Radiation Risk Assessment of Soil in Idomi, Cross River State, Nigeria


  • N. O. Chiaghanam Department of Radiography and Radiological Science, University of Calabar, Calabar
  • C. C. Nzotta
  • L. B. Enweani




Radiation, Risk, Assessment, Soil, Activity


In this thesis work, the radiation risk from soil samples in Idomi community located at Yakurr Local Government Area of Cross River State, Nigeria was studied. This was because of an earlier study that revealed the presence of high radioactivity in the area. This study aim to determine the background radiation levels, estimate their effective dose, the mean activity concentrations of the radionuclide and the radiological implications of the radioactivity levels in Idomi. Thirty (30) soil samples were collected and analyzed. The baseline average annual outdoor effective dose, mean activity concentration, gamma absorbed dose and radiological hazard index were studied. Results from this study indicate that three (3) radionuclide namely 40K, 238U and 232Th were present in the soil samples analyzed.  The mean activity concentrations of 40K, 238U and 232Th in the soil samples were 506.13±9.30, 41.14±3.59 and 84.52±20.88 Bqkg-1 respectively.  The calculated mean external and internal hazard index was 0.62 and 0.71 respectively. The calculated mean gamma index was 0.86. The Raeq in the soil samples was 227.34 Bqkg-1. The calculated absorbed gamma dose from the sample was 110.31nGy-1 and a mean annual outdoor effective dose of 1.35mSvy-1.  Compared with global average values of 10-200nGyh-1, 2.4 mSvy-1and Raeq of 370BqKg-1 they can be said to be within the normal range. From this study, the chances of occurrence of health effects from exposure to natural terrestrial gamma radiation in Idomi can be said to be low.  This may be possible if the baseline levels obtained from this study can be kept constant by keeping the environment free of radioactive pollution.


• Akhtar, N. and Tufail, M. (2007). Natural radioactivity intake in wheat grown on fertilized farms in two districts of Pakistan. Radiat. Prot. Dosim. 123: 103-12.

• Beretka, J. and Mathew, P.T. (1985). Natural radioactivity of Australian building materials, industrial wastes and by-products. Health Physics 48: 87-95.

• Cottons, E. (1990). Actions against radon at the international level. Proc. Symp. ON SRBII (Journey Radon)(Brussels: Royal Society of Engineers and Industrial of Belgium) 95.

• Deworm, J.T., Slegers, W.; Gillard, J.; Flemal, J.M. and Culst, J.P. (1998). Survey of the natural radiation of Belgium territory as determined by different methods. Radiat Prot. Dosim 24: 347-351.

• Ekwueme, B. N. (1990). On the occurrence of crystalline (basement complex) rock in Ugep, Nigeria. J. Min. Geol., 26 1:69-74.

• Ekwueme, B.N. (1995). Geochemistry of crystalline basement rocks in SW Ugep, Nigeria. Dec-Ford Journal of Pure and Applied Sciences 11:15-28.

• El-Arabi, A.M. (2005). Natural radioactivity in sand used in thermal therapy at the Red Sea Coast. J. Environs Radioact 81: 11-19.

• European Commission (1999). Radiological protection principles concerning the natural radioactivity of building materials. Radiation Protection 112 (Brussels: European Commission) 100-101.

• Hendry J. H. Simmon S. L. Wojcik A., Sohrabim M, Burkart W, Cardis E, Laurier D, Timarche M. and Hayata I. (2009). Human exposure to high natural background radiation: what can it teach us about radiation risk? J. Radiol.Proct.29:A29-A42

• Krieger, R. (1981). Radioactivity of construction materials. Bentonwerk Fertigtiel Tech. 47: 468.

• Krisiuk, E. M., Tarasov, S. T. and Shamov, V.P. (1971). A study on radioactivity of building materials (Leningrad: Research Institute of Hygiene) 106.

• NRPB (1994). Radiation Dose-Maps and Magnitudes. At a Glance series.

• Quindos, L.S.; Fernandez, P.L.; Soto, J. ; Rodenas, C. and Gomez, J. (1994). Natural radiactivity in Spanish Soils. Health phys (66): 194-200.

• Righi,S. and Bruzzi, L. (2006). Natural radioactivity and radon exhalation in building materials used in Italian dwellings. J. Environ. Radioact, 88: 158-70.

• Singh, S.; Raci, A. and Mahajan, R. K. (2005). 226-Ra, 232-Th and 40-K analysis in soil samples from some areas of Punjab and Himachal Pradesh, India using gamma ray spectrometry. Radiat. Meas. 39:431-439.

• Tsai T, Chun-chih L, Tzu-Wen W and Tieh-chii C. (2008). Radioactivity concentrations and dose assessment for soil samples around nuclear power plant IV in Taiwan J. Radio Prot. 28: 347-360.

• UNSCEAR (2000). Sources, Effects and risks of ionization radiation. Report to the general assembly, with scientific Annexes B. Exposures from Natural Radiation sources (New York: UNSCEAR) 67.

• Uwah E. J. 1993). The use of Aeroradiometric data for environmental monitoring: A case study of Ugep area of Cross River State, Nigeria. Nigeria J. Phys. Vol. 5, p. 48-57.

• Varley, N. R. and Flowers, A.G. (1998). Indoor radon prediction from soil gas measurement. Health phys. 74:714-8.




How to Cite

Chiaghanam, N. O., Nzotta, C. C., & Enweani, L. B. (2019). Radiation Risk Assessment of Soil in Idomi, Cross River State, Nigeria. Asian Journal of Applied Sciences, 7(1). https://doi.org/10.24203/ajas.v7i1.5593