Elisa Fornero

Asbestos health hazard: a spectroscopic study of synthetic geoinspired Fe-doped chrysotile.

The chrysotile fibres toxicity appears correlated to the redox activity of iron present in the chrysotile structure. In fact the generation of reactive oxygen species and other radicals appears catalyzed by iron ions and closely related to Fe ions organization in specific crystallographic sites having a capability to activate free radical generation. The Fe substitution to Mg and/or Si in the chrysotile structure appears important for asbestos health hazard investigation. Infrared and Raman spectroscopic analyses have been utilized to investigate Mg and/or Si ions replacement by Fe ions in chrysotile structure as a function of the Fe doping extent. Geoinspired synthetic chrysotile at different Fe doping extents has been obtained as unique phase by hydrothermal reaction in the presence or not of metallic Fe in the synthetic environment. The results highlight that Fe can replace both Mg and Si, differently modifying the chrysotile structure as a function of the Fe doping extent and the Fe doping process. The contemporary iron substitution into the octahedral and tetrahedral sheets reveals an appreciable increase of the dehydroxylation temperature which occurs at higher temperature than for iron-free sample. The results highlight the role of Fe substitution in the asbestos structure influencing the health hazard of biological systems.

Synthesis and characterization of tremolite asbestos fibres

Fibres of Fe-free tremolitic amphibole were synthesized using hydrothermal conditions. The run products contained only minor amounts of one other phase, quartz, as determined by X-ray powder diffraction (XRPD). The fibrous material was characterized by scanning and transmission electron microscopies combined with energy dispersive spectrometry (SEM-EDS and TEM-EDS), differential scanning calorimetry (DSC), thermogravimetry (TG) and micro-Raman spectroscopy. The average length and width of the fibres, as determined by SEM and TEM on about 600 fibrils, fall within the definition of breathable fibres and potentially carcinogenic. Electron diffraction patterns of selected areas (SAED) from single fibres revealed a high crystallinity. Raman spectroscopy showed bands matching those observed on natural samples of tremolite. These synthetic and well-characterized fibres can be used in in vitro studies, where cell reactions to synthetic and natural tremolite fibres are compared.

Environmental exposure to asbestos and other inorganic fibres using animal lung model.

Professional exposure to asbestos fibres is widely recognized as very dangerous to human health and for this reason many countries have banned their commercial uses. People, nevertheless, continue to be exposed to low dose of asbestos from natural and anthropogenic sources still in loco, for which the potential hazard is unknown. The aim of this research is to assess environmental exposure in an area with outcropping serpentinite rocks, which bear asbestos mineralizations, using sentinel animals which are a non-experimental animal model. We studied the burden of inorganic fibres in cattle lungs which come from two areas in Italys Western Alps bearing serpentinitic outcrops: Susa Valley with a heavy anthropization and Lanzo Valleys, with a minor human impact. The identification and quantification of inorganic fibres were performed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS). In comparison to humans, studies of animals have some advantages, such as no occupational exposure or history of smoking and, in the case of cattle, a sedentary life restricted to one region. Results spotlight that over than 35% of inorganic fibres found both in Susa and Lanzo valleys, belong to asbestos mineralogical species (asbestos tremolite/actinolite, chrysotile s.s., asbestos grunerite, crocidolite). We also observed a higher concentration of artificial fibrous products in Susa samples showing a correlation with the level of anthropization. These results confirm that sentinel animals are an excellent model to assess breathable environmental background because it is possible to eliminate some variables, such as unknown occupational exposure.

Study of inorganic particles, fibers, and asbestos bodies by variable pressure scanning electron microscopy with annexed energy dispersive spectroscopy and micro-Raman spectroscopy in thin sections of lung and pleural plaque.

In a previous work it has been demonstrated that micro-Raman spectroscopy is a technique able to recognize crystalline phases on untreated samples. In that case, inorganic particles and uncoated fibers from bronchoalveolar lavage (BAL) of a patient affected by pneumoconiosis were identified and characterized. In this work the technique is applied to asbestos bodies, that is, to coated fibers, and on crystallizations and fibrous phases observed in the plural plaque from patients affected by mesothelioma. From the Raman analysis the abundant fibrous material observed in the pleural area is talc, whereas rounded grains in the pleural tissue show the Raman spectrum of apatite, a calcium phosphate mineral particular to bones. In the pulmonary tissue many asbestos bodies, consisting of the incorporated fibers coated by iron-rich proteins, were observed. Under the 632.8 nm laser beam of the spectrometer, photo-crystallization of hematite in the iron-rich material forming the asbestos bodies can be proposed by the changes in the Raman spectra acquired during subsequent acquisitions. Nevertheless, the identification of the mineral phase constituting the incorporated fiber was possible by analyzing the Raman spectra; the results were confirmed by variable pressure scanning electron microscopy with annexed energy dispersive spectroscopy (VP-SEM-EDS) analyses.

Analysis of respired amphibole fibers (asbestos and non-asbestos classified): discrimination between natural and anthropogenic sources using sentinel animals

To evaluate the degree of exposure and to distinguish the contributions of respirable amphibole fibers (both asbestos and non-asbestos) from natural and anthropogenic sources, we investigated their burden in the lungs of sentinel animals. Lung samples of sentinel animals are more easily and continuously available in comparison to humans and are not affected by human variables such as occupational exposure and smoking habit. Fiber identification and quantification have been performed using a scanning electron microscope (SEM) with an energy-dispersive spectrometer (EDS). Results for detected amphibole fibers (both asbestos and non-asbestos) were obtained from six studied areas in Northwest Italy (Piedmont) and correlated to lithological and urbanization data. Detected amphibole fiber species have been classified as asbestos minerals occur naturally (NOA) or to anthropogenically sourced asbestos (ASA). This pilot study is a potentially useful tool for the evaluation of the distribution and sources of respirable inorganic fibers. The model should be applicable in any areas where lithological and anthropogenic characteristics are known.