Measurements of natural radioactivity concentration in drinking water samples of Shiraz city and springs of the Fars province, Iran, and dose estimation

The Fars province is located in the south-west region of Iran where different nuclear sites has been established, such as Bushehr Nuclear Power Plant. In this research, 92 water samples from the water supplies of Shiraz city and springs of the Fars province were investigated with regard to the concentrations of natural radioactive elements, total uranium, Ra-226, gross alpha and gross beta. Ra-226 concentration was determined by the Rn-222 emanation method. To measure the total uranium concentration, a laser flourimetry analyzer (UA-3) was used. The mean concentration of Ra-226 in Shirazs water resources was 23.9 mBq l(1), while 93 of spring waters have a concentration 2 mBq l(1). The results of uranium concentration measurements show the mean concentrations of 7.6 and 6 g l(1) in the water of Shiraz and springs of Fars, respectively. The gross alpha and beta concentrations measured by the evaporation method were lower than the limit of detection of the measuring instruments used in this survey. The mean annual effective doses of infants, children and adults from U-238 and Ra-226 content of Shirazs water and spring waters were estimated. According to the results of this study, the activity concentration in water samples were below the maximum permissible concentrations determined by the World Health Organization and the US Environmental Protection Agency. Finally, the correlation between Ra-226 and total U activity concentrations and geochemical properties of water samples, i.e. pH, total dissolve solids and SO42, were estimated.