Consideration on intake of uranium through smoking

Uranium in Japanese tobacco leaves and in Japanese human hair was determined by the fission track method. It was found that the uranium content in smokers' hair was higher than that in non-smokers' one and a part of uranium was lost from tobacco leaves by ashing at 500–700 °C. These two results suggest that uranium would be inhaled through smoking.     

Microanalysis of uranium in Antarctica soil samples using fission track method

Soil samples collected at the Indian Antarctic station Maitree, situated at the Schirmachar Oasis and belonging to the East Antarctic charnockite provinces have been analysed to determine trace uranium concentrations. The fission track technique using Makrofol-KG as the track detector was used for the analyses. Finely powdered samples and pellets were irradiated with thermal neutrons from a nuclear reactor. Uranium concentrations were obtained from the tracks of the detector. Uranium concentrations were found to vary from 0.036 to 0.364 ppm in the samples investigated. The low levels of uranium indicate the absence of human intervention with the lithosphere in this region.     

Trace element analysis of uranium of soil and plant samples using fission track registration technique

The fission track registration technique using Melinex-0 as the detector has been applied to estimate uranium concentration in soil and plant samples collected from different parts of this region of India. The soil samples were powdered and plant samples were ashed to form pellets which were then irradiated with thermal neutrons. Uranium was found to vary from 0.023 to 0.430 ppm in soil samples and 0.026 to 0.216 ppm in plant (Mesophyte group) samples. Fission track technique provides simple, inexpensive, reliable and sensitive method and has high potentiality for uranium analyses in plants and agricultural crops and getting information about underlying ore and mineral deposits.     

Track etching characteristics of polyester track detector and its application to uranium estimation in seawater samples

Garware Polyester Film, an indigenously available material has been evaluated systematically as a nuclear track detector for the detection of fission fragments. The relative fission track detection efficiency of this film was found to be (86.0±4.0)%. The bulk etch rate, determined by the gravimetric method, was found to be 0.75±0.05 μm/h. The track etch rate was determined as 15.0±1.5 μm/h. This detector was employed for the estimation of uranium in seawater samples and the results obtained were compared with the results obtained by using the commonly used Lexan detector. Uranium fractions after chemical separation from seawater samples were also analyzed by alpha-spectrometry and neutron activation analysis techniques and the results were compared with that obtained by the fission track method. Fission track method has the advantage, as it does not require any chemical separation. The indigenously available polyester film (polyethylene terphthalate) appears to be a good substitute of Lexan as nuclear track detector.     

Determination of uranium concentration in domestic water samples by fission track method

The sensitive and simple fission track detection technique using a dry method with Melinex-0 plastic track detector has been applied for the determination of uranium concentration in samples of domestic water supply plants collected from different states of India, namely West Bengal, Uttar Pradesh, Rajasthan, Punjab and Delhi. Our analyses show that uranium concentration of water samples collected from different types of domestic water supply plants vary from 0.6±0.02 to 19.2±0.6 g/l. The present investigations may be useful from the point of view of radiation hygiene.     

Trace quantities of uranium in some Indian chewing tobaccos as determined by fission track analysis

The sandwiched pellet technique using Makrofol-E plastic track detectors has been employed to determine trace quantities of uranium in nine brands of flavored chewing tobaccos consumed by the Indian population. In this technique the nuclear reaction,²³⁵U(n,f), is used for the quantitative estimation of uranium. The maximum value of uranium (1.88 ppm) has been found in raw tobacco leaves (Surti), while the minimum (0.13 ppm) in Tulsi (Double Zero brand). Other seven brands showed intermediate values of U-contents which are also reported in this paper. These values are compared with the U-contents reported in the literature for other forms of tobaccos.     

Determination of uranium in powdered quartz at ppb level by fission track method

Summary The demand for powdered quartz with low alpha —radioactivity has been increasing in the field of manufacturing semiconductor memory device packages. In this work, the determination of uranium in powdered high-purity quartz samples was studied using a simplified fission track procedure in which 0.5 g each of sample and a fission track detector (synthetic quartz glass plate, uranium impurity 0.04 ppb) were loaded in a polyethylene capsule and irradiated with a thermal neutron flux of 10¹⁷ cm^–2. An easy procedure was also employed for chemical etching of fission tracks. All measurements of uranium concentration in the samples were made on a relative basis by comparing the unknown track densities to that measured for NBS glass SRM 617. The reliability was established for the present determination of uranium down to 0.1 ppb. The concentrations of uranium in powdered quartz samples studied in this work were in a range from 7.9 down to 0.12 ppb.

