Mining operations are important causes of environmental pollution in developing countries where mining waste management is not adequate. Consequently, heavy metal(loid)s are easily released into the environment, being a potential risk to human health. This study carries out a Bayesian probabilistic human health risk assessment, related to multi-pathway exposure to heavy metal(loid)s in a gold mining area in Southern Ecuador. Concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn in tap water, surface water, and soil samples, were analyzed to assess the potential adverse human health effects based on the Hazard Index (HI) and Total cancer risk (TCR). Adults and children residents were surveyed to adjust their exposure parameters to the site-specific conditions. Exposure to heavy metal(loid)s resulted in unacceptable risk levels for human health in the two age groups, both carcinogenic (TCR > 1 × 10^-5) and non-carcinogenic (HI > 1) through ingestion of tap water and incidental ingestion of surface water. Sensitivity analysis showed that As concentration in waters and exposure frequency were the main contributors to risk outcome. Exposure to soil via accidental ingestion and dermal contact was below the safety limit, not posing a risk to human health. These findings can provide a baseline for the environmental management of the mining area and indicate the need for further research on As pollution in water and its implications on the health of the inhabitants of mining communities.

Mining environmental liabilities (MEL) are of great concern because of potential risks to ecosystems and human health. In this research, the environmental risk (R_I) related to MEL existing in three artisanal and small-scale gold-mining areas of Ecuador was evaluated. For this purpose, data of 167 MEL including landfills, mining galleries, tailing deposits, and mineral processing plants from Macuchi, Tenguel–Ponce Enriquez, and Puyango mining areas, were analyzed. The risk assessment related to the presence of waste deposits was carried out based on the methodology proposed by the Spanish Geological Survey. Moreover, the procedure outlined in the Environmental Risk Assessment Guide of the Ministry of Environment of Peru for nonwaste deposits was applied. The highest R_I values were identified in Puyango and Tenguel–Ponce Enriquez. Thus, they were both categorized as priority control areas requiring intervention and rehabilitation plans. The MEL that require a high level of intervention include waste deposits and mine entrances associated with potentially toxic elements. Moreover, the point risk maps showed that rivers in the studied areas have a potential pollution risk. This study provides risk levels associated with MEL in mining areas from Ecuador. This information could be used for environmental management and pollution mitigation.

This study assesses the feasibility of reusing tailings from a gold mining area in southern Ecuador in concrete block (CB) manufacturing. For this purpose, physical, chemical, and mineralogical analyses were performed to characterize the tailings. Furthermore, the tailing samples were subjected to the European Standard EN 12457-2 leaching test to assess the potential risk of releasing toxic elements (PTE) into the environment. The CBs were made conventionally and replaced 50% and 70% of the sand with tailings. Lastly, mechanical resistance tests (MRTs) were performed to evaluate the indirect tensile strength, compressive strength, and absorption. The study results show that tailings are feasible as a substitute for sand in manufacturing CBs. Furthermore, the leaching tests complied with the set limit for non-hazardous mining wastes. Regarding the MRT, the CBs made with 50% of tailings were the ones that gave the most favorable results; however, the compressive strength and absorption did not comply with the regulations. In this regard, making CBs with less than 50% tailings is recommended to evaluate their mechanical properties. This study offers an alternative for recycling tailings and contributing to the circular economy.