Lead (Pb) is a toxic metal associated with several health disorders. The mining and Pb battery industry are related to Pb increase in air, water, and soil. Mexico is an important worldwide Pb producer; however, reviews on environmental Pb contamination in Mexico are insufficient. Since Pb remains stable in soil and its concentration is an indicator of Pb exposure, this systematic review focused on reports of Pb concentrations in soil from Mexico published in 2010–2023. The retrieved reports were ordered, and contamination grade and health risk were estimated for location. From 36 retrieved reports, 24 were associated with mining Pb pollution, while a unique report mentioned the battery industry. The publications evaluated mining (13), agricultural (11), and residential (16) soils. Pb concentrations in soil were higher than the allowed limits in more than half of the reports. According to the Pb concentrations in soil, the locations evaluated in Mexico presented a contamination grade from heavily contaminated to extremely contaminated and health risks results suggested severe hazards, particularly for children. This work can guide other researchers to identify potentially contaminated but understudied Mexican locations.
21 November 2016 in International Journal of Environmental Science and Technology
This paper provides an overview of the impacts of mining-related environmental liabilities on humans, soils, sediments, surface water and groundwater across various mining districts in Zacatecas, Mexico. An analysis has been carried out on the areas of the state most affected by the presence of potentially toxic elements (PTEs) such as arsenic, lead, cadmium, copper, chromium and zinc, identifying priority areas for environmental assessment and remediation. Likewise, a review of the concentrations of PTEs reported in different environmental matrices of the state’s mining areas with the presence of environmental liabilities was carried out, most of which exceed the maximum permissible limits established by Mexican and international regulations, generating an environmental risk for the populations near these districts due to their potential incorporation into the food chain. Additionally, this study explores research focused on the biostabilization of PTEs using microorganisms with specific metabolic activities. Phytoremediation is presented as a viable tool for the stabilization and elimination of PTEs, in which endemic plants from arid–semi-arid climates have shown favorable results in terms of the phytostabilization and phytoextraction processes of the PTEs present in mining waste.
Mine wastes from the La Aurora mine in the state of Guanajuato were generated by the flotation process and placed in four tailing dumps on the local stream while the plant operated. Given that these wastes contain toxic elements, it is important to establish their impact on the quality of several surrounding natural sources of water that are considered potential drinking water supplies. This study identified four water source types, in which the contents of arsenic (As), mercury (Hg), and thallium (Tl) were exceeded, according to international guideline values for drinking water quality. The first type of aqueous sample corresponded to leachates produced by rainwater infiltration in tailings and water–mineral waste interactions. The second type corresponded to surface water along the Xichú and La Laja Streams, and the third and fourth types involved two groundwater well samples and spring samples, respectively. The Chiquito Stream was used as a reference area that had not been impacted by the mine wastes. The isotopic signatures associated with δ34Ssulfate and δ18Osulfate compositions from the El Ojo de Agua spring are similar to those of the Santa María River and are different from those of the mine waste leachates. This study shows evidence of the presence of As in the El Ojo de Agua spring, which results from dissolution of secondary mineral phases that were produced by alteration of the mine wastes, which then migrated along the Xichú Stream system until reaching the spring. These As-bearing fine particles are prone to dissolution when in contact with this water source. Principal component analysis revealed that the observed As, Tl, and Hg can be attributed to weathering of the mine wastes. However, the results suggest that a natural contribution of these elements could be associated with rainwater–igneous rock interactions.