Handbook of Microplastics in the Environment

Ubiquitous and highly pervasive microplastics have been found in all compartments of the environment. However, correctly assessing their prevalence is greatly hampered by the current methodological and technical limitations, as well as data reporting and analysis. Herein, we discuss the most pressing issues associated with the analysis of microplastics in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification. Furthermore, the need for analytical quality control and quality assurance associated with the validation of analytical methods, including the use of reference materials for the quantification of microplastics, is also examined. Lastly, the current challenges within this field of research and foreseeable routes to overcome such limitations are discussed.

Highly ubiquitous, microplastics are found throughout all spheres of the environment. However, their exact prevalence and mechanisms of distribution remain largely unknown and inaccurate, as standardized sampling and monitoring methods are needed. Multiple methods for sampling and separating microplastics from different environmental matrices exist, but the lack of such standardized methodologies significantly impairs data comparison and subsequent toxicological assessments, rendering the gathered data of limited utility.Herein, these methods are overviewed, and the associated advantages and limitations are discussed, as well as some of the most prevailing limitations in the currently available scientific literature. Lastly, some of the strategies to assess the quality of the gathered data are suggested, as well as methodological steps that may expressively contribute to generate better, susceptible to comparison, data.

Microplastics are threatening materials directly produced by anthropogenic activities or resulting products of macroplastic degradation. Extended scientific research is being carried out on micro-/nanoplastics due to their relentless and increasing presence in the marine ecosystem with unpredicted ecological consequences. Thus, assessment of origin, life cycle, chemical nature, or composition of such polymer-based materials is essential and extremely valuable.The application of optical and electron (SEM/EDS) microscopy on the analysis and characterization of micro-/nanoplastics in aquatic environment is described in this chapter. It focuses on the benefits of using optical and electron imaging techniques for the detection and characterization of microplastics. Currently, these advanced imaging and analytical techniques have been essential in the categorization of such pollutants and other toxic substances that may be adsorbed at their surface. The emerging importance of SEM/EDS in the identification of microplastic-associated pollutants such as toxic metals is addressed. Suggestions for appropriate sample preparation and observation of these micromaterials under a microscope are briefly discussed.This chapter also highlights the importance of combining optical microscopy with spectroscopic techniques such as infrared and Raman scattering since it further enables precise chemical identification and analysis of microplastics.Ultimately, the collective use of SEM/EDS and optical microscopy associated with the spectroscopic analytical tools results in the most powerful strategy for accurate microplastic analysis.

A realistic risk assessment of microplastic pollution must stand on representative data on the abundance, size distribution, and chemical composition of polymers. Infrared spectroscopy is an indispensable tool for the analysis of microplastics (<5 mm). Spectral imaging, which provides simultaneous measurement of spatial (e.g., particle morphology) and spectroscopic information, is a promising approach toward automated microplastic analysis. This chapter aims at providing guidelines to assist with the analysis of spectral imaging data and summarizing the limitations and analytical challenges from a technical point of view. Topics, like automated particle selection for faster infrared mapping, spectral pre-processing to enhance signal quality, multivariate exploratory analysis, comprehensive reference spectral libraries, spectral matching approaches, and model-based classification, will be exposed and some possible strategies and solutions given and discussed. We will demonstrate how to identify microplastic species by using Fourier transform infrared spectroscopy data in a stepwise manner, with detailed MATLAB command line scripts freely available to be downloaded. The reader is guided through every step and oriented in order to adapt those strategies to the user’s individual case.

Identification and quantification of microplastics in the environment is increasingly important. With decreasing particle size, microplastic numbers and therewith the number of species potentially affected by microplastics rise. However, data on the occurrence of small microplastics (<20 μm) in the environment are scarce. Raman microscopy represents an important analytical tool, providing the possibility to close this niche of determining the smallest microplastics. Data on microplastic numbers, their size, shape, and polymer types can be gained. This chapter gives an overview on established applications of Raman microscopy and an outlook on potentially useful future techniques for microplastic analysis. As a basis, the theoretical, physical background of the Raman effect, absorption of infrared light, and the formation of fluorescence is explained. Advantages and disadvantages of Raman microscopy for the detection of microplastics are displayed. Further, all the important methodological steps are discussed: sample preparation to separate microplastics from matrices and to reduce interferences during Raman measurement; the choice of an adequate Raman substrate to achieve good visibility of particles and high quality Raman spectra; measurement parameters and their impact on the results; different measurement modes, such as manual and automatic single particle measurement and Raman mapping, as well as their advantages and disadvantages; prerequisites for representative analysis; and tools for spectral and data interpretation.

By now the polymeric nature of microparticles has to be demonstrated before their classification as microplastics. Pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) has been used for years to characterize polymers. Thanks to three distinct steps, destructuring, separation, and identification, this chapter explains how this technique allows the analyst to ascertain the polymeric composition of different plastic materials and much more. Far from being used as much as vibrational spectroscopy methods for the study of microplastics, Py-GC/MS nevertheless has advantages which will be presented in this chapter, through the presentation of the contributions of this technique in terms of identification and quantification of microplastics. All of the studies presented here allow to outline some good laboratory practices relative to this technique. The last part of this chapter is dedicated to the future of microplastics analysis by Py-GC/MS, including the need of method normalization and the contribution of this technology for the research of nanoplastics and additives.

The atmosphere is populated by different types of particles, including those of synthetic origin. Originating from products and activities, such as textiles and tire abrasion, microplastics and microfibers are released into the indoor and outdoor air. In the environment, these airborne microplastics and microfibers are released, transported by the wind, deposited, and resuspended, crossing boundaries between environmental compartments in a dynamic exchange. Eventually, they find their way into our respiratory systems where, in high concentrations, they may cause chronic inflammatory lesions. The presence of synthetic particles in the atmosphere has been detected in 14 studies, with varying methodological approaches for the sampling of suspended or deposited particles. For suspended particles, concentrations range from 0.4 to 59.4 for indoor and from 0 to 1.5 particles m−3 for outdoor air. In deposition studies conducted outdoors, concentrations range from 1,600 to 11,000 particles m−2 d−1. Even though there are only 14 studies, the number of current methodologies for sampling is already varied and each group uses their own version of sampling and processing protocols. Such a diversity in methodologies greatly limits the interpretation of results. But can these current concentrations of airborne synthetic particles have an impact in our world? In terms of health, limited negative consequences are expected from environmental exposure. Even occupational exposure only results in respiratory lesions when workers are exposed to high concentrations usually resulting from the lack of protection measures, such as proper ventilation. However, environmental contamination caused by deposition of airborne synthetic particles may cause severe consequences, not necessarily expected at the level of organism toxicity, but by altering the physical properties of matrices which may cause irreversible changes to essential Earth systems. Thus, better understanding of concentrations, characteristics, and distribution of airborne microplastics and microfibers is needed to provide grounds for prevention and mitigation measures.

