Characterization by Scanning Transmission Electron Microscopy of Silica Particles from Alveolar Macrophages of Coal Miners

The structure and composition of silica-rich particles recovered by lavage from the lungs of three active miners with different medical histories were studied using high-resolution electron microscopy and chemical microanalysis. The results are compared to the similarly determined structure and composition of respirable-size mineral particles obtained from roof-bolter dust-box samples from two coal mines of widely different bulk quartz concentrations. The results show that the lungs of the miners contain silica-based particles with structures not found in the mine samples. Also, the particle structures and compositions found in the macrophages were different in each of the miners. The results suggest the possibility that intracellular processes may affect the susceptibility of individuals to silica-induced pneumoconioses.