μ-Raman spectroscopy and X-ray diffraction of asbestos’ minerals for geo-environmental monitoring: The case of the southern Apennines natural sources

Asbestos is a term commonly used to refer to those silicate minerals that show a typical fibrous habitus and crystallize as separable fibres. For the past decade, considerable research has focused on the strong correlation between deadly diseases and the exposure to asbestos-like minerals present in different environmental matrices. These harmful minerals generally occur as naturally exposed friable fibres that can be easily released into the environment as a result of both natural processes and anthropogenic activities. At the Calabria-Lucania boundary (southern Italy), the intense spreading of the asbestos fibres is also a consequence of the cataclastic features of the serpentinite outcropping. Therefore, it is necessary to intensify the geo-environmental monitoring in this area. The identification of asbestiform minerals in serpentinites is generally brought about by techniques requiring sample preparation such as: Scanning Electron Microscopy - Energy Dispersion Spectrometry, Transmission Electron Microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, polarized light optical microscopy, and differential thermal analyses. In this work, we evaluate the use of μ-Raman spectroscopy, on both low and high wavenumbers, in identifying the different serpentine and amphibole minerals. The comparison between the μ-Raman spectroscopy and X-ray powder diffraction is also discussed based on analytical procedures and results.