Measurement of 226-Ra, 232-Th, 40-K and 137-Cs concentrations in sediment samples and determination of annual effective dose due to these radionuclides in vicinity of hot springs in Kerman Province

Abstract

Background: Natural and artificial radioactive materials are the most important sources of radiation for human existing in all over the world, thus investigating their radioactivity is of great importance because of their ionizing properties and harmful effects on human health. Therefore, this study was conducted to measure radionuclides concentrations of 226 Ra, 232 Th, 40 K and 137 Cs in sediment samples collected from various hot springs in Kerman province and also determining received annual effective dose. Materials and Methods: Thirteen sediment samples were collected from different hot springs and concentrations of radionuclides in sediment samples were measured via spectrometry method and using HPGe detector. To evaluate radiation hazards caused by these radionuclides, radium equivalent activity, absorbed dose rate in air, and annual effective dose of samples were calculated. Results: Concentrations of 226 Ra, 232 Th, 40 K and 137 Cs in sediment samples varied from 21. 01±0.71 to 193.16±1.72, 16.84±1.21 to 245.92±2.69, 90.13±3.37 to 667.81±14.59 and <MDA to 5.81±0.66 Bqkg -1 , respectively. Also, minimum and maximum values of annual effective dose were determined as 0.17±0.00 and 1.48±0.01 in mSvy -1 , respectively. Conclusion: Comparison of radionuclides concentrations and annual effective dose obtained in this study with the worlds̓ average values determined by UNSCEAR (2000) reports showed that concentrations of 226 Ra and 232 Th in 69% and concentration of 40 K in 46% of measured samples were higher than the worlds̓ average values. Also, annual effective dose of 30% of samples was found to be higher than the worlds̓ average value.