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

Diet characteristics of tidal creek-associated fishes of the northeastern Arabian Sea with special reference to microplastic ingestion

The present study assessed the diet characteristics, trophic guild structure, and microplastics (MPs) ingestion by a group of fish sourced from the tidal creeks of the Mumbai coast along the Eastern Arabian Sea. The diet patterns were characterized using gastro-somatic index (GaSI), relative length of gut (RGL), diet overlap (α), diet breadth (Bi), and relative abundance of food items (%IOP), with a special emphasis on MPs contamination. The findings revealed that teleost and shrimps are the most preferred food items for these species. Whereas MPs contribute 5.50% of the total diet composition of the selected fishes. Additionally, we tried to find out the influence of fish size and dietary attributes on MP ingestion, identifying trophic level as a significant factor influencing contamination levels. Using the Polymer Hazard Index (PHI), the potential risks posed by MPs in fish samples were assessed, revealing notable discrepancies among polymers. For instance, polyvinyl chloride showed the highest PHI score of 198.75 and a hazard score reaching the highest risk category (IV), indicating substantial environmental risk. In summary, our findings highlight the impact of fish diet characteristics on MPs contamination and the varying levels of MP risks along the Mumbai coast, categorized according to polymer type from low to high risk.

Performance evaluation of a hyphenated laser spectroscopy system with conventional methods for microplastic analysis

Microplastics are one of the concerning environmental pollutants because of their ubiquity. Their capability to adsorb other environmental pollutants increases the risk even further. Existing identification approaches for microplastic characterization for polymer class and their surface-adsorbed heavy metal detection require the utilization of multiple resources and expertise. The article discusses the applicability of a custom-made hyphenated Laser Induced Breakdown Spectroscopy (LIBS)-Raman spectroscopic system in characterizing microplastics by comparing the analytical performance with conventional methods such as Attenuated Total Reflectance- Fourier Transform Infrared (ATR-FTIR) spectroscopy, confocal Raman spectroscopy, and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Raman analysis identified polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) plastics, which is confirmed by confocal Raman and FTIR study of the same. LIBS study of microplastics detected heavy metals such as Al, Ni, Co, and Zn, along with Ca and Mg trace elements. The cross-examination with EDS validates these trace elements' presence on the microplastics' surface. The results of the reported LIBS-Raman analysis and its validity evaluated using conventional gold-standard methods show the applicability of the proposed methodology in characterizing microplastics from environmental resources with less or no sample preparation in short time.

The silent threat of plastics along the coastal frontiers of Bangladesh: Are we concerned enough?

Globally plastic pollution is posing a significant threat to the health and integrity of coastal ecosystems. This study aimed to provide a comprehensive overview of plastic pollution in the coastal areas of Bangladesh by examining land-based macroplastic distribution, exploring microplastic (MP) contamination in the coastal aquatic ecosystem and enhancing our understanding of the potential risks associated with MP contamination. Citizen science based monitoring approach using the android application was applied to understand the land-based plastic pollution in the coastal area of Bangladesh. From December 2022 to December 2023, a total of about 3600 photographs of plastic items from 215 citizen scientists were received from the coastal area of Bangladesh covering 580 km long coast line. Polymer Hazard Index (PHI) and Pollution Load Index (PLI) were also calculated to understand the risk of plastic pollution in sediment, water, aquatic organism, dried fish and sea salt. A total of 43 land-based plastic items reported from the coastal area of Bangladesh. Among these plastic items single use items contributed 58.2 % while disposable plastic items contributed 41.8 %. A strong spatial variability in the distribution of these plastic items was observed. PHI and PLI values suggested hazard category-I for MP contamination in sediment, sea salt, water, commercial fishery resources and dry fish. This study highlighted that coastal land area, sea salt, dried fish, water, sediment and organisms are contaminated with plastics which might have the potential threats to human health. Findings from this study will serve as reference data and also baseline for future research to combat the plastic pollution.

