title: Atmospheric fallout of (129)I in Japan before the Fukushima accident: regional and global contributions (1963-2005).
abstract: Atmospheric (129)I deposition was studied in different locations of Japan (Akita, Tsukuba, Tokyo, and Ishigaki Island) with samples collected between 1963 and 2005 in order to understand the distribution and sources of this nuclide and provide a reference deposition level prior to the Fukushima accident. Over this time period, the deposition pattern of (129)I in Tsukuba and Tokyo (on the Pacific side) differed from that of Akita (on the Japan Sea side). The primary source of deposition in Tsukuba and Tokyo is related to the (129)I discharge from domestic reprocessing in Tokai-mura. In contrast, the time-series pattern of deposition in Akita seems to have been influenced by (129)I discharges from reprocessing facilities in Europe and the transport of this radionuclide by westerly winds to coastlines of the Japan Sea. The (129)I deposition in Ishigaki (one of the southernmost islands in Japan) is influenced primarily by oceanic air masses (easterly winds), and deposition was 1 order of magnitude lower than that observed in Tsukuba and Tokyo. Cumulative (129)I deposition in Tokyo before the Fukushima accident was estimated at 13 mBq/m(2). The results of this study on deposition contribute to understanding the deposition levels of (129)I prior to the accident.
authors.affiliation: Department of Chemistry, Gakushuin University , 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Toyama
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Muramatsu
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Michio
authors.initials: M
authors.lastname: Aoyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsuzaki
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007457:Iodine Radioisotopes / Q000032:analysis*; D007564:Japan; D013058:Mass Spectrometry
chemical_list: D000396:Air Pollutants, Radioactive; D007457:Iodine Radioisotopes