546 / 2024-07-16 20:38:45

Transport and distribution of Microplastics in the hyporheic zone

Hyporheic exchange,Microplastics,Streambed,Retention

Subtheme 3: Eco-hydraulics and Environment > Topic 2: Water Eco-environment Monitoring and Simulation

In recent years, the presence and ecological hazards of microplastics in rivers have gained considerable attention. However, there is limited understanding of the transport mechanisms of microplastics in the hyporheic zone, as the cooperative interaction among river flow, sediment properties and microplastic characteristics is rarely considered. This study combines experiment and numerical simulation to investigate the influence of sediment and particle properties on the transport pathways, interface process, and retention distribution of microplastics in the hyporheic zone. The results indicate that the hyporheic exchange, settling, and retention are the important factors in the microplastics transport between overlying water and riverbed. The majority of microplastics are retained in the stoss side of the bedform. Microplastics with higher settling velocities (v_s) and retention coefficients (k) exhibit greater transport depth and retention amount. As v_s and k increase, the net interface flux towards the riverbed accelerates. This study contributes to an advancement in predicting the distribution of microplastics in the riverbeds, providing a scientific basis for the management of microplastic pollution in rivers.