In recent years, the high incidence of harmful health effects through inhalation of airborne asbestos from amphibole-bearing rock me´langes has been thoroughly documented. Here, we present a field-based, multi-scale\ud geological approach aimed at illustrating the occurrence of\ud amphibole fibrous mineralisation in an ophiolitic suite from\ud the Ligurian Alps (Italy) and discussing the implication on\ud in situ determination of the asbestos hazard. The rock\ud mélange is composed of plurimetre-sized blocks of different lithotypes (metagabbro, serpentinite, chloritoschist)\ud juxtaposed by the meaning of tectonic structures. The geological-structural survey revealed that the fibrous mineralisation is localised in specific structural sites of the rock volume, including veins and schistosity. Both microchemical and crystal structure analyses on selected fibrous samples revealed that actinolite fibres grow in veins within the metagabbro and in chloritoschists, while fibrous tremolite occurs in serpentinite schistosity. The morphological features of these amphibole fibres have been analysed in TEM images and used for classifying them as ‘‘asbestiform’’ or ‘‘non-asbestiform’’. The results show that the asbestos hazard determination is not unequivocally identified when different procedures for asbestos fibre identification and classification are applied. This may have impact on normatives and regulations in defining environmental hazards due to asbestos occurrence

No abstract

No abstract

No abstract

Key indicators: single-crystal X-ray study; T = 293 K; mean (S-O) = 0.003 Å; R factor = 0.034; wR factor = 0.080; data-to-parameter ratio = 29.4. inorganic compounds i164 # 2007 International Union of Crystallography