Distribution, dynamics, and fate of radiocesium derived from FDNPP accident in the ocean

This paper gives an overview of the research results obtained in 10 years after accident at Fukushima Daiichi Nuclear Power Plant (FDNPP), focusing on distribution and dynamics 137Cs, which is one major accident-derived radionuclides. Immediately FDNPP accident, 8–21 PBq 137Cs was transported to ocean mainly due direct discharge ocean, deposition via atmosphere. seawater traveled eastward surface North Pacific Ocean along Kuroshio Extension over a period several years. Some also recirculated western margin subtropical intermediate layer. The concentration radiocesium marine organisms increased immediately then decreased time. brackish demersal fishes slower rate than surface-dwelling fish. amount accumulated seafloor only about 1% (0.2PBq) carried but it remains sediments coastal area for long time gradually migrates ecosystems near seafloor.