A Bayesian analysis of the factors determining microplastics ingestion in fishes

Geographical and ecological factors affect microplastic body burden in marine fish at global scale

Microplastic (MP) contamination has been identified as a worrisome environmental issue at the global level. Fish are the taxonomic group more extensively investigated to assess MP contamination in marine environment. A large variability in MP bioaccumulation (i.e., body burden) was reported in fish but to date there is a dearth of information concerning the drivers underlying this process. The present systematic review aimed at summarizing the results of the scientific literature on MP body burden in the digestive tract of marine fish to quantitatively shed light on the contribution of different geographical (i.e., latitudinal origin of the sample, distance from the coastline and field- or marked-collected) and ecological (i.e., trophic strategy, milieu, and body size) factors driving bioaccumulation. The mean (±SE) MPs/individual was 4.13 ± 2.87, and the mean MPs/ww (i.e., MPs/g) was 5.92 ± 0.94. Overall, MP abundance expressed as MPs/individual of fish from tropical areas was significantly higher compared to the other latitudinal bands, with species sampled close to the coastline that accumulated a larger number of MPs compared to those collected offshore. Neither the trophic strategy, nor the milieu and the market or field origin of fish explained the MP body burden. However, fish body size resulted as a determinant of MP body burden (as MPs/individual), with small fish accumulating a lower amount of MPs compared to larger ones. Qualitatively, but not statistically significant, similar results were generally obtained for MPs/ww, except for an opposite, and significant, variation according to species body size. Our findings showed that geographical, rather than ecological factors represent the main drivers of MP body burden in marine fish, suggesting that environmental variables and/or local pollution sources mainly contribute to explaining the large variability underlying the ingestion and bioaccumulation processes of these contaminants.

Occurrence of microplastics and metals in European seabass produced in different aquaculture systems: Implications for human exposure, risk, and food safety

Microplastics (MPs) are emerging contaminants of increasing concern as they may cause adverse effects and carry other contaminants, which may potentially compromise human health. Despite occurring in aquatic ecosystems worldwide, the knowledge about MP presence in different aquaculture systems and their potential impact on seafood products is still limited. This study aimed to determine the levels of MPs in water, feed, and European seabass (Dicentrarchus labrax) from three relevant aquaculture systems and estimate human exposure to MPs and metals through seabass consumption. The recirculating aquaculture system (RAS) had the highest MP occurrence in water and feed. MP levels in seabass followed the aquaculture system's levels in water and feed, with RAS-farmed fish presenting the highest MP load, both in the fish gastrointestinal tract (GIT) and muscle, followed by pond-, and cage-farmed fish. MPs' characteristics across aquaculture systems and fish samples remained consistent, with the predominant recovered particles falling within the MP size range. The particles were visually characterized and chemically identified by micro-Fourier Transform Infrared Spectroscopy (μFTIR). Most of these particles were fibres composed of man-made cellulose and PET. MP levels in GIT were significantly higher than in muscle for pond- and RAS-farmed fish, MPs' bioconcentration factors >1 indicated bioconcentration in farmed seabass. Metal concentrations in fish muscle were below permissible limits, posing low intake risks for consumers according to the available health-based guidance values and estimated dietary scenarios.

Trophic transfer and biomagnification of microplastics through food webs in coastal waters: A new perspective from a mass balance model

Since the 1950s, plastic pollution and its risk have been recognized as irreversible and nonnegligible problems as global plastic production has increased. In recent years, the transport and trophic transfer of microplastics (MPs) in biotic and abiotic environment have attracted extensive attention from researchers. In this study, based on the Ecotracer module from Ecopath with Ecosim (EwE) model, the marine ranching area of Haizhou Bay, Jiangsu Province, China, was taken as a case study by linking the environmental plastic inflow with MPs in organisms to simulate the variation of MPs in the marine food web for 20 years, as well as its potential trophic transfer and biomagnification. We found that the concentration of MPs in top consumers first increased when the concentration of MPs in the environment increased, while that in primary consumers first decreased when the concentration of MPs in the environment decreased. Moreover, high TL consumers had a stronger ability to accumulate MPs, and pelagic prey fishes was the opposite. From the perspective of the food web, all functional groups showed significant trophic magnification along with the trophic level and no biodilution. Generally, there is a direct relationship between the MPs in marine organisms and environmental inflow. If the pollutants flowing into the environment can be reduced, the MP pollution problem in coastal waters will be effectively alleviated. Our research can further provide a scientific basis for ecological risk assessment and management of MPs and biodiversity protection in marine ecosystems.

