Asbestos fibre identification vs. evaluation of asbestos hazard in ophiolitic rock mélanges, a case study from the Ligurian Alps (Italy)

Abstract

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

Coupling SEM-EDS and confocal Raman-in-SEM imaging: A new method for identification and 3D morphology of asbestos-like fibers in a mineral matrix

“…In the natural environment, a large set of metamorphic rocks may contain asbestos fibers, such as meta-ophiolitic rocks of basic or ultrabasic compositions (meta-gabbros, meta-basalts, serpentinites) (e.g. [4][5][6]) and hydrothermally altered dolerites ( [7]), more rarely in talc deposits ( [8]), metamorphosed dolostones and iron formations ( [9]) and subalkaline plutonic rocks ( [10]). Asbestos is listed as a Category 1 human carcinogen, because inhalation of asbestos fibers causes respiratory diseases, in particular asbestosis, lung cancers, and malignant mesothelioma (e.g.…”

Multi-Analytical Approach for Identifying Asbestos Minerals In Situ

“…In recent years several studies have focused on NOA with the aim of determining the potential health risks for neighboring populations [19][20][21][22][23]. This is due to the relatively widespread presence of NOA that are currently being excavated for numerous construction projects (railway lines, motorways etc.).…”

Naturally Occurring Asbestos (NOA) in Granitoid Rocks, A Case Study from Sardinia (Italy)

“…The occurrence in nature of fibrous amphiboles (anthophyllite, actinolite, tremolite, crocidolite and amosite), and chrysotile, i.e., the six silicate minerals defined by the existing regulation as "asbestos" (e.g., [1][2][3][4][5][6][7][8][9]) is increasingly attracting attention in environmental hazard evaluation [1,10]. In natural environments, the NOA (natural occurring asbestos) hazard arises when physical/mechanical processes produce airborne fibers that, due to their low density and small size, can be widely dispersed and, therefore, contaminate the atmosphere and water supplies e.g., [2,3] (Figure 1). Figure 1.…”