Spatial distribution mapping and radiological hazard assessment of groundwater and soil gas radon in Ekiti State, Southwest Nigeria

  • Y. Ajiboye
  • M. O. IsinkayeEmail author
  • M. U. Khanderkar
Original Article


Groundwater constitutes the major source of utility water in Ekiti State with the majority of the population depending on groundwater for drinking and other household uses. Soil in the area is commonly used as a component of building materials, which may produce radon in the indoor environment. Excessive concentrations of radon in water and soil can cause radiological health risks to human as witnessed by the increased cases of lung cancer among non-smokers in Nigeria, which may be traceable to the ingestion and inhalation 222Rn in drinking water and indoor air. In the present study, comparative in situ measurements of radon in groundwater and soil gas were carried out at one hundred selected locations across the Ekiti State in southwest Nigeria, using a RAD7 radon detector to generate a radon distribution map and to estimate radiation hazards due to radon. The concentrations of radon in groundwater ranged from 0.9 to 472 Bq L−1 with a mean of 34.7 ± 4.4 Bq L−1, while those of soil gas ranged from 0.1 to 315 kBq L−1 with a mean of 38.9 ± 1.4 kBq L−1. The total annual effective dose due to inhalation and ingestion of radon in groundwater amounted to 94.7 µSv year−1, which is lower than the reference dose of 100 µSv year−1 recommended by the World Health Organization (WHO). The radon map generated for groundwater and soil gas identified three distinct areas with radon levels ranging from low to high. The results of this study show that some locations (Emure, Gbonyin, Ijero and Ikole) show mean total annual effective doses which are higher than the recommended limit. It can then be inferred that the groundwater samples pose significant radiological hazards to the population and that the noticed increase in lung cancer cases may be attributed to the consumption of groundwater in the area.


222Rn Groundwater Soil gas Radiation exposure Radon map 



Authors are grateful to the Founder of Afe Babalola University, Ado Ekiti (ABUAD), Aare Afe Babalola (CON, SAN, LL.D) and the Management of the University for the provision of the equipment used in this study.


