The role of Pusteria fault zone (North-Eastern Alps, Italy) on enhancing the Geogenic Radon component
Authors: Benà Eleonora , Ciotoli Giancarlo , Coletti Chiara , Galgaro Antonio , Mair Volkmar , Massironi Matteo , Mazzoli Claudio , Morelli Corrado , Morozzi Pietro , Ruggiero Livio , Tositti Laura , Sassi Raffaele 
Published: March 2022

&lt;p&gt;Radon (&lt;sup&gt;222&lt;/sup&gt;Rn) is a radioactive gas widely considered an indoor air pollutant due to its harmful effects on human health (WHO, 2009). The Geogenic Radon Potential (&lt;em&gt;GRP&lt;/em&gt;) quantifies what &amp;#8220;Earth delivers&amp;#8221; in terms of radon and represents the most important contributor to Indoor Radon Concentrations (&lt;em&gt;IRC&lt;/em&gt;) indicating the potential risk over an area (Bossew 2015). This is the special case of some municipalities in Pustertal/Pusteria Valley (Bozen/Bolzano, North-Eastern Italy) which display a high &lt;em&gt;IRC&lt;/em&gt;, based on Indoor measurements carried out by Minach et al. (1999), exceeding the threshold value recommended by EURATOM 59/2013. These municipalities are located along a wide brittle-fracture zone between the Pusteria Line (&lt;em&gt;PL&lt;/em&gt;, the eastern part of Periadriatic Lineament) and the Deffereggen-Anterselva-Valles (&lt;em&gt;DAV&lt;/em&gt;) faults. This fractured zone may act as preferential pathway for radon transport and migration by carrier gases (mainly CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt;), strongly contributing to its geogenic component. A &lt;em&gt;GRP&lt;/em&gt; map of the study area has been developed based on field measurements of radon, thoron (&lt;sup&gt;220&lt;/sup&gt;Rn) and other soil gases (CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;2&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;S) according to a sampling grid in an area of 6x10 km, and along three profiles crossing above mentioned fault lines in Terenten/Terento, M&amp;#252;hlen/Molini and Pfalzen/Falzes specific areas. The &lt;em&gt;GRP&lt;/em&gt; map was constructed by using soil gas radon data and other proxy variables in a spatial regression model. Soil gas measurements have been supported by high-resolution gamma-ray spectrometry on 16 rock samples belonging to the main outcropping lithologies in the study area &lt;em&gt;i.e.&lt;/em&gt; granite, orthogneiss, micaschist-paragneiss, phyllite. The preliminary radon map highlights a wide area of radon anomaly located to the North of the Periadriatic Lineament. The global trend of these radon anomalies follows the structural trend of the brittle fracture zone between &lt;em&gt;PL &lt;/em&gt;and &lt;em&gt;DAV&lt;/em&gt; faults and tends to close from the eastern part (Pfalzen/Falzes) toward the western part (Terenten/Terento) of the study area. In particular the easternmost sector of the map displays a wide north-south area of radon anomaly related to a wide brittle-fracture zone probably composed by a system of sub-parallel faults. The spatial distribution of radon anomalies confirms the key role played by the Pustertal/Pusteria fault system in the fluid degassing processes enhancing geogenic radon potential of the Pustertal/Pusteria Valley.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Keywords: Natural Radioactivity, Geogenic Radon Potential, Indoor Radon, Periadriatic Lineament&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;Bossew Peter.&amp;#160; Mapping the Geogenic Radon Potential and Estimation of Radon Prone Areas in Germany. Radiation Emergency Medicine 2015 Vol. 4, No.2 13-20.&lt;/p&gt;&lt;p&gt;Council Directive 2013/59/EURATOM. Basic safety standards for protection against the dangers arising from exposure to ionising radiation.&lt;/p&gt;&lt;p&gt;Minach L., Verdi L., Marchesoni C., Amadori C. Radon in S&amp;#252;dtirol. Environmental Protection Agency. 1999.&lt;/p&gt;&lt;p&gt;WHO 2009. Zeeb H. and Shannoun F. (eds.) WHO handbook in Indoor Radon - a public health perspective. ISBN 978 92 4 1547672.&lt;/p&gt;