field studies of complex systems. Similarly, assessments of potential health effects often rely on in vitro or in vivo studies of simple systems or epidemiological studies of complex populations. The uncertainties in each discipline that limit the precision of risk estimates must be considered in developing a useful Risk Management strategy. Because effective Risk Management must consider the costs, benefits, and unintended consequences of a proposed intervention, the integrative nature of Medical Geology provides a useful framework for policy makers dealing with the environmental and public health problems related to common exposures to natural materials and to the byproducts of resource extraction activities such as mining. The purpose of this and the next chapter is to describe the Environmental Pathways/Biological Impact Analysis, a tool within Medical Geology, which provides a holistic approach to risk assessment and management. It provides a systematic progression of analyses describing the release of a contaminant, dispersion into the environment, exposure of populations, and resulting health effects. This chapter describes the first part of the evaluation, the Environmental Pathways Analysis, which produces an estimate of the amount of a contaminant that could reach a potentially exposed population. Chapter 2 discusses the Biological Impact Analysis, which describes how the exposure impacts the health of the population. These two chapters provide a high-level summary of the techniques used in these analyses. More details about the techniques and case studies for such practical medical geology analyses are described in subsequent chapters in this book and referenced works.

1.1.1  M  edical Geology and Public Perceptions of Environmental Health Risks Potential hazards from the environment are one of the most discussed topics in modern society. The environmental damage that human activities has caused in the geosphere and biosphere has led both professional scientists and popular science

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writers to claim that humans are causing the sixth extinction event in earth history (Kolbert 2014; Ceballos et  al. 2017). On the local scale, historical and potential releases of toxic substances by industrial activities have a major effect on economic activity and regulations. The risks from such activities are not borne equitably; while prosperous nations and neighborhoods enjoy the benefits of risk mitigation and avoidance, poorer segments of society in the developed and underdeveloped sectors of the world are often subject to hazardous exposures and practices. Emotional protests against proposed mining activities or waste disposal projects are common even when many years and dollars have been spent in risk assessment. The opposition to siting waste disposal facilities near communities has been termed a “NIMBY” or “not in my backyard” strategy by environmental groups such as Sierra Club and NRDC (Freudenberg 1984; Werbach 1997). For example,  efforts to use solution-mining techniques known as in situ leaching or recovery for uranium extraction in the Southwest and other parts of the country have met with public opposition at the local and national level (see for example (Democracy Now! 2010; Hanaček 2019). Proponents of in situ uranium mining maintain that no adverse environmental or health effects have been observed, whereas opponents claim that surrounding populations have experienced devastating health effects (see Box 1.1). Similarly, many years of public opposition preceded the opening of the Waste Isolation Pilot Plant in New Mexico, USA, notwithstanding the huge effort made to evaluate the safety of this geologic disposal program (Jenkins-Smith et al. 2009). In addition, despite the expenditure of billions of dollars and efforts by leading scientists for the past 30 years, public opposition to the proposed geological repository for nuclear waste at Yucca Mountain, Nevada, has prevented this program from succeeding. Box 1.1 Conflicting Views on Uranium Mining “In over three decades of ISR operations, there have been no significant, adverse impacts to adjacent, non-exempt USDWs outside the recovery zone and into the related area of review (AOR) from ISR uranium recovery operations in the United States.” Testimony of Fletcher Newton, Exec VP Uranium One, Inc. on behalf of National Mining Association to Energy and Natural Resources Committee, US Senate, March 12, 2008. “This is the first time that the NRC has licensed a mining operation in a community drinking water supply, despite the fact that no aquifer in which ISL uranium mining has occurred has ever been restored to pre-­ mining conditions” Indian Country Today: comments on citizen petition against Crownpoint ISR. “Thousands of open mines now sit on land in the Navajo and Great Sioux Nations. They continue to poison the water, land and air causing devastating health effects such as respiratory illnesses, cancers and birth defects.” The Toxic Effects of Uranium Mining on Tribal Lands with Don Yellowman and Charmaine White Face, Clearing the Fog Radio Talk Show 1480 AM. May 23, 2013.

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Successful acceptance of environmental remediation or industrial projects by local communities requires several key elements: (Step 1) community education and involvement at the early stages of the project; (Step 2) transparent analysis and review of the proposed project by all the stakeholders; (Step 3) repeating Step 1 (US Department of Energy 1993; Hightower et al. 2001; Hightower 1995; Kelley et al. 2002). Without comprehensive environmental transport analysis and exposure assessment, identification of a potential source of a contaminant could lead to assumption of an inevitable health effect. Similarly, an observed health effect in a population could be attributed to an unsubstantiated environmental exposure and then to an assumed historic release of a substance without adequate epidemiological or environmental analyses. Medical Geology provides a holistic framework for risk assessment and management. A systematic approach, connecting contaminant releases to human health effects, provides a coherent scientific basis to respond to the concerns of the public. In addition, the tools of Medical Geology provide a framework to differentiate between the effects of anthropogenic sources of toxic materials and natural sources on human health.

1.1.2  Risk Assessment and Risk Management The important distinction between risk assessment and management risk management has long been recognized by regulators and scientists but may be overlooked in public discussion of risk (Fig. 1.1) (USEPA 1999a; Macler 2003). Risk assessment involves (1) identification of a hazard and its description in terms of a dose-­response relationship and (2) in parallel, an assessment of the likelihood and extent of potential

Fig. 1.1  Relationship between risk assessment and risk management modified from frameworks proposed by the National Academy of Sciences and others (National Research Council 1983; Macler 2003). The diagram acknowledges that other factors such as risk perception and the political strategies of stakeholders may influence the regulations and safety measures that are adopted by governments (Clahsen et al. 2018)

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exposures to populations of the hazardous substance. Together, these analyses lead to characterization or assessment of the potential risk to populations. That information is then used to formulate a risk management or mitigation strategy. In addition, other considerations are included in the risk management strategy. These include the technical challenges to mitigating the risk, any legal constraints that might prevent application of technical methods and the economic costs of implementing the management approach. There may be social and cultural constraints that also must be considered in the implementation. These analyses are important because often, the unintended consequences of risk management measures have been seen to be more important than the original risk that was being managed (Hamilton and Viscusi 1999). The original description of the risk assessment/risk management process (Risk Assessment Paradigm) has since been modified by the National Research Council (1996, 2009) to include other elements such the importance of public perception of risk and the normative values of risk assessors, risk managers, and stakeholders. Clahsen et al. (2018) analyze eight different conceptual frameworks for the assessment of environmental risks and describe the importance of psychological and cultural influences, public communication, advocacy, and the roles of many different stakeholders. In Chap. 3 of this book, Hirtz (2021) discusses the evolution of risk assessment in a broader sociological framework and addresses the concept of “acceptable” risk. Performance assessment of proposed nuclear waste repositories is an example of the risk assessment/management process (Siegel et  al. 1983). This evaluation includes qualitative analyses of potential scenarios and their associated probabilities, and the quantification of the potential releases, environmental transport, population exposures, and associated health effects that could be related to the performance of the proposed nuclear waste repository. The designs of geologic repositories for both commercial waste and transuranic nuclear wastes were based in part on performance assessment calculations (Rechard 1995a, b; Yardley et al. 2016; Siegel et al. 1983). Elements of this approach are incorporated into the methodology described in this chapter (see Box 1.2). The experimental techniques, computational methods, and case studies presented in this chapter and other chapters in this book provide examples of the approaches that can be used in both risk assessment and risk management for practical medical geology problems. Box 1.2 Performance Assessment (PA) Terms Repository Source (term): Properties of the waste that is emplaced in a engineered containment system. The rate of contaminant release from the source is referred to as the “source term” in PA calculations. It may be encased in an engineered barrier. Repository Near-Field: Part of the repository system that envelops the source and whose chemical and physical properties reflect the interaction between properties of the source and the surrounding environment. Repository Far-Field: The environment outside of the near field whose properties are dominated by the pre-emplacement natural environment.

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1.2  Environmental Pathways and Biological Impact Analysis A systematic description of the processes and qualities that lead from releases of a pollutant into the environment and resultant human health effects is summarized in an Environmental Pathways/Biological Impact Analysis (Fig.  1.2). This model is similar in structure to the performance assessment models described earlier and also to models proposed by Ott (1985), Lioy (1995), and Lambert (personal communication, 1996). The component parts are: • Discharge or release of contaminant from a source—this can be a point source or nonpoint source and can be natural or anthropogenic in origin; • Transport of the contaminant in the environment as influenced by hydrobiogeochemical processes such as advection, dispersion, and chemical and biological reactions; • Resultant pattern of pollutant presence in the environment, which can be characterized by several monitoring, analytical, and computational methods; • Population exposures, which are determined by both environmental processes as well as activity patterns of the population; • A biological dose resulting from the external exposure and determined by metabolic processes; • Health effects from the biological dose and influenced by other factors such as health status, diet, and genetics, which determine the responsiveness of an individual to the dose.

1.2.1  Geoavailability and Bioavailability The first part of this model, the Environmental Pathways Analysis, describes the amount of a potential contaminant that is available to affect the health of humans; this may be much less than the amount released from the source. This reduction is associated with a number of abiotic and biotic processes in the environment and is related to its geoavailability as is discussed later in this chapter. The second part of

Fig. 1.2  Environmental pathways/biological impact analysis allows compartmentalization of risk analysis and risk management

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the analysis, the Biological Impact Analysis, describes the phenomena that affect the toxicity of the contaminant in contact with a human receptor in the exposed population, i.e. affecting its bioaccessibility and bioavailability. These are determined by both the chemical and mineralogical properties of the ingested contaminant as well as metabolic processes that occur in the body as discussed in the next chapter. The interface between these two analyses is exposure assessment. This analysis incorporates elements of several of the units in Fig.  1.2; different techniques can be used to infer, estimate, or measure external and internal exposures to geomaterials as discussed in the next chapter.

1.2.2  A  queous Environmental Pathways Analysis and Geoavailability Some of the scientific disciplines that may be involved in the aqueous Environmental Pathways Analysis are illustrated in Fig.  1.3. Examples, current modeling, and experimental approaches are described in more detail in the following sections. The emphasis in this chapter is on contaminants that are released and transported in groundwater. Some of the same phenomena may also be important when considering contaminants present in surface waters, soils, or transported as dusts and aerosols, but these involve other analyses as discussed in other chapters of this book. The source of the contaminant may be chemical or radioactive waste in solid or liquid form (often referred to as the “waste form” or “source term” in quantitative performance assessment analyses).

Fig. 1.3  Different compartments within the environmental pathways analysis involve many different disciplines in the physical, chemical, geological, and environmental sciences when describing the transport of contaminants in groundwater

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1.2.2.1  Discharge or Release of Contaminant from a Source Types of Sources and Waste Forms A Medical Geology risk analysis begins with characterization of the source of a contaminant. The amount of the potential contaminant as well as its physical and chemical form must be considered. Sources may be highly localized or dispersed nonpoint sources; they may anthropogenic or natural in origin. Anthropogenic sources may be the result of poorly planned disposal of chemical or radioactive wastes, related to failures of engineered barriers, or the result of small releases of toxic or radioactive substances over long periods of time and over widespread areas. Examples of the localized anthropogenic sources include the routine disposal of wastes from nuclear weapons productions during the Cold War at facilities such as the Hanford Reservation in Washington State, and Oak Ridge National Laboratory in Tennessee (US Department of Energy 1997), and widespread contamination at multiple sites in the former Soviet Union and Eastern Europe (Cochran et al. 1993; Slezak 1997; Shutov et al. 2002). Examples of the barrier failures include releases of metals from the Gold King Mine in Colorado (Chief et al. 2016), failures of dams holding back wastes from uranium milling operations in New Mexico (Weimer et al. 1981; Abdelouas 2006), or coal ash disposal in Tennessee (Ruhl et al. 2009). Examples of regional nonpoint sources include releases of metals or other toxic compounds produced by small-scale artisanal mining operations, cottage industries, urban stormwaters, and agricultural practices (Barrett 2000; McCarthy and Capel 2009; Dubrovsky and Hamilton 2010; Ping et al. 2012; Cobbina et al. 2013; Bradley and Worland 2015; Gozzard et al. 2011). Characterization of Contaminant Release from Sources

The release of contaminant from a source may be characterized by field studies or by predictive calculations in the course of performance assessment of planned chemical or nuclear waste repositories. The release of the pollutant into the environment may be controlled by the properties of the waste form and by natural and engineered barriers. Both experimental and computational studies are used to obtain an estimate of the likely barrier efficiency over time. Barriers for nuclear waste include steel or metal alloy containers and backfills composed of sorbent or reductive materials. The projected performance of these barriers is based on combinations

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of probabilistic calculations of failure rates and deterministic rates of processes such as dissolution, diffusion, and stress corrosion cracking (Rechard 1995a, b; Chu et al. 1983). Such sources are often referred as the “near-field” of the waste repository (see Box 1.2) For high-volume, low-level radioactive and chemical wastes, engineered barriers may include lined disposal ponds that have sensors to detect any leakage (Bonaparte et  al. 2008; Caldwell 1992; ITRC 2003; Daniel and Koerner 2007). Whatever the origin, characterization of an existing source or predicting the performance of a potential source involves a number of different scientific disciplines, including materials analysis, analytical chemistry, geochemistry, fluid mechanics, geology, mineralogy, and hydrology. Sources may evolve over time as chemical and physical processes alter the initially deposited, often highly reactive materials. For example, the changes in uranium mill tailings over time are described by Abdelouas and coworkers (Abdelouas et al. 1998; Abdelouas 2006). In some cases, such as the collapse of an impoundment dam containing coal ash wastes or slurries from mining operations, the release of the contaminant into the environment will be sudden, catastrophic, and dominated by physical transport. In other cases, the release may be slow, over extended periods of time as the waste form dissolves in groundwater and its constituents are carried into the environment outside of the boundaries of the contaminant source or waste deposit. Conceptual Models for Thermodynamic and Kinetic Controls on Dissolution The concentrations of contaminants within the source and released into the environment will be limited by both solubility limits and adsorption. However, within the source, solubility limits are often more important than sorption processes (although exceptions to this may be found especially if an adsorptive barrier such as clay or zeolites are included in the barrier engineering; in addition, solubility may limit the concentrations in the far field). However, because concentrations of contaminants will usually be highest at the source, comments about solubility studies will be made here and comments about sorption processes will be found in Sect. 1.2.2.3, which deals with the “far field” of the system. Thermodynamic Controls on Solubility The dissolution of the waste will be controlled by a number of physical processes and chemical parameters. These include the properties of the waste form such as its chemical composition and specific surface area as well as the rate of groundwater seepage, diffusion rates, groundwater geochemical parameters such as pH, Eh, and ionic strength, and concentrations of specific chemical species that interact with the wastes. These reflect both the specific mechanisms involved in dissolution as well as the thermodynamic stability of the waste. The thermodynamic stability of a solid inorganic chemical waste can be characterized by its mineral saturation index (SI), which is commonly expressed as:

SI  log  Q / K  ,

(1.1)

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M. Siegel

where Q is the reaction quotient (or ion activity product) and K is the temperature and pressure dependent equilibrium constant of the dissolution reaction. In ideal systems, when the saturation index of the waste form exceeds 1, then the solid will not dissolve; if the SI is less than 1, then the solid will dissolve. However in natural systems in which biological process are important, other behaviors might be observed. Kinetic Controls on Dissolution The dissolution rate of a waste may be dependent on a combination of physical and chemical properties. Several conceptual models are presented now; this section is not meant to be a comprehensive summary of this subject but rather to describe some of the models currently used. A general, simple kinetic model of dissolution, where the dissolution rate, measured as change in solute concentration, C, as a function of time t, is:

dC / dt  k m  C s  C 

m

C  Cs  ,

(1.2)

where the rate of change dC/dt is in units of (g cm−3 s1), Cs is the concentration of the solute at saturation with respect to the solid in units of (g cm−3), m is the order of the reaction, and km is the rate constant in units of (gm cm−3)1−m. Here, the rate constant can be related to the thickness of a laminar layer that exists at the surface of the solid and the transport of dissolved material through the layer by molecular diffusion (Lerman 1979). In other cases, the rates of dissolution reactions of some minerals and solid wastes are often zeroth order, that is they are independent of the concentrations of the reactants or products. For example, dissolution rate laws for some solid wastes might be zeroth order, similar to those of silica and other silicate minerals (Langmuir 1997). In contrast to these simple models, dissolution rates are often dependent upon the concentrations of a number of reactants and products and can be very dependent upon the pH of the solution. In a closed system, where no additional sources or sinks of this species exist, the reaction rate parameter and the reaction order can be functions of concentration or time, as the reaction mechanism changes and the system progresses from a state of strong under saturation to near saturation. For other wastes, a complex composite rate law may describe the rate of an overall reaction as a sum of rates of the number of constituent elementary reactions. For example, a rate law for calcite dissolution and precipitation is:

R  k1 H    k2 H 2 CO30   k3  H 2 O  -k4 Ca 2   HCO3   .

(1.3)

Here, different terms dominate at different pH values as calcite dissolves in a closed system (Plummer et al. (1979).

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Example: Uranium Dissolution in Mill Tailing and Nuclear Waste Sites The dissolution of uraninite (UO2) has been characterized in support of studies of the formation and solution mining of uranium roll front deposits as well as performance assessment of proposed high-level nuclear waste repositories; it provides an example of the complexities of dissolution processes. Grandstaff (1979) showed that the kinetics of uraninite dissolution in water was a function of the specific surface area, the presence of organic solutes, impurities in the uraninite, dissolved oxygen content of the water, total dissolved carbonate, and temperature. The dissolution rate was affected by the rates of a number of processes at the surface of the solid, which can vary over the course of the dissolution in laboratory experiments. These include the slow diffusion of oxygen through the surface layer, oxidation of the surface layer, and reaction between water and carbonates to create aqueous uranyl carbonate species that interact with the surface of the solid. The interaction of these processes was reflected in rate laws whose orders were dependent on time as well as the pH of the solution in contact with the uraninite. More recently,  Posey-dowty et al. (1987) studied the dissolution rate of uraninite crystals and uranium roll front ore samples over a range of uraninite saturations under environmentally relevant conditions of pH and bicarbonate and oxygen concentrations. They proposed that the following rate law would be relevant for modeling the formation and migration of roll-front ores, solution mining of uranium ores by bicarbonate, and the dispersion of uranium about mining sites and tailings dumps. d U 

dt



kA 1 / 2  U  U    O2   s  , V  Us 

(1.4)

where [U] is the measured molar concentration of uranium in solution, Us is the saturation concentration of uraninite,  A is the total surface area of the uraninite crystals in m2, the rate constant k is 4.9(± 2.2) × 10−5 (mole)(l)(m−2)(atm)−1/2(min)−1, V is the volume of aqueous solvent in liters, (O2) is the partial pressure of oxygen in atmospheres, and t is the time in minutes. The dissolution of uranium from sediment particles contaminated by the uranium mining operations near Church Rock, New Mexico, was examined by deLemos et al. (2008). They found that the dissolution rate was best modeled with a linear form of the parabolic diffusion equation (Sparks 1986), consistent with other studies of the dissolution of uranyl silicates (Liu et al. 2004, 2006). The dissolution rate of biogenic uraninite produced by bioremediation of uranium-contaminated areas was investigated under oxidizing conditions by Ulrich et al. (2009). The use of surface analysis techniques such as X-ray adsorption spectroscopy (XAS) and high-­ resolution X-ray photoelectron spectroscopy (XPS) allowed further elucidation of the mechanisms of uraninite dissolution (see following immediate discussion and in the chapters by Massey (2021) and Avasarala (2021) in this volume for descriptions

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of these techniques.) These studies indicated the role of intermediate U(V) surface species formed by oxidation of U(IV) and adsorbed to the surface. Disproportionation (formation of U(IV) and U(VI)) followed by reaction with carbonate species in solution leads to release of U(V) and U(VI) species from the mineral surface. Under mildly oxidizing conditions, formation of a U(VI) mineral coating may control the dissolution rate. The purpose of this preceding discussion is not to provide a comprehensive review of the studies of dissolution but instead to illustrate the complexity of predictions of the dissolution rates of source terms that may be important for medical geology studies. It is important to recognize that extrapolation from simple laboratory studies to any particular natural system is fraught with many uncertainties. The scope and intent of this chapter necessarily limits the discussion of dissolution to very basic concepts of chemical kinetics. More in-depth treatments are offered by a number of standard textbooks such as Lerman (1979), Sparks (1986), Morel and Hering (1992), and Langmuir (1997) as well as more advanced works such as Lasaga and Kirkpatrick (1981). Experimental Techniques to Study Waste Form Behavior A wide variety of experimental techniques are used in studies of the chemistry of contaminants in various waste forms; a review of this subject is beyond the scope of this chapter. Some general points, relevant to radioactive contamination, are described in Siegel and Bryan (2003, 2014) and are summarized briefly now. Many of these experimental techniques and theoretical calculations can also be applied to other environmental contaminants such as heavy metals. Nitsche (1991) provides a useful general summary of the principles and classic techniques of solubility studies. A large number of techniques have been used to characterize the speciation of radionuclides. These include potentiometric methods, optical absorbance, and vibrational spectroscopy. Extraction techniques to separate oxidation states and complexes are combined with radiometric measurements of various fractions. A series of papers by Choppin and coworkers provides good descriptions of these techniques; see for example Caceci and Choppin (1983) and Schramke et al. (1988). Cleveland and coworkers used a variety of extraction techniques to characterize the speciation of plutonium, neptunium, and americium in natural waters (Cleveland et  al. 1983; Rees et  al. 1983). More recent studies are described by Gorman-Lewis et al. (2008), Morss et al. (2010), and Alessi et al. (2012). A variety of methods have been used to characterize the solubility-limiting radionuclide solids and the nature of sorbed species at the solid/water interface in experimental studies. Electron microscopy and standard x-ray diffraction techniques can be used to identify some of the solids from precipitation experiments. X-ray absorption spectroscopy (XAS) can be used to obtain structural information on solids and is particularly useful for investigating noncrystalline and polymeric actinide compounds that cannot be characterized by X-ray diffraction analysis (Silva and Nitsche 1995). X-ray Absorption Near-Edge Spectroscopy (XANES) can provide information about the oxidation state and the local structure of actinides in

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solution, in solids, or at the solution/solid interface. Many of the surface spectroscopic techniques have been reviewed by Bertsch and Hunter (2001) and Brown Jr et al. (1999) and are discussed by Massey (2021, this volume). Felmy and coworkers have carried out a number of experimental studies of solubility and speciation of plutonium, neptunium, americium, and uranium that illustrate combinations of various solution and spectroscopic techniques (Felmy et al. 1989, 1990; Xia et al. 2001). More recently, Opel et al. (2007) studied the solubility of amorphous and crystalline uranium dioxide by combined spectroscopic methods. Massey (2021) describes these techniques in more detail in this book. Modeling the Aqueous Chemical Behavior of the Waste Components The probable behavior of the contaminants within the waste over time can be estimated using geochemical speciation and reaction path codes such as MINTEQ (Gustafsson 2013), PHREEQC (Parkhurst 2017), and the Geochemist Workbench (Aqueous Solutions LLC 2019) as described in the next section and in Avasarala (2021, in this volume). Extensive chemical databases have been developed for these computer programs and by the USGS, US EPA, US DOE, and many international groups in support of the disposal of hazardous wastes and commercial and low-level nuclear wastes (Nordstrom and Archer 2003; Nuclear Energy Agency 2018). For most solubility and speciation studies, calculations of the activity coefficients of aqueous species are required. For waters with relatively low ionic strength (0.01–0.1 molal), simple corrections such as the Debye Huckel relationships are used (Langmuir 1997). This model accounts for the electrostatic, nonspecific, long-­ range interactions between water and the solutes. At higher ionic strengths, short-­ range interactions must be taken into account. The NEA (Nuclear Energy Agency 2018) has developed a database for ionic strengths up 3.0 molal based on the Specific Interaction Theory (SIT) approach of Bronsted (1922) and Scatchard (1936). The US DOE has used the more complex Pitzer model for calculations of radionuclide speciation and solubility in its Nuclear Waste Management Programs (Siegel and Bryan 2014). In addition to chemical speciation, modeling the release of contaminants from a source requires representing fluid flow and other dynamic effects under isothermal and nonisothermal conditions. Reactive transport models couple chemical speciation calculations to transport equations as described in the next section. 1.2.2.2  Dilution, Reaction, and Transport in the Environment

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Prediction of the fate of contaminants released from a source must consider transport of aqueous species and colloids through the saturated zone, the vadose zone, or the atmosphere. The chemistries of the contaminants and their geochemical environment will control their transport properties by controlling their solubility, speciation, sorption, and transport by particulates. Once released into the environment, contaminants will be exposed to very different geochemical conditions than those that characterize the original source. The mobility and concentrations of contaminants are affected by geochemical parameters such as pH, Eh, the concentrations of inorganic and organic complexing ligands, and the availability of mineral surfaces to which the metal complexes can adsorb (see Fig. 1.4). In most cases, the concentrations of contaminants in the environment along a transport path will be lower than those within the source and the specific chemical forms or speciation of the contaminant will also be different due to these processes. These species concentrations will be governed by both the thermodynamic properties of the constituents of the system as well as the kinetics of the reaction rates among them. All of these factors will impact the geoavailability or the fraction of the contaminant that can come into contact with potentially exposed populations. Important processes that will remove aqueous species of contaminants from the groundwater and decrease its geoavailability are discussed in Sect. 1.3. Basic concepts of the geochemistry of solutes in the environment are summarized in Drever (1982), Morel and Hering (1992), and Langmuir (1997); more detailed descriptions based on recent research can be found in Drever (2014) and Lollar (2014). Descriptions of the geochemistry of radioactive contaminants and metals in the environment are summarized by the USEPA (Ford et al. 2007b; Ford and Wilkin 2010) and Siegel and Bryan (2014). A roadmap for characterization of contaminated field sites has been developed by the USEPA (Ford et al. 2007a) under the program of natural and accelerated natural attenuation. The framework was

Fig. 1.4  Geochemical interactions between a contaminant, groundwater solutes, and geomedia

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developed in order to provide guidance for studies designed to establish whether or not natural attenuation of contaminants transported from source terms would be sufficiently effective to limit potential exposure of populations downstream from contaminated sites. A number of available tools for characterization of important environmental parameters as well as the speciation of contaminants and the identity of solubility controlling solid phases are described in the chapters by Avasarala (2021) and Massey (2021), in this volume. The concentrations and speciation of contaminants in the environment can be measured directly using techniques described later or estimated by theoretical calculations similar to those described for the source term earlier. Principles of low-­ temperature geochemical calculations are summarized in Nordstrom and Campbell (2014). Computer software that can be used to predict the concentrations and speciation of naturally occurring solutes and containants by processes such as hydrolysis and oxidation/reduction include programs such as PHREEQC (Parkhurst 2017) and MINTEQ (Gustafsson 2013) as mentioned previously. Additional references on geochemical modeling include the user’s manuals for these computer codes (Gustafsson 2013; Parkhurst 2017; Aqueous Solutions LLC 2019). Reaction path and reactive transport modeling can be carried out for the “far field” of the environment using computer codes (Cygan et  al. 2006; Steefel et  al. 2015) discussed in more detail below. Many of the experimental techniques to characterize materials described in the previous section on source term are used to provide data used in modeling transport of contaminants in the environment. In addition, the physical and chemical characteristics of the geomedia may be described by geostatistical techniques applied to much larger spatial dimensions as discussed in Sect. 1.2.2.3. Experimental Methods to Characterize Sorption Both solubility and sorption will affect the concentration of contaminants in the far field; solubility studies are discussed in Sect. 1.2.2.1 above. In many cases, concentrations of contaminants in the far field will be below solubility limits, and therefore sorption may be the more important control on transport. Several different approaches have been used to measure sorption of heavy metals and radionuclides by geomedia. These include (1) the laboratory batch method, (2) the laboratory flow-through (column) method, and (3) the in situ field batch sorption method. Batch Sorption Studies Laboratory batch tests are the simplest experiments; they can be used to collect distribution coefficient (Kd1) values or other partitioning coefficients to parameterize sorption and ion exchange models. Descriptions of the batch techniques for  The term sorption is often used to describe a number of surface processes, including adsorption, ion exchange, and coprecipitation that may be included in the calculation of a Kd. For this reason, some geochemists will use the term sorption ratio (Rd) instead of distribution coefficient (Kd) to describe the results of batch sorption experiments. In this chapter, we use Kd to refer to the simple 1

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sorption of metal complexes, anions, and radionuclides onto geomedia and descriptions of calculations used to calculate distribution coefficients can be found in Kent et al. (1988), Jenne (1992), Park et al. (1995), Siegel et al. (1995a), USEPA (1999b), and ASTM (2010). In batch systems, the distribution coefficient or sorption ratio (Kd or Rd) describes the partitioning of a contaminant between the solid and liquid phases. These parameters are commonly measured under equilibrium or at least steady-state conditions unless the goal of the experiment is to examine the kinetics of sorption. It is defined as follows:



Rd  ml / g  

CS , CL

(1.5)

where CS is the concentration of the contaminant on the solid and CL is the concentration in solution. In practice, the concentration of the contaminant on the solid is rarely measured. Rather, it is calculated from the initial and final solution concentrations, and the operative definition for the Kd becomes:



Rd  ml / g  

CiVi  Cf Vf  / m Cf

.



(1.6)

where Ci and Cf are the initial and final concentrations of contaminant in solution, respectively; Vi and Vf are the initial and final solution volumes (ml); and m (g) is the mass of the solid substrate added to the system. Many published Rd data from batch sorption measurements are subject to a number of limitations as described by Siegel and Erickson (1986), Serne and Muller (1987), and by USEPA (1999b, c). These include a solution:solid ratio that is much higher than that present in natural conditions, an inability to account for multiple sorbing species, an inability to measure different adsorption and desorption rates and affinities, and an inability to distinguish between adsorption and coprecipitation. The Rd may also be dependent on the concentration of the contaminant in solution in the case of nonlinear isotherm. As shown in Fig. 1.5 below, Kd values are dependent on many geochemical and physical parameters, and it is important to always use Rd values collected under appropriate site-specific conditions. Batch methods are also used to collect data to calculate equilibrium constants for surface complexation models (SCMs). Commonly for these models, sorption is measured as function of pH and the surface charge of the geomedia. The triple layer model (TLM) by Davis and Leckie (1978a, b) is an example of a SCM. These models describe sorption within a framework similar to that used to describe associations between metals and ligands in solutions. Reactions involving surface sites and equilibrium sorption model and Rd to refer to batch sorption data that may include these other nonquantified effects. For practical reasons, even though the Rd values include other processes, they are often treated as Kd values in calculations of contaminant transport.

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Fig. 1.5  Comparison of sorption models

solution species are postulated based on experimental data and theoretical principles. Mass/charge balance and mass action laws are used to predict sorption as a function of solution chemistry. Different SCMs incorporate different assumptions about the nature of the solid-solution interface. These are summarized by Siegel and Bryan (2003), described in detail in many other references (Kent et al. 1988; Davis and Kent 1990; Stumm 1992; Jenne 1992) and illustrated more recently by Payne et al. (2013). A variety of methods have been used to characterize the nature of sorbed species at the solid/water interface in experimental studies. Surface spectroscopy techniques such as Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS) have been used to characterize uranyl and neptunyl complexes sorbed onto oxides/ hydroxides and clays (Combes et  al. 1992; Chisholm-Brause et  al. 1994; Bargar et al. 2000; Duff et al. 2002; Arai et al. 2007). Additional studies are summarized by Massey (2021, in this volume). In Fig. 1.5, several commonly used sorption models are compared with respect to the independent constants that they require. These constants are valid only under certain chemical conditions, and therefore are dependent or conditional with respect to the other chemical variables described in the third column of the figure. Kd is the radionuclide distribution constant; K and n are the Freundlich isotherm parameters; β+ and β−are surface complexation constants for protonation and deprotonation of surface sites; K+, K−, βan, βcat are surface complexation constants for sorption of cations and anions; C, C1, and C2 are capacitances for the electrical double layers; σ, σo, and σb are surface charges at different surface plane; (Me) and (S) are concentrations of sorbing ions and surface sites, M, L are background electrolytes, I is the ionic strength, and Ns and Sa are the site density and specific surface of the substrate, respectively. Models using a Kd require only a single constant but are only valid for a very specific condition, whereas the Triple Layer model requires specification of 8 constants but can be used over a range of conditions. Two main approaches have been used to represent the variability of sorption under natural conditions. These include (1) sampling experimental Rd values from a probability distribution function (pdf), and (2) calculating a Kd using thermodynamic data with surface complexation models (SCMs). Because of the diversity of solutions, minerals, and radionuclides that will be present at contaminated sites and potential repository sites, a large body of empirical radionuclide Rd sorption data has been generated. Isotherm data describing nonlinear sorption and its effect on

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transport have also been collected for many contaminants. Databases of Rd values that can be used to estimate pdfs for various geologic media are summarized by Bayley et  al. (1990), McKinley and Scholtis (1992), Triay et  al. (1993), and the USEPA (1999c). Attempts have been made to find statistical relations between experimental variables and the measured sorption ratios (Rds). Several of these studies were summarized by Mucciardi and Orr (1978), Mucciardi (1978), and Serne and Muller (1987). Approaches to using thermodynamic sorption models to predict or guide the collection of Kd data are summarized by the Nuclear Energy Agency (2001) and Payne et al. (2013). The Rd and isotherm values can be used in commonly used transport models, while thermodynamic sorption models can be used in the more specialized reactive transport models discussed below. Laboratory Column Tests Laboratory column tests are more difficult to perform than batch tests but overcome some of the limitations of batch tests because they take into account dynamic effects due to transport and heterogeneity in the geomedia not seen in batch tests. In these experiments, the concentration of the contaminant in the column effluent is monitored to obtain a breakthrough curve; the shape of the curve provides information about sorption equilibrium and kinetics and other properties of the crushed rock or intact rock column. Transport of contaminants by colloids as discussed here can also be observed in column tests. Proper design, descriptions of experimental procedures, and methods of data interpretation for column tests can be found in Relyea (1982), Torstenfelt (1985), Triay et  al. (1993), Siegel et  al. (1995b), Sims et  al. (1996), Gabriel et al. (1998), and USEPA (1999b). Additional descriptions of column tests can be found in the chapter by Avasarala (2021, in this volume). Measured batch Rdvalues are often used as Kd values to calculate a retardation factor (R), which describes the ratio of the rate of groundwater movement to the rate of contaminant movement:



R  1

Kd  , 

(1.7)

where ρ is the bulk density of the porous medium and Ѳ is the porosity. This equation can be rearranged, and contaminant retardation values measured from column breakthrough curves can be used to calculate Kds. As discussed in a later section, this equation can also be used to obtain a rough approximation of the geoavailability under simple conditions. Kds, whether sampled from probability distribution functions or calculated by regression equations or SCMs, can be used in many contaminant transport models. Alternate forms of the retardation factor equation that use a Kd (Eq. 1.5) and are appropriate for porous media, fracture porous media or discrete fractures have been used to calculate contaminant velocity and discharge Erickson (Erickson 1983; Neretnieks and Rasmuson 1984) as discussed in Sect. 1.3.3.

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In Situ Sorption Tests In situ (field) batch sorption tests use measurements of the contaminant contents of samples of rock cores and consanguineous pore water obtained at a field site to directly measure the partitioning of the contaminant between the solid and liquid. The advantage of this approach is that the water and rock are likely to be in chemical equilibrium and that the concentrations of any cations or anions competing for sorption sites are appropriate for natural conditions. Disadvantages of this technique are associated with limitations in obtaining accurate measurements of the concentration of contaminant species on the rock surface in contact with the pore fluid. Applications of this technique are described in Jackson and Inch (1989), Ward et al. (1990), Read et al. (1991), McKinley and Alexander (1993), and Payne et al. (2001). Colloids Colloidal suspensions are defined as suspensions of particles with a mean diameter less than 0.45μm, or a size range from 1  nm to 1μm. They represent potentially important transport vectors for highly insoluble or strongly sorbed contaminants in the environment if they are not filtered out by the host rock. In fractured rock, local transport of contaminants by colloids may be important. Two types of colloids are recognized in the literature. Intrinsic colloids (also called “true” colloids, type I colloids, precipitation colloids, or “Eigenkolloids”) consist of elements with very low solubility limits. Intrinsic colloids may occur near the contaminant source, where aqueous concentrations are solubility limited. Carrier colloids (also known as “pseudocolloids,” type II colloids or “Fremdkolloides”) consist of mineral or organic phases (in natural waters primarily organic complexes, silicates, and oxides) and microbial cells (biocolloids) to which radionuclides are sorbed. Degueldre et  al. (2000) and Honeyman and Ranville (2002) summarize techniques used to sample colloids from groundwater and to characterize particle concentrations and size distributions. Degueldre (1997) summarized the occurrence of colloids in groundwater from 17 different sites near a proposed Swiss repository site for low-level nuclear waste. Although locally and globally there are wide variations in colloid concentration and size distribution, several general trends can be observed. Many of the observed particle concentrations fall within the range 0.01–5 mg L−1; however, concentrations of >200 mg L−1 have been observed. There is an inverse correlation between particle concentration and particle size. Sorption of radionuclides and metals by colloids is affected by the same solution composition parameters discussed in the previous section on sorption processes. The important parameters include pH, redox conditions, the concentrations of competing cations such as Mg2+ and K+, and the concentrations of organic ligands and carbonate. The high surface area of colloids leads to relatively high uptake of radionuclides and metals compared to the rock matrix. This means that a substantial fraction of mobile contaminants could be associated with carrier colloids in some systems.

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The transport of radionuclides and metals adsorbed to microbes has been studied by a number of researchers (McCarthy and Zachura 1989; Han and Lee 1997; Gillow et al. 2000). Because of their small size (1μg/L, (b) probability >5μg/L, and (c) probability >10μg/L, with a resolution of 30  m (Ayotte et  al. 2012). More details about this study are found in the chapter by Zhang et al. (2021) in this book.

1.3  A  ssessment of Geoavailability: The Goal of the Environmental Pathways Analysis 1.3.1  Geoavailability Defined

We define the geoavailability of the contaminant as the relative amount, concentration, or volume of the original contaminant that reaches the exposed population at the system boundary. The geoavailability will influence the nature of the exposure and the toxicity of the material when it reaches the population. It will also be important in assessing the viability of risk management strategies such as monitored natural attenuation. The geoavailability of the contaminant is thus the input to the next portion of the medical geology analysis in the next chapter of this book (Siegel 2021). Processes that reduce geoavailability can roughly be divided into physical processes and biogeochemical processes. Physical processes include diffusion of contaminants into macro- or micropores or surface diffusion. These processes may lead to effective entrapment of the contaminant within the rock matrix or at a minimum, creation of very long travel paths, which are reflected in dispersion profiles with delayed leading edges and long tails. Matrix diffusion has been shown to be an important mechanism to reduce contaminant transport in fractured geomedia such as basalt and welded tuff (Neretnieks and Rasmuson 1984). Peak concentrations can also be reduced by simple dilution of the contaminant plume with groundwater from adjacent rock units. Biogeochemical processes include reversible and irreversible processes. Reversible adsorption partitions the contaminant between the solid and aqueous phases. As discussed later in the discussion of the retardation factor, this process will not remove the contaminant permanently from transport to the exposed population; it will only delay its arrival, with strongly adsorbed chemical species delayed more than weakly adsorbed ones. However, if degradation or immobilization processes are active, then this delay will lead to permanent reduction of the geoavailability. Contaminants may be also removed irreversibly from the fluid phase by several processes, including radioactive decay, biodegradation, “irreversible” sorption, precipitation, coprecipitation as well as volatilization.

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Box 1.3 Geoavailability Geoavailability: the absolute or relative amount of the contaminant released into the environment from a waste source to which a population can be exposed. Processes that reduce geoavailability: • • • • • • • • •

Dilution, dispersion Radioactive decay Biodegradation Volatization Precipitation Adsorption Matrix diffusion Occlusion Coprecipitation

Very strongly adsorbed species are effectively removed permanently for the purposes of many risk assessment calculations and may be considered “irreversibly sorbed”. For example, iron oxides and hydroxides are a primary adsorptive sink for many metal ions and metal oxyanion complexes in most soils. While adsorption of these metals is commonly rapid and efficient, desorption is generally slower, and often incomplete. As a result of this sorption hysteresis, there is a decrease in the labile, or readily available, fraction of metal ions in the system. Reduced mobility or near-immobilization of a number of metals and radionuclides has been demonstrated by experimental studies. Desorption studies with ferrihydrite, goethite, and other minerals using Mn(II), Co(II), Ni(II), Cu(II), Pb(II) (Coughlin and Stone 1995), Cd(II), Cr(III), and the metal complexes of arsenate, chromate, selenate, selenite, uranyl, and radionuclides, including strontium, radium, thorium, cesium, plutonium, and americium have demonstrated ample evidence for a sorption hysteresis (Bryan and Siegel 1998). Both carbonates (dolomite, calcite) and sulfates (gypsum and anhydrite) are likely to incorporate radionuclides in their crystal structure and remove them from groundwater more permanently than sorption onto clay minerals. For example, initial uptake of strontium by anhydrite can be modeled as reversible sorption (Ichikuni and Setsuko 1978). However, if the solution is supersaturated with gypsum, the Sr is encapsulated as further crystal growth occurs and the radionuclide is removed “irreversibly” from solution. This nonreversible “sorption” sequestration is not modeled with transport codes that rely on equilibrium assumptions but require explicit representation of chemical kinetics of the reactions. Mathematical treatments of the kinetics of sorption and desorption are found in Sparks (1986) and the studies of dissolution kinetics cited in Sect. 1.2.2.1. Many of the experimental studies are summarized in the publications by Ford and others (Ford et al. 2007a, b; Ford and Wilkin 2010). Note that even if the contaminants are slowly released from their host minerals, the time scale of such processes may be too long to impact the health of human populations.

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1.3.2  Contaminant Elution Curves As discussed, a number of natural and engineered processes can reduce the mass, mobility, or volume of contaminants or change its speciation after the contaminant leaves the source term and is transported in the environment on its way to a potentially exposed population. Figure 1.6 illustrates the effects of these processes on the relative concentration profile (or elution curve) of a contaminant continually released from a source term in a homogeneous porous media. The graph shows the relative concentration of the contaminant compared to the concentration at the source (C/C0) that is observed downstream at the boundary of the system of interest as function of the time. The units of time are expressed as multiples of the time it takes an inert water molecule to reach the boundary (i.e., the mean hydraulic residence time, tr). The boundary of the system might be the location of a potentially exposed population “down stream” from a contaminant source. For the case of ideal plug flow, at t/tr = 1, the concentration at the boundary reaches the concentration released from the source and remains at that level C/C0 = 1). In this illustrative example, these different processes have the following effects on the elution curve relative to ideal plug flow of the fluid. • Hydrodynamic dispersion: A small amount of the contaminant (the leading edge of the elution curve) reaches the boundary of the system before ideal plug flow and the concentration doesn’t rise to the level (C/Co = 1) until almost two times the mean hydraulic residence time. The latter, higher concentration portion of the elution curve is called the “tail.”

Fig. 1.6  Effects of dispersion, sorption and degradation on geoavailability. For the curve labeled “sorption,” the retardation factor = 4

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• Sorption: If the retardation factor due to reversible sorption equals a value of 4 (see Eq. 1.7), then in the absence of dispersion, the concentration at C/C0 = 1 arrives at the boundary at a time t/tr = 4 and remains constant. • Sorption  +  dispersion: The leading edge doesn’t reach the system boundary until after two hydraulic residence times; the tail is very long and full concentration doesn’t reach the boundary for at least 6 hydraulic residence times. The concentration is C/C0 = 0.5 at t/tr = 4. In the foregoing examples, as long as the source term remains constant, the concentration at the boundary will reach the initial source concentration eventually. However, if the contaminant is subject to radioactive decay or biodegradation, then its concentration will decrease over time and this will be reflected in the elution curves as shown in the figure. • Dispersion + degradation (either biodegradation, immobilization or radioactive decay): the leading edge arrives early, the concentration never reaches the initial concentration (C/C0 always 260 polymorphisms/gene have been catalogued. The DNA repair genes XPD312, XRCC1, APEX1, PARP1, ERCC2 have been commonly used in molecular epidemiology studies of geogenic contaminants such as arsenic and uranium (Yager et al. 2015). Rebbeck (1997) reviewed molecular epidemiological data that suggest that mutations in the GSTM1 and GSTT1 members of the glutathione-s-transferase supergene family increase susceptibility to bladder cancer and other kinds of cancers. It has been suggested that polymorphisms in the GST genes might affect both detoxification mechanisms and arsenic metabolism (National Research Council 1999). Additional examples are provided by Badawi et al. (1995), Taylor et al. (1998), Hoover et al. (2021) and Dailey and White (2021) in this book. 2.4.2.3  -Omics Technologies and the Exposome During much of the twentieth century, the biological basis of diseases was poorly understood, and biological plausibility was often a weak or black box in the causal chain. However, in the late twentieth and early twenty-first centuries, new concepts and technologies have provided much detail in the mechanisms of disease. Two important areas of development include the concept of the exposome and the use of -Omics technology (see Box 2.7). Together these ideas and tools have led to a meet-­in-­the middle concept of understanding the relationships between external exposure, internal exposure, and health effects (National Academies of Sciences, Engineering, and Medicine 2017). Box 2.7 The Exposome and -Omics Technology Exposome: the totality of a person’s exposure from conception to death. Exposome research involves the measurement of multiple exposure indicators by using -omics approaches. -Omics technologies include: Genomics: analysis of variations in the structure and function of DNA. Epigenomics: analysis of chemicals such as histones and chromatin that regulate gene expression. Adductomics: analysis of chemicals that bind to DNA or selected proteins Metabolomics: analysis of small molecules (metabolites) created from chemicals that originate inside or outside the body. Transcriptomics: analysis of RNA (mRNAs, noncoding RNAs, and miRNAs).

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As discussed previously, the exposome includes all internal and external exposures that people receive throughout their lifetime. This involves simultaneous assessments of individuals’ full spectrum of external environmental exposures and endogenously produced chemicals. These internally generated chemicals can be characterized with the biomarkers used in -Omics technologies. -Omics deals with the characterization of groups of biological molecules that control the structure, function, and dynamics of an organism. Initial -Omic studies explored the genetic basis of disease through genome-wide association studies in which the genomic markers in people who have and do not have a disease or condition of interest were compared. The -Omics technologies have expanded to now include many other biomarkers (Vineis et al. 2013). These include measurements of chemicals that bind to DNA (adductomics), changes in the structure and function of genomes (genomics), analysis of changes in changes in chemical structures such as histones and chromatin that regulate gene expression (epigenomics), characterization of metabolites or small molecules that are created from chemicals that originate inside or outside the body (metabolomics) and others. -Omics technologies are a key element in describing the exposome as well as used in understanding the susceptibility of individuals to disease. -Omics technologies can measure chemical or biological exposures directly or identify biomarkers of exposure or response that allow one to infer exposure on the basis of a mechanistic understanding of biological responses.

2.5  Environmental Epidemiology

Environmental epidemiology is the study of the relationships between exposure to environmental stressors and the distribution of disease or other health effects in space and time. The preceding sections of this chapter have described different types of information and associated tools important to understanding the relationships between the geoavailability of geogenic contaminants and health effects. All of the components in the Biological Impact Analysis described here are included in the field of environmental epidemiology, which provides rigorous methods to analyze this information. The basic concepts of epidemiology are found in texts such as Gordis (2000) as well as in previous editions of Essentials of Medical Geology (Nielsen and Jensen 2013) and will not be delved here in depth. However, a brief summary of some key concepts and definitions is reviewed in Appendix 2 of this chapter. The purpose of this section is to provide some examples of different study designs for

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environmental epidemiology in medical geology and to discuss the challenges and features of environmental epidemiological studies relevant to medical geology. It is important to note the differences between environmental epidemiology, occupational epidemiology, and infectious disease epidemiology. The latter two do not face the same methodologic challenges as environmental epidemiology (Rothman 1993; Vineis 2018). Assessments of current and historical exposure and health status in occupational epidemiology are often aided by required company records. In addition, results of occupational epidemiology studies may be affected by the “healthy worker effect” because the subject population may be healthier than the general population (see Chap. 23 in this book by Wålinder (2021). Vineis (2018) notes that although the basic origins of epidemiology lie in studies of infectious diseases (such as John Snow’s landmark study of cholera in London in 1854), the methods and tools of environmental epidemiology of communicable diseases differ from those used in the studies of the noncommunicable diseases important in medical geology. This is primarily due to the fact that whereas communicable diseases have short latency periods and have unique necessary components, diseases important in medical geology have long latency periods and multiple causes that are neither necessary nor sufficient. (See Appendix 2 for a discussion of the necessary and sufficient components in models of disease causality). Box 2.8 Causal Criteria in Medical Geology Geologic plausibility Temporality Strength Dose–response Reversibility Consistency Biologic plausibility Specificity Analogy Geologic Plausibility

At the heart of epidemiology is the goal of discerning potential causal relationships between exposures and health effects. Although associations between exposures and the prevalence or incidence of diseases can be observed, a causal relationship is posited only if certain criteria, first elucidated by Hill (1965), are satisfied (see Box 2.8 and Table 2.5). In addition to Hill’s original criteria, medical geology studies should include a requirement for “geologic plausibility.” This criterion focuses on the possible environmental pathways that make exposure to a putative diseasing-causing agent likely. The ideal epidemiological study would have comprehensive exposure and health outcome information, identification of important confounders, and little measurement error for the confounders, exposure, and outcome variables. Because most environmental epi studies are nonexperimental studies, these conditions are rarely met, resulting in major sources of bias as discussed in Appendix 2.

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2.5.1  Study Designs in Environmental Epidemiology Epidemiological studies can broadly be separated into descriptive and analytical studies. The former includes cross-sectional and ecological studies, where disease and exposure are assessed simultaneously, or the exposure and health status of individuals are not known. Because of these limitations, these studies can be used to develop hypotheses but typically do not satisfy the accepted criteria for proof of causation. In analytical studies, the disease and exposure status at the individual level and their temporal relationships are known. Analytical studies can be used to test casual hypotheses and to design intervention studies. 2.5.1.1  Role of Ecologic Study Designs in Environmental Epidemiology Environmental exposures often affect the health of many individuals simultaneously and therefore lend themselves to ecologic studies. These studies use aggregate data for groups of people rather than for individuals. Such groups may include census tracts, counties, states, or even entire continents. Estimates of the average exposures  and health status of populations within these groups  are readily  available from  on-line data bases. For example, the WONDER database (2003) provides information on deaths due to a variety of causes and can be aggregated at the State and county level  and further restricted based on age, gender and ethnicity.  The use of aggregate exposure information on such water-quality data for entire groups within a water distribution zone can be used as a proxy for individual exposures. However, the use of aggregate data introduces measurement error that will affect the analysis. Both the exposure and disease status may be heterogeneous within the units of study; there is no guarantee that any individual with high exposure will experience impaired health. Without information on exposure and health status of each individual, it is not possible to estimate the joint distribution of the two variables (Rothman 1993). An observed relationship between exposure and disease risk may not correspond to the biologic relationships between exposure, dose, and response. These errors give rise to the so-called ecological fallacy (Morgenstern 1982, 1995). The widespread use of ecologic studies in environmental epidemiology is due largely to the difficulty in obtaining high-quality exposure data for individuals over the long time periods associated with exposure and latency of chronic environmental diseases. As discussed in Appendix 2 and the discussion that follows below, ecological studies and cross-sectional studies, however, can be used effectively for the development of hypotheses especially when followed by analytical studies. 2.5.1.2  A  nalytical Studies: Cohort Studies, Case–Control Studies, and Nested (2-Stage) Studies As discussed in Appendix 2, cohort studies characterize the joint distributions of exposure and the health status of individuals in a population. In prospective cohort studies, exposed and unexposed populations are identified, and the subsequent

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health status of the populations is followed for a period of time. Such studies in environmental epidemiology can be very expensive given the long latency period of many diseases caused by environmental exposures. In retrospective cohort studies, historical health data for the populations exposed in the past are used to reconstruct the relations between exposure and health. These studies are quicker and less expensive to carry out but are more subject to several information biases, including recall bias, selection bias, and misclassification. Case–control studies (sometimes described as backward cohort studies) involve a comparison of the exposure histories of cases (people with a disease) and controls (people without the disease). They are effective for rare diseases and can be prospective or retrospective. Because analytical studies use comparisons of exposure and disease status of individuals, they can be used to get estimates of the absolute or relative rates of disease in the exposed and unexposed populations. They are considered more appropriate for testing hypotheses related to the causal criteria in the Box 2.8 and in Table 2.5. In two-stage studies, disease and exposure information are collected in the first stage to estimate crude rates and then information about covariates is collected from a smaller sample population in a second stage. This approach may be useful in environmental epidemiology studies where the influence of another factor (covariate or confounder) is suspected to be important but is difficult and expensive to quantify. 2.5.1.3  C  omparison of Descriptive and Analytical Epidemiological Studies: An Example A series of epidemiological studies of a population in the city of Antofagasta, Northern Chile, carried out over the last decade, illustrates the differences between the structure, limitations, and complementary roles of ecological and case–control studies. From 1958 to 1970, >100,000 people in the city were exposed to high levels (>850μg/L) of arsenic in their public drinking water supply. Subsequently, an alternative water source with low arsenic levels was used by the population. The epidemiological studies investigated the cancer mortality and incidence in adults 30–49 years old, who were in utero or children (18 years old or younger) during the period of high arsenic exposure. The studies examined a number of cancers and noncancers; the following discussion is limited to bladder cancer mortality and incidence. Example 1  Ecological study of relationship between bladder cancer mortality and early childhood and in utero exposure to arsenic in drinking water (Smith et al. 2012). • Exposed population: Residents of Antofagasta born in 1958–1970 and 1940–1957. Arsenic concentrations in this area were about 850μg/L during the exposure period of interest (1958–1970). • Control population: Residents of other parts of Chile born during the same time intervals. • Data sources: Mortality (deaths due to bladder cancer) and census data (populations) of residents of Antofagasta and all other regions of Chile from the Ministry of Health from 1989 to 2000. Data on potential confounders such as diet,

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s­ moking, and socioeconomic status were obtained from random sample surveys previously carried out by various government agencies on different portions of the population of Chile. • Calculation method: Standard Mortality Ratios (SMR) for deaths among those 30–49 years of age using 10-year age groups (30–39 and 40–49 years). The SMR compares the observed deaths in the exposed population to that expected in an unexposed (reference or standard) population for different age groups. The calculation of SMRs is illustrated in Box 2.10 in Appendix 2. • Results: Nine deaths from bladder cancer were observed in the population born 1958–1970; the expected number was 0.2; SMR for males =65.7 (95% CI: 24.1, 143); SMR for females = 43.0 (95%CI: 8.9, 126). • Conclusion: The large, stable population (>125,000), likely low errors in exposure classification or important confounders, and the high observed SMRs strongly support the conclusions of the study, i.e., that high exposures to arsenic in utero and in early childhood are associated with high levels of mortality due to bladder cancer later in life. The likely importance of the confounders and biases can only be indirectly inferred because data on these factors are not obtained on the same population as the mortality data. No dose–response relationship was obtained. Although potentially subject to the potential weaknesses of ecological studies described earlier and in Appendix 2, this study stands as one of the more successful using this design. Example 2  Case–control study of bladder cancer incidence in adults after in utero and early life arsenic exposure (Steinmaus et al. 2014). • Cases: Incident bladder cancer cases diagnosed between October 2007 to December 2010 for people who were >25 years old and lived in the study area at the time of diagnosis (N = 84–90). • Control: Controls without cancer were randomly selected from the 2007–2009 Chilean Electoral Registry for the study and were frequency matched to cases by gender and 5-year-age group (N = 286–332). • Data sources: All hospitals, radiologists, and pathologists in two northern regions of Chile discussed here provided data on cancer incidence. Arsenic exposure from drinking water was ascertained from data from municipal water companies for the relevant time period and an arsenic concentration was assigned for each year of the subject’s life. Cumulative and average exposures were calculated for each participant. Data on potential confounders such as diet, smoking and socioeconomic status were obtained for all participants from personal interviews. • Calculation method: Cancer Odd Ratios (OR) were calculated using unconditional logistic regression for subjects exposed to arsenic concentrations of 111–800μg/L and >800μg/L at birth or as children using subjects who were never exposed to >110μg/L as the reference. The model variables included sex, age, smoking status, occupational exposures, and several SES (socioeconomic status) variables. Logistic regression is described in Box 2.11 in Appendix 2. • Results: The bladder cancer incidence for those exposed only early in life to arsenic concentrations showed a dose–response relationship. Calculated ORs for populations exposed to 110–880μg/L and >880μg/L arsenic were 2.94 (95% CI:

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1.29–6.7) and 8.11 (95% CI: 4.31–15.25), respectively. Corresponding ORs for participants only exposed as adults were 2.21 (95%CI: 1.03–4.74) and 4.71 (95%CI: 2.62–8.48). More detailed analysis considering age at exposure, increases in cumulative exposure, and adjusted for age, sex, and smoking also showed higher ORs for those highly exposed in early life but not as adults. • Conclusion: The results of this analytical study provide strong evidence of the increase in bladder cancer incidence up to 40 years after the early childhood high arsenic exposures ceased. The analytical study design allowed for quantitative adjustment for a number of potential confounders and for estimation of a dose– response relationship. The potential for exposure and case misclassification was minimized by collection of data through personal interviews and individual hospital records. By providing results that are consistent with the results of the ecologic study described here, this study supports the causal nature of the relationship between early childhood exposures to high levels of arsenic and cancer incidence and mortality later in life.

2.5.2  Challenges in Environmental Epidemiology The nature of the subject matter in medical geology gives rise to several specific challenges in epidemiological studies. These include: • • • • •

Mixtures of environmental toxicants at low concentrations Different induction periods and dose–response behaviors for mixture components Long latency periods of chronic diseases Migration of populations over the long latency periods Small-scale spatial and temporal heterogeneity in external exposures

These characteristics work together to create challenges in exposure assessment and recognition of related health effects in environmental epidemiological studies. A long time period between exposure and the onset of disease makes it very difficult to link a putative agent to the disease, especially in retrospective studies. When there is significant interaction between the biological mechanism related to different causative agents, the difference in their dose–response curves makes it difficult to relate progression of a disease to the initial exposure. In their review of the IRIS for arsenic (National  Research  Council 1999), the National Research Council identified three cases where coexposure to other interacting contaminants in addition to arsenic could affect the results of an epidemiological study designed to assess health effects associated with arsenic exposure: 1. The study doesn’t include populations who are more vulnerable to the effects of arsenic due to coexposure to interacting metals. This would result in an underestimation of the risk to this group. 2. The study has arsenic concentrations that covary with other interacting toxic contaminants that are not measured. This would result in an overestimation of

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the effects of arsenic because some of the health effects would be incorrectly attributed to arsenic. 3. The study has interacting contaminants that are distributed randomly across the arsenic exposure groups. This would weaken or obscure the observed effect of arsenic exposure. High migration rates and low environmental exposures make detection of associated health effects difficult for diseases with long latency periods. Migration of individuals into or out of areas with higher environmental exposures can produce bias in the analysis because migrants and nonmigrants can differ in exposure and in disease risk. This is discussed in studies of the relationship between exposure to arsenic in drinking water and the prevalence of bladder cancer (Siegel 2004; Frost 2004). Bladder cancer has a long latency period and temporal ambiguity exists when migration rates in the subject population are high. It is unclear if the exposure preceded the disease; people could be exposed to high levels of arsenic in one area and then migrate to another area where arsenic levels are lower but where the bladder cancer is detected. If migration were random across the two groups (nondifferential misclassification), the effects of migration on ecologic studies are difficult to predict and the relative risk can be overestimated (i.e., bias the results away from the null) (Morgenstern 1995). However, in individual-level (cohort or case-control) analyses, this misclassification would result in an underestimation of the relative risk (i.e., bias is toward the null). Spatial and temporal heterogeneity of geological sources of contamination make accurate exposure assessments difficult. This may be important for ecological studies of geophagia and for geogenic contaminants in drinking water when the subject population relies on private wells. Several approaches are useful in dealing with these challenges. Limited budgets for sampling soils and wells can be aided by the use of geostatistical techniques to interpolate data from sampled locations to unsampled locations as described in the previous chapters by Siegel (2021), and by Zhang et al. (2021) in this book. Daily and seasonal variations in airborne contaminants can be measured using databases maintained by the USEPA and local health departments. Personal biomonitoring as described in the earlier section can be used to obtain records of external exposures; biomarkers can be used to obtain measurements of internal exposures over different time periods. The use of biomarkers discussed here provides valuable information to improve exposure assessments. These “built-in dosimeters” record the history of past exposures as well as provide indication of discrete steps in disease progression. Collection of life-history exposures within the framework of the exposome may help to address the multicausal nature of diseases associated with environmental exposures. Vineis (2018) suggests that the application of -Omics technologies and the exposome discussed in previous sections in the chapter can help untangle the complexities introduced by the multicausal nature of environmental epidemiology. Identification of clusters and outliers, which can pinpoint areas with high incidences of diseases, may be important in medical geology (Getis and Ord 1996; Zhang et al. 2021). Diseases such as cancer are often clumped together in terms of

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their incidence in space, time, or may be influenced by a space–time interaction. The challenge is to determine whether there exists an excess of disease incidence, or a cluster, above what might be expected by random chance alone. This problem is especially important for diseases with possible environmental causes for which sources and pathways of potential pollutants are unknown. Difficulty in detecting disease clusters are due to: (1) population densities are generally not homogeneous and clusters may appear due to high population density rather than due to real disease clustering and (2) geochemical and geologic data may also be incomplete and geologic media may be very heterogeneous on a scale important to the analysis. Clustering may be purely spatial, purely temporal or both. Searches for statistically significant clusters of adverse health events in space and time can indicate exposure to localized exposures to toxins and help pinpoint the location of the source. Useful statistical analyses include location/date methods such as Mantel’s test, Knox test, and others. In the Knox test, the time and location of each disease case is noted and for each possible pair of cases, the distances between them are calculated both in terms of times and space. If many of the cases that are close in time are also close geographically or vice versa, then there is a space–time interaction. This could be an indication that a disease is caused by some local agent that appears at specific times. See Cliff and Ord (1981) and Williams (1984) for reviews of space–time clustering tests.

2.6  Synthesis and Summary  ew Concepts of Exposure and Dose 2.6.1  N in the Twenty-First Century The National Academies of Science, Engineering and Medicine (2017) defined “exposure” broadly as the “contact between a stressor and a receptor at any level of biological organization (organism, organ, tissue, or cell)” (p. 12). In some ways, the distinction between exposure and dose has become arbitrary and the term “dose” may be unnecessary. The same report discusses recent advances in a variety of disciplines relating to the interrelationship among the fields of exposure science, toxicology, and epidemiology. A framework that describes a linear path from introduction of a “stressor” into the environment to the exposure–epidemiology interface and exposure–toxicology interface is illustrated in Fig. 2.8. The former interface occurs at the link between presence in the environment and exposure medium such as air, water, or soil. This interface has been discussed under the topic of geoavailability in the previous chapter, where it is described as the fraction of a contaminant released into the environment that is available for contact with a potentially exposed population. The second interface occurs where the exposure medium comes into contact with a human through external exposure. An example of the sequence of processes that links the external exposure to geogenic materials to internal exposure

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Fig. 2.8  A framework of for exposure assessment and dose assessment based on one proposed by the National Academies of Sciences, Engineering, and Medicine (2017; Fig. 2-1) for risk-related evaluations

and target exposure was covered in this chapter under the subject of bioavailability. This is defined as the fraction of adsorbed contaminant that reaches a target cellular site where damage actually occurs. Biomarkers of exposure that relate external exposures to internal dose include measurement of metals and other chemicals in bodily fluids and tissues. Biomarkers of effects are used to recognize preclinical manifestations of diseases and include a large number molecular biomarkers as well as changes in cellular function and morphology. There are multiple interconnecting paths involved in the source-to-outcome continuum. Simple demarcations between external exposure, internal exposure, target exposure, or dose have been refined by advances in technology such as computational exposure assessment, physiologically based pharmacokinetic (PBPK) modeling, and -Omics technology. These methods allow prediction of the internal exposure resulting from measured external exposure as well as inference of the external exposure from measurements of internal biomarkers and inverse PBPK modeling (see Bowers 2021, this book).

