Microplastics in the Sediments: From Rivers to Lakes Investigated in the Biggest Freshwater Lake (Poyang Lake) Basin and Yangtze River in China

Abstract

In recent years, microplastic (MP) pollution is increasingly becoming a new environmental problem of global concern. Rivers and lakes are important transport channels for MPs entering the ocean, and their contribution to MP pollution can’t be ignored. In this chapter, the largest freshwater lake in China, the Poyang Lake, and its typical basin wetland areas are selected as the research areas. Wetland soils or sediment samples were collected; the types, particle size, abundance, distribution, and the main sources of MPs in these samples were investigated using the flotation separation and microscopic identification methods. The results show that foams (polystyrene), fibers (low-density polyethylene), debris, and films are found in the sediments of the typical wetlands; the debris-based MPs were the major and accounted for 50–70% of the total, followed by film MPs and fiber MPs, and foam MPs accounting for the lowest proportion. MPs with size less than 1 mm occupied the dominant percentage, accounting for more than 60% of the total MPs. The distribution of MPs in the sediments of the typical wetlands in the Poyang Lake is positively related to human activities; the differences of MP abundance among different regions are influenced by human activities, hydrological conditions, river inputting, etc. The composition of MPs among different regions is closely related to the lifestyle of people in the region and the physical and chemical properties of MPs. This chapter can further supplement the basic data of the research on MP pollution in freshwater wetlands, such as rivers and lakes in China, and provide a basis for further research on MP pollution and its ecological impact.