Radon exhalation and transfer processes in aqueous media

Abstract

The present work gives a proof-of-concept for the complex factors that affect radon-in-water measurements through its progeny activities. Mathematical model was formulated, and an experiment was performed on a solution containing thorium and uranium series to identify the conditions for radon-in-water transfer. The experiment was performed on a solution containing thorium and uranium series at pH 5.5, isolated for 2 y, just measured before and repeatedly after exposing its surface to the ambient atmosphere. The measurement setup was carefully designed to avoid turbulence in consequence to rise velocity of these gaseous bubbles. During isolation time, radon found to accumulate in voids within the soft medium of water, and radon progeny may be re-dissolved in the medium in a non-homogenous manner that depends on the properties and geometry of the soft solution and existence of carrier gases such as emanating helium and water vapor. The rate of radon exhalation from the surface of the liquid was determined. The present results threw doubt on the activities measured assuming equilibrium between radon concentration and its progeny due to its dependence on geometry and ambient conditions.