2.6.2  E  xposure Assessment Science and the Environmental Pathway/Biologic Impact Analysis The use of an Environmental Pathway/Biological Impact Analysis can provide a framework for exposure assessment and epidemiology in medical geology. Because the analysis is based on physical, chemical, and biologic processes, it addresses the criteria of geologic and biological plausibility needed to substantiate causality in epidemiological studies. Figure  2.9 illustrates the role of different measurements

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Fig. 2.9  Exposure assessment within the framework of environmental pathways/biological impact analysis

and analyses that can be used in exposure assessment as discussed in this and the preceding chapter. The figure also addresses the aspect of practicality in medical geology analysis by noting the relative costs and accuracy of different complementary components of analysis.

2.6.3  M  edical Geology, Risk Assessment, and Risk Management Risk assessment based on practical medical geology will recognize the assumptions and limitations of the tools used in both the geologic and biomedical worlds. Extrapolations must be made from limited data obtained in laboratory studies to field-scale or population-scale applications. For example, analyses of the behavior of metals in laboratory batch or column studies must be combined with geological characterization at a limited number of sample sites in a field location to make predictions of the movement of contaminants in the environment between a source of pollution and the potentially exposed population. The insights gained from geological studies can guide exposure assessment studies by providing an estimate of the geoavailability of the contaminant for human exposure. Geostatistical analysis and the collection of comprehensive exposure data in the exposome can provide the information to accurately assess the exposure of individuals to geogenic

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contaminants. Similarly, in vivo or in vitro toxicology studies on relatively simple laboratory systems must be extrapolated to make predictions of the effects of contaminant exposures on the health of the potentially exposed populations. Physiologically based geochemical modeling and extraction studies can help to estimate the bioavailability of ingested or inhaled contaminants, thus providing important links between external exposures, internal exposure, and dose. The use of -Omics technology provides several biomarkers to track the progression of biologic effects from initial exposure to clinical manifestations of disease. The Environmental Pathways/Biological Impact model and the attendant concepts of geoavailability and bioavailability are part of a heuristic, i.e. a technique or framework to find an intermediate or short-term solution to a problem through loosely defined rules. The problem here is the assessment of the risk posed by an environmental hazard and the solution obtained is not guaranteed to be the optimal final solution but instead is sufficient for screening purposes in a risk management process. Heuristics are important to risk analysis and perception by providing useful summaries or encapsulations of complex systems that can be easily understood. The heuristic of geoavailability captures the complex processes involved in environmental transport. Thus, if the geoavailability of a contaminant is low in site-­specific conditions, then it is reasonable to propose that the risk is relatively low. Similarly, the bioavailability, introduced in this chapter, is a heuristic that captures the complex chain of metabolic processes leading from exposure to a pollutant to the resultant health effects. If the bioavailability is low under specific conditions, then it is likewise reasonable to propose that the health risk due to exposure is low. These heuristics include the components of risk analysis described as the Risk Assessment Paradigm (National Research Council 1983, 1996, 2009; Clahsen et al. 2018). They encompass those aspects related to the physical and biological sciences but do not address the social, psychometric or institutional aspects of risk assessment (Clahsen et al. 2018). However, by providing a comprehensive treatment of the geologic and biomedical aspects, it may reduce the unrealistic perceptions of risk associated with dread and fear of the unknown risk factors (Slovic 1987). These other aspects of risk assessment are discussed in more detail by Hirtz (2021) in Chap. 3 of this book. The first two chapters in this book establish a comprehensive framework for the use of various tools in applied medical geology. The chapters in Part II of the book provide more details about the specific methods and provide a guide to the relevant literature. Each of the methods has limitations associated with their available data and inherent methodological assumptions; however, the use of these tools within a framework such the Environmental Pathways/Biological Impact Analysis facilitates evaluation of the magnitude and impact of these uncertainties. This information can then provide guidance on how to manage and communicate the most important uncertainties within the context of risk management and risk communication.

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 ppendix 1: Toxicology and Risk Calculations A Considering Bioavailability • Cancer risk can be generally expressed by the following equation: Excess lifetime cancer risk = ELCR = DI × CSF, where DI is the chemical daily intake and CSF is the cancer slope factor. • Noncancer risk can be calculated as Hazard Quotient = DI/RfD, where RfD is the reference dose. • The effect of contaminant bioavailability from soil ingestion to human receptors can be evaluated by making adjustments to the dose using the following equation: DIadjusted = DI × RBA. • Alternately, RBA can be used to make site-specific risk adjustments for cancer risk by using the following equation: CSFadjusted = CSFIRIS × RBA, where CSF is the slope factor. • Site-specific adjustment for noncancer risk can be calculated by the following equation: RfDadjusted = RfDIRIS/RBA. Alternatively, when the exposure frequency, exposure duration, and ingestion rates are specified, the RBA value is used to calculate the excess lifetime cancer risk (ELCR) and the hazard quotient (HQ) as (see ITRC 2017, Section 9.1.3.2 for more details) (Table 2.4): ELCR =



Cs × RBA × IR × EF × ED × CSF BW × AT × CF

HQ =



Cs × RBA × IR × EF × ED RfD × BW × AT × CF

Table 2.4  Terms for toxicology calculations Parameter Meaning AT Averaging time BW Cs CF CSF DI ED EF ELCR HQ IR RBA RfD

Body weight Concentration in soil Conversion factor Cancer slope factor Daily intake Exposure duration Exposure frequency Excess lifetime cancer risk Hazard quotient Ingestion rate Relative bioavailability Oral reference dose

Adapted from ITRC (2017)

Units or value Days (for cancer—70 years × 365 day/year; for noncancer— ED × 365 day/year) kg mg/kg, site specific 1.0E + 6 mg/kg (mg/kg day)−1 mg/kg day, chemical specific Years Days/year Unitless Unitless mg/day Unitless, site specific mg/kg day, chemical specific

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 ppendix 2: Basic Concepts in Epidemiology A for Medical Geologists Environmental Epidemiology Basics Environmental epidemiology is the study of relationship between exposure to environmental risk factors and the occurrence of disease. The purpose of this appendix is to provide an overview of basic concepts in environmental epidemiology to aid the reader in understanding the discussion of the subject in this book. More detailed descriptions of epidemiological study designs (Box 2.9) can be found in standard books on epidemiology (Gordis 2000; Szklo and Nieto 2000). Detailed descriptions of statistical techniques used in environmental epidemiology studies can be found in standard biostatistics texts such as Rosner (1995); an introduction to the use of Bayesian statistics in epidemiology can be found in Ashby and Hutton (1996). This technique was used in studies of exposures to uranium contamination on the Navajo Nation by Hund et  al. (2015).  In epidemiology, an important distinction is made between correlation (or association) and causation. The former is established using a variety of statistical depending on the type of population being examined and is subject to rigid rules of probability theory, which establish the degree of statistical significance of the association. The latter is evaluated by a set of criteria established by Hill (1965) in the mid-twentieth century as discussed here.

Box 2.9 Epidemiology Study Designs Observational—Descriptive • Disease surveillance and surveys • Ecological • Cross-sectional Analytical—Longitudinal • Cohort • Case-control Experimental • Clinical trials • Population (interventions)

Rates Both prevalence and incidence are used to describe the patterns of disease. Prevalence is the proportion of people in a population with a specific disease at a point in time (point prevalence) or over a given time interval (period prevalence). Incidence is the rate that new cases occur in a group who don’t have disease and are at risk over time.

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A variety of rates are used to describe disease occurrence, including: (1) Crude rates for the total population, (2) Mortality—or death rates (3) Morbidity—or illness rates, (4) Case Fatality—% ill who die, or (5) Adjusted or stratified rates. Stratification may be based on age, gender-specific, or age-adjusted (compared to a population with a standardized age distribution) and be used to adjust for confounders such as smoking, race, SES (socioeconomic status), ethnicity, or residence. Adjustment for age is important because many diseases are more common in the elderly, and this trend must be factored out to see the effect of environmental exposures if the exposed and unexposed populations have different age distributions. Standardized mortality ratios (SMR) are used for age-adjusted analysis as illustrated in Box 2.10 in a later section of the Appendix. Statistical Techniques Commonly used techniques include: • • • • • •

Discrete data analysis—2 × 2 tables Point estimation, interval estimation Tests based on distributions: Poisson, Normal, Chi-square, Student’s t-test Linear Regression Logistic Regression Techniques involving time-series analyses such as survival analysis

It is important to be aware of the correct distribution to be used in different circumstances that may important in medical geology. Thus, the Poisson distribution is used to analyze the number of occurrences of a rare disease in a population. The Normal distribution is considered the “gold standard” for comparing properties (means, variance) of two populations. This can be used to see if the health effects observed in exposed and unexposed populations are statistically different. The Chi-­ square and Student t-distributions are used as approximations to the Normal distribution for actual sample populations based on sample data sets, which may be relatively small for high levels of environmental exposures. Logistic regression is used to describe relations between combinations of variables (e.g., exposure, diet, income), and a dichotomous variable (e.g., disease or no-disease state) and is described in Box 2.11 in a later section of the Appendix. Statistical Significance Statistical tests are used to evaluate the probability that an observed difference in disease rates between two populations (i.e., exposed vs nonexposed) is due to chance alone. The measure of probability that the difference is due to chance is expressed as a p value. The usual standard in assessing the statistical significance of an association is p 1.00, then the risk is significantly elevated at the 0.05 significance level. In this study, however, this condition was not observed, the Null Hypothesis was not rejected, and increased risk for bladder cancer was not demonstrated for populations exposed to arsenic concentrations greater than 10μg/L.

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Analytical Studies In analytical studies, the disease and exposure status are known at the individual level. They can be used to test casual hypotheses and design intervention studies. In cohort studies, exposed and unexposed populations are identified, and the development of disease is followed over future time (prospective studies) or by reconstructing historical mortality or morbidity rates from vital statistics databases (retrospective studies). Compared to ecologic studies, these studies have less bias in exposure assessment, have known temporal relations, can measure disease incidence, and can monitor several health outcomes for a single exposure. Their disadvantages may include the required large size, long study times, high costs, and subject to loss of follow-up. In cohort studies, the relative risk is commonly calculated as: • RR = (disease incidence in the exposed population)/ (incidence in the unexposed population). In case–control studies, the cases of a disease in a population are identified and controls are identified who are comparable to the cases but lack the disease. The exposures of the cases and controls to the hazard of interest are then compared to estimate the odds ratio, which is calculated • OR = (odds of exposure in the cases)/(odds of exposure in the controls). Case–control studies are good for rare diseases and are relatively quick and inexpensive to carry out. They may suffer from biases in the selection of cases and controls and from information bias. Odds ratios can be obtained from discrete data using simple methods such as 2 × 2 tables. Logistic regression can also be used to obtain estimates of odds ratios as described in Box 2.11.

Box 2.11 Logistic Regression Logistic regression is a mathematical modeling approach that can be used to describe the relationship of several independent variables to a dichotomous dependent variable. For example, in many epidemiological studies, the dichotomous dependent variable is the probability that has someone has a disease or not. The value of the dependent variable can vary between zero and one. The logistic function is shown in the illustration here.

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The independent variables can be either categorical, ordinal, or continuous. For example, the independent variables can be gender, age, a level of exposure, or some other variable that is related to disease status. The logistic model is derived from the logistic function, by writing z as a linear sum as shown in the figure. Here the Xi’s are the independent variables of interest and a and b are constant terms representing unknown parameters. These unknown parameters are estimated based on data obtained on the Xi’s for a group of subjects in the epidemiological study. Thus, if we knew the parameters a and b and we had determined the values of the Xi’s for a particular disease-free individual, then we could use the formula to obtain the probability that this individual would develop a disease over some defined time interval. For cohort studies, the risk can be estimated from the logistic function; however, for case–control studies, only the odds ratios, not individual risks, can be estimated from logistic model. Whereas the risk is defined as the probability that the disease will occur, the odds ratio is the ratio of the probability that the disease will occur over the probability that the disease will not occur. Detailed description of this method can be found in standard biostatistics books such as Kleinbaum (1994).

Strength and Significance of Associations Both the strength of association (rate ratio) and its statistical significance must be considered in evaluating the results of an epidemiological study. Box 2.12 summarizes relationship between the rate (odds or risk) ratios and descriptions of strength of association as commonly accepted in epidemiology. The statistical significance of the association is evaluated by testing the Null Hypothesis (Ho): that no relationship exists between exposure and disease (e.g., the disease rate in the exposed population equals the disease rate in the unexposed population for cohort studies). Both the t-test for continuous variables and the Chi-square test for discrete observations are used in the hypothesis testing. Box 2.12 Ratio Strengths Rate rao

Strength

1.0

None

1.0 – 1.5

Weak

1.5 – 3.0

Moderate

3.1 – 10.0

Strong

> 10.0

Infinite

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Confounding, Bias, and Interactions Evaluation of the strength of association in epidemiology studies must also include consideration of likely bias, existence of confounders, and effect modification. Bias is a systematic error in the study that affects the validity of the measured association. Both selection bias in enrollment of cases and controls as well as misclassification bias, which can affect assignment of exposure and disease status, can be important. Other types of bias are described in Table 2.5. Confounding is the misleading appearance of association between the exposure variable and disease status due to the effect of another factor, which is associated with both the exposure and the disease status. A classic example of confounding is the apparent association between coffee drinking and pancreatic cancer, which is strongly influenced by the independent associations of smoking with both coffee drinking and the cancer. Confounding can be evaluated or corrected by a variety of techniques, including randomization, stratification (separate analyses on homogeneous subsets of the sample population that differ by the value of the confounding factor) or use of logistic regression, which controls for confounding factors through separate terms in the logistic equation. For example, incidence or prevalence of many diseases is related to age; therefore, subjects are often separated into distinct age groups (stratification) or disease rates are compared to those of population with standard age distribution (age-adjustment). The calculation of Standardized Mortality Rates (SMR) is an example of age adjustment and is illustrated in the Box 2.10 above. Effect modification or interaction results when the effect of the exposure is changed by the presence of another exposure variable. The magnitude of the combined effect of the two exposures differs from the effect expected from each exposure alone (i.e., multiplicative and not additive). For example, the rates of lung cancer associated with exposure to both asbestos and smoking are greater than the sum of the individual risks. Table 2.5  Examples of bias important in environmental epidemiology Type of bias Selection bias Misclassification bias Recall bias/ reporting bias

Surveillance bias Publication bias

Description Methods of selection of cases versus controls or exposed versus unexposed subjects differ systematically Systematically assigning incorrect exposure or disease status to subjects. Includes both differential (predominantly affecting one group more) and nondifferential misclassification Recall of exposure history is better in the cases compared to the controls leading higher apparent exposures. Conversely, underreporting of an exposure may occur due to negative attitudes and beliefs associated with certain behaviors Disease ascertainment in the surveyed population is better than in the general population Failure to publish studies that do not show a relation between environmental exposures and health effects

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Causal Criteria Even if an association is strong, statistically significant, and the study is free of the factors described here, the association must be evaluated against recognized causal criteria before concluding that a cause–effect relationship has been established. The classic set of causal criteria was proposed by Hill (1965) and is described in Table 2.6. In medical geology studies, the addition of the requirement of geological plausibility is important. Support for a proposed cause–effect relationship can also be reinforced by consideration and rejection of alternative explanations as well as by the use of different models for causality. Underlying models for causality in environmental epidemiology studies include (1) the host–agent–environment model, (2) the causal chain model (agent factors + person factors + place factors+ time factors), (3) web of causation model (disease develops as result of chains of causation composed of many links, which are the result of many antecedents), and (4) causal pies based on the multifactorial nature of causation, where some factors are identified as sufficient and others as necessary for the disease to occur .

Evaluation of Epidemiological Studies Evaluation of an epidemiological study should include the following questions: • • • • • • • •

What was the outcome (health effect)? How assessed? What was the exposure? How assessed? What was the study design? What was the study population (cases and controls)? What was main result? Statistically significant? Are results likely to be influenced by bias? Was confounding considered and controlled for? Which causal criteria are addressed?

Table 2.6  Causal criteria in epidemiologic studies in medical geology Criterion Geologic plausibility Temporality Strength Dose–response Reversibility Consistency Biologic plausibility Specificity Analogy

Meaning Exposure to putative agent is consistent with environmental pathways analysis Cause precedes effect Large relative risk Larger exposures associated with higher rates of disease Reduction in exposure associated with lower rates of disease Repeatedly observed in different settings Effect is consistent with current biological knowledge One cause leads to one effect Cause–-effect relation has been established for a similar exposure–disease relationship

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In addition to the use of clinical manifestations of disease as an end point, the current use of -omics technologies allows the use of many other endpoints in epidemiological studies. Table 2.3 describes examples of the different endpoints used in some studies and their associated study designs related to geogenic contaminants such as arsenic and uranium.

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Chapter 3

Assessing and Accepting Risk: Interdisciplinary Perspectives Frank Hirtz

Abstract  Risk is about the future, operationalized through risk assessment and management. Risk seems to have become a universally accepted concept applied in innumerable decision-making processes in science, technology, and politics. This chapter analyzes the origins and development of the concept of risk, illuminates the various, sometimes conflicting, paradigms of risk, tracks policies about risk and institutions of decision making as well as national differences, and adds a social science perspective to explain the seemingly unquestioned ubiquity of this term. It includes a debate about the precautionary principle and the role that different cultures and the dependency on experts play in resolving risk-related issues. Thus, this will provide some background as to why it is so perplexing that science-based approaches to coping with risk yield such an array of different results. Keywords  Risk · Uncertainty · Danger · Risk assessment · Risk managment · Value of statistical life (VSL) · Risk-normative aspects · Risk-conceptual history · Precautionary principle · Risk-governance · Reflexivity of risk

3.1  Introduction: Risk Overall Modern society deals with issues of risk, irrespective of where, when, in which realm, by and for whom they are identified. We employ risk assessment to detect and avoid unwanted consequences, inform stakeholders of their roles and options, and in so doing, endeavor to convey confidence and trust. Principally, the assessment-­ related processes should indicate that “things are under control” and that one ultimately can have confidence in the manner in which decisions are reached, taken and, finally, implemented. Contemporary society is also, among many other things, characterized by the central role that academia in general and natural sciences specifically have been assigned in defining options of both risk identification and mitigation. Hence, a tension emerges between when and under which conditions a F. Hirtz (*) Department of Human Ecology, University of California, Davis, Davis, CA, USA e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_3

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natural science–based approach ought to be the determining paradigm and decisive arbiter or whether other stakeholders and their methods and interpretations play a role in risk identification and ultimately risk management (Renn 2008a, b). At a very abstract level, successfully managing risk enhances security. Yet, the quest for and thus, also the concept of security are themselves expressions of modernity and cannot be taken for granted (Kaufmann 1970; Kaufmann and Wichum 2016). Consequently, this highly abstract synopsis of the present-day understanding of risk in contemporary societies easily conceals the irritations that emerge for decision makers when they have to cope with the many paradigms that conceptualize the risk/security in such a divergent manner. For example, the assessments of different stakeholders of the same phenomena are justifiably based on different data; different natural science disciplines present divergent calculations while based on the same facts; relevant different governmental decision-making bodies reach conflicting, yet enforceable, verdicts, each legitimized by accepted rules and regulations. Understandably for those responsible to finalize a decision, finding a clear way through this maze of possibilities, is an understandable request, However, it is worth reiterating that the challenges for coordination and learning in the public sector cannot themselves be reduced to an all-encompassing formula (Kaufmann 1991). It is for this reason alone one has to untangle the multifaceted dimensions of the concept of risk and its concomitant modes of decision-making processes. The World Economic Forum, e.g., annually compiles the “The Global Risk Report” to apprise the multifaceted and constantly changing landscape of major risks with an emphasis on a complex multistakeholder approach (World Economic Forum 2020). The evolution of the contemporary understanding and the consequences of risk will summarily be dealt with in Part II.  The social sciences have coined the term “Risk Society” (Beck 1986; English transl.: Beck 1992) to reflexively position, cope with, and institutionally master this overarching risk paradigm. A multifaceted reality emerged, and different organizational and institutional answers evolved to cope with these divergent risk paradigms which are presented in Part III. Out of the social concerns around seemingly endless manifestations of risk in society, Part IV deals with the concomitant normative facets in risk-related decision-making processes. In Part V, the discussion will turn to illuminate the high differentiation, or cultures, of risk assessment and the role that experts play in the virtually unquestioned acceptance and ubiquitous use of the concept of risk in contemporary decision making processes.

3.2  Evolution of Concepts of Risk 3.2.1  Pascal’s Wager The wide usage of the term risk emerged only in the later part of the twentieth century. It is anchored in a multifaceted history and carries a multitude of definitions and interpretations (Fischoff and Kadvany 2011; Hillerbrand et  al. 2012; Lupton

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1999). The quantitative notions of probability in philosophical and scholastic debates emerged in the late medieval and Renaissance periods, closely related to but different from the modern concept of risk. It advanced together with the rise of what we now call the (natural) sciences, where notions of probability/risk could play a role distinct from coping with the future through divination (Anjum and Rocca 2019; Hacking 2006; Luhmann 1990b: 702–719). In retrospect, the modern conceptual framing of risk is associated most prominently with the writings of Bernoulli and Pascal (Davison 2016; Hansson 1989, 2019; Pfitzer et al. 2006). “Pascal’s Wager” undergirds our present-day objectivist notion of risk. It expanded the notion of a pure probabilistic calculation as to whether a specific phenomenon might emerge by paying attention to the consequences of arriving on one side of a binary outcome. Pascal abstracted from the theological question whether (the Christian) God does or does not exist and whether logic provides the commensurate methodology to respond to this query. He proposed to answer the question with a resounding “yes” for the existence of God because it entails the likelihood of fewest negative consequences to agree with that outcome. In so doing, he relegated the issue of logic and veracity to a secondary, nondecisive, place when assessing the risk for being right or wrong (Douglas 1985; Hájek 2016b; Pfitzer et al. 2006). This method of analysis allows decision-making involving risk by merging the frequentist concept of risk (might an event occur) with an assessment about a judgment regarding the consequences of a possible event (Fig. 3.1). This combination provides the opening for invoking the precautionary principle (More below in Part IV). In the geosciences, the term risk gained importance in the 1960s together with the Natural Hazard Research (Bobrowsky 2013). Starting in the 1970s, approaches in the area of human/social geography and political ecology expanded the notions of risk to include the interaction of people and the environment and the resulting reflexive risk factors. (Weichselgartner 2002; Dikau and Weichselgartner 2014) Under the moniker ecology, originally understood as the “economy” of nature (Odum and Barrett 2005: 598), the combination, if not conflict, of natural and social sciences, the centrality of nature was questioned and reconceptualized, rendering it not any longer the single most important source of hazards, uncertainties, and, ultimately, catastrophes (Altvater 1987; Arrow and Fisher 1974; Beck 1996: 31).

3.2.2  The Risk Society The social sciences form part and parcel of the contemporary risk perception. Simply stated, humans now live in a “Risk Society.” This term was introduced in 1986 with great aplomb by the late Ulrich Beck, originally in response to the Chernobyl disaster (Beck 1986; Engl. transl. Beck 1992).1 He later expanded this to 1  Though this book has been translated into some 35+ languages, often republished in multiple (in Germany alone 12) editions, it is almost totally overlooked in the English-speaking world, especially in the US debate (See similar Adam et al. 2000; Rosa et al. 2014).

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Then

Now

The Original Pascal’s Wager Wrong

Believe

Heaven

Nothing

Not believe

Nothing

Hell

“God is or He is not…Let us weigh the gain and the loss in choosing…’God is.’ If you gain, you gain all, if you lose, you lose nothing. Wager, then, unhesitatingly, that He is.” - 165?

The Generic Pascal’s Wager Hindsight Right

Choices

Right

Wrong

Yes No

Risk-based decisions rely on an evaluation of future events for probable gains and losses. Many of these evaluations are in the generic form of Pascal’s Original Wager.

Logic or the Art of Thinking “So then, our fear of harm ought be proportional not only to the magnitude of the harm but also the probability of the event.” - 1662

Basic Risk Equation: Risk = likelihood x consequences

Fig. 3.1  Pascal’s Wager: then and now (Pfitzer et al. 2006: 2)

the concept of a “World Risk Society” (Beck 1997; Engl. transl. Beck 1999) According to Beck, the world turned into a risk society, due to human interactions, i.e., social interactions, with its environment. “Risks are always threats to future events that we may face. But as this constant threat determines our expectations, occupies our heads and guides our actions, it becomes a political force that changes the world” (Beck 1999: 29). His analysis argues against the inherent bias in technical/natural science-based risk assessments that can and often do differ from popular perceptions. In short, he posits that the governmental experts, steeped in and tied to the natural sciences, use a methodology that truncates the full range of risk elements, foremost to meet the demands of risk assessment formulas. In Beck’s understanding, three main types of risks prevail worldwide: financial crises, climate change, and international terrorism (Beck 1999: 37). The main characteristic of these is that they overlap each other, increase the dimensions of risk, and in so doing taint local concerns with global anxieties. Table 3.1 summarizes Beck’s arguments.

3.3  Variations in Assessment of Environmental Health Risks Concomitant to the further differentiation of conceptualizing risk in different academic disciplines, one can observe the surge of organizations and institutions that deal with risk-related issues. These are not only entities engaged in pure research, but also in the applied sphere of risk management in the government or private

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Table 3.1  Five major characteristics of risk in the contemporary era according to Beck Effects Transboundary effects

Characteristics Modern risk transgressed sectoral, social, national, and cultural boundaries. They may originate in one country or one sector will then proliferate into other areas sector (e.g., bovine spongiform encephalopathy, or BSE) Globalizing Risk tends to affect everybody and frequently involve irreversible harm (e.g., effects climate change) Increase of Risks tend to penetrate and transform social and cultural systems penetrating power significantly and change social behavior (e.g., genetically modified organisms in agriculture) Incalculable Due to the lack of boundaries and the complex global consequences of nature taking risks, the instruments and tools for calculated risks are inadequate and inaccurate so that even insurance companies are unable to calculate premiums that are proportional to the respective risks (e.g., nuclear power plants) Lack of Potential victims of risks are being unduly burdened without the consent and accountability without any fusion or person being accountable for future damage (e.g., car exhaust) Adapted from Rosa et al. (2014: 73)

sphere. These organizations span all levels of governance, from innumerable local administrations, regional, state, intrastate, and international organizations, either under the auspices of the UN or independent bodies. Add to these the whole gamut of manufacturing, service, and financial enterprises, and their umbrella organizations where the risk assessments are made, interacting with those mentioned here. One needs to add this almost overwhelming multitude of agencies to the outlined highly differentiated array of risk concepts to grasp the challenges in reaching any individual risk assessment. Leaving out here modes of risk management in the private sector, it is not surprising against this background that the many different institutions, mainly at the national level, reach dissimilar risk-related decisions (Aven and Renn 2010). This results in variations of policy formulations and outcomes, in some cases even within one governmental domain. Add to this complexity, the interdependent relationships within multinational organizational settings such as, e.g., the European Union. To gain a clearer view of this thicket of observable outcomes, Clahsen et al. propose eight different conceptual frameworks that are utilized in the decision-making processes by these different entities (Clahsen et al. 2019: 439–440). Table 3.2 can just but provide a glimpse of the multitude of theoretical approaches and conceptual theories that are currently employed to contextualize the many results. Each concept provides a logic for different outcomes, bewildering for the lay person and often irritating for the expert elite. As complex as these suggested eight dimensions are in and of themselves, one further needs to distinguish two further dimensions that precede each of the possible decision-making processes. First, countries select different risks for regulation. There are key differences in terms of the policy areas that are thought to require precautionary regulatory interventions. Second, in the event that multiple countries set out to manage the same risk issue, there can be differences in the stringency of

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Table 3.2  Eight conceptual frameworks and their properties to explain variation in international risk management strategies Name of conceptual framework 1. Risk Assessment Paradigm (RAP)

Disciplinary orientation of conceptual framework Analytical perspective used by expert risk assessors

Key ideas and issues brought forward by the framework •  Preferably quantitative assessment of risk numbers •  Separation of risk assessment (life science oriented) and risk management (normative, policy) •  Often interpretative ambiguity in risk assessment •  Different expertise toward Interdisciplinary field of 2. Research into the policymakers: pure scientist, science research dealing with roles advisory roles of of subject-matter experts in arbiter, issue advocate, broker of policy experts in risk management processes risk management processes alternatives •  Personal views/attitudes of experts (ARERMP) affect action perspectives. Distinction between (e.g.) science absolutist, technological optimist, environmental centrist, cautious environmentalist, environmental absolutist •  Expert roles context dependent, e.g., issue at hand and organizational environment of expert Psychological perspective on •  Evaluations of risks dependent on 3. Psychometric individuals’ risks construction Paradigm (PP) risk perception of the •  Focus on acceptability of risk by general public individuals •  Several, nonhierarchical, dimensions of risk acceptability •  Actors use heuristics in the evaluation of information and of risks •  Two dimensions of social 4. Cultural Theory of Sociological and Risk (CTR) anthropological perspective organization: grid and group •  Positionality leading to different risk on risk perception of lay assessment and management and follows people and culturally different types of social organization: determined (core) beliefs egalitarian, individualist, fatalist, hierarchist •  Different perspectives on “ecological stability” explain attitudes toward risk acceptability and management: (e.g.) benign nature, ephemeral nature, robust nature, capricious nature •  Different relationships between four ways of life and the four myths of nature emerge (continued)

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Table 3.2 (continued) Name of conceptual framework 5. Participatory approaches to risk assessment and risk management (PARAM)

Disciplinary orientation of conceptual framework Procedural frameworks combining analytical approach with social science risk research

Key ideas and issues brought forward by the framework •  Stakeholder involvement in risk assessment, management, and governance •  Concern assessment parallel to risk assessment •  Decision contexts and societal needs are starting points for risk issues •  Professional actors’ beliefs are 6. Advocacy Coalition Perspective from policy Framework (ACF) sciences hierarchal structured in a three-layered system: deep core beliefs, policy core beliefs, and secondary beliefs •  Actors with similar policy core beliefs cooperate in advocacy coalitions and implementation •  Different advocacy coalitions coexist, advancing their political agenda •  Information processing and 7. Social Amplification Integrative perspective drawing from multiple fields interactions between different actors of Risk Framework determine extent of social amplification of risk research (SARF) or attenuation of risks •  Different parts of messages, leading to different framings, evaluations of information, and definition of risks 8. Hofstede Model of Perspective focusing on how •  The culture of individual countries can be characterized in terms of six cultures differ between National Cultures dimensions: power distance, uncertainty countries (HMNC) avoidance, individualism, masculinity, long-term orientation, indulgence Adapted from Clahsen et al. (2019: 451–455)

the selected measures (Clahsen et al. 2019: 440). One can see these differences in the way in which the precautionary principle is applied in Europe and the United States (Wiener et al. 2011) or the variants regarding occupational health and safety regulations between EU member states (Rothstein et al. 2019). To the chagrin of practitioners who are anxiously awaiting clear directives, they are thus ultimately part of the complexity they want to reduce.

3.4  Normative Facets of Risk When dealing with the possible consequences of a decision, for those involved in the decision-making processes, one can distinguish between three distinct nontechnical aspects that influence a final conclusion. In common parlance one can ask, under which imaginable conditions will the proposed technical features of a design

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be safe—the safety principles embedded in a decision. Connected directly at any level of safety is the problem where and when one should draw a line of what exactly one should include or exclude in those safety considerations. These problems are nonintrinsic to the pure technical expertise and, thus, one looks for normative standards can guide those considerations—foremost the precautionary principle. And as the term principle already indicates, it involves the weighing of options regarding the assessment of consequences. Principally those are overall assessments that deal with the possible negative economic effects. However, particularly problematic among those are the economic value one associates with the (mainly loss of) life of affected people. This aspect is captured under the moniker value of statistical life (VSL) and is the third normative facet of risk decisions. In the reality of risk-­ related decision-making processes, such a discrete separation of these three normative facets does not exist, neither can they be ordered in any sequence of importance. Any possible outcomes of one aspect is, among other things, influenced by either of the two other ones in this example. In short, they interact under the conditions of complexity.2 Figure  3.2 illuminates some of these iterative decision-making processes.

The Igloo of Uncertainty Possible future events with known adverse outcomes Probabilities known

KNOWLEDGE

Closed KNOWLEDGE

I know enough

“CERTAINTY”

What can I know? What shall I do? What may I hope? What is the human being? [Immanuel Kant, 1800] Open KNOWLEDGE

Open IGNORANCE

I know something

I need to know

RISK Threat accepted or imposed

DANGER Threat neither accepted nor imposed

Probabilities unknown

IGNORANCE

Closed IGNORANCE

I do not I cannot want to know know GALILEO EFFECT

NESCIENCE

FIELD OF UNCERTAINTY

Fig. 3.2  The igloo of uncertainty (Tannert et al. 2007: 893)

 A concise of related issues in Making sense of science for policy under conditions of complexity and uncertainty | SAPEA (2020).

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3.4.1  Safety Principles In engineering, issues of safety are everyday concerns, hence also concerns about risk. Despite the substantial differences between the many different engineering and technical disciplines, one can parse out some general and basic ideas. The following three safety principles seem to be the prevalent ones: (a) inherent safety, (b) safety factors, and (c) multiple barriers (Hansson 2019: 6). Primary prevention, a different moniker for the “inherent safety” principle, points to the elimination of hazardous processes or materials at the first, safer processes in mechanisms or forms of manipulation of the risk of a hazardous event at the second and at the third levels, protective measures for those operating these technologies. Take as an example, a machine that needs a high level of heat (e.g., pumps of old make). Replace the original fuel with a safer one, at a secondary level, a different source of heat replaces the highly combustible heat source and at the third level, since still the enormous heat needed poses safety issues; hence, one establishes operating procedures, safety gear for the operators, and emergency protections measures. The “safety factor” principle (Clausen et al. 2006) in engineering refers to the margin at which a design increases the strength of a given technology over the pure needed strength to operate. Examples are the limitation of transporting loads set below the real capacity (lifts, lorries, etc.) These safety factors are often expressed in ratios, such as in buildings that can withstand x times the impact of an earlier, highest measured, earthquake. These ratios themselves are based on experience and reflect a combination of empirical experience, available data, and prevailing norms. (For example, building permits differ in their safety requirements in public or private buildings). The “multiple barriers” principle refers to a concatenation of barriers, ideally independent from each other as to safeguard their functioning irrespective of the functioning of any of the preceding or subsequent impediments. The nuclear waste disposal practices are a prime example (World Nuclear Association).3 The succession of barriers can be organized around a physical (from the inside out or vice versa) or a functional principle. Important for this principle is that the operation of one cannot be hampered by another barrier, e.g., the operation of sprinkler systems must be independent from the functioning of the emergency power supply. Though all these measures aim at reducing the risk of operating technical equipment under known circumstances and clear probabilities, unanticipated events (usually called accidents), however, are impossible to factor into these operations (Doorn and Hansson 2011).

3  https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-waste/storage-and-disposal-of-radioactive-waste.aspx.

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3.4.2  The Precautionary Principle Against the background of almost unfathomable, yet unavoidable and explicable, complexity in dealing with risk in the contemporary world, one overarching theme emerged. This theme attempts to guide one’s attitudes toward all risk-related issues. It is, in short, the normative realm of deciding for the future. “Risk calculations are the phenotype of the resurrection of ethics […] in economics, natural sciences and technical disciplines” (Beck 1992: 22). Risk, insecurity, hazard, vulnerability, danger, whichever notion one employs to denote the difficulties in deciding an action with future consequences, it ultimately compels the decision maker to confront an ethical dimension as to how to handle the effects of such a decision. In philosophy, the ethical demands placed on these decisions invoke the “Principles of Beneficence” where the notion to minimize potential harm for people that might be affected by someone’s decision (Ball and Mankiw 2007). Centrally, risk-related decisions invoke core values in public policy and social justice issues (Freeman 2019; centrally: Rawls 1971). To reach a decision with the highest degree of acceptance and yet staying within the strict parameters of the natural sciences, the almost universally accepted norm of the precautionary principle has been developed (Asveld and Roeser 2012; O’Riordan and Cameron 2017). Though it very likely originated in folk wisdom and other popular sayings,4 the contemporary usage reveals a differentiated view. “The precautionary principle forces to exaggerate the threat” (Ewald 2010) or in the words of a foundational philosopher writing about the modern society dependent on technology: “[i]t is the rule, stated primitively, that the prophecy of doom is to be given greater heed than the prophecy of bliss” (Jonas 1984: 31). Finding the right response to cope with the unstable relationship between uncertainty and knowledge is a long-debated issue in human history. First of all, the precautionary principle is just that, a principle but not an order, unless it is specifically legally enforced. One can define it as an action or policy that stipulated that a decision should not be implemented if, following the assessment of the available information, it may represent a threat of serious, irreversible, or unpredictable damage to the environment or human health. Consequently, the precautionary principle can be approached from two angles: the content, i.e., precaution, and its application, i.e., the principle. Part of the strategy entailed in the precautionary principle is the strategy, itself a norm, to diminish uncertainty by acquiring necessary knowledge related to the issue in focus. The principle, thus, turns into an ethical duty to diminish uncertainty to the extent possible (Bodansky 1991; Shrader-Frechette 1985). This, however, is a never-ending task, when one observes also the rule of rigorous skepticism (National Academy of Science 1992–1993). The quest for ultimate certainty clashes with a situation when  “better safe than sorry”; “look before you leap”; “a stitch in time saves nine”; “an ounce of prevention is worth a pound of cure”; “measure twice–cut once”; “It is better to be safe than sorry”; “The trodden path is the safest,” to name a few.

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decision makers cannot wait for this want of knowledge to be ascertained. Therefore, the application of the precautionary principle itself can create dangers, i.e., the assessment and quality of remaining ignorance that must be weighed against the benefits of accepting an achieved result as satisfactory. Different countries treat the role of precautionary principles differently resulting in considerable tensions not only within but also between nation states. As mentioned earlier, it is not only which policy areas were selected requiring regulatory intervention but also the stringency with which these regulatory measures in similar policy arenas are applied (Clahsen et al. 2019: 440). In the European Union, the precautionary principle in environmental and public health policies is mandatory (Marchant and Mossman 2004) and legislated in Art. 191 of the Treaty on the Functioning of the European Union,5 yet, the stringency with which it is implemented varies widely. At variance, the precautionary principle is not an all-­ encompassing policy of the regulatory institutions of the United States when it comes to risk regulation, but it is regionally and topically differentiated and kept in a tense, if often undecided, space between state and federal regulatory authorities. A US Supreme Court case (Industrial Union Dept., AFL-CIO v. API, 1980) opined that an agency has to demonstrate “significant risk” before regulating it (Wiener and Rogers 2002: 318). Since then, this presumed lack of an overall regulatory mandate in the US has been assumed to be the chief obstacle in concluding the Transatlantic Trade and Investment Partnership (TTIP) with the USA and the Comprehensive Economic and Trade Agreement (CETA) with Canada. However, it is likely that the highly different operationalization of the principle, depending on the type of risks, is the core reason that a compromise cannot be reached. Sometimes Europe does take a more precautionary stance than the US (e.g., genetic engineering: Myhr and Traavik 2002), but sometimes the US is the more precautionary regulator (e.g., mad cow disease in blood: Wiener and Rogers 2002). Applying the precautionary principle in our contemporary, highly technology-­ dependent, and globalized world not only results in complexity, but such complexity also makes failures inevitable. These negative consequences were appropriately coined by Charles Perrow as “Normal Accidents” for systems failures. He further asserts that typical precautions, adding to the already-existing complexity, may also help create new categories of accidents (Perrow 1999). The inescapable importance of expertise superseding without fully replacing experience deserves further scrutiny. It defines how contemporary societies do—or fail to—deal with risk.

3.4.3  The Value of Statistical Life (VSL) The contemporary interpretation of probability as a quantitative concept can be divided into three major groups of approaches: “(1) quasi-logical approaches: probability as a measure of objective evidential support; (2) degree-of-confidence or

 See also: http://europa.eu/rapid/press-release_IP-00-96_en.htm, https://eur-lex.europa.eu/legalcontent/EN/TXT/?uri=LEGISSUM:l32042.

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degree-of-belief approaches: probability as a measure of subjective graded belief or confidence; (3) feature-of-the-world approaches: probability as a measure for undetermined features of the world” (Hájek 2016a). This classical approach is based on the nature/society distinction whereby things in nature can be measured, analyzed, and thus, to a degree, predicted. Classifications of risk(s) follow the types of hazards one distinguishes, such as typhoons, earthquakes, floods, etc. Social aspects are included in this approach to the degree to which damage can or is likely to be inflicted upon the population in the proximity of a natural event causing harm. This approach consequently permits us to delineate precisely enough that segment of the society where damages might occur and, in so doing, allows us to construct arrangements of risk sharing in the form of damage compensation through voluntary or compulsory insurances that are linked to the specific natural catastrophe. But risk decisions not only estimate possible consequences for infrastructure and availability of resources, they also assess consequences vis-à-vis the quality of life, if not likely fatalities, of people. To render a result for the immense, foremost philosophical, conundrum to establish the value of a life requires a method to reduce this boundless complexity. The choice of such a method requires acceptance that goes beyond the correct assembly of appropriate facts. Coining and accepting the concept of the value of statistical life (VSL) to rate the value of such estimated fatalities is precisely such a standard that grew out as an answer to this normative quandary. The adjective “statistical” added to the notion of the value of life implies that there are rational ways to assess this value via means of calculations that transcend various policy arenas. The shift to making a statistical assessment permits to navigate the affective feelings and vagaries of compassion and eventually compassion fatigue. VSL permits to steer multiple agencies, institutions, and systems that are all autonomous, yet structurally coupled and that are all concerned with weighing cost benefits of different options (for the USA see: Hood 2017). In principle, the VSL operationalizes the core human right to protect each life as a central obligation of governments. This obligation gets severely tested when simultaneously more than one life is endangered. To achieve acceptable outcomes, VSL developed over last decades highly differentiated processes in a number of risk-related academic disciplines and different spheres of policy formation, yet, with considerable variations worldwide (Viscusi and Aldy 2003). Central to these differences are the assumptions about the divergent sensitivities in a given society letting the varying social values form part of the equations. VSL today is routinely used in the cost-benefit calculations of life-saving investments. According to Banzhaf (2014: 213), the term was coined in 1968 by Thomas Schelling to frame an issue in terms of a person’s willingness to trade off money for small risks and thus avoiding to enter the maze of establishing a specific value of life. The value of statistical life is measured by estimating how much society is willing to pay to reduce the risk of death. Without a standard concept, one best summarizes the approach this way: “For example, a policy to reduce air pollution in a city of one million people that reduces the risk of premature death by one in 500,000 for each person would be expected to save two lives over the affected population. But from the individuals’ perspectives, the policy only reduces their risks of death by 0.0002

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percentage points. This distinction is widely recognized as the critical intellectual move supporting the introduction of values for (risks to) life and safety into applied benefit–cost analysis (Ashenfelter 2006; Hammitt and Treich 2007). Although it is based on valuing risk reductions, not lives, the value of a statistical life concept maintains an important rhetorical link to the value of life insofar as it normalizes the risks to value them on a “per-life” basis. By finessing the distinction between lives and risks in this way, the VSL concept overcame the political problems of valuing life while remaining relevant to policy questions” (Banzhaf 2014: 214). To measure this willingness to trade off, however, different methods are employed and are hotly debated ever since (Ashenfelter 2006; Blomquist 2015; Majumder and Madheswaran 2017). Furthermore, the available multitude of approaches are  utilized by innumerable private risk assessment and applied research organizations that are employed in the public decision-making processes. This array of rules and players lead to very different real-life consequences. Summarily, these discrepancies accrue in three different spheres: the selection of preferences included in the calculations as well as the intrinsic selection of potentially affected (sub)-populations, which is partially driven by the biases employed in the selected preferences. Finally, government and international agencies based their final decision on whichever method without further justification (Viscusi 2012). In summary, though VSL has greatly enhanced the decision-making processes involving risks, it nevertheless conceals the underlying political norms that deserve to be available for the general public’s scrutiny (Pickett 2018; Simon et al. 2019).

3.5  Risk: A Social Science Perspective 3.5.1  Communicating Risk Physical, chemical, or biological facts must appear in a communicative social context before anyone, including the sciences, can deal with them. Likewise, one can communicate about a phenomenon such as risk if and only when it becomes communicable. Yet, communication is more than just the exchange of factual data between a sender and a receiver, for each communicative act entails, among other things, vagaries and thus the invitation to establish meaning and interpretation. These considerations form the foundation upon which one can formulate a title as “The Three Companions of Risk: Complexity, Uncertainty, and Ambiguity,” which precedes one of the chapters in a book about the risk society (Rosa et al. 2014: 131). This title denotes the cautionary note one needs to employ to a seemingly clear-cut science-based policy advice that employs risk calculations. Complexity, uncertainty, and ambiguity indicate the differentiated understanding of the concept of risk in the social sciences beyond just denoting the likelihood of an unwanted event with undesirable consequences. The following will delve into these forms of risk conceptualizations. Such an approach centrally indicates that risk, including its usage in the natural and engineering sciences, connects toward something of value for humans and is not just the calculation of a probable and purely possible event. It

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allows to distinguish between the “probability perspective” of risk and the “severity of consequence perspective” of risk.” The social science components have become embedded in the geosciences. In the geosciences, one associates the concept of risk with specific discernable events, such as floods, trajectories of tropical storms, breakdown of international air traffic due to the eruption of a volcano, the danger of avalanches for human transportation and their natural environment, and the effects of pollution and contamination for public health and natural habitats both in oceans as well as on terra firma. Summarily, one has labeled these as ecological risks. They represent an approach that takes spatial together with social issues into consideration and tries to model respective scenarios in which these spatially defined elements play a decisive role (International Workshop of the WHO-Collaborating Centre for Chemical Risk Management 1988; Peggion et al. 2008; N.N.—wikipedia.de 2018; Renn and Swaton 1985; Donovan 2012). Ecological risk research deals with physical as well as social aspects of dangers, risks, and catastrophes and attempts to adequately clarify the processes of the natural, i.e., physical and material aspects, as well as illuminating the consequences for social structures, actions, communications, and interpretations, thus bridging the physical/social divide. In other words, it is an approach that renders risk as a concept dependent on a specific perspective in which the observer cannot observe himself. Thus, risks become contingent forms of observations. What is defined as risk, and hence differentiated from something else, is always dependent on the observer or the observing system that observes something to be risky/at risk or secure and safe. Seen that way, risk spaces distinguish and denote risk with spatial attributes such as close/distant, here/there, or inside/outside (Egner and Pott 2010). Subjective (knowledge-based, judgmental) probability inserts uncertainty, a degree of belief that a certain event will occur. This probability is conditioned on some background knowledge of the person(s) involved in these deliberations. It reminds one of the Farmers or Sailors Almanacs of lore for collective memory has over centuries been the calibration of experiences into common knowledge (Aven et al. 2011: 1075; Anonymous 1851(?)). All in all, we can summarize the three-fold elements in the concept of risk: as a concept based on communication about events, consequences, and uncertainties (Verma and Verter 2007; Willis 2007); as a modeled, quantitative concept (reflecting aleatory uncertainties) (Kaplan and John Garrick 1981), and as a social construction (Aven et al. 2011: 1076; Luhmann 2005b).

3.5.2  Danger and Risk The concept of risk is discreetly different from the concept of danger. It denotes the case where future losses are seen not at all as the consequences of a decision that has been made, but are attributed to an external factor (Luhmann 1991: 30–38, 2005a: 101). Danger denotes the general quality embedded in the future, whereas risk is a specific approach to this overarching quality. In this approach, it is not any longer the distinction between risk and safety (or security) but between risk and danger, for there is no action without danger, yet risk is dependent on a specific selection of a

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particular action (Luhmann 2005a, c; Castel 1991; Douglas 1990). Put differently, danger is a state independent from one’s actions, regardless whether consequences occur or not. Research, consequently, must ascertain the conditions under which dangers are transformed into risks. These two paradigmatic approaches differ foremost in their characterization of social actors in risk situations. In the natural sciences, humans are a “black box” that, as a potential victim of a natural disaster, does not enter into the calculations regarding the chosen event. Any activities to be bundled in causations for such events are omitted. In contrast, the social sciences posit reflexively acting people into the center of the investigations in order to understand the logic of their actions (including methods of analysis and knowledge generation) in relation to and within the context of situations that then can or cannot be labeled as risk (Bonß 1991). Krohn and Krücken coined the term “evolutionary risks” for those that appear in a specific context and simultaneously change the very context in which they appear (Krohn and Krücken 1993: 8). These are risks that do not refer to historical experiences (e.g., observed frequencies) but are open-ended estimations of possible future events. Evolutionary risks can’t be compared. What could be compared to forest destruction by acid rain, climate change, tropical rainforest deforestation or the consequences of storing radioactive materials for future generations.6 One can discern three consequences of noncomparable risks: first, one cannot firmly assess whether a specific damage will occur but one is insecure about the security of the assumptions (Funtowicz and Ravetz 1990); Secondly, it shifts the causality of risk from the decider of an action to the one potentially affected by a decision. Note that the possible victims can be generations in a very distant future (e.g., consequences of nuclear waste storage); Thirdly, it modifies the relatively secure calculable incident of risk into one that needs to be negotiated with the observations and feelings of lay observers (Roeser 2012). “The observer of a decision maker may assess the risk of a decision differently from the decision maker himself; [who] above all, does not share in the advantages of the decision to the same degree as the decision maker himself” (Luhmann 1993: 328). It is foremost this communication between the potentially affected population and the decision makers, the experts, that attracted the attention of social scientist.

3.5.3  The Role of Experts and Acceptable Risks The end of the 1990s saw a new era of expert domination in risk policies, while at the same time, many policy analysts and social scientists warned that ignoring public perception may not only alienate those who have a stake in the decision-making process and violate democratic principles, but it also may underestimate the potential input into the decision-making process that the public could provide (Dietz et al. 1989; Jasanoff 1999).

6  It would lead to the paradoxical demand that one must wait for (or induce) a specific disaster in order to gauge whether one should avoid it.

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This leads to the questions about how to assess the acceptance of those risks by the population and how to construct the form in which a specific decision should be executed, in case it seems to be necessary and unavoidable to implement. Acceptability thus is dependent on factors that go beyond statements of probabilities. Starr proposed a formula that would allow us to calculate acceptance and answer the question “How safe is safe enough?” (Starr 1969: 204; Lowrance 1976) by setting into a relationship (e.g., in the case of erecting a nuclear power plant) the risk of death and the concomitant costs to avoid risks. As discussed previously, there is a rich literature in the insurance and actuary fields about the “value of a statistical life” (VSL) as the reigning concept to manage the attendant issues—ethical quandaries notwithstanding (Hansmann and Viscusi 2006; Kniesner and Viscusi 2005; Machina and Viscusi 2014; Viscusi 2006, 2011; Viscusi and Aldy 2003). Social science research tried to overcome the differences in conceptualizing risk between the reality of experts and the perception of lay people with psychometric research, useful for public hearings, especially in assessing the credibility for the public concerning decision-making institutions (Riesch 2013; Slovic 2000). Increasingly, social science research was concerned with enabling successful communication between the social sphere and the scientific world. A different conceptual architecture was introduced by Luhmann who proposed to forego the coupling of risk and security and instead distinguish risk from danger (Luhmann 2005b: 26). It seems to be easier to distance oneself politically from danger than from risks—even where the loss or the extent of loss is greater in the case of danger than that of risk (Okrent 1980). Consequently, in order to mitigate the awareness of the people involved, this distinction is both based on and allows for a focused communication about risk. Take the difference of perception in communication about, the Tohuku earthquake from 2011 with the Fukushima nuclear disaster caused by the same earthquake (Lidskog and Sundqvist 2013: 91). Issues that arose out of the Fukushima disaster were concerned with prices concerning energy and economic compensation in Japan. As a separate issue, the competence of decision makers we referred to the political system while the legal system dealt with issues of code violations and liabilities. The communication about victims of the earthquake were just the 15,000 lives. A tragedy does not fit into a public decision-making category. This goes to show that an event does not create itself, it becomes socially apparent and relevant only through communication. Risk, in this conceptualization, is defined as the attribution of an undesired event of possible future loss. This makes risks an intrinsic part of modern society that is characterized by a high functional differentiation. What this means is that, as in this example, different aspects of an event are both produced by and simultaneously dealt with in distinct, functionally differentiated domains, i.e., systems. The political system distinguishes itself in its functioning from the legal and the economic system. While victims of any event are affected as an entity, each of them individually and as a group has to interact with the different social system through different forms of communication. Hazards can either be attributed to the system as a whole (risk) or to something external to the system (danger) (Luhmann 1990a). Thus: “Those who take the decision face a risk; whereas those who are victims face a danger, that is, those who perceive themselves as exposed to something that they

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cannot control. Uncertainty is intrinsic to both risk and danger; the difference lies in who is seen to be a decision maker” (Lidskog and Sundqvist 2013: 91). “Affected parties thus develop theories of their own on the risky behavior of decision makers and the decision makers produce theories on the protest behavior of those affected by their decisions. One has experience in this field, and there are indeed possibilities to refine such explanations, to improve them, to render them more complex, and to make them more easily comprehensible. But this then raises the levels of complexity and opaqueness in the shared universe and certainly does not lead to consensus in the sense of a coincidence of system states” (Luhmann 2005a: 230).

3.6  Summary Can one demand certainty or request the absence of risk? If not, how do we justify the demand, at least, to reduce risk to the degree possible? How are the processes organized and legitimized to achieve a satisfactory outcome to meet the demands? Are there limits as to what one can wish for? (McLeod 2019). These are some of the remaining questions that the foregoing text did not answer, and likely in principle, are not answerable. For one, the dimensions of risk are constantly, as the foregoing shows, under evolutionary stress. Secondly, the broadening risk realms carry the unforeseen modifications, and in some cases even a revision, of the concept of risk. The highly complex social differentiation together with the globalization of society, especially the last 150 years, increased both the need for and the ambiguity in risk assessment (Johansen and Rausand 2015; Bradley 2019), leading to a reassessment of the role of experts that can assure us about future events (Collins et al. 2008). Risk considerations have become ubiquitous regarding judgment and decision making (Fischhoff 2012) and are diverse and differentiated hallmarks of policing and regulating risk decisions (Ericson and Haggerty 1997). In other words, one must get used to the fact that simultaneously the results of risk assessments become more refined and accepted as well as more debated and rejected. This includes the consideration that humans, as a species, are the original incalculable risk factor. Acknowledgments  I am grateful to Malcolm Siegel for his intellectual engagement with my topic, his support, and his editorial help. Thanks to Diane L. Wolf and Leora Jaeger for their editorial advice. I dedicate this essay to Prof. Dr. Franz-Xaver Kaufman, my teacher and mentor, who introduced the topic of security to sociology.

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Part II

Methods in Practical Medical Geology Malcolm Siegel

Introduction The chapters in Part II describe specific analytical, experimental, and computational methods used in a medical geology study in more detail. The goal in presenting these chapters is not to make the readers experts in these sophisticated geological and biomedical techniques, but rather to present the basic principles, methods, strategies, and limitations of the tools that might be used in a practical medical geology investigation. By introducing the concepts and terminology commonly used in the biomedical sciences, we hope to facilitate the participation of medical geologists in multidisciplinary teams important to practical applications of medical geology. Conversely, by introducing biomedical specialists to the way that earth scientists understand the movement of metals in the environment, it is hoped that better assessments of possible contaminant exposure routes could be made. The tools described in this section of the book are used to study properties and phenomena on spatial scales ranging from angstroms to kilometers. The methods range from spectral analysis of mineral surfaces to characterization of the bulk chemical properties of soils over many kilometers. They include the detection of damage to individual strands of DNA to the behavior of populations of thousands of people.

M. Siegel Department of Internal Medicine, University of New Mexico, School of Medicine, Albuquerque, NM, USA LJS Consulting, Sandia Park, NM, USA

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Fig. 1  The spatial scale of investigations in medical geology spans many orders of magnitude. (a) Studies of atomic scale interactions reveal the speciation of uranium on mineral surfaces (from Massey 2021, this volume). (b) Activity patterns of children provide information about their exposure to metals like lead via the ingestion of soils (geophagia). (c) County-level ecological studies of low birth weight occurrence can be linked to concentrations of lead in soils through geostatistical analysis to evaluate the relationship between health effects and exposures (from Zhang et al. 2021, this volume)

An important point emerges from this section: medical geologists must deal with the extrapolations and resultant uncertainties that underlie both the geological and biomedical sciences. For example, predictions of the environmental transport of contaminants that lead to exposures of populations must rely on inferences drawn from simple laboratory studies applied to field studies of complex systems. Similarly, assessments of potential health effects often rely on in vitro or in vivo studies of simple systems that are applied to epidemiological studies of complex populations. Medical geologists are uniquely prepared to manage the uncertainties that result from the limitations in both scientific realms. Chapters 4–7 provide methods and examples of techniques used to characterize the environmental behavior of toxins with an emphasis on metals and metalloids such as uranium and arsenic.

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Chapter 4 provides a detailed geochemical framework for the assessment of metal mobility in the environment. Using examples from legacy mining site in the Southwest America, this includes hydrogeochemical site characterization, analytical techniques, and laboratory experiments to determine solubility, sorption behavior, and colloidal transport of metals in groundwater. The mobility, toxicity, bioavailability, and health risk associated with contaminants such as chromium, uranium, and lead depend greatly on the specific chemical form or speciation of the potentially hazardous substance. Chapter 5 discusses the application of X-ray spectroscopic approaches for metal speciation that can be used for risk analysis of contaminated sites. These include X-ray fluorescence (XRF) spectrometry, X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Chapter 6 describes a multidisciplinary program to identify key factors affecting the environmental mobility of complex metal mixtures found at abandoned uranium mines and to assess the resulting toxicity based on the combinations of metals in the mixtures. The chapter examines the site-specific characteristics that influence the mobility of metals in the environment, estimates the resulting community-level exposures to metal mixtures, and investigates the biological mechanisms that underlie mine-waste metal toxicity using population-based studies, molecular mechanistic studies, and controlled animal studies. Chapter 7 describes the role that geospatial analysis can play in practical medical geology. Environmental samples in medical geology are generally collected at a limited number of points, which need to be converted to spatial distribution maps for practical uses in management as well as for scientific interpretation. Geostatistics provides an effective way to estimate the values at un-sampled locations, so that the estimated values can be used for the production of spatial distribution maps and then correlated with observed public health data such as disease incidence or prevalence. Chapters 8–10 deal with biomedical methods useful in practical medical geology. In Chap. 8, operational definitions for bioavailability and the closely related term bioaccessibility are given for three pathways by which chemicals can enter the body, namely ingestion, inhalation, and dermal absorption. An extensive review of available studies and techniques is given, and a case study of how bioaccessibility measurements can be put to practical use is given on the bioaccessibility of arsenic in Southwest England. Biokinetic, or pharmacokinetic, modeling can be used to link environmental exposures to chemicals to levels observed in blood, urine, or other body compartments. Chapter 9 reviews a variety of predictive models ranging from simple slope factor models to complex biokinetic or pharmacokinetic models. This chapter focuses on information pertaining to soil ingestion rates, which is one of the primary routes of exposure for young children to environmental contaminants and on lead and arsenic bioavailability to humans. Biomarkers are chemicals or biological molecules that are indicators of internal exposures, disease status, or preclinical precursors to the onset of disease. Chapter 10 introduces the theory and application of current biomedical techniques used in

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research and diagnostic laboratories in order to assess biological impact of environmental exposures through measurement of a variety of biomarkers. Medical diagnoses in a local population may be the first indication that environmental hazards or conditions are responsible for adverse health effects. Chapter 11 provides case examples of the structure of medical diagnosis for several common ailments that were related to geogenic contaminants. These include fatigue (iodine), weight loss (arsenic), behavior change (lead), and a persistent cough (coal dust).

