Uranium mineralization in the Wilson Creek and Cranberry Gneisses and the Grandfather Mountain Formation, North Carolina and Tennessee. National Uranium Resource Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagener, H.D.; McHone, J.G.

1982-10-01

Detailed petrologic investigations were conducted at 74 anomalies that have surface radioactivities of 5 to 300 times background in the Grandfather Mountain region of North Carolina and Tennessee. One or more specimens of radioactive rock and one specimen of nonanomalous (barren) rock were taken for chemical analysis from each of the 74 sites. The specimens were analyzed fluorometrically for uranium (U/sub 3/O/sub 8/) and for 29 other elements by emission spectroscopy. Of the radioactive specimens, 23 contained less than 100 ppM U/sub 3/O/sub 8/ and were either depleted in uranium because of leaching or were rich in thorium; 25 containedmore » more than 500 ppM U/sub 3/O/sub 8/, with a maximum of 33,000 ppM. Specimens collected as barren contained up to 65 ppM U/sub 3/O/sub 8/. The more uraniferous rocks of the region tend to contain the larger concentrations of trace amounts of base metals.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.

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. Nearlymore » 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.« less

Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, T.L.

1979-11-01

During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km/sup 2/ area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including 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 to 84.60 parts per billion (ppb) with a meanmore » of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle.« less

Uranium hydrogeochemical and stream sediment reconnaissance of the Albuquerque NTMS Quadrangle, New Mexico, including concentrations of forty-three additional elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maassen, L.W.; Bolivar, S.L.

1979-06-01

The Los Alamos Scientific Laboratory conducted a hydrogeochemical and stream sediment reconnaissance for uranium. Totals of 408 water and 1538 sediment samples were collected from 1802 locations over a 20 100-km/sup 2/ area at an average density of one location per 11 km/sup 2/. Water samples were collected from springs, wells, and streams; sediments samples were collected predominantly from streams, but also from springs. All water samples were analyzed for uranium and 12 other elements. Sediment samples were analyzed for uranium and 42 additional elements. The uranium concentrations in water samples range from below the detection limit of 0.02 ppBmore » to 194.06 ppB. The mean uranium concentration for all water types containing < 40 ppB uranium is 1.98 ppB. Six samples contained uranium concentrations > 40.00 ppB. Well waters have the highest mean uranium concentration; spring waters have the lowest. Clusters of water samples that contain anomalous uranium concentrations are delineated in nine areas. Sediments collected from the quadrangle have uranium concentrations that range between 0.63 ppM and 28.52 ppM, with a mean for all sediments of 3.53 ppM. Eight areas containing clusters of sediments with anomalous uranium concentrations are delineated. One cluster contains sample locations within the Ambrosia Lake uranium district. Five clusters of sediment samples with anomalous uranium concentrations were collected from streams that drain the Jemez volcanic field. Another cluster defines an area just northeast of Albuquerque where streams drain Precambrian rocks, predominantly granites, of the Sandia Mountains. The last cluster, consisting of spring sediments from Mesa Portales, was collected near the contact of the Tertiary Ojo Alamo sandstone with underlying Cretaceous sediments. Sediments from these springs exhibit some of the highest uranium values reported and are associated with high uranium/thorium ratios.« less

Long-term accumulation of uranium in bones of Wistar rats as a function of intake dosages.

PubMed

Arruda-Neto, J D T; Guevara, M V Manso; Nogueira, G P; Saiki, M; Cestari, A C; Shtejer, K; Deppman, A; Pereira Filho, J W; Garcia, F; Geraldo, L P; Gouveia, A N; Guzmán, F; Mesa, J; Rodriguez, O; Semmler, R; Vanin, V R

2004-01-01

Groups of Wistar rats were fed with ration doped with uranyl nitrate at concentration A ranging from 0.5 to 100 ppm, starting after the weaning period and lasting until the postpuberty period when the animals were sacrificed. Uranium in the ashes of bones was determined by neutron activation analysis. It was found that the uranium concentration in the bones, as a function of A, exhibits a change in its slope at approximately 20 ppm-a probable consequence of the malfunctioning of kidneys. The uranium transfer coefficient was obtained and an analytical expression was fitted into the data, thus allowing extrapolation down to low doses. Internal and localized doses were calculated. Absorbed doses exceeded the critical dose, even for the lowest uranium dosage.

Process for magnetic beneficiating petroleum cracking catalyst

DOEpatents

Doctor, R.D.

1993-10-05

A process is described for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded. 1 figures.

Process for magnetic beneficiating petroleum cracking catalyst

DOEpatents

Doctor, Richard D.

1993-01-01

A process for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded.

Laser fluorometric analysis of plants for uranium exploration

USGS Publications Warehouse

Harms, T.F.; Ward, F.N.; Erdman, J.A.

1981-01-01

A preliminary test of biogeochemical exploration for locating uranium occurrences in the Marfa Basin, Texas, was conducted in 1978. Only 6 of 74 plant samples (mostly catclaw mimosa, Mimosa biuncifera) contained uranium in amounts above the detection limit (0.4 ppm in the ash) of the conventional fluorometric method. The samples were then analyzed using a Scintrex UA-3 uranium analyzer* * Use of trade names in this paper is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey. - an instrument designed for direct analysis of uranium in water, and which can be conveniently used in a mobile field laboratory. The detection limit for uranium in plant ash (0.05 ppm) by this method is almost an order of magnitude lower than with the fluorometric conventional method. Only 1 of the 74 samples contained uranium below the detection limit of the new method. Accuracy and precision were determined to be satisfactory. Samples of plants growing on mineralized soils and nonmineralized soils show a 15-fold difference in uranium content; whereas the soils themselves (analyzed by delayed neutron activation analysis) show only a 4-fold difference. The method involves acid digestion of ashed tissue, extraction of uranium into ethyl acetate, destruction of the ethyl acetate, dissolution of the residue in 0.005% nitric acid, and measurement. ?? 1981.

Mechanisms of uranium interactions with hydroxyapatite: Implications for groundwater remediation

USGS Publications Warehouse

Fuller, C.C.; Bargar, J.R.; Davis, J.A.; Piana, M.J.

2002-01-01

The speciation of U(VI) sorbed to synthetic hydroxyapatite was investigated using a combination of U LIII-edge XAS, synchrotron XRD, batch uptake measurements, and SEM-EDS. The mechanisms of U(VI) removal by apatite were determined in order to evaluate the feasibility of apatitebased in-situ permeable reactive barriers (PRBs). In batch U(VI) uptake experiments with synthetic hydroxyapatite (HA), near complete removal of dissolved uranium (>99.5%) to <0.05 ??M was observed over a range of total U(VI) concentrations up to equimolar of the total P in the suspension. XRD and XAS analyses of U(VI)-reacted HA at sorbed concentrations ???4700 ppm U(VI) suggested that uranium(VI) phosphate, hydroxide, and carbonate solids were not present at these concentrations. Fits to EXAFS spectra indicate the presence of Ca neighbors at 3.81 A??. U-Ca separation, suggesting that U(VI) adsorbs to the HA surfaces as an inner-sphere complex. Uranium(VI) phosphate solid phases were not detected in HA with 4700 ppm sorbed U(VI) by backscatter SEM or EDS, in agreement with the surface complexation process. In contrast, U(VI) speciation in samples that exceeded 7000 ppm sorbed U(VI) included a crystalline uranium(VI) phosphate solid phase, identified as chernikovite by XRD. At these higher concentrations, a secondary, uranium(VI) phosphate solid was detected by SEM-EDS, consistent with chernikovite precipitation. Autunite formation occurred at total U:P molar ratios ???0.2. Our findings provide a basis for evaluating U(VI) sorption mechanisms by commercially available natural apatites for use in development of PRBs for groundwater U(VI) remediation.

MTBE inhaled alone and in combination with gasoline vapor: uptake, distribution, metabolism, and excretion in rats.

PubMed

Benson, J M; Barr, E B; Krone, J R

2001-05-01

The purpose of these studies was to extend previous evaluation of methyl tert-butyl ether (MTBE)* tissue distribution, metabolism, and excretion in rats to include concentrations more relevant to human exposure (4 and 40 ppm) and to determine the effects of coinhalation of the volatile fraction of unleaded gasoline on the tissue distribution, metabolism, and excretion of MTBE. Groups of male F344 rats were exposed nose-only for 4 hours to 4, 40, or 400 ppm 14C-MTBE or to 20 or 200 ppm of the light fraction of unleaded gasoline (LFG) containing 4 or 40 ppm 14C-MTBE, respectively. To evaluate the effects of repeated inhalation of LFG on MTBE tissue distribution, metabolism, and excretion, rats were exposed for 4 hours on each of 7 consecutive days to 20 or 200 ppm LFG with MTBE (4 or 40 ppm) followed on the eighth day by a similar exposure to LFG containing 14C-MTBE. Subgroups of rats were evaluated for respiratory parameters, initial body burdens, rates and routes of excretion, and tissue distribution and elimination. The concentrations of MTBE and its chief metabolite, tert-butyl alcohol (TBA), were measured in blood and kidney immediately after exposure, and the major urinary metabolites-2-hydroxyisobutyric acid (IBA) and 2-methyl-1,2-propanediol (2MePD)-were measured in urine. Inhalation of MTBE alone or as a component of LFG had no concentration-dependent effect on respiratory minute volume. The initial body burdens of MTBE equivalents achieved after 4 hours of exposure to MTBE did not increase linearly with exposure concentration. MTBE equivalents rapidly distributed to all tissues examined, with the largest percentages distributed to liver. The observed initial body burden did not increase linearly between 4 and 400 ppm. At 400 ppm, elimination half-times of MTBE equivalents from liver increased and from lung, kidney, and testes decreased compared with the two smaller doses. Furthermore, at 400 ppm the elimination half-time for volatile organic compounds (VOCs) in breath was significantly shorter and the percentage of the initial body burden of MTBE equivalents eliminated as VOCs in breath increased significantly. These changes probably reflect a saturation of blood with MTBE at 400 ppm and strongly suggest that the uptake and fate of MTBE are notably different at exposure concentrations above and below 400 ppm. Single and repeated coexposure to 20 and 200 ppm LFG with MTBE had opposite effects on the total body burden of MTBE equivalents present at the end of exposures compared with those achieved after 4 and 40 ppm MTBE exposures: 20 ppm LFG increased and 200 ppm LFG significantly decreased the burdens of MTBE equivalents present. The effects of coexposure to LFG on blood levels of MTBE equivalents paralleled the effects on body burden. These differences in overall uptake of MTBE equivalents cannot be attributed to alterations of minute volume. The reason for the increase in overall uptake after 20-ppm LFG exposure is not clear. Decreased MTBE absorption (uptake) after single and repeated coexposure to 200 ppm LFG may be due to a decrease in solubility of MTBE in blood caused by inhalation of other hydrocarbons. Investigations on the blood/air partition coefficient of MTBE in the absence and presence of LFG would be needed to confirm this hypothesis. Single and repeated coexposure to either 20 or 200 ppm LFG significantly decreased the percentage of the initial body burden from MTBE equivalents in tissues, including liver, kidney, and testes, immediately and 72 hours after

