Twenty soil and 25 sediment samples were collected from the banks and bottom of the River Nile in the surroundings of biggest cities located close to it. Natural radioactivity concentrations of Ra,Th and K have been evaluated for all samples by means of γ spectrometric analysis. The radioactivity levels of soil and sediment samples fall within the internationally recommended values. Nevertheless, high natural background radiation zones are detected in the Kafr El-Zayat region due to the presence of a fertilizer factory, and in the Rosetta region due to the presence of black sand deposits. The absorbed dose rate, the γ index and excess life time cancer risk are calculated. High values for some of the radiation health parameters are detected in the Kafr El-Zayat and Rosetta regions representing a serious problem to public health because the soil and sediment are used as constructing material for buildings. Furthermore, the isotope analysis of uranium for representative collected sediment samples via α spectrometry showed average specific activities of 18.7 ± 3.6, 0.087 ± 0.0038 and 18.6 ± 3.8 Bq kg for U,U and U, respectively. In general, these values confirm the balance in the isotopic abundance of U isotopes.
Radium isotopes can be analyzed by different analytical methods based on gamma spectrometric measurements or alpha spectrometry. An improved method was developed to determine radium isotopes from water using gamma spectrometry after radiochemical separation. The Radium was selectively extracted from acidified samples using co-precipitation procedure with iron hydroxide and followed by precipitation of radium as radium sulphate Ba(Ra)SO 4 . The precipitate Ba(Ra)SO 4 was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. 226 Ra and 228 Ra activities were measured using low-background gamma spectrometry in water samples. Radium was pre-concentrated from environmental samples by co-precipitation with BaSO 4 . The amounts of 226 Ra and228 Ra on the sample were obtained by gamma-ray spectrometry for the 351 keVγ-ray from 214 Pb and for the 911 keV γ-ray from 228 Ac, both in radioactive equilibrium with precursors, respectively. The accuracy, selectivity, traceability, applicability and Minimum Detectable Activity (MDA) of the technique were discussed. Also, the effect of physical and chemical characteristics of the water samples such as TDS, pH, soluble species, sulphate and bicarbonate that effect on the radium determination were taking into consideration. The method has been validated with a certified reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 70% -90% and recovery was 97% and 80% for 226 Ra and 228 Ra, respectively.
Technetium-99 is a radioactive isotope with a half-life of 2.13 × 10 5 year. 99 Tc is a significant contaminant of concern to the world. For this reason, a detailed understanding of technetium chemistry is essential for the protecting the public and the environment especially after increasing the various applications and uses of isotopes in the medical practices. Therefore, treatment of waste increases prior to the safe discharge to the environment or the storage. The sorption of technetium in the form of pertechnetate on a nano manganese oxide loaded into activated carbon has been investigated. Nano manganese oxide (NMO) was synthesized from manganese chloride and potassium permanganate by co-precipitation and forming a new composite by loading a nanoparticle into a modified activated carbon by different ratios. Modifications of activated carbons using different concentrations of HNO 3 (4 M, 6 M and 8 M) are used in prepared composites. Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to characterize the prepared composites. The adsorption of 99 4 TcO − anions from low level radioactive aqueous waste was examined using batch technique. Different parameters affecting on the adsorption process were studied for the removal of 99 4 TcO − . The results revealed that NMO/AC (4 M, 6 M and 8 M) has a high adsorption efficiency (93.57%, 90.3% and 90.3%) respectively compared to NMO and AC which have a lower adsorption efficiency (41% and 38.9%) respectively. Moreover, the adsorption isotherm belonged to Freundlich model, the adsorption data followed pseudo-second order model and the thermodynamic study indicated that the adsorption of 99 4 TcO − on Nano-composites was an exothermic and spontaneous process.
Liquid scintillation counting (LSC) is an adequate nuclear technique to determine radioactivity levels, as verified by this study for the determination of the gross alpha and beta activities of aqueous samples because of its simplicity and low associated cost comparison with other techniques. This paper discusses a new approach to the monitoring of gross alpha and gross beta activities in water. The method consists of using pulse decay discrimination (PDD) liquid scintillation counting LSC of 2 ml of the sample after conditioning with 12 ml of AB-Ultima Gold LSC cocktail, and PDD 139 condition. Different factors that affected on the counting efficiency were studied such as quench reaction, volume of sample, and type of vial. The gross alpha and gross beta particle activity measurement using 40 K and 243 Am with different activities concentration for efficiency determination. The calculated detection limits were 0.07 Bq/l and 0.12 Bq/l for gross alpha and gross beta respectively for 500 min measurements of samples produced by concentration of one liter of water.
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