title: A comparison of fallout (236)U and (239)Pu uptake by Australian vegetation.
abstract: The isotopes (236)U and (239)Pu, both produced during nuclear weapons tests carried out in the 1950s and 1960s, are present in the environment and may be used as tracers for soil erosion studies. Although these radionuclides occur only at ultra-trace levels in nature, they can be readily measured by accelerator mass spectrometry with the 14UD heavy ion accelerator at the Australian National University. We have analysed a series of vegetation samples for their (236)U and (239)Pu concentration and compared the results with those found in the surrounding soil. (236)U could be measured in all collected samples whereas (239)Pu could not be detected in several vegetation samples due to its very low concentration, although it was readily detectable in the soil. We find that, relative to plutonium, (236)U is preferentially taken up by plants with enrichment factors ((236)U/(239)Pu)veg/((236)U/(239)Pu)soil that range between 7 and 52 in the present study.
authors.affiliation: Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia. Electronic address: michaela.froehlich@anu.edu.au.
authors.forename: M B
authors.initials: MB
authors.lastname: Froehlich
authors.affiliation: Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia; Faculty of Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: M M A
authors.initials: MM
authors.lastname: Dietze
authors.affiliation: Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia.
authors.forename: S G
authors.initials: SG
authors.lastname: Tims
authors.affiliation: Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia.
authors.forename: L K
authors.initials: LK
authors.lastname: Fifield
mesh_terms: D020958:Australian Capital Territory; D010944:Plants / Q000378:metabolism*; D011005:Plutonium / Q000378:metabolism*; D011834:Radiation Monitoring; D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive / Q000378:metabolism*; D014501:Uranium / Q000378:metabolism*
chemical_list: D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive; D014501:Uranium; D011005:Plutonium
keywords: (236)U; AMS; Accelerator mass spectrometry; Plutonium; Soil; Vegetation