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Title: Uranium redistribution due to water table fluctuations in sandy wetland mesocosms

In order to better understand the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing a short drying and rewetting period. Concentrations of U in mesocosm effluent increased after drying and rewetting, but the cumulative amount of U released following the dry period constituted less than 1% of the total U immobilized in the soil during the 4 months prior. This low level of remobilization suggests, and XAS analyses confirm, that microbial reduction was not the primary means of U immobilization, as the U immobilized in mesocosms was primarily U(VI) rather than U(IV). Drying followed by re-wetting caused a redistribution of U downward in the soil profile and on to root surfaces. While the U on roots before drying was primarily associated with minerals, the U that relocated to the roots during drying and rewetting was bound diffusely to root surfaces. Results show that short periods of drought conditions in a wetland, which expose reduced sediments to air, may impact U distribution, but these conditions may not cause large releases ofmore » soil-bound U from planted wetlands to surface waters.« less
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0013-936X; 48616; KP1704020
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 49; Journal Issue: 20
American Chemical Society (ACS)
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
Environmental Molecular Sciences Laboratory