The vertical distribution and biological transport of marine microplastics across the epipelagic and mesopelagic water column

The microscopic threat with a macroscopic impact: Microplastics along the southeast Florida reef tract

Microplastics decrease oceanic water quality and negatively impact marine life. This research quantified and classified marine plastic pollution along the Southeast Florida Reef Tract (SEFRT) to estimate the risk of microplastic damage to corals in this region. Surface and bottom water samples were collected at seven sites along the SEFRT over the course of six months and were analyzed for microplastic content. FTIR spectrophotometry was used to evaluate microplastic composition. Overall, seven plastic polymers were found across a total of 1204 microplastic items. Five contaminants were also identified, indicating that microplastics may be congregators of these hazardous contaminants. Significantly more total plastics were found in surface samples than in bottom samples, but plastic quantities were not significantly different when month, depth, and location were combined. Plastics were determined to have entered the ocean from multiple sources; in order to protect vulnerable reef ecosystems in this area, a two-factor approach is necessary to halt the release of microplastics into the ocean, including widespread plastic clean-up efforts and improvements to plastic waste management.

Fabrication and Characterization of Ag-Graphene Nanocomposites and Investigation of Their Cytotoxic, Antifungal and Photocatalytic Potential

In the present study, we aimed to synthesize (Ag)_1-x(GNPs)_x nanocomposites in variable ratios (25% GNPs-Ag, 50% GNPs-Ag, and 75% GNPs-Ag) via an ex situ approach to investigate the incremental effects of GNPs (graphene nanoparticles) on AgNPs (silver nanoparticles). The prepared nanocomposites were successfully characterized using different microscopic and spectroscopic techniques, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet spectroscopy, and Raman spectroscopic analysis. For the evaluation of morphological aspects, shape, and percentage elemental composition, SEM and EDX analyses were employed. The bioactivities of the synthesized nanocomposites were briefly investigated. The antifungal activity of (Ag)_1-x(GNPs)_x nanocomposites was reported to be 25% for AgNPs and 66.25% using 50% GNPs-Ag against Alternaria alternata. The synthesized nanocomposites were further evaluated for cytotoxic potential against U87 cancer cell lines with improved results (for pure AgNPs IC₅₀: ~150 µg/mL, for 50% GNPs-Ag IC₅₀: ~12.5 µg/mL). The photocatalytic properties of the nanocomposites were determined against the toxic dye Congo red, and the percentage degradation was recorded as 38.35% for AgNPs and 98.7% for 50% GNPs-Ag. Hence, from the results, it is concluded that silver nanoparticles with carbon derivatives (graphene) have strong anticancer and antifungal properties. Dye degradation strongly confirmed the photocatalytic potential of Ag-graphene nanocomposites in the removal of toxicity present in organic water pollutants.

Low-Density Plastic Debris Dispersion beneath the Mediterranean Sea Surface

Plastic is a widespread marine pollutant, with most studies focusing on the distribution of floating plastic debris at the sea surface. Recent evidence, however, indicates a significant presence of such low density plastic in the water column and at the seafloor, but information on its origin and dispersion is lacking. Here, we studied the pathways and fate of sinking plastic debris in the Mediterranean Sea, one of the most polluted world seas. We used a recent Lagrangian plastic-tracking model, forced with realistic parameters, including a maximum estimated sinking speed of 7.8 m/d. Our simulations showed that the locations where particles left the surface differed significantly from those where they reached the seafloor, with lateral transport distances between 119 and 282 km. Furthermore, 60% of particles deposited on the bottom coastal strip (20 km wide) were released from vessels, 20% from the facing country, and 20% from other countries. Theoretical considerations furthermore suggested that biological activities potentially responsible for the sinking of low density plastic occur throughout the water column. Our findings indicate that the responsibility for seafloor plastic pollution is shared among Mediterranean countries, with potential impact on pelagic and benthic biota.

Correlative Light, Electron Microscopy and Raman Spectroscopy Workflow To Detect and Observe Microplastic Interactions with Whole Jellyfish

Many researchers have turned their attention to understanding microplastic interaction with marine fauna. Efforts are being made to monitor exposure pathways and concentrations and to assess the impact such interactions may have. To answer these questions, it is important to select appropriate experimental parameters and analytical protocols. This study focuses on medusae of Cassiopea andromeda jellyfish: a unique benthic jellyfish known to favor (sub-)tropical coastal regions which are potentially exposed to plastic waste from land-based sources. Juvenile medusae were exposed to fluorescent poly(ethylene terephthalate) and polypropylene microplastics (<300 μm), resin embedded, and sectioned before analysis with confocal laser scanning microscopy as well as transmission electron microscopy and Raman spectroscopy. Results show that the fluorescent microplastics were stable enough to be detected with the optimized analytical protocol presented and that their observed interaction with medusae occurs in a manner which is likely driven by the microplastic properties (e.g., density and hydrophobicity).

Sonopiezoelectric Nanomedicine and Materdicine

Endogenous electric field is ubiquitous in a multitude of important living activities such as bone repair, cell signal transduction, and nerve regeneration, signifying that regulating the electric field in organisms is highly beneficial to maintain organism health. As an emerging and promising research direction, piezoelectric nanomedicine and materdicine precisely activated by ultrasound with synergetic advantages of deep tissue penetration, remote spatiotemporal selectivity, and mechanical-electrical energy interconversion, have been progressively utilized for disease treatment and tissue repair by participating in the modulation of endogenous electric field. This specific nanomedicine utilizing piezoelectric effect activated by ultrasound is typically regarded as "sonopiezoelectric nanomedicine". This comprehensive review summarizes and discusses the substantially employed sonopiezoelectric nanomaterials and nanotherapies to provide an insight into the internal mechanism of the corresponding biological behavior/effect of sonopiezoelectric biomaterials in versatile disease treatments. This review primarily focuses on the sonopiezoelectric biomaterials for biosensing, drug delivery, tumor therapy, tissue regeneration, antimicrobia, and further illuminates the underlying sonopiezoelectric mechanism. In addition, the challenges and developments/prospects of sonopiezoelectric nanomedicine are analyzed for promoting the further clinical translation. It is earnestly expected that this kind of nanomedicine/biomaterials-enabled sonopiezoelectric technology will provoke the comprehensive investigation and promote the clinical development of the next-generation multifunctional materdicine.

Physical processes matters! Recommendations for sampling microplastics in estuarine waters based on hydrodynamics

Monitoring the abundance and characteristics of microplastics in estuarine waters is crucial for understanding the fate of microplastics at the land-sea continuum, and for developing policies and legislation to mitigate associated risks. However, if protocols to monitor microplastic pollution in ocean waters or beach sediments are well established, they may not be adequate for estuarine environments, due to the complex 3D hydrodynamics. In this note, we review and discuss sampling methods and strategies in relation to the main environmental forcing, estuarine hydrodynamics, and their spatio-temporal scales of variability. We propose recommendations about when, where and how to sample microplastics to capture the most representative picture of microplastic pollution. This note opens discussions on the urgent need for standardized methods and protocols to routinely monitor microplastics in estuaries which should, at the same time, be easily adaptable to the different systems to ensure consistency and comparability of data across different studies.