Transfer pattern of microplastics at an individual level: A case study of two typical Sciaenidae fish in coastal waters

Microplastics (MPs) are recognized as global pollutants. The occurrence and distribution of MP transfer at the species level have been reported, but few studies have focused on the individual level. In this study, two typical migratory demersal species (Collichthys lucidus and Larimichthys polyactis, family Sciaenidae) from the coastal waters of the Lvsi fishing ground were selected to analyze the distribution characteristics of MPs in their gastrointestinal tracts and to explore the potential biomagnification of MPs in different body lengths. The results showed that the main MP color found in both species was blue (>80 %), while the main MP shape was fiber (>90 %), and the main MP polymer type was polyethylene terephthalate (PET) (>70 %). Overall, the abundance of MPs in C. lucidus (3.24 ± 1.57 pieces/fish) was higher than that in L. polyactis (2.24 ± 0.56 pieces/fish). The abundance of MPs in C. lucidus with a body length >90 mm was significantly higher than that with a body length <90 mm, and no significant difference was found in L. polyactis. We believe that the shift in feeding habits during the life history of the two species is an important factor that affects the variation in MPs between body lengths. Additionally, there was a significant positive correlation between MPs and the length (weight) of C. lucidus but no correlation in L. polyactis. There was no significant correlation between trophic level and MPs in either species. This indicated that MP bioaccumulation only occurred in C. lucidus, and MP biomagnification did not occur in either species. We suggest that further research be conducted on MPs ingested by more species at an individual level regarding the biomagnification/bioaccumulation phenomenon. This will help further elucidate the characteristics of MP transfer in the food webs of ecosystems and provide theoretical support for understanding MP pollution in coastal waters.

Suspected anthropogenic microparticle ingestion by Icelandic capelin

Documented ingestion of microplastics and other anthropogenic microparticles (AMP) by marine fishes has increased over the last decade. However, baseline datasets on AMP ingestion in Arctic fish species are limited. This study documents AMP ingestion in Icelandic capelin (Mallotus villosus) and investigates how this relates to several biological variables. A total of 160 capelin gastrointestinal tracts were sampled and digested using 10 % potassium hydroxide and visual inspection protocols. A total frequency of occurrence (%FO) of 52.5 % and a mean AMP abundance of 1.33 ± 2.37 per individual was found (particles > 45 μm). The colour of AMP detected was significantly different between sampling locations. However, no differences in %FO or mean AMP abundance were detected between sampling locations or related to body size, gut fullness, or sex. This research contributes to the growing body of knowledge on AMP ingestion by Arctic marine species.

Feeding behavior and species interactions increase the bioavailability of microplastics to benthic food webs

Plastics are pervasive in aquatic ecosystems, in which they circulate in the water column, accumulate in sediments, and are taken up, retained, and exchanged with their biotic environment via trophic and non-trophic activities. Identifying and comparing organismal interactions are a necessary step to improve monitoring and risk assessments of microplastics. We use a community module to test how abiotic and biotic interactions determine the fate of microplastics in a benthic food web. Using single-exposure trials on a trio of interacting freshwater animals (the quagga mussel Dreissena bugensis, a filter feeder; the gammarid amphipod Gammarus fasciatus, a deposit feeder; and the round goby Neogobius melanostomus, a benthivorous fish), we quantify the (1) uptake of microplastics from environmental routes (water, sediment) under six exposure concentrations, (2) the depuration capacities over 72 h, and (3) the transfer of microbeads via trophic (predator-prey) and behavioral interactions (commensalism, intraspecific facilitation). Under 24 h exposures, each animal of our module acquired beads from both environmental routes. The body burden of filter-feeders was higher when they were exposed to particles in suspension, whereas detritivores had similar uptake from either route. Mussels transferred microbeads to amphipods, and both invertebrates transferred beads to their mutual predator, the round goby. Round gobies generally displayed low contamination from all routes (suspension, sedimented, trophic transfer) with a higher microbead load from preying on contaminated mussels. Higher mussel abundance (10-15 mussel per aquaria, i.e., ~200-300 mussels·m2) did not increase individual mussel burdens during exposure, and neither did it increase the transfer of beads from mussels to gammarids via biodeposition. Our community module approach revealed that the feeding behavior of animals allows microplastic uptake from multiple environmental routes, whereas trophic and non-trophic species interactions increased their burden within their food web community.

