Remediation of agrosoddy-podzolic soils contaminated with cadmium

Resumo

Results of a long-term field experiment on the remediation of agrosoddy-podzolic soils (Retisols) contaminated with cadmium have been analyzed. The solidification/stabilization method (S/S technology) has been used for the development of remediation technology. Different rates of ameliorants and fertilizers (limestone and phosphorite meals, superphosphate, sodium sulfide, peat, and zeolite) have been studied as ameliorating additives. It has been shown that the efficiency of ameliorating additives in decreasing the mobility of cadmium in the soil depends on their type (the dissolution of ameliorant in water and solubility products of the resulting Cd compounds), application rate, and the time elapsed since the application. In the first year of the experiment, the highest efficiency has been observed for water-soluble forms of ameliorating additives: sodium sulfide and superphosphate. Limestone meal and zeolite have showed the longest aftereffect. The application of all ameliorating additives under study has increased the yield of agricultural crops and reduced their cadmium content down to below the MPC level in most cases, which makes this agronomic practice promising for the remediation of agricultural lands with an elevated content of cadmium.