title: Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan.
abstract: Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments.
authors.affiliation: Nakaminato Laboratory for Marine Radioecology, National Institute of Radiological Sciences, Isozaki-cho, Hitachinaka, Ibaraki, Japan. nakanishi.takahiro@jaea.go.jp
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Aono
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamada
authors.forename: Masashi
authors.initials: M
authors.lastname: Kusakabe
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D007564:Japan; D013058:Mass Spectrometry / Q000379:methods*; D011834:Radiation Monitoring; D012623:Seawater / Q000032:analysis; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013667:Technetium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D014875:Water Pollutants, Radioactive; D013667:Technetium