Assessment of metal extraction, distribution and contamination in surface soils by a 3-step sequential extraction procedure

A 3-step sequential extraction procedure was used in order to assess the environmental risk of Cu, Ni and Zn in contaminated soils. The non-residual fraction was the most abundant pool for Cu in all soils, which means that this metal is highly available in these soils. Ni was mostly concentrated in the residual fraction. Zn was found in all the fractions but its distribution pattern was different in each soil. Individual and global contamination factors were calculated from the non-residual and residual contents and their values allowed us to classify the soils according to their environmental risk.