Environmental Risks Posed by Microplastics in Urban Waterways 981990627X, 9789819906277

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SpringerBriefs in Water Science and Technology Beibei He · An Liu · Godwin Ayoko · Prasanna Egodawatta · Buddhi Wijesiri · Ashantha Goonetilleke

Environmental Risks Posed by Microplastics in Urban Waterways

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Beibei He · An Liu · Godwin Ayoko · Prasanna Egodawatta · Buddhi Wijesiri · Ashantha Goonetilleke

Environmental Risks Posed by Microplastics in Urban Waterways

Beibei He College of Chemistry and Environmental Engineering Shenzhen University Shenzhen, Guangdong Province, China

An Liu College of Chemistry and Environmental Engineering Shenzhen University Shenzhen, Guangdong Province, China

Godwin Ayoko Faculty of Science, School of Chemistry and Physics Queensland University of Technology Brisbane, QLD, Australia

Prasanna Egodawatta Faculty of Engineering, School of Civil and Environmental Engineering Queensland University of Technology Brisbane, QLD, Australia

Buddhi Wijesiri Faculty of Engineering, School of Civil and Environmental Engineering Queensland University of Technology Brisbane, QLD, Australia

Ashantha Goonetilleke Faculty of Engineering, School of Civil and Environmental Engineering Queensland University of Technology Brisbane, QLD, Australia

ISSN 2194-7244 ISSN 2194-7252 (electronic) SpringerBriefs in Water Science and Technology ISBN 978-981-99-0627-7 ISBN 978-981-99-0628-4 (eBook) https://doi.org/10.1007/978-981-99-0628-4 © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 This work is subject to copyright. All rights are solely and exclusively licensed 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 Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

The exponential increase in plastic products over the past decades has resulted in the ubiquitous presence of plastic pollutants in the environment worldwide. In the recent years, the presence of microplastics (MPs), which is classified as having a diameter smaller than 5 mm, in aquatic environments has been recognized as a significant environmental threat due to adverse effects spanning from molecular level, organism health, ecosystem services to human health. Urban waterways are the first places to suffer from MPs pollution from terrestrial environments. Further, urban waterways are identified as a sink for MPs retention, as well as major pathways of MPs from terrestrial areas to the inland aquatic systems and oceans. In this regard, in-depth knowledge on the occurrence, distribution patterns, environmental risks and migration of different MP types in urban waterways is important in terms of risk assessment and mitigation of plastic pollution. The environmental risks that MPs pose are twofold, MPs alone and with associated contaminants. MPs are known as complex environmental pollutants as they contain a wide range of toxic compounds which are used as additives during the plastic manufacturing process. During degradation, these additives can be released from the plastic particles with time and thus pose threats to the surrounding environment. Additionally, the sorption capacity of MPs to existing contaminants in the surrounding environment such as organic chemical compounds, metals and microbes would compound the toxicity imposed on the aquatic environment. Considering the durability and transferability of MPs in the water column and sediments, the aquatic environment and organisms are subjected to the toxicological effects of MPs for many decades. However, due to the complexity of MPs movement behavior and interaction mechanisms with other contaminants in the aquatic environment, knowledge relating to the risks due to MPs presence and migration remains largely unknown. Given the significant environmental risk and current knowledge gaps, this monograph builds an innovative framework which considers the presence and migration pathways in relation to MPs potential risks as a whole. A comprehensive discussion on the abundance of different MP types in water and sediment compartments in

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urban waterways is initially presented. This is followed by presenting the methodology for assessing and quantifying the multiple risks associated with the occurrence and movement behavior of different MP types in urban waterways. The research study presented created new knowledge relating to adverse effects of MPs on sediment quality in urban riverine system based on the interactions between MPs and co-existing contaminants. Innovative outcomes from this research study were further extended to create a 3D modeling framework by combing a hydrodynamic model and particle tracking model to explore different dispersal and transport characteristics of typical MPs in urban waterways to further understand the potential risks associated with this contaminant. This monograph provides an in-depth understanding of the contribution of different sources to different MPs presence in urban waterways, which in turn is expected to contribute to enhance decision-making in relation to plastic pollution mitigation strategies. The risk assessment approach presented can be used by decision-makers to improve risk predication and for the formulation of effective strategies for the management of waste plastics. The model developed is expected to contribute to enhancing the understanding of the behavior of different MP pollutants in aquatic environments, which in turn can provide important knowledge for source tracking and regulating the emission of plastic pollution in order to minimize the environmental risks posed by waste plastics. Shenzhen, China Shenzhen, China Brisbane, Australia Brisbane, Australia Brisbane, Australia Brisbane, Australia

Beibei He An Liu Godwin Ayoko Prasanna Egodawatta Buddhi Wijesiri Ashantha Goonetilleke

Contents

1 Microplastics as Emerging Pollutants in Urban Waterways . . . . . . . . . . 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 MPs as Environmental Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Pollution of Urban Waterways by MPs . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3.1 Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3.2 Morphological Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Comparison of MPs Presence in the Water Column and the Sediment Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.5 Limitations in MPs Quantification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2 Factors Influencing MPs Presence in Urban Waterways . . . . . . . . . . . . . 2.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Influence of Emission Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Terrestrial-Based Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Aquatic-Based Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Atmospheric-Based Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Influence of Environmental Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.1 Hydrodynamic Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Photothermal Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.3 Microorganism Colonisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13 14 16 16 17 18 19 19 20 21 22 22

3 Risk Associated with MPs in Urban Waterways . . . . . . . . . . . . . . . . . . . . 3.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Release of Toxic Additives in MPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.2 Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25 26 28 28 29

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3.3 Interaction with Contaminants Existing in the Environment . . . . . . . . 3.3.1 Chemical Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.2 Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane River Sediments, Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Sampling Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 Study Sites Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2 Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Laboratory Data Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.1 MPs Separation, Identification and Quantification . . . . . . . . . . 4.3.2 Nutrient Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.3 Metals Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Risks Associated with MPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4.1 Abundance of MPs in Brisbane River Sediments . . . . . . . . . . . 4.4.2 Hazard Index Assessment of Different MP Types . . . . . . . . . . 4.4.3 Risks from Nutrients and Metals in Brisbane River Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Risks Associated with MPs Transport and Dispersion . . . . . . . . . . . . . 4.5.1 Modelling Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.2 MP Dispersal and Transport Model Development . . . . . . . . . . 4.5.3 Variability of MPs Migration Behaviour in Brisbane River Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Practical Implications and Recommendations for Further Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Implication of Plastic Pollutants in Urban Waterways . . . . . . . . . . . . . 5.1.1 Tracking Plastic Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.2 Implementation of Waste Plastics Management . . . . . . . . . . . . 5.2 Recommendations for Further Research . . . . . . . . . . . . . . . . . . . . . . . .

