The influence of geology on terrestrial gamma radiation dose rate in Pahang state, Malaysia

Terrestrial gamma radiation dose (TGRD) rate measurements have been made in Pahang state, Malaysia. Significant variations were found between TGRD measurements and the underlying geological formations. In some cases revealing significant elevations of TGRD. The acid-intrusive geological formation has the highest mean TGRD measurement of 367 nGy h(-1). This is more than six times the world average value of 59 nGy/h(-1), while the quaternary geological formation has the lowest mean gamma radiation dose rate of 99 nGy h(-1). The annual effective dose equivalent outdoor to the population was 0.216 mSv. The lifetime equivalent dose and relative lifetime cancer risks for an individual living in Pahang state were 81 mSv and 4.7 x 10(-3) respectively. These values are more than two times the world average of 34 mSv and 1.95 x 10(-3) respectively.