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Sample records for anthropogenic uranium concentration

  1. On monitoring anthropogenic airborne uranium concentrations and (235)U/(238)U isotopic ratio by Lichen - bio-indicator technique.

    PubMed

    Golubev, A V; Golubeva, V N; Krylov, N G; Kuznetsova, V F; Mavrin, S V; Aleinikov, A Yu; Hoppes, W G; Surano, K A

    2005-01-01

    Lichens are widely used to assess the atmospheric pollution by heavy metals and radionuclides. However, few studies are available in publications on using lichens to qualitatively assess the atmospheric pollution levels. The paper presents research results applying epiphytic lichens as bio-monitors of quantitative atmospheric contamination with uranium. The observations were conducted during 2.5 years in the natural environment. Two experimental sites were used: one in the vicinity of a uranium contamination source, the other one - at a sufficient distance away to represent the background conditions. Air and lichens were sampled at both sites monthly. Epiphytic lichens Hypogimnia physodes were used as bio-indicators. Lichen samples were taken from various trees at about 1.5m from the ground. Air was sampled with filters at sampling stations. The uranium content in lichen and air samples as well as isotopic mass ratios (235)U/(238)U were measured by mass-spectrometer technique after uranium pre-extraction. Measured content of uranium were 1.45 mgkg(-1) in lichen at 2.09 E-04 microgm(-3) in air and 0.106 mgkg(-1) in lichen at 1.13 E-05 microgm(-3) in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C(AIR)=exp(1.1 x C(LICHEN)-12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle.

  2. Uranium concentrations in asparagus

    SciTech Connect

    Tiller, B.L.; Poston, T.M.

    1992-05-01

    Concentrations of uranium were determined in asparagus collected from eight locations near and ten locations on the Hanford Site southcentral Washington State. Only one location (Sagemoor) had samples with elevated concentrations. The presence of elevated uranium in asparagus at Sagemoor may be explained by the elevated levels in irrigation water. These levels of uranium are comparable to levels previously reported upstream and downstream of the 300-FF-1 Operable Unit on the Hanford Site (0.0008 {mu}g/g), but were below the 0.020-{mu}g/g level reported for brush collected at Sagemoor in a 1982 study. Concentrations at all other onsite and offsite sample locations were considerably lower than concentrations reported immediately upstream and downstream of the 300-FF-1 Operable Unit. Using an earlier analysis of the uranium concentrations in asparagus collected from the Hanford Site constitutes a very small fraction of the US Department of Energy effective dose equivalent limit of 100 mrem.

  3. Concentrations and fluxes of dissolved uranium in the Yellow River estuary: seasonal variation and anthropogenic (Water-Sediment Regulation Scheme) impact.

    PubMed

    Juanjuan, Sui; Zhigang, Yu; Bochao, Xu; Wenhua, Dong; Dong, Xia; Xueyan, Jiang

    2014-02-01

    The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19-July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85-7.57 μg l(-1) and (234)U/(238)U activity ratios of 1.24-1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04 × 10(8) g y(-1) was estimated based on the monthly average water discharge and dissolved uranium concentration in the lower reaches of the Yellow River. The amount of dissolved uranium (2.65 × 10(7) g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux.

  4. [Uranium Concentration in Drinking Water from Small-scale Water Supplies in Schleswig-Holstein, Germany].

    PubMed

    Ostendorp, G

    2015-04-01

    In this study the drinking water of 212 small-scale water supplies, mainly situated in areas with intensive agriculture or fruit-growing, was analysed for uranium. The median uranium concentration amounted to 0.04 µg/lL, the 95(th) percentile was 2.5 µg/L. The maximum level was 14 µg/L. This sample exceeded the guideline value for uranium in drinking water. The uranium concentration in small-scale water supplies was found to be slightly higher than that in central water works in Schleswig-Holstein. Water containing more than 10 mg/L nitrate showed significantly higher uranium contents. The results indicate that the uranium burden in drinking water from small wells is mainly determined by geological factors. An additional anthropogenic effect of soil management cannot be excluded. Overall uranium concentrations were low and not causing health concerns. However, in specific cases higher concentrations may occur.

  5. Uranium concentrations in South African herbal remedies.

    PubMed

    Steenkamp, Vanessa; Stewart, Michael J; Chimuka, Luke; Cukrowska, Ewa

    2005-12-01

    South Africa contains some of the world's largest mineral deposits, which include uranium. Uranium is mined as a by-product of gold production. The uranium content of the surface soil and groundwater in South Africa has been measured and shows marked variation, depending on location. Herbal remedies are collected by traditional healers from many sites, some of which may be contaminated. Thirty herbal remedies were analyzed using a sensitive adsorptive stripping voltammetry method. Eight samples had levels below the limit of detection, but in five the levels were greatly elevated, showing concentrations above 40,000 ppb. The mean uranium concentration of the remainder of the specimens was of the order of 15,000 ppb. We have attempted to put these data into context by comparison with other studies of absorption of uranium by the oral route.

  6. Using Pb isotopes in surface media to distinguish anthropogenic sources from undercover uranium sources

    NASA Astrophysics Data System (ADS)

    Kyser, Kurt; Lahusen, Larry; Drever, Garth; Dunn, Colin; Leduc, Evelyne; Chipley, Don

    2015-09-01

    The response in elemental concentrations and Pb isotopes in various surface media from the Cigar West unconformity-type uranium deposit located at a depth of 450 m were measured to ascertain if element migration from the deposit can be detected at the surface. The media included clay-size fractions separated from the A2, B and C soil horizons, and tree cores and twigs from black spruce (Picea mariana) and jack pine (Pinus banksiana) trees. Lead isotopes were used to trace any effect on the surface media from the deposit at depth because the 207Pb/206Pb ratios in the ore are < 0.1, whereas the background values in the basin are > 0.7 and modern anthropogenic Pb from aerosols are near 0.9. The tree cores record their lowest and therefore most radiogenic 207Pb/206Pb ratios of < 0.7 near the surface projection of the deposit and associated structures, particularly in tree rings that predate any exploration and drilling activity in the area. The median 207Pb/206Pb ratios increase in the order C, B soil horizon clays, tree cores, A2 soil clays and twigs because of the increasing contribution of common Pb with high ratios from anthropogenic sources that affect the shallowest media the most. Although this anthropogenic Pb as well as that from the background dominates the composition of all media at the surface and the contribution from the deposit at depth is diminished toward the surface, ore-related Pb is still present as a few percent of the composition of pathfinder elements and Pb isotopes.

  7. Natural and anthropogenic radionuclide activity concentrations in the New Zealand diet.

    PubMed

    Pearson, Andrew J; Gaw, Sally; Hermanspahn, Nikolaus; Glover, Chris N

    2016-01-01

    To support New Zealand's food safety monitoring regime, a survey was undertaken to establish radionuclide activity concentrations across the New Zealand diet. This survey was undertaken to better understand the radioactivity content of the modern diet and also to assess the suitability of the current use of milk as a sentinel for dietary radionuclide trends. Thirteen radionuclides were analysed in 40 common food commodities, including animal products, fruits, vegetables, cereal grains and seafood. Activity was detected for (137)Caesium, (90)Strontium and (131)Iodine. No other anthropogenic radionuclides were detected. Activity concentrations of the three natural radionuclides of Uranium and the daughter radionuclide (210)Polonium were detected in the majority of food sampled, with a large variation in magnitude. The maximum activity concentrations were detected in shellfish for all these radionuclides. Based on the established activity concentrations and ranges, the New Zealand diet contains activity concentrations of anthropogenic radionuclides far below the Codex Alimentarius guideline levels. Activity concentrations obtained for milk support its continued use as a sentinel for monitoring fallout radionuclides in terrestrial agriculture. The significant levels of natural and anthropogenic radionuclide activity concentrations detected in finfish and molluscs support undertaking further research to identify a suitable sentinel for New Zealand seafood monitoring. PMID:26094571

  8. Natural and anthropogenic radionuclide activity concentrations in the New Zealand diet.

    PubMed

    Pearson, Andrew J; Gaw, Sally; Hermanspahn, Nikolaus; Glover, Chris N

    2016-01-01

    To support New Zealand's food safety monitoring regime, a survey was undertaken to establish radionuclide activity concentrations across the New Zealand diet. This survey was undertaken to better understand the radioactivity content of the modern diet and also to assess the suitability of the current use of milk as a sentinel for dietary radionuclide trends. Thirteen radionuclides were analysed in 40 common food commodities, including animal products, fruits, vegetables, cereal grains and seafood. Activity was detected for (137)Caesium, (90)Strontium and (131)Iodine. No other anthropogenic radionuclides were detected. Activity concentrations of the three natural radionuclides of Uranium and the daughter radionuclide (210)Polonium were detected in the majority of food sampled, with a large variation in magnitude. The maximum activity concentrations were detected in shellfish for all these radionuclides. Based on the established activity concentrations and ranges, the New Zealand diet contains activity concentrations of anthropogenic radionuclides far below the Codex Alimentarius guideline levels. Activity concentrations obtained for milk support its continued use as a sentinel for monitoring fallout radionuclides in terrestrial agriculture. The significant levels of natural and anthropogenic radionuclide activity concentrations detected in finfish and molluscs support undertaking further research to identify a suitable sentinel for New Zealand seafood monitoring.

  9. Uranium concentration monitor manual: 2300 system

    SciTech Connect

    Russo, P.A.; Sprinkle, J.K. Jr.; Stephens, M.M.

    1985-04-01

    This manual describes the design, operation, and procedures for measurement control for the automated uranium concentration monitor on the 2300 solvent extraction system at the Oak Ridge Y-12 Plant. The nonintrusive monitor provides a near-real time readout of uranium concentration at two locations simultaneously in the solvent extraction system for process monitoring and control. Detectors installed at the top of the extraction column and at the bottom of the backwash column acquire spectra of gamma rays from the solvent extraction solutions in the columns. Pulse-height analysis of these spectra gives the concentration of uranium in the organic product of the extraction column and in the aqueous product of the solvent extraction system. The visual readouts of concentrations for process monitoring are updated every 2 min for both detection systems. Simultaneously, the concentration results are shipped to a remote computer that has been installed by Y-12 to demonstrate automatic control of the solvent extraction system based on input of near-real time process operation information. 8 refs., 13 figs., 4 tabs.

  10. Modeled atmospheric radon concentrations from uranium mines

    SciTech Connect

    Droppo, J.G.

    1985-04-01

    Uranium mining and milling operations result in the release of radon from numerous sources of various types and strengths. The US Environmental Protection Agency (EPA) under the Clean Air Act, is assessing the health impact of air emissions of radon from underground uranium mines. In this case, the radon emissions may impact workers and residents in the mine vicinity. To aid in this assessment, the EPA needs to know how mine releases can affect the radon concentrations at populated locations. To obtain this type of information, Pacific Northwest Laboratory used the radon emissions, release characteristics and local meterological conditions for a number of mines to model incremental radon concentrations. Long-term, average, incremental radon concentrations were computed based on the best available information on release rates, plume rise parameters, number and locations of vents, and local dispersion climatology. Calculations are made for a model mine, individual mines, and multiple mines. Our approach was to start with a general case and then consider specific cases for comparison. A model underground uranium mine was used to provide definition of the order of magnitude of typical impacts. Then computations were made for specific mines using the best mine-specific information available for each mine. These case study results are expressed as predicted incremental radon concentration contours plotted on maps with local population data from a previous study. Finally, the effect of possible overlap of radon releases from nearby mines was studied by calculating cumulative radon concentrations for multiple mines in a region with many mines. The dispersion model, modeling assumptions, data sources, computational procedures, and results are documented in this report. 7 refs., 27 figs., 18 tabs.

  11. Fungi outcompete bacteria under increased uranium concentration in culture media.

    PubMed

    Mumtaz, Saqib; Streten-Joyce, Claire; Parry, David L; McGuinness, Keith A; Lu, Ping; Gibb, Karen S

    2013-06-01

    As a key part of water management at the Ranger Uranium Mine (Northern Territory, Australia), stockpile (ore and waste) runoff water was applied to natural woodland on the mine lease in accordance with regulatory requirements. Consequently, the soil in these Land Application Areas (LAAs) presents a range of uranium concentrations. Soil samples were collected from LAAs with different concentrations of uranium and extracts were plated onto LB media containing no (0 ppm), low (3 ppm), medium (250 ppm), high (600 ppm) and very high (1500 ppm) uranium concentrations. These concentrations were similar to the range of measured uranium concentrations in the LAAs soils. Bacteria grew on all plates except for the very high uranium concentrations, where only fungi were recovered. Identifications based on bacterial 16S rRNA sequence analysis showed that the dominant cultivable bacteria belonged to the genus Bacillus. Members of the genera Paenibacillus, Lysinibacillus, Klebsiella, Microbacterium and Chryseobacterium were also isolated from the LAAs soil samples. Fungi were identified by sequence analysis of the intergenic spacer region, and members of the genera Aspergillus, Cryptococcus, Penicillium and Curvularia were dominant on plates with very high uranium concentrations. Members of the Paecilomyces and Alternaria were also present but in lower numbers. These findings indicate that fungi can tolerate very high concentrations of uranium and are more resistant than bacteria. Bacteria and fungi isolated at the Ranger LAAs from soils with high concentrations of uranium may have uranium binding capability and hence the potential for uranium bioremediation. PMID:23416228

  12. Fungi outcompete bacteria under increased uranium concentration in culture media.

    PubMed

    Mumtaz, Saqib; Streten-Joyce, Claire; Parry, David L; McGuinness, Keith A; Lu, Ping; Gibb, Karen S

    2013-06-01

    As a key part of water management at the Ranger Uranium Mine (Northern Territory, Australia), stockpile (ore and waste) runoff water was applied to natural woodland on the mine lease in accordance with regulatory requirements. Consequently, the soil in these Land Application Areas (LAAs) presents a range of uranium concentrations. Soil samples were collected from LAAs with different concentrations of uranium and extracts were plated onto LB media containing no (0 ppm), low (3 ppm), medium (250 ppm), high (600 ppm) and very high (1500 ppm) uranium concentrations. These concentrations were similar to the range of measured uranium concentrations in the LAAs soils. Bacteria grew on all plates except for the very high uranium concentrations, where only fungi were recovered. Identifications based on bacterial 16S rRNA sequence analysis showed that the dominant cultivable bacteria belonged to the genus Bacillus. Members of the genera Paenibacillus, Lysinibacillus, Klebsiella, Microbacterium and Chryseobacterium were also isolated from the LAAs soil samples. Fungi were identified by sequence analysis of the intergenic spacer region, and members of the genera Aspergillus, Cryptococcus, Penicillium and Curvularia were dominant on plates with very high uranium concentrations. Members of the Paecilomyces and Alternaria were also present but in lower numbers. These findings indicate that fungi can tolerate very high concentrations of uranium and are more resistant than bacteria. Bacteria and fungi isolated at the Ranger LAAs from soils with high concentrations of uranium may have uranium binding capability and hence the potential for uranium bioremediation.

  13. RECALIBRATION OF H CANYON ONLINE SPECTROPHOTOMETER AT EXTENDED URANIUM CONCENTRATION

    SciTech Connect

    Lascola, R

    2008-10-29

    The H Canyon online spectrophotometers are calibrated for measurement of the uranium and nitric acid concentrations of several tanks in the 2nd Uranium Cycle.[1] The spectrometers, flow cells, and prediction models are currently optimized for a process in which uranium concentrations are expected to range from 0-15 g/L and nitric acid concentrations from 0.05-6 M. However, an upcoming processing campaign will involve 'Super Kukla' material, which has a lower than usual enrichment of fissionable uranium. Total uranium concentrations will be higher, spanning approximately 0-30 g/L U, with no change in the nitric acid concentrations. The new processing conditions require the installation of new flow cells with shorter path lengths. As the process solutions have a higher uranium concentration, the shorter path length is required to decrease the absorptivity to values closer to the optimal range for the instrument. Also, new uranium and nitric acid prediction models are required to span the extended uranium concentration range. The models will be developed for the 17.5 and 15.4 tanks, for which nitric acid concentrations will not exceed 1 M. The restricted acid range compared to the original models is anticipated to reduce the measurement uncertainty for both uranium and nitric acid. The online spectrophotometers in H Canyon Second Uranium Cycle were modified to allow measurement of uranium and nitric acid for the Super Kukla processing campaign. The expected uranium concentrations, which are higher than those that have been recently processed, required new flow cells with one-third the optical path length of the existing cells. Also, new uranium and nitric acid calibrations were made. The estimated reading uncertainties (2{sigma}) for Tanks 15.4 and 17.5 are {approx}5% for uranium and {approx}25% for nitric acid.

  14. Can anthropogenic aerosol concentrations effect the snowfall rate?

    NASA Astrophysics Data System (ADS)

    Lohmann, U.; Zhang, J.; Pi, J.

    2003-04-01

    The mesoscale model GESIMA is used to simulate microphysical properties of Arctic clouds and their effect on radiation. Different case studies during the FIRE.ACE/SHEBA project show that GESIMA is able to simulate the cloud boundaries, ice and liquid water content and effective radii in good agreement with observations. For two different aerosol scenarios, the simulation results show that the anthropogenic aerosol can alter microphysical properties of Arctic clouds, and consequently modify surface precipitation. Borys et al. (2000) proposed that anthropogenically-induced decreases in cloud droplet size inhibit the riming process. On the contrary, we find that the accretion of snow crystals with cloud droplets is increased in the polluted cloud due to its higher cloud droplet number concentration. Instead the autoconversion rate of cloud droplets and accretion of drizzle by snow decreases caused by the shut-down of the collision-coalescence process in the polluted cloud. The amount of precipitation reaching the surface as snow depends crucially on the crystal shape. If aggregates are assumed, then a 10-fold increase in aerosol concentration leads to an increase in accumulated snow by 40% after 7 hours of simulation whereas the snow amount decreases by 30% when planar crystals are assumed because of the larger accretion efficiency of snow crystals with cloud droplets in case of aggregates. We will also perform climate model simulations to estimate the importance of this effect globally.

  15. Recent increase in Antarctic Peninsula ice core uranium concentrations

    NASA Astrophysics Data System (ADS)

    Potocki, Mariusz; Mayewski, Paul A.; Kurbatov, Andrei V.; Simões, Jefferson C.; Dixon, Daniel A.; Goodwin, Ian; Carleton, Andrew M.; Handley, Michael J.; Jaña, Ricardo; Korotkikh, Elena V.

    2016-09-01

    Understanding the distribution of airborne uranium is important because it can result in both chemical and radiological toxicity. Ice cores offer the most robust reconstruction of past atmospheric levels of toxic substances. Here we present the first sub-annually dated, continuously sampled ice core documenting change in U levels in the Southern Hemisphere. The ice core was recovered from the Detroit Plateau, northern Antarctic Peninsula, in 2007 by a joint Brazilian-Chilean-US team. It displays a significant increase in U concentration that coincides with reported mining activities in the Southern Hemisphere, notably Australia. Raw U concentrations in the Detroit Plateau ice core increased by as much as 102 between the 1980s and 2000s accompanied by increased variability in recent years. Decadal mean U concentrations increased by a factor of ∼3 from 1980 to 2007, reaching a mean of 205 pg/L from 2000 to 2007. The fact that other terrestrial source dust elements such as Ce, La, Pr, and Ti do not show a similar increase and that the increased U concentrations are enriched above natural crustal levels, supports an anthropogenic source for the U as opposed to a change in atmospheric circulation.

  16. Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture.

    PubMed

    Avelar, A C; Ferreira, W M; Pemberthy, D; Abad, E; Amaral, M A

    2016-05-01

    The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50pg WHO-TEQ g(-1)). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field. PMID:26901743

  17. Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture.

    PubMed

    Avelar, A C; Ferreira, W M; Pemberthy, D; Abad, E; Amaral, M A

    2016-05-01

    The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50pg WHO-TEQ g(-1)). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field.

  18. Paleozoic unconformities favorable for uranium concentration in northern Appalachian basin

    SciTech Connect

    Dennison, J.M.

    1986-05-01

    Unconformities can redistribute uranium from protore rock as ground water moves through poorly consolidated strata beneath the erosion surface, or later moves along the unconformity. Groundwater could migrate farther than in present-day lithified Paleozoic strata in the Appalachian basin, now locally deformed by the Taconic and Allegheny orogenies. Several paleoaquifer systems could have developed uranium geochemical cells. Sandstone mineralogy, occurrences of fluvial strata, and reduzate facies are important factors. Other possibilities include silcrete developed during desert exposure, and uranium concentrated in paleokarst. Thirteen unconformities are evaluated to determine favorable areas for uranium concentration. Cambrian Potsdam sandstone (New York) contains arkoses and possible silcretes just above crystalline basement. Unconformities involving beveled sandstones and possible fluvial strata include Cambrian Hardyston sandstone (New Jersey), Cambrian Potsdam Sandstone (New York), Ordovician Oswego and Juniata formations (Pennsylvania and New York), Silurian Medina Group (New York), and Silurian Vernon, High Falls, and Longwood formations (New York and New Jersey). Devonian Catskill Formation is beveled by Pennsylvanian strata (New York and Pennsylvania). The pre-Pennsylvanian unconformity also bevels Lower Mississippian Pocono, Knapp, and Waverly strata (Pennsylvania, New York, and Ohio), truncates Upper Mississippian Mauch Chunk Formation (Pennsylvania), and forms paleokarst on Mississippian Loyalhanna Limestone (Pennsylvania) and Maxville Limestone (Ohio). Strata associated with these unconformities contain several reports of uranium. Unconformities unfavorable for uranium concentration occur beneath the Middle Ordovician (New York), Middle Devonian (Ohio and New York), and Upper Devonian (Ohio and New York); these involve marine strata overlying marine strata and probably much submarine erosion.

  19. PROCESS FOR THE CONCENTRATION OF ORES CONTAINING GOLD AND URANIUM

    DOEpatents

    Gaudin, A.M.; Dasher, J.

    1958-06-10

    ABS>A process is described for concentrating certain low grade uranium and gold bearing ores, in which the gangue is mainly quartz. The production of the concentrate is accomplished by subjecting the crushed ore to a froth floatation process using a fatty acid as a collector in conjunction with a potassium amyl xanthate collector. Pine oil is used as the frothing agent.

  20. Concentrations and concentration factors of several anthropogenic and natural radionuclides in marine vertebrates and invertebrates. Final report

    SciTech Connect

    Noshkin, V.E.

    1985-07-17

    Literature is reviewed and summarized with regard to concentrations of several anthropogenic and natural radionuclides in biological organisms from marine environments. Reported concentration factors for these radionuclides in organisms are tabulated for marine fish and invertebrates from water masses affected by different source terms.

  1. Anthropogenic influences on groundwater arsenic concentrations in Bangladesh

    NASA Astrophysics Data System (ADS)

    Neumann, Rebecca B.; Ashfaque, Khandaker N.; Badruzzaman, A. B. M.; Ashraf Ali, M.; Shoemaker, Julie K.; Harvey, Charles F.

    2010-01-01

    The origin of dissolved arsenic in the Ganges Delta has puzzled researchers ever since the report of widespread arsenic poisoning two decades ago. Today, microbially mediated oxidation of organic carbon is thought to drive the geochemical transformations that release arsenic from sediments, but the source of the organic carbon that fuels these processes remains controversial. At a typical site in Bangladesh, where groundwater-irrigated rice fields and constructed ponds are the main sources of groundwater recharge, we combine hydrologic and biogeochemical analyses to trace the origin of contaminated groundwater. Incubation experiments indicate that recharge from ponds contains biologically degradable organic carbon, whereas recharge from rice fields contains mainly recalcitrant organic carbon. Chemical and isotopic indicators as well as groundwater simulations suggest that recharge from ponds carries this degradable organic carbon into the shallow aquifer, and that groundwater flow, drawn by irrigation pumping, transports pond water to the depth where dissolved arsenic concentrations are greatest. Results also indicate that arsenic concentrations are low in groundwater originating from rice fields. Furthermore, solute composition in arsenic-contaminated water is consistent with that predicted using geochemical models of pond-water-aquifer-sediment interactions. We therefore suggest that the construction of ponds has influenced aquifer biogeochemistry, and that patterns of arsenic contamination in the shallow aquifer result from variations in the source of water, and the complex three-dimensional patterns of groundwater flow.

  2. Uranium in runoff from the Gulf of Mexico distributive province: anomalous concentrations.

    PubMed

    Spalding, R F; Sackett, W M

    1972-02-11

    Uranium concentrations in North American rivers are higher than those reported 20 years ago. The increase is attributed to applications to agricultural land of larger amounts of phosphate fertilizer containing appreciable concentrations of uranium. Experiments showing a constant phosphorous-uranium ratio for various types of fertilizers and for the easily solubilized fraction of 0-46-0 fertilizers support this view.

  3. Radon concentration in houses over a closed Hungarian uranium mine.

    PubMed

    Somlai, János; Gorjánácz, Zorán; Várhegyi, András; Kovács, Tibor

    2006-08-31

    High radon concentration (average 410 kBq m-3) has been measured in a tunnel of a uranium mine, located 15-55 m below the village of Kovágószolos, Hungary. The mine was closed in 1997; the artificial ventilation of the tunnel was then terminated and recultivation works begun. In this paper, a study has been made as to whether the tunnel has an influence on the radon concentration of surface dwellings over the mining tunnel. At different distances from the surface projection of the mining tunnel, radon concentration, the gamma dose, radon exhalation and radon concentration of soil gas were measured. The average radon concentration in the dwellings was 483 Bq m-3. Significantly higher radon concentrations (average 667 Bq m-3) were measured in houses within +/-150 m from the surface projection of the mining tunnel +50 m, compared with the houses further than the 300-m belt (average 291 Bq m-3). The average radon concentration of the soil gas was 88.8 kBq m-3, the average radon exhalation was 71.4 Bq m-2 s-1 and higher values were measured over the passage as well. Frequent fissures crossing the passage and running up to the surface and the high radon concentration generated in the passage (average 410 kBq m-3) may influence the radon concentration of the houses over the mining tunnel.

  4. Safeguards on uranium ore concentrate? the impact of modern mining and milling process

    SciTech Connect

    Francis, Stephen

    2013-07-01

    Increased purity in uranium ore concentrate not only raises the question as to whether Safeguards should be applied to the entirety of uranium conversion facilities, but also as to whether some degree of coverage should be moved back to uranium ore concentrate production at uranium mining and milling facilities. This paper looks at uranium ore concentrate production across the globe and explores the extent to which increased purity is evident and the underlying reasons. Potential issues this increase in purity raises for IAEA's strategy on the Starting Point of Safeguards are also discussed.

  5. Reduction of Uranium(VI) to Uranium (IV) by Three Facultative Anaerobes at High Concentrations

    NASA Astrophysics Data System (ADS)

    Chabalala, Simphiwe; Chirwa, Evans M. N.

    2010-01-01

    Six bacteria species were isolated from a uranium mine in Limpopo, South Africa, and three facultative anaerobes reduced U(VI) to U(IV) and aided the removal of U(VI) from solution. The pure cultures showed a high reduction rate at pH 5 to 6 for concentrations 100-800 mg/L during the first 4 to 6 hours of incubation. A biological remediation process for removing U(VI) is desirable in the nuclear industry where more expensive environmentally non-friendly physical chemical processes have been used conventionally for decades.

  6. Radium and uranium concentrations in Georgia community water systems.

    PubMed

    Cline, W; Adamovitz, S; Blackman, C; Kahn, B

    1983-01-01

    The first cycle of statewide radionuclide concentration measurements of public drinking water supplies was completed in accord with the Federal and Georgia Safe Drinking Water Acts. The recommended pattern of analysis is initial screening for gross alpha-particle activity, followed by measuring 226Ra if the gross alpha-particle activity is above 5 pCi/l. and then measuring 228Ra if the 226Ra concentration is above 3 pCi/l; and uranium analysis if the gross alpha-particle activity exceeds 15 pCi/l. Surface water supplies for more than 100,000 persons are analyzed for 3H and 90Sr and screened for gross beta-particle activity, with additional analytical requirements if the latter is above 50 pCi/l. Specified supplies downstream for nuclear facilities are analyzed for 3H, 90Sr and 131I, and further analyses are required if the gross beta-particle activity is above 15 pCi/l. More thorough screening was applied for 1400 public water supplies in Georgia, of which about 90% use groundwater. Radium concentrations exceeded the maximum contaminant level (MCL) of 5 pCi/l. in 24 groundwater supplies, mostly due to elevated 226Ra. The gross alpha-particle activity minus uranium concentrations exceeded the 15 pCi/l. MCL in 3 additional samples. No MCL was exceeded in surface water. The S.D.s of analytical results estimated from replicate analyses were approximately twice those based on counting statistics, suggesting that screening levels should be lowered to assure detection of 226Ra at MCL values.

  7. Survey of Groundwater Concentrations of Uranium, Radon and other Constituents in Kleberg County, Texas

    NASA Astrophysics Data System (ADS)

    Gamboa, Y.; Fernandez, W.; Clapp, L. W.

    2011-12-01

    Uranium in the Southwest Texas coastal plains has been mined using in-situ recovery (ISR) for several decades. There is at least 36 closed and 3 active uranium mines in the region. Since the major source of drinking and irrigation water in the area is groundwater, the public is concerned about restoration of groundwater at uranium mining sites to baseline levels to prevent contamination of private wells by migration of contaminants such as uranium, molybdenum, selenium, strontium, and arsenic. One objective of this study is to determine the quality of the groundwater around ISR mining sites. 50 private drinking water wells were tested in areas near the Kingsville Dome uranium mining in Kleberg County, Texas during 2010 and 2011, and the concentrations of parameters of interest (U, Th, Mo, As, Se, Sr, Ca, Mg, Na, K, Cl , SO42-, NO3-, Br-, F-, radon, thoron, alkalinity, pH, conductivity and temperature) were determined. The results to date have shown that 58% of the wells surveyed had uranium concentrations greater than 10 ppb, and 22% had uranium concentrations greater than the EPA drinking water standard of 30 ppb, including four wells with uranium concentrations between 160 and 771 ppb. There was no significant correlation between the measured uranium concentrations and either distance or direction from the mining site. The measured concentrations will be compared with data in the USGS National Uranium Resource Evaluation (NURE) database for groundwater samples collected in the late 1970s.

  8. Autigenic and Anthropogenic Uranium in the Marine Sediments of the Gulf of California in Front of Santa Rosalia Mining District

    NASA Astrophysics Data System (ADS)

    Choumiline, K.; Rodríguez-Figueroa, G.; Shumilin, E.; Sapozhnikov, D.

    2007-05-01

    To verify the possibilities of U enrichments in the marine sedimentary environment of the eastern sector of the central Gulf of Califoria (GC), eleven sediment cores were collected in front of the Santa Rosalia mining region, peninsula of Baja California. Uranium and some other trace element contents in sliced core layers, dried and homogenized, were determined using instrumental neutron activation analysis. Average total U contents in sediments of five cores collected in the open GC in front of Santa Rosalía at sites with water depths from 265 m to 1030 m and in the Guaymas Basin with 2019 m, ranged from 1.36±0.26 mg kg-1 (Guaymas Basin) to 9.31±3.03 mg kg-1 (SR63 core, depth 630 m). To distinguish non-lithogenic U from the lithogenic one, the normalization of total U contents to the concentrations of Sc in the samples was used. That because this element is a reliable indicator of crustal materials, mainly aluminosilicates in the marine sediments. The relative contribution of non-lithogenic (authigenic) U varied from 49.8±3 % (Guaymas Basin) to 84.2±8.2 % (SR62 core) of the total U content in the sediments of the open central GC. Surprisingly, in three sediment cores from the coastal zone adjacent to the town of Santa Rosalía in water depth range 3-6 m very high concentrations of total U were found, ranging from 54.2±7.3 mg kg-1 (SR4 core) to 110±13 mg kg-1 (SR2 core) and exceeding not only U average abundance in the earth´s crust (2.7 mg kg-1), but also its levels found for SR62 core, as well as those reported for natural enrichments of U in suboxic-anoxic environments, e.g. at Mexico and Peru margin sites (3.04 mg kg-1 - 24.54 mg kg-1, McManus et al., 2006). The relative contribution of non-lithogenic U in the sediments of these three anomalous cores varied from 97.2±0.4 % (SR4 core) to 98.80.2 % (SR1 and SR2 cores) of their total U content. The sediments were also depleted in organic C (0.05 % - 0.18 %), which is not typical for marine solid phases

  9. Determination of Uranium Metal Concentration in Irradiated Fuel Storage Basin Sludge Using Selective Dissolution

    SciTech Connect

    Delegard, Calvin H.; Sinkov, Sergey I.; Chenault, Jeffrey W.; Schmidt, Andrew J.; Welsh, Terri L.; Pool, Karl N.

    2014-03-01

    Uranium metal corroding in water-saturated sludges now held in the US Department of Energy Hanford Site K West irradiated fuel storage basin can create hazardous hydrogen atmospheres during handling, immobilization, or subsequent transport and storage. Knowledge of uranium metal concentration in sludge thus is essential to safe sludge management and process design, requiring an expeditious routine analytical method to detect uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of 30 wt% or higher total uranium concentrations.

  10. Uranium and thorium in urine of United States residents: Reference range concentrations

    SciTech Connect

    Ting, B.G.; Paschal, D.C.; Jarrett, J.M.; Pirkle, J.L.; Jackson, R.J.; Sampson, E.J.; Miller, D.T.; Caudill, S.P. )

    1999-07-01

    The authors measured uranium and thorium in urine of 500 US residents to establish reference range concentrations using a magnetic-sector inductively coupled argon plasma mass spectrometer (ICP-MS). They found uranium at detectable concentrations in 96.6% of the urine specimens and thorium in 39.6% of the specimens. The 95th percentile concentration for uranium was 34.5 ng/L (parts per trillion); concentrations ranged up to 4,080 ng/L. Thorium had a 95th percentile concentration of 3.09 ng/L; concentrations ranged up to 7.7 ng/L.

  11. Anthropogenic sulfate and organic aerosols, CCN, and cloud project concentration at a marine site

    SciTech Connect

    Novakao, T.; Rivera-Carpio, C.; Penner, J.E.; Rogers, C.F.

    1993-10-01

    The need to establish the relationships between the number concentration of cloud droplets, cloud condensation nuclei (CCN), and the mass concentrations of major aerosol species has been heightened by the results of recent modeling studies suggesting that anthropogenic sulfate and biomass smoke aerosols may cause a globally averaged climate forcing comparable in magnitude but opposite in sign to the forcing due to ``greenhouse`` gases. In this paper we present the results of measurements of nonseasalt (nss) sulfate and organic carbon mass concentrations and mass size distributions, CCN, and cloud droplet number concentrations obtained in 1991 and 1992 on El Yunque peak, Puerto Rico . This peak (18{degree}19N, 65{degree}45W; elevation 1000 m) is located the eastern end of the island, directly exposed to the ocean winds and frequently covered with clouds. Our results show that although CCN number concentrations (measured at 0.5% supersaturation) and nss sulfate mass concentrations are significantly correlated at this site, estimates based on measured mass size distributions of organic and sulfate aerosols indicate that the organic aerosols may account for the majority of CCN number concentrations. Droplet concentrations in the cumulus clouds do not show a discernible trend with nss sulfate mass concentrations. In stratocumulus clouds a small increase in droplet concentrations with nss sulfate mass concentrations was observed.

  12. Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition.

    PubMed

    Zaborska, Agata

    2014-08-15

    The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition ((206)Pb/(207)Pb and (208)Pb/(206)Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g(-1)) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63-147 μg g(-1)) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m(2)year(-1), while after WWII they reached 199 Pb m(2)year(-1). Highest (206)Pb/(207)Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest (206)Pb/(207)Pb ratios (∼1.165) were measured in the sediments deposited in 1970s-90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included.

  13. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes).

    PubMed

    Carlitz, Esther H D; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C; van Schaik, Carel P

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

  14. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes).

    PubMed

    Carlitz, Esther H D; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C; van Schaik, Carel P

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species.

  15. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes)

    PubMed Central

    Carlitz, Esther H. D.; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C.; van Schaik, Carel P.

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

  16. Effects of trans-Eurasian transport of anthropogenic pollutants on surface ozone concentrations over China

    NASA Astrophysics Data System (ADS)

    Liu, J.; Li, X.; Mauzerall, D. L.; Emmons, L. K.; Horowitz, L. W.; Guo, Y.; Tao, S.

    2015-12-01

    Due to a lack of industrialization in Western China, surface air there was, until recently, believed to be relatively unpolluted. However, recent measurements and modeling studies have found high levels of ozone (O3) there. Based on the state-of-the-science global chemical transport model MOZART-4, we identify the origin, pathway, and mechanism of trans-Eurasian transport of air pollutants to Western China in 2000. MOZART-4 generally simulates well the observed surface O3 over inland areas of China. Simulations find surface ozone concentrations over Western China on average to be about 10 ppbv higher than Eastern China. Using sensitivity studies as well as a fully-tagged approach, we find that anthropogenic emissions from all Eurasian regions except China contribute 10-15 ppbv surface O3 over Western China, superimposed upon a 35-40 ppbv natural background. Transport from European anthropogenic sources to Northwestern China results in 2-6 ppbv O3 enhancements in spring and summer. Indian anthropogenic sources strongly influence O3 over the Tibetan Plateau during the summer monsoon. Transport of O3 originating from emissions in the Middle East occasionally reach Western China and increase surface ozone there by about 1-4 ppbv. These influences are of similar magnitude as trans-Pacific and transatlantic transport of O3 and its precursors, indicating the significance of trans-Eurasian ozone transport in hemispheric transport of air pollution. Our study further indicates that mitigation of anthropogenic emissions from Europe, the Indian subcontinent, and the Middle East could benefit public health and agricultural productivity in Western China.

  17. 76 FR 48882 - Agency Information Collections Activities; Comment Request for Uranium Concentrations in Private...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-09

    ... U.S. Geological Survey Agency Information Collections Activities; Comment Request for Uranium... Collection 1028-NEW, Uranium concentrations in private wells in south-east New Hampshire, in the subject line... telephone (970) 226-9165; or schusterr@usgs.gov (e-mail). SUPPLEMENTARY INFORMATION: I. Abstract...

  18. Calculating Capstone Depleted Uranium Aerosol Concentrations from Beta Activity Measurements

    SciTech Connect

    Szrom, Fran; Falo, Gerald A.; Parkhurst, MaryAnn; Whicker, Jeffrey J.; Alberth, David P.

    2009-03-01

    Beta activity measurements were used as surrogate measurements of uranium mass in aerosol samples collected during the field testing phase of the Capstone Depleted Uranium (DU) Aerosol Study. These aerosol samples generated by the perforation of armored combat vehicles were used to characterize the depleted uranium (DU) source term for the subsequent human health risk assessment (HHRA) of Capstone aerosols. Establishing a calibration curve between beta activity measurements and uranium mass measurements is straightforward if the uranium isotopes are in equilibrium with their immediate short-lived, beta-emitting progeny. For DU samples collected during the Capstone study, it was determined that the equilibrium between the uranium isotopes and their immediate short lived, beta-emitting progeny had been disrupted when penetrators had perforated target vehicles. Adjustments were made to account for the disrupted equilibrium and for wall losses in the aerosol samplers. Correction factors for the disrupted equilibrium ranged from 0.16 to 1, and the wall loss correction factors ranged from 1 to 1.92.

  19. Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    SciTech Connect

    Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

    1980-06-01

    Water and sediment samples were collected and each water sample was analyzed for U, and each sediment sample was analyzed for 43 elements, including U and Th. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District. Uranium concentrations in sediment samples range from 1.14 to 220.70 ppM and have a median of 3.37 ppM and a mean of 4.03 ppM. Throughout the major uranium mining districts of the Powder River Basin, sediment samples with high uranium concentrations were collected from dry streams located near wells producing water samples with high uranium concentrations. High uranium concentrations were also found associated with the Lance Creek oil field where uranium mineralization is known in the White River formation. High uranium concentrations were also found in sediment samples in areas where uranium mineralization is not known. These samples are from dry streams in areas underlain by the White River formation, the Niobrara formation, and the Pierre, Carlisle, Belle Fourche, and Mowry shales.

  20. African Anthropogenic Combustion Emissions: Estimate of Regional Mortality Attributable to Fine Particle Concentrations in 2030

    NASA Astrophysics Data System (ADS)

    Liousse, C.; Roblou, L.; Assamoi, E.; Criqui, P.; Galy-Lacaux, C.; Rosset, R.

    2014-12-01

    Fossil fuel (traffic, industries) and biofuel (domestic fires) emissions of gases and particles in Africa are expected to significantly increase in the near future, particularly due to rapid growth of African cities and megacities. In this study, we will present the most recent developments of African combustion emission inventories, including African specificities. Indeed, a regional fossil fuel and biofuel inventory for gases and particulates described in Liousse et al. (2014) has been developed for Africa at a resolution of 0.25° x 0.25° for the years 2005 and 2030. For 2005, the original database of Junker and Liousse (2008) was used after modification for updated regional fuel consumption and emission factors. Two prospective inventories for 2030 are derived based on Prospective Outlook on Long-term Energy Systems (POLES) model (Criqui, 2001). The first is a reference scenario (2030ref) with no emission controls and the second is for a "clean" scenario (2030ccc*) including Kyoto policy and African specific emission control. This inventory predicts very large increases of pollutant emissions in 2030 (e.g. contributing to 50% of global anthropogenic organic particles), if no emission regulations are implemented. These inventories have been introduced in RegCM4 model. In this paper we will focus on aerosol modelled concentrations in 2005, 2030ref and 2030ccc*. Spatial distribution of aerosol concentrations will be presented with a zoom at a few urban and rural sites. Finally mortality rates (respiratory, cardiovascular) caused by anthropogenic PM2.5 increase from 2005 to 2030, calculated following Lelieveld et al. (2013), will be shown for each scenarios. To conclude, this paper will discuss the effectiveness of scenarios to reduce emissions, aerosol concentrations and mortality rates, underlining the need for further measurements scheduled in the frame of the new DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions) program.

  1. Assessment of sources for higher Uranium concentration in ground waters of the Central Tamilnadu, India

    NASA Astrophysics Data System (ADS)

    Adithya, V. S.; Chidambaram, S.; Tirumalesh, K.; Thivya, C.; Thilagavathi, R.; Prasanna, M. V.

    2016-03-01

    The uranium concentration in groundwater has attained greater importance considering the health effects in mankind. Groundwater being the major source of uranium; sampling and analysis of groundwater for the major cations and anions along with uranium has been carried out in hard rock aquifers of Madurai district. The sampling has been carried out in varied aquifers like, Charnockites, Hornblende Biotite Gneiss, Granites, Quartzites, Laterites and sandstone. The cation and anions showed the following order of dominance Na+>Ca2+>Mg2+>K+ and that of anions are HCO3 ->Cl->SO4 2-> NO3 ->PO4 3-. Higher concentration of uranium was found along the granitic aquifers and it varied along the groundwater table condition. Further it was identified that the mineral weathering was the predominant source of U in groundwater. Tritium studies also reveal the fact that the younger waters are more enriched in uranium than the older groundwater with longer residence time.

  2. Holocene Changes in Land Cover and Greenhouse-gas Concentrations: Rethinking Natural vs Anthropogenic Causation

    NASA Astrophysics Data System (ADS)

    Roberts, C.

    2008-12-01

    The Holocene has witnessed a switch from a nature-dominated to a human-dominated Earth system. Although globally-significant human impacts (wildfire, megafaunal extinctions) occurred during the late Pleistocene, it was the advent of agriculture that led to the progressive transformation of land cover, and which distinguishes the Holocene from previous interglacial periods. A wide array of data provide clear evidence of local-to-regional human disturbance from ~5 ka BP, in some cases earlier. There is more uncertainty about when the anthropogenic "footprint" became detectable at a global scale, and there has consequently been debate about how much of the pre-industrial increase in atmospheric greenhouse gas concentrations is attributable to human causation, linked to processes such as deforestation (CO2) and wet rice cultivation (CH4). Although there has been recent progress in developing quantitative methods for translating pollen data into palaeo-land cover, such as the REVEALS model of Sugita (Holocene 2007) coupled to GIS, this has yet to be widely applied to existing data bases, and most pollen-based land-use reconstructions remain qualitative or semi-quantitative. Lake trophic status, sediment flux / soil erosion, and microcharcoal records of biomass burning provide alternative proxies that integrate regional-scale landscape disturbance. These proxy data along with documentary sources imply that globally-significant changes in land cover occurred prior to ~250 BP which must have altered atmospheric greenhouse gas concentrations by this time. The polarised debate for and against early anthropogenic impact on global carbon cycling mirrors our industrial-era division between nature and society, both conceptually (e.g. Cartesian dualism) and on the ground (e.g. demarcating land between monoculture agriculture and wilderness). However, for the period before ~1750 AD, this likely represents a false dichotomy, because pre-industrial societies more often formed part

  3. Will atmospheric CO2 concentration continue to increase if anthropogenic CO2 emissions cease?

    NASA Astrophysics Data System (ADS)

    MacDougall, A. H.; Eby, M.; Weaver, A. J.

    2013-12-01

    If anthropogenic CO2 emissions were to suddenly cease, the evolution of the atmospheric CO2 concentration would depend on the magnitude and sign of natural carbon sources and sinks. Experiments using Earth system models indicate that overall carbon sinks would dominate. However, these models have typically neglected the permafrost carbon pool, which has the potential to introduce an additional terrestrial source of carbon to the atmosphere. Here we use the University of Victoria Earth System Climate Model, which has recently been expanded to include permafrost carbon stocks and exchanges with the atmosphere. In a scenario of zeroed CO2 and sulphate aerosol emissions, we assess whether the warming induced by specified constant concentrations of non-CO2 greenhouse gases could slow the CO2 decline following zero emissions, or even reverse this trend and cause CO2 to increase over time. We find that a radiative forcing from non-CO2 gases of approximately 0.6 W m-2 results in a near balance of CO2 emissions from the terrestrial biosphere and uptake of CO2 by the oceans, resulting in near-constant atmospheric CO2 concentrations for at least a century after emissions are eliminated. At higher values of non-CO2 radiative forcing, CO2 concentrations increase over time, regardless of when emissions cease during the 21st century. Given that the present-day radiative forcing from non-CO2 greenhouse gases is about 0.95 W m-2, our results suggest that if we were to eliminate all CO2 and aerosols emissions without also decreasing non-CO2 greenhouse gas emissions, CO2 levels would increase over time, resulting in a small increase in climate warming. The sudden and total cessation of anthropogenic CO2 emissions is an unlikely future scenario. However, such cessation experiments provide a useful method for evaluating the relative strength of the terrestrial and oceanic carbon cycle feedbacks in the presence of forcing from non-CO2 greenhouse gasses.

  4. Radium and uranium concentrations and associated hydrogeochemistry in ground water in southwestern Pueblo County, Colorado

    USGS Publications Warehouse

    Felmlee, J. Karen; Cadigan, Robert Allen

    1979-01-01

    Radium and uranium concentrations in water from 37 wells tapping the aquifer system of the Dakota Sandstone and Purgatoire Formation in southwestern Pueblo County, Colorado, have a wide range of values and define several areas of high radioactivity in the ground water. Radium ranges from 0.3 to 420 picocuries per liter and has a median value of 8.8, and uranium ranges from 0.02 to 180 micrograms per liter and has a median value of 2.4. Radon concentrations, measured in 32 of the 37 wells, range from less than 100 picocuries per liter to as much as 27,000 and have a median value of 580. Relationships among the radioactive elements and 28 other geochemical parameters were studied by using correlation coefficients and R-mode factor analysis. Five factor groups were determined to represent major influences on water chemistry: (1) short-term solution reactions, (2) oxidation reactions, (3) hydrolysis reactions, (4) uranium distribution, and (5) long-term solution reactions. Uranium concentrations are most strongly influenced by oxidation reactions but also are affected by solution reactions and distribution of uranium in the rocks of the aquifer system. Radon and radium concentrations are mostly controlled by uranium distribution; radium also shows a moderate negative relationship with oxidation. To explain the statistical and spatial relationships among the parameters, a model was developed involving the selective leaching of uranium-bearing phases and metal sulfides which occur in discontinuous zones in sandstone and shale. When reducing conditions prevail, uranium is immobile, but radium can be taken into solution. When faults and associated fractured rocks allow oxidizing conditions to dominate, uranium can be taken into solution; radium can also be taken into solution, or it may become immobilized by coprecipitation with iron and manganese oxides or with barite. Several areas within the study area are discussed in terms of the model.

  5. Uranium migration through intact sandstone: effect of pollutant concentration and the reversibility of uptake

    NASA Astrophysics Data System (ADS)

    Sims, R.; Lawless, T. A.; Alexander, J. L.; Bennett, D. G.; Read, D.

    1996-02-01

    A series of core flood experiments has been performed to investigate the migration behaviour of uranium under rigidly controlled conditions. Intact sandstone cores, pre-equilibrated with synthetic groundwater, were flooded with uranium solutions at varying concentrations and the transport process monitored as a function of pH, tracer concentration and the concentration of a competing ion, cadmium. In each case a substantial amount of uranium was retained by the core, implying a strong interaction with the rock matrix. The adsorption process was found to be highly concentration dependent; however, such that the finite retention capacity of an intact core can be exhausted within a relatively short time. The reversibility of uptake was studied by attempting to displace adsorbed uranium by injected cadmium and flushing with brine. Most of the uranium was readily recoverable but a small percentage is released very slowly on flushing, suggesting conversion to a more stable form. Prior to performing each experiment a simulation was carried out using a one-dimensional coupled chemical transport code, encompassing a thermodynamic description of the electrical double layer. The model was successful in predicting a priori the dominant trends in the uranium migration behaviour which may aid in model developments for more complex geochemical regimes than those studied here.

  6. The mean concentration of uranium in drinking water, urine, and hair of the occupationally unexposed Finnish working population.

    PubMed

    Muikku, Maarit; Puhakainen, Marketta; Heikkinen, Tarja; Ilus, Taina

    2009-06-01

    Uranium concentrations in the household water, urine, and hair of the occupationally unexposed Finnish working population were determined using inductively coupled plasma mass spectrometry (ICP-MS). The age of the randomly selected participants ranged from 18 to 66 y. The mean concentrations of uranium in water, urine, and hair were 1.25 microg L(-1), 0.016 microg L(-1), and 0.216 microg g(-1), respectively. The mean uranium concentration in hair of the Finnish working population was from 3- to 15-fold higher than the values reported in the literature, while the mean uranium concentration in urine was similar to those measured elsewhere in Europe. The observed large variation in the uranium concentrations in hair and urine can be explained by the variation in the uranium concentration in drinking water. Exceptionally high concentrations have been measured in private drilled wells in the granite areas of Southern Finland.

  7. Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    SciTech Connect

    Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

    1980-06-01

    During the summer and fall of 1977, 533 water and 1226 sediment samples were collected from 1740 locations within the 18,000 km/sup 2/ area of the Newcastle quadrangle, Wyoming. Water samples were collected from wells and springs; sediment samples were collected from stream channels and from springs. Each water sample was analyzed for uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations (>20 ppB) generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District.

  8. Uranium concentration and distribution in six peridotite inclusions of probable mantle origin

    USGS Publications Warehouse

    Haines, E.L.; Zartman, R.E.

    1973-01-01

    Fission-track activation was used to investigate uranium concentration and distribution in peridotite inclusions in alkali basalt from six localities. Whole-rock uranium concentrations range from 24 to 82 ng/g (1 ng = 10-9 g). Most of the uranium is uniformly distributed in the major silicate phases - olivine, orthopyroxene, and clinopyroxene. Chromian spinels may be classified into two groups on the basis of their uranium content, having either less than 10 ng/g or 100-150 ng/g U. In one sample accessory hydrous phases, phlogopite and hornblende, contain 130 and 300 ng/g U, respectively. The contact between the inclusion and the host basalt is usually quite sharp. Glassy or microcrystalline veinlets found in some samples contain more than 1??g/g (1 ??g = 10-6 g). Very little uranium is associated with microcrystals of apatite. Our results agree with some earlier investigators, who have concluded that suboceanic peridotites contain too little uranium to account for normal oceanic heat flow by conduction alone. ?? 1973.

  9. Uranium concentration and distribution in six peridotite inclusions of probable mantle origin

    NASA Technical Reports Server (NTRS)

    Haines, E. L.; Zartman, R. E.

    1973-01-01

    Fission-track activation was used to investigate uranium concentration and distribution in peridotite inclusions in alkali basalt from six localities. Whole-rock uranium concentrations range from 24 to 82 ng/g. Most of the uranium is uniformly distributed in the major silicate phases - olivine, orthopyroxene, and clinopyroxene. Chromian spinels may be classified into two groups on the basis of their uranium content - those which have less than 10 ng/g and those which have 100 to 150 ng/g U. In one sample accessory hydrous phases, phlogopite and hornblende, contain 130 and 300 ng/g U, respectively. The contact between the inclusion and the host basalt is usually quite sharp. Glassy or microcrystalline veinlets found in some samples contain more than 1 microgram/g. Very little uranium is associated with microcrystals of apatite. These results agree with some earlier investigators, who have concluded that suboceanic peridotites contain too little uranium to account for normal oceanic heat flow by conduction alone.

  10. Biological processes for concentrating trace elements from uranium mine waters. Technical completion report

    SciTech Connect

    Brierley, C.L.; Brierley, J.A.

    1981-12-01

    Waste water from uranium mines in the Ambrosia Lake district near Grants, New Mexico, USA, contains uranium, selenium, radium and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters. Some of the conclusions derived from this study are: (1) The concentrations of soluble uranium, selenium and molybdenum were not diminished in the mine waters by passage through the series of impoundments which constituted the mine water treatment facility. Uranium concentrations were reduced but this was due to passage of the water through an ion exchange column. (2) The particulate concentrations of the mine water were reduced at least ten-fold by passage of the waters through the impoundments. (3) The sediments were anoxic and enriched in uranium, molybdenum and selenium. The deposition of particulates and the formation of insoluble compounds were proposed as mechanisms for sediment enrichment. (4) The predominant algae of the treatment ponds were the filamentous Spirogyra and Oscillatoria, and the benthic alga, Chara. (5) Adsorptive processes resulted in the accumulation of metals in the algae cells. (6) Stimulation of sulfate reduction by the bacteria resulted in retention of molybdenum, selenium, and uranium in sediments. 1 figure, 16 tables.

  11. Investigating Uranium Concentrations in Groundwaters in the State of Idaho Using Kinetic Phosphorescence Analysis and Inductively Coupled Plasma Mass Spectrometry.

    PubMed

    Tkavadze, Levan; Dunker, Roy E; Brey, Richard R; Dudgeon, John

    2016-11-01

    The determination of uranium concentrations in natural water samples is of great interest due to the environmental consequences of this radionuclide. In this study, 380 groundwater samples from various locations within the state of Idaho were analyzed using two different techniques. The first method was Kinetic Phosphorescence Analysis (KPA), which gives the total uranium concentrations in water samples. The second analysis method was inductively coupled plasma mass spectrometry (ICP- MS). This method determines the total uranium concentration as well as the separate isotope concentrations of uranium. The U/U isotopic ratio was also measured for each sample to confirm that there was no depleted or enriched uranium present. The results were compared and mapped separately from each other. The study also found that in some areas of the state, natural uranium concentrations are relatively high. PMID:27682901

  12. Determination of uranium concentration in ground water samples of Northern Greece

    NASA Astrophysics Data System (ADS)

    Samaropoulos, I.; Efstathiou, M.; Pashalidis, I.; Ioannidou, A.

    2012-04-01

    The activity concentration of 238U and 234U has been determined in groundwater samples of hot springs and deep wells from the region of Northern Greece. The analysis was performed by alpha spectroscopy after pre-concentration and separation of uranium by cation exchange (Chelex 100 resin) and finally its electro-deposition on stainless steel discs. The uranium concentration in deep wells and springs varies strongly between 0.15 and 7.66 μg l-1. Generally the springs present higher uranium concentration than the deep wells, except of the Apol-lonia spring, which has shown the lowest value of 0.15 mg l-1. 238U and 234U activity concentration ranged between 1.8-95.3 mBq l-1 and 1.7-160.1 mBq l-1, respectively. The obtained isotopic ratio 234U/238U varies between 0.95 and 1.74 which means that the two isotopes are not in radioactive equilibrium. The highest 234U/238U activity ratio values correspond to the Langada springs, indicating most probably old-type waters. On the other hand, ground waters from wells with relatively low uranium activity concentration and low 234U/238U isotopic ratios, point to the presence of younger waters with a stronger contribution of a local recharge component to the groundwater.

  13. Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India.

    PubMed

    Balakrishna, K; Kumar, Itta Arun; Srinikethan, G; Mugeraya, Gopal

    2006-11-01

    Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO(2) emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans.

  14. Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India.

    PubMed

    Balakrishna, K; Kumar, Itta Arun; Srinikethan, G; Mugeraya, Gopal

    2006-11-01

    Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO(2) emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. PMID:16738757

  15. Concentrating anthropogenic disturbance to balance ecological and economic values: applications to forest management.

    PubMed

    Tittler, Rebecca; Messier, Christian; Fall, Andrew

    2012-06-01

    To maintain healthy ecosystems, natural-disturbance-based management aims to minimize differences between unmanaged and managed landscapes. Two related approaches may help accomplish this goal, either applied together or in isolation: (1) concentrating anthropogenic disturbance through zoning (with protected areas and intensive management); and (2) emulating natural disturbances. The purpose of this paper is to examine the effects of these two approaches, applied both in isolation and in combination, on the structure of the forest landscape. To do so, we use a spatially explicit landscape simulation model on a large fire-dominated landscape in eastern Canada. Specifically, we examine the effects of (1) increasing the maximum size of logged stands (cutblocks) to better emulate the full range of fire sizes in a fire-dominated landscape, (2) increasing protected areas, and (3) adding aggregated or dispersed intensive wood production areas to the landscape in addition to protected areas (triad management). We focus on maximizing the amount and minimizing the fragmentation of old-growth forest and on reducing road construction. Increasing maximum cutblock size and adding protected areas led to reduced road construction, while the latter also resulted in less fragmentation and more old growth. Although protected areas led to reduced harvest volume, the addition of an intensive production zone (triad management) counterbalanced this loss and resulted in more old growth than equivalent scenarios with protected areas but no intensive production zone. However, we found no differences between aggregated and dispersed intensive wood production. Our results imply that differences between unmanaged and managed landscapes can be reduced by concentrating logging efforts through a combination of protected areas and intensive wood production, and by creating some larger cutblocks. We conclude that the forest industry and regulators should therefore seek to increase protected areas

  16. Evaluation of the anthropogenic radionuclide concentrations in sediments and fauna collected in the Beaufort Sea and northern Alaska

    SciTech Connect

    Efurd, D.W.; Miller, G.G.; Rokop, D.J.

    1997-07-01

    This study was performed to establish a quality controlled data set about the levels of radio nuclide activity in the environment and in selected biota in the U.S. Arctic. Sediment and biota samples were collected by the National Oceanic and Atmospheric Administration (NOAA), the National Biological Service, and the North Slope Borough`s Department of Wildlife Management to determine the impact of anthropogenic radionuclides in the Arctic. The results summarized in this report are derived from samples collected in northwest Alaska with emphasis on species harvested for subsistence in Barrow, Alaska. Samples were analyzed for the anthropogenic radionuclides {sup 90}Sr, {sup 137}Cs, {sup 238}Pu, {sup 239}Pu, {sup 240}Pu and {sup 241}Am. The naturally occurring radionuclides {sup 40}K, {sup 212}Pb and {sup 214}Pb were also measured. One goal of this study was to determine the amounts of anthropogenic radionuclides present in the Beaufort Sea. Sediment samples were isotopically fingerprinted to determine the sources of radio nuclide activities. Biota samples of subsistence and ecological value were analyzed to search for evidence of bio-accumulation of radionuclides and to determine the radiation exposures associated with subsistence living in northern Alaska. The anthropogenic radio nuclide content of sediments collected in the Beaufort Sea was predominantly the result of the deposition of global fallout. No other sources of anthropogenic radionuclides could be conclusively identified in the sediments. The anthropogenic radio nuclide concentrations in fish, birds and mammals were very low. Assuming that ingestion of food is an important pathway leading to human contact with radioactive contaminants and given the dietary patterns in coastal Arctic communities, it can be surmised that marine food chains are presently not significantly affected.

  17. An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

    SciTech Connect

    McGinnis, Brent

    2014-04-01

    Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

  18. Concentration of uranium and plutonium in unsaturated spent fuel tests.

    SciTech Connect

    Finn, P. A.

    1998-04-15

    Commercial spent fuel is being tested under oxidizing conditions at 90 C in drip tests with simulated groundwater to evaluate its long-term performance in a potential repository at Yucca Mountain [1-4]. The tests allow us to monitor the dissolution behavior of the spent fuel matrix and the release rates of individual radionuclides. This paper reports the U and Pu concentrations in the leachates of drip tests during 3.7 years of reaction. Changes in these concentrations are correlated with changes in the measured pH and the appearance of alteration products on the fuel surface. Although there is little thermodynamic information at 90 C for either uranyl or plutonium compounds, some data are available at 25 C [5-8]. The literature data for the U and Pu solubilities of U and Pu compounds were compared to the U and Pu concentrations in the leachates. We also compare Wilson's [9] U and Pu concentrations in semi-static tests at 85 C on spent fuel with our results.

  19. Hydrocarbon-mediated gold and uranium concentration in the Witwatersrand Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Fuchs, Sebastian; Williams-Jones, Anthony; Schumann, Dirk; Couillard, Martin; Murray, Andrew

    2016-04-01

    The Witwatersrand deposits in South Africa represent the largest repository of gold in the World and a major resource of uranium. The genesis of the gold and uranium ores in the quartz-pebble conglomerates (reefs), however, is still a matter of considerable discussion. Opinion has been divided over whether they represent paleo-placers that have been partly remobilised by hydrothermal fluids or if the mineralisation is entirely hydrothermal in origin. In addition, recently published models have proposed a syngenetic origin for the gold involving bacterially-mediated precipitation from meteoric water and shallow seawater. An important feature of the gold and uranium mineralisation in the reefs is the strong spatial association with organic matter. In some reefs, up to 70% of the gold and almost the entire uranium resource is spatially associated with pyrobitumen seams, suggesting a genetic relationship of the gold-uranium mineralisation with hydrocarbons. Here we report results of a study of the Carbon Leader Reef, using high-resolution scanning and transmission electron microscopy (SEM / TEM) and LA-ICP-MS that provide new insights into the role of hydrocarbons in the concentration of the gold and uranium. A detailed examination revealed gold monocrystals containing numerous rounded or elliptical inclusions filled with pyrobitumen. We interpret these inclusions to record the crystallisation of the gold around droplets of a hydrocarbon liquid that migrated through the Witwatersrand basin, and was converted to pyrobitumen by being heated. We propose that the gold was transported in a hydrothermal fluid as a bisulphide complex and that this fluid mixed with the hydrocarbon liquid to form a water-oil emulsion. The interaction between the two fluids caused a sharp reduction in fO2 at the water-oil interface, which destabilised the gold-bisulphide complexes, causing gold monocrystals to precipitate around the oil droplets. In contrast to the gold, uraninite, the principal

  20. Determination of the concentration and isotopic composition of uranium in environmental air filters

    SciTech Connect

    Russ, G.P. III; Bazan, J.M.

