Feasibility of using U-236 to reconstruct close-in fallout deposition from the Hiroshima atomic bomb

Author(s)

Aya Sakaguchi, K. Kawai, Peter Steier, T. Imanaka, Masaharu Hoshi, Satoru Endo, Kassym Zhumadilov, Masayoshi Yamamoto

Abstract

The first results on the feasibility of using U-236 to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout Cs-137 and Pu239 + 240. The results for global fallout U-236 in soil samples (0-30 cm) from Ishikawa prefecture showed that the deposition density of U-236 from the global fallout can be accurately evaluated using AMS. All deposited U-236, Cs-137 and Pu239 + 240 appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for U-236/Pu239 + 240 and U-236/Cs-137 ratios that the downward behavior of U-236 in the soil was apparently similar to that of Pu239 + 240, while the Cs-137 was liable to be retained in upper layers compared with U-236 and Pu239 + 240. The accumulated levels were 1.78 x 10(13) atoms m(-2) for U-236, 4340 Bq m(-2) for Cs-137 and tin Bq m(-2) for Pu239 + 240. The ratios of U-236/Cs-137 and U-236/Pu239 + 240 were (4.10 +/- 0.12) x 10(9) and (1.26 +/- 0.04) x 10(11) atoms Bq(-1), respectively. Results of U-236, (CS)-C-137 and Pu239 + 240 measurements for the seven soil cores (0-30 cm) from Hiroshima were discussed on the basis of ratios of U-236/(CS)-C-137 and U-236/Pu239 + 240 by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of U-236 accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout U-236 produced by the Hiroshima A-bomb seems difficult to observe.

Organisation(s)

Isotope Physics

External organisation(s)

Hiroshima University, Kanazawa University, Kyoto University

Journal

Science of the Total Environment

Volume

408

Pages

5392-5398

No. of pages

7

ISSN

0048-9697

DOI

https://doi.org/10.1016/j.scitotenv.2010.07.073

Publication date

2010

Peer reviewed

Yes

Austrian Fields of Science 2012

103014 Nuclear physics

Portal url

https://ucrisportal.univie.ac.at/en/publications/4da56c72-c211-4ed6-aad9-d1df254268ea