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Microplastics have been widely detected in the natural water environment, which brings inevitable risks to the water ecosystem and human health. However, the understanding of the potential impact of microplastics on aquatic animals, plants, and human health is still limited, and technical methods to control microplastic pollution in natural water are still rare. Hence, this paper summarizes the progress of research on microplastic pollution in water systems in terms of microplastic source, attributes, distribution characteristics, environmental effects, and prevention and control methods according to the relevant research reports on water microplastic pollution. It also expounds the basic ways for the prevention, control, and treatment of water microplastics, and looks forward to the research direction of water microplastic pollution in the future. The results show that the abundance of fresh water microplastics in China is higher than that in other regions, but the pollution level of marine microplastics is at the middle level. Compared with other countries, the pollution degree of microplastics in aquatic organisms in China is at the middle and lower level, but the spatial heterogeneity is more obvious. Through hydraulic control and the substitution of degradable plastic products, water microplastic pollution can be greatly reduced. This paper can provide a reference basis for the formulation of microplastic pollution prevention and control in China. [ABSTRACT FROM AUTHOR]

• MPs were mainly fibrous, blue and in 20–500 μm in industrial mariculture. • Long operating time led to higher MP concentration in RAS. • Occurrence and distribution of MPs was analyzed in long & short operated RAS. • Microfilter removed MP in film, granule, fragment and those > 1000 μm efficiently. • PMF model was used to analyze the source of MP based on the polymer type. Industrial mariculture, a vital means of providing high quality protein to humans, is a potential source of microplastics (MPs) which have recently received increasing attention. This study investigated the occurrence and distribution of microplastics in feed, source water and recirculating aquaculture system (RAS) with long & short operating times as well as in fish from typical industrial mariculture farms in China. Results showed that microplastics occurred in all samples with the average concentration of 3.53 ± 1.39 particles/g, 0.70 ± 0.17 particles/L, 1.53 ± 0.21 particles/L and 2.21 ± 0.62 particles/individual for feed, source water, RAS and fish, respectively. Microplastics were mainly fiber in shape, blue in color and 20–500 μm in size. Compared with short operated RAS, long operating time led to higher microplastic concentration in RAS, especially that of microplastic in 20–500 μm, granular and blue. Regardless of short or long operating time, microplastics in RAS mainly gathered in culture tank, tank before microfilter and fixed-bed biological filter, and the microfilter removed efficiently the microplastic with the shape of film, granule, fragment as well as those with size > 1000 μm. As for the polymer types, polyamide (PA, 71.9 %) and polyethylene terephthalate (PET, 65.7 %) dominated in feed and source water, respectively, which may be the reason for the high proportion of PA (38.8 % and 26.4 %) and PET (31.8 % and 30.2 %) in RAS and fish. In addition, polypropylene (PP) was also detected in RAS (18.7 %) and fish (22.6 %), indicating that other plastic facilities such as PP brush carrier also made a contribution. Positive matrix factorization (PMF) model revealed three sources of MP in RAS, namely plastic facilities, industrial sewage and plastic packaging products. Our results provided a theoretical basis for the management of MP in RAS. [Display omitted] [ABSTRACT FROM AUTHOR]

Microplastic pollution has been widely studied in the marine environment, but is much less explored in terrestrial waters, notably in China. Therefore, we studied the degree of microplastic pollution in surface waters of Lake Ulansuhai, a major freshwater lake in the Yellow River basin of northern China. Results show microplastic concentrations ranging from 1760 ± 710 to 10,120 ± 4090 n/m3. The microplastic spatial distribution is heterogeneous, with higher levels near the drainage canal entrance of Lake Ulansuhai, and a downward trend from north to south in the lake. The main type of microplastics is colored particles, including fibers as the most abundant. More than 80% of microplastics were smaller than 2 mm. FTIR analysis results show that the main plastics were polyethylene, polystyrene and polybutylene terephthalate. There were also some metallic elements adsorbed on the surface of microplastics, such as Fe, Ca and Zn, detected by energy-dispersive spectrometry. The presence of metallic elements may worsen water pollution. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are emerging pollutants. Landfills store up to 42% of worldwide plastic waste and serve as an important source of MPs. However, the study of MPs distribution and the plastic biodegradation potential in landfills is limited. In this study, the distribution of abundance, size, morphology and polymer type of MPs and plastics biodegradation species in refuse samples along landfill depths were extensively investigated within a large-scale landfill in Shenzhen, China. In addition, plastics biodegradation enzymes were evaluated in seven Chinese large-scale landfills leachate. MPs distribution pattern was investigated in all refuse samples. The abundance of MPs in refuse samples varied between 81 and 133 items/g. The size of MPs in all samples varied between 0.03 and 5 mm, and the average sizes were 1.2 mm ± 0.1 mm. The main morphology and polymer type were fragments and cellophane, respectively. Landfill depth was significantly negatively correlated with the relative abundance of MPs size 1–5 mm (p < 0.05) and was positively correlated with the relative abundance of MPs size < 0.2 mm (p < 0.05), suggesting that plastics were broken down during municipal solid waste decomposition. The multiple regression on matrices analysis further showed the landfill depths and plastic morphology significantly impact the MPs distribution. The strains, Lysinibacillus massiliensis (with relative abundance of 1.8%) for low-density polyethylene and polystyrene biodegradation, and Pseudomonas stutzeri (0.1%) for low density polythene and polypropylene biodegradation, were detected on the plastic surface with high relative abundance. Furthermore, 75 plastic degradation species and their associated 31 enzymes (breakdown 24 plastics) were discovered in seven landfills leachate samples. [Display omitted] • The abundance of MPs in refuse samples ranged from 81 to 133 items/g. • Landfill depths was correlated with the relative abundance of MPs size (p < 0.05). • Depths and plastic morphology significantly impact the MPs distribution. • Typical plastic degradation strains were detected on the plastic surface. • 75 plastic degradation species and their associated 31 enzymes was discovered. [ABSTRACT FROM AUTHOR]

