Higher Microplastic Abundance Research Articles

Spatiotemporal dynamics and tidal transport of microplastics in the tropical waters of the Gulf of Thailand

Microplastics (MPs) contamination was investigated along a freshwater-seawater continuum from Chumphon River to the Gulf of Thailand. The vertical distribution in the water column and contamination in green mussels were also studied. MPs were detected in all water samples and sediment samples. Furthermore, MPs were detected in 75% of the green mussels. A higher abundance of MPs was observed in the river system than in the coastal region, indicating that river runoff associated with inland human activities is the major sources of MPs in the coastal regions and cultured green mussels. In the water column, a polymer gradient varying with depth existed where low-density particles decreased from surface to subsurface and sediment while high-density particles exhibited the opposite pattern. Polymers in surface and subsurface water were predominantly composed of low-density polyethylene, polypropylene, and polystyrene particles. However, sediment samples were equally dominated by those mentioned low-density polymers and high-density polyethylene terephthalate, polyamide, rayon, and cotton particles. Furthermore, fibers were the most common shape found in water, sediment, and mussel samples representing 95% of all particles in river water samples and were evenly distributed throughout the water column regardless of density. However, only shorter fiber (mostly <1 mm) was detected in green mussel samples similar to their living environment. Blue, black and white particles dominated all samples. During the tidal cycle, half of the MPs entering the Gulf of Thailand returned to the river during high tide. This backflow predominantly comprised small fibers and low-density polymer MPs. The average daily load of MPs from Chumphon River to the Gulf of Thailand was 3.33 × 102 million items/day.

Types and Abundance of Microplastics in Seawater and Sediment at Padang Beach Tourism Area, West Sumatra, Indonesia

The Padang Beach Tourism Area is a popular destination in Padang City making it susceptible to contamination by microplastics. From April to June 2023, we sampled seawater and sediment for microplastics from eight stations having varying degrees of human influence, including densely populated areas, river estuaries, tourist areas, and sparsely populated areas. We analyzed the samples to determine abundance, shape, size, color, and composition. Five shapes (fibers, films, fragments, granules, and pellets), seven colors (black, blue, brown, red, transparent, green, and white), and eight compositons (polycarbonate, polypropylene, polyethylene, polysulfone, polyvinyl chloride, polyethylene terephthalate, polystyrene, and polytetrafluoroethylene) were identified and categorized into five size ranges (1-100 µm, 100-300 µm, 300-500 µm, 500-1000 µm, and 1-5 mm). Microplastics abundance in seawater was not significantly different across stations, ranging from 0.064 to 0.229 particles/m3. Microplastic abundance in sediment, was also not significantly different across stations, ranging from 0.151 to 0.387 particles/kg. However, there was a significant difference between the abundance of microplastics in seawater and sediment. The highest abundance of microplastics was in the form of fragments, and there was significant difference from fiber, fragment, pellet, and granule types. In contrast, thre was a significant difference between the abundance of film-type microplastics in seawater and sediment. Overall, microplastic abundance was similar across densely populated areas, river estuaries, and tourist areas and higher than in sparsely populated areas.

Microplastics in fish species from the eastern Guangdong: Implications to Indo-Pacific humpback dolphin (Sousa chinensis) and human health

Microplastic (MP) pollution is widespread in aquatic environments, accumulating in organisms and transferring through the food web. This study investigated MP abundance, composition, and distribution in 15 fish species from eastern Guangdong, 11 of which are prey for Indo-Pacific humpback dolphins (Sousa chinensis). Results indicated the highest MP abundance in fish gastrointestinal tracts, with pelagic species being the most affected. Ethylene vinyl acetate (EVA) and polyethylene (PE), linked to local industrial activities, were the most prevalent polymers. Risk quotients (RQ) at 95th percentile for Indo-Pacific humpback dolphins exceeded one, suggesting significant MP exposure risk via prey ingestion. In contrast, the MPs risk for humans through fish consumption was minimal. These findings underscore the urgent need for improved plastic waste management to protect marine apex predators.

