Geochemical cycles in sea environments around the Japanese Archipelago from distributions of multi-radionuclides

• Project/Area Number: 15K00518
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Kanazawa University
• Principal Investigator: Inoue Mutsuo 金沢大学, 環日本海域環境研究センター, 准教授 (60283090)
• Co-Investigator(Kenkyū-buntansha): 山本 政儀 金沢大学, 理工研究域, 特任教授 (10121295) ; 長尾 誠也 金沢大学, 環日本海域環境研究センター, 教授 (20343014) ; 浜島 靖典 金沢大学, 環日本海域環境研究センター, 准教授 (60172970)
• Co-Investigator(Renkei-kenkyūsha): FUJIMOTO Ken 国立研究開発法人 水産研究・教育機構, 中央水産研究所, 研究員 (20371841)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2015: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 放射性核種 / ガンマ線計測 / 日本海 / 物質循環 / 海洋化学

Outline of Final Research Achievements

Soluble and reactive radionuclides (Ra-226, Ra-228, Cs-134, Cs-137, Th-228, and Th-234) in seawater have been used as powerful tracers to investigate geochemical cycles in marine environments. By employing low-background gamma-spectrometry, we conduct fine-resolution observations of spatial and seasonal variations of these radionuclides in the Sea of Japan (and the neighboring East China Sea and Okhotsk Sea), and assess the circulation patterns of water masses and particles. Furthermore, the migration of Ra-228 readily explained the expanding pattern of the 2011 Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident-derived radiocesium around the Japanese Archipelago.