Occurrence and accumulation of microplastics in commercial fish in the coastal waters of the Lvsi fishing ground in China

In recent years, there has been an exponential increase in the research popularity of microplastics (MPs) in offshore marine environments. However, there is still a gap in the research on the accumulation of MPs in different tissues of aquatic organisms and the trophic transfer of MPs between aquatic organisms. The common occurrence of MPs in the gills and guts of 11 species of commercial fishes was examined in the coastal waters of the Lvsi fishing ground (LSFG). The obtained results showed that >85 % of MPs existed in the gills and guts of these fish, and the abundance was 2.39 ± 1.38 pieces/fish and 2.56 ± 1.42 pieces/fish, respectively. Fibrous and blue are the most common colors and shapes of MPs, and PET is the main polymer type. At the species level, the abundance of MPs in the gills and guts of a few fishes (e.g., Larimichthys polyactis, Setipinna tenuifilis, Collichthys lucidus) decreased with increasing body length and body weight (P < 0.05). At the community level, this situation was not significant (P > 0.05). With increasing trophic level (TL), MPs tended to decrease in the gills (trophic magnification factor, TMF = 0.86) but did not significantly vary in the gut. We believe that MPs are multidimensional pollutants, and their accumulation in tissues/organs of organisms has not been accurately and qualitatively determined. To establish the relationship of MP transport and trophic transfer among water, sediments and organisms, we suggest that more efforts should be made to investigate MPs in aquatic organisms in the coastal waters of LSFG and to increase the examination of MPs in the water column and sediments. This study will help us improve our understanding of MPs pollution, and provide a good reference and basis for the management, monitoring and implementation of pollutants in marine organism of coastal water.

Effects of microplastics on the toxicity of co-existing pollutants to fish: A meta-analysis

Aquatic ecosystems are among the main destination for microplastics (MPs) in the environment. MPs that enter aquatic ecosystems can contribute to pollution together with other co-existing pollutants. However, whether such pollution results in higher or lower toxicity to fish than that caused by co-existing pollutants alone remains controversial. This study aimed at closing this research gap based on 1380 biological endpoints under the background of environmental MP concentrations collected from 55 laboratory studies. Overall, MPs in co-existing pollutant solutions significantly increased the toxicity to fish. Specifically, MPs elevated negative effects on the immune system, metabolism, and oxidative damage. Subgroup analysis indicated that changes in toxicity were related to fish life stage and MP size, but not to co-existing pollutant or MP type. Meta-regression analysis indicated that changes in toxicity were not related to the logarithm of the octanol-water partition coefficient (logKow) or exposure time. Finally, the differences between laboratory research and the actual aquatic environment were discussed from four aspects: MPs, co-existing pollutants, environmental factors, and experimental objects. Our study provides a basis for further understanding the potential impact of MPs on aquatic organisms from a combined pollution perspective. Moreover, our results can provide a reference for the conservation and management of aquatic ecosystems.

Study of feeding biology and diet-associated microplastic contamination in selected creek fishes of northeastern Arabian Sea: A multi-species approach

This study investigated the diet composition and microplastic contamination in six fish species collected from the creek area of northeastern Arabian Sea. The results show that the diet of the fish is mainly composed of shrimps, algae, fish, and zooplankton, with microplastics constituting up to 4.83 % (Index of Preponderance) of their diet. The average abundance of microplastics ranges from 5.82 to 7.69 items per fish, and their ingestion is influenced by seasonal variation, gut fullness, and trophic level. Microplastic contamination has no significant effect on the condition factor and hepatosomatic index of the fish species. However, polymer hazard index indicates that microplastic pollution in fish is associated with a low to high risk factor, which might cause potential harm to aquatic lives and higher vertebrates via food chain. Therefore, this study highlights the need for immediate attention and effective regulations to reduce microplastic pollution to protect marine life.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

From inshore to offshore: distribution of microplastics in three Italian seawaters

A comprehensive understanding of the concentration of microplastics (MPs) in seawaters is essential to implement monitoring programs and understand the impacts on ecosystems, as required by the European legislation to protect the marine environment. In this context, the purpose of this study is to investigate the composition, quantity, and spatial distribution of microplastics from coastal to offshore areas in three Italian seawaters. In addition, the distribution of microplastics between surface and subsurface water layers was analyzed in order to better understand the dynamics of MPs in the upper layers of the water column. A total number of 6069 MPs (mean total concentration of 0.029 microplastics · m^-2) were found to be heterogeneous in type, shape, and color. In general, MPs concentrations decrease with coastal distance, except when environmental forcings are predominant (such as sea currents). Moreover, the amount of surface MPs was almost four times that of subsurface microplastics, which consisted mostly of fibers. In light of these results, it becomes clear how critical it is to plan remediation actions and programs to minimize microplastic accumulations in the sea.

