Natural radioactivity levels and associated health hazards from the terrestrial ecosystem in Rosetta branch of the River Nile,Egypt

Twenty soil and 25 sediment samples were collected from the banks and bottom of the River Nile in the surroundings of biggest cities located close to it. Natural radioactivity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K have been evaluated for all samples by means of γ spectrometric analysis. The radioactivity levels of soil and sediment samples fall within the internationally recommended values. Nevertheless, high natural background radiation zones are detected in the Kafr El-Zayat region due to the presence of a fertilizer factory, and in the Rosetta region due to the presence of black sand deposits. The absorbed dose rate, the γ index and excess life time cancer risk are calculated. High values for some of the radiation health parameters are detected in the Kafr El-Zayat and Rosetta regions representing a serious problem to public health because the soil and sediment are used as constructing material for buildings. Furthermore, the isotope analysis of uranium for representative collected sediment samples via α spectrometry showed average specific activities of 18.7?±?3.6, 0.087?±?0.0038 and 18.6?±?3.8 Bq kg^–1 for ²³⁴U, ²³⁵U and ²³⁸U, respectively. In general, these values confirm the balance in the isotopic abundance of U isotopes.     

Interpolated mapping and investigation of environmental radioactivity levels in soils and mushrooms in the Middle Black Sea Region of Turkey

The activity concentration of natural (²³⁸U, ²³²Th, and ⁴⁰K) and artificial (¹³⁷Cs) radionuclides was determined in 50 samples (obtained from the same station) from various species of mushrooms and soil collected from the Middle Black Sea Region (Turkey). The activities of ²³⁸U, ²³²Th, ⁴⁰K, and ¹³⁷Cs were found as 84 ± 16, 45 ± 14, 570 ± 28, and 64 ± 6?Bq?kg^–1 (dry weight), respectively, in the mushroom samples and as 51?±?6, 41?±?6, 201?±?11, and 44?±?4?Bq?kg^–1, respectively, in the soil samples for the entire area of study. The results of all radionuclide activity measurements, except those of ²³⁸U and ²³²Th in the mushroom samples, are consistent with previous studies. In the soil samples, the mean values of ²³⁸U and ²³²Th are above the world mean, and the activity mean of ⁴⁰K is below the world mean. Finally, the activity estimation was made with both the soil and mushroom samples for unmeasured points within the study area by using the ordinary kriging method. Radiological distribution maps were generated.     

Assessment of radiological hazard parameters due to natural radioactivity in soils from granite-rich regions in Kütahya Province,Turkey

The analysis of natural radioactivity from ²³⁸U, ²³²Th and ⁴⁰K in 357 soil samples collected from the province of Kütahya was carried out using a NaI(Tl) gamma-ray spectroscopy system at the Nuclear Physics Research Laboratory, Dumlup?nar University, Kütahya, Turkey. The specific activities of ²³⁸U, ²³²Th and ⁴⁰K in the soil samples were evaluated. From the activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K, the total absorbed outdoor gamma-ray dose rates and the corresponding annual effective dose rates were determined. The corresponding values of the external and internal hazard indices of all the soil samples were also calculated. The external gamma-ray dose rate at 1 m above the ground was directly measured at each collected soil sample location. The results obtained in this study were compared within the limits of values obtained in other cities of Turkey, those in other countries. Radiological maps of Kütahya Province were constructed from the results of this study.     

The influence of the nature of soil and plant and pollution on the 238U, 232Th, 222Rn and 220Rn concentrations in various natural honey samples using nuclear track detectors: Impact on the adult consumers

²³⁸U and ²³²Th concentrations as well as ²²²Rn and ²²⁰Rn α-activities per unit volume were measured in various natural honey samples collected from different regions in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). These radionuclides were also measured in soils, plant flowers and nectar solutions corresponding to the honey samples studied. In addition, these radionuclides were measured in different imported honey samples. The measured ²³⁸U, ²³²Th, ²²²Rn and ²²⁰Rn concentrations ranged from (1.5±0.1) mBq kg⁻¹ to (10.6±0.6) mBq kg⁻¹, (1.1±0.1) mBq kg⁻¹ to (4.2±0.2) mBq kg⁻¹, (1.5±0.1) Bq kg⁻¹ to (10.6±0.6) Bq kg⁻¹ and (1.1±0.1) Bq kg⁻¹ to (4.2±0.2) Bq kg⁻¹ for the honey samples studied, respectively. Annual ²³⁸U, ²³²Th and ²²²Rn intakes by Moroccan adults from the consumption of honey were assessed. The influence of the nature of soil and plant on the ²³⁸U and ²³²Th contents of the studied honey samples was investigated. These measurements were completed by an investigation of the ²³⁸U and ²³²Th transfer between soils and plant flowers and that between plant flowers and honey, and also by the investigation of the influence of pollution due to different material dusts on ²³⁸U, ²³²Th and ²²²Rn in the honey samples studied. Committed equivalent doses due to the annual intake of ²³⁸U, ²³²Th and ²²²Rn were evaluated in the organs of adult members of the Moroccan rural population from the ingestion of the honey samples. The maximum total committed effective dose due to ²³⁸U, ²³²Th and ²²²Rn from the ingestion of natural honey by the Moroccan rural population was found to be equal to 0.64 μ Sv y⁻¹.     

