title: Uranium Redistribution Due to Water Table Fluctuations in Sandy Wetland Mesocosms.
abstract: To understand better the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated sandy 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 XANES 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 rewetting caused a redistribution of U downward in the soil profile and to root surfaces. Although 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. Results show that short periods of drought conditions in a sandy wetland, which expose reduced sediments to air, may impact U distribution without causing large releases of soil-bound U to surface waters.
authors.affiliation: Princeton University , Princeton, New Jersey 08540, United States.
authors.forename: Emily R
authors.initials: ER
authors.lastname: Gilson
authors.affiliation: Princeton University , Princeton, New Jersey 08540, United States.
authors.forename: Shan
authors.initials: S
authors.lastname: Huang
authors.affiliation: Princeton University , Princeton, New Jersey 08540, United States.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Koster van Groos
authors.affiliation: U.S. EPA , Cincinnati, Ohio 45268, United States.
authors.forename: Kirk G
authors.initials: KG
authors.lastname: Scheckel
authors.affiliation: Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Odeta
authors.initials: O
authors.lastname: Qafoku
authors.affiliation: Pace Analytical Energy Services , Pittsburgh, Pennsylvania 15238, United States.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Peacock
authors.affiliation: Savannah River National Laboratory , Aiken, South Carolina 29808, United States.
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Kaplan
authors.affiliation: Princeton University , Princeton, New Jersey 08540, United States.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Jaffé
mesh_terms: D001345:Autoradiography; D003890:Desiccation; D019015:Geologic Sediments / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D011851:Radioactivity; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D053833:Wetlands
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium