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Arc welders' pneumoconiosis: studies with advanced techniques of scanning electron microscopy and microprobe analysis.

Guidotti-TL; Abraham-JL; DeNee-PB; Smith-JR
Fifth International Pneumoconiosis Conference, 29 November, 1978, Caracas, Venezuela, International Labour Organization 1985; :733-745
Techniques for use in studying pneumoconiosis among arc welders were developed and tested. Lung tissues obtained via necropsy were fixed in a buffered 10 percent formalin solution, with blocks being embedded in paraffin. Sections were stained, then examined by light microscopy. Tissues were prepared for scanning electron microscopy (SEM) using standard methods. Lung tissues were also studied via microbeam or microprobe analysis (MPA), which consists of the spectrophotometric detection of the electromagnetic energy released in the X-ray wavelength by the bombardment of a target with electrons. Large particles approximately 14 micrometers in diameter and not visible in secondary electron (SE) images were clearly identified within the lung tissue cells analyzed. Iron was detected in the alveolar macrophages, but was only present in the interstitium in trace amounts. Backscattered electron (BSE) imaging revealed the presence of particles in the distal parts of the pseudopods, shown by MPA to contain iron. Other macrophages in the fibrotic plaque, as well as in the fibrous stroma, contained traces of silicon. The authors conclude that these SEM and MPA techniques are capable of locating the particles contained in cells, as well as of identifying the elemental compositions of these particles. SE imaging provides information concerning surface features and morphology and identifies intracellular particles that cannot be seen by SE imaging. The MPA technique constitutes a convenient and non destructive method for use in elemental analysis, allowing elemental distributions to be mapped over visual images.
Laboratory-techniques; Lung-tissue; Analytical-methods; Microscopic-analysis; Electronic-equipment; Occupational-hazards; Occupational-exposure; Welding-industry; Trace-analysis;
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Fifth International Pneumoconiosis Conference, 29 November, 1978, Caracas, Venezuela, International Labour Organization
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division