Gross alpha/beta activity concentrations in imported bottled drinking water in Saudi Arabia

Abstract

This research assessed the gross alpha and beta activity levels in bottled drinking water imported to Saudi Arabia, applying the evaluation process recommended by the World Health Organization (WHO). The WHO's approach for examining alpha and beta activity in drinking water consists of an initial phase of screening for gross alpha and beta levels to determine the need for further analysis. This is followed by a detailed assessment of specific radionuclide concentrations if initial screening levels are surpassed. The study utilized the evaporation method as a standard procedure to quantify the gross alpha and beta activity levels. Each water sample underwent evaporation, after which the activity levels of the residual matter were measured. Gross alpha activity was analyzed using a ZnS (Ag) scintillator detector system, while gross beta activity levels were gauged using a proportional counting system. The methodologies for determining gross alpha and beta activities align with the International Organization for Standardization (ISO) standards ISO 9696 and ISO 9697, respectively. The research identified the maximum alpha and beta activity levels to be 0.18 Bq/L and 0.34 Bq/L, respectively. These values were evaluated against the WHO guidance threshold values of 0.5 Bq/L for gross alpha and 1.0 Bq/L for gross beta activities, confirming that the exposure remains below the individual dose criterion of 0.1mSv/year. The estimated committed effective doses fell under the WHO's advised cap of 0.1 mSv annually, indicating the safety of the water samples for consumption. The study recommends the analysis of a larger set of samples over extended periods for increased assurance.