Long-Lived Radionuclides in the Environment: The Case of Iodine-129

Results are presented from an ongoing project to study the status and behavior of I and I in the environment. I and I abundances were investigated in precipitation, surface and ground waters from Lower Saxony, Germany, and in soil samples from various European locations. From the analysis of I in rain, I annual deposition densities were determined for the time period from 19971999. We conclude that I deposition rates in Switzerland and Germany increased by three orders of magnitude since 1950 and changed just little after 1987. From the analysis of soils, I deposition densities at various places of Europe were determined. Thereby, the I natural equilibrium deposition density as well as that of the fall-out from atmospheric weapon tests was estimated. Elevated I abundances in Ukrainian soils contaminated by Chernobyl fall-out provide a basis for retrospective dosimetry of the radiation exposure due to I. Soil profiles from Germany exhibit the influence of ongoing emissions from European reprocessing plants and demonstrate the complexity of iodine migration. Biospheric I/I ratios in Germany are an order of magnitude lower than in precipitation and . Because of the disequilibrium of iodine isotopes in the different compartments further detailed investigations of the pathways of I through the environment to man are considered necessary.