  1. Abdallah SM, Habib RR, Nuwayhid RY, Chatila M, Katul G (2007) Radon measurements in well and spring water in Lebanon. Radiat Meas 42(2):298–303CrossRefGoogle Scholar
  2. Adepelumi AA, Ajayi TR, Ako BD, Ojo OA (2005) Radon soil gas as a geological mapping tool: a case study from basement complex of Nigeria. Environ Geol 48(6):762–770CrossRefGoogle Scholar
  3. Ajayi OS (2000) Distribution of Natural radioactivity in rocks from Ikogosi-Ekiti, Southwestern Nigeria and its radiological implications. Health Phys 79(2):192–195CrossRefGoogle Scholar
  4. Ajayi IR, Kuforiji OO (2001) Natural radioactivity measurements in rock samples of Ondo and Ekiti states in Nigeria. Radiat Meas 33(1):13–16CrossRefGoogle Scholar
  5. Akinbode OM, Eludoyin AO, Fashae OA (2008) Temperature and relative humidity distributions in a medium-size administrative town in southwest Nigeria. J Environ Manag 87(1):95–105CrossRefGoogle Scholar
  6. Akinsanola AA, Ogunjobi KO (2014) Analysis of rainfall and temperature variability over Nigeria. Global J Human-Soc Sci (B) 14(3):11–40Google Scholar
  7. Al-Bataina BA, Ismail AM, Kullab MK, Abumurad KM, Mustafa H (1997) Radon measurements in different types of natural waters in Jordan. Radiat Meas 28:591–594CrossRefGoogle Scholar
  8. Al-Kazwini AT, Hasan MA (2003) Radon concentration in Jordanian drinking water and hot springs. J Radiol Prot 23:439–448CrossRefGoogle Scholar
  9. Amrani D, Cherouati DE, Cherchali MEH (2000) Groundwater radon measurements in Algeria. J Environ Radioact 51:173–180CrossRefGoogle Scholar
  10. Avbovbo AA (1980) Basement geology in the sedimentary basins of Nigeria. Geol 8:323–327CrossRefGoogle Scholar
  11. Badhan K, Mehra R, Sonkawade RG (2010) Measurement of radon concentration in ground water using RAD7 and assessment of average annual dose in the environs of NITJ, Punjab, India. Indian J Pure Appl Phys 48:508–511Google Scholar
  12. Barnet I, Pacherova P, Neznal M (2008) Radon in geological environment—Czech experience Czech Geological Survey Special Papers, No. 19, Prague, pp 19–28Google Scholar
  13. Bayowa OG, Olorunfemi MO, Akinluyi FO, Ademilua OL (2014) Integration of hydrogeophysical and remote sensing data in the assessment of groundwater potential of the basement complex terrain of Ekiti State, Southwestern Nigeria. Ife J Sci 16(3):353–363Google Scholar
  14. Cabral Pinto MS, Ferreira da Silva EA, Silva MMVG, Dinis PA (2014) Estimated background values maps of uranium in Santiago Island topsoil and stream sediments. Proc Earth Planet Sci 8:23–27CrossRefGoogle Scholar
  15. Choubey VM, Ramola RC (1997) Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India. Environ Geol 32(4):258–262CrossRefGoogle Scholar
  16. Choubey VM, Bist KS, Saini NK, Ramola RC (1999) Relation between soil gas radon variation and different lithotectonic units, Garhwal Himalaya, India. Appl Radiat Isot 51(5):587–592CrossRefGoogle Scholar
  17. Choubey VM, Bartarya SK, Ramoula RC (2003) Radon in groundwater of eastern Doon valley, Outer Himalaya. Radiat Meas 36:401–405CrossRefGoogle Scholar
  18. Cinelli G, Tositti L, Capaccioni B, Brattich E, Mostacci D (2015) Soil gas radon assessment and development of a radon risk map in Bolsena, Central Italy. Environ Geochem Health 37:305–319CrossRefGoogle Scholar
  19. Duenas C, Fernandez MC, Carretero J, Liger E, Canete S (1999) 226Ra and 222Rn concentrations and doses in bottled waters in Spain. J Environ Radioact 45:283–290CrossRefGoogle Scholar
  20. EU (2001) European Commission recommendation of 20th December 2001 on the protection of the public against exposure to radon in drinking water, 2001/982/Euratom, L344/85Google Scholar
  21. Hakonson-Hayes AC, Fresquez PR, Whicker FW (2002) Assessing potential risks from exposure to natural uranium in well water. J Environ Radioact 59(1):29–40CrossRefGoogle Scholar
  22. Hasan AK, Subber AR, Shaltakh AR (2011) Measurement of radon concentration in soil gas using RAD7 in the environs of Al-Najaf Al-Ashraf City-Iraq. Advances Appl Sci Res 2(5):273–278Google Scholar
  23. Hsu KC, Yeh HF, Chen YC, Lee CH, Wang CH, Chiu FS (2012) Basin-scale groundwater response to precipitation variation and anthropogenic pumping in Chihben watershed, Taiwan. Hydrogeol J 20:499–517CrossRefGoogle Scholar
  24. Isinkaye MO (2013) Natural radioactivity levels and the radiological health implications of tailing enriched soil and sediment samples around two mining sites in Southwest Nigeria. Radiat Prot Environ 36(3):122–127CrossRefGoogle Scholar
  25. Isinkaye MO, Ajiboye Y (2017) Assessment of annual effective dose due to radon concentrations in deep and shallow wells within Ekiti State. Nigeria Radioprot 52(3):167–170CrossRefGoogle Scholar
  26. JICA (2014) The project for review and update of Nigeria national water resources master plan, vol 2. Japan International Cooperation Agency (JICA report)Google Scholar
  27. Jönsson G, Baixeras C, Devantier R, Enge W, Font LL, Freyer K, Ghose R, Treutler HC (1999) Soil radon levels measured with SSNTD’s and the soil radium content. Radiat Meas 31(1):291–294CrossRefGoogle Scholar
  28. Kozlowska B, Hetman A, Dorda J, Zipper W (2001) Radon-enriched spring waters in the South of Poland. Radiat Phys Chem 61:677–678CrossRefGoogle Scholar
  29. Krishan G, Rao MS, Kumar CP, Semwal P (2015) Radon concentration in groundwater of east coast of West Bengal, India. J Radioanal Nucl Chem 303(3):2221–2225Google Scholar
