Status and future of radiocesium in the seafloor off Fukushima

Otosaka, Shigeyoshi*  ; Aono, Tatsuo*; Fukuda, Miho*; Kambayashi, Shota*; Misono, Toshiharu   ; Dohi, Terumi   ; Tsuruta, Tadahiko  ; Suzuki, Takashi  ; Takahashi, Yoshio*; Sugihara, Naoko*; Obata, Hajime*

While the amount of cesium-137 (Cs: half-life 30.1 years) accumulated on the seabed due to the accident of the Fukushima Daiichi Nuclear Power Plant (0.1-0.2 PBq) is only about 1 to 2% of the total amount of Cs transported to the ocean, it has been reported that it will remain for a long time in the coastal areas. On the other hand, long-term migration process of the sedimentary radiocesium and the impact on the ecosystem near the seafloor remain unknown. In this presentation, we will give an overview of the distribution and behavior of Cs, especially on the seafloor along the coast of Fukushima, and report the latest results on the processes I the seafloor that should be considered on decadal timescale.