31 31 32 33 34 37 39 39 39 40 40 49 52 53 53 53 56 59 60 60 61 63 67 68 71 72 72 73 74

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 1

Microplastics as Emerging Pollutants in Urban Waterways

Abstract Microplastics (MPs) have been classified as any plastic particle with a diameter less than 5 mm. MPs have been identified as a prominent environmental concern due to the fact that they associate with a wide range of toxic contaminants, and also because of their non-degradability and long lifespan. Urban waterways are important natural resources that support human life, economic development, as well as natural ecosystems, which are closely linked with human and aquatic ecosystem well-being. Urban waterways are also the first places to suffer from MPs pollution derived from terrestrial environments. Therefore, it is essential to fully understand the presence and spatial distribution patterns of MPs in urban waterways to further evaluate the hazardous consequences resulting from their presence. This chapter provides a detailed discussion on MPs pollutants in relation to the definition, occurrence, distribution patterns and morphological characteristics to contribute knowledge on MPs pollution in urban waterways, and provides baseline data for further analysis of MPs from a risk assessment perspective. Keywords MPs pollutants · Distribution patterns · Associated contaminants · Environmental risks · Urban waterways

Abbreviations Al As Ca Cd Co Cr Cs Cu DDT DI Water

Aluminium Arsenic Calcium Cadmium Cobalt Chromium Caesium Copper Dichloro-diphenyl-trichloroethane Deionized water

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 B. He et al., Environmental Risks Posed by Microplastics in Urban Waterways, SpringerBriefs in Water Science and Technology, https://doi.org/10.1007/978-981-99-0628-4_1

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DOA DEHA DEP Fe FT-IR HDPE ICP-MS MPs Mg Mn NaCl NaI Ni NOAA PA PAHs PAN PC PCA PCBs PE PET PLA POM PP PS PUR PVC PVDC QA QC Se TC TN TP Zn ZnCl2

1 Microplastics as Emerging Pollutants in Urban Waterways

Di-octyl adipate Di-(2-ethylhexyl) adipate Diethyl phthalates Iron Fourier Transform Infrared High-density polyethylene Inductive Coupled Plasma-Mass Spectroscopy Microplastics Magnesium Manganese Sodium chloride Sodium iodide Nickel National Oceanic and Atmospheric Administration Polyamide Polycyclic Aromatic Hydrocarbons Polyacrylonitrile Polycarbonate Principal Component Analysis Polychlorinated biphenyls Polyethylene Polyethylene terephthalate Polylactic acid Polyoxymethylene Polypropylene Polystyrene Polyurethane Polyvinyl chloride Polyvinyl dichloride Quality assurance Quality control Selenium Total Carbon Total Nitrogen Total Phosphorus Zinc Zinc chloride

1.1 Background Plastics refer to a family of organic polymers including polyamide (PA), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), and

1.2 MPs as Environmental Pollutants

3

polyvinyl chloride (PVC). The use of plastic products has been increasing since the 1940s when plastics began to be mass produced. Due to properties such as lightweight, low-cost and durability, plastic products are extremely popular for a wide variety of applications, ranging from personal goods to industrial products. To meet the functionality and specific purpose of plastic products, chemical additives such as plasticizers, antioxidants, flame retardants, light and heat stabilisers, slip agents, lubricants, and colorants are added during the production process and many of them are toxic. Although such additives improve the functionality of plastic products, the vast majority of plastic products including packaging, agricultural films, and consumer items are designed for single-use disposable applications, and end up as pollutants in both, terrestrial, inland aquatic, and marine environments (Bosker et al. 2017). The plastic waste globally generated reached over 9000 million metric tonnes in 2022 and is expected to soar to more than 15,000 million metric tonnes in the next decade with a considerably low proportion of recycling (Geyer et al. 2017). As a result, the growing consumption and indiscriminate disposal of plastic materials in the natural environment present a considerable challenge to global environmental protection. Microplastics (MPs) have been classified as any plastic particle with a diameter smaller than 5 mm since Thompson et al. (2004) first defined ‘microplastics’ in the marine environment. The presence of MPs pollutants has also been increasingly reported in soils and waterbodies worldwide. Urban waterways are important natural resources that support human life, economic development, as well as natural ecosystems, and closely link with human and aquatic ecosystem well-being. Urban waterways are the first places to suffer from MPs pollution from terrestrial environments due to a range of anthropogenic activities such as agriculture, traffic, commercial activities and industrial production (He et al. 2020a). Urban waterways are also regarded as transport pathways for MPs migration from the location where they have been disposed to other aquatic environments such as lakes and ponds in the downstream regions and the ocean. Hence, an in-depth and comprehensive understanding of the abundance, distribution patterns, and morphological characteristics of MPs in urban waterways provides essential knowledge for source identification and risk evaluation of plastic pollutants.

