Activity concentration of terrestrial and anthropogenic radionuclides (²²⁶Ra, ²²²Rn, ²³²Th, ⁴⁰K, and ¹³⁷Cs) in soil samples

Measurement of the activity concentrations of terrestrial and anthropogenic radionuclides in one hundred fifteen soil samples collected from various locations in Samsun city was taken using a gamma-ray spectrometer with a NaI (Tl) detector. The average activity concentrations of terrestrial radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K were measured as 38.1 ± 1.4, 39.3 ± 0.8, and 375.3 ± 10.2 Bq kg⁻¹, respectively. The average activity concentration of anthropogenic radionuclide ¹³⁷Cs measured in some soil samples was found as 12.1 ± 0.7 Bq kg⁻¹. Radon concentrations in soil and in air were estimated using results of the measurement of activity concentrations of ²²⁶Ra. The average concentrations of radon in soil and air were found as 32 kBq m⁻³ and 101 Bq m⁻³, respectively. The absorbed gamma dose rate in outdoor air due to terrestrial radionuclides in soil samples varied from 28 to 95 nGy h⁻¹ with an average of 57 nGy h⁻¹. The annual effective dose rates caused from external and inhalation exposure were estimated as 70 and 958 μSv y⁻¹, respectively.