In this work, a preprocessed aero radiometric survey data of geologic survey map series of Nigeria basement complex sheet 145 was used to map the spatial distribution of ground level concentration of the three radioelements that contribute significantly to the emission of gamma rays, notably potassium (40K), thorium (232Th) and uranium (238U) and estimating the external hazard associated with human exposure due to the elements. The elemental average concentrations of 40K, 232Th and 238U obtained from the survey data are 1.37485%, 24.5297ppm and 5.5491ppm respectively. The relative concentrations of the three elements are in line with the global trend where Th records the highest mean concentration, followed by U with then K recording the least. Except for K, the values of the other elements were found to be above the global crustal abundance ranges of 2 - 2.5% for 40K, 8 – 12 ppm for 232Th and 2 – 3 ppm for 238U. The mean ground level external dose rate was found to be 213.2 ±21.2 nGyh-1. This is about four times higher than the global average terrestrial dose rate of 55 nGyh-1. The computed external hazard index however gives an average value of 0.329, which is within the acceptable limit (<1). External hazard index above this limit were however recorded at three points, spanning a small area of about 0.096 km2. In situ and ground geophysical measurements are therefore
International Atomic Energy Agency, Rdioelement mapping. IAEA Nuclear Energy Series No. NF-T-1.3. IAEA, Vienna, 2010.
D.L Dent, T. L MacMillan R. A Mayr, W. K Chapman, and S. M Berch, Use of Airborne Gamma Radiometrics to Infer Soil Properties for a Forested Areain British Columbia, Canada. Journal of Ecosystems and Management (JEM). 14(1), pp. 1-10, 2013.
I.O Oshin, and M. A Rahaman, Uranium favourability study in Nigeria. Journal of African earth sxiences, 5(2), pp. 167-175, 1986.
Montaj 256-channel radiometric Processing. Radiometric Processing Extension for Oasis montaj v7.5 user guide and tutorial. Geosoft, 2010.
International Atomic Energy Agency, Guidelines for radioelement mapping using gamma ray spectrometry data. IAEA-TECDOC-1363, IAEA Vienna, 2003.
International Atomic Energy Agency,. The use of gamma ray data to define the natural radiation Environment. IAEA-TECDOC-566, IAEA, Vienna, 1990.
B. R. S Minty, Fundamentals of airborne gamma-ray spectroscopy. AGSO Journal of Australian Geology and Geophysics. 17(2), pp. 39-50, 1997.
A. G Amuda, T. A. Adedokun, O. A. U Uche and A. K Amuda, Engineering geological characterization of basement rocks for construction aggregates: a case study of Kajuru area, Kaduna Nigeria. Civil Engineering Research, 6 (12), pp. 144-153, 2014.
A. N Udo, Note on the geology of sheet 145 (kajuru), Nigeria Geological Survey Agency, Kaduna, 1973.
F. A Tikhomirov, and A. I Shcheglov, Main investigation results on the forest radioecology in the Kyshtym and Chernobyl accident zones. Science of the Total Environment, 157, 45-57, 1994.
N. G Obaje,. Geology and Mineral Resources of Nigeria Lecture Notes in Earth Sciences. Springer, Springer-Verlag Berlin Heidelberg, 2009.
I. O Olaniyan, J. C Agunwamba, and J. O Ademiluyi, Lithologic characteristics of parts of the crystalline basement complex of northern nigeria in relation to groundwater exploitation. ARPN Journal of Engineering and Applied Sciences, 5 (7), pp. 56-60, 2010.
S. W Reford, and D, James, Nigeria’s Nationwide High-resolution Airborne Geophysical Surveys. SEG Denver 2010 Annual Meeting. 1835-1839.
Fugro Instruments, Australia, Exploranium radiation detection system, 2017.
B. Senthilkumar, V. Dhavamani, S. Ramkumar, and P. Philominathan, Measurement of gamma radiation levels in soil samples from Thanjavur using γ-ray spectrometry and estimation of population exposure. J Med Phys. 35(1), pp. 48–53, 2010.
I. Hossain, N. Sharip, and K. Viswanathan, Efficiency and resolution of HPGe and NaI(Tl) detectors using gamma-ray spectroscopy. Scientific Research and Essays, 7(1), pp. 86-89, 2012.
International Atomic Energy Agency, Airborne Gamma-Ray Spectrometer Surveying. Vienna, Austria. Technical Report Series No. 323, IAEA, Vienna, 1991.
N. E Norbani, N. A Abdullah-Salim, and A. T Abdul Rahman, Measurement of terrestrial gamma radiation dose-rate (TGRD) level in soil samples from the district of Rembau, Malaysia, using high-purity Germanium detectors. IOP Journal of Physics Conference Series 546, 2016.
United Nations Scientific Committee on The Effects of Atomic Radiation, Exposures from Natural Sources of Radiation, Report, UNSCEAR, 1988.
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