新疆伊宁县牧区土壤重金属潜在生态风险评价

Assessment of Potential Ecological Risks of Heavy Metals in the Soils of Yining Pasture, Xin Jiang

应用Hakanson潜在生态风险指数法对新疆伊宁县铁列克萨伊山牧区土壤As、Pb、Cd、Cu、Zn和Ni含量特征进行研究,确定了研究区域土壤重金属的含量水平、对牧区潜在生态风险程度进行了评价,并分析了主要污染因子。结果表明:该牧区土壤重金属As、Pb、Cd、Cu、Zn、Ni的平均值分别为11.56、4.85、0.15、64.80、123.84、11.56 mg/kg,Cu、Zn的均值超出国家土壤环境质量一级标准,其余重金属均值未超标。在检测的34个样点中,Cu、Zn的超标率为97%,Cd、As有部分样点超标。但从潜在生态风险指数来看,该研究区域处于低潜在生态风险。各重金属潜在生态风险由高至低顺序为Cd>Cu>As>Ni>Zn>Pb,其中Cd为主要潜在生态风险因子。进一步因子分析结果显示,发现前3个主成分贡献率分别为:24.056%、22.253%、21.273%,第一主成分反映了Zn的信息,第二主成分主要反映了Cu、部分支配着As、Cd,第三主成分由Ni、Pb组成。

In this paper, Hakanson potential ecological hazard index method is used to study the concentration characteristics of heavy metals such as As, Pb, Cu, Cd, Zn and Ni in the soils of Yishan pasture of Yining County, Xinjiang. The concentration levels of heavy metals in the soils are identified and the levels of potential ecological risks of the pasture are assessed. Furthermore, the main pollution factors are analyzed. The results indicate that the average concentrations of As, Pb, Cd, Cu, Zn and Ni in the soils of the pasture are 11.56 mg · kg-1, 4.85 mg· kg-1, 0.15 mg ·kg-1, 64.80 mg · kg-1, 123.84 mg ·kg-1 and 11.56 mg · kg-l respectively. The average concentrations of Cu and Zn exceed level I of the Environmental Quality Standard for Soils, but those of other heavy metals are below the limits. In 34 sampling points, the over standard rate of Cu and Zn is 97%. In some sampling points, the concentrations of Cd and As exceed the limits. However, from the point of potential ecological risk index, potential ecological risks of the studied region are low. The potential ecological risk of Cd is the highest, followed by Cu, As, Ni, Zn and Pb in a descending order, and Cd is the main factor of potential ecological risks. The results of factor analysis show that contribution rates of the first three principal components are 24.056%, 22.253% and 21.273%. The first principal component reflects the information about Zn. The secondary principal component reflects Cu and partially allocates As and Cd. The third principal component consists of Ni and Pb.