Studyingof Naturally 2

Fayoum University. Faculty of Science. Physics Department. Studying of Naturally Occurring Radionuclides for Some Environmental Samples and Its Hazardous Effects Thesis Submitted in Partial Fulfillment for the AWard of the Master Degree in Physics To Physics Department Faculty of Science Fayoum University By Nadia Abd El- Fatah Kotb El-Sayed Demonstrator- Radiation Protection Department Hot Labs-Egyptian Atomic Energy Authority 2014 Fayoum University. Faculty of Science Physics Department Approval Sheet Researcher Name Thesis Title Nadia Abd El-Fatah Kotb El- Sayed Studying of naturally occurring radionuclides for some environmental Samples and its hazardous effects Degree Master Degree in Physics (M.Sc) Date 2014 Supervisors 1- Prof. Dr. Abd-El Mohsen Mohamed Basha Physics Department Faculty of Science Fayoum University. 2- Prof. Dr. Tarek Mohamed Selime El-zakla Radiation Protection Department Hot Labs Egyptian Atomic Energy Authority. Acknowledgement I wish to express my sincere acknowledgment to Prof. Dr. Abd El-mohsen Mohamed Basha, Physics Department, Faculty of Science, Fayoum University for his supervision, valuable help and his advice which have rendered many difficulties surmountable together with his continuous fruitful discussion, guidance, and comments throughout this research program. It is my privilege to extend my gratitude to. Prof. Dr. Tarek Mohamed Selime El- Zakla, Radiation Protection Department, Egyptian Atomic Energy Authority for his supervision, guidance, valuable comments and persistent encouragements. Contents Page Acknowledgement Abstract I Chapter (1):Theoretical Basis 1. Introduction - 1.1 Occurrence and sources of radionuclides 1 1.1.1 Natural radioactive sources 1 1.1.1.1. Terrestrial radioactivity 1 1.1.1.2. Cosmogenic radioactivity 4 1.1.2. Artificial or (man-made) radioactive sources 4 1.2. Radionuclides of interest 6 1.3. Radionuclides of Specific Interest in Foods and the 7 Environment: 1.4. Pathways of radionuclides in the environment 8 1.5 Hazardous Radionuclides and their Impacts on human health 9 .1.6. 12 The concept of Secular Equilibrium 1.7 Gamma-ray spectroscopy 1.7.1. Assessments of radioactivity levels 13 13 Chapter Two: Review of Literature 2.1 Introduction 16 2.1.1. Survey of natural radioactivity 16 2.2.1.1. Radioactivity in lake 17 2.1.1.2. Radioactivity in rocks 18 2.1.1.3. Radioactivity in (vegetation- drinking water- food) 21 2.1.1.4. Radioactivity in some building materials 22 2.1.5. Radioactivity in soil, sediment, sand and water samples 24 Chapter Three: Materials and Methods 3.1. Materials 36 3.1.1. Chemicals and reagents 36 3.1.2. Radioactive isotopes 36 3.2. Sample collection 37 3.2.1. Site location 37 3.3. Instruments 39 3.3.1. High-resolution gamma –spectrosopic system 39 3.3.2. X-ray diffractometer 39 3.3.3. Thermogravimetric analysis (TGA) 40 3.3.4. Fourier transforms infrared spectroscopy 41 3.3.5. X-ray Fluorescence Technique 41 3.3.6. pH Meter 42 3.4. Experimental procedures and methods of calculation 42 3.4.1. Physical characteristics 42 3.4.2. Gamma spectrometric measurements 42 3.4.2.1. Sample preparation 42 3.4.2.2. Detector calibration 43 3.4.2.3. Counting procedures 45 3.4.2.4. Low level background gamma-ray spectrometers 46 3.4.2.5. Counting statistics 47 3.4.3. Dose assessment for soil samples 47 3.4.3.1. Radium equivalent activity 47 3.4.3.2. Gamma-absorbed dose rate 48 3.4.3.3. Effective dose rate 48 3.4.3.3. The external hazard index 48 3.5 Safety precautions 49 Chapter four: Results and discussion 4.1. Characterization of the studied samples 50 4.1.1. Determination of the thermal stability 50 4.1.2. X-ray diffraction spectra of samples 52 4.1.3. X-ray fluorescence of samples 54 4.1.4. Infrared spectroscopy of samples 55 4.2. Chemical and physical parameters in samples 57 4.2.1. pH measurements 57 4.2.2. Electrical conductivity 57 4.2.3. Bulk density and total porosity 58 4.3. Natural radioactivity in Qarun Lake samples 59 4.3.1. Radioactivity concentrations in water samples 60 4.3.2. Radioactivity concentrations in bottom sediment samples 61 4.3.3. Radioactivity concentrations in shore sediment samples 62 4.3.4. Radioactivity concentrations in soil samples 63 4.4. Transfer factor of 232 Th, 238U and 40K from sediment to water 67 4.5. Regression analysis of the data 69 4.6. Dose assessment of soil samples 71 4.6.1. Radium equivalent activity 71 4.6.2. Gamma-absorbed dose rate 72 4.6.3. Effective dose rate 72 4.6.4. The external hazard index 72 Conclusions References Arabic Summary 74 Abstract This study has been carried out mainly for the studying of natural radioactivity related to the the radionuclides of 238U series, 232Th series and 40K radionuclide in Qarun Lake located in the deepest part of El-Fayoum depression at the western desert, 70 Km South Cairo-Egypt. These study carried out to assess the basline of radioactivity, to provide background information on the levels and distribution of radiation doses in the cultivated land around the lake, to develop maps of the distribution of natural radioactivity which can be used as a reference maps for the distribution of natural radioactivity levels in any future studies or any other purposes. The water, bottom sediment and shore sediment samples collected from Qarun Lake and soil collected from cultivated lands at the south of Qarun Lake. A lot of physical and chemical characteristics carried on these samples. For water samples the PH and electrical conductivity were measured. In the collected samples, the specific activities of 238U series, 232Th series and 40K (Bq/kg) were measured using gamma ray spectrometer based on HPGe detector. For soil, bottom sediment and shore sediment samples thermal analysis was measured using differential thermal analyser (DTA) and thermogravimetry (TG). XRD diffraction was measured using X-ray diffractometer. FT-IR analysis was measured using Fourier transform infrared spectroscopy. X-ray fluorescence was measured using X-ray florescence spectrometry. Total organic matter, particle size distribution, density and porosity were measured. The mean specific activities of 238U series, 232Th series and 40K in the bottom sediment samples ranged from 7.06±0.28 to 30.15±1.8 Bq/Kg with an average value 20.37Bq/kg for 238U and it ranged from 5.9±0.14 to 20.35±1.01 with an average value 14.18 for 232Th.it ranged from 68.06±2.01 to 351.88±4.82 with an average value 244.68 for 40K. The activity concentrations (Bq/L) for water samples ranged from 0.18 ± 0.03 to 3.53 ± 0.21 with an average value 2.19 for 232Th. The activity ranged from 0.95 ± 0.01 to 6.57± 0.26 with an average value 2.92 for 238U and ranged from 1.03 ± 0.04 to 43.74 ± 2.74 with an average value 16.12 for 40K. I The activity concentrations (Bq/kg) of shore sediment samples ranged from 1.43 ± 0.07 to 10.02 ± 1.61 with an average value 3.14±0.07 for 232Th, also the activity ranged from 2.32 ± 0.84 to 13.08 ± 1.74 with an average value 4.59±1.36 for 238U and ranged from 12.39 ± 3.62 to 80.75±7.35 with an average value 45.94 for 40K. The activity concentrations ( Bq/kg) for the cultivated agriculture soil samples ranged from 3.29 ± 0.90 to 18.52 ± 2.67 with an average value 11.47±2.13 for 232 Th ,while ranged from 3.51 ± 0.79 to 18.65 ± 5.1 with an average value 11.26±1.95 for 238U , and the activity ranged from 45.85 ± 2.60 to 350.35 ± 1.09 with an average value 313.98±3.02 for 40K. For dose assessment the radiological hazard indices were measured for the soil samples collected from the cultivated land. II Chapter (I) Introduction 1. Introduction Since the bombing of Hiroshima and Nagasaki (1945) and the Chernoby1 Catastrophe (1986), atomic energy became a symbol of power and evil. Radiation also, became a part of our physical world fact of everyday life. The natural sources of radiation in environment are responsible for some background radiation (Liesel, 2005). The major sources of external gamma radiation are K-40, uranium-238, thorium-232 and their decays products. The artificial radionuclides are those which are produced as a result of nuclear weapon tests and as by products from nuclear fuel cycle and other from mining, milling, fuel enrichment, fuel preparation for reactor use, and plant operation disposal (Thorne, 2003). 1.1. Occurrence and Sources of Radionuclides We live with radioactive radiation every day. Depending on the origin of the radiation one can distinguish between natural radioactive sources as well as manmade sources. 1.1.1 Natural radioactive sources The list of isotopes that contribute to natural radiation can be divided into those materials which come from the ground (terrestrial radioactivity) and those which are produced as a result of the interaction of atmospheric gases with cosmic rays (Cosmogenic radioactivity). 1.1.1.1. Terrestrial radioactivity Terrestrial radioactivity in the crust of the earth came into existence with the creation of the planet. Although some have long disappeared to levels that are not 1 detectable anymore, some radioisotopes take a long time to decay (on the order of hundreds of millions of years), they are still present today. The naturally occurring radioactive elements are almost exclusively members of one of four radioactive series that all begin with very long-lived parents that have half-lives of the order of the age of the earth (Podgoršak, 2005).The four naturally occurring series are named as follows: 1-Uranium series: The parent radionuclide in this series is 238 U (abundance =99.28%), which undergoes α decay with a half-life 4.47×109 y. The stable product of the uranium series is 206Pb, which is reached after 8α and 6β-decay steps. By far, the major form of natural radiation is radon gas. Radon-222 is a naturally occurring decay product of uranium-238 which is commonly found in soils and rocks. Radon-222 is a gas which is odorless, colorless, tasteless and chemically nonreactive. As it escapes from the soils and rocks of which it is trapped, it enters the water we drink and the air we breathe. 2-Thorium series: This series has its origin radionuclides 232 Th, its abundance 100% with a specific activity 2.4×105dpm g-1, which undergoes α-decay with a half-life 1.41×1010y. The terminal nuclide in this decay series is the stable species this series, the transformation from the original parent 208 232 208 Th to the final product pb requires 6α and 5β-decays. The long-lived intermediate is 6.7y for 2 pb. In 228 Ra Fig.1.1 shows the radioactive decay in thorium -232 and uranium-238 series. Fig.1.1 : The radioactive decay in thorium -232 and uranium-238 series. 3-Actinium series: The actinium series begins in nature with its longest-lived nuclide ends with the stable lead isotope 235 U, and 207 pb. Uranium-235 is an alpha-emitter with a complex alpha spectrum and a correspondingly complex gamma spectrum. The immediate decay product of 235 U is 231 Th (t1/2=26.64h). Thorium-231 is a beta- emitter with a complicated decay scheme (Ivanovich & Harmon, 1992). 4-Neptunium series: The name comes from the longest lived nuclide 237Np which is considered as the parent species, it has a half-life of 2.14 × 106 yr. The end product of the neptunium series is 209 Bi, which is the only stable isotope of bismuth. 7α and β- decays are required in the sequence from the parent 237 Np to 209 nuclide in the neptunium decay series is the uranium isotope 3 Bi. An important 233 U, which has a half-life of 1.59×105y .It is fissionable by slow neutrons (Choppin et al., 1995). Potassium- 40 is another major source of terrestrial sources .The long half-life of K-40 (1.25 billion years) means that it still exists in measurable quantities today. It beta decays, mostly to calcium-40, and forms 0.012% of natural potassium. It is found in many foodstuffs (bananas for example), and indeed fills an important dietary requirement, ending up in our bones. (Humans have about 65 Bq/kg of K40 and along with those foods are therefore correspondingly radioactive to a small degree. A 70 kg person has 4400 Bq of K-40 and 3000 Bq of carbon-14(Emsly, 1992). 1.1.1.2. Cosmogenic radioactivity It is formed as a result of interactions between certain gases in the Earth’s atmosphere and cosmic rays. Cosmic rays bombard the earth's upper atmosphere and collide with atoms such as nitrogen. The most important radionuclide produced is 14C. However, many others, such as 3H, 22Na, and 7Be, occur (Ajtić et al., 2008). Carbon-14 produced in the atmosphere is quickly oxidized to CO2. The equilibrium concentrations of 14C in the atmosphere are controlled primarily by the exchange of CO2 between the atmosphere and the ocean. The dangerous of cosmic rays represented in the production of 14C which merges with the nucleus of a living cell in humans, as well as affect the bone and bone marrow. 1.1.2. Artificial or (man-made) radioactive sources These are the artificial radionuclides, which are produced as a result of nuclear weapon tests and as byproducts from: nuclear fuel cycle and other from mining, milling, fuel enrichment, fuel preparation for reactor use, plant operation 4 disposal, and the use of radioisotopes in agriculture, industry, research, and medicine. The difference between man-made sources of radiation and naturally occurring sources is the place from which the radiation originates. The following information briefly describes some other examples of man-made radiation sources: 1-Medical radiation sources: x- rays are identical to gamma rays; however, they are produced by a different mechanism. x- Rays are an ionizing radiation hazard. In addition to x- rays, radioactive isotopes are used in medicine for diagnosis and therapy. 2-Consumer products: such as static eliminators (containing polonium-210), smoke detectors (containing americium-241), cardiac pacemakers (containing plutonium-238), fertilizers (containing isotopes from uranium and thorium decay series), and tobacco products (containing polonium-210 and lead-210). 3-Atmospheric testing of nuclear weapons: as a results of fallout radiation from the past atmospheric nuclear bomb tests, during the 1950s and 1960s, many radioactive were produced into the atmosphere. These materials have been transported around the world and eventually fall back to the earth. A wide range of radioactive materials including: carbon-14, results from irradiation of the atmospheric nitrogen by neutrons resulting from the explosion, together with a number of outputs of nuclear fission, such as: 131I, 137Cs, 90Sr, 95Zr. 4-Industrial uses of radiation: include x-ray machines and radioactive sources (radiography) used to test pipe welds, bore-holes, etc. Most people receive little of any dose from these sources. As a whole, these sources of natural and man-made radiation are referred to as background radiation. 