Microplastic pollution and its implicated risks in the estuarine environment of Tamil Nadu, India

Characterization and risk assessment of microplastics accumulated in sediments and benthic molluscs in the mangrove wetlands along the south-west coast of India

In the present study, occurrence and characteristics of microplastics in mangrove sediments and benthic molluscs viz., black clam (Villorita cyprinoides), yellow clam (Meretrix casta), mangrove horn snail (Telescopium telescopium) and brackish water snail (Neripteron violaceum) were studied from mangrove habitats of Vembanad Lake, the largest estuary and a Ramsar site on the south-west coast of India. The average microplastic abundance in mangrove sediments varied between 235 ± 49.5 and 1414 ± 182 items/kg dry weight, with an average concentration of 673.45 ± 365.05 items/kg dry weight, which was at a relatively higher level compared to other mangrove regions of India. The highest abundance was recorded for gastropod T. telescopium (38.5 ± 11.48 items/individual). The predominant shape, colour and size of microplastic in mangrove sediment and molluscs were fragments, black and < 500 μm, respectively. The major polymers identified were polyethylene and polypropylene in sediments and molluscs. Higher values of ecological risk indices (Microplastic index and Microplastics diversity integrated index) indicated a severe microplastic pollution risk for the molluscs in the mangroves. The high bio-accumulation factor also highlights the possibility of using these species as bioindicators of plastic pollution in mangrove habitats. The results of the present study could be useful to prepare effective management strategy to minimize plastic pollution load in mangrove habitats.

Unseen toxins: Exploring the human health consequences of micro and nanoplastics

Micro and nanoplastics (MNPs) contamination constitute a pressing global issue with considerable ramifications for human health. Particles originating from the decomposition of plastic waste permeate ecosystems and disturb biological systems, especially the gastrointestinal (GI) tract. MNPs compromise the intestinal barrier, provoke oxidative stress, inflammation, and immunological dysfunction, and modify gut microbiota, which is associated with metabolic problems, inflammatory bowel disease (IBD), and colorectal cancer. MNPs traverse biological barriers beyond the gastrointestinal system, including the blood-brain barrier, colonic mucus layer, and placental barrier, resulting in accumulation in essential organs such as the liver, kidneys, and brain. This results in inflammatory damage, metabolic abnormalities, and oxidative stress, specifically affecting liver disease due to microbiota metabolite alteration and nephrotoxicity in the kidneys. Airborne MNPs pose an additional risk to respiratory health, aggravating ailments such as asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. At-risk groups, such as pregnant women, newborns, and the elderly, encounter increased dangers, as MNPs traverse the placental barrier and may induce neurological and intergenerational health consequences. These particles function as vectors for environmental pollutants, exacerbating their cardiovascular and neurological effects. Addressing the long-term consequences of MNP exposure necessitates interdisciplinary collaboration to enhance comprehension and alleviate their growing risk to human health.

Comprehensive analysis of microplastics in water, sediment and fish from a large recreational lake

While global attention has primarily focused on microplastics (MPs) in marine ecosystems, the issue of MP pollution in recreational lakes has received relatively little attention. In this study, the occurrence, spatial and seasonal distribution and characteristics of microplastics (MPs) were investigated for the first time in Lake Hazar (Türkiye), an important recreational lake. Water, sediment and fish (Capoeta umbla) were sampled from the lake in the winter and summer of 2020. Thereafter, the MPs were extracted from the samples using the density separation method. Their abundance, shape, color, and size were determined microscopically, while the polymer types were analyzed using ATR-FTIR. The MPs were detected in all surface water and sediment samples, while they were detected in the gastrointestinal tracts of 28 (35 %) out of 80 fish samples. The abundance of MPs was 74-1091 items/m3 for the surface water, 88-213 items/kg (ww) for sediments and 0-5 items/fish for C. umbla, respectively. The MP concentrations in water samples from the shore sites were found to be significantly higher than those in limnetic sites (p < 0.05). The most common MP shapes, sizes and colors were fragments, <0.5 mm and white/transparent, respectively. Polyethylene and polypropylene were the most common polymer types, indicating that recreational activities and fishing activities may be the main sources of MPs in the lake. The Pollution Load Index results indicated that MP pollution in the lake's water and sediments was at a moderate level.

