Microplastics in Latin America and the Caribbean: A review on current status and perspectives

Microplastics in water resources: Global pollution circle, possible technological solutions, legislations, and future horizon

Beneath the surface of our ecosystems, microplastics (MPs) silently loom as a significant threat. These minuscule pollutants, invisible to the naked eye, wreak havoc on living organisms and disrupt the delicate balance of our environment. As we delve into a trove of data and reports, a troubling narrative unfolds: MPs pose a grave risk to both health and food chains with their diverse compositions and chemical characteristics. Nevertheless, the peril extends further. MPs infiltrate the environment and intertwine with other pollutants. Worldwide, microplastic levels fluctuate dramatically, ranging from 0.001 to 140 particles.m-3 in water and 0.2 to 8766 particles.g-1 in sediment, painting a stark picture of pervasive pollution. Coastal and marine ecosystems bear the brunt, with each organism laden with thousands of microplastic particles. MPs possess a remarkable ability to absorb a plethora of contaminants, and their environmental behavior is influenced by factors such as molecular weight and pH. Reported adsorption capacities of MPs vary greatly, spanning from 0.001 to 12,700 μg·g-1. These distressing figures serve as a clarion call, demanding immediate action and heightened environmental consciousness. Legislation, innovation, and sustainable practices stand as indispensable defenses against this encroaching menace. Grasping the intricate interplay between microplastics and pollutants is paramount, guiding us toward effective mitigation strategies and preserving our health ecosystems.

A review of plastic debris in the South American Atlantic Ocean coast - Distribution, characteristics, policies and legal aspects

The presence of plastics in the oceans has already become a pervasive phenomenon. Marine pollution by plastics surpasses the status of an emerging threat to become a well-established environmental problem, boosting research on this topic. However, despite many studies on the main seas and oceans, it is necessary to compile information on the South American Atlantic Ocean Coast to identify the lack of research and expand knowledge on marine plastic pollution in this region. Accordingly, this paper conducted an in-depth review of monitoring methods, sampling, and identification of macroplastics and microplastics (MPs) in water, sediments, and biota, including information on legal requirements from different countries as well as non-governmental initiatives. Brazil was the country with the highest number of published papers, followed by Argentina. MPs accounted for 75 % of the papers selected, with blue microfibers being the most common morphology, whereas PE and PP were the most abundant polymers. Also, a lack of standardization in the methodologies used was identified; however, the sites with the highest concentrations of MPs were the Bahía Blanca Estuary (Argentina), Guanabara Bay (Brazil), and Todos os Santos Bay (Brazil), regardless of the method applied. Regarding legislation, Uruguay and Argentina have the most advanced policies in the region against marine plastic pollution due to their emphasis on the life cycle and the national ban on certain single-use plastics. Therefore, considering its content, this expert review can be useful to assist researchers dealing with plastic pollution along the South American Atlantic Ocean Coast.

Microplastics removal in wastewater treatment plants: A review of the different approaches to limit their release in the environment

In last 10 years, the interest about the presence of microplastics (MPs) in the environment has strongly grown. Wastewaters function as a carrier for MPs contamination from source to the aquatic environment, so the knowledge of the fate of this emerging contaminant in wastewater treatment plants (WWTPs) is a priority. This work aims to review the presence of MPs in the influent wastewater (WW) and the effectiveness of the treatments of conventional WWTPs. Moreover, the negative impacts of MPs on the management of the processes have been also discussed. The work also focuses on the possible approaches to tackle MPs contamination enhancing the effectiveness of the WWTPs. Based on literature results, despite WWTPs are not designed for MPs removal from WW, they can effectively remove the MPs (up to 99 % in some references). Nevertheless, they normally act as "hotspots" of MPs contamination considering the remaining concentration of MPs in WWTPs' effluents can be several orders of magnitude higher than receiving waters. Moreover, MPs removed from WW are concentrated in sewage sludge (potentially >65 % of MPs entering the WWTP) posing a concern in case of the potential reuse as a soil improver. This work aims to present a paradigm shift intending WWTPs as key barriers for environmental protection. Approaches for increasing effectiveness against MPs have been discussed in order to define the optimal point(s) of the WWTP in which these technologies should be located. The need of a future legislation about MPs in water and sludge is discussed.

