title: Deposition in Chiba prefecture, Japan, of Fukushima Daiichi Nuclear Power Plant fallout.
abstract: Radioactivity from the Fukushima Daiichi Nuclear Power Plant (F-1NPP) accident in deposition samples has been monitored at the National Institute of Radiological Sciences (NIRS) in Chiba Prefecture, Japan, located about 220 km south-southwest of the F-1NPP. Sampling was carried out from 15 March 2011, two to three times a day for 10 d and then once a day until 22 April 2011. Gamma-ray spectrometry of fallout deposition samples revealed the presence of (131)I, (132)I, (132)Te, (134)Cs, and (137)Cs. The largest deposition was observed during 7:00-16:00 on 21 March. The estimated total deposition densities at NIRS were 1.40 × 10(5) Bq m(-2) for (131)I, 4.12 × 10(4) Bq m(-2) for (132)Te, 1.45 × 10(4) Bq m(-2) for (134)Cs, and 1.48 × 10(4) Bq m(-2) for (137)Cs (corrected to 11 March 2011). The obtained densities of (134)Cs and (137)Cs were also supported by the accumulated amount of (134)Cs and (137)Cs in soil near the deposition sampling site. For the vertical profile of those radionuclides in soil at NIRS, about 94% of the total deposition was distributed in the top 10 mm depth on 26 April 2011.
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555, Japan. nobu@nirs.go.jp
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Ishii
authors.forename: Keiko
authors.initials: K
authors.lastname: Tagami
authors.forename: Hyoe
authors.initials: H
authors.lastname: Takata
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fujita
authors.forename: Isao
authors.initials: I
authors.lastname: Kawaguchi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Shigeo
authors.initials: S
authors.lastname: Uchida
mesh_terms: D000047:Academies and Institutes; D002588:Cesium Radioisotopes / Q000032:analysis; D062406:Fukushima Nuclear Accident; D007564:Japan; D055848:Nuclear Power Plants; D011847:Radioactive Fallout / Q000032:analysis*; D012987:Soil / Q000737:chemistry
chemical_list: D002588:Cesium Radioisotopes; D011847:Radioactive Fallout; D012987:Soil