Distribution characteristics and risk assessment of microplastics in Lake Bosten

As a widespread emerging pollutant, microplastics (MPs) have become one of the most significant threats to global ecosystems. Bosten Lake, the largest inland freshwater lake in China, represents a typical lake in an arid zone. To provide a theoretical basis for MPs pollution control in such regions, this study systematically investigated the characteristics, distribution, and ecological risks of MPs in Bosten Lake. Results show that MPs were widely present in the lake, with abundances in surface water ranging from 1.33 to 9.43 n/L (mean: 4.8 ± 1.78 n/L) and in sediments ranging from 151.55 to 953.31 n/kg dry weight (dw) (mean: 479.11 ± 210.22 n/kg), suggesting the presence of certain levels of pollution when compared to domestic and international studies. White (54.09 ± 5.14%) and black (30.07 ± 4.28%) MPs dominated, with fibers and fragments comprising over 70% of the forms. Polypropylene particles (0.1-0.5 mm) were the predominant type. Potential sources include residential activities, tourism, agriculture, and fisheries. Seasonal variations were observed in ecological risk, with the potential ecological risk index indicating an overall high-risk level. These findings highlight the need for dynamic management strategies for Bosten Lake and provide a scientific basis for monitoring MPs and assessing their ecological impacts in arid lake environments.