Revealing the Distribution and Bioavailability of Zn, Pb, and Cd in Soil at an Abandoned Zn Processing Site : the Role of Spectrometry Techniques

Abstract

The focus of this study is the potential geochemical hazard in the soil system affected by historical zinc processing in Jaworzno, southern Poland. Total Zn, Pb, and Cd concentrations for soil samples determined by inductively coupled plasma optical emission spectrometry are reported. The modified three-step BCR sequential extraction procedure for analysis of the soil was successfully applied to obtain critical information on the heavy metal bioavailability and toxic impact on the natural environment. Exchangeable-, reducible-, oxidizable-, and residual fractions obtained using the sequential extraction procedure were separated and the heavy metal contents in each fraction were determined using inductively coupled plasma optical emission spectrometry. The results of the partitioning study provide information on the mobility of heavy metals in the soil profiles. Most of the Zn in the topsoil is related to the exchangeable-, reducible- and organic/oxidizable phases. The Zn fractionation in the whole soil profiles looks slightly different, with depletion of exchangeable- and reducible phases and enrichment of residual- and organic fractions. The greatest amount of Pb is associated with the reducible fraction. Cadmium is mainly found in the exchangeable- and reducible fraction. The spectrometry techniques applied are helpful in metal-level assessment and useful for evaluating the fate of contaminants and their bioavailability in soil systems. They show that 40 years since Zn processing ceased, the total concentrations of Zn, Pb, and Cd in the investigated soils are extremely high. Due to the high proportions of the metals in the easily soluble fraction, it is evident that the Jaworzno area has been strongly affected by the historical zinc industry and that the topsoil is heavily contaminated or even toxic.