Dissolved-form Cs-137 leaching associated with DOC leaching in headwater streams

恩田 裕一*; 川野 泰地*; 永田 祐太郎*; 高橋 純子*; 榊原 孝一*; 加藤 弘亮*; 五十嵐 康記*; 新里 忠史  

Onda, Yuichi*; Kawano, Yasuchi*; Nagata, Yutaro*; Takahashi, Junko*; Sakakibara, Koichi*; Kato, Hiroaki*; Igarashi, Yasunori*; Niizato, Tadafumi

The Fukushima Daiichi Nuclear Power Plant accident occurred on March 11, 2011, and a large amount of Cs-137 was released into the environment. When Cs-137 is discharged downstream through rivers, its concentration is important because dissolved cesium is easily transferred to aquatic organisms such as fish. The purpose of this study is to investigate how biogeochemical activities are involved in the formation of dissolved Cs-137 concentrations in the headwaters of the watershed of Fukushima Prefecture. The results indicate that the concentration of dissolved Cs-137 is formed by the decomposition of coarse organic matters in the watershed. Thus, investigating the formation mechanism of dissolved Cs-137 concentration can be an important tracer for elucidating water and material cycles and biogeochemical activities in the terrestrial environment.