  30. Lakovleva VS, Ryzhakova NK (2003) Spatial and temporal variations of radon concentration in soil air. Radiat Meas 36(1–6):385–388CrossRefGoogle Scholar
  31. Li X, Li G, Zhang Y (2014) Identifying major factors affecting groundwater change in the North China Plain with grey relational analysis. Water 6(6):1581–1600CrossRefGoogle Scholar
  32. Mittal S, Rani A, Mehra R (2016) Radon levels in drinking water and soil samples of Jodhpur and Nagaur districts of Rajasthan, India. Appl Radiat Isot 113:53–59CrossRefGoogle Scholar
  33. NGSA (2006) The geological map of Nigeria. Published by Nigeria Geological Survey Agency (NGSA), AbujaGoogle Scholar
  34. NIS (2007) Nigerian Industrial Standard NIS 554: 2007. Nigerian standard for drinking water qualityGoogle Scholar
  35. Okwoli E, Onoja OS, Udoeyop UE (2014) Ground Magnetic Electrical Resistivity Mapping for Basement Structures over Charnokitic Terrain in Ado-Ekiti, Southwestern Nigeria. Int J Sci Tech 3(10):683–689Google Scholar
  36. Oladapo MI, Ayeni OG (2013) Hydrogeophysical investigation in selected parts of Irepodun/Ifelodun local government area of Ekiti State, Southwestern Nigeria. J Geol Mining Res 5(7):200–207CrossRefGoogle Scholar
  37. Otwoma D, Mustapha AO (1998) Measurement of Rn-222 concentration in Kenyan groundwater. Health Phys 74(1):91–95CrossRefGoogle Scholar
  38. Oyinloye AO (2011) Geology and geotectonic setting of the basement complex rocks in South Western Nigeria: implications on provenance and evolution. In: Earth and environmental sciences. InTech PublicationsGoogle Scholar
  39. Pfanz H, Yüce G, Gulbay AH, Gokgoz A (2018) Deadly CO2 gases in the Plutonium of Hierapolis (Denizli, Turkey). Archaeol Anthrop Sci.
  40. Prasad G, Prasad Y, Gusain GS, Ramola RC (2008) Measurement of radon and thoron levels in soil, water and indoor atmosphere of Budhakedar in Garhwal Himalaya, India. Radiat Meas 43:375–379CrossRefGoogle Scholar
  41. Singh J, Singh H, Singh S, Bajwa BS (2008) Estimation of uranium and radon concentration in some drinking water samples. Radiat Meas 43:523–526CrossRefGoogle Scholar
  42. Somashekar RK, Ravikumar P (2010) Radon concentration in groundwater of Varahi and Markandeya river basins, Karnataka State, India. J Radioanal Nucl Chem 285(2):343–351CrossRefGoogle Scholar
  43. Tabar E, Kumru MN, Ichedef M, Sac MM (2013) Radioactivity level and the measurement of soil gas radon concentration in Dikili geothermal area. Turkey Int J Radiat Res 11(4):253–261Google Scholar
  44. UNICEF (2012) Technical Specifications and Procedures for drilling and construction of boreholes for hand pump programme. Document 2, UNICEF, Zimbabwe. January 2012Google Scholar
  45. United Nations Scientific Committee on the Effect of Atomic Radiation (2000) Sources and effects of ionizing radiation. Report to General Assembly with Scientific Annexes. United Nations, New YorkGoogle Scholar
  46. UNSCEAR (2008) United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation: Report to the General AssemblyGoogle Scholar
  47. US-EPA (United States-Environmental Protection Agency) (2016) A citizen’s guide to radon: the guide to protecting yourself and your family from radon, EPA 402/K-12/002/ 2016/ Available at:
  48. Vázquez-Suñé E, Sánchez-Vila X, Carrera J (2005) Introductory review of specific factors influencing urban groundwater, an emerging branch of hydrogeology, with reference to Barcelona, Spain. Hydrogeol J 13(3):522–533CrossRefGoogle Scholar
  49. WHO (2004) World Health Organization Guidelines for drinking-water quality, Third edn. vol 1. Recommendations, GenevaGoogle Scholar
  50. William FR, Steck DJ, Smith J, Brus CP, Fisher L, Neuberser JS, Platz CP, Robinson RA, Woolson R, Lynch CF (2000) Residential radon gas exposure and lung cancer. Am J Epidemio 151:1091–1102CrossRefGoogle Scholar
  51. Xinwei L (2006) Analysis of radon concentration in drinking water in Baoji (China) and the associated health effects. Radiat Protect Dosim 121(4):452–455CrossRefGoogle Scholar
  52. Yuce G, Gasparon M (2013) Preliminary Risk Assessment of Radon in Groundwater: A case study from Eskisehir, Turkey. Isot Environ Health Stud 49(2):163–179CrossRefGoogle Scholar
  53. Yuce G, Ugurluoglu D, Dilaver AT, Eser T, Sayin M, Donmez M, Ozcelik S, Aydin F (2009) The effects of lithology on water pollution: Natural radioactivity and trace elements in water resources of Eskisehir Region (Turkey). J Water Air Soil Pollut 202:69–89CrossRefGoogle Scholar
  54. Yuce G, Fu CC, D’Alessandro W, Gulbay AH, Lai CW, Bellomo S, Yang TF, Italiano F, Walia V (2017) Geochemical characteristics of soil radon and carbon dioxide within the Dead Sea Fault and Karasu Fault in the Amik Basin (Hatay), Turkey. Chem Geol 469:129–146CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Y. Ajiboye
    • 1
  • M. O. Isinkaye
    • 2
    Email author
  • M. U. Khanderkar
    • 3
    • 4
  1. 1.Department of Mathematical and Physical SciencesAfe Babalola UniversityAdo-EkitiNigeria
  2. 2.Department of PhysicsEkiti State UniversityAdo-EkitiNigeria
  3. 3.Center for Radiation Sciences, School of Healthcare and Medical SciencesSunway University47500 Bandar Sunway, SelangorMalaysia
  4. 4.Department of PhysicsUniversity of MalayaKuala LumpurMalaysia

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