Elevated Levels Of Uranium Research Articles

Quantification of natural uranium and its risk evaluation in groundwater of Chikkaballapur district in Karnataka, India.

The present study focused on the distribution of uranium in groundwater samples collected from various sources in the Chikkaballapur district and its associated risk in humans. Seventy-five groundwater samples were collected during pre-monsoon and post-monsoon seasons and were analysed for uranium concentration along with different water quality parameters. The uranium concentration ranged from 0.23 to 285.23µg/L in the pre-monsoon season and from 0.02 to 107.87µg/L in the post-monsoon season. More than 90% of samples, except a few, were under the safe limits of 60µg/L as directed by the Department of Atomic Energy (DAE) of India's Atomic Energy Regulatory Board (AERB). The study analysed physicochemical parameters like pH, total dissolved solids (TDS), nitrate, total hardness, phosphate, sulphate and fluoride in collected water samples. Out of all samples, few samples noted higher values of TDS, nitrate and fluoride. Their correlation along with uranium is detailed in the study. Owing to its slightly elevated content, an evaluation of the radiological and chemical hazards associated with uranium consumption was analysed. When the risk resulting from chemical toxicity was evaluated, relatively few samples had a hazard quotient (HQ) score higher than 1, which suggested that the people were vulnerable to chemical danger. This study also evaluates the dangers of elevated uranium levels in groundwater samples to the general public's health. It also acknowledges the importance of routinely evaluating and treating the drinking water sources in the region.

Groundwater uranium contamination from produced water disposal to unlined ponds in the San Joaquin Valley

In the southern San Joaquin Valley (SJV) of California, an agriculturally productive region that relies on groundwater for irrigation and domestic water supply, the infiltration of produced water from oil reservoirs is known to impact groundwater due to percolation from unlined disposal ponds. However, previously documented impacts almost exclusively focus on salinity, while contaminant loadings commonly associated with produced water (e.g., radionuclides) are poorly constrained. For example, the infiltration of bicarbonate-rich produced waters can react with sediment-bound uranium (U), leading to U mobilization and subsequent transport to nearby groundwater. Specifically, produced water infiltration poses a particular concern for SJV groundwater, as valley-fill sediments are well documented to be enriched in geogenic, reduced U. Here, we analyzed monitoring well data from two SJV produced water pond facilities to characterize U mobilization and subsequent groundwater contamination. Groundwater wells installed within 2 km of the facilities contained produced water and elevated levels of uranium. There are >400 produced water disposal pond facilities in the southern SJV. If our observations occur at even a fraction of these facilities, there is the potential for widespread U contamination in the groundwaters of one of the most productive agricultural regions in the world.

Cold season dose rate contributions from gamma, radon, thoron or progeny in legacy mines with high natural background radiation.

In areas with high natural background radiation, underground cavities tend to have high levels of airborne radionuclides. Within mines, occupancy may involve significant exposure to airborne radionuclides like radon (222Rn), thoron (220Rn) and progeny. The Fen carbonatite complex in Norway has legacy mines going through bedrock with significantly elevated levels of uranium (238U) and especially thorium (232Th), and significant levels of their progeny 222Rn and 220Rn. There are also significantly elevated levels of gamma radiation in these mines. These mines are naturally chimney ventilated and release large volumes of air to the outdoors giving a large local outdoor impact. We placed alpha track detectors at several localities within these mines to measure airborne radionuclides and measured gamma radiation of bedrock at each locality. The bedrock within the mines shows levels up to 1900Bqkg-1 for 238U, 12000Bqkg-1 for 232Th and gamma dose rates up to 11μSvh-1. Maximum levels of airborne radionuclides were 45000Bqm-3 for 220Rn and 6900Bqm-3 for 222Rn. In addition, we measured levels of thoron progeny (TnP). In order to estimate radiation dose contribution, TnP should be assessed rather than 220Rn, but deposition-based detectors may be biased by the airflow of mine-draft. We present dose rate contributions using UNSCEAR dose conversion factors, and correcting for airflow bias, finding a combined cold season dose rate within these mines of 17-24μSvh-1. Interestingly, fractional dose rate contributions vary from 0.02 to 0.6 for gamma, 0.33 to 0.95 for radon and 0.1 to 0.25 for TnP.

