Econ. Environ. Geol. 2003; 36(6): 469-480
Published online December 31, 2003
© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY
Correspondence to : Pyeong-koo Lee
Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co
dissolutions became importantly increased in tailings. The experimental solubility of Zn, Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within tailings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co?Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn>Cd>Cu>>Co>Pb?As for contaminated soils, and Pb>>Zn>Cd>As>Co >Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.
Keywords pH, leaching, heavy metal, tailings, contaminated soils
Econ. Environ. Geol. 2003; 36(6): 469-480
Published online December 31, 2003
Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.
Pyeong-koo Lee*, Min-ju Kang, Sung-won Park and Seung-jun Youm
Department of Geological and Environmental Hazards, Korea Institute of Geoscience and Minerals, Daejeon 305-350, Korea
Correspondence to:
Pyeong-koo Lee
Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co
dissolutions became importantly increased in tailings. The experimental solubility of Zn, Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within tailings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co?Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn>Cd>Cu>>Co>Pb?As for contaminated soils, and Pb>>Zn>Cd>As>Co >Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.
Keywords pH, leaching, heavy metal, tailings, contaminated soils
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