Preface

はじめに
多くの皆様のご支援とご協力により、第6回福島大学環境放射能研究所成果報告会の開催を迎えることができました。また、今回、「放射能環境動態・影響評価ネットワーク共同研究拠点」の報告会を、平衡して実施できたことを大変嬉しく思います。 2011年の事故から9年が経過し、いよいよ来年は10年を迎えます。東電福島第一原発が立地する大熊町では、2018年から大川原地区の試験水田で営農促進に向け大熊町、福島県、農研機構、福島大学による調査研究が行われています。2019年に避難指示区域の一部が解除され、イネの放射性セシウム濃度は基準値を充分に下回ることが確認され、2020年1月13日には試験水田で収穫されたもち米で餅つき大会が行われました。2011年の事故以降、研究環境を大きく変え、被災地に寄り添う研究に従事する研究者も数多くいますが、地元住民と研究者が一致協力し、復興を適進し、地元に明るい話題がもたらされたことは大変喜ばしいことと思います。成果報告会では、福島のみならず、様々な環境放射生態学に関する最新研究成果を交換し、今後の研究発展に実り多い場となることを願っています。昨年から、専門家による口頭発表・ボスター発表と、一般を対象とした分かりやすい発表分けて実施し、暫くは続けて行きたいと思っています。 2019年4月には、福島大学共生システム理工学研究科環境放射能学専攻に8名の修士学生を迎え、本報告会での発表も行われました。今後とも、福島大学として研究と教育の両面において一層活動を広げていきたいと思いますので、ご支援の程よろしくお願い申し上げます。
福島大学環境放射能研究所長
塚田　祥文
Hirofumi Tsukada
Director, Institute of Environmental Radioactivity, Fukushima University 1 2
Working Group for
Fukushima University IER Annual Symposium
成果報告会ワーキンググループ

Layout of the  3th,4th and 5th Floor,CORASSE FUKUSHIMAコラッセふくしま3・4・5階案内図(Associate Professor) (Associate Professor) (Project Assistant Professor) (Coordinator for International Affairs) (Research Coordinator) (Research Coordinator) Institute of Environmental Radioactivity, Fukushima University 1 Kanayagawa, Fukushima City, Fukushima 960-1296, JAPAN Phone +81-24-504-2114 Fax +81-24-503-2921 E-mail ier@adb.fukushima-u.ac.jp http://www.ier.fukushima-u.ac.jp/index_e.html福島大学環境放射能研究所〒 960-1296福島県福島市金谷川1番地電話024-504-2114  Fax  024-503-2921 E-mail ier@adb.fukushima-u.ac.jp http://www.ier.fukushima-u.ac.jp/index.html Venue : 1-20Mikawaminamimachi,Fukushima City,Fukushima Prefecture CORASSE FUKUSHIMA  Exhibition Area,3rd Floor Multipurpose Hall,4th Floor Lecture Room AB,Small,5th Floor会場：福島県福島市三河南町1番20号コラッセふくしま３階企画展示室4階多目的ホール5階研修室 AB、小研修室教授33
プログラム一日目
DAY 1
口頭発表
計測・分析分野
Oral
生態系分野
Ecosystems
-休憩-
- Break -
水環境分野
Aquatic Environment
阿武隈川の高水敷における137Csの蓄積と再移動

Opening Remarks Hirofumi Tsukada , Director , IER Impact of competing ions in aqueous matrix towards strontium selectivity in the designated solid-phase extraction systems: A comparative evaluation Ismail M.M. Rahman, M. Ferdous Alam, Yoshiaki Furusho, Kenji Nanba .............................................. 25 Impact of competing ions in aqueous matrix towards strontium selectivity in the designated solid-phase extraction systems: A comparative evaluation Ismail M.M. Rahman, M. Ferdous Alam, Yoshiaki Furusho, Kenji Nanba ......................................  25 Application of thermal ionization mass spectrometry for 90Sr analysis Application of thermal ionization mass spectrometry for 90Sr analysis Norbert Kavasi, Sarata Kumar Sahoo, Tatsuo Aono . Norbert Kavasi, Sarata Kumar Sahoo, Tatsuo Aono............................................................................................  26 Sorption-desorption behavior of Cs, Sr and U in Fukushima undisturbed soils after FDNPS Sorption-desorption behavior of Cs, Sr and U in Fukushima undisturbed soils after FDNPS accident Sharayu Kasar, Sarata Kumar Sahoo, Tatsuo Aono. . Radiation dose rate of Japanese cedar and plants collected from Okuma applying ERICA tool Nguyen Phuong Thoa, Shishido Koya, Hajime Ohira, Shingo Kaneko, Hirofumi Tsukada ...........  28 Concentrations of radiocesium in truffle-like fungi and their potential importance in forest ecosystems Radiation dose rate of Japanese cedar and plants collected from Okuma applying ERICA tool Nguyen Phuong Thoa, Shishido Koya, Hajime Ohira, Shingo Kaneko, Hirofumi Tsukada ............ 28地下生菌（トリュフ類）と小動物を介した森林内の放射性セシウムの動態把握保坂健太郎、山本航平、糟谷大河、南京沃、石庭寛子渓畔林から渓流生態系へのセシウム137の移行Kentaro Hosaka, Kohei Yamamoto, Taiga Kasuya, Kyung-Ok Nam, Hiroko Ishiniwa ..................... 29 Transfer of cesium 137 from riparian forest to a headwater stream ecosystem in Fukushima Tsutomu Kanasashi, Yoshiko Ayabe, Chisato Takenaka, Naoki Hijii . Establishment of a simplified approach to detect oxidative stress using 8-OHdG positive testicular cell measurements in the Large Japanese Field Mice Masanori Tamaoki, Manabu Onuma, Hiroko Ishiniwa .金指努、綾部慈子、竹中千里、肘井直樹アカネズミ精巣における8-OHdG陽性細胞の簡易測定法玉置雅紀、大沼学、石庭寛子…大気エアロゾルと植物・菌類間での放射性セシウム移行可能性の研究Possibility of transition of radio-cesium between aerosol and vegetation Kita Kazuyuki, Kanoh Mizuki, Niiya Watamu, Kimura Mao, Furukawa Jun, Hatano Yuko, Igarashi Yasuhito . Accumulation and redistribution of 137Cs on floodplains along the Abukuma River Yoshifumi Wakiyama, Alexei Konoplev, Valentin Golosov, Maxim Ivanov, Mikhail Komissarov...... 33 Ecological half-life of radiocesium in surficial bottom sediments of ponds in Fukushima based on in-situ measurements with plastic scintillation fibers脇山義史、Alexei Konoplev、Valentin Golosov、Maxim Ivanov、Mikhail Komissarov .................... 33 Ecological half-life of radiocesium in surficial bottom sediments of ponds in Fukushima based on in-situ measurements with plastic scintillation fibers Estiner W. Katengeza, Yukihisa Sanada, Kazuya Yoshimura, Kotaro Ochi, Takeshi Iimoto  ............ 34 Determination of labile 137Cs fraction in zooplankton associated with model analysis of bioavailable cesium transfer in marine food chain Estiner W. Katengeza, Yukihisa Sanada, Kazuya Yoshimura, Kotaro Ochi, Takeshi Iimoto ............ 34海洋動物プランクトン中易分解性137Cs画分の定量と生物移行モデルによる食物連鎖可給態奇与の解明立田穣、西川淳、青野辰雄、山崎慎之介、青山道夫、浜島第典、津旨大輔、小林卓也、石丸隆、神田發太、伊藤友加里、喜多村稔… Modeling of radionuclide transport in water systems and atmosphere: recent implementations for Fukushima and Chernobyl regions Yutaka Tateda, Jun Nishikawa, Tatsuo Aono, Shinnosuke Yamazaki, Michio Aoyama, Yasunori Hamajima, Daisuke Tsumune, Takuya Kobayashi,Takashi Ishimaru, Jota Kanda, Yukari Ito, Minoru Kitamura . Modeling of radionuclide transport in water systems and atmosphere: recent implementations for Fukushima and Chernobyl regions東京電力福島第一原発事故に由来する137Csの物質収支と大気、陸地、海洋間の移動の長期挙動育山道夫Closing Remarks Alexei Konoplev , Professor ,  IER 13:00開会挨拶環境放射能研究所所長:塚田祥文13:00 13:05  O-1 13:05   O-1 13:20   O-2 13:35   O-3 Sharayu Kasar, Sarata Kumar Sahoo,Tatsuo Aono ..............................................................................................................  27 13:50   O-4 14:05  O-5 14:20   O-6 14:35   O-7 14:50   O-8北和之、加納瑞季、二井矢航、木村茉央、古川純、羽田野祐子、五十嵐庚人…………………………………… 32 15:05 15:05 15:15   O-9 15:30   O-10 15:45  O-11 16:00  O-12 Mark Zheleznyak . Mark Zheleznyak . 16:15  O-13 16:30質疑心答16:55閉会挨拶環境放射能研究所教授:アレクセイコノブリョフ16:30 Q & A 16:55 5
プログラム二日目

ポスター発表(3F企画展示室、5F研修室AB、小研修室） Poster Session   (3F , 5F) -休　憩- 12:00 - Break -シンポジウム福島大学副学長:伊藤宏Opening Remarks開会疾拶環境放射能研究所所長:塚田祥文概要説明チェルノプイリと福島との環境放射能分野の共同研究難波謙二（福島大学）、 SATREPS課題「チェルノプイリ災害後の環境管理支援技術の確立」参加メンバー ………………………177 13:10 S-1チェルノプイリ周辺地域における小児甲状腺がんの特徴、および福島との相違について高村昇（長崎大学）チェルノプイリと福島の森林：放射性セシウムの循環移動ヴァシル・ヨシェンコ（福島大学）.................................................................................................................180チェルノプイリと福島における河川網を介した放射性物質の動態五十嵐康記（福島大学）、 SATREPS課題 「チェルノプイリ災害後の環境管理支援技術の確立」参加メンバー ……………………181チェルノプイリと福島第一原発事故後の海洋環境中の放射性セシウム濃度の変遷高田兵衛（福島大学）…環境放射能研究所副所長:高橋隆行Takayuki Takahashi , Vice Director , IER Closing Remarks 16:25 9:00 9:00 12:00 13:00 Hirofumi Tsukada , Director , IER Overview 13:05 13:35  S-2 14:00 S-3 14:35 -休　憩- 14:45  S-4 15:20  S-5 15:40  S-6 16:00総合討論閉会疾拶16:25 16:00 Q & A 7 P-16 Development of quantitative analysis method using radon to elucidate complex groundwater processes unique in limestone area Shunya Nakasone, Naofumi Akata P-17 The evaluation of radioactive cesium dynamics in forest-stream ecosystem of mountainous watershed Yuiko Chino, Yoshito Oyama, Takashi Gomi, Hiroto Toda . Changes in Cs-137 concentration in dissolved form and sediment in the rivers in the difficult-to-return zone and the surrounding area, and their factors (Distribution coefficient of Cs-137 in between dissolved form and sediment) P-18 P-1 Catchment scale estimation of current and future water balance in the Chernobyl Exclusion Zone in Ukraine P-2 Yasunori Igarashi, Mark Zheleznyak, Hlib Lisovyi, Yoshifumi Wakiyama, Yuichi Onda, Kenji Nanba, Alexei Konoplev, Gennady Laptev, Dmitry Samoilov, Volodyill Damiyanovich, Serhii Kirieiev ......................39 Time series of 137Cs activity concentration in irrigation waters collected from Kami-oguni River and Oogaki dam in Fukushima Hirofumi Tsukada P-3 Temporal variation in 137Cs concentrations in the Niida River water during a rainstorm event Takuya Niida, Yoshifumi Wakiyama, Alexei Konoplev . P-4 Radiocesium concentrations in experimentally cultured carp, other fishes, and sediments of an irrigation pond in Koriyama City Misaki Usuki, Yuki Inoue, Tomomi Yanagita, Keiichi Sasaki, Kenji Nanba, Toshihiro Wada .......................... 42 Seasonal trend of Cs-137 concentration and water quality in Abukuma River waters Shota Moritaka, Toshihiro Wada, Kenji Nanba . P-5 P-6 Vertical distribution of 137Cs in bottom sediments represents long-term dynamics of water contamination: Fukushima and Chernobyl Alexei Konoplev, Yoshifumi Wakiyama, Toshihiro Wada, Gennadyi Laptev, Valentin Golosov, Maxim Ivanov, Mikhail Komissarov, Yasunori Igarashi, Kenji Watanabe, Azusa Goto, Kenji Nanba The mechanisms of dissolved radiocesium discharge through stream system in a headwater forest catchment P-7 Hiroaki Kato, Satoru Akaiwa, Tomoki Shinozuka, Zul Hilmi Saidin, Hikaru Iida, Yuichi Onda, Tadafumi Niizato P-8 P-9 Comparative behavior of radiocesium and tritium along a river-to-coast transect Hyoe Takata, Michio Aoyama, Toshiya Tamari, Junji Yamanaka Temporal variations in riverine 137Cs and 129I concentrations under high-flow events Yoshifumi Wakiyama, Masumi Matsumura, Tetsuya Matsunaka, Shigekazu Hirao, Kimikazu Sasa . P-10 Development of a model to reproduce 137Cs dissolution from dam lake sediment considering temperature and dissolved oxygen condition Hideki Tsuji, Seiji Hayashi, Hironori Higashi, Kazuyuki Sakuma, Kazuya Yoshimura, Hironori Funaki, Takahiro Nakanishi, Tadahiko Tsuruta . P-11 Study on transport of radionuclides in watershed environment Takahiro Nakanishi, Tadahiko Tsuruta, Hironori Funaki, Kazuyuki Sakuma, Tomisato Miura, Mitsuaki A. Yoshida . P-12 Dynamics of particulate radiocaesium in river and coastal area in Fukushima Prefecture Tatsuo Aono, Takahiro Nakanishi . P-13 P-14 Evaluation of dissolved 137Cs discharge characteristics from a forested catchment of the Ohta River Kazuyuki Sakuma, Kazuya Yoshimura, Takahiro Nakanishi, Hironori Funaki, Tadahiko Tsuruta, Kotaro Ochi, Seiji Hayashi, Hideki Tsuji, Hirokazu Ozaki Radiocesium fate and transport in the soil-water environment in the proximity of the Fukushima Daiiich Nuclear Power Plant Cameron Udy, Tom Johnson, Ralf Sudowe, Yoshifumi Wakiyama, Kenji Watanabe, Alexei Konoplev . P-15 Mapping of water age in a forested headwater catchment after the Fukushima Dai-ichi Nuclear Power Plant accident Koichi Sakakibara, Maki Tsujimura, Sho Iwagami, Kosuke Nagano, Yuichi Onda Yukio Takeuchi, Keisuke Taniguchi, Hirotsugu Arai, Hirofumi Yoshita, Kazuki Fujita, Yuichi Onda .................... 56 Study on the discharge of radioactive cesium from a forest basin in northern Fukushima and the sedimentation mechanism in the reservoir P-20 Takuya Kawai, Nobuhito Ohte, Naoto Nihei, Toshihiro Wada Fractional analysis of radiocesium in pond water in difficult- to-return zone Tomijiro Kubota, Hirofumi Tsukada . P-21 Radiocaesium dynamics in forested watersheds in Fukushima Prefecture Keisuke Taniguchi, Yukio Takeuchi, Kazuki Fujita, Terumi Dohi, Seiji Hayashi, Takayuki Kuramoto, Naoki Nomura, Tatsuo Aono . P-22 Migration behavior of radiocesium in river systems in the coastal area of Fukushima Prefecture Deddy Irawan Permana Putra, Shinya Ochiai, Takahiro Nakanishi , Tadahiko Tsuruta, Seiichi Tomihara, Shun Watanabe, Kyuma Suzuki, Seiya Nagao P-133 Current status and issues of decontaminated paddy field resulted from rice production experiments in mountainous area P-134 Hiroaki Matsuoka, Yoshinari Suzuki, Masaaki Saito, Kazuki Togami, Osamu Nagata, Takuro Shinano................ 61 Horizontal distribution of radiocesium in soil on farmland after decontamination in evacuation zones Takashi Saito, Tomoaki Nemoto, Tsukasa Ono, Minoru Tanigaki .
Ocean
P-23 Spatio-temporal variability of radiocesium concentration in coastal sediment of Fukushima Shotaro Suzuki, Yosuke Amano, Akira Matsumoto, Kyoichi Kamiyama . P-24 P-25 P-26 P-27 Tracing the sources of Pu and Hg in the deep-sea sediments using Pu and Hg isotopes Wang Zheng, Holger Hintelmann, Wei Dong, Jian Zheng . Pu and Cs isotopes in the sediment cores of the Northwest Pacific after the Fukushima nuclear accident Fenfen Wang, Wu Men, Jian Zheng, Shaoming Pan . Study of radiocesium contamination of marine fishes in Fukushima Prefecture Shotaro Suzuki, Yosuke Amano, Kyoichi Kamiyama, Toshihiro Wada Elucidation of the migration ecology of fish around the Fukushima Daiichi Nuclear Power Plant for risk assessment of radioactive contamination of fish Takuji Noda, Toshihiro Wada, Hiromichi Mitamura . P-28 Relationship between radiocesium concentration and trophic position of fish in Matsukawa-ura lagoon, Fukushima Prefecture Akira Matsumoto, Yoshiaki Morioka, Manabu Yamada, Toshiyuki Sato, Toshihiro Wada ........................................68 Effect of radiocesium-bearing microparticles from suspended particles on the solid-water distribution coefficient P-29 Hikaru Miura, Takashi Ishimaru, Yukari Ito, Jota Kanda, Yuichi Kurihara, Atsushi Kubo, Daisuke Tsumune, Hirofumi Tazoe, Yoshio Takahashi
Poster
River and Lake
9 P-19 P-30 Evaluations of water discharge and material transports to coastal ocean via submarine groundwater discharge using radionuclides as chemical tracers Saki Katazakai, Jing Zhang, Tatsuo Aono . P-31 P-32 Estimate of 137Cs derived from FNPP1 transport amount and time scale into the Sea of Japan Yayoi Inomata, Michio Aoyama Reconstruction of distribution of Fukushima-derived radiocesium in the North Pacific Ocean in 2014 by means of observation and dataset Yuichiro Kumamoto, Yasunori Hamajima, Michio Aoyama . Flume experiment for deposition of muddy sediment under waves Naofumi Yamaguchi, Tomohiro Sekiguchi, Tetsuya Shinozaki P-33 P-34 Radiocesium-rich microparticles in plankton-net samples off Fukushima Prefecture Jota Kanda, Yukari Ito, Takashi Ishimaru P-35 Development of biomonitoring method for radionuclides using mussels Naoko Murakami-Sugihara, Kotaro Shirai, Hirofumi Tazoe, Kaoruko Mizukawa, Hideshige Takada, Takeyasu Yamagata, Shigeyoshi Otosaka, Hiroshi Ogawa P-36 Behaviors of analog elements of transuranic nuclides in the sea regions around Japanese archipelago Kazuhiro Norisuye, Daichi Asanuma, Shun Kakuta, Tohru Fukazawa, Ryo Hashimoto . Transport of suspended radiocesium in coastal area off Fukushima Shigeyoshi Otosaka, Takashi Suzuki, Tadahiko Tsuruta, Toshiharu Misonou, Terumi Dohi, Yoshihisa Mino, Chiho Sukigara, Yukari Ito, Jota Kanda, Tahashi Ishimaru P-37 P-38 Study on supply process of radioactive cesium from Uda River / Matsukawa-ura to the ocean Daisuke Tsumune, Hikaru Miura, Seiji Hayashi, Hideki Tsuji, Yasunori Hamajima, Michio Aoyama ................... 78
Ecosystem and Effect
P-39 Preliminary investigation on radiocesium dynamics research using moss Mamoru Sato, Daisuke Takata . P-40 Relationships between 137Cs concentration of masu salmon and crucian carp and indicators for 137Cs contamination in environment at lakes Yuto Funaki, Kazuyoshi Takasaki, Wataru Teramoto, Tadahiro Sohtome P-41 Evaluation of vegetation index in Abukuma River basin for estimating soil erosion Edea Loa, Seiki Kawagoe . Radiocesium concentrations and food habits of Japanese eel in Fukushima Prefecture Yushi Fujita, Masato Suda, Yuma Furuta, Kenji Watanabe, Shingo Kaneko,Kenji Nanba, Toshihiro Wada ......... 82 Cs-137 uptake and excretion of Japanese dace under different salinity conditions using litter-derived Cs- 137 containing water P-42 P-43 Naoto Kanagawa, Keiichi Sasaki, Toshihiro Wada, Kenji Nanba . P-44 Accumulation of radiocaesium in bryophytes Chieko Otsuki, Hirofumi Tsukada . P-45 Strong contrast of cesium radioactivity between marine and freshwater fish in Fukushima Toshihiro Wada, Alexei Konoplev, Yoshifumi Wakiyama, Kenji Watanabe, Yuma Furuta, Daigo Morishita, Gyo Kawata, Kenji Nanba . P-46 Effect of the formation of the micro-terracetts on the Cs-137 and sediment transport on sandy granitic soil in Yamakiya decontaminated hillslopes P-47 Yuichi Onda, Yoshifumi Wakiyama, Syohei Kozuka Temporal change of radiocesium leaching from forest canopies following the Fukushima Daiichi Nuclear Power Plant accident Hiroaki Kato, Tomoki Shinozuka, Zul Hilmi Saidin, Hikaru Iida, Satoru Akaiwa, Yuichi Onda, Vasyl Yoschenko . P-48 Estimation of downward migration of radiocesium in forest soils using zero-tension lysimeter Junko Takahashi, Takuya Sasaki, Daichi Hihara, Yuichi Onda, Hirofumi Tsukada P-49 Mutation rate evaluation using microsatellite marker P-50 P-51 Establishment of a dose response curve for dicentric chromosome analysis in wild boar Hiroko Ishiniwa, Donovan Anderson, Yohei Fujishima, Kei Okuda, Mitsuaki Yoshida, Toshiya Inaba, Akiko Nagamachi, Kenji Nanba, Tomisato Miura P-52 P-53 P-54 P-55 P-56 P-57 P-58 Effects of radionuclide exposure on microbiome of wild boar P-59 Jim Beasley, Kenji Nanba, Sarah Chinn, Kakeru Ambai, Diana Lafferty . Determination of radiation dose to Large Japanese Field Mice in the vicinity of Fukushima Daiichi Nuclear Power Plant Mariah Davis, Thomas Johnson, Tsugiko Takase, Yuki Odagiri, Yusuke Mitsuyasu, Hisashi Shinoda, Toshitaka Oka, Hiroko Ishiniwa P-60 Estimation of biomass and stocks biologically mobility radionuclides using methods of processing aboveground and remote sensing data for radioactively contaminated forests in Ukraine D. Holiaka, H. Kato, V. Yoschenko, Y. Onda, Y. Igarashi, K. Nanba, P. Dyachuk, R. Zahorodnuk .............................100 Elucidation of transfer pathways of radiocesium in terrestrial invertebrates Sota Tanaka, Hotaru Kakinuma, Tarô Adati, Mariko Atarashi-Andoh, Jun Koarashi Search for wild species of the genus Vigna without accumulating cesium at the shoot apex Yusaku Noda, Jun Furukawa . P-62 P-63 Radiocesium concentrations in wild boar captured within 20 km of the Fukushima Daiichi Nuclear Power Plant P-64 Makiko Orita, Noboru Takamura, Cui Limeng, Yasuyuki Yaira, Yumiko Yamada, Hirofumi Tsukada .....................103 Elucidation of radioactive contamination level and establishment of extermination methods of invasive channel catfish toward the restoration of Fukushima' s inland water fisheries Junichi Takagi, Toshihiro Wada, Hiromichi Mitamura P-65 Elucidation of radiocaesium migration characteristics in freshwater fish inhabiting upstream Ota River Wataru Teramoto, Toshihiro Wada, Yumiko Ishii, Seiji Hayashi, Kenji Nanba . Shingo Kaneko, Yuta Murayama, Yoshito Watanabe Analysis of genetic changes in cancer induced by low dose rate radiation -Time course-dependent analysis of chromosomal abnormalities in hematopoietic tissues of irradiated mice- Kodai Suga, Ikue Asari, Masato Umetsu, Yuma Imai, Yohei Fujishima, Valerie Swee Ting Goh, Naomi Sasaki, Kentaro Ariyoshi, Tomisato Miura, Yutaka Yamada, Mitsuaki Yoshida . Comparative studies between field and irradiation experiments for elucidation of environmental effects by the Fukushima Daiichi Nuclear Power Plant accident Yoshito Watanabe, Vasyl Yoschenko, Shoichi Fuma, Kouichi Maruyama, Yutaka Yamada Radiocesium bioavailability and radiocesium-bearing microparticles in aquatic insects of Ota River Yumiko Ishii, Jaeick Jo, Seiji Hayashi, Hikaru Miura, Daisuke Tsumune, Toshihiro Wada, Tsutomu Kanasashi, Kenji Nanba, Wataru Teramoto, Tadahiro Sohtome, Rie Saito . Multi-sources images time-series for landscape dynamics analysis in rural areas after Fukushima accident Lissak Candide, Onda Yuichi, Kato Hiroaki, Preux Thibaut, Dufour Simon Contribution of K transporters to Cs uptake and accumulation in rice Nathalie Leonhardt, Satomi Kanno, Shigeto Fujimura, Takuro Shinano, Jun Furukawa Characteristics of chemical compositions of xylem sap in a pine forest under environmental changes Sun Xinchao, Onda Yuichi Determination of local ecological factors on soil-to-plant transfers in Fukushima forest ecosystems Vasyl Yoschenko, Alexander Brandl, Jian Zhang . P-61 P-66 DNA analyses to estimate life-time dose from radiation exposures estimation of life-time doses to wild boar using dicentric chromosome analysis Donovan Anderson, Tomisato Miura, Yohei Fujishima, Kei Okuda, Kenji Nanba, Thomas Hinton, Hiroko Ishiniwa . P-67 P-68 P-69 P-70 P-71 P-72 accident restricted area Daiji Endoh, Hiroko Ishiniwa, Misaki Tanaka, Manabu Onuma, Nobuyoshi Nakajima . Current occurrence of truffles and truffle-like fungi in forests near the Fukushima nuclear power plant accident P-73 P-74 Takamichi Orihara, Hiromi Sasaki, Muneyuki Ohmae, Hiroko Ishiniwa . Population genetic demography of mountain stream fishes under reduced human activities in the difficult- to-return zones, Fukushima, Japan Yoshiaki Tsuda, Masaki Akaike, Keisuke Yumoto, Uchu Yamakawa, Faulks Leanne Kay, Shingo Kaneko, Toshihiro Wada P-75 Mechanisms of radiation effects mediated by secreted factors Genro Kashino, Kentaro Ariyoshi, Jun Kumagai P-76 Radiostrontium monitoring of fish bone from river ecosystem in Fukushima Zin' ichi Karube, Ryoichi Fujino, Takummi Nagami, Hirofumi Tazoe P-77 Measurement and analysis of radioactive cesium in genitals of cats captured in Namie Town, Fukushima Prefecture Youhei Fujishima, Yasushi KIno, Takumi Ono, Kentaro Ariyoshi, Mitsuaki Yoshida, Kosuke Kasai, Tomisato Miura, Akira Nakata P-78 Age factors in uptake and excretion of radioactive material using raccoon bone and cartilage Yoshinaka Shimizu, Takahashi Atsushi, Miura Tomisato, Shinoda Hisashi . P-79 Comprehensive analysis of radiation effect(s) in non-human primate exposed in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident Masatoshi Suzuki, Satoru Endo, Yuki Matsutani, Yasushi Kino, Takumi Ono, Toshitaka Oka, Atsushi Takahashi, Yoshinaka Shimizu, Hisashi Shinoda, Tomisato Miura, Kentaro Ariyoshi, Mitsuaki Yoshida, Manabu Fukumoto . Development of method for evaluating transgenerational effects focusing on meiosis Akifumi Nakata, Valerie Goh Swee Ting, Kosuke Kasai, Hirofumi Tazoe, Kentaro Ariyoshi, Hideaki Yamashiro, Mitsuaki Yoshida, Tomisato Miura . Effect of chronic radiation exposure associated with Fukushima accident on the freezability and fertility of P-80 P-81 the Large Japanese Field Mice (Apodemus speciosus) sperm Hideaki Yamashiro, Akifumi Nakata, Kosuke Kasai, Kentaro Ariyoshi, Mitsuaki Yoshida, Tomisato Miura .......121 Annual dynamics of the biotransfer of radio-Cesium in forest ecosystem
Masashi Murakami, Nobuhiro Ishii . P-82 Development an approach to therapy for radition injury using Muse cell Yohei Fujishima, Takuma Hashimoto, Yusuke Urushihara, Li Gen, Mari Dezawa, Yoshio Hosoi ...............................107 Investigation of biological behavior of radiocaesium in the body of Japanese macaque Yusuke Urushihara, Masatoshi Suzuki, Yoshikazu Kuwahara, Yasushi Kino, Tsutomu Sekine, Hisashi Shinoda,Tatsuo Aono, Manabu Fukumoto, Yoshio Hosoi Population structure of wild boar in Fukushima Prefecture including evacuation zone Rie Saito, Natsuko Kondo, Yui Nemoto, Reiko, Kumada, Masanori Tamaoki . Pre- and post-accident 14C activities in tree rings near the Fukushima Daiichi Nuclear Power Plant Tetsuya Matsunaka, Kimikazu Sasa, Masumi Matsumura, Shigekazu Hirao, Yoshifumi Wakiyama, Keisuke Sueki . Elucidation of the cesium absorption and transport pathway of major crops (rice and soybean) Miku Kawabata, Ayano Amemiya, Jun Furukawa, Hiroki Rai Development of estimation method for genome alteration in wild mice living in the Fukushima nuclear Population genetic structure of Asian black bear in Fukushima Prefecture P-83 Yui Nemoto, Rie Saito, Reiko Kumada, Natsuko Kondo, Yoshiki Morimitsu, Masanori Tamaoki .............................123 P-135 The effects of farming interruption, decontamination and resumption on aquatic insects in the rice paddy fields by theaccident at the TEPCO Fukushima Daiichi Nuclear Power Plant Toshimasa Mitamura, Wakana Endo, Nobuhiro Matsuki, Akira Yoshioka, Ken Tabuchi .............................................. 124
Measurement and Analysis
P-84 Precise and accurate measurement of uranium isotope ratios at nanogram level using multi Daly collectors of MC-ICP-MS P-85 Murugan Rajamanickam, Sarata Kumar Sahoo, Tatsuo Aono . Analysis of in vivo kinetics of radiocaesium in Japanese dace tribolodon hakonensis reared individually using CsI (Tl) Scintillator P-86 P-87 P-88 P-89 P-90 P-91 P-92 P-93 P-94 Yoshitaka Shiroma, Syunya Nakasone, Shigekazu Hirao . P-95 Establishment of a novel cytogenetic dosimetry method using chromosome condensation inhibitors Yu Abe, Mitsuaki A. Yoshida . P-96 Analysis of temporal variations for Cs concentration and bio-aerosol in Tsukuba botanical garden Ishizuka Masahide, Tanaka Kuniaki, Miyamoto Erika, Hatano Yuko, Hosaka Kentaro, Kita Kazuyuki, Maki Teruya, Igarashi yasuhito P-97 Abundance and distribution of radioactive cesium-rich microparticles released from the Fukushima Daiichi Nuclear Power Plant into the environment Ryohei Ikehara, Kazuya Morooka, Mizuki Suetake, Tatsuki Komiya, Eitaro Kurihara, Masato Takehara, Ryu Takami, Shinya Yamasaki, Satoshi Utsunomiya . P-98 Local coordination structures of Sr in calcite and aragonite Kazuya Tanaka, Shinya Yamasaki Development of NORM sources for educational application Takeshi Iimoto, Hiromi Koike, Hasan Md. Mahamudul . P-99 P-100 Calibration test on instrument for natural radionuclides in the atmosphere Kazuki Iwaoka, Yuki Tamakuma, Masahiro Hosoda, Naofumi Akata, Shinji Tokonami ...................................................141 Measurement and application studies on the environmental actinides Z. Huang, Y. Ni, H. Wang, J. Zheng, S. Yamazaki, A. Sakaguchi, X. Long, S. Uchida . Precision analysis of tritium using low-background liquid scintillation counter Naofumi Akata, Hirofumi Tazoe, Chutima Kranrod, Kenso Fujiwara, Toshiharu Misonou, Haruka Kuwata, Shigekazu Hirao . Development of precise analysis Cs-134/Cs-137 ratio using thermal ionization mass spectrometer Hirofumi Tazoe, Yoshitaka Takagai . Fundamental research on tracer use of natural radionuclide Masahiro Hosoda, Shigekazu Hirao, Yuki Tamakuma, Naofumi Akata, Shinji Tokonami . Feasibility of Cs-135 measurements using accelerator mass spectrometry Maki Honda, Alexander Wieser, Johannes Lachner, Martin Martschini, Peter Steier, Alfred Priller, Oscar Walther, Robin Golser, Keisuke Sueki, Aya Sakaguchi . Monitoring of continental fallout in Okinawa Prefecture Masamune Endo, Keiichi Sasaki,Tatsuma Sato, Tsuneo Fujita . Activity concentration of radiocaesium in self-consumed crops collected from cancelled evacuation-zone Mihoko Kikuchi, Hirofumi Tsukada Detection of 60Co released from the 2011 Fukushima Daiichi Nuclear Power Plant accident Yusuke Okizawa, Hirofumi Tsukada Radioactive cesium uptake in Koshiabura (Eleutherococcus sciadophylloides) Jun Furukawa, Masaki Tamaoki, Takafumi Mizuno . P-101  Development of a gamma-ray radiation source by using a dual nozzle type 3D printer Takashi Saito, Yuya Koike, Horofumi Tazoe . P-102   Development of evaluating radiation exposure dose in association with nuclear disaster by PHITS code into which mesh-type reference computational phantoms (MRCPs) is incorporated and MRCPs in represented with high quality of organ/tissues of human body Minoru Sakama, Takuya Saze, Naofumi Akata . P-103   Survey of radiation and earthquake disaster education for children who have not experienced the Great East Japan Earthquake, and search for optimal educational content Takuya Saze, Minoru Sakama, Naofumi Akata . P-104   Trouble shooting for ESR dosimetry of racoon teeth living in evacuation zone after Fukushima Daiichi Nuclear Power Plants accident -Identification of interfering factors- Atsushi Takahashi, Toshitaka Oka, Kazuma Koarai, Hisashi Shinoda Analysis of volcanic activity and radon and progeny nuclide concentrations in Sakurajima P-105 Kenta Higuchi, Masahiro Hosodo, Shinji Tokonami, Suminori Akiba . P-106    Examination of submarine groundwater discharge search method by measurement of radon concentration in water Masahide Furukawa, Yoshitaka Shiroma, Masahiro Hosoda, Naofumi Akata, Tetsuya Sanada, Shunya Nakasone, Akinobu Ishimine, Kaori Nakamura, Shinji Tokonami P-107   Study of the deposition situation by the isotope analysis of environmental samples near the Fukushima Daiichi Nuclear Power Plant Haruka Minowa, Hideki Yoshikawa, Hirofumi Tazoe . P-108   Method for checking the sensitivity of exhaust monitors at radiation facilities using radon in the environment Yumi Yasuoka, Shinji Tokonami, Masahiro Hosoda, Takeshi Iimoto, Takahiro Mukai ..............................................149 P-109  Development of pretreatment and analysis for environmental samples containing radiocaesium - Preliminary ToF-SIMS analysis of Cs isotope ratio in the microparticle - Hisaya Tagomori, Hidehisa Kawamura, Keiichi kusano, Terumi Dohi . Mineralogical study of transporting radiocesium sorbed media P-110 Hiroki Hagiwara, Hiromi Konishi . P-111    Environmental behaviors of radioactive Cs studied by Cs DGT Takumi Saito, Masafumi Fukuoka, Kenso Fujiwara P-112  Evaluation of sorption condition of polyvalent metal ions by multidimensional spectroscopic approach Takayuki Sasaki, Taishi Kobayashi, Kenso Fujiwara, Terumi Dohi, Kazuki Iijima . P-136    Method development and radioactivity analysis of strontium-90 in environmental samples by ICP-MS Chen Fei, Zhang Zhen, Jiao Ling, Tazoe Hirofumi, Yang Guosheng ..............................................................................154
Speciation Radiochemistry
P-113  Study of stability of complexes containing radioactive metal ions using quantum chemical simulation Tsugiko Takase, Kousei Wadayama, Syunsuke Nakamura, Dai Oyama . P-114   Studies on nickel(II) and cobalt(III) complexes of an isomeric polyazamacrocyclic chelator and its N-pendent derivative for the application in radioactive waste decontamination Tapashi G. Roy, Saroj K.S. Hazari, Benu K. Dey, Debashis Palit, Lucky Dey, Zinnat A. Begum, Ismail M.M. Rahman P-115  Studies on the distribution and migration characteristics of actinides in typical karst environment Hai Wang, Jian Zheng, Detao Xiao, Ming Liu, Xiangyang Luo . P-116  Long-term prediction for collective radioactive particles by a bayesian advection diffusion equation Yusuke Uchiyama, Yuko Hatano P-117   Application of radon and its decay products monitor using two-filter method as a monitor for airborne radionuclides under nuclear disaster Yu Igarashi, Takeshi Iimoto, Masahiro Hosoda P-118 Thoron infiltration through filters used for diffusion-type radon-thoron detectors Yasutaka Omori, Yuki Tamakuma, Takahito Suzuki, Eka Djatnika Nugraha, Miki Arian Saputra, Masahiro Hosoda, Shinji Tokonami P-119   Analysis of nonvolatile nuclides in radioactive particles released from Fukushima Daiichi Nuclear Power Plant accident Junya Igarashi, Jian Zheng, Zijian Zhang, Kazuhiko Ninomiya, Yukihiko Satou, Miho Fukuda, Youyi Ni, Tatsuo Aono, Atsushi Shinohara P-120 Analyses for physicochemical properties in radioactive particles by a synchrotron x-ray: Part 2 Yukihiko Satou, Keisuke Sueki . P-121    Development of chemical separation method of Np for the determination of Np-237 in environmental by accelerator mass spectrometry Y. Hayakawa, N. Matsumura, A. Sakaguchi, A. Nakajima, K. Teranishi, R. Morita, A. Yokoyama ..........................163 P-122  Removal of metal ion pollutants from waste water by using porous amorphous Fe2O3 Bashir Ahmmad Arima, M. Ferdous Alam, Zinnat A. Begum, Ismail M.M. Rahman .................................................164 Remediation of radiocesium contaminated soil P-123 Zinnat Ara Begum, Ismail M.M. Rahman, Hiroshi Hasegawa P-124  Analysis of effects of radioactive particles on crop cultivation Naoto Nihei, Kazuya Yoshimura . P-137  Facilities development for analysis of radionuclides in environmental samples collected from Ruppur Nuclear Power Plant (RNPP), Bangladesh M. Safiur Rahman, M.M.A Mollah, S.M.A. Salam, M.A.B. Siddique, M.R. Zaman, G. Yang, H. Tazoe ................167
Modeling
P-125  Studies on the effective dose for public calculated by air dose rate Yuya Endo, Katsuhiko Yamaguchi, Tsugiko Takase, Yasuhiro Uezu, Hirofumi Tsukada ...................................................168 P-126 The temporal variations of radio-cesium concentration in air in Okuma Shigekazu Hirao . P-127    Measurement of emission flux of radioactive cesium to the atmosphere Olivier Masson, Kita Kazuyuki, Denis Maro, Harada Koshi, Hayashi Naho, Minami Kohtaro, Hatano Yuko, Igarashi Yasuhito . Evaluation of dose from handling radionuclides contaminated materials P-128 Kazuji Miwa, Takeshi Iimoto, Shigekazu Hirao P-129   Modeling of time series data of radioactive cesium concentration in lake water of Lake Onuma on Mt. Akagi Yukiko Okada, Eiichi Suetomi, Takafumi Uchiyama, Masakiyo Fujita, Yuko Hatano .....................................................172 P-130   Development of mathematical model for long-term prediction of radioactive cesium concentration in airborne particulate matter Eiichi Suetomi, Yukiko Okada, Naoto Hagura, Takafumi Uchiyama, Yuko Hatano .............................................................173 Prediction of radiocesium behavior based on concentration profile and mass transfer simulation P-131 Tetsuo Yasutaka, Koki Matsushita P-132 Radiocesium resuspension caused by the decontamination and demolition work at a special reconstruction and revitalization base of the difficult-to-return zone in Tomioka Town, Fukushima Prefecture Yasuyuki Taira, Masahiko Matsuo, Shigekazu Hirao 16ポスター発表
河川・湖沼分野
P-1チェルノブイリ規制区域を対象とした流域スケールでの現在・将来気候下の水収支五十嵐康記、マークザレズニヤク、グレップリソプイ、恩田裕一、脇山義史、アレクセイ　コノブリョフ、難波謙二、ゲナディ　ラブテフ、ポルディミル　デミャノピッチ、ドミロリ　サモイロフ、セルゲイ　キリエフ福島県上小国川と大柿ダムにおける137Cs濃度の経時変化P-2 P-3 P-4 P-5 P-6 ...塚田祥文台風接近時における新田川河川水の137Cs濃度の経時的変化新井田拓也、脇山義史、Alexei Konoplev  .郡山市のため池における給餌資殖試験コイ，その他魚類，および堆積物の放射性セシウム濃度薄実咲、井上雄貴、柳田知美、佐々木恵一、鷲波謙二、和田敏裕…阿武隈川における河川水中のCs-137濃度と水質の季節変動森高祥太、和田敏裕、舞波謙二Vertical distribution of 137Cs in bottom sediments represents long-term dynamics of water contamination: Fukushima and Chernobyl P-7 P-8 P-9 P-10 Alexei Konoplev, Yoshifumi Wakiyama, Toshihiro Wada, Gennadyi Laptev, Valentin Golosov, Maxim Ivanov, Mikhail Komissarov, Yasunori Igarashi, Kenji Watanabe, Azusa Goto, Kenji Nanba ....................... 44森林源頭部における水系を通じた浴存態放射性セシウムの流出メカニズムの解明加藤弘充、赤岩哲、篠塚友輝、飯田光、恩田裕一、新里忠史…河川から海洋への寄与と天然起源トリチウムを考慮した福島沿岸のセシウムとトリチウムの举動高田兵衛、青山道夫、玉利俊哉、山中潤二出水時の河川水の137Csおよび129I濃度の時系列変化脇山義史、松村万寿美、松中哲也、平尾茂一、笹公和水温・浴存酸素濃度環境を考慮したダム湖底質からの137Cs溶出現象再現モデルの情築辻英樹、林誠二、東博紀、佐久間一幸、吉村和也、舟木泰智、中西貴宏、鶴田忠彦…流域環境における放射性物質移行挙動の解明中西貴宏、鶴田忠彦、舟木泰智、佐久間一幸、三浦富智、吉田光明河川-沿岸における粒子態放射性セシウムの形態に関する研究青野辰雄、中西貴宏… P-11 P-12 P-13 P-14 P-15 P-16 P-17 P-18山地流域における渓畔林－渓流生態系における放射性セシウム動態評価. . .千野結子、大山義人、五味高志、戸田浩人…帰還困難区域及びその周辺の河川における溶存態及び河床土の放射性セシウムの濃度変化とその要因（溶存態－河床土のCs-137分配係数）竹内幸生、谷口圭輔、新井宏受、吉田博文、藤田一輝、恩田裕一…福島県北部森林流域からの放射性セシウムの流出と貯水池における堆積メカニズムに関する研究川井拓哉、大手信人、二瓶直登、和田敏裕P-19 P-20久保田富次郎、塚田祥文P-21福島県森林集水域における放射性セシウムの動態解析研究谷口圭輔、竹内幸生、藤田一輝、土肥輝美、林誠二、倉元隆之、野村直樹、青野辰雄福島県沿岸域の河川水系における放射性セシウムの移行動態P-22 Deddy Irawan Permana Putra、落合伸也、中西貴宏、鶴田忠彦、冨原聖一、渡辺峻、鈴木究真、長尾詠也P-133中山間地域における除染後水田での水稲栽培試験からみる現状と課題松岡宏明、鈴木芳成、齋藤正明、戸上和樹、永田修、信濃卓郎P-134　避難指示区域等の除染後農地における土壌中放射性セシウム等の分布実態...
海洋分野
P-23福島県沿岸域における海底土の放射性セシウム濃度の時空間的変動鈴木翔太郎、天野洋典、松本陽、神山亨一. . . . P-24 Tracing the sources of Pu and Hg in the deep-sea sediments using Pu and Hg isotopes Wang Zheng, Holger Hintelmann, Wei Dong, Jian Zheng . P-25 P-26 P-27 P-28 P-29 P-30 P-31 P-32 P-33 P-34 P-35 P-36 P-37 P-38宇多川・松川浦から海洋への放射性セシウムの供給過程の解明津旨大輔、三浦輝、林誠二、辻英樹、浜島靖典、青山道夫Pu and Cs isotopes in the sediment cores of the Northwest Pacific after the Fukushima Nuclear accident Fenfen Wang, Wu Men, Jian Zheng, Shaoming Pan .福島県沿岸域における魚類の放射性セシウム酱積過程の解明66鈴木翔太郎、天野洋典、神山亨一、和田敏裕魚類の放射能汚染のリスク評価に向けた原発周辺海域の魚類の移動生態の解明野田琢嗣、和田敏裕、三田村啓理福島県松川浦における魚類の放射性セシウム濃度と栄養段階との関係松本陽、守岡良晃、山田学、佐藤利幸、和田敏裕熊川沖の懸濁粒子中のセシウム含有粒子中のセシウムが固液分配に与える影響評価三浦輝、石丸隆、伊藤友加里、神田譲太、栗原雄一、久保敦、津旨大輔、田副博文、高橋嘉夫……………… 69放射性核種を化学トレーサーに用いた海底湧水による沿岸海域への水・物質輸送状況の解明片境紗希、張勁、青野辰雄 …日本海及び北太平洋における福島原子力発電所由来の放射性セシウム濃度の輸送の時定数と輸送量の推定猪股弥生、青山道夫.現場観測とデータセット作成による2014年北太平洋全域における福島事故起源放射性セシウムの分布再現熊本雄一郎、浜島猪典、青山道夫波浪影響下での泥質堆積物の動態に関する造波水路実験73山口直文、関口智寛、篠崎鉄哉福島県沖で採集されたプランクトンサンプル中の高セシウム粒子神田穣太、伊藤友加里、石丸隆ムラサキイガイを用いた放射性核種のバイオモニタリング手法の開発杉原奈央子、白井厚太朗、田副博文、水川薫子、高田秀重、山形武靖、乙坂重嘉、小川浩史............................. 75日本周辺海域における超ウラン核種アナログ元茶群の動態76則末和宏、浅沼大地、角田隼、深澤徹、橋本燎…沈降粒子特性の相互比較による陸域-海域間の懸濁態放射性核種の輸送過程の解明乙坂重嘉、鈴木崇史,鶴田忠彦、御園生敏治、土肥輝美、三野義尚、鶴柄千穂、伊藤友加里、神田穣太、石丸隆…太田川森林域からの落存態137Cs流出特性評価佐久間一幸、吉村和也、中西貴宏、舟木泰智、鶴田忠彦、越智康太郎、林誠二、辻英樹、尾崎宏和……… 51 Radiocesium fate and transport in the soil-water environment in the proximity of the Fukushima Daiich Nuclear Power Plant Cameron Udy, Tom Johnson, Ralf Sudowe, Yoshifumi Wakiyama, Kenji Watanabe, Alexei Konoplev .................. 52福島第一原子力発電所事故の影響を受けた山地森林における環境水の滞留時間マッビング精原厚一、辻村真貴、岩上翔、長野倖介、恩田裕一…石灰岩地域特有の複雑な地下水プロセスを解明するためのラドンを用いた定量解析手法の開発仲奈根峻也、赤田尚史

生態系・影響分野
P-39 P-40 P-41 P-42 P-43 P-44 P-45 P-46 P-47 P-48福島第一原子力発電所事故後の森林樹冠からリーチングされる放射性セシウムの時間変化の解明加藤弘兗、篠塚友輝、飯田光、ズル　サイディン、赤岩哲、恩田裕一、ヴァシル　ヨシェンコ……………… 87ゼロテンションライシメータを用いた土壌中放射性セシウムの下方移行量の評価P-49高橋純子、佐々木拓哉、日原大智、恩田裕一、塚田祥文.照射実験個体を対象とした塩基配列突然変異の検出法の開発ーマイクロサテライトマーカーによる突然変異率評価一P-50 89低線量率放射線により誘発された癌の遺伝学的変化の解析-放射線照射したマウスの造血系組織における染色体異常の経時的変化の解析-菅弘大、浅利郁江、梅津真人、今井佑磨、藤崎洋平、Valerie Swee Ting Goh,佐々木直美、有吉健太郎、三浦富智、山田裕、吉田光明イノシシにおける二動原体染色体の検量線作成P-51 P-52石庭寛子、アンダーソンドノヴァン、藤崎洋平、奥田圭、吉田光明、稲葉俊哉、長町安希子、難波謙二、三浦富智………………………… . . .福島第一原子力発電所事故による環境影響を解明するための野外と照射実験の比較研究渡辺嘉人、Vasyl Yoschenko、府馬正一、丸山耕一、山田裕…太田川の水生昆虫における放射性セシウムの生物利用性と放射性セシウム粒子石井弓美子、趙在翼、林誠二、三浦輝、津旨大輔、和田敏裕、金指努、離波謙二、寺本航、早乙女忠弘、斎藤梨絵 . P-53 P-54 Multi-sources images time-series for landscape dynamics analysis in rural areas after Fukushima accident Lissak Candide, Onda Yuichi, Kato Hiroaki, Preux Thibaut, Dufour Simon Contribution of K transporters to Cs uptake and accumulation in rice P-55 P-56 Nathalie Leonhardt, Satomi Kanno, Shigeto Fujimura, Takuro Shinano, Jun Furukawa
P-57 Determination of local ecological factors on soil-to-plant transfers in Fukushima forest ecosystems Vasyl Yoschenko, Alexander Brandl, Jian Zhang . P-58 Effects of radionuclide exposure on microbiome of wild boar Jim Beasley, Kenji Nanba, Sarah Chinn, Kakeru Ambai, Diana Lafferty . P-59 Determination of radiation dose to Large Japanese Field Mice in the vicinity of Fukushima Daiichi Nuclear Power Plant Mariah Davis, Thomas Johnson, Tsugiko Takase, Yuki Odagiri, Yusuke Mitsuyasu, Hisashi Shinoda, Toshitaka Oka, Hiroko Ishiniwa P-60 P-61 P-62 P-63 P-64 P-65 P-66 P-67 P-68 P-69 P-70 P-71 P-72 P-73 P-74 P-75 P-76河川環境における魚の骨を用いた福島第一原子力発電所事故由来の放射性ストロンチウム汚染の評価苅部基一、藤野凌太郎、永見拓夢、田副博文P-77 P-78福島県浪江町で捕獲されたネコの生殖器中放射性セシウムの測定と分析藤嶋洋平、木野康志、小野拓実、有吉健太郎、吉田光明、葛西宏介、三浦宮智、中田章…高線量地域に楼息するアライグマ骨および軟骨を用いた放射性物質の取り込みと排泄における加齢要因の検計清水良央、高橋温、三浦富智、篠田壽…福島原発事故に被災した野生ニホンザル生体試料を用いた包括的放射線影響解析鈴木正敏、遠藤暁、松谷祐輝、木野康志、小野拓実、岡壽崇、高橋温、清水良央、篠田壽、三浦富智、有吉健太郎、吉田光明、福本学
Estimation of biomass and stocks biologically mobility radionuclides using methods of processing aboveground and remote sensing data for radioactively contaminated forests in Ukraine D. Holiaka, H. Kato, V. Yoschenko, Y. Onda, Y. Igarashi, K. Nanba, P. Dyachuk, R. Zahorodnuk ..............................100陸生無脊椎動物における放射性セシウムの移行経路の解明田中草太、柿沼徳垂、足達太郎、安藤麻里子、小嵐淳茎頂部にCsを蓄積しないVigna属耐塩性野生種の探索野田祐作、古川純富岡町におけるイノシシ中の放射性物質濃度評価折田真紀子、高村昇、崔力萌、平良文亨、山田裕美子、塚田祥文.福島県の内水面漁業復興に向けた外来種チャネルキャットフィッシュの放射能汚染状況の解明と駅除手法の確立高木淳一、和田敏裕、三田村啓理…太田川上流域における魚類への放射性セシウム移行特性の解明寺本航、和田敏裕、石井弓美子、林誠二、離波謙二… DNA analyses to estimate life-time dose from radiation exposures estimation of life-time doses to wild boar using dicentric chromosome analysis Donovan Anderson, Tomisato Miura, Yohei Fujishima, Kei Okuda, Kenji Nanba, Thomas Hinton, Hiroko Ishiniwa . Muse細胞を用いた放射線障害に対する治療法の開発藤嶋洋平、橋本拓磨、漆原佑介、李根、出澤真理、細井義夫…野生ニホンザルの体内放射性セシウム動態に関する研究漆原佑介、鈴木正敏、桑原義和、木野康志、関根勉、篠田壽、青野辰雄、福本学、細井義夫...........................108避難指示区域及びその周辺地域を包括した福島県内におけるイノシシの個体群構造の究明斎藤梨絵、今藤夏子、根本唯、熊田礼子、玉置雅紀樹木年輪に記録された原発事故由来C-14の分布
帰還困難地域で人間活動が減少した環境下における渓流魚類の集団遺伝学的動態の評価津田吉晃、赤池真樹、湯本景村、山川宇宙、Faulks Leanne Kay、兼子伸吾、和田敏裕.分泌性因子を介した放射線影響の発現機構菓子野元郎、有吉健太郎、熊谷純… P-79 P-80減数分裂に着目した継世代影響評価系の開発

計測・分析分野
P-84 Precise and accurate measurement of uranium isotope ratios at nanogram level using multi Daly collectors of MC-ICP-MS P-85 P-86 P-87 P-88 P-89 P-90 P-91 P-92 P-93 P-94 P-95 P-96染色体凝縮阻害剤を用いた新規細胞遺伝学的線量評価法の確立...........................................................136阿部悠、吉田光明筑波実験植物園におけるバイオエアロゾルとセシウム濃度の時系列データ解析石塚正秀、田中邦明、宮本えりか、羽田野祐子、保坂健太郎、北和之、牧輝也、五十嵐康人………………………137高濃度放射性セシウム含有微粒子（Cesium-rich microparticle,CsMP）の多角的精密分析に基づく炉内の情報と環境影響P-97 P-98池原意平、諸岡和也、末武瑞樹、小宮樹、栗原英太郎、武原政人、高見龍、山崎信哉、宇都宮聡……………138カルサイト及びアラゴナイト中のストロンチウム局所構造解析P-99
P-100大気中放射性核種測定器校正のための曝露実験岩岡和輝、玉熊佑紀、細田正洋、赤田尚史、床次眞司2ノズルタイプ3 Dブリンタを利用したガンマ線測定用基準線源の開発P-101 .................................................142育藤敬、小池裕也、田副博文. P-102高精細なMesh-type人体ファントムとPHITS計算を用いた原子力災害に伴う被ぼく推定評価法の構築阪間珍、佐瀬卓也、赤田尚史…東日本大震災を経験していない児童等に対する放射線・震災教育の調査および最適な教育コンテンツの模索P-103佐瀬卓也、阪間稔、赤田尚史… P-104 福島第一原発事故後の環境に棲息するアライグマの歯におけるESR測定を妨害する因子の特定とトラプルシューティング高橋温、岡壽崇、小荒井一真、篠田壽. P-105桜島の火山活動とラドン及び子孫核種濃度の解析種ロ健太、細田正洋、床次眞司、秋葉澄伯…水中ラドン濃度測定による海底湧水探索手法の検討P-106古川雅英、城間吉貴、細田正洋、赤田尚史、真田哲也、仲宗根峻也、伊志嶺聡伸、中村夏織、床次眞司..147福島第一原子力発電所近傍の環境試料の核種分析による沈着状況の解明P-107箕輪はるか、吉川英樹、田副博文.環境中ラドンによる放射線施設監視モニタの感度確認P-108安岡由美、床次眞司、細田正洋、飯本武志、向高弘… P-109  Cs保持に関わる環境試料の前処理・分析手法の確立一ToF-SIMSを用いたCs同位体比測定の検討－田籠久也、川村秀久、草野桂一、土肥輝美… P-110　放射性セシウムの移動媒体についての鉱物学的研究...........................................................................................................................151萩原大樹、小西博巳. P-111　Cs用DGTデバイスを用いた放射性Csの環境動態評価
P-112 多面的な分光学的手法による多価金属イオンの収着状態評価佐々木隆之、小林大志、藤原健壮、土肥輝美、飯島和毅… P-136  Method development and radioactivity analysis of strontium-90 in environmental samples by ICP-MS Chen Fei, Zhang Zhen, Jiao Ling, Tazoe Hirofumi, Yang Guosheng
存在形態分野
P-113　放射性金属イオンを含む錯体の安定性　～量子化学シミュレーションによる評価～高瀬つぎ子、和田山晃世、中村俊輔、大山大P-114   Studies on nickel(II) and cobalt(III) complexes of an isomeric polyazamacrocyclic chelator and its N-pendent derivative for the application in radioactive waste decontamination Tapashi G. Roy, Saroj K.S. Hazari, Benu K. Dey, Debashis Palit, Lucky Dey, Zinnat A. Begum, Ismail M.M. Rahman P-115 Studies on the distribution and migration characteristics of actinides in typical karst environment Hai Wang, Jian Zheng, Detao Xiao, Ming Liu, Xiangyang Luo . P-116 ベイジアン移流拡散方程式による大気中の放射性物質拡散挙動の長期予測内山祐介、羽田野祐子..............................................158 P-117　２フィルター法を用いたラドン族遺度測定器の原子力災害における空気中放射性物質濃度測定への応用利用五十嵐悠、飯本武志、細田正洋P-118 ラドン・トロン拡散型測定器に使用される子孫核種除去フィルタのトロン浸透率大森康孝、玉熊佑紀、鈴木崇仁、Eka Djatnika Nugraha、Miki Arian Saputra、細田正洋、床次眞司…………160 P-119 福島原発事故により放出された放射性微粒子中に含まれる雛輝発性核種の分析五十嵐淳哉、鄭建、張子見、二宮和彦、佐藤志彦、福田美保、倪有意、青野辰雄、篠原厚

Oral Presentation
口頭発表
O-1
Impact of competing ions in aqueous matrix towards strontium
selectivity in the designated solid-phase extraction systems:

Ismail M.M. Rahman* ¹ M. Ferdous Alam ² , Yoshiaki Furusho ³ , Kenji Nanba ² ¹ Institute of Environmental Radioactivity, Fukushima University, Japan ² Graduate School of Symbiotic System Science and Technology, Fukushima University, Japan ³ GL Sciences, Inc., Japan *Corresponding author: immrahman@ipc.fukushima-u.ac.jp The intrusion of radiostrontium (r-Sr) isotopes in the ecosystem occur from nuclear technology-related activities. The 90Sr, the longest-lived r-Sr isotope (to.5, 28.8 years), shows higher mobility in the ecosystem compared to many other radionuclides. The reliability in exposure prediction due to a radionuclide depends on the analytical accuracy. Analytical protocols for total r-Sr determination include multiple pre-processing steps for the separation of strontium from the coexisting or competing matrix components. However, limited selectivity in each of such steps generates a prolonged protocol, which can be curtailed by taking advantage of more selective separation agents. The solid-phase extraction (SPE) approach combines a selectivity in extraction and simplicity in those protocols. In the current work, three different SPE systems designated for selective Sr-separation, namely AnaLig Sr-01, Eichrom Sr-resin, and Eichrom DGA resin, were used, and the corresponding performances were compared for the Sr-separation from aqueous matrices in the presence of competing ions. Keywords : solid-phase extraction, strontium, selective separation
0-2
Application of thermal ionization mass spectrometry for
90Sr analysis
Norbert Kavasi 1 , Sarata Kumar Sahoo* 1 , Tatsuo Aono 1 1 National Institutes for Quantum and Radiological Science and Technology (QST) *Corresponding author: sahoo.sarata@qst.go.jp The 90Sr (T1/2 = 28.8 y) is a pure beta emitter radioisotope, produced by the fission of U and Pu isotopes. Low level (some Bq kg -1 or mBq kg -1) 90Sr contamination exists in different environmental matrices as a result of nuclear weapon tests and nuclear accidents. The Sr element shows bio-chemically similarity to calcium, therefore the 90Sr isotope can incorporate into the human bone structure causing long-term radiation dose. Considering the public health and natural radiation protection, precise and accurate determination of 90Sr in various environmental, biological and radioactive waste samples is important. Radiometric methods have been mainly used for 90Sr analysis, but owing to significant developments on sample introduction, detector and interference removal techniques, many successful 90Sr determinations have been reported using mass spectrometry instruments. The main advantages of the mass spectrometry method over the radiometric are the shorter analysis time, higher sample throughput and smaller sample intake. In this work, a new 90Sr analysis method using Thermal Ionization Mass Spectrometry (TIMS) equipped with a Daly ion-counting system will be introduced. Detection of 0.2 fg (1 mBq) 90Sr was demonstrated with an excellent abundance sensitivity for the 90Sr/88Sr isotope ratio (2.1 × 10-10). For method validation, certified reference material (wild berry - IRMM-426, 90Sr= 124 ± 24 Bq kg-1) and standard reference material (freshwater lake sediment - NIST- 4354, 90Sr= 512 ± 118 Bq kg-1) were analysed. This new method was also evaluated, - for the first time in the history of mass-spectrometry -, in a worldwide open proficiency test (IAEA-TEL 2017-3). The 90Sr was determined in tap water and milk powder samples and 'accepted' status was gained for both accuracy (relative bias of 4.2 % and 2.1 %, respectively) and precision (relative uncertainty of 3.1 % and 5.7 %, respectively). Keywords : 90Sr, mass spectrometry, TIMS
O-3

