Abstract Introduction Natural and artificial radionuclides are the main sources of human radiation exposure. These radionuclides, which are present in the environment, can enter to the water. Radionuclides by drinking water or consumed as hot spring entering the human body can be harmful on human health. Materials and Methods Ten samples from ground water of Arak resource, one samples of surface water (Kamal Saleh Dam) and four samples from hot springs of Mahallat of Iran were collected. Specific activities of 226Ra, 232Th, 40K and 137Cs were determined in the samples, using gamma ray spectrometry method and a high-purity germanium (HPGe) detector. Results Specific activities of 226Ra, 232Th, 40K and 137Cs were determined in water samples. In drinking water taken from Aman Abad, Mobarak Abad, and Taramazd wells, the mean values of 226Ra activity concentration were 7.65± 1.64, 1.56 ±1.04 and 1.45±1.39 Bq/l and mean values of 232Th were 2.70± 0.18, 0.41±0.16 and 1.27±0.44 Bq/l respectively The annual effective dose due to drinking water varied from 0.01 to 0.78 mSv/y. The specific activity of corresponding radionuclides (except 137Cs) in water samples taken from orifice of hot springs Donbe, Shafa and Soleymani varied from 0.90±0.19 to1.62±0.24, 0.64±0.20 (only Soleymani) and 5.72±1.20 to 13.57±1.07 Bqkg respectively. Conclusion The calculated annual effective dose due to water consumption by Iranians was within the average annual global range. Therefore, this study indicated that radionuclide intake due to water consumption had no consequence for public health. For hot springs in bath rooms should used air condition instrument.
