ORAL

SESSION: EnvironmentalWedAM-R5	6th Intl. Symp. on Environmental, Health, Policy, Legal, Management and Social Issues Related to Metals, Materials and Mineral Processing
Wed Oct, 25 2017	Room: Peninsula 2
Session Chairs: Ifije Ohiomah; Omeje Maxwell; Session Monitor: TBA

11:30: [EnvironmentalWedAM02] Keynote
Determination of 238U, 232Th and 40K in Selected Borehole Rock Samples in Abuja, Nigeria, using Neutron Activation Analysis and its Radiological Risk on Drillers
Omeje Maxwell¹ ; ¹Covenant University, Ota, Nigeria;
Paper Id: 209 [Abstract]

The inadequate access to public water supply in Abuja has forced more than 80 % of the population of about 5 million to drill private borehole. Drillers are not aware of rock radioactivity especially Abuja granitic rocks which varies with depth. The radioactivity of 238U and 232Th decay chains for the lithological rock samples could be at equilibrium considering the age as well as the isotopic mass proportion which is assumed to be equal to its natural isotopic. A new approach of using Neutron Activation Analysis (NAA) is adopted for this study with the aim of minimizing sample size as well as less counting rate to estimate the concentration in rock samples. Subsequently, the epithermal method for the decay chain of 238U was also used for 40K decay chain determination. The result was used to determine the radium equivalent index risk on drillers with a value of 400.63 Bqkg‒1 which is higher than 370 Bqkg‒1recommeded by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) by a factor of 1.08. This value of 400.63 Bqkg‒1 may pose hazard health risk on drillers with external hazard index of 1.1 which is higher than 1 recommended by UNSCEAR. The results of this analysis using NAA have indicated that the exposure level due to naturally occurring radionuclides was lower, but safety rules should be applied for the borehole drillers in Abuja and beyond.

SESSION: EnvironmentalWedAM-R5	6th Intl. Symp. on Environmental, Health, Policy, Legal, Management and Social Issues Related to Metals, Materials and Mineral Processing
Wed Oct, 25 2017	Room: Peninsula 2
Session Chairs: Ifije Ohiomah; Omeje Maxwell; Session Monitor: TBA

12:00: [EnvironmentalWedAM03]
Radioactivity due to Major Oxide Compositions in Lithological Sequence Rocks of Abuja, North Central Nigeria
Omeje Maxwell¹ ; ¹Covenant University, Ota, Nigeria;
Paper Id: 210 [Abstract]

Radioactivity and major oxides investigations on lithological rock samples were studied using HPGe and XRF to understand the geological provenience on subsurface structures at Dei-Dei and Kubwa area of Abuja. The activity concentrations at Dei-Dei borehole varies from 18.5 � 1.7 to 37.1 � 3.6 Bq kg‒1, 44.6 � 4.1 to 97.4 � 8.1 Bq kg‒1 and 253.5 � 31.3 to 1195.6 �151.2 Bq kg‒1 for 238U, 232Th and 40K. Kubwa lithologic layers activity concentrations for 238U, 232Th and 40K ranges between 14.7 � 1.2 to 51.8 � 4.9 Bq kg‒, 32.5 � 4.1 to 85.3 � 8.1 Bq kg‒ and 118.9 � 15.7 to 751.2 � 93.9 Bq kg‒1. XRF results revealed that the increase in of 232Th activity decreases the activity of 238U in the presence of SiO2, CaO, Al2O3, Na2O, and K2O. This study provides useful information on the lithology radioactivity and for radiological mapping of the basement coastal pollution