Simultaneous removal of fluoride and arsenic from drinking groundwater using limestones from Bajío Guanajuatense, Mexico

• Published in: Arabian journal of geosciences 2024, Vol.17 (3), Article 109
• Main Authors: Juárez-Aparicio, Fátima, Morales-Arredondo, José Iván, Armienta Hernández, María Aurora
• Format: Article
• Language: English
• Subjects: Analytical methods; Arsenic; Calcium; Calcium carbonate; Calcium carbonates; Carbonates; Drinking water; Earth and Environmental Science; Earth Sciences; Electron microscopy; Fluorides; Grain size; Groundwater; Health risks; International standards; Limestone; Original Paper; Outcrops; Particle size; pH effects; Removal; Rock; Rocks; Sampling; Saturation; Saturation index; Scanning electron microscopy; Sediment samples; Sediment sampling; Spectroscopy; Water pollution; Water quality; Water wells
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-024-11896-6

Numerous groundwater wells in Mexico exceed the maximum allowable fluoride (F − ) and arsenic (As) drinking water concentration requirements, posing an environmental and health risk to the population that relies solely on these wells for drinking water sources. Since encouraging results have been obtained utilizing native limestones to remove some toxic elements from contaminated water, the ability of the limestone rock outcrop to the south of the Sierra de Guanajuato in Mexico to remove As and F − from groundwater was assessed. A sampling campaign was conducted in the study area, focusing on wells exhibiting elevated concentrations of arsenic (As) and fluoride (F − ) in compliance with international standards. This water was employed in the treatment experiment involving limestone rocks. The rock sampling process involved a reconnaissance campaign covering the study area and outcrop points of limestone rocks. Representative limestone samples were collected and subsequently subjected to mineralogical and geochemical characterization. Using rock samples, synthetic water, and groundwater from contaminated wells in the region, batch experiments were conducted to evaluate the As and F − removal capacity of limestone. The batch testing consisted of water–rock interactions at various times with different samples of limestone rocks, grain sizes, and water containing distinct concentrations of both elements, artificial and groundwater extracted close to the limestones outcrop. The results indicate that the rock with the highest calcium carbonate (CaCO 3 ) content and the smallest grain size (