Chapter 4

Techniques for Assessing Metal Mobility in the Environment: A Geochemical Perspective Sumant Avasarala

Abstract  Understanding metal mobility is very important for understanding the fate, transport, and toxicity of metals that negatively impact health of humans and other living organisms. The behavior of metals released from former mining sites is of particular interest in applied medical geology. The goal of the current chapter is to provide a detailed framework for assessment of metal mobility in the environment. Specifically, the chapter discusses a step-by-step approach to assess the geochemistry of a site, using relevant examples from mining legacy. The framework discussed in this chapter includes recommendations for site characterization, analytical techniques, laboratory experiments, and the identification of challenges for investigating metal mobility in the environment. Furthermore, limitations of some of these proposed techniques and alternative complementary approaches to overcome these limitations will also be presented. The chapter is intended to provide sufficient knowledge to members of non-geochemistry/geology disciplines to learn and acquire a reasonable understanding of different geochemical tools that are available to assess the mobility of metals and metalloids. In addition, the extensive bibliography of the chapter should provide a representative sample of the extant literature on this topic. Keywords  Metal mobility · Transport · Geochemistry · Site characterization and analytical techniques

4.1  Introduction Metals as are typically thought of as malleable and ductile materials that are good conductors for heat/cold and electricity; however, metals exist in a variety of complex forms in the environment. They are essential components of both the human

S. Avasarala (*) Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, USA e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_4

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body and the natural resources (air, water, and soil) that are fundamental to all living organisms. The tendency of metals to participate in different oxidation-reduction (redox) reactions is essential to generate the energy necessary to induce metabolism and sustain major life processes within the body (Monosson 2012). Under favorable conditions, metals can be mobilized/immobilized through phase transformation, i.e., from solids to dissolved species to and vice versa; which depend on (1) structure, (2) property, (3) kinetics (mass transport), and (4) thermodynamics of the reactants and reactions (Porter et al. 2009). Thus, understanding the mobility of metals is important in several different scientific disciplines. For example, in the field of medical sciences, it is important to monitor the iron content in blood, which determines if a person is healthy, anemic (De Benoist et  al. 2008), or suffering from hemochromatosis (Barton et  al. 1998; Witte et  al. 1996). Similarly, kidney stone formation due to biomineralization (precipitation) of calcium oxalate mono or dihydrate solids (Wesson and Ward 2007), and usage of mesoporous silica nanoparticles for targeted delivery of drugs (Wang et al. 2015), are a few other applications where metal mobility is important in the biomedical sciences. In other scientific disciplines such as geology, geochemistry, environmental engineering, life sciences, and others, metal mobility is typically studied for contaminants that are potentially toxic to humans and other living organisms. In this context, mobility refers to how a contaminant is transported from one environmental reservoir (e.g., rock or soil) to another (e.g., air or water) through physical and chemical processes that may increase or decrease toxicity to living organisms. Metal mobility often depends on the chemical speciation of metals, i.e., their oxidation state and bonding environment (Baran and Tarnawski 2015). For example, metals and metalloids like uranium (U), arsenic (As), lead (Pb), and chromium (Cr) are toxic and carcinogenic at low levels of exposure through air, water, and soil; however, their biological pathways for causing their toxic effects are different (Andrew et al. 2008; Keith et al. 2013; Richard and Bourg 1991; Stohs and Bagghi 1995; Tchounwou et al. 2012; Zota et al. 2009). The U.S. Environmental Protection Agency (USEPA) takes toxicity into consideration to define maximum contamination limit (MCL) (USEPA 2018b) or total maximum daily load (TMDL) (USEPA 2018a) for many such contaminants in groundwater, drinking water, and surface water. The toxicities of metal contaminants depend on several factors, including dose, route of exposure, age, gender, genetics, chemical speciation, and nutritional status of exposed individuals (Tchounwou et  al. 2012; Baran and Tarnawski 2015). Metal mobility is a very broad topic, but for the sake of specificity, the rest of the chapter will focus mainly on common trace metal(loid) contaminants such as U, Pb, Cr and As from geologic and geochemical perspectives. Note that although As is classified as a metalloid, it will be treated as a metal in the discussions that follow.  The mobility of trace metals such as U, As, Pb and Cr in the environment is affected by a variety of geochemical and physical processes. Geochemical processes are based on chemical transformation of metal species, whereas physical

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processes depend on advection, dispersion, and diffusion, which are properties of water flowrate, metal particle velocities, and gradients in dissolved metal concentrations (Gillham et  al. 1984; Anderson 1984). Chemical mechanisms such as sorption, dissolution, and precipitation involve the transfer of metal species from water to solid surfaces (adsorption) and vice versa (desorption), and dissociation (dissolution) of solid metal species into anions and cations and vice versa (precipitation), under favorable conditions. These processes occur at the solid–liquid interface and are typically driven by physicochemical properties that include pH, redox potential, temperature, reaction kinetics, and elemental composition of the system (Gerke et  al. 2009; Langmuir 1997; Maurice 2009; Stumm and Morgan 2012). Additionally, chemical processes depend on several other characteristics such as trace, minor, and major element aqueous speciation, and the crystallinity, speciation, and structure of solid mineral phases (Avasarala et al. 2017; Baes and Mesmer 1976; Burke et al. 2012; Holyer and Baldwin 1967; Langmuir 1997). The constant exchange of metals at the solid–liquid interface and their underlying complexities makes it challenging to understand metal mobility. Specific details on each of these processes and concepts are discussed with relevant examples in Sect. 4.2.1.1 of this chapter. Development of numerous analytical techniques in environmental sciences and technology has improved our ability to assess metal mobility. For example, advances in spectromicroscopic techniques such as scanning transmission X-ray microscopy (STXM), transmission X-ray microscopy (TXM), X-ray photoemission electron microscopy (X-PEEM), and scanning photoelectron microscopy (SPEM) (Stuckey et al. 2017) make it possible to determine the spatial association of metal species in complex organo-mineral assemblages (Avasarala et al. 2019) within soils. Similarly, development of synchrotron spectroscopy techniques allows us to investigate low-­ temperature geochemical samples, which include in situ investigations of aqueous samples and organic matter–metal interactions, without affecting sample integrity (Fenter et al. 2018). Information from such techniques can add significant value to interpret or support observations made in laboratory/field experiments. The objective of this chapter is to provide a framework for applying such methods and techniques to investigate the mobility of metals in the environment (U, As, Pb, and Cr) by presenting relevant examples from geochemistry. Because the environmental impact of metal releases from historical mining sites is so important to applied medical geology, many of the examples are taken from studies relevant to such sites. In addition, limitations of each of these methods will be discussed in sufficient detail and alternative complementary approaches to overcome some of these limitations will be presented. This chapter will serve as an introduction to the topic for people in non-geochemistry/geology disciplines, helping them to acquire a reasonable understanding of different geochemical tools that are available for assessing transport of metals in the environment. In addition, the extensive bibliography should provide a representative sample of the extant literature.

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4.2  General Framework for Characterizing a Site Metals in the environment occur in complex matrices like rocks, sediments, and water that are constantly exposed to dynamic reactive conditions. Therefore, it is important to understand the site chemistry, geology, and soil matrix before characterizing the solid and liquid samples collected from the site. In this section, the general site chemistry, field techniques, sample collection, and sample preservation techniques that form the fundamental framework toward characterizing a site are discussed.

4.2.1  General Chemistry 4.2.1.1  Site Chemistry To understand the inherent complexity in environmental systems, it is important to consider the basic site chemistry. Site evaluation may include chemical characterization of soil, water, air and/or vegetation. Reviewing previous literature related to the area can be helpful as an initial step. Examples of chemical databases include the U.S.  Geological Survey National Water Information System (NWIS) (USGS 2018a) and Mineral Resources Online Spatial Data (USGS 2018b), U.S. Department of Agriculture’s Soil Survey Geographic database (SSURGO) (USDA 2020), National Atmospheric Deposition Program (NADP 2020), EarthChem (IEDA 2020), and the Water Quality Portal (NWQMC 2020). In addition, peer-reviewed publications may contain relevant site-specific data. The most crucial step to understanding contaminant mobility after careful evaluation of the published data is collection of field measurements. Typical parameters measured when collecting water samples include pH, temperature, conductivity, redox potential, dissolved oxygen (DO), and total dissolved solids (TDS). Among these parameters pH, DO, and redox potential are estimated by measuring the electropotential difference, where a reference solution or an electrode is used as a standard. Similarly, conductivity measurements are based on the current flow between two electrodes, which increases with dissolved ion concentrations. This provides a measure of the total amount of dissolved ions in solution (TDS). Measurements of such field parameters can either be made individually or using multiparameter sondes. Appropriate calibration techniques are included in manuals for specific probes or sondes, and for accurate measurements, careful cleaning of the electrodes and calibration for every parameter is recommended. Once at a site, it is crucial to allow probes to have enough time to equilibrate with water, before measurements are taken. Equilibration time is the time a sonde or any field instrument takes to stabilize by adapting to the dynamic field conditions for generating reliable measurements. For more information on field measurements and their importance, refer

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to the following studies (Bartram and Ballance 1996; Smith and Desvousges 2012; Rounds et al. 2015; USGS 2015). Proper sample collection procedures and field preservation of samples is also necessary to obtain high-quality results. If samples are not adequately preserved from the time of sampling to the time of analysis, errors in results can occur. The type of collection and bottle or bag used for transport much be selected to prevent contamination to a sample as follows: • Bottles used for collecting samples for cation and anion analysis are typically made of plastic while those used for organic carbon samples are made of glass. • All bottles are rinsed with dilute acids and distilled deionized water to remove contaminants prior to sample collection; however, only glass bottles are further heated @ 450–550  °C for an hour, to remove any residual organic contaminants. • It is customary to preserve water samples for cation analysis to a pH of 2 with nitric acid or other acids to avoid changes in chemical speciation that would otherwise affect concentration measurements. • Samples for anion analysis are typically not acidified as it would damage/denature the resins packed inside the ion chromatography columns. More detailed techniques and methods can be found in the USGS (2015). Evaluation of the water chemistry at a site begins with analysis of major cations, including calcium (Ca2+), sodium (Na+), magnesium (Mg2+), potassium (K+), and major anions, sulfate (SO42−), chloride (Cl−), carbonate (CO32−), and bicarbonate (HCO3−). Figure 4.1a, b is an example that uses hypothetical but realistic values to illustrate the distribution of these major ions within chemically distinct waters. Major ions can be plotted on a trilinear diagram called a Piper diagram (Fig. 4.1a), which plots the relative concentrations of each element in milliequivalent per liter (or kilogram) and allows potential groupings of similar water types to be identified. In addition, Piper diagrams can show the concentration of total dissolved solids (TDS) in each sample, which is shown by circle size in Fig. 4.1a. Stiff diagrams of these major elements also visually represent the major ion composition of a water sample; this can be useful in understanding the overall water types at a site (Fig. 4.1b) (Hem and Survey 1989; Piper 1944; Stiff Jr 1951). Stiff diagrams also show milliequivalents per liter (or kilogram) concentrations of major ions but show the data as a shape. In addition to the major ions that are typically plotted in Piper and Stiff diagrams, minor ions such as iron (Fe), aluminum (Al), manganese (Mn), and sulfur (S) can also be very important when studying mine sites. Concentrations of these minor element in water, rocks, and soils can be evaluated to identify potential background concentrations or spatial trends at a site. Isotopes of an element have different atomic masses. Isotopic signatures or ratios can provide information about the origin, age, temperature, source, extent of evaporation, infiltration, or reactions involving solids and water. For example, stable isotopes of water (Deuterium [2H], oxygen 17 [17O], and oxygen 18 [18O]) can indicate evaporation trends, temperature, or the source of the water (Langman et al. 2012). Similarly, radiogenic isotopes (234U, 238U) and their activity ratio (234U/238U) can help

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Fig. 4.1 (a) Piper diagram and (b) stiff diagram example

identify redox reactions that enhance U mobility within a mine site (Basu et  al. 2015). Tracking and identifying the contaminant source can be especially critical while trying to understand the toxicological impact of metals on human health. Isotopic ratios are also useful in acquiring historical information of water or water– solid interactions at a particular site, which can be critical to better understand metal mobility. 4.2.1.2  Geochemical Mechanisms Affecting the Mobility of Metals Various geochemical and physical processes affect metal mobility in the environment. For example, oxidation states of metals can directly enhance or impede their mobility and can alternate depending on the redox potential of the system. A metal can exist in several oxidation states in the environment; for example, uranium (U)

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can occur in IV, V, and VI oxidation states (Alessi et al. 2012; Ilton et  al. 2009; Kohler et al. 1996; Morss et al. 2006); arsenic (As) occurs in five different oxidation states, i.e., −I, 0, I, III, and V (Kim et  al. 2013; Neil et  al. 2014; Smedley and Kinniburgh 2002); Pb occurs in II and IV oxidation states (Lin and Valentine 2008; Liu et al. 2009; Lytle and Schock 2005); and Cr commonly occurs in III and VI oxidation states (Blowes et  al. 1997; Duckworth et  al. 2014; Icopini and Long 2002). Among these trace metals, U and Cr are mostly soluble and mobile in their most oxidized form, U(VI), or Cr(VI) (Duckworth et al. 2014; Blake et al. 2015), while Pb and As are most mobile in their reduced forms, Pb(II) or As(III) (Dixit and Hering 2003; Lin and Valentine 2008; Liu et  al. 2008b, 2009; Lytle and Schock 2005; Moldovan et al. 2003). However, under favorable conditions, even As(V) can be equally mobile and toxic as As(III) (Dixit and Hering 2003). Uranium, As, Pb, and Cr can also occur in the environment as solids, which include oxides, sulfides, carbonates, vanadates, silicates, or phosphates (Avasarala et  al. 2017; Dixit and Hering 2003; Giammar and Hering 2001; Kanematsu et al. 2014; Liu et al. 2009; Mandaliev et al. 2013; Olazabal et al. 1997; Orta et al. 2017; Richard and Bourg 1991; Singh et al. 2012; Troyer et al. 2014, 2016). Metals can also coexist in mixed minerals phases in soil/solids; this can magnify the negative health impacts compared to individual metals (Hettiarachchi et al. 2018; Zychowski et al. 2018). The formation (precipitation) and dissociation (dissolution) of solid mineral phases depend on chemical equilibrium, reaction kinetics, and water chemistry, including the system pH. A mineral phase may precipitate if the system is saturated with it; however, kinetic constraints may leave the system out of equilibrium. For example, if orthophosphate is added at pH ~7 into solutions containing 500 °C and then weighed to measure organic matter and carbonate content (Heiri et al. 2001). Total organic carbon (TOC) can be measured in several ways in soils and sediments. The USEPA documents these analytical methods in the following report (Schumacher 2002).

4.3  Analytical Techniques The development of advanced molecular, microscopic, and spectroscopic tools in the past decade has greatly increased the possibilities of studying interactions at the soil/rock–water interface and their long-term impact on the environment, both at a laboratory and a field scale. These advances have provided information about geochemical processes that directly or indirectly affect the fate, transport and transformation of various pollutants/contaminants. This section discusses several techniques that can be used in identifying and understanding some of the reaction pathways that affect metal mobility at the soil/rock–water interface.

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4.3.1  A  nalytical Techniques for Solids: Microscopy and Spectroscopy Surface microscopy and spectroscopy techniques provide invaluable information on crystallinity, occurrence, and oxidation states of different metals, which can be critical to understanding the geochemical cycling of metals. Several good reviews that describe the application of such advanced surface and bulk analytical techniques to better understand complex environmental systems are now available (Brown Jr and Sturchio 2002; D’amore et  al. 2005; Flores and Toca-Herrera 2009; Geesey et  al. 2002; Hochella Jr 1988; O’Day 1999). However, these reviews focus on targeted issues, unlike this chapter, which offers a broad overview on a range of analytical tools. 4.3.1.1  Elemental Analysis, Surface and Bulk Microtopography A combination of different spectroscopy and microscopy tools can be used to understand the elemental composition and micro-topography of minerals in ore samples collected from a study site. The elemental composition of solid ore or mineral phase is obtained using X-ray fluorescence (XRF). This technique uses x-rays to displace electron in the atomic orbital of elements within the sample that then release energy in the form of fluorescence, which is characteristic to a specific element. These elemental concentrations can either be reported as elements or as oxides, although the latter is only given for calculation purposes and should not be interpreted as mineralogy. Likewise, the elemental composition at the top 100-μm sample surface can be identified using energy-dispersive x-ray spectroscopy (EDS) in a scanning electron microscope (SEM). The SEM also offers high-resolution morphological

Fig. 4.3  SEM characterization of mine waste sample from northeastern Arizona. (a) BSE image of polished sample showing rock fragment with aggregates of a U–V phase (red arrows) associated with quartz, K-feldspar, and clay. (b) BSE image of dispersed mine waste sample showing micron-­ sized grains of a U–V phase on the surfaces of quartz and feldspar grains (Blake et al. 2015)

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and topographical information of mineral surfaces. Several studies have used SEM/ EDS to relate specific surface shape characteristics, chemical characteristics, and quantitative information to metal mobility (Fawcett et  al. 2015; Jamieson 2011; Stefaniak et al. 2009). A scanning electron micrograph of a mine waste sample containing quartz, clay, feldspar (KAlSi3O8), and carnotite (K2(UO2)2(VO4)2·3H2O) is illustrated in Fig.  4.3. These micrographs were captured in backscatter electron (BSE) mode, where the brightness/contrast of elements increases with an increase in atomic mass. This mode is especially useful for higher mass elements like U, Pb, and others that can otherwise be difficult to find, considering heterogeneity of natural samples and their potentially trace concentrations. In addition to capturing the localization of higher atomic masses using BSE mode, a SEM is capable of acquiring topographical, morphological, thickness and compositional information using its secondary electron, EDS, and auger electron modes. Other surface-based techniques include atomic force microscopy (AFM), a scanning force microscopy technique that can provide information regarding the mechanical properties and roughness of the sample surface through imaging and force measurement. AFM is a technique that uses atomic-level force to provide high-resolution imaging for direct visualization at the angstrom to micrometer scale (O’Day 1999). Additionally, AFM can also obtain any information related to surface area and size distribution of nanoparticles (Flores and Toca-Herrera 2009; McGuire et al. 2003; O’Day 1999; Wigginton et al. 2007). Transmission electron microscopy (TEM) and X-Ray Diffraction (XRD) can provide information on bulk characteristics, which include structural, crystalline, and compositional variation within a sample. TEM is a vacuum-based microscopy technique that differs from SEM; its capability to transmit electrons through the sample enables it to provide information on bulk characteristics of the sample, whereas the SEM is confined to the surface. However, TEMs require nanometer-­ scale samples for analysis; these are often obtained by using a focused ion beam (FIB), where thin sections are cut from a solid sample and mounted onto TEM grids. Transmission of electrons enables us to acquire very high-resolution images that are used to obtain information on physicochemical characteristics of submicron particles (Geesey et  al. 2002; Hochella Jr et  al. 2005; Wigginton et  al. 2007). Specifically, the electron energy loss spectroscopy (EELS), selected area electron diffraction (SAED), high-resolution energy dispersive spectroscopy (HR-EDS), and high-resolution transmission electron microscopy imaging (HR-TEM) functions in a TEM provide valuable information on the oxidation states, crystallinity, occurrence, morphology, and composition of submicron particles (Avasarala et al. 2019; Weber et al. 2016). For example, Fig. 4.4 shows a TEM image of mine waste samples collected from the Jackpile Mine, Laguna, NM, where HR-TEM imaging and EDS techniques were used to confirm the presence of submicron crystalline U-P-K minerals in the mine waste. XRD is a bulk analysis technique used to characterize crystalline solid phases, providing useful information about solid mineralogy and atom structure. However, an XRD is only sensitive to minerals that form at least 0.5–1% of the sample by weight. Therefore, XRD and electron microscopy are complementary tools that

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Fig. 4.4  TEM characterization of a mine waste sample from Jackpile mine, Laguna, New Mexico. (a) TEM image of submicron crystals of U-P-K minerals (red arrows) within the mine waste samples encapsulated in organic carbon. (b) EDS spectra of the submicron crystals, confirming associations between U, P, and K. (c) HR-TEM image of the submicron crystals that use patterned fringes to indicate crystallinity of U-P-K minerals (Avasarala et al. 2019)

allow us to investigate co-occurrence and interactions of metals within complex environmental samples that directly influence metal mobility. 4.3.1.2  S  olid-Phase Oxidation State and Molecular Coordination Analyses Several spectroscopic tools are available to characterize the surface and bulk speciation of metals in solid samples. • X-ray photoelectron spectroscopy (XPS) is a well-established surface analysis technique for determining the oxidation state of an element. XPS uses X-rays to emit photoelectrons from samples with a kinetic energy that is specific to the element’s binding energy and sensitive to its oxidation state (Hochella Jr 1988). Several investigations have used XPS to identify U, V, and As oxidation states in natural systems (Avasarala et al. 2017; Blake et al. 2017).

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• X-ray absorption spectroscopy (XAS) is another bulk technique that uses X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) tools to determine the oxidation state and molecular coordination of solid and aqueous samples. Several studies have used the XANES and EXAFS of XAS to study relevant geochemical processes (Avasarala et al. 2019; Bargar et al. 2008; Brown Jr and Sturchio 2002; Webb 2005). • Raman spectroscopy measures quantum state transitions related to molecular vibrations, relying on inelastic scattering from a laser source in the visible, near infrared, and near ultraviolet range. New developments in surface enhanced Raman spectroscopy (SERS) consist of doping gold or silver nanoparticles to solid samples to improve metal detection limits and has been employed for sensor applications (Muniz-Miranda and Sbrana 2001; Wang et al. 2006). Both XAS and Raman spectroscopy can also be used to analyze “wet” or “fully hydrated” samples.

4.3.2  Aqueous Analytical Techniques Numerous analytical options for measuring both cations and anions in water and rock/soil extracts exist. These include inductively coupled plasma-optical emission spectroscopy (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), ion chromatography (IC), and high-performance liquid chromatography (HPLC) coupled with ICP-MS. These analytical techniques provide a strong fundamental framework for aqueous characterization in geochemistry. ICP-OES, inductively coupled plasma-optical emission spectroscopy, measures elemental concentrations of major and minor cations using element specific-light wavelength emitted from atoms excited by the ICP (Olesik and Kinzer 2006). ICP-MS, inductively coupled plasma-mass spectrometry, measures major, minor, and trace cation concentrations based on the isotopic-mass-to-charge ratio of an element. Though both ICP-OES and ICP-MS measure cation concentrations, their applications vary depending on their detection limits. Specifically, an OES instrument has a lower detection limit of 10 μg/L or ppb and an upper detection limit in high mg/L. All cations that meet this concentration criteria can be measured using an ICP-OES. In contrast, ICP-MS has an instrument detection limit that ranges between 0.01 and 500 μg/L; however, these instrument detection limits are element specific. For example, the instrument detection limit of arsenic (As) in a Perkin Elmer 5300 DV is ~25 μg/L almost three times the detection limit of Cr, ~7 μg/L (Avasarala et  al. 2017). The analytical method used for analyzing the elemental concentrations can also affect the instrument detection limit. Previously, spectral/ mass interference, salt buildup, matrix effects, and sample introduction were some of the common challenges during sample analysis using an ICP (Evans and Giglio 1993; Todolí et al. 2002). However, significant improvements in software and hardware now allow one to rectify these issues during the analysis. For example, use of

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Dynamic Reaction Cells (DRC) and internal standards can significantly minimize any mass interferences or matrix effects in an ICP-MS. Samples prepared for analysis by ICP are typically preserved to a pH  × >0.2 μm) and nanoparticles (0.2> × >0.02 μm) into consideration (Fig. 4.5). It is important to understand that a one-step filtration with a 0.45-μm filter may not represent the true soluble elemental concentrations in a water sample. To further evaluate the association of metals and metalloids with mixtures of particles of various sizes in water, a sequential filtration technique should be adopted (Fig. 4.5). Even after filtration, accurate measurements of those fractions may only be possible if their respective fractions are dissolved. Therefore, to ensure dissolution of these fractions, acid digestions using aqua regia is necessary at every step. Recent developments in analytical chemistry methods facilitate application modules for separation of nanoparticles and quantifying their sizes (Auffan et  al. 2009; Lowry et  al. 2012). Ultrafiltration, which uses hydrostatic pressure to force water through different types of semipermeable membranes with different pore sizes, can be used to remove particles ranging in size from 5 to 20  nm (Huang et  al. 2016). Analyzing all of these particulate fractions in water provides information essential to obtaining a comprehensive understanding of elemental mobility in water (Kretzschmar et al. 1999).

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4.3.2.2  Digestion of Rocks and Soils for Aqueous Analysis Digestion of rocks and soils in different acid solutions provides valuable information about the mineralogic host phase of metals and metalloids. Typically, acid digestion of a rock or sediment follows a series of steps. The first step is often drying of the sample, followed by pulverization, homogenization, and sieving of the solid sample to the desired size. Both rocks and sediments are crushed and homogenized for acid digestions to overcome any heterogeneity effects. The desired quantity of dry sample is then weighed, and acid digested. Several acid solutions are commonly used to digest rocks; these include (1) aqua regia, (2) aqua regia +

Fig. 4.6  Examples of (a) Batch and (b) Column experimental (Avasarala et al. 2017) setups

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hydrofluoric acid to break down silica, (3) hydrogen peroxide + aqua regia to remove metals associated with the organic matter, (4) fusion of rock into a glass bead, (5) microwave digestions, and (6) four acid digestion (Hseu et al. 2002; EPA 1995, 1996, 2007; Sastre et al. 2002; Padfield and Gray 1971). The digestion process selected depends on the expected recoveries for the elements of interest (Sastre et al. 2002; Sun et al. 2001; Zheljazkov and Warman 2002). Following the digestion, the samples must be filtered using a 0.45-μm filter. The initial dry sample weight must be noted to be used in final concentration conversion from μg/L or mg/L to mg of element/Kg of rock or sediment. The filtered acid extracts from this process are then diluted accordingly and analyzed for their elemental concentrations using an ICP-OES and ICP-MS.

4.4  Laboratory Experiments The ability to identify specific mechanisms and processes affecting metal speciation and mobility is limited in field studies; therefore, laboratory experiments conducted under controlled conditions are important sources of information. Both batch and column experiments are performed to investigate relevant reactions of interest. Batch experiments can be setup in parallel or in series, depending on the needs of the proposed research, while column experiments need to be equipped for a flow-­ through setup (Fig. 4.6). Before starting an experiment, one needs to carefully evaluate and identify the best and the most simplified approach to address a research question (Rao et al. 2008). Such experiments enable us to investigate complex reactions happening at the soil–water interface. Following are a few scenarios where batch and column experiments can be used.

4.4.1  Batch Experiments Batch experiments are the simplest design for understanding reaction mechanisms at the solid–water interface. These experiments typically involve a reaction between a reagent of interest and solid samples (rock or soil, usually powdered for homogenization) collected from the field. Regent volumes vary but are usually in the range of 20–100 mL to enable the use of centrifuge tubes. Centrifuge tubes are convenient for separating solids from the solution while taking a sample. It is important to record the weight of the sample for use in dilution calculations, following the analysis. Replication of these experiments is recommended to account for any variability in the soil/rock sample matrix, experimental method, analytical method, and analytical instrument performance. Triplicate experiments can facilitate statistical analyses by reporting average and standard deviation values for each sample taken.

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Examples of reagents used for batch experiments using environmental solids include, but are not limited to: deionized water (to evaluate water soluble reactions), bicarbonate solution (to evaluate complexation/precipitation/ion exchange reactions), and acetic acid or ascorbic acid (for reaction under acidic conditions) (Rao et al. 2008; Blake et al. 2015). It is important to consider the chemical characteristics of each reactant used to anticipate possible reactions that could occur in the experiment. For example: • Organic acids can cause reduction and acid–base reactions depending on the selected pH and the acid formation constant. • Deionized water reacts with sediments to release the most easily mobile or soluble metals. For example, U and As released during deionized water reaction with solid samples represent the most mobile fraction (Blake et  al. 2017, 2019; Avasarala et al. 2017). • Bicarbonate is a very strong complexant that mobilizes metals from the water– soil interface. Typically, a 10-mM solution of bicarbonate with a pH of about 8.3 and which represents a common alkalinity of surface water is strong enough to complex and mobilize U from the solids (Blake et  al. 2017; Avasarala et  al. 2017, 2019). • Acetic acid and ascorbic acid solutions are useful for evaluating metal mobility at acidic pH, which is relevant for acidic water in a mine waste system. Sequential extractions are used to evaluate how elements are released after reaction with reagents of increasing strength and target different fractions of the same element bound differently within the solids. Tessier et al. (Tessier et al. 1979; Bacon and Davidson 2008; Rao et al. 2008; Yu et al. 2014) described in detail how sequential experiments can be useful in understanding mechanisms of metal mobility. It is important to carefully evaluate the reagents and the processes they undergo in reaction with the sediments before use, because different reagents target metals with different binding affinity depending on their strength. Results of sequential extractions can sometimes result in overinterpretation of the actual sequential reaction (Bacon and Davidson 2008). If possible, one must consider characterizing both solids and solutions before and after every step in the sequential reaction to determine changes in metal speciation and mobility. This could also act as an additional confirmation of the results or hypotheses without resulting in overinterpretation.

4.4.2  Column Experiments Column experiments provide information about the effects of flow, reaction, and transport on metal mobility and therefore are more representative of the natural environment. Along with possible reaction mechanisms observed during batch experiments, physical transport mechanisms such as advection, dispersion, and diffusion must also be considered in interpreting the results. In addition, other factors

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such as grain size, reagents, water quality, flowrate, column saturation, contact time, and kinetics also affect the mobility of metals (Avasarala et  al. 2017; Kim et  al. 2013; Li et al. 2009; Liu et al. 2008a, b; Qafoku et al. 2005). Figure 4.6b represents the setup of continuous-flow column experiments, where the reagent is introduced from the bottom to keep the column saturated and avoid channeling or preferential flow. This technique was used on mine waste samples acquired from Blue Gap/ Tachee, AZ, where the goal was to investigate the mechanisms affecting the transport of U and V (Avasarala et al. 2017). In subsurface/surface zones, solutions typically experience both saturated and unsaturated conditions due to preferential flow paths taken by the water. In account for this feature, column experiments can be conducted in either as continuous- or intermittent-flow conditions. In continuous-flow experiments, the sediments in columns are continuously reacted with the respective reagents and are almost always saturated (Avasarala et al. 2017). In contrast, intermittent-flow experiments alternate between wet (saturated) and dry conditions (unsaturated), affecting the reactivity of sediments/rocks in columns (Liu et al. 2008a). Column saturation can also depend on the direction of flow; if the flow is from the top, the water tends to choose the path of least resistance creating both unsaturated (Fig. 4.6b) and saturated zones inside the column, whereas when the flow is from the bottom, only saturated zones are present. Some important considerations for column experiments include potential channeling, wall effects, material preparation and packing, and the time and analytical costs of the large numbers of samples generated. Column experiments are valuable in characterizing the transport behavior of different metals/minerals in rock/sediments, because they are more representative of the environment. However, the information obtained must be complemented with reactive-transport modeling to identify the mechanism that predominantly affect the mobility and transport of different metals under given conditions. In the next section, the advantages of using reactive-transport and geochemical-thermodynamic models to understand metals transport are described.

4.5  Chemical Equilibrium and Reactive Transport Modeling Coupling experiments with chemical equilibrium and/or reactive transport modeling can provide additional and, in some cases, more robust interpretation of the results. Even though experiments offer a reasonable mechanistic understanding of metal mobility, the understanding is incomplete without the use of such models, considering the complexity and heterogeneity of environmental systems. Chemical equilibrium modeling uses thermodynamic constants, which include formation/dissociation constants of different aqueous complexes and minerals under relevant conditions to compute the behavior of chemical constituents in an aqueous solution (Blake et al. 2017; Dong and Brooks 2006; Parkhurst and Appelo 2013; Schecher and McAvoy 1992). Programs that are commonly used for chemical equilibrium

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modeling include PHREEQC, MINEQL, Geochemist’s Workbench, and GW Chart. PHREEQC is a computer program developed by the US Geological Survey that calculates the formation and distribution of various aqueous complexes and mineral precipitates based on the thermodynamic equilibrium of the system. Formation and distribution of such aqueous and solid species depend on the water chemical parameters, which include pH, alkalinity, and concentration (Parkhurst and Appelo 2013). PHREEQC can also be used to create simple 1D transport models to predict contaminant transport behavior. Like PHREEQC, MINEQL is also a chemical equilibrium model that is designed to work with low temperature (0–50  °C) and low-to-moderate ionic strength (5 μg/L, and (c) probability >10 μg/L, with a resolution of 30 m (Ayotte et al. 2012). These raster data layers were aggregated to the town level, with mean, maximum, and minimum arsenic values calculated for each town. Pearson’s correlation coefficients (r) between the birth outcomes (preterm birth and term LBW) and the arsenic values were calculated at both state and county

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a)

10.0 - 16.7 6.0 - 10.0 4.0 - 6.0

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3.5 - 4.0

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Belkna Sullivan

Merrimack

Carroll

Straffor

Rockingham Cheshire Hillsborough

Sullivan

Merrimack

Cheshire Hillsboroug h

Straffor

Rockingham 50 km

Fig. 7.6  New Hampshire town-level LBW rates for maternal age fresh fruits > bread > water. The geochemical studies on iodine concentration in food samples that were reported from different countries revealed that the concentration of iodine in the food type varies from country to country. Based on this observation, it is easy to suggest that factors such as the method used in food plantation, production, processing, and preservation as well as geological, ecological, and climatic factors are responsible for the variation. Sea fish and other food from the marine environment are often considered as the most important natural dietary source for iodine (Clugston and Hetzel 1994). Johnson (2003) suggested the consumption of tinned sea fish (e.g., sardines) in iodine-deficient areas as a strategy for reducing Iodine Deficiency Disorders (IDDs). The relative mean contributions from food, air, and water per day to iodine intake are 156 μg, 0.3 μg, and 12 μg, respectively, of which 5–10 μg of iodine is expected to come from drinking 1.5–2 L of water per day (Johnson 2003). In general, daily iodine contribution from water intake (drinking water) is estimated to be low compared to other dietary sources. However, Fordyce (2003) explained that drinking from groundwater that is highly enriched in iodine can give more than 20% of the recommended daily allowable intake (RDAI) of iodine. For example, in Denmark,

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25% of the iodine in an average meal is from drinking water and beverages such as coffee and tea (Rasmussen et al. 2000). Also, studies conducted in Denmark and Argentina also revealed that drinking water could be a major contributor to dietary iodine (Watts et al. 2010; Voutchkova et al. 2014). In addition, human exposure to excessive iodine intake from drinking water sources was reported in some provinces of China (Shen et al. 2011). Other food additives such as emulsifiers, stabilizers, and thickeners containing iodine also contribute minute quantity (about 1 μg/day) to dietary iodine (Risher and Keith 2009). Also, the use of iodophor cleansers of milk cans and, in some cases, the use of iodate as bread conditioners contribute to dietary iodine (Leung et al. 2012; Johnson 2008; Risher and Keith 2009). Other sources of iodine intake are alternative medicines and nutritional supplements, which can approach toxic levels depending on the specific iodine content and dosage (Risher et al. 2004). For instance, several studies revealed that excess iodine can be released from antithyroid drugs, especially amiodarone, which contains 75 mg of iodine (in one 200 mg tablet) with a long half-life of approximately 100 days (Roti and Uberti 2004; Leung and Braverman 2014). Iodized salt can also be regarded as a dietary source of iodine. The Universal Salt Iodization (USI) program launched by the World Health Organization (WHO), United Nations Children’s Fund (UNICEF), and International Council for Control of Iodine Deficiency Disorder (ICCIDD) enabled all salt used in agriculture, food processing, catering, and household to be iodized. The main recommendation was that at the factory/production site, a kg of salt should contain about 20–40 mg of iodine concentration (WHO, UNICEF, ICCIDD 1996). Meanwhile, this standard was set based on the fact that 20% of iodine content in salt at production site will be lost before getting to household and another 20% or more will be lost during various food cooking methods that include frying, boiling, and grilling (WHO, UNICEF, ICCIDD 1996). Worldwide, 86% of households are currently consuming iodized salt (UNICEF State of the World’s Children 2017). This program has been found successful in the last three decades in eradicating and reducing the global health dilemma caused by iodine deficiency in some parts of the World.

17.4.1  Recommended Daily Iodine Intake by Age Group The daily consumption of iodine as recommended by WHO (2007) is 90  μg for infants and children up to 5  years, 120  μg for children between the age 6 and 12 years, 150 μg for children over 12 years and adults, and 250 μg for pregnant and lactating women (see Table 17.2). A teaspoon of iodine (an equivalent of 5 g) is sufficient to meet the lifetime needs of a person with a life span of 70 years (Dhaar and Robbani 2008).

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Table 17.2  RDAI of iodine and summary of the possible adverse health effect of its deficiency on different age groups (Laurberg et  al. 2000; WHO/UNICEF/ICCIDD 2007; Delange and Hetzel 2008)

Age group Fetus Pregnant women and lactating mothers Neonatal to teens Children to teenagers Adults

All age group

Age (in years) 0–birth

Daily recommended iodine intake (μg/day) 90

Adult

250

0–5 years

90

6–12 years

120

>12 years and above

150

All ages

Possible adverse health effect of iodine for different age group Abortion, stillbirth, congenital anomalies, perinatal mortality, and transient hypothyroidism The result in the fetus is the same as in pregnant women (Eastman and Zimmermann 2017)

Infant mortality, endemic cretinism, and impaired mental function Delayed physical development and impaired mental function Iodine-induced hyperthyroidism, overall moderate-to-severe iodine deficiency, causes subtle but widespread adverse effects in a population secondary to hypothyroidism, including decreased educability, apathy, and reduced work productivity, resulting in impaired social and economic development Increased susceptibility of the thyroid gland to damage and thyroid cancer from iodine radioisotopes (e.g., from radioactive fall-out)

17.5  Iodine Health Impacts in Humans 17.5.1  Health Benefits Iodine is an essential element required in minute quantity in the human body for the biosynthesis of the thyroid hormones, the thyroxine, T4 (molecular formulae C15H12I3NO4), and triiodothyronine, T3 (molecular formulae C15H11I4NO4) (Knez and Graham 2013). T3 acts as a regulator for growth and development by increasing energy production and inhibiting the synthesis of various proteins (Hetzel and Wellby 1997; Zimmermann 2011; Combs Jr 2013). In the thyroid gland, iodine is of concern in normalizing human body growth, maturation and development, cell and tissue growth, and body metabolism (Hetzel 1989). Sufficient level of iodine in the mammary gland plays an important role in fetal and neonatal development during breastfeeding (Ahad and Ganie 2010). This explains why pregnant and lactating women require more iodine than other adults (Delange 2004). Iodine controls the estrogen effect on breast tissues and prevents radioactivity effects (Knez and Graham 2013). A study conducted on female rats proved that iodine normalizes elevated adrenal corticosteroid hormone secretion related to stress (Nolan et al. 2000).

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17.5.2  Adverse Health Effects The thyroid gland maintains normal thyroid function with some modification in its function, depending on the amount of iodine intake (Koukkou et  al. 2017). This process is called autoregulatory, and it helps to regulate the iodine metabolism independent of the thyroid-stimulating hormones (TSHs) (Koukkou et  al. 2017). Moreover, a significant increase or decrease in the daily RDAI of iodine could cause an adverse effect on humans (see Table 17.2). Eastman and Zimmermann (2017) and other several authors reported that both deficiency and excessive iodine intake could increase the risk of thyroid diseases (Elnour et al. 2000; Zhao et al. 2000; Luo et al. 2014; Sun et al. 2014; Ferrari et al. 2017).

17.5.3  Iodine Deficiency Iodine deficiency affects approximately two billion people worldwide (Stephaniel 2015), and it is responsible for almost all-preventable mental retardation, which puts about one-third of the global population at risk (Zimmermann 2008, 2009). The Acronym “IDD” is a collective name coined out to represent all health issues caused by iodine deficiency. Several authors including Rastogi and Mathers (2002), WHO (2004), Utiger (2006), and De Benoist et al. (2008) highlighted health issues such as mental retardation, developmental disability, cretinism, reproductive failure, and goiter and congenital hypothyroidism as a consequence of iodine deficiency on all age groups. Endemic goiter is the most obvious manifestation of iodine deficiency, while brain damage is its most devastating consequence that results in mental retardation in children (Li and Eastman 2012). Reduction in blood thyroid hormones during the gestation period is associated with a greater incidence of abortions, stillbirth, and congenital abnormalities (Delange and Hetzel 2019). According to Zimmermann (2008), iodine deficiency is severe in pregnant women and young children because it could result in miscarriages, while a moderate deficiency can impede stages of fetal growth, which results in physical and mental retardations, as well as a severe and irreversible condition known as cretinism. Endemic cretinism is the extreme clinical manifestation of severe hypothyroidism during fetal, neonatal, and childhood stages of development (Kapil 2007). This author explained that cretinism is characterized by severe and irreversible mental retardation, short stature, deaf-mutism, spastic diplegia, and squints (Kapil 2007). The author further explained that two types of cretinism exist in severe endemic areas and there is neurological cretinism which occurs when hypothyroidism is confined to the in utero or neonatal stages. There is also myxedematous cretinism, and it is associated with mental retardation alongside myxedema and dwarfism. During pregnancy, iodine deficiency in mother, especially during the first trimester, consequently results in an insufficient supply of thyroid hormones to fetus brain, and this could lead to impaired central nervous system development and mental retardation (Delange and Hetzel 2019; Hay et al. 2019). This mental retardation extends

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from fetus up to the ages of 2 years, around which brain has achieved an adult weight (Delange and Hetzel 2019). Mild iodine deficiency during gestation could cause gestational iodine deficiency processing disorder that is associated more with reduced speed of neurotransmitting, which could result in reduced working memory capacity, attention, and response inhibition (Hay et al. 2019). These authors also pointed out that gestational iodine deficiency disorder could also occur together with other developmental disorders such as autism spectrum disorder (ASD), Attention deficit hyperactivity disorder (ADHD), language and reading disorders, learning disabilities, and dyslexia as well as reduced performance on verbal intelligent quotient (IQ) subsets. In areas having moderate to severe iodine deficiency, children from the age of 2 months up to 15 years can lose approximately 13.5 IQ points (Bleichrodt and Born 1994; Qian et al. 2005). A study showed that prolonged iodine deficiency in children is responsible for slow learning that results in low scores on motivation test (Tiwari et al. 1996). Another study revealed that iodine deficiency associated with low thyroxine level and high TSH could lead to attention-deficit hyperactivity disorder in children from a severely iodine-deficient area (Vermiglio et al. 2004). Iodine deficiency results in hypothyroidism with low levels of thyroid hormones (T3 and T4) and elevation of TSH, thyroglobulin, and reverse T3 test levels (Meletis 2011). Congenital hypothyroidism is a thyroid hormone deficiency at birth caused by a problem with thyroid gland development or a disorder of thyroid hormone synthesis that results in primary hypothyroidism, while a decrease in TSH results in secondary hypothyroidism (Rastogi and LaFranchi 2010). Studies conducted by Selva et al. (2005) and Kempers et al. (2006) revealed that infants with severe congenital hypothyroidism are at greater risk of developmental delay. Mild and moderate iodine deficiency causes multifocal autonomous growth of thyroid, which results in thyrotoxicosis (Chung 2014). Severe iodine deficiency causes hypothyroidism that results in impaired somatic growth and motor development in children (Chung 2014), while chronic iodine deficiency leads to goiter development when the total thyroid iodine content is depleted (Li and Eastman 2012). Some studies have demonstrated that severe iodine deficiency in breast tissue plays a role in breast cancer development (Stoddard II et  al. 2008). The epidemiological study conducted by Cann et al. (2007) revealed that there is an association between iodine deficiency and prostate cancer risks.

17.5.4  E  lements, Vitamins, and Chemical Compounds/ Substance that Exacerbate the Effect of Iodine Deficiency Some elements and vitamins are important for the utilization of iodine in thyroid hormone synthesis. Conversely, deficiencies of these elements, especially selenium (Se) and iron (Fe), as well as vitamin A, could exacerbate health conditions caused by iodine deficiency. Also, toxic elements and goitrogenic compounds may interfere with iodine intake and reduce iodine bioavailability in the thyroid gland.

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Nordberg and Cherian (2013) explained that Se is required in the thyroid gland for the deiodination activity of T4 and T3, which helps to reverse and regulate the concentration of T3. These authors further explained that Se helps in protecting the thyroid gland from peroxides that are produced during the formation of T4 and T3. For instance, Se and thyroid cells produce two enzymes called glutathione peroxidase and thioredoxin, which act as antioxidants and fight off the free radicals that are produced during the formation of T4 hormones (Thyroid Advisor 2017). Consequently, Se deficiency may impair T4 conversion (Lindh 2013) and can exacerbate some detrimental effects of iodine deficiency. An experiment conducted by Voudouri et al. (2003) on sheep’s thyroid and brain showed that sensitive interaction exists between Se and iodine deficiency. A case study from Western China and Central Africa revealed that the deficiency of both iodine and Se was associated with increased risk for thyroid dysfunction and other IDD’s issues (Wu et al. 1995). In addition, a study conducted by Denisova et al. (2010) showed that Se in thyroid tissue correlates positively with the level of zinc (Zn) and calcium (Ca). In their study, the substitution and combination of Se with other nonessential elements such as bromine (Br), mercury (Hg), and cobalt (Co) increase the severity of Se deficiency and consequently affect thyroid metabolism, hormonal synthesis, and lower cell resistant to oxidant stress. Michael (2013) affirmed that deficiency of Fe, Se, Zn, and vitamins A and D could negatively affect thyroid hormone. Deficiency of Zn and Fe can also exacerbate the effects of iodine deficiency (Zimmerman and Kőhle 2002; Biebinger et al. 2002). Experiments conducted on animals and humans showed that Fe deficiency can weaken thyroid hormone synthesis by reducing the activity of the heme-­ dependent thyroid peroxidase, resulting in thyroid dysfunction (Mohammad et al. 2006). Zn is required in the thyroid gland for the conversion of the inactive thyroid hormone, T4, into the active diiodothyronine, T3 (Progressive Health 2017). Conversely, Zn deficiency prevents liver type 5′-deiodinase and lower plasma concentration of T3 as revealed in a study conducted by Nordberg and Cherian (2013). The study further revealed that some humans who are Zn deficient also have low plasma concentration of T3 and confirmed the possibility of hypothyroid in human deficient in Zn. In addition, Ambooken et al. (2013) and other researchers suggested that Zn deficiency could result in subclinical hypothyroidism. Copper (Cu) is essential for the proper functioning of the thyroid glands and metabolic processes of other organs but too much or too little of Cu may lead to the malfunctioning of the thyroid gland (American Thyroid Association, ATA 2012). This could later result in hormonal imbalance, which consequently results in a shortage of the hormone, leading to hypothyroidism, or excess of the hormone, leading to hyperthyroidism (ATA 2012). The combined effect of Cu and Hg toxicity can lower thyroid activity; also when Cu lowers potassium (K), a decrease in thyroid activity is likely to occur (ATA 2012). High magnesium (Mg) and Ca can result in a decrease in thyroid activities (ATA 2012). Furthermore, Mg deficiency results in thyroid vascularization (Monocayo and Monocayo 2015). A relationship has been established in the dietary intake of Ca

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and iodine, and the deficiency of Ca can worsen iodine deficiency, which possibly contributes to goiter development (Italo and George. 1936). Iodine interference with Zn and Ca increases sodium (Na) amount on a hair test, and this was suggested to influence the symptoms of thyroid hyperactivity (ATA 2012). Osansky (2013) mentioned that deficiency of Manganese (Mn) can contribute to the hypothyroid condition and excessive intake could cause a problem with thyroid hormone production. Soldin and Aschner (2007) explained that excessive exposure to Mn may lead to adverse neurodevelopmental outcomes due to the disruption of thyroid homeostasis via the loss of dopaminergic control of TSH regulation of thyroid hormones, which in turn may alter thyroid hormone levels. Furthermore, a study conducted by Luca et al. (2017) on rats showed that low nontoxic dose of molybdenum (Mo) impairs iodine uptake from thyroid and accelerates thyroid abnormalities induced by goitrogenic diet. Cadmium (Cd) interference with other enzyme systems often causes symptoms of fatigue and lowered thyroid activity (ATA 2012). A study conducted by Yu (2017) revealed a case of hypothyroidism that is associated with Co toxicity. An experimental study conducted on rats revealed that vanadium (V) deficiency can increase thyroid weight and decrease thyroid peroxidase (TPO) activity (Kohlmeier 2003). Toxic elements such as lead (Pb), arsenic (As), and cadmium (Cd) can worsen the effect of iodine deficiency or have a direct physiological effect on the thyroid gland by inhibiting iodine uptake by the thyroid gland. Pb is known to have an adverse effect on many organ systems, and several authors among whom are Dundar et al. (2006); Klein et al. (1998); and Singh et al. (2000) reported that Pb could possibly affect the thyroid gland. The interference of Pb with Ca metabolism can result in thyroid imbalance (ATA 2012). Recep et al. (2010) noted that high levels of Pb in the blood might have a physiological effect on the thyroid gland. Authors such as Arthur et al. (1993), Hotz et al. (1997), and Sulchan (2007) affirmed that Pb can act as an antiblocking agent that inhibits iodine utilization by the thyroid gland. In addition, excessive exposure to As can affect thyroid health possibly by affecting the thyroid hormone receptors (Ciarrocca et al. 2012). According to Jancic and Stosic (2014), thyroid conditions that include colloid cystic goiter are associated with chronic Cd toxicity. Several researchers including Pearce et  al. (2013), Fuge (2013), and Hurrell (1997) noted the combined effects of goitrogens and iodine on the thyroid gland. Goitrogens are chemical substances found in goitrogenic foods like cassava, millets, brussel sprouts, kohlrabi, turnips, rutabaga, radishes, cabbage, kale, cauliflower, and a few vegetables (Das et al. 2005). According to Hurrell (1997), the major goitrogen in plant foods is sulfur-containing glucosides and there are two major types, those that yield thiocyanates that block the transfer of iodine into the thyroid gland and those that yield oxazolidine-2-thiones that inhibit the iodization of thyroglobulin and coupling of the iodotyrosine residues (Hurrell 1997). These substances affect the secretion of thyroid hormones by affecting the uptake of iodine in the thyroid gland and causing the gland to release TSH, which promotes the enlargement of the thyroid gland and consequently causes goiter (Bender 2009; Das et al. 2005; Sulchan 2007). Flavonoids are other goitrogen compounds found in staple food like millet,

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and these compounds inhibit the activity of the TPO enzyme that catalyzes important step in thyroid hormone synthesis (Pearce et al. 2013). A study conducted by Delange et al. (1982) in Zaria revealed the goitrogen effect of cassava on the thyroid gland and that the cause was related to cassava intake. In addition, studies conducted in Congo, Sudan, and Ethiopia showed goitrogen in cassava and millet as a contributing factor to goiter prevalence in the area (Abuye et al. 2007; Elnour et al. 2000).

17.5.5  Iodine Excess (Toxicity) Andersson et al. (2012) reported that the worldwide survey of the median urinary iodine concentration (UIC) conducted in 2011 revealed that 11 countries in the world have a health problem related to excessive iodine. The primary effect of excessive intake of iodine is on the thyroid gland and the regulation of thyroid hormone production and secretion (Agency for Toxic Substances and Diseases Registry (ATSDR) 2018). Its effect on the thyroid gland results in health conditions that include hyperthyroidism and hypothyroidism both of which may involve inflammatory features such as thyroiditis (Risher and Keith 2009). The secondary adverse effect on the pituitary and adrenal glands occurs due to thyroid gland dysfunctions (ATSDR 2018). Exposure to a high dose of iodine could result in a decrease in intrathyroidal deiodinase activity, which may contribute to a reduction in thyroid hormone synthesis (Leung and Braverman 2014). In 1948, the effect of excessive iodine intake was initially documented by Wolff and Chaikoff at the University of California Berkeley, USA, when they observed a transient reduction (lasting ~24  h) in the synthesis of thyroid hormones in rats exposed to high amounts of I− administered intraperitoneally (Leung and Braverman 2014). This effect is known as the Wolff-Chaikoff effect, and it describes the actions that iodine excess exerted in several levels of thyroid metabolism involving iodine uptake and organification, intermediate steps of metabolism, and presumably proteolysis and hormone release (Koukkou et  al. 2017). Although several clinical and epidemiological studies have reported the actions of iodine excess on the thyroid function, most researchers noted that the mechanism involved in the inhibition of organification is not clear. However, few researchers speculated that the mechanism likely depends on the intrathyroidal I− concentration, which has an inhibitory effect on TPO or some other enzymes (Koukkou et al. 2017). As demonstrated by Wolff et al. (1949) cited in Chung (2014), the Wolff-Chaikoff effect occurs when an acute I− excess rapidly decreases the synthesis of the thyroid hormone in the gland. These authors further demonstrated that normal individuals escape from the acute Wolff-Chaikoff effect after a few days without a significant change in the circulation of the hormone levels. This phenomenon is termed ‘escape from the Wolff-Chaikoff effect’ or ‘adaptation to the Wolff-Chaikoff effect’ (Wolff et al. 1949 cited in Chung 2014). Escape was said to be due to downregulation of the sodium/iodide symporter (NIS) on the basolateral membrane and the iodide transporter in the gland, which result in a decrease in the intrathyroidal iodine,

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modulation of the influx of iodine entering the thyroid gland, and resumption to normal synthesis of thyroid hormone (Wolff and Chaikoff 1948 cited in Chung 2014). Furthermore, chronic/acute excess of I− after several weeks of exposure can decrease the circulation of T4 and T3 levels and induces hypothyroidism in an individual having an underlying thyroid disorder, perhaps mild, autoimmune thyroid disease such as Hashimoto’s thyroiditis (Markou et al. 2001). This individual fails to escape the acute Wolff-Chaikoff effect, and this failure is also more likely during fetal development, a period when the hypothalamic-pituitary-thyroid axis is still immature and during neonatal life (Leung and Braverman 2014). Mothers exposed to a high level of iodine during pregnancy could possibly escape the Wolff-Chaikoff effect, but the fetal thyroid gland does not have the ability to escape from the acute effect until 36 weeks of gestation (Risher and Keith 2009; Bartalena et al. 2001). Hence, this exposure in fetal through mother can lead to transient hypothyroidism and congenital goiter (Nishiyama et al. 2004; ATSDR 2018). In the early 1800s, the Jod-Basedow effect (Jod means iodine in German word) was used to describe an iodine-induced hyperthyroidism condition when thyrotoxicosis developed in individuals with underlying goiter whose diet was supplemented with I− (Chung 2014; Leung and Braverman 2014). This effect established a status of excessive thyroid hormone synthesis and release that resulted in iodine-induced hyperthyroidism in susceptible individuals after exposure to a high level of iodine (Chung 2014). An epidemiological study conducted in endemic and iodine deficiency areas of Tasmania revealed two to four times increase in hyperthyroidism cases within a few months of introducing I− supplement in the diet (Risher and Keith 2009). Individuals that are most susceptible to iodine-induced hyperthyroidism include people who have a previous history of iodine deficiency, goiter, or thyroid disorder, including nodular goiter or Graves’ disease (Risher and Keith 2009). Graves’ disease is described as a small goiter, thyrotoxicosis, and/or hypothyroidism and chronic autoimmune thyroiditis or Hashimoto that is expressed as goiter due to lymphocytic infiltration and/or hypothyroidism (Ogbera and Kuku 2011). Grave diseases can also occur as diffuse and nodular or multinodular goiter, which can be described as toxic or nontoxic (Ogbera and Kuku 2011). High iodine intake is associated with autoimmune thyroid disease (Laurberg et  al. 2010). A report by Koutras (1996) revealed that 30% of a group of goiter patients developed thyroid autoimmunity several weeks after receiving 150 or 300 μg iodine per day. Autoimmune thyroiditis often developed in some individuals who are susceptible to thyroid disorder (ATSDR 2018). It is an inflammation of the thyroid gland, which can lead to fibrosis of the gland as well as hypothyroidism and hyperthyroidism when large doses of iodine are ingested (ATSDR 2018). A high dose of iodine is also linked to the incidence of thyroid cancer including papillary and follicular thyroid cancer (Koukkou et al. 2017; Risher and Keith 2009; Chung 2014). Although epidemiological evidence supporting this statement is unclear, other environmental factors may also be the cause (Koukkou et al. 2017). However, the incidence of papillary thyroid cancer was reported to be higher in geographic areas with high dietary iodine content, whereas that of follicular thyroid cancer was high in endemic goiter areas (Risher and Keith 2009).

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17.6  Iodine Mechanisms in Human Body 17.6.1  A  bsorption, Distribution, and Elimination of Iodine in Human Body Iodine incorporated in food is completely absorbed in the gastrointestinal tract (Risher et  al. 2004), whereas, iodine compounds such as 12 and IO3− may likely undergo reduction to I− before it is absorbed in the small intestine and absorption may not be complete (Risher et al. 2004). Also, iodine in organic form is converted into I− before it is absorbed (Cavalieri 1997). When humans get exposed to I2 vapor via inhalation, I2 is completely absorbed in the respiratory tract within a half time of 10 min, after which a larger percentage of the iodine is transferred to the gastrointestinal tract (Risher et al. 2004). Similarly, when CH3I vapor is inhaled, approximately 70% of it will be absorbed as I− in the respiratory tract within half time of 5 seconds. An investigation conducted on animal (monkeys) revealed the rapid absorption of I− in the respiratory tract when particulate aerosols of radioiodine in the form of sodium iodide were inhaled (Thieblemont et al. 1965; Perrault et al. 1967 cited in Risher et al. 2004). When soluble doses of I− salts (NaI and KI) are ingested, there is approximately 100% absorption in the gastrointestinal tract (Risher et al. 2004). This statement is supported by a study conducted on 20 euthyroid adults, which revealed urinary iodine excretion of 80–90% of the daily intake of 1 mg of potassium iodide per day when ingested for 13 weeks (Fisher et al. 1965 cited in Risher and Keith 2009). Risher et al. (2004) highlighted several experimental studies that were conducted on humans and animals, which revealed dermal absorption of iodine. One of the studies that supported the statement revealed an increase in urinary iodine excretion after povidone iodine was applied as part of a surgical scrubs to hand and arms (Risher et al. 2004). The concentration of iodine in a normal human being is approximated to 15–20 mg, out of which 70–80% is found in the thyroid gland (WHO 1996). The remaining portion is found in other body tissues such as mammary gland, eye, gastric, mucosa cervix, and salivary glands (Risher et  al. 2004; Porterfield 2001). Meanwhile the function of iodine is defined in the thyroid gland and mammary gland, but its function is not well understood in other tissue (Dunn 1998). The thyroid gland secretes 80 μg of iodine per day in the form of T3 and T4, out of which 40 μg appears in the extracellular fluid (ECF) per day (Ahad and Ganie 2010). During the metabolism of T3 and T4 in the liver, 60 μg of iodine is released into the ECF and 20 μg is released into the bile (Ahad and Ganie 2010). More than 97% of the absorbed iodine is excreted primarily in urine, and 1–2% is eliminated in feces (Hays 2001). The rest is excreted also in breast milk, exhaled air, sweat, and tears (Cavalieri 1997).

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17.6.2  I odine Uptake by the Thyroid Gland and Thyroid Hormone Synthesis The uptake of the iodine and the biosynthesis of thyroid hormones involve various stages, which are highlighted below. All the major stages involved in thyroid hormone synthesis and release are stimulated by the pituitary hormone, which is often referred to as TSH (Risher et al. 2004). Iodine trapping (a): This stage begins with the uptake of iodine from the capillary into the follicular cell by an active transport system (Ahad and Ganie 2010). This occurs against chemical and electrical gradients by Na/I symporter protein (NIS) found in the basolateral membrane of the follicular cell. The energy required in the first step is called ATPase-dependent Na+/K pump (Khurana 2006). Afterward, thyroglobulin (Tg) is synthesized and secreted and this occurs by another independent process within the follicular cell (Ahad and Ganie 2010). The synthesis begins on the rough endoplasmic reticulum as peptide units (Ahad and Ganie 2010). The Tg molecules contain about 140 tyrosine residues that serve as a substrate for the synthesis of thyroid hormones (Khurana 2006; Pal 2007). Tg within the small vesicles moves toward the apical surface of the plasma membrane and later released into the follicular lumen (Ahad and Ganie 2010; Risher et al. 2004). Iodine efflux (b): During this stage, I− is immediately oxidized to iodine when I− within the follicular cell moves toward the apical surface of the plasma membrane and enters into the follicular lumen (Ahad and Ganie 2010; Khurana 2006; Pal 2007; Risher et al. 2004). This movement is controlled by pendrin, a sodium independent iodide/chloride transporter (Ahad and Ganie 2010). Iodination (c): At this stage, the iodination of the tyrosine residues present within the Tg molecules takes place at the follicular cell-lumen interface (Risher et al. 2004; Ahad and Ganie 2010). The iodination first occurs at position 3 to form monoiodotyrosine, MIT, and at position 5 to form diiodotyrosine, DIT (Risher et al. 2004; Ahad and Ganie 2010). Coupling (d): The iodination process is followed by a coupling reaction that produces T4 and T3 hormone, and the reaction is catalyzed by TPO (Patrick 2008). The coupling of two molecules of DIT produces T4, and coupling of one molecule of MIT and one molecule of DIT produces T3 (Risher et al. 2004; Khurana 2006; Pal 2007). The amount of T4 and T3 produced depends in part on the availability of I−, and the ratio of T4:T3 in the thyroid is 15:1 (Risher et al. 2004). A low level of iodine will result in a decrease in the T4/T3 synthesis ratio (Taurog 1996 cited in Risher et al. 2004). T3 and T4 produced are then stored inside the thyroid follicles as colloids for several months and can meet the body requirement for approximately 3 months (Khurana 2006; Pal 2007). Colloid resorption (e): The colloid later undergoes endocytosis, which is facilitated by the Tg receptor called megalin that is present on the apical membrane (Ahad and Ganie 2010). Afterward, the colloid enters the cytoplasm in the form of col-

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loid droplets and moves toward the basal membrane (Ahad and Ganie 2010). The colloid droplets then fuse with lysosome vesicle, which contains proteolytic enzymes known as proteases (Ahad and Ganie 2010; Risher et al. 2004). Proteolysis (f): During this stage, the proteases in the lysosome help break down the Tg molecule into constituent amino acid residues including T4, T3, DIT, and MIT. T4 and T3 diffuse via the basal surface into the bloodstream; meanwhile, the MIT and DIT residues are retained in the cell (Risher et al. 2004). Deiodination(g): The MIT and DIT get rapidly deiodinated by enzyme deiodinase (Ahad and Ganie 2010), and I− is recycled into the follicular lumen where it is incorporated into Tg (Risher et al. 2004). This mechanism helps retrieve I− for recycling along with tyrosine (Khurana 2006; Pal 2007). Then, I− released is reused by the thyroid or release into the blood (Cavalieri 1997). Deiodination of T3and T4(h): Ninety-nine percent of T3 and T4 circulate in bound form in the bloodstream, and less than 1% circulates in an unbound form (Risher and Keith 2009; Ahad and Ganie 2010). The bounding proteins include thyroxine-­ binding globulin, TBG, thyroxine-binding prealbumin, TBPA, and thyroxine-­ binding albumin, TBA (Ahad and Ganie 2010). The binding hormones serve as a reservoir and also help to prevent urinary loss of hormones (Ahad and Ganie 2010). Meanwhile, the unbound hormones are biologically active, of which T3 is the most active hormone and about 80% of T3 in the bloodstream is derived from deiodination of T4 (Risher et  al. 2004; Khurana 2006) in the liver and kidney under the action of the selenium-dependent enzyme 5-deiodinase (Hurrell 1997). Thyroid secretion (i–j): The thyroid secretion is controlled by the pituitary gland through TSH, which operates on a feedback mechanism that turned on T4 levels in the blood (Ahad and Ganie 2010). A decrease in T4 level stimulates the ­pituitary to increase its TSH secretion, which in turn stimulates the thyroid gland to release T4 in circulation to maintain normal levels of the hormone in the blood (Pal 2007).

17.7  A  nalytical Methods Used in Quantifying Iodine Concentration in Environmental and Biomonitoring Samples Risher and Keith (2009) highlighted a number of analytical methods that are effective in the determination of iodine concentration in air, water, soils, sediments, pharmaceuticals, and foods. The instruments used include Instrumental Neutron Activation Analysis (INAA) with a gamma-ray detector, Isotope Dilution Mass Spectrometry (IDMS), Ion Chromatography (IC), Colorimetry, Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), High-Performance Liquid Chromatography (HPLC) with ultraviolent, arsenic–cerium catalytic spectrometry, and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Below is a summary of the analytical method discussed by Risher and Keith (2009).

