Uranium Series Radionuclides Research Articles

Quantifying of highly radioactive and radiotoxic polonium-210 intake from cannabis (Cannabis sativa L.): impacts of different smoking and vaporization techniques.

This study investigates the radiation dose that humans receive from naturally occurring uranium-series radionuclides, with a focus on alpha-emitting polonium-210 (210Po), which has a half-life of 138.4days. Polonium is efficiently absorbed by living organisms and is estimated to contribute approximately 7% of the total effective dose from ingested natural internal radiation. The primary source of atmospheric 210Po is the decay of radon-222 (222Rn), which precipitates onto land and water surfaces, including crops. In Cannabis sativa, 210Po accumulates primarily through direct deposition on leaf surfaces and from fertilizers, particularly phosphate fertilizers. This study examined 10 samples of dried hemp (Cannabis sativa L.) legally available in Poland, assessing 210Po concentrations through radiochemical analysis. Various consumption methods were analyzed, including smoking with a glass pipe, a water pipe (bong), a cigarette (joint or spliff), and vaporization. The desorption of 210Po during combustion and vaporization was measured, revealing significant differences based on the method used. Results showed that smoking with a glass pipe resulted in the highest desorption of 210Po (approximately 80%), while water pipe and blunt smoking exhibited lower desorption rates (around 40%). The efficiency of 210Po adsorption in filters varied, with water filters showing about 8% absorption and cellulose filters about 20%. Vaporization results indicated that the desorption of 210Po increased with temperature. These findings underscore the importance of considering the method of consumption when calculating the radiation dose from 210Po, as the differences can significantly impact the accuracy of dose assessments. The study highlights the need for further research to optimize safety guidelines for cannabis consumption in relation to radioactive contaminants.

A comparative study of the elevated radioactivity in beach placer deposits of Bangladesh.

Beach sediments are mineral deposits formed through weathering and erosion of either igneous or metamorphic rocks. Among the rock constituent minerals are some natural radionuclides that contribute to ionizing radiation exposure on Earth. Kolatoli and Kuakata are the two major beaches with heavy mineral deposits and important tourist sites in Bangladesh. Natural radioactivity in Kolatoli and Kuakata beach sand deposits along the southern coast of Bangladesh was assessed and compared to identify the sources, causes, and possible environmental impact. Result shows most of the radionuclides have higher activity concentrations than the background level, and the activity varies with the sample locations. The dominant radionuclides were found to be the radionuclides of thorium series i.e. Th-232 and Ra-228 followed by uranium series and K-40. The radioactivity in Kolatoli beach sands was observed to be much higher than Kuakata beach due to the presence of a higher content of heavy minerals i.e. illmenite, rutile, zircon, garnet and monazite. Furthermore, monazite and zircon are the two radioactive minerals that are considered to be the main contributors to the radioactivity in Kolatoli beach sand. These minerals are dominated by the activity of thorium series radionuclides i.e. Th-232 and Ra-228 surpass the activity of all other radionuclides such as U-238, U-234, Th-230, Ra-226, Po-210, and K-40. However, major contribution of radioactivity in Kuakata beach sand comes from uranium series radionuclides such as U-238, U-234, Ra-226, and Po-210. Beach morphology, sedimentological, and geochemical evolution of those minerals might be important areas of further study for the radioactivity monitoring activity in those areas.

The environmental consequences of rapid urbanization in central Florida reconstructed with high resolution 241Am and 210Pb dating in lake sediments

