Temporal variation and co-occurrence of fluoride and arsenic in aquifers of the central semi-arid region of Chihuahua, Mexico


The objectives of this study were, to evaluate the change in concentrations of Arsenic (As) and Fluoride (F) in three aquifers located in the central semi-arid region of Chihuahua, at three different times within a seven year period. The As content in rock, sediment, and groundwater samples was first determined in 2004; later on, in 2007 and 2010, the content of As and F in groundwater were measured. In all three sampling episodes some wells had consistently As concentrations above 0.025 mg/L. The F concentration surpassed the Mexican limit values of 1.5 mg/L in 77% of the measured wells. The surrounding rocks contained enough As and F to support a geogenic origin of these contaminants and their higher concentrations within the rhyolites indicates a possible chemical association to these volcanic rocks. A correlation between As and F suggests a co-occurrence of these two contaminants (r 2 = 0.52, P < 0.001). The observed variations on the three-year concentrations of As and F in the three measured events indicate a stable evolution for As, and a dynamic increase evolution in the case of F. © 2012 Taylor & Francis Group.

Document Type

Conference Proceeding

Publication Date


Journal Title

Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment