Concentrations Of Uranium Isotopes Research Articles

Radiation protection for Gabes phosphate area residents: Assessing natural radioactivity in soil and potable water samples

Phosphate mining activities are recognized to be one of various industrial processes generating enhanced Naturally Occurring Radioactive Materials (NORM) by introducing natural radionuclides into the surrounding soils and water bodies, posing a risk to human health.This study was carried out to assess the level of natural radionuclides in soils and potable waters collected from the phosphate area of Gabes city, located in southeastern Tunisia, and to evaluate radiation protection measures by estimating radiological health hazard parameters. Gamma spectrometry system employing an HPGe detector was used in this study to assess 40K, 232Th and 226Ra activity concentration in soils. The average values were found to be 163.7, 14.5, and 7.7 Bq kg−1, respectively, which were lower than worldwide average values. The radiological hazard parameters assessed in this study were radium equivalent activity (Ra-eq), external hazard index (Hex), external gamma absorbed rate (GDR), external annual effective dose (Deff) and excess lifetime cancer risk (ELCR). The calculated average values of the above-mentioned parameters were of 41 Bq kg−1, 0.1, 20.2 nGy h−1, 24.8 μSv y−1 and 8.7 × 10−5 all of which were found to be below their permissible standards.For potable water samples, the activity concentrations of radium were analyzed using an HPGe detector and those of uranium were determined by alpha spectrometry. The average activity concentrations of uranium and radium isotopes in underground water samples were found to be higher than those obtained in tap water samples. For both types of water, the average values for all radionuclides were found to be below their respective reference limits.The annual ingestion effective doses were also estimated in this study. The estimated average values for infant and children for underground water samples were higher than the permissible limit of 100 μSv y−1 set by WHO. The 226Ra was the main contributor to the effective doses for different age categories, followed by 228Ra.

Evaluation of natural radioactivity and assessment of dose increase due to the use of fertilizers produced in Poland

AbstractSome types of fertilizers may contain various amounts of natural radionuclides like 238U, 232Th, 226Ra, 40K (Kuzmanoviæ et al. in J Radioanal Nucl Chem 331(12):5825–5834, 2022. 10.1007/s10967-022-08646-x; H Hamamo et al. in J Radioanal Nucl Chem 194(2): 331–336, 1995. 10.1007/BF02038431; M García-León et al. in J Radioanal Nucl Chem 197(1): 173–184, 1995. 10.1007/BF02040229). In this study 16 samples of commercially available fertilizers produced in Poland were selected for preliminary radiological evaluation. The samples were measured by means of low background gamma spectrometry. The results showed high concentrations of 40K in potassium and multinutrient fertilizers (2.3–13.8 kBq kg−1), and relatively high concentrations of uranium and radium isotopes in phosphate fertilizers. The obtained results allowed to calculate radium equivalent activity, absorbed dose rate increase and increase in annual effective dose equivalent.

Environmental evaluation of radioactivity levels and associated radiation hazards in groundwater around the WIPP site

Groundwater may contain radioactive substances which can be dangerous to human health. Concentrations of natural radionuclides polonium (Po), thorium (Th), uranium (U), and radium (Ra) isotopes were measured in groundwater samples collected from different locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, New Mexico. The average values of gross activity concentrations of 210Po, 228Th, 238U, 234U, 226Ra and 228 Ra isotopes were determined to be 1.62 Bq L-1 in shallow groundwater and 5.88 Bq L-1 in deep groundwater, respectively. The total radioactivity in deep groundwater was higher than that in shallow groundwater, and most of the radioactivity in the water is from 226Ra. Furthermore, the effective doses for ingestion of natural radionuclides were about 0.333 mSv y−1 for shallow groundwater and about 1.338 mSv y−1 for deep groundwater samples, which are higher than the World Health Organization (WHO, 2017) guideline level (0.1 mSv y−1) for drinking water. Ra dominated the total ingestion dose, contributing 93.06 % and 75.40 % of the total effective doses to the deep and shallow groundwater, respectively. The ingrowth and decay of natural radionuclides suggested that 228Ra/226Ra ratio can be a useful indicator of the source of radioactive contamination. The radioactivity data obtained from the investigated groundwater samples can be used to establish a baseline for radioactivity levels in groundwater around the WIPP site.

