Considerable progress in understanding how inhaled minerals cause disease in man has been made in the past two decades. This is mostly due to the great amount of human, animal and cell multidisciplinary studies carried out on silica, asbestos and asbestiforms all around the world. Two previous NATO Workshops on "In Vitro Effects of Mineral Dusts on Cells", have been published in the NATO ASI Series (1985 and 1989). The present NATO-INSERM workshop has focused specifically on a group of silicates, named phyllosilicates because of their sheet structure, of which health related effects have been poorly and sporadically investigated. These silicates are presently largely used as filling materials (kaolin, talc, chlorite), insulating materials (vermiculite, micas), adsorbants (sepiolite, attapulgite) and in many other industrial applications. The estimated annual world production is presently 5.5 million tons of talc (1.8 million for Europe) and only in the United Kingdom about 3.5 million tons of kaolin.

Klappentext

This overview covers health related effects of a special group of silicates, named phyllosilicates for their structure (non-fibrous platty crystals), and known for their industrial uses (filling, insulating, adsorbing materials). Their most important contaminant, asbestos, is also discussed. The different chapters describe the present knowledge concerning geology, mineralogy and health related effects (epidemiology, pathology, animal experiments, cell toxicology, carcinogenesis) of phyllosilicates.

Inhalt
I Physico-Chemistry of Non Fibrous Phyllosilicates.- 1. The mineralogy of phyllosilicates.- 2. Geological occurrence of phyllosilicates. Application to kaolinite, talc, sepiolite and palygorskite deposits.- 3. Phyllosilicates as industrial minerals.- 4. Surface properties of phyllosilicates.- 5. Phyllosilicates: associated fibrous minerals.- 6 Concentrations of fibres in phyllosilicates.- 7. Talc. A morphological study on pseudomorphs.- 8 The physical characterization of muscovite and kaolinite dusts.- 9 Asbestos content of talcs from italian mines and fibre concentration in various commercial talcum powders used in Italy.- 10. Occurrence of Phyllosilicates in tobacco.- 11. The effect of the surface quality on the fibrogenicity of the phyllosilicates muscovite and kaolinite.- 12. Oxidizing surface properties of divalent iron-rich phyllosilicates in relation to their toxicity by oxidative stress mechanism.- 13. Solubility and surface properties of talc in a physiological fluid. Results of in vitro experiments at 37°C.- 14. Mineralogy of talc deposits.- II Clinical and Epidemiological Evidence of Health Effects after Occupational Exposure.- 1. Respiratory disease from occupational exposure to non-fibrous phyllosilicates.- 2. Pathological features of pulmonary disease due to silicate dust inhalation.- 3. Clinical aspects of kaolin pneumoconiosis.- 4. French talc pneumoconiosis.- 5. Talc pneumoconiosis in Italy.- 6. Human pathology of kaolin and mica pneumoconioses.- 7. Palabora vermiculite.- III Health Related Effects after Non Occupational Exposure.- 1. Talc: its cosmetic, addictive and therapeutic uses and their effects on health.- 2. Therapeutic and domestic uses of attapulgite and sepiolite.- 3. Lung retained minerals correlated with smoking, emphysema andlung cancer.- 4. Mineral particulate in the lung parenchyma of subjects not occupationally exposed to dust.- IV Fibrogenesis Carcinogenesis. Animal and Cell Responses to Phyllosilicates.- 1 Hypotheses on the mechanisms of carcinogenesis and cell transformation by asbestos and other mineral dusts.- 2. Review on pulmonary effects of phyllosilicates after inhalation.- 3. Intraperitoneal injection studies for the evaluation of the carcinogenicity of fibrous phyllosilicates.- 4. Review of short-term tests used for the toxicological evaluation of phyllosilicates.- 5 Toxicity of phlogopite and muscovite in vitro.- 6. Kaolin generates °OH and causes hemolysis by acting as a Fenton reagent.- 7. Some in vitro and in vitro studies carried out with talc samples.- 8. Slate dust toxicity.- 9. Biological effects of mica dust in experimental animals.- 10. Assessment of the fibrogenicity of attapulgite.- 11. Pulmonary toxicity of kaolin in rats exposed by inhalation.- V Implications in Industrial Hygiene and in Public Health.- 1. The scientific basis for controlling exposures to phyllosilicate dust at the workplace.- 2. Control limit values in different industrialized countries: USA.- 3. Limit values: the European dimension.- 4. Occupational exposure limits for phyllosillicates in the United Kingdon.- 5. Occupational exposure limits in France.- Conclusions.