When consumed, this may expose people to radiation. For this reason, it is important to know the amounts of radionuclides in food and drinking water and, if necessary, control their distribution. Naturally occurring radioactive material, such as potassium-40, polonium-210, thorium-232 and uranium-238 can be found in food and drinking water.

According to their origins, radionuclides can be classified into primordial (natural) radionuclides and anthropogenic radionuclides. The main sources of naturally occurring primordial nuclides (radio‑potassium, radio‑uranium and radio‑thorium) are the Earth's crust and mantle, which were created before the formation of the Earth ( Povinec ...

Natural uranium is a silver-colored radioactive metal that contains three forms (isotopes) of uranium: uranium-234, uranium-235, and uranium-238. The amount of uranium-238 in natural uranium is more than 99 percent, but the uranium-234, present at 0.005 percent in natural uranium, accounts for half of the radioactivity. (2)

Included are radionuclides of lead, polonium, bismuth, radium, potassium, carbon, hydrogen, uranium, and thorium. Potassium-40 is the most prominent radionuclide in normal foods and human tissues. The dose to the total body from these internally deposited radionuclides has been estimated to be approximately 40 mrem year −1 for the United ...

Uranium and thorium decay series disequilibria in deep geothermal brines are a result of water–rock interaction processes. The migratory behavior of radionuclides provides valuable site-specific information and can therefore be an important tool for reservoir characterization and sustainable management of geothermal sites. In this …

The latter are known as primordial radionuclides and include 40 K (1.3 × 109 years) and the isotopes of uranium and thorium that give rise to various daughter nuclides including 226 Ra (1,600 years), 222 Rn (3.8 days), and 210 Pb (22.3 years) (Strebl et al. 2007). Artificial radionuclides have entered the human environment as a consequence …

The measured radionuclides and the distribution patterns for Uranium-238 (238 U), Thorium-232 (232 Th), and Potassium-40 (40 K) from 120 sampling points in the study area are shown in Table 1 ...

The biogeochemical behavior of a radionuclide in a given decay chain can be expected to vary with atomic number (that is, the element). For example, in the uranium decay …

It is well known that mining of uranium ore produces large amounts of tailings that contain high concentrations of uranium-series radionuclides. The effective dose rate produced by radionuclides that were released from ... To establish a secular equilibrium between the parent nuclides of uranium and thorium and their short-lived products, the ...

Radionuclide Basics: Thorium. Thorium (chemical symbol Th) is a naturally occurring radioactive metal found at trace levels in soil, rocks, water, plants and animals. Thorium is solid under normal conditions. There are natural and man-made forms of thorium, all of which are radioactive. In general, naturally occurring thorium exists as Th …

The primary purpose of this chapter is to review existing and proposed Environmental Protection Agency (EPA) guidances and regulations that apply to control of routine exposures of the public to naturally occurring radionuclides. As discussed in chapter 2, the naturally occurring radionuclides of primary concern in radiation protection of the public …

@article{osti_263097, title = {The distribution of uranium and thorium decay-series radionuclides in the environment - a review}, author = {Cowart, J B and Burnett, W C}, abstractNote = {Natural radioactivity has played an indispensable role in the development of the earth to the form and shape that we now observe. Energy from …

The input of thorium series radionuclides is of marginal significance, exhibiting only negligible fraction of the total activity related to 226 Ra and its progenies. It should be expected that during chemical operations with phosphorite ore, isotopes are preferentially separated according to their chemical properties.

Bismuth, thorium, uranium, and plutonium are primordial radionuclides because they have half-lives long enough to be still found on the Earth. Potassium-40 also belongs to primordial nuclides. When the Earth was formed, many radioactive elements were formed. After four billion years, all the shorter-lived isotopes have decayed.

29 Uranium, Thorium and Anthropogenic Radionuclides as Atmospheric Tracers 593. Monthly total (wet + dry) deposition samples (rain- water between 10 and 100 L) are evaporated to dry- ness in an evaporation dish, or in a glass flask in a rotary vacuum evaporator. Residue samples in the monthly deposition are weighed after being dried in …

Naturally occurring radionuclides of the uranium decay series (238 U) and thorium decay series (232 Th) and 40 K are the main contributors to the high levels of terrestrial radiation . There are a few regions in the world which are known to be high background natural radiation areas (HBNRAs) due to local geology and geochemical …

Uranium and thorium are long-lived radioactive elements found in all Earth material. Upon radioactive decay they form other radionuclides which are themselves …

The alpha sources for uranium, thorium, and polonium were covered with a thin film to prevent daughter recoil contamination of detectors (Inn et al. 2008). An alpha spectroscopy system (Mirion Technologies, Inc.), equipped with 72 Passivated Implanted Planar Silicon (PIPS) detectors, connected to an Apex-Alpha software system, was used …

The radionuclides of the uranium-238, thorium-232, and uranium-235 decay series are shown in Figures 1, 2, and 3, along with the major mode of radioactive decay for each. Radioactive decay occurs when an unstable (radioactive) isotope transforms to a more stable isotope, generally by emitting a subatomic particle such as an alpha or beta particle.