Ecological risk assessment and ingestion of microplastics in edible finfish and shellfish species collected from tropical mangrove forest, Southeastern India

In the Pichavaram mangroves in Southeast India, this study examines the seasonal trends and consumption of microplastic (MPs) by several fish and shellfish species. Four different seasons viz. summer, pre-monsoon, monsoon, and post-monsoon were used to gather the fish and shellfish samples from Pichavaram Mangrove Forest. The results of the present investigation revealed that MP abundance was higher during the monsoon (45 %), suggesting seasonal runoff and increased plastic pollution during heavy rains as key contributors. We observed microplastics in Liza tade (mullet), with 13.33 MPs/individuals in the summer, 0.77 MPs/individuals in the pre-monsoon, 6.3 MPs/individuals in the monsoon, and 2.67 MPs/individuals in the post-monsoon. A significant proportion (32 %) of MPs were smaller than 1 mm. The fibres were predominated with blue (40 %) and red (13 %). The polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) were the primary polymers, according to μ-Raman spectroscopy. The fish species Liza tade and Etroplus suratensis showed the highest levels of contamination, while the shellfish species Portunus sanguinolentus and Scylla serrata did the same. Comparative global analyses reveal that mangrove ecosystems across different regions exhibit the presence of similar polymer types, but microplastic sources vary greatly from place to place. This work highlights the pervasive nature of MPs, their complex seasonal behavior, and their ecological implications, advocating for targeted mitigation strategies to address MP pollution and its potential risks to marine life and ecosystems.

Influence of anthropogenic pressures on the microplastic distribution in the riverine-estuarine environment: A source-apportioning approach

In this study, the influence of anthropogenic pressures, namely fishing practices and illicit and unregulated wastewater and solid waste discharge, on the microplastic distribution in India's Kallada River - Ashtamudi riverine-estuarine environment was investigated. To better characterize microplastic pollution in the Estuary, it was subdivided into cage farming, open fishing, solid waste dumping, and other zones that receive wastewater from residential areas. A source-apportioning approach was utilized to delineate the possible sources of pollution and conducted a risk assessment attributed to exposure to microplastic pollution. The results suggest that the solid waste dumping zone exhibited the highest microplastic abundance, followed by the cage farming zone. Fiber-shaped microplastic particles were abundant in cage farming and open fishing zones, while films dominated the solid waste dumping zone. FTIR analysis revealed that polyamide and polyester, widely used for regional fishing nets, were dominant in cage farming and open fishing zones, while polyamide, polystyrene, and polyethylene were dominant in solid waste dumping zones. Other zones impacted by the unregulated discharge of domestic wastewater exhibited an abundance of polyester and polyethylene microplastics. Source apportionment studies using a modified approach incorporating morphological and chemical characteristics of microplastics revealed that fishing nets/ropes contributed to 35.48 % of microplastic pollution, followed by single-use plastics and plastic bags/covers (19.35 % each), textile fabrics (16.13 %) and personal care products (9.68 %). A risk assessment analysis considering microplastic abundance and polymer hazard revealed that the solid waste dumping zone and the cage farming zone pose a medium risk to microplastic pollution. These findings highlight the role of fishing practices and solid waste dumping on the microplastic pollution in the riverine-estuarine environment.

A systematic review to assess current surface water and sediment microplastic sampling practices in seagrass and mangrove ecosystems

Global plastic production is estimated to be 400 million tonnes per annum, with ~ 5.25 trillion fragments floating in our oceans. Microplastics (< 5 mm) have the potential to disproportionately accumulate and become trapped in mangroves and seagrass meadows, creating plastic 'sinks'. This is concerning as these ecosystems are of great ecological and economic importance, with microplastics causing harm to inhabiting flora and fauna. However, accurately measuring microplastic abundance, comparing findings, and determining potential impacts are difficult due to a lack of standardised sampling protocols. Therefore, a systematic literature review was completed to review currently adopted microplastic sampling methods in surface water and sediment in seagrass and mangrove ecosystems. These were compared with recommendations from existing governmental and institutional groups as a first step to standardising methods for future sampling procedures in seagrasses and mangroves.

