Microplastics in three typical benthic species from the Arctic: Occurrence, characteristics, sources, and environmental implications

Effect of alternative natural diet on microplastic ingestion, functional responses and trophic transfer in a tri-trophic coastal pelagic food web

The patchy distribution of microplastics (MP) and their size range similar to planktonic organisms, are likely to have major ecological consequences, through MP ingestion, food dilution, and transfer across trophic levels. Our study applied a community module using tritrophic food chain with zooplankton as prey, and a planktivorous seabass fry as predator. We conducted a series of feeding experiments and recorded the direct uptake of MP under six different concentrations ranging from 25 to 800 particles L-1. We also estimated the indirect transfer of MP via trophic link. The ingestion rates for Brachionus plicatilis, Mesocyclops isabellae, and Lates calcarifer, were 3.7 ± 0.3 MP ind-1 min-1, 1.69 ± 0.1 MP ind-1 min-1, and 3.51 ± 0.52 MP ind-1 h-1, respectively. In the presence of a natural diet, rotifers and copepods ingested significantly lower number, whereas, fish fry ingested a higher number of MP, suggesting further vulnerability to the consumers of MP-contaminated fish and potential biomagnification at higher trophic levels. Overall, the MP uptake rate increased with increasing concentration, and finally leveled off, indicating a type II functional response to MP concentration. The presence of natural diet led to a lower Km value. In the indirect transfer experiment, 74 % of B. plicatilis and 78 % of M. isabellae individuals were contaminated with MP, when offered as prey. Brachionid mastax and MP particles were observed in the gut of copepods. The fish fry gut content also recorded brachionid mastax, MP-contaminated copepods, and MP particles, showing direct evidence of trophic transfer pointing to a cascading effect on higher trophic levels including humans via piscivory.

Understanding and addressing microplastic pollution: Impacts, mitigation, and future perspectives

Improper disposal of household and industrial waste into water bodies has transformed them into de facto dumping grounds. Plastic debris, weathered on beaches degrades into micro-particles and releases chemical additives that enter the water. Microplastic contamination is documented globally in both marine and freshwater environments, posing a significant threat to aquatic ecosystems. The small size of these particles makes them susceptible to ingestion by low trophic fauna, a trend expected to escalate. Ingestion leads to adverse effects like intestinal blockages, alterations in lipid metabolism, histopathological changes in the intestine, contributing to the extinction of vulnerable species and disrupting ecosystem balance. Notably, microplastics (MPs) can act as carriers for pathogens, potentially causing impaired reproductive activity, decreased immunity, and cancer in various organisms. Studies have identified seven principal sources of MPs, including synthetic textiles (35%) and tire abrasion (28%), highlighting the significant human contribution to this pollution. This review covers various aspects of microplastic pollution, including sources, extraction methods, and its profound impact on ecosystems. Additionally, it explores preventive measures, aiming to guide researchers in selecting techniques and inspiring further investigation into the far-reaching impacts of microplastic pollution, fostering effective solutions for this environmental challenge.

Retention of ZnO nanoparticles onto polypropylene and polystyrene microplastics: Aging-associated interactions and the role of aqueous chemistry

Microplastics (MPs) are pervasive and undergo environmental aging processes, which alters potential interaction with the co-contaminants. Hence, to assess their contaminant-carrying capacity, mimicking the weathering characteristics of secondary MPs is crucial. To this end, the present study investigated the interaction of Zinc oxide (nZnO) nanoparticles with non-irradiated (NI) and UV-irradiated (UI) forms of the most abundant MPs, such as polypropylene (PP) and polystyrene (PS), in aqueous environments. SEM images revealed mechanical abrasions on the surfaces of NI-MPs and their subsequent photoaging caused the formation of close-ended and open-ended cracks in UI-PP and UI-PS, respectively. Batch-sorption experiments elucidated nZnO uptake kinetics by PP and PS MPs, suggesting a sorption-desorption pathway due to weaker and stronger sorption sites until equilibrium was achieved. UI-PP showed higher nZnO (∼3000 mg/kg) uptake compared to NI-PP, while UI-PS showed similar or slightly decreased nZnO (∼2000 mg/kg) uptake compared to NI-PS. FTIR spectra and zeta potential measurements revealed electrostatic interaction as the dominant interaction mechanism. Higher nZnO uptake by MPs was noted between pH 6.5 and 8.5, whereas it decreased beyond this range. Despite DOM, MPs always retained ∼874 mg/kg nZnO irrespective of MPs type and extent of aging. The experimental results in river water showed higher nZnO uptake on MPs compared to DI water, attributed to mutual effect of ionic competition, DOM, and MP hydrophobicity. In the case of humic acids, complex synthetic and natural water matrices, NI-MPs retained more nZnO than UI-MPs, suggesting that photoaged MPs sorb less nZnO under environmental conditions than non-photoaged MPs. These findings enhance our understanding on interaction of the MPs with co-contaminants in natural environments.

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.

