الفهرس | Only 14 pages are availabe for public view |
Abstract In the present work the gamma spectrometry technique has been utilized to detect the activity concentrations attributed to 40K and both uranium and thorium series. The measurements have been undertaken for soil and sediment samples in front of different cities(regions) along Rashid branch of the River Nile. The obtained results are relatively small compared with the values commonly assigned as the world average except that of the soil samples collected from Kafr- Elzayyat because they are close to a phosphate fertilizer plant which have higher concentration values for226Ra (108.6±1.86 Bq/kg) than the worldwide levels .Moreover, soil samples from Rashid coast along Rashid city have also high radioactivity levels of 226Ra(46±1.23 Bq/kg) and 232Th(61±1.4 Bq/kg).The corresponding values for sediment samples at Rashid coast are 93.85±1.4 Bq/kg for 226Ra and 112±1.78 Bq/kg for 232Th which are higher than the world recommended level 32 Bq/kg for the former and 45 Bq/kg for the later. These higher values are a consequence of the existence of the black sand along Rashid coast which is highly rich with natural radionuclides. Dose assessment and hazard indices criteria were calculated and discussed. from the calculations, it is found that the absorbed dose rate, annual effective dose, the external and internal hazard indices and the representative level index exceed the regular limits in particular at sampling locations along Rashid and Kafr- Elzayyat (coast). The precise analysis of some selected sediment samples by means of alpha spectrometric analysis reveals that the ratio of 234U/238U is nearly one indicating case of secular equilibrium between Chapter Four Conclusion 161 them. Also, The values of 235U activities were estimated and is equal to or less than 0.7 % of the total uranium. Finally, the obtained results may be used to collaborate in the development of the Rashid branch by taking into consideration the possible solutions such as preventing all types of wastes to be fall into the stream by different means and using advanced chemical methods for water treatment if there is a possibility for water to be affected by such pollution at certain regions. |