Heavy metal immobilisation by limestone filler in soils contaminated by mining activities: Effects on metal leaching and ecotoxicity

Abstract

The leachability and ecotoxicity of potentially toxic elements (PTE) eluting from technosols formed of soils affected by mining activities and limestone filler were evaluated. A total of four contaminated soils affected by opencast mining were selected and mixed with limestone filler at three percentages: 10, 20 and 30 %, providing 12 stabilised samples. Total and soluble PTE content (As, Cd, Cu, Fe, Pb and Zn) was determined in all the samples and the Microtox® bioassay was applied to determine the ecotoxicological effect. The stabilised material had a neutral pH and low soluble PTE concentration. Moreover, the ecotoxicological assay indicated the presence of low toxicity levels in the stabilised samples. The applied bioassay can be considered a good tool for the screening of PTE contamination in areas affected by mining activities, while providing information about possible attenuation processes.