Asbestos Deposits Research Articles

Anthophyllite Asbestos: The Role of Fiber Width in Mesothelioma Induction Part 1: Epidemiological Studies of Finnish Anthophyllite Asbestos

Anthophyllite asbestos only occurs in a few parts of the world in sufficient quantities to be mined. The largest deposits of anthophyllite asbestos occur in Finland where it was mined for more than 75 years and very extensively used and distributed, anciently, for more than six millennia. Anthophyllite is one of the five minerals known collectively as amphibole asbestos. Studies of the effect of these five mineral fibre types when inhaled have shown that fibre width is an important determinant of mesothelioma induction. Only the “thinner” fibres or those with fiber diameter dimensional profiles predominantly less than 0.25 – 0.30 µm, are clearly mesotheliogenic. The “thicker” ones or those whose predominant widths are greater than these diameters do not appear to show an observable attendant risk of mesothelioma. Observations based on studies of at least, two “thick” forms of amphibole asbestos support these hypotheses. The one is Bolivian crocidolite; the other Finnish anthophyllite. The Finnish anthophyllite industry presents an important opportunity to study the robustness of the theory that fibre width is key to mesothelioma genesis as vast numbers of people in all sectors of the Finnish industry and their families have historically incurred massive fiber exposures sufficient to cause a gross excess of asbestosis. Nonetheless, in spite of these long term, high dose exposures clear evidence for a mesothelioma risk due to anthophyllite asbestos is still lacking.

Mesothelioma: recent highlights.

Recent discoveries have elucidated some of the mechanisms responsible for the development of mesothelioma. These discoveries are: (I) the critical role of chronic inflammation in promoting mesothelioma growth, driven by the release of high mobility group box protein-1 (HMGB1) following asbestos deposition in tissues and its potential role as a biomarker to identify asbestos exposed individuals and mesothelioma patients; (II) the discovery that inherited heterozygous germline mutations of the deubiquitylase BRCA-associated protein 1 (BAP1) cause a high incidence of mesothelioma in some families; and that (III) germline BAP1 mutations lower the threshold of asbestos required to cause mesothelioma in mice, evidence of gene X environment interaction. These findings together with the identification of novel serum biomarkers, including HMGB1, Fibulin-3, etc., promise to revolutionize screening and treatment of this malignancy in the coming years.

Tatarinovite Са3Al(SO4)[В(ОH)4](ОH)6 · 12H2O, a new ettringite-group mineral from the Bazhenovskoe deposit, Middle Urals, Russia, and its crystal structure

A new mineral, tatarinovite, ideally Са3Аl(SO4)[В(ОН)4](ОН)6 · 12Н2O, has been found in cavities of rhodingites at the Bazhenovskoe chrysotile asbestos deposit, Middle Urals, Russia. It occurs (1) colorless, with vitreous luster, bipyramidal crystals up to 1 mm across in cavities within massive diopside, in association with xonotlite, clinochlore, pectolite and calcite, and (2) as white granular aggregates up to 5 mm in size on grossular with pectolite, diopside, calcite, and xonotlite. The Mohs hardness is 3; perfect cleavage on (100) is observed. D meas = 1.79(1), D calc = 1.777 g/cm3. Tatarinovite is optically uniaxial (+), ω = 1.475(2), e = 1.496(2). The IR spectrum contains characteristic bands of SO4 2−, CO3 2−, B(OH)4 −, B(OH)3, Al(OH)6 3-, Si(OH)6 2-, OH–, and H2O. The chemical composition of tatarinovite (wt %; ICP-AES; H2O was determined by the Alimarin method; CO2 was determined by selective sorption on askarite) is as follows: 27.40 CaO, 4.06 B2O3, 6.34 A12O3, 0.03 Fe2O3, 2.43 SiO2, 8.48 SO3, 4.2 CO2, 46.1 H2O, total is 99.04. The empirical formula (calculated on the basis of 3Ca apfu) is H31.41Ca3.00(Al0.76Si0.25)Σ1.01 · (B0.72S0.65C0.59)Σ1.96O24.55. Tatarinovite is hexagonal, space gr. P63, a = 11.1110(4) A, c = 10.6294(6) A, V = 1136.44(9) A3, Z = 2. Its crystal chemical formula is Са3(Аl0.70Si0.30) · {[SO4]0.34[В(ОН)4]0.33[СO3]0.24}{[SO4]0.30[В(ОН)4]0.34[СО3]0.30[В(ОН)3]0.06}(ОН5·73О0.27) · 12Н2O. The strongest reflections of the powder X-ray diffraction pattern [d, A (I, %) (hkl)] are 9.63 (100) (100), 5.556 (30) (110), 4.654 (14) (102), 3.841 (21) (112), 3.441 (12) (211), 2.746 (10) (302), 2.538 (12) (213). Tatarinovite was named in memory of the Russian geologist and petrologist Pavel Mikhailovich Tatarinov (1895–1976), a well-known specialist in chrysotile asbestos deposits. Type specimens have been deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow.

