Occurrence and Distribution of Microplastics in surface water and sediments of two typical estuaries in Bohai Bay, China
Estuaries are considered to be the seriously polluted area by microplastics in the environment. As the most important water body in North China, the pollution level of microplastics in two typical estuaries (Haihe Estuary (HHE) and Yondingxinhe Estuary (YDXE)) of Bohai Bay has not been well understood now. In this study, the occurrence and distribution of microplastics in both surface water and sediments of HHE and YDXE were investigated. The average concentrations of microplastics in the surface water samples were 1485.7 ± 819.9 items/m3 for HHE and 788.0 ± 464.2 items/m3 for YDXE, respectively, while the concentrations of microplastics in the sediments were 216.1 ± 92.1 items/kg dw for HHE and 85.0 ± 40.1 items/kg dw for YDXE, respectively. The concentrations of microplastics in surface water and sediment samples of HHE were both higher than those of YDXE, though YDXE is a typical sewage-received river. The anthropogenic activities and the river input were the main sources of microplastic pollution in estuarine areas. Meanwhile, the sewage river could be a point source of microplastic pollution in a small scale. Aside from the abundance of microplastics, the distribution and composition were also analyzed. The small size (particle diameter smaller than 1 mm) was dominant among different sizes of microplastics, the most abundant shape was fiber and the colored microplastics were widely found in YDXE and HHE. In this manuscript, we provided the detailed information on microplastics pollution to support the control and management in HHE and YDXE.