Damage of calcarenite stone in archaeological site: relationship between wheathering, pollution and biological agents

For thousand of years, when magnificence and beauty were the goals of architecture, stones were the most widely used durable materials. The deterioration of building stones causes irreparable damages to our cultural heritage, not only as loss of architecture and ancient art, but especially as loss of symbols of human cultural identity and continuity. Sun, frost, wind, rain, pollution etc. contribute to a gradual process of weathering. Biological activity also plays a role and its association with physico-chemical phenomena should be considered essential for understanding long term deterioration. In this contest appear necessary to understand the weight of each single environmental parameter in order to assess and to plan not only a suitable restoration project and a preventive maintenance but also to test natural products (specific biocides) to be used to limit the degradation caused by bio deterioration agents We studied the influence and synergistic effects of climatic parameters (temperature, light irradiation, wind intensity, humidity), pollution (SO2, CO, NO2, Ozone and heavy metals), and biological attacks on a building placed between an archaeological site of Lavello, a little town located in the Basilicata Region, and the industrial area surrounding this town. Moreover, X-ray diffraction, X-ray induced photoelectron spectroscopy (XPS), X-ray fluorescence spectrometry (XRF), ground penetrating radar and geo-electrical measurements (GPR and MGE), Fourier Transform Infrared spectroscopy (FT-IR) and biological investigations were carried out on powdered calcarenite and on stones samples. Preliminary results show that climatic parameters and pollution undermine the structure and the compactness of stones (i.e. micro-fractures, increase of salts’ concentration) favouring the biological colonization (bacteria, mushrooms and lichens) especially in south–east direction of prevailing winds.