Identification of Chrysotile in Local Soil at Beypinari Village (Sivas-Turkey) Regarding Mine and Health Issue

Abstract Asbestos is dangerous for health and is forbidden to use in Turkey, but villagers who live in rural eastern part still use it especially for their home for insulation purposes and even as a substitute for baby powder. Therefore, geological and chemical properties of this type of soil, which is near the settlement, should be characterized and identified from the point of view of health. Beypinari asbestos deposits are located at Beypinari village, about 90 km southeast of Sivas, Turkey within Central Anatolian Ophiolites. Therefore, in the present study, the existence of chrysotile in Beypinari asbestos deposit were characterized and identified by mineralogical analysis and by major, trace, REE analysis. The results show that the samples contain different amount of calcite mineral, the main mineral being chrysotile.

Current Research and Opportunities to Address Environmental Asbestos Exposures.

SummaryAsbestos-related diseases continue to result in approximately 120,000 deaths every year in the United States and worldwide. Although extensive research has been conducted on health effects of occupational exposures to asbestos, many issues related to environmental asbestos exposures remain unresolved. For example, environmental asbestos exposures associated with a former mine in Libby, Montana, have resulted in high rates of nonoccupational asbestos-related disease. Additionally, other areas with naturally occurring asbestos deposits near communities in the United States and overseas are undergoing investigations to assess exposures and potential health risks. Some of the latest public health, epidemiological, and basic research findings were presented at a workshop on asbestos at the 2014 annual meeting of the Society of Toxicology in Phoenix, Arizona. The following focus areas were discussed: a) mechanisms resulting in fibrosis and/or tumor development; b) relative toxicity of different forms of asbestos and other hazardous elongated mineral particles (EMPs); c) proper dose metrics (e.g., mass, fiber number, or surface area of fibers) when interpreting asbestos toxicity; d) asbestos exposure to susceptible populations; and e) using toxicological findings for risk assessment and remediation efforts. The workshop also featured asbestos research supported by the National Institute of Environmental Health Sciences, the Agency for Toxic Substances and Disease Registry, and the U.S. Environmental Protection Agency. Better protection of individuals from asbestos-related health effects will require stimulation of new multidisciplinary research to further our understanding of what constitutes hazardous exposures and risk factors associated with toxicity of asbestos and other hazardous EMPs (e.g., nanomaterials).

