A Comparative Study on the Pollution and Speciation Characteristics of Heavy Metals between the Gold and Iron Mine Tailings of the Upstream Area of Miyun Reservoir, Beijing

摘要

In order to have a comparative investigation of the pollution and speciation characteristics of heavy metals between the gold and iron mine tailings of the upstream areas of Miyun Reservoir, the tailing samples from the typical gold and iron mines were analyzed. The total metal concentration is determined by acid digestion and the chemical fractionation of metal by the Tessier sequential extraction method. It is found that compared to background values of Beijing, the heavy metal in both gold and iron mine tailings is higher, while the heavy metal in gold mine tailings is higher than that of iron mine tailings, with Mn as an exception. Mercury is the most serious pollution element in gold mine tailings. Results of the sequential extraction suggest that the exchangeable of Cd exhibits the highest percentage of total metal in gold and iron mine tailings (15% and 6.5% of the total metal, respectively) among Cd, Mn, Zn, Cu, Pb, Cr. In the majority of iron mine tailing samples collected, large amounts of Cu were mainly associated with the organic form. The percentage of the bioavailable metals in both gold and iron mine tailing samples follows the order: Cd>Mn>Zn>Cu>Pb>Cr.