Assessment of the groundwater quality by using multivariate approach and non-carcinogenic risk of uranium in the inhabitants of the Bastar district, Chhattisgarh, Central India

Abstract The elevated levels of uranium found in 17 states of India is alarming due to the radionuclide contamination in groundwater. Chronic ingestion can cause potential harm to humans and living things such as damage to kidneys, and cancer of the liver, lungs, and bones. The present study was undertaken to assess groundwater quality using a multivariate approach to the non-carcinogenic exposure of uranium by residents of the Bastar district, Chhattisgarh. The concentration of uranium in groundwater samples ranged from 0.50–26.4 μg/l in 70 samples, with 82% of samples being beyond the recommended limits by the International Commission on Radiological Protection. Hierarchical cluster analysis divided all sampling locations into 10 clusters explaining the similarity of geological conditions. Factor analysis extracted four principal components or factors with 70.20% cumulative variance from the entire data set. Chronic daily intake has been found above from the reference dose as 34.29, 42.86, and 51.43% for young children, children and adults. The results of hazard quotient analysis classified the degree of non-carcinogenic risk which was >1 in 34.28, 45.71, and 41.43% for the samples from young children, children and adults, respectively. This study will generate baseline data and suggest the need for revision of water quality monitoring plans and preventive water management practices.

Traditional Sheep Consumption by Navajo People in Cameron, Arizona.

Over 500 abandoned uranium mines are located on the Navajo Reservation. Different pathways of environmental uranium exposure have been studied with respect to the Navajo people including water, soil, and plants; however, uranium exposure from traditional Navajo food, specifically mutton (sheep), has not been reported. This study focuses on mutton consumption in the small community of Cameron, Arizona, located in the southwestern region of the Navajo Nation and initiated after community members expressed concern with the uranium exposure of their sheep. Preliminary investigation into the presence of uranium in sheep raised near Cameron showed elevated uranium levels in the kidneys the sheep tested. The goal of this study is to investigate mutton consumption among the Navajo living in Cameron. Mutton is a traditional food of the Navajo, but consumption practices are not well documented. An important aspect of determining the extent of exposure through food consumption is to assess the frequency of consumption. The results of this study indicate the Cameron participants consume mutton most commonly at family gatherings or celebrations. The survey suggests that less mutton is consumed now compared to the past, and there is concern that contaminated mutton may change traditional ceremonies.

Determinations of uranium concentrations in soil, water, vegetables and biological samples from inhabitants of war affected areas in eastern Croatia (ICP-MS method)

The occurrence of elevated uranium levels in post-war areas raise concerns among populations, especially in areas affected by heavy bombardment and potential use of depleted uranium weapons. The aim of this study was to assess public exposure to the uranium Water, soil, vegetables, urine, serum and hair samples were collected for the first time in eastern Croatia and analysed using an inductively coupled plasma mass spectrometry (ICP-MS) method, in order to try to explain the possible origins of uranium in the population and environment. Urine, serum and hair samples were collected from 389 inhabitants. A large variation of uranium concentrations in urine, serum and hair samples was found in this study. The majority of urine, serum and hair samples from our study had uranium concentrations below the reference literature values. A higher uranium concentration in the hair of 4% of inhabitants, mostly from rural areas, could not be explained at this stage of research. A further, extended epidemiological study should be made of uranium in the region.

Study of uranium toxicity using low-background gamma-ray spectrometry

The natural activity of 238U, 232Th and 40K present in soil, fertilizer and palaeosols besides animal fossils was determined using low background gamma ray spectrometry. The highest uranium activity level were found in animal fossils of geogenic origin compared to palaeosols, soils and fertilizers, a result of post-mortem uranium assimilation in these fossils via diagenetic processes. Hence, geogenic mobilization is likely a major cause of elevated uranium levels in Malwa region of Punjab, also known for higher than normal cancer incidence.

