Effects of Incubation and Phosphate Rock on Lead Extractability and Speciation in Contaminated Soils

Abstract

Lead distribution in 11 contaminated soils among five physical size fractions was studied. Lead was present in elevated concentrations in these soils, ranging from 198 to 12 523 mg kg -1 . Although Pb in these soils was randomly distributed among the five size fractions studied, it was slightly concentrated in the silt and clay ( < 53 μm) fraction with some exceptions. Several single chemical extractants were used to evaluate Pb availability in the contaminated soils. The effects of incubation and phosphate rock on Pb availability were also investigated. Significant amounts of Pb were extracted with all the extractants. The extractability increased in the order: H 2 O < Ca(NO 3 ) 2 < HOAc