Mobilization of antimony and arsenic in soil and sediment samples -: Evaluation of different leaching procedures

This study aims to evaluate the performance of different leaching schemes with respect to the mobilization of antimony and arsenic from polluted samples collected at different sites in Mansfeld District, Germany. Besides the elution by water the leaching by artificial acidic rain and by two different schemes of sequential extraction were employed for estimation of the mobilization of antimony and arsenic. The samples were characterized by X-ray fluorescence analysis for their total concentration of metalloids, metals and main constituents. It was found that both antimony and arsenic show little mobilization with de-ionized water as well as artificial acidic rain in single step batch procedures (<= 0.13% of the total content). Although the percentage leached is very low, the concentrations in the resulting solutions are of ecotoxicological relevance. BCR procedure indicate a very strong binding of Sb and of As in the samples. Less than 20% of the total content can be leached in sum in all leaching steps, of it most under strongly oxidizing conditions. This scheme seems not suitable for a detailed investigation of possible mobilization processes under environmental conditions for the metalloids under investigation. The four-step extraction procedure by Wenzel et al. gives a more detailed pattern of the binding of antimony and arsenic. This procedure was found to be a suitable scheme for evaluating the possible mobilization processes from the samples contaminated by ore processing waste, especially by change through other ions or under reducing conditions.