Natural radioactivity and radiation hazards assessment of soil samples from the area of Tuzla and Lukavac,Bosnia and Herzegovina

The results of activity concentration measurements of natural occurring radioactive nuclides ²³⁸U, ²³⁵U, ²³²Th, ²²⁶Ra, and ⁴⁰K in surface soil samples collected in the area of cities Tuzla and Lukavac, northeast region of Bosnia and Herzegovina were presented. Soil sampling was conducted at the localities that are situated in the vicinity of industrial zones of these cities. The measured activity was in the range from (8?±?4) to (95?±?28) Bq kg^–1 for ²³⁸U, from (0.41?±?0.06) to (4.6?±?0.7) Bq kg^–1 for ²³⁵U, from (7?±?1) to (66?±?7) Bq kg^–1 for ²³²Th, from (6?±?1) to (55?±?6) Bq kg^–1 for ²²⁶Ra, and from (83?±?12) to (546?±?55) Bq kg^–1 for ⁴⁰K. In order to evaluate the radiological hazard of the natural radioactivity for people living near industrial zones, the absorbed dose rate, the annual effective dose and the radium equivalent activity have been calculated and compared with the internationally approved values.     

Energy levels in even actinide isotopes from (t,p) reactions

Energy levels in^{232, 234}Th,^{236, 238, 240}U and in²⁵⁰Cm have been measured using the (t, p) reaction. Angular distributions were obtained for the^{234, 238}U targets and evidence for second order effects in the direct reaction mechanism was found.     

Energy Dependence of the Most Stable Nuclei Production in Proton-Induced 238U and 232Th Fission

Using the available experimental data, production cross sections of the most stable nuclei have been calculated for the proton-induced fission of ²³⁸U and ²³²Th at 12, 20, 35, 50, 96 MeV in case of ²³⁸U and at 8, 9.3, 12, 19.55, 32.2, 44.7, 53 MeV for ²³²Th. The analysis has been carried out for the fission fragment mass ranges corresponding to N/Z ratios in the ranges 1.33 ± 0.09 and 1.32 ± 0.08 for ²³⁸U and ²³²Th respectively. Results have been compared with the ones generated indirectly by employing GEF nuclear reaction code, version 2017/1.1. From the production cross sections point of view, for the same energy, ²³²Th is found to be a better target than ²³⁸U for producing nuclei A around the symmetric mass peak, while ²³⁸U comes out to be a better one than ²³²Th for producing the fission fragments around the asymmetric peaks of the mass distribution.

     

Measurement of uranium and its isotopes at trace levels in environmental samples using mass spectrometry

Actinides have widely entered the environment as a result of nuclear accidents and atmospheric weapon testing. These radionuclides, especially uranium, are outstanding radioactive pollutants, due to their high radiotoxicity and long half-lives. In addition to this, since depleted uranium (DU) has been used in the Balkan conflict in 1999, there has been a concern about the possible consequences of its use for the people and environment. Therefore, accurate, precise and simple determination methods are necessary in order to evaluate the human dose and the concentration and effects of these nuclides in the environment. The principal isotopes of uranium e.g. ²³⁵U and ²³⁸U are of primordial origin and ²³⁴U present in radioactive equilibrium with ²³⁸U. ²³⁶U occurs in nature at ultra trace concentrations with a ²³⁶U: ²³⁸U atom ratio of 10⁻¹⁴. Concentrations of uranium in soil samples were determined using inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratios of uranium were measured using a thermal ionisation mass spectrometer. Radioactive dis-equilibrium of ²³⁴/²³⁸U, depletion of ²³⁵/²³⁸U and significant evidence of ²³⁶U/²³⁸U were noticed in soil samples.      

