resources Article Presence and Distribution of Fluoride Ions in Groundwater for Human in a Semiconfined Volcanic Aquifer Cecilia Judith Valdez-Alegría 1, Rosa María Fuentes-Rivas 2 , José Luis García-Rivas 1, Reyna María Guadalupe Fonseca-Montes de Oca 3 and Beatriz García-Gaitán 1,* 1 Tecnológico Nacional de México/Instituto Tecnológico de Toluca, Av. Tecnológico s/n, Colonia Agrícola Bellavista, Metepec 52149, Estado de México, Mexico;
[email protected] (C.J.V.-A.);
[email protected] (J.L.G.-R.) 2 Facultad de Geografía, Universidad Autónoma del Estado de México, Cerro de Coatepec s/n, Ciudad Universitaria, Toluca 50110, Estado de México, Mexico;
[email protected] 3 Instituto Interamericano de Tecnología y Ciencias del Agua (IITCA), Universidad Autónoma del Estado de México, Unidad San Cayetano, Km.14.5 Carretera Toluca-Atlacomulco, Toluca 50200, Estado de México, Mexico;
[email protected] * Correspondence:
[email protected]; Tel.: +52-722-2087224 Received: 30 April 2019; Accepted: 14 June 2019; Published: 20 June 2019 Abstract: Dental and emaciated fluorosis is derived from the chronic intake of fluoride ions (F−) by consumption of food, tooth products and drinking water from groundwater. Recent reports indicate that in some regions of Mexico, the incidence of fluorosis in temporary and permanent dentitions have increased in recent years. The purpose of the present investigation was to determine the presence and distribution of F− ions in semi-confined aquifers, located in the basins of Lerma-Chapala and Valley of México. Temperature (T), pH, electrical conductivity (EC) and alkalinity were determined in situ, in 27 groundwater wells. The hardness, chloride ions (Cl−), free chlorine (Cl2), total dissolved solids (TDS) and bicarbonates (HCO3−), were determined in the laboratory.