Presence and characterization of microplastics in fish of commercial importance from the Biobío region in central Chile

Quantification and characterization of microplastics ingested by mangrove oysters across West Africa

Microplastic ingestion by marine organisms presents a challenge to both ecosystem functioning and human health. We characterized microplastic abundance, shape, size, and polymer types ingested by the West African mangrove oyster, Crassostrea tulipa (Lamarck, 1819) sampled from estuaries and lagoons from the Gambia, Sierra Leone, Ghana, Benin, and Nigeria using optical microscopy and Fourier transform infrared (FTIR) techniques. A total of 780 microplastics were isolated in the whole tissues of the 250 oysters (n = 50 oysters per country). The abundance and distribution of microplastics in the oysters followed the pattern: the Gambia > Ghana > Sierra Leone > Nigeria > Benin. The Tanbi wetlands in the Gambia recorded the highest average of 10.50 ± 6.69 per oyster while the Ouidah lagoon in Benin recorded the lowest average of 1.80 ± 1.90 per oyster. Overall, microplastic numbers varied significantly (p < 0.05) among the five countries. Microfibers, particularly those within 1001-5000 μm size, dominated the total microplastic count with a few fragments and films. No spherical microplastics were isolated in the oysters. In the Sierra Leone and Benin oysters, fragments and films were absent in the samples. Microplastic between the 1001 and 5000 μm size class dominated the counts, followed by 501-1000 μm, 101-500 μm, and 51-100 μm. Five polymer groups namely polyethylene, polyester, nylon, polypropylene, and polyamide were identified across the five countries, with polyethylene occurring in oysters from all five countries and polyester occurring in all but the oysters from Nigeria. This diversity of polymers suggests varied sources of microplastics ingested by the studied oysters. The absence of microspheres across the five supports findings from other studies that they are the least ingested and highly egested by the oysters.

Detection of plastic, cellulosic micro-fragments and microfibers in Laternula elliptica from King George Island (Maritime Antarctica)

It is generally acknowledged that microplastic pollutants are prevalent in ocean waters and sediments across a range of tropical, temperate, subpolar, and polar regions. The waters surrounding King George Island are significantly impacted by human activities, particularly those related to scientific stations, fishing, and tourism. Organisms, such as Laternula elliptica, can be used as environmental monitors due to the likelihood that they will bioaccumulate pollutants. The goal of this study was to quantify and identify plastic and cellulosic micro-fragments and microfibers present in the soft body of clams (n = 21), collected from Fildes Bay near sewage and wastewater discharges. Plastic and cellulose microfragments and microfibers were counted, and their compositions were determined using FT-IR. All 21 individuals sampled contained fragments and fibers, with a total of 900 items detected (42.86 ± 25.36 mean ± SD items per individual), or 1.82 items g.wet mass-1. 58 % of items were cellulose and 22 % plastic. Considering the plastic polymer compositions, 28.57 % were polyethylene terephthalate (PET), 21.43 % acrylic, 14.29 % high-density polyethylene (HDPE), 14.29 % Polypropylene (PP), 7.14 % ultra-high drawn polyethylene filament (UHMWPE), 7.14 % polyester and 7.14 % Polyethylene. The quantities and prevalence of MP in L. elliptica were higher than those found in other Antarctic marine species, and even in bivalves from populated regions of the world. Our work assessed the pollution status of L. elliptica near an effluent of wastewater plants and found that 95 % of individuals displayed MP and 100 % microfibers that could impact their population.

Assessment of microplastic contamination in commercially available fishes

Plastics have widespread applications for human use, but their disposal poses a significant threat to living organisms and these plastics end up in the marine environment. They will be fragmented into small pieces as a result of ultraviolet exposure, climatic changes, and temperature changes; Microplastics (MPs) are plastics that are less than 5 mm in size. The level of MP (Microplastic) pollution in commercially harvested fish from different habitant in Vellore, India is currently unknown. Therefore, this study aimed to determine the presence and characteristics of ingested or inhaled MPs in marine and freshwater fishes highly consumed by the local population. Fish gills and gastrointestinal tracts were aseptically dissected and digested (30% hydrogen peroxide), then filtered and examined under a microscope for the presence of MPs. Further analysis was performed on the samples using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDAX). Of the samples analysed, a total of 875 MPs were recovered from 32 fishes, with 478 from marine fishes and 397 from freshwater fishes. The most common colours of the MPs were blue and black, while stereo microscopy analysis revealed that the majority of MPs were fibers (91%), followed by fragments (8%) and a small number of films. The ATR-FTIR analysis identified polyvinyl alcohol (39.76%), polyethylene (16.51%), methylcellulose (12.84%) and styrene (9.07%), as the predominant types of MPs in the fish samples. This study highlights the significant impact of MP pollution on marine ecosystems. The research provides insight into the nature and extent of MPs in fish from both marine and freshwater habitats, with an aim for policies and interventions aimed to reduce plastic pollution in the locality.

Spatial distribution of microplastics in a coastal upwelling region: Offshore dispersal from urban sources in the Humboldt Current System

In coastal waters, higher concentrations of microplastics (MPs) are generally related to densely populated and industrialized areas, but intense upwelling and offshore transport in the Eastern Boundary Upwelling Systems (EBUS) may influence this pattern. The Humboldt Current System (HCS) along the coast of northern-central Chile represents a perfect model to test whether the abundance of MP at the sea surface decreases with distance from land-based sources, e.g., river mouths, harbors, and submarine wastewater outfalls. The sea surface was sampled with a manta trawl to examine the abundance, composition, and distribution of floating MPs, and Generalized Additive Mixed Models (GAMMs) were performed to examine the relationship between MP abundance (particles km-2) and the distance to putative sources. MPs were found in all 57 net tows, with an average of ⁓120,000 MP km-2 and maximum values of ⁓1,500,000 MP km-2. The composition of MPs was dominated by fragments (>50% of the total count) and over 80% of all MPs were ≥1 mm. The combined effect of the various sources, spatially concentrated in urban areas, makes it difficult to distinguish their relative contributions, but the MP composition suggested that rivers are more important sources, followed by submarine wastewater outfalls and then harbors. A significant and steep negative relationship with the "distance to source" explained 15.2% of the variance of "MP abundance", suggesting rapid offshore displacement within the HCS. This is the first study to report this pattern along the edges of the South Pacific Subtropical Gyre (SPSG), revealing that continuous offshore transport of microplastic from land-based sources is occurring over large scales and contributing to the accumulation of microplastics in the center of the SPSG. However, the findings additionally suggested that processes at meso- and submeso-spatial scales (driven by geographic and seasonal variables) are disrupting the general pattern.

