Revisiting methods for the assessment of naturally-occurring radioactivity in drinking water

Abstract

A comprehensive radioactivity characterisation of Castilla y León (Spain) groundwater intakes intended for human consumption is addressed between 2017 and 2021. This study responds to the radiological requirements stated in the European Council Directive 51/2013/EURATOM concerning drinking water for public health. Given that the gross α- and gross β-activity determination is used as a screening strategy for water radioactivity monitoring, the reliability of the thin-source deposit method (ISO 10704, 2019) has been improved to achieve representative values of the total activity coming from α- and β-particle emitters in the samples. More than 400 groundwater samples have been considered for this purpose, analysing their 238,235,234U, 228,226Ra, 210Pb, and 210Po activity concentrations, which are needed for the indicative dose assessment. These results, considered reference activity values, are compared with the gross α- and gross β-activities determined by the different procedure approaches. Ultimately, the results of the liquid scintillation counting method (ISO 11704, 2018) are also used to validate the optimised method.