Chapter 5. Amphibole Asbestos Mineralogy

Zoltai, Tibor

doi:10.1515/9781501508219-009

Cited by 22 publications

(30 citation statements)

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“…Inset: SEM-energy dispersive spectroscopy spectrum of elemental composition of a typical Chai_08 fibre-like particle addition, biopersistence is affected by the ability of the particles to break longitudinally into fibrils. There is no evidence of fibril formation in the Chaitén ash, with fibre shape indicating transverse breakage giving brittle particles which are more easily cleared by macrophages (Zoltai 1981). No data exist on the toxicity of volcanic glass, feldspar or cristobalite fibres, so we cannot rule out that these fibres may be harmful, but the scarcity of the individual fibre-like particles means that they are unlikely to increase the potential respiratory hazard of the ash.…”

Section: Discussionmentioning

confidence: 95%

Cristobalite in a rhyolitic lava dome: evolution of ash hazard

et al. 2009

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Prolonged and heavy exposure to particles of respirable, crystalline silica-rich volcanic ash could potentially cause chronic, fibrotic disease, such as silicosis, in individuals living in areas of frequent ash fall. Here, we show that the rhyolitic ash erupted from Chaitén volcano, Chile, in its dome-forming phase, contains increased levels of the silica polymorph cristobalite, compared to its initial plinian eruption. Ash erupted during the initial, explosive phase (2-5 May 2008) contained approximately 2 wt.% cristobalite, whereas ash generated after dome growth began (from 21 May 2008) contains 13-19 wt.%. The work suggests that active obsidian domes crystallise substantial quantities of cristobalite on time-scales of days to months, probably through vapour-phase crystallisation on the walls of degassing pathways, rather than through spherulitic growth in glassy obsidian. The ash is finegrained (9.7-17.7 vol.% <4 µm in diameter, the respirable range) and the particles are mostly angular. Sparse, fibrelike particles were confirmed to be feldspar or glass.

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Section: Discussionmentioning

confidence: 95%

Cristobalite in a rhyolitic lava dome: evolution of ash hazard

et al. 2009

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“…Going hand-in-hand with trying to determine the morphology of amphiboles are explanations for the formation of asbestos and asbestiform amphiboles (Zoltai 1981). There seems to be a general agreement that stress fi elds are required to form asbestos.…”

Section: Morphology Mattersmentioning

confidence: 99%

Amphiboles: Environmental and Health Concerns

Gunter

Belluso

Mottana

2007

Reviews in Mineralogy and Geochemistry

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“…A full discussion of the mineralogy of asbestos is provided by Zoltai (1981) and Veblen and Wylie (1993). To avoid confusion, in this review the term "asbestos" is restricted to these minerals, reflecting its origins as a commercial term and its designation as such in regulatory policy.…”

Section: Asbestos Asbestiform Fibers and Empmentioning

confidence: 99%

“…Within the bundles, one crystallographic axis of the fibrils is parallel (parallel to length), but in the other crystallographic directions, the fibrils are not aligned and are readily separated (Alario Franco et al, 1977;Heinrich, 1965;Zoltai, 1977;Cressey et al, 1982). The high aspect ratio of these fine fibrils and fibril bundles enhances their flexibility and tensile strength (Hodgson, 1965;Zoltai, 1981). Minerals other than amphibole and chrysotile may occur in an asbestiform habit, such as talc, brucite, balangeroite, erionite, carlosturanite, and antigorite.…”

Section: Asbestos Asbestiform Fibers and Empmentioning

confidence: 99%

Methodologies for Determining the Sources, Characteristics, Distribution, and Abundance of Asbestiform and Nonasbestiform Amphibole and Serpentine in Ambient Air and Water

Wylie

Candela

2015

Journal of Toxicology and Environmental Health, Part B

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Anthropogenic and nonanthropogenic (erosion) processes contribute to the continuing presence of asbestos and nonasbestos elongated mineral particles (EMP) of amphibole and serpentine in air and water of urban, rural, and remote environments. The anthropogenic processes include disturbance and deterioration of asbestos-containing materials, mining of amphibole- and serpentine-bearing rock, and disturbance of soils containing amphibole and serpentine. Atmospheric dispersal processes can transport EMP on a global scale. There are many methods of establishing the abundance of EMP in air and water. EMP include cleavage fragments, fibers, asbestos, and other asbestiform minerals, and the methods employed do not critically distinguish among them. The results of most of the protocols are expressed in the common unit of fibers per square centimeter; however, seven different definitions for the term "fiber" are employed and the results are not comparable. The phase-contrast optical method used for occupational monitoring cannot identify particles being measured, and none of the methods distinguish amphibole asbestos from other EMP of amphibole. Measured ambient concentrations of airborne EMP are low, and variance may be high, even for similar environments, yielding data of questionable value for risk assessment. Calculations based on the abundance of amphibole-bearing rock and estimates of asbestos in the conterminous United States suggest that amphibole may be found in 6-10% of the land area; nonanthropogenic erosional processes might produce on the order of 400,000 tons or more of amphibole per year, and approximately 50 g asbestos/km(2)/yr; and the order of magnitude of the likelihood of encountering rock bearing any type of asbestos is approximately 0.0001.

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Chapter 5. Amphibole Asbestos Mineralogy

Cited by 22 publications

References 0 publications

Cristobalite in a rhyolitic lava dome: evolution of ash hazard

Cristobalite in a rhyolitic lava dome: evolution of ash hazard

Amphiboles: Environmental and Health Concerns

Methodologies for Determining the Sources, Characteristics, Distribution, and Abundance of Asbestiform and Nonasbestiform Amphibole and Serpentine in Ambient Air and Water

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