Impacts of microplastic contamination on the rheology properties of sediments in a eutrophic shallow lake

Microplastic (MP) contamination is a growing global concern, with lake sediments serving as a significant sink for MP due to both anthropogenic and natural activities. Given the increasing evidence of MP accumulation in sediments, it was crucial to assess their influence on sediment erosion resistance, which directly affected sediment resuspension. To fill this gap, this study focused on the effect of MP on the sediments rheological properties. After 60-day experiments, it was found that MP addition into sediments reduced sediment viscosity, yield stress, and flow point shear stress. Meanwhile, MPs also significantly altered sediment properties and extracellular polymer composition. MP addition reduced extracellular polymeric substances production and cation exchange capacity, which then worked together and led to a weak sediment structure. Seemingly, MPs changed fluid sediment characteristics and caused stronger fluidity under less shear force. Consequently, the accumulation of MP might facilitate the resuspension of sediments under smaller wind and wave disturbances. This study provided novel insights into the direct impact of MPs on sediment physical properties using rheology, thereby enhancing our understanding of the environmental behavior of MPs in lake ecosystems.