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17.7.1  Environmental Samples 17.7.1.1  Air The concentration of iodine can be measured in ambient air by passing a known volume of air through a multistage filter assembly in order to collect and separate various iodine species and compounds present in the air (Risher and Keith 2009). To extract the particulate iodine fraction present in the air, filters are extracted in a heated sodium hydroxide/sodium sulfate solution, which contains iodine isotope 129 as an internal standard (Risher and Keith 2009). Afterward, silver nitrate is added to precipitate iodine as silver iodide (AgI), which is dissolved in aqueous ammonia after which it is analyzed using IDMS (Risher and Keith 2009). For an average air volume of 70 m3, about 97–99% of iodine is recovered with a sample detection limit of 0.02–0.002 ng/m3 (Gäbler and Heumann 1993). 17.7.1.2  Drinking Water and Seawater To estimate the concentration of total iodine in drinking water, potassium carbonate is added to water samples, and the sample is centrifuged to remove precipitated alkaline earth metals (Risher and Keith 2009), after which nitric acid, sodium chloride, ammonium ferric sulfate, and potassium sulfur cyanide are added before spectrophotometry analysis is carried out (Risher and Keith 2009). By using the detection limit of 0.2 μg/L, 90–108% of iodine is recovered from the sample (Moxon 1984). Iodine in the seawater sample is first precipitated with silver nitrate, and then precipitate is dissolved in acetic acid that is saturated with bromine, which is followed by filtration (Risher and Keith 2009). For spectrophotometric analysis, the volume of the filtrate is reduced and then reacted with starch solution and cadmium iodide (Risher and Keith 2009). A sample detection limit of 0.025 μg/L yields 99% recovery estimated at 10 μg of iodine per liter (Tsunogai 1971). 17.7.1.3  Soil, Sediment, and Rock Soil samples are first dried, sieved (7 mm diameter), ground, and re-sieved (2 mm diameter). Afterward, iodine is extracted with 2 N sodium hydroxide and arsenious acid is added before submission for automated analysis using arsenic–cerium catalytic spectrophotometry (Risher and Keith 2009). The sample detection limit is 0.5 μg/g (Whitehead 1979). For sediment and rock samples, the sediment is dried first. Both sediment and rock samples are pulverized; afterward, the sample is mixed with vanadium pentoxide and pyro-hydrolyzed to extract iodine (Risher and Keith 2009). Later, evolved iodine is dissolved in sodium hydroxide solution and then digested with acid before submitting for arsenic–cerium catalytic spectrophotometry (Risher and Keith 2009). The sample detection limit is 0.05 μg/g (for 0.5 g sample size), with 75–90% recovery (Rae and Malik 1996).

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17.7.1.4  Vegetation/Plant The sample is prepared by microwave digestion using nitric acid/hydrogen peroxide, treated with sodium thiosulfate or ascorbic acid solution, and then subjected to ICP-MS analysis (Risher and Keith 2009). The sample detection limit is 100 pg/g, with 96–105% recovery (Kerl et al. 1996). 17.7.1.5  Iodized Salt The concentration of iodine in household salt samples can be measured using a colorimetric method by employing a WYD Iodine Checker (Risher and Keith 2009). The WYD Iodine Checker is a single-wavelength spectrophotometer that measures the iodine level (mg/kg) in salt based on the absorption of the iodine–starch blue compound at 585 nm (Risher and Keith 2009). The instrument is easy to transport and can withstand a damp and corrosive environment. It functions on 220 V AC or 9 V DC voltage, which requires six AA batteries (Risher and Keith 2009). Its range of measurement is 10–90 mg/kg with an analytical error of less than 2 mg/kg (Risher and Keith 2009).

17.8  Biological Samples 17.8.1  Thyroid Tissue Powdered or fresh tissue is digested with sulfuric acid. The sample is then converted to aluminum hexa-iodide (Al2I6) and neutron-irradiated (Risher and Keith 2009). Iodine is precipitated with palladium, and the sample is subjected to neutron activation plus Mass Spectrometry, MS (Risher and Keith 2009). The detection limit is 0.11–2.17 μg/g (range of measured values) (Boulos et al. 1973; Ballad et al. 1976; Oliver et al. 1982).

17.8.2  Urine The concentration of iodine in urine samples can be quantified in three different ways. In the first method, urinary iodine concentration is determined by quadrupole ICP-DRC-MS. Urine samples are diluted with water and chemical solutions (diluent) in the order of 1:1:8, respectively, and the diluent contains tellurium and bismuth for internal standardization. Diluted urine samples are aerosolized within the spray chamber using a nebulizer (Risher and Keith 2009). Afterward, iodine (isotope mass 127),

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tellurium (isotope mass 130), and bismuth (isotope mass 209) are measured in urine by ICP-DRC-MS using 100% argon as the Dynamic Reaction Cell (DRC) gas utilizing collisional focusing (Risher and Keith 2009). The limit of detection in urine is 1.75 μg/L, with an analytical range of 1.75–3000 μg/L (Caldwell et al. 2003, 2005). In the second method, a urine sample is purified on a Dowex 1 × 8 resin column, and the dried resin is fused with sodium hydroxide/potassium nitrate and dissolved in water (Risher and Keith 2009). A dry 0.5 mL aliquot is then placed on a polyethylene sheet, irradiated, and dissolved in water with an iodine carrier (Risher and Keith 2009). The iodine is extracted with trioctylamine/xylene, then back-extracted with 1 N ammonia, giving a silver iodide precipitate (Risher and Keith 2009). The precipitate is then subjected to INAA with gamma-ray spectrometry (Risher and Keith 2009). This method has a detection limit of 0.01 μg/L and a 94% recovery (Ohno 1971). The third method involves sample digestion in chloric acid, after which arsenious acid is added and then subjected to automated analysis by arsenic–cerium catalytic spectrophotometry (Risher and Keith 2009). The detection limit of this method is between 0.01 and 0.06 μg per sample (0.02–0.50 mL sample volume). Reported recovery is 96–97% (Benotti and Benotti 1963; Benotti et al. 1965).

17.8.3  Feces The sample is dried, pulverized, digested in a nitric acid/hydrofluoric acid, treated with sodium chloride/nitric acid, and subjected to ICP-AES analysis (Risher and Keith 2009). The sample detection limit of this method is 0.1 μg/mg, with 88–90% recovery (Que Hee and Boyle 1988). Alternatively, after the sample is dried and pulverized, it can also be digested in chloric acid and arsenious acid is then added (Risher and Keith 2009), after which the sample is subjected to automated analysis using arsenic–cerium catalytic spectrophotometry (Risher and Keith 2009). The sample detection limit is between 0.01 and 0.06 μg per sample (20–30 mg sample size), with 77–101% recovery (Benotti and Benotti 1963; Benotti et al. 1965).

17.8.4  Breast Milk The sample is mixed with acetonitrile and centrifuged, and the supernatant is dried before dissolving in acetonitrile/water and 1  mL aliquot derivatized with 2-­iodosobenzoate in phosphate buffer containing 2,6-dimethylphenol (Risher and Keith 2009). The analysis is done by HPLC with ultraviolet detection (Risher and Keith 2009). The sample detection limit is 0.5 μg/L, with a 97.6–102.4% recovery (Verma et al. 1992).

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17.9  M  ethod Used in Determining the Nutritional Iodine Status The following methods are used in determining the nutritional iodine status: Urinary Iodine Concentration (UIC), Thyroid size, Neonatal serum TSH, and Serum thyroglobulin. Practically, UIC is mostly employed in determining the nutritional level of iodine in a population because other methods such as the serum thyroglobulin concentration and thyroid size show iodine nutrition over a period of months or years (Douglas 2017). UIC indicates current iodine nutrition, and it is a good indicator of changes in dietary iodine intake over preceding days or weeks (Li and Eastman 2012). Approximately 90% of absorbed iodine is eventually excreted in the urine (Andersen et al. 2008). The dietary intake of iodine is determined from iodine morning urine samples, which include overnight bladder urine (ATSDR 2018). It is estimated from Eq. (17.1),

Iodine intake  UI 1.4,

(17.1)

where UI represents measured urinary iodine concentration and 1.4 is the average volume of urine excreted per day for 70 kg adult. Due to the fact that UIC is highly influenced by recent iodine intake, the WHO, UNICEF, and ICCIDD recommended that median UIC in schoolchildren should be used as the main indicator for assessing and monitoring the iodine nutritional status for populations (Andersen et  al. 2008; Li and Eastman 2012). The daily iodine intake for a population is extrapolated from UIC, using an estimate of mean 24-h urine volume with an assumption of 92% average iodine bioavailability. The formula is presented in Eq. (17.2),

Iodine intake  UI  0.0235  BW,

(17.2)

where UIC is in μg/L and BW is body weight in kg; median urinary iodine of 100 μg/L corresponds roughly to an average daily intake of 150 μg (Eastman and Zimmermann 2017). WHO recommended that UIC should be used to define iodine deficiency in populations using the criteria highlighted in Table 17.3. Since it is impractical to collect 24-h urine samples in field studies, UIC (μg/L) is usually measured in spot urine collections (Chung 2014). If a large number of samples are collected, variations in hydration among individuals and day-to-day variations in iodine intake generally balance each other, so that the median UIC of spot urine samples correlates well with the median from 24-h samples and with the estimated UIC excretion (μg/day) from creatinine corrected UIC (Zimmermann and Andersson 2012). The creatinine adjustment involves dividing the analyte concentration (μg analyte per liter urine) by the creatinine concentration (grams creatinine per liter urine) (Allen et al. 2004). This is because humans, especially adults, excrete creatinine at a relatively constant daily rate (mg/kg body mass) that is a function of age, gender, and body surface (Allen et al. 2004).

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Table 17.3  Criteria used in defining iodine status in the population group (WHO 2014) Criteria and population group Iodine nutrition/intake/IDD status Median UIC in children aged ≥6 years and adults (μg/L) 200 MPa) causing a profound physical or chemical change. Montmorillonite  Montmorillonite is very soft minerals that form when they precipitate from water solution as microscopic crystals, known as clay. Multinodular goiter  Multinodular goiter is a goiter in which the enlarged thyroid gland has several bumps or nodules.

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Muscovite  Muscovite a silver-gray form of minerals occurring in rocks. Nodular goiter Nodular goiter is a goiter with nodules or lumps or abnormal growths within the thyroid gland, which can be caused by benign cysts, benign tumors, or, less commonly, cancers of the thyroid. Parent material  Parent material is the underlying geological material in which soil horizons form. Quartz  Quartz is the most abundant minerals in rocks, which consist of one part silicon and two parts oxygen. Reclamation Akagare disease  Reclamation Akagare disease is the situation where naturally occurring stable iodine is released from the soil to the extent that it is chemically toxic to rice plants. Sedimentary rocks Sedimentary rocks are rocks that have formed through the deposition and solidification of sediment, especially sediment transported by water (rivers, lakes, and oceans), ice (glaciers), and wind. These rocks are often deposited in layers and frequently contain fossils. Thyrotoxicosis  Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause, which induces hyperthyroidism. Toxic goiter  Toxic goiter is a goiter that is associated with hyperthyroidism.

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Chapter 18

Naturally Occurring Arsenic and Boron in Geothermal Systems and Their Health Effects: A Case Study from Turkey Alper Baba, Yasar Kemal Recepoglu, and Hamidreza Yazdani

Abstract  Human beings have benefited from geothermal energy for different uses since the dawn of civilization in many parts of the world. However, the highest concentrations of naturally occurring aqueous arsenic (As) and boron (B) are found in certain types of geothermal fluids, generally those related to faults and volcanic activity which have caused wide-ranging alteration from argillic type to silica type. The argillic alteration zones are typically enriched in sulfur in volcanic rocks. Also, epithermal systems, which have a high concentration of As in the form of realgar and orpiment along the fracture zones of metamorphic and carbonate aquifers. On the other hand, B can easily rise to the surface by hydrothermal activity or concentrate in residual magma fluids or coexisting liquid and gas phases depending on the geology. The concentration of As and B in geothermal fluids changes in each geothermal field because of the geological properties of the region. For example, the concentration of As in geothermal fluids ranges from 10 μg/L to 50 mg/L in different parts of world whereas the concentration of B ranges from 0.04 to 119 mg/L. This chapter describes the sources and behavior of As and its relationship to elements such as B and chlorine (Cl−) using data from the samples taken from boiling and warm hot springs and geothermal wells in different geothermal fields in Turkey to evaluate their environmental impacts. Keywords  Arsenic · Altered zone · Boron · Medical geology · Human health

18.1  Introduction Geothermal fluids have recently attracted great interest as an alternative water and energy resource (Köseoğlu et al. 2011). Between the years 1995 and 2015, the trend of using geothermal fluid for various applications such as pool heating, agricultural A. Baba (*) · Y. K. Recepoglu · H. Yazdani İzmir Institute of Technology, İzmir, Turkey e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_18

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drying, greenhouse heat, area heating and cooling, snow melting, swimming pool heating, and culture aquaculture has dramatically increased (Gude 2016). Geothermal energy is extensively used for numerous applications such as power generation, district heating, chemical production, snow melting, fish production, greenhouse application, food drying, industry, and thermal tourism in many countries (Figs. 18.1 and 18.2) (Altman 2000; Baba 2015). Apart from these purposes, geothermal fluids are frequently used in heat pumps. However, geothermal brine can be extremely difficult to handle. Geothermal fluid contains high concentrations of trace elements and gases. Therefore, they can severely affect air, soil, and water resources (Fig.  18.3). With its high dissolved constituents and thermal content,

Fig. 18.1  Application of geothermal fluid for thermal tourism and fish production: (a) picture from thermal treatment in Sarayköy (Denizli), (b) picture from Blue Lagoon (Iceland), (c and d) Güroymak geothermal field (Bitlis), (e) Billoris geothermal field (Siirt), and (f) picture from fish production from geothermal field (Iceland)

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Fig. 18.2  Application of geothermal fluid for power plants and greenhouses: (a) Tuzla geothermal power plant (Çanakkale), (b) Greenhouse in Dikili geothermal field (İzmir)

Fig. 18.3  Effect of geothermal fluids on the environment: Steam and gases from Seferihisar geothermal field (İzmir), (b) recharge of geothermal fluid on soil in Tuzla geothermal field (Çanakkale), (c) Scaling in Gediz geothermal field (Simav), (d) Blowout well in Alaşehir geothermal field (Manisa)

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geothermal fluid is known to have significant impacts on the environment when disposed in an uncontrolled manner. In parallel to developing geothermal energy applications worldwide, many sites are now experiencing impacts associated not only with gases but also surface and groundwater contamination (Doğan et al. 2005; Baba 2015; Marmara et al. 2019). The chemical content of geothermal fluid can be characterized by its constituents: • • • •

Cations: Ca2+, Mg2+, Mn2+, Fe2+, Na+, K+, Rb+, Cs+ Anions: SO42−, Cl−, F−, Br−, I−, HCO3− Neutral compounds: SiO2 Dissolved gases: noble gases, NH3, CO2, H2S, N2, H2, CH4

Geothermal fluids may contain many potentially harmful trace elements such as boron (B) and arsenic (As) due to leaching of the elements by the hot waters during contact with reservoir rocks. The concentrations depend on the age of the hydrothermal system, rock type and mineralogy, gas content, heat source, temperature, permeability, liquid source, or mixing conditions (Köseoğlu et  al. 2011; Park et  al. 2012). Those potentially hazardous constituents usually exceed the maximum allowable limits recommended by the water authorities. Therefore, it is not appropriate to release geothermal fluids directly to the environment, even if it is a natural source of water. For example, when geothermal fluids with high B concentrations interact with irrigation water in agricultural areas, the B components accumulate in the soil and cause a change in the soil properties resulting in reduced plant growth, accelerated decay, and ultimately plant death (Recepoğlu et al. 2017a, b). However, B is a vital micronutrient for growing vegetables and fruits, it requires special attention because its deficiency and oversupply are detrimental for many plants, and the range between both these levels is very narrow (Güler et  al. 2011; Wolska and Bryjak 2013). For plants, B is responsible for cell wall formation and lignification which plays an important role in the structural stability. It also affects pollen germination, enzyme reactions, phenol and carbohydrate mechanisms, nucleic acid synthesis, and membrane transport. If B deficiency occurs during the growth of the plant, thickening of leaves, excessive branching, and inefficient germination are observed (Wang et al. 2014). For humans and animals, B impacts the immune system and affects hormone action and bone metabolism. Boron deficiency worsens embryo development in vertebrate animals and disrupts the absorption of elements such as magnesium, calcium, and phosphorus. Even though B is beneficial to the functioning of many organs, long-term consumption of food and water containing high B concentration results in series of problems with cardiovascular, nervous, reproductive, and coronary systems (Wolska and Bryjak 2013; Wang et al. 2014). Geothermal fluids can also contain extremely high As that can become a discharge problem. Because of the presence of As in geothermal systems, principally in geothermal deep well and/or geothermal surface manifestations, such as fumaroles, hot springs, and solfataras, the water may have serious environmental consequences. The rising geothermal fluids may contaminate groundwater aquifers, vadose zone, surface waters, and other surface environments which are crucial mediators for

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transport of As to human body via ingestion, inhalation, and skin absorption. The effects of As with a variety of complications on body organ systems (i.e., cardiovascular, endocrine, hematopoietic, hepatic, immune, integumentary, nervous, renal, reproductive system and development, and respiratory) have been stated clearly in the literature. Thus, in geothermal power generation plants, reinjection of geothermal fluids to wells is recommended after use (Bundschuh et al. 2013; Bundschuh and Maity 2015). The aim of this chapter is to give information about As and B in geothermal fluids and its effects on the environment.

18.2  Arsenic and Boron in Geothermal Fluids Before water isotopic data were available, geothermal fluids had been considered as water coming from magmatic origin. However, isotopic analyses over the last five decades have shown that they are most commonly derived from meteoric waters. The chemical composition of these fluids, which effectively forms the geothermal reservoir, has a close correlation between fluid temperature and host rock composition. The presence of As in geothermal fluids has been reported since the mid-­ nineteenth century (Webster and Nordstrom 2003). The studies showed the potential sources and levels of As in geothermal resources, especially regarding the sedimentological and tectonic properties of the region which may consist of different types of rocks, including the aquifers of the geothermal systems. For example, the circulating geothermal fluids in some thermal springs are closely related to the major faults and fracture zones. Also, in Turkey, Mesozoic carbonates are another reservoir rock of the geothermal system. Impermeable Neogene terrestrial sediments, which are composed mainly of clayey conglomerates and sands, exist in various facies and overly and constrain geothermal systems (Baba and Sözbilir 2012). Therefore, As concentrations in the geothermal fluids are extremely variable based on the hydrodynamic pattern, the geological and tectonic setting, and the thermodynamic conditions, particularly temperature and pressure. The release of As to geothermal fluids additionally depends on the availability of As in the source rocks and minerals (both primary and secondary), microbial activity, and geochemical conditions (predominantly redox state and pH) (Bundschuh et al. 2013). For these reasons, As concentrations in natural surface drainage frequently exceed current maximum allowable limits for drinking water which is 10  μg/L (WHO 1993) in terrestrial geothermal systems that have been identified in many areas of the world, including Chile, China, Greece, Italy, Japan, Mexico, New Zealand, Russia, and the USA as summarized in Fig. 18.4. Boron is also a characteristic element of late stages of magmatic activities and is considered a volatile component in magma; therefore, most existing silica and mixed silica-carbonate sinter and modern geothermal water are quite rich in B. Boron can easily be concentrated in a residual magma fluid or coexisting gas and liquid phases and brought to the surface by hydrothermal activity (Wu et al. 1984). However, experimental work on water-rock interactions has revealed that B is

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Fig. 18.4  Worldwide As content of various geothermal fields (Aloupi et  al. 2009; Birkle and Merkel 2000; Celico et  al. 1992; Ellis and Mahon 1977; Guo et  al. 2008; Karpov and Naboko 1990; Katsoyiannis et al. 2007; Kouras et al. 2007; Langner et al. 2001; Mroczek 2005; Planer-­ Friedrich et  al. 2007; Yoshizuka and Nishihama 2016; Yoshizuka et  al. 2010; Webster and Nordstrom 2003; Wilkie and Hering 1998; Zhang et al. 2008)

readily dissolved from most rocks before appreciable hydrothermal alteration occurs and that even up to 50% of the B in magmatites can be extracted by low temperature water (T = 20–22 °C) (Sauerer et al. 1990). Nonetheless, there were some difficulties when the interpretations were based only on the results of leaching experiments aimed at tracing the source of B in hot water in several geothermal areas (Lü et al. 2014). To overcome such difficulties, considerable improvement of B-isotope analytical techniques was developed where B has been found to be soluble and to have isotopic characteristics (δ11B values) that show large natural variations (−70‰ to 75‰). Due to these characteristics, B becomes ideal for determining specific sources and geochemical processes. In geothermal systems, B is derived from rock-water interactions. Like Sr isotopes, the B isotopic compositions of geothermal fluids are strongly dependent on the signatures of the source rock such as

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basalt, carbonate rocks, evaporites, and granite (Lü et al. 2014). Moreover, the B and Cl− concentrations can be used for determining the provenance of B in water resources because Cl− is accepted as a conservative ion even in geothermal environments. In thermal waters containing juvenile water, B exists at different concentrations and the ratio of B/Cl ranges from 2  ×  10−2 to 0.4 (Dotsika et  al. 2006). In general, it can be concluded that the distribution of B among hydrothermal waters is affected by the provenance, vapor pressure, temperature, and lithology of aquifers (Dotsika et al. 2011).

18.3  Arsenic in Geothermal Fluids in Turkey Turkey, one of the most seismically active regions on earth, has a high level of geothermal energy potential because of its tectonic and geological characteristics. It is located within the Mediterranean Earthquake Belt, whose complex deformation results from the continental collision between the Eurasian and African plates (Bozkurt 2001). The border of these plates constitutes seismic belts marked by young volcanic and active faults, while the faults allow circulation of water, as well as heat. The distribution of hot springs in Turkey roughly parallels the distribution of the fault systems, young volcanism, and hydrothermally altered areas (Şimşek et al. 2002; Şanlıyüksel and Baba 2011). The first geothermal research and investigations in Turkey was started by the General Directorate of Mineral Research and Exploration (MTA) in the 1960s. One hundred-eighty-five geothermal sites have been discovered since 1980 by the MTA. There are a total of about 1500 thermal and mineral water spring groups in the country as shown in Fig. 18.5 (MTA 1980; Şimşek et al. 2002; Şimşek 2009). Most of these geothermal fluids originated from the Menderes Metamorphic Massif which discharges from the rims of east–west-­ trending faults that form the Büyük Menderes (BMG), Küçük Menderes (KMG), Gediz (GG), and Simav Grabens (SG) in the Western part of Turkey. Bottom hole temperatures of wells are as high as 287 °C in Alaşehir in the Gediz Graben (GG) and 242 °C in the Denizli-Kızıldere site of the Büyük Menderes Graben (BMG). In addition, there are several hot springs aligned along E to W direction of the Küçük Menderes Graben (KMG), GG, and BMG with discharge temperatures between 25 and 100 °C (Karakuş and Şimşek 2012). As popularity of geothermal energy consumption increases in Turkey, the environmental impact of geothermal energy becomes an important key. Contamination of surface and subsurface waters with toxic heavy metalloids is the most severe environmental impact of geothermal energy. These contamination problems are mainly attributed to flawed well construction, faulty reinjection applications, and uncontrolled discharge of waste geothermal fluids to surface waters (Aksoy et al. 2009). Consequently, surface and groundwater resources become chemically and thermally polluted. As and B occur in regions of high alteration which include silica type to argillic type to prophylitic type mineral assemblages at depth (Fig. 18.6). The advanced argillic alteration zones are enriched in sulfur in volcanic rocks and

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Fig. 18.5  Tectonic map of the eastern Mediterranean region showing structures developed during the Miocene to Holocene time and distribution of geothermal areas around Turkey (compiled from: Şimşek et  al. 2002 and Yiğitbaş et  al. 2004). (SBT Southern Black Sea Thrust, NAFZ North Anatolian Fault Zone, NEAFZ Northeast Anatolian Fault Zone, EAFZ Eastern Anatolian Fault Zone, WAGS Western Anatolian Graben System, DSF Dead Sea Fault Zone, BZS Bitlis-Zagros Suture) (Baba and Ármannsson 2006)

secondary epithermal gypsum, which is associated with As in the form of realgar and orpiment occurring along the fracture zones of metamorphic and carbonate aquifers. B is unevenly distributed among various rock types in geothermal fluids in Turkey, and especially enriched in decreasing order: tourmaline gneiss, quartz vein, illite-chlorite-feldspar zone, and quartz-chlorite schist zone (Vengosh et al. 2002). The concentration of As in geothermal fluids is different in each geothermal field because of the different geological properties of the region. The concentration of As in Turkish geothermal waters ranges from 10 to 6936 μg/L. The highest As concentration was found in the Hamamboğazı (Uşak) geothermal spring with a value of 6936  μg/L.  The concentration of As in Turkish geothermal fluids is shown in Fig. 18.7. In addition, B concentration is also quite high in the geothermal systems of Turkey (Fig. 18.8). The concentration of B is as high as 70 mg/L in some geothermal fields such as those in the Aydın, Manisa, and Düzce Regions. Boron is derived from volcanic and sedimentary rocks, but may also be controlled by degassing of magma intrusive (Baba and Ármannsson 2006; Baba 2018). Figure 18.9 illustrates the dominant hydrochemical features of geothermal fluids in Turkey. Each geothermal fluid has a different composition. Generally, most of the geothermal fluids which have a deep circulation are Na-HCO3− type, whereas shallow fluids are mostly of the Ca-HCO3 type. Along the coastal region such as western Turkey, hot spring exhibited a Na-Cl type with high concentrations of Na+ and Cl−.

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Fig. 18.6  Alteration zones around geothermal fields: (a and b) Tuzla geothermal field (Çanakkale), (c–e) Alaşehir geothermal field (Manisa), (f) Kestanbol geothermal field (Çanakkale)

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Fig. 18.7  Distribution of arsenic in geothermal fields in Turkey. (Some data taken from MTA 2005)

Fig. 18.8  Distribution of boron in geothermal fields in Turkey. (Some data taken from MTA 2005)

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Fig. 18.9  Chemical properties of geothermal fluids in Turkey: (a) Piper diagram, (b) Schoeller diagram (Baba 2018)

18.4  R  elation of Arsenic and Other Compounds in Geothermal Fluids As, B, and Cl− are major components in geothermal fluids. The principal sources of As, B, and Cl− in the fluids of the high-temperature geothermal systems include precipitation, infiltration of seawater into the bedrock, the host rocks of the fluids,

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and magma volatiles. Figures 18.10 and 18.11 show the As-Cl and As-B relationships in groundwater samples collected from different locations in Turkey. Boron and Cl− are highly mobile in geothermal systems and provide remarkable information on the source fluids of the geothermal systems and various processes occurring within the systems including boiling and mixing. Chloride is generally taken to be conservative, i.e. once in solution, it stays there. Boron may also be conservative, depending on the type of minerals that form from solution and take up B. Due to its correlation with Cl− and As in geothermal systems has also been taken to be 100000 10000

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conservative although closer examination shows that it is not. Arsenic can be removed from solution by its uptake into iron hydroxides and sulfide minerals. In common types of volcanic rocks, all these elements are present to some extent in easily soluble compounds. Thus, hydrothermal experiments have demonstrated that these elements are largely transferred into solution without appreciable alteration of the rock-forming minerals (Giroud 2008). The behavior of As in groundwater is closely connected with that of sulphur. Metal sulfides are often rich in As and, hence, their oxidation can be a source of dissolved As (Ravenscroft et al. 2009). The relation of sulfate and As in the geothermal fluids of Turkey is presented in Fig. 18.12. Generally, there does not appear to be a good correlation between As and sulfate in Turkish geothermal waters. Lithium is also one of the important elements in geothermal fluids. However, while there is no good correlation between Li and As, there is better correlation between Li and B in Turkish geothermal fluids (Figs. 18.13 and 18.14).

18.5  H  ealth Benefits of Geothermal Fluids and Their Health Risks Due to Arsenic Toxicity Balneology is the practice of using geothermal fluid for the treatment and cure of illnesses. Geothermal fluids have been used for bathing and health in different civilizations such as Chinese, Japanese, Ottomans, and Romans for centuries. In addition, bathing in geothermal fluids and using the muds are thought to give certain health benefits to the user (Lund 2010).

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The geothermal fluid at Xiaotangshan Sanitarium, northwest of Beijing, China, has been used for medical purposes for over 500 years (Ibrahimova 2006). Currently, the 50 °C fluid is used to treat high blood pressure, rheumatism, skin disease, diseases of the nervous system, ulcers, and generally for recovery after surgery. In Rotorua, New Zealand, at the center of the Taupo Volcanic Zone of North Island, the Queen Elizabeth Hospital was built during World War II for U.S. servicemen and later became the national hospital for the treatment of rheumatic disease with

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geothermal fluids (Lund 2010). In Beppu on the southern island of Kyushu, Japan, the geothermal fluids meet many needs: heating, bathing, cooking, industrial operations, agricultural research, physical therapy, recreational swimming, and even a small zoo. The fluids are promoted for digestive system troubles, nervous troubles, and skin troubles. Many sick and crippled people come to Beppu for rehabilitation and physical therapy. There are also eight Jigokus (burning hells) in town showing various geothermal phenomena that are used as tourist attractions (Taguchi et al. 1996). In the former Czechoslovakia, the use of geothermal fluids dates back before the occupation of the Romans and has had a recorded use of almost 1000 years. Depending on the chemical composition of the geothermal fluids, availability of peat and sulfurous mud, and climatic conditions, each sanatorium is designated for the treatment of specific diseases. The therapeutic successes of these spas are based on centuries of healing tradition (balneology), systematically supplemented by the latest discoveries of modern medical science (Lund 1990). Bathing and therapeutic sites in the U.S. have included: Saratoga Springs, New  York; Warm Springs, Georgia; Hot Springs, Virginia; White Sulfur Springs, West Virginia; Hot Spring, Arkansas; Thermopolis, Wyoming; and Calistoga, California (Lund 2000). The original use of these sites was by Indians where they bathed and recuperated from battle. There are over 115 major geothermal spas in the U.S. with an annual energy use of 1500 TJ (Lund 1996; Ibrahimova 2006). Also, in Turkey, geothermal fluid has been used for the health issue in different regions such as Balçova (İzmir), Afyonkarahisar, and Şanlıurfa. Although geothermal fluids offer many health benefits to humans as explained above, intake of these fluids directly to the human body may cause some severe damage due to the inclusion of some toxic elements such as As and B. The occurrence of As in groundwater and its effects on millions of individuals throughout the world (Baba et al. 2012; Chakrabati et al. 2018) is a major health and environmental concern because As is one of the well-known toxins and is generally found in water as oxyacids in two main forms, arsenite [As(III)] and arsenate [As(V)]. Arsenite is known to be more toxic and soluble than arsenate. Because As(III) can easily bind with specific proteins and be transported into the cells. On the other hand, As(V) cannot enter cells to be reduced to the +3 state. Also, As(III) can bind with -SH group present in many proteins and enzymes thus inhibiting their activity. Most forms of organo-arsenicals such as arsenobetaine are metabolized by our body and eliminated via urine. Further, inorganic forms of As are better absorbed by the body than organic As. Though, it is believed, in general, that organic As is non-toxic, recent research has shown that some organic As compounds show similar toxicity as that of inorganic As (Spehar et al. 1980). These factors contribute toward the different toxicity of As(III) and As(V) (Baba and Sözbilir 2012; Kobya et al. 2015; Molin et al. 2015; Siddiqui and Chaudhry 2017). For that reason, arsenate has a greater tendency than arsenite for removal from the solution by the addition of metal cations. The metal-arsenate complex usually precipitates in the form of Mn(AsO4)mH2O. The stability of the precipitation depends on the conditions such as the cation used to form the precipitate, temperature, pH, and redox potential (Yang et  al. 2013). Arsenate is the main species in surface water at pH  5–12, whereas

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arsenite is usually found under reductive conditions and is therefore the dominant species in groundwater at pH 2–9 (Smedley 2003). Exposure to As at a much higher concentration of 10 μg/L, which is the guideline for drinking water recommended by the WHO in 1993, leads to serious health problems (WHO 1993; Long et al. 2012; Huling et al. 2017). Arsenic in drinking water has been classified as a ‘Group 1 carcinogen’, causing bladder, lung, and skin cancer in humans, and other symptoms of chronic As poisoning such as skin lesions and high As concentrations in hair and nails. Circulatory disorders and diabetes caused by As have also been mentioned in the literature (Şık et  al. 2015, 2017; Almberg et al. 2017; Nidheesh and Singh Anantha 2017). In the report of Layton et  al. (1981) for the Health and Environmental Risk Analysis Program, they claimed that the ingestion of surface water or groundwater contaminated with As derived from geothermal fluids could cause skin cancer. To find of the possibility of skin cancer risk by the potential impacts of directly releasing waste geothermal fluids to surface waters was assessed. The chosen case for analysis was the operation of the Wairakei geothermal power plant in New Zealand, which discharges all of its waste geothermal fluids to a local river. The released wastewater caused an approximately 39 μg/L increase in the As concentration in the river. According to risk calculation, the resulting lifetime risk of ingesting that contaminated water was surprisingly as high as 1.6 × 10−2, which depends on a lifetime probability of cancer equal to 4 × 10−4 L/μg, derived from epidemiological studies of Taiwanese exposed to elevated levels of As in drinking water from wells. However, the risk estimate was probably incorrect because at low concentrations it might kill parasites or cure certain diseases that make the differences in toxicology and benefits are rather hard to distinguish (Mayer et  al. 1993) and therefore the linear, no-threshold dose-response model was inapplicable. In addition, mammals have a detoxification mechanism of methylation; and As concentrations in drinking water of up to 100 μg/L do not appear to result in excessive body burdens (Layton et al. 1981). Bundschuh et al. (2013) measured concentrations of As, As(III), and As(V) in geothermal fluids in western Turkey. According to this study, there was also an unknown As species calculated as the difference between total As concentrations and sum of reported inorganic As species. Overall, the data showed As(III) as the dominant species in most of the samples. The reported unknown As species possibly are thioarsenates. During the past few years, environmental effects of geothermal energy production have become a key topic to be researched in Turkey due to the contamination of surface waters and groundwaters with hydrothermally derived As as the most serious consequence of geothermal energy production. Irrigation and drinking water resources, such as groundwater and surface waters close to geothermal fields, have become polluted with tremendous levels of As and other toxic elements such as B by the wastewater derived from geothermal plants (Bundschuh et al. 2013). As documented in previous studies, skin lesions in the inhabitants of the Emet District of Kütahya Province, Turkey, was observed due to high As exposure through dermal contact (Doğan et al. 2005). Furthermore, near to this region, the Simav District of Kütahya Province, which is situated in an area of active tectonism,

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with the presence of alteration zones and geothermal resources, the maximum As levels is as high as 561 μg/L in groundwater resources (Gündüz et al. 2015). In this region, 221 cases of death between 1998 and 2005 were investigated, and cardiovascular diseases (45.2%) were estimated to be the major cause of death, followed by respiratory system illnesses (5.7%) and cancers (15.8%). Among all neoplasms, lung cancers were the most predominant (34.1%) cancer type, which was followed by stomach (20%), colon and prostate (20%), and liver (17.1%) cancers (Gündüz et al. 2015).

18.6  Results and Conclusions Geothermal fluid can basically be utilized for either the immediate use of district heating or power generation. Besides those purposes, geothermal fluid found use in geothermal heat pumps where condensed water is separated from steam and re-­ injected into the wells or directly discharged to the environment. Although utilization of geothermal fluid can be an alternative solution to the water scarcity problem, it may contain potentially toxic elements including B and As. High concentrations of As and B have been observed in geothermal fluids in Turkey. These elements can have a direct impact on human health through mixing with surface and groundwater resources used for drinking and irrigation. Based on in vitro, animal, and human experiments, WHO revised the upper limit of B concentration in drinking water as 2.4 mg/L in 2011 since B is a bioactive element in nutritional amounts that beneficially affects bone growth and central nervous system function, alleviates arthritic symptoms, facilitates hormone action, and is associated with a reduced risk for some types of cancer (WHO 2011; Nielsen 2014). Although there are no findings about relatively high B intakes by drinking water in various places in the world that cause adverse health effects and there is a wide window (10–20-folds) between B intakes with possible adverse effects based on the previous study, the suggested beneficial consumption of B is 1.0 mg/day. For example, in Turkey, a population exposed to drinking water containing up to 29 mg B/L in a B mining and production site, no adverse effects on health and fertility were observed over three generations. However, high As concentrations has carcinogenic effects on human health and potentially accumulate in agricultural products. Additionally, high B concentrations can have a detrimental effect on crops based on their sensitivity (Bundschuh et al. 2013; Nielsen 2014). Baba (2010) and Gündüz et  al. (2017) previously reported human health effects associated with the use of As-contaminated local freshwater resources for drinking and irrigation. These water sources are affected by As-rich geothermal fluid. They also reported carcinogenic effects on people living in this region. Therefore, alternative drinking water sources need to be implemented in the study area to avoid further human health effects from drinking of As-contaminated water. In addition, proper management strategies should be adopted in order to avoid cross contamination of fresh groundwater resources. Furthermore, it is

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essential to note that geothermal wells should be planned carefully and its environmental risk should be mitigated properly for future generation water demand. Acknowledgements  The authors would like to thank Dr. Robert B.  Finkelman (University of Texas at Dallas) for his valued comments and support.

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Chapter 19

A Review on the Occurrence of Some Potentially Harmful Elements in the Natural Environment and Their Health Implications: Examples of Fluoride, Iron and Salinity in the South-Eastern Kenya Region Patrick Kirita Gevera, Mark Cave, Kim Dowling, Peter Gikuma-Njuru, and Hassina Mouri

Abstract  Makueni, Machakos and Kitui Counties, located in the Arid and Semi-­ Arid land (ASAL) region of south-eastern Kenya, receive low and unreliable rainfall which necessitates a high dependence on groundwater for potable, domestic and agricultural purposes. The geology of the region is dominated by metamorphic rocks of the Precambrian Mozambique Mobile Belt and Tertiary-Pleistocene volcanic rocks both of which are known to have highly variable concentrations of diverse naturally occurring potentially harmful elements. The geochemical composition of local soils and groundwater reflect the chemistry of the parent geological material and this constrains the type and concentrations of elements and nutrients in drinking water and locally produced food. This review reports the occurrence of some commonly reported potentially harmful elements, fluoride (F−), iron (Fe) and salinity, in groundwater, farm soil and commonly consumed food crops in parts of south-­ central Kenya and considers their potential health implications. P. K. Gevera (*) · H. Mouri Department of Geology, University of Johannesburg, Johannesburg, South Africa M. Cave British Geological Survey, Nottingham, UK e-mail: [email protected] K. Dowling Department of Geology, University of Johannesburg, Johannesburg, South Africa Federation University, Ballarat, VIC, Australia e-mail: [email protected] P. Gikuma-Njuru Department of Environmental Science and Land Resources Management, South Eastern Kenya University, Kitui, Kenya e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_19

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Drinking water issues are documented. The presence high F− in drinking water is associated with dental fluorosis in Machakos and Makueni Counties. Iron in Makueni and Kitui Counties is associated with an undesirable brown colour and taste in drinking water. Salty water is a common drinking water problem in most parts of Kitui and Makueni Counties that has led to the abandonment of shallow wells. Groundwater and spring water analysis show elevated F− (max. 9.30 mg/l), Fe (max. 7.60  mg/l) and salinity (max. hardness, chloride (Cl−) and magnesium (Mg) of 950 mg/l, 260 mg/l and 122.40 mg/l, respectively). In soils, elevated F− levels were reported in Kitui County while acidity and salinity in soil were reported throughout the region. The effects of high F− soils are not reported, but acidic and saline soils were found to be unproductive for maize and green grams farming. Chemical and nutritional analyses of food crops grown in the area are essential to determine overall health implications on the local population. Detailed soil and groundwater geochemical databases are required in the region in order to assess the potential health implications of the natural environment on the local population. Keywords  Potentially harmful elements · Groundwater · Soil · Food-crops · Fluoride · Iron · Salinity

19.1  Introduction Natural resources such as water, soil and vegetation, including crops, are essential to sustain human life and support local communities. Reliable clean water is a fundamental need of any population and groundwater resources provide major sources of domestic and agricultural water supply in many parts of the world (Adimalla and Li 2018). Eighty percent of Kenya is classified as water-scarce, with limited surface water in most arid and semi-arid regions, and consequently, groundwater is relied upon for domestic and agricultural needs (JICA 2004; Attibu 2014). Groundwater chemistry is primarily influenced by lithology, stratigraphy and the structure of the geological formations through which the water flows (Ng’ang’a et al. 2017). Elements that are released into groundwater are leached from minerals present in aquifer rocks (Ng’ang’a et al. 2017) and hence understanding local geological processes in an area is essential to understanding the processes controlling groundwater quality. The local geology similarly influences the nutritional quality of food crops grown in an area. Weathering of rocks releases minerals which then become available for plant uptake (Kabata-Pendias 2001a). The type, concentration and availability of naturally occurring nutrients in soil are derivatives of the contributing geological formations, and their availability is controlled by various weathering and mobilization processes (Kabata-Pendias 2001a). To investigate the nutritional quality of food crops grown in an area, it is necessary to understand the physico-chemical properties of the local rock-soil interface and the chemical uptake processes in plants and crops.

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The occurrence of potentially harmful elements at concentrations that can result in or can potentially cause adverse biological effects to resident communities may be viewed as a pollutant (Chapman 2007). Human activities including urbanization, industrialization and rapid population growth have introduced different potentially harmful elements into groundwater systems and soil leading to their degradation. Natural processes such as volcanic/hydrothermal activities, dust storms and erosion have also led to the introduction of elevated levels of these elements in groundwater and soils. These processes have rendered water sources unsafe for human consumption and soils unsuitable for agriculture in different parts of the world (Yadav et al. 2018). It is important to note that concentration is the key factor as elements that are essential to life at low doses may be toxic at high doses irrespective of the source or vector of the pollutant. Additionally, the duration of exposure to elevated concentrations of essential elements can also influence the level of toxicity. Long-term exposure to slightly elevated concentrations of elements can have similar detriments to short-term exposure to higher elevations. Due to the direct interaction between Kenya’s rural population and the natural environment, exposure to potentially harmful elements through pathways such as drinking water, food consumption, air or particulate exposure is noted and may pose health hazards (JICA 2004). In Kenya, studies pertaining to natural contaminants and their health implications focus on groundwater where high F− content is the most reported, particularly in the Rift Valley region (Gevera and Mouri 2018). However, due to the complex geology across Kenya, other regions might have similarly high concentrations of potentially harmful elements that are available to humans through various pathways and may present a significant health risk. Such areas include the south-eastern part of the country covering Makueni, Kitui and Machakos Counties (Mwamati et al. 2017; Ng’ang’a et al. 2018). This region is of interest because it contains both volcanic rocks related to the formation of the Rift Valley and metamorphic rocks of the Mozambique Mobile belt (Ng’ang’a et al. 2015; Mwamati et al. 2017). These geological provinces host high concentrations of potentially harmful elements such as F−, Fe, As and salts (dominated by sodium (Na), chloride (Cl−), magnesium (Mg), sulphate (SO42−) and nitrate (NO3−)) which are reported to be mobilized into groundwater (Smedley et  al. 2002; Gevera and Mouri 2018) and some can potentially be taken up by food crops (Rahman and Hasegawa 2011; Dagnaw et al. 2017). Human populations living in these geological zones have reported health implications of some of these elements (Smedley et al. 2002; Dagnaw et al. 2017; Gevera and Mouri 2018). The chemical composition of irrigation water and farm soils highly influences the type and quantity of elements/nutrients available for plant uptake (Kabata-­ Pendias 2001a). Therefore, it is important to properly investigate groundwater quality, soils and food in south-eastern Kenya with respect to concentration and distribution of naturally occurring potentially harmful elements that can affect human health. This review aims to summarize current research on three specific naturally occurring potential harmful elements/parameters (F−, Fe and salinity) in water, soil and food crops and address their health implications in the study region, and highlight areas for further work.

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19.2  Study Area 19.2.1  Location, Climate and Economic Activities Three counties in the south of Kenya: Makueni, Machakos and Kitui are considered (Fig. 19.1). The counties, which initially formed part of the Eastern Province, fall under the Arid and Semi-Arid Land (ASAL) regions of Kenya, which receive low rainfall resulting in seasonal and unreliable surface water sources for agricultural, pastoral and domestic use (Mailu 1994; Ng’ang’a et  al. 2017). Limited surface water sources are one of the biggest challenges faced by the local county governments (Mailu 1994; Ng’ang’a et al. 2017). To address water shortages, the counties, with the help of the national government, have drilled boreholes as well as constructing sand and earth dams to improve the reliability of domestic and agricultural water supply (TANATHI Water Services Board 2018). This solution has had intended and unintended consequences. However, although groundwater availability improves the surety of water and food supply, it may also bring negative health effects in case of the presence of natural contaminants.

Fig. 19.1  The location of Kitui, Makueni, and Machakos Counties in Kenya. (Modified from Muthami (2011) ArcGIS shapefile)

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The three counties have a rural setting where most of the population practice small-scale farming. The region has a bimodal rainfall pattern where the long rains, with a heavier downpour, are between March and May while the short rains are between October and December (Mailu 1994; Mbithi 2017; Mwamati et al. 2017). The regional annual rainfall ranges from 250 to 1050 mm while temperatures range from 14 to 35 °C (Mbithi 2017; Mugo et al. 2016; Mwamati et al. 2017). The main surface water sources include Athi River, which passes through all the three counties, and Tiva River in Kitui County (Mwamati et al. 2017). The high reliance on small-scale farming in the region means that most of the population consume locally produced food crops. Therefore, the geochemistry of the local soils and groundwater significantly impacts the nutritional and health outcomes for the local population.

19.2.2  Geology and Hydrogeology 19.2.2.1  Geology The geology of the region is predominantly composed of Precambrian metamorphic rocks of the Mozambique Mobile Belt (MMB) (Dodson 1953; Saggerson 1963; Mailu 1994; Ng’ang’a et  al. 2015). These rocks are overlain, in some areas, by younger Tertiary-Pleistocene volcanics (Dodson 1953; Saggerson 1963). Granitoid gneisses and quartzites, with high resistance to weathering, form distinctive outcrops such as the Mbui-Nzau hills in central Makueni and Kilala hills in Machakos, respectively (Dodson 1953; Saggerson 1963). The low-lying flat lands are covered by the less-resistant biotite gneisses and schists in most parts of the region except in western Kitui, where the Yatta phonolites form the Kapiti plain which traverses in a north–south direction (Dodson 1953; Mailu 1994; Mwamati et al. 2017). The metamorphic rocks in the area are dominantly microcline-rich biotite gneisses and muscovite schists which are often associated with pyrite-rich muscovite quartzite, marble, banded gneisses, granitoid gneisses, granites and pegmatites (Dodson 1953; Saggerson 1963). These metamorphic rocks are rich in biotite, muscovite and accessory minerals such as diopside, hornblende, garnets, magnetite and ilmenite, which can host considerable concentrations of potentially harmful elements such as F−, Fe and As (Dodson 1953). Most metamorphic rock areas are covered by sandy and loamy soils which are acidic and reddish to grey in colour due to the presence of iron oxide minerals (Dodson 1953). The volcanic rocks in the area are mainly composed of the Tertiary phonolites in western Kitui and Pleistocene porphyritic olivine basalts found in central and southern Makueni (Dodson 1953). These rocks form hilly basalt cones and flows prominently in the Chyulu ranges south of Makueni as well as phonolite plateau in western Kitui (Saggerson 1963; Mwamati et al. 2017; Mailu 1994; Ng’ang’a et al. 2015). Basalts and phonolites are known to influence groundwater F− levels in the area (Mailu 1994; Mwamati et al. 2017). These volcanic rocks are mostly covered by fine-grained, clay-rich back cotton soils (Dodson 1953).

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19.2.2.2  Hydrogeology Aquifers in the region are located in rock pore spaces, joints or contact zones between rock types in both metamorphic and volcanic rocks, with the latter reported to contain higher yield aquifers (Mailu 1994; Ng’ang’a et al. 2015, 2017). The most studied volcanic aquifers in the region are those from the Makueni County. Aquifers in these volcanic rocks are found in joints or contact zones and may discharge as springs when contacts between volcanic rocks and underlying metamorphic rocks are exposed (Mailu 1994; Ng’ang’a et al. 2015). Contact zone exposures in the area have given rise to springs such as Makindu, Kiboko, Mzima and Umami, some of which are piped and provide water for the residents of local towns in the Makueni County (Mailu 1994). Basalts make very productive aquifers due to their highly porous contact zones (Mailu 1994; Ng’ang’a et al. 2015). Although the aquifers in the volcanic rocks in the region are highly productive, the water quality in these rock types is usually poor due to a high F− content associated with the volcanic rocks (Mailu 1994; Ng’ang’a et al. 2018). In metamorphic rocks, groundwater is found in secondary porosity developed by weathering processes or at contact zones (Ng’ang’a et al. 2018). Generally, these rocks have low porosity due to their tightly packed crystalline structure resulting in low-yield aquifers (Mailu 1994; Ng’ang’a et al. 2018). Low yield and unproductive boreholes have been reported in some parts of Machakos (Nyamai et al. 2003) and Makueni (Mailu 1994; Ng’ang’a et  al. 2018) Counties covered by metamorphic rocks. However, due to the vast extent of metamorphic rocks in the region, the total volume of water extracted from them exceeds that from volcanic rocks (Ng’ang’a et al. 2018). The main water quality problems reported in the basement aquifers is high salinity and F− content (Ng’ang’a et al. 2018). There are also several productive shallow and unconfined sand and alluvium layers that are tapped by hand-­ pumped wells in the region (Ng’ang’a et al. 2018), but the water quality from most of these shallow aquifers has not been studied.

19.3  Potentially Harmful F−, Fe and Salinity in Groundwater 19.3.1  Introduction Groundwater quality is affected by high levels of physical, chemical (inorganic or organic), bacteriological or radioactive agents. Chemical agents may be introduced into groundwater through anthropogenic and natural processes. Natural chemical agents of groundwater are often overlooked in most drinking water quality studies due to the slow manifestation of human health-related issues (Talukder et al. 2016). Health implications of these elements are usually observed long after exposure commenced (Talukder et al. 2016). Recent studies have highlighted the significance of chemical contaminants in drinking water, especially groundwater sources, with some agents such as F− and As receiving detailed scrutiny in regions of India, Bangladesh, Taiwan and the USA (Shankar et al. 2014; Rasool et al. 2018). Studies

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have also demonstrated the health effects of other natural contaminants such as salinity and Fe (Delange 1994; Talukder et al. 2016). Groundwater geochemistry is influenced by both geogenic and anthropogenic factors (Edmunds and Smedley 2013; Ng’ang’a et al. 2017). However, this review will only focus on geogenic factors in the three counties in southern Kenya. The region is dominantly rural with limited industrial or large-scale commercial agricultural activities, so anthropogenic factors are seen as minimal contributors (Mwamati et al. 2017). Geogenic sources of potentially harmful elements are mainly controlled by the local lithological and geochemical processes (Ng’ang’a et al. 2017). Some of these processes include rock type, mineral composition, weathering processes, mineral precipitation, pH changes, sorption/desorption and oxidation/reduction (Finkelman et al. 2018). Minerals present in rocks and soil dissolve in groundwater as it moves through rock pore spaces and fractures. For drinking water to be considered safe for human consumption, concentrations of chemical components and physical parameters should be within the standards set by governing authorities such as the World Health Organization (WHO) and the Kenya Bureau of Standards (KEBS). In the three counties, high concentration of elements including F− and Fe, as well as physical parameters including salinity, total hardness, electrical conductivity (EC) and Total Dissolved Solids (TDS) have been reported in higher concentrations than the recommended limits by the WHO (Krhoda 1989; Mailu 1994; Ng’ang’a et al. 2017).

19.3.2  F  luoride, Fe and Salinity in Groundwater in Makueni, Machakos and Kitui Counties The MMB is a metamorphic province running through the eastern to southern Africa cutting through Ethiopia, Kenya, Tanzania and Malawi. In Kenya, Makueni, Machakos and Kitui Counties are mostly covered by these rock types most of which are associated with several potentially harmful elements including F−, Fe and salinity (Malago et al. 2017). The volcanic rocks of the East African Rift Valley, similar to those in the study region, have also been associated with F−, salinity and As in groundwater in Ethiopia, Kenya, Tanzania and Uganda (Rango et al. 2013; Malago et al. 2017; Gevera and Mouri 2018). In the three counties, potentially harmful elements such as F−, Fe and salts are reported (Mbithi 2017; Mwamati et  al. 2017; Ng’ang’a et al. 2018). A compilation of major elements and physical parameters reported in surface and groundwater in the three counties is presented in Table 19.1.

19.3.3  Fluoride Fluoride (F−) is an ion of the element fluorine (F), which is the most electronegative and the 15th most abundant element on the Earth’s crust (Ozsvath 2009; Fordyce 2011). It is a lithophile element that concentrates in late-crystalizing rocks, and

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average concentrations range from as low as 100  mg/kg in ultramafic rocks to 2000 mg/kg in alkaline igneous rocks (Gizaw 1996; Ozsvath 2009; Edmunds and Smedley 2013). Due to F− capability to react with most elements, it is present in a wide range of compounds (Martínez-Mier 2012). Fluoride is often enriched in late-­ crystallizing minerals such as fluorite (CaF2), fluorapatite (Ca10(PO4)6F2), villiaumite (NaF), hornblende ((Ca,Na)2–3(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2), biotite (K2(Mg,Fe)4(Fe,Al)2[Si6Al2O20](OH)2(F,Cl)2), topaz (Al2SiO4(F,OH)2) and apatite (Ca5[PO4]3(Cl,F,OH)) (Smedley et al. 2002; Edmunds and Smedley 2013; Gevera and Mouri 2018; Yadav et al. 2018). These minerals are common in granites, phonolites and tuffs formed from highly evolved magmas as well as metamorphic rocks such as biotite gneisses, schists and granitoid gneisses (Edmunds and Smedley 2013; Yadav et al. 2018). Sedimentary rocks such as marine shales or those with igneous protoliths may also show high F− concentrations (Ozsvath 2009). Fluoride can form part of the main mineral component such as in fluorite, biotite and hornblende or occur as a trace component such as in apatite (Fordyce 2011; Edmunds and Smedley 2013).

19.3.4  Treatment and Prevention Several studies have highlighted different treatment or prevention methods for dental fluorosis. Prevention is preferable; however, prescription of vitamins C and D3, and Ca slows but does not reverse the process of dental fluorosis (Chen et al. 1997; Rango et al. 2012; Mehta and Shah 2013). Prevention of uptake requires analysis of source waters and intervention as needed. Fluoride can be reduced in drinking water through different defluoridation techniques such as adsorption, precipitation and membrane separation technologies (Schoeman 2012; Jamode et al. 2013). Some of the commonly used defluoridation methods in Africa include bone char, granulated bone media, activated alumina and Nalgonda method (Kloos and Haimanot 1999; CDN 2009; Gómez-Hortigüela et  al. 2013). Defluoridation programs have been effective in parts of South Africa (Schoeman 2012), Tanzania and Kenya (Dahi 2016), and less effective in some parts of Tanzania and Ethiopia (Dahi 2016). Factors contributing to success include the method of defluoridation, ease and cost of operation and maintenance of the equipment, effectiveness in F− level reduction and how the method affects the general water quality (Dahi 2016). For example, the bone char method has been used in Tanzania, Ethiopia and Kenya with success attributed to the use of readily available material (bones), ease of operation and lack of unwanted by-products in the filtered water, while the Nalgonda technique was unsuccessful in Tanzania due to the presence of sludge in the filtered water as a by-­ product of alum and lime used in the technique (Dahi 2016).

19  A Review on the Occurrence of Some Potentially Harmful Elements in the Natural… 645 Table 19.1  Major chemical and physical parameters in ground and surface water of Makueni, Machakos and Kitui Counties in southern Kenya Water source Concentration Area (locality) Fluoride (mg/l) Borehole 6.50–8.20 Makueni (Wote and Makindu) Borehole 3.0 mg/l cause a bitter taste in drinking water (WHO 2003a; Raju 2006). Divalent Fe2+ is usually soluble and mostly occurs in anaerobic conditions, such as in deep groundwater systems, and only precipitates into the insoluble Fe3+ with an increase in dissolved oxygen (Gad et al. 2016; WHO 2017). The insoluble Fe3+ usually settles out as brown (rusty) silt and is often seen in water pipes when Fe concentrations exceed 0.3  mg/l (WHO 2017). The dissolution and precipitation of these two Fe species are redox controlled and not only can it affect the organoleptic properties of water but can also release contaminants adsorbed onto Fe-rich minerals into groundwater (Borch et al. 2009).

19.3.13  I ron in Groundwater in Makueni, Machakos and Kitui Counties In the Kitui County, Fe values ranging from 0.01 to 1.63  mg/l were reported in boreholes from volcanic aquifers (Mwamati et al. 2017). In the Makueni County, Fe concentrations ranging from 1200 mg/l) (National Health and Medical Research Council et al. 2011). Poor water quality caused by high salinity is a significant groundwater contamination issue, having implications for human health as well as livestock and agriculture (Kumar et al. 2009). In Kenya, high salinity is reported in the Rift Valley lakes (Jirsa et al. 2013). Lake Magadi, for example, located in the southern end of the Rift Valley has deposits of trona (Na2CO3·NaHCO3·2H2O); a non-marine evaporate mineral that is mined for NaCO3 (McNulty 2017). High salinity in groundwater in Kenya has been reported in several areas including the Mombasa island aquifers due to ocean-water intrusion, granitic aquifer in the Mumias area of western Kenya and in the Lotikipi aquifer in northern Kenya (Barasa et  al. 2018). In the arid eastern region of Kenya, which includes Makueni, Machakos and Kitui Counties, Krhoda (1989) characterized groundwater as high in Cl, Na, HCO3 ions and TDS.

19.3.16  Health Effects of Salinity in Drinking Water The World Health Organization (WHO) proposes sodium levels of 200 mg/l and chloride of 5  mg/l for desirable drinking water taste (WHO 2003b). Food is the main source of dietary Na but drinking water may contribute to up to 44% of intake in some communities (Talukder et al. 2016). The daily recommended consumption level of Na is 2 g; however, in areas with high saline waters, this value has been reported to be as high as 25 g, such as in the coastal regions of Bangladesh (Khan et al. 2011; Vineis et al. 2011; Talukder et al. 2016). High salinity in drinking water has been associated with several health complications such as skin diseases, respiratory infections, diarrhoea, high blood pressure, miscarriage and eclampsia in pregnant women (Khan et al. 2011; Vineis et al. 2011; Talukder et al. 2016; Nahian et al. 2018). However, the strong link to high blood pressure as shown by several epidemiological studies is of concern (Morimoto et al. 1997; Pomeranz et al. 2002; Khan et al. 2011; Talukder et al. 2016). In addition to these health effects, high saline water is unpalatable for drinking which presents a

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significant issue in terms of meeting the drinking water demand. Saline water provides a favourable environment for malaria and cholera vectors and therefore can indirectly contribute to an increase in these diseases (Talukder et al. 2016). Since the main chemical component of highly saline water is NaCl, most studies discuss the health implications of this salt. The physiological function of Na in the body is to maintain the cellular fluid volume, and concentration in the cell plasma affects the cell water content (Farquhar et al. 2015; Talukder et al. 2016). The normal blood Na content ranges from 135 to 145 mmol/l and an increase in this amount, usually associated with high salt intake, will lead to an increase in intravascular fluid volume leading to higher blood pressure (Talukder et al. 2016). High blood pressure can cause several conditions including cardiovascular complications, stroke, renal failure, kidney stones, osteoporosis and thickening of blood vessels (Farquhar et al. 2015; Talukder et al. 2016). The prevalence of hypertension in Kenya, which is currently at 6–50%, dependent on region, has increased over the past 20 years and is higher in population living in urban areas compared to rural areas (Mathenge et  al. 2010; Ahmed 2012; Hendriks et al. 2012; Oti et al. 2013; Muchira et al. 2015; KNBS 2015). However, this rise was attributed to the adaptation of a sedentary lifestyle and an increase in the consumption of processed food (Ahmed 2012; KNBS 2015).

19.3.17  G  roundwater Salinity in Makueni, Machakos and Kitui Counties Several recent studies within the three counties have identified areas with high salinity. In the Yatta Plateau, western part of Kitui County, groundwater was reported to have electrical conductivity range of 184–2270  μs/cm and TDS range of 114–1407  mg/l, which were slightly below the WHO-recommended values of 2500 μs/cm and 1500 mg/l, respectively (Mwamati et al. 2017). Despite these values being below WHO limits, about 80% of the local population interviewed in the study reported salty water as the main drinking water issue in the area (Mwamati et al. 2017). In the Makueni County, groundwater in the Makindu area was reported to have average Cl− values of 260 mg/l, hardness values of 700 mg/l, alkalinity values of 851  mg/l and Mg values of 122.4  mg/l which were higher than the WHO-­ recommended values of 250 mg/l, 500 mg/l, 500 mg/l and 100 mg/l, respectively (Mbithi 2017). Springs in Makueni were, however, classified as fresh with TDS values less than 1000 mg/l (Mailu 1994). Generally, boreholes and shallow wells in the basement aquifers within the Makueni and Kitui Counties are saline and the high salinity has led to the abandonment of boreholes and wells in some areas such as in eastern Makueni (Ng’ang’a et  al. 2018). There are no reported studies on groundwater salinity in the Machakos County.

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19.3.18  H  ealth Effects of High Salinity in Drinking Water in Makueni, Machakos and Kitui Counties In a study to determine the variation of blood pressure and pulse rate in rural populations of different ethnicities in Kenya, Christensen et al. (2016) studied members of the Kamba community from the Kitui County aged between 17 and 68 years. The study reported a low prevalence (8.5%) of high blood pressure and noted that adult males formed the dominant group with higher blood pressure. The low prevalence of hypertension can be attributed to a non-sedentary lifestyle in the rural setting of the region; however, correlation to genetic factors and high salinity water consumption are yet to be investigated. Overall, limited research addresses the prevalence of hypertension in the study region. The Kenya National Bureau of Statistics (KNBS 2015) report on non-­ communicable diseases risk factors shows that about 61% of Kenyans living in rural areas have never been screened for hypertension. This highlights the limited knowledge of the disease prevalence in rural settings such as the study region. Although the prevalence of hypertension in Kenya, including the study region, is mostly associated with a sedentary lifestyle, there is a need to determine whether high salinity in water can contribute to hypertension and other related diseases, besides the effect on water taste.

19.3.19  Redox Conditions Reduction-oxidation (redox) processes in water affect the release, concentration, mobilization, persistence, bioavailability as well as degradation of many organic and inorganic constituents (Borch et al. 2009; Jurgens et al. 2009). In aquifers, these processes control the solubility of elements from the aquifer rocks and sediments and govern the extent of their mobility and fate in groundwater (Naudet et al. 2004; Jurgens et  al. 2009). Determination of redox conditions in water is important because these reactions can result in the introduction of contaminants such as As, Fe, Mn and gasses such as methane (CH4) and hydrogen sulphide (H2S) which can affect water quality (Jurgens et al. 2009; Jacks 2017). The redox state of groundwater in an area can be characterized as either oxic, suboxic, mixed or anoxic based on the concentrations of specific parameters including dissolved O2, Fe, Mn, NO3−, SO42−, sulphides (S2−) and carbon dioxide (CO22−) (Jurgens et  al. 2009). Respiration of microbial organisms is usually the driving mechanism behind redox reactions, as they transfer electrons between donor and acceptor elements or compounds while gaining energy in the process (Borch et al. 2009; Jurgens et al. 2009). Oxic conditions are usually present in O2-rich waters such as recently infiltrated groundwater and shallow aquifers, while anoxic conditions are common in O2-­ deprived old groundwater in deep aquifers (Borch et al. 2009; Jacks 2017). Oxic

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groundwater is usually associated with concentrations of contaminants such as Fe3+, Se and NO3− at levels higher than recommended for drinking water, while anoxic groundwaters are usually associated with parameters such as Fe2+, As, Mn and CH4 (Borch et al. 2009; Jacks 2017). For example, the dissolution of As-rich Fe3+ oxides in shallow aquifers has been associated with the mobilization of geogenic As in Bangladesh (Borch et al. 2009). It is therefore important to understand the predominant redox conditions in groundwater in an area in order to determine and predict their effects on water quality.

