Comparative Analysis of Mineralogical Composition and Radioactivity Levels in Stone Samples from the Archaeological Site of Halaesa (Sicily, Italy)

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.