An examination of the occurrence and potential risks of microplastics across various shellfish

The ingestion of microplastics by shellfish pose a potential health risk for human via seafood consumption. This study investigated and compared the contamination levels and potential human health risks of microplastics in the digestive system of commercial shellfish from North (Qingdao) and South (Xiamen) China. Microplastics were detected in 70%-100% of shellfish samples from Qingdao and 70%-90% of shellfish samples from Xiamen, with abundances ranging from 1.2 to 4.1 items/individual (or 0.8-4.4 items/g, wet weight of digestive system) in shellfish from Qingdao and 1.3-6.0 items/individual (or 2.1-4.0 items/g) in shellfish from Xiamen. The microplastic composition was dominated by rayon and tended to be fibrous in shape, and white, black, and transparent in color. Microplastics <500 μm were the dominant size range, in which the size range of 100-200 μm was the most abundant size. Features of microplastics in the water-dwelling shellfish were different from those of the sediment-dwelling shellfish, and the microplastic features in the shellfish correlated with the sampling region, shellfish length, total wet body weight, and wet weight of the digestive system. Risk assessment results revealed that the potential human health risk posed by microplastics from the digestive system of commercial shellfish was higher in Qingdao than Xiamen.