title: Measurement of Uranium Isotope Ratios in Keratinous Materials: A Noninvasive Bioassay for Special Nuclear Material.
abstract: Hair, toenail, and fingernail are noninvasive, integrative biological monitors routinely used to assess mineral intake.1-4 In this study, we demonstrate the feasibility of distinguishing between exposure to natural, depleted, and enriched U by measuring the (235)U/(238)U, (234)U/(238)U, and (236)U/(238)U ratios in the hair, fingernails, and toenails of occupationally exposed workers and control volunteers. The exposure history of cases and controls to non-natural U was assessed through voluntary self-reporting using a simple questionnaire. The measured U isotope ratios and U concentration in the hair, toenail, and fingernail of cases were compared to a nonexposed control group. No difference was observed in the uranium concentration between the two groups. Significant differences between the cases and the control group were observed in the (235)U/(238)U and (236)U/(238)U isotope ratios but not the (234)U/(238)U. This is the first time that hair, fingernail, and toenail have been demonstrated to be sensitive to occupational exposure to enriched and depleted U, a result with significant implications for proliferation compliance monitoring.
authors.affiliation: University of Missouri - Columbia Research Reactor, 1513 Research Park Drive, Columbia, Missouri 65211, United States.
authors.forename: John D
authors.initials: JD
authors.lastname: Brockman
authors.affiliation: University of Missouri - Columbia Chemistry Department, 601 South College Avenue, Columbia, Missouri 65211, United States.
authors.forename: John W N
authors.initials: JW
authors.lastname: Brown
authors.affiliation: Y12 National Security Complex , Oak Ridge, Tennessee 37830, United States.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Morrell
authors.affiliation: University of Missouri - Columbia Research Reactor, 1513 Research Park Drive, Columbia, Missouri 65211, United States.|University of Missouri - Columbia Chemistry Department, 601 South College Avenue, Columbia, Missouri 65211, United States.
authors.forename: J David
authors.initials: JD
authors.lastname: Robertson
mesh_terms: D001681:Biological Assay; D006197:Hair / Q000737:chemistry*; D006801:Humans; D007633:Keratins / Q000737:chemistry*; D009262:Nails / Q000737:chemistry*; D016273:Occupational Exposure / Q000032:analysis*; D014501:Uranium / Q000032:analysis*
chemical_list: D014501:Uranium; D007633:Keratins