Average Activity Concentrations Of 238U Research Articles

Study on the behavior of radionuclides in geologic samples from fault zone, Gabal Um Hamd, southwestern Sinai, Egypt

The present study concerned with the activity concentrations of natural radionuclides (238U, 234U, 230Th, 226Ra, 232Th, 40K and, 235U) in ten sedimentary rock samples collected from fault zone, Gabal Um Hamd, southwestern Sinai, Egypt. These samples were investigated to study their behavior during a part of geologic time. The activity concentrations were measured using γ-ray spectrometry (HPGe detector). The investigated samples were analyzed for major oxides using the XRF technique. The results demonstrated high average activity concentrations of 238U, 234U, 230Th, 226Ra, 232Th, 40K and, 235U than the worldwide average values as reported by UNSCEAR 2008. Theil diagram showed that there are accumulation and leaching of uranium in some samples in the two sides of the fault zone. It is noticed that the ages of uranium depositions for the samples collected from the downthrown of the fault zone vary from 121.5 to 440.1 ky, while for the sample collected from the upthrown of the fault is 210.9 ky. The 230Th/232Th activity ratios range between 4.55 and 91.04 for downthrown samples and between 4.75 and 6.05 for upthrown samples which are smaller than 20 except for two samples, indicating a contamination of the samples by detrital 230Th. After subtraction of the detrital 230Th, the corrected ages for downthrown samples vary from 119.1 to 231.7 ky while for upthrown samples vary from 164.4 to 390 ky.

Quantification of radiological hazards associated with natural radionuclides in soil, granite and charnockite rocks at selected fields in Ekiti State, Nigeria

Assessment of activity levels of radionuclides that exist in soil, granite, and charnockite rock samples is very crucial because it exhibits an enhanced elemental concentration of uranium (U) and thorium (Th) contributing higher natural background activity than usual in the environment and it may cause health risk to human health through the external and internal exposure. This study determined the radioactivity levels of 238U, 232Th, and 40K radionuclides in soil, granite, and charnockite rock samples collected from selected fields in Ekiti State, Nigeria using Caesium iodide CsI(Tl) scintillation gamma spectrometer. It also evaluated indices of the radiological parameters consisting of radium equivalent activity (Raeq), absorbed dose rate (DR), annual effective dose equivalent (AEDE), internal hazard index (Hin), and excess lifetime cancer risk (ELCR). The calculated average activity concentrations of 238U, 232Th, and 40K are 30.40 ± 0.71 Bq kg−1, 3.31 ± 0.05 Bq kg−1, and 222.25 ± 14.72 Bq kg−1, respectively, which were lower than their respective world average values. Comparatively, potassium concentrations in these collected samples have a higher value than concentrations of uranium and thorium (40K > 238U > 232Th). All the evaluated values of the radiological parameters (except DR) of the appraised radionuclides were below the global permissible limits. The granite rocks, charnockite rocks, and soils from Ekiti State in Nigeria do not pose any hazardous risk to humans, but continued monitoring is necessary when these materials are used as building materials, which cause long-term radiation exposure.

Analysis of the radiological dose and hazards assessment around swampy agricultural soil in Keffi, Nasarawa State, Nigeria

