Natural Background Radiation and Associated Radiological Hazard in Yewa Metropolis of Ogun State, Nigeria

Olowofila O. Inioluwa & Dosunmu G. Oluwaseun, Volume 3 Issue 2, December 2022 Pages 106-115, Published: 2022-12-16

Abstract

Natural background radiation and associated hazard assessment was carried out in Yewa metropolis area. Twenty-five soil samples were collected from selected towns including Idogo, Ilaro, Itolu, Iweke, and Owode. The collected samples were analyzed by gamma ray spectrometry. The mean activity concentration of the radionuclides 226Ra, 232Th and 40K in soil samples collected were 12.9±3.38, 6.40± .37 and 91.45±4.63 Bq/kg, respectively for Idogo; 5.72±0.33, 0.71± 3.60 and 148.40 ± 7.82 Bq/kg respectively for Ilaro; 24.66 ± 2.75, 5.35 ± 1.32 and 80.97 ± 4.12 Bq/kg for Itolu; 7.91 ± 1.02, 4.42 ± 0.28 and 105.25 ± 5.36 Bq/kg for Iweke and 26.20 ± 3.25, 4.84 ± 0.29 and 61.68 ± 3.26 Bq/kg for Owode. The results from the study sites were lower than the world average values of 35 and 30 Bq/kg and 400 Bq/kg for 226Ra, 232Th, and 40K, respectively. The average absorbed dose rates at a height of one meter above the ground delivered to the general public of the study areas were all lower than the international average value of 60 nGyh-1. The average values of Ra equivalent (Raeq) for all the selected areas were found to be below the international average of 370 Bq/kg and the computed mean annual effective dose (AED) from the selected study area was below the safety limit of unity. The results showed that no hazardous radiological effects are posed to the populace in the vicinity of the investigated locations