Evidence of plastic pollution from offshore oceanic sources in southern Chilean Patagonian fjords

The Chilean Patagonian fjords are globally renowned as one of the few remaining pristine environments on Earth; however, their ecosystems are under significant threat from climatic and anthropogenic pressures. Of particular concern is the lack of research into the impact of plastic pollution on the waters and biodiversity of these fjords. In this study, the marine environment of a secluded and sparsely populated fjord system in southern Patagonia was sampled to assess microplastics in seawater, beaches, bottom sediment, and zooplankton. Microplastics were found to be widespread across the water surface of the fjord, but with low abundances of 0.01 ± 0.01 particles m-3 (mean ± SD). The presence of microplastics in sedimentary environments (e.g., beaches and bottom sediments, 15.6 ± 15.3 and 9.8 ± 24 particles kg of dry sediment-1, respectively) provided additional evidence of plastic debris accumulation within the fjord system. Furthermore, microplastics were already bioavailable to key zooplankton species of the Patagonian food web (0.01 ± 0.02 particles individual-1), suggesting bioaccumulation. A comprehensive examination of potential microplastic inputs originating from coastal runoff, coupled with distribution of water masses, suggested minimal local contribution of microplastics to the fjord, strongly indicating that plastic litter is likely entering the area through oceanic currents. The composition and type of microplastics, primarily consisting of polyester fibers (approx. 60 %), provided further support for the proposed distant origin and transportation into the fjord by oceanographic drivers. These results raise significant concern as reveal that despite a lack of nearby population, industrial or agricultural activity, remote Patagonian fjords are still impacted by plastic pollution originating from distant sources. Prioritizing monitoring efforts is crucial for effectively assessing the future trends and ecological impact of plastic pollution in these once so-called pristine ecosystems.

Impacts of microplastic on fisheries and seafood security - Global analysis and synthesis

This review paper collected, collated, analysed, interpreted, synthesised, and documented the research investigations conducted on microplastic (MPs) pollution impacts on seafood organisms (including fish, sharks, shrimps, lobsters, crabs, oysters, mussels, and seaweeds) during the last ten years (2012-2022) covering fifty-seven locations/countries in the world. MPs contaminated 926 seafood species comprising 895 finfish, 09 crustaceans, 20 molluscs and 02 seaweeds. Seafood from Asia was found to be most contaminated with MPs. High MP contamination/ingestion was revealed in several seafood organisms. The ingestion of MPs can reduce fish growth and fish fitness, leading to reduced yield/fish production. Fish and seafood play a significant role in supporting the economy, employment, food sources, and livelihoods of people across the globe, which can be threatened due to the contamination of seafood organisms with MPs. MPs have bioaccumulated in fish skin, gills, stomachs, liver, intestine, and muscles as well as dry fish and canned fish. Hence, the consumption of MP-contaminated fresh fish, whole fish, dried fish or canned fish poses risks as it may be a pathway of MP transfer to humans. MPs can increase the health risks to seafood fish consumers since there is a probability that high risks pollutants adsorbed on MPs (heavy metals, pesticides, and oil compounds) can transfer to humans via the food chain. Several of the chemicals (heavy metals, DDT, PAHs) adsorbed onto MPs are carcinogenic. MPs have also been detected in fish meals, therefore, farmed livestock such as aquaculture fish and chicken fed to fish meals can be exposed to MPs and ultimately to humans. Preventive and safety measures are suggested to reduce the exposure of MPs to humans. In addition, several policy strategies are recommended to reduce the impacts of plastic waste and plastic pollution on the environment, aquatic biota, wildlife, seafood and human health.

Characterization of microplastics in digestive tract of commercial fish species from the Oman Sea

Microplastics (MPs) content of the digestive tract of two commercial fish from the northern shores of the Oman Sea were investigated. The MPs were characterized by optical microscopy, fluorescent microscopy, and SEM-EDX for their number, shape, size, and color. Polymer composition was analyzes using micro-Raman spectroscopy (RMS). MPs were recovered in all fish samples (100 %), with an average of 43.16 ± 8.23 items/individual in Otolithes ruber, and 29.9 ± 2.73 items/individual in Acanthopagrus latus. The predominant shape of MPs in both fishes was fiber (46 %) with black, transparent, and white colors. The majority of MPs were <1000 μm (75 %), and half of the MPs were smaller than 300 μm in size. Their synthetic nature was confirmed by Nile Red staining and determination of the elemental composition of selected items. Polypropylene (PP) and polyethylene (PE) were the dominant plastic polymers in the fish digestive tracts. This study reveals abundance distribution of MPs in digestive tract of commercial marine fish. High number of ingested MPs can alarm the accumulation of MPs in the northern of Oman Sea ecosystem with anthropogenic activities and raises issues in public health.

Microplastics in stomach contents of juvenile Patagonian blennies (Eleginops maclovinus)

Microplastics are one of the major environmental issues that need to be addressed because they are starting to impact food chains and are also affecting human populations. The size, colour, form, and abundance of microplastics in young blennies of the species Eleginops maclovinus were examined in the current study. While the stomach contents of 70 % of the studied individuals contained microplastics, 95 % of them included fibres. Individual size and the largest particle size that can be eaten, which ranges between 0.09 and 1.5 mm present no statistical correlation. The quantity of particles taken in by each individual does not change with size. The most present microfibers colours were blue and red. Sampled fibres were analysed with FT-IR and no natural fibres were detected, proving the synthetic origin of the detected particles. These findings suggest that protected coastlines create conditions that favour the encounter of microplastics increasing local wildlife exposure to microplastics, raising the danger of their ingestion with potential physiological, ecological, economical and human health consequences.

Microplastics in Seabird Feces from Coastal Areas of Central Chile

Pollution from plastic waste thrown into the ocean affects all levels of the food chain. Marine species of birds are affected by plastic particles of different sizes, especially the mesoplastics (1 to 10 mm) found in their digestive tract, which mainly cause obstructions. In the case of microplastics (1.000 µm to 1 mm), their presence in the digestive tract of these species has been widely reported. We studied fecal samples of the Dominican gull (Larus dominicanus) (n = 14), Magellanic penguins (Spheniscus magellanicus) (n = 8), and Humboldt penguin (Spheniscus humboldti) (n = 1) obtained from the Wildlife Rehabilitation Center of the Biobío region, Chile. Microfibers of various colors were present in the feces of Dominican gulls and Magellanic penguins, corresponding mainly in composition to polypropylene (PP) (83%) and rayon (77%). These results demonstrate that microplastic particles occur in the coastal environments of central Chile and suggest that they are probably circulating in the food chain.

Microplastic contamination in the digestive tract of sea urchins (Echinodermata: Echinoidea) in Kepulauan Seribu, Indonesia

The accumulation of microplastics on sediment surfaces contributed to the digestive tract of sea urchins contamination during foraging. Therefore, the aim of this study was to investigate the potential relationship between the accumulation of microplastics on sediment surfaces and the contamination of sea urchins' digestive tracts during their foraging activities. Sediment and sea urchins' samples were collected from Pari and Harapan Islands, in Kepulauan Seribu, DKI Jakarta, Indonesia. Microplastics were extracted and observed in sediment and the digestive tract of sea urchins' samples. Fourier transform infrared (FTIR) spectroscopy identified microplastic polymers. The average microplastic concentration on Pari Island was 160 ± 158.75 particles/kg dry weight sediment and 3.93 ± 2.25 particles/g dry weight in the digestive tract of sea urchins. Correspondingly, on Harapan Island, the values were 113 ± 41.63 particles/kg dry weight and 0.27 ± 0.28 particles/g dry weight. Fragment-type microplastics (75%) were predominantly detected in the digestive tract of sea urchins, while fiber-type microplastics (59%) were more common in sediments on Pari Island. Conversely, on Harapan Island fragment types were more prevalent (53%). Microplastics larger than 1000 µm were identified in both sediment and the digestive tract of sea urchins. The observed plastic polymers, such as polyethylene, polyester, and polypropylene were dominant at both study sites. This study postulated that microplastics in sediments may be ingested during sea urchins digestion, supported by a significant correlation of 0.016. Consequently, the presence of microplastics in sea urchins from Pari Island and Harapan Island in Kepulauan Seribu was confirmed. Future investigations should explore the toxic effects of absorbed microplastics on sea urchins' physiology, requiring further analysis.