The present study analyzes radiological dose and hazard around the swampy agricultural soil in Keffi Local Government Area of Nasarawa State, using determined activity concentration (AC) of 238U, 232Th and 40K obtained from swampy agricultural soil samples, systematically collected from Ten (10) sampled points. Samples collected were further analyzed using a sodium iodide detector for activity concentrations of 238U, 232Th and 40K. The average AC of 238U, 232Th and 40K were 26.73±4.64, 9.77±2.57 and 1115.52 ±67.43 Bq/kg, respectively. The gamma absorbed dose rate (Dabs) ranges from 6.37E-01 to 2.33E+01 nGy/hr with a mean value of 6.10E+00 nGy/hr. The annual effective dose equivalent (AEDE) ranges from 8.12E-03 to 2.97E-01 mSv/yr with an estimated mean value of 7.77E-02 mSv/yr. The annual gonadal dose equivalent ranges from 4.48E-02 to 1.72E+01 mSv/yr with a mean value of 4.49E-01 mSv/yr. The calculated radium equivalent activity ranges from 1.44E+01 to 4.49E+02 Bq/kg with a mean value of 1.18E+02 Bq/kg, which falls below the recommended standard value of 3.7E+02 Bq/kg. The external and internal hazard index ranges from 3.89E-02 to 1.21E+00 mSv/yr with a mean value of 3.20E-01 mSv/yr, and 3.90E-02 to 1.41E+00 mSv/yr with a mean value of 3.70E-01 mSv/yr. The gamma hazard index ranges from 5.24E-02 to 1.84E+00 mSv/yr with a mean value of 4.83E-01 mSv/yr. The activity utilization index ranges from 8.65E-02 to 1.34E+00 mSv/yr with a mean value of 3.82E-01 mSv/yr, excess life cancer risk (ELCR) for both adult and child was found to be 1.94E-01 and 2.72E-01, respectively, higher than the recommended world average value of 0.29E-03. The high value of ELCR implies that residents around the study area have a high chance of developing cancer over a lifetime. Hence periodic radiological dose and hazard analysis is recommended to keep the exposure as low as reasonably achievable.

Physicochemical and radiological characterization of flue gas desulfuration waste samples from Brazilian coal-fired power plants

Flue gas desulfurization (FGD) waste is an industrial by-product generated during the flue gas desulfurization process in coal-fired power plants. This by-product contain trace quantities of naturally occurring radionuclides and elements such as As, Ba, Co, Cr, Zn. The characteristics of FGD waste are important for its reuse and are mainly depend on the desulfurization process. In this work, two types of FGD materials collected from three coal-fired power plants using semi-dry and wet processes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XFR) and particle size analysis. The radioactive content of 238U, 232Th, 228Th, 226Ra, 228Ra, 210Pb and 40K and trace elements were also determined using Neutron activation analysis and Gamma-ray spectrometry. The major constituents for all samples were Ca, Si, S, Al and Fe. Wet FGD by-product presented also high magnesium content. The wastes contain mainly semi-hydrate calcium sulfite and calcium sulfate. The particle size of FGD from semi-dry process was lower than that from the wet process. The average activity concentration of 238U, 232Th, 226Ra, 210Pb, 228Ra, 228Th and 40K varied between were 50-71, 33-42, 28-52, 113-150, 26-33, 33-39, 161-390 Bq kg-1, respectively. According to the results of leaching and solubilization tests, FGD samples were classified as non-hazardous and non-inert. The obtained data are useful for evaluation of possible applications of FGD by-products.

Natural and artificial radioactive pollution in sediment and soil samples of the Bosphorus, Istanbul.

This study focused on the determination of natural (238U, 232Th, and 40K) and artificial (137Cs) radionuclide concentrations both in 55 sediment samples collected from various depths in the Bosphorus and 5 soil samples from the coastline of the Bosphorus, Istanbul, using gamma-ray spectrometry with an HPGe detector. The mean activity concentrations of natural 238U, 232Th, and 40K and anthropogenic 137Cs were determined to be 11.41 ± 0.21 Bq kg-1, 6.87 ± 0.16 Bq kg-1, 369.61 ± 3.41 Bq kg-1, and 6.54 ± 0.11 Bq kg-1, respectively, in the sediment samples. The average activity concentrations of 238U, 232Th, 40K, and 137Cs radionuclides in the soil samples were also measured to be 11.65 ± 0.18 Bq kg-1, 9.55 ± 0.15 Bq kg-1, 369.43 ± 3.09 Bq kg-1, and 4.57 ± 0.09 Bq kg-1, respectively. Radiological contour maps based on the activity concentrations of natural and artificial radionuclides in the sediment samples for the Bosphorus, Istanbul, were created. The total annual effective doses due to soil samples were calculated to be 34.58 μSv y-1.