5 1.2. Radionuclides of Interest Although several hundred radionuclides are produced by nuclear explosions or are present in irradiated reactor fuel, only a limited number contribute significantly to human exposure. These would normally include fission products and activation products. Table.1.1 shows radionuclides reported to be present in air and deposition samples shortly after the Chernobyl nuclear power plant accident, including both fission products and activation products (EPA, U. S., 2010). Nuclide Major Half-life Nuclide Half-life Major decay decay H-3 12.35 a β I-131 8.021 d β,γ Sr-89 Sr-90 Zr-95 50.5 d 28.7 d 64.09 d β β β,γ I-133 Cs-134 Cs-136 20.3 h 754.2d 13.0d β,γ β,γ β,γ Nb-95 Mo-99 35.0 d 2.7476 d β,γ β,γ Cs-137 Ba-140 30.0 a 12.751d β β,γ Ru-103 39.272 d β,γ Ce-141 32.50 d β,γ Ru-106 Ag-110m 372.6 d 249.79 d β β,γ Ce-144 Np-239 284.45d 2.355 d β,γ β,γ Cd-115 Sb-125 2.2 d 1008.1d β,γ β,γ Am-241 Cm-242 432.0 a 162.94 d α,γ α Sb-127 Te-129m Te-131m 3.9 d 33.6 d 30.0 d β,γ β,γ β,γ Pu-238 Pu-239/240 Pu-241 87.70 a α 4 3 2.411 x 10 a/6.563 x10 a α , α 3 a 14.35 β 110 a Te-132 3.204 d β,γ Pu-242 3.735 x 105 a α Table.1.1 : Radionuclides present in air and deposition samples from the Chernobyl accident. Half-life is given in hours (h), days (d) and years (a). One year = 365.2 d. 6 1.3. Radionuclides of Specific Interest in Foods and the Environment: In regard to internal exposure from ingestion of food and water and to the contamination of environmental materials which are part of the immediate pathways leading to contamination of food, the most important radionuclides to be assessed following a release of radionuclides from a uranium-fuelled reactor to the environment are: Alpha emitters: 238 Pu, 239+240Pu, 241Am, 242Cm. Beta emitters: 89 Sr, 90Sr & tritium. Gamma emitters: 134Cs, 137Cs (137mBa), I31I. The levels of radionuclides in the environment and food have been extensively compiled by (UNSCEAR, 2008). In general, the radionuclides of major importance in the contamination of food and environmental samples (materials which are part of the pathways leading to food) are: Air 131 Water 3 H, 89Sr, 90Sr, 131I, 134Cs, and 137Cs. Milk 89 Meat 134 Other foods 89 Vegetation 89 Soil I, 134Cs, 137Cs. Sr, 90Sr, 131I, 134Cs, 137Cs. Cs, 137Cs. Sr, 90Sr, 134Cs, 137Cs. Sr, 90Sr 95Zr, 95Nb, 103Ru, 106Ru, 131I, 134Cs, 137Cs, 144Ce. 90 Sr, 134Cs, 137Cs, 238Pu, 239+240Pu, 241Am, 242Cm. . This group of radionuclides is most likely to be of concern in terrestrially produced foods. Biological concentration processes in fresh water and marine systems can result in very rapid transfer and enrichment of specific radionuclides. The radionuclides which enter such systems can in certain cases be rapidly 7 accumulated by plankton and algae. Many other radionuclides would be present in debris from a nuclear accident, and their potential contribution to human exposure depends on the type of accident and the conditions at the time of the accident. Since there are several types of fuel, the spectra of radionuclides that would be present in accidental releases could be somewhat different. 1.4. Pathways of radionuclides in the environment Some levels of radiation are naturally present in surface and ground water, but other degrees of radiation exposure come from contact with rocks and soil that have been contaminated with the artificially produced radionuclides mentioned above. Releasing of radionuclides in the environmental materials is part of the immediate pathways to commonly encountered hazardous radionuclides through accidents, poor waste disposal, or other means. Contamination of food and water sources can occur from dust transported by wind from uranium mine sites and waste deposits (Neves et al., 2008). 8 Fig.1.2 illustrates the major pathways of radionuclides to the human (Technical Reports Series No. 295, 1989). Meas Uncontrolled atmospheric release of radionuclides Fallout urement of Fallout (washout) Rain water Resuspention Run off Land Plants Uptake Irrigation Surface water Wash off Fish Deep soil Irrigation Ingestion Ground water Drinking water External exposure Ingestion Animal and its products Human Fig.1.2 : shows the major pathway of radionuclides to the human . 1.5 Hazardous Radionuclides and their Impacts on human health Natural sources of radioactivity are all around, and man-made radioactive materials are a vital part of medicine and industry. Exposure to some radiation, 9 natural or man-made, is inevitable. We live with radiation every day; therefore we must understand its risks. Radiation is known to cause cancer in humans. It can also cause other adverse health effects, including genetic defects in the children of exposed parents or mental retardation in the children of mothers exposed during pregnancy (EPA, U. S., 2007). Eighty percent of that exposure comes from natural sources of radon gas, the human body, outer space, rocks and soil. The remaining 20 percent comes from man-made radiation sources, primarily medical x-rays. Radioactive materials that decay spontaneously produce ionizing radiation, which has sufficient energy to strip away electrons from atoms (creating two charged ions) or to break some chemical bonds. Any living tissue in the human body can be damaged by ionizing radiation in a unique manner. When ionizing radiation strikes an organism’s cells, it may injure the cells. If radiation affects a significant number of cells, it can eventually lead to cancer. At extremely high doses, this type of exposure can cause death. In general, there is no safe level of radiation exposure (EPA, U. S., 2008). At Chernobyl, some 60 radionuclides were emitted from the reactor (Balonov, 2008), but only a few were considered to present serious health hazards to humans and animals. Immediately after the disaster, the main health concern involved radioactive iodine-131, with a short half-life (eight days), but it can be transferred to humans relatively rapidly from the air and through consumption of contaminated milk and leafy vegetables. Iodine becomes localized in the thyroid gland (EHP, 2010). Today, there is concern about contamination of the soil with strontium-90 (half-life approximately 30 years) occurs in the soil, food and water. It can be 10 deposited in bones and remain in the body for long periods. In addition, 90Sr could cause problems in areas close to the reactor, but at greater distances its deposition levels were low. Also, Cesium-137& 134 isotopes of cesium have relatively longer half-lives (134Cs has a half-life of 2 years while that of 137 Cs is 30 years). These radionuclides cause longer-term exposures through the ingestion pathway and through external exposure from their deposition on the ground. It can be ingested or inhaled and locates in muscle tissue, bones and fat. The geochemical characteristics of this radionuclide are fairly similar to those of nonradioactive 55 Cs; therefore, 137 Cs released into the atmosphere becomes strongly adsorbed by clay minerals and also by organic matter in soils. It has received particular attention in the marine environment due to its long environmental half-life, high radiotoxicity and easily assimilated by animal and plant tissues. It usually presents as simple cations with high solubility and mobility in marine environments, depending particularly on the sorption of 137 Cs to sediment surfaces (El-Reefy, 2004). Uranium mining and the use of nuclear reactors are common sources of radionuclides, which are primarily contained within radioactive wastes, which present serious threats to human health. Additionally, Uranium has two primary isotopes 238U and 235U in the proportion of (99.3% to 0.7%) respectively. Although 235 U has a small environmental significance, it forms the basis of nuclear energy production. 238U has a greater number of decay products, several of which are longlived and it is more radiotoxic:  226Ra (Radium) is a member of the 238 U natural decay series, which has a half-life of 1600 years (Andrew and Dan Becker, 2010), and is the most 11 hazardous radionuclide released from uranium mining and milling. Chronic exposure to radium through the inhalation pathway can lead to leucopenia (a decrease in the number of white blood cells).  222Ra (Radon) comes from the natural decay of radium that is found in nearly all rocks and soils, which is a human lung carcinogen .It also causes the lung cancer death in uranium miners .Long-term exposure to radon leads to an elevated risk of leukemia (Yablokov ,2009). .1.6. The concept of Secular Equilibrium: For a radioactive decay series, such as the natural decay series, in which the parent is long-lived, compared to the daughters, equilibrium exists in samples that have been undisturbed for a very long period of time. The rate of decay of the parent is negligibly slow, that is, A1 (t) = λ1 N (t) ~ Ao (a constant) since the number of atoms of the parent does not change in time intervals comparable to the half-lives of the daughters. Thus, dN1 (t)/dt ~ 0. The number of first daughter atoms can decay away no faster than they are formed at the constant rate Ao, i.e., λ2 N2 (t) ~ λ1 N1= Ao. Thus dN2 (t)/dt~ 0. Similarly, the second daughter can decay away no faster than the rate it is formed by the decay of the first daughter (at the constant rate Ao, so that again dN2 (t)/dt ~ 0. This pseudo equilibrium called secular equilibrium continues down the decay chain for each daughter. Under secular equilibrium, we thus have for each radioactive member dN1 /dt ~ dN2/dt ~ ….dNn-1 /dt ~ 0. By setting each of the derivatives to zero in the decay equations, given by Eq. (1-11), we obtain λ1N1 = λ2N2= ….λn-1 Nn-1 (1-9) Or, equivalently, A0 = A1 = A2 =…. = An-1 12 (1-10) dNn(t)/dt = λn-1Nn-1(t) (1-11) Thus, under secular equilibrium, each member of the decay chain has the same activity. However, this very useful result applies only in samples that have been undisturbed for periods greater than several half- lives of the longest lived daughter. The daughters in samples of 238U obtained by extraction from ore are not in secular equilibrium (Kenneth Shultis and Faw, 2002). 1.7 Gamma-ray spectroscopy: There are a lot of methods and techniques applied in the determination of the naturally occurring radionuclide in the geological, biological and environmental media such as rocks, soil, air and natural wastewater. However, Quantitative gamma-ray spectroscopy is a powerful technique available for the nondestructive analysis of samples from such media (Yousef et al., 2007). 1.7.1. Assessments of radioactivity levels: Identification and assessment of low radioactivity levels in different samples emitting gamma rays by High purity Germanium detectors (HPGe) requires two types of calibration including, energy calibration and photopeak detection efficiency calibration. Energy calibration is necessary to identify different isotopes from respective gamma ray energy lines; while photopeak detection efficiency determination is necessary for quantitative assessment of the radioactivity levels for each radioisotope. 13 (a) Energy Calibration Energy calibration is simply to assign the correct energy value to the corresponding channel number. The pulse height is assumed to be proportional to the energy of the incident particle. This enables the linearly to find the energies of gamma lines emitted by unknown source. In gamma-ray spectroscopy with germanium detectors, the pulse height scale must be calibrated in terms of absolute gamma-ray energy if various peaks in the spectrum are to be properly identified. In many applications, the gamma-rays expected to appear in the spectrum are well known in advance and the corresponding peaks can be identified by inspection. In other applications, unknown gamma-ray spectra may occur and hence a spectra calibration gammaray source is used to supply peaks of known energy in the spectrum. Accurate calibration should involve a standard source with gamma-ray energies that are not widely different from those to be measured in the unknown spectrum. Because even the best spectrometer systems often show nonlinearities of a channel or two over a full range of several thousand channels, it is also useful to have multiple calibration peaks at various points along the measured energy range of interest. The selection of standards to be used for germanium spectrometer calibration depends on the energy range of interest. (b) Detection efficiency In principle, all detectors give rise to an output pulse or signal for a quantum of radiation, which interacts within its active volume. Radiation such as gammaray must first undergo a considerable interaction in the detector crystal before detection is possible. 14 Because gamma photons can travel large distance between interactions, detectors are often less than 100% efficient. It then becomes necessary to have a precise figure for the detector efficiency in order to relate the number of pulses counted to the number of photons incident on the detector (Knoll,1989) , (Gilmore & Hemingway,1995). (c) Intrinsic efficiency εint = no. of pulses at the detector output no. of radiation quanta incident on detector (1-12) The intrinsic efficiency of a detector is a detector property and independent of the geometry, therefore it is much more convenient to tabulate values for intrinsic efficiencies. The intrinsic efficiency of a detector depends on the detector material, the radiation energy, and the physical thickness of the detector in the direction of the incident radiation. (d) Absolute Efficiency (photopeak) εabs = no. of pulses recorded in photopeak no. of radiation quanta emitted by source (1-13) The absolute efficiency is dependant not only on detector properties but also on the details of the counting geometry such as the distance from the source to the detector. By using many calibration sources with known activities, the absolute efficiency of the detector for each gamma-ray line can be calculated from the formula; εabs = N A  P (1-14) 15 Chapter (II) Review of literature 2.1. Review of literature All living organisms are continually exposed to ionizing radiation, which has always existed naturally. The sources of that exposure are cosmic rays that come from outer space and from the surface of the sun, terrestrial radionuclides that occur in the earth’s crust, in building materials, in air, water, foods and in the human body itself. Some of the exposures are fairly constant and uniform for all individuals everywhere, for example, the dose from ingestion of potassium-40 in foods. Other exposures vary widely depending on location. Cosmic rays, for example, are more intense at higher altitudes, and concentrations of uranium and thorium in soils are elevated in localized areas. Exposures can also vary as a result of human activities and practices. In particular, the building materials and design of houses and their ventilation systems strongly influence indoor levels of the radioactive gas radon and its decay products, which contribute significantly to doses through inhalation (Training course series No.40, 2010). So, it is necessary to study the naturally occurring radiation levels in the different components of the environment. This is to obtain the performance of extensive surveys in any country. Such investigations could be useful for both assessment of public dose rates and the performance of epidemiological studies as well as keeping reference-data records to ascertain possible changes in the environmental radioactivity due to nuclear, industrial, and other human activities. (Solomon ,2005). 2.1.1. Survey of natural radioactivity in different components in the environment. 