Natural radioactivity and radon exhalation rate of Sardinian dimension stones

Abstract

Due to the ever-growing public concern about radon risk arising from building materials, the radon exhalation rates and the natural radioactivity of eighteen dimension stones mostly used in Sardinia and widely exported worldwide have been estimated by means of laboratory tests. Some of the quarrying companies that operate within the Sardinian territory provided the samples to be tested, which include twelve granitoids, four pyroclastic rocks and two basalts. The Activity Concentration Index (I ɤ ), the External Radiation Hazard Index (H ex ) and the Radium equivalent activity (Ra eq ) were calculated for each rock sample under investigation, based on the estimated values of 222 Rn exhalation rate and 226 Ra, 232 Th and 40 K radioactivity concentration. A poor correlation between radon release rates and 226 Ra radioactivity concentrations was found. The contribution to indoor radon accumulation was also simulated for the stone with the highest 222 Rn exhalation rate and the resulting concentration compared with the limit value establish by the 2013/59/Euratom Directive. These findings can be extended to rocks formed in similar geodynamic settings that are likely to produce igneous rocks with similar petrographic and geochemical features.

Natural radioactivity of rocks from the historic Jeroným Mine in the Czech Republic

“…However, the average 232 Th activity exceeded mean values of 18 Bq kg −1 reported for Ĉistá type granites (Krešl and Vaňková, 1978 (Anjos et al 2011;Chen and Lin 1996). Typical commercial granites from Greece and Sardinia gave respective 232 Th activity values of 77 and 66 Bq kg −1 (Papadopoulos et al 2012;Dentoni et al 2020). Commercial granites from Japan gave lower 232 Th activity values of 40 Bq kg −1 (Hassan et al 2010).…”

“…Four other granite samples exhibited relatively high 238 U activities of 215 Bq kg −1 for CH41, 153 Bq kg −1 for K9, 150 Bq kg −1 for K2 and 140 Bq kg −1 Fig. 9 (Dentoni et al 2020). Granites from Egypt and India gave the highest mean values of 118 and 119 Bq kg −1 (Harb et al 2012;Chen and Lin 1996).…”

Natural Radioactivity of Rocks from the Historic Jeroným Mine in the Czech Republic

“…2 and 10 show that the lowest 238 U activities observed come from samples collected from the northern part of the Jeroným Mine. (Dentoni et al, 2020). Granites from Egypt and India gave the highest mean values of 118 and 119 Bq kg -1 (Harb et al, 2012;Chen and Lin, 1996).…”

“…Brazilian, Indian and Swedish commercial granites gave respective average 232 Th activity values of 106, 172 and 110 Bq kg -1 (Anjos et al, 2011;Chen and Lin, 1996) . Typical commercial granites from Greece and Sardinia gave respective 232 Th activity values of 77 and 66 Bq kg -1 (Papadopoulos et al, 2012;Dentoni et al, 2020). Commercial granites from Japan gave lower 232 Th activity values of 40 Bq kg -1 (Hassan et al, 2010).…”

An Easily Integrable Industrial System for Gamma Spectroscopic Analysis and Traceability of Stones and Building Materials

“…Many approaches require destructive tests in which the sample is reduced to powder, dried, poured into a container with a specific geometry and sealed. After a period of about 1 month required for establishing the radioactive equilibrium between Ra and Rn (see Figure 2 of [ 7 ]), the sample is positioned inside a thick shielding structure used to reduce the external background and measured with High Purity Germanium (HPGe) [ 8 , 9 , 10 , 11 , 12 , 13 ] or with a higher efficiency NaI spectrometer [ 13 , 14 , 15 ]. The analysis to extract the radionuclide abundances and the ACIs are done offline and manually.…”