Review article
Diseases associated with the inhalation of asbestos dust
C.N. Davies
; Pilcox Hall, Tendring, Essex, United Kingdom
Abstract
Examination of publications about asbestosis shows that the disease is caused by breathing asbestos fibres longer than 10-15 µm. Shorter fibres are cleared from the lungs by phagocytes. Soft chrysotile is much more active in the lung in causing asbestosis than any other varieties of asbestos. The relevance of the alleged higher solubility of chrysotile, compared with other varieties of asbestos is uncertain because it is not toxic to phagocytes and the fibres can be extremely fine and difficult to detect, even with a good transmission electron microscope. Solution may result m fragmentation of fibres into short lengths rather than reduction in diameter. Lung carcinoma is also caused by long soft fibres of chrysotile and is peribronchiolar in origin because the curled, splayed fibres do not work their way through the lungs with the aid of the cyclic respiratory movements. Hard, needle shaped, smooth fibres of the amphiboles travel through the lung tissue and if long enough to escape phagocytosis cause carcinoma. Mesothelioma of the pleura is caused by long inhaled fibres of amphibole which have travelled from the airways to the pleura. It can be caused by direct injection or application to the pleura of animals of chrisotile asbestos fibres of any length but does not result from inhalation because the curled, splayed fibres of soft chrysotile anchor themselves in lung tissue and do not travel to the pleura. Selective sampling of airborne asbestos dust is necessary to pick out the small proportion of disease-causing fibres from the considerable amount of short fibre dust which is disposed of by phagocytes before It can do any harm. A selective sampler must sample and retain fibres longer than 10-15 µm, and with diameters in the range 0.1-0.5 µm. It is useless to select on the basis of aerodynamic diameter because such a criterion is insensitive to the length of fibre. Some recent selective sampling systems are described.
Keywords
Hrčak ID:
153817
URI
Publication date:
24.2.1987.
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