Structural changes in amber due to uranium mineralization

The presence of uranium, with a bulk mass fraction of about 1.5 wt% and radiolytic alterations are a feature of Cenomanian amber from Křižany, at the northeastern edge of the North Bohemian Cretaceous uranium ore district. Pores and microcracks in the amber were filled with a mineral admixture, mainly in the form of Zr-Y-REE enriched uraninite. As a result of radiolytic alterations due to the presence of uranium, structural changes were observed in the Křižany amber in comparison with a reference amber from Nové Strašecí in central Bohemia; this was of similar age and botanical origin but did not contain elevated levels of uranium. Structural changes involved an increase in aromaticity due to dehydroaromatization of aliphatic cyclic hydrocarbons, loss of oxygen functional groups, an increase in the degree of polymerization, crosslinking of CC bonds, formation of a three-dimensional hydrocarbon network in the bulk organic matrix, and carbonization of the organic matrix around the uraninite infill.

Investigating arsenic (As) occurrence and sources in ground, surface, waste and drinking water in northern Mongolia

Elevated levels of arsenic in drinking water are found in several parts of Asia. Prolonged intakes of even low concentrations typically have serious health effects. This research paper integrates results of various studies on arsenic contamination of ground, surface, waste and drinking water in north-central Mongolia. Samples were analyzed with the ARSOlux biosensor and the Arsenator field test kit as well as different spectrometric methods (ICP-MS, ICP-OES). Altogether 309 samples were tested for their arsenic concentration, 44 of them with more than one technique. In the study region, the enrichment of heavy metals in surface waters is often linked to mining and coal combustion. The highest concentration of arsenic (As) was detected in the effluent of a gold mine (up to 2,820 μg L−1) and in the ash basin of a thermal power plant (up to 1,170 μg L−1). Five of 54 drinking water samples and 16 of 184 river samples were found to contain As levels above the World Health Organization (WHO) maximum permissible limit (10 μg L−1), with a maximum of 300 μg L−1 As. In addition, elevated levels of uranium were detected. The degree and extent of As concentrations exceeding WHO standards were previously unknown and demonstrate the necessity for a more intensive screening as well as possible interventions concerning the intake of arsenic-contaminated drinking water. Preliminary results indicate that the ARSOlux biosensor technology is well suited for a precise quantification of arsenic content at low detection limits in regions where access to central laboratories is difficult.

Do metals that translocate to the brain exacerbate traumatic brain injury?

Metal translocation to the brain is strictly controlled and often prevented by the blood–brain barrier. For the most part, only those metals required to maintain normal function are transported into the brain where they are under tight metabolic control. From the literature, there are reports that traumatic brain injury disrupts the blood–brain barrier. This could allow the influx of metals that would normally have been excluded from the brain. We also have preliminary data showing that metal pellets, surgically-implanted into the leg muscle of a rat to simulate a shrapnel wound, solubilize and the metals comprising the pellet can enter the brain. Surprisingly, rats implanted with a military-grade tungsten alloy composed of tungsten, nickel, and cobalt also showed significantly elevated uranium levels in their brains as early as 1month after pellet implantation. The only source of uranium was low levels that are naturally found in food and water. Conversely, rats implanted with depleted uranium pellets demonstrated elevated uranium levels in brain resulting from degradation of the implanted pellets. However, when cobalt levels were measured, there were no significant increases in the brain until the rats had reached old age. The only source of cobalt for these rats was the low levels found in their food and water. These data suggest that some metals or metal mixtures (i.e., tungsten alloy), when embedded into muscle, can enhance the translocation of other, endogenous metals (e.g., uranium) across the blood–brain barrier. For other embedded metals (i.e., depleted uranium), this effect is not observed until the animal is of advanced age. This raises the possibility that metal body-burdens can affect blood–brain barrier permeability in a metal-specific and age-dependent manner. This possibility is disconcerting when traumatic brain injury is considered. Traumatic brain injury has been called the “signature” wound of the conflicts in Iraq and Afghanistan, often, an embedded metal fragment wound occurs simultaneously. Since the blood–brain barrier can be disrupted by traumatic brain injury, this raises the possibility of free access to the brain for any metals found in the body. Therefore, we hypothesize that this influx of metals overwhelms normal brain homeostasis, depletes the brain’s antioxidant defense systems, and activates microglial cells resulting in the release of inflammatory mediators that can potentially exacerbate the adverse effects of traumatic brain injury.

