title: Spatial distributions of radionuclides deposited onto ground soil around the Fukushima Dai-ichi Nuclear Power Plant and their temporal change until December 2012.
abstract: Spatial distributions and temporal changes of radioactive fallout released by the Fukushima Dai-ichi Nuclear Power Plant accident have been investigated by two campaigns with three measurement schedules. The inventories (activities per unit area) of the radionuclides deposited onto ground soil were measured using portable gamma-ray spectrometers at nearly 1000 locations (at most) per measurement campaign. Distribution maps of the inventories of (134)Cs, (137)Cs, and (110m)Ag as of March, September, and December 2012 were constructed. No apparent temporal change of the radionuclide inventories was observed from March to December 2012. Weathering effects (e.g., horizontal mobility) were not noticeable during this period. Spatial dependence in the ratios of (134)Cs/(137)Cs and (110m)Ag/(137)Cs were observed in the Tohoku and Kanto regions. The detailed maps of (134)Cs and (137)Cs as of September 2012 and December 2012 were constructed using the relationship between the air dose rate and the inventory.
authors.affiliation: Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 2-2-2, Uchisaiwai-cho, Chiyoda, Tokyo, 100-8577, Japan. Electronic address: mikami.satoshi@jaea.go.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mikami
authors.affiliation: General Analysis Division, Japan Chemical Analysis Center, 295-3, Sanno-cho, Inage, Chiba, Chiba, 263-0002, Japan. Electronic address: t-maeyama@jcac.or.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Maeyama
authors.affiliation: Division of Emergency Preparedness Technology, Nuclear Safety Technology Center, 5-1-3-101, Hakusan, Bunkyo, Tokyo, 112-8604, Japan. Electronic address: yoshi-hoshide@nustec.or.jp.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Hoshide
authors.affiliation: Institute of Radiation Measurements, 2-4 Shirane, Shirakata, Tokai-mura, Naka, Ibaraki, 319-1106, Japan. Electronic address: r.sakamoto@irm.or.jp.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sakamoto
authors.affiliation: Radioactive Analysis Division, Japan Chemical Analysis Center, 295-3, Sanno-cho, Inage, Chiba, Chiba, 263-0002, Japan. Electronic address: s-sato@jcac.or.jp.
authors.forename: Shoji
authors.initials: S
authors.lastname: Sato
authors.affiliation: Division of Emergency Preparedness Technology, Nuclear Safety Technology Center, 5-1-3-101, Hakusan, Bunkyo, Tokyo, 112-8604, Japan. Electronic address: okuda@nustec.or.jp.
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Okuda
authors.affiliation: Emergency Response, Radiation Protection Division, Institute of Radioprotection and Nuclear Safety, BP 17, Fontenay-aux-Roses, 92262, France. Electronic address: stephanie.demongeot@irsn.fr.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Demongeot
authors.affiliation: Environment, Radiation Protection Division, Institute of Radioprotection and Nuclear Safety, Bat 501, Bois des Rames, Orsay, 91400, France. Electronic address: rodolfo.gurriaran@irsn.fr.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Gurriaran
authors.affiliation: Safety Management Group, Nishina Center for Accelerator-Based Science, RIKEN, 2-1, Hirosawa, Wako, Saitama, 351-0198, Japan. Electronic address: uwamino@riken.jp.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Uwamino
authors.affiliation: Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan. Electronic address: hiros980@ies.life.tsukuba.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Research Center for Nuclear Physics, Osaka University, 10-1, Mihogaoka, Ibaraki, Osaka, 567-0047, Japan. Electronic address: fujiwara@rcnp.osaka-u.ac.jp.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Fujiwara
authors.affiliation: Hitachi Solutions East Japan, Ltd., NBF Sendai Honcho Bldg, 2-16-10 Honcho, Aoba-ku, Sendai, 980-0014, Japan. Electronic address: tetsuro.sato.aj@hitachi-solutions.com.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sato
authors.affiliation: Center for Computational Science & e-Systems, Japan Atomic Energy Agency, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8587, Japan. Electronic address: takemiya.hiroshi@jaea.go.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takemiya
authors.affiliation: Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency, 2-2-2, Uchisaiwai-cho, Chiyoda, Tokyo, 100-8577, Japan. Electronic address: kimiaki.saito@jaea.go.jp.
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Saito
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis; D062406:Fukushima Nuclear Accident; D062305:Geographic Mapping; D007564:Japan; D055848:Nuclear Power Plants; D011834:Radiation Monitoring; D011847:Radioactive Fallout / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*; D012621:Seasons; D012834:Silver / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013051:Spectrometry, Gamma
chemical_list: D002588:Cesium Radioisotopes; D011847:Radioactive Fallout; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive; D012834:Silver
keywords: Distribution; Fukushima; In situ measurement; Inventory; Portable gamma-ray spectrometer; Temporal change