Mapping and prediction of geogenic radon potential in Germany

Mapping and prediction of geogenic radon potential in Germany is based on t he results of standardized field measurements, taking into account gas rado n activity concentration, gas permeability and the geological situation as the major parameters for its classification and regionalisation. In a first approach, areas with metamorphic and silica-l ich volcanic cocks as well a s with distinct Paleozoic sedimentary rocks, characterized by enhanced radi onuclide contents, were surveyed in regional scale. The sampling grid for t hese investigation areas was 5 x 5 km or denser, depending on the specific geological situation. For the major part of the total area of Germany which is covered by younger Mesozoic to Cenozoic rock units, the expected geogen ic radon potential is medium-to-low. The sampling grid within these larger lithologically homogeneous areas was therefore more widely spaced. The regi onalisation of the measured radon values was calculated on the basis of ras terized geological maps, taking into account the lithological boundaries as delimiting borders for the data interpolation. Such a GIS supported approa ch will allow further regional discrimination by including digital terrain models and soil maps. The obtained radon potential maps serve as a planning aid for government administration to direct further investigations and pre ventive measures. Finally, different techniques for regionalisation accordi ng to administrative boundaries are discussed.