Surface charge and hemolytic activity of asbestos

Light, W.G.; Wei, E.T.

doi:10.1016/0013-9351(77)90012-3

Cited by 94 publications

(30 citation statements)

References 9 publications

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“…For example, the pH of the grinding solution, after a 24-hr run, was 10.5. The zeta potential of chrysotile varies with pH and approaches zero when it reaches 11-12 (Light and Wei, 1977). Hence, grinding in water was equivalent to grinding at zero surface potential charge.…”

Section: Discussionmentioning

confidence: 99%

Grinding of Chrysotile in Hydrocarbons, Alcohol, and Water

Papirer¹

1981

Clays and clay miner.

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Abstract--The change of the properties of chrysotile after ball milling in organic liquids (aromatics, alcohols, silicone oils) or water was studied by gas adsorption, electron microscopy, X-ray powder diffraction, infrared spectroscopy, differential thermal analysis, zeta potential measurements, and chemical analysis. Grinding in low viscosity organic solvents leads initially to a rapid defiberization of the asbestos bundles and to a fragmentation of the isolated fibrils. Finally, amorphization and agglomeration occur causing a drastic decrease of the specific surface area of the ground material. Grinding in water brings about a defiberization, but much more slowly than in organic solvents. Moreover, prolonged grinding in water does not significantly alter the structure of chrysotile. The efficiencies of the organic solvents, considered as grinding aids that induce fracture of the fibrils, are related to the environmental stress cracking of brittle solids (Rehbinder theory). Hence, the pertinent properties of the organic liquids are their viscosity and their cohesion energy (solubility parameter). Solvents chemisorbed on the surface of the ground chrysotile reduce the surface energy of the fracture surface and prevent aggregation. Water does not react according to Rehbinder's theory, but appears to form a protective layer around the fibrils. This hypothesis was verified by dry grinding defiberized asbestos (rapid amorphization) or by disturbing the stability of the water coating by coadsorbing alcohol on the solid surface. Alternaiively, the resistance of the fibrils to fracture may be explained by Westwood's theory that grinding in water is equivalent to grinding in an alkali medium, wherein the surface charge of the chrysotile becomes negligible, and the mechanical stability of the fiber reaches a maximum.

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Section: Discussionmentioning

confidence: 99%

Grinding of Chrysotile in Hydrocarbons, Alcohol, and Water

Papirer¹

1981

Clays and clay miner.

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“…These interactions are attributed to the cationic properties of the fiber. Amphiboles take up dipalmitoyl phosphatidylcholine in vitro, and it could be assumed on this basis that adsorption of surfactant to the fiber occurs in the respiratory tract (6). One might speculate that deposits of biologic material on the surface of fibers in the lungs affect the interaction with phagocytic cells.…”

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confidence: 99%

Comparative studies on the cytotoxicity of amphibole and serpentine asbestos.

Craighead¹,

Mossman²,

Bradley³

1980

Environ Health Perspect

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The chemical and physical properties of serpentine and amphibole asbestos are considered in the context of teir interaction with tissue of the tracheobronchial tree and lungs. In vitro studies in cultures of several types are evaluated and work with the erythrocyte hemolysis system is reviewed. Although fibers ofthe two major mineral types differ substantialy, it is likely they are modified by secretions and membranes of cells after inhalation to the respiratory tract. Investigations using virgin asbestos might not provide an accurate picture of events in vitro.Asbestos is not one, but a family of, hydrated silicate minerals having a fibrous crystalline structure. The types of asbestos differ mineralogically and, as might be expected, these chemical and physical differences are reflected in the mechanism of interaction of fibers with cells. In this paper, we consider comparatively the characteristics of serpentine and amphibole asbestos and attempt to relate these features to the pathogenetic effects on tissues of the respiratory tract. Structural and Chemical PropertiesSerpentine asbestos derives its name from the pliable, curled, "serpentlike" property of the fiber (Fig. 1). Chrysotile, the only commercially important mineral of this type, comprises over 90% of the asbestos mined in the world today. The members of the amphibole asbestos group are more numerous, but have fewer commercial uses. The amphiboles (crocidolite, amosite, and anthophyllite) exhibit a coarse, fibrous structure (Fig. 2).The mineralogy of asbestos is complex and incompletely defined. The types vary in major ele-

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“…After this phase a direct interaction between mineral fibers and PAHs in the lung is not very plausible, which is also suggested in other papers (8). (37). This has lead us to formulate a new hypothesis for the mechanism behind the strong synergism observed between asbestos exposure and tobacco smoking for the induction of bronchial cancer (38).…”

Section: Discussionmentioning

confidence: 99%

Mass Transfer Rates of Polycyclic Aromatic Hydrocarbons between Micron-Size Particles and Their Environment: Theoretical Estimates

Gerde¹,

Scholander²

1989

Environmental Health Perspectives

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This paper presents a mathematical model of how rapidly polycyclic aromatic hydrocarbons (PAHs) adsorb onto initially clean micron-size particles in the ambient air and how fast these substances are likely to be desorbed from the particles after deposition on the surface lining layer of the lung. Results show that, on the one hand, the very low gas-phase concentrations of PAHs in the ambient air should result in a comparatively slow transfer of such compounds to micron-size particles, a process that may last from minutes to hours. On the other hand, the comparatively high solubilities of PAHs in the lining layer of the lung should promote an almost instantaneous release of PAHs onto nonporous particles, and a release within a matter of minutes of most PAHs reversibly adsorbed onto the interior surfaces of porous particles. Two important conclusions can be drawn from this. First, the PAHs in tobacco smoke do not have time enough to interact in the gas phase with other airborne particles before these agents are inhaled into the smoker's lungs. Therefore, adsorption in the gas phase of PAHs onto asbestos fibers can hardly be a characteristic parameter in the mechanism behind the synergistic effect between tobacco smoking and asbestos exposure for the induction of bronchial cancer. Second, the release rate of reversibly adsorbed PAHs from their carrier particles in the lung seems to be so fast that this cannot be a parameter of importance in directly influencing the residence times of such substances in the lung.

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Surface charge and hemolytic activity of asbestos

Cited by 94 publications

References 9 publications

Grinding of Chrysotile in Hydrocarbons, Alcohol, and Water

Grinding of Chrysotile in Hydrocarbons, Alcohol, and Water

Comparative studies on the cytotoxicity of amphibole and serpentine asbestos.

Mass Transfer Rates of Polycyclic Aromatic Hydrocarbons between Micron-Size Particles and Their Environment: Theoretical Estimates

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