Microplastics and plastisphere at surface waters in the Southwestern Caribbean sea

Pollution generated by plastic waste has brought an environmental problem characterized by the omnipresence of smaller pieces of this material known as microplastics (MP). This issue was addresses by collecting samples with 250 μm pore size nets in two marine-coastal sectors of Southwestern Caribbean Sea during two contrasting seasons. Higher concentrations were found in rainy season than in dry season, reaching respectively 1.72 MP/m3 and 0.22 MP/m3. Within each sector, there were differences caused firstly by localities of higher concentrations of semi-closed water bodies localities during rainy season (Ciénaga Grande de Santa Marta and La Caimanera marsh), and secondly by lower concentrations of localities with less influenced of flow rates during dry season (Salamanca and Isla Fuerte). Moreover, the lowest concentration in dry season corresponding to La Caimanera marsh reflects how the community environmental management might decrease MP pollution. In both sectors and seasons, the particles of 0.3 mm (0.3-1.4 mm) size class dominated over those of 1.4 mm (1.4-5.0 mm) (reaching each respectively 1.33 MP/m3 and 0.39 MP/m3), with a dominance of fibers, except in the rainy season in Magdalena, where they were films. Using the FTIR technique, polypropylene was identified as the most abundant polymer in both sectors. The composition of the assemblage of microorganisms attached to microplastics presented higher richness and differed from that of free-living planktonic microbes. The most abundant members of the plastisphere were proteobacteria whose major representation was the pathogenic genus Vibrio, while the cyanobacteria dominated in seawater samples.

Microplastics in the Amazon biome: State of the art and future priorities

Microplastics (MPs) have been identified as a major potential threat to the biota and human health. Despite the exponential increase in MP research worldwide, few studies have focused on the extensive Amazon biome. To assess research priorities, the present study reviewed and summarized the available scientific knowledge on MPs in the Amazon, in addition to analyzing population and waste-management data, to evaluate potential sources of MPs in the hydrographic system. Poor sanitation conditions are a main source of MPs for the vast hydrographic basin, and, consequently, for the adjacent ocean. Secondary MPs predominated, mostly fibers (96% of debris), composed of polyamide (32%). Mean MP concentrations ranged from 0.34 to 38.3 particles.individual-1 in biota, 5 to 476,000 particles.m-3 in water, and 492.5 to 1.30848 × 107 particles.m-3 in sediment, values in close comparison with those found in areas profoundly affected by anthropogenic pollution. MPs were widespread in a range of Amazonian environments and species, and negative effects are probably occurring at various ecological levels. However, limited research, methodological constraints, flaws and the lack of standardization, combined with the continental dimensions of the Amazon, hampers the collection of the fundamental knowledge needed to reliably evaluate the impacts and implement effective mitigation measures. There is an urgent need to expand scientific data available for the region, improving local research infrastructure, and training and deploying local researchers.

Understanding the sources of marine litter in remote islands: The Galapagos islands as a case study

Determining the sources of marine litter is necessary to mitigate this increasing global problem. Plastic bottles are useful tracers of marine litter and constitute the main item (24%) stranding on remote beaches in the Galapagos Islands. The aim of this study was to estimate the abundance of plastic bottles in remote beaches and inferred their sources. To do so, we collected plastic bottles at 60 remote Galapagos Island beaches from 2018 to 2022. 76% of beaches were qualified as badly polluted, with >34 bottles·100 m-1. Most identified bottles came from Peru (71%), followed by China (17%) and Ecuador (9%). Although most locally-sold products are made in Ecuador, they contribute little to beach litter loads. Polyethylene terephthalate bottles with lid (necessary for litter dispersal) represented 88% of all bottles, demonstrating that most of the litter reaching the Galapagos comes from distant sources, mainly from South America. However, bottle ages indicate that at least 10% of Peruvian, 26% of Ecuadorian, and all Chinese bottles likely were dumped from ships. Reducing marine litter reaching the Galapagos Islands requires tackling litter leakage from land-based sources in South America and better compliance with regulations banning the dumping of plastics and other persistent wastes from ships.