Isotopic profiling of natural uranium mined from northern Nigeria for nuclear forensic application

Four mined samples of natural uranium from northern Nigeria were studied through inductively coupled plasma mass spectrometry, at the Environmental Analytical Chemistry Laboratory, University of the Witwatersrand, Johannesburg. The samples were characterised for lead, thorium and uranium isotopic concentrations, isotopic ratios and age. The objective was to obtain nuclear forensic fingerprints as baseline data to add to the Nigerian National Nuclear Forensic Library. Results showed significant variation in the isotopic concentrations of lead, thorium and uranium across the mines. Isotopic ratios of 238U/235U, 235U/238U and 234U/238U across the sample of 137.881±0.007, 7.253×10-03±2.05×10-04 and 5.540×10-05±4.08×10-07 were found to be consistent with the natural values. The age of natural uranium is comparable to the age of earth. Uranium, lead, and thorium isotopic concentrations and ratios, as well as the age of the samples characterised, provide an isotopic profile that can be used for nuclear forensic application. Significance: Given the abundant deposits of natural uranium in Africa and the consequent potential for nuclear insecurity, determining the isotopic profiles and signatures of natural uranium is important for application in nuclear forensics. Isotopic concentrations of 232Th, 238U, 235U and 234U from the respective sampling sites differed significantly, thereby providing characteristic isotopic profiles.

Radioecological studies of the main naturally occurring radionuclides in the area of Gela Phosphate Industry (Italy) through radioanalytical separation and measurement techniques

Radioecological studies have been carried out in area of Gela Phosphate Industry. As a part of the project, some achievements have been described in the paper, including: (1) determination of the activity concentrations of 210Po, 210Pb, uranium, and radium isotopes in phosphogypsum, phosphoric acid, soil, and marine sediment, (2) inventory estimation of the NORM in the residual product and by-product, and (3) the radioecological investigation and evaluation on the NORM contamination in the sea area of Gela. The obtained data showed that the 210Po, 210Pb, uranium, and radium isotope contamination due to discharge of phosphogypsum from 1960s to 1990s is not observable through sediment analyses.

Uranium isotopes of aeolian dust deposited in northern Tibetan Plateau glaciers: Implications for tracing aeolian dust provenance

Asian dust comprises a large portion of the northern hemisphere atmospheric dust load, thereby exerting substantial influence on the Earth's climate, global biogeochemistry and hydrological cycle through accelerated snow and ice melt. Dust deposited on alpine glaciers encodes information on broad scale atmospheric-environmental processes. The (234U/238U) values of dust fine particulates can reflect the comminuting time and intermediate processes; thus, it provides a new method for the provenance of aeolian dust in the glacial snowpack/cryoconite. Here we present results from a comprehensive survey of uranium isotopic concentrations in dust collected from cryoconites on the glaciers of the northern Tibetan Plateau (TP). These results indicate significant spatial heterogeneity in the (234U/238U) values associated with snowpack/cryoconite dust over a broad range of glaciers in the northern TP. The values of the (234U/238U) ratio in the glaciers of western Qilian Mountains (Qiyi Glacier, Shiyi Glacier, Laohugou Glacier No.12) were the highest, followed by the Tanggula (Dunkemadi Glacier) and Kunlun Mountains (Yuzhufeng Glacier), whereas these values were the lowest in the eastern Qilian Mountains (Jingyangling Snowpack, Dabanshan Snowpack, Lenglongling Glacier). By including the analysis of Sr-Nd isotopic compositions, we find the spatial isotopic distribution reflects a combination of local dust, which is associated with short comminuting times, and dust transported over long ranges. Meteorological data indicate that the dust production in the west and north TP, Alxa arid lands and Gobi Deserts, may have a significant impact on the TP glaciers. Moreover, U-Sr-Nd isotopic composition and end-member mixing models (EMMA) were used in our study to find out the relative contribution of distinct Asian dust sources to the dust budget in the TP glaciers. The results reveal that snowpack/cryoconite dust is derived from both local sources (low comminution signatures) as well as other dust sources in the Asian region. Our study demonstrates the potential of U isotope composition as a dust tracing method. In particular, by investigating this composition on dust collected from glacier snowpack and cryoconite holes, we arrive at a map of the distribution characteristics of (234U/238U) values in different regions of the TP. Our study is the first to deploy uranium comminution age for Tibetan dust source tracing, and the results are important to elucidate the multiple origins and dynamics of dust in the Tibetan Plateau.