Le développement minier au Nunavik et l’importance du parc national des Pingualuit pour protéger l’environnement et la culture inuit

Depuis la fin des années 1950, de nombreuses compagnies minières ont exploré la Fosse de l’Ungava au Nunavik (Canada). Des gisements de nickel, de cuivre et d’amiante y ont été exploités, ou sont en ce moment exploités, depuis les années 1970. Actuellement les compagnies Canadian Royalties et Glencore Xstrata emploient quelque 1500 personnes sur leurs sites d’extraction. Les Kangirsujuamiut, Sallumiut, Puvirnitumiut et les Nunavimmiut en général ont dû apprendre à vivre avec les retombées socioéconomiques et environnementales des projets miniers. Si leur perception de l’activité minière au Nunavik a évolué avec le temps, l’importance qu’ils accordent à la protection de l’environnement, elle, ne s’est pas érodée. Des comités comme la Commission de la qualité de l’environnement Kativik, le Comité Raglan et le Comité Nunavik Nickel voient à ce que le Nunavik continue à être perçu comme un territoire sain où il est toujours possible de pratiquer des activités de subsistance. La création du parc national des Pingualuit à proximité des mines aide également à minimiser les impacts environnementaux négatifs et offre aux Nunavimmiut la possibilité de récupérer un territoire qui avait été délaissé avec le temps. Le parc national des Pingualuit permet aux jeunes générations de se réapproprier une partie de leur culture, simplement en occupant le territoire.

More than 97% of Human Papilloma Virus Type 16 (HPV-16) was Found with Chrysotile Asbestos & Relatively Smooth Round Tumor Outline, and Less than 3% was found with HPV-18 and Tremolite Asbestos & Irregular Sawtooth-like Zigzag Outline in Breast Cancer Tissues in Over 500 Mammograms of Female Patients: Their Implications in Diagnosis, Treatment, and Prevention of Breast Cancer

In the past, Human Papillomavirus Type 16 (HPV-16) was considered to be the main cause of cancer in the oropharynx and genital organs. Cervical cancer of the uterus is the most well-known cancer associated with HPV-16. Among the oncogenic HPVs, types 16 and 18 are most responsible for the majority of the HPV-caused cancers. Recently, using EMF Resonance Phenomenon between 2 identical substances, we non-invasively measured HPV-16 and HPV-18 among 25 physicians and 25 dentists and found that all 50 have HPV-16 in oral cavities and oropharynx but not HPV-18. However most dentists have a stronger infection than physicians. Among them were 2 female dentists with breast cancer containing HPV-16 and strong infections of HPV-16 in the oral cavities and oropharynx. When the author checked their breast cancer positive areas as well as the mammograms of cancer positive areas, Chrysotile Asbestos co-existed with an infection of HPV-16. We then examined over 500 published mammograms of women with malignant breast cancer published by other institutes, and we found HPV-16 in more than 97% and HPV-18 in less than 3% of the breast cancer mammograms examined. Less than 0.4% of cases were found as a variety of combination of HPV-16 & HPV-18. We also discovered that breast cancer with HPV-16 always co-exists with increased Chrysotile Asbestos deposits, and the outline of the breast cancer positive area is a relatively smooth and round or oval shape, and breast cancer with HPV-18 always co-exists with increased Tremolite Asbestos, where the tumor outline is an irregular saw-tooth like zigzag pattern. Based on these findings, better methods of diagnosis, treatment and prevention with a vaccine can be developed.

Neoproterozoic Cana Brava chrysotile deposit (Goiás, Brazil): Geology and geochemistry of chrysotile vein formation

The Cana Brava chrysotile asbestos deposit of Goiás, Brazil, contains approximately 150Mt of ore with an average of 3.5wt.% of cross-fiber chrysotile and lies in the differentiated, mafic–ultramafic Neoproterozoic Cana Brava complex. This complex was formed at approximately 0.79Ga and metamorphosed at 0.77 to 0.76 and 0.63Ga. The 0.77 to 0.76Ga metamorphic event was a high-grade one that transformed the mafic and ultramafic rocks into meta-peridotites and meta-pyroxenites. The low-grade 0.63Ga metamorphism allowed the formation of black, red and brown serpentinite, graphitic, magnesite-rich talc serpentinite, and rodingite, which became folded and foliated. At the end of the 0.63Ga metamorphism, black serpentinites were oxidized to form red serpentinites, the main type of serpentinite that outcrops today at the Cana Brava mineralized region. Post-metamorphic fluids reactivated the process of serpentinization, thereby generating massive green serpentinite from the red. Green formed on the most fractured zones, and double red and green reaction rims formed on the sides of the veins located outside the green serpentinite zones. This process did not cause significant variation in the volume of the rocks and resulted in a strongly reducing system thanks to the loss of Fe2O3 and iron and the subsequent crystallization of magnetite within veinlets and altered rocks. Low angle shear, developed under brittle conditions, caused hydraulic fracturing and the generation of oversaturated, oxidizing fluids that crystallized the cross-fiber chrysotile inside open fractures. Very densely fractured zones with fractures filled with cross-fiber chrysotile constitute the ore that is mined at present.

