Vertical profile of artificial radionuclide concentrations in the Central Arctic Ocean

The artificial radionuclides ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu and ²⁴¹Am have been measured in eight water samples collected in 1979, at intervals from surface to bottom, through the ice at the LOREX satellite camp SS near the North Pole. Differences in the concentrations and ratios of these nuclides, compared with values measured, over time, in the various water masses that flow into the Arctic Ocean, can be used as semi-independent checks on rates of flow to the LOREX stations and on residence times in the Arctic Ocean. An unexpected finding was that water labelled with low-level liquid waste from the Windscale plant on the Irish Sea is a major component of the 1500 m LOREX sample, and has reached there in no more than eight to ten years. Even from this one station in the Polar Ocean, estimation of the inventories of the various radionuclides is good enough to emphasize the importance of horizontal advection of the various supply terms to the Arctic.