Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Kimiaki Saito; Isao Tanihata; Mamoru Fujiwara; Takashi Saito; Susumu Shimoura; Takaharu Otsuka; Yuichi Onda; Masaharu Hoshi; Yoshihiro Ikeuchi; Fumiaki Takahashi; Nobuyuki Kinouchi; Jun Saegusa; Akiyuki Seki; Hiroshi Takemiya; Tokushi Shibata

doi:10.1016/j.jenvrad.2014.02.014

Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

J Environ Radioact. 2015 Jan:139:308-319. doi: 10.1016/j.jenvrad.2014.02.014. Epub 2014 Apr 2.

Authors

Affiliations

¹ Japan Atomic Energy Agency, 2-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo 100-8577, Japan. Electronic address: saito.kimiaki@jaea.go.jp.
² Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
³ Japan Atomic Energy Agency, 2-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo 100-8577, Japan.
⁴ University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
⁵ University of Tsukuba, 1-1-1 A-405 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
⁶ Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
⁷ Japan Chemical Analysis Center, 295-3 Sannocho, Inage-ku, Chiba-shi 263-0002, Japan.
⁸ Japan Radioisotope Association, 2-28-45 Honkomagome, Bunkyo, Tokyo 113-8941, Japan.

PMID: 24703526
DOI: 10.1016/j.jenvrad.2014.02.014

Abstract

Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides.

Keywords: Deposition density maps; Fukushima Dai-ichi NPP accident; Gamma-ray emitting radioactive nuclides; Gamma-ray spectrometry; Soil sampling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Fukushima Nuclear Accident*
Geographic Mapping
Japan
Nuclear Power Plants
Radiation Monitoring*
Radioactive Fallout / analysis*
Radioisotopes / analysis*
Soil Pollutants, Radioactive / analysis*

Substances

Radioactive Fallout
Radioisotopes
Soil Pollutants, Radioactive