Sharayu Kasar ¹ , Sarata Kumar Sahoo* ¹ , Tatsuo Aono ¹ National Institutes for Quantum and Radiological Sciences and Technology (QST) *Corresponding author: sahoo.sarata@qst.go.jp Fukushima Daiichi Nuclear Power Station (FDNPS) accident has resulted radioactive contamination due to deposition of mainly radiocesium as well as many long-lived radionuclides surrounding the area. Depending upon environmental conditions, radionuclides can be mobilized in aquatic systems. The investigation of sorption-desorption behavior of any radionuclides in soil-water system is a key issue in assessing the movement of radionuclides in contaminated areas. It is commonly expressed as a distribution coefficient ( Kd value) and significantly influenced by radionuclide distribution between water and soil. Cs radionuclides in contact with living beings replace K and Na, whereas Sr radionuclides take the place of Ca. Uranium is ubiquitously distributed in earth' s crust whereas enriched 235U is mainly used as nuclear fuel. Therefore, study of distribution coefficients of Cs, Sr and U nuclides in Fukushima environment is of major concern from migration and radiological safety points of view. Batch sorption-desorption experiments were carried out in Fukushima contaminated soils from Namie and Okuma towns using laboratory batch method in equilibrium with ground water. Sorption coefficient, Kd(S) of Cs and Sr was found to be in the range of 65 to 2100 and 15 to 130 L/kg respectively. Kd(S) - U values varied from 30-36000 L/kg i.e. three orders of magnitude difference. High values of Kd(S) reflect more sorption capacity of soil for U and Cs than Sr. Values of desorption coefficient, Kd(D) - Cs varied from 75 to 2500 L/kg and Kd(D) - Sr was from 10 to 120 L/kg. The higher Kd values for Cs observed in the desorption process than in the sorption process showed irreversibility of Cs sorption in soil. Effect of cation exchange capacity, clay content and soil mineralogy on Cs, Sr and U sorption has also been studied in Fukushima environment. Keywords : distribution coefficient, Cs, Sr, U, Fukushima contaminated soils
O-4
Radiation dose rate of Japanese cedar and plants collected from
Okuma applying ERICA tool
Nguyen Phuong Thoa ¹ , Shishido Koya ¹ , Hajime Ohira ¹² , Shingo Kaneko ¹ , Hirofumi Tsukada* ³ 1 Faculty of Symbiotic Systems Science, Fukushima University ²  Parks and Recreation Foundation ³ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: hirot@ipc.fukushima-u.ac.jp Wild animals and plants living in evacuation zones have been received the additional ionizing radiations of both internal and external radiation doses after the 2011 FDNPS accident. Morphological abnormalities of pine and fir trees near the FDNPP were reported. It is necessary to quantify internal and external radiation doses of trees and plants for evaluating the dose-effect relationships. In the present study internal and external dose rates of Japanese cedar and plants collected in three sites (S1, S2, S3) in Okuma were estimated applying the ERICA tool. The activity concentrations of 134Cs and 137Cs in soils, cedar trunk and plants were used for the dose calculation. The total dose rate of cedar in S1 (9.8 ± 2.0 µGy h ⋅ ¹) were within the derived consideration reference levels (DCRLs) reported as 4 - 40 µGy h·¹ for pine trees by ICRP 108. The estimated value for plants was the highest in S1 (11.6 ± 2.2 µGy h·1), much smaller than the reported DCRLs for grasses and herbs (40 - 400 μGy h ⋅ 1). Ratios of internal to external dose rates to cedar in S1 and S2 were 0.04 ± 0.02 (n=3) and 0.24 ± 0.20 (n=4), respectively, and much higher than that of S3 (0.004 ± 0.002, n=3). The trunk diameters in S1 and S2 are 3 times higher than those in S3, showing positive correlation with canopy area. It may attribute the radiocaesium deposition in trees of S1 and S2 is higher than that in S3. The ratio for plants in S1 was 0.009 ± 0.005 (n=6), which was smaller than in S2 (0.03 ± 0.02; n=10) and S3 (0.12 ± 0.11; n=6). The reason could be plant species accumulating more radiocaesium found mostly in S3. Radiocaesium in soils was major contribution to total dose rates to cedar and plants in Okuma. Keywords : external and internal dose rates, ERICA tool, cedar, plants
O-5
potential importance in forest ecosystems
Kentaro Hosaka* ¹ , Kohei Yamamoto ² , Taiga Kasuya ³ , Kyung-Ok Nam ¹ , Hiroko Ishiniwa ' ¹ Department of Botany, National Museum of Nature and Science ² Tochigi Prefectural Museum ³ Department of Biology, Keio University 4 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: khosaka@kahaku.go.jp Fungi show the highest diversity and biomass in terrestrial ecosystems.  Furthermore, fungi, especially mushrooms, are known to accumulate more radiocesium than many other terrestrial organisms.  After the Chernobyl and Fukushima accidents, several studies demonstrated that ectomycorrhizal mushrooms (mushrooms having mutualistic association with trees) tend to effectively accumulate radiocesium.  However, none of those studies have attempted to document the concentrations of radiocesium in truffle-like fungi, which mostly are ectomycorrhizal.  This project aimed to sample diversity of truffle-like fungi from forest environment and from feces of mycophagous animals to access their importance in radiocesium dynamics in forest ecosystems.  Currently, the concentrations of radiocesium in diversity of truffle-like fungi collected from Fukushima Prefecture and other areas (e.g., Tsukuba city in Ibaraki Prefecture) are being compared. Keywords : fungi, hypogeous mushrooms, mycophagous animals, radiocesium, truffles
地下生菌（トリュフ類）と小動物を介した森林内の放射性セシウム
の動態把握
保坂健太郎* ¹、山本航平²、糟谷大河²、南京沃¹、石庭寛子* 1国立科学博物館物研究部²栃木県立博物館学芸部自然課³慶應義塾大学生物学教室‘福島大学環境放射能研究所*責任著者: khosaka@kahaku.go.jp陸上生態系において菌類は種多様性が最も高く、バイオマスも最大である可能性が指摘されている。さらに菌類、特にきのこ類は放射性物質（セシウム）の蓄積特性が、他の生物に比べ高いという観察結果も示されている。きのこ類のうちで特に高い放射能濃度を示すものとしては、チェルノプイリ原発事故および福島第一原発事故後の研究により、樹木と共生する菌根性きのこが挙げられている。しかし、大部分が菌根性である地下生菌（いわゆるトリュフ類）については、放射性物質の蓄積特性が全くわかっていない。本研究では多様なトリュフ類を森林およびげっ歯類の葉中より採集・同定し、種ごとの放射性物質の蓄積特性を明らかにすることを目的とした。今のところ福島県各地からのトリュフ類が採集されており、他の地域（茨城県つくば市など）のサンプルにおける放射性セシウム濃度の比較を試みている段階である。キーワード：菌食動物、菌類、地下生菌、トリュフ、放射性セシウム
O-6
Transfer of cesium 137 from riparian forest to a headwater stream
ecosystem in Fukushima
Tsutomu Kanasashi* ¹ , Yoshiko Ayabe ² , Chisato Takenaka ² , Naoki Hijii ² ' Institute of Environmental Radioactivity at Fukushima University ² Graduate School of Bioagricultural Sciences, Nagoya University *Corresponding author: t.kanasashi@ier.fukushima-u.ac.jp Leaf-litter input from riparian forest to a headwater stream is important allochthonous nutrient source for a headwater stream ecosystem. We elucidated 137Cs transfer from riparian forest to a headwater stream ecosystem through input of leaves contaminated by radionuclides due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) Accident. In riparian zone of Kawamata-machi, Fukushima, living leaves of konara oak ( Quercus serrata ) were collected from crowns in 2013 and fresh-senescent leaves of that, which shed from crowns of the tree, were collected from forest floor in November 2013. Senescent leaves, which include konara oak' s ones and were accumulated in a headwater stream of the site, were also collected in November 2012, March 2013 and May 2013. The comparison of 137Cs concentrations showed that living leaves of konara contained higher 137Cs than the fresh-senescent ones in the forest floor, and then, the fresh-senescent ones in the forest floor contained higher one than those in the headwater stream. Therefore, we consider that 137Cs in the living leaves was released to forest floor and headwater stream while they become senescent and accumulate in the locations. Especially, in the headwater stream, water-soluble 137Cs is suggested to be released from the leaves immediately after they accumulate in there because 137Cs concentration showed little temporal variation from November to May. 137Cs concentrations in aquatic insects with three feeding groups (shredder, predator and others) showed temporal change, but 137Cs concentrations of them were similar or lower than those in the leaves accumulated in the headwater stream. Keywords : litter patch, feeding group, konara oak
渓畔林から渓流生態系へのセシウム137の移行
金指努* '、綾部慈子'、竹中千里'、肘井直樹' ¹福島大学環境放射能研究所²名古屋大学大学院生命農学研究科*責任著者: t.kanasashi@ier.fukushima-u.ac.jp福島第一原子力発電所事故に起因する、森林から渓流生態系への落葉を介した放射性セシウムの移動の実態を明らかにするために、福島県川俣町の小渓流において、渓畔域に優占して分布するコナラ（Quercus serrata）の生葉、林床の枯死・脱落葉（落葉）及び渓流に堆積している落葉の137Cs濃度変化を明らかにした。コナラの葉は、生葉から枯死・脱落し、渓流に堆積する過程で、137Cs濃度が減少した。2012年の落葉期に林床に落下したコナラ葉と、渓流に堆積したコナラ落葉の137Cs濃度を比較すると、渓流のコナラ落葉の方が低くなった。渓流に堆積後、落葉の137Cs濃度に有意な時間変化が認められなかったことから、渓流に堆積後、水溶性の137Csが比較的速やかに減少したことが要因のひとつと考える。渓流に堆積している落葉溜まりから採取された水生昆虫に含まれる137Cs濃度は、落葉と同程度か低くなり、本研究では、落葉から水生昆虫への137Csの濃縮は認められなかった。キーワード：リターバッチ、摂食機能群、コナラ
O-7
Establishment of a simplified approach to detect oxidative stress using 8-OHdG positive testicular cell measurements in the large Japanese field mice Masanori Tamaoki* ¹ , Manabu Onuma ¹ ² , Hiroko Ishiniwa ² ¹ Fukushima Branch, National Institute for Environmental Studies ² Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies ³ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: mtamaoki@nies.go.jp The generation of 8-OHdG (8-hydroxy-2' -deoxyguanosine), which is produced from the reaction between hydroxide with guanine, is a major method to detect oxidative stress. Since oxidative stress is also induced by radiation exposure, large Japanese field mouse ( Apodemus speciosus ) were collected from multiple areas within the difficult-to-return zone in Fukushima to evaluate radiation effects on reproductive organs, such as testicular tissues, have a high sensitivity to radiation exposure and have a biological importance, thus we investigated possible production of 8-OHdG in these organs. However, specialized knowledge and techniques are required to effectively evaluate testicular tissues, such as the analysis of discriminating between spermatogenesis stage which proficiency requires time and effort. Therefore, the aim of this study was to establish a simplified measuring method of testicular 8-OHdG positive cells that can be performed by inexperienced persons while maintaining a certain degree of accuracy. Using testicular tissues of large Japanese field mice captured from the difficult-to-return zone, 100 testicular cells were selected without bias from each spermatogenesis stage to be evaluated using the conventional method and 100 testicular cells were randomly selected to be evaluated using the simplified method, then the number of 8-OHdG positive cells was counted for each. In consequence, the number of positive cells had a positive correlation between the conventional and simplified methods (Kendall' s tau=0.672, z=8.781, p<0.01) indicating that the simplified measurement method was effective. In addition, we will introduce results of the comparison of oxidative stress responses between difficult-to-return and control areas. Keywords : oxidative stress, 8-OHdG, radiation, large Japanese field mouse, Apodemus speciosus
アカネズミ精巣における8-OHdG陽性細胞の簡易測定法
玉置雅紀* ¹、大沼学²、石庭寛子³ 1国立環境研究所福島支部²国立環境研究所生物・生態系環境研究センター ³福島大学環境放射能研究所*責任著者: mtamaoki@nies.go.jp DNAを構成する塩基の一つであるグアニンにOH-が付加されることで生成される8-OHdGは酸化ストレスを評価する主要な方法である。酸化ストレスは放射線ばく露によっても引き起こされることから、著者らは福島県の帰還困難区域においてアカネズミを捕獲し、放射線感受性が高く生物学的にも重要な生殖組織について8-OHdGを酸化ストレスマーカーとして放射線影響の評価を行ってきた。しかし、精巣組織の評価には精子形成ステージを判別するなど専門的な知識と技術が要求され、その習熟には多大な時間と労力が必要になる。そこで、非熟練者であってもある程度の精度を保って8-OHdGによる酸化ストレス測定を行うことが可能な簡易測定法について検討した。本研究では従来法として帰還困難区域において捕獲されたアカネズミ精巣より精子形成各ステージから偏りなく100細胞を選出、また、簡易法としてランダムに100細胞を選出し、8-OHdG陽性細胞数を計測した。その結果、従来法と簡易法の陽性細胞数は正の相関が見られ(Kendall' s τ =0.672, z=8.781, p<0.01)、簡易潤定法が有効であることが明らかになった。加えて本発表では、帰還困難区域と対照区域において酸化ストレス応答の比較を行った結果を紹介する。キーワード：酸化ストレス、8-OHdG、放射線、アカネズミ、Apodemus speciosu
O-8
Possibility of transition of radio-cesium between aerosol and
vegetation
Kita Kazuyuki* ¹ , Kanoh Mizuki ¹ , Niiya Watamu ² , Kimura Mao ¹ , Furukawa Jun ² , Hatano Yuko ² , Igarashi Yasuhito 1,3 1 Graduate school of Science and Engineering, Ibaraki University ² Center for Research in Isotopes and Environmental Dynamics, Tsukuba University ³ Institute for Integrated Radiation and Nuclear Science, Kyoto University *Corresponding author: kazuyuki.kita.iu@vc.ibaraki.ac.jp Radio-cesium emitted by the TEPCO FDNPP accident has been deposited on soil and vegetation after transpiration in the atmosphere. Atmospheric concentration of its radioactivity showed seasonal maximum in summer near forest areas, some studies showed it was caused by re-emission of radio-cesium by release of fungal spores and other bio-aerosols. We found that a significant part of radio-cesium in summer aerosol could be water-soluble, suggesting the possibility of circulation of radio-cesium between the atmosphere and the vegetation. To make clear this possibility, we performed the following experiments: 1) Aerosol samples collected in Namie site, Fukushima, throughout the year of 2018, were extracted by pure water. And rice was cultivated in the extracted solution to measure the fraction of water soluble and of absorbable by plants in the atmospheric radio cesium. 2) Some plants were cultivated in A:surface soil, B: soil under the surface soil, C:red ball cray soil at Namie sites, Fukushima, between May and September, 2019, to estimate radio-cesium absorbed by the plants from its dry and wet deposition. The results of these experiments will be presented. Keywords : atmospheric radio-cesium, vegetation, fungi, precipitation, atmosphere-vegetation circulation大気エアロゾルと植物・菌類間での放射性セシウム移行可能性の研究北和之* ¹、加納瑞季¹、二井矢航²、木村茉央¹、古川純²、羽田野祐子²、五十嵐康人¹³ ¹茨城大学理工学研究科²筑波大学アイソトープ環境動態研究センター ²京都大学複合原子力科学研究所*責任著者：kazuyuki.kita.iu@vc.ibaraki.ac.jp東京電力福島第一原発事故により放出され沈着した放射性セシウムは、一部が再飛散により大気中に放出され、拡散・移行している。森林近傍では大気放射性セシウムが夏季に増加する季節変化を示し、菌類胞子などにより植生から放出されたと思われる。これまでの実験により、この時期の大気粒子サンプル中の放射性セシウムの多くが水中に脱離することが分かった。このことから、菌類による放出、大気からの乾性・湿性沈着とその植生による吸収により、放射性セシウムが大気一植生間を循環している可能性が考えられる。そこで、以下の２つの実験を行った。 １）福島県浪江町において2018年の１年間を通しハイポリュームエアサンプラーで捕集した大気粒子試料から、純水抽出した溶液によりイネを栽培し、大気粒子から水への移行割合および植物移行の割合、およびその季節変化を調べる。 ２）福島県浪江町の観測サイトにおいて、A:表土(0-5cm)、B:心土(5-20cm)、C:園芸土(参照用)の3種類の土で、幾つかの植物を５～９月にかけ栽培し、吸収された放射性セシウムを測定する。これらの結果について、報告会にて発表を行う。キーワード：大気放射性セシウム、植物、菌類、降水、大気-植生間循環
O-9
Accumulation and redistribution of 137Cs on floodplains along the
Abukuma River
Yoshifumi Wakiyama* ¹ , Alexei Konoplev ¹ , Valentin Golosov ² , Maxim Ivanov ² , Mikhail Komissarov ³ 1 Institute of Environmental Radioactivity, Fukushima University ²  Faculty of Geography, M.V. Lomonosov Moscow State University ³  Ufa Institute of Biology UFRC, Russian Academy of Science *Corresponding author: wakiyama@ipc.fukushima-u.ac.jp A portion of sediment-borne 137Cs in river water accumulates on floodplains during high-flow events and becomes a source of secondary contaminations in subsequent events. This study aims to elucidate processes of 137Cs accumulation / redistribution on floodplains and presents the 137Cs inventory and depth distribution in deposited sediments. The sediment cores were taken in 2018 and 2019 at six floodplain cross-sections, located along the Abukuma River in Nihonmatsu (NIH), Kuroiwa in Fukushima (KUR), Fushiguro in Date (FUS), Marumori (MAR), Kakuda (KAK), and river mouth section in Iwanuma (Mouth). The mean 137Cs inventory obtained by sampling campaigns in October 2018 at NIH, KUR, FUS, MAR, KAK, and Mouth were 150 kBq m ² (n = 2), 600 kBq m ² (n = 3), 490 kBq m ² (n = 2), 270 kBq m ⋅² (n = 2), 90 kBq m ⋅² (n = 2), and 40 kBq m ⋅² (n = 1), respectively. These values were 1.2-9.1 times higher than those estimated by 6th airborne survey at each point, suggesting secondary accumulation of 137Cs. The 137Cs inventory and maximum 137Cs concentrations in sediment depth profile tended to be high at the sampling points, located on the highest floodplain level above the river channel within each floodplain cross-section. The mean 137Cs inventory obtained by sampling campaigns in October and November 2019 at NIH, KUR, FUS, MAR, KAK, and Mouth were 180 kBq m·² (n = 2), 540 kBq m·² (n =2 ), 410 kBq m·² (n = 1), 120 kBq m·² (n = 2), 420 kBq m·² (n = 3), and 46 kBq m·² (n = 1), respectively. Although 137Cs inventory on the floodplains are not so different, depth distributions of 137Cs in the deposited sediment changed from those of 2018. These results suggest that an extreme flood triggered by Typhoon Hagibis in middle of October 2019 resulted in a substantial redistribution of 137Cs at Abukuma fluvial system. Keywords : 137 Cs, Abukuma River, floodplains, sediment dynamics
阿武隈川の高水敷における137Csの蓄積と再移動
脇山義史* ¹、Alexei Konoplev ¹、Valentin Golosov ²、Maxim Ivanov ²、Mikhail Komissarov ³ ¹福島大学環境放射能学研究所²モスクワ州立大学地理学部³ロシア科学アカデミーウファ生物学研究所*責任著者: wakiyama@ipc.fukushima-u.ac.jp出水イベント時には、河川を通じて土砂とともに137Csが輸送され、その一部は高水敷に蓄積し、後続の出水イベント時の二次汚染源となる。本研究では、高水敷における137Cs著預・再移動プロセスを明らかにするため、阿武隈川の高水敷6地点において137Csのインペントリーおよび深度分布を調べた。二本松市安達ケ原（NIH）、福島市黒岩(KUR)、伊達市伏黒(FUS)、丸森町舘矢間(MAR)、角田市枝野(KAK)、岩沼市河口部(Mouth)の高水敷において、堆髄物の柱状コアを採取し、137Cs濃度の分析を行った。2018年10月の採取・分析の結果、各高水敷における平均137Csインベントリーは、NIHで150 kBq m ⁄² (n = 2)、KURで600 kBq m ⁄² (n = 3)、FUSで490 kBq m ⁄² (n = 2)、MARで270 kBq m ² (n = 2)、KAKで190 kBq m ² (n = 2)、Mouthで40 kBq m ² (n = 1)であった。これらの値は第6次航空機モニタリングに基づく137Csインベントリーに比べて、1.2 ～ 9.1倍高い価であり、二次的に137Csが蓄積したことが示唆された。複数点のコアサンプリングを行った高水敷では、河川から遠い地点ほど、137Csインベントリーが高く、堆積物の137Cs濃度の最大値が大きくなる傾向が見られた。2019年10・11月の採取・分析の結果、平均137Csインベントリーは、NIHで180 kBq m 2 (n = 2)、KURで540 kBq m 2 (n = 2)、FUSで410 kBq m 2 (n = 1)、 MARで120 kBq m -2 (n = 2)、KAKで420 kBq m -2 (n = 3)、Mouthで46 kBq m -2 (n = 1)であった。2018年に比べて、 137Csインベントリーには大きな違いはなかったが、堆積物中の137Cs深度分布に大きな変化が見られた。以上の結果から、2019年の台風19号にともなう洪水によって多量の137Csが再移動したと考えられる。キーワード：137Cs、阿武隈川、高水敷、土砂動態
O-10
Ecological half-life of radiocesium in surficial bottom sediments of
ponds in Fukushima based on in-situ measurements with plastic
scintillation fibers
Estiner W. Katengeza* ¹ , Yukihisa Sanada ² , Kazuya Yoshimura ² , Kotaro Ochi ² , Takeshi Iimoto ¹ . ¹ Environment Systems, The University of Tokyo. ² Fukushima environmental Safety Center, Japan Atomic Energy Agency. *Corresponding author: 6922884407@edu.k.u-tokyo.ac.jp Fukushima prefecture hosts over 3500 ponds onto some of which radioactive fallout from the Fukushima Daiichi Nuclear Power Plant accident of 2011 was deposited. Because of their important role in supporting people' s livelihoods through irrigation agricultural, long-lived radionuclides such as 137Cs remain a radiological concern in the long-term. Radiocesium strongly adsorbs to sediments, and therefore its presence in aquatic environments is predominantly in bottom sediments and movement is mainly by mechanical processes. Because of these mechanical processes, the rate of temporal change of radiocesium concentration in bottom sediments is governed not only by its physical decay but also by various ecological processes. In this study, the decreasing trend of radiocesium concentration, due to ecological processes, over wide pond areas in surface sediments (up to 10 cm depth) was investigated using plastic scintillation fibers (PSF) and was quantified by the ecological half-life.  PSF measurements were made between 2013 and 2019 and their conversion factors were obtained by comparison with concentration of sediment cores collected from coinciding positions within the same ponds and measured by a germanium detector.  The ecological half-life among the ponds ranged from 3.4 ± 0.4 years to 28 ± 31 years. A forest-catchment pond exhibited the longest ecological half-life and may indicate the catchment-derived radiocesium input as was partly evident in the spatial- temporal patterns of radiocesium concentration at this pond' s inlet. This study demonstrates the importance of wide area monitoring techniques in obtaining an overview of the temporal behavior of radiocesium while accounting for spatial heterogeneities and is a first attempt to quantify such changes over wide pond areas. Keywords : plastic scintillation fiber, in-situ radioactivity measurement, radiocesium, ecological half-life.
O-11
Determination of labile 137Cs fraction in zooplankton associated
with model analysis of bioavailable cesium transfer in marine food
chain
Yutaka Tateda*  ¹ , Jun Nishikawa ² , Tatsuo Aono ³ , Shinnosuke Yamazaki ³ , Michio Aoyama ¹ , Yasunori Hamajima ⁵ , Daisuke Tsumune ¹ , Takuya Kobayashi ¹ ,Takashi Ishimaru ° , Jota Kanda ° , Yukari Ito ° , Minoru Kitamura ² 1 Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry ²  Department of Marine Biology, Tokai University ³ National Institutes for Quantum and Radiological Science and Technology 4 Center for Research in Isotope and Environmental Dynamics, University of Tsukuba, 5 Institute of Nature and Environmental Technology, Kanazawa University 6 School of Marine Life Science, National Tokyo University of Marine and Technology 7 Japan Agency of Marine Earth Science and Technology *Corresponding author: tateda@criepi.denken.or.jp The concentration ratio (CR) for radiocesium in zooplankton was 15 before the Fukushima accident. Since the 137Cs levels in seawater was rapidly decreased and the turnover in zooplankton was fast enough, the CR was expected to be decreased. However, the reported CR in 2015 was still higher than the accident before. The radiocesium levels in organisms belong to planktonic food chain were decreased as expected, thus the comparatively higher 137Cs levels may contain refractory fraction. The analyzed level in H2O2 extractable fraction in zooplankton during 2011-2018, demonstrated that the labile ratios were 0.2 - 0.6. The 137Cs concentration in organisms belonging to planktonic food chain were reconstructed by model analysis using the bioavailable faction derived in this study. Keywords : radiocesium, marine ecosystem, zooplankton, bioavailable fraction
海洋動物プランクトン中易分解性137Cs画分の定量と生物移行モデルによる食物連鎖可給態寄与の解明
立田後* '、西川淳'、青野辰雄'、山崎慎之介'、青山道夫'、浜島靖典'、津旨大輔'、小林卓也'、石丸隆'、神田穣太'、伊藤友加里³、喜多村稔³ ¹（一財）電力中央研究所環境科学研究所²東海大学海洋学部海洋生物学科³量子科学技術研究開発機構放射線医学総合研究所‘筑波大学アイソトープ環境動態研究センター 5金沢大学環日本海域環境研究センター   7海洋研究開発機構*責任著者: tateda@criepi.denken.or.jp福島原発事故以前の海洋動物ブランクトン（PL）における放射性セシウム(Cs)の遗縮比（CR）は15前後であり、水中Cs濃度が低下ト、動物PLにおける速やかなCs代謝から、早い時期に事故前に戻ると期待されていたが、2015年までは事故以前のCRに戻ってはいない。PL食性魚とこれを捕食する魚食性魚では、その濃度が低下したことから、事故後のPL中放射性Csは、食物連鎖を移行しない難分解性両分を含むと仮定した。この仮説の検証を目的として、 2011年以降に東日本北太平洋で採取された試料を過酸化水茶処理して、分解残差中の放射性Cs濃度を定量し、放射性Cs可溶性画分を求めた。その結果、全濃度に対する易分解性画分の比率は0.2 - 0.6であった。易分解性画分を生物可給態とみなして、動的生物移行モデルを用いて、ブランクトン食物連鎖内魚類の濃度推移を再構築した。キーワード：放射性Cs、海洋生態系、プランクトン、生物可給態
O-12
Modeling of radionuclide transport in water systems and
atmosphere:
Recent implementations for Fukushima and Chernobyl regions
Mark Zheleznyak * ¹ ' Institute of Environmental Radioactivity at Fukushima University, Fukushima, Japan *Corresponding author: r702@ipc.fukushima-u.ac.jp After the nuclear accidents the models should be customized for the local conditions to be used as the forecasting tools. The presentation overviews results of the implementation and further extension of the models on the basis of the monitoring data for the regions of Fukushima Prefecture and Chernobyl Exclusion Zone (CEZ). The studies in Ukraine are performed in cooperation with the Ukrainian researchers within the JICA and JST funded project SATREPS. The dynamics of 137Cs concentration in the part of Abukuma river during high floods is modeling by the chain "distributed watershed model – 1D river model” in comparison with the data of the recent IER measurements. The model of 137Cs washing out from watershed was extended by the new submodel of radionuclide transport with sediments. The fate of the radionuclide at Pripyat river floodplain in CEZ in a case of the emergency scenarios – dike break was simulated by the 2-D hydrodynamics – radionuclide transport model. Transport of 90Sr by Pripyat river and the following 90Sr propagation downstream to Kiev area through Dnieper river is simulated by 1D Hydraulic- Radionuclide transport model. The model parameters were calibrated by the processing of the data on the increasing amount of water exchangeable forms of 90Sr measured recently in the samples from the Pripyat floodplain. The Ukrainian and Japanese models of 137Cs atmospheric transport were implemented for the forecasting of the consequences of the forest fires in CEZ. The testing of the developed modeling systems performed during forest wildfires that happen in CEZ 6-8 June 2018. The modeling system predicted the areas of localization of measurable concentrations of 137Cs in air due to this wildfire at western suburb of Kiev, that was confirmed by the measurements of the mobile laboratory. Keywords : 90Sr and 137Cs in rivers, models, Abukuma River, Chernobyl Exclusion Zone, forest fires
O-13

