Environmental toxicity assessment of mining waste from an abandoned Zn-Pb mine

Purpose. To assess the impact of mining waste on the heavy metal content of water surfaces, plants, and topsoil near the tailings dam of a Zn-Pb mine using both biotests and analytical methods. Methodology. A battery of microbiotests on different animal and plant species was carried out, making it possible to evaluate the toxic effect of residues and surrounding soils on living organisms. Furthermore, the possible relationship between the observed toxicity and the results of the physicochemical analysis of the samples was studied. Findings. The tests showed that the topsoil in contact with the tailings dam is slightly toxic to the living organisms used while the mining tailings are toxic or even very toxic. The heavy metal content of the samples is particularly high for Fe, Zn, Pb and Cu. The correlation of physic-chemical parameters and the results of microbiotests using the principal components analysis (PCA) and the multiple correspondence factor analysis (MCFA) indicate that the toxicity of tailings and the surrounding topsoil can be associated with anthropogenic mining activity. Originality. The study aimed to assess the impact of mining waste on the heavy metal content using biotests and analytical methods. The evaluation considers the concentrations of the samples (highly concentrated samples and samples after dilution) and the different phases of exposure (solid, liquid) for a more detailed assessment of the potential toxicity of the samples. Practical value. It is important to conduct a comprehensive assessment of mining waste and the risks it may pose to humans and the environment in order to develop an adequate rehabilitation plan.