Occupational respiratory diseases
Louis-Philippe Boulet in Applied Respiratory Pathophysiology, 2017
We design by the name of “asbestosis” a group of complex hydrated silicates in a fibrous state. They include two main families: serpentine asbestosis and amphiboles [5]. Serpentine asbestosis—Chrysotile (white asbestosis): these long fibers are flexible, resistant to fire and have been used in the production of asbestosis textiles. This form of asbestosis was often found in mining industry in Quebec since 1878, where chrysotile constitutes more than 90% of industrial asbestosis.Amphiboles asbestosis: this group includes five varieties of rigid fibers that are easy to break but have an excellent resistance to acids. They include anthophyllite, amosite, crocidolite, actinolite, and tremolite.
Inorganic Particulates in Human Lung: Relationship to the Inflammatory Response
William S. Lynn in Inflammatory Cells and Lung Disease, 2019
The term asbestos encompasses a number of naturally occurring silicate mineral fibers in the serpentine and amphibole series.56 Chrysotile, the sole representative of the serpentine type of asbestos mineral, is a fibrous magnesium silicate consisting of a curled sheet which spirals around a central capillary. The fibers of chrysotile are typically curly or wavy (Figure 3A). The amphibole series has five recognized members: crocidolite (blue asbestos), amosite (brown asbestos), anthophyllite, tremolite, and actinolite. The amphibole minerals occur as double chains of linked silica tetrahedra which are crosslinked with various bridging cations, the identity of which is useful in the chemical identification of the various types of amphibole. For example, amosite contains iron (Fe+ +) as well as smaller amounts of magnesium and manganese, whereas crocidolite contains iron (Fe+ +, Fe + + +) and sodium as well as smaller amounts of magnesium. The amphiboles are typically straight fibers (Figure 3B). Asbestos may be associated with various contaminants, including trace metals such as nickel, chromium, cobalt, and aluminum, and various hydrocarbons (either as natural contaminants or as a result of processing and storage).56
Atmospheric particulates *
Bev-Lorraine True, Robert H. Dreisbach in Dreisbach’s HANDBOOK of POISONING, 2001
The word asbestos is used for any mineral that breaks down into fibers. The most commonly used form, chrysotile, is fibrous serpentine, a magnesium silicate containing 40% silica. Its fibers are tubular in section and range down to 0.015 μm in diameter, which is invisible in the ordinary microscope. Another form, crocidolite, is fibrous riebeckite, a sodium ferro-ferrisilicate containing 51% silica. Its fibers range down to 0.08 μm in diameter. Amosite is fibrous grunerite, a magnesium ferrosilicate containing 49% silica. Fibers of this form range down to 0.1 μm in diameter. Other forms include anthophyllite and tremolite-actinolite. Uses of the various forms of asbestos in cloth, brake linings, cement products, paper, flooring, gaskets, and paint amount to 3 million tons per year in the USA.
An updated evaluation of potential health hazards associated with exposures to asbestos-containing drywall accessory products
Published in Critical Reviews in Toxicology, 2019
Neva F. B. Jacobs, Kevin M. Towle, Brent L. Finley, Shannon H. Gaffney
The amphibole anthophyllite was reportedly measured in one study of drywall accessory products (Rohl et al. 1975); the anthophyllite mineral was presumably present as a trace contaminant of industrial talc. It is unclear whether this analysis actually identified asbestiform anthophyllite because the methods used did not permit distinction between asbestiform and non-asbestiform structures. To our knowledge, there are no published mesothelioma or lung cancer NOAEL values for asbestiform anthophyllite. However, numerous animal studies involving intrapleural injections of various asbestos fiber types have found that anthophyllite exhibited a lower potency for inducing mesothelioma than other amphiboles, and, in some studies, lower than even chrysotile (Wagner et al. 1973; Smith and Hubert 1974; Wagner et al. 1974; Wagner 1976; Pylev 1980). Hence, even if trace levels of asbestiform anthophyllite amphibole were truly present in some joint compound products, it is unlikely that these fibers pose a risk of asbestos-related disease.
Magnesium/silicon atomic weight percent ratio standards for the tissue identification of talc by scanning electron microscopy and energy dispersive X-ray analysis
Published in Ultrastructural Pathology, 2019
Sandra A. McDonald, Yuwei Fan, Rick A. Rogers, John J. Godleski
Regarding chemical variations, talc deposits in the earth may be accompanied by many other minerals, and this varies significantly by geography. Some of these include magnesite, MgCO3, and quartz, SiO.21 If present, the former would contribute magnesium atoms and not silicon, whereas the reverse is true for quartz. Also, there are minerals that, similar to talc, show EDS peaks for Mg and Si without other elements with atomic number >10, that need to be distinguished from talc. Morphology is key in this distinction, but the Mg/Si ratio also plays a key role. For example, chrysotile asbestos is a magnesium silicate but unlike talc, is virtually always fibrous (except in rare instances where small pieces of a fiber might dislodge and assume a non-fibrous particle appearance). The Mg/Si atomic weight % ratio for chrysotile is 1.29814, and this is very different from talc, falling far outside the ± 2σ range for the latter’s Mg/Si ratio. Anthophyllite, a noncommercial amphibole asbestos fiber type, normally has an iron peak along with Mg and Si, but its atomic structure may vary, and in a situation with low iron content, only Mg and Si peaks would show and the Mg/Si atomic weight % ratio would be 0.757. This is different from talc, and measurement of this ratio along with observation of fibrous structure would help with differentiation. Other asbestos subtypes have other cations with Mg and Si and so produce spectra that should not be confused with talc.
Empirical model of mesothelioma potency factors for different mineral fibers based on their chemical composition and dimensionality
Published in Inhalation Toxicology, 2019
Andrey Korchevskiy, James O. Rasmuson, Eric J. Rasmuson
The mesothelioma potency of anthophyllite is generally unknown and may depend on the morphology of the fibers in specific deposits. In the study of the Finland cohort of anthophyllite miners, four cases of malignant pleural mesothelioma were found among the cohort of 999 miners (Karjalainen et al. 1994). The Finnish authors stated that mesothelioma risk caused by anthophyllite was ‘higher than among chrysotile miners and almost as high as among amosite miners’ (Meurman et al. 1994). This statement is consistent with our modeling results. According to both of our models, Finnish anthophyllite seems to be 1.3 (Fe2O3 model) to 1.5 (total Fe model) times less potent than amosite, and respectively 62.5–66 times more potent than Quebec chrysotile.