Michio Aoyama * ¹ ¹ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: michio.aoyama@ied.tsukuba.ac.jp The consensus values of total atmospheric release of 137Cs from FNPP1 accident is 15-21 PBq, it for atmospheric deposition of 137Cs on land is 3-6 PBq, it for atmospheric deposition of 137Cs on the North Pacific is 12-15 PBq, it for direct discharge of 137Cs to ocean is 3-6 PBq and it for total inventory of 137Cs in the North Pacific is 15-18 PBq (Aoyama et al., 2019). Regarding with fluxes from domain to domain for several years after the accident, the amount of 137Cs transported by the rivers in the south of Pacific coast of Tohoku region to the ocean might be 40 TBq (Aoyama et al., in revise) which is corresponding to less than 1.3 % of deposited 137Cs on land. In terms of annual flux of 137Cs, it was estimated to be10-12 TBq year-1 in 2011-2012 by 14 rivers around FNPP1 including particulate form and dissolved form (Kitamura et al., 2014) and ca. 0.9 TBq year-1 in Dec. 2016 (Tsumune et al., 2020). In October and November 2019, 137Cs activity concentrations in surface water off Tohoku region were reported to be 10-20 Bq m-3 by governmental monitoring after floods by the Typhoon Hagibis in October 2019. Preliminary results of integration of 137Cs for coastal region off Miyagi, Fukushima and Ibaraki prefectures showed that flux from land to ocean in this region was ca. 0.1 TBq per this typhoon event which might one tenth of annual flux by the rivers. For resuspension, the annual deposition of 137Cs at Okuma during the period from 2014 to 2018 means that 4 TBq year-1 to 10 TBq year- 1 should be amount of resuspension from land to atmosphere and this amount correspond to 0.1 % to 0.3 % of total deposition of 137Cs on land in Japan. The 137Cs activity concentration at 56N canal in 2016-2018 correspond to 137Cs discharge of 0.73 TBq year-1 to 1.0 TBq year-1 from FNPP1 site to open water. As a result of decontamination works, 134 TBq of 137Cs was removed from surface soil until February 2019 which correspond to 4 % of deposited 137Cs on land in Japan. Keywords : 137Cs, flux, river, resuspension, decontamination
電力福島第一原発事故に由来する137Csの物質収支と大気、陸
海洋間の移動の長期挙動
育山道夫* 1
'筑波大学　アイソトープ環境動態研究センター *責任著者: michio.aoyama@ied.tsukuba.ac.jp東電福島第一原発事故からの137Csの大気への放出総量のコンセンサス値は15-21 PBq、陸地への137Csの降下量は3-6 PBq、北太平洋への137Csの降下量は12-15 PBqであり、137Csの海洋への直接漏洩量は3-6 PBq、北太平洋の137Csの総量は15-18 PBqである(Aoyama et al.,2019)。事故後数年間の各領域間の移動量については、東北地方の太平洋沿岸の河川から海洋に輸送された137Csの量は40 TBq（陸上への降下量の1.3％未満）である(Aoyama et al.,改訂中)。137Csの河川での年間輸送量は、FNPP1周辺の14の河川によって粒子態および溶存体を含めて2011- 2012年には年あたり10–12 TBq（Kitamura et al.、2014）と推定された。2016年12月の時点では河川による輸送量は年あたり0.9 TBqであった（Tsumune et al.、2020）。2019年10月の台風へギビスによる洪水後の政府のモニタリングにより、2019年10月と11月東北沿岸の表層海水の137Cs放射能濃度は10 -20 Bq m-3であると報告された。宮城県、福島県および茨城県の沖合に存在する137Csの総量を試算した結果、陸から海へのフラックスはこの台風イベントによりおよそ0.1 TBqであると推定され、河川による年間輸送量の10分の1に相当する可能性がある。陸面からの137Cs再飛散量については、2014年から2018年までの期間中の大熊での137Cs降下量から、年間4 TBqから10 TBq (陸上への降下量の0.1 %から0.3 %に相当)が陸面から大気への再飛散量であると推定された。2016-2018年の福島第一原発から外洋への137Cs漏洩量は年あたり0.73 TBqから1.0 TBqである。除染作業の結果、134 TBq(陸上への降下量の4 %）の137Csが2019年2月まで表土から除去された。キーワード： 137 Cs、フラックス、河川、再飛散、除染
ポスター発表
P-1
Catchment scale estimation of current and future water balance in
the Chernobyl exclusion zone in Ukraine
Yasunori Igarashi * ¹ , Mark Zheleznyak ¹ , Hlib Lisovyi ² , Yoshifumi Wakiyama ¹ , Yuichi Onda ³ , Kenji Nanba ¹ ,
Alexei Konoplev ' , Gennady Laptev ' , Dmitry Samoilov ' , Volodyill Damiyanovich ' , Serhii Kirieiev ' 1 Institute of Environmental Radioactivity, Fukushima University, ² Ukrainian Hydrometeorological Institute, ³ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba., 4 Chernobyl Ecocentre, State Agency of Ukraine on Exclusion Zone Management, *Corresponding author: y-igarashi@ipc.fukushima-u.ac.jp Changes in the catchment scale water balance have important social implications for usable water now and in the future. Stream discharge is also directly related to radionuclides flux in the river water system. The aim of this study was to clarify the water balance in the Chernobyl Exclusion Zone (CEZ) under current and future climate conditions. A catchment scale hydrological model was used with long-term discharge data to project the future trend of radionuclides wash-off from the contaminated catchment at the CEZ in Ukraine. The Sakhan river catchment in the CEZ (51.41° N, 30.00° E) in Ukraine is one of the Pripyat river systems, and has a total surface area of 186.9 km2. We found that under the current climate, 84% of annual input (sum of rainfall and snowmelt) was consumed as evapotranspiration, and discharge was estimated to be 16%. In future climates, annual precipitation is expected to increase. However, a projected increase in the vapor pressure deficit led the consumption of precipitation as evapotranspiration and no significant increase in discharge. The study found that warmer winter and spring temperatures will decrease the snowfall, and increase the rainfall, but it was not enough to increase evapotranspiration. As a result, the peak of discharge shifted from April to March. The increase of future average discharge during the winter and spring came from a combination of (1) increasing rainfall in the winter and spring, and (2) relatively small levels of evapotranspiration, which enhanced the catchment scale water recharge in soil moisture and gave rise to greater discharge during winter and spring. The reduction of extreme river discharge from the hydrological projections could reduce the probability of high radionuclides concentration in the river water system in the future, owing to the reduction of surface runoff water from the contaminated surface soil and/or top layer of floodplain soils in the CEZ. Keywords: Chernobyl exclusion zone; water balance, hydrological model simulation, long- term observation, future prediction
チェルノブイリ規制区域を対象とした流域スケールでの現在・将来
気候下の水収支
五十嵐康記* '、マークザレズニャク'、グレップリソプイ²、恩田裕一'、脇山義史'、アレクセイコノプレフ'、舞波謙二'、ゲナディラブテフ'、ボルディミルデミャノピッチ'、ドミロリサモイロフ'、セルゲイキリエフ' ¹福島大学環境放射能研究所、²ウクライナ水文気象研究所、³筑波大学アイソトープ環境動態研究センター、 *ウクライナチェルノプイリエコセンター *責任著者: y-igarashi@ipc.fukushima-u.ac.jp流域規模の水収支の変化は、現在および将来の使用可能な水に重要な社会的影響を及ぼします。河川流量は、河川水系の放射性核種フラックスにも直接関係しています。この研究の目的は、現在および将来の気候条件下でのチェルノブイリ排除区域（CEZ）の長期水収支を明らかにし、将来気候下において流域水収支がどのように変化する字可能性があるかを示す事です。対象とした河川はプリビャチ川の水系の１つである、Sakhan流域（51.41°N、30.00°E）で総表面積は186.9 km2です。現在気候では、年降水量の84%（降雨と融雪の合計）が蒸発散として消費され、流出率は16%です。将来の気候では、年降水量が増加すると予想されます。しかし、気温の上昇は蒸発散量の増加もたらし、河川流量に有意な増加をもたらさない事がわかりました。温暖化の影響により、降雪量が減少するため融雪出水のビークが低減される事がわかりました。融雪出水という極端な河川流量の減少は、氾濫原の表面土壌から流出する放射性核種の流出頻度を下げる事が予想され、将来の河川網における放射性核種濃度の低下を促進させる可能性がある事が示されました。キーワード：チェルノブイリ規制区域、水収支、水収支モデル、長期観測、将来予測
P-2
Time series of 137Cs activity concentration in irrigation waters
collected from Kami-oguni River and Oogaki dam in Fukushima
Hirofumi Tsukada* ¹ ¹ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: hirot@ipc.fukushima-u.ac.jp Long-term surveys of 137Cs activity concentration in suspended and dissolved fractions in irrigation waters have been conducted at two locations. The first survey lasted from June 20113 to June 2019 in the Kami-oguni river located in Date City, where some of the brown rice harvested in 2011 exceeded the provisional standard. The second survey lasted from January 2017 to December 2018 in the Oogaki dam located in the difficult-to-return zone which is the largest agricultural water reservoir in Fukushima Prefecture. The collected samples were filtered through a 0.45 μ  m pore-size membrane filter, and separated into suspended and dissolved fractions. The 137 Cs in the dissolved fraction was filtered through a Cs disk (3M), and also determined 137Cs+ as a monovalent cation. It has been monitored for 7 years and the activity concentration of 137Cs decreased in both suspended and dissolved fractions in samples from the Kami-oguni river. The 137Cs activity concentration in the dissolved fraction decreased from 0.021 Bq L-1 in 2013 to 0.006 Bq L-1 in 2019, and that in the suspended fraction also decreased with a range from 22 Bq g-1 in 2013 to 10 Bq g-1 in 2019. The 137Cs activity concentration in the dissolved fraction in both surface water and lower water of the Ogaki-dam decreased, and that in the surface water at the depth of 0.5 m ranged from 0.14 Bq L-1 in 2017 to 0.099 Bq L-1 in 2018. The chemical form of 137Cs in the dissolved fraction existed as 137Cs+. On the other hand, there was no change in the 137Cs activity concentration in the suspended fraction during the two-year observation period, and that in the surface water ranged from 34 Bq g-1 in 2017 to 30 Bq g-1 in 2018. Therefore the major risk of dissolved radiocaesium transfer from irrigation water to rice has been shown to decrease over the time since the 2011 accident. Keywords: suspended fraction, dissolved fraction, 137 Cs+
福島県上小国川と大柿ダムにおける137Cs濃度の経時変化
塚田祥文* 1
'福島大学環境放射能研究所
*責任著者: hirot@ipc.fukushima-u.ac.jp 2011年の事故後長期間に亘って、灌漑水中存在形態別137Cs濃度を2地点で調査した。2011年に収穫した玄米の一部が、暫定基準価を超えた伊達市小国地区の上小国川で2013年6月～ 2019年6月、帰還困難区域にある福島県最大の農業用貯水池の大柿ダムで2017年1月～ 2018年12月に調査を行った。採取した試料は、孔径0.45 μ mのメンプランフィルターでろ過し、懸濁態と溶存態に分別し137Csを測定した。溶存態は、更にCsディスク（3M）を用いて1価の陽イオンとして存在する137Cs+を分離した。7年間に亘り観測した上小国川では、溶存態および懸濁態共に137Cs濃度が減少し、溶存態137Cs濃度は0.021 Bq L-1（2013年）から0.006 Bq L-1（2019年）、および懸濁態では22 Bq g-1（2013年）から10 Bq g-1（2019年）であった。一方、大柿ダムでは表層水および下層水中溶存態137Cs濃度はとも減少し、表層0.5 mの溶存態137Cs濃度は、0.14 Bq L-1 (2017年)から0.099 Bq L-1 (2018年)であった。溶存態137Csは、1価の陽イオンである137Cs+として存在していた。一方、懸濁態137Cs濃度は2年間の観測では変化は見られず、表層水で34 Bq g-1（2017年）から30 Bq g-1（2018年）であった。以上から、主に灌漑水からイネに移行する溶存態放射性セシウムのリスクは、2011年の事故以降、経時的に減少していることが明らかになった。キーワード：懸濁態、溶存態、137Cs+
P-3
Temporal variation in 137Cs concentrations in the Niida River water
during a rainstorm event
Takuya Niida* ¹ , Yoshifumi Wakiyama* ² , Alexei Konoplev* ² 1 Graduate School of Symbiotic Systems Science and Technology, Fukushima University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: s1972006@ipc.fukushima-u.ac.jp Previous studies have reported that a large amount of 137Cs was washed out from river catchment during floods and understanding its dynamics is important for managing water resources and for predicting transition to ecosystems. This study shows the temporal variation in 137Cs concentrations in the Niida river during rainstorm event triggered by a typhoon. At four sites in the Niida River basin (Sakegawabashi, Haramachi, Notegamikita, and Warabidaira), river water was sampled five times during a flood event in August 2016 (total precipitation 119 mm). 137Cs concentration in suspended sediment (SS) (Bq/kg) and dissolved 137Cs concentration (Bq/L) in river water were measured. The mean 137Cs concentrations in SS at Sakegawabashi, Haramachi, Notegamikita, and Warabidaira were 6400 Bq/kg, 6180 Bq/kg, 6480 Bq/kg, and 20500 Bq/kg respectively. The mean dissolved 137Cs concentrations at Haramachi and Warabidaira were 17.1 mBq/La and 34.4 mBq/L respectively. At each point, the SS concentration (g/L) and particulate 137Cs concentration (Bq/L) reached the maximum at the maximum water level, and then decreased. The dissolved 137Cs concentration gradually decreased at Haramachi, whereas dissolved 137Cs concentration at the Warabidaira increased toward the maximum water level phase and then decreased. We will discuss the factors affecting temporal pattern of riverine 137Cs concentration at the sites based on further analysis, such as measurements ion concentrations and the 137Cs / 133Cs ratio in the water. Keywords: typhoon, radiocesium, river water, suspended sediment
台風接近時における新田川河川水の137Cs濃度の経時的変化
新井田拓也* '、脇山義史* ²、Alexei Konoplev* ²
¹福島大学大学院共生システム理工学研究科
²福島大学環境放射能研究所*責任著者: s1972006@ipc.fukushima-u.ac.jp台風接近による河川の増水時に大量の137Csが流出することは既往研究で多く報告されており、その動態を把握することは重要である。本研究では、台風接近時に新田川の河川水に含まれる137Cs濃度の分析結果を示す。新田川流域内の4地点（鮭川橋、原町、野手上北、蕨平）で、2016年8月の出水イベント時（総降雨量119 mm）に、河川水を5回ずつ採取した。河川水中の浮遊砂の137Cs濃度（Bq/kg）および溶存態137Cs（Bq/L）を測定した。浮遊砂の137Cs濃度の平均値は鮭川、原町、野手上北、蕨平でそれぞれ6400 Bq/kg 、6180 Bq/kg、6480 Bq/kg、20500 Bq/ kgであった。溶存態137Cs濃度の平均値は原町地点で17.1 mBq/L、蕨平地点で34.4 mBq/Lであった。いずれの地点でも、水位最大時に浮遊土砂濃度（g/L）、懸濁態137Cs濃度（Bq/L）が最大となり、その後減少した。溶存態137Cs濃度は原町で徐々に低下するのに対して、蕨平では水位最大時に溶存態137Cs濃度の最大値が見られその後、徐々に低下した。今後、河川水中の溶存無機イオン濃度や、137Cs/133Cs比などの測定を行い、地点間の137Cs濃度の時間変化傾向の違いの要因を考察していく予定である。キーワード：台風、放射性セシウム、河川水、浮遊砂
P-4
Radiocesium concentrations in experimentally cultured carp, other fishes, and sediments of an irrigation pond in Koriyama City Misaki Usuki ¹ , Yuki Inoue ² , Tomomi Yanagita ² , Keiichi Sasaki ³ , Kenji Nanba1, Toshihiro Wada* 4 ¹ Fukushima University, School of Symbiotic System Science ²  Fukushima University, Faculty of Symbiotic System Science ³ Fukushima Inland Fisheries Experiment Station 4 Fukushima University, Institute of Environmental Radioactivity *Corresponding author:t-wada@ipc.fukushima-u.ac.jp Koriyama City has one of the largest amounts of cultured carp production in Japan. According to the monitoring results by Fukushima Prefectural Government after the Fukushima Daiichi Nuclear Power Plant accident, cultured carp has never exceeded the Japanese standard limit of radiocesium (100Bq/kgFW). The purpose of this study is to evaluate the effects of sediment removal (hereinafter, decontamination) on radioactive contamination of fish by conducting feeding experiments of carp in a relatively highly contamination pond  before (2015) /after (2018) decontamination. The 137Cs concentrations of carp, other fishes, and sediments collected before/after decontamination were measured. For carp, net cage experiments in which carp cannot contact with the sediments were conducted before/after decontamination to evaluate the potential 137Cs uptake from the sediments by comparing 137Cs concentrations of carp inside or outside of the cage (inside-carp and outside-carp, respectively). After decontamination, 137 Cs concentration in the surface layer of the sediments (average 1.56 × 104 Bq/kgDW) and that of organic fraction (250 Bq/kgDW) decreased to less than half of those before decontamination. The average 137Cs concentration of inside-carp before and after decontamination was 5.12 Bq/kgFW and 3.80 Bq/kgFW, respectively. The clear decontamination effect was found in outside-carp: mean 137Cs concentration of them significantly decreased from 22.6 Bq/kgFW to 6.17 Bq kgFW. We inferred that the decrease of 137Cs concentration of organic fraction in sediments may be one of the factors that engendered the decreased contamination level of outside-carp. Furthermore, the 137 Cs concentration of outside-carp was significantly lower than that of silver crucian carp both before/after decontamination. Keywords: irrigation pond, freshwater fish, carp, stable isotope
郡山市のため池における給餌養殖試験コイ，その他魚類，および堆
積物の放射性セシウム濃度
薄実咲'、井上雄貴'、柳田知美'、佐々木恵一'、難波謙二'、和田敏裕* * ¹福島大学共生システム理工学研究科、¹福島大学共生システム理工学類, ¹福島県内水面水産試験場, '福島大学環境放射能研究所*責任著者: t-wada@ipc.fukushima-u.ac.jp福島県郡山市における養殖コイの生産量は全国屈指である。原発事故後の福島県のモニタリングによると養殖コイの放射性セシウム濃度は基準値100 Bq/kgFWを超えていない。しかし、汚染の程度が高いため池（粪鯉池）における情報はほとんど明らかにされていない。本研究では，比較的汚染の程度が高いため池で堆積物除去前の2015年と除去後の2018年にコイ給餌養殖試験を行ない，堆積物除去（以下，除染）の効果を評価することを目的とした。除染前後で採取した堆積物とコイ，その他魚類の137Cs濃度を測定した。コイは，ため池の底泥に接触不可能な網生資内と接触可能な網生資外（以下，生資内，生資外）の２つの試験区で行った。除染により堆積物表層の137Cs濃度（平均1.56 × 104 Bq/kgDW)，堆積物表層の有機態137Cs濃度（250 Bq/ kgDW）は除染前と比べ半分以下となった。コイの平均137Cs濃度は，生實内が除染前5.12 Bq/kgFW，除染後3.80 Bq/kgFWで，両年生贄外よりも有意に低かった。生贄外では除染前22.6 Bq/kgFW，除染後6.17 Bq/kgFWへと有意に低下し、除染の効果が見られた。この要因として堆積物中の有機態137Cs濃度の低下が考えられた。また，除染前後で生贄外のコイとギンブナの137Cs濃度を比較し、両年コイの方が有意に低かった。キーワード：ため池,淡水魚,コイ,安定同位体比
P-5
Seasonal trend of Cs-137 concentration and water quality in
Abukuma River waters
Shota Moritaka ¹ , Toshihiro Wada ² , Kenji Nanba* ² 1 Graduate School of Symbiotic Systems Science and Technology, Fukushima University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: nanba@sss.fukushima-u.ac.jp Based on the long-term observations on radiocesium in Abukuma river waters, we report temporal trend and seasonal fluctuation of cesium concentration and water quality in this river waters. Observation have been made for Abukuma river at the Kuroiwa station of MLIT from March 2012 to October 2019: every week until Jun 2014, once or twice a month until May 2019 and every week thereafter. Measurements for radiocesium were made for suspended substance collected with continuous centrifuge on site and for dissolved fraction captured with Prussian-blue cartridge filters. The suspended and dissolved Cs-137 concentration was from 0.00379 to 1.20 Bq/L, and from 0.00217 to 0.0810 Bq/L, respectively. At Kuroiwa station, long-term decreasing trends were observed both for suspended and dissolved Cs-137, and the tendency was expressed by a two-component negative exponential equation. A clear seasonal fluctuation of the dissolved Cs-137 concentrations (increase in May-Sep. and decrease in Nov-Feb) especially with the sharp increase in May were observed. Since it is reported that K+ and NH4+ can exchange with radiocesium ions, and existence of dissolved organic matter can prevent radiocesium from adsorbing to soil particles, we will focus on the relationship between them. Keywords : radiocesium, Abukuma River, long-term trend, seasonal trend
阿武隈川における河川水中のCs-137濃度と水質の季節変動
森高祥太'、和田敏裕'、雛波謙二* ²
'福島大学共生システム理工学研究科
²福島大学環境放射能研究所*責任著者: nanba@sss.fukushima-u.ac.jp福島県福島市内を流れる阿武隈川において河川水中の放射性セシウムおよび水質の観測から得られた、河川水中の放射性セシウムと水質の季節的変動について報告する。阿武隈川は国土交通省黒岩水位監視所で2012年3月からおよそ週１回、2014年６月からは月１、２回、2019年５月からは再びおよそ週１回の頻度で観測を行った。河川水中の放射性セシウムは、連続遠心分離による懸濁物の回収、およびその上澄み液からのブルシアンブルーカートリッジによる溶存態セシウムの回収により測定した。懸濁態Cs-137濃度は0.00379 ~ 1.20 Bq/L、溶存態Cs-137濃度は0.00217 ~ 0.0810 Bq/Lであった。懸濁、溶存態とも長期的には減少を統けており、その傾向は2成分の指数関数式で表せた。懸濁、溶存態Cs-137濃度は5月から９月に増加し１１月から２月に減少する季節変動が見られた。また、５月に急激な増加の特徴が見られた。放射性セシウムはK+やNH4+とイオン交換を生じることや溶存有機物によって土壌への吸着を妨げられることから、これらとの関係に注目して考察を行う。キーワード：放射性セシウム、阿武隈川、長期的傾向、季節的傾向
P-6
Vertical distribution of 137Cs in bottom sediments represents long-
term dynamics of water contamination: Fukushima and Chernobyl
Alexei Konoplev* ¹ , Yoshifumi Wakiyama ¹ , Toshihiro Wada ¹ , Gennadyi Laptev ² , Valentin Golosov ³ , Maxim Ivanov ³ , Mikhail Komissarov 4 , Yasunori Igarashi 1 , Kenji Watanabe 1 , Azusa Goto 1 , Kenji Nanba 5 ' Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan ² Ukrainian Hydrometeorological Institute, Kiev, Ukraine 3 Geography Department of M.V. Lomonosov Moscow State University, Moscow, Russia 4 Ufa Institute of Biology UFRC, Russian Academy of Science, Ufa, Russia 5 Faculty of Symbiotic Systems Sciences, Fukushima University, Fukushima, Japan *Corresponding author: r701@ipc.fukushima-u.ac.jp Processes responsible for the long-term changes in environmental radioactivity after the most severe nuclear accidents at Chernobyl NPP (1986) and Fukushima Dai-ichi NPP (FDNPP) (2011) are currently high on the agenda. Bottom sediments of lakes and reservoirs provide insight in understanding the long-term dynamics of radionuclides strongly bound to sediment particles such as 137Cs. In 2018 several cores of bottom sediments were collected in the deep parts of Lake Glubokoe and Lake Azbuchin in the close vicinity of the Chernobyl NPP and in Schekino reservoir (Upa River) in Tula region of Russia. In October 2019 two bottom sediment cores were collected in a deep part of Ogaki Dam reservoir (Ukedo River), heavily contaminated after the FDNPP accident. The collected bottom sediment cores were sliced in 1 or 2-cm layers, dried and passed through 2-mm sieve, after which analyzed for 137Cs using   γ -spectrometry. The obtained 137Cs vertical distributions in sediment accumulation zones of the water bodies suggest that almost no vertical mixing of sediments occurred, the 137Cs peaks were well-defined and not diffuse ones. If sediment accumulation rates after the accident were more or less uniform, layers of bottom sediments can be attributed to certain time of sedimentation. With 137 Cs activity concentration in a given layer of bottom sediments corresponding to 137Cs concentration on suspended matter at that point in time, we were able to obtain the dynamics of particulate 137Cs after the accidents. Using experimental values of the distribution coefficient Kd, changes in the dissolved 137Cs activity concentrations in the above -mentioned water bodies have been estimated. The estimates of 137Cs activity concentrations are in reasonable agreement with monitoring data. The general trend of the particulate and dissolved 137Cs activity concentrations in case of Chernobyl can be described by the semi-empirical "diffusional" model. In case of Fukushima the reduction of 137Cs goes faster than predicted by the "diffusional" model. The research was partially supported by the Japan Society for the Promotion of Science (JSPS), Grant-in-aid for Scientific Research (B) (18H03389); Science and Technology Research Partnership for Sustainable Development (SATREPS), Japan Science and Technology Agency (JST)/Japan International Cooperation Agency (JICA) (JPMJSA1603) and by bilateral project No. 18-55-50002 of Russian Foundation for Basic Research (RFBR) and Japan Society for the Promotion of Science (JSPS). Keywords : Fukushima, Chernobyl, radiocesium, dynamics, bottom sediments
P-7
The mechanisms of dissolved radiocesium discharge through stream
system in a headwater forest catchment
Hiroaki Kato* ¹ , Satoru Akaiwa ² , Tomoki Shinozuka ² , Zul Hilmi Saidin ² , Hikaru Iida ³ , Yuichi Onda ¹ , Tadafumi Niizato 4 ¹ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ² Graduate School of Life and Environmental Sciences, University of Tsukuba ³ College of Geoscience, University of Tsukuba 4 Fukushima Environmental Safety Center, Japan Atomic Energy Agency *Corresponding author: kato.hiroaki.ka@u.tsukuba.ac.jp This study investigated the formation mechanisms of dissolved cesium-137 concentration in stream water discharged from a headwater forest catchment. The water flow rate from both spring point and the lower stream was monitored, and the concentration of cesium-137 and other ions dissolved in the water were measured. In addition, the concentration of particulate cesium-137 concentrations in suspended sediment and coarse organic matter were measured. The monitoring period was approximately one year and six months extended from June 2018 to December 2019. The monitoring results showed that dissolved cesium-137 concentration in stream water increased with increasing temperature from spring to early summer, and then decreased in summer with increasing stream flow rate. In winter, stream water tended to show slight increase of dissolved cesium-137 concentration. The concentrations of dissolved cesium-137 in stream water and soil water showed a positive correlation. Furthermore, the concentration of dissolved cesium-137 in stream water tended to increase with downstream distance (< 30 m) from the spring point to the lower part of the catchment. These results indicated that the concentration of dissolved cesium-137 in stream water showed marked seasonal changes probably in association with the dilution effects due to the fluctuation of stream water flow rate, the mixing with soil water during the stream water flowing down along channels, and the entrainment of cesium-137 from coarse organic materials deposited on forest floors and river channels. Keywords : Fukushima accident, forest headwater catchment, dissolved radiocesium, stream water, discharge
森林源頭部における水系を通じた溶存態放射性セシウムの流出メカ
ニズムの解明
加藤弘充* '、赤岩哲'、篠塚友輝'、飯田光'、恩田裕一'、新里忠史' '筑波大学アイソトープ環境動態研究センター ²筑波大学大学院生命環境科学研究科³筑波大学生命環境学群地球学類‘日本原子力機構福島環境安全センター *責任著者: kato.hiroaki.ka@u.tsukuba.ac.jp本研究では、森林源東部における渓流水に含まれる溶存態セシウム137濃度の形成機構について調査を行った。福島県浪江町の高沈着量地域に位置する森林流域を対象として、湧水及び渓流水の流量を観測するとともに、湧水・渓流水・土壌水に含まれる溶存態セシウム137濃度及び各種溶存イオン濃度を測定した。また、粗大有機物と渓流水中の浮遊砂の悪濁態セシウム137濃度を測定した。調査期間は2018年6月から2019年12月の約1年6か月間とした。観測結果から、春から夏にかけて気温の上昇とともに渓流水中の溶存態セシウム137濃度が増加し、夏には流量の増加とともに溶存態セシウム137濃度が減少する傾向が認められた。冬季にはわずかに濃度が上昇する傾向が観測された。渓流水と土壌水の溶存態セシウム137濃度は正の相関を示した。さらに渓流水の溶存態セシウム137濃度は、湧水点から下流方向（約30 m）に向かって増加する傾向を示した。以上の結果から、渓流水の溶存態セシウム137濃度は季節変化を示し、流量増加による希釈効果や、渓流水が流下する過程での土壌水との混合、林床や河道に堆積した粗大有機物からの溶出などの影響が示唆された。キーワード：福島原発事故、森林源頭部流域、溶存態放射性セシウム、渓流水、流出
P-8
Comparative behavior of radiocesium and tritium along a river-to-
coast transect
Hyoe Takata* ¹ , Michio Aoyama ² , Toshiya Tamari ³ , Junji Yamanaka ³ ¹ Fukushima University, Institute of Environmental Radioactivity ² Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ³ Kyushu Environmental Evaluation Association *Corresponding author: h.takata@ier.fukushima-u.ac.jp Of the radiocesium released to the environment after the Fukushima Daiichi Nuclear Power Plant accident, radiocesium deposited on land is continuously transported to coastal areas through the rivers. In this study, we estimate the contribution of riverine radioacesium to the coastal areas using naturally occurring tritium as a radio tracer for riverine input, and also discuss the comparative behavior of radiocesium and tritium on the coastal area. Sampling was conducted in May 2019 on rivers and coastal areas in the southern part of Fukushima Prefecture. Water samples were also collected in the downstream of the Tomioka River and its nearest coastal area from July to October 2019. Dissolved radiocesium (137Cs) in rivers in the southern part of Fukushima Prefecture ranged from 0.71 to 4.5 Bq /m3. In the coastal areas (salinity: 27-32) dissolved 137Cs concentration varied in a range of 3.6-5.8 Bq /m3, which was higher than that of rivers. In the downstream of the Tomioka River dissolved 137Cs ranged between 8.5 and 19 Bq/m3, but varied in a wide range of 9.9-86 Bq/m3 in the coastal water (salinity: 29-34), while tritium concentration had almost constant values of 71-100 Bq/m3. The highest value in the coastal water was observed after the Typhoon Hagibis in October 2019. A discussion about the contribution of riverine input to the ocean in relation to desorption from riverine particles on estuarine mixing will be made in the presentation. Keywords : tritium, cesium, river, coastal area, Typhoon Hagibis
河川から海洋への寄与と天然起源トリチウムを考慮した福島沿岸の
セシウムとトリチウムの挙動
高田兵衛* ¹、青山道夫²、玉利俊哉³、山中潤二³ ¹福島大学環境放射能研究所²筑波大学アイソトープ環境動態研究センター ³九州環境管理協会*責任著者: h.takata@ier.fukushima-u.ac.jp福島第一原子力発電所の事故により環境中に放出された放射性セシウムのうち、陸域に沈着した放射性セシウムは、河川等を通じて沿岸域に難続的に供給される。そこで、トリチウムを指標とした河川から海洋への放射性セシウムの寄与を見積もることを試みるとともに、沿岸での放射性セシウムとトリチウムの举動の違いについても議論する。調査は2019年5月において、福島県南部の河川及び沿岸を、7 ～ 10月において、富岡川下流及びその河口付近の沿岸(富岡沿岸)において河川水と海水を採取し、ろ過後、ろ液中の放射性セシウムとトリチウムを測定した。福島県南部の河川中の溶存態放射性セシウムは0.71 ～ 4.5Bq/m3であった。沿岸（塩分：27 ～ 32）においては3.6 ～ 5.8Bq/ m3であり、河川よりも高い結果となった。一方、富岡川下流の溶存態放射性セシウムは8.5 ～ 19 Bq/m3であった。苗岡沿岸（塩分：29 ～ 34）においては9.9 ～ 86 Bq /m3であったが、トリチウム濃度は71 ～ 100 Bq/m3と大きな変化は見られなかった。なお、溶存態セシウムの最大値は台風19号後に採取した宮岡沿岸試料であった。発表では懸濁粒子からの放射性セシウムの溶脱との関連性も含めて、河川から海洋への寄与について議論する。キーワード：トリチウム、台風19号、懸濁態放射性セシウム、溶脱
P-10
Development of a model to reproduce 137Cs dissolution from dam lake
sediment considering temperature and dissolved oxygen condition Hideki Tsuji* ¹ , Seiji Hayashi ¹ , Hironori Higashi ¹ ,Kazuyuki Sakuma ² , Kazuya Yoshimura ² , Hironori Funaki ² , Takahiro Nakanishi ² , Tadahiko Tsuruta ² ¹ National Institute for Environmental Studies ² Japan Atomic Energy Agency *Corresponding author: tsuji.hideki@nies.go.jp In the dam lake near the Fukushima Dai-ichi Nuclear Power Plant, dissolution of 137Cs from the lake bottom sediment accelerated with high water temperature with low dissolved oxygen concentration (presented at the 4th IER Progress Report Meeting, 2018). As a chemical mechanism, the dissolution rate of 137Cs is mainly determined by the kinetics of NH4+ and other co-existing substances in pore water and above water. In this study, we constructed a numerical model to reproduce the distribution of dissolved 137Cs concentration in sediment pore water and diffusion of 137Cs from sediment to above water and applied this model to the results of a static dissolution experiment using undisturbed sediment core collected in the central part of the Yokokawa Dam Lake in Fukushima Prefecture. Under the assumption that dissolved 137Cs in the pore water was supplied by the microbial decomposition of organic matter and the chemical redistribution between mineral particles and pore water, parameters such as the decomposition rate of organic matter depending on temperature and dissolved oxygen concentration was incorporated into the calculation formula with reference to literature values. We also assumed that the equilibrium of 137Cs between solid and liquid phase in sediment was determined by Radiocesium Interception Potential (Wauters et al., 1994) which regulates the distribution coefficient of 137Cs by the K+ and NH4+ concentration in pore water, and also introduced the rate at which the distribution equilibrium was reached (Fiengo-Perez et al., 2015). The vertical distribution of dissolved 137Cs concentration and 137Cs diffusion to the above water under both anaerobic and aerobic conditions were well reproduced by this model. In the future, this model would be improved by incorporating experimental results on sediment properties such as the decomposition rate of organic substances. Keywords : sediment, dam lake, 137Cs, dissolution, diffusion
溶存酸素濃度環境を考慮したダム湖底質からの137Cs溶出現象再
現モデルの構築辻英樹* ¹、林誠二¹、東博紀¹、佐久間一幸¹、吉村和也²、舟木泰智²、中西貴宏²、鶴田忠彦² '国立環境研究所²日本原子力研究開発機構*責任著者: tsuji.hideki@nies.go.jp福島第一原子力発電所近傍のダム湖では湖底堆積物からの137Cs溶出が生じており、湖底の水温上昇および酸茶濃度の低下に伴って137Cs溶出速度は上昇する（第4回IER成果報告会にて既発表)。化学的メカニズムとして、137Cs溶出速度は主に間隙水および直上水中におけるNH4+等の共存溶存物質の動態によって規定されることから、本研究では底質中および底質から直上水への137Csの拡散移動現象を再現するモデルを構築し、福島県横川ダム湖心部の不撹乱底質試料を用いた静置溶出試験における底質問隙水中137Cs濃度分布等の結果に対する適用を試みた。底質固相から間隙水への137Cs供給量は有機物の微生物分解と鉱物粒子－間隙水間の化学的再分配によって規定されるという前提のもと、有機物分解速度等のバラメータを計算式に組み込んだ。また底質中の137Csの固液間分配は放射性セシウム捕捉ポテンシャル(Wautersら、1994)の式によって平衡状態が定められると仮定し、間隙水中のK+•NH4+濃度から137Cs分配係数を求め、さらに分配平衡に達するまでの速度を考慮した式(Fiengo-Perez et al., 2015)を導入した。各バラメータを文献値の範囲等で変動させ適用した結果、嫌気および好気条件における溶存態137Cs濃度の底質中鉛直分布および直上水への拡散速度を同時に再現することができた。今後は有機物分解速度等を別途測定することでモデルの精緻化を進める必要がある。キーワード：ダム湖、底質、137Cs、溶出、拡散モデル
P-9
Temporal variations in riverine 137Cs and 129I concentrations under
high-flow events
Yoshifumi Wakiyama* ¹ , Masumi Matsumura ² , Tetsuya Matsunaka ³ , Shigekazu Hirao ¹ , Kimikazu Sasa ²
¹ Institute of Environmental Radioactivity, Fukushima University ² Accelerator Mass Spectrometry Group, University of Tsukuba ³ Institute of Nature and Environmental Technology, Kanazawa University *Corresponding author: wakiyama@ipc.fukushima-u.ac.jp Iodine-129 is one of long-lived radionuclides released by the Fukushima accident. Due to its chemically reactiveness, environmental behavior of 129I could be different from those of 137Cs. Understanding its long-term fate from terrestrial to the ocean are necessary. Although previous studies indicated large 137Cs wash-off during high flow events, there are few studies on 1291 under high-flow conditions. This study aims to elucidate transfer process of 1291 through river and presents a sampling campaign on the Abukuma River during a high flow event. River water samples were taken at the Kuroiwa site at midstream of the Abukuma River during high-flow events in July and October 2018. Suspended sediment and filtrate samples were obtained by decantation and subsequent filtration, respectively. These samples were measured for dissolved and particulate 137Cs concentrations (Bq L-1). In both events, dissolved 137Cs concentration tended to decrease and particulate 137Cs concentrations were highest at the peak water discharge due to increased suspended sediment concentrations. As of 24 January 2020, the suspended sediment and filtrate samples are being prepared for measurements with accelerator mass spectrometer for 1291/127I ratio and with ICP-QQQ-MS for 127I concentration. Based on the measurements, we will present temporal variations in dissolved and particulate 1291 concentrations and discuss differences from those of 137Cs. Keywords : 1291, 137Cs, high-flow events, river
出水時の河川水の137Csおよび129I濃度の時系列変化
脇山義史* ¹、松村万寿美²、松中哲也³、平尾茂一¹、笹公和²
¹福島大学環境放射能研究所²筑波大学応用加速器部門³金沢大学環日本海環境研究センター *責任著者: wakiyama@ipc.fukushima-u.ac.jp福島第一原子力発電所事故によって放出された長寿命の129I（半減期：1,570万年）は、高い化学的活性や137Csとの挙動の違いなどの観点から、陸から海洋への挙動を長期的に把握することが必要な核種の１つである。出水時に多量の137Csが流出することが知られているが、129Iの出水時における動態を観測した例は少ない。本研究では、河川を通じた129Iの移行プロセスの解明を目的として、阿武隈川出水時の河川水の129I濃度変化を調べ、137Csとの比較を行っている。阿武隈川中流の黒岩地点（流域面積2880 km2）において、2018年7月、10月の出水イベント時に河川水の採取を行った。河川水試料はデカンテーション・ろ過により浮遊土砂とろ液に分離し、溶存態・懸濁態137Cs濃度（Bq L-1）の測定を行った。いずれのイベントにおいても、溶存態137Cs濃度は出水期間中に時間とともに低下する傾向が見られ、懸濁態137Cs濃度は浮遊土砂濃度の上昇により、出水ビーク時に最高となった。1月24日現在、溶存態・懸濁態129Iの測定を行っている。浮遊土砂およびろ液試料の前処理後、加速器質量分析法にて129I/127I比を測定し、ICP-QQQ-MSを用いて127I濃度を測定する。得られる結果を踏まえて、出水時の懸濁態・溶存態129I濃度の時系列変化を示し、137Csの動態との違いを議論する予定である。キーワード：129I、137Cs、河川、出水
P-11
Study on transport of radionuclides in watershed environment
Takahiro Nakanishi* ¹ , Tadahiko Tsuruta ¹ , Hironori Funaki ¹ , Kazuyuki Sakuma ¹ , Tomisato Miura ² - ³ , Mitsuaki A. Yoshida 3 1 Fukushima Environmental Safety Center, Japan Atomic Energy Agency ² Graduate School of Health Sciences, Hirosaki University ³ Institite of Radiation Emergency Medicine, Hirosaki University *Corresponding author: nakanishi.takahiro@jaea.go.jp To elucidate the mechanism of transport of dissolved radiocesium to masu trout, a feeding experiment was conducted in a culture pond introduced with mountain stream water (dissolved 137Cs concentration: 0.1 - 0.2 Bq / L) using a non- contaminated bait. The 137Cs concentration in the muscle of the adult masu trout (n = 10) was relatively high, showing individual differences (30 - 200 Bq / kg-wet). Pond bottom gravel was found in their stomach, suggesting a source of 137Cs other than bait and stream water. As a result of dietary analysis using stable isotope ratios, the contribution of aquatic organisms was higher in masu trout with higher 137Cs concentration in the muscle. This suggests that the 137Cs concentration in masu trout does not exceed the Japanese limit of 100 Bq/kg for general foodstuffs by transport only from the dissolved 137Cs. Keywords : 137Cs, foodweb
流域環境における放射性物質移行挙動の解明
中西貴宏* '、鶴田忠彦'、舟木泰智'、佐久間一幸'、三浦富智²'、吉田光明* '日本原子力研究開発機構福島環境安全センター ²弘前大学院保健学研究科³弘前大学被ばく医療総合研究所*責任著者: nakanishi.takahiro@jaea.go.jp福島第一原子力発電所事故により流域環境に沈着した放射性物質について、ヤマメやアカネズミ等、ICRPの標準動物への移行及び放射線影響を評価するため、生態系と環境媒体の調査を共同で実施している。その一環として、ヤマメへの溶存態放射性セシウム移行メカニズム解明のため、渓流水（溶存態137Cs濃度：0.1 ～ 0.2 Bq/L）を導入した養殖池で清浄餌を用いた飼育実験を行った。飼育したヤマメ成魚（n = 10）の筋肉中137Cs濃度は比較的高く、個体差が見られた（30 ～ 200 Bq/kg-wet）。胃内容物に池底の砂礫が存在したことから、餌・渓流水以外の137Csソースが考えられた。安定同位体比を用いた食性解析の結果、137Cs濃度が高い個体ほど水生生物（137Cs濃度：数百～数千Bq/kg-wet）の摂食剖合が高かった。言い換えれば、溶存態137Csからの移行だけではヤマメの137Cs濃度は食品中の放射性物質に関する基準値（100 Bq/kg）を上回らないことを示唆する。キーワード：137Cs、移行、生態系
P-12
Dynamics of particulate radiocaesium in river and coastal area in
Fukushima Prefecture
Tatsuo Aono*  , Takahiro Nakanishi 2 ' National Institute for Quantum and Radiological Science and Technology ² Japan Atomic Energy Agency *Corresponding author: aono.tatuso@qst.go.jp The activity concentrations of dissolved and particulate radiocaesium in river water were monitored at Takase River and its tributary Saruta River which has a forest catchment in difficult-to-return zones. During the investigation, the terrain of river channel was completely changed due to the sediment discharge caused by heavy rains from two typhoons in October 2019. At Saruta River, the activity concentrations of dissolved 137Cs were decreased by about 50% compared to before the heavy rain. On the other hand, the change of activity concentrations of particulate 137Cs have not been observed. It is considered that the condition of the forest catchment has changed by heavy rains, as one of reasons. Keywords : radiocaesium, forested watershed
河川-沿岸における粒子態放射性セシウムの形態に関する研究
青野辰雄* '、中西貴宏²
¹量子科学技術研究開発機構²日本原子力研究開発機構*責任著者：aono.tatuso@qst.go.jp帰還困難区域の森林流域の猿田川と合流する高瀬川において、河川水中の放射性セシウム濃度について調査を行った。猿田川では、溶存態放射性セシウム-137濃度の範囲は20 ～ 200 mBq/Lであった。本流よりも支流から流入する沢水では300 mBq/Lを超え、また下流に向かって、溶存態放射性セシウム濃度が増加する傾向にあった。粒子態放射性セシウム-137濃度範囲は、10 ～ 400 mBq/Lであった。 2019年10月の台風等に伴う大雨により河川は増水し、土砂の流入に伴い地形も大きく変化した。出水後に河川中のSS濃度が高くなった傾向はあったが、粒子態放射性セシウム-137濃度に変化は認められなかった。一方で溶存態放射性セシウム-137濃度が大雨以前よりも約50％低下した。大雨による土砂流出に伴い、森林流域の状態が変化したものと考えられる。キーワード：放射性セシウム、森林流域
P-13
Evaluation of dissolved 137Cs discharge characteristics from a forested
catchment of the Ohta River
Kazuyuki Sakuma* ¹ , Kazuya Yoshimura ¹ , Takahiro Nakanishi ¹ , Hironori Funaki ¹ , Tadahiko Tsuruta ¹ , Kotaro Ochi 1 , Seiji Hayashi 2 , Hideki Tsuji 2 , Hirokazu Ozaki 2 ¹ Fukushima Environmental Safety Center, Japan Atomic Energy Agency ² Fukushima Branch, National Institute for Environmental Studies *Corresponding author: sakuma.kazuyuki@jaea.go.jp Cesium-137 leaching from decomposing forest litter is thought to be one pathway by which dissolved 137Cs enters rivers from forests (Tsuji et al., 2016). To clarify whether this process contributes or not, we studied the correlation between humin-like matter from microorganism-induced plants decomposition and dissolved 137Cs concentrations. River water samples were collected approximately once a month from April 2017 to August 2019 at 10 locations (7 locations from April 2019) from the upstream of the Ohta River in the Namie and Minamisoma districts. These samples were filtered through 0.45-μm-pore size membrane filters. Measurements of the dissolved 137Cs concentrations were made with HPGe detectors. Fluorescence intensities of humin-like matter were measured using a three dimension excitation-emission matrix (excitation wavelength: 335 nm, emission wavelength: 435 nm). A positive correlation was found between the fluorescence intensities of humin-like matter and normalized dissolved 137Cs (R2=0.17, p<0.001, 137Cs concentrations were normalized by the 137Cs inventory in the catchment). The results indicate that 137Cs leaching from forest litter because of litter decomposition can contribute to increasing the dissolved 137Cs concentration in river water in forested catchments. Keywords : forested catchment, river water, dissolved 137Cs, litter, humin
太田川森林域からの落存態137Cs流出特性評価
佐久間一幸* '、吉村和也'、中西貴宏'、舟木泰智'、鶴田忠彦'、越智康太郎'、林誠二'、辻英樹'、尾崎宏和' ¹日本原子力研究開発機構福島環境安全センター ²国立環境研究所福島支部*責任著者: sakuma.kazuyuki@jaea.go.jp森林流域から河川を通じて流出する溶存態137Csの起源の一つとして、リター分解に伴う137Csのリターからの溶出が考えられている(Tsuji et al., 2016)。本研究では直接的にリター分解が溶存態137Csの発生源として寄与していることを示すために、植物などが微生物による分解を経て形成されるフミン質（腐植物質）に着目し、フミン質と溶存態 137Cs濃度の関係を評価した。浪江町と南相馬市に位置する太田川上流の森林流域の10地点において、2017年4月から2019年8月まで(2019年4月以降は7地点)、河川水を月1程度の頻度で採水した。サンプルは実験室にて0.45 μmのメンプレンフィルターでろ過後、高純度Ge半導体検出器で溶存態137Cs濃度を測定し、3次元励起蛍光スペクトル法を用いて、フミン質様蛍光強度を測定した（励起波長335 nm、蛍光波長435 nmの値を使用)。その結果、河川水中のフミン質様蛍光強度と流域沈着量で規格化した溶存態137Cs濃度は正の相関(R2=0.17, p<0.001)を示し、森林流域から発生する溶存態137Csは、リター分解に伴って溶出していることが示唆された。キーワード：森林流域、河川水、溶存態137Cs、リター、フミン質
P-14
Radiocesium fate and transport in the soil-water environment in the
proximity of the Fukushima Daiich Nuclear Power Plant
Cameron Udy* ¹ , Tom Johnson ¹ , Ralf Sudowe ¹ , Yoshifumi Wakiyama ² , Kenji Watanabe ² , Alexei Konoplev ²
'  Department of Environment Health and Radiological Sciences, Colorado State University, Fort Collins, USA ² Institute of Environmental Radioactivity, Fukushima University, Fukushima, Japan *Corresponding author: cameron.udy@colostate.edu The objective of this research was to examine the dynamics of Cs-134 and Cs-137 in the aquatic ecosystems of the contaminated areas adjacent to the Fukushima Dai-ichi Nuclear Power Plant (FDNPP). Samples of water, suspended and bottom sediments from rivers, ponds, and a reservoir were collected. Three rivers (Niida, Abukuma, and Maeda), four ponds (Inkyozaka, Suzuuchi, and Funasawa 1& 2), and Sakashita Reservoir located in the Fukushima contaminated area were the focus of the study. Bottom sediment cores were taken from the Sakashita reservoir to analyze vertical migration of radiocesium (r-Cs).  Water samples were collected and filtered using an in-situ filtration system in the field or by using a laboratory filtration system. Dissolved Cs-134 and Cs-137 were removed from water using one of two different sorbents, a cartridge with non-woven cloth impregnated with potassium zinc ferrocyanide or a column filled with granulated Iron Ferrocyanide. Activity concentrations of Cs-134 and Cs-137 were measured via gamma- spectrometry on a high purity Germanium detector, while concentrations of major cations affecting r-Cs behavior were measured via Ion Chromatography and Inductively Coupled Plasma Mass Spectrometry (ICP/MS). Fate and transport of r-Cs in the soil-water environment was assessed and predicted using analytical empirical and semi-empirical models. Analysis of model fit to data is ongoing. Keywords : radiocesium, sediment, NPP, catchment, Fukushima, soil, vertical migration
P-15
Mapping of water age in a forested headwater catchment after the Fukushima Daiichi Nuclear Power Plant accident Koichi Sakakibara* ¹ , Maki Tsujimura ² , Sho Iwagami ³ , Kosuke Nagano ' , Yuichi Onda ³ ¹ Faculty of Science, Shinshu University ² Faculty of Life and Environmental Sciences, University of Tsukuba ³ Forestry and Forest Products Research Institute, Forest Research and Management Organization 4 Graduate School of Life and Environmental Sciences, University of Tsukuba 5 Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: k_sakaki@shinshu-u.ac.jp To understand the fate of radionuclide in environment, it is important to clarify the linkage between environmental water circulation processes and behaviors of radionuclide in environment. However, this has not been well clarified yet in headwater regions. Therefore, objectives of this research are 1) to investigate spatial distribution of water age with revealing water circulation processes by using SF6 and water isotopes as tracers, 2) to clarify the relationship between water age and dissolved radio-cesium concentration of subsurface water in a headwater catchment. The data of radio- cesium was referred from Iwagami et al. (2019). The estimated age of groundwater and spring water in the study area ranged from 0.7 to 28.8 years. The shallower groundwater (3 m below the ground surface) has younger water age than the deeper groundwater (10 - 20 m below the ground surface). Although there is no clear correlation between the water age and the dissolved radio-cesium concentration in the water, the older groundwater tends to have lower dissolved radio-cesium concentration. Moreover, a spring water has younger age (approximately 4 years); however, the high radio-cesium concentration was observed. This might be because of the interaction between spring water and litter/ soil with relatively high concentration of radio-cesium in the vicinity of the ground surface before the groundwater discharge. Keywords : water age, radio-cesium, stable isotopes of water, headwater
福鳥第一原子力発電所事故の影響を受けた山地森林における
環境水の滞留時間マッピング榊原厚一* ¹、辻村真貴¹、岩上翔¹、長野倖介¹、恩田裕一² ¹信州大学理学部²筑波大学生命環境系³森林研究・整備機構森林総合研究所‘筑波大学生命環境科学研究科²筑波大学アイソトープ環境動態研究センター *責任著者: k_sakaki@shinshu-u.ac.jp環境中における放射性物質の移行の一部は水循環を介していることから、環境水と放射性物質の動態を同時に明らかにすることが重要である。しかしながら、陸域における水・物質循環の始点である山地源流域においては本課題に関し未解明な部分が多いことが現状である。従って、本研究は山地源流域を対象として、環境水の動態把握に必要不可欠な水の年代における空間分布を示し、放射性セシウム(137Cs)濃度との関係性を明らかにすることを目的とした。水の安定同位体比、SF6をトレーサとして用い、さらにIwagami et al.(2019)で報告された137Cs濃度を解析することにより以下のことが明らかになった。研究対象地の湧水・地下水の年代は0.7 ～ 28.8年を示した。浅層地下水（深度3 m）と比較をし、より深層の地下水（深度10 ～ 20 m）は古い年代を示す傾向が示された。環境水における137Cs濃度と年代との関係に明瞭な関係性はみられなかったが、全体的に古い年代を示す水ほど137Cs濃度は低い傾向にあった。湧水の年代は、4年程度と若い傾向にあるにもかかわらず137Cs濃度は高かった。これは、地表面付近において137Cs濃度の高い土壌やリターに浅層地下水が接触した後、湧水として流出することによるものと考えられた。キーワード：水年代、放射性セシウム、水の安定同位体、源流域
P-16
Development of quantitative analysis method using radon to elucidate complex groundwater processes unique in limestone area Shunya Nakasone*  ¹ , Naofumi Akata  ² 1 Graduated School of Engineering and Science, University of the Ryukyu ² Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: k198602@eve.u-ryukyu.ac.jp In a limestone area, rainwater penetrates along eroded fissures and underground cavities typical of limestone. Therefore, it is difficult to estimate the flow path and residence time of groundwater using a conventional numerical model. The aim of this study was to estimate the behavior of groundwater in the limestone area using radon as a tracer. The samples were collected from drop water in the ceiling of the Gyokusendo cave located in Okinawa Island. The radon concentrations were measured with liquid scintillation counter (Tri-Carb2910TR, PerkinElmer) for 60 min per sample. The arithmetic mean ± standard deviation of radon concentrations were estimated to be 10.51 ± 0.71 Bq/L. The radon concentrations were observed seasonal variation with high in summer, low in winter. The average monthly rainfall was 162 mm, tending to be high in summer and low in winter. Compared to the radon concentrations, a shift of 2 to 3 months was confirmed. Rainwater exceeding about 30 mm/day was observed (22th Nov, 5th, 22th, 31th Dec), during the observation period of drop water in the cave, however the same fluctuation tendency was not observed. On the other hand, a remarkable peak (506 mm/day, 14th Dec) was observed in the drop water amount data. More than about 50 mm/day of rainwater was observed before the peak (8th, 15th, 22th Sep, 22th Oct). Since the amount of drop water data is limited, it is qualitatively suggested that a shift of about 2 to 3 months between rainwater and drop water. From the above, the relationship between the radon concentrations, rainwater and the amount of drop water suggested the possibility that radon in drop water can be used as a groundwater tracer in the Gyokusendo. Keywords : radon, groundwater tracer, limestone cave, dripping water, penetration time
石灰岩地域特有の複雑な地下水プロセスを解明するためのラドンを用
いた定量解析手法の開発
仲宗根峻也* ¹、赤田尚史²
'琉球大学大学院理工学研究科海洋環境学専攻²弘前大学被ばく医療総合研究所*責任著者: k198602@eve.u-ryukyu.ac.jp石灰岩地域において、雨水は溶食された割れ目沿いや地下空洞などに浸透するため、既存の数値モデルを用いて、地下水の流動経路やその滞留時間を推測することは困難である。本研究では、石灰岩地域の地下水挙動を把握することを目的とし、地下水トレーサーとしてラドンの適用性を評価するため、沖縄県南部に所在する玉泉洞（鍾乳洞）の天井から滲み出た滴下水中のラドン濃度を測定した。また、雨水が地下に涵糞し、天井部に到達することで滴下水として滲み出ることから、地下水の浸透時間を把握するためのバラメータとして、降水量及び滴下水量を用いた。本研究では沖縄島南部の玉泉洞において、月毎にサンプリングを行い、液体シンチレーションカウタ（Tri- Carb2910TR, PerkinElmer）で60分間測定した。また、降水量は玉泉洞近傍の地域気象観測システム（アメダス糸数観測所）を利用し、適下水量データ取得のためサンプリング地点直下に雨量計（RG3-M, Onset）を設置した。本発表では、ラドン濃度および降水量は2019年1月～ 12月、滴下水量は2019年11月～現在までのデータを示す。滴下水中ラドン濃度の算術平均値±標準偏差は、10.51 ± 0.71 Bq/Lであった。また、夏季に高く冬季に低い季節変化を示した。月間平均降水量は162 mmであり、夏季に高く冬季に低い傾向であった。ラドン濃度と比較して、2～3ヶ月のズレが確認された。また、滴下水量の観測期間中に約30 mm/dayを超える雨量が観測されたが（11/22, 12/5, 22, 31)、同様の変動傾向はみられなかった。一方、滴下水量データにおいて顕著なビーク（506 mm/day, 12/14）が観測された。ビーク以前に約50 mm/dayを超える雨量が観測（9/8, 15, 22, 10/22）された。滴下水量データが限られているため定性的ではあるが、降水と滴下水には約２～３ヶ月のズレが示唆される。以上より、上記の関係から、滴下水中ラドンが玉泉洞において、地下水トレーサーとして適用できる可能性が示唆される。キーワード：ラドン、地下水トレーサー、鍾乳洞、滴下水、浸透時間
P-17
The evaluation of radioactive cesium dynamics in forest-stream
ecosystem of mountainous watershed
Yuiko Chino  ¹ , Yoshito Oyama  ¹ , Takashi Gomi*  ¹ , Hiroto Toda T 1 Graduate school of agriculture, Tokyo University of Agriculture and Technology *Corresponding author: gomit@cc.tuat.ac.jp The fate of radioactive cesium ( 137 Cs) in forest environment has been an important topic because of the long half- life of 137Cs and the complicated forest ecosystem. Especially in manufactured cedar forests, 137Cs migrates within the linkage of stream and riparian ecosystem via food web from the cedar litter as a primary food source to the highest consumer of fish. Whereas the 137Cs contamination is strongly related to the stream-riparian ecosystem linkages, most of the previous studies about 137Cs contamination in forest ecosystem have focused on one ecosystem or some specific species. In this study, we examined temporal change of 137Cs concentration in a headwater stream-riparian catchment at Towa-region in Nihonmatsu-city, Fukushima for four seasons during two sampling periods; 2012-2013 and 2016- 2017. The 137Cs concentration significantly decreased among the sampling periods for all the samples; cedar litter from riparian and stream, terrestrial and aquatic insects, and white spotted char ( Salvelinus leucomaenis ). We also calculated ecological half-lives (Teco), which is an indicator of temporal contamination change including various environmental processes commonly applied to the long-time assessment of environmental radioactive contamination. The calculated Tecos were 1.6-3.9 years with the shortest of riparian litter and longest of stream litter. These Tecos were relatively small compared to the previous studies for Fukushima and other contaminated area, which can suggest that headwater ecosystems have faster contamination decrease because of the faster nutrient cycle. Also, the Teco values in aquatic components were larger than terrestrial components. It is estimated that 137Cs contamination in stream ecosystems decreases more slowly than riparian systems because newly supplied litter which is less and less contaminated with time is the only source of contamination in the riparian systems, while fallen litter as well as resuspension of sediment and POM can keep the contamination stable in stream ecosystems. Keywords : radioactive cesium (137Cs), forest, stream-riparian ecosystem, ecological half-life (Teco)
山地流域における渓畔林－渓流生態系における放射性セシウム動態評価
千野結子'、大山義人'、五味高志* '、戸田浩人'
'東京農工大学農学府
*責任著者: gomit@cc.tuat.ac.jpスギ人工林等の森林渓流生態系では、主要餌貧源であるスギリターから高次捕食者である魚類へ食物網を介した放射性セシウム（137Cs）の移行が確認される等、137Csの汚染は渓畔・渓流の両方の生態系に関連する一方で、多くの先行研究は片方の生態系や特定の生物種のみに注目している。本研究では、福島県二本松市東和地区の上流域における137Cs濃度の時系列変化を2012-13と2016-17の2期間において調べた。全採取項目（渓畔･渓流内のスギリター、水生・陸生昆虫、イワナ（Salvelinus leucomaenis）で137Cs濃度は著しく減少し、生態学的半減期（T ∞ ）は1.6 ～ 3.9年と計算された。これらのTeco値は先行研究と比較して小さく、上流域の渓畔･渓流生態系では栄養循環が速いため、汚染度が比較的早く減少すると考えられた。また、渓流域のTecoは渓畔域より大きく、渓畔域では汚染度の低いリターが栄養源となる一方で、渓流域では137Csを吸着しやすい堆積物やPOMの再懸濁により、高い汚染度が維持されることが示唆されたキーワード：放射性セシウム（137Cs）、森林渓流生態系、渓畔・渓流生態系、生態学的半減期（Teco)
P-18
Changes in Cs-137 concentration in dissolved form and sediment in the rivers in the difficult-to-return zone and the surrounding area, and their factors (Distribution coefficient of Cs-137 in between dissolved form and sediment) Yukio Takeuchi* ¹ , Keisuke Taniguchi ¹ , Hirotsugu Arai ¹ , Hirofumi Yoshita ¹ , Kazuki Fujita ¹ , Yuichi Onda ² ¹ Fukushima Prefectural Centre for Environmental Creation ² Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: takeuchi_yukio_01@pref.fukushima.lg.jp The Ministry of the Environment conducts the survey about the Cs-137 concentrations in the sediments and river waters in the Radioactive Material Monitoring in the Water Environment. In the survey, Cs-137 concentration in sediment was detected, however that in river water was not detected in many cases due to low level. Therefore, it enables to estimate the dissolved Cs-137 concentrations in river waters from that in the sediments, if the distribution coefficient ( Kd value) in between the sediment and the dissolved form in river water is acknowledged. In this study, to calculate the Kd value of Cs-137 in between the sediment and the dissolved form in river water, we conducted sampling of river water three times a year, and river sediment once a year in the 5 rivers in the difficult-to- return zone and the surrounding area. The sediments were taken by a core sampler (100 mL), and dried at 105° C for 48 hours. The river water was filtrated by a membrane filter with pore size of 0.45 μ  m, and was absorbed by a cation- exchange resin. The Cs-137 concentrations in both the sediment and the dissolved form in the resin, were measured by a germanium semiconductor detector. The results of Cs-137 in sediment were from 410 to 3300 Bq / kg-dry. The results of dissolved Cs-137 were in the range from N.D. (<1.5 mBq / L) to 110 mBq / L in the 5 rivers. In the poster, we will present the relationships between the Kd value and the characteristics of the catchment(land use).(253 words) Keywords : radiocaesium, river water, dissolved radiocaesium, sediment
帰還困難区域及びその周辺の河川における溶存態及び河床土の放射
セシウムの濃度変化とその要因（溶存態－河床土のCs-137分け
竹内幸生* '、谷口圭輔'、新井宏受'、吉田博文'、藤田一輝'、恩田裕一年
'福島県環境創造センター ²筑波大学*責任著者: takeuchi_yukio_01@pref.fukushima.lg.jp環境省は、水環境における放射性物質モニタリングとして、河床土と河川水の調査を実施している。その中で、河床土のCs-137濃度について定量されているが、河川水についてはCs-137濃度が低く定量できていない場合が多い。従って、河床土と河川水中の溶存態の間でのCs-137の分配係数（Ka値）が既知であれば、定量できている河床土のCs-137濃度から、定量が難しい溶存態Cs-137濃度の推定が容易となる。本研究では、河床土と溶存態の間でのKa値を算出することを目的とし、帰還困難区域及びその周辺に位置する5つの河川で、年１回の河床土採取と年３回の採水調査を行った。河床土は、採土器（100 mL）を用いて採取し、48時間105°  Cで乾燥した。溶存態の試料は、0.45 μ mのメンブレンフィルタでろ過した後、陽イオン交換樹脂に吸着させた。河床土と溶存態のCs-137濃度を、Ge半導体検出器を用いて測定した。結果より、河床土は、410 ～ 3300 Bq/kg-dryであった。一方、溶存態Cs-137濃度は、N.D.(<1.5 mBq/L) ～ 110 mBq/Lであった。発表では、Kd値と流域の特徴（土地利用状況）との関係に関する解析結果も併せて示す。（437字）キーワード：放射性セシウム、河川水、溶存態セシウム、河床土
P-19
Study on the discharge of radioactive cesium from a forest basin in northern Fukushima and the sedimentation mechanism in the
reservoir
Takuya Kawai 1 , Nobuhito Ohte* 1 , Naoto Nihei 2 , Toshihiro Wada i 1 Graduate School of Informatics, Kyoto University ² Graduate School of Agricultural and Life Sciences, University of Tokyo ³ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: nobu@i.kyoto-u.ac.jp After the Fukushima Daiichi nuclear power plant accident in March 2011, radioactive cesium (Cs), which has fallen into forest areas in the northern Fukushima prefecture, is now concentrated in the organic layers of the forest floor and the near surface horizons of soil profiles, and partly circulated between vegetation and soils. In the future, from the forest that is not decontaminated, these statically and dynamically stored radioactive Cs will flow out during storm events, and some will be deposited along with sediment in many agricultural reservoirs located in the middle stream. In order to quantitatively elucidate the mechanism of radioactive Cs outflow through forest mountain streams and the sedimentation mechanism in reservoirs in the reservoirs, time sequential observation of radioactive Cs outflow from forest areas during storm events caused by typhoons and a survey was conducted on radioactive Cs in the sediments in the downstream reservoir. Result showed that during a large-scale rainfall event, it was possible to estimate and evaluate the characteristics of the time-dependent changes in the amount of radioactive Cs flowing out together with the suspended sediment, changes in the form of runoff, and the trapping effects of the reservoir. Keywords : radioactive cesium, forested catchment, reservoir, discharge and sedimentation mechanism, northern Fukushima
福島県北部森林流域からの放射性セシウムの流出と貯水池における堆
積メカニズムに関する研究
川井拓哉'、大手信人* '、二瓶直登'、和田敏裕' ¹京都大学院情報学研究科²東京大学大学院農学生命科学研究科³福島大学環境放射能研究所*責任著者: nobu@i.kyoto-u.ac.jp 2011年の福島第一原発事故によって、県北部の森林地帯に降下した放射性セシウム（Cs）は、現在、林床の有機物層、土壌表層などに酱積が集中し、一部は植生との間で循環している。今後、除染がされない森林からは、これら静的・動的に貯留されている放射性Csが降雨イベント時に流出し、中流に位置する多くの農業用貯水池で、一部は土砂とともに堆積する。森林渓流を通じた放射性Csの流出と中流域の貯水池における堆積のメカニズムを定量的に明らかにすることを目的として、台風による降雨・流出イベント時の森林域からの放射性Cs流出の経時的観測とその下流部の貯水池における土砂･放射性Csの堆積状況に関する調査を実施した。これによって大規模降雨イベント時、士砂とともに流出する放射性Cs量の経時変化の特徴と、流出形態の変化、貯水池の捕捉効果を推定・評価することができた。キーワード：放射性セシウム、森林流域、貯水池、流出・堆積機構、福島県北部
P-20
Fractional analysis of radiocesium in pond water in difficult- to-return
zone Tomijiro Kubota* ¹ , Hirofumi Tsukada ² ¹ National Agricultural Research Organization ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: tomi@affrc.go.jp Fractional analysis of radiocesium of water was executed at 24 irrigation ponds located in the difficult-to-return zone in the Fukushima Prefecture from July through August of 2019.  As a result, radioactive cesium (Cs-137) contained in water in the investigation pond was in total in the range of 0.6-6.0Bq/L and the mean value was 2.35Bq/L.  Of these, dissolved Cs-137 was 14% in average (range: 2-35%) , exchangeable Cs-137 was 56% (range:11-90%), organic Cs-137 was 8%(range:0-27%), and other was 22% (range: 1-57%).     Exchangeable form of Cs-137 easily shifted to dissolved form of Cs-137 when the cation exists in water were over 50 percent of total Cs-137. Keywords : irrigation pond, fractional analysis
帰還困難区域内のため池における形態別放射性Csの分画分析
久保田富次郎* '、塚田辟文'
'国立研究開発法人農業・食品産業技術総合研究機構²福島大学環境放射能研究所*責任著者:tomi@affrc.go.jp福島県浜通り地方の帰還困難区域内に立地する農業ため池24ヶ所において、2019年7月から8月にかけて水賀調査を行い、水中の放射性Csの形態別分析を実施した。その結果、調査ため池における水中に含まれる放射性セシウム（Cs-137）は、トータルで0.6 ～ 6.0Bq/Lの範囲にあり平均値は2.35Bq/Lであった。このうち、溶存態Cs-137は、平均で14%(2 ～ 35%)、交換態Cs-137は平均で56% (11 ～ 90%)、有機態Cs-137は平均で8%(0 ～ 27%)、その他(結合態等）は平均で22%(1 ～ 57%)であった。これらのうち交換態Cs-137は、水中に陽イオンが存在すると容易に溶存態Csに移行する形態であるが、今回の調査では水中のCs-137の5割強を占めることがわかった。キーワード：ため池、分画分析
P-21
Radiocaesium dynamics in forested watersheds in Fukushima
Prefecture
Keisuke Taniguchi* ¹ , Yukio Takeuchi ¹ , Kazuki Fujita ¹ , Terumi Dohi ² , Seiji Hayash ³ , Takayuki Kuramoto ' , Naoki Nomura 5 , Tatsuo Aono 6 ¹ Fukushima Prefectural Centre for Environmental Creation ² Japan Atomic Energy Agency ² National Institute for Environmental Studies 4 Tokai University 5 Fukui University of Technology 6 National Institute for Quantum and Radiological Science and Technology *Corresponding author: taniguchi_keisuke_01@pref.fukushima.lg.jp In Fukushima Prefecture, although decontamination has been completed except for difficult-to-return areas, most of forests have not been decontaminated yet. From forests, radiocaesium may enter rivers and affect downstream areas. A survey was conducted in three forested watersheds of the Nanokazawa, Saruta, Nuno rivers located in Fukushima Prefecture to understand the amount and characteristics of radiocaesium flowing out. In each watershed, suspended solids (SS) were collected by a suspended sand sampler, water was collected every few months, and the water level and flow rate were measured. After freeze-drying the SS sample, the concentration of suspended Cs-137 was measured by a germanium semiconductor detector. The water sample was filtered through a membrane filter with a pore size of 0.45 μ m, then the dissolved Cs-137 was collected by the solid-phase extraction disk method or AMP coprecipitation method, and the dissolved Cs-137 concentration was measured by a germanium semiconductor detector. The ranges of dissolved Cs-137 concentration in FY2019 were 69-190 mBq/L in the Saruta River, 9.7-16mBq/L in the Nanokazawa river, and ND-3.2 mBq/L in the Nuno River. In the poster, we will also present the results of SS measurements and flow observations. Keywords : radiocaesium, forested watershed
福島県森林集水域における放射性セシウムの動態解析研究
谷口圭輔* ¹、竹内幸生¹、藤田一輝¹、土肥輝美¹、林誠二²、倉元隆之¹、野村直樹¹、青野辰雄¹ ¹福島県環境創造センター ²日本原子力研究開発機構¹国立環境研究所¹東海大学¹福井工業大学6量子科学技術研究開発機構*責任著者: taniguchi_keisuke_01@pref.fukushima.lg.jp福島県では、帰還困難区域を除き面的除染が完了した一方で、森林の大半は未除染のまま残されている。この森林流域から、放射性セシウムが河川に流入し下流に影響を及ぼす可能性がある。そのため、福島県内に位置する七日沢・猿田川・布川という３つの森林流域を対象に、流出する放射性セシウムの量と特徴を把握するための調査を実施した。各流域において、浮遊砂サンプラーによる懸濁粒子（SS）の捕集、数か月おきの沢水採取、水位および流量の測定を実施した。SS試料については、凍結乾燥後、ゲルマニウム半導体検出器により懸濁態Cs-137濃度を測定した。沢水試料については、孔径0.45 μ mのメンプレンフィルターでろ過したのち、固相ディスク法またはAMP共沈法で溶存態の放射性セシウムを捕集し、ゲルマニウム半導体検出器で落存態Cs-137濃度を測定した。これまでに得られた2019年4月以降の落存態Cs-137濃度の範囲は、猿田川で69 ～ 190mBq/L、七日沢で9.7 ～ 16mBq/L、布川で検出下限以下〜 3.2mBq/Lであった。ポスターでは、SSの測定や流量観測の結果をあわせて紹介する。キーワード：放射性セシウム、森林流域
P-22
Migration behavior of radiocesium in river systems in the coastal area
of Fukushima Prefecture
Deddy Irawan Permana Putra ¹ , Shinya Ochiai* ² , Takahiro Nakanishi ³ , Tadahiko Tsuruta ³ , Seiichi Tomihara ⁴ , Shun Watanabe 5 , Kyuma Suzuki 5 , Seiya Nagao 2 1 Graduate School of Natural Science and Technology, Kanazawa University ² Instutute of Nature and Environmental Technology, Kanazawa University ³ Japan Atomic Energy Agency Aquamarine Fukushima 5 Gunma Prefectural Fisheries Experiment Station *Corresponding author: E-Mail: sochiai@se.kanazawa-u.ac.jp The Fukushima Dai-ichi Nuclear Power Plant accident has released a large amount of radioactive materials to the atmosphere due to the Tohoku earthquake, on March 11, 2011. This accident resulted in deposition of radioactive cesium (134Cs and 137Cs) on land, rivers and sea around Fukushima Prefecture. In this study, activity of 134Cs and 137Cs has been investigated for dissolved and particulate phase in river water in Fukushima and adjacent area (Natsui River, Tone River, Niida River, and Abukuma River) at normal and high flow condition during 2018-2019 to understand factors controlling transport of radiocesium during different condition. Suspended solids were separated using continuous flow centrifugation and dissolved cesium were co-precipitated using ammonium molybdophosphate (AMP) method. The AMP precipitated and suspended solids were dried to determined radioactive cesium concentration using HPGe gamma spectrometry. The maximum concentration of 134Cs and 137Cs at normal condition was 0.7 mBq L-1 and 7.9 mBq L-1 in the Tone River, and 1.1 mBq L-1 and 11 mBq L-1 in the Natsui River, respectively. The concentration of 134Cs and 137Cs in river water was increased after the rainy events at high flow conditions. Total concentration of 134Cs after the rainy events in the Tone River and the Natsui River was 18–37 mBq L-1 and 40 mBq L-1, and concentration for 137Cs was 210-411 mBq L-1 and 447 mBq L-1, respectively. During the study period, 96- 100 % of 134Cs and 137Cs was distributed by suspended solid in the Tone River and 99-100 % of 134Cs and 137Cs in the Natsui River after the rainy events. These results indicate that behavior of suspended solids is a main factor controlling variation of concentration of 134Cs and 137Cs in both rivers. In this presentation, these results are compared with the data obtained from Niida River and Abukuma River. Keywords : radioactive cesium, river water, Fukushima Daiichi Nuclear Power Plant
福島県沿岸域の河川水系における放射性セシウムの移行動態
Deddy Irawan Permana Putra ¹、落合伸也*²、中西貴宏²、鶴田忠彦²、冨原聖一'、渡辺岐'、鈴木究真'、長尾誠也²
¹金沢大学自然科学研究科
²金沢大学環日本海域環境研究センター ³国立研究開発法人日本原子力研究開発機構4公益財団法人ふくしま海洋科学館5群馬県水産試験場*責任著者: sochiai@se.kanazawa-u.ac.jp本研究では様々な環境条件の河川における福島第一原子力発電所事故由来の放射性セシウムの移行動態を把握するため、2018年から2019年にかけて福島県および周辺地域（夏井川、利根川、新田川、阿武隈川）の河川水中の溶存態・態濁態放射性センウム（134Cs、137Cs）濃度の観測を行った。平水時における河川水中の全134Csおよび137Cs濃度は、夏井川では最大でそれぞれ1.1 mBq L-1 、11 mBq L-1、利根川では0.7 mBq L-1 、7.9 mBq L-1であった。降雨イベント時ではこれらの濃度は増加し、全134Csおよび137Cs濃度は夏井川においては40 mBq L-1、447 mBq L-1、利根川では18–37 mBq L-1、210–411 mBq L-1であった。これらの降雨イベント後には夏井川においては99-100 %、利根川では96-100 %の放射性セシウムが懸濁態として存在していた。このことは河川水中の放射性セシウムの濃度の支配要因として懸濁粒子の挙動が重要であることを示している。本発表ではこれらの結果を新田川、阿武隈川における観測結果との比較を行う。キーワード：放射性セシウム、河川水、福島第一原発事故
P-133
Current status and issues of decontaminated paddy field resulted from
rice production experiments in mountainous area
Hiroaki Matsuoka ¹ *, Yoshinari Suzuki ¹ , Masaaki Saito ² , Kazuki Togami ³ , Osamu Nagata 4 , Takuro Shinano ² ¹ Fukushima Agricultural Technology Center, ² Agriculture and forestry office in middle area of Fukushima prefecture ³ NARO Tohoku Agricultural Research Center 4 Agricultural Radiation Research Center, NARO Tohoku Agricultural Research Center 5 Hokkaido University *Corresponding author: matsuoka_hiroaki_01@pref.fukushima.lg.jp Radioactive cesium deposited on the soil surface of cropland in Fukushima prefecture after accident of the Fukushima Daiichi Nuclear Power Plant in 2011. As a result, paddy fields in a part of mountainous area had been restricted to any farming. After decontamination of radionuclides from soil surface, rice production was allowed to resume. The decontamination by stripping the topsoil and topdressing with uncontaminated soil was expected to reduce the concentration of radioactive cesium in soil. Meanwhile, loss of soil fertility was concerned. Therefore, it is necessary to grasp current situations of soil fertility in decontaminated paddy field, and to establish techniques improving such soil after rice production was resumed. The aim of study is to evaluate soil fertility of paddy field decontaminated radioactive cesium in 2014, and the effect of applying cattle manure continuously when rice production was resumed after 1, 2, or 4 year of the decontamination. Low soil fertility was observed when rice was cultivated after 1 year and 2 year of the decontamination. When rice farming was started after 4 year of the decontamination, the decrease of soil fertility was slightly remained. Continuously applied manure was contributed to improve soil fertility. We will discuss some current issues of decontaminated paddy fields based on each soil fertility in our poster presentation. Keywords : radioactive cesium, paddy field after decontamination of radionuclide, mountainous area
中山間地域における除染後水田での水稲栽培試験からみる現状と課題
松岡宏明* '、鈴木芳成'、斎藤正明'、戸上和樹'、永田修'、信濃卓郎'
¹福島県農業総合センター ²福島県県中農林事務所³農研機構・東北農業研究センター ‘農研機構・東北農業研究センター福島研究拠点農業放射線研究センター 5北海道大学大学院*責任著者: matsuoka_hiroaki_01@pref.fukushima.lg.jp福島第一原子力発電所の事故により放射性セシウム(RCs)が福島県内の農地に降下した結果、中山間地域の一部では水稲の作付けが制限され、水田の除染後にその制限が解除された区域があった。その除染方法は、作土表層を剥ぎ取った後に近隣の山土による客土を実施したことから、土壌中のRCsが低減する一方で、地力の低下が懸念された。そのため、除染後水田での地力の把握と、その回復技術が求められた。そこで、除染完了した2014年から1、2、および4年後と、水稲の作付け再開年度が異なる水田において、得られた玄米の収量と県が定める目標収量との比較に加えて、土壌分析から地力の実態を明らかにした。また、牛ふん堆肥連用による地力回復への影響を解析した。除染完了の1、2年後に水稲の作付けを再開・継続すると、顕著だった地力の低下が徐々に改善された。一方で、4年後からの作付け再開開場では、地力の低下は軽微であった。また、いずれの囲場でも牛ふん堆肥の連用は、地力の回復に寄与した。発表では除染後の地力に基づく課題を議論する。キーワード：放射性セシウム、除染後水田、中山間地域
P-134
Horizontal distribution of radiocesium in soil on farmland after
decontamination in evacuation zones
Takashi Saito* ¹ , Tomoaki Nemoto ¹ , Tsukasa Ono ¹ , Minoru Tanigaki ² ¹ Hama-Agricultural Regeneration Research Centre, Fukushima Agricultural Technology Centre ² Institute for Integrated Radiation and Nuclear Science, Kyoto University *Corresponding author: saito_takashi_01@pref.fukushima.lg.jp After the Fukushima accident, the distribution of the concentration of radiocesium (RCs) in the contaminated farmland had been investigated in Fukushima prefecture, however, the horizontal distributions of RCs variations in adjacent field and within the field have not been reported yet. In addition, to remove RCs deposited on agricultural land in evacuation zones, fertile surface soil has been removed and replaced with low-fertility sandy soil taken from mountainous areas, it has been reported that there is the large variation in RCs in the farmland. We evaluated the effect of horizontal distribution of RCs variations among adjacent farmland and within the farmland after decontamination in evacuation zones. We investigated the horizontal distributions of Cs-137 in 36 different paddy fields in Tomioka town. The Cs- 137 concentrations in the depth of 0-15 cm soil collected from 36 paddy fields were 246-2390 Bq/kg DW, showing approximately ten-fold variations. The Cs-137 concentrations in the depth of 0-5 cm of 60 plots within one field in 36 different paddy fields were 226-3100 Bq/kg DW, showing approximately fourteen-fold variations. Most of these paddy fields were not well-mixed because no crops are planted and only about two or three times a year during the maintenance management period. Furthermore, since the soil was not uniformly distributed by decontamination of the topsoil, it was considered that the variations of the Cs-137 in the field were expanding. Keywords : soil, decontamination, Cs-137
避難指示区域等の除染後農地における土壌中放射性セシウム等の分布
実態
窩藤隆* ¹、根本知明' 、小野司' 、谷垣実* '福島県農業総合センター浜地域農業再生研究センター ²京都大学複合原子力科学研究所*責任著者: saito_takashi_01@pref.fukushima.lg.jp東京電力福島第一原子力発電所の事故後、県内全域および市町村毎の土壌中放射性セシウム（以後RCs)濃度の分布実態について報告されているが、地域内の土壌中RCs濃度の詳細な分布実態については報告が少ない。加えて、避難指示区域の大部分の農地では表土剥ぎ＋客土による除染が実施され、ほ場内の地力ムラやRCsの分布ムラが指摘されている。このため、避難指示区域内の隣接した除染後農地群において、従来の土壌採取方法により地域内およびほ場内の土壌中RCs濃度の分布実態を明らかにした。宮岡町の除染後農地群36ほ場から5点法により土壌を採取するとともに、その中の1ほ場については60点の土壌を採取した。除染後農地群36ほ場のCs-137濃度を測定した結果、246 ～ 2,390Bq/kg乾土であり、約10倍の差が見られた。また、ほ場内の60点のCs-137濃度を測定した結果、226 ～ 3,100 Bq/kg乾土であり、約14倍の差が見られた。供試ほ場の大部分は農作物が作付されておらず、保全管理により１年間に２～３回程度しか耕起されていないことから、十分に混和されていない。さらに、表土剥ぎ除染後は均一に客土が実施されていないことから、ほ場内のCs-137濃度のバラツキが拡大していると考えられた。キーワード：土壌、除染後農地、Cs-137
P-23
Spatio-temporal variability of radiocesium concentration in coastal
sediment off Fukushima
Shotaro Suzuki* ¹ , Yosuke Amano ¹ , Akira Matsumoto ² , Kyoichi Kamiyama ¹ 1 Fukushima Prefectural Fisheries and Marine Science Research Centre ² Fukushima Prefectural Research Institute of Fisheries Resources *Corresponding author: suzuki_syoutaro_01@pref.fukushima.lg.jp A large amount of radionuclides were released into marine environment by the accident of the Fukushima Dai- ichi Nuclear Power Plant (FDNPP). Monitoring investigation of radiocesium (137Cs) concentration in sediment is important to understand fishing ground condition for proving the safety of fisheries products. Our previous study suggested decreasing trend of 137Cs concentration in coastal sediment off Fukushima. However, there was no information about its spatio-temporal variability, especially, including recent trend. Here, monitoring data between Mar. 2011 and Feb. 2019 were analyzed to describe spatio-temporal variability of 137Cs concentration in coastal sediments off Fukushima (Total eight lines observation in Soma-Futaba area and Iwaki area). Additionally, Radiometric Environment Survey and Quantification (RESQ hose, Thornton et al. 2013) were used to get continuous trend of 137Cs concentration in the sediment. 137Cs concentration of sediment had decreasing trend and model fitting showed that decreasing rate became slow in the both Soma-Futaba area and Iwaki area. Spatial (local scale) variability was also observed and 137Cs concentration was lower in two lines (Isobe and Shinchi lines) and Ena line than other lines in Soma-Futaba area and Iwaki area, respectively. In addition, RESQ hose data showed highly concentrated 137Cs near the FDNPP (around 37° 26' N, 141 12' E) between 2015 and 2018 observation. These results suggested that 137Cs concentration had spatio-temporal variability in the sediment off Fukushima and its variability might be related to environmental factors such as river and topography. Keywords : radiocesium, sediments
福島県沿岸域における海底土の放射性セシウム濃度の時空間的変動
鈴木翔太郎* ¹、天野洋典¹、松本陽²、神山亨一¹
¹福島県水産海洋研究センター
²福島県水産資源研究所*責任著者: suzuki_syoutaro_01@pref.fukushima.lg.jp東京電力福島第一原子力発電所（以下、1F）の事故の影響により、福島県沖の海底土から放射性セシウム（137Cs）が検出された。当県では事故直後から137Csのモニタリング調査を行い、漁場における海底土の137Cs濃度を把握している。これまでの調査で137Cs濃度の低下を確認できているが、137Cs濃度の時空間的変動については、よくわかっていない。そこで2011年5月から2019年2月までに松川浦、相馬双葉海域およびいわき海域の計8定線で行った緊急時環境放射線モニタリングと2015年から2018年までに曳航式ガンマ線計測装置（Radiometric Environment Survey and Quantification; RESQ hose, Thornton et al. 2013）により観測した連続的な海底土の放射性Cs濃度から、当県全域の海底土における放射性Cs濃度の時空間的変動を俯瞰した。緊急時環境放射線モニタリングの結果では、海底土中の137Cs濃度は低下傾向を示していたが、モデルによる解析から低下速度の鈍化が示された。また、空間的な変動も確認され、相馬双葉海域では新地沖と磯部沖、いわき海域では江名沖の濃度が他各海域の定線よりも低い傾向を示した。 RESQ hoseによる海底土の連続測定では、東経141度12分、北緯37度26分付近（水深75m）で比較的高濃度の137Csが検出された。以上の結果から、福島県沖の137Cs濃度には時空間的な変動がみられ、これらの変動は河川からの137Csの流入や地形による沈着のされやすさなど環境との関連性が示唆された。キーワード：放射性セシウム、海底土
P-24
Tracing the sources of Pu and Hg in the deep-sea sediments using
Pu and Hg isotopes
Wang Zheng* ¹ , Holger Hintelmann ² , Wei Dong ³ , Jian Zheng* 4
¹ Institute of Surface-Earth System Science, Tianjin University, China ² Department of Chemistry, Trent University, Peterborough, Canada 3  State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, China 4  Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, Japan *Corresponding author: zhengw3@tju.edu.cn, zheng.jian@qst.go.jp Radionuclides (e.g., Pu) and heavy metals (e.g., Hg) are important pollutants in marine environments. However, the sources and distribution of these contaminants in the Southern Hemisphere are rarely studied. In this project, we measured 239+240Pu activities and 240Pu/239Pu atom ratios, as well as Hg concentration and isotope compositions in deep-sea sediments in the South Pacific for the first time. Extremely low 239+240Pu inventories in sediments of the South Pacific revealed relatively less fallout compared with that of North Pacific. The 240Pu/239Pu atom ratios in the sediments are typically lower than the global fallout, suggesting mixing with low ratio Pu generated by French Nuclear Tests and/or the United Kingdom Nuclear Tests in Australia. The plausible pathways for Pu transportation were the South Pacific Gyre, based on the observation of latitudinal trends in both the 239+240Pu inventories and 240Pu/239Pu atom ratios. Hg in the South Pacific is most likely contributed by global atmospheric circulation, although the contribution from ocean current remains to be studied. Total Hg concentration (THg) and isotope ratios are measured in one sediment core in the Antarctic sea, where local anthropogenic Hg sources are absent. The bottom of the core shows low THg (<10ppb) and significantly negative     δ  202Hg values that are consistent with the global background of atmospheric Hg(II), suggesting a relatively low anthropogenic influence. The upper section of the core shows much higher THg (up to 45.6 ppb) and   δ  202Hg values approaching zero, consistent with the increased global anthropogenic Hg emission (e.g., from coal combustion) in recent years, probably transported via long range atmospheric circulation. Future work will compare Pu and Hg isotopes in South Pacific sediments to reconstruct the history of anthropogenic inputs of these contaminants to marine environments, and to assess the influence of human activities at local vs. global scales. Keywords : South Pacific, plutonium, mercury, isotope, radionuclide, heavy metal
P-25
after the Fukushima nuclear accident
Fenfen Wang ¹,³ Wu Men ¹ , Jian Zheng* ² , Shaoming Pan* ³ ¹ Third Institute of Oceanography, Ministry of Natural Resources, China ² National Institutes for Quantum and Radiological Science and Technology, Japan 3 School of Geographic and Oceanographic Sciences, Nanjing University, China *Corresponding author: zheng.jian@qst.go.jp, span@nju.edu.cn Studying the artificial radionuclides in sediment cores is important to understand the history of contamination, material sources, and sedimentary environment. In this study, Pu isotopes (239Pu, 240Pu and 241Pu) and Cs isotope (137Cs and 134Cs) were determined for 4 abyssal sediment cores collected in 2013-2018 in the Northwest Pacific (NP2, 146.5° E, 35° N; NP3,145° E, 31° N) and NP4(148° E, 27° N) and mid-East Pacific Ocean (EP, 155° W, 10° N). 239+240Pu activities ranged from 0.0018 to 0.72 Bq/kg with the 240Pu/239Pu atom ratios of 0.070-0.246; 137Cs activities ranged from <LOD to 17.9 Bq/kg, and 134Cs activities were <LOD. Generally, 239Pu, 240Pu and 137Cs penetrated to the depth of ~10 cm in the sediment cores, which is caused by particle mixing due to burrowing activities of benthic fauna. With a few exceptions, the activities of 239+240Pu and 137Cs in the 4 sediment cores decreased generally with the increasing depth. The estimated 137Cs inventory in core NP2 was 104.6 Bq/m2. The estimated 239+240Pu inventories (Bq/m2) of sediment cores NP2, NP3, NP4 and EP were 23.0, 0.87, 0.83 and 8.1, respectively. The "latitude effect" of the global fallout deposition resulted in more deposition in NP2 and the weak scavenging ability of the overlying water column caused much lower deposition in NP3 and NP4. 240Pu/239Pu atom ratio showed Pu in NP2, NP3 and NP4 were from the global fallout and PPG close-in fallout (6% - 46% contribution). 240Pu/239Pu atom ratios of EP ranged from 0.070 to 0.184, suggesting contributions of the source(s) with lower 240Pu/239Pu atom ratio and the global fallout, and was less affected by the PPG close-in fallout. In a comprehensive judgement of 240Pu/239Pu atom ratios and 239+240Pu activities, we concluded there was no evidence of Pu signal derived from the Fukushima nuclear accident. Keywords : 39Pu, 240Pu, 137Cs, 240Pu/239Pu atom ratio, sediment core, Pacific Ocean, Fukushima nuclear accident
P-26
Study of radiocesium contamination of marine fishes in Fukushima
Prefecture
Shotaro Suzuki ¹ , Yosuke Amano* ¹ , Kyoichi Kamiyama ¹ , Toshihiro Wada ² ¹ Fukushima Prefectural Fisheries and Marine Reserch Centre ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: yousuke_amano_01@pref.fukushima.lg.jp Radiocesium (137Cs) derived from Fukushima Dai-ichi Nuclear Power Plant (FDNPP) affected contamination to marine fish species in Fukushima Prefecture. Previous study suggested that 137Cs derived from Chernobyl was transferred to marine ecosystem and food web, and also showed relationships between 137Cs concentration and stable isotopic ratios ( δ  13C and  δ  15N). Although contamination process via food web is considered to be one of the main factors for marine fishes, little is known about this process especially in coastal environment in Fukushima. Here, to reveal the effect of FDNPP accident, 137Cs concentration of seven marine fishes (greenling Hexagrammos otakii, Japanese rockfish Sebastes cheni, Japanese flounder Paralichthys olivaceus, Pacific cod Gadus macrocephalus, marbled sole Pseudopleuronectes yokohamae, slime flounder Microstomus achne, willowy flounder Tanakius kitaharai) caught in Fukushima Prefecture during 2011-2018 were analyzed. Furthermore, to examine the relationship between 137Cs contamination and the feeding habitat of these fishes, we conducted a stable isotopic analysis (  δ  13C and   δ 15N). Based on results obtained from a total of 25032 samples, it is readily apparent that 137Cs concentration of all species have decreased dramatically during 2011-2018 and average 137Cs concentration of each species showed the lowest value (0.25-1.59 Bq/kg) in 2018. We discussed the degreasing trend of 137Cs concentration with fish size and stable isotopic data. Keywords : radiocesium, marine fish
福島県沿岸域における魚類の放射性セシウム蓄積過程の解明
鈴木翔太郎¹、天野洋典*¹、神山亨一¹、和田敏裕¹
'福島県水産海洋研究センター ²福島大学環境放射能研究所*責任著者: yousuke_amano_01@pref.fukushima.lg.jp東京電力福島第一原子力発電所事故による放射性セシウム（137Cs）の海産魚介類への影響を明らかにするため、 2011年から2018年に福島県沿岸域で採集された海産7魚種（アイナメ、シロメバル、ヒラメ、マダラ、マコガレイ、ババガレイ、ヤナギムシガレイ）の137Cs濃度と炭茶・窒茶安定同位体比（以下、CN比）を測定した。 7魚種の137Cs濃度は明示的な低下傾向を示し、2018年に採集された各魚種の平均値は0.25 ～ 1.59 Bq/kgであった。各魚種の137Cs濃度について、全長組成やCN比との関係から福島県沿岸域における魚種ごとの取り込みや低下傾向の違いについて解析を行った。キーワード：放射性セシウム、海産魚類
P-27
Elucidation of the migration ecology of fish around the Fukushima Daiichi Nuclear Power Plant for risk assessment of radioactive
contamination of fish
Takuji Noda* ¹ , Toshihiro Wada ² , Hiromichi Mitamura 3 1 Graduate School of Informatics, Kyoto University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: noda.takuji.7m @kyoto-u.ac.jp Recovery of coastal fisheries in Fukushima Prefecture have been significantly delayed due to the direct damage from the tsunami and the radioactive contamination of marine products after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. One of the problems is that fish exceeding the regulatory limit of radioactive cesium are still inhabited near the FDNPP, and "the movement of fish cannot be controlled". The purpose of this study is to clarify when and how much fish caught in the banned areas (within 5 km radius area) use the coastal waters around the FDNPP, which is a key information for an accurate risk assessment of radioactive contamination of fish. An experiment was conducted with the cooperation of the Soma-Futaba Fishery Cooperative in the Ukedo area of Namie Town, located 5 km north of the FDNPP. From the end of November to the end of December 2018, depth and temperature loggers were installed to a total of 24 flatfishes; 15 Japanese flounders, 7 stone flounders, 1 marbled flounder, and 1 spotted halibut, caught by a stationary net. So far, 4 Japanese flounders and 2 stone flounders have been recaptured, and logger data has been successfully obtained. Currently, we are analyzing the movement trajectory using the obtained data, while measuring the radioactive cesium concentration in the muscles of the recaptured individuals, aiming at analyzing the relationship between the movement paths and the radioactive cesium concentrations. Keywords : bio-logging, fish, migration, radioactive cesium
魚類の放射能汚染のリスク評価に向けた原発周辺海域の魚類の移動生
態の解明
野田琢嗣* ¹、和田敏裕、三田村啓理
¹京都大学大学院情報学研究科
²福島大学環境放射能研究所*責任著者：noda.takuji.7m @kyoto-u.ac.jp福島県の沿岸漁業は、津波による直接的被害に加えて、原発事故に伴う魚介類の放射能汚染の問題により、復旧が著しく遅れている。その理由の一つとして、現在も原発港内には放射性セシウムの基準値を上回る魚類が未だに生息しており、｢魚類の移動を制御することができない｣ことが挙げられる。そこで本研究では、操業禁止エリアで採捕した魚類が、原発周辺の海域をいつどの程度利用しているかを明らかにすることで、魚類の放射能汚染の正確なリスク評価に資する情報を得ることを目的とした。原発から5km北に位置する浪江町請戸地区にて、相馬双葉漁業協同組合の協力を得て実験を行った。2018年11月末–12月末に、底建網で採捕されたヒラメ(15個体)・イシガレイ(7個体)・マコガレイ(1個体)・ホシガレイ(1個体)の合計24個体に深度・温度ロガーを装着し、その場で放流を行った。これまでにヒラメ４個体、イシガレイ２個体が再補され、ロガーのデータ回収に成功した。現在、得られたデータを用いて移動履歴の解析を進めるとともに、再捕個体の筋肉中の放射性セシウム濃度を測定し、移動経路と放射性セシウム濃度の関係の解析を進めている。キーワード：バイオロギング、魚類、移動生態、放射性セシウム
P-28
Relationship between radiocesium concentration and trophic position
of fish in Matsukawa-ura Lagoon, Fukushima Prefecture
Akira Matsumoto* ¹ , Yoshiaki Morioka ¹ , Manabu Yamada ¹ , Toshiyuki Sato ¹ , Toshihiro Wada ² ¹ Fukushima Prefectural Research Institute of Fisheries Resources ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: matsumoto_akira_01@pref.fukushima.lg.jp Matsukawa-Ura Lagoon is a shallow brackish lagoon located in northeastern Fukushima prefecture. The lagoon is nursery ground for various juvenile fish. The objectives of the present study was to elucidate the effect of difference in diet on radiocesium ( 137 Cs) concentration in grey mullet ( Mugil cephalus ) and Japanese seabass ( Lateolabrax japonicus ), which are typical fish species in brackish waters. From July to November 2019, grey mullet (n=15) and Japanese seabass (n=5) were collected using 2-m beam trawl and cast net in northern area of the lagoon. Their total length and body weight were measured. Stomach contents were also observed. The 137 Cs concentration in muscle of each individual was measured using high-purity germanium (HPGe) semiconductor detectors. Prey items of both fish species (mullet: sediments, seabass: mysid) were also collected at the same areas. The 137Cs concentration of prey items were measured as mentioned above. The ranges of both fish species were 0.89–2.07 (grey mullert) and 1.36–2.70 Bq/kg-wet (Japanese seabass), respectively. There was no clear difference. On the other hand, the 137Cs concentration of sediment sample and mysid were 50.0 and 0.98 Bq/kg, respectively. Currently, the accumulation from seawater, rather than food web transfer, may be the main source of 137Cs in fish inhabiting in Matsukawa-Ura Lagoon. Although grey mullet actually fed on sediments, there was little transfer of 137Cs from those sediments. Keywords : grey mullet, Japanese seabass, 137Cs concentration, Matsukawa-Ura Lagoon
福島県松川浦における魚類の放射性セシウム濃度と栄養段階との関係
松本陽* '、守岡良晃'、山田学'、佐藤利幸'、和田敏裕'
¹福島県水産資源研究所²福島大学環境放射能研究所*責任著者：matsumoto_akira_01@pref.fukushima.lg.jp福島県北部にある松川浦は、汽水の閉鎮性潟湖であり、多くの魚種の成育場となっている。本発表では、こうした汽水域の代表種であるポラMugil cephalusおよびスズキLateolabrax japonicusに着目し、137Cs濃度に対する食性の影響を明らかにすることを目的とした。2019年7 ～ 11月の間に、松川浦北部において、ピームトロール網および投網により、ボラ20個体、スズキ5個体を採捕した。体サイズの測定と胃内容物の観察を行った後、個体ごとに筋肉の137Cs濃度を測定した。同地点において、両種の餌（ボラ：堆積物、スズキ：イサザアミNeomysis avatschensis）を徒手採捕し、137Cs濃度を測定した。ポラおよびスズキの137Cs濃度の範囲は、それぞれ0.89–2.07および1.36–2.70 Bq/ kgであり、明瞭な差はなかった。一方、餌である堆積物およびイサザアミの137Cs濃度は、それぞれ50.0および0.98 Bq/kgであった。これらの結果から、現在の松川浦における魚類の137Cs濃度は、食性よりも海水の濃度に依存すると考えられた。また、堆積物に137Csが吸着していても魚類への移行はほぼないことが示された。キーワード：ボラ、スズキ、137Cs濃度、松川浦
P-29
Effect of radiocesium-bearing microparticles from suspended particles
on the solid-water distribution coefficient
Hikaru Miura* ¹ , Takashi Ishimaru ² , Yukari Ito ² , Jota Kanda ² , Yuichi Kurihara ³ , Atsushi Kubo ' , Daisuke Tsumune ¹ , Hirofumi Tazoe ⁵ , Yoshio Takahashi ⁶ ¹ Central Research Institute of Electric Power Industry, ² Tokyo university of marine science and technology, ³ Japan Atomic Energy Agency, 4 Shizuoka university, 5 Hirosaki university, 6 The university of Tokyo *Corresponding author: hi-miura@criepi.denken.or.jp Miura et al. (2018) reported cesium-bearing microparticles (CsMPs) from the suspended particles in river water and their effect on Kd value, which suggested CsMPs may exist in the ocean transported through rivers. Kubo et al. (2018) and Ikenoue et al. (2018) reported hot spots in the ocean samples by autoradiography but they did not separate CsMPs from these spots. In this presentation, we first report CsMPs separated from marine suspended particles, sinking particles, and sediments in coastal area of Fukushima and compare them with CsMPs from the terrestrial samples. We collected suspended particles (2011, 2013, 2015, 2019), sinking particles (2014), sediment cores (2011) from coastal area of Fukushima. By a wet separation method (Miura et al., 2018), we separated CsMPs from these samples. After measurement of radioactivity with a high-purity germanium semiconductor detector, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses were performed for separated CsMPs. Using autoradiography, we calculated 137 Cs activity of unseparated hot spots over 0.1 Bq, which may be CsMPs. We separated 5 CsMPs from marine samples. The results of SEM-EDS analyses showed that these CsMPs have almost similar characteristics to the reported CsMPs because they mainly consist of Si, Cs, Fe, and Zn. Their 134Cs/137Cs showed that the CsMPs were from Unit 2 or 3 of FDNPP. 137Cs radioactivity per volume is also similar to reported CsMPs from Unit 2 or 3. In this presentation, we will show the effect of CsMPs on Kd values. CsMPs in the ocean samples will make apparent Kd values be higher than intrinsic Kd values related to the adsorption-desorption reaction to the clay minerals, which may explain the large variation of Cs concentration in marine samples. Keywords : radiocesium, radiocesium-bearing microparticle, suspended particle from ocean
熊川沖の懸濁粒子中のセシウム合有粒子中のセシウムが固液分配に与
える影響評価
三浦輝* ¹、石丸隆²、伊藤友加里²、神田譲太²、栗原雄一²、久保敦¹、津旨大輔¹、田副博文²、高橋嘉夫° ¹竜力中央研究所、¹東京海洋大学、³日本原子力研究開発機構、‘静岡大学、‘弘前大学、‘東京大学*責任著者: hi-miura@criepi.denken.or.jp Miura et al. (2018)は河川懸濁粒子中から放射性Cs粒子(CsMPs)を発見し、CsMPsが河川を通じて海洋へと移行していることを示唆した。その後、Kubo et al. (2018)、Ikenoue et al. (2018)はオートラジオグラフィーを用いて、海洋サンプル中に放射能が特異的に高い粒子が含まれることを報告したが、粒子の単離や分析は行っていない。本研究では、種々の海洋サンプルから高線量粒子を単離、分析し、陸域由来のCsMPsとの比較を行った。サンプルとして、福島沿岸域で採取された海洋態濁粒子(2011, 2013, 2015, 2019)、海洋沈降粒子(2014)、海洋堆積物(2011)を用いた。湿式分離(Miura et al., 2018)法を用いてCsMPsを計5粒子単離し、放射能測定と電子顕微鏡観察を行った。1粒子あたりの137Cs放射能が0.1 Bqを超えるCsMPsと推測される未分離の高線量粒子についても、オートラジオグラフィーを用いて定量を行った。電子顕微鏡観察の結果、粒子はSi、Cs、Fe、Znなどを含んでおり、既報のCsMPsと同様の元素組成であった。134Cs/137Cs放射能比から、福島第一原発２号機もしくは３号機由来であることが示唆された。粒子の体積あたりの137Cs濃度も既報値に一致した。CsMPsが海洋におけるCsの固液分配係数(Kd)に与える影響についても報告する。キーワード：放射性セシウム、放射性セシウム粒子、海洋懸濁粒子
P-30
Evaluations of water discharge and material transports to coastal ocean via submarine groundwater discharge using radionuclides as chemical
tracers
Saki Katazakai* ¹ , Jing Zhang ² , Tatsuo Aono ³ 1 Graduate School of Science and Engineering, University of Toyama ² Graduate School of Science and Engineering for Research, University of Toyama ³ National Institutes for Quantum and Radiological Science and Technology *Corresponding author: d1872301@ems.u-toyama.ac.jp Submarine Groundwater Discharge (SGD) is one of the processes of water and nutrient transport from the land to the ocean, and it is recognized worldwide that it is important for basic production of the coastal ocean. In Toyama Bay, Submarine Fresh Groundwater Discharge (SFGD) supply a large amount of dissolved nutrients to coastal ocean, which have been indicated to contribute significantly to primary activities on surface ocean (Hatta and Zhang, 2013). However, in recent years, the snowfall decreased in the Hokuriku region including Toyama Prefecture, while the rainfall increased (Japan Meteorological Agency, 2015; Yasunaga and Tomochika, 2017). Considering these climate changes, Zhang et al. (2017) showed that the volume of SGD in Toyama Bay increased by up to 30% in 30 years. The quantitative change of SGD is expected to bring about a qualitative change at the same time. The aims of this study are to understand the changes of water quality associated with climate change, and to evaluate the impact on material supply to the coastal ocean in Toyama Bay. Main conclusions in this study are : (1) Due to the increased rainfall, the residence time of SGD was getting shorter and the dissolved chemical component concentrations were diluted. (2) The fluxes from land to coastal ocean were calculated that the nutrient supply decreased and carbon supply increased. These lead to the reduction in primary activities on surface ocean and further increase CO2 emission into the ocean. Keywords : submarine groundwater discharge (SGD), climate change, nutrient and carbon fluxes
核種を化学トレーサーに用いた海底湧水による沿岸海域への水・
輸送状況の解明
片境紗希* ¹、張勁²、肯野辰雄
1富山大学院理工学教育部²富山大学院理工学研究部²国立研究開発法人量子科学技術研究開発機構　高度被ばく医療センター　福島再生支援研究部*責任著者: d1872301@ems.u-toyama.ac.jp海底地下水湧出（以下、海底湧水）は、陸地から海洋への水と物質輸送プロセスの１つであり、特に、沿岸海洋の一次生産に重要であることが世界中で認識されている。富山湾では淡水性海底湧水が陸起源の栄養塩を沿岸域へ多量に供給しており、これらは沿岸海域の基礎生産に大きく寄与していることが報告されている（Hatta and Zhang, 2013)。しかし近年、富山県を含む北陸地方では降雪量が減少している一方で、降雨量が増加している（気象庁、 2015 ; Yasunaga and Tomochika, 2017)。この気候変化を考慮した水収支モデル計算にて、Zhang et al.(2017)では富山湾沿岸における海底湧水の湧出量が過去30年で最大30%増加したことを示した。海底湧水の量的変化は、同時に賀的変化ももたらすと考えられる。そこで、本研究では気候変化に伴う海底湧水の水賀変化を把握し、現在の富山湾沿岸海洋への物質供給量を評価することを目的とした。本研究の結論は次の通りである：(1)降雨量の増加により、海底湧水の滞留時間の短縮および溶存成分濃度の希釈を確認した。(2)陸から沿岸海洋への物質供給量を計算した結果、栄養塩供給が減少した一方で炭茶供給量が増加したことが明らかとなった。キーワード：海底湧水、気候変化、栄養塩・炭素供給
P-31
Estimate of 137Cs derived from FNPP1 transport amount and time
scale into the Sea of Japan
Yayoi Inomata* ¹ , Michio Aoyama ² ¹ Institute for Nature and Environmental Technology, Kanazawa University ² Center for Research in Isotopes and Environmental Dynamics, Tsukuba University *Corresponding author: E-Mail yinomata@se.kanazawa-u.ac.jp The 137Cs activity concentrations in the SOJ have been increasing since 2012-2013 and reached a maximum in 2015–2016 of approximately 3.4 Bq m-3. The integrated amount of FNPP1-derived 137Cs that entered the SOJ until 2017 estimated to be 0.27 ± 0.02 PBq, 6.4 % of the estimated total amount of FNPP1-derived 137Cs in the STMW. The integrated amount of FNPP1-derived 137Cs that returned to the North Pacific Ocean through the Tsugaru Strait was estimated to be 0.11 ± 0.01 Bq, 42 % of the total amount of FNPP1-derived 137 Cs transported to the SOJ and 2.7 % of the estimated total amount of FNPP1-derived 137 Cs in the STMW. We also estimated the apparent half residence time (Tap) of 137Cs in the surface sea water in the SOJ, ECS, and western North Pacific Ocean (wNPO) between 2000 and 2010. Tap in SOJ, ECS, and wNPO are 18.0yr, 23.5yr, and 17.3 yr, respectively. The longer Tap in SOJ and ECS suggests that 137Cs derived from global fallout may be recirculated into the SOJ through ECS from wNPO. Keywords : 137 Cs, FNPP1, re-circulation into the SOJ
日本海及び北太平洋における福島原子力発電所由来の放射性セシウム
濃度の輸送の時定数と輸送量の推定
猪股弥生* ¹、青山道夫²
¹金沢大学環日本海域環境研究センター ²筑波大学アイソトープ環境動態研究センター *責任著者：yinomata@se.kanazawa-u.ac.jp本研究では、2012 – 2017年に日本海に流入した東京電力福島第１原発事故由来の放射性セシウム(FNPP1-137C s )の時空間変動を解析した。FNPP1-137C  sの濃度は、2012-2013年に増加し、2015-2016年に最大（約3.4Bqm-3）となった。これは、FNPP1事故前の約2倍に相当した。2017年までに、日本海に流入したFNPP1-137Csは0.27 ± 0.02 PBqで、これは亜熱帯表層水に取り込まれたFNPP1-137Csの6.4%に相当していた。さらに、FNPP1事故直前の2000-2010年までの137Csの見かけの半減期は、日本海18年、東シナ海23.5年、北部北太平洋17.3年であった。このことから、大規模核実験で太平洋に注入された137Csも、太平洋から東シナ海を経由して日本海へ再循環している可能性が示唆された。キーワード：放射性セシウム、福島第一原子力発電所、日本海再循環
P-32
Reconstruction of distribution of Fukushima-derived radiocesium in the North Pacific Ocean in 2014 by means of observation and dataset Yuichiro Kumamoto* ¹ , Yasunori Hamajima ² , Michio Aoyama ³ ¹ Japan Agency for Marine-Earth Science and Technology ² Low Level Radioactivity Laboratory, Kanazawa University 3 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: kumamoto@jamstec.go.jp The accident of the Fukushima Dai-ichi Nuclear Power Plant resulted in large amount release of radiocesium (about 40 PBq for 134Cs and 137Cs) into the North Pacific Ocean. The Fukushima-derived radiocesium deposited on and discharged into the north of the Kuroshio Front had been transported eastward along with the North Pacific Current. In summer 2012, about 1.5 years after the accident, relatively higher concentrations (decay-corrected ~10 Bq/m3) were observed in surface water in the central North Pacific Ocean (40-50°N/160°E-170°W). In this study, we measured radiocesium concentration in seawater samples collected during R/V Mirai (Japan Agency for Marine-Earth Science and Technology) cruise MR14-04 in the subarctic area of the North Pacific. Using these new data and a dataset collected published radiocesium data in 2014 from previous studies, we reconstructed distribution of the Fukushima- derived radiocesium in surface water of the North Pacific Ocean in summer 2014, about 3.5 years after the accident. It is found that the high-134Cs water mass (~7 Bq/m3) had been transported further eastward and reached to about 150°W. Keywords : radiocesium, North Pacific Ocean, subarctic area現場観測とデータセット作成による2014年北太平洋全域における福島事故起源放射性セシウムの分布再現熊本雄一郎* ¹、浜島第典²、背山道夫³ ¹海洋研究開発機構²金沢大学環日本海域環境研究センター ³筑波大学アイソトープ環境動態研究センター *責任者: kumamoto@jamstec.go.jp 2011年3月の東京電力福島第一原子力発電所事故により、約40 PBqの放射性セシウム（134Csと137Csの合計）が北太平洋に沈着・流入した。黒潮フロント以北に移行した放射性セシウムは、北太平洋海流に沿って海洋表層を日本近海から東へ運ばれたことが分かっている。事故から約１年半後の2012年夏季の観測データからは、134C濃度が相対的に高い表面海水（事故時に放射壊変補正された濃度～ 10 Bq/m³）が、北緯40 ～ 50度/東経160 ～西経170度の北太平洋中央部で観測された。本研究では、海洋研究開発機構の「みらい」航海MR14-04によって北太平洋亜寒帯域で得られた測定結果と、2014年の北太平洋における観測データ報告値をまとめたデータセットを組み合わせることで、事故後約３年半後の2014年夏季における北太平洋表層海水中の事故起源放射性セシウムの分布を再現した。その結果、高濃度の事故起源134Cs（補正濃度～ 7 Bq/m3）を含む水塊は、西経150度付近までに東に運ばれたことが明らかになった。キーワード：放射性セシウム、北太平洋、亜寒帯域
P-33
Flume experiment for deposition of muddy sediment under waves
Naofumi Yamaguchi* ¹ , Tomohiro Sekiguchi ² , Tetsuya Shinozaki ²
1 Center for Water Environment Studies, Ibaraki University ² Affiliated institutionCenter for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: naofumi.yamaguchi.sci@vc.ibaraki.ac.jp We performed wave-flume experiments in order to examine depositional processes of muddy sediment. In the experiments, we investigated the effect of kind of muddy sediment (bentonite, D50 ~ 13 μ m; silt, D50 ~ 37 μ m) under same condition of wave and initial sand bed. In the present experimental series, either kind of muddy sediment did not deposit on the bed surface under the wave condition which can generate sandy wave ripples. The present result suggests that, it is difficult for even high-concentrated muddy water to deposit on rough bed. Keywords : muddy sediment, wave, sediment dynamics, wave-flume experiment
波浪影響下での泥質堆積物の動態に関する造波水路実験
山口直文* ¹、関口智寛²、篠崎鉄哉²
¹茨城大学広域水圏環境科学教育研究センター
²筑波大学アイソトープ環境動態研究センター
*責任著者: naofumi.yamaguchi.sci@vc.ibaraki.ac.jp沿岸域における放射性物質の動態を考える上で重要となる、波浪が作用する場での泥質堆積物の堆積について調べるため、造波水路を用いた実験を行った。実験では同じ波浪条件および初期のウェーブリップルが発達した砂床で、投入する泥質堆積物の種類（ベントナイト、中央粒径約13 μ m；石英質シルト、中央粒径約37 μ m）を変えて検討を行った。実験の結果、ウェーブリップルが発達しうる強度の波浪下では、いずれの泥質堆積物も底面に堆積しなかった。この結果は、波浪下で粗度のある砂床上には、高濃度の泥質堆積物でも堆積することは難しいことを示唆している。キーワード：泥質堆積物、波浪、堆積物動態、造波水路実験
P-34
Radiocesium-rich microparticles in plankton-net samples off
Fukushima Prefecture
Jota Kanda* ¹ , Yukari Ito ¹ , Takashi Ishimaru ¹ ¹ Tokyo University of Marine Science and Technology *Corresponding author: jkanda@kaiyodai.ac.jp Tokyo University of Marine Science and Technology conducted 13 research cruises off Fukushima Prefecture between July 2011 and May 2017. In each cruise, plankton samples were collected with 100 and 330 μ  m mesh plankton nets for radioactivity determination. During the first voyage, a sample with a Cs-137 concentration of about 1700 Bq kg-1-wet was collected from the surface layer off Shioyazaki, and fine particles with a high radiocesium concentration attached to the fiber-reinforced plastic were found. The Cs-137 concentration in the net samples did not necessarily decrease with time, and in some cases increased sporadically. The relationship between the Cs-137 concentration and the high radiocesium particles detected by the imaging plate revealed that the Cs-137 concentration of the sample reflected the presence of the high cesium particles. Keywords : radiocesium, plankton-net sample, microparticle
福島県沖で採集されたプランクトンサンプル中の高セシウム粒子
神田穣太* '、伊藤友加里'、石丸隆'
¹東京海洋大学
*責任著者: jkanda@kaiyodai.ac.jp東京海洋大学は福島県沖合において2011年7月から2017年5月の間に計13回の研究航海を実施した。各航海において、100および330 μ mメッシュのブランクトンネットによる採集を行い、放射性セシウム濃度を計測した。その結果，初回航海において，塩屋埼沖合表層からCs-137濃度が約1700 Bq kg-1-wetというサンプルを採集し，この中から繊維強化プラスチックに付着したセシウム濃度の高い微小粒子を発見した。ネットサンプルのCs-137濃度は,必ずしも時間とともに低下せず，散発的に高い濃度が見られた。各サンブルのCs-137濃度とイメージングプレートにより検出された高セシウム粒子との関係から、サンプル中のCs-137濃度が高セシウム粒子の存在を反映していることが明らかとなった。キーワード：放射性セシウム、ブランクトンネットサンプル、微小粒子
P-35
Development of biomonitoring method for radionuclides using
mussels
Naoko Murakami-Sugihara ' , Kotaro Shirai* ' , Hirofumi Tazoe ' , Kaoruko Mizukawa ' , Hideshige Takada ' , Takeyasu Yamagata ' , Shigeyoshi Otosaka ' , Hiroshi Ogawa ' 1 Atmosphere and Ocean Research Institute, The University of Tokyo ²  IREM, Hirosaki University ³ Tokyo University of Agriculture and Technology  MALT, The University of Tokyo *Corresponding author: kshirai@aori.u-tokyo.ac.jp Radioactive cesium released into the environment by the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 still remains in the environment. Particularly in coastal areas, continuous release from the FDNPP, inflow of soil and resuspension of sediments containing radioactive cesium requires an efficient monitoring method. In this study, we measured radioactive cesium in mussel mollusk tissue collected from the coastal area of the Tohoku Pacific from 2011 to 2015. As a result, 137 Cs was detected in a wide area from Iwate to Fukushima collected in 2011, but it became below the detection limit in the samples from north of Sendai after 2012. In contrast, 137Cs was detected in many sites in Fukushima Prefecture from 2012 to 2015. In addition, although the 137Cs concentration decreased in many locations with time, the decreasing rate in the 137Cs from the Yotsukura stations was slower than other locations. The fluctuation of 137Cs concentration in the mussel soft tissue seems to reflect the 137Cs composition in suspended particles in seawater, suggesting a significant contribution from inflow of soil and resuspension of marine sediment. Keywords : mussel watch, mytilus, bio-monitoring, 137 Cs
ムラサキイガイを用いた放射性核種のバイオモニタリング手法の開発
杉原奈央子'、白井厚太朗* '、田副博文'、水川薫'、高田秀重'、山形武靖'、乙坂重嘉'、小川浩史' ¹東京大学大気海洋研究所²弘前大学被ばく医療総合研究所²東京農工大学‘東京大学タンデム加速器研究施設*責任著者: kshirai@aori.u-tokyo.ac.jp 2011年3月に発生した福島第一原発の事故によって環境中に放出された放射性セシウムは未だ環境中に残留している。特に沿岸域では，福島第一原発からの継続的な漏洩や，放射性セシウムを吸着した土壌の流入，堆積物の再懸濁が懸念されているため、効率的なモニタリング手法が必要とされている。本研究では、沿岸域の放射性セシウムの時空間変動を把握することを目的として，2011年から2015年に東北太平洋沿岸から採取したイガイ類軟体部中の放射性セシウムを測定した．結果，2011年に採取した試料からは岩手から福島の広い範囲で137Csが検出されたが， 2012年以降仙台以北の地点で検出限界以下であった. それに対して福島県の多くの地点では2012以降2015年に採取した試料まで137Csが検出され続けた．また，事故からの時間経過によって多くの地点では137Cs濃度が低下していったものの、四倉から採取した試料の137Cs濃度は、低下速度が他の地点の試料と比較して遅かった．イガイ軟体部の137Cs濃度の変動は海水中の懸濁態粒子の137Cs濃度を反映していると考えられ、土壌の流入や海底堆積物の再悪濁があったことを示唆している.キーワード：マッセルウォッチ、ムラサキイガイ、バイオモニタリング、137Cs
P-36
Behaviors of analog elements of transuranic nuclides in the sea regions
around Japanese archipelago
Kazuhiro Norisuye* ¹ , Daichi Asanuma ² , Shun Kakuta ² , Tohru Fukazawa ² , Ryo Hashimoto ³ ¹ Faculty of Science, Niigata University ² Graduate School of Science and Technology, Niigata University ³ Graduate School of Science, Hokkaido University *Corresponding author: knorisue@env.sc.niigata-u.ac.jp There has been a dispersion of various contaminants and by-products threatening ecosystem over the Japan Islands and nearby sea regions as a result of increase in human activity and nuclear industry. Individual substances display their own biogeochemical behavior in the marine environment, while they appear to be controlled also by a kind of universe property. Understanding of such properties may contribute to progress in our knowledge of the diffusion and biogeochemical cycles of anthropogenic nuclides released to the environment. We are investigating various elements in the sea regions characterized by unique topography and environmental properties. Here we show our new data and idea on bismuth and lead as an analog of transuranic radionuclides in these sea regions. Keywords : analog elements of transuranic nuclides, bismuth, lead
日本周辺海域における超ウラン核種アナログ元素群の動態
則末和宏* ¹、浅沼大地²、角田隼²、深澤徹²、橋本燎²
¹新潟大学理学部²新潟大学大学院自然科学研究科³北海道大学環境科学院*責任著者: knorisue@env.sc.niigata-u.ac.jp人類活動や核産業の活発化に伴い、国土とその周辺海域に多様な汚染物質や生態系を脅かす副産物が拡散してきた。個々の物質は個々の生物地球化学的性質に起因した環境動態を示す一方で、共通の言わば普遍的特性にも支配されて循環しているようである。この普遍的な特性を把握することは、漏洩した人工放射性核種のグローバル拡散過程の理解に寄与する。そこで、多様な地形的・環境特性をもつ海域を対象として種々の元茶の分布調査の研究を行っている。本研究では超ウラン核種のアナログ元茶であるビスマスと鉛に着目し、日本周辺域における我々の知見を紹介する。キーワード：超ウラン核種アナログ元茶、ビスマス、鉛
P-37
Transport of suspended radiocesium in coastal area off Fukushima
Shigeyoshi Otosaka* ¹ , Takashi Suzuki ² , Tadahiko Tsuruta ² , Toshiharu Misonou ² , Terumi Dohi ² , Yoshihisa Mino ³ , Chiho Sukigara 4 , Yukari Ito 4 , Jota Kanda 4 , Tahashi Ishimaru 4 ¹ Atmosphere and Ocean Research Institute, The University of Tokyo ² Japan Atomic Energy Agency ³ Nagoya University 4 Tokyo University of Marine Science and Technology *Corresponding author: otosaka@aori.u-tokyo.ac.jp A time-series sediment trap was deployed from October 2017 to June 2018 at a station located in southeast of the Fukushima Daiichi Nuclear Power Plant to clarify the transport process of suspended radiocesium from the coast to the offshore area.  Sinking particles of 39 periods were collected by this experiment.  Radiocesium was detected from sinking particles throughout the observation period, and the concentration showed clear seasonal variation. The observed flux of radiocesium showed maxima in winter (December-January) and spring (March-April).  From detailed analysis of physical and chemical characteristics of sinking particles, it was found that sinking particles were composed of biological particles with relatively low degradation in winter and fine-grained terrestrial particles in spring. Especially in spring, high radiocesium flux was observed, and it was presumed due to lateral transport of radiocesium- bound lithogenic particles from the coastal area to the offshore.  However, the effect of redistribution of radiocesium in seabed sediments by this process is considered to be limited. Keywords : radiocesium, sinking particles, seabed sediment
沈降粒子特性の相互比較による陸域-海域間の懸濁態放射性核種の輸送
過程の解明
乙坂重嘉*¹、鈴木崇史'鶴田忠彦' 、御園生敏治' 、土肥輝美' 、三野義尚' 、柄千穂' 、伊藤友加里' 、神穣太' 、石丸隆" ¹東京大学大気海洋研究所²日本原子力研究開発機構²名古屋大学東京海洋大学*責任著者: otosaka@aori.u-tokyo.ac.jp福島沿岸の海底に蓄積した放射性セシウムの移動過程を明らかにするため、福島第一原子力発電所の南南東の陸棚緑辺域において、2017年10月から2018年6月にかけて時系列式セジメントトラップを設置し、計39期間の沈降粒子試料を採取した。沈降粒子からは観測期間を通じて放射性セシウムが検出され、その濃度は明瞭な季節変動を示した。観測された放射性セシウムの粒子束は、冬季（12~1月）と春季（3月~4月）に極大を示した。沈降粒子特性の詳細な分析から、冬季は比較的分解度の低い生物粒子が、春季は陸起源粒子が沈降粒子を構成していることがわかった。特に春季には高い放射性セシウム粒子束が観測され、放射性セシウムを含んだ陸起源粒子が、沿岸域から沖合海域に水平移動したことが、高い粒子束の原因であると推測された。ただし、この過程による、海底堆積物中での放射性セシウムの再分布の効果は限定的であると考えられる。キーワード：放射性セシウム、沈降粒子、海底堆積物
P-38
Study on supply process of radioactive cesium from Uda River /
Matsukawa-ura to the ocean
Daisuke Tsumune* ¹ , Hikaru Miura ¹ , Seiji Hayashi ² , Hideki Tsuji ² , Yasunori Hamajima ³ , Michio Aoyama ³ 1 Central Research Institute of Electric Power Industry ² Fukushima Branch, National Institute for Environmental Studies 3 Institute of Nature and Environmental Technology, Kanazawa University 3 Center for Research in Isotopes and Environmental Dynamics, Tsukuba University *Corresponding author: tsumune@criepi.denken.or.jp Radiocesium deposited on land due to the Fukushima Daiichi Nuclear Power Plant accident, continues to be discharged to the ocean through rivers. It was difficult to detect the effects of river discharge of dissolved radiocesium in the ocean because the effects of direct release from the site were still dominant. The results of the regional ocean model considering direct release were underestimated offshore blackish lake, Matsukawa-Ura. The dissolved radiocesium concentrations in the Uta River and the ocean were almost the same, and those in Matsukawa-Ura were several times higher. In other words, the effect of the supply of dissolved radioactive cesium from Matsukawa-Ura to the ocean was detectable. The bottom sediment of Matsukawa-Ura was contaminated by the impact of high contaminated seawater at the beginning of the accident, and the concentration of dissolved radiocesium in pore water is still high. It is hypothesized that dissolved radioactive cesium in pore water is supplied to Matsukawa-Ura by tide. Water samples were corrected to measure the concentration of dissolved radioactive cesium at the time of rising and falling tides. The results are shown in the poster presentation. Keywords : dissolved radiocesium, Brackish lake, river discharge, direct release, regional ocean model
宇多川・松川浦から海洋への放射性セシウムの供給過程の解明
津旨大輔* '、三浦輝'、林誠二²、辻英樹²、浜島靖典²、青山道夫*
¹一般財団法人電力中央研究所²国立環境研究所福島支部³金沢大学環日本海域環境研究センター ‘筑波大学アイソトープ環境動態研究センター *責任著者：tsumune@criepi.denken.or.jp福島第一原発事故によって陸域へ降下した放射性セシウムは河川を通じて海洋へ供給され続けている。海洋においては、原発敷地から継続している直接編改の影響が支配的であるため、河川供給の影響の検出が困難であった。宇多川と汽水湖である松川浦前面海域において、直接漏洩を考慮した領域海洋モデルの結果は過小評価となっていた。宇多川と海洋の溶存放射性セシウム濃度はほぼ同じで、松川浦の濃度はそれらに比べて数倍高かった。つまり松川浦から海洋への落存放射性セシウムの供給の影響が見られる。松川浦は事故初期の高濃度汚染水の到達の影響によって湖底が汚染されており、間隙水中の溶存放射性セシウム濃度は高い。潮汐によって、間隙水中の溶存放射性セシウムが松川浦に供給されるという仮説が考えられる。松川浦において、潮汐の上げ潮時と下げ潮時に採水を行い、溶存放射性セシウム濃度を測定した。結果は、ポスター発表において示す。キーワード：溶存放射性セシウム、汽水湖、河川供給、直接漏洩、領域海洋モデル
P-39
Preliminary investigation on radiocesium dynamics research using moss
Mamoru Sato* ¹ , Daisuke Takata '
¹ Faculty of Food and agricultural Sciences, Fukushima University *Corresponding author: florpomofores2105-1804@coral.plala.or.jp In order to obtain basic knowledge for quantitatively analyzing the adsorption, leaching and transport of 137Cs in orchards using moss, measurement methods for small samples (Exp.1), period for the regrowth of moss (Exp.2) and the correlation analysis between air dose rate and 137Cs concentration in moss (Exp3) were examined. Exp. 1: Measurement values when volume of moss sample less than 1 g is increased by sphagnum moss for geometry correction (BT) and when moss sample is prepared higher than 2.5 cm by itself (NBT) were compared with the measured value of a moss sample less than 1 g (CONT). A significant proportional equation was obtained between the 137 Cs content in BT and CONT calculated from the measured concentrations, and content in BT was 6.5% higher than that in CONT. On the other hand, the measured concentration of NBT did not show a significant difference from CONT. Exp. 2: On October 24 in 2018, moss was exfoliated in a circular shape with a diameter of 2 cm within five colony of compressed entodon moss [Entodon challengeri (Paris) Card.] on Japanese persimmon tree. On November 29 in the following year, four sites were almost completely regenerated and the remaining one was partially regenerated. Exp. 3: The correlation between 137Cs concentration in moss and air dose rate in the forest of Mt. Ryozen was investigated for four years from 2015. As a result, a significant correlation was observed between the both until 2017, but no correlation was observed in 2018. The ratio of 137Cs concentration in the moss at the same location to the air dose rate was lower of Hypnum plumaeforme Wilson with strong prosperity than that of the other moss species. On the other hand, a significant correlation was found between 137Cs concentration in moss and air dose rate when the survey area is expanded to the forest in Fukushima and Date City in 2019. However, some moss was apparently lower than the regression line. As a result, the method of measuring the concentration of 137Cs in a small amount of moss by increasing volume using sphagnum moss should be effective. It became clear that the long-term survey of 137Cs concentration in moss is required to take the dilution of moss concentration by regrowth for account. Keywords : geometry, period for regrowth of moss, air dose rate
コケを活用した放射性セシウム動態研究に関わる予備的調査
佐藤守* ' 、高田大輔'
¹福島大学農学群食農学類
*責任著者: florpomofores2105-1804@coral.plala.or.jpコケを活用して樹園地の137Csの吸着、溶脱および輸送を定量的に解析する上での基礎的知見を得るため、少量試料の測定法、コケの再生期間および空間線量とコケ中137Cs濃度の関係性について検証した。試験1． U8容器での少量コケの試料調整法の検討：ジオメトリー補正のため1g以下のコケ試料をミズゴケで増量した場合(BT)とコケ試料のみで高さ2.5 cm以上に調整した場合(NBT)の測定価を1g以下のコケ試料の測定価(CONT)と比較した。測定濃度から算出したBTとCONTの137Cs含有量間で有意な比例式が得られBTはCONTより6.5%高かった。これに対し、NBTでの測定濃度はCONTとの有意差は認められなかった。試験2. コケの再生年数の検証：2018年10月24日にカキ経済園の樹上の5か所のヒロハツヤゴケ植生群から直径2cmの円状にコケを剥離し、経過を観察した。翌年11月29日には4か所はほぼ面的に再生し、残る1か所も部分的に再生が確認された。試験3.空間線量とコケ中137Cs濃度の関係性に及ぼす要因の検証：霊山におけるコケ中137Cs濃度と空間線量の関係を2015年から4か年離続調査した。その結果、2017年までは両者間で有意な相関が認められたが、2018年は、相関は認められなかった。同一箇所のコケ中137Cs濃度と空間線量の比は成長力旺盛なハイゴケで他のコケ種より低く経過した。2019年に福島市および伊達市の自然林においてコケ濃度と空間線量の関係を検討した結果、コケ中137Cs濃度と空間線量間で有意な相関が認められたが、1部のコケは同一箇所の他のコケより著しく低い濃度であった。以上の結果、少量のコケ中137Cs濃度の測定はミズゴケで増量する方法が有効であること。コケ中137Cs濃度の長期的な調査にあたっては更新されたコケの濃度希釈を考慮する必要があることが明らかとなった。キーワード：ジオメトリー、コケ再生期間、空間線量率
P-40
Relationships between 137Cs concentration of masu salmon and crucian
carp and indicators for 137Cs contamination in environment at lakes Yuto Funaki* ¹ , Kazuyoshi Takasaki* ² , Wataru Teramoto* ¹ , Tadahiro Sohtome* ¹ ' Fukushima Prefectural Inland Water Fisheries Experimental Station, ² Fukushima Prefecture Fisheries and Marine Science Research Center *Corresponding author: funaki_yuto_01@pref.fukushima.lg.jp In lakes, which had relatively high 137Cs concentration of the surrounding soil, 137Cs concentrations in lake water, zooplanktons, and fish in lakes were known to remain at a high level. 137Cs concentrations in freshwater fish in mountain streams was suggested to be controlled by the transfer of 137Cs to river water from forest organic soil in previous study. In this study, in order to clarify the factors of fish in lakes, the relationship between 137Cs concentration in fishes and indicators for 137Cs contamination around and in lakes was examined. Lake water, zooplankton and fish were collected in 13 dam lakes in Fukushima Prefecture from 2013 to 2018. The concentrations of dissolved 137Cs in lake water and 137Cs in zooplankton and muscle tissue of fish were measured using germanium semiconductor detector. The date analysis was conducted by average annual 137Cs concentrations of specimens, excluding values below detection limit. There were significantly correlations between these three indicators for contamination of 137Cs in environment and 137Cs concentration of both fishes (p <0.001). The results showed a similar tendency between both fishes with different lifespans and food habits. There were significantly positive correlations among three pollution indicators (p<0.05). Keywords : masu salmon, crucian carp, catchment area, air dose rate, zooplankton, 137Cs concentration
湖沼における137Cs汚染指標とヤマメ・フナ類の137Cs濃度の関係
舟木優斗* '、應崎和義* '、寺本航* '、早乙女忠弘* '
'福島県内水面水産試験場²福島県水産海洋研究センター *責任著者: funaki_yuto_01@pref.fukushima.lg.jp周辺域における137Csの土壌沈着量の高い湖沼では、湖水、動物プランクトン、魚類の137Cs濃度が高く推移することが確認されている。また、魚類への137Cs著徴には森林からの移行が関係していることが知られている。そこで本研究では、湖沼の魚類における汚染要因を明らかにするため、福島県内の13のダム湖において、集水域、湖水、動物プランクトンと魚類の137Cs濃度の関係を検討した。2013年から2018年にかけて、福島県内の13のダム湖で、湖水、動物プランクトン、魚類の採集を行い、湖水中の溶存態137Cs、動物プランクトンおよびヤマメとフナの筋肉中の137Cs濃度をゲルマニウム半導体検出器で測定した。なお、湖水と動物プランクトンの137Cs濃度については、各年の平均を用いた。また、検出下限値未満の検体は解析から除いた。137Cs汚染指標は、13のダム湖における2013年から2018年の集水域の空間線量の最大値、湖水に含まれる溶存態137Cs濃度、動物プランクトンの137Cs濃度の３つを用いた。３つの137Cs汚染指標とヤマメ・フナ類の137Cs濃度について相関分析を行った結果、いずれも有意な正の相関が認められた（p < 0.001)。ヤマメとフナ類は食性、寿命が異なるが同様の傾向であった。また、 ３つの汚染指標は相互に有意な正の相関が認められた（p < 0.05)。キーワード：ヤマメ、フナ類、集水域、空間線量、動物プランクトン、137Cs濃度
P-41
Evaluation of vegetation index in Abukuma River basin for estimating
soil erosion
Edea Loa* ¹ , Seiki Kawagoe ² 1 Graduate School of Symbiotic Systems Science and Technology, Fukushima University ²  Faculty of Symbiotic Systems Science, Fukushima University *Corresponding author: s1972008@ipc.fukushima-u.ac.jp Japan's economic activities and population growth since the mid 19th century have contributed to major developments that have resulted in land cover and land-use changes. The country is also prone to several natural disasters which also has a greater impact on land cover and land-use changes. Two of the recent disasters are the Great East Japanese Earth Quake on March 11, 2011 (GEJE2011) and the Typhoon-Hagibis on October, 2019 (Typhoon 201919). These ongoing land-use changes due to natural disasters and other manmade activities have led to land degradation and massive soil erosion, which may have some major environmental concerns especially in vulnerable areas such as hilly terrain areas and the decontaminated areas. Evaluating the land cover is, therefore, an important task that would be able to assist decision-makers in the land and water resource management and planning as well as predicting future disasters. The vegetation index, which is extracted from the Landsat and Sentinel imagery, is often applied to detect the variation in the land surface. The main objective of this paper is to evaluate the land cover changes in the Abukuma River Basin by utilizing the vegetation index to obtain soil erosion. The main reason for setting the Abukuma River Basin as the research basin was that it has a large variation in land cover to GEJE2011 and the recent Typhoon 201919.  The sediment transport changes within the basin could have led to some problems which are of environmental concerns such as riverbed build-up, sea shoreline variation, flooding, etc. The land cover has been evaluated using the Normalized Difference of Vegetation Index (NDVI) by using satellite images. As the evaluation approach, the relationship between long-term scale images and short-term scale images has been compared. Keywords : satellite image analysis, NDVI, land cover, soil erosion, soil protection
阿武隈川流域における土壌侵食推定のための植生指標の評価
イデア　ロア* ¹，川越清樹²
'福島大学大学院共生システム理工学研究科²福島大学共生システム理工学類*責任著者: s1972008@ipc.fukushima-u.ac.jp日本では19世紀半ばからの経済活動および人口増加によって目覚ましい発展が見られ、土地被覆および土地利用が変化した。また、日本では土地被覆および土地利用の変化に影響を与えるような自然災害が発生しやすい。近年発生した2つの災害は2011年3月11日の東日本大震災(GEJE2011)と2019年10月の台風19号(Typhoon 201919)である。人間活動や自然災害によって進行する土地利用の変化は土地荒廃や大規模な土壌侵食につながり、丘陵地や除染地といった脆弱な土地における環境問題を引き起こす可能性がある。したがって、土地被覆を評価することは、土地や水資源の管理・計画に関する意思決定を支援し、将来の災害の予測を可能とするための重要な課題である。 LandsatやSentinelの画像から抽出される植生指標は地表面の変動を検出するためによく使用される。本研究の目的は、阿武隈川流域内の土壌侵食を推定するため、植生指標を用いて土地被覆変化を評価することである。阿武隈川流城を研究対象流域とした理由は、GEJE2011と最近のTyphoon 201919によって流域内の土地被覆が大きく変動したためである。流域内の土砂輸送量の変化は、河道への土砂堆積、海岸線の変動、洪水などの環境問題を引き起こしたと考えられる。土地被覆は衛星画像を用いた正規化植生指標（NDVI）によって評価した。評価を行うにあたり、長期的なスケールの画像と短期的なスケールの画像の関係を比較した。キーワード：衛星画像解析、正規化植生指標、土地被覆、土壌侵食、土壌保護
P-42
Radiocesium concentrations and food habits of Japanese eel in
Fukushima Prefecture
Yushi Fujita* ¹ , Masato Suda ¹ ,Yuma Furuta1,Kenji Watanabe ² ,Shingo Kaneko ¹ ,Kenji Nanba ¹² ,Toshihiro Wada ² 1 Faculty of symbiotic systems science and Technology, Fukushima University, ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: yushi.fujita.j.see.nettle@gmail.com Collecting and shipping restriction measures for Japanese eel (Anguilla japonica) due to the radiocesium ( 134 Cs and 137Cs, hereinafter Cs) contamination after the Fukushima Dai-ichi Nuclear Power Plant accident have continued in several prefectures. In Fukushima Prefecture, the restriction measures have been implemented in the Abukuma River system. However, since few inland waters have been targeted for monitoring, knowledge on eels' Cs contamination is lacking. In this study, we aimed to clarify the Cs concentrations, size-Cs relations, and feeding habits of eels distributed in several rivers in Fukushima Prefecture, including those within the designated evacuation zone. From May 2018 to November 2019, eel samples were collected by electric shockers, fish baskets, scoop net, and Ishikura fishery at 10 sites from 7 rivers in Fukushima Prefecture (Mizuhara, Nikkeshi, Niida, Ohta, Ukedo, Maeda, and Otozawa rivers). In Maeda River with 4 sites, other fishes were also collected. After measurement of total length of the eels, Cs concentrations in muscle tissues were measured using germanium semiconductor detectors. Stomach contents were identified to the lowest possible taxonomic levels. A total of 150 individual eels (Total length 420–730 mm) with various sizes were collected. The maximum and minimum Cs concentrations of eels were respectively 6100 Bq/kg in Otozawa River and 3.19 Bq/kg in Nikkeshi River. Cs concentrations of eels were significantly higher than those of other fish species (temperate bass) in brackish water habitats of Maeda River. Correlation between total length and 137Cs concentration (termed "size effect" ) was observed. The main stomach contents of the eels in Maeda River were small fish, but crabs and terrestrial insects were also observed in the freshwater habitat. Keywords : Anguilla japonica, radiocesium, Fukushima Dai-ichi Nuclear Power Plant, stomach contents
福島県におけるニホンウナギの放射性セシウム濃度と食性
藤田優志* ¹、須田真人¹、古田悠真¹、渡邉恵司¹、兼子伸吾¹、難波謙二¹ ²、和田敏裕²
'福島大学大学院共生システム理工学研究科
²福島大学環境放射能研究所*責任著者: yushi.fujita.j.see.nettle@gmail.com原発事故に伴う放射性セシウム（134Csおよび137Cs、以下Cs）汚染の影響により、複数の県においてニホンウナギ（Anguilla japonica、以下ウナギ）の出荷制限措置が続いている。福島県では阿武隈川水系において出荷制限が設定されているが、県内でモニタリングが実施された水域は少なく、ウナギのCs汚染に関する知見が不足している。本研究では避難指示区域内を含む福島県の複数の河川におけるウナギのCs濃度、及びサイズや食性とCs濃度の関係を明らかにすることを目的とした。 2018年5月から2019年11月にかけて福島県の水原川、日下石川、新田川、太田川、請戸川、前田川（4地点）、および夫沢川の計7河川10地点において、石倉カゴ、アナゴモンドリ、電気ショッカー、及びたも網でウナギを採集した。前田川では他の魚類も採集した。ウナギの全長等を測定後、筋肉中に含まれるCs濃度をゲルマニウム半導体検出器で測定した。また、胃内容物を可能な限り下位のレベルまで同定した。合計150個体の様々なサイズのウナギ（全長420~730 mm）が得られた。ウナギのCs濃度の最大値は夫沢川の6100 Bq/kgであり、最小値は日下石川の3.19 Bq/kgであった。Cs濃度は地点間の差異が非常に大きく、太田川以南の4河川で基準値（100 Bq/kg）を上回る検体が確認された。前田川の汽水域と淡水域においてウナギのCs濃度は他魚種（スズキ）よりも有意に高く、かつ、全長と137Cs濃度の相関関係（サイズ効果）が認められた。前田川の汽水域と淡水域におけるウナギの主な胃内容物は小型魚類であったが、淡水域ではカニ類や陸生昆虫類も確認された。キーワード：ニホンウナギ、放射性セシウム、福島第一原発、胃内容物
P-43
Cs-137 uptake and excretion of Japanese dace under different salinity
conditions using litter-derived Cs-137 containing water
Naoto Kanagawa  ¹ , Keiichi Sasaki ² , Toshihiro Wada* ³ , Kenji Nanba ³ ¹ Faculty of Symbiotic Systems Science and Technology, Fukushima University, ² Fukushima Prefecture Inland Water Fisheries Experimental Station, 3 Institute of Environmental Radioactivity, Fukushima University *Corresponding author : t-wada@ipc.fukushima-u.ac.jp Monitoring results by Fukushima Prefecture showed that a part of freshwater fish samples still exceeded the Japanese regulatory limit of radiocesium (100 Bq/kg-wet), whereas no sample of marine fish has exceeded the regulatory limit since April 2015. There results suggest that radiocesium contamination is more persistent in freshwater fish. High physiological ability to retain cesium during osmoregulation may be one of the factors that can explain the persistent trend in freshwater fish. In this study, we compared the uptake and excretion of Cs-137 in Japanese dace between freshwater and a salinity condition above the iso-osmolarity. In the uptake experiment, uncontaminated dace was reared for 84 days in water adjusted to 0 and 16 psu that contained litter-derived Cs-137 (mean 10.1 and 21.4 Bq/L, respectively). In the excretion experiment, dace were first reared under water containing litter-derived Cs-137 (mean 33.1 Bq/L) for 14 days, and then they were reared under uncontaminated water adjusted to 0 and 16 psu for 56 days. Concentration ratio (CR, unit L/kg) of Cs-137 in water and dace was used to evaluate the Cs-137 uptake. In the uptake experiment, CR values were higher in 16 psu group from day 21 onward. Limiting values estimated from a model (CRt=a(1-e-bt)) were higher in 16 psu group (a: 15.8) than in 0 psu group (4.01). In the excretion experiment, excretion rates were faster in 16 psu group, resulting in the effective biological half-life of 172 days under 0 psu and 59 days under 16 psu conditions. From our results, it is proved that both uptake and excretion rates of Cs-137 are faster in dace under hyper-osmotic conditions. Keywords : dace, body fluid osmotic pressure, Opsu, 16psu, rearing test
リター由来Cs-137含有水を用いた異なる塩分環境下における
ウグイのCs-137の取込と排出
金川尚人'、佐々木恵一²、和田敏裕* '、難波謙二'
¹福島大学共生システム理工学類、¹福島県内水面水産試験場、¹福島大学環境放射能研究所*責任著者: t-wada@ipc.fukushima-u.ac.jp福島県の淡水魚では未だに放射性セシウムの基準値100 Bq/kg-wetを超える検体が散見されている。他方、海水魚の県のモニタニングでは2015年4月以降全ての検体で基準値を下回っている。そのため、淡水魚は海水魚と比較して放射性セシウム汚染の長期化が懸念されている。要因の一つとして浸透圧調節などの生理特性により淡水魚の方が放射性セシウムを排出しにくいことが考えられる。本研究では、ウグイを淡水および体液浸透圧よりも高い塩分条件下で飼育し、飼育水からのCs-137の取込と排出の違いを比較した。取込試験では塩分0、16 psuに調整したリター由来Cs-137含有水（各平均10.1 Bq/L、21.4 Bq/L）で84日間非汚染のウグイを飼育した。排出試験では、14日間Cs-137含有水(平均33.1 Bq/L)で飼育したウグイを塩分0、16 psuに調整した非汚染の水槽に移し、56日間飼育した。飼育水からウグイへのCs-137取込は、ウグイに対する飼育水のCs-137濃度の比（concentration ratio: CR、単位L/ kg）により評価した。取込試験では、0 psu区に比べ16 psu区で21日目以降、CR値が高い結果となった。CRt=a(1-e-bt)をモデル式とし、極限値aを求めると0 psu区で4.01、16 psu区で15.8となった。排出試験では、0 psu区に比べ16 psu区でCs- 137濃度の低下が速く、実効生物学的半減期は0 psu区で172日、16 psu区では59日と推定された。以上の結果から、体液浸透圧よりも高い塩分条件下では、ウグイのCs-137の取込も排出も速いことが実証された。キーワード：ウグイ、体液浸透圧、Opsu、16psu、飼育試験
P-44
Accumulation of radiocaesium in bryophytes
Chieko Otsuki ¹ , Hirofumi Tsukada* ² 1 Graduate School of Symbiotic Systems Science, Fukushima University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: hirot@ipc.fukushima-u.ac.jp Radiocaesium released from the 2011 accident was widely deposited in the environment. Contamination of radiocaesium in higher plants derives by root uptake, and activity concentration of radiocaesium is rapidly decreasing. However, it is reported that 137Cs activity concentration in bryophytes, which is similar to lichen and mushroom, is still higher values. The bryophytes are non-vascular and poikilohydric plants which nutrients can   take from the surface. Bryophytes are widely distributed throughout Japan and it is known as an indicator organism of contamination monitoring material of heavy metals and organic pollutants. In this study, samples were collected from Fukushima and Aomori, Nagasaki prefectures, and accumulation of radiocaesium in bryophytes after the 2011 accident was investigated. The collected bryophyte samples were repeatedly washed until turbidity disappeared, and dried at 70 membrane filter with a pore size of 0.45 μm, and the filtered particles such as soil were dried at 50 ° C for 48 hours. The filtrate was concentrated by adding nitric acid. Each measurement samples were placed in a U-8 container, and 137Cs were quantified with a Ge semiconductor detector. The amount of 137Cs eluted in the bryophyte samples wash water were less than 1% of 137Cs in samples. The amount of 137Cs in particles attached to bryophyte samples were 1.8 to 4.4 times that of 137Cs in samples, confirming the importance of particle removal. The concentration of 137Cs in samples collected in Fukushima prefecture was 0.387-61.7 Bq g-1 dry matter (0.046-10 kBq m-2), which were smaller than the inventory in soil.    After measuring the 137Cs of the collected bryophytes and soils, a map of bryophyte concentration in samples collected in various parts of Japan was created, and the relationship between air dose rate and inventory was analyzed. This study is planning to conduct research on the incorporation of radiocaesium into bryophytes by cultivation tests. Keywords : bryophytes, radioactivity concentration, accumulation status.
薛苔類への放射性セシウムの蓄積
大槻知恵子'、塚田祥文* ² ¹福島大学大学院共生システム理工学研究科²福島大学環境放射能研究所*責任著者: hirot@ipc.fukushima-u.ac.jp 2011年の事故によって放出された放射性セシウムによって、広く環境を汚染した。事故から９年が経過し、一般的な高等植物では土壌からの放射性セシウムの移行が主な経路であり、植物中濃度は急激に減少している。しかしながら、鮮苔類は、地衣類やキノコ類と同様に放射性セシウム濃度の高いことが指摘されている。鮮苔類は非維管束植物で変含水性あり、体表から栄養茶などを取り込む。また、全国に広く分布し、環境における重金属や有機物汚染の指標生物として用いられている。本研究では、福島県、青森県、長崎県で蘇苦類を採取し、2011年の事故後における蘇苦類の放射性セシウムの蓄積状況を調査した。採取した蘚苔類は、濁りが無くなるまで繰り返し洗浄し、70℃で48時間乾燥した。洗浄水は、孔径0.45 μmのメンブランフィルターでろ過し、ろ過した土等の粒子は50℃で48時間乾燥した。ろ液は、硝酸を加えて蒸発遺縮した。それぞれの測定試料はU-8容器に入れ、Ge半導体検出器で137Csを定量した。洗浄水に溶出した137Csは、鮮苦類中137Csの1 %以下であった。鮮苦類に付着していた粒子中137Csは、鮮苦類中137Csの1.8 ～ 4.4倍であった。福島県内で採取した蘚苔類中137Cs濃度は、0.387 ～ 61.7 Bq g-1乾物（0.046 ～ 10 kBq m-2）であり、土壌へのインペントリーに比べ小さい値であった。今後は、試料の検体数を増やし蘇苔類中濃度マップを作成し、空間線量率やインペントリー等との関係を解析すると供に、栽培試験による鮮苔類への放射性セシウムの取り込みについて研究を進める予定である。キーワード：辞苔類放射能濃度著養状況
P-46
Effect of the formation of the micro-terracetts on the Cs-137 and sediment transport on sandy granitic soil in Yamakiya decontaminated hillslopes Yuichi Onda* ¹ , Yoshifumi Wakiyama ² , Syohei Kozuka ' 1 Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: onda@geoenv.tsukuba.ac.jp To study the activity concentration of eroded soil, we focused on the step-like erosion and deposition and discuss the step-like erosion and deposition process. Our study was conducted in Yamakiya USLE soil erosion plot (5 m wide and 21 m long), Fukushima, Japan. This area was decontaminated in 2014 by Ministry of Environment to reduce the air dose rate by removing topsoil and overlaying decomposed granite soil (organic matter: 4.6%, sand: 68.8%, silt: 19.7%, clay: 6.9%,). The topography in the plot was measured by UAV-SfM method. UAV used in this study was Phantom4 Pro and flying height was 5 – 10 m. 200 – 400 photos were taken for each survey. Photos were imported to Photoscan, and 3D point clouds were reconstructed. 3D point clouds were imported to ArcGIS pro and converted to DSM data. Finally, soil surface changes were calculated for each survey period. Transport distances of soil particles were measured by RFID tags. RFID tags were coated with cement, bronze powder, fluorescent paint and topcoat and had 3 – 5 mm size and 2.0 – 3.0 g cm-3 density. 100 RFID tags were set to the soil surface.  Step-like erosion and deposition were observed between 8/28/2019 – 10/16/2019. Soil surface change in this period showed that erosion and deposition were repeated and higher erosion on the lower slope position. Topography data also showed steeper step structures in the eroded area than the depositional area. Median transport distance of RFID tags in interrill areas is 4.1 cm, and 76 cm in terracett areas. Therefore, we found the effect of soil mounds and terracettes on the bare soil connectivity significantly increase the sediment connectivity and sediment transport distance, affecting high activity concentration of Radiocesium from eroded sediment. Keywords : soil erosion, Cs-137, decontamination
山木屋における除染された斜面における放射性物質の移行観測
恩田裕一* ¹、脇山義史²、小塚翔平¹
'筑波大学アイソトープ環境動態研究センター ²福島大学環境放射能研究所*責任著者：onda@geoenv.tsukuba.ac.jp除染された土壌のからの放射能物質濃度を調査するために山木屋USLE土壌侵食プロット（幅５m、長さ21 m）トにおいて研究を行った。研究サイトは日本の福島県山木屋地区にあり、2014年に環境省によって除染され、表土を除去し、花崗岩の真砂土により土壌を被覆することにより、空間線量率の低減をはかったものである（有機物：4.6%、砂：68.8%、シルト：19.7%、粘土：6.9%)。ブロット内の微小地形は、UAV-SfM法によって測定した。この研究で使用したUAVはPhantom4 Proで、飛行高度は5 ～ 10 m、各調査で200 ～ 400枚の写真の撮影を行った。写真は、 Photoscanにインポートし、3D点群がを構築した後、ArcGIS proにインポートされ、DSMデータに変換することによって、調査期間ごとに土壌表面の変化が計算した。土壌粒子の輸送距離は、RFIDタグによって測定した。 RFIDタグは、セメント、背銅粉、蛍光塗料、トップコートでコーティングされ、サイズは３～５mm、密度は2.0 ～ 3.0 g cm-3である。 100個のRFIDタグが土壌表面に設置し、その変化を測量した。 2019年8月28日から2019年10月16日の間に、階段状の侵食と堆積が観察された。この期間の土壌表面の変化は、侵食と堆積が繰り返され、より低い斜面位置でより高い侵食を示した。地形データは、堆積領域よりも侵食領域のより急なステップ構造も示した。インターリル領域でのRFIDタグの輸送距離の中央値は4.1 cmであり、テラセット地形を有する領域では76 cmとなった。これらのことから、除染後の砂質土を表層に敷いた場合、堆積物の接続性と堆積物の輸送距離を大幅に増加させることがわかった。またこのことは、侵食された堆積物からの放射性セシウムが高い値を示すことに影響することが推察される。キーワード：土壌侵食、除染、Cs-137
P-45
Strong contrast of cesium radioactivity between marine and freshwater
fish in Fukushima
Toshihiro Wada* ¹ , Alexei Konoplev ¹ , Yoshifumi Wakiyama ¹ , Kenji Watanabe ¹ , Yuma Furuta ² , Daigo Morishita ³ , Gyo Kawata 4 , Kenji Nanba 12 1 Institute of Environmental Radioactivity, Fukushima University ²  Faculty of Symbiotic System Science, Fukushima University ³ Fukushima Prefectural Fisheries and Marine Science Research Centre 4 Fukushima Prefectural Research Institute of Fisheries Resources *Corresponding author: t-wada@ipc.fukushima-u.ac.jp This study was conducted to present a direct comparison of radiocesium (134Cs and 137Cs) concentrations in marine and freshwater fish inhabiting different water bodies in Fukushima Prefecture (coastal waters, 6.3–54.5 km from the plant; forest rivers and irrigation ponds, 1.4–71.6 km), and to reveal plausible contamination mechanisms for each habitat. In contrast to marine demersal fish (7 species, n = 50), which showed lower and less variable radiocesium concentrations (0.234–3.41 Bq kg − 1-wet), freshwater fish (6 species, n = 463) showed higher and more site-specific variations for each species and habitat (4.09–25600 Bq kg – 1-wet) in 2015–2016. The apparent concentration ratio (aCR, L/kg) of 137Cs in fish to water is higher for fish of freshwater habitats (mean 1240-12900 for each site) than in those of coastal waters (mean 200). Radiocesium contamination is more severe and persistent in freshwater fish, especially those distributed within the designated evacuation zone (salmonids in rivers and bass in ponds). Continuous radiocesium uptake through the food web in relation to fish feeding habits and size (size effect), and biotic/abiotic characteristics in water and surrounding environments are main factors affecting site/habitat-specific bioaccumulation of radiocesium in freshwater fish. By contrast, uniformly lower radiocesium concentrations in marine demersal fish are mainly attributable to decreased radiocesium transfer intensity from the benthic food web because of lowered radiocesium contamination in sediments, and low physiological ability to retain radiocesium. Our results revealed a strong contrast of radiocesium contamination levels and mechanisms between marine and freshwater fish in natural habitats. Keywords : Fukushima, designated evacuation zone, marine and freshwater fish, radiocesium contamination
福島県に生息する海水魚および淡水魚における放射性セシウム濃度の明
確な違い
和田敏裕*¹、アレクセイコノプリョフ¹、脇山義史¹、渡邉憲司¹、古田悠真²、森下大悟²、川田暁¹、難波謙二¹² ¹福島大学環境放射能研究所²福島大学共生システム理工学類³福島県水産海洋研究センター ‘福島県水産資源研究所*責任著者: t-wada@ipc.fukushima-u.ac.jp本研究の目的は、福島県の複数の水域（海域：福島第一原発から6.3–54.5 km、渓流域およびため池：1.4–71.6 km）に生息する海水魚と淡水魚の放射性セシウム（134Csおよび137Cs、以下Cs）濃度を比較するとともに、それらの汚染メカニズムを明らかにすることである。2015–2016年に採集された沿岸底魚類のCs濃度は一様に低い一方(0.2340–3.41 Bq/kg-wet)、淡水魚では地点ごと、魚種ごとに大きな違いが認められた（4.09–25600 Bq/kg-wet)。環境水に対する魚体の137Csの濃度比（CR、L/kg）は、沿岸底魚類（平均200）に比べて、淡水魚類（1240–12900）で高かった。淡水魚のCs汚染は、特に帰還困難区域に生息する魚類（サケ科やバス）で収束しておらず、影響が長期化すると考えられた。淡水魚のCs汚染をもたらす主な要因として、各魚種の食性やサイズに応じた餌生物を介したCsの取込、および周辺域を含めた各水域の生物・非生物環境が考えられた。一方、海水魚のCs濃度が低下した理由としては、海底土のCs濃度の低下に伴う底生食物連鎖を通じたCsの取込の減少やCsをためにくい生理学的な特性が考えらえた。我々の結果から、海水魚および淡水魚におけるCs濃度と汚染メカニズムの明確な違いが明らかにされた。キーワード：福島、帰還困難区域、海水魚と淡水魚、放射性セシウム汚染
P-47
Temporal change of radiocesium leaching from forest canopies following
the Fukushima Daiichi Nuclear Power Plant accident
Hiroaki Kato* ¹ , Tomoki Shinozuka ² , Zul Hilmi Saidin ² , Hikaru Iida ³ , Satoru Akaiwa ² , Yuichi Onda ¹ , Vasyl Yoschenko 4 1 Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ² Graduate School of Life and Environmental Sciences, University of Tsukuba ³  College of Geoscience, University of Tsukuba 4 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: kato.hiroaki.ka@u.tsukuba.ac.jp This study investigated the leaching of canopy-intercepted radiocesium by rainwater and the formation mechanism of its concentration in the cedar forest stand in Namie town, Fukushima prefecture. Using rainwater samplers installed inside and outside of the forest, throughfall (6 samplers), stemflow (3 samplers), and incident open rainfall (3 samplers) were collected, and the cesium-137 concentration were quantified. The throughfall amount was correlated with the canopy openness, locations with the lower canopy density tended to accumulated greater amount rainwater. The cesium-137 concentration in throughfall particularly in particulate form decreased by delusion with increasing event rainfall. On the other hand, the ratio of dissolved cesium-137 in throughfall tended to increase with increasing rainfall. The stemflow showed higher cesium-137 concentration compared to throughfall. The cesium-137 in stemflow was mostly in dissolved form. The permeation flux of water and dissolved cesium-137 into soil by infiltration water showed higher values nearby the basal area of tree stem. These results suggested that the continuous deposition input by throughfall and stemflow increases the heterogeneity of radiocesium at forest floor over time. Keywords : Fukushima accident, forest, throughfall, stemflow, radiocesium, leaching
福島第一原子力発電所事故後の森林樹冠からリーチングされる放射性セ
シウムの時間変化の解明
加藤弘充*¹、篠塚友輝、飯田光³、ズルサイディン²、赤岩哲²、恩田裕一¹、ヴァシルヨシェンコー ¹筑波大学アイソトープ環境動態研究センター ²筑波大学大学院生命環境科学研究科³筑波大学生命環境学群地球学類‘福島大学環境放射能研究所*責任著者: kato.hiroaki.ka@u.tsukuba.ac.jp本研究では、福島県浪江町のスギ林を調査対象として、樹冠中の放射性セシウムの雨水によるリーチングとその濃度の形成機構について調査を実施した。林内外に設置した雨水サンプラーを用いて、樹冠通過雨（12箇所）、樹幹流（6箇所）及び林外雨（3箇所）を採取し、雨量とセシウム137濃度を定量した。樹冠通過雨量は上部の開空度の間に相関が認められ、樹冠密度が低い地点ほど樹冠通過雨量が多いことが分かった。樹冠通過雨に含まれるセシウム137演度は、雨量の増加とともに低下する傾向が認められ、特に懸濁態セシウム137濃度が希釈効果により低減することが示唆された。一方で、樹冠通過雨中の溶存態セシウム137の割合は、雨量の増加とともに上昇する傾向が認められた。樹幹流は、樹冠通過雨と比較して高いセシウム137濃度を示し、大部分が溶存態であることが分かった。土壌浸透水による水及びセシウム137の浸透フラックスは、ともに樹幹周辺のほうが大きい値を示した。以上の事から、樹冠通過雨や樹幹流の影響により、林床の放射性セシウムの偏在性が時間とともに増大する可能性が示唆された。キーワード：福島原発事故、森林、樹冠通過雨、樹幹流、放射性セシウム、リーチング
P-48
Estimation of downward migration of radiocesium in forest soils
using zero-tension lysimeter
Junko Takahashi* ¹ , Takuya Sasaki ¹ , Daichi Hihara ¹ , Yuichi Onda ¹ , Hirofumi Tsukada ²
' Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: takahashi.junko.ka@u.tsukuba.ac.jp There are many reports about estimation of downward migration of radiocesium using model based on the changes in vertical distribution of radiocesium in soil. However, the measured values of the amount of downward migration such as soluble radiocesium in saturation water are limited. Therefore, in the present study, we collected the saturation water under litter, 10 cm and 20 cm depth of soil layers using zero-tension lysimeter and evaluated the contribution rate of the saturation water to the estimated amount of downward migration based on the changes in vertical distribution of radiocesium in soils where we have monitored from 2011. Study sites are Mixed Forest (MF), Mature Cedar Forest (MC) and Young Cedar Forest (YC) in Yamakiya district, Kawamata town, and the estimated deposition density is 450 kBq/m². Zero-tension lysimeters were installed under litter, 10 cm and 20 cm depth of soil layers in each site, and the saturation water samples were collected every one or two months. The collected water samples were filtered by 0.2 μ  m membrane filter and Cs-137 concentration were measured using Ge-semiconductor detector. The Cs-137 concentrations in the saturation water under litter layer are YC site (0.3-5.6 Bq/L) > MF site (0.6-3.9 Bq/L) > MC site (0.06-1.9 Bq/L) in descending order, and larger in summer than in winter. Those under 10 cm and 20 cm depth of soil layers are significantly smaller than those under litter layer, but not significantly different between each other. The collection efficiency of the saturation water by zero-tension lysimeter depends on the catchment area, therefore the underestimated volume of the water samples were corrected. As results, the contribution rate of the saturation water to the estimated amount of downward migration were estimated to be less than 10% under litter layer and more than 50% under 10cm and 20cm depth of soil layers. Keywords : vertical distribution of radiocesium, forest soil, tension-free lysimeter
ゼロテンションライシメータを用いた土壌中放射性セシウムの
下方移行量の評価
高橋純子* ¹、佐々木拓哉¹、日原大智¹、恩田裕一¹、塚田祥文² '筑波大学アイソトープ環境動態研究センター ²福島大学環境放射能研究所*責任著者: takahashi.junko.ka@u.tsukuba.ac.jp従来、土壌中の放射性セシウムの下方移行量は、その深度分布変化に基づくモデルから推定されたものが多く、実測に基づく評価は限られている。そこで、本研究ではこれまでに放射性セシウムの深度分布モニタリングを実施してきた森林３地点において、ゼロテンションライシメータにより定期的にリター浸透水および土壌浸透水を採取し、降雨とともに下方移行している放射性セシウム量を実測するとともに、深度分布の変化から推定される下方移行量に占める浸透水の寄与率を評価することを目的とした。調査地として川俣町山木屋地区のスギ壮齢林、スギ若齢林および混交林（初期沈着量約450kBq/m2）を選定し、リター直下、10cm深、20cm深にゼロテンションライシメータを設置した。1-2ヶ月に一度の浸透水採取を行い、採取試料は0.2 μ mフィルターでろ過した後、Ge半導体検出器を用いてCs-137濃度を測定した。リター直下の浸透水中Cs-137濃度は若齢林(0.3-5.6 Bq/L) >混交林(0.6-3.9 Bq/L) >壮齢林(0.06-1.9 Bq/L)の順に高く、また夏に高く冬に低くなる傾向が認められた。10cm深と20cm深の浸透水中Cs-137濃度については、リター直下のものよりは有意に低かったものの、両者に有意な差は認められなかった。ゼロテンションライシメータによる浸透水の採水量はその集水面積に大きく影響を受けることが知られている。そのため、浸透水量の補正を行ったところ、浸透水による下方移行の寄与率はリターから土壌表層では10%以下であるのに対し、土壌中では50%以上と推定された。キーワード：放射性セシウムの深度分布、森林土壌、テンションフリーライシメータ
P-49
Mutation rate evaluation using microsatellite marker
Shingo Kaneko* ¹.² , Yuta Murayama ¹ , Yoshito Watanabe ³ 1 Faculty of Symbiotic Systems Science and Technology, Fukushima University ² Institution of Environmental Radioactivity, Fukushima University ³ National Institutes for Quantum and Radiological Science and Technology *Corresponding author: kaneko.shingo@gmail.com Few studies have reported on the genetic effects such as nucleotide sequence mutations by chronic exposure of low dose rates. In this study, we tried to measure the mutation rate of Japanese red pine growing in evacuation zone in Fukushima Prefecture using female gametophytes, which are haploids derived from maternal germ cells. The seeds (female gametophytes) were collected from the Japanese red pine growing in Okuma Town (about 4 -7 μ  Gy / h). Genotypes of female gametophyte were determined for 9 microsatellite loci. So far 484 samples (4270 site) have been genotyped and no mutations have been identified. To measure the mutation rate, it is expected that a total of 10,000 or more data is required in terms of the number of samples and loci. However, it can be achieved by using female gametophytes due to the low cost for collecting large number of samples. Keywords : chronic exposure of low dose rates, microsatellite marker, mutation rate
照射実験個体を対象とした塩基配列突然変異の検出法の開発
ーマイクロサテライトマーカーによる突然変異率評価
兼子伸吾* ¹²、村山悠太¹、渡辺嘉人² ¹福島大学共生システム理工学類²福島大学環境放射能研究所³量子科学技術研究開発機構*責任著者: kaneko.shingo@gmail.com毎時数マイクロシーベルト以下の低線量率を長期に被ばくした際の塩基配列突然変異等の遺伝的影響について報告した研究は少ない。そこで本研究では、母親の生殖細胞由来の半数体である針葉樹の離性配偶体を用いて、福島県内の帰還困難区域に生育するアカマツを対象に、突然変異率の実潤を試みた。福島県大熊町内の調査地（約４ μ Gy/h）に生育するアカマツから、母樹の葉および種子（離性配偶体）を採取しDNAを抽出した。マイクロサテライトマーカー 9遺伝子座を用いて雌性配偶体の遺伝子型を決定した。これまでに484サンプルについて遺伝子型を決定したが、突然変異は確認されなかった。突然変異率の実測のためには、サンプル数と遺伝子座数でのベ１万以上のデータ量が必要と予想されるものの、サンプル収集が容易な離性配偶体の解析であれば、十分達成可能であると考えられる。キーワード：マイクロサテライトマーカー、長期低線量被ばく、突然変異率
P-50
Analysis of genetic changes in cancer induced by low dose rate radiation -Time course-dependent analysis of chromosomal abnormalities in hematopoietic tissues of irradiated mice- Kodai Suga 12 , Ikue Asari 1 , Masato Umetsu ² , Yuma Imai ² , Yohei Fujishima 3.4 , Valerie Swee Ting Goh ³ , Naomi Sasaki ' , Kentaro Ariyoshi 1.5 , Tomisato Miura 2.3 , Yutaka Yamada ' , Mitsuaki Yoshida* ' ' Institute of Radiation Emergency Medicine, Hirosaki University, ² School of Health Science, Hirosaki University ³  Graduate School Health Sciences, Hirosaki University ' School of Medicine, Tohoku University, ' Fukushima Medical University 6 Quantum and Radiological Science and Technology *Corresponding author: myoshida@hiroskai-u.ac.jp Epidemiological analysis of atomic bomb survivors has indicated that the frequency of hematopoietic tumors increases several years after the bombing. In this study, we analyzed temporal changes of chromosomal abnormalities in hematopoietic tissues from irradiated mice as a preliminary experiment. Also, we compared the chromosome abnormalities between the two mice strains using radiation-sensitive mice (C3H) and radiation-resistant mice (B6). Eight-week-old C57BL / 6NJcl mice and C3H / HeJJcl mice were irradiated with 4 Gy (1 Gy / min) X-rays, and at 1, 2, 3 and 6 months after irradiation, chromosomes from hematopoietic tissues (bone marrow, spleen, blood) were prepared and were analyzed by Hoechst-quinacrine double staining. The frequency of chromosome abnormalities was high even at 6 months after irradiation in both strains. Although the chromosome involved in the abnormality was relatively random in C3H, specific chromosomes (chromosomes 1, 8, 10, 11, 12, 13, and 15) tended to have a high abnormality frequency in B6. In addition, clonal abnormalities common to bone marrow, peripheral blood, and spleen were confirmed in some individuals. These results suggest that various chromosomal abnormalities are induced by irradiation, but that cells with superior proliferative ability may expand clonally over time and become malignant. In the future, the trend of chromosomal abnormalities after 6 months or more after irradiation will be noted. Based on these results, we would like to analyze the effects of low dose rate radiation in the future. Keywords : radiation exposure, chromosome abnormality, time course dependent analysis, hematopoietic tissue
低線量率放射線により誘発された癌の遺伝学的変化の解析
-放射線照射したマウスの造血系組織における染色体異常の経時的変化の解析
菅弘大'²、浅利郁江'、梅津真人'、今井佑磨'、藤嶋洋平''、Valerie Swee Ting Goh '、佐々木直美'、有吉健太郎''、三浦富智²³、山田裕°、吉田光明* ¹ '弘前大学被ばく医療総合研究所、'弘前大学医学部保健学科、'弘前大学大学院保健学研究科、'東北大学医学部、 5福島県立医科大学、6量子科学技術研究開発機構*責任著者: myoshida@hirosaki-u.ac.jp原爆被爆者を対象とした疫学解析では被爆して数年後に造血系腫瘍の発生頻度が上昇することが示されている。そこで、本研究では低線量率放射線の影響を解析する予備実験として、マウスを対象とし、放射線被ばく後に起こる染色体異常について経時的変化を解析した。さらに、放射線感受性マウス（C3H）と放射線耐性マウス(B6)を用いて、 2系統間の差についても解析を行った。8週齢C57BL/6NJclマウス及びC3H/HeJJclマウスに4Gy(1Gy/min)のX線を照射し、1、2、3、6ヶ月後に造血系組織（骨髄、脾膜、血液）から染色体標本を作製し、ヘキスト-キナクリン二重染色で染色体異常を解析した。その結果、C3HとB6ともに1、2、3、6ヶ月後に染色体異常を解析したが、両系統とも照射後6ヶ月経過した段階でさえ異常頻度は高く、また、C3Hでは比較的ランダムに染色体異常が生じる傾向がみられたが、B6では特定の染色体（1、8、10、11、12、13、15番染色体）が高い異常頻度を生じる傾向にあった。また、個体によっては骨髄、末梢血、脾膜に共通したクローン性の異常も確認された。これらの結果から、照射時には様々な染色体異常が誘発されるが、時間の経過とともに増殖能の優位な細胞がクローナルに拡大し、悪性化していく可能性が示唆される。今後は、照射後６ヶ月以上の時間の経過後の染色体異常の動向が注目される。これらの結果をもとに、今後は低線量率放射線の影響を解析したい。キーワード：放射線照射、染色体異常、経時的変化、造血系組織
P-51
Establishment of a dose response curve for dicentric chromosome
analysis in wild boar
Hiroko Ishiniwa* ¹ , Donovan Anderson ² , Yohei Fujishima ³ , Kei Okuda ⁴ , Mitsuaki Yoshida ⁵ , Toshiya Inaba ⁴ , Akiko Nagamachi 6 , Nanba Kenji ¹.² , Tomisato Miura 5,7 1 Institute of Environmental Radioactivity, Fukushima University ² Graduate School of Symbiotic Systems Science and Technology, Fukushima University ³  School of Medicine, Tohoku University 4 Faculty of Human Environmental Studies, Hiroshima Shudo University 5 Department of Radiation Biology, Institute of Radiation Emergency Medicine, Hirosaki University 6 Research Institute for Radiation Biology and Medicine, Hiroshima University 7 Graduate School of Health Sciences, Hirosaki University *Corresponding author: ishiniwa@ier.fukushima-u.ac.jp Dicentric chromosomal aberration is a radiation induced DNA lesion that is used to estimate radiation dose as its frequency of occurrence increases in a dose-dependent manner. To accurately estimate radiation dose, it is essential to establish a dose response curve obtained from the relationship between radiation dose and the frequency of dicentric chromosome aberrations. In this study, we tried to establish a dose response curve to estimate radiation doses for wild boar living in the evacuation zone in Fukushima. The blood of wild boar collected in non-contaminated areas were irradiated at 0, 25, 50, 75, 100, 250, 500, 750, 1000, 1500, 2000 mGy using both a high and low dose Cs-source (85 mGy/h、0.2 Gy/min, respectively), then blood cells were cultured according to standard protocol of the International Atomic Energy Agency, and lymphocytes were collected. In this presentation, we will introduce the current results of dicentric chromosome frequency. Keywords : radiation, dicentric analysis, standard curve, wild boar
イノシシにおける二動原体染色体の検量線作成
石庭寛子* '、アンダーソンドノヴァン'、藤崎洋平'、奥田圭'、吉田光明'、稲葉俊哉'、長町安希子'、難波議二12 、三浦富智57 ¹福島大学環境放射能研究所²福島大学共生システム理工学類³東北大学大学院医学系研究科‘広島修道大学人間環境部5弘前大学大学院保健学研究科6広島大学原爆放射線医科学研究所 弘前大学被ばく医療総合研究所*責任著者: ishiniwa@ier.fukushima-u.ac.jp二動原体染色体は放射線被曝によって起こるDNA損傷の一種であり、被ばく線量依存的に発生頻度が増加することから、被ばく線量推定に利用されている。被ばく線量を正確に推定するためには、放射線量と二動原体染色体の発生類度との関係から得られる検量線の確立が必須である。本研究では、福島県の帰還困難区域に生息するイノシシの被ぼく線量を推定するため、検量線の作成を行った。非汚染地域で捕獲されたイノシシの血液に0, 25, 50, 75, 100, 250, 500, 750, 1000, 1500, 2000 mGyの異なる線量率(約85 mGy/h、0.2 Gy/min)のセシウム線源放射線を照射し、国際原子力機関の標準プロトコルに従い培養し、リンバ球を回収した。本発表では、二動原体染色体の発生頻度の計測結果について紹介する予定である。キーワード：放射線、二動原体染色体、検量線、イノシシ
P-52
Comparative studies between field and irradiation experiments for elucidation of environmental effects by the Fukushima Daiichi Nuclear Power Plant accident Yoshito Watanabe* ¹ , Vasyl Yoschenko ² , Shoichi Fuma ¹ , Kouichi Maruyama ¹ , Yutaka Yamada ¹ 1  Center for Advanced Radiation Emergency Medicine, National Institutes for Quantum and Radiological Science and Technology (QST), ² Institute of Environmental Radioactivity (IER), Fukushima University *Corresponding author: watanabe.yoshito@qst.go.jp For the purpose to elucidate radiation effects on the environment after the Fukushima-daiichi nuclear power plant (F1NPP) accident, IER has a great advantage in field study of contaminated areas. On the other hand, QST has a potential in biological experiments using irradiation facilities. Accordingly, we undertook collaborative studies between the field and irradiation experiments on wild organisms including forest trees. In forest trees, a field study by IER has reported increased frequency of morphological changes in Japanese red pine in highly contaminated area near the F1NPP. To verify the relationship between radiation exposure and morphological changes in pine trees, irradiation experiments were conducted under a well-controlled conditions at the irradiation facility in QST. The irradiation facility is equipped with 137Cs radiation source, which enables long-term irradiation of the organisms at 100 μGy/day – 50 Gy/day. Potted young seedlings of Japanese red pine are set up at plots within the irradiation facility to cover the range of the estimated radiation dose rates of the wild pine trees between 0 (control) and 2 mGy/day. The experiment was carried out under environmentally controlled conditions simulating seasonal temperature changes. After 6 months of continuous irradiation, most trees were transplanted to a field for a long-term growth observation in IER, whereas the other trees are still under irradiation for analyses of effects by years of continuous irradiation. Keywords : radiation effects, Japanese red pine, irradiation experiments
福島第一原子力発電所事故による環境影響を解明するための野外と照
射実験の比較研究
渡辺嘉人* ¹、Vasyl Yoschenko ²、府馬正一¹、丸山耕一¹、山田裕¹ '量子科学技術研究開発機構高度被ばく医療センター ²福島大学環境放射能研究所*責任著者: watanabe.yoshito@qst.go.jp福島第一原発事故による環境影響を解明するために、福島大学環境放射能研究所では野生生物の野外調査を行っている。一方量研では、放射線照射装置を用いた生物の屋内照射実験が可能である。そこで本拠点間共同研究では、高線量地域の野外で報告されている野生生物の変化と放射線被ばくとの関係について、屋内照射実験との比較により検証することを目的としている。ここでは、福島大学環境放射能研究所が報告している「高線量地域におけるアカマツの形態変化」を検証するため、量研のガンマ線照射施設でアカマツの被ばく状況を再現する方法を検討した。高汚染地域におけるアカマツの被ばく線量率の推定に基づき4段階の照射区を設け、野外の気温・日照を模擬した人工気象下でアカマツのポット苗を栽培した。夏～春まで照射した苗についてフィールドに移植して生育の観察を続ける一方で、一部の植物体については１年以上にわたってガンマ線照射を継続している。キーワード：放射線影響、アカマツ、照射試験
P-53
Radiocesium bioavailability and radiocesium-bearing microparticles in
aquatic insects of Ota River
Yumiko Ishii* ¹ , Jaeick Jo ¹ , Seiji Hayashi ¹ , Hikaru Miura ² , Daisuke Tsumune ² , Toshihiro Wada ³ , Tsutomu Kanasashi 3 , Kenji Nanba 3,4 , Wataru Teramoto 5 , Tadahiro Sohtome 5 , Rie Saito 6 ¹ Fukushima Branch, National Institute for Environmental Studies, ² Central Research Institute of Electric Power Industry, 3 Institute of Environmental Radioactivity at Fukushima University, 4 Faculty of Symbiotic System Science, Fukushima University, 5 Fukushima Prefectural Inland Water Fisheries Experimental Station, 6 Fukushima Prefectural Centre for Environmental Creation *Corresponding author: ishii.yumiko@nies.go.jp Aquatic insects are thought to be an important food resource for freshwater fish to take up radiocesium in mountain streams. Relatively high 137Cs concentrations in Stenopsyche marmorata have been reported, which is due to the contents of the digestive tract of this species feeding on algae and litter with high 137Cs concentration. However, bioavailability of 137Cs in aquatic insects is unknown: how much of 137Cs is absorbed into aquatic insect tissues and fish body tissues ? In this study, we measured directly 137Cs concentrations in contents of gastrointestinal tract and muscles of aquatic insects by dissecting aquatic insects of different feeding habits including S. marmorata. The trophic transfer factor, which is calculated by dividing 137Cs concentration in muscle by 137Cs concentration in contents of gastrointestinal tract, was compared as an indicator of bioavailability. As a result, the trophic transfer factor varied depending on the feeding habits of aquatic insects. In addition, individual measurement of 137Cs concentrations of S. marmorata sometimes showed extremely high concentrations. The analysis of the aquatic insect samples using autoradiography with imaging plates and electron microscope identified the radiocesium-bearing microparicles in some samples. This result indicated that the presence of high radioactivity particles such as radiocesium-bearing microparicles is one of the causes of the high variation in the 137Cs concentration, especially when measuring a small amount of sample such as aquatic insects. Keywords : 137Cs, aquatic insects, river, trophic transfer factor, cesium ball
太田川の水生昆虫における放射性セシウムの生物利用性と
放射性セシウム粒
石井弓美子* ¹、趙在翼¹、林誠二¹、三浦輝¹、津旨大輔¹、和田敏裕¹、金指努¹、難波謙二¹¹、寺本航¹早乙女忠弘5、斎藤梨絵6 '国立環境研究所福島支部、'電力中央研究所環境科学研究所、'福島大学環境放射能研究所、 ‘福島大学共生システム理工学類、‘福島県内水面水産試験場、‘福島県環境創造センター *責任著者: ishii.yumiko@nies.go.jp水生昆虫は、渓流において淡水魚類が放射性セシウムを取り込む際の重要な餌資源であると考えられる。放射性セシウム濃度の高い藻類やリターを餌とするヒゲナガカワトピケラでは、消化管内容物の影響で高い137Cs濃度が検出されるが、それがヒゲナガカワトピケラの体組織、また餌として食べられた際に魚の体組織に、どの程度吸収されるかといった生物利用性については未知である。本研究では、ヒゲナガカワトピケラを含む藻類食・肉食の水生昆虫を解剖することによって、水生昆虫の消化管内容物と筋肉部の137Cs濃度を直接測定し、筋肉部の137Cs濃度を胃内容物の137Cs濃度で割った栄養段階間移行係数を、生物利用性の指標として比較した。その結果、栄養段階間移行係数は、水生昆虫の食性によって異なっていた。また、ヒゲナガカワトピケラの137Cs濃度を個体ごとに測定すると、極端に濃度の高い個体が観察された。これらの個体から湿式分離法により高級量粒子を単離し、放射能測定と電子顕微鏡での観察を行った結果、これまでに報告されている放射性セシウム粒子の特徴と一致した。水生昆虫などの微量試料の測定の際には、放射性セシウム粒子などの高線量粒子の存在が、放射性セシウム濃度を大きくばらつかせる原因の一つになっていると考えられる。キーワード： 137 Cs、水生昆虫、河川、栄養段階間移行係数、放射性セシウム粒子
P-54
Multi-sources images time-series for landscape dynamics analysis in
rural areas after Fukushima accident
Lissak Candide * ¹ , Onda Yuichi ² , Kato Hiroaki ³ , Preux Thibaut 4 , Dufour Simon ⁵ 1 LETG Caen, University Caen Normandie, France 23 CRiED Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Japan 45 LETG Rennes, University Rennes 2, France *Corresponding author: candide.lissak@unicaen.fr Since the accident of the Fukushima power plant in 2011, several evacuation orders have been issued. This kind of fast and massive evacuation proceed is exclusive and can provide unique experimental sites to observe methods of vegetation recovery in agricultural areas. Usually, recovery processes are induced by a gradually abandonment of agricultural practices. These processes are characterized by several steps of landscape transformation from opened areas (agricultural plots) to closed areas (wasteland until forest recovery). Our study focuses on the evolution of the agricultural plots (paddy rice, cropland…) in Namie town in Fukushima prefecture, where decontamination campaigns were limited until now (decontamination visible in 2015). In this context of observatory, multi-source and multi- resolution data can be useful to define landscape trajectories in territories avoided of population and under a limited anthropic influence. To study spatial and temporal characteristics of recovery processes satellite imagery is one of the primary sources of information. In this study, the procedure relies on SPOT and Pleiades times series analysis for crop- mapping. We tested the use of Enhanced Vegetation Index (EVI) and traditional Normalized Difference Vegetation Index (NDVI) to detect vegetation recovery patterns before and after Fukushima accident (from 2009 to 2019).  We only focus our research on agricultural plots to spatialized information about scrub invasion, and through wavelet analysis evolving in time. Keywords :
P-55
Contribution of K transporters to Cs uptake and accumulation in rice
Nathalie Leonhardt* ¹ , Satomi Kanno ² , Shigeto Fujimura ³ , Takuro Shinano 4 , Jun Furukawa ² 1 French Alternative Energies and Atomic Energy Commission ² Institute for Advanced Research, Nagoya University ³ Tohoku Agricultural Research Center, National Agriculture and Food Research Organization 4 Research Faculty of Agriculture, Hokkaido University 5 Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: nathalie.leonhardt@cea.fr The aim of the project is to develop safe-food or in-situ remediation approaches using plants for rehabilitation of soil. In the plants, 137 Cs radiological contaminant enters using K+ transport systems by chemical analogy. To decipher the molecular mechanisms of Cs uptake and accumulation, we have characterized several rice mutants that are affected in different K+ transport systems in CEA and evaluated those 137Cs accumulations in natural paddy field belong to NARO Agricultural Radiation Research Center in 2018. Among the several candidate lines, HKT2;1 KO lines have been shown to be affected in Cs uptake or accumulation compare to wild-type plants in the paddy field. In order to validate the results obtained in natural paddy field experiment in 2018, HKT2;1 KO lines were cultivated the same paddy field again and two different K conditions (with or without K fertilizer) were also tested. Around 10 plants of two independent HKT2;1 KO lines were cultivated until harvesting grains (4.5 months, from June to October). Then, the 137Cs contents were measured in grains. Our results showed the differences in K+ concentration in presence or absence of fertilizers were not appeared in all tested lines, however, we observed differences in 137Cs contents in grains between HKT2;1 KO lines and control lines again. The mutant line disrupted in the HKT2;1 gene that is expressed in whole plants and highly expressed in the root, shown an increased 137Cs content in grains. To confirm these results, we would like to perform laboratory condition experiments and a new paddy field experiment in 2020. Keywords : 137Cs, K+ transport system, HKT2;1
P-56
Characteristics of chemical compositions of xylem sap in a pine forest
under environmental changes
Sun Xinchao* ¹ , Onda Yuichi ² ¹ Institute of Surface-Earth System Science, Tianjin University ² Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: xinchao.sun@tju.edu.cn Trunk xylem is the major conduit for transport of minerals to photosynthetically active leaves from root uptake and assimilation. Studying variations in chemical compositions of xylem sap is thus of basic interest as it reflects the internal minerals uptake and cycling of forest trees. Until now, however, our knowledge of xylem transport in forests under natural conditions and the regulation of this transport are not well understood. We thus depicted the level and behavior of chemical components and stable isotopes in the xylem sap of trunks and branches of different aged trees from a pine forest in northern China. There were no significant differences between the centrifugation and water displacement methods with respect to nitrogen (N) compounds and inorganic ions in the xylem sap. Potassium concentrations obtained by the methods were similar and consistent with the values obtained from earlier publications on woody species. This suggests that the centrifugation method would be a reliable and robust tool for collection of the trunk xylem sap. Additionally, during foliage senescence, dissolved organic N was the dominant component of total N followed by nitrate (NO3') and ammonium (NH4*). Potassium and chloride were the predominant cation and anion, respectively, of the xylem sap. More inorganic N components (mainly NO3') were found in young trees than in old trees. The N components in the trunk xylem sap showed obvious diurnal changes. The N isotope ( 15N ) decreases and then increases during transport from the root to the canopy, and was positively correlated with the phloem sap 15N, indicating that the xylem sap in the trunk had a close exchange with the phloem sap during the xylem sap transport. Our study contributes to improve the diagnostic assessments of tree physiological processes and growth in forest trees under environmental changes. Keywords : xylem sap, stable isotope, sap flow, plant nutrient transport, plant nutrient utilization
P-57
Determination of local ecological factors on soil-to-plant transfers in
Fukushima forest ecosystems
Vasyl Yoschenko* ¹ , Alexander Brandl ² , Jian Zhang ² ¹ Institute of Environmental Radioactivity, Fukushima University ² Environmental and Radiological Health Sciences, Colorado State University ³ Environmental and Radiological Health Sciences, Colorado State University *Corresponding author: r705@ipc.fukushima-u.ac.jp Radiocesium contamination from the March 2011 accident at the Fukushima Da-ichi Nuclear Power Station (FDNPS) was initially deposited on the forest canopies with deposition into the soil occurring over the next few years through litterfall and precipitation. Measurements taken from the Yamakiya site in 2014 show that the contribution of understory plants to the total inventory of radiocesium in aboveground biomass was very low compared to the dominant Japanese cedar trees. However, measurements were not taken in other affected sites within Fukushima prefecture as well as potential change in concentrations of radiocesium in understory biomass since 2014. Data for evaluating the transfer factors was obtained through sampling of soil and understory plants at the Yamakiya, Tsushima, Tomioka, Okuma, and Yokomuki sites inside Fukushima Prefecture. Both 134Cs and 137Cs measurements were collected, however 134Cs concentrations were negligible compared to 137Cs so only 137Cs data was considered. 137Cs content was determined using gamma spectroscopy of the soil and plant samples and to find the concentration of bioavailable 137Cs within the root profile of the understory plants as well as 137Cs concentration within the understory plant itself. The soil and plant 137Cs concentration were used to determine the soil-to-plant uptake factors for the sampled understory species as well as the contribution of the understory plants to the total 137Cs inventory in aboveground biomass. The effect of soil exchangeable K+ and Cs+ concentration, and pH on 137Cs uptake by understory plants will be determined through the soil-to-plant uptake factors at the various sample sites. The further understanding of 137Cs dynamics in forest ecosystems will assist in creation of a long-term forest radiation contamination management strategy. This will contribute to potential future studies of internal 137Cs uptake by herbivores that grazes on the understory plants. Keywords : Fukushima, Yamakiya, Tsushima, Tomioka, soil, understory plants, 134Cs, 137Cs, potassium, cesium, forest, cesium dynamics, plant uptake, total cesium inventory
P-58
Effects of radionuclide exposure on microbiome of wild boar
Jim Beasley* ¹ 2 , Kenji Nanba ³ 4 , Sarah Chinn ¹ , Kakeru Ambai 4 , Diana Lafferty 5 ¹ University of Georgia Savannah River Ecology Laboratory, ² University of Georgia Warnell School of Forestry and Natural Resources ³ IER, Fukushima University, 4 Faculty of Symbiotic System Science and Technology, Fukushima University 5 Department of Biology, Northern Michigan University *Corresponding author: beasley@srel.uga.edu Microbiome analysis of the digestive tract of a mammal is variable according to the composition of their diet.  The health condition of the digestive tract is vulnerable to specific chemical substances (i.e. ammonium, phenols etc.) that microorganisms produce, and different microbial communities exists in different parts of digestive tract. Health of mammals is also related to the composition of their microbiome.  For example, the mirobiome of the digestive tract is known to have a role in the development of immune system and a normal microbiome help the host to protect from pathogenic microorganisms such as Salmonella. Microbiome of wild boar in the area of Fukushima where radiation level is elevated after the NPP accident can be influenced by the radiation directly or by indirect effects such as human evacuation.  As the microbiome of the digestive tract can be an indicator of health condition of wild boar, comparison of the microbiome of digestive tracts of various individuals of wild boar captured in Fukushima was attempted. Microbiome analysis is attempted based on NGS of the extracted DNA from the content of 7 different parts of digestive tract of 42 individuals of wild boar captured in Jan-Mar 2019. In 2019 DNA extraction by a modified protocol using Quagen DNEasy Power Soil kit to increase purity of DNA was started, and the analyses are ongoing. Keywords : Fukushima, wild boar, digestive tract, microbiome, DNA
野生イノシシのマイクロバイオームに対する放射線影響
ジムビーズリー * ¹² ,難波謙二³¹ ,サラチン¹ ,安倍翔¹ ,ダイアナラファティ5 ¹ジョージア大学サバンナリバー生態学研究所、²ジョージア大学森林・天然資源学ウォーネルスクール, ’福島大学環境放射能研究所、‘福島大学共生システム理工学類・大学院共生システム理工学研究科5ノーザンミシガン大学生物学部*責任著者: beasley@srel.uga.edu哺乳類の腸内細菌叢は摂取する餌によって大きな影響を受ける。また,消化管の健康状態が消化管内の微生物によって生産される，例えばアンモニアやフェノール類等特定の化学物質によって影響を受けることが知られている。また，消化管の部位により存在する細菌が異なる。哺乳類において腸内細菌叢（マイクロバイオーム）が健康状態と関係している。例えば，健康な微生物叢は、免疫の発達においてだけではなくサルモネラ菌などの特定の病原体に対する保護にも役立っているとされている。放射線の直接的な影響や，住民の避難などによる間接的な影響により，イノシシの腸内細菌嚢が変化している可能性がある。イノシシの健康状態と関係していることから，健康状態の指標と考えることができる腸内細菌嚢の分析を行い，個体間で比較する。福島県内で捕獲されたイノシシの消化管内容物中のDNAの塩基配列から微生物組成を分析する。2019年1月から3月の間に県内で捕獲された42個体のイノシシについて、７カ所の異なる消化管の部位から採取した。この研究では第一段階としてマイクロバイオーム分析用のDNA抽出を行った。抽出にはQuagen DNEasy Power Soilキットを用いるが，DNAの純度を向上させるために改変したプロトコルを用いた。キーワード：福島、イノシシ、消化管、マイクロバイオーム、DNA
P-59
Determination of radiation dose to Large Japanese Field Mice in the
vicinity of Fukushima Daiichi Nuclear Power Plant
Mariah Davis* ¹ , Thomas Johnson ¹ , Tsugiko Takase ² , Yuki Odagiri ² , Yusuke Mitsuyasu ² , Hisashi Shinoda ³ , Toshitaka Oka 4 , Hiroko Ishiniwa ² 1 Colorado State University ²  Fukushima University ³  Tohoku University 4 Japanese Atomic Energy Agency *Corresponding author: mariahld@rams.colostate.edu Electron spin resonance (ESR) analysis of tooth enamel is recognized as a reliable method for lifetime dose reconstruction, particularly in human tooth enamel. While the use of ESR to reconstruct dose is well understood for human tooth enamel, the reliability and usefulness of dose reconstruction using ESR in mouse tooth enamel has not been as thoroughly studied. This research aims to confirm the minimum detectible dose in the teeth of the Large Japanese Field Mouse for a reliable and useable ESR spectroscopic response. Initial sample preparation methodology followed a basic ESR sample preparation procedure, including manual removal of non-enamel tooth components, followed by a 15% by weight NaOH solution in a sonic bath to dissolve dentin. Preliminary sample preparation methodology revealed a baseline shift in spectrum output, meaning that teeth could not be reliably used to reconstruct dose. A possible source of this shift was attributed to remaining dentin in the samples, or iron components in tooth structure, though iron was not seen in the samples following analysis with energy dispersive x-ray (EDS) analysis. New sample preparation methodology included an extra step using a solution of Titriplex III (EDTA) to remove spurious signal causing the baseline shift, but did not reliably resolve the problem. Because the new procedure did not reliably remove the signal baseline shift, further consideration of causes of the baseline shift will be made, and removal of the shift via mathematical methodology, or further sample preparation methodology, will be attempted. If the baseline shift is successfully resolved, tooth enamel samples will be dosed across a range (below 0.8 Gy, to 2 Gy) to test currently known dose limits in mouse teeth, and to analyze usability of mouse teeth to reconstruct lifetime dose. Keywords : electron spin resonance, ESR, electron paramagnetic resonance, EPR, Large Japanese Field Mouse, mouse, mice, Apodemus speciosus, lifetime dose reconstruction, dose reconstruction
P-60
Estimation of biomass and stocks biologically mobility radionuclides