Characteristics and quantification of small microplastics (<100 µm) in seasonal svalbard snow on glaciers and lands

Small microplastics (SMPs < 100 µm) can easily be transported over long distances far from their sources through the atmospheric pathways and reach even remote regions, including the Arctic. However, these sizes of MPs are mostly overlooked due to different analytical challenges; besides, their pathways through atmospheric depositions, such as snow depositions, are mostly unknown. The spatial variability in bulk snow samples was investigated for the first time in distinct sites (e.g., glaciers) near Ny Ålesund, the world-known northernmost permanent research settlement in the Svalbard Islands, to better comprehend the presence of SMP pollution in snow. Seasonal snow deposited over the tundra and the summits of different glaciers were also sampled. A sampling procedure was designed to obtain representative samples while minimizing plastic contamination, thanks to rigorous quality assurance and quality control protocol. SMPs' weight (µg SMP L-1) and deposition load (mg SMPs m-2) result from being lower in the remote glaciers, where they may be subject to long-range transport. The SMPs' minimum length was 20 µm, with the majority less than 100 µm. Regarding their size distribution, there was an increase in the size length deriving from the local input of the human presence near the scientific settlement. The presence of some polymers might be site-specific in relation to the pathways that affect their distribution at the sites studied. Also, from the snow surface layer collected at the same sites to evaluate the variability of SMPs during specific atmospheric deposition events, the results confirmed their higher weight and load in surface snow near the scientific settlement compared to the glaciers. The results will enhance the limited knowledge of the SMPs in polar atmospheric compartments and deposition processes.

Integrated biomarker responses in wild populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic pressures

Bunodosoma zamponii is the most abundant anemone in Mar del Plata (Buenos Aires, Argentina). Given that the presence of persistent organic pollutants (organochlorine pesticides and PCBs) and the organophosphate pesticide chlorpyrifos has recently been reported in this species, two wild populations living under different anthropogenic pressures were studied and compared regarding basic aspects of their ecology and physiological response to oxidative stress. A population from an impacted site (Las Delicias, LD) and another from a reference site (Punta Cantera, PC) were monitored seasonally (spring, summer, autumn, and winter), for one year. Anemones from PC were larger and more abundant than those from LD for most sampling periods. During winter, glutathione-S-transferase and catalase activities were higher in LD. Moreover, protein content and antioxidant defenses were higher in anemones from PC during winter as well. Taking into account their ecology (size and abundance) and biomarker responses, the population from PC was comparatively healthier. Furthermore, such differences are in agreement with recent studies indicating a higher concentration of pollutants in anemones from LD (specially during the winter sampling). In this sense, considering that B. zamponii can bioaccumulate the aforementioned pollutants, its resilience to their presence, and the fact that biomarker response differed between sites, this species can be regarded as a proper sentinel species of environmental pollution. Overall, this anemone seems to be a good bioindicator to be considered in future biomonitoring and ecotoxicological studies.

Research advances on the toxicity of biodegradable plastics derived micro/nanoplastics in the environment: A review

The detrimental effects of plastic and microplastic accumulation on ecosystems are widely recognized and indisputable. The emergence of biodegradable plastics (BPs) offers a practical solution to plastic pollution. Problematically, however, not all BPs can be fully degraded in the environment. On the contrary, the scientific community has demonstrated that BPs are more likely than conventional plastics (CPs) to degrade into micro/nanoplastics and release additives, which can have similar or even worse effects than microplastics. However, there is very limited information available on the environmental toxicity assessment of BMPs. The absence of a toxicity evaluation system and the uncertainty regarding combined toxicity with other pollutants also impede the environmental toxicity assessment of BMPs. Currently, research is focused on thoroughly exploring the toxic effects of biodegradable microplastics (BMPs). This paper reviews the pollution status of BMPs in the environment, the degradation behavior of BPs and the influencing factors. This paper comprehensively summarizes the ecotoxicological effects of BPs on ecosystems, considering animals, plants, and microorganisms in various environments such as water bodies, soil, and sediment. The focus is on distinguishing between BMPs and conventional microplastics (CMPs). In addition, the combined toxic effects of BMPs and other pollutants are also being investigated. The findings suggest that BMPs may have different or more severe impacts on ecosystems. The rougher and more intricate surface of BMPs increases the likelihood of causing mechanical damage to organisms and breaking down into smaller plastic particles, releasing additives that lead to a series of cascading negative effects on related organisms and ecosystems. In the case of knowledge gaps, future research is also proposed and anticipated to investigate the toxic effects of BMPs and their evaluation.

Microplastics Prevalence in Different Cetaceans Stranded along the Western Taiwan Strait

Microplastics (MPs) pollution is of global concern, which poses serious threats to various marine organisms, including many threatened apex predators. In this study, MPs were investigated from nine cetaceans of four different species, comprising one common dolphin (Delphinus delphis), two pygmy sperm whales (Kogia breviceps), one ginkgo-toothed beaked whale (Mesoplodon ginkgodens), and five Indo-Pacific humpback dolphins (Sousa chinensis) stranded along the western coast of the Taiwan Strait from the East China Sea based on Fourier transform infrared (FTIR) spectroscopy analysis. Mean abundances of 778 identified MPs items were 86.44 ± 12.22 items individual-1 and 0.43 ± 0.19 items g-1 wet weight of intestine contents, which were found predominantly to be transparent, fiber-shaped polyethylene terephthalate (PET) items usually between 0.5 and 5 mm. The abundance of MPs was found at a slightly higher level and significantly correlated with intestine contents mass (p = 0.0004*). The MPs source was mainly likely from synthetic fibers-laden sewage discharged from intense textile industries. Our report represents the first study of MPs in pelagic and deep-diving cetaceans in China, which not only adds baseline data on MPs for cetaceans in Asian waters but also highlights the further risk assessment of MPs consumption in these threatened species.

