Abstract
Natural radioactive materials under certain conditions can reach hazardous radiological levels. Therefore, it becomes necessary to study the natural radioactivity levels in soil to assess the dose to the population in order to determine the health risks and to obtain a baseline for future changes that may occur due to human activities. The motivation for this study was the devastating civil war that took place in Nigeria from 1967 to 1970, in which the study area was one of the battle fields. The results of our investigations of the soil in the metropolis of Ore show that the activity concentrations of 226Ra, 232Th and 40K in the soil vary from 14.21±1.40 to 25.87±1.01Bq/kg; 5.30±1.00 to 20.99±1.10Bq/kg and 58.01±1.80 to 382.98±3.00Bq/kg respectively. The total absorbed dose rate calculated from the activity concentrations of 226Ra, 232Th and 40K ranged from 15.42±1.10 to 40.99±1.36 nGy/h. The radium equivalent activity (Req) and the annual effective dose rates were also calculated and found to vary from 33.39±2.44 to 85.07±2.96 Bq/kg and from 18.91±1.35 to 50.27±1.69 µSv/y respectively. These values were found to be within the same range as recommended values (UNSCEAR, 2000). The study also indicated that 137Cs detected at three locations is an indication of the presence of artificial radionuclides which can be linked to the war that took place in the ancient town of Ore.
Highlights
The knowledge of radionuclide distribution and radiation levels in the environment is important for assessing the effects of radiation exposure due to terrestrial, cosmogenic and human activities
The total absorbed dose rate calculated from the activity concentrations of 226Ra, 232Th and 40K ranged from 15.42±1.10 to 40.99±1.36 nGy/h
The objective of this study is to evaluate and map soil radioactivity concentrations as well as environmental outdoor gamma dose rates in Ore metropolis, Ondo State, South - Western Nigeria
Summary
The knowledge of radionuclide distribution and radiation levels in the environment is important for assessing the effects of radiation exposure due to terrestrial, cosmogenic and human activities. Radiation exposure can occur in two ways: from sources outside the body (external exposure) and from radioactive substances contained in the food or water consumed or in the air inhaled (internal exposure). The natural radioactivity in soil comes mainly from the series radionuclides headed by 238U, 232Th and from natural 40K. Some other terrestrial sources including those of the 235U series, 87Rb, 138La and 176Lu exist in nature but at such low levels that their contributions to the dose to humans are considered insignificant. The radiological implication of these radionuclides is due to the gamma-ray exposure of the body and irradiation of lung tissue from inhalation of radon and its progenies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
