Dispersion of Fukushima radionuclides in the global atmosphere and the ocean

Large quantities of radionuclides were released in March–April 2011 during the accident of the Fukushima Dai-ichi Nuclear Power Plant to the atmosphere and the ocean. Atmospheric and marine modeling has been carried out to predict the dispersion of radionuclides worldwide, to compare the predicted and measured radionuclide concentrations, and to assess the impact of the accident on the environment. Atmospheric Lagrangian dispersion modeling was used to simulate the dispersion of 137Cs over America and Europe. Global ocean circulation model was applied to predict the dispersion of 137Cs in the Pacific Ocean. The measured and simulated 137Cs concentrations in atmospheric aerosols and in seawater are compared with global fallout and the Chernobyl accident, which represent the main sources of the pre-Fukushima radionuclide background in the environment. The radionuclide concentrations in the atmosphere have been negligible when compared with the Chernobyl levels. The maximum 137Cs concentration in surface waters of the open Pacific Ocean will be around 20Bq/m3. The plume will reach the US coast 4–5y after the accident, however, the levels will be below 3Bq/m3. All the North Pacific Ocean will be labeled with Fukushima 137Cs 10y after the accident with concentration bellow 1Bq/m3. [Display omitted] •Modeling of Fukushima radionuclides in the atmosphere.•Modeling of Fukushima radionuclides in the Pacific.•Comparison of the Fukushima radionuclide impact with global fallout.•Comparison of Fukushima and Chernobyl radionuclide releases.