Research

24 pages, 9371 KiB

Open AccessArticle

Mineralogical Characterization and Dissolution Experiments in Gamble’s Solution of Tremolitic Amphibole from Passo di Caldenno (Sondrio, Italy)

by Ruggero Vigliaturo, Giancarlo Della Ventura, Jessica K. Choi, Alessandra Marengo, Federico Lucci, Michael J. O'Shea, Ileana Pérez-Rodríguez and Reto Gieré

Minerals 2018, 8(12), 557; https://doi.org/10.3390/min8120557 - 30 Nov 2018

Cited by 11 | Viewed by 4157

Abstract

In nature, asbestos is often associated with minerals and other non-asbestiform morphologies thought to be harmless, but not much is known about the potential toxic effects of these phases. Therefore, the characterization of natural assemblages should not be limited to asbestos fibers only. [...] Read more.

In nature, asbestos is often associated with minerals and other non-asbestiform morphologies thought to be harmless, but not much is known about the potential toxic effects of these phases. Therefore, the characterization of natural assemblages should not be limited to asbestos fibers only. This paper combines a multi-analytical characterization of asbestos from Valmalenco (Italy) with data from dissolution experiments conducted in a simulated interstitial lung fluid (Gamble’s solution), and a detailed dimensional study that compares the particle population before and after this interaction. The sample is identified as a tremolitic amphibole, exhibiting a predominance of fiber and prismatic habits at lower magnification, but a bladed habit at higher magnification. The results show that at different magnification, the dimensional and habit distributions are notably different. After the dissolution experiments, the sample showed rounded edges and pyramid-shaped dissolution pits. Chemical analyses suggested that a nearly stoichiometric logarithmic loss of Si and Mg occurred associated with a relatively intense release of Ca in the first 24 h, whereas Fe was probably redeposited on the fiber surfaces. A rearrangement of the more frequent habits and dimensions was recorded after the dissolution experiment, with a peculiar increase of the proportion of elongated mineral particles. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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23 pages, 15068 KiB

Open AccessArticle

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

by Federico Lucci, Giancarlo Della Ventura, Alessandra Conte, Manuela Nazzari and Piergiorgio Scarlato

Minerals 2018, 8(10), 442; https://doi.org/10.3390/min8100442 - 10 Oct 2018

Cited by 14 | Viewed by 5051

Abstract

All six minerals defined as “asbestos” by the existing regulation on asbestos hazard, i.e., actinolite, tremolite, anthophyllite, crocidolite and amosite amphiboles, and the serpentine-group mineral chrysotile are typical constituents of mafic and ultramafic magmatic rocks of ophiolitic sequences. However, little is known about [...] Read more.

All six minerals defined as “asbestos” by the existing regulation on asbestos hazard, i.e., actinolite, tremolite, anthophyllite, crocidolite and amosite amphiboles, and the serpentine-group mineral chrysotile are typical constituents of mafic and ultramafic magmatic rocks of ophiolitic sequences. However, little is known about the presence and distribution of naturally occurring asbestos (NOA) in plutonic felsic rocks. The Isadalu magmatic complex outcropping in central Sardinia and belonging to the post-variscan Permian volcanic cycle, is described here as an interesting occurrence of fibrous amphiboles in granitoid rocks. Field work and collected mineralogical/petrological data show that NOA fibers from the Isadalu complex belong compositionally to the actinolite-tremolite series. They were generated by metasomatic growth on pristine magmatic hornblende, at ca. 470 °C at 1 kbar, during sodic-calcic hydrothermal alteration. In terms of environmental hazard, the Isadalu complex represents a high-value case study, since the actinolite-bearing felsic rocks outcrop in a strongly anthropized area. Here, towns with local and regional strategic infrastructures (dams, pipes, hydroelectric power plants, water supply, roads) have been developed since the last century, also using the granitoid asbestos-rich stones. The aim of this study is to demonstrate that NOA and relative hazard are not univocally connected to a restricted typology of rocks. This result should be taken into account in any future work, procedure or regulation defining asbestos occurrences in natural environments. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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19 pages, 2825 KiB

Open AccessArticle

Infra Red Spectroscopy of the Regulated Asbestos Amphiboles

by Giancarlo Della Ventura, Ruggero Vigliaturo, Reto Gieré, Simone Pollastri, Alessandro F. Gualtieri and Gianluca Iezzi

Minerals 2018, 8(9), 413; https://doi.org/10.3390/min8090413 - 18 Sep 2018

Cited by 22 | Viewed by 6064

Abstract

Vibrational spectroscopies (Fourier Transform Infra Red, FTIR, and Raman) are exceptionally valuable tools for the identification and crystal–chemical study of fibrous minerals, and asbestos amphiboles in particular. Raman spectroscopy has been widely applied in toxicological studies and thus a large corpus of reference [...] Read more.

