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Radioactivity distribution and transfer factor (TF) in plants are crucial parameters used to assess radioactive contamination in the environment, impact of soil radioactivity on agricultural crops and its risks to humans. The root crop cassava (Manihot esculenta) provides about 50 percent of the calories consumed in Nigeria. Gamma - ray spectroscopy was used to measure activity concentrations of 226Ra, 232Th and 40K in cassava root and soil. The average activity concentration of 40K, 226Ra and 232Th in cassava was 565.31± 13.17, 21.89±5.94 and 817.28±2.52 Bqkg-1 respectively. The mean activity concentration 40K, 226Ra and 232Th in soil range from 92.07±35.08 to 689.28±14.35 Bqkg-1with a mean value of 413.64±21.22 Bqkg-1, 5.37 ± 8.90 to 64.93 ± 7.23 Bqkg-1 with a mean value of 54.43 ± 3.22 and BDL to 928.15 ± 2.36 Bqkg-1 with a mean value of 561.67 ± 2.21 Bqkg-1. The transfer values for 226Ra, 232Th and 40K were in the range of 0 to 1.81, 0 to 3.41 and 0.68 to 4.5 respectively. The high value of transfer factor for 40k may be due to its importance in plant growth, fertilization and adaptability of plant to environmental pressures. It may have also been enhanced by the application of NPK fertilizers in those farms. Thorium showed the highest mean transfer factor which may be due to its higher accumulation in soil and higher uptake by plants (Figure 3). The average transfer factors of 226Ra (0.99) < 40K (1.55) < 232Th (1.66) show that although activity concentration of the natural radioisotopes in the area under study are high, the rate at which they are transferred to cassava are still moderate. The average values of radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose rate (AEDE), internal hazard index and excess life cancer risk (ELCR) are 1009.27 Bqk-1, 346.50 nGyh-1, 1.51 mSvy-1, 2.78 and 3.92 x 10-3 for respectively. These values were higher than their corresponding permissible values of 370Bqk-1, 55nGyh-1, 1.0 mSvy-1, 1.0 and 0.29 x 10-3 respectively. The mean values of Hex and Hin are greater than unity and may, therefore, constitute a significant radiological health risk. The mean annual gonad dose estimated value of 2943.90 mSvy-1 was above the world acceptable value of 300 mSvy-1 and the annual effective dose in all the samples except in few locations as shown in Figure 2, exceeded the safe value of 1.0 mSvy-1. The use of soil from these farms and the crops may constitute a threat to the bone marrow and general health conditions of the inhabitants.
Uosif MAM, Mostafa AMA, Elsaman R, Moustafa E. Natural radioac tivity levels and radiological hazards indices of chemical fertilizers commonly used in upper Egypt. Journal of Radiation Resources, Applied Science. 2014;7:430-437.
Ei-Taher A, Abbady Adel GE. Natural radioactivity levels and associated radiation hazards in Nile river sediments from Aswan to El-minia, upper Egypt. Indian Journal. 2012;50:224-230.
Vandenhove H, Olyslaeger G, Sanzharova N, Shubina O, Reed E, Shang Zand Velasco H. Proposal for new best estimates of the soil to plant transfer factor of U, TH, Ra, Pb and Po. J. Environ. Radioact. 2009;100:721-732.
Harb S. Natural radioactivity concentration and annual effective dose in selected vegetables and fruits. Journal of Nuclear and particle Physics. 2015;5(3):70-73.
World Health Organisation (WHO). Guidelines for drinking-water quality – 4, Fourth Edition; 2011.
Ononugbo CP, Avwiri GO, Tutumeni G. Measurement of natural radioactivity and evaluation of radiation hazards in soil of Abua/Odual district of Rivers state, Nigeria, using multivariate statistical approach. British Journal of Science. 2016;4(1):3.
Asaduzzaman K, Khanadakar MU, Anin YM, Bradley DA, Mahat RH, Nor RM. Soil-to- root vegetable transfer factors for 226Ra, 232Th, 40K and 68Y in Malaysia. J. Environ. Radioact. 2014;135:120-127.
Long WJ, Leland W. Tarne, Malcolm P. North. Aligning smoke management with Ecological and public health goals. J. Fores. 2017;116(1):76-86.
FAO. The state of food and Agriculture 2008. Biofuels; prospect, risks and opportunities. Viale delle terme di Caracalla, 00153 Rome, Italy; 2008.
Amposah J. Insight: Cassava farming in Ghanah; the business in it; 2016.
Available:https://www.topbusinessjournal.com/insight-cassava farming-ghana-business. Accessed 23/09/2017.
Adjei-Nsia S, Sakyi-Dawson O. Promoting cassava as an industrial crop in Ghana: Effects on soil fertility and farming system sustainability. Appl. Environ. Soil Sci. 2012;1:1-8.
Svetlana G, Gordana V, Branislava M, Petrujkić B. Natural and anthropogenic radioactivity of foodstuffs, mosses and soil in the Belgrade environment. Arch. Biol. Sci. 2010;62(2):301-307.
Faanu A, Adukpo O, Okoto D, Diabor E, Darko EA, Emi-Reynolds A. Determination of radionuclides in underground water sources within the environments of university of cape coast. Research Journal of Environmental and Earth Sciences. 2011;3(3):269-274.
IAEA-TECDOC 1472. Proceedings of an international conference on naturally occurring radioactive materials (NORM IV). Szczyrk, Poland; 2004.
UNSCEAR. Sources, effects and risks of ionizing radiation. United Nations Scientific Committee on the Effects of Atomic Radiation, Report to the General Assembly, with Annexes, New York; 2000.
IAEA. International safety standards for protection against ionizing radiation and the safety of radiation sources. Safety series No. 1996;115:10-16.
