Radiometric And Petrographic Studies Of A Typical Basement Complex Terrain, Southwestern Nigeria

Radiometric and petrographic study was carried out over a typical basement terrain of southwestern Nigeria in order to evaluate possible impact of high radiation in the environment, which can pose any health hazard. In this study, the radiometric mapping was done using a portable hand-held Geiger-Muller counter with the aim of establishing the background radiation level within the campus and possible association with lithology pattern in the area. The petrographic analysis of the rock samples obtained from outcrops of rock masses in the study area revealed that the major minerals are Quartz, Biotite, Plagioclase, Orthoclase, Myrmeckite, Microcline and Opaque minerals. The radiation emitting mineral in these rock samples are Biotite, Orthoclase and Microcline. A strong linear relation was established between the percentage mineral composition in the rocks and the background radiation measured over the study area at 95% confidence level. The local high values in background radiation can be attributed to high percentage of potassium and aluminium minerals in the rock composition as observed over charnockites and migmatite-gneiss. The background radiation level in most of the study area falls within the range of 0.16μSv/hr (1.4mSv/yr) and 0.27μSv/hr (2.36mSv/yr), considered to be within the normal world average background radiation level. In addition to oxyphile and biophile tendency of radioactive elements in the mineral assemblages of the rocks, resulting in their concentration in the organic compounds, humus and other agricultural soils, notable high radiation levels can be attributed to human activities, especially where radiation level is above the 0.27μSv/hr (2.36mSv/yr). High background radiation levels within the range of 0.28μSv/hr (2.45mSv/yr) and 0.38μSv/hr (3.33mSv/yr) recorded in some parts of the study area are at car parks, around laboratories and isolated areas close to the farm in the area.

REFERENCES

[1] UNSCEAR, �Sources and effects of ionizing radiation�, Report to the General Assembly, with Scientific Annexes, New York, USA. 1993.

[2] UNSCEAR, �Sources and effects of lionizing radiations�, Report to the General Assembly, with Scientific Annexes, Vol. 1Sources, United Nations Scientific Committee on the Effects of Radiations, 2000.

[3] IAEA, Uranium Exploration Data and Techniques Applied to the Preparation of Radioelement Maps. IAEA-TECDOC-980, Vienna, 1997.

[4] A. N. Amadi, N. O. Okoye, P. I. Olasehinde, , I. A. Okunlola, Y. B. Alkali, T. A. Ako, and , J.N. Chukwu, �Radiometric Survey as a Useful Tool in Geological Mapping of Western Nigeria�, Journal of Geography and Geology, Vol. 4, No. 1, pp. 242-249, 2012.

[5] IAEA, �Application of Uranium Exploration Data and Techniques in Environmental Studies�, IAEA-TECDOC-827, Vienna, 1995.

[6] I.P. Farai, C.E. Okwunakwe, and O.S. Makinde �Gamma Spectroscopy assay soil samples from waste landfills in Port Harcourt, Nigeria�, Proceedings of 16th International Conference on Radionuclide Meteorology in Cape Town. June-July, Elsevier B.V. 850-854, 2007.
[7] N.N. Jibiri I.P. Farai, and S.K. Alausa, � Activity concentration of Ra-226, Ra- 228 and K-40 in food crops from high background radiation area in Bisichi, Jos, Plateau State, Nigeria�, Radiat. Env. Biophy. Vol. 46, pp. 53 �59, 2007.

[8] G. O. Avwiri, J. M. Egieya, and C. P. Ononugbo, �Radiometric Survey of Aluu Landfill, In Rivers State, Nigeria�, Advances in Physics Theories and Applications. Vol.22, pp. 24-29, 2013.

[9] K. D., Oyeyemi, M. R., Usikalu, A. P., Aizebeokhai, J. A., Achuka, and O., Jonathan, �Measurements of radioactivity levels in part of Ota Southwestern Nigeria :Implications for radiological hazards indices and excess lifetime cancer-risks�, Journal of Physics: IOP Conf. Series: pp. 1-8, 852 (2017) 012042; doi:10.1088/1742-6596/852/1/012042. 2017.

[10] M.E. Noz, and G.Q. Maguire, �Radiation Protection in the Radiologic and Health Sciences�, Henry Kimpton Publishers. London 211p, 1979.

[11] K. Rose, I. Anderson and H. Lonsjo, �Transfer of radiocaesium from soil to vegetation and to grazing lambs in a mountain area in northern Sweden�, J. Environ. Radioact. 26: 237-257, 1995.

[12] N.P. Petropoulos, M.I. Anagnostakis and S.E. Simopoulos, �Attenuation, natural radioactivity content and radon exhalation, rate of building materials�, Environ. Radiact. 61: 257-269, 2002.

[13] L.C. Sujo, M.E.M. Cabrera, L. Villalba, M.R. Villalobos and E.T. Moye, �Uranium-238 and thorium-232 series concentrations in soil, radon-222 indoor and drinking water concentrations and dose assessment in the city of Aldama, Chihuahua, Mexico�, J. Environ. Radioact. 77: 205-219, 2004.

[14] M.J. Frissel, �The Bioavailability of deposited artifical radionuclide: A study of the international union of radioecology working group of soil to plant transfer�, Gro. Chem. Int., 39:91-102, 1994.

