Table 1 Mean concentration of uranium-238 (238 U) and thorium-232 (232 Th) in soil samples collected, around various types of medicinal plants Full size table The results for uranium and thorium specific activities in different parts (roots, stems, leaves and seeds/or fruits) of studied medicinal plants are given in Tables 2 and 3, respectively.

Soil-to-plant transfer factor (TF) is one of the most important parameters to be used in transfer models for predicting the concentration of radionuclides in agricultural crops and for estimating dose impacts to man.

Thorium concentrations in coal fall within a similar 1–4 ppm range, compared to an average crustal abundance of approximately 10 ppm. Coals with more than 20 ppm thorium are extremely rare. During coal combustion most of the uranium, thorium, and their decay products are released from the original coal matrix and are distributed between the ...

A "critical" concentration of thorium in the extracellular space was found to be between 10 −7 and 10 −6 M; above this concentration, thorium hydrolyzes, becomes colloidal, and distributes primarily to organs of the reticuloendothelial system; below this concentration, thorium is distributed primarily to bone. The exposure levels in the ...

However, plants grown at the edge of impoundments of uranium tailings containing elevated levels of thorium had a plant/soil concentration ratio of about 3 (Ibrahim and …

An increase of Th content in plants may cause a decrease of concentration of such essential macro-nutrient as calcium and variations in concentrations of many trace elements.

At the Yellow river, China, thorium concentrations in water in the vicinity of the Baotou plant are generally below the detection limit of 0.002 μg/L, but thorium was found to be increased in leachates with about 0.064 μg/L, and it is strongly contaminated with chemicals used for processing at Baotou, which affect fish population and people ...

A review of the available data on thorium concentrations in plants and related foodstuffs is presented. It is shown that the concentration of 232 Th in plants in regions with normal background radiation varies from 0.5 × 10 -4 to 22.8 Bq/kg, while it reaches 0.058-80.0 Bq/kg (dry weight) in regions with elevated environmental thorium concentrations.

In the present work, we study the linearity assumption for isotopes of natural uranium (234 U and 238 U), thorium (232 Th, 230 Th and 228 Th) and radium (226 Ra), as well as the dependence of TF values on the stable element concentrations in substrates and plants, specifically from granitic and alluvial soils to pasture located in an area that ...

4. Conclusions. Wheat seedlings were treated with thorium nitrate solution at two stages of their growth: (1) during germination in water medium, and (2) during growth in soil, after germination. Both treatments resulted in an increase of Th concentration in roots and in seeds. The leaf Th content remained low.

The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 ... thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium nitrate at IPEN -CNEN/SP. The paper presents preliminary …

The stock solution of thorium (1.0 mmol L −1) was prepared with Th(NO 3) 4 ∙6H 2 O (analytical reagent) and further diluted to the required concentration for further use. 100 mg of CA membrane was suspended in 50 mL of thorium solution, followed by constant shaking in 130 rpm for 24 h at 303, 313 and 323 K, respectively.

Thus a coal power plant can conceptually fuel 13 thorium plants of its own power. From a different perspective, 1 pound of Th has the energy equivalent of 5,000 tons of coal. There are 31 pounds of Th in 5,000 tons of coal. ... It occurs in secular equilibrium in the decay chain of natural uranium at a concentration of 17 ppm.

The study assessed natural radioactivity in Rohtak and Jind districts, Haryana, India. Concentrations of radionuclides in soil and building materials were measured using gamma-ray spectroscopy. The "Canister Technique" was employed to estimate radon mass exhalation and surface exhalation rates. Results showed low radiation doses from soil …

not bioconcentrate in plants from soil. However, plants grown at the edge of impoundments of uranium tailings containing elevated levels of thorium had a plant/soil concentration ratio of about 3 (Ibrahim and Whicker 1988). The atmospheric mass concentration of thorium ranged from 0.2 to 1.0 ng/m 3, with a mean value of

Thorium is a naturally occurring, slightly radioactive element. It is widely distributed in nature with an average concentration of 10.5 ppm Th in the upper earth's crust. In general, thorium occurs in relatively small number in Th-enriched minerals: thorite, thorianite, monazite, bastnaesite, and thorogummite. However, the main world resources …

Addition of a small amount of thorium to the media resulted in a significant increase of thorium concentration both in roots and leaves of the wheat seedlings. The uptake of Th by roots depended of the media where the plants grew: it was more significant in water-grown plants. ... Among other radio-nuclides, limited information is available on ...