Micro(nano)plastics in marine medaka: Entry pathways and cardiotoxicity with triphenyltin

The simultaneous presence of micro(nano)plastics (MNPs) and pollutants represents a prevalent environmental challenge that necessitates understanding their combined impact on toxicity. This study examined the distribution of 5 μm (PS-MP5) and 50 nm (PS-NP50) polystyrene plastic particles during the early developmental stages of marine medaka (Oryzias melastigma) and assessed their combined toxicity with triphenyltin (TPT). Results showed that 2 mg/L PS-MP5 and PS-NP50 could adhere to the embryo surface. PS-NP50 can passively enter the larvae and accumulate predominantly in the intestine and head, while PS-MP5 cannot. Nonetheless, both types can be actively ingested by the larvae and distributed in the intestine. 2 mg/L PS-MNPs enhance the acute toxicity of TPT. Interestingly, high concentrations of PS-NP50 (20 mg/L) diminish the acute toxicity of TPT due to their sedimentation properties and interactions with TPT. 200 μg/L PS-MNPs and 200 ng/L TPT affect complement and coagulation cascade pathways and cardiac development of medaka larvae. PS-MNPs exacerbate TPT-induced cardiotoxicity, with PS-NP50 exhibiting stronger effects than PS-MP5, which may be related to the higher adsorption capacity of NPs to TPT and their ability to enter the embryos before hatching. This study elucidates the distribution of MNPs during the early developmental stages of marine medaka and their effects on TPT toxicity, offering a theoretical foundation for the ecological risk assessment of MNPs.

Microplastics in Ecuador: A review of environmental and health-risk assessment challenges

Pollution from plastic debris and microplastics (MPs) is a worldwide issue. Classified as emerging contaminants, MPs have become widespread and have been found not only in terrestrial and aquatic ecosystems but also within the food chain, which affects both the environment and human health. Since the outbreak of COVID-19, the consumption of single-use plastics has drastically increased, intensifying mismanaged plastic waste in countries such as Ecuador. Therefore, the aim of this review is to 1) summarize the state of MP-related knowledge, focusing on studies conducted with environmental matrices, biota, and food, and 2) analyze the efforts by different national authorities and entities in Ecuador to control MP contamination. Results showed a limited number of studies have been done in Ecuador, which have mainly focused on the surface water of coastal areas, followed by studies on sediment and food. MPs were identified in all samples, indicating the lack of wastewater management policies, deficient management of solid wastes, and the contribution of anthropogenic activities such as artisanal fishing and aquaculture to water ecosystem pollution, which affects food webs. Moreover, studies have shown that food contamination can occur through atmospheric deposition of MPs; however, ingredients and inputs from food production, processing, and packaging, as well as food containers, contribute to MP occurrence in food. Further research is needed to develop more sensitive, precise, and reliable detection methods and assess MPs' impact on terrestrial and aquatic ecosystems, biota, and human health. In Ecuador specifically, implementing wastewater treatment plants in major cities, continuously monitoring MP coastal contamination, and establishing environmental and food safety regulations are crucial. Additionally, national authorities need to develop programs to raise public awareness of plastic use and its environmental effects, as well as MP exposure's effects on human health.

A systematic review on the current situation of emerging pollutants in Mexico: A perspective on policies, regulation, detection, and elimination in water and wastewater

Emerging pollutants (EPs) emerged as a group of new compounds whose presence in the environment has been widely detected in Mexico. In this country, different concentrations of pharmaceutical compounds, pesticides, dyes, and microplastics have been reported, which vary depending on the region and the analyzed matrix (i.e., wastewater, surface water, groundwater). The evidence of the EPs' presence focuses on the detection of them, but there is a gap in information regarding is biomonitoring and their effects in health in Mexico. The presence of these pollutants in the country associated with lack of proper regulations in the discharge and disposal of EPs. Therefore, this review aims to provide a comprehensive view of the current environmental status, policies, and frameworks regarding Mexico's situation. The review also highlights the lack of information about biomonitoring since EPs are present in water even after their treatment, leading to a critical situation, which is high exposure to humans and animals. Although, technologies to efficiently eliminate EPs are available, their application has been reported only at a laboratory scale thus far. Here, an overview of health and environmental impacts and a summary of the research works reported in Mexico from 2014 to 2023 were presented. This review concludes with a concrete point of view and perspective on the status of the EPs' research in Mexico as an alert for government entities about the necessity of measures to control the EPs disposal and treatment.