Distribution and characteristics of microplastics in 16 benthic organisms in Haizhou Bay, China: Influence of habitat, feeding habits and trophic level

Microplastics (MPs) are widely found in the ocean and cause a serious risk to marine organisms. However, fewer studies have been conducted on benthic organisms. This study conducted a case study on the pollution characteristics of MPs on 16 marine benthic organisms in Haizhou Bay, and analyzed the effects of habitat, trophic level, and feeding mode on the MPs pollution characters. The results showed that MPs were detected in all 16 organisms with an average abundance of 8.84 ± 9.14 items/individual, which is in the middle-high level in the international scale. Among the detected MPs, the main material was cellophane. This study showed that benthic organisms can be used as indicator organisms for MPs pollution. MPs in organisms can be affected by their habitat, trophic level, and feeding mode. Comprehensive analysis of MPs in benthic organisms will contribute to fully understand the characterization and source resolution of MPs pollution.

Effects of microplastics, pesticides and nano-materials on fish health, oxidative stress and antioxidant defense mechanism

Microplastics and pesticides are emerging contaminants in the marine biota, which cause many harmful effects on aquatic organisms, especially on fish. Fish is a staple and affordable food source, rich in animal protein, along with various vitamins, essential amino acids, and minerals. Exposure of fish to microplastics, pesticides, and various nanoparticles generates ROS and induces oxidative stress, inflammation, immunotoxicity, genotoxicity, and DNA damage and alters gut microbiota, thus reducing the growth and quality of fish. Changes in fish behavioral patterns, swimming, and feeding habits were also observed under exposures to the above contaminants. These contaminants also affect the Nrf-2, JNK, ERK, NF-κB, and MAPK signaling pathways. And Nrf2-KEAP1 signalling modulates redox status marinating enzymes in fish. Effects of pesticides, microplastics, and nanoparticles found to modulate many antioxidant enzymes, including superoxide dismutase, catalase, and glutathione system. So, to protect fish health from stress, the contribution of nano-technology or nano-formulations was researched. A decrease in fish nutritional quality and population significantly impacts on the human diet, influencing traditions and economics worldwide. On the other hand, traces of microplastics and pesticides in the habitat water can enter humans by consuming contaminated fish which may result in serious health hazards. This review summarizes the oxidative stress caused due to microplastics, pesticides and nano-particle contamination or exposure in fish habitat water and their impact on human health. As a rescue mechanism, the use of nano-technology in the management of fish health and disease was discussed.

Occurrence and Characteristics of Microplastics in Wild and Farmed Shrimps Collected from Cau Hai Lagoon, Central Vietnam

This study investigated the occurrence of microplastics (MPs) in the gastrointestinal tracts (GT) and tissues of four common shrimps (including two wild-caught shrimps and two farmed shrimps) collected from a high-diversity lagoon in central Vietnam. The numbers of MP items in greasy-back shrimp (Metapenaeus ensis), green tiger shrimp (Penaeus semisulcatus), white-leg shrimp (Litopenaeus vannamei), and giant tiger shrimp (Penaeus monodon), determined per weight and individual, were 0.7 ± 0.3, 0.6 ± 0.2, 1.1 ± 0.4, and 0.5 ± 0.3 (items/g-ww), and 2.5 ± 0.5, 2.3 ± 0.7, 8.6 ± 3.5, 7.7 ± 3.5 (items/individual), respectively. The concentration of microplastics in the GT samples was significantly higher than that in the tissue samples (p < 0.05). The number of microplastics in the farmed shrimp (white-leg shrimp and black tiger shrimp) was statistically significantly higher than the number of microplastics in the wild-caught shrimp (greasy-back and green tiger shrimps) (p <0.05). Fibers and fragments were the dominant shapes of the MPs, followed by pellets, and these accounted for 42-69%, 22-57%, and 0-27% of the total microplastics, respectively. The chemical compositions determined using FTIR confirmed six polymers, in which rayon was the most abundant polymer, accounting for 61.9% of the MPs found, followed by polyamide (10.5%), PET (6.7%), polyethylene (5.7%), polyacrylic (5.8%), and polystyrene (3.8%). As the first investigation on the MPs in shrimps from Cau Hai Lagoon, central Vietnam, this study provides useful information on the occurrences and characteristics of the microplastics in the gastrointestinal tracts and tissues of four shrimp species that live in different living conditions.

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.