Protein-plastic interactions: The driving forces behind the high affinity of a carbohydrate-binding module for polyethylene terephthalate

Polyethylene terephthalate (PET) waste is a common pollutant in the environment, mainly due to resistance of the plastic to bio-degradation. Nevertheless, hydrolytic enzymes have been identified with activity on this substrate, which are continually being engineered to increase activity. Some insoluble biological polymers are degraded by enzymes with a multi-domain architecture, comprising of a catalytic domain, and a substrate-binding domain, such as a carbohydrate-binding module (CBM). Enzymes that degrade PET have been shown to have a higher activity when fused with these CBMs, indicating a promising route for engineering better enzymes for plastic bioprocessing. However, no detailed study of the affinity and binding mechanism of these domains on PET has yet been made. Here, we perform an in depth analysis of a binding domain from CBM family 2 on PET, showing that the affinity of the protein for the plastic is highly dependent on temperature and crystallinity of the plastic. We also investigate the mechanism of the interaction, and show how affinity may be engineered in both directions. CBM affinity for other synthetic polymers is also demonstrated for the first time. Our results demonstrate that the substrate affinity of fusion enzymes with binding modules can be tuned to the desired level.

Macroecotoxicological approaches to emerging patterns of microplastic bioaccumulation in crabs from estuarine and marine environments

Despite the increasing plastic discharge into the environment, few articles have dealt with the macroecological implications of microplastics (MPs) bioaccumulation on organisms. We performed a meta-analysis of MPs accumulation in true crabs and pseudocrabs worldwide and made use of macroecotoxicological approaches to know if: I) functional traits influence the bioaccumulation of MPs in the tissues of crabs; II) there is a latitudinal pattern of MPs bioaccumulation; III) there are tissues that can accumulate more MPs; IV) crabs can sort particles according to size, color, shape and type. Our results showed that functional traits influence the accumulation of MPs. Smaller crabs in size and weight and with shorter lifespans tended to exhibit more plastic particles. According to the environment, estuarine crabs from the intertidal and muddy substrates held more MPs. Also, burrowers exhibited significantly more particles in the tissues than omnivorous crabs. Besides, we recorded that crabs from low latitudes tended to exhibit more plastic particles, probably because of the mangroves' location that acts as traps for MPs. Non-human-consumed crabs accumulated significantly more MPs than human-consumed ones. Considering the tissues, gills were prone to accumulate more debris than the digestive tract, but without significant differences. Finally, colorless fibers of 1-5 mm of PA, PP and PET were the predominant characteristics of MPs, suggesting that crabs accumulated denser types but did not sort plastic according to color. These results indicate that functional traits might influence the accumulation of MPs and that there are coastal regions and geographical areas where crabs tend to accumulate more MPs. Analyzing MPs accumulation patterns with macroecological tools can generate information to identify the most affected species and define priorities for monitoring and implementing actions toward reducing plastic use globally.

Controllable preparation of mesoporous spike gold nanocrystals for surface-enhanced Raman spectroscopy detection of micro/nanoplastics in water

Microplastics and nanoplastics are emerging classes of environmental contaminants that pose significant threats to human health. In particular, small nanoplastics (<1 μm) have drawn considerable attention owing to their adverse effects on human health; for example, nanoplastics have been found in the placenta and blood. However, reliable detection techniques are lacking. In this study, we developed a fast detection method that combines membrane filtration technology and surface-enhanced Raman spectroscopy (SERS), which can simultaneously enrich and detect nanoplastics with sizes as small as 20 nm. First, we synthesized spiked gold nanocrystals (Au NCs), achieving a controlled preparation of thorns ranging from 25 nm to 200 nm and regulating the number of thorns. Subsequently, mesoporous spiked Au NCs were homogeneously deposited on a glass fiber filter membrane to form an Au film as a SERS sensor. The Au-film SERS sensor achieved in-situ enrichment and sensitive SERS detection of micro/nanoplastics in water. Additionally, it eliminated sample transfer and prevented the loss of small nanoplastics. Using the Au-film SERS sensor, we detected 20 nm to 10 μm standard polystyrene (PS) microspheres with a detection limit of 0.1 mg/L. We also realized the detection of 100 nm PS nanoplastics at the 0.1 mg/L level in tap water and rainwater. This sensor provides a potential tool for rapid and susceptible on-site detection of micro/nanoplastics, especially small-sized nanoplastics.

Influencing factors for microplastic intake in abundant deep-sea lanternfishes (Myctophidae)

Plastic debris is ubiquitous in the hydrosphere. Yet, we lack an understanding of contamination among deep-sea species and primarily how each trait can influence microplastic intake. We investigated microplastic contamination in the digestive tract of hyper-abundant mesopelagic lanternfishes (n = 364 individuals) from the Southwestern Tropical Atlantic, captured from 90 to 1000 m depth. Overall, microplastics were detected in most individuals analysed (frequency of occurrence = 68 %). Large microplastics, mostly of a filamentous shape were the most frequent, followed by smaller fragments and foams. Microplastics made of high-density polymers (PET, PVC, PA, SBR rubber) were more prevalent than low-density ones (PE, EVA and PBD rubber), especially under deeper layers. Larger microplastics were detected in lanternfishes captured off the northeastern Brazilian coast (mean 0.88 ± SE 0.06 mm) compared to those from around the Rocas Atoll and Fernando de Noronha Archipelago (0.70 ± 0.07 mm; p≤ 0.05), ∼350 km from the continent. Moreover, lanternfishes that migrate from the upper mesopelagic (200-500 m) to the epipelagic layers (<200 m) had simultaneously the highest intake and the smallest particles (1.65 ± 0.17 particles individual^-1 and 0.55 ± 0.07 mm; p≤ 0.05). Biological mediated transport of microplastics from the epipelagic to the mesopelagic waters was evinced, but fishes foraging in shallower layers had the lowest intake (1.11 ± 0.10 part. ind.^-1; p≤ 0.05). Furthermore, the jaw length was positively associated with an increment in microplastic intake (Incidence Rate Ratio = 1.1; p≤ 0.05). The lanternfishes that preferably prey upon fish larvae are more prone to microplastic intake than their counterparts, which forage mostly on crustaceans and gelatinous zooplankton (p≤ 0.05).

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.

A baseline assessment of the relationship between microplastics and plasticizers in sediment samples collected from the Barcelona continental shelf

It has been suggested that the seafloor may be a sink for the plastic debris that enters the ocean. Therefore, the collection of data in the seafloor sediments regarding the co-presence of microplastics (MPs) and contaminants associated to plastic is considered a relevant topic. However, the number of studies addressing their possible correlation in this environment is still limited, and very little is known about the mechanisms that determine the release of plastic additives from plastic items. Starting from this basis, we investigated the presence of MPs and eleven phthalic acid esters (PAEs) in the continental shelf offshore Barcelona. Following a shelf-slope continuum approach, we sampled sediments from five stations, and we performed analysis by means of infrared micro spectroscopy (µFTIR) and liquid chromatography tandem mass spectrometry (LC-MS/MS). MPs were found to range from 62.0 to 931.1 items/kg d.w. with maximum concentration in the submarine canyon Besòs and at the highest depth. Moreover, different trends in the size distribution of fibers and non-fibers were observed, indicating the occurrence of a size dependent selection mechanism during transport and accumulation. PAEs resulted comprised between 1.35 to 2.41 mg/kg with Di(2-ethylhexyl)phthalate (DEHP) the most abundant congeners (1.04 mg/kg). Statistical analysis revealed no correlation between the Σ₁₁PAEs and the total MPs concentration, but correlation between DEHP and fibers (σ = 0.667, p = 0,037), that resulted both correlated to the distance to the coast (ρ = 0.941 with p = 0,008 and ρ = 0.673 with p = 0.035, respectively).