16 2.1.1.1 Radioactivity in lakes. Fahmi et al., (Fahmi et al., 2010) determined the natural radionuclides belonging to 232 238 Th, U decay chains and 40 K. In contents of beach sands and bottom sediments collected at various locations over Idku coast and Idku Lake, respectively. Results showed that for Idku Lake the levels of 238 U were ranged from 11.19 Bq/Kg to 39.33 Bq/Kg with an average of 20.37 Bq/Kg; the levels of 232 Th were ranged from 11.4 Bq/Kg to 43.31 Bq/Kg with an average of 26.05 Bq/Kg and levels of 40K were ranged from 163.05 Bq/Kg to 507.95 Bq/Kg with an average of 329.18 Bq/Kg. El-Reefy et al., (El-Reefy et al., 2009) measured the average radiation values of 226 Ra , 232 Th , and 40 K , in the bottom sediments collected from the east of the Burullus Lake. The values were found to be ranged from 10.3 to 21.8 Bq/kg, 11.9 to 34.4 Bq/kg, and 268 to 401 Bq/kg, respectively. The study showed that 40K concentration was nearly uniform throughout the studied area while 232 226 Ra and Th were more concentrated in the northeastern shore. Agbalagba et al., (Agbalagba et al., 2011) measured the natural radioactivity levels in soil, sediment and water samples in four flood plain lakes of the Niger Delta. The mean activity levels of the natural radionuclides 226 Ra, 232 Th and 40K is 20 ± 3, 20 ± 3 and 180 ± 50 Bq kg−1, respectively. These values are well within values reported elsewhere in the country and in other countries with similar environments. Simon Adu et al., (Simon Adu et al., 2011) determined the concentrations of 238 U, 232 Th, and 40 K in water from Lake Bosumtwi and bore-holes in selected towns around the Bosumtwi basin of the Ashanti region of Ghana. The water 17 samples from the lake were found to contain acceptable levels of radionuclides with mean activity concentrations of 7.9, 89.7 and 0.6 mBq/L for 232 238 U, 40 K, and Th, respectively. The water samples from the bore-holes recorded mean activity concentrations of 7.7, 85.5, and 3.3 mBq/L for 238 U, 40 K and 232 Th, respectively. The annual effective dose calculated for the lake varied from 0.244 to 1.121 µSv with an average of 0.763 µSv and that calculated for the boreholes varied from 0.296 to 2.173 µSv with an average of 1.166 µSv. The radionuclides concentrations in water from the bore-holes and that of the lake, which serve as sources of water supply to the surrounding communities are negligible and pose no radiological hazards to the public. Jovanovic et al., (Jovanovic et al., 2012) the radiochemical analysis of the content natural radionuclides 238 U, 232 Th and 226 (Kyrgyzstan) showed that the concentrations of Ra in soils near Issyk-Kul lake 232 Th are fluctuating in the limits (11.7- 84.1) ×10-4% in the soils. The greatest concentration of thorium-232 has been found in the light chestnut soils. The content of 238 U in the soils near Issyk- Kul Lake is fluctuating from 2.8 up to 12.7×10-4%. The concentrations of 226Ra are fluctuating in the limits (9.4 - 43.0) ×10-11%. The greatest concentration of 226 Ra (43.0±2.8) ×10-11% has been determined in the light chestnut soil. 2.1.1.2 .Radioactivity in rocks: Ahmed et al., (Ahmed et al., 2006) found that the activity concentrations (Bq/Kg) in igneous and metamorphic rock samples from different locations in Egypt and Germany samples for 226 Ra, 232 Th and 40K range from 3.9- 57.4, 3.2- 63.4 and 202- 1211 Bq/Kg in Egypt samples and 5.1-76, 3.4- 70 and 10- 2070, 18 Bq/Kg in Germany respectively. Even though these radionuclides were widely distributed, depending on the local geological conditions. AlZahrani et al., ( AlZahrani et al., 2011) measured the specific activities due to 226 Ra , 232 Th and 40K in phosphorite deposits samples, collected from both surface and sub-surface sections in the Turayf, the Thaniyat Turayf, and the Umm Wual regions of northwestern Saudi Arabia. The average activity of 226 Ra, 232 Th and 40K in phosphate rocks were 513.1 ± 2.5, 39.1 ± 1.5 and 241.7 ± 4.3(Bqkg1 ). The calculated external γ-radiation dose received by the workers of the Phosphorite deposits was 260 μSv/y, which was far below the world allowed dose of 20 mSv/y (ICRP-60, 1990) the International Commission Radiological Protection for workers. Baloguna et al., (Baloguna et al., 2003) determined the natural radioactivity associated with the mining of Nigerian bituminous coal. The activity concentrations of the radionuclides detected range from 0.20 ± 0.002 to 48.42 ± 5.32 Bq kg-1. The overall natural radionuclide contribution to the radioactivity of the environment was found to be 404.16 ± 23.44 Bq kg-1. A comparison of the concentrations obtained for coal with those from other parts of the world indicates that the radioactivity content of the Nigerian bituminous coal was not significantly different. The outdoor and indoor exposure rates in air 1m above the ground were estimated to be (6.31 ± 1.20) ×10-8 and (7.57 ± 1.20) ×10-8 Gy h-1 , respectively, for the mining environment. These values compare very well with the global values reported by UNSCEAR (5×10-8 and 6×10-8 Gy h-1), respectively. The resulting annual effective dose equivalent estimated was (4.49 ± 0.74) ×10-4 Sv yr-1. This also compared favorably with the global value (-4×10-4 Sv yr-1) reported by UNSCEAR. 19 Chiozzi et al., (Chiozzi et al., 2002) used field γ-ray spectrometry for the quantitative assessment of radioactive elements and the expected radon flux of rocks cropping out at the Alps–Apennines transition zone (NW Italy).The lowest238U concentration( 0 - 5 ppm) was found in tectonic units mainly formed by rocks of mafic composition. The average 238U concentration increased to (2.6 – 4.1 ppm) in shales of different units and calc-schists, and it was highest (5 - 6 ppm) in the dolomitic rocks. Shales and phyllitic schists of pelagic origin showed the highest 226 232 Th concentrations. The expected radon exhalation from the decay of Ra within the 238 U decay series was, consequently, lower in the ophiolitic rocks (0.7 – 2.2 Bq m−2 h−1) and higher in calc-schists and dolomites (18.4 – 20.7 Bq m−2 h−1). The estimated radon flux was also significant in shales and phyllites (15.1 – 18.4 Bq m−2 h−1). Walley El-Din et al., (Walley El-Din et al., 2001) measured the absorbed dose rate due to the natural radioactivity in rock samples. It was ranged from 2.45 ± 0.07 to 64.44 ± 1.93 nGy/h for marble and from 41.55 ± 1.25 to 111.94 ± 3.36 nGy/h for granite. The radium equivalent activity varied from 5.46 ± 0.16 to 150.52 ± 4.52 Bq/kg for marble samples and from 229.52 ± 6.89 to 92.16 ± 2.76 Bq/kg for granite. The value of radium exhalation rate varied from 8.0 ± 2.39 to 30.20 ± 5.06 Bq/m2/d for marble and 6.89 ± 1.72 to 25.79 ± 4.38 Bq/m2/d for granite and the effective radium content was found to vary from 1.700 ± 0.51 to 6.42 ± 1.08 Bq/kg for marble and 1.29 ± 0.32 to 5.63 ± 0.96 Bq/kg for granite. The values of the radon exhalation rate and effective radium content are found to correspond with the values of uranium concentration in the corresponding sample. 20 2.1.1.3. Radioactivity in vegetation, drinking water and food Hosseini, (Hosseini, 2007) determined the natural radioactivity concentration in soil, drinking water and certain food items samples of Zahedan city in Iran. Also the absorbed dose was calculated across nearby 5 Sistan blouchestan cities in Iran. Results showed that the concentrations of 40K, 238U and 232 Th in the samples of the city varied from 396 ± 38.4 to 576 ± 57.4 BqKg-1 with a mean of 473.3 ± 40.7 BqKg-1 for 40 K, whereas for 238 U and 232 Th values varied from 20.6 ± 2.3 to 24.7 ± 3.6 BqKg-1 with a mean of 21.9 ± 2.8 BqKg-1 and from 28.9 ± 3.3 to 36.5 ± 3.6BqKg-1 with a mean of 33 ± 3.7 BqKg-1, respectively. The absorbed dose rate in the air across zahedan cities border ranged between 16 ± 5 nGyh-1 and 300 ± 44 nGyh-1 and the gross mean was 158.0 ± 24.5 nGyh-1. It can be concluded that no risk threat the residents around and center Zahedan city and in above mentioned border. Umar et al., ( Umar et al., 2012) natural radioactivity in environmental samples (soil, vegetation and water)from the (Idu) industrial district of federal capital territory (FCT) Abuja, Nigeria was measured to establish a baseline data for activity concentration of 40K , 226Ra and 232Th . The highest activity concentration of 40K, 226Ra and 232Th were found in soil collected from location S2 (943.1Bq/Kg), in vegetation vc (82.3Bq/Kg) and in soil collected from location s3 (107.3Bq/Kg), respectively, where only the activity from s2 is higher than the world average of 420Bq/Kg and the highest activity concentrations of both 226 Ra and 232 Th from vc (82.3Bq/Kg) is above the world average of 50Bq/Kg (UNSCEAR 2000). Results also indicated that the activity concentration due to 40K in the soil samples ranked highest against the lowest value obtained for sediments in the water samples. 21 2.1.1.4. Radioactivity in some building materials and consumer products Medhat etal., (Medhat etal., (2012) measured the levels of naturally occurring radionuclides in compact fluorescent lamps (CFLs) commonly used in Egypt. The activity concentration of radionuclides in the chains and from 40 238 U and 232 Th decay K were determined through gamma-ray spectrometry measurements using high-purity germanium in a low-background configuration. It was found that the activity concentrations ranged from 45 - 198 Bq Kg-1 for from 30 – 191 Bq Kg-1 for 232 238 U, Th and from 419 – 935 Bq Kg-1 for 40K. The results obtained from this study show that CFL samples can pose a little significant radiation hazard. The results may be useful in the assessment of exposure and radiation doses due to the natural radioactivity in CFLs. Abu Khadra and Kamel, (Abu Khadra and Kamel, 2005) reported that all samples of raw ceramic materials and the final product showed considerable natural radioactivity concentrations of 238 U, 232 Th series beside the radioactive isotope 40K. Zirconium silicate (ZrSiO4) sample has the highest concentrations for 238 U and for 232 Th, and it was free from 40K. It was obvious that the radioactivity present in ceramic tiles is mostly from zircon used in glaze, which varies due to different purity and formula recipe. These results lead to suggest paying more attention on zircon related process. In addition, controls should be restricted at the zirconium silicate materials. El-Taher, (El-Taher, 2011) determined the natural radioactivity levels of 35 samples of natural and manufactured building materials used in Qassium area, Saudi Arabia. The activity ranged from 12.7 ± 3.4 to 38.4 ± 4.4 Bq Kg -1 for 226Ra, 13.2 ± 0.7 to 49.2 ± 2.3 Bq kg-1 for 232Th and 64 ± 3 to 340 ± 6.7 Bq Kg-1 for 40K. 22 The activities were compared with available reported data from other countries and with the world average value for soils. All building materials showed Ra eq ranged from 39.64 – 122.71 Bq Kg-1. These values were lower than the limit of 370 Bq Kg-1 adopted by OECD (The Organization for Economic Cooperation and Development). The absorbed dose rate in indoor air was lower than the international recommended values of (55 nGy h-1) for all the samples under study. All the materials examined were acceptable for use as building materials as defined by the OECD criterion. Otoo et al., (Otoo et al., 2011) studied the naturally occurring radioactive materials associate with building materials from twelve towns along coastal part of Central Region of Ghana. The activity concentration of 238 U, 232Th and 40K ranged from 27.90 ± 1.06 to 97.89 ± 6.34 Bq/kg, 15.47 ± 0.97 to70.97 ± 5.83 Bq/kg and 89.34 ± 5.20 to 943.44 ± 34 Bq/kg, respectively. The 238 U recorded the highest value of 97.89 ± 6.34 Bq/kg in granite from Ampenyi whilst pebbles from Winneba recorded the lowest activity concentration. The 232 Th activity concentration level ranged from 15.47 ± 0.97 to 70.97 ± 5.83 Bq/kg with clay soil from Kormantse recording the highest while’s pebbles from Apam had the lowest average activity concentration. The average activity concentration of 40 K ranged from 89.34 ± 5.20 to 943.44 ± 34 Bq/kg, with the highest and lowest activity concentration level occurring in Ampenyi. The radium equivalent activity Ra eq, the external hazard index (Hex) (0.17 to 0.48), Internal hazard index (Hin) (0.25 to 0.72), the absorbed dose rate D in air (36.90 to 131.29 nGy/h) and the annual effective dose (ET) (181.02 to 644.00 µSv/yr). The results obtained were found to be within the allowable limit of 1mSv per year for public exposure control recommended by the International Commission Radiological Protection (ICRP) and Organization for Economic Cooperation and Development (OECD). 23 2.1.5 Radioactivity in soil, sediment, sand and water samples. El-Aydarous, (El-Aydarous, 2007) determined the activity concentration of 226 Ra, 232Th and 40K in soil samples from El Taif, in Saudi Arabia. The soil activity ranges from 13 ± 1.2 to 33 ± 3.4Bq.Kg-1 for 232 226 Ra , 11 ± 1 to 27 ± 4.2Bq.kg-1 for Th and 129 ± 5.7 to 230 ± 11Bq.Kg-1 for 40K with mean values of 23.8 ± 2.4, 18.6 ± 1.7and 162.8 ± 7.6 Bq.Kg-1, respectively. The measured activity concentration of 226Ra, 232Th and 40K in soil was lower than the world average. All the soil samples had radium equivalent activities lower than the limit set in the OECD report (370Bq.Kg-1). The overall mean outdoor terrestrial gamma dose rate was 28.98nGy.h-1 and the corresponding outdoor annual effective dose was 0.04mSv.y-1. El-Kameesy, 226 Ra, 232 (El-Kameesy, 2008) Th, 40K, and 210 the radioactivity concentrations for Pb were measured in 40 soil samples from the northwest Libyan coast in the Tripoli region. It was observed that in samples taken at depth 5-10 cm have an average 7.5 ± 2.5 Bq/kg, 4.5 ± 1.3 Bq/kg, 28.5 ± 6.7 Bq/kg, and 10.3 ± 2.7 Bq/kg, respectively. The corresponding results at depths 50-70 cm are 6.7 ± 1.9 Bq/kg for 40 226 Ra , 4.2 ± 1.1 Bq/kg for K , and 9.2± 3.9 Bq/kg for 210 232 Th , 26.6 ± 5.9 Bq/kg for Pb . The range of the absorbed dose rate obtained for the soil samples was from 2.7 n Gy h−1 to 6.1 n Gy h−1 with an average 4.4 ± 1.3 nGyh−1, while the average effective dose rate was 0.0054 ± 0.0016 m Sv y−1 with the range 0.0033 - 0.0075 m Sv y−1. Yousef et al., (Yousef et al., 2007) the activity concentration of radionuclides in surface soil samples around Kitchener Drain area in the North Nile Delta at the coast of Mediterranean sea ranged from 17.05 to 99.15 for 40K , 1.23 to 32.15 for232Th 1.61 to 50.90 (Bq.Kg-1) for238U . The absorbed dose rate in 24 (nGy/h) due to the natural radioactivity of the samples under study was found to be in the range of 1.73 nGy/h to 47.03 nGy/h. Viruthagiri and Ponnarasi, (Viruthagiri and Ponnarasi, 2011) measured the activities due to the presence of 226 Ra , 232 Th and 40K radio nuclides in all the collected brick samples. The measured values of activity in the samples due to 232 Th vary from 25.35 Bqkg-1 to 62.02 Bqkg-1, 226 Ra activities vary from 9.89 Bqkg-1 to 23.48 Bqkg-1 and variation in 40K activities ranges from 342.48 Bqkg-1 to 405.24 Bqkg-1. Chowdhury et al., (Chowdhury et al., 2005) determined the activity concentrations of naturally occurring radioactive materials in soil samples of an elevated radiation background area of nine southern districts of Bangladesh were determined with an aim of evaluating the environmental radioactivity and the radiation hazard. The activity of 226 Ra in soil ranged from 25 to 55 Bq kg-1with a mean value of 42 ± 7 Bq kg-1, That of 232 Th in soil ranged from 52 to 108 Bq kg-1 with a mean value of 81 ± 14 Bq kg-1, while the activity of 40K in soil ranged from 549 to 1762 Bq kg-1 with a mean value of 833 ± 358 Bq kg-1. The previous background radiation survey by the Bangladesh Atomic Energy Commission showed that the external background radiation level of these region is ~2 times (1.0 mGy y-1)( higher than the world average value (0.5 mGy y-1) reported by UNSCEAR 1988 Report. The mean activity of 226Ra, 232Th and 40K observed in the present work was ~1.6, ~3 and 2 times higher than the world average respectively. Diab et al., (Diab et al., 2008) found that the average activity concentration in the collected soil samples from a cultivated area ranged from 6.0 ± 1.2 to 87.5 ± 4.5 BqKg-1 with an average value of 31.12 ± 2.22 Bq.Kg -1for 