Uranium in granitic magmas: Part 1. Experimental determination of uranium solubility and fluid-melt partition coefficients in the uranium oxide-haplogranite-H 2O-Na 2CO 3 system at 720-770°C, 2 kbar

NASA Astrophysics Data System (ADS)

Peiffert, Chantal; Cuney, Michel; Nguyen-Trung, Chinh

1994-06-01

The solubility of uranium was investigated in both carbonated aqueous fluid and granitic melt in equilibrium in the system haplogranite-uranium oxide-H 2O-Na 2CO 3 (0.5-1 molal) at 720-770°C, 2 kbar, andƒo 2 fixed by Ni-NiO, Fe 3O 4-Fe 2O 3, and Cu 2O-CuO buffers. As complete solid solution exists between UO 2.00 and UO 2.25 (i.e., 75 mol% UO 2 + 25 mol% UO 3), three distinct uranium oxides: UO (2.01 ± 0.01), UO (2.1.0 ± 0.02), and UO (2.25 ± 0.02) were, respectively, obtained at equilibrium, under the three ƒo 2 conditions cited above. Thus, the percentage of U (VI) in uranium oxide increased with increasing log ƒo 2. The thermal decomposition of Na 2CO 3 to CO 2 and Na 2O led to the decrease of the sodium carbonate concentration from 0.5-1 molal to ~10 -2 molal in all aqueous fluids and to the dissolution of Na in the silicate melts. Crystal-free silicate glasses with four agpaitic coefficients, α = ( (Na+K)/Al) = 1.1, 1.3, 1.5, and 1.7 were obtained. The uranium solubility in 10 -2 m aqueous carbonated fluid ((8.1 ± 0.1) ≤ quench pH ≤ (8.9 ± 0.1)) was in the range 1-17 ppm and increased linearly with increasing ƒo 2 according to the expression: log (U) (ppm) = 0.09 ·log ƒo 2 (bar) + 1.47 . This equation is valid for the temperature range 720-770°C and 2 kbar. U(IV) carbonate possibly were major species in aqueous solutions under reducing conditions (Ni-NiO buffer) whereas U(VI) carbonate complexes dominated under higher oxidation conditions (Fe 3O 4-Fe 2O 3, Cu 2O-CuO buffers). The uranium content in silicate glasses varied in a large range (10 2-2 × 10 5 ppm) and log (U) (ppm) increases linearly with both ƒo 2, and α in the range 1.1-1.5 according to the equation log (U) (ppm) = 0.04 log ƒo 2 (bar) + 3.80α -1.34 . This equation is valid for (1)ƒ o 2 ranging from Ni-NiO to Cu 2O-CuO, and (2) the temperature range 720-770°C at 2 kbar. The effect of ƒo 2 on the uranium solubility in silicate melt slightly decreased with increasing α from 1.1 to 1.5. For α in the range 1.5-1.7, the effect of both ƒo 2 and agpaicity index on the uranium solubility was considerably reduced. The temperature variation in the range 720-770°C had no significant effect on the uranium solubility in either aqueous fluid or silicate melt. The partition coefficient (D fluid/melt) of uranium was in the range 10 -4.0-10 -1.5 and depended on both ƒo 2 and α according to the equation log D fluid/melt = 0.05 log ƒo 2 (bar) - 3.78α + 2.84 . The validity conditions of this equation are similar to those of the preceding one. Results obtained in the present study could be used to predict the geochemical behaviour of uranium during magma fractionation and to further understanding of the formation of uranium ore deposits related to partial melting or fractional crystallization of felsic magmas. The genesis of the Kvanefjeld (Ilimaussaq, Greenland) uranium deposit is discussed.

Uranium hydrogeochemical and stream sediment reconnaissance of the Cortez NTMS Quadrangle, Colorado/Utah, including concentrations of forty-three additional elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, R.G.

1979-05-01

During the summers of 1976, 1977, and 1978, 598 water and 1657 sediment samples were collected from 1775 locations within the 19,600-km/sup 2/ area of the Cortez Quadrangle, Colorado and Utah. Water samples were collected from streams, springs, and wells; sediment samples were collected from stream channels (wet and dry) and from springs. Each water sample was analyzed for 13 elements, and each sediment sample was analyzed for 43 elements. Uranium concentrations in water samples range from below the detection limit of 0.02 to 241.47 ppB and have a median of 0.87 ppB and a mean of 3.80 ppB. Backgroundmore » uranium concentrations are 2 to 5 ppB in several nonmountainous regions but are much lower in mountainous areas, particularly in the northeastern portion of the quadrangle. Water samples containing high uranium concentrations (>20 ppB) generally are associated with high conductivities, high concentrations of other metallic elements, and geologic units, such as the Mancos shale, that are unfavorable for uranium mineralization. However, four ground-water samples exhibit high uranium concentrations without concomitant high conductivities or high concentrations of other metallic elements. Two of these samples were collected from sites in the Slick Rock U--V district, and two were collected in the Morrison formation in the southern portion of the quadrangle where large uranium deposits are not known. Water samples collected from the northwestern corner of the quadrangle uniformly exhibit background uranium values but generally contain high nickel concentrations. In this area, U--Cu (White Canyon-type) deposits are hosted primarily by the Shinarump member of the Chinle formation. Uranium concentrations in sediment samples range from 0.51 to 76.41 ppM and have a median of 2.76 ppM and a mean of 3.08 ppM. Background uranium and metallic element concentrations decrease to the southwest from the highest values in the northeastern portion of the quadrangle.« less

Uranium uptake history, open-system behaviour and uranium-series ages of fossil Tridacna gigas from Huon Peninsula, Papua New Guinea

NASA Astrophysics Data System (ADS)

Ayling, Bridget F.; Eggins, Stephen; McCulloch, Malcolm T.; Chappell, John; Grün, Rainer; Mortimer, Graham

2017-09-01

Molluscs incorporate negligible uranium into their skeleton while they are living, with any uranium uptake occurring post-mortem. As such, closed-system U-series dating of molluscs is unlikely to provide reliable age constraints for marine deposits. Even the application of open-system U-series modelling is challenging, because uranium uptake and loss histories can affect time-integrated uranium distributions and are difficult to constrain. We investigate the chemical and isotopic distribution of uranium in fossil Tridacna gigas (giant clams) from Marine Isotope Stage (MIS) 5e (128-116 ka) and MIS 11 (424-374 ka) reefs at Huon Peninsula in Papua New Guinea. The large size of the clams enables detailed chemical and isotopic mapping of uranium using LA-ICPMS and LA-MC-ICPMS techniques. Within each fossil Tridacna specimen, marked differences in uranium concentrations are observed across the three Tridacna growth zones (outer, inner, hinge), with the outer and hinge zones being relatively enriched. In MIS 5e and MIS 11 Tridacna, the outer and hinge zones contain approximately 1 ppm and 5 ppm uranium respectively. In addition to uptake of uranium, loss of uranium appears prevalent, especially in the MIS 11 specimens. The effect of uranium loss is to elevate measured [230Th/238U] values with little effect on [234U/238U] values. Closed-system age estimates are on average 50% too young for the MIS 5e Tridacna, and 25% too young for the MIS 11 Tridacna. A complex, multi-stage uptake and loss history is interpreted for the fossil Tridacna and we demonstrate that they cannot provide independent, reliable geochronological controls on the timing of past reef growth at Huon Peninsula.

Removal of uranium from soil samples for ICP-OES analysis of RCRA metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wero, M.; Lederer-Cano, A.; Billy, C.

1995-12-01

Soil samples containing high levels of uranium present unique analytical problems when analyzed for toxic metals (Ag, As, Ba, Cd, Cr, Cu, Ni, Pb, Se and Tl) because of the spectral interference of uranium in the ICP-OES emission spectrometer. Methods to remove uranium from the digestates of soil samples, known to be high in uranium, have been developed that reduce the initial uranium concentration (1-3%) to less than 500 ppm. UTEVA ion exchange columns, used as an ICP-OES analytical pre-treatment, reduces uranium to acceptable levels, permitting good analytical results of the RCRA metals by ICP-OES.

Evaluation of natural and anthropogenic radioactivity in environmental samples from Kuwait using high-resolution gamma-ray spectrometry

NASA Astrophysics Data System (ADS)

Bajoga, Abubakar D.

