AMS measurements of 129I in seawater around Iceland and the Irminger Sea

Abstract

Large amounts of iodine-129 were, and still are, released into the environment from nuclear facilities, in particular from two reprocessing facilities located on the east coast of the North Atlantic Ocean (Sellafield and La Hague). The main transport path of the releases from the two facilities is through the North Atlantic Current (NAC) and subsequently the Norwegian Coastal Current (NCC) to the Arctic Ocean. Iceland lies on the Scotland–Greenland ridge, which separates the Atlantic and Arctic oceans. 129I data available in that area are scarce despite their importance in modeling 129I dispersion through the North Atlantic and Arctic Oceans. For this reason, we have determined the 129I/127I ratio in seawater samples by means of Accelerator Mass Spectrometry (AMS) from three locations at the Iceland and Irminger Basins at different depths (from surface to 1000m) in order to study the transport pathways of the anthropogenic releases to the waters. The measured 129I/127I ratios, compared to the pre-anthropogenic 129I/127I value, show the strong influence of the artificial 129I discharges in the North Atlantic waters.