    1994-08-26

    For many years, Lawrence Livermore National Laboratory has collected monthly air-particulate filter samples from a variety of environmental monitoring stations on and off site. Historically the concentration and isotopic composition of uranium collected on these filters was determined by isotope dilution using a {sup 233}U spike and thermal ionization mass spectrometry (TIMS). For samples containing as little as 10 nanograms of uranium, ICP-MS is now used to make these measurements to the required level of precision, about 5% in the measured 235/238 and 233/238. Unless particular care is taken to control bias in the mass filter, variable mass bias limits accuracy to a few percent. Measurements of the minor isotopes 236 (if present) and 234 are also possible and provide useful information for identifying the source of the uranium. The advantage of ICP-MS is in rapid analysis, {approximately}12 minutes of instrument time per sample.

  1. Low-concentration uranium enters the HepG2 cell nucleus rapidly and induces cell stress response.

    PubMed

    Guéguen, Yann; Suhard, David; Poisson, Clémentine; Manens, Line; Elie, Christelle; Landon, Géraldine; Bouvier-Capely, Céline; Rouas, Caroline; Benderitter, Marc; Tessier, Christine

    2015-12-25

    This study aimed to compare the cell stress effects of low and high uranium concentrations and relate them to its localization, precipitate formation, and exposure time. The time-course analysis shows that uranium appears in cell nuclei as a soluble form within 5 min of exposure, and quickly induces expression of antioxidant and DNA repair genes. On the other hand, precipitate formations began at the very beginning of exposure at the 300-μM concentration, but took longer to appear at lower concentrations. Adaptive response might occur at low concentrations but are overwhelmed at high concentrations, especially when uranium precipitates are abundant.

  2. Assessing the relation between anthropogenic pressure and PAH concentrations in surface water in the Seine River basin using multivariate analysis.

    PubMed

    Uher, Emmanuelle; Mirande-Bret, Cécile; Gourlay-Francé, Catherine

    2016-07-01

    Understanding the relation between polycyclic aromatic hydrocarbons (PAHs) in freshwater and anthropogenic pressure is fundamental to finding a solution to reduce the presence of PAHs in water, and thus their potential impact on aquatic life. In this paper we propose to gain greater insight into the variability, sources and partitioning of PAHs in labile (or freely dissolved=not associated to the organic matter), dissolved and particulate phases in freshwater. This study was conducted using land use data as a marker of anthropogenic pressure and coupling it with chemical measurements. This study was conducted on 30 sites in the Seine River basin, which is subjected to a strong human impact and exhibits a wide range of land uses. Half of the sites were studied twice. Labile PAHs were measured by semi-permeable membrane devices (SPMDs), and dissolved and particulate phases by grab samples. Partial least squares regressions were performed between chemical measurements and data of anthropogenic pressure. The results indicate different sources for the dissolved phase and particles. Dissolved and labile phases were more related to the population density of the watershed, while particles were more related to a local pressure. Season and land use data are necessary information to correctly interpret and compare PAH concentrations from different sites. Furthermore, the whole data set of the 45 field deployments comprising labile, dissolved, total and particulate PAH concentrations as well as the physico-chemical parameters is available in the supplementary information. PMID:27037876

  3. Predictive analysis of shaft station radon concentrations in underground uranium mine: A case study.

    PubMed

    Zhao, Guoyan; Hong, Changshou; Li, Xiangyang; Lin, Chunping; Hu, Penghua

    2016-07-01

    This paper presented a method for predicting shaft station radon concentrations in a uranium mine of China through theoretical analysis, mathematical derivation and Monte-Carlo simulation. Based upon the queuing model for tramcars, the average waiting time of tramcars and average number of waiting tramcars were determined, which were further used in developing the predictive model for calculating shaft station radon concentrations. The results exhibit that the extent of variation of shaft station radon concentration in the case study mine is not significantly affected by the queuing process of tramcars, and is always within the allowable limit of 200 Bq m(-3). Thus, the empirical limit of 100,000 T annual ore-hoisting yields has no value in ensuring radiation safety for this mine. Moreover, the developed model has been validated and proved useful in assessing shaft station radon levels for any uranium mine with similar situations.

  4. Geostatistical site characterization of hydraulic head and uranium concentration in groundwater

    SciTech Connect

    Buxton, B.E.; Wells, D.E.; Pate, A.D.

    1996-12-31

    The first case study presented in this paper describes an assessment of the spatial distribution and temporal changes in hydraulic head pressure in the groundwater beneath a retired federal government uranium processing facility. Analysis of the hydraulic heads involved ordinary kriging which was found to be a better mapping method than such alternatives as inverse-distance weighting, mainly because kriging provides measures of estimation uncertainty. The objective of this kriging was to provide estimated steady-state head values for use in calibrating a groundwater flow model for the site. In the second case study, the spatial distribution of potential uranium contamination in the aquifer was assessed with lognormal kriging. Uranium measurements for this analysis were available at roughly three-month intervals across a four-year time period. The objective of the analysis was to assess where the uranium concentrations were highest. A second objective, not addressed in this paper, was to determine if the concentrations were changing significantly during the four-year time period.

  5. Application of neodymium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    PubMed

    Krajkó, Judit; Varga, Zsolt; Yalcintas, Ezgi; Wallenius, Maria; Mayer, Klaus

    2014-11-01

    A novel procedure has been developed for the measurement of (143)Nd/(144)Nd isotope ratio in various uranium-bearing materials, such as uranium ores and ore concentrates (UOC) in order to evaluate the usefulness and applicability of variations of (143)Nd/(144)Nd isotope ratio for provenance assessment in nuclear forensics. Neodymium was separated and pre-concentrated by extraction chromatography and then the isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method was validated by the measurement of standard reference materials (La Jolla, JB-2 and BCR-2) and the applicability of the procedure was demonstrated by the analysis of uranium samples of world-wide origin. The investigated samples show distinct (143)Nd/(144)Nd ratio depending on the ore type, deposit age and Sm/Nd ratio. Together with other characteristics of the material in question, the Nd isotope ratio is a promising signature for nuclear forensics and suggests being indicative of the source material, the uranium ore.

  6. [Regularities of lateral distribution of uranium and thorium decay series radionuclides in the anthropogenically changed soils from the area of radium production waste storage].

    PubMed

    Evseeva, T I; Belykh, E S; Maĭstrenko, T A; Geras'kin, S A; Taskaev, A I; Vakhrusheva, O M

    2012-01-01

    Cartographical investigations of the territory of radium production waste storage has shown some changes in lateral differentiation of radionuclides of uranium and thorium decay series to occur during 27 years (1981-2008). Those changes are caused mostly by flat denudation typical for fluvial terrace. At present radionuclides of uranium and thorium decay series are concentrated mostly in flood lands and relief depressions. At the same time, decrease in the radionuclide activity concentration in 0-20 cm soil layer is observed with changes in lateral distribution. Total stocks of 226Ra, 210Pb and 210Po within catena soils studied in the northern and southern parts of the waste storage decreased 3-6 times, 238U - 2 times, and did not significantly change in case of 232Th during 27 years. Nonetheless, most of the samples studied are referred to radioactive waste both according to Russian standards (SPORO-2002) and IAEA safety norms (IAEA, 2004).

  7. [Regularities of lateral distribution of uranium and thorium decay series radionuclides in the anthropogenically changed soils from the area of radium production waste storage].

    PubMed

    Evseeva, T I; Belykh, E S; Maĭstrenko, T A; Geras'kin, S A; Taskaev, A I; Vakhrusheva, O M

    2012-01-01

    Cartographical investigations of the territory of radium production waste storage has shown some changes in lateral differentiation of radionuclides of uranium and thorium decay series to occur during 27 years (1981-2008). Those changes are caused mostly by flat denudation typical for fluvial terrace. At present radionuclides of uranium and thorium decay series are concentrated mostly in flood lands and relief depressions. At the same time, decrease in the radionuclide activity concentration in 0-20 cm soil layer is observed with changes in lateral distribution. Total stocks of 226Ra, 210Pb and 210Po within catena soils studied in the northern and southern parts of the waste storage decreased 3-6 times, 238U - 2 times, and did not significantly change in case of 232Th during 27 years. Nonetheless, most of the samples studied are referred to radioactive waste both according to Russian standards (SPORO-2002) and IAEA safety norms (IAEA, 2004). PMID:22568020

  8. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    PubMed

    Dafforn, Katherine A; Kelaher, Brendan P; Simpson, Stuart L; Coleman, Melinda A; Hutchings, Pat A; Clark, Graeme F; Knott, Nathan A; Doblin, Martina A; Johnston, Emma L

    2013-01-01

    Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic modification.

  9. Polychaete Richness and Abundance Enhanced in Anthropogenically Modified Estuaries Despite High Concentrations of Toxic Contaminants

    PubMed Central

    Dafforn, Katherine A.; Kelaher, Brendan P.; Simpson, Stuart L.; Coleman, Melinda A.; Hutchings, Pat A.; Clark, Graeme F.; Knott, Nathan A.; Doblin, Martina A.; Johnston, Emma L.

    2013-01-01

    Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a ‘positive’ response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively ‘pristine’ estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  10. Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

    SciTech Connect

    Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Lagos, Leonel; Tansel, Berrin

    2013-09-05

    ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperatures of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.

  11. Uranium hydrogeochemical and stream sediment reconnasissance of the Trinidad NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

    SciTech Connect

    Shannon, S.S. Jr.

    1980-05-01

    Uranium and other elemental data resulting from the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Trinidad National Topographic Map Series (NTMS) quadrangle, Colorado, by the Los Alamos Scientific Laboratory (LASL) are reported herein. This study was conducted as part of the United States Department of Energy's National Uranium Resource Evaluation (NURE), which is designed to provide improved estimates of the availability and economics of nuclear fuel resources and to make available to industry information for use in exploration and development of uranium resources. The HSSR data will ultimately be integrated with other NURE data (e.g., airborne radiometric surveys and geological investigations) to complete the entire NURE program. This report is a supplement to the HSSR uranium evaluation report for the Trinidad quadrange (Morris et al, 1978), which presented the field and uranium data for the 1060 water and 1240 sediment samples collected from 1768 locations in the quadrangle. The earlier report contains an evaluation of the uranium concentrations of the samples as well as descriptions of the geology, hydrology, climate, and uranium occurrences of the quadrange. This supplement presents the sediment field and uranium data again and the analyses of 42 other elements in the sediments. All uranium samples were redetermined by delayed-neutron counting (DNC) when the sediment samples were analyzed for 31 elements by neutron activation. For 99.6% of the sediment samples analyzed, the differences between the uranium contents first determined (Morris et al, 1978) and the analyses reported herein are less than 10%.

  12. Evaluation of Background Concentrations of Contaminants in an Unusual Desert Arroyo Near a Uranium Mill Tailings Disposal Cell - 12260

    SciTech Connect

    Bush, Richard P.; Morrison, Stan J.

    2012-07-01

    The U.S. Department of Energy (DOE) Office of Legacy Management (LM) manages 27 sites that have groundwater containing uranium concentrations above background levels. The distal portions of the plumes merge into background groundwater that can have 50 μg/L or more uranium. Distinguishing background from site-related uranium is often problematic, but it is critical to determining if remediation is warranted, establishing appropriate remediation goals, and evaluating disposal cell performance. In particular, groundwater at disposal cells located on the upper Cretaceous Mancos Shale may have relatively high background concentrations of uranium. Elevated concentrations of nitrate, selenium, and sulfate accompany the uranium. LM used geologic analogs and uranium isotopic signatures to distinguish background groundwater from groundwater contaminated by a former uranium processing site. The same suite of contaminants is present in groundwater near former uranium processing sites and in groundwater seeps emanating from the Mancos Shale over a broad area. The concentrations of these contaminants in Many Devils Wash, located near LM's Shiprock disposal cell, are similar to those in samples collected from many Mancos seeps, including two analog sites that are 8 to 11 km from the disposal cell. Samples collected from Many Devils Wash and the analog sites have high AR values (about 2.0)-in contrast, groundwater samples collected near the tailings disposal cell have AR values near 1.0. These chemical signatures raise questions about the origin of the contamination seeping into Many Devils Wash. (authors)

  13. Radiological Modeling for Determination of Derived Concentration Levels of an Area with Uranium Residual Material - 13533

    SciTech Connect

    Perez-Sanchez, Danyl

    2013-07-01

    As a result of a pilot project developed at the old Spanish 'Junta de Energia Nuclear' to extract uranium from ores, tailings materials were generated. Most of these residual materials were sent back to different uranium mines, but a small amount of it was mixed with conventional building materials and deposited near the old plant until the surrounding ground was flattened. The affected land is included in an area under institutional control and used as recreational area. At the time of processing, uranium isotopes were separated but other radionuclides of the uranium decay series as Th-230, Ra-226 and daughters remain in the residue. Recently, the analyses of samples taken at different ground's depths confirmed their presence. This paper presents the methodology used to calculate the derived concentration level to ensure that the reference dose level of 0.1 mSv y-1 used as radiological criteria. In this study, a radiological impact assessment was performed modeling the area as recreational scenario. The modelization study was carried out with the code RESRAD considering as exposure pathways, external irradiation, inadvertent ingestion of soil, inhalation of resuspended particles, and inhalation of radon (Rn-222). As result was concluded that, if the concentration of Ra-226 in the first 15 cm of soil is lower than, 0.34 Bq g{sup -1}, the dose would not exceed the reference dose. Applying this value as a derived concentration level and comparing with the results of measurements on the ground, some areas with a concentration of activity slightly higher than latter were found. In these zones the remediation proposal has been to cover with a layer of 15 cm of clean material. This action represents a reduction of 85% of the dose and ensures compliance with the reference dose. (authors)

  14. Uranium, thorium and rare earth elements in macrofungi: what are the genuine concentrations?

    PubMed

    Borovička, Jan; Kubrová, Jaroslava; Rohovec, Jan; Randa, Zdeněk; Dunn, Colin E

    2011-10-01

    Concentrations of uranium, thorium and rare earth elements (REE) in 36 species of ectomycorrhizal (26 samples) and saprobic (25 samples) macrofungi from unpolluted sites with differing bedrock geochemistry were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Analytical results are supported by use of certified reference materials (BCR-670, BCR-667, NIST-1575a) and the reliability of the determination of uranium was verified by epithermal neutron activation analysis (ENAA). It appears that data recently published on these elements are erroneous, in part because of use of an inappropriate analytical method; and in part because of apparent contamination by soil particles resulting in elevated levels of thorium and REE. Macrofungi from unpolluted areas, in general, did not accumulate high levels of the investigated metals. Concentrations of uranium and thorium were generally below 30 and 125 μg kg(-1) (dry weight), respectively. Concentrations of REE in macrofungi did not exceed 360 μg kg(-1) (dry weight) and their distribution more or less followed the trend observed in post-Archean shales and loess.

  15. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter

  16. Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range.

    PubMed

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-07-01

    A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0-1,200 and 0-2,000 μg L(-1) Th and U, respectively). Limits of detection reached are 5.9 ηg L(-1) of uranium and 60 ηg L(-1) of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method. PMID:21573729

  17. Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range.

    PubMed

    Avivar, Jessica; Ferrer, Laura; Casas, Montserrat; Cerdà, Víctor

    2011-07-01

    A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV-MSFIA makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and uranium(VI) in a wide concentration range (0-1,200 and 0-2,000 μg L(-1) Th and U, respectively). Limits of detection reached are 5.9 ηg L(-1) of uranium and 60 ηg L(-1) of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method.

  18. Estimation of surface anthropogenic radioactivity concentrations from NaI(Tl) pulse-height distribution observed at monitoring station.

    PubMed

    Hirouchi, J; Yamazawa, H; Hirao, S; Moriizumi, J

    2015-04-01

    A method of estimating surface radioactivity concentrations of key anthropogenic radionuclides from NaI(Tl) pulse-height distribution observed at a monitoring station (MS) was discussed. In the estimation, a realistic assumption on geometric distribution of source and obstacles around the detector of the MS including the infiltration of radionuclides into the ground was used and the results were compared with ones with a commonly used assumption of a uniformly distributed plane source. The surface radioactivity concentration was determined by comparing the count rates at the full-energy peak ranges between observation and calculation with an electron-photon transport code EGS5. It was shown that the estimated absolute values of concentration differed by a factor of ∼1.5 depending on the assumption of infiltration depth. The estimated surface concentrations of (131)I, (134)Cs and (137)Cs were in good agreement with ones determined by the in situ measurements with an HPGe detector and the cumulative values of daily surface depositions. PMID:25313172

  19. Sensitivity of pollutant concentrations towards anthropogenic emissions: A case study over Indian region using WRF/Chem model

    NASA Astrophysics Data System (ADS)

    Ansari, Tabish; Gunthe, Sachin S.

    2015-04-01

    Concentration of an air pollutant over a given region is generally associated with the emissions, regional meteorology, and topographic conditions in addition to the chemical transformation of the pollutant. In general, the role of meteorology is often relegated in policymaking and the entire narrative of air pollution mostly revolves around the emissions. However, there may be regions where the local meteorology, in some seasons or even perennially, may predominantly govern the overall concentration, and the emissions have a little role to play. For instance, the concentrations may be high in a region despite significantly reducing the emissions. Similarly, there may be other regions wherein the prevailing meteorology would cleanse the pollutant even with high emission rates. Thus, if we better understand the seasonal meteorology of smaller regions well and their role in dispersing various pollutants, it would lead to more robust policy formulations. Therefore, there is a need to study the contribution of meteorology as isolated from the emissions, over the pollutant concentrations. In the present study we have used the on-line coupled chemical transport model WRF/Chem to investigate the role of meteorology in determining pollutant concentrations over the Indian tropical region. By using the SEAC4RS emission for the months of April, July, and December, which represents three important meteorological seasons (summer, monsoon, and winter respectively) over India we have performed the simulations of ozone (O3), oxides of nitrogen (NOX), carbon monoxide (CO), and sulphur dioxide (SO2); representative scenario. Further, to assess the role of meteorology alone all the anthropogenic emissions were flattened over the entire continental India (given as one value); flat emission scenario. Our simulations show that during the month of April and December the concentration levels of the major pollutants are largely governed by the meteorology, whereas during the month of July

  20. Measuring methane concentrations from anthropogenic and natural sources using airborne imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Frankenberg, C.; Roberts, D. A.

    2013-12-01

    Two quantitative retrieval techniques were developed for measuring methane (CH4) enhancements for concentrated plumes using high spatial and moderate spectral resolution data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). An Iterative Maximum a Posteriori Differential Optical Absorption Spectroscopy (IMAP-DOAS) algorithm performed well for a homogenous ocean scene containing natural CH4 emissions from the Coal Oil Point (COP) seeps near Santa Barbara, California. A hybrid approach using Singular Value Decomposition (SVD) was particularly effective for terrestrial surfaces given it could better account for highly variable surface reflectance of complex urban environments. These techniques permitted mapping of a distinct plume at COP consistent with known seep locations and local wind direction, with maximum near surface enhancements of 2.85 ppm CH4 above background. At the Inglewood Oil Field, a CH4 plume was observed immediately downwind of two hydrocarbon storage tanks with a maximum concentration of 8.45 ppm above background. Results from a field campaign using the next generation sensor (AVIRISng) and controlled CH4 releases will also be discussed. AVIRIS-like sensors offer the potential to better constrain both CH4 and CO2 emissions on local and regional scales, including sources of increasing concern like industrial point source emissions and fugitive CH4 from the oil and gas industry. Fig. 1. CH4 plumes and measured enhancements for the COP seeps (top) and hydrocarbon storage tanks (bottom).

  1. Does anthropogenic nitrogen enrichment increase organic nitrogen concentrations in runoff from forested and human-dominated watersheds?

    USGS Publications Warehouse

    Pellerin, B.A.; Kaushal, S.S.; McDowell, W.H.

    2006-01-01

    Although the effects of anthropogenic nitrogen (N) inputs on the dynamics of inorganic N in watersheds have been studied extensively, "the influence of N enrichment on organic N loss" is not as well understood. We compiled and synthesized data on surface water N concentrations from 348 forested and human-dominated watersheds with a range of N loads (from less than 100 to 7,100 kg N km-2 y-1) to evaluate the effects of N loading via atmospheric deposition, fertilization, and wastewater on dissolved organic N (DON) concentrations. Our results indicate that, on average, DON accounts for half of the total dissolved N (TDN) concentrations from forested watersheds, but it accounts for a smaller fraction of TDN in runoff from urban and agricultural watersheds with higher N loading. A significant but weak correlation (r 2 = 0.06) suggests that N loading has little influence on DON concentrations in forested watersheds. This result contrasts with observations from some plot-scale N fertilization studies and suggests that variability in watershed characteristics and climate among forested watersheds may be a more important control on DON losses than N loading from atmospheric sources. Mean DON concentrations were positively correlated, however, with N load across the entire land-use gradient (r 2 = 0.37, P < 0.01), with the highest concentrations found in agricultural and urban watersheds. We hypothesize that both direct contributions of DON from wastewater and agricultural amendments and indirect transformations of inorganic N to organic N represent important sources of DON to surface waters in human-dominated watersheds. We conclude that DON is an important component of N loss in surface waters draining forested and human-dominated watersheds and suggest several research priorities that may be useful in elucidating the role of N enrichment in watershed DON dynamics. ?? 2006 Springer Science+Business Media, Inc.

  2. The spatial distribution pattern of heavy metal concentrations in urban soils — a study of anthropogenic effects in Berehove, Ukraine

    NASA Astrophysics Data System (ADS)

    Vince, Tímea; Szabó, György; Csoma, Zoltán; Sándor, Gábor; Szabó, Szilárd

    2014-09-01

    In the present study we examined the Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn contamination levels of the soils of Berehove, a small city in West-Ukraine. As a first step we determined the spatial distribution of the heavy metal contents of the urban soils; then, by studying the land use structure of the city and by statistical analysis we identified the major sources of contamination; we established a matrix of correlations between the heavy metal contents of the soils and the different types of land use; and finally, we drew a conclusion regarding the possible origin(s) of these heavy metals. By means of multivariate statistical analysis we established that of the investigated metals, Ba, Cd, Cu, Pb and Zn accumulated in the city's soils primarily as a result of anthropogenic activity. In the most polluted urban areas (i.e. in the industrial zones and along the roads and highways with heavy traffic), in the case of several metals (Ba, Cd, Cu, Pb, Zn) we measured concentration levels even two or three times higher than the threshold limit values. Furthermore, Cr, Fe and Ni are primarily of lithogenic origin; therefore, the soil concentrations of these heavy metals depend mainly on the chemical composition of the soil-forming rocks.

  3. Effect of SO2 concentration on SOA formation in a photorreactor from a mixture of anthropogenic hydrocarbons and HONO

    NASA Astrophysics Data System (ADS)

    García Vivanco, Marta; Santiago, Manuel; García Diego, Cristina; Borrás, Esther; Ródenas, Milagros; Martínez-Tarifa, Adela

    2010-05-01

    Sulfur dioxide (SO2) is an important urban atmospheric pollutant, mainly produced by the combustion of fossil fuels containing sulfur. In the atmosphere, SO2 can react with OH radicals to form sulfuric acid, which can condense to form acidic aerosol. Sulfuric acid particles act as an acid catalyst for some heterogeneous carbonyl reactions like hydration, polymerization or acetals formation, which may lead to a large increase on SOA mass. In order to evaluate the effect of the SO2 concentration on SOA formation, 3 experiments were performed during the campaign carried out by CIEMAT on the EUPHORE facility (CEAM, Valencia, Spain) during June- July 2008. The objective of the campaign was to evaluate the effect of different experimental conditions on SOA formation from the photooxidation of some anthropogenic and biogenic VOCs using HONO as oxidant. Experiment on 6/17/08 was selected as base case (no SO2 was introduced) and experiments 6/26/08 and 7/1/08 were selected as high SO2 (2600 ug/m3) and low SO2 (60 ug/m3) concentration experiments respectively. In the three experiments a mixture of toluene, 1,3,5-TMB (trimethylbenzene), o-xylene and octane was selected as the parent VOCs. Single and coupled to mass spectroscopy gas cromatography (GC and GC/MS), as well as high performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR) were used to measure the initial VOCs and oxidant concentrations decay and the formation of gas phase oxidation products through the experiments. Aerosol size distribution and concentration were measured with SMPS (scanning mobility particle sizer) and TEOM (tapered element oscillating monitor) respectively. In addition, analysis of the organic and inorganic aerosol content was also performed via filter sampling followed by GC/MS and ionic chromatography (for organic and inrganic content respectively). Comparing the filters collected in the three experiments, clearly the largest mass aerosol formation is observed

  4. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes.

    PubMed

    Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I; Soler, Albert; Baquero, Juan Carlos

    2016-01-15

    High ammonium (NH4), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH4, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH4, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ(15)NNH4 values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water of sufficient quality for

  5. Origin of high ammonium, arsenic and boron concentrations in the proximity of a mine: Natural vs. anthropogenic processes.

    PubMed

    Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I; Soler, Albert; Baquero, Juan Carlos

    2016-01-15

    High ammonium (NH4), arsenic (As) and boron (B) concentrations are found in aquifers worldwide and are often related to human activities. However, natural processes can also lead to groundwater quality problems. High NH4, As and B concentrations have been identified in the confined, deep portion of the Niebla-Posadas aquifer, which is near the Cobre Las Cruces (CLC) mining complex. The mine has implemented a Drainage and Reinjection System comprising two rings of wells around the open pit mine, were the internal ring drains and the external ring is used for water reinjection into the aquifer. Differentiating geogenic and anthropogenic sources and processes is therefore crucial to ensuring good management of groundwater in this sensitive area where groundwater is extensively used for agriculture, industry, mining and human supply. No NH4, As and B are found in the recharge area, but their concentrations increase with depth, salinity and residence time of water in the aquifer. The increased salinity down-flow is interpreted as the result of natural mixing between infiltrated meteoric water and the remains of connate waters (up to 8%) trapped within the pores. Ammonium and boron are interpreted as the result of marine solid organic matter degradation by the sulfate dissolved in the recharge water. The light δ(15)NNH4 values confirm that its origin is linked to marine organic matter. High arsenic concentrations in groundwater are interpreted as being derived from reductive dissolution of As-bearing goethite by dissolved organic matter. The lack of correlation between dissolved Fe and As is explained by the massive precipitation of siderite, which is abundantly found in the mineralization. Therefore, the presence of high arsenic, ammonium and boron concentrations is attributed to natural processes. Ammonium, arsenic, boron and salinity define three zones of groundwater quality: the first zone is close to the recharge area and contains water of sufficient quality for

  6. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    SciTech Connect

    Méndez-García, C.; Montero-Cabrera, M. E.; Renteria-Villalobos, M.; García-Tenorio, R.

    2008-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. ²³²Th-series, ²³⁸U-series, ⁴⁰K and ¹³⁷Cs activity concentrations (AC, Bq kg⁻¹) were determined by gamma spectrometry with a high purity Ge detector. ²³⁸U and ²³⁴U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to ²¹⁰Pb activities. Results were verified by ¹³⁷Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High ²³⁸U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) ²³⁴U/²³⁸U and ²³⁸U/²²⁶Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. ²³²Th/²³⁸U, ²²⁸Ra/²²⁶Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  7. Hexavalent uranium diffusion into soils from concentrated acidic and alkaline solutions

    SciTech Connect

    Tokunaga, Tetsu K.; Wan, Jiamin; Pena, Jasquelin; Sutton, Stephen R.; Newville, Matthew

    2004-03-29

    Uranium contamination of soils and sediments often originates from acidic or alkaline waste sources, with diffusion being a major transport mechanism. Measurements of U(VI) diffusion from initially pH 2 and pH 11 solutions into a slightly alkaline Altamont soil and a neutral Oak Ridge soil were obtained through monitoring uptake from boundary reservoirs and from U concentration profiles within soil columns. The soils provided pH buffering, resulting in diffusion at nearly constant pH. Micro x-ray absorption near edge structure spectra confirmed that U remained in U(VI) forms in all soils. Time trends of U(VI) depletion from reservoirs, and U(VI) concentration profiles within soil columns yielded K{sub d} values consistent with those determined in batch tests at similar concentrations ({approx} 1 mM), and much lower than values for sorption at much lower concentrations (nM to {mu}M). These results show that U(VI) transport at high concentrations can be relatively fast at non-neutral pH, with negligible surface diffusion, because of weak sorption.

  8. Effects of chronic exposure to environmentally relevant concentrations of waterborne depleted uranium on the digestive tract of zebrafish, Danio rerio.

    PubMed

    Augustine, Starrlight; Pereira, Sandrine; Floriani, Magali; Camilleri, Virginie; Kooijman, Sebastiaan A L M; Gagnaire, Béatrice; Adam-Guillermin, Christelle

    2015-04-01

    Uranium is a naturally occurring element, but activities linked to the nuclear fuel cycle can increase background levels in the surrounding waters. For this reason it is important to understand how this affects organisms residing in the water column. The objective of this study was to assess histopathological effects of uranium on the gut wall of a widely used model organism: zebrafish, Danio rerio. To this end we exposed zebrafish to 84 and 420 nM depleted uranium for over a month and then examined the histology of intestines of exposed individuals compared to controls. The gut wall of individuals exposed to 84 and 420 nM of uranium had large regions of degraded mucosa. Using transmission electron microscopy (TEM) coupled to energy-dispersive X-ray spectroscopy microanalysis (EDX) we found that uranium induced a decrease in the amount of calcium containing mitochondrial matrix granules per mitochondria. This is suggestive of perturbations to cellular metabolism and more specifically to cellular calcium homeostasis. TEM-EDX of the gut wall tissue further showed that some uranium was internalized in the nucleus of epithelial cells in the 420 nM treatment. Fluorescent in situ hybridization using specific probes to detect all eubacteria was performed on frozen sections of 6 individual fish in the 84 nM and 420 nM treatments. Bacterial colonization of the gut of individuals in the 420 nM seemed to differ from that of the controls and 84 nM individuals. We suggest that host-microbiota interactions are potentially disturbed in response to uranium induced stress. The damage induced by waterborne uranium to the gut wall did not seem to depend on the concentration of uranium in the media. We measure whole body residues of uranium at the end of the experiment and compute the mean dose rate absorbed for each condition. We discuss why effects might be uncoupled from external concentration and highlight that it is not so much the external concentration but the dynamics of

  9. Effects of chronic exposure to environmentally relevant concentrations of waterborne depleted uranium on the digestive tract of zebrafish, Danio rerio.

    PubMed

    Augustine, Starrlight; Pereira, Sandrine; Floriani, Magali; Camilleri, Virginie; Kooijman, Sebastiaan A L M; Gagnaire, Béatrice; Adam-Guillermin, Christelle

    2015-04-01

    Uranium is a naturally occurring element, but activities linked to the nuclear fuel cycle can increase background levels in the surrounding waters. For this reason it is important to understand how this affects organisms residing in the water column. The objective of this study was to assess histopathological effects of uranium on the gut wall of a widely used model organism: zebrafish, Danio rerio. To this end we exposed zebrafish to 84 and 420 nM depleted uranium for over a month and then examined the histology of intestines of exposed individuals compared to controls. The gut wall of individuals exposed to 84 and 420 nM of uranium had large regions of degraded mucosa. Using transmission electron microscopy (TEM) coupled to energy-dispersive X-ray spectroscopy microanalysis (EDX) we found that uranium induced a decrease in the amount of calcium containing mitochondrial matrix granules per mitochondria. This is suggestive of perturbations to cellular metabolism and more specifically to cellular calcium homeostasis. TEM-EDX of the gut wall tissue further showed that some uranium was internalized in the nucleus of epithelial cells in the 420 nM treatment. Fluorescent in situ hybridization using specific probes to detect all eubacteria was performed on frozen sections of 6 individual fish in the 84 nM and 420 nM treatments. Bacterial colonization of the gut of individuals in the 420 nM seemed to differ from that of the controls and 84 nM individuals. We suggest that host-microbiota interactions are potentially disturbed in response to uranium induced stress. The damage induced by waterborne uranium to the gut wall did not seem to depend on the concentration of uranium in the media. We measure whole body residues of uranium at the end of the experiment and compute the mean dose rate absorbed for each condition. We discuss why effects might be uncoupled from external concentration and highlight that it is not so much the external concentration but the dynamics of

  10. Groundwater radon, radium and uranium concentrations in Região dos Lagos, Rio de Janeiro State, Brazil.

    PubMed

    Almeida, R M R; Lauria, D C; Ferreira, A C; Sracek, O

    2004-01-01

    Ground water from Região dos Lagos, a coastal area of Rio de Janeiro state, was analysed for (226)Ra, (228)Ra, (222)Rn, (238)U, major ion concentrations, and physico-chemical parameters were also measured. Concentrations values ranged from <0.002 to 0.492 Bq l(-1) for (226)Ra, from <0.01 to 1.50 Bq l(-1) for (228)Ra and from < 1.0 x 10(-4) to 8.0 x 10(-2) Bq l(-1) for (238)U. Detectable (222)Rn concentrations (>3 Bq l(-1)) were found only in two samples. The spatial distribution of Ra concentration delineated one distinct area and some hot spots with high Ra concentration. Low pH value is the most important water parameter linked to high radium concentration. This is probably related to limited adsorption of radium on soil ferric oxides and hydroxides at low pH range. There was a significant correlation between uranium concentrations and electrical conductivity values, and also between uranium concentrations and concentrations of Ca, Mg, Na, K, and Cl, indicating sea water impact. Uranium concentrations were lower than maximum contaminant level for drinking water, whereas 17 out of the 88 ground water samples had levels of radium that exceeded the maximum contaminant level for tap water. The total annual effective dose for adult due to the water consumption reaches values up to 0.8 mSv.

  11. Uranium hydrogeochemical survey of well waters from an area around Pie Town, Catron County, West-Central New Mexico, including concentrations of twenty-three additional elements

    SciTech Connect

    Morgan, T.L.; George, W.E.; Hensley, W.K.; Thomas, G.J.; Langhorst, A.L.

    1980-10-01

    As part of the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the National Uranium Resource Evaluation (NURE) sponsored by the US Department of Energy (DOE), the Los Alamos Scientific Laboratory (LASL) conducted a detailed hydrogeochemical survey of well waters in a 4250-km/sup 2/ area near Pie Town in west-central New Mexico. A total of 300 well samples was collected and analyzed for uranium and 23 other elements. The results of these analyses and carbonate and bicarbonate ion concentrations are presented in the Appendixes of this report. Uranium concentrations range from below the detection limit of 0.02 parts per billion (ppB) to 293.18 ppB and average 8.71 ppB. Samples containing high levels of uranium were collected from the Largo Creek valley west of Quemado, from a small area about 6 km east of Quemado, from a small area surrounding Pie Town, and from scattered locations in the area surrounding Adams Diggings north of Pie Town. Most of the samples containing high uranium concentrations were collected from wells associated with the volcanic sedimentary facies of the Datil formation. This formation is a likely source of mobile uranium that may be precipitating in the underlying Baca formation, a known uranium host unit. Bicarbonate ion concentration, while proportional to uranium concentration in some cases, is not a strong controlling factor in the uranium concentrations in samples from this area.

  12. Preliminary results on variations of radon concentration associated with rock deformation in a uranium mine

    NASA Astrophysics Data System (ADS)

    Verdoya, Massimo; Bochiolo, Massimo; Chiozzi, Paolo; Pasquale, Vincenzo; Armadillo, Egidio; Rizzello, Daniele; Chiaberto, Enrico

    2013-04-01

    Time-series of radon concentration and environmental parameters were recently recorded in a uranium mine gallery, located in the Maritime Alps (NW Italy). The mine was bored in metarhyolites and porphyric schists mainly composed by quartz, feldspar, sericite and fluorite. U-bearing minerals are generally concentrated in veins heterogeneously spaced and made of crystals of metaautunite and metatorbernite. Radon air concentration monitoring was performed with an ionization chamber which was placed at the bottom of the gallery. Hourly mean values of temperature, pressure, and relative humidity were also measured. External data of atmospheric temperature, pressure and rainfall were also available from a meteorological station located nearby, at a similar altitude of the mine. The analysis of the time series recorded showed variation of radon concentration, of large amplitude, exhibiting daily and half-daily periods, which do not seem correlated with meteorological records. Searching for the origin of radon concentration changes and monitoring their amplitude as a function of time can provide important clues on the complex emanation process. During this process, radon reaches the air- and water-filled interstices by recoil and diffusion, where its migration is directed towards lower concentration regions, following the local gradient. The radon emanation from the rock matrix could also be controlled by stress changes acting on the rate of migration of radon into fissures, and fractures. This may yield emanation boosts due to rock extension and the consequent crack broadening, and emanation decrease when joints between cracks close. Thus, besides interaction and mass transfer with the external atmospheric environment, one possible explanation for the periodic changes in radon concentrations in the investigated mine, could be the variation of rock deformation related to lunar-solar tides. The large variation of concentration could be also due to the fact that the mine is

  13. Analysis of the risk of transporting uranium ore concentrates by truck

    SciTech Connect

    Geffen, C.A.

    1981-07-01

    This report evaluates the risks involved with shipping uranium ore concentrates by truck in an attempt to provide some perspective on the system safety issues. The basic probabilistic risk evaluation methodology used in this study is similar to that employed by Pacific Northwest Laboratory (PNL) in a series of risk analyses on the transportation of potentially hazardous energy materials. The risk model has been constructed as a series of separate analysis steps to allow the system risk to be readily reevaluated as additional data become available or as postulated system characteristics change. The reslts of this analysis show that the risks to the public health and safety from yellowcake releases during a transportation accident are insignificant. Accidents involving truck shipments of yellowcake are expected to occur at a rate of about ten a year. However, only one-fifth of these accidents, or about two a year, are expected to cause a release of yellowcake to the environment. None of these accidents was estimated to produce any potential fatalities. The low concentration of radioactivity distributed throughout the material resulted in no significant increase in radiation doses above normal background levels to members of the general public.

  14. Anthropogenic and authigenic uranium in marine sediments of the central Gulf of California adjacent to the Santa Rosalía mining region.

    PubMed

    Shumilin, Evgueni; Rodríguez-Figueroa, Griselda; Sapozhnikov, Dmitry; Sapozhnikov, Yuri; Choumiline, Konstantin

    2012-10-01

    To investigate the causes of uranium (U) enrichment in marine sediments in the eastern sector of the Gulf of California, surface sediments and sediment cores were collected adjacent to the Santa Rosalía copper mining region in the Baja California peninsula. Three coastal sediment cores were found to display high concentrations of U (from 54.2 ± 7.3 mg kg(-1) to 110 ± 13 mg kg(-1)) exceeding those found in the deeper cores (1.36 ± 0.26 mg kg(-1) in the Guaymas Basin to 9.31 ± 3.03 mg kg(-1) in the SR63 core from the suboxic zone). The contribution of non-lithogenic U (estimated using scandium to normalize) to the total U content in sediments of three coastal cores varied from 97.2 ± 0.4 % to 98.82 % versus 49.8 ± 3 % (Guaymas Basin) to 84.2 ± 8.2 % (SR62 core) in the deeper cores. The U content record in a lead-210 ((210)Pb)-dated core had two peaks (in 1923 and 1967) corresponding to the history of ancient mining and smelting activities in Santa Rosalía.

  15. Simultaneous determination of nitric acid and uranium concentrations in aqueous solution from measurements of electrical conductivity, density, and temperature

    SciTech Connect

    Spencer, B.B.

    1991-01-01

    Nuclear fuel reprocessing plants handle aqueous solutions of nitric acid and uranium in large quantities. Automatic control of process operations requires reliable measurements of these solutes concentration, but this is difficult to directly measure. Physical properties such as solution density and electrical conductivity vary with solute concentration and temperature. Conductivity, density and temperature can be measured accurately with relatively simple and inexpensive devices. These properties can be used to determine solute concentrations will good correlations. This paper provides the appropriate correlations for solutions containing 2 to 6 Molar (M) nitric acid and 0 to 300 g/L uranium metal at temperatures from 25--90{degrees}C. The equations are most accurate below 5 M nitric acid, due to a broad maximum in the conductivity curve at 6 M. 12 refs., 9 figs., 6 tabs.

  16. Concentration of Uranium Radioisotopes in Albanian Drinking Waters Measured by Alpha Spectrometry

    NASA Astrophysics Data System (ADS)

    Bylyku, Elida; Cfarku, Florinda; Deda, Antoneta; Bode, Kozeta; Fishka, Kujtim

    2010-01-01

    Uranium is a radioactive material that is frequently found in rocks and soil. When uranium decays, it changes into different elements that are also radioactive, including radon, a gas that is known to cause a lung cancer. The main concern with uranium in drinking water is harm to the kidneys. Public water systems are required to keep uranium levels at or below 500 mBq per liter to protect against kidney damage. Such an interest is needed due to safety, regulatory compliance and disposal issue for uranium in the environment since uranium is included as an obligatory controlled radionuclide in the European Legislation (Directive 98/83 CE of Council of 03.11.1998). The aim of this work is to measure the levels of uranium in drinking and drilled well waters in Albania. At first each sample was measured for total Alpha and total Beta activity. The samples with the highest levels of total alpha activity were chosen for the determination of uranium radioisotopes by alpha spectrometry. A radiochemical procedure using extraction with TBP (Tri-Butyl-Phosphate) is used in the presence of U232 as a yield tracer. Thin sources for alpha spectrometry are prepared by electrodepositing on to stainless steel discs. The results of the U238 activity measured in the different samples, depending from their geological origin range between 0.55-13.87 mBq/l. All samples measured results under the European Directive limits for U238 (5-500 mBq/1), Dose Coefficients according to Directive 96/29 EURATOM.

  17. Laser-luminescent determination of uranium in natural waters with concentration of titanium hydroxide and using sodium polysilicate

    SciTech Connect

    Nikitina, S.A.; Stepanov, A.V.

    1987-05-01

    Two methods for determining uranium in samples with a high content of quenching agents are compared, taking as an example the analysis of waters from the Vuoksa River, Baltic Sea and Finnish Bay. The first of these methods was developed by the authors and consists in concentrating uranium on TiO/sub 2/ x nH/sub 2/O under dynamic conditions, followed by laser luminescent determination at 77/sup 0/K in 0.1 M H/sub 2/SO/sub 4/. The second method consists in direct recording of the luminescence of uranium in a 0.7% solution of sodium polysilicate at room temperature. The detection limit of the second method is estimated by the authors as 2 x 10/sup -11/ g/ml, while the detection limit of the first method is lower because concentration is used. The method is especially suitable for analysis of natural waters with a high concentration of hydrolyzable elements. Quenching rate constants of uranyl were measured for a large number of ions in a polysilicate medium.

  18. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

    DOE PAGESBeta

    Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; et al

    2014-04-13

    In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive rangemore » of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.« less

  19. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia.

    PubMed

    Keegan, Elizabeth; Kristo, Michael J; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; Plaue, Jonathan; Wong, Henri; Davis, Joel; Loi, Elaine; Reinhard, Mark; Hutcheon, Ian

    2014-07-01

    Early in 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. During the search of the laboratory, a small glass jar labelled "Gamma Source" and containing a green powder was discovered. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterise and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key 'nuclear forensic signatures' used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.

  20. Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

    SciTech Connect

    Keegan, Elizabeth; Kristo, Michael J.; Colella, Michael; Robel, Martin; Williams, Ross; Lindvall, Rachel; Eppich, Gary; Roberts, Sarah; Borg, Lars; Gaffney, Amy; Plaue, Jonathan; Wong, Henri; Davis, Joel; Loi, Elaine; Reinhard, Mark; Hutcheon, Ian

    2014-04-13

    In early 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. While searching the laboratory, they discovered a small glass jar labelled “Gamma Source” and containing a green powder. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterize and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.

  1. Uranium, Thorium and Potassium concentrations in agricultural and grazing land soils of Europe

    NASA Astrophysics Data System (ADS)

    De Vivo, Benedetto; Cicchella, Domenico; Albanese, Stefano; Birke, Manfred; Demetriades, Alecos; De Vos, Walter; Dinelli, Enrico; Lima, Annamaria; O'Connor, Patrick J.; Salpeteur, Ignace; Tarvainen, Timo

    2014-05-01

    Two thousand two hundred and eighteen samples of agricultural soil and 2127 samples of grazing land soil were collected with an average sampling density of 1 site per 2500 km2 over an area of 5.6 million km2 across Europe. The uranium concentrations over the survey area vary from <0.1 to 23.55 mg/kg in agricultural soil and from <0.1 to 73.32 mg/kg in grazing land soil, with a median value of 0.77 and 0.74, respectively. The median Th content is 2.89 mg/kg in agricultural soil and 2.5 mg/kg in grazing land soil; the range varies from <0.1 to 63.1 mg/kg in agricultural soil and <0.1 to 55.64 mg/kg in grazing land soil. The median potassium content is 16 000 mg/kg in agricultural soil and 14 900 mg/kg in grazing land soil, with a range between 241 mg/kg and 79,200 mg/kg in agricultural soil and between 241 mg/kg and 50000 mg/kg in grazing land soil. The new data define the soil geochemical U, Th and K background for European agricultural and grazing land soil, providing information of crucial importance to increase our knowledge about 'soil quality' at the European scale. Such data are essential for agriculture, animal and human health, setting of environmental standards, water quality, land use planning and the identification of mineral resource potential.

  2. Establishing the Origin of Elevated Uranium Concentrations in Groundwater near the Central Ogcheon Metamorphic Belt, Korea.

    PubMed

    Moon, S H; Hwang, J; Lee, J Y; Hyun, S P; Bae, B K; Park, Y

    2013-01-01

    We examined the origin of the U-enriched groundwater in Daejeon, near the Ogcheon U zone in Korea. For this study, groundwater ionic species and C, S, and Sr isotopic compositions were analyzed. The U-enriched groundwater occurred only in the Daejeon granite region, while all the groundwater in the Ogcheon Supergroup showed very low U concentrations. In the granite region, the pedospheric or atmospheric origin of dissolved C and S means that the aquifer has been well connected to the oxidized surface environment. The Sr/Sr ratios indicated a lithospheric origin of Sr. Groundwater isotopic compositions in the Ogcheon belt varied greatly, indicating their complex sources. In this region, dissolved C originated from graphite-rich slate and limestone. The broad range of δS suggested that the composite sources included atmospheric SO for most groundwater, lithogenic SO for mine drainage and quarry water, and anthropogenic SO for polluted groundwater. This study indicates that the U-enriched groundwater is not related to the present U ores in the Ogcheon belt but is genetically associated with the granite body itself. The varying but considerable U contents within the granite body can be present as isolated groups. We infer that locally high U contents in the Daejeon granite might inherently be due to assimilation of the Ogcheon U-mineralized zone into granitic melt during the Mesozoic; however, the pH and Eh conditions except aquifer geology were very important factors in developing highly enriched U groundwater in the Daejeon granite region. Thermodynamic modeling highlights the importance of dissolved Ca and (bi-)carbonate in U geochemistry. PMID:23673746

  3. Establishing the Origin of Elevated Uranium Concentrations in Groundwater near the Central Ogcheon Metamorphic Belt, Korea.

    PubMed

    Moon, S H; Hwang, J; Lee, J Y; Hyun, S P; Bae, B K; Park, Y

    2013-01-01

    We examined the origin of the U-enriched groundwater in Daejeon, near the Ogcheon U zone in Korea. For this study, groundwater ionic species and C, S, and Sr isotopic compositions were analyzed. The U-enriched groundwater occurred only in the Daejeon granite region, while all the groundwater in the Ogcheon Supergroup showed very low U concentrations. In the granite region, the pedospheric or atmospheric origin of dissolved C and S means that the aquifer has been well connected to the oxidized surface environment. The Sr/Sr ratios indicated a lithospheric origin of Sr. Groundwater isotopic compositions in the Ogcheon belt varied greatly, indicating their complex sources. In this region, dissolved C originated from graphite-rich slate and limestone. The broad range of δS suggested that the composite sources included atmospheric SO for most groundwater, lithogenic SO for mine drainage and quarry water, and anthropogenic SO for polluted groundwater. This study indicates that the U-enriched groundwater is not related to the present U ores in the Ogcheon belt but is genetically associated with the granite body itself. The varying but considerable U contents within the granite body can be present as isolated groups. We infer that locally high U contents in the Daejeon granite might inherently be due to assimilation of the Ogcheon U-mineralized zone into granitic melt during the Mesozoic; however, the pH and Eh conditions except aquifer geology were very important factors in developing highly enriched U groundwater in the Daejeon granite region. Thermodynamic modeling highlights the importance of dissolved Ca and (bi-)carbonate in U geochemistry.

  4. Ra-226 concentrations in otter, Lutra canadensis, trapped near uranium tailings at Elliot Lake, Ontario

    SciTech Connect

    Wren, C.D.; Cloutier, N.R.; Lim, T.P.; Dave, N.K.

    1987-02-01

    The Elliot Lake area of Ontario, is currently the major uranium producing region of Canada. It is estimated there are 120 million tons of uranium tailings spread over 600 ha in the vicinity of Elliot Lake. The transfer and fate of uranium-series radionuclides from tailing sites remain primary ecological concerns in these areas. It has been demonstrated that the levels of radionuclides, including Ra-226, are elevated in vegetation, small mammals and fish living on or near tailing disposal sites. However, the transfer potential of Ra-226 to predatory species has not been examined in detail. The objective of this study was to measure Ra-226 levels in otters (Lutra canadensis), captured near tailing sites, to provide further information on the fate of radionuclides in the environment.

  5. Determining the isotopic concentration of uranium from vector representation of the gamma spectrum

    NASA Astrophysics Data System (ADS)

    White, Tristan Glover

    Gamma emissions from Uranium-235 in a source of interest were compared to gamma emissions from Protactinium-234m (which is in equilibrium with Uranium-238) in order to determine the isotopic composition of the source. The 144 keV gamma ray from U-235 was compared with 1001 keV gamma ray from Pa-234m. Two analytical methods were compared: the relative activity method and the vector representation method. The relative activity method is similar to the (standard) relative intensity method, but accounts for more variables. Calculations were performed using both methods in order to evaluate precision and accuracy. Relative activity compares the number of counts under one gamma-ray peak from a reference source to the number of counts under another peak from an unknown source. This method is sensitive to systematic errors in the efficiency calibration of the detector when two different peaks with different energies are used. Vector representation compares the count ratio of two gamma-ray peaks from one source to the count ratio of the same two gamma-ray peaks from another source. Vector representation was found to be practical for analyzing depleted uranium, but not highly enriched uranium (HEU), due to different branching ratios and detector efficiency.

  6. Decrease of Zn, Cd and Pb concentrations in marine fish species over a decade as response to reduction of anthropogenic inputs: the example of Tagus estuary.

    PubMed

    Raimundo, Joana; Pereira, Patrícia; Caetano, Miguel; Cabrita, Maria Teresa; Vale, Carlos

    2011-12-01

    Concentrations of Zn, Cd and Pb were measured in muscle of pelagic, demersal and benthic fishes, captured in the coastal area adjoining the Tagus estuary (Portugal), in 1998 and 2010. Additionally, Pb and Cd were determined in estuarine waters, showing a pronounced decrease between 1999 and 2010. Accordingly, specimens captured in 2010 presented significantly lower metal concentrations than individuals caught in 1998. Reductions were more evident for Pb (reduction of 59-99%) than for Cd (14-93%) and Zn (17-54%). Values in pelagic and demersal species exhibited higher reductions than in benthic species. Decrease of metal concentrations in fish appears thus to reflect the improvement of estuarine water quality as anthropogenic sources have been reduced or eliminated. Furthermore, it emphasises the usefulness of the descriptor "Contaminants in Fish" to assess the efficiency of measures to achieve a good environmental status, in the scope of the Marine Strategy Framework Directive.

  7. Influence of season growth, soils and irrigation water composition on the concentration of uranium in two lettuce (Lactuca sativa L.) varieties. Field experiments

    NASA Astrophysics Data System (ADS)

    Abreu, M. M.; Neves, O.; Marcelino, M.

    2012-04-01

    Former uranium mines areas are frequently the sources of environmental radionuclides problems even many years after the closure of mining operations. A concern for inhabitants from mining areas is the use of contaminated land or irrigation water for agriculture, and the potential transfer of metals from soils to vegetables, and to humans through the food chain. The main aim of this study was to compare the uranium concentration in lettuce (Lactuca sativa L. varieties Marady and Romana) grown in different seasons (autumn and summer) and exposed to high and low uranium concentrations both in irrigation water and agricultural soil. The content of uranium in irrigation water, soil (total and available fraction) and in lettuce leaf samples was analyzed in a certified laboratory. In the field experiments, two agricultural soils were divided into two plots (four replicates each); one of them was irrigated with uranium contaminated water (0.94 to 1.14 mg/L) and the other with uncontaminated water (< 0.02 mg/L). Irrigation with contaminated water together with highest soil uranium available concentration (10 to 13 mg/kg) had negative effects on both studied lettuce varieties, namely yield reduction (up to 53% and 87% in autumn and summer experiments, respectively) and increase of uranium leaf concentration (up to 1.4 and 7 fold in autumn and summer, respectively). Effect on lettuce yield was mainly due to the high soil salinity (1.01 to 6.31 mS/cm) as a consequence of high irrigation water electrical conductivity (up to 1.82 mS/cm) and low lettuce soil salinity tolerance (1 to 3 mS/cm). The highest lettuce uranium concentration (dry weight) observed was 2.13 and 5.37 mg/kg for Marady and Romana variety, respectively. The highest uranium lettuce concentration in Romana variety was also the effect of its growing in summer season when it was subject to greatest frequency and amount of water irrigation. The consumption by an adult of the lettuce that concentrate more uranium

  8. Hazard Assessment Report for Residual Uranium Concentrations in Storm Drains, Rapaport Building, Windsor, Connecticut

    SciTech Connect

    Timothy J. Vitkus; Environmental Survey and Site Assessment Program , ORISE

    2000-04-19

    A hazard assessment was conducted in the parking area of the Rapaport Building in Windsor Connecticut. The site had been a processing plant for nuclear fuels for the Navy's nuclear fuel program. The subject of the study was a storm drain that showed signs of increased radiation from enriched uranium products that had been produced or used in the adjacent building. The conclusion of the assessment is that there is no public hazard from radiation from the drain.

  9. Application of bimodal distribution to the detection of changes in uranium concentration in drinking water collected by random daytime sampling method from a large water supply zone.

    PubMed

    Garboś, Sławomir; Święcicka, Dorota

    2015-11-01

    The random daytime (RDT) sampling method was used for the first time in the assessment of average weekly exposure to uranium through drinking water in a large water supply zone. Data set of uranium concentrations determined in 106 RDT samples collected in three runs from the water supply zone in Wroclaw (Poland), cannot be simply described by normal or log-normal distributions. Therefore, a numerical method designed for the detection and calculation of bimodal distribution was applied. The extracted two distributions containing data from the summer season of 2011 and the winter season of 2012 (nI=72) and from the summer season of 2013 (nII=34) allowed to estimate means of U concentrations in drinking water: 0.947 μg/L and 1.23 μg/L, respectively. As the removal efficiency of uranium during applied treatment process is negligible, the effect of increase in uranium concentration can be explained by higher U concentration in the surface-infiltration water used for the production of drinking water. During the summer season of 2013, heavy rains were observed in Lower Silesia region, causing floods over the territory of the entire region. Fluctuations in uranium concentrations in surface-infiltration water can be attributed to releases of uranium from specific sources - migration from phosphate fertilizers and leaching from mineral deposits. Thus, exposure to uranium through drinking water may increase during extreme rainfall events. The average chronic weekly intakes of uranium through drinking water, estimated on the basis of central values of the extracted normal distributions, accounted for 3.2% and 4.1% of tolerable weekly intake.

  10. Uranium concentrations and /sup 234/U//sup 238/U activity ratios in fault-associated groundwater as possible earthquake precursors

    SciTech Connect

    Finkel, R.C.

    1981-05-01

    In order to assess the utility of uranium isotopes as fluid phase earthquake precursors, uranium concentrations and /sup 234/U//sup 238/U activity ratios have been monitored on a monthly or bimonthly basis in water from 24 wells and springs associated with Southern California fault zones. Uranium concentrations vary from 0.002 ppb at Indian Canyon Springs on the San Jacinto fault to 8.3 ppb at Lake Hughes well on the San Andreas fault in the Palmdale area. /sup 234/U//sup 238/U activity ratios vary from 0.88 at Agua Caliente Springs on the Elsinore fault to 5.4 at Niland Slab well on the San Andreas fault in the Imperial Valley. There was one large earthquake in the study area during 1979, the 15 October 1979 M = 6.6 Imperial Valley earthquake. Correlated with this event, uranium concentrations varied by a factor of more than 60 and activity ratios by a factor of 3 at the Niland Slab site, about 70 km from the epicenter. At the other sites monitored, uranium concentrations varied in time, but with no apparent pattern, while uranium activity ratios remained essentially constant throughout the monitoring period.

  11. Change of the dynamics of heavy metals concentration in atmospheric precipitation in chatkal nature reservation of the republic of uzbekistan as anthropogenic index of the atmospheric pollution

    NASA Astrophysics Data System (ADS)

    Smirnova, T.; Tolkacheva, G.

    2003-04-01

    extremely continental climate, by the abundance of days with sunshine during a year, excessive solar radiation, high mean annual temperature trend, complex orography, remoteness from the sea. The peculiar features of the mountain-and-valley circulation can cause the increase of content of different pollutants in the atmosphere (including heavy metals). In the background zone during precipitation the increase of the heavy metals concentration is possible due to the impact of anthropogenic emissions from the above-mentioned sources. The analysis of precipitation samples was made with the method of the atomic adsorption. The investigation of the dynamics of heavy metals concentrations in precipitation for the mentioned period has shown that the maximum concentration of heavy metals in precipitation is recorded during June - September, when the amount of monthly precipitation is minimum. In November when precipitation amount is minimum, the concentration of heavy metals is minimum.

  12. Uranium Industry Annual, 1992

    SciTech Connect

    Not Available

    1993-10-28

    The Uranium Industry Annual provides current statistical data on the US uranium industry for the Congress, Federal and State agencies, the uranium and electric utility industries, and the public. The feature article, ``Decommissioning of US Conventional Uranium Production Centers,`` is included. Data on uranium raw materials activities including exploration activities and expenditures, resources and reserves, mine production of uranium, production of uranium concentrate, and industry employment are presented in Chapter 1. Data on uranium marketing activities including domestic uranium purchases, commitments by utilities, procurement arrangements, uranium imports under purchase contracts and exports, deliveries to enrichment suppliers, inventories, secondary market activities, utility market requirements, and uranium for sale by domestic suppliers are presented in Chapter 2.

  13. Some factors controlling the concentration of uranium in the world ocean

    USGS Publications Warehouse

    Bloch, S.

    1980-01-01

    Low-temperature alteration of the oceanic crust is a major sink for the U supplied to the oceans and may account for about 50% of the estimated present-day input of this element. Uranium uptake by organic-rich sediments and coexisting phosphorites on continental margins is also important and may remove in excess of 10% of the total supply. High-temperature alteration of oceanic basalts, metalliferous sediments, carbonate sediments, and sediments in anoxic basins deeper than 200 m play a relatively minor role in the removal of U. Each of these sinks is responsible for the uptake of less than 5% of the overall input. ?? 1980.

  14. Impact of reduced anthropogenic emissions and century flood on the phosphorus stock, concentrations and loads in the Upper Danube.

    PubMed

    Zoboli, Ottavia; Viglione, Alberto; Rechberger, Helmut; Zessner, Matthias

    2015-06-15

    Patterns of changes in the concentration of total and soluble reactive phosphorus (TP, SRP) and suspended sediments at different flow levels from 1991 to 2013 in the Austrian Danube are statistically analyzed and related to point and diffuse emissions, as well as to extreme hydrological events. Annual loads are calculated with three methods and their development in time is examined taking into consideration total emissions and hydrological conditions. The reduction of point discharges achieved during the 1990s was well translated into decreasing TP and SRP baseflow concentrations during the same period, but it did not induce any change in the concentrations at higher flow levels nor in the annual transport of TP loads. A sharp and long-lasting decline in TP concentration, affecting all flow levels, took place after a major flood in 2002. It was still visible during another major flood in 2013, which recorded lower TP concentrations than its predecessor. Such decline could not be linked to changes in point or diffuse emissions. This suggests that, as a result of the flood, the river system experienced a significant depletion of its in-stream phosphorus stock and a reduced mobilization of TP rich sediments afterwards. This hypothesis is corroborated by the decoupling of peak phosphorus loads from peak maximum discharges after 2002. These results are highly relevant for the design of monitoring schemes and for the correct interpretation of water quality data in terms of assessing the performance of environmental management measures.

  15. Impact of reduced anthropogenic emissions and century flood on the phosphorus stock, concentrations and loads in the Upper Danube

    PubMed Central

    Zoboli, Ottavia; Viglione, Alberto; Rechberger, Helmut; Zessner, Matthias

    2015-01-01

    Patterns of changes in the concentration of total and soluble reactive phosphorus (TP, SRP) and suspended sediments at different flow levels from 1991 to 2013 in the Austrian Danube are statistically analyzed and related to point and diffuse emissions, as well as to extreme hydrological events. Annual loads are calculated with three methods and their development in time is examined taking into consideration total emissions and hydrological conditions. The reduction of point discharges achieved during the 1990s was well translated into decreasing TP and SRP baseflow concentrations during the same period, but it did not induce any change in the concentrations at higher flow levels nor in the annual transport of TP loads. A sharp and long-lasting decline in TP concentration, affecting all flow levels, took place after a major flood in 2002. It was still visible during another major flood in 2013, which recorded lower TP concentrations than its predecessor. Such decline could not be linked to changes in point or diffuse emissions. This suggests that, as a result of the flood, the river system experienced a significant depletion of its in-stream phosphorus stock and a reduced mobilization of TP rich sediments afterwards. This hypothesis is corroborated by the decoupling of peak phosphorus loads from peak maximum discharges after 2002. These results are highly relevant for the design of monitoring schemes and for the correct interpretation of water quality data in terms of assessing the performance of environmental management measures. PMID:25747371

  16. IMPACT OF URANIUM AND THORIUM ON HIGH TIO2 CONCENTRATION NUCLEAR WASTE GLASSES

    SciTech Connect

    Fox, K.; Edwards, T.