D. Holiaka* ¹ , H. Kato ² , V. Yoschenko ³ , Y. Onda ² , Y. Igarashi ³ , K. Nanba ³ , P. Dyachuk ¹ , R. Zahorodnuk ¹ 1 The National University of Life and Environmental Sciences of Ukraine, Ukraine ² Center for Research in Isotopes and Environmental Dynamics at University of Tsukuba, Japan, ³ Institute of Environmental Radioactivity at Fukushima University, Japan *Corresponding author: holiaka_d_m@ukr.net The study was carried out in the forest areas of the Chernobyl exclusion zone at the distances 4-12 km from the Chernobyl NPP industrial site. Forests cover about 60% of this area and Scots pine (Pinus sylvestris L.) is the dominant tree species spreading onto 60% of the forest area. During 2018-2019 we performed the UAV aerial photo surveys in 13 photo-stereogrammetric polygons where we established 31 experimental sites of pine stands. Biometric indicators of pine trees at forest sites have been determined to assess the aboveground biomass of stands with the help of regional bio-productivity regression equations for forest woody species. We had obtained descriptive statistics for CHM (Canopy Height Model) raster within experimental sites. A strong correlation between aboveground biomass for components stocks of pine stands and the arithmetic mean of CHM raster was detected (Spearman's rank correlation coefficient is 0.82), that allowed us to construct a simple linear regression on these indicators (with R2=0.79). Furthermore, tree crowns in the forest sites were identified. The modified R-script of package 'ForestTools' was used to conduct further analysis. Parameters for tree crowns were determined, namely local highest points (top of a tree crowns) and canopy area or radius of the crown. The implementation of the algorithm of this R package requires the introduction of additional indicators of tree crowns, which have a significant impact on the output results of their segmentation into different individual trees: this is the functional dependency of search radius on the height of trees and the minimum height for treetops and their crowns. Preliminary results of crown segmentation and identification of treetops allowed us to estimate the aboveground biomass of pine stands with slightly higher predictive ability (R2=0.82) using combination allometric dependencies. These approaches developed in the Chernobyl forest sites were applied to Japan in order to estimate the stand characteristics of the contaminated forest stands in Namie town of Fukushima prefecture. Keywords : forest inventory parameters; regression; aerial survey; UAV; GIS; raster images; tree; canopy height model (CHM)
P-61
Elucidation of transfer pathways of radiocesium in terrestrial
invertebrates
Sota Tanaka* ¹ , Hotaru Kakinuma ² , Tarô Adati ² , Mariko Atarashi-Andoh ¹ , Jun Koarashi ¹ 1 Japan Atomic Energy Agency, Research Group for Environmental Science ² Tokyo University of Agriculture *Corresponding author: tanaka.sota@jaea.go.jp Terrestrial invertebrates can be an indicator species of long-term behavior of radiocesium ( 137 Cs) through the food chain because of their large biomass and importance as food resources for other organisms. In particular, the Joro spider, Nephila clavata, as a generalist predator, is considered an indicator species of 137Cs contamination in insect communities because they prey on a variety of food resources from both grazing and detrital food chain. In the present study, the aggregated transfer factor (Tag) of 137Cs for the spiders inhabited in a mountainous forest and the adjacent riverside area was estimated based on the 137Cs activity concentrations in the spiders and the initial 137Cs deposition densities map. The geometric means of Tag values were 0.0013 m2 kg-1 (Min-Max: 0.0004–0.008 m2 kg-1, n=10) and 0.0008 m2 kg -1 (Min-Max: 0.0002–0.002 m2 kg -1, n=7) for the mountainous forest and the riverside, respectively. To investigate factors affecting the Tag values for spiders in these area, stable carbon and nitrogen isotope ratios of the spiders were measured. Results showed that average values of the isotope ratios in spiders were higher ( δ  13C: − 24.7 ± 1.1‰ ,  ô  15N: 5.4 ± 0.9‰ ) in the mountainous forest than in the riverside area ( ô  13C: − 26.2 ± 0.6‰ , ô  15N: 3.8 ± 0.8% ), suggesting that the transfer of 137Cs to spiders in the mountainous forest would be more dependent on detritus pathway (i.e., predation of organisms feeding on degraded, isotopically enriched organic materials) compared with the riverside area. Keywords : spider, radiocesium, aggregated transfer factor (Tag), stable carbon and nitrogen isotope ratios ( δ  13C, δ 15N), transfer pathways
陸生無脊椎動物における放射性セシウムの移行経路の解明
田中草太* ¹、柿沼穂垂²、足達太郎²、安藤麻里子¹、小嵐淳¹
日本原子力研究開発機構環境動態研究グループ²東京農業大学*責任著者: tanaka.sota@jaea.go.jp陸生無脊椎動物は、バイオマス量が多く、他の生物の餌貧源として重要であるため、食物連鎖を介した放射性セシウムの長期移行挙動を解明する上で重要な指標になりうる。特に、ジョロウグモは、広食性の捕食者として、生食連鎮と腐食連鎖の双方から様々な餌資源を捕食するため、昆虫類の放射性セシウム汚染の指標となることが示唆されている。本研究では、山林と川沿いに生息するジョロウグモの137Csの面移行係数（Tag）を初期沈着量マップを用いて算出した。その結果、Tag価の幾何平均は、山林で0.0013 m2 kg -1 (Min-Max: 0.0004-0.008 m2 kg -1, n=10)、川沿いで0.0008 m2 kg-1 (Min–Max: 0.0002–0.002 m2 kg-1, n=7)であった。生息地による移行係数の違いの要因を明らかにするため、ジョロウグモの炭素・窒素安定同位体比（ δ 13C、 δ 15N）を測定した結果、いずれの安定同位体比においても、山林（δ  13C: -24.7 ±  1.1‰ ,  δ  15N: 5.4 ±  0.9‰）で、川沿い（δ  13C: -26.2 ±  0.6‰ ,  δ  15N: 3.8 ±  0.8‰）よりも高い値を示した。これにより、山林に生息するジョロウグモにおける高い137Cs移行係数は、腐食連鎖由来の餌資源への依存が大きいためである可能性が示唆された。キーワード：ジョロウグモ、放射性セシウム、面移行係数（Tag）、安定同位体比（♂ 13C、δ 15N)、移行経路
P-62
Search for wild species of the genus Vigna without accumulating
cesium at the shoot apex
Yusaku Noda* ¹ , Jun Furukawa ² ¹ The National Agriculture and Food Research Organization, Genetic Resource Center ² University of Tsukuba, Center for Research in Isotopes and Environmental Dynamics *Corresponding author: Yusaku.Noda@ulb.ac.be The purpose of this research was to evaluate the cesium (Cs) accumulation ability in the salt-tolerant wild species of the genus Vigna and to produce the low Cs accumulation plant. We revealed that Cs accumulation of 4 salt-tolerant species ( V. nakashimae, V. riukiuensis, V. luteola and V. marina ) would have similarities and differences with the accumulation of the homologous element sodium (Na). However, all species showed high Cs accumulation at the shoot apex, and we could not evaluate it as low Cs accumulation plants. Here, we evaluated Cs accumulation in salt-tolerant species V. vexilatta ( V. vexilatta var. ovata and V. vexilatta var. macrosperma ) and V. trilobata (JP205895 and JP210605). As the results, all plants showed high Cs accumulation at the shoot apex. We found that most of 8 strain in 6 species has tolerant mechanism that suppress Na transport to the shoot apex, however, Cs transport to the shoot apex would not be mediated by these Na tolerant mechanism. Keywords : the genus Vigna , cesium, sodium, imaging plate
整頂部にCsを蓄積しないVigna属耐塩性野生種の探索
野田祐作* ¹、古川純²
¹農研機構遺伝資源センター ²筑波大学アイソトープ環境動態研究センター *責任著者: Yusaku.Noda@ulb.ac.be本研究目的はVigna耐塩性野生種のセシウム（Cs）酱積能の評価から、Cs吸収抑制植物を作出することである。これまでに耐塩性野生種4種（V. nakashimae、V. riukiuensis、V. luteolaおよびV. marina）のCs蓄積は、同族元茶であるナトリウム（Na）の蓄積と共通点や違いがあることを明らかにした。だが、いずれの野生種も茎頂部にCsが高蓄積しており、Cs低吸収植物と評価できなかった。そこで、新たに耐塩性野生種V. vexilatta (V. vexilatta var. ovataおよびV. vexilatta var. macrosperma)およびV. trilobata(JP205895およびJP210605)のCs蓄積を評価した。その結果、いずれも茎頂部にCsが高蓄積していた。これまでに解析した6種8系統のほとんどはNaを茎頂へ輸送しない機構を持っていたが、Csにはその制御機構は作用せず茎頂部に蓄積することが分かった。キーワード：Vigna属、セシウム、ナトリウム、イメージングブレート
P-63
Radiocesium concentrations in wild boar captured within 20 km of the
Fukushima Daiichi Nuclear Power Plant
Makiko Orita* ¹ , Noboru Takamura ¹ , Cui Limeng ¹ , Yasuyuki Yaira ¹ , Yumiko Yamada ¹ , Hirofumi Tsukada ² ¹ Atomic Bomb Disease Institute, Nagasaki University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: orita@nagasaki-u.ac.jp Due to the accident at Fukushima Daiichi Nuclear Power Plant (FDNPP) in 2011 large amounts of artificial radioactive substances were released into the environment. Tomioka town is located within 20 km of the FDNPP. After the accident, almost all residents evacuated. In April 2017, the town office decided to return to their hometown. In 2019, we measured the concentration of radiocesium in 202 muscle samples of wild boars captured in Tomioka town. 199 (98.5%) muscle samples still exceeded 100 Bq/kg. Radiocesium concentrations ranged from 87.1 to 8119.5 Bq/ kg with the median concentration was 433.1 Bq/kg. The median committed effective dose of taking a sample once has been estimated to be 0.23 μ Sv for females and 0.32 μ Sv for males. Our results showed the relatively high levels of radiocesium in wild boars captured in Tomioka. Long-term monitoring is needed to identify the time trend or seasonal change of radiocesium concentration in wild boars. Keywords :
富岡町におけるイノシシ中の放射性物質濃度評価
折田真紀子* '、高村昇'、崔力萌'、平良文亨'、山田裕美子'、塚田祥文* ¹長崎大学原爆後障害医療研究所²福島大学環境放射能研究所*責任著者: orita@nagasaki-u.ac.jp福島県双葉郡宮岡町は、東京電力福島第一原子力発電所事故によって全域避難を余儀なくされたが、2017年4月に帰還を果たした。今回は、2019年4月11日から12月27日までに町内で捕獲された202匹中のイノシシ肉中の放射性セシウム濃度を、ゲルマニウム半導体検出器を用いて測定した。202検体中199検体から国の基準値を超える放射性セシウムが検出された。放射性セシウム濃度の中央値は１キログラム当たり433.1ベクレル、最小値は87.1ベクレル、最大値は8119.5ベクレルだった。これらのイノシシを１回摂取した場合の預託実効線量の中央値は、雄で0.32μSv、雌で0.23μSvであった。多くのイノシシから現在の基準値を超える放射性セシウムが検出され、今後も注意深いフォローアップが必要であると考えられた。キーワード：
P-64
Elucidation of radioactive contamination level and establishment of extermination methods of invasive channel catfish toward the restoration of Fukushima’s inland water fisheries Junichi Takagi* ¹ , Toshihiro Wada ² , Hiromichi Mitamura ³ ¹ Guraduate School of Informatics, Kyoto University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: takagi.junichi.34w@kyoto-u.jp It is an urgent task to clarify the ecological characteristics of channel catfish Ictalurus punctatus in Abukuma River for the establishment of the suitable extermination methods for this invasive species, which are thought to increase drastically through reproduction around the hydroelectric dams. The aim of this study is to identify the spawning area in Shinobu Dam using acoustic telemetry techniques, and also to elucidate the radioactive contamination levels of this species. A total of 52 individuals (24 and 27 individuals in 2016 and 2017, respectively) surgically implanted with acoustic transmitters were released in Shinobu Dam. Eight receivers were deployed in the monitored 1.5 km area above the dam dike, and the additional receiver array was fixed around the potential spawning area. Results revealed that some individuals stayed around narrow areas (one to two sites) 500 m above the dike in June (spawning season), strongly suggesting the identified spawning sites. Mean 137Cs concentration of channel catfish (34.9 Bq/kg) was higher than those observed in smallmouth bass, common carp and crucian carp collected in 2016, suggesting that this species can be an indicator species of radioactive contamination in Abukuma River. Keywords : biotelemetry, spawning area, Abukuma River, Shinobu Dam, channel catfish.
福島県の内水面漁業復興に向けた外来種チャネルキャット
フィッシュの放射能汚染状況の解明と駆除手法の確立
高木淳一* ¹、和田敏裕²、三田村啓理¹ '京都大学院情報学研究科²福島大学環境放射能研究所*責任著者：takagi.junichi.34w@kyoto-u.jp福島県阿武隈川では、近年ダム周辺水域を中心に、再生産により外来魚チャネルキャットフィッシュが急激に増大していると考えられており、適切な駆除手法確立のための本種の生態解明が急務である。本課題では、バイオテレメトリーを用いて、阿武隈川信夫ダムにおける本種の産卵場所を特定するとともに本種の放射性セシウム濃度を明らかにすることを目的とした。超音波発信機を腹腔内に装着した52個体（2016年24個体、2017年27個体）を信夫ダムに放流した。調査水域約1.5 kmに8台の受信機を設置し、追跡した。また、多数の受信機を用いた音響アレイを配置し、より詳細な追跡を行った。測位データから、産卵期の6月に暖堤500m上流部付近の河岸沿いの1–2箇所の狭い範囲に、数週間程度留まる個体が複数観察され、産卵場と考えられた。2016年に採捕された本種個体の平均137Cs濃度は34.9 Bq/kgであり、コクチバスやコイ、ギンプナよりも濃度が高く、放射能汚染の指標種になると考えられた。キーワード：バイオテレメトリー、産卵場、阿武隈川、信夫ダム、チャネルキャットフィッシュ
P-65
Elucidation of radiocaesium migration characteristics in freshwater fish
inhabiting upstream Ota River
Wataru Teramoto* ¹ , Toshihiro Wada ² , Yumiko Ishii ³ , Seiji Hayashi ³ , Kenji Nanba 2,4
¹ Fukushima Prefectural Inland Water Fisheries Experimental Station ² Institute of Environmental Radioactivity at Fukushima University ³  Faculty of Symbiotic System Science, Fukushima University 4  Fukushima Branch, National Institute for Environmental Studies *Corresponding author: teramoto_wataru_01@pref.fukushima.lg.jp Although nine years have passed since the Fukushima Dai-ichi Nuclear Power Plant accident, radiocaesium concentration of freshwater fish is still significantly higher than that of sea fish, and, consequently, fishes in some lakes and rivers are listed as restricted foodstuffs for shipment. In this study, to predict the change in the radiocaesium concentration of freshwater fish, factors affecting its dispersion were examined. Specimens of freshwater fish, aquatic and terrestrial insects, river-bottom sediment, and river water were collected seasonally during April 2018 to December 2019 from four sites at Ota river in Fukushima Prefecture. 137Cs concentration of specimens (only edible part in the fish) was measured using germanium semiconductor detectors. Air dose rate at a height of about one meter above ground in the surrounding environment was measured by radiation detector. The dose rate and 137Cs concentration of the sediment, insects, white spotted charr Salvelinus leucomaenis, and masu salmon Oncorhynchus masou were higher in the upper site. 137Cs concentration of the water did not have such a tendency, while there were differences among sites. 137Cs concentration of the charr and salmon had a significantly positive correlation with total body length of them, and the obtained approximate straight line in the upper site showed a tendency to be larger inclination, whereas some values were deviated from the line. From the results of the degree of deviation and size-frequency distribution, it was suggested that some individuals could have migrated seasonally among sites, and the dispersion of 137Cs concentration of both fishes within the same site could have increased and decreased. Furthermore, the results will be discussed with stomach contents. Keywords : masu salmon, white spotted charr, 137Cs concentration, seasonal variation, differences among sites, river
太田川上流域における魚類への放射性セシウム移行特性の解明
寺本航* '、和田敏裕'、石井弓美子'、林誠二'、難波謙二''
'福島県内水面水産試験場、*福島大学環境放射能研究所、*国立環境研究所福島支部、 ‘福島大学共生システム理工学類*責任著者: teramoto_wataru_01@pref.fukushima.lg.jp東京電力福島第一原子力発電所事故後9年が経過した現在においても、淡水魚では海水魚に比べて放射性セシウム濃度が依然として高く、一部の魚種で水域により出荷制限や採捕自粛が続いている。漁業再開に向けた知見を得るためには、淡水魚への放射性物質の移行と蓄積過程を明らかにし、今後の淡水魚の放射性セシウム濃度の推移を予測することが重要である。本研究では、濃度推移予測の精度向上を図るため、生息環境、餌料生物、季節性など魚類の放射性セシウム濃度のばらつきに影響を与える要因について検討した。2018年4月から2019年12月にかけて計7回、太田川の４地点（各地点間2-3 km）にて電気ショッカー及び釣りにてイワナ・ヤマメを採捕し、同時に河川水・河床砂泥・昆虫類（水生・陸生）を採取した。採取した試料（魚類は可食部のみ）の137Cs濃度をGe半導体検出器により測定した。また、調査地点の空間線量率を放射線測定器を用いて測定した。空間線量及び河床砂泥・昆虫類・イワナ・ヤマメの137Cs濃度は上流ほど高い値を示した。河川水の137Cs濃度は調査地点間で異なっていたが、上流や下流ほど高いなどの傾向はなかった。調査地点ごとにイワナ・ヤマメの137Cs濃度と全長の間に有意な正の相関（サイズ効果）が認められ、上流ほど近似直線の傾きが大きくなる傾向があった。一方、近似直線から大きく外れた値が散見され、その程度と全長組成から個体によっては調査地点間を季節的に移動するため、同一地点内の魚類の137Cs濃度のばらつきが変化する可能性が示唆された。本講演では、さらに魚類の胃内容物に関するデータを含めて考察を行う。キーワード：イワナ、ヤマメ、137Cs濃度、季節変動、地点間差、河川
P-66
DNA analyses to estimate life-time dose from radiation exposures
estimation of life-time doses to wild boar using dicentric
chromosome analysis
Donovan Anderson* ¹ , Tomisato Miura ² , Yohei Fujishima ³ , Kei Okuda ¹ , Kenji Nanba ¹ 5 , Thomas Hinton ⁵ , Hiroko Ishiniwa 5 ¹ Fuculty of Symbiotic Systems Science and Technology, Fukushima University ² Department of Health and the Exposure Laboratory, Hirosaki University ³ School of Medicine, Tohoku University 4  Faculty of Human Environmental Studies, Hiroshima Shudo University 5 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: s1782002@ipc.fukushima-u.ac.jp A dicentric chromosomal aberration occurs as a result of DNA lesion from radiation exposure and quantifying dicentrics is a primary standard of cytogenetic biodosimetry, as it has the necessary sensitivity for assessing significant acute radiation doses. Recent studies have shown utility of dicentrics for determination of chronic doses, however, it is uncertain if it is sufficient at low radiation exposures. The opportunity to utilize cytogenetic biodosimetry methods as a dosimeter for chronic radiation exposures will improve future studies on dose-effect relationships on free-ranging mammals which inhabit areas that vary in dose levels. Thus, the objective of this study is to determine if quantifying dicentrics is a suitable biodosimetry method to estimate chronic radiation exposures to Japanese wild boar by comparing with other methods which also estimate radiation exposure. The research was conducted using 154 wild boars collected from multiple areas within the Difficult to Return to zone in Fukushima, which varied in levels of radiation exposure. Blood was incubated, cultured, and lymphocytes were harvested according to International Atomic Energy Agency standard protocol then analyzed for possible dicentrics. Concurrently, radiation dose of boars was estimated using a method based on internal measurements of radionuclide concentrations in muscle tissue and external measurements from ambient doses at capture sites multiplied by the corresponding estimated age of each boar. The current progress showed no relationship between the number of dicentric aberrations and estimated radiation dose. This result possibly indicates that radiation exposure observed in Fukushima may be too low to detect dicentrics in Japanese wild boar. Future analysis will be done on wild boar sampled in areas with higher radiation exposure and also done by other possible methods to estimate radiation dose to confirm our results. Keywords : dicentric, biodosimetry, low-dose chronic exposure
P-67
Development an approach to therapy for radition injury using Muse cell
Yohei Fujishima* ¹ , Takuma Hashimoto ¹ , Yusuke Urushihara ¹ , Li Gen ² , Mari Dezawa ² , Yoshio Hosoi ¹
¹ Department of Radiation Biology, Tohoku University School of Medicine ² Department of Stem Cell Biology and Histology, Tohoku University School of Medicine *Corresponding author: yohei.fujishima@med.tohoku.ac.jp In the event of a radiation accident or radiation therapy, it is important to cure the radiation injury in normal tissue. Currently, however, there is only steroid therapy and symptomatic therapy as possible strategy. Multilineage- differentiating stress-enduring (Muse) cells, identified as cells positive for the pluripotent marker stage-specific embryonic antigen-3 (SSEA-3), were discovered as stress-tolerant pluripotent stem cells. They also have an ability to differentiate into cells representative of all three germ layers (ectoderm, mesoderm, and endoderm) from a single cell and tolerate stresses. Clinical trials have been started in 2018, targeting acute myocardial infarct, stroke, and epidermolysis bullosa patients, and this suggest that Muse cell has a potential for tissue repairing. In this study, our goal is to examine the effectiveness of the Muse cell for radiation injury. And this study is also aimed to evaluate the radiation injury of each organ by using the distribution of Muse cell toward damaged tissue, and to estimate the radiation damage in the low dose range by obtaining the dose effect curve. We will discuss current results in this presentation. Keywords : Muse cell, radiation injury.
Muse細胞を用いた放射線障害に対する治療法の開発
藤嶋洋平* ¹、橋本拓磨¹、漆原佑介¹、李根²、出澤真理²、細井義夫¹
¹東北大学大学院医学系研究科放射線生物学分野
²東北大学大学院医学系研究科細胞組織学分野*責任著者: yohei.fujishima@med.tohoku.ac.jp緊急被ばく医療の被ばく者への対応や医療での放射線治療において、正常組織の放射線障害の治療は重要である。多能性幹細胞として知られるMuse細胞は、組織からSSEA-3陽性細胞として分離することが可能であり、外胚葉系、中胚葉系、内胚葉系の細胞に分化することができる。2018年１月より急性心筋梗塞、脳梗塞および表皮水疱症患者を対象とした探索的臨床試験が開始されており、障害を受けた組織の修復に効果的であることが臨床的にも強く示唆されている。本共同研究は、2 Gyの放射線を照射したSCIDマウスの放射線障害部位にMuse細胞が生着するか調べ、放射線障害の治療への有効性を評価することを目的としている。さらに、Muse細胞が障害を受けた組織に分布することを指標とし、臓器ごとの放射線障害を評価するとともに、線量効果由線を求めることにより低線量域での放射線障害を推定することを目的とする。本演題では現在得られている結果について紹介する。キーワード：Muse細胞、放射線障害
P-68
Investigation of biological behavior of radiocaesium in the body of
Japanese macaque
Yusuke Urushihara* ¹ , Masatoshi Suzuki ¹ , Yoshikazu Kuwahara ² , Yasushi Kino ¹ , Tsutomu Sekine ¹ , Hisashi Shinoda ¹ , Tatsuo Aono ³ , Manabu Fukumoto 4 , Yoshio Hosoi ¹ ¹ Tohoku University ² Tohoku Medical and Pharmaceutical University ³ National Institutes for Quantum and Radiological Science and Technology 4 Tokyo Medical University *Corresponding author: yusuke.urushihara.b3@tohoku.ac.jp We established a project for comprehensive exposure dose assessment for disaster-affected animals and collected tissue samples from more than 300 Japanese macaques inhabiting around FNPP. We previously reported that the radiocaesium activity concentration was highest in the skeletal muscle, high in submandibular gland and low in thyroid gland, brain, liver and thymus among 15 organs (Urushihara et al, KEK Proceedings 2017-6). In this study, we measured radiocaesium concentration in blood plasma of Japanese macaques and evaluated the relationship between radiocaesium levels in each organ. The radiocaesium activity concentration in the blood plasma was lowest among all organs we measured. Previous study reported that the mass of skeletal muscle is about 0.4 times the body mass in terrestrial mammals (Hoppeler et al, J Exp Biol.). These suggest that the transfer coefficient of blood plasma to skeletal muscle is significant higher than that of skeletal muscle to blood plasma. Keywords : Japanese macaque, radiocaesium, biological behavior
野生ニホンザルの体内放射性セシウム動態に関する研究
漆原佑介* '、鈴木正敏'、桑原義和'、木野康志'、関根勉'、篠田壽'、青野辰雄'、福本学'、細井義夫' 1東北大学²東北医科薬科大学³量子科学技術研究開発機構'東京医科大学*責任著者: yusuke.urushihara.b3@tohoku.ac.jp被災動物の包括的線量評価事業では福島原発事故により被災した野生ニホンザルの組織試料を採取・保管している。本研究では、セシウム体内動態の解析のために、ニホンザル組織試料の放射性セシウム濃度測定を行った。その結果、放射性セシウム濃度は骨格筋で最も高く、筋肉以外の組織では骨格筋に対して0.2 ～ 0.4倍程度の放射性セシウム濃度を示した。血漿は他の組織と比べて放射性セシウム濃度が最も低く、骨格筋に対して0.1倍以下であった。放射性セシウムは腸で取り込まれた後血漿から各臓器に運ばれることから、体内存在量の多い骨格筋では放射性セシウムの血漿から骨格筋への移行係数が骨格筋から血漿への移行係数に比べて顕著に大きいことが考えられる。今後血漿から各組織、また各組織から血漿へのセシウム移行係数の算出、及び同属元素の挙動との比較を行うことで、放射性セシウムの詳細な体内動態の解明に繋がることが期待される。キーワード：ニホンザル、放射性セシウム、体内動態
P-69
Population structure of wild boar in Fukushima Prefecture including
evacuation zone
Rie Saito* ¹ , Natsuko Kondo ² , Yui Nemoto ¹ , Reiko Kumada ¹ , Masanori Tamaoki ² ¹ Fukushima Prefectural Centre for Environmental Creation ²  National Institute for Environmental Studies *Corresponding author: saito_rie_01@pref.fukushima.lg.jp After the TEPCO Fukushima Daiichi Nuclear Power Plant accidents, the growing population of wild boars and is concerning around difficult-to-return zone. In addition, it is also concerning about wild boars dispersing from inside to outside in this area. In order to reduce the crop damage caused by wild boars, the capture of wild boars is reinforced under the law of Wildlife Protection and Hunting Management in Fukushima Prefecture. So, it is important to determining the population structure in order to properly control wild boars. We surveyed population structure of wild boar in Fukshima Prefecture using by MIG-seq (Multiplexed ISSR genotyping by sequencing) analysis. We used wild boar total 188 DNA samples captured by Fukushima Prefecture and Kumamoto Prefecture. In total of 688 SNPs were extracted. As the results of STRUCTURE analysis and Cluster analysis, it was revealed that wild boars in Fukushima Prefecture were divided into two clusters and these populations divided by east and west area along with Abukuma river. Keywords : wild boar, Sus scrofa , DNA, Fukushima Prefecture, MIG-seq analysis
避難指示区域及びその周辺地域を包括した福島県内におけるイノシシの
個体群構造の究明
斎藤梨絵* '、今藤夏子'、根本唯'、熊田礼子'、玉置雅紀'
¹福島県環境創造センター ²国立環境研究所*責任者者: saito_rie_01@pref.fukushima.lg.jp TEPCO福島第一原子力発電所事故後、帰還困難区域や居住制限区域内において、長期間の無居住化が生じたことで、生物の個体群に変化が生じていると考えられる。とりわけ、このような地域におけるイノシシの個体数の増加や、他地域への分散が懸念されている。イノシシは、農業被害をもたらす苦獣であることから、鳥獣保護管理法の下で捕獲が強化されている種である。適切なイノシシの管理には、帰還困難区域等の地域も含めた福島県内におけるイノシシの個体群構造を把握することが必要である。本研究では、福島県内に生息するイノシシのDNA解析を行うことで、県内におけるイノシシの個体群構造を明らかにすることを目的とした。福島県内広域及び熊本県より採取したイノシシ188頭のDNAを用いて、MIG-seq解析を行いゲノムワイドにSNPの選抜を行った。その結果、688座のSNPsが抽出された。これらの結果を用いて、Structure解析及びクラスター解析を行った結果、福島県のイノシシは、おおよそ阿武隈川の東側と西側の２つのクラスターに別れることが明らかになった。キーワード：イノシシ、Sus scrofa、DNA、福島県、MIG-seq解析
P-70
Pre- and post-accident 14C activities in tree rings near the
Fukushima Daiichi Nuclear Power Plant
Tetsuya Matsunaka* ¹ , Kimikazu Sasa ² , Masumi Matsumura ² , Shigekazu Hirao ³ , Yoshifumi Wakiyama ³ , Keisuke Sueki 2 ' Low Level Radioactivity Laboratory, Institute of Nature and Environmental Technology, Kanazawa University ² Accelerator Mass Spectrometry Group, University of Tsukuba 3 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: matsunaka@se.kanazawa-u.ac.jp Approximately 2.8 PBq of anthropogenic 14C was released from nuclear facilities worldwide from the 1950s, produced mainly by neutron activation reactions such as 14N (n, p) 14C, 17O (n, α ) 14C, and 13C (n, γ ) 14C in nuclear fuel, fuel cladding, water coolant, and graphite moderators. Areas affected by routine 14C discharges from the Fukushima Dai- ichi Nuclear Power Plant (FDNPP) and accidental releases in March 2011 were investigated by analysis of cores from Japanese cypress and cedar trees growing at sites 9 and 24 km northwest of the plant. 14C concentrations in tree rings from 2008-2014 (before and after the accident) were determined by accelerator mass spectrometry, with 14C activities in the range 231-256 Bq kg-1 C. A total of 5.5 TBq of 14C was released during the pre-accident period of 2008-2011. Activities during the period 2012-2014, after FDNPP shutdown, represent background levels, while the significantly higher levels recorded during 2008-2010 with excess 14C activities of 7.8-23 Bq kg -1 C, before the accident, indicate uptake of 14C from routine FDNPP operations. An effective dose commitment via food ingestion of up to 1.3 μSv was estimated from the excess activity of <23 Bq kg-1 C. The mean excess 14C activity for the pre-accident period at the sites 9 and 24 km northwest of the plant were 21 and 12 Bq kg-1 C, respectively, indicating that the area of influence during routine FDNPP operations extended at least 24 km northwest. The mean excess 14C activity in the 2011 ring at 24 km northwest of the FDNPP was 5.8 Bq kg-1 C, or about one-half of that at 9 km northwest (10 Bq kg-1 C). The decrease in 14C activities in 2011 rings with increasing distance from the FDNPP confirms that the possible impact of the FDNPP accident on 14C levels in trees. Keywords : Fukushima Dai-ichi Nuclear Power Plant; radiocarbon release; tree rings; effective dose
樹木年輪に記録された原発事故由来C-14の分布
松中哲也* '、笹公和'、松村万寿美'、平尾茂一'、脇山義史'、末木啓介' '金沢大学環日本海域環境研究センター ²筑波大学AMSグルーブ³福島大学環境放射能研究所*責任著者：matsunaka@se.kanazawa-u.ac.jp原子力発電所の稼働に伴って放出される14C (T1/2 : 5,730 yr)は、食物連鎖を通して内部被ばくに寄与する可能性のある核種として知られている。本研究は、福島第一原子力発電所から北西方向へ9 km地点と24 km地点に生育するヒノキとスギから採取した年輪（2008–2014年）の14C濃度を調査し、通常運転と事故によって放出された14Cの影響範囲を把握すると共に、食物摂取による年輪内14Cの実効線量を評価した。2008–2014年における年輪中の14C濃度は、加速器質量分析法により計測した結果、231–256 Bq kg-1 Cの範囲であった。14C濃度は、事故後の2012–2014年ではバックグラウンドレベルであったのに対し、2008–2010年（事故前）においてバックグラウンドより7.8–23 Bq kg-1 C高く、通常運転時に放出された14Cの取込みを示した。食物摂取による年輪内の余剰14C（<23 Bq kg-1 C）の実効線量は<1.3 μSv yr-1であり、自然放射線による平均実効線量（2.4 mSv yr-1）より３桁低かった。事故前における平均余剰14C濃度は、9 km北西地点で21 Bq kg-1 C、および24 km北西地点で12 Bq kg-1 Cであり、通常運転時に放出された14Cは少なくとも24 km北西地点まで影響を及ぼしていたことが分かった。2011年の年輪における24 km北西地点の平均余剰14C濃度は5.8 Bq kg-1 Cであり、9 km地点（10 Bq kg-1 C）のおよそ1/2であった。原子力発電所からの距離の増加に伴う2011年の余剰14C濃度の減少は、原発事故由来14Cの影響の可能性を示唆している。キーワード：福島第一原子力発電所、C-14放出、樹木年輪、実効線量
P-71
Elucidation of the cesium absorption and transport pathway of major
crops (rice and soybean).
Miku Kawabata ¹ , Ayano Amemiya ¹ , Jun Furukawa ² , Hiroki Rai* ¹ ¹ Akita Prefectural University ² Center for research in isotopes and environmental dynamics, University of Tsukuba *corresponding author：raihiro@akita-pu.ac.jp Radio-cesium (Cs) released by the accident at the Fukushima Daiichi nuclear power plant in 2011 contaminated the widespread soils. Radio-Cs was strongly adsorbed by soil. However, the plant roots uptake a part of it, causing radio-Cs contamination of agricultural products.In rice, it was revealed that OsHAK1, a high affinity K+ transporter, contributes the most of Cs+ uptake. In Tohoku region, the conversion of the paddy fields to soybean cultivation had been progressed due to the adjustment of an excess rice production. However, the Cs concentrations of soybean were higher than rice, and its mechanism of Cs uptake is unknown. We selected the four soybean mutants with low Cs (lcs) concentration in beans from the mutant lines induced by ion beam irradiation. In this study, we investigated the Cs uptake into the roots of the lcs mutants. The 2 weeks seedlings were transferred to three hydroponic solutions containing 137Cs as a tracer (containing 10 ppb 133Cs as a carrier) and K* at 0.05, 0.5, or 1.25 mM, respectively. In the lower K+ conditions, the 137Cs uptakes in wild type were higher. It was suggested that the K transporter is involved in Cs absorption.At 0.05 mM of K concentration, the 137Cs concentration in the roots in two lcs mutants was 1/2 and 1/3 lower than that of the wild type. The 137Cs in the remaining two mutants are as same as the wild type. And at above 0.5mM K+, there was no difference in 137Cs uptakes between lcs and the wild type. In conclusion, it was suggested that two lcs lines had mutations in the high-affinity K transporter in the root, and the remaining two lines had mutation in the process of Cs translocation from leaves to beans. Keywords : radio-Cs, soybean, high affinity K+ transporter, HAK
主要作物（イネ、ダイズ）のセシウム吸収・輸送経路の全容解明
河端美玖'、雨宮あや乃'、古川純'、頼泰樹* 1
¹秋田県立大学生物資源科学部²筑波大学アイソトープ環境動態研究センター *責任著者: raihiro@akita-pu.ac.jp 2011年の福島第一原発の事故による放射性セシウム（Cs）の土壌汚染が問題となっている。放射性Csは土壌に強く吸着するが、その一部は植物の根から吸収され、農産物の放射能汚染をもたらす。Cs+は、水稲ではK+輸送体であるOsHAK1から吸収されることが明らかになっている。東北各県では、米の生産調整に伴い、ダイズへの転作が進んできた。しかし、ダイズはイネより放射性セシウム濃度が高く、そのCsの吸収機構は未解明である。我々は、イオンピームで変異を誘発したダイズの変異系統から、子実のCs含有量が低い個体（lcs）を選抜した。本研究では、lcs変異体のCs動態を調べた。水耕液のK濃度を0.05、0.5、1.25 mMの3段階に調製し、137Csを添加してトレーサー実験を行った。その結果、K濃度が低いほど、野生型の137Cs吸収量が高くなり、Cs吸収にKの輸送体が関与していることが示唆された。また、0.05 mMのK濃度では、2系統で根の137Cs量が野生型の1/2、 1/3となった。残り２系統は野生型と同じ137Cs量であった。しかし、0.5mM以上のＫ濃度では、野生型との差はなかった。以上から、２系統は根の高親和性のK輸送体に変異があり、一方で、残り2系統は葉から子実へのCsの転流が抑制されていると予測された。キーワード：放射性Cs、ダイズ、K輸送体、HAK
P-72
Development of estimation method for genome alteration in wild
mice living in the Fukushima nuclear accident restricted area
Daiji Endoh* ¹ , Hiroko Ishiniwa ² , Misaki Tanaka ¹ , Manabu Onuma ³ , Nobuyoshi Nakajima ²
1 School of Veterinary Medicine, Rakuno Gakuen University ² Institute of Environmental Radioactivity, Fukushima University 3 Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies *Corresponding author: dendoh@rakuno.ac.jp In estimating genomic alteration in wild mice ( Apodemus speciosus ), mutations in the coding regions are the main observation targets. In this study, we examined a method for efficiently detecting alterations in exons, which are the coding regions of genes in the genome. Analyzing genome data registered in GenBank, the gene prediction software Augustus predicted 38,252 genes and 160,990 exons on the genome. For each exon, a nucleotide sequence including exon-flanking 70 bases was picked up and PCR primers were predicted. On the prediction, primers which having a high possibility for common-exon amplification were designed. A search for a 5-bases motif in the exons showed that 145,134 exons may be amplified using 51 pentamer motifs. Results on simultaneous amplification of multiple exons by PCR using 3’ end-motif sharing primers and base sequences using next-generation sequencer will be reported on the poster. Keywords : Apodemus, exon trapping, gene prediction, PCR primer design.
福島原発事故立ち入り制限区域における野生アカネズミの
ゲノム変化推定方法の開発
遠藤大二* '、石庭寛子'、田中美沙希'、大沼学'、中崎信美' '酪農学園大学獣医学群²福島大学環境放射能研究所³国立環境研究所生物・生態系環境研究センター *責任著者: dendoh@rakuno.ac.jp野生アカネズミのゲノム変化推定においては、遺伝子のコード領域の変化が主な観察対象となる。本研究では、 GenBankに登録されているゲノムデータを用い、遺伝子のコード領域であるエクソンの塩基配列変化を効率的に調べる方法を検討した。まず、遺伝子子測ソフトAugustusによりゲノムデータ上に38,252個の遺伝子と160,990個のエクソンを予測した。各エクソンについて、周囲配列70塩基を含む塩基配列を抽出し、共通してエクソンを増幅する可能性の高いプライマーの設計を実施した。共通増幅のために多くのエクソンで共有する3'末端の5塩基モチーフを探索したところ、51種のモチーフが145,134個のエクソンで増幅位置にあることが示された。現在、このモチーフの一部を用い、PCRによる複数エクソンの同時増幅と次世代シーケンサーによるエクソン塩基配列の決定を試みている。キーワード：アカネズミ、エクソントラッピング、遺伝子子測、PCRブライマー設計
P-73
Current occurrence of truffles and truffle-like fungi in forests after the Fukushima nuclear power plant accident Takamichi Orihara* ¹ , Hiromi Sasaki ² , Muneyuki Ohmae ³ , Hiroko Ishiniwa * ¹ Kanagawa Prefectural Museum of Natural History ² Mycologist Circle of Japan ³ Hokken Co. Ltd. 4 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: t_orihara@nh.kanagawa-museum.jp People in Fukushima have traditionally preferred eating wild mushrooms. Truffles and truffle-like fungi, which produce fruitbodies below ground or the litters, have often been neglected in mushrooms hunting, and in result, their local abundancy and species diversity have been poorly understood. In addition, since the forest management near the Fukushima No. 1 Nuclear Power Plant has been confronted with unprecedented difficulties, we consider that continuous monitoring of microbial diversity helps our understanding of environmental changes in local forests in that region. We therefore made a large-scale field survey of truffles and truffle-like fungi in secondary or artificial forests near the nuclear power plant (i.e., Kawamata, Namie, and Tomioka Towns and Kawauchi Village in Fukushima Prefecture) in July 2019. We collected 19 specimens of truffles and truffle-like fungi, which comprised at least 12 species of 9 genera in Basidiomycetes and Ascomycetes. The study sites in Namie Town and Kawauchi Village were particularly species- rich. We will further relate our results to the accumulation of radioactive cesium in these truffle specimens, which will be obtained from another project. Keywords : species diversity, hypogeous fungi, sequestrate fungi, taxonomy, radioactivity analysis
福島原発事故後の森林環境における地下生きのこ類発生状況調査
折原貴道* ¹、佐々木廣海²、大前宗之²、石庭寛子*
'神奈川県立生命の星・地球博物館²南類懇話会²株式会社北研‘福島大学環境放射能研究所*責任著者: t_orihara@nh.kanagawa-museum.jp福島県はきのこの食利用が伝統的に盛んだが、地中やリター層中にきのこを形成する菌類（地下生菌）については、一般的なきのこ狩りの対象になることも少なく、県内の地下生菌の多様性は十分に明らかでない。また、福島第一原発事故後、同原発周辺域の山林の維持管理は困難な状況であり、今後の森林環境の中長期的な変化を微生物多様性の観点からモニタリングしてゆく必要がある。本課題では、福島県川俣町、浪江町、富岡町、および川内村の二次林および人工林において、多数の地下生菌研究者による集中的な地下生菌探索を行い、原発事故後のこれら地域における地下生菌多様性を探ることを主な目的とした。7月に実施した野外調査の結果、担子菌門および子嚢菌門に含まれる少なくとも9属12種の地下生菌計19標本が採集された。特に浪江町津島および川内村の調査地での結果を合計すると12種全てが記録され、両サイトは特に高い地下生菌多様性を有する環境であることが示唆された。10月にも調査を実施予定であったが、大型台風の被害により中止を余儀なくされた。今後、本調査で採取された地下生菌を基にした放射線量測定プロジェクトとの統合的考察も進める予定である。キーワード：種多様性、地下生菌、分類、放射性セシウム
P-74
Population genetic demography of mountain stream fishes under reduced human activities in the difficult-to-return zones, Fukushima, Japan Yoshiaki Tsuda* ¹ , Masaki Akaike ² , Keisuke Yumoto ³ , Uchu Yamakawa ³ , Faulks Leanne Kay ¹ , Shingo Kaneko ' , Toshihiro Wada ' ¹ Sugadaira Research Station, Mountain Science Center, University of Tsukuba ² College of Biological Sciences, University of Tsukuba 3  Graduate School of Life and Environmental Sciences, University of Tsukuba 4 Faculty of Symbiotic Systems Science, Fukushima University 5 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: tsuda.yoshiaki.ge@u.tsukuba.ac.jp It is important to evaluate how reduced human activities in the difficult-to-return zones of Fukushima Prefecture affect local biodiversity in order to design ecosystem management strategies. In addition, as the difficult-to-return zones are located along the Abukuma mountains, which have a unique biogeographic history, unique patterns of genetic diversity and demographic history of species in this area are expected, and this information is highly valuable for understanding and conserving local biodiversity and genetic resources. In this study, we focus on the mountain stream fishes white- spotted char ( Salvelinus leucomaenis ) and yamame a landlocked salmon ( Oncorkyuchus masou ) and evaluate their genetic structure and infer population demographic history using maternally inherited mitochondrial DNA (mtDNA) variations. Moreover, we compared mtDNA genetic diversity of these species in and/or around the difficult-to-return zones with previous studies from other parts of Japan. So far, we detected one new mtDNA haplotype of white-spotted char around the difficult-to-return zones, highlighting the importance of local genetic resources. Further details of genetic structure and population demographic history will be discussed, as well as on-going work on biparental inherited nuclear DNA and the implications for the conservation of genetic diversity of species in Fukushima. Keywords : genetic diversity, demographic history, the difficult-to-return zones, Salvelinus leucomaenis, Oncorhynchus masou
帰還困難地域で人間活動が減少した環境下における渓流魚類の集団遺伝
学的動態の評価
津田吉晃* ¹、赤池真樹'、湯本景将'、山川宇宙'、Faulks Leanne Kay '、兼子伸吾'、和田敏裕' ¹筑波大学生命環境系・山岳科学センター菅平高原実験所²筑波大学生物学類³筑波大学大学院生命環境科学研究科4福島大学共生理工学類5福島大学環境放射能研究所*責任著者: tsuda.yoshiaki.ge@u.tsukuba.ac.jp人間活動が減少する帰還困難区域の設定が、自生の生物多様性にどのように影響するのか評価することは、これら地域の生態系管理の上でも重要である。特に独自の地史、生物史をもつ阿武隈高地麓に位置する帰還困難区域周辺では種の地域因有の遺伝的多様性や集団動態の歴史が期待され、これら情報は地域の生物多様性を理解し、地域の遺伝貨源保全を考慮する上でも重要な情報となる。本研究では渓流魚類、特にイワナ( Salvelinus leucomaenis )およびヤマメ( Oncorhynchus masou )に着目し、母性遺伝するミトコンドリアDNA(mtDNA)変異を用いて、これら種の遺伝構造および集団動態の歴史を評価した。さらにこれら２種について全国各地で報告されている先行研究も参考に、帰還困難区域周辺のイワナおよびヤマメのmtDNA変異を他地域と比較した。これまでにイワナでは先行研究で報告されていない新しいmtDNAハプロタイプが帰還困難区域周辺より検出された。さらに詳細な遺伝構造、集団動態、現在進めている両性遺伝する核DNA変異の結果も踏まえ、帰還困難区域周辺にみられるこれら魚種の固有な遺伝的多様性の保全の意味および意義について議論する。キーワード：遺伝的多様性、集団動態の歴史、帰還困難区域、イワナ、ヤマメ
P-75
Mechanisms of radiation effects mediated by secreted factors
Genro Kashino* ¹ , Kentaro Ariyoshi ² , Jun Kumagai ³
¹ Nara Medical University ²  Fukushima Medical University ³ Nagoya University *Corresponding author: kashino@naramed-u.ac.jp To elucidate the secreted factors that lead to radiation resistance, we clarified that there were factors that lead to radiation resistance in the culture supernatant of rat glioma cell C6 and attempted to identify them. The results showed that VEGF (angiogenic endothelial growth factor) increased dramatically during the time of radiation resistance acquisition. Furthermore, it was shown that cells to which recombinant VEGF was added became radioresistant and that treatment with axitinib, which inhibits activation of VEGF receptor, resulted in radiosensitization. The action of VEGF is suggested not only to promote angiogenesis in vivo, but also to lead to radioresistance as one of the factor involving cell-cell communication. Keywords : secretory factor, radioresistance, VEGF, cell-cell communication
分泌性因子を介した放射線影響の発現機構
菓子野元郎* '、有吉健太郎²、熊谷純³
¹奈良県立医科大学²福島県立医科大学³名古屋大学*責任著者: kashino@naramed-u.ac.jp我々は放射線抵抗性に導く分泌性因子を解明するため、ラットグリオーマ細胞C6の培養上清中に放射線抵抗性に導く因子があることを解明し、その同定を試みた。その結果、VEGF（血管新生増殖因子）が、放射線抵抗性獲得の時期に劇的に増えることを明らかにした。さらに、組換えVEGFを添加した細胞では放射線抵抗性になること、 VEGF受容体の活性化を阻害するaxitinibを処理すると放射線増感になることを明らかにした。これまで、VEGFの作用は、in vivoで酸素と栄養供給のために血管新生を促し、腫瘍組織などの放射線感受性に影響を及ぼすと考えられていたが、今回の結果は、VEGFが細胞間情報伝達の一つとして放射線抵抗性に導くシグナルの役割を果たすことを示している。キーワード：分泌性因子、放射線抵抗性、VEGF、細胞間情報伝達
P-76
Radiostrontium monitoring of fish bone from river ecosystem in
Fukushima
Zin'  ichi Karube* ¹ , Ryoichi Fujino ¹ , Takummi Nagami ¹ , Hirofumi Tazoe ² ¹  Faculty of Engineering, Kindai University ² Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: karube@hiro.kindai.ac.jp In this study, we investigated radiostrontium contamination using fish ( Salvelinus leucomaenis ) bone in Ukedo river ecosystem, Fukushima prefecture, Japan. Because fish bone has the property of accumulating radiostrontium in river water, we may be able to easily estimate radiostorontium contamination of river water or ecosystem from the activity of fish bone. Sampling was mainly undertaken in each site of Ukedo river basin (A: Omaru, B and C: Minamitsushima, D: Akougi) from 2015 to 2019. Activity of radiostrontium (90Sr) in fish bone in Site B and D was 21-144 Bq/kg wet, indicating higher activity than that in other sampling sites (8-12 Bq/kg wet). This result suggested to be radiostrontium contamination of fish and the river ecosystem (site B and D). In addition to 90Sr activity of fish bone, the activity of soil and river water in each sampling site showed higher activity in site B and D, similar to that of fish bone. These results suggest that 90Sr activity of fish bone would be good indicator of radiostrontium contamination of river ecosystems and a part of Ukedo river ecosystem is still contaminated by radiostrontium derived from Fukushima Daiichi Nuclear Power Plant accident. Keywords : radiostrontium, river ecosystem, fish bone
河川環境における魚の骨を用いた福島第一原子力発電所事故由来の
放射性ストロンチウム汚染の評価
苅部基一* '、藤野凌太郎'、永見拓夢'、田副博文²
'近畿大学工学部²弘前大学被ばく医療総合研究所*責任著者: karube@hiro.kindai.ac.jp本研究では、福島県浪江町の講戸川流域において、魚骨を用いて福島第一原子力発電所（原発）事故由来の放射性ストロンチウム（Sr）による陸水環境汚染の評価を行った。魚骨は河川水に含まれる低濃度の放射性Srを濃縮する特性があり、この骨の放射性Sr濃度から河川水や陸水環境全体における放射性Sr汚染の状況を推定できると考えられる。調査は2015年から継続しており2019年も主に請戸川流域内の複数地区（A：小丸、B・C：南津岛、D：赤宇木）で行った。各地点の魚骨中放射性Sr（90Sr）濃度は地点B・Dで21 ～ 144 Bq/kg wetと最も高くなり、B・Dの河川では原発事故による放射性Sr汚染の可能性があるといえる。同時に調査した土壌と河川水中のSr-90濃度も地点BやDで高い傾向があった。これらの結果は魚骨の放射性Sr濃度が陸水環境における放射性Sr汚染の指標となり得ること、請戸川流域の一部では今も原発事故の影響で放射性Sr汚染が続いていることを示している。キーワード：放射性ストロンチウム、河川環境、魚骨
P-77
Measurement and analysis of radioactive cesium in genitals of cats
captured in Namie Town, Fukushima Prefecture
Youhei Fujishima ¹ , Yasushi Kino* ² , Takumi Ono ² , Kentaro Ariyoshi ³ , Mitsuaki Yoshida ¹ , Kosuke Kasai ⁵ , Tomisato Miura 5 , Akira Nakata 6 ¹ Graduate School of Medicine, Tohoku University ² Department of Chemistry, Tohoku University ³ Integrated Center for Science and Humanities, Fukushima Medical University 4 Institute of Radiation Emergency Medicine, Hirosaki University 5 Graduate School of Health Sciences, Hirosaki University 6 School of Pharmacy, Hokkaido Pharmaceutical University *Corresponding author: y.k@tohoku.ac.jp After the evacuation of Namie residents due to the Fukushima nuclear power plant accident, pets and other animals left unavoidably wandered around the town. We collected genitalia isolated for castration and contraception of cats protected by a volunteer group in Namie Town, Fukushima Prefecture, and measured the radiocesium concentration. To date, there have been few studies in urban areas, and studies on the effects of radioactive materials in the living sphere and accumulation of data are complementary studies to the studies of raccoons, mice and Japanese monkeys, which are being conducted simultaneously. We analyzed the time course changes and distribution trends of radioactivity concentration in each area, and obtained trends in radioactive cesium uptake by animals living in the polluted environment after the accident. Keywords : radiocesium, cat, genitalia
福島県浪江町で捕獲されたネコの生殖器中放射性セシウムの測定と
分析
藤崎洋平'、木野康志*²、小野拓実'、有吉健太郎'、吉田光明'、葛西宏介'、三浦富智'、中田章' ¹東北大学医学研究科²東北大学理学研究科²福島県立医科大・総合科学教育研究センター *弘前大学被ばく医療総合研究所5弘前大学保健学研究科6北海道科学大学薬学部*責任著者: y.k@tohoku.ac.jp福島原発事故による浪江町民の避難の際、止むを得ず放置されたペットなどの動物は、その後町内を自由に徘徊していた。我々は、福島県浪江町内のポランティアグループによって保護されたネコの去勢・避妊のため摘出された生殖器官を収集し、放射性セシウム濃度を測定した。これまで市街地での研究例は少なく、生活圏での放射性物質による影響調査・データの蓄積は、同時に進めているアライグマ、アカネズミ、ニホンザルなどの調査と相補的な研究となる。地区ごとの放射能濃度の経時変化や分布の傾向について解析を行い、原発事故後の汚染環境に生息する動物の放射性セシウム取込みの動向を得る。キーワード：放射性セシウム、ネコ、生殖器
P-78
Age factors in uptake and excretion of radioactive material using raccoon
bone and cartilage
Yoshinaka Shimizu * ¹ , Takahashi Atsushi ¹ , Miura Tomisato ² , Shinoda Hisashi ¹ ¹ Graduate School of Dentistry, Tohoku University ²  Graduate School of Health Sciences, Hirosaki University *Corresponding author: shimizu@dent.tohoku.ac.jp Since bones and teeth take in radioactive materials during matrix formation, their use in investigation the exposure history of individuals has been studied. Bones unlike the teeth are expected to show changes in the accumulated amount due to remodeling in adult animals that have completed their formation, and may be affected by age-related changes in turnover. In this study, we examined the age-related change of radioactive materials taken in from outside. The material used a raccoon living in a high-dose area in Fukushima that was exterminated. Raccoons from Hokkaido were used as controls. The dose of raccoon was measured for quadriceps muscle and liver for Cs134 and Cs137 using a germanium semiconductor detector, and quantitative evaluation was performed using an imaging plate for teeth, bone and cartilage. The results showed a positive correlation between liver, muscle (Bq / kg) and teeth and bone (QL value). Furthermore, Cs concentration of muscle and liver, QL value of bone and tooth did not significantly correlate with environmental doses. Cartilage (in 3 cases) showed high value in the elderly racoon, but its elderly samples lived in high-dose areas. Although the age-related change in accumulation of radioactive materials was not clear, it is necessary to consider increasing the number of cases. Keywords : radioactive material, accumulation, age change, raccoon高線量地域に棲息するアライグマ骨および軟骨を用いた放射性物質の取り込みと排泄における加齢要因の検討清水良央* '、高橋温'、三浦富智'、篠田壽'
¹東北大学大学院歯学研究科
²弘前大学院保健学研究科*責任著者：shimizu@dent.tohoku.ac.jp骨や歯は、基質形成時に放射性物質を取り込むことから、個体の被曝履歴の検討に利用することが検討されている。骨は歯と異なり形成が完了した成獣個体では改造により蓄積量の変化を示すことが予測されるため、骨の代謝回転の経年的変化に影響を受ける可能性がある。本研究では、外部より取り込まれた放射性物質の経年変化について検討した。材料として苦獣として駆除された高線量地域に棲息するアライグマを用いた。対照として北海道のアライグマを使用した。アライグマの線量を大腿四頭筋、肝臓をゲルマニウム半導体検出器でCs134、Cs137を測定し、また歯、骨、軟骨はイメージングブレートで定量的評価した。結果は、肝、筋（Bq/kg）と歯、骨（QL値）は相関を示した。さらに筋、肝のCs遠度、骨、歯のQL値は環境線量と相関を示さなかった。軟骨（３例）は、高齢で高い値を示したが、高齢サンプルが高線量地域であった。加齢に伴う変化は明らかではなかったが、例数を増やして検討していく必要がある。キーワード：放射性物質、蓄積、加齢変化、アライグマ
P-79
Comprehensive analysis of radiation effect(s) in non-human primate
exposed in the ex-evacuation zone of the Fukushima Daiichi Nuclear
Power Plant accident Masatoshi Suzuki* ¹ , Satoru Endo ² , Yuki Matsutani ² , Yasushi Kino ³ , Takumi Ono ³ , Toshitaka Oka ⁴ , Atsushi Takahashi 5 , Yoshinaka Shimizu 5 , Hisashi Shinoda 5 , Tomisato Miura 6 , Kentaro Ariyoshi 74 , Mitsuaki Yoshida 6 , Manabu Fukumoto 8 ¹ International Research Institute of Disaster Science, Tohoku University ² Quantum Energy Applications, Graduate School of Engineering, Hiroshima University ³ Graduate School of Science, Tohoku University 4 Nuclear Science and Engineering Center, Japan Atomic Energy Agency 5  Graduate School of Dentistry, Tohoku University 6 Institute of Radiation Emergency Medicine, Hirosaki University 7 Integrated Center for Science and Humanities, Fukushima Medical University 8 Center for Advanced Intelligence Project, RIKEN *Corresponding author: masatoshi.suzuki.c7@tohoku.ac.jp Following the accident of Fukushima Daiichi nuclear power plant (FNPP), wild Japanese macaque chronically exposed to ionizing radiation in the ex-evacuation zone at low dose/low dose rate. We have collected the biological samples of 584 Japanese macaque since 2013 and establish the sample archive of non-human primate in order to analyze radiation effect(s). Dose and dose rate of Japanese macaque was evaluated using PHITS Monte Carlo simulation or ESR analysis of enamel samples. Both methods indicate that the external dose evaluated by our current system is reliable at above 200 mGy. We also found some molecular or cellular alterations, but not morphological alteration, which were elicited depending on the internal dose rate. Our findings indicate that radiation exposure by the FNPP accident continuously affects at molecular and cellular level, but does not lead to health effect so far. Keywords : Fukushima Daiichi nuclear power plant accident, radiation effect, non-human primate
福島原発事故に被災した野生ニホンザル生体試料を用いた包括的放
射線影響解析
鈴木正敏* ¹、遠藤暁’、松谷祐輝’、木野康志’、小野拓実’、岡藤崇’、高橋温’、消水良央’、篠田藤’、
三浦富智、有吉健太郎ﾌﾟ、吉田光明ﾟ、福本学* ¹東北大学災害科学国際研究所²広島大学院工学研究科²東北大学大学院理学研究科‘日本原子力研究開発機構原子力基礎工学研究センター 5東北大学大学院歯学研究科弘前大学被ばく医療総合研究所7福島県立医科大学総合科学教育研究センター 8理化学研究所革新知能統合研究センター *責任著者: masatoshi.suzuki.c7@tohoku.ac.jp 2013年から収集を開始した旧警戒区域に生息している野生ニホンザル試料を用いて被ばく線量評価と生物学的解析を行い、福島原発事故による放射線被ばく影響の解析を行った。PHITSモンテカルロシミュレーションによって野生ニホンザルに最適化した線量率換算係数を算出し、外部被ばくと内部被ばくについて評価した。PHITSシミュレーション以外にエナメル質のESR分析による外部被ばく線量評価を行い、200 mGy以上の線量域で両方法による評価結果が類似することを確認した。生物影響解析では、内部被ばく線量率に依存して変化する分子・細胞生物学的事象を明らかにした。その一方で、組織レベルで誘発される顕著な変化はこれまでに観察されていない。福島原発事故による低線量・低線量率放射線によって分子・細胞レベルでの影響が誘発されているが、組織レベルでの影響には及んでいないことが考えられる。
P-80
Development of method for evaluating transgenerational effects
focusing on meiosis
Akifumi Nakata 1 , Valerie Goh Swee Ting 2 , Kosuke Kasai 2 , Hirofumi Tazoe 3 , Kentaro Ariyoshi 3 , Hideaki Yamashiro 4 , Mitsuaki Yoshida 3 , Tomisato Miura* 2.3 ¹ Faculty of Pharmaceutical Science, Hokkaido University of Science ² Graduate School of Health Sciences, Hirosaki University ³ Institute of Radiation Emergency Medicine, Hirosaki University 4 Faculty of Agriculture, Niigata University *Corresponding author: tomisato@hirosaki-u.ac.jp The risk of carcinogenesis and transgenerational effects from chronic low-dose radiation exposure are important health impacts that should be considered. However, studies on reproduction and development after radiation exposure are scarce. Although radiation-specific chromosomal abnormalities in somatic cells can be detected easily, the chromosome morphologies of spermatids are more unclear as they show different chromosome morphologies in the various stages of meiosis. It is thus difficult to detect chromosome abnormalities in the germ cell. The objective of this study was to develop a new evaluation method to determine the effects of radiation on germ cells. We evaluated the feasibility of the cytokinesis-block micronucleus (CBMN) assay used in somatic cells, which detects chromosomal fragments induced by radiation, on germ cells. Ten-week-old male mice were exposed to total body irradiation of 2 Gy of X-rays. After irradiation, mice were sacrificed and testes were removed. The testicular cells were cultured in 10 % fetal calf serum/RPMI 1640 medium. After incubation for 44 h, cells were blocked from entering cytokinesis by the addition of cytochalasin B. After a total of 72 h incubation, the cells were fixed in 3:1 methanol/glacial acetic acid. The slides were scored blindly using a light optical microscope. We report the results of CBMN assay for different stages of meiosis and chromosomal aberrations in testis cells. Keywords : Germ cell, Meiosis, Cytokinesis-block micronucleus assay
減数分裂に着目した継世代影響評価系の開発
中田章史'、Valerie Goh Swee Ting ²、葛西宏介²、田副博文²、有吉健太郎'、山城秀昭'、吉田光明'、三浦富智* ²³ '北海道科学大学薬学部²弘前大学院保健学研究科³弘前大学被ばく医療総合研究所'新潟大学農学部*責任著者: tomisato@hirosaki-u.ac.jp低線量授性被ばくによる発がんのリスクと離世代影響が最も関心の高い生物影響であると考えられる。しかしながら、放射線の生物影響の解析において、生殖・発生に関する研究は乏しいのが実情である。体細胞では放射線特異的な染色体異常の検出が可能であるが、精巣細胞では、体細胞よりも染色体構造が不明瞭であり、減数分裂の様々なステージを経るため染色体形態も多様であることから、異常の検出が困難である。そのため、放射線による生殖細胞の影響は明らかにするためには新規の評価系の開発が必要不可欠である。本研究では、体細胞で利用されている放射線によって生じる染色体断片を検出する微小核アッセイ法を生殖細胞に対して適用可能かどうか検討した。X線を全身照射した雄マウスの精巣を摘出し、精巣細胞を培養した。細胞懸濁液をサイトスピン法によって標本を作成し、評価を行った。本法による減数分裂におけるステージ分類および精巣細胞における染色体異常について報告する。キーワード：生殖細胞、減数分裂、微小核アッセイ法キーワード：福島原発事故、放射線影響、野生ニホンザル
P-81
Effect of chronic radiation exposure associated with Fukushima accident on the freezability and fertility of the large Japanese field
mice (Apodemus speciosus) sperm
Hideaki Yamashiro* ¹ , Akifumi Nakata ² , Kosuke Kasai ³ , Kentaro Ariyoshi ¹ , Mitsuaki Yoshida ⁴ , Tomisato Miura ² 4 ¹ Faculty of Agriculture, Niigata University ² Faculty of Pharmaceutical Science, Hokkaido University of Science ³ Graduate School of Health Sciences, Hirosaki University 4 Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: hyamashiro@agr.niigata-u.ac.jp The objective of this study was to investigate the effect of chronic radiation exposure associated with Fukushima accident on the freezability and fertility of the large Japanese field mice ( Apodemus speciosus ) sperm. Male large Japanese field mice were captured from 2012 to 2018 in Fukushima Namie town. Female large Japanese field mice were captured at 2019 in Niigata city. Epididymal sperm collected from chronic radiation exposure large Japanese field mice were frozen in the ex-evacuation zone, and experiment was conducted to in vitro fertilization (IVF) with those of the cryopreserved sperm. The acrosome status of frozen-thawed sperm were also observed using FITC-PNA staining. IVF oocytes derived from cryopreserved sperm which frozen in 2012 to 2013 developed to 2-cell embryo. There were no differences between the development of the fertilised oocytes derived from either Fukushima cryopreserved sperm and control in vitro. Proportions of the acrosoeme of frozen-thawed sperm were also maintained. In conclusion, in vitro functional freezability, fertility of radiation exposure large Japanese field mice sperm were maintained. This suggested that the adverse radiation-induced effects were not observed in those of the sperm following chronic exposure. Further investigation on the effects of chronic radiation on the Fukushima derived large Japanese field mice sperm fertility should be continued. Keywords : large Japanese field mice ( Apodemus speciosus ), cryopreserved sperm, In vitro fertilization, fertility
被災アカネズミの凍結保存精子を用いた受精能の継時的評価
山城秀昭* 1 、中田章史2 、葛西宏介3 、有吉健太郎4 、吉田光明4 、三浦富智3 4
¹新潟大学農学部²北海道科学大学薬学部³弘前大学大学院保健学研究科³弘前大学被ばく医療総合研究所*責任著者: hyamashiro@agr.niigata-u.ac.jp生殖巣は放射線高感受性組織の一つであるが、精子形成過程ならびに初期発生過程におけるバイアスリスクにより、生殖・発生における放射線影響は不明な点が多い。従って、個体より得られる生体試料の解析に加え、自然の環境に制御されない、生殖工学技術を用いた評価も必要不可欠である。本研究では、2012年から福島原発旧警戒区域内で離続して採取・凍結保存している被災アカネズミ凍結保存精子を用いて、受精能に及ぼす影響を解析することにより、離時的な生殖機能を評価することを目的とした。雄アカネズミは2012年から福島県浪江町、雄アカネズミは2019年から新潟市の角田山にてシャーマントラップを用いて捕獲した。精子は、精巣上体から採取し、ストローに充填し、液体窒素にて凍結保存した。凍結融解後の精子の先体の染色は、FITC-PNA用いて蛍光染色を施した。卵子は、抗インヒビン血消（IASe)投与後、hCGを投与し採卵した。福島由来の凍結保存精子は、新潟アカネズミの排卵卵子と体外受精（IVF）を施し、その後の体外発生率を評価した。2012年から福島旧警戒区域内で捕獲した雄アカネズミにおいて、凍結融解後の精子の生存率は60%以上で保存することができた。凍結融解後の先体の正常性は、維持されていた。凍結融解後の福島由来精子をIVFした場合、高い割合で2細胞期までの発生が認められた。以上、IVFの実験は継続中であるが、2012年から2014年までに捕獲した被災アカネズミの精子は、正常に卵子に受精する能力を維持していたことが示された。キーワード：被災アカネズミ、凍結保存精子、体外受精、受精能
P-82
Annual dynamics of the biotransfer of radio-Cesium in forest ecosystem
Masashi Murakami* ¹ , Nobuhiro Ishii ²
¹ Chiba University ² National Institutes for Quantum and Radiological Science and Technology *Corresponding author: muramasa@facultychiba-u.jp A large amount of radionuclide was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Cesium rapidly binds to aerosols and is thus washed out by rain from contaminated air masses and deposited and accumulated on the land surface. Since most of the Japanese land area is covered by forest, the distribution and transportation of radionuclides within forest ecosystems should be conscientiously monitored. Within a forest, a diverse array of connections among species within complex food webs are formulated. Detritus based food chains are one of the main component of the forest ecosystems along with the grazing food chains based on plant production. To explore the biological proliferation of 137Cs within forest ecosystems, it is essential to track the 137Cs concentrations of each organism component within complex food webs. In the present study, the accumulations of 137Cs were monitored for each biological component of forest ecosystems, i.e., soil, fumes, plants, fungi, and animals. The trophic levels of these components were measured by the Nitrogen stable isotope (d15N) ratio of the samples. This was repeated for four times from 2012, one year after the accidents to 2017. The results of this analysis will be presented on poster. Keywords : carbon/nitrogen stable isotope, trophic levels, food webs, bio-proliferation, bio-accumulation
福島県の森林における放射性セシウムの生物移行の年次変化
村上正志* ¹、石井信昌²
¹千葉大学
²放射線医学総合研究所*責任著者：muramasa@faculty.chiba-u.jp環境水中に放出された放射性セシウム（137/134Cs）は、土壌や水の移動に伴って、非生物的に移動するのに加えて、生物に取り込まれることによって移動すると考えられる。さらに、生物間の食う食われるの過程、つまり、食物網を通じて、放射性セシウムは、高次の栄養段階へと生物拡散すると考えられる。今回の事故は、落葉樹林の開葉前の３月に起こり、放射性セシウムの環境中への放出は事故の初期に集中していたため、森林生態系において放射性セシウムは林床に最も多く付加された。したがって、森林におけるセシウム動態については、落葉からの洗い流しや溶脱、そして、分解を起点とした過程が影響すると考えられる。そこで、本研究では、福島県伊達市上小国地域の森林小流域において、森林土壌と落葉層、植物、菌類（キノコ）、そして、動物に含まれる放射性セシウムを定量した。さらに、窒素・炭素安定同位体比も測定し、これを、栄養段階の指標とした。これらのデータを事故の翌年の2012、さらに2013、2015、2017年に収集し、窒素安定同位体比と放射性セシウム濃度の関係の経年変化を確認した。その結果、栄養段階に伴うセシウム濃度には、負の相関があることがいずれの年でも見られた。これは、セシウムは生体内で生物濃縮しないという従来の知見を反映している。さらに、その傾きが、年を経るごとに増加する傾向が確かめられた。これは、事故により放出された放射性セシウムが、経年的に土壌等にトラップされ、生物に移行しにくくなっていることを示している。この傾向は2017年次点では収束しておらず、土壌におけるセシウムの不動化が進行中であることを示唆している。キーワード：炭茶・窒茶安定同位体、栄養段階、食物網、生物拡散、生物濃縮
P-83
Population genetic structure of Asian black bear in Fukushima
Prefecture
Yui Nemoto* ¹ , Rie Saito ¹ , Reiko Kumada ¹ , Natsuko Kondo ² , Yoshiki Morimitsu ³ , Masanori Tamaoki ² ¹ Fukushima Prefectural Centre for Environmental Creation ²  National Institute for Environmental Studies ³  University of Hyogo, Wildlife Management Research Center, Hyogo *Corresponding author: nemoto_yui_01@pref.fukushima.lg.jp Radionuclides were detected from the body of Asian black bear in Fukushima prefecture after TEPCO Fukushima Dai-ichi Nuclear Power Station accident. Large individual variation of radionuclide concentration in the same bear population was reported, and the migration between habitats was assumed as a reason why it. To show the migration of Asian black bear in Fukushima prefecture, we focused on population genetic structure of that bear population using DNA from the bears that was sampled for measurement of radionuclide concentration of the species. We extracted genomic DNA from 172 bears captured in Fukushima prefecture and 10 bears in Hyogo prefecture to estimate clear population genetic structure of the bears in Fukushima prefecture. Then, we analyzed population genetic structure of the bear population using these DNA samples. Keywords : Asiantic black bear, Ursus thibetanus, Fukushima, DNA, population genetic structure
遺伝子を用いた福島県におけるツキノワグマの地域間移出入の解明
と放射性核種汚染の関係
根本唯* '、斎藤梨絵'、熊田礼子'、今藤夏子'、森光由樹'、玉置雅紀' ¹福島県環境創造センター ²国立研究開発法人国立環境研究所³兵庫県立大学自然・環境科学研究所/兵庫県森林動物研究センター *責任著者: nemoto_yui_01@pref.fukushima.lg.jp東京電力福島第一原子力発電所事故後、福島県内のツキノワグマ体内から放射性核種が検出されている。ツキノワグマにおける放射性核種濃度は、同じ地域で捕獲された個体間でも大きく異なることが知られており、その原因の一つとして、捕獲された個体が、捕獲地域とは放射性核種汚染の程度が異なる地域から移入してきた個体である可能性が考えられる。そこで本研究では福島県内でのツキノワグマの移出入状況を把握するために、これまで福島県において放射性核種濃度を測定してきた個体の遺伝情報を用いて、福島県のツキノワグマにおける遺伝的集団構造を明らかにすることを目的とした。福島県において捕獲したツキノワグマ172個体、および、福島県内における集団構造を明確にするため、交雑の可能性が少ない兵庫県のツキノワグマ10個体からゲノムDNAを抽出した。これらのDNAを使用し集団構造を分析した。キーワード：ツキノワグマ、Ursus thibetanus、福島県、遺伝子、集団構造
P-135
The effects of farming interruption, decontamination and resumption on aquatic insects in the rice paddy fields by theaccident at the TEPCO Fukushima Daiichi Nuclear Power Plant Toshimasa Mitamura 1 , Wakana Endo 1 , Nobuhiro Matsuki 2 , Akira Yoshioka 3 , Ken Tabuchi 4 ¹ Fukushima Agricultural Technology Centre Hama-dori Centre, Japan, ² Fukushima Agricultural Technology Centre, Japan ³  National Institute for Environmental Studies 4 Tohoku Agricultural Research Center, NARO *Corresponding author: mitamura_toshimasa_01@pref.fukushima.lg.jp The Great North Eastern Japan Earthquake & Tsunami on March 11, 2011 inundated the coastlines of Fukushima prefecture and damaged many human lives and biodiversity. In addition, many residents were evacuated due to the accident at the Fukushima Daiichi Nuclear Power Plant. In these regions farming was interrupted. After that, the farmland was decontaminated and farming was gradually resumed. However, effects on biodiversity associated with farming interruption, decontamination and resumption were not examined in these farmlands. Therefore, in rice paddy fields where resumed, we investigated Odonata, the genus Sympetrum and damselfly (Coenagrionidae, Lestidae), aquatic Coleoptera and Hemiptera as the functional agro-biodiversity indicators(Mitamura et al. 2012). From the field research, three species of Sympetrum dragonflies, S. frequens, S. infuscatum, S. kunckeli were found in the paddy fields where farming resumed. Of these, S. frequens was the most common and the nymphal exuviae were found even in the reopening year. In the damselfly, 7 species (5 species of Coenagrionidae and 2 species of Lestidae) were found and the most common species was Ischnura asiatica (Coenagrionidae). On the other hand, 23 species of aquatic Coleoptera and Hemiptera were found in a 2019 survey. Coreoptera have 3 family 12 species, Hemiptera have 8 family 11 species. Among them, a large number of individuals were identified in Enochrus simulans (Coleoptera, Hydrophilidae), Gerris latiabdominis (Hemiptera, Geriidae) and Sigara nigroventralis (Hemiptera, Corixidae). Keywords : aquatic insect, rice paddy field, farming interruption, decontamination
東京電力福島第一原子力発電所事故後に営農再開した水田の水生昆虫
三田村敏正'、遠藤わか菜'、松木伸浩'、吉岡明良'、田口研'
'福島県農業総合センター浜地域研究所²福島県農業総合センター生産環境部³国立環境研究所福島支部4東北農業研究センター *責任著者：mitamura_toshimasa_01@pref.fukushima.lg.jp 2011年3月11日の東日本大震災に伴う福島第一原子力発電所の事故では、多くの住民が避難を余儀なくされ、これらの地域では、営農が中断された。その後、農地は除染され、徐々に農業が再開されている。しかし、これらの地域における生物多様性がどのように変化したのかは明らかではない。そこで、営農を再開した水田において、農業に有用な生物多様性の指標および評価マニュアル（2012）に従って、トンボ科アカネ属およびイトトンボ類、水生甲虫類および水生半翅類を調査した。その結果、アカネ属としてアキアカネ、ノシメトンポ、マイコアカネの３種が確認され、アキアカネが最も多く再開当年でも羽化殻が確認された。イトトンポ類では、7種が確認されアジアイトトンポが最も多くの地点で確認された。一方、水生甲虫類と水生半翅類では23種が確認された。その中では、キイロヒラタガムシ、ヒメアメンポおよびハラグロコミズムシで多数の個体が確認されている。キーワード：水生昆虫、水田、営農中断、除染
P-84
Precise and accurate measurement of uranium isotope ratios at
nanogram level using multi Daly collectors of MC-ICP-MS
Murugan Rajamanickam ¹ , Sarata Kumar Sahoo* ¹ , Tatsuo Aono ¹ ¹ National Institutes for Quantum and Radiological Science and Technology (QST) *Corresponding author: sahoo.sarata@qst.go.jp Uranium is primordial radioactive element present in the earth' s crust. Natural uranium comprises mixture of three isotopes such as 238U, 235U and 234U with relative isotopic abundances of 99.27%, 0.72% and 0.0055%, respectively. The chemical toxicity of uranium is likely to be much more important for human health compare to the risk of cancer from ionizing radiation. The principal modes of uranium intake are from food and water for occupationally unexposed persons. The concentration of uranium in Japanese rivers after FDNPP accident are range from 0.13 to 590 ng L-1 with the mean value of 54.7 ng L-1[1], which is three magnitude lower than World Health Organization (WHO) recommended value (30 μgL -1). Hence, the isotope ratio measurement of uranium on such low concentrated water samples are a challenging task. Multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is a powerful research tool for obtaining accurate and precise isotope ratios. MC-ICP-MS, Nu plasma 3D is equipped with five Daly detectors, six switchable 10 11 Ohm and 10 12 Ohm resistor Faraday cups, and two fixed 10 12 Ohm resistor Faraday cups, and eight fixed 10 11 Ohm resistor Faraday cups detector system. The multi-Daly detectors are used for such low concentration uranium isotope ratio measurement. The separated uranium fractions from JB-3 is made into four different concentrations such as 10 ngL-1, 25 ngL-1, 50 ngL-1 and 100 ngL-1 solution to find the working level of uranium in dry plasma condition of MC-ICP-MS. The precision obtained for 234U/238U and 235U/238U isotope ratios are in the range of 0.18% to 0.09% and 0.10% to 0.02% at two standard deviations (2SD) respectively. The accuracy of 234U/238U and 235U/238U isotope ratios with relative bias ranging from -0.16% to 0.07%, indicating that high accuracy is obtained for four different concentration using MC-ICP-MS [2]. Therefore, the present setup of multi-Daly in MC- ICP-MS coupled with desolvating nebulizer system can able to measure uranium isotopic ratio at ngL -1 level with high precision and accuracy. Keywords : uranium, Daly detector, MC-ICP-MS [1] S. Somboon, K. Inoue, M. Fukushi, H. Tsuruoka, H. Shimizu, S. Kasar, H. Arae, N. Kavasi, & S. K. Sahoo. J. Radioanal. Nucl. Chem. 319(3), 1307-1314 (2019). [2] J. Qiao, P. Lagerkvist, I. Rodushkin, S. S. Paatero, P. Roos, S. Lierhagen, K. A. Jensen, E. Engstrom, Y.  Lahaye & L. Skipperud. J. Radioanal. Nucl. Chem. 315(3), 565-58 (2018).
P-85
Analysis of in vivo kinetics of radiocaesium in Japanese Dace
Tribolodon hakonensis reared individually using CsI (Tl) scintillator
Masamune Endo*¹, Keiichi Sasaki¹,Tatsuma Sato¹, Tsuneo Fujita ¹ ¹Fukushima Prefectural Inland Water Fisheries Experimental Station *Corresponding author: endou_masamune_01@pref.fukushima.la.jp In conventional experiments using radiocaesium contaminated food, to elucidate the process of uptake of radiocaesium in fish, individual food intake could not reveal due to rear in groups. Therefore, the relationship between food intake and the amount of 137Cs accumulated in the fish was not clarified, since food intake and growth rate were different for each individual. On the other hand, food initial value of radiocaesium at the time when switching from radiocaesium- contaminated food to non-contaminated food was individual ly uncertain as radiocaesium in fish was measured in a dead state in previous studies. In this study, each daily food intake in Japanese dace was revealed by rearing individually, and the change of radiocaesium of a single specimen with the passage of time was clarified by measuring in vivo using CsI (Tl) scintillator. Furthemore, food initial value of radiocaesium at time when switching from radiocaesium –contaminated food to non- contaminated food was individually confirmed. The results is currently being compiled. Keywords : feeding experiment, 137Cs, food intake, individual rearing, CsI (Tl) scintillator
個別飼育及び非破壊式放射能測定器を利用したウグイ体内の放射性
Csの動態解析
遠藤雅宗* '、佐々木恵一'、佐藤太津真'、藤田恒雄'
'福島県内水面水産試験場
*責任著者: endou_masamune_01@pref.fukushima.la.jp魚類に放射性Csを含む餌料を与え、魚体中への放射性Csの移行状況を解析する試験は、従来、魚を集団で飼育していたため、個体ごとの摂餌量が掴めなかった。このため、個体ごとに摂餌量も成長量も異なる中で、摂餌量に対しての魚体への放射性Csの移行状況については、正確に把握できなかった。また、放射性Csを含む餌料から含まない餌料に切り替えて、魚体からの放射性Cs排出状況を解析する際に、従来は魚体を潰して放射性Csを測定していたため、個体ごとの放射性Cs量の初期値が不明であった。そこで、本試験では、ウグイを個体ごとに隔離して飼育し、個体ごとに毎日の摂餌量を正確に把握すると同時に、一定期間ごとに非破壊式CsI（TI）シンチレーションカウンター（以下、非破壊器）を用いて、活かしたまま魚体の時間あたりの放射性Csカウント数を測定し、飼育期間ごとの放射性Csの蓄積量の把握を可能とした。さらに、非破壊器の使用により、魚体からの放射性Cs排出状況を解析する際の個体ごとの放射性Cs量の初期値を得ることができた。結果の概要については、現在とりまとめ中である。キーワード：給餌試験、137Cs、摂餌量、個体別飼育、非破壊式y線測定器
P-86
Activity concentration of radiocaesium in self-consumed crops

