Microplastics pollution and risk assessment in water bodies of two nature reserves in Jilin Province: Correlation analysis with the degree of human activity

As a new type of environmental pollutant, microplastics (MPs) are widely present in freshwater systems. The ecological risks of MPs pollution in nature reserves and the correlation between human activities and the abundance of MPs are still unclear. This is the first survey of MPs in freshwater systems in Northeast China. The content and composition of MPs in 19 water samples were investigated in Chagan lake and Xianghai. The abundance of MPs samples in Chagan Lake averages 3.61 ± 2.23 particles/L, and in Xianghai averages 0.29 ± 0.11 particles/L. The main types of MPs in Chagan Lake are PA (23.7%) and PS (53.2%); while in Xianghai are PP (56%) and PS (32.7%). Foam, white and <1 mm are the main shapes, colors and sizes of Chagan Lake MPs, while of Xianghai are film, transparent and <1 mm. This may be related to the well-developed tourism and fishing industry (foam and fishing line) in Chagan Lake and aquaculture in Xianghai (foam and plastic film). The hazard index (HI) indicated a Hazard Level III for MPs pollution in Chagan Lake and Xianghai. Pollution load index (PLI) and potential ecological risk index (RI) indicate that the pollution risk of MPs polymers in the two places is relatively small. The degree of human activity is quantified to analyze the correlation of MPs abundance. The quantified scores are positively correlated with the abundance of MPs at different sampling points (Chagan lake: P < 0.05, 95% Cl; Xianghai: P < 0.05, 95% Cl).