Risk assessment (chemical and radiological) due to intake of uranium through the ingestion of drinking water around two proposed uranium mining areas, Jharkhan d, India

Uranium is known for both chemical and radiological toxicity. East Singhbhum is known for uranium mining, and radionuclides can be expected in its groundwater. Groundwater was collected around two proposed sites of Bagjata and Banduhurang and analysed for U(nat). The study reveals that the U(nat) varied from for the Bagjata and Banduhurang mining areas, respectively. The excess lifetime cancer risk due to the consumption of uranium in water was calculated to be in the range of 8.81 × 10-6 to 4.34 × 10-5 and 3.36 × 10-6 to 9.55 × 10-5 for the two study areas, which are within the acceptable cancer risk value of 1 × 10-4 . However, the risk at a few locations is very close to the threshold value. The chemical risk evaluated by the hazard quotient was found to be within 0.05–0.23 and 0.02–0.6 for the two study areas and did not exceed the limit of 1. Thus, the concentration of U(nat) in the groundwater presently does not pose any serious threat to local people but must be monitored periodically and adequate actions must be taken in the few areas with elevated levels of uranium in the groundwater.

A model for uranium mobility in groundwater in the Grand Pré region, Nova Scotia, Canada

Elevated levels of uranium that surpass maximum allowable concentrations have been recognized in some well water samples throughout Nova Scotia. In this study we examine the influence of redox conditions and regional geology on the mobility of uranium in groundwater in the Grand Pré region, located in the eastern end of the Annapolis-Cornwallis Valley in southwestern Nova Scotia. The study site is underlain by carbon-rich shale and arkosic sandstone of the Late Mississippian Horton Bluff Formation and the arenaceous sandstone of the Triassic Wolfville Formation. Water samples from drilled wells were analyzed on site for various water quality parameters (pH, conductivity, temperature, dissolved oxygen) and in the laboratory to determine alkalinity and cation (72) and major anion (9) concentrations.
 
 Several samples exceeded Health Canada (2011) limits for uranium (20 μg/L) with values up to 50.8 μg/L and aesthetic objectives (AO) for iron (up to 605 μg/L), manganese (up to 2.28 mg/L) and other cations. Data show that different redox conditions occur in the study area. The geospatial arrangement of the chemical data suggests that the lithology of the underlying aquifer strongly influences the availability of uranium in groundwater. Reduced groundwater in Horton Bluff sandstone typically contains elevated concentrations of Fe 2+ and Mn 2+ , whereas groundwater containing high concentrations of U is found primary in oxidizing environments in quartz arenite sandstone units in the Wolfville Formation.
 
 Consumption of groundwater in the Grand Pré region may pose a health risk; however, the level of risk remains unknown. This study emphasizes that in the area of Grand Pré, water that is considered aesthetically undesirable (containing high Fe and Mn) may pose less of a health risk (low U) than waters that are aesthetically pleasing.

High levels of uranium in groundwater of Ulaanbaatar, Mongolia

Water samples collected from 129 wells in seven of the nine sub-divisions of Ulaanbaatar were analyzed by inductively coupled plasma mass spectrometry (ICP–MS) using Clean Lab methods. The levels of many trace elements were found to be low with the average concentrations (ranges in brackets) being 0.9 (<0.1–7.9)μg/L for As; 7.7 (0.12–177)μg/L for Mn; 0.2 (<0.05–1.9)μg/L for Co; 16 (<0.1–686)μg/L for Zn; 0.7 (<0.1–1.8)μg/L for Se; <0.1 (<0.02–0.69)μg/L for Cd; and 1.3 (<0.02–32)μg/L for Pb. The levels of uranium were surprisingly elevated (mean, 4.6μg/L; range <0.01–57μg/L), with the values for many samples exceeding the World Health Organization's guideline of 15μg/L for uranium in drinking water. Local rocks and soils appear to be the natural source of the uranium. The levels of uranium in Ulaanbaatar's groundwater are in the range that has been associated with nephrotoxicity, high blood pressure, bone dysfunction and likely reproductive impairment in human populations. We consider the risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar to be a matter for some public health concern and conclude that the paucity of data on chronic effects of low level exposure is a risk factor for continuing the injury to many people in this city.

