The chemical form of organic radiocesium in the agricultural environment

• Project/Area Number: 26520302
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 特設分野
• Research Field: Food Cycle Research
• Research Institution: Fukushima University
• Principal Investigator: Ohse Kenji 福島大学, うつくしまふくしま未来支援センター, 特任准教授 (90396606)
• Co-Investigator(Kenkyū-buntansha): 北山 響 福島大学, うつくしまふくしま未来支援センター, 特任研究員 (40647244) ; 塚田 祥文 福島大学, 環境放射能研究所, 教授 (50715498)
• Project Period (FY): 2014-07-18 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 放射性セシウム / 存在形態 / 土壌 / 河川懸濁物質 / 福島第一原発事故 / 懸濁物質

Outline of Final Research Achievements

The major forms of radiocesium in soil are exchangeable, clay-bound, and organic. “Organic” radiocesium is defined as the fraction that it is not extracted by salt solution but should be solubilized by oxidative decomposition or alkali extraction. In our previous study, organic radiocesium was observed not only in soil but also in the suspended matter of streams. However, the mechanisms by which cesium ions bind with organic matter, the kinds of organic matter that bind with cesium ions, and whether cesium ions bind with organic matter at all remain unknown. In the present study, we aimed to clarify the actual chemical form of radiocesium extracted in the organic form from soil and suspended matter and the kinds of organic matter that bind with radiocesium. From dencity fractionation, chemical fractionation, and chloroform fumigation, it was suggested that most organic radiocesium was contained undecomposed organic matter including microorganism.

Research Products

• [Presentation] 土壌および懸濁物質中の「有機態」放射性セシウムの存在形態 (2015)
  • Author(s): 大瀬健嗣、加藤美紀、北山 響、塚田祥文
  • Organizer: 日本土壌肥料学会年次大会
  • Place of Presentation: 京都大学（京都市左京区）
  • Year and Date: 2015-09-09
• [Presentation] The chemical form of “organic” radiocesium in soil and suspended matter (2014)
  • Author(s): Kenji Ohse, Kyo Kitayama, Chika Suzuki, Akira Kanno, Wakana Horiuchi, Kencho Kawatsu, Hirofumi Tsukada
  • Organizer: The 9th International Symposium on the Natural Radiation Environment
  • Place of Presentation: ホテルニューキャッスル（弘前市）
  • Year and Date: 2014-09-25
• [Presentation] 土壌および懸濁物質中の「有機態」放射性セシウムの存在形態 (2014)
  • Author(s): 大瀬健嗣，鈴木千佳，菅野 章，堀内季奈，加藤美紀，塚田 祥文
  • Organizer: 日本土壌肥料学会
  • Place of Presentation: 東京農工大学
  • Year and Date: 2014-09-10