Throughout the 20th century, Florida was one of the fastest growing states in the US, putting unique environmental stress on the region. Accurately dated lake sediments can provide invaluable records of environmental change that extend beyond monitoring records. Here, we analyze profiles of americium-241 (241Am), cesium-137 (137Cs), lead (Pb), zinc (Zn), and uranium-series radionuclides in Lake Bonny in Lakeland, Florida. The 241Am peak is sharp in the sediment profile, while the 137Cs peak is broader and spread evenly across two layers. The measured 137Cs inventory of ~448Bq/m2 is less than half of the expected inventory from atmospheric deposition (accounting for decay since deposition), indicating significant losses. The reliability of 137Cs as a chronological tool can be complicated in environments with low quantities of 2:1 clays and low available potassium (K), characteristic of Florida and the U.S. southeast. Using a piecewise constant rate of supply 210Pb model verified by 241Am, we reconstruct sedimentation and chemical change in this lake. Highest sedimentation rates in the lake occur during decades of peak population growth in the mid-20th century. Uranium (U) and radium-226 (226Ra) inputs to the lake reach a maximum in the 1960s, consistent with expansion of local phosphate mines and elevated groundwater pumping during that time in response to drought conditions. Total Pb in the sedimentary record captures the rise and fall of the use of leaded gasoline, but Zn inputs to the lake remain nearly two orders of magnitude above background levels in the last decade. Our high-resolution chronology of the lake reveals regional impacts on water and lake quality in central Florida during a period of rapid population growth.

Accounting for Overcounting Induced by 222Rn Contamination in 14C Measurements Performed with Liquid Scintillation Counting

Abstract This research paper introduces a methodology for estimating overcounting resulting from uranium series radionuclides, with a specific focus on 222Rn contamination. The method is demonstrated using the Quantulus 1220TM spectrometer. Exponential fitting is employed for the calculations, utilizing a custom algorithm developed in MATLAB® R2022b. The proposed method allows for the determination of the sample count rate correction, F14C and radiocarbon age without the need for additional chemical treatment or specialized electronics during liquid scintillation counting (LSC) measurements with the Quantulus 1220TM spectrometer. However, the method does have certain limitations. It requires a significant number of cycles and extended measurement time per cycle, but it can be applied to samples with significant 222Rn contamination that require rapid 14C analysis.

Does exposure to weathered coal ash with an enhanced content of uranium-series radionuclides affect flora? Changes in the physiological indicators of five referent plant species

Coal ash deposited in open landfills is a potential source of environmental pollutants due to the contained toxic element content. The weathered coal ash used in this study additionally contains enhanced activity concentrations of 238U series radionuclides. This study aimed to determine the physiological effects of enhanced ionizing radiation and toxic elements on five plant species (smilo grass, sticky fleabane, blackberry, mastic and pine tree) inhabiting the coal ash disposal site. Among the potentially toxic measured elements, contents of Sb, As and especially V significantly exceeded their respective levels at the control site, as well as the content of 238U and its progenies. Significant changes in photosynthetic pigments were recorded following chronic exposure to the plants growing on the coal ash site. Different responses were also observed in the plant species regarding the activity of catalase and glutathione-S-transferase (GST). The level of lipid peroxidation markedly increased in plants from the disposal site, except in blackberry, wherein GST activity was the strongest, indicating an important role of that enzyme in the adaptation to coal ash pollutants. The results of this study suggest that the modulation of the studied biochemical parameters in plants growing on coal ash is primarily species-dependent.

Evaluation of natural radionuclides distribution in beach sands of Cox’s bazar sea beach, Bangladesh, using multivariate statistical technique

ABSTRACT The distribution of natural series radionuclides 226Ra, 232Th and non-series 40K in the heavy mineral-rich beach sands of highly touristic areas of Cox’s Bazar sea beach has been studied. The study is made to evaluate the gamma radiation exposure to individuals with an aim to establish reference data for the presence of naturally occurring radionuclides. The present study reports the probable first attempt of detail and systematic work in the study areas for estimation of activity concentration in the recent beach sand samples. Radiometric analysis was performed using gamma ray spectroscopy system based on HPGe detector. The mean activity levels of 226Ra, 232Th and 40K in Laboni beach sands were ranged from 255.69±64.57, 336.83±93.96 and 1785.91±89.60 Bq kg-1, respectively. While in Kolatoli beach sands, the respective values were 166.42±35.99, 157.35±35.90 and 1894.42±74.07Bq kg-1, respectively. The mean values of 226Ra and 232Th concentrations in the investigated beach sands were estimated to be very much higher than the corresponding world average values and comparable to those found in high background radiation areas in the world. The heavy minerals seem to control the activity concentrations of 226Ra and 232Th in sand samples, showing some variances based on uranium and thorium bearing minerals. Various radiation health hazard indicators were found to be extremely higher when compared to the recommended values. Hence, heavy mineral-rich sands may pose a significant radiological health risk to the people. The descriptive statistics indicating the radionuclides of 226Ra, 232Th and 40K are uniformly and symmetrically distributed in the Cox’s bazar beach sand. Multivariate statistical analysis showing the radioactivity and estimated radiological parameters are strongly positively correlated with 226Ra and 232Th, while weakly correlated with 40K, signifying that radiological risk is mainly associated and controlled by the radioactivity levels of uranium and thorium series radionuclides.

