Risk Assessment for Co-contaminated Soil Including As and Hg in the Vicinity of Abandoned Metal Mine

Abstract

Objectives:In Korea, about 2,000 abandoned mine area has been polluted by harmful waste such as mine tailing, waste rock and acid mine drain without prevention facility. Mine waste contains high concentrations of various hazardous metallic and nonmetallic materials. Also, it can be a source of pollution for nearby soil, rivers, and ground water. Heavy metals may exist in ecosystems for a long time and may be taken by the residents through crops and drinking water. In this study, human risk assessment for heavy metal contamination was carried out.Methods:About the 564 soil samples were analyzed for heavy metal. The risk assessment of polluted soils was carried out in accordance with guideline of Korea Soil Environment Conservation Act. It was implied with hazard identification, exposure assessment, toxicity assessment, and risk characterization.Results and Discussion:The number of exceed sites for the worried level of soil concentration were 185 for As, 3 for Hg, 7 for Zn, 1 for Pb, 1 for Cu. Soil contact was the biggest impact on adults and children for carcinogenic risk followed by crop intake, soil intake, and soil inhalation. Non-carcinogenic risk for adults, were in order of crop intake > soil intake > soil contact > outdoor air inhalation (volatilization) > ground water intake and soil inhalation. For children, it was in the order of soil intake > crop intake > soil contact > outdoor air inhalation (volatilization) > ground water intake > soil inhalation.Conclusion:The carcinogenic purification target concentration for the site was determined to be 7.17 mg / kg level of arsenic, considering adult and child concentrations. However, carcinogenic purification target concentration by arsenic dermal absorption carcinogenic coefficients (SF<sub>abs</sub>) of USEPA method was 20.08 mg/kg, therefore requiring research for domestic risk assessment factor.