Hydrodynamic driven microplastics in Dongting Lake, China: quantification of the flux and transportation

Hydrodynamic conditions have a significant effect on the fate of microplastics (MPs). Moreover, research on the relation between hydrodynamic conditions and MPs in freshwater environments is critical and unquantified. In this regard, herein, a methodological framework integrating system monitoring with numerical simulation has been developed and successfully implemented for Dongting Lake, a large freshwater lake fed by multiple rivers. According to time-series monitoring and hydrological data, 199.29/128.50 trillion MP items entered or exited Dongting Lake in 2021. In addition, a coupled numerical model identified four key areas of MP accumulation, which overlap with nature reserves and agricultural zones, posing considerable risks to the ecological gene pool and food security. The quantitative results obtained using the developed framework enable calculation of MP inflow and outflow fluxes and facilitate analysis of MP transportation. Overall, this study provides a scientific basis for preventing and controlling MP pollution in Dongting Lake and offers valuable insights for future research on related issues in freshwater ecosystems.