달성Cu-W 광산 주변 수계의 하상퇴적물과 자연수의Cd, Cu, PB 및Zn 오염

In order to investigate the extent and degree of Cd, Cu, Pb and Zn contamination affected by mining activities of the Dalsung Cu-W mine, sampling of stream sediments and waters has been undertaken up to 1.5km downstream from the mine at 50-150meter intervals. Analysis of the samples was carried out using ICP-AES for Cd, Cu, Pb and Zn. Physical and chemical properties of sediments (pH, organic matter contents, cation exchange capacity) and waters (pH, Eh and temparature) were also measured. The properties of the sediment samples were characterizes by low pH(3.0-5.5), low organic matter contents(2-5%) and a morderate degree of cation exchange capacity(7-15meq/100g) with a high proportion of sand fraction. The pH values of water samples ranged from 3.0 to 5.0 and the Eh levels were in the range of 350-530mV. Concentrations of Cd, Cu, Pb and Zn in the sediments averaged 3.2mg/kg, 1,390 mg/kg, 451 mg/kg and 263 mg/kg with the range of 0.6-11.4 mg/kg, 15-3,800 mg/kg, 14-1,330 mg/kg and 63-1,060 mg/kg, respectively. Significant levels of the heavy metals were also found in the water samples with the range of 10-170μgCd/l, 300-41,600μgCu/l, 10-80μgPb/l and 700-15,400μgZn/l. These elevated concentrations in the sediments and waters may be caused by the weathering of mine waste materials and their high solubilities under acidic and/or oxidizing conditions. Although metal concentrations in the samples decrease with the distance from the mine, heavy metal contamination of sediments and waters were also found at the 1.5km downstream due to the mobile conditions of the heavy metals, with particular reference to Cd and Zn in stream waters.