25 226 Ra, the 232 Th specific activities ranged from 3.8 ± 1.2 to 14.2 ± 3.3BqKg-1 with an average value of 10.96 ± 1.89 BqKg-1 and the 40K specific activities ranged from 71.8 ± 24 to 543.2 ± 26.5 BqKg-1 with an average value of 264.1 ± 11.94 BqKg -1. The absorbed dose in air was found to be 31nGyh -1 within the range (9.7-57.8) nGyh-1 which is in the order of the world average level (57nGyh -1). The radium equivalent activity (Raeq), the external hazard index (Hex) and the annual dose equivalent were also calculated and found to be within the international level. Santawamaitre et al., (Santawamaitre et al., 2010) investigated the levels of naturally occurring radioactivity in surface soils along the Chao Phraya river .Activity concentrations of 238 U, 232 Th and 40K were found to be 55.3 ± 1.2 to 65.2 ± 1.4, 60.7 ± 1.2 to 69.1 ± 1.3 and 393 ± 13 to 478 ± 16 Bq/kg, respectively. Concerning radiological risk, the absorbed gamma dose rate in air from those soils was calculated to be in the range 81.6 ± 1.9 to 90.4 ± 2.1 nGy/h. The outdoor annual effective dose equivalent was calculated to be 100.1 ± 2.3 to 110.8 ± 2.5 mSv/yr. These results were compared with the world mean values. Sujo et al., (Sujo et al., 2004) measured the concentration of 40K, 238U and 232 Th Bq/kg in soil samples taken from areas surrounding the city of Aldama in Chihuahua using HPGe detector. Results of indoor air short-time sampling revealed relatively high indoor radon levels, ranging from 29 to 422 Bq/m3; the radon concentrations detected exceeded 148 Bq/m3 in 76% of the homes tested. Additionally, liquid scintillation counting showed concentrations of radon in drinking water ranging from 4.3 - 42 kBq/m3. The high activity of 238 U in soil found in some places may be a result of the uranium milling process performed 20 years ago in the area. High radon concentrations indoor and in water may be explained by assuming the presence of uranium-bearing rocks underneath of the 26 city, similar to a felsic dike located near Aldama. The estimated annual effective dose of gamma radiation from the soil and radon inhalation was 3.83 mSv. Harb et al., (Harb et al., 2008) measured the specific activity concentrations of 238U series (226Ra), 232Th series (228Ra, 228Th and 232Th), as well as 40K, expressed in Bq/kg for samples obtained from the El-Sabaea phosphate factory. From obtained results the range of 226 Ra values was from 59.7 ± 6.7 to 638.3 ± 31.0 Bq/kg and ranged from 9.4 ± 1.4 to 38.3 ± 4.0 for 232Th series while it was ranged from 308.9 ± 13.2 to 699.3 ± 29.4 Bq/kg for 40K. The mean activity concentrations values of 238U series (226Ra ), 232Th-series (228Ra , 228Th and 232Th ) and 40K activity concentrations in Bq/kg for soil samples from the Area around El- Sabaea phosphate factory were ranged from 65.5 ± 7.1 to 528.4 ± 25.1, 19.2 ± 3.2 to 40.6 ± 6.3 and 213.1 ± 9.5 to 213.1 ± 9.5 Bq/kg. Alias et al., (Alias et al., 2008) determined the radionuclide activity concentrations for 40K, 226 Ra and 228 The mean activity concentrations of Ra in forest, flat, slope and catchments area. 40 K were 125.9 ± 21.1, 70.7 ± 12.4, 55.5 ± 10.9, 61.5 ± 12.5, 61.9 ± 12.8, and 243.0 ± 27.0 Bqkg -1 for forest, flat 1, flat 2, slope 1, slope 2 and catchment areas respectively. The mean activity concentrations of 226 Ra were 20.9 ± 4.1, 16.6 ± 0.8, 17.9 ± 0.8, 20.1 ± 1.4, 18.8 ± 1.7, and 22.1 ± 1.1 Bqkg-1 for forest, flat 1, flat 2, slope 1, slope 2 and catchments areas respectively. The mean activity concentrations of 228Ra were 33.8 ± 2.9, 22.4 ± 2.5, 26.9 ± 2.6, 27.1 ± 3.5, 24.5 ± 3.1, and 36.6 ± 13.2 Bqkg -1 for forest, flat 1, flat 2, slope 1, slope 2 and catchments areas respectively. The mean radium equivalent Raeq are 78.1, 53.5, 60.3, 63.15, 58.2, and 91.4 Bqkg -1 for forest, flat 1, flat 2, slope 1, slope 2, and catchment areas respectively. The mean air absorbed dose rate is lower than the UNCEAR value i.e. 92 nGy/yr. The mean 27 annual effective dose was also lower than the UNCEAR value i.e. 0.07 mSv. The external radiation hazard index is less than 1, which means that it is safe for human to carry out their activities in the area. Agbalagba et al., (Agbalagba et al., 2012) carried out the analysis of naturally occurring radionuclides (226Ra, 232 Th and 40 K) in soil samples collected from oil and gas field environment of Delta state. The activity concentration of the samples were ranged from 19.2 ± 5.6 Bqkg−1 to 94.2 ± 7.7 Bqkg−1 with mean value of 41.0 ± 5.0 Bqkg−1 for 226 Ra, 17.1 ± 3.0 Bqkg−1 to 47.5 ± 5.3 Bqkg−1 with mean value of 29.7 ± 4 Bqkg−1 for 232Th and 107.0 ± 10.2 Bqkg−1 to 712.4 ± 38.9 Bqkg−1 with a mean value of 412.5 ± 20.0 Bqkg−1 for 40K. The values obtained are in good agreement with the world range and values reported elsewhere in other countries. The study also examined some radiation hazard indices, the mean values obtained were, 98.5 ± 12.3 Bq.kg−1 for Radium equivalent activity (Raeq), 0.8 Bqkg−1 for Representative level index (Iγ), 54.6 nGyh−1 for Absorbed Dose rates (D), 0.07 μSvy−1 for Annual Effective Dose Rates (Eff Dose), 0.3 for External Hazard Index (Hex) and 0.4for Internal Hazard Index (Hin). These calculated hazard indices were well below their permissible limit. Mohsen et al., (Mohsen et al., 2007) analyzed sediment samples from two amang processing plants .The range of mean activity concentrations of 226Ra, 232Th and 40K were between 40.94 – 189.58 Bq kg-1, 104.90 – 516.17 Bq kg-1 and 74.8 – 848.0 Bq/kg-1 respectively. The maximum activity concentrations of and 40 226 Ra, 232 Th K recorded were higher than Malaysia’s average and the world’s natural highest. 28 Akram et al., ( Akram et al., 2006) determined the concentration of natural radionuclides in the bottom sediments of Karachi Harbour/Manora channel area. Samples from Layari River were also analyzed to account for background contribution from terrestrial sources. The activity in sea sediment samples from these area was found to vary from 18.5 ± 4.3 to 29.1 ± 3.8 Bq.Kg-1 for 226 Ra , 11.7 ± 1.2 to 27.7 ± 4.2 Bq.Kg-1 for 228Ra , and 332.2 ± 19.3 to 729.2 ± 36.7 Bq.Kg-1 for 40K . The activity in Layari river ranged from 14.9 ± 2.6 to 29.7 ± 2.9 Bq.Kg-1 for 226 Ra , 8.6 ± 0.9 to 31.6 ± 1.3 Bq.Kg-1 for 228Ra and 197.3 ± 11.6 to 643.7 ± 25.9 Bq.Kg-1 for 40 K . The mean values of radium equivalent activity, absorbed dose rate and annual effective dose were 89 Bq.Kg-1, 44nGy.h-1 and 0.055 mSv.y-1 respectively. The value of effective dose was much less than level of 1.0 mSv.y-1, recommended by ICRP (International commission on radiological protection). Zenzaburo and Tuyoshi, (Zenzaburo and Tuyoshi, 1995) measured the concentration of natural radionuclides in sea sediment samples collected from the coastal sea area at Kashiwazaki -Kariwa nuclear power station. The radioactivity levels of 238U, 232Th and 40K were 10 - 58, 12 - 74 and 320 - 550 Bqkg-1 dry weight respectively. Kabir et al., (Kabir et al., 2008) found that the radioactivity levels of 226Ra , 232 Th and 40K in sediment samples collected from water-bodies of the district of Jessore Bangladesh ranged from 23.10 ± 1.53 to 61.76 ± 2.18, 19.71 ± 5 to 85.36 ± 6.8 and 254.46 ± 43.38 to 986.48 ± 42.86 Bqkg –1 with the average value of 42.90 ± 11.05, 47.85 ± 14.26 and 502.73 ± 146.36 Bqkg -1 respectively. Calculated radium equivalent activity and absorbed rate were found to be 155.85 ± 30.96 and 29 71.71 ± 18.48 Bqkg-1, respectively. The results were compared with those of different countries of the world and Bangladesh. Kessaratikoon et al., (Kessaratikoon et al., 2007) determined the specific activities of 40K, 226 Ra and 232 Th, in 80 sand samples collected along the Chalatat and the Samila beaches in Songkhla province. The beach sand specific activity ranged from 89 – 963 Bqkg-1 for 40K, 0 – 120 Bqkg-1 for 226Ra and 0 – 319 Bqkg-1 for 232 Th with mean values: 248 ± 44, 41 ± 5 and 64 ±7 Bqkg -1 for 40 K, 226 Ra and232Th respectively. All the beach sand samples have mean values of radium equivalent activities lower than the limit set in the Organization for Economic Cooperation and Development (OECD) report. Veiga et al., (Veiga et al., 2006) determined the distribution of natural activities produced by 40 K, 226 Ra and 232 Th, for sand samples collected along the coast of four Brazilian States. For some specific beaches, the values of the γ-ray radiation hazard indices exceeded both of the average worldwide exposure (2.4 mSv y−1) due to natural sources and the limits proposed by Organization for Economic Co-operation and Development for building materials. The average values of the radium equivalent activities were evaluated and found to be 696 Bq kg−1 in Mambucaba (RJ), 1621 Bq kg−1 in Buena (RJ), 2289 Bq kg−1 in Anchieta (ES), 10 205 Bq kg−1 in Meaipe (ES), 83 425 Bq kg−1 in Guarapari (ES), 531 Bq kg−1 in Vitόria (ES), 2026 Bq kg−1 in Serra (ES), 3240 Bq kg−1 in São Mateus (ES), 3075 Bq kg−1 in Porto Seguro (BA) and 1841 Bq kg−1 in Itacaré (BA). These values are above the limit (370 Bq kg−1) recommended for the safe use of building materials for dwelling by OECD. 30 Lawluvi et al., (Lawluvi; et al., 2011) investigated the levels and hazards associated with the 238U, 232Th and 40K in beach sands from some renowned tourist resorts in the Greater Accra region of Ghana. The total absorbed dose rate and the annual effective doses were calculated. The specific activities ranged from 11.0 31.8 Bq kg−1for 238U, 0.5 - 1.5 Bq kg−1for 235U, 10.9 - 103.7 Bq kg−1for 226Ra, 16.8 - 231.2 Bq kg−1for 232 Th and 68.3 - 183.9 Bq kg−1for 40 K. Mean values of the absorbed dose rate, annual external effective dose, radium equivalent activity, external and internal hazard indices and the radiation level index were ; 54.08 nGy/h, 0.066 mSv/y, 101.0 Bq/kg, 0.27, 0.36 and 0.71, respectively. The results showed that the natural radionuclides in samples of the beach sand do not posed any significant risk to tourists and other holiday makers. Sand from the beaches was also safe for use as construction material, indicating the relevance in terms of the radiological quality of the beaches from both human and environmental health view points. RadenkoviĆ et al., (RadenkoviĆ et al., 2009) determined the activity concentrations for the radionuclides 226 Ra, 232 Th and 40 K in the analyzed sand samples. Results of the sand samples randomly taken from both sea and river beach areas of tourist zone, showed low activity concentration of 226Ra and 232Th , originating from the natural radioactive series, as well as naturally occurring The minimum activity concentration 2.24 Bq kg–1 of 226 40 K. Ra was determined in the sand sample from the Copacabana Beach (Brazil), while the maximum value of 15.9 Bq kg–1 was found in the sand from the Great Beach of Ulcinj (Montenegro). The activity concentrations of 232 Th were in the range 2.6 – 17.3, with a minimum value for the Patara Beach (Turkey) and a maximum for the Manhattan Beach (USA). 31 Ismail et al., (Ismail et al., 2009) investigated the levels of natural radioactivity and associated radiation hazard in some Malaysia’s sand used in building constructions. Samples were obtained directly from local hardware stores. The activity concentration of 226 Ra (238U series), 232 Th and 40 K were determined using gamma-ray spectrometry. Activity concentration of 226Ra (238U series), 232Th and 40K were found in the range of 6.45 to 107.90 Bq kg –1, 7.78 to 96.67 Bq kg–1 and 31.05 to 1105.53 Bq kg–1 respectively. The mean range of representative gamma level indexes were found to be in the range of 0.189 ± 0.027 to 2.366 ± 0.057 whereas the mean range of annual equivalent doses to dwellers were in the range of 0.059 ± 0.005 mSv/yr to 0.738 ± 0.018 mSv/yr. Kabir et al., ( Kabir et al., 2010) found that the activity concentration of Ra range from 9.01 ± 1.08 to 96.77 ± 4.30 Bq kg–1 with mean value 31.51 ± 226 17.22 Bq kg-1. The activity concentration of 232Th was found to range from 20.89 ± 1.23 to 59.10 ± 10.47 Bq kg–1with mean value of 34.74 ± 11.63 Bq kg–1 and that of 40 K from 319.29 ± 72.59 to 1227.08 ± 88.74 Bq kg–1 .The mean value being 761.52 ± 262.54 Bq kg–1. It is also observed that the measured activity concentration of 40K exceeded markedly the values of both radium and thorium. Results showed that in all the water-hyacinth samples 40 K represented more than 80% of the natural radioactivity. Karahan et al., (Karahan et al., 2000) activities of eight well and five tap water samples taken in Istanbul were determined. 226 Ra, 222 Rn, 214 Pb, 214 Bi, 40 K, activity concentrations in four lake, four sea water, one snow and one rain water samples were also analyzed in order to determine their radioactivity. The results obtained showed that, in general, natural activities in drinking water samples did not exceed WHO (World Health Organization) and ITS (Institution of Turkish 32 Standards) guidelines. In sea and lake water, four samples were over WHO and ITS guidelines. Concentrations ranging from 0.007 to 0.04 Bq L-1 and from 0.02 to 0.1 Bq L-1 were observed for drinking water. An average annual effective dose equivalent of 0.84 mSv y-1 for 226Ra was calculated. Vesterbaka, (Vesterbaka, 2007) estimated the mean annual effective dose from natural radionuclides. These values were 0.41 mSv for users of drilled wells, 0.05 mSv for users of wells dug in the ground and0.02mSv for people using water from waterworks. The highest effective dose from drinking water was caused by 222 Rn constituting 75% and 60% of the total effective dose caused by all natural radionuclides. 210Po and 210Pb contributed the most of the effective dose caused by long-lived radionuclides. Contribution of the isotopes of radium (226Ra and 228 Ra) to the total effective dose from drinking water was minor. Mohammadi, (Mohammadi, 2010) used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose and also, measured the concentrations of 210 Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226 Ra in Iranian drinking water was below the (100 mBq L-1) recommended by the World Health Organization while the average concentration of 210 Po and 210 Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market. El-Daly and Hussein, (El-Daly and Hussein, 2008) measured the radioactivity levels of 226 Ra (238U) in soil samples collected from north western 33 desert of Egypt. the results obtained indicate that the radioactivity levels of 226 Ra (238U) for soil samples ranged from 14.82 to 26.56 Bq kg–1 with mean average value 22.12 Bqkg–1, while in 232 Th the highest value was 20.99 Bq kg–1 and the lowest value was 3.91 Bq kg–1 with average value10.27 Bq kg–1, while 40 K the activity ranged from 382.98 to 58.02 Bq kg–1 with average value 180.04 Bq kg–1. In case of marine sediment, the concentration of 238 U, 232 Th and variations in activities, which range from 9.80 to 2.34 Bq kg–1 for average value 5.47Bq/kg, 2.13 to 0.6 Bq kg–1 for 232 40 238 K showed U with mean Th with average range 0.92 Bqkg-1, as well as, 40K which vary with range from 4.5 to 25 Bq kg –1 with mean average value 11.43 Bqkg-1. El-Tahawy et al., (El-Tahawy et al., 1994) measured the activity concentration of 238 U, 232 Th and 40K in sediment and water samples from Suez Canal. The average activity concentrations of 238 U, 232 Th and 40K in sediment samples were 10.69  0.25, 13.71  0.28 and 194.58  0.81 Bqkg-1 dry weight respectively. The average activity concentration of 40K in water samples was 15.92  0.41 BqL-1. Ashnani et al., (Ashnani et al., 2010) measured the average activity concentration of 226 Ra, 40 K and 232 Th in water, soil and sediment samples from Aras River and south west of Caspian Sea. In water, soil and sediment samples the average activity concentrations of 40 K and 226 Ra were 263.75±6.18 BqKg-1 and 4.42±0.46 BqKg-1 respectively and in soil and sediment samples the average concentrations of activity of 232 Th was 20.24±1.18BqKg-1. results showed that in one third samples the activity of 40 K is more than allowable limitations and other natural activities are in range of background. 