Utilização de elipsoide de anisotropia variográfica como indicador cinemático em maciços rochosos fragmentados por falhas - o exemplo do depósito de asbestos crisotila cana brava (Minaçu, GO)

The parameters of a variogram depend on which direction it is calculated, such as the ellipsoid of variographic anisotropy, whose axes indicate the directions of higher, medium and lower continuity of the variable used to calculate the variogram. Consequently, the ellipsoid can be used as a kinematic indicator, since the anisotropy ellipsoids of blocks of the same rock massif or mineralized body will be rotated if the blocks are also rotated. The chrysotile ore body of the Cana Brava Asbestos deposit is composed of 13 blocks separated by faults. Comparing the ellipsoids of variographic anisotropy of the variable amount of chrysotile in these 13 blocks, it was observed that, although they are displaced in relation to each other, in most cases this displacement was not caused by rotation. As a result, it was possible to group some blocks together and use only six ellipsoids and their respective variograms to estimate the amount of chrysotile in the deposit.

The risk of asbestos exposure in South African diamond mine workers

ObjectivesAsbestos is associated with South African diamond mines due to the nature of kimberlite and the location of the diamond mines in relation to asbestos deposits. Very little is known...

The Risk of Asbestos Exposure in South African Diamond Mine Workers

Asbestos is associated with South African diamond mines due to the nature of kimberlite and the location of the diamond mines in relation to asbestos deposits. Very little is known about the health risks in the diamond mining industry. The objective of this study was to explore the possibility of asbestos exposure during the process of diamond mining. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis were used to identify asbestos fibres in the lungs of diamond mine workers who had an autopsy for compensation purposes and in the tailings and soils from three South African diamond mines located close to asbestos deposits. The asbestos lung fibre burdens were calculated. We also documented asbestos-related pathological findings in diamond mine workers at autopsy. Tremolite-actinolite asbestos fibres were identified in the lungs of five men working on diamond mines. Tremolite-actinolite and/or chrysotile asbestos were present in the mine tailings of all three mines. Mesothelioma, asbestosis, and/or pleural plaques were diagnosed in six diamond mine workers at autopsy. These findings indicate that diamond mine workers are at risk of asbestos exposure and, thus, of developing asbestos-related diseases. South Africa is a mineral-rich country and, when mining one commodity, it is likely that other minerals, including asbestos, will be accidentally mined. Even at low concentrations, asbestos has the potential to cause disease, and mining companies should be aware of the health risk of accidentally mining it. Recording of comprehensive work histories should be mandatory to enable the risk to be quantified in future studies.

Reproducibility of asbestos body counts in digestions of autopsy and surgical lung tissue

