Environmental and Health : The Importance of Tremolite Occurence in the Pollino Geopark ( Southern Italy )

Worldwide studies have been done about the toxicity and carcinogenicity of asbestos minerals occurring in ophiolitic rocks. Inhalation of asbestos due to environmental exposure could cause malignant mesothelioma and lung cancers. In particular, the ophiolitic rocks in Tethyan realm represents a serious enivironmental concern due to both the presence of asbestos-like minerals and the large Cr abundance that is prone to solubilisation as CrVI. At the Pollino Geopark (southern Apennines, Italy), serpentinites-rich ophiolite rocks and sediments of the Frido Unit crop-out. In these rocks, tremolite, an asbestos-like mineral, is typically intergrown with fibrous antigorite and chrysotile. Tremolite shows acicular, friable, fibrous, and elongated habitus, can be easily released into the environment as a result of both natural processes and anthropogenic activities. In the analyzed rocks, tremolite is present mainly in veins as much as in the matrix and forms crowns around clinopyroxene porphyroclasts. The different analytical techniques showed the recognition of the amphibole-like minerals (actinolite and tremolite) that are the dominant phases, with a small percentage of Fe2+. The presence of Fe in the “ideal” tremolite asbestos could cause pathological effects for the human living in the Pollino Geopark. This study has several environmental relevant implications, including, for example, the realization of national health protecting programs and the mapping of natural sites characterized by the presence of asbestos minerals in Pollino Geopark and in others area where outcrop asbestos bearing ophiolitic rocks.


Introduction
This study concerns the investigation of asbestiform amphiboles coming from serpentinites of the Frido Unit (Pollino Geopark, southern Apennines).Serpentinites may contain amounts of asbestiform and other fibrous minerals, causing possible health problems due to fibre exposure [1].Major mineral element as Fe, and some trace metal elements may play a role in fibre toxicity [2].Furthermore, the weathering of outcrops of ultramafic rocks release chemical elements into groundwater, for example, the CrVI [3] where toxic elements may accumulate and result in human exposures.
The definition of asbestos used by regulatory agencies for identification includes the following six mineral species: chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophyllite [9,10].Among these minerals only chrysotile is a sheet silicate; the other minerals are included within the amphibole group.
The amphibole structure consists of two principal elements: a double chain of corner-sharing tetrahedral and a strip of edge-sharing octahedral, both of which extend in the c-direction.Six structural types of amphibole have been recognized [11].Their general chemical formula can be written as AB 2 C 5 T 8 O 22 W 2 where: A = vacant, Na, K, Ca, Li; B = Na, Li, Ca, Mn 2+ , Fe 2+ , Mg; C = Mg, Fe 2+ , Mn 2+ , Al, Fe 3+ , Mn 3+ , Ti 4+ , Li; T = Si, Al, Ti 4+ ; W = (OH), F, Cl, O 2− .Minor elements, such as Zn, Ni 2+ , Co 2+ , V 3+ , Sc, Cr 3+ , and Zr are also observed as C cations [2].The calculation of the crystal-chemical formula of the amphibole can be performed when assuming a content of 24 anions or 23 atoms per unit formula (apfu) [11].Tremolite is a monoclinic calcic amphibole with ideal formula Ca 2 Mg 5 Si 8 O 22 (OH) 2 that represents the Mg end member of the tremolite, actinolite, ferro-actinolite series (hereinafter actinolite series) consisting of clino-amphiboles common in greenschist to amphibolite facies ultrabasic rocks [12].The actinolite series is subdivided on the basis of ferro-actinolite content (calculated by the [(Fe + Mn)/(Fe + Mn + Mg) ratio] into tremolite (0-10% ferro-actinolite), actinolite (10-50% ferro-actinolite), and ferro-actinolite (50-100% ferro-actinolite), highlighting the common presence of crystals with intermediate compositions whose identification is difficult and is based only on their crystal chemistry [8].Crystal chemical characterization of fibrous amphibole is extremely relevant for environmental and health issues.In fact, the regulation applies only to fibres that fit the compositional definition of the actinolite series [13].This paper focuses on the identification and mineralogical investigation of tremolite fibres within serpentinite rocks.Results of a well-tested\multi-analytical approach, including X-ray powder diffraction analysis (XRPD), µ-Raman spectroscopy, Fourier Transform InfraRed Spectroscopy (FT-IR), Electron Microprobe Analysis (EMPA), and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), are presented and discussed in order to new data for the realization of health protecting measures, especially in people that are living in proximity of naturally occurring asbestos source and/or having a directly contact with asbestos during human activities, such as road construction and quarry excavations.Furthermore, these results may provide new information for the compulsory Italian mapping of natural sites that are characterized by the presence of the asbestos in its natural setting.