A study of natural radioactivity from ninety different soil samples across the state of Kuwait was carried out with a view to ascertain the level of natural and/or man-made radioactivity from that area. There has been some concern on the levels of NORM following the First Gulf War in which approximately 300 tons of depleted uranium shells were used and in particular, whether it has a significant impact in the surrounding environment. This study uses gamma-spectroscopy in a low background measuring system employing a high resolution Hyper-Pure Germanium detector. The calculated specific activity concentrations are determined for the radionuclides 226Ra, 214Pb, 214Bi and 228Ac, 212Pb, 208Tl following the decays of the primordial radionuclides 238U and 232Th, respectively. The analysis also includes evaluations for the 235U decay chain. In particular, the 186 keV doublet transition is used together with the activity concentration values established from the decays of 214Bi and 214Pb to establish the 226Ra and 235U specific activity concentrations, which can be used to estimate the 235U:238U isotopic ratios and compare to the accepted value for naturally occurring material of 1:138. Specific activity concentration values have also been determined for the 40K and the anthropogenic radionuclide 137Cs (from fallout) were detected within the same samples. Results of the activity concentration gives mean value of 16.99±0.21, 12.79±0.14, 333±37 and 2.18±0.11 Bq/kg for 238U, 232Th, 40K, and 137Cs, respectively. The associated radiological hazard indices from these samples were found to have mean values of 29.13±0.35 nG/hr, 60.20±0.68 Bq/kg, and 35.30±0.40 µSv/year for the dose rates, radium equivalent, and annual dose equivalent, respectively. Analysed results of elemental concentrations of Uranium, Thorium and Potassium were also determined, and were found to range from 0.96±0.02 ppm to 2.53±0.02 ppm, 2.26±0.04 ppm to 5.23±0.05 ppm and a mean value of 1.21±0.03 % for 40K for the northern region, respectively. Overall result indicates values within the world average range. The results obtained for the 235U:238U isotopic ratio gives a mean value of 0.0462, which is consistent with the presence of natural material from the measured location.

Petroleum source rock evaluation of the Alum and Dictyonema Shales (Upper Cambrian-Lower Ordovician) in the Baltic Basin and Podlasie Depression (eastern Poland)

NASA Astrophysics Data System (ADS)

Kosakowski, Paweł; Kotarba, Maciej J.; Piestrzyński, Adam; Shogenova, Alla; Więcław, Dariusz

2017-03-01

We present geochemical characteristics of the Lower Palaeozoic shales deposited in the Baltic Basin and Podlasie Depression. In the study area, this strata are represented by the Upper Cambrian-Lower Ordovician Alum Shale recognized in southern Scandinavia and Polish offshore and a equivalent the Lower Tremadocian Dictyonema Shale from the northern Estonia and the Podlasie Depression in Poland. Geochemical analyses reveal that the Alum Shale and Dictyonema Shale present high contents of organic carbon. These deposits have the best source quality among the Lower Palaeozoic strata, and they are the best source rocks in the Baltic region. The bituminous shales complex has TOC contents up to ca. 22 wt%. The analysed rocks contain low-sulphur, oil-prone Type-II kerogen deposited in anoxic or sub-oxic conditions. The maturity of the Alum and Dictyonema Shales changes gradually, from the east and north-east to the west and south-west, i.e. in the direction of the Tornquist-Teisseyre Zone. Samples, located in the seashore of Estonia and in the Podlasie region, are immature and in the initial phase of "oil window". The mature shales were found in the central offshore part of the Polish Baltic Basin, and the late mature and overmature are located in the western part of the Baltic Basin. The Alum and Dictyonema Shales are characterized by a high grade of radioactive elements, especially uranium. The enrichment has a syngenetic or early diagenetic origin. The measured content of uranium reached up to 750 ppm and thorium up to 37 ppm.

Removal of uranium from aqueous HF solutions

DOEpatents

Pulley, Howard; Seltzer, Steven F.

1980-01-01

This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

Variation of Nb-Ta, Zr-Hf, Th-U and K-Cs in two diabase-granophyre suites

USGS Publications Warehouse

Gottfried, D.; Greenland, L.P.; Campbell, E.Y.

1968-01-01

Concentrations of Nb, Ta, Zr, Hf, Th, U and Cs have been determined in samples of igneous rocks representing the diabase-granophyre suites from Dillsburg, Pennsylvania, and Great Lake, Tasmania. Niobium and tantalum have a three to fourfold increase with differentiation in each of the suites. The chilled margin of the Great Lake intrusion contains half the niobium and tantalum content (5.3 ppm and 0.4 ppm, respectively) of the chilled basalt from Dillsburg (10 ppm and 0.9 ppm, respectively). The twofold difference between the suites is correlated with differences in their titanium content. The average Nb Ta ratios for each suite are similar: 13.5 for the Great Lake suite, and 14.4 for the Dillsburg suite. The zirconium content of the two suites is essentially the same and increases from 50 to 60 ppm in the chilled margins to 240-300 ppm in the granophyres. Hafnium is low in the early formed rocks (0.5 -1.5 ppm and achieves a maximum in the granophyres (5-8 ppm). The Zr Hfratio decreases from 68 to 33 with progressive differentiation. In the Dillsburg suite thorium and uranium increase from 2.6 ppm and 0.6 ppm, respectively, in the chilled samples to 11.8 ppm and 3.1 ppm in the granophyres. The chilled margin of the Great Lake suite contains 3.2 ppm thorium and 9.8 ppm uranium; the granophyre contains 11.2 ppm thorium and 2.8 ppm uranium. The average Th U ratios of the Dillsburg and Great Lake suites are nearly the same-4.1 and 4.4, respectively. Within each suite the Th U ratio remains quite constant. Cesium and the K Cs ratio do not vary systematically in the Dillsburg suite possibly because of redistribution or loss of cesium by complex geologic processes. Except for the chilled margin of the Great Lake suite, the variation of Cs and the K Cs ratio are in accord with theoretical considerations. Cesium increases from about 0.6 ppm in the lower zone to 3.5 ppm in the granophyre; the K Cs ratio varies from 10 ?? 103 in the lower zone to 6 ?? 103 in the granophyre. A comparison of the abundance of some of these elements is made with those reported on oceanic tholeiites from the Atlantic and Pacific oceans. Trace elements with large ionic radii (Th, U, Cs) are present in significantly greater concentrations in the two continental tholeiitic series than in the oceanic tholeiites. However, this does not seem to be true for lithophilic elements of smaller ionic radii (Zr and Nb). These trace element distribution patterns, when considered with other minor element and isotopic studies, indicate that 1. (1) crustal contamination does not entirely account for differences between continental and oceanic tholeiites, and 2. (2) the oceanic tholeiites do not necessarily delimit the geochemical characteristics of the mantle. ?? 1968.

Improving gross count gamma-ray logging in uranium mining with the NGRS probe

NASA Astrophysics Data System (ADS)

Carasco, C.; Pérot, B.; Ma, J.-L.; Toubon, H.; Dubille-Auchère, A.

2018-01-01

AREVA Mines and the Nuclear Measurement Laboratory of CEA Cadarache are collaborating to improve the sensitivity and precision of uranium concentration measurement by means of gamma ray logging. The determination of uranium concentration in boreholes is performed with the Natural Gamma Ray Sonde (NGRS) based on a NaI(Tl) scintillation detector. The total gamma count rate is converted into uranium concentration using a calibration coefficient measured in concrete blocks with known uranium concentration in the AREVA Mines calibration facility located in Bessines, France. Until now, to take into account gamma attenuation in a variety of boreholes diameters, tubing materials, diameters and thicknesses, filling fluid densities and compositions, a semi-empirical formula was used to correct the calibration coefficient measured in Bessines facility. In this work, we propose to use Monte Carlo simulations to improve gamma attenuation corrections. To this purpose, the NGRS probe and the calibration measurements in the standard concrete blocks have been modeled with MCNP computer code. The calibration coefficient determined by simulation, 5.3 s-1.ppmU-1 ± 10%, is in good agreement with the one measured in Bessines, 5.2 s-1.ppmU-1. Based on the validated MCNP model, several parametric studies have been performed. For instance, the rock density and chemical composition proved to have a limited impact on the calibration coefficient. However, gamma self-absorption in uranium leads to a nonlinear relationship between count rate and uranium concentration beyond approximately 1% of uranium weight fraction, the underestimation of the uranium content reaching more than a factor 2.5 for a 50 % uranium weight fraction. Next steps will concern parametric studies with different tubing materials, diameters and thicknesses, as well as different borehole filling fluids representative of real measurement conditions.

Uranium and thorium in the Kupferschiefer formation, Lower Zechstein, Poland

NASA Astrophysics Data System (ADS)

Piestrzyński, A.

1990-05-01

The Kupferschiefer in Poland has an increased U content. The facies high in organic matter are significantly enriched in U. The maximum values of U are mostly in the lower part of the Kupferschiefer sequence. The mean (x) U content in the Kupferschiefer from the Lubin-Sieroszowice district is 61.5 ppm and from the rest of the Polish Zechstein basin is about 26 ppm. Thorium occurs only in small quantities (x) = 1.5 and 5 ppm respectively). The high variance of U and Th in the Kupferschiefer is due to multistage diagenetic processes. The main U carrier is thucholite. The investigated thucholite showed a Th-content below 0.36 ppm. Thucholite with uraninite exolutions showed small (up to 1.0 wt.%) admixtures of U and thucholite without microscopically visible exsolutions (up to 37.85 wt.% U). The phosphates showed significant amounts of U (up to 0.24 wt.). The U content in the Kupferschiefer is significantly lower than in black shales from other part of the world. Uranium in the Lubin district is not economic.

Uranium hydrogeochemical and stream sediment reconnaissance of the Trinidad NTMS Quadrangle, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, W.A.; LaDelfe, C.M.; Weaver, T.A.

1978-10-01

During the field seasons of 1976 and 1977, 1,060 natural water and 1,240 waterborne sediment samples were collected from 1,768 locations in the Trinidad, Colorado, NTMS quadrangle. The samples from this 19,600-km/sup 2/ area were analyzed at the Los Alamos Scientific Laboratory for total uranium. The uranium concentrations in waters ranged from less than the detection limit of 0.02 parts per billion (ppb) to 88.3 ppb, with a mean value of 4.05 ppb. The concentrations in sediments ranged from 1.3 parts per million (ppM) to 721.9 ppM, with a mean value of 5.55 ppM. Based on simple statistical analyses ofmore » these data, arbitrary anomaly thresholds were set at 20 ppb for water samples and 12 ppM for sediment samples. By this definition, fifty-eight water and 39 sediment samples were considered anomalous. At least five areas delineated by the data appear to warrant more detailed investigations. Twenty-six anomalous water samples outline a broad area corresponding to the axis of the Apishapa uplift, seven others form a cluster in Huerfano Park, and five others outline a small area in the northern part of the San Luis Valley. Twenty-three anomalous sediment samples outline an area corresponding generally to Precambrian metamorphic rocks in the Culebra Range, and seven anomalous sediment samples form a cluster near Crestone Peak in the Sangre de Cristo Mountains.« less

SOLVENT EXTRACTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM FROM AQUEOUS ACIDIC SOLUTIONS OF NEUTRON IRRADIATED URANIUM

DOEpatents

Bruce, F.R.

