Increasing public awareness about the aesthetics and safety of water sources has shifted researchers’ attention to the adverse effects of volatile organic compounds (VOCs) on humans and aquatic organisms. A total of 17 VOCs, including 10 volatile halogenated hydrocarbons and seven volatile non-halogenated hydrocarbons, were investigated at 36 sites of the Han River Basin, which is the largest and most important drinking water source for residents of the Seoul metropolitan area and Gyeonggi province in South Korea. The VOC concentrations ranged from below detection limits to 1.813 µg L⁻¹. The most frequently detected VOC was 1,2-dichloropropane, with a detection frequency of 80.56%, as it is used as a soil fumigant, chemical intermediate, and industrial solvent. In terms of geographical trends, the sampling sites that were under the influence of sewage and industrial wastewater treatment plants were more polluted with VOCs than other areas. This observation was also supported by the results of the principal component analysis. In the present study, the detected concentrations of VOCs were much lower than that of the predicted no-effect concentrations, suggesting low ecological risk in the Han River. However, a lack of available ecotoxicity data and limited comparable studies warrants further studies on these compounds.

Volatile organic compounds (VOCs) are ubiquitous pollutants in surface water, which is the main source of drinking water in South Korea. We investigated the behavior (concentration, distribution, and environmental risk) of eleven selected VOCs in the surface water of the Han River tributaries using purge-and-trap gas chromatography/mass spectrometry. The average concentration of VOCs was 0.29 ± 0.47 μg/L. Chloroform and trichloroethylene (TCE) were the major pollutants, accounting for approximately 64.2% and 25.6% of the total concentration, respectively, and showing that halocarbons accounted for 94%. Chloroform was positively correlated with TCE and xylenes, and TCE was positively correlated with tetrachloroethylene (PCE). No differences were observed in the temporal average concentrations of total VOCs, but the concentrations differed significantly among sub-watershed areas. The Imjin-Hantan River, Han River mainstream, and Anseong Stream watersheds had a high positive association with TCE, whereas the Bukhan and Namhan River watersheds had a strong positive link with chloroform. The contamination and detection frequency of VOCs were highest in industrial complexes, followed by urban and rural areas. Thus, point source pollution significantly contributed to VOC contamination of these tributaries. Risk quotients for most VOCs were <1, suggesting negligible risk. Considering the relatively high occurrence of VOCs and their potential ecological risks, continuous environmental monitoring and study of environmental impacts based on ecotoxicity studies of domestic aquatic species are warranted.