Study of the Biological Effect of Soil Sterilization on The Radioactive Cesium Transfer to Plants

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K00600
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Modeling and technologies for environmental conservation and remediation
• Research Institution: Kyoto University
• Principal Investigator: KINOUCHI Tadatoshi 京都大学, 複合原子力科学研究所, 講師 (90301457)
• Co-Investigator(Kenkyū-buntansha): 小林 優 京都大学, 農学研究科, 准教授 (60281101)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 放射性セシウム / ファイトレメディエーション / 土壌汚染 / 藻類 / 除染

Outline of Final Research Achievements

Bioremediation (BRM) is expected as a decontamination measure for soil contaminated with radioactive cesium (Cs) released by the Fukushima Daiichi Nuclear Power Plant accident. In order to investigate the effect of soil microorganisms on BRM, we cultivated the radish on sterilized contaminated soil and observed its Cs absorption rate. As a result, the Cs absorption rate of the radish increased up to 1%. Since it was suggested that Cs which had been assimilated by microorganisms became available via sterilization for uptake by the radish, an investigation was started to confirm the assimilation mode of Cs in the microorganisms. As a result, it was revealed that microalgae cultured under a wavelength range of 400-500 nm especially assimilated Cs. Therefore, it has been shown that it is possible to perform BRM efficiently under this specific wavelength.

Free Research Field

放射線生化学

Academic Significance and Societal Importance of the Research Achievements

バイオレメディエーション（BRM）は、農地特有の生産能力を可能な限りそのままの状態で残せる低コストの原位置浄化法として期待されているが、水耕栽培では培養液中のCsを20%程度吸収するヒマワリでさえ、実際にCs汚染した土壌で栽培すると、その吸収率は0.04%程度で、実用性が見出せなかった。我々はBRMにおける水耕栽培と土耕栽培の効率の違いの原因として土壌微生物に着目し、汚染土壌を滅菌することによってその吸収率を最大1%まで上昇させることに成功した。BRM効果が改善された理由として、結合態として土壌微生物に収着されていたCsが滅菌処理によって可給態となったことを明らかにした。