Microplastic contamination in commercial goldfish (Carassius auratus) of Yuehai Lake via Laser Direct Infrared Imaging (LDIR)

Quantitative assessment of microplastic contamination in muddy shores of Gulf of Khambhat, India

Abundance, characteristics, and ecological risks of microplastics in the riverbed sediments around Dhaka city

Microplastic (MP) has been widely documented in aquatic environments; however, studies on MP distribution in aquaculture ponds remain limited. This study first evaluated MP ecological risks in aquaculture ponds along South Yellow Sea mudflat. The results showed MP concentrations of 32 ± 5 items/L in pond water and 253 ± 54 items/kg in sediment. MP loads varied significantly across pond types, with higher levels in crab ponds (38 ± 4 items/L, 314 ± 27 items/kg) and shrimp ponds (31 ± 3 items/L, 237 ± 22 items/kg) compared with fish ponds (27 ± 3 items/L, 209 ± 29 items/kg), indicating habitat-specific MP accumulation patterns. Morphological analysis revealed that fibrous MPs were predominant, accounting for 47.30 ± 18.18% of waterborne particles and 57.78 ± 16.19% of sedimentary particles. Size distribution analysis showed MPs in the 250 - 500μm range were most common (41.94 ± 13.35% in water and 43.09 ± 12.03% in sediment). Color analysis revealed a high proportion of transparent particles, while polymer characterization identified polyethylene (PE) as the dominant type, accounting for 33.62% of MPs in water and 34.62% in sediment. Ecological risk assessment showed that the pollution load index (PLI) values for water (1.17) and sediment (1.24) exceeded 1, indicating MP pollution in aquaculture ponds. The polymer risk index (PRI) scores corresponded to risk level Ⅲ for water (457.94) and sediment (399.40), primarily driven by the high hazard score of polyvinyl chloride. The potential ecological risk index (PERI), calculated as PRI × PLI, further revealed dangerous risk levels in both water (626.50) and sediment (618.92). These results demonstrate that aquaculture ponds face significant MP pollution risks, with contamination dynamics shaped by pond types and polymer characteristics. Such insights are valuable for developing MP control measures, improving pond management strategies, and safeguarding aquatic food security in anthropogenically influenced aquaculture systems.

Microplastics (MPs) are significant environmental pollutants that have rapidly garnered public attention due to their widespread presence and harmful effects on ecosystems and human health. While MP pollution in the coastal regions has been widely reported, their potential impacts on public health are still not fully understood. The current study examined MP contamination in nine commercially important fish and shellfish species collected from the coastal waters of Bangladesh, specifically from the Bay of Bengal. MP abundances (fiber, fragment, and microbeads) were evaluated in the gastrointestinal tract (GIT) and gills of fish and in the whole body of shellfish. Fibers were the most prevalent MP types found across the samples. In the case of gills, the highest abundance of MPs was found in Bombay duck, while the lowest was in pomfret. For GIT samples, hilsa showed the highest MP concentration, whereas the lowest was observed in bombay duck. Moreover, the highest level was observed in crabs, while the lowest was in squid (p < 0.05), likely because crabs are benthic feeders exposed to sediment-bound MPs, whereas squids are pelagic predators with lower exposure and more selective diets. Attenuated total reflectance Fourier transform infrared research revealed that the major polymer types were polymethyl methacrylate (43.33%), ethylene vinyl acetate (23.33%), nitrile butadiene rubber (1.67%), polypropylene (5%), polycarbonate (3.33%), acrylonitrile butadiene styrene (6.67%), nylon (5%), high-density polyethylene (1.67%), polyvinyl chloride (6.67%), and polyurethane (3.33%). MP contamination in fish and shellfish was assessed using contamination factor and pollution load index values, both below 10, indicating low to moderate pollution levels. The polymer hazard index further categorized the identified polymer types into risk levels ranging from low to very high, highlighting potential ecological and health concerns. These results underscore the urgent need for effective environmental management and continuous monitoring to mitigate MP-related risks.

This study investigated the extent of microplastic (MP) contamination in sediment and surface water from one of the largest shipbreaking yards along the Bay of Bengal coast. A total of 48 samples (24 each from sediment and water) were collected and analyzed to assess MP abundance, polymer characteristics, sources, and the associated potential ecological risks. MPs were extracted, identified using microscopy and FTIR spectroscopy, and classified by type, color, and polymer composition. MP concentrations averaged 73.54±8.61 items/kg in sediment and 218.56±19.12 items/m3 in water, with fibers being the dominant morphology (87.8-92.1% in sediment, 91.5-100% in water). Stations in close to intensive shipbreaking operations exhibited significantly higher abundances. Polymer characterization revealed PET as the dominant type, comprising 37.5% in water and 25% in sediment, followed by PS (25% in both matrices) and PP (12.5% in water and 25% in sediment). Ecological risk assessments revealed moderate to considerable contamination levels. Pollution Load Index (PLI) values ranged from 1.02 to 1.433 in sediment and 1.02-1.68 in water. Polymeric Hazard Index (PHI) values reached maximum at 254.37 (sediment) and 265.68 (water), with corresponding Ecological Risk Index (ERI) values reaching 312.88 and 433.06, respectively. Stations S6 and S3, located near areas of intensive shipbreaking activity, exhibited the highest ecological risks. These findings emphasized the urgent need for regulatory intervention and improved waste management.