The different ways microplastics from the water column and sediment accumulate in fish in Haizhou Bay

Global microplastic (MP) pollution is a serious environmental problem that has been found in various ecosystems, especially marine ecosystems. In this study, the water (surface, middle and bottom water), sediment and fish (pelagic, demersal and benthic fish) in the artificial reef area and adjacent waters in Haizhou Bay were collected, and the mechanism of MP transmission among the three media was analyzed. The results showed that >96 % of the plastics in the region were MPs. The shape of MPs was mainly fibrous (water (73.3 %), sediment (56 %), fish (95.3 %)), color was mainly blue (water (49.3 %), sediment (47 %), fish (72.3 %)), and the material was mainly PET (water (39.6 %), sediment (33 %), fish (86.6 %)). We found that, except for the natural deposition of MPs, MPs could be ingested by pelagic fish and transmitted through vertical movement in the water, while there was an interaction between MPs in benthic fishes and the middle-bottom waters. In addition, as relevant variables, body length and body weight were more likely to explain the number of MPs ingested by fishes than were δ13C and δ15N. Therefore, based on the linear relationship between δ15N and body length, we concluded that there was a weak trophic magnification effect of MPs ingested by fish in this region. This study provides unique information for further exploring the factors influencing the spatial distribution of MPs and the transmission mechanism of MPs in fish.

Sources, sinks and transformations of plastics in our oceans: Review, management strategies and modelling

Currently, 60-80 % of litter is plastic, and almost 10 % ends up in the ocean directly or indirectly. Plastics often suffer from photooxidation producing microplastics and these microplastics derived from the breakdown of larger plastics are called secondary microplastics. These compounds simply cannot be extracted from the oceans, and once mixed, they enter the food chain and may have toxic effects. This work reviews the current existing information on the topic in the scientific literature. Then, the current plastic management strategies in the marine environment are analysed, with the objective of identifying possible needs and improvements from a sustainable point of view, and to define new approaches. Simultaneously, a material flows analysis in different media of the marine environment is carried out using system dynamics. A preliminary model of plastics mobilization into the ocean to other media of the marine environment (like sediments and biota) is developed and validated with the existing data from the previous steps of the work. This work expands the current knowledge on the plastics management, their transformations and accumulation in the marine environment and the harmful effects on it. Likewise, preliminary dynamic model of mobilization of plastics in the ocean is implemented, run, and validated. The developed model can be used to predict trends in the distribution of the plastics in the ocean with time. In addition, the most important reservoirs of plastics in the ocean can be observed. Although plastics undergo transformations in the marine environment, it is not a means of disposal since most of them are non-biodegradable. Most plastics accumulate on the seabed. The proportion of microplastics found in sediments is higher than that of macroplastics.

A versatile approach to evaluate the occurrence of microfibers in mussels Mytilus galloprovincialis

Microplastics of fibrous shape are esteemed to be the most abundant micro-debris form present in the environment. Despite the occurrence of microfibers in fish may pose a risk to human health, the literature is scarce regarding studies on the contamination in commercial marine fish mostly due to methodological issues. In this study, a versatile approach, able to discriminate among natural and synthetic microfibers according to the evaluation of specific morphological features, is proposed in farmed mussels (Mytilus galloprovincialis). The approach was useful to determine that microfibers were present in 74% of mussel samples, with a mean number of 14.57 microfibers/individual, corresponding to 3.13 microfibers/g w.w. A negative correlation between the size of analysed mussels and the amount of microfibers/g w.w. was detected, showing that smaller specimens contained more microfibers than the larger ones. This work paves the way to further studies aimed to adequately assess the risk that microfibers may pose to marine biota, also considering the commercial value as seafood items of many species of the Mytilus genus and the potential implication for human exposure.

One is not enough: Monitoring microplastic ingestion by fish needs a multispecies approach

The development of monitoring programs based on bioindicators is crucial for assessing the impact of microplastic ingestion on marine organisms. This study presents results from an Italian pilot action aimed at investigating the suitability of a monitoring strategy based on a multispecies approach. The benthic-feeder Mullus barbatus, the demersal species Merluccius merluccius, and the pelagic-feeder species of the genus Scomber were used to assess the environmental contamination by microplastics in three different marine areas, namely Ancona (Adriatic Sea), Anzio (Tyrrhenian Sea), and Oristano (Western Sardinia). Microplastic ingestion frequencies were higher in samples from Anzio (26.7 %) and Ancona (25.0 %) than Oristano (14.4 %), suggesting a relationship between microplastic bioavailability and the proximity to urban settlements and river flows. Furthermore, microplastic ingestion was affected by the feeding habits of the examined species. The detected differences reinforce the hypothesis that a multispecies approach is needed to evaluate microplastic ingestion by marine animals.

