Comparative Assessment of Leaching Tests According to Lixiviation and Geochemical Behavior of Potentially Toxic Elements from Abandoned Mining Wastes

The release of potentially toxic elements (PTEs) from abandoned mining waste (AMW) is generally assessed with leaching tests. The United States, Mexico, and Spain's geological surveys respectively use leaching tests USGS FLT, NOM-141-SEMARNAT-2003, and EN-12457-2 to assess the potential water pollution from AMW. However, to facilitate preliminary hazard assessment of the potential leaching, especially for daily practice at sites with a large amount of recorded AMW, a comparative assessment of these widely used leaching tests can be helpful. The present research covers this knowledge gap by evaluating the geochemical leaching behavior of As, Ba, Cu, Pb, and Zn, by using these leaching tests in different types of AMW. The results suggest that these methods show slight differences in saturation indices, pH, specific conductance, redox potential, and released PTEs that can be mainly imputed to the contact time. Despite these differences, the findings suggest that the lixiviation patterns from the analyzed methods are comparable, and allow the same conclusions to be reached regarding the potential hazard of the AMW as a function of the solubility of the PTEs.