Chemical speciation of heavy metals in different size fractions of compost from solid urban wastes

Abstract This paper reports “speciation”; of Cu, Zn, Ni, Cr, Pb, Cd, in a compost from solid urban wastes, following a sequential extraction procedure (H2O, KNO3, EDTA). Compost was subdivided into different physical fractions to evaluate the contribution of the various size classes to the heavy metal content. The highest concentrations of heavy metals were found in the finest fraction. Also in this fraction heavy metals are present in extractable forms Cd (86.4%), Ni, Pb, and Zn more than 30% of the total content.