Levels of 137Cs and 40K in marine superficial sediments near the Angra Nuclear Power Plant (Angra dos Reis, SE Brazil)

This study evaluated the spatial distribution of two environmentally relevant radionuclides, Cs-137 and K-40, in marine superficial sediments around the Angra Nuclear Power Plant, the only Brazilian nuclear power plant complex, thus establishing a baseline for bottom sediments, given the international importance of environmental monitoring around nuclear facilities. It was observed that these radionuclides are mostly present in the muddy sediments as a result of their stronger association with its fine-grained fraction, and that their lowest levels are located around the liquid effluent discharge of the plant, as a consequence of the prevented deposition of fine sediments due to the strong discharge water flux. The comparison of the Cs-137 activities in the region with other locations in the world showed that the presence of this artificial nuclide is due to the atmospheric fallout from past nuclear tests made during the ColdWar, not to the nuclear power plant activities.