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

Abstract

The activity concentrations of naturally occurring radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) 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 ²²⁶Ra, ²³²Th and ⁴⁰K 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^-1and 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