ОЦІНКА БАГАТОРІЧНИХ ПРОСТОРОВО-ЧАСОВИХ ЗМІН ХІМІЧНОГО СКЛАДУ ПІДЗЕМНИХ ВОД У ЗОНІ ВПЛИВУ КОЛИШНЬОГО УРАН-ПЕРЕРОБНОГО ПІДПРИЄМСТВА ВО «ПРИДНІПРОВСЬКИЙ ХІМІЧНИЙ ЗАВОД»

This study provides an analysis of data from long-term (2005-2021) observations of the chemical composition of groundwater in the impact zone of the former uranium ore processing enterprise (Production Union Prydniprovskyi Chemical Plant (PU “PChP”) in the city of Kamianske, in particular, areas of near-surface tailings of uranium ore processed residues (“Zapadnoe”, “Central Yar” and others). All tailings on the site of the former PU “PChP” were built without installation of anti-permeable barriers, and therefore under the influence of atmospheric precipitation, the water, formed in the tailings body, highly contaminated of uranium series radionuclides and residues of chemical reagents, can penetrate to the groundwater aquifers, with which they spread beyond the limits of their technological localization in tailings. In addition, the entire territory of the former industrial site of mining and chemical production “PChP” is a complex of former enterprises, septic tanks, production waste holding sites, warehouses of chemical reagents and residues of former production, which are also sources of man-made pollution of the territory and influence on chronic pollution of groundwater. Therefore, environmental monitoring programs in the impact zone of tailings impoundments included not only monitoring of indicators of the content of uranium series radionuclides in elements of the natural environment, but also studying of the chemical composition of waters. The analysis of observation data during the period from 2005 to 2021 was carried out in order to assess the extent of the spread of polluted waters beyond the limits of the location of the tailings ponds, to identify major macroions in the composition of groundwater as indicators for assessing the spread of the contamination plume beyond the boundaries of the tailings ponds, as well as to identify patterns of formation the groundwater quality within the site under the influence of man-made and natural factors. It is shown that the mineralization of groundwater, as well as its chemical composition, significantly changed as the sampling site moved away from the tailings. Changes in the chemical composition of water and the dominant content of the major macroions at different distances from the tailing’s ponds made it possible to determine the difference in the characteristics of the influence of infiltration waters from the source of the tailing’s ponds and scattered sources of pollution within the boundaries of the PChP site along the groundwater flow line. The main factors of uncertainty in the estimations of the formation of groundwater chemistry in the zone of the industrial complex are shown, which must be taken into account for the development of the network of monitoring observations.

Radionuclides and stable elements in vegetation in Australian arid environments: Concentration ratios and seasonal variation

Data on the uptake of elements and radionuclides by flora from soils in arid environments are underrepresented in international databases, especially when comparing across seasons. This study improved the understanding on the uptake of natural uranium-series radionuclides, as well as more than 30 elements, in a range of Australian native flora species that are internationally representative of an arid/semi-arid zone (e.g. Acacia, Astrebla, Atriplex, and Dodonea). Results indicate that the soil-to-plant uptake ratios were generally higher when compared with international data for grasses and shrubs from more temperate environments. The majority of the elemental concentrations in grasses were higher in winter than in summer and the opposite trend was found in shrubs, which suggests that the season of collection potentially introduces variability in the reported concentration ratios. The data also suggest that grasses, being dominant and widespread species in arid zones, may be effective as a reference organism to ensure comparative assessment across sites of interest. The results of this study will improve the confidence of environmental assessments in arid zones.