1.2 MPs as Environmental Pollutants The presence of small plastic debris of diameter ranging from 0.1 to 2 mm in coastal waters was pointed out for the first time in the 1970s (Carpenter et al. 1972). In the following decades, increasing research emerged on the presence of such debris as a pollutant in aquatic ecosystems, and various size-definitions have been proposed by researchers ranging from < 10 mm, < 5 mm, 2–6 mm, < 2 mm, and < 1 mm as illustrated in Fig. 1.1. Although the characterised size has varied among different studies, plastic particles with a diameter smaller than 5 mm are defined as MPs by the National Oceanic and Atmospheric Administration (NOAA) (Barboza and Gimenez

4

1 Microplastics as Emerging Pollutants in Urban Waterways

POM > polystyrene (PS) > PE > PP. Interestingly, according to past studies, the concentrations of microorganisms on different MPs surfaces follow the order of PP > PE > POM (Wu et al. 2017), PS > PVC (Liu et al. 2019), PP > PE (Lagarde et al. 2016), respectively. This indicates that if more MPs particles with lower hazardous scores accumulate, there are more opportunities for microorganism colonisation and biofilm formation. Specially, for those MPs that are deposited in benthic sediments and difficult to be transported by water flow and sediment movement, risk of microbial accumulation would arise. Considering the durability of MP particles, microorganisms colonised MPs would consequently alter the nutrients concentrations in the areas where this situation occurs (He et al. 2020a). The metals present in the Brisbane River sediments were observed to correlate more with MPs hazard index rather than with MPs abundance with a 95% confidence interval as shown in Fig. 4.12. Such correlations between MPs and metals can be attributed to the metallic additives used. It should be noted that for certain metals, -0.4

-0.2

0.0

0.2

0.4

Co Fe

3

0.4

PC2 (23.2%)

Al MPs hazard index

2

Sr

1

Cr As Cd

Se

Ni

Mn

0.2 Zn

Pb

MPs concentration Cu

0

0.0

TP TN

-1

TC

-0.2

-2 -0.4

-3 -4

-2

0

2

PC1 (31.1%) Fig. 4.12 PCA biplot of MPs, nutrients and metals in Brisbane River sediments

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4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane …

their concentrations in different plastic products would vary due to the desirable properties needed at the time of manufacture (Hahladakis et al. 2018). The significant correlation found in this study between the concentrations of measured metals (such as Fe, Mn, Zn and Pb) and MPs in sediments could be the result of the leaching of iron oxide, manganese based, and zinc-containing chemical compounds that are used either as functional additives or fillers in plastic products.

4.5 Risks Associated with MPs Transport and Dispersion 4.5.1 Modelling Approach The dispersal and transport processes of MPs in Brisbane River sediments was simulated using the combined TUFLOW FV and TUFLOW FV PTM models. TUFLOW FV is a system of equations to describe the conservation of fluid mass and volume in an incompressible fluid, under hydrostatic pressure and Boussinesq assumptions based on the use of a Eulerian or mesh-based frame of reference (Jovanovic et al. 2019). TUFLOW FV model was initially employed to construct a 3D hydrodynamic model which included water flow, depth, salinity, temperature and wave and tidal variations of the Brisbane River catchment boundary conditions. TUFLOW FV PTM is a Lagrangian module for solving 3D transport equations for discrete particles (BMT, 2020). It was used as the particle transport model to simulate MPs migration in the Brisbane River. According to the field investigation results (He et al. 2020b), four common MPs types, namely, PE, PP, PA, and PET were selected to simulate the movement of MP particles in the Brisbane River. The parameters of MP particles, including median diameter, sinking velocity and density of each selected MP type were employed in the TUFLOW FV PTM module. Data on MPs’ median diameter was based on previous experimental results (He et al. 2020b). The sinking velocities of the modelled MPs of different sizes were obtained from laboratory experimental data from the study conducted by Waldschläger and Schüttrumpf (2019). Additionally, though the density of a particles can vary considerably due to factors such as degradation and biofilm formation, it is difficult to obtain quantitative evaluations on the degradation level and biofilm formation. Hence, the most commonly identified densities across a range of studies for the selected MP types were used as the baseline density value for each modelled MP type (Hidalgo-Ruz et al. 2012). As the density of PE and PP has been identified at about 900 kg m−3 , which is below the default water density (1000 kg m−3 ) in the model, all MPs density values were converted using Eq. (4.2). ρs = ρ0 (1 + 0.13) where ρs is the density used in the model (kg m−3 ),

(4.2)

4.5 Risks Associated with MPs Transport and Dispersion

61

ρ0 is the most commonly detected density (kg m−3 ) of modelled MP particles (Hidalgo-Ruz et al. (2012). Mathematical models including bed shear stress, particle erosion and resuspension and bed load transport was employed in the TUFLOW FV PTM module in order to simulate migration processes of MPs. Bed shear stress, which is a measure of the friction force acting on a bed of a water body is an essential input parameter for erosion and bedload modelling. The bed shear model parameter was determined as a default value, which considers bed shear stresses induced by both, currents and waves. The deposition behaviour of the simulated MP particles was determined based on their settling velocity. Particle erosion and resuspension were calculated as a mass flux (g m−2 s−1 ) using the specified erosion module for each MP fraction and the computational cell in the model. Soulsby-vanRijn method (Soulsby 1997) was used as an erosion model for the simulation. As a fundamental transferability parameter of particles bed load transport (Soulsby 1997), critical shear stress was applied using the Soulsby method. The bed concentrations of MP particles at each computational cell were calculated based on the TUFLOW mesh.

