Electron microscopic analyses of dust from the lungs and the lymph nodes of talc-mine employees

The primary purpose of the present study was to obtain microscopic analyses of the lung and lymph-node dust samples from 12 deceased Austrian workers who had been exposed occupationally to dust of talc and other mineral impurities in a talc deposit for many years. The results of the analyses of both fibers and particles are presented. A second goal of the study was to search for a relationship between different grades of pneumoconiotic effects and the concentration, size distribution and the chemical composition of the retained particles. Automatic analysis of approximately regularly shaped particles with a computer-controlled scanning electron microscope (CCSEM) was used for this purpose, while the fiber content was determined manually on the SEM-screen. The SEM examination of real and irregularly shaped fibers at a magnification of 6000x resulted in an average concentration that was increased slightly in comparison to that found in so-called normal lungs. Fibers were rather short with a mean length of 3 microns; 95% of the fibers had a length less than 10 microns. There was reasonable agreement between medical findings and mineralogical analyses concerning the grade of pneumoconiosis in most of the cases.