Nonfibrous mineral particles in bronchoalveolar lavage fluid and lung parenchyma from the general population

It is recognized that bronchoalveolar lavage (BAL) gives access to particulate matter present at the surface of the peripheral airspace. The objective of the present study was to evaluate the ability of BAL fluid analysis to predict the lung parenchymal particulate content. A BAL fluid sample, the parenchyma sample having undergone BAL, and an adjacent parenchyma sample that had not undergone BAL were obtained at autopsy on 10 individuals without any known recent occupational exposure to mineral particles. The particles (larger than 0.1 micron) were analyzed using a transmission electron microscope equipped with a microanalysis system. Nineteen types of particles were distinguished. The distribution of particle types in the three samples was compared. No significant difference between the relative concentrations was found, except for two particle types: fly ash (excess in BAL fluid compared with lavaged lung) and kaolinite (excess in lavaged lung compared with adjacent area). Such differences may be due to limitations in methodology. Although no correlation could be found between the absolute concentrations of particles in BAL fluid and in lung tissue, analysis of particles in BAL fluid may provide information on the types of particles present in the lung parenchyma.