Radiation doses due to smoking different types of tobacco leaves grown in Turkey.

The activity concentrations of 238U, 232Th, 40K and 137Cs radionuclides in 25 samples of tobacco leaves grown in Turkey have been measured using a high purity co-axial germanium detector. The measured activity concentrations for 238U ranged from 3.6 to 22.5Bqkg-1 with an average of 9.8Bqkg-1, for 232Th from 0.8 to 11.0Bqkg-1 with an average of 2.4Bqkg-1, and for 40K from 360.3 to 1,479.5Bqkg-1 with an average of 810.0Bqkg-1. The concentrations of 137Cs, the residue of fallout from the Chernobyl reactor accident, were found to range from 0.2 to 2.1Bqkg-1 with an average of 0.5Bqkg-1. The results indicate that the average activity concentrations of 238U and 232Th lie within the range of measured values worldwide, whereas for 40K the average was found to be higher. The average annual effective radiation doses from the inhalation of the corresponding tobacco smoke by an adult smoking 20 cigarettes per day was deduced to be 93.3 μSv y-1 for 238U, 193.2 μSv y-1 for 232Th, 5.6 μSv y-1 for 40K, and 292.1 μSv y-1 in total. The average annual effective dose from 137Cs was calculated to be 8.5 nSv y-1. The resulting average annual effective radiation doses of 0.3mSv due to the inhalation of natural radiation sources in tobacco were compared with studies worldwide and found much smaller than the worldwide average effective dose of 1.26mSv. It is concluded that smoking may contribute a non-negligible fraction to the annual effective dose depending on cigarette consumption and activity concentration in tobacco. This study is the first in which natural and anthropogenic radioactivity in tobacco in Turkey was measured. Therefore, it is considered as a baseline study. Further studies are needed to investigate the role of tobacco refinement in the observed reduction of 238U concentration of refined tobacco.

Health ecological risk assessment of natural radionuclides and heavy metals in some sediment at Red Sea coast, Egypt

ABSTRACT The main objective of this study was to evaluate the health and ecological risks of natural radionuclides and heavy metals based on 23 sediment and water samples collected from some sediment at the Red Sea Coast in Egypt. The studied area is characterised old harbour used for shipping and processing phosphate ore. The results revealed that Cd and Zn contents in some water and sediment samples exceeded the standard limit, their concentrations reached (0.027–0.09) mg/L in water and (4.5–236) mg/Kg in sediment samples respectively. While the other analysed trace elements Fe, Mn, Ni, pb and Cu remain below permissible limits. The estimated contamination degree varied from low to considerable while the ecologic risk indices revealed that sediment ranged 10.8 to 466.6 as from low to moderately contaminate with trace elements. The average activity concentrations of 238U, 232Th, and 40K were 3.4, 0.83 and 5.5 Bq/L in water and 63.5, 16.5 and 556 Bq/Kg in sediment samples which were below the recommended limits except for the activity concentrations of 238U and 40K in some water and sediment samples above the permissible limits. The total annual effective dose rates from the exposure pathway were 0.09 to 0.26 mSv y−1. The estimated excess lifetime cancer risk values for workers were slightly higher than that of the sediment world average.