34 Ramasamy et al., (Ramasamy et al., 2009) determined the activity concentration of natural radionuclides (238U, 232 Th and 40 K) for all samples. It varies from site to site, because river bottoms can exhibit large variation in chemical and mineralogical properties. The mean activity concentration ranges for 238 U, 232 Th and 40 K are below detectable limit (BDL) - 11.60±6.13Bq/kg with an average 7.31 ± 3.41Bq/kg, BDL - 106.11 ± 9.20Bq/kg with an average 46.85 ± 5.25Bq/kg and 201.23 ± 19.90 - 467.71 ± 34.34Bq/kg with an average 384.03±26.82Bq/kg respectively. 35 Chapter (III) Materials and methods 3. 1.Materials 3.1.1. Chemicals and reagents Unless otherwise stated, all acids, bases and salts were of the analytical grade obtained from BDH Company, England .Double distilled water was used in the preparation of the different solutions used. 3.1.2. Radioactive isotopes All the radioactive isotopes were from IAEA / RL / 148, Vienna, 1987 1-Uranium-238 (R G U.1): 4.9298 Bq/ gm 2- Thorium-232 (R G Th.1): 3.247 Bq/gm 3- Potassium-40 (R G.K.1): 30 Bq/gm Table 3.1: shows their components concentrations and the confidence interval Table 3.1 Radioactive Component Conc. isotope U 400 μg/g Uranium-238 Thorium-232 Potassium -40 Confidence interval ±2μg/g Th < 1μg/g ― K < 20μg/g ― Th 800μg/g ±16μg/g U 6.3μg/g ±0.4μg/g K 0.02% ±0.01% K 44.8 % ±0.390 U < 0.001μg/g Th < 0.01μg/g 36 3.2 Sample collection 3.2.1 Site location: Lake Qarun is the only enclosed saline lake in Egypt. It is located in the western desert part of Fayoum depression and lies 83 km southwest of Cairo. The lake is located between longitudes of 30° 24` & 30° 49` E and latitude of 29° 24` & 29° 33` N. It is bordered from its northern side by the desert and by cultivated Land from its south and southeastern side. The lake receives the agricultural drainage water from the surrounding cultivated land. The drainage water reaches the lake by two huge drains, El-Batts drain (at the northeast corner) and El-Wadi drain (near mid-point of the southern shore) (Abou El-Gheit et al., 2012). Fig. 3.1: Location of Qarun Lake in El-Fayoum depression. 3.2 Sample collection 20bottom sediment samples, 35 water samples and 20shore sediment samples were collected from Qarun Lake in the east area from El-Bats drain(I) to El- Wady drain (Shakshok area)(III). 20 soil samples collected from the agriculture land in the south area around the lake. Fig 3.2 shows the sampling locations on the map of Qarun Lake and Table 3.2 shows the code number of the collected samples. 37 Fig 3.2: Map of Lake Qarun showing sampling locations. Table 3.2: Code number of the collected samples. Code No. W1 Location Represent the water sample at the starting point (I). W35 The last sample of water at the end point (III). S1 Represent the first bottom sediment sample at point (I). S20 The last bottom sediment sample at point (III). H1 Represent the first shore sediment sample at point (I) on the shore of the lake. H20 The last shore sediment sample at point (III) on the shore of the lake. F1 The first soil sample from cultivated land. F20 The last soil sample. 38 3.3. Instruments: The following instruments were used in our study: 1-High-resolution gamma -spectroscopic system: Gamma-ray spectrometer contains n-type HPGe coaxial detector of 17% efficiency having an energy resolution of 1.73KeV at 1332 KeV of 60Co gamma – ray line and coupled with - Multi channel analyzer (MCA) of 4096 channels to determine gamma energies. The detector was surrounded with a lead shielding material to reduce the background radiation entering it. The detector is mounted in a 30 liters liquid nitrogen Dewar for the germanium crystal temperature control. The preamplifier is coupled to the detector and connected to the germanium crystal, so that its input components are kept at the liquid nitrogen temperature. Computer was used for data processing and evaluation using a pulse height analysis system which includes a software package, peak calculation system also for energy calibration and energy related efficiency calibration and radionuclides identification as half-lives, photon energies and emission probabilities. 3.3.2.-X-ray diffractometer: X-ray diffraction is one of the most useful techniques used in clay mineral identification (Brindly and Brown, 1980). The basic phenomenon of diffraction analysis is the reflection of x-ray by the atomic plane in crystals through an angle (A) which is quantitatively related to the distance of separation of the atomic planes (dAº). This is governed by Braggꞌs law as follows: Nλ = 2d sinθ (3-1) Where: n= order of the diffracting radiation. λ= wave length of the incident x-ray. d= distance between similar planes of atoms in the substance. 39 θ= angle of diffraction. Soil samples under investigation were prepared by drying and grinding to a very fine powder. For each sample three portions were prepared: the first one was untreated, while the second was treated with ethylene glycol, and the third was heated at 500ºC for one hour. X-ray diffraction analysis was performed on these three samples to identify their minerals content. From the x-ray diffraction pattern, the values of (d) as a function of (I/Iο) was tabulated for all of the used samples, then the experimental data were compared with standard tabulated data presented in the American Society for Testing and Materials (ASTM) files, to identify the present minerals and their chemical composition. 3- Thermogravimetric analysis (TGA): When matter is heated, it undergoes certain physical and chemical changes. Physical changes include phase changes such as melting, vaporization, crystallization, transitions between crystal structures, changes in microstructure in metal alloys and polymers, volume changes (expansion and concentration) and changes in mechanical behaviour. Analysis was performed using a Netzch STA409EP apparatus. Thermal analyses were carried out in the range 20-800° C, with a heating rate of 10 Kmin-1. Powdered samples (24mg) were analyzed in alumina crucible. Thermogravimetric analysis (TGA) measures the mass (weight) of a sample in a specified atmosphere as the temperature of the sample is programmed. The most common temperature program is a linear increase in temperature with time, although isothermal programs, stepped temperature programs, and so on can be used. In the most common TGA experiment, the sample temperature is increased linearly over a time period and the mass of the sample is constantly recorded. The output from a TGA experiment is a plot of mass (or mass %) vs. Temperature (Elving and winfordner (1974). 40 4-Fourier transforms infrared spectroscopy (FT-IR) Infrared radiation interacts with chemical bonds to cause stretches, bends and various other atomic vibrations. For a vibration to give rise to absorption of infrared radiation, it must cause a change in the dipole moment of the molecule. The larger this change the more intense the absorption band will be. Infrared spectroscopy reveals information about molecular vibrations that cause a change in the dipole moment of molecules. It offers a finger print of the chemical bonds present in the molecules. FTIR is a very powerful analytical tool for examining both organic and inorganic materials. FTIR spectrometry uses the technique of Michelson interferometer. As a beam of radiation from the source is focused on a beam splitter. A half of the beam is reflected to a fixed mirror and the other half of the beam is transmitted to a moving mirror, which reflects the beam back to the beam splitter. From there it travels recombined with the original half beam to the detector. All IR spectra were recorded using a Jasco FT/IR-460 pulse, Japan. Samples were recorded as a KBr disc (1:10, sample/KBr), using 16 scans per sample at a resolution of 4 cm-1 over the range 4000-400cm-1 (Breky, 2012). 5-X-ray Fluorescence Technique Wavelength dispersive x-ray florescence spectrometry is a non-destructive analytical technique used to identify and determine the concentrations of elements presents in solid, powder and liquid samples. When sample atoms irradiated with high energy primary x-ray photons, electrons are ejected in the form of photoelectrons. This creates electron holes in one or more orbital, converting the atoms into ions, which are unstable. To restore the atoms to stable state the holes in inner orbital are filled by electron from outer shells. Such transition may be accompanied by energy emission in the form of a secondary x-ray photon, this phenomena known as fluorescence. In the present work the elemental analysis of the sample was carried out using Philips Pw-2400 Sequential X-ray spectrometer. The test samples were grind to as fine as a particle size as possible in our laboratory. The resulting powder being pressed into pellet of about 40mm diameter and a thickness in excess of the maximum analysis depth (thickness of 5mm are typical) (Hilal, 2002). 41 6-PH Meter: The pH measurements were carried out using Hanna pH meter model 8417 with combined reference and calomel electrodes. The apparatus was calibrated before use with standard buffer solutions of pH 4.01 and 7.01 . 3.4. Experimental procedures and methods of calculation: This section gives a brief description of the methods and procedures of the experimental work. Equations required for the calibration of the data are also briefly discussed. The experimental work includes three parts: 3.4.1. Physical characteristics, mineralogical characteristics and thermal analysis of the chosen soils samples were determined according to standard methods (Buzas, 1993) 3.4.2 Gamma spectrometric measurements of environmental samples: In this part, the radiation levels of different raw environmental samples (sediment, water and shore) from different locations from Qarun Lake, and soil samples collected from agriculture land around the lake were measured using a high resolution gamma spectroscopic system. Natural Uranium and Thorium radioactive series, as well as K-40 levels have been determined. These radio nuclides contribute to the background exposure. 3.4.2.1. Sample preparation: The collected water samples were left overnight in polyethylene container to allow settling of any suspended solid materials and a clear supernatant was separated by decantation. The clear water was acidified using concentrated mineral acids, to prevent any loss of radium-isotope around the container walls, and to avoid growth of micro-organisms (Akram, et al., (2006). Sediment and soil samples were dried in an oven at 100° to remove the moisture content until a constant weight was obtained. The dried sediments were pulverized and sieved to pass through a coarse mesh (1-2 mm size fraction). The meshed sediments were transferred to plastic jar containers of specific geometry similar to that of the 42 calibration source for gamma activity analysis. The net weight of each sample was calculated. The samples were sealed tightly to limit the possible escape of radon (Kabir, et al., (2010) and left for at least 4 weeks (> 7half-lives of 222Rn and 224Ra) before counting by gamma spectroscopy in order to ensure that the daughter products of 226Ra up to 210Pb and of 228Th up to 208Pb achieve secular equilibrium with their respective parent radionuclides (Kessaratikoon, et al., (2007). 3.4.2.2. Detector calibration: The object of energy calibration is to derive a relationship between peak position in the spectrum and the corresponding gamma-ray energy. This is normally performed before measurement, Energy calibration is accomplished by measuring the spectrum of a source emitting gamma-rays of precisely known energy and comparing the measured peak position with energy. In practice, it is sufficient to measure the spectrum long enough to achieve good statistical precision for the peaks to be used for the calibration. The calibration process then involves providing a list of calibration peaks to be used and their true energy (Kessaratikoon, et al., (2007). The gamma ray spectrometer system was calibrated by applying different gamma emitters such as: cesium-137 (661.66KeV), cobalt-60 (1173.23 KeV, 1332.5 KeV), Na-22(1274.53KeV) and Ba-133(356.017KeV). Fig 3.5: Energy calibration curve. 43 It is necessary to determine the photo peak efficiency as a function of energy and measurement geometry by using standard reference sources. The system calibration was performed by using three well-known reference materials obtained from the International Atomic Energy Agency for K, U and Th activity measurements: RGK-1, RGU-1 and RGTh-1(Table.1).The standard sources used in this study were U-238 , Th-232 and K-40 in a powder form. These sources were counted in a plastic jar as that used with the environmental samples under investigation. The efficiency (Eff) for this special geometry is calculated by: Eff = Z AI (cps/Bq) (3) Where: Eff = photopeak efficiency (count.sec-1/Bq), Z = (net count / sec) for the standard, A = activity of the radionuclides (Bq), I = intensity of the gamma line. This efficiency calculation was made for each gamma-ray energy line. Fig (3.6) shows relation between photo peak efficiency and the gamma ray energy (KeV). 44 Fig 3.6. Gamma spectrometry efficiency calibration curve. 3.4.2.3. Counting procedures Measurements were carried out on the studied samples using γ-ray spectrometer contains n-type HPGe coaxial detector. Coupled with 4096 multichannel analyzer (MCA). Radioactivity concentration of each sample was measured for about 24 hours. The background activity was measured by counting the same type of the plastic jar containing bidistilled water for solutions samples. For soil samples, the pure silica was used instead of bidistilled water in the same plastic jar, and counted for the same time as that of the sample. Since the detection system gives only the count rate that is proportional to the amount of radioactivity in the samples, the radioactivity concentration in the environmental samples was obtained as follow (Santawamaitre, 2000): A= Cn E  P  t  m (Bq/Kg). (4) Where: A: is the activity concentration of a particular nuclide in Bq/kg. Cn: is the net count (background subtracted) in the corresponding photo peak. Εγ: is the absolute efficiency at photo peak energy. Pγ: is the gamma-ray emission probability corresponding to the photo- peak energy. t: is the counting time in second and m: is the mass of soil sample in kg . Direct determination of 226Ra and 232Th in sediment without any chemical treatment using semiconductor γ-ray spectrometer is very hard because they do not emit any intensive γ- rays (lines) of their own, but they have several progenies which have more intensive lines and activities equal to their parents in the state of 45 secular equilibrium. As a result, the measurements of the radionuclides relied on the detecting emissions from their progenies (Akram, et al., 2006). The activity concentration of 232Th, 238U and 40K determined using gamma spectroscopy technique for water, sediment and shore samples collected from Qarun Lake and also for soil samples collected from cultivated agriculture land around Qarun Lake. The activity concentrations of the samples under investigation in Bq/Kg were determined from the photopeaks of the gamma spectra corresponding to 232Th, 238U and 40K. Estimation of the count rates for each detected photo-peak and radiological concentrations of detected radionuclides depend on the establishment of secular equilibrium in the samples. Since secular equilibrium was reached between 232Th and 238U and their decay products, the 232 Th concentration was determined from the average concentrations of (208Tl, 212 Pb, 228Ac) in the samples, and that of 238U (226Ra) was determined from the average concentrations of 214Pb and 214Bi decay products. Thus, an accurate radionuclide concentration of 232Th and 238U was determined, whereas a true measurement of 40 K (1460) concentrations was computed (Harb, et al, 2008). 