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The Editor’s Summary for the article by Tse et al. (2010) stated the following: Assuming an average latency of 42 years, the authors predict that incidence rates will peak in 2009 and that diagnoses will peak in 2014. However, they caution that ongoing use of chrysotile asbestos (which has been implicated but not conclusively established as a cause of mesothelioma) and the release of asbestos fibers from older buildings during demolition or renovation may slow the projected decline. The statement concerning chrysotile asbestos being “implicated but not conclusively established as a cause of mesothelioma” is inconsistent with current scientific opinion. I refer you to the most recent evaluation by the International Agency for Research on Cancer in which Straif et al. (2009) stated, Epidemiological evidence has increasingly shown an association of all forms of asbestos (chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophyllite) with an increased risk of lung cancer and mesothelioma. Although the potency differences with respect to lung cancer or mesothelioma for fibres of various types and dimensions are debated, the fundamental conclusion is that all forms of asbestos are “carcinogenic to humans” (Group 1). In addition, opinions such as that expressed in the Editor’s Summary are advanced only by scientists with prochrysotile industry bias. When I wrote the draft for the first IARC Monograph on asbestos in 1976, which the expert committee accepted and published in 1977 as IARC Monograph Volume 14, a similar conclusion was stated: “Many pleural and peritoneal mesotheliomas have been observed after occupational exposure to crocidolite, amosite and chrysotile.” Since then—more than 30 years—science has not changed its opinion that all forms of asbestos, including chrysotile, cause mesothelioma. In fact, in the article that is the subject of the Editor’s Summary, Tse et al. (2010) did not indicate that chrysotile is not a cause of mesothelioma; on the contrary, they stated the following: Although the mesothelioma incidence is anticipated to decline in the coming decades, it may not decrease to background risk levels given that chrysotile consumption has not been banned under the current legislation and that secondary asbestos exposure from the environment will likely continue. Nevertheless, the hypotheses generated from this ecologic study need further confirmation by subsequent analytic studies. The present study provides supportive evidence for an immediate and global ban on asbestos use. I hope that future Editor’s Summaries will reflect the conclusions of the article and not put forth statements that are not supported by mainstream science. I also support the conclusion of Tse e al. (2010) for “an immediate and global ban on asbestos use.”

Nanosecond time-resolved laser-induced fluorescence spectroscopy was performed on five types of asbestos (chrysotile, crocidolite, amosite, tremolite, and anthophyllite) using an ultraviolet laser pulse of 266 nm. Most of the fluorescence spectra had a broad wavelength band of 350–700 nm and a maximum at approximately 450 nm in the visible region. The spectra also varied in shape over time. Although all the spectra were similar in shape, a significant difference in the relative ratio of fluorescence intensity between the two different wavelength regions was identified. The lifetime and total fluorescence intensity were also investigated and differences were observed for the different types of asbestos. The observed fluorescence decay curves of the different types of asbestos were almost biexponential in form. The total fluorescence intensity for anthophyllite was the largest among the five types of asbestos. Several methods potentially useful for identifying asbestos from other materials on the basis of their fluorescence characteristics are discussed.

Three decades have elapsed since the discovery that the silicates talc and fuller’s earth are potent facilitators of transfection of mammalian cells. Although the possibility of a role for silicate facilitation in silicate-induced carcinogenesis was suggested in 1971, testing for facilitation by the important carcinogen asbestos apparently did not occur until 1984. There then appeared reports showing asbestos facilitated transfection of cultured mammalian cells by various viral RNAs and plasmid and polyomavirus DNA.

We read with interest the recent case report of mesothelioma associated with neighborhood exposure to anthophyllite asbestos [Rom et al., 2001], and a report of asbestosis from occult exposure to anthophyllite [Dodson and Levin, 2001]. However, we wish to correct Rom's assertion that anthophyllite was mined exclusively in Finland and Japan. Five hundred and ten tons of anthophyllite was mined in the Bindi Bindi area of Western Australia during the period 1942-49 [Carter and Lipple, 1982]. The mining was largely open cast and the resulting ore was transported by railway to Perth, the capital city of Western Australia. The ore was then milled in a predominantly suburban area. The majority of the fiber produced was exported to unknown destinations, although some was used locally for boiler lagging, acid resistant filters and oil filters [Johnson, 1948]. It is not known what, if any, dust extraction system was in place at the mill. The current condition of the mine site is not known. However, the area surrounding the mine site was and remains a sparsely populated area and only a small population would be affected by any continuing environmental exposure.

Using the most comprehensive inhalation study available, (Wagner, et al., 1974), the dose-response effects of the four major types of asbestos fibers (amosite, anthophyllite, crocidolite, and chrysotile: Canadian, Rhodesian) for lung cancer have been determined. From linear regression analysis of the animal data and five human epidemiology studies giving a wide range of risk estimates, slopes of the curves have been determined and lifetime risk estimates made. Projected risks for rats are presented with and without surface area (s.a.) conversion factors. On the basis of cumulative exposure, the geometric mean of the point estimates for the human studies (0.0146) is quite close to the geometric mean of the animal data (0.0179 without s.a.; 0.0122 with s.a. calculations). These values also match quite well if one of the studies (McDonald, et al.) is eliminated (geometric mean = 0.031) due to qualitatively different exposure considerations (mining and milling vs. industrial environments). Animal risks based on a concentration per day basis (assuming an average 70-year lifespan for humans) are below the lowest human estimate but within 5-6 fold (less) of the projected risk from nonsmoking asbestos workers (2.2 X 10(-3) using the Hammond et al. study.

