Heavy Metal Distribution And Ecological Risk Assessment In Xikuangshan Hunan Province

A lot of heavy metal transport emissions of mining on the surrounding cause serious environmental pollution and health threats.This study was focused on the heavy metal pollution in the soils around the smelting factories in the Xikuangshan area in Lengshuijiang city, Hunan province. Through field surveys, snake-like sampling, Determination of heavy metal,classical statistics, geostatistics and ecological risk assessment to define heavy metal pollution in the area and spatial distribution of sources. In the area of 98 square kilometers,83 soil samples and 23 plant samples were collected and eight elements in these samples, including Cd, Cr, Cu, Pb and Zn were determined by ICP-MS,and Sb,As and Hg were determined by AFS-820.The results of correlation analysis, principal component analysis and cluster analysis showed that As, Zn, Cu and Pb around the smelter may probably come from the same pollution sources, whereas Cr might come from the parent soil.Additional Sb, Hg and Cd pollution sources may exist except the smelter.The analysis results of showed that the pollution degree of Sb,As,Pb,Zn,Hg and Cd increased when coming near the smelting factories;the raising dust from tailing dams might result in addional Cd,Sb and Hg pollution.The choice of different plants absorb different heavy metals, Heavy metal content of plants in different parts of the order of addition to Sb, Cd showed the ground Section higher than underground parts, Cr, Pb, Hg, As were shown to underground higher than the ground Section. Beside the uptake from soil, the translocation from leaf is also an improtent transmitting channel for heavy metals accumulation in plants in the study area.The order of impacting extent of ecological risk is Cd>Sb>Hg>As>Pd>Zn >Cr,and the degree of total potential ecological assessment is serious.Cd is the highest of the degree of single element pollution, and the pollutions form Pb and As has become potential threat. The soil around the Xikuangshan smelting factories has been polluted severely by Cd,Sb and Hg. Ecological risks of all the samples except one site far away from the mine entrance are moderate to severe, and the risk of Cd,Sb and Hg are the most severe among all the heavy metals. Farming is suggested to be no longer suitbale in the 10 squarekilometers around the smelting factories.