3.4.2.4. Low level background gamma-ray spectrometers: The special problem in low-level radioactivity counting is that the ratios of counting rates of sample activity to background are often so low that significant modifications to these spectrometers are needed to improve sensitivity. A goal that is achieved by most gamma spectroscopists is to lower the minimum detectable activity (MDA) of their low level spectrometers, i.e. to obtain more statistical evidence in less time. Simple statistical principles show that MDA is inversely proportional to the detection efficiency and only proportional to the square root of the number of background counts under the peak of interest. The Minimum Detectable Activity (MDA) for each radionuclide 238U, 232Th and 40K was calculated using the following equation: MDA= 1.645 N B f E   E   t c  M (6) 46 Where, 1.645 is the statistical coverage factor at 95% confidence level, N B is the background counts at the region of interest, tC is the counting time, fE is the gamma emission probability, η (E) is the photo peak efficiency and M is the mass of sample. The MDA for each of the radionuclides were calculated as 1.46×10 -7 Bq/kg for 238U, 7.87×10-7 Bq/kg for 232Th and 3.79×10-6 Bq/kg for 40K respectively (Lawluvi, et al ,(2011). 3.4.2.5. Counting statistics: The total uncertainty (tot) of the calculated activity values is composed of the counting statistical (st) and weighted systematic errors (sys,i) calculated by the Following formula: tot = ( st )2 1 / 3i ( sys,i )2 (7) The systematic uncertainties considered include: the uncertainty of the source activity, the uncertainty in the efficiency fitting function, and uncertainties in the Nuclide master library used (EG&G ORTEC, 1999). 3.4.3. Dose assessment (Radium equivalent activity and other radiological hazards for soil samples). Radium Equivalent Activity (Ra eq): For the purpose of comparing the radiological effect or activity of materials that contain 226Ra, 232Th and 40K by a single quantity, which takes into account the radiation hazards associated with them, a common index termed the radium equivalent activity (Raeq) is used. This activity index provides a useful guideline in regulating the safety standards on radiation protection for the general public residing in the area under investigation. The Raeq index represents a weighted sum of activities of the above mentioned natural radionuclides and is based on the estimation that 1 Bqkg -1 of 226Ra, 0.7 Bqkg –1 of 232Th, and 13Bqkg –1 of 40K 47 produce the same gamma radiation dose rates (Al zahrani, 2011). The index is given as: Raeq = CRa + 1.43CTh + 0.077Ck, Where CRa, CTh and Ck are the average activity concentration in Bqkg –1 of 226 Ra, 232Th, and 40K, respectively. Estimation of dose rate (D): Conversion factors to transform specific activities AK, ARa and ATh of K, Ra and Th, respectively, in absorbed dose rate at 1m above the ground (in nGy h -1 by Bq kg-1) are calculated by Monte Carlo method and the values are (UNSCEAR, 2000) D (nGy h-1) = 0.0417A k + 0.462ARa + 0.604A Th In natural environmental radioactivity situations, the effective dose is calculated from the absorbed dose by applying the factor 0.7 Sv/Gy (UNSCEAR, 1993). Effective dose rate: To estimate the annual effective dose rates, the conversion coefficient from absorbed dose in air to effective dose (0.7 Sv Gy-1) and outdoor occupancy factor (0.2).The effective dose rate in units of μSv yr -1 was calculated by the following formula: Effective dose rate (μSv yr-1) =dose rate (nGyh-1) x 8760 h x 0.2 x 0.7 Sv Gy-1 x 10-3) The external hazard index (Hex) can be defined as: Hex = ARa/370 + ATh/259+ AK/4810 ≤ 1, Where: ARa, ATh and AK are the specific activities of 226Ra, 232Th and 40K in Bqkg−1, respectively. This index value must be less than unity in order to keep the radiation hazard insignificant (Alias, 2008). 48 3.5 Safety precautions: The laboratory safety precautions were completely considered during the use of radioactive materials. Dosimeters and films badges were used all time. 49 Chapter (IV) Results and Discussion 4. Results and discussion 4.1. Characterization of the studied samples. Determination of solid samples constituents and structure has a vital role in natural radioactivity assessments generally. The aim of this study was to investigate the potential of the thermogravimetric analysis, infrared spectroscopy and XRD techniques for non-destructive measurement of the studied sample properties. 4.1.1. Determination of the thermal stability of (shore, sediment and soil) samples using TGA technique Methods for the determination of soil carbon have in particular gained greater currency in recent times. Loss-on-ignition is still a widely used method being suitably, simple and available. Thermogravimetric analysis (TGA) instrumentation was used to measure carbonaceous components because of its potential to separate carbon and other components using heating programs. Soil thermogravimetric studies has indicated that loss-on-ignition methods are best constrained to temperatures from 200 to 430 °C for reliable determination for soil organic carbon especially where clay content is higher. In the absence of carbon, specific detection where mass only changes are relied upon, exceeding this temperature incurs increasing contributions from inorganic sources adding to mass losses with diminishing contributions related to organic matter. The smaller amounts of probably TG% may represent mineral associated material as SiO2 for shore sediment and bottom sediment samples (Pallasser,et al., 2013). Figure (4.1) and Table (4.1) showed the thermogravimetric analysis of the studied solid samples. The first most important process during the thermal analysis of shore sediment ,bottom sediment and soil samples is weight loss of moisture 50 around 100°C and represented by a slight weight loss percent range from (1.32, 1.1 and 3) respectively and data is cleared at Table (4.1). From 400 – 500o C a remarkable weight loss percent was observed for the soil sample due to the organic degradation (Kniker et al, 2008) of the local granitic rocks and phosphate fertilizers used in the cultivated soil samples (Miyazawa et al, 2000). The total weight loss percent up to 800°C is (3, 4 and 9) for the studied samples respectively. Table (4.1): Weight loss percent of shore, sediment and soil samples at different heating intervals Sample Wt loss % Room temp.120 oC 200-300 oC 400-500 oC Total weight loss up to 800 oC Shore Sediment 1.32 1.15 0.21 3 Bottom Sediment 1.1 1.5 0.2 4 Soil 3 1 4 9 Fig. (4.1) TGA of shore sediment, bottom sediment and soil samples. 51 4.1.2. X-Ray Diffraction Spectra (XRD) of (shore sediment, bottom sediment and soil) samples. The X-ray diffraction (XRD) analysis was undertaken to investigate qualitatively the composition of mineralogy in the studied samples. It is important to identify clay minerals, for example kaolinite, illite, montmorillonite, chlorite etc. as they may influence the behaviors and properties of the studied samples. The peak in the low angle portion is that at 7.1 Å, attributable to kaolinite (Mubarak, 2012). It is most interesting to note that the intensity of prescribed peaks is comparatively more intense in the soil samples than the bottom sediment samples and disappear in case of shore sediment samples. The reason for this difference is based on clay content difference. It is interesting to note that the two patterns do not show the characteristic 10 Å peak of discrete illite. Quartz is appear in all studied samples as indicated by the intense peak at 3.33 Å(Shrivastava., 2009) and the rest of the series at 4.27, 2.46, 2.28, and 2.12 Å. It is interesting to point out again that the relative intensity of these peaks is higher in case of shore samples than the other samples. Several characteristic peaks of the feldspars series are noticeable in the 3.2 Å regions of all studied samples (Islam & Lotse, 1986). Peak intensity is much higher in case of shore samples. The peak at 3.03 Å in all studied samples is due to calcite. Peak intensity is higher in shore sediment samples than other samples. 52 a-Shore b-Sediment c-Soil Fig. (4.2) XRD of shore sediment, bottom sediment and soil samples. 53 4.1.3. X-ray fluorescence (XRF) of (shore sediment, bottom sediment and soil) samples. X-ray Fluorescence is a technique for chemical compositional measurement in which X-rays of a known energy are directed towards a target or sample, causing the atoms within the material to emit "fluorescent" X-rays at energies characteristic of its elemental composition. The elemental analysis by X-ray fluorescence (XRF) has been performed to determine the main elements present in the studied samples (Baranowski et al., 2002). Table .4.2.shows the ion concentrations percent of shore sediment, bottom sediment and soil .The obtained analysis data indicated that, the main elements present in all shore sediment, bottom sediment and soil samples are Si, group AII elements (Mg &Ca), Al, Fe and Na. In case of shore sample the major element is Si+2, Al+3, Mg+2, Na+, Fe+2 and Ca+2 these elements represent about 87.5%. Generally, the concentration of Al and Si were higher than the other metals in both soil and bottom sediment samples. This may be attributed to the origin of these elements where these elements mainly originating from the land and rock erosion. 54 Table (4.2): Ion concentrations percent of shore sediment, bottom sediment and soil samples using X-ray florescence technique (XRF) Conc. % Ion Shore Sediment sample Bottom Sediment sample Soil sample Si 16.20 58.39 53.02 Al 03.81 11.62 17.28 Ca 63.05 10.49 06.21 Fe 00.89 02.20 07.66 Na 01.92 02.41 00.67 Mg 01.01 02.18 02.14 LOI 12.71 13.12 13.02 LOI= Loss on Ignition. 4.1.4. Infrared (IR) spectroscopy of (shore sediment, bottom sediment and soil) samples IR spectroscopy is one of the most widely used and most important analytical methods in science in general. In geosciences it is a sensitive tool for mineral identification, since every mineral has a characteristic spectrum (Bish & Johnston., 1993). Further applications are:    Mineral identification. Qualitative and quantitative determination of structural incorporated molecules and defects in minerals, e.g. SiO4, SiO6, PO4---, CO3--, OH-, H2O, …. Information about atoms and their bonds. The spectral region of infrared radiation is divided into three parts: Near-IR (NIR): 12500 - 4000 cm-1. Mid-IR (IR-MIR): 4000- 400 cm-1 --- H2O bending and stretching vibrations. 55 Far-IR (FIR): 400 - 0 cm-1 --- MO4, MO6, lattice vibrations. The absorption band in an infrared spectrum (IR) will tell the chemistry of individual information on the identity of the mineral containing the bonds. Thus, IR is complementary to XRD analysis, each resulting in data ancillary to the other. IR is even more important for the study of adsorbed molecules on soil particles (Swann & Patwardhan., 2011). (Fig. 4.3) showed that the strong absorbance in the 3600 to 3800 cm−1 region may be due to hydroxyl stretching vibrations associated with clay minerals from absorbed or molecular water (Al Othman etal., 2011). While the peaks <1800 such as 1081.87, 1039.44 and 785.85 cm-1 occurs due to several silica modes (Saikia & Parthasarathy, 2010). The sharp band at 1500 to 1000 cm−1 may be due to O–Si–O stretching in shore sediment samples and bottom sediment samples due to the free silicon group. The double bonds (e.g., C=O, C=C, and C=N) from 1800 to 1500 cm−1 in soil samples may referred to silicon compound having a carbonyl group attached to the silicon ( Sayed & Khattab, 2010) . 56 Shore Sediment sample Bottom Sediment sample Soil sample Fig. (4.3): The IR spectrum of shore sediment, bottom sediment and soil samples. 57 4.2. Chemical and physical parameters in Qarun Lake samples 4.2.1. pH measurements The meter is designed to measure changes of millivolts between the reference and pH electrodes. The instrument always gives a pH reading directly to measure the free H+ in solution. 4.2.2. Electrical Conductivity Electrical Conductivity (EC) of a solution is a measure of the ability of the solution to conduct electricity. The EC is measured in millisiemence per meter. When ions (salts) are present, the EC of the solution increases. If no salts are present, then the EC is low indicating that the solution does not conduct electricity well. The EC indicates the presence or absence of salts, but does not indicate which salts might be present. For example, the EC of a soil sample might be considered relatively high. No indication from the EC test is available to determine if this condition was from irrigation with salty water or if the field had been recently fertilized and the elevated EC is from the soluble fertilizer salts. To determine the source of the salts in a sample, further chemical tests must be performed (Corwin and Lesch, 2005). The pH and electrical conductivity (EC) (mS /m ) were measured for water, bottom sediment and soil samples. The pH values were on the alkaline side. The pH of Qarun lake water seems to vary in a very small range in the studied samples. The pH values for soil samples around 7 and it is less than bottom sediment due to the existence of acidic fertilizers in soil and also these value prove the existence of carbonate in soil that cleared in IR analysis (Rhoades etal.,1999). The electrical conductivity values for the soil samples is higher than the other studied samples may be due to the presence of expected movable salts. 58 Table (4.3) pH and electrical conductivity for some of the studied samples. Sample name S1 S9 S18 F1 F7 F14 W4 W15 W27 pH 8.35 8.22 8.4 7.5 7.8 7.9 8.1 8.6 8.45 log of Conductivity( mS/m) -92.5 -88.5 -94 -57 -62 -67.5 -98 -103 -101 Where: S1: bottom sediment sample No.1. F1: soil sample No.1. W4: water sample No.4. 4.2.3. Bulk density and total porosity The bulk density and total porosity is also measured for soil and bottom sediment samples. For soil samples the average value of bulk density is 1.4 gm/cm3 and the average value of total porosity is 0.47. These values lie within those reported for other Egyptian soil samples (Avnimelech etal., 2001). In case of bottom sediment samples the average value of bulk density is1.5 and the average value of total porosity are 0.43. 