Abundance and distribution of microplastics in water and sediment of Baiyangdian Lake, Northern China

Abstract Microplastics (MPs) have been found in all environment matrices and have become an issue of concern worldwide. In this study, Baiyangdian Lake in Northern China was investigated for the presence of MPs (0.45 µm–5 mm) in sediment and at different water depths. MPs were found at 1,000–20,000 pieces/m 3 (average 9,595) in water and at 400–2,200 pieces/kg (average 1,023) in sediment. Since the implementation of pollution abatement measures, visible MPs have been nearly eliminated; the MPs found in this study were mainly in the micrometer range, with no more than 3–5 pieces greater than 1 mm per sample. The main forms of MPs were fibrous and fragmented, and the main components were polyamide, polyethylene, and polypropylene. MPs found in water near a garbage transfer station showed the following abundance of MPs: surface water < middle water < bottom water. The sediment contained a higher amount of MP fragments, indicating that the historical transfer and disposal of garbage was a main source of plastic deposition in this area. There was a high content of fibrous MPs in surface water, while the abundance of fragmented MPs increased with the depth of water. The main sources of MPs in the study area were residential activities, local plastic factories, and the treated effluent from a sewage treatment plant.