Speaker
Description
Based on the Euratom Treaty Austria has established a comprehensive and thorough environmental monitoring programme. As part of this programme, the levels of radioactivity are regularly determined in various types of environmental media. Air and air filters are among the most frequently examined environmental media. Within the routine monitoring of air filters the Austrian Agency for Health and Food Safety focuses on the determination via gamma spectrometry. Besides the activity concentrations of gamma emitters, various artificial alpha and beta emitting radionuclides like the Plutonium isotopes or Sr-90 are of interest as well. Consequently, the goal of this project was to determine the activity concentrations of the alpha-emitting Plutonium isotopes Pu-239 and Pu-240, Am-241 and Sr-90 in Viennese aerosol filters. Due to the very low concentrations of these radionuclides in air (on the order of a few nBq/m³), the analysis of aerosol filters is particularly challenging. In order to achieve values above the limit of detection, filters from a high-volume air sampler with a throughput of about 700 m³/h and a sampling interval of one week were analysed. During the sampling process naturally occurring nuclides like Pb-210 become highly enriched and interfere with the radiochemical separation. Thus, the analysis becomes even more complex. In order to overcome these challenges, a sequential radionuclide separation procedure using extraction chromatographic resins was applied. While Sr-90 was measured using LSC, the Pu-isotopes were determined by alpha spectrometry. In addition to these radiometric methods, ICP-MS/MS was also used for the determination of Pu-239. The radiochemical separation procedure as well as the results of this project will be presented.
This project was funded by the Federal Ministry of Agriculture, Forestry, Regions and Water Management of Austria.