1962-07-24

A solvent extraction process was developed for separating actinide elements including plutonium and uranium from fission products. By this method the ion content of the acidic aqueous solution is adjusted so that it contains more equivalents of total metal ions than equivalents of nitrate ions. Under these conditions the extractability of fission products is greatly decreased. (AEC)

Growth of High Purity Oxygen-Free Silicon by Cold Crucible Techniques.

DTIC Science & Technology

1982-06-01

Liquid Metals (A Review). High Temp.-High Pressures 2(6), 583-586, 1970. 1971 Knights, C.F. and Perkins, R. Levitation Melting of Uranium Mono- Carbide . J...content - typically I PPM or less. c) The crystals grown exhibited a high level of carbon contamination (2-30 PPM ) which we believe, is caused by the...grown from melts confined in the cold crucible exhibit an unusually low oxygen content - typically 1 PPM or less. c.) The crystals grown exhibited a

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Keri; Judge, Elizabeth J.; Dirmyer, Matthew R.

Surrogate nuclear explosive debris was synthesized and characterized for major, minor, and trace elemental composition as well as uranium isotopics. The samples consisted of an urban glass matrix, equal masses soda lime and cement, doped with 500 ppm uranium with varying enrichments. The surface and cross section morphology were measured with SEM, and the major elemental composition was determined by XPS. LA-ICP-MS was used to measure the uranium isotopic abundance comparing different sampling techniques. Furthermore, the results provide an example of the utility of LA-ICP-MS for forensics applications.

Distribution of uranium in the Bisbee district, Cochise County, Arizona

USGS Publications Warehouse

Wallace, Stewart R.

1956-01-01

The Bisbee district has been an important source of copper for many years, and substantial amounts of lead and zinc ore and minor amounts of manganese ore have been mined during certain periods. The copper deposits occur both as low-grade disseminated ore in the Sacramento Hill stock and as massive sulfide (and secondary oxide and carbonate) replacement bodies in Paleozoic limestones that are intruded by the stock and related igneous bodies. The lead-zinc production has come almost entirely from limestone replacement bodies. The disseminated ore exhibits no anomalous radioactivity, and samples from the Lavender pit contain from 0.002 to less than 0.001 percent equivalent uranium. The limestone replacement ores are distinctly radioactive and stoping areas can be readily distinguished from from unmineralized ground on the basis of radioactivity alone. The equivalent uranium content of the copper replacement ores ranges from 0.002 to 0.014 percent and averages about 0.005 percent; the lead-zinc replacement ores average more than 0.007 percent equivalent uranium. Most of the uranium in the copper ores of the district is retained in the smelter slag of a residual concentrate; the slag contains about 0.009 percent equivalent uranium. Uranium carried off each day by acid mine drainage is roughly equal to 1 percent of that being added to the slag dump. Although the total amount of uranium in the district is large, no minable concentrations of ore-grade material are known; samples of relatively high-grade material represent only small fractions of tons at any one locality.

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

Femtosecond Laser Ablation Multicollector ICPMS Analysis of Uranium Isotopes in NIST Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffin, Andrew M.; Springer, Kellen WE; Ward, Jesse D.

We have utilized femtosecond laser ablation coupled to multi-collector inductively couple plasma mass spectrometry to measure the uranium isotopic content of NIST 61x (x=0,2,4,6) glasses. The uranium content of these glasses is a linear two-component mixing between isotopically natural uranium and the isotopically depleted spike used in preparing the glasses. Laser ablation results match extremely well, generally within a few ppm, with solution analysis following sample dissolution and chemical separation. In addition to isotopic data, sample utilization efficiency measurements indicate that over 1% of ablated uranium atoms reach a mass spectrometer detector, making this technique extremely efficient. Laser sampling alsomore » allows for spatial analysis and our data indicate that rare uranium concentration inhomogeneities exist in NIST 616 glass.« less

Uranium isotope composition of a laterite profile during extreme weathering of basalt in Guangdong, South China

NASA Astrophysics Data System (ADS)

Huang, J.; Zhou, Z.; Gong, Y.; Lundstrom, C.; Huang, F.

2015-12-01

Rock weathering and soil formation in the critical zone are important for material cycle from the solid Earth to superficial system. Laterite is a major type of soil in South China forming at hot-humid climate, which has strong effect on the global uranium cycle. Uranium is closely related to the environmental redox condition because U is stable at U(Ⅳ) in anoxic condition and U(Ⅵ) as soluble uranyl ion (UO22+) under oxic circumstance. In order to understand the behavior of U isotopes during crust weathering, here we report uranium isotopic compositions of soil and base rock samples from a laterite profile originated from extreme weathering of basalt in Guangdong, South China. The uranium isotopic data were measured on a Nu Plasma MC-ICP-MS at the University of Illinois at Urbana-Champaign using the double spike method. The δ238U of BCR-1 is -0.29±0.03‰ (relative to the international standard CRM-112A), corresponding to a 238U/235U ratio of 137.911±0.004. Our result of BCR-1 agrees with previous analyses (e.g., -0.28‰ in Weyer et al. 2008) [1]. U contents of the laterite profile decrease from 1.9 ppm to 0.9 ppm with depth, and peak at 160 - 170 cm (2.3 ppm), much higher than the U content of base rocks (~0.5 ppm). In contrary, U/Th of laterites is lower than that of base rock (0.27) except the peak at the depth of 160-170 cm (0.38), indicating significant U loss during weathering. Notably, U isotope compositions of soils show a small variation from -0.38 to -0.28‰, consistent with the base rock within analytical error (0.05‰ to 0.08‰, 2sd). Such small variation can be explained by a "rind effect" (Wang et al., 2015) [2], by which U(Ⅳ) can be completely oxidized to U(VI) layer by layer during basalt weathering by dissolved oxygen. Therefore, our study indicates that U loss during basalt weathering at the hot-humid climate does not change U isotope composition of superficial water system. [1] Weyer S. et al. (2008) Natural fractionation of 238U/235U. GCA 72,345-359 [2] Wang X. et al. (2015) Isotope fractionation during oxidation of tetravalent uranium by dissolved oxygen. GCA 150, 160-170

Uranium delivery and uptake in a montane wetland, north-central Colorado, USA

USGS Publications Warehouse

Schumann, R. Randall; Zielinski, Robert A.; Otton, James K.; Pantea, Michael P.; Orem, William H.

2017-01-01

Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U concentrations in four springs and one seep ranged from 20 to 83 ppb (μg/l). Maximum U concentrations are ∼300 ppm (mg/kg) in lakebed sediments and >3000 ppm in peat. Uranium in lakebed sediments is primarily stratabound in the more organic-rich layers, but samples of similar organic content display variable U concentrations. Post-depositional modifications include variable additions of U delivered by groundwater. Uranium distribution in peat is heterogeneous and primarily controlled by proximity to groundwater-fed springs and seeps that act as local point sources of U, and by proximity to groundwater directed along the peat/lakebeds contact. Uranium is initially sorbed on various organic components of peat as oxidized U(VI) present in groundwater. Selective extractions indicate that the majority of sorbed U remains as the oxidized species despite reducing conditions that should favor formation of U(IV). Possible explanations are kinetic hindrances related to strong complex formation between uranyl and humic substances, inhibition of anaerobic bacterial activity by low supply of dissolved iron and sulfate, and by cold temperatures.

Synthesis and characterization of surrogate nuclear explosion debris: urban glass matrix

DOE PAGES

Campbell, Keri; Judge, Elizabeth J.; Dirmyer, Matthew R.; ...

2017-07-26

Surrogate nuclear explosive debris was synthesized and characterized for major, minor, and trace elemental composition as well as uranium isotopics. The samples consisted of an urban glass matrix, equal masses soda lime and cement, doped with 500 ppm uranium with varying enrichments. The surface and cross section morphology were measured with SEM, and the major elemental composition was determined by XPS. LA-ICP-MS was used to measure the uranium isotopic abundance comparing different sampling techniques. Furthermore, the results provide an example of the utility of LA-ICP-MS for forensics applications.

CMB-8 material balance system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langner, D.; Canada, T.; Ensslin, N.

1980-08-01

We describe the automated nondestructive assay (NDA) system installed at the Los Alamos Scientific Laboratory (LASL) Group CMB-8 uranium recovery facility. A random driver (RD) is used to measure the /sup 235/U content of various solids while a uranium solution assay system (USAS) measures the /sup 235/U or total uranium content of solutions over a concentration range of a few ppM to 400 g/l. Both instruments are interfaced to and controlled by a single minicomputer. The measurement principles, mechanical specifications, system software description, and operational instructions are described.

The uptake, distribution, metabolism, and excretion of methyl tertiary-butyl ether inhaled alone and in combination with gasoline vapor.

