Natural radioactivity measurements in the granite rock of quarry sites, Johor, Malaysia

Abstract

This study was conducted to determine the concentration of natural radionuclides in the granite rocks of selected quarry sites in Johor state, Malaysia and their possible radiological effects. The activity concentrations of 238U, 232Th and 40K in the areas of study indicated varying values of 238U, 232Th and 40K. The highest values of 238U and 232Th concentrations (67±1 and 85±2Bqkg -1, respectively) were observed at Kamad Quarry (IJM), whereas the highest value of 40K concentration (722±18Bqkg -1) was detected in Kim Seng Quarry, while the values of activity concentration are lower in Hanson Quarry Products (Kulai) (25±0.5 for 238U, 24±0.5 for 232Th and 429±11 for 40K). Overall, 40K has the highest concentration in the granite rocks of the quarry sites, followed by 232Th and the least for 238U. The radium equivalent activity concentration was found in the range between 94 and 239Bqkg -1, the absorbed dose rate was found to be in the range between 47 and 112nGyh -1, and effective dose ranged from 58 to 137µSvh -1. Moreover, the internal and external hazard index values were given in results lower than unity.