The activity concentrations of 226Ra, 232Th, 40K and 137Cs in water and sediment samples from hot springs of Mahallat and soil samples from their neighboring environs have been determined using two high resolution high purity germanium (HPGe) detectors with relative efficiencies 38.5% and 55%. The activity concentrations of 226Ra, 232Th, 40K and 137Cs in sediment samples from hot spring Donbe and Soleymani varied from 1405.90 ± 34.29 to 1630.56 ± 20.84, 26.29 ± 2.26 to 39.99 ± 2.39, 125.40 ± 6.23 to 137.33 ± 7.99 and 3.53 ± 0.53( sediment of Donbe) Bqkg-1 respectively. For soil samples the specific activity of corresponding radionuclides were found to be 12.98 ± 0.46 to 38.03 ± 1.32, 18.15 ± 0.77 to 27.63 ± 1.58, 257.48 ± 13.20 to 359.98 ± 19.49 and 0.11 ± 0.08 to 1.59 ± 0.55 Bqkg-1 respectively. The specific activity of corresponding radionuclides (except 137Cs) in water samples taken from orifice of hot spring Donbe, Shafa and Soleymani varied from 0.90 ± 0.19 to 1.62 ± 0.24, 0.64 ± 0.20 (only Soleymani) and 5.72 ± 1.20 to 13.57 ± 1.07 Bqkg-1 respectively. The average absorbed dose rate due to radionuclides in sediment and soil were estimated to range from 623.52 nGyh-1 to 728.14 nGyh-1and 28.68 nGyh-1 to 50.08 nGyh-1 respectively.
