Fukushima 137Cs releases dispersion modelling over the Pacific Ocean. Comparisons of models with water, sediment and biota data

Abstract

A number of marine radionuclide dispersion models (both Eulerian and Lagrangian) were applied to simulate ¹³⁷Cs releases from Fukushima Daiichi nuclear power plant accident in 2011 over the Pacific at oceanic scale. Simulations extended over two years and both direct releases into the ocean and deposition of atmospheric releases on the ocean surface were considered. Dispersion models included an embedded biological uptake model (BUM). Three types of BUMs were used: equilibrium, dynamic and allometric. Model results were compared with ¹³⁷Cs measurements in water (surface, intermediate and deep layers), sediment and biota (zooplankton, non-piscivorous and piscivorous fish). A reasonable agreement in model/model and model/data comparisons was obtained.

Keywords: Biological uptake model; Caesium; Dispersion model; Fukushima-Daiichi accident; Ocean; Sediment.