Abundance and distribution of microplastics in surface waters of the Kattegat/ Skagerrak (Denmark)

Microplastics (MPs) are ubiquitous pollutants in the ocean, and there is a general concern about their persistence and potential effects on marine ecosystems. We still know little about the smaller size-fraction of marine MPs (MPs <300 μm), which are not collected with standard nets for MPs monitoring (e.g., Manta net). This study aims to determine the concentration, composition, and size distribution of MPs down to 10 μm in the Kattegat/Skagerrak area. Surface water samples were collected at fourteen stations using a plastic-free pump-filter device (UFO sampler) in October 2020. The samples were treated with an enzymatic-oxidative method and analyzed using FPA-μFTIR imaging. MPs concentrations ranged between 11 and 87 MP m^-3, with 88% of the MPs being smaller than 300 μm. The most abundant shape of MPs were fragments (56%), and polyester, polypropylene, and polyethylene were the dominant synthetic polymer types. The concentration of MPs shows a significant positive correlation to the seawater density. Furthermore, there was a tendency towards higher MPs concentrations in the Northern and the Southern parts of the study area. The concentration of MPs collected with the UFO sampler was several orders of magnitude higher than those commonly found in samples collected with the Manta net due to the dominance of MP smaller size fractions. Despite the multiple potential sources of MPs in the study area, the level of MPs pollution in the surface waters was low compared (<100 MP m^-3) to other regions. The concentrations of MPs found in the studied surface waters were six orders of magnitude lower than those causing negative effects on pelagic organisms based on laboratory exposure studies, thus is not expected to cause any impact on the pelagic food web.

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.

Impact of face mask microplastics pollution on the aquatic environment and aquaculture organisms

Microplastic pollution in our environment, especially water bodies is an emerging threat to food security and human health. Inevitably, the outbreak of Covid-19 has necessitated the constant use of face masks made from polymers such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene, or polyester which eventually will disintegrate into microplastic particles. They can be broken down into microplastics by the weathering action of UV radiation from the sun, heat, or ocean wave-current and precipitate in natural environments. The global adoption of face masks as a preventive measure to curb the spread of Covid-19 has made the safe management of wastes from it cumbersome. Microplastics gain access into aquaculture facilities through water sources and food including planktons. The negative impacts of microplastics on aquaculture cannot be overemphasized. The impacts includes low growth rates of animals, hindered reproductive functions, neurotoxicity, low feeding habit, oxidative stress, reduced metabolic rate, and increased mortality rate among aquatic organisms. With these, there is every tendency of microplastic pollution to negatively impact fish production through aquaculture if the menace is not curbed. It is therefore recommended that biodegradable materials rather than plastics to be considered in the production of face mask while recycle of already produced ones should be encouraged to reduce waste.

Microplastic in northern anchovies (Engraulis mordax) and common murres (Uria aalge) from the Monterey Bay, California USA - Insights into prevalence, composition, and estrogenic activity

Microplastic (particle size <5 mm) is considered an emerging threat to the marine environment, yet data are limited for coastal ecosystems. To provide information related to microplastic in a coastal system, we used alkaline tissue digestion and Raman spectroscopy to quantify the prevalence and composition (e.g. fiber, fragment, foam, etc.) of anthropogenic microparticles in the digestive tracts of northern anchovies (Engraulis mordax, anchovy, n = 24), and common murres (Uria aalge, murre, n = 19) from the Monterey Bay, California USA. We also determined microplastic prevalence and composition in seawater (n = 12 17-h sampling periods representing ∼46,000 L sampled) from two Monterey Bay intake systems (Moss Landing, CA and Santa Cruz, CA USA). Microparticles recovered from murre digestive tracts were assessed for estrogenic activity using an in-vitro estrogen receptor activation assay. Suspected anthropogenic microparticles based on visual characteristics were recovered from all sample types with ∼2 particles per 1000 L from the seawater sampling periods, 58% prevalence in anchovies, and 100% prevalence in murres. Across samples of seawater, anchovies, and murres, the most abundant microparticle type found were fibers (78%), followed by fragments (13%), foam (6%), film (2%), and beads (1%). Raman spectroscopy identified 57% of microparticles (excluding dye-prominent and unknown) as plastic (synthetic, semi-synthetic, or blends). Almost one quarter (23%) of the murre digestive tracts contained microparticles that exhibited estrogenic activity. Our study describes the widespread occurrence, composition, and potential estrogenic activity of microplastic in the Monterey Bay and provides important information to aid in the understanding of microplastic contamination in coastal systems.

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.

A Raman spectral reference library of potential anthropogenic and biological ocean polymers

Microplastics have been extensively documented in marine ecosystems and food webs with devastating impacts. To solve this global crisis, identifying the polymer composition is key for resolving the material origin, geographic source, and ecosystem life cycle of ocean plastics. Visually based techniques, importantly, are not diagnostic. Raman spectroscopy is an increasingly preferred identification method for its accuracy and reduced likelihood of misinterpretation, though it can be inaccessible due to cost of paywalled spectral libraries and availability of relevant polymer spectra for comparison. Here, we provide an open-access reference library of high-quality, broad-spectrum Raman spectra of major polymer categories germane to marine environments. The library includes high-quality spectra from: (a) pristine anthropogenic polymers newly sourced from manufacturers (n = 40), (b) weathered anthropogenic polymers collected from used consumer, beachcast, agricultural, and fishery sources (n = 22), and (c) biological polymers representing diverse marine taxa, trophic levels, and tissues (n = 17). We hope this reference library can help this rapidly expanding scientific community and facilitate progress in the global plastic pollution crisis.

Microplastic pollution in soils, plants, and animals: A review of distributions, effects and potential mechanisms

Increasing production of synthetic plastics and poor management of plastic wastes have dramatically increased the amount of plastics in the environment. In 2014, at the first United Nations Environment Assembly, marine plastic waste pollution was listed as one of the 10 most pressing environmental issues. In addition, there is much plastic waste in terrestrial ecosystems due to substantial residues from agricultural mulching and packing. As a recently recognized pollutant, microplastics (MPs) have attracted significant attention from the public and various governments. Concentrations of MPs in the environment vary among locations, from <100 to >1 × 10⁶ particles per cubic meter. Many studies have addressed the impacts and potential mechanisms of MPs on the environment and organisms. Humans and other organisms can ingest or carry MPs in a variety of passive ways and these MPs can have a range of negative effects on metabolism, function, and health. Additionally, given their large surface area, MPs can sorb various pollutants, including heavy metals and persistent organic pollutants, with serious implications for animals and human wellbeing. However, due to their complexity and a lack of accurate determination methods, the systematic impacts of MP pollution on whole foodwebs are not clearly established. Therefore, this review summarizes current research advances in MP pollution, particularly the impact of MPs on soils, plants, and animals, and proposes potential future research prospects to better characterize MPs.

Comprehensive analysis of spatial distribution of microplastics in Rawal Lake, Pakistan using trawl net and sieve sampling methods

Occurrence of microplastics (MPs) in freshwater environments, particularly reservoir and lakes, is an emerging concern. There are limited studies in Pakistan on microplastic pollution in the lacustrine environments and those that exist do not provide sufficient information on the spatial distribution of MPs in offshore surface water. The aims of this study were to determine microplastic abundance in Rawal Lake, Pakistan and to ascertain if sampling methodology influences microplastic counts. Surface water samples were collected from 10 sites; 5 tributaries, 2 human settlement and 3 fishing and boating areas using two different sampling techniques: 100 μm mesh trawl and 20 L sample through a 45 μm mesh sieve. A significant difference was observed in the abundance of MPs across two methods with the sieve method yielding 2.8 ± 1.44 particles/L and trawl yielding 0.025 ± 0.024 particles/L. Tributaries and boating/fishing area had higher microplastic abundance than the residential area regardless of sampling method. Filaments were the dominant shape of MPs in both type of samples followed by fragments in trawl samples and films in sieved samples. Microbeads were only detected in trawl samples. MPs within size range 0.1-0.9 mm were mostly fragments (82%). MPs were diverse in colors with white/transparent and black MPs common. Polypropylene was the main type of microplastic in Rawal Lake (40-74%). Scanning Electron Microscopy (SEM) of MPs showed cracks, roughness and striations on the particles. Energy Dispersive Spectroscopy (EDS) detected heavy metals (Fe, Cu, Ni, Pb, Zn, Co and Cr) in MPs. Findings suggest that microplastic pollution in Rawal Lake may pose great risk to aquatic and human life through leaching of inherent/adsorbed heavy metals and therefore requires future investigation.