Asbestos body (AB) counting by a single observer is the most commonly used objective technique to demonstrate asbestos deposition in the lung. In this study, the accuracy and reliability of this procedure is analyzed by evaluating the degree of agreement between two experienced readers. Lung tissue specimens from 66 individuals, most of whom had not been exposed to asbestos, were studied: 35 were obtained in postmortem studies (upper, middle, and lower lung) and 31 were from patients who underwent surgery for lung cancer. Overall, 167 samples were analyzed. Lung tissue sections weighing 0.5 g were obtained prospectively and processed, and the inorganic residue was analyzed by light microscopy at 400× magnification by two experienced readers. Results were expressed as AB/g of dry lung tissue. Interobserver variability was analyzed using the Spearman correlation coefficient and agreement was evaluated by the Bland-Altman method and the kappa index. The interobserver correlation was 0.8975: 0.8029 for autopsy samples and 0.9592 for biopsy samples. Bland-Altman plots showed that most values were grouped around the 95% limits of agreement. The kappa index was 0.87 for all samples, and 0.79, 0.65, and 0.54 for upper, middle, and lower lung specimens, respectively. Asbestos body counting by a single reader is a reliable method, especially at low concentrations of asbestos bodies in lung tissue. Double reading may be indicated in borderline cases with asbestos body levels close to levels of 1 000 AB/g.

Amphibole asbestos soil contamination in the U.S.A.: A matter of definition

Recent concerns surrounding asbestos exposure have extended from occupational settings into natural settings. These developments have caused us to examine the distribution of amphiboles, which are potential asbestiform minerals, within the soils of the U.S.A. Evaluation of mineralogical data from selected sand and/or silt fraction of soils from the USDA-NRCS National Cooperative Soil Survey database shows that soils in all states (except for Rhode Island) contain amphiboles. In 41 of the 50 states, 10% or more sampled pedons contain amphiboles. Overall, 4396 pedons out of the 34 326 pedons (about 13%) sampled in the U.S.A. contained amphiboles. Pedons containing amphiboles ranged from less than 1 to 49% of the pedons among all states. While amphibole asbestos deposits occur in mafic and ultramafic provinces, soil amphiboles occur evenly distributed across the U.S.A. The majority of the amphiboles found in the soils would likely not meet the mineralogical definition of asbestos (i.e., they would not have been derived from asbestiform amphiboles); however, the majority would likely meet a commonly used regulatory definition of a fiber (i.e., are over 5 μm in length with a greater than 3 to 1 aspect ratio). Based on the regulatory definition, 13% of soil pedons and 5% of soil horizons in the U.S.A. are “naturally contaminated.”

Programmed necrosis induced by asbestos in human mesothelial cells causes high-mobility group box 1 protein release and resultant inflammation

Asbestos carcinogenesis has been linked to the release of cytokines and mutagenic reactive oxygen species (ROS) from inflammatory cells. Asbestos is cytotoxic to human mesothelial cells (HM), which appears counterintuitive for a carcinogen. We show that asbestos-induced HM cell death is a regulated form of necrosis that links to carcinogenesis. Asbestos-exposed HM activate poly(ADP-ribose) polymerase, secrete H(2)O(2), deplete ATP, and translocate high-mobility group box 1 protein (HMGB1) from the nucleus to the cytoplasm, and into the extracellular space. The release of HMGB1 induces macrophages to secrete TNF-alpha, which protects HM from asbestos-induced cell death and triggers a chronic inflammatory response; both favor HM transformation. In both mice and hamsters injected with asbestos, HMGB1 was specifically detected in the nuclei, cytoplasm, and extracellular space of mesothelial and inflammatory cells around asbestos deposits. TNF-alpha was coexpressed in the same areas. HMGB1 levels in asbestos-exposed individuals were significantly higher than in nonexposed controls (P < 0.0001). Our findings identify the release of HMGB1 as a critical initial step in the pathogenesis of asbestos-related disease, and provide mechanistic links between asbestos-induced cell death, chronic inflammation, and carcinogenesis. Chemopreventive approaches aimed at inhibiting the chronic inflammatory response, and especially blocking HMGB1, may decrease the risk of malignant mesothelioma among asbestos-exposed cohorts.

