Effect of Nano Zero Valent Iron Particles (nZVI) on Mobility and Chemical Forms of Cadmium and Lead in Soil

The mobility and bioavailability of heavy metals in soils is dependent upon redistribution processes between solid and solution phases and among solid-phase components. In order to study the effect of nano zero valent iron (nZVI) on chemical forms of Cd and Pb in soils, an experiment was conducted as a factorial in a completely randomized design in three replications with 4 levels of nZVI (0, 1, 2 and 4 %), 4 levels of incubation time (1, 2, 4 and 8 weeks) and two soils. Chemical distribution of metals in soil was determined using sequential extraction method during mentioned incubation times and the reduced partition index (IR) and mobility factor (MF) of metals were calculated. Application of nZVI significantly (p ≤ 0.01) decreased the exchangeable and carbonate fractions and increased iron and manganese oxide bound fraction in comparison to the control treatment. The IR Values increased and MF values decreased with increasing nZVI levels and incubation time, result in a decrease in MF in soils. It is concluded that addition of nZVI in soil significantly could decrease MF of Cd and Pb in contaminated soils.