The massive scope of plastic and microplastic pollution in soils and sediments requires broad and thorough studies to understand details of the extent and effects of these persistent pollutants. Plastic particulate pollutants in the environment are subjected to natural processes, fragment over time into smaller pieces, and influence the surrounding biota. Land environments, from open fields to agricultural fields to watersheds and deep ocean sediment, have been subjected to plastics/microplastics from a variety of sources and via natural and anthropogenic transport for many years. A number of different sampling, processing, and detection methods have been used to identify and quantify the loads of microplastics in soils and sediments. Scientific studies are still lacking systematic, standardized protocols, which will allow for accurate comparisons and compilations of data from around the world. This review chapter highlights many studies published over the past several years on land environments affected by microplastics. The chapter also summarizes the most common experimental methodologies and the studies on the known and potential effects on certain microoganisms and the microbiome. More studies, guided by standardized procedures, are required to better understand the scope of microplastic pollution in the terrestrial environments in the midst of rising plastic manufacturing. The numerous studies of microplastic pollution on living systems are concerning, showing substantial direct and indirect influences on function, growth, and gene transfer.

Microplastics have been found in nearly all types of freshwater environments, including remote lakes and rivers. Although all types of microplastics have been reported in freshwater ecosystems, microfibers are typically the most common microplastic type, often accounting for more than 80% of all the plastic fragments recovered. Understanding of the sources, movement, and fate of microplastics in freshwater ecosystems is still an active area of research; however, wastewater treatment plants and stormwater runoff appear to be important conduits of microplastics to lakes and rivers. More research is required to determine the role of atmospheric fallout in loading microplastics to freshwater ecosystems. Field and laboratory techniques for sampling microplastics in freshwater environments closely follow protocols for marine systems, although the lower density of freshwater compared to salt water can alter results if certain plastic polymers sink in freshwater compared to salt water. Further research is required to increase our understanding of the sources, movement, and fate of microplastic in aquatic ecosystems and the potential impacts of microplastics on freshwater organisms. This research will greatly increase our understanding of the role of freshwaters in the global plastic cycle.

After several investigations on plastic pollution in marine environments, the issue was raised in continental environments, mainly rivers. The latter was extensively studied as a potentially significant source of marine plastic debris. However, the estuaries represent a transition environment between continental and marine areas, making it a critical interface. Only limited studies were conducted on these environments that present the extra-complexity of being under the influence of variable and poorly understood dynamics. For instance, tidal cycles, salinity gradient, and maximum turbidity front are all estuarine characteristics that need to be considered when studying such an environment. The present review evaluates the current state of knowledge and assesses the way different studies deal with the estuarine specificities. It discusses the dynamics underwent by the plastic debris in estuaries. Ultimately, the question of the role of the estuaries, either as sources or sinks of plastic pollution, is raised.

Microplastics are increasingly recognized as being globally widespread, but relatively little is known about the presence and abundance of microplastics in samples collected in Polar Regions. Here we review the current knowledge about microplastic occurrence and distribution in polar environments, with a particular focus on the relevance of the data and comparability between Arctic and Antarctic investigations. In the Arctic, microplastics have been found in seawater, marine sediments, ice, and snow and in the gut content of several species at different trophic levels. Antarctica is still, by far, the least affected region by human activity than anywhere else in the world, and the few studies carried out in this region find microplastics at very low concentrations. Studies focusing on microplastic threats to key species of Arctic and Antarctic marine food webs are urgently needed as are coordinated long-term studies on microplastic pollution, which are mandatory to follow the temporal trend of human impact in these remote regions.

Microplastics (MPs) are unregulated and emerging contaminants, which are continuously released due to human activities in the environment through several pathways. The presence of MPs poses threats to the environment, organisms, and human health. The discharge of treated effluent from wastewater treatment plants (WWTPs) is a major source of MP input, especially in the form of microfibers, into the aquatic environment, whereas the application of sludge and compost is a crucial pathway transferring MPs to terrestrial environment. Meanwhile, MPs are produced from industrial processes and the use of plastic consumer goods and personal care products. MPs become more hazardous when they adsorb persistent organic pollutants and heavy metals or attach with pathogenic microorganisms from wastewater and sludge. However, there is little comprehensive information available about the collaborative role of wastewater and sludge in MP contamination. Studies about remediation strategies and their removal mechanisms of MPs in WWTPs are limited. Therefore, it is important to develop cost-effective detection methods of MPs for routine monitoring in wastewater and sludge samples and understanding of fate and inhibitory effects of MPs in wastewater and sludge treatment processes, before developing the mitigation measures of MP contamination. This chapter summarizes the sources and pathways of MPs, discusses the impacts of MPs on environment and human health, and reviews the current practices on detection, quantification, and qualification of MPs. In addition, this chapter provides insights into the source control of MPs through polices and education.

Microplastics are omnipresent and pose a global threat to the environment due to their robustness, resilience, and enduring existence. Most of the microplastics research to date has focused on the marine ecosystem. Although freshwater and terrestrial ecosystem is perceived as starting points and transport pathways of plastics to the seas, there is a scarcity of information about these ecological compartments for effective ecological risk assessment. On reaching the environment, due to lower densities than water, MPs are subject to transportation through strong winds and river streams. This makes aggregation in various ecological compartments possible over some time due to their small size and large surface area. Existing scientific evidence shows that exposure to microplastics causes a wide range of toxic insults from feeding disruption to reproductive efficiency, physical adsorption, energy metabolism disruption, changes in liver physiology, synergistic, and antagonistic activity of certain organic compounds, among others, from producers to consumer trophic level. The objective of this chapter is to provide information on pertinent adverse effects of MPs in freshwater, marine water, and soil compartments from lower to the higher biological level of organization.

This chapter presents a compilation of the analytical techniques used to detect and analyze microplastics in food. A detailed description of microplastics found in different samples is provided as well as an estimate of the annual intake of these particles. A total of 22–37 milligrams of microplastics per year was found. The factors that can influence the presence of particles in food, especially table salt, are discussed, showing that a background presence of microplastics in the environment can explain a large amount of experimental data.

Microplastics (MPs) are recognized as emergent contaminants in both terrestrial and aquatic environments due to their ability to absorb and release toxic chemicals. The complex interactions that occur between synthetic MPs polymers and hydrophobic toxic compounds, metals, additives, and other emergent contaminants complicates the standardization of techniques used for the extraction and quantitation of these chemicals. Organic compounds are extracted from MPs by soaking, sonication, and the use of microwave, Soxhlet and accelerated solvent extraction (ASE) techniques in a variety of polar and nonpolar solvents. The extracts are cleaned up through solid-phase extraction (SPE) and analyzed by gas chromatography (GC) or liquid chromatography (LC) using an assortment of detectors. The analysis of metals from MPs is more standardized, usually with extraction in 20% aqua regia and analysis by inductively coupled plasma mass spectrophotometry (ICP-MS). Published papers do not consistently report the use of standards, detection levels, and other quality control measures. This chapter provides a summary of research on the chemical analysis of toxic compounds sorbed to and leached from MPs in order to better understand the chemical processes and help advance the harmonization of chemical analysis of MPs and their associated contaminants.