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

Microplastic (MP) pollution in lacustrine environments remains largely overlooked in the South Asian region, despite its widespread presence and adverse effects. Hence, this pioneering study investigated the contamination levels and multi-approach ecological risks of MPs in water and sediment samples collected from ten key stations across Kaptai Lake, the largest artificial lake in South Asia. MPs abundance ranged from 650 to 2450 items/m3 in water and 135-607.5 items/kg in sediment. Significant spatial variation in MP concentrations (p<0.05) was observed along the lake. Their variation was influenced by polymer properties, local hydro-geography, and point pollution sources. The majority of identified MPs were fibers measuring less than 0.5mm in size, with transparent MPs being the most prevalent in both water (39.5%) and sediment (46.2%). FTIR analysis identified six polymer types including PE, PET, PP, PS, EVA, and PU. The detected polymers reflect diverse pollution sources e.g., primarily packaging materials, synthetic textiles, and fishing gear, originating from anthropogenic activities surrounding the lake. Evaluation through contamination indices, namely the contamination factor (CF) and pollution load index (PLI), revealed a moderate level of plastic contamination. However, high PHI values (>1000) observed at several locations indicate severe contamination, categorized under Hazard Level IV, indicating significant environmental risks. The PERI analysis showed considerable variability in risk levels across the lake, with certain areas classified as "extreme Danger" (>1200), highlighting severe ecological threats from MP contamination. Multivariate analyses (CA and PCA) revealed that human activities are likely the primary sources of MPs in the lake. These findings reveal pronounced spatial variations in MPs contamination and ecological risk across Kaptai Lake, underscoring the need for improved waste management and awareness initiatives around industrial, residential, and tourism-influenced zones.

Ecological risk assessment of microplastics contamination in water, sediment and native fish species of the Brahmaputra River, India.

Although a high percentage of microplastics (MP) are removed in wastewater treatment plants, a significant portion is released into the environment through wastewater discharges. The use of wastewater for irrigation transports microplastics to agricultural soil. Despite the increasing global use of treated and untreated wastewater for irrigation, especially in arid and semi-arid regions, the burden of microplastics reaching agricultural soils from wastewater has not yet been adequately investigated. Microplastic pollution in soil is a major concern with unknown consequences for sustainable agricultural activities. Within the scope of this study, microplastic accumulation in agricultural soils irrigated with urban wastewater for many years and the potential risks to agricultural ecosystems were investigated. For this purpose, 202 soil samples taken at depths of 0-10 cm and 10-20 cm from 11 control and 90 wastewater-irrigated soils were analyzed for microplastic quantity, color, shape, and polymer type. The risk level of microplastic pollution detected in the soil was determined by the pollution factor (CF), pollution load index (PLI), and polymer risk index (H). In addition, the relationship between some physicochemical properties of the soil and microplastics was analyzed. While the average microplastics counts in the control soils were 169 MP/kg (100-220 MP/kg) and 140 MP/kg (80-240 MP/kg) for soil depths of 0-10 cm and 10-20 cm, respectively, they were determined as 329 MP/kg (100-840 MP/kg) and 295 MP/kg (80-660 MP/kg) in soils irrigated with wastewater taken from the same soil depths. It was found that there was a significant difference (P&lt;0.0001) in terms of microplastic counts between the control and wastewater irrigated soils and that irrigation with wastewater caused an increase in the number of microplastics in the soil. It was observed that the number of microplastics detected decreased as the soil depth increased (P&lt;0.0141). In soils irrigated with wastewater, fiber (56-60%), film (20-23%), and fragment (15-16%) types of microplastics were predominant. Transparent colored microplastics were predominant in control (64-71%) and wastewater-irrigated soils (54-57%). Polyethylene (PE), cellophane (CP), and polypropylene (PP) polymers were predominant in both control and wastewater-irrigated soils. According to the pollution factor (CF) value, 50% of the soils at a depth of 0-10 cm and 64% of the soils taken from a depth of 10-20 cm were contaminated with significant amounts of microplastics. According to both point and regional pollution load index (PLI) values, the hazard category for microplastics is I (PLI&lt;10). As a result of the potential ecological risk assessment based on the types of polymers detected in the soil, 21% of the samples taken at both depths were found to be in the risk level III (100≤H&lt;1000) category, based on the polymer risk index (H) value. No significant change was observed in the number of microplastics with changes in pH and salinity. The number of microplastics detected increased as the amounts of organic matter, total nitrogen, and plant-available phosphorus detected in the soil increased. The study findings indicate that microplastic accumulation increases in agricultural soils irrigated with wastewater, posing a higher risk for more fertile soils with higher organic matter, total nitrogen, and available phosphorus contents. The risk assessment results reveal that agricultural soils irrigated with wastewater are at risk of microplastic contamination. The findings suggest that microplastics, a neglected type of soil pollution, will become an even more significant problem with increasing amounts of wastewater used for irrigation and the additional infiltration of sewage sludge into the soil. Therefore, when planning the reuse of wastewater in irrigation, it is recommended that it should also be evaluated in terms of microplastic pollution.