Environmental and Toxicological Relevance
It has been known since the early of XX century that chronic asbestos fiber inhalation may cause a slow and progressive diffuse interstitial pulmonary illness known with the term of "Asbestosis".In 1997, the International Expert Meeting on Asbestos, Asbestosis, and Cancer estimated that around 10,000 Malignant Mesothelioma and 20,000 lung cancer cases occur in specific area, as well as Western Europe, North America, Japan and Australia [14].
In the Pollino Geopark, many cases of mesothelioma were documented [15].The Regional Operating Centres of Basilicata (COR) along with the Italian National Mesothelioma Register (ReNaM) conducted in this area a wide-ranging epidemiological study whose results ascribed 17/90 mesothelioma cases to environmental factors, such as the exposure of people to naturally outcropping asbestos-bearing rocks [16].Asbesto minerals are constituted from flexible, heat-resistant, and chemically inert fibrous.When inhaled, they can cause neoplasms with a high mortality rate as asbestosis, lung cancer, and malignant mesothelioma [5][6][7][8].Asbestos fibers penetrate partially in the lung interstitial at respiratory and alveolar bronchial levels, causing alveolite phenomena with microemorrhages, small outbreaks of alveolar and interstitial edema.The pathognomonic histologic finds consist of asbestos corpuscles, interstitial or endoalveolar, consisting of asbestos fibers of 15-100 µm length, wrapped in a protein-containing mantle containing iron.On the pathogenic pathway, it is assumed that damage mechanisms follow this scheme: (a) chemical action of tissue fluid on asbestos fibers with release of silicic acid; (b) irritative-mechanical action; and, (c) formation of specific response antigens and formation of asbestos bodies [17].Among these, malignant pleural mesothelioma is an uncommon neoplasm typically originating by chrysotile, crocidolite, amosite, or tremolite that are considered to be the most dangerous carcinogen fibers, this is associated to inhalation of fluoro-edenite and erionite fibers [18].Furthermore, the presence in the fiber structure of cations such as Fe, Ni, and Ti, even in small amounts, may affect their physico-chemical properties [2, [19][20][21].In particular, the presence of Fe, the structural coordination, and furthermore, the Fe exposed on the fiber surface are important factors in the reactive oxygen species (ROS) production.According to in vitro studies on biological system-mineral interactions, the impurities and the size are considered to be responsible for the pathological effects [22][23][24][25].Toxicological studies on the interactions between bronchoalveolar fluids and inhaled atmospheric particulate [26,27] indicated that the metallic elements are released and accumulate in the human organs, producing different health effects [28].Furthermore, several researches have been demonstrated the strong linkage between mesothelioma and a series of environmental factors, such as the exposure to asbestos minerals, especially in people that are living in proximity of naturally occurring asbestos sources and/or having a direct contact with asbestos [18,[29][30][31].This is because asbestos-bearing rocks, chiefly serpentinites, can release significant amounts of fibres into the air, water, and soil, notably, both weathering processes and human activity (ore mining, grinding, and milling) can separate the fibres into smaller fibrils that are widely spread out into the environment, and are therefore easily inhalable.
Geosciences 2018, 8, x FOR PEER REVIEW 3 of 13 asbestos fibers with release of silicic acid; (b) irritative-mechanical action; and, (c) formation of specific response antigens and formation of asbestos bodies [17].Among these, malignant pleural mesothelioma is an uncommon neoplasm typically originating by chrysotile, crocidolite, amosite, or tremolite that are considered to be the most dangerous carcinogen fibers, this is associated to inhalation of fluoro-edenite and erionite fibers [18].Furthermore, the presence in the fiber structure of cations such as Fe, Ni, and Ti, even in small amounts, may affect their physico-chemical properties [2, [19][20][21].In particular, the presence of Fe, the structural coordination, and furthermore, the Fe exposed on the fiber surface are important factors in the reactive oxygen species (ROS) production.
According to in vitro studies on biological system-mineral interactions, the impurities and the size are considered to be responsible for the pathological effects [22][23][24][25].Toxicological studies on the interactions between bronchoalveolar fluids and inhaled atmospheric particulate [26,27] indicated that the metallic elements are released and accumulate in the human organs, producing different health effects [28].Furthermore, several researches have been demonstrated the strong linkage between mesothelioma and a series of environmental factors, such as the exposure to asbestos minerals, especially in people that are living in proximity of naturally occurring asbestos sources and/or having a direct contact with asbestos [18,[29][30][31].This is because asbestos-bearing rocks, chiefly serpentinites, can release significant amounts of fibres into the air, water, and soil, notably, both weathering processes and human activity (ore mining, grinding, and milling) can separate the fibres into smaller fibrils that are widely spread out into the environment, and are therefore easily inhalable.