Mihoko Kikuchi ¹ , Hirofumi Tsukada* ² 1 Graduate School of Symbiotic Systems Science and Technology, Fukushima University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: hirot@ipc.fukushima-u.ac.jp Returned residents living in cancelled evacuation-zone eat foods from not only markets but also kitchen gardens. The residents are advanced in age and they are having more self-consumed crops including wild vegetables and mushrooms than purchased food. In this study self-consumed crops made in Namie town where the evacuation order was released, wild vegetables, fruits, and mushrooms collected from nearby forest areas. Samples were provided from each household. The radioactivity concentration was accurately determined by a germanium semiconductor detector. It was measured and compared with the standard value of general food in Japan (100 Bq kg -1). Provided crops should be preprocessing. Collected crops samples were washed in order to remove soil and non-edible parts such as hides and seeds. The leaves and vegetables were dried at 70  °  C, and root vegetables and fruits with high sugar content were freeze-dried. The dried samples were pulverized with a stainless steel cutter blender and measured in a U-8 container for 70,875-109,795s. Soil samples collected at fields where the crops were grown was heat-dried at 50°C , then grinded in a mortar before being passed through a sieve and put and measured in a U-8 container for 1,106-3,754s. The activity concentration in leaves and vegetables were very low, 0.6-4.7 Bq kg -1 fresh weight, and those for root vegetables were 0.2-2.0 Bq kg-1 fresh weight. The native butterbur was 26 Bq kg-1 fresh weight. This is below the standard value. The soil was 294-977 Bq kg-1dry weight and decontaminated soil. The transfer factor from the soil to the crop was calculated and compared with the literature value. The transfer factor varied from 0.0012-0.0057 for leafy vegetables and 0.0006-0.0069 for root vegetables, was higher than the literature value. In the future studies, we plan to accumulate data on self-consumed crops including wild vegetables and mushrooms, and calculate the internal exposure dose. Keywords : cancelled evacuation-zone, self-consumed crops, preprocessing, transfer factor, internal exposure dose
避難指示解除後の自家消費作物の放射性セシウム濃度
菊池美保子'、塚田祥文* ²
¹福島大学大学院共生システム理工学研究科
²福島大学環境放射能研究所*責任著者: hirot@ipc.fukushima-u.ac.jp避難指示が解除された地域の住民は、市場に流通している食品以外に、除染された農地や家庭菜園などで自分たちが食べるための野菜（自家消費作物）を作り食している。帰還した住民で比較的高齢者である場合は、購入した食品よりも自家消費作物を食する傾向が高い。さらに栽培作物ばかりでなく、山菜やキノコなどを食することもある。本研究では、避難指示が解除された浪江町で作られた自家消費作物や、近くの山などで採取された山菜、果物、キノコ類を各家庭から提供いただき、ゲルマニウム半導体検出器で精密に放射能濃度を測定し、日本における一般食品の基準値(100 Bq kg 1)と比較した。提供された作物は、前処理として土などをよく洗い流し、皮や種などの可食部以外を取り除き、葉菜類は70℃で熱乾燥、根菜類や糖分が高い果物などは凍結乾燥し、デシケーターで乾燥確認後、カッタープレンダーで粉砕し、U-8容器で70,875 ～ 109,795秒間測定した。作物を育てている畑の土壌を50℃で熱乾燥し、節にかけた後に乳鉢で細かく砕き、U-8容器で1,106 ～ 3,754秒間測定した。その結果、葉菜類は0.6 ～ 4.7 Bq kg-1生、根菜類は0.2 ～ 2.0 Bq kg-1生と非常に低い値であった。自生のフキも26 Bq kg-1生と基準値を下回った。土壌は、 294 ～ 977 Bq kg-1乾燥で除染後の土壌であった。土壌から作物への移行係数を求め、文献値と比較した。移行係数は、葉菜類で0.0012 ～ 0.0057、根菜類で0.0006 ～ 0.0069とばらつきがあり、文献値より高い値を示した。今後は、山菜やキノコ類を含む自家消費作物のデータを蓄積し、内部被ばく線量を算出する。キーワード：避難指示解除、自家消費野菜等、前処理、移行係数、内部被ばく線量
P-87
Detection of 60Co released from the 2011 Fukushima Daiichi