Ecological risk assessment and characterization of microplastics in the beach sediments of southeast coast of India

This study explores spatiotemporal variations of microplastics (MPs) in beach sediments along India's southeast coast, focusing on Tamil Nadu and Puducherry from 2020 to 2021. The MPs were extracted from the sediments through density separation and wet peroxidation. Following extraction, they were quantified and physically characterized using stereo-microscopy and chemically analyzed using ATR-FTIR. During the monsoon, Chennai (923 ± 380 MPs/kg) exhibited the highest MP abundance, followed by Puducherry (805 ± 222 MPs/kg), Nagapattinam (799 ± 257 MPs/kg), Thoothukudi (653 ± 258 MPs/kg), Rameswaram (585 ± 151 MPs/kg), and Kanyakumari (344 ± 71 MPs/kg). Similarly, in summer, Chennai (719 ± 192 MPs/kg) recorded the highest mean, trailed by Puducherry (645 ± 163 MPs/kg), Rameswaram (529 ± 138 MPs/kg), Nagapattinam (523 ± 95 MPs/kg), Thoothukudi (492 ± 104 MPs/kg), and Kanyakumari (335 ± 72 MPs/kg). Fibers predominated as the most common MP type. FTIR revealed polymers like polystyrene, polyethylene terephthalate, polyethylene, polypropylene, polyurethane, and polyamide. The Polymer Hazard Index indicated high polymer pollution risk, while the Pollution Load Index showed minimal contamination. The Potential Ecological Risk Index revealed low-to-medium MP pollution levels. Tailored strategies addressing plastic usage reduction and mitigation of terrestrial MP sources are imperative for coastal ecosystem resilience.

The abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (Fundulus heteroclitus): a pilot study

Microplastics (MPs) have been found in a diverse range of organisms across trophic levels. While a majority of the information on organismal exposure to plastics in the environment comes from gastrointestinal (GI) data, the prevalence of MP particles in other tissues is not well understood. Additionally, many studies have not been able to detect the smallest, most prevalent, MPs (1 µm - 5 mm) that are the most likely to distribute to tissues in the body. To address these knowledge gaps, MPs in the GI tract and muscle of Atlantic killifish (Fundulus heteroclitus) collected from two sites (Falmouth and Bourne) on Buzzards Bay, Cape Cod, MA were quantified down to 2 µm in size. Eight fish from Falmouth and 10 fish Bourne site were analyzed. Fourier-transform infrared spectroscopy and Raman spectroscopy were used to identify all particles. The mean concentrations of MPs in the GI tract and muscle from fish collected from Falmouth was 85.5 ± 70.2 and 11 ± 12.5 particles per gram wet weight, respectively. Fish collected from Bourne site had mean particle concentrations of 12.2 ± 18.1 and 1.69 ± 5.36 particles per gram wet weight. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4% (69 particles) were identified as plastic; polymers included nylon, polyethylene, polypropylene, and polyurethane. MPs detected in the GI tract samples also tended to be more diverse in both size and polymer type than those found in the muscle. We found that MPs < 50 µm, which are often not analyzed in the literature, were the most common in both the GI tract and muscle samples. There was not a significant correlation between the MP content in the muscle compared to the GI tract, indicating that GI tract MP abundance cannot be used to predict non-GI tract tissue MP content; however, MP abundance in muscle correlated with fish total length, suggesting potential bioaccumulation of these small MPs.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s43591-024-00101-w.

One-stop quantification of microplastics and nanoparticles based on meniscus self-assembly technology

Micro-nano plastics (MNPs) pollution is currently a hot topic of global concern. However, there is still a lack of reliable analytical methods for completely quantitative analysis of MNPs, especially nanoplastics. This study proposes meniscus self-assembly enrichment method, which deposits nanoplastics more uniformly in a specific area. The meniscus self-assembly method greatly overcomes the agglomeration or dispersion of nanoplastics caused by traditional enrichments, and facilitates particles counting. This study investigates the effect of key parameters (e.g. time and initial concentration) on meniscus self-assembly enrichment performance. Besides, due to the large size difference between MNPs, it leads to incomplete quantification analysis when MNPs are counted at the same scale. In response to this problem, this study proposes a one-stop method to count MNPs separately through filtering. The plastics (>1 μm) are collected on the filter paper, then plastics (<1 μm) in the filtrate are homogeneously enriched by meniscus self-assembly, and finally statistically counted by scanning electron microscopy (SEM). The migration of MNPs from take-out plastic containers are detected, with microplastics of 460.55 particles/mL and nanoplastics of 4196.61 particles/mL found. The method has the advantages of saving time and effort, economic efficiency and comprehensive statistics compared with the traditional method.

