Soil Radioactivity Levels, Spatial Distribution and Radiation Hazard Assessment in Anambra and Imo States, Southeastern Nigeria
Keywords:
Soil radioactivity, spatial distribution, radiation hazard, gamma spectrometry, Anambra, ImoAbstract
Abstract: This study assessed the radioactivity levels in soil samples from Anambra and Imo States, two regions affected by the Nigerian Civil War. Using a thallium-activated sodium iodide detector, a total of 80 stratified, randomly collected soil samples were analyzed. The detected radionuclides included non-serial ⁴⁰K and decay series of ²³⁸U and ²³²Th, as well as trace levels of the anthropogenic ¹³⁷Cs. Their spatial variability and associated health implications were also evaluated. The average activity concentrations in Anambra State were 835.91 ± 7.40 Bq kg⁻¹ for ⁴⁰K, 21.05 ± 3.65 Bq kg⁻¹ for ²³⁸U, 12.99 ± 0.85 Bq kg⁻¹ for ²³²Th, and 3.88 ± 0.10 Bq kg⁻¹ for ¹³⁷Cs. In Imo State, the respective values were 761.29 ± 6.63, 19.19 ± 2.97, 9.29 ± 1.52, and 5.39 ± 0.25 Bq kg⁻¹. The estimated mean absorbed dose rates were 52.65 nGyh⁻¹ for Anambra and 46.38 nGyh⁻¹ for Imo, corresponding to annual effective dose equivalents of 0.06 mSvy⁻¹ for both states, a value well below the global safety thresholds. Spatial analysis revealed that ⁴⁰K levels were influenced by potassium-rich soils and intensive agricultural practices, while geological formations governed the distribution of ²³⁸U and ²³²Th. This study confirms that current soil usage poses no immediate radiological risks. However, proactive monitoring is recommended to mitigate potential long-term radiological impacts.
References
. United Nations Scientific Committee on the effects of Atomic Radiation (UNSCEAR) 2000. Report of UNSCEAR to the general assembly, United Nations, New York, USA
. Akinloye, M.K., Isola G.A., Ayanlola, P.S., 2018. Determination and Evaluation of Radionuclide Contents in the Soil of Oloru, Kwara State, Nigeria; International Journal of Scientific and Research Publications; 8(8); 628 - 634 http://dx.doi.org/10.29322/IJSRP.8.8.2018.p8081
. Isola, G.A., Oni, O.M., Akinloye, M.K., Ayanlola P.S., 2018. Measurement of Natural Radioactivity in Soil Samples from Ladoke Akintola University of Technology, Ogbomoso South-West, Nigeria; International Journal of Scientific and Research Publications; 8(8); 618 – 627. http://dx.doi.org/10.29322/IJSRP.8.8.2018.p8080
. Isola, G.A., Akinloye, M.K., Amuda, D.B., Ayanlola, P.S., Fajuyigbe A., 2019: Assessment and Evaluation of Enhanced Levels of Naturally Occurring Radionuclides Materials due to Gold Mining in Soil Samples obtained from Iperindo, Osun State, Southwestern, Nigeria; International Journal of Scientific and Engineering Research; 10(9); 1647 - 1657
. United Nations Scientific Committee on the Effects of Atomic Radiation, 2008. Sources and Effects of Ionizing Radiation. Report to the General Assembly with Scientific Annexes. New York, NY, USA
. Manigandan, P.K., and Chandar, S.B., 2014. Evaluation of radionuclides in the terrestrial environment of Western Ghats. J. Rad. Res. Appl. Sci. 7, 310–316. https://doi.org/10. 1016/j.jrras.2014.04.001.
. Ekong, G., Akpa, T., Umaru, I., Lumbi, W., Akpanowo, M., Benson, N., 2019. Assessment of radiological hazard indices from exposures to background ionizing radiation measurements in South-south Nigeria. Int. J. Environ. Monit. Anal. 7 (2), 40–47.
. Luiz do Carmo Leal, A., da Costa Lauria, D., Ribeiro, F.C.A., Viglio, E.P., Franzen, M., de Albuquerque Medeiros Lima, E 2020. Spatial distributions of natural radionuclides in soils of the state of Pernambuco, Brazil: influence of bedrocks, soil types and climates. J. Environ. Radioact. 211 106046 https://doi.org/10.1016/j.jenvrad.2019.106046.
. Sirin, M., 2020. Investigation of accumulation of radionuclides in different tissues of Whiting fish (Merlangius merlangus euxinus Nordmann, 1840) caught on the coasts of Rize in the eastern Black Sea region of Turkey. Microchem. J. 152 104349 https://doi. org/10.1016/j.microc.2019.104349.
