Document rBvpV1Qw6vvK298p322zD98Q0

I ^2 lpl^ - 64 - lung tissue frequently have to be asbestos fibres. The human body, generally speaking, reveals an excellent defence against non-asbestos fibres, nost of them having a diameter >3*.y** Further data given in this chapter will reveal that the more stiff cmphihole fibres, and short chrysotile fibres, may reach the pleura, pas sing through the lung tissue in a mechanical way. Moreover It has been es tablished that in these circumstances asbestos fibres may be found not only in the lungs and pleura, but also in the lymph nodes and spleen (Hcurmann 1966). Uptake through thejSiggstlve tract Uptake of asbestos fibres through the digestive tract occurs in a direct and an indirect way: Direct.: ingestion of fibres In asbestos ?xpoued x-cisons through the mouth. This happens in eating and drinking, in smoking in asbestos contaminated ambient air, in insufficient hygienic conditions of hands and clothing, and in swallowing of asbestos fibres trapped in the nose end mouth from contemineted respiratory air. Indirect: sputum, produced in the normal physiological processes from the lungs and lower respiratory tract, will be swallowed regularly. After expo sure to asbestos containing ambient air a multitude of asbestos fibres will be found in the sputum, either as fibres or as asbestos k>odics (sec chapter vn). Discussions and experiments on the possibility of ir.sestcd asbestos fibres penetrating the intestinal wall are still going cn (l.ce 19?4, Cross 1974), in contrast to the proven passage through the lung tissue. This pos sibility is not excluded and might be v*sponsible for the c::cess incidence of gastrointc-rti r.fcl cancer in cohorts in hc-*.y occupational exposures (see chapter VJ33). .... ^svv In this way asbestos fibres afterwards may he'round in various organs such as the spleen, liver, kidneys, lungs, brains, lymph nodes and blood. 900! 0737 PRODUCED BY FORD