4. Alteration of Groundwater Hydrochemistry Due to Its Intensive Extraction in Urban Areas from Mexico

The intensive groundwater extraction in Mexico over the years has caused adverse effects, included groundwater level decline, subsidence, and groundwater quality modifications. This study aimed at determining the hydrochemical changes produced by intensive groundwater extraction in Mexico divided into three sectors—north, central, and south of the country. The groundwater quality deterioration due its intensive extraction can be caused by many processes such as, upwelling geothermal or/and mineralized water from deeper aquifers in response to lowering of the potentiometric surface, due to heavy pumping that favors the induction of the flow-through of faults, geological fractures, or deeper wells with a higher concentration of some elements (Fluor, Arsenic, Sodium, Potassium, Nitrates, Sulfates, Chlorides, Vanadium and Boron). Also, the intensive groundwater use favors the infiltration of organic pollutants from the sewerage and percolation of rainwater, resulting in the rapid transport of groundwater and contaminants throughout the aquifer.