The thermal history imprinted on the Hayachine ultramafic complex in the Tono granodiorite aureole has been reconstructed. The contact aureole in the complex can be divided into four zones, from north to south, using critical mineral assemblages as follows: Zone 1 olivine+antigorite+clinopyroxene Zone 2 olivine+talc±tremolite Zone 3 olivine+anthophyllite±tremolite Zone 4 olivine+orthopyroxene±tremolite The mineral paragenesis indicates that the temperature reached at approximately 400°C in the north of the complex, and 750°C at the southern margin. Abundant carbonate minerals were formed in the northern marginal area of the zone 1. The mineral assemblages change (from the northern rim to the middle of the zone) from magnesite+talc, magnesite+talc+antigorite to magnesite+antigorite. The change should have been caused by decreasing in CO2 pressure. The original rock of the complex is probably a residual mantle material (harzburgite with dunite).

Infrared spectra of anthophyllites have been measured in the hydroxyl region (3 800-3 500 cm⁻¹), The principal fine structure absorptions, due to Mg₃OH, Mg₂Fe²⁺OH, etc., are split into hyperfine components whose nature has not been previously recognised., Les spectres infrarouges de plusieurs anthophyllites ont été mesurés dans la région de la vibration de valence du groupement OH (3 800-3 500 cm⁻¹). Les bandes principales présentent une structure hyperfine jusqu'ici inconnue., Law Anthony D. Studies of the orthoamphiboles. II. Hydroxyl spectra of anthophyllites. In: Bulletin de Minéralogie, volume 104, 4, 1981. 12e assemblée générale de l'I.M.A. - Orléans – Juillet 1980. Deuxième partie : inclusions magmatiques / silicates / gemmes / « open session ».

Metapelitic gneisses occuring as lenses and bands within the migmatites of the Gruf-Complex in the eastern Pennine Alps contain various combinations of the minerals quartz, biotite, cordierite, garnet, sillimanite, plagioclase. K-feldspar, spinel, orthopyroxene, anthophyllite and muscovite. The most common rock type is represented by a darkschistosebiotiterichcordierite-garnet-sillimanite-gneiss. A consistent pressure-temperature range of 3–4 kb and 600–650° C has been calculated for the last metamorphic equilibration from six geological thermobarometers.

An attempt was made to characterize the carcinogenic hazard of asbestos fibres by using a set of in vitro screening tests. The fibres tested were the serpentine chrysotile and the three amphiboles anthophyllite, crocidolite and amosite. Their cytotoxic and cytostatic activities in rat primary fibroblast-like cells were assessed along with their effects on enzymic lipid peroxidation by liver homogenates. After 24 hr exposure of fibroblast-like cells to 2.1 μg fibres/cm(2), chrysotile induced the highest cytotoxicity, followed by crocidolite, anthophyllite and amosite. Similarly, after 48 hr exposure, chrysotile had the most growth inhibiting effect, followed by crocidolite, anthophyllite and amosite. Enzymic lipid peroxidation, as measured by pentane or malondialdehyde production, was determined at ambient (21% O(2)) or tissue (4% O(2)) oxygen tension in incubation mixtures containing rat-liver homogenate and asbestos fibres. At 4% O(2), only the two iron-containing fibres, crocidolite and amosite, stimulated lipid peroxidation. The results suggest that the cytotoxic activity is influenced by the surface charge, structure and dimensions of the fibres, and that cell-growth inhibition is associated with surface charge, structure and the Mg(2+) content of the fibres. Effects on enzymic lipid peroxidation appear to be associated with the structure and iron content of the tested fibres. When these results are considered along with epidemiological data, it seems that the carcinogenic potency of asbestos fibres is characterized by an ability to induce high levels of enzymic lipid peroxidation along with moderate cytotoxic and growth inhibiting activities.

A large variety of hornfelses is developed in and around the Coolac Serpentinite, in the aureole of the Bogong Granite. Essentially isochemical metamorphism of partly serpentinized harzburgites has produced metaserpentinites containing variable amounts of talc, tremolite, olivine, orthopryoxene, and other phases: Chromian spinel, partly changed to magnetite and/or ferrichromite, remains as a relict primary phase very near the granite contact. Alumino‐ferromagnesian hornfelses containing amphiboles, spinel, and magnetite, with or without olivine, chlorite, orthopyroxene, and sulphides, as well as cordierite‐antho‐phyllite hornfelses, various calc‐silicate hornfelses and mafic hornfelses, are intimately associated with the metaserpentinites. The chemical compositions of the amphibole‐olivine‐spinel hornfelses can be matched with those of chlorite‐rich and chlorite‐tremolite‐rich rocks outside the thermal aureole produced by reaction‐zone metasomatism of tectonic inclusions within the Coolac Serpent...

