@article{oai:hirosaki.repo.nii.ac.jp:00005445,
 author = {Yang, Guosheng and Tazoe, Hirofumi and Hayano, Kazuhiko and Okayama, Kumiko and Yamada, Masatoshi},
 journal = {SCIENTIFIC REPORTS},
 month = {Oct},
 note = {Six years after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, data for U-236 and U-236/U-238 have remained limited to a few heavily contaminated samples. In the present study, activities of U-236, Pu-239, and Pu-240, along with other U isotopes in 46 soil samples both heavily and lightly contaminated by this accident were measured by inductively coupled plasma-mass spectrometry (ICP-MS) and triple-quadrupole ICP-MS. The U-236 activities and U-236/U-238 atom ratios in these soil samples were in the range of (0.469-24.4) x 10(-5) Bq kg(-1) and ((0.099-1.35) x 10(-7)), respectively. Higher Pu-240/Pu-239 atom ratios (0.245-0.312) and Pu-238/Pu239+240 activity ratios (0.859-1.62) indicated Pu contamination originated from this accident and global fallout in some samples. For those soil samples along with black substances collected along roads in Fukushima Prefecture, high linear correlations were presented between U-236 activities and Pu239+240 activities (Pearson's r = 0.755, p < 0.01), and between U-236 activities and Pu-238 activities (Pearson's r = 0.844, p < 0.01). The analysis of these soil samples confirmed the release of U-236, although in trace amounts, during the FDNPP accident.},
 title = {Isotopic compositions of U-236, Pu-239, and Pu-240 in soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident},
 volume = {7},
 year = {2017}
}