Microplastics contamination in three species of marine fish harvested by coastal land trawl in Banda Aceh City and Aceh Besar Regency waters, Indonesia

&lt;p style="text-align:justify;"&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;Banda Aceh City and Aceh Besar Regency are two of the areas experiencing rapid population growth and increased waste production, including plastics. The areas are directly adjacent to the coast, and the generated plastic waste has the potential to pollute the sea and fish. Therefore, this research aimed to analyze microplastics contamination in three species of marine fish caught in the coastal areas of Banda Aceh and Aceh Besar. The sampling was carried out for 3 months from January to March 2024 at three locations, namely Gampong Jawa (Station 1), Alue Naga (Station 2), and Krueng Raya (Station 3). The fish samples were ponyfish (&lt;/span&gt;&lt;em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;Leiognathus equulus&lt;/span&gt;&lt;/em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;), rabbitfish (&lt;/span&gt;&lt;em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;Siganus canaliculatus&lt;/span&gt;&lt;/em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;), and sardine fish (&lt;/span&gt;&lt;em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;Sardinella gibbosa&lt;/span&gt;&lt;/em&gt;&lt;span style="color:black;font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12pt;line-height:150%;"&gt;). The results showed that there were four forms of microplastics, namely fibers, fragments, films, and pellets, with seven types of colors, including black, brown, clear, blue, red, yellow, and green. The dominant shape and color were fragment and black, respectively. In ponyfish, the highest and lowest number of microplastic particles were found in samples caught in Alue Naga waters (4.51 particles/fish) and Krueng Raya waters (2.80 particles/fish). Meanwhile, rabbitfish had the highest and lowest abundance in Alue Naga waters (3.60 particles/fish) and Gampong Jawa waters (2.83 particles/fish), respectively. The highest and lowest abundance of sardine fish was found in Gampong Jawa waters (3.77 particles/fish) and Krueng Raya waters (1.50 particles/fish), respectively. In general, ponny fish had a higher abundance of microplastics than the other two species, and microplastics were highest in fish from the Alue Naga station based on location. According to Fourier Transform Infrared Spectroscopy (FTIR) test on flesh samples of the species, three types of polymers were detected, namely latex, nylon, and polypropylene. In this context, the species analyzed were contaminated with microplastics and unsafe for consumption.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;nbsp;&lt;/p&gt;

Assessment of microplastic exposure in nasal lavage fluid and the influence of face masks

Microplastics (MPs) can enter the human body through respiration and pose a hazard to human health. Wearing masks has become a routine behavior during the COVID-19 pandemic. The level of respirational exposure and the influence of wearing masks are currently unknown. We recruited 113 college students and divided them into natural exposure (NE), surgical mask (SM), and cotton mask (CM) groups. Nasal lavage fluid (NLF) was collected and MPs characteristics were analyzed using polarized light microscopy and laser direct infrared system. We found a relatively high abundance of MPs in NLF in the SM group (41.24 ± 1.73 particles/g). The particle size distribution and fibrous MP percentage significantly differed among the three groups. The main components in the NE, SM, and CM groups were polypropylene (58.70 %)，polycarbonate (PC, 49.49 %)，and PC (54.29 %). Components such as polyamide, polyethylene and polyethylene terephthalate were also detected. Wearing surgical masks increased the MP abundance in NLF (β = 0.36, P < 0.01). As the wear time increased, the abundance of MPs also rose (β = 0.28, P < 0.05). However, those who used bedding containing synthetic fibers had lower MP abundance in their NLF. This study highlights the use of NLF to evaluate MP exposure, which is associated with potential health risks.

Decadal changes in microplastic accumulation in freshwater sediments: Evaluating influencing factors

Microplastics are small plastic particles with sizes ranging between 1 μm and 5 mm. Microplastics can originate from macro plastics and degrade to a smaller size or be produced directly by manufacturers. Few studies have examined microplastic contamination in freshwater sediment cores to estimate changes in microplastic contamination over time. We present the results of a study that examined sediment cores from four watersheds, Kiskiminetas River, Blacklick Creek, Raystown Lake, and Darby Creek, in Pennsylvania, USA to reveal the history of microplastic accumulation and factors that contribute to microplastic distribution. The abundance and morphology of microplastics varied over time and between these four locations. The highest microplastic abundance was found in Raystown Lake, ranging from 704 to 5397 particles kg−1 with fiber as the dominant microplastic type, while Darby Creek (0–3000 particles kg−1), Kiskiminetas River (0–448 particles kg−1), and Blacklick Creek (0–156 particles kg−1) had lower microplastic concentration. Moreover, Darby Creek had the most diverse microplastic morphology and a trend of decreasing concentration with depth. Although the Darby Creek watershed has the most developed area and highest population density, it did not have the highest microplastic concentration. Averaged over the four cores, microplastic abundance increased as global plastics production increased from the 1950s–2010s. Our findings provide insights into the fate and transport of microplastic contamination in freshwater environments, which is vital to establishing sustainable mitigation strategies.

