著者

坂本 文徳 大貫 敏彦 香西 直文 五十嵐 翔祐 山崎 信哉 吉田 善行 田中 俊一

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.1111290030, (Released:2011-11-30)

参考文献数

12

被引用文献数

8 10

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The environmental behavior of radioactive Cs in the fallout from the accident of the Fukushima Daiichi Nuclear Power Plant has been studied by measuring its spatial distribution on/in trees, plants, and surface soil beneath the plants using autoradiography analysis. The results of autoradiography analysis showed that radioactive Cs was distributed on the branches and leaves of trees that were present during the accident and that only a small fraction of radioactive Cs was transported to new branches and leaves grown after the accident. Radioactive Cs was present on the grass and rice stubble on the soils, but not in the soils beneath the grass and rice stubble, indicating that the radioactive Cs was deposited on the grass and the rice plant. In addition, the ratio of the radioactive Cs that penetrated into the soil layer by weathering was very small two months after the accident. These results indicate that trees and other plants are the reservoir of the fallout Cs and function to retard the fallout Cs migration with rain water.

著者

坂本 文徳 大貫 敏彦 香西 直文 五十嵐 翔祐 山崎 信哉 吉田 善行 田中 俊一

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.11, no.1, pp.1-7, 2012 (Released:2012-02-15)

参考文献数

12

被引用文献数

8 10

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The environmental behavior of radioactive Cs in the fallout from the accident of the Fukushima Daiichi Nuclear Power Plant has been studied by measuring its spatial distribution on/in trees, plants, and surface soil beneath the plants using autoradiography analysis. The results of autoradiography analysis showed that radioactive Cs was distributed on the branches and leaves of trees that were present during the accident and that only a small fraction of radioactive Cs was transported to new branches and leaves grown after the accident. Radioactive Cs was present on the grass and rice stubble on the soils, but not in the soils beneath the grass and rice stubble, indicating that the radioactive Cs was deposited on the grass and the rice plant. In addition, the ratio of the radioactive Cs that penetrated into the soil layer by weathering was very small two months after the accident. These results indicate that trees and other plants are the reservoir of the fallout Cs and function to retard the fallout Cs migration with rain water.

著者

宇都宮 聡 岩田 孟 川元 侑治 金子 誠 仲松 有紀 大貫 敏彦 難波 謙二

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2012年度日本地球化学会第59回年会講演要旨集

巻号頁・発行日

pp.37, 2012 (Released:2012-09-01)

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本研究では、環境中に放出された長崎型原子爆弾由来Puの化学状態、サイズ依存性を調べ、Puの環境中における化学種変化を分析した結果、約60 %のPuが有機物と結合した状態で、約30 %がPu酸化物様の難溶解性核種として存在することが示された。長崎西山地区表層環境下においてPu移行は起こりにくいことが分かり、環境中に存在する有機物がPu化学種に重大な影響を及ぼすことが示唆された。さらに、福島における土壌中Puの定量、分布を調査した福島第一原発から3 kmの地点におけるPuの放射能濃度と同位体放射能比は、238Pu=0.034~0.209 Bq/kg、239+240Pu=0,08~0.11 Bq /kg、238Pu / 239+240Pu=0.319~2.60であった。

著者

宇都宮 聡 大貫 敏彦

出版者

九州大学

雑誌

挑戦的萌芽研究

巻号頁・発行日

2016-04-01

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本研究では福島第一原発から放出された高濃度放射性セシウム含有微粒子(CsMP)の簡易定量法を福島県内の土壌に適用して、CsMPの個数と放射能寄与率(RF)を示しました。原発付近では個数が多く低RF値で、水溶性セシウムの寄与が大きくなりました。北西方向の汚染地帯にはCsMPと水溶性セシウムの寄与が高く、これは9つの主要なプルームのうちプルーム3と8の軌跡に相当します。一方で南西方向では放射能は低いですが、RF値は80%程度と高くなりました。これはプルーム2の軌跡に相当します。これからCsMPは14日~15日の短い期間に形成され放出されたこと、初期は3号機からCsMPが放出されたと推定されました。

著者

坂本 文徳 大貫 敏彦 香西 直文 山崎 信哉 吉田 善行 難波 謙二

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J13.002, (Released:2013-10-10)