The potential of plastic debris to serve as alternative substrates for various biota have gained interest in recent years. In particular, studies on microbial colonization revealed their impacts and roles on the fate and potential risks of the plastic material, giving rise to the field of “plastisphere” research. These microbes have been shown to change the buoyancy of the material and promote sinking, increase the dispersal of attaching species, facilitate ingestion by changing its chemosensory properties, enhance biodeterioration and biodegradation, and even influence local biogeochemical cycles and ecological functions. Thus, exploring plastic-associated communities is important in helping us understand the full extent of the ecological impacts of plastics and microplastics pollution. However, the era of plastisphere research has just started to take off and many aspects of its “ecology” are yet to be explored, which also translates to more opportunities for researchers. This chapter focuses on the implications of microbial colonization of the plastics surface and the challenges in studying this unique association. Specifically, we assess the common themes in plastisphere research and summarize the current methods, from sample collection to analysis, that have been commonly employed in studying these communities. Although great advances have been made, standardization of protocols for future work might still be needed to enable more informative and meaningful comparisons among plastisphere studies.

A wide range of techniques are available for micro(nano)plastics recovery and identification in the marine environment and in soils. The identification of chemical composition of micro(nano)plastics allows for a clear assignment of a sample to a certain polymer/copolymer origin. For the identification of the polymers/copolymers there are techniques that combine microscopic and spectroscopic analyses and techniques based on thermoanalytical – mass spectrometry coupling. Some of the identification methodologies are simple and cost-effective methods (e.g., FTIR and visual inspection), but not easily applicable on the smallest microplastics. Staining of microplastics has found a quite common use in the detection of many polymers. For the identification of micro(nano)plastics the techniques of Fourier-transform infrared (FTIR) spectroscopy and the Raman spectroscopy are most commonly used. Using these spectroscopic techniques, a reliable and fast analysis of polymer debris from environmental samples is possible. The destructive thermoanalytical methods combined with mass spectrometry, such as pyrolysis – gas chromatography/mass spectrometry (Py-GC/MS), pyrolysis-mass spectrometry (Py-MS), thermal extraction-desorption gas chromatography/mass spectrometry (TED-GC/MS), headspace solid-phase microextraction – gas chromatography/mass spectrometry (HS SPME – GC/MS) or thermogravimetric analysis, coupled to mass spectrometry (TGA-MS) or to the Fourier-transform infrared spectroscopy (TG-FTIR), have the ability to analyze the polymer/copolymer particles in complex environmental matrices without any pretreatment; the information on particle numbers and size is not obtained. These measurement techniques are very time-consuming, expensive, and need qualified personnel.In this book chapter, the challenges in the analysis of micro(nano)plastics such as sampling, separation and identification are discussed.

The accumulation of microplastics in the environment and especially in the aquatic ecosystems because of human activity is a problem of high ecological importance. Combined effort is required to deal with it due to its special characteristics.The degradation of plastic items,Degradation, plastic items i.e., the conversion of plastics into smaller molecules in the environment can occur through a variety of physicochemical and biochemical processes. Plastics present high durability and therefore low degradation rates.Aggregation and deposition of microplastics and nanoplasticsNanoplastics can be satisfactorily described through DLVO theoryDLVO theory in terms of Van der Waals and electrical double layer forcesElectrical double layer forces. Particle aggregation and deposition are governed by particle-particle and particle-surface interactions respectively. Smoluchowski model for aggregation is a very useful tool for modeling the microplastics kinetics in marine environment.The transport of microplastics is governed by Brownian diffusion while the contribution from gravitational sedimentation becomes important under favorable conditions for aggregation, where the rate of sedimentation of aggregates must be taken into account.Some microplastics contain chemical additives or have the ability to sorb contaminants already present in the aquatic environment. The accumulation of microplastics in the marine environment can facilitate the transport of these contaminants on local or global scale.

This chapter presents the different aspects involved in the study of pollutant sorption on microplastics (MPs). Introductory descriptions of the sorption processes are presented. The study of sorption capacity at equilibrium and kinetics is important to better understand the process. Early studies recognized the presence of chemicals on the MPs, and there are several of them performed throughout the world. These studies demonstrated that the presence of many chemicals found on MPs is due to sorption while in contact with polluted seawater. Later studies performed laboratory experiments and field studies to better understand sorption processes. In the case of polyethylene (PE), which is the major polymer of MPs found at sea, hydrophobic linear sorption is the main mechanism. However, polar compounds seem to sorb more on PE once it has polar functional groups on its surface that can be formed due to degradation or the development of biofilm. There are many studies that focus on these different aspects of sorption, but there are still several challenges related to studying sorption on MPs. These challenges are related to the existing analytical techniques that limit the size of MPs to be observed and handled during experiments. These create difficulties in order to perform highly relevant studies.

Microplastic debris in the environment degrades mechanically, chemically, and biologically. Degradation rates depend on polymer characteristics, such as structure, additives, and chemical composition, as well as environmental characteristics, such as temperature and humidity, depositional matrix (e.g., water, soil, sand, terrestrial versus aquatic), and depositional environment. The latter factor plays an integral role in determining whether microplastic particles are exposed to sunlight or buried beneath the water column or in the benthos, and in the amount of mechanical abrasion that occurs in settings such as beaches versus landfills. Although mechanical, chemical, and biological degradation can each break down microplastics into nanoplastics or oligomers and monomers, the combination of two or all three weathering processes normally interact to lead to microplastics degradation. In this chapter, the three types of degradation are summarized and examples are provided in which microplastics have been broken down in the environment and under simulated environmental conditions.

