Microplastics in Urban Soils of İstanbul: Distribution Patterns and Seasonal Changes

SummaryBackgroundThere is widespread concern regarding the effect of microplastics (MPs) on human reproductive health. The accumulation of MPs and their potential effect on adverse pregnancy outcomes must be determined, particularly from the perspective of the maternal–foetal interface during early gestation, because abnormal composition and metabolism of chorionic villi are closely related to early embryonic development. This study aimed to identify and quantify the mean mass concentrations and polymer types of MPs in human chorionic villi, and investigate the potential association between the abundance of MPs and spontaneous miscarriage.MethodsChorionic villi were collected from 31 participants in their first trimester, including normal carriage terminated for social factors (NC, n = 13) and unexplained spontaneous miscarriage (SM, n = 18). Qualitative and quantitative detection of 11 types of MPs was performed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Differences in the abundance of specific MPs between the two groups were analysed by t-tests. Individual clinical characteristics and lifestyle information were collected to identify the primary sources and factors that may impact MPs in chorionic villi. Statistical analyses, including a correlation analysis and the binary logistic regression model, were used to assess the effect of MP accumulation on early pregnancy outcomes.FindingsMPs were detected in all samples and four main types were identified, namely polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and polypropylene (PP). PVC was the most abundant. The total abundance of MPs in patients with SM was significantly higher than that in controls (273.08 ± 50.89 μg/g vs 226.37 ± 42.35 μg/g, p = 0.011). The accumulation of total MPs (r = 0.5947, p < 0.01) and PVC (r = 0.5649, p < 0.05) in patients with SM was positively correlated with age but not body mass index. Participants who regularly consumed bottled water generally showed significantly elevated levels of PE and total MPs in their villi, while frequent seafood consumption had a significant effect on PE, PVC, PS, and PP concentrations.InterpretationWe identified the presence of MPs in chorionic villi during the first trimester and established an association between the abundance of MPs and unexplained SM. These findings suggest that accumulation of MPs at the maternal–foetal interface during the first trimester are related to an increased risk of miscarriage and that these cross-generational effects during early gestation represent potential reproductive toxicity of MPs. Further research is warranted to elucidate the underlying mechanisms, and larger sample sizes are required to validate the observed trends.FundingThis study was supported by grants from the “Pioneer” and “Leading Goose” R&D Program of Zhejiang (2024C03242) and the Medical Science Projects of Zhejiang Province (No. 2023KY013).

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

Microplastics in urban soils of Nanjing in eastern China: Occurrence, relationships, and sources.

Intensive management practices promote microplastic (MP) accumulation in Phyllostachys violascens forests, posing potential threats to ecosystem stability and the edibility safety of bamboo shoots. However, how urbanization and mulching duration jointly regulate MP distribution, transfer, and associated food safety risks remains unclear. We investigated MP dynamics across urban–rural gradients (suburban vs. exurban) under different mulching durations (no mulching, short–term mulching, and long–term mulching), focusing on the rhizome–root–soil system and bamboo shoots. MP abundance was significantly higher in suburban forests, with maxima under long–term mulching, whereas in exurban forests, peaks occurred under long–term mulching. Urbanization also altered MP allocation patterns, with enrichment in rhizome roots and rhizomes in suburban forests but greater accumulation in bamboo shoots in exurban forests. Long–term mulching markedly enhanced MP accumulation across all components, particularly in clump roots, where abundance was three times higher than that in exurban forests. MPs were predominantly small (20–50 μm), mainly composed of acrylates (ACRs), polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET), polyurethane (PU), and polyethylene (PE). Along the “soil–root–rhizome” continuum, contrasting transfer patterns emerged between suburban and exurban forests, with soil total potassium identified as the key driver regulating MP migration and redistribution. Although the pollution load index indicated moderate contamination without significant accumulation in bamboo shoots, the ecological risk index revealed a high ecological risk, highlighting potential food safety concerns. Overall, MP accumulation and migration in Ph. violascens systems are jointly shaped by urban–rural gradients and mulching duration, with implications for belowground processes and the safety of edible bamboo shoots.

Accumulation characteristics and ecological risk evaluation of microplastics in sediment cores from the artificial reef area and surrounding seas of Haizhou Bay, north China

Characterization and risk assessment of microplastics in laver from the Yueqing Bay

Multidimensional characterization of microplastic pollution in subtropical urban soils: Combining geospatial analysis and polymer risk indexing.

Land use-based characterization and source apportionment of microplastics in urban storm runoffs in a tropical region

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.

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

Estuarine habitats are a critical zone of the Earth with strong land-sea interactions, that are strongly influenced by human activities. Microplastics (MPs) pollution in the Yellow River Delta (YRD) wetland, a typical young warm-temperate estuarine wetland, has not been comprehensively studied. The morphology, abundance, particle size, and polymer composition of MPs in the surface sediments of the YRD wetland were determined, and the pollution status and ecological risk in the study area were evaluated using the pollution load index (PLI) and potential pollution risk index (PRI). The results showed that the abundance of MPs in the YRD wetland was 20-520 n·kg-1, with a median value of 150 n·kg-1. The MPs were primarily fibers in shape and black in color, with particle size over 1 mm. The polymer components were primarily rayon, polyethylene, polyester, and polyethylene terephthalate. The PLI and PRI values of the MPs in the area were between 0.04-0.96 and 0.00-171.60, respectively, indicating that the pollution of MPs in the YRD wetland was at a slightly polluted level with low ecological risk.

