Radioactivity in Bottled Drinking Water from Greater Dhaka City and Concomitant Ingestion Doses to Consumers

Activity concentrations of 226Ra, 232Th, and 40K radionuclides were determined in various brands of bottled drinking water commonly available in the local markets of Greater Dhaka City; additionally, the annual effective dose following the ingestion pathway was assessed. Radioactivity of 226Ra in the bottled water (purified, mineral, and drinking) samples varied from 0.61 ± 0.27 Bq L-1 to 10.64 ± 1.34 Bq L-1 with a mean value of 4.73 ± 1.02 Bq L-1. For 232Th, the concentration ranged between 0.35 ± 0.27 Bq L-1 and 5.71 ± 3.37 Bq L-1 with a mean of 2.97 ± 1.61 Bq L-1; for 40K, it ranged from 3.48 ± 2.92 Bq L-1 to 93.58 ± 26.74 Bq L-1 with a mean of 36.31 ± 10.63 Bq L-1. Purified bottled water exhibited the highest activity concentrations of 226Ra and 40K, whereas drinking water showed the highest 232Th concentration compared to purified and mineral bottled water samples. Infants received higher annual ingestion doses compared to children and adults. The average value of the threshold consumption rate remained below the limit. The 226Ra shows statistical significance, whereas 232Th and 40K are the opposite; 226Ra shows greater heterogeneity.