CHAPTER 5. POTENTIAL FOR HUMAN EXPOSURE
The atmospheric mass concentration of thorium ranged from 0.2 to 1.0 ng/m 3, with a mean value of ... The average population-weighted concentrations of 232 Th 230and Th in United States community water supplies derived both from surface and groundwater were <0.01 and <0.04 pCi/L, respectively (Cothern 1987; Cothern et al. 1986). ...Web
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Nature, Sources, Resources, and Production of Thorium
Geochemistry of thorium and thorium minerals. Thorium is widely distributed in nature with an average concentration of 10.5 ppm Th in the upper earth's crust, while the middle crust has an average of 6.5 …Web
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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 …Web
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Radionuclide Basics: Thorium | US EPA
Thorium occurs naturally in the earth's crust at an average lithospheric concentration of 8–12 μg/g (ppm). Of the naturally produced thorium isotopes, only 232Th, 230Th, and …Web
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Thorium distribution on the lunar surface observed by Chang
In terms of the average thorium content of each rock type and the four levels of Th contents (suggested in the "Results" section), KREEP basalt possesses very high Th abundance, alkali suite is typical of high or very high thorium concentration, and the other three types of lithologies—magnesian suite, ferroan anorthosite and mare basalt ...Web
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Thorium distribution in the crust: Outcrop and grain-scale …
Geoaccumulation indexes and enrichment factors did not reveal significant alterations in topsoil thorium concentration. The average concentration was 13.6 ± …Web
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Toxicological Profile for Thorium
Thorium Isotopic Concentration in Three Occupational Cases and the General Population of Grand Junction, Colorado (pCi/kg) ..... 99 7-1. Regulations and Guidelines Applicable to Thorium..... 113 . THORIUM 1 . CHAPTER 1. RELEVANCE TO PUBLIC HEALTH ...Web
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Using yttrium as an indicator to estimate total rare earth element
This study demonstrated using yttrium (Y) as an indicator to estimate the total rare earth element and Y contents (REY) in coal-associated samples and to facilitate selection of samples with high REY assays in a fast and inexpensive manner. More than 10 anthracite-associated samples were collected from each of three Pennsylvanian sites …Web
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Assessment of concentration of radium, thorium, and
The radium equivalent activity was found to have an average value of 186.8 Bq/kg, with a maximum of 231.5 Bq/kg and a minimum of 18.2 Bq/kg. The Indian average radium, thorium, and potassium concentration values as per the UNSCEAR 2000 report are 29 Bq/kg, 64 Bq/kg and 400 Bq/kg.Web
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Baseline thorium concentration and isotope ratios in topsoil of
Establishment of thorium baseline concentration in topsoil from Zacatecas state, Mexico. Although the accepted estimation of the average crustal thorium concentration is around 10.5 mg kg −1, the debate about the thorium distribution in the crust is currently open (McLennan, 2001; Rudnick and Gao, 2014; Williams et al., 2018).Web
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A comparison of analytical methods for determining uranium and thorium
At higher fluoride concentrations thorium precipitates as the fluoride, ... of the samples. The other acid digestions gave 59% yield compared to pure nitric acid. On average, the thorium digestion yield of other acids was 37% compared to pure nitric acid and the range was very wide, from 0% to 78%. The corresponding values for uranium …Web
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a. Thorium -potassium cross-plot to identify clay type of Rudies
RHP estimated from the concentrations of radioactive elements (A R) vary from 0.13 to 2.1 mW/m 3, with an average 0.71 mW/m 3 and a standard deviation of 0.38 mW/m 3. 50% of these RHP values fall ...Web
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Thorium Concentrations in the Environment: A Review of the …
The average thorium concentration in the Earth's crust is about 5.6 ppm (or 5.6 mg/kg). The concentra-tion of thorium is higher in the upper part of the Earth's crust, reaching 10.5 ppm, while its average concentration in the lower layers is 1.2 ppm [1–3]. There are 31 known radioactive thorium isotopes;Web
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Determination of the elemental concentration of uranium and thorium …
The highest values of uranium and thorium concentrations (4053 ± 428 ppm and 33578 ± 873 ppm, respectively) were observed in xenotime and monazite; whereas the lowest value was 5.48 ± 0.86 ppm of uranium recorded in waste (sand) and 9 ± 0.32 ppm of thorium for waste (sand) and pyrite.Web
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(PDF) Uranium and Thorium Resources of Estonia
Thorium concentrations ar e analyzed in less than 100 drill cores, where the average varies between less than 1 and 17 ppm. As there are very few measurements of Th concentrations in westernWeb
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Ultra-effective modified clinoptilolite adsorbent for selective thorium
where Ce is the equilibrium concentration of thorium ions in the solution (mg/L), qe is the amount of adsorbed thorium ions per PZ unit weight at equilibrium state (mg/g), K L is the Langmuir ...Web