Sampling
The Frido Unit serpentinites were collected at the Fosso Arcangelo site, which is located close to the San Severino Lucano village (Figure 1).As recently documented by [50] the serpentinite rocks can be classified as cataclastic and massive.Cataclastic serpentinites show high degree of fracturing and deformation that form cohesive serpentinites and/or fault breccias.The fractures are almost completely filled by exposed white and grey fibrous minerals [51].Two fiber types have been identified in the outcrops: (1) big and elongate fibers developed over slickensided surfaces; and, (2) very fine-grained fibers forming a network pervading the whole rock.Massive serpentinites show a low fracturing and deformation degree and any exposed fibrous minerals.Though the cataclastic and massive serpentinites have homogeneous mineral compositions [51].

X-Ray Powder Diffraction
All of the samples were powdered in a Retsch RS 100 planetary mill equipped with four agate jars and agate milling balls to generate a very fine powder suitable for mineralogical analysis, using a cooker hood 701 EXHAUST HEPA laminar flow capable to remove all the small and read fibres and protective clothing to prevent any contamination.The XRPD analyses were performed at the Department of Sciences, University of Basilicata, on randomly oriented powdered samples, using a Siemens D5000 powder diffractometer, CuKα radiation, 40 kV, and 32 mA.Data were recorded between 5 • and 70 • 2θ with step size of 0.02 • and scan speed of 2 s, in order to optimize the signal/noise ratio.The mineral identification was realized by mean of X'Pert HighScorePlus software (Panalytical, 2001) using the PDF-2 (2005) database.

µ-Raman Spectroscopy
The Raman spectroscopy measurements were performed on rock slabs obtained by a cutting machine hermetically sealed and waterjet to prevent the dispersion of fibres in the surrounding environment.The Raman analysis were carried out at the Department of Sciences, University of Basilicata, Potenza, using a Horiba Jobin-Yvon LabRam HR800 spectrometer equipped with a HeNe laser source with a wavelength of 633 nm, a CCD detector operating at −70 • C, and an edge filter that exclude from detection shift below 150 cm −1 .A spectral resolution of 4 cm −1 was obtained by a holographic grating with 600 lines/mm.Correct calibration of the instrument was verified checking the position of the Si band at ±520.7 cm −1 .Output laser power was 20 mV, and measurements were performed using optical microscope Olympus with objective of 10x, 50x and 100x.A laser beam spatial resolution of 1 µm was obtained with the 100x objective.Spectra result from the average of five acquisitions of 10 s to optimize the signal/noise ratio.Two regions of the Raman spectra were investigated: 1200-150 cm −1 for the characterization of structural bonding and 3800-3500 cm −1 for the identification of the hydroxyl groups.Amphibole minerals were identified on the basis of data reported in [52] and in the RUFF online free-database.

