B.S. GOSHU^#, E. ABASA, MELAKU WOLDEAMANUEL

Department of Physics, Dire Dawa University, Ethiopia

Measurements of natural radioactivity in drinking water have been evaluated in most parts of the world to assess the dose rate and irradiation risk. This work aims to determine the natural radioactivity of bottled drinking water produced in Dire Dawa City and the surrounding area. Natural radioactivity water from nine different brands is produced and commonly sold in bottles. The measurement was done by gamma-ray spectroscopy using a hyper-pure germanium detector. The water specific activity in ²³⁸U ranged from 2.91  0.42 to 4.04  0.42 Bq L^–1; in ²²⁶Th, it ranged from 4.66  2.48 to 13.31  0.2.48 Bq L^–1, and in ⁴⁰K, it ranged from 106  8.71 to 136.52  8.71 Bq L^–1. These results were compared with the reported values from other countries. Annual estimated effective doses from the intake of natural radionuclides in bottled drinking water were found to be below the limit of 0.1 mSv y^–1 recommended by World Health Organization (WHO). The cumulative average annual effective doses of ²³⁸U for different age groups of (0 – 1), (1 – 2), (2 – 7), (7 – 12), (12 – 17) years, and above 17 years were estimated to be 3.01, 0.30, 0.60, 0.90, 2.88, and 0.66 mSv y^–1, respectively.

Key words: radioactivity, specific activity, bottled water, annual effective dose

Corresponding author’s e-mail: belaysitotaw@gmail.com