In this paper, an assessment of the natural radioactivity level, radon exhalation, metal contamination, and mineralogy of a granodiorite rock sample from Stilo, in the Calabria region, Southern Italy is presented as a case study. This rock was employed as a building material in the area under study. The specific activity of ²²⁶Ra, ²³²Th and ⁴⁰K natural radioisotopes was assessed through high-purity germanium (HPGe) gamma-ray spectrometry. Then, several indices such as the absorbed gamma dose rate (D), the annual effective dose equivalent (AEDE), the activity concentration index (ACI) and the alpha index (I_α), were quantified to determine any potential radiological health risk related to radiation exposure from the analyzed rock. Furthermore, E-PERM electret ion chambers and inductively coupled plasma mass spectrometry (ICP-MS) measurements were carried out to properly quantify the radon exhalation rate and any possible metal pollution, respectively. In particular, to further address metal pollution factors, the geo-accumulation index (I_geo) was calculated to properly address the toxicity levels of the ecosystem originating from the detected metals. Finally, with the aim of successfully discriminating the provenance of such naturally occurring radionuclides, a combined approach involving X-ray diffraction (XRD) and µ-Raman spectroscopy was employed for the identification of the main radioisotope-bearing minerals characterizing the investigated granodiorite. The results achieved in this case study can be taken as the basis for further inquiries into background levels of radioactivity and chemical contamination in natural stone employed as building materials.

This work reports the findings of an investigation aimed at assessing, for the first time, the natural and anthropogenic radioactivity content of marine sediments collected from selected areas of Sicily, Southern Italy. In particular, it focused on evaluating the average activity concentration of detected radionuclides and the radiological hazard for humans, above all considering the use of this material for nourishing actual eroded beaches. To this aim, the quantification of the average specific activity of ²²⁶Ra, ²³²Th, and ⁴⁰K natural and ¹³⁷Cs anthropogenic radioisotopes was addressed through the employment of High-Purity Germanium (HPGe) gamma-ray spectrometry. Furthermore, the absorbed gamma dose rate (D), the annual effective dose equivalent outdoor (AEDE_out), the external hazard index (H_ex), and the excess lifetime cancer risk (ELCR) were also calculated to evaluate the radiological hazard for humans related to external exposure to ionizing radiations. Furthermore, the average specific activity of ¹³⁷Cs was found to be less than the lowest detectable activity in all cases, excluding anthropogenic radioactive contamination of the investigated samples. Finally, Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA), i.e., multivariate statistics, were carried out by analyzing detected radioactivity and radiological characteristics to evaluate their relationship with the sampling locations.

This work presents the results of a multi-technique comparative investigation aimed at assessing the mineralogical composition and radioactivity levels of two stone fragments from different areas of the archaeological site of Halaesa (Sicily, Italy). The analysis employed an integrated approach combining μ-energy-dispersive X-ray fluorescence (μ-EDXRF) spectroscopy, µ-Raman spectroscopy, X-Ray Diffraction (XRD), ion chromatography (IC), High-Purity Germanium (HPGe) gamma spectrometry, and E-PERM electret ion chamber methods. By examining the stone composition at both the elemental and molecular scales, with support from ion chromatography data, potential degradation patterns linked to post-depositional weathering and external decay agents were identified. Moreover, the specific activity of radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) and the ²²²Rn exhalation rates were measured, enabling the estimation of a set of radiological indices that assess potential health hazards associated with prolonged exposure to these lithic materials. The findings highlight how a multidisciplinary approach can foster the assessment of stone deterioration mechanisms, supporting the design of optimized conservation strategies aimed at preserving the archaeological heritage of Halaesa and ensuring the safety of both the public and onsite personnel.