129I Variability in precipitation over Europe

We present results and an overview of studies on 129I in precipitation over Europe during the last decade, covering latitudes 37–70°N. The data show about three orders of magnitude variability in concentrations but without specific correlation to latitude when all Europe is considered. The total amount of 129I provided annually by precipitation over Europe composes only a tiny portion of the annual marine discharge but a significant portion of the gaseous discharges from the nuclear reprocessing facilities. Contribution of gaseous releases seems to be significant, although difficult to estimate. As shown by this study, a unified sampling procedure and systematic measurements of 129I in precipitation throughout Europe are needed to achieve a coherent picture about the loading and sources of 129I in precipitation and the atmosphere.