Radiological hazard assessment of natural radioactivity in Avcilar region, Turkey: a case of Istanbul University-Cerrahpasa Avcilar Campus.

Radionuclides ²²⁶ Ra, ²³² Th, and ⁴⁰ K can be found in various concentrations in the surface soil. High concentrations of radionuclides in the surface soil may cause radiological risks. This study investigated natural radioactivity levels and artificial radionuclide ( ¹³⁷ Cs) levels in the Istanbul University-Cerrahpasa, Avcilar region, Istanbul, Turkey. Radioactivity concentrations were analyzed using the gamma-ray spectrometer. The mean activity concentration of ²²⁶ Ra, ²³² Th, ⁴⁰ K, and ¹³⁷ Cs is 28.55, 29.57, 385.72, and 3.09 Bq kg ^-1 , respectively. Radiological parameters radium equivalent activity, absorbed dose rate, annual effective dose equivalent, external hazard index, and excess lifetime cancer risk were calculated using activity concentrations. The radiological parameters values were lower than UNSCEAR values, except for the annual gonadal dose equivalent (approximately 10% higher). There is a strong correlation between radiological parameters and radionuclides. Generally, the activities of radionuclides in the region fall within the recommended limits, thus Istanbul-Avcilar region can be considered safe for settlement.