Yusuke Okizawa ¹ , Hirofumi Tsukada* ² 1 Graduate of School of Symbiotic Systems Science and Technology, Fukushima University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: hirot@ipc.fukushima-u.ac.jp Various radioactive materials were released by the 2011 Fukushima Daiichi Nuclear Power Station (FDNPS) accident, and it was reported that 60Co, generated from 59Co by neutron in the cooling water, was detected in the soil collected from Namie in 2015. However, it has been not clear the distribution and release amount of 60Co in the environment. In this study activity concentration of 60Co in surface soils and humic substances collected from Okuma and Namie in 2016 and in 2011, where deposition of radiocaesium was relatively high areas around FDNPS and north-west direction from FDNPS, were determined. The samples were collected using a core sampler, and dried at 50 °C before being passed through a 2 mm sieve. The sieved samples were compressed into a plastic container (U-8) and measured 60Co at the energy peak of 1332 keV with a Ge semiconductor detector for 24,000-420,000 s. The 60Co was detected in four humus samples collected within 1 km from the southern direction of the FDNPS in 2016, and was not detected in the deeper soil layers under the humus. The deposition of 60Co at 1 km southern from FDNPS was 37-72 Bq m 2 , which was about 0.01% of the deposition of 137Cs. In the future studies, the 60Co measurement in archived soil samples collected from the northwest direction of the FDNPS, where the radiocaesium deposition was higher, will be measured. This study was performed using archive samples provided by the Nuclear Regulatory Agency and managed by the Institute for Environmental Radioactivity at Fukushima University. Keywords : neutron activation products, cooling water, 60Co
東京電力福島第一原子力発電所事故による60Co飛散の検証
沖澤悠輔'、塚田祥文* ²
'福島大学大学院共生システム理工学研究科²福島大学環境放射能研究所*責任著者: hirot@ipc.fukushima-u.ac.jp東京電力福島第一原子力発電所（FDNPS）の事故により放出された放射性核種には、冷却水に含まれている59Coが中性子照射を受け生成した60Coがあり、2015年に浪江町で採取された土壌から検出されたことが報告されている。しかしながら、環境中における60Coの分布、放出量などに関する研究はほとんど行われていない。そこで本研究では、 FDNPS周辺や2011年に採取されたアーカイブ土壌試料を用いて、比較的放射性セシウムの沈着が高かった大熊町や浪江町で採取された表層土壌や表層腐植物質中60Coを測定し、2011年の事故による60Co飛散の分布状況を検証し、放出量を予測することを目的として研究を始めた。試料は、コアサンプラーで採取し、50℃で乾燥した後２mmの篩を通しU-8容器に詰め、Ge半導体検出器で24,000 ～ 420,000秒計測し、1332 keVで60Coを定量した。FDNPSから南に１ｋｍの地点で2016年に採取した4試料の腐植から60Coを検出したが、その他の地点からは検出されなかった。腐植の下層土壌からは検出されず、 60Coの下方への浸透は認められなかった。採取地点における沈着量は37 ～ 72 Bq m ²であり、FDNPSのごく周辺での60Co沈着量は137Cs沈着量の0.01 %程度であった。今後、放射性セシウムの沈着量が高かったFDNPSから北西方向で採取されたアーカイブ土壌試料で60Coの測定を継続する計画である。本研究は、原子力規制庁が提供し、福島大学環境放射能研究所が管理するアーカイブ試料を用い行った。キーワード：中性子放射化生成物、冷却水、60Co
P-88
Radioactive cesium uptake in Koshiabura
(Eleutherococcus sciadophylloides)
Jun Furukawa* ¹ , Masaki Tamaoki ² , Takafumi Mizuno ³ ¹ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba ²  Fukushima Branch, National Institute for Environmental Studies ³  Faculty of Bioresources, Mie University *Corresponding author: furukawa.jun.fn@u.tsukuba.ac.jp It has been often reported that the radioactive cesium released from the Fukushima Daiichi Nuclear Power Accident is highly accumulated in the perennial mountain herb, Koshiabura ( Eleutherococcus sciadophylloides ), but its specific mechanism is not clear. Therefore, sampling of wild Koshiabura by field survey and analysis using plants cultivated in the laboratory were performed. A comparison of the radioactive cesium amount contained in the buds before development between Koshiabura and Taranoki ( Aralia elata), a mountain herb belongs the same family, sampled in the Iitate and the Yamakiya area in Fukushima prefecture showed that the cesium contained in Koshiabura buds was about 12-fold or 3-fold higher than that in Taranoki per fresh or dry weight, respectively. In order to elucidate the mechanisms of cesium absorption and accumulation in Koshiabura more in details, we are applying several growth conditions for establishing a cultivation system at the laboratory level using Koshiabura seeds. Keywords : radioactive cesium, Koshiabura ( Eleutherococcus sciadophylloides ), mountain herbs
コシアブラにおける放射性セシウム吸収特性の解析
古川純* ¹、玉置雅紀²、水野隆文³
¹筑波大学アイソトープ環境動態研究センター ²国立環境研究所福島支部²三重大学大学院生物資源学研究科*責任著者: furukawa.jun.fn@u.tsukuba.ac.jp福島第一原子力発電所の事故により放出された放射性セシウムが、多年生の山菜であるコシアプラに高濃度に蓄積されることが報告されているが、その具体的な機構についてはいまだ明らかではない。そこで現地調査による野生個体のサンプリングと、実験室において栽培された個体を用いた解析を実施した。福島県飯館地区と山木屋地区においてサンプリングされたコシアプラと、同じくウコギ科の山菜であるタラノキを用いて、それぞれの展開前の芽に含まれる放射性セシウム量を比較したところ、新鮮重量当たりでは約12倍、乾燥重量当たりでは約3倍の放射性セシウムがコシアプラの芽に含まれていた。より詳細な吸収ならびに寄锁機構を解明するために、種子から栽培したコシアブラを用いた実験室レベルでの栽培系の確立に向けて条件検討を進めている。キーワード：放射性セシウム、コシアプラ、山菜
P-89
Measurement and application studies on the environmental actinides
Z. Huang ¹ ² , Y. Ni ³ , H. Wang ⁴ , J. Zheng ∗ ¹ , S. Yamazaki ¹ , A. Sakaguchi ⁵ , X. Long ² , S. Uchida ¹ ¹ Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology ² Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics ³ School of Physics, Peking University 4 School of Nuclear Science and Technology, University of South China 5 Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: zheng.jian@qst.go.jp This work presents a method developed for simultaneous analysis of ultra-trace level 237Np and Pu isotopes in soil and sediment samples by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). 242Pu was used as a yield tracer for 237Np as well as for Pu isotopes. A simple single chromatographic column packed with anion exchange resin (AG MP-1M) was used for the separation of 237Np and Pu isotopes from the matrix elements and other potential interferences. The SF-ICP-MS measurement precision of the 237Np/242Pu atom ratio for sub-fg/mL level 237Np and 242Pu was 0.97%, and the overall fractionation between 237Np and 242Pu for the whole analysis procedure was 1.010 ± 0.038. Besides, the single column chromatographic separation realized high decontamination factor of U (1.8 × 10 6 to 1.7 × 107), and that ensured the interference effect of 238U to the 237Np, 239Pu and 240Pu measurements was negligible or could be easily corrected. Four standard reference materials were analyzed for method validation, and the results illustrated 242Pu was an effective non-isotopic tracer for 237Np determination. Finally, the developed method was successfully employed in the analysis of the global fallout level of 237Np and Pu isotopes in Japanese paddy soil samples to study their environmental behaviors. Keywords : SF-ICP-MS, Plutonium, Neptunium, global fallout
環境中のアクチノイド測定とその応用
Z. Huang ¹² , Y. Ni ³ , H. Wang ′ , J. Zheng ◦ ¹ , S. Yamazaki ¹ , A. Sakaguchi ⁵ , X. Long ² , S. Uchida1 '量子科学技術研究開発機構福島再生支援研究部²核物理・核化学研究所中国工学物理アカデミー ³北京大学物理学部'南華大学核科学技術学院5筑波大学アイソトープ環境動態研究センター *責任著者: zheng.jian@qst.go.jp本研究では、高分解能質量分析計を用いて、環境中の極欲量NpおよびPu同位体測定を行う手法の開発とその応用研究を行った。質量分析のための、環境試料マトリクスや妨害元素からのNpとPuの精製は、簡便かつ安価な除イオン交換樹脂(AG-MP-1M)を用いる事とした。また、ここでは、NpとPu両同位体測定のためにPu-242を収率トレーサーとして利用した。結果として、本研究で採用したシンプルな化学分離法では、環境試料中に大量に含まれる238Uの除去係数は1.8 × 106から1.7 × 107と高く、本研究で測定対象としている237Np, 239Puそして240Pu測定において、Uは無視できるくらい小さい、あるいは補正可能であることが確認されている。また、高分解能質量分析計（SF-ICP-MS）による測定において、237Npと242Puがそれぞれサプフェムトグラムオーダー (sub-fg/ml)の場合には、237Np/242Pu原子数比の不確かさは0.97%であり、測定の全工程から得られる237Npと242Puのフラクショネーションは1.010 ± 0.038と見積もられた。本研究で開発した方法を、4つの市販の標準物質に適応し、手法の妥当性を検討した。その結果、Np検出の際には242Puは非同位体トレーサーとして十分に利用可能であることが示された。また確率した方法で水田土壌中のグローバルフォールアウト由来NpとPu同位体組成を明らかにし、環境中におけるNpやPuの挙動に関して考察した。キーワード：SF-ICP-MS,ブルトニウム、ネブツニウム、グローバルフォールアウト
P-90
Precision analysis of tritium using low-background liquid
scintillation counter
Naofumi Akata* ¹ , Hirofumi Tazoe ¹ , Chutima Kranrod ¹ , Kenso Fujiwara ² , Toshiharu Misonou ² , Haruka Kuwata ² , Shigekazu Hirao 3 1 Radiation Chemistry Department, Institute of Radiation Emergency Medicine, Hirosaki University ²  Fukushima Environmental Safety Center, Sector of Fukushima Research and Development, Japan Atomic Energy Agency ³ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: akata@hirosaki-u.ac.jp In this study, low-background liquid scintillation counter (LSC-LB5, Hitachi) installed at Hirosaki University was employed in the evaluation of performance characteristics. The 50 mL of water sample was mixed with 50 mL of a liquid scintillation cocktail (Ultima Gold LLT, PerkinElmer, USA) in a 145 mL low diffusion polyethylene vial with an inner Teflon coating. After the vial was set in the liquid scintillation counter, counting time was performed for 1,000 min. As a result, background count rate was quite low at about 2.3 cpm, and minimum detection level (MDL) was approximately 0.29 Bq/L. In addition, enrichment factor of solid polymer membrane electrolytic concentrator-1 installed at Hirosaki University was 8.68, and MDL of combined with enrichment procedure was approximately 0.035 Bq/L. Keywords : tritium, low-background liquid scintillation counter
液体シンチレーションカウンターを用いたトリチウムの
精密計測に関する研究
赤田尚史* ¹、田副博文¹、Kranrod Chutima ¹、藤原健壮²、御園生敏治²、桑田遥²、平尾茂一² ¹弘前大学被ぼく医療総合研究所放射線化学部門²日本原子力研究開発機構福島研究開発部門福島環境安全センター ³福島大学環境放射能研究所*責任著者: akata@hirosaki-u.ac.jp本研究では、弘前大学に整備されている低バックグラウンド液体シンチレーション計数装置（LSC-LB5、日立）の性能評価を実施するとともに、因体高分子膜電解濃縮装置と組み合わせた際の定量下限価について検討を行った。測定は、試料水50mLに対し、シンチレーター 50 mLを混合し、装置内で1週間程度静置した後、1、000分測定を行った。その結果、バックグラウンドカウントは2.3 cpm程度と十分低いことが確認できた。この時の検出下限値はおおよそ0.29 Bq/Lであった。また、所有する固体高分子膜電解濃縮装置-1を用いて、初期水量800 mLから約60 mLまで濃縮した結果、トリチウム濃縮倍率は8.68であり、両者を組み合わせた際の定量下限値は0.035 Bq/L程度であった。キーワード：トリチウム、低バックグラウンド液体シンチレーション計数装置
P-91
Development of precise analysis Cs-134/Cs-137 ratio using thermal
ionization mass spectrometer
Hirofumi Tazoe* ¹ , Yoshitaka Takagai ²,³ ¹ Institute of Radiation Emergency Medicine, Hirosaki University ² Faculty of Symbiotic Systems Science and Technology, Fukushima University ³ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: tazoe@hirosaki-u.ac.jp Inventory of radioactive cesium isotopes (Cs-134, Cs-135, Cs-137) which generate by thermal neutron fission in the nuclear reactor   and its isotope ratios depends on type of nuclear fuel and burnup time. Radioactive decay also varies Cs isotope ratio with elapsed time because of their different physical half lives. Therefore, Cs isotope ratios can be useful tracer for the source. Cs isotope analysis using thermal inonization mass spectrometer (TIMS) is expected high precision, but removal of isobaric interference from barium (Ba) must be accomplished completely prior to TIMS analysis. In this study, improvement of Cs preconcentration and Ba removal has been examined. Cs in leachate from soil was preconcentrated by AMP. After dissolution in ammonium solution, Ba was removed by MnO2 resin and ion exchange chromatography. Keywords : thermal ionization mass spectrometer, Cs isotope ratio
表面電離型質量分析装置を用いた高精度Cs-134/Cs-137同位体比分析
田副博文* ¹、高貝慶隆²³
¹弘前大学被ばく医療総合研究所²福島大学共生システム理工学類³福島大学環境放射能研究所*責任著者：tazoe@hirosaki-u.ac.jp原子炉内で熱中性子核分裂反応により生成する放射性セシウム(Cs-134, Cs-135, Cs-137)の生成量や同位体比は燃料の種類や燃焼時間によって異なる。また、同位体ごとに物理学的半減期も異なるため、減衰によっても変化する。そのため、Cs同位体組成を調べることで供給源の情報を与える。表面電離型質量分析装置によるCs同位体比分析は精度の高いデータが得られることが期待されるが、装置自体ではバリウム（Ba）による同重体干渉を除去することが困難である。そのため、化学分離法を再検討し、Baの除去効率の向上を目指した。土壌抽出液からAMPにCsを吸着後、アンモニア水に溶解し、アイクロム社製MnO2レジンおよびイオン交換樹脂によりBaを除去した。キーワード：表面電繼型質量分析計、セシウム同位体
P-92
Fundamental research on tracer use of natural radionuclide
Masahiro Hosoda* ¹ , Shigekazu Hirao ² , Yuki Tamakuma ¹ , Naofumi Akata ¹ , Shinji Tokonami ¹ 1 Institute of Radiation Emergency Medicine, Hirosaki University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: m_hosoda@hirosaki-u.ac.jp Many papers about the tracer use of environmental radon have been published in the journal. Recently, an electrostatic collection type radon monitor (ERM-I) was introduced in the Institute of Radiation Emergency Medicine of Hirosaki University for tracer use of environmental radon. In this study, we carried out a calibration experiment of ERM-I using a radon calibration chamber which was developed by the Institute of Radiation Emergency Medicine. We obtained the conversion factor from counting rate to the radon concentration. We will carry out the further experiments to know the performance of the radon monitor. Keywords : natural radionuclide, tracer, radon monitor, calibration chamber
天然放射性核種のトレーサ利用に関する基礎研究
細田正洋* '、平尾茂一'、玉熊佑紀'、赤田尚史'、床次眞司'
¹弘前大学被ばく医療総合研究所
²福島大学環境放射能研究所*責任著者: m_hosoda@hirosaki-u.ac.jp天然放射性核種であるラドンは大気科学、地球科学、水文学などの分野においてトレーサ利用がされている。本研究では、弘前大学被ばく医療総合研究所に導入された静電捕集型ラドンモニタ（ERM-I）を本研究所に設置されているラドン較正場によって較正実験を実施し、計数値からラドン濃度への換算係数を評価した。今後、ラドンのトレーサ利用のために、湿度変化に対するERM-1の応答特性を評価する予定である。キーワード：天然放射性核種、トレーサ、ラドンモニタ、較正場
P-93
Feasibility of Cs-135 measurements using accelerator mass
spectrometry
Maki Honda* ¹ , Alexander Wieser ¹ , Johannes Lachner ¹ , Martin Martschini1, Peter Steier ¹ , Alfred Priller ¹ , Oscar Walther ¹ , Robin Golser ¹ , Keisuke Sueki ² , Aya Sakaguchi ² ¹ VERA Laboratory, Isotope Physics, Faculty of Physics, University of Vienna ²  Faculty of Pure and Applied Sciences, University of Tsukuba *Corresponding author: hondam84@univie.ac.at, m-honda@ied.tsukuba.ac.jp Transportation mechanisms of shorter-lived 137Cs (t1/2 =30.1 year) in the Fukushima area can be clarified by longer- lived fission product 135Cs (t1/2 =2.3 ×  106 year). Cesium 135 and 137 in the standard materials (137Cs source from Amersham UK, and grass of IAEA-372) and blank samples (Cs ICP Standard, Millipore) were measured by accelerator mass spectrometry (AMS) at University of Vienna to develop the 135,137Cs measurement. Cesium in ashed grass sample was leached using conc. HNO3 in the first step. Cesium in the acid leachate (pH<1) was next collected using 20 mg of AMP, and then remaining Cs in the acid leachate was collected using another 20 mg of AMP. This duplicated step led the good Cs recovery of 100%. Cs was more purified using 10 mL of cation exchange resin (Dowex 50W × 8, 100 – 200 mm, Alfa Aesar) in 9.5 mm i.d. PTFE column in the last step. The last step suppressed the amount of barium as <10 ng (1013 atoms) in Cs fraction (about 60 mL of 1 M HNO3). The AMS system sufficiently suppressed Ba signal by a factor of >108 (103 in the ion source and 104 in the ion cooler). Extraction of CsF2 –  beam from the mixed Cs2SO4, PbF2 and Cu powder sample was achieved by the fluoride sputtering with the current of 100 nA-1 µA. The intensity was 10 — 100 orders of magnitude greater than that of the Rb sputtering. The obtained 137Cs/Cs ratios in the blank samples were (3 − 6) × 10-12. Therefore, limit of detection was estimated to be 107 atoms, which corresponding to 13 mBq 137Cs and 0.17 μBq 135Cs. Our new method enables 135, 137Cs measurements with around 0.5 g of dried soil sample, and around 5 g of dried foods (brown rice, soy bean and mushroom). Keywords : 135Cs, accelerator mass spectrometry, Cs2SO4, CsF2-
加速器質量分析による放射性セシウム135の測定
本多真紀* ¹、Alexander Wieser ¹、Johannes Lachner ¹、Martin Martschini ¹、Peter Steier ¹、Alfred Priller ¹、 Oscar Walther ¹、Robin Golser ¹、末木啓介²、坂口綾² ¹ VERA Laboratory, Isotope Physics, Faculty of Physics, University of Vienna ²筑波大学数理物質系*責任者者: hondam84@univie.ac.at, m-honda@ied.tsukuba.ac.jp福島県内における137Csの移行過程を継続的に調査するために、半減期が更に長い135Cs (半減期2.3 × 106年)を137Csのブロキシとして利用する方法が新たに注目されている。化学処理手順の確立及び、測定性能の評価をするため、 137Cs標準線源(Amersham, UK)、IAEA-372 (Grass)、プランク試料(Cs ICP Standard, Millipore)を加速器質量分析(AMS)で分析した。酸抽出（灰分に1 mg Cs担体を添加して濃硝酸で抽出した）の後、Csの回収率を上げるために20 mg AMPによるCs捕集を2回行うこととした。これにより、Csは100%回収出来るようになった。陽イオン樹脂(Dowex 50W × 8、100 − 200 mm、Alfa Aesar)による更なるCs精製においては、内径9.5 mmのPTFEカラム、樹脂充填量10 mL、1M硝酸溶出で最終的に約60 mLのCsフラクション得た。この条件ではCsフラクション中のBaを<10 ng (10¹³ atoms)にすることができた。試料に残っているBaはAMSシステムで更に分離される。見積りではBaのsuppression factorは>108  （イオン源で103、負イオン減速チャンバーで104)である。一方でCsは、フッ茶でスバッタリングすることによってCsターゲット(Cs2SO4、PbF2、Cuの混合物)から100 nA − 1μA (CsF2−)の十分な電流が得られた。これはRbイオン源の10 − 100倍の電流に当たる。ブランク試料の137Cs/Csは(3 − 6) × 10-1²で、試料当たりの検出限界は107 atoms (13 mBq 137Cs、96 nBq 135Cs)と見積もられた。本方法では約0.5 gの乾燥土、約５gの食品（玄米、大豆、しいたけ）で135, 137Csの測定が可能である。キーワード：135Cs1、加速器質量分析、Cs2SO4、CsF2-
P-94
Monitoring of continental fallout in Okinawa Prefecture
Yoshitaka Shiroma * ¹ , Syunya Nakasone  ¹ , Shigekazu Hirao ²
1 University of the Ryukyus ²  Fukushima University *Corresponding author: y_shiro@cs.u-ryukyu.ac.jp The cosmogenic Berylium-7 (7Be, T1/2 = 53.3 d) were measured to understand the characteristics of continental fallout in Okinawa Prefecture. The atmospheric depositions were collected using a sampling basin (It is 800 mm in diameter and 300 mm in thick) at rooftop of the building of the University of the Ryukyus Faculty of Science from December 2019. Collected samples were passed through a column which was packed with ion exchange resin for collecting the various radioactive species. The resin was dried, followed by packing into plastic containers. 7Be concentrations in samples were measured by a high-purity Ge spectrometer for 250,000 sec, using   γ -rays of 477.6 keV for the determination. The characteristics of 7Be measured in Okinawa Prefecture will be report in the poster presentation. Keywords : Beryllium-7, atmosphere, cosmogenic
沖縄県における大陸起源の放射性降下物モニタリング
城間吉貴* ¹、仲宗根峻也¹、平尾茂一²
¹琉球大学²福島大学*責任著者: y_shiro@cs.u-ryukyu.ac.jp本研究では、沖縄県における大陸起源降下物の特徴を把握することを目的として、宇宙線生成核種である7Be (半減期：53.3日）の測定を行った。2020年12月から琉球大学理学部の屋上に直径800 mm・深さ300 mmの大型水盤を設置し、大気降下物の採取を行った。採取した試料は、陽イオン交換樹脂と陰イオン交換樹脂を充填したアクリルカラムに流して、樹脂に放射性核種を吸着させた。その後、乾燥処理を行い、プラスチック製容器に封入し、Ge半導体検出器を用いて250,000秒間測定した。7Be濃度の算出には、477.6 keVの全エネルギー吸収ピークを用いた。発表では、沖縄県において測定された7Beの特徴について報告する。キーワード：ベリリウム7、大気、宇宙線生成核種
P-95
Establishment of a novel cytogenetic dosimetry method using
chromosome condensation inhibitors
Yu Abe* ¹ , Mitsuaki A. Yoshida ² ¹ Department of Radiation of Life Sciencies, Fukushima Medical University School of Medicine, Fukushima, Japan. ²  Department of Radiation Biology, Institute of Radiation Emergency Medicine, Hirosaki University, Hirosaki, Japan *Corresponding author: abeyu@fmu.ac.jp The metaphase dicentric (Dic) assay is gold standard in cytogenetic biodosimetry and is the main aberration used for biodosimetry. For accurate assessment, the first metaphase chromosome image must be captured after prolonged colcemide treatment. However, the determination of Dic is made difficult by long-term colcemide treatment because of excessive chromosome condensation. Therefore, we focused on the regulation of chromosome condensation by mitotic kinase and attempted to control chromosome condensation by mitotic kinase inhibitors. First, we used the B lymphoblastoid cell line to determine the criteria for excessive chromosome condensation based on the arm length and width of chromosome 2. Next, we observed the change in the degree of chromosome condensation by the inhibitor, and added the inhibitor over time in parallel with colcemid treatment. As a result, some kinases including Casein kinase 2 tended to reduce excessive chromosome condensation. However, under multiple treatment conditions of the inhibitor, no more effect was observed than when the inhibitor was added alone. Excessive chromosome condensation was suppressed within 2 hours of the treatment with the inhibitor before the end of the culture. There are still many unclear points about the inhibitor treatment conditions. Therefore, it is necessary to clarify detailed conditions for preparing chromosome specimens for which Dic determination is easy. Keywords : dicentric chromosomes, chromosome condensation, mitotic kinase inhibitor
染色体凝縮阻害剤を用いた新規細胞遺伝学的線量評価法の確立
阿部悠* ¹、吉田光明²
'福島県立医科大学医学部放射線生命科学講座²弘前大学被ばく医療総合研究所放射線生物学部門*責任著者: abeyu@fmu.ac.jp二動原体染色体(Dic)法は、緊急被ばく医療における生物学的線量評価法のゴールドスタンダードであり、正確な被ばく線量評価を行うには、長時間のコルセミド処理で１回目の分裂中期染色体像を捉えなければならない。しかし、コルセミド処理時間が長くなるほど染色体が過度に凝縮しDicの鑑別が難しくなる。そこで我々は、染色体凝縮が分裂期キナーゼによって制御されていることに着目して、阻害剤による染色体凝縮制御を試みた。Bリンバ芽球細胞株で２番染色体を指標とした染色体過凝縮の評価基準について確認した後、細胞培養時にキナーゼ阻害剤を添加し、染色体凝縮度の変化を観察したところ、Casein kinase 2を始めとするいくつかのキナーゼで染色体の過凝縮緩和の傾向が認められた。次いで、阻害剤の組み合わせを変えて複数同時に添加した場合は、阻害剤を単独で添加した条件以上の過凝縮緩和は認められなかった。いずれも阻害剤処理は培養終了前の2時間以内の比較的短い処理時間で過凝縮緩和効果が認められたため、Dic鑑別が容易な標本作製条件について詳細な条件を明らかにする必要がある。キーワード：二動原体染色体、染色体凝縮、分裂期キナーゼ阻害剤
P-96
Analysis of temporal variations for Cs concentration and bio-aerosol
in Tsukuba botanical garden
Ishizuka Masahide*¹, Tanaka Kuniaki ² , Miyamoto Erika ¹ , Hatano Yuko ³ , Hosaka Kentaro ' , Kita Kazuyuki ⁵ , Maki Teruya  ,  Igarashi yasuhito 7 1 Kagawa University, Faculty of Engineering ² Kagawa University, Graduate school of Engineering ³ Tsukuba University, Center for research in isotopes and environmental dynamics 4 National Museum of Nature and Science, Department of Botany 5 Ibaraki University, Faculty of Science 6 Kanazawa University, Institute of Science and Engineering, 7 Kyoto University, Institute for Integrated Radiation and Nuclear Science *Corresponding author: ishizuka@eng.kagawa-u.ac.jp At the National Museum of Nature and Science, Tsukuba Experimental Botanical Garden, field observations were conducted in July 2019 to evaluate the conditions for the release of mushroom spores. A video camera, a thermo- hygrometer, and a particle counter were used for the observation. As a result, we succeeded in measuring spore release from three different mushroom growing in summer. It became clear that the amount of mushroom spore differs depending on each mushroom growth process. In addition, the body shape of Shiitake mushroom is converted into three-dimensional data, and a 3-D numerical simulation is performed to examine the transporting characteristics at the time of spore release. The spore fall within the range of about 1.5 m. This agrees with the referenced research  (Galante et al., 2011) . Keywords : mushroom, spore, FDNPP accident, particle Image velocimetry
筑波実験植物園におけるバイオエアロゾルとセシウム濃度の時系列
データ解析
石塚正秀* ¹、田中邦明'宮本えりか' 、羽田野祐子' 、保坂健太郎' 、北和之' 、牧輝也' 、五十嵐康人' ¹香川大学創造工学部²香川大学大学院工学研究科³筑波大学アイソトープ環境動態研究センター  4国立科学博物館・植物研究部5茨城大学理学部6金沢大学理工研究域'京都大学複合原子力科学研究所*責任著者: ishizuka@eng.kagawa-u.ac.jp国立科学博物館筑波実験植物園において、2019年7月にきのこ胞子の放出条件を算定するための現地観測を実施した。観測には、ビデオカメラ、温湿度計、バーティクルカウンタを用いた。その結果、夏季に成長するタマゴタケ、ニガイグチモドキ、ガンタケから胞子放出を計測することに成功した。きのこの放出量は、きのこの成長過程によってそれぞれ異なることが明らかとなった。また、シイタケの子実体を三次元データ化し、胞子放出時における飛散特性を調べるための数値シミュレーションを行い、胞子の落下範囲は約1.5 m以内であり、カサの下部や後背の流速変化をシミュレーションすることができた。この結果は、既往の研究結果（Galante ea al., 2011）と一致した。キーワード：きのこ、胞子、福島第一原子力発電所事故、PIV解析
P-97
Abundance and distribution of radioactive cesium-rich microparticles
released from the Fukushima Daiichi Nuclear Power Plant into the
environment
Ryohei Ikehara ¹ , Kazuya Morooka ¹ , Mizuki Suetake ¹ , Tatsuki Komiya ¹ , Eitaro Kurihara ¹ , Masato Takehara ¹ , Ryu Takami ' , Shinya Yamasaki ' , Satoshi Utsunomiya* 1 Department of Chemistry, Kyushu University, Japan ²  Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Japan *Corresponding author : utsunomiya.satoshi.998@m.kyushu-u.ac.jp To understand the dynamics of highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) to the surrounding environment at an early stage of the nuclear disaster in March 2011, "quantification of CsMPs (QCP)" method was applied to 20 surface soils around FDNPP. The number and radioactivity fraction (RF) of CsMPs plotted in the map reveal that the distribution can be classified to three regions; near-northwest (N-NW), far-northwest (F-NW), and southwest (SW), of which the number and RF of CsMPs are determined to be 40.1 – 154 /g and 19.2 – 33.3%, 24.3 – 64.8 /g and 36.7 – 37.4%, and 0.869 – 8.00 /g and 27.4 – 77.9%, respectively. The distribution is comparable to the trajectories of the plumes released from the afternoon of March 14 until late afternoon of March 15, 2011, indicating that CsMPs only formed during the period. Unit 3 is the most plausible source of CsMPs based on the analysis of the sequence of the release events. The lower RF values in N-NW indicate the influence of the subsequent plume only consisting of soluble Cs species afterwards due to precipitation. Consequently, the quantitative distribution map of CsMPs obtained in the present study was useful for understanding the dynamics of CsMPs as well as the potential risk assessment in residential area and environmental impacts derived from CsMPs. Keywords : radiocesium , CsMPs, Fukushima, distribution of CsMPs
高濃度放射性セシウム合有微粒子(Cesium-rich microparticle,CsMP)
の多角的精密分析に基づく炉内の情報と環境影響
池原遼平'、諸岡和也'、末武瑞樹'、小宮樹'、栗原英太郎'、武原政人'、高見龍'、山崎信哉'、宇都宮聡* 1
¹九州大学大学院理学研究院²筑波大学アイソトープ環境動態研究センター *責任著者: utsunomiya.satoshi.998@m.kyushu-u.ac.jp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「QCP法※」を原発周辺～福島県内の20の表層土壌に適用して、CsMPの個数と放射能奇与率(RF値：全Cs放射能に対するCsMPの放射能の割合）を放射能測定マップに上に示した。原発から近いところではCsMPの個数が多いにもかかわらずRF値は低く、水溶性セシウムの寄与が大きいことが分かった。北西方向では、CsMPと水溶性セシウムがどちらも寄与しています。これは９つの主要なプルーム（大気の流れ）のうちプルーム３と８の軌跡に相当する。一方、南西方向では放射能は低いが、RF価は80%程度と高い価を示した。これはブルーム2の軌跡に相当する。この結果からCsMPは2011年3月14日～ 15日にかけてのごく短い期間に形成されて放出されたこと、初期は3号機からCsMPが放出されたことが推定された。キーワード：放射性セシウム、CsMPs、福島第一原子力発電所、CsMPの分布
P-98
Local coordination structures of Sr in calcite and aragonite
Kazuya Tanaka* ¹ , Shinya Yamasaki ²
1 Advanced Science Research Center, Japan Atomic Energy Agency ² Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: tanaka.kazuya@jaea.go.jp Marine organisms were contaminated by radionuclides released into the Pacific Ocean from the Fukushima Daiichi Nuclear Power Plant. One of the released radionuclides, 90Sr, is accumulated into marine biogenic Ca carbonates such as shells and coral skeletons by substitution of Sr for Ca site. Most of coral species form aragonitic skeletons, while shells of bivalves are often composed of calcite. In general, Sr2+ is incorporated more in aragonite with 9-fold coordination Ca2+ site than in calcite with 6-fold coordination Ca2+ site. In this study, we investigated local coordination structures of Sr in the two carbonate polymorphs of calcite and aragonite using extended X-ray absorption fine structure (EXAFS) spectroscopy. We measured stable Sr concentrations of limestone (calcite) and coral (aragonite) samples and then their K-edge Sr EXAFS spectra. Analysis of EXAFS spectra indicated that the local coordination structures of Sr in calcite and aragonite were different while Sr was substituted for Ca site in both calcite and aragonite. Corals had Sr concentrations (~7000 ppm) one order of magnitude higher than limestones (200 - 500 ppm), which is attributed to the difference of local coordination structures of Sr incorporated into calcite and aragonite. Considering almost the same chemical natures of stable and radioactive Sr, radioactive Sr is also accumulated into aragonitic marine carbonates. Keywords : Sr, calcite, aragonite
カルサイト及びアラゴナイト中のストロンチウム局所構造解析
田中万也* ¹、山崎信哉²
'日本原子力研究開発機構原子力科学研究部門原子力科学研究所先端基礎研究センター ²筑波大学アイソトープ環境動態研究センター *責任著者: tanaka.kazuya@jaea.go.jp福島第一原子力発電所で発生した汚染水が海洋に放出された結果、様々な海洋生物が放射性核種により汚染された。中でも放射性ストロンチウムは、同族元茶であるカルシウムと類似の挙動をするため、貝類の殻・サンゴ骨格などの炭酸カルシウムに濃縮する。貝殻及びサンゴ骨格の多くはアラゴナイトから成るが、一部同質多形であるカルサイトから成る種も存在する。一般的に、６配位Ca²+サイトを持つカルサイトに比べて９配位Ca²+サイトから成るアラゴナイトの方がSr2+を取り込みやすいと考えられている。そこで本研究では、EXAFS（広域X線吸収微細構造）法を用いてカルサイトとアラゴナイト中の安定Srの局所（置換）構造を調べた。石灰岩（カルサイト）とサンゴ（アラゴナイト）は異なるEXAFSスペクトルを示した。EXAFSスペクトルを解析した結果、Srの局所構造がカルサイトとアラゴナイトでは異なることが示唆された。こうした局所構造の違いは、６配位と９配位のCa2+サイトのサイズの違いに起因していると考えられる。また、サンゴ(Sr濃度~7000 ppm)は石灰岩(Sr濃度200 – 500 ppm),に比べてSr濃度が一桁高いことはこうした局所構造によるものであると考えられる。安定Srと放射性Srは化学的にはほぼ同じ挙動をすることから、放射性Srもアラゴナイト構造を持つ生物性炭酸酸に濃縮すると考えられる。キーワード：ストロンチウム、カルサイト、アラゴナイト
P-99
Development of NORM sources for educational application
Takeshi Iimoto* ¹ , Hiromi Koike ² , Hasan Md. Mahamudul ² ¹ Division for Environment, Health and Safety, The University of Tokyo ² Graduate School of Frontier Sciences, The University of Tokyo *Corresponding author: iimoto.takeshi@mail.u-tokyo.ac.jp A thick 500-yen coin-shaped source can be created using a proprietary compression molding machine, using familiar substances of natural origin. Potassium chloride and kelp were molded by this machine, but some coffee and sinter collapsed, and oil oozed out from some sinter. In the development process, it was thought that factors related to stable molding were related to the moisture content of the material, the pressure for compression, the particle size of the powder. The moisture content was measured using a soil moisture meter. Those that could be molded had a moisture content of the order of 2%, and those that collapsed had a moisture content of less than 1%. As for the pressure, durability tests were conducted for potassium chloride and sinter by molding pressure with reference to the impact test of sealed radiation source. There was no difference on the durability of sinter in the various pressures, and it was found that 40 MPa or more was optimal for potassium chloride. In the budget year of 2019, we focused on optimizing the conditions for creating radiation sources of NORM, but in the next year we will proceed with quantitative analysis as radiation sources for the education application. Keywords : NORM source, radiation education
環境物質を応用した教育用自然放射線源の開発
飯本武志* '、小池弘美²、ハサンエムディーマハムドゥル² ¹東京大学環境安全本部²東京大学院新領域創成科学研究科*責任著者: iimoto.takeshi@mail.u-tokyo.ac.jp身近な自然起源の物質を用いて、独自に開発した圧縮成型機を用いることで厚めの500円玉型の線源が作成できる。塩化カリウム、昆布では成型ができたが、コーヒー、湯の花については崩れたり油がにじみ出るものがあった。この開発のプロセスで、安定的な成型に関する要因には、材料の水分率、圧縮時圧力、粉末の粒径等が関係があると考えられた。その確認のために、水分率は土壌水分計を用いて測定した。成型できるものは2％台、崩れるものは1％未満の水分率であった。圧力に関しては、塩化カリウム、湯の花について密封放射線源の衝撃試験を参考とした成型圧力別の耐久度試験を行った。潟の花は耐久度に差は見られず、塩化カリウムでは40MPa以上の圧力が最適であると判明した。令和元年度は線源作成条件の最適化に着目したが、次年度は放射線源としての定量的な解析を進める。キーワード：自然放射線源、放射線教育
P-100
Calibration test on instrument for natural radionuclides in the
atmosphere
Kazuki Iwaoka* ¹ , Yuki Tamakuma ² , Masahiro Hosoda ²³ , Naofumi Akata ² , Shinji Tokonami ² , ¹ National Institutes for Quantum and Radiological Science and Technology ² Institute of Radiation Emergency Medicine, Hirosaki University ³ Hirosaki University Graduate School of Health Sciences *Corresponding author: iwaoka.kazuki@qst.go.jp The quality assurance of instruments for natural radionuclides is important to correctly evaluate influences due to natural radionuclides. In this study, we performed a radon exposure test in the radon facility in Hirosaki University to validate the instruments for radon measurement. The devices were exposed to radon gas under stable conditions. The ratio of radon concentrations of the nominal value and the measured value (i.e., the nominal value/ the measured value) was 1.02. Keywords : atmosphere, natural radionuclides, radiation exposure
大気中放射性核種測定器校正のための曝露実験
岩岡和輝* ¹、玉熊佑紀²、細田正洋²³、赤田尚史²、床次眞司²
¹量子科学技術研究開発機構²弘前大学被ばく医療総合研究所³弘前大学大学院保健学研究科*責任著者: iwaoka.kazuki@qst.go.jp自然核種の影響を正しく評価するには、自然核種の測定機器の品質を担保する必要がある。本研究では、自然核種の影響の主要因であるラドンについて、その測定器の品質を担保するために、弘前大学の放射性ガス曝露施設を用いて曝露実験を行った。安定したガス濃度（濃度に大きな変化がない環境下）で曝露できた。曝露期間におけるバックグラウンド値を考慮した公称値の算術平均値と校正対象装置の指示値の算術平均値を単純に比較した値（指示値/公称値）は1.02であった。キーワード：大気、自然核種、放射線被ばく
P-101
Development of a gamma-ray radiation source by using a dual
nozzle type 3D printer
Takashi Saito* ¹ , Yuya Koike ² , Horofumi Tazoe ³ 1 Faculty of Comprehensive Human Sciences, Shokei Gakuin University ² School of Science and Technology, Meiji University 3 Instotide of Radiation Emergency Medicine, Hirosaki University *Corresponding author: t_saito@shokei.ac.jp A gamma-ray radiation source for accurately determining the radioactivity of samples of arbitrary shapes were developed by using a 3D printer and a 3D scanner. The development of a radiation source using a fused deposition modeling type 3D printer that has dual nozzles and can mix two types of filaments at an arbitrary ratio, the strength of a 3D printer filament made by mixing lead oxide was not stable. Therefore, the expected performance could not be acquired. However, by applying this method to a product made by mixing a natural radioactive mineral called "artificial hokutolite", we succeeded in non-destructively measuring radioactivity concentration by creating a source with the same geometry. Additionally, the authenticity of whether or not artificial hokutolite contained travertine derived from hokutolite could be confirmed. Keywords : 3Dpurinter, gamma-ray radiation source
2ノズルタイプ3 Dプリンタを利用したガンマ線測定用基準線源の開発
齊藤敬* ¹、小池裕也²、田副博文³
¹尚網学院大学総合人間科学系²明治大学理工学部³弘前大学被ばく医療総合研究所*責任著者: t_saito@shokei.ac.jp本研究は、近年低価格化・高精度化が進んでいる３Dプリンタ・３Dスキャナを用い、任意形状の試料の放射能を正確に求めるためのガンマ線測定用基準線源を開発することを目的としている。 ２つのノズルを持ち2種類のフィラメントを任意の割合で混合できる熱溶解锁層方式３Ｄプリンタ用いた基準線源の開発に関しては、酸化鉛を混入させて作成した３Ｄプリンタフィラメントの強度が安定せず思った通りのバフォーマンスが得ることができなかった。しかし、「人工北投石」と呼ばれる天然放射性鉱物を混入させ作成した商品を、本方法を応用して同じ幾何学的形状の線源を作成し非破壊で放射能濃度を測定することに成功した。これにより、非破壊で人工北投石に北投石由来の湯花が含まれているかの真贋を確かめることができた。キーワード：３Ｄプリンタ、ガンマ線基準線源
P-102
Development of evaluating radiation exposure dose in association with nuclear disaster by PHITS code into which mesh-type reference computational phantoms (MRCPs) is incorporated and MRCPs in represented with high quality of organ/tissues of human body. Minoru Sakama* ¹ , Takuya Saze ² , Naofumi Akata ² ¹ Radiological Science and Technology, Tokushima University, ² National Institute for Fusion Science, ³ Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: minorusakama@tokushima-u.ac.jp In this study, we have generally performed to make progress according to the initial working scheme of our research subjects as follows, 1. Evaluation of internal exposure dose associated with the cause of  SPM and PM which caught radioactive cesium (including cesium ball) of nuclear disaster in FDNPP, in addition external exposure dose occuried in the cause of their fraction which have subsided in the ground. 2. For simulation space of Monte-Carlo based PHITS code, we have constructed the human body voxel phantom to carriy out the evaluation of exposure dose and maintained the calculation environment that could cope with the big phantom data. 3. Improved calculation environment of PHITS has included the construction based on applying the MRCPs with high quality to the huma voxel phantom currently in use. Keywords : Monte-Carlo calculation, PHTS, MRCPs
高精細なMesh-type人体ファントムとPHITS計算を用いた原子力
災害に伴う被ばく推定評価法の構築
阪間稔* ¹、佐瀬卓也²、赤田尚史³ ¹徳島大学大学院医歯業学研究部放射線理工学分野，*核融合科学研究所, ³弘前大学被ばく医療総合研究所*責任著者: minorusakama@tokushima-u.ac.jp本研究では，以下に掲げた研究目的をもとに，研究計画通りに概ね進捗することができた。 1.原子力災害起因の放射性セシウム（セシウムポールも含む）を捕捉したSPM,PMによる内部被ばく線量の推定,さらに地面に沈降した成分からの外部被ばく線量の推定2.この線量評価を行うために，モンテカルロシミュレーション計算コードPHITSの計算空間へ,人体ポクセルファントムを配置して，その英大なデータによる計算負荷の少ない放射線輸送計算設定が可能な環境整備3.高精細なポリゴンMesh-typeリファレンス人体ファントムMRCPsを人体モデルに採用する新たな計算環境の整備1)については,PHITS計算機能におけるマイクロドジメトリー（[t-sed]タリー）とTrack Structureを組み込み,それらが有効的に作用していることを確認することができた。2)については、モンテカルロシミュレーション計算では，放射線一つ一つの振る舞いを順に、物理的な現象をモデル化条件に合わせて，膨大な計算を実行するため、計算時間が長いことが欠点となっている。そこに人体ボクセルファントムデータが加わると、計算時間がいっそう長くなる。この問題点を解決するために，計算機の並列化（メニーコア化）での一計算が必須となる。本研究では，既存の計算機環境だけではなく，Microsoftが提供するクラウドコンピューティングAzureを活用し，比較的安価なコストで簡易的なメニューコア化を図り，整備することができた。3)については，漢陽大学から提供されている高精細なポリゴンMesh-typeリファレンス人体データを，PHITS計算空間に取り込むことが可能であるか検証し、さらに，これに関連した四面体構造メッシュ・ジェネレタであるTedGenの活用についても検証を実施した。キーワード：モンテカルロシミュレーション計算、PHITS, MRCPs
P-103
Survey of radiation and earthquake disaster education for children who have not experienced the Great East Japan Earthquake, and search for optimal educational content Takuya Saze* ¹ , Minoru Sakama ² , Naofumi Akata i ¹ National Institute for Fusion Science ² Tokushima University ³ Hirosaki University *Corresponding author: saze.takuya@nifs.ac.jp About nine years have passed since the Great East Japan Earthquake, and there are an increasing number of people in Fukushima that have not experienced the disaster. The purpose of this research is to investigate the current status of radiation education and earthquake disaster education in Japan, identify the characteristics and issues, and propose optimal educational contents.  All of the science textbooks used by elementary school fifth and sixth grade students and junior high school first to third grade students (elementary school: 12 books at 6 companies, junior high school: 15 books at 5 companies), the Great East Japan Earthquake, radiation, nuclear power Investigations were made to see if any descriptions were made regarding the locations and their environmental impacts.  The publishers differed in the amount of description of each keywards, especially in the description of the environmental impact of the Fukushima nuclear disaster. Keywords : government authorized textbook, science education, education for disaster prevention, education guideline
東日本大震災を経験していない児童等に対する放射線・震災教育の
調査および最適な教育コンテンツの模索
佐瀬卓也* ¹、阪間稔²、赤田尚史³ ¹核融合科学研究所²徳島大学³弘前大学*責任著者: saze.takuya@nifs.ac.jp東日本大震災から約９年を経過し、福島県内でも震災を経験していない世代や、転動等で震災後に福島県に移住された保護者が増加している。本研究の目的は、東日本大震災を経験していない児童等に対して国内で現在行われている放射線・震災教育の状況を調査し、その特徴と課題を洗い出した上で、震災経験者と未経験者のギャップを埋める最適な教育コンテンツの模索と提案を行うことである。今年度は小学校5、6年生の及び中学校1 ～ 3年生で使用されている総ての理科検定教科書（小学校：6社12冊、中学校：5社15冊）について、東日本大震災、放射線、原子力発電所、及びそれらの環境影響に関する記述が為されているか調査を行った。出版各社において各項目の記述量に差があり、特に福島原子力災害における環境影響についての記述に差異がみられたキーワード：検定教科書、理科教育、防災教育、学習指導要領
P-104
Trouble shooting for ESR dosimetry of racoon teeth living in evacuation zone after Fukushima Daiichi Nuclear Power Plant accident - Identification of interfering factors- Atsushi Takahashi* ¹ , Toshitaka Oka ² , Kazuma Koarai ² , Hisashi Shinoda ' ¹ Graduate School of Dentistry, Tohoku University ² Japan Atomic Energy Agency *Corresponding author: at@dent.tohoku.ac.jp We are participating in a research project that investigates the effects of radiation on racoon living in evacuation zone after Fukushima daiichi nuclear power plants accident. When measuring the external dose of an individual using a biomaterial, electron spin resonance (ESR) dosimetry using tooth enamel is often applied. Although it is considered effective to determine the amount of external exposure to individuals by ESR method not only humans but also in wild animals, it cannot be successful in raccoons. The reason is that the ESR spectrum of racoon enamels is not a typical curve and cannot be fitted by the measurement program. Although several chemical treatment for enamels are recommended to remove interfering factors, acceptable spectrum of racoon enamel is not obtained even after these treatment. Therefore, it is necessary to know what factors interfere with ESR measurements using raccoon enamel. In this study, we determined the elements containing in the racoon enamel by inductively coupled plasma (ICP) and attempt to identify the interfering elements for ESR dosimetry using racoon teeth. Keywords : ESR, ICP, racoon.
福島第一原発事故後の環境に棲息するアライグマの歯におけるESR
測定を妨害する因子の特定とトラブルシューティング
高橋温* ¹、岡壽崇²、小荒井一真²、篠田壽平¹東北大学歯学研究科²日本原子力研究開発機構*責任著者: at@dent.tohoku.ac.jp我々は福島第一原発事故後の環境における被ばくの影響をアライグマを用いて検討するプロジェクトに参画している。ヒトの被ばく線量評価を歯のエナメル質を用いて行うESR計測法は、野生動物の線量評価にも適用できると考えられるが、アライグマにおいては線量評価ができない。その理由はアライグマのエナメル質のESRスペクトルが典型的な形をしていないからである。典型的なスペクトルを得るために推奨された化学処理を行うが、アライグマではそれでも典型的なスペクトルが得られない。そのため、アライグマの歯におけるESR計測を妨害する因子が何かを特定する必要がある。本研究ではアライグマのエナメル質をICPにより含有元素を測定し、妨害している元素の特定を試みた。キーワード：ESR、ICP、racoon
P-105
Analysis of volcanic activity and radon and progeny nuclide
concentrations in Sakurajima
Kenta Higuchi* ¹ , Masahiro Hosoda ² , Shinji Tokonami ² , Suminori Akiba ² ¹ Japan Health Care College ²  Hirosaki University ³ Kagoshima University Graduate School *Corresponding author: k_higuchi@nihoniryo-c.ac.jp To determine if there was an association between outdoor radon gas concentrations and volcanic activities, hourly average outdoor radon concentrations were measured at a monitoring post located 10 km south–southeast from Mt. Sakurajima during August 2003 to July 2007. During this period, Mt. Sakurajima was recorded to have erupted 145 times on 107 days. The geometric mean radon concentration at the monitoring post at hours with eruptions was 8.5 Bq m -3 , which was statistically significantly higher (P <0.001) than that (= 6.5 Bq m -3) at hours without eruptions, when the data were restricted to hours with no wind. On the other hand, during hours with wind, outdoor radon concentrations were not affected by the eruptions. Next, the effects of tail winds were examined. At hours without eruptions, a tail wind blowing at a speed of 10 m s -1 resulted in a radon concentration of 6.6 Bq m -3 , which was significantly higher (P <0.001) than that associated with a head wind with the same wind speed (6.2 Bq m -3 ). However, at hours with eruptions, outdoor radon concentrations were not increased by tail winds. In conclusion, radon gas was released from the soil into the atmosphere during the eruption of Mt. Sakurajima, possibly in response to the increased seismic activity. In addition, the findings suggest that volcanic ejecta from Mt. Sakurajima also contributed to the outdoor radon concentrations. Keywords : outdoor radon, Mt. Sakurajima, volcanic eruption
桜鳥の火山活動とラドン及び子孫核種濃度の解析
樋口健太* ¹、細田正洋²、床次眞司²、秋葉澄伯³
1日本医療大学²弘前大学³鹿児島大学大学院*責任著者: k_higuchi@nihoniryo-c.ac.jp屋外ラドン濃度と火山活動の関連性を疑いラドン濃度を測定した。その期間に桜島は107日間で145回の噴火回数を記録した。風のない場合、噴火があった時間帯の幾何平均ラドン濃度は8.5 Bq m -3で、噴火のない時間帯の場合よりも統計学的に有意に高い（P <0.001）(= 6.5 Bq m -3) 濃度であった。一方、風のある場合、屋外のラドン濃度は噴火の影響を受けなかった。追い風の影響を調べた所、噴火のない時間で、10 m s-1の速度で吹く追い風の時のラドン濃度は6.6 Bq m 3で、これは同じ速度で吹く向かい風よりも有意に高い濃度（6.2 Bq m-3）であった（P <0.001)。しかし、噴火のある時間では、屋外のラドン濃度は追い風によって増加しなかった。結論として、ラドンガスは桜島の噴火に関連して土壌から大気中に放出される可能性がある。さらに、桜島の火山噴出物が屋外のラドン濃度にも寄与していることが示唆された。キーワード：屋外ラドン、桜島、火山噴火
P-106
Examination of submarine groundwater discharge search method
by measurement of radon concentration in water
Masahide Furukawa* ¹ , Yoshitaka Shiroma ¹ , Masahiro Hosoda ² , Naofumi Akata* ² , Tetsuya Sanada* ³ , Shunya Nakasone* ¹ , Akinobu Ishimine* ¹ , Kaori Nakamura* ¹ , Shinji Tokonami ² ¹ University of the Ryukyus ²  Hirosaki University ³  Hokkaido University of Science *Corresponding author: m_furu@sci.u-ryukyu.ac.jp Radon (222Rn) in environmental water have been used as a tracer to understand the water cycle process on the Earth's surface. Although it is important for assessing the impact of landwater on the marine environment, the method of applying to the quantitative search for seepage of groundwater is not established. In this joint research, to understand the submarine groundwater discharge area of terrestrial source groundwater and quantitatively understanding the amount and spread of the spring water, using the coral reef area under Okinawa prefecture as a test field. The samples were collected from Ohdohama coast where have reported of submarine groundwater discharge in southern part of Okinawa Island. The radon concentrations were measured with liquid scintillation counter (Tri-Carb2910TR, PerkinElmer) and portable 222Rn monitor (RAD7, Durridge). Radon concentration in the water was ranged from 1.08 to 5.78 Bq / L, showing high concentrations around the groundwater seeping point and a declining tendency as the distance from the point. At several points along the shoreline from the groundwater discharge point, relatively high concentration levels (1.96 to 2.70 Bq / L) were observed, and the occurrence of terrestrial groundwater with a certain extent along the coast was confirmed. From the above, the outflow area of groundwater from land area to coastal area could be observed by measuring radon concentration in water. Keywords : radon in water, submarine groundwater discharge, groundwater, coral reef area, water cycle
水中ラドン濃度測定による海底湧水探索手法の検討
古川雅英* ¹、城間吉貴'、細田正洋'、赤田尚史'、真田哲也'、仲宗根峻也'、伊志嶺聡伸'、中村夏織'、床次眞司' ¹琉球大学²弘前大学³北海道科学大学*責任著者：m_furu@sci.u-ryukyu.ac.jp環境水中のラドン（222Rn）は、地球表層における水循環過程を知るためのトレーサーとして利用できるが、陸水の海洋環境への影響を評価する上で重要な「海底湧水」、つまり海底からの陸源地下水の湧出や浸みだしの定量的探索への応用については、手法が確立されているとはいえない段階である。本共同研究（研究組織）では、様々な高精度放射能測定技術を組み合わせることによって探索手法を開発し、波浪と河川の影響が比較的少ない沖縄県下のサンゴ礁域をテストフィールドとして、陸源地下水の海底湧出域の特定とその湧出量・拡散状況など、従来は情報が不足していた水婚環過程の定量的把握を試みる。本研究では、これまでに海底湧水の報告例のある沖縄島南部の大度浜海岸をフィールドとした。コンバクト塩分計（HORIBA, Salt-22）を用いて淡水湧出地点を推定し、その地点を中心に計10地点でサンプリングを行い、液体シンチレーションカウンタ（Tri-Carb2910TR, PerkinElmer）で60分間測定した。また、静電捕集型ラドン測定器（RAD7, Duridge）も用いて測定を行なった。その結果、水中ラドン演度は1.08 ～ 5.78 Bq/Lの範囲であり、淡水湧出地点周辺で高い濃度を示し、地点から離れるに従い減少する傾向を示した。一部、減少傾向の緩やかな地点がみられ、湧出した淡水の流路と推測された。また、淡水湧出地点から海岸線に沿う複数の地点では、比較的濃度レベルの高い値（1.96 ～ 2.70 Bq/L）がみられ、沿岸域に一定の広がりをもつ陸源地下水の湧出が示唆された。以上の結果をふまえ、陸水の海洋への影響について、水中ラドン濃度測定による定量的な評価手法の検討を今後も継続する計画である。本講演では、これまでに内陸地域で観測した水中ラドン濃度データを示し、内陸地域から沿岸地域にかけての水中ラドンの濃度分布についても示す。キーワード：水中ラドン、海底湧水、陸源地下水、サンゴ礁域、水循環
P-107
Study of the deposition situation by the isotope analysis of
environmental samples near the Fukushima Daiichi Nuclear Power Plant
Haruka Minowa* ¹ , Hideki Yoshikawa ¹ , Hirofumi Tazoe ² ¹ Radioisotope Research Facility, The Jikei University School of Medicine ² Institute of Radiation Emergency Medicine , Hirosaki University *Corresponding author: minowa@jikei.ac.jp The purpose of this study is to estimate the source reactor from environmental samples containing radioactive materials released by the Fukushima Daiichi nuclear accident. We plan to measure fission-derived nuclides from samples near the nuclear power plant by ICP-MS analysis. Prior to the experiment, we examined which nuclide to measure. From the Cs isotope ratio (134Cs / 137Cs) estimated from the burn-up of nuclear fuel, it is possible to discriminate between reactor No. 1 and others, but it is difficult to distinguish between reactor No. 2 and reactor No. 3. Other than Cs, we selected 234U, 238Pu, 241Am, etc. as fission-derived nuclides that may be able to distinguish between Unit 2 and Unit 3 from their isotope ratios. We are sampling environmental samples from difficult-return areas. Each nuclide would be measured in these samples. Based on the results, we will identify the source reactor, estimate the degree of contamination of each reactor from each unit, and attempt to estimate the deposition process. Keywords : environmental samples, isotope analysis, ICP-MS, source reactor
福島第一原子力発電所近傍の環境試料の核種分析による
沈着状況の解明
箕輪はるか* '、吉川英樹'、田副博文² '東京慈恵会医科大学アイソトープ実験研究施設²弘前大学被ばく医療総合研究所*責任著者: minowa@jikei.ac.jp本研究の目的は、福島第一原発事故により放出された放射性物質を含む環境試料から、起源原子炉を推定することである。原発近傍の試料からICP-MS分析により核分裂起源の核種を測定する予定である。分析に先立ち、測定核種の検討を行なった。核燃料の燃焼度から推定したCs同位体比(134Cs/137Cs)からは、1号炉由来とそれ以外の判別はできるが、2号炉と3号炉の区別は困難である。Cs以外で、同位体比から2号炉と3号炉が判別できる可能性のある核分裂由来核種として、検討の結果234U、238Pu、241Am等を選定した。現在、帰還困難区域からの土壌等の環境試料の採取を行なっており、これらの試料からそれぞれの核種を測定する。その結果から起源原子炉を同定し、各地点における各号炉由来物質の混入程度を見積もり、沈着過程の推定を試みる予定である。キーワード：環境試料、同位体分析、ICP-MS、起源原子炉
P-108
Method for checking the sensitivity of exhaust monitors at radiation
facilities using radon in the environment
Yumi Yasuoka* ¹ , Shinji Tokonami ² , Masahiro Hosoda ³ , Takeshi Iimoto 4 , Takahiro Mukai ²
¹ Radioisotope Research Center, Kobe Pharmaceutical University ² Institute of Radiation Emergency Medicine, Hirosaki University ³ Department of Radiation Science, Hirosaki University Graduate School of Health Sciences 4 Division for Environment, Health and Safety, The University of Tokyo 5 Department of Biophysical Chemistry, Kobe Pharmaceutical University *Corresponding author: yasuoka@kobepharma-u.ac.jp We examined whether activated-charcoal radon collectors (PICO-RAD) can measure indoor radon concentration levels to confirm the sensitivity of exhaust monitors at radiation facilities using radon in the environment. The World Health Organization (WHO) proposed a reference level of indoor radon concentration of 100 Bq m.3. Therefore, it was decided whether the PICO-RAD was effective as a screening measuring instrument for measuring the reference level, and we determined the screening value. The reference monitor of this experiment (DGM-101, an exhaust monitor manufactured by Hitachi, Ltd., was used as a radon monitor) and PICO-RAD were calibrated in a standard radon chamber. When measuring radon concentration, simple linear regression analysis with the reference monitor as a dependent variable and the PICO-RAD as an independent variable was obtained, a 99% prediction interval was calculated. When the value measured by PICO-RAD was 88.8 Bq m -3 (PICO-RAD screening value), it was found that the radon concentration certainly did not exceed 100 Bq m .3. When the value measured with the reference monitor was 70.8 Bq m -3 (reference screening value), it corresponded to the PICO-RAD screening value. Since the reference screening value exceeded 50% of the reference level, it was found to be effective as a screening measurement device. In the future, a similar experiment will be conducted using a radon measuring instrument as a radon monitor at a humidity of about 50%. Keywords : activated-charcoal radon collectors, PICO-RAD, screening value, radon
環境中ラドンによる放射線施設監視モニタの感度確認
安岡由美* ¹、床次眞司²、細田正洋³、飯本武志²、向高弘²
¹神戸薬科大学放射線管理室²弘前大学被ばく医療総合研究所³弘前大学大学院保健学研究科‘東京大学環境安全本部²神戸業科大学薬品物理化学研究室*責任者者：yasuoka@kobepharma-u.ac.jp環境中ラドンによる放射線施設監視モニタの感度確認に、活性炭型ラドン検出器（PICO-RAD）が室内ラドン濃度レベルをどの程度測定できるか検討した。そこで、PICO-RADがWHOの空気中ラドン濃度のリファレンスレベル100 Bq m -3を測定するスクリーニング測定器として有効かどうか判断し、スクリーニング値を求めることとした。本実験の基準器（日立製作所製放射線施設監視モニタDGM-101をラドンモニタとして使用）とPICO-RADを標準ラドン場で校正した。宝内ラドンレベルにおいて、ラドン濃度を変動させ、そのラドン濃度を基準器とPICO-RADで同時に測定した。基準器で測定したラドン濃度を独立変数とし、PICO-RADで測定したラドン濃度を従属変数として示し、99%予測区間を算出した。ラドンレベルが100 Bq m -3以下であることを十分担保できる値は、PICO-RADでは、88.8 Bq m 3で、それは基準器の70.8 Bq m 3  （スクリーニング値）に相当した。このスクリーニング値はリファレンスレベルの50％を超えているので、スクリーニング測定器として有効とわかった。今後、本格的なラドン測定器をラドンモニタとして用い、湿度50%程度で実施する予定である。キーワード：活性炭型ラドン検出器、PICO-RAD、スクリーニング値、ラドン
P-109
Development of pretreatment and analysis for environmental samples containing radiocaesium - Preliminary ToF-SIMS analysis of Cs isotope ratio in the microparticle - Hisaya Tagomori ¹ , Hidehisa Kawamura* ¹ , Keiichi kusano ² , Terumi Dohi ³ ¹ Kyushu Environmental Evaluation Association ² Inspection Development Co., Ltd ³ Japan Atomic Energy Agency *Corresponding author: Kawamura@keea.or.jp To investigate their spatial distribution and physicochemical properties of the radiocaesium-bearing micro particles (CsMPs), an efficient methodology for determine and analysis them is required. Here we focused on CsMPs from litters as they may affect the radiocaesium cycling in forest ecosystem. In this study we developed a method to determine CsMPs (mostly 1-10 µm sizes) from litters by combine digestion treatment and automatic particle analysis with FE- EPMA. In total it took up to 3 days for detecting one CsMP from huge amounts of mineral-like and metallic particles. In the ToF-SIMS analysis for Cs isotope ratios of CsMPs to understand their emission source as the next step, pretreatment for easily detecting micron-sized samples is needed. To solve this problem, FIB technique was used for Gallium marking formation around target sample. Preliminary Cs isotope ratios  (133Cs, 134 (Cs + Ba), 135Cs, 137 (Cs + Ba)) and their distributions of CsMPs were determined by applying these approaches. We developed pretreatment for microscopy and ToF-SIMS analysis of CsMPs. Keywords :  ToF-SIMS, Cs isotope ratio, radiocaesium-bearing micro particle.
Cs保持に関わる環境試料の前処理・分析手法の確立一ToF-SIMSを用い
たCs同位体比測定の検討
田籠久也、川村秀久* ¹、草野桂一²、土肥輝美行'一般財団法人九州環境管理協会²検査開発株式会社³国立研究開発法人日本原子力研究開発機構*責任著者: Kawamura@keea.or.jp筆者らは、森林生態系のCs循環に影響する可能性のあるリターに着目し、Cs量が比較的高いとされるCs含有粒子（CsMPs）の割合や特性を評価するため、それらの前処理・分析手法を検討した。粒径1~ 10 μm程度のCsMPについては、有機物分解と電子顕微鏡を組み合わせて数千～数万の土壌粒子を含むリター中から短時間（3日／ 1粒子）で特定可能とした。Cs同位体情報を得るための二次イオン質量分析法（ToF-SIMS）を適用する上では、数μ mレベルの試料探索が課題であった。そこで、集束イオンビームでCsMPの周囲にGaの目印を施すことで、ToF-SIMSによるCsMPの探索を容易にした。また、同試料のCs同位体（133Cs, 134 (Cs + Ba), 135Cs, 137 (Cs + Ba))スペクトルおよび二次元マッビングから各Cs同位体の分布情報を取得し、電子顕微鏡およびToF-SIMSを用いた微小試料の決定から同位体比測定までの一連の分析手法を確立することができた。キーワード：二次イオン質量分析法、Cs同位体比、Cs含有粒子
P-110
Mineralogical study of transporting radiocesium sorbed media
Hiroki Hagiwara* ¹ , Hiromi Konishi ²
¹ Sector of Fukushima Research and Development, Japan Atomic Energy Agency ² Faculty of Science, Niigata University *Corresponding author: hagiwara.hiroki@jaea.go.jp Identification of radiocesium sorbed minerals in sediments is important in view of adsorbed or desorbed mechanism between minerals and radiocesium in river water. Recently, the authors reported that not only micas but also mafic minerals could contribute toward the radiocesium migration in Fukushima river basin. In this study, we investigated crystal structure of hornblende in riverbed of mafic minerals using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) within Tomioka river. The results showed a part of surface on hornblende is altered to clay minerals. We also confirmed hornblende had cleavages and fractures which filling altered minerals inner part. This implies that these altered minerals could be contribute radiocesium adsorbing. Keywords : radiocesium, minerals
放射性セシウムの移動媒体についての鉱物学的研究
萩原大樹* ¹、小西博巳²
¹日本原子力研究開発機構福島研究開発部門²新潟大学理学部*責任著者: hagiwara.hiroki@jaea.go.jp河川堆積物中の放射性セシウムを吸着する鉱物種を特定することは、将来の鉱物との収脱着の観点から重要である。近年、著者らは福島県内の河川水系において、雲母鉱物だけでなく、有色鉱物にも放射性セシウムが吸着し、移動に寄与する可能性があることを報告した。本研究では、富岡川の河床土に含まれる有色鉱物のうち、特に角閃石の結晶構造を把握することを目的として、走査型電子顕微鏡（SEM）および透過型電子顕微鏡（TEM）観察を行った。結果、角閃石の表面の一部に角閃石が変質した粘土鉱物が含まれた。また、角閃石の内部には劈開や割れ目が確認され、これらの近傍にも変質した鉱物が充填していた。これらの変質鉱物が放射性セシウムの吸着に寄与する可能性が示唆された。キーワード：放射性セシウム、鉱物
P-111
Environmental behaviors of radioactive Cs studied by Cs DGT
Takumi Saito* ¹ , Masafumi Fukuoka ² , Kenso Fujiwara ³ ' Nuclear Professional School, School of Engineering, The University of Tokyo ²  Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo ³ Fukushima Environmental Safety Center, Japan Atomic Energy Agency *Corresponding author: saito@n.t.u-tokyo.ac.jp Environmental behaviors of radioactive Cs is crucial to predict long-term changes of its distribution in soil or river environments. It is known that Cs is selectively bound to micaceous minerals in nature and inert for chemical exchange reactions. Nevertheless, dynamics of labile fractions of Cs in a given environment if any must play an important role for its environmental behaviors, as it directly contributes to the mobility and bioavailability of Cs. In this study, we perform in-situ evaluation of the labile Cs in soil and aqueous environments of Fukushima Prefecture by diffusive gradients in thin films (DGT), which is a technique designed for the lability measurement of trace elements in nature. Two types of DGT devices, one for aqueous environments and the other for soil environments, were developed and their applicability for environments have been tested by laboratory experiments. With the developed devices we have revealed that the labile fractions of radioactive Cs In river environments exceeds the dissolved ones, suggesting that the desorption of Cs from suspended particles modulates its behaviors in river water. Meanwhile, in soils we have found that the distribution of the labile fraction of radioactive Cs is heterogeneous with particulate materials rich in labile Cs and that the proportion of the labile Cs in a soil column becomes large at the depth deeper than 5 cm from the surface. Keywords :
Cs用DGTデバイスを用いた放射性Csの環境動態評価
齐藤拓巳* '、福岡将史²、藤原健壮³ '東京大学大学院工学系研究科原子力専攻²東京大学大学院工学系研究科原子力国際専攻³日本原子力研究開発機構福島環境安全センター *責任著者：saito@n.t.u-tokyo.ac.jp森林や河川環境中での放射性Csの分布の変化を予測するためには，Csの環境動態の理解が不可欠である． Csは雲母様鉱物に選択的に吸着することが知られているが、その移行性、生物学的利用能は、このうち、液相中の共存陽イオンと容易に交換可能な成分（置換活性成分）の脱離挙動によって支配される。本研究では，微量金属イオンの置換活性な成分をサンプリングする装置であるDiffusive gradients in thin films (DGT)を用いて、福島県内の水環境,土壌環境中の137Cs置換活性成分をその場評価した．研究では，まず，水環境と土壌用のCs DGTデバイスを構築し，その環境適用性を評価した．その後，福島県の河川水，および，土壌環境に適用した．河川への適用結果から， 137Cs置換活性成分が溶存濃度を超え，137Csの動態が懸濁物質からの脱離によって規定されていることを明らかにした．また，土壌環境への適用結果から，137Cs置換活性成分が不均質に分布しており，置換活性成分を豊富に含む粒子状の土壌成分が存在することが分かった．また，深さ５cm以深で，置換活性成分の割合が増加することも明らかになった.キーワード：放射性セシウム，森林土壌，河川，動態，DGT
P-112
Evaluation of sorption condition of polyvalent metal ions by
multidimensional spectroscopic approach
Takayuki Sasaki* ¹ , Taishi Kobayashi ¹ , Kenso Fujiwara ² , Terumi Dohi ² , Kazuki Ijima ² ¹ Department of Nuclear Engineering, Kyoto University ² Sector of Fukushima Research and Development, Japan Atomic Energy Agency *Corresponding author: sasaki.takayuki.2a@kyoto-u.ac.jp Development of more reliable sorption reaction model is essential for estimating a behavior of radionuclide migration in the environment, which contributes to the safety assessment of waste disposal of contaminated soil and wastes. Observation by various spectroscopic methods is helpful to understand a chemical condition of metal ions sorbed on soil and host rock surface. The TEM-EELS and TEM-EDS methods were used in the present study. These have been applied to lighter elements, while very few studies for heavier metals. Therefore, Eu and Zr as analogs of tri- and tetravalent actinides were examined. After attaching powder samples Eu203, ZrO2 (oxide), and Zr(acac)4 (acetyl- acetone complex) on a copper grid, a thin layer of carbon was deposited to prevent charge-up. No peak except 'zero los’ in the spectrum was obtained for Eu oxide, since the particle size was too large and the electron transmission in the sample might be suppressed. Meanwhile, Zr oxide was a nanoparticle, so peaks for Zr and O were observed in the TEM-EDS spectrum, and the lattice image showed a ZrO2 single crystal. The EDS peaks of Zr(acac)4 were clearly observed, and also small sharp peaks in EELS were observed at the edges of Zr and O. Thus, the thinness of the sample was indispensable to obtain a better quality of spectrum. Keywords : TEM-EELS method, sorption condition, rare earth element, zirconium
多面的な分光学的手法による多価金属イオンの収着状態評価
佐々木隆之* '、小林大志'、藤原健壮'、土肥輝美'、飯島和毅'
¹京都大学大学院工学研究科
²日本原子力研究開発機構福島環境安全センター *責任著者: sasaki.takayuki.2a@kyoto-u.ac.jp汚染土壌や事故廃棄物の処分安全評価に資する放射性核種の地中移行举動を検討するには、収着反応モデル構築のための知見の蓄積が重要である。試料表面の収着元素の状態把握には、種々の分光学的手法による観察が有効である。本年度着目したTEM-EELS法およびTEM-EDS法は、元素の配位環境に関する局所情報を得ることができ、軽元素の感度が高いが、重元素での検討例は殆ど無い。そこで3・4価アクチノイドのアナログとしてのEuおよびZrを用いて、その適用可能性を検討した。粉末試料Eu2O3およびZrO2（酸化物）、Zr(acac)4（アセチルアセトン錯体）を銅製グリッドに付着させた後、チャージアップおよび飛散防止のためにカーポン蒸着した。Eu酸化物の損失スペクトルには、ゼロロス以外のビークが得られなかった。粒子サイズが大きく、またEuの損失エネルギーが1100eVと大きく、電子の透過が制限されたと推測される。Zr酸化物は100nm以下のナノバウダーである。TEM-EDSスペクトルにはZr、Oビークが見られ、格子像においてZrOz単結晶が観察された。一方、EELSスペクトルには290eVにZrのなだらかなエッジが確認されたが、OのK-edgeは見られなかった。Zr(acac)4では明瞭なEDSビークが得られ、EELSにおいてもZr、Oのedgeに小さいシャープなビークが観測された。以上より、良好なスペクトルを得るには試料厚みの調整が重要であることが示唆された。キーワード：TEM-EELS法、収着状態分析、希土類元茶、ジルコニウム
P-136
Method development and radioactivity analysis of strontium-90 in
environmental samples by ICP-MS
Chen Fei* ¹.² , Zhang Zhen ¹ , Jiao Ling ² , Tazoe Hirofumi ³ , Yang Guosheng ³ ' National Center for Occupational Safety and Health, National Health Commission ² Institute of Radiation Medicine, Chinese Academy of Medical Sciences ³ Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: chenf_irm@126.com 90Sr is a product of nuclear fission. It is present in significant amount in spent nuclear fuel and radioactive waste from nuclear reactors and nuclear fallout from nuclear tests. 90Sr is one of the most dangerous man-made radionuclides with a long half-life of 28 years. It has a high affinity to bone. Tea plants are easy to absorb 90Sr from soils in the growth process, and 90Sr in fallout is prone to contaminate the tea leaves as well. In order to investigate the radioactivity concentration of 90Sr, several kinds of tea samples collected from verious provinces of China were carbonized, ashed, digested and leached, and then samples were measured after 90Sr/90Y was separated by di(2-ethylhexyl)phosphate (HDEHP). The results revealed that the radioactivity concentrations of 90Sr in tea samples ranged from 0.28 to 3.78 Bq/kg, and the possible internal doses of 0.44 × 10-2 ~ 6.00 × 10-2 μ Sv contributed to each consumer, which were far less than the ICRP annual dose  limit of 1 mSv for the public. Besides, we have collected some soil samples in Namie Town, Fukushima prefecture. 90Sr radioactivity concentration were also measured, which ranged from 0.8 to 17.0 Bq/ kg. Keywords : strontium-90, tea samples; soil samples, radioactivity, internal dose
P-113
quantum chemical simulation
Study of stability of complexes containing radioactive metal ions using Tsugiko Takase* ¹、Kousei Wadayama ¹、Syunsuke Nakamura ¹、Dai Oyama ¹ 1 Faculty of Symbiotic Systems Science、Fukushima University *Corresponding author: ttakase@sss.fukushima-u.ac.jp Following the accident at the Fukushima Daiichi Nuclear Power Station, an attempt was made to "take in Cs + ions and Sr2 + ions into organometallic complexes and fix them to use them to remove radioactive metal ions contained in the environment." The fixation of radioactive metal ions with Prussian blue, "Cs resin", "Sr resin", etc. has been proposed. Among them, the stability of the complex containing the radioactive metal ion was studied by the quantum chemical simulation using the density functional theory (Gibbs free energy change: Δ G = -RT * ln (K)、K: chemical equilibrium constant、pKa = -log (K))、and attempts have been made to use it for molecular design of new metal complexes. In this study, the accuracy of estimation of free energy    Δ  G was improved by using measured data for proton and electron hydration energy, which were important issues in estimating     Δ G in solution. We report the results of comparing the pK of the deprotonation of the compound containing a carboxyl group (EDTA) estimated by simulation with the measured data. The possibility of fixing Cs ions using manganese formate compounds is also discussed. Keywords : DFT calculation,  organometallic complex, proton (electron) hydration energy
放射性金属イオンを含む錯体の安定性〜量子化学シミュレーションによる評価〜
高瀬つぎ子* '、和田山晃世'、中村俊輔'、大山大学
¹福島大学共生システム理工学研究科
*責任者者: ttakase@sss.fukushima-u.ac.jp福島第一原子力発電所の事故以降、「Cs+イオンやSr2+イオンなどを有機金属錯体に取り込こみ、固定化することにより、環境中に含まれる放射性金属イオンの除去に利用しよう」とする試みが行われ、ブルシアンブルーやCsレジン、Srレジンなどによる放射性金属イオンの固定化が提案されてきた。その中で、放射性金属イオンを含む錯体の安定性を密度汎関数法による量子化学シミュレーション(Gibbsの自由エネルギーの変化： Δ G = -RT*ln(K)、K:化学平衡定数、pKa = -log(K))用いて評価し、新規の金属結体の分子設計に利用しようとする試みを行われている。今回、溶液中で△ Gを推定する上での重要な課題であったプロトンのエネルギーや電子の水和エネルギーに実測データを用いることにより、自由エネルギー Δ Gの推計の精度を向上させることができた。シミュレーションによって推計されたカルボキシル基を含む化合物(EDTA)の脱プロトン化のpKを実測データと比較した結果について報告する。また、ギ酸マンガン化合物を用いたCsイオンの固定化の可能性についても報告する。キーワード：DFT計算、プロトン（電子）の水和エネルギー、有機金属錯体
P-114
Studies on nickel(II) and cobalt(III) complexes of an isomeric
polyazamacrocyclic chelator and its N-pendent derivative for the
application in radioactive waste decontamination
Tapashi G. Roy* ¹ , Saroj K.S. Hazari ¹ , Benu K. Dey ¹ , Debashis Palit ¹ , Lucky Dey ¹ , Zinnat A. Begum ² , Ismail M.M. Rahman 3 ¹ Department of Chemistry, University of Chittagong, Bangladesh ²  Venture Business Laboratory, Advanced Science and Social Co-Creation Promotion Organization, Kanazawa University, Japan 3 Instiute of Environmental Radioactivity, Fukushima University, Japan *Corresponding author: tapashir57@cu.ac.bd Radioisotopes of nickel (r-Ni: 59Ni, 63Ni) and cobalt (r-Co: 60Co) are produced in the structural steels of nuclear reactor vessels and internal components from neutron activation of corresponding naturally occurring stable isotopes. The primary concern with r-Ni or r-Co is in limiting the exposure to personnel working for decommissioning and dismantling nuclear reactors, primarily those are in service for more than 30 yrs. The current work aimed to evaluate the performance of chelators like shape-persistent macrocycles for the selective isolation of r-Ni or r-Co from the waste matrix. Macrocyclic complexes of Ni and Co with the N-pendent bis(cyanoethyl) derivative of an isomeric ligand isolated from reduced hexamethyl 14-membered tetraazamacrocycle, namely Me6[14]ane, using stable chemical analogs, were synthesized. The compounds have been characterized by spectroscopic methods as well as by magneto- chemical, and conductivity data. It is expected that further study on the efficiency of adsorption of the chelators on Ni(II) and Co(III) ions may open a new dimension in radiochemistry. Keywords : macrocyclic chelator; complexation, nickel, cobalt
P-115
Studies on the distribution and migration characteristics of actinides in
typical karst environment
Hai Wang* ¹ , Jian Zheng ² , Detao Xiao ¹ , Ming Liu ¹ , Xiangyang Luo ¹ ¹ School of Nuclear Science and Technology, University of South China, China ² Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology, Japan *Corresponding author: 2016000006@usc.edu.cn, wanghai451405249@gmail.com Groundwater in karst aquifers constitutes about 25% of drinking water sources globally. Soils on karst landscapes are typically thin, patchy and extremely fragile. It has been observed that the widespread existence of metal binding and transport by natural organic matter (NOM) in karst dripwaters. The vertical distributions of 137Cs, 239+240Pu and 241Am activity in soils from Hunan karst environment were investigated. The total inventory of 239+240Pu, 137Cs and 241Am was 134.5 Bq/m2, 2342.3 Bq/m2, and 39.4 Bq/m², respectively for the Hunan soil core (0-30 cm). The Pu inventory was apparently higher than the global fallout inventory (42 Bq/m²) within the 30° -40° N latitude band due to precipitation and vegetation types (forests). In terms of migration, the depth distribution was analyzed in detail and the subsurface Pu activity peak was observed. The scattered high activity values in the deep soil might be derived from bioturbation. The 241Am/239+240Pu activity ratios have no obviously change with depth increase, indicating that Am has similar migration behavior in soil with Pu. The activity ratio of 241Am/239+240Pu was higher than the global fallout value. This result suggests the underestimation of 241Am activity in global fallout based on the 241Pu/239+240Pu activity ratio during the global fallout peak year in the early 1960s. The 137Cs/239+240Pu activities ratio in surface soil was 23.48 ± 1.73 which was close to the global fallout value. The 137Cs/239+240Pu activities ratios decrease with increase soil depth. This phenomenon may be attributed to different migration mechanisms between plutonium and 137Cs, and further research is needed to elucidate the influencing factors for Pu and 137Cs migration in karst environment. Keywords : Pu isotopes, 241Am/239+240Pu activity ratio, karst environment, global fallout
P-116
Long-term prediction for collective radioactive particles by a bayesian advection diffusion equation Yusuke Uchiyama* ¹ , Yuko Hatano ² ¹ MAZIN Inc. ²  University of Tsukuba *Corresponding author: uchiyama@mazin.tech Collective radioactive particles exhibit spatiotemporal random dynamics.  To predict long-term behavior of the collective radioactive particles, we propose a Bayesian advective diffusion equation as an extension of existing model. For practical use, we derive parameter estimation and predicting methods of the proposed model. Keywords : collective radioactive particles, advection diffusion equation, bayesian model
ベイジアン移流拡散方程式による大気中の放射性物質拡散挙動の長
期予測
内山祐介* ¹、羽田野祐子* ¹株式会社MAZIN ²筑波大学*責任著者: uchiyama@mazin.tech放射性粒子の集団運動はランダムな時空間変動を示す．このような時空間変動の長期予測を行うことを目的に，従来から使用されている移流拡散方程式をベイジアンモデルに拡張した．提案モデルは従来の移流拡散方程式をベースにしたベイジアンモデルであるため,観測データが得られるごとに潜在変数として与えられる流速場の情報を更新することができる.このモデルに対して,観測データが得られた際のモデルバラメータ推定手法と,条件付き分布による将来挙動の予測手法を導出した.キーワード：放射性粒子の集団運動、移流拡散方程式、ベイジアンモデル
P-117
Application of radon and its decay products monitor using two-filter method as a monitor for airborne radionuclides under nuclear disaster Yu Igarashi * ¹ , Takeshi Iimoto ² , Masahiro Hosoda ³ ¹ Graduate School of Frontier Sciences, The University of Tokyo ² Division for Environment, Health and Safety, The University of Tokyo ³ The Institute of Radiation Emergency Medicine, Hirosaki University *Corresponding author: yu.igarashi@envsys.k.u-tokyo.ac.jp The purpose of this study is as the following two points. The first is to realize stable measurement of concentrations of radon and its decay products in air using one monitor by opening or closing the window of the first filter of radon concentration monitor based on two-filter method. The second is to develop an emergency monitoring method under nuclear disasters using this monitor, taking into account existing of radon and its decay products evaluated as environmental background. In the first year of this study, we tried to realize operational stability of the monitor for the first purpose, and selected a semiconductor detector to measure α / β -rays at the same time  as well as acquired its basic characteristics for the second purpose. In BY2020, we will investigate measurement loss due to the attachment of radionuclides particulate to the inner wall of the collection container for the first purpose, and will design a conceptual for the analysis of acquired data related for the second purpose. Keywords : two-filter method, radon & its decay products concentration, nuclear disaster, emergency monitoring
2フィルター法を用いたラドン族濃度測定器の原子力災害における空気中
放射性物質濃度測定への応用利用
五十嵐悠* ¹、飯本武志²、細田正洋³ '東京大学大学院新領域創成科学研究科²東京大学環境安全本部³弘前大学被ばく医療総合研究所*責任著者: yu.igarashi@envsys.k.u-tokyo.ac.jp本研究では以下の２点を研究目的とする。１点目は、２フィルター法をベースとしたラドン濃度測定器の１段目フィルルターを開閉することによる、単一測定器でのラドンおよび壊変生成物の空気中濃度安定測定の実現、２点目はこの測定器を用いて、環境BGとして評価されたラドン族濃度を考慮した、原子力災害時における緊急時モニタリング手法の開発である。研究初年度となる今年度は、前者のための当該測定器の運転安定性の確認と、後者のためのα / β線用半導体検出器の選定及びその基本的特性の取得を実施した。今後は、前者のための捕集容器内壁への粒子性放射性物質の付着による測定ロスについての検討、後者に関連した取得データ解析のための概念設計を実施する。キーワード：２フィルター法、ラドン族濃度、原子力災害、緊急時モニタリング
P-118
Thoron infiltration through filters used for diffusion-type radon-
thoron detectors
Yasutaka Omori* ¹ , Yuki Tamakuma ² , Takahito Suzuki ³ , Eka Djatnika Nugraha ³ , Miki Arian Saputra ³ , Masahiro Hosoda ³ , Shinji Tokonami ² ¹ Fukushima Medical University School of Medicine ² Institute of Radiation Emergency Medicine, Hirosaki University ³ Hirosaki University Graduate School of Health Sciences *Corresponding author: ys-omori@fmu.ac.jp Air infiltration through a filter depends partly on pressure difference induced in the filter, i.e., air-flow conditions of the outer air. Consequently, response of diffusion-type detectors to radon and thoron may vary with air-flow conditions surrounding the detectors. This effect may be significant for thoron measurement because half-life of thoron is shorter than that of radon. The present study aimed at examining response of diffusion-type detectors (RADUET and AlphaGUARD) to thoron with respect to wind speed using a thoron calibration chamber established in Hirosaki University. Response of RADUET to thoron increased monotonically with wind speed. Response of AlphaGUARD increased with wind speed, but it became constant in higher wind speed. Different trend of thoron response between RADUET and AlphaGUARD can be explained by conditions of flow induced by pressure difference in filters of these two detectors. For RADUET, laminar flow was induced in the filter in the examined range of wind speed, which means that rate of thoron infiltration into the detector increased with wind speed. For AlphaGUARD, laminar flow was induced in the lower range of wind speed, whereas the flow was changed to turbulent flow at higher wind speed in which rate of thoron infiltration into the detector did not depend on wind speed. Keywords : advection, diffusion-type detector, filter, laminar flow, thoron, turbulent flow, radon
ラドン・トロン拡散型測定器に使用される子孫核種除去フィルタの
トロン浸透率
大森康孝* ¹、玉熊佑紀²、鈴木崇仁²、Eka Djatnika Nugraha ³、Miki Arian Saputra ³、細田正洋³、床次眞司等'福島県立医科大学医学部²弘前大学被ばく医療総合研究所³弘前大学大学院保健学研究科*責任著者: ys-omori@fmu.ac.jpフィルタの空気浸透特性はフィルタ間の差圧、すなわち外気の流動性に依存する。このため、付属する子孫核種除去フィルタによりラドン・トロンのみを弁別して検出器へ導入する拡散型ラドン・トロン測定器では、測定価は外気の濃度の他に外気の流動性に依存すると考えられる。特に、半減期が短いトロンではその影響が大きいと子想される。そこで、弘前大学に設置されたトロンチャンバーを用いて拡散型測定器（RADUETおよびAlphaGUARD）の曝露実験をおこない、トロンチャンバー内の風速と測定器のトロンへの応答の関係を調べた。その結果、RADUETの応答は風速の増加に従って単調に増大した。一方、AlphaGUARDの応答は、低風速域では風速の増加に従って増大したが、高風速域では一定であった。両測定器の異なる応答は、フィルタを浸透する流れ（移流）の形態が、RADUETおよび低風速域のAlphaGURADでは層流が卓越し、高風速域のAlphaGURADでは乱流が卓越していることを示唆する。キーワード：移流、拡散型測定器、層流、トロン、フィルタ、ラドン、乱流
P-119
Analysis of nonvolatile nuclides in radioactive particles released from
Fukushima Daiichi Nuclear Power Plant accident
Junya Igarashi* ¹ , Jian Zheng ² , Zijian Zhang ¹ , Kazuhiko Ninomiya ¹ , Yukihiko Satou ³ , Miho Fukuda ² , Youyi Ni ² 4 , Tatsuo Aono ² , Atsushi Shinohara 1 ¹ Graduate School of Science, Osaka University ²  Department of Radioecology and Fukushima Project, National Institutes for Quantum and Radiological Science and Technology ³ Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency 4 State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University *Corresponding author: igarashij17@chem.sci.osaka-u.ac.jp The radioactive particles having highly concentrated radioactive Cs were released into the environment by the accident of Fukushima Dai-ichi Nuclear Power plant. Due to its insolubility, the radioactive particles have still been retaining the original property such as elemental composition at the time of emission from the reactor. Cesium-137, 90Sr and 239, 240Pu are the most remarkable radioactive nuclides due to their long half-lives and large core inventories. These nuclides having different volatile behaviors according to the oxidization potential in the reactor. Therefore, by analyzing the elemental composition of radioactive particles, the progress in the reactor at the accident can be investigated. In this study, we picked up 4 radioactive particles from dust and soil samples collected in Futaba and Okuma town. After measurement of gamma-rays from 134, 137Cs by germanium detector, we separated 90Sr, 239Pu and 240Pu by radiochemical analysis and identified them by Cherenkov light and ICP-MS measurements. By analyzing radioactivity ratio of 134Cs/137Cs, the particles were estimated to be derived from Unit1 and Unit 2 or 3. For the radioactive particle derived from Unit 1, the activity ratios of 90Sr/137Cs and 239+240Pu/137Cs were about 10-4 and 10-8, respectively. For the radioactive particle derived from Unit 2 or 3, the activity ratios of 90Sr/137Cs were equivalent to the value of radioactive particles derived from Unit 1. However, the activity ratios of 239+240Pu/137Cs in the radioactive particles derived from Unit 2 or 3 were clearly lower than the value of radioactive particles derived from Unit 1. This difference indicated the different formation process among these radioactive particles, such as temperature and oxidation potential in the reactors. Keywords : radioactive particle, radiochemical analysis, ICP-MS, strontium, plutonium
福島原発事故により放出された放射性微粒子中に含まれる難揮発性核種
の分析
五十嵐淳哉* ¹、鄭建’、張子見’、二宮和彦’、佐藤志彦’、福田美保’、悅有意’’、青野辰雄’、篠原厚¹大阪大学大学院理学研究科²量子科学技術研究開発機構放射線医学総合研究所福島再生支援本部³日本原子力研究開発機構廃炉国際共同センター ‘北京大学物理学院*責任著者: igarashij17@chem.sci.osaka-u.ac.jp福島原発事故では放射性Csを高濃度に含む放射性微粒子が放出された。この粒子は不溶性であることから放出時の物理化学状態を保持していると考えられ、粒子の組成分析により事故時の炉内環境についての情報を得ることが期待される。本研究ではCsよりも揮発性が低く、炉内の酸化還元雰囲気の違いに応じて揮発性が変化するSr,Puを放射性微粒子から定量することで、放射性微粒子の生成過程の解明を試みた。本研究ではCsの放射能比から1号機由来と2,3号機由来であると推測された放射性敵粒子について、放射化学分析とICP-MS賀量分析を行うことで、Sr(90Sr)とPu(239Pu,240Pu)を定量した。定量の結果、粒子中における90Sr/137Csについては全ての粒子で値が10-4程度であった。一方239+240Pu/137Csについては、1号機由来の粒子では10-8程度の値であったが、2,3号機由来の粒子では検出限界値未満（10-8未満）であったため、1号機と2,3号機では温度や酸化還元雰囲気などの粒子の生成環境が異なることが推測された。キーワード：放射性微粒子、放射化学分析、ICP-MS、ストロンチウム、ブルトニウム
P-120
Analyses for physicochemical properties in radioactive particles by a
synchrotron x-ray: Part 2
Yukihiko Satou* ¹ , Keisuke Sueki ² 1 Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency ² Centre for Research in Environmental Dynamics, University of Tsukuba *Corresponding author: satou.yukihiko@jaea.go.jp New types of radioactive particle which is main component is silicon (Si) discovered in the environment at the Fukushima Dai-ichi Nuclear Power Station accident. Large amount of similar particles are expecting remain in reactor buildings needs prevent from exhausted to the environment at accident during decommissioning works. The particles contain valuable information not only its physicochemical properties but also the particles generated environment. Electron state of each element shows particle generated surrounding environment. This work focus on particle from Unit 1, which was released at hydrogen explosion in 12th March 2011 and obtained electron state of containing elements in the surface layer of the particles by a Hard x-ray photoelectron spectroscopy(HAXPES) in BL22XU, which is exclusive beamline for JAEA, at SPring 8. Iron(II) oxide, CsSiFeO4 and metric iron(0) detected from all analysed particles. This result suggest iron capture process has occurred in a reduction environment or low concentration of oxygen. Presence of metallic caesium, which was observed in last year, could not detected in this experiment. Detection of the metallic cesium in experiments in last year predicted that the particle generated location would be more close to the reactor core which is a reducing atmosphere. Present evidence suggest that the particles generated in operation floor in reactor building. Keywords : radioactive particle, synchrotron x-ray, HAXPES, reduction, oxidation
シンクロトロン放射光を利用した放射性微粒子の物理化学性状解明2
佐藤志彦* '、末木啓介²
'日本原子力研究開発機構廃炉国際共同研究センター ²筑波大学アイソトープ環境動態研究センター *責任著者：satou.yukihiko@jaea.go.jp福島第一原子力発電所事故では、過去の原子力災害で見られなかったケイ茶が主成分の新しい放射性微粒子が環境中で発見された。同様な放射性粒子は原子炉の中にまだ多くが残留していると推定され、廃炉作業中に放出するといった新たなリスクとなりうることから、粒子の生成箇所を特定し放出抑止策を定めることが火急の課題である。以前から放射性粒子を分析することで、粒子そのものの性状に加え粒子が生成した時の情報も得られることが知られており、生成環境やケイ素の供給源の特定から飛散防止策の検討を行っている。本研究課題では前年に続き、筑波大学から提供された福島第一原発１号機から放出した放射性微粒子を、大型放射光施設(SPring-8)のJAEA専用ビームライン(BL22XU)において、硬X線光電子分光(HAXPES)を行い、粒子表面付近に存在する元素の電子状態を観察することで、粒子生成時の周辺環境推定を試みた。本年度の実験で対象とした粒子のすべてから酸化鉄(II)(FeO)とCsSiFeO4の存在が示された。また酸化数0の金属鉄も確認された。一般的に鉄は参加されると酸化鉄(III)(Fe2O3)で安定することから、鉄が粒子に取り込まれる過程は極めて酸素が少ないあるいは還元的な雰囲気の中で生じたと推定された。一方、前年の実験で示唆された酸化数0の金属セシウムの存在は裏付けるに至らなかった。キーワード：放射性微粒子、放射光、硬X線光電子分光、還元、酸化
P-121
Development of chemical separation method of Np for the determination of Np-237 in environmental by accelerator mass spectrometry Y. Hayakawa ¹ , N. Matsumura ² , A. Sakaguchi ³ , A. Nakajima ¹ , K. Teranishi ¹ , R. Morita ¹ , A. Yokoyama* ⁵ ¹ Graduate School of Natural Science and Technology, Kanazawa University ² College of Science and Engineering, Kanazawa University ³ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba 4 Mathematics and Science, University of Tsukuba 5 Institute of Science and Engineering, Kanazawa University *Corresponding author: yokoyama@se.kanazawa-u.ac.jp Development of a chemical separation method for the determination of 237Np, an isotope of minor-actinide Np, which is slightly present in the environment due to the release from nuclear facilities, is useful in various earth science fields such as surface material circulation, environmental pollution assessment and so on. The measurement of 237Np could be quantified by accelerator mass spectrometry, although an internal standard method for Np needs an appropriate spike. A candidate of the spike,236gNp, can be produced in some nuclear reactions with U or Th target material. However, the Np component should be isolated from a high matrix sample with the target material. In this experiment, techniques of nuclear chemistry were applied to purification of Np in the solutions of the irradiated samples by using a simple chromatography with TEVA and UTEVA resins in nitric acid and hydrochloric acid systems. As a result, obtained thus far, more than half of Np was recovered from high matrix samples. In addition, ICP-MS measurements indicate that more than 99.9% of interfering elements such as U and Th can be removed in the processes. From now on we will seek for a method with higher recovery of Np and utilize it for the application to accelerator mass spectrometry. Keywords : minor actinide, nuclear chemistry, chromatography, accelerator mass spectrometry
環境中ネプツニウム同位体測定法開発に関わる化学分離法の検討
早川優太'、松村夏紀'、坂口綾'、中島朗久'、寺西翔'、森田涼雅'、横山明彦* 5 ¹金沢大学自然科学研究科²金沢大学理工学域³筑波大学環境動態センター ‘筑波大学理工学群²金沢大学理工研究域*責任著者: yokoyama@se.kanazawa-u.ac.jp核関連施設を起源として環境中にわずかに存在するマイナーアクチノイドの同位体、237Npの定量法の確立により、表層の物質循環、環境汚染評価などの様々な地球科学分野への応用が期待される。237Npは加速器質量分析による定量が期待されているが、定量分析のための内標準となるスバイクが必要である。スバイクの候補として有望視されている236gNp核種は、核反応により製造でき、利用するためには照射ターゲット試料から分離する。この試料中には核分裂生成物が同時に製造されており、ターゲット物質を主体とする高マトリクス試料からのNpの精製が必要となる。本研究では核化学的手法によって得られたNp同位体を含む照射試料を溶解して硝酸系・塩酸系に調整し、固相抽出樹脂であるTEVA樹脂, UTEVA樹脂を用いた簡便なNpの分離法について検討を行った。今まで得られた結果では、高マトリックス試料からでもNpを半分以上回収することに成功している。また分離試料についてICP-MSによる測定を行い、U, Thなどの妨害となる元茶（ターゲット物質）が99.9%以上除去できることを確かめた。今後はよりNpが損失しない収率の高い手法を目指して検討を続け、加速器質量分析への適用を目指す。キーワード：マイナーアクチノイド、核化学、因相抽出樹脂、加速器質量分析
P-122
Removal of metal ion pollutants from waste water by using porous
amorphous Fe2O3
Bashir Ahmmad Arima* ¹ , M. Ferdous Alam ² , Zinnat A. Begum ³ , Ismail M.M. Rahman ¹ 1 Gaduate School of Sceience and Engineering, Yamagata University, Japan ² Graduate School of Symbiotic System Science and Technology, Fukushima University, Japan 3 Venture Business Laboratory, Advanced Science and Social Co-Creation Promotion Organization, Kanazawa University, Japan 4 Instiute of Environmental Radioactivity, Fukushima University, Japan *Corresponding author: arima@yz.yamagata-u.ac.jp Mesoporous Fe2O3 was synthesized by a simple chemical route and later characterized by a set of complementary techniques such as XRD, XPS, SQUID and BET surface analysis. XRD and SQUID analysises show that the material is amorphous and superparamagnetic ferromagnetic, respectively. The BET surface area of the materials was measured to be 229 m2/g. The adsorption of cesium on the mesoporous Fe2O3 was studied in a batch process using aqueous solutions of CsCl at varying concentrations. The other variables include solution pH, initial element content, adsorbent volume, and sorption duration. The adsorption isotherm was analyzed using the Langmuir and Freundlich equations models. Kinetic and equilibrium aspects of the adsorption process were also studied. Keywords : iron oxide, adsorption, cesium
多孔性アモルファスFe2O3による汚染水の吸着・分離に関する研究
有馬ボシールアハンマド* ′、エムフェルドースアラム²、ジンナットアラベガム³、イスマイルエムエムラハマン4
 
