Emissione di gas radon e concentrazione di gas nel suolo lungo il lineamento periadriatico (Val Pusteria, BZ).

The Agency for the Protection of the Environment of the Bolzano Province carried out a study on Radon gas in the buildings of all the municipalities in the 90’s (Minach et al., 1999). The aim of these measurements was to identify risk areas and to to carry out the mapping of the Radon Indoor (IR). High-risk municipalities are those with emissions> 400 Bq/m3. Some of these municipalities are aligned along the Val Pusteria. In this thesis, starting from this paper, the relationship between the high IR values of the municipalities of the Val Pusteria and the outcropping lithologies was assessed through a multidisciplinary geological study. Furthermore, considering that these municipalities are broadly located along the Periadriatic Lineament we have evaluated the effects of this tectonic line on Radon exhalation. To achieve this goal we have sampled the lithotypes outcropping in the area to assess their chemical composition and radioactivity. We have measured soil gas exhalation in situalong transects across Periadriatic Lineament. Moreover, we have considered grain size effects on Radon emission by means of laboratory measurements. Preliminary results show that the main factor that increase IR is the Periadriatic Lineament and not the lithology. The higher Radon emission in cataclastic zones is related to the increasing of Radon emission with the increasing specific surface area. The "amplification" effect on the Radon gas emanation can be mitigated by the presence of clay-rich alluvial deposits.