Evaluation of Rock Radiation Hazards for Construction Applications in Parts of Southwestern Nigeria

Abstract

Geophysical investigation involving the radiometric method was carried out around some selected rock outcrops (finegrained granite (FGG), charnockite (CCK) and granite gneiss (GGN)) in Southwestern Nigeria to assess its natural radioactivity and radiation hazards. Three hundred and six (306) stations were occupied along six traverses varying from 200-300 m using gamma-ray spectrometer. The average elemental and activity concentrations for 40 K, 238 U and 232 Th are 2.85±1.08%, 3.08±0.46 ppm, 22.38±8.15 ppm and 892.72±337.83, 38.06±5.67, 90.84±33.09 Bq kg-1 respectively. Observed highest values of radioactivity concentration of 40 K, 238 U and 232 Th were 1190.01±605.65 (GGN 2), 46.88±25.75 (CCK 2) and 121.01±20.53 (CCK 1) Bq kg-1. Mean annual outdoor and indoor effective dose rates of 0.114 and 0.442 mSv y-1 , hazard indices of 0.639 mSv y-1 (Hex) and 0.742 mSv y-1 (Hin) are below the world stipulated standard. Thus, the rocks pose insignificant radiation hazards to people and are safe as construction materials. The elevated levels of annual gonadal dose equivalent (AGDE) and excess lifetime cancer risk (ELCR) of 777.485 µSv y-1 and 1.545×10-3 respectively suggest regular monitoring of radioactivity levels of geological materials from sources before their adoption in construction. Appropriate agency should be constituted to consistently monitor radiation and prevent associated health problems.

Investigation of Building Materials’ Radioactivity in a Historical Building—A Case Study

“…Activity utilization indices AUI ranged from 0.53 to 1.29, and were less than the recommended value (I ≤ 2). The AUI values in this study were comparable with those in the study by Ademila, 2020 [ 68 ].…”

Measurment of Natural Radioactivity and Evaluation of Radiation Hazards in Rock Samples of Seashore, Kanyakumari District

“…If radiological data about an environment had been accessible, many illnesses and diseases that might have been treated well instead would not have been assigned to other causes. (Omowumi Ademila et al, 2020). Since there is little information available on the radioactivity of rock samples in the Kanyakumari District, it is crucial to research.…”

Quantification of radiological hazards associated with natural radionuclides in soil, granite and charnockite rocks at selected fields in Ekiti State, Nigeria

“…Igneous rocks (granite and charnockite) are known to contain minerals that can trap naturally occurring radioactive elements like uranium and thorium. When these elements decay, they release radiation in the form of alpha, beta, and gamma particles [ 8 ]. Typical granite is chemically composed of 70–77 % silica (SiO 2 ), 11–13 % alumina (Al 2 O 3 ), 3–5% potash (K 2 O), 3–5% soda (Na 2 O), 1 % lime (CaO), 2–3% total iron, and less than 1 % magnesia (MgO) and titania (TiO 2 ) [ 9 ].…”