Generation and Characterization of Respirable Beryllium Oxide Aerosols for Toxicity Studies

Abstract

Methods are described to produce respirable particles of ⁷Be-labeled beryllium oxide at temperature treatments of up to 1000°C for use in toxicity studies. Solutions of beryllium oxalate and suspensions of beryllium hydroxide were nebulized to produce polydisperse particles with activity median aerodynamic diameters in the range of 0.5–0.7 μm and geometric standard deviations between 2.7 and 3.0. Conversion to beryllium oxide was incomplete when the nebulized particles were passed through a tube furnace at temperatures up to 1000° C. Complete conversion was achieved by calcining samples of the collected particles in a muffle furnace for 16 hours at 500 or 1000°C. Particles produced by nebulizing and heat-treating the beryllium chloride or oxalate solutions were hollow shells, but particles nebulized from beryllium hydroxide suspensions were aggregates morphologically similar to industrially produced beryllium oxide particles.