A global snapshot of microplastic contamination in sediments and biota of marine protected areas

Microplastics (MPs) become ubiquitous contaminants in Marine Protected Areas (MPA) that have been planned as a conservation strategy. The present study provides a comprehensive overview of the occurrence, abundance, and distribution of MPs potentially affecting MPA worldwide. Data on MP occurrence and levels in sediment and biota samples were collected from recent peer-reviewed literature and screened using a GIS-based approach overlapping MP records with MPA boundaries. MPs were found in 186 MPAs, with levels ranging from 0 to 9187.5 items/kg in sediment and up to 17,461.9 items/kg in organisms. Peaked MPs concentrations occurred within multiple-use areas, and no-take MPAs were also affected. About half of MP levels found within MPA fell into the higher concentration quartiles, suggesting potential impacts on these areas. In general, benthic species were likely more affected than pelagic ones due to the higher concentrations of MP reported in the tissues of benthic species. Alarmingly, MPs were found in tissues of two threatened species on the IUCN Red List. The findings denote urgent concerns about the effectiveness of the global system of protected areas and their proposed conservation goals.

First evidence of meso- and microplastics on the mangrove leaves ingested by herbivorous snails and induced transcriptional responses

Although evidence suggests the ubiquity of meso- and microplastics (MMPs) in mangrove forests, our knowledge of their bioavailability and risk on mangrove leaves is scarce. Here, we investigated MMP contamination concerning submerged mangrove leaves and herbivorous snails that mainly feed on them from the four mangrove forests located in Beibu Gulf, Guangxi Province, China. Results showed that the MMP abundance on the mangrove leaves ranged from 0.01 ± 0.00 to 0.42 ± 0.15 items cm^-2, while it ranged from 0.33 ± 0.21 to 6.20 ± 2.91 items individual^-1 in the snails. There were significant positive correlations between snails and leaves regarding the abundance of total MMPs and the proportions of MMPs with the same characteristics. Expanded polystyrene (EPS) that mainly derived from aquaculture rafts, accounted for a major component both on the leaves and in the snails in Shi Jiao (SJ). Both the detection frequency and percentage of larger EPS (2.00-17.50 mm) on the leaves in SJ were higher than other sites. Meanwhile, the detection frequency, abundance and percentage of larger EPS on the leaves had significant positive correlations with those of micro-EPS in the snails. These findings suggested that mangrove leaves may represent a viable pathway for MMPs to enter the herbivorous snails. Larger EPS with higher frequency of occurrence on mangrove leaves were more likely to be encountered and ingested by snail considering its opportunistic feeding behavior. In addition, 11 sensitive genes involved in the processes of metabolism, intestinal mucosal immune systems, and cellular transduction in the snails were significantly suppressed by MMP exposure, which may be potentially used as early biomarkers to indicate the biological effects of MMPs under realistic environmental conditions. Overall, this study provides novel insights into the fate, sources, and biological effects of MMPs on mangrove leaves.

The Phenomenon of Antibiotic Resistance in the Polar Regions: An Overview of the Global Problem

The increasing prevalence of antibiotic resistance is a global problem in human and animal health. This leads to a reduction in the therapeutic effectiveness of the measures used so far and to the limitation of treatment options, which may pose a threat to human health and life. The problem of phenomenon of antibiotic resistance affects more and more the polar regions. This is due to the increase in tourist traffic and the number of people staying at research stations, unmodernised sewage systems in inhabited areas, as well as the migration of animals or the movement of microplastics, which may contain resistant bacteria. Research shows that the presence of antibiotic resistance genes is more dominant in zones of human and wildlife influence than in remote areas. In a polluted environment, there is evidence of a direct correlation between human activity and the spread and survival of antibiotic-resistant bacteria. Attention should be paid to the presence of resistance to synthetic and semi-synthetic antibiotics in the polar regions, which is likely to be correlated with human presence and activity, and possible steps to be taken. We need to understand many more aspects of this, such as bacterial epigenetics and environmental stress, in order to develop effective strategies for minimizing the spread of antibiotic resistance genes. Studying the diversity and abundance of antibiotic resistance genes in regions with less anthropogenic activity could provide insight into the diversity of primary genes and explain the historical evolution of antibiotic resistance.

Uptake of microplastics by the snakelocks anemone (Anemonia viridis) is commonplace across environmental conditions

Microplastics (<1 mm) are ubiquitous in our oceans and widely acknowledged as concerning contaminants due to the multi-faceted threats they exert on marine organisms and ecosystems. Anthozoans, including sea anemones and corals, are particularly at risk of microplastic uptake due to their proximity to the coastline, non-selective feeding mechanisms and sedentary nature. Here, the common snakelocks anemone (Anemonia viridis) was used to generate understanding of microplastic uptake in the relatively understudied Anthozoa class. A series of microplastic exposure and multi-stressor experiments were performed to examine particle shape and size selectivity, and to test for the influence of food availability and temperature on microplastic uptake. All A. viridis individuals were found to readily take up microplastics (mean 142.1 ± 83.4 particles per gram of tissue) but exhibited limited preference between different particle shapes and sizes (n = 32). Closer examination identified that uptake involved both ingestion and external tissue adhesion, where microplastics were trapped in secreted mucus. Microplastic uptake in A. viridis was not influenced by the presence of food or elevated water temperature (n = 40). Furthermore, environmental sampling was performed to investigate microplastic uptake in A. viridis (n = 8) on the coast of southwest England, with a mean of 17.5 ± 4.0 particles taken up per individual. Fibres represented the majority of particles (91%) followed by fragments (9%), with 87% either clear, blue or black in colour. FTIR analysis identified 70% of the particles as anthropogenic cellulosic or plastic polymers. Thus, this study provides evidence of microplastic uptake by A. viridis in both laboratory exposures experiments and in the marine environment. These findings support recent literature suggesting that external adhesion may be the primary mechanism in which anthozoans capture microplastics from the water column and highlights the potential role anemones can play as environmental microplastic bioindicators.