Atmospheric deposition of microplastics in an urban conglomerate near to the foothills of Indian Himalayas: investigating the quantity, chemical character, possible sources and transport mechanisms

The global apprehension regarding the ubiquitous presence of microplastics (MPs)and their associated health risks underscore a significant challenge. However, our understanding on the occurrence and characteristics of this emerging class of pollutants in the different environmental compartments remains limited. For instance, despite housing approximately 20-25% of the global population, the evidence of the atmospheric MPs in Indian Subcontinent is exceedingly rare. Hence, we for the first-time present data on the depositional flux, chemical composition, morphological features of the atmospheric MPs collected from the foothills of Indian Himalayas. The total number of MPs for the collected samples ranged from 65 to 752 particles, with an average of 317±171 particles count. The average flux of atmospheric MPs was 2256±1221 particles/m2/day and varied significantly from 462 particles/m2/day to 5346 particles/m2/day. The highest deposition (5346 particles/m2/day) of atmospheric MPs was recorded during the 3rd week of sampling, coinciding with the Diwali festival. Based on the visual characteristics, we determined that the size of MPs ranged from 67-2320 μm, with a predominant presence of smaller particles (<1200 μm), primarily composed of fragments and films/sheets. Raman spectroscopy indicated that the analyzed MPs were mainly composed of 4 different polymer types, including PE (46.8±7.2 %), PP (20.9±7.4 %), PS (15.6±3.8 %) and PET (16.7±9.9 %). We further highlighted the extent to which climate variables control the deposition of atmospheric MPs in this urban conglomerate located in the foothills of Himalayas. Our Lagrangian parcel tracking approach showed that the greater frequencies are of local origin and clustered near to the studied region. We also speculate that atmospheric microplastics can be transported along the westerly winds. Though we did not observe any significant relation (p>0.05, n=16) between meteorological parameters and the quantity of atmospheric MPs.

Ecological assessment of microplastic contamination in surface water and commercially important edible fishes off Kadalundi estuary, Southwest coast of India

This study focuses on the Kadalundi estuary, Kerala's first community reserve, investigating the prevalence and impacts of microplastics on both the estuarine environment and selected fish species. This study presents the initial evidence indicating the consumption of microplastic particles by 12 commercially important edible fish species inhabiting the Kadalundi estuary. Analysis revealed significant accumulations of microplastic fibers within the surface water. In examining 12 fish species from demersal and pelagic habitats, microplastics were found in both the gastrointestinal tracts and gills. In the digestive tracts, microplastic fragments constituted the highest proportion (46%), while in the gills, microplastic fibers were dominant (52.4%). This study observed a prevalence of blue microplastics over other colors in both water and fish samples. Notably, demersal species showed a higher incidence of ingested microplastics. Polymer analysis identified Polypropylene (PP), Nylon, Low-Density Polyethylene (LDPE), Polyethylene (PE), Polypropylene isotactic (iPP), PE 1 Octene copolymer, and Rayon in water samples, while fish samples predominantly contained LDPE, PP, PE, and Nylon. Risk assessment utilizing the Polymer Hazard Index (PHI) categorized certain polymers as posing minor to moderate risks. Pollution Load Index (PLI) computations indicated moderate to high levels of microplastic contamination across various sampling sites in the estuary. Principal Component Analysis (PCA) revealed a lack of correlation between fish size and microplastic ingestion, underscoring environmental factors' influence on microplastic intake. The study emphasizes the implications of microplastic pollution on the fragile ecosystem of the Kadalundi estuary, posing potential risks to biodiversity and human health.

