Natural Radioactivity Measurements of Basalt Rocks in Aden governorate, South of Yemen on Gulf of Aden

The amounts of radioactivity in the igneous rocks have been investigated; 63 basalt rock samples were collected from Aden governorate, South of Yemen. The activity concentration of 226 Ra, 232 Th and 40 K were measured using NaI (TI) detector. Along the study area the radium equivalent activities Raeq in Bq/Kg of samples under investigation were found in the range of 51.60to 809.26Bq/Kg with an average value of 237.01Bq/Kg, this value is below the internationally accepted value of 370 Bq/Kg. To estimate the health effects of this natural radioactive composition, the average values of absorbed gamma dose rate D (55 nGyh -1 ), Indoor and outdoor annual effective dose rates Eied (0.11 mSvy -1 ), and Eoed (0.03 mSvy -1 ), External hazard index Hex(0.138) and internal hazard index Hin (0.154), and representative level index Iγr(0.386) have been calculated and found to be higher than the worldwide average values.