Bioavailability and microbial adaptation to elevated levels of uranium in an acid, organic topsoil forming on an old mine spoil

An old mine spoil at a 19th-century mining site with considerable residues of uranium (400-800 mg U/kg) was investigated with respect to U concentrations in soil and plants and tolerance to U in the soil microbial community in order to describe the bioavailability of U. Measurements of soil fractions representing water-soluble U, easily exchangeable U, and U bound to humified organic matter showed that all fractions contained elevated concentrations of U. Plant U concentrations were only 10 times higher at the mine spoil site compared to the reference site (3 mg U/kg vs 0.3 mg U/kg), while the most easily available soil fractions contained 0.18 to 0.86 mg U/kg soil at the mine spoil. An ecotoxicity bioassay using incorporation of [3H]thymidine into the indigenous microbial communities of the two soils in the presence of increasing U concentrations showed that microorganisms at the mining site were sensitive to U but also that they had acquired a substantial tolerance toward U (EC50, the effective concentration reducing activity by 50% of UO2-citrate was approximately 120 microM as compared to 30 microM in the reference soil). In the assay, more than 40% of the microbial activity was maintained in the presence of 1 mM UO2-citrate versus 3% in the reference soil. We conclude that U-enriched mining waste can contain sufficiently elevated concentrations of bioavailable U to affect indigenous microorganisms and that bioavailable U imposes a selection pressure that favors the development of a highly uranium-tolerant microbial community, while plant uptake of U remains low.

Indoor radon in rural dwellings of the South-Pannonian region

The results of indoor radon survey in the South-Pannonian Province Vojvodina (Serbia and Montenegro) are presented. The sampling strategy was oriented towards suburban and urban regions in the Province. For the dwellings typical for such regions the geometric mean annual radon activity concentration of 76.1 Bq m(-3) is measured (1000 measurements). This result leads to the annual dose estimate of 4.3 mSv y(-1), which is above the recommended action limit of ICRP. For urban dwellings in Novi Sad (the Province capital), the annual mean value of 54 Bq m(-3) (220 measurements) is obtained. By comparison of these two results it is concluded that radon surveys based on measurements in urban environment may seriously underestimate the radon-related health risk. The elevated radon levels could not be explained by elevated uranium levels of surface soil.

Uranium pollution of South African streams ? An overview of the situation in gold mining areas of the Witwatersrand

During more than a century of gold mining in South Africa large amounts of tailings were produced, which now cover vast areas in densely populated regions. These dumps contain elevated levels of uranium and other toxic heavy metals associated with gold in the mined ore. Large-scale extraction of uranium from auriferous ore only took place during the cold war, leaving tailings with high uranium concentrations that were deposited before and after this period. Recent studies found elevated levels of the radioactive heavy metal in groundwater and streams, mainly attributed to the discharge of contaminated water from mines. In this paper the contribution of seepage from slimes dams to the uranium pollution of adjacent streams is analysed. Based on geochemical analyses of samples, field observations and long-term in situ measurements of hydraulic and hydrochemical parameters at selected mining sites across the Witwatersrand goldfields, the extent, mechanisms and dynamics of diffuse stream contamination by tailings seepage is characterised. Temporal and spatial variations of the process and the associated hazard potential are discussed.

Accumulation of uranium by filamentous green algae under natural environmental conditions

The capacity of algae to concentrate uranium under natural environmental conditions is measured by a-spectrometry. Spirogyra, a filamentous green fresh-water alga, has concentrated uranium from a surface concrete ponds with elevated uranium levels (140-1140 ppb). The concentration factors (CFs) ranged from 8.9-67 with an average value of 22.Cladophora spp, a filamentous green marine alga has concentrated uranium from the marine water with a concentration factor ranged from 220–280. The average concentration factor was 250. The factors affecting the sorption process are discussed in detail.

Uranium gastrointestinal absorption: the F1 factor in humans

The present investigation was undertaken by the Department of Health, Canada, to determine the most appropriate value to use for uranium gastrointestinal absorption (f1) in setting the guideline for drinking water. Fifty participants, free from medical problems, were recruited from two communities: a rural area where drinking water, supplied from drilled wells, contained elevated levels of uranium and an urban area where the water supplied by the municipal water system contained < 1 microg l(-1). Uranium intake through food, drinking water and other beverages was monitored using the duplicate diet approach. Intake and excretion were measured by inductively coupled plasma-mass spectrometry (ICP-MS) in samples collected concurrently from the same individuals over a 3 d period. The range of f1 values was between 0.001 and 0.06, with a median of 0.009. These values were independent of gender, age, duration of exposure, daily total uranium intake and allocation of intake between food and water. Consistent with the recommendation of ICRP Publication 69, 78% were below 0.02.

