title: Plutonium concentration and isotopic ratio in soil samples from central-eastern Japan collected around the 1970s.
abstract: Obtaining Pu background data in the environment is essential for contamination source identification and assessment of environmental impact of Pu released from the Fukushima Daiichi nuclear power plant (FDNPP) accident. However, no baseline information on Pu isotopes in Fukushima Prefecture has been reported. Here we analyzed 80 surface soil samples collected from the central-eastern Japan during 1969-1977 for (239+240)Pu activity concentration and (240)Pu/(239)Pu atom ratio to establish the baseline before the FDNPP accident. We found that (239+240)Pu activity concentrations ranged from 0.004 -1.46 mBq g(-1), and (240)Pu/(239)Pu atom ratios varied narrowly from 0.148 to 0.229 with a mean of 0.186 ± 0.015. We also reconstructed the surface deposition density of (241)Pu using the (241)Pu/(239)Pu atom ratio in the Japanese fallout reference material. The obtained results indicated that, for the FDNPP-accident released (241)Pu, a similar radiation impact can be estimated as was seen for the global fallout deposited (241)Pu in the last decades.
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
authors.forename: Guosheng
authors.initials: G
authors.lastname: Yang
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tagami
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Uchida
mesh_terms: D062406:Fukushima Nuclear Accident; D007564:Japan; D013058:Mass Spectrometry; D008970:Molecular Weight; D011005:Plutonium / Q000032:analysis*; D012987:Soil / Q000737:chemistry
chemical_list: D012987:Soil; D011005:Plutonium