Electron Microprobe Analyses
Electron microprobe analyses were performed on the polished thin sections at the Department of Earth Sciences, University of Calabria (Arcavacata di Rende, Cosenza, Italy), using a JEOL JXA 8200 probe, equipped with five WDS spectrometers and an EDS spectrometer.The analytical conditions were excitation voltage 15 kV, specimen current 10 nA, beam diameter 1µm, count time (peak) 30 s, count time (background) 5 s.The following standards were used: Na, Al Si = Jadeite; Mg, Ca = Diopside; Fe, Cr, Mn = metal.

Scanning Electron Microscopy and Microanalysis EDS
SEM-EDS analyses were performed on the polished thin sections at the Department of Biology, Ecology, and Earth Sciences, University of Calabria (Arcavacata di Rende, Cosenza, Italy), using a FEI/Philips scanning microscope with GENESIS 4000 EDAX X-ray system based on a Si/Li crystal detector.Analytical conditions were 15 kV accelerating voltage and 600 pA beam current.

Fourier Transform InfraRed Spectroscopy
Fourier transform infrared spectroscopy measurements were carried out at the Department of Sciences, University of Basilicata.Samples were prepared by dispersing 1 mg of powdered rock into 450 mg of KBr.The homogenized mixture was subsequently pressed under vacuum to transparent pellets that are 13 mm in diameter.The FT-IR spectroscopy has been performed with a Jasco FT-IR 460 Plus interferometer.The spectra have been acquired by collecting 30 scans at 4 cm −1 resolution.Two regions of the Raman spectra were investigated: 2800-400 for structural bonding characterization and 3800-3500 cm −1 for the characterization of the hydroxyl groups.The spectra were displayed in the form of absorbance as a function of wavenumber and were evaluated using the program Origin.