Radium radioactivity in soil profiles following long term irrigation with high radioactivity fossil groundwater

High radioactivity in a relatively saline confined aquifer water in different locations of the Disi area (South East of Jordan) was reported by some authors who recommended further investigation on the impact of that water on irrigated soils. Five well water samples (jointly used for irrigation and drinking) and 28 surface and subsurface soil samples from five profiles were collected from that area for the purpose of this study. Selected mineralogical, chemical, and physical properties of the soil samples were determined. Mineralogical compositions of the 28 soil samples were identified using x-ray diffraction, x-ray fluorescence, and ICP-MS techniques. Determination of activity concentrations of 238U, 226Ra and 228Ra in the five well waters and 22 soil samples from 4 sites (including a native soil) were determined using γ-ray spectroscopy. The results showed low salinity levels of both soil and water samples and low clay and organic matter contents in all soil samples. Kaolinite and mica were the dominant clay minerals with Fe substituting Al in the octahedral layer of these minerals. The average activity concentration of 226Ra and 228Ra in the well-water samples were 0.31 ± 0.09 and 1.74 ± 0.12 BqL−1, respectively. Such a high specific activity could be ascribed to the water enrichment with 228Ra diffusing from 232Th-rich sandstone geologic strata. Average concentrations of 238U and 232Th in the soil samples (0–120 cm depth) were 1.48 ± 0.38 mg kg−1 and 4.78 ± 1.55 mg kg−1, respectively. High correlation between these two radionuclides (R2 = 0.90) indicated no specific enhancement of these two metals from external sources, especially through chemical precipitation from irrigation water. Average activity concentration of 238U, 226Ra, and 228Ra in the soil samples were substantially low (20.8 ± 5.6, 16.94 ± 4.48, and 20.7 ± 6.2 Bq kg−1, respectively). No particular changes were observed when comparing concentration or radioactivity of these radionuclides with depth of a given soil or between irrigated and native soil samples at comparable depths. This could lead to the conclusion that there was no appreciable precipitation or adsorption of these radioactive metals from the percolating irrigation water onto the sandy soil complex.

Radiological measurement of hazardous levels in construction tiles in Bungoma county, Kenya

Twenty (20) different local and imported tiles were sampled from major hardware’s in Bungoma. The samples collected were separately ground, sieved, through a 0.5mm mesh, dried at 110° C, weight and packed in a 200ml stoppered plastic bottles. The samples were stamped with identification numbers and kept for 30 days for secular equilibrium to be reached between the activity of 238U,232Th ,40K radium and their progeny. The average activity concentration of 238U, 232Th and 40K was found to be 109±5.48Bqkg-1, 11±0.55 Bqkg-1 and 1574±78.7 Bqkg-1 respectively.  The average absorbed dose rate was found to be 140±7.03 nGyh-1 which is higher than the worlds average value of 60 nGyh-1. The average radium equivalent was found to be 288±14.44 Bqkg-1 which is lower than the world limit value of 370Bqkg-1. External and internal hazard indices were found to be 0.70±0.03 msvy-1 and 0.80±0.04 msvy-1respectively. Therefore, the sampled tiles used in Bungoma county for construction has minimal radiological threat to population.

Natural radioactivity level in fly ash samples and radiological hazard at the landfill area of the coal-fired power plant complex, Vietnam

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of 238U, 226Ra, 232Th and 40K were 93, 77, 92 and 938 Bq kg−1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y−1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30 ×10−3, 4.26 ×10−3, 0.62 ×10−3, and 25.61 ×10−3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

Radiological baseline around the Barakah Nuclear Power Plant, UAE

Destructive and non-destructive analysis techniques were used to establish a radiological baseline around the Barakah Nuclear Power Plant area in Abu Dhabi, United Arab Emirates. The natural radioactivity concentrations of 238U (226Ra), 232Th and 40K were measured for shore, soil and bottom sediment samples, using gamma spectrometry with a high-purity germanium (HPGe) detector. Alpha spectrometry was used to measure the 234U/238U ratio for some selected samples using a silicon surface-barrier detector. The measured gamma activity concentrations in shore samples are much lower compared to those in soil and bottom samples. The average activity concentrations of 238U (226Ra) are 4.43 ± 1.12, 13.54 ± 4.16 and 4.73 ± 3.01 Bq/kg in shore, soil and bottom sediment samples, respectively. The corresponding values for 232Th are 1.68 ± 0.49, 8.31 ± 3.87 and 1.83 ± 1.67 Bq/kg, and those for 40K, are 106.30 ± 50.68, 349.72 ± 107.16 and 105.23 ± 130.14 Bq/kg. The 234U/238U activity ratios span a wide range from 0.59 to 2.24, indicating a system where the daughter/parent is out of secular radioactive equilibrium. The hazard parameters, radium equivalent and absorbed dose rates, showed low levels compared to the world average level reported by the UNSCEAR in 2000. The estimated activity concentrations in this study were lower than the world average values and lower than the levels reported in nearby countries.

