Microscopic observations on some fibrous dust samples.

Abstract

Fibers having a diverse range of physical and chemical properties may be emitted into the atmospheric air mostly as a result of human activities. Because the inhalation by man of certain particles may under some circumstances pose a risk to health, this group of particulate matter has to be measured and identified. Because there is little information about the biological (predominantly carcinogenic) potential as yet, measuring techniques are non uniform as well. In this study, the fiber content of human lungdust specimens has been determined electronmicroscopically for 4 different groups: so called normal lungs (as a control), mesothelioma cases, which may have been spontaneous, or initiated by occupational exposure, fibrosis cases (without any lung tumour) after occupational exposure in coal- and talc-mines. In comparison to the mentioned groups some samples from the atmospheric air in the Ruhr District were analyzed for fibers with the aim of obtaining more information about the shape, length and diameter of this particle group. The data indicated that the size distribution of fibrous particles may be highly different depending upon the previous exposure. Furthermore, elongated particles with irregular shapes may confuse the counting and sizing results (preferentially those of the diameters). Based on the present study, fibrous particles greater than 1 micron in length with a length-to-breadth ratio greater than 10: 1 seem to be of increased biological relevance, if mesothelial risk is the main focus of the investigation.