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Evaluation of naturally occurring radioactive materials (NORM) in …
The average of the activity concentrations of uranium, thorium, potassium, while radio in soil samples were 11,7 BqKg −1, 33,0 BqKg −1, 424,5 BqKg −1, and 15,59 BqKg −1, respectively, and the activity concentrations of radon in the water were 139.3 and 750.4 Bqm −3, which are within the values allowed by the World Health Organization. TheWeb
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UNITED STATES DEPARTMENT OF THE INTERIOR …
composition. The mean thorium content, 20.3 ppn, and mean Th/D, 3.19, are normal. The most uraniferous and fertile rocks are the peraluminous two- mica granitic suite, although not all two-mica plutons are enriched in uranium. The muscovite-bearing suite has mean uranium content of 22.3 ppm, mean thorium content of 22.8 ppm, and mean Th/U of 2.82.Web
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Thorium, uranium and potassium in some sandstones
Discussion" OF RESULTS The data in Table 1 are particularly noteworthy for the rather uniform and low thorium and uranium concentrations found in the ordinary orthoquartzites studied. Excluding the three placer-sand samples, the average thorium is 1-7 0-1 p.p.m., the average uranium is 0-45 0-05 p.p.m., and the average Th/U ratio is 3-8 0-8.Web
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Thorium
Element Thorium (Th), Group 20, Atomic Number 90, f-block, Mass 232.038. ... the value given is the abundance weighted average. Isotopes Atoms of the same element with different numbers of neutrons. ... reserve distribution, production concentration, substitutability, recycling rate and political stability scores. Crustal abundance (ppm) The ...Web
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Uranium content in granite rocks | Download Table
The granitic rocks which occur in most of the study area contain uranium in the range of 10.2-116 ppm with an average of 35 ppm and thorium between 25.5 and 60.7 ppm with an average of 50 ppm [13Web
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Occurrence of uranium, thorium and rare earth elements in the
Thorium concentrations in the lithosphere range from 8 to 12 μg g −1. It is a weakly radioactive ... bottom and fly ashes from five coal-fired power plants were found to be enriched in REEs and yttrium, with average concentrations of 658 ± 296 mg kg −1 and some elements reaching levels as high as 1257 mg kg −1 (Li C et al., 2019 ...Web
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Estimation of activity concentrations of radionuclides and
The mean concentrations of 226 Ra and 40 K in this study are far lower than the international reference standards, while the average value of 232 Th is higher than the international recommended ...Web
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Baseline thorium concentration and isotope ratios in topsoil of
The average concentration was 13.6 ± 7.6 mg kg −1, which is consistent with the estimated average concentration in the earth crust and is then proposed as average basal concentration for this region. A slight disequilibrium has been found between the natural isotopes of thorium due to the semi-arid nature of the areas and climatic factors.Web
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Thorium (Th)
Thorium is a chemical element with the atomic number 90 in the periodic table. The average concentration of this substance in the upper crust of Earth amounts to 10.5 ppm, while thorium concentration in the middle layer (the mantle) is around 6.5 ppm. The core (lowest layer) of the Earth's crust contains 1.2 ppm on average.Web
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Thorium deposits of the United States-energy resources
Thorium as a potential source fuel for energy generation has gained new attention in the United States, including consideration in the U.S. Congress (Branan, 2008).Web
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CHAPTER 5. POTENTIAL FOR HUMAN EXPOSURE
Thorium occurs naturally in the earth's crust at an average lithospheric concentration of 8–12 μg/g (ppm). The typical concentration range of naturally-occurring thorium in soil …Web
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The Determination of Radon/Thoron Exhalation Rate in an …
Sudden changes in concentration were observed, although no correlation with atmospheric pressure was found. The concentrations of radium (226 Ra) and thorium (228 Th) measured in samples collected from surrounding rock body were at average levels for the Earth's crust—about 12 Bq·kg −1 of 226 Ra and 13 Bq·kg −1 of 228 Th.Web
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Thorium distribution in the crust: Outcrop and grain-scale …
The average concentration was 13.6 ± 7.6 mg kg −1, which is consistent with the estimated average concentration in the earth crust and is then proposed as average basal concentration for this region. A slight disequilibrium has been found between the natural isotopes of thorium due to the semi-arid nature of the areas and climatic factors.Web
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A Study of Natural Radioactivity Levels and Radon/Thoron …
On average K 2 O values are less than K air activity concentration, ... showed the highest equivalent thorium concentration (16.22 mg kg −1) and thoron exhalation rate (2138 Bq m −2 h −1), respectively. The summary of soil geochemistry for grouped soil associations is expressed in Table 5. ...Web
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