• Scavenging efficiency of rainfall for airborne MPs extended a period after the rain. • Contributions of airborne MPs to rivers could not be ignored. • Intercepting masses by trees only offset those loading into rivers. • Sparse and lowrise buildings are sensitive areas for airborne MPs. The issue of airborne microplastics (AMPs) pollution is receiving increasing attention, but effective solutions are still limited. In this study, AMPs were collected in pairs from an open space and under a tree (Ficus virens) in the suburb of Chengdu, southwest China, to investigate the current pollution status. The meteorological factors and underlying surface types were analyzed to investigate whether these factors could influence and mitigate the pollution of AMPs. The results showed that the fibrous AMPs accounted for the vast majority and the dominant polymers were polypropylene-polyethylene (PP-PE) and polypropylene (PP), with an average deposition flux of AMPs of 192 n/m2/d (22.41 µg/m2/d). Rainfall was found to have the prolonged scavenging efficiency for AMPs, which could extend to 8 to 48 hours after the end of rainfall, and this is a new insight into the relationship with meteorological factors. Interactions between the key underlying surface types and AMPs were also studied. The representative tree species (Ficus virens) had a low interception rate of 6.25% for AMPs and retained mainly small-sized AMPs and more fibers. The masses of AMPs loaded into Chengdu rivers could reach 1149 kg annually, with the unit mass load of 13.6 kg/km2 in urban rivers and 8.2 kg/km2 in suburban rivers. The masses intercepted by trees and bushes throughout the city only offset the masses loading in rivers, and open or sparse buildings were found to be sensitive areas for AMPs, which indicated the urgent need to control and mitigate the pollution of AMPs, especially in these sensitive areas. This work comprehensively analyzed the AMPs pollution from various perspectives and attempted to find ways to mitigate this pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

Freshwater rivers play the key role in providing drinking water sources and building the bridge of oceans and lands. Hence, environmental pollutants can be transferred into drinking water through a water treatment process and transported land-based microplastics into the ocean. Microplastics are considered a new pollutant that is becoming a threat to freshwater ecosystems. The present study investigated the temporal and spatial variation of microplastics abundance and their characteristics of occurrence in surface water, sediment and soil samples of Baotou section of Yellow River in China in March 2021 and September 2021. According to the LDIR analysis, the average abundances of microplastics in wet season (surface water 2510.83 ± 2971.27n/L, sediment 6166.67 ± 2914.56n/kg) were higher than that in dry season（surface water 432.5 ± 240.54n/L, sediment 3766.67 ± 1625.63n/kg), particularly being significant difference in the dry and wet seasons of surface water. The predominant polymer types in surface water (PBS and PET during the dry season, PP during the wet season) demonstrated that the temporal variation of microplastics abundance in surface water could be attributed to the combined effect of the regional precipitation, fishing activities and improper disposal of plastic waste. And the results of spatial abundances of microplastics showed that the microplastics abundance of soil and sediment was higher than that in river water and microplastics abundance in the river of the south side was the higher than other water sampling sites, revealing the differences of microplastics burden at the different sampling sites. Moreover, it is worth noting that a large amount of PAM was detected in sediments and soil, but not in water, and the biodegradable plastics PBS and PLA were also detected in the Yellow River. It was a very useful information for evaluating environmental impacts and ecological effects of degradable plastics compared to the traditional plastics after the implementation of a new environmental policy in the future. Thus, this study provided insights into the temporal-spatial characteristics of microplastics in an urban river and raised environmental management awareness of the long-term threat to drinking water safety by microplastics. [Display omitted] • The temporal and spatial changes of microplastics in Baotou section of Yellow River were reported for the first time. • The abundance of microplastics in water samples in the wet season was higher than that in the dry season. • The abundance of microplastics was higher in soil and sediment than in surface water. • The size of microplastics was mainly distributed in 20–50 μm in all samples. • The composition of microplastics showed spatiotemporal variation. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are a major global issue in the marine environment, and fish inhabiting coastal environments are susceptible to the ingestion of MPs. Knowledge regarding MPs in fish along the coast of China is very limited. In this study, the characteristics and retention of MPs in 19 fish species in the Yellow Sea were systematically studied. MPs were detected in all of the fish species sampled. Overall, 552 pieces of plastic were removed from a total of 1320 fish, including 546 pieces of MP （99%）(0.41 MP/fish) and 6 pieces of meso/macro-plastic (1%). Three MP types were found: fibers, pellets, and fragments, which accounted for 67%, 22%, and 11% of the total, respectively. MP length ranged from 16 to 4740 μm, with an average of 941 ± 43 μm. The average lengths of the fibers, pellets, and fragments were 1233 ± 57 μm, 263 ± 24 μm, and 503 ± 91 μm, respectively, and MP length was positively correlated with fish length. Fourteen polymers were detected, with organic oxidation polymers (40%) being most abundant, followed by polyethylene (22%) and polyamide (11%). The retention of MPs in fish was affected by sampling areas and fish weight. Fish collected from the area adjacent to the Bohai Sea and the Yangtze River Estuary were found to possess higher levels of MPs than those collected from the center of the Yellow Sea. The average number of MPs per fish (which ingested MPs) was negatively correlated with fish body weight. The retention of MPs may affect the quality and quantity of fishery resources in the Yellow Sea, especially the commercial fish. It is suggested that future studies be conducted to determine the ingestion rate, retention time, and egestion rate of MPs by fish to enable a rational risk assessment by combining the field results. [ABSTRACT FROM AUTHOR]