冶炼厂周边土壤重金属污染范围的界定与不确定性分析

在浙江省富阳市某冶炼厂周边以网格法采集了147个表层土壤样品,测定了铜、锌、铅和镉总含量。运用组合预测法(普通块状克里格法和三角网格插值法)预测了研究区各种重金属含量的空间分布,又运用指示克里格法预测了研究区各种重金属的污染概率;再分别依据土壤污染临界值(土壤环境质量标准)和污染概率的临界值(50%)来界定各种重金属的污染范围。本研究将基于两种方法的界定结果相对比来综合界定污染范围,并将污染土壤重金属污染状况分为污染、未污染和不确定。综合界定结果表明,研究区分别有71.7%、80.0%、3.0%、83.1%的区域土壤被重金属Cu、Zn、Pb、Cd所污染,不能被确定是否被重金属Cu、Zn、Pb、Cd所污染的区域分别占20.8%、10.5%、12.5%和10.9%。

Identification and uncertainty analysis of scope of heavy metal pollution in the vicinity of secondary copper smelteries

One hundred and forty seven surface soil samples were collected from a contaminated site in Fuyang, Zhejiang Province for determination of concentrations of total copper, zinc, lead and cadmium in the soil. Spatial distribution of the four heavy metals in the study area was predicted using the combined prediction method (ordinary block kriging and triangular irregular network interpolation), and pollution probabilities, too, using the indicator kriging. Once again based on their respective soil pollution thresholds (i.e. soil environmental quality standard), and pollution probability thresholds (i.e. 50%), pollution scopes of the heavy metals were defined separately. The two results were compared for integrated definition of scopes of their pollution. In light of the severity of the pollution, heavy metal pollution of the studied region was sorted into "Polluted", "Unpolluted" and "Undefined". Results of the integrated definition show that 71.7%, 80.0%, 3.0%, and 83.1% of the soils in the area were polluted by Cu, Zn, Pb and Cd, and 20.8%, 10.5%, 12.5% and 10.9% were undefined whether they were polluted by Cu, Zn, Pb and Cd or not, respectively.