    2012-01-11

    This study focused on the potential impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. MST from the Salt Waste Processing Facility (SWPF) is also considered in the study. The KT08-series of glasses was designed to evaluate any impacts of the inclusion of uranium and thorium in glasses containing the SCIX components. All but one of the study glasses were found to be amorphous by X-ray diffraction (XRD). One of the slowly cooled glasses contained a small amount of trevorite, which is typically found in DWPF-type glasses and had no practical impact on the durability of the glass. The measured Product Consistency Test (PCT) responses for the study glasses and the viscosities of the glasses were well predicted by the current DWPF models. No unexpected issues were encountered when uranium and thorium were added to the glasses with SCIX components.

  17. Anthropogenic platinum group element (Pt, Pd, Rh) concentrations in PM10 and PM2.5 from Kolkata, India.

    PubMed

    Diong, Huey Ting; Das, Reshmi; Khezri, Bahareh; Srivastava, Bijayen; Wang, Xianfeng; Sikdar, Pradip K; Webster, Richard D

    2016-01-01

    This study investigates platinum group elements (PGEs) in the breathable (PM10) and respirable (PM2.5) fractions of air particulates from a heavily polluted Indian metro city. The samples were collected from traffic junctions at the heart of the city and industrial sites in the suburbs during winter and monsoon seasons of 2013-2014. PGE concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The PGE concentrations in the samples from traffic junctions are within the range of 2.7-111 ng/m(3) for Pd, 0.86-12.3 ng/m(3) for Pt and 0.09-3.13 ng/m(3) for Rh, and from industrial sites are within the range of 3.12-32.3 ng/m(3) for Pd, 0.73-7.39 ng/m(3) for Pt and 0.1-0.69 ng/m(3) for Rh. Pt concentrations were lower in the monsoon compared to winter while Pd concentrations increased during monsoon and Rh stayed relatively unaffected across seasons. For all seasons and locations, concentrations of Pd > Pt > Rh, indicating dominance of Pd-containing exhaust converters. Most of the PGEs were concentrated in the PM2.5 fraction. A strong correlation (R ≥ 0.62) between the PGEs from traffic junction indicates a common emission source viz. catalytic converters, whereas a moderate to weak correlation (R ≤ 0.5) from the industrial sites indicate mixing of different sources like coal, raw materials used in the factories and automobile. A wider range of Pt/Pd, Pt/Rh and Pd/Rh ratios measured in the traffic junction possibly hint towards varying proportions of PGEs used for catalyst productions in numerous rising and established car brands. PMID:27536525

  18. Anthropogenic platinum group element (Pt, Pd, Rh) concentrations in PM10 and PM2.5 from Kolkata, India.

    PubMed

    Diong, Huey Ting; Das, Reshmi; Khezri, Bahareh; Srivastava, Bijayen; Wang, Xianfeng; Sikdar, Pradip K; Webster, Richard D

    2016-01-01

    This study investigates platinum group elements (PGEs) in the breathable (PM10) and respirable (PM2.5) fractions of air particulates from a heavily polluted Indian metro city. The samples were collected from traffic junctions at the heart of the city and industrial sites in the suburbs during winter and monsoon seasons of 2013-2014. PGE concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The PGE concentrations in the samples from traffic junctions are within the range of 2.7-111 ng/m(3) for Pd, 0.86-12.3 ng/m(3) for Pt and 0.09-3.13 ng/m(3) for Rh, and from industrial sites are within the range of 3.12-32.3 ng/m(3) for Pd, 0.73-7.39 ng/m(3) for Pt and 0.1-0.69 ng/m(3) for Rh. Pt concentrations were lower in the monsoon compared to winter while Pd concentrations increased during monsoon and Rh stayed relatively unaffected across seasons. For all seasons and locations, concentrations of Pd > Pt > Rh, indicating dominance of Pd-containing exhaust converters. Most of the PGEs were concentrated in the PM2.5 fraction. A strong correlation (R ≥ 0.62) between the PGEs from traffic junction indicates a common emission source viz. catalytic converters, whereas a moderate to weak correlation (R ≤ 0.5) from the industrial sites indicate mixing of different sources like coal, raw materials used in the factories and automobile. A wider range of Pt/Pd, Pt/Rh and Pd/Rh ratios measured in the traffic junction possibly hint towards varying proportions of PGEs used for catalyst productions in numerous rising and established car brands.

  19. Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

    SciTech Connect

    Morgan, T.L.

    1980-08-01

    Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km/sup 2/ area of the quadrangle at an average density of one location per 9.86 km/sup 2/. Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations.

  20. Evaluation of the effect of implanted depleted uranium on male reproductive success, sperm concentration, and sperm velocity

    SciTech Connect

    Arfsten, Darryl P. . E-mail: darryl.arfsten@wpafb.af.mil; Schaeffer, David J.; Johnson, Eric W.; Robert Cunningham, J.; Still, Kenneth R.; Wilfong, Erin R.

    2006-02-15

    Depleted uranium (DU) projectiles have been used in battle in Iraq and the Balkans and will continue to be a significant armor-penetrating munition for the US military. As demonstrated in the Persian Gulf War, battle injury from DU projectiles and shrapnel is a possibility, and removal of embedded DU fragments from the body is not always practical because of their location in the body or their small size. Previous studies in rodents have demonstrated that implanted DU mobilizes and translocates to the gonads, and natural uranium may be toxic to spermatazoa and the male reproductive tract. In this study, the effects of implanted DU pellets on sperm concentration, motility, and male reproductive success were evaluated in adult (P1) Sprague-Dawley rats implanted with 0, 12, or 20, DU pellets of 1x2 mm or 12 or 20 tantalum (Ta) steel pellets of 1x2 mm. Twenty DU pellets of 1x2 mm (760 mg) implanted in a 500-g rat are equal to approximately 0.2 pound of DU in a 154-lb (70-kg) person. Urinary analysis found that male rats implanted with DU were excreting uranium at postimplantation days 27 and 117 with the amount dependent on dose. No deaths or evidence of toxicity occurred in P1 males over the 150-day postimplantation study period. When assessed at postimplantation day 150, the concentration, motion, and velocity of sperm isolated from DU-implanted animals were not significantly different from those of sham surgery controls. Velocity and motion of sperm isolated from rats treated with the positive control compound {alpha}-chlorohydrin were significantly reduced compared with sham surgery controls. There was no evidence of a detrimental effect of DU implantation on mating success at 30-45 days and 120-145 days postimplantation. The results of this study suggest that implantation of up to 20 DU pellets of 1x2 mm in rats for approximately 21% of their adult lifespan does not have an adverse impact on male reproductive success, sperm concentration, or sperm velocity.

  1. METHOD FOR PURIFYING URANIUM

    DOEpatents

    Knighton, J.B.; Feder, H.M.

    1960-04-26

    A process is given for purifying a uranium-base nuclear material. The nuclear material is dissolved in zinc or a zinc-magnesium alloy and the concentration of magnesium is increased until uranium precipitates.

  2. Impacts of anthropogenic emissions and cold air pools on urban to montane gradients of snowpack ion concentrations in the Wasatch Mountains, Utah

    NASA Astrophysics Data System (ADS)

    Hall, Steven J.; Maurer, Gregory; Hoch, Sebastian W.; Taylor, Raili; Bowling, David R.

    2014-12-01

    of 120, 117, 42, and 39 μeq l-1, respectively. After exposure to atmospheric particulate matter during cold pool events, surface snow concentrations peaked at 2500, 3600, 93, and 90 μeq l-1 for these ions. Median nitrogen (N) deposition in fresh urban snow samples measured 0.8 kg N ha-1 during January 2011, with similar fog/dry deposition inputs at mid-elevation montane sites. Wintertime anthropogenic air pollution represents a significant source of ions to snow-covered ecosystems proximate to urban montane areas, with important implications for ecosystem function.

  3. PREPARATION OF URANIUM HEXAFLUORIDE

    DOEpatents

    Lawroski, S.; Jonke, A.A.; Steunenberg, R.K.

    1959-10-01

    A process is described for preparing uranium hexafluoride from carbonate- leach uranium ore concentrate. The briquetted, crushed, and screened concentrate is reacted with hydrogen fluoride in a fluidized bed, and the uranium tetrafluoride formed is mixed with a solid diluent, such as calcium fluoride. This mixture is fluorinated with fluorine and an inert diluent gas, also in a fluidized bed, and the uranium hexafluoride obtained is finally purified by fractional distillation.

  4. Effects of temperature, concentration, and uranium chloride mixture on zirconium electrochemical studies in LiClsbnd KCl eutectic salt

    NASA Astrophysics Data System (ADS)

    Hoover, Robert O.; Yoon, Dalsung; Phongikaroon, Supathorn

    2016-08-01

    Experimental studies were performed to provide measurement and analysis of zirconium (Zr) electrochemistry in LiClsbnd KCl eutectic salt at different temperatures and concentrations using cyclic voltammetry (CV). An additional experimental set with uranium chloride added into the system forming UCl3sbnd ZrCl4sbnd LiClsbnd KCl was performed to explore the general behavior of these two species together. Results of CV experiments with ZrCl4 show complicated cathodic and anodic peaks, which were identified along with the Zr reactions. The CV results reveal that diffusion coefficients (D) of ZrCl4 and ZrCl2 as the function of temperature can be expressed as DZr(IV) = 0.00046exp(-3716/T) and DZr(II) = 0.027exp(-5617/T), respectively. The standard rate constants and apparent standard potentials of ZrCl4 at different temperatures were calculated. Furthermore, the results from the mixture of UCl3 and ZrCl4 indicate that high concentrations of UCl3 hide the features of the smaller concentration of ZrCl4 while Zr peaks become prominent as the concentration of ZrCl4 increases.

  5. Bioremediation of uranium contamination with enzymatic uranium reduction

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.

    1992-01-01

    Enzymatic uranium reduction by Desulfovibrio desulfuricans readily removed uranium from solution in a batch system or when D. desulfuricans was separated from the bulk of the uranium-containing water by a semipermeable membrane. Uranium reduction continued at concentrations as high as 24 mM. Of a variety of potentially inhibiting anions and metals evaluated, only high concentrations of copper inhibited uranium reduction. Freeze-dried cells, stored aerobically, reduced uranium as fast as fresh cells. D. desulfuricans reduced uranium in pH 4 and pH 7.4 mine drainage waters and in uraniumcontaining groundwaters from a contaminated Department of Energy site. Enzymatic uranium reduction has several potential advantages over other bioprocessing techniques for uranium removal, the most important of which are as follows: the ability to precipitate uranium that is in the form of a uranyl carbonate complex; high capacity for uranium removal per cell; the formation of a compact, relatively pure, uranium precipitate.

  6. Concentrations of heavy metals and plant nutrients in water, sediments and aquatic macrophytes of anthropogenic lakes (former open cut brown coal mines) differing in stage of acidification.

    PubMed

    Samecka-Cymerman, A; Kempers, A J

    2001-12-17

    Concentration of heavy metals (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V and Zn) as well as macronutrients (N, P, K, Ca, Mg, S) were measured in water, bottom sediments and plants from anthropogenic lakes in West Poland. The collected plants were: Phragmites australis, Potamogeton natans, Iris pseudoacorus, Juncus effusus, Drepanocladus aduncus, Juncus bulbosus, Phalaris arundinacea, Carex remota and Calamagrostis epigeios. Two reference lakes were sampled for Nymphaea alba, Phragmites australis, Schoenoplectus lacustris, Typha angustifolia and Polygonum hydropiper. These plants contained elevated levels of Cd, Co, Cr, Cu and Mn, and part of the plants contained in addition elevated levels of Mn, Fe, Pb, Ni and Zn. Analyses of water indicated pollution with sulfates, Cd, Co, Ni. Zn, Pb and Cu, and bottom sediments indicated that some of the examined lakes were polluted with Cd, Co and Cr. Strong positive correlations were found between concentrations of Co in water and in plants and between Zn in sediments and plants, indicating the potential of plants for pollution monitoring for this metal. Heavy metal accumulation seemed to be directly associated with the exclusion of Ca and Mg.

  7. Heavy Metals Concentrations in top Soils of Urban Areas (Naples - Southern Italy) as an Indicator of Anthropogenic Origin.

    NASA Astrophysics Data System (ADS)

    Cicchella, D.; De Vivo, B.; Lima, A.; Somma, R.

    2001-12-01

    Heavy metals pollution, which mainly originates from automobile exhausts and industry, is a serious danger for human health. The source and extension of heavy metals pollution in the top soils has been studied extensively in the past 30 years. The role of the soil processes in accumulating or mobilising metals is very important in environmental science due to the central position of the soil in the hydrological cycle and ecosystem. Concentrations of heavy metals in top soils, collected in green areas and public parks in metropolitan Naples area have been determined to provide information on specific emission sources. In addition to toxic metals, such as Pb, As, Cd, Cr and others, we have investigated the top soils as well for Pt group elements (PGEs), because since 1993 it is mandatory within EC for all new petrol driven motor vehicles to be equipped with Pt/Pd/Rh catalytic converter. In Italy this law has come into effect in 1998, but still is allowed to old vehicles use lead gasoline, though now the big majority of cars is equipped with Pt/Pd/Rh catalytic converters. Emission of abraded fragments of catalytic converters in vehicle exhausts will certainly determine environmental contamination with Pt group elements (PGEs), since many Pt complexes are highly cytotoxic and, in small dose, are strong allergens and potent sensitiser. The metropolitan area of Naples due to intense human activities and vehicles traffic is an interesting area to be monitored in order to check the pollution state of the soils. The geology of the area is prevalently represented by volcanics, erupted from the Upper Pleistocene to Recent by Mt. Somma-Vesuvius on the east and the Campi Flegrei fields on the west. To compile multi-element geochemical maps baseline we have sampled in situ and transported top soil for a total of 200 samples. The survey have been carried at about 200 sites covering an area of about 120 Km2, with a grid of 0.5 x 0.5 km in the highly urbanised area and 1 km x 1 km

  8. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Elk City NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    SciTech Connect

    Broxton, D.E.; Beyth, M.

    1980-07-01

    Totals of 1580 water and 1720 sediment samples were collected from 1754 locations in the quadrangle. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in Appendix I-A and for sediments in Appendix I-B. Uranium/thorium ratios for sediment samples are also included in Appendix I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 parts per billion (ppB) uranium were reanalyzed by delayed-neutron counting (DNC). A supplemental report containing the multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, selenium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc, and zirconium. Basic statistics for 40 of these elements are presented. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million.

  9. Determination of plutonium-239, thorium-232, and natural uranium isotopic concentrations in biological samples using photofission track analysis

    NASA Astrophysics Data System (ADS)

    Parry, James Roswell

    Fission track analysis (FTA) has many uses in the scientific community including but not limited to geological dating, neutron flux mapping, and dose reconstruction. The common method of fission for FTA is through neutrons from a nuclear reactor. This dissertation investigates the use of bremsstrahlung radiation produced from an electron linear accelerator to induce fission in FTA samples. This provides a means of simultaneously measuring the amount of Pu-239, U-nat, and Th-232 in a single sample. The benefit of measuring the three isotopes simultaneously is the possible elimination of costly and time consuming chemical processing for dose reconstruction samples. Samples containing the three isotopes were irradiated in two different bremsstrahlung spectra and a neutron spectrum to determine the amount of Pu-239, U-nat, and Th-232 in the samples. The reaction rate from the calibration samples and the counted fission tracks on the samples were used in determining the concentration of each isotope in the samples. The results were accurate to within a factor of two or three, showing that the method can work to predict the concentrations of multiple isotopes in a sample. The limitations of current accelerators and detectors limits the application of this specific procedure to higher concentrations of isotopes. The method detection limits for Pu-239, U-nat, and Th-232 are 20 pCi, 1 fCi, and 0.4 flCI respectively. Analysis of extremely low concentrations of isotopes would require the use of different detectors such as quartz due to the embrittlement encountered in the Lexan at high exposures. Cracking of the Texan detectors started to appear at a fluence of about 2 x 1018 electrons from the accelerator. This may be partly due to the beam stop not being an adequate thickness. The procedure is likely limited to specialty applications for the near term. However, with the world concerns of exposure to depleted uranium, this procedure may find applications in this area since

  10. Airborne observed and receptor-oriented modelled urban increments of anthropogenic CO2, CO and NOX concentrations in the megacity of London in summer 2012

    NASA Astrophysics Data System (ADS)

    Font Font, Anna Maria; Morguí, Josep Anton; Lee, James; McQuaid, Jim B.; Barratt, Benjamin

    2014-05-01

    A better characterization of the emissions and the dynamics of anthropogenic CO2 in large-urban centres are needed to implement more effective mitigation measures to combat climate change. This study aims to establish a representative emissions ratio of anthropogenic CO2 (CO2ff) in the megacity of London using CO and NOX as tracers. Observations of CO2, CO and NOX mixing ratios obtained onboard the NERC-ARSF aircraft undertaken on 12 July 2012 over the city of London were used. Airborne observations were taken at ~380 m along four transects crossing London, two in the morning (10:30 to 12:30 GMT) and two in the afternoon (15:30-16:30 GMT). The ratio of the amounts of CO and CO2 in excess of natural abundances (denoted as ΔCO and ΔCO2, respectively) from the airborne observations was used to determine the fraction of CO2 derived from burning fossil fuels (CO2ff). Total observations of CO and CO2 were compared to NOX observations and background concentrations were determined as the intercept when NOX mixing ratios equalled zero derived from standardised major axis linear regression. Excess concentrations were calculated by subtracting total amounts minus the background. ΔCO showed good correlation with ΔCO2 in the morning transects (R=0.95) but not in the afternoon (R=-0.50). The mean (±1σ) CO/CO2ff was derived from linear regression using the morning measurements and valued 5.0±0.4 ppb ppm-1. Lagrangian Particle Dispersion (LPD) simulations in backward mode were undertaken to model urban increments of anthropogenic CO2 and CO and to calculate the emissions ratio from the emissions inventory EDGAR v4.2. The LPD model FLEXPART was run with the meteorological data from the European Centre for Medium-Range Weather Forecasts (spatial resolution of 0.2 x 0.2 degrees; 91 vertical levels) and multiplied with the EDGAR emissions inventory (spatial resolution 0.1 x 0.1 degrees) to obtain an increment at each receptor point along the transects. Annual and temporal

  11. The soil organic carbon content of anthropogenically altered organic soils effects the dissolved organic matter quality, but not the dissolved organic carbon concentrations

    NASA Astrophysics Data System (ADS)

    Frank, Stefan; Tiemeyer, Bärbel; Bechtold, Michel; Lücke, Andreas; Bol, Roland

    2016-04-01

    Dissolved organic carbon (DOC) is an important link between terrestrial and aquatic ecosystems. This is especially true for peatlands which usually show high concentrations of DOC due to the high stocks of soil organic carbon (SOC). Most previous studies found that DOC concentrations in the soil solution depend on the SOC content. Thus, one would expect low DOC concentrations in peatlands which have anthropogenically been altered by mixing with sand. Here, we want to show the effect of SOC and groundwater level on the quantity and quality of the dissolved organic matter (DOM). Three sampling sites were installed in a strongly disturbed bog. Two sites differ in SOC (Site A: 48%, Site B: 9%) but show the same mean annual groundwater level of 15 and 18 cm below ground, respectively. The SOC content of site C (11%) is similar to Site B, but the groundwater level is much lower (-31 cm) than at the other two sites. All sites have a similar depth of the organic horizon (30 cm) and the same land-use (low-intensity sheep grazing). Over two years, the soil solution was sampled bi-weekly in three depths (15, 30 and 60 cm) and three replicates. All samples were analyzed for DOC and selected samples for dissolved organic nitrogen (DON) and delta-13C and delta-15N. Despite differences in SOC and groundwater level, DOC concentrations did not differ significantly (A: 192 ± 62 mg/L, B: 163 ± 55 mg/L and C: 191 ± 97 mg/L). At all sites, DOC concentrations exceed typical values for peatlands by far and emphasize the relevance even of strongly disturbed organic soils for DOC losses. Individual DOC concentrations were controlled by the temperature and the groundwater level over the preceding weeks. Differences in DOM quality were clearer. At site B with a low SOC content, the DOC:DON ratio of the soil solution equals the soil's C:N ratio, but the DOC:DON ratio is much higher than the C:N ratio at site A. In all cases, the DOC:DON ratio strongly correlates with delta-13C. There is no

  12. Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan.

    PubMed

    Abusini, M; Al-Ayasreh, K; Al-Jundi, J

    2008-01-01

    Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean activity concentration for (238)U, (232)Th and (40)K was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of (238)U, (232)Th and (40)K in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al(2)O(3), SiO(2), K(2)O, CaO and Fe(2)O(3)) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.

  13. PROCESS OF PURIFYING URANIUM

    DOEpatents

    Seaborg, G.T.; Orlemann, E.F.; Jensen, L.H.

    1958-12-23

    A method of obtaining substantially pure uranium from a uranium composition contaminated with light element impurities such as sodium, magnesium, beryllium, and the like is described. An acidic aqueous solution containing tetravalent uranium is treated with a soluble molybdate to form insoluble uranous molybdate which is removed. This material after washing is dissolved in concentrated nitric acid to obtaln a uranyl nitrate solution from which highly purified uranium is obtained by extraction with ether.

  14. Uranium industry annual 1998

    SciTech Connect

    1999-04-22

    The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers convenience, metric versions of selected tables from Chapters 1 and 2 are presented in Appendix E along with the standard conversion factors used. A glossary of technical terms is at the end of the report. 24 figs., 56 tabs.

  15. Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain

    SciTech Connect

    Bolivar, J. P.; Olias, M.; Gonzalez-Garcia, F.; Garcia-Tenorio, R.

    2008-08-07

    The levels and distribution of natural radionuclides in groundwaters from the unconfined Almonte-Marismas aquifer, upon which Donana National Park is located, have been analysed. Most sampled points were multiple piezometers trying to study the vertical distribution of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, physico-chemical properties, major and minor ions, trace elements and natural radionuclides (U-isotopes, Th-isotopes, Ra-isotopes and {sup 210}Po), were also analysed. In the southern zone, where aeolian sands crop out, water composition is of the sodium chloride type, and the lower U-isotopes concentrations have been obtained. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly, and higher radionuclides concentrations were measured. Finally, we have demonstrated that {sup 234}U/{sup 238}U activity ratios can be used as markers of the type of groundwater and bedrock, as it has been the case for old waters with marine origin confined by a marsh in the south-east part of aquifer.

  16. Arsenic speciation and uranium concentrations in drinking water supply wells in Northern Greece: correlations with redox indicative parameters and implications for groundwater treatment.

    PubMed

    Katsoyiannis, Ioannis A; Hug, Stephan J; Ammann, Adrian; Zikoudi, Antonia; Hatziliontos, Christodoulos

    2007-09-20

    The cities in the Aksios and Kalikratia areas in Northern Greece rely on arsenic contaminated groundwater for their municipal water supply. As remedial action strongly depends on arsenic speciation, the presence of other possible contaminants, and on the general water composition, a detailed study with samples from 21 representative locations was undertaken. Arsenic concentrations were typically 10-70 microg/L. In the groundwaters of the Aksios area with lower Eh values (87-172 mV), pH 7.5-8.2 and 4-6 mM HCO(3) alkalinity, As(III) predominated. Manganese concentrations were mostly above the EC standard of 0.05 mg/L (0.1-0.7 mg/L). In groundwaters of the Kalikratia area with higher Eh values (272-352 mV), pH 6.7-7.5 and 6-12 mM HCO(3) alkalinity, As(V) was the main species. Uranium in the groundwaters was also investigated and correlations with total arsenic concentrations and speciation were examined to understand more of the redox chemistry of the examined groundwaters. Uranium concentrations were in the range 0.01-10 microg/L, with the higher concentrations to occur in the oxidizing groundwaters of the Kalikratia area. Uranium and total arsenic concentrations showed no correlation, whereas uranium concentrations correlated strongly with As(III)/As(tot) ratios, depicting their use as a possible indicator of groundwater redox conditions. Finally, boron was found to exceed the EC drinking water standard of 1 mg/L in some wells in the Kalikratia area and its removal should also be considered in the design of a remedial action.

  17. Arsenic, iron, lead, manganese, and uranium concentrations in private bedrock wells in southeastern New Hampshire, 2012-2013

    USGS Publications Warehouse

    Flanagan, Sarah M.; Belaval, Marcel; Ayotte, Joseph D.

    2014-01-01

    Trace metals, such as arsenic, iron, lead, manganese, and uranium, in groundwater used for drinking have long been a concern because of the potential adverse effects on human health and the aesthetic or nuisance problems that some present. Moderate to high concentrations of the trace metal arsenic have been identified in drinking water from groundwater sources in southeastern New Hampshire, a rapidly growing region of the State (Montgomery and others, 2003). During the past decade (2000–10), southeastern New Hampshire, which is composed of Hillsborough, Rockingham, and Strafford Counties, has grown in population by nearly 48,700 (or 6.4 percent) to 819,100. These three counties contain 62 percent of the State’s population but encompass only about 22 percent of the land area (New Hampshire Office of Energy and Planning, 2011). According to a 2005 water-use study (Hayes and Horn, 2009), about 39 percent of the population in these three counties in southeastern New Hampshire uses private wells as sources of drinking water, and these wells are not required by the State to be routinely tested for trace metals or other contaminants. Some trace metals have associated human-health benchmarks or nonhealth guidelines that have been established by the U.S. Environmental Protection Agency (EPA) to regulate public water supplies. The EPA has established a maximum contaminant level (MCL) of 10 micrograms per liter (μg/L) for arsenic (As) and a MCL of 30 μg/L for uranium (U) because of associated health risks (U.S. Environmental Protection Agency, 2012). Iron (Fe) and manganese (Mn) are essential for human health, but Mn at high doses may have adverse cognitive effects in children (Bouchard and others, 2011; Agency for Toxic Substances and Disease Registry, 2012); therefore, the EPA has issued a lifetime health advisory (LHA) of 300 μg/L for Mn. Recommended secondary maximum contaminant levels (SMCLs) for Fe (300 μg/L) and Mn (50 μg/L) were established primarily as

  18. Sea to land transfer of anthropogenic radionuclides to the North Wales coast, Part I: external gamma radiation and radionuclide concentrations in intertidal sediments, soil and air.

    PubMed

    Bryan, S E; McDonald, P; Hill, R; Wilson, R C

    2008-01-01

    Previous projects specifically aimed at performing radiological assessments in the vicinity of North Wales, investigating the presence and transfer of radionuclides from sea to land, were in 1986 and 1989. Since then, changes have occurred in the radioactive discharges from the British Nuclear Group Sellafield site. Annual discharges of (137)Cs, (238)Pu, (239,340)Pu and (241)Am have decreased markedly whereas, up until recent years, discharges of (99)Tc have increased. It is therefore desirable to quantify current transfer processes of radionuclides in the North Wales region and thus provide an update on 15-year-old studies. A field campaign was conducted collecting soil samples from 10 inland transects and air particulates on air filters from three High Volume Air Samplers, along the northern coast of Wales at Amlwch, Bangor Pier and Flint. Complementary field data relating to external gamma dose rates were collected at the soil sites. The field data generated for (137)Cs, (238)Pu, (239,340)Pu and (241)Am were consistent with what had been reported 15 years previously. Therefore, there has been no increase in the supply of these Sellafield-derived radionuclides to the terrestrial environment of the North Wales coast. The (99)Tc data in sediments were consistent with reported values within annual monitoring programmes, however, a relatively high activity concentration was measured in one sediment sample. This site was further investigated to determine the reason why such a high value was found. At present there is no clear evidence as to why this elevated concentration should be present, but the role of seaweed and its capacity in accumulating (99)Tc and transferring it to sediment is of interest. The analysis of the field samples for (99)Tc, (137)Cs, (238)Pu, (239,240)Pu and (241)Am has provided a data set that can be used for the modelling of the transfer of anthropogenic radionuclides from sea to land and its subsequent radiological implications and is reported

  19. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Dubois NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    SciTech Connect

    LaDelfe, C.M.

    1980-08-01

    Totals of 1024 water samples and 1600 sediment samples were collected from 1669 locations in the Dubois quadrangle. Water samples were taken at streams, springs, and wells; sediment samples were collected from streams and springs. All field and analytical data are presented for waters in Appendix I-A and for sediments in I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than the upper detection limit of uranium were reanalyzed by delayed neutron counting. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium rubidium, samarium, scandium, selenium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc and zirconium. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million.

  20. Uranium hexafluoride public risk

    SciTech Connect

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  1. URANIUM SEPARATION PROCESS

    DOEpatents

    Hyde, E.K.; Katzin, L.I.; Wolf, M.J.

    1959-07-14

    The separation of uranium from a mixture of uranium and thorium by organic solvent extraction from an aqueous solution is described. The uranium is separrted from an aqueous mixture of uranium and thorium nitrates 3 N in nitric acid and containing salting out agents such as ammonium nitrate, so as to bring ihe total nitrate ion concentration to a maximum of about 8 N by contacting the mixture with an immiscible aliphatic oxygen containing organic solvent such as diethyl carbinol, hexone, n-amyl acetate and the like. The uranium values may be recovered from the organic phase by back extraction with water.

  2. Recovery of uranium by a reverse osmosis process

    SciTech Connect

    Cleary, J.G.; Stana, R.R.

    1980-06-03

    A method for concentrating and recovering uranium material from an aqueous solution, comprises passing a feed solution containing uranium through at least one reverse osmosis membrane system to concentrate the uranium, and then flushing the concentrated uranium solution with water in a reverse osmosis membrane system to further concentrate the uranium.

  3. Potential of Melastoma malabathricum as bio-accumulator for uranium and thorium from soil

    SciTech Connect

    Saat, Ahmad; Kamsani, Ain Shaqina; Kamri, Wan Nur Aina Nadzira; Talib, Nur Hasyimah Mat; Wood, Ab Khalik; Hamzah, Zaini

    2015-04-29

    Uranium and Thorium are naturally occuring radionuclides. However, due to anthropogenic activities in some locations their concentrations in the soils could be elevated. This study explores the potential of Melastoma malabathricum (locally known as ‘pokok senduduk’) as bio-accumulator of uranium and thorium from soils of three different study areas, namely former tin mining, industrial and residential/commercial areas in Peninsular Malaysia. The study found elevated concentrations of uranium and thorium in former tin mining soils as compared to natural abundance. However in industral and residential/commercial areas the concentrations are within the range of natural abundance. In terms of transfer factor (TF), in ex-mining areas TF > 1 for uranium in the leaf, stem and roots, indicating accumulation of uranium from soil. However for thorium TF < 1, indicating the occurence of transfer from soil to root, stem and leaf, but no accumulation. For other areas only transfer of uranium and thorium were observed. The results indicated the potential of Melastoma malabathricum to be used as bio-accumulatior of uranium, especially in areas of elevated concentration.

  4. Determination of elemental impurities and U and O isotopic compositions with a view to identify the geographical and industrial origins of uranium ore concentrates

    NASA Astrophysics Data System (ADS)

    Salaun, A.; Hubert, A.; Pointurier, F.; Aupiais, J.; Pili, E.; Richon, P.; Fauré, A.; Diallo, S.

    2012-12-01

    First events of illicit trafficking of nuclear and radiological materials occurred 50 years ago. Nuclear forensics expertise are aiming at determining the use of seized material, its industrial history and provenance (geographical area, place of production or processing), at assisting in the identification and dismantling of illicit trafficking networks. This information is also valuable in the context of inspections of declared facilities to verify the consistency of operator's declaration. Several characteristics can be used to determine the origin of uranium ore concentrates such as trace elemental impurity patterns (Keegan et al., 2008 ; Varga et al., 2010a, 2010b) or uranium, oxygen and lead isotopic compositions (Tamborini et al., 2002a, 2002b ; Wallenius et al., 2006; Varga et al., 2009). We developed analytical procedures for measuring the isotopic compositions of uranium (234U/238U and 235U/238U) and oxygen (18O/16O) and levels of elemental impurities (e.g. REE, Th) from very small amounts of uranium ore concentrates (or yellow cakes). Micrometer particles and few milligrams of material are used for oxygen isotope measurements and REE determination, respectively. Reference materials were analyzed by mass spectrometry (TIMS, SF-ICP-MS and SIMS) to validate testing protocols. Finally, materials of unknown origin were analyzed to highlight significant differences and determine whether these differences allow identifying the origin of these ore concentrates. References: Keegan, E., et al. (2008). Applied Geochemistry 23, 765-777. Tamborini, G., et al. (2002a). Analytical Chemistry 74, 6098-6101. Tamborini, G., et al. (2002b). Microchimica Acta 139, 185-188. Varga, Z., et al. (2009). Analytical Chemistry 81, 8327-8334. Varga, Z., et al. (2010a). Talanta 80, 1744-1749. Varga, Z., et al. (2010b). Radiochimica Acta 98, 771-778 Wallenius, M., et al. (2006). Forensic Science International 156, 55-62.

  5. Human exposure to uranium in groundwater.

    PubMed

    Orloff, Kenneth G; Mistry, Ketna; Charp, Paul; Metcalf, Susan; Marino, Robert; Shelly, Tracy; Melaro, Eric; Donohoe, Ann Marie; Jones, Robert L

    2004-03-01

    High concentrations of uranium (mean=620 microg/L) were detected in water samples collected from private wells in a residential community. Based on isotopic analyses, the source of the uranium contamination appeared to be from naturally occurring geological deposits. In homes where well water concentrations of uranium exceeded the drinking water standard, the residents were advised to use an alternate water source for potable purposes. Several months after the residents had stopped drinking the water, urine samples were collected and tested for uranium. Elevated concentrations of uranium (mean=0.40 microg/g creatinine) were detected in urine samples, and 85 percent of the urine uranium concentrations exceeded the 95th percentile concentration of a national reference population. Urine uranium concentrations were positively correlated with water uranium concentrations, but not with the participants' ages or how long they had been drinking the water. Six months later, a second urine sample was collected and tested for uranium. Urine uranium concentrations decreased in most (63 percent) of the people. In those people with the highest initial urine uranium concentrations, the urine levels decreased an average of 78 percent. However, urine uranium concentrations remained elevated (mean=0.27 microg/g), and 87 percent of the urine uranium concentrations exceeded the 95th percentile concentration of the reference population. The results of this investigation demonstrated that after long-term ingestion of uranium in drinking water, elevated concentrations of uranium in urine could be detected up to 10 months after exposure had stopped.

  6. Determination of trace element concentrations and stable lead, uranium and thorium isotope ratios by quadrupole-ICP-MS in NORM and NORM-polluted sample leachates.

    PubMed

    Mas, J L; Villa, M; Hurtado, S; García-Tenorio, R

    2012-02-29

    This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and 206Pb/207Pb/208Pb, 238U/234U and 232Th/230Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA® extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  7. Concentration Data for Anthropogenic Organic Compounds in Ground Water, Surface Water, and Finished Water of Selected Community Water Systems in the United States, 2002-05

    USGS Publications Warehouse

    Carter, Janet M.; Delzer, Gregory C.; Kingsbury, James A.; Hopple, Jessica A.

    2007-01-01

    The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems (CWSs) in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that is treated and ready to be delivered to consumers. Finished water is collected before entering the distribution system. SWQA studies are conducted in two phases, and the objectives of SWQA studies are twofold: (1) to determine the occurrence and, for rivers, seasonal changes in concentrations of a broad list of anthropogenic organic compounds (AOCs) in aquifers and rivers that have some of the largest withdrawals for drinking-water supply (phase 1), and (2) for those AOCs found to occur most frequently in source water, characterize the extent to which these compounds are present in finished water (phase 2). These objectives were met for SWQA studies by collecting ground-water and surface-water (source) samples and analyzing these samples for 258 AOCs during phase 1. Samples from a subset of wells and surface-water sites located in areas with substantial agricultural production in the watershed were analyzed for 19 additional AOCs, for a total of 277 compounds analyzed for SWQA studies. The 277 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and

  8. Uranium Isotopes in Calcium Carbonate: A Possible Proxy for Paleo-pH and Carbonate Ion Concentration?

    NASA Astrophysics Data System (ADS)

    Chen, X.; Romaniello, S. J.; Herrmann, A. D.; Wasylenki, L. E.; Anbar, A. D.

    2015-12-01

    Natural variations of 238U/235U in marine carbonates are being explored as a paleoredox proxy. However, in order for this proxy to be robust, it is important to understand how pH and alkalinity affect the fractionation of 238U/235U during coprecipitation with calcite and aragonite. Recent work suggests that the U/Ca ratio of foraminiferal calcite may vary with seawater [CO32-] concentration due to changes in U speciation[1]. Here we explore analogous isotopic consequences in inorganic laboratory co-precipitation experiments. Uranium coprecipitation experiments with calcite and aragonite were performed at pH 8.5 ± 0.1 and 7.5 ± 0.1 using a constant addition method [2]. Dissolved U in the remaining solution was periodically collected throughout the experiments. Samples were purified with UTEVA resin and 238U/235U was determined using a 233U-236U double-spike and MC-ICP-MS, attaining a precision of ± 0.10 ‰ [3]. Small but resolvable U isotope fractionation was observed in aragonite experiments at pH ~8.5, preferentially enriching heavier U isotopes in the solid phase. 238U/235U of the dissolved U in these experiments can be fit by Rayleigh fractionation curves with fractionation factors of 1.00002 - 1.00009. In contrast, no resolvable U isotope fractionation was detected in an aragonite experiment at pH ~7.5 or in calcite experiments at either pH. Equilibrium isotope fractionation among dissolved U species is the most likely mechanism driving these isotope effects. Our quantitative model of this process assumes that charged U species are preferentially incorporated into CaCO3 relative to the neutral U species Ca2UO2(CO3)3(aq), which we hypothesize to have a lighter equilibrium U isotope composition than the charged U species. According to this model, the magnitude of U isotope fractionation should scale with the fraction of the neutral U species in the solution, in agreement with our experimental results. These findings suggest that U isotope variations in

  9. Evaluation of sediment quality guidelines derived using the screening-level concentration approach for application at uranium operations in Saskatchewan, Canada.

    PubMed

    Burnett-Seidel, Charlene; Liber, Karsten

    2012-03-01

    Sediment quality guidelines (SQGs) can be derived using different approaches and are commonly used in environmental management, reclamation, and risk assessment. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal and radionuclide concentrations in sediment, and corresponding benthic community composition data for a specific sampling site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan uranium operations were compiled and examined. Results indicate that the CNSC-derived SQGs had limited relationships to observed effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. The LELs were found to correctly align with effects at 95% of the sites that had effects, on a general basis, but on an element-specific basis many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. It is suggested that alternatives to the SLC approach be explored.

  10. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Lewistown NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

    SciTech Connect

    Shannon, S.S. Jr.

    1980-08-01

    Totals of 758 water and 1170 sediment samples were collected from 1649 locations in the Levistown quadrangle. Water samples were collected at streams, springs, wells, ponds, and marshes; sediment samples were obtained from streams, springs, and ponds. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. All samples were collected at the nominal reconnaissance density of one sample location per 10 km/sup 2/. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium to thorium (U/Th) ratios for sediment samples are included. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB U were reanalyzed by delayed-neutron counting. Sediments were analyzed for U and Th as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sa, Sc, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, and Zn. All sediments were analyzed for U by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results are reported as parts per million. Descriptions of procedures used for analysis of water and sediments samples as well as analytical precisions and detection limits are given.

  11. Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate

    SciTech Connect

    Marks, N. E.; Borg, L. E.; Eppich, G. R.; Gaffney, A. M.; Genneti, V. G.; Hutcheon, I. D.; Kristo, M. J.; Lindvall, R. E.; Ramon, C.; Robel, M.; Roberts, S. K.; Schorzman, K. C.; Sharp, M. A.; Singleton, M. J.; Williams, R. W.

    2015-07-09

    The goals of this SP-1 effort were to understand how isotopic and elemental signatures behave during mining, milling, and concentration and to identify analytes that might preserve geologic signatures of the protolith ores. The impurities that are preserved through the concentration process could provide useful forensic signatures and perhaps prove diagnostic of sample origin.

  12. Measurements of natural uranium concentration and isotopic composition with permil-level precision by inductively coupled plasma-quadrupole mass spectrometry

    NASA Astrophysics Data System (ADS)

    Shen, Chuan-Chou; Lin, Huei-Ting; Chu, Mei-Fei; Yu, Ein-Fen; Wang, Xianfeng; Dorale, Jeffrey A.

    2006-09-01

    A new analytical technique using inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) has been developed that produces permil-level precision in the measurement of uranium concentration ([U]) and isotopic composition (δ234U) in natural materials. A 233U-236U double spike method was used to correct for mass fractionation during analysis. To correct for ratio drifting, samples were bracketed by uranium standard measurements. A sensitivity of 6-7 × 108 cps/ppm was generated with a sample solution uptake rate of 30 μL/min. With a measurement time of 15-20 min, standards of 30-ng uranium produced a within-run precision better than 3‰ (±2 R.S.D.) for δ234U and better than 2‰ for [U]. Replicate measurements made on standards show that a between-run reproducibility of 3.5‰ for δ234U and 2‰ for [U] can be achieved. ICP-QMS data of δ234U and [U] in seawater, coral, and speleothem materials are consistent with the data measured by other ICP-MS and TIMS techniques. Advantages of the ICP-QMS method include low cost, easy maintenance, simple instrumental operation, and few sample preparation steps. Sample size requirements are small, such as 10-14 mg of coral material. The results demonstrate that this technique can be applied to natural samples with various matrices.

  13. Structural and biological control of the Cenozoic epithermal uranium concentrations from the Sierra Peña Blanca, Mexico

    NASA Astrophysics Data System (ADS)

    Angiboust, Samuel; Fayek, Mostafa; Power, Ian M.; Camacho, Alfredo; Calas, Georges; Southam, Gordon

    2012-12-01

    Epithermal uranium deposits of the Sierra Peña Blanca are classic examples of volcanic-hosted deposits and have been used as natural analogs for radionuclide migration in volcanic settings. We present a new genetic model that incorporates both geochemical and tectonic features of these deposits, including one of the few documented cases of a geochemical signature of biogenic reducing conditions favoring uranium mineralization in an epithermal deposit. Four tectono-magmatic faulting events affected the volcanic pile. Uranium occurrences are associated with breccia zones at the intersection of fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Focused along breccia zones, these fluids precipitated under reducing conditions several generations of pyrite and uraninite together with kaolinite. Oxygen isotopic data indicate a low formation temperature of uraninite, 45-55°C for the uraninite from the ore body and ˜20°C for late uraninite hosted by the underlying conglomerate. There is geochemical evidence for biological activity being at the origin of these reducing conditions, as shown by low δ34S values (˜-24.5‰) in pyrites and the presence of low δ13C (˜-24‰) values in microbial patches intimately associated with uraninite. These data show that tectonic activity coupled with microbial activity can play a major role in the formation of epithermal uranium deposits in unusual near-surface environments.

  14. Uranium in Hanford Site 300 Area: Extraction Data on Borehole Sediments

    SciTech Connect

    Wang, Guohui; Serne, R. Jeffrey; Lindberg, Michael J.; Um, Wooyong; Bjornstad, Bruce N.; Williams, Benjamin D.; Kutynakov, I. V.; Wang, Zheming; Qafoku, Nikolla

    2012-11-26

    In this study, sediments collected from boreholes drilled in 2010 and 2011 as part of a remedial investigation/feasibility study were characterized. The wells, located within or around two process ponds and one process trench waste site, were characterized in terms of total uranium concentration, mobile fraction of uranium, particle size, and moisture content along the borehole depth. In general, the gravel-dominated sediments of the vadose zone Hanford formation in all investigated boreholes had low moisture contents. Based on total uranium content, a total of 48 vadose zone and periodically rewetted zone sediment samples were selected for more detailed characterization, including measuring the concentration of uranium extracted with 8 M nitric acid, and leached using bicarbonate mixed solutions to determine the liable uranium (U(VI)) contents. In addition, water extraction was conducted on 17 selected sediments. Results from the sediment acid and bicarbonate extractions indicated the total concentrations of anthropogenic labile uranium in the sediments varied among the investigated boreholes. The peak uranium concentration (114.84 µg/g, acid extract) in <2-mm size fractions was found in borehole 399 1-55, which was drilled directly in the southwest corner of the North Process Pond. Lower uranium concentrations (~0.3–2.5 µg/g, acid extract) in <2-mm size fractions were found in boreholes 399-1-57, 399-1-58, and 399-1-59, which were drilled either near the Columbia River or inland and upgradient of any waste process ponds or trenches. A general trend of “total” uranium concentrations was observed that increased as the particle size decreased when relating the sediment particle size and acid extractable uranium concentrations in two selected sediment samples. The labile uranium bicarbonate leaching kinetic experiments on three selected sediments indicated a two-step leaching rate: an initial rapid release, followed by a slow continual release of uranium from

  15. Uranium in stream and mineral water of the Federal Republic of Germany.

    PubMed

    Birke, Manfred; Rauch, Uwe; Lorenz, Hans

    2009-12-01

    The concentration of uranium was determined in 944 samples from stream water by the inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) method and represented on a color-shaded contour map. Uranium concentrations in surface water were determined to be between 0.007 μg/l and 43.7 μg/l with median of 0.33 μg/l. The regional distribution of uranium is influenced primarily by lithological and anthropogenic factors. In Mecklenburg, northern Brandenburg, and eastern Schleswig-Holstein, elevated uranium concentrations coincide with the extent of the last Weichselian ice sheet. The maximum concentrations are observed in the surface waters of the old mining districts in the western part of the Ore Mountains and in eastern Thuringia. Elevated concentrations are found in areas of agriculturally used loess soils. These concentrations correlate with the use of phosphate fertilizers. There is a zone of elevated concentrations up to 10.0 μg U/l in the Keuper Sandstone area south of the Thuringian Forest and from northwest of Stuttgart as far as Coburg. The distribution of elevated values in mineral water shows a clear correlation with the elevated values in surface water and the geology of those locations. Bunter and Keuper strata are the most important uranium source.

  16. The Concentration and Distribution of Depleted Uranium (DU) and Beryllium (Be) in Soil and Air on Illeginni Island at Kwajalein Atoll

    SciTech Connect

    Robison, W L; Hamilton, T F; Martinelli, R E; Gouveia, F J; Lindman, T R; Yakuma, S C

    2006-04-27

    Re-entry vehicles on missiles launched at Vandenberg Air Force base in California re-enter at the Western Test Range, the Regan Test Site (RTS) at Kwajalein Atoll. An environmental Assessment (EA) was written at the beginning of the program to assess potential impact of Depleted Uranium (DU) and Beryllium (Be), the major RV materials of interest from a health and environmental perspective. The chemical and structural form of DU and Be in RVs is such that they are insoluble in soil water and sea water. Consequently, residual concentrations of DU and Be observed in soil on the island are not expected to be toxic to plant life because there is essentially no soil to plant uptake. Similarly, due to their insolubility in sea water there is no uptake of either element by marine biota including fish, mollusks, shellfish and sea mammals. No increase in either element has been observed in sea life around Illeginni Island where deposition of DU and Be has occurred. The critical terrestrial exposure pathway for U and Be is inhalation. Concentration of both elements in air over the test period (1989 to 2006) is lower by a factor of 10,000 than the most restrictive U.S. guideline for the general public. Uranium concentrations in air are also lower by factors of 10 to 100 than concentrations of U in air in the U.S. measured by the EPA (Keith et al., 1999). U and Be concentrations in air downwind of deposition areas on Illeginni Island are essentially indistinguishable from natural background concentrations of U in air at the atolls. Thus, there are no health related issues associated with people using the island.

  17. Anthropogenic climate change

    SciTech Connect

    Budyko, M.I.; Izreal, Yu.A.

    1991-01-01

    The climate modeling community would agree that the present generation of theoretical models cannot adequately answer important question about the climatic implications of increasing concentrations of CO[sub 2] and other greenhouse gases. Society, however, is presently deciding by its action, or inaction, the policies that will deal with the extent and results of our collective flatulence. In this situation, an engineering approach to estimating the developing pattern of anthropogenic climate change is appropriate. For example, Budyko has argued that, while scientists may have made great advances in modelling the flow around an airfoil, engineers make extensive use of empirical equations and measurements to design airplanes that fly. Budyko and Izreal have produced an encyclopedic treatise summarizing the results of Soviet researchers in applying empirical and semiempirical methods to estimating future climatic patterns, and some of their ensuring effects. These techniques consist mainly of statistical relationships derived from 1850-1950 network data and of patterns revealed by analysis of paleoclimatic data. An important part of the Soviet effort in anthropogenic climate-change studies is empirical techniques that represent independent verification of the results of theoretical climate models.

  18. Intra- and inter-annual uranium concentration variability in a Belizean stalagmite controlled by prior aragonite precipitation: A new tool for reconstructing hydro-climate using aragonitic speleothems

    NASA Astrophysics Data System (ADS)

    Jamieson, Robert A.; Baldini, James U. L.; Brett, Marianne J.; Taylor, Jessica; Ridley, Harriet E.; Ottley, Chris J.; Prufer, Keith M.; Wassenburg, Jasper A.; Scholz, Denis; Breitenbach, Sebastian F. M.

    2016-10-01

    Aragonitic speleothems are increasingly utilised as palaeoclimate archives due to their amenability to high precision U-Th dating. Proxy records from fast-growing aragonitic stalagmites, precisely dated to annual timescales, can allow investigation of climatic events occurring on annual or even sub-annual timescales with minimal chronological uncertainty. However, the behaviour of many trace elements, such as uranium, in aragonitic speleothems has not thus far been as well constrained as in calcitic speleothems. Here, we use uranium concentration shifts measured across primary calcite-to-aragonite mineralogical transitions in speleothems to calculate the distribution coefficient of uranium in aragonitic speleothems (derived DU = 3.74 ± 1.13). Because our calculated DU is considerably above 1 increased prior aragonite precipitation due to increased karst water residence time should strongly control stalagmite aragonite U/Ca values. Consequently, uranium concentrations in aragonitic speleothems should act as excellent proxies for effective rainfall. We test this using a high-resolution ICP-MS derived trace element dataset from a Belizean stalagmite. YOK-G is an aragonitic stalagmite from Yok Balum cave in Belize with an extremely robust monthly-resolved chronology built using annual δ13C cycles. We interpret seasonal U/Ca variations in YOK-G as reflecting changes in the amount and seasonality of prior aragonite precipitation driven by variable rainfall amounts. The U/Ca record strongly suggests that modern drying has occurred in Belize, and that this drying was primarily caused by a reduction in wet season rainfall. This is consistent with published stable isotope data from YOK-G also very strongly suggesting modern rainfall reductions, previously interpreted as the result of southward ITCZ displacement. Our results strongly suggest that U/Ca values in aragonitic speleothems are excellent proxies for rainfall variability. This new tool, combined with the

  19. Exact Solution of Fractional Diffusion Model with Source Term used in Study of Concentration of Fission Product in Uranium Dioxide Particle

    NASA Astrophysics Data System (ADS)

    Fang, Chao; Cao, Jian-Zhu; Sun, Li-Feng

    2011-05-01

    The exact solution of fractional diffusion model with a location-independent source term used in the study of the concentration of fission product in spherical uranium dioxide (UO2) particle is built. The adsorption effect of the fission product on the surface of the UO2 particle and the delayed decay effect are also considered. The solution is given in terms of Mittag—Leffler function with finite Hankel integral transformation and Laplace transformation. At last, the reduced forms of the solution under some special physical conditions, which is used in nuclear engineering, are obtained and corresponding remarks are given to provide significant exact results to the concentration analysis of nuclear fission products in nuclear reactor.

  20. Discrimination of source reactor type by multivariate statistical analysis of uranium and plutonium isotopic concentrations in unknown irradiated nuclear fuel material.

    PubMed

    Robel, Martin; Kristo, Michael J

    2008-11-01

    The problem of identifying the provenance of unknown nuclear material in the environment by multivariate statistical analysis of its uranium and/or plutonium isotopic composition is considered. Such material can be introduced into the environment as a result of nuclear accidents, inadvertent processing losses, illegal dumping of waste, or deliberate trafficking in nuclear materials. Various combinations of reactor type and fuel composition were analyzed using Principal Components Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLSDA) of the concentrations of nine U and Pu isotopes in fuel as a function of burnup. Real-world variation in the concentrations of (234)U and (236)U in the fresh (unirradiated) fuel was incorporated. The U and Pu were also analyzed separately, with results that suggest that, even after reprocessing or environmental fractionation, Pu isotopes can be used to determine both the source reactor type and the initial fuel composition with good discrimination.

  1. Influence of biomass burning and anthropogenic emissions on ozone, carbon monoxide and black carbon concentrations at the Mt. Cimone GAW-WMO global station (Italy, 2165 m a.s.l.)

    NASA Astrophysics Data System (ADS)

    Cristofanelli, P.; Fierli, F.; Marinoni, A.; Duchi, R.; Burkhart, J.; Stohl, A.; Maione, M.; Arduini, J.; Bonasoni, P.

    2012-08-01

    This work investigates the variability of ozone (O3), carbon monoxide (CO) and equivalent black carbon (BC) concentrations at the Italian Climate Observatory "O. Vittori" (ICO-OV), part of the Mt. Cimone global GAW-WMO station (Italy). For this purpose, ICO-OV observations carried out in the period January 2007-June 2009, have been analysed and correlated with the output of the FLEXPART Lagrangian dispersion model to specifically evaluate the influence of biomass burning (BB) and anthropogenic emissions younger than 20 days. During the investigation period, the average O3, CO and BC concentrations at ICO-OV were 54 ± 3 ppbv, 122 ± 7 ppbv and 213 ± 34 ng m-3 (mean ± expanded uncertainty with p<95%), with clear seasonal cycles characterized by summer maxima and winter minima for O3 and BC and spring maximum and summer minimum for CO. According to FLEXPART output, BB impact is maximized during the warm months from July to September but appeared to have a significant contribution to the observed tracer concentrations only during specific transport events. We characterised in detail five major events with respect to transport scales (i.e. global, regional and local), source regions and O3, CO and BC variations. For these events, very large variability of enhancement ratios O3/CO (from -0.22 to 0.71) and BC/CO (from 2.69 to 29.83 ng m-3 ppbv-1) were observed. CO related with anthropogenic emissions (COant) contributed to 17.4% of the mean CO value observed at ICO-OV, with the warm months appearing particularly affected by transport events of air-masses rich in anthropogenic pollution. The proportion of tracer variability that is described by FLEXPART COant peaked to 37% (in May-September) for CO, 19% (in May-September) for O3 and 32% (in January-April) for BC. During May-September, the analysis of the correlation among CO, O3 and BC as a function of the COant indicated that ICO-OV was influenced by air-masses rich in anthropogenic pollution transported from the

  2. Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10

    USGS Publications Warehouse

    Carter, Janet M.; Kingsbury, James A.; Hopple, Jessica A.; Delzer, Gregory C.

    2010-01-01

    The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected at the supply well before water treatment (for groundwater) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that has been treated and is ready to be delivered to consumers. Finished-water samples are collected before the water enters the distribution system. The primary objective of SWQAs is to determine the occurrence of more than 250 anthropogenic organic compounds in source water used by community water systems, many of which currently are unregulated in drinking water by the U.S. Environmental Protection Agency. A secondary objective is to understand recurrence patterns in source water and determine if these patterns also occur in finished water before distribution. SWQA studies were conducted in two phases for most studies completed by 2005, and in one phase for most studies completed since 2005. Analytical results are reported for a total of 295 different anthropogenic organic compounds monitored in source-water and finished-water samples collected during 2002-10. The 295 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and combustion-derived compounds; (10) personal-care and domestic-use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and

  3. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno (Sudety Mts., SW Poland).

    PubMed

    Fijałkowska-Lichwa, Lidia

    2014-09-01

    Short-term (222)Rn activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno were studied, based on continuous measurements conducted between 16 May 2008 and 15 May 2010. The results were analysed in the context of numbers of visitors arriving at the facility in particular seasons and the time per day spent inside by staff and visitors. This choice was based on partially published earlier findings (Fijałkowska-Lichwa and Przylibski, 2011). Results for the year 2009 were analysed in depth, because it is the only period of observation covering a full calendar year. The year 2009 was also chosen for detailed analysis of short-term radon concentration changes, because in each period of this year (hour, month, season) fluctuations of noted values were the most visible. Attention has been paid to three crucial issues linked to the occurrence and behaviour of radon and to the radiological protection of workers and visitors at the tourist route in Kletno. The object of study is a complex of workings in a former uranium mine situated within a metamorphic rock complex in the most radon-prone area in Poland. The facility has been equipped with a mechanical ventilation system, which is turned on after the closing time and at the end of the working day for the visitor service staff, i.e. after 6 p.m. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno are related to the activity of the facility's mechanical ventilation. Its inactivity in the daytime results in the fact that the highest values of (222)Rn activity concentration are observed at the time when the facility is open to visitors, i.e. between 10 a.m. and 6 p.m. The improper usage of the mechanical ventilation system is responsible for the extremely unfavourable working conditions, which persist in the facility for practically all year. The absence of appropriate radiological protection

  4. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno (Sudety Mts., SW Poland).

    PubMed

    Fijałkowska-Lichwa, Lidia

    2014-09-01

    Short-term (222)Rn activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno were studied, based on continuous measurements conducted between 16 May 2008 and 15 May 2010. The results were analysed in the context of numbers of visitors arriving at the facility in particular seasons and the time per day spent inside by staff and visitors. This choice was based on partially published earlier findings (Fijałkowska-Lichwa and Przylibski, 2011). Results for the year 2009 were analysed in depth, because it is the only period of observation covering a full calendar year. The year 2009 was also chosen for detailed analysis of short-term radon concentration changes, because in each period of this year (hour, month, season) fluctuations of noted values were the most visible. Attention has been paid to three crucial issues linked to the occurrence and behaviour of radon and to the radiological protection of workers and visitors at the tourist route in Kletno. The object of study is a complex of workings in a former uranium mine situated within a metamorphic rock complex in the most radon-prone area in Poland. The facility has been equipped with a mechanical ventilation system, which is turned on after the closing time and at the end of the working day for the visitor service staff, i.e. after 6 p.m. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno are related to the activity of the facility's mechanical ventilation. Its inactivity in the daytime results in the fact that the highest values of (222)Rn activity concentration are observed at the time when the facility is open to visitors, i.e. between 10 a.m. and 6 p.m. The improper usage of the mechanical ventilation system is responsible for the extremely unfavourable working conditions, which persist in the facility for practically all year. The absence of appropriate radiological protection

  5. XAS and TRLIF spectroscopy of uranium and neptunium in seawater.

    PubMed

    Maloubier, Melody; Solari, Pier Lorenzo; Moisy, Philippe; Monfort, Marguerite; Den Auwer, Christophe; Moulin, Christophe

    2015-03-28

    Seawater contains radionuclides at environmental levels; some are naturally present and others come from anthropogenic nuclear activity. In this report, the molecular speciation in seawater of uranium(VI) and neptunium(V) at a concentration of 5 × 10(-5) M has been investigated for the first time using a combination of two spectroscopic techniques: Time-resolved laser-induced fluorescence (TRLIF) for U and extended X-ray absorption fine structure (EXAFS) for U and Np at the LIII edge. In parallel, the theoretical speciation of uranium and neptunium in seawater at the same concentration is also discussed and compared to spectroscopic data. The uranium complex was identified as the neutral carbonato calcic complex UO2(CO3)3Ca2, which has been previously described in other natural systems. In the case of neptunium, the complex identified is mainly a carbonato complex whose exact stoichiometry is more difficult to assess. The knowledge of the actinide molecular speciation and reactivity in seawater is of fundamental interest in the particular case of uranium recovery and more generally regarding the actinide life cycle within the biosphere in the case of accidental release. This is the first report of actinide direct speciation in seawater medium that can complement inventory data.

  6. Characterization of Uranium Contamination, Transport, and Remediation at Rocky Flats - Across Remediation into Post-Closure

    NASA Astrophysics Data System (ADS)

    Janecky, D. R.; Boylan, J.; Murrell, M. T.

    2009-12-01

    The Rocky Flats Site is a former nuclear weapons production facility approximately 16 miles northwest of Denver, Colorado. Built in 1952 and operated by the Atomic Energy Commission and then Department of Energy, the Site was remediated and closed in 2005, and is currently undergoing long-term surveillance and monitoring by the DOE Office of Legacy Management. Areas of contamination resulted from roughly fifty years of operation. Of greatest interest, surface soils were contaminated with plutonium, americium, and uranium; groundwater was contaminated with chlorinated solvents, uranium, and nitrates; and surface waters, as recipients of runoff and shallow groundwater discharge, have been contaminated by transport from both regimes. A region of economic mineralization that has been referred to as the Colorado Mineral Belt is nearby, and the Schwartzwalder uranium mine is approximately five miles upgradient of the Site. Background uranium concentrations are therefore elevated in many areas. Weapons-related activities included work with enriched and depleted uranium, contributing anthropogenic content to the environment. Using high-resolution isotopic analyses, Site-related contamination can be distinguished from natural uranium in water samples. This has been instrumental in defining remedy components, and long-term monitoring and surveillance strategies. Rocky Flats hydrology interlinks surface waters and shallow groundwater (which is very limited in volume and vertical and horizontal extent). Surface water transport pathways include several streams, constructed ponds, and facility surfaces. Shallow groundwater has no demonstrated connection to deep aquifers, and includes natural preferential pathways resulting primarily from porosity in the Rocky Flats alluvium, weathered bedrock, and discontinuous sandstones. In addition, building footings, drains, trenches, and remedial systems provide pathways for transport at the site. Removal of impermeable surfaces (buildings

  7. REE, Uranium (U) and Thorium (Th) contents in Betula pendula leaf growing around Komsomolsk gold concentration plant tailing (Kemerovo region, Western Siberia, Russia)

    NASA Astrophysics Data System (ADS)

    Yusupov, D. V.; Karpenko, Yu A.