Wastewater treatment plants (WWTPs) are one of the major collection points of microplastics (MPs). The MPs in influents and effluents of WWTPs were assessed for three cities on the southern coast of the Caspian Sea in the winter and spring seasons. The MP removal rate of WWTPs ranged between 71.12 and 88.13% depending on the season and treatment methods. The higher removal efficiency of MPs in the city of Sari compared to that in the other two cities might be attributed to the implementation of more effective treatment techniques at the Sari WWTP. Our findings showed that the presence of MPs in influents was greater in the spring than in the winter, attributed to the increased usage of personal care and washing products during the COVID-19 lockdown period. Conversely, in effluents, the abundance of MPs was higher in the winter than in the spring, likely due to precipitation and inadequate management of sewage overflows. On average, more than 50% of identified MPs had black/grey and white/transparent colours. The majority of the identified MPs that were found in both the influents and effluents of all three investigated WWTPs were smaller than 500µm and had a fibre shape. Our findings indicate that removing plastics with a size smaller than 100µm is more challenging compared to larger-sized plastics in WWTPs. Moreover, a strong correlation was observed between TSS and the abundance of MPs in influents. The predominant types of MP that were identified with spectroscopic analysis in most samples were polyamide (PA), acrylic, polyethylene (PE), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), and polypropylene (PP). Based on the results of our study, it can be estimated that a total of 132 × 106 and 223 × 106 MPs are discharged per day from the three investigated WWTPs into aquatic environments that ultimately reach the Caspian Sea in the spring and winter, respectively. Our findings enhance our knowledge about the load of MPs from WWTPs into the Caspian Sea, and it provides a foundation for future discussions on management strategies and the reuse of wastewater.

Effects of land use on the distribution of soil microplastics in the Lihe River watershed, China

Microplastics accumulation on beaches raises a serious concern worldwide. Hence, the present study was conducted with the focus of investigating the abundance, characteristics, risk assessment, surface morphology and elemental composition of microplastics (MPs) in the beach sediments of the Thoothukudi region, situated on the south-east coast of India, Gulf of Mannar region. The MPs abundance ranged between 19 ± 18.62 and 78.55 ± 95.17 items/kg with a mean abundance of 33.82 ± 26.11 items/kg and the spatial distribution of MPs showed insignificant variation. Fragments (59.48%), 0.5-1mm (43.66%) and blue-coloured MPs (45.61%) were highly predominant in the sediments. Attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy showed the dominance of polyethylene polymers in sediments (52.26%) and their sources could be attributed to the direct inflow of sewage, recreational and fishing activities and accidental loss. The current study revealed that microplastics (< 5mm) are ubiquitous along the Thoothukudi coast, posing a serious threat to the marine environment and marine organisms. The ecological risk assessment of MPs in sediments was calculated by adopting 3 models: the polymer hazard index (PHI), pollution load index (PLI) and potential ecological risk assessment (RI). The overall PHIsediments = 698.96 exhibited a hazard level of IV, which was mainly due to the varying abundance of polymer composition in sediments. The value of PLIsediments is 2.51, which mainly depends on the MPs abundance in sediments and yields the hazard level of I. The ecological risk posed by MPs in beach sediments along the Thoothukudi coast (RIsediments = 241.06) falls into the medium category, indicating that steps must be taken to reduce the flow of plastics through management measures such as proper wastewater treatment practices, recycling of plastic waste and proper waste disposal. Field emission scanning electron microscopy (FESEM) images revealed that MPs surfaces were strongly weathered and energy dispersive X-ray (EDX) spectroscopy spectra showed that the presence of inorganic elements associated with the surface MPs might be derived from the surrounding environment or additives in plastics. Hence, further research has to be conducted in view of studying the combined effects of MPs pollution and organic pollutants, which will provide further understanding of the contamination of MPs in the marine environment.

Microplastics (MPs) are a growing issue because they endanger both aquatic organisms and humans. Studies have indicated that wastewater treatment plants (WWTPs) are one of the major contributors to MPs in the environment. However, studies on the abundance of MP contamination in WWTPs and its transmission into aquatic organisms are still scarce, especially in Egypt. The goal of this study was to examine the temporal fluctuations in the distribution of MPs in surface water and the dominant macroinvertebrate fauna (Culex sp. larvae) in a fixed wastewater basin in Sohag Governorate, Egypt. The average of MPs in the surface water was 3.01 ±0.9 particles/L. The results indicated to seasonal variation of MP abundance in the wastewater basin that was significantly higher in winter than in the other seasons. The risk index for polymers (H), pollution load index (PLI), and potential ecological risk index (RI) were used to assess the degree of MP contamination. The basin has moderate H values (<1000) because of the presence of polymers with moderate hazard scores such as polyester (PES), polyethylene (PE), and polypropylene (PP). According to the PLI values, surface water is extremely contaminated with MPs (PLI: 88 to 120). The RI values of surface water showed higher ecological risk (level V). MPs in Culex sp. larvae were seasonally changed with an 85% detection rate, and an abundance average of 0.24 ±0.65 particles/ind, MP concentration in Culex sp. larvae was influenced by the MP characters (shape, color, and polymer). The larvae of Culex sp. showed a greater preference for black and red fibrous polyester (PES) with sizes (<1000 μm) of MPs. These findings suggest that Culex sp. larvae prefer ingesting MPs that resemble their food. It is possible to overestimate Culex sp.'s preference for lower sizes because of their catabolism of MPs. To better understand the preferences of Culex sp. larvae for MPs, further controlled trials should be conducted. PRACTITIONER POINTS: Wastewater is highly contaminated with microplastics (MPs) in the different seasons. First report of detection of the seasonal abundance of MP in Culex sp. larvae. Culex sp. larvae showed a stronger feeding preference for MPs with specific characteristics. Smaller size and blue polyester fibers were the dominant characteristics of MPs in wastewater.