4.3. Natural radioactivity in Qarun Lake samples The study of the background radiation and distribution of natural occurring radioactive materials in the environment has been undertaken to establish a baseline data on the radiation profile of the lakes ecosystem in Egypt. The activity concentrations of the samples under investigation in Bq/Kg were determined from the photopeaks of the gamma spectra corresponding to 59 232 Th, 238 U and 40K. Since secular equilibrium was reached between 232 Th and 238 U and their decay products, the 232Th concentration was determined from the average concentrations of ( 208Tl, 212 Pb, 228 Ac) in the samples, and that of 238 U (226Ra) was determined from the average concentrations of (214Pb and 214Bi) decay products in addition to the single peak of 40K (Mireles etal.,2003). Fig 4.4 shows an example of gamma ray spectrum of a bottom sediment sample together with a background spectrum. Fig 4.4 Gamma ray spectrum for both background (b) and bottom sediment sample (a) Radioactive concentration in different environmental samples (water, bottom sediment and shore sediment samples at different sampling sites (from Qarun Lake) and soil samples collected from agriculture land around Qarun Lake are seen in tables (4.4, 4.5, 4.6 and4.7) respectively where natural uranium and thorium radioactive series, as well as K-40 concentration levels have been determined. The distribution of radioactive concentrations of 238 U, 232 Th and 40K in (water, bottom sediment, shore sediment and soil) samples are shown in Figs (4.5, 4.6, 4.7and 4.8) respectively. 60 Table (4.4) the activity concentrations for 232Th, 238U and 40K (Bq/ L) in the water samples under study Sample No. Activity Concentrations(Bq/L) 232 W1 W2 W3 W4 W5 W6 W7 W8 W9 W10 W11 W12 W13 W14 W15 W16 W17 W18 W19 W20 W21 W22 W23 W24 W25 W26 W27 W28 W29 W30 W31 W32 W33 mean±SD Min Max 238 Th 3.35 ± 0.33 0.97+0.03 BDL 2.05 ± 0.08 3.53 ± 0.21 2.07 ± 0.04 3.11 ± 0.09 3.45 ± 0.17 2.91 ± 0.12 3.14 ± 0.06 1.83 ± 0.05 2.67 ± 0.1 2.04+0.06 2.54 ± 0.1 2.18 ± 0.07 0.98 ± 0.01 0.18±0.03 BDL 1.3 ± 0.02 1.38 ± 0.08 2.04 ± 0.03 1.86 ± 0.05 2.92 ± 0.18 3.14 ± 0.13 2.26 ± 0.08 BDL 0.88 ± 0.02 2.49±0.02 1.59±0.01 2.47±1.03 5.32±1.5 0.56±0.36 3.13±1.04 2.28±1.07 0.18 5.32 U 6.57 ± 0.26 2.48+0.12 BDL 2.17 ± 0.07 3.36 ± 0.2 2.31 ± 0.09 2.32 ± 0.11 4.96 ± 0.12 4.47 ± 0.27 4.97 ± 0.19 2.68 ± 0.17 2.85 ± 0.19 2.337+0.14 2.40 ± 0.08 1.81 ± 0.03 2.32 ± 0.09 0.95±0.01 BDL 2.24 ± 0.07 2.66 ± 0.08 3.37 ± 0.13 1.78 ± 0.05 4.47 ± 0.22 3.77 ± 0.23 2.97 ± 0.06 BDL 2.25 ± 0.07 1.47±0.06 0.59±0.03 4.54±2.1 3.01±1.01 1.07±0.02 2.48±0.52 2.88±1.31 0.59 6.57 61 40 K 43.74±2.74 26±1.3 BDL 23.92±1.47 28.19±1.97 13.07±0.58 20.19±1.61 35.64±2.04 14.58±0.73 43.19±2.3 13.88±0.69 12.09±0.78 20.96±1.25 1.03±0.04 1.34±0.08 4.51±0.32 13.38±0.87 BDL 19.37±1.1 1.08±0.05 27.52±1.7 9.39±0.6 12.50±0.5 17.66±1.44 24.09±1.6 BDL 2.76±0.15 27.88±3.04 43.7±5.07 20.54±3.06 35.02±4.15 7.08±2.04 10.31±2.61 19.57±12.06 4.25 43.74 (BDL) below detectable limit Table (4.5) the activity concentrations for 232Th, 238U and 40K (Bq/ kg) in the bottom sediment samples under study. Sample No. Activity concentrations (Bq/kg) 232 238 Th S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 mean±SD Min Max 14.8 ± 0.46 17.63+0.71 20.04 ± 0.6 18.11 ± 0.92 20.35 ± 1.01 20.24 ± 0.81 18.82 ± 0.56 19.12 ± 0.76 16.12 ± 0.43 17.93 ± 0.89 11.04±0.42 5.9 ± 0.1 7.44 ± 0.27 5.74 ± 0.14 5.99 ± 0.17 7.64 ± 0.45 13.97±0.69 6.68±0.47 14.04±1.12 17.06±1.02 13.93±0.55 5.74 20.35 U 20.6 ± 0.72 24.04+1.2 29.23 ± 1.17 26.29 ± 1.31 29.89 ±1.19 30.15 ± 1.8 28.03 ± 1.74 29.98 ± 1.38 23.82 ± 0.62 26.30 ± 1.47 17.05±0.65 10.19 ± 0.27 10.45 ± 0.47 7.06 ± 0.28 11.35 ± 0.74 11.49 ± 0.69 21.51±1.29 6.52±0.87 10.24±0.61 13.2±0.66 19.37±1.16 6.52 19.37 62 40 K 284.88±8.54 332.47±11.3 335.28±11.49 351.88±14.21 344.61±11.6 343.76±11.43 351.68±14.82 327.96±10.23 265.21±9.34 324.99±10.22 281.02±9.73 78.08±2.52 78.08±2.48 68.06±2.01 78.08±2.06 68.79±1.9 329.16±6.01 124±3.04 96±2.06 102±6.34 228.29±15.98 68.06 351.88 Table (4.6) the activity concentrations for 232Th, 238U and 40K-40 (Bq/ kg) in the shore sediment samples under study. Sample No. Activity concentrations (Bq/kg) 238 40 Th U K 1.43±0.07 3.39±2.68 27.14±3.52 3.27 ± 1.3 4.56 ± 1.28 71.29±2.25 2.78±0.06 2.85±0.93 55.32±2.54 2.02±0.82 3.12±1.14 33.89±4.60 1.78±0.08 3.19±1.97 21.04±3.22 2.12 ± 1.23 4.35 ± 2.26 27.58±3.12 2.63±1.83 4.05±2.01 31.21±3.34 3.07±1.04 3.99±2.03 58.74±2.56 2.65±0.46 4.73±1.65 49.22±2.55 2.13 ± 1.45 3.91 ± 1.62 32.77±2.85 2.14 ± 0.89 4.62 ± 2.25 37.96±2.78 3.13 ± 1.04 5.81 ±1.56 60.24±2.21 3.04 ± 0.79 6.42 ±2.13 51.25±2.35 10.02±1.61 13.08±1.74 12.39±3.62 2.56±0.76 3.44±1.59 53.09±5.11 3.47±0.35 3.63±0.67 80.75±7.35 4.11±1.15 5.01±1.10 78.94±4.61 5.82±2.10 4.67±2.34 71.65±3.42 1.60±0.01 2.32±0.84 24.04±1.2 3.69±0.86 4.65±0.19 40.24±2.8 3.17±0.19 4.59±0.18 45.94±3.2 1.43 2.32 12.39 10.02 13.08 80.75 232 H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H11 H12 H13 H14 H15 H16 H17 H18 H19 H20 mean±SD Min Max 63 Table (4.7) the activity concentrations for 232Th, 238U and 40K (Bq/ kg) in the agriculture soil samples under study Sample No. Activity concentrations (Bq/kg)\aqw 232 238 Th F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 mean±SD min max 11.56±1.49 14.53±2.6 15.88± 1.17 18.52± 2.67 14.62± 0.83 12.03±1.31 3.29±0.90 10.73±1.41 11.89±1.77 11.9±1.98 13.2±0.89 15.76±1.28 6.34±1.3 9.81±1.10 5.36±0.84 10.36±0.86 3.51±0.01 14.3±0.60 11.7±0.64 14.21±1.34 11.47±4.24 3.29 18.52 64 U 11.06±0.63 14.07 ± 4.37 18.65 ± 5.1 17.33 ± 4.72 14.23 ± 4.09 11.05±1.35 3.51±0.79 3.51±0.79 10.62±0.69 11.63±1.05 15.36±0.75 11.41±1.10 15.9±1.23 12.03±1.21 9.37±0.42 11.62±1.25 7.64±1.35 7.30±0.68 8.65±0.31 10.13±0.97 11.26±4.14 3.51 18.65 40 K 330.91±1.3 341.13±1.01 341.13±1.01 341.13±1.01 331.73±1.2 331.26±1.13 45.85±2.60 334.42±1.11 350.35±1.09 306.54±1.5 326.02±1.3 347.06±1.0 321±0.21 317±1.3 302±0.61 311±0.17 336±0.98 332±1.03 323±1.52 310±0.39 313.98±64.55 45.85 350.35 40K 238U w33 w31 w29 w27 w25 w23 w21 w19 w17 w15 w13 w7 w9 w11 w3 w5 232Th w1 Activity in Bq/Kg 50 45 40 35 30 25 20 15 10 5 0 Samples sites Fig. 4.5: Distribution of radioactive concentrations of 232Th, 238U and 40K in water. 400 Activity in Bq/Kg 350 300 250 200 40K 150 238U 100 232Th 50 0 s1 s3 s5 s7 s9 s11 s13 s15 s17 s19 Samples sites Fig. 4.6: Distribution of radioactive concentrations of 232Th, 238U and 40K in bottom sediment. 65 90 80 Activity in Bq/Kg 70 60 50 40 40K 30 238U 20 232Th 10 h1 h2 h3 h4 h5 h6 h7 h8 h9 h10 h11 h12 h13 h14 h15 h16 h17 h18 h19 h20 0 Samples sites Fig. 4.7: Distribution of radioactive concentrations of 232 Th,238 U and 40K in shore sediment. 400 Activity in Bq/Kg 350 300 250 200 K-40 150 U-238 100 Th-232 50 0 f1 f3 f5 f7 f9 f11 f13 f15 f17 f19 Samples sites Fig. 4.8: Distribution of radioactive concentrations of 232Th, U238 and 40K in soil. Considering the results obtained the following can be concluded: 66 4.3.1. Radioactivity concentrations in water samples: Table (4.4) shows that the activity concentrations for water samples from Qarun Lake ranges from 0.18 ± 0.03to 3.53 ± 0.21 Bq/kg for 232Th with an average value 2.19 Bq/kg, 0.95 ± 0.01to 6.57± 0.26 Bq/kg with an average value 2.92 Bq/kg for 238U and 1.03 ± 0.04to 43.74 ± 2.74 Bq/kg with an average value 16.12 Bq/kg for 40K. It is clear that the activity concentration values for 40K are higher than that of both 232Th and 238U series. 4.3.2. Radioactivity concentrations in bottom sediment samples: Table (4.5) shows that the activity concentrations for bottom sediment samples ranges from 5.74 ± 0.14 to 20.35 ± 1.01 Bq/kg for 232 Th with an average value 14.18 Bq/kg, 7.06 ± 0.28 to 30.15 ± 1.8 Bq/kg with an average value 20.99 Bq/kg for 238 U and from 68.06 ± 2.01to 351.88 ± 14.21 Bq/kg with an average value 244.68 Bq/kg for 40K. The world average radioactivity concentration ranges of 232 Th, 238 U and 40K in soils have been expressed as 35 (8-160), 35 (4-130) and 370 (100-700) Bq/kg respectively (UNSCEAR, 1993). It is clear that the radioactivity concentrations (for 232 Th, 238 U and 40 K) in soil samples from different sites under study can be considered as, taking into consideration the nature of the Egyptian soil. The radioactivity content in lake’s sediment depends on the rock type from which the sediment is formed, the atmospheric deposition (dry and wet), water flux and circulation in the lake, and the physical and chemical properties of the sediment. The correlation between 40K and 226Ra (238U) series and 232Th series may be explained by the competitive chemical behaviour and the concentration of the stable isotopes (K, Ra and Th) that could affect the adsorption of these ions on clay particle. 67 Generally, from the results of gamma measurements of Qarun Lake bottom sediment samples, it is concluded that there is no obvious variation in the radioactivity content of different bottom sediment samples along the studied area of the lake. This may be due to the bottom sediment nature which is composed of fine grains of sand, clay, silt or mud, capable of adsorbing, organic matter content, continuous addition of drain water, suspended matter and organic materials to the sediment and from fertilizers ( such as phosphate and organic fertilizers) and other chemicals used to increase the land fertility. 4.3.3. Radioactivity concentrations in shore sediment samples: Table (4.6) shows that the activity concentrations for shore sediment samples ranges from1.43 ± 0.07 to 10.02 ± 1.61(Bq/Kg) dry weight with an average value 3.14 ± 0.18(Bq/Kg) for 232 Th, 2.32 ± 0.84 to 13.08 ± 1.74(Bq/Kg) dry weight with an average value 4.59 ± 1.36(Bq/Kg) for 238U,and 12.39 ± 3.62 to 80.75 ± 7.35(Bq/Kg) dry weight with an average value 45.94 ± 4.03(Bq/Kg) for 40 K. 4.3.4. Radioactivity concentrations in soil samples: Table (4.7) shows that the activity concentrations for soil samples ranges from 3.29 ± 0.90 to 18.52 ± 2.67(Bq/Kg) dry weight with an average value 11.47 ± 2.13(Bq/Kg) for 232 Th, 3.51 ± 0.79 to 18.65 ± 5.1(Bq/Kg) dry weight with an average value 11.26 ± 1.95(Bq/Kg) for 238 U and 45.85 ± 2.60 to 350.35 ± 1.09 (Bq/Kg) dry weight with an average value 313.98 ± 3.02(Bq/Kg) ) for 40K. 68 4.4. Transfer factor of samples 232 Th, 238 U and 40 K from bottom sediment to water The concentration of a radionuclide associated with particulate material is generally related to the concentration of that radionuclide dissolved in the surrounding water. No radioisotopes were detected in the collected water samples except 40K. The bottom sediment-water distribution coefficient (Kd) is widely used to describe the partitioning of radionuclides between aqueous and solid phases (ElReefy, 2004) and is given by: Kd = Radioisotope content in sediment  Bq / Kg DW  Radioisotope content in water  Bq / L  It is useful for modelling the behaviour and distribution of radionuclides and for identifying those sites where they are likely to become concentrated. Radionuclides with relatively high solubility have low Kd values. Table (4.8) gives the transfer factors of 232 238 Th, U and 40 K for different samples. The bottom sediment to water transfer factors for 232Th, 238U and 40K were found to range from (2.63-10.75), (2.45-13.47) and (3.48-26.37) respectively. The average values of transfer factors for 232 Th, 238 U and 40 K is higher than 232 238 U this mean that 40K is mobile and has higher solubility compared to 232 238 U. 7.25 and 13.64 respectively. The transfer factor for 69 40 K were found to be 6.28, Th and Th and Table (4.8): Transfer factor for 232Th, 238U and 40K from bottom sediment to water samples. Samples Transfer factor 232 Thsediment / 232Thwater 238 Usediment / 238 40 Ksediment / 40Kwater 3.14 Uwater 6.51 9.78 13.47 14.02 3 5.13 7.82 12.48 4 9.83 12.94 26.37 5 6.51 12.99 17.03 6 5.46 5.65 9.87 7 6.57 6.71 22.49 8 5.13 4.79 6.14 9 9.79 9.81 23.41 10 4.13 5.98 23.24 11 2.89 4.35 3.73 12 6.11 4.89 17.31 13 10.75 9.60 16.99 14 6.88 3.04 3.48 15 9.17 7.42 10.86 1 4.42 2 70 4.5. Regression analysis of the data: Fig (4.9) shows the linear regression analysis of the observed values of 232 Th, 238 U and 40 K in bottom sediment and water. To establish a correlation between Th, U and K in bottom sediment and water, a linear correlation coefficient was used. For Th concentration, a linear correlation showed a coefficient of R2 = 0.037 with intercept = 2.48 and slope = -0.093. Similarly, U concentration showed a correlation coefficient of R2 = 0.063 with intercept = 3.64 and slope = -0.151. For K concentration showed a correlation coefficient of R2 = 0.019 with intercept = 22.72 and slope = -0.08842. In all cases, a poor degree of correlation observed indicating that concentration of Th, U and K in water not influenced too much by their concentration in bottom sediment (Abu-Khadra, 2011). Thus, it can be concluded that Th, U and K concentrations in water are not linearly related to their concentrations in bottom sediment. 71 U-238 conc (Bq/Kg) in water 7 y=2.016+0.05x 6 R=0.33 5 4 3 2 1 5 10 15 20 25 30 U-238 conc Bq/Kg in sediment y=1.05+0.07x 4.0 R=0.39 Th-232 conc (Bq/Kg) in water 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -0.5 4 6 8 10 12 14 16 18 20 22 Th-232 conc (Bq/Kg) in sediment y=9.82+0.04x K-40 conc (Bq/Kg) in water 50 R=0.37 40 30 20 10 0 50 100 150 200 250 300 350 K-40 conc (Bq/Kg) in sediment Figure (4-14). Linear regression analysis of the observed values of 232Th, 238 U and 40K in bottom sediment and water. 72 4.6. Dose assessment and Radiological effects: 4.6.1. Radium Equivalent Activity (Ra eq): For the purpose of comparing the radiological effect or activity of materials that contain 226Ra, 232Th and 40K by a single quantity, which takes into account the radiation hazards associated with them, a common index termed the radium equivalent activity (Raeq) is used. This activity index provides a useful guideline in regulating the safety standards on radiation protection for the general public residing in the area under investigation. The Raeq index represents a weighted sum of activities of the above mentioned natural radionuclides and is based on the estimation that 1 Bq/kg of 226Ra, 0.7 Bq/kg of 232Th, and 13Bq/kg of 40K produce the same gamma radiation dose rates. The index is given as: Raeq = CRa + 1.43CTh + 0.077Ck, Where CRa, CTh and Ck are the average activity concentration in sediment in Bq/kg of 226Ra, 232Th, and 40K, respectively. Calculated data of Raeq is presented in Table (4.9). The values for agriculture soil samples varied from 11.74 to 70.39 Bq/kg with an average value of 55.27 Bq/kg, which is far below the allowable limit (370 Bq/kg ) as recommended by the IAEA. 4.6.2. Gamma-absorbed dose rate (D): The gamma-absorbed dose rate in outdoor at 1m above the ground is calculated using the specific activities of 40 K, 226 Ra and 232 Th. The conversion factor used to calculate the absorbed dose rates (UNSCEAR , 1993) is given as: D (nGyh-1) = 0.0414CK + 0.461CRa +0.623 CTh 73 4.6.3. Effective dose rate: To estimate the annual effective dose rates, the conversion coefficient from absorbed dose in air to effective dose (0.7 Sv Gy-1) and outdoor occupancy factor (0.2).The effective dose rate in units of Sv μyr-1 was calculated by the following formula: Effective dose rate (μSv yr-1) =dose rate (nGyh-1) x 8760 h x 0.2 x 0.7 Sv Gy-1 x 10-3) 4.6.4. The external hazard index (Hex) can be defined as: Hex = ARa/370 + ATh/259+ AK/4810 ≤ 1, Where: ARa, ATh and AK are the specific activities of 226Ra, 232Th and 40K in Bqkg−1, respectively. This index value must be less than unity in order to keep the radiation hazard insignificant. Table (4.10) shows the external hazard index (Raeq), dose rate, effective dose rate and external hazard index (Hex) for agriculture soil samples. The highest observed annual effective dose is 41.47 μSv and the lowest value 6.82 μSv with a mean average value 31.56 μSv. This value is lower than the world-wide average annual effective dose which is approximately 70 μSv. In this study the value of the external hazard index is less than unity in all agriculture soil samples . 