The redistributions of Pb, Zn, Cu and Cd were determined using the sequential extraction procedure of the optimized European Community Burean of Reference (BCR) before and after extraction.

• 萃取后,Pb、Cu和Cd离子随着土壤柱深度的增加,容易被土壤颗粒吸附,使萃取效果也随之降低,尤其Cu表现明显。 Zn的萃取效果则与土壤柱深度不呈现出相关性。