4.5.2 MP Dispersal and Transport Model Development To estimate the proportion of MPs particles transported by tributary creeks, and the tidal inputs of marine MPs to the Brisbane River, six locations, namely, S1–S6 in Fig. 4.13 at the confluence of creeks and at the river mouth were selected as MP particle input source points. To determine the dispersal pattern and transport distance of MP particles, points which are located at different distances and directions from the source points in the main river waterway were identified as monitoring points. As shown in Fig. 4.13, a total of sixteen monitoring points with a distance of 100 and 200 m from source points were selected, namely, MP1-100 (which is 100 m from S1 and S2), MP1-200 (which is 200 m from S1 and S2); MP2-100-UP (which is located 100 m upstream of S3), MP2-200-UP (which is located 200 m upstream of S3), MP2-100-DOWN (which is located 100 m downstream of S3), MP2-200DOWN (which is located 200 m downstream of S3); MP3-100-UP (which is located 100 m upstream of S4), MP3-200-UP (which is located 200 m upstream of S4), MP3-100-DOWN (which is located 100 m downstream of S4), MP3-200-DOWN (which is located 200 m downstream of S4); MP4-100-UP (which is located 100 m upstream of S5), MP4-200-UP (which is located 200 m up stream of S5), MP4-100DOWN (which is located 100 m downstream of S5), MP4-200-DOWN (which is located 200 m downstream of S5); MP5-100 (which is located 100 m upstream of S6), MP5-200 (which is located 200 upstream of S6). To assess the accuracy of the model results, validation was performed by comparing model results with field measured data which has been published previously (He et al. 2020b). Additionally, considering that two field sampling sites were located in the upstream section of the input source points in the model simulation, modelled MPs concentrations were calculated for the remaining twenty points in

S1

MP1-100 MP1-200

MP4-100-UP MP4-200-UP

S5

MP4-100-DOWN MP4-200-DOWN

MP5-100 MP5-200

S6

Fig. 4.13 Selected source and monitoring points adopted for the simulation. Notes: The red dots are MPs input source points (S1–S6), the black bold lines are the monitoring points. S1 is the upper branch of Brisbane River, S2 is the confluence of Bremer River and Brisbane River, S3 is the confluence of Oxley Creek and Brisbane River, S4 is the confluence of Enoggera Creek and Brisbane River, S5 is the confluence of Bulimba Creek and Brisbane River, S6 is Brisbane River mouth

S2

MP2-100-DOWN

S3 MP2-200-DOWN

MP2-100-UP

MP2-200-UP

S4 MP3-100-UP MP3-200-UP

MP3-100-DOWN MP3-200-DOWN

Moreton Bay

62 4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane …

4.5 Risks Associated with MPs Transport and Dispersion

63

accordance with field sampling episodes, namely, in March, June, and September 2018.

4.5.3 Variability of MPs Migration Behaviour in Brisbane River Sediments The particle bed concentration of the modelled MPs at the selected monitoring points is presented in Fig. 4.14. Distinct variability patterns of MPs bed concentrations imply different mobility among the different types. Generally, the variability of MPs bed concentration coincided with their settling velocity and particle density. As shown in Fig. 4.14, significant reduced bed concentrations of PA and PET particles at all monitoring points indicated their limited migration distance. Compared to PP, PA, and PET, PE particles were observed in relatively lower bed concentration at the 100 m monitoring points, while the higher values were in the 200 m monitoring points at all locations over the simulation period (Fig. 4.14). This is attributed to the fact that the relatively lower density of PE particles makes them prone to being suspended for a longer time, and being transported a greater distance rather than being retained in the sediments close to the source points. In contrast, the bed concentration of PA and PET particles, which have relatively high density and settling velocities, had high concentration at 100 m and relatively low concentration at 200 m (Fig. 4.14). Additionally, the dispersal and transport processes of modelled MPs in river sediments were clearly related to the characteristics of the different river sections. For example, the concentration of simulated MPs at MP5-200 was higher compared to MP5-100 due to the combined contribution of upstream transportation and tidal inputs. Additionally, MP5 (river mouth) with relatively high critical shear stress due to the increasing water density and bed shear stress due to the much higher water depth than in the upstream reaches is expected to transport relatively more MPs from source points resulting in a high load of MPs at the monitoring point compared to other monitoring points such as MP4. Considering the variability in the migration behaviour of different MPs and the patchiness associated with different MPs hotspots as shown in Fig. 4.6, it is reasonable to hypothesise that the transport distance of MPs in river sediments is limited. Not all MPs in urban waterways are prone to be transported to marine or other aquatic environments. The majority of MPs (especially those with high particle density) are likely to remain close to where they have been discharged for a relatively long period (He et al. 2021). Consequently, the retained MPs would pose potential risks to both water and sediment quality, as well as to organisms where they are abundantly accumulated. For example, wide occurrence of MPs in the residential, commercial and industrial regions due to the considerable contribution from terrestrial inputs, would result in radiative effects by absorbing and scattering radiation, which can further

Particle bed concentration (kg/m2)

Particle bed concentration (kg/m2)

MP2-200-DOWN

MP2-200-UP

MP2-100-UP

MP2-100-DOWN

MP1-200

MP1-100

Fig. 4.14 Bed concentration of the different MP types for the different monitoring points along the Brisbane River

Particle bed concentration (kg/m2)

64 4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane …

Fig. 4.14 (continued)

Particle bed concentration (kg/m2)

Particle bed concentration (kg/m2)

Particle bed concentration (kg/m2)

MP4-200-UP

MP3-200-DOWN

MP3-100-DOWN

MP4-100-UP

MP3-200-UP

MP3-100-UP

4.5 Risks Associated with MPs Transport and Dispersion

65

MP5-200

Fig. 4.14 (continued)

MP5-100

MP4-100-DOWN

MP4-200-DOWN

4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane …

Particle bed concentration (kg/m2)

Particle bed concentration (kg/m2)

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4.6 Summary

67

alter environmental parameters such as water temperature and nutrient concentrations. Furthermore, due to the continuous breakdown of MP particles, more hazardous additives would be released further deteriorating water and sediment quality of the River. Moreover, the adverse impacts of MPs would extend to the entire urban aquatic system and the marine environment due to their dispersal and transport behaviour (He et al. 2022). Hence, further modelling studies are recommended to derive a greater understanding of the dispersal and ultimate fate of MPs in urban waterways by comprehensively considering various influential factors such as interactions with biofilm and sediment clays.

