129I/127I ratios of Scottish sea water taken at ten locations between 2003 and 2005 will be presented. These data constitute the first reported 129I/127I ratios in Scottish sea water since 1992. Iodine isotope ratios as high as 3*10-6 - only a factor of three lower than recent analysis close to the emission source Sellafield (M. Atarashi-Andoh et al., 2005) - were found in Dumfries and Galloway in the south-west of Scotland. This ratio is even higher than the highest result published by Yiou et al. (1994) for samples taken in the Irish Sea in 1992. Ratios in the north-west and north-east of Scotland are about 1*10-7. This result is about a factor of seven higher than the ratio determined by Yiou et al. (1994) in 1992 in the north-east (Lossiemouth) - in agreement with the development of the liquid 129I emissions from Sellafield.
For some locations samples from 2003, 2004 and 2005 were analysed to study the time dependance of the iodine isotope ratios.
Results for Hebridean Island samples agree better in their iodine isotope ratios than in their 129I concentrations. We see this as confirmation that the isotope ratio is the better tracer for ocean current studies than the radionuclide concentration.
Reference: F. Yiou et al., NIM B 92 (1994) 436. M. Atarashi-Andoh et al., GCA 69 (2005) A716.
Acknowledgment: NERC supported the work by paying the first author's salary. S Waldron (SUERC) took samples from the south-west of Scotland and M Miguens-Rodriguez (SUERC) took part in ICP-MS measurements.
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