The right upper lung lobe of a 74 year old man was resected for a central tumour. Two primary cancers were found; a central small cell carcinoma and a peripheral squamous cell carcinoma. In addition, the peripheral lung tissue showed generalised peribronchiolar fibrosis extending from the non-respiratory bronchioles to the level of the alveolar ducts. Abundant asbestos bodies and large amounts of black dust were seen around the bronchioles. Pulmonary mineral particles were studied by quantitative energy dispersive x ray microanalysis (EDS) using scanning transmission electron microscopy (STEM). The x ray spectra for mineral particles were measured in thin sections, and the characteristic peak intensities of the elements were converted to weight fractions (in oxides). The results enabled the minerals present to be identified and their presence confirmed by calculating the mineral formula. These originated from nine natural minerals, anthophyllite and chrysotile asbestos, talc, and quartz, feldspars, and muscovite, which are components of sand, and also from two artificial mullites used in fire clay. The exposure history of the patient explained the most likely origins of the minerals detected. The patient had been a mason for 23 years, repairing and demolishing stoves and fireplaces and using asbestos for insulation work.

Analysed compositions of coexisting phases from cordierite-amphibole-bearing rocks (cordierite-orthoamphibole-cummingtonite-garnet-staurolite-spinel-opaque ores) and mica schists (garnet-staurolite-biotite-muscovite-plagioclase-andalusite-quartz) have been used in conjunction with experimentally determined equilibria to estimate pressures and temperatures of metamorphism for the rocks of the Outokumpu district. The data do not determine a single point in P-T space, but bracket an area such that T ≈ 600 ± 50°C and P ≈ 3·5 ± 1 kb. These conditions represent the maximum temperature attained by the rocks, and the associated sulphide ore bodies, during the Svecokarelian orogeny and are consistent with a regional palaeogeotherm of c. 50°C/km.Assessment of the composition of the coexisting phases in the cordierite-amphibole-bearing rocks, particularly the Fe-Mg-bearing phases, indicates that it is unlikely that either iron or magnesium was mobile during metamorphism and that the equilibrium assemblage represents essentially isochemical metamorphism of a rock composition that predates the metamorphism. A similar genesis is considered likely for the cordierite-anthophyllite rocks of Orijärvi in southern Finland which forms the basis of the classic statement of the magnesium-metasomatism hypothesis.

Representative consumer talcums and powders, including 20 body powders, baby powders, facial talcums, and also one pharmaceutical talc, were analyzed to determine their mineralogical and chemical composition. Where known, all were formulated prior to 1973. Of the 20 products 10 contained detectable amounts of tremolite and anthophyllite, principally asbestiform, while some also contained fragmented forms of these minerals. The amounts ranged from tenths of a percent to over 14% by weight; two contained detectable amounts of chrysotile asbestos fiber. Eight contained quartz, seven ranging from 2 to 5%, with one as high as 35%. The analyses showed that the consumer products examined were rarely the pure mineral talc, but rather were mixtures of various minerals; some samples consisted of three to five minerals, only one of which was talc. Other common mineral phases included chlorite, platy serpentine, pyrophyllitem mica, and carbonate minerals. Kaolin additive was identified in two products. The single pharmaceutical talc examined contained only a trace amount of quartz. The chemical composition of these products, including both major oxide and trace element content, correlated with their mineral components. Four samples contained substantial concentrations of nickel, cobalt, and chromium, suggesting latice substitution or the presence of trace mineral phases. Geological provenance of the talcs may be ascertained on the basis of chemistry. Possible adverse health effects from intermittent use of these products, especially those that contain asbestiform and fragmented anthophyllite and tremolite, chrysotile, quartz, and trace metals, are presently unknown and warrnat evaluation.

Talc powders from national and international markets were analyzed in order to assess their fiber contents and the proportion of asbestos in the fibrous material. Samples of talc powders used as excipients in pharmaceutical and cosmetic preparations demonstrated fiber contents up to 30% of total particles. About a half of the talc powders revealed the presence of asbestos: in five samples chrysotile (a serpentine asbestos) was present, in the other ones tremolite and anthophyllite (an amphibole asbestos). The amounts of asbestos vary up to 90% in the different samples of the fibrous fraction. About 75% of observed asbestos fibers were thinner than 0.4 micron, i.e., below the resolving power of light microscopy which until now was the most utilized technique for evaluating the environmental pollution due to asbestos.

The Agnew nickel sulfide deposit is spatially associated with a lenticular body of ultramafic rocks which shows a concentric zonation in metamorphic mineralogy. Olivine + tremolite + chlorite + cummingtonite ±enstatite assemblages occur at the margin of the ultramafic lens, giving way to olivine + anthophyllite, olivine + talc and olivine + antigorite assemblages successively inwards. These rocks are interpreted as having crystallized from komatiitic lavas, and exhibit a spectrum of compositions from those of original flow tops to pure olivine adcumulates. The relative modal abundances of metamorphic olivine, tremolite and chlorite reflect original proportions of cumulus olivine and komatiite liquid in the protolith. Peak metamorphic conditions are estimated at 550° C, based on garnet-biotite thermometry, at a maximum pressure of 3 kb. This temperature falls within the narrow range over which metamorphic olivine may co-exist with enstatite, anthophyllite, talc or antigorite depending upon the fugacity of water in the metamorphic fluid. The observed mineralogical zonation is therefore attributed to infiltration by CO2-rich fluids, generated by decarbonation of talc-carbonate rocks formed during pre-metamorphic marginal alteration of the ultramafic lens. Metamorphic fluids were essentially binary mixtures of water and CO2, with minor H2S having a maximum partial pressure less than 1 percent of total pressure. Enstatite-bearing assemblages formed in the presence of CO2-rich fluids at fluid: rock volume ratios close to one, while anthophyllite, talc and antigorite bearing assemblages formed in the presence of progressively more water-rich fluids at progressively lower fluid-rock ratios.