4.6 Summary The investigation of the Brisbane River over the four different climatic seasons revealed relatively high concentrations of MPs in the sediments, with abundance ranging from 0.18 to 129.20 mg kg−1 . PE, PA and PP were identified as three main polymer types at all sampling sites and sampling periods, with the average proportions accounting for 70%, 12%, and 10% of the total detected MPs, respectively. Other polymer types, namely, PET was found to be about 8% of the total MPs. The most common shapes of MP particles were identified as films, followed by fragments and fibres. Films and fragments were detected in PE and PP particles, whilst fibres were identified in PE, PP and PA particles, and fragments and fibres were only identified in PE particles. Depending on the variability of MPs occurrence in river sediments, MPs hotpots are present in various land use areas and are almost evenly distributed along the Brisbane River. Such a dynamic trend suggests that MP abundance is probably not a land-based, but a distance-based dynamic process in the water flow systems. It is hypothesised that river flow dynamics is the major contributor to MPs abundance. The correlations among MPs, nutrients and metals were assessed. Results showed that all three nutrient parameters have a strong positive relationship with MPs concentration, while negatively correlated to MPs hazard scores. The different correlation patterns of metals with MPs concentration and hazard index can be attributed to different metallic additives used in different plastic materials. For the dispersal and transport behaviour of different MPs, the variability in the concentration of MPs in the sediment bed coincided with their particle density and settling velocity. Sedimental MPs with relatively low density and low settling velocity such as PE and PP have high mobility, while dense MP particles such as PA and PET are more likely to accumulate in river sediments close to the source points. Considering the variability of different MPs dispersal and movement behaviour, the patchiness associated with different plastic hotspots provide valuable information for MPs source tracking in aquatic environments.

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4 Case Study—Risks Posed by MPs Presence and Transport in Brisbane …

References Blettler MCM, Abrial E, Khan FR, Sivri N, Espinola LA (2018) Freshwater plastic pollution: recognizing research biases and identifying knowledge gaps. Water Res 143:416–424. https:// doi.org/10.1016/j.watres.2018.06.015 BMT (2020) STM PTM user manual. BMT WBM, Australia Brady JP, Ayoko GA, Martens WN, Goonetilleke A (2015) Development of a hybrid pollution index for heavy metals in marine and estuarine sediments. Environ Monit Assess 187(5):306. https:// doi.org/10.1007/s10661-015-4563-x Bušatli´c I, Haraˇci´c N, Merdi´c N (2009) XRF spectrometer sample preparation by using fused beads technique Duodu GO, Goonetilleke A, Allen C, Ayoko GA (2015) Determination of refractive and volatile elements in sediment using laser ablation inductively coupled plasma mass spectrometry. Anal Chim Acta 898:19–27. https://doi.org/10.1016/j.aca.2015.09.033 Duodu GO, Goonetilleke A, Ayoko GA (2017) Potential bioavailability assessment, source apportionment and ecological risk of heavy metals in the sediment of Brisbane River estuary, Australia. Marine Pollut Bull 117(1):523–531. https://doi.org/10.1016/j.marpolbul.2017.02.017 Hahladakis JN, Velis CA, Weber R, Iacovidou E, Purnell P (2018) An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. J Hazard Mater 344:179–199. https://doi.org/10.1016/j.jhazmat.2017.10.014 He B, Duodu GO, Rintoul L, Ayoko GA, Goonetilleke A (2020a) Influence of microplastics on nutrients and metal concentrations in river sediments. Environ Pollut 263:114490. https://doi.org/ 10.1016/j.envpol.2020.114490 He B, Goonetilleke A, Ayoko GA, Rintoul L (2020b) Abundance, distribution patterns, and identification of microplastics in Brisbane River sediments, Australia. Sci Total Environ 700:134467. https://doi.org/10.1016/j.scitotenv.2019.134467 He B, Wijesiri B, Ayoko GA, Egodawatta P, Rintoul L, Goonetilleke A (2020c) Influential factors on microplastics occurrence in river sediments. Sci Total Environ 738:139901. https://doi.org/10. 1016/j.scitotenv.2020.139901 He B, Smith M, Egodawatta P, Ayoko GA, Rintoul L, Goonetilleke A (2021) Dispersal and transport of microplastics in river sediments. Environ Pollut 116884. https://doi.org/10.1016/j.envpol.2021. 116884 He B, Liu A, Duan H, Wijesiri B, Goonetilleke A (2022) Risk associated with microplastics in urban aquatic environments: a critical review. J Hazard Mater 439:129587. https://doi.org/10. 1016/j.jhazmat.2022.129587 He B, Liu A, Duodu GO, Wijesiri B, Ayoko GA, Goonetilleke A (2023) Distribution and variation of metals in urban river sediments in response to microplastics presence, catchment characteristics and sediment properties. Sci Total Environ 856:159139. https://doi.org/10.1016/j.scitotenv.2022. 159139 Hidalgo-Ruz V, Gutow L, Thompson RC, Thiel M (2012) Microplastics in the marine environment: a review of the methods used for identification and quantification. Environ Sci Technol 46(6):3060– 3075. https://doi.org/10.1021/es2031505 Holmes LA, Turner A, Thompson RC (2014) Interactions between trace metals and plastic production pellets under estuarine conditions. Marine Chem 167:25–32. https://doi.org/10.1016/j.mar chem.2014.06.001 Jovanovic D, Gelsinari S, Bruce L, Hipsey M, Teakle I, Barnes M, Coleman R, Deletic A, McCarthy DT (2019) Modelling shallow and narrow urban salt-wedge estuaries: evaluation of model performance and sensitivity to optimise input data collection. Estuarine Coastal Shelf Sci 217:9–27. https://doi.org/10.1016/j.ecss.2018.10.022 Lagarde F, Olivier O, Zanella M, Daniel P, Hiard S, Caruso A (2016) Microplastic interactions with freshwater microalgae: hetero-aggregation and changes in plastic density appear strongly dependent on polymer type. Environ Pollut 215:331–339. https://doi.org/10.1016/j.envpol.2016. 05.006