Large size (>100-μm) microplastics are not biomagnifying in coastal marine food webs of British Columbia, Canada

Microplastics (MPs) contamination in marine environments is of increasing concern, as plastic particles are globally ubiquitous across ecosystems. A large variety of aquatic taxa ingest MPs, but the extent to which animals accumulate and transfer MPs through food webs is largely unknown. In this study, we quantified MP uptake in bivalves, crabs, echinoderms, and fish feeding at different trophic levels at three sites on southern Vancouver Island. We paired stable-isotope food web analysis with MP concentrations in digestive tracts across all trophic levels and in fish livers. We then used Bayesian generalized linear mixed models to explore whether bioaccumulation and biomagnification were occurring. Our results showed that MPs (100-5000 μm along their longest dimension) are not biomagnifying in marine coastal food webs, with no correlation between the digestive tract or fish liver MP concentrations and trophic position of the various species. Ecological traits did, however, affect microplastic accumulation in digestive tracts, with suspension feeder and smaller-bodied planktivorous fish ingesting more MPs by body weight. Trophic transfer occurred between prey and predator for rockfish, but higher concentrations in full stomachs compared with empty ones suggested rapid excretion of ingested MPs. Collectively, our findings suggested the movement of MP through marine food webs is facilitated by species-specific mechanisms, with contamination susceptibility a function of species biology, not trophic position. Furthermore, the statistical methods we employ, including machine learning for classifying unknown particles and a probabilistic way to account for background contamination, are universally applicable to the study of microplastics. Our findings advance understanding of how MPs enter and move through aquatic food webs, suggesting that lower-trophic-level animals are more at risk of ingesting >100-μm MPs, relative to higher-trophic-level animals. Our work also highlights the need to advance the study of <100-μm MPs, which are still poorly understood and may need to be considered separately in ecological risk assessments.

Impacts of terrestrial input on the distribution characteristics of microplastics in the East China Sea characterized by chromophoric dissolved organic matter (CDOM) analysis

Large quantities of microplastics are found in the East China Sea (ECS), however, the impacts of complicated terrestrial input on the distribution characteristics of microplastics have not been studied. Hence, we aimed to characterize the microplastic distribution in the ECS combined with the fluorescence characteristics of chromophoric dissolved organic matter (CDOM), a sensitive technique to trace terrestrial substances in seawater. The average microplastic abundance in the surface seawater of ECS was 34.73 ± 4.05 items/m³ and sites in the north ECS had a higher microplastic abundance (55.90 ± 2.47 items/m³) than those in the southern region (11.22 ± 4.01 items/m³), due to its proximity to the Yangtze River estuary and Hangzhou Bay. Polyethylene (PE, 44.2 %) was the most abundant microplastic type in the northern region, whereas polyethylene terephthalate (PET, 28.4 %) had a higher proportion in the south ECS. Besides, sites in the north ECS had a higher diversity index of microplastics, suggesting various sources of microplastic pollution. Interestingly, a stronger correlation with the diversity index was found for protein-like component C3 (R² = 0.56) in northern regions compared to fulvic-like component C1 (R² = 0.32) and humic-like component C2 (R² = 0.28), suggesting the significant impact of anthropogenic discharge. Moreover, no correlation between fluorescence components and microplastic diversity index was found in the south ECS, indicating that CDOM can reflect the impact range of terrestrial input on the distribution characteristics of microplastics. This research might be useful in assessing and reducing the impact of terrestrial input on the distribution characteristics of microplastics in the ECS.

Occurrence of microplastics in gastrointestinal tract of fish from the Gulf of Guinea, Ghana

Over the past decades, there has been a growing concern about microplastics pollution in global aquatic habitats and its potential impact on human health. This study was carried out to determine the presence of microplastics in fish of economic importance in Ghana. Microplastics were found to be abundant in all investigated samples, with 68 % of the fishes contaminated with microplastics and a total of 133 plastic items identified in the fish. The presence of fibers, black coloured particles, and microplastics in the size range of 0.5-1.0 mm was the most abundant in the samples examined. Three polymers specifically, polyethylene, polyvinyl acetate, and polyamide were identified in the study. The presence of microplastics in the fishes investigated may pose severe ecological and health concerns, and hence comprehensive policies targeted at preventing plastic pollution of Ghana's maritime environment is warranted.

Anthropogenic particles in coypu (Myocastor coypus; Mammalia, Rodentia)' faeces: first evidence and considerations about their use as track for detecting microplastic pollution

Anthropogenic plastic litter is widespread in all environments, with particular emphasis on aquatic habitats. Specifically, although freshwater mammals are important as they are at the top of food web, research mainly focus on marine animals, while only few studies have been carried out on freshwater mammals. The main gap is that microplastics (MP) are completely understudied in freshwater mammals. Here, we reported the first evidence of the presence of anthropogenic particles (including MP) in coypu (Myocastor coypus)' faeces. Coypu is a rodent mammal inhabiting rivers and wetland areas, and we discussed our preliminary data suggesting the use of these tracks as possible future bioindicator of MP pollution in wetlands and freshwaters. We collected 30 coypu's faeces in "Torre Flavia wetland" nature reserve. Then, in laboratory, faeces were digested in 30 ml hydrogen peroxide (30%) for a week a 20 °C and analysed under stereoscope. All the suspected found MP were isolated in a petri dish, using FT-IR analysis to confirm the polymers. Overall, we recorded 444 natural and anthropogenic particles with most of items being fibres. FT-IR analysis of the 10% of the particles recovered revealed that 72% of them was not MP (mainly, polyethylene, polyethylene terephthalate, and polyamide). Also, the number of anthropogenic particles is not correlated with the faecal weight. Given that alien species, such as coypu, are widespread species, our results might have a great importance as these species and MP in faecal tracks may be used as undirect proxy of environmental bioavailability of MP pollution.