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Uranbestimmung in Quarzpulver im ppb-Bereich mit Hilfe der Kernspurmethode

Zusammenfassung Da im Bereich der Halbleiterindustrie eine steigende Nachfrage nach Quarzpulver mit niedriger Alpha-Aktivität besteht, wurde die Uranbestimmung in hochreinem Quarzpulver mit Hilfe einer vereinfachten Kernspurmethode untersucht, bei der jeweils etwa 0,5 g der Probe und des Kernspurdetektors (synthetisches Quarzglasplättchen mit etwa 0,04 ppb U) in eine Polyethylenkapsel gegeben und mit einem thermischen Neutronenfluß von etwa 10¹⁷ cm^–2 bestrahlt wurden. Ein einfaches Verfahren zum chemischen Ätzen der Spuren wurde angewendet. Alle Messungen der Urankonzentration wurden relativ durchgeführt durch Vergleich der unbekannten Spurdichten mit denen von Standardglas NBS SRM 617. Die Zuverlässigkeit des Verfahrens wurde bis herab zu etwa 0,1 ppb U geprüft. Die in den untersuchten Proben gefundenen Urankonzentrationen lagen im Bereich von 7,9 bis 0,12 ppb.

     

Determination of uranium concentration in water samples by the fission track registration technique

The fission track registration technique using Makrofol KG as detector and the wet method was developed for the determination of microgram amounts of uranium in water samples. This method allows the determination of uranium concentrations within the interval of 8.0 to 0.4 μg. U/l, the overall ranging from 3.3% to 29.0%. Results obtained for water samples from several sources in the State of São Paulo, Brasil, are reported.     

Nuclear analytical techniques for quantification of uranium for its recovery from seawater

Nuclear analytical techniques namely fission track technique using solid state nuclear track detector (SSNTD) and instrumental neutron activation analysis (INAA) have been standardized and applied for quantification of low uranium concentrations in liquid samples such as feed, elute and brine and solid sorbent samples respectively. The quantification of uranium is required for its recovery study from seawater, which is one of the potential sources of uranium. The uranium concentration of a liquid sample obtained by SSNTD method was compared with the other well established conventional techniques like ICP-MS, ICP-AES, adsorptive stripping voltametry and alpha spectrometry. INAA was applied for uranium concentration determination in the radiation grafted polyamidoxime sorbent samples.     

Measurement of uranium in human teeth and kidney stones with the fission track technique

The measurement of uranium in human teeth and kidney stones has been carried out by using the fission track activation technique. In this determination 2759 and 2205 absolute counts of tracks /for standard: 6940 and 1556/ for teeth samples and 1689 tracks /for standard: 1446/ for kidney stone samples have been made, respectively. The results obtained by this technique are the following: X_tooth/1/=/0.227±0.006/ ppm, X_tooth/2/=/0.143±0.007/ ppm and X_kidney=/0.568±0.020/ ppm. The experimental method is described and the results discussed.     

Determination of rare earth elements in phosphorites by neutron activation analysis

Fourty three phosphorite rocks from Western Iraq were analyzed for eleven REE as well as uranium by NAA using IRT Reactor with a neutron flux of 2.3·10¹³ n·cm^–2·s^–1. The gamma activity from each sample was counted with a Ge(Li) and well-type HPGe, each detector connected to an on-line computer. Uranium fission products and different reaction interferences were assessed and allowed for. The results were also checked against international reference materials.     

