Distribution of ¹²⁷I and ¹²⁹I in precipitation at high European latitudes

We here present the most extensive data set on the distribution of ¹²⁷I and ¹²⁹I in precipitation (rain and snow) covering the period 2000-2006 and European latitudes 55°N-68°N. Our results indicate a wide variation in the concentrations and fluxes of the two isotopes associated with generally higher values at near coastal sites compared to the inland ones. Total wet-related annual deposition of ¹²⁷I and ¹²⁹I on Sweden and Denmark is estimated at about 1.2 × 10 ⁹ g and 60 g respectively. The average annual ¹²⁹I wet deposition accounts for <1% and <0.05% of the total annual gaseous and liquid, respectively, discharges from the Sellafiled and La Hague Facilities. The ¹²⁷I annual wet deposition represents <1% of the estimated global oceanic iodine flux. Air mass trajectories suggest that events of enhanced ¹²⁹I in precipitation are closely related to southwesterly weather fronts from regions of elevated concentrations.