    2016-09-01

    The article deals with the research findings of peculiarities of REE, Uranium and Thorium distribution in the territory surrounding the tailing of former Komsomolsk gold concentration plant according to the data from Betula pendula leaf testing. In the leaf element composition the slight deficiency of MREE and substantial excess of HREE are presented. In the nearest impacted area around the tailing, La, Yb, U and Th content, and Th/U ratio are lower than in the distant buffer area. It is shown, that value of Th/U ratio and REE can be an indicator for geochemical transformations of technogenic landscapes in mining districts. The results of the research can be used for biomonitoring of the territory around the tailing.

  8. High resolution analysis of uranium and thorium concentration as well as U-series isotope distributions in a Neanderthal tooth from Payre (Ardèche, France) using laser ablation ICP-MS

    NASA Astrophysics Data System (ADS)

    Grün, Rainer; Aubert, Maxime; Joannes-Boyau, Renaud; Moncel, Marie-Hélène

    2008-11-01

    We have mapped U ( 238U) and Th ( 232Th) elemental concentrations as well as U-series isotope distributions in a Neanderthal tooth from the Middle Palaeolithic site of Payre using laser ablation ICP-MS. The U-concentrations in an enamel section varied between 1 and 1500 ppb. The U-concentration maps show that U-migration through the external enamel surface is minute, the bulk of the uranium having migrated internally via the dentine into the enamel. The uranium migration and uptake is critically dependent on the mineralogical structure of the enamel. Increased U-concentrations are observed along lineaments, some of which are associated with cracks, and others may be related to intra-prismatic zones or structural weaknesses reaching from the dentine into the enamel. The uranium concentrations in the dentine vary between about 25,000 and 45,000 ppb. Our systematic mapping of U-concentration and U-series isotopes provides insight into the time domain of U-accumulation. Most of the uranium was accumulated in an early stage of burial, with some much later overprints. None of the uranium concentration and U-series profiles across the root of the tooth complied with a single stage diffusion-adsorption (D-A) model that is used for quality control in U-series dating of bones and teeth. Nevertheless, in the domains that yielded the oldest apparent U-series age estimates, U-leaching could be excluded. This means that the oldest apparent U-series ages of around 200 ka represent a minimum age for this Neanderthal specimen. This is in good agreement with independent age assessments (200-230 ka) for the archaeological layer, in which it was found. The Th elemental concentrations in the dental tissues were generally low (between about 1 and 20 ppb), and show little relationship with the nature of the tissue.

  9. Anthropogenic Osmium in Precipitation

    NASA Astrophysics Data System (ADS)

    Chen, C.; Sedwick, P. N.; Sharma, M.

    2007-12-01

    Here we report the Os isotopic composition for precipitation from Hanover (NH), Soda Springs (CA) and the Ross Sea (Antarctica) as determined by negative thermal ionization mass spectrometry. All samples yielded non- radiogenic Os isotopic compositions. Snow and rain samples from Hanover, NH had Os concentrations of 0.8 - 12.2 fg/g (1 fg/g = 1E-15 g/g) and 187Os/188Os from 0.16 - 0.24. Snowpack from the high Sierra Nevada (Central Sierra Snow Laboratory, Soda Springs, CA) yielded Os concentration and isotopic composition of 3.6 fg/g and 0.21, respectively; Antarctic snow deposited above first year pack ice had [Os] = 0.8 fg/g and 187Os/188Os = 0.42. The isotopic ratios indicate that potential natural sources of Os to the atmosphere, such as continental mineral aerosols (187Os/188Os = 1.26) and seawater (187Os/188Os = 1.05) do not contribute bulk of Os to the precipitation. Instead, the isotopic ratios are identical to the platinum ores from the Merensky Reef in the Bushveld Igneous Complex, South Africa and Noril'sk Ni-Cu sulfide deposit associated with the Siberian Flood Basalts, Russia. These two deposits produce greater than 95 percent of the total Pt, Pd and Rh consumed annually primarily by the automotive industry. We infer that anthropogenic Os contribution dominates the isotopic composition of precipitation. The similar and non-radiogenic Os isotopic compositions observed in precipitation from disparate locations suggest that contamination of the troposphere with anthropogenic Os may be global in scale. We think that processing of ore to extract Pt, Pd, and Rh from PGE ores (PGE: group of six closely related elements Os, Ir, Pt, Pd, Rh, and Ru), which involves smelting and converting at high temperature and in the presence of oxygen, releases the volatile, toxic compound OsO4 into the troposphere, where it is mixed and then scavenged by precipitation, thus explaining both the non-radiogenic isotopic composition and the high and variable Os concentrations of

  10. Levels of depleted uranium in Kosovo soils.

    PubMed

    Sansone, U; Stellato, L; Jia, G; Rosamilia, S; Gaudino, S; Barbizzi, S; Belli, M

    2001-01-01

    The United Nations Environment Programme (UNEP) has performed a field survey at 11 sites located in Kosovo, where depleted uranium (DU) ammunitions were used by the North Atlantic Treaty Organization (NATO) during the last Balkans conflict (1999). Soil sampling was performed to assess the spread of DU ground contamination around and within the NATO target sites and the migration of DU along the soil profile. The 234U/238U and 235U/238U activity concentration ratios have been used as an indicator of natural against anthropogenic sources of uranium. The results show that levels of 238U activity concentrations in soils above 100 Bq x kg(-1) can be considered a 'tracer' of the presence of DU in soils. The results also indicate that detectable ground surface contamination by DU is limited to areas within a few metres from localised points of concentrated contamination caused by penetrator impacts. Vertical distribution of DU along the soil profile is measurable up to a depth of 10-20 cm. This latter aspect is of particular relevance for the potential risk of future contamination of groundwater.

  11. Uranium concentrations from an aragonite speleothem as a proxy for Mesoamerican Monsoon Variability over the last 2,250 years

    NASA Astrophysics Data System (ADS)

    Crotty, C.; Lachniet, M. S.; Asmerom, Y.; Polyak, V. J.; Bernal, J. P.

    2015-12-01

    Trace element concentrations (Mg and U) were measured in an aragonite stalagmite (JX-6) from Juxtlahuaca Cave ("JX Cave"), in southwestern Mexico, using an inductively coupled plasma mass spectrometer (ICP-MS). These trace element concentrations were compared to previously analyzed δ18O and δ13C values from JX-6, and to the results of previous studies comparing U concentrations in speleothems to paleoclimate. U concentrations of JX-6 correlate well with δ13C and δ18O values, and we interpret them to be a proxy for soil moisture above Juxtlahuaca Cave. This study concludes that U concentrations in JX-6 may be controlled by changes in the pCO2 of overlying soils in relation to plant respiration possibly linked to the consistency of wet season (May - November) rainfall and temperature between 240 BCE to 1800 CE. Comparison to previous studies suggests that speleothem U concentrations are controlled by local cave conditions and are best used with the support of additional trace element and stable isotope data. Anomalous spikes in trace element concentrations were also observed in JX-6 at ~1862, 1871, 1904, and 1933 CE. These spikes were interpreted to be caused by increased U mobilization in overlying soils related to multiple deforestation events in association with the clearing of land above Juxtlahuaca Cave for agricultural use.

  12. LA-ICP-MS of rare earth elements concentrated in cation-exchange resin particles for origin attribution of uranium ore concentrate.

    PubMed

    Asai, Shiho; Limbeck, Andreas

    2015-04-01

    Rare earth elements (REE) concentrated on cation-exchange resin particles were measured with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to obtain chondrite-normalized REE plots. The sensitivity of REE increased in ascending order of the atomic number, according to the sensitivity trend in pneumatic nebulization ICP-MS (PN-ICP-MS). The signal intensities of REE were nearly proportional to the concentrations of REE in the immersion solution used for particle-preparation. Minimum measurable concentration calculated from the net signals of REE was approximately 1 ng/g corresponding to 0.1 ng in the particle-preparation solution. In LA analysis, formation of oxide and hydroxide of the light REE and Ba which causes spectral interferences in the heavy REE measurement was effectively attenuated due to the solvent-free measurement capability, compared to conventional PN-ICP-MS. To evaluate the applicability of the proposed method, the REE-adsorbed particles prepared by immersing them in a U-bearing solution (commercially available U standard solution) were measured with LA-ICP-MS. Aside from the LA analysis, each concentration of REE in the same U standard solution was determined with conventional PN-ICP-MS after separating REE by cation-exchange chromatography. The concentrations of REE were ranging from 0.04 (Pr) to 1.08 (Dy) μg/g-U. The chondrite-normalized plot obtained through LA-ICP-MS analysis of the U standard sample exhibited close agreement with that obtained through the PN-ICP-MS of the REE-separated solution within the uncertainties.

  13. Changing Nitrate Concentrations in Arid Basin Aquifers- How Anthropogenic and Natural Processes Affect Water Quality and Availability in Trans-Pecos, TX

    NASA Astrophysics Data System (ADS)

    Robertson, W. M.; Bohlke, J. K.; Sharp, J. M.

    2012-12-01

    For the past six decades nitrate concentrations in groundwater of the West Texas Bolson Aquifers have been increasing. Long-term records (from 1950 to present) indicate an average increase of 3-5 mg/L (as nitrate) with some wells increasing by over 40 mg/L within 1-2 decades. While irrigated agriculture is the second largest land use in the region (range land being the largest), isotopic analyses indicate that direct leaching of synthetic fertilizers is not a primary source of nitrate to the groundwater; the isotopic composition of the nitrate in the groundwater (delta 18-O of +2 to +10 per mil and delta 15-N of +6 to +13 per mil) is more similar to that of natural soil-derived nitrate in the region, or possibly manure-derived nitrate. Various anion ratios (chloride/bromide, nitrate/chloride, and nitrate/bromide) provide additional insight into the likely sources of groundwater nitrate and the mechanisms by which it is transported through the unsaturated zone; compared to atmospheric deposition, groundwater N/Cl and N/Br ratios appear to be relatively low, consistent with net N loss accompanied by relatively high delta 15-N of residual N. The observed decadal scale changes in groundwater nitrate concentration and presence of young (<70 year old) recharge (as measured using CFCs) are coincident with the growth of irrigated agriculture and intensive grazing within the basins. We hypothesize that past and present land use practices have contributed to the increase in nitrate in the groundwater in three ways; 1) plowing and grazing of previously undisturbed grasslands led to mobilization of soil nitrogen, 2) irrigation of crops has increased recharge beneath agricultural fields and mobilized naturally occurring nitrate from the unsaturated zone, and 3) deposition of manure by grazing animals may have contributed to high delta 15-N values, and in the case of now disused CAFO operations (confined feed lots) may have contributed locally to the total mass of reactive

  14. Spatial and temporal distributions of Secchi depths and chlorophyll a concentrations in the Suo Nada of the Seto Inland Sea, Japan, exposed to anthropogenic nutrient loading.

    PubMed

    Nishijima, Wataru; Umehara, Akira; Sekito, Satoshi; Okuda, Tetsuji; Nakai, Satoshi

    2016-11-15

    Thirty years of monitoring data were used to elucidate the spatial and temporal distributions of Secchi depths in the Suo Nada (Suo Sea) and to evaluate how chlorophyll a concentration and reductions of nutrient loading from the watershed affected those distributions. Secchi depths throughout the Suo Nada were positively correlated with water depths. The spatial and temporal variations of Secchi depths could be explained by variations of phytoplankton biomass in areas where the water depth exceeded 20m, but in areas shallower than 10m, other factors affecting light attenuation beside phytoplankton, which include suspended particulate matter and chromophoric dissolved organic matter, obscured relationships between phytoplankton biomass and Secchi depths. Phosphorus limited phytoplankton biomass in the Suo Nada. The main source of allochthonous phosphorus from the 1980s to the 1990s was the watershed. Because of significant reductions of nutrient loading from the watershed, the Pacific Ocean will most likely be the principal source of allochthonous phosphorus after around 2000, except in areas shallower than 10m. PMID:27395073

  15. Spatial and temporal distributions of Secchi depths and chlorophyll a concentrations in the Suo Nada of the Seto Inland Sea, Japan, exposed to anthropogenic nutrient loading.

    PubMed

    Nishijima, Wataru; Umehara, Akira; Sekito, Satoshi; Okuda, Tetsuji; Nakai, Satoshi

    2016-11-15

    Thirty years of monitoring data were used to elucidate the spatial and temporal distributions of Secchi depths in the Suo Nada (Suo Sea) and to evaluate how chlorophyll a concentration and reductions of nutrient loading from the watershed affected those distributions. Secchi depths throughout the Suo Nada were positively correlated with water depths. The spatial and temporal variations of Secchi depths could be explained by variations of phytoplankton biomass in areas where the water depth exceeded 20m, but in areas shallower than 10m, other factors affecting light attenuation beside phytoplankton, which include suspended particulate matter and chromophoric dissolved organic matter, obscured relationships between phytoplankton biomass and Secchi depths. Phosphorus limited phytoplankton biomass in the Suo Nada. The main source of allochthonous phosphorus from the 1980s to the 1990s was the watershed. Because of significant reductions of nutrient loading from the watershed, the Pacific Ocean will most likely be the principal source of allochthonous phosphorus after around 2000, except in areas shallower than 10m.

  16. METHOD OF DISSOLVING URANIUM METAL

    DOEpatents

    Slotin, L.A.

    1958-02-18

    This patent relates to an economicai means of dissolving metallic uranium. It has been found that the addition of a small amount of perchloric acid to the concentrated nitric acid in which the uranium is being dissolved greatly shortens the time necessary for dissolution of the metal. Thus the use of about 1 or 2 percent of perchioric acid based on the weight of the nitric acid used, reduces the time of dissolution of uranium by a factor of about 100.

  17. Identification of Reprocessed Depleted Uranium in Contaminated Sediments From Cs-137 Activity Measurements

    NASA Astrophysics Data System (ADS)

    Arnason, J. G.; Bopp, R. F.

    2006-05-01

    Measurements of U series isotopes and fission products can be used to distinguish the relative contributions of natural and anthropogenic sources in U-contaminated sites. Anthropogenic sources include enriched uranium, depleted uranium (DU) byproduct from ore enrichment, and DU byproduct from spent fuel reprocessing. From 1958 to 1984 the National Lead industries plant in Colonie, New York, USA, emitted more than four metric tons of uranium as microscopic uranium oxide aerosols within a 1 km radius of the plant. Previous studies of a 3-m-long sediment core from Patroon Reservoir, located 1 km downstream of the plant, indicate that between 1.8 and 1.0 m depth, U concentrations are more than 100 times natural background and consist of 25 to 95 percent depleted uranium based on alpha spectroscopy. We measured 18 samples by gamma spectroscopy to better constrain the chronology of the core. Cesium-137 shows two activity peaks, one at approximately 2.0 m and another, broader peak between 1.5 and 1.0 m depth. The lower peak corresponds to the global fallout maximum of the mid 1960's and indicates a 5.5-6 cm/yr sedimentation rate that is consistent with the excess Pb-210 profile. In contrast, the upper Cs-137 peak corresponds to the interval containing DU, and suggests that there is a DU component derived from spent nuclear fuel. This hypothesis is consistent with a published report of U-236 detected in DU particles collected in air filters 15 km away at the Knolls Atomic Power Lab during the time of plant operation. It can be further tested through high resolution isotopic measurements of U-236 in the sediments themselves. Depleted uranium derived from spent fuel and containing U-236 will have higher total activity than DU derived from U ore and, as a result, could represent a greater hazard in the environment.

  18. Microbial accumulation of uranium, radium, and cesium

    SciTech Connect

    Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

    1981-05-01

    Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested.

  19. Application of the angle measure technique as image texture analysis method for the identification of uranium ore concentrate samples: New perspective in nuclear forensics.

    PubMed

    Fongaro, Lorenzo; Ho, Doris Mer Lin; Kvaal, Knut; Mayer, Klaus; Rondinella, Vincenzo V

    2016-05-15

    The identification of interdicted nuclear or radioactive materials requires the application of dedicated techniques. In this work, a new approach for characterizing powder of uranium ore concentrates (UOCs) is presented. It is based on image texture analysis and multivariate data modelling. 26 different UOCs samples were evaluated applying the Angle Measure Technique (AMT) algorithm to extract textural features on samples images acquired at 250× and 1000× magnification by Scanning Electron Microscope (SEM). At both magnifications, this method proved effective to classify the different types of UOC powder based on the surface characteristics that depend on particle size, homogeneity, and graininess and are related to the composition and processes used in the production facilities. Using the outcome data from the application of the AMT algorithm, the total explained variance was higher than 90% with Principal Component Analysis (PCA), while partial least square discriminant analysis (PLS-DA) applied only on the 14 black colour UOCs powder samples, allowed their classification only on the basis of their surface texture features (sensitivity>0.6; specificity>0.6). This preliminary study shows that this method was able to distinguish samples with similar composition, but obtained from different facilities. The mean angle spectral data obtained by the image texture analysis using the AMT algorithm can be considered as a specific fingerprint or signature of UOCs and could be used for nuclear forensic investigation. PMID:26992543

  20. METHOD OF DISSOLVING METALLIC URANIUM

    DOEpatents

    Schulz, W.W.

    1959-07-28

    A process is presented for more rapidly dissolving metallic uranium which comprises contacting the uranium with a mixture of nitric and phosphoric acids. The preferred concentration is a mixture which is about 10 M in nitric acid and between 0.1 to 0.15 M in phosphoric acid.

  1. Cellular localization of uranium in the renal proximal tubules during acute renal uranium toxicity.

    PubMed

    Homma-Takeda, Shino; Kitahara, Keisuke; Suzuki, Kyoko; Blyth, Benjamin J; Suya, Noriyoshi; Konishi, Teruaki; Terada, Yasuko; Shimada, Yoshiya

    2015-12-01

    Renal toxicity is a hallmark of uranium exposure, with uranium accumulating specifically in the S3 segment of the proximal tubules causing tubular damage. As the distribution, concentration and dynamics of accumulated uranium at the cellular level is not well understood, here, we report on high-resolution quantitative in situ measurements by high-energy synchrotron radiation X-ray fluorescence analysis in renal sections from a rat model of uranium-induced acute renal toxicity. One day after subcutaneous administration of uranium acetate to male Wistar rats at a dose of 0.5 mg uranium kg(-1) body weight, uranium concentration in the S3 segment of the proximal tubules was 64.9 ± 18.2 µg g(-1) , sevenfold higher than the mean renal uranium concentration (9.7 ± 2.4 µg g(-1) ). Uranium distributed into the epithelium of the S3 segment of the proximal tubules and highly concentrated uranium (50-fold above mean renal concentration) in micro-regions was found near the nuclei. These uranium levels were maintained up to 8 days post-administration, despite more rapid reductions in mean renal concentration. Two weeks after uranium administration, damaged areas were filled with regenerating tubules and morphological signs of tissue recovery, but areas of high uranium concentration (100-fold above mean renal concentration) were still found in the epithelium of regenerating tubules. These data indicate that site-specific accumulation of uranium in micro-regions of the S3 segment of the proximal tubules and retention of uranium in concentrated areas during recovery are characteristics of uranium behavior in the kidney.

  2. Aluminosilicate Precipitation Impact on Uranium

    SciTech Connect

    WILMARTH, WILLIAM

    2006-03-10

    Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. This aspect was not thoroughly understood prior to this work and was necessary to avoid criticality issues when actual tank wastes were aggregated. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs concomitant with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted.

  3. Characterization of anthropogenic pollutants in Asian dust

    NASA Astrophysics Data System (ADS)

    Kim, W.; Doh, S.; Yu, Y.

    2008-12-01

    It has well known that the Asian dust storm (ADS) carried anthropogenic pollutants produced in the industrial areas in China to the adjacent East Asian nations including Korea, Japan and Taiwan. In order to characterize such anthropogenic pollutants forced by ADS, detailed electron microscopic observations were carried out on ADS samples collected from the 12 ADS events occurred for the past three years (2004-2006) in Seoul, Korea. In addition, their temporal accumulations were traced using magnetic proxy parameters. As a comparison, companion samples were also collected before- and after- ADS events. We found that anthropogenic signatures in the ADS samples were C, Cr, Pb, S and Zn. Most of these elements were tied with Fe. Therefore the magnetic proxy is highly applicable to trace the quantitative variations in anthropogenic pollutants in ADS. Slightly increasing magnetic concentration parameters reflect increasing amount of anthropogenic pollutants carried by the ADS for the past three years. Connecting with the air- mass trajectories of ADS, the highest magnetic concentration (highest pollution) was observed on the ADS samples from Central China which travelled nearby highly industrialized major cities where foreign multinational enterprises were concentrated.

  4. URANIUM COMPOSITIONS

    DOEpatents

    Allen, N.P.; Grogan, J.D.

    1959-05-12

    This patent relates to high purity uranium alloys characterized by improved stability to thermal cycling and low thermal neutron absorption. The high purity uranium alloy contains less than 0.1 per cent by weight in total amount of any ore or more of the elements such as aluminum, silicon, phosphorous, tin, lead, bismuth, niobium, and zinc.

  5. Isotopic studies of sources of uranium in sediments of the Ashtabula River, Ohio, U.S.A.

    SciTech Connect

    Ketterer, M.E.; Wetzel, W.C.; Layman, R.R.; Matisoff, G.; Bonniwell, E.C.

    2000-03-15

    Uranium contamination of anthropogenic origin has been identified in unconsolidated sediment of a 1.5 km portion of the Ashtabula River near its confluence with Lake Erie. Uranium concentrations as high as 188 {mu}g/g dry sediment are present. A small tributary of the Ashtabula River, Fields Brook, is the apparent point of origin of the uranium in the Ashtabula River sediments. {sup 137}Cs dating of a sediment core indicates that the U contamination occurred during the post-1964 time frame. The horizons of elevated U concentration also exhibit > 10x elevations in Zr, Nb, Hf, Ta, and W. {sup 238}U/{sup 235}U isotopic ratios indicate that the uranium is largely but not exclusively of natural composition. Distinct horizons of slightly {sup 235}U-depleted ({sup 238}U/{sup 235}U > 137.88) and slightly {sup 235}U-enriched ({sup 238}U/{sup 235}U < 137.88) uranium are also present. {sup 210}Pb activities and {sup 232}Th/{sup 230}Th isotopic measurements indicate that a significant portion of the uranium contains {sup 238}U daughters in approximate secular equilibrium. It is inferred that at least two distinct sources of anthropogenic U contamination exist: (a) discharges from the processing of enriched and depleted U metal by a DOE contractor facility and (B) U-bearing wastes from the production of TiO{sub 2} from limonite and associated minerals. These isotopic methodologies are potentially useful in settings where releases of nonnatural {sup 238}U/{sup 235}U composition materials and/or naturally occurring radioactive material (NORM) have taken place.

  6. Organic matter and sandstone-type uranium deposits: a primer

    USGS Publications Warehouse

    Leventhal, Joel S.

    1979-01-01

    Organic material is intimately associated with sandstone-type uranium deposits in the western United States.. This report gives details of the types of organic matter and their possible role in producing a uranium deposit. These steps include mobilization of uranium from igneous rocks, transportation from the surface, concentration by organic matter, reduction by organic matter, and preservation of the uranium deposit.

  7. Renal effects of uranium in drinking water.

    PubMed

    Kurttio, Päivi; Auvinen, Anssi; Salonen, Laina; Saha, Heikki; Pekkanen, Juha; Mäkeläinen, Ilona; Väisänen, Sari B; Penttilä, Ilkka M; Komulainen, Hannu

    2002-04-01

    Animal studies and small studies in humans have shown that uranium is nephrotoxic. However, more information about its renal effects in humans following chronic exposure through drinking water is required. We measured uranium concentrations in drinking water and urine in 325 persons who had used drilled wells for drinking water. We measured urine and serum concentrations of calcium, phosphate, glucose, albumin, creatinine, and beta-2-microglobulin to evaluate possible renal effects. The median uranium concentration in drinking water was 28 microg/L (interquartile range 6-135, max. 1,920 microg/L) and in urine 13 ng/mmol creatinine (2-75), resulting in the median daily uranium intake of 39 microg (7-224). Uranium concentration in urine was statistically significantly associated with increased fractional excretion of calcium and phosphate. Increase of uranium in urine by 1 microg/mmol creatinine increased fractional excretion of calcium by 1.5% [95% confidence interval (CI), 0.6-2.3], phosphate by 13% (1.4-25), and glucose excretion by 0.7 micromol/min (-0.4-1.8). Uranium concentrations in drinking water and daily intake of uranium were statistically significantly associated with calcium fractional excretion, but not with phosphate or glucose excretion. Uranium exposure was not associated with creatinine clearance or urinary albumin, which reflect glomerular function. In conclusion, uranium exposure is weakly associated with altered proximal tubulus function without a clear threshold, which suggests that even low uranium concentrations in drinking water can cause nephrotoxic effects. Despite chronic intake of water with high uranium concentration, we observed no effect on glomerular function. The clinical and public health relevance of the findings are not easily established, but our results suggest that the safe concentration of uranium in drinking water may be within the range of the proposed guideline values of 2-30 microg/L.

  8. Renal effects of uranium in drinking water.

    PubMed Central

    Kurttio, Päivi; Auvinen, Anssi; Salonen, Laina; Saha, Heikki; Pekkanen, Juha; Mäkeläinen, Ilona; Väisänen, Sari B; Penttilä, Ilkka M; Komulainen, Hannu

    2002-01-01

    Animal studies and small studies in humans have shown that uranium is nephrotoxic. However, more information about its renal effects in humans following chronic exposure through drinking water is required. We measured uranium concentrations in drinking water and urine in 325 persons who had used drilled wells for drinking water. We measured urine and serum concentrations of calcium, phosphate, glucose, albumin, creatinine, and beta-2-microglobulin to evaluate possible renal effects. The median uranium concentration in drinking water was 28 microg/L (interquartile range 6-135, max. 1,920 microg/L) and in urine 13 ng/mmol creatinine (2-75), resulting in the median daily uranium intake of 39 microg (7-224). Uranium concentration in urine was statistically significantly associated with increased fractional excretion of calcium and phosphate. Increase of uranium in urine by 1 microg/mmol creatinine increased fractional excretion of calcium by 1.5% [95% confidence interval (CI), 0.6-2.3], phosphate by 13% (1.4-25), and glucose excretion by 0.7 micromol/min (-0.4-1.8). Uranium concentrations in drinking water and daily intake of uranium were statistically significantly associated with calcium fractional excretion, but not with phosphate or glucose excretion. Uranium exposure was not associated with creatinine clearance or urinary albumin, which reflect glomerular function. In conclusion, uranium exposure is weakly associated with altered proximal tubulus function without a clear threshold, which suggests that even low uranium concentrations in drinking water can cause nephrotoxic effects. Despite chronic intake of water with high uranium concentration, we observed no effect on glomerular function. The clinical and public health relevance of the findings are not easily established, but our results suggest that the safe concentration of uranium in drinking water may be within the range of the proposed guideline values of 2-30 microg/L. PMID:11940450

  9. URANIUM SOLVENT EXTRACTION PROCESS

    DOEpatents

    Harrington, C.D.

    1959-09-01

    A method is given for extracting uranium values from ores of high phosphate content consisting of dissolving them in aqueous nitric acid, adjusting the concentration of the aqueous solution to about 2 M with respect to nitric acid, and then contacting it with diethyl ether which has previously been made 1 M with respect to nitric acid.

  10. SURFACE TREATMENT OF METALLIC URANIUM

    DOEpatents

    Gray, A.G.; Schweikher, E.W.

    1958-05-27

    The treatment of metallic uranium to provide a surface to which adherent electroplates can be applied is described. Metallic uranium is subjected to an etchant treatment in aqueous concentrated hydrochloric acid, and the etched metal is then treated to dissolve the resulting black oxide and/or chloride film without destroying the etched metal surface. The oxide or chloride removal is effected by means of moderately concentrated nitric acid in 3 to 20 seconds.

  11. TREATMENT OF URANIUM SURFACES

    DOEpatents

    Slunder, C.J.

    1959-02-01

    An improved process is presented for prcparation of uranium surfaces prior to electroplating. The surfacc of the uranium to be electroplated is anodized in a bath comprising a solution of approximately 20 to 602 by weight of phosphoric acid which contains about 20 cc per liter of concentrated hydrochloric acid. Anodization is carried out for approximately 20 minutes at a current density of about 0.5 amperes per square inch at a temperature of about 35 to 45 C. The oxidic film produced by anodization is removed by dipping in strong nitric acid, followed by rinsing with water just prior to electroplating.

  12. Anthropogenic Aerosols and Tropical Precipitation

    NASA Astrophysics Data System (ADS)

    Wang, C.; Kim, D.; Ekman, A. M. L.; Barth, M. C.; Rasch, P. J.

    2009-04-01

    Anthropogenic aerosols can affect the radiative balance of the Earth-atmosphere system and precipitation by acting as cloud condensation nuclei (CCN) or ice nuclei (IN) and thus modifying the optical and microphysical properties as well as lifetimes of clouds. Recent studies have also suggested that the direct radiative effect of anthropogenic aerosols, particularly absorbing aerosols, can perturb the large-scale circulation and cause a significant change in both quantity and distribution of critical tropical precipitation systems ranging from Pacific and Indian to Atlantic Oceans. This effect of aerosols on precipitation often appears in places away from aerosol-concentrated regions and current results suggest that the precipitation changes caused by it could be much more substantial than that by the microphysics-based aerosol effect. To understand the detailed mechanisms and strengths of such a "remote impact" and the climate response/feedback to anthropogenic aerosols in general, an interactive aerosol-climate model has been developed based on the Community Climate System Model (CCSM) of NCAR. Its aerosol module describes size, chemical composition, and mixing states of various sulfate and carbonaceous aerosols. Several model processes are derived based on 3D cloud-resolving model simulations. We have conducted a set of long integrations using the model driven by radiative effects of different combinations of various carbonaceous and sulfate aerosols and their mixtures. The responses of tropical precipitation systems to the forcing of these aerosols are analyzed using both model and observational data. Detailed analyses on the aerosol-precipitation causal relations of two systems: i.e., the Indian summer monsoon and Pacific ITCZ will be specifically presented.

  13. Geomorphology of anthropogenic landscapes

    NASA Astrophysics Data System (ADS)

    Sofia, Giulia; Tarolli, Paolo

    2015-04-01

    The construction of urban areas and the development of road networks leave a significant signature on the Earth surface, providing a geomorphological evidence to support the idea that humans are nowadays a geomorphic agent having deep effects on the morphological organization of the landscape. The reconstruction or identification of anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the Anthropocene. Following this research line, the present study tests the effectiveness of a recently published topographic index, the Slope Local Length of Autocorrelation (SLLAC, Sofia et al. 2014) to portrait anthropogenic geomorphology, focusing in particular on road network density, and urban complexity (UCI). At first, the research considers the increasing of anthropic structures and the resulting changes in the SLLAC and in two derived parameters (mean SLLAC per km2 and SLLAC roughness, or Surface Peak Curvature -Spc). As a second step, considering the SLLAC derived indices, the anthropogenic geomorphology is automatically depicted using a k-means clustering algorithm. In general, the increasing of road network density or of the UCI is positively correlated to the mean SLLAC per km2, while the Spc is negatively correlated to the increasing of the anthropic structures. Areas presenting different road network organization are effectively captured considering multiple combinations of the defined parameters. Landscapes with small scattered towns, and a network with long roads in a dendritic shape (with hierarchical branching) are characterized simultaneously by high mean SLLAC and low Spc. Large and complex urban areas served by rectilinear networks with numerous short straight lines and right angles, have either a maximized mean SLLAC or a minimized Spc or both. In all cases, the anthropogenic landscape identified by the procedure is comparable to the ones identified manually from orthophoto, with the

  14. Uranium Metal Analysis via Selective Dissolution

    SciTech Connect

    Delegard, Calvin H.; Sinkov, Sergey I.; Schmidt, Andrew J.; Chenault, Jeffrey W.

    2008-09-10

    Uranium metal, which is present in sludge held in the Hanford Site K West Basin, can create hazardous hydrogen atmospheres during sludge handling, immobilization, or subsequent transport and storage operations by its oxidation/corrosion in water. A thorough knowledge of the uranium metal concentration in sludge therefore is essential to successful sludge management and waste process design. The goal of this work was to establish a rapid routine analytical method to determine uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of up to 1000-fold higher total uranium concentrations (i.e., up to 30 wt% and more uranium) for samples to be taken during the upcoming sludge characterization campaign and in future analyses for sludge handling and processing. This report describes the experiments and results obtained in developing the selective dissolution technique to determine uranium metal concentration in K Basin sludge.

  15. JACKETING URANIUM

    DOEpatents

    Saller, H.A.; Keeler, J.R.

    1959-07-14

    The bonding to uranium of sheathing of iron or cobalt, or nickel, or alloys thereof is described. The bonding is accomplished by electro-depositing both surfaces to be joined with a coating of silver and amalgamating or alloying the silver layer with mercury or indium. Then the silver alloy is homogenized by exerting pressure on an assembly of the uranium core and the metal jacket, reducing the area of assembly and heating the assembly to homogenize by diffusion.

  16. Uranium uptake by hydroponically cultivated crop plants.

    PubMed

    Soudek, Petr; Petrová, Sárka; Benešová, Dagmar; Dvořáková, Marcela; Vaněk, Tomáš

    2011-06-01

    Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC(50) value about 0.1mM. Cucumis sativa represented the most resistant plant to uranium (EC(50)=0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1mM. Twenty different plant species were tested in hydroponic solution supplemented by 0.1mM or 0.5mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.

  17. Isotopic ratio method for determining uranium contamination

    SciTech Connect

    Miles, R.E.; Sieben, A.K.

    1994-02-03

    The presence of high concentrations of uranium in the subsurface can be attributed either to contamination from uranium processing activities or to naturally occurring uranium. A mathematical method has been employed to evaluate the isotope ratios from subsurface soils at the Rocky Flats Nuclear Weapons Plant (RFP) and demonstrates conclusively that the soil contains uranium from a natural source and has not been contaminated with enriched uranium resulting from RFP releases. This paper describes the method used in this determination which has widespread application in site characterizations and can be adapted to other radioisotopes used in manufacturing industries. The determination of radioisotope source can lead to a reduction of the remediation effort.

  18. Element concentrations in surface soils of the Coconino Plateau, Grand Canyon region, Coconino County, Arizona

    USGS Publications Warehouse

    Van Gosen, Bradley S.

    2016-09-15

    This report provides the geochemical analyses of a large set of background soils collected from the surface of the Coconino Plateau in northern Arizona. More than 700 soil samples were collected at 46 widespread areas, sampled from sites that appear unaffected by mineralization and (or) anthropogenic contamination. The soils were analyzed for 47 elements, thereby providing data on metal concentrations in soils representative of the plateau. These background concentrations can be used, for instance, for comparison to metal concentrations found in soils potentially affected by natural and anthropogenic influences on the Coconino Plateau in the Grand Canyon region of Arizona.The soil sampling survey revealed low concentrations for the metals most commonly of environmental concern, such as arsenic, cobalt, chromium, copper, mercury, manganese, molybdenum, lead, uranium, vanadium, and zinc. For example, the median concentrations of the metals in soils of the Coconino Plateau were found to be comparable to the mean values previously reported for soils of the western United States.

  19. Uranium Reduction by Clostridia

    SciTech Connect

    Francis, A.J.; Dodge, Cleveland J.; Gillow, Jeffrey B.

    2006-04-05

    The FRC groundwater and sediment contain significant concentrations of U and Tc and are dominated by low pH, and high nitrate and Al concentrations where dissimilatory metal reducing bacterial activity may be limited. The presence of Clostridia in Area 3 at the FRC site has been confirmed and their ability to reduce uranium under site conditions will be determined. Although the phenomenon of uranium reduction by Clostridia has been firmly established, the molecular mechanisms underlying such a reaction are not very clear. The authors are exploring the hypothesis that U(VI) reduction occurs through hydrogenases and other enzymes (Matin and Francis). Fundamental knowledge of metal reduction using Clostridia will allow us to exploit naturally occurring processes to attenuate radionuclide and metal contaminants in situ in the subsurface. The outline for this report are as follows: (1) Growth of Clostridium sp. under normal culture conditions; (2) Fate of metals and radionuclides in the presence of Clostridia; (3) Bioreduction of uranium associated with nitrate, citrate, and lepidocrocite; and (4) Utilization of Clostridium sp. for immobilization of uranium at the FRC Area 3 site.

  20. Solubility measurement of uranium in uranium-contaminated soils

    SciTech Connect

    Lee, S.Y.; Elless, M.; Hoffman, F.

    1993-08-01

    A short-term equilibration study involving two uranium-contaminated soils at the Fernald site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. The soluble levels of total uranium, calcium, magnesium, and carbonate increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium or continued linearity throughout the study. Aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles. Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. The development of a site-specific remediation technology is urgently needed for the FEMP site.

  1. SEPARATION OF URANIUM FROM THORIUM

    DOEpatents

    Hellman, N.N.

    1959-07-01

    A process is presented for separating uranium from thorium wherein the ratio of thorium to uranium is between 100 to 10,000. According to the invention the thoriumuranium mixture is dissolved in nitric acid, and the solution is prepared so as to obtain the desired concentration within a critical range of from 4 to 8 N with regard to the total nitrate due to thorium nitrate, with or without nitric acid or any nitrate salting out agent. The solution is then contacted with an ether, such as diethyl ether, whereby uranium is extracted into ihe organic phase while thorium remains in the aqueous phase.

  2. Laser induced phosphorescence uranium analysis

    DOEpatents

    Bushaw, B.A.

    1983-06-10

    A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

  3. Colorimetric detection of uranium in water

    DOEpatents

    DeVol, Timothy A.; Hixon, Amy E.; DiPrete, David P.

    2012-03-13

    Disclosed are methods, materials and systems that can be used to determine qualitatively or quantitatively the level of uranium contamination in water samples. Beneficially, disclosed systems are relatively simple and cost-effective. For example, disclosed systems can be utilized by consumers having little or no training in chemical analysis techniques. Methods generally include a concentration step and a complexation step. Uranium concentration can be carried out according to an extraction chromatographic process and complexation can chemically bind uranium with a detectable substance such that the formed substance is visually detectable. Methods can detect uranium contamination down to levels even below the MCL as established by the EPA.

  4. Uranium bombs

    NASA Astrophysics Data System (ADS)

    DeGroot, Gerard

    2009-11-01

    Enrico Fermi was a brilliant physicist, but he did occasionally get things wrong. In 1934 he famously bombarded a sample of uranium with neutrons. The result was astounding: the experiment had, Fermi concluded, produced element 93, later called neptunium. The German physicist Ida Noddack, however, came to an even more spectacular conclusion, namely that Fermi had split the uranium nucleus to produce lighter elements. Noddack's friend Otto Hahn judged that idea preposterous and advised her to keep quiet, since ridicule could ruin a female physicist. She ignored that advice, and was, indeed, scorned.

  5. ELUTION OF URANIUM FROM RESIN

    DOEpatents

    McLEan, D.C.

    1959-03-10

    A method is described for eluting uranium from anion exchange resins so as to decrease vanadium and iron contamination and permit recycle of the major portion of the eluats after recovery of the uranium. Diminution of vanadium and iron contamination of the major portion of the uranium is accomplished by treating the anion exchange resin, which is saturated with uranium complex by adsorption from a sulfuric acid leach liquor from an ore bearing uranium, vanadium and iron, with one column volume of eluant prepared by passing chlorine into ammonium hydroxide until the chloride content is about 1 N and the pH is about 1. The resin is then eluted with 8 to 9 column volumes of 0.9 N ammonium chloride--0.1 N hydrochloric acid solution. The eluants are collected separately and treated with ammonia to precipitate ammonium diuranate which is filtered therefrom. The uranium salt from the first eluant is contaminated with the major portion of ths vanadium and iron and is reworked, while the uranium recovered from the second eluant is relatively free of the undesirable vanadium and irons. The filtrate from the first eluant portion is discarded. The filtrate from the second eluant portion may be recycled after adding hydrochloric acid to increase the chloride ion concentration and adjust the pH to about 1.

  6. Machining of uranium and uranium alloys

    SciTech Connect

    Morris, T.O.

    1981-12-14

    Uranium and uranium alloys can be readily machined by conventional methods in the standard machine shop when proper safety and operating techniques are used. Material properties that affect machining processes and recommended machining parameters are discussed. Safety procedures and precautions necessary in machining uranium and uranium alloys are also covered. 30 figures.

  7. URANIUM ALLOYS

    DOEpatents

    Seybolt, A.U.

    1958-04-15

    Uranium alloys containing from 0.1 to 10% by weight, but preferably at least 5%, of either zirconium, niobium, or molybdenum exhibit highly desirable nuclear and structural properties which may be improved by heating the alloy to about 900 d C for an extended period of time and then rapidly quenching it.

  8. Uranium, natural

    Integrated Risk Information System (IRIS)

    Uranium , natural ; CASRN 7440 - 61 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  9. Determination of uranium in natural waters

    USGS Publications Warehouse

    Thatcher, L.L.; Barker, F.B.

    1957-01-01

    The fluorophotometric determination of uranium was studied to develop a procedure applicable to the routine analysis of waters. Three grams of the high carbonate flux are used in a dilution procedure with spiking. Because of the comparatively high reflectivity of this large disk and the low uranium concentration, a correction for nonquenched light is required. A formula is developed to compensate for the effect, an electrical fusion device is described, and the problem of fixing uranium in waters is discussed.

  10. Response of California temperature to regional anthropogenic aerosol changes

    SciTech Connect

    Kirchstetter, Thomas; Novakov, T.; Kirchstetter, T.W.; Menon, S.; Aguiar, J.

    2008-05-12

    In this paper, we compare constructed records of concentrations of black carbon (BC)--an indicator of anthropogenic aerosols--with observed surface temperature trends in California. Annual average BC concentrations in major air basins in California significantly decreased after about 1990, coincident with an observed statewide surface temperature increase. Seasonal aerosol concentration trends are consistent with observed seasonal temperature trends. These data suggest that the reduction in anthropogenic aerosol concentrations contributed to the observed surface temperature increase. Conversely, high aerosol concentrations may lower surface temperature and partially offset the temperature increase of greenhouse gases.

  11. Beneficial Uses of Depleted Uranium

    SciTech Connect

    Brown, C.; Croff, A.G.; Haire, M. J.

    1997-08-01

    Naturally occurring uranium contains 0.71 wt% {sup 235}U. In order for the uranium to be useful in most fission reactors, it must be enriched the concentration of the fissile isotope {sup 235}U must be increased. Depleted uranium (DU) is a co-product of the processing of natural uranium to produce enriched uranium, and DU has a {sup 235}U concentration of less than 0.71 wt%. In the United States, essentially all of the DU inventory is in the chemical form of uranium hexafluoride (UF{sub 6}) and is stored in large cylinders above ground. If this co-product material were to be declared surplus, converted to a stable oxide form, and disposed, the costs are estimated to be several billion dollars. Only small amounts of DU have at this time been beneficially reused. The U.S. Department of Energy (DOE) has begun the Beneficial Uses of DU Project to identify large-scale uses of DU and encourage its reuse for the primary purpose of potentially reducing the cost and expediting the disposition of the DU inventory. This paper discusses the inventory of DU and its rate of increase; DU disposition options; beneficial use options; a preliminary cost analysis; and major technical, institutional, and regulatory issues to be resolved.

  12. Uranium from seawater

    SciTech Connect

    Gregg, D.; Folkendt, M.

    1982-09-21

    A novel process for recovering uranium from seawater is proposed and some of the critical technical parameters are evaluated. The process, in summary, consists of two different options for contacting adsorbant pellets with seawater without pumping the seawater. It is expected that this will reduce the mass handling requirements, compared to pumped seawater systems, by a factor of approximately 10/sup 5/, which should also result in a large reduction in initial capital investment. Activated carbon, possibly in combination with a small amount of dissolved titanium hydroxide, is expected to be the preferred adsorbant material instead of the commonly assumed titanium hydroxide alone. The activated carbon, after exposure to seawater, can be stripped of uranium with an appropriate eluant (probably an acid) or can be burned for its heating value (possible in a power plant) leaving the uranium further enriched in its ash. The uranium, representing about 1% of the ash, is then a rich ore and would be recovered in a conventional manner. Experimental results have indicated that activated carbon, acting alone, is not adequately effective in adsorbing the uranium from seawater. We measured partition coefficients (concentration ratios) of approximately 10/sup 3/ in seawater instead of the reported values of 10/sup 5/. However, preliminary tests carried out in fresh water show considerable promise for an extraction system that uses a combination of dissolved titanium hydroxide (in minute amounts) which forms an insoluble compound with the uranyl ion, and the insoluble compound then being sorbed out on activated carbon. Such a system showed partition coefficients in excess of 10/sup 5/ in fresh water. However, the system was not tested in seawater.

  13. Anthropogenic nutrients and harmful algae in coastal waters.

    PubMed

    Davidson, Keith; Gowen, Richard J; Harrison, Paul J; Fleming, Lora E; Hoagland, Porter; Moschonas, Grigorios

    2014-12-15

    Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking.

  14. Anthropogenic nutrients and harmful algae in coastal waters.

    PubMed

    Davidson, Keith; Gowen, Richard J; Harrison, Paul J; Fleming, Lora E; Hoagland, Porter; Moschonas, Grigorios

    2014-12-15

    Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking. PMID:25173729

  15. Transient proteinuria and aminoaciduria in rodents following uranium intoxication

    SciTech Connect

    Bentley, K.W.; Stockwell, D.R.; Britt, K.A.; Kerr, C.B.

    1985-03-01

    Alternative human bioassay procedures for uranium are being investigated. Aminoaciduria in uranium hexafluoride and uranium mill employees has been examined. Although not conclusive, the results suggest that chronic human urinary uranium concentrations of 30-50 ..mu..g L/sup -1/ produce marked changes in the amino acid excretion profile although no consistent patterns emerged. As part of a program to examine alternative bioassay techniques for occupationally exposed uranium workers and to assist in interpretation of amino acid obtained from human incident exposures, the authors have examined the occurrence of transient aminoaciduria following uranium intoxication in female rats.

  16. Possible Influence of Anthropogenic Aerosols on Cirrus Clouds and Anthropogenic Forcing

    SciTech Connect

    Penner, Joyce E.; Chen, Yang; Wang, Minghuai; Liu, Xiaohong

    2009-02-03

    Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth’s area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We find that fossil fuel and biomass burning soot aerosols exert a radiative forcing of -0.68 to 0.01 Wm-2 while anthropogenic sulfate aerosols exert a forcing of -0.01 to 0.18 Wm-2. Our calculations show that the sign of the forcing by aircraft soot depends on the model configuration and can be both positive or negative, ranging from -0.16 to 0.02 Wm-2. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

  17. Depleted Uranium in Repositories

    SciTech Connect

    Haire, M.J.; Croff, A.G.

    1997-12-31

    For uranium to be useful in most fission nuclear reactors, it must be enriched (i.e. the concentration of the fissile isotope 235U must be increased). Therefore, depleted uranium (DU)-uranium which has less than naturally occurring concentrations of 235U-is a co-product of the enrichment process. Four to six tons of DU exist for every ton of fresh light water reactor fuel. There were 407,006 MgU 407,000 metric tons (t) of DU stored on U.S. Department of Energy (DOE) sites as of July 1993. If this DU were to be declared surplus, converted to a stable oxide form, and emplaced in a near surface disposal facility, the costs are estimated to be several billion dollars. However, the U.S. Nuclear Regulatory Commission has stated that near surface disposal of large quantities of DU tails is not appropriate. Thus, there is the possibility that disposition via disposal will be in a deep geological repository. One alternative that may significantly reduce the cost of DU disposition is to use it beneficially. In fact, DOE has begun the Beneficial Uses of DU Project to identify large scale uses of DU and to encourage its reuse. Several beneficial uses, many of which involve applications in the repository per se or in managing the wastes to go into the repository, are discussed in this report.

  18. Assessment of potential migration of radionuclides and trace elements from the White Mesa uranium mill to the Ute Mountain Ute Reservation and surrounding areas, southeastern Utah

    USGS Publications Warehouse

    Naftz, David L.; Ranalli, Anthony J.; Rowland, Ryan C.; Marston, Thomas M.

    2011-01-01

    In 2007, the Ute Mountain Ute Tribe requested that the U.S. Environmental Protection Agency and U.S. Geological Survey conduct an independent evaluation of potential offsite migration of radionuclides and selected trace elements associated with the ore storage and milling process at an active uranium mill site near White Mesa, Utah. Specific objectives of this study were (1) to determine recharge sources and residence times of groundwater surrounding the mill site, (2) to determine the current concentrations of uranium and associated trace elements in groundwater surrounding the mill site, (3) to differentiate natural and anthropogenic contaminant sources to groundwater resources surrounding the mill site, (4) to assess the solubility and potential for offsite transport of uranium-bearing minerals in groundwater surrounding the mill site, and (5) to use stream sediment and plant material samples from areas surrounding the mill site to identify potential areas of offsite contamination and likely contaminant sources. The results of age-dating methods and an evaluation of groundwater recharge temperatures using dissolved-gas samples indicate that groundwater sampled in wells in the surficial aquifer in the vicinity of the mill is recharged locally by precipitation. Tritium/helium age dating methods found a "modern day" apparent age in water samples collected from springs in the study area surrounding the mill. This apparent age indicates localized recharge sources that potentially include artificial recharge of seepage from constructed wildlife refuge ponds near the mill. The stable oxygen isotope-ratio, delta oxygen-18, or δ(18O/16O), known as δ18O, and hydrogen isotope-ratio, delta deuterium, or δ(2H/1H), known as δD, data indicate that water discharging from Entrance Spring is isotopically enriched by evaporation and has a similar isotopic fingerprint as water from Recapture Reservoir, which is used as facilities water on the mill site. Water from Recapture

  19. Anthropogenic Sulfate, Clouds, and Climate Forcing

    NASA Technical Reports Server (NTRS)

    Ghan, Steven J.

    1997-01-01

    This research work is a joint effort between research groups at the Battelle Pacific Northwest Laboratory, Virginia Tech University, Georgia Institute of Technology, Brookhaven National Laboratory, and Texas A&M University. It has been jointly sponsored by the National Aeronautics and Space Administration, the U.S. Department of Energy, and the U.S. Environmental Protection Agency. In this research, a detailed tropospheric aerosol-chemistry model that predicts oxidant concentrations as well as concentrations of sulfur dioxide and sulfate aerosols has been coupled to a general circulation model that distinguishes between cloud water mass and cloud droplet number. The coupled model system has been first validated and then used to estimate the radiative impact of anthropogenic sulfur emissions. Both the direct radiative impact of the aerosols and their indirect impact through their influence on cloud droplet number are represented by distinguishing between sulfuric acid vapor and fresh and aged sulfate aerosols, and by parameterizing cloud droplet nucleation in terms of vertical velocity and the number concentration of aged sulfur aerosols. Natural sulfate aerosols, dust, and carbonaceous and nitrate aerosols and their influence on the radiative impact of anthropogenic sulfate aerosols, through competition as cloud condensation nuclei, will also be simulated. Parallel simulations with and without anthropogenic sulfur emissions are performed for a global domain. The objectives of the research are: To couple a state-of-the-art tropospheric aerosol-chemistry model with a global climate model. To use field and satellite measurements to evaluate the treatment of tropospheric chemistry and aerosol physics in the coupled model. To use the coupled model to simulate the radiative (and ultimately climatic) impacts of anthropogenic sulfur emissions.

  20. Increased Concentrations of Short-Lived Decay-Series Radionuclides in Groundwaters Underneath the Nopal I Uranium Deposit at Pena Blanca, Mexico

    NASA Astrophysics Data System (ADS)

    Luo, S.; Ku, T.; Todd, V.; Murrell, M. T.; Dinsmoor, J. C.

    2007-05-01

    The Nopal I uranium ore deposit at Pena Blanca, Mexico, located at > 200 meters above the groundwater table, provides an ideal natural analog for quantifying the effectiveness of geological barrier for isolation of radioactive waste nuclides from reaching the human environments through ground water transport. To fulfill such natural analog studies, three wells (PB1, PB2, and PB3 respectively) were drilled at the site from the land surface down to the saturated groundwater zone and ground waters were collected from each of these wells through large- volume sampling/in-situ Mn-filter filtration for analyses of short-lived uranium/thorium-series radionuclides. Our measurements from PB1 show that the groundwater standing in the hole has much lower 222Rn activity than the freshly pumped groundwater. From this change in 222Rn activity, we estimate the residence time of groundwater in PB1 to be about 20 days. Our measurements also show that the activities of short-lived radioisotopes of Th (234Th), Ra (228Ra, 224Ra, 223Ra), Rn (222Rn), Pb (210Pb), and Po (210Po) in PB1, PB2, and PB3 are all significantly higher than those from the other wells near the Nopal I site. These high activities provide evidence for the enrichment of long-lived U and Ra isotopes in the groundwater as well as in the associated adsorbed phases on the fractured aquifer rocks underneath the ore deposit. Such enrichment suggests a rapid dissolution of U and Ra isotopes from the uranium ore deposit in the vadose zone and the subsequent migration to the groundwater underneath. A reactive transport model can be established to characterize the in-situ transport of radionuclides at the site. The observed change of 222Rn activity at PB1 also suggests that the measured high radioactivityies in ground waters from the site isare not an artifact of drilling operations. However, further studies are needed to assess if or to what extent the radionuclide migration is affected by the previous mining activities at

  1. Coastal-ocean uptake of anthropogenic carbon

    NASA Astrophysics Data System (ADS)

    Bourgeois, Timothée; Orr, James C.; Resplandy, Laure; Terhaar, Jens; Ethé, Christian; Gehlen, Marion; Bopp, Laurent

    2016-07-01

    Anthropogenic changes in atmosphere-ocean and atmosphere-land CO2 fluxes have been quantified extensively, but few studies have addressed the connection between land and ocean. In this transition zone, the coastal ocean, spatial and temporal data coverage is inadequate to assess its global budget. Thus we use a global ocean biogeochemical model to assess the coastal ocean's global inventory of anthropogenic CO2 and its spatial variability. We used an intermediate resolution, eddying version of the NEMO-PISCES model (ORCA05), varying from 20 to 50 km horizontally, i.e. coarse enough to allow multiple century-scale simulations but finer than coarse-resolution models (˜ 200 km) to better resolve coastal bathymetry and complex coastal currents. Here we define the coastal zone as the continental shelf area, excluding the proximal zone. Evaluation of the simulated air-sea fluxes of total CO2 for 45 coastal regions gave a correlation coefficient R of 0.8 when compared to observation-based estimates. Simulated global uptake of anthropogenic carbon results averaged 2.3 Pg C yr-1 during the years 1993-2012, consistent with previous estimates. Yet only 0.1 Pg C yr-1 of that is absorbed by the global coastal ocean. That represents 4.5 % of the anthropogenic carbon uptake of the global ocean, less than the 7.5 % proportion of coastal-to-global-ocean surface areas. Coastal uptake is weakened due to a bottleneck in offshore transport, which is inadequate to reduce the mean anthropogenic carbon concentration of coastal waters to the mean level found in the open-ocean mixed layer.

  2. Evidence of uranium and associated trace element mobilization and retention processes at Oklo (Gabon), a naturally radioactive site.

    PubMed

    Casas, Ignasi; de Pablo, Joan; Pérez, Isabel; Giménez, Javier; Duro, Lara; Bruno, Jordi

    2004-06-15

    The processes that affect the mobility of uranium and other radionuclides in the environment have been largely studied at both the laboratory and the field scales. The natural reactors found at the Oklo uranium mine in Gabon constitute a unique investigation setting as spontaneous fission reactions occurred two billion years ago. Oklo uraninites contain a large amount of other radionuclides as a result of the fission process. We have investigated the dissolution behavior of four uraninite samples from Oklo as a function of temperature (25 and 60 degrees C) and bicarbonate concentration (2.7-30 mmol/L). We have also investigated the dissolution behavior of minor components of the uraninites (i.e., Nd, Cs, Mo, Yb, and Sb) in relation to the dissolution of uranium. The results of the reported work are in good agreement with the kinetic rate laws derived from other uranium(IV) dioxide studies. Some of the minor components are found to be congruently released from the uraninite phase, while it is postulated that dissolution from segregated phases might affect the final concentrations of some of the rare earth elements, i.e., Nd and Yb. In addition, we have performed dissolution studies at 60 degrees C with two uraninites representative of different geochemical environments at Oklo, to study the uranium dissolution rates as a function of the temperature. This has allowed derivation of apparent activation energies for the bicarbonate-promoted oxidative dissolution of the Oklo uraninites. The dissolution behavior of the minor components of the uraninites at 60 degrees C was found to closely follow the behavior observed at 25 degrees C. This indicates that similar codissolution mechanisms operate in the temperature range studied. The implications for the mobility of uranium and other radionuclides in natural and anthropogenic environments are discussed.

  3. Simple colorimetric method determines uranium in tissue

    NASA Technical Reports Server (NTRS)

    Doran, D.; Frigerio, N. A.

    1967-01-01

    Simple colorimetric micromethod determines concentrations of uranium in tissue. The method involves dry ashing organic extraction, and colorimetric determination of uranyl ferrocyanide. This uranium determination technique could be used in agricultural research, tracer studies, testing of food products, or medical research.

  4. Assessment of occupational exposure to uranium by indirect methods needs information on natural background variations.

    PubMed

    Muikku, M; Heikkinen, T; Puhakainen, M; Rahola, T; Salonen, L

    2007-01-01

    Urine monitoring is the preferred method to determine exposure to soluble compounds of uranium in workplaces. The interpretation of uranium contents in workers bioassay samples requires knowledge on uranium excretion and its dependence on intake by diet. Exceptionally high concentrations of natural uranium in private drinking water sources have been measured in the granite areas of Southern Finland. Consequently, high concentrations of natural uranium have been observed in the urine and hair samples of people using water from their own drilled wells. Natural uranium content in urine and hair samples of family members, who use uranium-rich household water, have been analyzed by using ICP-MS. The uranium concentrations both in urine and hair samples of the study subjects were significantly higher than the world-wide average values. In addition, gammaspectrometric methods have been tested for determining uranium in hair samples. This method can be used only for samples with highly elevated uranium concentrations.

  5. Radon as an Anthropogenic Indoor Air Pollutant

    NASA Astrophysics Data System (ADS)

    Gillmore, Gavin; Crockett, Robin

    2016-04-01

    Radon is generally regarded as a naturally occurring radiological hazard but we report here measurements of significant, hazardous radon concentrations that arise from man-made sources, including granite ornaments/artefacts, uranium glass and glazed objects as well radium dial watches. This presentation concerns an examination and assessment of health risks from radium and uranium found in historical artefacts, many of which were once viewed as everyday items, and the radon that emanates from them. Such objects were very popular in industrialised countries such as the USA, UK and European countries) particularly between and including the two World Wars but are still readily available. A watch collection examined gave rise to a hazardous radon concentration of 13.24 kBq•m-3 approximately 67 times the Domestic Action Level of 200 Bq•m-3.The results for an aircraft altimeter are comparable to those of the watches, indicating radon activity equivalent to several watches, and also indicate an equilibrium concentration in the 16.3 m3 room ca. 33 times the UK domestic Action Level. Results from a granite block indicate a radon emanation of 19.7 Bq•kg-1, but the indicated equilibrium concentration in the 16.3 m3 room is only ca. 1.7% of the UK domestic Action Level. Uranium-glazed crockery and green uranium glass were scoped for radon activity. The former yielded a radon concentration of ca. 44 Bq•m-3 in a small (7 L) sealed container. The latter yielded a lower radon concentration in a larger (125 L) sealed container of ca. 6 Bq•m-3. This is barely above the background radon concentration in the laboratory, which was typically ca. 1-2 Bq•m-3. Individual items then are capable of giving rise to radon concentrations in excess of the UK Domestic Action Level in rooms in houses, particularly if poorly ventilated. We highlight the gap in the remediation protocols, which are focused on preventing radon entering buildings from outside, with regard to internally

  6. Derived enriched uranium market

    SciTech Connect

    Rutkowski, E.

    1996-12-01

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market.

  7. PROCESS FOR RECOVERING URANIUM FROM AQUEOUS PHOSPHORIC ACID LIQUORS

    DOEpatents

    Schmitt, J.M.

    1962-09-01

    A liquid-liquid extraction method is given for recovering uranium values from aqueous solutions. An acidic aqueous solution containing uranium values is contacted with an organic phase comprising an organic diluent and the reaction product of phosphorous pentoxide and a substantially pure dialkylphosphoric acid. The uranium values are transferred to the organic phase even from aqueous solutions containing a high concentration of strong uranium complexing agents such as phosphate ions. (AEC)

  8. Assessment of potential migration of radionuclides and trace elements from the White Mesa uranium mill to the Ute Mountain Ute Reservation and surrounding areas, southeastern Utah

    USGS Publications Warehouse

    Naftz, David L.; Ranalli, Anthony J.; Rowland, Ryan C.; Marston, Thomas M.

