Effects of land use on the spatial distribution of trace metals and volatile organic compounds in urban groundwater, Seoul, Korea

To investigate the urban groundwater contamination by eight trace metals and 69 volatile organic compounds (VOCs) in relation to land use in Seoul, a total of 57 groundwater samples collected from wells were examined using a non-parametric statistical analysis. Land use was classified into five categories: less-developed, residential, agricultural, traffic, and industrial. A comparison of analyzed data with US EPA and Korean standards for drinking water showed that some metals and VOCs exceeded the standards in a few localities, such as Fe (N=5), Mn (N=6), Cu (N=1), TCE (N=6), PCE (N=8), 1,2-DCA (N=1), and 1,2-dichloropropane (N=1). Among the 69 investigated VOCs, 19 compounds such as some gasoline-related compounds (e.g., toluene) and chlorinated compounds (e.g., chloroform, PCE, TCE) were detected in groundwater. Non-parametric statistical analysis showed that the concentrations of most trace metals (Fe, Mn, As, Cr, Pb, Cd) and some VOCs (especially, TCE, PCE, chloroform; toluene, carbon tetrachloride, bromodichloromethane, CFC113) are significantly higher in the industrial, residential, and traffic areas (P<0.05), indicating that anthropogenic contamination of urban groundwater by those chemicals is growing. Those chemicals can be used as effective indicators of anthropogenic contamination of groundwater in urban areas and therefore a special attention is warranted for a safe water supply in those areas. The results of this study suggest that urban groundwater quality in urban areas is closely related with land use.