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) gamma-spectrometry. The concentrations range in water sample was 47.6 +/- 5.6-130.8 +/- 6.3, 0.0-23.4 +/- 0.5 and 0-6.4 +/- 2.0 Bq L-1 for K-40, Th-232 and Ra-226 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 K-40, Th-232 and U-238. Cs-137 was also detected in some part of the region in soil samples. The mean concentration of Cs-137 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.