@article{ijp2015364,
author={{John, OJO Taiwo and Joseph, GBADEGESIN Karonwi A.},
title={Terrestrial Radiation Doses from Selected Towns of Southwestern Nigeria},
journal={International Journal of Physics},
volume={3},
number={6},
pages={244--247},
year={2015},
url={http://pubs.sciepub.com/ijp/3/6/4},
issn={2333-4576},
abstract={The activity concentrations of natural gamma-emitting radionuclides 238U, 232Th and 40K in soils from 7 sampling sites each in Ondo and Lagos States, southwestern Nigeria have been measured by using a well calibrated Hyper Pure Germanium Detector (HPGe). The mean activity concentration values of 39.24¡À1.12, 52.86¡À1.40 and 445.02¡À12.24 Bq kg-1 for 238U, 232Th and 40K respectively were obtained for . Activity concentration values of 23.21¡À0.92, 22.84 ¡À 0.78 and 204.02¡À7.00 Bq kg-1 were recorded for 238U, 232Th and 40K respectively for . The results obtained were used to estimate the absorbed dose rates in outdoor air which was found to be in the range of 12.35¡À179.59 nGy h-1 for Ondo State and 5.91¡À83.29 nGy h-1 for Lagos State with an overall mean values of 67.50¡À1.86 nGy h-1 and 33.83¡À1.17 nGy h-1 respectively for the two States. The corresponding outdoor annual effective dose rates were estimated to be between 22.7 and 330.6 ¦ÌSv y-1 for and between 7.3 and 102.2 ¦ÌSv y-1 for assuming 30% and 20% occupancy factors for the two states respectively. The average outdoor annual effective dose rate for towns in Ondo State is 64.85 ¦ÌSv y-1 representing 92.64% of the world average value (70 ¦ÌSv y-1) given by UNSCEAR. However, the cities in have an average outdoor effective dose of 41.52 ¦ÌSv y-1 which is less than 60% of the world average value. The values of the collective effective dose as calculated from the outdoor annual effective dose rates were found to be 540858 and 273296 person-Sv for Ondo and Lagos States respectively.},
doi={10.12691/ijp-3-6-4}
publisher={Science and Education Publishing}
}