Evaluación del potencial contaminante de los residuos mineros de la Relavera El Tablón, Ecuador

Abstract

CONDITION FOR PUBLICATION OF PROJECT. The present project evaluated the pollution potential of mining tailings deposited in the “El Tablón” Community Tailings Facility, located in the Zaruma-Portovelo mining district, with the objective of characterizing their physicochemical behavior, identifying potentially toxic elements (PTEs) and estimating the associated environmental risks, proposing management recommendations that minimize impacts on the ecosystem and the population. A sampling campaign was conducted, collecting 10 surface samples (0–30 cm) and analyzing pH and electrical conductivity. Leaching tests were also performed following the methodology of the United States Geological Survey (USGS). The concentration of PTEs in solid samples was determined using X-ray fluorescence (XRF), while the leachates were analyzed by ICP-OES at the Soil and Plant Nutrition Laboratory of the Faculty of Life Sciences at ESPOL. The results showed predominantly acidic conditions in 90% of the samples and elevated concentrations of As, Cu, Pb, and Zn, exceeding the maximum permissible limits of Ecuadorian regulations. Samples S01 and S10 were identified as critical points with the highest concentrations of toxic elements. The contamination index classified the site as having a very high level of contamination, indicating a significant environmental risk associated with PTEs mobility. Furthermore, the leaching test results revealed high concentrations of PTEs, especially Zn and Cu, indicating a potential environmental risk. These results highlight the need to implement control, monitoring, and innovation measures in the management of the El Tablón mine tailings to minimize the potential risk to the environment and the population. This project contributes to SDG 9 (Industry, Innovation and Infrastructure) and SDG 12 (Responsible Consumption and Production) by generating crucial information for decision-making in the mining industry. Keywords: mining tailings, pollution index, leaching tests, potentially toxic elements