Microplastics in surface seawater of Kongsfjorden, Svalbard, Arctic

Microplastics have now become an emerging contaminant with high concern in the Arctic and Sub-Arctic Region. Here, the Kongsfjorden system in the Arctic has been investigated for abundance, distribution, and characteristic of microplastics in surface seawater. Eighteen samples were collected using an in-situ filtration sampling method, and then analyzed by Fourier-transform infrared spectroscopy. The average abundance of microplastics in surface seawater was 3.6 items m−3, with an abundance range of 0.0—10.0 items m−3. The highest abundance of microplastics was located adjacent to the eddy in Kongsfjorden, where a microplastic accumulation zone might have formed. Microplastics transported by ocean currents and those from local discharges might converge in this zone. Two sampling stations were set up at the wastewater treatment plant outfall, which showed an abundance range of 4.0—6.0 items m−3, slightly higher than the average abundance. Of the six polymer types identified, rayon, polyester and polyamide were the most common composition. Proportions in fiber form in surface water was 84.6 %, and blue (28.2 %) and transparent (25.6 %) were predominant colors. Most microplastics (>90.0 %) were less than 1 mm in the longest dimension. This study provided important baseline data as well as a practical microplastic sampling method for polar marine environments.

Evaluating the sources of microplastic contamination and quantifying its abundance in the Balu River, Dhaka, Bangladesh.

Microplastics (MPs) are prevalent environmental pollutants due to their durable composition, extensive use, and improper disposal. Despite their widespread presence, rivers have received less attention in microplastic research than other water bodies. This study focused on investigating the origins, prevalence, spatial distribution, and physicochemical characteristics of microplastics in the surface waters of the Balu River, located in Dhaka, Bangladesh. Surface water samples were collected at six sampling sites of Balu River (each about 1-5km apart) adjacent to the footwear industry, jute factory, textile mill, paper mill, agro and beverage factory, and cement plant. The study found that the average concentration of microplastics in the sampled water bodies was 102.5 ± 12.83 (items/l). Samples near the textile mill had the highest microplastic abundance (122 ± 18 items/l), while the cement plant had the lowest (58.5 ± 8 items/l). Analysis using a stereomicroscope revealed that fibers (29%), microplastics smaller than 100µm (45%), and transparent microplastics (19%) were the most prevalent types observed in terms of shape, size, and color, respectively. Furthermore, scanning electron microscopy (SEM) observation suggested the potential for additional degradation of these microplastics into smaller particles, potentially reaching the nanoplastic scale. Additionally, Fourier transform infrared (FTIR) analysis identified 07 distinct polymer types among the microplastics: nylon (24%), polyvinyl chloride (19%), high-density polyethylene (17%), low-density polyethylene (14%), polystyrene (12%), polypropylene (7%), and nitrile (7%). The findings of this study serve as a crucial indicator of microplastic contamination, providing valuable insights into the sources and magnitude of microplastic pollution within the significant freshwater ecosystem of Balu River, Bangladesh, particularly focusing on its river systems.

