Abstract
Airborne dust was selectively sampled in three ferrous foundries. Granulometric fractions were analyzed by using standard methods of industrial hygiene to determine the concentrations of dust, crystalline silica, and metal fumes. Physicochemical techniques such as secondary ion mass spectrometry (SIMS), electron spectroscopy for chemical analysis (ESCA), and electron microscopy were used to probe the heterogeneity of the dust particles. The trend in airborne dust concentrations seemed to be explainable by the extent of natural or mechanical ventilation in the foundries, although the differences between foundries were generally not statistically significant. Quartz was present in large and medium-size particles and absent in small (< 0.5 µm) particles. Lead was always concentrated in the small particle fraction and was preponderant in the foundry where untreated scrap metal was used. Clustering and multivariate analysis of metallic element relative concentrations were consistent with the model of low-boiling-temperature metals covering high-boiling-temperature metals. The complexity in particle composition increased as the average aerodynamic diameter of the particle decreases. The metallic content of small particles was higher than that of large particles and was related to casting operations. Medium-size and large particles seemed to come mainly from the sand and other ingredients used in the molding operations.