Maritime pollution in the Indian Ocean after the MV X-Press Pearl accident

The MV X-Press Pearl marine debacle severely affected the marine environment in the Indian Ocean. The objective of this study is to monitor environmental pollution along the west coast of Sri Lanka. Beach sand samples were collected from 40 locations. Visual and microscopic observations, plastic pellets pollution index (PPI), and degradation effects of plastic nurdles were examined. Chemical and thermal characteristics were investigated using Inductively Coupled Plasma Mass Spectrometric analysis (ICP-MS) and Fourier Transform Infra-Red Spectroscopic analysis (FTIR) analyses, respectively. Cylindrical-shaped plastic nurdles (>0.2 cm in size) were observed in off-white (mainly), yellow, and black colours. The white colour plastic nurdles change to yellow at 240 °C and black at 300 °C. Epamulla (PPI = 1940-3364) and Sarakkuwa (PPI = 2158-3466) beaches were recognized as the most contaminated beaches during the initial sampling (i.e., after six to eight days of the explosion of the vessel). Well-rounded small plastic nurdles (i.e., after one year of the disaster) can indicate degradation effects. FTIR results confirm (i) plastic nurdles as low-density polyethylene (LDPE) and (ii) alteration of the chemical composition of nurdles at a low temperature of 60 °C. In this case, a significant amount of microplastics have been added to the environment under the influence of UV irradiation and abrasion against beach sand. In addition, the presence of heavy metals (e.g., arsenic, cadmium, lead, and copper) in swash zone sediments is a great threat to marine animals and plants. Consequently, the ingestion of microplastics and heavy metals would be increased in a wide range of marine organisms and can be bio-accumulated in humans through seafood and salt.

Anthropogenic pollutants in Nephrops norvegicus (Linnaeus, 1758) from the NW Mediterranean Sea: Uptake assessment and potential impact on health

Anthropogenic pollution is considered one of the main threats to the marine environment, and there is an imperious need to assess its potential impact on ecologically and economically relevant species. This study characterises plastic ingestion and tissue levels of potentially toxic metallic elements in Nephrops norvegicus and their simultaneous levels in abiotic compartments from three locations of the Catalan coast (NW Mediterranean Sea). A multidisciplinary assessment of the health condition of N. norvegicus through condition indices, enzymatic biomarkers and histological techniques is provided, and its relationship with anthropogenic pollutant levels explored. Plastic fibres were commonly found in stomachs of N. norvegicus (85% of the individuals), with higher abundances (13 ± 21 fibres · ind^-1) in specimens captured close to Barcelona. The presence of long synthetic fibres in near-bottom waters, as well as the mirroring trends in abundance among locations for water and ingested plastics, suggest that uptake from water may be occurring potentially through suspension feeding. The spatial variability in the levels of metallic elements in N. norvegicus was poorly correlated to the variability in sediments. In any case, present levels in abdominal muscle are considered safe for human consumption. Levels of ingested plastics only showed significant, yet weak, correlations with glutathione S-transferase and catalase activities. However, no other health parameter analysed showed any trend potentially associated to anthropogenic pollutant levels. Neither the condition indices nor the histopathological assessment evidenced any signs of pathologic conditions affecting N. norvegicus. Thus, it was concluded that presently there is no evidence of a negative impact of the studied pollutants on the health condition of N. norvegicus in the studied grounds.

Hitchhiking into the Deep: How Microplastic Particles are Exported through the Biological Carbon Pump in the North Atlantic Ocean

Understanding residence times of plastic in the ocean is a major knowledge gap in plastic pollution studies. Observations report a large mismatch between plastic load estimates from worldwide production and disposal and actual plastics floating at the sea surface. Surveys of the water column, from the surface to the deep sea, are rare. Most recent work, therefore, addressed the "missing plastic" question using modeling or laboratory approaches proposing biofouling and degradation as the main removal processes in the ocean. Through organic matrices, plastic can affect the biogeochemical and microbial cycling of carbon and nutrients. For the first time, we provide in situ measured vertical fluxes of microplastics deploying drifting sediment traps in the North Atlantic Gyre from 50 m down to 600 m depth, showing that through biogenic polymers plastic can be embedded into rapidly sinking particles also known as marine snow. We furthermore show that the carbon contained in plastic can represent up to 3.8% of the total downward flux of particulate organic carbon. Our results shed light on important pathways regulating the transport of microplastics in marine systems and on potential interactions with the marine carbon cycle, suggesting microplastic removal through the "biological plastic pump".

Occurrence of Anthropogenic Debris in Three Commercial Shrimp Species from South-Western Ionian Sea

Deep Sea environments represent the final collector of anthropogenic debris mainly represented by both plastic and non-plastic materials with different size. This led to potential contamination of deep marine fauna due to direct and indirect ingestion, representing a potential hazard for the species itself and for the final consumer. In this framework, the present study explored the occurrence of anthropogenic debris in the gastrointestinal tract of three Decapoda species of high commercial and ecological value (Parapenaeus longirostris, Aristeus antennatus, and Aristaeomorpha foliacea) from south-western Ionian Sea. After morphometrical measurements and sex determination, the gastrointestinal tract of 136 specimens were extracted and then chemically digested. A total of 230 low density microparticles were isolated, with a high frequency of occurrence in all the analyzed species (76% in P. longirostris, 70% in A. antennatus, and 83% in A. foliacea) mainly represented by fibers (92.6%) with a size between 0.10 and 0.49 mm, and with a dominance of the blue color. The results of the present study report for the first time the anthropogenic debris presence in the studied Decapoda from south-western Ionian Sea, highlighting the necessity to broaden the knowledge about anthropogenic debris pollution status in Mediterranean deep-sea species.

Field measurements reveal exposure risk to microplastic ingestion by filter-feeding megafauna

Microparticles, such as microplastics and microfibers, are ubiquitous in marine food webs. Filter-feeding megafauna may be at extreme risk of exposure to microplastics, but neither the amount nor pathway of microplastic ingestion are well understood. Here, we combine depth-integrated microplastic data from the California Current Ecosystem with high-resolution foraging measurements from 191 tag deployments on blue, fin, and humpback whales to quantify plastic ingestion rates and routes of exposure. We find that baleen whales predominantly feed at depths of 50-250 m, coinciding with the highest measured microplastic concentrations in the pelagic ecosystem. Nearly all (99%) microplastic ingestion is predicted to occur via trophic transfer. We predict that fish-feeding whales are less exposed to microplastic ingestion than krill-feeding whales. Per day, a krill-obligate blue whale may ingest 10 million pieces of microplastic, while a fish-feeding humpback whale likely ingests 200,000 pieces of microplastic. For species struggling to recover from historical whaling alongside other anthropogenic pressures, our findings suggest that the cumulative impacts of multiple stressors require further attention.

