Analysis of Natural Radioactivity and Radiation Exposure Levels in Eburru Geothermal Field, Kenya

Authors(3) :-Solomon Wangila Namaswa, Collins Okoth, Brian Makori

In Kenya, the use of geothermal energy for power supply has becomes increasingly attractive as part of an alternative energy mix and from the current rate of geothermal installation it may soon overtake hydro as the leading source of energy. Although geothermal energy has been termed as clean, risks associated with the use of deep thermal fluids require intensive evaluation and communication made to the community and with the public since natural radioactivity is crucial for the earth system as the slow decay of radioactive elements produces approximately half of the heat that drives major earth’s processes such as continental drift, ocean spreading and plate tectonics. The results of a survey on the radionuclide concentration undertaken in Eburru geothermal field in different rock formations are hereby presented. This research measured activity concentrations of the naturally occurring radioactive elements 40K, 238U, and 232Th by use of NaI(Tl) gamma-ray spectrometer, estimated the absorbed dose rate, annual effective dose rates and the hazards index due to natural radionuclides and their decay products in Eburru geothermal field. The mean activity concentrations concentration of 238U, 232Th and 40K were 70.521±10.48Bqkg-1, 50.65±5.13Bqkg-1 and 588.511±156.14Bqkg-1 in rock samples. The average absorbed dose rates, annual effective dose rate and hazard index in rocks samples were found to be 87.71± 6.44 nGyh-, 0.11±0.01mSvy-1 and 0.50±0.03. From the obtained results, the studied hazard indices were within the world acceptable safety limits and therefore human exposure to radiation is within safety levels. This indicates that the level of the studied radioactive elements in geothermal rocks within Eburru geothermal field is within the acceptable range.

Authors and Affiliations

Solomon Wangila Namaswa
Department of Physics, Multimedia University of Kenya
Collins Okoth
Department of Electrical and Electronic Engineering, Multimedia University of Kenya
Brian Makori
Department of Physics, Multimedia University of Kenya

