Radionuclide Content of Sands Used for Construction in Kakamega County, Kenya and Associated Indoor Radon Diffusion Fluxes

Abstract

Studies have been carried out to determine the natural radioactivity in construction sand and their associated radiation hazard in the old gold mining belt of Kakamega County, Kenya. The radioactivity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were measured using a gamma ray spectrometer with a NaI(Tl) detector. The results of concentrations of naturally occurring radionuclides were as follows: ²²⁶Ra ranged from 36.79±8.89 to 185.21±5.89 Bqkg^-1, ²³²Th ranged from 322.38±2.56 to 158.92±7.95 Bqkg^-1and ⁴⁰K ranged from 322.38±16.12 to 960.53±48.03 Bgkg^-1. The radium equivalent activities and the radiation hazard index associated with the natural radionuclides were calculated. A computer program was developed and applied to estimate the diffused indoor radon concentration by solving a simple transport equation. The indoor radon was assumed to originate from the walls of a room constructed from sands rich in uranium minerals found in this region.

Keywords: Radioactivity; Radium; Thorium; Potassium; Building sand; Indoor radon