Trace Element Speciation in Contaminated Soils Studied by Atomic Absorption Spectrometry and Neutron Activation Analysis

Abstract

Abstract Leachable forms of the elements Ag, Cd, Co, Cu, Fe, Li, Mn, Ni, Pb, Sb, and Zn were studied in soils with increased levels of the elements Ag, Cd, Pb, Sb, and Zn due to contamination by sewage sludges from a metallurgical plant as well as in control soil samples. The total element contents, except for Cu, Li, and Pb were determined by INAA. For quality assurance purposes, the reference materials IAEA Soil-5 and IAEA Soil-7 were also analyzed. Partitioning of the elements was studied by AAS and partly by NAA using a multi-step sequential leaching procedure designed to divide elements into five fractions: exchangeable metals, metals bound to carbonates, metals bound to Fe-Mn oxides, metals bound to organic matter, residual metals. Of the metals studied, cadmium appeared to be most readily solubilized from the soil samples. Differences in leachabilities of the elements Co, Fe, and Zn from unirradiated and reactor irradiated samples are discussed.