Terrestrial radioactivity of the Jabal Eghei area in southern Libya and assessment of the associated environmental risks

Activity concentrations of main terrestrial radioisotopes Ra-226, Th-232 and K-40 were measured in geological samples collected in Libyas Jabal Eghei area, in order to contribute to the establishment of a baseline map of the environmental radioactivity levels and to estimate the associated environmental risk to the population. Activity concentrations ranged from 22 to 5256 Bq kg(1) for Ra-226, from 11 to 221 Bq kg(1) for Th-232 and from 132.0 to 2304 Bq kg(1) for K-40. Using these results, representative risk factors were calculated: the total absorbed gamma dose rate in air (ranged from 25.5 to 2434.3 nGy h(1) with a mean value of 251.8 nGy h(1)), the radium equivalent activity (555281 Bq kg(1), with the mean value of 537 Bq kg(1)), external hazard index (0.14914.24, with a mean value of 1.451) and annual outdoor effective dose (31.32985.4 Sv, with a mean value of 308.9 Sv). Accordingly, the radiation risk is above the world average, mainly as the consequence of discovered uranium anomalies