Adsorption-Desorption Behaviour of Lead in Soils Amended with Different Organic Materials

A laboratory experiment was conducted to study the adsorption-desorption behaviour of lead in sandy loam Typic Haplustept and sandy Typic Ustipsamment amended with different organic materials.The results indicated that the Pb adsorption was concentration-dependent in both the soils. Relatively higher amounts of added Pb were adsorbed (4.70–4.75 mg 100g⁻¹) in sandy loam than in sandy soil (3.65–4.05 mg 100g⁻¹), amended with different organic materials at lower concentration of the former in the equilibrium solution. The highest amount of 4.75 mg Pb 100g⁻¹ was adsorbed in the FYM-amended soil. The desorption of Pb increased with increased concentration of Pb in equilibrium solution. Higher amount of Pb was desorbed by CaCl₂ from the samples where more Pb was retained in soil. More desorption was observed from sandy soil than that from sandy loam soil. However, complete desorption did not take place by 0.002 M CaCl₂ in any case. Thus amendment of a soil with any type of organic material reduces the desorbability of Pb from the soil which suggests less Pb availability.