15 Environmental Geochemistry and Health Impacts

This session welcomes research on contaminant occurrence, fate and transport, and impacts on human and environmental health. Interdisciplinary contributions with implications for environmental remediation and natural resources management are encouraged.

Monday, 18 May 2026
1:30 PM - 4:00 PM
Alvarado G

Citric Acid Aided Metal Mobility in Fine Fractions of Solids from a Uranium Mining Legacy Site

Paper number: 15-1
Program: Technical Sessions
Time: 1:35 PM – 1:55 PM

Authors

Abstract

The Jackpile Mine, a former uranium (U) mine and current Superfund site in New Mexico, was active from the early 1950s through the 1980s and has been partially remediated. Heavy metal mobility in the fine fractions of solids (<63 µm) in and around this site is not well understood. Here, we reacted the fine fractions from surface accumulations and mineralized deposits with citric acid and water to understand the desorption and dissolution of metals in these environmental systems. Sample composition had a large effect on the mobility of metals – thermogravimetric analysis of the two sample types shows the mineralized deposits contain 10.9% organic matter (OM) and 0.4% carbonate by weight, and the surface accumulations contain a maximum of 3% OM and 4.8% carbonate by weight. We found that the carbonate buffers the citric acid, making it difficult to lower pH enough to cause rapid dissolution. The time-series reactions with a 10 mM citric acid solution at pH 5.5 reveal that the primary mechanism for aluminum (Al), and iron (Fe) mobility is dissolution, but calcium (Ca) and potassium (K) are controlled by desorption. Uranium has both desorption and dissolution processes at work. Inductively-coupled plasma – mass spectroscopy (ICP-MS) confirms that concentrations of U after 24 hours of reaction with the mineralized deposit and citric acid are 47.2% of the total acid-digested concentration. This reaction shows that U in the mineralized deposit can be easily mobilized by a weak organic acid, like one found at plant root-soil interfaces Results from this paper have important implications for both bioremediation by plant and fungi and local agriculture.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410619

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