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 la vage from the lungs of three active miners with different medical hist ories were studied using high-resolution electron microscopy and chemi cal micro-analysis. The results are compared to the similarly determin ed structure and composition of respirable-size mineral particles obta ined from roof-bolter dust-box samples from two coal mines of widely d ifferent bulk quartz concentrations. The results show that the lungs o f the miners contain silica-based particles with structures not found in the mine samples. Also, the particle structures and compositions fo und in the macrophages were different in each of the miners. The resul ts suggest the possibility that intracellular processes may affect the susceptibility of individuals to silica-induced pneumoconioses.