Assessment of the radon exhalation and the radiological risk due to natural radioactivity content in the “Pietra di Lecce” building material: A case study

The radon exhalation from the “Pietra di Lecce” (Lecce stone) building material, as well as its natural radioactivity content and thus the radiological health risk for humans, were assessed and reported as a case study in the present paper, to assess the risk of radioactivity associated with radiation exposure from the analyzed natural stone. In particular, the main methods applied were the Closed Chamber Method (CCM) with the Durridge Rad7 setup and the High Purity Germanium (HPGe) gamma spectrometry, to quantify the radon exhalation rate and the activity concentration of 226Ra, 232Th, and 40K, respectively. In addition, several indexes were calculated, i.e. the absorbed gamma dose rate (D), the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin), the radium equivalent activity (Raeq), the hazard indexes (Hex and Hin), the activity concentration index (I), and the alpha index (Iα). As main findings obtained results put into evidence low levels of radioactivity and, furthermore, all indexes were found to be lower than the threshold levels, therefore reasonably excluding radiological hazard effects for humans. Noteworthy, the study reported in this paper was developed in the framework of the PRIN 2022 PNRR ATHENA project, funded by the European Union - Next Generation EU.