158-13 Impacts of Arsenic and Fluoride Mobilization from experimental Soil Leaching and Water-Rock Interactions as seen in Independence Basin Aquifer, MX

Session: Redox-Driven Nutrient and Contaminant Dynamics in Terrestrial Systems

Presenting Author:

Ashley Aguilar

Authors:

Aguilar, Ashley¹, Kulkarni, Harshad Vijay², Rampe, Elizabeth³, Li, Yanmei⁴, Hernandez, Horacio⁵, González, Lucía Magali Ramírez⁶, Piña, Viridiana⁷, Godet, Alexis⁸, Datta, Saugata⁹

Abstract:

Semiarid environments are characterized by high evaporation rates that favor the accumulation of soluble salts and trace elements in the soil, including toxic trace elements like arsenic (As) and fluoride (F^-). These elements are mobilized during sporadic rainfall events, posing significant risks to the quality of groundwater and to human health. Various environmental factors influence the mobilization of these elements; understanding As and F^- release dynamics within soil and water-rock interactions in semi-arid environments is crucial for assessing groundwater and contamination risk. The complex interactions between water chemistry, environmental conditions, soil and rock composition pose challenges to predicting release and transport. Eluent at varying pH conditions of soil and rock collected from the Independence Basin were analyzed to measure major and trace elemental concentrations. Statistically significant correlations between the measured parameters highlight reactions responsible for mobilization. Linear correlation and Principal Component Analysis (PCA) multivariate analysis were employed to interpret how the sample eluents differed with respect to pH conditions.  Significant inverse relationships were observed between pH and ORP as well as between F^- with As and SO₄²⁺, while ORP had a strong significant relationship with As. Moreover, PCA indicates that in soil leachate and during water-rock interactions, F^- and As are not concurrently mobilized in the same pH conditions, however fluctuations of pH conditions in the soil can be responsible for mobilization. It can be determined from these results that As responds to mobilization from rocks and soils in acidic oxidizing conditions while F^- responded to alkaline slightly oxidizing conditions.

 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11029

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