Spatial distribution and risk assessments due to the microplastics pollution in sediments of Karnaphuli River Estuary, Bangladesh

Microplastics (MPs) have become an emerging global pollutant due to their widespread dispersion and potential threats to marine ecosystems. However, studies on MPs in estuarine and coastal ecosystems of Bangladesh are very limited. Here, we conducted the first study on abundance, distribution, characteristics, and risk assessment of microplastics in the sediment of Karnaphuli River estuary, Bangladesh. Microplastic particles were extracted from sediments of 30 stations along the estuary by density separation and then enumerated and characterized using a stereomicroscope and Fourier Transform Infrared (FT-IR) spectroscopy. In the collected sediment of the Karnaphuli River estuary, the number of MPs varied from 22.29 to 59.5 items kg^-1 of dry weight. The mean abundance was higher in the downstream and left banks of the estuary, whereas the predominant shape, colour, and size of MPs were films (35%), and white (19%), and 1-5 mm (30.38%), respectively. Major polymer types were polyethylene terephthalate, polystyrene, polyethylene, cellulose, and nylon. MPs were found to pose risks (low to high) in the sediment of the estuary, with the highest risk occurring at one station near a sewage outlet, according to the results of risk analyses using the pollution risk index, polymer risk index (H), contamination factors, and pollution load index (PLI). The single value index, PLI, clearly demonstrated that all sampling sites were considerably polluted with microplastics (PLI > 1). H values showed toxic polymers, even in lower proportions, possess higher polymeric hazard scores and vice versa. This investigation uncovered new insights on the status of MPs in the sediments of the Karnaphuli River estuary, laying the groundwork for future research and control of microplastic pollution and management.

The patterns of trophic transfer of microplastic ingestion by fish in the artificial reef area and adjacent waters of Haizhou Bay

Plastic pollution has become a threat to the global marine environment. Many studies have shown that marine organisms are at risk of plastic ingestion, but there is still a lack of relevant research in the artificial reef area and adjacent waters of Haizhou Bay, located in the western Yellow Sea. The study of MPs will provide useful information for MPs pollution in the artificial reef food webs, as well as the understanding of MPs trophic transfer by reef fish. In this study, we quantified plastic ingestion by marine fish in artificial reef areas and adjacent waters (Natural area, NA; Aquaculture area, AA; Estuary area, EA; Artificial reefs area, AR and Comprehensive effective area, CEA) and analysed the related possible influencing factors. Of the 146 fish samples examined, 100% of fish ingested plastics, and 98.9% of these particles were microplastics (MPs) (<5 mm), with 3.00 ± 2.63 pieces/fish. The main types and colours of MPs were fibre (95.9%) and blue (84%). The MP quantity of AR and AA were significantly higher than that of CEA (P < 0.05) and there is no significant difference among other habitats. The MP ingestion by pelagic fishes was significantly lower than that of demersal fishes (P < 0.05). MP ingestion by omnivores was significantly higher than that by carnivores and planktivores (P < 0.05). The body length (body weight) of four species (Larimichthys polyactis: 17.7-16.7 cm (16.01-59.41 g); Collichthys lucidus: 8.1-14.3 cm (19.65-56.92 g); Tridentiger barbatus: 5.9-9.2 cm (3.37-19.1 g); Cynoglossus joyneri: 10.1-18.7 cm (5-45 g)) had no significant correlation with MP ingestion (P > 0.05). Our results showed that MPs in this region are ubiquitous (i.e., the MP ingestion rate was as high as 100%). We infer that there is a transfer mechanism in MPs from pelagic to benthic fish in this area, and there is weak biomagnification with the trophic transfer of the food chain (TMF = 1.62). However, more practical studies still need to verify whether MPs are actually transferred to humans through trophic transfer from the marine food web.

