Iodine-129 in the European Environment

Due to former atmospheric nuclear weapon tests, accidents in nuclear facilities and releases from nuclear reprocessing plants, the natural occurrence of the radionuclide 129I has been affected on a long term scale by human activities. Particularly in Western Europe, these changes are continuing due to discharges from the nuclear reprocessing plants La Hague and Sellafield. A survey is given on the environmental abundances of 129I and 127I in the North Sea, the Northeast Atlantic, as well as on the atmospheric transport of iodine isotopes from the sea to the continent and their pathways to animals and man. Today, the environmental 129I /127I isotope ratios range from 10-10 to 10-6 and are far above the pre-nuclear ratio of ∼10-12. The iodine isotopes are in severe disequilibrium in the different environmental compartments and serve as tracers of the complex environmental chemistry of iodine. (author)