Toxic Effects of Micro- and Nanoplastics E-Book
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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
This book provides in-depth coverage of the sources, dispersion, life cycle assessment strategies, physico-chemical interactions, methods of analysis, toxicological investigation, and remediation strategies of micro and nanoplastics.
Micro and nanoplastics are the degradation products of large plastic compounds. These degraded polymers enter into the natural environment, including air, water, and food, which leads to various significant threats to human health. The nature of these micro and nanoplastics is persistent and consequently accumulates in the exposed person’s body. Research into microplastics has shown that these particles accumulate in various human organs and impart detrimental effects on humans. To safeguard human health, analysis and remediation strategies are necessary. This book provides a comprehensive overview in 24 chapters on the source, distribution, life cycle assessment strategies, physico-chemical interactions, methods of analysis, toxicological investigation, and remediation strategies of micro and nanoplastics.
Audience
This book is a valuable resource for chemists and polymer scientists in various industries including plastics, fisheries, food and beverages, environmental sciences, agriculture, and medicine, as well as government policymakers.
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Veröffentlichungsjahr: 2024
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Preface
1 Aging Process of Microplastics in the Environment
1.1 Introduction
1.2 Impact of MPs on the Environment
1.3 Pristine and Aged Microplastics
1.4 Influence of Aging Processes in the Properties of MPs
1.5 Simulation in the Laboratory of the Different Aging Effects
1.6 Conclusion
Acknowledgments
References
2 Life Cycle Assessment (LCA) of Bioplastics
2.1 Introduction
2.2 Purpose and Approach of this Chapter
2.3 Development of Life Cycle Assessments for Bioplastics
2.4 Discussion
2.5 Concluding Remarks
References
3 Micro- and Nanoplastics—An Invisible Threat to Human Health
3.1 Introduction
3.2 Routes of Exposure
3.3 Phenomenon of Microplastics in Nourishment and Nutrients
3.4 Impact of Microplastics and Nanoplastics on Mammalian Health
3.5 Nanoplastics and Microplastics: Effects on Environment and Marine Life
3.6 Conclusions
Acknowledgments
Conflict of Interest
References
4 Microplastics and Nanoplastics and Related Chemicals: The Physical–Chemical Interactions
4.1 Introduction to Micro- and Nanoplastics
4.2 Sources and Distribution of Micro- and Nanoplastics
4.3 Ecological Impacts of Micro- and Nanoplastics
4.4 Food Contamination and Human Exposure to Micro- and Nanoplastics
4.5 Toxicological Effects of Micro- and Nanoplastics on Human Health
4.6 Conclusions and Recommendations for Mitigating the Toxic Effects of Micro- and Nanoplastics
References
5 Microplastics and Nanoplastics: Sources, Distribution, Behaviors, and Fate
List of Abbreviations
5.1 Micro- and Nanoplastics: Principles and Sources
5.2 Micro- and Nanoplastic Behavior
5.3 Micro- and Nanoplastics’ Distribution and Fate: From Terrestrial and Aquatic Environments to the Human Body
5.4 The Effect of Abiotic and Biotic Factors on MNPs’ Behavior and Fate
5.5 Conclusions and Future Perspectives
References
6 Microplastics and Nanoplastics in Food
6.1 Introduction
6.2 Sources of Micro-Nanoplastics Affecting Food
6.3 Impact of Micro-Nanoplastics
6.4 Direct Impact on Human Health
6.5 Affecting the Food Chain
6.6 Detection of Micro-Nanoplastics in Food
6.7 Conclusion
References
7 Microplastics: Properties, Effect on the Environment and Removal Methods
7.1 An Insight Into Microplastics (MPs)
7.2 Microplastic Definitions
7.3 Properties of MPs
7.4 Primary and Secondary Microplastics
7.5 Microbeads
7.6 Impacts of MPs
7.7 Global Initiatives
7.8 Conclusion
References
8 Identification, Quantification, and Presence of Microplastics and Nanoplastics in Beverages Around the World
8.1 Introduction
8.2 Methodology
8.3 Results
8.4 Microplastic Concentrations in Beverages
8.5 Microplastic Characterization in Beverages
8.6 Human Exposure
8.7 Conclusions
References
9 Microplastics and Nanoplastics in Terrestrial Systems
9.1 Introduction
9.2 Micro/Nanoplastics in Soil
9.3 Micro/Nanoplastics in Plants
9.4 Micro/Nanoplastics in Terrestrial Organism
9.5 Conclusion
References
10 Microplastics in Cosmetics and Personal Care Products
10.1 Introduction
10.2 Methodology
10.3 Results
10.4 Characterization of Microplastics in PCPs and Cosmetics
10.5 Interaction Between Microplastics from PCPs and Other Substances
10.6 Toxicity of Microplastics from Personal Care Products and Cosmetics
10.7 Worldwide Bans on Microbeads in PCPs and Cosmetics
10.8 Conclusions
References
11 Study on Microplastic Content in Cosmetic Products and Their Detrimental Effect on Human Health
11.1 Introduction
11.2 Cosmetic Products in India
11.3 Source of Plastics and Microplastics
11.4 Uptake and Bio-Accumulation of Microplastics
11.5 Effect of Microplastic Exposure on Human Health
11.6 Alternatives of Microplastics in Cosmetic Products
11.7 Conclusions
Acknowledgments
References
12 Effects of Micro- and Nanoplastics on Human Genome
12.1 Introduction
12.2 Source of Micro- and Nanoplastics
12.3 Pathways Through Which Micro- and Nanoplastics Enter the Food Chain
12.4 Harmful Impacts of Micro- and Nanoplastics on Human Health
12.5 Impacts of Micro- and Nanoplastics on the Genome of Humans
12.6 Toxic Effects of Micro- and Nanoplastics
12.7 Case Study on a Small Regional Place of India (Puducherry)
12.8 Conclusion
References
13 Harmful Effects of Plastics, Microplastics, and Nanoplastics
13.1 Introduction
13.2 Generation of MPs and NPs
13.3 Techniques for MP and NP Measurement
13.4 Various Methods for the Degradation of Plastics
13.5 Harmful Effects of Plastics, Microplastics, and Nanoplastics
