著者

Ryugo S. HAYANO Masaharu TSUBOKURA Makoto MIYAZAKI Akihiko OZAKI Yuki SHIMADA Toshiyuki KAMBE Tsuyoshi NEMOTO Tomoyoshi OIKAWA Yukio KANAZAWA Masahiko NIHEI Yu SAKUMA Hiroaki SHIMMURA Junichi AKIYAMA Michio TOKIWA

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.91, no.8, pp.440-446, 2015-10-09 (Released:2015-10-09)

参考文献数

14

被引用文献数

18 28

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BABYSCAN, a whole-body counter (WBC) for small children was developed in 2013, and units have been installed at three hospitals in Fukushima Prefecture. Between December, 2013 and March, 2015, 2707 children between the ages of 0 and 11 have been scanned, and none had detectable levels of radioactive cesium. The minimum detectable activities (MDAs) for 137Cs were ≤3.5 Bq kg−1 for ages 0–1, decreasing to ≤2 Bq kg−1 for ages 10–11. Including the 134Cs contribution, these translate to a maximum committed effective dose of ∼16 µSv y−1 even for newborn babies, and therefore the internal exposure risks can be considered negligibly small.Analysis of the questionnaire filled out by the parents of the scanned children regarding their families’ food and water consumption revealed that the majority of children residing in the town of Miharu regularly consume local or home-grown rice and vegetables, while in Minamisoma, a majority avoid tap water and produce from Fukushima. The data show, however, no correlation between consumption of locally produced food and water and the children’s body burdens.

著者

Ryugo S. HAYANO Masaharu TSUBOKURA Makoto MIYAZAKI Hideo SATOU Katsumi SATO Shin MASAKI Yu SAKUMA

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.89, no.4, pp.157-163, 2013-04-11 (Released:2013-04-11)

参考文献数

14

被引用文献数

85 102

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The Fukushima Dai-ichi NPP accident contaminated the soil of densely-populated regions in Fukushima Prefecture with radioactive cesium, which poses significant risks of internal and external exposure to the residents. If we apply the knowledge of post-Chernobyl accident studies, internal exposures in excess of a few mSv/y would be expected to be frequent in Fukushima.Extensive whole-body-counter surveys (n = 32,811) carried out at the Hirata Central Hospital between October, 2011 and November, 2012, however show that the internal exposure levels of residents are much lower than estimated. In particular, the first sampling-bias-free assessment of the internal exposure of children in the town of Miharu, Fukushima, shows that the 137Cs body burdens of all children (n = 1,383, ages 6–15, covering 95% of children enrolled in town-operated schools) were below the detection limit of 300 Bq/body in the fall of 2012. These results are not conclusive for the prefecture as a whole, but are consistent with results obtained from other municipalities in the prefecture, and with prefectural data.(Communicated by Toshimitsu YAMAZAKI, M.J.A.)

著者

Ryugo S. HAYANO Masaharu TSUBOKURA Makoto MIYAZAKI Hideo SATOU Katsumi SATO Shin MASAKI Yu SAKUMA

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.91, no.3, pp.92-98, 2015-03-11 (Released:2015-03-11)

参考文献数

17

被引用文献数

4 7

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Comprehensive whole-body counter surveys of Miharu-town school children have been conducted for four consecutive years, in 2011–2014. This represents the only long-term sampling-bias-free study of its type conducted after the Fukushima Dai-ichi accident. For the first time in 2014, a new device called the Babyscan, which has a low 134/137Cs MDA of <50 Bq/body, was used to screen the children shorter than 130 cm. No child in this group was found to have detectable level of radiocesium. Using the MDAs, upper limits of daily intake of radiocesium were estimated for each child. For those screened with the Babyscan, the upper intake limits were found to be ≲1 Bq/day for 137Cs. Analysis of a questionnaire filled out by the children’s parents regarding their food and water consumption shows that the majority of Miharu children regularly consume local and/or home-grown rice and vegetables. This however does not increase the body burden.

著者

Ryugo S. HAYANO Masaharu TSUBOKURA Makoto MIYAZAKI Hideo SATOU Katsumi SATO Shin MASAKI Yu SAKUMA

出版者

日本学士院

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.90, no.6, pp.211-213, 2014-06-11 (Released:2014-06-11)

参考文献数

9

被引用文献数

3 5

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Comprehensive whole-body counter surveys covering over 93% of the school children between the ages of 6 and 15 in Miharu town, Fukushima Prefecture, have been conducted for three consecutive years, in 2011, 2012 and 2013. Although the results of a questionnaire indicate that approximately 60% of the children have been regularly eating local or home-grown rice, in 2012 and 2013 no child was found to exceed the 137Cs detection limit of 300 Bq/body.

著者

Ryugo S. HAYANO Ryutaro ADACHI

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.89, no.5, pp.196-199, 2013-05-10 (Released:2013-05-10)

参考文献数

8

被引用文献数

12 27

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The first objective data showing the geographical locations of people in Fukushima after the Fukushima Dai-ichi nuclear power plant accident, obtained by an analysis of GPS (Global Positioning System)-enabled mobile phone logs, are presented. The method of estimation is explained, and the flow of people into and out of the 20 km evacuation zone during the accident is visualized.(Communicated by Toshimitsu YAMAZAKI, M.J.A.)