title: Evaluation of hydrochemical changes due to intensive aquifer exploitation: case studies from Mexico.
abstract: The impact of intensive aquifer exploitation has been observed in numerous places around the world. Mexico is a representative example of this problem. In 2010, 101 out of the 653 aquifers recognized in the country, showed negative social, economic, and environmental effects related to intensive exploitation. The environmental effects include, among others, groundwater level decline, subsidence, attenuation, and drying up of springs, decreased river flow, and deterioration of water quality. This study aimed at determining the hydrochemical changes produced by intensive aquifer exploitation and highlighting water quality modifications, taking as example the Valle de Toluca, Salamanca, and San Luis Potosi aquifers in Mexico's highlands. There, elements such as fluoride, arsenic, iron, and manganese have been detected, resulting from the introduction of older groundwater with longer residence times and distinctive chemical composition (regional flows). High concentrations of other elements such as chloride, sulfate, nitrate, and vanadium, as well as pathogens, all related to anthropogenic pollution sources (wastewater infiltration, irrigation return flow, and atmospheric pollutants, among others) were also observed. Some of these elements (nitrate, fluoride, arsenic, iron, and manganese) have shown concentrations above Mexican and World Health Organization drinking water standards.
authors: Centro Interamericano de Recursos del Agua (CIRA), Facultad de Ingeniería, Universidad Autónoma del Estado de México, Cerro Coatepec S/N, 50130 Toluca, Mexico. mvestellera@uaemex.mx
authors: M V
authors: MV
authors: Esteller
authors: R
authors: R
authors: Rodríguez
authors: A
authors: A
authors: Cardona
authors: L
authors: L
authors: Padilla-Sánchez
mesh_terms: D060766:Drinking Water / Q000737:chemistry / Q000592:standards; D004784:Environmental Monitoring; D005459:Fluorides; D060587:Groundwater / Q000737:chemistry*; D008800:Mexico; D009566:Nitrates; D058438:Water Cycle; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data; D060753:Water Quality / Q000592:standards; D014881:Water Supply / Q000592:standards / Q000706:statistics & numerical data*
chemical_list: D060766:Drinking Water; D009566:Nitrates; D014874:Water Pollutants, Chemical; D005459:Fluorides