煤矿复垦区土壤重金属分布特征与质量评价

Distribution characteristics of heavy metals in reclamation area of coal mine and its quality evaluation

为保证煤矿复垦区种植农作物的充填复垦土壤的生态安全,以淮南矿区煤矸石充填复垦地为研究对象,通过对研究区内Cd、Cr、Ni、Pb、Cu、Zn和Hg 7种重金属不同深度含量分析,总结其纵向分布特征,并将研究区土壤重金属含量与淮南市土壤背景值、《土壤环境质量标准》(GB 15618—1995)作比较,分析这7种重金属的污染程度。结果表明,这7种重金属都有不同程度的污染,其中土壤受Cd污染最严重,土壤中重金属垂直方向上无确定分布规律。总体而言,土壤重金属潜在生态风险属于强生态危害。从垂直方向来看,重金属潜在生态风险指数(RI)随着深度的增加出现先下降后升高的趋势,其中40～60cm深度的RI最大。重金属生态危害程度依次为Cd>Hg>Ni>Cu>Cr>Pb>Zn,其中Cd为矿区土壤中最主要的重金属污染生态风险因子。

A gangue filled reclamation land in Huainan mining area was selected as target area to study the ecological safety of applying reclaimed lands for agriculture use.The contents of heavy metals（Cd,Cr,Ni,Pb,Cu,Zn and Hg） at different depths of soil were determined and their vertical distribution was analyzed.The pollution level of heavy metals was evaluated by comparison their content with local background values and environment quality standards.Results showed that the reclaimed soil was contaminated by the 7 heavy metal to varied degree and Cd pollution was the most evident.The vertical distribution of heavy metals had no regular rules.The potential risk index showed the soil was contaminated strongly.From the vertical perspective,the potential risk index（RI） was decrease first and then increase with depth down and the RI of the 40-60 cm depth soil was the largest.The pollution degree of 7 heavy metals followed the order of CdHgNiCuCrPbZn.Cd was the primary ecology risk factor in reclaimed soil.