74 Table (4.10): The Raeq, dose rate, effective dose rate and external hazard index (Hex) for agriculture soil samples. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Raeq 65.16 68.63 55.61 51.71 60.68 53.07 11.74 61.12 53.76 70.39 55.39 55.98 49 50.47 40.28 50.38 38.53 53.31 50.25 54.32 Dose 31.52 31.87 15.07 25.47 29.4 25.98 5.56 29.66 26.29 33.82 26.97 27.18 22.78 24.78 20.16 24.69 19.62 26.02 24.65 26.35 75 Effective dose rate 38.65 39.09 18.48 31.24 36.06 31.86 6.82 36.38 32.25 41.47 33.08 33.34 27.94 30.39 24.69 30.28 24.06 31.91. 30.23 32.32 Hex 0.18 0.19 0.09 0.14 0.16 0.14 0.03 0.17 0.15 0.19 0.15 0.16 0.13 0.14 0.11 0.13 0.1 0.69 0.13 0.14 Summary and Conclusion Summary and conclusion: The present work deals with two parts: (1) Monitoring of radiation levels of different environmental samples in and around Qarun Lake El-Fayoum governate (Egypt). (2) Studying the chemical and physical characteristic of the studied samples. Bottom Sediment, water and shore sediment samples collected from Qarun Lake and soil samples collected from the agriculture land in the south area around the lake. The collected samples were pretreated, prepared and introduced for analysis using different techniques. Gamma-ray spectrometer was used to determine the natural radioactivity in the collected samples, X-ray Fluorescence spectrometry (XRF) used to identify and determine the concentrations of elements presents in (soild, powder and liquid samples) , Fourier transforms infrared spectroscopy (FTIR) is a very powerful analytical tool for examining both organic and inorganic materials it is a sensitive tool for mineral identification, Thermogravimetric analysis (TGA) instrumentation was used to measure carbonaceous components because of its potential to separate carbon and other components using heating programs , The X-ray diffractometer (XRD) analysis was undertaken to investigate qualitatively the composition of mineralogy in the studied samples. It is important to identify clay minerals, for example kaolinite, illite, montmorillonite, chlorite etc as they may influence the behaviors and properties of the studied samples, pH Meter to measure pH values and electrical conductivity. Physical and chemical parameters for Qarun Lake bottom sediment, water, shore sediment and soil samples have been carried out. The thermal analysis of the shore sediment , bottom sediment and soil samples appears as weight loss of moisture around 100°C and represented by a slight weight loss percent range from (1.32, 1.1 and 3) respectively. From 400 – 500o C a remarkable weight loss percent was observed for the soil sample due to the organic degradation of the local granitic rocks and phosphate fertilizers used in the cultivated soil sample. The X-ray diffraction (XRD) analysis explained as the following points. The peak in the low angle portion is that at 7.1 Å, attributable to kaolinite. It is most interesting to note that the intensity of prescribed peaks is comparatively more intense in the soil samples than the bottom sediment samples and disappear in case of shore sediment samples. The reason for this difference is based on clay content difference. It is interesting to note that the two patterns do not show the characteristic 10 Å peak of discrete illite. Quartz is appear in all studied samples as indicated by the intense peak at 3.33 Å and the rest of the series at 4.27, 2.46, 2.28, and 2.12 Å. It is interesting to point out again that the relative intensity of these peaks is higher in case of shore sediment samples than the other samples. Several characteristic peaks of the feldspars series are noticeable in the 3.2 Å regions of all studied samples. Peak intensity is much higher in case of shore sediment samples. The peak at 3.03 Å in all studied samples is due to calcite. Peak intensity is higher in shore sediment samples than other samples. The chemical compositional of the studied samples is determined by using X-ray fluorescence technique. The obtained data indicated that, the main elements present in all shore sediment, bottom sediment and soil samples are Si, group AII elements (Mg &Ca), Al, Fe and Na. In case of shore sediment sample the major element is Si+2, Al+3, Mg+2, Na+, Fe+2 and Ca+2 these elements represent about 87.5%. The infrared spectroscopy analysis for the studied sample showed that the sharp band at 1500 to 1000 cm−1 may be due to O–Si–O stretching in shore sediment sample and bottom sediment samples due to the free silicon group. The double bonds (e.g., C=O, C=C, and C=N) from 1800 to 1500 cm−1 in soil samples may referred to silicon compound having a carbonyl group attached to the silicon. The pH and electrical conductivity (EC) (Ω-1 cm-1) were measured for water, bottom sediment and soil samples. The pH values were on the alkaline side. The pH of Qarun lake water seems to vary in a very small range in the studied samples. The pH values for soil samples around 7 and it is less than bottom sediment due to the existence of acidic fertilizers in soil and also these value prove the existence of carbonate in soil that cleared in IR analysis .The electrical conductivity values for the soil samples is higher than the other studied samples may be due to the presence of expected movable salts. The bulk density and total porosity is also measured for soil and bottom sediment samples. For soil samples the average value of bulk density is 1.4 gm/cm3 and the average value of total porosity is 0.47. These values lie within those reported for other Egyptian soil samples. In case of bottom sediment samples the average value of bulk density is1.5 and the average value of total porosity are 0.43. The activity concentrations (Bq/L) for water samples ranged from 0.18 ± 0.03 to 3.53 ± 0.21 with an average value 2.19 for 232Th. The activity ranged from 0.95 ± 0.01 to 6.57± 0.26 with an average value 2.92 for 238U and ranged from 1.03 ± 0.04 to 43.74 ± 2.74 with an average value 16.12 for 40K. While The mean specific activities of 238U series, 232Th series and 40K in the bottom sediment samples ranged from 7.06±0.28 to 30.15±1.8 Bq/Kg with an average value 20.37Bq/kg for 238U and it ranged from 5.9±0.14 to 20.35±1.01 with an average value 14.18 for 232Th.it ranged from 68.06±2.01 to 351.88±4.82 with an average value 244.68 for 40K. In case of shore sediment samples the mean specific activities of samples ranged from 1.43 ± 0.07 to 10.02 ± 1.61 with an average value 3.14±0.07 for 232Th, also the activity ranged from 2.32 ± 0.84 to 13.08 ± 1.74 with an average value 4.59±1.36 for 238 U and ranged from 12.39 ± 3.62 to 80.75±7.35 with an average value 45.94 for 40K. While in soil samples were ranged from 3.29 ± 0.90 to 18.52 ± 2.67 with an average value 11.47±2.13 for 232Th ,while ranged from 3.51 ± 0.79 to 18.65 ± 5.1 with an average value 11.26±1.95 for 238U , and the activity ranged from 45.85 ± 2.60 to 350.35 ± 1.09 with an average value 313.98±3.02 for 40K. For the agriculture soil samples the values of radium equivalent activity varied from 11.74 to 70.39 Bqkg–1 with an average value of 55.27 Bqkg–1, which is far below the allowable limit (370 Bqkg –1 ) as recommended by the IAEA. The highest observed annual effective dose is 41.47 μSv and the lowest value 6.82 μSv with a mean average value 31.56 μSv. This value is lower than the world-wide average annual effective dose which is approximately 70 μSv . In this study the value of the external hazard index is less than unity in all agriculture soil samples . 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Niigata Ken Eisei Kogai kenkyusho Nenpo, Vol. 10, pp. 96101, (1995). 87 ‫الملخص العزبى‬ ‫تهدف هذة الدراسة إلى ‪:‬‬ ‫)ثذيشح‬ ‫رذذيذ ٍغز٘‪ ٙ‬اىزي٘س اإلشؼبػ‪ٗ ٚ‬ر٘صيؼخ اىَنبّ‪ ٚ‬ف‪ٍْ ٚ‬طقخ اىجذش‬ ‫قبسُٗ) ثغشض اىزؼشف ػي‪ٍ ٚ‬صبدس ٍٗغبساد اىْ٘يبد اىَشؼخ‪ٗ ,‬رقييٌ رأصيشارٖب‬ ‫ػي‪ ٚ‬صذخ االّغبُ‪.‬‬ ‫ثبألظبفخ إى‪ ٚ‬رىل رٖذف اىذساعخ إى‪ ٚ‬اىذص٘ه ػي‪ٍ ٚ‬ؼيٍ٘بد د٘ه ػالقخ رشميضاد‬ ‫اىْظبئش اىَشؼخ اىَخزيفخ ٍغ خ٘اص مو ٍِ اىزشثخ ٗسٗاعت ثذيشح قبسُٗ‪.‬‬ ‫ٗمزىل ٗظغ خشيطخ ٍشجؼيخ ىيخيفيخ اإلشؼبػيخ ه ثذيشح قبسُٗ دز‪ ٚ‬يَنِ ٍقبسّزٖب‬ ‫ثأ‪ ٙ‬صيبدح ف‪ ٚ‬اىَغز٘‪ ٙ‬اإلشؼبػ‪ ٚ‬اىْبرج ٍِ ا‪ ٙ‬رغشة إشؼبػ‪ ٚ‬أٗ ٍِ اىزغبقػ ف‪ٚ‬‬ ‫اىَغزقجو أٗ ّزيجخ ىزْفيز ثؼط اىَششٗػبد ف‪ ٚ‬اىَْطقخ اىز‪ ٚ‬يَنِ اُ رؤصش ػي‪ ٚ‬ثيئخ‬ ‫اىَْطقخ‪ .‬ىزا قذ رٌ اجشاء ٍغخ رفصيي‪ ٚ‬ىَظبٕش اىزي٘س ٗقيبط ٍؼذالرخ ٍِ ثذايخ‬ ‫اىجذيشح ػْذ اىشمِ اىشَبه اىششق‪(ٚ‬خضاُ اىجبرظ) إى‪ّ ٚ‬قطخ اىَْزصف ىيشبغئ‬ ‫اىجْ٘ث‪ (ٚ‬خضاُ اى٘اد‪.)ٙ‬‬ ‫ٗقذ رٌ رجَيغ ػيْبد (ٍبء‪ -‬سٗاعت) ٍِ اىجذيشح ٗػيْبد(رشثخ) ٍِ اىَْطقخ‬ ‫اىضساػيخ اىز‪ ٚ‬رذيػ ثبىجذيشح ٍِ اىجْ٘ة ٗاىجْ٘ة اىششق‪ٗ .ٚ‬قذ ثيغ ػذد اىؼيْبد‬ ‫اىز‪ ٚ‬رٌ إخزيبسٕب ‪ 93‬ػيْخ ٍ٘صػخ مبىزبى‪:ٚ‬‬ ‫‪ 33‬ػيْخ ٍيبح ٍِ ثذيشح قبسُٗ ٗقذ رٌ اخزيبس ‪20‬ػيْخ سع٘ثيبد قبػيخ ٍِ‬‫ّفظ أٍبمِ ػيْبد اىَيبح اىغطذيخ‪.‬‬ ‫ ‪20‬ػيْخ سع٘ثيبد شبغئيخ ٗمزىل ‪ 20‬ػيْخ رشثخ صساػيخ‪.‬‬‫ٗرٌ دساعخ اىَغز٘يبد االشؼبػيخ ىٖزٓ اىؼيْبد ٗرىل ثبعزخذاً جٖبص‬ ‫اىجيشٍبّيً٘ ػبى‪ ٚ‬اىْقبٗح ىزذييو اىطيف اىجبٍ‪ٗ ٚ‬رىل ثؼذ ٍؼبيشرخ ‪ .‬رٌ رقذيش رشميض‬ ‫ّ٘يذاد اىج٘ربعيً٘ ‪ٗ (40)-‬اىض٘سيً٘ ‪ٗ (232)-‬اىي٘ساّيً٘‪(238)-‬ث٘دذح اىجينشه‬ ‫‪/‬ميي٘ جشاً ٗمَيخ اىشاديً٘ ‪ (226)-‬اىَنبفئخ ثينشه ‪/‬ميي٘جشاً‪.‬‬ ‫ٗرٌ دغبة ثؼط ٍؼبٍالد االصبس االشؼبػيخ ىؼيْبد اىزشثخ اىضساػيخ ّظشا‬ ‫ىزأصيشٕب ػي‪ ٚ‬صذخ االّغبُ ٍِٗ ٕزح اىَؼبٍالد ٍؼذه اٍزصبص اىجشػخ (ّبّ٘‬ ‫جشا‪/ ٙ‬عبػخ ) ٗمزىل ٍؼذه اىجشػخ اىفؼبىخ ( ٍينشٗ عيفشد ‪/‬عْخ) مَب رٌ دغبة‬ ‫ٍؤشش اىخطش اىخبسج‪(ٚ‬ثينشه ‪/‬ميي٘ جشاً) ٗقذ رجيِ اُ ٕزح اىقيبعبد اقو ٍِ اىذذ‬ ‫اىَغَ٘ح ثٔ ٍِ قجو اى٘مبىخ اىذٗىيخ ىيطبقخ اىزسيخ‪ٗ .‬ع٘ف يزٌ اعزخذاً ٕزح اىقيبعبد‬ ‫مَشجؼيخ ىزقييٌ ا‪ ٙ‬رغيش ف‪ ٚ‬اىخيفيخ االشؼبػيخ ىٖزح اىَْطقخ‪.‬‬ ‫ٗىذساعخ خ٘اص اىزشثخ ٗاىشٗاعت قذ رٌ اعزخذاً اىزذييو ثبعزخذاً اشؼخ أمظ‬ ‫ٍٗطيبفيخ ف٘سيش ثبالشؼخ رذذ اىذَشاء مَب رٌ قيبط مال ٍِ االط اىٖيذسٗجيْ‪ٚ‬‬ ‫ٗاىز٘صيييخ اىنٖشثيخ ٗاىنضبفخ اىظبٕشيخ ٗمزىل اىَغبٍيخ اىنييخ ٗرٌ دغبة اىَشمجبد‬ ‫اىؼع٘يخ ىيؼيْبد اىصيجخ ثبعزخذاً رقْيخ اىزذييو اىذشاس‪.ٙ‬‬ ‫ٍِٗ اىْزبئج اىَؼَييخ ىٖزح اىذساعبد أٍنِ اعزخالص ٍب يي‪:ٚ‬‬ ‫‪ -1‬عالعو اىْشبغ االشؼبػ‪ ٚ‬اىطجيؼ‪( ٚ‬اىي٘ساّيً٘‪ٗ 238 -‬اىض٘سيً٘‪ٗ )232 -‬مزىل‬ ‫اىج٘ربعيً٘ ‪,40 -‬أظٖشد ّشبغيخ إشؼبػيخ ف‪ ٚ‬ػيْبد اىَيبح رزشٗاح ٍِ‬ ‫)‪ ) 0.95±0.01‬اى‪ )3.01±1.01 ) ٚ‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ ىيي٘ساّيً٘‪-‬‬ ‫(‪ٗ .)238‬رزشاٗح ٍِ ( ‪ )0.18±0.03‬اى‪ ) 5.32±1.5 ( ٚ‬ثينشيو ىنو ميي٘جشاً‬ ‫ٗرزشاٗح ٍِ ( ‪ )13.38±0.87‬اى‪ ) 35.02±4.15 ( ٚ‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ‬ ‫ىيج٘ربعيً٘‪ٗ .)40( -‬ثبىْغجخ ىؼيْبد اىشٗاعت اىقبػيخ رزشاٗح اىْشبغيخ اإلشؼبػيخ ٍِ‬ ‫(‪ ) 7.06±0.28‬إى‪ ) 29.89±1.19 ( ٚ‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ ىيي٘ساّيً٘‪-‬‬ ‫(‪.) 238‬‬ ‫ٗرزشاٗح ٍِ ( ‪ )5.74±0.14‬اى‪ )20.35±1.01 ( ٚ‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ‬ ‫ىيض٘سيً٘‪ٗ. )232(-‬رزشاٗح ٍِ ( ‪)68.06±2.01‬اى‪) 344.61±11.6(ٚ‬ثينشيو ىنو‬ ‫ميي٘جشاً ثبىْغجخ ىيج٘ربعيً٘‪.40-‬‬ ‫(‪ )2.32±0.84‬اى‪ٚ‬‬ ‫ٗاىْشبغيخ اإلشؼبػيخ ىيشٗاعت اىشبغئيخ رزشاٗح ٍِ‬ ‫(‪ )13.08±1.74‬ثينشيو ىنو ميي٘جيشاً ثبىْغجخ ىيي٘ساّيً٘ ‪ٗ.)238(-‬رزشاٗح ٍِ‬ ‫(‪ ) 1.43±0.07‬اى‪ ) 10.02±1.61( ٚ‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ ىيض٘سيً٘ ‪-‬‬ ‫(‪ٗ)232‬رزشاٗح ٍِ ( ‪ )12.39±3.62‬اى‪ )80.75±7.35 ( ٚ‬ثينشيو ىنو ميي٘جشاً‬ ‫ثبىْغجخ ىيج٘ربعيً٘‪.)40(-‬‬ ‫ٗاىْشبغيخ اإلشؼبػيخ ىؼيْبد اىزشثخ رزشاٗح ٍِ (‪ ) 3.51±0.79‬اى‪) 18.65±5.1( ٚ‬‬ ‫ثينشيو ىنو ميي٘جشاً ثبىْغجخ ىيي٘ساّيً٘ ‪ٗ .)238(-‬رزشاٗح ٍِ ( ‪ )3.29±0.90‬اى‪ٚ‬‬ ‫(‪ٗ.)232‬رزشاٗح‬‫(‪ ) 18.52±2.67‬ثينشيو ىنو ميي٘جشاً ثبىْغجخ ىيض٘سيً٘‬ ‫ٍِ(‪ ) 45.85±2.60‬اى‪) 350.35±1.09( ٚ‬‬ ‫ىيج٘ربعيً٘‪.) 40(-‬‬ ‫ثينشيو ىنو ميي٘جشاً ثبىْغجخ‬ ‫ٗقذ ى٘دع أُ اىْشبغيخ اإلشؼبػيخ ف‪ ٚ‬دبىخ ػيْبد اىَيبح أقو ٍْٖب ف‪ ٚ‬اىؼيْبد‬ ‫األخش‪ٗ ٙ‬أُ اىْشبغيخ اإلشؼبػيخ ف‪ ٚ‬دبىخ اىزشثخ ٗاىشٗاعت اىقبػيخ أػي‪ٍِ ٚ‬‬ ‫اىشٗاعت اىشبغئيخ ٍَب يشعخ اُ ٍذز٘‪ ٙ‬اىشٗاعت ٍِ اىْ٘يذاد اىَشؼخ يؼزَذ ػي‪ٚ‬‬ ‫ّ٘ع اىصخ٘س اىَنّ٘خ ىخزح اىشٗاعت ٗأيعب اىخ٘اص اىطجيؼيخ ٗاىنيَيبئيخ ىٖزح‬ ‫اىشٗاعت‪.‬‬ ‫ٗرٌ دغبة ثؼط ٍؼبٍالد االصبس االشؼبػيخ ىؼيْبد اىزشثخ اىضساػيخ ّظشا‬ ‫ىزأصيشٕب ػي‪ ٚ‬صذخ االّغبُ ٍِٗ ٕزح اىَؼبٍالد اىْشبغيخ اىَنبفئخ ىيشاديً٘‪226 -‬‬ ‫ٗاىقيٌ رزشاٗح ٍِ ‪11.47‬اى‪70.39 ٚ‬ثينشيو ىنو ميي٘جشاً ٗثَز٘عػ يؼبده‬ ‫‪55.27‬ثينشيو ىنو ميي٘جشاً ديش اُ ٕزح اىقيَخ أقو ٍِ اىذذ اىَغَ٘ح ( ‪370‬ثينشيو‬ ‫ىنو ميي٘جشاً) ثخ ٍِ قجو اى٘مبىخ اىذٗىيخ ىيطبقخ اىزسيخ‪ٗ .‬مزىل ٍؼذه اىجشػخ اىفؼبىخ‬ ‫( ٍينشٗ عيفشد ‪/‬عْخ) ٍز٘عػ قيَزخ ‪ٍ 31.56‬ينشٗ عيفشد ٕٗزح اىقيَخ أقو ٍِ‬ ‫اىَز٘عػ اىؼبىَ‪. ٚ‬مَب رٌ دغبة ٍؤشش اىخطش اىخبسج‪( ٚ‬ثينشه ‪/‬ميي٘ جشاً) ٗقذ‬ ‫رجيِ اُ ٕزح اىقيبعبد اقو ٍِ اىذذ اىَغَ٘ح ثٔ ٍِ قجو اى٘مبىخ اىذٗىيخ ىيطبقخ اىزسيخ‪.‬‬ ‫ٗع٘ف يزٌ اعزخذاً ٕزح اىقيبعبد مَشجؼيخ ىزقييٌ ا‪ ٙ‬رغيش ف‪ ٚ‬اىخيفيخ االشؼبػيخ ىٖزح‬ ‫اىَْطقخ‪.‬‬ ‫‪ -2‬يظٖش اىزذييو اىذشاس‪ ٙ‬ىؼيْبد اىشٗاعت اىشبغئيخ ٗاىشٗاعت اىقبػيخ‬ ‫ٗمزىل ػيْبد اىزشثخ اّخ خاله اه ‪100‬دسجخ اىَئ٘يخ االٗى‪ ٚ‬دذس فقذ ف‪ ٚ‬اى٘صُ‬ ‫ثغجت رطبيش ثخب س اىَبء ف‪ ٚ‬اىؼيْبد ٗدذس ٕزا اىفقذ ف‪ ٚ‬اى٘صُ ثْغت‬ ‫(‪).1.32,1.1,3‬ػي‪ ٚ‬اىز٘اى‪ٗ .ٚ‬ف‪ ٚ‬دسجخ اىذشاسح ٍِ ‪500-400‬دسجخ ٍئ٘يخ دذس‬ ‫فقذ ٗاظخ ف‪ ٚ‬اى٘صُ ثبىْغجخ ىؼيْبد اىزشثخ ٗيشجغ رىل اى‪ ٚ‬اىزذٕ٘س اىؼع٘‪ٙ‬‬ ‫ىيصخ٘س اىجشاّيزيخ ٗمزىل ثغجت األعَذح اىف٘عبريخ اىَغزخذٍخ ف‪ ٚ‬اىزشثخ اىضساػيخ‪.‬‬ ‫‪Å7.1‬‬ ‫‪ٗ -3‬أٗظخ رذييو دي٘د األشؼخ اىغيْيخ اّخ ْٕبك قَخ ػْذ اىضاٗيخ‬ ‫ٗيشجغ ظٖ٘سٕب ى٘ج٘د اىن٘ىْيذ ٗرظٖش ٕزح اىقَخ ثشذح ف‪ ٚ‬دبىخ ػيْبد اىزشثخ ػْٖب‬ ‫ف‪ ٚ‬دبىخ ػيْبد اىشٗاعت اىقبػيخ ثيَْب رخزف‪ ٚ‬ف‪ ٚ‬ػيْبد اىشٗاعت اىشبغئيخ ثغجت‬ ‫غجيؼزٖب اىشٍييخ‪ٗ .‬اىن٘اسرض يظٖش ف‪ ٚ‬مو اىؼيْبد اىَذسٗعخ ػْذ قَخ ‪ٗ 3.33 Å‬ىنِ‬ ‫ٗج٘دح ف‪ ٚ‬ػيْبد اىشٗاعت اىشبغئيخ اػي‪ٍْ ٚ‬خ ف‪ ٚ‬ثبق‪ ٚ‬اىؼيْبد ‪.‬ػذح قيٌ ٍَيضح‬ ‫ىيفيغجبس رظٖش ف‪ ٚ‬مو اىؼيْبد اىَذسٗعخ ػْذ قَخ‬ ‫ػيْبد اىشٗاعت اىشبغئيخ‪.‬‬ ‫‪ٗ Å3.2‬ىنِ رظٖش ث٘ظ٘ح ‪ٙ‬‬ ‫‪ٗ -4‬قذ رٌ رذذيذ اىَبدح اىنيَيبئيخ اىزشميجيخ ىيؼيْبد اىَذسٗعخ ثبعزخذاً رقْيخ‬ ‫االشؼخ اىغيْيخ اىٍ٘يعيخ ٗأشبسد اىجيبّبد اُ اىؼْبصش اىشئيغيخ اىَنّ٘خ ىيؼيْبد ٕ‪ٚ‬‬ ‫اىغيينُ٘ ٗػْبصش اىَجَ٘ػخ اىضبّيخ مبىَغْبعيً٘ ٗاالىَّ٘يً٘ ٗاىص٘ديً٘‬ ‫ٗاىنبىغيً٘‪.‬‬ ‫‪ٗ -5‬أظٖش اىزذييو اىطيف‪ ٚ‬ثبالشؼخ رذذ اىذَشاء ٗج٘د ساثطخ ق٘يخ ف‪ٚ‬‬ ‫اىَْطقخ ٍِ ‪ٗ1000-1500cm-1‬رىل ى٘ج٘د اىغيينُ٘ ف‪ ٚ‬ػيْبد اىشٗاعت اىشبغئيخ‬ ‫‪cm-1‬‬ ‫يييخ اىشٗاعت اىقبػيخ ثيَْب ف‪ ٚ‬دبىخ ػيْبد اىزشثخ يظٖش سٗاثػ صْبئيخ ٍِ‬ ‫‪ٗ1800-1500‬رىل ى٘ج٘د ٍجَ٘ػخ اىنشثّ٘يو ٍصبدج‪ ٚ‬ىيغيينُ٘‪.‬‬ ‫‪ -6‬رٌ قيبط االط اىٖيذسٗجيْ‪ٗ ٚ‬اىز٘صيييخ اىنٖشثيخ ىيؼيْبد اىَذسٗعخ ٗقيٌ‬ ‫االط اىٖيذسٗجيْ‪ ٚ‬ف‪ ٚ‬اىجبّت اىقي٘‪ٗ.ٙ‬قيٌ االط اىٖيذسٗجيْ‪ ٚ‬ثبىْغجخ ىؼيْبد اىَيبح‬ ‫ٍزقبسثخ جذاٗقيٌ االط اىٖيذسٗجيْ‪ ٚ‬ىؼيْبد اىزشثخ رزشاٗح د٘ه ‪ ٕٚٗ7‬اقو ٍْٖب ف‪ٚ‬‬ ‫دبىخ اىشٗاعت اىقبػيخ ٗرىل ى٘ج٘د االعَذح اىذَعيخ ف‪ ٚ‬اىزشثخ اىضساػيخ ٕٗزح‬ ‫اىقيَخ رضجذ ٗج٘د اىنشثّ٘بد ف‪ ٚ‬اىزشثخ مَب ظٖش ف‪ ٚ‬اىزذييو اىطيف‪ ٚ‬ثبالشؼخ رذذ‬ ‫اىذَشاء‪ٗ .‬قيٌ اىز٘صيييخ اىنٖشثيخ ىؼيْبد اىزشثخ اػي‪ ٍِ ٚ‬ثقيخ اىؼيْبد ٗرىل ى٘ج٘د‬ ‫االٍالح ٗثبىشج٘ع اى‪ ٚ‬اىْشبغيخ اإلشؼبػيخ ىؼْصش اىج٘ربعيً٘‪40 -‬ع٘ف ّجذ قيَخ‬ ‫اػي‪ ٍِ ٚ‬ثيقخ اىؼيْبد االخش‪.ٙ‬‬ ‫‪ٗ-7‬رٌ قيبط اىنضبفخ اىظبٕشيخ ٗاىَغبٍيخ اىنييخ أيعب ىؼيْبد اىزشثخ‬ ‫ٗاىشع٘ثيبد ٗثبىْغجخ ىؼيْبد اىزشثخ اىقيَخ اىَز٘عطخ ىينضبفخ ىينضبفخ اىظبٕشيخ ٕ‪ٚ‬‬ ‫‪1.4‬جشاً ىنو عْزيَزش ٍنؼت ٗاىقيَخ اىَز٘عطخ ىيَغبٍيخ اىنييخ ٕ‪ٕٗ0.47 ٚ‬زح اىقيٌ‬ ‫رقغ ٍْبعجخ ٍغ اىزشثخ اىَصشيخ‪.‬‬ ‫‪1.5‬جشاً ىنو‬ ‫ف‪ ٚ‬دبىخ اىشٗاعت اىقبػيخ اىقيَخ اىَز٘عطخ ىينضبفخ اىظبٕشيخ‬ ‫عْزيَزش ٍنؼت ٗاىقيَخ اىَز٘عطخ ىيَغبٍيخ اىنييخ ‪.0.43‬‬ ‫دراست النشبط اإلشعبعى الطبيعى وأخطبرة لبعض‬ ‫العينبث البيئيت‬ ‫رسبلت هقدهت للحصول على درجت الوبجيستيز فى‬ ‫الفيزيبء‬ ‫هقدهت الي‬ ‫كليت العلوم‬ ‫جبهعت الفيوم‬ ‫هن‬ ‫نبديت عبد الفتبح قطب السيد‬ ‫المعيد بقسم الوقبية اإلشعبعية‬ ‫المعمل الحبر‪-‬هيئة الطبقة الذرية المصزية‬ ‫‪2014‬‬ ‫جبهعت الفيوم‬ ‫كليت العلوم‬ ‫قسن الفيزيبء‬ ‫دراست النشبط اإلشعبعى الطبيعى وأخطبرة لبعض العينبث‬ ‫البيئيت‬ ‫لجنت اإلشزاف‪-:‬‬ ‫ا‪ .‬د‪ /.‬عبد الوحسن هحود ببشت‬ ‫قسن الفيزيبء‪-‬كليت العلوم‬ ‫جبهعت الفيوم‬ ‫ا‪.‬د‪ /.‬طبرق هحود سلين الزقلت‬ ‫قسن الوقبيت اإلشعبعيت‪-‬الوعول الحبر‬ ‫هيئت الطبقت الذريت‬