High microplastics concentration in liver is negatively associated with condition factor in the Benguela hake Merluccius polli

Microplastics (MPs) affect both marine and terrestrial biota worldwide for their harmful effects, which range from physical cell damage to physiological deterioration. In this research, microplastics were quantified from gills, liver and muscle of demersal Benguela hakes Merluccius polli (n = 94), caught by commercial trawling from northwest African waters. Plastic polymers were identified using Fourier Transformed-infraRed spectroscopy (FT-iR). Fulton's k condition factor and the degree of DNA degradation in liver were measured. None of the individuals were free of MPs, whose concentration ranged from 0.18 particles/g in muscle to 0.6 in liver. Four hazardous polymers were identified: 2-ethoxyethylmethacrylate, polyester, polyethylene terephthalate, and poly-acrylics. MP concentration in liver was correlated negatively with the condition factor, suggesting physiological damage. Positive association of MP concentration and liver DNA degradation was explained from cell breakage during trawl hauls during decompression, suggesting an additional way of MPs harm in organisms inhabiting at great depth. This is the first report of potential MPs-driven damage in this species; more studies are recommended to understand the impact of MP pollution on demersal species.

Impact of Fibrous Microplastic Pollution on Commercial Seafood and Consumer Health: A Review

The omnipresence of microfibers in marine environments has raised concerns about their availability to aquatic biota, including commercial fish species. Due to their tiny size and wide distribution, microfibers may be ingested by wild-captured pelagic or benthic fish and farmed species. Humans are exposed via seafood consumption. Despite the fact that research on the impact of microfibers on marine biota is increasing, knowledge on their role in food security and safety is limited. The present review aims to examine the current knowledge about microfiber contamination in commercially relevant fish species, their impact on the marine food chain, and their probable threat to consumer health. The available information suggests that among the marine biota, edible species are also contaminated, but there is an urgent need to standardize data collection methods to assess the extent of microfiber occurrence in seafood. In this context, natural microfibers should also be investigated. A multidisciplinary approach to the microfiber issue that recognizes the interrelationship and connection of environmental health with that of animals and humans should be used, leading to the application of strategies to reduce microfiber pollution through the control of the sources and the development of remediation technologies.

Investigating the impacts of biofouled marine plastic debris on the olfactory behaviour of juvenile yellowtail kingfish (Seriola lalandi)

Marine microplastics are rapidly colonised by a microbial community which form a biofilm unique from the surrounding seawater that often contains infochemical-producing species associated with food sources. Here, we investigated whether juvenile kingfish (Seriola lalandi) were more attracted to biofouled plastics compared to clean plastics. Plastics were exposed to unfiltered seawater for one month to cultivate a microbial community. An olfactory behavioural experiment showed little difference in their response to the biofilm compared to clean plastic and control treatment. Further, ingestion experiments demonstrated that S. lalandi ingested fewer biofouled microplastics compared to clean microplastics. However, this was likely due to the bioavailability of the biofouled microplastics. This study highlights that while juvenile kingfish will ingest microplastics, they are not more attracted to those with a naturally acquired biofilm.

Microplastics in carnivorous fish species, water and sediments of a coastal urban lagoon in Nigeria

Plastic marine debris is a common source of pollution. Recent research has shown that plastic debris has a negative impact on marine organisms and the environment. For the first time, we investigated the presence of microplastics (MPs) in the Nigerian Lagos Lagoon ecosystem water, sediment, and the most important fish species (Hepsetus odoe, Chrysichthys nigrodigitatus, Oreochromis niloticus, and Lachnolaimus maximus). MPs were found in water, sediment, and three carnivorous fish species (H. odoe, C. nigrodigitatus, and L. maximus), except for herbivorous O. niloticus, raising concerns about the health of the Nigerian Lagos Lagoon ecosystem and the human food chain. Across the lagoon, fibres were more concentrated in the water, while fragments predominated in the sediment. Plastic debris from recreational, industrial, and domestic wastes contributed significantly to this contamination. Given the potential dangers of MPs to human health, it is critical to protect the ecosystem and its inhabitants in the Lagoon from plastic pollution. Our findings highlight the need for urgent measures to protect Nigeria's fragile coastal and marine ecosystems.

Tropical sharks feasting on and swimming through microplastics: First evidence from Malaysia

Plastic can be degraded into microplastic (<5 mm) and has been polluting worldwide marine environment and negatively impact human health. Microplastics in marine organisms are still understudied in Malaysia, let alone from a subclass Elasmobranchii. Five tropical shark species (Carcharhinus dussumieri, Carcharhinus sorrah, Chiloscyllium hasseltii, Chiloscyllium punctatum, and Scoliodon laticaudus) were examined for the presence of microplastics. 74 sharks were sampled from the local wet market and 100 % of samples contained microplastics. A total of 2211 plastic particles were found in gastrointestinal tracts (GIT) and gills, where 29.88 ± 2.34 particles per shark (mean ± SEM). Black (40.07 %) and fiber (84.44 %) microplastics were the most dominant. Extracted microplastic sizes ranged from 0.007 mm to 4.992 mm. This study suggests that microplastic uptake is gender-related for some shark species. A subsample of microplastics (10 %) was used for polymer type identification, where polyester was recorded the highest (43.95 %).

First assessment of debris pollution in the gastrointestinal content of juvenile Magellanic penguins (Spheniscus magellanicus) stranded on the west south Atlantic coasts

This paper provides the first evidence of debris pollution, including plastic, in juvenile Magellanic penguins (Spheniscus magellanicus) found stranded on the Atlantic coast of southern Buenos Aires Province, Argentina. Macro-, meso- and microparticles of anthropogenic origin were observed in 100 % of the studied birds, with debris abundance ranging between 33 and 200 items/bird. Microparticles represented 91 % of the total debris and 97 % of them were fibers. Black particles were the most abundant (30 %), followed by transparent (26 %), blue (14 %), yellow (10.3 %), and red (10 %). Infrared and Raman spectroscopy identified 62.7 % of the total particles as plastics, with polypropylene (27.8 %) and polyester (21.6 %) being the most abundant polymers. Semi-synthetic cellulosic fibers, metallic particles, and pigments were also found. The presence of metallic microparticles was suggested for the first time in penguins. Stranded juvenile Magellanic penguins are proposed as promising bioindicators of plastic pollution in the South Atlantic.