Radioactivity of sand,groundwater and wild plants in northeast Sinai,Egypt

The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km² in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among ²³⁸U, ²³⁴Th, and ²²⁶Ra isotopes and low significant correlations between the concentrations of ²³⁸U-series and ²³²Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. The range of concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in water samples collected from five wells were<0.4–0.16,<0.4–0.13, and<0.15–1.62 Bq l^?1, respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h^?1. The Ra_eq activities of the sands are lower than the recommended maximum value of 370 Bq kg^?1 criterion limit for building materials.     

Radiological and hyperfine characterization of soils from the Northeastern region of the Province of Buenos Aires, Argentina

The activity concentrations of both natural (²³⁸U and ²³²Th chains and ⁴⁰K) and anthropogenic (¹³⁷Cs) radionuclides down along the soil profile have been determined in soil samples collected from inland and coastal areas of the La Plata River, located in the Northeastern region of the Province of Buenos Aires, Argentina. These studies were complemented with ⁵⁷Fe Mössbauer spectroscopy characterization, pH, texture and organic carbon content measurements. From Mössbauer results, the sample compositions differ from one area to the other. Spectra from both soil samples are dominated by the Fe^3+? paramagnetic signal. For soil samples from the coastal area, the ??-Fe₂O₃ contribution is lower, Fe₃O₄ was not detected, and the relative areas of each spectral contribution are nearly constant with depth. For samples from the inland area, the Fe^3+? paramagnetic fraction increases up to 82%, mainly at the expense of the magnetically ordered phase. The main observed activity originates from the decay of ⁴⁰K (540?C750 Bq/kg), followed by ²³⁸U (60?C92 Bq/kg) and ²³²Th (37?C46 Bq/kg) chains. The activity of ²³⁵U was in all the cases lower than the detection limit (L_D?=?0.02 Bq/kg). The only determined anthropogenic nuclide was ¹³⁷Cs, arising from the fallout of the Southern Hemisphere nuclear weapon tests. Three of the observed differences in the depth distributions can be described by the dispersion-convection model. A correlation between the natural nuclide activities and the Mössbauer relative fractions was found, whereas no correlation was found between the ¹³⁷Cs profile and the relative fraction of Fe₃O₄ or with other iron species.     

Determination of terrestrial gamma, 238U, 232Th and 40K in soil along fracture zones

²³⁸U, ²³²Th and ⁴⁰K concentrations in 72 soil samples from two major fault systems (North and East Anatolian Active Fault Sytems) in Turkey have been studied. However, terrestrial gamma radiation dose originated by natural radionuclides in soil was measured and compared with other measurements in literature for different countries. This extensive survey regarding U, Th and K radionuclide and terrestrial gamma dose measurement was carried out by means of NaI(TI) gamma spectroscopic system and a dose rate meter, respectively. The mean concentration of ²³⁸U, ²³²Th and ⁴⁰K in soil samples in NAFS is higher than determined in EAFS. The measured and calculated mean gamma dose rates in two fault systems are found to be higher than 57 nGyh⁻¹.     

Identification and inventory of TENORM sources in Slovenia

The paper addresses identification of industries and activities handling NORM and inventory of TENORM in Slovenia. The identification is based on survey of historical information available, results published in scientific papers, research reports made by research institutions within Slovenia, as well as original research aimed at obtaining more detailed picture of the areas investigated. For this purpose, gamma dose-rate measurements were performed on site, sampled TENORM/NORM materials were measured by high-resolution gamma spectrometry for determination of ²¹⁰Pb, ²³⁸U, ²³²Th, ²²⁸Th and ²²⁶Ra. Waste water and ground water samples were analysed for ²³⁸U, ²²⁶Ra and ²¹⁰Pb using RNAA, LSC and beta proportional counting. The inventory of the investigated sites is presented, giving the information on amounts of the deposited wastes, specific activities of the natural radionuclides and geographical distribution of the inventories in Slovenia.     

Isotope shift and hyperfine structure of the highly excited atomic uranium

The laser induced fluorescence method using atomic beam combined with Doppler-free two-photon absorption technique was applied for the measurement of isotope shifts and hyperfine structures of atomic uranium including ²³⁴U, ²³⁵U, ²³⁶U and ²³⁸U isotopes. The isotope shifts between ²³⁸U-²³⁴U, ²³⁸U-²³⁵U, ²³⁸U-²³⁶U, and the hyperfine structure of ²³⁵U were obtained in the high lying odd levels around 4 eV. Received 3 December 2001 / Received in final form 4 July 2002 Published online 29 October 2002 RID="a" ID="a"e-mail: oba@analchem.tokai.jaeri.go.jp     

Fission of 232Th, 238U and 235U induced by negative muons

The absolute yields of prompt and delayed fission induced by negative muons in ²³²Th, ²³⁸U and ²³⁵U have been measured. The delayed fission yields are much lower than could be predicted from Γ_n/Γ_f systematics for 15–20 MeV nuclear excitation. The systematics of prompt fission yields are compared with recently obtained photofission data. It is suggested that prompt fission can be used for investigating the channel structure of the fission barrier.     