19.3.20  Redox Conditions in Groundwater in the Study Region Groundwater quality studies in the region have incomplete data with regards to redox conditions. There are no published studies reporting the concentration of dissolved O2 in groundwater, while other studies lack one or more of the other parameters required for redox characterization as explained by Jurgens et  al. (2009). However, the principles of redox reactions can be used to explain the occurrence of potentially harmful elements such as Fe in groundwater in the area. Oxidizing conditions in groundwater are known to convert soluble Fe2+ to insoluble Fe3+ which results in brown staining in water systems and clothes (Kabata-Pendias 2001; Raju 2006; Borch et  al. 2009). The unpleasant brown colour and staining of clothes reported in Kitui and northern Makueni (Mwamati et al. 2017; Ng’ang’a et al. 2017, 2018) indicates the presence of Fe3+ in the water. Fe-rich minerals are known to be associated with adsorbed As which can be mobilized in groundwater by a change in redox conditions (Borch et al. 2009). Groundwater is critical to human health and prosperity in this region and groundwater extraction may influence redox and in turn dissolution of elements. Therefore, it is essential that a detailed groundwater quality characterization is completed in order to determine the redox conditions governing groundwater quality.

19.4  Potentially Harmful F− and pH in Soil 19.4.1  Introduction Soil is essential to life because it acts as the source of nutrients for plants and ultimately humans. It also provides a habitat for organisms, a filtration system for water and a reservoir for key breakdown products from rocks. Soil degradation is usually reported in industrial, commercial, agricultural and urban settlement areas where anthropogenic activities release high concentrations of contaminants into soil. The natural release of different elements and compounds into soil happens through a slow weathering process. The accumulation of elements in soil is

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governed by their speciation and the soil physico-chemical properties (KabataPendias 2001a). Once accumulated in soils, elements can be depleted through several processes such as leaching, erosion, volatilization and plant uptake (Chang and Page 2000; Kabata-Pendias 2001a). Understanding the dynamics and characteristics of soil chemical composition in an area is important because elements, especially potentially harmful ones, can be directly ingested from soil and can accumulate in plants which may then be unsafe for human and stock consumption.

19.4.2  F  luoride and pH in Soil in Makueni, Machakos and Kitui and Counties Due to the high dependence on small-scale agriculture for food provision in the three counties (Mugo et al. 2016), it is important to understand the impact of soil quality on the production of food. Small-scale farming has been practised in the region from the early 1930s and it is one of the main economic activities of the region (Achieng and Muchena 1979; Kasperson et al. 1995; Mugo et al. 2016). The presence of high concentrations of potentially harmful elements in groundwater in the region increases the need to understand the soil geochemistry so that their possible availability for plant uptake and water dissolution can be understood. Examples of potentially harmful physico-chemical parameters in soil reported in the study region include fluoride, high acidity and salinity (Ellenkamp 2004; Ochieng 2007; Adama 2014; Mugo et al. 2016). Table 19.3 provides a summary of reported fluoride and pH levels in soil in the region.

19.4.3  Fluoride Fluoride is released from rocks into soil and is subsequently adsorbed onto mineral surfaces and dissolved in soil solution (Cronin et al. 2000; Yadav et al. 2018). The average concentration of F− in soils ranges from 20 to 500 mg/kg but soils derived from F−-rich rocks or in hydrothermal mineralization areas can have F− values of up to 1000 mg/kg (Kabata-Pendias 2001; Edmunds and Smedley 2013; Bhattacharya and Samal 2018; Yadav et al. 2018). Soil properties such as pH, salinity, exchangeable Na percentage and surface area of the particles affect F− mobility (Ozsvath 2009; Yadav et al. 2018). Slightly acidic conditions (pH 5.0–6.5) favour high F− retention onto soil (Ozsvath 2009). Therefore, at pH 5.0–6.5, F− solubility is at the lowest and sorption at the highest, while at pH values less than 5.0 and higher than 6.5, its solubility and desorption increases.

19  A Review on the Occurrence of Some Potentially Harmful Elements in the Natural… 659 Table 19.3  Concentrations of fluoride and pH in soils of Makueni, Machakos and Kitui Counties in southern Kenya Concentration/level Fluoride (mg/kg) 390–469 pH 2.6–8.0 5.7–8.3 5.0–7.8 4.6–4.9 3.8–7.2

Area (locality)

n

Reference

Kitui (Mwingi)

18

Ochieng (2007)

Kitui Kitui Machakos Machakos Makueni

– 90 240 144 150

Mugo et al. (2016) Adama (2014) Adama (2014) Ellenkamp (2004) Adama (2014)

The surface area of soil particles can also determine the sorption capacity of the soil (Ozsvath 2009). Fine-grained soils with clay minerals or high organic content have high surface area for mineral sorption and thus can retain high F− content, while coarse-grained soils such as sands have smaller surface area and therefore can retain low F− content (Ozsvath 2009). Fluoride in soils presents a pathway to humans through weathering and aqueous leaching into groundwater or its accumulation in food crops (Bhattacharya and Samal 2018; Yadav et al. 2018).

19.4.4  F  luoride in Soils in Makueni, Machakos and Kitui Counties F− content in rocks described in Sect. 19.2.2.1 of this work is high and hence there is a potential for high F content in soil that requires investigation. Ochieng (2007) reported F− values ranging from 390 to 469 mg/kg in soils from Mwingi area in the northern part of Kitui. Most of the soil samples analysed had F− levels in the upper limit of the global F− range of 20–500 mg/l in soils (Ochieng 2007). Saline soils had relatively higher F− values compared to acidic soils (Ochieng 2007). The study also reported a positive correlation between elevated F− levels in soils and groundwater in the area. This positive correlation was also reported in soils and groundwater of the Kenyan Rift Valley (Kahama et al. 1997). Although only one study (Ochieng 2007) reported high F− concentration in soils in the study region, there is a high probability of its occurrence in other parts of the region due to several compounding factors. The presence of high F− in groundwater in the area indicates a likelihood of high concentration in rocks and soil, as reported in the Kitui County and the Kenyan Rift Valley (Kahama et al. 1997; Ochieng 2007). Soils in the region have clay content ranging from 17 to 53% and pH range of 6.8–7.7 (Ochieng 2007; Mora-Vallejo et  al. 2008), indicating their suitability for high F− retention. Clay soils in F− rich areas have been shown to have elevated fluoride concentrations (Ozsvath 2009). Ando soils derived from volcanic ash in the Rift Valley region of Kenya were reported to have high F− adsorption capacity due to

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their high Al, clay and organic content (Zevenbergen et al. 1996). This indicates that soils in south-central Kenya region with similar properties can retain high F− content in farms using irrigation water with high F− concentrations. More studies are required. Due to the lack of F− studies in soil in the area, there is no ability to determine the link between its concentration in soil to that in drinking water, food crops and ultimately the health effects. Similarly, there are limited studies reporting F− concentrations in soil in Kenya. Regions such as the Rift Valley are known to have high F− concentrations in groundwater. However, the data on F− in soil is required in order to establish the total F− intake from local drinking water and food in these regions. Additionally, direct ingestion of soil due to hand-to-­ mouth activities particularly in children, inhalation of dust as well as ingestion of unwashed food crops can be a significant pathway of F− into the body. These gaps create a need to determine the concentrations of F− in rocks and soils in the region. This is essential in determining whether soil, dust and food grown in the area can be a major source of fluoride, besides drinking water to the local population.

19.4.5  Soil pH Soil pH is influenced by the presence of soluble and readily dissolved inorganic salts including Na, Cl−, Ca, K, CO32−, SO42−, NO3− and HCO3− at high concentrations (Corwin and Yemoto 2017). Soil pH can affect plant growth as well as shallow groundwater quality through dissolution and precipitation of elements found in varying concentration in soils (Mugai 2004; Kumar et  al. 2009). High salinity is common in soils found in arid and semi-arid regions, such as in the study region, usually caused by elevated salt levels due to high evaporation, capillary rise and low precipitation (Mugai 2004; Haplogypsids et al. 2006; Attibu 2014). About 40% of land located in ASAL regions of Kenya has soils with high salinity (Mugai 2004; Attibu 2014). Mugai (2004) reported saline soils in eastern Kenya to be rich in Na and Cl− salts. Soil pH affects what plant species grow well in the region. A study to evaluate soil suitability for maize farming in Kenya indicated that farms in the region with soil pH lower than 5.5 and greater than 8.0 were classified as unsuitable for maize farming (Adama 2014).

19.4.6  Soil pH in Makueni, Machakos and Kitui Counties In the Kitui County, a wide range of soil pH from 2.6 to 8.34 has been reported in agricultural land (Adama 2014; Mugo et al. 2016). The soils had Cation Exchange Capacity (CEC) ranging from 0 to 51.6  mEq/100  g, with the majority of soils recorded in the top quartile of this range. In the Machakos County, soil pH ranges from 4.60 to 7.77, where red loam soils were slightly acidic and black clay soils

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were moderately alkaline (Adama 2014; Karuma et  al. 2015). The CEC values ranged from 2.5  mEq/100  g in acidic soils to 30.5  mEq/100  g in alkaline soils (Ellenkamp 2004; Karuma et  al. 2015). High CEC values, such as in the Kitui County, indicate the soils have a high potential to hold positively charged ions which includes Na, Mg, Ca and K (Mugo et al. 2016). In the Makueni County, pH ranges from 3.78 to 7.20 where soils in the central region (Makindu-Kiboko) were characterized as high in Ca, Mg and CO32− (Adama 2014; Mbithi 2017). Acidic soils (pH 200 >200

Calcic

>150

Magnesiac Fluorurate

>50 >1

Ferrous Sodium-rich

>1 >200

Low-sodium

10 μm) are generally restricted to the upper airways, including the nose, mouth, and upper respiratory tract, and thus can be associated with bronchial respiratory disorders such as asthma, tracheitis, pneumonia, allergic rhinitis, and silicosis. These particles can also damage external organs—mostly causing skin and eye irritations, conjunctivitis, and enhanced susceptibility to ocular infection. Inhalable particles, those smaller than 10 μm, often get trapped in the nasal cavity or the trachea. However, finer particles may penetrate the lower respiratory tract and enter the bloodstream, where they can affect all internal organs and be responsible for cardiovascular disorders. A global model assessment in 2014 estimated that exposure to dust particles caused about 400,000 premature deaths by cardiopulmonary disease in the over 30-years population (https://public.wmo.int/ en/our-mandate/focus-areas/environment/sand-and-dust-storm. Accessed 15 Mar 2019). Morman and Plumlee (2014) report that ailments associated with airborne dust include asthma, meningitis, and pneumoconiosis. They quote studies that found

724 Fig. 22.1  Urban dust storms. (a) London, England. March 31, 2014. (b) Beijing, P.R. China. March 29, 2015. (c) Sydney, Australia. Sept. 23, 2009. (d) Phoenix, AZ, USA. August 2, 2018

G. Filippelli and R. B. Finkelman

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mineral dust events were associated with increased risk of hospitalization for pediatric asthma. It is not only the minerals that contribute to health problems. Lyles et al. (2008) found that dust and sand storms are a persistent problem delivering significant amounts of particulates via inhalation into the mouth, nasal pharynx, and lungs. The health risks of this dust inhalation are not well studied nor effectively characterized. Experiments were designed to study the chemical composition, mineral species, and characterization of biologic flora, including bacteria, fungi, and viruses. They found a significant biodiversity of bacteria of which ~25% are known pathogens with some showing significant antibiotic resistance. Viral analysis indicated high level of virions with RNA viruses representing a large percent. They concluded that the dust with its microbial and metal content constitutes a significant health risk.

22.2.2  Pressure-Treated Wood Pressure-treated wood is made chemically to withstand the elements and ward off termites, microorganisms, and fungal decay. A commonly used chemical had been chromated copper arsenate, though currently the most common chemicals used are alkaline copper quaternary, copper azole, and micronized copper azole. Pressure-­ treated wood has been widely used in the building industry in homes, offices, and in playground construction. On December 31, 2003, the US wood treatment industry stopped treating residential lumber with arsenic and chromium (chromated copper arsenate: CCA). This was a voluntary agreement with the United States Environmental Protection Agency. However, chromated copper arsenate may still be used for outdoor products and nonresidential construction like piers, docks, and agricultural buildings. Moreover, many of the decks and playground constructions treated with chromated copper arsenate are still in use. In some situations, previous poor practices in industry have left legacies of contaminated ground and water around wood treatment sites. Treated wood may present certain hazards in some circumstances, such as during combustion or where loose wood dust particles or other fine toxic residues are generated or where treated wood comes into direct contact with food and agriculture, or where children may be exposed to the chemicals leached from pressure-treated wood used in urban playgrounds and decks (Ottesen et al. 2011). Stillwell and Gorny (1997) state that due to the massive amounts of CCA-treated wood sold each year, the extent of dispersal of these additives from the wood could have a considerable environmental impact. The potential toxicity of copper (Cu), chromium (Cr), and arsenic (As) to humans, animals, and plants is well documented. In analyzing the soil beneath decks, made of pressure-treated wood, they found that at each site, the average Cu, Cr, and As content in the soil samples, taken beneath the deck, was elevated with respect to the average in the control soil. In all cases, except for the Cr content of one deck, this elevation was statistically significant.

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They conclude that the results demonstrate that significant amounts of Cu, Cr, and As leach from the wood and manifest itself in the soil. In a similar study Townsend et al. (2013) found the arithmetic mean concentrations of arsenic, chromium, and copper in 65 surface soil samples, collected from below CCA-treated structures, were 28.5, 31.1, and 37.2 mg/kg, respectively, whereas the mean concentrations of arsenic, chromium, and copper in the control samples were 1.34, 8.62, and 6.05 ­mg/ kg, respectively. Arsenic concentrations exceeded Florida’s risk-based soil cleanup target level for residential settings in all 65 surface soil samples. Decker et al. (2002) raised the issue of occupational exposure to these potentially toxic elements in pressure-treated wood. They found that at the indoor sanding operations wood dust concentrations were significantly greater than those measured outdoor. Personal impactor sampling demonstrated that the mean total airborne concentration of arsenic was consistently above recommended occupational exposure levels at the indoor work site, and occasionally at the outdoor work sites. Although we found no reports of health issues caused by the metals released from the pressure-treated wood, it should be kept in mind that the residence time of these metals in soil is measured in hundreds of years (Kabata-Pendias 1995).

22.2.3  Natural Disasters Natural disasters such as earthquakes, volcanic eruptions, floods, landslides, tsunamis, etc., are all too common phenomena that impact the lives and livelihoods of millions of people each year. Their occurrences are commonly reported on the front pages of newspapers, headline stories on TV news, and displayed prominently on the Internet. The greater the disaster, the greater is the coverage. But soon the rescue workers have done all they can and pack up their gear leaving the impacted area. At about the same time the reporters move on to the next major story leaving the local people to clean up the debris and to try to put their lives back together. However, an aspect of these natural disasters that receives little attention is the long-term health consequences. These natural disasters cause considerable disruption to the environment, both to the built environment and to the natural environment resulting in human exposure to dust, minerals, trace elements, and radioactivity that may cause long-term health impacts. The impacts to urban areas can be particularly severe. Ash and gases from volcanic eruptions know no boundaries; they blanket urban as well as rural areas exposing residents to a range of potentially harmful emissions (Fig. 22.2a–c). Here we are not talking about the ultimate health impacts of volcanic eruptions as seen in the mummified remains in Pompeii and Herculean. We are concerned more with the long-term health consequences of exposure to volcanic gases and dust. Exposure to the volcanic dust and gases can cause and have caused widespread and serious health problems. Weinstein et al. (2005) provide a comprehensive list of toxic compounds of volcanic origin. They include various sulfur compounds, hydrogen sulfide, fluoride

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Fig. 22.2  Urban volcanic ash deposits. (a) Chile. (b) Japan. (c) Indonesia

compounds, chlorine compounds, carbon dioxide and carbon monoxide, crystalline silica, and mercury vapor. The health issues include trauma, skin burns and lacerations, smoke inhalation, asphyxiation, asthma, silicosis, toxic element exposure, suppression of the immune system, abrasion of nose, throat, etc., nonspecific

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pneumoconiosis and chronic obstructive pulmonary disease in populations from prolonged exposure to ash (Horwell and Baxter 2006). Earthquakes can have equally devastating effects (Fig.  22.3) in urban settings causing substantial disruption of the infrastructure. Collapse of building will generate enormous amounts of dust (Fig. 22.4) exposing residents to quartz, asbestos, and possibly lead and radioactive materials. Landslides (Fig.  22.5), tornadoes, and floods caused by tsunamis, hurricanes, or just heavy rains will disrupt the environment and expose residents to foreign materials, including human pathogens, which may impact their health (Fig. 22.6). Urban centers are particularly vulnerable to natural disasters. The heavy concentration of people, the reliance on transportation systems, damage to infrastructure such as hospitals, and water and sewerage systems can leave many urban residents vulnerable to exposure to harmful natural materials resulting in acute or chronic medical geology health problems. Geoscientists can still play an important role in human-made disasters. For example, they can use their tools and expertise to characterize the dust generated by the destruction of buildings, thus providing the medical community the information it needs to assess the potential health problems.

Fig. 22.3  Urban earthquake in China exposing residents to quartz, asbestos, and possibly lead and radioactive materials

Fig. 22.4  Manhattan on September 11, 2001

Fig. 22.5  Landslide exposing residents to quartz, asbestos, and possibly lead and radioactive materials

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Fig. 22.6  Flooding in Houston, TX

22.2.4  Occupational Health Issues Inhalation of airborne minerals including clays has impacted the heath of millions. Morman and Plumlee (2014) describe common chronic diseases associated with or exacerbated by exposure to airborne dust, generally rich in clays. These include silicosis, pneumoconiosis, asthma, and meningitis. Silicosis, also known as Potter’s rot, can be caused by inhalation of clays, has the distinction of being the most widespread occupational lung disease. It affects people the world over but is more prevalent among workers in developing countries. This is particularly true in P. R. China where, in 2013, pneumoconiosis accounted for nearly 88% of all reported occupational diseases in China, of which about 35% were confirmed to be silicosis (Tse et al. 2015). The occurrence of silicosis in China resulted from prolonged exposure to high levels of clay containing dust from a variety of industrial activities involving mining, rock drilling, and construction activities. Despite adoption of dust control measures (e.g., increasing ventilation, wet processes, and the use of protective masks), these clay-related health problems are still on the increase. There is no known cure for silicosis; treatments instead focus on symptom relief and reducing exposure to any lung irritants. Ross et al. (1993) provide a comprehensive review of health issues associated with inhalation of mineral dusts. They specify a number of occupational pneumoconiosis experienced by workers exposed to clay dust including talc pneumoconiosis and kaolinosis. Factory workers and anyone working in foundries, metal working facilities, smelters, coal-burning power plants, construction, sand blasting, stone cutting and

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polishing, etc., may be exposed to a range of potentially hazardous elements and minerals. Even people who use firing ranges for their training or recreation have shown extremely elevated amount of lead in their bloodstream, which have caused numerous incidents of depression, anxiety, and aggression (Laidlaw et al. 2017b). The International Labor Organization (ILO 2010) list of occupational diseases contains more than 20 elements, mineral dust including silica, asbestos, and erionite as possible occupational disease-causing agents. It is clear that urban dwellers can be just as susceptible to medical geology problems from exposure to natural materials such as minerals and trace elements as are rural residents.

22.2.5  Urban Gardens and Use of Fertilizers In 2015 it was estimated that urban gardens supply 20% of the world’s food supply (https://www.greenbiz.com/article/urban-farms-now-produce-15-worlds-food) and this trend is growing (Fig. 22.7). It is especially important in areas of cities that are not adequately served by vendors of fresh fruits and vegetables. However, there are some risks in growing crops in urban soil (Brown and Jameton 2000). Residues from leaded gasoline use, potentially harmful trace elements from long-gone factories, power plants, and other industrial activities may linger in the soil for thousands to tens of thousands of years. Many fertilizers, used to enhance plant growth, contain high levels of trace elements, and pressure-treated wood, used for garden

Fig. 22.7  An urban garden

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borders and formally used in urban playgrounds, contain high levels of arsenic, copper, and chromium (see above discussion on pressure-treated wood). The elements are generally present in low concentrations, but they may be substantially concentrated by some of the plants growing in the soil. Inexpensive chemical analysis of the soil and crops can determine if there are any potential concerns from the soil and crops.

22.2.6  Lead in Paint, Gasoline, Soil, and Water Supplies The element lead has been used by humans for thousands of years. Even though its negative health effects have been known for centuries, lead has been widely used in paint, gasoline, batteries, and pipes since the Industrial Age. The addition of lead in paint enhanced durability and flexibility, and many lead-based paints contained up to 15% lead by mass. A typical older city in the USA might have well over 50% of its structures originally painted with lead-based paint. This paint might be on indoor walls and exteriors, but even brick and stucco structures often have window sashes, doorways, and sills painted with lead-based paint. Degradation of this paint (Fig. 22.8), and inadvertent consumption by infants and toddlers, resulted in children being admitted to hospital with severe lead poisoning—this issue was exacerbated for children with low nutritional status and lower income (higher rental property percentages with related lower maintenance standards). The link between lead poisoning and paint was obvious, and in the later 1940s a combination of consumer group and health professionals helped push legislation to remove lead from the paint production. Similar pushes to remove lead from gasoline have occurred internationally, although these have varying levels of success. The removal of lead from paint production was an extremely positive development, but it did little to deal with the simple fact that many older cities have Fig. 22.8 Peeling lead-based paint showing characteristic “alligator texture.” (photo by Gabriel Filippelli)

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substantial proportions of housing stock covered with lead-based paint, in various stages of disrepair and degradation. Additionally, these older homes frequently had either lead water service lines or used lead solder to seal galvanized iron or copper connections on water lines. The use of lead in water systems followed a similar trajectory as lead-based paint, and has a similar legacy—many older structures pose drinking water hazards with respect to lead. These hazards have been exemplified by high profile water quality crises such as have occurred in Washington, DC in 2002 and Flint, MI in 2014 (Roy and Edwards 2018). In both cases, the decades of protective “plaque” that formed inside of water delivery systems and, thus, protected the delivered water from interacting with the lead-rich pipes or solder, were stripped out because of chemical changes to the source water, resulting effectively of flushing captured lead from the inside of the pipes to the insides of children and adults. Both events were handled terribly from a public health perspective—namely, it took well over a year of evidence of thousands of now permanently lead-poisoned children to push the cities to even begin investigating the issue, let alone mitigating it. This delay is part of the problem—public health reporting has proven effective for infectious disease detection and intervention, but has failed in the case of the “forgotten lead” problem. Although these are but two examples, and both from the USA, the health risks posed by lead in older infrastructure are acute, and cannot be overlooked. The transportation industry is not immune to lead legacies either, of course. Lead additives for gasoline were developed as an antiknock engine formula in the 1920s, and the proliferation of motor vehicles in the middle part of the century was fueled by gasoline enriched with tetra-ethyl lead (Mielke 1994). Phased out beginning in the late 1970s, there is evidence that this regulatory step alone was responsible for the dramatic decline in US population blood-lead levels since. But as with lead in paint and in water systems, that legacy lead from gasoline emissions is still present in the environment, particularly near roadways and city centers. And for lead its immobility in the environment results in most of the accumulated deposition from airborne and paint degradation sources being hyper-accumulated in the upper inches of soil, posing a risk from inadvertent ingestion and in dust generated from that lead-rich repository. It poses a particular risk to urban gardeners and produce as well if it is not detected and remediated.

22.2.7  Effects of Lead on Humans Compared to other chemicals of environmental concern, the uptake mechanisms and toxic effects of lead are relatively well understood. The primary pathway of lead uptake in humans is via ingestion, where lead is absorbed in the intestine and incorporated in the body (Angle et  al. 2001). Human absorption potential for lead is dependent mainly on age—the proportion of ingested lead that is taken up in the body is typically less than 5% for adults whereas it is as high as 50% for children (Roberts et al. 2001). The presence of elevated blood lead in infants and children

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leads to permanent neural differentiation defects resulting in lowered intelligence quotient (IQ), learning disorders, and attention deficit hyperactivity disorder (Nevin 2000; Demetriades 2010, 2011; Nigg et al. 2008). Because of their high ingestion efficiency and the rapid neural differentiation during early brain and nervous system development, children are especially vulnerable to permanent effects of lead poisoning. A majority of blood lead becomes incorporated into bone, which itself becomes a longer-term source of lead to the biological system—bone is regenerated on timescales of months to years, continually leaking additional lead into the system (some evidence suggests that elderly suffering from osteoporosis can have elevated blood-lead levels from bone-loss related sources, decreasing cognitive function (Needleman 2004)). For this reason, children treated by medical interventions like blood chelation may continue exhibiting toxic levels of lead in their blood. Furthermore, as neither the placenta nor mammary glands are a perfect barrier to lead, pregnant and lactating mothers with elevated blood-lead levels may themselves pose a health risk to babies and fetuses. In some inner-city neighborhoods of Indianapolis, a typical older USA midwestern city, approximately 8% of youth from 1–6 years old exceed the earlier screening standard for the “safe” blood-lead level (BLL) of 10 μg/dL (Morrison et al. 2012). But with the reduction in this screening level by the U.S. Center for Disease Control and Prevention (U.S. CDC) to 5 μg/dL in May 2012 (in response to numerous studies which find significant neurologic and cognitive effects at lower BLLs; Lanphear et al. 2005; Schnaas et al. 2006; Canfield et al. 2007; Chiodo et al. 2007; Jusko et al. 2007; Miranda et al. 2007; Surkan et al. 2007; Nigg et al. 2008), this percentage of lead-affected children increases to 27% of children in these neighborhoods, and could be worse because very few children are actually lead tested in some regions (e.g., Beidinger et al. 2018). Thus, lead exposure continues to be a public health threat, largely from legacy sources of lead, the product of a century of lead use in urban areas. Additionally, most areas with elevated soil lead also include elevated levels of other metals, such as cadmium, manganese, and arsenic. Individually, each of these metals poses certain neurological and developmental risks, but collectively as metal mixtures, their toxic effects may be significantly increased, particularly in utero and in young children (Wright et al. 2006; Hu et al. 2007; Yorifuji et al. 2011). Based on previous work (Filippelli et al. 2005; Laidlaw et al. 2005, 2012, 2016; Laidlaw and Filippelli 2008), soil with elevated lead and the periodic resuspension of dust particles from this soil play a major role in lead exposure to urban children. The full range of toxic effects of lead in the human system is still not known, and deserves further study (e.g., adult health impacts on liver and heart; Obeng-Gyasi et al. 2018a, b). But the persistent presence of lead in children is a public health issue of a first order (Karr 2008), and will remain so for quite some time given extant legacy sources of lead from a host of practices, including mining. (Fig. 22.9a, b shows Kabwe abandoned mine and local lead “recyclers” collecting discarded slag for reprocessing and lead extraction.) Lead exposure is listed among the factors that contribute to the global human burden of disease (WHO 2013). Exposure to lead is related to a wide range of adverse health effects with high exposures being related to death and serious

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Fig. 22.9 (a) Broken Hill Mine facility, Kabwe, Zambia. This facility was a zinc and copper mine and processing plant, which left large waste piles of lead-enriched (up to 10% lead by weight) tailings, such as seen in the background, scattered throughout the urban area (photo by Gabriel Filippelli). (b) Backyard “Re-mining” of lead-rich tailings for melting and eventual resale, Kabwe, Zambia (photo by Gabriel Filippelli)

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conditions such as encephalopathy (Needleman 2004). However, lower, chronic levels also result in impairments of cognition, motor skills, behavior, and the immune system and there appears to be no lower threshold below which there are no adverse effects (Needleman 2004; Binns et al. 2007; Lanphear 2017). The neurobehavioral toxicity caused by lead places great economic burdens on families and societies (Gould 2009). An economic analysis conducted in the United States found the current costs of childhood lead poisoning to be US $43 billion per year. A recent cost– benefit analysis undertaken in the United States found that for every US $1 spent to reduce lead hazards, there is a benefit of US $17–220 (Mielke et al. 2006). This cost–benefit ratio is better than that for vaccines, which have long been described as the single most cost-beneficial medical or public health intervention (WHO 2010). A clear cause–effect relationship for lead has resulted in substantial and highly effective mitigation actions, although the limitations in current practices focusing on one particular source (degrading lead-based paints in older homes; Lanphear et al. 1998) have masked somewhat the widespread problem of highly elevated soil lead in urban areas (Mielke and Reagan 1998; Laidlaw and Filippelli 2008; Zahran et al. 2013; Laidlaw et al. 2016). Indeed, as paint-related sources were mostly eliminated in the US 60  years ago, and other probably more harmful sources such as leaded gasoline and lead solder in plumbing were phased out shortly after, the legacy of these sources have been imprinted into the urban fabric in the form of soil contamination. The very soil under urbanites’ feet is now a primary exposure pathway for lead, creating pockets of poor health and potentially contributing to trends in violent crime in many cities (Wright et al. 2008). Even after decades of research and action, the incidence of lead poisoning remains high in urban areas of the US, and globally. At particular risk are urban youth from low-income families and countries who inhabit the polluted inner neighborhoods of older cities without the benefits of adequate nutrition, education, and access to health care (Filippelli and Laidlaw 2010). A newer environmental health model is helping us understand this exposure, and to provide several tools to mitigate the harmful impacts of urban lead. To transition our cities into safer and more health sustainable systems, and to provide environmental justice (that is, equal access to a safe and healthy environment) for a full spectrum of urban dwellers, newer approaches are needed to assess current lead exposure mechanisms and to fully understand the health implications of chronic lead exposure—some of this has to revolve around soil geochemistry and legacies of lead-enriched urban soil. Components of such soil acted as a highly efficient trap of anthropogenic lead over about 100 years of urban development, and are now returning that lead to the next generations of people living in cities. Higher income countries have monitoring systems in place to measure pollution levels and to identify pollution sources, and are often drivers of research into the impacts of pollutants on environmental and human health and effective mitigation techniques to reduce exposures. But even these countries have structural flaws in their pollution protection systems in that monitoring does not always equate to intervention (e.g., Taylor et al. 2014). A classic example of this structural flaw is lead poisoning in children, where intervention only occurs after a child has

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presented with lead poisoning, at which point most of the neurological damage is already in place. While levels of lead in children have dropped significantly since the elimination of the use of lead additives in gasoline and its removal from other sources (paint, food, toys), some 500,000 US children still have an elevated blood-­ lead level. It is a fact that exposures are disproportionately greater in lower income children of color (e.g., Filippelli et al. 2015). This impact and the inherent environmental injustices are particularly evident in US cities. Most of the exposure of lead to urban children is from legacy sources that have accumulated from over a century of industrial activity and now reside in surface soil and dust. These now lead-rich deposits continue to be remobilized causing contamination of human (e.g., Laidlaw and Filippelli 2008), food and ecological systems (Zhou et al. 2017).

22.2.8  Understanding the Lead Exposome in Cities Although we do monitor air and water for potential contaminants, there is no similar program to map urban soil geochemistry and thus to identify and eliminate hotspots from this persistent and toxic pollutant. Indeed, we typically resort to analyzing maps of children’s blood-lead levels to find these particular pockets of high lead exposure—in other words, authorities wait until children are exposed so that we can find the source of the pollutant (Taylor et al. 2011). Obviously, this approach fails the gold standard of public health, which is primary prevention. Moreover, such an approach is a backward approach to public health protection, particularly given our understanding of lead toxicity and how we can prevent harm to the most vulnerable section of the population—young children. In summary, a new paradigm of urban lead loading is emerging, one that helps to explain continued chronic lead poisoning and seasonal patterns in blood-lead levels of children. Unlike discrete point sources like lead paint and industrial contact, which are still responsible for most cases of acute lead poisoning, diffuse soil lead is the main avenue for urban lead loading of children. The diffuse soil lead comes from several sources, including leaded gasoline and degraded lead-based paints, but in a sense the source no longer matters—because of the ability of surface soil to retain lead, this becomes the secondary source and the new risk factor for children’s health in lead-loaded cities. Widespread contamination of urban soil creates a different challenge for mitigation of lead risks for children, one based on removing surface soil from human contact. Most mitigation efforts for heavily contaminated soil involved soil removal and replacement, a disruptive and expensive option for controlling lead sources in urban areas (Ottesen et al. 2011; Laidlaw et al. 2017b). Another approach was tested which was simply to cover the contaminated yard soil with about 15 cm of “clean” soil, which in the case of New Orleans came from the nearby Mississippi levee (Mielke et al. 2006). At a fraction of the soil removal cost, this clean soil is simply graded over the old soil layer, hydroseeded, and left to grow a lawn. This approach caps the lead-contaminated soil, removing it from contact by children. The result of

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initial work is a substantial reduction in the blood-lead levels of children living in the affected homes (Mielke et al. 2006). Zahran et al. (2010) report on how nature did this same experiment, seeing substantially lower blood-lead levels for New Orleans children after Hurricane Katrina, due to the capping of much of the lead-­ contaminated soil with flood-related sediments. Mielke et al. (2006) observed that, over the course of several months after treatment, soil lead levels in the treated sites began increasing. This increase was due to dust generated from soil from adjacent, untreated yards and neighborhoods that still had high soil lead concentrations. This finding agrees with results from an urban gardening study in Boston (Clark et al. 2008), which revealed that raised beds experienced substantial increases in soil lead values over as little as 4 years after bed construction, indicating the need to control dust-transported lead at the neighborhood scale. Collectively, these findings not only confirm the new paradigm of diffuse soil lead as a culprit in urban areas, but also indicate that a comprehensive treatment approach is required to provide a long-­ term benefit.

22.2.9  U  rban Gardening as a Vehicle for Education and Action in Lead Remediation An interesting phenomenon has occurred in many larger US cities since 2010—an explosion of urban agriculture and a new awareness of sustainable urban food systems. This movement likely has several contributing causes, including newer availability of large tracts of property in cities after the global recession of 2008–2010, a shift in public perception of cities as desirable places to live and work, and the influx of creative, innovative, and sustainability-focused young people, and their energy and resources, to cities. For example, the number of registered urban farms has increased from 20 to 110  in Indianapolis, IN from 2010 to 2015, a trend which shows no signs of slowing down. Growing food in cities and distributing that food locally have a number of benefits, including enhanced access to fresh and nutritious food, employment of local farmers and distributors, reuse of otherwise vacant land, and generally decreased carbon footprint of the crops. But urban soil has environmental legacies, not least of which is soil lead (e.g., Clark et al. 2008; Chambers et al. 2016). Given its geochemistry and past sources, lead is most enriched in surface soil, and indeed such soil acted to concentrate up to a century of lead deposition in the surface 20 cm of soil, exactly where gardeners work and where plants grow (Oka et al. 2014). In an effort to both inform the public and to provide opportunities for citizen scientists, the Safe Urban Gardening Initiative was launched in Indianapolis, assisted with generous funding from the Indianapolis Foundation. This initiative called on citizens to collect soil samples from several locations in their yards (under the roof dripline, near a roadway, in the garden, or potential garden sites), and deliver these samples to a laboratory for geochemical analysis for lead, other

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anthropogenic metals, and organic matter. The citizens were provided with instructions, and sometimes sampling kits. Data were then provided to the citizens with recommendations on remediation based on the levels of lead that were found, and a guide to safe urban gardening (Fig.  22.10; Filippelli et  al. 2015). The citizens received data and solutions, and the scientists received geolocated samples from a broad expanse of neighborhoods. Although ongoing, with several potential intriguing findings about the fine-scale nature of metal sources and behavior, over 2000 samples have been analyzed and have provided that data to the citizens (Filippelli et al. 2018). Several efforts are underway to flip this equation, and to actively engage with community members to address this gap in quantifying risks of lead exposure through gardening. Some of these approaches are now utilizing citizen science and community-engaged research, which are emerging as effective and powerful mechanisms to collect data and to engage communities to take action to find and reduce personal exposure to contamination in their own homes (e.g., Filippelli et al. 2015; Leech et  al. 2016). Recent examples from soil and dust lead exposure include Indianapolis (as described above; Healthy Cities Project 2018), New Orleans (Lead Lab 2018), Sydney, Australia (VegeSafe 2018), and an emerging global dust network (360 Dust Analysis 2018). While these citizen science and community-­ engaged research programs do not preclude publication in traditional academic journals (Rouillon et al. 2017), they are designed to provide evidence-based advice

Fig. 22.10  Excerpts from an informational guide on urban gardening, and determining and remediating any risks from elevated lead found in soils (Filippelli et al. 2015)

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to participants to help them better manage pollution risks in their home environment. For such citizen-science programs, it is more important that the data can be used to trigger new knowledge and positive changes within local communities. Deeper reach of science and scientists into our wider communities about research that matters to individuals can be accelerated by use of social media platforms, improving the social impact of science. However, while some progress is being made in the low- and middle-income countries that are heavily burdened by contaminants (e.g., Shih 2018), further work is required.

22.2.10  Air Quality Airborne gases and particulate matter continue to be major byproducts of industrialization. The death toll from these emissions has been profound over the past 150 years. From the great London Smog of 1952 that killed well over 4000 people and sickened hundreds of thousands (Wang et al. 2016) to the perennial particulate matter (PM) events that increasingly plague southeast Asia to this day, the human burden of poor air quality has largely been self-inflicted. In the case of the London Smog and similar transient events, the culprit seems to be a combination of emission sources and atmospheric chemical reactions, with recent work even indicating that the atmospheric dynamics of the London Smog event are actually similar to the persistent current long challenges to air quality in China (Fig. 22.11) and south Asia in general—namely, interactions of combustion emissions with atmospheric components. Sulfuric acid is formed from sulfur dioxide released by coal burning, a process that was facilitated by nitrogen dioxide, another coproduct of coal burning, and occurred initially on natural fog (Zhang et al. 2018). This finding indicates that even with reductions in PM, the health burden from other emission sources may remain until those sources are mitigated as well. Collectively, the earlier local event-­ based air quality health crises may have now evolved into persistent, regional crises with multiple drivers, covering broad areas, and persisting for months on end. As the science of PM chemistry and of PM reactivity and physiological responses in lungs has evolved, the PM target of concern has moved from the standard measurement of PM 10 (particulate matter less than 10 μm in aerodynamic diameter) to PM 2.5, and indeed to PM 1 and even smaller (e.g., Wang et al. 2018). Like many other regulatory guidelines (e.g., Henneman et al. 2017), this shift in concern and measurement to smaller PM has largely been due to better techniques for measuring PM, which has in turn provided better fits between the environmental cause and the physiological effect. In a basic sense, the human lung can be thought of as an inverse hydrological system, where flow initiates in the wide bronchia and then moves its way through bronchial tree ultimately to the very narrow alveolar network, where gas exchange occurs. The entire system is at a circum-neutral pH and has multiple mechanisms for capturing any foreign material that enters and moving it up and out of the airways through coughing and sneezing. However, as anybody who suffers from

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Fig. 22.11  Air quality in Beijing in March 2018 on a day classified as “unhealthy for sensitive groups” (photo by Gabriel Filippelli)

seasonal allergies can attest to, this system is quite vulnerable to certain foreign bodies, such as pollen, with reactivity in the upper airways and resultant restriction being the chief physiological response for those affected. In the case of other PM, it also enters airways but the PM 10 is largely restricted to the upper and mid airways because of its larger aerodynamic size. The residence time of these particulates is relatively short and the surface area to mass ratio relatively small, and thus their physiological reactivity is relatively restricted. PM 2.5 and particularly PM 1, on the other hand, are small enough to penetrate as far as the alveoli, and thus have a much longer residence time in the lungs. Furthermore, the smallest PM is of a size that they can and do pass across the lung interface into the bloodstream. Various animal models and human studies have shown that these materials can accumulate in the brain, potentially causing various neurological diseases (e.g., Peters et  al. 2006; Block and Calderon-Garcidueñas 2009; Jayaraj et al. 2017). Nano-sized particulate matter has been identified in the human brain, which confirms that air pollution components reach the brain (Peters et  al. 2006), even penetrating deep into the parenchyma. Furthermore, there is an indication that they can even pass across the placental barrier in pregnant women, entering the fetus before it has even emerged into the world (Calderon-Garcidueñas et al. 2008). For example, it is well known that exposure to fine particulate matter (PM 2.5) from indoor and outdoor combustion is a major cause of premature death (Pope

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et al. 2009), a problem faced by people largely in lower-middle income countries (Landrigan et al. 2017). Indeed, recent work from China indicates that persistent exposure to PM impedes the cognitive level of people as they become older—particularly less educated men (Zhang et al. 2018), which consequently reduces their economic potential. In many cases, the cause of the fine particulate matter is easily solvable but the very homes people live in—namely combustion of wood or coal for heat and fuel in poorly vented and designed devices (e.g., Dybas 2013). This is a classic “wicked problem” because although the solution is a relatively straightforward issue to address with emission regulations and relatively low-cost technologies (e.g., Barn et al. 2018), it is proving resistant to remedy because of organizational and political constraints.

22.3  Other Urban Medical Geology Issues As indicated in the introduction we have discussed some, but not all, of the medical geology issues that can impact urban dwellers. Here we list just a few other issues. For example, in those cities still having active coal-burning power plants and factories, the emissions likely have a deleterious impact on health. Gillmore et al. (2018) discusses the dangers of radon in homes and workplaces. An unknown number of people whose health has been impacted by medical geology issues in rural areas have moved to urban centers to seek treatment. In older buildings asbestos may have been used in pipe insulation, floor boards, ceiling tiles, and in car brake linings. These asbestos fibers may be released through abrasion, deterioration, construction, etc. All of these issues, and more, deserve attention as they potentially can have adverse health impacts on many urban dwellers.

22.4  Conclusions: What Should Be Done? This selective review of some factors that characterize the field of urban medical geology reflects, in general, the major advances in the field but also point to some directions that are currently understudied. For example, we are still treating particulate matter largely as a role in human health. And although it is clear that lead is bad, how is it specifically related to life course disease and well-being? How do single or multiple exposures impact the life course of disease and/or well-being? For example, much focus has been on immediate neurocognitive impacts of lead poisoning in youth, but evidence is emerging related to subsequent violent behavior among adults, potential links to drug abuse, and ultimately build-up of metals in brain tissue that may cause motor neuron disease (i.e., ALS). Among the many remaining questions include:

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1. What is the reactivity of particulates as a function of size, source, and composition in the human lung? 2. What microbial and viral vectors are present in/on particulate matter, and how do they interact with human health? 3. How do mixtures of toxicants interact in modulating human health impact to exposures? Synergistically, antagonistically, agnostically? 4. How do ultrafine particulates enter the blood system and where do they deposit or otherwise affect internal functions leading to disease? 5. How does genetic resistance to toxicant exposure vary among populations, and how might it be modified inter-generationally? 6. How does the human microbiome and changes to it over a lifespan and among a population modify disease susceptible to exposure triggers? 7. How do we balance investments in combatting urban medical geology issues with equity and justice in mind? The list above could be much longer, and indeed should be to encompass the range of unknowns in this area. But one reason that we do not have a clearer roadmap to the major questions in medical geology is that the two sectors that study this issue, geosciences on the geo side and health sciences on the health side, are almost completely separated from each other in terms of funding to support the research, institutes that house researchers, curricula that teach students, and even journals that publish research. It is heartening to see some movement in trying to bridge this gap, with the major US geoscience societies launching the Geology and Health Division (the Geological Society of America) and GeoHealth (the American Geophysical Union) sections for members and meetings, and the new journal GeoHealth explicitly publishing research and policy that link geosciences with human health sciences. We urge more of this, and perhaps starting with how we train our next generation of scientists, which should be inherently linking “natural” processes with human activities and human well-being. By shattering disciplinary boundaries, the true value of geosciences as the critical missing discipline to ensure the health and well-being of humanity will be recognized.

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Filippelli GM, Laidlaw M, Raftis R, Latimer JC (2005) Urban lead poisoning and medical geology: an unfinished story. GSA Today 15:4–11. https://doi. org/10.1130/1052-5173(2005)0152.0.CO;2 Filippelli GM, Risch M, Laidlaw MAS, Nichols DE, Crewe J (2015) Geochemical legacies and the future health of cities: a tale of two neurotoxins in urban soils. Elementa 3:000059. https://doi. org/10.12952/journal.elementa.000059 Filippelli GM, Adamic J, Nichols D, Shukle J, Frix E (2018) Mapping the urban lead exposome: a detailed analysis of soil metal concentrations at the household scale using citizen science. Int J Environ Res Public Health 15(7):1531 Finkelman RB (2016) Medical geology: a classic example of environmental injustice. ISEH 2016, ISEG 2016 & Geoinformatics 2016, Joint International Conference on environment, health, GIS and Agriculture. Galway, Ireland Gillmore, G.  K., Crockett, R.  G. M, and Phillips, P.  S., 2018, Radon as a carcinogenic built-­ environment pollutant. In, Radon, health and natural hazards. G.K. Gillmore, F. E. Perrier, and R. G. M. Crockett, editors. The Geological Society, London, p. 7–34 Gould E (2009) Childhood lead poisoning: conservative estimates of the social and economic benefits of lead hazard control. Environ Health Perspect 117(7):1162–1167. https://doi. org/10.1289/ehp.0800408 Healthy Cities Project (2018). Available at https://www.facebook.com/search/top/?q=healthy%20 cities%20project. Accessed 15 Mar 2018 Henneman LRF, Liu C, Mulholland JA, Russell AG (2017) Evaluating the effectiveness of air quality regulations: a review of accountability studies and frameworks. J Air Waste Manage Assoc 67(2):144–172 Horwell CJ, Baxter PJ (2006) The respiratory health hazards of volcanic ash: a review for volcanic risk mitigation. Bull Volcanol 69:1–24 Hu H, Shine J, Wright RO (2007) The challenge posed to children’s health by mixtures of toxic waste: the Tar Creek superfund site as a case-study. Pediatr Clin 54:155–175 International Labor Organization (ILO) (2010) ILO list of occupational diseases. ILO, Geneva. https://www.ilo.org/wcmsp5/groups/public/@ed_protect/@protrav/@safework/documents/ publication/wcms_125137.pdf Jayaraj RL, Rodriguez EA, Block ML (2017) Outdoor ambient air pollution and neurodegenerative diseases: the neuroinflammation hypothesis. Curr Environ Health Rep 4(2):166–179. https://doi.org/10.1007/s40572-017-0142-3 Jusko TA, Henderson CR Jr, Lanphear BP, Cory-Slechta DA, Parsons PJ, Canfield RL (2007) Blood lead concentrations less than 10 micrograms per deciliter and child intelligence at 6 years of age. Environ Health Perspect 116:243. https://doi.org/10.1289/ehp.10424 Kabata-Pendias A (1995) Trace elements in soils and plants. CRC, Boca Raton, FL Karr C (2008) Reducing childhood lead exposure: translating new understanding into clinic-based practice. Pediatr Ann 37:748–756 Laidlaw MA, Filippelli GM (2008) Resuspension of urban soils as a persistent source of lead poisoning in children: a review and new directions. Appl Geochem 23:2021–2039 Laidlaw M, Mielke HW, Filippelli GM, Johnson D, Gonzales CR (2005) Seasonality and children’s blood lead levels: developing a predictive model using climatic variables and blood lead data from three US cities. Environ Health Perspect 113(6):793–800. https://doi.org/10.1289/ ehp.7759 Laidlaw MAS, Zahran S, Mielke HW, Taylor MP, Filippelli GM (2012) Re-suspension of lead contaminated urban soil as a dominant source of atmospheric lead in Birmingham, Chicago, Detroit, and Pittsburgh, USA. Atmos Environ 49:302–310 Laidlaw MAS, Filippelli GM, Sadler RC, Gonzales CR, Ball AS, Mielke HW (2016) Children’s blood lead seasonality in Flint, Michigan (USA), and soil-sourced lead hazard risks. Int J Environ Res Public Health 13:358 Laidlaw MAS, Filippelli GM, Mielke HW, Gulson B, Ball AS (2017a) Lead exposure at firing ranges—a review. Environ Health 16:34

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Laidlaw MAS, Filippelli GM, Brown S, Paz-Ferreiro J, Reichman S, Netherway P, Truskewycz A, Ball AS, Mielke HW (2017b) Case studies and evidence-based approaches to addressing urban soil lead contamination. Appl Geochem 2:15 Landrigan PJ et al (2017) The lancet commission on pollution and health. Lancet 391:462. https:// doi.org/10.1016/S0140-6736(17)32345-0 Lanphear BP (2017) Low-level toxicity of chemicals: no acceptable levels? PLoS Biol 15(12):e2003066. https://doi.org/10.1371/journal.pbio.2003066 Lanphear BP, Matte TD, Rogers J, Clickner RP, Dietz B, Bornschein RL, Succop P, Mahaffey KR, Dixon S, Galke W, Rabinowitz M, Farfel M, Rohde C, Schwartz J, Ashley P, Jacobs DE (1998) The contribution of lead-contaminated house dust and residential soil to children’s blood lead levels. Environ Res 79:51–68 Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, Canfield RL, Dietrich KM, Bornschein R, Greene T, Rothenberg SJ, Needleman HL, Schnaas L, Wasserman G, Graziano J, Roberts R (2005) Low-level environmental lead exposure and children’s intellectual function: an international pooled analysis. Environ Health Perspect 113(7):894–899 Lead Lab (2018). Available at https://plus.google.com/102811471396098140243. Accessed 15 Mar 2018 Leech TGJ, Adams E, Weathers T, Staten L, Filippelli GM (2016) Inequitable chronic lead exposure: a dual legacy of social and environmental injustice. Fam Community Health 39:151–159. https://doi.org/10.1097/FCH.0000000000000106 Lyles MB, Fredrickson HL, Bednar AJ, Fannin HB, Griffin DW, Sobecki T (2008) Medical Geology: dust exposure and potential health risks in the Middle East. 18th Annual Goldschmidt Conference, Vancouver, Canada, July 13–18. 4 p Manton WI, Angle CR, Stanek KL, Reese YR, Kuehnemann AJ (2001) Acquisition and retention of lead by young children. Environ Res 82:60–80 Mielke HW (1994) Lead in New Orleans soils: new images of an urban environment. Environ Geochem Health 16:123–128 Mielke HW, Reagan PL (1998) Soil is an important pathway of human lead exposure. Environ Health Perspect 106:217–229 Mielke HW, Powell ET, Gonzales CR, Ottesen RT, Langedal M (2006) New Orleans soil lead (Pb) cleanup using Mississippi River alluvium: need, feasibility, and cost. Environ Sci Technol 40:2684–2789 Miranda ML, Kim D, Galeano MA, Paul CJ, Hull AP, Morgan SP (2007) The relationship between early childhood blood lead levels and performance on end-of-grade tests. Environ Health Perspect 115:1242–1247 Morman SA, Plumlee GS (2014) Dust and human health. In: Knippertz P, Stuut JBW (eds) Mineral dust, vol 15. Springer, Berlin, pp 385–409 Morrison D, Lin Q, Wiehe S, Liu G, Rosenman M, Fuller T, Wang J, Filippelli GM (2012) Spatial relationships between lead sources and children’s blood lead levels in the urban center of Indianapolis (USA). Environ Geochem Health 35(2):171–183. https://doi.org/10.1007/ s10653-012-9474-y Needleman H (2004) Lead poisoning. Annu Rev Med 55:209–222 Nevin R (2000) How lead exposure relates to temporal changes in IQ, violent crime, and unwed pregnancy. Environ Res Sect A 83:1–22 Nigg JT, Knottnerus GM, Martel MM, Nikolas M, Cavanagh K et al (2008) Low blood lead levels associated with clinically diagnosed attention deficit/hyperactivity disorder and mediated by weak cognitive control. Biol Psychiatry 63:325–331 Obeng-Gyasi E, Armijos RX, Weigel M, Filippelli GM, Sayegh A (2018a) Cardiovascular-related outcomes in US adults exposed to lead. Int J Environ Res Public Health 15:759–775 Obeng-Gyasi E, Armijos RX, Weigel M, Filippelli GM, Sayegh A (2018b) Hepatobiliary-related outcomes in US adults exposed to lead. Environments 5:46–63 Oka GA, Thomas L, Lavkulich LM (2014) Soil assessment for urban agriculture: a Vancouver case study. J Soil Sci Plant Nutr 14(3):657–669. https://doi.org/10.4067/S0718-95162014005000052

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Ottesen RT, Alexander J, Langedal M, Mikarlsen G (2011) Clean soil at child-care centres and public playgrounds—an important part of Norway’s chemical policy. Chapter 29. In: Johnson CC, Demetriades A, Locutura J, Ottesen RT (eds) Mapping the chemical environment of urban areas. Wiley-Blackwell, Wiley, Chichester, pp  497–520. https://doi. org/10.1002/9780470670071.ch29 Peters A, Veronesi B, Calderon-Garcidueñas L, Gehr P, Chen LC, Geiser M, Reed W, Rothen-­ Rutishauser B, Schürch S, Schulz H (2006) Translocation and potential neurological effects of fine and ultrafine particles a critical update. Part Fibre Toxicol 3:13. [PubMed: 16961926] Pope CA III, Ezzati M, Dockery DW (2009) Fine-particulate air pollution and life expectancy in the United States. N Engl J Med 360:376–386 Roberts JR, Reigert JR, Eberling M, Hulsey TC (2001) Time required for blood lead levels to decline in nonchelated children. J Toxicol Clin Toxicol 39:153–160 Ross M, Nolan RP, Langer AM, Cooper WC (1993) Health effects of mineral dusts other than asbestos. In: Guthrie GD, Mossman BT (eds) Health effects of mineral dusts, reviews in mineralogy, vol 28. Mineralogical Society of America, Washington, pp 361–407 Rouillon M, Harvey PJ, Kristensen LJ, George SG, Taylor MP (2017) VegeSafe: a community science program measuring soil-metal contamination, evaluating risk and providing advice for safe gardening. Environ Pollut 222:557–566. https://doi.org/10.1016/j.envpol.2016.11.024 Roy S, Edwards MA (2018) Preventing another lead (Pb) in drinking water crisis: lessons from the Washington D.C. and Flint MI contamination events. Curr Opin Environ Sci Health 7:34–44 Schnaas L, Rothenberg SJ, Flore MF, Martinez S, Hernandez C et al (2006) Reduced intellectual development in children with prenatal lead exposure. Environ Health Perspect 114:791–797 Selinus O, Alloway B, Centeno JA, Finkelman RB, Fuge R, Lindh U, Smedley P (eds) (2013) Essentials of medical geology, Revised edn. Springer, Berlin, 805 p Shih I (2018) Indonesian scientists embrace preprint server. Nature 553:139. https://doi. org/10.1038/d41586-017-08838-6 Stillwell DE, Gorny KD (1997) Contamination of soil with copper, chromium, and arsenic under decks built from pressure treated wood. Bull Environ Contam Toxicol 58:22–29 Surkan PJ, Zhang A, Trachtenberg F, Daniel DB, McKinlay S, Bellinger DC (2007) Neuropsychological function in children with blood lead levels 1 year) iron toxicity if they plan to consume large quantities of clams from the SCM site and finally that the use of the SCM site for recreational purposes including occasional harvesting and consumption of small amounts of clams and vegetation is not expected to harm the health of the users (ATSDR 2015). While the evaluation was useful for assessing risks to metals exposure for people who eat the specific types of clams and vegetation harvested from the area, there are many other potential traditional and customary resources that were not tested. Fish, shrimp, birds, and eggs are present and harvested by traditional users but were not sampled for the evaluation (ATSDR 2015). The final remedial investigation of the SCM was completed in 2018 (U.S.  Environmental Protection Agency (EPA) 2018d). The EPA ecological risk assessment found the ecological risks are limited to copper in marine sediment in the Tailings Disposal and Depositional Exposure Areas in the Marine Area (EPA 2018d). The site remains open. As a result of these legacy mines, regulations and policy have made strides to improve the development of new resources and the cleanup of existing areas that are impacting the health of all people (Government of Canada 1999; U.S. Environmental Protection Agency (EPA) 2018e). Both the USA and Canada now have requirements for environmental impact assessments before starting a project located on Federal designated land (Canadian Environmental Assessment Agency 2018). Tribes are invited to have representatives present during some of the project discussions representing the Nation-to-Nation status, which is granted to Federally recognized tribal groups, and each Federal agency has different guidelines about the policies. Indian reservations are designated federal rather than state lands, with the legal designation that the land is managed by the federally recognized tribe under the US Bureau of Indian Affairs rather than the state governments in which they are physically located. This designation is complicated when dealing with law and enforcement because states do not have jurisdiction on tribal lands and tribal law officials do not have jurisdiction at the state level outside the reservation. People in general can participate in comment periods for new projects being developed on Federal designated lands. Some tribes have their own Environmental Protection Agencies (EPA) that negotiate with government agencies or corporations before developing projects on their lands. Often these may be stricter than the federal policies because they take into consideration traditional cultural values and customary uses of the land and water. The Navajo Nation, for example, has an EPA “committed to protecting Mother Earth and Father Sky and all living beings through environmental laws and regulations by honoring traditional Dine teachings and culture,” and a vision: “Restoring harmony and a sustainable environment among all living things,”(Navajo Nation EPA 2018).

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24.3.1.4  Transboundary Mining Transboundary watersheds have also been impacted by past mining and mining operations affecting the water and environment by contributing acid mine drainage and other contaminants left by abandoned mining operations to the system. The Alaska-BC transboundary region is home to First Nations in Canada and Tlingit, Tahltan, Haida people in Alaska who live in this area (Rivers Without Borders 2019). One mine that Alaskans as a whole who live near the Juneau area have possibly been exposed to contamination related to acid mine drainage from is British Columbia’s long-abandoned Tulsequah Chief Mine. The mine is an example from this region that is impacting a transboundary water and possibly the fish and wildlife in the drainage. Some of the human health effects from acid mine drainage include skin irritation, kidney damage, and neurological diseases (Moeng 2018). The polymetallic underground mine site is located 64 km northeast of Juneau, Alaska, along the Tulsequah River, in northwestern BC.  The river is a tributary Taku River, an important salmon spawning and rearing habitat. Untreated acid mine drainage has been discharging into the Tulsequah River since at least 1957 (Fig. 24.4) except for a short period of time in 2012, when Chieftain Metals (Chieftain) operated a temporary acid-water treatment plant (Province of British Columbia 2017). Fig. 24.4  Tulsequah Chief Mine exfiltration pond, surface flow from Portal 5200 at the site about 64 km northeast of Juneau, Alaska, Sept. 26, 2016 (Photo Courtesy of SLR Consulting Canada, photo credit: Chris Taylor)

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Chieftain acquired the property in 2010 and received an Environmental Assessment certificate in 2012 (Alaska Department of Natural Resources (ADEC) 2018). Chieftain agreed to address historic acid rock drainage issues as part of re-­ development of the mine, though went bankrupt leaving the site unreclaimed (British Columbia Mine Information 2017). Southeast Alaska tribal groups are worried about damage to subsistence fishing and their health (Brehmer 2018). In November 2018, the BC Ministry of Energy, Mines and Petroleum Resources issued a request for proposals soliciting bids to remediate the mine (Brehmer 2018). The acidic drainage of mines like this potentially affects all people living in the watershed and the whole ecosystem. The long-term human health effects of exposure to water contaminated from acid drainage are dependent on many variables such as the type of metals, what the pathways are such as subsistence foods or drinking water. Some studies are not started until degradation over time of the water quality is to the point where it endangers human, fish, and wildlife health. Sometimes it takes a large disaster to draw attention to the potential health effects of contaminants in watersheds and how they potentially impact the system. One such disaster occurred in August of 2014 when the Mount Polley mine site tailings dam breached (Kohls 2018). This disaster was one of the worst mining disasters in Canadian history. The Mount Polley copper and gold mine is located in south-central BC, 56  km northeast of Williams Lake in the Cariboo region of BC. Approximately17 million cubic meters of effluent water and eight million cubic meters of tailings material flowed into Hazeltine Creek, Polley Lake, and Quesnel Lake (Alaska Department of Natural Resources (ADEC) 2015). Land, water systems, and salmon habitat, all a part of the culture of the Northern Secwepemc were severely impacted or destroyed (Marshall 2018). These water bodies support fish populations that are important to Alaska commercial fisheries even though the upper Fraser River watershed, which these water bodies are a part of, does not drain into Alaska waters (ADEC 2015) (Fig. 24.5). Following the Mount Polley tailings dam breach in 2014, the BC Government sought direct input from Indigenous communities in response to this event. For the first time in BC’s history, representatives from six Indigenous groups were allowed to have a seat at the table in reviewing the health, safety, and reclamation code for mines in BC. This allowed Indigenous representatives to raise issues related to their interests and contributed to the inclusion of new requirements for mines to include Indigenous peoples in emergency planning and annual testing (Association for Mineral Exploration 2018). The collaboration will be important for new mining projects, as several other large mines are being proposed in the Transboundary River region. Having Indigenous stakeholders will be important to be able to address the issues that could affect the health of these communities and help implement testing of relevant traditional ecosystem biomarkers. These could include subsistence foods and medicinal plants, etc. Many of Southeast Alaska’s biggest salmon producing rivers’ headwaters are across the border in Canada (Schoenfeld 2017; Pejan 2018). The development of resources in both the USA and Canada has the potential to impact or even destroy some of the last remaining fisheries in the world, some of which IPNA rely on for their way of life and cultural health (Gullufsen 2017; Pejan 2018; Earth Justice 2019) and commercial fisheries depend on economically.

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Fig. 24.5  Aerial photo view of the Mount Polley copper and gold mine tailing dam breach in south-central BC, Canada. Approximately17 million cubic meters of effluent water and 8 million cubic meters of tailings material flowed into Hazeltine Creek, Polley Lake and Quesnel Lake in Aug. 2015 (Photo credit: Jamie Heath, Terrasaurus Ltd)

Some of the proposed mines which would impact multiple First Nations and Alaska Native peoples waterways and major fisheries include: the Kerr-Sulphurets-­ Mitchell (KSM) project, one of the world’s largest proposed open-pit copper-gold-­ silver mines located within 30 km of the BC-Alaska border on Sulphurets Creek, a tributary of the fish-bearing Unuk River, which flows into Misty Fiords National Monument in Alaska (Rivers Without Borders 2013); the proposed Ruddock Creek lead and zinc mine located 155 km NE of Kamloops, BC (Imperial Metals 2019) which threatens some of the most important watersheds and salmon runs in Secwepemc territory, including the Adams River run, one of the world’s largest remaining sockeye salmon (Darwish 2014); and the proposed Pebble Mine, a large copper-gold-molybdenum porphyry deposit consisting of two contiguous deposits of approximately 7.4 billion metric tons resource combined located on state land in the Bristol Bay Region of southwest Alaska (Alaska Department of Natural Resources (ADEC) 2019). The site is at the headwaters of the Nushagak and Kvichak rivers which supports the largest sockeye salmon run in the world, producing approximately 46% of the world’s wild sockeye harvest (U.S. Environmental Protection Agency (EPA) 2014a). Pebble Limited Partnership has applied for federal permits to develop a portion of the deposit as an open-pit mine, along with an associated transportation corridor, Amakdedori port facility, and natural gas pipeline (ADEC 2019). It is projected that mine waste from the largest pit could fill roughly 3900 professional football stadiums (American Rivers 2018). These are just a few examples of mine-related issues that impact or may potentially impact water that could affect people, plants, and animals in our ecosystems.