PubMed

Benson, Janet M; Tibbetts, Brad M; Barr, Edward B

2003-06-13

The purpose of these studies was to evaluate the tissue uptake, distribution, metabolism, and excretion of methyl tertiary-butyl ether (MTBE) in rats and to determine the effects of coinhalation of the volatile fraction of unleaded gasoline on these parameters. Male F344 rats were exposed nose-only once for 4 h to 4, 40, or 400 ppm 14C-MTBE and to 20 and 200 ppm of the light fraction of unleaded gasoline (LFG) containing 4 and 40 ppm 14C-MTBE, respectively. To evaluate the effects of repeated inhalation of LFG on the fate of inhaled MTBE, rats were exposed for 7 consecutive days to 20 and 200 ppm LFG followed on d 8 by exposure to LFG containing 14C-MTBE. Three subgroups of rats were included for evaluation of respiratory parameters, rates and routes of excretion, and tissue distribution and elimination. MTBE and its chief metabolite, tertiary-butyl alcohol, were quantitated in blood and kidney (immediately after exposure), and the major urinary metabolites, 2-hydroxyisobutyric acid and 2-methyl-1,2- propanediol, were identified and quantified in urine. Inhalation of MTBE alone or as a component of LFG had no concentration-dependent effect on respiratory minute volume. The initial body burdens (IBBs) of MTBE equivalents achieved after 4 h of exposure to MTBE did not increase linearly with exposure concentration. MTBE equivalents rapidly distributed to all tissues examined, with the largest percentages distributed to liver. Between 40 and 400 ppm, there was a significant reduction in percentage of the IBB present in the major organs examined, both immediately and 72 h after exposure. At 400 ppm, the elimination rates of MTBE equivalents from tissues changed significantly. Furthermore, at 400 ppm there was a significant decrease in the elimination half-time of volatile organic compounds (VOCs) in breath and a significant increase in the percentage of the IBB of MTBE equivalents eliminated as VOCs in breath. LFG coexposure significantly decreased the percentage of the MTBE equivalent IBBs in tissues and increased rates of elimination of MTBE equivalents. The study results indicate that the uptake and fate of inhaled MTBE are altered upon increasing exposure levels from 4 to 400 ppm, suggesting that toxic effects observed previously upon repeated inhalation of concentrations of 400 ppm or greater may not necessarily be linearly extrapolated to effects that might occur at lower concentrations. Furthermore, coexposure to LFG, whether acute or repeated, decreases tissue burdens of MTBE equivalents and enhances the elimination rate of MTBE and its metabolites, thereby potentially reducing the toxic effects of the MTBE compared to when it is inhaled alone.

Uranium-Loaded Water Treatment Resins: 'Equivalent Feed' at NRC and Agreement State-Licensed Uranium Recovery Facilities - 12094

DOE Office of Scientific and Technical Information (OSTI.GOV)

Camper, Larry W.; Michalak, Paul; Cohen, Stephen

Community Water Systems (CWSs) are required to remove uranium from drinking water to meet EPA standards. Similarly, mining operations are required to remove uranium from their dewatering discharges to meet permitted surface water discharge limits. Ion exchange (IX) is the primary treatment strategy used by these operations, which loads uranium onto resin beads. Presently, uranium-loaded resin from CWSs and mining operations can be disposed as a waste product or processed by NRC- or Agreement State-licensed uranium recovery facilities if that licensed facility has applied for and received permission to process 'alternate feed'. The disposal of uranium-loaded resin is costly andmore » the cost to amend a uranium recovery license to accept alternate feed can be a strong disincentive to commercial uranium recovery facilities. In response to this issue, the NRC issued a Regulatory Issue Summary (RIS) to clarify the agency's policy that uranium-loaded resin from CWSs and mining operations can be processed by NRC- or Agreement State-licensed uranium recovery facilities without the need for an alternate feed license amendment when these resins are essentially the same, chemically and physically, to resins that licensed uranium recovery facilities currently use (i.e., equivalent feed). NRC staff is clarifying its current alternate feed policy to declare IX resins as equivalent feed. This clarification is necessary to alleviate a regulatory and financial burden on facilities that filter uranium using IX resin, such as CWSs and mine dewatering operations. Disposing of those resins in a licensed facility could be 40 to 50 percent of the total operations and maintenance (O and M) cost for a CWS. Allowing uranium recovery facilities to treat these resins without requiring a license amendment lowers O and M costs and captures a valuable natural resource. (authors)« less

Superfund Record of Decision Amendment (EPA Region 6): Texarkana Wood Preserving Co. , Texarkana, TX, March 13, 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This decision document presents an amendment to the selected remedial action for the Texarkana Wood Preserving Co. Superfund Site. This amendment fundamentally changes the Record of Decision (ROD) executed by the Regional Administrator on September 25, 1990. This amended remedy will seal and contain soils contaminated with greater than 3 ppm (parts per million) benzo(a)pyrene equivalents, 2450 ppm total poly aromatic hydrocarbons (PAH), 20 ppb (parts per billion) as 2,3,7,8 TCDD equivalents and 150 ppm pentachlorophenol beneath a soil cap.

Reconnaissance for uranium in black shale, Northern Rocky Mountains and Great Plains, 1953

USGS Publications Warehouse

Mapel, W.J.

1954-01-01

Reconnaissance examinations for uranium in 22 formations containing black shale were conducted in parts of Montana, North Dakota, Utah, Idaho, and Oregon during 1953. About 150 samples from 80 outcrop localities and 5 oil and gas wells were submitted for uranium determinations. Most of the black shale deposits examined contain less than 0.003 percent uranium; however, thin beds of black shale at the base of the Mississippian system contain 0.005 percent uranium at 2 outcrop localities in southwestern Montana and as much as 0.007 percent uranium in a well in northeastern Montana. An eight-foot bed of phosphatic black shale at the base of the Brazer limestone of Late Mississippian age in Rich County, Utah, contains as much as 0.009 percent uranium. Commercial gamma ray logs of oil and gas wells drilled in Montana and adjacent parts of the Dakotas indicate that locally the Heath shale of Late Mississippian age contains as much as 0.01 percent equivalent uranium, and black shales of Late Cretaceous age contain as much as 0.008 percent equivalent uranium.

Uranium Redox Transformations after U(VI) Coprecipitation with Magnetite Nanoparticles.

PubMed

Pidchenko, Ivan; Kvashnina, Kristina O; Yokosawa, Tadahiro; Finck, Nicolas; Bahl, Sebastian; Schild, Dieter; Polly, Robert; Bohnert, Elke; Rossberg, André; Göttlicher, Jörg; Dardenne, Kathy; Rothe, Jörg; Schäfer, Thorsten; Geckeis, Horst; Vitova, Tonya

2017-02-21

Uranium redox states and speciation in magnetite nanoparticles coprecipitated with U(VI) for uranium loadings varying from 1000 to 10 000 ppm are investigated by X-ray absorption spectroscopy (XAS). It is demonstrated that the U M 4 high energy resolution X-ray absorption near edge structure (HR-XANES) method is capable to clearly characterize U(IV), U(V), and U(VI) existing simultaneously in the same sample. The contributions of the three different uranium redox states are quantified with the iterative transformation factor analysis (ITFA) method. U L 3 XAS and transmission electron microscopy (TEM) reveal that initially sorbed U(VI) species recrystallize to nonstoichiometric UO 2+x nanoparticles within 147 days when stored under anoxic conditions. These U(IV) species oxidize again when exposed to air. U M 4 HR-XANES data demonstrate strong contribution of U(V) at day 10 and that U(V) remains stable over 142 days under ambient conditions as shown for magnetite nanoparticles containing 1000 ppm U. U L 3 XAS indicates that this U(V) species is protected from oxidation likely incorporated into octahedral magnetite sites. XAS results are supported by density functional theory (DFT) calculations. Further characterization of the samples include powder X-ray diffraction (pXRD), scanning electron microscopy (SEM) and Fe 2p X-ray photoelectron spectroscopy (XPS).

RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salas, H.T.; Nalini, H.A. Jr.; Mendes, J.C.

2004-10-03

One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples withmore » total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.« less

The distribution and mobility of uranium in glassy and zeolitized tuff, Keg Mountain area, Utah, U.S.A.

USGS Publications Warehouse

Zielinski, R.A.; Lindsey, D.A.; Rosholt, J.N.

1980-01-01

The distribution and mobility of uranium in a diagenetically altered, 8 Ma old tuff in the Keg Mountain area, Utah, are modelled in this study. The modelling represents an improvement over similar earlier studies in that it: (1) considers a large number of samples (76) collected with good geologic control and exhibiting a wide range of alteration; (2) includes radiometric data for Th, K and RaeU (radium equivalent uranium) as well as U; (3) considers mineralogic and trace-element data for the same samples; and (4) analyzes the mineral and chemical covariation by multivariate statistical methods. The variation of U in the tuff is controlled mainly by its primary abundance in glass and by the relative abundance of non-uraniferous detritus and uraniferous accessory minerals. Alteration of glass to zeolite, even though extensive, caused no large or systematic change in the bulk concentration of U in the tuff. Some redistribution of U during diagenesis is indicated by association of U with minor alteration products such as opal and hydrous Fe-Mn oxide minerals. Isotopic studies indicate that the zeolitized tuff has been open to migration of U decay products during the last 0.8 Ma. The tuff of Keg Mountain has not lost a statistically detectable fraction of its original U, even though it has a high (??? 9 ppm) trace U content and has been extensively altered to zeolite. Similar studies in a variety of geological environments are required in order to identify the particular combination of conditions most favorable for liberation and migration of U from tuffs. ?? 1980.

The water, deuterium, gas and uranium content of tektites

USGS Publications Warehouse

Friedman, I.

1958-01-01

The water content, deuterium concentration of the water, total gas and uranium contents were determined on tektite samples and other glass samples from Texas, Australia, Philippine Islands, Java, French Indo-China, Czechoslovakia, Libyan Desert, Billiton Island, Thailand, French West Africa, Peru, and New Mexico. The water content ranges from 0.24 per cent for the Peru tektite, to 0.0002 per cent for a moldavite. The majority of the tektites have less than 0.05 per cent water, and average 0.005 per cent H2O by weight. No other gases were detected, the lower detection limit being about 1 p.p.m. by weight. The deuterium content of the water in tektites is in the same range as that in terrestrial waters, and varies from 0.010 mole per cent to 0.0166 mole per cent deuterium. The uranium content is about from 1 to 3 p.p.m. The possible origin of tektites is discussed. The experimental data presented favour their being originally terrestrial, but produced by some catastrophic event. An extra-terrestrial source is not ruled out. ?? 1958.

Method for cleaning bomb-reduced uranium derbies

DOEpatents

Banker, John G.; Wigginton, Hubert L.; Beck, David E.; Holcombe, Cressie E.