. Akinloye, M.K., Isola, G.A., Oladapo, O.O., 2012. Investigation of Natural Gamma Radioactivity Levels and Associated Dose Rates from Surface Soils in Ore Metropolis, Ondo State, Nigeria. Environment and Natural Resources Research 2(1); 140-145. https://doi.org/10.5539/enrr.v2n1p140
. Agbelusi, O.I., Ayanlola, P.S., Akinlabi, I.A., Amusat, T.A., Amuda, D.B., Isola, G.A., 2024. Assessment of Radionuclides Contents in Soil and Food Samples Due to Civil Warin Enugu State, South-Eastern, Nigeria and Its Radiological Hazards. Nigerian Journal of Theoretical and Environmental Physics, 2(2): 76 - 84. https://doi.org/10.62292/njtep.v2i2.2024.17
. Xinwei, L., Lingquig, W., Xiaodan, J., Leipengy., Gelian D., 2006. Specific activity and hazards of archeozoiccambrian rock samples collected from the Weibei area of Xhaanxi, China. Rad. Prot. Dos., 118(3):352–359.Doi: 10.1093/rpd/nci339.
. Gao, J., Cao, C., Luo Z., Zhang X., 2014. Inhalation exposure to particulate matter in rooms with under floor air distribution. Indoor Built Environ., 23:236–245. Doi: 10.1177/1420326X13482478.
. National Population Commission (NPC), 2022. Nigeria Population 2022 (Demographics, Maps, Graphs). worldpopulationreview.com. Retrieved 3 September 2022.
. Adeoje, E.A., Isola, G.A., Ayanlola, P.S., Lawal, M.K., Aremu, A.A., Oni, E.A., Agbelusi, O.I., 2023. Assessment of Radioactivity Concentrations and Radiological indices in some communities around Lafarge Cement Factory, Ogun State, Nigeria. E-Proceeding for International Conference on Advances in Cement and Concrete (ICACCR-2023), 53 – 63. https://cemcon.lautech.edu.ng/e-proceeding-for-ICACCR-2023
. Awokoya, S.O., Ayanlola, P. S., Olatunji, A., Ojeniyi, F.A., Agbelusi, O.I., Orodiran, O.T, Isola, G.A., 2024. Application of Geostatistical Kriging Model in Assessing Exposure to Background Ionizing Radiation and its Radiological Hazard Indices, Malaysian J. Sci. Adv. Tech., vol. 4, no. 4, pp. 464–471. DOI:10.56532/mjsat.v4i4.381
. Ejeh, O.I., 2021. Geochemistry of rocks (Late Cretaceous) in the Anambra Basin, SE Nigeria: insights into provenance, tectonic setting, and other palaeo-conditions. Heliyon VL 7, Issue 10, e08110. Elsevier SN- 2405-8440. https://doi.org/10.1016/j.heliyon.2021.e08110
. Onwuka, S.U., Duluora, J.O., Amaechi, I.E., 2013. Socio-economic impacts of sand and gravel mining activities in Nsugbe, Anambra state, Nigeria. Albanian Journal of Agricultural Sciences, 2013, 12(2), p229
. Eke, B.C., Akomolafe, I.R., Ukewuihe, U.M., and Onyenegecha, C.P., 2024. Assessment of Radiation Hazard Indices Due to Natural Radionuclides in Soil Samples from Imo State University, Owerri, Nigeria. Environmental Health Insights. 2024;18. doi:10.1177/11786302231224581
. Ugbede, F.O., Osahon, O.D., Akpolile, A.F., 2021. Natural radioactivity levels of 238U, 232Th and 40K and radiological risk assessment in paddy soil of Ezillo rice fields in Ebonyi State, Nigeria. Environmental Forensics, 23(1–2), 32–46. https://doi.org/10.1080/15275922.2021.1892881
. Agbalagba, E.O., Chaanda, M.S., and Egarievwe, S.U., 2021. Assessment of solid mineral to soil radioactivity contamination index in selected mining sites and their radiological risk indices to the public. International Journal of Environmental Analytical Chemistry, 103(17), 5539–5557. https://doi.org/10.1080/03067319.2021.1940162
. Joel, E.S., Maxwell, O., Adewoyin, O.O., 2019. Investigation of natural environmental radioactivity concentration in soil of coastaline area of Ado-Odo/Ota Nigeria and its radiological implications. Sci Rep. 2019;9:4219.
. Addo, M.A., Lomotey, J.S., Osei, B., Appiah, K., 2020. Measurement of natural radioactivity in soil dust samples along roadways in high commercial areas of the Ketu South District of the Volta Region, Ghana. Radiat Prot Environ. 2020;43:6-12.
