Soil–Soybean Transfer Factor of Natural Radionuclides in Different Soil Textures and the Assessment of Committed Effective Dose

From three different soil textures (clay, silt and sand), 36 soil and soybeans samples were accumulated from the agricultural area of EL-Mynia governorate in Upper Egypt, between (27 degrees 36'19.44''N; 30 degrees 30'14.14'' E) and (28 degrees 48'28.45'' N; 31 degrees 00'32.27'' E). Soil textures were prepared by particle size distribution through a pipette method. Its radioactivity measurements were performed with a NaI (Tl) and 3 x 3 inch crystal. The transfer factor (TF) of natural radionuclides from soil to soybeans was calculated. The value of the TF for 226Ra in clay soil ranges from 0.27 +/- 0.03 to 0.42 +/- 0.05, in sandy soil it ranges from 0.21 +/- 0.02 to 0.57 +/- 0.07 and in silt soil it ranges from 0.25 +/- 0.03 to 0.53 +/- 0.06. The TF for 232Th in clay soil ranges from 0.22 +/- 0.03 to 0.90 +/- 0.12, in sandy soil it ranges from 0.21 +/- 0.03 to 1.00 +/- 0.13, while in silt soil it ranges from 0.25 +/- 0.03 to 0.88 +/- 0.12. The TF for 40K in clay soil ranges from 0.95 +/- 0.13 to 2.05 +/- 0.29, in sandy soil it ranges from 1.21 +/- 0.17 to 2.52 +/- 0.35 and in silt soil it ranges and from 1.01 +/- 0.14 to 1.46 +/- 0.26.The results show that the committed effective dose from soybean consumption is between 54.5 and 103.4 muSv y-1 assuming consumption of 20 kg y-1.