1981-01-01

The concentration of carbon in uranium metal ingots induction cast from derbies prepared by the bomb-reduction of uranium tetrafluoride in the presence of magnesium is effectively reduced to less than 100 ppm by removing residual magnesium fluoride from the surface of the derbies prior to casting. This magnesium fluoride is removed from the derbies by immersing them in an alkali metal salt bath which reacts with and decomposes the magnesium fluoride. A water quenching operation followed by a warm nitric acid bath and a water rinse removes the residual salt and reaction products from the derbies.

Method for cleaning bomb-reduced uranium derbies

DOEpatents

Banker, J.G.; Wigginton, H.L.; Beck, D.E.; Holcombe, C.E.

The concentration of carbon in uranium metal ingots induction cast from derbies prepared by the bomb-reduction of uranium tetrafluoride in the presence of magnesium is effectively reduced to less than 100 ppM by removing residual magnesium fluoride from the surface of the derbies prior to casting. This magnesium fluoride is removed from the derbies by immersing them in an alkali metal salt bath which reacts with and decomposes the magnesium fluoride. A water quenching operation followed by a warm nitric acid bath and a water rinse removes the residual salt and reaction products from the derbies.

Reconnaissance for radioactive materials in northeastern United States during 1952

USGS Publications Warehouse

McKeown, Francis A.; Klemic, Harry

1953-01-01

Reconnaissance for radioactive materials was made in parts of Maine, New York, New Jersey, and Pennsylvania. The primary objective was to examine the iron ore deposits and associated rocks in the Adirondack Mountains of New York and the Highlands of New Jersey. In addition, several deposits known or reported to contain radioactive minerals were examined to delimit their extent. Most of the deposits examined are not significant as possible sources of radioactive elements and the data pertaining to them are summarized in table form. Deposits that do warrant more description than can be given in table form are: Benson Mines, St. Lawrence County, N. Y.; Rutgers mine, Clinton County, N. Y.; Mineville Mines, Essex County, N. Y.l Canfield phosphate mine, Morris County, N. J.; Mullgan quarry, Hunterdon County, N. J.; and the Chestnut Hill-Marble Mountain area, Pennsylvania and New Jersey. The Old Bed in the Mineville district is the only deposit that may be economically significant. Apatite from Old Bed ore contains as much as 4.9 percent total rare earth. 0.04 percent thorium, and 0.018 percent uranium. Magnetite ore at the Rutgers mine contains radioactive zircon and apatite. Radioactivity measurements of outcrops and dump material show that the ore contains from 0.005 to 0.010 percent equivalent uranium. One sample of lean magnetite ore contains 0.006 percent equivalent uranium. Garnet-rich zones in the Benson Mines magnetite deposit contain as much as 0.017 equivalent uranium. Most of the rock and ore, however, contains about 0.005 percent equivalent uranium. Available data indicate that the garnet-rich zones are enriched in radioactive allanite. A shear zone in the Kittatinny limestone of Cambrian age at the Mulligan quarry contains uraniferous material. Radioactivity anomalies elsewhere in the quarry and in adjacent fields indicate that there may be other uraniferous shear zones. Assays of samples and measurements of outcrop radioactivity indicate that the uranium content of these zones is low; samples contain from 0.008 to 0.068 percent equivalent uranium. The anomalies, however, may indicate greater concentrations of uranium below surficial leached zones. The Chestnut Hill-Marble Mountain area contains radioactivity anomalies for about 2 miles along the strike of the contact of pre-Cambrian Pickering gneiss and Franklin limestone formations. In places this contact is injected with pegmatite, which probably was the source of the radioelements. The most favorable area for further study is at Marble Mountain, where a nearly continuous anomaly extends for about 1500 feet. Samples from part of this area contain as much as 0.044 percent equivalent uranium and 0.005 percent uranium. Radioactive hematite and florencite, in which thorium may have substituted for cerium, are the only radioactive minerals observed in the Marble Mountain area.

Uranium hydrogeochemical and stream sediment reconnaissance data from the area of the Shishmaref, Kotzebue, Selawik and Shungnak Quadrangles, northern Seward Peninsula and vicinity, Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, R.G.; Hill, D.E.; Sharp, R.R. Jr.

1978-05-01

During the summer of 1976, 1336 water and 1251 sediment samples were collected for Los Alamos Scientific Laboratory (LASL) from 1356 streams and small lakes or ponds within Shishmaref, Kotzebue, Selawik, and western portion of Shungnak NTMS quadrangles in western Alaska. Both a water and sediment sample were generally obtained from each location at a nominal location density of 1/23 km/sup 2/. Total uranium was measured in waters by fluorometry and in sediments and a few waters by delayed neutron counting at LASL. Uranium concentrations in waters have a mean of 0.31 ppB and a maximum of 9.23 ppB, andmore » sediments exhibit a mean of 3.44 ppM and a maximum of 37.7 ppM. A large number of high-uranium concentrations occur in both water and sediment samples collected in the Selawik Hills. At least two locations within the Selawik Hills appear favorable for further investigation of possible uranium mineralization. A cluster of high-uranium sediments, seen in the Waring Mountains, are probably derived from a lower Cretaceous conglomerate unit which is assocated with known airborne radiometric anomalies. Apparently less favorable areas for further investigation of possible uranium mineralization are also located in the Waring Mountains and Kiana Hills. Additional samples were collected within the Shungnak quadrange to increase the sampling density used elsewhere in the area to about one location per 11 km/sup 2/ (double-density). Contoured plots of uranium concentrations for both waters and sediments were prepared for all double-density sample locations, and then for the even-numbered and odd-numbered locations separately. These plots indicate that the HSSR sampling density of 1/23 km/sup 2/ used in lowland areas of Alaska provide essentially the same definition of relative areal uranium distributions in waters and sediments as seen when the density is doubled. These plots indicate that regional distribution patterns for uranium are well defined without selective sampling of geologic units.« less

Occupational safety considerations with hydrazine fuels

NASA Technical Reports Server (NTRS)

Clewell, H. J.; Haddad, T. S.; George, M. E.; Mcdougal, J. N.; Andersen, M. E.

1992-01-01

A simple pharmacokinetic model and a specially designed dermal vapor exposure chamber which provides respiratory protection were used to determine the rate of penetration of hydrazine and 1,1-dimethylhydrazine (UDMH) vapor through the skin of rats. Parameters for the pharmacokinetic model were determined from intravenous and inhalation exposure data. The model was then used to estimate the skin permeation coefficient for hydrazine or UDMH vapor from the dermal-vapor exposure data. This analysis indicates that UDMH vapor has a relatively high permeability through skin (0.7 cm/hr), a value somewhat higher than was obtained for hydrazine by the same procedure (0.09 cm/hr). Based on these skin permeability results, a skin-only vapor exposure limit giving protection equivalent to the inhalation Threshold Limit Value (TLV) could be calculated. The current TLV's for UDMH and hydrazine are 0.5 and 0.1 ppm, respectively. The corresponding skin-only TLV equivalents, for personnel wearing respiratory protection, are 32 ppm for UDMH and 48 ppm for hydrazine. Should the proposed lowering to the TLV's for these compounds to 0.01 ppm be adopted, the equivalent skin-only TLV's would become 0.64 ppm for UDMH and 4.8 for hydrazine.

Reconnaissance for radioactive deposits in eastern Alaska, 1952

USGS Publications Warehouse

Nelson, Arthur Edward; West, Walter S.; Matzko, John J.

1954-01-01

Reconnaissance for radioactive deposits was conducted in selected areas of eastern Alaska during 1952. Examination of copper, silver, and molybdenum occurrences and of a reported nickel prospect in the Slana-Nabesna and Chisana districts in the eastern Alaska Range revealed a maximum radioactivity of about 0.003 percent equivalent uranium. No appreciable radioactivity anomolies were indicated by aerial and foot traverses in the area. Reconnaissance for possible lode concentrations of uranium minerals in the vicinity of reported fluoride occurrences in the Hope Creek and Miller House-Circle Hot Springs areas of the Circle quadrangle and in the Fortymile district found a maximum of 0.055 percent equivalent uranium in a float fragment of ferruginous breccia in the Hope Creek area; analysis of samples obtained in the vicinity of the other fluoride occurrences showed a maximum of only 0.005 percent equivalent uranium. No uraniferous loads were discovered in the Koyukuk-Chandalar region, nor was the source of the monazite, previously reported in the placer concentrates from the Chandalar mining district, located. The source of the uranotheorianite in the placers at Gold Bench on the South Fork of the Koyukuk River was not found during a brief reconaissance, but a placer concentrate was obtained that contains 0.18 percent equivalent uranium. This concentrate is about ten times more radioactive than concentrates previously available from the area.

The passivation of uranium metal surfaces by nitrogen bombardment — the formation of uranium nitride

NASA Astrophysics Data System (ADS)

Allen, Geoffrey C.; Holmes, Nigel R.

1988-05-01

As part of a detailed investigation of the behaviour of metallic uranium in various atmospheres, we have examined the reaction between nitrogen gas and uranium metal. At room temperature there was no evidence of reaction between nitrogen gas and a clean metal surface; the only changes observed could be attributed to reaction between the metal and traces of oxygen (less than 0.1 ppm) in the nitrogen gas. Reaction between the metal and nitrogen was induced, however, by accelerating nitrogen towards the surface using a fast atom gun. The resulting nitrided surface was characterized by X-ray photoelectron spectroscopy, and its oxidation behaviour was monitored over an extended period in UHV and in air.

Diatremes of the Hopi Buttes, Arizona; chemical and statistical analyses

USGS Publications Warehouse

Wenrich, K.J.; Mascarenas, J.F.

