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 …

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 …

Uranium, thorium, and rare earth elements (REEs) are important strategic elements in today's world with a range of applications in high and green technology and power generation. ... Thorium concentrations in the lithosphere range from 8 to 12 μg g −1. It is a weakly radioactive metal, similar to uranium, and occurs naturally in various ...

2.1. Stalagmite thorium and Dust Column Mass Density (DCMD) correlation. Here, we demonstrate the presence of a relationship between Dust Column Mass Density (DCMD), a measure of mineral dust in the atmosphere, and mean stalagmite 232 Th concentrations over the recent past. DCMD data were obtained from the Modern-Era …

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

The concentration of uranium and thorium in bottom and flyash can be up to ten times greater than for the burnt coal, while other radionuclides such as Pb-210 and K-40 can concentrate to an even greater degree in the flyash. Some 99% of flyash is typically retained in a modern power station (90% in some older ones).

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 …

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 …

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.

In natural waters, the above processes resulted in concentrations as high as 69.2, 2.5, and 24.8 mg L −1 for U, Th, and REE, respectively, while in soils and …

The average crustal abundance of uranium is 2.76 weight parts per million (wppm), higher than the average concentrations of such economically …

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 ...

Thorium abundance is reported in the range 35 ppb–60 ppm, the uranium abundance from 14.9 ppb to 95 ppm and the Th/U concentration ratio from 0.1 to 10. Table 1. Variability of thorium and uranium abundances and ratios. (literature: from recent to early publications). [Th] (ppm) [U] (ppm) [Th/U] (−) Sample ( a number of samples).

This critical review presents the key factors that control the occurrence of natural elements from the uranium- and thorium-decay series, also known as naturally …

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 ...

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 ...

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 …

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 …

The thorium and uranium concentrations decrease while the mineral concentrations increase with depth in the deposit. This observation can be explained by a continuous growth of the phillipsite within the deposits. The varying concentrations of uranium and thorium in phillipsite, fish teeth and clay minerals from given levels of the …

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 ...

The authors measured uranium and thorium in urine of 500 US residents to establish reference range concentrations using a magnetic-sector inductively coupled argon plasma mass spectrometer (ICP-MS). They found uranium at detectable concentrations in 96.6% of the urine specimens and thorium in 39.6% of the specimens.

Hence, the distribution of radioactive elements such as Potassium (K), Thorium (Th) and Uranium (U) concentration in soil and rocks relate to the differences in lithology of common rocks ...

@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 …

In-situ assessment of natural terrestrial-radioactivity from Uranium-238 (238U), Thorium-232 (232Th) and Potassium-40 (40K) in coastal urban-environment …

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., …

177 ICP-MS Determination of Uranium and Thorium Concentrations and 235U/238U Isotope Ratios at Trace and Ultratrace Levels in Urine *J.S. Beckera, M. Burowb, S.F. Boulygaa, C. Pickhardta, R ...

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].

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 …

Table 2.1 and Table 2.2 also show typical concentrations in various environmental media. Radionuclides Induced in Earth's Atmosphere by Cosmic Rays . Table 2.2. Nonchain …