title: Analysis of 129I in the soils of Fukushima Prefecture: preliminary reconstruction of 131I deposition related to the accident at Fukushima Daiichi Nuclear Power Plant (FDNPP).
abstract: Iodine-131 is one of the most critical radionuclides to be monitored after release from reactor accidents due to the tendency for this nuclide to accumulate in the human thyroid gland. However, there are not enough data related to the reactor accident in Fukushima, Japan to provide regional information on the deposition of this short-lived nuclide (half-life = 8.02 d). In this study we have focused on the long-lived iodine isotope, (129)I (half-life of 1.57 × 10(7) y), and analyzed it by accelerator mass spectrometry (AMS) for surface soil samples collected at various locations in Fukushima Prefecture. In order to obtain information on the (131)I/(129)I ratio released from the accident, we have determined (129)I concentrations in 82 soil samples in which (131)I concentrations were previously determined. There was a strong correlation (R(2) = 0.84) between the two nuclides, suggesting that the (131)I levels in soil samples following the accident can be estimated through the analysis of (129)I. We have also examined the possible influence from (129m)Te on (129)I, and found no significant effect. In order to construct a deposition map of (131)I, we determined the (129)I concentrations (Bq/kg) in 388 soil samples collected from different locations in Fukushima Prefecture and the deposition densities (Bq/m(2)) of (131)I were reconstructed from the results.
authors.affiliation: Faculty of Science, Gakushuin University, Mejiro 1-5-1, Toshima-ku, Tokyo 171-8588, Japan. Electronic address: yasuyuki.muramatsu@gakushuin.ac.jp.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Muramatsu
authors.affiliation: Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsuzaki
authors.affiliation: Faculty of Science, Gakushuin University, Mejiro 1-5-1, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Toyama
authors.affiliation: Faculty of Science, Gakushuin University, Mejiro 1-5-1, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohno
mesh_terms: D062406:Fukushima Nuclear Accident; D007455:Iodine / Q000032:analysis*; D007457:Iodine Radioisotopes / Q000032:analysis; D007564:Japan; D013058:Mass Spectrometry; D055848:Nuclear Power Plants; D011847:Radioactive Fallout / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013667:Technetium / Q000737:chemistry
chemical_list: D007457:Iodine Radioisotopes; D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive; D013667:Technetium; D007455:Iodine
keywords: (129)I; (131)I; Deposition density; Fukushima; Reconstruction; Soil