Microplastics in the Coral Reef Systems from Xisha Islands of South China Sea.

The impacts of microplastics on coral reefs are gaining attention due to findings that microplastics affect coral health. This work investigated the distribution and characteristics of microplastics in the seawater, fish, and corals in 3 atolls from the Xisha Islands of South China Sea. In the seawater samples, microplastics were detected in the outer reef slopes, reef flats, and lagoons with abundances ranging from 0.2 to 11.2, 1.0 to 12.2, and 1.0 to 45.2 items L-1, respectively. Microplastic abundance was 0-12.0 items individual-1 (0-4.7 items g-1) in fish and 1.0-44.0 items individual-1(0.02-1.3 items g-1) in coral. The predominant shape and polymer of microplastics in seawater, fish, and coral were fibrous rayon and polyethylene terephthalate (PET). Microplastic sizes primarily ranged from 20-330 µm in both the seawater and fish, while there were relatively more 1-5 mm microplastics in the corals. The shape, size, color, and polymer type distribution patterns of microplastics in seawater more closely resembled those in fish gills than those in fish gastrointestinal tracts or coral samples. This study shows that microplastics are abundant in these coral reef systems and they are captured by fish or "trapped" by corals.

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.