Cadmium Sorption Characteristics of Major Soils of India in Relation to Soil Properties

Concentration of heavy metals in soil solution and their bio-availability are controlled by sorption reactions at soil colloids, which are influenced by soil properties. A study was, therefore, undertaken to compare the sorption characteristics of Vertic Ustochrept, Typic Eutrochrept, Typic Ustochrept, Typic Ustipsamment, Typic Haplustalf and Typic Ustothrent representing five agro-ecologica1 regions of India. Sorption of Cd could be predicted satisfactorily by Freundlich equation and modified Langmuir equation. The conventional Langmuir equation could predict sorption of Cd at lower concentration up to 5 mg L⁻¹ of equilibrium solution. Vertic Ustochrepts and Eutrochrept soils showed maximum-Cd sorption capacity and the least by Ustipsamment, Haplustalf and Ustothent. Such differences in Cd sorption capaoity were related to differences in soil physicochemical properties. Sorption maxima (b) and the Freundlich constant (K_f) of cadmium were positively correlated to CEC, clay, CaCO₃ and pH.