Vibrational spectroscopies (Fourier Transform Infra Red, FTIR, and Raman) are exceptionally valuable tools for the identification and crystal–chemical study of fibrous minerals, and asbestos amphiboles in particular. Raman spectroscopy has been widely applied in toxicological studies and thus a large corpus of reference data on regulated species is found in the literature. However, FTIR spectroscopy has been mostly used in crystal–chemical studies and very few data are found on asbestos amphiboles. This paper is intended to fill this gap. We report new FTIR data collected on a suite of well-characterized samples of the five regulated amphibole species: anthophyllite, amosite, and crocidolite, provided by the Union for International Cancer Control (UICC) Organization, and tremolite and actinolite, from two well-known occurrences. The data from these reference samples have been augmented by results from additional specimens to clarify some aspects of their spectroscopic features. We show that the FTIR spectra in both the OH-stretching region and in the lattice modes region can be effective for rapid identification of the asbestos type. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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11 pages, 5661 KiB

Open AccessArticle

Synchrotron Nano-Diffraction Study of Thermally Treated Asbestos Tremolite from Val d’Ala, Turin (Italy)

by Carlotta Giacobbe, Jonathan P. Wright, Dario Di Giuseppe, Alessandro Zoboli, Mauro Zapparoli and Alessandro F. Gualtieri

Minerals 2018, 8(8), 311; https://doi.org/10.3390/min8080311 - 24 Jul 2018

Cited by 6 | Viewed by 3083

Abstract

Nowadays, due to the adverse health effects associated with exposure to asbestos, its removal and thermal inertization has become one of the most promising ways for reducing waste risk management. Despite all the advances in structure analysis of fibers and characterization, some problems [...] Read more.

Nowadays, due to the adverse health effects associated with exposure to asbestos, its removal and thermal inertization has become one of the most promising ways for reducing waste risk management. Despite all the advances in structure analysis of fibers and characterization, some problems still remain that are very hard to solve. One challenge is the structure analysis of natural micro- and nano-crystalline samples, which do not form crystals large enough for single-crystal X-ray diffraction (SC-XRD), and their analysis is often hampered by reflection overlap and the coexistence of multiple fibres linked together. In this paper, we have used nano-focused synchrotron X-rays to refine the crystal structure of a micrometric tremolite fibres from Val d’Ala, Turin (Italy) after various heat treatment. The structure of the original fibre and after heating to 800 °C show minor differences, while the fibre that was heated at 1000 °C is recrystallized into pyroxene phases and cristobalite. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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13 pages, 3705 KiB

Open AccessArticle

The Effect of Grinding on Tremolite Asbestos and Anthophyllite Asbestos

by Andrea Bloise, Robert Kusiorowski and Alessandro F. Gualtieri

Minerals 2018, 8(7), 274; https://doi.org/10.3390/min8070274 - 28 Jun 2018

Cited by 16 | Viewed by 5659

Abstract

The six commercial asbestos minerals (chrysotile, fibrous actinolite, crocidolite, amosite, fibrous tremolite, and fibrous anthophyllite) are classified by the IARC as carcinogenic to humans. There are currently several lines of research dealing with the inertisation of asbestos minerals among which the dry grinding [...] Read more.

