[01] Uloko Felix Omachoko, Department of Physics, Federal University Lokoja, Lokoja, Nigeria. [02] Agomuo John Chidowerem, Department of Physics, Nigerian Defence Academy, Kaduna, Nigeria. [03] Ige Olumide Oluwasanmi, Department of Physics, Nigerian Defence Academy, Kaduna, Nigeria.

To assess the possible health risk to those working, or living in the vicinity of the Dangote Cement factory Obajana Nigeria, the activity concentration of some Naturally Occurring Radioactive Material (NORMs) namely, ⁴⁰K, ²³⁸U, and ²³²Th at the mining site of Dangote Cement Company Obajana Nigeria, was measured using a sodium iodide (NaI (Tl)) based gamma spectroscopy. Five categories of samples including the raw materials and the finished product (cement) were collected and counted for 18000 seconds. Each of the analysed sample is a mixture of the sample type collected at different locations at the site. The results show that the concentration of ⁴⁰K, ²³⁸U, and ²³²Th in the analysed samples is between 417.25±22.28 and 1783±91.18 Bq/kg, 0.88±0.15 and 63.68±6.86 Bq/kg, and 12.90±0.75 and 29.77±1.73 Bq/kg respectively. The mean concentration of ²³⁸U and ²³²Th are below the recommended mean value, while that of ⁴⁰K is above the world average. The radiological parameters namely, the absorbed dose rate in air, annual effective dose, calculated using the measured activity concentrations were below the recommended values. However, the mean radium equivalent activity was slightly higher than the world average, due to high activity concentration of ⁴⁰K in some of the samples. This does not pose any immediate danger; hence, we conclude that there is no radiological risk to workers at the site.

Cement, Detector, Gamma-ray, Obajana, Specific Activity

[01] Usikalu M. R, Anoka O. C, and Balogun F. A (2011). Radioactivity Measurements of the Jos Tin Mine Tailing in Northern Nigeria. Scholars Research Library ISSN 0976-0970 CODEN (USA): APRRC7. [02] Mahur, A. K et al (2008) "Measurement of natural radioactivity and radon exhalation rate from rock samples of Jaduguda uranium mines and its radiological implications", Nuclear Inst. and Methods in Physics Research, B, 200804. [03] Abbady A. G. E.. (2008) "Radiological significance of Beach sand used for climatotherapy from Safaga, egypt", radiation protection dosimetry, 06/25/2008. [04] Kiplangat, E. (2016). Radioactivity Concentrations and Dose Assessment fo Soil Samples from Wheat Plantation Areas of Narok County, Kenya. School of Pure and Applied Sciences of Kenyatta University. [05] Hall, E. J. (2012). Radiation and Life. Published by the World Nuclear Association. [06] Ifeoluwa, O. P. (2014). Assessment of the natural radioactivity and its radiological hazards in prospective ore deposit sites in Southwestern Nigeria. Conference Proceedings of Nigerian Institute of Physics (pp. 324-332). UYO: Nigeria Institute of Physics. [07] Edward, S. B. (2016). An Assessment of the Impact of Obajana Cement Factory on the Socio-Economic Development of Obajana, Kogi State, Nigeria. An MSc Thesis Submitted to the Department of Geography, Faculty of Physical Sciences, Ahmadu Bello University, Zaria, Nigeria. [08] Afeni, B. T., Cowood, F., Isiaka, F. A. (2008). Assessment of Socio-economic Impacts of Quarrying and Processing of limestone at Obajana, Nigeria: European Journal of social sciences, 6 (4), 16-21. [09] Obajana Cement Project (OCP), (2005). Social and Environmental Impact Assessment: Obajana Cement, Kogi State. [10] Fredrick Oghenebrorie Ugbede. "Distribution of 40K, 238U and 232Th and associated radiological risks in river sand sediments across Enugu East, Nigeria", Environmental Nanotechnology, Monitoring & Management, 2020. [11] International Atomic Energy Agency (IAEA), (2005). International Basic Safety Standard for protection against ionizing radiation and for the safety of radiation sources. Safety series No. 115. IAEA Vienna. [12] United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR), (2000). Sources, Effects, and Risks of Ionizing Radiation. New York: United Nations. [13] Nwankwo, C. U., Ogundare F. O., Folley D. E. (2015). Radioactivity Concentration Variation with Depth and Assessment of Workers' Dose in Selected Mining Sites. Journal of Radiation Research and Applied Sciences. [14] Ajayi, J. O., Balogun, B. B., Olabisi, O. (2012). Natural Radionuclide Content in Raw Materials and the Aggregate Finished Product from Dangote Cement Plc, Obajana, Kogi State. Research Journal of Environmental and Earth Sciences 4 (11): 959-961, 2012, ISSN: 2041-0492. [15] Sylvere Yannick Loemba Mouandza, Alain Brice Moubissi, Patrice Ele Abiama, Thierry Blanchard Ekogo et al. "Radiation background from rock samples and hazards assessment: case of Mounana in Gabon", International Journal of Low Radiation, 2020. [16] International Commission on Radiological Protection (ICRP), (2006). Recommendations of the International Commission on Radiological Protection. Pergamon Oxford: ICRP Publication 103. [17] European Commission, (1999). Report on Radiological Principles Concerning the Natural Radioactivity of Building Materials. Radiation Protection Report 112. [18] Deepa Ranjanie Abeydeera, Rohini Hewamanna, Mahendra Prinath Dias, Palee Mahawatta. "Estimation of Radioactivity and Associated Radiological Hazards of Cement Used in Sri Lanka", OUSL Journal, 2018.