| The Shizishan mining area is located7km east of Tongling. It is the biggest copper ore field amongst the metallogenic belt in the middle and lower reaches of Yangtze River. In addition, it is also one of the major Cu production bases in China. Over the years, mine exploitation caused a lot of environmental pollutions., Unfortunately, this problem is still growing. This paper revealed environmental problems of the Shizishan mining area and its surrounding areas, using heavy metal contents in different enviromental medium (soil, water and plants) as objects to investigate the geochemical characteristics of heavy metals in the Shizishan mining area. AFS, ICP-OES and ICP-OES were used to analyse the contents of As, Hg, Al, Fe, Mn, Cd, Zn, Cu, Pb, Ni, Cr etc.in soil, water and plants. These results showed different levels of heavy metal accumulation from different environmental medium in the Shizishan mining area and its surrounding areas.Tailings, ettle that produced by mining, and orebody oxidation zone contained a large number of heavy metal elements, especially Hg, Cu, As, Cd followed by Zn, Pb (etc.), which exceeded more than dozens or even hundreds of times of the second level of national soil standard. Cd, As, Cu, Hg were largely detected in polluted mining area and its surrounding areas, as well as the silt in the Shunan River. The contents of these elements have exceeded more than dozens or hundreds of times of the second level of national soil standard. Heavy metal elements in the surficial soil are mainly enriched in the mining area, the north of the mining area and the downstream of the river.Water waste produced from mining contains a lot of heavy metal elements, such as Hg, Cu, Cd, Zn. The containment of these elements in water waste exceeded more than tens or dozens of times of the first level of national water standard. The major heavy metal element that polluted surface water is Hg, which exceeded69times of the first level of national water standard. The major heavy metal elements that polluted the water of the Shunan River, are Hg and Cu, followed by Cr, Zn, Pb and etc. The major heavy metal elements that polluted the undergroundwater, are Mn and Hg, followed by Cr, Cu, As, Zn etc. The highest content of Mn in the undergroundwater exceeded13.6times of the limits of drinking water quality in conventional test. The highest content of Hg in the undergroundwater exceeded44times of the first level of national water standard and2times of the limits of the drinking water quality in conventional test. Heavy metal elements in the surficial water are largely enriched in the mining area and the south of the mining area.The contents of heavy metal elements of the grass and bamboo around the Yangshanchong tailing pool, such as Cr, Cu, Pb, Zn, As, Hg, Ni etc., are higher then the contrast samples. The contents of Cr, Cu, Pb, Zn,As, Hg, Cd etc. in vegetables from the farmland around the tailing pool exceeded the national standard, especially As and Pb which exceeded more than dozens or hundreds of times of national standard. The further the distance to the tailing pool, the lower the heavy metal contents. The enrichment of heavy metal contents in the grass from the Shunan Rive and its surrounding ditches, such as Cr, Cu, Pb, Zn, As, Hg, Ni etc., are higher than the contrast/control samples. The contents of Pb,Zn,As,Hg and Cd in the green vegetables, rape and rice from the farmland next to the Shunan River, are higher than the contrast/control samples, except Zn in rice. The contents of As and Pb are particularly high followed by Hg, Cd, Zn, which exceeded more than dozens or hundreds of times of national standard.In conclusion, this study revealed that tailings, ettle, orebody oxidation zone, and water waste from mining were discarded during the long term mine production, and it is the major cause of the heavy metal enrichment in soil, silt, surface water, undergroundwater,and plants in the Shunan River, the Shizishan mining area and its surrounding areas. |
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