222Rn Exhalation Flux Rate and 226Ra in the Soils of a Copper-Mineralised Area.

Uranium-series radionuclides exist in trace quantities in all soils and rocks on earth in variable concentrations. Among these, 222Rn gas exhaled by the soil of a geological location is the main contributor to the environmental radioactivity. A 222Rn exhalation flux study was carried out in the heavily mineralised area of the Singhbhum Copper Belt of Jharkhand, India. A significant seasonal variation in the soil gas exhalation was observed, which is attributable to the seasonal atmospheric parameters of the study area. The average 222Rn exhalation flux from the soil was estimated to be in the range of 4.5-$20.1\ \mathrm{Bq}\ {\mathrm{m}}^{-2}\ {\mathrm{s}}^{-1}$ with a mean of $10.1\pm 3.9\ \mathrm{mBq}\ {\mathrm{m}}^{-2}\ {\mathrm{s}}^{-1}$ and geometric mean (GM) of $9.5\ \mathrm{mBq}\ {\mathrm{m}}^{-2}\ {\mathrm{s}}^{-1}$. Also, 20 soil samples collected from the study area were analysed by the emanometric method, which estimated the 226Ra specific activity in the soils in the range of 9-$63\ \mathrm{Bq}\ \mathrm{k}{\mathrm{g}}^{-1}$ and a mean value of $39\pm 16\ \mathrm{Bq}\ \mathrm{k}{\mathrm{g}}^{-1}$.

Simultaneous Determination of Gross Alpha/Beta Activities in Groundwater for Ingestion Effective Dose and its Associated Public Health Risk Prevention

This paper presents information on the gross alpha and gross beta activity concentrations of two hundred twenty-six groundwater samples collected by gas flow proportional counters in southern Vietnam. The gross alpha results in the water samples ranged from 0.024 to 0.748 Bq L−1 with a mean of 0.183 ± 0.034 Bq L−1, and the gross beta results in the water samples ranged from 0.027–0.632 Bq L−1 with a mean of 0.152 ± 0.015 Bq L−1. The values obtained in this work were compared with those previously published for various regions or countries. Next, untreated and treated groundwater samples were analyzed to assess their influences on the treatment process. The results showed that there were differences in the minimum detection concentrations and the mean activity values between the untreated and treated groundwater samples (The p-value of the mean comparison tests is significant with p < 0.05). In both sample groups, there was a strong positive correlation of the gross alpha versus the gross beta results (r > 0.6). This means that among the radionuclides, the major sources of beta radiation are uranium and thorium decay series radionuclides. Finally, the annual effective dose for adults (>17 years) was calculated based on the assumption that major radionuclides have the highest effective dose conversion factors. In general, the results for Pb-210, Ra-226, and Ra-228 were observed to be lower than the recommended reference values established by the World Health Organization and the International Atomic Energy Agency, except for the value of Po-210.

Disequilibrium of uranium series radionuclides in soil and plants of South India

Soil and plants of South India were analysed using standard methods for equilibrium state between radionuclides 226Ra, 210Pb, and 210Po of uranium series. A disequilibrium state was observed, with mean 210Pb/226Ra, 210Po/226Ra, and 210Po/210Pb as 21.71, 5.52, and 0.40; 10.01, 4.21, and 0.43; and 30.86, 9.34, and 0.35 in Coastal Karnataka, Malnad Karnataka, and Malnad Kerala, respectively. 210Po/210Pb in soil was 0.29, 0.30, and 0.49 respectively, for the three regions. Unsupported 210Pb and 210Po might have caused the observed disequilibrium state. The investigation helps to monitor radionuclide distribution and dynamics in soil and plants of the study area.