Microplastics as contaminants in the Brazilian environment: an updated review

Microplastics have long been present in marine and terrestrial environments and have emerged in recent decades as a global environmental concern. This pollutant has been detected with increasing frequency in Brazilian territory and herein primarily highlights current information and developments about the quantity, distribution, techniques of identification, origins, and sources of microplastics and related pollutants in the Brazilian environment. We evaluated 79 publications from 2018 to December 2022, and some aspects can be highlighted: 27% of studies were published in the Journal Marine Pollution Bulletin; 22% of all studies were conducted in São Paulo city; and 52% of all microplastics found were collected from biota followed by sediment samples. According to the findings given here, microplastics in Brazilian habitats, which can reach concentrations of 4367 to 25,794 items m-2 in sediments, are becoming a serious problem in the Anthropocene age, and some topics regarding the open questions in this area were pointed out in this review.

First record of microplastic in the Brazilian sea hare Aplysia brasiliana Rang, 1828 (Mollusca: Aplysiidae)

The presence of plastic debris in the marine environment has reached massive levels in the past decades. In marine environments, microplastics can exist for hundreds of years and the presence of microplastics in this environment has been reported since 1970 and since then has been considered ubiquitous. Mollusks are being used as microplastic pollution indicators, especially in coastal areas and bivalves are more often used in microplastic-monitoring studies. On the other hand, gastropods are poorly used as indicators for microplastic pollution, even though they are the most diverse group of mollusks. The sea hares of the genus Aplysia are herbivorous gastropods, important model organisms commonly used in neuroscience studies, isolating the compounds in their defensive ink. Until today, there is no previous record of the presence of MPs in Aplysia gastropods. Therefore, this study aims to investigate the presence of microplastics in tissues of A. brasiliana found in southeastern Brazil. We collected seven individuals of A. brasiliana from a beach in southeastern Brazil, dissected them to isolate the digestive tract and the gills, and digested the tissues with a solution of 10 % NaOH. In the end, 1021 microplastic particles were found, 940 in the digestive tissue, and 81 in the gills. These results represent the first record of the presence of microplastics in the Brazilian sea hare A. brasiliana.

Microplastics in the environment: An urgent need for coordinated waste management policies and strategies

Microplastics (MPs) have become a prevalent environmental concern, exerting detrimental effects on marine and terrestrial ecosystems, as well as human health. Addressing this urgent issue necessitates the implementation of coordinated waste management policies and strategies. In this study, we present a comprehensive review focusing on key results and the underlying mechanisms associated with microplastics. We examine their sources and pathways, elucidate their ecological and human health impacts, and evaluate the current state of waste management policies. By drawing upon recent research and pertinent case studies, we propose a range of practical solutions, encompassing enhanced recycling and waste reduction measures, product redesign, and innovative technological interventions. Moreover, we emphasize the imperative for collaboration and cooperation across sectors and jurisdictions to effectively tackle this pressing environmental challenge. The findings of this study contribute to the broader understanding of microplastics and provide valuable insights for policymakers, researchers, and stakeholders alike.

Control strategies for microplastic pollution in groundwater

Groundwater is the primary source of water that occurs below the earth's surface. However, the advancement in technology and the increasing population, which lead to the discharge of contaminants such as microplastics (MPs), have an adverse impact on the quality of groundwater. MPs are ubiquitous pollutants that are widely found throughout the world. The maximum abundance of MPs is 4 items/L and 15.2 items/L in groundwater at the specific location of China and USA. Various factors can affect the migration of MPs from soil to groundwater. The occurrence of MPs in water causes serious health issues. Therefore, taking appropriate strategies to control MP contamination in groundwater is urgent and important. This review summarizes the current literature on the migration process of MPs from soil to groundwater along with possible methods for the remediation of MP-polluted groundwater. The main objective of the review is to summarize the technical parameters, process, mechanism, and characteristics of various remediation methods and to analyze strategies for controlling MP pollution in groundwater, providing a reference for future research. Possible control strategies for MP pollution in groundwater include two aspects: i) prevention of MPs from entering groundwater; ii) remediation of polluted groundwater with MPs (ectopic remediation and in-situ remediation). Formulating legislative measures, strengthening public awareness and producing more environment-friendly alternatives can be helpful to reduce the production of MPs from the source. Manage plastic waste reasonably is also a good strategy and the most important part of the management is recycling. The shortcomings of the current study and the direction of future research are also highlighted in the review.

