title: Variability of radiocaesium inventory in Fukushima soil cores from one site measured at different times.
abstract: The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has resulted in the deposition of radioactive contamination of soils mainly by (134)Cs and (137)Cs. The contaminated areas are of a great concern since external radiation may lead to significant long-term doses to humans and animals. External dose rate above ground will decrease with physical decay of the radionuclides and as they migrate deeper into the soil with time. In the present study, depth profiles of Cs radioisotopes have been studied at different times over a period of 1 y. Radiocaesium inventories for (134)Cs and (137)Cs down to a depth of 10 cm at the four measurement times varied from 2.09 to 4.14 MBq m(-2) with coefficient of variation (CV): 27.4 %, n = 4 and from 2.13 to 4.23 MBq m(-2) with CV: 27.3 %, n = 4, respectively. The activity ratio for (134)Cs/(137)Cs decreased from 0.62 to 0.46 during 1 y of measurement i.e. July 2012 to June 2013. However, the ratio with decay correction (15 March 2011) was found to be constant ∼1, indicating contamination from FDNPP origin. In order to understand the radiocaesium distribution in soil profile, physico-chemical characterisation of soil has been carried out.
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan Bhabha Atomic Research Centre, Trombay, Mumbai, India.
authors.forename: S
authors.initials: S
authors.lastname: Mishra
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan sahoo@nirs.go.jp.
authors.forename: S K
authors.initials: SK
authors.lastname: Sahoo
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Arae
authors.affiliation: Fukushima Medical University, Hikarigaoka 1, Fukushima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Sorimachi
authors.affiliation: Hirosaki University, Graduate School of Health Sciences, Aomori, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hosoda
authors.affiliation: Hirosaki University, Graduate School of Health Sciences, Aomori, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tokonami
authors.affiliation: Fukushima Medical University, Hikarigaoka 1, Fukushima, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D011834:Radiation Monitoring / Q000379:methods*; D011847:Radioactive Fallout / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013997:Time Factors
chemical_list: D002588:Cesium Radioisotopes; D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive