title: FWT and OBT concentrations in pine needle samples collected at Toki, Japan (1998-2012).
abstract: Free water tritium (FWT) and organically bound tritium (OBT) concentrations in pine needles have been investigated to understand the regional background tritium concentration in Toki City. Samples were regularly collected from pine trees on the National Institute for Fusion Science campus (1998-2012) and the nearby Shiomi Park (SP; 2002-12). FWT and OBT concentrations of the former samples ranged from 0.33 to 0.92 and 0.41 to 1.10 Bq l(-1), respectively, while those of the latter samples ranged from 0.32 to 0.86 and 0.33 to 0.79 Bq l(-1), respectively. Results of both sampling sites were almost the same, and they have been gradually decreased year by year. Concentration level of tritium for Toki City was close to the average background level in Japan. The OBT/FWT ratios were almost 1.0. The apparent half-life of FWT in this period was estimated as almost 10 y, and that of OBT was estimated as almost 12 y; these values were almost the same as the physical half-life.
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan akata.naofumi@lhd.nifs.ac.jp.
authors.forename: N
authors.initials: N
authors.lastname: Akata
authors.affiliation: Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Aomori, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kakiuchi
authors.affiliation: Kyushu Environmental Evaluation Association, 1-10-1 Matsukadai, Higashi-ku, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tamari
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kawano
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Miyake
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uda
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nishimura
mesh_terms: D001417:Background Radiation; D001681:Biological Assay / Q000379:methods; D007564:Japan; D009930:Organic Chemicals / Q000737:chemistry; D028223:Pinus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014316:Tritium / Q000032:analysis*; D014867:Water / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals; D014867:Water; D014316:Tritium