Microplastics (MPs) have become one of the most pervasive emerging pollutants in the environment because of their wide occurrence and high sorption ability for contaminants. Sorption and desorption by microplastics may play important roles in the fate of contaminants in aquatic ecosystems. The releasing of these contaminants from plastics into the environment and food chain may pose a greater risk to ecosystem health than the sorption and desorption processes of these contaminants from microplastics after ingestion. To better understand the environmental and ecological impacts of microplastics, there is an urgent need to study the adsorption and desorption behaviors of contaminants and microplastics in the environment. The absorption study of contaminants with microplastics is increasingly being studied. However, there is less knowledge about the release and the impact on the environment of compounds originating from the microplastics themselves. The previously released studies on inorganic and organic contaminants with MPs were reviewed. The contaminants include heavy metals, flame retardant, pesticides, antibiotics, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxin, etc. For heavy metals, it can be released from MPs under higher ionic strength biological fluids such as gut saline, especially for aged MPs. It indicates that the presence of MPs enhanced the bioavailability and toxicity of heavy metals on marine animals. More comprehensive risk assessment is required to study. For other organic contaminants, as the hydrophobic partitioning leads to adsorption between pesticides and MPs. Organic contaminants can therefore be released from MPs through leaching and emission because of lack of chemically bound to the MPs matrix. The research on the interaction between MPs and organic contaminants has been just started. More comprehensive risk assessment is required to study. More attention should be paid to the release and bioavailability study of organic contaminants with MPs. And as closer to our living environment, the combined pollution of soil MPs with contaminants should be paid more attention.

Microplastics (MPs) feature a range of characteristics such as size, shape, polymer type and associated density, and additive composition, which shape their sinking behavior. In addition, a number of processes affect MPs when they enter aquatic environments, causing physicochemical changes of the surface and microbial colonization. Together with the environmental conditions present in receiving water bodies, these traits modify sinking velocities, resulting in complex vertical MP dynamics in different habitats and at regional and global scales. This review gives a summary of recent literature describing MP surface degradation and the subsequent succession from early to mature biofilms. Biofilm formation is often followed by settling of multicellular eukaryotes on large enough MPs, further increasing density and sinking, but reversing processes such as defouling and ascent need to also be considered. Several modeling approaches have come a long way in explaining these complex processes, providing useful insight into MP sinking behaviors at different spatial and temporal scales, but they remain imperfect, as the diversity in environmental determining factors is high and changes over time and with environmental conditions. Biological interactions with MPs, especially uptake into and transfer within aquatic food webs override sinking patterns of individual MP particles. The review suggests that neither the ocean surface nor seafloor sediments reveal total MP input into aquatic environments, with implications for monitoring and risk assessments.

The presence of microplastics (MPs) in the environment has gained increasing attention in recent years. They are emerging environmental contaminants distributed worldwide that may have a negative impact on ecosystems, organisms, and even in human health. However, MPs are not alone in the environment and coexist with many other organic and inorganic contaminants, such as pharmaceuticals. Due to their physical-chemical properties, MPs have the ability to sorb pharmaceuticals from the surrounding water column in their surface, acting as vectors or carriers in the aquatic environment. MPs properties, such as type of polymer, particle size, surface area, polarity, and pharmaceuticals characteristics (e.g., log Kow, pKa), can directly affect their sorption behavior. Moreover, MPs may undergo different aging/weathering processes in the environment, which contribute to their degradation by decreasing MPs size and changing the particle surface topography and chemistry. These processes will induce changes in the physical-chemical properties of MPs, affecting their sorption behavior. In general, it is expected that aged MPs have a higher sorption capacity for pharmaceuticals than pristine ones. This chapter focuses on the existing studies on the sorption of pharmaceuticals on MPs. A review of the current knowledge on the sorption/desorption mechanisms involved in the sorption behavior of pharmaceuticals on MPs and how this is influenced by environmental factors (e.g., aging/weathering processes, pH, salinity, dissolved organic matter) is provided.

Microplastics from cosmetics, also known as “microbeads,” have been classified as a contaminant of emerging concern and are a global threat to aquatic ecosystems. After usage, these microplastics are flushed into the wastewater system, likely evade filtration, and are ultimately released to the aquatic environment in treated effluent discharge. Wastewater is likely a major pathway for microplastics to enter the aquatic environment, be transported over long distances, persist in the environment, bioaccumulate in food webs, and endanger human health. This chapter provides an overview of microplastics extracted from cosmetics, their pathways to wastewater and the aquatic environment along with their pollutant sorption properties. Sorptive properties of microplastics extracted from cosmetics primarily involve physisorption between microplastic surfaces and hydrophobic organic pollutants. To date, most microplastic sorption studies have involved microplastic debris commonly present in the aquatic environment. These studies have demonstrated that microplastics act as a vector for multiple pollutants. However, limited studies have provided a quantitative understanding of organic and inorganic pollutant sorption of cosmetic microplastics. These limited quantitative studies found that microplastic surface area, hydrophobicity, buoyancy, and aggregation influenced pollutant sorption in the aquatic environment. Furthermore, microplastic-sorbed pollutants were ingested by organisms at each trophic level. Additionally, digestive fluids were responsible for promoting microplastic-sorbed pollutants leaching into tissue, leading to bioaccumulation. Limited understanding of microplastic-sorbed pollutants from cosmetics calls for more studies to bridge the knowledge gaps and inform risk assessment and policy development.

In recent decades, plastic pollution has been the focus of environmental research, with particular focus on the distribution and potential effects of a novel emerging contaminant: microplastics. These solid particles of microscopic dimensions which have been found throughout the environment, from mountain tops to the bottom of the ocean, are a reason for concern. Studies so far have mainly assessed baseline concentrations in several environmental compartments (e.g., soil, air, surface waters, water column and biota), and as the research field developed, focus has shifted to the interactions between plastics, wildlife, the environment, and human health. Interactions with wildlife either by entanglement, uptake, or ingestion are commonly reported, nonetheless the ecotoxicological effects of microplastic ingestion are not fully understood. The complex relationships and interactions between persistent, bioaccumulative, and toxic chemicals (PBTC) and plastic litter items need to be further assessed. Future research challenges lie on understanding fragmentation and sorption rates of PBTC such as trace metals and persistent organic pollutants (POP) into and/or onto micro- and nanoplastics, but also understanding the effects caused by the leaching of additives into the environment. This chapter highlights the need to conduct ecotoxicological risk assessments that focus on the sorption mechanisms of pollutants into and/or onto plastics, in order to understand potential bioaccumulation mechanisms and the antagonist, synergistic or other relationships of PBTC, plastics, and the environment.

Microplastics (MPs) released into the oceans rapidly become colonized by a wide range of microorganisms and other biota. Phototrophic cells such as cyanobacteria and diatoms are the first to attach, but these are normally overtaken by proteobacteria, prior to the attachment of eukaryotes such as fungi and metazoa. The plastisphere (the ecosystem on the immersed plastic surface) is unique and may be specific to the type of plastic, depending on environmental conditions. Once colonized, the plastic surface is changed and the particles may sink to the benthos, or be carried on ocean currents to other waters, acting as rafts for invasive biota. MPs may be ingested by marine organisms. Cells in the surface biofilm are protected against external factors, partially by their exopolymeric layer (EPS), and transmission between other aquatic compartments may have disastrous effects on the ecosystems. Potentially pathogenic organisms have been detected in the plastisphere by DNA analysis; this has implications for control of human, fish, and coral diseases, but definitive proof is lacking. Bacteria capable of degrading plastics have also been detected; one of these (a PET-degrading species) produces two enzymes controlling this activity. However, no organism capable of rapid and complete degradation has yet been identified. There is limited information on the impact of MPs on invertebrate marine species. More work is necessary to determine the relationships between substrate-associated assemblages on MPs and the impacts on pelagic ecosystems.