References

69

Lithner D, Larsson A, Dave G (2011) Environmental and health hazard ranking and assessment of plastic polymers based on chemical composition. Sci Total Environ 409(18):3309–3324. https:// doi.org/10.1016/j.scitotenv.2011.04.038 Liu G, Zhu Z, Yang Y, Sun Y, Yu F, Ma J (2019) Sorption behavior and mechanism of hydrophilic organic chemicals to virgin and aged microplastics in freshwater and seawater. Environ Pollut 246:26–33. https://doi.org/10.1016/j.envpol.2018.11.100 Ma Y, Mummullage S, Wijesiri B, Egodawatta P, McGree J, Ayoko GA, Goonetilleke A (2021) Source quantification and risk assessment as a foundation for risk management of metals in urban road deposited solids. J Hazard Mater 408:124912. https://doi.org/10.1016/j.jhazmat.2020. 124912 Martellini T, Guerranti C, Scopetani C, Ugolini A, Chelazzi D, Cincinelli A (2018) A snapshot of microplastics in the coastal areas of the Mediterranean Sea. TrAC Trends Anal Chem 109:173– 179. https://doi.org/10.1016/j.trac.2018.09.028 Miranda LS, Wijesiri B, Ayoko GA, Egodawatta P, Goonetilleke A (2021) Water-sediment interactions and mobility of heavy metals in aquatic environments. Water Res 202:117386. https://doi. org/10.1016/j.watres.2021.117386 Pathirana C, Ziyath AM, Jinadasa KBSN, Egodawatta P, Sarina S, Goonetilleke A (2019) Quantifying the influence of surface physico-chemical properties of biosorbents on heavy metal adsorption. Chemosphere 234:488–495. https://doi.org/10.1016/j.chemosphere.2019.06.074 Pathirana C, Ziyath AM, Egodawatta P, Bandara NJGJ, Jinadasa KBSN, Bandala ER, Wijesiri B, Goonetilleke A (2022) Biosorption of heavy metals: Transferability between batch and column studies. Chemosphere 294:133659. https://doi.org/10.1016/j.chemosphere.2022.133659 Rayment GE, Lyons DJ (2011) Soil chemical methods: Australasia. CSIRO Publishing Rayment GE, Lyons DJ (2012) New, comprehensive soil chemical methods book for Australasia. Commun Soil Sci Plant Anal 43(1–2):412–418. Retrieved from ://WOS:000301639200042 Rodrigues MO, Abrantes N, Gonçalves FJM, Nogueira H, Marques JC, Gonçalves AMM (2018) Spatial and temporal distribution of microplastics in water and sediments of a freshwater system (Antuã River, Portugal). Sci Total Environ 633:1549–1559. https://doi.org/10.1016/j.scitotenv. 2018.03.233 Rodríguez-Narvaez OM, Goonetilleke A, Perez L, Bandala ER (2021) Engineered technologies for the separation and degradation of microplastics in water: a review. Chem Eng J 414:128692. https://doi.org/10.1016/j.cej.2021.128692 Soulsby R (1997) Dynamics of marine sands. Thomas Telford Publishing Turner A, Holmes LA (2015) Adsorption of trace metals by microplastic pellets in fresh water. Environ Chem 12(5):600–610. https://doi.org/10.1071/EN14143 Watanabe M, Inoue H, Yamada Y, Feeney M, Oelofse L, Kataoka Y (2013) XRF analysis of high gain-on-ignition samples by fusion method using fundamental-parameter method. Powder Diffract 28(2):132–136. Retrieved from ://WOS:000319981000015 Wijesiri B, Liu A, Jayarathne A, Duodu G, Ayoko GA, Chen L, Goonetilleke A (2021) Influence of the hierarchical structure of land use on metals, nutrients and organochlorine pesticides in urban river sediments. Ecol Eng 159:106123. https://doi.org/10.1016/j.ecoleng.2020.106123 Wijesiri B, Liu A, Miguntanna N, He B, Goonetilleke A (2022) Understanding nutrient dynamics for effective stormwater treatment design. Sci Total Environ 850:157962. https://doi.org/10.1016/ j.scitotenv.2022.157962 Willis JP (2010) XRF sample preparation PANalytical B.V., The Netherlands Wu CC, Bao LJ, Liu LY, Shi L, Tao S, Zeng EY (2017) Impact of polymer colonization on the fate of organic contaminants in sediment. Environ Sci Technol 51(18):10555–10561. https://doi.org/ 10.1021/acs.est.7b03310

Chapter 5

Practical Implications and Recommendations for Further Research

Abstract This chapter provides a consolidated summary of the research study outcomes on the investigation of the environmental risks in relation to MPs occurrence and migration in urban waterways. The knowledge created is expected to provide practical guidance and recommendations for the formulation of effective management and mitigation strategies for MPs in urban aquatic environments. This chapter also identifies key areas where significant knowledge gaps exist in relation to MPs source tracking, interaction mechanisms (release and sorption capacity) with metals and organic contaminants, as well as the environmental consequences to urban waterways from a risk perspective. Keywords MPs pollutants · Distribution patterns · Associated contaminants · Environmental risks · Urban waterways

Abbreviations Al As Ca Cd Co Cr Cs Cu DDT DI Water DOA DEHA DEP Fe FT-IR

Aluminium Arsenic Calcium Cadmium Cobalt Chromium Caesium Copper Dichloro-diphenyl-trichloroethane Deionized water Di-octyl adipate Di-(2-ethylhexyl) adipate Diethyl phthalates Iron Fourier Transform Infrared

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 B. He et al., Environmental Risks Posed by Microplastics in Urban Waterways, SpringerBriefs in Water Science and Technology, https://doi.org/10.1007/978-981-99-0628-4_5

