development of low lwvel radiosilver and cesium retio measurement of biosamples in fukushima open sea and application to elucidation of transition process

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K00520
• 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: HAMAJIMA Yasunori 金沢大学, 環日本海域環境研究センター, 准教授 (60172970)
• Co-Investigator(Kenkyū-buntansha): 青山 道夫 福島大学, 学内共同利用施設等, 特任教授 (80343896)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 極微弱放射線測定 / 放射性銀 / 放射性セシウム / 海生生物 / 井戸型HPGe / サム効果 / 計数効率

Outline of Final Research Achievements

I Development of precise quantification method of radioactive nuclides with coincidence summing effect: We measured the efficiency of 9 nuclides mixed standard source and standard radioactive Ag source in HPGe. We find the total efficiency curve as a function of energy, have developed a method for estimating peak efficiency of all nuclides with summing. Our method for radioactive Ag with summing almost agrees with the measured value, and its effectiveness has been demonstrated.
II Origin of radioactive silver and cause of transition and accumulation to the ecosystems: We collected marine biological samples, sea water, sediments, submarine soil, and measured extremely low activity after pretreatment. Radioactive cesium was detected from all samples, and weak radioactive Ag was observed from a part of biological samples and organic fraction of the seabed soil, but it was not detected from others. Transfer of radioactive Ag to marine organisms was be due to ingestion of organic fraction.

Free Research Field

核・放射化学，微弱放射線測定