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.

Environmentally relevant concentrations of microplastics modulated the immune response and swimming activity, and impaired the development of marine medaka Oryzias melastigma larvae

Microplastics (MPs), due to their impacts on the ecosystem and their integration into the food web either through trophic transfer or ingestion directly from the ambient environment, are an emerging class of environmental contaminants posing a great threat to marine organisms. Most reports on the toxic effects of MPs exclusively focus on bioaccumulation, oxidative stress, pathological damage, and metabolic disturbance in fish. However, the collected information on fish immunity in response to MPs is poorly defined. In particular, little is known regarding mucosal immunity and the role of mucins. In this study, marine medaka (Oryzias melastigma) larvae were exposed to 6.0 µm beads of polystyrene microplastics (PS-MPs) at three environmentally relevant concentrations (10² particles/L, 10⁴ particles/L, and 10⁶ particles/L) for 14 days. The experiment was carried out to explore the developmental and behavioural indices, the transcriptional profiles of mucins, pro-inflammatory, immune, metabolism and antioxidant responses related genes, as well as the accumulation of PS-MPs in larvae. The results revealed that PS-MPs were observed in the gastrointestinal tract, with a concentration- and exposure time-dependent manner. No significant difference in the larval mortality was found between the treatment groups and the control, whereas the body length of larvae demonstrated a significant reduction at 10⁶ particles/L on 14 days post-hatching. The swimming behaviour of the larvae became hyperactive under exposure to 10⁴ and 10⁶ particles/L PS-MPs. In addition, PS-MP exposure significantly up-regulated the mucin gene transcriptional levels of muc7-like and muc13-like, however down-regulated the mucin gene expression levels of heg1, muc2, muc5AC-like and muc13. The immune- and inflammation and metabolism-relevant genes (jak, stat-3, il-6, il-1β, tnf-а, ccl-11, nf-κb, and sod) were significantly induced by PS-MPs at 10⁴ and 10⁶ particles/L compared to the control. Taken together, this study suggests that PS-MPs induced inflammation response and might obstruct the immune functions and retarded the growth of the marine medaka larvae even at environmentally relevant concentrations.

Occurrence and Characterization of Small Microplastics (<100 μm), Additives, and Plasticizers in Larvae of Simuliidae

This study is the first to investigate the ingestion of microplastics (MPs), plasticizers, additives, and particles of micro-litter < 100 μm by larvae of Simuliidae (Diptera) in rivers. Blackflies belong to a small cosmopolitan insect family whose larvae are present alongside river courses, often with a torrential regime, up to their mouths. Specimens of two species of blackfly larvae, Simulium equinum and Simulium ornatum, were collected in two rivers in Central Italy, the Mignone and the Treja. Small microplastics (SMPs, <100 μm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs) ingested by blackfly larvae were, for the first time, quantified and concurrently identified via MicroFTIR. The pretreatment allowed for simultaneous extraction of the ingested SMPs and APFs. Strong acids or strong oxidizing reagents and the application of temperatures well above the glass transition temperature of polyamide 6 and 6.6 (55−60 °C) were not employed to avoid further denaturation/degradation of polymers and underestimating the quantification. Reagent and procedural blanks did not show any SMPs or APFs. The method’s yield was >90%. Differences in the abundances of the SMPs and APFs ingested by the two species under exam were statistically significant. Additives and plasticizers can be specific to a particular polymer; thus, these compounds can be proxies for the presence of plastic polymers in the environment.

Plastics, prawns, and patterns: Microplastic loadings in Nephrops norvegicus and surrounding habitat in the North East Atlantic

The presence of microplastics (MPs), a contaminant of emerging concern, has attracted increasing attention in commercially important seafood species such as Nephrops norvegicus. This species lend themselves well as bioindicators of environmental contamination owing to their availability, spatial and depth distribution, interactions with seafloor sediment and position in the ecosystem and food chain. This study assesses the abundance of MPs in N. norvegicus and in benthic sediments across six functional units in the North East Atlantic. Assessment of the relationship between MP abundance in N. norvegicus, their biological parameters and their surrounding environment was examined. Despite the lack of statistical significance, MP abundances, size, shape, and polymer type recorded in N. norvegicus mirrored those found in the surrounding environment samples. The three main polymers identified in both organisms and sediment were polystyrene, polyamide (nylons), and polypropylene. The level of MP contamination in N. norvegicus could be related to local sources, with relatively low abundances recorded in this study for the North East Atlantic in comparison to other regional studies. Furthermore, larger organisms contained a lower abundance of MPs, demonstrating no accumulation of MPs in N. norvegicus. Based on the results of this study, data on MP ingestion could be used to study trends in the amount and composition of litter ingested by marine animals towards fulfilling requirements of descriptor 10 of the Marine Strategy Framework Directive.