Uranium isotopes in food and effect on health of Southern Kazakhstan citizens

ABSTRACT Natural uranium isotopes were determined in food products of the Kyzylorda region in Kazakhstan. This region is characterised by the influence of the uranium industry, as up to 15% of the world uranium reserves are concentrated in this part of Kazakhstan and the adjacent territory of Kyrgyzstan. The food products most consumed by locals were selected for this survey. Special attention was paid to the analysis of edible and non-edible parts of food products and the assessment of a possible increase in risk due to consumption of non-edible parts. The highest content of uranium, of 80.2 µg/kg, was found in the edible part of the carrot. The highest activity concentrations of uranium isotopes are found in carrot, potato and onion, as edible parts of these vegetables are grown in the soil. All estimated cancer risks for uranium isotopes range from 10−14 to 10−12, which are insignificant values.

Gamma-ray spectrometry of the Araguainha impact structure, Brazil: Additional insights into element mobilization due to hydrothermal alteration.

We present the analysis of airborne and ground gamma-ray spectrometry signatures of the Araguainha impact structure, located in central Brazil, the largest impact structure in South America with ~ 40 km diameter. The airborne data are total gamma-ray counts per second collected along flight lines spaced 1 km apart. The ground gamma-ray data are concentrations of potassium, uranium, and thorium isotopes calculated from radiations measured in three individual channels. The objectives are to distinguish lithologies within the structure, which have naturally distinctive radiogenic signatures, and identify potential post-impact hydrothermal alteration zones, as indicated by high K concentrations. Based on results obtained by numerical modeling of the crater formation, we infer the locations of potential occurrences of target rocks that may have undergone hydrothermal alteration as a result of the impact. The deviations from the background potassium concentration show significant anomalous K values at the center and in the northwestern crater rim, where high concentrations of U are also observed. The numerical model shows that ideal temperature conditions for hydrothermal fluid circulation were attained right after pos-impact gravitational stabilization.

Uranium isotopes in groundwater in Ho Chi Minh City and related issues: Health risks, environmental effects, and mitigation methods

Groundwater is regularly used for many purposes, such as drinking and agricultural irrigation systems. Still, it contains high levels of radionuclides (e.g., 238U, 232Th, and 226Ra) that are potentially hazardous to humans and the environment. In this study, activity concentrations of uranium isotopes were analyzed in 15 groundwater samples taken from 15 bored wells in Thu Duc district, Ho Chi Minh City, Vietnam. Environmental effects of the irrigation system with groundwater on agricultural soil in the study area were assessed by models. It was found that the activity concentrations of 238U and 234U in groundwater samples were in the ranges of (13.5–268.7) mBq l−1 and (20.2–438.3) mBq l−1, respectively. The ratio 234U/238U values were ranged from 1.12 to 2, with an average value of 1.44. Based on the model prediction, 25 years irrigation with the groundwater can inject 94.8 Bq both uranium isotopes in 1 kg topsoil. For investigated groundwater samples, the proposed removal method using K2FeO4 removed 74.28% and 81.04% for 234U and 238U, respectively.