Microplastics (MPs) have become an environmental threat due to their persistence, ubiquity, and potential harm to wildlife. Once dispersed in the ecosystem, MPs can sorb environmental pollutants such as organic compounds, metals, and emerging contaminants. This pollution has caused concern in the scientific community. A lot of research is focusing on MPs’ role as vectors for toxic chemicals in the biota. The aim of this chapter is to provide a review of studies of toxic pollutants adsorbed on MPs and present an overview of their ability to leach, bioaccumulating in the organisms. Moreover, the effects that the combination of MPs and adsorbed compounds have on the biota are explored. The importance of MPs as a vector for environmental pollutants is still mainly under discussion. The ecotoxicological consequences of the ingestion of contaminated MPs are still mostly understudied and require further research to be fully understood. Future research challenges include the risk assessment of long-term exposition to different combinations of MPs-contaminants, especially under environmentally relevant concentrations, and the determination of the relative importance of MPs-mediated input of pollutants in biota, taking into account the other exposure pathways.

Microplastics (MPs, <5 mm in size) are considered to be one of today’s major environmental problems. They are a ubiquitous persistent pollutant group that has reached into all parts of the environment – from the highest mountain tops to the lowest depths of the ocean. In their production, plastics have added to them a number of chemical additives in the form of plasticizers, colorants, fillers, and stabilizers, some of which with known toxicological effects to biota. When released into nature, MPs are also likely to encounter and sorb to their surfaces a variety of established pollutants including hydrophobic organic contaminants, trace metals, and pharmaceuticals. Importantly, MPs have been shown to be readily ingested by a wide range of organisms and it is this combination of biotic ingestion and chemical association that gives credence to the notion that MPs may impact the bioavailability and toxicity of both endogenousEndogenous pollutants and exogenous pollutants. This chapter provides an overview of the literature that has examined the role of MPs as chemical carriers to biota, with particular focus on aquatic organisms. The influence and interactions of MPs with endogenous and exogenous chemicals are reviewed before a more critical view of the relative importance of MPs as pathway for chemical transfer is provided. Lastly, the current state of the literature is placed into context of the needs of risk assessment highlighting the challenges to assessing the risk of MPs as chemical vehicles.

In the search for establishing well-founded analytical procedures for identification of microplastics (MPs), this chapter focuses on the effect on analytics of the interaction of MPs present in environmental or biological compartments with their media and the fact that MPs are not just pure polymers, as often assumed. The experience acquired along these recent years of intense research in the field suggests that most of the problems can either be adequately tackled (e.g., presence of biofilms) or constitute minor problems (e.g., presence of additives).

Microplastic pollution has been reported in marine, freshwater, and terrestrial ecosystems, from the sea surface to sediments, from beaches to the deep sea, from lakes to rivers, from the tropics to the poles, and in a wide range of organisms representing different trophic levels. Our current understanding of microplastic behavior has increased in recent years, but we still lack the ability to reliably predict exposure hotspots or exposure scenarios. This is further complicated by degradation processes, biofouling, and ingestion by organisms that change plastic particle properties and result in largely unpredictable changes to their environmental fate. While the quantity of data available on microplastic concentrations in different environmental compartments and different species has increased significantly, this is not matched with a comparable amount of experimental microplastic uptake, accumulation, and effects data, especially for organisms in freshwater and terrestrial environmental compartments. This chapter provides an overview of the current state of knowledge concerning the sources, fate, uptake, accumulation, and effects of microplastic in different environmental compartments. The roles of degradation, biofouling, and additive chemical content, as well as more uptake and mechanistic effects studies utilizing relevant microplastic reference materials, are highlighted as challenges that need to be addressed moving toward risk assessment of microplastic pollution.

The extensive utilization and mismanagement of plastic have led to the ubiquitous presence of microplastics in the environment. The freshwater system has received much attention recently due to the prevalence of high concentrations of microplastics concerning marine systems. Rivers, streams, lakes, and estuaries situated proximate to urban and industrial areas are undoubtedly prone to high amounts of microplastic contamination via wastewater effluents, agricultural runoffs, floods, and storm water. In some cases, even remote freshwater sources do not escape from microplastic pollution due to the input pathways flown across urban stretches. The distribution and fate of microplastics in the freshwater are affected by the physicochemical properties of the plastic particle, such as the size, shape, density, color, polymer type, and the natural processes such as biofouling, heteroaggregation, and weathering. Microplastics eventually enter into the marine waters, enabling their settlement in deep oceanic sediments or consumption by marine biota. Besides, particle dispersion and their transport pathways are governed by hydrological, geographical, and meteorological factors of the freshwater system. These factors are effectively utilized and assessed through models to predict their fate and distribution in the aquatic system, that is, Lagrangian transport model, Global NEWS model, Nano DUFLOW model, and INCA contaminants model. In freshwater, microplastics are eventually taken up by a wide variety of freshwater biota, initiated from primary producers at the base of the food chain up to higher trophic predatory animals. The interaction could lead to trophic transfer and bioaccumulation of microplastics over the food chain, posing hazardous toxicological effects on all trophic levels.

The increasing rate of worldwide plastic consumption and its release to the environment associated with a low degradation rate is resulting, nowadays, in its accumulation in all the ocean matrices, from sediment to water, in pelagic and benthic biota, from coastal to open ocean areas at each latitude.A big amount of manufactured plastic materials ends up in the oceans, floats on the sea surface, drifts in the water column, or sinks to the seafloor from the shorelines to the deep-sea. Consequently, microplastics are widely distributed in all the oceans, from the water surface to the sediments in the deep-sea, from the beaches to offshore. This is one of the critical global challenges, due to the fact that, having no borders, this pollutant affects the entire world ocean, from polar areas to the equator.Nowadays, the big deal is to understand the hotspot accumulation of microplastics, their sources and distribution mechanisms, to provide real actions to prevent an environmental worsening and to reduce the possible microplastic entry paths into the oceans.The purpose of this chapter is to give an exhaustive overview on the distribution and occurrence of microplastics in the worldwide oceans, considering the different matrices present in the sea environment, from the beach to the water surface and column, to the marine sediments, taking into account the peculiar characteristics of the matrices from the shoreline to offshore, from sublittoral to the hadal environments.

