Evaluation of heavy metal availability in contaminated soils by a short sequential extraction procedure

A short sequential procedure for the determination of the more readily available metal fractions in soils is presented. These fractions are the mobile (extracted by 0.01 mol l−1 CaCl2) and mobilisable (extracted by DTPA). The method was tested with three soils affected by different anthropogenic sources of pollution: mining, steel factory and traffic emissions. From the results, a potential order of metal availability in these soils is proposed: Cd>Pb>Zn∼Cu>Mn>Ni>Fe∼Cr. Different percentages of available metals, mobile plus mobilisable, were found in the three soils. The method was compared with the results obtained following two widely used extraction procedures. A substantial time saving was achieved by using the method proposed in the present work.