    2011-01-01

    In 2007, the Ute Mountain Ute Tribe requested that the U.S. Environmental Protection Agency and U.S. Geological Survey conduct an independent evaluation of potential offsite migration of radionuclides and selected trace elements associated with the ore storage and milling process at an active uranium mill site near White Mesa, Utah. Specific objectives of this study were (1) to determine recharge sources and residence times of groundwater surrounding the mill site, (2) to determine the current concentrations of uranium and associated trace elements in groundwater surrounding the mill site, (3) to differentiate natural and anthropogenic contaminant sources to groundwater resources surrounding the mill site, (4) to assess the solubility and potential for offsite transport of uranium-bearing minerals in groundwater surrounding the mill site, and (5) to use stream sediment and plant material samples from areas surrounding the mill site to identify potential areas of offsite contamination and likely contaminant sources. The results of age-dating methods and an evaluation of groundwater recharge temperatures using dissolved-gas samples indicate that groundwater sampled in wells in the surficial aquifer in the vicinity of the mill is recharged locally by precipitation. Tritium/helium age dating methods found a "modern day" apparent age in water samples collected from springs in the study area surrounding the mill. This apparent age indicates localized recharge sources that potentially include artificial recharge of seepage from constructed wildlife refuge ponds near the mill. The stable oxygen isotope-ratio, delta oxygen-18, or δ(18O/16O), known as δ18O, and hydrogen isotope-ratio, delta deuterium, or δ(2H/1H), known as δD, data indicate that water discharging from Entrance Spring is isotopically enriched by evaporation and has a similar isotopic fingerprint as water from Recapture Reservoir, which is used as facilities water on the mill site. Water from Recapture

  9. Detection of depleted uranium in urine of veterans from the 1991 Gulf War.

    PubMed

    Gwiazda, R H; Squibb, K; McDiarmid, M; Smith, D

    2004-01-01

    American soldiers involved in "friendly fire" accidents during the 1991 Gulf War were injured with depleted-uranium-containing fragments or possibly exposed to depleted uranium via other routes such as inhalation, ingestion, and/or wound contamination. To evaluate the presence of depleted uranium in these soldiers eight years later, the uranium concentration and depleted uranium content of urine samples were determined by inductively coupled plasma mass spectrometry in (a) depleted uranium exposed soldiers with embedded shrapnel, (b) depleted uranium exposed soldiers with no shrapnel, and (c) a reference group of deployed soldiers not involved in the friendly fire incidents. Uranium isotopic ratios measured in many urine samples injected directly into the inductively coupled plasma mass spectrometer and analyzed at a mass resolution m/delta m of 300 appeared enriched in 235U with respect to natural abundance (0.72%) due to the presence of an interference of a polyatomic molecule of mass 234.81 amu that was resolved at a mass resolution m/delta m of 4,000. The 235U abundance measured on uranium separated from these urines by anion exchange chromatography was clearly natural or depleted. Urine uranium concentrations of soldiers with shrapnel were higher than those of the two other groups, and 16 out of 17 soldiers with shrapnel had detectable depleted uranium in their urine. In depleted uranium exposed soldiers with no shrapnel, depleted uranium was detected in urine samples of 10 out of 28 soldiers. The median uranium concentration of urines with depleted uranium from soldiers without shrapnel was significantly higher than in urines with no depleted uranium, though substantial overlap in urine uranium concentrations existed between the two groups. Accordingly, assessment of depleted uranium exposure using urine must rely on uranium isotopic analyses, since urine uranium concentration is not an unequivocal indicator of depleted uranium presence in soldiers with no

  10. Detection of depleted uranium in urine of veterans from the 1991 Gulf War.

    PubMed

    Gwiazda, R H; Squibb, K; McDiarmid, M; Smith, D

    2004-01-01

    American soldiers involved in "friendly fire" accidents during the 1991 Gulf War were injured with depleted-uranium-containing fragments or possibly exposed to depleted uranium via other routes such as inhalation, ingestion, and/or wound contamination. To evaluate the presence of depleted uranium in these soldiers eight years later, the uranium concentration and depleted uranium content of urine samples were determined by inductively coupled plasma mass spectrometry in (a) depleted uranium exposed soldiers with embedded shrapnel, (b) depleted uranium exposed soldiers with no shrapnel, and (c) a reference group of deployed soldiers not involved in the friendly fire incidents. Uranium isotopic ratios measured in many urine samples injected directly into the inductively coupled plasma mass spectrometer and analyzed at a mass resolution m/delta m of 300 appeared enriched in 235U with respect to natural abundance (0.72%) due to the presence of an interference of a polyatomic molecule of mass 234.81 amu that was resolved at a mass resolution m/delta m of 4,000. The 235U abundance measured on uranium separated from these urines by anion exchange chromatography was clearly natural or depleted. Urine uranium concentrations of soldiers with shrapnel were higher than those of the two other groups, and 16 out of 17 soldiers with shrapnel had detectable depleted uranium in their urine. In depleted uranium exposed soldiers with no shrapnel, depleted uranium was detected in urine samples of 10 out of 28 soldiers. The median uranium concentration of urines with depleted uranium from soldiers without shrapnel was significantly higher than in urines with no depleted uranium, though substantial overlap in urine uranium concentrations existed between the two groups. Accordingly, assessment of depleted uranium exposure using urine must rely on uranium isotopic analyses, since urine uranium concentration is not an unequivocal indicator of depleted uranium presence in soldiers with no

  11. Combining particle-tracking and geochemical data to assess public supply well vulnerability to arsenic and uranium

    USGS Publications Warehouse

    Hinkle, S.R.; Kauffman, L.J.; Thomas, M.A.; Brown, C.J.; McCarthy, K.A.; Eberts, S.M.; Rosen, Michael R.; Katz, B.G.

    2009-01-01

    Flow-model particle-tracking results and geochemical data from seven study areas across the United States were analyzed using three statistical methods to test the hypothesis that these variables can successfully be used to assess public supply well vulnerability to arsenic and uranium. Principal components analysis indicated that arsenic and uranium concentrations were associated with particle-tracking variables that simulate time of travel and water fluxes through aquifer systems and also through specific redox and pH zones within aquifers. Time-of-travel variables are important because many geochemical reactions are kinetically limited, and geochemical zonation can account for different modes of mobilization and fate. Spearman correlation analysis established statistical significance for correlations of arsenic and uranium concentrations with variables derived using the particle-tracking routines. Correlations between uranium concentrations and particle-tracking variables were generally strongest for variables computed for distinct redox zones. Classification tree analysis on arsenic concentrations yielded a quantitative categorical model using time-of-travel variables and solid-phase-arsenic concentrations. The classification tree model accuracy on the learning data subset was 70%, and on the testing data subset, 79%, demonstrating one application in which particle-tracking variables can be used predictively in a quantitative screening-level assessment of public supply well vulnerability. Ground-water management actions that are based on avoidance of young ground water, reflecting the premise that young ground water is more vulnerable to anthropogenic contaminants than is old ground water, may inadvertently lead to increased vulnerability to natural contaminants due to the tendency for concentrations of many natural contaminants to increase with increasing ground-water residence time.

  12. URANIUM EXTRACTION

    DOEpatents

    Harrington, C.D.; Opie, J.V.

    1958-07-01

    The recovery of uranium values from uranium ore such as pitchblende is described. The ore is first dissolved in nitric acid, and a water soluble nitrate is added as a salting out agent. The resulting feed solution is then contacted with diethyl ether, whereby the bulk of the uranyl nitrate and a portion of the impurities are taken up by the ether. This acid ether extract is then separated from the aqueous raffinate, and contacted with water causing back extractioa of the uranyl nitrate and impurities into the water to form a crude liquor. After separation from the ether extract, this crude liquor is heated to about 118 deg C to obtain molten uranyl nitrate hexahydratc. After being slightly cooled the uranyl nitrate hexahydrate is contacted with acid free diethyl ether whereby the bulk of the uranyl nitrate is dissolved into the ethcr to form a neutral ether solution while most of the impurities remain in the aqueous waste. After separation from the aqueous waste, the resultant ether solution is washed with about l0% of its volume of water to free it of any dissolved impurities and is then contacted with at least one half its volume of water whereby the uranyl nitrate is extracted into the water to form an aqueous product solution.

  13. Observations of anthropogenic cloud condensation nuclei

    NASA Technical Reports Server (NTRS)

    Hudson, James G.

    1990-01-01

    Cloud Condensation Nuclei (CCN) concentrations and spectral measurements obtained with the DRI instantaneous CCN spectrometer (Hudson, 1989) over the last few years are presented. The climatic importance of cloud microphysics has been pointed out. The particles which affect cloud microphysics are cloud condensation nuclei (CCN). The commonly-observed order of magnitude difference in cloud droplet concentrations between maritime and continental air masses (i.e., Squires, 1958) was determined to be caused by systematic differences in the concentrations of CCN between continental and maritime air masses (e.g., Twomey and Wojciechowski, 1969). Twomey (1977) first pointed out that cloud microphysics also affects the radiative properties of clouds. Thus continental and anthropogenic CCN could affect global temperature. Resolution of this Twomey effect requires answers to two questions - whether antropogenic CCN are a significant contribution to atmospheric CCN, and whether they are actually affecting cloud microphysics to an extent which is of climatic importance. The reasons for the contrast between continental and maritime CCN concentration are not understood. The question of the relative importance of anthropogenic CCN is addressed. These observations should shed light on this complex question although further research is being conducted in order to produce more quantitative answers. Accompanying CN measurements made with a TSI 3020 condensation nucleus (CN) counter are also presented.

  14. PRODUCTION OF URANIUM TETRACHLORIDE

    DOEpatents

    Calkins, V.P.

    1958-12-16

    A process is descrlbed for the production of uranium tetrachloride by contacting uranlum values such as uranium hexafluoride, uranlum tetrafluoride, or uranium oxides with either aluminum chloride, boron chloride, or sodium alumlnum chloride under substantially anhydrous condltlons at such a temperature and pressure that the chlorldes are maintained in the molten form and until the uranium values are completely converted to uranlum tetrachloride.

  15. PRODUCTION OF URANIUM MONOCARBIDE

    DOEpatents

    Powers, R.M.

    1962-07-24

    A method of making essentially stoichiometric uranium monocarbide by pelletizing a mixture of uranium tetrafluoride, silicon, and carbon and reacting the mixture at a temperature of approximately 1500 to 1700 deg C until the reaction goes to completion, forming uranium monocarbide powder and volatile silicon tetrafluoride, is described. The powder is then melted to produce uranium monocarbide in massive form. (AEC)

  16. Seasonal variability in anthropogenic halocarbon emissions.

    PubMed

    Gentner, Drew R; Miller, Angela M; Goldstein, Allen H

    2010-07-15

    Ambient concentrations of eight predominantly anthropogenic halocarbons were measured via in situ gas chromatography in California's South Coast air basin for both summer and fall during the 2005 Study of Organic Aerosols at Riverside (SOAR). Ongoing emissions of the banned halocarbons methylchloroform and CFC-11 were observed in the South Coast air basin, whereas CFC-113 emissions have effectively ceased. We estimate anthropogenic emissions in the South Coast air basin for methylchloroform, CFC-11, HCFC-141b, chloroform, tetrachloroethene (PCE), trichloroethylene (TCE), and dichloromethane based on regressions of halocarbon to carbon monoxide mixing ratios and carbon monoxide emission inventories. We estimate per capita methylchloroform and chloroform emissions in the South Coast air basin for the year 2005 to be 6.6 +/- 0.4 g/(person.year) and 19 +/- 1 g/(person.year), respectively. We compare our results to national emission estimates calculated from previous work; for several compounds, emissions in the South Coast air basin are significantly lower than national per capita emissions. We observed strong seasonal differences in anthropogenic emissions of methylchloroform and chloroform; emissions were 4.5 and 2.5 times greater in summer than in fall, respectively. Possible seasonal sources include landfills and water chlorination. We conclude that seasonal variability in methylchloroform emissions has not been included in previous inventories and may cause errors in methylchloroform emission estimates after the year 2000 and seasonally resolved inversion calculations of hydroxyl radical abundance. PMID:20536226

  17. Uranium Distribution along the Salinity Gradient

    NASA Astrophysics Data System (ADS)

    Yoon, C.; Yoon, H.; Seo, J.; Lee, J.; Chung, K.

    2006-12-01

    Uranium distribution has been examined in the estuarine waters of the Keum River, Korea. Water samples were collected along a salinity gradient, range from 0.2 to 31.5 psu. Dissolved uranium in the samples has been extracted by C-18 SPE cartridge after pre-treatment. Extraction of uranium by C-18 cartridge after complexation with APDC/DDDC shows about 90 % recovery. After concentration of sample onto C-18 cartridge, uranium complex has been sequentially extracted by 50 % and 100 % acetonitrile, respectively. Result shows good recovery efficiency at low pH (2.5 _ 3.0) during the pre-treatment of sample which was presumably related with destabilization of uranium-carbonate complex. In the estuary, uranium shows typical conservative behavior along the salinity gradient. The current result substantiates earlier reports that uranium is conservatively transported from the river to the ocean. Most of dissolved trace metals, except cadmium, decreased with increasing salinity in the estuary. Dissolved organic carbon also decreased along the salinity gradient. Copper was rapidly removed during the mixing with seawaters as a result of organic matter flocculation. Dissolved molybdenum, vanadium and uranium distribution in the estuary showed similarities that those concentration increase along the salinity gradient.

  18. Uranium in river water

    SciTech Connect

    Palmer, M.R. ); Edmond, J.M. )

    1993-10-01

    The concentration of dissolved uranium has been determined in over 250 river waters from the Orinoco, Amazon, and Ganges basins. Uranium concentrations are largely determined by dissolution of limestones, although weathering of black shales represents an important additional source in some basins. In shield terrains the level of dissolved U is transport limited. Data from the Amazon indicate that floodplains do not represent a significant source of U in river waters. In addition, the authors have determined dissolved U levels in forty rivers from around the world and coupled these data with previous measurements to obtain an estimate for the global flux of dissolved U to the oceans. The average concentration of U in river waters is 1.3 nmol/kg, but this value is biased by very high levels observed in the Ganges-Brahmaputra and Yellow rivers. When these river systems are excluded from the budget, the global average falls to 0.78 nmol/kg. The global riverine U flux lies in the range of 3-6 [times] 10[sup 7] mol/yr. The major uncertainty that restricts the accuracy of this estimate (and that of all other dissolved riverine fluxes) is the difficulty in obtaining representative samples from rivers which show large seasonal and annual variations in runoff and dissolved load.

  19. Uranium contents in plants and mushrooms grown on a uranium-contaminated site near Ronneburg in Eastern Thuringia/Germany.

    PubMed

    Baumann, Nils; Arnold, Thuro; Haferburg, Götz

    2014-01-01

    Uranium concentrations in cultivated (sunflower, sunchoke, potato) and native plants, plant compartment specimens, and mushrooms, grown on a test site within a uranium-contaminated area in Eastern Thuringia, were analyzed and compared. This test site belongs to the Friedrich-Schiller University Jena and is situated on the ground of a former but now removed uranium mine waste leaching heap. For determination of the U concentrations in the biomaterials, the saps of the samples were squeezed out by using an ultracentrifuge, after that, the uranium concentrations in the saps and the remaining residue were measured, using ICP-MS. The study further showed that uranium concentrations observed in plant compartment and mushroom fruiting bodies sap samples were always higher than their associated solid residue sample. Also, it was found that the detected uranium concentration in the root samples were always higher than were observed in their associated above ground biomass, e.g., in shoots, leaves, blossoms etc. The highest uranium concentration was measured with almost 40 ppb U in a fruiting body of a mushroom and in roots of butterbur. However, the detected uranium concentrations in plants and mushrooms collected in this study were always lower than in the associated surface and soil water of the test site, indicating that under the encountered natural conditions, none of the studied plant and mushroom species turned out to be a hyperaccumulator for uranium, which could have extracted uranium in sufficient amounts out of the uranium-contaminated soil. In addition, it was found that the detected uranium concentrations in the sap samples, despite being above the sensitivity limit, proved to be too low-in combination with the presence of fluorescence quenching substances, e.g., iron and manganese ions, and/or organic quenchers-to extract a useful fluorescence signal, which could have helped to identify the uranium speciation in plants.

  20. Plastics and other anthropogenic debris in freshwater birds from Canada.

    PubMed

    Holland, Erika R; Mallory, Mark L; Shutler, Dave

    2016-11-15

    Plastics in marine environments are a global environmental issue. Plastic ingestion is associated with a variety of deleterious health effects in marine wildlife, and is a focus of much international research and monitoring. However, little research has focused on ramifications of plastic debris for freshwater organisms, despite marine and freshwater environments often having comparable plastic concentrations. We quantified plastic and other anthropogenic debris in 350 individuals of 17 freshwater and one marine bird species collected across Canada. We determined freshwater birds' anthropogenic debris ingestion rates to be 11.1% across all species studied. This work establishes that plastics and other anthropogenic debris are a genuine concern for management of the health of freshwater ecosystems, and provides a baseline for the prevalence of plastic and other anthropogenic debris ingestion in freshwater birds in Canada, with relevance for many other locations.

  1. Plastics and other anthropogenic debris in freshwater birds from Canada.

    PubMed

    Holland, Erika R; Mallory, Mark L; Shutler, Dave

    2016-11-15

    Plastics in marine environments are a global environmental issue. Plastic ingestion is associated with a variety of deleterious health effects in marine wildlife, and is a focus of much international research and monitoring. However, little research has focused on ramifications of plastic debris for freshwater organisms, despite marine and freshwater environments often having comparable plastic concentrations. We quantified plastic and other anthropogenic debris in 350 individuals of 17 freshwater and one marine bird species collected across Canada. We determined freshwater birds' anthropogenic debris ingestion rates to be 11.1% across all species studied. This work establishes that plastics and other anthropogenic debris are a genuine concern for management of the health of freshwater ecosystems, and provides a baseline for the prevalence of plastic and other anthropogenic debris ingestion in freshwater birds in Canada, with relevance for many other locations. PMID:27476006

  2. DECONTAMINATION OF URANIUM

    DOEpatents

    Feder, H.M.; Chellew, N.R.

    1958-02-01

    This patent deals with the separation of rare earth and other fission products from neutron bombarded uranium. This is accomplished by melting the uranium in contact with either thorium oxide, maguesium oxide, alumnum oxide, beryllium oxide, or uranium dioxide. The melting is preferably carried out at from 1150 deg to 1400 deg C in an inert atmosphere, such as argon or helium. During this treatment a scale of uranium dioxide forms on the uranium whtch contains most of the fission products.

  3. Uranium reduction by Shewanella oneidensis MR-1 as a function of NaHCO3 concentration: surface complexation control of reduction kinetics.

    PubMed

    Sheng, Ling; Fein, Jeremy B

    2014-04-01

    It is crucial to determine the controls on the kinetics of U(VI) bioreduction in order to understand and model the fate and mobility of U in groundwater systems and also to enhance the effectiveness of U bioremediation strategies. In this study, we measured the rate of U(VI) reduction by Shewanella oneidensis strain MR-1 as function of NaHCO3 concentration. The experiments demonstrate that increasing concentrations of NaHCO3 in the system lead to slower U(VI) reduction kinetics. The NaHCO3 concentration also strongly affects the speciation of U(VI) on the bacterial cell envelope. We used a thermodynamic surface complexation modeling approach to determine the speciation and concentration of U(VI) adsorbed onto the bacteria as a function of the NaHCO3 concentration in the experimental systems. We observed a strong positive correlation between the measured U(VI) reduction rates and the calculated total concentration of U(VI) surface complexes formed on the bacterial cell envelope. This positive correlation indicates that the speciation and concentration of U(VI) adsorbed on the bacterial cell envelope control the kinetics of U(VI) bioreduction under the experimental conditions. The results of this study serve as a basis for developing speciation-based kinetic rate laws for enzymatic reduction of U(VI) by bacteria. PMID:24576101

  4. METHOD OF PROTECTIVELY COATING URANIUM

    DOEpatents

    Eubank, L.D.; Boller, E.R.

    1959-02-01

    A method is described for protectively coating uranium with zine comprising cleaning the U for coating by pickling in concentrated HNO/sub 3/, dipping the cleaned U into a bath of molten zinc between 430 to 600 C and containing less than 0 01% each of Fe and Pb, and withdrawing and cooling to solidify the coating. The zinccoated uranium may be given a; econd coating with another metal niore resistant to the corrosive influences particularly concerned. A coating of Pb containing small proportions of Ag or Sn, or Al containing small proportions of Si may be applied over the zinc coatings by dipping in molten baths of these metals.

  5. Uranium and Aluminosilicate Surface Precipitation Tests

    SciTech Connect

    Hu, M.Z.

    2002-11-27

    The 2H evaporator at the Savannah River Site has been used to treat an aluminum-rich waste stream from canyon operations and a silicon-rich waste stream from the Defense Waste Processing Facility. The formation of aluminosilicate scale in the evaporator has caused significant operational problems. Because uranium has been found to accumulate in the aluminosilicate solids, the scale deposition has introduced criticality concerns as well. The objective of the tests described in this report is to determine possible causes of the uranium incorporation in the evaporator scale materials. The scope of this task is to perform laboratory experiments with simulant solutions to determine if (1) uranium can be deposited on the surfaces of various sodium aluminosilicate (NAS) forms and (2) aluminosilicates can form on the surfaces of uranium-containing solids. Batch experiments with simulant solutions of three types were conducted: (1) contact of uranium solutions/sols with NAS coatings on stainless steel surfaces, (2) contact of uranium solutions with NAS particles, and (3) contact of precipitated uranium-containing particles with solutions containing aluminum and silicon. The results show that uranium can be incorporated in NAS solids through encapsulation in bulk agglomerated NAS particles of different phases (amorphous, zeolite A, sodalite, and cancrinite) as well as through heterogeneous deposition on the surfaces of NAS coatings (amorphous and cancrinite) grown on stainless steel. The results also indicate that NAS particles can grow on the surfaces of precipitated uranium solids. Particularly notable for evaporator operations is the finding that uranium solids can form on existing NAS scale, including cancrinite solids. If NAS scale is present, and uranium is in sufficient concentration in solution to precipitate, a portion of the uranium can be expected to become associated with the scale. The data obtained to date on uranium-NAS affinity are qualitative. A necessary

  6. URANIUM DECONTAMINATION

    DOEpatents

    Buckingham, J.S.; Carroll, J.L.

    1959-12-22

    A process is described for reducing the extractability of ruthenium, zirconium, and niobium values into hexone contained in an aqueous nitric acid uranium-containing solution. The solution is made acid-deficient, heated to between 55 and 70 deg C, and at that temperature a water-soluble inorganic thiosulfate is added. By this, a precipitate is formed which carries the bulk of the ruthenium, and the remainder of the ruthenium as well as the zirconium and niobium are converted to a hexone-nonextractable form. The rutheniumcontaining precipitate can either be removed from the solu tion or it can be dissolved as a hexone-non-extractable compound by the addition of sodium dichromate prior to hexone extraction.

  7. Uptake of uranium by aquatic plants growing in fresh water ecosystem around uranium mill tailings pond at Jaduguda, India.

    PubMed

    Jha, V N; Tripathi, R M; Sethy, N K; Sahoo, S K

    2016-01-01

    Concentration of uranium was determined in aquatic plants and substrate (sediment or water) of fresh water ecosystem on and around uranium mill tailings pond at Jaduguda, India. Aquatic plant/substrate concentration ratios (CRs) of uranium were estimated for different sites on and around the uranium mill tailings disposal area. These sites include upstream and downstream side of surface water sources carrying the treated tailings effluent, a small pond inside tailings disposal area and residual water of this area. Three types of plant groups were investigated namely algae (filamentous and non-filamentous), other free floating & water submerged and sediment rooted plants. Wide variability in concentration ratio was observed for different groups of plants studied. The filamentous algae uranium concentration was significantly correlated with that of water (r=0.86, p<0.003). For sediment rooted plants significant correlation was found between uranium concentration in plant and the substrate (r=0.88, p<0.001). Both for other free floating species and sediment rooted plants, uranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (p<0.01). Filamentous algae, Jussiaea and Pistia owing to their high bioproductivity, biomass, uranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent.

  8. A graphene oxide/amidoxime hydrogel for enhanced uranium capture

    PubMed Central

    Wang, Feihong; Li, Hongpeng; Liu, Qi; Li, Zhanshuang; Li, Rumin; Zhang, Hongsen; Liu, Lianhe; Emelchenko, G. A.; Wang, Jun

    2016-01-01

    The efficient development of selective materials for the recovery of uranium from nuclear waste and seawater is necessary for their potential application in nuclear fuel and the mitigation of nuclear pollution. In this work, a graphene oxide/amidoxime hydrogel (AGH) exhibits a promising adsorption performance for uranium from various aqueous solutions, including simulated seawater. We show high adsorption capacities (Qm = 398.4 mg g−1) and high % removals at ppm or ppb levels in aqueous solutions for uranium species. In the presence of high concentrations of competitive ions such as Mg2+, Ca2+, Ba2+ and Sr2+, AGH displays an enhanced selectivity for uranium. For low uranium concentrations in simulated seawater, AGH binds uranium efficiently and selectively. The results presented here reveal that the AGH is a potential adsorbent for remediating nuclear industrial effluent and adsorbing uranium from seawater. PMID:26758649

  9. A graphene oxide/amidoxime hydrogel for enhanced uranium capture

    NASA Astrophysics Data System (ADS)

    Wang, Feihong; Li, Hongpeng; Liu, Qi; Li, Zhanshuang; Li, Rumin; Zhang, Hongsen; Liu, Lianhe; Emelchenko, G. A.; Wang, Jun

    2016-01-01

    The efficient development of selective materials for the recovery of uranium from nuclear waste and seawater is necessary for their potential application in nuclear fuel and the mitigation of nuclear pollution. In this work, a graphene oxide/amidoxime hydrogel (AGH) exhibits a promising adsorption performance for uranium from various aqueous solutions, including simulated seawater. We show high adsorption capacities (Qm = 398.4 mg g‑1) and high % removals at ppm or ppb levels in aqueous solutions for uranium species. In the presence of high concentrations of competitive ions such as Mg2+, Ca2+, Ba2+ and Sr2+, AGH displays an enhanced selectivity for uranium. For low uranium concentrations in simulated seawater, AGH binds uranium efficiently and selectively. The results presented here reveal that the AGH is a potential adsorbent for remediating nuclear industrial effluent and adsorbing uranium from seawater.

  10. Uranium in drinking water: Document for public comment

    SciTech Connect

    1999-09-01

    The paper presents background information for discussion related to a proposed guideline for the maximum permissible concentration of uranium in drinking water. Information is provided on the following: identity, use, and sources of uranium in the environment; uranium analysis methods and water treatment technology; human exposure to uranium in water, food, and air; health effects (chemical aspects, not radiological) including uranium absorption, distribution and excretion, toxicology, and mutagenicity; and classification and assessment of health risk. Finally, the rationale for the proposed guideline is explained. The appendix contains a report on the occurrence of uranium in provincial and territorial water supplies and costs of treatment for supplies containing uranium at concentrations in excess of the recommended maximum.

  11. Comparison of the distributions of the actinides uranium and thorium with the lanthanide gadolinium in the tissues and eggs of Japanese quail: concentrations of uranium in feeds and foods

    SciTech Connect

    Robinson, G.A.; Wasnidge, D.C.; Floto, F.

    1984-05-01

    Japanese quail were given UCl/sub 3/, UO/sub 2/ (NO/sub 3/)/sub 2/, Th(NO/sub 3/)/sub 4/, or GdCl/sub 3/ (/sub 153/Gd -labeled) intravenously in aqueous solution. Distribution of Th among the tissues was as for Gd; distributions of U(III) and U(VI) were markedly different. Whole body losses by 18 hr were: females, U 24%, Th 14%, Gd 4%; males, U 72%, Th 23%, Gd 1%. Cumulative depositions in yolks of eggs laid over 8 days were: U(III) 1.9%, U(VI) 1.7%, Th 57.3%, Gd 46.8%. The distribution of U in quail may be atypical of actinides. Concentrations of U in various feeds, foods, and mineral supplements ranged from 169 micrograms/g in a phosphate fertilizer for farm use to below the lower detectable limit of .01 microgram/g in many foods intended for human use. Two batches of the game bird laying ration supplied to the quail colony contained 3.05 and 4.42 micrograms U/g. Body burdens of 3.5 micrograms U/bird for noninjected quail were attributed to the U content of this feed.

  12. Seasonal, anthropogenic, air mass, and meteorological influences on the atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs): Evidence for the importance of diffuse combustion sources

    SciTech Connect

    Lee, R.G.M.; Green, N.J.L.; Lohmann, R.; Jones, K.C.

    1999-09-01

    Sampling programs were undertaken to establish air polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations at a semirural site on the northwest coast of England in autumn and summer and to investigate factors causing their variability. Changing source inputs, meteorological parameters, air masses, and the impact of a festival when it is customary to light fireworks and bonfires were investigated. Various lines of evidence from the study point to diffuse, combustion-related sources being a major influence on ambient air concentrations. Higher PCDD/F concentrations were generally associated with air masses that had originated and moved over land, particularly during periods of low ambient temperature. Low concentrations were associated with air masses that had arrived from the Atlantic Ocean/Irish Sea to the west of the sampling site and had little or no contact with urban/industrialized areas. Concentrations in the autumn months were 2 to 10 times higher than those found in the summer.

  13. Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)

    SciTech Connect

    AL-Areqi, Wadeeah M. Majid, Amran Ab. Sarmani, Sukiman

    2014-02-12

    Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.

  14. National Uranium Resource Evaluation: Joplin Quadrangle, Missouri and Kansas

    SciTech Connect

    Derby, J.R.; Upshaw, L.P.; Carter, E.O.; Roach, L.F.; Roach, D.G.

    1982-08-01

    Reconnaissance and detailed geologic and radiometric investigations were conducted throughout the Joplin Quadrangle, Missouri and Kansas, to evaluate the uranium favorability using National Uranium Resource Evaluation criteria. Surface and subsurface studies were augmented by aerial radiometric surveys and hydrogeochemical and stream-sediment reconnaissance studies. Results of the investigations indicate that black shales of Desmoinesian and Missourian (Pennsylvanian) age are environments favorable for the deposition of uranium. The uranium is concentrated in phosphate nodules within these black shales. Environments considered unfavorable for uranium deposits are fluvial placers, coals, limestones, all sandstones, peridotite, granites, the Pennsylvanian-Mississippian unconformity, and vein-type deposits in sedimentary rocks.

  15. Plant induced changes in concentrations of caesium, strontium and uranium in soil solution with reference to major ions and dissolved organic matter.

    PubMed

    Takeda, Akira; Tsukada, Hirofumi; Takaku, Yuichi; Akata, Naofumi; Hisamatsu, Shun'ichi

    2008-06-01

    For a better understanding of the soil-to-plant transfer of radionuclides, their behavior in the soil solution should be elucidated, especially at the interface between plant roots and soil particles, where conditions differ greatly from the bulk soil because of plant activity. This study determined the concentration of stable Cs and Sr, and U in the soil solution, under plant growing conditions. The leafy vegetable komatsuna (Brassica rapa L.) was cultivated for 26 days in pots, where the rhizosphere soil was separated from the non-rhizosphere soil by a nylon net screen. The concentrations of Cs and Sr in the rhizosphere soil solution decreased with time, and were controlled by K+NH(4)(+) and Ca, respectively. On the other hand, the concentration of U in the rhizosphere soil solution increased with time, and was related to the changes of DOC; however, this relationship was different between the rhizosphere and non-rhizosphere soil.

  16. Chemical and Radiological Toxicity of Uranium and Its Compounds

    SciTech Connect

    Tansky, R.R.

    2001-07-26

    The concentration of uranyl nitrate required to deliver the radiation dose limit for soluble uranium compounds is larger than the toxicity-based concentration limits. Therefore, for soluble uranium compounds, health consequences of exposure are primarily due to their chemical toxicity. For insoluble compounds of uranium, health consequences (e.g., fibrosis and/or carcinogenesis of the lung) are primarily due to irradiation of pulmonary tissues from inhaled respirable particles.

  17. Uranium in Kosovo's drinking water.

    PubMed

    Berisha, Fatlume; Goessler, Walter

    2013-11-01

    The results of this paper are an initiation to capture the drinking water and/or groundwater elemental situation in the youngest European country, Kosovo. We aim to present a clear picture of the natural uranium concentration in drinking water and/or groundwater as it is distributed to the population of Kosovo. Nine hundred and fifty-one (951) drinking water samples were analyzed by inductively coupled plasma mass spectrometry (ICPMS). The results are the first countrywide interpretation of the uranium concentration in drinking water and/or groundwater, directly following the Kosovo war of 1999. More than 98% of the samples had uranium concentrations above 0.01 μg L(-1), which was also our limit of quantification. Concentrations up to 166 μg L(-1) were found with a mean of 5 μg L(-1) and median 1.6 μg L(-1) were found. Two point six percent (2.6%) of the analyzed samples exceeded the World Health Organization maximum acceptable concentration of 30 μg L(-1), and 44.2% of the samples exceeded the 2 μg L(-1) German maximum acceptable concentrations recommended for infant food preparations.

  18. PROCESS FOR SEGREGATING URANIUM FROM PLUTONIUM AND FISSION-PRODUCT CONTAMINATION

    DOEpatents

    Ellison, C.V.; Runion, T.C.

    1961-06-27

    An aqueous nitric acid solution containing uranium, plutonium, and fission product values is contacted with an organic extractant comprised of a trialkyl phosphate and an organic diluent. The relative amounts of trialkyl phosphate and uranium values are controlled to achieve a concentration of uranium values in the organic extractant of at least 0.35 moles uranium per mole of trialkyl phosphate, thereby preferentially extracting uranium values into the organic extractant.

  19. Uzbekistan unveiled. [Uranium production to commence

    SciTech Connect

    Mazurkevich, A.P.

    1993-05-01

    Through centuries of revolution, war and strife, the people of Uzbekistan have built a reputation as skilled and tenacious merchants. Since antiquity, when the Silk Road from China turned toward Europe at Smarakand, they have been master traders of such valuable commodities as cotton, fruits, vegetables, spices and gold. Now, they're about to introduce another of their specialties to the world: Uranium. Uranium mining in the country is controlled by a new, independent company, the Kizilkumredmetzoloto, parent of the Navoi Mining Metallurgy Combine [NMMC]. Established in 1958 at the height of the Cold War, when uranium mining for military stockpiles got started in earnest, Navoi was wholly owned by the USSR's Ministry of Medium Machine Building. Up until 1991, virtually all of Navoi's uranium production, strictly in the form of uranium concentrates, was used for either military purposes or for nuclear power plants within the former Soviet Union. The republic exerted no control over the final destination of its uranium. All production and operating decisions for Navoi's mines were dictated by the Soviet Union's Ministry of Atomic Power Industry [MAPI], which developed annual quotas for uranium production in each republic of the country. Uranium from the republics was sold to Techsnabexport [Tenex], the distribution and marketing arm of MAPI. Exports to other countries were handled strictly by Tenex.

  20. Process for electroslag refining of uranium and uranium alloys

    DOEpatents

    Lewis, P.S. Jr.; Agee, W.A.; Bullock, J.S. IV; Condon, J.B.

    1975-07-22

    A process is described for electroslag refining of uranium and uranium alloys wherein molten uranium and uranium alloys are melted in a molten layer of a fluoride slag containing up to about 8 weight percent calcium metal. The calcium metal reduces oxides in the uranium and uranium alloys to provide them with an oxygen content of less than 100 parts per million. (auth)

  1. URANIUM RECOVERY AND PURIFICATION PROCESS AND PRODUCTION OF HIGH PURITY URANIUM TETRAFLUORIDE

    DOEpatents

    Bailes, R.H.; Long, R.S.; Grinstead, R.R.

    1957-09-17

    A process is described wherein an anionic exchange technique is employed to separate uramium from a large variety of impurities. Very efficient and economical purification of contamimated uranium can be achieved by treatment of the contaminated uranium to produce a solution containing a high concentration of chloride. Under these conditions the uranium exists as an aniomic chloride complex. Then the uranium chloride complex is adsorbed from the solution on an aniomic exchange resin, whereby a portion of the impurities remain in the solution and others are retained with the uramium by the resin. The adsorbed impurities are then removed by washing the resin with pure concentrated hydrochloric acid, after which operation the uranium is eluted with pure water yielding an acidic uranyl chloride solution of high purity.

  2. URANIUM RECOVERY PROCESS

    DOEpatents

    Bailes, R.H.; Long, R.S.; Olson, R.S.; Kerlinger, H.O.

    1959-02-10

    A method is described for recovering uranium values from uranium bearing phosphate solutions such as are encountered in the manufacture of phosphate fertilizers. The solution is first treated with a reducing agent to obtain all the uranium in the tetravalent state. Following this reduction, the solution is treated to co-precipitate the rcduced uranium as a fluoride, together with other insoluble fluorides, thereby accomplishing a substantially complete recovery of even trace amounts of uranium from the phosphate solution. This precipitate usually takes the form of a complex fluoride precipitate, and after appropriate pre-treatment, the uranium fluorides are leached from this precipitate and rccovered from the leach solution.

  3. PRODUCTION OF PURIFIED URANIUM

    DOEpatents

    Burris, L. Jr.; Knighton, J.B.; Feder, H.M.

    1960-01-26

    A pyrometallurgical method for processing nuclear reactor fuel elements containing uranium and fission products and for reducing uranium compound; to metallic uranium is reported. If the material proccssed is essentially metallic uranium, it is dissolved in zinc, the sulution is cooled to crystallize UZn/sub 9/ , and the UZn/sub 9/ is distilled to obtain uranium free of fission products. If the material processed is a uranium compound, the sollvent is an alloy of zinc and magnesium and the remaining steps are the same.

  4. Anthropogenic Aerosols and the Evolution of U.S. Droughts

    NASA Astrophysics Data System (ADS)

    Leibensperger, E. M.; Cazavilan, E. J.

    2014-12-01

    Anthropogenic aerosols interact with solar radiation to influence regional to global climate. Trends in aerosol concentrations have impacted the evolution of surface air temperatures and the hydrological cycle over the last 150 years, but the magnitude of influence and any role in shaping extreme events remains uncertain. We use a general circulation model (GISS GCM ModelE) to study the impact of anthropogenic aerosols on the formation of two potential U.S. droughts. Two periods are analyzed, the 1930s Dust Bowl and the 1970s "missed drought". Each period realized ocean conditions ripe for the formation of central U.S. drought, but experienced differing composition and amounts of anthropogenic aerosol forcing. Simulations forced solely by observed sea surface temperature and sea ice distributions reveal drier and warmer conditions in the central U.S. (annual decreases of up to 0.5 mm/day and warming of 0.5°C). We find that anthropogenic aerosols of the 1930s, containing a significant warming component from U.S. black carbon, exacerbated the warm conditions (0.2°C) and provided slightly drier conditions. In contrast, anthropogenic aerosols of the 1970s, containing a large cooling component from U.S. sulfate, reduced annual precipitation deficits and lowered temperatures by up to 0.4°C. Our results showcase the importance of anthropogenic aerosol forcing in the evolution of U.S. droughts.

  5. Concentration of Beryllium (Be) and Depleted Uranium (DU) in Marine Fauna and Sediment Samples from Illeginni and Boggerik Islands at Kwajalein Atoll

    SciTech Connect

    Robison, W L; Hamilton, T F; Martinelli, R E; Kehl, S R; Lindman, T R

    2005-02-24

    Lawrence Livermore National Laboratory (LLNL) personnel have supported US Air Force (USAF) ballistic missile flight tests for about 15 years for Peacekeeper and Minuteman missiles launched at Vandenberg Air Force Base (VAFB). Associated re-entry vehicles (RV's) re-enter at Regan Test Site (RTS) at the US Army base at Kwajalein Atoll (USAKA) where LLNL has supported scoring, recovery operations for RV materials, and environmental assessments. As part of ongoing USAF ballistic missile flight test programs, LLNL is participating in an updated EA being written for flights originating at VFAB. Marine fauna and sediments (beach-sand samples) were collected by US Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), and LLNL at Illeginni Island and Boggerik Island (serving as a control site) at Kwajalein Atoll. Data on the concentration of DU (hereafter, U) and Be in collected samples was requested by USFWS and NMFS to determine whether or not U and Be in RV's entering the Illeginni area are increasing U and Be concentrations in marine fauna and sediments. LLNL agreed to do the analyses for U and Be in support of the EA process and provide a report of the results. There is no statistically significant difference in the concentration of U and Be in six species of marine fauna from Illeginni and Boggerik Islands (p - 0.14 for U and p = 0.34 for Be). Thus, there is no evidence that there has been any increase in U and Be concentrations in marine fauna as a result of the missile flight test program. Concentration of U in beach sand at Illeginni is the same as soil and beach sand in the rest of the Marshall Islands and again reflects an insignificant impact from the flight test program. Beach sand from Illeginni has a mean concentration of Be higher than that from the control site, Boggeik Island. Seven of 21 samples from Ileginni had detectable Be. Four samples had a concentration of Be ranging from 4 to 7 ng g {sup -1} (4 to 7 parts per billion (ppb

  6. Climate forcing by anthropogenic aerosols.

    PubMed

    Charlson, R J; Schwartz, S E; Hales, J M; Cess, R D; Coakley, J A; Hansen, J E; Hofmann, D J

    1992-01-24

    Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of shortwavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

  7. Climate Forcing by Anthropogenic Aerosols

    NASA Astrophysics Data System (ADS)

    Charlson, R. J.; Schwartz, S. E.; Hales, J. M.; Cess, R. D.; Coakley, J. A., Jr.; Hansen, J. E.; Hofmann, D. J.

    1992-01-01

    Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

  8. Climate forcing by anthropogenic aerosols

    NASA Technical Reports Server (NTRS)

    Charlson, R. J.; Schwartz, S. E.; Hales, J. M.; Cess, R. D.; Coakley, J. A., Jr.; Hansen, J. E.; Hofmann, D. J.

    1992-01-01

    Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol, in particular, has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

  9. Uranium Sequestration by Aluminum Phosphate Minerals in Unsaturated Soils

    SciTech Connect

    Jerden, James L. Jr.

    2007-07-01

    A mineralogical and geochemical study of soils developed from the unmined Coles Hill uranium deposit (Virginia) was undertaken to determine how phosphorous influences the speciation of uranium in an oxidizing soil/saprolite system typical of the eastern United States. This paper presents mineralogical and geochemical results that identify and quantify the processes by which uranium has been sequestered in these soils. It was found that uranium is not leached from the saturated soil zone (saprolites) overlying the deposit due to the formation of a sparingly soluble uranyl phosphate mineral of the meta-autunite group. The concentration of uranium in the saprolites is approximately 1000 mg uranium per kg of saprolite. It was also found that a significant amount of uranium was retained in the unsaturated soil zone overlying uranium-rich saprolites. The uranium concentration in the unsaturated soils is approximately 200 mg uranium per kg of soil (20 times higher than uranium concentrations in similar soils adjacent to the deposit). Mineralogical evidence indicates that uranium in this zone is sequestered by a barium-strontium-calcium aluminum phosphate mineral of the crandallite group (gorceixite). This mineral is intimately inter-grown with iron and manganese oxides that also contain uranium. The amount of uranium associated with both the aluminum phosphates (as much as 1.4 weight percent) has been measured by electron microprobe micro-analyses and the geochemical conditions under which these minerals formed has been studied using thermodynamic reaction path modeling. The geochemical data and modeling results suggest the meta-autunite group minerals present in the saprolites overlying the deposit are unstable in the unsaturated zone soils overlying the deposit due to a decrease in soil pH (down to a pH of 4.5) at depths less than 5 meters below the surface. Mineralogical observations suggest that, once exposed to the unsaturated environment, the meta-autunite group

  10. Reconciling anthropogenic climate change with observed temperature 1998-2008.

    PubMed

    Kaufmann, Robert K; Kauppi, Heikki; Mann, Michael L; Stock, James H

    2011-07-19

    Given the widely noted increase in the warming effects of rising greenhouse gas concentrations, it has been unclear why global surface temperatures did not rise between 1998 and 2008. We find that this hiatus in warming coincides with a period of little increase in the sum of anthropogenic and natural forcings. Declining solar insolation as part of a normal eleven-year cycle, and a cyclical change from an El Nino to a La Nina dominate our measure of anthropogenic effects because rapid growth in short-lived sulfur emissions partially offsets rising greenhouse gas concentrations. As such, we find that recent global temperature records are consistent with the existing understanding of the relationship among global surface temperature, internal variability, and radiative forcing, which includes anthropogenic factors with well known warming and cooling effects.

  11. Reconciling anthropogenic climate change with observed temperature 1998–2008

    PubMed Central

    Kaufmann, Robert K.; Kauppi, Heikki; Mann, Michael L.; Stock, James H.

    2011-01-01

    Given the widely noted increase in the warming effects of rising greenhouse gas concentrations, it has been unclear why global surface temperatures did not rise between 1998 and 2008. We find that this hiatus in warming coincides with a period of little increase in the sum of anthropogenic and natural forcings. Declining solar insolation as part of a normal eleven-year cycle, and a cyclical change from an El Nino to a La Nina dominate our measure of anthropogenic effects because rapid growth in short-lived sulfur emissions partially offsets rising greenhouse gas concentrations. As such, we find that recent global temperature records are consistent with the existing understanding of the relationship among global surface temperature, internal variability, and radiative forcing, which includes anthropogenic factors with well known warming and cooling effects. PMID:21730180

  12. Electrolytic process for preparing uranium metal

    DOEpatents

    Haas, Paul A.

    1990-01-01

    An electrolytic process for making uranium from uranium oxide using Cl.sub.2 anode product from an electrolytic cell to react with UO.sub.2 to form uranium chlorides. The chlorides are used in low concentrations in a melt comprising fluorides and chlorides of potassium, sodium and barium in the electrolytic cell. The electrolysis produces Cl.sub.2 at the anode that reacts with UO.sub.2 in the feed reactor to form soluble UCl.sub.4, available for a continuous process in the electrolytic cell, rather than having insoluble UO.sub.2 fouling the cell.

  13. Capstone Depleted Uranium Aerosols: Generation and Characterization

    SciTech Connect

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  14. NICKEL COATED URANIUM ARTICLE

    DOEpatents

    Gray, A.G.

    1958-10-01

    Nickel coatings on uranium and various methods of obtaining such coatings are described. Specifically disclosed are such nickel or nickel alloy layers as barriers between uranium and aluminum- silicon, chromium, or copper coatings.

  15. Uranium from phosphate ores

    SciTech Connect

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant.

  16. Effectiveness of chelation therapy with time after acute uranium intoxication

    SciTech Connect

    Domingo, J.L.; Ortega, A.; Llobet, J.M.; Corbella, J. )

    1990-01-01

    The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy.

  17. PRODUCTION OF URANIUM TETRAFLUORIDE

    DOEpatents

    Shaw, W.E.; Spenceley, R.M.; Teetzel, F.M.

    1959-08-01

    A method is presented for producing uranium tetrafluoride from the gaseous hexafluoride by feeding the hexafluoride into a high temperature zone obtained by the recombination of molecularly dissociated hydrogen. The molal ratio of hydrogen to uranium hexnfluoride is preferably about 3 to 1. Uranium tetrafluoride is obtained in a finely divided, anhydrous state.

  18. The Global Land-Ocean Temperature Index in Relation to Sunspot Number, the Atlantic Multidecadal Oscillation Index, the Mauna Loa Atmospheric Concentration of CO2, and Anthropogenic Carbon Emissions

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2013-01-01

    Global warming/climate change has been a subject of scientific interest since the early 19th century. In particular, increases in the atmospheric concentration of carbon dioxide (CO2) have long been thought to account for Earth's increased warming, although the lack of a dependable set of observational data was apparent as late as the mid 1950s. However, beginning in the late 1950s, being associated with the International Geophysical Year, the opportunity arose to begin accurate continuous monitoring of the Earth's atmospheric concentration of CO2. Consequently, it is now well established that the atmospheric concentration of CO2, while varying seasonally within any particular year, has steadily increased over time. Associated with this rising trend in the atmospheric concentration of CO2 is a rising trend in the surface-air and sea-surface temperatures (SSTs). This Technical Publication (TP) examines the statistical relationships between 10-year moving averages (10-yma) of the Global Land-Ocean Temperature Index (GLOTI), sunspot number (SSN), the Atlantic Multidecadal Oscillation (AMO) index, and the Mauna Loa CO2 (MLCO2) index for the common interval 1964-2006, where the 10-yma values are used to indicate trends in the data. Scatter plots using the 10-yma values between GLOTI and each of the other parameters are determined, both as single-variate and multivariate fits. Scatter plots are also determined for MLCO2 using single-variate and bivariate (BV) fits, based on the GLOTI alone and the GLOTI in combination with the AMO index. On the basis of the inferred preferential fits for MLCO2, estimates for MLCO2 are determined for the interval 1885-1964, thereby yielding an estimate of the preindustrial level of atmospheric concentration of CO2. Lastly, 10-yma values of MLCO2 are compared against 10-yma estimates of the total carbon emissions (TCE) to determine the likelihood that manmade sources of carbon emissions are indeed responsible for the recent warming now

  19. Selective leaching of uranium from uranium-contaminated soils

    SciTech Connect

    Francis, C.W.; Mattus, A.J.; Farr, L.L.; Lee, S.Y.; Elless, M.P. |

    1993-06-01

    Three soils and a sediment contaminated with uranium were used to determine the effectiveness of sodium carbonate and citric acid leaching to decontaminate or remove uranium to acceptable regulatory levels. The objective was to selectively extract uranium using a soil washing/extraction process without seriously degrading the soil`s physicochemical characteristics or generating a secondary waste form that would be difficult to manage and/or dispose of. Two of the soils were surface soils from the DOE facility formerly called the Feed Materials Production Center (FMPC) at Fernald, Ohio. One of the soils is from near the Plant 1 storage pad and the other soil was taken from near a waste incinerator used to burn low-level contaminated trash. The third soil was a surface soil from an area formally used as a landfarm for the treatment of spent oils at the Oak Ridge Y-12 Plant. The sediment sample was material sampled from a storm sewer sediment trap at the Oak Ridge Y-12 Plant. Uranium concentrations in the Fernald soils ranged from 450 to 550 {mu}g U/g of soil while the samples from the Y-12 Plant ranged from 150 to 200 {mu}g U/g of soil.

  20. Selection of Stream Insect Larvae for Indicating Anthropogenic Impact

    EPA Science Inventory

    This study examined the total mercury concentrations, [Hg], and 15N values in macro-invertebrates collected from 35 stream sites in Rhode Island, USA, to determine the organism groups most suitable for use as indicators of anthropogenic impact. Site selection was designed to cov...

  1. Estimating animal mortality from anthropogenic hazards

    EPA Science Inventory

    Carcass searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. Para...

  2. The role of partial melting and syn-orogenic deformation in the pre-concentration of uranium and thorium. The example of the CAGE District (Northern Quebec).

    NASA Astrophysics Data System (ADS)

    Trap, Pierre; Goncalves, Philippe; Durand, Cyril; Marquer, Didier; Feybesse, Jean-Louis; Richard, Yoann; Lacroix, Brice; Caillet, Yoann; Paquette, Jean-Louis

    2015-04-01

    This contribution aims to discuss the relationships between metamorphism, deformation and U-Th mineralization within the orogenic crust, from millimeter to kilometer scale and during the whole P-T-t evolution. The study area is the CAGE district along the paleoproterozoic Torngat orogen (Northern Quebec) made of 2.1 Ga metasedimentary rocks, marbles and paragneisses, deposited upon a 2.5 Ga orthogneissic basement. Several types of U-Th mineralizations have been reported within the middle crust highly metamorphosed and deformed during the Torgnat orogeny (1.9-1.8 Ga). An integrated study with field, geophysical, structural, petrological, geochemical and thermochronological analyses enable a reconstitution of the tectono-metamorphic setting of these U-Th mineralizations and of the mechanism responsible for their pre-concentration into the orogenic crust. The petrological analysis allows us to build a clockwise P-T-t-D evolution with peak pressure conditions at 7.5 - 10 kbar and 725 - 750 ° C and peak temperature conditions at 5-6 kbar and 800-850°C. This high grade metamorphism and widespread partial melting developed within a single dextral transpressive regime. The structural analysis suggests strain partitioning responsible for a S-C-C' like architecture observed at all scales. Aeromagnetic, radiometric and field observations revealed that U-Th mineralizations are mainly focused along the kilometer scale C and C'-type shear zones. The age of crustal partial melting was constrained by U-Pb LA-ICP-MS analyses on zircon and monazite within migmatitic paragneiss and orthogneiss between 1841 ± 5 and 1828 ± 7 Ma. Younger U-Pb ages at around 1810-1750 Ma have been reported on monazite and titanites within the crustal scale shear bands (C and C' like). Results obtained on mylonitic metacarbonaceous and metapelites within kilometer scale shear zones suggest that late shearing formed during retrograde evolution at decreasing temperature after peak metamorphism. The δ13

  3. Uranium isotopes in ground water as a prospecting technique

    SciTech Connect

    Cowart, J.B.; Osmond, J.K.

    1980-02-01

    The isotopic concentrations of dissolved uranium were determined for 300 ground water samples near eight known uranium accumulations to see if new approaches to prospecting could be developed. It is concluded that a plot of /sup 234/U//sup 238/U activity ratio (A.R.) versus uranium concentration (C) can be used to identify redox fronts, to locate uranium accumulations, and to determine whether such accumulations are being augmented or depleted by contemporary aquifer/ground water conditions. In aquifers exhibiting flow-through hydrologic systems, up-dip ground water samples are characterized by high uranium concentration values (> 1 to 4 ppB) and down-dip samples by low uranium concentration values (less than 1 ppB). The boundary between these two regimes can usually be identified as a redox front on the basis of regional water chemistry and known uranium accumulations. Close proximity to uranium accumulations is usually indicated either by very high uranium concentrations in the ground water or by a combination of high concentration and high activity ratio values. Ground waters down-dip from such accumulations often exhibit low uranium concentration values but retain their high A.R. values. This serves as a regional indicator of possible uranium accumulations where conditions favor the continued augmentation of the deposit by precipitation from ground water. Where the accumulation is being dispersed and depleted by the ground water system, low A.R. values are observed. Results from the Gulf Coast District of Texas and the Wyoming districts are presented.

  4. Enhanced Uranium Immobilization and Reduction by Geobacter sulfurreducens Biofilms

    PubMed Central

    Cologgi, Dena L.; Speers, Allison M.; Bullard, Blair A.; Kelly, Shelly D.

    2014-01-01

    Biofilms formed by dissimilatory metal reducers are of interest to develop permeable biobarriers for the immobilization of soluble contaminants such as uranium. Here we show that biofilms of the model uranium-reducing bacterium Geobacter sulfurreducens immobilized substantially more U(VI) than planktonic cells and did so for longer periods of time, reductively precipitating it to a mononuclear U(IV) phase involving carbon ligands. The biofilms also tolerated high and otherwise toxic concentrations (up to 5 mM) of uranium, consistent with a respiratory strategy that also protected the cells from uranium toxicity. The enhanced ability of the biofilms to immobilize uranium correlated only partially with the biofilm biomass and thickness and depended greatly on the area of the biofilm exposed to the soluble contaminant. In contrast, uranium reduction depended on the expression of Geobacter conductive pili and, to a lesser extent, on the presence of the c cytochrome OmcZ in the biofilm matrix. The results support a model in which the electroactive biofilm matrix immobilizes and reduces the uranium in the top stratum. This mechanism prevents the permeation and mineralization of uranium in the cell envelope, thereby preserving essential cellular functions and enhancing the catalytic capacity of Geobacter cells to reduce uranium. Hence, the biofilms provide cells with a physically and chemically protected environment for the sustained immobilization and reduction of uranium that is of interest for the development of improved strategies for the in situ bioremediation of environments impacted by uranium contamination. PMID:25128347

  5. Anthropogenic carbon in the East Greenland Current

    NASA Astrophysics Data System (ADS)

    Jutterström, Sara; Jeansson, Emil

    2008-07-01

    Sections of dissolved inorganic anthropogenic carbon ( CTanthro) based on 2002 data in the East Greenland Current (EGC) are presented. The CTanthro has been estimated using a model based on optimum multiparameter analysis with predefined source water types. Values of CTanthro have been assigned to the source water types through age estimations based on the transit time distribution (TTD) technique. The validity of this approach is discussed and compared to other methods. The results indicated that the EGC had rather high levels of CTanthro in the whole water column, and the anthropogenic signal of the different source areas were detected along the southward transit. We estimated an annual transport of CTanthro with the Denmark Strait overflow ( σθ > 27.8 kg m -3) of ∼0.036 ± 0.005 Gt C y -1. The mean CTanthro concentration in this density range was ∼30 μmol kg -1. The main contribution was from Atlantic derived waters, the Polar Intermediate Water and the Greenland Sea Arctic Intermediate Water.

  6. PRODUCTION OF URANIUM

    DOEpatents

    Spedding, F.H.; Wilhelm, H.A.; Keller, W.H.

    1958-04-15

    The production of uranium metal by the reduction of uranium tetrafluoride is described. Massive uranium metal of high purily is produced by reacting uranium tetrafluoride with 2 to 20% stoichiometric excess of magnesium at a temperature sufficient to promote the reaction and then mantaining the reaction mass in a sealed vessel at temperature in the range of 1150 to 2000 d C, under a superatomospheric pressure of magnesium for a period of time sufficient 10 allow separation of liquid uranium and liquid magnesium fluoride into separate layers.

  7. URANIUM RECOVERY PROCESS

    DOEpatents

    Yeager, J.H.

    1958-08-12

    In the prior art processing of uranium ores, the ore is flrst digested with nitric acid and filtered, and the uranium values are then extracted tom the filtrate by contacting with an organic solvent. The insoluble residue has been processed separately in order to recover any uranium which it might contain. The improvement consists in contacting a slurry, composed of both solution and residue, with the organic solvent prior to filtration. Tbe result is that uranium values contained in the residue are extracted along with the uranium values contained th the solution in one step.

  8. PROCESS OF RECOVERING URANIUM

    DOEpatents

    Carter, J.M.; Larson, C.E.

    1958-10-01

    A process is presented for recovering uranium values from calutron deposits. The process consists in treating such deposits to produce an oxidlzed acidic solution containing uranium together with the following imparities: Cu, Fe, Cr, Ni, Mn, Zn. The uranium is recovered from such an impurity-bearing solution by adjusting the pH of the solution to the range 1.5 to 3.0 and then treating the solution with hydrogen peroxide. This results in the precipitation of uranium peroxide which is substantially free of the metal impurities in the solution. The peroxide precipitate is then separated from the solution, washed, and calcined to produce uranium trioxide.

  9. Uranium mineralization in southern Victoria Land, Antarctica

    SciTech Connect

    Dreschhoff, G.A.M.; Zeller, E.J.

    1986-01-01

    For the past 10 antarctic field seasons, an airborne gamma-ray spectrometric survey has been conducted over widely separated parts of the continent. Localized accumulations of both primary and secondary uranium minerals have been discovered at several localities scattered along the Transantarctic Mountains from the Scott Glacier to northern Victoria Land. A number of highly significant radiation anomalies have been discovered in the area between the Koettlitz Glacier and the Pyramid Trough. The occurrences consist of pegmatite vein complexes which contain an association of primary uranium and thorium minerals. Of still greater significance is the fact that abundant secondary uranium minerals were found in association with the primary deposits, and they indicate clearly that uranium is geochemically mobile under the conditions imposed by the arid polar climate that now exists in southern Victoria Land. Preliminary results of a uranium analysis performed by neutron activation indicate a concentration of 0.12% uranium in a composite sample from the two veins. Even higher levels of thorium are present. The nature of the primary uranium mineralization is currently under investigation. Preliminary results are discussed.

  10. Uranium in Canada: A billion dollar industry

    SciTech Connect

    Ruzicka, V. )

    1989-12-01

    In 1988, Canada maintained its position as the world's leading producer of uranium with an output of more than 12,400 MT of uranium in concentrates, worth $1.1 billion Canadian. As domestic requirements represent only 15% of current Canadian production, most of the output was exported. With current implementation of the Canada/US Free Trade Agreement, the US has become Canada's major uranium export customer. With a large share of the world's known uranium resources, Canada remains the focus of international uranium exploration activity. In 1988, the uranium exploration expenditures in Canada exceeded $58 million Canadian. The principal exploration targets were deposits associated with Proterozoic unconformities in Saskatchewan and Northwest Territories, particularly those in the Athabasca and Thelon basin regions of the Canadian Shield. Major attention was also paid to polymetallic deposits in which uranium is associated with precious metals, such as gold and platinum group elements. Conceptual genetic models for these deposit types represent useful tools to guide exploration.

  11. Method for converting uranium oxides to uranium metal

    DOEpatents

    Duerksen, Walter K.

    1988-01-01

    A process is described for converting scrap and waste uranium oxide to uranium metal. The uranium oxide is sequentially reduced with a suitable reducing agent to a mixture of uranium metal and oxide products. The uranium metal is then converted to uranium hydride and the uranium hydride-containing mixture is then cooled to a temperature less than -100.degree. C. in an inert liquid which renders the uranium hydride ferromagnetic. The uranium hydride is then magnetically separated from the cooled mixture. The separated uranium hydride is readily converted to uranium metal by heating in an inert atmosphere. This process is environmentally acceptable and eliminates the use of hydrogen fluoride as well as the explosive conditions encountered in the previously employed bomb-reduction processes utilized for converting uranium oxides to uranium metal.

  12. Metals other than uranium affected microbial community composition in a historical uranium-mining site.

    PubMed

    Sitte, Jana; Löffler, Sylvia; Burkhardt, Eva-Maria; Goldfarb, Katherine C; Büchel, Georg; Hazen, Terry C; Küsel, Kirsten

    2015-12-01

    To understand the links between the long-term impact of uranium and other metals on microbial community composition, ground- and surface water-influenced soils varying greatly in uranium and metal concentrations were investigated at the former uranium-mining district in Ronneburg, Germany. A soil-based 16S PhyloChip approach revealed 2358 bacterial and 35 archaeal operational taxonomic units (OTU) within diverse phylogenetic groups with higher OTU numbers than at other uranium-contaminated sites, e.g., at Oak Ridge. Iron- and sulfate-reducing bacteria (FeRB and SRB), which have the potential to attenuate uranium and other metals by the enzymatic and/or abiotic reduction of metal ions, were found at all sites. Although soil concentrations of solid-phase uranium were high, ranging from 5 to 1569 μg·g (dry weight) soil(-1), redundancy analysis (RDA) and forward selection indicated that neither total nor bio-available uranium concentrations contributed significantly to the observed OTU distribution. Instead, microbial community composition appeared to be influenced more by redox potential. Bacterial communities were also influenced by bio-available manganese and total cobalt and cadmium concentrations. Bio-available cadmium impacted FeRB distribution while bio-available manganese and copper as well as solid-phase zinc concentrations in the soil affected SRB composition. Archaeal communities were influenced by the bio-available lead as well as total zinc and cobalt concentrations. These results suggest that (i) microbial richness was not impacted by heavy metals and radionuclides and that (ii) redox potential and secondary metal contaminants had the strongest effect on microbial community composition, as opposed to uranium, the primary source of contamination.

  13. Semi-automated potentiometric titration method for uranium characterization.

    PubMed

    Cristiano, B F G; Delgado, J U; da Silva, J W S; de Barros, P D; de Araújo, R M S; Lopes, R T

    2012-07-01

    The manual version of the potentiometric titration method has been used for certification and characterization of uranium compounds. In order to reduce the analysis time and the influence of the analyst, a semi-automatic version of the method was developed in the Brazilian Nuclear Energy Commission. The method was applied with traceability assured by using a potassium dichromate primary standard. The combined standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization.