The six commercial asbestos minerals (chrysotile, fibrous actinolite, crocidolite, amosite, fibrous tremolite, and fibrous anthophyllite) are classified by the IARC as carcinogenic to humans. There are currently several lines of research dealing with the inertisation of asbestos minerals among which the dry grinding process has received considerable interest. The effects of dry grinding on tremolite asbestos and anthophyllite asbestos in eccentric vibration mills have not yet been investigated. Along the research line of the mechanical treatment of asbestos, the aim of this study was to evaluate the effects of dry grinding in eccentric vibration mills on the structure, temperature stability, and fibre dimensions of tremolite asbestos from Val d’Ala, (Italy) and UICC standard anthophyllite asbestos from Paakkila mine (Finland) by varying the grinding time (30 s, 5 min, and 10 min). After grinding for 30 s to 10 min, tremolite asbestos and anthophyllite asbestos showed a decrease in dehydroxylation and breakdown temperatures due to the increase in lattice strain and the decrease in crystallinity. Moreover, after grinding up to 10 min, tremolite and anthophyllite fibres were all below the limits defining a countable fibre according to WHO. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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12 pages, 1540 KiB

Open AccessArticle

Raman Micro-Spectroscopy Identifies Carbonaceous Particles Lying on the Surface of Crocidolite, Amosite, and Chrysotile Fibers

by Alessandro Croce, Aldo Arrais and Caterina Rinaudo

Minerals 2018, 8(6), 249; https://doi.org/10.3390/min8060249 - 13 Jun 2018

Cited by 13 | Viewed by 7419

Abstract

Micro-Raman spectroscopy has been applied on UICC (Union for International Cancer Control’s) crocidolite and amosite from South Africa and on UICC chrysotile from Canada. Under Optical Microscope (OM), the surface of the fibers was often characterized by areas, micrometric in size, appearing dark. [...] Read more.

Micro-Raman spectroscopy has been applied on UICC (Union for International Cancer Control’s) crocidolite and amosite from South Africa and on UICC chrysotile from Canada. Under Optical Microscope (OM), the surface of the fibers was often characterized by areas, micrometric in size, appearing dark. The laser beam was successively focused on areas of the same sample showing different optical contrasts. On the bright zones, Raman spectra peculiar for crocidolite, amosite or chrysotile were recorded. When dark areas were optically identified, the laser beam was addressed onto these regions and, in the Raman patterns, in addition to the bands produced by the mineral fiber, bands ascribing to substituted carbonaceous phases were observed. These bands were lying in the 4000–1100 cm⁻¹ spectral range. On the basis of the shape of the bands and their relative intensities, suggestions about the order-disorder of the carbonaceous particles could be proposed, and they appeared more ordered on amosite than on crocidolite and chrysotile. From the exposed data, crocidolite and amosite fibers from South Africa, and chrysotile fibers from Canada, largely used in industry in the past, are characterized by many carbonaceous micrometric particles, lying on the fiber surfaces. Based on the noxiousness of the carbon particles on human health, their presence on asbestos fibers may play a role in increasing the carcinogenic effects of the analyzed fibrous minerals. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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17 pages, 47132 KiB

Open AccessArticle

Effect of Grinding on Chrysotile, Amosite and Crocidolite and Implications for Thermal Treatment

by Andrea Bloise, Manuela Catalano and Alessandro Francesco Gualtieri

Minerals 2018, 8(4), 135; https://doi.org/10.3390/min8040135 - 28 Mar 2018

Cited by 24 | Viewed by 5768

Abstract

Nowadays, due to the adverse health effects associated with exposure to asbestos, its inertization is one of the most important issues of waste risk management. Based on the research line of mechano-chemical and thermal treatment of asbestos containing materials, the aim of this [...] Read more.

Nowadays, due to the adverse health effects associated with exposure to asbestos, its inertization is one of the most important issues of waste risk management. Based on the research line of mechano-chemical and thermal treatment of asbestos containing materials, the aim of this study was to examine the effects of dry grinding on the structure, temperature stability and fibre size of chrysotile from Balangero (Italy), as well as standard UICC (Union for International Cancer Control) amosite and standard UICC (Union for International Cancer Control) crocidolite. Dry grinding was accomplished in an eccentric vibration mill by varying the grinding time (30 s, 5 and 10 min). Results show a decrease in crystallinity, the formation of lattice defects and size reduction with progressive formation of agglomerates in the samples after the mechanical treatment. Transmission electron microscopy (TEM) results show that the final product obtained after 10 min of grinding is composed of non-crystalline particles and a minor residue of crystalline fibres that are not regulated because they do not meet the size criteria for a regulated fibre. Grinding results in a decrease of temperature and enthalpy of dehydroxylation (ΔH_dehy) of chrysotile, amosite and crocidolite. This permits us to completely destroy these fibres in thermal inertization processes using a lower net thermal energy than that used for the raw samples. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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16 pages, 1746 KiB

