Radiometric Evaluation Naturally Occurring Radionuclides in Some Ongoing Drilled Boreholes across Keffi Town of Nasarawa State, Nigeria

This study evaluate the existence radionuclides in some Ongoing dug boreholes across Keffi town of Nasarawa State, Nigeria using a hand held interceptor TM – Thermo scientific radio nuclear identiFINDER designed for in situ operation. Gamma Activity, possible radionuclide present and their trust levels, Exposure Dose Rate, Absorbed Dose Rate, Effective Dose Rates and Excess Lifetime Cancer Risk were determined. Results obtained shows that the Gamma Activity Level ranged from 0.243 to 0.589 mrem/hr with the mean of 0.441 mrem/hr. Exposure Dose Rate of the study area ranged from 2.43 to 5.89 µSv/hr with the mean of 4.41 µSv/hr. The local miners in the study area are subjected to Absorb Dose Rate ranging from 2430 to 5890 nGy/hr with the mean value of 4410 nGy/hr. Effective Dose Rate of the area under investigation were ranged from 0.42 to 0.99 mSv/yr with a mean of 0.74 mSv/yr. The Excess Lifetime Cancer Risk of the area ranged from 1.47 x 10-3 to 3.47 x 10-3 with the mean of 2.60 x 10-3. The result also shows that there is Palladium (103Pd), Iodine (125I), Samarium (153Sm), Chromium (51Cr) and Tallium (201Tl) in significant percentage. It is concluded that natural radionuclides pollution in the drilling sites are an issue of health concern, since the radiation exposure level for workers in the study area is found to be high according to regulatory rules.