Application and assessment of sequential extraction for trace metal characterization of contaminated soil

grantor: University of TorontoThe operational speciation of selected trace metals in several contaminated Toronto area soils was determined by a modified BCR sequential extraction procedure. These results were verified through the use of standard reference soils, and suggested potential approaches to remediation. For a fill material taken from downtown Toronto and sediment from Toronto Harbour, metal partitioning behaviour conformed with the theory and anecdotal evidence in the soil chemistry literature: Cd was highly mobile, while Cu and Pb were primarily associated with organic matter, and Zn was distributed across all soil fractions. Soil from an abandoned metals recycling operation had unusual physical characteristics, and the trace metals within were largely non-extractable. Using radiotracer techniques, redistribution of Cd and Zn during the sequential extraction was directly evaluated for the first time. Although measurable readsorption of these elements occurred, the phenomenon was not as extreme as previously suggested.M.A.Sc