Assessment of Radionuclide Concentrations in Water Supply from Bore-holes in Ogbomosoland, Western Nigeria

The level of radionuclide concentration in water from bore-holes in selected areas of Ogbomosoland, a region consisting of five local governments, was determined. Concentration of 238 U, 232 Th, and 40 K was determined for the water samples from eight bore-holes around Ogbomosoland by γ-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyzer. All the water samples from these bore-holes were found to contain acceptable levels of radionuclides with mean activity values of 3.98 ±0.26, 11.00 ±2.58, and 17.73 ± 5.04 Bql -1 for 40 K, 232 Th, and 238 U, respectively showing that the mean activity of 238 U for all the samples is the highest when compared with those of 40 K and 232 Th. Water samples from Ikoyi had the highest radionuclide content although 40 K concentration was below detectable level. Water samples from Gambari were next to Ikoyi in radionuclide content, followed by Saja, Ajinopai, Kajola, Isale-Ora, Iresa-Apa, and Owode in that order. The mean absorbed dose rate for all the area is 0.123 mSvyr -1 which is very low when compared to the recommended limit of 1mSvyr -1 for bore-hole water. Overall, the radionuclide concentration of the bore-hole water supply in Ogbomosoland is, negligible and poses no radiological hazards to the public.