Measurement of 236U, 137Cs, and 129I in the Labrador and Beaufort Seas

Abstract

The first comprehensive analysis of surface waters in the Labrador Sea for 236U was completed via Accelerator Mass Spectrometry. Through the analysis of 236U the method for AMS measurement was fine-tuned to allow for more precise results. Surface samples for the anthropogenic isotopes 137Cs and 129I were also collected along with two depth profiles of 129I. Samples were also collected in the Beaufort Sea and analyzed for the aforementioned isotopes. It was found that anthropogenic 129I from reprocessing plants is easily discernible at different concentrations among water bodies in both the Labrador and Beaufort Sea. 137Cs in surface waters is close to global fallout levels with no discernable influence from reprocessing plant inputs, but follows a similar trend to that of 129I with depth in the Beaufort Sea. 236U among surface waters in the Labrador Sea did not follow the same trends as 129I but had concentrations indicative of a mix of global fallout as well as reprocessing plant influenced waters. 236U samples from the Beaufort Sea were contaminated by an unknown source of 236U and were inconclusive but were reproducible and allowed for continued development of the AMS analysis methodology.