赣州市土壤重金属形态分布特征及污染评价

Morphological distribution characteristics and pollution evaluation of heavy metals in the soils of Ganzhou city

以赣州市6大功能区土壤重金属为研究对象,采取表层0~20 cm土壤共50个样品,测定土壤中重金属Pb、Zn、Cu、Cd和Cr含量并分析其来源,采用改进BCR连续提取法进行形态分析,结合次生相与原生相分布比值法、单因子指数法进行污染评价.结果表明研究区土壤中Pb和Cu元素变异系数较大,重金属Zn、Cu和Pb之间相关性显著.通过单因子指数法评价结果可以看出,赣州市6大功能区都受到重金属Cd的重度污染,居民区和工业区受到重金属Cr的轻度污染,交通区受到重金属Pb和Zn的轻度污染.研究区土壤重金属Cd、Cr、Cu、Pb、Zn形态都以残渣态为主,次生相与原生相比值都是小于1的属于无污染.

Taking the heavy metals of soil in the six functional areas of Ganzhou city as the study objects,surfacesoils（0~20 cm） were collected at 50 sites. The contents and origin of of heavy metals（Pb, Zn, Cu, Cd,Cr） were determined and analyzed using the modified Community Bureau of Reference（BCR） sequential extraction procedure.The risks of the heavy metals were evaluated using the ratio of secondary phase and primary phase method and single factor index. The results show that the coefficient of variation of Pb and Cu in the soil of heavy metals in the study areais large, and the correlation between heavy metals Zn, Cu and Pbis significant. The results from the single factor index indicate that soils in six functional areas are affected severely by the pollution of heavy metal Cd;residential and industrial areas are slightly contaminated by heavy metals Cr; traffic area sare slightly contaminated by heavy metals Pb and Zn. The heavy metal speciation in the study area（Cd、Cr、Cu、Pb、Zn）is mainly in the residual state. The soil is not polluted by heavy metals in the study area with the secondary and primary phase value less than 1.