Long-Lived Radionuclides in the Environment:

Abstract: Results are presented from an ongoing project to study the status and behavior of 129I and 127I in the environment. 129I and 127I 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 129I in rain, 129I annual deposition densities were determined for the time period from 1997- 1999. We conclude that 129I 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, 129I deposition densities at various places of Europe were determined. Thereby, the 129I natural equilibrium deposition density as well as that of the fall-out from atmospheric weapon tests was estimated. Elevated 129I abundances in Ukrainian soils contaminated by Chernobyl fall-out provide a basis for retrospective dosimetry of the radiation exposure due to 131I. Soil profiles from Germany exhibit the influence of ongoing emissions from European reprocessing plants and demonstrate the complexity of iodine migration. Biospheric 129I/127I 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 129I through the environment to man are considered necessary