13.6 Measures to Avoid the Further Extension of Harmful Effects of Plastics, Microplastics, and Nanoplastics
13.7 Conclusions
References
14 Hazardous Effects of Microplastics and Nanoplastics in Marine Environment
14.1 Introduction
14.2 Fate and Sources of Microplastics
14.3 Minimizing the Microplastics in the Environment
14.4 Severance of Microplastics from Water and Sediments
14.5 Marine Microbial Strains Associated in Degrading Microplastics
14.6 Work Done in our Laboratory
14.7 Conclusions
Acknowledgments
References
15 Human Toxicity of Nano- and Microplastics
15.1 Introduction
15.2 Basic Toxicology Concepts
15.3 Challenges and Opportunities for Evaluation of Toxicity in Humans
15.4 Toxicity Studies With Nano- and Microplastics
15.5 Toxicity of Nano- and Microplastic Reported in the Literature
15.6 Conclusions
References
16 Plastic-Related Chemicals: Occurrence in Environment and Ecotoxicological Impacts
16.1 Introduction
16.2 Plasticizers
16.3 Flame Retardants
16.4 Human Exposure to Flame Retardants
16.5 Conclusion
Acknowledgments
References
17 The Invisible Threat: Micronanoplastic Materials
17.1 Introduction
17.2 Microplastic and Toxic Chemicals
17.3 Organic Pollutants
17.4 Microplastic Toxic Chemical Interaction
17.5 Toxicity to Human
17.6 Toxicity to Environment
17.7 Impact of MiNaPs on Marine Environment and Terrestrial Habitat
17.8 Conclusion
References
18 Comparative Analysis of the Toxicity of Micro- and Nanoplastics along with Nanoparticles on the Ecosystem
18.1 Introduction
18.2 Literature Survey
18.3 Exposure to Ecosystem and Translocation
18.4 Challenges and Precautions
18.5 Conclusions
References
19 Methods for Micro- and Nanoplastics Analysis
19.1 Introduction
19.2 Micro- and Nanoplastics: Source, Occurrence, and Risks
19.3 Pre-Treatment of Micro- and Nanoplastic Samples
19.4 Methods for Characterization, Identification, and Quantification of Micro- and Nanoplastics
19.5 Conclusions
References
20 New Approaches for Micro(Nano)Plastics Analysis
20.1 Introduction
20.2 Global Plastic Production and Its Waste Generation
20.3 Sources and Health Effects of Micro- and Nanoplastics
20.4 Sample Collection Methods
20.5 Emerging Analytical Approaches
20.6 Single Analytical Methods
20.7 Hyphenated Analytical Techniques
20.8 Current Trends and Future Perspectives
20.9 Conclusions
References
21 Enzyme-Catalyzed Biodegradation of Micro- and Nanoplastics
21.1 Introduction
21.2 Degradation of Plastics
21.3 Enzyme-Based Degradation of Plastics
21.4 Conclusion
References
22 Remediation Strategies for Micro(Nano)Plastics
22.1 Introduction
22.2 Methods for the Removal of Micro(Nano)Plastics from the Environment
22.3 Comparison of Different Removal Methods
22.4 Prevention and Reduction of Microplastic Pollution
22.5 Conclusions
References
23 Removal of Microplastics and Nanoplastics From Water
23.1 Introduction
23.2 Sponge/Aerogel Materials to Remove MPs and NPs
23.3 Materials With Metals to Remove MPs and NPs
23.4 Biochar as Material to Remove the MPs and NPs
23.5 Additional Materials to Remove MPs and NPs
23.6 Conclusion
References
24 Microplastics and Nanoplastics in Aquatic Systems
24.1 Introduction
24.2 A Theoretical Assessment of MP and NP Migration and Fate Aquatic Environment
24.3 Pollution in Marine Environment
24.4 Toxicity Comparison of MPs and NPs
24.5 Regulatory Policy
24.6 Environmental Implication and Conclusion
Acknowledgments
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Physical and chemical changes of MPs after suffering an aging proces...
Chapter 2
Table 2.1 Functional unit and scope.
Table 2.2 Plastics and bioplastics used in each case study.
Table 2.3 Applications of plastics and bioplastics assessed in life cycle anal...
Table 2.4 Impact methods and impact categories selected per study.
Table 2.5 End-of-life scenarios.
Table 2.6 Main results of each case study.
Chapter 4
Table 4.1 Health effects and nature of macro- and nanoplastics.
Chapter 5
Table 5.1 Applications and general properties of plastic polymers.
Chapter 6
Table 6.1 Characteristics of various detection methods used for identifying MP...
Chapter 7
Table 7.1 Different microorganisms used for the bioremediation of microplastic...
Chapter 8
Table 8.1 Proportion of beverages with MP and mean concentrations (pieces/L).
Table 8.2 Microplastic range sizes reported in the reviewed literature.
Table 8.3 Human exposure to microplastics through the reviewed beverages.
Chapter 9
Table 9.1 Effects of micro/nanoplastics on higher plants.
Chapter 10
Table 10.1 Number of samples and reported dimensions (n = 183).
Table 10.2 Toxicity tests of microplastics from PCPs.
Chapter 11
Table 11.1 Functions of different plastics and microplastics as ingredients in...
Table 11.2 The significant toxic effects of plastics and microplastics on huma...
Chapter 13
Table 13.1 The quantity of MPs taken from various areas.
Chapter 14
Table 14.1 Bacterial and fungal strains depicting the biodegradation of plasti...
Table 14.2 List of microbial strains and the types of plastic which they degra...
Chapter 15
Table 15.1 Toxicity types based on exposure conditions and toxic effects.
Table 15.2 Types of animal studies. Adapted from [16].
Table 15.3 Types of cells or tissues used in toxicity studies. Adapted from [3...
Chapter 16
Table 16.1 Occurrence of plasticizers in the environment, concentration ranges...
Table 16.2 Occurrence of NBFRs and OPES in the environment, concentration rang...
Chapter 17
Table 17.1 Harmful effect of plastic additives on human health.
Table 17.2 Study on different kinds of contaminants present in toxic chemicals...
Chapter 18
Table 18.1 Examples of microbial community, invertebrates, and fish species to...
Table 18.2 Sources, targets, factors, and toxicity of different NPs [6].
Chapter 19
Table 19.1 Characterization and identification methods of micro- and nanoplast...
Table 19.2 Characterization and identification methods of micro- and nanoplast...
Table 19.3 Identification and quantification methods of micro- and nanoplastic...