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There are many abandoned mine and mill sites that are located on or near Indigenous Peoples’ lands that are still in need of remediation. The ability to clean up these sites is expensive, and funding is hard to generate for many projects with Tribal resources. Some sites are eligible to receive Federal grants which are competitive and may need matching funds. When the contamination comes from lands outside the tribal lands, then cleaning up the sites must be approached through state and/or federal agencies. These agencies have to prioritize their budget allocations and if the problem is not affecting a large population or depending on the type of contamination the projects may be of lower priority for funding. The long-term effects from these mining operations on human, plant, and animal life are not always measurable due to lack of long-term data collection in the western scientific method. The effects can potentially last for decades or much longer. The stress on cultural preservation and lifestyle with impending development is a serious health concern or social determinant for IPNA along with recognized environmental pathways of contaminants. When large projects are being developed, there is often an influx of people to get the projects operational. This impacts communities in these areas, which are generally rural with not much other industries. The amount of crime and domestic violence increases substantially in these areas (Deer and Nagle 2017), and water is also impacted by greater consumption and more chance of degradation by the facilities and infrastructure that accompany development. Environmental grief or Solastalgia is a relatively new concept developed to give greater meaning and clarity to environmentally induced distress (Albrecht et al. 2007). As opposed to nostalgia which is defined as the melancholia or homesickness experienced by individuals when separated from a loved home or environment, solastalgia is the distress that is produced by environmental change that impacts people while they are directly connected to their home environment (Albrecht et al. 2007). This concept is likely what is being felt by people in many parts of the world, especially when there are projects being proposed or when passed unreclaimed development has left contamination in their environment. When megaprojects such as the Pebble Mine in Alaska are proposed, there are always those who are in favor and those who are not. Economically, in this lifetime for many of the people Indigenous or not, development of the mine will benefit some people by providing needed income. If there is a failure of the tailings dam in the future of the operation of the project, the salmon runs could be lost. This loss would be a loss to the culture of the Indigenous people who rely on the salmon, the commercial fishing business, all Alaskans and to an integral part of the ecosystem for the whole world.

24.3.2  Oil and Gas Sourced Contamination Oil and gas sourced contamination affects all humans, watersheds, and wild and plant life that forms our ecosystems. Many people have been impacted by oil and gas infrastructure whether in the planning, full production, accidents, and potentially decommissioning of old systems. Oil and gas pipelines have contributed to contamination of water sources by spills, leaks, and by chemicals such as defoliants

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that are applied to the corridors of aboveground pipelines (Alaska Department of Environmental Conservation (ADEC) 2005; Department of Environmental Quality 2015). Fuel tanks, whether stored aboveground or below, have been sources of contamination affecting water and the environment when they leak or degrade. Oil spills from tankers and offshore drilling have impacted waters, people, and wildlife. 24.3.2.1  Unconventional Gas and Oil Extraction Unconventional gas and oil extraction have impacted water and the environment by the large amounts of water that are used in the production and the disposal of the wastewater and products from the different extraction processes (Vengosh et  al. 2014). Many of the chemicals and metals that are introduced with the tailings (oil sand extraction), holding ponds (coal bed methane), injection wells (hydraulic fracking and oil sand extraction), discharge of fracking waste into rivers and streams, and drilling may migrate into drinking water wells that may potentially affect the health of humans (Vengosh et  al. 2014; U.S.  Environmental Protection Agency (EPA) 2016; Bushkin-Bedient et al. 2019). Unconventional oil and gas extraction can deplete streams and aquifers in ways that contribute to water stress and water scarcity (EPA 2016) which can impact health. 24.3.2.2  Oil Sands in Canada Development, processing, and tailings associated with oil sands in Alberta have impacted the water and the environment (Frank et  al. 2014; Leahy 2019). The Athabascan River, its tributaries, and groundwater have been degraded from leaking tailings ponds and through aerial emissions from the process of upgrading the bitumen to synthetic crude oil which involves coking, coke combustion, and production of wastes and fly ash (Kelly et al. 2010; Frank et al. 2014). The increased greenhouse gas emissions are significantly larger than for conventional crude oil and are contributing to global warming and the enhanced greenhouse effect. Oil sands operations currently emit roughly 70 Megatons per year and account for one-quarter of Alberta’s annual emissions (Government of Alberta 2019b). The Alberta oil sand deposit is the largest known oil sand deposit in the world with a proven equivalent of 168.9 billion barrels of oil reserves, the most of any country in North American, and the third of any country in the world (BP 2018). The USA is the largest importer of this oil from Canada (BP 2018). The oil sands are strip mined in the Athabasca area where the deposit is approximately 75  m deep. As of 2017, 767  km2 out of 4800  km2 surface mineable area had been cleared or disturbed (Government of Alberta 2019b). Other areas of the deposit are processed in situ underground similar to fracking, involving injection of steam and proprietary other chemicals for enhanced recovery of the product (Giacchetta et al. 2015; Hedges 2019). The tailings ponds associated with the mining have caused migrating birds that land on them to die in huge numbers. So many birds have been killed that the Canadian

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government has ordered extraction companies to use noise cannons at some of the sites to scare away arriving flocks (Government of Alberta 2019b; Hedges 2019). First Nations and Métis settlements in Alberta are being affected by the oil sands’ development, suffering consequences that range from land rights, health issues including increased cancers, intergenerational trauma, degradation of water and land, to loss of livelihood (Smith 2009; IEN 2018; Hedges 2019). The Beaver Lake Cree Nation, Treaty No. 6 Area, maintains the boom in oil sands extraction is destroying their hunting and fishing lands. They claim that caribou, elk, moose, deer, and other animals are disappearing or infected with diseases, fish stocks are damaged by water pollution, and plants used for traditional medicine are under threat (Smith 2009; Hedges 2019). The water is no longer safe for human consumption in some parts of northern Alberta, and drinking water has to be trucked in for the Beaver Lake reserve (Hedges 2019). 24.3.2.3  Oil Spills: Exxon Valdez Example One of the worst oil spills in US history was the Exxon Valdez oil spill (EVOS) in 1998 which occurred in Prince William Sound, Alaska (Shigenaka 2014). In just over a few days, the total amount of oil spilled was estimated to be 11 million US gallons (9,159,416 Imperial Gallons) of crude oil spilled. Eventually, oil from the spill affected more than 1600 km of Alaska’s remote and rugged coastline (Shigenaka 2014). The oil killed and injured, seabirds, sea otters, harbor seals, bald eagles, orcas and marine life, and local Alaska Native villages were severely impacted. Alaska Native villages in the area most impacted by the oil spill were highly dependent on commercial fishing and subsistence harvests. The EVOS directly threatened the long-term survival of these communities. The herring and crab have yet to recover, there is still oil on the beaches and Exxon ultimately paid only one-tenth of the original $5 billion judgment won in 1994 (Lankard 2017). 24.3.2.4  Oil and Gas Pipelines Water sources that were contaminated along pipelines have possibly left a legacy of poor health including a suspected increase in cancers in some communities and other diseases which may have links or associations to multiple contamination sources (Godduhn et  al. 2013). The contamination can affect all people who use these waters. The impossibility of measuring historic exposure levels for anyone who might not have a political voice does not negate the history of environmental injustice. Some oil and gas pipelines have been built across or near Indigenous Peoples’ lands or traditional lands, without consultation of the tribes (Tauli-Corpuz 2017). The Trans-Alaska pipeline is approximately 1300 km long and connects the oil fields of Prudhoe Bay in northern Alaska, with the harbor at Valdez, to the south (Ray 2008). The pipeline was built in 1968 after oil was discovered in Prudhoe Bay. The pipeline had to be built with about half of the length aboveground to prevent the

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heated oil in it from thawing the permafrost and to allow wildlife to pass more easily under it (Ray 2008). Portions of the pipeline were also buried to facilitate the movement of wildlife. Special construction measures to dissipate heat buildup in permafrost included installing devices around pipeline-support trestles and building bridges for the pipeline across rivers and streams to avoid burying the pipeline at those locations (Ray 2008). The 1.2-m pipe is boosted by pumping stations situated along its length which ensure a constant flow of roughly 6 km per hour (Ray 2008). There have been minor leaks and spills along the length of the pipeline and at some of the pump stations. The worst spill associated with the pipeline was in 2006, when a transit pipe at British Petroleum (BP)’s Prudhoe Bay facility ruptured. More than a quarter million gallons (one million liters) of oil spilled onto the tundra, and Prudhoe Bay production was halved as engineers spent months replacing corroded pipe (Ray 2008). In Alaska, the Haines-Fairbanks Pipeline is another example of a pipeline that potentially impacted water sources in Canada and Alaska. The pipeline was an important logistical asset during the Cold War (Hollinger 2003). The 1007 km pipeline system extended from the Haines Terminal in SE Alaska crossing 483  km through Canada to the Fairbanks Terminal at Fort Wainwright to transport petroleum products to two military bases in interior Alaska (ADEC 2005). The pipeline operated from 1954 to 1973 though even after major sections of the pipeline were deactivated, the tank farms at Haines and Tok continued to be used for fuel storage. Fuel spills contaminated the environment. The long-term effects of these impacts on subsistence resources, Alaska Native and Canadian Indigenous peoples’ traditional lifestyles and health, and the health of pipeline employees are important subjects that are beyond the scope of this chapter (Hollinger 2003). There also was possible contamination through the aerial spraying of chemical defoliants along the corridor. There was concern that the defoliants polluted vegetation, which was in turn consumed by people or wildlife. There are also two accounts of Klukshu Indian Village residents in Canada being directly hit by the herbicide during the spraying (ADEC 2005). The village was adjacent to the pipeline right-of-way. A 1994 study investigated the Klukshu Indian Village’s exposure to the defoliants (Hollinger 2003). The author concluded that there were hazardous levels of dioxin contamination in the soil. The long-term, overall effects of the chemical defoliants along the entire corridor are not fully known (Hollinger 2003). Modern oil and gas pipelines are being proposed in the USA and Canada to supply the demands of foreign and domestic needs which potentially may impact IPNA and other people. Many of these proposed pipelines have to be negotiated with the Indigenous peoples because the pipelines whether new or extensions of existing pipelines either cross Indigenous lands or may affect the lands and waters of IPNA. Many of these are environmental justice issues. In the USA, the development of the North Dakota Pipe Line (NDPL) is one example of an oil pipeline with possible contamination and environmental justice issues. The Lakota phrase “Mní wičhóni,” or “Water is life,” became a national protest anthem in the USA during the almost year-long struggle to stop the building of the Dakota Access Pipeline (DAPL) under the Missouri River in North Dakota

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(LaPier 2017). This approximately 1886 km of 76 cm diameter pipeline was being built to bring crude oil from the Bakken and Three Forks production areas in North Dakota southeast to Patoka, Illinois, for supply to major refining markets (Dakota Access LLC 2014). The DAPL was being protested because of its potential to pollute community water supplies, damage sacred tribal lands and historical sites of the Standing Rock Sioux Reservation if it leaked or was damaged (Dalrymple 2016). A previously proposed route for the pipeline had it crossing the Missouri River north of Bismarck, North Dakota, according to a document filed as part of the permitting process (Dakota Access LLC 2014). The eventual route that was decided on was south of the North Dakota capital, just upstream of the Standing Rock Sioux tribe’s reservation (Thorbecke 2016). Before its completion, the pipeline was temporarily halted when a federal judge said that the US Army Corps of Engineers (ACE) failed to perform an adequate study of the pipeline’s environmental consequences when it first approved its construction and ordered a new report on its risks (Meyer 2017a). In a 91-page decision, the judge cited the ACE’s study of the impacts of an oil spill on fishing rights, hunting rights, or environmental justice as particularly deficient (Meyer 2017a). Part of this decision was about the methodological grounds used by the Corps’ review process in the buffer zone or distance from the pipeline that they based their report. According to federal regulation, every major project constructed near a poor community, community of color, or American Indian reservation must be studied on environmental justice grounds (Bullard 2004). In a memo regarding the matter, the ACE stated that no affected group lived within a half-mile (800 m) of the pipeline route, which was technically correct. The Dakota Access pipeline runs 0.89  km north of the Standing Rock Sioux reservation. (Meyer 2017a). With a change in the US administration, an executive order expediting the environmental review and approval process was ordered to allow the pipeline to proceed (Meyer 2017b). The pipeline began service on June 1, 2017 (Kirby 2017). Though the pipeline does not cross the existing reservation lands, it does cross the area covered by the Fort Laramie Treaty. The tribe’s subsistence hunting and fishing, sharing their harvest with elders and the cultural norms that remain intact, would be jeopardized by an oil spill from DAPL (Faith 2018). There are also pipelines that are being proposed in Canada such as the Trans Mountain expansion (TMX) which would be a pipeline from Edmonton, Alberta to Burnaby, BC, which has 117 Indigenous groups along the pipeline corridor potentially affecting the groundwater and sacred sites of some of these nations (Markusoff 2018). The TMX is being proposed to diversify Canada’s export market access for oil to markets in Washington State and northeast Asia (Japan, China, South Korea, and Taiwan) and to secondary markets in the USA, including Hawaii (Natural Resources Canada 2019). On August 30, 2018, the Federal Court of Appeal quashed the approval of the TMX project on two grounds: (1) the National Energy Board erred in its decision to exclude consideration of marine shipping impacts; and (2) Canada failed to properly execute its legal duty to consult with Indigenous Peoples. October 3, 2018, the Government of Canada announced that it would be reinitiating consultations with all 117 Indigenous groups potentially impacted by the project (Natural Resources Canada 2019).

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The Energy East Pipeline was a 4500  km pipeline proposed by TransCanada Limited, to carry 1.1  million barrels of crude oil per day from Alberta and Saskatchewan to refineries in Eastern Canada (Major Projects Management Office 2017). The company also proposed to construct a 279  km Eastern Mainline gas pipeline between Markham, Ontario, and Brouseville, Ontario. Both projects would have included portions of existing pipeline and constructed new portions of pipeline and marine terminals. In 2016–2017, Natural Resources Canada sought feedback from Indigenous groups on a both of these projects for participation and offered participant funding to Indigenous groups potentially impacted by the projects to support their review of the draft consultation approach and to facilitate their participation in early Crown consultation activities for these projects (Major Projects Management Office 2017). TransCanada Limited withdrew its application for review by the National Energy Board project and ended the project in October of 2017 (Major Projects Management Office 2017). The Premier of New Brunswick, along with some other premiers and federal politicians, tried to revive the proposed pipeline in late 2018, to get more western crude to refineries in Eastern Canada and for export to foreign markets (Bissett 2018). Another gas project which met opposition from many First Nations peoples would have carried 34.3 million cubic m of natural gas about 1200 km from the Beaufort Sea to northern Alberta (Dokis 2010). Due to economics the falling price of natural gas the Mackenzie Gas Project was no longer profitable and ended in 2017 after 50  years of development processes (Environmental Justice Atlas 2018). Northern Gateway Pipelines Project was another large project with environmental concerns for many First Nations peoples. In 2012, public protests and social media communications similar to the NDPL involving thousands of people from across Canada were held in opposition to the development of the Alberta oil sands and the Northern Gateway Pipeline (White et al. 2014). At stake were the health and rights of the local First Nations people and the preservation of the national Great Bear Rainforest (Natural Resources Canada 2017b). The Canadian Government determined that the project was not in the public interest because it would result in crude oil tankers transiting through the sensitive ecosystem of the Douglas Channel, which is part of the Great Bear Rainforest and in 2016, quashed the 2014 decision by the previous government which had approved the proposal (Natural Resources Canada 2017b). In making this decision, the Government considered the Joint Review Panel Report, the views of Indigenous communities and those of other Canadians (Natural Resources Canada 2017b).

24.3.3  Contaminated Sites Data Bases The federal governments of the USA and Canada have contaminated sites and brownfields programs specific to contaminated sites on IPNA lands (U.S.  Environmental Protection Agency (EPA) 2014b; Indigenous and Northern Affairs Canada 2016). Because Alaska has over 40% of the federally recognized tribal entities there are many contamination sites that have impacted or continue to

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impact the water used by Alaska Native peoples. In Alaska, there are about 7700 documented contaminated soil and water sites listed with the ADEC Contaminated Sites Program (Alaska Department of Environmental Conservation (ADEC) 2018). Approximately 70% of these have been closed leaving about 2300 open or active sites (Fig. 24.6) in the database (ADEC 2018). Most of the active contaminated sites listed with the ADEC Contaminated Sites Program (74%) are from releases of petroleum products and many have additional contaminants, including volatile and semi-volatile compounds, metals, PCBs, and other contaminants (ADEC 2018). Remediation is very expensive often requiring removal of soils and materials to acceptable depositories. Sometimes materials are shipped on barges to recycling or designated hazardous disposal sites in the Pacific Northwest (ADEC 2018). Some of these contaminated lands were conveyed from

Fig. 24.6  Map shows the contaminated sites in Alaska. The orange (exaggerated width) lines show the location of the TransAlaskan Pipeline and also the Haines/Fairbanks Pipeline which crossed through British Columbia, Canada. Data was from the Alaska Department of Conservation database. Many properties have multiple site locations associated with them and some may only have a single leaky storage tank or spill (Map prepared by the author)

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the federal government to Alaska Native Corporations under ANCSA and collaboration has continued with Alaska regional and village Native Corporations and federal agencies to seek solutions to contaminated lands and water (ADEC 2018).

24.3.4  Formerly Used Defense Sites Formerly used defense sites (FUDS) are found across the US states and territories and often included in contaminated sites databases. More than 10,000 potential FUDS properties exist in the USA ranging from less than an acre to hundreds of thousands of acres in size (U.S. Army Corps Of Engineers 2015). The sites can be found in industrial or residential areas as well as on federal, tribal, or state properties. When the military closed and abandoned facilities, they left behind equipment and supplies which included containers of hazardous substances such as brake fluid; fuel drums containing petroleum products; anti-freeze; containers of Polychlorinated Biphenyls (PCBs); above- and underground fuel tanks; and transformers containing PCBs (Hogan et al. 2006). In the USA, Alaska is ranked third for the number of properties eligible for cleanup under the Formerly Used Defense Sites (FUDS) program (Williams and Cravez 2018). There were over 600 active FUDs in Alaska which made up about 30% of the ADEC Contaminated Sites database in 2019 (Alaska Department of Environmental Conservation (ADEC) 2018). Many of the properties were contaminated during World War II, or during the Cold War, when the long-term effects of chemicals were not understood, and the accepted means of disposal was to bury or abandon anything that was too expensive to transport out of Alaska (Williams and Cravez 2018). Many of these sites are located on Alaska Native Corporation lands close to villages and traditional hunting and fishing grounds. For example, there are about two dozen FUDS in the Norton Sound region (Hogan et al. 2006).

24.3.5  Pulp Mill Industry Pulp and paper mills have impacted waters and health of many people including IPNA.  In Canada, the Dryden Chemical Company pulp mill, in Dryden Ontario dumped 2–4.5 kg of mercury effluent into the English-Wabigoon river system daily between 1962 and 1970, totaling more than 10 tons (Mosa and Duffin 2017). The Canadian government ordered the company to cease mercury dumping by March 1970 and estimated it would take 12  weeks before the mercury levels lowered in local fish (Mosa and Duffin 2017). The mercury spread throughout the river system affecting both the Asubpeecho-seewagong (Grassy Narrows) and Wabaseemoong (Whitedog) First Nations (Schreiner 2016). For many generations, these people relied on the river as a source of drinking water and consumed a diet high in fish from the river (Schreiner 2016). In 1975, at the request of First Nations band

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councils, several Japanese researchers knowledgeable about the effects of methylmercury, came to Canada and found that Minamata disease was already evident, although symptoms were mild (Mosa and Duffin 2017). Minamata disease is methylmercury (MeHg) poisoning that occurred in humans who ingested fish and shellfish contaminated by MeHg discharged in wastewater from the Chisso chemical plant. In 1956, Minamata disease was first officially “discovered” in Minamata City in the south-west region of Japan’s Kyushu Island (Harada 1995). The chemical speciation of mercury determines its mobility and toxicity (Ullrich et  al. 2001; Beckers and Rinklebe 2017). MeHg can affect human health particularly via the consumption of contaminated fish since MeHg is a potent neurotoxin that bioaccumulates (Ullrich et al. 2001). Between 2004 and 2014, Japanese researchers continued the research which showed that Minamata disease was evident in the First Nations peoples from this area. The research showed that many of the original cohorts had died and that young people had symptoms of mercury poisoning in the follow-up research, showing that contamination has affected three generations of people in the area (Schreiner 2016; Brusser and Poisson 2016; Mosa and Duffin 2017). A study, authored by five mercury experts released on Feb. 28, 2017, reported that tests showed mercury levels downstream of the Dryden Chemical Company were 130 times higher than upstream locations suggesting that the area is still contaminated from the chemical releases that occurred in the 1960s (Mosa and Duffin 2017). The area still has not been cleaned up which is partly due to the government and First Nations representatives fearing more contamination of the watershed if the sediments were disturbed (Brusser and Poisson 2016). The Government of Canada contributed more than $9 million dollars in compensation to First Nations members affected by mercury contamination of the English-Wabigoon River system from the pulp mill for economic and social development initiatives (INAC 2005). To be compensated, First Nation residents seeking benefits can have a neurological assessment done by a doctor who determines the severity of neurological symptoms based on a point system (INAC 2005). This location could be a potential area for a medical geology study with collaboration among other scientists and people living in this area to explore the pathways for the mercury and the environment for the methylation of mercury to occur. Sediments and pore fluids might be sampled as well as fish and aquatic life for the presence of mercury and its speciation. Mercury speciation, controls on MeHg production, and bed sediment-pore water partitioning of total Hg and MeHg could be examined. There could be residual organic material from the pulp mill effluents remaining in the sediments. Sediment organic matter has been shown to limit mercury methylation in estuarine ecosystems, as a result, it is often described as the primary control over MeHg production (Schartup et  al. 2013). The anoxic pore spaces of the sediments of the stream bed, the overflow bank deposits, island stream bars, etc. could be sites where organic material may be supplying the necessary nutrients for sulfate-reducing bacteria (SRB) which are known mercury methylators (Tauli-Corpuz 2017). Both the mercury and the organic material were contributed to the watershed by effluents dumped into the river system. Whether or not these materials are still coexisting and with SRB could be explored.

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Pulp and paper mills operated in southeast (SE) Alaska from 1957 to the 1990s (Division of Economic Development 1997). Sawmills were needed to supply the wood products to the pulp mills in SE Alaska. Both the sawmills and pulp mills had a large economic value for the state of Alaska and to Alaska Natives Corporations including the Sealaska regional corporation which has more than 22,000 Tlingit, Haida, and Tsimshian people of SE Alaska who are shareholders (Sealaska Corporation 2019). The Alaska Pulp Corporation (APC) was the parent company for the Sitka pulp mill and Wrangell sawmill in SE Alaska (Division of Economic Development 1997). Louisiana Pacific was the parent company for the Ketchikan pulp mill and sawmill and a port and sawmill in Metlakatla that operated from 1979 to 1997 to ship products to locations including Japan which was the main buyer for much of the pulp industry in Alaska (Division of Economic Development 1997). Sitka and Ketchikan were the main producing pulp mills in SE Alaska and employed many people in Alaska for nearly 40 years. The pulp mills in southeast Alaska used chlorinated pulp bleaching processes which were not recognized as environmental and health concerns when they were first operating. Later significant environmental concerns developed in the USA and Europe with regard to the dioxins released during chlorinated pulp bleaching processes (Division of Economic Development 1997). Both the former Alaska Pulp Corporation—Sitka mill site and the Ketchikan pulp mills in southeast Alaska are listed in the ADEC contaminated sites database with contaminants including heavy metals and dioxin releases (Division of Spill Prevention and Response 2018). The Ketchikan pulp mill became a Superfund site which was cleaned and up and is under long-term monitoring and institutional controls (U.S. Environmental Protection Agency (EPA) 2017c). Much of the SE Alaska population, both native and non-native consume a large proportion of local seafood from the areas. Long-term health effects of early dioxin exposure related to pulp mill effluents and bioaccumulation have not been specifically studied in this area. Epidemiologic studies have been conducted on different diseases and chronic illnesses though few have examined the relationship between exposures to environmental contaminants in SE Alaska. This is likely due to the lack of accurate exposure data in Alaska. Data from studies have shown that SE Alaska has the highest rate of some diseases like systemic lupus erythematosus (Boyer et al. 1991; Ferucci et al. 2014), rheumatoid arthritis (Boyer et al. 1991), auto-immune hepatitis (Hurlburt et al. 2002) breast cancer (Carmack et al. 2015), prostate cancer (second highest behind Kodiak Island) (Carmack et  al. 2015) in Alaska Natives compared to the non-Alaska Native population and in Parkinson’s Disease (Willis et al. 2010; Trimble 2016) and non-Hodgkin lymphoma (Carmack et al. 2015; Alaska Cancer Registry 2017) for Alaska Natives and for the whole state population. Though not specific to Indigenous people, an epidemiologic study of pulp and paper workers in British Columbia suggested that long-term work in the pulp and paper industry is associated with excess risks of prostate and stomach cancers and all leukemias (Band et al. 2001). Also a geospatial study investigated the relationship of spatial patterns of ovarian cancer incidence rates with toxic emissions from pulp and paper facilities using data from the EPA’s Toxic Release Inventory in the

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lower 48 states of the USA (Hanchette et al. 2018). The study found counties with high ovarian cancer rates were associated with counties with large numbers of pulp and paper mills, supporting a possible role of waterborne pollutants from pulp and paper mills in the etiology of ovarian cancer (Hanchette et  al. 2018). Research related to long-term health effect from effluents in water from pulp mills is lacking. Pulp mills have contributed to air and water pollution in both the USA and Canada.

24.4  Climate Change Climate change affects the whole world and the changes related to water are impacting all people. The topic of climate change is covered in another chapter of this textbook, but this section will focus on a few of the issues related to water affecting Alaska communities, though the Canadian Arctic would have similar issues. For tribes in the southwestern USA, reductions in rainfall and prolonged drought impact available drinking water and affect agricultural and ranching practices (Navajo Nation Department of Water Resources 2019). Subsistence practices in the southwest are being disrupted due to the influx of invasive species from prolonged drought (Norton-Smith et  al. 2016). Subsistence practices across North America and the world are changing as a result of climate change for all people who rely heavily on subsistence. Traditionally people collected things at specific times of the year. With climate change, these Indigenous calendars are changing, with some things being harvested earlier and hunting also varying (Kassam et al. 2018). Communities in coastal areas are being affected by coastal erosion and sea-level rise, which threaten vital community infrastructure and lead to forced displacement and relocation (Brubaker et al. 2011; Norton-Smith et al. 2016). For example, the village of Newtok, a growing 350-person coastal village fronting on the Ninglick River in western Alaska has been moving to a new site at Mertarvik, after 20 years of planning. In the summer of 2019, 13 new houses were being built on the volcanic rock of Nelson Island, 12 miles from Newtok. They also hoped to finish a community center that might serve as a school in the fall. Newtok residents, US Marines, people from ANTHC, and workers for Native-owned contracting companies were the construction crews (Rozell 2019). Many rural Alaska villages developed over the last several decades with little thought about economic development and the long-term costs for energy, transportation, water and sewer, freight delivery, air access, and other community infrastructure. Newtok’s relocation to Mertarvik presented a unique opportunity to create a new model for a sustainable Alaska Native Village based on current technology and the lessons learned from past decades of community development activity (DCCED 2011). There are 31 Alaska Native communities that have been identified by the US General Accounting Office as being impacted significantly by climate change, with 12 of these requiring some form of relocation, these communities are considered to be environmentally threatened (ANTHC 2018). Once identified as in need of relocation, federal agencies are cautious about making substantial investments. As a result, places like Newtok and

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Kivalina, both in stages of community relocation, housing, electric power production, water and sewer, boardwalks and roads, solid waste facilities, and other basic community infrastructure are slow to be replaced (ANTHC 2018). To compound matters, climate impacts continue to destroy millions of dollars in infrastructure adding stress to the already stressed. Slow-moving disasters such as climate change are not considered impactful enough for federal response and financing, so these communities are challenged with finding alternative solutions (ANTHC 2018). In the Arctic, the permafrost layer serves to protect the water and soil from mining wastes and landfills. As northern regions continue to warm, the permafrost is beginning to thaw (Hinzman et al. 2005). Landfills (dumpsites), contaminated sites, tank farms, boneyards of worn-out vehicles and heavy equipment, and places where historical military or mining activity occurred near a community may be sources of hazardous chemicals, such as PCBs, chlorinated solvents, heavy metals, pesticides, and petroleum products (Division of Environmental Health 2018). When these sites are along rivers, streams, and coastline, erosion may cause hazardous substances to be released into the ocean and the state’s rivers affecting Alaska’s waters, fish, wildlife, and people. Dump sites are already being affected in many villages. Some dumps that were buried are now eroding into the nearby water bodies (Fig. 24.7), and the contents of these dumps are contributing to pollution of surface water in coastal Alaska Native communities (Alaska Department of Environmental Conservation (ADEC) 2019). These changes increase the risk of infectious disease by damaging and disrupting water and sanitation infrastructure for communities in the Arctic and Subarctic (Brubaker et al. 2011).

Fig. 24.7  Alakanuk South Side Dump Site eroding into Alakanuk Pass in 2012 (Photo credit: Alaska Department of Environmental Conservation)

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Food and water security are also being impacted by changes in the water. IPNA living near lakes, rivers, and streams experience changes in water temperature and in streamflow or lake depth which may increase the severity of existing declines in salmon and other culturally important species (Norton-Smith et  al. 2016). In the Arctic, thawing of the permafrost decreases food security in traditional underground ice cellars where foods such as bowhead and beluga whale meat are stored when the cellars that previously remained frozen year-round thaw in the summer months (Brubaker et  al. 2011). The permafrost and ice melt makes it more difficult and sometimes dangerous for hunters to access traditional grounds and is changing the migration patterns of certain species (Norton-Smith et al. 2016). Thawing of the permafrost may increase the amount of mercury available in the environment (Schuster et al. 2018). Permafrost has been a sink for mercury, storing roughly 15 million gallons. This is at least twice the amount contained in the oceans, atmosphere and all other land combined (Schuster et  al. 2018). It is known that mercury is a bioaccumulator and concentration in living tissue increase in birds, fish, sea mammals, and humans going up the food chain, even in areas thousands of miles from pollution sources (Kirk et al. 2012). Indigenous people across the Arctic rely on these sources for subsistence and there is growing concern about the levels of mercury and other pollutants that are accumulating in traditional foods. Data collected over 20 years from eight Arctic countries showed that the highest levels of total mercury were observed in the blood of women of childbearing age (including pregnant women) from Nunavik in Canada in a study that was part of the Arctic Monitoring and Assessment Program (AMAP), one of the six working groups established under the Arctic Council (Gibson et al. 2016). The rate and amount of mercury that will be released from the soils as the permafrost thaws are not known but will be a factor related to climate change that will affect water quality (Schuster et al. 2018).

24.4.1  Persistent Organic Pollutants In the Arctic, many of the IPNA communities lead a traditional lifestyle of hunting and fishing. For example, the traditional Inuit diet consists largely of fish and sea mammals. A study done in the 1980s identified widespread Alaska Native exposure to organochlorines that originated outside of the Arctic (Rubin et al. 2001). These persistent organic pollutants (POPs) were not derived from industry in the area but were carried northward by atmospheric and ocean currents, and accumulated in the bodies of fish, seals, and other animals (Rubin et al. 2001). The Arctic Monitoring and Assessment Program (AMAP) has been collecting data for over 20 years and finds that certain contaminants, such as perfluorinated compounds and polybrominated diphenyl ethers, are still increasing in Arctic populations (Gibson et al. 2016). Work done in Canada as part of the International Polar Year Inuit Health Survey in 2007–2008, showed that metal and POP body burdens commonly exceed exposures observed in the general population of Canada (Laird et al. 2013). In Alaska, in the

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Yukon-Kuskokwim Delta Region in response to the local residents’ concerns over the effects of bio-accumulated chemicals on their children, the Maternal Organics Monitoring Study (MOMS) was developed (ANTHC 2019a). The main findings of the MOMS thus far, indicate that the overall benefits of a subsistence diet outweigh the risks from exposure to environmental pollutants (Anwar et al. 2016). The National Tribal Water Center (housed at ANTHC) developed a program called Project Coyote Water to find contaminants on Tribal lands. It is collaboration between the National Tribal Water Center (NTWC) and the Center for Disease Control’s (CDC) Health Studies Branch. The primary goal of the project was to develop and organize data, information, and knowledge about the current regulatory status, conditions, and use of unregulated water sources on Tribal lands across the USA. The data collected can be used to describe use of unregulated drinking water sources in order to identify regions that may be at higher risk for exposure to contaminants. It can also be useful to identify water-related issues of greatest concern to Tribes. The results of the project could provide information to guide potential future monitoring or funding opportunities (National Tribal Water Center 2017).

24.5  General Considerations to Address Water Issues Medical geologists work collaboratively with other scientists and with populations that are facing health issues related to geological factors and place. An understanding of the social structures, social definitions, and social determinants of health in IPNA populations is important to be able to be a part of the decisions that ultimately may lead to better health outcomes in these communities. Communities define health differently. This is cultural competence. Indigenous peoples look at health through a connectedness lens in a more holistic view than most western scientists. Water is a vital part of this connectedness. The World Health Organization defines health as, “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (World Health Organization 1946) that is “a positive concept emphasizing social and personal resources as well as physical capabilities” (World Health Organization 1998). IPNA peoples define health and well-being similarly, including extended familial and community-wide considerations, reflecting interlinked social, cultural, spiritual, environmental, and psychological aspects of health (Donatuto et al. 2014). Such Indigenous health systems are complex, structured in content and internal logic, and comprise practices and knowledge about connections between human beings, nature, and spiritual beings (Donatuto et  al. 2014). How health is defined and assessed is a high priority for Indigenous communities, who are confronted with considerable health risks from impacts to homelands and beyond (Donatuto et al. 2016).

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24.5.1  Health Assessments and Community-Driven Research The role, use, and methods used to conduct various types of human health risk assessments in evaluating environmental impact of proposed development of resources or cleanup of existing contamination that may be affecting INAP need to be considered. These types of assessments do not always reflect the uniqueness of Indigenous peoples. “At a minimum, a defensible and inclusive health assessment needs to reflect an understanding of the key values and priorities of the people in question and a mechanism for communicating these values to external decisions makers (e.g., regulator, industry, elected officials). In order to operationalize such a health assessment framework, the assessment must be driven and refined by the people in question for use in their own communities, reflecting their own unique histories and place-based uses of resources” (Donatuto et al. 2016). To be able to carry out these assessments or propose a medical geological study community-­ driven research should be developed with many partners. Standard medical or scientific studies based on western scientific methodology include systematic observation, measurement, and experiment followed by formulation, testing, and modification of hypotheses. To work effectively with Indigenous peoples these methods need to be modified. The key is working “with” communities. Many IPNA have been researched by western scientists without reporting back any of the results to the people. This has led to wide distrust of researchers among IPNA. Some research may not even really be valid when conducted without community involvement. Gatekeeping, withholding information, has likely been practiced by some IPNA to protect those values that are not being reported in a culturally scientific valid method. Community-based participatory research (CBPR), community-­based monitoring (CBM), and in some studies a Tribal Participatory Research (TPR) framework coupled with CPBR studies are some ways that medical geologists and other scientists can work more effectively with IPNA. These methodologies are driven by the communities and require time to develop the collaboration and inclusion of community members and the social construction of knowledge specific to each tribal group. Foundations of the approaches and specific mechanisms that can be employed in collaborations between researchers and individual communities need to be researched specific to each unique group. Community advisory boards and or tribal steering committees are often included or should be considered to be included in any project. The time necessary to develop relationships and collaborations between tribes, communities, and researchers may affect timelines for projects and need to be adjusted accordingly. Involving the community in the design of research is a part of the CBPR process. There is no standardization in assessing the quality of research methods, effectiveness of interventions, or reporting requirements for this (Faridi et  al. 2007). Community-driven work has been recognized as appropriate and is often in some of the language included in government calls for research funding proposals when working with Indigenous Peoples. Health studies involving IPNA carried out in regular scientific method often do not have a large enough population to have a statistical significance (Van Dyke et al.

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2016). National public health reports typically aggregate data on all AI/AN to establish sample sizes large enough for robust findings. However, incidence and mortality rates for many health conditions in IPNA communities vary significantly by region (Van Dyke et al. 2016). When data from different geographic and cultural areas are aggregated or stratified without an informed assessment of their comparability, tribal differences may be obscured (Van Dyke et al. 2016). This is something that needs to be considered and working with biostatisticians and epidemiologists familiar with Indigenous health and culture would be extremely beneficial to any study design.

24.5.2  T  ribal Colleges, University Involvement, and Other Organizations Programs set up and established by organizations and universities that are sensitive to cultural practices have been utilized by some tribal groups. In Alaska, the Alaska Community Action on Toxics (ACAT) has been training people in communities that come to them and want the training since 2008 (Alaska Community Action on Toxics (ACAT) 2012). They have partnered with the University of Alaska Fairbanks Northwest Campus to offer annual college-credited field courses on environmental health and field sampling methods. These classes help to train village leaders to conduct their own community-based environmental health research. The community-­ based environmental health research field sampling institute brings together tribal leaders and other community members from more than a dozen Norton Sound villages for a week-long intensive training program which is held annually at either Nome or Anchorage (ACAT 2012). Participants gain hands-on experience with classroom and field sessions from environmental health experts. They learn about water quality testing, fish sampling, sediment coring, GIS computer mapping, and how to monitor stream health (ACAT 2012). Instructors teach participants how to use research tools such as semi-permeable membrane devices to detect pesticides and other industrial chemicals in water. Participants learn ways to determine the presence of endocrine-disrupting chemicals in fish (Van Dyke et al. 2016). The new skill is especially relevant because many Alaska Natives still rely on subsistence fishing, hunting, and gathering. Through hands-on investigations, participants explore streams, wetlands, and coastal areas. Participants learn how environmental contaminants may affect human health in the classroom and how to implement independent community-based environmental sampling programs in their villages. Alaska Community Action on Toxics collaborates with communities to conduct environmental sampling and training to better understand contamination associated with such areas as formerly used defense sites (FUDS), active and abandoned mining sites, and nuclear (radioactive) sites in remote areas of Alaska. ACAT has conducted sampling and analysis of contaminants including PCBs, pesticides, solvents, heavy metals, fuel- and oil-related compounds, and radioactive elements at the

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request of and in collaboration with communities to design and conduct sampling projects (Alaska Community Action on Toxics (ACAT) 2012). This program provides communities with independent analysis that will help inform their decisions and achieve environmental health and justice. The Rural Alaska Monitoring Program (RAMP) is an EPA grant-funded monitoring program, operated by Alaska Native Tribal Health Consortium in partnership with Kawerak, Inc. and the communities of the Bering Strait region (ANTHC 2019a). RAMP provides training to residents who wish to participate in testing their subsistence-harvested marine and land mammals and traditional water sources for wildlife infections that might be a risk (ANTHC 2019b). The Alaska Pacific University (APU) in Anchorage Alaska is working to become a tribal university. The university collaborates with communities and Tribal partners. APU offers an Environmental Public Health (EPH) degree which prepares students to examine environmental hazards in the built and natural environment looking at tough issues such as climate change. The program is uniquely structured to combine distance, campus-based, and independent learning opportunities. Coursework is campus-based in Anchorage with options of both daytime and evening courses. After successful completion of initial EPH coursework, students are involved in 2–3 semesters of off-campus practicum serving the needs of rural or urban Alaskan communities (Alaska Pacific University 2019). In the summer of 2019, ANTHC and APU hosted the first Alaska Indigenous Research Program titled Promoting Resilience, Health and Wellness. The program included 3  weeks of courses which covered Indigenous and Western research methodologies, community-­ based participatory research, culturally responsive community engagement and communication, health research ethics, health research, and historical trauma. The goal of the program was to increase the health research capacity of AI/AN individuals and communities by providing cross-cultural research education (ANTHC 2019b). This is something that is needed because historically, AI/AN individuals have been underrepresented among researchers and health scientists, and there is a need for Western-trained researchers to be culturally grounded, respectful, and responsive in meeting the health needs of AI/AN communities. The program was open to anyone from experienced researchers and health professionals to people with little or no experience who are interested in health research and will be offered again.

24.5.3  C  ommunity-Based Education Local and Regional Examples In many Indigenous cultures learning is passed on by oral tradition and from elders, a community-based project of educating the youth that has been practiced for centuries. The Apsáalooke (Crow) reservation is the largest reservation in Montana. It is in rural south-central Montana and covers 2.3 million acres of the original tribal

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homelands. An estimated 7900 of the 11,000 enrolled Crow tribal members live on the reservation (Simonds et  al. 2018). The Bighorn and Little Bighorn rivers are important to the Apsáalooke people. Several CBPR studies over about 15  years’ time have identified water quality issues on the reservation including unsafe levels of chemical and microbial contaminants in over half of home wells on the reservation (McOliver et  al. 2015; Eggers et  al. 2015). Based on some of these studies, community members of the Apsáalooke Nation identified the lack of water-related environmental knowledge among children as an area of concern (Simonds et  al. 2018). The Guardians of the Living Water (GLW) project was developed. The GLW project was a local program designed to increase environmental health literacy among children and their families on the Crow reservation using the child-as-agent-­ of-change model (Simonds et al. 2018). The program involved work with community and academic partners which included members of the Crow Environmental Health Steering Committee, the Crow Agency Public School, Little Big Horn College, and Montana State University (Simonds et  al. 2018). The program was facilitated in a camp at the Crow Agency Public School for fifth- and sixth-grade children. The children learned about the science of water, learned about the importance of water to Crow culture from community members, and engaged in activities designed to support them in sharing what they learned (Simonds et  al. 2018). Children reported back what they learned to parents, grandparents, and peers, and in doing, this disseminated valuable information in the community. In subsequent camps, educational brochures with more specific information about water contamination and mitigation strategies to facilitate child-parent communication were implemented (Simonds et al. 2018). This success of the program stemmed from the trust initially built between partners which expanded throughout the community and benefited by integrating Apsáalooke values (Simonds et  al. 2018). Community-­ based education projects can be positive outcomes of ongoing CBPR projects as this project illustrates. An example of a regional educational program related to water with community participation is the Indigenous Observation Network (ION). The ION is a community-­based monitoring system for the Yukon River watershed which is a transborder watershed extending from Alaska to Canada (Yukon River Inter-Tribal Watershed Council 2018). The Indigenous People of the Yukon River Basin traditionally passed information down through oral tradition from land-based or water-­ based experience. The ION was established by the Yukon River Inter-Tribal Watershed Council (YRITWC) which facilitates the integration of these stories and experiences with scientific environmental monitoring (Yukon River Inter-Tribal Watershed Council 2018; Herman-Mercer et al. 2018). The YRITWC, and Yukon River Basin communities have partnered with the US Geological Survey to collect high-quality environmental data about the water and the land since 2006 (Yukon River Inter-Tribal Watershed Council 2018). Interactive maps (Fig. 24.8) were created by YRITWC using the available information from both the USA and Canada to provide an overview of potential threats to water in the Yukon River Watershed (Yukon River Inter-Tribal Watershed Council 2018).

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Fig. 24.8  The Yukon River Basin in Alaska and Canada showing all ION sample locations from 2006–2014 (Herman-Mercer et al: Data Quality from a Community-Based, Water-Quality Monitoring Project in the Yukon River Basin)

Data sources include the US and Canadian Governments, as well as the State of Alaska, and Yukon Territory agencies. With the map, individuals can view threats within the entire Yukon River Watershed in addition to viewing local threats by zooming into their home community (Yukon River Inter-Tribal Watershed Council 2018; Herman-Mercer et al. 2018). The accuracy, precision, and reliability of data collected by non-professionals in citizen science or community-based science are sometimes questioned in the western scientific community. The ION data were examined in the context of a standard data life cycle: plan, collect, assure, and describe, as compared to professional scientific activities and found to be of high quality (Herman-Mercer et  al. 2018). With consistent protocols and participant training, CBM projects can collect data that are accurate, precise, and reliable (Herman-Mercer et al. 2018). The Local Environmental Observer (LEO) Network is another type of environmental community-driven monitoring program that was developed by the Alaska Native Tribal Health Consortium with primary funding provided by the US EPA and the Bureau of Ocean Energy Management (ANTHC 2019c). The program works by having people submit what they observe often as photos and locations with descriptions. Experts on specific topics “apply traditional knowledge, western science and

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technology to document significant, unusual or unprecedented environmental events in communities around Alaska and the world,” (ANTHC 2019c). The observations recorded range from changes in seasonality, plants and wildlife, and weather conditions to natural hazards including coastal erosion, flooding, droughts, wildfire, and other events that can threaten food security, water security, and community health (ANTHC 2019c). The LEO Network helps to increase understanding about environmental change so communities can adapt in healthy ways. Web-accessible interactive maps are used to display observations and share the observations with network members. The maps contain descriptions of observations, photos, expert consultations, and links to information resources (ANTHC 2019c). The LEO Network is available through a web application and as a mobile app “LEO Reporter” for iPhone and iPad and Android. Programs such as the three described help create awareness of water-related issues that Indigenous people are facing using community-based methods that use the cultural strengths of traditional knowledge paired with western science for environmental awareness of whole communities. These programs and research methods can only be achieved by taking time to establish the important communication between all partners involved. This chapter has given examples of a fraction of the issues related to water that affect Indigenous Peoples of North America. Indigenous peoples represent a very small percentage of people in North America though many have similar problems with issues related to water and health not only of individuals but whole cultures. The way this subject applies to practical applications of Medical Geology is in the future there could be a lot of opportunity for projects to be worked on with IPNA. Medical Geological studies in any population need to be done with cultural competence (both directions) from an individual, community, or Nation-to-Nation basis, whether working with Indigenous on non-Indigenous communities. One of the aspects of scientific studies carried out by Western Scientists that has been neglected in the past but is starting to be acknowledged is a lack of understanding of individual cultures including the place not just the people. Many cultures include water, land, and wildlife. To be respectful of these things requires communication with communities or peoples whose area includes these specific areas of study. Even to collect water, rock, or soil samples typical of geologic studies, should be done with these community inputs. There are not many Indigenous geologists and scientists in the world who can lead these studies though there are more Indigenous people becoming educated. Indigenous scientists need to be versed in both Western and Indigenous views to be able to work in both. The Indigenous population that lives off-reserve or off-reservation would add another dimension to this topic. Many of these people are still connected to family and understand the water/land/family connection. A global perspective of these issues would be similar when issues related to colonization and reconciliation for water and land have affected different people in each country. Scientists especially in medical-related studies, working in other countries need to be able to communicate with people and know the customs as well as including contributions from different scientific fields if the problems are to be understood, mitigated, or resolved.

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Chapter 25

Veterinary Geology Jan Myburgh, Kelly McGowan, and Anthony Davis

Abstract  Guided by knowledge of the geology of an area and the effect that this inevitably has on soil mineral composition, a livestock veterinarian using this knowledge gains an essential advantage in identifying potential imbalances in his patients. This is especially true of animals, which generally tend to be “prisoners of space”, fully reliant on the grazing available to them. The mineral content of plants (e.g. grass) is influenced by the soil composition. Hence, the inextricable link between soil geochemistry and animal health, which justifies the emergence of the discipline termed “Veterinary Geology”. The complexity of the mineral journey from bedrock to animal tissues requires the co-operation of geologists, soil scientists, agronomists, nutritionists, biochemists and veterinarians to shed light on how these various interactions affect animal health, and as consumers of animal products, human health as well. Minerals have a significant impact on the health, immune function and production potential of livestock. The discipline of Veterinary Geology provides a useful tool to ensure that imbalances are recognised and adjusted correctly. Keywords  Geology · Soil · Plants · Water · Minerals · Deficiency · Toxicity · Animal health · Veterinary public health · One health

25.1  Introduction Veterinary Geology is a discipline which aims to predict potential mineral imbalances in animals by studying the geological composition of a specific area. The geological composition of bedrock has a fundamental impact on the soil composition, J. Myburgh (*) Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng Province, South Africa e-mail: [email protected] K. McGowan Hill’s Pet Nutrition, Green Cove Springs, FL, USA A. Davis Humansdorp Veterinary Clinic, Humansdorp, Eastern Cape Province, South Africa e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_25

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and this in turn has an impact on the composition of vegetation available to animals for grazing. Understanding the potential impact that the geological composition could have on soil mineral content (geochemistry) alerts the veterinarian to potential clinical manifestations of mineral imbalances. This is of immense diagnostic value, since most mineral deficiencies manifest subtly and can be easily overlooked. The impact of mineral deficiencies or toxicities on human health established Medical Geology as an accepted international discipline. We propose that the geological composition of an area potentially has an even greater impact on animal health, since animals are generally confined to this environment without having the benefit of deriving nutrition from other sources. In general, unsupplemented farm animals and wildlife are more dependent on their environment for minerals and other nutrients than humans. Camp and farm fences invariably restrict the free movement of farm animals. Similarly, free movement (or migration over long distances) of wildlife is impeded by man-made game park boundaries (Van Ryssen 2001). Veterinary Geology focuses on the interactions between animals, their geological environment and the health effects caused by specific geological areas of unexpected composition (geological anomalies) (Bowman et al. 2003; Dissanayake and Chandrajith 2009; Jones 2005; Webb 1964). It is a false assumption to make that minerals are homogeneously distributed (Brunetti 2014; Davies and Mundalamo 2010; Maskall and Thornton 1996; Whitehead 2000). Soil mineral composition (geochemistry) differs widely, likewise plants utilised as forage sources will also differ in mineral concentrations (Brunetti 2014; Thornton 2002; Whitehead 2000). Some plants may accumulate minerals, so that plant concentrations differ from the soil’s mineral content, but generally if a specific mineral is deficient in the soil, it will most likely also be deficient in the plant (Van Ryssen 2001; Whitehead 2000). Any mineral imbalance in a specific area (e.g. high lead concentrations or low selenium in the soil), where animals are kept, may affect their health and well-being (Davies 2008; Dissanayake and Chandrajith 2007; Maskall and Thornton 1996). The negative health impacts will be additive if their drinking water (groundwater or surface water sources) is also impacted by the same geological anomaly (Edmunds and Smedley 1996). Humans, as consumers of animal products (milk, meat, eggs, etc.), are indirectly affected if geological anomalies or mineral imbalances affect production animals (Schwabe 1984). Veterinary Geology may be defined as: “the influence of the geological environment on livestock and wildlife health, wellbeing, production and reproduction”. Animals are usually affected through the intake of heavy metals, trace elements and other toxic substances present in plant material, soil (geophagia) and drinking water from their immediate environment. Livestock farming has been practised for millennia (Bellwood 2005). More recently, intensive farming with livestock and wildlife, on smaller farms or in specific camps, has increased in popularity. Unfortunately, fences or other man-made borders can confine these animals in specific areas that may be associated with specific geological anomalies. Geology, chemical soil composition or geochemistry of these specific areas becomes very important as it may influence the health and productivity of confined animals through mineral intoxications or deficiencies (Bath 1979; Edmunds and Smedley 1996; Maskall and Thornton 1996; Mills 1996; Neser et al. 1997).

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Local geochemistry can play an important pre-disposing role in causing mineral imbalances, especially deficiencies, which may affect the health, production and reproduction (fertility) of animals in a negative way (Courtman et al. 2012; Edmunds and Smedley 1996; Flueck et  al. 2012; Kincaid 2000; Mills 1996; Van Ryssen 2001). Similarly, excessive concentrations of specific elements from the environment (soil, plants or drinking water), may also influence animals, either directly (toxicity) or indirectly due to secondary imbalances of other specific trace elements (Bath 1979; Edmunds and Smedley 1996; Neser et al. 1997). An important example of an element that may cause secondary deficiencies is sulphur. Sulphur per se is not a very toxic element, but high intakes can cause selenium and copper deficiencies thereby affecting the well-being of the animals, and in some cases may even contribute to mortality (Flueck et al. 2012; Kincaid 2000). Many minerals, even though required in trace quantities (sometimes called trace elements) by animals, play significant roles in enzyme functionality and immune system capacity (Birringer et al. 2002; Flueck et al. 2012; Kincaid 2000). However, if an imbalance compromises the immune system, infectious microorganisms that normally would not affect immunocompetent animals may seriously affect their health and even lead to the death of the animal. Humans are potentially exposed to the same geological anomalies (especially in rural areas) as animals and mineral imbalances may also affect human health (Davies 2008; Dissanayake and Chandrajith 2007; Fordyce 2005; Plant et al. 1996; Schwabe 1984). Animals, especially livestock, are generally more “geologically entrapped” than humans. Therefore, an understanding of the geology of a specific area, coupled to recognition of clinical signs in geologically entrapped animals, may sound the alarm that human health may also be at risk, hence the powerful One Health implications of this fascinating new discipline (see Sect. 25.5.2 below).

25.2  Animals as Sentinels of the Geological Environment Farm animals and some wildlife are inherently better “sentinels” of their geological environment than humans, because they are most often completely reliant on the nutritional elements that they derive from the plants grown in the soil of the restricted area in which they live (Picture 25.1). The same can be said of humans living in very remote villages (“small village syndrome” or that they are “geologically entrapped” or“prisoners of space”), where there is little access to alternatives, other than the food grown in the immediate vicinity of their habitations. Whereas livestock and some wildlife are trapped and very dependent on their environment for all their nutritional needs, humans are mostly “free roaming”, except for young children and elderly people that often do not move away from their rural villages. Even if humans are unable to move around, their food is often transported over long distances and obtained from various unrelated sources (some as far away as another country). Currently, long-distance migration of wildlife is restricted by man-made fences and borders. However, a possible driver for migration of animals could be to satisfy

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Picture 25.1  Animals are completely reliant on the nutritional elements that they derive from the plants grown in the soil of the restricted area in which they live. If trapped on a geological anomaly it may influence their health. (Picture: Colin Langton)

specific nutritional needs (forage nutrients and mineral concentrations) (Ben-Shahar and Coe 1992; McNaughton 1988, 1990). McNaughton (1990) speculated that seasonal movement of migratory grazers in the Serengeti ecosystem is stimulated by different mineral concentrations of grass growing in specific geochemical areas. Kreulen (1975) suggested that habitat selection of wildebeest (Connochaetes taurinus) on the Serengeti plains might be due to regional differences in calcium concentrations of grazing. In case of a geological anomaly, the health of animals “trapped” in a specific area will be affected, especially if no supplementary feeding is given. Extensively farmed livestock not given any supplementary minerals in the form of licks, or people who have no access to alternative food sources, would be an accurate reflectors of the mineral geology of a specific area (Van Ryssen 2001).

25.3  Anthropogenic Disturbances of the Geological Environment Mining activity is usually undertaken in specific areas where valuable minerals or geological materials occur in abnormally high concentrations (Davies 2008; Gummow

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et al. 1991). Soil in the same vicinity will most probably also contain high concentrations of the sought-after minerals, increasing the health risk to humans and animals living permanently in that specific geological environment (Davies and Mundalamo 2010; Gummow et al. 1991). In addition to this, abnormally high levels of mineralrich ore, brought to the surface, may result in an increase in mineral-rich dust being scattered onto soil and plant surfaces, downwind to the mine dumps or being released into the atmosphere during processing (Gummow et  al. 1991). Certain mined elements, such as sulphur, iron and vanadium are examples of contaminants that may influence the geochemistry of the surrounding area (Davies and Mundalamo 2010). This would then potentially pre-dispose to mineral imbalances in animals utilising this affected environment for grazing and, in addition, may have a serious economic impact if the health of these animals is affected (Gummow et al. 1991). Coal burning for power generation releases sulphur (from pyrite, FeS2) into the atmosphere. Sulphuric acid (acid rain) is formed when the sulphur contacts water vapour and oxygen. Acid rain has two major effects—the one is to reduce the pH of the soil, which has a major effect on the availability of several trace elements. The other effect is that the sulphur molecules tend to influence other trace elements in the soil, potentially rendering them unavailable for absorption by plants. Courtman et al. (2012) investigated the bioavailability of selenium to maize/corn crops in areas influenced by acid rain. Despite an apparently acceptable concentration of selenium in the soil, 94% of the maize/corn samples were deficient in selenium. The proposed reasons for the deficiencies in maize/corn are soil acidification and an increase in sulphur concentration (Courtman et al. 2012). Soil microorganisms (especially mycorrhizal fungi) are not often considered to be important role-players contributing to the concentrations of micronutrients in plants (Brown 2018; Montgomery 2017). However, Montgomery (2017) stated that soil microorganisms play an important role to unlock bound-up nutrients, like phosphorus and other minerals, for uptake by plants. The delicate interaction between plant roots and soil microorganisms has only been thoroughly investigated during the last decade. Soil bacteria and mycorrhizal fungi work together to source micronutrients from the soil for the plants. The micronutrients are transported over long distances to the plant roots by the fungal hyphae in exchange for carbon rich exudates (sugars) (Montgomery 2017). Any farmer or landowner will benefit significantly if the underground microorganism network is protected and healthy (Brown 2018; Montgomery 2017; Tickell 2017). Anthropogenic disturbances and degradation of soil health have a more significant impact in the case of annual cash crops, where seasonal ploughing, tillage and soil disturbances destroy the beneficial microorganism networks in the soil (Brown 2018; Montgomery 2007, 2017). No-tillage is a better option to minimise the disturbance of the soil mycorrhiza and other microorganisms, and to improve the general soil health (Brown 2018; Montgomery 2007, 2017). Unfortunately, severe overgrazing, mismanagement of grasslands (e.g. unnecessary and excessive annual burning) and the change of soil chemistry through pollution (e.g. acid rain) will have a similar detrimental effect on soil microorganism composition and health, and therefore, may also indirectly influence the concentration of micronutrients available for uptake by different plant species.

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Lowdermilk (1953) reported that general mismanagement of pastures and the degradation of soil have contributed to the demise of villages, communities or even entire civilizations in the past. However, careful stewardship of the earth’s resources, through optimal crop management and soil conservation, has enabled other societies to flourish for centuries (Montgomery 2007; Lowdermilk 1953; Tickell 2017). The link between soil fertility and animal health has already been addressed by William Albrecht more than six decades ago (first published in 1958) (Albrecht 2005). More in-depth follow-up research is urgently needed, in future, to focus specifically on the interactions between soil, plants and animals.

25.4  Impact of Geology on Animal Health Livestock and wildlife depend on soil as the most important source of minerals for their daily physiological needs and, therefore, also their health (Albrecht 2005; Jones 2005; Mills 1996; Whitehead 2000). Plant material (grass, weeds, shrubs and trees) is the most direct source of minerals for herbivores, although other sources, like drinking water and soil (geophagia), may also contribute to their daily intake of minerals (Mills 1996; Whitehead 2000). However, supplementary feeding and licks are used in some areas as an additional sources of minerals for animals (Kincaid 2000; Trotter 2005).

25.4.1  Soil, Plant and Animal Interactions For herbivores to obtain minerals in sufficient concentrations, the specific element must be present in optimal quantities in plant material. Unfortunately, the movement of minerals from bedrock geology to soil to plant to animal is not a straightforward process (Whitehead 2000). In addition, the physiological interactions within the body of the animal are also very complex and dynamic. The interphases between: soil and plant; plant and animal; gastrointestinal tract and systemic circulation; systemic circulation and intracellular microenvironment; significantly influence the eventual intracellular concentration and the biochemical impact in the animal (Kincaid 2000; Whitehead 2000). In contrast to the very stable and predictable bedrock mineral concentrations, the surface soil layer is more dynamic and susceptible to short-term changes and external influences (Montgomery 2007, 2017). The soil layer to which the plant roots are exposed is, therefore, very important from a livestock and wildlife nutritional viewpoint (Montgomery 2017; Whitehead 2000). However, specific elements that may be abundant in soil are not necessarily present in plant material from that area. Factors that may influence the uptake of minerals by the plants are: soil concentration of the element; soil pH; soil type; speciation of the element; and the concentration of antagonists (Plant et al. 1996).

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An additional complicating factor is that some plants may accumulate minerals, so plant mineral content is not always an accurate reflection of soil mineral content. Selenium is not required by plants. High plant selenium concentrations may become a toxicological risk for animals consuming the plant material. Several plant species have developed mechanisms to accumulate selenium. This has been demonstrated in several plant families, including Asteraceae, Brassicaceae, Fabaceae and Lecythidaceae (White 2016). The intake of high concentrations of selenium by animals and humans may cause toxicity (Koller and Exon 1986). However, the clinical problems caused by a low selenium intake is more well-known (see Sect. 25.5.1). “Blind Staggers”, occurring in the western parts of the United States of America, was believed to be caused by the high intake of selenium (O’Toole et  al. 1996). However, the intake of forages (high sulphur concentrations) and/or drinking water (high sulphate concentrations) is now considered to be the cause of this toxicosis. The excess intake of sulphur leads to the development of polioencephalomalacia and the characteristic clinical signs of blind staggers (O’Toole et al. 1996). Once ingested by an animal, the element’s journey becomes no less complicated. As is the case at the soil–plant interphase, antagonists or blockers (e.g. sulphur) may also influence mineral availability within the animal. Despite the existence of complex biochemical pathways to process minerals, catering for minor excesses and deficiencies, these systems, just as in plants, have a limit to their ability to compensate. Minerals are processed differently when ingested by a monogastric animal as opposed to a ruminant. A monogastric animal has a far simpler digestive system and minerals enter the circulation relatively easily after ingestion (Spears 2003). This is clearly demonstrated by the poor absorption of supplemented inorganic minerals in ruminants. A ruminant has a fermentation tank that minerals must deal with first. Since rumen protozoa and bacteria also have a trace mineral requirement, much of the supplemented minerals are utilised by these organisms, so inorganic minerals are less available for absorption by the ruminant. Organic minerals chelated to an amino acid will more easily bypass the rumen and are then absorbed in the gut. Even though minerals are required in very low quantities, most of them play essential roles in important enzyme systems. As an example, selenium is an essential component of glutathione peroxidase, one of two major enzymes in the anti-­ oxidant pathway (Birringer et  al. 2002). This pathway protects mammalian cells from oxidative damage due to free oxygen radicals, toxic breakdown products of breathed oxygen, so this enzyme is continuously required and its absence, or a deficiency, will result in a less than adequate anti-oxidant system, which will pre-­ dispose any animal to chemical damage and compromised immune function. Copper is an essential component of superoxide dismutase, the other major anti-oxidant enzymes, so a deficit here will also have similar consequences (Kincaid 2000). Any deviation in the mineral content of specific plants species, that animals pre-­ dominantly consume in a specific area, could easily lead to either toxic levels or a deficiency. Complicated by this is the fact that different animal species biochemically manage minerals in different ways (Birringer et al. 2002; Kincaid 2000; Spears 2003). For example, sheep are, in general, more intolerant of copper and will develop symptoms of copper intoxication much easier, while cattle on the same grazing will be unaffected (Bath 1979; Kincaid 2000).

