Temperature induced changes on heavy metal geochemical partitioning and mobility in contaminated and uncontaminated soils

Abstract

The effects of increased soil temperature on metal segregation into different soil geochemical fractions were determined to understand how fire events affect soil metal mobility and bioavailability. Soil samples were heated to 100°C, 200°C, 300°C, and 400°C for 2, 4, and 6 hours respectively and characterised for selected physicochemical properties, mineralogical composition, and metal concentrations in the different geochemical fractions. disappearance of soil OM occurred above 200°C. Increased soil temperature resulted in up to 55% increase and -90% decrease in metal concentrations in soil exchangeable and oxidizable fractions respectively AnN overall increase in soil metal mobilities was observed with metal mobility factors following the order Pb > Cd > Cu > Cr > As > Ni > Zn > Co. Metal Mobility should be considered in the management of fire affected soils because of metal redistributionamong the differentgeochemical fractions which may increase metal enrichment in surrounding environments.