[15] I.H. Saleh, A.F. Hafez, N.H. Elanany, H.A. Motaneh and M.A. Naim, �Radiological study of soils food stuff and fertilizers in the Alexandria Region, Egypt�, Turk. J. Eng. Environ. Sci., 31: 9-17, 2007.

[16] A. K Mohanty, D. Sengupta, S. K. Das, V. Vijayan, and S. K. Saha, �Natural radioactivity in the newly discovered high background radiation area on the eastern coast of Orissa, India�, Radiation Measurements, Vol. 38, pp. 153 � 165, 2004.

[17] USEPA, �Radionuclide in the ecosystem. United State Environmental Protection Agency Washington�, 2007.

[18] I.O. Olarinoye, L. Sharifat, A.N. Baba-Kutigi, M.T. Kolo and K. Aladeniyi, �Measurement of background γ radiation level at two tertiary institution in Minna, Nigeria�, Journal of Applied Sciences and Environmental Management, Vol. 14, pp. 59-62, 2010.

[19] K.S.V. Nambi, N.K. Mehta, T.S. Muraleedharan, Y.S. Mayya and S.C. Saha, �Preliminary dose estimates in the high background radiation areas of Orissa coastal region near Chhatrapur�, Proceedings of the Third National Symposium on Environment with Special Emphasis on High Background Radiation Areas, Thiruvananthapuram, Kerala, India, 1994.

[20] P. Chiozzi, V. Pasquale, and M. Verdoya, �Radiometric survey for exploration of hydrothermal alteration in a volcanic area�, Journal of Geochemical Exploration, Vol. 93, pp. 13�20, 2007.

[21] N.E. Bassey, K. Usman, O. Ajibola, �Radiometric Mapping of Song Area and Environs, Hawal Basement Complex, Northeast Nigeria�, International Journal of Science and Technology, Vol.2, No.9, pp. 692-693, 2013.

[22] B.M.R. Green, J.S. Hughes, and X P.R. Hughes, �Radiation Atlas. Natural Sources of Ionizing Radiation in Europe�, CEC, Luxemburg, 1993.

[23] UNSCEAR, �Sources, effects and risk of ionizing radiation�, United Nations, New York, 1988.

[24] B. R. S. Minty, �Fundamental of airborne gamma-ray spectrometry�, AGSO Journal of Australia Geology and Geophysics, Vol. 17, No. 2, pp. 39-50, 1997.

[25] NIMET , �Nigeria Metrological Agency�, Daily Weather Guide, Nigeria Television Authority, Lagos, Nigeria, 2011.

[26] J.A. Adekoya, O. O. Kehinde-Phillips, and A. M. Odukoya, �Geological distribution of mineral resources in southwest Nigeria�, In: A. A. Elueze (Ed.) Prospects for investment in mineral resources of Southwestern Nigeria, pp 1-13, 2003.

[27] G.M. Olayanju, and O. Ojo, �Magnetic Characterization of Rocks Underlying FUTA Campus, Southwestern Nigeria�, Journal of Environment and Earth sciences, Vol. 5, no. 14: 113-127, 2015.

[28] O. A. Ademeso, �Field and Petrographic Relationships between the Charnockitic and Associated Granitic Rock, Akure Area, Southwestern Nigeria�, World Academy of Science, Engineering and Technology, Vol. 71, pp. 626-630, 2010.

[29] N.G. Obaje, �Geology and mineral resources of Nigeria�, Springer Dordrecht Heidelberg, London New York, 221 pp, 2009. http://dx.doi.org/10.1007/978-3-540-92685-6.

[30] M. A. Rahaman, T. R. Ajayi, I. O. Oshin, and F. O. I., Asubiojo, �Trace element geochemistry and geotechnic setting of Ife-Ilesha schist bel�, In: Oluyide, P.O., Mbonu, W.C., Ogezi, A.E., Egbuniwe, I.G., Ajibade, A.C., Umeji, A.C (Eds.). Precambrian Geology of Nigeria. Geological Survey of Nigeria, Publication, pp. 241-256, 1988.

[31] V. O. Olarewaju, �The charnockitic intrusive of Nigeria�. In: Oshin, O. (Ed.). The Basement Complex of Nigeria and its Mineral Resources. Akin Jinad & co, Ibadan, Nigeria, Pp 45-70, 2006.

[32] A. O. Oyinloye, and R. Obasi, �Geology, geochemistry and geotectonic setting of the Pan-African granites and charnockites around Ado-Ekiti, Southwestern Nigeria�. Pakistan Journal of Scientific and Industrial Research, Vol. 49, No.5, pp. 299-308, 2006.

[33] K. A. Shitta, �Lithostratigraphy of Nigeria: An overview�, Proceedings of 32nd Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, Jan. 22-24, 2007.pp. 18-23, 2007.

[34] O. A. Ademeso, �Deformation traits in the charnockitic rocks of Akure area, Southwestern Nigeria�, Asian Journal of Earth Sciences, Vol. 2, No. 4, pp. 113-120, 2009.

[35] ImageJ, �Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, California 95054, U.S.A.�, known as �ImageJ� version 1.40c, 2008.