Risk Assessment from Intake of Naturally Occuring Radioactive Materials in Some Bottled Drinking Water on the Ghanaian Market

Abstract

Activity concentrations of the Naturally Ocurring Radioactive Materials (NORMs) in some bottled water brands were analyzed using gamma spectrometry. 40K activity concentrations were in the range of 3.57-5.47Bq/L, the highest occurring in brand L9. Similarly 232 Th activity concentrations were in the range of 0.30-0.56 Bq/L with the highest occurring in brand L8. 226Ra was identified in eleven brands with the remaining five below detection limit. The highest value (0.53Bq/L) occurred in brand L9. Comparison of the mean concentrations showed significant differences at (α=0.05) between the various brands of bottled water. Estimated committed effective doses were generally below 0.1mSv/a for all age groups with the exception of children <1yr. Estimated lifetime cancer and hereditary risk was done using the ICRP risk assessment methodology. Relationship between Activity concentrations and some physicochemical parameters were established using scatter graphs. The significant one was the conductivity parameter and how estimated activity concentrations tend to correlate (Jobbàgy et al, 2013). Trace elements and heavy metals were analysed using titrimetry, UV-VIS spectroscopy and atomic absorption spectroscopy. Their levels were below recommended and conventional levels. Conclusively bottled water brands analyzed were therefore radiologically safe.