Study of natural radionuclides in Karun river region

In this study the concentration of natural radionuclides has been investigated in soil and water of Karun river by using a high resolution (HPGe detector, n-type) ?-spectrometry. The concentrations range in water sample was 47.6 ± 5.6-130.8 ± 6.36.3, 0.0-23.4 ± 0.5 and 0-6.4 ± 2.0 Bq L-1 for 40K, 232Th and 226Ra respectively. For soil samples the concentration range of 275.7 ± 8.6-458.6 ± 6.8, 19.2 ± 5.35-41.1 ± 3.95 and 29.9 ± 1.53-50 ± 1.54 Bq kg-1 was obtained respectively for 40K, 232Th and 238U. 137Cs was also detected in some part of the region in soil samples. The mean concentration of 137Cs was 5.5 ± 0.6 Bq kg-1. The origin of this activity is unknown. The average absorbed dose rate in outdoor air at a height of 1 m above the ground was found to be 54.3 ± 3.7 nGy h-1. The results of this study indicate that the area has standard background radiation level. (author)