Evaluation of Heavy Metal Pollution in Soils from a Mining Area in Southern Jiangxi

This is a paper in the field of mining environmental engineering. Contents of heavy metals in 40 soil samples from a mining area in the Southern Jiangxi Province were determined. Results suggest that average contents of Cu, Pb, Zn, Cr, Ni, Cd and Hg were all lower than the background values of soil heavy metals in the Jiangxi Province, while the content of Pb was higher than the background value. The significant positive correlations between Cu, Cr, Ni, and Cd, and Zn and Cd, and Ni, Cr, Cd, As, and Hg indicated that these heavy metals may have homologous or concomitant sources. The single pollution index method, Nemerow index method, pollution load index method, and potential ecological risk index method were used to evaluate the pollution degree of soil by heavy metals in study area. Results of the single pollution index method showed that the single element pollution degree decreased following the sequence of Pb > Cd > Zn, while the overall pollution degree was low. The Nemerow index method revealed that soils being heavily polluted by heavy metals were mainly distributed in the mining area and middle reaches of river. The mean value of heavy metal pollution coefficient calculated from the pollution load index method decreased following the sequence of Pb > Cd > Zn > Cr > Cu > Hg > Ni. The soil pollution load index was moderate. The potential ecological risk assessment revealed mild ecological risk in relevant of Cu, Pb, Zn, Cr, and Ni, while much higher ecological risk was observed regarding Cd and Hg. In combination of the four pollution evaluation methods, soils from the study area were at the mild to moderate ecological risk in relevant of the eight heavy metals, indicating relatively good soil quality in the study area.