The estuarine plastics menace: Insights into prevalence, characterization and polymeric risk assessment of microplastics in the Mahi River Estuary, Gujarat, India

Microplastic contamination (MP) has created havoc in all eco-systems especially the estuarine environment. The current investigation focused on assessing MP contamination along the Mahi River Estuary in Gujarat. Thirty sampling sites were selected along the estuary, spanning from Khambhat to Kamboi. Sediment samples were collected, processed, and analyzed for MPs. A total of 1371 MP particles were found, with an average abundance of 0.76 ± 0.25 MPs/g dry weight. The MP abundance was recorded at its highest and lowest at Chokari and Umraya, respectively. The MP abundance varied significantly between study sites. Fibers were reported dominantly, followed by fragments, films, and foam. Size-wise, 1-2 mm and <1 mm-sized MPs were prevalent. Various colours of MPs were also recorded. Polyethylene tetraphene, polyethylene, and polypropylene are the most abundant. Tourism, fishing activities, and a lack of waste management practices can be the possible reasons for MPs input in to estuarine habitats.

Characterization and ecological risk assessment of microplastics accumulated in sea water, sand, sediment, shell water and selected tissues of hermit crab of Sundarban Biosphere Reserve

Sundarban, a Ramsar site of India, has been encountering an ecological threat due to the presence of microplastic (MP) wastes generated from different anthropogenic sources. Clibanarius longitarsus, an intertidal hermit crab of Sundarban Biosphere Reserve, resides within the abandoned shell of a gastropod mollusc, Telescopium telescopium. We characterized and estimated the MP in the gills and gut of hermit crab, as well as in the water present in its occupied gastropod shell. The average microplastic abundance in sea water, sand and sediment were 0.175 ± 0.145 MP L-1, 42 ± 15.03 MP kg-1 and 67.63 ± 24.13 MP kg-1 respectively. The average microplastic load in hermit crab was 1.94 ± 0.59 MP crab-1, with 33.89 % and 66.11 % in gills and gut respectively. Gastropod shell water exhibited accumulation of 1.69 ± 1.43 MP L-1. Transparent and fibrous microplastics were documented as the dominant polymers of water, sand and sediment. Shell water exhibited the prevalence of green microplastics followed by transparent ones. Microscopic examination revealed microplastics with 100-300 μm size categories were dominant across all abiotic compartments. ATR-FTIR and Raman spectroscopy confirmed polyethylene and polypropylene as the prevalent polymers among the five identified polymers of biotic and abiotic components. The target group index indicated green and black as the preferable microplastics of crab. The ecological risk analysis indicated a considerable level of environmental pollution risk in Sundarban and its inhabiting organisms. This important information base may facilitate in developing a strategy of mitigation to limit the MP induced ecological risk at Sundarban Biosphere Reserve.

Insights into the seasonal distribution of microplastics and their associated biofilms in the water column of two tropical estuaries

The present study describes the seasonal distribution of microplastics (MPs) and their associated biofilms in the water column of the Netravathi-Gurupura estuary, southwest India. An average abundance of 8.15 (±3.81) particles/l and 1.14 (±0.78) particles/l was observed during the wet and dry seasons, respectively. Fibres, films, and fragments accounted for majority of the microplastics. Polyethylene terephthalate, polyethylene, polyurethane, polyester, polystyrene, and high-density polyethylene were the major polymers. The risk assessment revealed a low Pollution Load Index, but the Polymer Hazard Index showed higher toxicity. Diatoms from nine genera were observed attached to the microplastic samples with Amphora and Navicula spp. reported in both estuaries during both seasons. The considerable diversity of diatoms, along with other microbial groups, in microplastic-associated biofilms in this study, highlights the urgent need to understand the structure and development of microplastic-associated biofilms and their role in the vertical and horizontal transport of microplastics in tropical estuaries.