Microplastics in the commercially available branded milk in Bangladesh: An emerging threat for human health

Microplastics (MPs) are polymer-based particles commonly found in diverse foods that pose serious human health impacts throughout the food chain. Assessment of MPs in different food products is a prime measure to combat MP-related food contamination. Therefore, this study first investigated the identification, characterization, and potential risks of MPs in the commercially available milk brands (19 dry powders and 06 liquid brands) in Bangladesh. The presence of MPs in milk samples was 279.47 ± 134.26 particles/kg and 182.27 ± 55.13 particles/L for powder and liquid milk, respectively, with a significant variety. Study findings displayed miscellaneous colors, fiber shapes (powder=78 %; liquid=81 %), > 0.1 mm sizes (powder=69 %; liquid=65 %), and polyethylene (powder=48 %; liquid=44 %) dominating MPs categories. The pollution load index indicated significant pollution due to the high abundance of MPs. Further, other risk-evaluating indices including contamination factor and Nemerow pollution index represent moderate to high MP-induced pollution for both milk samples. Low to moderate polymeric risks are exhibited by powder and liquid milk samples. Children could be exposed to 3.43 times higher MPs than adults through daily oral ingestion, which has significant health effects. This study found that powder milk was the most severely MPs induced risk than liquid milk. Consequently, this study finding established a reference point for MP contamination in milk, so special attention must be taken during production, storage, and packaging stages to reduce MP contamination.

Appraisal of microplastic pollution and its related risks for urban indoor environment in Bangladesh using machine learning and diverse risk evolution indices

The widespread presence of Microplastics (MPs) is increasing in the indoor environment due to increasing annual plastic usage, which is becoming a global threat to human health. Therefore, this is the first research in Bangladesh to identify, and characterize, MP pollution and its allied threats to human health in the indoor urban environment, where 80 household dust samples were collected from the whole study area. The presence of MPs in household dust of the urban indoor environment was 25.8 ± 6.43 particles/g with a significant variety, whereas the fiber shape (73%), 0.5–1.00 mm ranged MPs size (58%), blue color (21%), and polystyrene polymer (34%) was the most ubiquitous MPs category. The pollution load index (1.61–2.96) indicated significant pollution due to the high abundance of MPs. Besides, other risks evaluating indices including contamination factor (1.00–3.51), and Nemerow pollution index (1.60–3.51) represent moderate to high MP-induced pollution. The polymer hazard index (119.54 ± 70.34) indicated significant risks for the selected polymers to the indoor environment living inhabitants. Machine learning approaches, especially random forest and support random vector machine were effective in predicting the number of MPs, where EC, salinity, pH, OC, and texture classes acted as controlling factors. Children and adults might be ingesting 4.12 ± 1.01 and 2.27 ± 0.57 particles/day through the ingestion exposure route, which has significant health effects. Polymer-associated lifetime cancer risk assessment results show that there are moderate risks for both adults and children, but children tend to be more susceptible to MP risks. The overall study found that Dhaka was the most severely MPs induced risky division among the others. This study reveals that high quantities of MPs in indoor environments could pose a serious health hazard' to different exposure groups.

Occurrence and Risk Assessment of Microplastics in the Coastal Seawater of Guangdong Province

Microplastics （MPs） are ubiquitous in the marine environment and have become an emerging pollutant that is attracting great attention. To reveal the pollution characteristics of MPs in surface seawater of coastal waters in Guangdong Province, nine bays （estuaries） were selected from Jiangmen to Shantou. The distribution and compositional characteristics of MPs were investigated through field sampling, oxidation digestion, and visual and compositional identification, and their potential sources were analyzed. The ecological risks were assessed by combining the pollution load index and the polymer risk index. The results showed that MPs were detected in all 30 surface seawater samples from the coastal waters of Guangdong Province, with an abundance range of 70-920 n·m-3 and an average abundance of （295.3 ±175.3） n·m-3. The highest MPs abundance was found in the Pearl River estuary, and the lowest abundance was found in Shenquan bay. The distribution patterns were mainly influenced by human activities and ocean currents. The dominant polymer types included polypropylene （31.2%）, phenol resin （16.0%）, polyethylene terephthalate （15.3%）, and polyethylene （10.9%）. The main shape, color, and size categories of MPs were fiber （57.5%）, transparent （72.0%）, and 0.5-1 mm （32.8%）, respectively. The possible sources of MPs mainly included aquaculture, fishing, navigation, tourism, municipal sewage discharge, and ocean current transportation. The model assessment results showed that the pollution load risk of MPs was relatively low, but the polymer risk was at a medium-high level. This study provides a data basis for the action plan of plastic pollution control in Guangdong Province and supports the prevention and control of marine MPs pollution.

