Spatial Distribution of Microplastics in Water and Sediments of Main Rivers in Taihu Lake Basin

Contemporary research on microplastic pollution has mainly focused on the ocean as a large sink, with a few studies involving relatively small sinks such as inland rivers and lakes. Taihu Lake is a typical inland lake and is the third largest freshwater lake in China. In this study, the spatial and temporal distribution, abundance, particle size, polymer composition, and ecological risk indices of microplastics in the water and sediments of 15 major inlet rivers in the Taihu Lake basin were investigated. The abundance of fibrous microplastics was the highest among the four characterized microplastic types. The particle size of microplastics in the water column and sediment was mainly in the range of 20–200 μm. The main component of microplastics in the water column was polyurethane, while in the sediment the main component of microplastics was polyurethane. Fibrous microplastics with a principal size of 20–100 μm are the main component of microplastics in landscape river sediments. The navigable rivers had the highest abundance of microplastics. All three river types have an environmental risk rating of III, which is at a medium to high level. The results of this study provide a reliable basis for the study of this sink in inland lakes.