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

Activity concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K 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 ²²⁶ Ra 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 ²³² Th, 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 ⁴⁰ K, 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 ²²⁶ Ra and ⁴⁰ K, whereas drinking water showed the highest ²³² Th 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 ²²⁶ Ra shows statistical significance, whereas ²³² Th and ⁴⁰ K are the opposite; ²²⁶ Ra shows greater heterogeneity.