A large diversity of organohalogen contaminants reach the meso- and bathypelagic organisms in the Bay of Biscay (northeast Atlantic)

Deep-sea ecosystems play a key role in the cycling and vertical transfer of matter and energy in oceans. Although the contamination of deep-sea demersal and benthic organisms by persistent organic pollutants has been proven, deep pelagic species have been far less studied. To fill these gaps, we studied the occurrence of a large variety of hydrophobic organic contaminants including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), legacy and alternative brominated flame retardants (BFRs) and per- and polyfluoroalkyl substances (PFASs) in crustaceans and fish species collected in the Bay of Biscay, northeast Atlantic. The results highlighted the global predominance of PCBs in fish, followed by OCPs, PFASs and PBDEs, with highly variable concentrations among species. Most of the chlorinated or brominated contaminants showed increasing concentrations with increasing δ¹⁵N values, while most PFASs showed inverse trends. The contaminant profiles and diagnostic ratios revealed species-specific metabolic capacities and peculiar contribution of highly-brominated BFRs.

Effects of plastic particles on aquatic invertebrates and fish - A review

This review summarises the current knowledge on the effects of microplastics and their additives on organisms living in the aquatic environment, particularly invertebrates and fish. To date, microplastics have been recognised to affect not only the behaviour of aquatic animals but also their proper development, causing variations in fertility, oxidative stress, inflammations and immunotoxicity, neurotoxicity, and changes in metabolic pathways and gene expression. The ability of microplastics to bind other xenobiotics and cause combined toxicity along side the effect of other agents is also discussed as well. Microplastics are highly recalcitrant materials in both freshwater and marine environments and should be considered extremely toxic to aquatic ecosystems. They are severely problematic from ecological, economic and toxicological standpoints.

Effects of organic matter on interaction forces between polystyrene microplastics: An experimental study

The aggregation and deposition processes of marine microplastics are extremely important in marine ecosystems. The main effect of these two physical processes is the transfer of surface microplastics to the deep sea, and the underlying kinetics can be significantly affected by the organic matter in the ocean. The morphology of and interaction force on 20-μm polystyrene microplastics in the presence of organic matter were studied by using environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM), respectively. Experiments were performed using organic matter of various concentrations, and the results showed that humic acid formed a translucent organic film around polystyrene microplastics. With increasing total organic content (TOC), the average overall size of the microplastic coated with biofilm increased up to 11 % (at a TOC of 50 mg/L) and then decreased slightly. The biofilm formed by humic acid decreases the repulsion force between two particles and thus could promote the aggregation process significantly. A modified formulation of eXtended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, describing the interaction force of microplastics with the influences of biofilms was proposed based on the measured results.

Method Development for Separation and Analysis of Tire and Road Wear Particles from Roadside Soil Samples

A comprehensive understanding of tire and road wear particles (TRWPs) and their detection and quantification in soils is still challenged by the lack of well-set standardized methods, inherent technological inconsistencies, and generalized protocols. Our protocol includes soil sampling, size separation, and organic matter removal by using hydrogen peroxide followed by density separation and analysis. In this context, roadside soil samples from different sites in Kansas and Ohio, USA, were collected and analyzed. Tire cryogrinds analogous to TRWPs were used to evaluate various density separation media, and collected particles more than 1 mm in size were then subjected to infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) to confirm TRWP presence. Particles smaller than 1 mm were Soxhlet extracted, followed by gas chromatography-mass spectrometry (GC-MS) to validate the presence of tire-related intermediates. SEM-EDX validated the presence of elemental combinations (S + Zn/Na) ± (Al, Ca, Mg, K, Si) attributed to tires. Ketones, carboxylic acids, epoxies, cyclohexane, and benzothiazole sulfenamide (BTS) intermediates were the most probable tire-related intermediates observed in the roadside soil samples. Thus, this simple, widely applicable, cost-effective sample preparation protocol for TRWP analysis can assist TRWP research advancement in terrestrial environments.

Microbial communities on plastic particles in surface waters differ from subsurface waters of the North Pacific Subtropical Gyre

The long-term fate of plastics in the ocean and their interactions with marine microorganisms remain poorly understood. In particular, the role of sinking plastic particles as a transport vector for surface microbes towards the deep sea has not been investigated. Here, we present the first data on the composition of microbial communities on floating and suspended plastic particles recovered from the surface to the bathypelagic water column (0-2000 m water depth) of the North Pacific Subtropical Gyre. Microbial community composition of suspended plastic particles differed from that of plastic particles afloat at the sea surface. However, in both compartments, a diversity of hydrocarbon-degrading bacteria was identified. These findings indicate that microbial community members initially present on floating plastics are quickly replaced by microorganisms acquired from deeper water layers, thus suggesting a limited efficiency of sinking plastic particles to vertically transport microorganisms in the North Pacific Subtropical Gyre.

Pelagic distribution of plastic debris (> 500 µm) and marine organisms in the upper layer of the North Atlantic Ocean

At present, the distribution of plastic debris in the ocean water column remains largely unknown. Such information, however, is required to assess the exposure of marine organisms to plastic pollution as well as to calculate the ocean plastic mass balance. Here, we provide water column profiles (0–300 m water depth) of plastic (0.05–5 cm in size) concentration and key planktonic species from the eastern North Atlantic Ocean. The amount of plastic decreases rapidly in the upper few meters, from ~ 1 item/m³ (~ 1000 µg/m³) at the sea surface to values of ~ 0.001–0.01 items/m³ (~ 0.1–10 µg/m³) at 300 m depth. Ratios of plastic to plankton varied between ~ 10^–5 and 1 plastic particles per individual with highest ratios typically found in the surface waters. We further observed that pelagic ratios were generally higher in the water column below the subtropical gyre compared to those in more coastal ecosystems. Lastly, we show plastic to (non-gelatinous) plankton ratios could be as high as ~ 10²–10⁷ plastic particles per individual when considering reported concentrations of small microplastics < 100 μm. Plastic pollution in our oceans may therefore soon exceed estimated safe concentrations for many pelagic species.

From freshwaters to bivalves: Microplastic distribution along the Saint-Lawrence river-to-sea continuum

Despite the close connection of freshwaters to human health, the occurrence and fate of microplastics in marine estuaries remain poorly documented. To study these particles in the Saint-Lawrence River (Quebec, Canada), surface water and marine bivalve samples were collected along the river-to-sea continuum. The water samples were subdivided to characterize the large microplastics (LMPs; 300-3200 µm) and the small microplastics (SMPs; 20-300 µm). Particles were identified by microscopy and infrared spectroscopy techniques. The concentration of LMPs was higher in the surface water in the downstream stations (0.0319 ± 0.0147 items.L^-1) compared to the upstream stations (0.0007 ± 0.0006 items.L^-1). No clear trend was observed for the SMPs. After digestion of the biological tissues, the microplastics ingested by the bivalves were recovered and characterized by microscopy coupled with infrared spectroscopy. Up to 3 items were found per bivalve suggesting that these particles are also present in the water column of the marine estuary and the gulf. The physico-chemical gradients along the continuum were monitored since they could be directly involved in the vertical and horizontal transport of microplastics. This study provides scarce field data collected along the world's largest estuary and gives new insights concerning the fate of microplastics along a river-to-sea continuum.