The surface area of anthophyllite asbestos variants with different stages of fiber development is found to be not proportional to the fineness of the fibrils. Coarser variants have transitional pores whereas the asbestiform is microporous. HRTEM images show structural intergrowths of $Mg(OH)_2$ in an anthophyllite lattice, whereas the intergrowths are absent in the asbestiform anthophyllite. Conversion of brucite intergrowth into a noncrystalline phase results in the generation of transitional pores.

The hornblende-bearing basic gneisses in the Uvete area, central Kenya, were metamorphosed under a narrow range of P and T (6.5 ± 0.5kbar and 530 ± 40°C) of the staurolitekyanite zone in the Mozambique metamorphic belt. They show a wide variety of divariant and trivariant mineral assemblages consisting of hornblende, cumminatonite, gedrite, anthophyllite, chlorite, garnet, epidote, clinopyroxene, plagio-clase and quartz. The bulk and mineral chemistries and the graphical representation of phase relations show that each mineral assemblage approaches chemical equilibrium and defines a unique composition volume in the A′(Al + Fe3+− (13/7)Na)-F(Fe2+)-M′(Mg)-C′(Ca-(3/7)Na) tetrahedron. The composition volumes are distributed quite regularly and do not overlap each other. The phase relations in the Uvete area are in contrast with those in the staurolite-kyanite zone amphibolites in the Mt. Cube quadrangle, Vermont. The amphibolites there contain low-variance mineral assemblages formed under different values of μH2O and μCO2. These assemblages define overlapping composition volumes in the A′-F′-M′-C’tetrahedron. The mineral assemblages in the Uvete area are interpreted as having formed in equilibrium with fluid at a high and nearly constant μH2O value. Such a fluid composition was externally controlled by the supply of H2O-rich fluid expelled from the surrounding pelitic and psammitic rocks. The body size of the basic gneisses in the Uvete area (less than 400m in thickness) was small enough for the fluid to migrate completely.

Hyperfine parameters of 57Fe in anthophyllites (Mg2+, Fe2+)7 Si8O22(OH, F)2 mainly depend on the amount of Al present in the structure. The quadrupole splitting of the doublet due to Fe2+ in M1, M2 and M3 decreases systematically with the Al content, whereas that of the doublet due to Fe2+ in M4 and the half-width of the combined M1, M2, M3 doublet increases. Structurally these variations suggest that, with the incorporation of Al (miscibility towards gedrite), the distortion of the M4 polyhedron decreases, whereas the M1, M2 and M3 polyhedra become more distorted and dissimilar.

Sections perpendicular to [001] of ion-thinned specimens of amosite (fibrous grunerite) from Penge, Transvaal and anthophyllite from Paakila, Finland and Söndeled, Norway, have been examined by high-resolution transmission electron microscopy. Observations on the nature of grain boundaries and alteration are compared with those of other workers on other fibrous amphiboles. Fibrous crystals grow with their fibre (c) axes approximately parallel to one another but they have considerable rotational disorder about that axis. Grain boundaries are generally irregular in shape and only follow low-index planes for short sections. In all specimens the amphibole has undergone some alteration to sheet silicates along grain boundaries, fractures, cleavages, and multiple-chain lamellae. Anthophyllite alteration products are talc, serpentine and chlorite, and amosite alteration products approximate to iron analogues of talc and serpentine. Talc layers are generally planar and their orientation is strongly controlled by the amphibole structure, whereas serpentine and chlorite layers often curve and their orientations are less frequently related to that of the amphibole. Comparison of specimens which appear finely fibrous in hand specimen with those which appear coarser, acicular or massive suggests that the nature of fibres produced by crushing is mainly controlled by the grain boundaries in the former type, but other factors such as fractures, cleavages, and defects are more important for the latter types.

Fibroblasts exposed to chrysotile B asbestos displayed an initial growth inhibition compared to controls during the first 24 hr of incubation. At 48 hr, however, there was resumption of cell proliferation as evidenced by elevated thymidine (TdR3H) incorporation. UICC samples of chrysotile A, chrysotile B, crocidolite, amosite, and anthophyllite all altered thymidine incorporation by lung fibroblasts in a dose-dependent manner and to different maximal levels. Amphibole asbestos was either equally or less active than chrysotile. Silica had the lowest activity. Various other particles, including latex, zymosan, titanium dioxide, magnetite, and Mt. St. Helens volcanic ash, had no effect. Chemically modified chrysotile samples which retained their fibrous structure were also tested for possible alterations of fibroblast thymidine incorporation. The DNA synthesis response of human lung fibroblasts to asbestos correlates with its in vivo fibrogenic and tumorigenic potential and may prove useful in determining the pathological effects of asbestos.

