Radiological evaluation of building materials used in Malumfashi, Katsina state, using gamma-ray spectroscopy analysis

Abstract

The activity concentrations of naturally occurring radionuclides ( 226 Ra, 232 Th and 40 K) in building materials (sand, cement, blocks, granite, and paints) used in the construction of buildings in Malumfashi local Government area of Katsina state, Nigeria were determined by means of a gamma-ray spectrometry system using Sodium Iodide thallium activated (NaI(Tl)) detector in a low background configuration. The average activity concentrations for 226 Ra, 232 Th and 40 K ranged from 17.07±4.98 to 50.72±6.74, 23.03±1.54 to 42.91±2.37 and 84.03±5.44 to 363.45±5.27 Bqkg -1 respectively. Except for block samples, all the samples mean activity concentrations were less than their respective world averages. The estimated absorbed gamma dose rate (D) ranged from 30.75±4.22 to 64.57±4.78 nGyh -1 and the outdoor annual effective dose equivalent (AEDE) varied from 0.038±0.004 to 0.06±0.0051 mSvy -1 ; these values are below the worldwide effective dose of 0.07 mSvy-1. The values of radium equivalent activity (Ra eq ), the external hazard index (H ex ) and the internal hazard index (H in ) for all the samples in the present work were lower than the accepted safety limit value of 370 Bqkg -1 . Keywords : Radionuclide, hazard indices, gamma-ray spectrometry, building materials, Malumfashi