Assessment of heavy metals and arsenic pollution in surface sediments from rivers around a uranium mining area in East China.

Taking the surface sediments of rivers near a uranium mine in East China as the research object, the concentrations of seven metals, including Cr, Cu, Ni, Pb, Zn, Cd and As, were analyzed. The pollution degree and ecological risk of heavy metals and arsenic were evaluated according to the geo-accumulation index, pollution loading index, potential ecological risk index and sediment quality guidelines. Finally, the sources of pollution were determined by Pearson's correlation analysis, principal component analysis and hierarchical cluster analysis. The results indicated that Cr, Cu, Ni, Pb, Zn, Cd and As in sediments showed varying degrees of contamination, using the soil background value of the study area as a reference, and Cd was the main excessive pollutant in the sediments. In most parts of the river, Cd has reached a moderate level of pollution. The potential ecological hazards at sampling sites 9, 13, 17 and 18 are significantly higher than the other sites because of the impact of urbanization and uranium mining and smelting. Cu, Zn, Cr, Ni and Cd are mainly derived from urban activities and the uranium industry, Pb is mainly derived from vehicle emissions, and As is mainly derived from nature and rocks.