The mobility and accumulation of uranium (U) along the Rio Paguate, adjacent to the Jackpile Mine, in Laguna Pueblo, New Mexico was investigated using aqueous chemistry, electron microprobe, X-ray diffraction and spectroscopy analyses. Given that it is not common to identify elevated concentrations of U in surface water sources, the Rio Paguate is a unique site that concerns the Laguna Pueblo community. This study aims to better understand the solid chemistry of abandoned mine waste sediments from the Jackpile Mine and identify key hydrogeological and geochemical processes that affect the fate of U along the Rio Paguate. Solid analyses using X-ray fluorescence determined that sediments located in the Jackpile Mine contain ranges of 320 to 9200 mg kg −1 U. The presence of coffinite, a U( iv )-bearing mineral, was identified by X-ray diffraction analyses in abandoned mine waste solids exposed to several decades of weathering and oxidation. The dissolution of these U-bearing minerals from abandoned mine wastes could contribute to U mobility during rain events. The U concentration in surface waters sampled closest to mine wastes are highest during the southwestern monsoon season. Samples collected from September 2014 to August 2016 showed higher U concentrations in surface water adjacentmore »
Wildfires and water chemistry: effect of metals associated with wood ash
The reactivity of metals associated with ash from wood collected from the Valles Caldera National Preserve, Jemez Mountains, New Mexico, was assessed through a series of laboratory experiments. Microscopy, spectroscopy, diffraction, and aqueous chemistry measurements were integrated to determine the chemical composition of wood ash and its effect on water chemistry. Climate change has caused dramatic impacts and stresses that have resulted in large-scale increases in wildfire activity in semi-arid areas of the world. Metals and other constituents associated with wildfire ash can be transported by storm event runoff and negatively affect the water quality in streams and rivers. Differences among ash from six tree species based on total concentrations of metals such as Ca, Al, Mg, Fe, and Mn were identified using non-metric multidimensional analysis. Metal-bearing carbonate and oxide phases were quantified by X-ray diffraction analyses and X-ray spectroscopy analyses. These metal-bearing carbonate phases were readily dissolved in the first 30 minutes of reaction with 18 MΩ water and 10 mM HCO 3 − in laboratory batch experiments which resulted in the release of metals and carbonates in the ash, causing water alkalinity to increase. However, metal concentrations decreased over the course of the experiment, suggesting that metals re-adsorb more »
- Award ID(s):
- 1301346
- Publication Date:
- NSF-PAR ID:
- 10083084
- Journal Name:
- Environmental Science: Processes & Impacts
- Volume:
- 18
- Issue:
- 8
- Page Range or eLocation-ID:
- 1078 to 1089
- ISSN:
- 2050-7887
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Publisher's Version of Record
- https://doi.org/10.1039/C6EM00123H
