"(Assessment of Natural Radioactivity Levels and Rare Earth Elements in Gandula Area at Al –Gabale Al -Akhdar ( LIBYA)"

Abstract

The aim of this thesis is to evaluate the activity concentrations of naturally occurring in the environment associated with the 238U and 232Th decay chains and the long-lived natural occurring radionuclide40K in environmental samples. The samples were collected from different locations around Gandula region (norh eastran side of Libya) to elevate natural radioactivity. The analysis of the samples was done by using high purity germanium detectors (HPGe). The analysis demonstrates that the measured average activity concentrations for the soil samples of 226Ra, 238U, 232Th and 40K were 66.32, 59.52, 56.07 and 517.92 Bq.Kg-1,respectivly. While the average activity concentrations for rock samples of 226Ra, 238U, 232Th and 40K were 26.01, 23.39, 25.13 and 100.97 Bq.Kg-1, respectively. On the other side the average activity concentrations of plant samples are 106.22, 95.49, 143.22 and 1255.82 Bq.Kg-1 for the above elements, respectively. While the average cocentrations for water samples of 226Ra, 238U, 232Th and 40K are 19.24, 16.78, 19.32 and 102.78 Bq.L-1 respectively. It was observed that the highest activity concentration values determined among the soil, plant and water samples are higher than the worldwide average as reported by the UNSCEAR 2000. The radium equivalent activity (Raeq) in all samples were determined, we found in soil rock, plant and water samples are ranged between 125.65 to 233.51 Bq.Kg-1, 56.50 to 89.29 Bq.Kg-1, 244.05 to 754.01 Bq.Kg-1 and 44.01 to 60.26 Bq.Kg-1, respectively. The values of external hazard index, gamma radiation level index (Iγ), I- alpha (Iα) are close tounity for all samples under investegated. The value of the absorbed dose rate, annual effective dose and cancer risk factor in the all samples were also determined.