Characteristics and Sources of Selected Halocarbon and Hydrocarbon Volatile Organic Compounds in Surface Water of the Han River Basin

Abstract

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.