Results and Discussion
Petrographic characterization shows that the serpentinites are pseudomorphic and vein textures [48].The serpentinites mainly consist of olivine, pyroxene (orthopyroxene and clinopyroxene), Cr-spinel, serpentine (lizardite, crysotile, antigorite, polygonal serpentine), clinochlore, magnetite, prehnite amphibole, and Fe-hydroxides (Table 1).The first texture is defined by serpentine group minerals [51] +magnetite mesh-texture with a core of relict olivine grains and by bastite pseudomorph after orthopyroxene.The second texture cross-cut the pseudomorphic texture [43,50].The veins are filled by serpentine and serpentine ± amphiboles, amphibole minerals (tremolite-actinolite series), calcite ± amphiboles [50], chlorite, and prehnite [48].The amphibole minerals, being of the tremolite-actinolite series [54], occurs as fine-fibers and are present in veins as much as in the matrix of analyzed rocks also forming crowns around clinopyroxene porphyroclasts.The X-ray diffraction analysis allowed for the recognition of the serpentine and amphibole-like minerals (actinolite, d = 8.31 Å; tremolite, d = 2.94 Å) that are the dominant phases, followed by 2:1 phyllosilicate (clinochlore, d = 4.74 Å), with minor amount of iron oxides (magnetite, d = 2.52 Å) (Figure 2).According with [50,52,54], our spectra, symmetric, and antisymmetric Si-O-Si stretching modes of fibrous amphibole give peaks at about 1062 and 675 cm −1 , the second one is also the strongest peak.O-H-O vibrations produce one other strong peaks at about 223 cm −1 (Figure 3a).In the OH vibrational region, amphibole shows two peaks, the most intense at 3675-3673 cm −1 (Mg; Mg; Mg), and the second at 3660-3663 cm −1 (Mg; Mg; Fe) obtained by Raman spectroscopy [54] (Figure 3b).Therefore, the number and relative intensity of these bands represent pure tremolite and almost pure tremolite (Fe-tremolite) with a small percentage of Fe 2+ (Figure 3b,c).According with [50,52,54], our spectra, symmetric, and antisymmetric Si-O-Si stretching modes of fibrous amphibole give peaks at about 1062 and 675 cm −1 , the second one is also the strongest peak.O-H-O vibrations produce one other strong peaks at about 223 cm −1 (Figure 3a).In the OH vibrational region, amphibole shows two peaks, the most intense at 3675-3673 cm −1 (Mg; Mg; Mg), and the second at 3660-3663 cm −1 (Mg; Mg; Fe) obtained by Raman spectroscopy [54] (Figure 3b).Therefore, the number and relative intensity of these bands represent pure tremolite and almost pure tremolite (Fe-tremolite) with a small percentage of Fe 2+ (Figure 3b,c).According with [50,52,54], our spectra, symmetric, and antisymmetric Si-O-Si stretching modes of fibrous amphibole give peaks at about 1062 and 675 cm −1 , the second one is also the strongest peak.O-H-O vibrations produce one other strong peaks at about 223 cm −1 (Figure 3a).In the OH vibrational region, amphibole shows two peaks, the most intense at 3675-3673 cm −1 (Mg; Mg; Mg), and the second at 3660-3663 cm −1 (Mg; Mg; Fe) obtained by Raman spectroscopy [54] (Figure 3b).Therefore, the number and relative intensity of these bands represent pure tremolite and almost pure tremolite (Fe-tremolite) with a small percentage of Fe 2+ (Figure 3b,c).In fact, as reported by [51,52], X value can be estimate from Raman spectra considering: X = (A 12 )/(1/3 + A 12 ), where A 12 is the ratio between the areas of OH Raman bands at about 3675 and 3660 cm −1 .In Figure 3b, is reported the composition (X value) estimated by using areas of the OH bands.The presence of Fe 2+ is confirmed by the FT-IR spectrum (Figure 4).
In fact, as reported by [51,52], X value can be estimate from Raman spectra considering: X = (A12)/(1/3 + A12), where A12 is the ratio between the areas of OH Raman bands at about 3675 and 3660 cm −1 .In Figure 3b, is reported the composition (X value) estimated by using areas of the OH bands.The presence of Fe 2+ is confirmed by the FT-IR spectrum (Figure 4).Site scattering at M(1), M(2) and M(3) sites indicates the presence of Mg and Fe 2+ as observed by [46] for the tremolite and ferro-actinolite and [55] for tremolite from the Susa Valley.In addition to the typical absorption band at 3675-3673 cm −1 assigned to the vibration of the O-H dipole that was bonded to three Mg cations and arrangement M(1) Mg M(1) Mg M(3 )Mg, which is a prominent band, is observed at 3660 cm −1 and a very weak band at 3647 cm −1 (Figure 4b), both of which were attributed to M(1)+M(3) Fe 2+ [45,56].Fe 3+ was allocated exclusively to M(2), owing to the absence of absorption bands at Δ = 50 cm −1 from the tremolite reference band in the FT-IR spectrum [55,57,58] possibly indicating the presence of M(1)+M(3) Fe 3+ .The EMPA on fibre bundles showed the chemical homogeneity of the fibres, with a mean composition of tremolite (Table 2, Figure 5).Site scattering at M(1), M(2) and M(3) sites indicates the presence of Mg and Fe 2+ as observed by [46] for the tremolite and ferro-actinolite and [55] for tremolite from the Susa Valley.In addition to the typical absorption band at 3675-3673 cm −1 assigned to the vibration of the O-H dipole that was bonded to three Mg cations and arrangement M(1) Mg M(1) Mg M(3 )Mg, which is a prominent band, is observed at 3660 cm −1 and a very weak band at 3647 cm −1 (Figure 4b), both of which were attributed to M(1)+M(3) Fe 2+ [45,56].Fe 3+ was allocated exclusively to M(2), owing to the absence of absorption bands at ∆ = 50 cm −1 from the tremolite reference band in the FT-IR spectrum [55,57,58] possibly indicating the presence of M(1)+M(3) Fe 3+ .The EMPA on fibre bundles showed the chemical homogeneity of the fibres, with a mean composition of tremolite (Table 2, Figure 5).This is confirmed by the absence of relevant peak broadening and/or asymmetry of the X-ray powder diffraction pattern (Figure 5).The analyses were normalized to 23 oxygens, and the cations were distributed according to the crystal-chemical formula AB2C5[T8O22/(OH)2] (A = vacant; B = Ca, Mg; C = Mg, Al; T = Al, Si).The EMPA results (Table 2) shows differences between MgO and CaO larger than their standard deviations and are related to the presence of calcite and serpentine, as previously revealed by the XRPD results.The FeOtot content varies from 2.47 to 5.06 wt % and is not related to the Ca content.This fact seems to indicate the absence of a Ca-Fe 2+ substitution scheme according to the results of [55].The EMP analyses revealed that the average composition that was obtained on single crystals is clearly distinguished from the typical compositions of the tremolite, in particular our samples show high content of Al2O3 (1.84-15.46wt %) and FeO (2.47-5.06wt %) with a small percentage of Cr2O3 (0.13-1.41 wt %), TiO2 (0.50-2.00), and Na2O (0.05-1.91) (Table 2).The scanning electron microscope equipped with electron-dispersive spectroscopy (SEM-EDS) shows that crystals are homogeneous, without zoning, although some crystals show variations compositions of SiO2, CaO, MgO, Fe2O3, Al2O3, and Na2O in the rim and core (Table 3).Finally, it is difficult to evaluate within serpentinites the amount of each fibrous phase by different analytical techniques used, since amphiboles with asbestiform habit are typically intergrown with serpentine minerals.