Personal protective equipment (PPE) disposal during COVID-19: An emerging source of microplastic and microfiber pollution in the environment

Waste generated by healthcare facilities during the COVID-19 pandemic has become a new source of pollution, particularly with the widespread use of single-use personal protective equipment (PPE). Releasing microplastics (MPs) and microfibers (MFs) from discarded PPE becomes an emerging threat to environmental sustainability. MPs/MFs have recently been reported in a variety of aquatic and terrestrial ecosystems, including water, deep-sea sediments, air, and soil. As COVID-19 spreads, the use of plastic-made PPE in healthcare facilities has increased significantly worldwide, resulting in massive amounts of plastic waste entering the terrestrial and marine environments. High loads of MPs/MFs emitted into the environment due to excessive PPE consumption are easily consumed by aquatic organisms, disrupting the food chain, and potentially causing chronic health problems in humans. Thus, proper management of PPE waste is critical for ensuring a post-COVID sustainable environment, which has recently attracted the attention of the scientific community. The current study aims to review the global consumption and sustainable management of discarded PPE in the context of COVID-19. The severe impacts of PPE-emitted MPs/MFs on human health and other environmental segments are briefly addressed. Despite extensive research progress in the area, many questions about MP/MF contamination in the context of COVID-19 remain unanswered. Therefore, in response to the post-COVID environmental remediation concerns, future research directions and recommendations are highlighted considering the current MP/MF research progress from COVID-related PPE waste.

Marine debris and associated organic pollutants in surface waters of Chiloé in the Northern Chilean Patagonia (42°-44°S)

We report the occurrence of plastics and associated persistent organic pollutants (POPs) in surface waters from Northern Chilean Patagonia. A total of 200 particles were found during the conducted survey. The highest number of particles found was 0.6 item m^-3. We found that 53 % of the collected particles corresponded to plastic, with an average of 0.19 ± 0.18 item m^-3. Microplastics (68 %) were the dominant size found in the area, followed by macroplastics (18 %) and mesoplastics (14 %). Most plastic particles were white (55 %) while others were <10 % each. Black and light blue represented 9 %; red, dark blue, and other colors 7 %; and green 6 %. Fragments were the most frequent shape of plastic debris (38 %), followed by Styrofoam (30 %) and fiber (27 %). Higher PBDE levels were found in the central zone, and those were higher than DDT, PeCB, HCB, and PCB levels. This study is the first report on POP occurrence in marine plastic debris from Chiloé Sea in the Northern Chilean Patagonia.

Characterization and implication of microplastics on riverine population of the River Ravi, Lahore, Pakistan

Microplastic (MP) pollution in the aquatic environment is an emerging subject worldwide. So far, very few investigations have been reported on the riverine fish population. This study investigated the implications of microplastics for three freshwater fish species (Labeo rohita, Cirrihinus mrigala, and Sperata seenghala) as bioindicators of this pollution. Raman spectroscopy was used to confirm MP polymer type and their distribution in water, sediments, and in different organs (gut, gills, liver, and muscles) of Labeo rohita, Cirrihinus mrigala, and Sperata seenghala collected from River Ravi at two sites (site I, Dhand Nano Dogar and site II, Jhamra). These selected sites were situated predominantly near agricultural lands and received polluted water from nearby sewerage and industries that represented potential sources of microplastic pollution. Histological analysis was combined with Raman spectroscopy to assess the effects of MPs on fish organs. MPs were identified in water and sediment samples with an average load (per 0.5 L or per 0.5 kg) of 33 items and 64 items for water and sediments at site I and 27 items and 19 items at site II, respectively. Of total MPs identified, 56.9% were found in bottom feeder C. mrigala, 37.91% in column feeder L. rohita, and 5.21% in S. seenghala at site I while at site II 60% were found in C. mrigala, 29% in L. rohita and 10.34% in S. seenghala. This was linked with more plastic accumulation in sediments from the nearby residential sewerage and industrial effluent flow. In this study, the identified MPs polymers were in the order of polyvinyl chloride (PVC) > polystyrene (PS) > propylene (PP) > polyethylene (PE). Among plastic shapes, fiber (58%) was the dominant plastic in water followed by fragment (21%), sheet (12%), and cube (9%). In sediment, the fragment was the common plastic shape with 51% followed by fiber (28%), sheet (19%), and cube (2%). Fragments (62.9%) in water and fibers (68.4%) in sediments were abundant at site 2. Microplastic mean occurrence in organs was in the order of gut > gills > muscles > liver at both sites. Significant histological alterations were observed in all three species including intestinal edema, hyperplasia, hepatocyte infiltration, accumulation of lipid droplets in the liver, lamellar fusion and breakage in gills, and muscle fiber necrosis. This study showed MP occurrence in the selected freshwater fishes, so further research is needed to assess plastic pollution in the riverine fish population of Pakistan. This study appeared to be the first in the selected area, as no significant information regarding plastic pollution in that riverine system was found when this study was conducted.

A short review on the recent method development for extraction and identification of microplastics in mussels and fish, two major groups of seafood

The prevalence of microplastics in the marine environment poses potential health risks to humans through seafood consumption. Relevant data are available but the diverse analytical approaches adopted to characterise microplastics have hampered data comparison among studies. Here, the techniques for extraction and identification of microplastics are summarised among studies of marine mussels and fish, two major groups of seafood. Among the reviewed papers published in 2018-2021, the most common practice to extract microplastics was through tissue digestion in alkaline chemicals (46 % for mussels, 56 % for fish) and oxidative chemicals (28 % for mussels, 12 % for fish). High-density solutions such as sodium chloride could be used to isolate microplastics from other undigested residues by flotation. Polymer analysis of microplastics was mainly carried out with Fourier-transform infrared (FTIR) spectroscopy (58 % for both mussels and fish) and Raman spectroscopy (14 % for mussels, 8 % for fish). Among these methods, we recommend alkaline digestion for microplastic extraction, and the automated mapping approach of FTIR or Raman spectroscopy for microplastic identification. Overall, this study highlights the need for a standard protocol for characterising microplastics in seafood samples.

Identification and quantification of potential microplastics in shellfish harvested in Sardinia (Italy) by using transillumination stereomicroscopy

Plastics are non-biodegradable polymers made up of different groups of petrochemical materials. Several biotic and abiotic factors can change the density of plastic fragmenting it and originating microplastics (MPs). MPs have been defined as small pieces of plastic less than 5 mm in size. Due to their small size, they are an emerging concern in the marine environment since they can be ingested by aquatic organisms, especially filter-feeding organisms, such as bivalve mollusks. Impacts of MPs exposure have been shown at various levels of biological organization, from cellular to tissue to individual and population levels. For example, oxidative stress and inflammation have been observed in copepods and mussels, obstruction and physical damage of the digestive tract were found in fish and swimming behavior alterations, disruption of foraging and feeding behavior and overall reduced fitness and survival were observed in fish and oysters. In addition, MPs can act as a vector for the transfer of chemicals to marine biota. The aim of the present study was the identification and quantification of potential MPs in shellfish harvested in Sardinia (Italy) by using transillumination stereomicroscopy. Bivalves were collected from 4 of the main production areas located along the Sardinian coast and selected according to the principles of the risk assessment. The results of the present study demonstrated the presence of potential MPs in 70% of the analyzed samples: the presence of MPs in bivalve mollusks may pose a threat to food safety, and there is an urgent need to evaluate the potential risks of MPs to human health.