Identifying opportunities for harmonized microplastics and mesoplastics monitoring for Caribbean Small Island Developing States using a spatiotemporal assessment of beaches in South Eleuthera, The Bahamas

Increasing quantities of microplastics and mesoplastics in the marine environment underscore the need for marine microplastics to be included in the global Plastics Treaty to end plastic pollution. Caribbean Small Island Developing States (SIDS) lack harmonized microplastics monitoring protocols, leaving them data deficient at the science-policy interface required for treaty negotiations. This baseline study assessed spatial and seasonal abundance and distribution of microplastic (1-5 mm) and mesoplastic (5-25 mm) on 16 beaches with three coastal exposures (Atlantic Ocean, Exuma Sound, Bahama Bank) in South Eleuthera, The Bahamas and its implications for Caribbean SIDS. Microplastics were the dominant debris type sampled (74 %) across all beaches, with significant spatial (p = 0.0005) and seasonal (p = 0.0363) differences in abundance and distribution across study sites. This baseline study identifies opportunities required for developing harmonized microplastics and mesoplastics monitoring by Caribbean SIDS to collect data to help support global plastics treaty negotiations.

Astaxanthin mitigates oxidative stress caused by microplastics at the expense of reduced skin pigmentation in discus fish

Microplastics (MPs) exposure generally triggers oxidative stress in fish species and vertebrate pigmentation is commonly influenced by oxidative stress, but MPs-induced oxidative stress on fish pigmentation and body color phenotype has not been reported. The aim of this study is to determine whether astaxanthin could mitigate the oxidative stress caused by MPs but at the expense of reduced skin pigmentation in fish. Here, we induced oxidative stress in discus fish (red skin color) by 40 or 400 items/L MPs under both astaxanthin (ASX) deprivation and supplementation. We found that lightness (L*) and redness (a*) values of fish skin were significantly inhibited by MPs under ASX deprivation. Moreover, MPs exposure significantly reduced ASX deposition in fish skin. The total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in fish liver and skin were both significantly increased with the increase of MPs concentration, but content of glutathione (GSH) in fish skin showed a significant decrease. For ASX supplementation, the L*, a* values and ASX deposition were significantly improved by ASX, including the skin of MPs-exposed fish. The T-AOC and SOD levels changed non-significantly in fish liver and skin under the interaction of MPs and ASX, but ASX significantly reduced GSH content in fish liver. Biomarker response index indicated that ASX could improve the moderately altered antioxidant defense status of MPs-exposed fish. This study suggests that the oxidative stress caused by MPs was mitigated by ASX but at expense of reduced fish skin pigmentation.

Micro- and mesoplastic pollution along the coast of Peru

Peru suffers from poor solid waste and coastal management, as well as evidenced plastic pollution in various forms. However, studies in Peru focusing on small plastic debris (i.e., meso- and microplastics) are still limited and inconclusive. Thus, the present study investigated the abundance, characteristics, seasonality, and distribution of small plastic debris along the coast of Peru. The abundance of small plastic debris is predominantly driven by specific locations, where a source of contamination is present, rather than presenting seasonal patterns. Meso- and microplastics were strongly correlated in both seasons (summer and winter), suggesting meso-plastic constantly breaking down as microplastic sources. Additionally, heavy metals (e.g., Cu, Pb) were found in low concentrations (mean concentrations < 0.4%) on the surface of some mesoplastics. Here, we provided a baseline on the multiple factors involving small plastic debris on the Peruvian coast and preliminarily identify associated contaminants.

Occurrence and risks of microplastics in the ecosystems of the Middle East and North Africa (MENA)

The ubiquitous nature of microplastics (MPs) in nature and the risks they pose on the environment and human health have led to an increased research interest in the topic. Despite being an area of high plastic production and consumption, studies on MPs in the Middle East and North Africa (MENA) region have been limited. However, the region witnessed a research surge in 2021 attributed to the COVID-19 pandemic. In this review, a total of 97 studies were analyzed based on their environmental compartments (marine, freshwater, air, and terrestrial) and matrices (sediments, water columns, biota, soil, etc.). Then, the MP concentrations and polymer types were utilized to conduct a risk assessment to provide a critical analysis of the data. The highest MP concentrations recorded in the marine water column and sediments were in the Mediterranean Sea in Tunisia with 400 items/m³ and 7960 items/kg of sediments, respectively. The number of MPs in biota ranged between 0 and 7525 per individual across all the aquatic compartments. For the air compartment, a school classroom had 56,000 items/g of dust in Iran due to the confined space. Very high risks in the sediment samples (Erⁱ > 1500) were recorded in the Caspian Sea and Arab/Persian Gulf due to their closed or semi-closed nature that promotes sedimentation. The risk factors obtained are sensitive to the reference concentration which calls for the development of more reliable risk assessment approaches. Finally, more studies are needed in understudied MENA environmental compartments such as groundwater, deserts, and estuaries.