Mineral equilibria in the MgO--SiO/sub 2/--H/sub 2/O system were investigated, with emphasis on the stability relations of talc, antigorite, forsterite, anthophyllite, and enstatite. Thermal dehydration temperatures at 1 kb H/sub 2/O are at 514/sup 0/ +- 12/sup 0/C (Ta--Antig--Fo), 627/sup 0/ +- 7/sup 0/C (Ta--Fo--Anth), 670/sup 0/ +- 7/sup 0/C (Anth--Fo--En), 675/sup 0/ +- 7/sup 0/C (Ta--Anth--Q), 643/sup 0/ +- 8/sup 0/C (Ta--Fo--En), 690/sup 0/ +- 8/sup 0/C (Ta--En--Q), 729/sup 0/ +- 8/sup 0/C (Anth--En--Q). Derived G/sup 0//sub f/ values in kcal/gf are -928.756 +- 1.1 (Antig, based on Mg/sub 2/./sub 825/Si/sub 2/O/sub 3/ (OH)/sub 3/./sub 65/), -2711.320 +- 1.7 (Anth) and -348.955 +- 0.6 (EN). Anthophyllite has a relatively narrow temperature stability range at 1 kb, but it increases as P/sub H/sub 2/O/ increases. The Ta--Fo--En and Ta--En--Q reactions are low-pressure changes, metastable at 1 kb. The (Q) and (Fo) invariant points are at approximately 603/sup 0/C, 500 bars, and 601/sup 0/C, 175 bars, P/sub H/sub 2/O/, respectively. Higher P/sub total/ raises and spreads the P/sub H/sub 2/O/ values of the invariant points. The log SiO/sub 2/ /sub aq/ versus 1/T diagrams utilized in this study are applied to metasomatic and isochemical processes involving this system. Aspects of contactmore » metamorphism and metasomatism, the process of serpentinization, and compositional controls and relative stabilities of the serpentine phases are discussed. Isochemical cooling in the subsolidus at finite, though not necessarily constant, P/sub H/sub 2/O/ results in a mineral reaction series analogous to that of the classical reaction series of silicate melts. The chemical constraints revealed in the various equilibria studied help to clarify and more rigorously to define the isochemical PT relationships of the system. The geological application of activity-activity or chemical potential diagrams is also discussed, and the necessity of considering reactions that correspond to or approximate the true process involved is illustrated.« less

Cordierite-hypersthene rocks with a chemistry comparable to the cordierite-anthophyllite rocks of Orijarvi have been found in the high-grade West Uusimaa Complex, SW Finland. Chemistry, petrography, and spatial relations indicate that the cordierite-hypersthene rocks represent the high-grade equivalents of the Orijarvi cordierite-anthophyllite rocks. Metamorphic conditions for the Orijarvi and West Uusimaa Complex occurrences are estimated at respectively 550–650°C, 3–5 kbar, low H 2 O activity and 710–810°C, 3–5 kbar, low H 2 O-high CO 2 activity. Cordierte-anthophyllite rocks are generally associated with massive CuPbZn deposits. It is suggested that the cordierite-hypersthene rocks might be potential guides to CuPbZn deposits in high-grade regions.

Malignant mesothelial tumors have been reported for at least 100 years but now appear more common. Between 1959 and 1976, 4539 fatal cases were reported from 22 countries. Evidence suggests that the annual incidence in Canada since 1965 has been about 10 per million in males aged 45 years and over but much lower at younger ages and in females. Ratios were calculated for cases observed in population surveys to numbers expected from Canadian experience. In nine countries with data, ratios ranged from 0.8 to 2.1; in certain cities, mainly with shipyards, ratios were much higher, many around 7 and some above 20. Two hundred and sixty-eight cases were reported in occupational surveys: Proportional mortality rates ranged from 5.2 to 8.8% in insulators, 0.8 to 6.9% in asbestos factory workers, and 0 to 0.19% in anthophyllite or chrysotile miners and millers, compared with 0.03 to 0.06% in general populations. Rates could not be calculated for crocidolite, but most cases in production workers were associated with this fiber type. The evidence suggests a gradient in mesothelioma-inducing potential, by type of fiber, from crocidolite down to chrysotile and anthophyllite. The special hazards of insulation and shipyard work are still not fully explained.

The adsorption behaviour of different asbestos varieties for N,N-dimethylaniline and its catalytically formed oxidation products e. g. Methyl Violet is studied using laser microprobe mass analysis (LAMMA) in laser desorption conditions. The results prove that amosite and chrysotile adsorb more easily than crocidolite, whereas anthophyllite does not give rise to a detectable adsorption. In the presence of hydrogen peroxide, the method developed shows potential for the investigation of the surface reactivity of pure and industrially transformed asbestos and other fibrous materials.

Lung tissue samples from 78 cases from autopsy of mesothelioma in Canada, 1980 through 1984, and from matched referents were examined by optical and analytical transmission electron microscopic study. Concentrations of amosite, crocidolite, and tremolite fibers, and of typical asbestos bodies discriminated sharply between cases and referents. The distributions of chrysotile and anthophyllite/talc fibers and of all other natural and man-made inorganic fibers (greater than or equal to 8 microns) in the two series were quite similar. Relative risk was related to the concentration of long (greater than or equal to 8 microns) amphibole fibers with no additional information provided by shorter fibers. The proportion of long fibers was much higher for amphiboles than chrysotile and, except for chrysotile, systematically higher in cases than referents. Amphibole asbestos fibers could explain most mesothelioma cases in Canada and other inorganic fibers, including chrysotile, very few. Fibrous tremolite, contaminant of many industrial minerals including chrysotile, probably explained most cases in the Quebec mining region and perhaps 20% elsewhere.

