新疆铁门关市绿洲区土壤重金属污染特征及潜在生态风险评价

Characteristics and Potential Ecological Risk Assessment of Soil Heavy Metal Pollution in the Oasis Area of Tiemenguan City, Xinjiang

对铁门关市3 920件表层土壤样品中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn 8种重金属元素含量进行测定,以单因子污染指数法、地累积指数法和潜在生态危害指数法对土壤重金属状况进行评价,对来源进行讨论。结果表明,铁门关市表层土壤中重金属As、Cd、Cr含量与新疆土壤背景值的比值分别为1.17、1.58、1.11。单因子污染指数表明Cd存在0.13%轻度污染,其余重金属元素均为清洁—尚清洁;地累积指数表明Cd轻微、轻度、中度污染比例分别为52.14%、1.33%、0.10%;单项潜在生态危害系数Eri从大到小依次为Cd>Hg>As>Ni>Pb>Cu>Cr>Zn,RI平均值为112.91,绝大部分样品点属于轻微潜在生态危害。相关分析和主成分分析表明,铁门关市表层土壤中Cr、Cu、Ni、Zn主要受到成土母质的影响,Cd受到成土母质和农业生产的共同影响,Cd是研究区农田土壤主要的污染因子,潜在生态风险的贡献较大,农田土壤Cd污染值得关注。

The contents of As,Cd,Cr,Cu,Hg,Ni,Pb and Zn in 3920 surface soil samples from Tiemenguan City were measured.The soil heavy metal status was evaluated by single factor pollution index,geo-accumulation index and potential ecological hazard index,and the sources were discussed.The results showed that the ratios of the contents of heavy metals As,Cd and Cr in topsoil of Tiemenguan City to the background value of Xinjiang topsoil were 1.17,1.58 and 1.11.The single factor pollution index Cd element had 0.13%slight pollution,the others were clean to still clean;the geo-accumulation index heavy metal Cd had slight,mild and moderate pollution proportions of 52.14%,1.33%and 0.10%.The single potential ecological hazard coefficient E i r from high to low in order was Cd>Hg>As>Ni>Pb>Cu>Cr>Zn,and the average value of RI was 112.91,belong to slight ecological hazard.The correlation analysis and principal component analysis showed that topsoil Cr,Cu,Ni and Zn in Tiemenguan City were mainly affected by parent materials,Cd was jointly affected by parent materials and agricultural production,and Cd was the main pollution factor of topsoil in the study area and that had a great contribution to the potential ecological risk of farmland soil,and Cd pollution deserves attention.