Natural radioactivity and radiological hazard assessment of modern wire-cut bricks from Tamil Nadu, India using NaI(Tl) gamma spectrometry

In this work, 36 wire-cut brick samples were collected from Tamil Nadu, India to determine the activity concentrations of 226Ra,232Th, and 40K using NaI(TI) gamma-ray spectrometry. They ranged from BDL to 112 Bq Kg−1, BDL to 101 Bq Kg−1, and 149–564 Bq kg−1, with mean values of 56, 63, and 293 Bq Kg−1, respectively. The average activity concentrations of 226Ra and 232Th were found to be greater than the world-recommended average values of 50 Bq Kg−1. To assess levels of radon, the associated radiological parameters such as radium equivalent activity (Raeq), dose rate (DRin), internal hazard index (Hin), excess lifetime cancer risk (ELCRin), annual gonadal dose equivalent (AGDE), and gamma index (Iγ), were calculated for brick samples. As seen from the results, mean Raeq (169 Bq Kg−1) and Hin (0.6) are found to be within the permissible safety limit given by UNSCEAR 2000. Of these, the mean value of ELCRin is twice that of the world average value. Moreover, multivariate statistical analyses such as Pearson correlation, principal component analysis and cluster analysis are performed to identify the major contributing radionuclides in the brick samples.