小店污灌区表层土壤重金属分布特征及生态风险评价

Distribution and ecological risk assessment of heavy metal pollution in surface soil of Xiaodian sewage irrigation area

以太原市小店污灌区农田土壤（0-20cm）为研究对象,分析了Hg、Cd、As、Pb、Cr、Zn及Cu的含量,评价了污灌区农田土壤的污染程度及潜在生态风险.结果表明,污灌区农田土壤均受到了不同程度的重金属污染,7种重金属元素含量均未超过土壤环境质量二级标准,但平均含量均显著高于研究区背景值,土壤总体表现为以Hg为主的多种重金属富集;相关性表明,Cu与Cd、As、Zn,Zn与Cd、Pb、Cr、Cu,Cr与As、Pb、Zn,Pb与Cd、Cr、Zn呈显著相关;各种重金属内梅罗综合指数和地质累积指数由大至小依次为Hg、Cd、As、Cu、Cr、Zn、Pb;综合污染评价和综合潜在生态风险评价表明,该区域总体呈现中度污染和中等潜在生态风险水平.污灌区农田土壤中Hg、Cd、As、Pb、Cr、Zn、Cu 7种重金属元素明显积累的现实应该引起有关部门的足够重视.

The concentration of Hg,Cd,As,Pb,Cr,Zn and Cu in the top soil（0-20cm）of Xiaodian sewage irrigation area located in Taiyuan were analyzed by field sampling and laboratory analysis,aiming to evaluate the severity of heavy metal pollution and potential ecological risk of the contaminated soil.The results show that the soil environment in Xiaodian sewage irrigation area is qualified for the second level criterion of standard of soil environment.Then the average contents of Hg,Cd,As,Pb,Cr,Zn and Cu were greater than their background values.And it was observed that multiple heavy metal enrichment mainly due to Hg.The Nemerow index and geoaccumulation index of heavy metals was Hg〉Cd〉As〉Cu〉Cr〉Zn〉Pb.Integrated pollution index showed that the investigated area was moderately polluted by the heavy metals;and the integrated potential ecological risk index showed that the potential ecological risk level for the area was moderate.Heavy metal pollution was obviously accumulated in sewage irrigation area as human activities;and attention should be paid to it.