Sample matrix influence on the efficiency function modeling for uranium isotopes determination by gamma spectrometry

The aim of the presented study was to explore the influence of precise determination of sample matrix in order to obtain reliable gamma spectrometry results. The test was done using two different approaches which have the same goal: quantifying the activity concentration of uranium isotopes in different samples found in the former uranium ore deposit Mazdreja. The first approach is based on iterative methodology, which utilizes the characteristic of a sample that can be quantified before gamma spectrometric measurement. Density of the sample and calculated mass fractions of its constituents (which vary in each iteration) can help to obtain the efficiency function from which activity concentrations of 235U and 238U can be derived and corresponding masses of uranium for the next iteration. In this approach LabSOCS software is used in order to obtain appropriate efficiency. The second approach that was tested represents semiempirical method which applies Monte-Carlo simulations through Geant4 and EFFTRAN software codes for the purposes of generating the detection efficiency functions needed for further calculations.The idea was to compare different methods for uranium activity concentration determination in sample matrices with high uranium mass content and also establish the need for precise calculation (described within the iterative method) by quantifying the relative deviation in activities, calculated by using different methods.From the obtained results, it can be seen that it is very important to adjust the sample matrix to correct composition if we need a precise gamma spectrometry result. But if there is a need to get results in a short period of time, then for the estimation of the activity concentration of the analyzed sample an approximate sample composition can be used. All three tested analyzed methods gave comparable results inside 15% of difference. The major difference was obtained by EFFTRAN software, but on the other side this software is user-friendly and the results can be obtained faster than by using other analysis methods presented in this study.

Uranium Concentrations and Some Physicochemical Parameters of Water Samples at Marshes (Ahwar) in Dhi-Qar Governorate

The solid-state nuclear track detector techniques were used in this study to measure the level of uranium isotopes (238U, 235U, and 234U) that were found in water samples collected from marshes (Ahwar) at Dhi-Qar governorate, southern Iraq. The apparatus used for this study purposes was TASTRAK CR-39 plastic. In this study, we measured the following risk factors: the radiological risk, annual effective dose (ET) of uranium isotopes, the excess cancer risks, the chemical toxicity risk, lifetime average daily dose (LADD), and hazard quotient (HQ). Using different techniques, the water samples were analyzed for other physicochemical properties such as hydrogen ion concentration (PH), electrical conductivity (EC), and total dissolved solids (TDS). This study has proved that uranium isotopes were found in different concentrations in all water samples that were taken from different places of marshes. The concentrations of uranium isotopes in the collected samples were ranging from 0.87±0.072 to 1.89±0.093 μg/L, with an average value of 1.23±0.05 μg/L. The average values (with SE in Bq/L units) for 238U, 235U, and 234U were 1.51±0.06, 0.07±0.002, and 1.53±0.06, respectively, while the average values of ET, LADD, and HQ were 0.107±0.004 mSv/year, (0.326±0.013) × 10−3, 0.040±0.001 μg/kg.day, and 0.066±0.002, respectively. In addition to the previous results, the study has showed that the average value of PH, EC, and TDS with the SE were 7.84±0.22, 3999.95±294.45 μS/cm, and 2601.35±197.77 mg/L, respectively. The results revealed that the concentrations of uranium isotopes in the studied samples were below the instrumental detection limit (1.9 μg/L). Comparing the results of radiological risk and chemical toxicity risk of this study with those published by global organization and universal researches, it was found that these concentrations were within the allowed limits permissible to human consumption and domestic use. Besides these results, the values of EC and TDS were higher than the permissible limits of Iraqi and international standards for irrigation purposes. For all the aforementioned, it might be concluded that there are no health risks to humans by drinking the water of the marshes of Dhi-Qar Governorate according to uranium levels, but cannot be assumed to be of good quality.

