Dose rates and seasonal variations of 238 U, 232 Th, 226 Ra 40 K and 137 Cs radionuclides in soils along Thrace, Turkey

Concentrations of 238 U, 232 Th, 226 Ra, 40 K and 137 Cs are measured in collected soil samples from various locations in the Thrace region of Turkey. The activity concentrations range from 12.82 to 101.75 Bq kg −1 d.w. (dry weight) for 238 U, from 5.16 to 73.34 Bq kg −1 d.w. for 232 Th, from 185.54 to 5399 Bq kg −1 d.w. for 40 K and from 11.42 to 90.73 Bq kg −1 d.w. for 226 Ra. In addition to naturally occurring radionuclides, 137 Cs activity concentration is determined between 3.05 and 46.78 Bq kg −1 d.w. for soil samples. Determination of the radiological hazard is achieved through calculations of the external terrestrial gamma dose rate in air (nGy h −1 ) and annual effective dose rate (mSv year −1 ) and the results are compared with the similar works in different countries.