Occurrence of polychlorinated biphenyls (PCBs) in the sea anemone Bunodosoma zamponii, sediments and seawater from the southwestern Atlantic

Polychlorinated biphenyls (PCBs) are persistent and bioaccumulable organic compounds. The occurrence of PCBs was assessed in two populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic strains. One location was in vicinity to a wastewater plant (Las Delicias, LD), and the other was a preserved location chosen as a reference site (Punta Cantera, PC). Anemone populations were sampled 4 times (spring, summer, autumn and winter) throughout a year, in addition to seawater and sediment from those areas. PCB loadings ranged from 2.89 to 79.41 ng L^-1 in seawater samples and from 0.07 to 6.61 ng g^-1 dry weight in sediment samples. Total PCB levels ranged from 0.22 to 14.94 and 2.79 to 24.69 ng g^-1 wet weight in anemones from PC and LD, respectively. PCBs concentrations in anemones from LD were significantly greater than PC during spring, summer and winter. The congeners 18 and 44 prevailed in seawater samples, 44 and 52 in sediment and 18 and 132+153 in anemones. Redundancy analysis integrated PCB levels from all matrixes and bolstered contrast between sampling sites. Seasonality was also a relevant factor since during winter PCB loading was greater in sediment and anemone samples, coincident with the rainiest season. Disparity between sites could be due to LD's proximity to the wastewater plant, effect of littoral drift direction and/or asymmetries in anemones physiological condition.

Microplastics in decapod crustaceans sourced from Australian seafood markets

Microplastic abundance and characteristics were assessed in five decapod crustaceans purchased from seafood markets and collected in coastal waters around Australia (South Australia, New South Wales, Queensland, Northern Territory, and Western Australia). Three species of prawns (king, banana and tiger prawns) and two species of crabs (blue-swimmer and mud crabs) were analysed. Muscle tissues and gastro-intestinal tracts in prawns, and gastro-intestinal tracts in crabs, were chemically digested, with microplastic identification verified using Fourier Transform Infrared spectroscopy. Forty-eight percent of crustaceans contained microplastics. Prawns and crabs had 0.8 ± 0.1 and 1.6 ± 0.1 pieces per individual, respectively, with spatial patterns evident. Microplastics were predominantly fibres (98%) of blue (58%) and black (24%) colours with polyolefin including polyester the most prevalent polymers. Overall, compared to a systematic review we performed of microplastics in decapod crustaceans worldwide, microplastic loads in crustaceans from Australia were in the lower range of plastic contamination.

Microplastic pollution in wild populations of decapod crustaceans: A review

Along with the increasing amount of plastic production and waste disposal, the presence of microplastics has been confirmed in all compartments of ecosystems. The microplastics in biota is of particular concern due to the potential eco-risks associated with long term exposure and the potential for transportation along food webs. Decapoda represents a diverse taxonomic group within the subphylum Crustacea, and some of which are highly valued in fishery and biological production. The interaction between microplastic pollution and wild populations of decapod crustaceans have been documented less than fish or bivalves but are critical to understand the fates of microplastics in marine eco-systems and enrich the baselines for consumption analyses. Our review systematically summarizes the occurrence, abundance and characteristics of microplastics detected in edible and non-edible sections of decapod crustaceans from field observations. Sub-groups between crabs and shrimps were also included for comparison. The occurrence of microplastics in the edible sections were less than those in non-edible sections, and there are differences between crabs and shrimps. Fibrous microplastics and items with a size category less than 1 mm were dominant pollutants across all available literature. The methodology selection, biological features and uptake pathways play roles in the microplastic body burden in Decapoda. Our work enriches the understanding of microplastic pollution in wild populations of decapod crustaceans but their contribution to the human exposure to microplastics needs to be addressed with more accurate measurements.

Organochlorine pesticides and chlorpyrifos in the sea anemone Bunodosoma zamponii (Actiniaria: Actiniidae) from Argentina's southeastern coast

Temporal and spatial distribution of organochlorine pesticides (OCPs) and the organophosphate pesticide chlorpyrifos, one of the main insecticides used in Argentina, was evaluated in two populations of the sea anemone Bunodosoma zamponii living under different anthropological stressors: Las Delicias (LD) adjacent to a wastewater plant, and Punta Cantera (PC) a reference site. Pesticides were analyzed throughout the year in water, sediments and whole organisms. Chlorpyrifos represented 50% of the total pesticide found in water samples during winter. HCHs and drins were predominant in sediment samples, mainly in LD. Total pesticide concentration in anemones from LD was higher than those from PC during winter (mainly associated with HCHs, endosulfans, DDTs and chlorpyrifos levels), coincident with the main period of effluent discharge to the coast after pesticide applications and also the rainiest season. Dissimilarities among anemones populations could stem from a differential input of pesticides in each site and/or a contrasting physiological status of the populations.