Gamma Ray Spectrometric Analysis of Sand Samples from Selected Beaches along Kenyan Coastline.

In this study, the activity concentration levels of 238U, 232Th, and 40K in sand samples collected from Shanzu, Nyali, Kenyatta, Tiwi, Shelly, and Diani beaches selected along the Kenyan coastline were determined using a gamma ray spectrometer with a NaI(Tl) detector. The average activity concentrations of 238U, 232Th, and 40K in sand samples were analyzed as 87 ± 4, 98 ± 4, and 1254 ± 62 Bq/kg, respectively. Also, radium equivalent (Raeq) activity and internal (Hin) and external (Hex) hazard index were calculated to assess the radiological hazards associated with the use of sand samples as building materials. The average values of Raeq, Hin, and Hex were found as 327 ± 16 Bq/kg, 0.98, and 0.72, respectively. The average values of outdoor and indoor annual effective dose rates were estimated as of 0.23 and 0.63 mSv/y, respectively, which are below maximum recommended limit of 1 mSv/y. Generally, these results indicate no significant radiological health hazards for the studied beaches.

حساب تركيز النظائر المشعة الطبيعية والصناعية لنماذج تربة جنوب منطقة الدورة في محافظة بغداد، العراق

تم قياس وتحليل النشاط المحدد للعناصر المشعة الطبيعية والاصطناعية في تسع عينات للتربة في مواقع مختلفة من منطقة الدورة الجنوبية، محافظة بغداد، العراق باستخدام كاشف أشعة كاما NaI (Tl). تم العثور على متوسط تركيزات النشاط من 238U و232Th و40K و137C لتكون 38.22 بيكريل/ كغم و42.99 بيكريل/ كغم و16.64 بيكريل/ كغم و2.92 بيكريل/ كغم على التوالي. العديد من مؤشرات الخطر الإشعاعي بما في ذلك نشاط مكافئ الراديوم (Raeq) ، ومعدل الجرعة الممتصة (D) ، ومؤشرات الخطر الداخلية (Hin) والخارجية (Hex) ، الداخلية (AEDEin) والخارجية (AEDEex) المكافئ الفعال للجرعة السنوية ومؤشر أشعة كاما (Iγr) ) محسوبة. إن نتائج جميع مؤشرات الخطر الإشعاعي أقل من قيمها الدولية. تكشف هذه الدراسة أن معظم المواقع في منطقة الدراسة آمنة من أي مخاطر إشعاعية.

EFFECT OF WORKING CONDITIONS AND NATURAL RADIOACTIVITY LEVELS ON OCCUPATIONAL DOSES TO WORKERS OF AN OLD MANGANESE MINE.

The aim of this work was to use RESRAD-Build model to predict the resulting external and internal radiological doses received by the workers of manganese mine located in Southern Sinai. In order to achieve that goal, measurement of the activity concentrations of natural radionuclides in rock samples collected from the inside gallery of such mine, using hyper pure germanium (HPGe) detector. Radon gas concentrations were also measured. The average activity concentrations of 238U, 226Ra, 232Th, 40K and 210Pb in rock samples were 207.3, 155.5, 59.7, 304.5 and 119.3Bq kg-1, respectively. The average radon activity concentration was 1254.6 Bqm-3, which is equivalent to 0.135 WL. The radon concentration increases further as going deep inside the mine up to 6238 Bqm-3. RESRAD-Build model occupational effective dose equivalent (EDE) received by the workers, from natural radionuclides, dominated by 222Rn emanated from the parent nuclide 226Ra.There was good agreement between the occupational annual EDE calculated from the measured rock samples and that predicted by modeling, with estimated values of 83.8 and 82.1 mSvy-1, respectively. This radiological dose assessment indicated the predominance of internal pathways owing to radon decay products, in both cases (measured and modeled). The occupational radiological dose from the inhalation of radon and radon decay products resulted in a high lung cancer risk based on the current measurements and ventilation conditions within the mine.

