BCR法在污染农田黑土重金属形态分布研究中的应用

通过对东北地区污染农田黑土剖面的取样调查分析，对重金属Cd、Ph、Cu、Zn在农田黑土中的污染状况及其迁移特征进行了对比研究，并就BCR（the Community Bureau of Reference）连续提取法在农田土壤重金属污染评估中的应用进行了探讨。结果表明，重金属的迁移率大小依次为：Cd〉Cu〉Pb〉Zn，Cd的酸可溶态占全量的比率高于其它重金属。Pb的酸可提取态浓度随土壤深度增加而增大，公路附近土壤中PL、Cu及城市郊区土壤中Cd、Pb和Zn的氧化物结合态含量均随土壤深度的增加而升高，已存在向下迁移的趋势。4种重金属有机结合态在采样区土壤中基本都表现为耕层高于非耕层。研究表明，应用BCR连续提取法有助于确定土壤重金属污染以及重金属向下迁移状况，借助该法可以有效、可靠地对土壤重金属污染进行评估。

Application of Sequential Extraction of BCR to Forms Distribution of Heavy Metals in Polluted Black Soil

State and mobility of Cadmium(Cd),Lead(Pb),Copper(Cu) and Zinc(Zn) pollution were investigated at different depths of polluted farmland black soil,and the application of the BCR sequential extraction was studied.The results showed that the mobility order of the heavy metals is Cd>Cu>Pb>Zn.Cadmium occurred more abundantly in mobile fraction than did the other elements.The concentration of Pb in the acetic acid extractable fraction,as well as the concentration of hydroxide-bound fraction of Pb,Cu near the roadsides and Cd,Pb and Zn in the suburb all increased with the depth of profiles,indicated some downward movement of heavy metals.The concentrations of organically-bound fraction of the heavy metals in most of sampling area were all higher in the plow layer,which indicated the accumulation of heavy metals of this fraction in the surface layer.The results showed that application of sequential extraction of BCR was useful in assessing the pollution and movement of heavy metals in soil.