We all use plastics for a variety of purposes, and the amount of plastic produced and used is increasing worldwide, now reaching over 380 million metric tons (MMT) annually. Waste management in highly populated areas is currently insufficient to prevent large amounts of municipal waste from entering the environment; currently, the estimated annual mass of mismanaged waste is 80 MMT. With time, much of the plastic litter will degrade into microplastics, and once distributed, it is essentially impossible to remove. An estimated 4.8–12.7 MMT of plastics reach the ocean every year, while terrestrial systems are expected to accumulate 4–23 times more than the ocean. Waste generation, including microplastics, invariably follows human activities and plastic use. High-population densities infer higher generation and release of microplastics, leading to higher concentrations in urban areas. This chapter deals with the generation and release of microplastics, the dominant transport routes from major sources, and their distribution and fate in the urban environment. Proposed mitigation measures are also discussed. Methods of sampling, analysis, and reporting vary across countries, regions, and environmental compartments, causing uncertainties in mass-balances for microplastics. A few recent studies in or near urban areas provide new insight into patterns and trends of microplastics that underline areas of concern in terms of production, release, fate, and potential monitoring of microplastics in urban terrestrial and aquatic systems. A better understanding of major sources, distribution, and fate of microplastics is essential to engage in effective and sustainable preventive or mitigative actions targeting sites of high levels of microplastics.

For the past 150 years, the production of plastics has provided many solutions. However, the release of microplastics into soil systems presents hazardous potential, due to its resilience, endurance, and various interactions that occur in these complex matrices. Microplastics may cause effects on soil systems due to alteration of important soil properties to plants and organisms, such as pH, electrical conductivity, porosity, and density and by interacting with other contaminants such as metals or organic compounds in soil. Microplastics can also be transformed due to surrounding conditions, being transported, and accumulate in plants and organisms, causing a direct impact on individual species, as well as trophic chains composition and the soil ecosystem.The current chapter will present a critical review of the existing literature, focusing on the effects of microplastic environmental release to soil systems and its components: microbiota, micro-, meso-, and macrofauna and flora. The objective will be to provide a picture of the main ecological issues identified, knowledge gaps, and future directions for the assessment of microplastics effects on terrestrial environment.

Microplastics have been found in most parts of the world including the cryosphere, the part of the Earth’s surface characterized by frozen water. Surprisingly, high concentration of microplastics has been observed in some cryosphere areas. Shrinking of the cryosphere could release considerable amount of microplastics entrapped in sea ice and glaciers, posing serious threat to the already vulnerable ecosystems in these extreme habitats. Microplastics, and their associated contaminants, can be assimilated by biota in number of ways, such as filter feeding, suspension feeding, inhalation at air-water surface, consumption of prey exposed to microplastics, or via direct ingestion. Microplastics may bioaccumulate within individual organisms over time and be transferred up the food chain. Ingestion or even exposure to microplastics may pose a threat to the ecosystem. Leaching of chemical additives and contaminants from microplastics may alter community compositions of microbiota (e.g., bacteria, microalgae, and protozoa), and affect lower (e.g., invertebrates) and higher tropic level organisms such as fish, birds, and seals with unknown consequences for top predators, such as polar bears, and killer whales. In the first part of this review, the abundance and distribution of microplastics in the realm of the cryosphere is discussed. In the latter part, a comprehensive examination of scientific data regarding consumption of microplastics and the potential impact on organisms of the cryosphere, in particular marine organisms in the polar regions, is presented.

Because plastics are a multifunctional, resistant, easy-to-process, and affordable material, they play a central role in our daily life. However, their extensive use has become tainted by the continuous rise of plastic pollution worldwide, which generates, after slow photo, chemical, physical, and biological degradation, massive amounts of small-sized microplastics. Their ubiquitous nature in the environment but also in foodstuff and consumer packaged goods has revealed a potential threat to human health. In this chapter, a focus is given on the human gastrointestinal tract, as portal of entry but also first barrier and target for microplastics. We summarize the current state of knowledge on human oral exposure to microplastics and the characteristics of ingested forms (origin, occurrence, size, shape, polymer type, surface properties). Then, we highlight the physicochemical transformations of microplastics during digestion. Afterwards, we detail their potential impact on gut homeostasis disruption, including gut microbiota, mucus and epithelial barriers, considering in vitro and in vivo studies (rodents). Finally, this chapter points out future research directions about microplastics in the field of human intestinal health. Special emphasis is given to the critical need of developing robust in vitro gut models to adequately simulate human digestive physiology for better gut health risk assessment and management of microplastics.

Over the past decade, numerous observations have indicated the uptake of microplastics by species destined for human consumption. This has resulted in widespread concern regarding the impacts of microplastic pollution on commercially important species and given rise to questions regarding the implications for food safety. Despite these concerns, the level of information outlining the uptake and impact of microplastics in aquatic species is largely incomplete. The lack of breadth and depth in the available data prevents us from satisfactorily answering many of the core questions that are presented by this relatively novel pollutant. Nevertheless, what information is available presents a picture of a contaminant which affects the whole food chain, including species which are internationally important in terms of livelihoods and dietary protein. To date, there has been limited evidence for widespread impacts as a result of microplastic ingestion; however, as the concentrations of microplastics in aquatic environments continue to rise, so too do the risks of individual, population, and ecosystem level effects, which may affect both industry productivity and food security.

While the physical impact of meso- and macrodebris on biota is broadly documented, microplastics (MPs) are also known to induce various detrimental effects on organisms but their physical impacts are still under debate. Scientific reports indicate that our knowledge of the physical impact of MPs on biota is very limited. The most frequent effects observed have been obtained from laboratory experiments and shown perturbations of behavior and growth, revealing that the most adverse impacts are not mechanical. Data from field observations generally concern the occurrence of debris but not specifically plastics, while size categories of debris are often omitted or do not follow a standard categorization. While laboratory experiments enable the evaluation of various negative acute/chronic effects through dose/response relationships, they may not adequately reflect natural conditions. However, these tools may provide original and comparable data on the various impacts in relation to the sizes, types, and shapes of MPs.Given current knowledge, technical gaps, and the constraints involved in monitoring the mechanical effects of MPs, no standard methods for assessing the physical impact of MPs on biota have been proposed until now for regular and long-term monitoring. This remains a challenge before policy-makers can fully appreciate the factors involved.

Microplastics (MPs) have become a global concern, owing to frequent detection in aqueous and soil eco-systems. Their transport, release, and the influence of MPs-bound chemical contaminants on aquatic life and soil organisms have been widely investigated. Research studies have confirmed interaction of both organic and inorganic contaminants towards MPs. Weak bond formation of contaminants such as toxic metals and antibiotics with MPs, leading to rapid desorption whereas strongly bound contaminants are taken along with the microplastic particles as a carrier both in aquatic and terrestrial environments. However, polymer type, color, particle size, and weathering degree are factors affecting both adsorption and desorption capacities of contaminants. MP’s behavior as a vector has influenced the transport of molecules such as pharmaceuticals, i.e., antibiotics from one place to another, which may develop antibiotic resistance in microbes. Moreover, toxicological effects have been identified on aquatic vertebrates and invertebrates, resulting in digestive tract obstructions and inflammation; however, they cannot be delineated from MPs or due to the adsorbed contaminants. Biosolid application to farmlands may transport MPs-bound contaminants to the soil system, reducing the plant performance. At the same time, these contaminants can be taken up and accumulate in crops. Constant exposure to chemical contaminants from MPs leads to bioaccumulation of toxic compounds in plants and animals.

