Radiation Protection Dosimetry Advance Access originally published online on May 29, 2009
Radiation Protection Dosimetry 2009 135(1):54-63; doi:10.1093/rpd/ncp095
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Radioactivity in drilled and dug well drinking water of Ogun state Southwestern Nigeria and consequent dose estimates
Department of Physics, Federal University of Technology, P.M.B. 704, Akure, Ondo State, Nigeria
* Corresponding author: ajayisam1089{at}yahoo.com
Received January 5, 2009, amended April 18, 2009, accepted April 29, 2009
Activity concentrations of 40K, 226Ra, 228Ac and 235U were measured in 11 dug and 9 drilled well water samples from 3 large cities in Ogun state, Southwestern Nigeria, consumed by the population living in the cities. The measurement was done using co-axial type high-purity germanium (HPGe) detector (Canberra Industries Inc.). The measured activity concentrations in the water samples ranged from 1.74 ± 1.83 to 4.69 ± 0.17 Bq l–1; 2.89 ± 0.62 to 7.79 ± 7.22 Bq l–1; 0.35 ± 0.07 to 1.17 ± 0.40 Bq l–1 and 0.18 ± 0.05 to 4.77 ± 0.34 Bq l–1 for 40K, 226Ra, 228Ac and 235U, respectively. Total annual effective dose rates from the ingestion of these radionuclides in the untreated wells were estimated using measured activity concentrations in the radionuclides and their ingested dose conversion factors. Estimated annual effective dose rates ranged from 0.04 to 6.82; 0.01 to 1.36 and 0.01 to 1.49 mSv y–1 for age groups <1, 2–7 and 
17 y, respectively. Committed dose for age group 17 y ranged from 8.8 x 10–4 to 8.9 x 10–2 Sv. The calculated annual effective dose values due to the ingestion of 226Ra in the Awujale, Ake, Saboab, Alagbon, Alapora and Totoro samples exceeded International Commission on Radiological Protection limit of 1.0 mSv y–1 for individual public exposure. These wells are recommended for treatment that would remove radium from their waters.