Assessment of Public dose due to Natural Radioactivity in Drinking Water

Water is essential for the survival of all organisms, including humans; hence the need for adequate safe water cannot be overemphasized. The rise of human internal exposure through inhalation and ingestion are link to the existence of radionuclides in the water bodies. In this study public dose due to natural radioactivity in drinking has been assessed using a low Gas - less Automatic Imatic gross alpha / beta counter system and non-destructive gamma spectrometry system. Samples of ten different brands of Sachet and Bottled natural mineral waters that were most patronized were purchased at various vendor in the Kwabenya community of Greater Accra region employing simple random sampling technique and transported to RPI, GAEC Food and environmental monitoring laboratories for analysis. The average value for activity concentrations for gross alpha and gross beta for the ten different brands drinking water were 2.80 ±1.05mBq/L and 33.30 ± 12.23mBq/L for sachet water and 3.20 ± 2.05mBq/L and 30.60 ± 12.23mBq/L for bottled Natural mineral water respectively. Average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the water samples were 0.4±0.2 Bq/L, 0.8±0.2 Bq/L and 11.6±8.3Bq/L respectively with an estimated average committed effective dose 0.05mSv/yr. Average gross alpha and gross beta activities in samples were below the recommended guidance level set by World Health Organization and Ghana Standard Authority which is 0.5Bq/L, and 1.0Bq/L. The average estimated activity concentrations of ²²⁶Ra and ²³²Th and committed effective dose obtained in this study were found below the WHO recommended guidance level and Individual Dose Criterion of 0.1mSv/yr. It was concluded from the study that the selected sachet/bottled drinking water purchased in Kwabenya is radiological safe and pose no significant hazard to the public. (Author)