The ability of different mineral fibres to induce morphological transformation of Syrian hamster embryo cells has been studied. Increased transformation frequencies were obtained in the presence of chrysotile, crocidolite, amosite, anthophyllite and the glass fibres (GF) 100, while no significant increase in transformation frequency was observed with GF 110 and TiO2. Chrysotile was the most potent of the fibres tested. GF 100 was more potent than crocidolite, amosite and anthophyllite. By comparing transformation frequency and toxicity, it could be concluded that induction of transformation is not caused by unspecific cytotoxic effects. In contrast to some earlier studies, no synergistic effect was observed between benzo[a]pyrene (BaP) and asbestos fibres. Adsorption of BaP to crocidolite fibres had no effect on the transformation frequency. Moreover, crocidolite was not able to promote the transformation of cells pre-exposed to BaP. Electron microscopy studies showed that the fibres were rapidly phagocytosed. Blebs were often formed on the cell surface and were most pronounced after crocidolite exposure. The blebs did not seem to be associated with the areas of physical interaction between the cells and the fibres, but were distributed throughout the cell surface.

Lamellar nigerite is found in Zn-rich spinel from a sample that contains chiefly anthophyllite + spinel + cordierite, lesser amounts of quartz and chlorite, as well as sphalerite, pyrite, pyrrhotite, and galena, and rare cassiterite and rutile. Nigerite can be described as interlayering of spinel-like (R2+Al2O4) and nolanite-like ((Sn, Ti)Al4O8) structures. In nigerite, the spinel-like part is also compositionally related to spinel, but in the nolanite-like part only the structural analogy exists. Stoichiometric assumptions that relate the anhydrous cation sum to the amount of R4+ cations present, allow Fe3+ estimates from microprobe analyses, and a representative analysis gives the following anhydrous formula: Mg1.30Fe 0.65 2+ Zn3.03Mn0.03Al11.65Fe 0.35 3+ Sn0.32Ti0.18O24.

The predominant asbestos fibre type used in the production of asbestos cement is chrysotile. The use of asbestos in relation to fibre type in a Norwegian asbestos cement plant during 1942-80 was 91.7% chrysotile, 3.1% amosite, 4.1% crocidolite, and 1.1% anthophyllite respectively. Electron microscopy and x ray microanalysis of lung tissue samples of asbestos cement workers who had died of malignant pleural mesothelioma or bronchogenic carcinoma showed a completely inverse ratio with regard to fibre type. The percentage of chrysotile asbestos in lung tissue varied between 0% and 9% whereas the corresponding numbers for the amphiboles were 76% and 99%. These differences are discussed with respect to the behaviour of different fibre types in the human body and to the occurrence of malignant mesothelioma in this asbestos cement factory.

Surface charge, represented by zeta potential, and hemolytic activity were measured for the five asbestos reference samples of the International Union against Cancer (UICC). Zeta potentials in distilled water at pH 7.4 for chrysotiles A and B were +40.5 and +52.5 mV, and for amphiboles crocidolite, amosite, and anthophyllite were −50.4, −58.5, and −54.0 mV, respectively. For fiber samples of equal surface area, chrysotiles had a greater hemolytic activity than amphiboles: 60.5 and 81.9% for chrysotiles A and B compared to 7.7, 9.8, and 15.7% for crocidolite, amosite, and anthophyllite, respectively. A lysing mechanism based on charge polarity is proposed to account for this difference in activity. Zeta potential and hemolytic activity were reduced by adding the main component of pulmonary surfactant, dipalmitoyl phosphatidylcholine (DPPC), to fiber suspensions. DPPC was more effective in decreasing both zeta potential and hemolytic activity for amphiboles than for chrysotiles. On the basis of these reductions, a significant correlation (r = 0.84) was found between zeta potential and hemolytic activity for all five UICC samples. This correlation suggests that surface charge is the principal factor in hemolysis by asbestos. The relevance of surface charge to asbestos toxicity is discussed.

In this paper, the method that utilizes the X-ray diffraction technique combined with a procedure for X-ray absorption correction, already applied to chrysotile, was extended to the quantitative determination of microgram quantities of four types of amphibolic asbestos. These are: crocidolite, amosite, tremolite and anthophyllite. The effectiveness of the absorption correction procedure, based on the use of a silver membrane filter, was tested for crocidolite by preparing standards of this substance in three different matrices and comparing their diffractometric responses with those of pure analyte standards. These experimental data were also used to calculate the mass absorption coefficients of the matrices, which were compared with both the theoretical values and the values obtained in previous experiments where chrysotile was used as the analyte. The limits of detection of the four pure amphiboles, and crocidolite in matrix were established, and a detailed study of the most common interference...

Fitted Mössbauer spectra are presented for a set of anthophyllites and gedrites. Despite their complexity it is possible to obtain fits for gedrite spectra and the Mössbauer parameters are consistent with results for anthophyllites from this and previous studies. At least three doublets are required to fit the Fe2+ absorption in gedrites; there is no single model at present to explain the behaviour of the spectra. Fe3+ absorption is also resolved.