Research Products

• [Journal Article] Spatial variations of 226 Ra, 228 Ra, 134 Cs, and 137 Cs concentrations in western and southern waters off the Korean Peninsula in July 2014 (2018)
  • Author(s): Inoue M.、Shirotani Y.、Nagao S.、Aramaki T.、Kim Y.I.、Hayakawa K.
  • Journal Title: Journal of Environmental Radioactivity Volume: 182 Pages: 151-156
  • DOI: 10.1016/j.jenvrad.2017.11.020
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Temporal and spatial variations of 134 Cs and 137 Cs levels in the Sea of Japan and Pacific coastal region: Implications for dispersion of FDNPP-derived radiocesium (2018)
  • Author(s): Inoue M.、Shirotani Y.、Yamashita S.、Takata H.、Kofuji H.、Ambe D.、Honda N.、Yagi Y.、Nagao S.
  • Journal Title: Journal of Environmental Radioactivity Volume: 182 Pages: 142-150
  • DOI: 10.1016/j.jenvrad.2017.11.032
  • Peer Reviewed
• [Journal Article] Spatial variation in low-level 134Cs in the coastal sediments off central Honshu in the Sea of Japan: implications for delivery, migration, and redistribution patterns (2017)
  • Author(s): Inoue M.、Uemura H.、Kofuji H.、Fujimoto K.、Takata H.、Shirotani Y.、Kudo N.、Nagao S.
  • Journal Title: Journal of Oceanography Volume: 73 Issue: 5 Pages: 571-584
  • DOI: 10.1007/s10872-017-0437-x
  • Peer Reviewed
• [Journal Article] Simple 40K removal by acidified water leaching for estimating low levels of radiocesium in fishery products following Fukushima Dai-ichi Nuclear Power Plant accident. (2017)
  • Author(s): Inoue, M., Yamashita, S., Fujimoto, K., Kofuji, H., Miki, S., Nagao, S.,
  • Journal Title: Appl. Radiat. Isotopes, Volume: 120 Pages: 17-21
  • DOI: 10.1016/j.apradiso.2016.11.008
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Migration area of the Tsushima Warm Current Branches within the Sea of Japan: Implications from transport of 228Ra. (2017)
  • Author(s): Inoue, M., Y. Shirotani, Furusawa, Y., Fujimoto, K., Kofuji, H., Yoshida, K., Nagao, S., Yamamoto, M., Hamajima, Y., Honda, N., Morimoto, A., Takikawa, T., Shiomoto, A., Isoda, Y. and Minakawa, M.
  • Journal Title: Continental Shelf Research Volume: in press Pages: 167-174
  • DOI: 10.1016/j.csr.2016.08.010
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] 日本海放射能調査および海洋研究への適用-中央水産研究所「蒼鷹丸」調査航海を例にとって- (2017)
  • Author(s): 井上睦夫・藤本 賢・森田貴己
  • Journal Title: 日本海域研究 Volume: 48 Pages: 63-70
  • NAID: 120006226761
  • Peer Reviewed
• [Presentation] Vertical profiles of FDNPP-derived radiocesium concentrations in southwestern Okhotsk Sea waters. (2017)
  • Author(s): M. Inoue, T. Morokado, K. Fujimoto, S. Miki, H. Kofuji, Y. Isoda, S. Nagao
  • Organizer: 6th Asia‐Pacific Symposium on Radiochemistry
  • Int'l Joint Research
• [Presentation] Low-levels of 134Cs in riverine suspended solids discharged to coastal areas off central Honshu in the Sea of Japan. (2017)
  • Author(s): M. Inoue, S. Yoneoka, S. Ochiai, T. Morokado, H. Uemura, S. Nagao.
  • Organizer: 6th Asia‐Pacific Symposium on Radiochemistry
  • Int'l Joint Research
• [Presentation] 新潟沿岸～沖合堆積物における福島原子力発電所事故由来134Csの空間分布 (2016)
  • Author(s): 井上睦夫、上村宙輝、長尾誠也、米岡修一郎、濱島靖典、落合伸也、城谷勇陛、糸野妙子、山本政儀、藤本賢
  • Organizer: 海洋学会
  • Place of Presentation: 東京大学
  • Year and Date: 2016-03-17
• [Presentation] 北太平洋北西部表層におけるFDNPP起源の 放射性セシウムの分布 (2016)
  • Author(s): 城谷勇陛・井上睦夫・長尾誠也・小藤久毅・西岡純
  • Organizer: 海洋学会
  • Place of Presentation: 東京大学
  • Year and Date: 2016-03-17
• [Presentation] 東シナ海から日本海表層における228Th/228Ra比の水平分布および季節変動 (2015)
  • Author(s): 城谷勇陛、井上睦夫、長尾誠也、山本政儀、浜島靖典、古澤佑一、小藤久毅、本多直人、森本明彦、滝川哲太郎、藤本賢、早川和一
  • Organizer: 放射化学討論会
  • Place of Presentation: 東北大学 (仙台)
  • Year and Date: 2015-09-26
• [Presentation] 簡便な40K 浸出除去法を利用した海産物試料の低レベル134Cs、137Cs 濃度の測定 (2015)
  • Author(s): 山下詩央里、井上睦夫、藤本賢、長尾誠也、小藤久毅、浜島靖典、山本政儀
  • Organizer: 放射化学討論会
  • Place of Presentation: 東北大学 (仙台)
  • Year and Date: 2015-09-26
• [Presentation] 新潟沿岸～沖合堆積物における福島原発事故由来134Csの空間分布 (2015)
  • Author(s): 上村宙輝、井上睦夫、藤本賢、米岡修一郎、長尾誠也、濱島靖典、落合伸也、糸野妙子、山本政儀
  • Organizer: 放射化学討論会
  • Place of Presentation: 東北大学 (仙台)
  • Year and Date: 2015-09-25
• [Presentation] Migration pattern of the Tsushima Warm Current within/around the Sea of Japan: Implications from transport of 228Ra (2015)
  • Author(s): M. Inoue, Y. Shirotani, Y. Furusawa, K. Fujimoto, H. Kofuji, K. Yoshida, S. Nagao, M. Yamamoto, Y. Hamajima, N. Honda, M. Minakawa, A. Shiomoto, Y. Isoda, K. Hayakawa
  • Organizer: 18th Pacific-Asian Marginal Seas Meeting
  • Place of Presentation: Naha, Okinawa
  • Year and Date: 2015-04-21