Seasonal relevance of agricultural diffuse pollutant with microplastic in the bay

Microplastic particles between 10 μm and 1 mm in the marine environment have attracted international attention due to their potential health risk. Based on the current field investigations and source identification studies, the transport pattern from territorial to marine environments is comparatively unknown. Acetochlor concentrations and the microplastic abundance in the water, sediment and fish of Jiaozhou Bay in spring, summer and winter were measured. The seasonal relevance of the typical diffuse agricultural pollutant acetochlor with microplastics in river water and seawater in three zones (estuary, coastal and bay) were analyzed, which demonstrated the similar transport path and source from land to the bay. The electron microscopy and energy spectra of microplastics in three seasons highlight varied characteristics of microplastics during the transport. The spatial distribution of microplastic abundance in the sediment in the bay presented a decreasing pattern from the estuary to the coastal and bay waters. Microplastics were detected in all of the stomach samples in the bay with an abundance of 7.45-10.11 n/g. dw, which show the biological transport from bay. The analysis of microplastic size, shape, color and composition properties in the water and sediment further demonstrated the transport of microplastics in the bay.