Microplastic pollution in sediments of tropical shallow lakes

Forty-eight tropical shallow lakes (depth ≤ 4 m) across a climatic gradient were assessed for microplastic (MPs; <5 mm) pollution based on MPs concentrations in archive samples from lake shore sediments. The MPs were classified by type (fragments or fibres), colour (yellow, black, red, green, blue, white, and transparent), size (0.55 to 4.93 mm), and polymer (polyester, polyethylene, chlorinated polyethylene, and polyamide). Sediments were predominantly medium sand, and all samples (144) contained MPs, consisting of 24 % fragments (6.3 ± 11.3 MPs·300 g^-1) and 76 % fibres (21.25 ± 12.7 MPs·300 g^-1). The lake climate (humid, transitional, or semi-arid), type of surrounding land use (urban, semi-arid, or rural), and distance from the shoreline (0, 5 or 10 m) did not explain the differences in MPs concentrations, partially refuting the initial hypothesis. The only significant difference was between the sample medians for the number of fragments based on the region (H = 7.586; p = 0.0481). The number of fragments in the lakes in the humid region was greater than that in the semi-arid region (p < 0.05). Poor sanitation, sewage effluents, and solid wastes reaching and accumulating in the lakes may be the primary and transversal conditioning factors for this small difference among diverse environments. Freshwater lakes are investigated in all continents, and the present study contributes to the first record of MPs in shallow lake sediments in eastern South America. The 48 shallow lakes assessed showed a relatively low concentration of MPs compared to other lake contaminants reported in the international literature. This information coincides with public policies issued, regarding the control and reduction of plastics and MPs in Brazil, and the study region.

A systematic review on microplastic pollution in water, sediments, and organisms from 50 coastal lagoons across the globe

Coastal lagoons are transitional environments between continental and marine aquatic systems. Globally, coastal lagoons are of great ecological and socioeconomic importance as providers of valuable ecosystem services. However, these fragile environments are subject to several human pressures, including pollution by microplastics (MPs). The aim of this review was to identify and summarize advances in MP pollution research in coastal lagoons across the world. We consider peer-reviewed publications on this topic published in English and Spanish between 2000 and April 21, 2022, available in Scopus and Google Scholar. We found 57 publications with data on MP abundances and their characteristics in 50 coastal lagoons from around the world, 58% of which have some environmental protection status. The number of publications on this type of pollution in lagoons has increased significantly since 2019. Methodological differences amongst studies of MPs in coastal lagoons were nevertheless a limiting factor for wide-ranging comparisons. Most studies (77%) were conducted in single environmental compartments, and integration was limited, hampering current understanding of MP dynamics in such lagoons. MPs were more abundant in lagoons with highly populated shores and watersheds, which support intensive human activities. On the contrary, lagoons in natural protected areas had lower abundances of MPs, mostly in sediments and organisms. Fiber/filament and fragment shapes, and polyethylene, polyester, and polypropylene polymers were predominant. MPs had accumulated in certain areas of coastal lagoons, or had been exported to the sea, depending on the influence of seasonal weather, hydrodynamics, anthropogenic pressures, and typology of MPs. It is advised that future research on MP pollution in coastal lagoons should focus on methodological aspects, assessment/monitoring of pollution itself, MP dynamics and impacts, and prevention measures as part of a sound environmental management.

