title: Fate of 90Sr and U(VI) in Dounreay sediments following saline inundation and erosion.
abstract: There is concern that sea level rise associated with projected climate change will lead to the inundation, flooding and erosion of soils and sediments contaminated with radionuclides at coastal nuclear sites, such as Dounreay (UK), with seawater. Here batch and column experiments were designed to simulate these scenarios and sequential extractions were used to identify the key radionuclide solid phase associations. Strontium was exchangeable and was mobilised rapidly by ion exchange with seawater Mg(2+) in both batch and column experiments. In contrast, U was more strongly bound to the sediments and mobilisation was initially limited by the influence of the sediment on the pH of the water. Release was only observed when the pH increased above 6.9, suggesting that the formation of soluble U(VI)-carbonate species was important. Under dynamic flow conditions, long term release was significant (47%), but controlled by slow desorption kinetics from a range of binding sites.
authors.affiliation: Biogeochemistry and Environmental Analytical Chemistry Group, Biogeochemistry Research Centre, Plymouth University, Plymouth PL4 8AA, UK. jane.eagling@plymouth.ac.uk
authors.forename: Jane
authors.initials: J
authors.lastname: Eagling
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Worsfold
authors.forename: William H
authors.initials: WH
authors.lastname: Blake
authors.forename: Miranda J
authors.initials: MJ
authors.lastname: Keith-Roach
mesh_terms: D057231:Climate Change; D004784:Environmental Monitoring; D055868:Floods; D019015:Geologic Sediments / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000737:chemistry; D013058:Mass Spectrometry; D012588:Scintillation Counting; D012606:Scotland; D012623:Seawater / Q000032:analysis / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D013324:Strontium / Q000032:analysis / Q000737:chemistry*; D013326:Strontium Radioisotopes / Q000032:analysis / Q000737:chemistry; D014501:Uranium / Q000032:analysis / Q000737:chemistry*; D014872:Water Movements; D014875:Water Pollutants, Radioactive / Q000032:analysis / Q000737:chemistry*
chemical_list: D013326:Strontium Radioisotopes; D014875:Water Pollutants, Radioactive; D014501:Uranium; D008274:Magnesium; D013324:Strontium
keywords: Porewater salinization; Radioactive waste; Radionuclide transport; Release kinetics; Strontium-90; Uranium