Microplastics (MPs) are a growing environmental concern due to their widespread occurrence, persistence, and ecological impacts. However, data on MP pollution in freshwater-dominated subtropical estuaries, particularly in South Asia, remain scarce. This study aimed to assess the spatial distribution, characteristics, sources, and ecological risks of MP contamination in the Feni River Estuary, Bangladesh. MPs were isolated by density separation, characterized by stereomicroscopy, and Fourier Transform Infrared spectroscopy. MP abundances ranged from 426.66 ± 140.23 to 546.66 ± 136.11 items/m 3 (mean: 468.33 ± 105.76 items/m 3 ), with no statistically significant variation among stations ( p &gt; .05). MPs were dominated by fibers, followed by fragments and films, with minor foams (porous plastics) and microbeads (spherical primary plastics). Polymer characterization identified polyethylene terephthalate (PET, 78%) as the dominant type, with polyethylene (PE), polypropylene (PP), and polystyrene (PS) also detected, reflecting strong consumer plastic inputs and secondary fragmentation processes. Contamination indices (CF) indicated non-negligible pollution, with both the contamination factor (CF, 1 ⩽ CF &lt; 3) and pollution load index (PLI &gt; 1) confirming moderate MP contamination. polymer hazard index (PHI) scores ranged from 0.1 to 9.1, placing polymers into risk categories I (&lt;1) and II (1–10). Notably, PS (9.1), PET (8.6), and PE (7.3) were classified as moderate ecological risks (Category II), whereas PP (0.1) posed a negligible risk (Category I). Multivariate analyses using principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed spatial heterogeneity in MP distribution, influenced by municipal discharge, aquaculture, industrial inputs, and estuarine hydrodynamics.

Microplastic (MP) pollution has been observed in various ecosystems as a result of the rapid increase in plastic production over the past half-century. Nevertheless, the extent of MP pollution in different ecosystems, particularly in freshwater ecosystems, has not been well-studied, and there are limited investigations on this particular topic, specifically in Türkiye. Here, we quantify the occurrence and distribution of MPs in surface water samples collected from Topçu Pond (Türkiye) for the first time. Water samples were collected at five stations and filtered (30 L for each station) through stacked stainless steel sieves (5mm, 328µm, and 61µm mesh size) with a diameter of 30cm. The abundance, size, color, shape, and type of collected debris samples were analyzed after the wet peroxide oxidation process. MP particles were observed in all samples at an average abundance of 2.4 MPs/L. The most abundant MP size class and type were 0-999µm and fiber respectively. On the other hand, prevalent colors were black and colorless in general. According to the Raman analysis results, the identified MP derivatives were polypropylene (40%), polyamide (30%), ethylene acrylic acid (20%), and polyvinylchloride (10%). Moreover, the pollution load index (PLI) index was used to determine the pollution status. PLI values were determined as 1.91 at station S1, 1.73 at station S2, 1.31 at station S3, 1 at station S4 and 1.24 at station S5. The PLI value determined for the overall pond was 1.4. The results of this research show that MP pollution is present in Topçu Pond and contributes to the expanding literature on MP pollution in pond ecosystems.

