title: Uraninite and fullerene in atmospheric particulates.
abstract: Particulates emitted from coal-burning power plants typically contain very small amounts of uranium (<10 ppm). Because of the extremely low concentrations, the form of the uranium has been unknown. Using a variety of advanced electron microscopy techniques, we have identified for the first time nanocrystals of uraninite, UO2+x, encapsulated in carbonaceous matter (< or = 50 nm) similar to fullerene. We have also identified, for the first time, closely associated fullerenes, C60. The "carbon-caged" nanocrystals of uraninite are protected from the immediate oxidation that would lead to increased mobility of uranium in the environment. Still, the presence of uranium in the very fine fraction of atmospheric particulates provides another pathway for radiation exposure.
authors.affiliation: Department of Nuclear Engineering & Radiological Sciences, Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2104, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Utsunomiya
authors.forename: Keld A
authors.initials: KA
authors.lastname: Jensen
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Keeler
authors.forename: Rodney C
authors.initials: RC
authors.lastname: Ewing
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D003031:Coal; D004784:Environmental Monitoring; D037741:Fullerenes / Q000032:analysis*; D010316:Particle Size; D011210:Power Plants; D014501:Uranium / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D003031:Coal; D037741:Fullerenes; D014501:Uranium