Uranium concentration in blood samples of Southern Iraqi leukemia patients using CR-39 track detector

The simple and effective technique of fission track etch has been applied to determine trace concentration of uranium in human blood samples taken from two groups of male and female participants: leukemia patients and healthy subjects group. The blood samples of leukemia patients and healthy subjects were collected from three key southern governorates namely, Basrah, Muthanna and Dhi-Qar. These governorates were the centers of intensive military activities during the 1991 and 2003 Gulf wars, and the discarded weapons are still lying around in these regions. CR-39 track detector was used for registration of induced fission tracks. The results show that the highest recorded uranium concentration in the blood samples of leukemia patients was 4.71 ppb (female, 45 years old, from Basrah) and the minimum concentration was 1.91 ppb (male, 3 years old, from Muthanna). For healthy group, the maximum uranium concentration was 2.15 ppb (female, 55 years old, from Basrah) and the minimum concentration was 0.86 ppb (male, 5 years old, from Dhi-Qar). It has been found that the uranium concentrations in human blood samples of leukemia patients are higher than those of the healthy group. These uranium concentrations in the leukemia patients group were significantly different (P < 0.001) from those in the healthy group.     

Fission track–secondary ion mass spectrometry as a tool for detecting the isotopic signature of individual uranium containing particles

A fission track technique was used as a sample preparation method for subsequent isotope abundance ratio analysis of individual uranium containing particles with secondary ion mass spectrometry (SIMS) to measure the particles with higher enriched uranium efficiently. A polycarbonate film containing particles was irradiated with thermal neutrons and etched with 6 M NaOH solution. Each uranium containing particle was then identified by observing fission tracks created and a portion of the film having a uranium containing particle was cut out and put onto a glassy carbon planchet. The polycarbonate film, which gave the increases of background signals on the uranium mass region in SIMS analysis, was removed by plasma ashing with 200 W for 20 min. In the analysis of swipe samples having particles containing natural (NBL CRM 950a) or low enriched uranium (NBL CRM U100) with the fission track–SIMS method, uranium isotope abundance ratios were successfully determined. This method was then applied to the analysis of a real inspection swipe sample taken at a nuclear facility. As a consequence, the range of ²³⁵U/²³⁸U isotope abundance ratio between 0.0276 and 0.0438 was obtained, which was higher than that measured by SIMS without using a fission track technique (0.0225 and 0.0341). This indicates that the fission track–SIMS method is a powerful tool to identify the particle with higher enriched uranium in environmental samples efficiently.     

Investigation of uranium and thorium concentrations in the fluorite beds of Anatolia by using solid state nuclear track detectors

Uranium and thorium concentrations of fluorite samples taken from the main fluorite beds of Anatolia (Turkey) have been determined by fission fragment radiography using solid state nuclear track detectors (SSNTDs). The fissionable elements concentration of the fluorite samples were found to be 10^–4–10^–7 g/g. The Th/U ratio, obtained for all the fluorite samples, is found to be characteristic for the location of the samples. Some correlations between the concentration of Th and those of lanthanites and concentration of U and that of Mo or Zr are observed.     

Liquid-liquid extraction and spectrophotometric determination of uranium with n-phenyl-3-styrylacrylohydroxamic acid (PSAHA)

A rapid, selective and sensitive liquid-liquid extraction and spectrophotometric method for the separation and microgram determination of uranium using PSAHA is described. Uranium is extracted with PSAHA into chloroform at pH 6.0–6.8. The U-PSAHA chelate is orange red in color having maximum absorbance at 410 nm and molar absorptivity 1.2·10⁴l·mol^–1·cm^–1. The system obeys Beer's Law in the range of 1.2 to 22.00 ppm of uranium. The uranium is determined in sea water and rock samples.     

Direct determination of thorium in uranium oxide by X-ray fluorescence

Summary Thorium in uranium is determined directly at trace levels by an XRF method. Uranium oxide samples are put in the form of double layer pellets and analysed by using Philips PW-1220 X-ray spectrometer. The typical value of the precision of the method at 200 ppm level is ±10% and estimation range is 50–1000 ppm of thorium in uranium.

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Direkte Bestimmung von Thorium in Uranoxid durch Röntgenfluorescenz-Spektrometrie

Zusammenfassung Mit Hilfe der beschriebenen Methode kann Th in Spurenkonzentrationen direkt bestimmt werden. Die Uranoxidproben werden als Doppelschicht-Tabletten eingesetzt und mit Hilfe eines Philips PW-1220 Röntgenspektrometers analysiert. Die Genauigkeit im Bereich von 200 ppm beträgt ±10%. Der Anwendungsbereich liegt bei 50–1000 ppm.

