Investigation on natural radiation level and its hazardous nature of river sediments using γ-ray spectroscopy

Abstract

The content of natural radionuclides (238U, 232Th, 40K) in sediment samples of Ponnaiyar River, taken from different depths, were determined using a γ-ray spectroscopic system with a NaI(TI) detector with an aim of evaluating the radiation hazard. The results are compared with Indian and world average values. To know the complete radiological characteristics, the radiological indices such as absorbed dose rate, annual effective dose equivalent (indoor and outdoor), radium equivalent activity, hazard index (H ex and H in), γ-index, activity utilization index, and excess lifetime cancer risk were calculated. The results obtained were discussed and compared with the recommended values. The outdoor γ-dose rates were measured at each sampling site using an environmental radiation dosimeter. The measured results were compared with literature values and correlated with the calculated absorbed dose rate. Averages of all the radiation hazard indices and concentrations of all the measured radionuclides in all the layers are lower than the recommended level. The origin of the detected radionuclides is assessed by comparing the present results with the corresponding values for the earth crust and other rock formations.