Investigation and Evaluation of Heavy Metals in Haizhou Open-pit Mine and Surrounding Water Environment

The water quality of shallow underground water, mine drainage water and surface water in Haizhou open-pit mine and surrounding areas were tested, and the investigation and evaluation of heavy metal pollution in water environment were carried out. The investigation results showed that in the shallow groundwater, Cu was Ⅲ class or better than Ⅲ indexes. The percentage of Pb meeting Ⅳ or Ⅴ class index was 86.21%. The portion of Ni reaching Ⅳ or Ⅴ class index was 58.62%. The percent of Cr⁺⁶ meeting Ⅳ or Ⅴ class index was 17.24%, and that of Mn reaching Ⅳ or Ⅴ class index was 20.69%. Pb and Ni were the main pollution indicators in the survey area, and the seriously polluted areas are mainly distributed in the vicinity of gangue mountains and dump sites. In the mine water, Cu achieved Ⅲ classes or better than Ⅲ indexes; Cr⁺⁶ achieved Ⅲ classes or better than Ⅲ indexes; Only 25% of Ni could meet Ⅳ or Ⅴ class indexes. Seventy-five percent of Pb and Mn could reach Ⅳ or Ⅴ class indexes. In surface water samples, the Pb content of one group of samples exceeded the standard and was unqualified. According to the results, the rest of the samples were in the standard range. Shallow groundwater in some residential areas, deep mine drainage in Haizhou mine and surface water of river main stream can be used for various purposes. Other underground or surface water may be used for industrial, environmental or agricultural purposes. The research results built the basis for the comprehensive management of Haizhou open-pit mine and its surrounding environment, and also provided a useful reference for the investigation of similar open-pit mines in Northeast China.