Microplastics and their interaction with microorganisms in Bosten Lake sediment

Microplastics (MPs), discovered in oceans, lakes, and rivers, can infiltrate the food chain through ingestion by organisms, potentially posing health risks. Our research is the first to study the composition and distribution of MPs in Bosten Lake's sediment. In May, the average abundance of MPs was 0.95±0.72 particles per 10 gs, and in October, it was 0.90±0.61 particles per 10 gs. Bohu Town had the highest MP abundance, with 1.75±0.35 particles per 10 gs in spring and 2 ± 0 particles per 10 gs in autumn. In May, 53 % of the MPs were transparent, while in October, black MPs constituted 58 %. The predominant morphology was fibrous, accounting for 61 % of the total. MPs in the size range of 0.2–1 mm made up 91 % and 66 % of the total in May and October, respectively. The most common types of MPs in May were polyethylene terephthalate (PET) at 40 % and polyethylene (PE) at 26 %. In October, PET was the most prevalent at 71 %, followed by poly(ether-ether-ketone)(PEEK) at 11 %. Certain microbial taxa, such as Actinobacteriota, Pseudomonas, and Vicinamibacteraceae, associated with MP degradation or complex carbon chain breakdown, were notably enriched in sediment areas with high MP concentrations. A significant positive correlation was observed between the abundance of MPs in sediments and Actinobacteriota. Additionally, the abundance of Thiobacillus, Ca.competibacter, and other bacteria involved in soil element cycling showed a significant positive correlation with the organic matter content in the sediments. Anaerobic bacteria like Thermoanaerobacterium displayed a significant positive correlation with water depth. Our study reveals the presence, composition, and distribution of MPs in Bosten Lake's sediments, shedding light on their potential ecological impact.

Microplastic pollutants in sediments from a water supply reservoir: Spatial heterogeneity in abundance, characteristics and pollution evaluation

When assessing microplastics (MPs) in freshwater ecosystems, previous studies have primarily focused on natural rivers and lakes, with limited attention to urban water source areas. Sediments, recording the steady process of MPs accumulation during a long period of time, can act as an important sink for MPs. In this study, we investigated the distribution, characteristics and pollution evaluation of MP contaminants in sediments of a water supply reservoir of Hefei City (the Dafangying Reservoir). Meanwhile, the differences of MP concentrations in sediments in rural and urban areas were also compared. Our results detected five shapes, seven colors and six polymer types of MPs in sediments of the Dafangying Reservoir. Polystyrene, polyethylene and polypropylene were the most abundance types of MPs identified. The average MPs abundance of sediments in rural areas was 83.20 ± 32.99 n/100 g dry weight (d.w.), and 182.67 ± 72.21 n/100 g (d.w.) in urban areas. The total MP concentrations were significantly higher in sediments of urban sites than that in rural sites, which can be ascribed to more complex and diverse MP sources triggered by intensive anthropogenic activity in cities. Specifically, we also demonstrated significantly higher microbead abundance in urban sites, which may result from the widespread use of microbead in personal care products. Given the complexity and diversity of MPs in urban areas, we exhibited a relatively higher abundance of MPs in the Dafangying Reservoir than that in other rural larger reservoirs. According to the index of geoaccumulation, the sedimentary MPs were assessed as moderately polluted. Our study enriches valuable data on the distribution of MPs contaminants in water supply reservoir, and provides theoretical references for MPs control and management in reservoir ecosystems.

The Abundance of Microplastics in Sediment Siak River Pekanbaru City

Sediments are temporary and long-term reservoirs for waste including microplastic particles. Microplastics are large-sized plastics that are under 5mm in size. microplastic particles with a density greater than water can enter the sediment and accumulate. High water utilization activities can be a way for plastic waste from land to enter the waters, one of the rivers that has high utilization is the Siak River in Pekanbaru city. This study aims to analyze the abundance and distribution of microplastics based on 3 (three) stations in the Siak River. The research procedure consists of sampling, microplastic separation, and microplastic analysis. The results showed that the Siak River in Pekanbaru city contained microplastic types of fragments (32%), films (31%), fibers (25%), and granules (12%). The highest abundance of microplastics was at station 1 with an average abundance of 32.67/kg which was dominated by fragment-type microplastics. The Siak River in Pekanbaru city has been contaminated with microplastics which can be intentionally or unintentionally eaten by aquatic biota.