Microplastics in decapod crustaceans: Accumulation, toxicity and impacts, a review

The presence of microplastics in the aquatic environment poses a serious threat not only to aquatic organisms but also to human beings that consume them. The uptake and effects of microplastics have been studied in almost all groups of aquatic organisms. This review details the different aspects of microplastics exposure in an ecologically and economically important group of crustaceans, the Decapods. A majority of Decapod crustaceans such as prawns, shrimp, crabs, lobsters and crayfish are consumed as seafood and play important roles in food chains and food webs. Numerous studies are available on the accumulation of microplastics in tissues such as the gills, hepatopancreas and gastrointestinal tract in these organisms. Experimental studies have also highlighted the toxic effects of microplastics such as oxidative stress, immunotoxicity and reproductive and developmental toxicity in them. This review also summarizes the ecological impacts and implications in human beings as well as lacunae with regard to microplastic uptake in Decapods.

Microplastics in intertidal water of South Australia and the mussel Mytilus spp.; the contrasting effect of population on concentration

Microplastics, plastic particles <5 mm in size, are of global concern as human-caused pollutants in marine and fresh waters, and yet little is known of their distribution, behaviour and ecological impact in the intertidal environment of South Australia. This study confirms for the first time, the presence of microplastic in the South Australian intertidal ecosystem by quantifying the abundance of particles in intertidal water and in the keystone species, the blue mussel, Mytilus spp., an important fisheries species, at ten and six locations respectively, along the South Australian coastline. For a remote region known for its pristine environment, microplastic concentration in intertidal water was found to be low to moderate (mean = 8.21 particles l^-1 ± 4.91) relative to global levels and microplastic abundance in mussels (mean = 3.58 ± 8.18 particles individual^-1) was within the range also reported globally. Microplastic particles were ubiquitous across sites and bioavailable by size in water (mean = 906.36 μm) and in mussel (mean = 983.29 μm) raising concerns for the health of South Australia's unique coastal ecosystems and for the human food chain. Furthermore, a positive correlation was found between human coastal population size and microplastic concentration in intertidal water, irrespective of influences from industry - tourism, fishing and shipping ports. FTIR analysis determined plastic type to include polyamide (PA), polyethylene (PE), polypropylene (PP), acrylic resin, polyethyleneterephthalate (PET) and cellulose, suggesting synthetic and semi-synthetic particles from single-use, short-life cycle products, fabrics, ropes and cordage. Our findings shed light on the urgent need to establish the local sources of microplastic pollution in order to assist the community, industry and government to reduce the impact of microplastic on the fragile marine systems within South Australian intertidal waters and on the organisms associated with the human food chain.

First long-term evidence of microplastic pollution in the deep subtropical Northeast Atlantic

No anthropogenic pollutant is more widespread in the aquatic and terrestrial environment than microplastic; however, there are large knowledge gaps regarding its origin, fate, or temporal variations in the oceans. In this study, we analyzed sediment trap material from the deep subtropical Northeast Atlantic (2000 m) in a long-term record (2003-2015) to assess the role of the deep ocean as a potential sink of microplastics. Microplastic particles were identified in all 110 analyzed samples with flux rates of 1.13-3146.81 items d^-1 m^-2. Calculated microplastic mass fluxes ranged between 0.10 and 1977.96 μg d^-1 m^-2, representing up to 8% of the particle flux. Between years, the composition of the different polymers changed significantly, dominated by polyethylene, whose amount was correlated with the lithogenic input. The correlation between polyethylene and the lithogenic fraction was attributed to an air transport pathway from northeast Africa and surrounding regions. The second most abundant polymer detected in our study was polyvinyl chloride, which is not correlated with lithogenic or biogenic particle flux fractions. Instead, we observed seasonality for polyvinyl chloride with recurring high fluxes in winter before the plankton bloom and significantly lower amounts in summer. Other polymers identified were polypropylene, polyethylene terephthalate, and lower numbers of polystyrene and polymethyl methacrylate. The average microplastic particle size for all samples and polymers was 88.44 ± 113.46 μm, with polyethylene and polyvinyl chloride having the highest proportion of small particles (<100 μm). Our findings provide first insights into temporal variations of sinking microplastics, which are crucial for understanding the fate of plastic in the oceans.

Impact of waste of COVID-19 protective equipment on the environment, animals and human health: a review

During the Corona Virus Disease 2019 (COVID-19) pandemic, protective equipment, such as masks, gloves and shields, has become mandatory to prevent person-to-person transmission of coronavirus. However, the excessive use and abandoned protective equipment is aggravating the world's growing plastic problem. Moreover, above protective equipment can eventually break down into microplastics and enter the environment. Here we review the threat of protective equipment associated plastic and microplastic wastes to environments, animals and human health, and reveal the protective equipment associated microplastic cycle. The major points are the following:1) COVID-19 protective equipment is the emerging source of plastic and microplastic wastes in the environment. 2) protective equipment associated plastic and microplastic wastes are polluting aquatic, terrestrial, and atmospheric environments. 3) Discarded protective equipment can harm animals by entrapment, entanglement and ingestion, and derived microplastics can also cause adverse implications on animals and human health. 4) We also provide several recommendations and future research priority for the sustainable environment. Therefore, much importance should be attached to potential protective equipment associated plastic and microplastic pollution to protect the environment, animals and humans.

Unprecedented marine microplastic contamination from the X-Press Pearl container vessel disaster

The objectives of the research was to assess the coastal pollution by plastic nurdles, pyrolitic debris, associated potential toxic elements (PTEs) concentrations and mitigatory efforts by the worst ever maritime accident of a chemical and plastic boarded container vessel; MV X-Press Pearl. Field sampling was carried out three times during May, June, and September 2021 at Sarakkuwa, Sri Lanka. Pellet pollution index (PPI) was determined to compare the degree of plastics pollution. Density separation (NaCl) followed by wet peroxide digestion for plastic separation and characterized by Fourier transform infrared spectroscopic, thermo gravimetric analysis and differential scanning calorimetric analysis. Sand and plastics samples were digested and analyzed for PTEs (Li, Mo, Cr, Pb, and Cu), are suspect to mix during disaster. Identified debris were mostly confirmed as low-density polyethylene, epoxy resins, olefin copolymers, aromatic polyamides, natural rubber, and polyethylene terephthalate. Sulfur contamination and physical erosion were observed in nurdles received in June and September. Calculated PPIs were 'high' for Sarakkuwa beach even in September with a very high pellet pollution degree (10.24 pellets per m²) compared to the control obtained from the same site in 2020 (1.6 pellets per m²). Input sand for the blue treatment facility was found as the extremely contaminated with Mo and Li with 239.71 and 1.69 mg/kg respectively other than microplastics. Blue treatment facility seemed effective in physical separation of microplastics from sand, however, it is an exhausting process due to continuous receive of microplastics from the waves and excavation of sea shore.

Toxicity evaluation of polypropylene microplastic on marine microcrustacean Artemia salina: An analysis of implications and vulnerability

Polypropylene microplastic particles are one of the predominant pollutants in marine ecosystems and their toxic effects are unknown in aquatic biota. The study aims to prepare the spherical shaped polypropylene microplastics (size range 11.86 μm-44.62 μm) and assess their toxic effects (1, 25, 50, 75 and 100 μg/mL) in various life stages (nauplii, metanauplii and juvenile) of marine microcrustacean Artemia salina within 48 h. In addition, microplastics ingestion by Artemia nauplii was proved by FTIR analysis. The results revealed, microplastics accumulation in their tract leads to change in their homeostasis, as followed increase in the oxidative burst causes mortality in nauplii (LC₅₀ 40.947 μg/mL) and meta nauplii (LC₅₀ 51.954 μg/mL). In juvenile, swimming behaviour was changed. Moreover, microplastic consumption disturbs the antioxidant biomarkers such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione -S- Transferase (GST) and reduces the neurotransmitter enzyme acetylcholinesterase (AChE) activity. In addition, histology of juvenile Artemia showed damage in epithelial cells. This study indicates that exposure to polypropylene microplastics is more harmful to zooplanktonic organisms of the marine ecosystem.

