Microplastic occurrence in the northern South China Sea, A case for Pre and Post cyclone analysis

Microplastics (MPs) have become a great concern owing to their persistence and ecotoxicity in various envi-ronmental compartments. MPs can be transported from land to oceans via the aquatic system, and the oceans are believed to be the final sink for MPs. To resolve the lack of data concerning MP contamination in the northern South China Sea (NSCS), coastal seawater and sediments were investigated. The sample sites included the coastal area from Hong Kong to western Guangdong Province, which provided a representative coverage of variable distance to the shore. MP particles were observed in all samples, suggesting a widespread MP pollution in NSCS. The average MP abundance was relatively high in South China Sea, but it was lower than that in other Chinese coastal areas. In all samples, the dominant MP polymer was polyethylene terephthalate fibers. No statistically significant correlation was found between the abundances of MPs in seawater and sediment. The MP distribution in surface water affected by the monsoon exhibited high abundance in the east and low in the west, and MPs were more abundant near the shore than away from it. The tropical cyclone had no obvious effect on the overall MP abundance except in the Hong Kong west marine water (R4), which may attribute to proximity to Hong Kong and other islands.

Automated summary

Microplastics (MPs) have been found to be widely present in the northern South China Sea, with polyethylene terephthalate fibers being the dominant polymer. Although the abundance of MPs in the South China Sea is relatively high, it is lower compared to other Chinese coastal areas. There was no statistically significant correlation between the abundances of MPs in seawater and sediment, and the distribution of MPs in surface water influenced by monsoons showed higher abundance in the east and lower in the west.