Table 19.4 Identification and quantification methods of micro- and nanoplastic...
Chapter 20
Table 20.1 Common sampling methods employed for the analysis of microplastics ...
Chapter 22
Table 22.1 Adsorbents reported in the reviewed literature: characteristics and...
Table 22.2 Sand filtration in literature for MP removal,
Table 22.3 Ultrafiltration in literature for MP removal.
Table 22.4 Membrane filtration in literature for MP removal.
Table 22.5 Investigation of coagulants for microplastic removal from different...
Table 22.6 Microplastic removal efficiency.
Table 22.7 Composition of studied vermicomposts. Source: Author’s elaboration ...
Table 22.8 Comparison of different methods for the removal of microplastics.
Chapter 23
Table 23.1 Summary of sponge/aerogel materials for the removal of MPs and NPs.
Table 23.2 Summary of materials and metals used to remove MPs and NPs.
Table 23.3 Summary of the biochar to remove MPs and NPs.
Chapter 24
Table 24.1 Demonstration of the occurrence of MPs in various aquatic organisms...
Table 24.2 Illustration of ecotoxicity investigates using NPs in marine and fr...
List of Illustrations
Chapter 2
Figure 2.1 Stages of the life cycle analysis.
Figure 2.2 Hierarchy of information search.
Figure 2.3 Percentage of studies that assessed each impact category. GWP, glob...
Chapter 3
Figure 3.1 Route of exposure of microplastics and nanoplastics.
Chapter 4
Figure 4.1 Pathway of micro- and nanoplastic contamination in food chain.
Chapter 5
Figure 5.1 Sources and distribution of MNPs. Mulch films, landfills, WWTPs, an...
Figure 5.2 WWTPs unit operations and procedures. Each unit can trap and transf...
Chapter 6
Figure 6.1 Conversion of plastic waste into microplastics and nanoplastics und...
Figure 6.2 Routes of entering MPs and NPs into food and the human body.
Figure 6.3 Evidence of polymer-based MPs found in blue mussels by the Norwegia...
Figure 6.4 SEM images of MPs detected in (a) raw water, (b) treated water, and...
Figure 6.5 MPs found in meat when cutting over cutting boards differ in color ...
Figure 6.6 Mechanisms by which MPs and NPs affect plants.
Chapter 7
Figure 7.1 Overview of different methods for eliminating MPs
Figure 7.2 Chemical method for removal of MPs [34].
Chapter 8
Figure 8.1 Article research and selection process.
Figure 8.2 Countries where microplastic studies were performed.
Figure 8.3 Common steps for the analysis of microplastics in food and beverage...
Figure 8.4 Distribution of the types of drinks studied. Note: The “Others” cat...
Figure 8.5 Material of the containers of the analyzed beverages.
Figure 8.6 Sources of MP by type of beverage.
Figure 8.7 Common reported microplastic types in the reviewed literature.
Figure 8.8 Common reported microplastic colors in reviewed literature.
Figure 8.9 Common reported microplastic chemical composition in the reviewed l...
Chapter 9
Figure 9.1 Conceptual figure of various sources of micro- and nanoplastics in ...
Figure 9.2 Transport mechanism of micro/nanoplastics.
Chapter 10
Figure 10.1 Publication years of the selected articles.
Figure 10.2 Country of origin from the institutions of the selected articles. ...
Figure 10.3 Percentual distribution of samples by type of sample.
Figure 10.4 Percentual distribution of samples by type of product.
Figure 10.5 Countries of origin of products which included this information (n...
Figure 10.6 Percentage distribution of the most common forms of microplastics ...
Figure 10.7 Percentage distribution of color in microplastics from PCPs and co...
Figure 10.8 Histogram of the frequency of lowest range values reported for sam...
Figure 10.9 Histogram of frequency of lowest range values reported for sampled...
Figure 10.10 Distribution of microbeads materials (natural, polymers, and biod...
Figure 10.11 Distribution of extraction methods from PCPs and cosmetics.
Figure 10.12 Distribution of particle size analysis methods for microplastics ...
Figure 10.13 Distribution of polymer-type analysis methods for microplastics i...
Figure 10.14 Countries within the European region with legal or administrative...
Figure 10.15 Countries outside the European region with legal or administrativ...
Chapter 11
Figure 11.1 Classification of cosmetics by Food and Drug Administration (FDA).
Figure 11.2 Flow chart of different cosmetic products widely available in the ...
Figure 11.3 Cosmetic product market share in India for 2021. The data collecte...
Figure 11.4 Schematic representation of three key routes for microplastics ent...
Chapter 12
Figure 12.1 Classification of plastics and their derived products due to envir...
Figure 12.2 Route of microplastic and nanoplastic transport to humans through ...
Figure 12.3 Pathways through which micro- and nanoplastics get exposed to tiss...
Figure 12.4 Interaction of microplastics (MPs) with cellular biomolecules (DNA...
Chapter 13
Figure 13.1 Factors responsible for the formation of MPs.
Figure 13.2 Replacement of plastic materials to biodegradable or eco-friendly ...
Chapter 15
Figure 15.1 Drug development process of the United States Food and Drug Admini...
Figure 15.2 Samples used to perform toxicity tests with nano- and microplastic...
Figure 15.3 Percentage of studies that investigated nano- and microplastics an...
Figure 15.4 Types of nano- and microplastics used in toxicological studies ana...
Figure 15.5 Genotoxic effects of nano- and microplastics.
Chapter 16
Figure 16.1 Four main categories of additives are used to maximize the perform...
Chapter 17
Figure 17.1 Harmful effects of MiNaPs.
Figure 17.2 Impact of microplastics on the environment [30–34].
Figure 17.3 Adsorption of persistent organic contaminants on micro- and nanopl...
Figure 17.4 Aquatic environment affected by MiNaPs.
Figure 17.5 Ecosystem affected by MiNaPs.
Chapter 18
Figure 18.1 Advantages and disadvantages of nanotechnology [3]
.
Figure 18.2 Human exposure mechanism and risk evaluation of NPs [6].
Figure 18.3 Schematic representation of transfer of plastic litters in marine ...
Figure 18.4 Schematic representation of toxic effect of micro- and nanoplastic...
Chapter 19
Figure 19.1 Characterization, identification, and quantification methods for m...
Chapter 20
Figure 20.1 Annual plastic waste generation and management [15].