Microplastics (MPs) have been extensively studied in aquatic systems; however, their presence in general agricultural systems and in particular, soil still needs comprehensive understanding. This study conducted a field survey at 25 sites to investigate the abundance of MPs in agricultural soil. The MPs in these soil samples were separated using sieves and filters by the density separation method with NaCl solution (d = 1.2 g/cm3). The density of MPs in agricultural soils ranged from 1,700 items/kg to 38,800 items/kg, with an average of 11,716 ±10,726 items/kg. The black-colored MPs were found to be dominant, followed by white, purple, red, and blue. The fibers represented most of the MPs' shapes observed in this research (77.9±17.4%). MPs in agricultural soil samples were tiny particles with sizes of &lt;1,000 µm and 1,000-2,000 µm. A significant difference was observed in the concentration of MPs in locations near and far from residential areas and manufacturing facilities. The average concentration of MPs in the soils adjacent to the residential and manufacturing facilities and near the agricultural solid waste collection sites was 21,471±12,729 items/kg and 20,188±4,403 items/kg, much higher than in distant these locations at 4,418±1,573 items/kg. These results suggest that domestic, industrial, and agricultural activities could contribute to MP pollution in agricultural soil. The ecological dangers MPs pose in terrestrial and aquatic environments have drawn much attention from the scientific community. This work represented the first effort to comprehend the ecological risk of MPs on selected samples of Vietnamese agricultural soil. According to the Pollution Load Index (PLI) values, most agricultural soil samples in this study were contaminated with MPs at hazard level IV. The potential ecological risk index (PERI) values of agricultural soil samples from nearby residential, industrial, or agricultural solid waste areas indicated a higher ecological risk.

The pollution of microplastics in sediments: The ecological risk assessment and pollution source analysis

Application of machine learning and multivariate approaches for assessing microplastic pollution and its associated risks in the urban outdoor environment of Bangladesh

Although a high percentage of microplastics (MP) are removed in wastewater treatment plants, a significant portion is released into the environment through wastewater discharges. The use of wastewater for irrigation transports microplastics to agricultural soil. Despite the increasing global use of treated and untreated wastewater for irrigation, especially in arid and semi-arid regions, the burden of microplastics reaching agricultural soils from wastewater has not yet been adequately investigated. Microplastic pollution in soil is a major concern with unknown consequences for sustainable agricultural activities. Within the scope of this study, microplastic accumulation in agricultural soils irrigated with urban wastewater for many years and the potential risks to agricultural ecosystems were investigated. For this purpose, 202 soil samples taken at depths of 0-10 cm and 10-20 cm from 11 control and 90 wastewater-irrigated soils were analyzed for microplastic quantity, color, shape, and polymer type. The risk level of microplastic pollution detected in the soil was determined by the pollution factor (CF), pollution load index (PLI), and polymer risk index (H). In addition, the relationship between some physicochemical properties of the soil and microplastics was analyzed. While the average microplastics counts in the control soils were 169 MP/kg (100-220 MP/kg) and 140 MP/kg (80-240 MP/kg) for soil depths of 0-10 cm and 10-20 cm, respectively, they were determined as 329 MP/kg (100-840 MP/kg) and 295 MP/kg (80-660 MP/kg) in soils irrigated with wastewater taken from the same soil depths. It was found that there was a significant difference (P&lt;0.0001) in terms of microplastic counts between the control and wastewater irrigated soils and that irrigation with wastewater caused an increase in the number of microplastics in the soil. It was observed that the number of microplastics detected decreased as the soil depth increased (P&lt;0.0141). In soils irrigated with wastewater, fiber (56-60%), film (20-23%), and fragment (15-16%) types of microplastics were predominant. Transparent colored microplastics were predominant in control (64-71%) and wastewater-irrigated soils (54-57%). Polyethylene (PE), cellophane (CP), and polypropylene (PP) polymers were predominant in both control and wastewater-irrigated soils. According to the pollution factor (CF) value, 50% of the soils at a depth of 0-10 cm and 64% of the soils taken from a depth of 10-20 cm were contaminated with significant amounts of microplastics. According to both point and regional pollution load index (PLI) values, the hazard category for microplastics is I (PLI&lt;10). As a result of the potential ecological risk assessment based on the types of polymers detected in the soil, 21% of the samples taken at both depths were found to be in the risk level III (100≤H&lt;1000) category, based on the polymer risk index (H) value. No significant change was observed in the number of microplastics with changes in pH and salinity. The number of microplastics detected increased as the amounts of organic matter, total nitrogen, and plant-available phosphorus detected in the soil increased. The study findings indicate that microplastic accumulation increases in agricultural soils irrigated with wastewater, posing a higher risk for more fertile soils with higher organic matter, total nitrogen, and available phosphorus contents. The risk assessment results reveal that agricultural soils irrigated with wastewater are at risk of microplastic contamination. The findings suggest that microplastics, a neglected type of soil pollution, will become an even more significant problem with increasing amounts of wastewater used for irrigation and the additional infiltration of sewage sludge into the soil. Therefore, when planning the reuse of wastewater in irrigation, it is recommended that it should also be evaluated in terms of microplastic pollution