First Data on Anthropogenic Microparticles in the Gastrointestinal Tract of Juvenile Scalloped Hammerhead Sharks (Sphyrna lewini) in the Gulf of California

Scalloped hammerhead sharks (Sphyrna lewini) are critically endangered, according to the International Union for Conservation of Nature Red List, likely due to anthropogenic activities such as intense fishing and pollution. Nowadays, plastic debris contamination is a subject of concern due to its extensive presence in the sea and the digestive tracts of many fish species. The possible effects of plastic debris as a vector of other pollutants are still unknown. We analyzed the digestive tract of 58 hammerhead sharks to investigate the correlation between plastic and other anthropogenic microparticle contamination and their feeding habits in the eastern region of the Gulf of California, revealing a debris contamination occurrence of 79.3%. Out of these, 91.4% corresponded to fibers, and the remaining 8.6% to fragments. The main component of the debris was cellulose (64.4%). According to their diet, these organisms exhibit benthopelagic habits, feeding both in the water column and on the seabed. These results indicate a high level of contamination of anthropogenic cellulosic microfibers in the area. Although cellulosic microfibers are recognized as a biomaterial, they can be harmful to marine species, posing an additional threat to this iconic shark. This changed according to the year, indicating that the anthropogenic microparticle ingestion is related to the discharges of human activities and their seasonality rather than to a selection process by the sharks.

Assessment and accumulation of microplastics in the Indian riverine systems: Risk assessment and implications of translocation across the water-to-fish continuum

Microplastic (MP) pollution has engulfed global aquatic systems, and the concerns about microplastic translocation and bioaccumulation in fish and other aquatic organisms are now an unpleasant truth. In the past few years, MP pollution in freshwater systems, particularly rivers and subsequently in freshwater organisms, especially in fish, has caught the attention of researchers. Rivers provide livelihood to approximately 40 % of the global population through food and potable water. Hence, assessment of emerging contaminants like microplastics in rivers and the associated fauna is crucial. This study assessed microplastics (MPs) in fish, sediment and freshwater samples across the third largest riverine system of peninsular India, the Mahanadi River. The number concentrations of MPs measured in water, sediment and fish ranged from 337.5 ± 54.4-1333.3 ± 557.2 MPs/m3, 14.7 ± 3.7-69.3 ± 10.1 MPs/kg. Dry weight and 0.4-3.2 MPs/Fish, respectively. Surprisingly, MPs were found in every second fish sample, with a higher MP number in the gut than in the gills. Black and blue coloured filaments with <0.5 mm size were the dominant MPs with polypropylene and polyethylene polymers in abundance. The Polymer Hazard Index (PHI) and the Potential Ecological Risk Index (PERI) studies revealed that the majority of the sampling sites fell in Risk category V (dangerous category). An irregular trend in the MP concentration was observed downstream of the river, though relatively elevated MP concentrations in water and fish samples were observed downstream of the river. t-Distributed Stochastic Neighbour Embedding (t-SNE) unveiled distinct patterns in MP distribution with a higher similarity exhibited in the MPs found in fish gill and gut samples, unlike water and sediment, which shared certain characteristics. The findings in the current study contribute to filling the knowledge gap of MP assessment and accumulation in global freshwater systems and highlight the microplastic contamination and accumulation in fish with its potential implications on human health.

Pollution characteristics and prospective risk of microplastics in the Zhengzhou section of Yellow River, China

The ubiquitous occurrence of microplastics (MPs) in the freshwater has attracted widespread attention. The Zhengzhou section of the Yellow River was the most prosperous region in ancient China, and the rapid urbanization, industrialization, and agricultural practices contributed to MPs pollution in aquatic systems recently, whereas the contamination status of MPs in the area is still not available. In this study, a total of fourteen sampling cross-sections were selected in the region to collect water samples systematically for the analysis of MPs pollution characteristics and potential risks. Results showed that abundance of MPs in the water were ranged from 2.33 to 15.50 n/L, with an average value of 6.40 ± 3.40 n/L, which was higher than it in other inland rivers from China. Moreover, the MPs of 0.5-2 mm were the dominant sizes in Yellow River of Zhengzhou region, and most of them were black fibres. The top three polymers were Polyethylene terephthalate (PET), Polyamide (PA) and Polypropylene (PP). High diversity indices of MPs observed at S3, S4, S5, S6, S7, and S8 for size, colour, polymer and shape indicated diverse and complex sources of MPs in those cross-sections. The MPs in water from Zhengzhou area of Yellow River probably degraded from textiles, fishing net, plastic bags, mulching film, packaging bags, and tire wear. The chemical risk assessment revealed a level III risk for study area, while S8 and S11 in which PVA or PAN with higher hazard score detected were categorised as class V risk. Coincidentally, probabilistic risk assessment showed a considerable ecological risk of MPs from Yellow River in Zhengzhou City, with possibility of 99.48 and 98.01 % adverse effect for food dilution and translocation-mediated mechanism, respectively. The results are expected to assistance for development of policies and ultimately combating MPs pollution.