1982-01-01

Lacustrine sediments deposited in maar lakes of the Hopi Buttes diatremes are hosts for uranium mineralization of as much as 1500 ppm. The monchiquites and limburgite turfs erupted from the diatremes are distinguished from normal alkalic basalts of the Colorado Plateau by their extreme silica undersaturation and high water, TiO2, and P2O5 contents. Many trace elements are also unusually abundant, including Ag, As, Ba, Be, Ce, Dy, Eu, F, Gd, Hf, La, Nd, Pb, Rb, Se, Sm, Sn, Sr, Ta, Tb, Th, U, V, Zn, and Zr. The lacustrine sediments, which consist predominantly of travertine and clastic rocks, are the hosts for syngenetic and epigenetic uranium mineralization of as much as 1500 ppm uranium. Fission track maps show the uranium to be disseminated within the travertine and clastic rocks, and although microprobe analyses have not, as yet, revealed discrete uranium-bearing phases, the clastic rocks show a correlation of high Fe, Ti, and P with areas of high U. Correlation coefficients show that for the travertines, clastics, and limburgite ruffs, Mo, As, Sr, Co, and V appear to have the most consistent and strongest correlations with uranium. Many elements, including many of the rare-earth elements, that are high in these three rocks are also high in the monchiquites, as compared to the average crustal abundance for the respective rock type. This similar suite of anomalous elements, which includes such immobile elements as the rare earths, suggests that Fluids which deposited the travertines were related to the monchiquitic magma. The similar age of about 5 m.y. for both the lake beds and the monchiquites also appears to support this source for the mineralizing fluids.

LuminoTox as a tool to optimize ozone doses for the removal of contaminants and their associated toxicity.

PubMed

Marshall, Meghan; Yargeau, Viviane

2018-03-01

New treatment technologies and quality monitoring tools are needed for Contaminants of Emerging Concern (CECs) in wastewater. The purpose of this work was to assess the LuminoTox as a monitoring tool for CEC-associated toxicity in municipal wastewater during ozone treatment, and to evaluate the impact of different ozone feed concentrations at equivalent ozone doses for removing toxicity. The LuminoTox was sensitive at monitoring changes in toxicity of atrazine (ATZ) in synthetic wastewater (SWW) and in a 14 CECs mix in secondary effluent (SE) during ozone treatment. In both experiments, a decrease in toxicity was observed with increasing transferred ozone dose, which corresponded to a decrease in CEC concentration. For ATZ in SWW, a 5 ppm ozone feed showed better toxicity removal, up to 25% and 35% inhibition for LuminoTox algae biosensors SAPS I and SAPS II, respectively, for statistically equivalent ozone dose pairs of 43 mg (5 ppm ozone feed) and 36 mg (15 ppm ozone feed). The opposite was true for the 14 CECs in SE; the 15 ppm ozone feed showed better toxicity removal, up to a reduction of 37% and 40% for SAPS I and SAPS II inhibition, respectively, for statistically equivalent ozone dose pairs of 42 mg (5 ppm ozone feed) and 42 mg (15 ppm ozone feed). Different feed applications had an impact on the efficiency of toxicity removal for equivalent ozone doses; this efficiency appears to depend on the type of contaminants and/or wastewater matrix. Copyright © 2017 Elsevier Ltd. All rights reserved.

78 FR 75262 - Flonicamid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-11

... publicly by EPA without prior notice. Submit the non-CBI copy of your objection or hearing request...- trifluoromethylnicotinamide), and TFNG (N-(4- trifluoromethylnicotinoyl)glycine), calculated as the stoichiometric equivalent..., tops at 7.0 ppm; spearmint, tops at 7.0 ppm; vegetable, fruiting, group 8-10 at 0.40 ppm; vegetable...

Modelling of the dissolution and reprecipitation of uranium under oxidising conditions in the zone of shallow groundwater circulation.

PubMed

Dutova, Ekaterina M; Nikitenkov, Aleksei N; Pokrovskiy, Vitaly D; Banks, David; Frengstad, Bjørn S; Parnachev, Valerii P

2017-11-01

Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO 2 pressure (P CO2 , open system) of 10 -2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L -1 . Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L -1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO 3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U 3 O 7 and U 4 O 9 ). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L -1 , but with typical concentrations of up to 10 μg L -1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and P CO2 (low P CO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals). Copyright © 2017 Elsevier Ltd. All rights reserved.

STUDY OF URANIUM-ALUMINUM-IRON TERNARY CONSTITUTION DIAGRAM. Progress Report for the Period Ending March 31, 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, R.B.

The determination of the U--Al-- Fe constitution diagram up to about 1000 ppm each of aluminum and iron is now being implemented by a determination of the U--Al and U-- Fe binary systems. The techniques to be used for this study include optical, electron and x-ray metallography, microprobe analysis, electrical resistance, and hothardness measurements. It is expected that a combination of techniques will give evidence of the amount of solid solubility of aluminum and iron in alpha uranium from 300 to 660 deg C, and in beta uranium at selected higher temperatures. (N.W.R.)

Uranium metallogenesis of the peraluminous leucogranite from the Pontivy-Rostrenen magmatic complex (French Armorican Variscan belt): the result of long-term oxidized hydrothermal alteration during strike-slip deformation

NASA Astrophysics Data System (ADS)

Ballouard, C.; Poujol, M.; Mercadier, J.; Deloule, E.; Boulvais, P.; Baele, J. M.; Cuney, M.; Cathelineau, M.

2018-06-01

In the French Armorican Variscan belt, most of the economically significant hydrothermal U deposits are spatially associated with peraluminous leucogranites emplaced along the south Armorican shear zone (SASZ), a dextral lithospheric scale wrench fault that recorded ductile deformation from ca. 315 to 300 Ma. In the Pontivy-Rostrenen complex, a composite intrusion, the U mineralization is spatially associated with brittle structures related to deformation along the SASZ. In contrast to monzogranite and quartz monzodiorite (3 < U < 9 ppm; Th/U > 3), the leucogranite samples are characterized by highly variable U contents ( 3 to 27 ppm) and Th/U ratios ( 0.1 to 5) suggesting that the crystallization of magmatic uranium oxide in the more evolved facies was followed by uranium oxide leaching during hydrothermal alteration and/or surface weathering. U-Pb dating of uranium oxides from the deposits reveals that they mostly formed between ca. 300 and 270 Ma. In monzogranite and quartz monzodiorite, apatite grains display magmatic textures and provide U-Pb ages of ca. 315 Ma reflecting the time of emplacement of the intrusions. In contrast, apatite grains from the leucogranite display textural, geochemical, and geochronological evidences for interaction with U-rich oxidized hydrothermal fluids contemporaneously with U mineralizing events. From 300 to 270 Ma, infiltration of surface-derived oxidized fluids leached magmatic uranium oxide from fertile leucogranite and formed U deposits. This phenomenon was sustained by brittle deformation and by the persistence of thermal anomalies associated with U-rich granitic bodies.

Actinide removal from spent salts

DOEpatents

Hsu, Peter C.; von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Adamson, Martyn G.

2002-01-01

A method for removing actinide contaminants (uranium and thorium) from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents are added to precipitate the thorium as thorium oxide and/or the uranium as either uranium oxide or as a diuranate salt. The precipitated materials are filtered, dried and packaged for disposal as radioactive waste. About 90% of the thorium and/or uranium present is removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 0.1 ppm of thorium or uranium.

Botanical prospecting for uranium on La Ventana Mesa, Sandoval County, New Mexico

USGS Publications Warehouse

Starrett, Wm. H.; Cannon, Helen L.

1954-01-01

A botanical sampling program has been completed by the U.S. Geological Survey on La Ventana Mesa, Sandoval County, N. Mex. A uranium-bearing coal in the Allison-Gibson members of the Cretaceous Mesaverde formation crops out in erosional remnants of the mesa.The coal is capped by a well-fractured 65-foot sandstone bed through which roots of a pinyon-juniper forest penetrate. Samples of several hundred branches of trees growing on top of the mesa were collected and analyzed for uranium. The assays ranged from 0.1 part per million to 2.3 ppm uranium in the wood ash. Dead branches, which were found to contain more uranium in the ash than live branches, were sampled where possible. The results have been contoured to indicated probable areas of mineralized coal. Parts of the north butte are recommended as favorable for physical exploration.

Efficient uranium capture by polysulfide/layered double hydroxide composites.

PubMed

Ma, Shulan; Huang, Lu; Ma, Lijiao; Shim, Yurina; Islam, Saiful M; Wang, Pengli; Zhao, Li-Dong; Wang, Shichao; Sun, Genban; Yang, Xiaojing; Kanatzidis, Mercouri G

2015-03-18

There is a need to develop highly selective and efficient materials for capturing uranium (normally as UO2(2+)) from nuclear waste and from seawater. We demonstrate the promising adsorption performance of S(x)-LDH composites (LDH is Mg/Al layered double hydroxide, [S(x)](2-) is polysulfide with x = 2, 4) for uranyl ions from a variety of aqueous solutions including seawater. We report high removal capacities (q(m) = 330 mg/g), large K(d)(U) values (10(4)-10(6) mL/g at 1-300 ppm U concentration), and high % removals (>95% at 1-100 ppm, or ∼80% for ppb level seawater) for UO2(2+) species. The S(x)-LDHs are exceptionally efficient for selectively and rapidly capturing UO2(2+) both at high (ppm) and trace (ppb) quantities from the U-containing water including seawater. The maximum adsorption coeffcient value K(d)(U) of 3.4 × 10(6) mL/g (using a V/m ratio of 1000 mL/g) observed is among the highest reported for U adsorbents. In the presence of very high concentrations of competitive ions such as Ca(2+)/Na(+), S(x)-LDH exhibits superior selectivity for UO2(2+), over previously reported sorbents. Under low U concentrations, (S4)(2-) coordinates to UO2(2+) forming anionic complexes retaining in the LDH gallery. At high U concentrations, (S4)(2-) binds to UO2(2+) to generate neutral UO2S4 salts outside the gallery, with NO3(-) entering the interlayer to form NO3-LDH. In the presence of high Cl(-) concentration, Cl(-) preferentially replaces [S4](2-) and intercalates into LDH. Detailed comparison of U removal efficiency of S(x)-LDH with various known sorbents is reported. The excellent uranium adsorption ability along with the environmentally safe, low-cost constituents points to the high potential of S(x)-LDH materials for selective uranium capture.

Macroporous monoliths for trace metal extraction from seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yue, Yanfeng; Mayes, Richard; Gill, Gary A.

