Measurement of 222-Rn concentration levels in drinking water samples from Qena city (Egypt) and evaluation of the annual effective doses

Background: Radon is one of the most important radionuclides, formed from the decay of the element radium and more soluble in water. As drinking water is a vital source of life, control of its quality is critical. Drinking water containing high radon levels presents a serious risk to human health. Thus awareness of radon levels in drinking water is extremely significant to protect against radiation exposure. We measured Rn concentrations in different types of drinking water from Qena city, Egypt. Materials and Methods: 111 water samples were collected from various sources in Qena city (77 samples of household tap water, 14 samples of bottled water and 20 samples from municipal public water supply locations). The Rn concentrations were determined using an AlphaGUARD radon gas analyzer. We calculated annual effective dose due to ingestion and inhalation of Rn present in these waters. Results: Rn concentration ranges were as follow: 22.0±0.7 to 118±3 mBq l, from tap water 14±3 to 237±5 mBq l from bottled water and 6.0±0.5 to 30.0±0.9 mBq l from municipal public supplies. The annual effective dose due to inhalation and ingestion of Rn in all types of drinking water measures less than the recommended reference level of 100 μSv y. Conclusion: Based on the obtained results, Rn concentrations in the studied water samples were less than the permitted concentrations of USEPA and WHO guidelines.