Department of Physics, Faculty of Science, Arak University, Arak 38156, Iran
The activity concentrations of 235U, 232Th, 226Ra, 40K and 137Cs in ground and surface of drinking water resources in Iranian city of Arak were determined by gamma ray spectrometry with aHPGe detector setup, coaxial p type and 8192 channels MCA. The water samples differed in radioactivity content depending on their origin and place. In the drinking water samples from Aman Abad, Mobarak Abad, and Taramazd wells, the mean values of 226Ra activity concentration were 8.43±1.96, 1.56 ±1.04, 1.29±1.07 and 2.20±0.10 Bq/l and the mean values of 232Th were 2.70± 0.18, 0.41±0.16 and 1.27±0.44 Bq/l, respectively. The maximum and minimum activity concentrations of 232Th belong to Amman Abad area wells No. 7 and Mobarak Abad area wells No. 3, respectively. In Kamal Saleh water, the results of activity concentrations show 0.33 ± 0.14 and 0.08±0.03 Bq/l for 232Th and 137Cs, respectively. The other radionuclide activities were lower than MDA. A mean annual effective dose for 232Th and 226Ra taken into the body by population drinking water for Kamal Saleh dam water and Aman Abad well No. 14 was calculated to be 0.01 ±0.00 and 1.84±0.17 mSv/year respectively, which is lower than the limit recommended by WHO.