The analysis and evaluation on the features of the heavy metals in coal mining soil in the middle reaches of the Yellow River

Based on the investigation of the soil environments in the important coal mines in Shenmu City which locates in the middle reaches of the Yellow River, the contents and spatial distribution features of the heavy metals in the soil were studied by means of the enrichment factor method and the potential ecological hazard index method. The results are as follows: ①Only the variation coefficient of Ni element is above 50% in the area under study; the average values of Cd, Hg and Ni are higher than those of the soil background value of China and Shaanxi respectively; the heavy metals in the soil do not exceed the standard value; the distribution of Hg, Cd, Cu, Pb, Cr and Zn elements in the area under study is generally high in the north and low in the south, and the high values are mainly distributed in the north.②The enrichment degree of heavy metals in the area under study is Hg > Cd > Pb > Cr > Zn > As > Ni, and the potential ecological risk is Hg > Cd > As > Cu > Pb > Ni > Cr > Zn; the comprehensive potential ecological risk is moderate, except Hg and Cd, the ecological risk of the other six heavy metals is low. The research results can provide effective reference for carrying out production, ecological protection and restoration of mines under construction, and supporting ecological protection and high-quality development of the Yellow River Basin.