Relationship of Fluoride Concentration to Well Depth in an Alluvial Aquifer in a Semiarid Area

Groundwater of northern Mexico contains high concentrations geogenic fluoride (F−), a contaminant known to affect human health. The origin F− in groundwater this region has been related the weathering rhyolite and other volcanic rocks present alluvium. However, relationship concentration water depth not established. concentrations, pH, total dissolved solids (TSD) were determined for 18 wells within Meoqui-Delicias aquifer 2021. F varied between 0.62 mg L−1 4.84 L−1, 61% exceeded 1.5 guideline. did correlate TDS but correlated well (r = −0.52, p < 0.05). Because less-than-strong correlation coefficient value obtained, diagram vs. was constructed. showed distinct enrichment shallow wells, suggesting that residence time evaporation may be important factors explaining content aquifer. This pattern confirmed after plotting 2003 2006 data same wells. These findings are better understand distribution neighboring alluvial aquifers as elsewhere.