Activity concentration of natural radionuclides in sediments of Bree, Klein-Brak, Bakens, and uMngeni rivers and their associated radiation hazard indices

A hyper-pure germanium (HPGe) detector was used to measure the activity concentrations in sediment samples of rivers in South Africa, and the associated radiological hazard indices were evaluated. The results of the study indicated that the mean activity concentrations of 226Ra, 232Th and 40K in the sediment samples from the oil-rich areas are 11.13, 7.57, 22.5 ; 5.51, 4.62, 125.02 and 7.60, 5.32, 24.12 for the Bree, Klein-Brak and Bakens Rivers, respectively. In contrast, the control site (UMngeni River) values were 4.13, 3.28, and 13.04 for 226Ra, 232Th, and 40K. The average excess lifetime cancer risks are 0.394 × , 0.393 × , 0.277 × and 0.163 × for sediment samples at Bree, Klein-Brak, Bakens, and uMngeni rivers. All obtained values indicated a significant difference between the natural radionuclide concentrations in the samples from the rivers in oil-rich areas compared to those of the non-oil-rich area. The values reported for the activity concentrations and radiological hazard indices were below the average world values; hence, the risk of radiation health hazard was negligible in all study areas.