Occurrence of natural asbestos in the historical quarries where “greenstones” are exploited: the example of the Gimigliano-Mount Reventino Unit ophiolite terranes (Calabria, Southern Italy)

In order to assess the occurrence of asbestiform minerals within the ophiolitic sequence of the Gimigliano-MountReventino Unit (Calabria, southern Italy), a detailed mineralogical and petrographic investigation by means of PolarizedLight Microscopy, X-ray powder diffractometry, Scanning Electron Microscopy combined with Energy-DispersiveSpectrometry, and Thermo Gravimetry together with Differential Scanning Calorimetry has been carried out.Indeed, the main lithotypes that constitute the ophiolite sequence (i.e. metabasites and serpentinites) are exploitedand marketed for building and ornamental purposes since prehistorical times (Punturo et al., 2004); for this reason,attention focused on the historical quarries with the main aim to detect the presence of asbestiform fibres which may beharmful for human health.Results showed that, among the asbestos minerals contained in metabasites, tremolite is the main constituentfollowed by actinolite; moreover, other fibrous amphiboles (not regulated by the Italian law) occurring are crossite,glaucophane, horneblende and gedrite. As far as serpentinites, chrysotile is the dominant asbestos phase (Bloise et al.,2014; Punturo et al., 2013).Obtained results hold environmental implications, since they can be used in order to take decisions for therealization of health protecting measures (e. g. during the road yards and quarry excavations) and may also provide datafor the compulsory Italian mapping of natural sites, since the selected sites are characterized by the presence of theasbestos commonly known as NOA (naturally occurring asbestos) as well as by the occurrence of other fibrous minerals(e.g., antigorite) that are non- asbestos classified and, therefore, not regulated by law (e.g. DM 18/03/2003).