Distribution of uranium isotopes in groundwater of the UAE: environmental radioactivity assessment

Occurrence of uranium isotopes in groundwater provides a tracer technology for quality, sources, and recharge conditions. Groundwater samples collected from different aquifer types (sand dune, Quaternary clastics, ophiolite, carbonates and sabkha) in the UAE were analyzed for 238U and 235U. In addition to uranium isotopes, monitoring indicators also cover groundwater pH, temperature and TDS. The concentration of uranium isotopes (238U + 235U) range from 4 to 69,745 ng/L. The distribution of the isotopes in the groundwater of the UAE can be linked to aquifer lithological variability, distance from recharge front and seawater intrusion. In general, about 3% of the groundwater analyzed have uranium concentration above the WHO permissible limit for drinking water.

Radioactive uranium and cesium levels in Kuwait Bay seawater

The development of a continuous radioisotope monitoring program has an extreme significance in maintaining the marine environment’s radiological safety. This study aimed to evaluate the radiological safety of locally sourced desalinated water and seafood. The establishment of baseline data for observing the nuclear activities already existing in the Gulf region was also targeted. While natural uranium radioisotopes are naturally occurring in the environment, there is a rising concern in Kuwait due to the depleted uranium (DU) presence after the Gulf War in 1991. The anthropogenic radionuclide (137Cs) serves as among the most important indicator of the radioactivity releases. The present work focused on determining the concentration of 137Cs and uranium isotopes in Kuwait Bay (KB) seawater. The concentrations of 137Cs were determined by the ammonium molybdenum phosphate (AMP) co-precipitation method followed by gamma spectrometry measurement, whereas a radiochemical separation using anion exchange chromatography and alpha spectrometry measurement was used for uranium isotope determination. The average concentration levels of 235U, (234U and 238U), and 137Cs were 2.3 mBq l−1 ± 0.4, 45.3 mBq l−1 ± 3.5, and 1.24 mBq l−1 ± 0.5, respectively, and these figures are comparable to those reported worldwide. The concluded isotopic ratio of 235U/238U and 234U/238U indicated that the existing uranium in seawater of KB is only natural and no indication of the DU. The produced radiological data are considered as a beneficial baseline for monitoring the regional marine environment.

Radioactivity content in volcanic rocks and radionuclides transfer from rocks to groundwater at Mt. Etna volcano

The paper presents the results of a radiological survey carried out on the eastern flank of Mt. Etna over an area of approximately 120 km 2 . Activity concentrations of uranium isotopes 238,234 U, thorium isotopes 232,230,228 Th, two radium isotopes 226,228 Ra from 238 U and 232 Th decay chains and potassium 40 K were determined using the a- and g- nuclear spectrometry techniques. All rock samples presented activity concentrations of U, Th and Ra in the range between 20 Bq/kg to about 90 Bq/kg, showing a comparable radioactivity content in the whole investigated area. Based on their respective elemental concentrations, the isotopic ratios between different isotopes were studied to draw conclusions on the presence of radioactive equilibrium or disequilibrium in the decay chains. Moreover, an attempt to calculate radionuclide transfer factors from soil to water was made. On the basis of the evaluated concentrations, the radiological risk resulting from ingestion of these isotopes with drinking water was calculated. The obtained results were compared with the regulations currently in force regarding the quality of drinking water.

Study of hydrogen generation and radionuclide release during wet damaged oxide spent fuel storage

The paper describes the outcomes of the experiments to study hydrogen and gaseous fission products accumulation during simulations of the wet damaged VVER-440 SNF storage in air-tight canisters with the water drained and no drying conducted. Physical and chemical processes occurring during the damaged oxide SNF storage in wet environment are discussed. The experiments were carried out in two stages: 1) preliminary soaking of fine fuel particles in water in an air-tight canister, 2) water draining and keeping the wet SNF in the air-tight canister. The experiments were conducted one after another using the same SNF canister and differing only in the SNF soaking temperature, i.e. 25 and 80 °С. The radionuclide release into the liquid phase during the SNF storage under water was studied. Uranium and cesium isotopic concentrations were found to reach steady values when the SNF is kept under water for more than a month. The kinetics of hydrogen and gaseous fission product accumulation in the gaseous phase during wet storage of the spent fuel in the air-tight canister with the water drained coincide for both experiments. The kinetics demonstrate an abrupt decrease of the hydrogen and gaseous fission product accumulation rate in 46 hours. The data obtained can be applied for development and verification of the damaged SNF behavior models during SNF storage in wet environment under radiolysis.

