title: Determination of U-236 in sediment samples by accelerator mass spectrometry.
abstract: 236U is produced only by neutron irradiation of uranium and therefore is potentially useful as a marker for anthropogenic uranium in the environment. Accelerator mass spectrometry (AMS) provides a technique for the determination of very low concentrations of actinide nuclides, and has now been applied to the determination of 236U:235U ratios in an intertidal sediment core collected from the North Irish Sea. Combining measurements of the 238U mass concentrations calculated from alpha spectrometry with 238U:235U ratios from ICP-MS and 236U:235U ratios from AMS has allowed the estimation of the mass concentrations of 236U in the sediments. 236U mass concentrations are in the range 10(-8) to 10(-9) g kg-1, and 236U:238U atom ratios in the range from 10(-5) to 10(-6), well above natural baseline levels. Uncertainties based on propagation of measurement errors were less than +/- 10% although +/- 15% is perhaps a more realistic estimate of overall uncertainty.
authors.affiliation: Department of Chemistry, University of Manchester, Manchester, UK M13 9PL. olivia.j.marsden@stud.man.ac.uk
authors.forename: O J
authors.initials: OJ
authors.lastname: Marsden
authors.forename: F R
authors.initials: FR
authors.lastname: Livens
authors.forename: J P
authors.initials: JP
authors.lastname: Day
authors.forename: L K
authors.initials: LK
authors.lastname: Fifield
authors.forename: P S
authors.initials: PS
authors.lastname: Goodall
mesh_terms: D004739:England; D019015:Geologic Sediments / Q000737:chemistry*; D007494:Ireland; D012623:Seawater; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium