Author(s): Wang Hua
Linked Author(s): wang hua
Keywords: Microplastics Transport and diffusion process Lake model Ecological risk
Abstract: Understanding the transport and diffusion process of microplastics (MPs) in lakes is of great significance to the cumulative assessment of controlling land-based MP pollution. The MPs in the surface water of Poyang Lake were identified from previous studies to be mainly composed of three representative particles: polyethylene (PE) fiber, polypropylene (PP) fragment and PE film, and this study explored the differences in the transport and diffusion of different types of MPs in three flow regimes in Poyang Lake by applying the Mike 21 model. The results show that MP particles migrate northward under the gravity flow and jacking flow regimes. The average time required for MPs to reach the northern lakes in jacking flow state was 21.29% shorter than that in gravity flow. Instead, MPs undergo reverse movement driven by back flow. Density and shape are the main factors affecting the transport and diffusion of MPs in lakes in the same flow regime. The average concentration of PE fiber in the lake area is 30.61% and 68.68% higher than both, PP fragment and PE film. In addition, MP particles tend to flow into the Yangtze River under the jacking flow; the accumulation hotspots of MPs in gravity flow and back flow are respectively in Poyang Lake National Nature Reserve and Nanji Wetland National Nature Reserve. In terms of ecological risks, the risk of the entire lake area assessed using the HI index is low, but the highest risk index used to assess accumulation hotspots using the PLI index has reached Level IV. This study provides reference and warning for tracking the paths and risks of land-based MPs entering freshwater lakes.
Year: 2025