  14. Use of uranium isotopes as a temporal and spatial tracer of nuclear contamination in the environment.

    PubMed

    Tortorello, R; Widom, E; Renwick, W H

    2013-10-01

    The Fernald Feed Materials Production Center (FFMPC) was established in 1951 to process natural uranium (U) ore, enriched uranium (EU) and depleted uranium (DU). This study tests the utility of U isotopic ratios in sediment cores and lichens as indicators of the aerial extent, degree and timing of anthropogenic U contamination, using the FFMPC as a test case. An 80-cm-long sediment core was extracted from an impoundment located approximately 6.7 km southwest of the FFMPC. Elemental concentrations of thorium (2.7-6.2 μg g(-1)) and U (0.33-1.33 μg g(-1)) as well as major and minor U isotopes were analyzed in the core. The lack of measurable (137)Cs in the deepest sample as well as a natural (235)U/(238)U signature and no measurable (236)U, are consistent with pre-FFMPC activity. Anomalously elevated U with respect to Th concentrations occur in seven consecutive samples immediately above the base of the core (62-76 cm depth). Samples with elevated U concentrations also show variable (235)U/(238)U (0.00645-0.00748), and all contain measurable (236)U ((236)U/(238)U = 2.1 × 10(-6)-3.6 × 10(-5)). Correspondence between the known releases of U dust from the FFMPC through time and variations in sediment core U concentrations, (235)U/(238)U and (236)U/(238)U ratios provide evidence for distinct releases of both DU and EU. Furthermore, these relationships demonstrate that the sediment core serves as a robust archive of past environmental U contamination events. Samples in the upper 40 cm display natural (235)U/(238)U, but measurable (236)U/(238)U ((236)U/(238)U = 5.68 × 10(-6)-1.43 × 10(-5)), further indicating the continued presence of anthropogenic U in present-day sediment. Three local lichen samples were also analyzed, and all display either EU or DU signatures coupled with elevated (236)U/(238)U, recording airborne U contamination from the FFMPC.

  15. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  16. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  17. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  18. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  19. 31 CFR 540.317 - Uranium feed; natural uranium feed.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Uranium feed; natural uranium feed... (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed....

  20. Transfer of natural and anthropogenic radionuclides to ants, bryophytes and lichen in a semi-natural ecosystem.

    PubMed

    Dragović, Snezana; Howard, Brenda J; Caborn, Jane A; Barnett, Catherine L; Mihailović, Nevena

    2010-07-01

    Few data are available to quantify the transfer of both natural and anthropogenic radionuclides to detritivorous invertebrates to facilitate estimation of the internal dose to such biota in models used to assess radiation exposure. To enhance the available data, activity concentrations of (137)Cs, (40)K, (90)Sr, (239 + 240)Pu, (241)Am, (235)U and (238)U were measured in ants (Formicidae) and corresponding undisturbed soil collected from the Zlatibor mountain in Serbia and ant/soil concentration ratios (CR) calculated. The (241)Am concentration ratios for ants were fourfold higher than those calculated for ants in a previous study whereas they are similar to the more numerous data previously reported for a range of detritivorous invertebrates in other studies. CR values for (137)Cs in ants were similar to the few other reported values and slightly lower than those for a range of detritivorous invertebrates. Those for (239 + 240)Pu were slightly higher than those for ants in two other studies but they were close to upper limit of a range of data reported for detritivorous invertebrates. All the CR values will be included in a future revision of the ERICA Tool database and will particularly improve the information available for uranium.

  1. Uranium and cesium accumulation in bean (Phaseolus vulgaris L. var. vulgaris) and its potential for uranium rhizofiltration.

    PubMed

    Yang, Minjune; Jawitz, James W; Lee, Minhee

    2015-02-01

    Laboratory scale rhizofiltration experiments were performed to investigate uranium and cesium accumulation in bean (Phaseolus vulgaris L. var. vulgaris) and its potential for treatment of uranium contaminated groundwater. During 72 h of rhizofiltration, the roots of the bean accumulated uranium and cesium to concentrations 317-1019 times above the initial concentrations, which ranged from 100 to 700 μg l(-1) in artificially contaminated solutions. When the pH of the solution was adjusted to 3, the ability to accumulate uranium was 1.6 times higher than it was for solutions of pH 7 and pH 9. With an initial uranium concentration of 240 μg l(-1) in genuine groundwater at pH 5, the bean reduced the uranium concentration by 90.2% (to 23.6 μg l(-1)) within 12 h and by 98.9% (to 2.8 μg l(-1)) within 72 h. A laboratory scale continuous clean-up system reduced uranium concentrations from 240 μg l(-1) to below 10 μg l(-1) in 56 h; the whole uranium concentration in the bean roots during system operation was more than 2600 μg g(-1) on a dry weight basis. Using SEM and EDS analyses, the uranium removal in solution at pH 7 was determined based on adsorption and precipitation on the root surface in the form of insoluble uranium compounds. The present results demonstrate that the rhizofiltration technique using beans efficiently removes uranium and cesium from groundwater as an eco-friendly and cost-effective method.

  2. Technical Basis for Assessing Uranium Bioremediation Performance

    SciTech Connect

    PE Long; SB Yabusaki; PD Meyer; CJ Murray; AL N’Guessan

    2008-04-01

    In situ bioremediation of uranium holds significant promise for effective stabilization of U(VI) from groundwater at reduced cost compared to conventional pump and treat. This promise is unlikely to be realized unless researchers and practitioners successfully predict and demonstrate the long-term effectiveness of uranium bioremediation protocols. Field research to date has focused on both proof of principle and a mechanistic level of understanding. Current practice typically involves an engineering approach using proprietary amendments that focuses mainly on monitoring U(VI) concentration for a limited time period. Given the complexity of uranium biogeochemistry and uranium secondary minerals, and the lack of documented case studies, a systematic monitoring approach using multiple performance indicators is needed. This document provides an overview of uranium bioremediation, summarizes design considerations, and identifies and prioritizes field performance indicators for the application of uranium bioremediation. The performance indicators provided as part of this document are based on current biogeochemical understanding of uranium and will enable practitioners to monitor the performance of their system and make a strong case to clients, regulators, and the public that the future performance of the system can be assured and changes in performance addressed as needed. The performance indicators established by this document and the information gained by using these indicators do add to the cost of uranium bioremediation. However, they are vital to the long-term success of the application of uranium bioremediation and provide a significant assurance that regulatory goals will be met. The document also emphasizes the need for systematic development of key information from bench scale tests and pilot scales tests prior to full-scale implementation.

  3. Uranium dynamics and developmental sensitivity in rat kidney.

    PubMed

    Homma-Takeda, Shino; Kokubo, Toshiaki; Terada, Yasuko; Suzuki, Kyoko; Ueno, Shunji; Hayao, Tatsuo; Inoue, Tatsuya; Kitahara, Keisuke; Blyth, Benjamin J; Nishimura, Mayumi; Shimada, Yoshiya

    2013-07-01

    Renal toxicity is the principal health concern after uranium exposure. Children are particularly vulnerable to uranium exposure; with contact with depleted uranium in war zones or groundwater contamination the most likely exposure scenarios. To investigate renal sensitivity to uranium exposure during development, we examined uranium distribution and uranium-induced apoptosis in the kidneys of neonate (7-day-old), prepubertal (25-day-old) and adult (70-day-old) male Wistar rats. Mean renal uranium concentrations increased with both age-at-exposure and exposure level after subcutaneous administration of uranium acetate (UA) (0.1-2 mg kg(-1) body weight). Although less of the injected uranium was deposited in the kidneys of the two younger rat groups, the proportion of the peak uranium content remaining in the kidneys after 2 weeks declined with age-at-exposure, suggesting reduced clearance in younger animals. In situ high-energy synchrotron radiation X-ray fluorescence analysis revealed site-specific accumulation of uranium in the S3 segment of the proximal tubules, distributed in the inner cortex and outer stripe of the outer medulla. Apoptosis and cell loss in the proximal tubules increased with age-at-exposure to 0.5 mg kg(-1) UA. Surprisingly, prepubertal rats were uniquely sensitive to uranium-induced lethality from the higher exposure levels. Observations of increased apoptosis in generating/re-generating tubules particularly in prepubertal rats could help to explain their high mortality rate. Together, our findings suggest that age-at-exposure and exposure level are important parameters for uranium toxicity; uranium tends to persist in developing kidneys after low-level exposures, although renal toxicity is more pronounced in adults.

  4. Anthropogenic enhancement of Egypt's Mediterranean fishery

    PubMed Central

    Oczkowski, Autumn J.; Nixon, Scott W.; Granger, Stephen L.; El-Sayed, Abdel-Fattah M.; McKinney, Richard A.

    2009-01-01

    The highly productive coastal Mediterranean fishery off the Nile River delta collapsed after the completion of the Aswan High Dam in 1965. But the fishery has been recovering dramatically since the mid-1980s, coincident with large increases in fertilizer application and sewage discharge in Egypt. We use stable isotopes of nitrogen (δ15N) to demonstrate that 60%–100% of the current fishery production may be from primary production stimulated by nutrients from fertilizer and sewage runoff. Although the establishment of the dam put Egypt in an ideal position to observe the impact of rapid increases in nutrient loading on coastal productivity in an extremely oligotrophic sea, the Egyptian situation is not unique. Such anthropogenically enhanced fisheries also may occur along the northern rim of the Mediterranean and offshore of some rapidly developing tropical countries, where nutrient concentrations in the coastal waters were previously very low. PMID:19164510

  5. Isotopic fractionation of uranium in sandstone

    USGS Publications Warehouse

    Rosholt, J.N.; Shields, W.R.; Garner, E.L.

    1963-01-01

    Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.

  6. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  7. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  8. Car Catalysts Impact on Anthropogenic Osmium Budget

    NASA Astrophysics Data System (ADS)

    Poirier, A.; Gariepy, C.

    2004-05-01

    A few sources of anthropogenic osmium have been identified that clearly contribute to the observed increase in unradiogenic osmium in recent urban sediments (a major one being biomedical use of OsO4 as a lipid stain used to enhance cell structures for optical and electron microscopy (1,2,3,4)). Previous studies suggested the possibility that automobile catalytic converters might also contribute to this Os pollution, even though this metal is not directly employed in car catalysts (1,4). The importance of this potential source has never been quantitatively tested. Here, we present results for the Os isotope analysis of 4 new catalytic converters. The unradiogenic 187Os/188Os composition of all catalytic converters is similar to typical platinum group elements ore (5). The measured Os concentrations are in the pg/g range (6-228 pg/g). The physical conditions in catalysts (oxidising environment and 300 \\deg C) are effective in promoting the oxidation of osmium to its gaseous form. We therefore expect that osmium volatility plays an important role in releasing Os from the catalysts. Based on measured concentrations, we estimate that car catalysts could be responsible for up to several picograms of anthropogenic osmium deposited per square meter in urban areas every year. Our results strengthen the idea that automobile catalytic converters might be a significant source of Os pollution. 1.Ravizza, G. E. and Bothner, M. H. (1996) Geochimica et Cosmochimica Acta, 60; 15, 2753-2763. 2.Smith, I. C., Carson, B. L., and Ferguson T.L. (1974) Environmental Health Perspectives, 8, 201-213. 3.Esser, B. K. and Turekian, K. K. (1993) Environmental Science and Technology, 27; 13, 2719-2724. 4.Rauch S., Hemond H.F., and Peucker-Ehrenbrink, B. (2004) Environmental Science and Technology, 38, 396-402. 5.McCandless, T. and Ruiz, J. (1991) Geology, 19, 1225-1228.

  9. Treatment of effluents from uranium oxide production.

    PubMed

    Ladeira, A C Q; Gonçalves, J S; Morais, C A

    2011-01-01

    The nuclear fuel cycle comprises a series of industrial processes which involve the production of electricity from uranium in nuclear power reactors. In Brazil the conversion of uranium hexafluoride (UF6) into uranium dioxide (UO2) takes place in Resende (RJ) at the Nuclear Fuel Factory (FCN). The process generates liquid effluents with significant concentrations of uranium, which might be treated before being discharged into the environment. This study investigates the recovery of uranium from three distinct liquid effluents: one with a high carbonate content and the other with an elevated fluoride concentration. This paper also presents a study on carbonate removal from an effluent that consists of a water-methanol solution generated during the filtration of the yellow cake (ammonium uranyl tricarbonate). The results showed that: (1) the uranium from the carbonated solution can be recovered through the ion exchange technique using the strong base anionic resin IRA 910-U, as the carbonate has been removed as CO2 after heating; (2) the most suitable technique to recover uranium from the fluoride solution is its precipitation as (NH4)2UO4F2 (ammonium fluorouranate peroxide), (3) the solution free of carbonate can be added to the fluoride solution and the uranium from the final solution can be recovered by precipitation as ammonium fluorouranate peroxide as well; (4) the carbonate from the water-methanol solution can be recovered as calcium carbonate through the addition of calcium chloride, or it can be recovered as ammonium sulphate through the addition of sulphuric acid. The ammonium sulphate product can be used as a fertilizer.

  10. Ecology of estuaries: Anthropogenic effects

    SciTech Connect

    Kennish, M.J.

    1992-01-01

    Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; radionuclides) biological impacts; waste management; impacts of power plants; dredging and spoil disposal; case studies, primarily Chesapeake Bay. The book serves as a text and as a reference.

  11. Fate of Uranium during Sodium Aluminosilicate Formation under Waste Tank Conditions

    SciTech Connect

    Wilmarth, B

    2005-06-22

    Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted. Lastly, analysis of the uranium speciation in a Tank 49H set of samples showed the uranium to be soluble. Analysis of the solution composition and subsequent use of the Hobb's uranium solubility model indicated a uranium solubility limit of 32 mg/L. The measured value of uranium in the Tank 49H matched the model prediction.

  12. Pollution of the stream waters and sediments associated with the Crucea uranium mine (East Carpathians, Romania)

    NASA Astrophysics Data System (ADS)

    Petrescu, L.; Bilal, E.; Iatan, E. L.

    2009-04-01

    Uranium and thorium are omnipresent in our environment. Various anthropogenic activities involving the processing or use of materials rich in uranium may modify the natural abundance of uranium in water. The study is related to uranium mineralization located within Crucea ore deposit, in the East Carpathians, Romania. The Crucea uranium ore deposit is located in the eastern part of the Bistrita Mountains (40 Km southeast of the town of Vatra Dornei) in the headwaters of Crucea, Lesu and Livezi valleys. At present, this is the largest uranium mine in the country. In the past, the mining area covered 18 km2, but was gradually overtaken by logging activities. The exploration and mining facilities include thirty-two galleries, situated between 780 and 1040 m above sea level. Radioactive waste resulted from mining are disposed next to the mining facilities. The waste rock was disposed in piles of variable size that are spread over an area of 364,000 m2. Older dumps (18) have been already naturally reclaimed by forest vegetation. The vegetation cover played an important role in stabilizing the waste dump cover and in slowing down the uranium migration processes. A number of 46 water samples were taken in order to evaluate the impact of ore deposit (including its exploitation process) on the chemical composition of waters down to the exploitation galleries. The sediment samples were collected at 16 sampling points from the bottom of the studied stream waters. ICP-OES, XRF and IC methods was used to evaluate the impact of uranium mine dumps on the surface waters from Crucea region. According to the analytical data the stream waters showed a Ca - carbonate character. In relation to salinity, the pH and the anion NO3-, CO32-and SO42- contents display generally non-linear relationships with chloride. Uranium is the most significant trace element in the river waters nearby the waste rock dumps, sometimes reaching levels up to 1-mgṡL-1, well in excess of the Romanian

  13. Gastrointestinal absorption of uranium compounds--a review.

    PubMed

    Konietzka, Rainer

    2015-02-01

    Uranium occurs naturally in soil and rocks, and therefore where it is present in water-soluble form it also occurs naturally in groundwater as well as in drinking water obtained from groundwater. Animal studies suggest that the toxicity of uranium is mainly due to its damage to kidney tubular cells following exposure to soluble uranium compounds. The assessments of the absorption of uranium via the gastrointestinal tract vary, and this has consequences for regulation, in particular the derivation of e.g. drinking water limit values. Absorption rates vary according to the nature and solubility of the compound in which uranium is presented to the test animals and depending on the animal species used in the test. No differences for sex have been observed for absorption in either animals or humans. However, human biomonitoring data do show that boys excrete significantly more uranium than girls. In animal studies neonates took up more uranium than adults or older children. Nutritional status, and in particular the iron content of the diet, have a marked influence on absorption, and higher uranium levels in food intake also appear to increase the absorption rate. If the pointers to an absorption mechanism competing with iron are correct, these mechanisms could also explain the relatively high concentration and chemical toxicity of uranium in the kidneys. It is here (and in the duodenum) that divalent metal transporter 1 (DMT1), which is primarily responsible for the passage of iron (or uranium?) through the cell membranes, is most strongly expressed.

  14. Assessing the environmental availability of uranium in soils and sediments

    SciTech Connect

    Amonette, J.E.; Holdren, G.R. Jr.; Krupa, K.M.; Lindenmeier, C.W.

    1994-06-01

    Soils and sediments contaminated with uranium pose certain environmental and ecological risks. At low to moderate levels of contamination, the magnitude of these risks depends not only on the absolute concentrations of uranium in the material but also on the availability of the uranium to drinking water supplies, plants, or higher organisms. Rational approaches for regulating the clean-up of sites contaminated with uranium, therefore, should consider the value of assessing the environmental availability of uranium at the site before making decisions regarding remediation. The purpose of this work is to review existing approaches and procedures to determine their potential applicability for assessing the environmental availability of uranium in bulk soils or sediments. In addition to making the recommendations regarding methodology, the authors have tabulated data from the literature on the aqueous complexes of uranium and major uranium minerals, examined the possibility of predicting environmental availability of uranium based on thermodynamic solubility data, and compiled a representative list of analytical laboratories capable of performing environmental analyses of uranium in soils and sediments.

  15. Anthropogenic radionuclides in the environment

    SciTech Connect

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  16. Uranium in US surface, ground, and domestic waters

    SciTech Connect

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium concentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  17. Uranium in US surface, ground, and domestic waters

    SciTech Connect

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters, comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium concentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  18. Uranium provinces of North America; their definition, distribution, and models

    USGS Publications Warehouse

    Finch, Warren Irvin

    1996-01-01

    Uranium resources in North America are principally in unconformity-related, quartz-pebble conglomerate, sandstone, volcanic, and phosphorite types of uranium deposits. Most are concentrated in separate, well-defined metallogenic provinces. Proterozoic quartz-pebble conglomerate and unconformity-related deposits are, respectively, in the Blind River?Elliot Lake (BRELUP) and the Athabasca Basin (ABUP) Uranium Provinces in Canada. Sandstone uranium deposits are of two principal subtypes, tabular and roll-front. Tabular sandstone uranium deposits are mainly in upper Paleozoic and Mesozoic rocks in the Colorado Plateau Uranium Province (CPUP). Roll-front sandstone uranium deposits are in Tertiary rocks of the Rocky Mountain and Intermontane Basins Uranium Province (RMIBUP), and in a narrow belt of Tertiary rocks that form the Gulf Coastal Uranium Province (GCUP) in south Texas and adjacent Mexico. Volcanic uranium deposits are concentrated in the Basin and Range Uranium Province (BRUP) stretching from the McDermitt caldera at the Oregon-Nevada border through the Marysvale district of Utah and Date Creek Basin in Arizona and south into the Sierra de Pe?a Blanca District, Chihuahua, Mexico. Uraniferous phosphorite occurs in Tertiary sediments in Florida, Georgia, and North and South Carolina and in the Lower Permian Phosphoria Formation in Idaho and adjacent States, but only in Florida has economic recovery been successful. The Florida Phosphorite Uranium Province (FPUP) has yielded large quantities of uranium as a byproduct of the production of phosphoric acid fertilizer. Economically recoverable quantities of copper, gold, molybdenum, nickel, silver, thorium, and vanadium occur with the uranium deposits in some provinces. Many major epochs of uranium mineralization occurred in North America. In the BRELUP, uranium minerals were concentrated in placers during the Early Proterozoic (2,500?2,250 Ma). In the ABUP, the unconformity-related deposits were most likely formed

  19. Preparation of uranium compounds

    DOEpatents

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  20. Metals fact sheet - uranium

    SciTech Connect

    1996-04-01

    About 147 million pounds of this radioactive element are consumed annually by the worldwide nuclear power and weapons industries, as well as in the manufacture of ceramics and metal products. The heaviest naturally occurring element, uranium is typically found in intrusive granites, igneous and metamorphic veins, tabular sedimentary deposits, and unconformity-related structures. This article discusses the geology, exploitation, market, and applications of uranium and uranium ores.

  1. Process for continuous production of metallic uranium and uranium alloys

    DOEpatents

    Hayden, Jr., Howard W.; Horton, James A.; Elliott, Guy R. B.

    1995-01-01

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO.sub.3), or any other substantially stable uranium oxide, to form the uranium dioxide (UO.sub.2). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl.sub.4), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation.

  2. Process for continuous production of metallic uranium and uranium alloys

    DOEpatents

    Hayden, H.W. Jr.; Horton, J.A.; Elliott, G.R.B.

    1995-06-06

    A method is described for forming metallic uranium, or a uranium alloy, from uranium oxide in a manner which substantially eliminates the formation of uranium-containing wastes. A source of uranium dioxide is first provided, for example, by reducing uranium trioxide (UO{sub 3}), or any other substantially stable uranium oxide, to form the uranium dioxide (UO{sub 2}). This uranium dioxide is then chlorinated to form uranium tetrachloride (UCl{sub 4}), and the uranium tetrachloride is then reduced to metallic uranium by reacting the uranium chloride with a metal which will form the chloride of the metal. This last step may be carried out in the presence of another metal capable of forming one or more alloys with metallic uranium to thereby lower the melting point of the reduced uranium product. The metal chloride formed during the uranium tetrachloride reduction step may then be reduced in an electrolysis cell to recover and recycle the metal back to the uranium tetrachloride reduction operation and the chlorine gas back to the uranium dioxide chlorination operation. 4 figs.

  3. Uranium in hot water tanks: a source of TENORM.

    PubMed

    DeVol, T A; Woodruff, R L

    2004-12-01

    Uranium deposits were detected inside hot water tanks using gamma-ray spectroscopic techniques and corroborated by the difference in the uranium concentration of the groundwater entering and leaving the hot water tanks. In-situ gamma-ray spectroscopy was performed using a transportable high-purity germanium (HPGe) gamma-ray spectrometer to estimate the mass of uranium in the hot water tanks. Gamma-ray spectroscopic analyses of hot water tanks in four residences with groundwater uranium concentration between 732 and 7,667 mug L revealed an estimated 3.5 to 69 g of uranium in each hot water tank. The uranium deposit within the tanks was indicated by the 143.8, 163.4, and 185.7 keV gamma rays of U and confirmed with the 63.3, 92.3, and 92.8 keV gamma rays of Th as well as the 1,001 keV peak of Pa. An average decrease in uranium concentration of 23% was observed in the groundwater that passed through the hot water tanks. Additionally, once "uranium free" water entered the hot water tanks, the uranium deposits within the tanks resulted in an increase in the uranium concentration in the effluent water. The groundwater had an alkalinity in the range of 46-96 mg L as CaCO3 and a pH range of 7.3-8.1. The accumulation of uranium in these hot water tanks results in them being classified as technologically enhanced naturally occurring radioactive materials (TENORM).

  4. Recovery of uranium from seawater by immobilized tannin

    SciTech Connect

    Sakaguchi, T.; Nakajima, A.

    1987-06-01

    Tannin compounds having multiple adjacent hydroxy groups have an extremely high affinity for uranium. To prevent the leaching of tannins into water and to improve the adsorbing characteristics of these compounds, the authors tried to immobilize tannins. The immobilized tannin has the most favorable features for uranium recovery; high selective adsorption ability to uranium, rapid adsorption rate, and applicability in both column and batch systems. The immobilized tannin can recover uranium from natural seawater with high efficiency. About 2530 ..mu..g uranium is adsorbed per gram of this adsorbent within 22 h. Depending on the concentration in seawater, an enrichment of up to 766,000-fold within the adsorbent is possible. Almost all uranium adsorbed is easily desorbed with a very dilute acid. Thus, the immobilized tannin can be used repeatedly in the adsorption-desorption process.

  5. Spatial and temporal variation of uranium in a shallow weathered rock aquifer in southern India

    NASA Astrophysics Data System (ADS)

    Brindha, K.; Elango, L.; Nair, R. N.

    2011-10-01

    Uranium occurs naturally in groundwater and surface water. The objective of this study is to understand the causes for the occurrence of uranium and its spatio-temporal variation in groundwater in a part of Nalgonda district, Andhra Pradesh, south India. Uranium deposits occur in the southeastern part of this area. Groundwater samples were collected from 44 wells every two months from March 2008 to January 2009. The samples were analyzed for pH, ORP and uranium concentration. The uranium concentration in groundwater varies from 0.2 ppb to a maximum of 68 ppb with a mean of 18.5 ppb. About 21.6% of the samples were above the drinking water limit of 30 ppb set by USEPA. The uranium concentration varied with fluctuation in groundwater level, pH and ORP. Uranium concentration in groundwater changes depending on lithology, degree of weathering and rainfall recharge.

  6. MODELING THE EFFECT OF CHLORINE EMISSIONS ON ATMOSPHERIC OZONE AND SECONDARY ORGANIC AEROSOL CONCENTRATIONS ACROSS THE UNITED STATES

    EPA Science Inventory

    This paper presents the modeled effects of natural and anthropogenic chlorine emissions on the atmospheric concentrations of ozone and secondary organic aerosol across the United States. The model calculations include anthropogenic molecular chlorine emissions, anthropogenic hypo...

  7. Uranium in groundwater--Fertilizers versus geogenic sources.

    PubMed

    Liesch, Tanja; Hinrichsen, Sören; Goldscheider, Nico

    2015-12-01

    Due to its radiological and toxicological properties even at low concentration levels, uranium is increasingly recognized as relevant contaminant in drinking water from aquifers. Uranium originates from different sources, including natural or geogenic, mining and industrial activities, and fertilizers in agriculture. The goal of this study was to obtain insights into the origin of uranium in groundwater while differentiating between geogenic sources and fertilizers. A literature review concerning the sources and geochemical processes affecting the occurrence and distribution of uranium in the lithosphere, pedosphere and hydrosphere provided the background for the evaluation of data on uranium in groundwater at regional scale. The state of Baden-Württemberg, Germany, was selected for this study, because of its hydrogeological and land-use diversity, and for reasons of data availability. Uranium and other parameters from N=1935 groundwater monitoring sites were analyzed statistically and geospatially. Results show that (i) 1.6% of all water samples exceed the German legal limit for drinking water (10 μg/L); (ii) The range and spatial distribution of uranium and occasional peak values seem to be related to geogenic sources; (iii) There is a clear relation between agricultural land-use and low-level uranium concentrations, indicating that fertilizers generate a measurable but low background of uranium in groundwater.

  8. Forensic analysis of uranium

    SciTech Connect

    Stoyer, N.J.; Moody, K.J.

    1996-10-01

    As more and more offers for illicit {open_quotes}Black Market{close_quotes} radioactive materials are found, the forensic information contained within the radioactive material itself becomes more important. Many {open_quotes}Black Market{close_quotes} offers are for uranium in various forms and enrichments. Although most are scams, some countries have actually interdicted enriched uranium. We will discuss the forensic information that can be obtained from materials containing uranium along with examples of data that has been determined from analysis of uranium samples obtained from legitimate sources.

  9. METHOD OF ROLLING URANIUM

    DOEpatents

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  10. Uranium Dispersion & Dosimetry Model.

    SciTech Connect

    MICHAEL,; MOMENI, H.

    2002-03-22

    The Uranium Dispersion and Dosimetry (UDAD) program provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility such as a uranium mine or mill. Only transport through the air is considered. Exposure results from inhalation, external irradiation from airborne and ground-deposited activity, and ingestion of foodstuffs. Individual dose commitments, population dose commitments, and environmental dose commitments are computed. The program was developed for application to uranium mining and milling; however, it may be applied to dispersion of any other pollutant.

  11. Uranium Dispersion & Dosimetry Model.

    2002-03-22

    The Uranium Dispersion and Dosimetry (UDAD) program provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility such as a uranium mine or mill. Only transport through the air is considered. Exposure results from inhalation, external irradiation from airborne and ground-deposited activity, and ingestion of foodstuffs. Individual dose commitments, population dose commitments, and environmental dose commitments are computed. The program was developed for applicationmore » to uranium mining and milling; however, it may be applied to dispersion of any other pollutant.« less

  12. URANIUM RECOVERY PROCESS

    DOEpatents

    Kaufman, D.

    1958-04-15

    A process of recovering uranium from very low-grade ore residues is described. These low-grade uraniumcontaining hydroxide precipitates, which also contain hydrated silica and iron and aluminum hydroxides, are subjected to multiple leachings with aqueous solutions of sodium carbonate at a pH of at least 9. This leaching serves to selectively extract the uranium from the precipitate, but to leave the greater part of the silica, iron, and aluminum with the residue. The uranium is then separated from the leach liquor by the addition of an acid in sufficient amount to destroy the carbonate followed by the addition of ammonia to precipitate uranium as ammonium diuranate.

  13. PRODUCTION OF URANIUM

    DOEpatents

    Ruehle, A.E.; Stevenson, J.W.

    1957-11-12

    An improved process is described for the magnesium reduction of UF/sub 4/ to produce uranium metal. In the past, there have been undesirable premature reactions between the Mg and the bomb liner or the UF/sub 4/ before the actual ignition of the bomb reaction. Since these premature reactions impair the yield of uranium metal, they have been inhibited by forming a protective film upon the particles of Mg by reacting it with hydrated uranium tetrafluoride, sodium bifluoride, uranyl fluoride, or uranium trioxide. This may be accomplished by adding about 0.5 to 2% of the additive to the bomb charge.

  14. COATING URANIUM FROM CARBONYLS

    DOEpatents

    Gurinsky, D.H.; Storrs, S.S.

    1959-07-14

    Methods are described for making adherent corrosion resistant coatings on uranium metal. According to the invention, the uranium metal is heated in the presence of an organometallic compound such as the carbonyls of nickel, molybdenum, chromium, niobium, and tungsten at a temperature sufficient to decompose the metal carbonyl and dry plate the resultant free metal on the surface of the uranium metal body. The metal coated body is then further heated at a higher temperature to thermally diffuse the coating metal within the uranium bcdy.

  15. Elemental bio-imaging of thorium, uranium, and plutonium in tissues from occupationally exposed former nuclear workers.

    PubMed

    Hare, Dominic; Tolmachev, Sergei; James, Anthony; Bishop, David; Austin, Christine; Fryer, Fred; Doble, Philip

    2010-04-15

    Internal exposure from naturally occurring radionuclides (including the inhaled long-lived actinides (232)Th and (238)U) is a component of the ubiquitous background radiation dose (National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States; NCRP Report No. 160; NCRP: Bethesda, MD, 2009). It is of interest to compare the concentration distribution of these natural alpha-emitters in the lungs and respiratory lymph nodes with those resulting from occupational exposure, including exposure to anthropogenic plutonium and depleted and enriched uranium. This study examines the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantifying and visualizing the mass distribution of uranium and thorium isotopes from both occupational and natural background exposure in human respiratory tissues and, for the first time, extends this application to the direct imaging of plutonium isotopes. Sections of lymphatic and lung tissues taken from deceased former nuclear workers with a known history of occupational exposure to specific actinide elements (uranium, plutonium, or americium) were analyzed by LA-ICPMS. Using a previously developed LA-ICPMS protocol for elemental bio-imaging of trace elements in human tissue and a new software tool, we generated images of thorium ((232)Th), uranium ((235)U and (238)U), and plutonium ((239)Pu and (240)Pu) mass distributions in sections of tissue. We used a laboratory-produced matrix-matched standard to quantify the (232)Th, (235)U, and (238)U concentrations. The plutonium isotopes (239)Pu and (240)Pu were detected by LA-ICPMS in 65 mum diameter localized regions of both a paratracheal lymph node and a sample of lung tissue from a person who was occupationally exposed to refractory plutonium (plutonium dioxide). The average (overall) (239)Pu concentration in the lymph node was 39.2 ng/g, measured by high purity germanium (HPGe) gamma

  16. Resilience of southwestern Amazon forests to anthropogenic edge effects.

    PubMed

    Phillips, Oliver L; Rose, Sam; Mendoza, Abel Monteagudo; Vargas, Percy Núñez

    2006-12-01

    Anthropogenic edge effects can compromise the conservation value of mature tropical forests. To date most edge-effect research in Amazonia has concentrated on forests in relatively seasonal locations or with poor soils in the east of the basin. We present the first evaluation from the relatively richer soils of far western Amazonia on the extent to which mature forest biomass, diversity, and composition are affected by edges. In a southwestern Amazonian landscape we surveyed woody plant diversity, species composition, and biomass in 88x0.1 ha samples of unflooded forest that spanned a wide range in soil properties and included samples as close as 50 m and as distant as >10 km from anthropogenic edges. We applied Mantel tests, multiple regression on distance matrices, and other multivariate techniques to identify anthropogenic effects before and after accounting for soil factors and spatial autocorrelation. The distance to the nearest edge, access point, and the geographical center of the nearest community ("anthropogenic-distance effects") all had no detectable effect on tree biomass or species diversity. Anthropogenic-distance effects on tree species composition were also below the limits of detection and were negligible in comparison with natural environmental and spatial factors. Analysis of the data set's capacity to detect anthropogenic effects confirmed that the forests were not severely affected by edges, although because our study had few plots within 100 m of forest edges, our confidence in patterns in the immediate vicinity of edges is limited. It therefore appears that the conservation value of most "edge" forests in this region has not yet been compromised substantially. We caution that because this is one case study it should not be overinterpreted, but one explanation for our findings may be that western Amazonian tree species are naturally faster growing and more disturbance adapted than those farther east.

  17. Sources of anthropogenic radionuclides in the environment: a review.

    PubMed

    Hu, Qin-Hong; Weng, Jian-Qing; Wang, Jin-Sheng

    2010-06-01

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview on sources of anthropogenic radionuclides in the environment, as well as a brief discussion of salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current developments that have lead, or could potentially contribute, to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) uranium mining and milling; (5) commercial fuel reprocessing; (6) geological repository of high-level nuclear wastes that include radionuclides might be released in the future, and (7) nuclear accidents. Then, we briefly summarize the inventory of radionuclides (99)Tc and (129)I, as well as geochemical behavior for radionuclides (99)Tc, (129)I, and (237)Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment; biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides. PMID:18819734

  18. Influence of acidic and alkaline waste solution properties on uranium migration in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Szecsody, Jim E.; Truex, Mike J.; Qafoku, Nikolla P.; Wellman, Dawn M.; Resch, Tom; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments have significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100 s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2 +, Mg2 +) and phosphate and a slow (100 s of hours) increase in silica, Al3 +, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10 s to 100 s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in not only uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  19. Influence of acidic and alkaline waste solution properties on uranium migration in subsurface sediments.

    PubMed

    Szecsody, Jim E; Truex, Mike J; Qafoku, Nikolla P; Wellman, Dawn M; Resch, Tom; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments have significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100 s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH2) resulted in a rapid (<10 h) increase in aqueous carbonate (with Ca(2+), Mg(2+)) and phosphate and a slow (100 s of hours) increase in silica, Al(3+), and K(+), likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH13) resulted in a rapid (<10h) increase in carbonate, followed by a slow (10 s to 100 s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in not only uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  20. Influence of acidic and alkaline waste solution properties on uranium migration in subsurface sediments.

    PubMed

    Szecsody, Jim E; Truex, Mike J; Qafoku, Nikolla P; Wellman, Dawn M; Resch, Tom; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments have significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100 s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH2) resulted in a rapid (<10 h) increase in aqueous carbonate (with Ca(2+), Mg(2+)) and phosphate and a slow (100 s of hours) increase in silica, Al(3+), and K(+), likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH13) resulted in a rapid (<10h) increase in carbonate, followed by a slow (10 s to 100 s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in not only uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity. PMID:23851265

  1. Influence of Acidic and Alkaline Waste Solution Properties on Uranium Migration in Subsurface Sediments

    SciTech Connect

    Szecsody, James E.; Truex, Michael J.; Qafoku, Nikolla; Wellman, Dawn M.; Resch, Charles T.; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments has significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2+, Mg2+) and phosphate and a slow (100s of hours) increase in silica, Al3+, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10s to 100s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  2. URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO

    SciTech Connect

    S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

    2006-04-01

    Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (< 10 m/yr). Field tests, well productivity, and uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit.

  3. Chemical aspects of uranium behavior in soils: A review

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.

    2011-08-01

    Uranium has varying degrees of oxidation (+4 and +6) and is responsive to changes in the redox potential of the environment. It is deposited at the reduction barrier with the participation of biota and at the sorption barrier under oxidative conditions. Iron (hydr)oxides are the strongest sorbents of uranium. Uranium, being an element of medium biological absorption, can accumulate (relative to thorium) in the humus horizons of some soils. The high content of uranium in uncontaminated soils is most frequently inherited from the parent rocks in the regions of positive U anomalies: in the soils developed on oil shales and in the marginal zone of bogs at the reduction barrier. The development of nuclear and coal-fired power engineering resulted in the environmental contamination with uranium. The immobilization of anthropogenic uranium at artificial geochemical barriers is based on two preconditions: the stimulation of on-site metal-reducing bacteria or the introduction of strong mineral reducers, e.g., Fe at low degrees of oxidation.

  4. URANIUM LEACHING AND RECOVERY PROCESS

    DOEpatents

    McClaine, L.A.

    1959-08-18

    A process is described for recovering uranium from carbonate leach solutions by precipitating uranium as a mixed oxidation state compound. Uranium is recovered by adding a quadrivalent uranium carbon;te solution to the carbonate solution, adjusting the pH to 13 or greater, and precipitating the uranium as a filterable mixed oxidation state compound. In the event vanadium occurs with the uranium, the vanadium is unaffected by the uranium precipitation step and remains in the carbonate solution. The uranium-free solution is electrolyzed in the cathode compartment of a mercury cathode diaphragm cell to reduce and precipitate the vanadium.

  5. [Biosorption of Radionuclide Uranium by Deinococcus radiodurans].

    PubMed

    Yang, Jie; Dong, Fa-qin; Dai, Qun-wei; Liu, Ming-xue; Nie, Xiao-qin; Zhang, Dong; Ma, Jia-lin; Zhou, Xian

    2015-04-01

    As a biological adsorbent, Living Deinococcus radiodurans was used for removing radionuclide uranium in the aqueous solution. The effect factors on biosorption of radionuclide uranium were researched in the present paper, including solution pH values and initial uranium concentration. Meanwhile, the biosorption mechanism was researched by the method of FTIR and SEM/EDS. The results show that the optimum conditions for biosorption are as follows: pH = 5, co = 100 mg · L(-1) and the maximum biosorption capacity is up to 240 mgU · g(-1). According to the SEM results and EDXS analysis, it is indicated that the cell surface is attached by lots of sheet uranium crystals, and the main biosorpiton way of uranium is the ion exchange or surface complexation. Comparing FTIR spectra and FTIR fitting spectra before and after biosorption, we can find that the whole spectra has a certain change, particularly active groups (such as amide groups of the protein, hydroxy, carboxyl and phosphate group) are involved in the biosorption process. Then, there is a new peak at 906 cm(-1) and it is a stretching vibration peak of UO2(2+). Obviously, it is possible that as an anti radiation microorganism, Deinococcus radiodurans could be used for removing radionuclide uranium in radiation environment.

  6. Microbial transformation of uranium in wastes

    SciTech Connect

    Francis, A.J.; Dodge, C.J.; Gillow, J.B.; Cline, J.E.; Oak Ridge Y-12 Plant, TN )

    1989-01-01

    Contamination of soils, water, and sediments by radionuclides and toxic metals from the disposal of uranium processing wastes is a major national concern. Although much is known about the physico- chemical aspects of U, we have little information on the effects of aerobic and anaerobic microbial activities on the mobilization or immobilization of U and other toxic metals in mixed wastes. In order to understand the mechanisms of microbial transformations of uranium, we examined a contaminated pond sediment and a sludge sample from the uranium processing facility at Y-12 Plant, Oak Ridge, TN. The uranium concentration in the sediment and sludge samples was 923 and 3080 ug/g dry wt, respectively. In addition to U, the sediment and sludge samples contained high levels of toxic metals such as Cd, Cr, Cu, Hg, Pb, Ni, and Zn. The association of uranium with the various mineral fractions of the sediment and sludge was determined by selective chemical extraction techniques. Uranium was associated to varying degrees with the exchangeable carbonate, iron oxide, organic, and inert fractions in both samples. Initial results in samples amended with carbon and nitrogen indicate immobilization of U due to enhanced indigenous microbial activity under anaerobic conditions. 23 refs., 4 figs., 5 tabs.

  7. The United States Uranium Industry, 1993

    SciTech Connect

    Chenoweth, W.L.

    1993-08-01

    Low prices and foreign competition continue to plague the United States uranium industry. For eight years (1984-1991) the Secretary of Energy has declared the industry to be nonviable. A similar declaration is expected late in 1993 for 1992. Surface drilling for uranium in 1993 is expected to be about 1 million ft., because deposits are developed prior to mining. Drilling for claim assessment purposes has ceased due to changes in the mining law. All conventional mining and milling in the United States ceased in early 1992 when the last open-pit mine closed. Underground mining ceased in late 1990. Current uranium production is from solution mining (in-situ leaching) in Wyoming, Texas, and Nebraska. Uranium is recovered from Florida phosphate rock processed in Louisiana and from mine water in New Mexico. Uranium concentrate production in 1993 is expected to be about 5 million lbs U[sub 3]O[sub 8]. The United States has large reserves of uranium, but a significant price increase is needed for the industry to rebound.

  8. Are anthropogenic aerosols affecting rainfall?

    NASA Astrophysics Data System (ADS)

    Junkermann, Wolfgang; Hacker, Jorg

    2013-04-01

    Modification of cloud microphysics by anthropogenic aerosols is well known since several decades. Whether the underlying processes leads to changes in precipitation is by far less confirmed. Several different factors affect the production of rain in a way that a causality between increasing aerosol load in the atmosphere and a change of annual rainfall is very difficult to confirm. What would be expected as an effect of additional cloud condensation nuclei is a shift in the spatial and temporal rainfall distribution towards a lower number of days with low rain intensity and more frequent or more vigorous single events. In fact such a shift has been observed in several locations worldwide and has been suggested to be caused by increasing aerosol load, however, without further specification of the nature and number of the aerosols involved. Measurements of aerosols which might be important for cloud properties are extremely sparse and no long term monitoring data sets are available up to now. The problem of missing long term aerosol data that could be compared to available long term meteorological data sets can possibly be resolved in certain areas where well characterized large anthropogenic aerosol sources were installed in otherwise pristine areas without significant changes in land use over several decades. We investigated aerosol sources and current aerosol number, size and spatial distributions with airborne measurements in the planetary boundary layer over two regions in Australia that are reported to suffer from extensive drought despite the fact that local to regional scale water vapor in the atmosphere is slowly and constantly increasing. Such an increase of the total water in the planetary boundary layer would imply also an increase in annual precipitation as observed in many other locations elsewhere. The observed decline of rainfall in these areas thus requires a local to regional scale physical process modifying cloud properties in a way that rain

  9. Investigation of Great Basin big sagebrush and black greasewood as biogeochemical indicators of uranium mineralization. Final report. National Uranium Resource Evaluation

    SciTech Connect

    Diebold, F.E.; McGrath, S.

    1982-11-01

    The effects of varying phosphate concentrations in natural aqueous systems upon the uptake of uranium by big sagebrush (Artemesia tridentata subsp. tridentata) and black greasewood (Sarcobatus vermiculatus (Hook) Torr.) were investigated. Two separate growth experiments with five drip-flow hyroponic units were used and plant seedlings were grown for 60 days in solutions of varying phosphate and uranium concentrations. Successful growth experiments were obtained only for big sagebrush; black greasewood did not sustain sufficient growth. The phosphate concentration of the water did affect the uptake of uranium by the big sagebrush, and this effect is most pronounced in the region of higher concentrations of uranium in the water. The ratio of the concentration of uranium in the plant to that in the water was observed to decrease with increasing uranium concentration in solution. This is indicative of an absorption barrier in the plants. The field data shows that big sagebrush responds to uranium concentrations in the soil water and not the groundwater. The manifestation of these results is that the use of big sagebrush as a biogeochemical indicator of uranium is not recommended. Since the concentration of phosphate must also be knwon in the water supplying the uranium to the plant, one should analyze this natural aqueous phase as a hydrochemical indicator rather than the big sagebrush.

  10. Anthropogenic Carbon Pump in an Urbanized Estuary

    NASA Astrophysics Data System (ADS)

    Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

    2015-12-01

    The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

  11. Uranium industry annual 1993

    SciTech Connect

    Not Available

    1994-09-01

    Uranium production in the United States has declined dramatically from a peak of 43.7 million pounds U{sub 3}O{sub 8} (16.8 thousand metric tons uranium (U)) in 1980 to 3.1 million pounds U{sub 3}O{sub 8} (1.2 thousand metric tons U) in 1993. This decline is attributed to the world uranium market experiencing oversupply and intense competition. Large inventories of uranium accumulated when optimistic forecasts for growth in nuclear power generation were not realized. The other factor which is affecting U.S. uranium production is that some other countries, notably Australia and Canada, possess higher quality uranium reserves that can be mined at lower costs than those of the United States. Realizing its competitive advantage, Canada was the world`s largest producer in 1993 with an output of 23.9 million pounds U{sub 3}O{sub 8} (9.2 thousand metric tons U). The U.S. uranium industry, responding to over a decade of declining market prices, has downsized and adopted less costly and more efficient production methods. The main result has been a suspension of production from conventional mines and mills. Since mid-1992, only nonconventional production facilities, chiefly in situ leach (ISL) mining and byproduct recovery, have operated in the United States. In contrast, nonconventional sources provided only 13 percent of the uranium produced in 1980. ISL mining has developed into the most cost efficient and environmentally acceptable method for producing uranium in the United States. The process, also known as solution mining, differs from conventional mining in that solutions are used to recover uranium from the ground without excavating the ore and generating associated solid waste. This article describes the current ISL Yang technology and its regulatory approval process, and provides an analysis of the factors favoring ISL mining over conventional methods in a declining uranium market.

  12. Anthropogenic modification of the oceans.

    PubMed

    Tyrrell, Toby

    2011-03-13

    Human activities are altering the ocean in many different ways. The surface ocean is warming and, as a result, it is becoming more stratified and sea level is rising. There is no clear evidence yet of a slowing in ocean circulation, although this is predicted for the future. As anthropogenic CO(2) permeates into the ocean, it is making sea water more acidic, to the detriment of surface corals and probably many other calcifiers. Once acidification reaches the deep ocean, it will become more corrosive to CaCO(3), leading to a considerable reduction in the amount of CaCO(3) accumulating on the deep seafloor. There will be a several thousand-year-long interruption to CaCO(3) sedimentation at many points on the seafloor. A curious feedback in the ocean, carbonate compensation, makes it more likely that global warming and sea-level rise will continue for many millennia after CO(2) emissions cease.

  13. Uranium Contamination at the 300 Area of the Hanford Site

    SciTech Connect

    Brown, Christopher F.; Serne, R. Jeffrey; Krupka, Kenneth M.; Pierce, Eric M.; Lindberg, Michael J.

    2005-01-24

    Release rates of uranium from contaminated sediments are dependent on several key environmental factors which significantly influence the fate and transport of uranium in sediments and groundwater. Two of these factors include the form(s) in which the uranium contamination exists in the sediments and the compositions of pore fluids and groundwater that will react with these sediments. Solid-phase characterization of one contaminated sample was used in conjunction with semi-selective extraction analyses of six samples collected from the 300 Area of the U.S. Department of Energy’s Hanford Site to identify the form of uranium in the sediments. Static and flow-through column leaching experiments were used to evaluate the effect of solution composition (i.e., ionic strength and carbonate concentration) on the leach rates of uranium from these sediments. Results of scanning electron microscopy analyses indicated that the majority of the uranium in the most contaminated sediment was present as discrete uranium phases (possibly as a calcium uranyl silicate) and co-precipitates. Column leach tests showed that uranium effluent concentrations did not achieve steady-state conditions over the duration of the experiments (several months); they continued to decrease slowly over time, indicating that the release of uranium from the contaminated sediments was a multi-rate kinetically controlled process. Subsequent static leach experiments on the residual column leached material indicated that uranium release from the contaminated sediments was highly dependent on U(VI) aqueous complexation with carbonate, with the percentage of remobilized uranium ranging from 0.05 to 27% over a range of carbonate solution concentrations from 0.87 to 12.2 mM, respectively.

  14. Neptunium(V) Incorporation/Sorption with Uranium(VI) Alteration Products

    SciTech Connect

    Friese, Judah I.; Douglas, Matthew; Buck, Edgar C.; Clark, Susan B.; Hanson, Brady D.

    2004-04-01

    An initial uranium phase that has been observed to form during the corrosion of spent nuclear fuel is the uranium oxy-hydroxide metaschoepite. It has been proposed that neptunium(V) solubility can be limited by its association with this uranium phase. Metaschoepite has been synthesized in the presence of neptunium(V) over the pH range modeled in the proposed Yucca Mountain geologic repository. Uranium (VI) phaseswere synthesized by varying pH and neptunium concentrations. Results of neptunium association with the uranium alteration phases are presented and the relationship to dissolved neptunium concentrations discussed.

  15. Uranium: A Dentist's perspective.

    PubMed

    Toor, R S S; Brar, G S

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% - 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion replaces calcium in the hydroxyapatite complex of the bone crystal. Although in North India, there is a risk of radiological toxicity from orally ingested natural uranium, the principal health effects are chemical toxicity. The skeleton and kidney are the primary sites of uranium accumulation. Acute high dose of uranyl nitrate delays tooth eruption, and mandibular growth and development, probably due to its effect on target cells. Based on all previous research and recommendations, the role of a dentist is to educate the masses about the adverse effects of uranium on the overall as well as the dental health. The authors recommended that apart from the discontinuation of the addition of uranium to porcelain, the Public community water supplies must also comply with the Environmental Protection Agency (EPA) standards of uranium levels being not more than 30 ppb (parts per billion).

  16. DECONTAMINATION OF URANIUM

    DOEpatents

    Spedding, F.H.; Butler, T.A.

    1962-05-15

    A process is given for separating fission products from uranium by extracting the former into molten aluminum. Phase isolation can be accomplished by selectively hydriding the uranium at between 200 and 300 deg C and separating the hydride powder from coarse particles of fissionproduct-containing aluminum. (AEC)

  17. Uranium and Thorium

    ERIC Educational Resources Information Center

    Finch, Warren I.

    1978-01-01

    The results of President Carter's policy on non-proliferation of nuclear weapons are expected to slow the growth rate in energy consumption, put the development of the breeder reactor in question, halt plans to reprocess and recycle uranium and plutonium, and expand facilities to supply enriched uranium. (Author/MA)

  18. Uranium: A Dentist's perspective

    PubMed Central

    Toor, R. S. S.; Brar, G. S.

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% – 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion replaces calcium in the hydroxyapatite complex of the bone crystal. Although in North India, there is a risk of radiological toxicity from orally ingested natural uranium, the principal health effects are chemical toxicity. The skeleton and kidney are the primary sites of uranium accumulation. Acute high dose of uranyl nitrate delays tooth eruption, and mandibular growth and development, probably due to its effect on target cells. Based on all previous research and recommendations, the role of a dentist is to educate the masses about the adverse effects of uranium on the overall as well as the dental health. The authors recommended that apart from the discontinuation of the addition of uranium to porcelain, the Public community water supplies must also comply with the Environmental Protection Agency (EPA) standards of uranium levels being not more than 30 ppb (parts per billion). PMID:24478959

  19. Uranium triamidoamine chemistry.

    PubMed

    Gardner, Benedict M; Liddle, Stephen T

    2015-07-01

    Triamidoamine (Tren) complexes of the p- and d-block elements have been well-studied, and they display a diverse array of chemistry of academic, industrial and biological significance. Such in-depth investigations are not as widespread for Tren complexes of uranium, despite the general drive to better understand the chemical behaviour of uranium by virtue of its fundamental position within the nuclear sector. However, the chemistry of Tren-uranium complexes is characterised by the ability to stabilise otherwise reactive, multiply bonded main group donor atom ligands, construct uranium-metal bonds, promote small molecule activation, and support single molecule magnetism, all of which exploit the steric, electronic, thermodynamic and kinetic features of the Tren ligand system. This Feature Article presents a current account of the chemistry of Tren-uranium complexes.

  20. Uranium dioxide electrolysis

    DOEpatents

    Willit, James L.; Ackerman, John P.; Williamson, Mark A.

    2009-12-29

    This is a single stage process for treating spent nuclear fuel from light water reactors. The spent nuclear fuel, uranium oxide, UO.sub.2, is added to a solution of UCl.sub.4 dissolved in molten LiCl. A carbon anode and a metallic cathode is positioned in the molten salt bath. A power source is connected to the electrodes and a voltage greater than or equal to 1.3 volts is applied to the bath. At the anode, the carbon is oxidized to form carbon dioxide and uranium chloride. At the cathode, uranium is electroplated. The uranium chloride at the cathode reacts with more uranium oxide to continue the reaction. The process may also be used with other transuranic oxides and rare earth metal oxides.

  1. METHOD FOR PURIFYING URANIUM

    DOEpatents

    Kennedy, J.W.; Segre, E.G.

    1958-08-26

    A method is presented for obtaining a compound of uranium in an extremely pure state and in such a condition that it can be used in determinations of the isotopic composition of uranium. Uranium deposited in calutron receivers is removed therefrom by washing with cold nitric acid and the resulting solution, coataining uranium and trace amounts of various impurities, such as Fe, Ag, Zn, Pb, and Ni, is then subjected to various analytical manipulations to obtain an impurity-free uranium containing solution. This solution is then evaporated on a platinum disk and the residue is ignited converting it to U2/sub 3//sub 8/. The platinum disk having such a thin film of pure U/sub 2/O/sub 8/ is suitable for use with isotopic determination techaiques.

  2. URANIUM PRECIPITATION PROCESS

    DOEpatents

    Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

    1957-12-01

    A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

  3. Anthropogenic Disturbance of Element Cycles at the Earth's Surface

    NASA Astrophysics Data System (ADS)

    Sen, I. S.; Peucker-Ehrenbrink, B.

    2012-12-01

    The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts [1]. We determine anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compared it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions and - for helium - hydrodynamic escape from the Earth's atmosphere. In addition, we introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporated uncertainties of element mass fluxes through Monte Carlo simulations [2]. Our assessment indicates that anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium are greater than the respective natural fluxes. For these elements mining is the major factor of human dominance, whereas petroleum burning strongly influence the surficial cycle of rhenium. Apart from these 11 elements there are 15 additional elements whose anthropogenic fluxes may surpass their corresponding natural fluxes. Anthropogenic fluxes of the remaining elements are smaller than their corresponding natural fluxes although a significant human influence is observed for all of them. For example, ~20% of the annual fluxes of C, N, and P can be attributed to human activities. Such disturbances, though small compared with natural fluxes, can significantly alter concentrations in near-surface reservoirs and affect ecosystems if they are sustained over time scales similar to or longer than the residence time of elements in the respective reservoir. Examples are the continuing input of CO2 to the atmosphere that

  4. Anthropogenic impacts on the biogeochemistry and cycling of antimony.

    PubMed

    Shotyk, William; Krachler, Michael; Chen, Bin

    2005-01-01

    Antimony is a potentially toxic trace element with no known biological function. Antimony is commonly enriched in coals, and fossil fuel combustion appears to be the largest single source of anthropogenic Sb to the global atmosphere. Abundant in sulfide minerals, its emission to the atmosphere from anthropogenic activities is linked to the mining and metallurgy of non-ferrous metals, especially Pb, Cu, and Zn. In particular, the geochemical and mineralogical association of Sb with Pb minerals implies that, like Pb, Sb has been emitted to the environment for thousands of years because of Pb mining, smelting, and refining. In the US alone, there are more than 400 former secondary lead smelting operations and worldwide there are 133 Pb-Zn smelters in operation today. Antimony is used in creating and improving dozens of industrial and commercial materials including various alloys, ceramics, glasses, plastics, and synthetic fabrics, making waste incineration another important source of Sb to the environment. Enrichments of Sb in atmospheric aerosols, plants, soils, sediments, as well as alpine and polar snow and ice suggest that Sb contamination is extensive, but there are very few quantitative studies of the geographic extent, intensity, and chronology of this contamination. There is an urgent need to quantify the extent of human impacts and how these have changed with time. The decreasing inventories of anthropogenic Sb with time in peat cores from Switzerland and Scotland suggest that the atmospheric Sb flux may be declining, but there have been too few studies to make any general conclusions. In fact, some studies of sediments and biomonitors in central Europe show little decline in Sb concentrations during the past decades. There is an obvious need for reliable data from well dated archives such as polar snow and ice, peat bogs, and sediments. The air concentrations, extent of enrichment, particle size distribution, and rate of deposition of Sb in urban areas is

  5. A sensitive method for the determination of uranium in biological samples utilizing kinetic phosphorescence analysis (KPA).

    PubMed

    Hedaya, M A; Birkenfeld, H P; Kathren, R L

    1997-05-01

    Kinetic phosphorescence analysis is a technique that provides rapid, precise and accurate determination of uranium concentration in aqueous solutions. This technique utilizes a laser source to excite an aqueous solution of uranium, and measures the emission luminescence intensity over time to determine the luminescence decay profile. The lifetime of the luminescence decay profile and the linearity of the log luminescence intensity versus time profile are indications of the specificity of the technique for uranium determination. The luminescence intensity at the onset of decay (the initial luminescence intensity), which is the luminescence intensity at time zero after termination of the laser pulse used for excitation, is proportional to the uranium concentration in the sample. Calibration standards of known uranium concentrations are used to construct the calibration curve between the initial luminescence intensity and uranium concentration. This calibration curve is used to determine the uranium concentration of unknown samples from their initial luminescence intensity. We developed the sample preparation method that allows the determination of uranium concentrations in urine, plasma, kidney, liver, bone spleen and soft tissue samples. Tissue samples are subjected to dry-ashing in a muffle furnace at 600 degrees C and wet-ashing with concentrated nitric acid and hydrogen peroxide twice to destroy the organic component in the sample that may interfere with uranium determination by KPA. Samples are then solubilized in 0.82 M nitric acid prior to analysis by KPA. The assay calibration curves are linear and cover the range of uranium concentrations between 0.05 micrograms l-1 and 1000 micrograms l-1 (0.05-1000 ppb). The developed sample preparation procedures coupled with the KPA technique provide a specific, sensitive, precise and accurate method for the determination of uranium concentration in tissue samples. This method was used to quantify uranium in different

  6. 16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM RECOVERY PROCESSED RELATIVELY PURE MATERIALS AND SOLUTIONS AND SOLID RESIDUES WITH RELATIVELY LOW URANIUM CONTENT. URANIUM RECOVERY INVOLVED BOTH SLOW AND FAST PROCESSES. (4/4/66) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

  7. Anthropogenic climate change affects meteorological drought risk in Europe

    NASA Astrophysics Data System (ADS)

    Gudmundsson, L.; Seneviratne, S. I.

    2016-04-01

    Drought constitutes a significant natural hazard in Europe, impacting societies and ecosystems across the continent. Climate model simulations with increasing greenhouse gas concentrations project increased drought risk in southern Europe, and on the other hand decreased drought risk in the north. Observed changes in water balance components and drought indicators resemble the projected pattern. However, assessments of possible causes of the reported regional changes have so far been inconclusive. Here we investigate whether anthropogenic emissions have altered past and present meteorological (precipitation) drought risk. For doing so we first estimate the magnitude of 20 year return period drought years that would occur without anthropogenic effects on the climate. Subsequently we quantify to which degree the occurrence probability, i.e. the risk, of these years has changed if anthropogenic climate change is accounted for. Both an observational and a climate model-based assessment suggest that it is >95% likely that human emissions have increased the probability of drought years in the Mediterranean, whereas it is >95% likely that the probability of dry years has decreased in northern Europe. In central Europe the evidence is inconclusive. The results highlight that anthropogenic climate change has already increased drought risk in southern Europe, stressing the need to develop efficient mitigation measures.

  8. Uranium quantification in semen by inductively coupled plasma mass spectrometry.

    PubMed

    Todorov, Todor I; Ejnik, John W; Guandalini, Gustavo; Xu, Hanna; Hoover, Dennis; Anderson, Larry; Squibb, Katherine; McDiarmid, Melissa A; Centeno, Jose A

    2013-01-01

    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4-7% RSD and spike recoveries were 97-100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n=10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans' semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments.

  9. Distribution and potential health risk of groundwater uranium in Korea.

    PubMed

    Shin, Woosik; Oh, Jungsun; Choung, Sungwook; Cho, Byong-Wook; Lee, Kwang-Sik; Yun, Uk; Woo, Nam-Chil; Kim, Hyun Koo

    2016-11-01

    Chronic exposure even to extremely low specific radioactivity of natural uranium in groundwater results in kidney problems and potential toxicity in bones. This study was conducted to assess the potential health risk via intake of the groundwater containing uranium, based on the determination of the uranium occurrence in groundwater. The groundwater was investigated from a total of 4140 wells in Korea. Most of the groundwater samples showed neutral pH and (sub-)oxic condition that was influenced by the mixing with shallow groundwater due to long-screened (open) wells. High uranium contents exceeding the WHO guideline level of 30 μg L(-1) were observed in the 160 wells located mainly in the plutonic bedrock regions. The statistical analysis suggested that the uranium component was present in groundwater by desorption and re-dissolution processes. Predominant uranium phases were estimated to uranyl carbonates under the Korean groundwater circumstances. These mobile forms of uranium and oxic condition facilitate the increase of potential health risk downgradient. In particular, long-term intake of groundwater containing >200 μg U L(-1) may induce internal exposure to radiation as well as the effects of chemical toxicity. These high uranium concentrations were found in twenty four sampling wells of rural areas in this study, and they were mainly used for drinking. Therefore, the high-level uranium wells and neighboring areas must be properly managed and monitored to reduce the exposure risk for the residents by drinking groundwater. PMID:27522182

  10. Distribution and potential health risk of groundwater uranium in Korea.

    PubMed

    Shin, Woosik; Oh, Jungsun; Choung, Sungwook; Cho, Byong-Wook; Lee, Kwang-Sik; Yun, Uk; Woo, Nam-Chil; Kim, Hyun Koo

    2016-11-01

    Chronic exposure even to extremely low specific radioactivity of natural uranium in groundwater results in kidney problems and potential toxicity in bones. This study was conducted to assess the potential health risk via intake of the groundwater containing uranium, based on the determination of the uranium occurrence in groundwater. The groundwater was investigated from a total of 4140 wells in Korea. Most of the groundwater samples showed neutral pH and (sub-)oxic condition that was influenced by the mixing with shallow groundwater due to long-screened (open) wells. High uranium contents exceeding the WHO guideline level of 30 μg L(-1) were observed in the 160 wells located mainly in the plutonic bedrock regions. The statistical analysis suggested that the uranium component was present in groundwater by desorption and re-dissolution processes. Predominant uranium phases were estimated to uranyl carbonates under the Korean groundwater circumstances. These mobile forms of uranium and oxic condition facilitate the increase of potential health risk downgradient. In particular, long-term intake of groundwater containing >200 μg U L(-1) may induce internal exposure to radiation as well as the effects of chemical toxicity. These high uranium concentrations were found in twenty four sampling wells of rural areas in this study, and they were mainly used for drinking. Therefore, the high-level uranium wells and neighboring areas must be properly managed and monitored to reduce the exposure risk for the residents by drinking groundwater.