Figure 20.2 Possible exposure routes and adverse effects of micro- and nanopla...
Figure 20.3 Schematic of sources, sample collection, preparation, and micro- a...
Figure 20.4 Spectroscopic analysis of micro- and nanoplastics in different env...
Figure 20.5 Schematic of electroanalytical methods used for the analysis of mi...
Figure 20.6 Conventional and new advanced analytical approaches are used for m...
Chapter 22
Figure 22.1 Stages of the microplastic removal process by microorganisms.
Chapter 23
Figure 23.1 Magnetic biochar produced from olive pomace. (a) Olive pomace, (b)...
Figure 23.2 Different forms of activated carbon used as adsorbents.
Chapter 24
Figure 24.1 The exodus route of MPs in aquatic ecosystem.
Figure 24.2 Boundaries within MP/NP regulatory policies.
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Preface
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Toxic Effects of Micro- and Nanoplastics
Environment, Food and Human Health
Edited by
Inamuddin
Tariq Altalhi
and
Virgínia Cruz Fernandes
This edition first published 2024 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2024 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-394-23812-5
Cover image: Pixabay.ComCover design by Russell Richardson
Preface
Micro- and nanoplastics are the degradation products of large plastic compounds. These degraded polymers enter into the natural environment including air, water, and food, which leads to various significant threats to human health. The nature of these micro- and nanoplastics is persistent and consequently accumulates in the exposed person’s body. Research into microplastics has shown that these particles accumulate in various human organs and impart detrimental effects on humans. To safeguard human health, analysis and remediation strategies are necessary.
This book provides a comprehensive overview on the source, distribution, life cycle assessment strategies, physico-chemical interactions, methods of analysis, toxicological investigation, and remediation strategies of micro- and nanoplastics. It is an invaluable resource for academics, researchers, post-doctoral and Ph.D. students, the polymer industry, environment agencies, food and beverage professionals, etc.
Chapter 1 explains the effect of natural processes that microplastics undergo in the environment (e.g., radiation, physical abrasion, chemical reactions, and biodegradation), which causes an increase in their ability to adsorb other pollutants and transport them. The chapter also outlines the analytical techniques used to evaluate the chemical and physical changes.
Chapter 2 presents life cycle analysis and its stages as applied to new materials called “biobased,” which have emerged as an alternative to replace the use of plastics. The main focus of this chapter is to assess the environmental impacts of bioplastics versus petrochemical plastics and their sustainability.
Chapter 3 discusses micro- and nanoplastics as an invisible threat to human health. It reviews the various routes of exposure, the phenomenon of microplastics in nourishment and nutrients, and the impact of microplastics and nanoplastics on mammalian health and their effect on marine life.
Chapter 4 explains how the small plastic particles known as micro- and nanoplastics have become a significant environmental concern due to their widespread presence in various ecosystems. The toxic effects of these particles on the environment, food, and human health are a growing concern that requires more attention and action from governments, industries, and individuals. Reducing plastic waste and promoting the use of more sustainable alternatives can help mitigate this issue and protect our planet and health.
Chapter 5 discusses the probable sources of micro- and nanoplastics, and details their hazardous effects on different environments, including terrestrial, aqueous, atmosphere, wastewater treatment plants, and their resident organisms. It also explains the journey of these particles from their production source to their final destination.
Chapter 6 covers the routes through which micro- and nanoplastics can become part of our food and their possible toxic effects on human bodies and the food chain. Two primary ways that these plastic particles enter food products is through plastic food packaging or by being ingested by animals and absorbed into plants. This chapter explains how the side effects of MPs and NPs on human lives depend on numerous factors, such as plastic chemical functionality and biocompatibility, size, and amount of plastic ingested.
Chapter 7 discusses the microplastic, properties, types, and their impact on the environment in detail. Great attention is paid to various methods of eliminating microplastics. The chapter also includes goals and initiatives taken by the United Nations Sustainable Development Goal (SDG 14).
Chapter 8 analyzes the presence of micro- and nanoplastics in different types of beverages. It presents the classification of the analyzed beverages; the methods used for the quantification of micro- and nanoplastics; the characteristics of the particles; and their origin. Human exposure from the consumption of these products is also discussed.
Chapter 9 focuses on the effect of micro- and nanoplastics that end up in the terrestrial environment. It looks at their interaction with soil and plants while outlining their migration and accumulation inside the plant, and calculating their potential effect. The chapter also discusses the impact of micro- and nano plastics on terrestrial communities, including microbes and humans.
Chapter 10 addresses the presence of microplastics in personal care products (PCPs). The information is organized by three topics: the characterization of PM extracted from PCPs, their interactions with other substances, and toxicity. The chapter explains how the use of these products is alarming due to their wide use and risks to the environment.
Chapter 11 reveals how the various chemical compositions including plastics and microplastics are mixed into desired concentrations when manufacturing cosmetics. It discusses, too, the main sources of plastics and microplastics and their growth in India. The effect of cosmetics on human health is explained. Finally, alternative products to plastics and microplastics for use in cosmetics are listed.
Chapter 12 delves into the detrimental impact of micro- and nanoplastics on the human genome. The introduction of such particles into the ecosystem, and ultimately to the human body, is explained. This chapter presents an thorough toxicological analysis of these particles, shedding light on the urgent need for proactive measures to safeguard our ecosystem.
Chapter 13 discusses the generation, as well as the techniques for the measurement and identification, of micro- and nanoplastics. Various degradation methods are also discussed, as are the harmful effects of plastics, nanoplastics, and microplastics. Measures to avoid the production of plastics, nanoplastics, and microplastics are emphasized.
Chapter 14 details the source and hazardous effects of micro- and nanoplastics in marine environments. Additionally, it elaborates on the damages caused by the plastic pollution on air, water, and soil. Methods for decreasing microplastics in the environment are also discussed, along with the severance of microplastics from water, sediments, and marine microbial strains associated with degrading microplastics.
Chapter 15 reviews the advances and challenges in assessing the toxicity of micro- and nanoplastics (MPs and NPs) in human beings. An analysis of 85 research articles is also presented. Results show that in most cases there is a negative effect associated with MPs and NPs, but this chapter explains how methodology differences don’t allow the establishment of cause-effect relationships.
