Distribution of terrestrial and anthropogenic radionuclides in Turkish surface soil samples

A comprehensive study was executed to determine the distribution of the natural and anthropogenic radionuclides in surface soils throughout Turkey. In this study, the activity concentrations of 238U, 232Th, 40K and 137Cs in total of 1031 soil samples collected from seven geographical regions of Turkey were measured using the high-resolution gamma spectrometer with HPGe detector. The activity concentrations of 238U, 232Th, 40K and 137Cs in soil samples varied from 2.0 to 220.0 Bq kg− 1 with a mean of 28.6 ± 0.7 Bq kg− 1, 1.0 to 158.6 Bq kg− 1 with a mean of 33.0 ± 0.7 Bq kg− 1, 26.0 to 1603.2 Bq kg− 1 with a mean of 448.5 ± 7.3 Bq kg− 1 and 1.0 to 357.0 Bq kg− 1 with a mean of 13.4 ± 0.8 Bq kg− 1, respectively. Elemental concentration mean values of 238U, 232Th and 40K were found as 2.3 mg kg− 1, 8.1 mg kg− 1 and 1.4%, respectively. For all surface soil samples the absorbed gamma dose rate and the corresponding effective dose rate due to the external exposure in outdoor were evaluated as 51.9 nGy h− 1 (4.7–234.3 nGy h− 1) and 0.064 mSv y− 1 (0.006–0.287 mSv y− 1), respectively.