Microplastics in beluga whale (Delphinapterus leucas) prey: An exploratory assessment of trophic transfer in the Beaufort Sea

Microplastics (MPs, <5 mm in length) have been identified as emerging contaminants in marine environments, with ingestion by a variety of biota being of increasing concern. Few studies exist on MP ingestion in Arctic fish, and there are currently no such data from the Beaufort Sea. We investigated MP abundance in five ecologically valuable species from three sampling sites in the Eastern Beaufort Sea to evaluate possible trophic-level pathways of MPs from prey to beluga whales. Polymer analysis confirmed that 21% of fish gastrointestinal tracts (n = 116) contained microplastic particles. Fish that contained MPs had a mean abundance of 1.42 ± 0.44 particles per individual and an overall mean abundance of 0.37 ± 0.16 particles. No plastic particles >5 mm were found, and 78% of the particles observed were fibers. Based on energetic needs, we estimate that individual beluga may ingest between 3800 and 145,000 microplastics annually through trophic transfer, with uncertain health implications.

Spatio-temporal variation of microplastic pollution in the sediment from the Chukchi Sea over five years

Sediment has been considered as an important sink for microplastics (MPs), but there are limited reports about the spatial and temporal variability of MPs in sediment from the Arctic Ocean. Furthermore, understanding is lacking on the correlation between Arctic sea ice variation and MP abundance in sediment. This study aimed to assess the MP contamination in the sediment from the Chukchi Sea over five years through three voyages (in 2016, 2018, and 2020). The MP abundances in the sediments from the Chukchi Plateau and Chukchi Shelf over five years ranged from 33.66 ± 15.08 to 104.54 ± 28.07 items kg^-1 dry weight (DW) and 20.63 ± 6.71 to 55.64 ± 22.61 items kg^-1 DW, respectively. The MP levels from the Chukchi Sea were lower than those from the Eastern Arctic Ocean. Our findings suggest that the Chukchi Plateau is an accumulation zone for fibers related to fishing gear and textiles under the dual influence of the Pacific and Atlantic Ocean currents. However, the reduction of these fibers in the sediment from the Chukchi Shelf might be related to bottom currents, sediment resuspension, and biomass. Moreover, the MP abundance in the sediment from the Chukchi Sea was positively correlated with the reduction of Arctic sea ice, suggesting that the melting sea ice contributes to the increase in MP levels in the sediment. The increase in blue MPs from the Chukchi Plateau over time might be attributed to melting sea ice or intense fishing activity, whereas the increase of the smallest MPs in this region could be owing to the breakdown of larger plastics during long-distance transport or the easier settlement of smaller MPs. Further time-series investigations are urgently required to improve the understanding of the environmental fate and transport of MPs among the different Arctic environmental compartments.

Dangerous microplastics in topshells and anemones along the north coast of Spain

While levels of microplastics and other pollutants keep increasing in all coastal habitats, seafood is being eaten all over the world. In this research, three edible species were sampled from six points along the central north coast of Spain: Actinia equina anemones and Phorcus lineatus and Steromphala umbilicaris topshells (N = 100). Putative microplastics (N = 2157) were identified, counted, and many analyzed through FT-IR spectroscopy. Herbivorous topshells contained significantly more microplastics than carnivorous anemones. The most common particles were fibers, with transparent, blue and black as most prominent colours. Plastics included PE, polyester, PET, PP, nylon, PS, PVB and acrylic fibers. The sampled items contained several harmful compounds, including PTTC of which even one particle could be fatal if inhaled. This highlights the urgent need for studies regarding the safety of seafood.

Micro- and nanoplastic transfer in freezing saltwater: implications for their fate in polar waters

Plastic debris accumulates in the Arctic by way of oceanic and atmospheric circulation. High concentrations of microplastics (1 μm to 5 mm) have been measured, and nanoplastics (<1 μm) are expected to be abundant as well. However, little is known about the mobility of micro- and nanoplastics at the seawater/ice interface. This study investigates the fate of micro- and nanoplastics during sea-ice formation. A novel experimental approach simulates the growth of sea ice by progressively freezing a saline solution. After different durations of freezing, the concentrations of NaCl, natural organic matter, microplastics, and nanoplastics were measured in the ice and liquid. Micro- and nanoplastic distribution coefficients between saltwater and ice were determined, reflecting their behavior during congelation sea-ice growth. The results show that microplastics are retained in ice while nanoplastics are expulsed from it. Furthermore, natural organic matter plays a crucial role in stabilizing nanoplastics at this interface. These results raise new questions concerning the impact of micro- and nanoplastics in fragile polar environments and the analytical strategy to detect them.