234U/238U activity ratios in groundwaters from two aquifers in Saudi Arabia, and correlation with water chemistry

The purpose of this study was to determine the activity concentrations of uranium isotopes (234U and 238U) and the 234U/238U activity ratios in groundwater wells from Saudi Arabia. These wells are located in two different regions and tapping different aquifers. The uranium isotopes were measured by alpha spectrometry. The uranium activity ratios (234U/238U) in the investigated samples had an average value of 1.38 and ranged from 1.0 to 2.17. The relationship between the activity concentrations of the combined uranium and the water chemical composition in the studied wells was also investigated. Good correlation was found with redox potential described by R2 value of 0.74. Also, a good negative correlation was observed between The TDS content of the groundwater samples and the uranium activities described by R2 value of 0.59. Finally, with twenty groundwater samples collected from two large areas, the presence of uranium isotopes in the Saq and Dammam aquifers can't be easy to judge but within the framework of this study, it can be concluded that the distribution of 238U and 234U in these two aquifers is more dependent on the mineralogical composition of the aquifer matrix and by the geochemical/hydrochemical conditions present.

Methodology for preliminary assessment of the radioactivity in natural waters

Abstract This article presents the results of a preliminary assessment of the radioactivity of natural waters and the isotope analysis of drinking water. It describes the methods for the radiochemical preparation of water samples, which include concentration of uranium isotopes from water samples, extraction from impeding radionuclides and preparation of electrically countable samples. The results of violation of radioactive equilibrium between the isotopes 234U/238U and the several factors affecting this process in water samples have been obtained. It is clear from the obtained result that 234U isotope concentration in groundwater is higher than that in surface water.

Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media

Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials.

The detailed analysis of natural radionuclides dissolved in spa waters of the Kłodzko Valley, Sudety Mountains, Poland

A survey was conducted to measure natural radioactivity in spa waters from the Kłodzko Valley. The main goal of this study was to determine the activity concentration of uranium, radium and radon isotopes in the investigated groundwaters. Samples were collected several times from 35 water intakes from 5 spas and 2 mineral water bottling plants. The authors examined whether the increased gamma radiation background, as well as the elevated values of radium and uranium content in reservoir rocks, have a significant impact on the natural radioactivity of these waters.The second objective of this research was to provide information about geochemistry of U, Ra, Rn radionuclides and the radiological and chemical risks incurred by ingestion of isotopes with drinking water. On the basis of results obtained, it is feasible to assess the health hazard posed by ingestion of natural radioactivity with drinking waters. Moreover, the data yielded by this research may be helpful in the process of verification of the application of these waters in balneotherapy.In addition, annual effective radiation doses resulting from the isotopes consumption were calculated on the basis of the evaluated activity concentrations. In dose assessment for uranium and radium isotopes, the authors provided values for different human age groups. The obtained uranium content in the investigated waters was compared with the currently valid regulations concerning the quality of drinking water. Based on the activity concentrations data, the activity isotopic ratios 234U/238U, 226Ra/238U, 222Rn/238U, 222Rn/226Ra and the correlations between radionuclides content were then examined. In brief, it may be concluded on the basis of the obtained results that radon solubility is inversely proportional to radium and uranium dissolution in environmental water circulation. The presented study allows conclusions to be drawn on the radionuclide circulation among different environmental biota: from lithosphere through hydrosphere to biosphere.

Concentration of uranium in the drinking and surface water around the WIPP site

Activity concentration of uranium isotopes (238U, 234U and 235U) were analyzed in drinking and surface water samples collected in the vicinity of the WIPP site using alpha spectroscopy. The purpose of this study was to investigate the changes in uranium concentrations (if any) in the vicinity of the WIPP site and whether the February 14, 2014 radiation release event at the WIPP had any detectable impact on the water bodies around the WIPP.