Incidence of microplastic contamination in fishes of the Ramsar Wetland, Loktak - The world's only floating lake from the Indian Himalayan region

Microplastics are ubiquitous, and their widespread prevalence in the ecosphere has generated concerns about their potential effects on terrestrial and aquatic organisms. However, studies pertaining to ecologically sensitive freshwater ecosystems, such as Ramsar wetlands, is scarce. Therefore, the study was conducted in Loktak, the world's only floating lake, and one of the largest wetland in the Indian Himalayan region. The wetland's degradation and pollution have resulted its inclusion in the Montreux Record, underscoring the need for studying this eco-sensitive freshwater system. This work investigated the (i) abundance, morphotype and size of microplastics in fish, and (ii) chemical composition of the microplastics consumed and accumulated in the fish of Loktak lake. Fish samples representing eight species were collected and analyzed for microplastics. Results revealed that ∼91% of the sampled fish ingested microplastics. Fragment was identified as the predominant morphotype (∼82%). Plastic polymers including polyamide (PA), polystyrene (PS), polycarbonate (PC) and carboxymethyl cellulose (CMC) were detected. The occurrence of heavy metals - chlorine (Cl), palladium (Pd), sodium (Na), zinc (Zn), lead (Pb) and copper (Cu) suggests their adhesion on the microplastics. The occurrence of microplastics in fish indicates pollution in the lake and poses a potential health risks to humans through consumption. Therefore, implementing comprehensive management approaches is imperative to mitigate this emerging pollution and uphold the ecological integrity of the Ramsar site. Substantial information on microplastics and their potential human exposure through fish consumption, particularly in the Indian Himalayan region, remains to be assessed, underscoring the need for extensive study.

Microplastic contamination in salt-cured fish and commercial sea salts: an emerging food safety threat in relation to UN Sustainable Development Goals (SDGs)

Microplastic (MP) contamination in seafood, particularly processed varieties like dried and salt-cured fish, poses a significant threat to human health. This study investigated MP levels in 22 salt-cured fish species and commercial sea salts along the Indian east coast. Results showed substantially higher MP concentrations compared to global averages, with fragments and fibres (< 250 µm) composing 70% of identified MPs, primarily PVC and PS polymers (> 55%). Station 2 exhibited high pollution levels, with salt-cured fish averaging 54.06 ± 14.48 MP items/g and salt containing 23.53 ± 4.2 MP items/g, indicating a high hazard risk index. A modest correlation was observed between MP abundance, morphotypes, polymer composition in the salt, and their impact on fish products. Given the critical link between food safety, security, and public health, further research is imperative to mitigate MP contamination, aligning with UN Sustainable Development Goals (Goal 2, Goal 3, Goal 14, and Goal 15) for enhanced food safety and security.

Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively.

Microplastic pollution in high-altitude Nainital lake, Uttarakhand, India

Microplastics (MPs) contamination has been reported in all environmental compartments, but very limited information is available at higher-altitude lakes. Nainital Lake, located at a high altitude in the Indian Himalayas, has various ecosystem services and is the major source of water for Nainital town, but the MP abundance is still unknown. This study presents the first evidence of the abundance and distribution of MP in Nainital Lake. Surface water and sediment samples were analysed from 16 different sites in and around the catchment area of Nainital Lake. The MP were observed in all the samples, and their abundance in surface water was 8.6-56.0 particles L-1 in the lake and 2.4-88.0 particles L-1 in hotspot sites. In the surface sediment, MP abundance ranged from 0.4-10.6 particles g-1, while in the hotspot sediment, the mean abundance was 0.6 ± 0.5 particles g-1. Fibers were the dominant MP, while 0.02-1 mm were the predominant size of MP particles. The results of chemical characterization showed the presence of six polymers, among which high-density polyethylene was the most abundant. The Polymer Hazard Index assessment classified the identified polymers as low-to high-risk categories, with a higher abundance of low- (polypropylene) and medium- (polyethylene)-risk polymers. Tourist activities and run-off catchments can be considered the major sources of MP, which can affect the ecosystem. Minimal concentrations of MP were observed in the tube well and drinking water, which depicts the direct risks to humans and, thus, the need for remedial measures to prevent MP contamination in drinking water. This study improves the knowledge of MP contamination in the higher-altitude freshwater lake, which can be the major pathway for the transport of MP to the rivers, and also emphasizes the need for waste management in Nainital town.