Vertical distribution and river-sea transport of microplastics with tidal fluctuation in a subtropical estuary, China

The river-sea transport of microplastic with complex environmental conditions and diverse driving factors has received growing attention in the estuary. This research investigated the vertical distribution of microplastics in the water column and surface sediments and explored the effect of tidal variation on the transport of microplastics in Jiulong Estuary and Xiamen Bay, China. Results show that the microplastics in the estuary (630 ± 515 μm) was significantly larger than that in the bay (344 ± 420 μm, p < 0.01). Low-density microplastics are present in the whole water column, while high-density microplastics was apt to accumulate in the bottom water and surface sediment suggesting biofouling and material density of microplastics synergistic affect its vertical distribution. Every 1-2 h high-frequency samples collected in a whole tide found the increase of fine size (45-300 μm) and decrease of large size (>300 μm) in the flood tide, which implied fine microplastics were easily driven into the estuary from the bay at flood tide than large microplastics. The abundance of microplastics in the sediments decreased in the fast-rising and fast-falling period implies the tide influences the fragmentation and resuspension of microplastics in the estuary. Finally, the flux of microplastics entering Xiamen Bay was 53.5 t/month in the moderate flow month were estimated based on the abundance of different water layers instead of floating microplastics in the surface water.

Microplastics in the Deep: Comparing Dietary and Plastic Ingestion Data between Two Mediterranean Bathyal Opportunistic Feeder Species, Galeus melastomus, Rafinesque, 1810 and Coelorinchus caelorhincus (Risso, 1810), through Stomach Content Analysis

Marine plastic pollution is currently an issue of mounting concern around the world. Stomach content of marine fish has been increasingly used as a valid proxy for detecting the presence of such a pollutant in marine biota, both for coastal and deep-water environments. Although ingestion of microplastics has been reported in an increasing number of species, the patterns of ingestion still remain unclear, depending closely on the interaction between the species and types of microplastics involved. In this context, we analysed and compared the stomach contents of two bathyal dwelling opportunistic feeder species namely Galeus melastomus and Coelorinchus caelorhincus. In particular, we analysed microplastic items according to their dimension, morphology and colour, and diet’s variation with size obtained through prey identification. Both species showed a higher frequency of occurrence of the blue filament-like middle-sized microplastics (1.01–4.75 mm) compared with the other categories, although this pattern was much more marked in C. caelorhincus than in G. melastomus. The latter conversely showed a larger array of ingested plastic items in terms of shape and colour. Matching plastic ingestion with dietary data suggested potential predator confusion occurring in C. caelorhincus through active mis-selection of a defined type of microplastic instead of some particular family of polychaetes, which resemble in shape, size, and color to that type. Otherwise, G. melastomus appeared more prone to a random ingestion of a larger array of microplastic items because of a more generalistic and less selective feeding strategy. Although further validation is needed, stomach contents of the two species showed evidence strong enough to be considered as potential bioindicator species of microplastic pollution, as required by the Marine Strategy Framework Directive for monitoring this pollutant in the marine environment.

Detection of plastic particles in marine sponges by a combined infrared micro-spectroscopy and pyrolysis-gas chromatography-mass spectrometry approach

Plastic pollution threatens the marine environment, especially due to the adverse effects caused by micro and nano particles interacting with the marine biota. In order to provide reliable data regarding micro and nanoplastic contamination and the related impacts, efficient analytical solutions are needed. We developed a new analysis workflow that uses marine sponges to monitor plastic pollution by characterizing the plastic particles accumulated in their tissue. Specimens of cf. Haliclona (Haplosclerida) were sampled in the Maldivian archipelago. The aim was to optimize the method and to carry out a pilot study of the contamination of the related reef habitat. Particles were isolated, size fractioned, counted and submitted to morphological and chemical characterization. The constituting polymer was identified by infrared microspectroscopy for particles >25 μm, and by pyrolysis coupled with gas chromatography mass spectrometry for those <25 μm. Method recoveries were between 87 and 83% and limits of quantitation (LOQs) were between 6.6 and 30.2 ng/g. Analyses showed that 70% of the sponges presented plastic contamination, with an average of 1.2 particles/g tissue for the 25-150 μm size range, and a total plastic concentration of up to 4.8 μg/g in the 0.2-25 μm size range, with polyolefin being the most represented polymer in both size ranges. Overall, the study demonstrated the reliability of the proposed analytical workflow and of the use of sponges as biosamplers for plastic particles.

Large quantities of small microplastics permeate the surface ocean to abyssal depths in the South Atlantic Gyre

Hundreds of studies have surveyed plastic debris in surface ocean gyre and convergence zones, however, comprehensive microplastics (MPs, ≤5 mm) assessments beneath these surface accumulation areas are lacking. Using in situ high-volume filtration, Manta net and MultiNet sampling, combined with micro-Fourier-transform-infrared imaging, we discovered a high abundance (up to 244.3 pieces per cubic meter [n m^-3 ]) of small microplastics (SMPs, characteristically <100 μm) from the surface to near-sea floor waters of the remote South Atlantic Subtropical Gyre. Large horizontal and vertical variations in the abundances of SMP were observed, displaying inverse vertical trends in some cases. SMP abundances in pump samples were more than two orders of magnitude higher than large microplastics (LMPs, >300 μm) concurrently collected in MultiNet samples. Higher-density polymers (e.g., alkyd resins and polyamide) comprised >65% of the total pump sample count, highlighting a discrepancy between polymer compositions from previous ocean surface-based surveys, typically dominated by buoyant polymers such as polyethylene and polypropylene. Contrary to previous reports stating LMP preferentially accumulated at density gradients, SMP with presumably slower sinking rates are much less influenced by density gradients, thus resulting in a more even vertical distribution in the water column, and potentially longer residence times. Overall, our findings suggest that SMP is a critical and largely underexplored constituent of the oceanic plastic inventory. Additionally, our data support that weak current systems contribute to the formation of SMP hotspots at depth, implying a higher encounter rate for subsurface particle feeders. Our study unveils the prevalence of plastics in the entire water column, highlighting the urgency for more quantification of the deep-ocean MP, particularly the smaller size fraction, to better understand ecosystem exposure and to predict MP fate and impacts.

The role of mesopelagic fishes as microplastics vectors across the deep-sea layers from the Southwestern Tropical Atlantic

Microplastics (MPs; <5 mm) are a macro issue recognised worldwide as a threat to biodiversity and ecosystems. Widely distributed in marine ecosystems, MPs have already been found in the deep-sea environment. However, there is little information on ecological mechanisms driving MP uptake by deep-sea species. For the first time, this study generates data on MP contamination in mesopelagic fishes from the Southwestern Tropical Atlantic (SWTA) to help understand the deep-sea contamination patterns. An alkaline digestion protocol was applied to extract MPs from the digestive tract of four mesopelagic fish species: Argyropelecus sladeni, Sternoptyx diaphana (Sternoptychidae), Diaphus brachycephalus, and Hygophum taaningi (Myctophidae). A total of 213 particles were recovered from 170 specimens, and MPs were found in 67% of the specimens. Fibres were the most common shape found in all species, whereas polyamide, polyethylene, and polyethylene terephthalate were the most frequent polymers. The most contaminated species was A. sladeni (93%), and the least contaminated was S. diaphana (45%). Interestingly, individuals caught in the lower mesopelagic zone (500-1000 m depth) were less contaminated with MPs than those captured in the upper mesopelagic layer (200-500 m). Our results highlight significant contamination levels and reveal the influence of mesopelagic fishes on MPs transport in the deep waters of the SWTA.

