Arc Welders’ Pneumoconiosis: Application of Advanced Scanning Electron Microscopy

Abstract

Study of lung tissue from necropsy of a 58-year-old arc welder with arc welders' pneumoconiosis, confirmed by history, chest radiography, and pathology, demonstrates the versatility and usefulness of new techniques in scanning electron microscopy (SEM). Secondary electron imaging, the most familiar SEM mode, showed heavy cellular infiltrates in alveoli, the interstitium, and within the interstices of loose whorled fibrotic nodules. Backscattered electron imaging, in which contrast is proportional to elemental atomic number, revealed intracellular metal particles not otherwise visible. Microprobe analysis, energy-dispersive x-ray spectrometry, mapped elemeental iron over the particle image and identified traces of silicon in the whorled nodules. Arc welders' pneumoconiosis appears to be more than a benign siderosis resulting from particulate iron deposition. Simultaneous exposure to other components of welding fumes may alter the pathologic picture, inducing a more complicated fibrotic reaction. The more recently developed advanced techniques of SEM are well suited to the study of pneumoconioses and other problems of heterogenous tissue and mixed chemical systems.

Role of metal oxide nanoparticles in histopathological changes observed in the lung of welders

“…However, although using the valuable combined (S)TEM/EDX analysis as developed by Abraham and colleagues [23-26], these studies present some major limitations, such as a small number of patient(s) [19,21], or a very specific exposure (aluminum factory, not representative of the general occupational exposure of welders) [20]. Our study in the other hand is the first to provide persuasive evidence not only of the presence of NP in situ in human lung tissue samples, but also the identification of their chemical composition.…”

Welders' pneumoconiosis: tissue elemental microanalysis by energy dispersive x ray analysis.

“…8 They also used a high magnification (2000 x ) and analysed particles seen inside the individual cells and found them to contain iron and silicon. Both Stettler et al and Guidotti et al emphasised the usefulness of in situ microanalysis of small particles seen in the lung tissue.17 18 We have used a similar technique to analyse black particles seen in cases of pulmonary interstitial fibrosis, and found that these particles contain chromium, iron, cobalt, and nickel. '4 In the present study we used a lower magnification that allowed us to cover a larger area for analysis.…”

Pulmonary effects of welding fumes: Review of worker and experimental animal studies

“…There are reports of welders who have experienced Xray abnormalities and extensive fibrosis [Liss, 1996]. These have often resulted from non-welding inhalation exposures of mixed-dusts (i.e., silica, asbestos, and coal dust) encountered in the welder's working area [Morgan, 1962;Guidotti et al, 1978]. However, high fume exposure levels and improper ventilation in the welder's working area also may lead to debilitating chronic lung disease.…”