METAL SPECIATION AND TOXICITY IN CHROMATED COPPER ARSENATE-CONTAMINATED SOILS

摘要

The influence of composition and physicochemical characteristics of soils on speciation and toxicity of Cu, Cr and As in chromated copper arsenate (CCA)-contaminated soils was assessed. Physicochemical properties of synthetic soils were determined. Cu and Cr partitioning was investigated using a sequential extraction procedure while As speciation was assessed by a modified solvent extraction method. The earthworm Eisenia fetida survival test was used to assess the toxicity of CCA-contaminated soils. Cr and Cu present in organic soils contaminated with CCA were present in less mobile and less bioavailable forms, whereas in mineral soils, the soluble and exchangeable fraction was higher. Arsenic was present principally as As(V). The proportion of As(III) increased with the soil organic matter content. Even though organic soils were more contaminated than mineral soils, they weren't toxic for Eisenia fetida. It was shown that the toxicity of CCA-contaminated soils is related to the partitioning of metals.