Lability of potentially toxic elements in soils affected by smelting activities.

Determination of total concentration of potentially toxic elements (PTEs) in soil is not a reliable tool for evaluating potential exposure risk for humans. PTE lability (EDTA, SBET and solution extraction) and chemical speciation (BCR sequential extraction) were investigated for Pb, Cd, Cu, and Zn, as well as how these could be affected by flooding in soils polluted by smelting activities. The flooding experiment was performed in pots from which soil solution was extracted at different time intervals using Rhizon Moisture Samplers. After experiments, the soil was again subjected to the previous extractions (EDTA, SBET, and BCR) in order to reveal the changes which occurred during anoxia. From the results we can conclude that PTE lability is very high and flooding caused the increase in their mobility up to 100% (for bioaccessible Pb). The experiment demonstrated that temporary reducing conditions can increase the risk of contaminants passing to other environmental compartments and the food chain.