Hazard index of microplastics contamination in various fishes collected off Parangipettai, Southeast coast of India

The authors of the present research aimed to assess microplastics (MPs) contamination in the gills and gut of selected fishes from various aquatic zones and also to bring out the risks of the identified polymers. Accordingly, about 200 fish specimens of 10 different species were collected from the landing center at Parangipettai, southeast coast of India. The fishes were dissected to investigate MPs contamination in their gills and gut. The dissected tissues were acid digested and filtered to observe its microplastic contamination using a stereozoom microscope. In gills, Cynoglossus arel had the least contamination (0.4 ± 0.01 particles/ind) and Mugil cephalus had highest microplastic contamination (1.7 ± 0.01 particles/ind). In gut, C. arel had the minimum contamination (0.7 ± 0.09 particles/ind) and Rastrelliger kanagurta had maximum contamination (2.3 ± 0.26 particles/ind). The size of microplastics isolated from the present study ranged from 100 to 1000 μm. Among microplastic shapes, fibers (97%) and pellets (3%) were observed. About eight colours of microplastics were observed in the fishes among which black was dominant. Three polymers such as LDPE, PP and PS were identified by μFTIR, among which LDPE (57%) was dominant. Polymer Hazard Index denotes that LDPE (6.27), PP (3.4) and PS (2.7) have a PHI score of 1-10 classifying them in the hazard category II which has a medium risk. These polymers may directly enter the human body when consumed and cause health implications which require further investigation.

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

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

Associations between bacterial communities and microplastics from surface seawater of the Northern Patagonian area of Chile

The presence of microplastics in oceans and coastlines has increased during recent years due anthropogenic activities and represents a serious environmental problem. The establishment and assembly of microbial communities in these microplastics, specifically located near aquaculture activities, is not well understood. In this study, we analyzed unique and core members of bacterial communities attached to microplastics collected from three coastal environments of the South Pacific, which represent low, medium and high anthropogenic activity derived from the aquaculture industry. Microplastics were analyzed with Fourier-transform infrared spectroscopy, scanning electron microscopy, and next-generation sequencing to assess the prevailing microplastics types, and to characterize microbial communities attached to them. We identified four main types of microplastics (polypropylene, polyethylene, nylon and polystyrene) and 3102 Operational Taxonomic Units (OTUs) at the sampled sites, which were dominated by the phylum Cyanobacteria, Bacteroidetes and Proteobacteria (mainly Alpha and Gammaproteobacteria). Similarity index analysis showed that bacterial communities in microplastics differed from those found in the surrounding seawaters, and also that they varied among locations, suggesting a role of the environment and level of anthropogenic activities on the plastisphere taxa. Despite this difference, 222 bacterial OTUs were shared among the three sites representing between 34 and 51% of OTUs of each sampled site, and thus constituted a core microbiome of microplastics. Comparison of the core microbiome with bacterial communities of the surrounding seawater suggested that the plastisphere constituted a selective habitat for diverse microbial communities. Computational predictions also provided evidence of significantly enriched functions in the core microbiome. Co-occurrence networks revealed that putative ecological interactions among microplastics OTUs was dominated by positive correlations. To the best of our knowledge, this is the first study that evaluated the composition of microbial communities found in microplastics from the Patagonia region of the Southern Pacific Ocean.

Effect of land use on microplastic pollution in a major boundary waterway: The Arvand River

The occurrence of microplastics (MPs) was investigated in the Arvand River (Iran). The Arvand River (200 Km) is a major water body that flows through land with diverse use and it meets the Persian Gulf. This study constitutes the first assessment of MP pollution (prevalence and physico-chemical characteristics) in the Arvand river, both in the sediment and in the water. MP monitoring has been carried out in 24 stations located along the river. The MP pollution found ranged between 1 and 291 items·L^-1 and 70 to 15,620 items·kg^-1 (dw), in water and sediment, respectively. The majority of MPs were fibres, black/grey and yellow/orange in colour, and mainly 250-500 μm and >1000 μm in size. Polyethylene terephthalate (PET), polypropylene (PP), nylon (NYL), high-density polyethylene (HDPE), and polystyrene (PS) were found in sediment samples. All these polymers, except HDPE, were also identified in the water samples. PET and PP were dominant in the water samples; whereas PET and PS were the most abundant in the sediments. The vicinity of urban wastewater effluents could be behind MP pollution in both water and sediments. Significant differences (p < 0.05) of MP concentrations were affected by different land uses when comparing MP levels in undisturbed natural area with urban areas. A strong correlation between MP fibres and fragments found with PCA biplots revealed their similar distribution in water. In the sediment samples, fibre and fragment MP particles were significantly correlated with colloidal particles (e.g., clay and organic matter) suggesting a relevant role of colloidal particles in the aquatic ecosystem of the Arvand River in transporting MPs. This study contributes to the better understanding of the presence of MP in major rivers, which are systems that have been scarcely investigated for this type of pollution, and it can inform interventions to reduce MP inputs to the river and sea.

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

A literature review was carried out to analyze the current status of microplastic research in Latin America and the Caribbean (LAC). Specifically, this work focused on publications pertaining to (1) occurrence and distribution of microplastics in the environment, including water, sediments, and soil and (2) the environmental impact of MPs, particularly their presence and effects on aquatic and terrestrial organisms. The review included peer-reviewed articles from Scopus, Science Direct, Web of Science, Google Scholar and two iberoamerican open access databases (Redalyc and SciELO). It was found that LAC has only contributed to 5% of the global scientific output on microplastics, and overall the highest contributor within the region was Brazil (52%), followed by Chile (16%) and Mexico (13%). An additional section analyzing the barriers to conducting microplastic research in LAC and their exacerbation by the current COVID-19 pandemic was included to provide additional context behind the relatively low scientific production and improve recommendations encouraging research in this region.

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

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

Occurrence of microplastics (MPs) in the gastrointestinal tract of fishes: A global systematic review and meta-analysis and meta-regression

The presence of Microplastics (MPs) in food has become a global health concern in the last two decades. In this study, an attempt was made to obtain articles about the occurrence of MPs in the gastrointestinal tract (gt) of fishes using searching the Scopus and PubMed databases from 1 January 1990 to 10 August 2021. The occurrence of MPs was meta-analyzed using the random effect model (REM). The results indicate that pooled occurrence of MPs in gastrointestinal of fishes was 2.76 P/gt: 95%CI:2.65-2.86 P/gt. Occurrence MPs in gastrointestinal of fishes in closed water sources (5.86 P/gt) was higher than free water sources (2.46 P/gt). In addition, the rank order of water sources based on occurrence MPs in gastrointestinal of fish was Lake (5.50 P/gt) > Estuary (5.46 P/gt) > River (2.91 P/gt) > Bay (2.85 P/gt) > Sea (2.58 P/gt) > Ocean (1.29 P/gt). The lowest and highest occurrence MPs in gastrointestinal of fishes were observed in high-income economies (1.45 P/gt) and low-income economies (8.08 P/gt), respectively. The higher frequency of color in MPS was related to blue with polyethylene-type polymers. Therefore, control plans to reduce the occurrence of MPs in fishes is recommended.

