major contribution to the public exposure on Earth has the natural radioactive element Radon (Rn- 222). There is a risk of developing cancer from long term exposure to radon in air and water. The inhalation of radon, a well-established human carcinogen, is the principal source of radioactivity exposure for the general population of most countries. The water used for drinking and other household uses can increase the indoor radon level, because dissolved radon escapes from the water and gets into household air in the course of dishwashing, showering, and other water-using activities. Also, ingesting water with elevated levels of radon can present a risk for developing internal organ cancers. In this study radon and radium concentrations of the 77 water samples have been measured by PRASSI system. 7 samples have radon concentration higher than 11 Bq/l as normal level. Similarly, the annual effective dose in stomach and lung per person has been evaluated in this research. According to the advice of WHO and EU Council, just 2 samples induced

Keywords