The generation of particulate matter emitted by management (e.g., mining, crushing, grinding, and milling) of ophiolite rock masses induces environmental impact due to production and dispersion of fibrous particles, which can be potentially classifiable as asbestos. Accordingly, characteristics of particles generated after mechanical stress on rocks are preparatory features to evaluate the environmental impact due to the asbestos hazard. This study deals with the characteristics (in terms of size, morphology and mineral classification) of particles generated after application of three different mechanical stress procedures (i.e. crushing, micronizing, and abrasion) on five ophiolite lithotypes and a man-made material obtained from rock mixing. A petrographic investigation has been addressed to classify the rock samples in terms of their internal fabric (foliated vs massive) and to individuate textural locus of fibrous minerals within the rock mass. The application of mechanical tests reveal that all the investigated lithotypes resulted able to spread out fibres as a consequence of rock disaggregation, with a prevalent amount of liberated fibres coming from samples characterised by pervasive foliation. The combined use of transmission electron microscopy and particle size analyser has been addressed to analyse morphological properties of the particulate matter. Different counting criteria have been used to distinguish asbestos fibres and non-asbestos particles (cleavage fragments). The results show that the counting criteria adopted for the fibre classification led to divergent interpretations in differentiating asbestos fibres and cleavage fragments and to determine the amount of asbestos. It derives the importance to define univocal criteria to define particle as asbestiform for supporting procedures and normatives addressed to evaluate the asbestos hazard in environmental sites.
Girolamo Belardi, G.V. (2018). Detecting asbestos fibres and cleavage fragments produced after mechanical tests on ophiolite rocks: clues for the asbestos hazard evaluation. JOURNAL OF MEDITERRANEAN EARTH SCIENCES, 10, 5-20.
Detecting asbestos fibres and cleavage fragments produced after mechanical tests on ophiolite rocks: clues for the asbestos hazard evaluation
Gianluca Vignaroli;
2018
Abstract
The generation of particulate matter emitted by management (e.g., mining, crushing, grinding, and milling) of ophiolite rock masses induces environmental impact due to production and dispersion of fibrous particles, which can be potentially classifiable as asbestos. Accordingly, characteristics of particles generated after mechanical stress on rocks are preparatory features to evaluate the environmental impact due to the asbestos hazard. This study deals with the characteristics (in terms of size, morphology and mineral classification) of particles generated after application of three different mechanical stress procedures (i.e. crushing, micronizing, and abrasion) on five ophiolite lithotypes and a man-made material obtained from rock mixing. A petrographic investigation has been addressed to classify the rock samples in terms of their internal fabric (foliated vs massive) and to individuate textural locus of fibrous minerals within the rock mass. The application of mechanical tests reveal that all the investigated lithotypes resulted able to spread out fibres as a consequence of rock disaggregation, with a prevalent amount of liberated fibres coming from samples characterised by pervasive foliation. The combined use of transmission electron microscopy and particle size analyser has been addressed to analyse morphological properties of the particulate matter. Different counting criteria have been used to distinguish asbestos fibres and non-asbestos particles (cleavage fragments). The results show that the counting criteria adopted for the fibre classification led to divergent interpretations in differentiating asbestos fibres and cleavage fragments and to determine the amount of asbestos. It derives the importance to define univocal criteria to define particle as asbestiform for supporting procedures and normatives addressed to evaluate the asbestos hazard in environmental sites.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