Microplastic Pollution and Risk Assessment in Packaged Teas in Türkiye

This article presents the first-ever findings on the release of MPs (microplastics) from tea bags containing tea leaves into tea infusions in Türkiye. The study aimed to investigate the possible distribution and abundance of MPs in cup of tea bags and teapot tea bags of fifteen packaged tea brands in Türkiye using ATF/FTIR analysis. The results showed that MPs were found in all the analyzed tea brands. Surprisingly, the highest particle number was observed in the dry tea samples (removed from tea bags) belonging to all brands. Brands A and O had the highest abundance of MPs. All MP particles identified were fiber in shape, and four colors were identified, with a predominance of navy blue. Polyethylene terephthalate (PET) was the most abundant polymer type. The size of MPs varied from 33.65 μm to 1680.20 μm. The daily MP exposure by tea intake was analyzed for male and female groups, and the dietary exposure for males was greater than that for females. According to the MP contamination factor values, a wide variety of MP contamination levels were determined, with a predominance of significant and very high levels of contamination. The mean polymer risk index was determined to be 10.80, indicating a low level of risk. Additionally, this study also provides information on the potential health effects of these harmful MPs. Considering that consuming tea is a significant way for individuals to come into contact with MPs, tea prepared with tea leaves packaged in tea bags could potentially have adverse effects on the health of consumers.Graphical

Distribution characteristics and integrated ecological risks evaluation modelling of microplastics and heavy metals in geological high background soil

The microplastics (MPs), a novel pollutant, and heavy metals (HMs) significantly affect soil ecology. The study investigated HMs and MPs in Qianxi's high geological background soil, established a model for risk evaluation with MPs types and shapes, and proposed a two-dimensional comprehensive index model for MPs-HMs combined pollution and risk evaluation criterion. The results revealed a high soil Cd concentration, with a mean value of 0.38 mg·kg−1. Additionally, soils from soybean–wheat intercropping–potato–corn rotation (SWI-PCR) exhibited significantly higher concentrations of Hg, As, and Pb compared with those from soybean–wheat intercropping-corn rotation (SWI-CR). Moreover, the soil exhibited a high abundance of MPs (8667.66 ± 3864.26 items·kg−1), mainly characterized by PS and fiber. The mean of adjusted ecological risk index (ARI) for MPs in soil was 525.27, indicating a grade 3 risk. The two-dimensional combined index (TPI) was used to assess the ecological risk of MPs–HMs combined pollution, exhibiting an exceedance rate of 56 % with a mean of 445.07. The risk level of the combined pollution was graded as 6, indicating high risk. The microplastic risk evaluation model and the comprehensive evaluation method of combined pollution established in this study provide a reference for the future risk evaluation of multi-pollutant combined pollution.

Microplastic pollution in the Thumbprint emperor (Lethrinus harak) from Tanzanian coastal waters: Occurrence, abundance, characterization, and relevance as a monitoring species

In the present study we collected the Thumbprint emperor (Lethrinus harak) from seven landing sites from the coastal waters around Dar es Salaam and Zanzibar (Tanzania) to (i) quantify and characterize microplastics (MPs) in their digestive tracts and (ii) use previously assessed environmental levels in nearshore surface waters and seabed sediments to determine whether L. harak could be a relevant biomonitor for MP pollution in the region. L. harak (n=387) had an overall frequency of occurrence (FO%) of 48 % and displayed spatial variation between sites with Kunduchi (FO=66.7 %) and Mijimwena (FO=17.1 %) having the highest and lowest FO%, respectively. Fish from Mjimwema had a mean MP content of 0.17 ± 0.38 MPs individual-1 whilst fish from Kizimkazi had the highest MP abundance (1.75 ± 2.33 MPs individual-1). Fibers (overall 64.7 %, range across sites 48–86 %) and fragments (17.9 %, 5–25 %) were the most dominant MP types whilst black (46.9 %, 40–58 %) and blue (22.5%, 7–36 %) MPs were the most common colours. Fish length (ρ= -0.09, p=0.09) or weight (ρ=0.07, p=0.18) did not significantly correlate to MP abundance in fish (Spearman rank correlations). Neither MP occurrence nor abundance was linked to MP concentrations in either surface waters or seabed sediments (Spearman rank correlation), but MPs in the fish better reflected MPs in the sediment compared to surface water (two-way ANOVA on ranked data). Whilst L. harak presents as a promising candidate to monitor MP pollution along the East African coast due to its ecology, overall, it lacks reliability. Nonetheless, the present study fills important knowledge gaps both geographically on the East African Coast and with an underrepresented taxonomic family (Lethrinidae ‘Emporer fishes’).

