新疆奎屯垦区土壤重金属风险评价

Assessment of Ecological Risk of Heavy Metals in Soils in Kuitun,Xinjiang

采用网格法采样,对新疆奎屯垦区3个团场土壤中As、Pb、Cu、Cd、Cr和Ni含量进行了测定,系统分析了该地区土壤重金属的含量水平、潜在生态风险程度、主要污染因子和污染来源。结果表明:奎屯垦区土壤重金属As、Pb、Cd、Cu、Cr、Ni的平均值分别为20.21 mg kg-1、35.91 mg kg-1、0.40 mg kg-1、27.18 mg kg-1、77.02 mg kg-1、39.31 mg kg-1,均没有超过国家土壤环境质量二级标准,但As、Cd有个别样点超标。各元素平均含量值均超过新疆土壤背景值,其中Cd、As、Pb最为显著,呈现出累积趋势。各重金属潜在生态风险由高至低顺序为Cd>As>Pb>Ni>Cu>Cr,其中Cd为主要潜在生态风险因子。进一步相关分析和因子分析结果显示,各元素的来源可分为两类,Cd、Pb和As为一类,来源主要受各种人为活动影响,Cu、Cr、Ni为一类,来源主要与成土母质有关。

Hakanson potential ecological risk index techniques, correlation analysis, principal component analysis were applied to estimate the characteristics of heavy metal combined contamination （As, Pb, Cu, Cd, Cr and Ni）. The content, The degree of potential ecological risks, the main factors of environment pollution and sources of the heavy metals in soil of Kuitun were analyzed. The results showed that the average concentrations of the As, Pb, Cd, Cu Cr and Ni in soil were 20.21 mg kg^-1, 35.91 mg kg^-1, 0.40 mg kg^-1, 27.18 mg kg^-1, 77.02 mg kg^-1, 39.31 mg kg^-1. They were lower than the secondary standards of the national soil environment; but the average concentrations of the heavy metals were more than background values of soil in Xinjiang. Especially, the Cd, As and Pb showed a net cumulative trend. The order of pollution extents was Cd 〉 As 〉 Pb 〉 Ni 〉 Cu 〉 Cr. Cd was the main factor of potential ecological risks. The results of correlation analysis and factor analysis showed that the sources of these elements could be divided into two categories： the Cd, Pb and As as one class, the Cu, Cr and Ni as another class. The Cd, Pb and As levels were associated with anthropogenic activities, whereas Cu, Cr and Ni were controlled by the parent materials.