Monazite is an orthophosphate mineral which contains between 50–68 % REE, up to 20 % thorium and up to 0.5 % uranium and is therefore considered to be a naturally occurring radioactive material (NORM) [].The mineral is an important source of REE and countries including India, Brazil, Australia, USA, South Africa, Sri Lanka, …

Furthermore, gamma-emission, which originates from natural sources, is a result of primordial radionuclides, which are mainly Thorium-232 ( 232 Th) and …

For example, the decay chain that begins with Uranium-238 culminates in Lead-206, after forming intermediates such as Uranium-234, Thorium-230, Radium-226, and Radon-222. Also called the "decay series.". ... Some radionuclides have half-lives of mere seconds, ...

It can be seen that the transfer of uranium and thorium based on the available fraction was similar to that of radiocaesium and higher than that of other artificial radionuclides. The thorium ATF values were at the same level as 40 K and, for some species of mushroom, also as 137 Cs, and higher than 226 Ra. In the uranium case, the …

Reported uranium and thorium concentrations in oil field wastewater are very scarce. Typical concentrations of these radionuclides in produced water usually …

The possible isotopic pairs for possible determination by gamma-ray spectrometry and with relatively long half-lives are 226 Ra and 238 U as well as 210 Pb and 226 Ra in uranium chain, and 228 Th and 228 Ra radionuclides within the thorium series.

Thorium Series – Key Radionuclides. In most uranium deposits the contribution to radiation exposure from thorium is far less significant than that from uranium. …

The behavior of radionuclides of the uranium (U) and thorium (Th) decay series in terrestrial systems is of interest because of environmental effects of mining and disposal activities related to nuclear power plant fuels. The soft-plant relationships of U, Th, and polonium ...

Since 2017, natural radionuclides have been regulated in the Swiss Ordinance on drinking water and water for public baths and shower facilities (TBDV) . ... Uranium and thorium are separated with ALPHAEX/H 2 SO 4 extraction. Pu, Am and Cm are extracted with ALPHAEX/HNO 3. U and Th are separated by sequential extraction …

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

Radionuclide Basics: Thorium. Thorium (chemical symbol Th) is a naturally occurring radioactive metal found at trace levels in soil, rocks, water, plants and animals. Thorium is solid under normal conditions. There are natural and man-made forms of thorium, all of which are radioactive. In general, naturally occurring thorium exists as Th …

Naturally occurring radionuclides are also produced by cosmic radiation which permeates space, arising primarily from outside of our solar system and occurring in many forms, from high-speed heavy particles to high-energy photons and muons. ... Natural thorium and uranium decay chains. Half-lives and decay, d, days; h, hours; m, minutes; …

Among the relatively limited body of work on the removal of thorium from contaminated environments, confirmed thorium immobilization on acid-modified GAC surfaces, performed better at pH 2.8 when ...

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

Chapter 10 Uranium- and Thorium-Series Radionuclides in Marine Groundwaters. Pb/Pb in vent fluids have been used to constrain the residence time of the circulating Rn over ambient seawater. Temporal variability of the radon content has been used to gain insight into sub-sea floor processes. The serve as both important sources …

The behavior of radionuclides of the uranium (U) and thorium (Th) decay series in terrestrial systems is of interest because of environmental effects of mining and disposal activities related to nuclear power plant fuels. The soil-plant relationships of U, Th, and polonium (Pb), and some other daughter radionuclides, notably radium ({sup …

The uranium tailings contain a large amount of radium, besides other radionuclides like uranium, thorium, polonium and lead. The transport and fate of radionuclides in groundwater are assumed to follow the theoretical approach represented by the basic diffusion/dispersion — advection equation. Our algorithm uses the analytical …

Radium-226 is one of the decay products of uranium-238, which is widespread in most rocks and soils. When this radium decays it produces radon-222, an inert gas with a half-life of almost 4 days. (Radium-224 is a decay product of thorium, and it decays to radon-220, also known as thoron, … See more

Abstract. A review of publications is presented on the state of uranium, radium, and thorium in soils. It is shown that the properties of radionuclides in soils provide the diversity of the forms ...