Simulated In-Situ Immobilization of heavy metals in selected soils of Karnataka

Three soil samples belonging to Alfisols, Vertisols and Ultisols spiked with 100 ppm each of Pb, Ni and Cd was treated with ameliorants like agricultural lime, potassium di-hydrogen orthophosphate (KH₂PO₄) and compost. Sequential extraction procedure was adopted to determine the phyto-available fraction constituting water soluble, exchangeable and carbonate bound metal with the perspective of remediation. Potassium di-hydrogen orthophosphate was the most effective chemical in attenuating Pb as indicated by the lowest phyto-available fraction in soils followed by agricultural lime and compost. For Cd, agricultural lime was superior to other amendments in all the soils. However, among the different ameliorants compost was most efficient in immobilizing Ni in all the soils.