  11. Controlling intake of uranium in the workplace: Applications of biokinetic modeling and occupational monitoring data

    SciTech Connect

    Leggett, Richard Wayne; Eckerman, Keith F; McGinn, Wilson; Meck, Dr. Robert A.

    2012-01-01

    This report provides methods for interpreting and applying occupational uranium monitoring data. The methods are based on current international radiation protection guidance, current information on the chemical toxicity of uranium, and best available biokinetic models for uranium. Emphasis is on air monitoring data and three types of bioassay data: the concentration of uranium in urine; the concentration of uranium in feces; and the externally measured content of uranium in the chest. Primary Reference guidance levels for prevention of chemical effects and limitation of radiation effects are selected based on a review of current scientific data and regulatory principles for setting standards. Generic investigation levels and immediate action levels are then defined in terms of these primary guidance levels. The generic investigation and immediate actions levels are stated in terms of radiation dose and concentration of uranium in the kidneys. These are not directly measurable quantities, but models can be used to relate the generic levels to the concentration of uranium in air, urine, or feces, or the total uranium activity in the chest. Default investigation and immediate action levels for uranium in air, urine, feces, and chest are recommended for situations in which there is little information on the form of uranium taken into the body. Methods are prescribed also for deriving case-specific investigation and immediate action levels for uranium in air, urine, feces, and chest when there is sufficient information on the form of uranium to narrow the range of predictions of accumulation of uranium in the main target organs for uranium: kidneys for chemical effects and lungs for radiological effects. In addition, methods for using the information herein for alternative guidance levels, different from the ones selected for this report, are described.

  12. Uranium and cesium diffusion in fuel cladding of electrogenerating channel

    SciTech Connect

    Vasil’ev, I. V. Ivanov, A. S.; Churin, V. A.

    2014-12-15

    The results of reactor tests of a carbonitride fuel in a single-crystal cladding from a molybdenum-based alloy can be used in substantiating the operational reliability of fuels in developing a project of a megawatt space nuclear power plant. The results of experimental studies of uranium and cesium penetration into the single-crystal cladding of fuel elements with a carbonitride fuel are interpreted. Those fuel elements passed nuclear power tests in the Ya-82 pilot plant for 8300 h at a temperature of about 1500°C. It is shown that the diffusion coefficients for uranium diffusion into the cladding are virtually coincident with the diffusion coefficients measured earlier for uranium diffusion into polycrystalline molybdenum. It is found that the penetration of uranium into the cladding is likely to occur only in the case of a direct contact between the cladding and fuel. The experimentally observed nonmonotonic uranium-concentration profiles are explained in terms of predominant uranium diffusion along grain boundaries. It is shown that a substantially nonmonotonic behavior observed in our experiment for the uranium-concentration profile may be explained by the presence of a polycrystalline structure of the cladding in the surface region from its inner side. The diffusion coefficient is estimated for the grain-boundary diffusion of uranium. The diffusion coefficients for cesium are estimated on the basis of experimental data obtained in the present study.

  13. PROCESS OF RECOVERING URANIUM

    DOEpatents

    Kilner, S.B.

    1959-12-29

    A method is presented for separating and recovering uranium from a complex mixure of impurities. The uranium is dissolved to produce an aqueous acidic solution including various impurities. In accordance with one method, with the uranium in the uranyl state, hydrogen cyanide is introduced into the solution to complex the impurities. Subsequently, ammonia is added to the solution to precipitate the uraniunn as ammonium diuranate away from the impurities in the solution. Alternatively, the uranium is precipitated by adding an alkaline metal hydroxide. In accordance with the second method, the uranium is reduced to the uranous state in the solution. The reduced solution is then treated with solid alkali metal cyanide sufficient to render the solution about 0.1 to 1.0 N in cyanide ions whereat cyanide complex ions of the metal impurities are produced and the uranium is simultaneously precipituted as uranous hydroxide. Alternatively, hydrogen cyanide may be added to the reduced solution and the uranium precipitated subsequently by adding ammonium hydroxide or an alkali metal hydroxide. Other refinements of the method are also disclosed.

  14. Anthropogenic triggering of large earthquakes.

    PubMed

    Mulargia, Francesco; Bizzarri, Andrea

    2014-01-01

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1-10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor "foreshocks", since the induction may occur with a delay up to several years.

  15. Anthropogenic triggering of large earthquakes.

    PubMed

    Mulargia, Francesco; Bizzarri, Andrea

    2014-01-01

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1-10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor "foreshocks", since the induction may occur with a delay up to several years. PMID:25156190

  16. How anthropogenic noise affects foraging.

    PubMed

    Luo, Jinhong; Siemers, Björn M; Koselj, Klemen

    2015-09-01

    The influence of human activity on the biosphere is increasing. While direct damage (e.g. habitat destruction) is relatively well understood, many activities affect wildlife in less apparent ways. Here, we investigate how anthropogenic noise impairs foraging, which has direct consequences for animal survival and reproductive success. Noise can disturb foraging via several mechanisms that may operate simultaneously, and thus, their effects could not be disentangled hitherto. We developed a diagnostic framework that can be applied to identify the potential mechanisms of disturbance in any species capable of detecting the noise. We tested this framework using Daubenton's bats, which find prey by echolocation. We found that traffic noise reduced foraging efficiency in most bats. Unexpectedly, this effect was present even if the playback noise did not overlap in frequency with the prey echoes. Neither overlapping noise nor nonoverlapping noise influenced the search effort required for a successful prey capture. Hence, noise did not mask prey echoes or reduce the attention of bats. Instead, noise acted as an aversive stimulus that caused avoidance response, thereby reducing foraging efficiency. We conclude that conservation policies may seriously underestimate numbers of species affected and the multilevel effects on animal fitness, if the mechanisms of disturbance are not considered.

  17. Anthropogenic Triggering of Large Earthquakes

    PubMed Central

    Mulargia, Francesco; Bizzarri, Andrea

    2014-01-01

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1–10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor “foreshocks”, since the induction may occur with a delay up to several years. PMID:25156190

  18. India's Worsening Uranium Shortage

    SciTech Connect

    Curtis, Michael M.

    2007-01-15

    As a result of NSG restrictions, India cannot import the natural uranium required to fuel its Pressurized Heavy Water Reactors (PHWRs); consequently, it is forced to rely on the expediency of domestic uranium production. However, domestic production from mines and byproduct sources has not kept pace with demand from commercial reactors. This shortage has been officially confirmed by the Indian Planning Commission’s Mid-Term Appraisal of the country’s current Five Year Plan. The report stresses that as a result of the uranium shortage, Indian PHWR load factors have been continually decreasing. The Uranium Corporation of India Ltd (UCIL) operates a number of underground mines in the Singhbhum Shear Zone of Jharkhand, and it is all processed at a single mill in Jaduguda. UCIL is attempting to aggrandize operations by establishing new mines and mills in other states, but the requisite permit-gathering and development time will defer production until at least 2009. A significant portion of India’s uranium comes from byproduct sources, but a number of these are derived from accumulated stores that are nearing exhaustion. A current maximum estimate of indigenous uranium production is 430t/yr (230t from mines and 200t from byproduct sources); whereas, the current uranium requirement for Indian PHWRs is 455t/yr (depending on plant capacity factor). This deficit is exacerbated by the additional requirements of the Indian weapons program. Present power generation capacity of Indian nuclear plants is 4350 MWe. The power generation target set by the Indian Department of Atomic Energy (DAE) is 20,000 MWe by the year 2020. It is expected that around half of this total will be provided by PHWRs using indigenously supplied uranium with the bulk of the remainder provided by breeder reactors or pressurized water reactors using imported low-enriched uranium.

  19. New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

    SciTech Connect

    Not Available

    2011-06-22

    Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (XAS), and was implemented at the site of a former uranium mill in Rifle, CO. Glass columns filled with bioactive Rifle sediments were deployed in wells in the contaminated Rifle aquifer and amended with a hexavalent uranium (U(VI)) stock solution to increase uranium concentration while maintaining field conditions. This sediment was harvested and XAS was utilized to analyze the oxidation state and local molecular structure of the uranium in sediment samples. Extended X-Ray Absorption Fine Structure (EXAFS) data was collected and compared to known uranium spectra to determine the local molecular structure of the uranium in the sediment. Fitting was used to determine that the field site sediments did not contain uraninite (UO{sub 2}), indicating that models based on bioreduction using pure bacterial cultures are not accurate for bioremediation in the field. Stability tests on the monomeric tetravalent uranium (U(IV)) produced by bioremediation are needed in order to assess the efficacy of acetate-stimulation bioremediation.

  20. Caracterisation of anthropogenic contribution to the coastal fluorescent organic matter

    NASA Astrophysics Data System (ADS)

    El Nahhal, Ibrahim; Nouhi, Ayoub; Mounier, Stéphane

    2015-04-01

    It is known that most of the coastal fluorescent organic matter is of a terrestrial origin (Parlanti, 2000; Tedetti, Guigue, & Goutx, 2010). However, the contribution of the anthropogenic organic matter to this pool is not well defined and evaluated. In this work the monitoring of little bay (Toulon Bay, France) was done in the way to determine the organic fluorescent response during a winter period. The sampling campaign consisted of different days during the month of December, 2014 ( 12th, 15th, 17th, 19th) on 21 different sampling sites for the fluorescence measurements (without any filtering of the samples) and the whole month of December for the bacterial and the turbidity measurements. Excitation Emission Matrices (EEMs) of fluorescence (from 200 to 400 nm and 220 to 420 nm excitation and emission range) were treated by parallel factor analysis (PARAFAC).The parafac analysis of the EEM datasets was conducted using PROGMEEF software in Matlab langage. On the same time that the turbidity and bacterial measurement (particularly the E.Coli concentration) were determined. The results gives in a short time range, information on the the contribution of the anthropogenic inputs to the coastal fluorescent organic matter. In addition, the effect of salinity on the photochemical degradation of the anthropogenic organic matter (especially those from wastewater treatment plants) will be studied to investigate their fate in the water end member by the way of laboratory experiments. Parlanti, E. (2000). Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs. Organic Geochemistry, 31(12), 1765-1781. doi:10.1016/S0146-6380(00)00124-8 Tedetti, M., Guigue, C., & Goutx, M. (2010). Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters. Marine Pollution Bulletin, 60(3), 350-62. doi:10.1016/j.marpolbul.2009.10.018

  1. Floating plant can get uranium from seawater

    SciTech Connect

    Not Available

    1984-02-01

    A floating plant has been designed to extract uranium from seawater using solid adsorbents. Ore is removed from the adsorbent material by means of a solvent and concentrated in ion exchangers. Seawater is supplied to the adsorbent inside by wave energy and is based on the principle that waves will rush up a sloping plane that is partly submerged and fill a reservoir to a level higher than the still water level in the sea. The company projects that an offshore plant for recovering 600 tons of uranium/yr would comprise 22 floating concrete units, each measuring 430 x 75 meters.

  2. Recovery of uranium values

    DOEpatents

    Brown, K. B.; Crouse, Jr., D. J.; Moore, J. G.

    1959-03-10

    A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine fn the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected anine dissolved in a nonpolar waterimmiscible organfc solvent such as kerosene. The uranium which is substantially completely extracted by the organic phase may be stripped therefrom by water, and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

  3. RECOVERY OF URANIUM VALUES

    DOEpatents

    Brown, K.B.; Crouse, D.J. Jr.; Moore, J.G.

    1959-03-10

    A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine in the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected amine dissolved in a nonpolar water-immiscible organic solvent such as kerosene. The uranium which is substantially completely exiracted by the organic phase may be stripped therefrom by waters and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

  4. Development of Novel Sorbents for Uranium Extraction from Seawater

    SciTech Connect

    Lin, Wenbin; Taylor-Pashow, Kathryn

    2014-01-08

    As the uranium resource in terrestrial ores is limited, it is difficult to ensure a long-term sustainable nuclear energy technology. The oceans contain approximately 4.5 billion tons of uranium, which is one thousand times the amount of uranium in terrestrial ores. Development of technologies to recover the uranium from seawater would greatly improve the uranium resource availability, sustaining the fuel supply for nuclear energy. Several methods have been previously evaluated including solvent extraction, ion exchange, flotation, biomass collection, and adsorption; however, none have been found to be suitable for reasons such as cost effectiveness, long term stability, and selectivity. Recent research has focused on the amidoxime functional group as a promising candidate for uranium sorption. Polymer beads and fibers have been functionalized with amidoxime functional groups, and uranium adsorption capacities as high as 1.5 g U/kg adsorbent have recently been reported with these types of materials. As uranium concentration in seawater is only ~3 ppb, great improvements to uranium collection systems must be made in order to make uranium extraction from seawater economically feasible. This proposed research intends to develop transformative technologies for economic uranium extraction from seawater. The Lin group will design advanced porous supports by taking advantage of recent breakthroughs in nanoscience and nanotechnology and incorporate high densities of well-designed chelators into such nanoporous supports to allow selective and efficient binding of uranyl ions from seawater. Several classes of nanoporous materials, including mesoporous silica nanoparticles (MSNs), mesoporous carbon nanoparticles (MCNs), meta-organic frameworks (MOFs), and covalent-organic frameworks (COFs), will be synthesized. Selective uranium-binding liagnds such as amidoxime will be incorporated into the nanoporous materials to afford a new generation of sorbent materials that will be

  5. Effect of anthropogenic sulfate aerosols on low-level cloud albedo over oceans

    NASA Technical Reports Server (NTRS)

    Kim, Youngseung; Cess, Robert D.

    1993-01-01

    By reducing cloud droplet size, anthropogenic sulfate aerosols are capable of increasing cloud albedo and thus possibly changing the climate. To test the detectability of this effect, we examined satellite-measured low-level cloud albedo off the east coasts of North America and Asia at midlatitudes where anthropogenic sulfate sources are large and aerosols are transported eastward over the oceans by prevailing westerlies. The satellite data demonstrate enhanced cloud albedo near the coastal boundaries where sulfate concentrations are large. Similar trends are absent over ocean regions of the Southern Hemisphere that are removed from anthropogenic sulfate sources.

  6. Contemporary anthropogenic silver cycle: a multilevel analysis.

    PubMed

    Johnson, Jeremiah; Jirikowic, Julie; Bertram, Marlen; van Beers, D; Gordon, R B; Henderson, Kathryn; Klee, R J; Lanzano, Ted; Lifset, R; Oetjen, Lucia; Graedel, T E

    2005-06-15

    Anthropogenic cycling of silver in 1997 is presented using three discrete governmental units: 64 countries encompassing what we believe to be over 90% of global silver flows, 9 world regions, and the entire planet. Using material flow analysis (MFA) techniques, the country level cycles are aggregated to produce the regional cycles, which are used to form a "best estimate" global cycle. Interesting findings include the following: (1) several silver-mining countries export ore and concentrate but also import silver-containing semiproducts and products; (2) the level of development for a country, as indicated by the gross domestic product, is a fair indicator of silver use, but several significant outliers exist; (3) the countries with the greatest mine production include Mexico, the United States, Peru, and China, whereas the United States, Japan, India, Germany, and Italy lead in the fabrication and manufacture of products; (4) North America and Europe's use of silver products exceed that of other regions on a per capita basis; (5) global silver discards, including tailings and separation waste, totaled approximately 57% of the silver mined; (6) approximately 57% of the silver entering waste management globally is recycled; and (7) the amount of silver entering landfills globally is comparable to the amount found in tailings. The results of this MFA lay the basis for further analysis, which in turn can offer insight into natural resource policy, the characterization of environmental impact, and better resource management.

  7. Contemporary anthropogenic silver cycle: a multilevel analysis.

    PubMed

    Johnson, Jeremiah; Jirikowic, Julie; Bertram, Marlen; van Beers, D; Gordon, R B; Henderson, Kathryn; Klee, R J; Lanzano, Ted; Lifset, R; Oetjen, Lucia; Graedel, T E

    2005-06-15

    Anthropogenic cycling of silver in 1997 is presented using three discrete governmental units: 64 countries encompassing what we believe to be over 90% of global silver flows, 9 world regions, and the entire planet. Using material flow analysis (MFA) techniques, the country level cycles are aggregated to produce the regional cycles, which are used to form a "best estimate" global cycle. Interesting findings include the following: (1) several silver-mining countries export ore and concentrate but also import silver-containing semiproducts and products; (2) the level of development for a country, as indicated by the gross domestic product, is a fair indicator of silver use, but several significant outliers exist; (3) the countries with the greatest mine production include Mexico, the United States, Peru, and China, whereas the United States, Japan, India, Germany, and Italy lead in the fabrication and manufacture of products; (4) North America and Europe's use of silver products exceed that of other regions on a per capita basis; (5) global silver discards, including tailings and separation waste, totaled approximately 57% of the silver mined; (6) approximately 57% of the silver entering waste management globally is recycled; and (7) the amount of silver entering landfills globally is comparable to the amount found in tailings. The results of this MFA lay the basis for further analysis, which in turn can offer insight into natural resource policy, the characterization of environmental impact, and better resource management. PMID:16047806

  8. Recent changes in anthropogenic reactive nitrogen compounds

    NASA Astrophysics Data System (ADS)

    Andronache, Constantin

    2014-05-01

    Significant anthropogenic perturbations of the nitrogen cycle are the result of rapid population growth, with mounting need for food and energy production. The increase of reactive nitrogen compounds (such as NOx, HNO3, NH3, and N2O) has a significant impact on human health, environment, and climate. NOx emissions contribute to O3 chemistry, aerosol formation and acidic precipitation. Ammonia is a notable atmospheric pollutant that may deteriorate ecosystems and contribute to respiratory problems. It reacts with acidic gases to form aerosols or is deposited back to ecosystems. The application of fertilizers accounts for most of the N2O production, adding to greenhouse gas emissions. We analyze the change of some reactive nitrogen compounds based on observations, in eastern United States. Results show that the control of NOx and SO2 emissions over the last decades caused a significant decrease of acidic deposition. The nitrate deposition is highest in eastern US, while the ammonium ion concentration is highest in central US regions. Overall, the inorganic nitrogen wet deposition from nitrate and ammonium is enhanced in central, and eastern US. Research shows that sensitive ecosystems in northeastern regions exhibit a slow recovery from the accumulated effects of acidic deposition. Given the growing demand for nitrogen in agriculture and industry, we discuss possible pathways to reduce the impact of excess reactive nitrogen on the environment.

  9. Modeling fallout of anthropogenic 129I.

    PubMed

    Englund, Edvard; Aldahan, Ala; Possnert, Göran; Haltia-Hovi, Eeva; Hou, Xiaolin; Renberg, Ingmar; Saarinen, Timo

    2008-12-15

    Despite the relatively well-recognized emission rates of the anthropogenic 129I, there is little knowledge about the temporal fallout patterns and magnitude of fluxes since the start of the atomic era atthe early 1940s. We here present measurements of annual 129I concentrations in sediment archives from Sweden and Finland covering the period 1942-2006. The results revealed impression of 129I emissions from the nuclear reprocessing facility at Sellafield and La Hague and a clear Chernobyl fallout enhancement during 1986. In order to estimate relative contributions from the different sources, a numerical model approach was used taking into accountthe emission rates/estimated fallout, transport pathways, and the sediment system. The model outcomes suggest a relatively dominating marine source of 129I to north Europe compared to direct gaseous releases. A transfer rate of 129I from sea to atmosphere is derived for pertinent sea areas (English Channel, Irish Sea, and North Sea), which is estimated at 0.04 to 0.21 y(-1).

  10. Biomonitoring of environmental pollution by thorium and uranium in selected regions of the Republic of Kazakhstan.

    PubMed

    Zoriy, P; Ostapczuk, P; Dederichs, H; Höbig, J; Lennartz, R; Zoriy, M

    2010-05-01

    Two former uranium mines and a uranium reprocessing factory in the city of Aktau, Kazakhstan, may represent a risk of contaminating the surrounding areas by uranium and its daughter elements. One of the possible fingerprinting tools for studying the environmental contamination is using plant samples, collected in the surroundings of this city in 2007 and 2008. The distribution pattern of environmental pollution by uranium and thorium was evaluated by determining the thorium and uranium concentrations in plant samples (Artemisia austriaca) from the city of Aktau and comparing these results with those obtained for the same species of plants from an unpolluted area (town of Kurchatov). The determination of the uranium and thorium concentrations in different parts of A. austriaca plants collected from the analyzed areas demonstrated that the main contamination of the flora in areas surrounding the city of Aktau was due to dust transported by the wind from the uranium mines. The results obtained demonstrate that all the areas surrounding Aktau have a higher pollution level due to thorium and uranium than the control area (Kurchatov). A few "hot points" with high concentrations of uranium and thorium were found near the uranium reprocessing factory and the uranium mines.

  11. Effect of anthropogenic organic complexants on the solubility of Ni, Th, U(IV) and U(VI).

    PubMed

    Felipe-Sotelo, M; Edgar, M; Beattie, T; Warwick, P; Evans, N D M; Read, D

    2015-12-30

    The influence of anthropogenic organic complexants (citrate, EDTA and DTPA from 0.005 to 0.1M) on the solubility of nickel(II), thorium(IV) and uranium (U(IV) and U(VI)) has been studied. Experiments were carried out in 95%-saturated Ca(OH)2 solutions, representing the high pH conditions anticipated in the near field of a cementitious intermediate level radioactive waste repository. Results showed that Ni(II) solubility increased by 2-4 orders of magnitude in the presence of EDTA and DTPA and from 3 to 4 orders of magnitude in the case of citrate. Citrate had the greatest effect on the solubility of Th(IV) and U(IV)/(VI). XRD and SEM analyses indicate that the precipitates are largely amorphous; only in the case of Ni(II), is there some evidence of incipient crystallinity, in the form of Ni(OH)2 (theophrastite). A study of the effect of calcium suggests that U(VI) and Ni(II) may form metal-citrate-OH complexes stabilised by Ca(2+). Thermodynamic modelling underestimates the concentrations in solution in the presence of the ligands for all the elements considered here. Further investigation of the behaviour of organic ligands under hyperalkaline conditions is important because of the use of the thermodynamic constants in preparing the safety case for the geological disposal of radioactive wastes. PMID:26253235

  12. Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

    PubMed

    Viana, Inés G; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. PMID:23247291

  13. Attributing physical and biological impacts to anthropogenic climate change.

    PubMed

    Rosenzweig, Cynthia; Karoly, David; Vicarelli, Marta; Neofotis, Peter; Wu, Qigang; Casassa, Gino; Menzel, Annette; Root, Terry L; Estrella, Nicole; Seguin, Bernard; Tryjanowski, Piotr; Liu, Chunzhen; Rawlins, Samuel; Imeson, Anton

    2008-05-15

    Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here we show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone. Given the conclusions from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report that most of the observed increase in global average temperatures since the mid-twentieth century is very likely to be due to the observed increase in anthropogenic greenhouse gas concentrations, and furthermore that it is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent except Antarctica, we conclude that anthropogenic climate change is having a significant impact on physical and biological systems globally and in some continents. PMID:18480817

  14. Attributing physical and biological impacts to anthropogenic climate change.

    PubMed

    Rosenzweig, Cynthia; Karoly, David; Vicarelli, Marta; Neofotis, Peter; Wu, Qigang; Casassa, Gino; Menzel, Annette; Root, Terry L; Estrella, Nicole; Seguin, Bernard; Tryjanowski, Piotr; Liu, Chunzhen; Rawlins, Samuel; Imeson, Anton

    2008-05-15

    Significant changes in physical and biological systems are occurring on all continents and in most oceans, with a concentration of available data in Europe and North America. Most of these changes are in the direction expected with warming temperature. Here we show that these changes in natural systems since at least 1970 are occurring in regions of observed temperature increases, and that these temperature increases at continental scales cannot be explained by natural climate variations alone. Given the conclusions from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report that most of the observed increase in global average temperatures since the mid-twentieth century is very likely to be due to the observed increase in anthropogenic greenhouse gas concentrations, and furthermore that it is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent except Antarctica, we conclude that anthropogenic climate change is having a significant impact on physical and biological systems globally and in some continents.

  15. Application of phytoextraction for uranium contaminated soil in korea

    NASA Astrophysics Data System (ADS)

    Ryu, Y.; Han, Y.; Lee, M.

    2013-12-01

    The soils having high concentration of uranium, sampled from Goesan Deokpyungri area in Korea, were identified with the uranium removal efficiency of phytoextraction by using several plants. According to the results of physicochemical properties, uranium concentration from soil was 28.85mg/kg, pH 5.43 and soil texture was "Sand". Results of SEP(Sequential Extraction Procedure) test, uranium concentrations ratio of soil in the status of exchangeable/carbonate was 13.4%. Five plants such as Lettuce (Lactuca sativa L.), Chinese cabbage (Brassica campestris L.), Sweet potato (Ipomoea batatas (L.) Lam), Radish (Raphanus sativus), Sesame (Perilla frutescens var. japonica) were cultivated during 56 days in phytotron. All the cultivation processes were conducted in a growth chamber at 25 degrees celsius, 70% relative humidity, 4000 Lux illumination (16 hours/day) and CO2 concentration of 600 ppm. Four times at intervals of 2 weeks leaves and roots collected were analyzed for uranium concentration. Ranges of uranium concentration of the roots and leaves from the five plants were measured to 206.81-721.22μg/kg and 3.45-10.21μg/kg respectively. The majority of uranium was found to accumulate in the roots. Uranium concentration in the leaves, regardless of the type of plants were presented below standard of drinking water(30μg/l) by U.S EPA. Phytoextraction pot experiments with citric acid were conducted. Citric acid as chelating agent was applied to soil to enhance uranium accumulation in five crop plants. 6 days before harvest crops, Each citric acid 25mM and 50mM was injected into the soil by 300ml. After injecting citric acid 25mM , pH of the soil was reduced to 4.95. Uranium concentration of leaves and roots collected from five plants was increased to 2-4times and 7-30times compared to control soil. Injected with citric acid 50mM , pH of the soil was reduced to 4.79. Uranium concentration of leaves and roots collected from five plants was increased to 3-10times and 10

  16. Search for uranium in western United States

    USGS Publications Warehouse

    McKelvey, Vincent Ellis

    1953-01-01

    The search for uranium in the United States is one of the most intensive ever made for any metal during our history. The number of prospectors and miners involved is difficult to estimate but some measure of the size of the effort is indicated by the fact that about 500 geologists are employed by government and industry in the work--more than the total number of geologists engaged in the study of all other minerals together except oil. The largest part of the effort has been concentrated in the western states. No single deposit of major importance by world standards has been discovered but the search has led to the discovery of important minable deposits of carnotite and related minerals on the Colorado Plateau; of large, low grade deposits of uranium in phosphates in the northwestern states and in lignites in the Dakotas, Wyoming, Idaho and New Mexico; and of many new and some promising occurrences of uranium in carnotite-like deposits and in vein deposits. Despite the fact that a large number of the districts considered favorable for the occurrence of uranium have already been examined, the outlook for future discoveries is bright, particularly for uranium in vein and in carnotite-like deposits in the Rocky Mountain States.

  17. Uranium purchases report 1993

    SciTech Connect

    Not Available

    1994-08-10

    Data reported by domestic nuclear utility companies in their responses to the 1991 through 1993 ``Uranium Industry Annual Survey,`` Form EIA-858, Schedule B,`` Uranium Marketing Activities,`` are provided in response to the requirements in the Energy Policy Act 1992. Appendix A contains an explanation of Form EIA-858 survey methodologies with emphasis on the processing of Schedule B data. Additional information published in this report not included in Uranium Purchases Report 1992, includes a new data table. Presented in Table 1 are US utility purchases of uranium and enrichment services by origin country. Also, this report contains additional purchase information covering average price and contract duration. Table 2 is an update of Table 1 and Table 3 is an update of Table 2 from the previous year`s report. The report contains a glossary of terms.

  18. URANIUM RECOVERY PROCESS

    DOEpatents

    Stevenson, J.W.; Werkema, R.G.

    1959-07-28

    The recovery of uranium from magnesium fluoride slag obtained as a by- product in the production of uranium metal by the bomb reduction prccess is presented. Generally the recovery is accomplished by finely grinding the slag, roasting ihe ground slag air, and leaching the roasted slag with a hot, aqueous solution containing an excess of the sodium bicarbonate stoichiometrically required to form soluble uranium carbonate complex. The roasting is preferably carried out at between 425 and 485 deg C for about three hours. The leaching is preferably done at 70 to 90 deg C and under pressure. After leaching and filtration the uranium may be recovered from the clear leach liquor by any desired method.

  19. 300 AREA URANIUM CONTAMINATION

    SciTech Connect

    BORGHESE JV

    2009-07-02

    {sm_bullet} Uranium fuel production {sm_bullet} Test reactor and separations experiments {sm_bullet} Animal and radiobiology experiments conducted at the. 331 Laboratory Complex {sm_bullet} .Deactivation, decontamination, decommissioning,. and demolition of 300 Area facilities

  20. PURIFICATION OF URANIUM FUELS

    DOEpatents

    Niedrach, L.W.; Glamm, A.C.

    1959-09-01

    An electrolytic process of refining or decontaminating uranium is presented. The impure uranium is made the anode of an electrolytic cell. The molten salt electrolyte of this cell comprises a uranium halide such as UF/sub 4/ or UCl/sub 3/ and an alkaline earth metal halide such as CaCl/sub 2/, BaF/sub 2/, or BaCl/sub 2/. The cathode of the cell is a metal such as Mn, Cr, Co, Fe, or Ni which forms a low melting eutectic with U. The cell is operated at a temperature below the melting point of U. In operation the electrodeposited uranium becomes alloyed with the metal of the cathode, and the low melting alloy thus formed drips from the cathode.

  1. Chemical oceanography. Increasing anthropogenic nitrogen in the North Pacific Ocean.

    PubMed

    Kim, Il-Nam; Lee, Kitack; Gruber, Nicolas; Karl, David M; Bullister, John L; Yang, Simon; Kim, Tae-Wook

    2014-11-28

    The recent increase in anthropogenic emissions of reactive nitrogen from northeastern Asia and the subsequent enhanced deposition over the extensive regions of the North Pacific Ocean (NPO) have led to a detectable increase in the nitrate (N) concentration of the upper ocean. The rate of increase of excess N relative to phosphate (P) was found to be highest (~0.24 micromoles per kilogram per year) in the vicinity of the Asian source continent, with rates decreasing eastward across the NPO, consistent with the magnitude and distribution of atmospheric nitrogen deposition. This anthropogenically driven increase in the N content of the upper NPO may enhance primary production in this N-limited region, potentially leading to a long-term change of the NPO from being N-limited to P-limited.

  2. Chemical oceanography. Increasing anthropogenic nitrogen in the North Pacific Ocean.

    PubMed

    Kim, Il-Nam; Lee, Kitack; Gruber, Nicolas; Karl, David M; Bullister, John L; Yang, Simon; Kim, Tae-Wook

    2014-11-28

    The recent increase in anthropogenic emissions of reactive nitrogen from northeastern Asia and the subsequent enhanced deposition over the extensive regions of the North Pacific Ocean (NPO) have led to a detectable increase in the nitrate (N) concentration of the upper ocean. The rate of increase of excess N relative to phosphate (P) was found to be highest (~0.24 micromoles per kilogram per year) in the vicinity of the Asian source continent, with rates decreasing eastward across the NPO, consistent with the magnitude and distribution of atmospheric nitrogen deposition. This anthropogenically driven increase in the N content of the upper NPO may enhance primary production in this N-limited region, potentially leading to a long-term change of the NPO from being N-limited to P-limited. PMID:25430767

  3. Increasing anthropogenic nitrogen in the North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Kim, Il-Nam; Lee, Kitack; Gruber, Nicolas; Karl, David M.; Bullister, John L.; Yang, Simon; Kim, Tae-Wook

    2014-11-01

    The recent increase in anthropogenic emissions of reactive nitrogen from northeastern Asia and the subsequent enhanced deposition over the extensive regions of the North Pacific Ocean (NPO) have led to a detectable increase in the nitrate (N) concentration of the upper ocean. The rate of increase of excess N relative to phosphate (P) was found to be highest (∼0.24 micromoles per kilogram per year) in the vicinity of the Asian source continent, with rates decreasing eastward across the NPO, consistent with the magnitude and distribution of atmospheric nitrogen deposition. This anthropogenically driven increase in the N content of the upper NPO may enhance primary production in this N-limited region, potentially leading to a long-term change of the NPO from being N-limited to P-limited.

  4. National uranium resource evaluation, Marble Canyon Quadrangle, Arizona and Utah

    SciTech Connect

    Field, M T; Blauvelt, R P

    1982-05-01

    The Marble Canyon Quadrangle (2/sup 0/), northeast Arizona, was evaluated to a depth of 1500 m for uranium favorability using National Uranium Resource Evaluation criteria. Known mines and prospects were examined; field reconnaissance was done in selected areas of the quadrangle; and a ground-water geochemical survey was made in the southeast third of the quadrangle. The Shinarump and Petrified Forest Members of the Triassic Chinle Formation, which is exposed in the western and northeastern parts of the quadrangle and is present beneath the surface of much of the quadrangle, were found favorable for channel-sandstone uranium deposits. A portion of the Cretaceous Toreva Formation in the southeast part of the quadrangle was found favorable for peneconcordant-sandstone uranium deposits. The western part of the quadrangle was found favorable for uranium concentrations in breccia pipes.

  5. URANIUM EXTRACTION PROCESS

    DOEpatents

    Baldwin, W.H.; Higgins, C.E.

    1958-12-16

    A process is described for recovering uranium values from acidic aqueous solutions containing hexavalent uranium by contacting the solution with an organic solution comprised of a substantially water-immiscible organlc diluent and an organic phosphate to extract the uranlum values into the organic phase. Carbon tetrachloride and a petroleum hydrocarbon fraction, such as kerosene, are sultable diluents to be used in combination with organlc phosphates such as dibutyl butylphosphonate, trlbutyl phosphine oxide, and tributyl phosphate.

  6. ANODIC TREATMENT OF URANIUM

    DOEpatents

    Kolodney, M.

    1959-02-01

    A method is presented for effecting eloctrolytic dissolution of a metallic uranium article at a uniform rate. The uranium is made the anode in an aqueous phosphoric acid solution containing nitrate ions furnished by either ammonium nitrate, lithium nitrate, sodium nitrate, or potassium nitrate. A stainless steel cathode is employed and electrolysls carried out at a current density of about 0.1 to 1 ampere per square inch.

  7. URANIUM SEPARATION PROCESS

    DOEpatents

    Lyon, W.L.

    1962-04-17

    A method of separating uranium oxides from PuO/sub 2/, ThO/sub 2/, and other actinide oxides is described. The oxide mixture is suspended in a fused salt melt and a chlorinating agent such as chlorine gas or phosgene is sparged through the suspension. Uranium oxides are selectively chlorinated and dissolve in the melt, which may then be filtered to remove the unchlorinated oxides of the other actinides. (AEC)

  8. Tuffaceous sediments as source rocks for uranium: A case study of the White River Formation, Wyoming

    USGS Publications Warehouse

    Zielinski, R.A.

    1983-01-01

    Fine-grained tuffaceous sediments of the White River Formation (Oligocene) are evaluated as a possible source of uranium for the sedimentary uranium deposits of Wyoming. The evaluation is based upon a model in which volcanic glass is considered to be a major host of uranium and thorium and in which uranium and silica are released during alteration of glass to montmorillonite. The evaluation scheme is applicable to other tuffaceous sediments in similar geologic settings. The average uranium and thorium contents of glass separates and glassy air-fall ashes of the White River Formation are 8 ppm and 22.4 ppm respectively, and these values approximate the average composition of glass deposited in Wyoming basins in Oligocene time. Comparison of these values with the uranium and thorium concentrations in montmorillonite separates indicates little change in thorium concentrations but reductions in uranium concentrations which average 3.3 ppm. In spite of the apparent major removal of uranium during alteration of glass to montmorillonite, whole-rock samples of tuffaceous siltstones show an average uranium loss of only 0.4 ?? 0.4 ppm, because of generally small amounts of clay alteration. This conclusion is generated by comparisons between glassy ash and partially altered vitric siltstones, the latter corrected for dilution of glass and clay-altered glass with uranium- and thorium-poor primary and detrital materials. The original volume of the White River Formation is adequate to generate economically significant quantities of mobile uranium, even with such modest losses. Uranium and silica which are mobilized during glass alteration can coprecipitate as uraniferous secondary silica in areas where solutions become silica saturated. These precipitates indicate pathways of ancient, uranium-rich solutions in tuffaceous rocks. Exploration efforts in the White River Formation and underlying units should concentrate on areas where such pathways intercept reducing environments

  9. Method for the recovery of uranium values from uranium tetrafluoride

    DOEpatents

    Kreuzmann, A.B.

    1982-10-27

    The invention is a novel method for the recovery of uranium from dry, particulate uranium tetrafluoride. In one aspect, the invention comprises reacting particulate uranium tetrafluoride and calcium oxide in the presence of gaseous oxygen to effect formation of the corresponding alkaline earth metal uranate and alkaline earth metal fluoride. The product uranate is highly soluble in various acidic solutions whereas the product fluoride is virtually insoluble therein. The product mixture of uranate and alkaline earth metal fluoride is contacted with a suitable acid to provide a uranium-containing solution, from which the uranium is recovered. The invention can achieve quantitative recovery of uranium in highly pure form.

  10. Method for the recovery of uranium values from uranium tetrafluoride

    DOEpatents

    Kreuzmann, Alvin B.

    1983-01-01

    The invention is a novel method for the recovery of uranium from dry, particulate uranium tetrafluoride. In one aspect, the invention comprises reacting particulate uranium tetrafluoride and calcium oxide in the presence of gaseous oxygen to effect formation of the corresponding alkaline earth metal uranate and alkaline earth metal fluoride. The product uranate is highly soluble in various acidic solutions wherein the product fluoride is virtually insoluble therein. The product mixture of uranate and alkaline earth metal fluoride is contacted with a suitable acid to provide a uranium-containing solution, from which the uranium is recovered. The invention can achieve quantitative recovery of uranium in highly pure form.

  11. Dissolution of uranium oxides from simulated environmental swipes using ammonium bifluoride

    DOE PAGESBeta

    Meyers, Lisa A.; Yoshida, Thomas M.; Chamberlin, Rebecca M.; Xu, Ning

    2016-04-09

    We developed an analytical chemistry method to quantitatively recover microgram quanties of solid uranium oxides from swipe media using ammonium bifluoride (ABF, NH4HF2) solution. Recovery of uranium from surrogate swipe media (filter paper) was demonstrated at initial uranium loading levels between 3 and 20 µg filter-1. Moreover, the optimal conditions for extracting U3O8 and UO2 are using 1 % ABF solution and incubating at 80 °C for one hour. The average uranium recoveries are 100 % for U3O8, and 90 % for UO2. Finally, with this method, uranium concentration as low as 3 µg filter-1 can be recovered for analysis.

  12. Translocation of uranium from water to foodstuff while cooking.

    PubMed

    Krishnapriya, K C; Baksi, Ananya; Chaudhari, Swathi; Gupta, Soujit Sen; Pradeep, T

    2015-10-30

    The present work report the unusual uranium uptake by foodstuff, especially those rich in carbohydrates like rice when they are cooked in water, contaminated with uranium. The major staple diet in South Asia, rice, was chosen to study its interaction with UO2(2+), the active uranium species in water, using inductively coupled plasma mass spectrometry. Highest uptake limit was checked by cooking rice at very high uranium concentration and it was found to be good scavenger of uranium. To gain insight into the mechanism of uptake, direct interaction of UO2(2+) with monosaccharides was also studied, using electrospray ionization mass spectrometry taking mannose as a model. The studies have been done with dissolved uranium salt, uranyl nitrate hexahydrate (UO2(NO3)2·6H2O), as well as the leachate of a stable oxide of uranium, UO2(s), both of which exist as UO2(2+) in water. Among the eight different rice varieties investigated, Karnataka Ponni showed the maximum uranium uptake whereas unpolished Basmati rice showed the minimum. Interaction with other foodstuffs (potato, carrot, peas, kidney beans and lentils) with and without NaCl affected the extent of chemical interaction but was not consistent with the carbohydrate content. Uranium interaction with D-mannose monitored through ESI-MS, under optimized instrumental parameters, identified the peaks corresponding to uranyl adduct with mannose monomer, dimer and trimer and the species were confirmed by MS/MS studies. The product ion mass spectra showed peaks illustrating water loss from the parent ion as the collision energy was increased, an evidence for the strong interaction of uranium with mannose. This study would constitute the essential background for understanding interaction of uranium with various foods. Extension of this work would involve identification of foodstuff as green heavy metal scavengers. PMID:25956648

  13. Translocation of uranium from water to foodstuff while cooking.

    PubMed

    Krishnapriya, K C; Baksi, Ananya; Chaudhari, Swathi; Gupta, Soujit Sen; Pradeep, T

    2015-10-30

    The present work report the unusual uranium uptake by foodstuff, especially those rich in carbohydrates like rice when they are cooked in water, contaminated with uranium. The major staple diet in South Asia, rice, was chosen to study its interaction with UO2(2+), the active uranium species in water, using inductively coupled plasma mass spectrometry. Highest uptake limit was checked by cooking rice at very high uranium concentration and it was found to be good scavenger of uranium. To gain insight into the mechanism of uptake, direct interaction of UO2(2+) with monosaccharides was also studied, using electrospray ionization mass spectrometry taking mannose as a model. The studies have been done with dissolved uranium salt, uranyl nitrate hexahydrate (UO2(NO3)2·6H2O), as well as the leachate of a stable oxide of uranium, UO2(s), both of which exist as UO2(2+) in water. Among the eight different rice varieties investigated, Karnataka Ponni showed the maximum uranium uptake whereas unpolished Basmati rice showed the minimum. Interaction with other foodstuffs (potato, carrot, peas, kidney beans and lentils) with and without NaCl affected the extent of chemical interaction but was not consistent with the carbohydrate content. Uranium interaction with D-mannose monitored through ESI-MS, under optimized instrumental parameters, identified the peaks corresponding to uranyl adduct with mannose monomer, dimer and trimer and the species were confirmed by MS/MS studies. The product ion mass spectra showed peaks illustrating water loss from the parent ion as the collision energy was increased, an evidence for the strong interaction of uranium with mannose. This study would constitute the essential background for understanding interaction of uranium with various foods. Extension of this work would involve identification of foodstuff as green heavy metal scavengers.

  14. Continental anthropogenic primary particle number emissions

    NASA Astrophysics Data System (ADS)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  15. Pribram uranium district

    SciTech Connect

    1990-11-01

    Pribram is one of the largest and richest vein uranium districts in the world. The Pribram district has accounted for about 60 percent of Czechoslovakia`s total uranium production. The Pribram uranium district is located about 60 kilometers southwest of Prague, in Cezechslovakia`s central Bohemia region. This district contains perigranitic, monometallic, vein-type uranium deposits. The deposits are within a northeast-southwest elongated area, about 20 kilometers long and 1-2 kilometers wide, located between Oboriste in the northeast and Tresko in the southwest. Several thousand veins have been discovered; about 1,600 have been mined. Most of the veins are grouped in clusters, which are intense accumulations of veins paralleling or intersecting each other within a narrow segment. Until this year, all uranium production was exported to the USSR, with only the amount required for Czechoslovakia`s nuclear power stations being returned (as fabricated fuel). Most of Czechoslovakia`s present and future uranium production will come from sandstone deposits in the North Bohemian Cretaceous Basin, such as Hamr and Straz.

  16. 300 Area Uranium Stabilization Through Polyphosphate Injection: Final Report

    SciTech Connect

    Vermeul, Vincent R.; Bjornstad, Bruce N.; Fritz, Brad G.; Fruchter, Jonathan S.; Mackley, Rob D.; Newcomer, Darrell R.; Mendoza, Donaldo P.; Rockhold, Mark L.; Wellman, Dawn M.; Williams, Mark D.

    2009-06-30

    The objective of the treatability test was to evaluate the efficacy of using polyphosphate injections to treat uranium-contaminated groundwater in situ. A test site consisting of an injection well and 15 monitoring wells was installed in the 300 Area near the process trenches that had previously received uranium-bearing effluents. This report summarizes the work on the polyphosphate injection project, including bench-scale laboratory studies, a field injection test, and the subsequent analysis and interpretation of the results. Previous laboratory tests have demonstrated that when a soluble form of polyphosphate is injected into uranium-bearing saturated porous media, immobilization of uranium occurs due to formation of an insoluble uranyl phosphate, autunite [Ca(UO2)2(PO4)2•nH2O]. These tests were conducted at conditions expected for the aquifer and used Hanford soils and groundwater containing very low concentrations of uranium (10-6 M). Because autunite sequesters uranium in the oxidized form U(VI) rather than forcing reduction to U(IV), the possibility of re-oxidation and subsequent re-mobilization is negated. Extensive testing demonstrated the very low solubility and slow dissolution kinetics of autunite. In addition to autunite, excess phosphorous may result in apatite mineral formation, which provides a long-term source of treatment capacity. Phosphate arrival response data indicate that, under site conditions, the polyphosphate amendment could be effectively distributed over a relatively large lateral extent, with wells located at a radial distance of 23 m (75 ft) reaching from between 40% and 60% of the injection concentration. Given these phosphate transport characteristics, direct treatment of uranium through the formation of uranyl-phosphate mineral phases (i.e., autunite) could likely be effectively implemented at full field scale. However, formation of calcium-phosphate mineral phases using the selected three-phase approach was problematic. Although

  17. Occurrence of Metastudtite (Uranium Peroxide Dihydrate) at a FUSRAP Site

    SciTech Connect

    Young, C.M.; Nelson, K.A.; Stevens, G.T.; Grassi, V.J.

    2006-07-01

    Uranium concentrations in groundwater in a localized area of a site exceed the USEPA Maximum Contaminant Level (MCL) by a factor of one thousand. Although the groundwater seepage velocity ranges up to 0.7 meters per day (m/day), data indicate that the uranium is not migrating in groundwater. We believe that the uranium is not mobile because of local geochemical conditions and the unstable nature of the uranium compound present at the site; uranium peroxide dihydrate (metastudtite). Metastudtite [UO{sub 4}.2(H{sub 2}O) or (U(O{sub 2})|O|(OH){sub 2}).3H{sub 2}O] has been identified at other sites as an alteration product in casks of spent nuclear fuel, but neither enriched nor depleted uranium were present at this site. Metastudtite was first identified as a natural mineral in 1983, although documented occurrences in the environment are uncommon. The U.S. Army Corps of Engineers (USACE) is conducting a remedial investigation at the DuPont Chambers Works in Deep water New Jersey under the Formerly Utilized Sites Remedial Action Program (FUSRAP) to evaluate radioactive contamination resulting from historical activities conducted in support of Manhattan Engineering District operations. From 1942 to 1947, Chambers Works converted uranium oxides to uranium tetrafluoride and uranium metal. More than half of the production at this facility resulted from the recovery process, where uranium-bearing dross and scrap were reacted with hydrogen peroxide to produce uranium peroxide dihydrate. The 280-hectare Chambers Works has produced some 600 products, including petrochemicals, aromatics, fluoro-chemicals, polymers, and elastomers. Contaminants resulting from these processes, including separate-phase petrochemicals, have also been detected within the boundaries of the FUSRAP investigation. USACE initiated remedial investigation field activities in 2002. The radionuclides of concern are natural uranium (U{sub nat}) and its short-lived progeny. Areas of impacted soil generally

  18. Geochemical characteristics of the Church Rock 1 and 1 East uranium deposits, Grants uranium region, New Mexico

    USGS Publications Warehouse

    Fishman, Neil S.; Reynolds, Richard L.

    1983-01-01

    In the Church Rock 1 and 1 East mines, Grants uranium region (GUR), New Mexico, uranium orebodies occur within three sandstone units in the upper part of the Westwater Canyon Member of the late Jurassic Morrison Formation. Geochemical analyses reveal that organic carbon contents in ore samples from all three sand units are uniformly low (most are less than 0.01 percent). Vanadium (ranging from 0.0002 to 0.19 percent) and sulfur (ranging from <0.01 to 0.74 percent) typically show positive correlations with uranium; however, vanadium contents rarely exceed those of uranium in ore samples. Although no systematic relationship of either selenium or molybdenum to uranium is evident, some ore samples contain anomalously high concentrations of either of these elements. Geochemically, the ore deposits of the Church Rock area contrast greatly with primary (tabular) uranium orebodies in the GUR which contain abundant organic carbon and greater amounts of vanadium and sulfur. These differences and radiometric age determinations strongly suggest that the Church Rock ores formed as a result of the redistribution of uranium from preexisting uranium deposits within the last 1 m.y. However, the Church Rock deposits differ geochemically from redistributed orebodies in the Westwater Canyon Member elsewhere in the GUR. Specifically, redistributed orebodies in the Ambrosia Lake district, which are comparable in contents of uranium and organic carbon with the Church Rock deposits, are characterized by vanadium contents typically higher than those of uranium. Similarly, sulfur contents in the redistributed deposits of the Ambrosia Lake district are greater than those found in the Church Rock ores. In addition, anomalously high concentrations of molybdenum have rarely been found in other redistributed orebodies of the GUR.

  19. Late Holocene climate: Natural or anthropogenic?

    NASA Astrophysics Data System (ADS)

    Ruddiman, W. F.; Fuller, D. Q.; Kutzbach, J. E.; Tzedakis, P. C.; Kaplan, J. O.; Ellis, E. C.; Vavrus, S. J.; Roberts, C. N.; Fyfe, R.; He, F.; Lemmen, C.; Woodbridge, J.

    2016-03-01

    For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2.

  20. Occurrence of uranium in Swiss drinking water.

    PubMed

    Stalder, E; Blanc, A; Haldimann, M; Dudler, V

    2012-02-01

    The results of a nationwide survey of uranium in Swiss drinking water are reported. Elevated concentrations of uranium in groundwater are found mainly in the alpine regions and can be traced back to the geology of the bedrock. Water sources were systematically surveyed and analysed for the presence of Li, B, Si, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Sn, Sb, Ba, Tl, Pb and U and the results were analysed to determine if any correlation with uranium concentration was apparent. No correlation was found. The results are interpreted in relation to the current WHO guideline and those of other countries with a view to determining which areas would be affected if a maximum value were to be adopted and which areas require further investigation. Uranium content varied considerably, from below the limit of detection to almost 100 μg L(-1). Of the 5548 data samples, 98% are below the 2004 WHO provisional guideline value of 15 μg L(-1) and 99.7% below the revised (2011) value of 30 μg L(-1).

  1. Uranium incorporation into amorphous silica.

    PubMed

    Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

    2014-01-01

    High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ∼ 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ∼ 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ∼ 3.1-3.2 Å, U at ∼ 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination. PMID:24984107

  2. Characterization and remediation of soils contaminated with uranium.

    PubMed

    Gavrilescu, Maria; Pavel, Lucian Vasile; Cretescu, Igor

    2009-04-30

    Environmental contamination caused by radionuclides, in particular by uranium and its decay products is a serious problem worldwide. The development of nuclear science and technology has led to increasing nuclear waste containing uranium being released and disposed in the environment. The objective of this paper is to develop a better understanding of the techniques for the remediation of soils polluted with radionuclides (uranium in particular), considering: the chemical forms of uranium, including depleted uranium (DU) in soil and other environmental media, their characteristics and concentrations, and some of the effects on environmental and human health; research issues concerning the remediation process, the benefits and results; a better understanding of the range of uses and situations for which each is most appropriate. The paper addresses the main features of the following techniques for uranium remediation: natural attenuation, physical methods, chemical processes (chemical extraction methods from contaminated soils assisted by various suitable chelators (sodium bicarbonate, citric acid, two-stage acid leaching procedure), extraction using supercritical fluids such as solvents, permeable reactive barriers), biological processes (biomineralization and microbial reduction, phytoremediation, biosorption), and electrokinetic methods. In addition, factors affecting uranium removal from soils are furthermore reviewed including soil characteristics, pH and reagent concentration, retention time.

  3. Process for electrolytically preparing uranium metal

    DOEpatents

    Haas, Paul A.

    1989-01-01

    A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

  4. Process for electrolytically preparing uranium metal

    DOEpatents

    Haas, Paul A.

    1989-08-01

    A process for making uranium metal from uranium oxide by first fluorinating uranium oxide to form uranium tetrafluoride and next electrolytically reducing the uranium tetrafluoride with a carbon anode to form uranium metal and CF.sub.4. The CF.sub.4 is reused in the fluorination reaction rather than being disposed of as a hazardous waste.

  5. Influence of uranium hydride oxidation on uranium metal behaviour

    SciTech Connect

    Patel, N.; Hambley, D.; Clarke, S.A.; Simpson, K.

    2013-07-01

    This work addresses concerns that the rapid, exothermic oxidation of active uranium hydride in air could stimulate an exothermic reaction (burning) involving any adjacent uranium metal, so as to increase the potential hazard arising from a hydride reaction. The effect of the thermal reaction of active uranium hydride, especially in contact with uranium metal, does not increase in proportion with hydride mass, particularly when considering large quantities of hydride. Whether uranium metal continues to burn in the long term is a function of the uranium metal and its surroundings. The source of the initial heat input to the uranium, if sufficient to cause ignition, is not important. Sustained burning of uranium requires the rate of heat generation to be sufficient to offset the total rate of heat loss so as to maintain an elevated temperature. For dense uranium, this is very difficult to achieve in naturally occurring circumstances. Areas of the uranium surface can lose heat but not generate heat. Heat can be lost by conduction, through contact with other materials, and by convection and radiation, e.g. from areas where the uranium surface is covered with a layer of oxidised material, such as burned-out hydride or from fuel cladding. These rates of heat loss are highly significant in relation to the rate of heat generation by sustained oxidation of uranium in air. Finite volume modelling has been used to examine the behaviour of a magnesium-clad uranium metal fuel element within a bottle surrounded by other un-bottled fuel elements. In the event that the bottle is breached, suddenly, in air, it can be concluded that the bulk uranium metal oxidation reaction will not reach a self-sustaining level and the mass of uranium oxidised will likely to be small in relation to mass of uranium hydride oxidised. (authors)

  6. The absorption spectra of the complexes of uranium (VI) with some β-diketones

    USGS Publications Warehouse

    Feinstein, H.I.

    1956-01-01

    The absorption spectra of the complexes of uranium (VI) with four β-dike tones were determined under various conditions of pH, concentration of uranium, and alcohol concentration. Under optimum conditions, the maximum molar absorptivity (31,200) is obtained using 2-furoyltrifluoroacetone. This compares with about 4,000 and 19,000 for the thiocyanate and dibenzoylmethane complexes, respectively.

  7. Semi-automated potentiometric titration method for uranium characterization.

    PubMed

    Cristiano, B F G; Delgado, J U; da Silva, J W S; de Barros, P D; de Araújo, R M S; Lopes, R T

    2012-07-01

    The manual version of the potentiometric titration method has been used for certification and characterization of uranium compounds. In order to reduce the analysis time and the influence of the analyst, a semi-automatic version of the method was developed in the Brazilian Nuclear Energy Commission. The method was applied with traceability assured by using a potassium dichromate primary standard. The combined standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization. PMID:22154105

  8. Laser ablation inductively coupled plasma mass spectrometry measurement of isotope ratios in depleted uranium contaminated soils.

    PubMed

    Seltzer, Michael D

    2003-09-01

    Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma.

  9. Laser ablation inductively coupled plasma mass spectrometry measurement of isotope ratios in depleted uranium contaminated soils.

    PubMed

    Seltzer, Michael D

    2003-09-01

    Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma. PMID:14611049

  10. Uranium deposits of Brazil

    SciTech Connect

    1991-09-01

    Brazil is a country of vast natural resources, including numerous uranium deposits. In support of the country`s nuclear power program, Brazil has developed the most active uranium industry in South America. Brazil has one operating reactor (Angra 1, a 626-MWe PWR), and two under construction. The country`s economic challenges have slowed the progress of its nuclear program. At present, the Pocos de Caldas district is the only active uranium production. In 1990, the Cercado open-pit mine produced approximately 45 metric tons (MT) U{sub 3}O{sub 8} (100 thousand pounds). Brazil`s state-owned uranium production and processing company, Uranio do Brasil, announced it has decided to begin shifting its production from the high-cost and nearly depleted deposits at Pocos de Caldas, to lower-cost reserves at Lagoa Real. Production at Lagoa Real is schedules to begin by 1993. In addition to these two districts, Brazil has many other known uranium deposits, and as a whole, it is estimated that Brazil has over 275,000 MT U{sub 3}O{sub 8} (600 million pounds U{sub 3}O{sub 8}) in reserves.

  11. Microbial reduction of uranium

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.; Gorby, Y.A.; Landa, E.R.

    1991-01-01

    REDUCTION of the soluble, oxidized form of uranium, U(VI), to insoluble U(IV) is an important mechanism for the immobilization of uranium in aquatic sediments and for the formation of some uranium ores1-10. U(VI) reduction has generally been regarded as an abiological reaction in which sulphide, molecular hydrogen or organic compounds function as the reductant1,2,5,11. Microbial involvement in U(VI) reduction has been considered to be limited to indirect effects, such as microbial metabolism providing the reduced compounds for abiological U(VI) reduction and microbial cell walls providing a surface to stimulate abiological U(VI) reduction1,12,13. We report here, however, that dissimilatory Fe(III)-reducing microorganisms can obtain energy for growth by electron transport to U(VI). This novel form of microbial metabolism can be much faster than commonly cited abiological mechanisms for U(VI) reduction. Not only do these findings expand the known potential terminal electron acceptors for microbial energy transduction, they offer a likely explanation for the deposition of uranium in aquatic sediments and aquifers, and suggest a method for biological remediation of environments contaminated with uranium.

  12. PRODUCTION OF URANIUM HEXAFLUORIDE

    DOEpatents

    Fowler, R.D.

    1957-08-27

    A process for the production of uranium hexafluoride from the oxides of uranium is reported. In accordance with the method, the higher oxides of uranium may be reduced to uranium dioxide (UO/sub 2/), the latter converted into uranium tetrafluoride by reaction with hydrogen fluoride, and the UF/sub 4/ converted to UF/sub 6/ by reaction with a fluorinating agent, such as CoF/sub 3/. The UO/sub 3/ or U/sub 3/O/sub 8/ is placed in a reac tion chamber in a copper boat or tray enclosed in a copper oven, and heated to 500 to 650 deg C while hydrogen gas is passed through the oven. After nitrogen gas is used to sweep out the hydrogen and the water vapor formed, and while continuing to inaintain the temperature between 400 deg C and 600 deg C, anhydrous hydrogen fluoride is passed through. After completion of the conversion of UO/sub 2/ to UF/sub 4/ the temperature of the reaction chamber is lowered to about 400 deg C or less, the UF/sub 4/ is mixed with the requisite quantity of CoF/sub 3/, and after evacuating the chamber, the mixture is heated to 300 to 400 deg C, and the resulting UF/sub 6/ is led off and delivered to a condenser.

  13. Uranium hexafluoride handling. Proceedings

    SciTech Connect

    Not Available

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

  14. Uranium resources: Issues and facts

    SciTech Connect

    Delene, J.G.

    1993-12-31

    Although there are several secondary issues, the most important uranium resource issue is, ``will there be enough uranium available at a cost which will allow nuclear power to be competitive in the future?`` This paper will attempt to answer this question by discussing uranium supply, demand, and economics from the perspective of the United States. The paper will discuss: how much uranium is available; the sensitivity of nuclear power costs to uranium price; the potential future demand for uranium in the Unites States, some of the options available to reduce this demand, the potential role of the Advanced Liquid Metal Cooled Reactor (ALMR) in reducing uranium demand; and potential alternative uranium sources and technologies.

  15. METHOD OF RECOVERING URANIUM COMPOUNDS

    DOEpatents

    Poirier, R.H.

    1957-10-29

    S>The recovery of uranium compounds which have been adsorbed on anion exchange resins is discussed. The uranium and thorium-containing residues from monazite processed by alkali hydroxide are separated from solution, and leached with an alkali metal carbonate solution, whereby the uranium and thorium hydrorides are dissolved. The carbonate solution is then passed over an anion exchange resin causing the uranium to be adsorbed while the thorium remains in solution. The uranium may be recovered by contacting the uranium-holding resin with an aqueous ammonium carbonate solution whereby the uranium values are eluted from the resin and then heating the eluate whereby carbon dioxide and ammonia are given off, the pH value of the solution is lowered, and the uranium is precipitated.