Microbial colonizers of microplastics in an Arctic freshwater lake

Microplastics (MPs) have been found everywhere as they are easily transported between environmental compartments. Through their transport, MPs are quickly colonized by microorganisms; this microbial community is known as the plastisphere. Here, we characterized the plastisphere of three MPs, one biodegradable (PHB) and two non-biodegradables (HDPE and LDPE), deployed in an Arctic freshwater lake for eleven days. The plastisphere was found to be complex, confirming that about a third of microbial colonizers were viable. Plastisphere was compared to microbial communities on the surrounding water and microbial mats on rocks at the bottom of the lake. Microbial mats followed by MPs showed the highest diversity regarding both prokaryotes and eukaryotes as compared to water samples; however, for fungi, MPs showed the highest diversity of the tested substrates. Significant differences on microbial assemblages on the three tested substrates were found; regarding microbial assemblages on MPs, bacterial genera found in polar environments such as Mycoplana, Erythromicrobium and Rhodoferax with species able to metabolize recalcitrant chemicals were abundant. Eukaryotic communities on MPs were characterized by the presence of ciliates of the genera Stentor, Vorticella and Uroleptus and the algae Cryptomonas, Chlamydomonas, Tetraselmis and Epipyxis. These ciliates normally feed on algae so that the complexity of these assemblages may serve to unravel trophic relationships between co-existing taxa. Regarding fungal communities on MPs, the most abundant genera were Betamyces, Cryptococcus, Arrhenia and Paranamyces. MPs, particularly HDPE, were enriched in the sulI and ermB antibiotic resistance genes (ARGs) which may raise concerns about human health-related issues as ARGs may be transferred horizontally between bacteria. This study highlights the importance of proper waste management and clean-up protocols to protect the environmental health of pristine environments such as polar regions in a context of global dissemination of MPs which may co-transport microorganisms, some of them including ARGs.

Microplastics and food shortage impair the byssal attachment of thick-shelled mussel Mytilus coruscus

Microplastics (MPs) have become a ubiquitous emerging pollutant in the global marine environment. The potential toxic effects of MPs and interactions of MP pollution with other stressors such as food limitation on marine organisms' health are not yet well understood. This study investigated the effects of three-week exposure to different MPs and food shortage on the physical defense mechanisms (byssus production and properties) of Mytilus coruscus. Starvation significantly reduced the number of byssus threads, and combined exposure to MPs and food shortage suppressed the adhesion ability and condition index of mussels. The length of the byssus threads was not affected by all experimental exposures. Transcript levels of genes encoding key proteins involved in byssus formation (the mussel foot proteins mfp-1, -2, -3, -4, -5 and -6, and prepolymerized collagen proteins preCOL-D, -P and -NG) were altered by interactions between the MPs and food shortage. These findings show that insufficient food supply can exacerbate the adverse effects of MPs on mussel defense which might have implications for survival and fitness of mussels under food limited conditions (e.g. in winter) in polluted coastal habitats.

Distribution and characteristics of microplastics in the basin of Chishui River in Renhuai, China

As an emerging pollutant, microplastics widely exist in rivers all over the world. Due to the differences of economic development, economic structure and population in different regions, the abundance of microplastics in rivers is different. In those areas where agriculture is developed, the content of film microplastics is more, while in densely populated areas, the content of fibrous microplastics is more. Taking Renhuai Basin of Chishui River as the research object, the pollution characteristics and current situation of microplastics in the basin were analyzed, and the contamination risk of microplastics was evaluated. The abundance of microplastics in Renhuai basin of Chishui River ranges from 1.77 to 14.33 items/L. The main forms of microplastics were fibrous (59.4%), white (including transparent) (41.3%) and polychromatic (44.1%). The particle size of microplastics was mainly 500- 1000 μm (63.9%). According to the assessment, the risk of microplastics in the basin is 111.79, which is a secondary risk area. This study can provide a further reference for understanding the pollution characteristics of microplastics in rivers.

Source and risk assessment of heavy metals and microplastics in bivalves and coastal sediments of the Northern Persian Gulf, Hormogzan Province

The objectives of the current study are to investigate the concentration, biological risks, chemical speciation, and mobility of of heavy metals and also the determination of their distribution, physicochemical characteristics, and abundance of microplastics in coastal sediments and edible bivalves in the Persian Gulf, the coastal area of Hormozgan Province. Sampling points were selected considering the location of industrial, urban and Hara forest protected areas. In November 2017, a total of 18 sediment samples from coastal sediments (top 0-10 cm) and the most consumed bivalve species in the region were collected from two stations, Lengeh and Bandar Abbas Ports. The average concentration of heavy metals (except for Ni and Cd) in the sediments were lower than their average shale and the upper continental crust. Enrichment factors revealed significant enrichment of Ni, Mn, Cr, Cd and As. The fractionation of heavy metals using the Community Bureau of Reference (BCR) sequential extraction scheme indicated the high bioavailability of Zn, As, Mn, and Co. In general, the highest concentration of Mo, Cd, Pb, Zn, Cr, Cu, Mn, Hg, and Sb was detected in areas with frequent human activities including Shahid Rajaee Port, Shahid Bahonar Port, and Tavanir station. Shahid Rajaee and Shahid Bahonar Ports are the most important ports on the coast of Hormozgan province. The Risk Assessment Code calculated for the study elements indicates that As, Co, Zn, and Cu pose a moderate environmental risk a threat to the aquatic biota. Health risks of most heavy metals arising from bivalves consumption were safe, except for As which is associated with the high target cancer risk values. With reference to the type of microplastics found, they were mainly fibeours with lengths ranging between 100 and 250 μm in sediments and bivalves. Most of the microfibers found in the sediments were made of polyethylene terephthalate (PET) and polypropylene (PP), and the fibers found in the bivalves were made of PP.