Characteristics of soil heavy metal contents and its source analysis in affected areas of luning coal mine in huaibei coalfield

Abstract

This study analyzed the content characteristics, ecological risks, vertical migration characteristics and sources of soil heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) in affected areas of Luning Coal Mine. Results showed that the average contents of Cr, Pb, Cu, As and Cd exceeded the surface soil background values of Anhui Province, but the risk of soil ecological environment was low. Cd had the largest single factor pollution index, As followed, and Cd in 14 sampling points reached the warning limit, 95% of the samples were in moderate hazard, 5% of the samples were in strong hazard, but the potential ecological hazard index of many kind of heavy metals was 81.81~121.41, which was low ecological hazard. The difficulty of vertical migration of heavy metals in soil was from easy to difficult: Cr>Ni&Cu>As>Zn>Cd&Pb; Cu, Zn and Pb were related to automobile exhaust emissions and transportation dust, Cd and Ni were mainly caused by natural geological processes, leaching of coal gangue hill and the discharge of industrial pollutants, As was mainly caused by agricultural activities, and Cr was closely related to coal combustion.