A method validation for determining gross alpha-beta activity concentration in water samples using LSC.

Liquid scintillation counter (LSC), with its advanced spectrometry capabilities, the Quantulus 1220™, was used to determine gross α-ß measurements in 25 environmental water samples. The determination of gross α-ß emitters with the LSC method requires an accurate pulse shape analyzer (PSA) setting under various quenching conditions. External quenching parameter values were evaluated with americium and strontium standard solutions to look for the optimal PSA value. A PSA calibration curve was obtained and used to measure real samples. To validate a constructed PSA calibration curve, a test was performed using spiked samples with different standard solutions. The results of the same set of 25 water samples were verified by element specific separations followed by α-spectrometry. An acceptable correlation was obtained between the two techniques. In the case of LSC analysis, the results indicate a good PSA optimization. The method was found to be reliable, effective and very suitable for wide range measuring campaigns.

Environmental radioactivity of soils and sediments: Egyptian sector of the Nile valley.

The activity concentrations of natural 40K, 232Th, and 238U in 89 soil and 84 sediment samples collected over the entire Egyptian Nile River basin including the Nile delta are reported based on the results of epithermal neutron activation analysis. The average activity concentrations of 40K, 232Th, and 238U equal to 15.3 ± 6.6, 15.6 ± 11.1 and 220 ± 31 Bq/kg, respectively, are significantly lower than those reported for the Upper Continental Crust, World Average Sediments as well as World Average Soils, suggesting the presence of a considerable portion of mafic material, most probably originating from the Ethiopian High Plateau. Their average activity concentrations are statistically the same in soil and sediments, indicating that the Nile sediments and soil material are of the same origin. The main goal of this study was not only to estimate the radiological hazards but also to show the influence of sedimentary material transportable by the Blue Nile from the Ethiopian High Plateau. The different hazard indices like the radium equivalent, gamma index, external hazard as well as the internal hazard show a low radiological exposure either on direct contact or if local mud bricks are used in the construction of dwellings.