Radon exhalation across the Periadriatic Lineament in the Pustertal/Pusteria Valley (Bolzano, North-Eastern Italy)
- 1Department of Geosciences, University of Padova, Via Gradenigo 6, I-25131 Padova, Italy
- 2Institute of Environmental Geology and Geoengineering, National Research Council, 00015 Rome, Italy
- 3Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi 2, I-40126 Bologna, Italy
- 4National Institute of Geophysics and Volcanology, Via Vigna Murata 605, 00143 Rome, Italy
In the early 90’s, the Environmental Protection Agency of the Bolzano Province (NE Italy) performed a study on Indoor Radon in all the municipalities of the district (Minach et al., 1999). The aim of these measurements was to identify the areas characterized by high Indoor Radon (IR) values to realize an Indoor Radon map. Most of the municipalities that resulted to have average IR values above 400 Bq/m3, thus classified at high risk according to 90/143/EURATOM, are aligned along the Pustertal/Pusteria Valley. In this work, the relation between Radon activity, and the concentrations of other gases in the soil, and geological factors (e.g. lithology, tectonic structures) is investigated along two profiles across the Periadriatic Lineament in the Pustertal/Pusteria Valley. Samples of the petro-volumetrically relevant lithologies of the studied area have been collected, their chemical composition (XRF) and their radionuclides content (high resolution gamma-rays spectrometry) determined. The lithologies include granitoid rocks, orthogneisses, micaschists and phyllites, some of which are characterized by a high activity concentration of natural terrestrial radionuclides. As a consequence, their presence in the study area may potentially increase Radon emission (EC-JRC, 2019). Radon, CO2, CH4, O2, H2 and H2S have been measured in soil gas along the two profiles to investigate the effect of the Periadriatic Lineament (PL) on Radon exhalation. The profiles are located near Mühlen/Molini (P1) and Pfalzen/Falzen (P2), respectively. Preliminary results show two evident Radon peaks of 112 kBq/m3 and118 kBq/m3 along P1, and of 148 kBq/m3 and 157 kBq/m3 along P2. The background values are below 50 kBq/m3. These peaks correspond to two main cataclastic zones of the Periadriatic Fault system mostly buried under quaternary loosen sediments. Thus, cataclastic zones represent preferential paths for Radon mobility and exhalation. The comparison of the IR distribution map, the geochemical composition of the main lithologies and the results from the in-situ measures, clearly indicate that, although outcropping lithologies represent an important factor contributing to the IR values, they cannot justify such high IR values measured in the buildings alone. Instead, the structural features of the Periadriatic Fault system play a key role in enhancing radon exhalation, exposing to potential radon risk specific areas within the territories of the municipalities located in the Pustertal/Pusteria Valley.
Keywords: Eastern Alps, Periadriatic Lineament, Radon, Indoor Radon, Natural Radioactivity
References:
Minach L., Verdi L., Marchesoni C., Amadori C. Radon in Sϋdtirol. Environmental Protection Agency. 1999.
Cinelli G., De Cort M. & Tollefsen, T. European Commission, Joint Research Centre. European Atlas of Natural Radiation. 2019. (Eds.), Publication Office of the European Union, ISBN 978-92-76-08259-0, doi:10.2760/520053.
How to cite: Benà, E., Ciotoli, G., Coletti, C., Galgaro, A., Massironi, M., Mazzoli, C., Morozzi, P., Ruggiero, L., Sciarra, A., Tositti, L., and Sassi, R.: Radon exhalation across the Periadriatic Lineament in the Pustertal/Pusteria Valley (Bolzano, North-Eastern Italy), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1274, https://doi.org/10.5194/egusphere-egu21-1274, 2021.