Symmetric and asymmetric yields in the photofission of232Th,235U,238U and239Pu

Measurements are presented for the mass and energy distributions of fragments from the photofission of²³²Th,²³⁵U,²³⁸U and²³⁹Pu. The experiments were performed for bremsstrahlung endpoint energies between 15 and 55 MeV, using silicon surface barrier detectors. The results are discussed with respect to the competition between the symmetric and asymmetric fission modes.     

Mean energies of prompt fission neutrons in the neutron-induced fission of <Superscript>235</Superscript>U at primary energies in the range <Emphasis Type="Italic">E</Emphasis><Subscript>n</Subscript> < 20 MeV

The spectra of neutrons accompanying the induced fission of ²³⁵U target nuclei are described theoretically. It is confirmed that a third neutron source must be introduced in order to reproduce the shape of experimental distributions at high energies of primary neutrons (previously, a third source was used in describing the spectra of neutrons emitted in ²³²Th and ²³⁸U fission). On the basis of experimental results and their analysis, the mean energy of fission neutrons is estimated as a function of the bombarding-neutron energy up to E _n = 20 MeV.     

Identification and inventory of tenorm sources in Slovenia

The paper addresses identification of industries and activities handling NORM and inventory of TENORM in Slovenia. The identification is based on survey of historical information available, results published in scientific papers, research reports made by research institutions within Slovenia, as well as original research aimed at obtaining more detailed picture of the areas investigated. For this purpose, gamma dose-rate measurements were performed on site, sampled TENORM/NORM materials were measured by high-resolution gamma spectrometry for determination of ²¹⁰Pb, ²³⁸U, ²³²Th, ²²⁸Th and ²²⁶Ra. Waste water and ground water samples were analysed for ²³⁸U, ²²⁶Ra and ²¹⁰Pb using RNAA, LSC and beta proportional counting. The inventory of the investigated sites is presented, giving the information on amounts of the deposited wastes, specific activities of the natural radionuclides and geographical distribution of the inventories in Slovenia.     

Radioactivity concentrations in topsoil samples from the Thrace region of Turkey and assessment of radiological hazard

The activity concentrations of gamma emitting radionuclides were measured in surface soil samples from the Thrace region. ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs activities and physico-chemical parameters of the soil samples were determined in samples collected from 73 sampling stations. Radionuclide concentrations measured were compared with those found in the samples from other locations of Turkey and from different countries. The average activity concentrations of ²³²Th, ²³⁸U, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were found to be 24.71 ± 8.79, 22.30 ± 7.93, 32.09±12.44, 509.00±160.05, 32.74±29.24 Bq kg^?1, respectively. The mean value of the annual effective dose equivalent from the outdoor terrestrial gamma radiation was calculated as 57.2 μ Sv.     

Results of radiation level study in some territories of Mongolia

The outdoor terrestrial gamma-ray background in the urban environment of provincial centers and several cities of Mongolia was studied in order to assess the absorbed gamma dose rates in the open air and determine the activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in soil samples collected from selected locations. The text was submitted by the authors in English.     

The importance of U-series disequilibrium of sediments in luminescence dating: A case study at the Roc de Marsal Cave (Dordogne,France)

A multidisciplinary study of the Roc de Marsal Cave gave us the opportunity to re-examine the known problem posed by U-series disequilibria in sediments in the field of palaeodosimetric dating. Apart from burnt flints and heated limestones, the material being dated, THAT IS our principal concern here, is made of burnt sediment samples collected from a reddish layer that forms the very base of the Roc de Marsal Mousterian sequence (Couche B). U-series disequilibria of long life nuclides in sediments were observed: as a general trend, the activity of ²³⁸U is greater than that of ²²⁶Ra. Important discrepancies in age determination can occur according to the origin of the disequilibrium and its kinetics. To characterise these ancient modifications of radioactivity and constrain the range of possible variations of annual doses, a statistical study of ²³⁸U, ²²⁶Ra and ²³²Th activities, measured by gamma spectrometry, was carried out. It shows that the sediment was mainly enriched in mobile uranium. This conclusion is in accordance with the results of complementary measurements of ²³⁰Th and ²³⁴U performed by alpha spectrometry. On the kinetics side, two models of time-variation of U and daughter concentrations are compared, taking experimental data into account. A detailed presentation of the methodology and the method of calculation of dose rates, and particularly time-averaged dose rates in such a situation, is given.