Assessment of naturally occurring 40K, 232Th and 238U and their associated radiological hazard indices in soils used for building in Ondo West Local Government Area, Southwestern, Nigeria

Abstract

The naturally occurring 40K, 232Th and 238U radionuclide contents in the soil used as building materials in Ondo West Local Government, Southwest Nigeria were determined using gamma spectrometric technique. The radiological hazards were estimated by employing several indices consisting of radium equivalent (Raeq), representative level index (RLI), activity utilization index (AUI), absorbed dose (D), annual effective dose, external hazard index (Hex), internal hazard index (Hin) and gamma index (Iᵧ). The average activity concentrations of 238U, 40K, 232Th and Raeq were 171.8, 146.2, 19.8 and 211. 3 Bqkg-1 while the average values of Hin, Hex, RLI, D, AED, ELCR, AUI and Iᵧ were, 1.0, 0.6, 0.2, 97.4, 0.5, 3.9 x 10-3, 1.8 and 0.7, respectively. The multivariate statistical analysis was employed to identify the relationships between the radionuclides and the estimated radiological hazard parameters. The estimated radiological indices were within the internationally acceptable limits confirming the safe use of these soil for building construction for human dwelling without any radiological implications.

Keywords

• natural radionuclide
• soil
• exposure
• radiological indices