Natural Radioactivity in Locally Produced Building Materials in Ekiti State, Southwestern Nigeria

Abstract

Building raw materials and processed products can vary greatly in radionuclide contents depending on the character and the geology of the their origin. 160 samples of Brick block and 160 samples of Concrete block  for constructing dwellings were collected across the Ekiti State, Nigeria.  The activity concentrations of  ⁴⁰K, ²²⁶Ra and ²³²Th in the Brick block and Concrete block samples were determined by using gamma-ray spectrometry using a 7.62 cm × 7.62 cm NaI(Tl) detector of dimension, housed in a 6 cm thick lead shield.  The results show that the mean activity concentration values of  572.6 ± 175.9 Bq kg^-1,  47.9 ± 9.8 Bq kg^-1 and 63.8 ± 9.4 Bq kg^-1 for ⁴⁰K, ²²⁶Ra and ²³²Th respectively in concrete blocks are higher compared to the the mean activity concentration values 351.1 ± 3.1 Bq kg^-118.7 ± 6.2 Bq kg^-1 and 39.8 ± 3.5 Bq kg^-1obtained in brick blocks.  The absorbed dose rate, Annual dose equivalent, the external hazard and the qualification coefficients were determined. The radiological assessment values of the brick and concrete block building materials compare well with values found in literatures.  However,  the use of brick block and cement block materials for constructing buildings for human habitation in the study area  may pose a health risk to the population if there is no remediation by the regulatory body in the state

Keywords:             Brick-block, Cement, Concrete-block, Building, Radioactivity, Radionuclides,
Dose equivalent