Publication on sources and spreading of radionuclides in the North Atlantic and Arctic region

Yongqi Gao, Helge Drange, Ola M. Johannessen and Lasse H. Pettersson have published a study on the sources and pathways of 90-Sr in the North Atlantic–Arctic region under present day and global warming condition in Journal of Environmental Radioactivity.

The publication addresses the spatial and temporal distributions of the anthropogenic radionuclides 137-Cs and 90-Sr, originating from nuclear bomb testing, the Sellafield reprocessing plant in the Irish Sea (UK), and from the Ob and Yenisey river discharges to the Arctic Ocean, have been simulated using the global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). MICOM has been extensively used for climate simulations at the Nansen Center. The physical model is forced with daily atmospheric re-analysis fields for the period of 1948–1999. Comparison of the temporal evolution of the observed and the simulated concentrations of 90-Sr has been performed in the Kara Sea (see figure).

The relative contributions of the different sources on the temporal and spatial distributions of the surface 90-Sr are quantified over the simulated period. It follows that the Ob river discharge dominated the surface 90-Sr over most of the Arctic Ocean and along the eastern and western coasts of Greenland before 1960. During the period of 1980– 1990, the atmospheric fallout and the Ob river discharge were equally important for the 90-Sr distribution in the Arctic Ocean. Furthermore, an attempt has been made to explore the possible dispersion of accidental released 90-Sr from the Ob and Yenisey rivers under a global warming scenario (2 * CO2). The difference between the present-day and the global warming scenario runs indicates that more of the released 90Sr from the Ob and Yenisey rivers is confined to the Arctic Ocean in the global warming run, particularly in the near coastal, non-European part of the Arctic Ocean.

The study has been supported by the EU-project “Simulation Scenarios for Potential Radioactive Spreading in the 21st Century from Rivers and External Sources in the Russian Arctic Coastal Zone (RADARC; ICA2-CT-2000-10037)” and supported by the Norwegian Research Council founded project “Arctic Radioactive Contaminations (ARC)”.

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