Biodurability of chrysotile and tremolite asbestos in simulated lung and gastric fluids

Chrysotile [Mg 3 Si 2 O 5 (OH) 4 ] and tremolite [Ca 2 Mg 5 Si 8 O 22 (OH) 2 ] asbestos represent two distinct mineralogical categories of regulated asbestos commonly evaluated in epidemiological, toxicological, and pathological studies. Human respiratory and gastric systems are sites of asbestos deposition where chrysotile and tremolite asbestos are undersaturated with respect to biological fluids and dissolution kinetics control the persistence of these minerals in biological environments. Here we examined the biodurabilities (i.e., the resistance to dissolution) of chrysotile and tremolite asbestos in simulated body fluids as a function of mineral surface area over time. Batch experiments in simulated gastric fluid (SGF; HCl and NaCl solution at pH 1.2) and simulated lung fluid (SLF; modified Gamble’s solution at pH 7.4) were performed at 37 °C over 720 h to evaluate the dissolution of chrysotile vs. tremolite asbestos in acidic and near-neutral biological fluids. The rate-limiting step of Si release for both minerals was used to obtain rate constants (k) and reaction orders (n) allowing comparisons of mineral dissolution rates. Both chrysotile and tremolite asbestos are less biodurable in SGF (low pH) compared to SLF (near-neutral pH). Based on equivalent surface area comparisons, the surface chemistry of tremolite is more reactive in lung fluid than chrysotile and vice versa in digestive fluid. However, the relative biodurabilities of these asbestos silicates (from most to least) are tremolite (SLF) &gt; chrysotile (SLF) &gt; tremolite (SGF) &gt; chrysotile (SGF) when accounting for the greater surface area of chrysotile per mass or per fiber compared to tremolite. Overall, this study illustrates the importance of surface area and fiber morphology considerations when evaluating the biodurabilities of asbestiform minerals.

Ferruginous bodies in the lungs of the general population during a 45-year period and mineralogical examination

In order to determine the level of asbestos pollution in the lungs of members of the general population in and around Tokyo, the incidence of ferruginous bodies in autopsied or resected lungs during 5 periods over the 45 years from 1937 to 1981 was studied by a light microscopy. Core fibres, after removal of their ferruginous coatings with oxalic acid, and uncoated fibres were analyzed using a scanning electron microscope equipped with a Kevex energy-dispersive X-ray spectrometer. The incidence of ferruginous bodies in 5 g (wet) of digested lung tissue was shown to be 10% in period I (1937-1941), 18% in period II (1947-1951), 70% in period III (1958-1963), 74.4% in period IV (1970-1973) and 81.0% in period V (1980-1981). The major types of core fibres of ferruginous bodies were found to be asbestos, including amosite, crocidolite, chrysotile and the tremolite-actiolite series, but a small number of fibers of materials other than asbestos were also detected. In contrast, a large number of short fibers less than 5 microns in length in 1 g of wet lung tissue were classified as belonging to Mg + Si fibers (the ratio of Mg to Si components being 30% or over) and presumed to be chrysotile. Thus an annual increase in asbestos deposition in lungs of people living in and around Tokyo has been demonstrated and fine chrysotile fibers less than 5 microns in length seem to be the main type of deposited fibers.

Induction of mesothelioma by a single intrascrotal administration of multi-wall carbon nanotube in intact male Fischer 344 rats

