Study on transport behavior of radiocesium from river watershed to coastal marine environment and its ecological effects

2014 Fiscal Year Final Research Report

• Project/Area Number: 24310009
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Environmental dynamic analysis
• Research Institution: Kanazawa University
• Principal Investigator: NAGAO Seiya 金沢大学, 環日本海域環境研究センター, 教授 (20343014)
• Co-Investigator(Kenkyū-buntansha): YAMAMOTO Masayoshi 金沢大学, 環日本海域環境研究センター, 教授 (10121295) ; FUKUSHI Keisuke 金沢大学, 環日本海域環境研究センター, 准教授 (90444207) ; KIRISHIMA Akira 東北大学, 多元物質科学研究所, 准教授 (00400424) ; INOUE Mutsuo 金沢大学, 環日本海域環境研究センター, 助教 (60283090)
• Research Collaborator: TOMIHARA Seiichi
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 河川流域 / Cs-137 / Cs-134 / 溶存態 / 懸濁態 / 河川水 / 移行動態

Outline of Final Research Achievements

The secondary dispersion of radiocesium is important to understand the migration behavior of radiocesium (134Cs and 137Cs), released from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident, in river systems running through the areas with widely various radiocesium deposition. This study investigated radiocesium radioactivity in river waters in Abukuma, Same, Natsui, Niida, and Uta Rivers, Japan. The secondary dispersion exhibited that total radioactivity of radiocesium decreased concomitantly with increasing time after the NPP accident at normal flow condition. Higher radioactivity and particulate phase percentage were found at high flow condition caused by rain events. The percentage of particulate phase for May-September 2011 was 20-30 points lower than those after December 2011 at normal flow condition. These results indicate that the supply of radiocesium from the watershed differs from the early stage up to September-December 2011 and from the last stage.

Free Research Field

地球化学