Abstract:
This study was conducted to assess the natural radioactivity level and doses calculation in some areas in South Kordofan State. Samples were collected contain soil, rock and some crops from northern and eastern regions of South Kordofan State. Activity concentration of238U, 232Th, 40K and 137Cs has been measured by γ-ray spectroscopy equipped with high efficiency NaI (Tl). The average concentrations were 108.82, 98.03 and 1059.13Bq/kg for soil samples, 282.76, 142.79 and 1081.50 Bq/kg for rock samples and 12.70, 14.54 and 866.32 Bq/kg for crops samples for 238U, 232Th and 40K respectively, the concentration of 137Cs was found to be 7.32 Bq/kg this means very little contribution to the total exposure for crops samples. The obtained results were found to be relatively higher than those mentioned in UNSCEAR data publications for normal background areas.
Absorbed dose rate in air at a height of 1m from the ground was measured and calculated using four sets of dose rate conversion factors and the corresponding annual effective dose was estimated. On the average, the values obtained were: 153.76, 132.14, 139.14 and 153.65 nGyh-1 for soil samples, 262.27, 222.39, 233.94 and 261.98 nGy/h for rock samples, 50.79, 45.10, 47.60 and 50.63 nGy/h for crops samples, and annual effective dose are: 188.70, 162.17, 170.75 and 188.56 μSvy-1 for the soil samples, 321.87, 272.92, 287.10 and 321.52 μSvy-1 for rock samples and 62.33, 55.35, 58.41 and 62.32μSv/y for crops samples, respectively for DRCFs (SAITO, MCNP, GEANT and UNSEAR). These values lie within the areas of high background radiation.
