Microplastic pollution in the Maowei Sea, a typical mariculture bay of China

Abstract The ingestion of microplastics by organisms presents a potential exposure route for humans via seafood consumption. Although mariculture has become an essential source of seafood worldwide, the content of microplastics in the mariculture zone has received less scrutiny than in the wild environment. The Maowei Sea is a semi-closed bay that is rich in fishery resources. The specific levels of microplastics in the Maowei Sea and its fishery products remain undetermined. In this paper, we detail the distributions and characteristics of microplastics in the aquaculture water and biota of the Maowei Sea. Microplastics were detected in the range of 1.2–10.1 particles/L in Maowei Sea surface water, with high microplastic content in estuarine oyster nursery (10.1 particles/L) and Qinzhou harbor (8.8–9.5 particles/L) sites. In water samples from the three inflowing rivers, the abundances ranged from 2.9 to 4.5 particles/L, which is comparable to that in Maowei Sea surface water. Of 66 collected fish belonging to 12 species, microplastics were observed in all of the gastrointestinal tracts (GITs) and in the gills of 40 individuals. In the GIT and gill tests, the abundances of microplastics ranged from 2.0 to 14.0 and from 0.0 to 8.5 particles/individual, respectively. The enhanced particles/individual figures in the GIT relative to the gill are particularly noteworthy. Demersal species showed significantly higher abundances of microplastics than pelagic species ( p Capsule abstract Microplastics are widespread in the aquaculture water and biota in the Maowei Sea, a mariculture bay.