Abstract: Dams have profound effects on the environmental behaviors of pollutants and hydrological processes of rivers. Microplastics are a type of emerging pollutants, which are widely distributed and difficult to be degraded. The retention of microplastics in the water body in front of dams may lead to ecological risks, which has received wide concerns. Here, we summarize the influence of river damming on the transportation of microplastics in the water system, the vertical and horizontal migration of microplastics in the reservoir, and the changes in the abundance and distribution patterns of microplastics during reservoir operations. To better understand the microplastic pollution in waters under the influence of dams, we further analyzed the effects of reservoir impoundment on the retention of microplastics, as well as the risks brought by the microplastics retained in the reservoir. This review would provide a theoretical basis for the prevention and control of possible microplastic pollution in the reservoir.

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