Chapter 16 delves into the extensive impact of plasticizers and flame retardants on ecosystems and human health. The presence of plasticizers and flame retardants in various environments raises concerns about potential ecotoxicological effects. This chapter explains how bridging knowledge gaps and promoting safer alternatives are crucial to address the risks posed by these additives.
Chapter 17 details the invisible threat of micro- and nanoplastic materials on mankind and the environment. It discusses the harmful effects of inorganic and organic contaminants that are present in MPs and NPs. Inorganic contaminants primarily include heavy metals and pesticides. However, organic contaminants are persistent organic pollutants, and the impact of persistent organic pollutants and inorganic contaminants on the environment are presented in detail.
Chapter 18 compares the toxicity of microplastics, nanoplastics, and nanoparticles in the ecosystems. Smaller particles can penetrate organisms and tissues leading to more severe impacts. Their unique properties increase reactivity and oxidative stress, raising concerns about bioaccumulation and higher trophic levels. This chapter explains why urgent mitigation strategies are needed to protect ecosystems from these pervasive pollutants.
Chapter 19 discusses the occurrence and sources of micro- and nanoplastics and the pretreatments performed in the samples. Additionally, it thoroughly discusses several techniques that can be used to characterize, identify, and quantify them. Furthermore, this chapter presents a general overview of the advantages, disadvantages, and limitations of those techniques.
Chapter 20 presents new analytical approaches for the analysis of micro- and nanoplastics in the environment. Microscopic, spectroscopic, thermal, and electroanalytical techniques are commonly used for the analysis of MPs and NPs. The chapter describes the development of analytical techniques for monitoring plastic pollution based on single and combined methods.
Chapter 21 details various enzymes that are applied for the biodegradation of micro- and nanoplastics. In this chapter, the advantages of enzymatic approaches compared to conventional methods are presented. The mechanism of enzyme-catalyzed degradation of plastics is also discussed, as are some examples from biodegradation of synthetic polymers that use various enzymes.
Chapter 22 explains how the most common physical, chemical, and biological techniques work to remove micro- and nanoplastics. Some of the most relevant findings found in the literature for each technique are presented, as are the advantages and disadvantages of each type of removal technique.
Chapter 23 details the different materials used to remove the micro- and nanoplastics from the water. This chapter explains how to use sponge/aerogel materials, materials with metals, and biochar to remove MPs and NPs. Also, remediation methods that employ powder and granulated activated carbons are presented.
Chapter 24 details the toxicity and aftereffects of micro- and nanoplastics on the marine environment and its flora and fauna. The providence of MPs and NPS and their migration to the aquatic environment, along with an analysis of various micro/nanoplastics toxicity and the propensity towards environmental implications, is also presented.
We are deeply grateful to everyone who helped with this book and greatly appreciate the dedicated support and valuable assistance rendered by Martin Scrivener and the Scrivener Publishing team during its publication.
The EditorsMarch 2024
1Aging Process of Microplastics in the Environment
Sílvia D. Martinho, Virgínia Cruz Fernandes*, Sónia A. Figueiredo† and Cristina Delerue-Matos
REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Porto, Portugal
Abstract
The presence of plastics in various ecosystems is an emerging worldwide environmental concern. Researchers have studied the interaction of microplastics (MPs) with other pollutants that are also present in the environment and have concluded that they act as vectors for pollution dispersion, transporting pollutants to different ecosystems, and being taken up by living organisms. The effects of natural processes that MPs undergo in the environment (UV radiation, physical abrasion, chemical reactions, and biodegradation) cause changes in their external surface, morphology, and chemical alterations that increase their ability to interact with other pollutants and transport them. Researchers have developed laboratory techniques to simulate the aging process of polymers and predict the behavior of MPs in real ecosystems. These reports highlight permanent physical and chemical changes in different properties of MPs, such as color, morphology, particle size, specific surface area, hydrophobicity, crystallinity, melting and glass transition temperature, surface groups, carbonyl index, and oxygen/carbon ratio. These properties have been measured using standard techniques (e.g., optical, fluorescence, and scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy); however, emerging techniques are being explored (two-dimensional correlation spectroscopy and excitation–emission matrix-parallel factor analysis), where it is possible to detect the release products of the aging process.
Keywords: Advanced oxidation process, aged microplastic, biodegradation, emerging contaminants, mechanical stress, photooxidation, pristine microplastic
1.1 Introduction
Plastics are widely used to meet various societal needs. Advantages such as light weight, low cost, and long durability have led to their expanded use and application in fields such as healthcare, engineering, construction, agriculture, and high-performance apparel [1–4]. The distribution of plastic use in industries is estimated to be 4% is used in the electrical and electronics industry and construction, 6% for transportation, 12% for consumer and institutional products, 14% for textiles, 13% for other industries, and 43% for packing [5]. Apart from their applicability, their production can also have a great impact on the environment, as they can be manufactured with fossil fuels, which have a great impact on the carbon footprint, or with natural materials, such as cellulose [2, 3]. Biobased plastics have been researched in recent years and have proven to be an alternative to fossil plastics, as they are largely derived from biomass. However, they currently account for only 1%–2% of the annual production of plastics. Nevertheless, a study of the cradle-to-grave life cycle of biobased plastic should be conducted to balance the use of fossil versus biobased plastic [6, 7]. Despite these new alternatives, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS) are the most commonly used polymers that are produced from fossil hydrocarbons [3, 8–10].
Plastics are adaptable and inexpensive, and plastic production between 2005 and 2017 was as high as in the last 50 years, showing a tendency to increase exponentially, posing a problem in the treatment and disposal of plastic waste [1]. In 2016, the entrance of 19 to 23 million t of plastics into the aquatic environment was estimated and it is predicted that 20–53 Mt/year will be released into aquatic systems by 2030 [11]. Researchers expect that double plastic production would be achieved by 2050, meaning that approximately 8 million tons of plastic waste will escape into the oceans [12]. Single-use plastics, such as bags and straws, represent approximately half of the plastic waste generated. During the COVID-19 pandemic, protective gear containing plastics (e.g., gloves and face masks) is often used by the population, increasing the amount of plastic waste [1, 12, 13]. Zhao et al. reported that 6,300 million tons of plastic waste was generated in 2015, of which only 9% was recycled, 12% was incinerated, and 79% was disposed of in landfills [2]. According to Williams et al., of the plastic waste generated since 1950, 14% is incinerated, 40% is sent to landfills, and 14% is recycled. However, of this amount of recycled plastic only, 2% is optimally recycled, and the remaining 12% produces material with lower quality and functionality than the original, which is referred to as “downcycle” [12].