Download Citation | On Jan 26, 2024, S. V. Fesenko and others published Thorium Concentrations in Plants: A Review of World Data | Find, read and cite all the research …

Taking into account the relevant figures, the following remarks can be made: (1) 238U and z~ZI'h concentrations are either not detectable or very low; in the second case, they were found in the collection and separation plants; (2) 226Ra concentration is higher in oil extraction plant scales (800+3000 Bg/kg) than in other plants (300+400 Bg/kg ...

) = logm (CR,,b~c) - 1.12 x (lsoilPb -I'-0" 174) (3) where l~o~lpb is the logt0 of the required soil 2mPb concentration in Bq/g. Plant~soil concentration ratios of U. Th and Pb 271 RELATIONSHIP OF RESULTS TO BASIC PRINCIPLES The substantial variability of CR values and the lack of consistently reported ancillary data mean that few of the …

In all tested media, thorium accumulation in plants was after 7 days bigger at 0.5 mM Th than at the lower Th concentration (0.1 mM). The amount of thorium in roots increased in the presence of putrescine or in the absence of iron or phosphate ions, with the highest content in roots achieved in plants subjected to phosphate deficiency (267.1 ...

La, Ce, Nd, Sm, Eu, Tb, Yb and Lu were determined in needles of age class 5 from 6 individual Norway spruce trees and in their soils. Measurements were done by neutron activation analysis with a group separation of the REE. Concentrations in spruce needles are among the lowest values reported for plant leaves. Concentrations show …

This concentration is assumed to be the same as the Orissa Sands Complex in India. 13 Mt. Weld has high estimated costs due to the low grade of thorium in the rare earth separation plant feed (40% REO, 0.13–0.16% ThO2). While the Araxá deposit has a 0.10% grade of thorium in situ, the processing plan for the proposed mine does not …

Monazite is found in igneous and other rocks but the richest concentrations are in placer deposits, concentrated by wave and current action with other heavy minerals. ... In Norway, Thor Energy is developing and testing a thorium-bearing fuel for use in existing nuclear power plants. Fuel rods containing thorium additive (Th-Add) and also ...

In most cases main source of thorium for its trans-fer into plants is the soil [1]. Fallout of radionuclides from the atmosphere and subsequent surface contam-ination of plants are also of great importance and can significantly affect the thorium concentrations in veg-etation [2, 3]. Other sources of plant contamination, such as irrigation, may ...

Negative correlation was found between putrescine concentration and thorium accumulation. Nevertheless, the most important factor influencing the accumulation of thorium was the absence of phosphate ions in a hydroponic medium that caused more than 10-fold increase of thorium uptake in all plant parts.

uptake of uranium and thorium by plants, including relationships. between these radionuclides in soil and in plants and t emporal. changes of uranium and thorium concentrations in different plant ...

Natural thorium is present in trace quantities in virtually all rock, soil, water, plants and animals. Where higher concentrations occur in rock or sands, thorium may be mined and refined, producing waste products such as mill tailings. If not properly controlled, wind and water can introduce the tailings into the wider environment.

The effects of different hydroponic conditions (such as concentration of thorium (Th), pH, carbonate, phosphate, organic acids, and cations) on thorium uptake by Brassica juncea var. foliosa were evaluated. The results showed that acidic cultivation solutions enhanced thorium accumulation in the plants. Phosphate and carbonate …

The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal …