Evaluation and mapping of radioactivity and radiological risks in sediments before the nuclear power plant in Türkiye

The main aim of this study was to investigated background levels of radioisotopes 137Cs (Cesium), 232Th (Thorium), 40K (Potassium), and 226Ra (Radium) in all samples taken from two important rivers of the Sinop province prior to the nuclear power plant. The sediment samples were taken from the Karasu (80 km) and Kabali (51.3 km) rivers at 2 km distances in July 2019, the month with the least precipitation, and in December 2018, the month with the most precipitation, before the nuclear power plant built in the Sinop province became active. The concentrations of 226Ra, 232Th, 137Cs and 40K in the collected sediment samples were measured using a high purity germanium detector (HPGe). The activity concentrations of 226Ra, 232Th, 137Cs and 40K in the sediment samples taken from the Karasu River in December and in July were in the range of 3.08-29.40 Bq/kg, 2.95-19.10 Bq/kg, 0.35-61.13 Bq/kg and 54.83-495.02 Bq/kg, respectively. In the sediment samples collected from the Kabali River in December and in July, 226Ra, 232Th, 137Cs and 40K activity concentrations were in the range of 5.79-25.65 Bq/kg, 3.35-19.55 Bq/kg, 0.97-7.23 Bq/kg and 141.66-446.77 Bq/kg, respectively. Some risk parameters were also calculated to assess radiological hazards. These values were found to be lower than the world averages recommended by international organizations. Based on all the results obtained, it can be concluded that the examined samples do not pose a radiological risk.