Based on this information and knowledge of the long life of plastics, humanity may face a worrying environmental problem in the coming years [14]. Governments around the world have introduced regulations to reduce the use of single-use plastics, namely imposing taxes on plastic bags and food packaging [1]. The incorrect disposal of plastics is a major problem of pollution, which may cause their entrance into the oceans [12, 15]. In recent years, researchers have explored plastic pollution from manufacture to final disposal, and the damage caused by plastic to ecosystems, but there is still a long way to go to understand how harmful their chronic presence may be to the environment.
MPs may have two types of sources: the primary source, which is considered a direct contributor, focused on the manufacturing of MPs in various industries, such as exfoliating cleansers, cosmetics, and toothpaste [14, 16]; and the secondary source, which is considered an indirect contributor to MPs, caused by the fragmentation of large plastic pieces into small ones, which can be promoted by photodegradation, mechanical or chemical action, or other weathering processes to which plastics are subjected to improper disposal in the environment [9, 16, 17].
Plastics are subjected to physical, chemical, and biological reactions over time, resulting in the desorption of smaller particles [8, 18]. Plastics can be classified based on their size as megaplastics (>50 cm), macroplastics (>5 to 50 cm), mesoplastics (≥5 mm to 5 cm), microplastics (≥1 μm to <5 mm), and nanoplastics (<1 μm) [14, 18, 19]. MPs have become the focus of research in recent years owing to their widespread presence in ecosystems, which is considered a threat to the environment, and consequently to human health. Microplastics (MPs) have been identified in freshwater [8, 10, 14, 16, 17, 20, 21], groundwater [8, 17, 20], snow [17], ice [17], sediments [8, 16, 17, 21, 22], soils [10, 17, 22–24], terrestrial and aquatic biota [10, 14, 24], air [17, 22, 25], foodstuffs (e.g., honey and salt), tap/bottled water [17, 22, 26], and biological samples (e.g., blood, human placenta, lung tissue) [27–29]. The ubiquity of MPs in the environment and their presence in consumer products, such as food or freshwater, leads to unrestrained consumption of MPs by humans [17]. Ingestion through direct consumption of contaminated products, inhalation of airborne contaminants with inhalable sizes of MPs and dermal contact between nanoplastics and the skin barrier are considered human exposure to MPs [22].
The biggest problem arises when researchers discover the ability of MPs to adsorb and transport various types of pollutants [9, 14, 23, 30–32]. Reports have shown that pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), heavy metals, pesticides and antibiotics can be transported by MPs [10, 20, 30, 33–35]. Moreover, ecotoxicity studies show the hazardous effects of MPs taken up by earthworms, mussels, gobies, seabirds, turtles, seals, mammals, fish, reptiles, and plants [8, 14, 23, 36]. Depending on their exposure and susceptibility to MPs, they are considered potentially harmful to humans because of their high surface area, which can provoke cytotoxicity, oxidative stress, and translocation to other tissues [17, 22, 37]. Their persistence may also cause chronic inflammation with possible carcinogenic effects and immune or neurodegenerative diseases [22]. Recent studies have reported that MPs have been detected in human placenta, blood, and lung tissue [27–29], increasing the urgency to understand the behavior of MPs, including their interactions, and find solutions to minimize their impact on ecosystems, organisms, and human health.
Reducing plastic use is crucial to minimize this problem. Resolutions are being made regarding single-use plastics, and some countries have defined laws banning certain types of plastics. Resolutions such as taxing the production of single-use plastic (SUP) bags, charging for the use of SUP bags, assigning recycling targets to the manufacturer, and more radically, countries such as Jakarta have already banned the use of SUP bags completely, requiring the use of environmentally friendly bags [38]. The use of biodegradable plastics contributes to solving the plastic waste problem; however, suitable microorganisms must be present to ensure their degradation; otherwise, we will only address the problem [4]. It is crucial to harmonize policies, invest in alternative materials, and improve research on MPs, particularly in terms of ecotoxicity, namely the chronic effects on human life, which are still unknown. In addition, the focus should be on the pathways and interactions to find future solutions to minimize the impact of this problem.
1.2 Impact of MPs on the Environment
Recent studies have focused on the effects of MPs on the ecosystems where they are spread (air, terrestrial, and aquatic). As physical–chemical properties change due to the natural aging process, researchers have driven their studies on the behavior and ability of MPs to transport pollutants (e.g., PAHs, PCBs, pesticides, etc.) [10, 20, 30, 33, 34]. Adsorption and absorption constitute the sorption process and consist of the transfer of chemicals from liquids or gases to a solid, in this case MPs [39, 40]. The transfer of contaminants occurs due to interactions (van der Waals, ionic and steric forces, л–л interactions, and covalent bonds) with the surface of MPs, which is considered an adsorption process [39, 40]. Strong interactions between a low pollutant concentration and the surface of the adsorbent lead to adsorption. However, if the contaminant concentration is high, absorption occurs as soon as a large volume of pores is available to settle the pollutant molecules [39, 40]. Characteristics such as composition, size, shape, density, and chemical composition of MPs are key factors that promote the adsorption of MPs [40, 41], which may be changed by the aging processes that occur in MPs. However, environmental conditions (e.g., pH, temperature, salinity, and ionic strength) can also influence the adsorption process [42].
Studies have been carried out to predict the impact of the presence of MPs in different organisms, from aquatic (e.g., crabs and fish) to terrestrial (e.g., earthworms, nematodes, and mites) organisms. Although the responses differ according to the test organism, researchers have shown that MPs can cause hazardous effects (e.g., oxidative stress, cytotoxicity, and translocation to other tissues). Long-term contact and constant ingestion of MPs by organisms such as fish may cause effects along the food chain, leading to chronic inflammation (e.g., of the lungs) and increased risk of cancer, immune or neurodegenerative diseases, and metabolic disorders in humans [8, 22, 43, 44]. Furthermore, the harmful effects of MPs on other living organisms (plants and soil invertebrates) are of great concern [36].