A practical study to determine the percentage of radiation in medicinal herbs used in the Iraqi market

Some commonly used medicinal plants have been chosen to find out the radioactivity concentration and their annual effective dose for 10 samples, Because of that naturally arising radionuclides of 238U, 232Th and 40K., Have used Gamma ray spectroscopy was used to find activity concentrations and the results of the analysis indicated that the average activity concentration of 238U, 232Th and 40K in the medicinal plants, where the results was 38.12 ± 1.619 Bq kg-1, 12.95 ± 0.896 Bq kg-1 and 570.70 ± 31.453 Bq kg−1 correspondingly. Chamomile noted ha the greatest concentration of activity to the 238U and 40K Whereas the maximum concentrations of radioactivity for 232Th in Officinalis Borago were noted. The values of the radium corresponding mean (62.715) Bq.kg−1. (Outdoor and indoor absorbed dose, Outdoor annual effective dose equivalent, Indoor annual effective dose equivalent and Total annual effective dose equivalent). Where the effective committed annual dose value was less than the world average (0.3 for ingestion of probable radionuclides contained in the UNSCEAR 2000 report. Also Well we found a risk factor was (1.4325*10−5) significantly less than the ICRP cancer risk, all values were below the internationally allowed limits, the results provide baseline values that may be useful in developing radiation protection rules and regulations in addition to setting ideals and rules for the usage of therapeutic plants or herbal to the competent establishments.

Assessment of environmental radiation exposure from soil radioactivity around the Southern area of Chad

A study to ascertain the radioactivity levels of various radionuclides from soil samples collected in Chad using a high-resolution gamma ray spectrometry system is presented in this article. The activity concentrations are determined for the radionuclides:226Ra,214Pb,214Bi and228Ac,208Tl,212Pb following the decay of238U and232Th as well as40K,235U, and137Cs. The values of activity concentrations of238U,232Th, and40K in the soil samples ranged from 2 to 245, 2–40, and 20–454 Bq/kg, whereas235U and137Cs ranged from 0.8 to 21.7 and 0.3–3.8 (Bq/kg), respectively. In order to evaluate the radiological exposure of the natural radioactivity, the radium equivalent activity, external exposure index, internal exposure index, and annual effective-dose equivalent have been calculated which ranged from 27 to 465 (Bq/kg), 0.09–1.25, 0.13–2.38, and 0.09–1.65 (mSv/y), respectively. Correlation between238U versus232Th,40K versus238U, and40K versus232Th was investigated; the results showed good correlation for238U versus232Th and40K versus238U while40K versus232Th gives poor correlation. For the 20 samples collected and analyzed for this study, the results showed that average activity concentration of238U is relatively higher than the world average, while for both232Th and40K, it was relatively lower.

Radiometric and environmental impacts of mill tailings at experimental plant processing unit, Allouga, Egypt

Uranium mining and ore processing are known to be harmful to the environment and human health if the waste generated is not managed properly. The aim of the present study is to determine the radiological indices in the mill tailings and review the possible attempts to utilize and minimize its hazardous effect. The activity concentrations of natural radionuclides, 238U, 232Th, 226Ra, and 40K have been measured by gamma spectrometry using HP-Ge detector. The average activity concentrations of 238U, 232Th, 226Ra, and 40K in the tailings wastes were 2071.8, 59.92, 6921.262, and 445. 57 Bq/kg respectively which are higher than the international average limit. The ranges of hazard indices such as Radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), γ-radiation hazard index Iγ, Dose rate (nGy/h) and annual effective dose equivalent (AED), were estimated. Uraniumm isotopic ratios in the ore –material and mill tailing samples indicate migration out of radionuclides to the surrounding environment causing contamination and many dangerous diseases. Fairly, all investigated tailing waste samples do not satisfy the universal standards, the studied wastes relatively still have high uranium contents and need reprocessing.