Microplastic pollution in the environment and organisms of Xiangshan Bay, East China Sea: An area of intensive mariculture

Microplastic (MP) pollution in oceans is an emerging environmental problem that poses ecological risks for marine ecosystems. Based on the abundance, distribution, and characteristics of microplastics (MPs) in surface water, sediment, and organisms, MP sources, pollution, trophic transfer, and ecological risk in Xiangshan Bay, an area of intensive mariculture in East China Sea, were assessed in this study. MPs were prevalent in the environment and organisms, with overall abundances at a low-medium level compared with the levels in the coastal areas. In water, MPs were more abundant in the inner bay (0.32 items m^-3), which is a more significant source of MPs with intensive mariculture than the central (0.09 items m^-3) and outer bays (0.07 items m^-3). The narrow and land-enclosed inner bay, with weak hydrodynamics for water exchange, retained MPs, thus increasing their abundance. The ecological risk of MPs in water was at a low-moderate level. The MP abundance in sediment did not vary significantly among the three regions of the bay. The morphological characteristics and polymers of the MPs differed in sediment from those in water, which was related to their diverse environmental redistribution routes. MP abundance ingested by organisms were related to their biological features and foraging habits. Overall, fish ingested more MPs than crustaceans, bivalves, and cephalopods, while zooplankton ingested the minimal MPs. Filter feeders ingested less MPs, with a preference for smaller particles than predators. MPs did not show trophic transfer behavior in organisms. Additionally, MPs ingested by infauna showed similar morphological and chemical characteristics compared to sediment at the point of organism residence, whereas MPs ingested by pelagic species were dissimilar to those in surface water. Our findings provide information for understanding MP pollution, source tracing, trophic transfer, and ecological risk assessment in coastal ecosystems.

Microplastic uptake and gut retention time in Japanese anchovy (Engraulis japonicus) under laboratory conditions

To explore the impact of microplastic (MP) pollution on planktivorous fish, we examined the uptake and retention of MPs by Japanese anchovy (Engraulis japonicus) under laboratory conditions. MP uptake was size selective in adult anchovy-0.3-mm MPs were taken up in significantly larger amounts than 0.85-mm MPs-but not in juveniles. There were no significant differences in the uptake of MPs of three different colors, suggesting that anchovy do not select for MP coloration. More than 90% of the MPs were excreted within 20 h of ingestion, indicating that MP retention time is similar to the processing time of food items. Our findings suggest that Japanese anchovy tend to take up MPs that are equivalent in size to prey items, but that the impacts of MP ingestion are likely to be limited under the current state of oceanic MP contamination.

Distribution and translocation of micro- and nanoplastics in fish

Microplastics (MPs) and nanoplastics (NPs) are regarded as emerging particulate contaminants. Here, we first summarize the distribution of plastic particles in fish. Field investigations verify the presence of various kinds of fibrous, spherical, and fragmentary MPs in fish gastrointestinal tract and gills, and specifically in muscle and liver. Laboratory works demonstrate that NPs even penetrate into blood vessels of fish and pass onto next generations. Second, we systematically discuss the translocation ability of MPs and NPs in fish. MPs can enter early-developing fish through adherence, and enter adult fish internal organs by intestine absorption or epidermis infiltration. NPs can not only penetrate into fish embryo blastopores, but also reach adult fish internal organs through blood circulation. Third, the cellular basis for translocation of plastic particles, NPs in particular, into cells are critically reviewed. Endocytosis and paracellular penetration are two main pathways for them to enter cells and intercellular space, respectively. Finally, we compare the chemical and physical properties among various particular pollutants (MPs, NPs, settleable particulate matters, and manufactured nanomaterials) and their translocation processes at different biological levels. In future studies, it is urgent to break through the bottleneck techniques for NPs quantification in field environmental matrix and organisms, re-confirm the existence of MPs and NPs in field organisms, and develop more detailed translocating mechanisms of MPs and NPs by applying cutting-edge tracking techniques.

Microplastics in different tissues of caught fish in the artificial reef area and adjacent waters of Haizhou Bay

In recent years, the microplastics (MPs) pollution in the offshore of microplastics has gradually become a concerning topic, and the understanding the accumulation of MPs in different tissues of organisms is also an important aspect. MPs can easily affect target tissues and transport related chemicals to humans through the food chain. MPs in the gills and guts of fish in the artificial reef area of Haizhou Bay and adjacent waters were detected in this study. The results showed that MPs were ubiquitous in the gills and guts of 26 species, with average quantities of 3.54 ± 2.14 pieces/fish and 3.00 ± 2.63 pieces/fish, respectively. More than 99% of the plastics were MPs that were less than 5 mm in diameter, with blue fiber being the most common. The number and quantity of MPs in gills were higher than those in guts in different habitat types, living water layers and feeding habits of fish. At the community level, as the body length and body weight increased, the quantity of MPs in the gills and guts showed a slight decreasing trend, and the correlation was not strong (P > 0.05). With increasing trophic levels (TLs), MPs were biomagnified in the guts (Trophic magnification factor, TMF = 1.37), but no change occurred in the gills (TMF = 1.00). We believe that biomagnification of MPs should be obtained by comparing the quantity of MPs in whole organisms rather than only in specific tissues before such conclusions can be defined. We recommend that periodic marine monitoring programs be implemented, as well as research into smaller MPs and even nanoplastics, to assess from the perspective of water, sediments, organisms and ecotoxicology, which will provide useful information for MPs pollution in artificial reefs and help to improve the MPs pollution database in China.