²福島大学大学院共生システム理工学研究科³金沢大学先端材料・社会共創推薦機構ベンチャービジネス・ラボラトリー '福島大学環境放射能研究所*責任著者：arima@yz.yamagata-u.ac.jp簡単な化学反応法で多孔性の酸化鉄（Fe2O3）を合成し、X-線回析、X線光電子分光法、SQUID, BET比表面積測定など用いて試料の分析測定を行った。その結果、合成した試料はアモルファスで超常磁性体である事が分かった。また、BET比表面積測定から比表面積は229m²/gである事が分かった。合成した試料を用いて汚染水からCsの吸着・分離束験を行った。吸着量への汚染水のpH,濃度、吸着時間などの影響について調べた。吸着等温線はラングミュア及びフロイントリッヒのモデルを用いて考察した。また、セシウムの吸着に関するキネティック、化学平衡について考察した。キーワード：金属酸化物、吸着、セシウム
P-123
Remediation of radiocesium contaminated soil
Zinnat Ara Begum* ¹.² , Ismail M.M. Rahman ³ , Hiroshi Hasegawa 4 1 Venture Business Laboratory, Advanced Science and Social Co-Creation Promotion Organization, Kanazawa University, Japan ²  Department of Civil Engineering, Southern University Bangladesh ³ Institute of Environmental Radioactivity, Fukushima University, Japan 4 Institute of Science and Engineering, Kanazawa University, Japan *Corresponding author: zinnat.ara@staff.kanazawa-u.ac.jp Decontamination of soil containing radioactive materials, especially radiocesium, is a critical issue because of its long half-life (30 years for 137Cs). The removal of contaminated soil without pretreatment would create a vast quantity of radioactive waste. Therefore, the separation of radiocesium from the soil is needed to minimize the quantity of radioactive waste. Removal of radiocesium can be done by sublimation using heat treatment, separation of soil by grain size in water, and treatment with chemicals, such as oxalic acid, aqueous potassium solution. The current study is focused on measuring the removal rate of radiocesium from contaminated soils with the aqueous solution of ammonium and potassium because radiocesium can be displaced with monovalent cations NH4+ and K+ via the ion-exchange mechanism. The chelator-assisted washing aided by the solution of NH4+ and K+ were also studied for the extraction of radiocesium from Fukushima-derived contaminated soils. The soil samples were crushed with a mortar, pass through 2 mm size sieve, and dried at 105 °C . The samples were then treated with chelators and different concentrations of ammonium and potassium-containing aqueous solution at changed soil to extractant ratio. The efficiency of the different extractant shows that 1.0 M ammonium solution (soil to extractant ratio, 1:10), 0.5 M ammonium solution (soil to extractant ratio, 1:20), and 1.0 M potassium solution (soil to extractant ratio, 1:10) can reduce nearly 15% of radiocesium from contaminated soil. The individual chelators have no significant influence on the 137Cs extraction rates. The combined extraction efficiency of chelators and ammonium or potassium solution is more or less equal to individual ammonium or potassium solution, which could be due to the unstable complexation ability of chelators with monovalent cations. Keywords: decontamination, extractant, chelators, radiocesium.
P-124
Analysis of effects of radioactive particles on crop cultivation
Naoto Nihei* ¹ , Kazuya Yoshimura ²
¹ Graduate School of Agricultural and Life Sciences, The University of Tokyo ²  Sector of Fukushima Research and Development, Japan Atomic Energy Agency *Corresponding Author：anaoto@mail.ecc.u-tokyo.ac.jp To safely cultivate agricultural products in radiocesium-deposited areas, decontamination works have been carried out for agricultural fields. However, they have not been completed in the areas. Some of the deposited radiocesium have been in the ground surface and are continuously released into the atmosphere. Therefore, it is important to assess the radioactive deposition on plants. The purpose of this study was to assess the radiocesium deposition on crops caused by the resuspended matter. Komatsuna ( Brassica rapa L. var. perviridis ) as tested crop was cultivated in pots, and the pots were arranged 30 and 120 cm above the ground surface. Pots were set in the site of Okuma Town and Tomioka Town. In addition, water in a container was set beside the pot to evaluate the amount of radiocesium in atmospheric fallout. The radiocesium concentration of Komatsuna, 4–57 Bq/kg (dry weight), and fallout, 15-370 Bq / m², fluctuated seasonally at the same place. It suggests that the factors involved in the change were meteorological. The radiocesium concentration of Komatsuna washed with water after harvest was predominantly lower than in the un-washed plants. Furthermore, Komatsuna cultivated at 30 cm above the ground tended to have a higher radiocesium concentration than cultivated at 120 cm. Therefore, it can be posited that radiocesium detected in Komatsuna was present because of the adhesion of floating matter from the ground surface. Keywords : radiocesium, resuspended matter, crop
放射性微粒子の作物栽培への影響解析
二瓶直登* ¹、吉村和也²
'東京大学大学院農学生命科学研究科
²日本原子力研究開発機構福島研究開発部門福島環境安全センター *責任者：anaoto@mail.ecc.u-tokyo.ac.jp放射性セシウム（Cs）が沈着した地域で安全に農業生産するために、除染作業が行われている。しかし、全ての地域で除染が実施されていないため、地面に降下した放射性Csが雑誌的に再浮遊している。そのため、再浮遊した放射性セシウムの作物への影響を評価することは重要であるが、これまでにほとんど報告がない。本課題の目的は、再浮遊した放射性Csが作物にどの程度沈着するか、またその要因を検討した。供試作物としてコマツナを用い、大熊町、富岡町でコマツナを地際から30cm、120cmに設置したポットで栽培した。併せて大気降下物中の放射性Cs量を評価するためポット脇に容器に入れた水も設置した。コマツナ地上部の放射性Cs濃度は4–57 Bq/kg (乾物重)、降下物は15-370 Bq / m²であった。コマツナ、水盤の値は同場所においても季節により変動し、変動要因については気象が関与していることが示唆された。収穫後水洗浄したコマツナの放射性Cs濃度は洗浄前に比べて低下した。更に、地際30cmで栽培したコマツナの放射性Cs濃度は120cmで栽培したコマツナに比べて高く、コマツナで検出された放射性Csは地表面からの浮遊物の付着であると想定される。キーワード：放射性Cs、浮遊物、作物
P-137
Facilities development for analysis of radionuclides in environmental samples collected from Ruppur Nuclear Power Plant (RNPP), Bangladesh M. Safiur Rahman ¹ *, M.M.A Mollah ² , S.M.A. Salam ² , M.A.B. Siddique ³ , M.R. Zaman ² , G. Yang ⁴ , H. Tazoe ⁴ ¹ Atmospheric and Environmental Chemistry Lab., Chemistry Division, Atomic Energy Centre, Bangladesh ² Laboratory for Environmental and Tracer Studies, Faculty of Engineering, University of Rajshahi ³ Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, Bangladesh. 4  Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, Japan * Corresponding author: safiur.rahman@dal.ca Ruppur nuclear power plant (RNPP) is under construction in the study area (Ruppur, Pabna District, Bangladesh), which has schedule for power production in 2023. Most of the local people generally consume groundwater from hand- tube wells, and groundwater also is used for cultivation in the areas of RNPP. Therefore, this study has been designed to collect ground water samples from twelve different sampling points surrounding RNPP site for determining the present status of heavy metals concentration in groundwater and to assess human health risk related to heavy metals contamination in groundwater. The concentrations of Pb, Cd, Cr, Fe, Mn, As, Ni, Cu, and Zn in the groundwater samples were determined using Atomic Absorption Spectrometer (GTA 120-AA240Z, Varian, Australia) at Bangladesh Council of Scientific and Industrial Research (BCSIR). This study revealed that the concentrations of heavy metals in groundwater samples for this study area in decreasing order was as follows: manganese > iron > lead > chromium > cadmium respectively. As, Ni, Cu, and Zn concentrations in the water samples were found to be below detection level. The level of target hazard quotient (THQ) in ingestion in the study area followed the order: Mn > Cr > Pb > Cd > Fe respectively. Subsequently, this study revealed that THQ values for Mn were lower than 1 in five sampling points except 1 sampling point, which indicating that there is no adverse health effects on human body in the study area for the selected metals. THQ values of dermal for all the heavy metals were less than 1. However, hazard index (HI) values for dermal adsorption of Pb, Cd, Cr, Fe and Mn are smaller than 1 indicating that there is no adverse health effects on human body and potential non carcinogenic concern via dermal adsorption of water. Keywords : Ruppur Nuclear Power Plant, heavy metals, target hazard quotient, hazard index
P-125
Studies on the effective dose for public calculated by air dose rate
Yuya Endo* ¹ , Katsuhiko Yamaguchi ³ , Tsugiko Takase ³ , Yasuhiro Uezu ² , Hirofumi Tsukada 4
' Graduate School of Symbiotic Systems Science and Technology, Fukushima University ² Japan Atomic Energy Agency ³ Faculty of Symbiotic Systems Science, Fukushima University 4 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: s1972002@ipc.fukushima-u.ac.jp After the Fukushima Dai-ichi Nuclear Power Station accident, the Ministry of the Environment decided that the additional annual dose in a high exposure situation (less than 20mSv/y) reduced to 1 mSv/y or less. The additional annual dose is calculated by ambient dose equivalent. However, the relationship among air kerma, ambient dose equivalent and effective dose seems to be identically by many people. In addition, conversion coefficients from air kerma and ambient dose equivalent to effective dose have been considered to change as time proceeds because the half-lives of 137Cs and 134Cs are different. Therefore, agricultural land in an evacuation zone was selected to evaluate relationship among them. Furthermore, the actual environment such as soil will be simulated by using a monte carlo radiation transport code PHITS. Finally, the relationship will be verified by comparing the results calculated by PHITS to ones obtained from actual environmental monitoring. Keywords : additional annual dose, effective dose, external dose, monte carlo radiation transport code PHITS
空間線量率を用いた実効線量推定手法の高精度化
遠藤佑哉* ¹²、山口克彦³、高瀬つぎ子³、植頭康裕、塚田祥文ʻ ¹福島大学大学院共生システム理工学研究科²国立研究開発法人日本原子力研究開発機構³福島大学理工学群共生システム理工学類'福島大学環境放射能研究所*責任著者: s1972002@ipc.fukushima-u.ac.jp 2011年の東京電力ホールディングス株式会社福島第一原子力発電所事故を受け、環境省は、年間追加被ばく線量が20 mSv年·¹未満である地域については、長期的な目標として追加被ばく線量が年間1mSv以下になることを目指すとの基本方針を示した。しかし、現在はこの年間追加被ばく線量の計算において、空気カーマ、周辺線量当量及び実効線量が同一なものとして扱われていることが多い。また、環境中に放出された137Cs及び134Csは、その物理学的半減期が異なることから、空気カーマ及び周辺線量当量から実効線量への換算係数が時間経過とともに変化する。そこで、経時変化に対応したこれらの関係性から換算係数を求めるため、比較的一様に放射性セシウムが沈着したと考えられる帰還困難区域内にある農地を選定した。実環境での土壌中放射性セシウムからの放射線をモンテカルロ放射線輸送計算コードPHITSを用いて模擬し、本シミュレーションにより得られた計算結果と実測値を比較することで、空気カーマ、周辺線量当量及び実効線量の関係性について検証する。キーワード：追加被ばく線量、実効線量、外部被ばく、モンテカルロ放射線輸送計算コードPHITS
P-126
The temporal variations of radio-cesium concentration in air in Okuma
Shigekazu Hirao* 1
1 Institute of Environmental Radioactivity, Fukushima University *Corresponding author: s-hirao@ipc.fukushima-u.ac.jp The radionuclides that were released by the accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March, 2011 were deposited on land surfaces in Tohoku and North Kanto regions by dry and wet deposition. Decommissioning of the FDNPP and decontamination in the evacuation zones are being conducted. Eventually, the evacuation zones will be lifted. Therefore, monitoring radioactivity concentrations in the air and the analysis of their spatial and temporal variation are required. To obtain radioactivity concentrations in the air, airborne particles were collected on filters by using high-volume air samplers. The Cs-134 and Cs-137 radioactivities of the filters were measured with HPGe semiconductor detector to derive the activity per unit volume of air. Polytetrafluoroethylene filters were used. The sampling intervals were between two weeks and one month. The sampling site was located on Okuma. The air monitoring were conducted during November, 2013 to the present. The measured Cs-137 radioactivity concentration in air for Okuma varied from 0.08 to 0.66 mBq m-3. The measured activity concentrations were still about two orders of magnitude higher than that obtained before the accident. The activity ratio of Cs-134/Ca-137 varied with time only by the radioactive decay. The atmospheric concentrations of Cs-137 seems to decrease with time. However, the recent temporal change in the atmospheric concentration of Cs- 137 from 2018 to the present shows no substantial decrease of concentration. The radioactivity concentrations in air increased with wind speeds, averaged over the sampling periods, except for the concentrations in summer when the mean wind speed was lower than for the other seasons. This implies that the increase in air radioactivity concentrations is not due only to wind-blown (eolian) dust but also from other processes. From the points of view of size  of airborne particles, the temporal change in activity concentration of Cs-137 depends strongly on the that of coarse particles that is larger than 1.1    μ  m. It is possible that decontamination activity near the sampling site enhance the atmospheric concentration of Cs-137. Keywords : Cs-137, Cs-134, atmospheric radioactivity concentration, resuspension
大熊町の大気中放射性セシウムの時間変化の測定
平尾茂一* 1
¹福島大学環境放射能研究所*責任著者: s-hirao@ipc.fukushima-u.ac.jp 2011年3月の福島第一原子力発電所事故により大気中に放出された放射性物質は、乾性・還性沈着によって東北および北関東の地表面に沈着した。今後、廃炉・除染作業が進むと同時に帰還困難区域が順次解除される見込みである。そのため大気中の放射能濃度をモニタリングし、その変動とその要因を明らかにすることが必要である。大気中濃度を得るためにハイボリュームサンプラーを用いて大気中の浮遊塵をフィルター上に捕集した。フィルターのCs-134、Cs-137の放射能をHPGe半導体検出器で定量し、単位体積大気中の放射能を導出した。測定地点は双葉郡大熊町（大熊）とした。サンプリングの時間間隔は、2週間から一ヶ月間である。測定期間は、2013年11月から現在までである。大気中Cs-137濃度は、0.08-0.66 mBq m 3であった。現在の大気中濃度は、事故前の福島での濃度と比べて2桁程度高い。Cs-134とCs-137の濃度比は、放射壊変のみの時間変化を示した。大気中濃度は減少傾向を示しているが、 2018-2019年にかけて減少傾向は見られなくなってきていることが分かった。また、ばらつきは大きいものの、大気中濃度は風速が強くなるほど高い傾向が見られた。この傾向は、地表面に沈着した放射性物質の風による再浮遊を示唆している。大気中微粒子の粒子径に着目すると、1.1 μ mより大きい大気中微粒子に放射能の大部分が保持されていることが示された。1.1 μ mより小さい大気中微粒子中の放射能は引き続き減少傾向を示している。大気中濃度の変動は、粒径の大きい大気中微粒子の変動に支配されており、除染作業による人為的な舞い上がりによる影響があると見られる。キーワード：Cs-137、Cs-134、大気中放射能濃度、再浮遊
P-127
Measurement of emission flux of radioactive cesium to the atmosphere
Olivier Masson ¹ , Kita Kazuyuki* ² , Denis Maro ¹ , Harada Koshi ² , Hayashi Naho ² , Minami Kohtaro ² , Hatano Yuko ³ , Igarashi Yasuhito ¹ ,4 ¹ Environmental Radioactivity Study and Monitoring Department, IRSN ² Graduate school of Science and Engineering, Ibaraki University 3 Center for Research in Isotopes and Environmental Dynamics, Tsukuba University 4 Institute for Integrated Radiation and Nuclear Science, Kyoto University *Corresponding author: kazuyuki.kita.iu@vc.ibaraki.ac.jp Radio-cesium emitted by the TEPCO FDNPP accident has been deposited on soil and vegetation after transpiration in the atmosphere. Re-suspension of the deposited radio cesium is increased atmospheric concentration of its radioactivity even now. Quantitative understanding of re-suspension flux of radio-cesium is essential for the modelling of radio- cesium transition from soil and vegetation via the atmosphere. For this purpose, we have developed 1-bix and 2-box models to evaluate the emission of radio-cesium by the re- suspension from surface. In these models, the temporal variation of atmospheric concentration of radio-cesium radioactivity is considered to be balance be the difference of emission and deposition in the 1-box model, and by the difference of emission, deposition and vertical diffusion in the 2-box model. Using the atmospheric concentration data of radio-cesium radioactivity derived from continuous air sample of 12-hour interval at Namie site, Fukushima, in some weeks between March and September, 2019. Dry and wet deposition flux are evaluated from the data of passive sampling of deposited aerosols and rain water at the same site and during same periods. Meteorological parameters were also measured with automated weather station at the site. Vertical diffusion of radio-cesium activity concentration was estimated from two heights (0.6 and 5m) air sampling using 6.5m tower as well as measurement of sensible heat flux measurement by ultrasonic anemometer and two heights temperature measurement. Using these box models, the resuspension flux coefficient was evaluated and its values were positively correlated with the surface wind speed, indicating that the re-suspension is activated by wind blow at the surface especially in spring (March and May). Keywords : atmospheric radio-cesium, re-suspension, emission flux, box model
P-128
Evaluation of dose from handling radionuclides contaminated
materials
Kazuji Miwa* ¹ , Takeshi Iimoto ² , Shigekazu Hirao ³ ¹ Department of Environment Systems, Graduate School of Frontier Sciences, University of Tokyo ² Graduate School of Frontier Sciences, University of Tokyo ³ Fukushima University *Corresponding author: miwa.kazuji@jaea.go.jp As the first year of this research, we focus on dose evaluation by reusing radionuclides contaminated materials which are generated by radiation emergency. We evaluate exposure dose by radiocesium which is discharged into the ocean by assuming using radiocesium-contaminated soil to coastal reclamation. Mitta, et al, 20191 evaluated internal exposure dose by marine products ingestion. By this study, it is suggested the external exposure dose of public on beach is same order as the internal exposure dose by marine products ingestion which is the highest exposure dose from radiocesium in ocean. We also evaluate external exposure dose assuming use of contaminated rubble for material of parking place in Fukushima Daiichi NPS (1F). Miwa, et al., 2019 ² evaluated exposure dose by use of contaminated rubble for road material. The length of parking place is shorter than the road, however dose conversion coefficient by radiocesium for worker on the parking place is almost same with the value of worker on the road in previous study. Keywords : radiocesium-contaminated soil, contaminated ruble, reusing, exposure dose evaluation
放射性物質で汚染された物品等の扱いによる影響の評価
三輪一雨* ¹、飯本武志²、平尾茂一²
'東京大学大学院新領域創成科学研究科環境システム学専攻²東京大学院新領域創成科学研究科²福島大学*責任著者：miwa.kazuji@jaea.go.jp研究初年度となる令和１年度は、放射線災害にて発生した放射性物質で汚染された物品等の扱いとして、資源の有効活用の観点から再生利用に着目した。本研究では、除去土壌を海面埋立地に再生利用することを想定したときの、海洋へ流出した核種による被ばく線量を評価した。既往評価として、海産物摂取による内部被ばく線量を評価したMiwa, et al., 2019'がある。ここでは海岸活動者の外部被ばくについて着目し、海洋へ流出した核種からの被ばく線量が最も大きい海産物摂取（成人）と同オーダーであることが分かった。また、福島第一原子力発電所(1F)敷地内にある汚染がれきを敷地内の駐車場の補修に再生利用すること想定した際の被ばく評価を行った。既往研究には道路への再生利用に関するMinoa, et al, 2019がある。放射性セシウムからの外部被ばくを考慮した場合、補修箇所中央高さlmの外部被ばく線量換算係数は、評価体系の長さが大きく異なるが、結果としては道路に関する評価値と同程度になった。 1 Mitva, et al., Radiation Protection Dosimetry, 184, 2019, 2 Mitva, et al., Progress in Nuclear Science and Technology, 6, 2019キーワード：除去土壌、汚染がれき、再生利用、線量評価
P-129
Modeling of time series data of radioactive cesium concentration in lake
water of Lake Onuma on Mt. Akagi
Yukiko Okada* ¹ , Eiichi Suetomi ¹² , Takafumi Uchiyama ¹ , Masakiyo Fujita ³ , Yuko Hatano ³
¹ Atomic Energy Research Laboratory Tokyo City University ²  Faculty of Engineering, Information and Systems University of Tsukuba 3  Graduate School of Systems and Information Engineering University of Tsukuba *Corresponding author: yokada@tcu.ac.jp The Fukushima Dai-ichi Nuclear Power Plant accident released large amounts of radioactive cesium into the environment. Concentration of radioactive Cs-137 (RCs) exceeding the regulated value was also detected in fish such as wakasagi (Hypomesus nipponensis), a representative lake products in Lake Onuma on Mt. Akagi, Gunma Prefecture. After that, the RCs concentration of the lake water rapidly decreased, but its pollution was protracted. The purpose of this study is to develop a model that can reproduce the peculiar time-dependent RCs variation in the lake water of Lake Onuma on Mt. Akagi, and to predict the pollution level of the lake in the future. An analytical solution is obtained, assuming that vertical diffusion in the lake water is represented by a fractional diffusion equation with respect to time. The Mittag-Leffler function is known as a fundamental solution of such an equation. In this study, the Mittag-Leffler function is expanded to a series of up to 100. When this equation was fitted to the time-series data of the measured values, they agreed well. This gives the prospect of long-term prediction of the decay of RCs concentration. Keywords : radiocesium (137Cs), FDNPP accident, lake water, long-term prediction, fractional diffusion equation, Mittag-Leffler function
赤城大沼湖水中における放射性セシウム濃度の時系列データに関す
るモデル化
岡田往子* ¹、末富英一¹²、内山孝文¹、藤田真聖³、羽田野祐子³
'東京都市大学原子力研究所²筑波大学システム情報系³筑波大学大学院システム情報工学研究科*責任著者: yokada@tcu.ac.jp福島第一原子力発電所事故により放射性物質が環境中に放出された。群馬県赤城大沼の代表的水産物のワカサギをはじめとする魚類からも暫定規制値を超える放射性Cs-137(RCs)が検出された。その後、湖水のRCs濃度は急速に低下したがその汚染が遷延し、新基準値未満ではあるものの湖水中RCsと強い相関を持つワカサギもRCsレベルがほぼ一定となり、全国の湖沼の中でも特異的な挙動を示している。本研究の目的は赤城大沼の湖水中RCsに見られる特異な経時変化を再現できるようなモデルの開発を通して今後の赤城大沼の汚染レベルの子測に繋げることにある。湖水中の鉛直拡散が、時間に関する非整数階微分を含む拡散方程式で表されると仮定し、その解析解を求める。このような方程式の基本解としてMittag-Lefler関数が知られている。本研究ではMittag-Lefler関数を100項まで級数展開した。この式を測定値の時系列データにフィッティングしたところよく一致した。これによりRCs濃度の減衰の長期予測の見通しを得た。キーワード：放射性セシウム(137Cs)、福島第一原子力発電所事故、湖水、長期子測、非整数階拡散方程式、Mittag- Leffler関数
P-130
Development of mathematical model for long-term prediction of radioactive cesium concentration in airborne particulate matter Eiichi Suetomi* ¹² , Yukiko Okada* ¹ , Naoto Hagura ¹ , Takafumi Uchiyama ¹ , Yuko Hatano ³ 1 Atomic Energy Research Laboratory, Tokyo City University ² Faculty of Engineering, Information and Systems, University of Tsukuba ³ Graduate School of Systems and Information Engineering, University of Tsukuba *Corresponding author: esuetomi@tcu.ac.jp The Fukushima Dai-ichi Nuclear Power Plant accident released radioactive Cs-137 (RCs) into the environment and affected the Kanto region. The concentration of RCs in the atmosphere has been measured before the accident at Tokyo City University (TCU) Atomic Energy Research Laboratory in northern Kawasaki City, Kanagawa Prefecture, high concentrations of RCs were detected after the accident. After that, the concentration of RCs decreased rapidly, but after half a year the RCs decreased slowly. Several models have been proposed for the time dependent RCs concentration in the Chernobyl accident, and the same phenomenon has been successfully explained. However, these models need a large number of fitting parameters. In addition, there was a problem that the value diverged at time zero (at release time). In this study, we propose a long-term prediction model of RCs concentration by a new method to solve these problems. From the time dependent data analysis at the Chernobyl accident, transport phenomena of RCs in the atmosphere can be regarded as anomalous diffusion. The anomalous diffusion can be represented by the fractional diffusion equation (FDE). The analytical solution was obtained by separation of variables the FDE into time and space variables and averaging the space. The validity of the analytical solution was shown by comparing the analytical solution with the RCs concentration in airborne particulate matter measured by the Atomic Energy Research Laboratory at TCU. Keywords : radiocesium ( 137 Cs), FDNPP accident, atmosphere, long-term prediction, fractional diffusion equation
大気浮遊塵中の放射性Cs濃度の長期予測に関する数理モデルの開発
末宮英一* ¹²、岡田往子'、羽倉尚人'、内山孝文'、羽田野祐子'
¹東京都市大学原子力研究所²筑波大学システム情報系³筑波大学大学院システム情報工学研究科*責任著者: esuetomi@tcu.ac.jp福島原子力発電所事故では環境中に放射性Cs-137 (RCs)が放出され、その影響は関東地方にも及んだ。神奈川県川崎市の東京都市大学原子力研究所では事故以前から大気中のRCs濃度の計測を行ってきたが事故以前は検出限界下であったRCsが高濃度で検出された。その後RCs濃度は急激に減衰したが、半年後からRCsの減衰は緩慢になっている。チェルノプイリ事故のRCs濃度の経時変化についてはいくつかのモデルが提案され同様の現象の説明に成功している。しかしこれらのモデルはフィッティングバラメータ数が多い。加えて時刻客（放出時）で価が発散する等の課題があった。本研究ではこれらの課題を解決すべく新たな手法によりRCs濃度の長期子測モデルを提案する。チェルノプイリ事故時のデータ解析から大気中のRCsの輸送現象は異常拡散とみなせる。異常拡散は非整数階拡散方程式(FDE)となることが知られている。本研究ではFDEを時間と空間に変数分離し、空間について平均化することで時間依存の解を求めることでRCs濃度の迅速な長期的子測を可能にすることができた。得られた解析解と東京都市大学原子力研究所で計測された大気浮遊塵中RCs濃度とを比較し、解析解の妥当性を示すことが出来た。キーワード：放射性セシウム(137Cs)、福島第一原子力発電所事故、大気、長期予測、非整数階拡散方程式
P-131
Prediction of radiocesium behavior based on concentration profile
and mass transfer simulation Tetsuo Yasutaka* ¹ , Koki Matsushita ² ¹ National Institute of Advanced Industrial Science and Technology ² University of Tsukuba *Corresponding author: t.yasutaka@aist.go.jp The behavior of radiocesium in the soil is affected by soil physicochemical properties such as partition coefficient, organic matter content, soil nature. The partition coefficient of radioactive cesium in soil is generally determined by a batch adsorption test, but it has been pointed out that it is significantly different from the actual phenomenon. In this study, we estimated the partition coefficient and predicted the long-term behavior by inverse analysis by the one- dimensional transfer simulation software HYDRUS-1D using the vertical profile data of radioactive cesium in soil obtained at the University of Tsukuba. Keywords : radiocesium, partition coefficient, inverse analysis, mass transfer simulation濃度プロファイルと物質移動シミュレーションに基づく放射性セシウムの挙動予測保高徹生* '、松下恒輝* ¹産業技術総合研究所²筑波大学*責任著者: t.yasutaka@aist.go.jp土壌中の放射性セシウムの土壌中での挙動は、分配係数、有機物含有量、土質等の土壌の物理化学性等に影響を受ける。土壌中の放射性セシウムの分配係数は、バッチ吸着試験で求めることが一般的であるが、実現象とは大きく異なるとの指摘もある。本研究では、筑波大学でこれまで取得してきた土壌中の放射性セシウムの鉛直プロファイルデータを活用し、1次元の物質移動シミュレーションソフトであるHYDRUS-1Dを用いて、逆解析による分配係数の推定および長期的な挙動予測を実施した。キーワード：放射性セシウム、分配係数、逆解析、物質移動シミュレーション
P-132
Radiocesium resuspension caused by the decontamination and demolition work at a special reconstruction and revitalization base of the difficult-to-return zone in Tomioka Town, Fukushima Prefecture Yasuyuki Taira* ¹ , Masahiko Matsuo ¹ , Shigekazu Hirao ² ¹ Atomic Bomb Disease Institute, Nagasaki University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: y-taira@nagasaki-u.ac.jp Based on  “Specified Reconstruction and Revitalization Base Plan” for aiming at lifting evacuation orders and allowing the residents to return by the Act on Special Measures for the Reconstruction and Revitalization of Fukushima (May 2017), six municipalities near the Fukushima Daiichi Nuclear Power Station (FDNPS) have made efforts of  the decontamination work such like removing deposits from roofs, wiping off roofs and walls, high-pressure washing of houses and buildings, removing fallen leaves and stripping topsoil in garden and high-pressure washing of roads. Tomioka Town, Fukushima Prefecture is located 8.5 km south of the FDNPS. In Yonomori District (Tomioka Town), the decreasing time trends of the environmental radiation and confidence levels of radiocesium were consistent with the decreasing time trends of the ambient dose rates by the decontamination work. On the other hand, the radiation exposure level and resuspension by the decontamination work on the difficult-to-return zone have not been evaluated concretely. Therefore, the dust samples near the building where the decontamination work (including the demolition) is planned were collected using a high-volume air sampler (HV-1000R, Shibata Science Technology LTD, Saitama, Japan) during August to December, 2019, and analyzed using a high purity germanium detector (ORTEC® GMX series, Ortec International Inc., Oak Ridge, TN, USA) coupled to a multi-channel analyzer (MCA7600, Seiko EG&G Co., Ltd., Chiba, Japan) for 80,000 s. In the present study, 137Cs, which is considered to be derived from the FDNPS accident, were detected in some samples. These levels were 0.11 mBq/m3 after the decontamination work next to the target building is completed and 0.14 mBq/m 3 under the decontamination work next to the target building mBq/m 3 , respectively. On the other hand, 137Cs was also detected in a sample collected at Tomioka Town Office (0.034 mBq/ m³). These data were consistent with the survey results by Fukushima Prefecture Office. Since the decontamination work of the target building is not still started, however, further investigation with detailed conditions is needed while confirming the change of radiation doses by the decontamination work. Keywords : radiocesium, resuspension, decontamination, demolition （帰還困難区域）における除染・解体作業によ
る放射性セシウムの再浮遊・飛散性の動態把握
平良文字* ¹、松尾政彦¹、平尾茂一年¹長崎大学原爆後障害医療研究所¹福島大学環境放射能研究所*責任著者: y-taira@nagasaki-u.ac.jp福島県富岡町では、2023年春頃までに帰還困難区域全域の避難指示解除を目指しており、現在「特定復興再生拠点区域」である夜の森地区を中心に先行除染しているが、除去・解体作業に伴い、福島第一原子力発電所事故由来と考えられる放射性セシウムが含まれる大気浮遊艦の再浮遊による影響が懸念されている。そこで、当該地区で除染・解体作業が予定されている建屋敷地内で大気浮遊塵を捕集し核種分析した結果、137Csは＜ 0.14mBq/m³の範囲であった（2019年9 ～ 12月）。一方、対照地区である宮岡町役場では、0.034mBq/m³（2019年8月）であった。今回の結果は、福島県が実施している大気浮遊じん環境放射能測定結果（137Cs：0.088 ～ 0.39 mBq/m³、夜の森地区、2019年4 ～ 10月）の範囲内であったが、対象建屋の隣接エリアが除染中であった時の137Cs濃度（0.14mBq/m³）は、除染完了後の137Cs濃度（0.11mBq/m³）に比べやや高値を示したことから、除染・解体作業に伴う137Csの再浮遊が示唆されるものの、対象建屋の解体作業がいまだ未着手であるため、今後の詳細な調査及び解析が期待される。キーワード：放射性セシウム、再浮遊、除染、解体
Symposium
シンポジウム
S-1
Research on environmental radioactivity by the collaboration
between Fukushima and Chernobyl researchers
Nanba Kenji* 12 , Member of a Project of SATREPS program "Strengthening of the Environmental Radiation Control and Legislative Basis for the Environmental Remediation of Radioactively Contaminated Sites" 12345 ¹ Institute of Environmental Radioactivity, Fukushima University ² Faculty of Symbiotic Systems Science and Technology, Fukushima University ³ Graduate School of Symbiotic Systems Science and Technology, Fukushima University 4 University of Tsukuba 5 Fukushima Medical University *Corresponding author: nanba@sss.fukushima-u.ac.jp As nuclear power plants now exist every part of the world and a nuclear power accident rarely take place, the experiences and lessons thereby must be shared internationally.  After the accident in Fukushima those from Chernobyl nuclear accident have been utilized for the countermeasures and research activities. Ukrainian government has a plan to facilitate the utilization of Chernobyl Exclusion Zone (ChEZ) as a new industry area of nuclear management and solar power generation near NPP and a natural reserve area surrounding the industrial area.  The plan requires an investigation on radiation level and researches on the behavior of radionuclides in ChEZ. New methods of observations and analyses that have been developed after Fukushima Daiichi NPP accident were introduced and collaboration among Ukrainian and Japanese researchers have been implemented since the start of a five year project "Strengthening of the Environmental Radiation Control and Legislative Basis for the Environmental Remediation of Radioactively Contaminated Sites" in 2017 funded by SATREPS program.  The project includes 1. Researches on the behavior of radionuclides after the draw down of water in the Cooling Pond, 2. Researches on the behavior of radionuclides in the forest, grassland and rivers in ChEZ and 3. Researches on the dispersion of radionuclides from ChEZ. The project also includes reporting the Ukrainian government with the results from those researches to help the decision-making and contribution to international communities through publication etc. based on the collaborations. Keywords : Chernobyl, Fukushima, Exclusion Zone,
チェルノブイリと福島との環境放射能分野の共同研究
難波謙二* ¹²、SATREPS課題「チェルノプイリ災害後の環境管理支援技術の確立」参加メンバー12345 ¹福島大学環境放射能研究所²福島大学共生システム理工学類、’福島大学大学院共生システム理工学研究科*筑波大学5福島県立医科大学*責任著者: nanba@sss.fukushima-u.ac.jp原発は世界各地にある一方、稀にではあるが重大事故が起きることから、事故の経験や教訓を国際社会で共有する必要がある。事故後の対策や研究において、1986年に発生したチェルノブイリ原発事故と事故後の経験が福島で活かされてきてきた。ウクライナ政府は、チェルノプイリ立入禁止区域の有効利用を進める方針であり、中心エリアでは、廃棄物管理や太陽光発電など新産業を活発化させ、外側は野生生物の保護区とする計画である。これには放射線量の把握や放射能の動態の子測等の課題を伴っている。 2017年から5年間の計画でSATREPS課題として採択された「チェルノプイリ災害後の環境管理支援技術の確立」では福島で事故後、環境放射能研究分野で用いられた新たな観測や分析手法を導入し、チェルノブイリで研究を行ってきたウクライナの研究機関と共同で、①クーリングポンドの水位低下に伴う放射能動態の把握、②森林と草地と河川の放射能動態、④大気を通じた放射能の拡散という研究対象に取組んできた。これらの研究成果に基づいて、ウクライナ政府の政策決定に資するとともに国際社会に両国から貢献することを目指している。キーワード：チェルノブイリ、福島、避難区域
S-2
Childhood thyroid cancer around Chernobyl Nuclear Power Plant:
The differences with Fukushima
Noboru Takamura* ¹,² ¹ Atomic Bomb Disease Institute, Nagasaki University ² Institute of Environmental Radioactivity, Fukushima University *Corresponding author: takamura@nagasaki-u.ac.jp After the accident at Chernobyl Nuclear Power Plant, childhood thyroid cancer increased due to the internal exposure of I-131. About five years after the accident, thyroid cancer has increased in children who were 0-5 years at the accident. Based on the lessons of Chernobyl accident, food control was implemented just after the Fukushima accident, to minimize the internal exposure to the thyroid glad in children. Due to this food control policy, it has been showed that the internal doses in children of Fukushima was relatively limited. Keywords : Chernobyl, thyroid cancer, radioiodine
チェルノブイリ周辺地域における小児甲状腺がんの特徴、
および福島との相違について
高村昇* 1,2
¹長崎大学原爆後障害医療研究所²福島大学環境放射能研究所*責任著者：takamura@nagasaki-u.ac.jp 1986年のチェルノブイリ原子力発電所事故によって、特にヨウ素131といった短半減期性のヨウ素がヒト甲状腺の内部被ばくを引き起こしたことが知られている。事故から５年後の1990年ごろより、事故当時特に事故当時0歳から５歳といった世代における甲状腺がんの増加がみられた。2011年の東京電力福島第一原子力発電所事故直後、日本では暫定基準値を設定し、それを上回る食品について出荷制限、摂取制限の対象となった。これはチェルノプイリ事故の教訓を踏まえ、特に事故初期の放射性ヨウ素による小児の甲状腺内部被ばくを低減化することを目的としたものであった。これによって福島県における放射性ョウ素による甲状腺の内部被ばくは、チェルノブイリ周辺地域に比較しても十分に低いことが示されている。キーワード：チェルノブイリ、甲状腺がん、放射性ヨウ茶
S-3
Fukushima and Chernobyl: Similarities and differences in behaviour

