Annual effective dose of naturally occurring radionuclides in soil and sediment

In this study, the natural radioactivity level of soils and sediments due to the usage of fertilizers, particularly phosphate fertilizers, in agricultural lands of the Buyuk Menderes River Basin, Western Turkey, have been determined. A total of 40 soil and sediment samples were collected along the Buyuk Menderes River Basin and analyzed for U-238, Th-232, and K-40 radioisotopes using a high-purity germanium detector. The activity concentrations of U-238, Th-232, and K-40 in soils are in the ranges of 32 +/- 4-93 +/- 13, 11 +/- 2-71 +/- 9, and 353 +/- 14-958 +/- 23 Bq kg(-1), and in sediments they are between 22 +/- 6 and 72 +/- 10, 7.3 +/- 0.6 and 50 +/- 5, and 310 +/- 16 and 633 +/- 25, respectively. In addition, to determine the hazard from natural radioactivity, the external terrestrial gamma dose rate in air (nGy h(-1)) and annual effective dose rate (mSv y(-1)) were calculated and compared with internationally recommended values. In soil samples, the average external terrestrial gamma dose rate in air was found to be 80.2 nGy h(-1) and the average annual effective dose is 0.1 mSv.