Microplastics in fish meals: An exposure route for aquaculture animals

Microplastics (MPs) are widely detected in many marine fishes. Fish meal contaminated by MP may constitute a potential threat to aquaculture animals. This study analyzed the characteristics of MP in fish meals from ten major fish meal-producing countries around the world. Microplastics were isolated from fish meal, examined under a microscope and identified using Fourier transform infrared microspectroscopy (μ-FT-IR). The results showed that MP pollution was widely detected in fish meal samples from ten countries. The average MP abundance of fish meals was 5.5 ± 1.6 items/g, with higher levels in China, Peru and Myanmar, which might be related to the high pollution level in fish and their habitats. In isolated MPs, fibers were the main shape type, and the most common size was 500-1000 μm. A total of 6 polymers were identified, with cellophane (CP), polypropylene (PP) and polyethylene teraphalate (PET) being the most common types. The total amount of MP ingestion from fish meals by different cultured animals was also estimated, with Atlantic salmon Salmon salar ingesting the largest number of MPs (9361 items), and red swamp crayfish Procambarus clarkii ingesting the smallest number of MPs (19 items). Thus, fish meal constitutes an important exposure route of MPs for aquaculture animals. The results of this study will provide a basis to assess the potential health risks of MPs in fish meals around the world.

Microplastic pollution in coastal ecosystem off Mumbai coast, India

Microplastics (MPs) are anthropogenic pollutants which can adsorb toxic substances from surrounding water and absorb into the fish body. During the present study, MPs were observed in water, sediment, and gastrointestinal tracts of marine biota samples collected from the coastal waters of Mumbai, India. The mean abundances of MPs recorded in water samples 372 ± 143 items/liter and 9630 ± 2947 items/kg dry weight (DW) in sediment samples. The mean abundance of MPs in pelagic fish species varied from 6.74 ± 2.74 to 9.12 ± 3.57 items/individual and in the demersal species the values ranged from 5.62 ± 2.27 to 6.6 ± 2.98 items/individual. Shape-wise, four type of MPs were observed in the surface waters, sediments and all studied species, predominantly fibers, followed by fragments, pellets/beads, and films. Seven different colors of MPs (red, blue, black, translucent, brown, green, and yellow) were observed from studied samples. MPs of size below 250 μm formed the dominant size in the surface water, sediments, and biota samples except Bombay duck and Malabar sole fish. Based on Raman spectroscopy analysis, eleven types of plastic polymers identified from all studied samples. Thus, presence of MPs in studied biota indicates the transfer of MPs through interlinked food chain/web to higher trophic levels and the occurrence of MPs in the fish gut underlines the necessity of more studies on processing interventions for reducing the microplastic contamination in fish for human consumption.

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

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

Microplastic contamination of fish gills and the assessment of both quality assurance and quality control during laboratory analyses

Microplastic pollution has received substantial international attention in terrestrial and marine environments and in the atmosphere. In this study, we assessed microplastic pollution and analyzed the accumulation of microplastics in the gills of fish caught in the Zhoushan fishing ground from September 2017 to March 2018. The average abundance of microplastics was 0.49 ± 0.54 particles/gill and frequently found chemical polymers was polyethylene terephthalate. We also conducted experiments on microplastic pollution in the water and the working solutions used during the analytical process and found that the source of microplastic contamination was the solutions used. Moreover, we evaluated and scored experimental quality control and quality assurance adapted from the 'Total Accumulated Score' method. Valuable steps are recommended in order to produce reliable results and improve the quality of results in microplastic analyses.

Occurrence and exposure analysis of microplastic in the gut and muscle tissue of riverine fish in Kermanshah province of Iran

This study aimed to determine the presence of MPs in the gut and muscle tissue of riverine fish collected from the Qarasu River, Kermanshah, Iran. The results highlighted that MPs were found in the gut and muscle of all fish species at an average abundance of 8.12 ± 4.26 P/individual and 0.85 ± 0.38 P/g muscles, respectively. High amounts of MPs were found in the range of 1-25 μm in terms of size distribution. The properties of MPs extracted indicated that PE, PP, PS, and PA in the monotype of fiber and fragment were the most abundant plastic types and shapes found. Additionally, EAI was calculated for MPs found in the muscle. So, 174.43 and 127.19 P/kg/bw/year (1.28 and 0.93 g/kg/bw/year), were intake by two groups of adults and children, respectively. These findings highlight the contamination of fish as a common source of marine food in home consumption and the probability of entrance into the human diet.

Presence and Characterization of Microplastics in Coastal Fish around the Eastern Coast of Thailand

Marine microplastic has been in the limelight recently. This study aimed to describe microplastic types ingested by 274 fish from Thailand’s eastern coast in 2020 and to compare the microplastic content among different feeding traits. The microplastics in the gastrointestinal tracts and gills were extracted, analyzed, and identified using FT-IR spectroscopy. Approximately 13.14% of the total specimen ingested microplastics, with an average of 0.14 items per individual. The detection frequency of microplastics was relatively high compared with other regions in Thailand but relatively low compared to global standards. Of the microplastic contaminated specimens, 56.41% had at least one piece of microplastic in their gastrointestinal tract. Pelagic (14.47%) species were found to have ingested more microplastics than the demersal (12.63%) group. Dominant aspects found included PET (as in polymers), fiber (as in shape), and black (as in color). However, microplastic numbers fluctuated with the size, weight, and feeding behavior of fish. This result suggested that the pelagic has a higher exposure risk and microplastic ingestion in relatively small quantities in a range of fish species. Our results indicated that the occurrence of microplastics in fish is not influenced by organism habitat or trophic level, although the characteristics of pelagic fish might significantly increase the chance of exposure to microplastics in pelagic species.

Occurrence of perfluoroalkyl substances (PFASs) in marine plastic litter from coastal areas of Central Chile

Perfluorinated alkyl substances (PFASs) were determined in marine plastic litter (MPL) on six beaches of central Chile. MPL was characterized physically and chemically, showing an abundance of macroplastic (size >2.5 cm). The polypropylene (PP) (47%) was the predominant polymer found. The Desembocadura beach, located at the mouth of the Biobio River, recorded the highest abundance of MPL (3.7 items m^-2). PFAS detected (n = 15/21) ranged from 279 to 1211 pg g^-1 and accounted for MeFOSE (46%) > PFHxS (14%) > PFPA (11%) > PFBS (6%) > PFOA (4%) and > PFOS (4%). Long-chain PFAS were prevalent, which can be metabolically degraded into PFOS (new POPs). This study i) highlights the need to further investigate the occurrence of chemicals in the MPL to reduce their impact on the environment; and ii) points out the need to improve future coastal management strategies for the elimination of solid waste along the coast of the country.

Hyperspectral Imaging as a Potential Online Detection Method of Microplastics

Microplastic pollution in aquatic environment has raised concern and as a result a number of studies have recently been published to find solutions for its rapid increase. Different methods have been proposed for microplastic identification. Spectral imaging shows a lot of promise for polymer identification; however, the identification time needs to be improved. Hyperspectral imaging (HSI) combined with chemometric analysis can reduce the identification times. In this study, we provide a review of recent studies related to polymer identification using HSI with a focus on the adopted classification algorithm and its factors for the online implementation of HSI. Furthermore, we review the limit of detection by HSI and the effect of particle size on classification accuracy. Additionally, performance of this method for various types of samples is also discussed. We conclude that HSI is possible to be a fast alternative for online microplastic detection.

