河南陕县赤泥库周边土壤重金属污染评价

Heavy metals pollution assessment in soil surrounding Red Mud Ponds in Shaanxian,Henan

【目的】对河南陕县赤泥库周边土壤重金属污染特性和现状进行调查和评价。【方法】在陕县红旗沟、大坪赤泥库周边设置11个采样点，采集0~20 cm土层土样，测定土壤中重金属Hg、Cd、As、Cu、Pb、Cr、Ni、Zn含量，并用污染指数法和潜在生态危害指数法对重金属污染现状进行评价。【结果】与河南省土壤背景值相比，河南陕县赤泥库周边土壤重金属Zn、Cu、Cr、Hg、Ni的含量均较高，但低于我国土壤环境质量3级标准；Pb、Cd、As 含量均明显低于河南土壤背景值和我国土壤环境质量3级标准。单因子污染指数法和内梅罗综合污染指数法评价结果显示，研究区土壤污染最小的为Pb，污染最严重的为Cr，污染程度由高到低依次为Cr】As】Ni】Zn】Hg】Cu】Cd】Pb；赤泥库周边11个采样点土壤中各重金属元素污染程度属于安全范畴，污染水平为清洁。潜在生态危害指数法评价结果显示，Hg属于很强生态危害水平，其他重金属属于轻微生态危害水平；该地区总的潜在生态危害指数(RI)值为238.22，达到中等生态危害，其中3号采样点污染最为严重，RI值达到536.65，为强生态危害。【结论】河南陕县赤泥库周边土壤保护良好，重金属污染状况属于轻度污染，与河南省土壤背景值相比，土壤中重金属Zn、Cu、Cr、Hg、Ni的含量有累积，虽远远低于我国土壤环境质量3级标准，但其RI值达到中等生态危害水平，个别采样点甚至更为突出，因此建议相关部门进一步加强监测防治工作。

【Objective】This study focused on the investigation and evaluation for heavy metals pollution in soils surrounding Red Mud Ponds(RMP)in Shaanxian,Henan.【Method】Eleven sampling sites were selected in surrounding area of RMP in Hongqigou and Daping of Shaanxian and the contents of heavy metals(Cd,As,Zn,Pb,Cu,Hg,Cr,and Ni)in soil depth of 0-20 cm were measured and evaluated using single factor index,Nemerow integrated index and potential ecological risk index.【Result】Compared to the background values in Henan,the contents of Zn,Cu,Cr,Hg,and Ni in soil surrounding RMP were higherbut still lower than their third standards of national soil environmental quality.Contents of Pb,Cd,and As were significantly lower.Single factor index and Nemerow integrated index indicated that the pollution levels of heavy metals were in the order of Cr>As>Ni>Zn>Hg>Cu>Cd>Pb.The pollution levels of all the monitoring sites were safe.Based on potential ecological risk index method,the RI value of this area was 238.22,indicating medium ecological damage.In particular,RI value of No.3 monitoring site was536.65 with serious ecological damage.【Conclusion】The soil in surrounding area of RMP was well protected and the heavy metal pollution level was slight.Compared to the background values in Henan,the contents of Zn,Cu,Cr,Hg,and Ni were lower than their third levels of national standards.But RIvalue indicated medium ecological damage especially in some sites.It is suggested to enhance the monitoring and take protection measures.