Factors Controlling Natural Radionuclides Migration in Sedimentary Rock Samples, Gabal Um‐Hamd, Southwestern Sinai, Egypt

The activity concentrations of some radionuclides (238U, 234U, 230Th, 226Ra, 232Th, 40K and 235U) were measured by γ‐ray spectrometry in order to study their behavior and the relation between them in Carboniferous rock samples collected from Gabal (mountain) Um‐Hamd, southwestern Sinai, Egypt. The whole samples are located in the two limbs and trough of a synclinal form structure to identify the radionuclides migration processes which have occurred in these rock samples. The average activity concentrations of 238U, 232Th, 226Ra, and 40K measured in the all samples except sandy dolostone sample are higher than the worldwide average values as reported by UNSCEAR 2008. The activity ratios (234U/238U) for half of the samples are in equilibrium, while the other half samples are below unity indicates migration‐out of uranium. The hazard indices were also calculated. The variations in lithologic types and the configuration of the structural synform played its roles beside the physical and chemical properties of different radionuclides in their fractionations.

Sequential Radiochemical Procedure for Isotopic Analysis of Uranium and Thorium in Egyptian Monazite

Gamma and alpha spectrometry techniques were applied to determine the activity concentrations of 238U and 232Th (Bq kg–1) as well as the 234U/238U and 230Th/234U isotopic ratios for commercial grade monazite (purity ≈50%) supplied from the Egypt nuclear materials authority. A method for total dissolution of monazite followed by the sequential radiochemical separation using anion-exchange chromatography is presented. The average activity concentrations of 238U and 232Th, measured by α-ray spectrometry, are 2.49 g kg–1 (0.24 wt %) and 30.09 g kg–1 (3.1 wt %), respectively. The calculated 234U/238U and 230Th/234U isotopic ratios are close to unity, suggesting closed system equilibrium. The possibility of using leaching of monazite with water at different pH values for gaining information about the masses of uranium and thorium that pass into the solution and remain fixed in the crystal lattice was examined.

NATURAL RADIOACTIVITY ASSESSMENT AND THE ASSOCIATED RADIOLOGICAL HAZARDS FOR BEACH SAND, BALTIM AREA, EGYPT.

Natural radioactivity of 238U, 232Th series and 40K of black sand samples collected along El-Fanar and El-Nargess Beaches in Baltim area, north of the Nile Delta in Kafr El-Sheikh Governorate, were measured using a gamma-ray spectrometer with a high purity germanium (HPGe) detector. Results showed that the average activity concentrations of 238U and 232Th in El-Fanar Beach was significantly higher (73.22±5.1 and 70.8 ± 4.9 Bq kg-1) than El-Nargess Beach (31.91±2.2 and 25.95 ±1.8 Bq kg-1) respectively. The average activity concentrations of 40K in El-Fanar Beach was lower (67.47±4.7 Bq kg-1) than that in El-Nargess Beach (80.75±5.6 Bq kg-1). The hazard indices due to these radionuclides have been calculated. The obtained results from this study indicate that the average activity concentrations of 238U, 232Th and40K at El-Nargess Beach are within world median ranges while average activities of 238U and232Th in El-Fanar Beach are higher than the world mean (33and45) Bq kg-1 respectively. This study aimed to establish a baseline map of radioactivity background levels in the aforementioned region to assess any change in the radiological background levels due to any artificial effects attributed to any radiation activities.