| With Yintai District of Tongchuan City Yuhua town background value of heavy metal as the standard, the paper comparatively analyzes Pb, Cd, Cu, Zn, Cr, Fe and the accumulation of six heavy metals in the soils of Yuhua Coal Mine, meanwhile, the methods of single-factor pollution index, integrated pollution index and the potential ecological risk index are applied for the evaluation of heavy metal pollution. The results show that in the study area, the existence of certain heavy metals Pb, Zn enriches cumulative trend, the average content levels higher than the corresponding background values to 31%, 27.08%. Cd, Cu, Cr, Fe accumulation is not clear.By Nemerow pollution index method, the paper gets the comprehensive study of soil heavy metal pollution. Pb, Cd, Zn were heavy pollution, and the soil, crops have been polluted heavily. Fe, as the light pollution, has passed the background value. Cu is in safety state while Cr is in the warning limits.The study on assessment of potential ecological risk in heavy metal contamination of soil concludes that Cu and Cr obtained mild ecological risk; Zn moderate; Pb and Cd was very strong. It is shown that Pb and Cd have a higher degree of potential ecological harm.Vertical profiles of soil results show that Pb and Zn are mainly enriched in the surface layer between 0 ~ 20cm; Cr and Fe is not an obvious stratification; Cu increased with soil depth has been enriched; all heavy metals Elements in the following decrease in 60cm, 80cm less stable state.The research of study area in the north of the mine pit water results shows that heavy metals except iron in the soil around mine water have nothing to do with the mine water.The results show that the mining process has already had the environmental hazards to the coal mining, coal mining activities and long-term accumulation of heavy metals in soil and mine make a significant contribution to the pollution. So long cumulative soil contamination should attract the concerns. |
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