Microplastics in mangroves and coral reef ecosystems: a review

Microplastic pollution has recently been identified as a major issue for the health of ecosystems. Microplastics have typically sizes of less than 5 mm and occur in various forms, such as pellets, fibres, fragments, films, and granules. Mangroves and coral reefs are sensitive and restricted ecosystems that provide free ecological services such as coastal protection, maintaining natural cycles, hotspots of biodiversity and economically valuable goods. However, urbanization and industrial activities have started contaminating even these preserved ecosystems. Here we review sources, occurrence, and toxicity of microplastics in the trophic levels of mangrove and coral reef ecosystems. We present detection methods, such as microscopic identification and spectroscopy. We discuss mitigating measures that prevent the entry of microplastics into the marine environment.

Microplastic pollution in Larimichthys polyactis in the coastal area of Jiangsu, China

We investigated microplastics (MPs) pollution in 349 Larimichthys polyactis specimens from the coastal area of Jiangsu Province, China. The MP abundance in L. polyactis was 1.03 ± 1.04 items/individual and 0.95 ± 0.92 items/10 g (wet weight). The MP abundance in specimens from the Haizhou Bay fishing ground was slightly higher than that in specimens from the Lvsi fishing ground. Spearman's correlation showed that MP abundance was positively correlated with body length when expressed as items/individual, but not items/10 g. The abundance in the gastrointestinal tract was slightly higher than that in the gills, but the differences were not significant for either measurement index. The MPs predominantly ingested by L. polyactis were <1 mm, fibrous, blue and had a cellophane composition. The MP pollution in L. polyactis in the coast of Jiangsu Province is at a medium to low level, as compared with other regions of China.

Microplastics in different tissues of a pelagic squid (Dosidicus gigas) in the northern Humboldt Current ecosystem

Microplastics (MPs) found in marine invertebrates have aroused great concern, but MP ingestion by cephalopods is rare. To evaluate MP contamination in commercially important pelagic squids, we examined the abundance and characteristics of MPs in the gill, intestine, and stomach of jumbo squid Dosidicus gigas (30.9 to 65.0 cm mantle length), collected from the northern Humboldt Current. The average abundance ranged from 4.0 to 7.4 items/individual and 0.2 to 0.7 items/g wet weight for the three tissues. The MPs were sized 80.75 to 4632.27 μm, with larger MPs generally found in the stomach. The majority of MPs were fibrous in shape, blue or black-gray in color, and cellophane in composition. These results revealed the MP distribution in D. gigas and could be driven by its movement pattern and habitat use. Furthermore, this study provides evidence that adherence to gills is probably an alternative means by which pelagic squid accumulate MPs.

Microplastic and artificial cellulose microfibers ingestion by reef fishes in the Guarapari Islands, southwestern Atlantic

This study investigated the ingestion of microplastics and artificial cellulose particles by 103 specimens belonging to 21 reef fish species from the southwestern Atlantic. Specimens of six species had ingested microplastics and artificial cellulose particles, while those of another three species had ingested only one type of material. In our samples, man-made cellulose fibers were more common than microplastics. The tomtate grunt, Haemulon aurolineatum, ingested more particles than any of the other species. Overall, transparent particles were predominant, and polyamide was the most common plastic material. Household sewage, fishery activity, and navigation appear to be the principal sources of the artificial particles ingested by the reef fishes. Our results provide an important database on oceanic contamination by microplastics and artificial cellulose particles. Understanding this impact on tropical reef fish will contribute to the development of strategies to mitigate pollution by anthropogenic debris in reef systems.

Interactions Between Microplastics and Heavy Metals in Aquatic Environments: A Review

Microplastics (MPs), tiny particles broken down from larger pieces of plastics, have accumulated everywhere on the earth. As an inert carbon stream in aquatic environment, they have been reported as carriers for heavy metals and exhibit diverse interactive effects. However, these interactions are still poorly understood, especially mechanisms driving these interactions and how they pose risks on living organisms. In this mini review, a bibliometric analysis in this field was conducted and then the mechanisms driving these interactions were examined, especially emphasizing the important roles of microorganisms on the interactions. Their combined toxic effects and the potential hazards to human health were also discussed. Finally, the future research directions in this field were suggested. This review summarized the recent research progress in this field and highlighted the essential roles of the microbes on the interactions between MPs and heavy metals with the hope to promote more studies to unveil action mechanisms and reduce/eliminate the risks associated with MP presence.