Since half a century, aquatic environments are polluted by plastic debris resulting in its global distribution even to remote systems. Immediately after entering the aquatic environment, microorganisms colonize on plastic surfaces and build up a biofilm, the so-called plastisphere. These epiplastic biofilms have been identified to play a key role in the fate and effects of environmental plastic but knowledge on epiplastic communities is scattered and often derives from laboratory experiments. Aim of this chapter is to shed light on the “triple role of biofilms” in fate and effects of environmental plastic to improve environmentally realistic research and risk assessment: (i) Biofilms can be shaped by the material properties in structure and functions. (ii) In turn biofilms influence the weathering, fate, and potential effects of plastic in the environment. (iii) Finally, plastic represents a new habitat for colonizing microorganisms, which might have system-wide interferences. Therefore, recent literature is reviewed illustrating the mechanisms of the first attachment of microorganisms on surfaces and their implications for weathering and fate of plastic in the environment. Current knowledge on the role of biofilms for partitioning of chemicals in the three-media system of plastic, biofilm, and the water phase is provided. Finally, insights into the potential ecologial role of epiplastic microbial communities for the aquatic environment are given. As plastic pollution has been identified even in remote systems, cross-system investigations considering the role of epiplastic biofilms for aquatic systems differing in vulnerability need to be performed to better inform environmental risk assessment of plastic pollution.

Microplastics pollution of terrestrial and marine environmental compartments is an issue of concern worldwide, but information on the key sources, pathways, distribution, and impacts is still scarce in many cases, fragmentary at best, and typically difficult to compare owing to a lack of harmonization in methodologies. In this chapter, we present the latest evidence of microplastics as a global threat, together with current knowledge gaps, the challenges associated with establishing a global monitoring system and what legislative framework might be needed for their control. The chapter will also describe the complexity of this environmental problem, highlighting the key reasons for why regulation at the local, regional, and global levels is currently limited and discussing possible ways forward.

Due to the fact that microplastics are a global environmental problem, clarity about microplastic pollution, its entry path and distribution, its behavior in ecosystem, and its influence on human life is important to setting political restrictions and promoting efficient reduction strategies.During the last two decades, the scientific community started their intensive work in different fields of microplastic research. In this book chapter, we focus on the overview of the current state of knowledge about microplastic pollution in the environment and entry paths. Additionally, we present fields of application in which the removal of microplastics from water is necessary or useful. We divide our results into two parts. Part A summarizes the state of political measures and regulations. In Part B, we present end-of-pipe technological solutions analyzing the state of the art concerning an overall particle elimination. In addition to the state of the art, we focus on new innovative strategies. Here, microorganismic effect and agglomeration-fixation reaction are most promising, because they do not need high investment costs or complicated technological systems.

Marine microplastic pollution is increasingly seen as a transboundary problem that requires priority attention and represents a unique governance challenge, given the associated risks and ubiquity of microplastics in the marine environment. Various governance measures to reduce the use of microplastics and to prevent further pollution of the marine environment have been adopted or are under consideration by actors at different levels of governance. This chapter reviews these governance measures and we argue that the primary concern of regulators should be to prevent both primary and secondary microplastic leakage into the marine ecosystems. We proceed with the further assumption that most microplastic enters marine ecosystems from land-based sources, so policies designed to curtail this particular form of plastic pollution are given due emphasis in this chapter. The prevention of microplastic pollution in the oceans is inherently complex, and this chapter examines the governance framework on the global, regional, national, and subnational levels. Both international collaboration and complimentary governance by non-state actors are important in order to effectively prevent microplastic pollution entering the oceans. Evidence from the examples analyzed throughout the chapter confirms that a comprehensive, systems-level approach, including a combination of diverse prevention measures and the involvement of a wide range of actors, is necessary.

This chapter presents a summary of the main characteristics of sewage treatment plants as sink and source of microplastics to the environment, the sampling procedure and isolation and analytical techniques, as well as removal rates and the best available technologies for their removal. Despite being a barrier, wastewater treatment plants have proved to be an important source of microplastics into the environment, both from treated effluent and the application of sludges in agricultural soils. We discuss about sampling collection methodologies, further pretreatment processes and density separation of microplastics by means of different salt solutions. Visual identification coupled to a spectroscopic technique seems to be essential in order not to under- or overestimate the microplastic content. Concentration of microplastics in sewage plants has been reported with large variations among researchers as well as the polymer types identified, being polyethylene, polypropylene, and polystyrene the most observed ones. It seems the removal rate of microplastics in sewage plants increases with decreasing size, may be because an insufficient hydraulic retention time for the removal of large microplastics, and the number of wastewater treatment stages may affect the final concentration in the effluent. The removal rate for secondary treatment ranges from 64% to 99%, and the implementation of a tertiary process, that is, disc filters, rapid sand filters, dissolved air flotation, or a membrane bioreactor, usually reduces the concentration of microplastics in the final effluent. However, some studies have highlighted the importance of first stages in the sewage treatment plant, as skimming and primary clarifiers, not always reaching a lower microplastic concentration after a tertiary treatment.

The problematic of microplastics pollution in the terrestrial environment has only received attention recently by different sectors of the world society. Although most part of the research has focused in the beaches and oceans, the agricultural sites are the most vulnerable areas, because substrates containing microplastics, such as sewage sludge and compost, produce an ecosystem alteration by itself and also they constitute a vehicle of these particles that are unintentionally added to the agricultural soils into deeper soil layers, and in most of the cases, end up later on in the marine environment through run-off or by means of submarine groundwater discharges. In addition, the use of plastic mulch, which was initially a very innovative invention to maintain soil moisture and promote crops, is now a source of contamination when it is not properly collected from the ground. In this chapter, a discussion about the steps to follow to perform a remediation of soils contaminated by microplastics will be discussed. This chapter does not intend to present new alternatives or solutions, but rather discusses what could be the actions to follow in order to develop a technology that could be useful, accessible, and applicable in all corners of our planet. Nevertheless, until now there is no magic wand to make the plastic pollution disappear in the soil of agricultural sites. However, microorganisms belonging to digestive tract of invertebrates (i.e., those from the phylum Firmicutes) constitute a very promising tool in order to solve the problem of plastic pollution in soils.