Direct ingestion, trophic transfer, and physiological effects of microplastics in the early life stages of Centropristis striata, a commercially and recreationally valuable fishery species

Microplastics are ubiquitous in marine and estuarine ecosystems, and thus there is increasing concern regarding exposure and potential effects in commercial species. To address this knowledge gap, we investigated the effects of microplastics on larval and early juvenile life stages of the Black Sea Bass (Centropristis striata), a North American fishery. Larvae (13-14 days post hatch, dph) were exposed to 1.0 × 10⁴, 1.0 × 10⁵, and 1.0 × 10⁶ particles L^-1 of low-density polyethylene (LDPE) microspheres (10-20 μm) directly in seawater and via trophic transfer from microzooplankton prey (tintinnid ciliates, Favella spp.). We also compared the ingestion of virgin and chemically-treated microspheres incubated with either phenanthrene, a polycyclic aromatic hydrocarbon, or 2,4-di-tert-butylphenol (2,4-DTBP), a plastic additive. Larval fish did not discriminate between virgin or chemically-treated microspheres. However, larvae did ingest higher numbers of microspheres through ingestion of microzooplankton prey than directly from the seawater. Early juveniles (50-60 dph) were directly exposed to the virgin and chemically-treated LDPE microspheres, as well as virgin LDPE microfibers for 96 h to determine physiological effects (i.e., oxygen consumption and immune response). There was a significant positive relationship between oxygen consumption and increasing microfiber concentration, as well as a significant negative relationship between immune response and increasing virgin microsphere concentration. This first assessment of microplastic pollution effects in the early life stages of a commercial finfish species demonstrates that trophic transfer from microzooplankton can be a significant route of microplastic exposure to larval stages of C. striata, and that multi-day exposure to some microplastics in early juveniles can result in physiological stress.

Incidence of microplastics in gastrointestinal tract of golden anchovy (Coilia dussumieri) from north east coast of Arabian Sea: The ecological perspective

Anthropogenic marine litters or microplastics (MPs) accumulation in marine organisms is an emerging environmental threat. In this background, the gastrointestinal tract of Coilia dussumieri (n = 150) was studied in the samples collected from the fishing grounds of the north east coast of Arabian Sea through experimental fishing. Out of the total 150 specimens collected, all showed the incidence of microplastic particulates in the guts. The average abundance of MPs was found to be 6.98 ± 2.73 items/individual whereas gastrointestinal tract recorded with an average number of 28.84 ± 10.13 MPs/g in the gut material. The dominant MPs were found in the size range of 100-250 μm and of fibers type mostly blue in color. The prevalence of MPs in Coilia dussumieri is a matter of serious concern due to its ecological consequences due to trophic transfer in the connected food chains and probable threats to the health of human beings consuming the fish.

Microplastic fibers in the gut of highly consumed fish species from the southern Caspian Sea

This study assesses the frequency, distribution, characteristics, and chemical composition of microplastics (MPs) in the gut of highly consumed fish species, namely leaping mullet (Chelon saliens), common carp (Cyprinus carpioi), and Caspian kutum (Rutilus caspicus), in the southern Caspian Sea biome. Fibers are found to be the only shape of MPs. Black MPs and polystyrene, polypropylene, and polyethylene terephthalate polymers are dominant. MP frequency is highest in leaping mullet's gut, while kutum specimens exhibited the lowest MP frequency, reflecting that leaping mullet is a neritic species and thus highly exposed to MP influx in shallow coastal water, while the other species are benthopelagic. The estimated condition index reflected a significant difference between the species, implying that MPs may pose adverse health impacts on leaping mullet and common carp, with no undesirable effect on Caspian kutum. No significant relationship exists between biological parameters and the MP frequency in the fish gut.

Development of a fast and efficient method to analyze microplastics in planktonic samples

Microplastics (MPs) affect plankton (a basis of the trophic chain) and planktivorous fish can ingest them through food confusion or by trophic transmission. Consensus to determine MPs in plankton is lacking and, so, three digestion treatments were evaluated: Alkaline (potassium hydroxide) and enzymatic (protease plus lipase) digestions, both combined with a hydrogen peroxide stage; and an oxidative method using a surfactant (sodium dodecyl sulfate) plus hydrogen peroxide. The alkaline method using potassium hydroxide was found to damage polystyrene. MPs were identified with a stereomicroscope and characterized by reflectance infrared microscopy in semi-automatic mode (using dedicated multi-well aluminium plates). Analytical recoveries for polypropylene, polystyrene, polyethylene, polyamide, polyvinyl chloride and polyethylene terephthalate were higher than 75%, 82% and 83% for the alkaline, enzymatic and oxidative treatments, respectively. The enzymatic method was successfully validated in a European interlaboratory exercise and the oxidative method was demonstrated to be a reliable, fast and cheaper alternative.

Development of robust models for rapid classification of microplastic polymer types based on near infrared hyperspectral images

Hyperspectral data in the near infrared range were examined for nine common types of plastic particles of 1 mm and 100-500 μm sizes on dry and wet glass fiber filters. Weaker peak intensities were detected for small particles compared to large particles, and the reflectances were weaker at longer wavelengths when the particles were measured on a wet filter. These phenomena are explainable due to the effect of the correlation between the particle size and the absorption of infrared light by water. We constructed robust classification models that are capable of classifying polymer types, regardless of particle size or filter conditions (wet vs. dry), based on hyperspectral data for small particles measured on wet filters. Using the models, we also successfully classified the polymer type of polystyrene beads covered with microalgae, which simulates the natural conditions of microplastics in the ocean. This study suggests that hyperspectral imaging techniques with appropriate classification models allow the identification of microplastics without the time- and labor-consuming procedures of drying samples and removing biofilms, thus enabling more rapid analyses.

Plastic ingestion by fish in the coastal waters of the Hengchun Peninsula, Taiwan: Associated with human activity but no evidence of biomagnification

Plastic pollution has become a global threat to the marine environment. Many studies have indicated that marine creatures are at risk of plastic ingestion, but relevant studies are still lacking in Taiwan. In this study, we quantified plastic debris ingestion by marine fish in the coastal waters of the Hengchun Peninsula, including the Kenting National park, located in southern Taiwan. We also investigated possible biotic and abiotic factors associated with the quantity of ingested plastic by fish. In the 117 fish samples we examined, 94.87% of them had ingested plastic debris, and all of the observed debris was microplastics (<5 mm). The average number of ingested microplastics was 5.6 ± 5.1 pieces per fish (ranged 0-32 pieces per fish). The major type and color of microplastics were fiber (96%) and blue (43%), respectively. The quantity of ingested microplastics was not significantly different between the reef and pelagic fish. However, reef fish from the more populated west and south coast ingested more microplastics than that from the east coast, suggesting that microplastic ingestion by fish is related to human activity. Regarding biotic factors, the size, trophic level, and taxonomic family of the fish were not significantly associated with the number of ingested microplastics. Our results, the first investigation of microplastic ingestion in marine fish of Taiwan, show a high prevalence of microplastic ingestion but no biomagnification of microplastics in the fish. More research is much needed to better characterize the biological and ecological impacts of plastic debris on fish.

From plastics to microplastics and organisms

The amount of plastic waste and microplastics released into marine environments has increased rapidly in recent decades. The durability of plastic materials results in major problems following their release into the environment. This study provides an overview of recent findings on issues related to plastic degradation, the accumulation of microplastics in mussels and fishes, and the toxicological effects associated with the ingestion of microplastics. These findings confirm the serious problem of slowly degrading plastics (which rarely degrade fully) in natural marine environments. Microplastics have become widespread pollutants and have been detected in mussels and fish around the world. Microplastic particles, whether virgin or with adsorbed pollutants on their surfaces, pose a health problem after being ingested by marine organisms. This paper ends by highlighting the need for certain improvements in studies of these phenomena.

