Spatial Distribution and Characterization of Microplastics in the State Parks' Water Bodies within A Large-scale Watershed in the U.S.A.

Microplastics (MPs) are emerging pollutants, and they can absorb and transfer chemicals, which may cause significant effects on biota and risks to human health. State parks are natural areas highly influenced by seasonal tourist activities. This study investigated the distribution and characterization of MPs, including abundance, size, shape, and color, in seven Virginia State Parks within the James River Watershed (Douthat, Natural Bridge, Holliday Lake, James River, Powhatan, Pocahontas, and Chippokes Plantation State Parks). The MP concentration among the seven locations in the watershed had a significant difference (p < 0.05) and ranged from 0–26.5 particles/L with a mean of 8.33 ± 1.39 particles/L. The mountain region water bodies (Douthat and Natural Bridge) had the lowest MP concentration (< 4 particles/L), while the mainstream water bodies had a significantly higher MP concentration than other water bodies (10–20 particles/L) (p < 0.01). The size, shape, and color of MPs were also significantly different among all locations (p < 0.05). Faded and aged fragments with sizes below 1 mm were the most abundant, suggesting that terrestrial MPs were the most influencing source at most of the State Parks, and weathering effects have played a significant role in the fragmentation of plastics. In addition, a significantly positive relationship between MP concentration and the fraction of overnight guests was found (p < 0.0001). Our study indicated that State Parks and protected areas are polluted by MPs, which may pose potential harm to the surrounding environment, including both wildlife and humans. [ABSTRACT FROM AUTHOR]