Environmental and ecological risk of microplastics in the surface waters and gastrointestinal tract of skipjack tuna (Katsuwonus pelamis) around the Lakshadweep Islands, India

The presence of microplastics (MPs) in marine ecosystems is widespread and extensive. They have even reached the deepest parts of the ocean and polar regions. The number of articles on plastic pollution has increased in recent years, but few have investigated the MPs from oceanic islands which are biodiversity hotspots. We investigated the possible microplastic contamination their source and characteristics in surface waters off Kavaratti Island and in the gastrointestinal tract (GT) of skipjack tuna, Katsuwonus pelamis collected from Kavaratti Island of the Lakshadweep archipelago. A total of 424 MP particles were isolated from the surface water samples collected from off Kavaratti Island with an average abundance of 5 ± 1nos./L. A total of 117 MPs were recovered from the GT of skipjack tuna from 30 individual fishes. This points to a potential threat of MP contamination in seafood around the world since this species has a high value in local and international markets. Fiber and blue color were the most common microplastic morphotypes and colors encountered, respectively, both from surface water and GT of fish. Smaller MPs (0.01-1 mm) made up a greater portion of the recovered materials, and most of them were secondary MPs. Polyethylene and polypropylene were the most abundant polymers found in this study. The Pollution Load Index (1.3 ± 0.21) of the surface water and skipjack tuna (1 ± 0.7) indicates a minor ecological risk for the coral islands, while the Polymer Hazard Index highlights the ecological risk of polymers, even at low MP concentrations. This pioneer study sheds preliminary light on the abundance, properties, and environmental risks of MPs to this highly biodiverse ecosystem.

Microplastics in oral healthcare products (OHPs) and their environmental health risks and mitigation measures

The environmental input of microplastics from personal care products has received significant attention; however, less focus has been paid to oral healthcare products. The present study assessed the occurrence of microplastics in commercially available oral healthcare products such as toothbrushes, toothpastes, toothpowder, mouthwash, dental floss, and mouth freshener spray that have a pan-India distribution. The extracted microplastics were quantified and characterised using a microscope and ATR-FTIR. All products showed microplastic contamination, where toothbrushes showed the maximum particles (30-120 particles/brush) and mouth freshener sprays (0.2-3.5 particles/ml) had the least abundance. Fragments, fibres, beads, and films were the various shapes of microplastics observed, where fragments (60%) were dominant. Various colours such as pink, green, blue, yellow, black, and colourless were observed, where colourless (40%) particles were dominant. Microplastics were categorized into three sizes: <0.1 mm (63%), 0.1-0.3 mm (35%), and >0.3 mm (2%). Four major types of polymers, such as polyethylene (52%), polyamide (30%), polyethylene terephthalate (15%), and polybutylene terephthalate (3%), were identified. Risk assessment studies such as Daily Microplastics Emission (DME), Annual Microplastics Exposure (AME), and Polymer Hazard Index (PHI) were carried out. The DME projection for India was the highest for mouthwash (74 billion particles/day) and the least for mouth freshener sprays (0.36 billion particles/day). The AME projection for an individual was the highest in toothbrushes (48,910 particles ind.-1 yr.-1) and the least in mouth freshener sprays (111 particles ind.-1 yr.-1). PHI shows that the identified polymers fall under the low-to high-risk categories. This study forecasts the community health risks linked to microplastics in oral healthcare products and suggests mitigation strategies. It has the potential to shape environmental policy development in response.