Open AccessArticle

Prismatic to Asbestiform Offretite from Northern Italy: Occurrence, Morphology and Crystal-Chemistry of a New Potentially Hazardous Zeolite

by Michele Mattioli, Matteo Giordani, Pierluca Arcangeli, Laura Valentini, Matteo Boscardin, Alessandro Pacella and Paolo Ballirano

Minerals 2018, 8(2), 69; https://doi.org/10.3390/min8020069 - 14 Feb 2018

Cited by 17 | Viewed by 4357

Abstract

A multi-methodological approach, based upon field investigation, morphological characterization, chemical analysis and structure refinement was applied to different samples of fibrous offretite, a new potentially hazardous zeolite recently discovered in northern Italy. Their morphology ranges from stocky-prismatic to asbestiform. All the investigated fibers [...] Read more.

A multi-methodological approach, based upon field investigation, morphological characterization, chemical analysis and structure refinement was applied to different samples of fibrous offretite, a new potentially hazardous zeolite recently discovered in northern Italy. Their morphology ranges from stocky-prismatic to asbestiform. All the investigated fibers may be considered as “inhalable”, and they are well within the range of the “more carcinogenic fibers” regarding diameter. As regards the length, the main mode observed in the asbestiform samples is 20–25 μm, and ~93% of the measured fibers are >5 μm and may be significantly associated with carcinogenesis also in terms of lengths. The chemical-structural features of the investigated fibers are comparable: the extra-framework cations K⁺, Mg²⁺ and Ca²⁺ are present in all samples in similar proportions, and refined cell parameters are similar among the samples. Offretite occurs in 60% of the investigated sites, with an estimated amount up to 75 vol % of the associated minerals. The presence of this mineral could be of concern for risk to human health, especially if one considers the vast number of quarries and mining-related activities that are operating in the zeolite host rocks. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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16 pages, 1820 KiB

Open AccessArticle

Different Erionite Species Bind Iron into the Structure: A Potential Explanation for Fibrous Erionite Toxicity

by Alessandro Pacella, Carlo Cremisini, Elisa Nardi, Maria Rita Montereali, Ida Pettiti, Matteo Giordani, Michele Mattioli and Paolo Ballirano

Minerals 2018, 8(2), 36; https://doi.org/10.3390/min8020036 - 23 Jan 2018

Cited by 18 | Viewed by 3766

Abstract

In this investigation, the crystal chemical characterization of one sample of woolly erionite-K (Lander County, NV, USA) was examined after suspension in a FeCl₂ solution, in anaerobic conditions. The aim of this study was to determine the effect of the chemical composition [...] Read more.

In this investigation, the crystal chemical characterization of one sample of woolly erionite-K (Lander County, NV, USA) was examined after suspension in a FeCl₂ solution, in anaerobic conditions. The aim of this study was to determine the effect of the chemical composition of erionite on its efficiency to bind iron. Inductively coupled plasma (ICP) results showed that the sample bound Fe(II) through an ion-exchange mechanism mainly involving Ca. In addition, chemical and structural data indicated that Fe(II) is fixed at the Ca3 site, six-fold coordinated to water molecules. According to Brunauer–Emmett–Teller (BET) sample surface area the amount of Fe(II) bound by the fibers was comparable with that retrieved for fibrous erionite-Na sample from Rome (OR, USA) for which the ion-exchange process mainly affected Na. This finding provides clear evidence of a strong tendency of Fe(II) to bind to the erionite structure. Furthermore, considering that the woolly erionite-K from Langer County differs markedly from erionite-Na from Rome in the extra-framework cation content, our observations indicate that the Fe binding efficiency is not significantly modulated by the chemical composition. Notably, Fe ion-exchanged and/or accumulated on the fiber surface can generate hydroxyl radicals via the Fenton reaction, thus influencing the potential carcinogenicity of the different erionite species. Full article

(This article belongs to the Special Issue Occurrence, Crystal-Chemistry and Properties of Fibrous Minerals)

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