Heavy Metal Pollution And Risk Assessment In The Soil Of The Metal Mining Area In The Upper Reaches Of Miyun Reservoir In Beijing

The contents and extractable contents of heavy metals (Mn, Zn, Cu, Pb, Ni, V, Cr, Cd, As, Hg) in soils of iron and gold mine areas of Miyun Reservoir upstream in Beijing were analyzed in this article. Heavy metal contamination in soils of iron and gold mine areas was evaluated by Chemometric methods and risk assessments.The results showed that the contamination of most heavy metals in mine areas were exceeded the soil background of Beijing. Average exceeded a multiple of Ni, Cr, Hg in soils of iron mine areas larger, were2.38times,3.68times and6.67times, respectively. In gold mine areas, the highest value of average exceeded a multiple was Hg (7.67times), and the minimum value of that was As (0.95times). Heavy metal contamination in soils of iron mine areas was higher than the gold mine areas. Heavy metal contamination in soils of iron mine areas was Hg>Cr>Ni>Zn>Cu>Cd>Mn>Pb. Heavy metal contamination in soils of gold mine areas was Hg>Cr>Cd>Cu>Ni>Zn>Mn>Pb>V. Soil toxicity of heavy metal in soils of mine areas was evaluated by Sediment Quality Standards (SQG). In iron and gold mine areas. Ni in soils was a serious pollution, Cr in soils was a moderate pollution, As, Pb were a moderate pollution in addition to some sampling points.The fractions of heavy metals (Mn, Zn, Cu, Pb, Ni, V, Cr, Cd) in soils were analyzed by BCR sequential extraction procedure. The fraction of heavy metal was divided into exchangeable, reducible, oxidizable and residual. In iron and gold mine areas, the highest value of exchangeable fraction contents of Mn was0.20mg/kg-347.55mg/kg and42.33mg/kg-844.69mg/kg. Exchangeable and reducible fraction contents for Mn. Pb and Zn in iron mine areas respectively accounted for about50%?30%?20%of the total concentration, and that in iron mine areas respectively accounted for about60%?40%?30%of the total concentration. Exchangeable and reducible of heavy metal in soils were potential pollution. Residual fraction of Cr, Ni, V in soils in mine areas was not easy to pollute environment.Heavy metal contamination in soils of iron and gold mine areas was evaluated by Correlation and Cluster Analysis. The correlation of some heavy metal of different mining areas was very high, having the same sources of pollution and geochemical properties. The principal component analysis showed that the first component of iron and gold mine areas able to explain nearly46.13%,41.28%of the amount of information, reflecting Cd. Cu. Pb. Zn. Mn. As and Cu?Mn?V?As concentration. The major source of pollution in mine areas was in discharge of mining wastewater and tailing leaching, may be residents living pollution and atmospheric deposition. The load values of sampling points, heavy metals, morphological matrix distribution in mine areas were discussed by Tucker3model. The Tucker3model further demonstrated that potential hazards of heavy metals in mine areas.Heavy metal contamination in soils of iron and gold mine areas was discussed by Geo-accumulation Index, Potential Ecological Risk Index, Fuzzy Comprehensive Evaluation. Cr and Hg in soils of iron mine areas were higher pollution, Cd and Hg in soils of gold mine areas were higher potential hazards. The pollution of heavy metals in gold mine areas was higher than in iron mine areas. The pollution of heavy metals in iron mine areas was alert level (Grade3), and that in gold mine areas was security level (Grade2), because the Fuzzy Comprehensive Evaluation eliminated the ambiguity of boundary between the mine areas.Heavy metal contamination in soils of iron and gold mine areas was analyzed in this article. The conclusion will provide scientific basis in mine environmental pollution control and protection of Miyun Reservoir in Beijing.