Occurrence and characteristics of microplastics in fish of the Han River, South Korea: Factors affecting microplastic abundance in fish

This study examined the abundance of microplastics (MPs) in 106 fish from 22 species inhabiting three sites of the Han River, South Korea. In total, 1753 MPs from 106 fish samples were identified with an average abundance of 15.60 ± 13.45 MPs per individual fish (MPs indiv) in the North Han River, 16.35 ± 12.32 MPs indiv in the South Han River, and 20.14 ± 10.01 MPs indiv in downstream of the Han River, indicating that the fish in the downstream of the Han River was the most contaminated by MPs. The dominant size of MPs detected in fish ranged between 0.1 and 0.2 mm, and the most common polymer types found in fish were polypropylene (PP) (≥40%) and polyethylene (PE) (≥23%), followed by polytetrafluoroethylene (PTFE) (≥16%) at all sampling locations. A significant correlation was observed between the log-transformed number of MPs with log-transformed fish length (p < 0.01) and with log-transformed fish weight (p < 0.01). The Kruskal-Wallis test disclosed a significant difference in the number of MPs among the feeding habits (p < 0.01), indicating that omnivorous and insectivorous fish contained more MPs than carnivorous and herbivorous fish. In addition, fish habitat result showed that pelagic fish contained a higher level of MPs than demersal fish, but no significant differences in the number of MPs among fish habitats were observed (p > 0.05).