Fractionation and Potential Mobility of Heavy Metals in Tailings and Paddy Soils near Abandoned Metalliferous Mines

Most of the tailings have been left without any management in their mines and have become the main source of serious environmental problems in nearby groundwater, stream and cultivated lands. To compare fractionation and potential mobility of heavy metals in tailings and paddy soils near abandoned 10-metalliferous mines in Korea, the distribution and chemical fractions of heavy metal and their mobility in relation to chemical compositions were investigated. The pollution index of heavy metal in mine tailing calculated with the permissible levels were in the order Cheongyang>Dogok>Beutdeun>Baegwoul mine, which were considered sufficient to raise environmental problems. The rates of 0.1M-HCl extractable Cd, Cu, Pb, Zn, and Ni to total content in paddy soils were 49.1, 50.7, 26.8, 18.4 and 2.9%, respectively, and their rates of heavy metals in paddy soils were higher than that of mine tailing. Dominant chemical forms of heavy metals in tailings were sulfide and residual form (63-91%), specially, the exchangeable portion of Cd (21%) was relatively higher than that of other metals in paddy soils. The mobility factor of heavy metals in tailings and paddy soils was in the order Cd>Zn>Cu>Pb, and the mobility factor in tailing varied considerably among the mines. The potential mobility of heavy metals in tailings showed significant positive correlation with water-soluble and contents, while in paddy soils, it correlated negatively with soil pH values.