Determination of uranium, thorium and potassium activity concentrations …
The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean acti … Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan Radiat Prot Dosimetry. …
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Automated flow systems for total and isotopic analysis of uranium …
Furthermore, in the fertilizer, uranium and thorium concentrations are generally approximately 150% of their original concentration in the phosphate rock. Radionuclides dispersed on agricultural land via the spreading of fertilizers are redistributed in the environment by means of soil erosion and surface water runoff. In the south of …
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Determination of uranium and thorium concentration and …
The elemental concentrations of uranium, thorium and potassium obtained from the three areas where soil samples were collected are summarized in Table 2. The measured arithmetic mean and stand deviation of elemental concentrations for U 238, T 232 h and K 40 in all the samples studied are 2.29 ± 0.95 ppm, 7.77 ± 3.98 ppm and …
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Value of potassium, uranium and thorium concentration
Download scientific diagram | Value of potassium, uranium and thorium concentration with Th/U ratio, Th/K ratio and the gamma ray in API obtained from the for- mations sample from publication ...
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Uranium, thorium and tungsten concentration measured in …
The studies carried out in the period 2002–2015 aimed, in particular, to verify if the concentrations of uranium, thorium and tungsten in soils of the firing range area have been enhanced by military training operations, causing a risk for the environment and the human health. Results seem to exclude this hypothesis; moreover it was ...
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A comparison of analytical methods for determining uranium and thorium
The activity concentrations of uranium and thorium isotopes in the separated sources were determined by alpha spectrometry with PIPS semiconductor detectors of 600 mm 2 active area, housed in Alpha Analyst model 7200-08. The radiotracers used for the determination of chemical yield in uranium and thorium …
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Uranium and thorium isotopic and concentration
Radionuclides (including those of uranium and thorium) are commonly used to quantify complex geochemical processes in aqueous environments. The estimation of mass transport fluxes for uranium (U) and thorium (Th) isotopes is plagued, however, by uncertainties predominantly driven by the inability to determine solute–particulate …
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Thorium, uranium and potassium in some sandstones
The average and nearly uniform values found in orthoquartzitic, clay-free sands were potassium (as metal) 0.64 ± 0.04 percent; thorium 1.7 ± 0.1 p. p. m .; and uranium 0.45 ± 0.05 p. p. m ., giving a Th/U ratio of 3.8 ± 0.8. The Th/U ratio found is very near to that of average igneous rocks and may represent an independent determination of ...
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Determination of uranium, thorium and potassium activity concentrations …
The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher.
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Tantalum, niobium, thorium and uranium concentrations …
Download Table | Tantalum, niobium, thorium and uranium concentrations (in mg/kg DW) in selected reference materials used in this work from publication: Simultaneous determination of tantalum ...
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Determination of uranium and thorium concentrations in …
@article{osti_5466319, title = {Determination of uranium and thorium concentrations in unprocessed soil samples}, author = {Lazo, E N and Roessler, G S and Berven, B A}, abstractNote = {An assay technique that directly determines the amount of 238U and 232Th in unprocessed, bulk soil samples has been developed. In this …
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Geoscience Wisconsin URANIUM AND THORIUM IN …
Uranium and thorium are present in trace amounts in almost all geolo gical materials as minor constituents in the lithosphere. Taylor (1964) cal culates that the average concentration of uranium in the earth crust amounts to 1.8 ppm (parts per million) and that of thorium 7.2 ppm. Uranium and thorium
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Thorium Concentrations in the Environment: A …
Thorium concentrations are usually rather low in surface waters, with the highest values being observed in regions with an elevated thorium content in the parent …
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Evidence and uncertainty for uranium and thorium …
The first, from ~0 to 1 Ga (or ~ -4.5 to −3.5 Ga from today), involved successive concentrations of uranium and thorium from their initial distribution into the …
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HPS 2018
The average concentration of uranium in the groundwater of the United States is about 0.07 Bq L-1. The US Environmental Protection Agency's (EPA) drinking-water standard …
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2 Natural Radioactivity and Radiation
Where uranium and thorium concentrations are high enough, rocks constitute ores to industrial societies. In the western United States, uranium ores have been extensively mined and milled to produce nuclear fuels. ... In the common rock types, the uranium concentrations range from 0.5 to 4.7 ppm, corresponding to activity concentrations for …
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Determination of uranium, thorium and potassium activity concentrations
Kim in 1995 reported the presence of radionuclide of thorium's and uranium series in limestone and also same traces concentration of thorium, uranium and potassium in black shale in some regions [4].
