[2A13-19] Environmental Radioactivity and Monitoring 3

[2A17] Investigation on distribution of radioactive substances in Fukushima

(17)Long-term behavior of radiocesium-137 in river sediments in eastern Japan

*Yuichi Onda¹, Tang Chen¹, Gao Xiang¹, Keisuke Taniguchi¹, Yukio Takeuchi², Momo Kurihara³, Katsumi Hirose¹ (1. CRiED, University of Tsukuba, 2. Fukushima Pref. Env. Creation C., 3. QST)

Keywords:Cs-137, river sediment

We summarized particle-size collected Cs concentration of bottom sediment samples (MOE, 461 sites), SS samples (30 sites) around Fukushima affected area. We found the logarithm of the initial inventory was found to be negatively correlated with the rate of decline of Cs-137 in the sediment. The sediment of Cs-137 and the Kdac of SS were found to be similar over time. These results suggest that initial fallout conditions and temporal factors also influence the decline in Cs-137 contamination levels in river systems.