Assessment of the natural radioactivity content in typical building materials employed in the Italian cultural heritage

Natural radionuclides from the uranium (238U) and thorium (232Th) families, as well as the radioactive isotope potassium, are present in varying concentrations in building materials and products obtained from rock and soil. In Italy, in historical monuments, natural building materials have been largely employed for decorative and structural purposes. In this study we measured the natural radioactivity content in six different materials (Grey tuff, basalt lava stone, lava stone, sand stone, magmatic rock and travertine). The activity concentrations were determined by high purity germanium (HPGe) detector based gamma spectrometry. The radium equivalent activity (Raeq), indoor absorbed gamma dose rate (Din), the annual effective dose (De), and the internal and external hazard indexes were evaluated to assess the radiation hazard for people living and working in buildings where these materials are used.