Journal article
Diffusive release of uranium from contaminated sediments into capillary fringe pore water
Journal of contaminant hydrology, Vol.140-141(?), pp.164-172
10/2012
Handle:
https://hdl.handle.net/2376/112278
PMID: 23041367
Abstract
Despite remediation efforts at the former nuclear weapons facility, leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford site 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a source for U supply to ground water. We investigated U release from Hanford capillary fringe sediments by packing sediments into reservoirs of centrifugal filter devices and saturating them with Columbia River water for 3 to 84days at varying solution-to-solid ratios. After specified times, samples were centrifuged. Within the first three days, there was an initial rapid release of 6–9% of total U, independent of the solution-to-solid ratio. After 14days of reaction, however, the experiments with the narrowest solution-to-solid ratios showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3−. Geochemical modeling indicated that calcite could precipitate in the narrowest solution-to-solid ratio experiment. After the rapid initial release in the first three days for the wide solution-to-solid ratio experiments, there was sustained release of U into the pore water. This sustained release of U from the sediments had diffusion-limited kinetics.
► Sediments have reacted with river water up to 84days at varying solution-to-solid ratio. ► Initial release of 6–9% of total U, independent of the solution-to-solid ratio ► Narrowest ratios showed a decline in dissolved U concentrations. ► The removal of U from the solution phase was accompanied by removal of Ca and HCO3. ► Wide ratio tests displayed diffusion-limited kinetics of U release from sediment.
Metrics
7 Record Views
Details
- Title
- Diffusive release of uranium from contaminated sediments into capillary fringe pore water
- Creators
- Kenton A Rod - Earth Systems Science Division, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99354, United StatesDawn M Wellman - Earth Systems Science Division, Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99354, United StatesMarkus Flury - Department of Crop and Soil Sciences, Washington State University, Puyallup, WA 98371, United StatesEric M Pierce - Environmental Sciences Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, United StatesJames B Harsh - Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164, United States
- Publication Details
- Journal of contaminant hydrology, Vol.140-141(?), pp.164-172
- Academic Unit
- Crop and Soil Sciences, Department of
- Publisher
- Elsevier B.V
- Identifiers
- 99900547611901842
- Language
- English
- Resource Type
- Journal article