@article{9c854de811044e97a95cf5f1509c87ad,
title = "Retention and chemical speciation of uranium in an oxidized wetland sediment from the Savannah River Site",
abstract = "Uranium speciation and retention mechanisms onto Savannah River Site (SRS) wetland sediments was studied using batch (ad)sorption experiments, sequential extraction, U L3-edge X-ray absorption near-edge structure (XANES) spectroscopy, fluorescence mapping and μ-XANES. Under oxidized conditions, U was highly retained by the SRS wetland sediments. In contrast to other similar but much lower natural organic matter (NOM) sediments, significant sorption of U onto the SRS sediments was observed at pH<4 and pH>8. Sequential extraction indicated that the U species were primarily associated with the acid soluble fraction (weak acetic acid extractable) and organic fraction (Na-pyrophosphate extractable). Uranium L3-edge XANES spectra of the U-bound sediments were nearly identical to that of uranyl acetate. Based on fluorescence mapping, U and Fe distributions in the sediment were poorly correlated, U was distributed throughout the sample and did not appear as isolated U mineral phases. The primary oxidation state of U in these oxidized sediments was U(VI), and there was little evidence that the high sorptive capacity of the sediments could be ascribed to abiotic or biotic reduction to the less soluble U(IV) species or to secondary mineral formation. Collectively, this study suggests that U may be strongly bound to wetland sediments, not only under reducing conditions by reductive precipitation, but also under oxidizing conditions through NOM-uranium bonding.",
keywords = "Chemical speciation, Retention, Spectroscopy, Uranium, Wetland sediments",
author = "Dien Li and Seaman, {John C.} and Chang, {Hyun Shik} and Jaffe, {Peter R.} and {Koster van Groos}, Paul and Jiang, {De Tong} and Ning Chen and Jinru Lin and Zachary Arthur and Yuanming Pan and Scheckel, {Kirk G.} and Matthew Newville and Antonio Lanzirotti and Kaplan, {Daniel I.}",
note = "Funding Information: This work was supported by Department of Energy, Environmental Management and Office of Sciences . Work was conducted at the Savannah River National Laboratory under the U.S. Department of Energy Contract DE-AC09-96SR18500. Participation of Drs. J.C. Seaman and H.S. Chang in the current study was supported by the Savannah River Ecology Laboratory through a Financial Assistance Award DE-FC09-07SR22506 from DOE to the University of Georgia Research Foundation. Work was conducted at Princeton University under the U.S. Department of Energy Contract DE-SC0006847. Although EPA contributed to this article, the research presented was not directly performed by or funded by EPA and was not subject to EPA's quality system requirements. Consequently, the views, interpretations, and conclusions expressed in this article are solely those of the authors and do not necessarily reflect or represent EPA's views or policies. U L 3 -edge XANES spectral measurements were performed at the Canadian Light Source, which is supported by the Natural Sciences and Engineering Research Council of Canada, the National Research Council Canada, the Canadian Institutes of Health Research, the Province of Saskatchewan, Western Economic Diversification Canada, and the University of Saskatchewan. GeoSoilEnviroCARS is supported by the National Science Foundation's Earth Sciences (EAR-0217473), Department of Energy's Geosciences (DE-FG02-94ER14466), and the State of Illinois . Use of the APS was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. W-31-109-ENG-38. The authors appreciate Savannah Harris and Diana Soteropoulos, University of Georgia, for their assistance with ICP-MS analysis.",
year = "2014",
month = may,
doi = "10.1016/j.jenvrad.2013.10.017",
language = "English (US)",
volume = "131",
pages = "40--46",
journal = "Journal of Environmental Radioactivity",
issn = "0265-931X",
publisher = "Elsevier Limited",
}