Study of equilibrium status among uranium and thorium series radionuclides in soil samples from Visakhapatnam, India

Surface soil samples from coastal region of Visakhapatnam were analyzed for uranium series and thorium series radionuclides by high-resolution gamma-ray spectrometry. Isotopic ratios of 226Ra/238U and 224Ra/232Th were calculated to investigate the radioactive equilibrium status in the samples. 226Ra/238U and 224Ra/232Th ratios were found to vary from 0.80–1.40 to 0.94–1.40 with mean values of 1.05 and 0.99, respectively. Results showed a prevalent radioactive equilibrium for both uranium and thorium series radionuclides in the surface soil of the study area.

Disequilibrium of Naturally Occurring Radioactive Materials (NORM) in Drill Cuttings from a Horizontal Drilling Operation

Naturally occurring radioactive materials (NORM) in solid waste or “drill cuttings” produced from unconventional drilling for natural gas extraction wells potentially pose environmental contamination risks; however, the composition and mobility of NORM in these solid wastes are poorly understood. In this study, the composition of NORM, including uranium, thorium, radium, lead, and polonium isotopes, was evaluated in three samples of drill cuttings extracted from a well drilled into the Marcellus Shale formation. Leachability of NORM in drill cuttings was characterized by leaching the solid waste with dilute acetic acid at four different pH values. The uranium-series radionuclides in cuttings and leachate samples displayed isotopic disequilibrium, suggesting some environmental mobility of radionuclides in these shale formations. Our results indicate that isotopic analysis of uranium-series radionuclides is needed for a more complete understanding of the potential environmental contamination risks associate...

Influence of soil structure on the “Fv approach” applied to 238U and 226Ra

The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides 238U and 226Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides 238U and 226Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively.

Radiological and elemental analysis of soils from Hunza in Central Karakoram using gamma-ray spectrometry and k 0-instrumental neutron activation analysis

This study is aimed at establishing the current contents of elements and radionuclides in soil of eight towns of Hunza, Central Karakoram at an average altitude of 2300 m above sea level. Gamma-ray spectrometry measured three natural and one anthropogenic radionuclides and k 0-INAA determined 31 elements. The air absorbed dose rate in air varied from 90 to 105 nGy h−1 with an average of 95 ± 7 nGy h−1.The measured data was compared with similar data of the world. A comparison of 226Ra and 238U showed that uranium series radionuclides were in equilibrium in Hunza soil.

An investigation into the upward transport of uranium-series radionuclides in soils and uptake by plants

The upward migration of radionuclides in the 238U decay series in soils and their uptake by plants is of interest in various contexts, including the geological disposal of radioactive waste and the remediation of former sites of uranium mining and milling. In order to investigate the likely patterns of behaviour of 238U-series radionuclides being transported upward through the soil column, a detailed soil–plant model originally developed for studying the behaviour of 79Se in soil–plant systems has been adapted to make it applicable to the 238U series. By undertaking a reference case simulation and a series of sensitivity studies, it has been found that a wide variety of behaviour can be exhibited by radionuclides in the 238U decay chain in soils, even when the source term is limited to being a constant flux of either 238U or 226Ra. Hydrological conditions are a primary factor, both in respect of the overall advective flow deeper in the soil, which controls the rate of upward migration, and in the influence of seasonally changing flow directions closer to the soil surface, which can result in the accumulation of radionuclides at specific depths irrespective of changes in sorption between the oxic and anoxic regions of the soil. However, such changes in sorption can also be significant in controlling the degree of accumulation that occurs. This importance of seasonally varying factors in controlling radionuclide transport in soils even in very long-term simulations is a strong argument against the use of annually averaged parameters in long-term assessment models.With a water table that was simulated to fluctuate seasonally from a substantial depth in soil to the surface soil layer, the timing of such variations in relation to the period of plant growth was found to have a major impact on the degree of uptake of radionuclides by plant roots.In long-term safety assessment studies it has sometimes been the practice to model the transport of 226Ra in soil, but to assume that both 210Pb and 210Po can be treated as being present in secular equilibrium with the 226Ra. This simplification is not always appropriate. Where geochemical conditions are such that the 226Ra migrates upward in the soil column faster than 210Pb and 210Po, disequilibrium is not a significant issue, as the 226Ra supports 210Pb and 210Po at concentrations somewhat below those estimated on the basis of assumed secular equilibrium. However, for low, but realistic, values of the distribution coefficients for 210Pb and 210Po and high, but realistic, distribution coefficients for 226Ra, the 210Pb and 210Po can reach the surface soil in high concentrations that are not locally supported by 226Ra. This means that models based on the assumption of secular equilibrium should not be employed without a careful consideration of the hydrological and hydrochemical situation of interest.