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HDPE ICP-MS MPs Mg Mn NaCl NaI Ni NOAA PA PAHs PAN PC PCA PCBs PE PET PLA POM PP PS PUR PVC PVDC QA QC Se TC TN TP Zn ZnCl2

5 Practical Implications and Recommendations for Further Research

High-density polyethylene Inductive Coupled Plasma-Mass Spectroscopy Microplastics Magnesium Manganese Sodium chloride Sodium iodide Nickel National Oceanic and Atmospheric Administration Polyamide Polycyclic Aromatic Hydrocarbons Polyacrylonitrile Polycarbonate Principal Component Analysis Polychlorinated biphenyls Polyethylene Polyethylene terephthalate Polylactic acid Polyoxymethylene Polypropylene Polystyrene Polyurethane Polyvinyl chloride Polyvinyl dichloride Quality assurance Quality control Selenium Total Carbon Total Nitrogen Total Phosphorus Zinc Zinc chloride

5.1 Implication of Plastic Pollutants in Urban Waterways 5.1.1 Tracking Plastic Pollutants There is wide agreement that MPs enter aquatic environments from a diversity of terrestrial sources through various pathways such as stormwater runoff and wastewater discharge. Land use type and anthropogenic activities are identified as sources for

5.1 Implication of Plastic Pollutants in Urban Waterways

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a range of different plastic wastes to urban waterways as illustrated in Chap. 2. Additionally, the presence and movement of MPs are governed by the hydraulic conditions such as flow velocity and catchment characteristics. Industrial and commercial activities are likely to contribute large amounts of hazardous plastics, such as polyvinyl chloride (PVC) and polyethylene terephthalate (PET), which would result in high risk to the environment due to toxic leachate as described in Chap. 3. Hence, appropriate mitigation measures can be implemented at locations close to the potential source areas, and specific waterway sections which have favourable conditions for plastic transport, in order to minimize the potential emission of waste plastics from terrestrial sources to aquatic environments. Accurate interpretation of MP sources and fate based on transport modelling outcomes is the key to designing effective strategies to mitigate waste plastic pollution in urban waterways. A similar approach to the model developed to understand MPs migration in river sediments as discussed in Chap. 4 can be employed by urban water management personnel to predict the source to fate continuum of different plastic pollutants in urban waterways. The model presented in Chap. 4 is specific to the case study river. However, the approach is generic and provides the basis for application to other geographical areas. The transport distances as determined from the model for the different MPs can further provide the basis to estimate and predict the regional average concentrations of different plastic particles, and contribute to enhancing waste control measures accordingly. Furthermore, the model study results discussed in Chap. 4, would not only benefit MPs management in the Brisbane River catchment from a risk perspective, the physicochemical parameters of the different MP species and approaches adopted for understanding their hydrodynamic behaviour can also be employed to determine the variation in MPs distribution and mobility in waterbodies worldwide.

5.1.2 Implementation of Waste Plastics Management An efficient waste management strategy is expected to result in zero plastic pollutants entering the environment. However, high concentration of floating and sedimental MPs in the aquatic environment have been detected worldwide. The escalating disposal of plastics, combined with the considerable abundance of waste plastic particles present in aquatic environments will undoubtedly lead to the increase in adverse consequences to the aquatic environment. Removal of MPs present in aquatic environments is not economically or logistically feasible. Hence, it is crucial to determine the potential harmful effects of different MPs to the environment based on their abundance, which in turn would provide the baseline knowledge to strengthen management and regulatory measures. MP particles with high hazardous chemical compounds are expected to result in the emission of toxic leachate as a result of degradation, which can thus pose potential threats to the surrounding environment. For example, phthalates which are regarded as among the most environmentally hazardous substances in plastic materials, have

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5 Practical Implications and Recommendations for Further Research

been used as plasticizers that make up more than 60% by weight in most plastic products such as PVC. During the degradation process of plastics, the toxic leachate would increase the concentration of ambient chemical compounds with long lasting effects. Additionally, metals used as catalysts and stabilizers are the indispensable components in plastics. The consequent toxic metal leachate elevates concerns in relation to the pollution level of metal contaminants in aquatic environments. As such, an in-depth understanding of the toxic properties of different plastic leachate would provide guidance to urban water management personnel to formulate effective plastic waste mitigation strategies, as well as predict and interpret the water environmental quality resulting from the presence of different plastic pollutants. Regulators can limit the use of certain polymer types which are manufactured with highly hazardous additives for specific applications. For example, single use packaging materials such as food containers and drink bottles should not be manufactured using PET or PVC in order to reduce the potential waste discharge of such plastic waste to the environment. Additionally, industrial and high traffic volume regions would be likely to contribute large amounts of plastic pollutants such as PVC and rubber that incorporate highly hazardous compounds, resulting in high risk to environment quality after they enter receiving waters. Hence, effective recycling systems and enhanced wastewater and stormwater treatment measures should be implemented to shorten the lifespan of plastic waste in the water environment in order to minimise toxic additives being released once they have been discharged. Additionally, in the case of plastics with relatively lower hazard risks such as PE and PP, which are mostly used in daily consumer items and commonly detected close to residential and commercial areas, appropriate treatment techniques can be implemented at locations close to the potential source areas to prevent their impacts on the aquatic environment. Moreover, regulatory waste management measures should be applied to restrict the disposal and landfill of such plastics in agricultural areas. This is because, these plastics are widely used in crop production and generally transported directly to the adjacent aquatic environment by stormwater runoff. Consequently, the adsorbed organic contaminants such as pesticides that are widely used in agriculture would compound the risks to both, water and sediment quality.