参考文献数

20

被引用文献数

4 5

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The local area distribution and relocation of radioactive cesium deposited in trees after the 2011 tsunami-related accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) have been studied by measuring the spatial distribution of cesium on/in trees by autoradiography analysis. Samples of trees were collected from places located between 4 and 55 km from FDNPP approximately 2, 8, 20, and 22 months after the accident. The autoradiography analyses of Cryptomeria japonica, Torreya nucifera, and Thujopsis dolabrata var. hondae samples collected approximately 2 and 8 months after the accident showed that radioactive Cs was mainly distributed as spots on the branches and leaves of the trees emerged before the accident, and was detected in negligible amounts in new branch and leaves that emerged after the accident. On the contrary, radioactive Cs was detected at the outermost tip of the branches in the trees collected 20 months after the accident. Morus alba samples collected 22 months after the accident contained radioactive Cs inside and outside their stems, even though no radioactive Cs was detected in their roots, strongly suggesting that a certain amount of radioactive Cs was translocated from the outside to the inside of stems. These results indicate that the distribution of radioactive Cs deposited on/in the trees gradually changes with time (scale: year).

著者

古木 元気 井元 純平 落合 朝須美 山崎 信哉 難波 謙二 大貫 敏彦 Bernd Grambow Rodney C. Ewing 宇都宮 聡

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2016年度日本地球化学会第63回年会講演要旨集

巻号頁・発行日

pp.42, 2016 (Released:2016-11-09)

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現行の環境中放射性Cs移行モデルに対する新たな因子として高濃度放射性Cs含有微粒子(CsMPs)の動態を調べた。福島県熊川河口堆積物、河川流域表層土壌から福島原発由来CsMPsを単離後、原子スケールで分析した結果、内部構造は他のCsMPsと同様にFe-Zn酸化物ナノ粒子の凝集体がSiO2のマトリックスに覆われていた。また、粒子内部からCsClおよびCsOHの内包物が同定された。河川流域と河口堆積物で同様の粒子が検出されたことから、CsMPsが表層水中を移行したことが示され、その後の海洋への流出が示唆された。

著者

坂本 文徳 大貫 敏彦 香西 直文 山崎 信哉 吉田 善行 難波 謙二

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.12, no.4, pp.257-266, 2013

被引用文献数

5

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The local area distribution and relocation of radioactive cesium deposited in trees after the 2011 tsunami-related accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) have been studied by measuring the spatial distribution of cesium on/in trees by autoradiography analysis. Samples of trees were collected from places located between 4 and 55 km from FDNPP approximately 2, 8, 20, and 22 months after the accident. The autoradiography analyses of <i>Cryptomeria japonica</i>, <i>Torreya nucifera</i>, and <i>Thujopsis dolabrata</i> var. <i>hondae</i> samples collected approximately 2 and 8 months after the accident showed that radioactive Cs was mainly distributed as spots on the branches and leaves of the trees emerged before the accident, and was detected in negligible amounts in new branch and leaves that emerged after the accident. On the contrary, radioactive Cs was detected at the outermost tip of the branches in the trees collected 20 months after the accident. <i>Morus alba</i> samples collected 22 months after the accident contained radioactive Cs inside and outside their stems, even though no radioactive Cs was detected in their roots, strongly suggesting that a certain amount of radioactive Cs was translocated from the outside to the inside of stems. These results indicate that the distribution of radioactive Cs deposited on/in the trees gradually changes with time (scale: year).<br>

著者

坂本 文徳 大貫 敏彦 香西 直文 山崎 信哉 吉田 善行 難波 謙二

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.12, no.4, pp.257-266, 2013 (Released:2013-11-15)

参考文献数

20

被引用文献数

4 5

---

The local area distribution and relocation of radioactive cesium deposited in trees after the 2011 tsunami-related accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) have been studied by measuring the spatial distribution of cesium on/in trees by autoradiography analysis. Samples of trees were collected from places located between 4 and 55 km from FDNPP approximately 2, 8, 20, and 22 months after the accident. The autoradiography analyses of Cryptomeria japonica, Torreya nucifera, and Thujopsis dolabrata var. hondae samples collected approximately 2 and 8 months after the accident showed that radioactive Cs was mainly distributed as spots on the branches and leaves of the trees emerged before the accident, and was detected in negligible amounts in new branch and leaves that emerged after the accident. On the contrary, radioactive Cs was detected at the outermost tip of the branches in the trees collected 20 months after the accident. Morus alba samples collected 22 months after the accident contained radioactive Cs inside and outside their stems, even though no radioactive Cs was detected in their roots, strongly suggesting that a certain amount of radioactive Cs was translocated from the outside to the inside of stems. These results indicate that the distribution of radioactive Cs deposited on/in the trees gradually changes with time (scale: year).