Evaluation of microplastic pollution and risk assessment in a tropical monsoonal estuary, with special emphasis on contamination in jellyfish

Estuaries, which serve as vital links between land and coastal ecosystems, play a significant part in facilitating the transfer of plastic waste from the land to the ocean. In this research, we examined the prevalence, characteristics, and ecological risks of microplastics (MPs) in the extensively urbanized Cochin Estuarine System (CES), India. Additionally, it represents one of the initial evidence-based examinations of MPs ingestion by jellyfish in Indian waters, focusing on Acromitus flagellatus, Blackfordia virginica, and Pleurobrachia pileus species. The abundance of MPs found in the surface water of the Cochin Estuarine System (CES) varied between 14.44 ± 9 to 30 ± 15.94 MP/m3, with an average of 21.6 ± 11 MP/m3. In both surface waters and jellyfish from the Cochin Estuarine System (CES), fibers were the most prevalent type of MPs, with polyethylene (PE), polypropylene (PP), and polyamide (PA) being the most common polymer varieties. To evaluate the current levels of MPs and their effect on the CES, the Pollution Load Index (PLI), Potential Ecological Risk Index (PERI), and Polymeric Risk Index (H) were utilized. The high PLIestuary values (20.33), high Hestuary values (234.02), and extreme PERIestuary value (1646.06) indicate that the CES is facing an extreme ecological risk. Among the 280 jellyfish individuals examined, 118 (42.14%) were recognized to contain MPs with an average of 1.54 ± 2.68 MPs/individual. Pearson bivariate analysis revealed a significant correlation between the jellyfish bell size and number of plastics per individual. Comparison between jellyfish species revealed, the majority (66%) of the MPs identified in jellyfish were from A. flagellatus and 44 among the 50 jellyfish examined (88%) had MPs. These findings suggest that A. flagellatus may be a potential sink for MPs and may be utilized to be a bioindicator for monitoring MPs contamination in estuarine systems, aiding in future plastic pollution mitigation efforts.

The path of microplastics through the rare biodiversity estuary region of the northern Bay of Bengal

Due to its harmful effects on ecosystems and human health, microplastic (MP) pollution has become a significant environmental problem on a global scale. Although MPs' pollution path and toxic effects on marine habitats have been examined worldwide, the studies are limited to the rare biodiversity estuary region of Hatiya Island from the northern Bay of Bengal. This study aimed to investigate the MP pollution path and its influencing factors in estuarine sediments and water in rare biodiversity Hatiya Island in the northern Bay of Bengal. Sixty water and sediment samples were collected from 10 sampling sites on the Island and analyzed for MPs. The abundance of MPs in sediment ranged from 67 to 143 pieces/kg, while the abundance in water ranged from 24.34 to 59 pieces/m3. The average concentrations of MPs in sediment and water were 110.90 ± 20.62 pieces/kg and 38.77 ± 10.09 pieces/m3, respectively. Most identified MPs from sediment samples were transparent (51%), while about 54.1% of the identified MPs from water samples were colored. The fragment was the most common form of MP in both compartments, with a value of 64.6% in sediment samples and 60.6% in water samples. In sediment and water samples, almost 74% and 80% of MP were <0.5 mm, respectively. Polypropylene (PP) was the most abundant polymer type, accounting for 51% of all identified polymers. The contamination factor, pollution load index, polymer risk score, and pollution risk score values indicated that the study area was moderately polluted with MPs. The spatial distribution patterns and hotspots of MPs echoed profound human pathways. Based on the results, sustainable management strategies and intervention measures were proposed to reduce the pollution level in the ecologically diverse area. This study provides important insights into evaluating estuary ecosystem susceptibility and mitigation policies against persistent MP issues.

