Soil contamination with TCE in an industrial complex: contamination levels and implication for groundwater contamination

We examined levels of soil contamination by trichloroethylene (TCE) at an industrial complex in Wonju, Korea. The examination was focused on the surrounding area of an asphalt laboratory where TCE had been used as a solvent for testing the asphalt quality. TCE contamination in soil was found at depths of 1∼5 m and ranged between 0.13 and 14,702.82 mg/kg. However, the soil contamination was restricted in immediate proximity of the laboratory. Batch isotherm experiments showed that there was a linear relationship between the sorbed concentration and the aqueous TCE concentration, which is typical for non-polar organic chemicals such as TCE. The distribution coefficient (Kd) ranged between 0.375 and 0.639 L/kg and increased with depth. Considering TCE concentration in deep soil, Kd and higher groundwater level, TCE concentration in groundwater can reach up to 19.36 mg/L. In addition, highly weathered and fractured rocks, where groundwater level formed, underlain by the contaminated soil zone can facilitate vertical TCE movement and form an extensive groundwater plume in the downgradient area. As a source removal measure, the contaminated soil at the presumably hot source zone had been remediated in 2004.