Lei et al. investigated the effects of PS (diameter between 100 and 500 nm) on the survival rate, lifespan, motor behavior, movement-related neurons, and oxidative stress in Caenorhabditis elegans. After 3 days of contact, a decrease in the rate of survival, a large decrease in the organism length, and a decrease in the average life span of the nematodes were observed. In this study, it was also found that MPs can cause oxidative damage in nematodes, and the size of the particles affects their toxicity, which has far-reaching effects [43].
HDPE particles can transport chlorpyrifos (CPF), a commonly used pesticide. When this combination is in contact with mussels for 21 days, changes in the biological responses can be observed, which are greater than those induced by any stressor individually, according to the study by Fernándes et al. [31].
In a study performed by Bessa et al., 157 particles of MPs were detected, corresponding to 38 % of all fish, with 1.67 ± 0.27 (SD) MPs per fish, in three commercial fish species: sea bass (Dicentrarchus labrax), sea bream (Diplodus vulgaris), and flounder (Platichthys flesus). In addition, ecotoxicological studies need to be conducted to understand the risks to fish health and the consequences of consuming these fish in humans [20]. According to a review by Rakib et al., approximately 25 studies have reported various effects of MPs on different marine organisms, including ingestion, translocation, and respective impacts, reduction of the feed, oxidative stress or retention in the digestive tract, or even mortality of species [45].
1.3 Pristine and Aged Microplastics
MPs are widespread in the atmosphere and in terrestrial and aquatic systems. After their release, they are subjected to natural phenomena that lead to aging [46]. Ultraviolet (UV) radiation, physical abrasion, chemical oxidation, and biodegradation cause physical and chemical changes to the MPs [46, 47]. Exposure to UV radiation, known as photooxidation, leads to rapid degradation of the polymer in the environment, resulting in color changes and the appearance of cracks [48]. Although UV radiation is considered the main cause of aging of MPs, it is important to consider other phenomena that may play a role, such as mechanical stress or physical abrasion. Waves, tides, gravel, sand, stone, water flow, and other particles surrounding MPs can affect their physical properties and render them brittle. This aging process can result in changes in crystallinity, thermal hydrophilicity, and degree of polymerization [46, 49]. Chemical reactions may also occur, promoted by reactive oxygen species (ROS) [50, 51]. Photooxidation may occur because of a chemical reaction between MPs and ROS produced from natural organic matter (NOM), NO−3, and CO2−3. In addition, after exposure to sunlight, pigments can produce ROS through a series of reactions that can oxidize the polymer [50–52]. Weathering phenomena, such as UV light, mechanical erosion, or chemical reactions, can play an important role in the life cycle of MP, as they cause changes in polymer properties.
The use of their aged in a natural environment was the better choice to study their interactions, but uncontrollable factors were associated with it. Therefore, researchers have focused on simulating the aging process in the natural environment of the laboratory, which although being more controlled may be less realistic. With constant changes in the environment and the emergence of new pollutants and possible new interactions, researchers have also focused on simulating environmental phenomena at the laboratory scale, such as photooxidation, mechanical stress, and chemical oxidation [53]. The development of these laboratory-scale aging tests is important for predicting and determining the behavior of aged MPs compared to pristine MPs, as the process of aging is very slow in the real environment [53]. According to Liu et al., researchers are focusing on selecting the best laboratory technologies to increase the speed of the MP aging process. The most commonly used technology is light irradiation (66.7%), followed by chemical oxidation (16.7%), heat treatment, and microbial degradation (less than 26.6%) [52]. Despite the difficulty of the developed aging techniques, researchers have focused on understanding the significant changes in MPs after the aging process: physical changes, such as color changes, cracks on the surface of MP, or chemical changes, such as the differences between spectra from the Fourier-transform infrared spectroscopy (FTIR) and Raman analysis, or even changes in crystallinity, such as an increase in melting temperature. Table 1.1 summarizes the significant changes found in MPs after the aging process in the laboratory, with different changes showing the effects of aging processes. Understanding the behavior of MPs and their interactions can be complex, considering that mechanical agents, chemical, and biological reactions constantly occur in the environment. The change in properties has a significant impact on the adsorption behavior of MPs [54–57].
Adsorption studies were conducted with a focus on comparing the behavior of MPs in the pristine and aged states to understand the influence of altered properties. Zhang et al. studied the adsorption process of oxytetracycline in PS using purchased PS foams and aged PS foams made from plastic waste collected from coastal beaches. The influence of pH (between 2.0 and 10.0) and ionic strength (using sodium chloride, calcium chloride, and sodium sulfate) was tested to understand the effect on the adsorption process. The maximum adsorption capacity was observed at pH 5 for the beached PS samples, and stronger sorption of oxytetracycline in the MPs was observed in the presence of CaCl2. Based on the equilibrium isotherms, it was found that aged PS had a higher adsorption capacity than pristine PS (1,520 μg g−1 and 27,500 μg g−1, respectively) [58]. Fan et al. simulated the aging behavior of PS and polylactic acid (PLA) in a natural environment, exposing the MPs in a UV radiation experiment, to compare the behavior of the pristine MPs in the adsorption process of tetracycline (TC). Aged PS and PLA presented a higher adsorption capacity for these antibiotics (e.g., 5.21 mg g−1 and 5.49 mg g−1, respectively), showing that the change of surface structure observed for the aged MPs favors the adsorption process. Compared to those of pristine PS and PLA, the adsorption capacity obtained was 2.75 mg g−1 and 2.51 mg g−1, respectively [54]. Studies on the adsorption capacity of heavy metals in MPs showed that aged MPs presented a higher capacity than pristine MPs, as shown in the study conducted by Mao et al. PS was subjected to three types of aging processes in the laboratory and showed an increase in adsorption capacity in air, seawater, and pure water for five heavy metal ions (Pb2+, Cu2+, Cd2+, Ni2+, and Zn2+) [56]. These studies demonstrated that pollutants could be adsorbed by different types of MPs, and, an increase in the adsorption capacity was observed after aging.
Table 1.1 Physical and chemical changes of MPs after suffering an aging process.
