Modelling of Heavy Metal Mobility in Delhi Soils before and after Remediation with Green Amendment Rock Phosphate using Sequential Extraction,TCLP and PBET

The particular behaviour and fate of trace metals like lead (Pb) are governed by a range of different physico-chemical processes and thereby the resulting different physico-chemical forms rather than by its total concentration. These dictate its availability and mobility in the soil or sediment system. In the solution phase, the chemical form of a lead determines the biological availability and chemical reactivity (sorption/desorption, precipitation/dissolution) towards other components of the system. Sequential methods primarily are intended to understand the particular environmental behaviour of lead, present in a variety of forms and in a variety of matrices. After applying cost effective green remediation technique of chemical immobilization by phosphate amendment the mobility factor of lead reduced considerably. This has been inferred from the sequential extraction studies as the lead has moved from the exchangeable sites to the residential sites. The results have been further confirmed by PBET and TCLP studies.