Microplastic contamination in commercial fish feeds: A major concern for sustainable aquaculture from a developing country

Plastic pollution has become a global issue nowadays. Due to the increased population in developing countries, we largely depend on fish from our aquaculture industry to meet the required protein demand. Though several studies documented plastic ingestion in freshwater and marine organisms, very limited studies have been conducted to elucidate microplastic (MP) contamination in commercial fish feed. Therefore, this study was designed to identify, quantify, and characterize microplastics (MPs) in commercial fish feeds in Bangladesh and assess possible health risks in fish consuming different commercial fish feeds. All fish feed samples were 100 % contaminated with MPs, where the mean abundance of MPs ranged between 500 and 2200 MPs/kg. No significant differences among different types of feeds (e.g., starter, grower, and finisher) were observed in terms of MPs abundance (F = 0.999, p = 0.385). This study revealed that fiber was the most dominant shape of MPs (90 %), while the most dominant color of MPs was red (34 %), followed by black (31 %) and blue (19 %). The 100-1500 µm size class covers 88 % of the total MPs in the collected fish feed samples. Identified polymers in the samples were polyethylene (PE, 37.71 %), polyvinyl chloride (PVC, 27.14 %), polypropylene (PP, 22.08 %), and polyethylene terephthalate (PET, 13.07 %), respectively, where PE and PVC fall under the risk category IV to V. The Pollution load index (PLI) values of all fish feed samples were <10, indicating the risk category of I (low risk). Therefore, this study highly recommended avoiding plastic materials in the packaging and storing purposes of feed ingredients in the feed mills to ensure contamination-free fish feed for sustainable aquaculture.

The influence of media narratives on microplastics risk perception

Background

Media are the interface between scientists and citizens, communicating and interpreting the risk message and powerfully influencing individual awareness, public debate, and, hence, people's behavior. Pollution by microplastics (MPs), a threat to public health and terrestrial and marine ecosystems, has received research, media, and public interest. However, how MPs environmental and health risks are reflected in the media and assessed in the scientific literature does not find consensus over time. To date, few studies have examined social aspects around MPs, such as, for example, factors that influence awareness and perception of the risk of MPs. In this context, the objective of this study is twofold. First, we determined if media narratives influenced Romanians' awareness of MPs, and second, we investigated if media narratives influenced Romanians' perceptions of MPs health and environmental risk.

Method

An online survey was conducted among 417 Romanian respondents. The questionnaire had 21 questions. The questions were related to the awareness of MPs, the perceived health risk of MPs, the perceived environmental risk of MPs, the intensity of exposure to media narratives about the MPs impact on health and the environment, and the demographics. Binary logistic regression was run to identify what media narratives influenced MPs awareness and risk perception. In recent times, mass media has shaped perceptions of health and environmental risks, driven by events like COVID-19 and global climate change. Our study relies on media narratives as its foundation.

Results

Binary logistic regression showed that the awareness of MPs is influenced by the media narrative "Microplastics in the sea threaten fish stocks" (p = 0.001). When the frequency of exposure to this media narrative increases, the probability of reporting awareness of MPs increases. Likewise, an increase in age represents a higher probability of reporting awareness of MPs. The perceived health risk of MPs, with the highest weighting, was related to the dependent variable "Leakage of harmful chemicals from MPs affects the soil" (p = 0.014).

Conclusions

Media narratives about plastic and MPs pollution have increased over time, influencing the perception of this risk. The study argues the need for accurate and balanced media reporting on MPs to prevent the spread of misinformation and ensure that people clearly understand MPs risks. Furthermore, a closer examination of people's perceptions supports the design of appropriate interventions to reduce plastic consumption, thereby decreasing the risks of MPs pollution with benefits for human health and the environment.

Microplastic Pollution in the Gastrointestinal Tract and Gills of Some Teleost and Sturgeon Fish from the Caspian Sea, Northern Iran