     

Uranium concentration measurements in human blood for some governorates in Iraq using CR-39 track detector

The sensitive and simple technique of fission track etch has been applied to determine trace concentration of uranium in blood samples for occupational and non-occupational workers, male and female, using CR-39 track detector that is employed for registration of induced fission tracks. The results show that the highest recorded uranium concentration in human blood of workers in the ministry of Science and Technology were 1.90 ppb (male, 36 years old, 12 years' work experience, and living in Basrah governorate) and minimum concentration 0.26 ppb (female, 40 years old, 10 years' work experience, and living in Baghdad), while for non-occupational worker, the maximum uranium concentration was 1.76 ppb (female, 63 years old, and living in Al-Muthana) and minimum concentration was 0.28 ppb (female, 20 years old, and living in Baghdad). It has also been found that the uranium concentration in human blood samples of workers in the ministry of Science and Technology are higher than those of non-occupational workers, and the uranium concentrations for female workers and for non-occupational workers were higher than those for male workers and non-occupational workers.     

A gas-jet system for the study of short-lived,light fission products

A selective method for the solvent extraction and spectrophotometric determination of uranium(VI) is described. Uranium can be extracted into chloroform at pH 6.0 with N-m-chlorophenyl-2-theno-hydroxamic acid (N-m-CPTHA) and determined by spectrophotometry using 1-(2-pyridylazo)-2-naphthol (PAN). The molar absorptivity is 1.50·10⁴ 1·mol^–1·cm^–1 at 560 nm. The system obeys Beer's law within the range 0.95–20.00 ppm of uranium. Alternatively, a back-extraction procedure was also developed in which uranium is back-extracted by nitric acid and estimated spectrophotometrically using Arsenazo III. The molar absorptivity is 2.0·10⁴ 1·mol^–1·cm^–1 at 665 nm. The parameters concerning the optimum conditions for the analytical method are discussed. The proposed method is applied precisely for the determination of uranium in rock and sea water samples.     

Separation and determination of uranium(VI) with calixarene hydroxamic acids

A new calixarene hydroxamic acid, 5,11,17,23-tetra-(N-p-chlorophenyl hydroxamate c-phenyl-25,26,27,28-tetrahydroxycalix[4]arene (CPCHA) was synthesized and used for the extraction and spectrophotometric determination of uranium(VI). The molar absorptivity of the uranium(VI)-CPCHA-thiocyanate complex was 9.9·10³ 1·mol^–1·cm^–1 at 436 nm. The system obeyed Beer's law in the range of 1.78–23.1 ppm of uranium. The uranium(VI)-hydroxamate-ethyl acetate complex was directly aspirated for graphite furnace atomic absorption spectrometry measurements (GFAAS) which increased the sensitivity by about a factor of fifty. Uranium was determined in various standard and environmental samples.     

Combined application of alpha-track and fission-track techniques for detection of plutonium particles in environmental samples prior to isotopic measurement using thermo-ionization mass spectrometry

The fission track technique is a sensitive detection method for particles which contain radio-nuclides like ²³⁵U or ²³⁹Pu. However, when the sample is a mixture of plutonium and uranium, discrimination between uranium particles and plutonium particles is difficult using this technique. In this study, we developed a method for detecting plutonium particles in a sample mixture of plutonium and uranium particles using alpha track and fission track techniques. The specific radioactivity (Bq/g) for alpha decay of plutonium is several orders of magnitude higher than that of uranium, indicating that the formation of the alpha track due to alpha decay of uranium can be disregarded under suitable conditions. While alpha tracks in addition to fission tracks were detected in a plutonium particle, only fission tracks were detected in a uranium particle, thereby making the alpha tracks an indicator for detecting particles containing plutonium. In addition, it was confirmed that there is a linear relationship between the numbers of alpha tracks produced by plutonium particles made of plutonium certified standard material and the ion intensities of the various plutonium isotopes measured by thermo-ionization mass spectrometry. Using this correlation, the accuracy in isotope ratios, signal intensity and measurement errors is presumable from the number of alpha tracks prior to the isotope ratio measurements by thermal ionization mass spectrometry. It is expected that this method will become an effective tool for plutonium particle analysis. The particles used in this study had sizes between 0.3 and 2.0 μm.