Cadmium and copper sorption in a clayey chernozem soil

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.