Geogenic Sources and Chemical Controls on Fluoride Release to Groundwater in the Independence Basin, Mexico
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Date
2019-09-18
Authors
LaFayette, Gabrielle
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
High fluoride concentrations in groundwater have been revealed as an environmental health concern. Groundwater in the Independence Basin of Central Mexico reaches over an order of magnitude greater than the World Health Organization limit of 1.5 mg L-1, but sources and geochemical conditions responsible for releasing fluoride into solution are unknown. Objectives of this work determined aquifer rock types containing the greatest amounts of fluoride and investigate how changes in pH and specific conductance affect fluoride release into solution. Solid phase concentrations of fluoride in well drill cuttings displayed no apparent depth dependence, but were greatest within andesitic, alluvium, and conglomerate samples. Large amounts of fluoride were bound with metal oxides/oxyhydroxides in all samples. Batch experiments examining fluoride release from aquifer materials under evolving groundwater conditions revealed that fluoride was released into solution with elevated pH. Results here may be used to better predict fluoride contamination of aquifers.