Conclusions
In this study, cataclastic asbestos-bearing serpentinites were studied by several analytical methods.The research focussed on serpentinite rocks that widely outcrop in the southern Apennine in natural outcrops, as well as in active and abandoned quarries, and result from serpentinization processes that have involved green-bluish mantle peridotites of Neotethys oceanic basin.Mineralogical results indicate the asbestiform tremolite and serpentine polimorphous [51], as the This is confirmed by the absence of relevant peak broadening and/or asymmetry of the X-ray powder diffraction pattern (Figure 5).The analyses were normalized to 23 oxygens, and the cations were distributed according to the crystal-chemical formula AB 2 C 5 [T 8 O 22 /(OH) 2 ] (A = vacant; B = Ca, Mg; C = Mg, Al; T = Al, Si).The EMPA results (Table 2) shows differences between MgO and CaO larger than their standard deviations and are related to the presence of calcite and serpentine, as previously revealed by the XRPD results.The FeO tot content varies from 2.47 to 5.06 wt % and is not related to the Ca content.This fact seems to indicate the absence of a Ca-Fe 2+ substitution scheme according to the results of [55].The EMP analyses revealed that the average composition that was obtained on single crystals is clearly distinguished from the typical compositions of the tremolite, in particular our samples show high content of Al 2 O 3 (1.84-15.46wt %) and FeO (2.47-5.06wt %) with a small percentage of Cr 2 O 3 (0.13-1.41 wt %), TiO 2 (0.50-2.00), and Na 2 O (0.05-1.91) (Table 2).The scanning electron microscope equipped with electron-dispersive spectroscopy (SEM-EDS) shows that crystals are homogeneous, without zoning, although some crystals show variations compositions of SiO 2 , CaO, MgO, Fe 2 O 3 , Al 2 O 3 , and Na 2 O in the rim and core (Table 3).Finally, it is difficult to evaluate within serpentinites the amount of each fibrous phase by different analytical techniques used, since amphiboles with asbestiform habit are typically intergrown with serpentine minerals.