The increasing microplastic pollution in the marine environment has raised global concern. The main risk of microplastics in aquatic ecosystem is their bioaccumulation in aquatic organisms. A few studies have reported microplastic pollution in the digestive system of Caspian Sea fish species, but there is no research on sturgeon species, nor on fish gills. We investigated the occurrence of microplastics in the gastrointestinal tract (GIT) and gills of 62 specimens belonging to four species including three teleosts (Cyprinus carpio, Rutilus kutum, and Chelon aurata) and one sturgeon (Acipenser persicus, a valuable endangered species) from the Caspian Sea between January and March 2022. Fish tissues were removed, exposed for 24 h to 10% KOH, and then dried on filter paper. Particles were observed under a stereomicroscope and analyzed by Raman microspectrometry, scanning electron microscopy, and energy-dispersive spectroscopy. A total of 91 microplastics were detected in the GIT (average of 1.46 ± 1.17 items/individual) and 63 microplastics in the gills (average of 1.01 ± 0.62 items/individual). A significant correlation was not found between the number of microplastics found in both tissues and fish body length, body weight, GIT weight, and gill weight (p > 0.05), except between microplastics isolated from gills and gill weight in C. carpio (rs  = 0.707, p = 0.022). The abundance of microplastics in fish followed the order of A. persicus > C. aurata > R. kutum > C. carpio. The microplastics were in the size range of 45 to 5000 µm, with particles of 300 to 1000 µm being the most prevalent; 74.68% of the particles were shaped like fibers, 30.53% were red, and 70.6% were composed of nylon polymer. Environ Toxicol Chem 2023;42:2453-2465. © 2023 SETAC.

Chromium (IV) transfer to Amusium pleuronectes by LDPE microplastics: An experimental study

An experiment was carried out to investigate the potential of virgin LDPE microplastics to transfer heavy metals. Desired shapes (fibres, fragments, and films) and sizes (< 5 mm) of virgin LDPE microplastics were immersed in a known concentration (30 µg/l) of chromium (IV). These Cr-coated microplastics were introduced into a culture tank containing edible scallops (Amusium pleuronectes). After the completion of the experiment (5 days), the sediments in the culture tank and edible tissues of A. pleuronectes were tested for the presence of Cr. In the sediments, a maximum concentration of 1.934 µg/g of Cr was accumulated at a rate of R2 = 0.979, while in the tissues, the maximum accumulation concentration was 0.733 µg/g of Cr at a rate of R2 = 0.807. Energy Dispersive X-ray Spectroscopy analysis also confirmed the presence of Cr (2.61 ± 0.44 mass % and 1.80 ± 0.30 atom%) in the tissues of A. pleuronectes, which was absent in the control tissues. The study showed that when exposed to contaminants such as heavy metals, LDPE microplastics can adhere and transfer them to biotic tissues. LDPE showed the potential to transfer adhered contaminants; however, the effects caused by these transferred contaminants on biota must be studied further. Risk assessment study showed that potential ecological risk of Cr is < 40 indicating low risk however, the combined effect of Cr and LDPE can compound its toxicity which needs to be studied further.

Microplastics in the marine environment of St. Mary's Island: implications for human health and conservation

Microplastics have now been identified as a class of emerging pollutants and is considered as a threat to aquatic organisms. This baseline paper investigated the distribution, composition, and potential ecological risks of microplastic (MP) pollution on St. Mary's Island, revealing an average abundance of 0.218 particles/L in water samples. Blue fibres and white foams were the primary MPs identified, and fishing activities and packaging were the main sources of pollution. Six types of polymers were identified: low-density polyethylene (LDPE), polystyrene (PS), polyamide (PA), polypropylene (PP), polyethylene (PE), and high-density polyethylene (HDPE). The Polymer Hazard Index (PHI) and Potential Ecological Risk Index (PERI) indicated a medium environmental risk for the island. Additionally, it was discovered that MPs' surfaces contained dangerous substances that could endanger aquatic life. The research emphasizes the significance of implementing measures such as responsible disposal, management, elimination, regulatory policies, and local administration techniques to mitigate the impact of MP pollution on the island's shores and marine biota. This research provides a baseline for monitoring MP contamination and underscores the need for continuous investigation to assess their impacts on marine life.