5.2 Recommendations for Further Research Current research studies on aquatic MPs have established a meaningful theoretical basis for the investigation of MPs abundance based on the available concentrations and types. However, the majority of the available knowledge on MPs source tracking commonly link different MPs’ physicochemical properties to catchment characteristics. Other factors such as precipitation and wind characteristics are rarely considered. Additionally, current research in terms of catchment influence on MPs presence are essentially qualitative evaluations. The quantification of different potential emission sources that contributes to the presence of different MPs species in urban waterways still remains largely unknown. For example, MPs present at a study site can be either

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freshly released from emission sources or as a result of migration from past deposition to the waterway. Therefore, it is challenging to identify the exact sources of detected MPs for meaningful source tracking. Although modelling studies indicate the limited transport distance of MP pollutants, it should be noted that these models were developed based on classical sediment transport theory using the physicochemical properties of virgin plastics. As a crucial parameter in the migration process, MPs density can be largely altered during degradation, biofilm accumulation and the interaction with sediment clays. Such interactions between MPs and the ambient matrix can be largely influenced by factors including the initial physicochemical properties and the time spent by the MPs in different aquatic environments. This would result in different particle densities of MPs. Further, this would in turn, influence the dispersal and migration processes of MP particles. Therefore, methodologies for the quantitative evaluation and determination of the age and indicative microorganism population in different MPs in relation to changes to particle density is needed. This would enable the determination of more realistic migration processes of different MPs under the influence of natural factors such as hydraulic parameters and the interaction with biofilms and sediment clays. This in turn would enable the more accurate interpretation of the different sources of plastic pollutants. Ecotoxicity is another major concern in relation to plastic pollutants in aquatic environments. The currently available methodologies for the assessment of risk to the aquatic environment and organisms is far from being comprehensive. Current approaches for the assessment of risk of MPs is solely based on their type and abundance, which is an extremely limited approach. Due to the release and sorption capacity of plastics for typical contaminants present in aquatic systems such as metals and persistent organic compounds, different plastic types with different degradation levels would certainly result in different toxicity levels. However, the interaction mechanisms such as the release and sorption capacity between different plastic types and contaminants existing in the ambient environment are not completely known. Consequently, this constrains the in-depth understanding of the resulting toxicity of the mixture of contaminants associated with the MPs. Hence, a comprehensive risk assessment framework for the mixture toxicity of different plastics under different degradation status with various associated contaminants is essential from a risk assessment perspective.

Index

A Abundance, 3, 5, 9, 10, 19, 20, 32, 33, 39, 40, 54, 59, 67, 73–75 Additives, 3, 25, 28, 29, 32, 59, 60, 67, 74 Adsorb, 25, 31, 33, 74 Adsorption, 31–33, 56 Anthropogenic activities, 3, 7, 8, 13, 72 Atmospheric, 3, 13, 15, 18

B Biodegradation, 16, 21 Biofilm, 22, 32, 59, 60, 67, 75

Foam, 5, 7 Fourier-Transform Infrared (FT-IR), 50 Fragment, 4, 5, 7, 10, 16, 19, 21, 55, 67

H Hazard index, 37, 56, 67 Hazard score, 57, 67 Hydrodynamic conditions, 13, 15, 19–21, 53

C Colonisation, 13, 15, 22, 32, 59

I Inductive Coupled Plasma-Mass Spectroscopy (ICP-MS), 49 Iron (Fe), 60

D Degradation, 4, 5, 9, 10, 13, 16, 20–22, 28, 29, 31, 32, 55, 60, 73–75 Density separation, 9, 49, 50 Dispersal, 8, 33, 39, 60, 61, 63, 67, 75 Distribution pattern, 3, 14, 15, 19, 21, 26, 39, 53, 72

M Metal, 27, 29, 31, 37, 40, 49, 53, 59, 67, 71, 74 Microorganisms, 22, 25, 32, 59 Migration, 3, 8, 16, 21, 25, 27, 28, 32, 39, 60, 63, 71, 73 Morphological characteristics, 1, 3, 5, 9, 52

E Environmental factors, 13, 15, 22, 27, 29 Environmental risk, 2, 13, 25, 37, 39, 71

N Nutrients, 17, 37, 59, 67

F Fibres, 5, 18, 55, 56, 67 Film, 3, 5, 7, 9, 55, 56, 67

O Organic compounds, 25, 28, 29, 31 Organisms, 5, 33, 56, 63, 75

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023 B. He et al., Environmental Risks Posed by Microplastics in Urban Waterways, SpringerBriefs in Water Science and Technology, https://doi.org/10.1007/978-981-99-0628-4

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78 P Particle transport model, 60 Pellet, 4, 5, 7, 9, 16, 31 Photothermal degradation, 13, 15, 20, 21 Plastic waste, 3, 17, 55, 73 Polyamide (PA), 2, 55 Polyethylene (PE), 2 Polyethylene Terephthalate (PET), 2, 73 Polypropylene (PP), 2 Polystyrene (PS), 2, 59 Polyvinyl Chloride (PVC), 3, 55, 73 Primary MPs, 4, 5, 15, 16 Principal Component Analysis (PCA), 59 Q Quality Assurance (QA), 50 Quality Control (QC), 50 R Release, 27–29, 33, 71, 75 S Secondary MPs, 4, 5, 15 Sediments, 4, 5, 8, 9, 19, 20, 27, 31, 37, 40, 50, 52, 53, 58, 59, 63, 67, 73

Index Settling, 8, 21, 27, 37, 50, 61, 63, 67 Sodium chloride (NaCl), 49 Sodium iodide (NaI), 49

T Terrestrial, 1, 3, 16, 21, 22, 33, 54, 63, 72 Total Carbon (TC), 40 Total Nitrogen (TN), 40 Total Phosphorus (TP), 40 Toxicological threat, 27, 32 Transport, 3, 15, 19–21, 27, 33, 37, 40, 48, 54, 59–61, 67, 73 TUFLOW FV, 60 TUFLOW FV PTM, 60

U Urban waterway, 8

W Water column, 7–9, 21, 27, 40

Z Zinc chloride (ZnCl2 ), 49