Mangrove mud clam as an effective sentinel species for monitoring changes in coastal microplastic pollution

The worldwide mangrove shorelines are experiencing considerable contamination from microplastics (MPs). Finding an effective sentinel species in the mangrove ecosystem is crucial for early warning of ecological and human health risks posed by coastal microplastic pollution. This study collected 186 specimens of the widely distributed mangrove clam (Geloina expansa, Solander, 1786) from 18 stations along the Leizhou Peninsula, the largest mangrove coast in Southern China. This study discovered that mangrove mud clams accumulated a relatively high abundance of MPs (2.96 [1.61 – 6.03] items·g-1) in their soft tissue, wet weight, as compared to previously reported levels in bivalves. MPs abundance is significantly (p < 0.05 or 0.0001) influenced by coastal urban development, aquaculture, and shell size. Furthermore, the aggregated MPs exhibit a significantly high polymer risk index (Level III, H = 353.83). The estimated annual intake risk (EAI) from resident consumption, as calculated via a specific questionnaire survey, was at a moderate level (990 – 2475, items·g -1·Capita -1). However, the EAI based on suggested nutritional standards is very high, reaching 113,990 (79,298 − 148,681), items·g -1·Capita -1. We recommend utilizing the mangrove mud clam as sentinel species for the monitoring of MPs pollution changing across global coastlines.

Significant regional disparities in riverine microplastics

Research on riverine microplastics has gradually increased, highlighting an area for further exploration: the lack of extensive, large-scale regional variations analysis due to methodological and spatiotemporal limitations. Herein, we constructed and applied a comprehensive framework for synthesizing and analyzing literature data on riverine microplastics to enable comparative research on the regional variations on a large scale. Research results showed that in 76 rivers primarily located in Asia, Europe, and North America, the microplastic abundance of surface water in Asian rivers was three times higher than that in Euro-America rivers, while sediment in Euro-American rivers was five times more microplastics than Asia rivers, indicating significant regional variations (p < 0.001). Additionally, based on the income levels of countries, rivers in lower-middle and upper-middle income countries had significantly (p < 0.001) higher abundance of microplastics in surface water compared to high-income countries, while the opposite was true for sediment. This phenomenon was preliminarily attributed to varying levels of urbanization across countries. Our proposed framework for synthesizing and analyzing microplastic literature data provides a holistic understanding of microplastic disparities in the environment, and can facilitate broader discussions on management and mitigation strategies.

Tracing microplastic sources in urban water bodies combining their diversity, fragmentation and stability

Tracing the sources of microplastics (MPs) across various environmental media is currently facing significant challenges due to their complex transportable features. In this study, we conducted a comprehensive identification of MP sources in Beijing water bodies by combining MP diversity and the conditional fragmentation model, thoroughly considering local multiple sources. The resemblance in MP community compositions implied shared or similar sources in rivers and lakes, and the sources were assorted and equivalent based on the high diversity of MPs. The conditional fragmentation model can act as a proxy of fragmentation characteristics of MPs. According to the model, suburban sewage, soils, and dry and wet deposition constituted significant sources of MPs in the rivers and lakes of Beijing. The extremely high abundance of MPs (520,000 items·m−3) in suburban sewage also confirmed it as a potential source. For MPs with different polymer types and morphologies, non-fibrous polypropylene (PP) was primarily controlled by soils, whereas the contribution of sewage sludge to fibrous polyethylene terephthalate (PET) was notable. Our study provides insights for more accurate source apportionment and contributes to a better understanding of MP fate in urban environment.