Pollution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Urban Rivers in a Northeastern Chinese City: Implications for Continuous Rainfall Events

Most studies have concentrated on the distribution of polycyclic aromatic hydrocarbons (PAHs) in air, water, and soil; however, little is known about their behavior during urban wet deposition. During frequent urban rainstorms, surface runoff carries large amounts of organic pollutants into water, which has a significant impact on the quality of the water environment. "Poseidon" made landfall in Jilin Province on 27 August, 3 September, and 7 September 2020, respectively, causing some impact on the surface water. Gas chromatography-mass spectrometry (GC-MS) was used to measure the concentrations of 16 major PAHs in stormwater and water samples from the Yitong River. The PAH concentrations in rainwater runoff gradually decreased with increasing rainfall duration. The PAHs in the Yitong River water samples were mainly composed of two to three rings, with total concentrations ranging 279.19-756.37 ng/L. Ratio characterization and principal component analysis of the sources of PAHs in the water samples revealed that some water bodies had also been contaminated by oil spills in addition to combustion emissions from coal and motor vehicle oil. Health and environmental risks were assessed for PAHs in water bodies from the Yitong River, and health risk assessment showed that exposure to PAHs in the water is not a health risk for human beings; however, the risk for children is higher than that for adults and requires attention. Although the environmental risk is moderate, the risk from Benzo(a)anthracene(BaA) alone is high and requires ongoing attention. In terms of the sustainability of drinking water sources, consideration should be given to taking necessary regulatory and protective measures to prevent further contamination. These results serve as a guide for managing PAHs in urban water bodies and managing water pollution.