Abstract
To aid in the toxicologic evaluation of solvent refined coal (SRC) materials, we developed an aerosol generation system for whole-body inhalation exposure of experimental animals to coal liquids. The main components of the exposure system were an aerosol generator, a manifold for delivery of the aerosol, three exposure chambers and an exhaust system. High-boiling coal liquids from the SRC-I and SRC-II processes were used as test materials. Aerosol concentrations were measured by drawing aerosol samples from the chamber through a Metricel filter and eluting the coal liquid into chloroform. Since these coal liquids have an ultraviolet absorption peak at 254 nm, the absorbance was determined at this wavelength. As part of the experiment, we evaluated the Solo-Sphere,® Retec® and Collison neubulizer as aerosol generators for the coal liquids. Both the Solo-Sphere and Retec provided adequate concentrations of respirable particles; however, aerosol concentrations within the exposure chamber were more consistent with the Solo-Sphere. Low mass output and plugging were encountered with the Collison. Use of the Solo-Sphere generator and manifold delivery system resulted in consistent and uniform aerosol concentrations and particle sizes in the exposure chamber over a 15-day test period. Analysis of the chamber atmosphere when SRC-I process solvent was used indicated the presence of vapors as well as particles. The ultraviolet absorption spectrum suggested that two-ring polynuclear aromatic compounds were the major constituents of the vapor phase.