湖南采矿区和冶炼区水稻土重金属污染及其潜在风险评价

Heavy metals pollution and potential ecological risk in paddy soils around mine areas and smelting areas in Hunan Province

对湖南省9个县市采矿区和冶炼区附近的水稻土中重金属Cd、As、Cu、Zn和Pb进行了调查和分析.结果表明,采矿区和冶炼区周围的水稻土中重金属Cd、As、Cu、Zn和Pb的含量呈对数正态分布.单因子污染指数法评价表明,在所调查的区域中,有6个县市矿区和冶炼区附近的水稻土受到Cd的严重污染,其它地区的水稻土分别受到Cd、As、Cu、Zn和Pb不同程度的污染,其中衡阳常宁市水口山铅锌矿区和株洲清水塘冶炼区附近的水稻土受到重金属的严重污染.潜在风险评价表明,采矿区和冶炼区周围的水稻土中Cd潜在风险参数最高,其次是Pb和As.衡阳常宁水口山铅锌矿、株洲清水塘冶炼区、娄底冷水江锡矿和湘潭锰矿附近的水稻土中重金属的潜在生态风险参数很高,具有很高潜在风险程度;永州道县冶炼区水稻土中重金属的潜在生态风险程度为较高程度;郴州柿竹园铅锌矿、常德石门雄磺矿、益阳赫山区金矿区和岳阳临湘铅锌矿区附近的水稻土的重金属潜在生态风险为中等程度.

The pollution status and total contents of heavy metals, namely, Cd, As, Cu, Zn, and Pb, in paddy soils around mine areas and smelting areas of 9 cities in Hunan province were analyzed. The results indicated that the natural logarithmic concentrations of the analyzed heavy metals followed normal distributions. According to pollution index, the paddy soil samples collected from 6 cities were severely contaminated with Cd; moreover, other heavy metals, such as As, Cu, Zn, and Pb were found in paddy soils at various elevated concentrations. The paddy soils collected from the Hengyang Shui kou-shan lead/zinc mine and Zhuzhou Qing shui-tan smelting areas had the most serious heavy metal contamination. The potential ecological risk factors （El） for Cd in the investigated cities were the highest, followed by Pb and As. Ei values and heavy metal presence at the following sites were particularly high： Hengyang Shui koushan lead/zinc mine, Zhuzhou Qing shui-tan smelting, Loudi Leng shui-jiang tin mine, and Xiangtan manganese mine areas. Furthermore, the considerable potential ecological risks for heavy metals were found in the Yongzhou Daoxian smelting area. The results also indicated that the paddy soils from Chenzhou Shi zhuyuan lead/zinc mine, Changde Shimen realgar mine, Yiyang gold mine, and Yueyang Linxiang lead/ zinc mine areas exhibited moderate potential ecological risk.