Risk assessments of microplastics accumulated in estuarine sediments at Cuddalore, Tamil Nadu, southeast coast of India

In this study, the abundance of microplastics (MPs) in the Uppanar and Gadilam estuaries in Cuddalore, on the southeast coast of India, is reported. In the estuarine sediments, MP abundance ranged from 36.3 ± 3.39 to 51.6 ± 2.05 particles/Kg dw. Different types of MP shapes, such as fibers (41.7-47.9%), films (21.2-27.2%), and fragments (18.3-25.5%) were observed in the size range of 100-1000 µm. Diverse colours of MPs were observed, among which red (30.1-34.5%) was predominantly noticed in the estuarine sediments. Six polymers were identified by µ-FTIR, among which LDPE (39%) and PP (35%) were dominant. MPs pollution in these estuaries is composed of domestic, industrial, and fishing wastes. Risk assessments show that the area falls under hazard categories I to III, indicating low to high risk. This study improves knowledge on MPs contamination in Uppanar and Gadilam estuaries and provides impetus for further research to identify the actual sources and impacts of MPs on aquatic systems along the east coast of India.

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

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

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.

Abundance, characteristics, and risk assessment of microplastics in indigenous freshwater fishes of India

Microplastic (MP) pollution has pressing concerns regarding environmental health and the availability of safe food for humans. Information on the occurrence of MP in freshwater biota in the Indian scenario is currently lacking. The present study examined MP contamination in edible and non-edible tissues of widely consumed freshwater fishes. All the fish species (n = 35/species) analyzed had microplastic contamination with the highest MP abundance of 7.86 ± 2.0 items/individual in Channa punctatus followed by Labeo rohita (4.17 ± 0.6 items/individual) and Labeo bata (3.03 ± 0.4 items/individual); whereas MP abundance in small indigenous fishes (SIF) such as Salmostoma bacaila and Puntius amphibius accounts for 0.83 ± 0.13 and 0.77 ± 0.2 items/individual respectively. The principal component analysis results showed a 77.434% variance from two components identified for MP distribution. Fibre type MP was the most dominant type besides fragments and pellets that opined the type of MP required for ecotoxicity assessment, the need of the hour. Raman spectroscopy analysis confirms high-density and low-density polyethylene-type polymers. Evidence of MP in edible tissue indicates the translocation phenomenon resulting in human exposure through the consumption of biota contaminated with MP. Risk assessment revealed a low risk of MP based on its abundance while polymer type indicates a high risk for the fish species investigated. A thorough investigation of the level of adsorbed organic contaminants in the MP is warranted to address the interactive effects on biota. To the best of our knowledge, this is the first detailed report on MP contamination and its risk assessment in Indian freshwater fishes.

Microplastic contamination in coral reef fishes and its potential risks in the remote Xisha areas of the South China Sea

Microplastics are recognized as a newly emerging threat to marine organisms as they can be ingested and accumulated through multiple trophic levels. However, microplastic contamination and its potential risk assessment in coral reef fishes have been less addressed, particularly in remote ocean regions. In this study, microplastics in 167 samples of coral reef fish (a total of eighteen species) from the Xisha areas of the South China Sea were studied. There were fifteen species of coral reef fish contaminated by microplastics with an average occurrence rate of 29.3 %. The shape of microplastics in the fishes was mostly fibrous with small sizes (400-900 μm) and light colors (transparent and blue). The dominant types of microplastic polymers are polyamide and polyethylene terephthalate, accounting for 77 % and 11 % of microplastics in the fish body. There were generally more microplastics in the herbivorous fishes than the carnivorous ones. The highest microplastic abundance and occurrence was found in parrotfish due to its direct feeding on the microplastics-contaminated corals. In addition, there were much more microplastics in the gastrointestinal tracts than in the gills of the Xisha fishes. Microplastic abundance was found negatively correlated with the trophic level of the Xisha fishes supporting a stronger microplastic impact at lower levels of marine animals. Finally, a risk assessment using the polymer hazard index (PHI) revealed that microplastic contamination in the Xisha fishes was lower than those in the eutrophic coast. Our study provides new evidence for the widespread presence of microplastic contamination in the fishes of the remote Xisha coral reefs.