Alexei Konoplev* ¹ ¹ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: r701@ipc.fukushima-u.ac.jp The ease with which radionuclide moves through the environment and is taken up by plants and animals is determined by its chemical forms and site-specific environmental characteristics. The peculiarities in climate, geomorphology and 137Cs speciation in the fallout were demonstrated to lead to differences in migration rates of 137Cs in the environment and rates of its natural attenuation. It has been revealed that in the exclusion zone the Fukushima-derived 137Cs is strongly bound to soil and sediment particles, which reduces potential bioavailability of this radionuclide. Up to 30% of the deposited 137Cs on soil of the exclusion zone were found to be incorporated in hot glassy particles (  "Cs balls"  ) insoluble in water. These particles are decomposing in the environment essentially slower as compared with Chernobyl derived fuel particles. Wash-off from the slopes of contaminated catchments and river transport are key long-term pathways for radionuclide dispersal from contaminated areas after the Fukushima accident. The climate conditions for the Fukushima Prefecture of Japan are characterized by higher annual precipitation (1300-1800 mm/year) with maximum rainstorm events during typhoon season. Typhoons Etou in 2015 and Hagibis in 2019 demonstrated the substantial redistribution of 137Cs on river watersheds and floodplains and in some cases natural self-decontamination occurred. Steep slopes of Fukushima catchments are conducive to higher erosion and higher particulate r-Cs wash- off. Irrigation ponds in Okuma and Futaba towns demonstrated persistent behavior of 137Cs similar to the closed lakes in Chernobyl, its concentration is decreasing slowly and showing regular seasonal variations: the 137Cs concentrations tend to grow in the summer and decrease in the winter. Keywords : Fukushima, Chernobyl, radiocesium, fate, transport, self-purification.
福島とチェルノブイリ：土と水の中の放射性核種の動き、似ている
ことと違うこと
Alexei Konoplev* 1
¹福島大学環境放射能研究所
*Corresponding author : r701@ipc.fukushima-u.ac.jp放射性核種が環境内を移動し、植物や動物に吸収される容易さは、その化学形態と固有の環境特性によって決まります。気候や地形、そして降下したセシウム137の化学形態が異なっていると、環境中のセシウム137の移動速度と自然減衰の速度に違いが生じることが示されています。避難区域では、福島由来の137Csが土壌および堆積物粒子に強く結合しており、この放射性核種の潜在的な生物学的利用能が低下することが明らかになっています。避難区域の土壌に堆積した137Csの最大30%が、水に溶けない熱いガラス状粒子（[Csボール]）に取り込まれていることがおかりました。これらの粒子は、チェルノプイリ由来の燃料粒子と比較して、環境中で（本質的に）ゆっくりと分解します。福島事故後、汚染された流域内の斜面からの土砂流出と河川によるその輸送は長期的な放射性核種の拡散経路です。日本の福島県の気候条件は、台風シーズン中に最大の暴風雨イベントを伴うより高い年間降水量（1300 ～ 1800 mm /年）によって特徴付けられます。2015年の台風18号(Etau)と2019年の台風19号（Hagibis）は、流域とその氾濫原での137Csの大幅な再拡散を起こし、場合によっては自然の自浄作用をもたらしました。福島の集水域の急斜面は、侵食の増加と粒子状の放射性Csの流出を促進します。大熊町と双葉町の灌漑池は、チェルノプイリの近くの湖に似た137Csの挙動を示しました。それは、ゆっくりとした137Csの濃度減少と、夏に濃度が上昇し、冬に減少するという季節性でした。キーワード:福島、チェルノブイリ、放射性セシウム、挙動、輸送、自己浄化
S-4
Chernobyl and Fukushima forests: Impacts and dynamics of
radioactive contamination
Vasyl Yoschenko* ¹ , Kenji Nanba ¹ , Valery Kashparov ² , Dmytrii Holiaka ² , Yuichi Onda ³ , Azusa Goto ¹ ,
Hiroko Nagata ¹ , Kenji Watanabe ¹ Institute of Environmental Radioactivity, Fukushima University, ² National University of Life and Environmental Sciences of Ukraine,  ³ Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba *Corresponding author: r705@ipc.fuksuhima-u.ac.jp Forests cover the major parts of areas that were radioactive contaminated due to the Chernobyl and Fukushima accidents. In this paper we analyze consequences of the two accidents for the forest ecosystems in Chernobyl and Fukushima, and make an attempt to evaluate the perspectives of revitalization of commercial forestry in the contaminated territories. In Chernobyl, especially in the near zone of the accident, forest ecosystems are considered as the environmental repositories of radionuclides that prevent spreading of radioactivity to the populated areas. Decontamination of Chernobyl forests has never been planned, and the forest countermeasures to cut trees and bury them in trenches that have been performed are aimed on prevention/reduction of the radiation exposures of population rather than on revitalization of forestry. The possibilities of economic activity in forests and utilization of forestry products are regulated by law and the national standards based on the radionuclide deposition levels and their concentrations in wood etc. On the other hand, in absence of the decontamination measures, Chernobyl forests provide the possibilities of the detail study of the long-term radionuclide dynamics in the forest ecosystem compartments. In our presentation, we analyze the major dynamics trends and identify the processes involved in the radionuclide redistributions in the ecosystems. In Fukushima, the extensive efforts have been applied to prepare return of people to evacuation areas. This includes decontamination of the residential and agricultural lands, roads etc. However, decontamination in forests is performed or planned only within the limited areas and, similarly to the countermeasures in Chernobyl, is aimed on reduction of the population exposures. In our presentation, we present our data on the radiocesium levels in typical forests in Chernobyl exclusion zone and Fukushima evacuation areas and on their dynamics, identify the processes that may determine its future trends, and discuss the revitalization perspectives of forestry in Fukushima. Keywords : forest ecosystems, Fukushima, Chernobyl, radionuclide dynamics; revitalization of forestry.
チェルノブイリと福島の森林：放射性セシウムの循環移動
ヨシェンコ　ヴァシル* ¹、難波謙二¹、カシュバロフヴァレリー²、ホリアカドミトリー²、恩田裕一³、
後藤あずさ'、永田広子'、渡邉憲司'
¹福島大学環境放射能研究所、2ウクライナ国立生活環境科学大学、3筑波大学アイソトープ環境動態研究センター *責任著者: r705@ipc.fukushima-u.ac.jpチェルノプイリおよび福島の事故で汚染された面積の中で森林は大きな割合を占める。この発表では、両方の事故による森林への影響について述べ、汚染した地域の林業を活性化させる見通しについて検討を試みる。チェルノブイリの、特に事故を起こした炉に近いところでは、森林生態系の役割として、放射性物質が安定に貯留され、そのおかげで居住区域への拡散を防止しているものと捉えられている。チェルノプイリでは森林の除染は計画されたことが無い。実施された伐採と埋設という対策は、林業復興のためというより、人の被曝を防止あるいは低減するのが目的である。森林を利用する経済活動や林産物の利用に対しては、法律があり、産地の放射性物質の沈着量と木材中の濃度等を定めた国の基準によって規制されている。他方、除染を行わないチェルノプイリの森は、森林生態系内の各構成部分で放射性核種が長期的にどのような動態を示すのか詳細に調べる機会を提供している。この発表では、生態系内の放射性核種分布について主な変化傾向とそのプロセスの分析結果を示す。福島では、住民が避難指示区域に帰還できるにさまざまな努力が払われてきた。これには、居住区域や農地、道路等の除染が含まれる。しかしながら、森林はごく限られた面積に限定して除染が計画され、実施されてきた。そして、その目的はチェルノブイリでの対策と同じく、人の故聴を低減することである。発表では、チェルノプイリ立入禁止区域と福島の避難指示区域で見られる代表的な森林で放射性セシウム濃度のデータと変化傾向を示し、今後の傾向を予想する上で重要なプロセスを特定する。そして、福島の林業活性化の見通しについて議論する。キーワード：森林生態系、福島、チェルノブイリ、放射性核種の動態、林業の活性化
S-5
Dynamics of radionuclides throughout the river network in
Chernobyl and Fukushima
Yasunori Igarashi *' , Member of a Project of SATREPS program "Strengthening of the Environmental Radiation
Control and Legislative Basis for the Environmental Remediation of Radioactively Contaminated Sites" 12345 1 Institute of Environmental Radioactivity, Fukushima University, ² Faculty of Symbiotic Systems Science and Technology, Fukushima University 3  Graduate School of Symbiotic Systems Science and Technology, Fukushima University ' University of Tsukuba 5 Fukushima Medical University * Corresponding author: y-igarashi@ipc.fukushima-u.ac.jp Radionuclides which was released into the atmosphere due to a nuclear accident or the like are deposited on the ground surface and then transported to the downstream of the river basin via a river network as dissolved and suspended forms. For this reason, rivers are known to play an important role in redistributing radionuclides deposited on the ground surface. Inside the Chernobyl exclusion zone, the radionuclides concentration in rivers has been measured continuously since the 1986 nuclear accident. Results of long-term observations over more than 30 years in Chernobyl rivers indicate that (1) dissolved and suspended concentrations in river water declined significantly in the first 5-7 years, followed by a gradual decline over the next 30 years, and the trend continues even now, and that (2) the solid-liquid distribution ratio increases with time. Until now, the concentration of radioactive cesium in rivers has been measured in various rivers in Fukushima. From numerous previous studies, similarities and differences from Chernobyl have become apparent. At the symposium, we would like to introduce the latest research on radioactive materials flowing in rivers, comparing Chernobyl restricted areas with Fukushima. Keywords : Chernobyl and Fukushima, river water system, radionuclides dynamics
チェルノブイリと福島における河川網を介した放射性物質の動態
五十嵐康記*、SATREPS課題「チェルノプイリ災害後の環境管理支援技術の確立」参加メンバー12345 ¹福島大学環境放射能研究所²福島大学共生システム理工学類・大学院共生システム理工学研究科³福島大学大学院共生システム理工学研究科*筑波大学5福島県立医科大学*責任著者: y-igarashi@ipc.fukushima-u.ac.jp原発事故等により大気中に放出された放射性物質は、地表面に沈着したのち落存態および懸濁態として河川網を介して流域の下流側に輸送される。このため、河川は地表面に沈着した放射性物質の再拡散に重要な役割を果たす事が知られています。チェルノプイリ規制区域内では、1986年の原発事故以降、河川中の放射性物質濃度の計測が継続的に行われています。チェルノブイリの河川における30年以上にわたる長期観測の結果から、(1)河川水中の溶存態・懸濁態濃度は最初の5-7数年で大きく低下し、その後の30年近くに渡り緩やかな低下傾向が現在でも続いている事、(2)固液分配比は時間経過と伴に増加している事が分かっています。これまで福島では様々な河川で、河川中の放射性セシウム濃度の計測がおこなわれてきています。その結果、チェルノプイリとの類似点・相違点が明らかになってきています。シンポジウムでは、河川中を流れる放射性物質に関する最新研究を、チェルノプイリ規制区域と福島とを対比させながらわかりやすく紹介します。キーワード：チェルノブイリと福島、河川網、放射性物質の動態
S-6
Temporal trends of radio-cesium concentration in the marine environment after the Chernobyl and Fukushima Daiichi Nuclear
Power Plant accidents
Hyoe Takata* 1 ¹ Institute of Environmental Radioactivity, Fukushima University *Corresponding author: h.takata@ier.fukushima-u.ac.jp Baltic and Black Seas are mostly affected areas by the accident at the Chernobyl nuclear power plant (CNPP) in 1986. Since Fukushima Daiichi nuclear power plant (FDNPP) is located on the coast of the North Pacific Ocean in east Japan, its accident resulted in the release of large amounts of radiocesium to the surrounding coastal marine environment (i.e. the waters off Fukushima and neighboring prefectures). The temporal change of radiocaesium concentration in seawater after both accidents was largely dependent on their submarine topography: The Baltic and Black Seas are semi-closed basins, while the waters off Fukushima and neighboring prefectures is directly connected to open-water. Although concentration of radioacesium ( 137 Cs) in the surface water of the Baltic Sea (central part) continuously decreased, the values in 1994, eight years after the accident, were even higher than pre-accident level in 1985. On the other hand, in the waters off Fukushima and neighboring prefectures 137Cs concentrations in 2019, eight years after the accident, are approaching the pre-accident levels of 2010. The quick decrease is attributable to the intrusion or mixing of water masses with low 137Cs. Keywords : Baltic Sea, Black Sea, the waters off Fukushima Prefecture, topography
チェルノブイリと福島第一原発事故後の海洋環境中の放射性セシウ
ム濃度の変遷
高田兵衛* ¹
'福島大学環境放射能研究所*責任著者: h.takata@ier.fukushima-u.ac.jpチェルノプイリ原発事故の影響を大きく受けた主な海域はバルト海と黒海である。福島第一原発事故の影響を受けた海域は東日本の北太平洋側沿岸である。両事故の影響を受けた海域の大きな違いはその海洋構造にある。バルト海及び黒海は閉鎖性海域である一方、東日本の太平洋側沿岸は直接北太平洋と広がる開放性海域である。これらの異なる海洋構造が、事故後の海洋環境中での放射性セシウムの濃度変遷に影響を与えている要因の一つと考える。バルト海（中央部）表層の放射性セシウム濃度（セシウム-137）はチェルノプイリ原発事故以降、着実に減少しているものの、事故から8年経過した1994年時点では事故前の数値よりも高い値であった。その一方、東日本の北太平洋側では福島第一原発事故以降の事故から、同じ8年後の2019年ではほぼ事故前の数値に近づいていた。この早い減少は開放性海域での海洋の希釈拡散効果が大きいためと考える。キーワード：バルト海、黒海、福島県沿岸海域、海洋構造