Geothermal Field, Radioactivity, Dose Rate, External Hazard Index

  1. Kelley, S. (2010). Geothermal Energy, Lite Geology. New Mexico Bureau of Geology & Mineral Resources, a Division of New Mexico Tech
  2. Fowler, C.M.R. (1990). The Solid Earth: An Introduction to Global Geophysics. Cambridge University Press.
  3. Riaroh, D and Okoth, W (1994). The Geothermal Fields of the Kenya Rift, Techtonophysics 236: 117-130
  4. Achola, S.O., Patel, J.P., Mustapha, A.O. and Angeyo, H.K. (2012). Natural Radioactivity in the High Background Radiation Area of Lambwe East, Southwestern Kenya, Radiation Protection Dosimetry, 2 pp 1-6.
  5. Patel, J.P. (1991). Environmental Radiation Survey of the Area of High Background Radioactivity of Mrima Hill of Kenya, Discovery and Innovation 3(3): 31-36.
  6. Mustapha, A.O. (1999). Assessment of Human Exposures to Natural Sources of Radiation in Kenya, Radiation Protection Dosimetry, 82:285-292.
  7. Tambo, P. S. (2014). Multivariate Characterization of Natural Radioactivity Systematics in Lake Magadi Basin Geothermal System In Relation To Quality of Trona Deposits. Msc. Thesis, University of Nairobi
  8. UNESCO, (2008). Great Rift Valley Eco-system, United Nations Educational, Scientific and Cultural Organization World Heritage Centre Report
  9. Ouma, P.A. (2009). Geothermal Exploration and Development of the Eburru Geothermal Field. Presented at Short Course IV on Exploration for Geothermal Resources, organized by UNU-GTP, KenGen and GDC, at Lake Naivasha, Kenya.
  10. Wetang’ula, G.N., Kubo, B.M., Were J.O., and Omenda, P.A. (2003). Environmental Impact Assessment study report, Eburru geothermal power project, Naivasha District (2003)
  11. Kandie, R.J. (2014). Eastern Rift Structural Geology – Tectonics, Volcanology and Geothermal Presented at Short Course IX on Exploration for Geothermal Resources, organized by UNU-GTP, GDC and KenGen, at Lake Bogoria and Lake Naivasha, Kenya,.
  12. Omenda, P.A. (2008). Status of Geothermal Exploration in Kenya and Future Plans for Its Development. Presented at Short Course III on Exploration for Geothermal Resources, organized by UNU GTP and KenGen, at Lake Naivasha, Kenya.
  13. Ramasamy V, Senthil S., Meenakshisundaram V. and Gajendran V. (2009). Measurement of Natural Radioactivity in Beach Sediments from North East Coast of Tamilnadu, India, Resource Journal on Appropriate Technology and Scientific Engineering, 1 (2): 54-58.
  14. UNSCEAR, (2000). Sources and Effects of Ionizing Radiation; United Nation Scientific Committee on the Effects of Atomic Radiation Annex A.B. New York.
  15. Hafezi, S., Amidi J. and Attarilar A. (2005). Concentration of Natural Radionuclides in Soil and Essential Exposure to the Public in Tehran, Iran. J. Radiat. Res, 3(2), pp 85-88.
  16. Tchokosse, P., Olomo, J.B. and Osibota, O.A., (1999). Radioactivity in the Community Water Supplies of Ife-Central and Ife-East L.G.A.’S Osun State, Nigeria. Nucl. Instr. and Methods in Phys. Res. (A422:780-784).
  17. Ashraf, E.M, Higgy R H and Pimpl, M (2001): Radiological Impact of Natural Radioactivity in Abu-Tarter phosphate deposits, Egypt Journal of Environmental Radioactivity,Vol. 55, pp 255-267.
  18. Otwoma, D., Patel, J.P., Bartilol, S.K. and Mustapha, A.O. (2013). Estimation of Annual Effective Dose and Radiation Hazards Due to Natural Radionuclides in Mount Homa
  19. Abdi, M. R., Faghihian, H., Mostajaboddavati, M., Hassanzadeh, A. & Kamali, M. (2006). Distridution of Natural Radionuclides and hot points in coasts of Hormozgan, Persian Gulf, Iran. Journal of Radioanalytical and Nuclear Chemistry, 270(2), 319-324
  20. El Arabi, A.M. (2005). Natural radioactivity in sand used in thermal radiotherapy at the Red Sea coast. J. Environ. Radioact. 101, 165–169.
  21. Lu X, Zhang X. Measurement of natural radioactivity in beach sands from Rizhao bathing beach, China. Radiat Prot Dosimetry 2008;130:385-8.
  22. Kipngeno, R.C. (2015). Gamma Ray Spectroscopic Analysis of Soil and Green Tea Leaves of Kericho County. Msc. Thesis, Kenyatta University
  23. Lagat, J.K. (2004). Geology, Hydrothermal Alteration And Fluid Inclusion Studies Of Eburru Domes Geothermal Field, Kenya. Msc. Thesis, University of Iceland
  24. Selvasekarapandian, S., Manikandan, N., Sivakumar, R., Balasubramanian, S., Venkatesan, T.,  Meenakshisundram, V.,  Ragunath, V.M. and  Gajendran, V. (1999) Gamma Radiation Dose From Radionuclides In Soil Samples Of Udhagamandalam (Ooty) In India. Radiation Protection Dosimetry, 82(3) 225-228.
  25. Mohanty, A. K., Sengupta, D., Das, S. K., Vijayan, V. and Sahab, S. K. (2004). Natural Radioactivity in the New Discovered High Background Radiation Area on the Eastern Coast of Orissa, India, Radiation Measurements 38, 153-165.
  26. Atambo, V., O. (2011). Determination of Naturally Occurring Radioactive Elements and Radiation Exposure Levels in the Soapstone Quarries of Tabaka Region of Kisii District, Kenya, Msc, Thesis, Jomo Kenyatta University of Agriculture and Technology .
  27. Malanka A, Pessina V, Dallara G (1993). Assessment of the natural radioactivity in the Brazilian state of Rio Grande. Health Phys., 65(3): 298-302.
  28. EL-Taher, A. (2010). Gamma Spectroscopic Analysis and Associated Radiation Hazards of Building Materials Used on Egypt, Radiation Protection Dosimetry, 138(2), pp167-173

Publication Details

Published in : Volume 4 | Issue 1 | January-February 2018
Date of Publication : 2018-02-28
License:  This work is licensed under a Creative Commons Attribution 4.0 International License.
Page(s) : 841-846
Manuscript Number : IJSRSET1841131
Publisher : Technoscience Academy

Print ISSN : 2395-1990, Online ISSN : 2394-4099

Cite This Article :

Solomon Wangila Namaswa, Collins Okoth, Brian Makori, " Analysis of Natural Radioactivity and Radiation Exposure Levels in Eburru Geothermal Field, Kenya, International Journal of Scientific Research in Science, Engineering and Technology(IJSRSET), Print ISSN : 2395-1990, Online ISSN : 2394-4099, Volume 4, Issue 1, pp.841-846, January-February-2018.
Journal URL : http://ijsrset.com/IJSRSET1841131

Follow Us

Contact Us