Spatiotemporal distribution, source identification and inventory of microplastics in surface sediments from Sanggou Bay, China

Abstract

Microplastic pollution has become a major global environmental issue. Yet the source identification and inventory of microplastics in mariculture areas remain unclear. Here we investigated the spatiotemporal distribution, source and inventory of microplastics in surface sediments from Sanggou Bay, China. The results showed that average abundance of microplastics in the surface sediments was 1674 ± 526 items/kg dry weight, which represented a heavy level when compared with other sea areas, including coastal waters, estuaries, the open sea and other mariculture areas. Microplastics with a size of <0.5 mm were dominant throughout four seasons. The dominant shape of microplastics was granule in summer, autumn and winter, and film in spring, respectively. The most common color of microplastics was transparent. Polyethylene was the dominant polymer in summer, autumn, and winter, while polystyrene accounted for the largest proportion in spring. Approximately 57.72% of the microplastics in surface sediments originated from the plastic mariculture facilities, suggesting that mariculture makes a significant contribution to microplastic pollution in Sanggou Bay. Estimated inventory of microplastics in surface sediments of Sanggou Bay was 183.73 tons. Our results improve the understanding of risks caused by mariculture-derived microplastics to marine ecosystem and human health.