Property
Agent
Changes
References
Color
Photooxidation
Yellow, opacity
[
49
,
64
,
66
,
95
–
98
]
Morphology
PhotooxidationAOPMechanical stressBiodegradation
Cracks, flakes, roughness, biofilm colonization
[
56
,
66
,
95
–
97
,
99
–
104
]
Particle size
PhotooxidationAOPMechanical stressBiodegradation
Decrease
[
49
,
59
,
86
,
88
,
89
,
98
]
SSA
Photooxidation AOP
Increase
[
33
,
53
–
55
,
58
,
67
,
84
,
105
]
Contact angle
PhotooxidationAOP
Decrease
[
77
,
99
,
100
,
105
,
106
]
Crystallinity
PhotooxidationAOP
IncreaseDecrease
[
33
,
56
,
74
][
75
,
100
,
107
]
Melting temperature
Photooxidation
Increase/Decrease
[
59
,
100
,
103
,
108
]
Glass transition temperature
Photooxidation
Changeable
[
59
,
108
–
111
]
Surface groups
PhotooxidationAOPMechanical stressBiodegradation
New peak/band formation
[
67
,
78
,
79
,
95
,
103
,
112
,
113
]
CI
PhotooxidationAOPMechanical stressBiodegradation
Increase
[
50
,
92
,
100
,
101
,
106
,
107
]
O/C
PhotooxidationAOPMechanical stressBiodegradation
Increase
[
53
,
56
,
84
,
90
,
98
,
99
,
106
]
Adsorption capacity
PhotooxidationAOPMechanical stressBiodegradation
Increase
[
47
,
96
,
101
,
102
,
106
,
114
,
115
]
Environmental concerns arise because all MPs spread in ecosystems constantly change under UV radiation, mechanical stress, chemical reactions, and contact with multiple contaminants. It is important to understand the pathways of MPs in the environment, their infinite interactions, and their awareness of environmental conditions.
1.4 Influence of Aging Processes in the Properties of MPs
Physical, chemical, and biological processes lead to aging, which is due to changes in size, physical resistance, surface area, thermal stability, and chemical composition. Focusing on the changes in these properties will provide a closer look at the real environment and allow researchers to understand the different stages of aging that MPs undergo.
1.4.1 Physical Properties
MPs are exposed to physical abrasion through contact with sand and rocks, and when taken up by waves and wind [14, 48]. Their particle size constantly changes due to either fragmentation promoted by mechanical stress or photooxidation, which breaks some bonds in the MPs structure [49, 59]. Researchers are exploring the changes in physical properties, such as density, shape, color, specific surface area (SSA), and particle diameter, which decrease owing to the fragmentation/degradation of plastics [60].
The density of MPs changes over time and may play an important role in their behavior. Density gradient solutions can be used to determine the density of MPs by observing the floating or sinking state in density gradient solutions [61]. MPs have a density closer to water (0.8 to 1.4 g cm−3), so the use of salt solutions, such as sodium chloride, sodium iodine, and zinc chloride, separates the MPs from other compounds [62, 63]. When the density is higher than that of water, MPs sink and settle with the sediments, while at a low density, they float [9].
Another characteristic whose changes can be identified is the color of the MPs, which usually changes after aging and can be easily identified visually or microscopically [64]. The color change is caused by the formation of chromogenic groups on the surface of the particles, as Bandow et al. observed on PVC particles when they were subjected to an aging process (8 weeks with UV radiation exposure of 190 MJ m−2) and the particles turned yellow. This color change was the result of the formation of polyenes, and when the polyenes had more than eight C=C‒C bonds, the absorption in the visible range decreased, resulting in a yellow color [64]. This change can increase the attention of organisms, as some of them are visual predators, such as goby fish, thereby increasing the probability of ingestion [53].
The SSA is also an important physical property that is directly affected by the aging process, as it is related to the structural change of the particle [52, 65]. This property can be determined from the Brunauer–Emmett–Teller (BET) equilibrium isotherm using a nitrogen physisorption analyzer. Studies have examined the correlation between the aging process and SSA and concluded that the smaller the particle size, the larger the BET SSA [52, 66, 67].
Optical microscopy, fluorescence microscopy, and scanning electron microscopy (SEM) can be used to record the classification and abundance of large MPs with characteristic colors and morphologies [62]. The transport of MPs can be affected by the size and shape (e.g., fibers, pellets, filaments, fragments, films, foams, microbeads, and granules) of MPs [18, 37, 68]. These two characteristics may also affect adsorption because particles with a high area-to-volume ratio (smaller sizes and irregular shapes) have a high adsorption capacity for other pollutants, thereby enhancing their hazardous potential [69]. Different studies have used SEM to observe the impact of the aging process on the surface of particles. Gao et al. tested different MPs (PA, PET, PS, and PVC) in four environmental media (air, seawater, sand, and soil) under UV irradiation for three months. When the particles were observed with SEM, the entire surface of the MPs changed, presenting cracks, bulges, wrinkles, oxidized particles, and pores, making the MP particles susceptible to embrittlement and disintegration [46, 47, 49, 66].
Another study reported that PE exposed to UV irradiation for 6 weeks, at controlled temperature, humidity, and light irradiation, showed a surface with cracks and a significant enlargement of the surface in the SEM analysis [66]. Despite the advantages of identifying changes on the surface of MPs, it is important to be aware of the limitations of visual identification methods because they can be influenced by the observer [62, 70, 71].
1.4.2 Chemical Properties
In addition to physical changes, MPs are subject to chemical changes that modify their crystallinity, thermal stability, and surface functional groups [72]. Polymers can be characterized according to their degree of crystallinity, which depends on the complexity of the polymer, chain configuration, and isomerism. Aging studies have shown that the crystallinity of MPs can increase owing to the degradation of amorphous polymers and chain scission reactions, suggesting that this parameter can be useful as an indicator of chain scission [59, 73]. Wang et al. focused their study on the adsorption capacity of PS and PE of atrazine, distinguishing between pristine and aged MPs in a UV-irradiated chamber in the laboratory for 96 h. The two MPs suffered an increase in crystallinity from 39% and 41% to 46% and 44% for the aged PS and PE, respectively, which promoted an increase in the adsorption capacity [33]. An increase in the crystallinity of PP and PS of approximately 50% was also observed after 4 weeks of UV irradiation at 60 °C [74]. However, an increase in crystallinity was not observed in any of the aging processes. Wu et al. observed a decrease in the crystallinity of aged PP (oxidation process with heat-activated potassium persulfate) from 56% to 49% [75]. Crystallinity changes with the aging process, depending on the composition and method of aging of the MP.
The hydrophobicity of a polymer is related to the water contact angle, which means that a larger contact angle will lead to stronger hydrophobicity [76]. Wang et al