Comparative sensitivity of three populations of the cladoceran Moinodaphnia macleayi to acute and chronic uranium exposure

Assessment of differences in the response of three different populations of the tropical cladoceran Moinodaphnia macleayi to uranium exposure was evaluated. The populations tested included a laboratory stock (maintained for 10 years), a wild population collected from Bowerbird Billabong (an uncontaminated environment), and a population collected from Djalkmara Billabong (a relatively contaminated environment with elevated levels of uranium), located on the Ranger uranium mine site, Jabiru East, NT, Australia. Chronic and acute toxicity of uranium was determined for all three populations. The no-observed-effect-concentration (NOEC; reproduction) and lowest observed-effect-concentration (LOEC; reproduction) for uranium ranged between 8-31 micrograms L-1 and 20-49 micrograms L-1, respectively, for all three populations. The 48 h EC50 (immobilization-lethality) for uranium ranged between 160-390 micrograms L-1 for all three populations. There was little difference in the response of the three populations of M. macleayi to acute and chronic uranium exposure, although the response of the laboratory population to chronic uranium exposure appeared more variable than the "wild" populations. There was no apparent tolerance in the population of M. macleayi obtained from Djalkmara Billabong when exposed to elevated levels of uranium. M. macleayi was significantly more sensitive to uranium exposure than other species previously tested. It was concluded that the sensitivity of the laboratory population (to uranium) is still representative of natural M. macleayi populations.

Spectroscopic characterization of uranium in evaporation basin sediments

Evaporation ponds in the San Joaquin Valley (SJV), CA, used for the containment of irrigation drainage waters contain elevated levels of uranium (U) resulting from the extensive leaching by carbonate-rich irrigation waters of the local agricultural soils that contain low levels of naturally-occurring U. The SJV ponds are subjected to changes in redox chemistry with cycles of drying and flooding. Our past studies have shown that U in the SJV Pond 14 surface sediments is present as mostly the oxidized and soluble form, U(VI). However, we were uncertain whether the U in the soil was only present as a U oxide of mixed stoichiometry, such as U 3O 8(s) (pitchblende) or other species. Here we present characterization information, which includes wet chemical and in situ spectroscopic techniques (X-ray absorption near-edge structure (XANES) and low temperature time-resolved luminescence spectroscopies) for samples from two SJV Pond sediments. Surface sediments from SJV Pond 16 were characterized for average oxidation state of U with XANES spectroscopy. The fraction of U(VI) to U(IV) in the Pond 16 sediments decreased with depth with U(IV) being the dominant oxidation state in the 5 cm to 15 cm depth. Two luminescent U(VI) species were identified in the surface sediments from Pond 14; a U(VI)-tricarbonate phase and another phase likely comprised of U(VI)-hydroxide or hydroxycarbonate. The luminescent U(VI) population in the Pond 16 sediments is dominated by species with comparable spectral characteristics to the U(VI)-hydroxide or hydroxycarbonate species found in the Pond 14 sediments. The luminescence spectroscopic results were complemented by wet chemical U leaching methods, which involved the use of carbonate and sulfuric acid solutions and oxidizing solutions of peroxide, hypochlorite and Mn(IV). Leaching was shown to decrease the total U concentration in the sediments in all cases. However, results from luminescence studies of the residual fraction in the leached sediments suggest that there was no selectivity in the removal of the spectroscopically identifiable U(VI) species by acidic oxidizing, basic oxidizing or basic non-oxidizing solutions. A net increase in the emission intensity of the U(VI) luminescent species in most leached samples was consistent with conversion of U(IV) to U(VI), as a result of chemical oxidation and exposure to air during the leaching process. The wet chemical extractions and in situ spectroscopic techniques provided fundamental and basic knowledge about the fraction of U(IV) to U(VI), the speciation of luminescent U(VI), and the susceptibility of the sediment U species to leaching.