The present study assessed a carcinogenic hazard of multi-wall carbon nanotube (MWCNT) in intact (not genetically modified) rodents. MWCNT (1 mg/kg body weight, 7 animals), crocidolite (2 mg/kg body weight, 10 animals) or vehicle (2% carboxymethyl cellulose, 5 animals) was administered to male Fischer 344 rats (12 weeks old) by a single intrascrotal injection. Rats were autopsied immediately after death, when becoming moribund or at the end of the maximal observation period scheduled to be 52 weeks. After 37-40 weeks, however, 6 MWCNT-treated animals died or became moribund due to intraperitoneally disseminated mesothelioma (6/7, 85.7%) with bloody ascites. Peritoneal mesothelium was generally hypertrophic, and numerous nodular or papillary lesions of mesothelioma and mesothelial hyperplasia were developed. While mesothelioid cells were predominant in relatively early stage tumors, advanced stage mesotheliomas were constituted by 2 portions occupied by mesothelioid cells on the surface and spindle-shaped sarcomatous cells in the depth. In the latter, the histological transition was apparently observed between these 2 portions. Mesotheliomas were invasive to adjacent organs and tissues, and frequently metastasized into the pleura. Only 1 rat survived for 52 weeks in the MWCNT-treated group, and similar findings except mesothelioma were observed. All 10 crocidolite-treated and 5 vehicle-treated rats survived for 52 weeks without any particular changes except deposition of asbestos in the former case. It is thus indicated that MWCNT possesses carcinogenicity causing mesothelioma at a high rate in intact male rats under the present experimental conditions. The present data identifies a carcinogenic hazard of MWCNT and will serve as one of the indispensable evidences to be used for the risk assessment crucial for not only protection and improvement of human health and welfare, but also safe and acceptable development and prevalence of this and similar upcoming materials.

Naturally occurring asbestos in eastern Australia: a review of geological occurrence, disturbance and mesothelioma risk

Potential asbestos-bearing rocks account for about 0.2% of the land area of eastern Australia. The main mode of occurrence is as narrow cross fibre and slip fibre veins of chrysotile asbestos in serpentinised ophiolite complexes along the boundaries of major tectonic domains. Smaller deposits of chrysotile and amphibole asbestos occur in metamorphosed mafic and ultramafic rocks associated with the Macquarie Volcanic Arc in New South Wales. Amphibole asbestos is also known from Proterozoic and Palaeozoic amphibolite and from Devonian basalt. Natural asbestos-bearing materials in eastern Australia have been disturbed by mining, road construction, agriculture and forestry, urban development and through natural weathering processes. Persons most at risk of potential exposure to asbestos from natural sources include: farmers who work or live in areas where asbestos-bearing materials may be routinely disturbed by agricultural activities; construction workers involved in large-scale earthwork projects in areas underlain by asbestos-bearing rocks; and quarry workers who unwittingly disturb asbestos-bearing materials. Government authorities and private enterprise need to take geological factors into account to reduce the likelihood of unplanned disturbance of natural asbestos-bearing materials.

Environmental mesothelioma associated with tremolite asbestos: Lessons from the experiences of Turkey, Greece, Corsica, New Caledonia and Cyprus

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, “domestic” exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified “domestic” due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions.

The Geology of Asbestos in the United States and Its Practical Applications

Recently, naturally occurring asbestos (NOA) has drawn the attention of numerous health and regulatory agencies and citizen groups. NOA can be released airborne by (1) the disturbance of asbestos-bearing bedrocks through human activities or natural weathering, and (2) the mining and milling of some mineral deposits in which asbestos occurs as an accessory mineral(s). Because asbestos forms in specific rock types and geologic conditions, this information can be used to focus on areas with the potential to contain asbestos, rather than devoting effort to areas with minimal NOA potential. All asbestos minerals contain magnesium, silica, and water as essential constituents, and some also contain major iron and/or calcium. Predictably, the geologic environments that host asbestos are enriched in these components. Most asbestos deposits form by metasomatic replacement of magnesium-rich rocks. Asbestos-forming environments typically display shear or evidence for a significant influx of silica-rich hydrothermal fluids. Asbestos-forming processes can be driven by regional metamorphism, contact metamorphism, or magmatic hydrothermal systems. Thus, asbestos deposits of all sizes and styles are typically hosted by magnesium-rich rocks (often also iron-rich) that were altered by a metamorphic or magmatic process. Rock types known to host asbestos include serpentinites, altered ultramafic and some mafic rocks, dolomitic marbles and metamorphosed dolostones, metamorphosed iron formations, and alkalic intrusions and carbonatites. Other rock types appear unlikely to contain asbestos. These geologic insights can be used by the mining industry, regulators, land managers, and others to focus attention on the critical locales most likely to contain asbestos.