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“Enzootic icterus” is the name used for the clinical disease (usually fatal) in sheep after the chronic accumulation of copper in their livers (Bath 1979). This disease only occurs in a specific geological area (Karoo dolerite) in South Africa associated with higher than normal concentrations of copper in the soil and specific plants (e.g. Karoo bushes). Any form of acute stress (e.g. road transport) causes the sudden release of copper from the liver. The high copper levels in the systemic circulation eventually cause acute death of the affected sheep (Bath 1979). Conversely, an example of how a low concentration of an element in the soil affects the health of livestock, is cobalt which is deficient in some parts of the United Kingdom. Lark et al. (2014) mapped the geochemical concentrations of cobalt in Ireland. The soil maps of low cobalt concentrations can be used to predict or explain the low concentrations in the animals from those areas (Jones 2005; Lark et  al. 2014). In general, if a geochemical deficiency is detected in a specific area, corresponding low concentrations are most likely also a problem in the livestock from that specific area or district. An on-farm investigation was done by Davis and Myburgh (2016) to investigate the sudden onset of beef calves being born either weak or dead (stillborn). Necropsies were performed on the dead calves to determine the aetiology. A consistent finding was that the muscles of the calves were pale, reminiscent of chicken meat. Liver and blood samples were submitted for selenium testing and a deficiency was confirmed. Cattle from this herd, as well as animals from neighbouring farms were diagnosed to be selenium deficient. Immediate measures were taken to supplement cattle parenterally and a lick was formulated using an organic selenium source. After initiating supplementation of calves and dry cows, no further stillbirths nor weak calves were reported. Weight gain improved and after months of supplementation, there was an improvement in weaning mass and conception rate (Anthony Davis, unpublished data). The deficiency could be diagnosed using animal tissue and blood samples, but it usually does not confirm what the cause of this deficiency was.

25.4.2  Confirmation of Health Impact The clinical presentation of mineral imbalances is often very vague. Mineral imbalances are often underdiagnosed by veterinarians, either due to the sub-clinical nature of the problem (livestock not showing obvious clinical signs indicating a mineral imbalance) or the clinician does not consider it to be an important differential diagnosis. Infectious and metabolic diseases are more often considered to be important causes of animal health problems. Monitoring mineral status of animals requires specialist laboratory support. Testing of animal tissues (liver biopsy samples for trace mineral analysis: copper, cobalt, chromium, iron, manganese, selenium, zinc), blood (for copper and selenium concentrations) are useful. Adjunctive testing of drinking water, soil and plant material provide supportive evidence for the presence of a deficiency. The final measure of an imbalance, but the first presentation to the veterinarian, will be the clinical symptoms commensurate with the specific mineral deficiency or

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excess seen. For this reason, Kincaid (2000) made the astute observation that ultimately the only reliable way to assess the impact of an imbalance is to assess the clinical response in animals after the correction of the deficiency or prevention of toxicosis.

25.5  V  eterinary Public Health and the Geological Environment Veterinary Public Health (VPH) is an acknowledged global discipline and may be defined as a component of Public or Human Health that focuses on the application of Veterinary Science to manage the risk of human exposure to animal products containing harmful agents or chemicals. Schwabe (1984) already started promoting the idea, more than five decades ago, that the health of humans and animals is closely linked to each other. He named it “One Medicine” (Schwabe 1984). However, he ignored the potential role of the geological environment in affecting human and animal health. Medical Geology (not a new concept, only a relatively new discipline) effectively turned around the situation by emphasizing the important role of the geological environment, which may promote human well-being (e.g. optimal nutrition), but may also negatively affect human health (e.g. toxicity or deficiency) in some cases. There are inextricable links between environmental health, animal health and human health. Infectious diseases are, as a rule, more species-specific, whereas chemicals, especially toxic doses of minerals, affect a wide range of species in a very similar way. Toxicological problems are, generally, under-recognised or under-­ diagnosed as serious role-players affecting the health of ecosystems, animals and humans. Potentially harmful environmental elements affect humans and animals in a very similar way (e.g. lead poisoning). Fluorosis (high levels of fluorine in drinking water) also has similar negative health consequences in humans and animals (Edmunds and Smedley 1996). This situation becomes critical if potentially harmful chemicals are found in animal products that are intended for human consumption. If an impact on animal health is diagnosed in a specific area, there will most likely also be an impact on human health.

25.5.1  Soil, Plant, Animal and Human Interactions Charles Kellogg stated more than 80 years ago that: “Essentially, all life depends upon the soil. There can be no life without soil and no soil without life; they have evolved together” (Massy 2017). Humans and animals are dependent on their geological environment (drinking water, soil, plant material and animal products) to support or improve their well-being and health (Plant et  al. 1996; Webb 1964; Whitehead 2000). Tickell (2017) stated that: “every single thing you put in your mouth (that is food) needs soil”.

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Where plants are the connection between soil (geochemistry) and animals, animal products (e.g. milk, meat, eggs, etc.) are the link between animals and humans. Animal products are very important to support the daily nutritional needs of humans, but may also negatively affect humans through the transfer of infectious agents (e.g. zoonotic diseases) and poisonous chemicals (e.g. lead in bovine milk) (Mills 1996; Schwabe 1984). If animals are exposed to a geological anomaly, potential health problems may be transferred to humans via animal products. Good examples are milk and meat that are usually produced by farm animals kept specifically for these purposes. Chemicals in animal products, in general, may come from: anthropogenic chemicals and environmental pollutants (e.g. pesticides, pharmaceutical products, etc.); or chemicals occurring naturally in the geological environment. For the purpose of this review the long list of man-made chemicals (e.g. agricultural pesticides, pharmaceuticals, industrial pollutants, etc.) will not be emphasised. From a Veterinary Geological perspective, the main concern is that chemicals from a geological anomaly or anomalies may be present in animal products. Remote or rural environments are potentially more at risk (and constitute ideal study sites), since both animals and humans are generally reliant on locally sourced food and water (Maskall and Thornton 1996; Van Ryssen 2001). The World Health Organization recognises a specific type of malnutrition (Type B) in humans, where mineral imbalances or deficiencies are the main focus. Malnutrition, in general, refers to deficiencies, excesses, or imbalances in a person’s intake of nutrients, while Type B malnutrition, specifically, refers to the adequate intake of calories and protein, accompanied by a suboptimal intake of micronutrients like minerals and vitamins. (https://www.who.int/news-­room/fact-­sheets/detail/malnutrition). Most people living in remote areas are either self-employed or form the labour force for farms, mines and other small rural businesses. Malnutrition due to a geological anomaly (deficiency of toxicity) may significantly affect their health, directly or indirectly, and this effect is exacerbated in immunocompromised people. The high rate of HIV/AIDS and tuberculosis (TB) in Africa makes this effect particularly relevant. An immune system already compromised by an immuno-suppressive disease will be compromised further by a deficiency in a trace element. Selenium, for example, is an essential component of anti-oxidant enzyme systems necessary for optimal immune system function (Birringer et al. 2002; Courtman et al. 2012). Geological anomalies are recognised as the cause of human and animal nutritional problems (more important in the case of rural communities). Wherever the perception is that the soil is affecting health, the focus is usually more on a specific element that is locally available in abnormally high concentrations (e.g. lead toxicity). However, deficiencies (e.g. selenium deficiency) must not be underestimated, seeing that it may also affect health negatively. Mills (1996) mentioned the following elements as environmental deficiency risks: copper; selenium; cobalt; and iodine, while fluorine, lead and selenium were named as potential causes of toxicity (Mills 1996). Deep rural communities very often consume only animal and plant products that are locally produced, grown or sourced, as well as drinking groundwater coming from the same geological formation. From a Veterinary Public Health perspective, only the two most important animal products, namely milk and meat, will be discussed, using lead (toxicity) and selenium (deficiency) as examples.

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Low soil, plant and animal product selenium concentrations may directly contribute to the health problems caused in humans by a selenium deficiency (Fordyce 2005; Flueck et al. 2012; Hira et al. 2003; Cobo-Angel et al. 2014; Tinggi 2003; Yao et al. 2011). In some parts of China and Russia, a deficiency of selenium in the soil (contributing to a chronic low intake by people from the affected areas) is an important contributing factor for the development of Keshan disease (cardiomyopathy) (Lei et al. 2011; Mills 1996) and Kashin-Beck disease (osteochondropathy) (Guo et al. 2014; Xie et al. 2018) in humans. Conversely, with high selenium concentrations in soil (and animal products), the risk for humans to develop clinical signs associated with the intake of high concentrations of selenium (selenosis), is a possibility (Bauer 1997; Fordyce 2005; Yao et al. 2011). Selenium concentrations in milk and meat are dependent on local selenium concentrations in soil, and can easily be increased by feeding animals more selenium or by increasing the concentration of selenium in soil (Fordyce 2005; Cobo-Angel et  al. 2014; Tinggi 2003). Unfortunately, subtle selenium deficiencies may be missed by the clinicians in their human patients, especially if selenium imbalance is not considered to be an important differential diagnosis. Similarly, if veterinarians do not actively screen animals and animal products for selenium concentrations, imbalances will be missed. Medhi and Dufrasne  (2016) stated that the selenium concentration in bovine milk can be used as an easy way to assess the selenium status of a dairy herd. Agricultural methods of food production used in industrialised and intensive production systems are also being blamed for food quality deterioration (nutrient depletion) (Miller 2016; Thomas 2003, 2007). Brown (2018) reported that nutrient depletion in cultivated plants already started when the first crop farmers began selecting for specific characteristics, and that modern agricultural practices expedited the nutrient quality deterioration. Unfortunately, in this case, city dwellers that are totally dependent on mass-produced food, are more significantly affected (Miller 2016; Thomas 2003). In contrast to deficiencies, the intake of specific elements in high concentrations may not only affect animals, but could also influence the quality of animal products (Picture 25.2). Lead is a potentially harmful element that may be excreted in milk (Bischoff et al. 2014). Lead is not needed in the body and is considered an element very detrimental to health, especially in unborn babies and young children (Bischoff et al. 2014; Thompson 2012). In general, sources of lead for dairy cattle may be: high lead in soil (galena, PbS); lead in groundwater; battery plates in feed; grass next to busy roads wherever lead-based fuel is still used (Thompson 2012; Checkley et al. 2002). The last two examples are man-made, while the first two examples are more closely associated with local geology. The intake of lead battery plates is the most important cause of lead poisoning in cattle (Bischoff et  al. 2014; Checkley et al. 2002). Lead is excreted in the milk of dairy cows (Bischoff et al. 2014). This may become a public health problem if humans, especially pregnant mothers and young children, consume cow’s milk containing lead residues (Thompson 2012). Lead in milk may easily go undetected if not specifically tested for by authorities (Bischoff et al. 2014).

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Picture 25.2  The intake of specific elements (e.g. lead) in high concentrations may not only affect the health of animals, but could also influence the quality of the products (e.g. milk) produced for human consumption. (Picture: Anthony Davis)

Similarly, lead may also accumulate in meat (Lukáčová et al. 2014). The skeletal system (bones) is the most important organ system in which lead accumulates (Thompson 2012). Excess wildlife (several species) on a lead mine’s property were harvested with the intention of donating the meat to the surrounding communities. Unfortunately, lead concentrations from all carcasses tested were found to be higher than the World Health Organization’s guidelines for concentrations in meat intended for human consumption (Jan Myburgh, unpublished data). All the carcasses were destroyed. Under specific circumstances both humans (Gomes 2018) and animals (Panichev et al. 2013; Stephenson et al. 2011) are known to eat soil or clay (geophagia), most probably to address a mineral deficiency or for specific therapeutic reasons. In addition, humans also use clays or earth products for skin care purposes (Gomes 2018). The specific soil (from a geological anomaly) that is consumed usually has specific chemical properties that the users believe to have positive health effects. However, if soil is consumed from a local geological anomaly (high concentrations of specific elements), it may affect the health of the soil consumers in a negative way.

25.5.2  One Health Concept Although the importance of soil, plant and animal interactions is well-known, it also strongly supports the One Health concept (Gyles 2016). The “One Health” idea is

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not new, Calvin Schwabe (DVM) is credited with having coined the term “One Medicine” nearly five decades ago. He advocated a closer collaboration between veterinarians and medical professionals (Gyles 2016; Schwabe 1984). The term “One Medicine” has largely been replaced by the term “One Health” (Pal et al. 2014). In the case of One Health, infectious diseases generally receive more attention, than environmental problems (Gyles 2016; Pal et al. 2014). Infectious diseases, as a rule, are more species-specific (e.g. viral infections), whereas chemicals, especially toxic doses of elements from the environment, affect a wide range of species in similar ways. A big concern is that chemicals in animal products are not easily detectable, unless specific and expensive laboratory tests are used. Therefore, chemical imbalances (toxicities and deficiencies) are under-diagnosed as causes of ecosystem, animal and human ill-health. If animal health problems exist, caused by geological anomalies, an impact on human health is possible.

25.6  Drinking Water Drinking water for animals, in general, comes from: surface water sources (lakes, dams, rivers, canals and springs) and groundwater e.g. boreholes or wells (DWAF 1996). It is widely accepted that human and animal health may be affected by the chemical composition of drinking water (DWAF 1996; Edmunds and Smedley 1996; Keller 1978) (Picture 25.3). However, drinking water may also be a valuable source of good-quality minerals (DWAF 1996; Edmunds and Smedley 1996). The concept of “geological entrapment” must also take into consideration, the water source(s) used by livestock and wildlife, where these animals may not be able to voluntarily use other water sources and are forced to only drink the water that is supplied. Drinking water, especially groundwater, may be an important source of potentially hazardous constituents (PHCs) coming from the surrounding geology (DWAF 1996). The risk of clinical disease developing in animals, caused by PHCs or mineral imbalances, may be reduced through water dilution, where animals have the choice to consume water from multiple sources (especially if the water is from unrelated aquifers). However, in small villages and deep rural areas the available water sources are often limited, forcing both humans and animals to drink the same water (often the only water available). In some developed countries, the human population may have different drinking water sources if compared to livestock. In Florida (USA), for example, more than 90% of the population relies on groundwater withdrawals for their drinking water (Marella 2004). Of that 90%, 60% of the groundwater withdrawals originate from the Floridan Aquifer, a carbonate (e.g. limestone) aquifer system that is overlain by an upper confining layer and a series of intermediate confined aquifers and surficial unconfined aquifers. Wells drilled into the Floridan Aquifer can extend, on average, from ±30 m (100 ft) downwards to ±150 m (500 feet) below land surface for many public supply wells. The cost associated with drilling to this depth can be prohibitive, and thus many private agricultural wells draw from shallower intermediate and surficial aquifers. Recent estimates suggest that more than 50% of agricultural water withdrawal in Florida is from surface waters (Marella 2004), such as Lake

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Picture 25.3  The quality of drinking water may influence animal health. The chemical composition of groundwater is intricately linked to the surrounding geology. (Picture: Anthony Davis)

Okeechobee and its associated canals, as opposed to deep groundwater aquifers. In situations like this, it is likely that there is significantly less monitoring of agricultural water quality if compared to human drinking water, and PHC concentrations or contamination may, therefore, go undetected until animal production and health parameters are significantly affected.

25.6.1  Drinking Water Quantity and Quality Farmers and managers are often more concerned about the volume of water available (quantity), than the quality. This is understandable, seeing that insufficient water intake in animals (e.g. dairy cows) may directly influence their dry matter intake and milk production. Dairy cows need, in addition to their daily physiological requirement, ±3 L of water per L of milk produced (DWAF 1996). The composition of surface water (quality), being more susceptible to anthropogenic contamination and chemical changes from integration of other water sources within a drainage basin, can fluctuate greatly over time, and can have different chemical profiles across relatively short distances (Brunke and Gonser 1997; Sophocleous 2002; Keery et al. 2007). For these reasons, and in the absence of regular water testing, livestock supplied with surface water, or water from unconfined aquifers, may be clinically affected if water of poor quality is consumed over longer periods.

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25.6.2  C  ontribution of Geology to the Composition of Groundwater Groundwater composition (quality) is more directly related to the bedrock geology, than surface water. Poor water quality, due to high concentrations of specific PHCs or mineral imbalances may influence animal health (DWAF 1996; Edmunds and Smedley 1996). Drinking water, specifically from a groundwater source in an area with a geological anomaly, in addition, may contribute to the total intake of specific harmful element(s) that animals get from local plants and soil (Edmunds and Smedley 1996; Kabata-Pendias and Pendias 2000). The chemistry of groundwater is closely dependent on the mineralogy of the associated underground geological formations (Edmunds and Smedley 1996). While the composition of groundwater is inextricably linked to the geology of a region, it is important to understand that groundwater composition can vary with the depth of the borehole, and that groundwater transport is a major mechanism of exposure to geological chemicals. Below the water table, which is the upper surface of the zone of saturation, all pore spaces within the soil and bedrock are generally filled with groundwater. This groundwater is part of the continuous and dynamic flow of the hydrologic cycle (Winter et  al. 1998). Within the zone of saturation, there may be more than one aquifer, separated by one or more impermeable confining layers (Winter et  al. 1998). The water  chemistry of these discrete aquifers is controlled by the composition of the surrounding rock layers, and the length of time that the water is in contact with these rocks. Numerous chemical reactions, including acid-base reactions, oxidation-reduction reactions and the dissolution of minerals, ultimately influence the chemical composition of the groundwater within an aquifer. Groundwater should be considered, on a large scale, to be a continuously flowing and dynamic system, with a water sample collected from a specific source (borehole or well), only confirming the local geochemical profile. Fluoride is a well-documented groundwater problem and its presence in toxic concentrations may come from the local geology (more important) or anthropogenic sources (Dissanayake and Chandrajith 2009; DWAF 1996). Fluorine-rich host rocks can contribute significantly to the final concentrations of fluoride in groundwater sources, through weathering processes and circulating groundwater (Edmunds and Smedley 1996). Fluorite (CaF2), fluorapatite (Ca5(PO4)3F) and certain members of the mica and hornblende groups which may contain fluorine in trace amounts, are common mineral sources of fluorine in bedrock, and can be found in sedimentary, igneous and metamorphic rock types. Weathering processes and percolation of rainwater through fluorine-rich rocks may increase the fluoride concentration in groundwater. Additionally, the use of phosphate fertilizers, which may be derived from fluorapatite-rich sedimentary phosphate beds, can also contribute to the fluoride concentration in water. While its use in public water supplies for dental health purposes is widely documented, excessive fluoride intake via drinking water may have serious health consequences in both animals and humans. Skeletal and dental pathological changes are the most obvious (Dissanayake and Chandrajith 2009; DWAF 1996; Edmunds and Smedley 1996).

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25.7  R  ole of Veterinary Geology in the Diagnosis of Mineral Imbalances If veterinary clinicians understand the geology of the area in which they practice, they will be alerted to the possibility of mineral imbalances and be aware of the potential impact this could have on livestock. Since symptoms are generally subtle and often related to poor productivity, veterinarians generally first consider infectious, toxic or metabolic causes and do not consider the possibility of a mineral imbalance unless they know that this could be present. A geochemical map, highlighting minerals of importance to human and animal health, would be a very useful tool to any rural practitioner. Clinicians rely heavily on the results of liver biopsies and blood concentrations to make decisions concerning the need for supplementation of minerals to livestock. However, when interpreting these results, the clinician must be aware that the results, at best, only provide an indication of a trend, rather than being an absolute indicator of the true mineral status of the animal. There are numerous interactions from where the mineral journey begins in the bedrock, all the way to how minerals are incorporated into the enzyme systems where they exert their effects. A single measurement to determine whether a mineral is deficient or in excess, is clearly subject to a multitude of variables. The movement of minerals is an inherently complex process, so measurements provide clues, but a diagnosis can only be reached if the entire mineral journey is examined and assessed. Knowledge of the bedrock geology which ultimately determines the soil composition is of cardinal value and fully justifies the active practicing of the newly emerging discipline of Veterinary Geology. Accurate geochemical mapping will be of great value to livestock owners, wildlife managers and veterinarians to predict potential deficiencies in specific areas. Most geochemical and geological maps currently produced are intended for use by the mining industry and are, therefore, less relevant to animal health. Regional maps of soil mineral concentrations (geochemistry) relevant to animal and human health, must become readily available tools to anyone working with production animals.

25.8  Conclusion Veterinary Geology brings many unrelated disciplines together. Inputs are required from: soil scientists; geologists; pasture specialists; botanists; agronomists; ecologists; analytical chemists; and veterinarians to truly make this discipline function optimally. Veterinary Geological studies examine the influences and effects of the geological environment on animals and will alert the veterinarian to the possibility that mineral imbalances may occur in specific areas. It therefore supports sustainable livestock farming and wildlife management as well as the production of safe and wholesome animal products for human consumption: One Health in action!

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References Albrecht WA (2005) Soil fertility and animal health. The Albrecht Papers, vol 2, 2nd edn. Acres USA, Austin Bath GF (1979) Enzootic icterus—a form of chronic copper poisoning. J S Afr Vet Assoc 50:3–14 Bauer F (1997) Selenium and soils in the western United States. Elect Green J 7:1–5 Bellwood PS (2005) The first farmers: origins of agricultural societies. Blackwell, Oxford Ben-Shahar R, Coe MJ (1992) The relationship between soil factors, grass nutrients and the foraging behaviour of wildebeest and zebra. Oecologia 90:422–428 Birringer M, Pilawa S, Flohé L (2002) Trends in selenium biochemistry. Nat Prod Rep 2002(19):693–718 Bischoff K, Higgins W, Thompson B, Ebel JG (2014) Lead excretion in milk of accidentally exposed dairy cows. Food Addit Contam Pt A 31:839–844 Bowman CA, Bobrowsky PT, Selinus O (2003) Medical geology: new relevance in the earth sciences. Episodes 26:125–132 Brown G (2018) Dirt to soil—one family’s journey into regenerative agriculture. Chelsea Green Publishing, London Brunetti J (2014) The farm as ecosystem. Acres USA, Austin Brunke M, Gonser T (1997) The ecological significance of exchange processes between rivers and groundwater. Freshw Biol 37:1–33 Checkley S, Waldner C, Blakley B (2002) Lead poisoning in cattle: implications for food safety. Large Anim Vet Rounds 2:1–6 Cobo-Angel C, Wichtel J, Ceballos-Márquez A (2014) Selenium in milk and human health. Anim Front 4:38–43 Courtman C, van Ryssen JBJ, Oelofse A (2012) Selenium concentration of maize in South Africa and possible factors influencing the concentration. S Afr J Anim Sci 42:454–458 Davies TC (2008) Environmental health impacts of east African rift volcanism. Environ Geochem Health 30:325–338 Davies TC, Mundalamo HR (2010) Environmental health impacts of dispersed mineralisation in South Africa. Aust J Earth Sci 58:652–666 Davis AJ, Myburgh JG (2016) Investigation of stillbirths, perinatal mortality and weakness in beef calves with low-selenium whole blood concentrations. J S Afr Vet Assoc 87(1):e1–e6. https:// doi.org/10.4102/jsava.v87i1.1336 Department of Water Affairs and Forestry (DWAF) (1996) South African water quality guidelines. In: Agricultural use: livestock watering, vol 5, 2nd edn. CSIR Environmental Services, Pretoria, South Africa Dissanayake CB, Chandrajith R (2007) Medical geology in tropical countries with special reference to Sri Lanka. Environ Geochem Health 29:155–162 Dissanayake CB, Chandrajith R (2009) Introduction to medical geology—focus on tropical environments. Springer-Verlag, Berlin Edmunds WM, Smedley PL (1996) Groundwater geochemistry and health: an overview. In: Appleton JD, Fuge R, McCall GJH (eds) Environmental geochemistry and health, vol 113. Geological Society Special Publication, London, pp 91–105 Flueck WT, Smith-Flueck JM, Mionczynski J, Mincher BJ (2012) The implications of selenium deficiency for wild herbivore conservation: a review. Eur J Wildl Res 58:761–780. https://doi. org/10.1007/s10344-­012-­0645-­z Fordyce F (2005) Selenium deficiency and toxicity in the environment. In: Selinus O, Alloway B, Centeno JA, Finkelman RB, Fuge R, Lindh U, Smedley P (eds) Essentials of medical geology. Elsevier, Amsterdam, pp 373–415 Gomes CSF (2018) Healing and edible clays: a review of basic concepts, benefits and risks. Environ Geochem Health 40:1739–1765 Gummow B, Botha CJ, Basson AT, Bastianello SS (1991) Copper poisoning in ruminants: air pollution as a possible cause. Onderstepoort J Vet Res 58:33–39

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Neser JA, de Vries MA, de Vries M, van der Merwe AJ, Loock AH, Smith HJC, van der Vyver FH, Elsenbroek JH, Delport R (1997) The possible role of manganese poisoning in enzootic geophagia and hepatitis of calves and lambs. J S Afr Vet Assoc 68:2–7 O’Toole D, Raisbeck M, Case JC, Whitson TD (1996) Selenium-induced “blind staggers” and the related myths. A commentary on the extent of historical livestock losses attributed to selenosis on western US rangelands. Vet Pathol 33:104–116 Pal M, Gebrezabiher W, Rahman M (2014) The roles of veterinary, medical and environmental professionals to achieve one health. J Adv Vet Anim Res 1:148–155 Panichev AM, Golokhvast KS, Gulkov AN, Chekryzhov IY (2013) Geophagy in animals and geology of kudurs (mineral licks): a review of Russian publications. Environ Geochem Health 35:133–152 Plant JA, Baldock JW, Smith B (1996) The role of geochemistry in environmental and epidemiological studies in developing countries: a review. In: Appleton JD, Fuge R, McCall GJH (eds) Environmental geochemistry and health, vol 113. Geological Society Special Publication, London, pp 7–22 Schwabe CW (1984) Veterinary medicine and human health, 3rd edn. Williams & Wilkins, Baltimore, MD Sophocleous M (2002) Interactions between groundwater and surface water: the state of the science. Hydrgeol J 10:52–67 Spears JW (2003) Trace mineral bioavailability in ruminants. J Nutr 133:1506S–1509S Stephenson JD, Mills A, Eksteen JJ, Milewski AV, Myburgh JG (2011) Geochemistry of mineral licks at Loskop dam nature reserve, Mpumalanga Province, South Africa. Environ Geochem Health 33:49–53 Thomas DE (2003) A study of the mineral depletion of foods available to us as a nation over the period 1940–1991. Nutr Health 17:85–115 Thomas DE (2007) The mineral depletion of foods available to us as a nation (1940-2002)—a review of the 6th edition of McCance and Widdowson. Nutr Health 19:21–55 Thompson LJ (2012) Lead. In: Gupta RC (ed) Veterinary toxicology, 2nd edn. Academic Press, Waltham, pp 522–526 Thornton I (2002) Geochemistry and the mineral nutrition of agricultural livestock and wildlife. Appl Geochem 17:1017–1028 Tickell J (2017) Kiss the ground—how the food you eat can reverse climate change, heal your body & ultimately save our world. Enliven Books/Atria, New York Tinggi U (2003) Essentiality and toxicity of selenium and its status in Australia: a review. Toxicol Lett 137:103–110 Trotter B (2005) Soil minerals—the key to farming wealth and your own health, 3rd edn. Zealand Publishing House, Tauranga Van Ryssen JBJ (2001) Geographical distribution of the selenium status of herbivores in South Africa. S Afr J Anim Sci 31:1–8 Webb JS (1964) Geochemistry and life. New Sci 23:504–507 White P (2016) Selenium accumulation by plants. Ann Bot 117:217–235 Whitehead DC (2000) Nutrient elements in grassland: soil-plant-animal relationships. CAB International, Wallingford Winter TC, Harvey JW, Franke OL, Alley WM (1998) Ground water and surface water: a single resource. United States Geological Survey, Circular 1139 Xie D, Liao Y, Yue J, Zhang C, Wang Y, Deng C, Chen L (2018) Effects of five types of selenium supplementation for treatment of Kashin-Beck disease in children: a systematic review and network meta-analysis. Br Med J Open 8:e017883. https://doi.org/10.1136/bmjopen-­2017-­017883 Yao Y, Pei F, Kang P (2011) Selenium, iodine, and the relation with Kashin-Beck disease. Nutrition 27:1095–1100

Part IV

Medical Geology in Policy and Education

Introduction Education in medical geology is of utmost importance. Since the start of medical geology, education, formal courses, and short courses have exploded, and several textbooks for researchers and students have been produced. Also several medical geology literature databases have been produced. These databases are presented in Chap. 26. The researchers are working in more than 100 countries publishing their research in hundreds of geographically and scientifically diverse journals. This diversity, though healthy, makes it difficult to keep up with current, relevant, research papers. A survey of several hundred articles in Google Scholar and PubMed using the keywords “geology and health” and “medical geology” published since 2006 revealed more than 300 articles in 166 different journal outlets. The articles appeared in journals directed to audiences in general science, geology/geochemistry, mineralogy/mining, soil science, hydrology, medical science/public health, nutrition, radiation/hazardous materials, occupational health, environmental science, agronomy, geography, chemistry, physics, and archeology. There are also chapters on medical geology issues in books. In addition, there are books on medical geology in languages other than English, for example, in Chinese, Portuguese, Farsi, Hindi, Spanish, and Swedish. Medical geology education in Africa is covered in Chap. 27. The African continent is characterized by a very complex and dynamic geological history and evolution including frequent earthquakes and volcanic eruptions in tectonically active regions. This is in addition to water toxicity due to interaction with the geological environment. Furthermore, the continent is known for its mining activities and petroleum exploration, which enhance the release of chemical elements and dust into the environment. Considering the possible health impacts of these natural geo-­ environmental and anthropogenic materials, factors and processes on humans and animals, it has become necessary and urgent to establish a medical geology educational and research program in Africa in order to address these issues. This impressive program at the University of Johannesburg investigates the relationship between

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pertinent geo-environmental variables and specific public health issues through research collaborative projects and training of a new generation of researchers in Africa. The program attracted several postgraduate students from different countries in Africa including South Africa, Ghana, Nigeria, Namibia, and Kenya since it started in 2013. The results of this highly successful training program have been presented at several international conferences and in peer-reviewed journals.

Sessions of Medical Geology at international conferences have been organized at several international conferences such as the European Geoscience Union Meeting (EGU), Vienna (2018), which was attended by several postgraduate students from the University of Johannesburg group. See Chap. 27

A major success story from Turkey is described in Chap. 28. It is incumbent upon medical geology practitioners to reach out to students, science faculties, decision-­makers, and the biomedical/public health communities to promote this emerging discipline. Perhaps the most successful of these efforts has taken place in Turkey where medical geology courses have been offered in four medical and ten engineering faculties. As a result of these outreach efforts by the Turkish medical geology community, for the past decade, there has been robust interactions with scientists from many disciplines and collaborative research on groundwater quality, asbestos, radon, arsenic, mesothelioma, fluorosis, etc.

Chapter 26

A Guide to the Medical Geology Literature Olle Selinus, Robert B. Finkelman, Naomi Ty Asha Nichols, and Kreg Walvoord

Abstract  Medical geology (geology and health) is one of the most diverse, multidisciplinary scientific fields having practitioners from the geosciences, public health, epidemiology, toxicology, environmental health, medical geography, and occupational health, just to name a few of the many disciplines that are relevant to this field. Moreover, these researchers are working in more than 100 countries publishing their research in hundreds of geographically and scientifically diverse journals. This diversity, though healthy, makes it difficult to keep up with current, relevant, research papers. This chapter informs on many different paths in getting information on medical geology. Keywords  Medical geology · Geology and health · Dissertations · Theses · Journals

26.1  Background A survey of several hundred articles in Google Scholar and PubMed using the key words “geology and health” and “medical geology” published since 2006 revealed more than 300 articles in 166 different journal outlets (Finkelman and O’Connell 2016). GeoRef added 120 unique references and ScienceDirect added another 65. The articles appeared in journals directed to audiences in general science, geology/ geochemistry, mineralogy/mining, soil science, hydrology, medical science/public health, nutrition, radiation/hazardous materials, occupational health, environmental science, agronomy, geography, chemistry, physics, and archeology. Though many of the journals are international in scope, articles appeared in journals published in Austria, Australia, China, France, Germany, Hungary, Indonesia, Iran, Japan, Netherlands, Pakistan, Romania, Russia, Serbia, South Africa, Sri Lanka, Sweden, Turkey, UK, and the USA. Table 26.1 lists just a few of the relevant medical geology O. Selinus (*) Linneaus University, Kalmar, Sweden R. B. Finkelman · N. T. A. Nichols · K. Walvoord University of Texas at Dallas, Richardson, TX, USA e-mail: [email protected]; [email protected]; [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_26

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Table 26.1 Examples of recent medical geology publications in less frequently searched publications Baxter PJ, Horwell CJ (2015) Impacts of eruptions on human health. In: The Encyclopedia of volcanoes, 2nd edn. pp 1035–1047 Bhat MY, Mir RA (2014) Medical Geology: A case study of Kashmir: The Journal of Central Asian Studies, v. 21, p. 109–118 Bjørklund, G., Christophersen, O.A., Chirumbolo, S., Selinus, O., Aaseth, J., 2017. Recent aspects of uranium toxicology in medical geology. Environmental Research.156 (2017), 526–533 Boulos, M. N. K., and Le Blond, J., 2016, On the road to personalised and precision Geomedicine: Medical Geology and a Renewed Call for Interdisciplinarity: International Journal of Health Geographics, v. 15, no. 1, doi: 10.1186a/s12942-016-0033-0 Buia, G. and Radulescu, M., 2012, Medical Geology and life cycle assessment—the missing link: Romanian Journal of Mineral Deposits, v. 85, no. 2, p. 40–43 Duffin, C. J., 2013, Geology as medicine and medics as geologists: Geological Society of London, Special Publications, v. 375, no. 1, p. 1–6, doi: https://doi.org/10.1144/sp375.29 Elewa, A. M., 2009, Medical Geology and mining hazards in Africa: Journal of Geology and Mining Research: Journal of Geology and Mining Research, v. 1, no. 7 Golekar, R. B., Baride, M. V., and Patil, S. N., 2014, Geomedical health hazard due to groundwater quality from Anjani–Jhiri River Basin, Northern Maharashtra, India: International Research Journal of Earth Sciences, v. 2, n. 1, p. 1–14 Gomes, C., and Silva, J., 2007, Minerals and clay minerals in Medical Geology: Applied Clay Science, v. 36, n. 1–3, p. 4–21, doi: https://doi.org/10.1016/j.clay.2006.08.006 Goovaerts, P., 2014, Geostatistics: A common link between medical geography, mathematical geology, and medical geology: Journal of the Southern African Institute of Mining and Metallurgy, v. 114, n. 8, p 605–613 Guidotti, T. L., 2009, Advice to a student interested in “Medical Geology”: Archives of Environmental & Occupational Health, v. 64, n. 3, p 213–214, doi: https://doi. org/10.1080/19338240903240533 Hahn. E. J., Gokun, Y., Andrews W. M., Jr., Overfield, B. L., Wiggins, A., and Ravens, M. K., 2015, Radon potential, geologic formations, and lung cancer risk: Preventive Medicine Reports, v. 2, p 342–346, doi: https://doi.org/10.1016/j.pmedr.2015.04.009 Hamza, S., Naseem, S., Bashir, E., Rizwani, G. H., and Hina, B., 2013, Trace element geochemistry of Manikara zaopta (L.) P. Royen, fruit from Winder, Balochistan, Pakistan in perspective of Medical Geology: Pakistan Journal of Pharmaceutical Sciences, v. 26, n. 4, p 805–811 Hansell, A. L., Horwell, C. J., and Oppenheimer, C., 2006, The health hazards of volcanoes and geothermal areas: Occupational and Environmental Medicine, v. 63, n. 2., doi: 63/2/149 Jun-lan, C., 2009, Applied Medical Geology to practice: Journal of Geological Hazards and Environment Preservation, v. 2, p 132–134 Kopani, M., Kopaniova, A., Trnka, M., Caplovicova, M., Rychly, B., and Jakubovsky, J., 2016, Cristobalite and hematite particles in human brain: Biological Trace Element Research, p 1–6, doi: https://doi.org/10.1007/s12011-016-0700-9 Liang, L. I., Yong-hui, A. N., Xu-feng, H.E., and Xio-feng, J. I. A., 2010, An analysis of the characteristics of geological environment in the Kashin-Beck disease area in the Ruoergai County of Sichuan Province: Hydrogeology & Engineering Geology, v. 4 Li, S., Xiao, T., and Zheng, B., 2012, Medical Geology of arsenic, selenium, and thallium in China: The Science of the Total Environment, v. 421–422, doi: 10.10.16/j.scitotenv.2011.02.040 (continued)

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Table 26.1 (continued) Molla, Y. B., Wardrop, N. A., Le Blond, J. S., Baxter, P., Newport, M. J., and Atkinson, P. M., and Davey, G., 2014, Modeling environmental factors correlated with podoconiosis: a geospatial study of non-filarial elephantiasis: International Journal of Health Geographics, v. 13, doi: https://doi.org/10.1186/1476-072X-13-24 Momoh, A., Mhlongo, S. E., Abiodun, O., Muzerengi, C., and Mudanalwo, M., 2013, Potential implications of mine dusts on human health: A case study of Mukula Mine, Limpopo Province, South Africa: Pakistan Journal of Medical Sciences, v. 29, no. 6, doi: https://doi.org/10.12669/ pjms.296.3787 Rikhvanov, L. P., Baranovskaya, N. V., and Sudyko, A. F., 2013, Chemical elements in human body as the basis for realization of ideas of medical geology: Gornyi Zhurnal (Mining Journal), v. 3, p 37–42 Rokade, V. M., 2012, Medical Geology: Integrated study of geochemistry and health: World Journal of Applied Environmental Chemistry, v. 1, no. 1, p. 35–41 Tang, Q., Liu, G., Zhou, C., Zhang, H., and Sun, R., 2013, Distribution of environmentally sensitive elements in residential soils near a coal-fired power plant: potential risks to ecology and children’s health: Chemosphere, v. 93, no. 10, p. 2473–2479, doi: https://doi.org/10.1016/j. chemosphere.2013.09.015 Weiguo, Z., 2012, Medical Geology development role of the use of coal: Science & Technology Information, v. 29

articles in journals not typically consulted by geoscientists or biomedical/public health researchers. Table 26.2 contains a list of books on various aspects of medical geology. There are also chapters in books (e.g., Randive 2013; Finkelman et  al. 2017). In addition, there are books on medical geology in languages other than English. For example, there are books or translations of medical geology books in Chinese, Portuguese, Farsi, Hindi, Spanish, and Swedish. Also keep in mind that there are numerous books on the health impacts of elements such as arsenic and mercury; minerals such as asbestos and quartz; fossil fuel use; and geologic phenomenon such as volcanic eruptions and ambient dust storms. To help medical geology practitioners keep up with this diverse, widespread literature, we recommend that the organizations serving this discipline provide, in their newsletters and on their websites, periodic comprehensive bibliographies gleaned from key search engines. Such compilations would provide a very useful service to their membership and also benefit the organizations by identifying potential members and conference attendees. Lacking such a useful service it is incumbent upon the researcher to conduct a thorough search of the literature to locate all publications relevant to their research topic and ultimately to their publications. For the benefit of those students and young researchers interested in pursuing medical geology issues, we are providing some guidelines on how best to conduct these searches. However, we recommend that you first consult your library and librarian for advice. They undoubtedly will know shortcuts that will make the search easier, more efficient, and more productive.

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Table 26.2  Books on medical geology (Fig. 26.1) Brevik, E. C. and Burgess, L. C., (editors), 2013, Soils and Human Health. CRC Press, 391 p Censi, P., Darrah, T. H, and Erel, Y., (editors), 2013, Medical Geochemistry. Springer, 194 p Centeno, J. A., Finkelman, R. B., and Selinus, O., 2016, Medical Geology: Impacts of the natural environment on public health. MDPI, Basel, 238 p Dissanayake, C. B. and Chandrajith, R., 2009, Introduction to Medical Geology. Springer, 297 p Dobrzhenetskaya, L., 2016, Minerals & Human Health. Cognella Academic press, 322 p Duffin, C. J., Moody, R. T. J. and Gardner-Thorpe C., (editors), 2013, A History of Geology and Medicine. Special Publication 375. Geological Society, London. 490 p Gomes, C. de S. F. and Silva, J. B. P, 2006, Minerals and Human Health: Benefits and Risks. Self-published in English and Portuguese Guthrie, Jr. G. D. and Mossman, B. T., (editors), 1993, Health Effects of Mineral Dusts. Reviews in Mineralogy, Vol. 28. Mineralogical Society of America. 584 p Komatina, M., 2004, Medical Geology. Elsevier. 508 p Lag, J, 1990, Geomedicine. CRC Press. 278 p Mori, I. and Ibaraki, H. (editors), 2017, Progress in Medical Geology. Cambridge Scholars Publishing. 329 p Selinus, O., Alloway, B., Centeno, J. A, Finkelman, R. B., Fuge, R., Lindh, U., Smedley, P., eds., 2005, Essentials of Medical Geology, Elsevier, New York, 812 p Selinus, O., Alloway, B., Centeno, J. A, Finkelman, R. B., Fuge, R., Lindh, U., Smedley, P., eds., 2006, Essentials of Medical Geology. Chinese Edition. Translated by Zheng Baoshan and Wang BinBin. Science Press, Beijing. 708 p Selinus, O., Alloway, B., Centeno, J. A, Finkelman, R. B., Fuge, R., Lindh, U., Smedley, P., eds., 2013, Essentials of Medical Geology, Revised Edition, Springer. 805 p Selinus, O., Centeno, J. A., and Finkelman, R. B., (editors.), 2010, Medical Geology—A Regional Synthesis. Springer, 392 p Sahai, N. and Schoonen, M. A. A., (editors), 2006, Medical Mineralogy and Geochemistry. Reviews in Mineralogy & Geochemistry, Vol. 64. Mineralogical Society of America.322 p Skinner, H. C. and Berger, A. R., (editors), 2003, Geology and Health: Closing the Gap. Oxford University Press, New York. 179 p Tan, J., Peterson, P. J., Ribang, L., and Wang, W. (editors), 1990, Environmental Life Elements and Health. Science Press, Beijing. 390 p

26.2  Most Useful Search Engines Google Scholar: https://scholar.google.com/ GeoRef: https://pubs.geoscienceworld.org/georef ScienceDirect: https://www.sciencedirect.com/ Medline/PubMed: https://www.nlm.nih.gov/bsd/pmresources.htm National Library of Medicine: http://nlm.nih.gov/ ResearchGate: https://www.researchgate.net/ Scopus: https://www.scopus.com/home.uri Log-in required GeoScience World: https://pubs.geoscienceworld.org/ Web of Science: https://clarivate.com/products/web-of-science/ Wiley Online Library: https://onlinelibrary.wiley.com/

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Fig. 26.1  Examples of books dealing with medical geology

26.3  What Are Examples of Useful Key Word? In any literature search, using appropriate key words is critical. However, some unqualified terms could lead to overload. Terms like arsenic and many other trace elements, cancer and other common diseases, quartz, asbestos and other minerals, China and other countries will bring many thousands of references. So what are the appropriate key words? Linking the geologic material or geologic process with a specific health issue such as silicosis, and/or the geographic region plus “medical geology” or “geology and health” or “geomedicine” or “environmental health” or “geology and medicine” can be effective. Some key words will generate many thousands of unwanted references. “Minerals and health” will spew out millions of references on nutrition. Others include “element X and health” “natural radioactivity” “naturally occurring organics and health” “ambient dust and health.” Other sources of information on medical geology include websites (Table 26.3), newsletters (Table 26.4), journals (Table 26.5), conference proceedings (Table 26.6), databases (Table 26.7), atlases (Table 26.8), and theses and dissertations (Table 26.9).

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Table 26.3  Websites containing medical geology information International Medical Geology Association (IMGA) http://www.medicalgeology.org/pages/ public/imga/page_imga.htm Society for Environmental Geochemistry and Health (SEGH) http://www.segh.net/ Geological Society of America’s Geology & Health Division http://rock.geosociety.org/ GeoHealth/index.html GeoHealth: The American Geophysical Union (AGU) platform on Geology and Health The Geological Surveys Database (https://statesurveys.americangeosciences.org) The International Volcanic Health Hazard Network (IVHHN) http://www.ivhhn.org/ Medical Geology Facebook Group, University of Johannesburg, South Africa. https://www. facebook.com/groups/240276306461498/ Table 26.4  Medical geology newsletters GSA G&H Division http://rock.geosociety.org/GeoHealth/newsletters.html U.S. Geological Survey GeoHealth Newsletter https://www.usgs.gov/media/images/geohealth-usgss-environmental-health-newsletter IMGA Newsletters http://www.medicalgeology.org/pages/public/publications/page_ Publications.htm Table 26.5  Journals commonly containing articles on medical geology Environmental Geochemistry and Health: https://link.springer.com/journal/10653 Journal of Health and Pollution: http://www.journalhealthpollution.org/?code=bsie-site GeoHealth Journal: https://agupubs.onlinelibrary.wiley.com/ International Journal of Environmental Research and Public Health — Open Access Journal: https://www.mdpi.com/journal/ijerph Applied Geochemistry Science of the Total Environment Environmental Toxicology And Pharmacology International Journal of Environment and Pollution International Journal of Occupational Medicine and Environmental Health Chemosphere Journal of Toxicology and Environmental Health Bulletin of the World Health Organization Current Environmental Health Reports Environmental Science & Technology Environment international Toxicology Environmental Health Perspectives Environmental Health Human and Ecol. Risk Assess

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Table 26.6  Examples of medical geology conference proceedings Natural Science and Public Health—Prescription for a Better Environment, 2003, Abstracts from the conference. U.S. Geological Survey Open-File Report 03-097. Unpaginated Proceedings of the Workshop on Medical Geology, 2004, IGCP-454. Special Publication No. 83. Geological Survey of India. 418 p SEGH 2010 International Conference and Workshops of the Society for Environmental Geochemistry and Health on Environmental Quality and Human Health, 2010, Conference Schedule & Abstracts. National University of Ireland, Galway, Ireland. 193 p 2005 International Workshop on Medical Geology in Brazil. Rio de Janeiro.2010. Editors Da Silva, Figueiredo, De Capitani, da Cunha 206 pp Articles of the First International Symposium on Medical Geology/Iran.2010. Geological Survey of Iran.276 pp Wragg, J., Watts, M.J, & Cave, M.R. (2009). Practical applications of medical geology, 19–20 March 2009: Book of abstracts. British Geological Survey Internal Report 51 p Table 26.7  Examples of databases to use in medical geology research Reimann, C., U. Siewers, T. Tarvainen et al. 2003: Agricultural Soils in Northern Europe: A Geochemical Atlas.—Geologisches Jahrbuch, Sonderhefte, Reihe D, Heft SD 5. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart Salminen, R. (Chief-editor), M.J. Batista, M. Bidovec, A. Demetriades, B. De Vivo, W. De Vos, M. Duris, A. Gilucis, V. Gregorauskiene, J. Halamic, P. Heitzmann, A. Lima, G. Jordan, G. Klave, P. Klein, J. Lis, J. Locutura, K. Marsina, A. Mazreku, P.J. O’Connor, S.Å. Olsson, R.-T. Ottesen, V. Petersell, J.A. Plant, S. Reeder, I. Salpeteur, H. Sandström, U. Siewers, A. Steenfelt, T. Tarvainen 2005: Geochemical Atlas of Europe. Part 1—Background Information, Methodology and Maps. Geological Survey of Finland, Espoo. http://weppi.gtk.fi/ publ/foregsatlas/ Reimann, C., Birke, M., 2010. Geochemistry of European Bottled Water. Scheizerbartsche. Complete database on a CD in the book Table 26.8  Examples of medical geology atlases Tan Jianan, 1985. The atlas of endemic diseases and their environments in the People’s Republic of China. Science Press. 194 pp Tan Jianan, 2000. The atlas of plague and its environment in the People’s Republic of China. Science Press.206 pp National medical geology atlas of Iran. Ministry of Industry and Mine, Geological Survey of Iran, Medical Geological Management. 300 pages Geo Veterinary atlas of Iran. Ministry of Industry and Mine, Geological Survey of Iran, Medical Geological Management. 303 maps Navi, M. 2007. Elements and diseases atlas of Iran. National Geoscience Database of Iran

26.4  Medical Advice for Geoscientists Linking geology to medical pathology/disease requires careful and thorough research practices and epidemiologic analyses. This can be very difficult because of confounding factors within the human study population as well as the geologic source of the potential etiologic factor. The abovementioned references are a very useful start but early consultation with public health personnel or physicians is vital.

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Table 26.9  Examples of master’s theses and PhD dissertations PhD Dissertations Berger, T. 2016, Fluoride in surface water and groundwater in southeastern Sweden. Linnaeus University Dissertations 253:2016. Kalmar Sweden Chakraborty, J. 2017, Exploring the link between low-rank coal derived organic compounds in the Carrizo-Wilcox Aquifer and incidence of kidney disease in East Texas. University of Texas at Dallas Faltmarsch, R. 2010, Biogeochemistry in acid sulphate soil landscapes and small urban centres in Western Finland. Abo Academy, Finland Kneen. M. A. 2104, Gold mine dumps in Witwatersrand and the associated health risk to exposed population. University of Texas at Dallas Kousa, A. 2008, The regional association of the hardness in well waters and the incidence of acute myocardial infarction in rural Finland. University of Kuopio, School of Public Health and Clinical Nutrition, Finland, 442 Linde, M. 2005, Trace metals in urban soils—Stockholm as a case study. Swedish university of Agricultural Sciences. 2005:111 Ljung, K. 2006, Metals in urban playgrounds soils. Distribution and bioaccessibility. Swedish university of Agricultural Sciences. 2006:81 Londono-Arias, S. C. 2016, Ethnogeology at the Core of Basic and Applied Research: Surface Water Systems and Mode of Action of a Natural Antibacterial Clay of the Colombian Amazon Morrison K. D. 2015, Unearthing the Antibacterial Activity of a Natural Clay Deposit. Arizona State University Nharghbu Ktso, 2018, Balneology and medical hydrogeology of the Nigerian oilfields. A medical geology initiative Ojeda, A. S. 2017, Integration of geochemistry, toxicology, and epidemiology to evaluate the lignite-water hypothesis in the United States Gulf Coast Region. University of Oklahoma Roos, P. 2013, Studies on metals in motor neuron disease. Karolinska Institute, Stockholm, Sweden Rosborg, I. 2005, Mineral element contents in drinking water—aspects on quality and potential links to human health. Lund University, Sweden Shelembe R. 2019, The Pilanesberg Alkaline Complex and the Rustenburg Layered Suite: possible sources of potentially harmful elements excess in groundwater and soil and health impact on North West Province communities, South Africa Sohel, N. 2010, Epidemiological and spatial association between arsenic exposure via drinking water and morbidity and mortality. Uppsala University, Uppsala, Faculty of Medicine 549 Tomasek, I. (2018). Environmental and anthropogenic factors affecting the respiratory toxicity of volcanic ash (Doctoral dissertation, Durham University). http://etheses.dur.ac.uk/12671/1/ TomasekInes_PhD_2018.pdf Voutchkova, D. 2014, Iodine in Danish Groundwater and Drinking Water. Aarhus University, Denmark Master’s Theses Gevera P. 2019, The occurrence of high fluoride in groundwater and its health implications in Nakuru County in the Kenyan Rift Valley University of Johannesburg Kambunga S. 2018, Geophagy during pregnancy and its possible health impacts: A case study from Onangama village, northern Namibia. University of Johannesburg Koki, C. 2017, Investigating geogenic lead contamination and its associated health effects in Kilifi Area, Kenya. University of Johannesburg (continued)

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Table 26.9 (continued) Munyangane, L. P. 2015, Potential harmful trace elements (PHTEs) in the groundwater of Greater Giyani, Limpopo Province, South Africa: Possible health implications. University of Johannesburg Pretorius C, 2019, The possible geological sources of chronic copper poisoning of sheep in some specific farms of the Karoo Basin, South Africa. University of Johannesburg Sanyaolu Olufunke M. 2018, Iodine and the prevalence of goiter in Nigeria: a case study from Badagry Lagos, Southwest Nigeria. University of Johannesburg Your library may have access to ProQuest (https://www.proquest.com/libraries/academic/ dissertations-theses/) which offers access to an extensive global archive of dissertations and theses

References Finkelman RB, O’Connell RL (2016) Comprehensive bibliographies: an essential service to the geology and health community. Geological Society of America Abstracts with Programs, vol 48, no. 7 Finkelman RB, Orem WH, Plumlee GS, Selinus O (2017) Applications of geochemistry to medical geology. In: Environmental geochemistry, vol 17, pp 435–465 Randive KR (2013) Elements of geochemistry, geochemical exploration, and medical geology. Research Publishing, 464 p

Chapter 27

Medical Geology in Africa: An Example of a Successful Educational and Research Initiative at the University of Johannesburg, South Africa Hassina Mouri

Abstract  The African continent is characterised by a very complex and dynamic geological history and evolution including frequent earthquakes and volcanic eruptions in tectonically active regions. This is in addition to water toxicity due to interaction with the geological environment including rocks and soil as well as air pollution due to dust storms especially in the dry parts of the continent. Furthermore, the continent is known for its mining activities and petroleum exploration, which enhance the release of chemical elements and dust into the environment. Considering the possible health impacts of these natural geo-environmental and anthropogenic materials, factors and processes on humans and animals, it has become necessary and urgent to establish a Medical Geology educational and research programme in Africa in order to address these issues. This programme led by postgraduate students investigates the relationship between pertinent geo-environmental variables and specific public health issues through research-collaborative projects and training of a new generation of researchers in Africa. The programme attracted several postgraduate students from different countries in Africa including South Africa, Ghana, Nigeria, Namibia and Kenya since it started in 2013. The results of this highly successful training programme have been presented at several international conferences and in peer-reviewed journals. Keywords  Medical Geology · Africa · Postgraduate students · University of Johannesburg

H. Mouri (*) Department of Geology, Faculty of Science, University of Johannesburg, Johannesburg, South Africa e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_27

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27.1  Introduction and Objectives of the Initiative Although there has been growing development of Medical Geology throughout the world, it is in Africa that research in this field would be highly relevant as there are many health problems throughout the continent, which might be caused by natural materials, factors and processes as well as anthropogenic activities (such as mining activities and petroleum exploration). However, it is in Africa that the field is still not yet well developed. In order to fill this gap, a dynamic and highly successful medical geology education initiative has been developed at the University of Johannesburg, South Africa, since 2013. The initiative consists mainly of training postgraduate students on relevant projects related to the field of Medical Geology at the level of a Master’s degree (2-year research project) and has recently evolved into training PhD students (3-year project) as well. The main objectives and the possible socio-economic impacts of this initiative include: • Providing adequate education and training for a new generation of young researchers who will lead in this multidisciplinary field in Africa, • Helping to better understand the geo-environment and its impacts on human and animal health that may lead to mitigation and recommendations of possible solutions, • Providing education to the population (especially those who live in rural areas) in which the Medical Geology knowledge informs them of the serious possible health hazards that can be caused by hidden (natural) geological problems as well as those which are caused or enhanced by anthropogenic factors including, for example, mining activities, • Broadening our understanding of the possible causes of many common health issues (such as certain types of cancer, asthma, thyroid dysfunction, fluorosis, mental retardation), which are common in the African continent. This can contribute to the prevention of further health risks and even loss of life in future generations. Finding the sources and solutions of these health problems can also help to limit their social and economic impacts.

27.2  W  hy Medical Geology Initiative in the Postgraduate Curriculum? Students at the postgraduate level should have more than just technical skills in various subjects within geology. They should know how this knowledge is integrated and connected not only within the discipline, but also to other disciplines such as environmental, health and social sciences. They should also know how the geological knowledge gained can be translated and applied for the benefit of their communities and society in general. This is in line with the vision of the International Council for Science (ISC) “Science as a global public good” (https://icsu.org/). It is

27  Medical Geology in Africa: An Example of a Successful Educational and Research… 867

therefore on this basis, that the development of Medical Geology, with a focus on Africa had been initiated. After establishment at the University of Johannesburg, the subject soon became very popular amongst students from all over Africa (as there was a rapidly increasing number of members on the social media such as Facebook platform created specifically for the group). This demonstrates the important relevance and the need of the discipline in the student’s curriculum. The success of this initiative is demonstrated by the number of students enrolled since the inception of the discipline and the number of national and international experts involved so far (Tables 27.1 and 27.2).

27.3  Why Focus on Africa? It is important to teach our students to understand that geology is not just about mining of natural resources as it is perceived by many people, especially in Africa, but it is also about the well-being of the society. It is very important for students to realise that by mining minerals and coal and exploiting petroleum resources to satisfy the economic needs of a nation, a number of harmful elements can be released into the environment, which can cause a range of health issues to the nearby communities. This is in addition to the natural geological occurrences, processes and factors.  Hence, it is important to learn about the possible  health risks  associated with such antropogenic and geogenic issues and how to contribute to solutions. This is valid in particular for the African continent, where people live in very close contact with their natural environment and actively involved in mining activities. From a geological point of view, the African continent is known for its complex and dynamic geological history and evolution including frequent earthquakes, volcanic eruptions in tectonically active regions such as the African Rift Valley. This is in addition to pervasive dust storms in arid parts of the continent causing air pollution, water toxicity due to interaction with the geological environment and naturally occurring radioactive formations. Furthermore, the continent is known for the widespread mining activities for mineral resources as well as petroleum exploration, which enhance the release of potentially harmful chemical elements and minerals into the environment. All these naturally occurring, as well as anthropogenic, processes, materials and factors are known to have short- and/or long-term impacts on humans’ and animals’ health and the ecosystem in general. From a health point of view, the non-communicable (NCDs) diseases, such as cardiovascular diseases, cancer, chronic respiratory tract diseases and diabetes, account for more than 50% of all deaths in some African countries (e.g. Seychelles 59%, Algeria 56%) (WHO, 2018). However, the primary causes of such diseases and mortality in general remain unclear in many cases and attention is mostly focussed on risk factors and treatment rather than addressing possible causes. Therefore, in order to ascertain the environmental causes for the wide range of health issues occurring in Africa, it is important to integrate Earth Science with

2015

2017

2017

2017

UJ

UJ

UJ

UJ

UJ

3. Koki (Kenya) (FT)

4. Kambunga (Namibia) (FT) 5. Sanyaolu (Nigeria) (FT) 6. Sihlahla (SA) (FT)

7. Mekgoe (SA) (FT)

2017

2017

8. Moshupya (SA) (FT) Wits

9. Ahlijah (Ghana) (FT) UJ

2017

2015

2. Gevera (Kenya) (FT) UJ

2020

2019 (73%)

2019 (distinction)

2019 (distinction)

2019 (distinction)

2019 (distinction)

2017

2017 (distinction)

Student name and country Inst. Year start Year end Completed and on-going MSc projects (FT=full time, PT = part time) 1. Munyangane UJ 2013 2015 (SA) (PT)

Potentially harmful trace elements (PHTEs) in the groundwater of Greater Giyani, Limpopo Province, South Africa: possible health implications The occurrence of high fluoride in groundwater and its health implications in Nakuru County in the Kenyan Rift Valley Investigating geogenic lead contamination and its associated health effects in Kilifi Area, Kenya Geophagy during pregnancy and its possible health impacts: A case study from Onangama village, northern Namibia Iodine and the prevalence of endemic goiter in Nigeria: A case study of Badagri, Lagos SW Nigeria Assessment of extraction and bioavailability and health effects of some potential harmful elements in environmental matrices collected from selected farms located in Eastern Cape Province High fluoride-concentration in groundwater, related health issues and remediation using rooibos tea loaded with zr/ce oxide The uranium and radon gas concentration and impact on human health: A case from abandoned gold mine tailings in the West Rand area, Krugersdorp, South Africa Assessment of major and trace elements and possible health implication of geophagic clays: examples from Amfoega in Volta region and Mfensi-Adankwame in Ashanti region, Ghana

Project title

Table 27.1  List of the Medical Geology Postgraduate students and related information since 2013

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UJ

UJ

15. Shelembe (SA) (PT)

16. Sanyaoulu (Nigeria) (FT)

UJ

On-going PhD 14. Gevera (Kenya) (FT)

2019

2013

2018

2019

UJ

13. Malepe (SA) (FT)

2022

2021

2021

2021

2020

2017

Year end 2020

2020

Year start 2017

2017

Inst. UJ

11. Tshishonga UNIV (SA) (FT) 12. Okunhle (SA) (FT) NMU

Student name and country 10. Lupita (SA) (FT)

(continued)

Natural contaminants in soil, water and food from Makueni County, south eastern Kenya: health implications and risk factors assessment on the community The Pilanesberg Alkaline Complex and the Rustenburg Layered Suite: possible sources of potentially harmful elements excess in groundwater and soil and health impact on North West Province communities, South Africa Investigating the impact of mining activities on human health and environment: the case study of Ogun State, Southwest Nigeria

Project title Natural Cr(VI) occurrence in ground water: An example from the Bushveld Igneous Complex, South Africa, health impact and removal using chitosan Arsenic in groundwater, health impacts and possible remediation measures: A case study from Mopani district Giyani, South Africa Occurrence and distribution of selected uranium (U), molybdenum (Mo) and mercury (Hg) bearing minerals in Karoo sequences as potential sources for toxic elements in ground-and-surface water, and their possible health impacts across the south central Karoo Basin Investigation of geophagia around Fetakgomo Tubatse Local Municipality Areas in Limpopo Province, South Africa: Possible human health benefits and effects

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Inst. UJ

Year start 2020

Year end 2023

Project title Dust and respiratory impacts: a case study from abandoned mines around Johannesburg area, South Africa

This table contains the list of the Postgraduate students in Medical Geology, including the following information:1. Names of the students, country of origin, year of registration and year of graduation as well as the titles of their projects which reflect on the success of the initiative (completion on time) uniqueness of the research activities conducted under the initiative, which are of a Pan-African nature. The titles of the projects also reflect on the diversity and the multidisciplinary natures of these research activities and the focus on Africa2. The table also shows the rapid growth of the medical geology in Africa initiative @ UJ starting with 1 part time MSc student in 2013 to 16 MSc and PhD students since then3. The table contains also a reference to those who obtained their degree with distinction and indication of the excellent quality of the work conducted under this initiative

Student name and country 17. Asiashu Mudau (SA) (FT)

Table 27.1 (continued)

870 H. Mouri

27  Medical Geology in Africa: An Example of a Successful Educational and Research… 871 Table 27.2  List of collaborators involved in the Medical Geology initiative at the University of Johannesburg, South Africa Name Expertise/affiliation/country 1.  Prof. K. Pillay Chemistry/University of Johannesburg/SA 2.  Prof. P. Nomngongo Chemistry/University of Johannesburg/SA 3.  Dr. D. Rose Geology/University of Johannesburg/SA 4.  Prof. T. Abiye Hydrogeology/Witwatersrand/SA 5.  Dr. MGT Kwata Water and Environment Research/Council for Geosciences/ SA 6.  Prof. J. Gumbo Environmental Science/University of Venda/SA 7.  Prof. M. de Wit Earth Science/NMMU/SA 8.  Dr. M. Maronga Dentist/St. Mary's Rift Valley Mission Hospital, Gilgil/ Kenya Water and Wastewater Engineering/Aurecon/SA 9.  Dr. M. Levin 10.  Dr. M. Strauss Radiation/PARC RGM—Radon Gas Monitoring/SA 11.  Dr. R. Strydom Radiation/PARC RGM—Radon Gas Monitoring/SA 12.  Dr. M. van der Merwe Dentistry/Private practice/SA 13.  Mr. I. Hasheela Field Geology/Geological Survey of Namibia/Namibia 14.  Dr. P. Njuru Geochemistry/South Eastern Kenya University/Kenya 15.  Ms. Nakakuwa General Nursing, University of Namibia/Namibia 16.  Prof. AM. Gbadebo Geochemistry/Federal University of Agriculture, Abeokuta, Ogun State/Nigeria 17.  Prof. G. Okunlula Economic Geology/Ibadan University/Nigeria 18.  Prof. K. Dowling Mining environmental and health/Federation University/ Australia Water and soil geochemistry and health/British Geological 19.  Dr. M. Cave Survey/UK 20.  Prof. O. Selinus Founder Medical Geology/Linnaeus University, Kalmar/ Sweden 21.  Prof. C. Candeias Heavy metals and health/Aveiro University/Portugal 22.  Prof. R. Finkelman Founder Medical Geology/University Texas, Dallas/USA 23.  Prof. Ngila Nano-technology-heavy metals in water/African Academy of Science/Kenya

Public Health through Medical Geology studies. It is only by understanding the geological history and background of our environment, that we will be able to contribute towards a better and deeper insight into the understanding of the range of natural hazards that can affect (directly or indirectly) our health and that of the ecosystem. This understanding may result in mitigation, and even prevention, of some of these widespread and serious health problems and thus contribute to the well-being of our community in line with the 2030 United Nations agenda for Sustainable Development Goals (SDGs) published in 2015.