Association of zoonotic protozoan parasites with microplastics in seawater and implications for human and wildlife health

Plastics are widely recognized as a pervasive marine pollutant. Microplastics have been garnering increasing attention due to reports documenting their ingestion by animals, including those intended for human consumption. Their accumulation in the marine food chain may also pose a threat to wildlife that consume species that can accumulate microplastic particles. Microplastic contamination in marine ecosystems has thus raised concerns for both human and wildlife health. Our study addresses an unexplored area of research targeting the interaction between plastic and pathogen pollution of coastal waters. We investigated the association of the zoonotic protozoan parasites Toxoplasma gondii, Cryptosporidium parvum, and Giardia enterica with polyethylene microbeads and polyester microfibers. These pathogens were chosen because they have been recognized by the World Health Organization as underestimated causes of illness from shellfish consumption, and due to their persistence in the marine environment. We show that pathogens are capable of associating with microplastics in contaminated seawater, with more parasites adhering to microfiber surfaces as compared with microbeads. Given the global presence of microplastics in fish and shellfish, this study demonstrates a novel pathway by which anthropogenic pollutants may be mediating pathogen transmission in the marine environment, with important ramifications for wildlife and human health.

Residual additives in marine microplastics and their risk assessment - A critical review

This review summarizes the current state of knowledge regarding the risk assessment of plastic-associated residual additives, i.e. residual monomers, degradation products and additives, in the marine environment, also considering effects of weathering and bioavailability. Experimental studies have found a number of organic and metal additive compounds in leachates from plastics, and the analysis of weathered plastic particles, such as polyethylene, polypropylene and polystyrene particles sampled on beaches and shorelines, has identified residual additives, such as flame retardants, plasticizers, UV stabilizers and antioxidants. While the transfer of e.g. PBDEs to organisms upon ingestion has been demonstrated, studies on uptake and bioaccumulation of plastic-associated chemicals are inconclusive. Studies on hazard and risk assessments are few, and focus on monomers and/or a limited number of high concentration additives, such as phthalates and flame retardants. The risk assessment results vary between low, moderate and high risks of specific additives, and are not necessarily consistent for the same compound. Given the large number of chemicals potentially introduced into the marine environment with plastic particles and the challenges associated with the correct quantification of exposure concentrations and toxicity thresholds, the question arises whether new risk assessment concepts may be needed.

Temporal Variability of Microparticles Under the Seattle Aquarium, Washington State: Documenting the Global Covid-19 Pandemic

Anthropogenic debris including microparticles (<5 mm) are ubiquitous in marine environments. The Salish Sea experiences seasonal fluctuations in precipitation, river discharge, sewage overflow events, and tourism-all variables previously thought to have an impact on microparticle transport and concentrations. Our goals are two-fold: 1) describe long-term microparticle contamination data including concentration, type, and size; and 2) determine if seasonal microparticle concentrations are dependent on environmental or tourism variables in Elliott Bay, Salish Sea. We sampled 100 L of seawater at a depth of approximately 9 m at the Seattle Aquarium, Seattle, Washington State, United States, approximately every two weeks from 2019 through 2020 and used an oil extraction protocol to separate microparticles. We found that microparticle concentrations ranged from 0 to 0.64 particles L^-1 and fibers were the most common type observed. Microparticle concentrations exhibited a breakpoint on 10 April 2020, where estimated slope and associated microparticle concentration significantly declined. Further, when considering both environmental as well as tourism variables, temporal microparticle concentration was best described by a mixed-effects model, with tourism as the fixed effect and the person counting microparticles as the random effect. Although monitoring efforts presented set out to identify effects of seasonality and interannual differences in microparticle concentrations, it instead captured an effect of decreased tourism due to the global Covid-19 pandemic. Long-term monitoring is critical to establish temporal microparticle concentrations and to help researchers understand if there are certain events, both seasonal and sporadic (e.g., rain events, tourism, or global pandemics), when the marine environment is more at risk from anthropogenic pollution. Environ Toxicol Chem 2022;41:917-930. © 2021 Seattle Aquarium. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Acute toxicity of bioplastic leachates to Paracentrotus lividus sea urchin larvae

In an attempt to ensure that bioplastics, progressively replacing petrochemical-derived plastics, do not release any harmful compound to the environment, the study assessed the toxic effects of three innovative bioplastic products: polyhydroxybutyrate resin (PHB), polylactic acid cups (PLA) and a polylactic acid/polyhydroxyalkanoate 3D printing filament (PLA/PHA), together with a synthetic polyvinyl chloride (PVC) toy in Paracentrotus lividus sea urchin larvae. PVC toy was the most toxic material, likely due to the added plasticizers; remarkably, even if PHB is conceived as a nontoxic polymer, it showed a slight toxicity and Gas Chromatography-Mass Spectometry analysis (GC-MS) revealed the presence of a wide range of additives. Conversely, PLA cups and PLA/PHA filament were innocuous for the larvae, a positive outcome for these renewable solutions. Proven that additives are also used in some bioplastic formulations, they should be carefully addressed to ensure that they are as safe as regarded.

Trans-polar drift-pathways of riverine European microplastic

High concentrations of microplastic particles are reported across the Arctic Ocean–yet no meaningful point sources, suspension timelines, or accumulation areas have been identified. Here we use Lagrangian particle advection simulations to model the transport of buoyant microplastic from northern European rivers to the high Arctic, and compare model results to the flux of sampled synthetic particles across the main entrance to the Arctic Ocean. We report widespread dispersal along the Eurasian continental shelf, across the North Pole, and back into the Nordic Seas; with accumulation zones over the Nansen basin, the Laptev Sea, and the ocean gyres of the Nordic Seas. The equal distribution of sampled synthetic particles across water masses covering a wide time frame of anthropogenic influence suggests a system in full saturation rather than pronounced injection from European sources, through a complex circulation scheme connecting the entire Arctic Mediterranean. This circulation of microplastic through Arctic ecosystems may have large consequences to natural ecosystem health, highlighting an ever-increasing need for better waste management.

The Occurrence of Microplastics in Sediment Cores from Two Mangrove Areas in Southern Thailand

Mangroves are areas that connect the land and sea, and are important to the ecosystem. They are important places for food sources and the habitat of aquatic fauna in the tidal areas. However, the existence of plastic debris poses a risk to the aquatic environment. This study aimed to investigate the accumulation of microplastics (MPs) in sediment cores from two mangrove areas. The first mangrove area is in the outer section of the Songkhla lagoon (SK), while the second is in the coastal area of Pattani province (PN). Sediment core sampling was performed from SK = 8 stations and PN = 5 stations. Surface enrichment of MP was observed, especially in sediments of 0–4 cm. MPs were found throughout the depth in both areas, while fewer MPs were found in deeper sediment core layers (p < 0.05) at some stations inside the mangrove zone. Simple linear regression of the observed MPs and distance in the horizontal were found to be significant at SK within the mangrove zone with r2 = 0.79 (p < 0.05). MP fibers were the most commonly found MP type in both areas and were less than 1 mm. Blue and black MPs were the most abundant colors found in both areas. The six polymer types reported in this study comprised polyethylene, rayon, rubber, styrene, Poly (vinyl acetate), and paint. The findings of the present study suggest that long-term monitoring of marine debris along coastlines is necessary to help improve national policies and measures related to marine plastic debris.