  16. Experiments and Modeling of Uranium Adsorption in the Presence of Other Ions in Simulated Seawater

    SciTech Connect

    Ladshaw, Austin; Das, Sadananda; Liao, Wei-Po; Yiacoumi, Sotira; Janke, Christopher James; Mayes, Richard T.; Dai, Sheng; Tsouris, Costas

    2015-11-19

    Seawater contains uranium at an average concentration of 3.3 ppb, as well as a variety of other ions at either overwhelmingly higher or similar concentrations, which complicate the recovery of uranium. This report describes an investigation of the effects of various factors such as uranium speciation and presence of salts including sodium, calcium, magnesium, and bicarbonate, as well as trace elements such as vanadium on uranium adsorption kinetics in laboratory experiments. Adsorption models are also developed to describe the experimental data of uranium extraction from seawater. Results show that the presence of calcium and magnesium significantly slows down the uranium adsorption kinetics. Vanadium can replace uranium from amidoxime-based adsorbent in the presence of sodium in the solution. Results also show that bicarbonate in the solution strongly competes with amidoxime for binding uranium, and thus slows down the uranium adsorption kinetics. Developed on the basis of the experimental findings, the model is capable of describing the effects of pH, ionic strength, temperature, and concentration of various species. The results of this work are useful in the understanding of the important factors that control the adsorbent capacity and kinetics of uranium uptake by amidoxime-based adsorbents.

  17. The Anthropogenic Era Began Thousands of Years Ago

    NASA Astrophysics Data System (ADS)

    Ruddiman, W. F.

    2003-12-01

    The anthropogenic era is generally thought to have begun about 150 years ago when the industrial revolution began producing CO2 and CH4 at rates sufficient to alter atmospheric compositions. The hypothesis proposed here is that anthropogenic emissions first altered atmospheric gas concentrations (and climate) thousands of years ago. This hypothesis rests on three arguments: (1) Cyclic variations in CO2 and CH4 driven by Earth-orbital changes during the last 400,000 years predict decreases of both gases throughout the Holocene, but CO2 began an anomalous increase near 8000 years ago and CH4 about 5000 years ago. (2) Published explanations attributing these Holocene gas increases to natural forcing can be rejected based on available paleoclimatic evidence. (3) Archeological, cultural, historical, and geologic sources provide viable explanations tied to anthropogenic changes that emerged from early agriculture in Eurasia, including forest clearance after 8000 years ago and lowland irrigation for rice farming by 5000 years ago. Prior to the industrial era, these emissions caused a mean-annual warming effect of ~0.8oC globally and 1.5-2oC at high latitudes. The early-anthropogenic warming counteracted most of a natural cooling that would otherwise have occurred, and it may have prevented a glaciation in northeastern Canada predicted by two kinds of climatic models. CO2 decreases as large as 10 ppm during the last 1000 years cannot be explained by solar-volcanic forcing without violating constraints imposed by reconstructions of northern hemisphere temperature. The CO2 decreases can be explained by bubonic plague pandemics that the caused widespread abandonment of western Eurasian farms documented in historical records. Rapid regrowth of forests on millions of abandoned farms could have sequestered enough carbon to explain the observed CO2 decreases. Plague-driven CO2 decreases were a significant causal factor in the cooler temperatures of the Little Ice Age from 1300 to

  18. Contribution of Natural and Anthropogenic Emissions to Smog in Bogotá

    NASA Astrophysics Data System (ADS)

    Henderson, B. H.

    2015-12-01

    Bogotá Colombia is an emerging mega-city whose geographic orientation creates an interesting dynamic between regional biogenic and local anthropogenic emissions. Bogotá's metropolitan area has over 13 million inhabitants all above 2,600 meters, where the anthropogenic emissions are concentrated. Because of the high elevation, density of development, and low temperatures, the local biogenic emissions are relatively small contributors to the total VOC. The surrounding area has a much lower altitude and over 5 times higher average biogenic emission fluxes. This work characterizes the interaction between local anthropogenic emissions and surrounding biogenic emissions. The simulated photochemical environment shows clear urban/rural interfaces. Ozone concentrations are higher in the surrounding region and show titration around the boundary of Bogotá. We use chemical indicators to define the identify the extent of interaction and apportion ozone and photochemically produced secondary aerosols. We also examine the roles of proposed regulation on interaction between biogenic and anthropogenic emissions. In Bogotá local and regional emissions exert clearly distinct influences, but also interesting confluences. The combination of regional biogenic emissions and local anthropogenic emissions creates an ideal case study for biogenic/anthropogenic interaction. Our results show strong NOx inhibition now that must be considered in the future. We also show that secondary aerosols from biogenic sources are also inhibited in our modeling system.

  19. Identification and quantification of the source terms for uranium in surface waters collected at the Rocky Flats facility

    NASA Astrophysics Data System (ADS)

    Efurd, D. W.; Rokop, D. J.; Aguilar, R. D.; Roensch, F. R.; Banar, J. C.; Perrin, R. E.

    1995-08-01

    The intent of this study was to determine the fraction of soluble uranium attributable to the Rocky Flats Plant (RFP) operations which is recoverable from waters and suspended sediments drawn from ponds on site at RFP. Samples were collected from late 1992 through 1993. Thermal ionization mass spectrometry (TIMS) measurement techniques indicate that the water samples contain both naturally occurring uranium and depleted uranium. The uranium concentrations in the waters collected from the terminal ponds contained 0.5% or less of the interim standard calculated derived concentration guide for uranium in waters available to the public.

  20. Atmospheric carbonyl sulfide sources from anthropogenic activity: Implications for carbon cycle constraints

    SciTech Connect

    Campbell, Elliott; Whelan, Mary; Seibt, U.; Smith, Steven J.; Berry, Joe; Hilton, Timothy W.

    2015-04-28

    Carbonyl sulfide (COS) has recently emerged as an atmospheric tracer of gross primary production. All modeling studies of COS air-monitoring data rely on a climatological anthropogenic inventory that does not reflect present conditions or support interpretation of ice core and firn trends. Here we develop a global anthropogenic inventory for the years 1850 to 2013 based on new emission measurements and material-specific data. By applying methods from a recent regional inventory to global data, we find that the anthropogenic source is similar in magnitude to the plant sink, confounding carbon cycle applications. However, a material-specific approach results in a current anthropogenic source that is only one-third of plant uptake and is concentrated in Asia, supporting carbon cycle applications of global air-monitoring data. Furthermore, the source alone cannot explain the century-scale mixing ratio growth, which suggests that ice and firn data may provide the first global history of gross primary production.

  1. Removal of fluoride and uranium by nanofiltration and reverse osmosis: a review.

    PubMed

    Shen, Junjie; Schäfer, Andrea

    2014-12-01

    Inorganic contamination in drinking water, especially fluoride and uranium, has been recognized as a worldwide problem imposing a serious threat to human health. Among several treatment technologies applied for fluoride and uranium removal, nanofiltration (NF) and reverse osmosis (RO) have been studied extensively and proven to offer satisfactory results with high selectivity. In this review, a comprehensive summary and critical analysis of previous NF and RO applications on fluoride and uranium removal is presented. Fluoride retention is generally governed by size exclusion and charge interaction, while uranium retention is strongly affected by the speciation of uranium and size exclusion usually plays a predominant role for all species. Adsorption on the membrane occurs as some uranium species interact with membrane functional groups. The influence of operating conditions (pressure, crossflow velocity), water quality (concentration, solution pH), solute–solute interactions, membrane characteristics and membrane fouling on fluoride and uranium retention is critically reviewed.

  2. Decommissioning of U.S. uranium production facilities

    SciTech Connect

    Not Available

    1995-02-01

    From 1980 to 1993, the domestic production of uranium declined from almost 44 million pounds U{sub 3}O{sub 8} to about 3 million pounds. This retrenchment of the U.S. uranium industry resulted in the permanent closing of many uranium-producing facilities. Current low uranium prices, excess world supply, and low expectations for future uranium demand indicate that it is unlikely existing plants will be reopened. Because of this situation, these facilities eventually will have to be decommissioned. The Uranium Mill Tailings and Radiation Control Act of 1978 (UMTRCA) vests the U.S. Environmental Protection Agency (EPA) with overall responsibility for establishing environmental standards for decommissioning of uranium production facilities. UMTRCA also gave the U.S. Nuclear Regulatory Commission (NRC) the responsibility for licensing and regulating uranium production and related activities, including decommissioning. Because there are many issues associated with decommissioning-environmental, political, and financial-this report will concentrate on the answers to three questions: (1) What is required? (2) How is the process implemented? (3) What are the costs? Regulatory control is exercised principally through the NRC licensing process. Before receiving a license to construct and operate an uranium producing facility, the applicant is required to present a decommissioning plan to the NRC. Once the plan is approved, the licensee must post a surety to guarantee that funds will be available to execute the plan and reclaim the site. This report by the Energy Information Administration (EIA) represents the most comprehensive study on this topic by analyzing data on 33 (out of 43) uranium production facilities located in Colorado, Nebraska, New Mexico, South Dakota, Texas, Utah, and Washington.

  3. Study of Natural Background Radiation around Gurvanbulag Uranium Deposit Area

    NASA Astrophysics Data System (ADS)

    Enkhbat, N.; Norov, N.; Bat-Erdene, B.; Khuukhenkhuu, G.; Otgooloi, B.

    2009-03-01

    In this work, we will show the study of natural background radiation level around the Gurvanbulag (GB) uranium deposit area in the eastern part of Mongolia. We collected environmental soil samples from 102 points around GB Uranium deposit. Collected samples were measured by HPGe gamma spectrometer at Nuclear Research Center, National University of Mongolia. The averaged activity concentrations of Ra-226, Th-232, K-40, and Cs-137 were 37.1, 29, 939, and 17.7 Bq/kg, respectively.

  4. Investigating uranium distribution in surface sediments and waters: a case study of contamination from the Juniper Uranium Mine, Stanislaus National Forest, CA.

    PubMed

    Kayzar, Theresa M; Villa, Adam C; Lobaugh, Megan L; Gaffney, Amy M; Williams, Ross W

    2014-10-01

    The uranium concentrations and isotopic compositions of waters, sediment leachates and sediments from Red Rock Creek in the Stanislaus National Forest of California were measured to investigate the transport of uranium from a point source (the Juniper Uranium Mine) to a natural surface stream environment. The ((234)U)/((238)U) composition of Red Rock Creek is altered downstream of the Juniper Mine. As a result of mine-derived contamination, water ((234)U)/((238)U) ratios are 67% lower than in water upstream of the mine (1.114-1.127 ± 0.009 in the contaminated waters versus 1.676 in the clean branch of the stream), and sediment samples have activity ratios in equilibrium in the clean creek and out of equilibrium in the contaminated creek (1.041-1.102 ± 0.007). Uranium concentrations in water, sediment and sediment leachates are highest downstream of the mine, but decrease rapidly after mixing with the clean branch of the stream. Uranium content and compositions of the contaminated creek headwaters relative to the mine tailings of the Juniper Mine suggest that uranium has been weathered from the mine and deposited in the creek. The distribution of uranium between sediment surfaces (leachable fraction) and bulk sediment suggests that adsorption is a key element of transfer along the creek. In clean creek samples, uranium is concentrated in the sediment residues, whereas in the contaminated creek, uranium is concentrated on the sediment surfaces (∼70-80% of uranium in leachable fraction). Contamination only exceeds the EPA maximum contaminant level (MCL) for drinking water in the sample with the closest proximity to the mine. Isotopic characterization of the uranium in this system coupled with concentration measurements suggest that the current state of contamination in Red Rock Creek is best described by mixing between the clean creek and contaminated upper branch of Red Rock Creek rather than mixing directly with mine sediment. PMID:24915114

  5. Investigating uranium distribution in surface sediments and waters: a case study of contamination from the Juniper Uranium Mine, Stanislaus National Forest, CA.

    PubMed

    Kayzar, Theresa M; Villa, Adam C; Lobaugh, Megan L; Gaffney, Amy M; Williams, Ross W

    2014-10-01

    The uranium concentrations and isotopic compositions of waters, sediment leachates and sediments from Red Rock Creek in the Stanislaus National Forest of California were measured to investigate the transport of uranium from a point source (the Juniper Uranium Mine) to a natural surface stream environment. The ((234)U)/((238)U) composition of Red Rock Creek is altered downstream of the Juniper Mine. As a result of mine-derived contamination, water ((234)U)/((238)U) ratios are 67% lower than in water upstream of the mine (1.114-1.127 ± 0.009 in the contaminated waters versus 1.676 in the clean branch of the stream), and sediment samples have activity ratios in equilibrium in the clean creek and out of equilibrium in the contaminated creek (1.041-1.102 ± 0.007). Uranium concentrations in water, sediment and sediment leachates are highest downstream of the mine, but decrease rapidly after mixing with the clean branch of the stream. Uranium content and compositions of the contaminated creek headwaters relative to the mine tailings of the Juniper Mine suggest that uranium has been weathered from the mine and deposited in the creek. The distribution of uranium between sediment surfaces (leachable fraction) and bulk sediment suggests that adsorption is a key element of transfer along the creek. In clean creek samples, uranium is concentrated in the sediment residues, whereas in the contaminated creek, uranium is concentrated on the sediment surfaces (∼70-80% of uranium in leachable fraction). Contamination only exceeds the EPA maximum contaminant level (MCL) for drinking water in the sample with the closest proximity to the mine. Isotopic characterization of the uranium in this system coupled with concentration measurements suggest that the current state of contamination in Red Rock Creek is best described by mixing between the clean creek and contaminated upper branch of Red Rock Creek rather than mixing directly with mine sediment.

  6. EXTRACTION OF URANIUM

    DOEpatents

    Kesler, R.D.; Rabb, D.D.

    1959-07-28

    An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

  7. Process for recovering uranium

    DOEpatents

    MacWood, G. E.; Wilder, C. D.; Altman, D.

    1959-03-24

    A process useful in recovering uranium from deposits on stainless steel liner surfaces of calutrons is presented. The deposit is removed from the stainless steel surface by washing with aqueous nitric acid. The solution obtained containing uranium, chromium, nickel, copper, and iron is treated with an excess of ammonium hydroxide to precipitnte the uranium, iron, and chromium and convert the nickel and copper to soluble ammonio complexions. The precipitated material is removed, dried and treated with carbon tetrachloride at an elevated temperature of about 500 to 600 deg C to form a vapor mixture of UCl/ sub 4/, UCl/sub 5/, FeCl/sub 3/, and CrCl/sub 4/. The UCl/sub 4/ is separated from this vapor mixture by selective fractional condensation at a temperature of about 500 to 400 deg C.

  8. PROCESS FOR RECOVERING URANIUM

    DOEpatents

    MacWood, G.E.; Wilder, C.D.; Altman, D.

    1959-03-24

    A process is described for recovering uranium from deposits on stainless steel liner surfaces of calutrons. The deposit is removed from the stainless steel surface by washing with aqueous nitric acid. The solution obtained containing uranium, chromium, nickels copper, and iron is treated with excess of ammonium hydroxide to precipitatc the uranium, irons and chromium and convert thc nickel and copper to soluble ammonia complexions. The precipitated material is removed, dried, and treated with carbon tetrachloride at an elevated temperature of about 500 to 600 deg C to form a vapor mixture of UCl/sub 4/, UCl/sub 5/, FeCl/ sub 3/, and CrCl/sub 4/. The UCl/sub 4/ is separated from this vapor mixture by selective fractional condensation at a temprrature of about 300 to400 deg C.

  9. Uranium immobilization and nuclear waste

    SciTech Connect

    Duffy, C.J.; Ogard, A.E.

    1982-02-01

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  10. PROCESS OF PREPARING URANIUM CARBIDE

    DOEpatents

    Miller, W.E.; Stethers, H.L.; Johnson, T.R.

    1964-03-24

    A process of preparing uranium monocarbide is de scribed. Uranium metal is dissolved in cadmium, zinc, cadmium-- zinc, or magnesium-- zinc alloy and a small quantity of alkali metal is added. Addition of stoichiometric amounts of carbon at 500 to 820 deg C then precipitates uranium monocarbide. (AEC)

  11. Uranium-series disequilibria as a means to study recent migration of uranium in a sandstone-hosted uranium deposit, NW China.

    PubMed

    Min, Maozhong; Peng, Xinjian; Wang, Jinping; Osmond, J K

    2005-07-01

    Uranium concentration and alpha specific activities of uranium decay series nuclides (234)U, (238)U, (230)Th, (232)Th and (226)Ra were measured for 16 oxidized host sandstone samples, 36 oxic-anoxic (mineralized) sandstone samples and three unaltered primary sandstone samples collected from the Shihongtan deposit. The results show that most of the ores and host sandstones have close to secular equilibrium alpha activity ratios for (234)U/(238)U, (230)Th/(238)U, (230)Th/(234)U and (226)Ra/(230)Th, indicating that intensive groundwater-rock/ore interaction and uranium migration have not taken place in the deposit during the last 1.0 Ma. However, some of the old uranium ore bodies have locally undergone leaching in the oxidizing environment during the past 300 ka to 1.0 Ma or to the present, and a number of new U ore bodies have grown in the oxic-anoxic transition (mineralized) subzone during the past 1.0 Ma. Locally, uranium leaching has taken place during the past 300 ka to 1.0 Ma, and perhaps is still going on now in some sandstones of the oxidizing subzone. However, uranium accumulation has locally occurred in some sandstones of the oxidizing environment during the past 1 ka to 1.0 Ma, which may be attributed to adsorption of U(VI) by clays contained in oxidized sandstones. A recent accumulation of uranium has locally taken place within the unaltered sandstones of the primary subzone close to the oxic-anoxic transition environment during the past 300 ka to 1.0 Ma. Results from the present study also indicate that uranium-series disequilibrium is an important tool to trace recent migration of uranium occurring in sandstone-hosted U deposits during the past 1.0 Ma and to distinguish the oxidation-reduction boundary.

  12. Agriculture in an area impacted by past uranium mining activities

    SciTech Connect

    Carvalho, F. P.; Oliveira, J. M.; Neves, O.; Vicente, E. M.; Abreu, M. M.

    2007-07-01

    The shallow aquifer near the old Cunha Baixa uranium mine (Viseu, Portugal) was contaminated by acid mine drainage. Concentration of radionuclides in water from irrigation wells and in the topsoil layer of the agriculture fields nearby display enhanced concentrations of uranium, radium and polonium. Two types of agriculture land in this area were selected, one with enhanced and another with low uranium concentrations, for controlled growth of lettuce and potatoes. Plants were grown in replicate portions of land (two plots) in each soil type and were periodically irrigated with water from wells. In each soil, one plot was irrigated with water containing low concentration of dissolved uranium and the other plot with water containing enhanced concentration of dissolved uranium. At the end of the growth season, plants were harvested and analysed, along with soil and irrigation water samples. Results show the accumulation of radionuclides in edible parts of plants, specially in the field plots with higher radionuclide concentrations in soil. Radionuclides in irrigation water contributed less to the radioactivity accumulated in plants than radionuclides from soils. (authors)

  13. Engineering paradigms and anthropogenic global change

    NASA Astrophysics Data System (ADS)

    Bohle, Martin

    2016-04-01

    This essay discusses 'paradigms' as means to conceive anthropogenic global change. Humankind alters earth-systems because of the number of people, the patterns of consumption of resources, and the alterations of environments. This process of anthropogenic global change is a composite consisting of societal (in the 'noosphere') and natural (in the 'bio-geosphere') features. Engineering intercedes these features; e.g. observing stratospheric ozone depletion has led to understanding it as a collateral artefact of a particular set of engineering choices. Beyond any specific use-case, engineering works have a common function; e.g. civil-engineering intersects economic activity and geosphere. People conceive their actions in the noosphere including giving purpose to their engineering. The 'noosphere' is the ensemble of social, cultural or political concepts ('shared subjective mental insights') of people. Among people's concepts are the paradigms how to shape environments, production systems and consumption patterns given their societal preferences. In that context, engineering is a means to implement a given development path. Four paradigms currently are distinguishable how to make anthropogenic global change happening. Among the 'engineering paradigms' for anthropogenic global change, 'adaptation' is a paradigm for a business-as-usual scenario and steady development paths of societies. Applying this paradigm implies to forecast the change to come, to appropriately design engineering works, and to maintain as far as possible the current production and consumption patterns. An alternative would be to adjust incrementally development paths of societies, namely to 'dovetail' anthropogenic and natural fluxes of matter and energy. To apply that paradigm research has to identify 'natural boundaries', how to modify production and consumption patterns, and how to tackle process in the noosphere to render alterations of common development paths acceptable. A further alternative

  14. PROCESS OF RECOVERING URANIUM

    DOEpatents

    Price, T.D.; Jeung, N.M.

    1958-06-17

    An improved precipitation method is described for the recovery of uranium from aqueous solutions. After removal of all but small amounts of Ni or Cu, and after complexing any iron present, the uranium is separated as the peroxide by adding H/sub 2/O/sub 2/. The improvement lies in the fact that the addition of H/sub 2/O/sub 2/ and consequent precipitation are carried out at a temperature below the freezing; point of the solution, so that minute crystals of solvent are present as seed crystals for the precipitation.

  15. PREPARATION OF URANIUM TRIOXIDE

    DOEpatents

    Buckingham, J.S.

    1959-09-01

    The production of uranium trioxide from aqueous solutions of uranyl nitrate is discussed. The uranium trioxide is produced by adding sulfur or a sulfur-containing compound, such as thiourea, sulfamic acid, sulfuric acid, and ammonium sulfate, to the uranyl solution in an amount of about 0.5% by weight of the uranyl nitrate hexahydrate, evaporating the solution to dryness, and calcining the dry residue. The trioxide obtained by this method furnished a dioxide with a considerably higher reactivity with hydrogen fluoride than a trioxide prepared without the sulfur additive.

  16. Corrosion-resistant uranium

    DOEpatents

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  17. Corrosion-resistant uranium

    DOEpatents

    Hovis, Jr., Victor M.; Pullen, William C.; Kollie, Thomas G.; Bell, Richard T.

    1983-01-01

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  18. PRODUCTION OF URANIUM TUBING

    DOEpatents

    Creutz, E.C.

    1958-04-15

    The manufacture of thin-walled uranium tubing by the hot-piercing techique is described. Uranium billets are preheated to a temperature above 780 d C. The heated billet is fed to a station where it is engaged on its external surface by three convex-surfaced rotating rollers which are set at an angle to the axis of the billet to produce a surface friction force in one direction to force the billet over a piercing mandrel. While being formed around the mandrel and before losing the desired shape, the tube thus formed is cooled by a water spray.

  19. Groundwater uranium origin and fate control in a river valley aquifer.

    PubMed

    Banning, Andre; Demmel, Thomas; Rüde, Thomas R; Wrobel, Michael

    2013-12-17

    Groundwater in a Quaternary gravel aquifer partly exhibits uranium (U) concentrations exceeding the new German drinking water limitation (22% of the samples >10 μg L(-1)). This study assesses relevant U reservoirs and hydrogeochemical processes responsible for U transfer between them. A large data set of solid materials (sediments and soils, 164 samples total) and groundwater (114 samples total) characteristics was created in terms of geo- and hydrochemistry, mineralogy, U microdistribution, and mobilization potential. Results show that U primarily derived from lignitic inclusions in Tertiary sediments is transported to and accumulated (complexation to organic substance and UO2 precipitation) in lowland moor peats of the river valley grown on the aquifer gravels. The alkaline character of the system predefines a hydrogeochemical framework fostering U mobility. Elevated concentrations (up to 96 μg L(-1) U) occur downstream of the moor areas and under Mn/NO3-reducing groundwater conditions. Oxic and stronger reduced settings are rather little affected. Supporting previous laboratory studies, this suggests enhanced U mobility in the presence of nitrate also in the field scale. While no anthropogenic U input was detected in the study area, agricultural usage of the moor areas triggers geogenic U release via nitrate fertilization, surface peat degradation, and erosion.

  20. Groundwater uranium and cancer incidence in South Carolina

    PubMed Central

    Wagner, Sara E.; Burch, James B.; Bottai, Matteo; Puett, Robin; Porter, Dwayne; Bolick-Aldrich, Susan; Temples, Tom; Wilkerson, Rebecca C.; Vena, John E.; Hébert, James R.

    2012-01-01

    Objective This ecologic study tested the hypothesis that census tracts with elevated groundwater uranium and more frequent groundwater use have increased cancer incidence. Methods Data sources included: incident total, leukemia, prostate, breast, colorectal, lung, kidney, and bladder cancers (1996–2005, SC Central Cancer Registry); demographic and groundwater use (1990 US Census); and groundwater uranium concentrations (n = 4,600, from existing federal and state databases). Kriging was used to predict average uranium concentrations within tracts. The relationship between uranium and standardized cancer incidence ratios was modeled among tracts with substantial groundwater use via linear or semiparametric regression, with and without stratification by the proportion of African Americans in each area. Results A total of 134,685 cancer cases were evaluated. Tracts with ≥50% groundwater use and uranium concentrations in the upper quartile had increased risks for colorectal, breast, kidney, prostate, and total cancer compared to referent tracts. Some of these relationships were more likely to be observed among tracts populated primarily by African Americans. Conclusion SC regions with elevated groundwater uranium and more groundwater use may have an increased incidence of certain cancers, although additional research is needed since the design precluded adjustment for race or other predictive factors at the individual level. PMID:21080052

  1. Biogenic and anthropogenic trace gases in the atmosphere

    NASA Technical Reports Server (NTRS)

    Brasseur, G. P.; Prinn, R. G.

    1992-01-01

    This paper illustrates the importance of biogenic and anthropogenic trace gases for the global environment and for the climate system. The paper briefly reviews the currently available estimates of sources and strengths of the biogenic and anthropogenic gases on the global scale. One of the major concerns for the global environment is the rapid increase in the concentration of long-lived trace gases such as CO2, CH4, N2O and the chlorofluorocarbons. The trend in the carbon dioxide concentration, as a result of fossil-fuel burning, is of the order of 0.4 percent per year, and this trend is related to the CO2 uptake by the ocean and by terrestrial ecosystems, which are likely to be modified if the planet warms up in the forthcoming decades. The concentrations of methane and nitrous oxide are increasing by 0.9 and 0.25 percent per year, respectively. In the case of the most widely used chlorofluorocarbons, trends as large as 10 percent per year or more are being measured.

  2. Solubility characterization of airborne uranium from a uranium recycling plant.

    PubMed

    Metzger, Robert; Cole, Leslie

    2004-07-01

    Solubility profiles of uranium dusts in a uranium recycling plant were determined by performing in vitro solubility tests on breathing zone air samples conducted in all process areas of the processing plant. The recycling plant produces high density shields, closed end tubes that are punched and formed from uranium sheet metal, and high-fired uranium oxide, which is used as a catalyst. The recycled uranium is cut and melted in a vacuum furnace, and part of the molten uranium is poured into molds for further processing. Air samples were taken in process areas under normal working conditions. The dissolution rate of the uranium in a simulant solution of extracellular airway lining fluid (Gamble's solution) was then determined over the next 28 d. Airborne uranium in the oxide section of the plant was found to be highly insoluble with 99% of the uranium having a dissolution half time in excess of 100 d. The solubility of the airborne uranium in other areas of the facility was only slightly more soluble with over 90% of the airborne uranium having dissolution half times in excess of 90 d.

  3. Bone as a possible target of chemical toxicity of natural uranium in drinking water.

    PubMed

    Kurttio, Päivi; Komulainen, Hannu; Leino, Aila; Salonen, Laina; Auvinen, Anssi; Saha, Heikki

    2005-01-01

    Uranium accumulates in bone, affects bone metabolism in laboratory animals, and when ingested in drinking water increases urinary excretion of calcium and phosphate, important components in the bone structure. However, little is known about bone effects of ingested natural uranium in humans. We studied 146 men and 142 women 26-83 years of age who for an average of 13 years had used drinking water originating from wells drilled in bedrock, in areas with naturally high uranium content. Biochemical indicators of bone formation were serum osteocalcin and amino-terminal propeptide of type I procollagen, and a marker for bone resorption was serum type I collagen carboxy-terminal telopeptide (CTx). The primary measure of uranium exposure was uranium concentration in drinking water, with additional information on uranium intake and uranium concentration in urine. The data were analyzed separately for men and women with robust regression (which suppresses contributions of potential influential observations) models with adjustment for age, smoking, and estrogen use. The median uranium concentration in drinking water was 27 microg/L (interquartile range, 6-116 microg/L). The median of daily uranium intake was 36 microg (7-207 microg) and of cumulative intake 0.12 g (0.02-0.66 g). There was some suggestion that elevation of CTx (p = 0.05) as well as osteocalcin (p = 0.19) could be associated with increased uranium exposure (uranium in water and intakes) in men, but no similar relationship was found in women. Accordingly, bone may be a target of chemical toxicity of uranium in humans, and more detailed evaluation of bone effects of natural uranium is warranted.

  4. Importance of Organic Matter-Uranium Biogeochemistry to Uranium Plume Persistence in the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Bargar, J.; Janot, N.; Jones, M. E.; Bone, S. E.; Lezama-Pacheco, J.; Fendorf, S. E.; Long, P. E.; Williams, K. H.; Bush, R. P.

    2014-12-01

    Recent evidence suggests that biologically driven redox reactions, fueled by sedimentary lenses enriched in detrital organic matter, play major roles in maintaining the persistent uranium groundwater plume in the subsurface at the U.S. Department of Enery's Rifle, CO field research site. Biogeochemical cycling of C, N, Fe, and S is highly active in these organic-rich naturally reduced zones (NRZs), and uranium is present as U(IV). The speciation of these elements profoundly influences the susceptibility of uranium to be reoxidized and remobiliized and contribute to plume persistence. However, uranim speciation in particular is poorly constrained in these sytems. To better evaluate the importance of NRZs to uranium mobility and plume persistence at the Rifle site, the DOE-BER-funded SLAC SFA team has characterized vertical concentration profiles and speciation of uranium, iron, sulfur, and NOM in well bores at high spatial resolution (4 inch intervals). Up to 95% of the sedimentary uranium pool was found to be concentrated in NRZs, where it occurs dominantly as non-crystalline forms of U(IV). Uranium accumulation and the presence of the short-lived sulfide mackinawite (FeS) at NRZ-aquifer interfaces indicate that NRZs actively exchange solutes with the surrounding aquifer. Moreover, sediment textures indicate that NRZs are likely to be abundant in riparian zones throughout the upper Colorado River basin (U.S.A.), which contains most of the contaminated DOE legacy uranium ore processing sites in the U.S. These results suggest that NRZ-uranium interactions may be important to plume persistence regionally and emphasize the importance of understanding molecular-scale processes.

  5. Redox dynamics in the Chesapeake Bay: The effect on sediment/water uranium exchange

    SciTech Connect

    Shaw, T.J.; Sholkovitz, E.R.; Klinkhammer, G. )

    1994-07-01

    The effect of seasonal variations in productivity and redox dynamics on the sediment/water exchange of uranium was investigated on a twelve cruise time series in the Chesapeake Bay. The deep waters of the bay undergo seasonal anoxia in response to high primary productivity and water column stratification from late spring to early fall. Dissolved oxygen was used to monitor sediment redox conditions. Dissolved [sup 238]U was measured in the water column and sediment porewaters to monitor water column/sediment exchange. Uranium incorporation in bay sediments results from two distinct processes: productivity-dependent scavenging from the water column and redox-dependent cycling of uranium between sediments and bottomwater. Uranium is removed from surface waters of the bay by scavenging with biodetritus during periods of high primary productivity. Bottomwater and sediment redox conditions determine whether this particle-bound uranium is buried or released to overlying water. Particulate uranium is released to bottomwaters and porewaters during the degradation of biodetritus and oxidation of authigenic uranium. Low oxygen in bottomwaters in the summer results in minimal exchange of uranium between the sediments and bottomwater, due to the stability of reduced U(IV). High bottomwater oxygen concentrations associated with bay turnover in the fall results in release of authigenic uranium by oxidation to the soluble (VI) form. Enrichment of uranium in fall bottomwater suggests that authigenic uranium is very labile when exposed to oxic environmental conditions. This process is enhanced by physical mixing when anoxic sediments are resuspended into the oxic bottomwaters.

  6. Isolating the anthropogenic component of Arctic warming

    SciTech Connect

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. We apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability from the observed temperature. We find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Furthermore, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.

  7. Isolating the anthropogenic component of Arctic warming

    DOE PAGESBeta

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. We apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability frommore » the observed temperature. We find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Furthermore, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.« less

  8. Treatability Test Plan for 300 Area Uranium Stabilization through Polyphosphate Injection

    SciTech Connect

    Vermeul, Vincent R.; Williams, Mark D.; Fritz, Brad G.; Mackley, Rob D.; Mendoza, Donaldo P.; Newcomer, Darrell R.; Rockhold, Mark L.; Williams, Bruce A.; Wellman, Dawn M.

    2007-06-01

    The U.S. Department of Energy has initiated a study into possible options for stabilizing uranium at the 300 Area using polyphosphate injection. As part of this effort, PNNL will perform bench- and field-scale treatability testing designed to evaluate the efficacy of using polyphosphate injections to reduced uranium concentrations in the groundwater to meet drinking water standards (30 ug/L) in situ. This technology works by forming phosphate minerals (autunite and apatite) in the aquifer that directly sequester the existing aqueous uranium in autunite minerals and precipitates apatite minerals for sorption and long term treatment of uranium migrating into the treatment zone, thus reducing current and future aqueous uranium concentrations. Polyphosphate injection was selected for testing based on technology screening as part of the 300-FF-5 Phase III Feasibility Study for treatment of uranium in the 300-Area.

  9. RECOVERY OF URANIUM FROM PITCHBLENDE

    DOEpatents

    Ruehle, A.E.

    1958-06-24

    The decontamination of uranium from molybdenum is described. When acid solutions containing uranyl nitrate are contacted with ether for the purpose of extracting the uranium values, complex molybdenum compounds are coextracted with the uranium and also again back-extracted from the ether with the uranium. This invention provides a process for extracting uranium in which coextraction of molybdenum is avoided. It has been found that polyhydric alcohols form complexes with molybdenum which are preferentially water-soluble are taken up by the ether extractant to only a very minor degree. The preferred embodiment of the process uses mannitol, sorbitol or a mixture of the two as the complexing agent.

  10. High loading uranium fuel plate

    DOEpatents

    Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

  11. Reaction of uranium oxides with chlorine and carbon or carbon monoxide to prepare uranium chlorides

    SciTech Connect

    Haas, P.A.; Lee, D.D.; Mailen, J.C.

    1991-11-01

    The preferred preparation concept of uranium metal for feed to an AVLIS uranium enrichment process requires preparation of uranium tetrachloride (UCI{sub 4}) by reacting uranium oxides (UO{sub 2}/UO{sub 3}) and chlorine (Cl{sub 2}) in a molten chloride salt medium. UO{sub 2} is a very stable metal oxide; thus, the chemical conversion requires both a chlorinating agent and a reducing agent that gives an oxide product which is much more stable than the corresponding chloride. Experimental studies in a quartz reactor of 4-cm ID have demonstrated the practically of some chemical flow sheets. Experimentation has illustrated a sequence of results concerning the chemical flow sheets. Tests with a graphite block at 850{degrees}C demonstrated rapid reactions of Cl{sub 2} and evolution of carbon dioxide (CO{sub 2}) as a product. Use of carbon monoxide (CO) as the reducing agent also gave rapid reactions of Cl{sub 2} and formation of CO{sub 2} at lower temperatures, but the reduction reactions were slower than the chlorinations. Carbon powder in the molten salt melt gave higher rates of reduction and better steady state utilization of Cl{sub 2}. Addition of UO{sub 2} feed while chlorination was in progress greatly improved the operation by avoiding the plugging effects from high UO{sub 2} concentrations and the poor Cl{sub 2} utilizations from low UO{sub 2} concentrations. An UO{sub 3} feed gave undesirable effects while a feed of UO{sub 2}-C spheres was excellent. The UO{sub 2}-C spheres also gave good rates of reaction as a fixed bed without any molten chloride salt. Results with a larger reactor and a bottom condenser for volatilized uranium show collection of condensed uranium chlorides as a loose powder and chlorine utilizations of 95--98% at high feed rates. 14 refs., 7 figs., 14 tabs.

  12. Uranium levels in Cypriot groundwater samples determined by ICP-MS and α-spectroscopy.

    PubMed

    Charalambous, Chrystalla; Aletrari, Maria; Piera, Panagiota; Nicolaidou-Kanari, Popi; Efstathiou, Maria; Pashalidis, Ioannis

    2013-02-01

    The uranium concentration and the isotopic ratio (238)U/(234)U have been determined in Cypriot groundwater samples by ICP-MS after ultrafiltration and acidification of the samples and α-spectroscopy after pre-concentration and separation of uranium by cation-exchange (Chelex 100 resin) and electro-deposition on stainless steel discs. The uranium concentration in the groundwater samples varies strongly between 0.1 and 40 μg l(-1). The highest uranium concentrations are found in groundwater samples associated with sedimentary rock formations and the obtained isotopic ratio (238)U/(234)U varies between 0.95 and 1.2 indicating basically the presence of natural uranium in the studied samples. The pH of the groundwater samples is neutral to weak alkaline (7 < pH < 8) and this is attributed to the carbonaceous content of the sedimentary rocks and the ophiolitic origin of the igneous rocks, which form the background geology in Cyprus. Generally, in groundwaters uranium concentration in solution increases with decreasing pH (7 < pH < 8) and this is attributed to the fact that at lower pH dissolution of soil minerals occurs, and uranium, which is adsorbed or forms solid solution with the geological matrix enters the aqueous phase. This is also corroborated by the strong correlation between the uranium concentration and the electrical conductivity (e.g. dissolved solids) measured in the groundwaters under investigation.

  13. Uranium levels in Cypriot groundwater samples determined by ICP-MS and α-spectroscopy.

    PubMed

    Charalambous, Chrystalla; Aletrari, Maria; Piera, Panagiota; Nicolaidou-Kanari, Popi; Efstathiou, Maria; Pashalidis, Ioannis

    2013-02-01

    The uranium concentration and the isotopic ratio (238)U/(234)U have been determined in Cypriot groundwater samples by ICP-MS after ultrafiltration and acidification of the samples and α-spectroscopy after pre-concentration and separation of uranium by cation-exchange (Chelex 100 resin) and electro-deposition on stainless steel discs. The uranium concentration in the groundwater samples varies strongly between 0.1 and 40 μg l(-1). The highest uranium concentrations are found in groundwater samples associated with sedimentary rock formations and the obtained isotopic ratio (238)U/(234)U varies between 0.95 and 1.2 indicating basically the presence of natural uranium in the studied samples. The pH of the groundwater samples is neutral to weak alkaline (7 < pH < 8) and this is attributed to the carbonaceous content of the sedimentary rocks and the ophiolitic origin of the igneous rocks, which form the background geology in Cyprus. Generally, in groundwaters uranium concentration in solution increases with decreasing pH (7 < pH < 8) and this is attributed to the fact that at lower pH dissolution of soil minerals occurs, and uranium, which is adsorbed or forms solid solution with the geological matrix enters the aqueous phase. This is also corroborated by the strong correlation between the uranium concentration and the electrical conductivity (e.g. dissolved solids) measured in the groundwaters under investigation. PMID:23195433

  14. Polyphosphate Remediation Technology for In-Situ Stabilization of Uranium

    SciTech Connect

    Wellman, Dawn M.; Pierce, Eric M.; Bacon, Diana H.; Fruchter, Jonathan S.; Vermeul, Vincent R.; Webb, Samuel M.

    2009-03-01

    A labortory testing program has been conducted to optimize polyphosphate remediation technology for implementation through a field-scale technology infiltration demonstration to stabilize soluble, uranium-bearing source phases in the vadose zone and capillary fringe. Source treatment in the deep vadose zone will accelerate the natural attenuation of uranium to more thermodynamically stable uranium-phosphate minerals, enhancing the performance of the proposed polyphosphate remediation within the 300 Area aquifer. The objective of this investigation was to develop polyphosphate remediation technology to treat uranium contamination contained within the deep vadose zone and capillary fringe. This paper presents the results of an investigation that evaluated the rate and extent of reaction between polyphosphate and the uranium mineral phases present within the 300 Area vadose zone and capillary fringe and autunite formation as a function of polyphosphate formulation and concentration. This information is critical for identifying the optimum implementation approach and controlling the flux of uranium from the vadose zone and capillary fringe to the underlying aquifer during remediation. Results from this investigation will be used to design a full-scale remediation of uranium at the 300 Area of the Hanford Site.

  15. Depleted uranium instead of lead in munitions: the lesser evil.

    PubMed

    Jargin, Sergei V

    2014-03-01

    Uranium has many similarities to lead in its exposure mechanisms, metabolism and target organs. However, lead is more toxic, which is reflected in the threshold limit values. The main potential hazard associated with depleted uranium is inhalation of the aerosols created when a projectile hits an armoured target. A person can be exposed to lead in similar ways. Accidental dangerous exposures can result from contact with both substances. Encountering uranium fragments is of minor significance because of the low penetration depth of alpha particles emitted by uranium: they are unable to penetrate even the superficial keratin layer of human skin. An additional cancer risk attributable to the uranium exposure might be significant only in case of prolonged contact of the contaminant with susceptible tissues. Lead intoxication can be observed in the wounded, in workers manufacturing munitions etc; moreover, lead has been documented to have a negative impact on the intellectual function of children at very low blood concentrations. It is concluded on the basis of the literature overview that replacement of lead by depleted uranium in munitions would be environmentally beneficial or largely insignificant because both lead and uranium are present in the environment. PMID:24594921

  16. Development of a Selective Calixarene Sensor for Uranium

    SciTech Connect

    Evans-Thompson, C.; Field, S. E.; Jones, A. H.; Kan, M. J.; Hall, C. W.; Nicholson, G. P.

    2002-02-26

    Traditionally, measurements of uranium in wastewater have been obtained by laboratory based instrumentation, such as inductively coupled plasma spectroscopy, ion-chromatography and radiochemical methods. However, such methods and equipment, whilst offering excellent sensitivity and reproducibility, are far too large and heavy to be portable. Therefore, there has been a lot of interest in developing a portable sensor to carry out uranium measurements. This work describes how a class of molecule called calixarenes have been used to develop a sensing methodology for measuring uranium concentration at low levels. This has been achieved by taking the established coordinating properties of the calixarene molecule for uranium and then adding functionalities to the molecule to make it adhere to metal surfaces. This way, a layer of the uranophilic molecule has been prepared on electrode surfaces, one molecule thick. These electrodes have been shown to be sensitive to uranium between 5 and 300 parts per billion. Using these modified electrodes, a portable device has been developed, which potentially allows for measurement of uranium in the field. This sensor therefore presents a very significant advantage in that it allows for rapid determination of low levels of uranium in wastewater, whilst offering portability.

  17. Selective removal of dissolved uranium in drinking water by nanofiltration.

    PubMed

    Favre-Réguillon, A; Lebuzit, G; Murat, D; Foos, J; Mansour, C; Draye, M

    2008-02-01

    A procedure for the selective removal of uranium traces dissolved in drinking water has been studied. Plate module membrane filtration equipment was operated to evaluate the performance and selectivity of three different nanofiltration flat-sheet membranes. Experiments were carried out using various commercial mineral waters with distinct physicochemical compositions. The membranes were first discriminating by their ability to reject uranium in the presence of the main cations found in mineral waters, using a 2 mg L(-1) (2000 ppb) concentration of uranium. The rejection of U(VI) was dependent on the uranyl speciation and the ionic strength. Second, removal of uranium traces (0.02 mg L(-1), 20 ppb) was performed using the nanofiltration membrane showing the highest selectivity for uranium toward alkaline and alkaline-earth ions. The results showed a high performance of the nanofiltration membrane, Osmonics DL, for selective uranium rejection at low pressure (1 bar), illustrating the advantage of nanofiltration for the selective removal of uranium from drinking water.

  18. STRIPPING OF URANIUM FROM ORGANIC EXTRACTANTS

    DOEpatents

    Crouse, D.J. Jr.

    1962-09-01

    A liquid-liquid extraction method is given for recovering uranium values from uranium-containing solutions. Uranium is removed from a uranium-containing organic solution by contacting said organic solution with an aqueous ammonium carbonate solution substantially saturated in uranium values. A uranium- containing precipitate is thereby formed which is separated from the organic and aqueous phases. Uranium values are recovered from this separated precipitate. (AE C)

  19. The Oceanic Sink for Anthropogenic CO2

    SciTech Connect

    Sabine, Chris; Feely, R. A.; Gruber, N.; Key, Robert; Lee, K.; Bullister, J.L.; Wanninkhof, R.; Wong, C. S.; Wallace, D.W.R.; Tilbrook, B.; Millero, F. J.; Peng, T.-H.; Kozyr, Alexander; Ono, Tsueno

    2004-01-01

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 19 petagrams of carbon. The oceanic sink accounts for ~48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  20. The oceanic sink for anthropogenic CO2.

    PubMed

    Sabine, Christopher L; Feely, Richard A; Gruber, Nicolas; Key, Robert M; Lee, Kitack; Bullister, John L; Wanninkhof, Rik; Wong, C S; Wallace, Douglas W R; Tilbrook, Bronte; Millero, Frank J; Peng, Tsung-Hung; Kozyr, Alexander; Ono, Tsueno; Rios, Aida F

    2004-07-16

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 +/- 19 petagrams of carbon. The oceanic sink accounts for approximately 48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 +/- 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  1. Anthropogenic Hg in the ocean: Trajectories of change and implications for exposure in the United States

    NASA Astrophysics Data System (ADS)

    Amos, H. M.; Corbitt, E. S.; Bullard, K. T.; Sunderland, E. M.

    2014-12-01

    Humans have been releasing mercury (Hg) to the environment for millenia through activities such as mining and fuel combustion. The result has been an enrichment of the ocean, atmosphere, and terrestrial ecosystems. Consumption of marine fish contaminated with methylmercury (MeHg) is the primary route of exposure in many populations globally. We present an updated analysis of sources of MeHg exposures in the United States that shows the majority (>70%) is from oceanic fish rather than coastal species. Using a fully coupled biogeochemical box model we also estimate Hg accumulation across major ocean basins and show anthropogenic enrichment is highest in the North Atlantic Ocean and lowest in the deep Pacific Ocean. Our results for contemporary ocean concentrations are consistent with recent data from the Pacific, Atlantic, Indian and Southern Oceans measured as part of the CLIVAR repeat hydrography program. Our estimates of natural (i.e., pre-anthropogenic) seawater Hg concentrations are lower than suggested by other studies, implying a greater anthropogenic perturbation in the ocean. Our work suggests total accumulation of anthropogenic Hg in the global oceans is greater than recently derived based on anthropogenic CO2. We compare modeled seawater concentrations since 1980 to observations over this period to evaluate evidence for changes in recent decades and then investigate potential impacts of changing global emissions. To do this, we use a range of historical and future anthropogenic Hg emission inventories. Our previous work using the box model indicates burial of Hg at ocean margins is the single largest global sink of anthropogenic Hg. We will discuss how the magnitude and permanence of this sink affects estimates of enrichment and time scales of recovery in all geochemical Hg reservoirs. Governing time scales of response in each ocean basin are diagnosed using eigenanalysis and discussed in the context of changes in human MeHg exposure resulting from

  2. Uranium, soluble salts

    Integrated Risk Information System (IRIS)

    Uranium , soluble salts ; no CASRN Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  3. The neurotoxicology of uranium.

    PubMed

    Dinocourt, Céline; Legrand, Marie; Dublineau, Isabelle; Lestaevel, Philippe

    2015-11-01

    The brain is a target of environmental toxic pollutants that impair cerebral functions. Uranium is present in the environment as a result of natural deposits and release by human applications. The first part of this review describes the passage of uranium into the brain, and its effects on neurological functions and cognitive abilities. Very few human studies have looked at its cognitive effects. Experimental studies show that after exposure, uranium can reach the brain and lead to neurobehavioral impairments, including increased locomotor activity, perturbation of the sleep-wake cycle, decreased memory, and increased anxiety. The mechanisms underlying these neurobehavioral disturbances are not clearly understood. It is evident that there must be more than one toxic mechanism and that it might include different targets in the brain. In the second part, we therefore review the principal mechanisms that have been investigated in experimental models: imbalance of the anti/pro-oxidant system and neurochemical and neurophysiological pathways. Uranium effects are clearly specific according to brain area, dose, and time. Nonetheless, this review demonstrates the paucity of data about its effects on developmental processes and the need for more attention to the consequences of exposure during development.

  4. URANIUM RECOVERY PROCESS

    DOEpatents

    Hyman, H.H.; Dreher, J.L.

    1959-07-01

    The recovery of uranium from the acidic aqueous metal waste solutions resulting from the bismuth phosphate carrier precipitation of plutonium from solutions of neutron irradiated uranium is described. The waste solutions consist of phosphoric acid, sulfuric acid, and uranium as a uranyl salt, together with salts of the fission products normally associated with neutron irradiated uranium. Generally, the process of the invention involves the partial neutralization of the waste solution with sodium hydroxide, followed by conversion of the solution to a pH 11 by mixing therewith sufficient sodium carbonate. The resultant carbonate-complexed waste is contacted with a titanated silica gel and the adsorbent separated from the aqueous medium. The aqueous solution is then mixed with sufficient acetic acid to bring the pH of the aqueous medium to between 4 and 5, whereby sodium uranyl acetate is precipitated. The precipitate is dissolved in nitric acid and the resulting solution preferably provided with salting out agents. Uranyl nitrate is recovered from the solution by extraction with an ether such as diethyl ether.

  5. Determination of uranium in natural waters

    USGS Publications Warehouse

    Barker, Franklin Butt; Johnson, J.O.; Edwards, K.W.; Robinson, B.P.

    1965-01-01

    A method is described for the determination of very low concentrations of uranium in water. The method is based on the fluorescence of uranium in a pad prepared by fusion of the dried solids from the water sample with a flux of 10 percent NaF 45.5 percent Na2CO3 , and 45.5 percent K2CO3 . This flux permits use of a low fusion temperature and yields pads which are easily removed from the platinum fusion dishes for fluorescence measurements. Uranium concentrations of less than 1 microgram per liter can be determined on a sample of 10 milliliters, or less. The sensitivity and accuracy of the method are dependent primarily on the purity of reagents used, the stability and linearity of the fluorimeter, and the concentration of quenching elements in the water residue. A purification step is recommended when the fluorescence is quenched by more than 30 percent. Equations are given for the calculation of standard deviations of analyses by this method. Graphs of error functions and representative data are also included.

  6. Semi-automatic version of the potentiometric titration method for characterization of uranium compounds.

    PubMed

    Cristiano, Bárbara F G; Delgado, José Ubiratan; da Silva, José Wanderley S; de Barros, Pedro D; de Araújo, Radier M S; Dias, Fábio C; Lopes, Ricardo T

    2012-09-01

    The potentiometric titration method was used for characterization of uranium compounds to be applied in intercomparison programs. The method is applied with traceability assured using a potassium dichromate primary standard. A semi-automatic version was developed to reduce the analysis time and the operator variation. The standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization and compatible with those obtained by manual techniques. PMID:22406220

  7. Occurrences of uranium-bearing minerals in the St. Kevin District, Lake County, Colorado

    USGS Publications Warehouse

    Pierson, C.T.; Singewald, Q.D.

    1953-01-01

    None of the uranium occurrences are of commercial importance. They are for the most part in non-glaciated terrane, which has been subjected to a very long period of weathering.  Thus, chemical leaching within the zone of weathering may have greatly reduced the uranium content of material near the surface, and occurrences of even small quantities of secondary uranium minerals might be related to stronger, primary concentrations at depth.

  8. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

    PubMed

    Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

    2010-03-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are <2 x 10(-14), and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  9. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

    PubMed

    Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

    2010-03-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are <2 x 10(-14), and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit. PMID:20136119

  10. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico

    SciTech Connect

    Goldstein, S.J.; Abdel-Fattah, A.I.; Murrell, M.T.; Dobson, P.F.; Norman, D.E.; Amato, R.S.; Nunn, A. J.

    2009-10-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ({approx}10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that {sup 230}Th/{sup 238}U activity ratios range from 0.005-0.48 and {sup 226}Ra/{sup 238}U activity ratios range from 0.006-113. {sup 239}Pu/{sup 238}U mass ratios for the saturated zone are <2 x 10{sup -14}, and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order {sup 238}U{approx}{sup 226}Ra > {sup 230}Th{approx}{sup 239}Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  11. Uptake and storage of anthropogenic CO2 in the pacific ocean estimated using two modeling approaches

    NASA Astrophysics Data System (ADS)

    Li, Yangchun; Xu, Yongfu

    2012-07-01

    A basin-wide ocean general circulation model (OGCM) of the Pacific Ocean is employed to estimate the uptake and storage of anthropogenic CO2 using two different simulation approaches. The simulation (named BIO) makes use of a carbon model with biological processes and full thermodynamic equations to calculate surface water partial pressure of CO2, whereas the other simulation (named PTB) makes use of a perturbation approach to calculate surface water partial pressure of anthropogenic CO2. The results from the two simulations agree well with the estimates based on observation data in most important aspects of the vertical distribution as well as the total inventory of anthropogenic carbon. The storage of anthropogenic carbon from BIO is closer to the observation-based estimate than that from PTB. The Revelle factor in 1994 obtained in BIO is generally larger than that obtained in PTB in the whole Pacific, except for the subtropical South Pacific. This, to large extent, leads to the difference in the surface anthropogenic CO2 concentration between the two runs. The relative difference in the annual uptake between the two runs is almost constant during the integration processes after 1850. This is probably not caused by dissolved inorganic carbon (DIC), but rather by a factor independent of time. In both runs, the rate of change in anthropogenic CO2 fluxes with time is consistent with the rate of change in the growth rate of atmospheric partial pressure of CO2.

  12. Fluid-bed fluoride volatility process recovers uranium from spent uranium alloy fuels

    NASA Technical Reports Server (NTRS)

    Barghusen, J. J.; Chilenskas, A. A.; Gunderson, G. E.; Holmes, J. T.; Jonke, A. A.; Kincinas, J. E.; Levitz, N. M.; Potts, G. L.; Ramaswami, D.; Stethers, H.; Turner, K. S.

    1967-01-01

    Fluid-bed fluoride volatility process recovers uranium from uranium fuels containing either zirconium or aluminum. The uranium is recovered as uranium hexafluoride. The process requires few operations in simple, compact equipment, and eliminates aqueous radioactive wastes.

  13. Final Technical Report - In-line Uranium Immunosensor

    SciTech Connect

    Blake, Diane A.

    2006-07-05

    In this project, personnel at Tulane University and Sapidyne Instruments Inc. developed an in-line uranium immunosensor that could be used to determine the efficacy of specific in situ biostimulation approaches. This sensor was designed to operate autonomously over relatively long periods of time (2-10 days) and was able to provide near real-time data about uranium immobilization in the absence of personnel at the site of the biostimulation experiments. An alpha prototype of the in-line immmunosensor was delivered from Sapidyne Instruments to Tulane University in December of 2002 and a beta prototype was delivered in November of 2003. The beta prototype of this instrument (now available commercially from Sapidyne Instruments) was programmed to autonomously dilute standard uranium to final concentrations of 2.5 to 100 nM (0.6 to 24 ppb) in buffer containing a fluorescently labeled anti-uranium antibody and the uranium chelator, 2,9-dicarboxyl-1,10-phenanthroline. The assay limit of detection for hexavalent uranium was 5.8 nM or 1.38 ppb. This limit of detection is well below the drinking water standard of 30 ppb recently promulgated by the EPA. The assay showed excellent precision; the coefficients of variation (CV’s) in the linear range of the assay were less than 5% and CV’s never rose above 14%. Analytical recovery in the immunosensors-based assay was assessed by adding variable known quantities of uranium to purified water samples. A quantitative recovery (93.75% - 108.17%) was obtained for sample with concentrations from 7.5 to 20 nM (2-4.75 ppb). In August of 2005 the sensor was transported to Oak Ridge National Laboratory, for testing of water samples at the Criddle test site (see Wu et al., Environ. Sci. Technol. 40:3978-3985 2006 for a description of this site). In this first on-site test, the in-line sensor was able to accurately detect changes in the concentrations of uranium in effluent samples from this site. Although the absolute values for the

  14. Conversion and Blending Facility Highly enriched uranium to low enriched uranium as uranium hexafluoride. Revision 1

    SciTech Connect

    1995-07-05

    This report describes the Conversion and Blending Facility (CBF) which will have two missions: (1) convert surplus HEU materials to pure HEU UF{sub 6} and a (2) blend the pure HEU UF{sub 6} with diluent UF{sub 6} to produce LWR grade LEU-UF{sub 6}. The primary emphasis of this blending be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The chemical and isotopic concentrations of the blended LEU product will be held within the specifications required for LWR fuel. The blended LEU product will be offered to the United States Enrichment Corporation (USEC) to be sold as feed material to the commercial nuclear industry.

  15. Diversity of Uranium Reduction Processes in Oak Ridge Source Zone Sediment

    SciTech Connect

    Jennifer L. Nyman; Terence L. Marsh; Matt Ginder-Vogel; Scott Fendorf; Craig Criddle

    2004-03-17

    The conclusions of this paper are: (1) Under sediment and groundwater conditions representative of the source zone during treatment, the amendment of ethanol stimulated microbial uranium reduction. This transformation was apparently mediated by bacterial activity, as uranium was not reduced in sterilized microcosms. (2) Various soluble uranium concentration patterns highlight the significance of small-scale sediment and/or inoculum heterogeneity. Field-scale experimental results will likely be a composite of variable reaction rates on this dimension. (3) A rebound in uranium concentration suggests biological reduction rates had decreased until they were less than uranium desorption rates from the solid phase. As ethanol, acetate, and sulfate were depleted in microcosms with rebounding uranium concentration, the rate of microbial uranium reduction may have been limited by a lack of electron donor or acceptor. (4) Uranium was reduced concurrently with sulfate, perhaps due to greater bioavailability of soluble sulfate over ferric iron or due to greater initial numbers of sulfate-reducing bacteria in the inoculum. (5) T-RFLP indicated a shift in community structure as uranium was reduced, although the HhaI and MspI profiles were each dominated by one or two fragment lengths.

  16. Experiments and Modeling of Uranium Adsorption in the Presence of Other Ions in Simulated Seawater

    DOE PAGESBeta

    Ladshaw, Austin; Das, Sadananda; Liao, Wei-Po; Yiacoumi, Sotira; Janke, Christopher James; Mayes, Richard T.; Dai, Sheng; Tsouris, Costas

    2015-11-19

    Seawater contains uranium at an average concentration of 3.3 ppb, as well as a variety of other ions at either overwhelmingly higher or similar concentrations, which complicate the recovery of uranium. This report describes an investigation of the effects of various factors such as uranium speciation and presence of salts including sodium, calcium, magnesium, and bicarbonate, as well as trace elements such as vanadium on uranium adsorption kinetics in laboratory experiments. Adsorption models are also developed to describe the experimental data of uranium extraction from seawater. Results show that the presence of calcium and magnesium significantly slows down the uraniummore » adsorption kinetics. Vanadium can replace uranium from amidoxime-based adsorbent in the presence of sodium in the solution. Results also show that bicarbonate in the solution strongly competes with amidoxime for binding uranium, and thus slows down the uranium adsorption kinetics. Developed on the basis of the experimental findings, the model is capable of describing the effects of pH, ionic strength, temperature, and concentration of various species. The results of this work are useful in the understanding of the important factors that control the adsorbent capacity and kinetics of uranium uptake by amidoxime-based adsorbents.« less

  17. Recovery and Detection of Uranium (VI) From Building Materials

    SciTech Connect

    Greene, Philip A.; Copper, Christine L.; Berv, David; Ramsey, Jeremy D.; Collins, Greg E.

    2004-03-29

    As a legacy of the United States' 50 year old nuclear weapons program, the Department of Energy is responsible for cleaning up and decommissioning contaminated sites that were used for the production of these weapons. The method presented here addresses the problem of detecting and quantifying uranium (VI) in concrete. Specifically, the uranium (VI) is removed from concrete surfaces using a low pH buffer rinse that dissolves the surface layer. The amount of uranium in the wash solution can be quite low, even with extraction efficiencies exceeding 50 %. Therefore, the uranium is complexed with an organic chelating agent (arsenazo III) and concentrated using C18 solid phase extraction. Because the absorbance maximum of arsenazo III shifts upon binding to uranium, the concentrated complex can be detected using ultraviolet-visible spectroscopy. Low part-per-billion levels of uranium (VI) in cement can be detected by this method. Results of work related to other building material s such as stainless steel and plexiglass will also be reported.

  18. Biosorption of uranium by melanin: kinetic, equilibrium and thermodynamic studies.

    PubMed

    Saini, Amardeep Singh; Melo, Jose Savio

    2013-12-01

    Limitation of conventional techniques for the removal of heavy metals present at low concentrations, has led to the need for developing alternate technologies like biosorption. In the present study we describe the use of melanin pigment synthesized through green technology, for sorption of uranium from aqueous system. Biosynthesized melanin showed good uptake over a broad pH range. Removal of uranium was rapid and equilibrium was reached within 2h of contact. It was observed that the kinetic data fits well into Lagergren's pseudo-second order equation. A maximum loading capacity of 588.24 mg g(-1) was calculated from Langmuir plot. Thermodynamic studies performed revealed that sorption process was favorable. Binding of uranium on the surface of melanin was confirmed by FT-IR and energy dispersive spectroscopy (EDS). Thus, biosynthesized melanin can be efficiently used as a sorbent for removal of uranium from aqueous solution. PMID:24099972

  19. MICROBIAL TRANSFORMATIONS OF URANIUM AND ENVIRONMENTAL RESTORATION THROUGH BIOREMEDIATION.

    SciTech Connect

    FRANCIS,A.J.

    2002-09-10

    Microorganisms present in the natural environment play a significant role in the mobilization and immobilization of uranium. Fundamental understanding of the mechanisms of microbiological transformations of various chemical forms of uranium present in wastes and contaminated soils and water has led to the development of novel bioremediation processes. One process uses anaerobic bacteria to stabilize the radionuclides and toxic metals from the waste, with a concurrent reduction in volume due to the dissolution and removal of nontoxic elements from the waste matrix. In an another process, uranium and other toxic metals are removed from contaminated soils and wastes by extracting with the chelating agent citric acid. Uranium is recovered from the citric acid extract after biodegradation/photodegradation in a concentrated form as UO{sub 3} {center_dot} 2H{sub 2}O for recycling or appropriate disposal.

  20. Acid lakes from natural and anthropogenic causes

    SciTech Connect

    Patrick, R.; Binetti, V.P.; Halterman, S.G.

    1981-01-30

    Lakes may be acid because of natural ecological conditions or because of anthropogenic activities. Apparently there has been a recent increase in acidity of many lakes in the northeastern United States. Factors that may be contributing to this increase include the use by utilities of precipitators, sulfur scrubbers, and tall stacks; the use of petroleum; and methods of combustion of fossil fuels.