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, (226)Ra, gross alpha and gross beta. (226)Ra concentration was determined by the (222)Rn emanation method. To measure the total uranium concentration, a laser fluorimetry analyzer (UA-3) was used. The mean concentration of (226)Ra in Shiraz's 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 μg 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 (238)U and (226)Ra content of Shiraz's 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 (226)Ra and total U activity concentrations and geochemical properties of water samples, i.e. pH, total dissolve solids and SO4(-2), were estimated.