Spectroscopic characterization of uranium in evaporation basin sediments
Evaporation ponds in the San Joaquin Valley (SJV), CA, used for the containment of irrigation drainage waters contain elevated levels of uranium (U) resulting from the extensive leaching by carbonate-rich irrigation waters of the local agricultural soils that contain low levels of naturally-occurring U. The SJV ponds are subjected to changes in redox chemistry with cycles of drying and flooding. Past studies have shown that U in the SJV Pont 14 surface sediments is present as mostly the oxidized and soluble form, U(VI). However, the authors were uncertain whether the U in the soil was only present as a U oxide of mixed stoichiometry, such as U{sub 3}O{sub 8(s)} (pitchblende) or other species. Here they present characterization information, which includes wet chemical and in situ spectroscopic techniques (X-ray absorption near-edge structure (XANES) and low temperature time-resolved luminescence spectroscopies) for samples from two SJV Pond sediments. Surface sediments from SJV Pont 16 were characterized for average oxidation state of U with XANES spectroscopy. The wet chemical extractions and in situ spectroscopic techniques provided fundamental and basic knowledge about the fraction of U(IV) to U(VI), the speciation of luminescent U(VI), and the susceptibility of the sediment U species to leaching.
- Research Organization:
- Univ. of Georgia, Aiken, SC (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC09-96SR18546; FG02-92ER14244
- OSTI ID:
- 20062614
- Journal Information:
- Geochimica et Cosmochimica Acta, Vol. 64, Issue 9; Other Information: PBD: May 2000; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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