Assessment of geogenic natural radionuclide contents of soil samples collected from Ogun State, South western, Nigeria

Background: Natural radionuclides are always present in the environment. Human exposure to the background radiaon is inevitable. It is therefore important to assess health risk associated with these radionuclides. Materials and Methods: The distribuon of natural radionuclides 238U, 232Th and 40K in soil samples collected from all the twenty (20) local Governments headquarter areas in Ogun state, Nigeria were determined by gamma spectroscopy using a high-purity germanium detector. The measured concentraons were used in esmang the radiological risk pose to people living in these communies. Results: The acvity concentraons measured ranged between 3 ± 1 Bqkg-1(O0a) to 27 ± 6 Bqkg-1(odeda) for 238U, 10 ± 1 Bqkg-1(O0a) to 126 ± 6 Bqkg-1(Ijebu Igbo) for 232Th and 7 ± 6 Bqkg-1(Aiyetoro) to 497 ± 1 Bqkg-1(Odeda) for 40K. The mean radium equivalent calculated was 77.6 Bqkg-1 which is lower than 370 Bqkg-1 of the world average and the hazard indices calculated were lower than unity. Conclusion: The absorbed rate and annual effecve dose esmated for most of the locaons are in good agreement with world average values except for Akomoje, Ake-Abeokuta, Ogere, Ijebu-Igbo and Odeda.