A study of pollution of heavy metals in surface water sediments — A case study of the gold mining area in Xiaoqinling, Puyugou

In this paper, the surface water and sediments of gold mining area in Xiaoqinling, Puyugou were taken as the research objects to investigate the enrichment of heavy metals. Contents of various heavy metals in the surface water and sediments were tested systematically. The osculating method and index´s method of pollution of heavy metal were used together to evaluate and analyze the test results. The research results can provide technical reference for the environmental restoration and governance. The results show that there is a small mount of Cu and Zn tested in the surface water and sediments of upstream which is not affected by mining activities. It indicates that the surface water and sediments of upstream have not been polluted. While surface water and sediments of midstream and downstream are relatively polluted by C, Zb, Pb, Cd and Cr whose contents are 1.3, 4.27, 4.75 and 5.44 times above the allowed figures respectively, which doesn´t meet the water quality requirement of field irriqation. The PLI of the sediments of midstream and downstream have reached I and II grade and the sediments have been seriously polluted. Three conclusions can be drawn: (1) The downstream water is unfit for irrigation; influenced by the flow of surface water and leaching water of mining waste, heavy metals move and accumulate in the sediments, so the pollution of the sediments in downstream is relatively serious. And (3) the surface water and heavy metal sediments of the mining area have been polluted severely, and need urgent treatment.