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Determination of uranium and thorium in complex samples …
Model samples contained the known concentrations of uranium and thorium. After preconcentration and separation, thorium and uranium were determined by spectrophotometry. Sample volume was 1.33 L for UTEVA resin and 1.04 L for TRU resin, while concentration of uranium and thorium was about 10 μg L −1. At the beginning …
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Uranium and thorium isotopic and concentration
We have developed techniques by sector-field inductively coupled plasma mass spectrometry (ICP-MS) for measuring the isotopic composition and concentration of uranium and thorium, focusing on the rare isotopes, 230 Th and 234 U. These isotopes have been widely used as tracers in earth sciences, e.g., chronology, paleoclimatology, …
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A critical review on the occurrence and distribution of the uranium
Naturally occurring radionuclides in groundwater resources can pose risks to human health due to both toxicity and radiation. For example, high concentrations of uranium in drinking water have been associated with nephrotoxic and other health effects (Zamora et al., 1998; Kurttio et al., 2002; WHO, 2017; Ma et al., 2020, Ma et al., …
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Amazon and Mississippi river concentrations of uranium, thorium…
Concentrations of uranium and thorium series isotopes were measured in two large samples of river water and associated sediment. From these data an oceanic residence time for uranium of 4 m.y. is calculated. The concentration of 232 Th in these rivers is an order of magnitude greater than in surface Atlantic waters.
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Abundances of Uranium and Thorium Elements in Earth …
The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid-Scintillator Antineutrino Detector (KamLAND). ... The crustal composition model used in Enomoto et al. has been updated by changing the U and Th concentrations in the upper continental crust by − 3.6% and …
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AGE DEPENDENCE OF NATURAL URANIUM AND THORIUM CONCENTRATIONS
The age dependence of the natural concentration of uranium and thorium in the skeleton was investigated using human vertebrae bone collected from two Canadian locations (Winnipeg, Manitoba, and Regina, Saskatchewan). The concentration of both radioelements in digested ashed bone samples was determined using sector-field …
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Challenging the thorium-immobility paradigm | Scientific …
In this study, we determined the solubility of Th dioxide (ThO 2) in aqueous solutions as a function of sulfate concentration from 0.05 to 0.5 m Na 2 SO 4 at temperatures between 175 and 250 °C ...
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THORIUM, URANIUM AND ZIRCONIUM CONCENTRATIONS …
The uranium concentrations ranged from 2.7 to 26.7 ppm and averaged 11.4 ppm. The thoriumto-uranium ratios ranged from 1.5 to 20.9, with an average value of 5.1. Zirconium determinations on some of the bauxites gave values ranging from 0.02 to 0.65% zirconium, and averaging 0.09% zirconium. The thorium, uranium, and zirconium contents of the ...
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High resolution analysis of uranium and thorium concentration …
We have mapped U (238 U) and Th (232 Th) elemental concentrations as well as U-series isotope distributions in a Neanderthal tooth from the Middle Palaeolithic site of Payre using laser ablation ICP-MS.The U-concentrations in an enamel section varied between 1 and 1500. ppb.. The U-concentration maps show that U-migration through …
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Exploring the use of thorium isotope compositions and concentrations …
This interlaboratory study measured thorium concentrations and isotope compositions in uranium ore concentrates from different geographical locations to examine whether thorium impurities may be useful forensic signatures for uranium ore concentrates found out of regulatory control. Measured 230Th/232Th in fifteen uranium ore …
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Determination of thorium, uranium and potassium …
A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of ...
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Concentrating on thorium
The second was to accurately determine the concentration of thorium, which is usually present at very low concentrations. This is hardly surprising seeing as uranium-234 is a minor uranium isotope, accounting for just 0.0055% of raw uranium, and its half-life is so long, meaning only a fraction will have decayed to thorium-230. Sample …
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Naturally-Occurring Radioactive Materials (NORM)
Concentrations of actual radionuclides may or may not have been increased; if they have, the term technologically-enhanced NORM (TENORM) may be used. Long-lived radioactive elements such as uranium, thorium and potassium and any of their decay products, such as radium and radon are … See more
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