Tawalbeh AA, Samat SB, Yasir MS, Omar M. Radiological impact of drinks intakes of naturally occurring radionuclides on adults of central zone of Malaysia. Malaysian Journal of Analytical Sciences. 2012; 16(2):187–193.
IAEA. Guidelines for radioelement mapping using gamma ray spectrometry data. IAEA-TECDOC-1363; 2003.
IAEA. (International Atomic Energy Agency). A guidebook for the measure-ments of radionuclides in food and the environment, Technical Report Series 295, Vienna; 1989.
Saleh IH, Hafe AF, Alanary NH, Motaoveh HA, Naim MA. Radiological study of soils, foodstuff and fertilizers in the Alexandria region, Egypt, Turkey Journal of Environ-mental Science. 2007;31:9-17.
Shanthi G, Kumaran JTT, Raj GAG, Maniyan C. Transfer factor of the radio-nuclides in food crops from high-background radiation area of south west India. Radiation Protection Dosimetry. 2012;149(3):327-332.
Sabbarese C, Stellato L, Cotrufo MF, D’Onofrio A, Ermice A, Lubritto C, Terrasi F, Alfieri S, Migliore G. Dependence of radionuclide transfer factor on plant growth stage. Environmental Modeling and Software. 2002b;17(6):545-551.
IAEA (International Atomic Energy Agency). The interception, initial and post deposition retention by vegetation of dry- and wet-deposited radionuclides, Vienna; 1995.
United Nations Scientiﬁc Committee on the Effect of Atomic Radiation (UNSCEAR). Report to the general assembly. Annex B: exposures of the public and workers from various sources of radiation; 2008.
Eriksson J, Öborn I, Jansson G, Andersson A. Factors influencing Cd-content in crops. Results from Swedish field investigations. Swedish Journal of Agricultural Resources. 1996;26:125–33.
Alsaffar MS, Jaafar MS, Kabir NA, Ahmad N. Distribution of 226Ra, 232Th, and 40K in rice plant components and physic-chemical effects of soil on their trans-portation to grains. Journal of Radiation Resources Applied. Science. 2015;8(3): 300-310.
Al-masri MS, Al-Akel B, Nashawani A, Amin Y, Khalifa KH, Al-Ain F. Transfer of 40K, 238U,210Pb and210 Po from soil to plant in various locations in South of Syria. Journal of Environmental radioactivity. 2008;99(2):322-331.
Tchokossa P, Olomo JB, Balogun FA, Adesanmi CA. Assessment of radioactivity contents of food in the oil and gas producing area in Delta State, Nigeria International Journal of Science and Technology. 2013;3:245–50.
Ononugbo CP, Avwiri GO, Tutumeni G. Measurement of natural radioactivity and evaluation of radiation hazards in soil of Abua/Odual district of Rivers state, Nigeria, using multivariate statistical approach. British Journal of Science. 2016;4(1):3-48.
Avwiri GO, Agbalagba EA. Assessment of natural radioactivity associated radiological health hazard indices and soil to crop transfer factors in cultivated area around a fertilizer factory in Onne, Nigerian Journal of Environmental Radioactivity; 2013.
Dragovic S, Jankovic-Mandict L, Dragovic M, Dokie M, Kavacevic J. Lithogenic radionuclides in surface soils of Serbia: Spatial distribution and relation to geological formations. Journal of Geo-Chemical Exploration. 2014;142:4-10.
Jibiri NN, Abiodun TH. Effects of food diet preparation techniques on radionuclide intake and its implications for individual ingestion effective dose in Abeokuta, southwestern Nigeria. World Journal of Nuclear Science and Technology. 2012;2: 106-113.
United Nations Scientiﬁc Committee on the Effects of Atomic Radiation (UNSCEAR). Sources and effects of ionizing radiation (Report to the General Assembly).United Nation, New-York; 2000.
Nkuba LL, Sungita YY. Radioactivity levels in maize from high background radiation areas and dose estimates for the public in Tanzania. Physical Science International Journal. 2017;13(3):1-8.
Idowu M. Physics in Radiation Application and Safety for National Technological Advancement. Nigeria Institute of Physics Conference; 2014. Pulhani V, Dafauti S, Hegde A, Sharma R, Mishra U. Uptake and distribution of natural radioactivity in wheat plants from soil. Journal of Environmental Radioactivity. 2005;79(3): 331-346.
Ibiotola A. Gilbert, Ajanaku Olanrewaju, ilori, Abiola Olawale, Aremu RO, Omosebi AAI. Measurement of 40K, 232Th and 238U and the associated Dose rates in soil and commonly consumed foods (vegetables and tubers) at Okitipupa, Ondo State, Southwestern Nigeria. Asian Journal of Research and Reviews in Physics. 2018; 1(1):1-18.
Martinez-Aguirre A, Garcia-Leon M. Radioactivity impact of phosphate ore processing in a wet marshland in south-western Spain. Journal of Environmental Radioactivity. 1997;34:45–57.
Saeed MA, Yusof SS, Hossain I, Ahmed R, Abdullah HY, Shahid M, Ramli AT. Soil to rice transfer factor of the natural radionuclides in Malaysia. Roman Journal of Physics. 2012;57(9–10):1417–1424.
Karunakara N, Rao C, Ujwal P, Yashodhara I, Kumara S, Ravi P. Soil to rice transfer factors for 226Ra, 228Ra, 210Pb, 40K and 137Cs: A study on rice grown in India. Journal of Environmental Radio-activity. 2013;118:80-92.
Osiga AD. radiation level measurement in Delta State University, campus 1, Abraka, Nigeria. Science-African Journal of Scientific Issues, Research and Essays. 2014;2(11):479-490.