Retrospective measurements of airborne 129Iodine in Austria

The knowledge about the distribution of anthropogenic 129I is crucial for a successful establishment of transport mechanisms, fate and behaviour in the environment. In present study, the historical record of dry deposition of 129I in Austria over four decades back to the 1960s is reconstructed. The 129I/127I isotopic ratio of the order of 10−9–10−7 in airborne particles revealed a prominent anthropogenic 129I signature. The time profile of airborne 129I follows directly the pattern of the gaseous emissions from European reprocessing plants. Furthermore, temporal variations of 129I were traced monthly over two years. The potential risks of internal exposure to 129I are associated with both inhalation and ingestion. Since dose via inhalation was found insignificant, the thyroid equivalent dose from the internal exposure of 129I using a value of 10−8 for the isotopic ratio 129I/127I in the thyroid and ICRP reference man was calculated. The corresponding thyroid cancer risk factor of 10−11 for an adult from life-time exposure is one order of magnitude higher than for a 1-year old child. Due to low radiation toxicity of 129I the annual dose is 8 × 104 times lower than the dose limit of the National Research Council, USA which is 0.04 mSv y−1 to whole body or any organ for a combined beta and photon emitting radionuclide.

► We report on retrospective time profile of Iodine-129 in the air of Austria.
► 129I/127I of the order of 10−9–10−7 revealed anthropogenic 129I signature.
► 129I time series followed pattern of gaseous emissions from European reprocessing plants.
► Temporal variations of 129I and 7Be were traced monthly during 2001–2002.
► Radiological impact of 129I was found insignificant.