Objective The purpose of this work is to analyze the pollution risks and sources of heavy metals in surface soil in Huangshi city, a resource-exhuasted city, and to support the protection of ecological environment and human health.

Method 49 soil samples were collected and examined heavy metal content, which were Cr, Ni, Pb, Zn and Cu. Pollution levels were evaluated in line with Geo-accumulation index and potential ecological risk index, and the distribution patterns of heavy metals were depicted by spatial interpolation method. Furthermore, PCA (principal component analysis) and PMF (positive matrix factorization) were applied to analyze the sources of heavy metals and their contribution to each element.

Result All the five heavy metals had their mean values higher than the soil background values in Hubei province, among which Zn and Pb were the most enriched elements. The potential ecological risk for each element and the comprehensive ecological risk for the overall area were similarly in the lower risk levels. Among five elements, Pb was classified the most polluted element whereas Ni the slightest polluted element. In addition, the spatial distribution of heavy metals was roughly characterized by lower values in the middle area and higher in the surroundings, specifically Cr and Ni were low and evenly distributed, while Pb, Zn and Cu had their higher values mainly distributed in areas with dense human activities.

Conclusion The results showed that there were three main sources of soil heavy metal pollution, with Cr and Ni were mainly from natural sources, Pb and Zn mainly from transportation sources, and Cu mainly from mining sources.