Radioactivity in Iberian Rivers with Uranium Mining Activities in their Catchment Areas

Rivers flowing through the uranium mining region of Portugal, such as the Mondego andZêzererivers,receive drainage from areas of old uranium mines. The international River Águeda, a tributary to River Douro, has also important uranium mining and milling facilities in its catchment basin in Spain. In order to assess the radioactive contamination of these river basinsresulting from uranium mining waste, uranium series radionuclides were measured in water, suspended particulate matter, and riverbed sediments.Results showed that significant radioactivity enhancement took place in sections of these rivers.This contamination persisted long time after environmental remediation implemented at some mine sites and cessation of mine discharges. The persistent risk of waste leaching and dam failure requires continued monitoring of radioactivity levels in these rivers.

Modelling the behaviour of uranium-series radionuclides in soils and plants taking into account seasonal variations in soil hydrology

In a previous paper, a mathematical model for the behaviour of 79Se in soils and plants was described. Subsequently, a review has been published relating to the behaviour of 238U-series radionuclides in soils and plants. Here, we bring together those two strands of work to describe a new mathematical model of the behaviour of 238U-series radionuclides entering soils in solution and their uptake by plants. Initial studies with the model that are reported here demonstrate that it is a powerful tool for exploring the behaviour of this decay chain or subcomponents of it in soil-plant systems under different hydrological regimes. In particular, it permits studies of the degree to which secular equilibrium assumptions are appropriate when modelling this decay chain. Further studies will be undertaken and reported separately examining sensitivities of model results to input parameter values and also applying the model to sites contaminated with 238U-series radionuclides.

Uranium series radionuclides in surface waters from the Shu river (Kazakhstan)

The concentrations of (238)U, (234)U, (226)Ra, (210)Po and (210)Pb have been determined in surface waters collected along the course of the Shu River, lying on the border between Kazakhstan and Kyrgyzstan. In the study area, the river runs through some of the largest uranium deposits worldwide, which were actively exploited during the nuclear weapons and nuclear energy programmes of the former Soviet Union. The data show an increasing trend in uranium concentrations downstream the river from the city of Tokmak to the city of Shu, with good correlation between total uranium concentrations and total dissolved solids. Data on uranium isotopes disequilibrium show the presence of technogenic uranium inputs into the Shu River downstream from the city of Karasu, evidenced by a decrease in the measured (234)U/(238)U isotopic ratio from 1.63 in uncontaminated sites to 1.29 in sites affected by past mining activities.

Effect of laser irradiation of nanoparticles in aqueous uranium salt solutions on nuclide activity

This paper presents an experimental study of the effect of laser irradiation of aqueous uranyl chloride solutions containing gold nanoparticles on the activity of the uranium series radionuclides 234Th, 234mPa, and 235U. The solutions were exposed to femtosecond Ti:sapphire laser pulses and to the second or third harmonic of a Nd:YAG laser (150-ps pulses) at a peak intensity in the medium of ∼1012 W cm-2. The activities of the radionuclides in the irradiated solutions were shown to differ markedly from their equilibrium values. The sign of the deviation depends on the laser wavelength. The measured activity deviations can be interpreted as evidence that laser exposure of nanoparticles accelerates the alpha and beta decays of the radionuclides. The observed effects are accounted for in terms of a mechanism that involves resonant enhancement of optical waves by metallic nanoparticles.