EARLY BEGINNINGS Asbestos has been known in various forms and used for different purposes since prehistoric times. In Finland, for example, pottery dating from 2500 B.C. has been found to incorporate asbestos (presumably anthophyllite) fibers, and Busmanoid pottery attributed to stone-age times (before the middle of the first century B.C.) has been found containing amphibole in the region ranging from southern Sudan to northern Kenya (70, 93). Finnish peasants are also reported to have used asbestos rock to pack crevices in their log huts from time immemorial. One of the earliest historical records tells of the use of asbestos wick in a gold lamp for the goddess Atbene in the fourth to fifth century B.C. At the turn of that century Theophrastus described the persistence of the wick after the oil was burned off, and Strabo and Plutarch continue the story (28, 44, 84). Herodotus, writing about 456 B.C., remarks on the use of an asbestos cloth for retaining the ashes of the dead during cremation, and Pliny in the first century A.D. calls it the funeral dress of kings. Such a shroud is reported to have been recovered from a pre-Augustinian tomb (23b, 44, 50). Plutarch described other articles into which the material was woven. One form of the Greek word oau@~os signified “unquenchable;” the perpetuity of the flame given by wicks containing asbestos would have justified the appelation. The concept of indestructibility seems to have been added to the connotation later. Some confusion has resulted from another formrjao/Iaoro~ of the same word that signified what today we would call slaked lime (95). The term “amiantos” and its variations, common in mediterranean countries, also has a confused etymology. Lithos amiantos is said to be the original term, as used by the Greeks to indicate a rock unstained, untainted, or undefiled, referring presumably to the cleansing of asbestos material by fire (19). It has been suggested, however, that the Karpasian flax referred to by Pausanius (second century A.D.) came from a village in Cyprus known as Amianto, which might be the town of Amiandos near which chrysotile has been found in recent times. In England, the term “amianthus” survived until the end of the 19th century, when the word “asbestos” took its place. In France today, “amiante” is used at least as frequently as “asbeste.” The property of being unconsumed and even purified by fire is emphasized in the account given by Marco Polo (ca. 1250 A.D.) of a cloth reputed to be of salamander skin, but actually consisting of “amianto” prepared from rock by a process that persisted well into the nineteenth century (50). Apparently a similar account given some 150 years earlier did not attract antiquarian interest (48). The story of Charlemagne’s tablecloth and the impression made on guests when he threw it into the fire has been many times recounted in recent literature (21, 50).

An examination of postmortem lung tissue from 20 cases of diagnosed asbestosis from the Canadian chrysotile mining industry has shown that fibrous minerals other than chrysotile were present in many of the cases. Tremolite fiber was found in 11 of the cases, often in large amounts, and crocidolite and amosite fibers were found in 2 of the cases. Fibers corresponding to talc and anthophyllite were found in 3 cases. In 4 of the cases, fibers were not detected. Amphibole and other fibers were found to be present in larger numbers than chrysotile in 7 of the cases. No attempt has been made to relate the results to occupation and location where the exposures may have occurred. It is possible, however, that fibrous minerals other than chrysotile are active in the incidence of asbestosis in the Canadian chrysotile mining industry.

I analyzed the total pulmonary asbestos burden in the lungs of 9 chrysotile miners who had asbestos airways disease (so-called "early asbestosis") but no evidence of classic asbestosis (interstitial fibrosis) on pathologic examination. The results were compared with values found for 9 miners matched for age, sex, smoking, and work length who had no histologic evidence of asbestosis or asbestos airways disease. The mean value for chrysotile fibers in the airway disease group was 47 X 10(6)/g dried lung, compared with 23 X 10(6) in the group without lesions (p less than 0.04). For contaminant amphiboles, probably derived from the chrysotile ore (tremolite, actinolite, anthophyllite), the corresponding values were 106 X 10(6) versus 58 X 10(6) (p less than 0.06), and for total asbestos fibers, 153 X 10(6) versus 81 X 10(6) (p less than 0.06). There was a strong correlation between amount of chrysotile and amphibole for each case, suggesting that the amphibole was probably a good measure of the original (but no longer present) chrysotile burden. No differences were seen between the 2 groups with regard to fiber size distribution, aspect ratios, or fiber widths. I conclude that the overall differences in fiber concentration between the 2 groups, although significant, are sufficiently small enough to suggest that other factors may be involved in the genesis of small airway lesions.

The acute response of the rat lung to a range of fibrous materials has been investigated by bronchopulmonary lavage, at dose levels of 0.5 and 1.0 mg, 1 and 7 days after their administration by intratracheal instillation. The materials chosen for study included UICC chrysotile A, amosite, crocidolite and anthophyllite, and samples of S. African "long" amosite and glass fiber. In addition, the subacute response to 1, 2 and 3 mg of chrysotile and amosite has been studied at 50 and 100 days after instillation. In the acute phase at 1 day after instillation, the response to chrysotile was greater than that to any of the other materials, but by 7 days there was no gradation in the response to different dusts. In the subacute phase, cell recoveries were low, and it was not possible to assess the long-term cytotoxic or fibrogenic effects of amosite and chrysotile by analyses of lung washes, even though biochemical and histological methods indicated gross changes in lung pathology.

Mast cell counts were performed on sections taken from the lungs of rats exposed by inhalation to different UICC samples of asbestos fibres for periods ranging from a few days to two years. A comparison of mast cell counts with grades of fibrosis showed that there is a sevenfold increase when there is interlobular linking of the fibrotic lesions (grade 5). Submesothelial mast cells showed a trend of increasing numbers with increasing exposure and with increasing subpleural thickening. Each type of asbestos produced a steady increase in mast cell numbers with increasing exposure. Two samples from animals exposed to chrysotile and two from animals exposed to amphiboles (crocidolite and amosite respectively) had 10 times as many cells as the control group after six and 24 months' exposure. Another amphibole, anthophyllite, produced 50 times more cells than were present in the control specimen appropriate for the heaviest exposure. These results are briefly discussed in relation to further exposure, smoking, and characteristics of the dusts.

The extent of the validity of the Rayleigh—Debye—Gans theory when applied to fiber-like particles is discussed. It is shown that the theory can be used to obtain information on the diameter and aspect ratio distribution functions of aligned UICC anthophyllite fibers by fitting experimental results by V. Timbrell (Microscope20, 365 (1972)). The determination of the same distribution functions by fitting preliminary experimental results by this author for randomly oriented fibers is also discussed.