Microplastic contamination in salt pans and commercial salts - A baseline study on the salt pans of Marakkanam and Parangipettai, Tamil Nadu, India

We studied the abundance of microplastics from commercial table salts and table salts from salt pans at Marakkanam and Parangipettai, Tamil Nadu, India. Microplastic abundance in the salts collected from salt pans had a range of 3.67 ± 1.54 to 21.33 ± 1.53 nos./10 g of salt which were higher than the microplastics retrieved from the commercial salts which ranged from 4.67 ± 1.15 to 16.33 ± 1.53 nos./10 g of salt. All the microplastics retrieved were fibers which were secondary in origin. Black, red, blue, green, white, brown, and colorless microplastics were observed in the samples. FT-IR results showed that 4 types of polymers, namely, Nylon, Polypropylene (PP), Low Density Polyethylene (LDPE), and Polyethylene Terephthalate (PET) were present in the samples. Domestic and municipal wastewater discharges into the estuaries may contribute to microplastics in the table salts. Our study proves that table salts (processed and unprocessed) are prone to microplastic contamination.

A comparison of microplastic contamination in freshwater fish from natural and farmed sources

Contamination of aquatic systems mainly by urbanization and poor sanitation, deficient or lack of wastewater treatments, dumping of solid residues, and run off has led to the presence of particles, including manmade polymers, in tissues of many marine and freshwater species. In this study, the prevalence of microplastics (MPs) in freshwater fish from farmed and natural sources was investigated. Oreochromis niloticus from aquaculture farms in the Huila region in Colombia, and two local species (Prochilodus magdalenae and Pimelodus grosskopfii), naturally present in surface waters were sampled. Of the particles identified, fragments were the predominant type in the three tissue types (stomach, gill, and flesh) derived from farmed and natural fishes. MicroFT-IR spectroscopy was conducted on 208 randomly selected samples, with 22% of particles identified as MPs based on spectra with a match rate ≥ 70%. A total of 53% of identified particles corresponded to cellophane/cellulose, the most abundant particle found in all fish. Not all fish contained MPs: 44% of Oreochromis farmed fish contained MPs, while 75% of natural source fish contained MPs in any of its tissues. Overall, polyethylene terephthalate (PET), polyester (PES), and polyethylene (PE) were the prevalent MPs found in the freshwater fish. A broader variety of polymer types was observed in farmed fish. The edible flesh part of fish presented the lower prevalence of MPs compared to gill and stomach (gut), with gut displaying a higher frequency and diversity of MPs. This preliminary study suggests that the incidence and type of MPs varies in farmed verses natural fish sources as well as across different tissue types, with significantly less detected within the edible flesh tissues compared with stomach and gill tissues.

Microplastic Contamination of Seafood Intended for Human Consumption: A Systematic Review and Meta-Analysis

BACKGROUND

Microplastics (MPs) have contaminated all compartments of the marine environment including biota such as seafood; ingestion from such sources is one of the two major uptake routes identified for human exposure.

OBJECTIVES

The objectives were to conduct a systematic review and meta-analysis of the levels of MP contamination in seafood and to subsequently estimate the annual human uptake.

METHODS

MEDLINE, EMBASE, and Web of Science were searched from launch (1947, 1974, and 1900, respectively) up to October 2020 for all studies reporting MP content in seafood species. Mean, standard deviations, and ranges of MPs found were collated. Studies were appraised systematically using a bespoke risk of bias (RoB) assessment tool.

RESULTS

Fifty studies were included in the systematic review and 19 in the meta-analysis. Evidence was available on four phyla: mollusks, crustaceans, fish, and echinodermata. The majority of studies identified MP contamination in seafood and reported MP content < 1  MP / g , with 26% of studies rated as having a high RoB, mainly due to analysis or reporting weaknesses. Mollusks collected off the coasts of Asia were the most heavily contaminated, coinciding with reported trends of MP contamination in the sea. According to the statistical summary, MP content was 0 - 10.5  MPs / g in mollusks, 0.1 - 8.6  MPs / g in crustaceans, 0 - 2.9  MPs / g in fish, and 1  MP / g in echinodermata. Maximum annual human MP uptake was estimated to be close to 55,000 MP particles. Statistical, sample, and methodological heterogeneity was high.

DISCUSSION

This is the first systematic review, to our knowledge, to assess and quantify MP contamination of seafood and human uptake from its consumption, suggesting that action must be considered in order to reduce human exposure via such consumption. Further high-quality research using standardized methods is needed to cement the scientific evidence on MP contamination and human exposures. https://doi.org/10.1289/EHP7171.

Review of current trends, advances and analytical challenges for microplastics contamination in Latin America

Microplastics accumulation is an emerging environmental issue and a threat to marine life and human health. There is a growing number of investigations on the abundance and distribution of microplastics in different water bodies and biota worldwide, with relatively few studies conducted in Latin America, however, the current knowledge of microplastics sources, occurrence, transport, fate and potential impacts remains largely unexplored. This review presents the current trends and advances of microplastics on a lesser known region of the world by compiling the research performed to date in different environmental compartments. The sampling techniques and methods for microplastics extraction in the existing literature data are also summarized. Among 78 published studies reviewed, 34% of studies were from Brazil and 46% of studies have mainly focused on biota. The main findings showed that microplastics are not negligible across Latin America significantly varying in their distribution, with the prevalence of fibers comprising 62% of the total. Polyethylene, polypropylene, polyethylene terephthalate and polystyrene have been identified as the most common polymer types, accounting for 80% of the total. Limited studies and lack of standardized methodologies render difficulties to establish fundamental information on microplastics abundance and types in most countries of this region. Therefore, this review will primarily serve as a baseline when evaluating the environmental relevance of microplastics in Latin America and would stimulate discussions focusing on this topic, calling for more research in future.

Plastic density as a key factor in the presence of microplastic in the gastrointestinal tract of commercial fishes from Campeche Bay, Mexico

Microplastics (MPs) are currently one of the primary marine pollution problems around the world. MPs are distributed throughout the water column, dependent mainly on the density that is given by the polymer type, as well as the location, depth, and velocities of the water flows. This situation allows all aquatic organisms to be exposed to MPs. Furthermore, toxic substances can adhere to the MPs, making the consumption of fish with MPs a risk to human health. The aim of this study was to evaluate and characterize the microplastics present in the gastrointestinal tract of six species of fish which had the highest human consumption in Campeche, Mexico and their relationship with the density of MPs founded. A total of 316 microplastic particles from 240 individuals were found with 1.31 ± 2.59 of microplastics per fish. The results indicate that there are differences (KW-H = 53.14) between the densities of the MPs present in demersal fish (1.41 ± 0.4 g cm^-3) with respect to the pelagic species (1.04 ± 0.24 g cm^-3). Likewise, differences were found between fibers, fragments, and pellets present in the studied fish with a pelagic: demersal ratio of 1: 2.4 for all microplastics. The demersal species Haemulon plumierii (n = 40) presented the highest number of MPs with 115 items in total, 73 fibers, and 42 fragments. The results of this research show the first evidence that the density of the material from which microplastics are made play a key role determining their fate in marine fish habitats.