Differences in dissolution behavior in a phagolysosomal simulant fluid for single-component and multi-component beryllium materials associated with beryllium sensitization and chronic beryllium disease.
Stefaniak A; Day G; Hoover M; Breysse P; Scripsick R
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California. Fairfax, VA: American Industrial Hygiene Association, 2005 May; :66
Dissolved beryllium is the hypothesized input to the cell-mediated immune reaction associated with development of beryllium sensitization and chronic beryllium disease (CBD). Particle dissolution within the macrophage phagolysosome is thought to be an important source of dissolved beryllium. Using a phagolysosomal simulant fluid (PSF) in a static dissolution technique, we measured dissolution rates for single- and multi-component beryllium aerosol materials associated with elevated prevalence of beryllium sensitization and CBD. The observed dissolution rates were normalized to measured values of specific surface area (SSA) to calculate a chemical dissolution rate constant (k) for each material. The values of k, in g/(cm2·day), for single-component beryllium oxide released from a screener unit operation (1.3 +/- 1.9 x 10-8) and for single-component finished product beryllium oxide powder (1.1 +/- 0.5 x 10-8) were similar (p = 0.45). The value of k observed for single-component finished product beryllium metal powder (1.1 +/- 1.4 x 10-7) was significantly greater than observed for the beryllium oxide materials (p<0.0003). For multi-component aerosol material collected from an arc furnace during processing of copper-beryllium alloy, k (1.6 +/- 0.6 x 10-7) was significantly greater than observed for single-component beryllium oxide (p<0.00001), despite the fact that the chemical form of beryllium in the aerosol was beryllium oxide. Thus, knowledge of the SSA of the particles and the k value of the chemical form of beryllium was not sufficient to characterize beryllium dissolution from the multi-component material. Additional studies of the dissolution behavior of beryllium alloy materials, as well as beryllium minerals, metal, oxide, and composite materials in a variety of mixture configurations (uniform mixtures, nonhomogeneous mixtures, surface coatings, etc.) are needed to aid in developing exposure - response models to improve understanding of the risk of beryllium sensitization and CBD.
Beryllium-compounds; Sensitization; Beryllium-disease; Diseases; Aerosols; Aerosol-particles; Models; Risk-analysis; Risk-factors; Respiratory-system-disorders; Pulmonary-system-disorders
7440-41-7; 1304-56-9; 7440-50-8; 1317-39-1
Research Tools and Approaches: Exposure Assessment Methods
American Industrial Hygiene Conference and Exposition, May 21-26, 2005, Anaheim, California