Conclusions
In this study, cataclastic asbestos-bearing serpentinites were studied by several analytical methods.The research focussed on serpentinite rocks that widely outcrop in the southern Apennine in natural outcrops, as well as in active and abandoned quarries, and result from serpentinization processes that have involved green-bluish mantle peridotites of Neotethys oceanic basin.Mineralogical results indicate the asbestiform tremolite and serpentine polimorphous [51], as the main mineralogical components of serpentinites, followed by actinolite and other potentially harmful amphiboles that currently are not regulated by the Directive 2003/18/EC of the European Parliament and of the European Council of 27th March 2003.µ-Raman spectroscopy showed pure tremolite (Mg, Mg, Mg) and almost pure tremolite (Fe-tremolite) in the serpentinites.
Determined iron species are connected with the biological reactivity of the different fibre types [56,59,60].The "ideal" tremolite fibre is magnesium rich and free of iron [13], but small amounts of iron may substitute for magnesium in the crystalline structure of tremolite [10], in the octahedral site.Therefore, the crystal-chemical characterization of fibrous amphiboles is extremely relevant for environmental and health issues.In this study was reported the presence of FeO tot (2.47-5.06wt %) and Fe 2 O 3 (2.07-3.78wt %) in tremolite asbestos samples from Calabria-Lucanian boundary.The presence of Fe to ideal chemical composition tremolite asbestos, even in small amounts is considerable to be responsible for the pathological effects for the human living in this area.In fact, studies focusing on the interactions between broncho-alveolar fluids and inhaled atmospheric particulate [26,27], pointed out that, as a consequence of partial or total dissolution, metallic elements are released and accumulate in the human organs, inducing different health effects [28].Furthermore, the data on analyzed samples reveal that these fibres show a size that, according to several authors [61][62][63], may be significantly associated with carcinogenesis when breathed.It is important to point out that the size of the fibres may depend on excavation works or because they tend to split up along their elongation axis, and that fibres shorter than 1.5 µm could also be further associated with carcinogenic lung cancer [64,65].The mobilizable of Fe, for some authors [8,23], with the other factors as size, shape, etc., play a role in amphibole asbestos-induced toxicity.The mobilizable on the surface iron could be mainly responsible for amphibole asbestos-induced ROS toxicity [66,67].
Though the toxicity is related to the Fe content in the fibers, it is also necessary to emphatisize that the role played by trace metals including Mn, Cr, Co., Ni, Cu, Zn, since these elements may promote the lung cancer [2].
For this reason, serpentinites should be prudentially analyzed before their employment for building purposes assuming as crucial the geo-scientist role.
A further step could concern the concentration of trace elements in asbestos-like minerals occurring in ophiolitic rocks in the Pollino Massif.
Our findings thus improve the knowledge about the naturals sites, especially at the Calabria-Lucanian boundary, furnishing to the interested stakeholders a useful tool for planning best practices.
When considering the results that were obtained on the asbestos minerals occurring in ophiolitic rocks in the Pollino Geopark, the preparation of a GIS map in the area should be planned, also considering the incident mesothelioma cases, in order to obtain an accurate and complete lifetime residential and occupational histories.Works in progress would to develop a model to evaluate relationship between actual environmental exposure to NOA and major influencing factors, and to develop public health strategies to reduce exposure to asbestos from environmental sources.

Figure 1 .
Figure 1.Geological sketch map of the southern Apennines and location of the study area.

Figure 3 .
Figure 3. Raman spectra at low (a) and at high (b) wavenumbers of pure Mg-tremolite and Fetremolite from selected samples.μ-Raman Spectroscopy image of the fibrous tremolite (c) performed on rock slabs.

Figure 3 .
Figure 3. Raman spectra at low (a) and at high (b) wavenumbers of pure Mg-tremolite and Fetremolite from selected samples.μ-Raman Spectroscopy image of the fibrous tremolite (c) performed on rock slabs.

Figure 3 .
Figure 3. Raman spectra at low (a) and at high (b) wavenumbers of pure Mg-tremolite and Fe-tremolite from selected samples.µ-Raman Spectroscopy image of the fibrous tremolite (c) performed on rock slabs.

Figure 5 .
Figure 5. Secondary-electron image (SEI) of the fibrous tremolite and relative spectrum of the fibres.

Figure 5 .
Figure 5. Secondary-electron image (SEI) of the fibrous tremolite and relative spectrum of the fibres.

Table 2 .
Chemical composition obtained by electron microprobe analyses (30 analytical points) and min-max range of fibrous tremolite.

Table 2 .
Chemical composition obtained by electron microprobe analyses (30 analytical points) and min-max range of fibrous tremolite.

Table 3 .
Chemical composition obtained by SEM (15 analytical points) and variations compositions in the rim and core of fibrous tremolite.

Table 3 .
Chemical composition obtained by SEM (15 analytical points) and variations compositions in the rim and core of fibrous tremolite.