Environmental contamination and bioaccessibility of arsenic and metals around the Dongjeong Au-Ag-Cu mine, Korea

The objectives of this study were to investigate the level of arsenic and metal contamination of soils, crop plants and waters around the Dongjeong Au-Ag-Cu mine, and to assess bioaccessibility of metals in soil and plant using the EHS (extraction of heavy metals in stomach and small intestine) test. The EHS test was used to simulate the conditions in the human stomach and small intestine. In tailings, the mean concentrations of elements from the mine area were As 4070 mg kg (super -1) , Cd 6 mg kg (super -1) , Cu 380 mg kg (super -1) , Mn 7760 mg kg (super -1) , Pb 19 150 mg kg (super -1) , Zn 2590 mg kg (super -1) and Hg 2.8 mg kg (super -1) . Mountain soils adjacent to the tailings and waste rock piles were significantly contaminated by these elements. Farmland soils contained higher concentrations of As, Cd, Hg, Mn, Pb and Zn than soils at the control area, especially As and Pb which were over permissible levels. Metals were accumulated in crop plants grown on farmland soil near the mine area. The concentrations of metals were higher in leafy plants than in grain plants such as rice grain and red pepper. The concentrations of SO (sub 4) (super 2-) , Mn and Zn were elevated in stream water and were influenced by effluents from the tailings and waste rock piles. The concentrations of Cd and Pb in groundwater were higher than the permissible levels for drinking water in Korea. The results of the EHS test showed c. 60% of Cd, 10% of As and 30-40% of Cu, Pb, Mn and Zn were present as a bioaccessible fraction in farmland soils. In crop plants, high percentages of total concentrations of metals except Pb were extracted as bioaccessible concentrations. Bioaccessible concentrations of metals may be valuable for providing the input data for risk assessment at sites subject to anthropogenic soil contamination.