Assessment of Background Gamma Radiation and Development of Radiation Contour Map for Kogi Central District, Kogi State, Nigeria

Environmental radiation measurement was carried out in Kogi Central Senatorial District of Kogi State, Nigeria. An in-situ measurement approach was adopted using GCA-O6W, Digital Geiger counter and a handheld Global Positioning System equipment. A total of 101 locations were surveyed across the district. In Adavi Local Government Area, the dose rate ranges from 0.04 µSv/h at Iruvucheba to 0.27 µSv/h at Kuroko with mean and standard deviation (SD) value of 0.12. For Okehi LGA, the dose rate ranges from 0.06 µSv/h at Ebako to 0.39 µSv/h at Itakpe1 with a mean and SD value of 0.160.070 µSv/h. In Ogori-Magongo LGA, the dose rate ranges from 0.11 µSv/h at Oturu to 0.29 µSv/h at Ogori with a mean and SD of 0.170.048 µSv/h, those at Okene LGA, ranges from 0.10 µSv/h to 0.28 µSv/h with a mean and standard deviation of 0.160.044 µSv/h and finally the dose rate at Ajaokuta LGA, ranges from 0.10 µSv/h to 0.36 µSv/h with a mean and standard deviation of 0.200.076 µSv/h. The average annual effective dose rate is approximately 0.175±0.06 mSv/yr. However, these values are seen to be lower than the yearly recommended value of 1.0 mSv/yr for public exposure and 20.00 mSv/yr for occupational workers.