Study on migration mechanism of radiocesium in the mountain stream of Evacuation Instruction area and the removal of radiocesium accumulated in the fish body

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K12200
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Ibaraki University
• Principal Investigator: Nakazato Ryoji 茨城大学, 広域水圏環境科学教育研究センター, 准教授 (30292410)
• Research Collaborator: KARUBE Zin'ichi 茨城大学, 広域水圏環境科学教育研究センター, 助教 ; SUZUKI Hitone 室原川, 高瀬川漁業協同組合, 幹事 ; KATO Kenichi 室原川, 高瀬川漁業協同組合, 幹事
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: ヤマメ / イワナ / 標識放流実験 / モニタリング / 山地渓流 / 放射性セシウム / 帰還困難区域

Outline of Final Research Achievements

The 137Cs concentrations of two species of mountain stream fish, masu salmon and white-spotted char were monitored on the sites with different air dose rate, in the Evacuation Instruction area during 2015-2018. The 137Cs concentrations of both fish were significantly higher in the sites with higher air dose rates than in lower sites. In all sites, 137Cs concentrations of both species collected during sampling period did not decrease clearly. Therefore, 137Cs concentrations of both species were supposed to reach equilibrium state in the present when approximately seven years passed from the nuclear accident at the FDNPP.
As results of the rearing experiments of masu salmon and white-spotted char involving 137Cs,the rearing method using artificial feed including the zeolite was effective for removal of 137Cs accumulated in the fish body.

Free Research Field

陸水生態学