Microplastic contamination in Ashtamudi Lake, India: Insights from a Ramsar wetland

Estuaries function as temporary storage sites for plastic debris, influencing the distribution of microplastics (MPs) across ecosystems. This research delves into the presence of MPs in the water, sediment, fish, and shellfish of Ashtamudi Lake, a Ramsar wetland with brackish water located on the southwest coast of India. Given the lake's significance in supporting the livelihoods of numerous fishers and acting as a vital source of fishery resources for both local consumption and export, examining the contamination of the system by MPs becomes particularly pertinent. The highest percentage composition of MPs was found in macrofauna at 60.6% (with fish at 19.6% and shellfish at 40.9%), followed by sediment (22.8%) and water (16.7%). The primary types of MPs identified in all samples were fibers (35.6%), fragments (33.3%), and films (28%), with beads being the least represented at 3.03%. ATR-FTIR and Raman spectra analysis identified five polymers from shellfish (polypropylene, polyethylene, polystyrene, nylon, and polyvinyl chloride), five from fish guts (nylon, polypropylene, polyethylene, polyurethane, and polysiloxane), four in sediment (polypropylene, polyethylene, nylon, rayon), and four in water samples (polypropylene, polyethylene, nylon, and polystyrene). SEM-EDAX analysis of MPs obtained from the samples revealed degradation and the presence of inorganic elements such as Na, Mg, Al, Si, S, K, Cl, P, and Ca, as well as heavy metals like Pb, Mo, Rh, Pd, Ti, and Fe. The existence of these plastic polymers and heavy metals in microplastic samples poses a threat to vulnerable biota; people consume contaminated fish and shellfish, underscoring the importance of monitoring MPs in lake water. This investigation of MPs in Ashtamudi Lake highlights the system's susceptibility to plastic pollution and the bioavailability of smaller MPs to aquatic organisms. Identified sources of MPs in the lake include fishing and aquaculture activities, sewage pollution, improper solid waste management in lake watersheds, and unsustainable tourism. Upstream and downstream management interventions are recommended to address MP pollution in Ashtamudi Lake.

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.

Recent trends on microplastics abundance and risk assessment in coastal Antarctica: Regional meta-analysis

We investigated sources, abundance and risk of microplastics (MPs) in water, sediments and biota around Antarctica. The concentration of MPs in Southern Ocean (SO) ranged from 0 to 0.56 items/m³ (mean = 0.01 items/m³) and 0-1.96 items/m³ (mean = 0.13 items/m³) in surface and sub-surface water. The distribution of fibers in water was 50%, sediments were 61%, and biota had 43%, which were followed by fragments in the water (42%), sediments (26%), and biota (28%). Shapes of film had lowest concentrations in water (2%), sediments 13%), and biota (3%). Ship traffic, drift of MPs by currents, and untreated waste water discharge contributed to the variety of MPs. The degree of pollution in all matrices was evaluated using the pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk index (PERI). PLI at about 90.3% of locations were at category I followed by 5.9% at category II, 1.6% at category III, and 2.2% at category IV. Average PLI for water (3.14), sediments (6.6), and biota (2.72) had low pollution load (<10). Mean PHI for water, sediments, and biota showed hazards level V with a higher percentage of 84.6% (>1000) and 63.9% (PHI:0-1) in sediments and water, respectively. PERI for water showed 63.9% minor risk, and 36.1% extreme risk. Around 84.6% of sediments were at extreme risk, 7.7% faced minor risk, and 7.7% were at high risk. While 20% of marine organisms living in cold environments experienced minor risk, 20% were in high risk, and 60% were in extreme risk. Highest PERI was found in the water, sediments, and biota in Ross Sea, due to high hazardous polymer composition of polyvinylchloride (PVC) in the water and sediments due to human activity, particularly use of personnel care products and waste water discharge from research stations.