Evaluation of the Solubility of Be-7 Particles in Simulated Lung Fluid

During preparations for an experiment to be conducted in the Soreq Applied Research Accelerator Facility (SARAF) at Soreq Nuclear Research Center, a target containing approximately 10 GBq of ⁷Be was damaged releasing particles into the room that subsequently were inhaled by a small group of workers (Aviv et al., 2017). Removal of inhaled particles was studied in one of the exposed workers by performing a series of direct (in vivo) and indirect (urinalysis) bioassay measurements over time. Results of the in vivo measurements over a period of 108 days demonstrate that retention of ⁷Be in the respiratory tract can be described using a two-component exponential function with half-lives of ~0.4 days and ~109 days. Information provided by the target manufacturer (Maugeri et al., 2017) suggests that the particles in the source are beryllium hydroxide (Be(OH)₂), which is only slightly soluble in water. However, results of direct, in vivo measurements suggest that most of the activity was rapidly removed from the respiratory tract. Samples of ⁷Be particles swiped from the damaged target were dissolved in simulated lung fluid and measured over time using an HPGe detector to evaluate solubility in vitro. Rapid (< 1 day) dissolution of the ⁷Be particles measured in vitro is consistent with rapid removal from the respiratory tract as measured in vivo. The methods used for determining the solubility will be presented, as well as detailed results.