GEOC 125 |
| The 300 Area U(VI) plume at Hanford, WA underlies a 7-10 m vadose zone that was contaminated by infiltrating waste fluids of the North and South Processing Ponds. A series of column and batch experiments combined with modeling, SEM/TEM inspections and EMP, XMP, and CLIFS interrogations were conducted to: i.) Provide insights on molecular level U(VI) solid phase speciation, lithological associations and physical location; ii.) Measure timescales of U(VI) desorption/adsorption reactions under different geochemical conditions; iii.) Develop a combined distributed rate and surface complexation model to predict transport-controlled, U(VI) desorption/adsorption in the contaminated sediments. Results demonstrated that sediment associated U(VI) resided on phyllosilicate coatings and intragrain domains; U(VI) adsorption complexes were present on Fe(III) oxides and phyllosilicates; U(VI) exhibited a complex, time-dependent desorption/adsorption behavior; dissolved inorganic carbon had the greatest impact on U(VI)aq : solid phase interactions; a distributed rate statistical model was used to fit the experimental data. |
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Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
1:30 PM-4:40 PM, Wednesday, 13 September 2006 Moscone Center -- Room 256, Oral
Sci-Mix
Division of Geochemistry |