Investigation of Natural Gamma Radioactivity Levels and Associated Dose Rates from Surface Soils in Ore Metropolis, Ondo State, Nigeria

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. Th and 40 K ranged from 15.42±1.10 to 40.99±1.36 nGy/h. The radium equivalent activity (R eq ) 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 . The study also indicated that 137 Cs 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.

Radiation exposure to dwellers due to naturally occurring radionuclides found in selected commercial building materials sold in Nigeria

“…For the conversion of -radiation emanating from 226 Ra, 232 Th, and 40 K, the facts of 0.436 nGy h À1 Bq À1 kg À1 for 226 Ra, 0.599 nGy h À1 Bq À1 kg À1 for 232 Th, and 0.0417 nGy h À1 Bq À1 kg À1 for 40 K were employed for estimation of D Ex . The conversion factors have been considered from literature of Beck, 1980;Akinloye, Isola, & Oladapo, 2012;Avwiri, Nte, & Olanrewaju, 2011;Qureshi et al, 2014. It has been reported by Akinloye et al (2012) that, " 137 Cs, 90 Sr, 87 Rb, 138 La, 176 Lu, and 235 U decay series have negligible contributions to the total dose emanating from the environment background.…”

“…The conversion factors have been considered from literature of Beck, 1980;Akinloye, Isola, & Oladapo, 2012;Avwiri, Nte, & Olanrewaju, 2011;Qureshi et al, 2014. It has been reported by Akinloye et al (2012) that, " 137 Cs, 90 Sr, 87 Rb, 138 La, 176 Lu, and 235 U decay series have negligible contributions to the total dose emanating from the environment background. The D Ex was estimated using Equation (3) as given by Usikalu and Akinyemi (2007).…”

A Study of Natural Radioactivity in Some Building Materials in Nigeria

“…(28,29) . This amount is equivalent to 1.5 nGyh −1 (30,31) . The radium equivalent activity values obtained from the present study varies from 116 to 274 Bq kg −1 .…”

Statistical Assessment of Radiation Exposure Risks of Farmers’ in Odo Oba, Southwestern Nigeria

“…7. 7The conversion factor of each of the three concentrations ( 238 U, 232 Th and 40 K) is based on the assumption that 370, 259 and 4810 (Bq kg -1 ) of 238 U, 232 Th and 40 K produce the same gamma radiation dose rate (OECD, 1979;Akinloye et al 2012;Qureshi et al 2014;Ravisankar et al 2016).The estimated external radiation hazard index in Odo Oba varies from 0,3 (S2, S4 and S6) to 0,9 (S9). The estimated average value of H Ext in Odo Oba is 0,6 ( Figure 7).…”

“…Agricultural practices are most eminence in the study area possibly due to the availability of water that Oba River provides. Among the researchers that have investigated on the radioactivity concentration emanating from subsurface and its risks include: Odunaike et al (2008), Gbadebo and Amos (2010), Akinloye et al (2012), Avwiri et al (2012), Chandrasakaran et al (2014, Qureshi et al (2014), Rafi que et al (2014, Usikalu et al (2014), (2017), Ademola et al (2015, Ravisankar et al (2015), Alzubaidi et al (2016), Adagunodo et al (2017b), Adagunodo et al (2018a) and(2018b).…”