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27.4  What Are the Outcomes So Far? 27.4.1  U  niversity of Johannesburg (UJ) the Main Host of Postgraduate Students from Africa Since the start of this initiative, the University of Johannesburg (UJ) became the main destination in the African continent for students interested in Medical Geology. The University of Johannesburg hosts, by far, the largest number of postgraduate students coming from several African countries including South Africa, Ghana, Nigeria, Kenya and Namibia (Table 27.1) to train on projects in this field. Several national and international experts in various fields relevant to Medical Geology were/are involved (Table 27.2) in the supervision/co-supervision of these students in order to offer them the adequate training.

27.4.2  Summary of Some Research Projects and Results The projects conducted so far deal mostly with the establishment of the relationship between environmental geochemistry and mineralogy and that of human and animal health in Africa. In addition, one of the important aspects, which is also considered under the programme, is the possible remediation conducted in collaboration with the departments of environmental science and applied chemistry. Below is a summary of some examples of completed projects and outputs: • Toxic trace elements in drinking water boreholes in the rural Greater Giyani area, South Africa. This study enabled the discovery of high levels of arsenic in these boreholes, which are due to the presence of arsenopyrite in the underlying geological formation. The results are published by Munyangane et al. (2017, 2018). This study was followed by an ongoing MSc project by Tshishoga, Venda University, looking at possible remediation using ceramic filters produced by the local communities. • High fluorine and dental fluorosis prevalence in Nakuru area, Kenyan Rift Valley. This study enabled us to establish for the first time a clear link between the high fluoride contents and dental fluorosis as well as the spatial distribution (using GIS) of the fluoride concentrations in the area. The results of this study were published by Gevera and Mouri (2017 , 2018)  and Gevera et  al. (2018a, b, c, and , . • Geophagy during pregnancy and possible health effects, a case study from Northern Namibia. This study enabled us to discover for the first time high concentrations of a number of toxic elements including arsenic and mercury in the studied material that can be detrimental to the health of the consumers and their unborn babies. This is the first detailed geochemical and mineralogical study of this kind in Namibia despite the high prevalence of the practice. The results of

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•

•

•

•

•

this study were presented in the following publications: Kambunga et al. (2017, 2018a, b, c, 2019a, b). The uranium and radon gas concentration and impacts on human health, a case study from abandoned gold mine tailings in the West Rand area, Krugersdorp, South Africa. The results of the study showed that mine tailings in the area are characterised by high uranium concentrations (up to 149.76 ppm) and high levels of radon (1068.8 Bq/m3). The effective doses received by the public showed a maximum of 10.11 mSv/y which is above the recommended value of 1 mSv/y proposed by National Nuclear Regulator of South Africa and International Commission on Radiological Protection. These doses can present a great health risk to the population living in the area, which may be evidenced by a high frequency of deaths that are related to lung cancer. The results of this study were published by Moshupya et al. (2018a, b, 2019a, b). The prevalence of goitre and possible causes related to drinking water in Badagry-­Lagos, SW Nigeria. The prevalence of endemic goitre is very high in some regions of Africa, especially in iodine-depleted areas, and its prevalence ranges from 1% to as high as 90% amongst African populations as reported in a review by Sanyaolu et al. (2021 and references therein). Based on this information, an MSc study was conducted in the Badagry-Lagos, SW Nigeria, in order to assess the geochemical composition of the drinking water and the possible link to the goitre disease in the area. This study revealed that high concentrations of iodine, lead and arsenic in drinking water are environmental factors that possibly contribute to the occurrences of goitre and other thyroidal dysfunctions in the area. The results were presented  by Sanyaolu et  al. (2017, 2018a, b, c, 2020a, 2021). Occurrence of some naturally occurring potentially harmful elements and their health implications on the population in South-East Kenya. SE Kenya receives limited rainfall and surface water supply leading to high dependence on groundwater for domestic and agricultural purposes. The salinity of the groundwater is reported to be high, which can be associated with some health complications. This warrants a need for detailed geochemical studies to determine all potential harmful elements in the environment. The preliminary results of this study are presented by Gevera et al. (2020a, b, c, 2021). Assessment of extraction, bioavailability and health effects of some potentially harmful elements in environmental matrices collected from selected farms in Eastern Cape Province, South Africa. This project dealt with development of robust analytical techniques in order to properly assess the concentrations and bioavailability of some toxic elements found in the soil and water in very low concentrations, yet enough to cause health issues. The results of this study were presented by Sihlahla et al. (2018a, b, 2019, 2020). Investigating the impact of mining activities on human health and environment: the case study of Ogun State, Southwest Nigeria (ongoing PhD project). The project employs a holistic multidisciplinary approach in assessing the environmental and human (occupational and non-occupational) exposure to potentially

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toxic elements (PTE’s) released into environmental media (soil, water and food) as a result of quarrying activities in the study area. The preliminary results from this ongoing project were  presented at international conferences  (Sanyaolu et al. 2020b, c). • The Pilanesberg Alkaline Complex and the Rustenburg Layered Suite: possible sources of contamination of groundwater and health impact on North West Province communities, South Africa. This is an ongoing part time project led by Refelwi Shelembe, Executive Director at the Council for Geoscience. Some of the preliminary results of this study were included in the the publication by Buck et  al. (2016), and presented at international conferences by  Shelembe et  al. (2012, 2016).

27.4.3  P  resentation of the Initiative at Various Media Platforms In addition to training postgraduate students to conduct research on projects related to Medical Geology in Africa, and to publish and present their results at international conferences, the initiative on Medical Geology at the University of Johannesburg and its relevance in Africa was presented at several international conferences including the biannual International Medical Geology Conferences (Mouri 2015, 2017, 2019), the International Geological Congress (Mouri 2016a ), the Joint International Conference on Environment, Health, GIS and Agriculture, Galway (Mouri 2016b),  the European Geoscience Union Meeting (Mouri 2018a), the International Conference on Women in Science without Borders (Mouri 2018b), the Geological Society of America and South-Central Section—52nd Annual Meeting (Finkelman et al. 2018). This is in addition to several public lectures in South Africa and elsewhere,  publication in  the South African Journal of Science (Mouri 2020a) and educational interviews including the ISET Careers SA Magazine, 2020 Edition (Mouri 2020b).

27.4.4  Other Activities Since starting the initiative, many scientific and community engagements activities were organised, including: • International Symposia on Medical Geology in Africa (ISMGAf): 2 events ISMGAf 1 and 2 were held at the University of Johannesburg in 2014 and 2018, respectively. These events, which consisted of a 2-day short course and 1-day presentations by delegates attracted up to 50 delegates in 2014 and 70 delegates in 2018 (Fig. 27.1). In 2018, the event saw an important increase in the participation of postgraduate students (30  in total) coming from several South African

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Fig. 27.1  Group photograph of the delegates of the 2nd International Symposium on Medical Geology in Africa (ISMGAf 2), held at the University of Johannesburg, South Africa in November 2018

universities including the University of Johannesburg (UJ), the University of Venda (UNIV), the University of Cape Town (UCT), the University of Witwatersrand (Wits), the University of Stellenbosch (US), the University of Pretoria, (UP), Nelson Mandela Metropolitan University (NMMU) and NorthWest University (NWU). The rest of the delegates were researchers, academics and private consultants representing various organisations including the University of Johannesburg (UJ) (Faculty of Health, College of Business and Economics, Departments of Geography and Geology), UCT (Department of Environmental Sciences), NWU (Department of Geology), Council for Geoscience, Anglo American and Harmony Gold. The guests speakers and shortcourse presenters at the two events were from various backgrounds and institutions at national and international levels, including private consultants on uranium-related issues (M.  Levin), public health sector—psychiatry (Ch. Magnus, Flora Hospital, South Africa) and Faculty of Health at NMMU (S.  Olivera, Registered Nurse and Primary Health Care), Montana State University (D.  Keil and J.  Pfau), University of Nevada, Las Vegas (B.  Buck), Federation University Australia (K.  Dowling), the British Geological Survey, UK (M.  Cave) and the Center for Devices and Radiological Health Office of Science and Engineering Laboratories U.S.A. (J. Centeno). The presentations by guest speakers and delegates covered a wide range of topics related to Medical Geology including microbiology, biochemistry, environmental toxicology, immunotoxicology, environmental health, primary health care as well as psychiatry. • Yearly seminars: yearly seminars were held at the University of Johannesburg, during which all postgraduate students present their ongoing projects in the presence of the supervisors and co-supervisors (Fig. 27.2). • Sessions of Medical Geology at international conferences: dedicated sessions on the discipline were organised at several international conferences such as the International Geology Congress (IGC)–Cape Town (2016) and for the first time at the European Geoscience Union Meeting (EGU)-Vienna (2018) which was

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Fig. 27.2  Group photograph of the postgraduate students and some of the collaborators at the end of the year postgraduate meeting held at the University of Johannesburg in November 2018

Fig. 27.3  Group Photograph of the postgraduate students at the European Geoscience Union (EGU) Meeting held in Vienna in April 2018

attended by several postgraduate students from the University of Johannesburg group (Fig. 27.3). • Community engagement activities: since one objective of the Medical Geology discipline in general is increased public awareness, we organised and took part in some community engagement activities, such as a “science week” event organised at the University of Johannesburg for the learners. This event takes place once a year at the Soweto Campus of the University of Johannesburg where thousands of learners from various schools attend. During this event, the Medical Geology postgraduate students presented their projects and explained to the learners what Medical Geology is and how it can benefit the society (Fig. 27.4). Exhibition of books and posters on the medical geology as well as video clips were also presented at the event.

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Fig. 27.4  Group photograph with some postgraduate students and learners during the “Science Week” event held at the Soweto Campus of the University of Johannesburg, May 2017

27.4.5  Awards and Distinctions by the Students Several  MSc students in the Medical Geology postgraduate group 2017–2019 obtained their degree within the minimum stipulated time (2 years) and with distinctions  (Table 27.1). These achievements reflect on the quality of training and the projects conducted, the enthusiasm of the students, as well as the scientific and financial support provided to the students. In addition, Selma Kambuga (MSc student, 2017–2019) won the “Outstanding Student Poster and PICO (OSPP) award at the European Geoscience Union Meeting in Vienna (EGU, 2018) and Paballo Moshupya won the best Young Scientist Oral Presentation at the Annual Conference of the Southern African Radiation Protection Association (SARPA) in August 2019. Paballo Moshupya will represent our programme at the SARPA at IRPA (International Radiation Protection Association) conference in Korea in 2020.

27.5  Sponsors The initiative was mainly sponsored by the National Research Foundation of South Africa (NRF) under the Collaborative Postgraduate Training programme (grant number 105294) and Rated Researcher grant to Hassina Mouri, the University of Johannesburg Global Excellence and Stature (GES) Programme, the University of Johannesburg Research Committee (URC) funds, as well as the Faculty of Science, UJ Research Committee (FRC) funds. The events organised were sponsored by the National Research Foundation (NRF), KIC Scientific Event Grant, ISC-Regional

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Office Africa (former ICSU office), International Union of Geological Science (IUGS), International Medical Geology Association (IMGA) Stimulus Chapter award  to Hassina Mouri in 2013, British Geological Survey, Faculty of Science, University of Johannesburg, and with some support from the Geological Society of South Africa (GSSA).

27.6  Concluding Remarks Since the inception of the initiative in 2013, several postgraduate student-led research projects on topics related to Medical Geology in Africa were initiated and completed resulting in a number of publications in peer-reviewed international journals and conferences (references below), while others are still ongoing. This programme clearly demonstrates that Medical Geology has a broad and strong pan-African appeal. Therefore, with dedicated leadership and necessary financial support from national and international organisations and institutions, it can result in activities that stimulate and retain students’ interest and enthusiasm. Acknowledgements  H. Mouri would like to acknowledge the financial support provided by all the sponsors listed above, especially the National Research Foundation-South Africa (NRF) and the University of Johannesburg. Special thanks to Prof JM Illig and the Editors for their constructive comments, which helped to improve the manuscript. All colleagues involved in the initiative are warmly thanked for their very kind support, encouragement and cooperation, which helped in the success of the initiative.

References1 Buck BJ, Londono SC, McLaurin BT, Metcalf R, Mouri H, Selinus O, Shelembe* R (2016) The emerging field of medical geology in brief: some examples. Environ Earth Sci 75: 449. https:// doi.org/10.1007/s12665-­016-­5362-­6 Finkelman RB, Selinus O, Mouri H (2018) Medical geology in Africa: an example of a successful medical geology educational initiative. In: South-Central Section—52nd Annual Meeting. Geological Society of America (GSA) Gevera* P, Mouri H (2017) Natural occurrence of potentially harmful fluoride content in groundwater: an example from Nakuru County, the Kenyan rift valley. In: Seventh International Conference on Medical Geology. Conference Materials, Russia/Publishing House of I.M. Sechenov First MSMU, SD-53, p 87 Gevera* P, Mouri H (2018) Natural occurrence of potentially harmful fluoride contamination in groundwater: an example from Nakuru County, the Kenyan Rift Valley. Environ Earth Sci 77(10):365 Gevera* P, Mouri H, Maronga G (2018a) High fluoride and dental fluorosis prevalence: a case study from in Nakuru area, the Kenyan Rift Valley. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov. 5–7, 2018, Johannesburg, South Africa

 (PS: names in bold and indicated with * are postgraduate students).

1

27  Medical Geology in Africa: An Example of a Successful Educational and Research… 879 Gevera* P, Mouri H, Maronga G (2018b) High fluoride and dental fluorosis prevalence: a case study from Nakuru area, The Kenyan Rift Valley. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, vol 20, p 1422 Gevera* P, Mouri H, Maronga G (2018c) High fluoride and dental fluorosis prevalence: a case study from Nakuru area, The Kenyan Rift Valley. In: Geocongress 2018 Abstract Book, vol 122, p 75 Gevera* P, Mouri H, Maronga G (2019) Occurrence of fluorosis in a population living in a high-­ fluoride groundwater area: Nakuru area in the Central Kenyan Rift Valley. Environ Geochem Health 41(2): 829–840 Gevera* P, Cave M, Dowling K, Njuru P, Mouri H (2020a) A review on the occurrence of some potentially harmful elements in the natural environment: the south-central Kenya region. In: Selinus O, Siegel M, Finkelman R (eds) Practical applications of medical geology (this book) Gevera* PK, Cave M, Dowling K, Gikuma-Njuru P, Mouri H (2020a) Naturally occurring potentially harmful elements in groundwater in Makueni County, South-Eastern Kenya: effects on drinking water quality and agriculture. Geosciences 10(2):62 Gevera* PK, Cave M, Dowling K, Gikuma-Njuru P, Mouri H (2020b) Naturally occurring potentially harmful elements in groundwater in Makueni County, South-Eastern Kenya: effects on drinking water and agriculture. In: 36th International Geological Congress, Delhi, India Gevera* PK. Cave M, Dowling K, Gikuma-Njuru P, Mouri H. (2020c) Public knowledge and perception of drinking water quality and its health implications in the Makueni County, SouthEastern Kenya. Environmental Monitoring and Assessment Journal (Under review) Gevera* P, Cave M, Dowling K, Njuru P, Mouri H (2021) A review on the occurrence of some potentially harmful elements in the natural environment: the south-central Kenya region. In: Selinus O, Siegel M, Finkelman R (eds) Practical applications of medical geology (this book) Kambunga* SN, Mouri H, Candeias C, Hasheela I (2017) Geophagic termite mound soils and their potential health impact on pregnant women in Onangama village, Northern Namibia. In: Seventh International Conference on Medical Geology. Conference Materials, Russia/ Publishing House of I.M. Sechenov First MSMU, M. SD-54, p 86 Kambunga* SN, Mouri H, Candeias C, Hasheela I (2018a) Geophagy during pregnancy and its possible health impact, case study: Onangama village, northern Namibia. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, 20, 1141. Kambunga* SN, Candeias C, Ávila P, Rocha F, Teixeira JP, Hasheela I, Mouri H (2018b) Geophagy during gestation and its potential health impacts: case study in Onangama village, northern Namibia. In: Fourth International Congress on Occupational & Environmental Toxicology, Matosinhos, Porto 24–26 October 2018 Kambunga* SN, Mouri H, Candeias C, Hasheela I, Nakakuwa F. (2018c) Geophagy during pregnancy and possible health effects: a case study from Onangama village, northern Namibia. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov. 5–7, 2018, Johannesburg, South Africa Kambunga* SN, Candeias C, Hasheela I, Mouri H (2019a) Review of the nature of some geophagic materials and their potential health effects on pregnant women: some examples from Africa. Environ Geochem Health 41:2949–2975 Kambunga* SN, Candeias C, Hasheela I, Mouri H (2019b) The geochemistry of geophagic material consumed in Onangama Village, Northern Namibia: a potential health hazard for pregnant women in the area. Environ Geochem Health 41:1987–2009 Moshupya* P, Abiye T, Mouri H, Levin M (2018a) The uranium and radon gas concentration and impact on human health: a case from abandoned gold mine tailings in the West Rand area, Krugersdorp, South Africa. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, vol 20, p 4661 Moshupya* P, Tamiru Abiye T, Mouri H, Levin M (2018b) The uranium and radon gas concentration and impact on human health: a case from abandoned gold mine tailings in the West Rand area, Krugersdorp, South Africa. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov. 5–7, 2018, Johannesburg, South Africa

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Moshupya* P, Abiye T, Mouri H, Levin M, Strauss M, Strydom R (2019a) Assessment of radon levels and impact on human health in a region dominated by abandoned gold mine tailings: a case from the West Rand area, Krugersdorp, South Africa. Geosciences 9:466. https://doi. org/10.3390/geosciences9110466 Moshupya* P, Abiye T, Mouri H, Levin M, Strauss M, Strydom R (2019b) The concentrations of radon and its sources that impacted human health in the West Rand Region, South Africa. In: The South African Radiation Association Conference (SARPA), August, 2019 Mouri H (2015) Medical geology in Africa: case studies. In: Sixth International Conference on Medical Geology, Aveiro, Portugal. 26 July–1 August 2015 Mouri H (2016a) Africa: a natural laboratory for medical geology investigations. In: IGC 34, Cape Town, Aug. 2016 Mouri H (2016b) Medical Geology in Africa. In: ISEH, ISEG & Geoinformatics 2016 Joint International Conference on Environment, Health, GIS and Agriculture, Galway, Ireland, August 14–20, 2016 Mouri H (2017) Africa: a natural laboratory for medical geology investigations. In: Seventh International Conference on Medical Geology. Conference Materials, Russia/Publishing House of I.M. Sechenov First MSMU, M. PL-03, 37 Mouri H (2018a) The relevance of Medical Geology in Africa: some examples. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, vol 20, p 1769 Mouri H (2018b) Medical Geology and its relevance in Africa. In: International Conference on Women in Science without borders, Johannesburg, South Africa Mouri H (2019) Medical Geology in Africa: an example of a successful educational initiative at the University of Johannesburg, South Africa. In: Eighth International Conference on Medical Geology, Guiyang, August 12–15, 2019 Mouri H (2020a) Medical geology and its relevance in Africa. S Afr J Sci 116(5–6). http://dx.doi. org/10.17159/sajs.2020/7699 Mouri H (2020b) Interview by ISET careers SA magazine. https://www.uj.ac.za/newandevents/ Pages/Career-Profile-Prof-Hassina-Mouri.aspx Munyangane* P, Mouri H, Kramers J (2017) Assessment of some potential harmful trace elements (PHTEs) in the borehole water of Greater Giyani, Limpopo Province, South Africa: possible implications for human health. Environ Geochem Health 39(5):1201–1219 Munyangane* P, Mouri H, Kramers J (2018) Toxic trace constituents in drinking borehole water of rural Greater Giyani area South Africa. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov.5–7, 2018, Johannesburg, South Africa Sanyaolu* M, Hassina M, Odukoya A (2017) Iodine and the prevalence of endemic goiter in Nigeria—a case study from Ajara—Badagry in Lagos, South-Western Nigeria. In: Seventh International Conference on Medical Geology. Conference Materials, Russia/Publishing House of I.M. Sechenov First MSMU, M. SD-55, 87 Sanyaolu* M, Hassina M, Odukoya A, Selinus O (2018a) A possible geogenic cause of goiter occurrence in the coastal environment of SW Nigeria: a case study from Badagry, Lagos. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, vol 20, p 1151 Sanyaolu* OM, Odukoya A, Selinus O, Hassina M (2018b) Possible cause of goiter in SW Nigeria: Badagry, Lagos case study. In: Geocongress 2018 Abstract book, vol 123, p 224 Sanyaolu* M, Mouri H, Odukoya A, Selinus O. (2018c) Possible causes of goiter occurrences in Badagry, Lagos, SW Nigeria: iodine and other trace elements in drinking water. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov.5–7, 2018 Sanyaolu*  M, Mouri H, Selinus O (2020a) Geochemical and health risk assessment of drinking water in Badagry, Lagos southwest Nigeria: possible contribution to thyroid dysfunction. J Environ Geochem Health (Under review) Sanyaolu* OM, Candeias C, Gbadebo A, Dowling K, Mouri H (2020b) Assessment of uranium and thorium concentrations in rocks and waters around a quarry in Ogun State, Southwestern Nigeria: evaluation of a potential health hazards. In: 3rd Conference of the Arabian Journal of Geosciences (CAJG). Virtual presentation on 3rd November 2020, ID 1048, p 69

27  Medical Geology in Africa: An Example of a Successful Educational and Research… 881 Sanyaolu* OM, Candeias C, Gbadebo A, Mouri H (2020c) Impact of quarry activities on human health and environment: the case study of Ogun state, Southwest Nigeria. In: 36 International geological congress (IGC) 2020, Delhi NCR, India Sanyaolu*  M, Mouri H, Odukoya A, Selinus O. (2021) Source, pathway and health effects of iodine in the natural environment. In: Selinus O, Siegel M, Finkelman R (eds) Practical applications of Medical Geology. (This book) Shelembe * R, Mouri H, Kramers JD, Selinus O (2012) The Pilanesberg Alkaline Complex and the Rustenburg Layered Suite: possible sources of contamination of groundwater and health impact on North West Province communities, South Africa. IGC 33, Brisbane, Aug. 2012 Shelembe * R, Mouri H, Kramers JD, Selinus O (2016) Health impacts of the Pilanesberg Complex and the Rustenburg Layered Suite on communities in the Mabeskraal-Mabaalstad areas in the North West Province. IGC 34, Cape Town, South Africa, Aug. 2016 Sihlahla* M, Mouri H, Nomngongo NP (2018a) Assessment of bioavailability and mobility of potential toxic elements in agricultural soils. EGU General Assembly 2018, Vienna, Austria. In: EGU General Assembly Conference Abstracts, vol 20, p 16006 Sihlahla* M, Mouri H, Nomngongo PN (2018b) Uptake of heavy metals by vegetable plants grown on potentially contaminated agricultural soils: evaluating heavy metal accumulation and potential health risk. In: Second International Symposium: Medical Geology in Africa (ISMGAf-2), Nov.5–7, 2018, Johannesburg, South Africa Sihlahla* M, Mouri H, Nomngongo NP (2019) Uptake of trace elements by vegetable plants grown on agricultural soils: evaluation of trace metal accumulation and potential health risk. J Afr Earth Sci 160(103):635 Sihlahla * M, Mouri H, Nomngongo PN (2020) Assessment of bioavailability and mobility of major and trace elements in agricultural soils collected in Port St Johns, Eastern Cape, South Africa using single extraction procedures and pseudo-total digestion. J Environ Health Sci Eng. https://doi.org/10.1007/s40201-020-00581-x United Nations General Assembly (2015) Draft outcome document of the United Nations summit for the adoption of the post-2015 development agenda. https://digitallibrary.un.org/ record/800852?ln=en World Health Organisation (WHO) (2018) The state of health in the WHO African Region: an analysis of the status of health, health services and health systems in the context of the sustainable development goals. WHO Regional Office for Africa, Brazzaville. Licence: CC BY-NC-SA 3.0 IGO

Chapter 28

Medical Geology Outreach: A Major Success Story from Turkey Alper Baba and Robert B. Finkelman

Abstract  It is incumbent upon medical geology practitioners to reach out to students, science faculties, decision makers, and the biomedical/public health communities to promote this emerging discipline. Perhaps the most successful of these efforts have taken place in Turkey where medical geology courses have been offered in four medical and ten engineering faculties. As a result of these outreach efforts by the Turkish medical geology community for the past decade, there has been robust interactions with scientists from many disciplines and collaborative research on groundwater quality, asbestos, radon, arsenic, mesothelioma, fluorosis, etc. Keywords  Medical geology · Education · Human health · Turkey

28.1  Introduction Environmental health issues are global in their reach, effecting people in every country in the world to varying degrees. The discipline that studies the subset of these issues that are caused by geologic materials and geologic processes is called Medical Geology. Medical geologists play an important role in identifying potential hazards due to exposure to trace elements, minerals, radioactivity, etc., mobilized often by natural disasters such as earthquakes, tsunamis, landslides, and floods. It is a relatively new discipline having been formally organized only about a dozen years ago (Selinus et al. 2019). In the intervening years, several countries have recognized the importance of this subject and have marshalled efforts to address their medical geology issues. Few countries, if any, have been more successful in this effort than Turkey.

A. Baba (*) Department of International Water Resources, Engineering Faculty, İzmir Institute of Technology, İzmir, Turkey e-mail: [email protected] R. B. Finkelman Department of Geosciences, The University of Texas at Dallas, Richardson, TX, USA e-mail: [email protected] © Springer Nature Switzerland AG 2021 M. Siegel et al. (eds.), Practical Applications of Medical Geology, https://doi.org/10.1007/978-3-030-53893-4_28

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This chapter focuses on the wide range of activities in Turkey that have galvanized scientists from many disciplines and from many sectors to address Turkey’s medical geology issues in what amount to a formula for success. Before we describe the outreach efforts, we will briefly describe some of the medical geology problems in Turkey that may benefit from the outreach efforts.

28.2  Examples of Medical Geology Problems in Turkey 28.2.1  Environmental Cancers Asbestos, silica, arsenic, and radon are among the most common environmental carcinogens. All are considered proven causes of human cancer by IARC (El Ghissassi et al. 2009; Straif et al. 2009). Malignant mesothelioma resulting from environmental exposure to asbestos is a relatively common pleural cancer in southeast and central of Turkey (Tanrikulu et al. 2006). Very few studies have investigated the incidence and risk of malignant mesothelioma associated with distinct sources of asbestos exposure, especially exposure to naturally occurring asbestos (Abakay et al. 2016; Emri et al. 2002). Current biological mechanisms of cancer suggest that all cancers originate from both the environment and genetics, meaning that multiple external factors combined with internal genetic changes could lead to human cancers. This fully supports an effort to prevent carcinogenic exposures (Altundağ 2017). Different measures are used to prevent unacceptable carcinogenic exposure from different sources such as geogenic sources in the external environment. Successful examples include reductions in lung cancer and mesothelioma following bans on asbestos (Christiani 2011). Lung cancer is the most common cancer in the world with 1.8 million new cases reported in 2012 and it is the leading cause of deaths in men (Yılmaz 2017). According to the cancer statistics of 2015, it is estimated that 97,830 men and 69,633 women had cancer in Turkey (Minister of Health 2018), and they spent 2.3 billion euros per year for treatment. Research shows that the incidence of cancer in Turkey increases every year (Yılmaz et al. 2011). Seventy-­ five percent of the cancers will be observed in developing or underdeveloped countries (Thun et  al. 2010). The “Turkey Asbestos Control Strategic Plan, 2014” prepared by a working group including the Turkey Ministry of Health Public Health Agency (Metintaş et al. 2014) concluded that the geological environment is one of the most important factors causing cancer. This project estimated that 15,450 mesothelioma, 5737 lung cancer, 82,290 pleural plaque, 59,431 diffuse pleural fibrosis, and 2286 asbestosis cases will emerge in the population exposed to asbestos for a substantial period of time in rural areas in Turkey. Among the populations with continuing asbestos exposure in rural areas, the number of malignant mesothelioma cases between 2013 and 2033 was estimated as 2511 (Metintaş et  al. 2017). Furthermore, it was estimated that 2511 mesothelioma, 1322 lung cancer, 17,344 pleural plaque, 12,526 diffuse pleural fibrosis, and 482 asbestosis cases will emerge

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in the population that continues to be exposed to asbestos between 2013 and 2033 (Metintaş et al. 2014). The Global Burden of Disease projection for the malignant mesothelioma incidence in Turkey was reported as 1.06 per 100,000 people among males, and 0.39 per 100,000 people among females (IHME 2015). On the other hand, local findings reported from the rural areas modestly indicate an underestimation of the impact of the problem (Metintaş et al. 2017). In a cohort composed of villagers who have certainly been exposed to environmental asbestos, the average annual mesothelioma incidence rate was determined as 114.8/100,000 person-years for men, and 159.8/100,000 person-years for women (Metintas et al. 2002).

28.2.2  Arsenic Exposure Turkey is an area of complex geology with active tectonics and high geothermal potential (Fig. 28.1). This natural setting serves as a suitable environment for the occurrence of high levels of toxic elements in soil and water resources (Baba and Ármannsson 2006; Bundschuh et  al. 2010; Layton et  al. 1981; Tamasi and Cini 2004; Yolcubal 2017; Webster and Nordstrom 2003). The high concentration of arsenic in water resources can be attributed to arsenic seeping from fault systems, recent volcanism, and hydrothermally altered systems in different regions of Turkey. Arsenic levels as high as 4% are observed in mineral deposits particularly in

Fig. 28.1  Tectonic map of the eastern Mediterranean region showing structures developed during the Miocene to Holocene time and the distribution of geothermal areas around Turkey (compiled from; Şimsek et al. 2002 and Yigitbas et al. 2004). (SBT Southern Black Sea Thrust, NAFZ North Anatolian Fault Zone, NEAFZ Northeast Anatolian Fault Zone, EAFZ Eastern Anatolian Fault Zone, WAGS Western Anatolian Graben System, DSF Dead Sea Fault Zone, BZS Bitlis-Zagros Suture) (Baba and Ármannsson 2006)

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western Turkey. In addition, arsenic in this region is mostly related to argillic alterations of realgar (AsS/As4S4), orpiment (As2S3), and arsenopyrite (FeAsS) minerals in volcanic formations (Nath et al. 2008). The weathering of arsenic-bearing sulfides existing along the mineralized fault zone in Anatolia is considered to be the main source of arsenic in groundwater and geothermal fluids (Fig. 28.2). The variation in the inflow of As-contaminated waters was possibly caused by variations in the pathways of deep geothermal fluids along the faults crossing the mineralized region. The concentration of arsenic in groundwater and geothermal fluids ranges from 0.01 to 9.3 ppm and from 0.01 to 6 ppm, respectively (Baba 2017a). Due to the geological characteristics of Turkey, there is a rapid increase high arsenic in groundwater resources where use for drinking in the settlements. Especially this problem can be found in the Western Anatolia. For example, Doğan et al. (2005) found high arsenic levels and skin lesions in the Emet (Kütahya) region. A public health survey was conducted in the Simav Region where autopsy reports and official death records were used to investigate the causes of death (Gunduz et al. 2015). The arsenic levels in the local groundwater ranged from 99 μg/L to 561 μg/L (exceeding the guideline value of 10 μg/L) in the Simav region where 402 deaths were reported with cardiovascular system diseases (44%) and cancers (15%), as the major causes. Cancers of the lung (44%), prostate (10%), colon (10%), and gastric (8%) were comparably higher in villages with high arsenic levels in drinking water resources (Gunduz et al. 2015). High levels of arsenic and aluminum were found in some groundwater resources from hydrothermally altered rocks in different parts of Turkey. In the Biga Peninsula, a public health survey had been conducted on locals who are exposed to high aluminum containing water originating from deeply altered volcanic rocks. In this study, a total of 273 people residing on the Biga Peninsula 18 years and older were selected as the research group (Fig. 28.3). The results showed that neuropathy histories were significantly higher in some parts of the region (Baba and Gunduz 2017; Baba 2017b). A large number of public fountains, which are commonly used by the public for drinking and domestic use (especially in rural areas), with low pH, high arsenic, and high iron concentrations are another source of arsenic exposure. In addition, Turkey has many geothermal areas with highly mineralized water (Şimsek

Fig. 28.2  High alteration zones in Anatolia characterized by high concentration of heavy metals such as arsenic

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Fig. 28.3  A public health survey conducted on local population in the Biga Peninsula who are exposed to high aluminum in drinking water

2009, 2017). The low-temperature geothermal fluids have been used as drinking water in some rural regions, which can present a serious public health issues (Baba 2017a).

28.2.3  Fluorosis The World Health Organization (WHO) noted the occurrence of endemic fluorosis in 25 countries including Turkey. Studies on fluorosis in Turkey started in 1955 (Oruç 2017). Endemic dental fluorosis has been identified in Isparta City about 60 years ago (Oruç 2017). Due to elevated fluoride (2–6 ppm) in drinking water, adverse cardiologic effects have also been reported in this region. The source of fluoride in the drinking waters is mostly attributed to weathering or leaching of pyroxene, hornblende, biotite, and fluorapatite minerals in volcanic rocks. Dental and skeletal fluorosis was also observed in the inhabitants of Kizilcaoren Village of Beylikova Town in Eskişehir Province about 30 years ago, where the fluoride content of the drinking water ranged from 3.9 to 5.0  ppm (Oruç 2017). In addition, dental fluorosis was identified in primary school students (in children between 7 and 13 years of age) in the rural settlements of Sarım and Karataş located in the northwest of Şanlıurfa (Derin et  al. 2017) (Fig.  28.4). The fluoride concentrations in water in these regions are as high as 4 mg/L (Atasoy and Yesilnacar 2017).

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Fig. 28.4  An example of dental fluorosis in the Southeast of Turkey (photo from Dr. İrfan Yesilnacar)

28.2.4  Asbestos and Erionite Exposure Fibrous minerals such as asbestos and zeolites present a health hazard in many regions in Turkey. Turkey, among many countries with large asbestos reserves globally, has the highest prevalence of endemic pulmonary diseases related to asbestos (Karakoca et  al. 1997; Yiğitbaş et  al. 2015). Asbestos deposits have been used locally by the rural inhabitants of Central and Southeastern Anatolia for domestic purposes for many years. Mineralogical analysis revealed that tremolite is the most prominent asbestos type found in the region. It has been demonstrated that both asbestos and erionite cause a variety of benign and malignant chest diseases (Emri et al. 2002). For example, asbestos-related diseases (asbestosis and mesothelioma) have been detected in many villages associated with the cities of Çanakkale, Eskişehir, Muğla, Yozgat, Sivas, Diyarbakir, Elazığ, Malatya, Adıyaman, Urfa, Denizli, Burdur, Kütahya, Afyon, and Hatay. Soils contaminated with asbestos are used by the villagers to produce plaster and white paint used in their houses (Fig.  28.5). The diseases related to asbestos exposure have a high frequency of occurrence in the areas where this exposure occurs. By 2015, asbestos exposure has been found in 379 villages in rural areas of Turkey with over 158,069 people determined to be exposed (Metintaş et al. 2017). In this population, predicted incidents of lung cancer and mesothelioma may reach 25,000 during next 20 years (Metintaş 2017). Erionite, a zeolite mineral whose structure is similar to asbestos, was determined to be a powerful carcinogen (Metintaş et al. 2010). The risk of mesothelioma due to erionite exposure in three villages of Cappadocia is the highest incidence in the world. The risk was 298/100,000 person-years for men and 401/100,000 person-­ years for women. Compared to the world, these values are 229 times higher for men and 2005 times higher for women. In these villages, mesothelioma-related deaths constitute more than 50% of all deaths (Metintaş 2017; Metintaş et al. 2017).

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Fig. 28.5  Soils contaminated with asbestos are used by the villagers in Cappadocia region

28.2.5  Benefits of Clay Materials The use of clay by humans for therapeutic, wellness, and cosmetic purposes is known from ancient times in Anatolia (Sholt and Gavron 2006; Çelik et al. 2016). Clays are commonly used for pharmaceutical (treatment) purposes, due to their high surface area, appropriate rheological properties, and good ion exchange capacity. However, clays traditionally used for therapeutic, wellness, or skin care may pose some significant risks to health such as anemia and parasites (Çelik and Karakaya 2017).

28.3  Medical Geology Outreach in Turkey Today interest in medical geology is growing and presents the geoscientist with huge opportunities for collaborative work with the medical community and other disciplines. This cooperation has great potential to help understand, mitigate, and possibly eradicate environmental health problems that have plagued humans for thousands of years. Turkey has many varied and interesting medical geologic problems, as well as being rich in natural geological, hydrogeological, and tectonic properties. Mainly these problems are contamination of water resources, natural radioactivity, mineral dust, acid rock/mine drainage. In Turkey, the concept of “Medical Geology” was not understood sufficiently and there are no legal regulations dealing with environmental health issues except for the dust diseases such as asbestosis and silicosis although many problems associated with the geological environment exist (Arık 2017). Medical geology practitioners in Turkey have

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managed to reach out to students, science faculties, decision makers, and the biomedical/public health communities to promote this emerging discipline. Perhaps the most successful of these efforts have been the creation of medical geology courses in four medical and ten engineering faculties in Turkey. Medical geology courses have been offered in four medical schools belonging to the state universities (Canakkale Onsekiz Mart University, Cumhuriyet University, Harran University and Selçuk University). Three graduate and nine undergraduate medical geology courses are being offered in the Geological Engineering Department of Akdeniz University, Canakkale Onsekiz Mart University, Dokuz Eylul University, İstanbul Technical University, İstanbul University, Middle East Technical University, Niğde University, Osmangazi University and Selçuk University. In addition, one undergraduate medical geology course is being offered in the Environmental Engineering Department of Harran University. Apart from these, a Mesothelioma and Medical Geology Research and Application Center was opened at Hacettepe University. The Turkish Chamber of Geological Engineers has a special chapter on medical geology. This Chamber has been organizing various scientific activities such as panels, workshops, and symposia on medical geology (Fig. 28.6). The first medical geology workshop was held in 2009 in the Cappadocia Region and the second workshop was held in 2013 in Antalya. Furthermore, the first medical geology symposium was

Fig. 28.6  Medical geology workshop organized by the Turkish Chamber of Geological Engineers in 2017. This workshop was attended by 10 oncologists, 5 public health researchers, and 15 geoscientists

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held in 2005  in Ankara and the second symposium was held in 2015  in Konya (Fig.  28.7). In addition, the Geological Congress of Turkey, a long-­established, highly respected scientific event for earth sciences in Turkey, held their 71st conference in Ankara in April 2018 (Fig.  28.8). The main theme of the conference was “Geology and Health”. Special sessions and panels were organized on Medical Geology. The importance of Medical Geology has been recognized in Turkey in recent years and this interdisciplinary research area has begun to rapidly develop.

28.4  Conclusions As a result of the outreach efforts by the Turkish medical geology community, there has been a robust interaction between scientists from many disciplines and initiation of collaborative research on groundwater quality, asbestos, radon, arsenic,

Fig. 28.7  Medical geology symposia and workshops in Turkey organized between 2009 and 2015

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Fig. 28.8  The main theme of the 71st Geological Congress of Turkey was “Geology and Health”

mesothelioma, fluorosis, etc. Clearly, these outreach efforts have demonstrated that medical geology studies are important to Turkey and that the outreach example demonstrated by the Turkish medical geology community should be emulated elsewhere.

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Baba A (2017a) Water quality and its effect on human health. In: 71st Geological Congress of Turkey, April 2018c, Ankara, p 8 Baba A (2017b) Arsenic in water resources in Turkey and its effects on human health. In: 71st Geological Congress of Turkey, April 2018d, Ankara, p 948 Baba A, Ármannsson H (2006) Environmental impact of the utilization of a geothermal area in Turkey. Energy Source 1:267–278 Baba A, Gunduz O (2017) Effect of geogenic factors on water quality and its relation to human health around Mount Ida, Turkey. Water 9:66. https://doi.org/10.3390/w9010066 Bundschuh J, Bhattacharya P, Hoinkis J, Kabay N, Jean J-S, Litter MI (2010) Groundwater arsenic: from genesis to sustainable remediation. Water Res 44:5511 Çelik KM, Karakaya N (2017) Certification and quality criteria of Peloids used for therapeutic and cosmetic purposes and basic concepts, benefits and risks. In: 71st Geological Congress of Turkey, April 2018e, Ankara, p 960 Çelik KM, Karakaya N, Cingilli VH (2016) Thermal properties of some Turkish peloids and clay minerals for their use in pelotherapy. Geomaterials 6:79–90 Christiani DC (2011) Combating environmental causes of cancer. N Engl J Med 364:791–793 Derin P, Yeşilnacar Mİ, Bayhan İ, Çalışır M, Kirmit A (2017) Investigation of drinking water quality in terms of high fluoride level in a rural area: the case of Sarim and Karataş Village (Şanliurfa), first findings. In: 71st Geological Congress of Turkey, April 2018f, Ankara, p 834 Doğan M, Doğan AU, Çelebi C, Barış YI (2005) Geogenic arsenic and a survey of skin lesions in the Emet Region of Kütahya, Turkey. Indoor Built Environ 14:533–536 El Ghissassi F, Baan R, Straif K, Grosse Y, Secretan B, Bouvard V (2009) A review of human carcinogens-part D: radiation. Lancet Oncol 10(8):751–752 Emri S, Demir A, Dogan M, Akay H, Bozkurt B, Carbone M, Baris I (2002) Lung diseases due to environmental exposures to erionite and asbestos in Turkey. Toxicol Lett 127(1–3):251–257 Gunduz O, Bakar Ç, Simsek C, Baba A, Elçi A, Gurleyuk H, Mutlu M, Cakir A (2015) Statistical analysis of death causes (2005–2010) in villages with high arsenic levels in drinking water supplies of Simav plain, Turkey. Arch Environ Occup Health 70:35. https://doi.org/10.108 0/19338244.2013.872076 IHME (2015) The global burden of disease: generating evidence, guiding policy. Institute for Health Metrics and Evaluation, Seattle, WA Karakoca Y, Emri S, Cangir AK, Barıs YI (1997) Environmental pleural plaques due to asbestos and fibrous zeolite exposure in Turkey. Indoor Built Environ 6:100–105 Layton DW, Anspaugh LR, O’Banion KD (1981) Health and environmental effects document on geothermal energy. Health and Environmental Risk Analysis Program, Human Health and Assessment Division, Office of Health and Environmental Research, Office of Energy Research, U.S.  Department of Energy, Lawrence Livermore Laboratory, University of California, Livermore, CA, pp 1–69 Metintaş M (2017) Geological environment and health relationship; Asbestos exposure-­ mesothelioma. In: 71st Geological Congress of Turkey, April 2018g, Ankara, p 4 Metintas S, Metintas M, Ucgun I, Onder U (2002) Malignant mesothelioma due to environmental exposure to asbestos. Chest 122:2224–2229 Metintaş M, Hillerdal G, Metintas S, Dumortier P (2010) Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors. Arch Environ Occup Health 65:86–93 Metintaş M, Batırel HF, Gultekin M, İlter H, Hacıkamiloğlu E, Şen N et  al (2014) Turkey Asbestos Control Strategic Plan Final Report, 24 September 2012–30 December 2014. Turk Thorac J:1–26 Metintaş S, Batırel HF, Bayram H, Yılmaz Ü, Karadağ M, Ak G, Metintaş M (2017) Turkey National Mesothelioma Surveillance and environmental Asbestos exposure control program. Int J Environ Res Public Health 14(11). https://doi.org/10.3390/ijerph14111293 Minister of Health (2018) Cancer statistics of Turkey in 2015. Turkish Minister of Health, Ankara. https://hsgm.saglik.gov.tr/tr/kanser-anasayfa.html

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Nath B, Jean J-S, Lee M-K, Yang H-J, Liu C-C (2008) Geochemistry of high arsenic groundwater in Chia-Nan plain, Southwestern Taiwan: possible sources and reactive transport of arsenic. J Contam Hydrol 99:85–96 Oruç N (2017) Fluoride toxication in water resources of Turkey. In: 71st Geological Congress of Turkey, April 2018h, Ankara, p 950 Selinus O, Finkelman RB, Centeno JA (2019) A recent history of medical geology. Acta Geochim 39:155–159 Sholt M, Gavron T (2006) Therapeutic qualities of clay-work in art therapy and psychotherapy: a review. Art Ther 23(2):66–72 Şimsek S (2009) Geothermal energy development possibilities in Turkey. In: NUMOW Conference on geothermal energy in Turkey, October, 2009 Potsdam-Germany, pp 1–6 Şimşek C (2017) Natural environment and human. In: 71st Geological Congress of Turkey, April 2018, Ankara, p 910 Şimsek S, Yildirim N, Simsek ZN, Karakus H (2002) Changes in geothermal resources at earthquake regions and their importance. Proceedings of Middle Anatolian Geothermal Energy and Environmental Symposium, pp 1–13 Straif K, Benbrahim-Tallaa L, Baan R, Grosse Y, Secretan B, El Ghissassi F (2009) A review of human carcinogens—part C: metals, arsenic, dusts, and fibres. Lancet Oncol 10(5):453–454 Tamasi G, Cini R (2004) Heavy metals in drinking waters from mount Amiata (Tuscany, Italy). Possible risks from arsenic for public health in the province of Siena. Sci Total Environ 327:41–51 Tanrikulu AC, Senyigit A, Dagli CE, Babayigit C, Abakay A (2006) Environmental malignant pleural mesothelioma in Southeast Turkey. Saudi Med J 27:1605–1607 Thun MJ, De Lancey JO, Center MM, Jemal A, Ward EM (2010) The global burden of cancer: priorities for prevention. Carcinogenesis 31(1):100–110 Webster JG, Nordstrom DG (2003) Geothermal arsenic. In: Welch AH, Stollenwerk KG (eds) Arsenic in ground water: geochemistry and occurrence. Springer, New York, pp 101–125 Yigitbas E, Elmas A, Sefunc A, Ozer N (2004) Major neotectonic features of eastern Marmara region, Turkey: development of the Adapazari-Karasu corridor and its tectonic significance. Geol J 39(2):179–198 Yiğitbaş E, Mirici A, Gönlügür U, Bakar C, Tunç O, Şengün F, Işıkoğlu Ö (2015) Evaluation of Asbestos exposure in Dumanli Village (Çanakkale-Turkey) from a medical geology viewpoint: an inter-disciplinary study. Bull Min Res Exp 151:247–258 Yılmaz Ü (2017) The natural environment and cancer of the respiratory system. In: 71st geological congress of Turkey, April 2018i, Ankara, p 904 Yılmaz HH, Yazıhan N, Tunca D, Sevinç A, Olcay EÖ, Özgül N, Tuncer M (2011) Cancer trends and incidence and mortality patterns in Turkey. Jpn J Clin Oncol 41(1):10–16 Yolcubal İ (2017) Heavy metals in environment: sources, occurrence and fate. In: 71st Geological Congress of Turkey, April 2018j, Ankara, p 952

Glossary

A-axis A vector direction defined by the space group and crystal structure for a particular crystalline form—a term used in crystallography. Absorption   The process by which a substance or a xenobiotic is brought into a body (human or animal) or incorporated into the structure of a mineral. Acid rain   Contamination of rain by artificial pollutants or natural emissions (such as sulfur dioxide from volcanic activity) which produces an acid composition. Acute myocardial infarction (AMI)  Gross necrosis of the heart muscle as a result of interruption of the blood supply to the area. Adsorption   The binding of a chemical compound to a solid surface. Advection   A transport process in which dissolved chemicals move with flowing groundwater. Albedo     The percentage of the incoming solar radiation reflected back by different parts of the Earth’s surface. Alkali disease     Disease affecting animals that ingest feed with a high selenium concentration, characterized by dullness, lack of vitality, emaciation, rough coat, sloughing of the hooves, erosion of the joints and bones, anemia, lameness, liver cirrhosis, and reduced reproductive performance. Alkalinity   The capacity of solutes in a solution to react with and neutralize acid determined by titration with a strong acid to an end point at which virtually all solutes contributing to the alkalinity have reacted. In general the alkalinity in water equates with the bicarbonate concentration. Allergy  Immunologic state induced in a susceptible subject by an antigen (allergen). Alluvial   Deposited by rivers. Alteration (Earth science)  A process due to high-temperature fluids and gases that occurs within the Earth’s crust and results in the formation of new mineral suites that are in equilibrium with their environment. Alteration can also occur at low temperatures.

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Glossary

Aluminosilicate  A mineral composed dominantly of aluminum, silicon, and oxygen, and lesser amounts of cations such as sodium, potassium, calcium, magnesium, and iron. Amorphous  A lack of crystallinity or the regular extended three-dimensional order of the atoms in a solid. Anaerobic/aerobic  Environmental conditions in which oxygen is absent/present. Analyte   Any substance whose identity or concentration is being determined. Anemia  Any of several conditions in which the oxygen carrying capacity of the blood is below normal due to reductions in the number of red blood cells (hypocytic) and/or the amount of hemoglobin per red blood cell (hypochromic). Aneuploidy   Cellular state where there is an abnormal number of chromosomes, not a multiple of the haploid number of chromosomes. Aneurysm  Localized ballooning of the aorta or an artery, potentially causing pressure on adjacent structures and liability to rupture. Angiotensin   A vasoconstrictive hormone. Aqueous speciation   The partitioning of chemical components between various aqueous species in a solution: free species (e.g., Ca2+), ion pairs (e.g., CaCO30), and complexes (e.g., Fe(CN)63). Aquifer   A water-bearing rock formation. Aquitard  A rock formation with poor permeability and hence a poor water-­ bearing unit. Arrhythmia   Irregularity of the heartbeat. Arthroconidia   Fungal spores released by fragmentation or separation of the cells of a hypha. Asbestos  A commonly used term for a group of fibrous silicate minerals that includes extremely fibrous serpentine (chrysotile) and the amphibole minerals crocidolite, amosite, tremolite, actinolite, and anthophyllite. Asbestosis   Degenerative fibrosis of the lung resulting from chronic inhalation of asbestos fibers. Ash   Fine particles of pulverized rock ejected from volcanoes. Asphyxiant   Gas which produces suffocation by replacing oxygen in the respiratory system. Ataxia   Lack of coordination of muscle for voluntary movement. Autosome   A chromosome not involved in sex determination. The diploid human genome consists of 46 chromosomes, 22 pairs of autosomes, and 1 pair of sex chromosomes (the X and Y chromosomes). Background   The property, as applied to a location or measurements from such locations, of being due to natural processes alone and unaffected by anthropogenic processes. In some instances the term natural background is used to reinforce the non-anthropogenic aspect. With the global atmospheric transport of anthropogenic contaminants, e.g., persistent organic pollutants (POPs), it is a moot point whether background sites exist for some substances. Basal cell carcinoma   Slow growing, locally invasive neoplasm derived from basal cells of epidermis or hair follicles.

Glossary

897

Baseline   A measure of the natural background or ambient level of an element/substance. Some people also suggest that baseline is the current background which could include natural and anthropogenic components. Basophilic degeneration  Pathologic change in tissue noted by blue staining of connective tissue with hematoxylin-eosin stain. Benign  Usual or normal—the opposite of cancerous when applied to cells or tumors. Bioaccumulation   Process by which an element is taken into an organism, possibly transformed into another chemical species, and retained so that the element’s concentration in the biota is greater than its concentration in the media in which the biota is sustained. Bioavailability   The property of a substance that makes its chemical uptake by biota possible. Bioessential/bioessentiality     Present in sufficient amounts to support essential biochemical processes imperative for sustaining life. Biosphere   The sum of all organisms on Earth. Bombs   (Volcanic) clots of lava that are ejected in a molten or semi-molten state and congeal before striking the ground. Buffer   A chemical compound that controls pH by binding to hydrogen ions. Bulk analysis   Chemical analysis of an entire body/substance of rock or soil or a subpart with little or no segregation of specific areas or components. Calcitonin   Hormone secreted by the thyroid gland important in the homeostatic regulation of serum calcium levels. Carbon dioxide   A colorless odorless gas and high concentrations of CO2 act as an inert asphyxiant in humans. Carbonatite   An igneous rock composed of carbonate minerals. Carcinogen  A substance that can directly or indirectly cause a cell to become malignant. Carcinogenesis   The mechanism by which cancer is caused. Cardiomyopathy   Disease of the heart muscle (myocardium). Cardiovascular disease (CVD)   Disease pertaining to the heart and blood vessels, including, for example, both AMI and cerebrovascular disease (stroke). Cation exchange capacity (CEC)   The ability of a soil or soil constituent (e.g., clay mineral or humus) to adsorb cations on permanent, or pH-dependent, negatively charged sites on surfaces. Cations of different elements can replace each other as counter ions to the negative charges. Chelate   The complex formed through the bonding of a metal ion with two or more polar groupings within a single molecule. Chromatography   The separation of a mixture of compounds using solid, liquid, or gas phases based on affinity of molecules for the phase. Chromosome aberrations  Any deviation from the normal number or morphology of chromosomes. Clay minerals   Phyllosilicate minerals with a small grain size, commonly 70% SiO2) with high concentrations of sodium and potassium. Granitization  A metamorphic process by which sedimentary and metamorphic rocks with a chemistry similar to granites (granitoids) are transformed mineralogically into rocks that look like the granites formed by igneous intrusive processes. Groundwater  Subsurface water in the zone of saturation in which all pore spaces are filled with liquid water (although sometimes the term ­groundwater is used inclusively for all water below the land surface, to distinguish it from surface water). Half-life   The time in which one-half of the atoms of a particular radioactive substance decays to another nuclear form. Hardness water   The content of metallic ions in water, predominantly calcium and magnesium, which react with sodium soaps to produce solid soaps or scummy residue and which react with negative ions to produce scale when heated in boilers.

Glossary

901

Heavy metal   A metal with a density more than 4500 kgm3. Heme     The protoporhyrin component of hemoglobin (in erythrocytes) and myoglobin (in myocytes), the proteinaceous chelation complexes with iron that facilitate transport and binding of molecular oxygen to and in cells. Hemolysis   Lysis of erythrocytes that potentially causes anemia. Herbivores  Animals normally feeding on plant material such as cattle, horses, sheep, antelope, deer, and elephants, but also rodents like mice, rabbits, and hares. As vertebrates lack enzymes in the gastrointestinal tract that can digest cellulose and other complex carbohydrates present in plants, they utilize microorganisms living in their gastrointestinal tract for this process. See also Ruminants and Large Intestine Fermenters. Hormone   A circulating molecule released by one type of cell or organ to control the activity of another over the long term, e.g., thyroxine. Humus   The fraction of the soil organic matter produced by secondary synthesis through the action of soil microorganisms. It comprises a series of moderately high molecular weight compounds that have a high adsorptive capacity for many metal ions. Hyperkeratosis   Hyperplasia of the stratum corneum (specific layer in epidermis/ skin), the outermost layer in the epidermis. Hypoxia   Less than the physiologically normal amount of oxygen in organs/tissues. Idiopathic  Describing a disease of unknown cause. Igneous rocks   Formed from the cooling and solidification of molten rock originating from below the Earth’s surface, includes volcanic rocks. Incidence   Quantifies the number of new cases/events that develop in a population at risk during a specified time interval. Inductively coupled plasma (ICP)  An argon plasma with a temperature of approximately 7000–10,000 K, produced by coupling inductively electrical power to an Ar stream with a high-frequency generator (transmitter). Then plasma is used as an emission source (atomic emission spectrometry) or as an ionization source (mass spectrometry). Isotope   One of two or more atoms with the same atomic number but with different atomic weights. Keratinocytes   Cells of the epidermis that produce the protein keratin. Keshan disease   An endemic cardiomyopathy (heart disease) that mainly affects children and women of childbearing age in China. Leachate  A liquid that carries dissolved compounds from a material through which it has percolated (e.g., water which carries adsorbed elements from settled volcanic ash into soil or water). Limestone   A sedimentary rock composed of calcium carbonate. lOAEL  The lowest dose at which adverse effects are observed to occur in an experimental setting. Macronutrient   General term for dietary essential nutrients required in relatively large quantities (hundreds of milligrams to multiple grams) per day which include energy (calories), protein, calcium, phosphorus, magnesium, sodium, potassium, and chloride.

902

Glossary

Macrophage   Mononuclear phagocytes (large leukocytes) that travel in the blood and can leave the bloodstream and enter tissues protecting the body by digesting debris and foreign cells. Magma   Any hot mobile material within the Earth that has the capacity to move into or through the crust. Matrix   The basis or collection of materials within which other materials develop. The organic matrix is the base in which mineral materials are deposited to form bone. Mesothelioma   A highly malignant type of cancer, usually arising from the pleura, which is the lining of the thoracic cavity, and characteristically associated with exposure to asbestos. Metadata  Data about data, typically containing information such as time and place of database creation, field and Metalliferous   Rich in metals. Metalloid   An element which behaves partly as a metal and partly as a non-­metal, sometimes referred to as a “semi-metal.” Metamorphic rocks   Rock formed from the alteration of existing rock material due to heat and/or pressure. Micronutrient   General term for dietary essential nutrients required in relatively small amounts (less than multiple milligrams) per day which include the vitamins and trace elements. Mineral   A naturally occurring compound with definite chemical composition and crystal structure, of which there exist over 4000 officially defined species. Mineral elements   Equal to elements. This term is used by nutritionists. Mineralization   The presence of ore and non-ore (gangue) minerals in host rocks, concentrated as veins, or as replacements of existing minerals or disseminated occurrences typically gives rise to rocks with high concentrations of some of the rarer elements. Mitochondrion   Subcellular organelle containing the electron transport chain of cytochromes and the enzymes of the tricarboxylic acid cycle and fatty acid oxidation and oxidative phosphorylation, thus constituting the cell’s primary source of energy. Natural background     A term used to describe the geochemical variability and the range of data values due to natural processes that characterize a particular geological or geochemical occurrence. See also Background and Baseline. Necrosis   Cell death. nOAEL   The highest dose at which no observed adverse effects occur in an experimental setting. Organelle  A compartment found in eukaryotes derived from captured bacteria and with residual independent genes, e.g., mitochondria which create useful energy from oxidation of sugars and chloroplasts which create useful energy from lightgenerating oxygen. Osteoporosis  A generalized term for the loss of bone tissues in bone organs. There are multiple possible causes of osteoporosis and the loss may occur at any age, but it is more prevalent in older individuals. The variations of osteoporosis remain active areas for investigation.

Glossary

903

Oxidation   Chemical process which can lead to the fixation of oxygen or the loss of hydrogen, or the loss of electrons—the opposite of reduction. Phyllosilicate  A group of aluminosilicate minerals that have a sheeted crystal structure which permits cations to be trapped between the sheets and around the sheet edges. Because of these properties some are capable of sequestering geochemically significant amounts of cations, metals. Phytoavailability A specific instance of bioavailability with reference to plants. In some instances it is useful to differentiate between phyto- and bioavailability along the food chain. Phytoavailability controls the transfer of a trace element from soil to a plant, and bioavailability controls the transfer of the trace element from the plant material to the receptor organism; the transfer factors are unlikely to be the same. Phytotoxic   Toxic to plants. Pica   A craving for unnatural articles of food. The name pica comes from the Latin for magpie, a bird that picks up a variety of things either to satisfy hunger or out of curiosity. Geophagy, the deliberate ingestion of soil, is a form of pica. Pleural plaques  A fibrous thickening of the parietal pleura which is characteristically caused by inhalation of the fibers of asbestiform minerals. Pneumoconiosis  A chronic fibrosing lung disease from contact with respirable mineral dusts; examples include silicosis and asbestosis. Podsol   A type of soil which can be found in cool, humid environments on freely drained parent materials usually under coniferous trees or ericaceous vegetation. Typically has an iron pan as a result of leaching. Also called spodosols in the USDA Soil Taxonomy classification. Pyrite iron sulfide (FeS2)  Otherwise known as fool’s gold occurs commonly in zones of ore mineralization and in sediments under strongly reducing conditions. Quaternary  The most recent period of geological time, spanning 0–2  million years before Present divided into the earliest period, the Pleistocene (ending with the last glacial maximum), and the subsequent Holocene (the last 13,000 years). Radionuclide   A radioactive nuclide. Radon   A colorless radioactive element comprises the isotope radon-222, a decay product of radium. 222Rn (radon) is a gas. It occurs in the uranium-238 decay series and provides about 50% of the total radiation dose to the average person. Redox potential (pe or Eh)  pe and Eh are related variables that express a measure of the ratio of the aqueous activity of an oxidized species (an electron acceptor, such as Fe3+) to that of a reduced species (an electron donor, such as Fe2+). The redox potential of a solution can provide a sense of the oxidizing or reducing nature of a solution or aqueous environment (oxic, suboxic, sulfidic, methanic). Redox reactions  Coupled chemical oxidation and reduction reactions involving the exchange of electrons; many elements have changeable redox states in groundwater; the most important redox reactions involve the oxidation or reduction of iron and manganese, introduction or consumption of nitrogen compounds (including nitrate), introduction or consumption of oxygen (including dissolved oxygen), and consumption of organic carbon. Reducing condition   Anaerobic condition, formed where nearly all of the oxygen has been consumed by reactions such as oxidation of organic matter or of sulfide; reducing conditions commonly occur in confined aquifers.

904

Glossary

Regolith  A deposit of physically and/or chemically weathered rock material which has not developed into a soil due to the absence of biological activity and the presence of organic matter. Rhizosphere   The zone around plant roots (2 mm thick) in which there is intense microbial activity due to root exudates and which has chemical properties different from the bulk of the soil. Risk assessment  A systematic way of estimating the probability of an adverse outcome based on the known properties of a hazard such as a chemical. Sarcoidosis   A systemic granulomatous disease of unknown cause. Sarcomatoid   Resembling a sarcoma, a neoplasm of soft tissue. Scanning electron microscope (SEM)   A method employing an electron microscope and a finely focused beam of electrons that is moved across a sample allowing Sedimentary rock  Rock formed by compression of material derived from the weathering or deposition of preexisting rock fragments, marine or other organic debris, or by chemical precipitation. Sesquioxide   Oxide mineral containing three atoms of oxygen and two atoms of another chemical substance. Iron and aluminum oxides are the most important in the natural environment. Shale   A sedimentary rock composed of fine particles, mainly made up of clay. Silicate   A mineral composed dominantly of silicon and oxygen, with or without other elements such as magnesium, iron, calcium, sodium, and potassium. Silicosis    A form of pneumoconiosis produced by inhalation of fine silica particles. Smectite    A group of clay minerals (phyllosilicates) that includes montmorillonite and minerals of similar chemical composition. They possess high cation exchange capacities and are therefore capable of sequestering labile cations. Soil profile (solum)  The vertical section of a soil from the surface to its underlying parent material. It comprises distinct layers (horizons) differing in appearance or texture and chemical properties. The soil profile is the basis of soil classification (soils with characteristic combinations of horizons). Soil texture   The relative proportions of sand (0.05–2 mm), silt (0.002–0.05 mm), and clay (