Overviewing the Ground Reality of Microplastic Effects on Seafoods, Including Fish, Shrimps and Crabs: Future Research Directions

While plastics are already notorious for their accumulation in the environment, which poses environmental challenges, invisible microplastics (MPS) are an even greater challenge. This review focuses on consolidating the reports available on MP accumulation in edible marine and freshwater fishes, shrimps, and crabs. The reality as to whether MPs in these edible aquatic organisms are really a cause of high concern is questioned and discussed. While the entrails of aquatic organisms are reported to contain high levels of MPs, because these products are consumed after the removal of the entrails and gut area in the majority of cases, the MP threat is questionable. The existence of MPs in these aquatic sources is validated but their potency in harming humans, aquatic organisms, and other interlinked species is unassessed. To overcome the difficulty in tracing the movement of MPs in a bigger ecosystem, this review proposes laboratory-based pilot studies mimicking real-world conditions, which will help us to understand the kinetics of MPs in the food chain. The effects of MPs on human welfare and health are yet to be assessed, and this is another gap that needs attention.

Microplastics in ASEAN region countries: A review on current status and perspectives

A literature assessment was conducted to determine the current state of microplastics research in ASEAN countries focusing on 1) microplastics in water, sediment, and water organisms; 2) microplastics' sources and dispersion; and 3) microplastics' environmental consequences, including human toxicity. ASEAN countries contributed only about 5 % of the global scholarly papers on microplastics, with Indonesia contributing the most followed by Malaysia and Thailand. The lack of standard harmonized sampling and processing methodologies made comparisons between research difficult. ASEAN contributes the most to plastic trash ending up in the ocean, indicating a need for more work in this region to prevent plastic pollution. Microplastics are found in every environmental compartment; however, their distribution and environmental consequences have not been sufficiently investigated. There are very few studies on microplastics in the human blood system as well as respiratory organs like the lungs, indicating that more research is needed.

Whole transcriptome sequencing analysis revealed key RNA profiles and toxicity in mice after chronic exposure to microplastics

Investigating the long-term effects of microplastics (MPs) in vivo is necessary for evaluating its biological toxicity. Previously, we showed that MPs elicit vascular dysfunctions in atherosclerotic mice. However, the effects of long-term treatment with environmental levels of MPs on biological functions and RNA expression profiles in wild-type mice are unknown. Here, C57BL/6 mice were administered 1000 μg/L MPs through their drinking water for 180 days. Transcriptomic analyses, biochemical analysis, and histopathological examination were conducted to determine the key signals and molecular mechanisms triggered by MPs in vivo using whole transcriptome sequencing, enzyme-linked immunosorbent assay, and histopathological analysis. Notably, our data revealed that MPs aggravated vascular lesions and organ injuries, particularly liver, kidney, and heart injuries. Additionally, MPs exacerbated oxidative injuries by inhibiting the activities of antioxidant enzymes and increasing the levels of the serum biochemistry indicator of organ damage. RNA sequencing of vascular tissues showed that 674 mRNAs, 39 lncRNAs, 196 miRNAs, and 565 circRNAs were abnormally expressed in MPs-treated mice compared with the untreated group. Pathway enrichment analyses identified pathways linked to the toxicity of MPs, including lysosomal, NOD-like receptor, and peroxisome proliferator-activated receptor pathways. Additionally, competing endogenous RNA networks were constructed and hub RNAs were identified using bioinformatics analysis. Taken together, our data suggested that toxicity induced by long-term exposure to MPs continually presents with extensive changes in biological features and global gene expression profiles. Our data provides new insights into the biological toxicity of MPs.

Interactions of microplastics with organic, inorganic and bio-pollutants and the ecotoxicological effects on terrestrial and aquatic organisms

As emerging contaminants, microplastics (MPs) have attracted global attention. They are a potential risk to organisms, ecosystems and human health. MPs are characterized by small particle sizes, weak photodegradability, and are good environmental carriers. They can physically adsorb or chemically react with organic, inorganic and bio-pollutants to generate complex binary pollutants or change the environmental behaviors of these pollutants. We systematically reviewed the following aspects of MPs: (i) Adsorption of heavy metals and organic pollutants by MPs and the key environmental factors affecting adsorption behaviors; (ii) Enrichment and release of antibiotic resistance genes (ARGs) on MPs and the effects of MPs on ARG migration in the environment; (iii) Formation of "plastisphere" and interactions between MPs and microorganisms; (iv) Ecotoxicological effects of MPs and their co-exposures with other pollutants. Finally, scientific knowledge gaps and future research areas on MPs are summarized, including standardization of study methodologies, ecological effects and human health risks of MPs and their combination with other pollutants.