Natural and artificial radioactivity measurements in Eastern Black Sea region of Turkey

In the present work, naturally occurring radionuclides of 226Ra, 232Th and 40K were measured in soil samples collected from the Eastern Black Sea region of Turkey. It was found that the activity concentrations ranged from 12 to 120 Bq kg−1 for 226Ra, from 13 to 121 Bq kg−1 for 232Th and from 204 to 1295 Bq kg−1 for 40K. Besides naturally occurring radionuclides, 137Cs activity concentration was measured in soil, lichen and moss samples and it was found that 137Cs activity concentration ranged from 27 to 775 Bq kg−1 with for soil, from 29 to 879 Bq kg−1 for lichen and from 67 to 1396 Bq kg−1 for moss samples. Annual effective doses due to the naturally occurring radionuclides and 137Cs were estimated. Ecological half-lives of 137Cs in lichen and moss species were estimated. The decrease of the activity concentrations in the present measurements (2007) relative to those in 1993 indicated ecological half-lives between 1.36 and 2.96 years for lichen and between 1.35 and 2.85 years for moss species.