title: Detection and activity of iodine-131 in brown algae collected in the Japanese coastal areas.
abstract: Iodine-131 (physical half-life: 8.04 days) was detected in brown algae collected off the Japanese coast. Brown algae have been extensively used as bioindicators for radioiodine because of their ability to accumulate radionuclides in high concentration factors. The maximum measured specific activity of (131)I in brown algae was 0.37 + or - 0.010 Bq/kg-wet. Cesium-137 was also detected in all brown algal samples used in this study. There was no correlation between specific activities of (131)I and (137)Cs in these seaweeds. The specific activity of (137)Cs ranged from 0.0034 + or - 0.00075 to 0.090 + or - 0.014 Bq/kg-wet. Low specific activity and minimal variability of (137)Cs in brown algae indicated that past nuclear weapon tests were the source of (137)Cs. Although nuclear power stations and nuclear fuel reprocessing plants are known to be pollution sources of (131)I, there was no relationship between the sites where (131)I was detected and the locations of nuclear power facilities. Most of the sites where (131)I was detected were near big cities with large populations. Iodine-131 is frequently used in diagnostic and therapeutic nuclear medicine. On the basis of the results, we suggest that the likely pollution source of (131)I, detected in brown seaweeds, is not nuclear power facilities, but nuclear medicine procedures.
authors.affiliation: Fisheries Research Agency, 15F Queen's Tower B, Minato Mirai Nishi-ku, Yokohama, Kanagawa 220-6115, Japan. takam@affrc.go.jp
authors.forename: Takami
authors.initials: T
authors.lastname: Morita
authors.forename: Kentaro
authors.initials: K
authors.lastname: Niwa
authors.forename: Ken
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kasai
authors.forename: Haruya
authors.initials: H
authors.lastname: Yamada
authors.forename: Kou
authors.initials: K
authors.lastname: Nishiutch
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Waichiro
authors.initials: W
authors.lastname: Godo
authors.forename: Seiya
authors.initials: S
authors.lastname: Taino
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Koji
authors.initials: K
authors.lastname: Takeno
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Nishigaki
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Hisamichi
authors.initials: H
authors.lastname: Aratake
authors.forename: Shingo
authors.initials: S
authors.lastname: Kamonoshita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Takuya
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Sigeyoshi
authors.initials: S
authors.lastname: Otosaka
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Imanaka
mesh_terms: D007457:Iodine Radioisotopes / Q000032:analysis*; D007564:Japan; D000459:Phaeophyceae / Q000737:chemistry*
chemical_list: D007457:Iodine Radioisotopes