Distribution and ecological risk assessment of 6 typical trace elements in mining soils in Huainan coalfield

Accumulation of coal gangue can release trace elements into the surroundings, causing severe soil pollution. To access the soil deterioration and environmental contamination by trace elements under the coal mining activities, soil and coal gangue samples were collected from 3 different mines (Xinzhuangzi, Panyi, Guqiao) in Huainan city, Anhui Province, China. Concentrations of trace elements (Cd, Cr, Cu, Ni, Pb and Zn) were determined using an inductively coupled plasma atomic emission spectrometry (ICP-AES). The results show that Cd is the only one element that exceeded the soil background of Huainan. There are no obvious characteristics for horizontal trace metal distributions. The oldest mine presented the worst contamination for the time effect (old mine> middle aged mine> new mine). The soil pollution assessment using individual pollution index suggests that Cd presents light pollution in Xinzhuangzi Mine, and minor pollution in Panyi and Guqiao Mine. The three mines all present moderate pollution risk evaluated using superimposed indices. Potential ecological risk index indicates that Cd element poses a considerable potential ecological risk, and the soil of the three mining areas has medium ecological risk.