Cadmium and copper sorption in a clayey chernozem soil

Abstract

The wastes used to amend soils sometimes have high concentrations of metals such as cadmium (Cd2+) and cooper (Cu2+). To determine the capacity of soils to retain these metals, the sorption capacities of different mine soils with and without reclamation treatments (tree vegetation and waste amendment) for Cd2+ and Cu2+ in individual and competitive situations were evaluated using the batch sorption technique. The untreated settling pond soil had low capacity for Cd2+ and Cu2+ retention. The site amended with wastes (sewage sludges and paper mill residues) increased the sorption capacity; most probably because of the higher concentrations of soil components with high retention capacity such as carbon and clay fraction. We can conclude that, despite the possible additions of Cd2+ and Cu2+ from wastes to degraded soils, sewage sludges and paper mill residues have a high sorption capacity that would prevent the metals from being in a mobile form.