SummaryA pure anthophyllite schist occurs as a bedded deposit conformable with garnet-bearing quartz—muscovite, and quartz—chlorite—biotite schists and diopside-bearing caic-silicate rocks in the north-central part of the Nellore Schist Belt. Field and petrochemical studies show that anthophyllite schist has formed from regional metamorphism of Fe-, Mg-rich aluminous sediments aided by metamorphic differentiation due to local kinematic action under amphibolite facies conditions which is the general grade of metamorphism of the Nellore Schist Belt. A pure anthophyllite schist of sedimentary origin reported here is the first of its kind described from any terrain.

Malignant mesotheliomas of the pleura and peritoneum are well-recognized risks of asbestos exposure. We determined the asbestos body content of the lungs from 24 cases of malignant mesothelioma (19 pleural, five peritoneal) and compared such to the content of lungs from 50 consecutive adult autopsies and four cases of overt asbestosis using a Clorox-digestion concentration technique. The cores of 90 asbestos bodies were examined by energy dispersive x-ray analysis and compared with similar data from 120 standard asbestos fibers and 20 fiberglass fibers. The malignant mesothelioma patients had asbestos body counts intermediate between those of the general population and those of patients with asbestosis, although some of the mesothelioma cases overlapped with the general population. These latter cases often lacked an identifiable occupational exposure to asbestos. EDXA studies demonstrated an amphibole core in 88 of the 90 asbestos bodies (amosite or crocidolite in 80 of 88, anthophyllite or tremolite in eight of 88), and chrysotile in two instances.

The contents of collagen, hexosamine, phospholipids, and cholesterol and the activities of acid and alkaline phosphatases, glutamic oxalo-acetate transaminase, glutamic pyruvate transminase, aldolase, hexokinase, and lactic dehydrogenase were determined in the lungs of rats 150 days after the intratracheal injection of amosite, anthophyllite, and chyrsotile. Anthophyllite did not cause any significant change, while amosite and chrysotile caused significant increases in the contents of collagen and mucopolysaccharides. Lactic dehydrogenase and acid phosphatase activities were increased by all the dusts, while the othe enzymes were not seriously affected. The biochemical significance of the findings in relation to abestosis was discussed.

Serpentinized ultramafic rocks and Sangun metamorphic rocks occur in the Sasaguri area, Fukuoka Prefecture. Lizardite and antigorite are the most abundant rock-forming minerals in the Sasaguri ultramafic rocks and are accompanied by lesser amounts of chrysotile (2Mcl and 2Orcl), magnetite, chromite, pyrite, pentlandite, millerite, forsterite, chlorite, talc, tremolite, anthophyllite, calcite, dolomite, magnesite, aragonite, hydromagnesite, artinite, brucite, pyroaurite, coalingite, szaiberyite, sepiolite, and deweylite, Serpentinites can be divided into following four types by the assemblage and grain size of serpentine minerals: (1) lizardite serpentinite, (2) lizardite-antigorite serpentinite, (3) fine-grained antigorite serpentinite, (4) coarse-grained antigorite serpentinite. The representative rock-forming serpentine minerals (five antigorites and one lizardite) and the two vein-forming fibrous chrysotiles in lizardite serpentinite were examined by X-ray, chemical, electron optical, thermal, and infrared absorption analyses. The significant differences in chemical composition and structural properties of antigorties are found. Fine-grained antigorites have low Fe contents (total FeO=1.6-2.5 wt%) and long supercell parameters (A=41.8-42.5 A), and coarse-grained antigorites have high Fe contents (toal FeO=4.9-6.0 wt%) and short supercell parameters (A=35.4-40.5 A). Lizardite and chrysotile show low Fe contents (total FeO=1-3 wt%). Many lizardite serpentinites in this area contain chrysotile 2Mcl. Its proportion is approximately 20 to 30 wt%. Povlen-type chrysotile is found in the vein-forming chrysotile specimen by electron microscope examinations.

Fibrous specimens of tremolite, amosite, crocidolite and anthophyllite have been studied by electron diffraction and high-resolution microscopy. Amosite (and to a lesser extent crocidolite) are shown to be subject to frequent twinning on (100) leading to stacking disorder, and an explanation is provided of previously supposed anomalies in their diffraction patterns [Chisholm (1973), J. Mater. Sci. 8, 475-483]. Tremolite is sensibly free from these defects and this is explained in terms of crystal chemistry. The presence of Wadsley defects of the type suggested by Chisholm has been confirmed in tremolite, amosite and anthophyllite, and these defects have been shown to correspond to intercalation of lamellae of triple-chain structure parallel to (010). In anthophyllite these lamellae are observed to segregate into domains.

Cordierite-anthophyllite rocks from the aureole of the Falun sulfide deposit are characterized by the assemblages cordierite + anthophyllite + garnet + gahnite + quartz, dierite + staurolite + quartz and cordierite + andalusite + quartz. Metamorphic conditions are estimated to be 550 ± 50° C , 2.5 ± 1 kbar. Bulk rock chemistry, trace element concentration and the variance of the system as defined by the parageneses hint at an origin from acid rocks altered metasomatically at rather low temperatures to chlorite + quartz ± muscovite and subsequently metamorphosed under essentially isochemical conditions.