Polymeric materials have had an exponential growth since the Second World War, so that in 2018 the annual world production was 359 million tons. This has generated a contamination problem because of its prolonged exposure to various chemical and environmental factors which have caused the formation of particles with a size less than 5 mm with a vast surface area and chemically stable and adjustable surface. For these reasons, these particles called microplastics (MPs) have been used as vectors for chemicals in the environment and, recently, in the removal of several pollutants from water.In this chapter, some representative examples of the use of microplastics for sorption of contaminants from water (pharmaceuticals, metal ions, and other organic compounds) are shown. The chapter is organized into two parts: the first part addresses MPs of commercial origin (virgin) and those reused after being collected from field, while the second part addresses representative examples of MPs synthesized and/or functionalized with the purpose of uptaking specific contaminants.

Plastic pollution is a result of unsustainable use and disposal of plastics in modern society and a reflection of the fragilities of our political and economic systems. This fact became even more evident under a recent viral pandemic that shivered the pillars of sustainability. During the state of emergency, several plastic reduction policies at regional and national levels were postponed, and plastic waste managementWaste management was reprogramed with landfillLandfills and incinerationIncineration being prioritized. These political actions, along with a sudden compulsive and unsustainable public behavior, have been resulting in an increment on single-use-plasticSingle-use-plastics littered worldwide with potential for short- and long-term negative impacts on both environmental and human healthHuman health.Current preventive strategies are unable to compete with increasing quantities of plastic entering the environment, and clean-up measures revealed to be relatively expensive, labor-intensive, and inefficient in eliminating microplastic debris from the environment. The use of microorganisms capable of biodegrading plastics has emerged as a promising low-cost, low-technology, and eco-friendly approach for eco-remediation of field contaminated sites with plastic debris. This chapter presents a comprehensive review of the role of microorganisms on plastics biodegradation, detailing the major contributors, potential degradation pathways, and biotic and abiotic drivers. It also explores potential biotechnological tools, including microbial consortia, genetic engineering techniques, that might become a crucial part of the eco-remediation of plastic polluted sites. Finally, it discusses the importance of such approaches in the eco-remediation of micro-nano plastics and addresses future practices for the bioremediation of plastic-polluted sites in a sustainable way.

Despite the unquestionable benefits of plastics to human activitiesHuman activities, their intense use has generated huge quantities of waste worldwide. The inappropriate handling of plastic residues is currently one of the main environmental and societal issues. Studies assessing the presence of micro- and nanoplastics in marine, freshwater, and terrestrial ecosystems, as well as their effects on biota, increase every day.However, research on micro- and nanoplastic pollution of groundwater is lagging behind. Groundwater ecosystems and associatedBiodiversitygroundwater ecosystems and associated biodiversity provide many ecosystem servicesEcosystem services having essential roles in the planet, and for human life and development being responsible for replenishment of rivers and lakes and a source of drinking and irrigationIrrigation water to populations. Despite their paramount importance, only a few studies have evaluated the presence of microplastics in aquifersMicroplasticsin aquifers. Due to their widespread occurrence and persistence, microplastics were already found in aquifers with an abundance of approximately 16 particles/L.After a brief introduction to the economic and ecological importance of groundwater and aquifers, insights regarding the potential sources of micro- and nanoplastics to aquifers, and the research needed to adequately protect groundwater ecosystems fromPlastic pollutiongroundwater ecosystems plastic pollution are provided. In particular, we focus on the need for effective and standardized monitoring of plastic particlesMonitoring, of plastic particles in groundwater, the need for research on the fate and transport of microplastics in soilsMicroplasticsin soils and hyporheic zonesHyporheic zones to groundwaters, and on the necessary evaluation of ecological effects of plastic particles on groundwaterBiodiversitygroundwater biodiversity. In conclusion, transdisciplinary studies addressing groundwater contamination by micro- and nanoplastics are required to ensure the sustainabilityGroundwatersustainability and conservation of groundwaterGroundwaterconservation of ecosystems.

Surveillance of seafood for microplastic is in high demand, but there are challenges in the establishment of appropriate methods. Even though there are more than hundred scientific publications presenting numbers about the occurrence of plastics in seafood organisms, currently, these numbers are largely not comparable and afflicted with high uncertainty. They represent rather pioneering work, than surveillance. The research field is developing rapidly, continuously challenging and updating definitions and descriptions on the location, quality and quantity of microplastic. A major reason behind those challenges is of a new type, due to the particular nature of this pollutant, as opposed to other previously analyzed pollutants, which are soluble. When dealing with particle uptake into organisms, we claim that it is pivotal to take into account the size and shape of the particles. Most often, only plastic particles above several hundred μm and only from the gastrointestinal tract were included in field studies, typically leading to observations of on average 0–3 particles per fish. However, for both seafood organisms and human health, plastic particles in edible tissue are of higher concern, than those passing through the gastrointestinal system. According to exposure studies, the size of microlitter particles that are most likely to be transported into tissue and have accumulation potential, is lower than 50 μm. The few publications investigating the smaller size classes and tissues, do detect and report microlitter contamination, and therefore, warrant further investigation. Additionally, appropriate quality control needs to be included, and measurement uncertainties assessed.

The United Nations Sustainable Development Goal (SDG) 14 is known as “life below water” and focuses on the ocean. Among other aspects, it regards all forms of pollution, including marine debris. Here we discuss how one specific type of marine debris is a horizontal issue among this and other SDGs. Microplastics are categorized generally as plastic items smaller than 5 mm in maximum length. They have been found globally in our ocean, affecting biota and environmental quality in various ways. These tiny particles have also more recently been associated with threats to human health. However, with unharmonized sampling and analytical methods, microplastics are still difficult to monitor and assess. Increasing recognition of the origins and impacts of microplastic pollution is essential for the development of strategies that can effectively address the problem. In this context, the United Nations SDG’s framework is a promising basis to holistically and scientifically discuss the transversality of microplastics. In this respect, the United Nations Decade of Ocean Science for Sustainable Development could be a lighthouse, building a knowledge-based pathway to achieve SDG 14 and contributing to address other global challenges.

At the Leibniz Institute for Baltic Sea Research, biological and ecological effects of microplastics (plastic particles <5 mm) have been explored by scientists for a decade. Here we add to this research a new microplastic-related topic by exploring their potential to be preserved in the geological record as technofossils. Microplastics are resistant to most forms of degradation and are incredibly mobile. These features highlight microplastics as potential markers of the Anthropocene epoch, a new time unit that might become part of the geological time scale. Using general biostratigraphic practices, we illustrated the role of microplastics and their constituent polymers in defining the beginning of the Anthropocene. This analysis is discussed together with the available literature on the topic to conclude that microplastics have a great potential as auxiliary or secondary markers of the Anthropocene, opening a range of avenues to be further explored in future research.