Determination of aquatic radon by liquid scintillation counting and airborne radon monitoring system

This paper presents an airborne radon monitoring (RM) system for aquatic radon determination after out-gassing of radon from the aqueous sample and compares this method with the standard ASTM method for radon analysis in aquatic samples, e.g. liquid scintillation counting (LSC) after extraction of radon by a scintillation cocktail. Calibration of the method shows good linearity, high efficiency (100%) and detection limits better than 0.1 Bq/l, indicating that the method is suitable for low-level radon determination in aquatic samples. Moreover, because RM is less time and material (e.g. LSC cocktail and vials) consuming it could be more attractive for routine measurements. Application of the two methods to natural aquatic samples results in almost similar radon concentrations (90% correlation) and shows that radon levels in Cypriot groundwaters vary from 0.1 to 15 Bq/l, depending strongly on the geological background.