2015-05-29

The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 μgL⁻¹). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N, N’-methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulated seawatermore » containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. The preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.« less

Alternative alkaline conditioning of amidoxime based adsorbent for uranium extraction from seawater

DOE PAGES

Das, Sadananda; Liao, Wei -Po; Byers, Maggie Flicker; ...

2015-10-18

Alkaline conditioning of the amidoxime based adsorbents is a significant step in the preparation of the adsorbent for uranium uptake from seawater. The effects of various alkaline conditioning parameters such as the type of alkaline reagent, reaction temperature, and reaction time were investigated with respect to uranium adsorption capacity from simulated seawater (spiked with 8 ppm uranium) and natural seawater (from Sequim Bay, WA). An adsorbent (AF1) was prepared at the Oak Ridge National Laboratory by radiation-induced graft polymerization (RIGP) with acrylonitrile and itaconic acid onto high-surface-area polyethylene fibers. For the AF1 adsorbent, sodium hydroxide emerged as a better reagentmore » for alkaline conditioning over potassium hydroxide, which has typically been used in previous studies, because of higher uranium uptake capacity and lower cost over the other candidate alkaline reagents investigated in this study. Furthermore, the use of sodium hydroxide in place of potassium hydroxide is shown to result in a 21–30% decrease in the cost of uranium recovery.« less

Macroporous monoliths for trace metal extraction from seawater

DOE PAGES

Yue, Yanfeng; Mayes, Richard T.; Gill, Gary; ...

2015-05-29

The viability of seawater-based uranium recovery depends on the uranium adsorption rate and capacity, since the concentration of uranium in the oceans is relatively low (3.3 gL -1). An important consideration for a fast adsorption is to maximize the adsorption properties of adsorbents such as surface areas and pore structures, which can greatly improve the kinetics of uranium extraction and the adsorption capacity simultaneously. Following this consideration, macroporous monolith adsorbents were prepared from the copolymerization of acrylonitrile (AN) and N,N -methylenebis(acrylamide) (MBAAm) based on a cryogel method using both hydrophobic and hydrophilic monomers. The monolithic sorbents were tested with simulatedmore » seawater containing a high uranyl concentration (–6 ppm) and the uranium adsorption results showed that the adsorption capacities are strongly influenced by the ratio of monomer to the crosslinker, i.e., the density of the amidoxime groups. Furthermore, the preliminary seawater testing indicates the high salinity content of seawater does not hinder the adsorption of uranium.« less

Alternative Alkaline Conditioning of Amidoxime Based Adsorbent for Uranium Extraction from Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Liao, W. -P.; Flicker Byers, M.

2016-04-20

Alkaline conditioning of the amidoxime based adsorbents is a significant step in the preparation of the adsorbent for uranium uptake from seawater. The effects of various alkaline conditioning parameters such as the type of alkaline reagent, reaction temperature, and reaction time were investigated with respect to uranium adsorption capacity from simulated seawater (spiked with 8 ppm uranium) and natural seawater (from Sequim Bay, WA). An adsorbent (AF1) was prepared at the Oak Ridge National Laboratory by radiation-induced graft polymerization (RIGP) with acrylonitrile and itaconic acid onto high-surface-area polyethylene fibers. For the AF1 adsorbent, sodium hydroxide emerged as a better reagentmore » for alkaline conditioning over potassium hydroxide, which has typically been used in previous studies, because of higher uranium uptake capacity and lower cost over the other candidate alkaline reagents investigated in this study. Use of sodium hydroxide in place of potassium hydroxide is shown to result in a 21-30% decrease in the cost of uranium recovery.« less

Alternative alkaline conditioning of amidoxime based adsorbent for uranium extraction from seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sadananda; Liao, Wei -Po; Byers, Maggie Flicker

Alkaline conditioning of the amidoxime based adsorbents is a significant step in the preparation of the adsorbent for uranium uptake from seawater. The effects of various alkaline conditioning parameters such as the type of alkaline reagent, reaction temperature, and reaction time were investigated with respect to uranium adsorption capacity from simulated seawater (spiked with 8 ppm uranium) and natural seawater (from Sequim Bay, WA). An adsorbent (AF1) was prepared at the Oak Ridge National Laboratory by radiation-induced graft polymerization (RIGP) with acrylonitrile and itaconic acid onto high-surface-area polyethylene fibers. For the AF1 adsorbent, sodium hydroxide emerged as a better reagentmore » for alkaline conditioning over potassium hydroxide, which has typically been used in previous studies, because of higher uranium uptake capacity and lower cost over the other candidate alkaline reagents investigated in this study. Furthermore, the use of sodium hydroxide in place of potassium hydroxide is shown to result in a 21–30% decrease in the cost of uranium recovery.« less

DPASV analytical technique for ppb level uranium analysis

NASA Astrophysics Data System (ADS)

Pal, Sangita; Singha, Mousumi; Meena, Sher Singh

2018-04-01

Determining uranium in ppb level is considered to be most crucial for reuse of water originated in nuclear industries at the time of decontamination of plant effluents generated during uranium (fuel) production, fuel rod fabrication, application in nuclear reactors and comparatively small amount of effluents obtained during laboratory research and developmental work. Higher level of uranium in percentage level can be analyzed through gravimetry, titration etc, whereas inductively coupled plasma-atomic energy spectroscopy (ICP-AES), fluorimeter are well suited for ppm level. For ppb level of uranium, inductively coupled plasma - mass spectroscopy (ICP-MS) or Differential Pulse Anodic Stripping Voltammetry (DPASV) serve the purpose. High precision, accuracy and sensitivity are the crucial for uranium analysis in trace (ppb) level, which are satisfied by ICP-MS and stripping voltammeter. Voltammeter has been found to be less expensive, requires low maintenance and is convenient for measuring uranium in presence of large number of other ions in the waste effluent. In this paper, necessity of uranium concentration quantification for recovery as well as safe disposal of plant effluent, working mechanism of voltammeter w.r.t. uranium analysis in ppb level with its standard deviation and a data comparison with ICP-MS has been represented.

Organic geochemical analysis of sedimentary organic matter associated with uranium

USGS Publications Warehouse

Leventhal, J.S.; Daws, T.A.; Frye, J.S.

1986-01-01

Samples of sedimentary organic matter from several geologic environments and ages which are enriched in uranium (56 ppm to 12%) have been characterized. The three analytical techniqyes used to study the samples were Rock-Eval pyrolysis, pyrolysis-gas chromatography-mass spectrometry, and solid-state C-13 nuclear magnetic resonance (NMR) spectroscopy. In samples with low uranium content, the pyrolysis-gas chromatography products contain oxygenated functional groups (as hydroxyl) and molecules with both aliphatic and aromatic carbon atoms. These samples with low uranium content give measurable Rock-Eval hydrocarbon and organic-CO2 yields, and C-13 NMR values of > 30% aliphatic carbon. In contrast, uranium-rich samples have few hydrocarbon pyrolysis products, increased Rock-Eval organic-CO2 contents and > 70% aromatic carbon contents from C-13 NMR. The increase in aromaticity and decrease in hydrocarbon pyrolysis yield are related to the amount of uranium and the age of the uranium minerals, which correspond to the degree of radiation damage. The three analytical techniques give complementary results. Increase in Rock-Eval organic-CO2 yield correlates with uranium content for samples from the Grants uranium region. Calculations show that the amount of organic-CO2 corresponds to the quantity of uranium chemically reduced by the organic matter for the Grants uranium region samples. ?? 1986.

Naturally Occurring Radioactive Materials in Uranium-Rich Coals and Associated Coal Combustion Residues from China.

PubMed

Lauer, Nancy; Vengosh, Avner; Dai, Shifeng

2017-11-21

Most coals in China have uranium concentrations up to 3 ppm, yet several coal deposits are known to be enriched in uranium. Naturally occurring radioactive materials (NORM) in these U-rich coals and associated coal combustion residues (CCRs) have not been well characterized. Here we measure NORM (Th, U, 228 Ra, 226 Ra, and 210 Pb) in coals from eight U-rich coal deposits in China and the associated CCRs from one of these deposits. We compared NORM in these U-rich coals and associated CCRs to CCRs collected from the Beijing area and natural loess sediments from northeastern China. We found elevated U concentrations (up to 476 ppm) that correspond to low 232 Th/ 238 U and 228 Ra/ 226 Ra activity ratios (≪1) in the coal samples. 226 Ra and 228 Ra activities correlate with 238 U and 232 Th activities, respectively, and 226 Ra activities correlate well with 210 Pb activities across all coal samples. We used measured NORM activities and ash yields in coals to model the activities of CCRs from all U-rich coals analyzed in this study. The activities of measured and modeled CCRs derived from U-rich coals exceed the standards for radiation in building materials, particularly for CCRs originating from coals with U > 10 ppm. Since beneficial use of high-U Chinese CCRs in building materials is not a suitable option, careful consideration needs to be taken to limit potential air and water contamination upon disposal of U- and Ra-rich CCRs.

40 CFR 1066.1001 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... a bag, such as PM and continuously measured THC. Bag 2 means relating to the last 867 seconds of the.... For hydrocarbon concentrations including HC, THC, NMHC, and NMOG, ppm means ppm on a C1-equivalent...

Reconnaissance for uranium and thorium in Alaska, 1954

USGS Publications Warehouse

Matzko, John J.; Bates, Robert G.

1957-01-01

During 1954 reconnaissance investigations to locate minable deposits of uranium and thorium in Alaska were unsuccessful. Areas examined, from which prospectors had submitted radioactive samples, include Cap Yakataga, Kodiak Island, and Shirley Lake. Unconcentrated gravels from the beach at Cape Yakataga average about 0.001 percent equivalent uranium. Uranothorianite has been identified by X-ray diffraction data and is the principal source of radioactivity in the Cape Yakataga beach sands studied; but the zircon, monazite, and uranothorite are also radioactive. The black, opaque uranothorianite generally occurs as minute euhedral cubs, the majority of which will pass through a 100-mesh screen. The bedrock source of the radioactive samples from Kodiak Island was not found; the maximum radioactivity of samples from the Shirley Lake area was equivalent to about 0.02 percent uranium. Radiometric traverses of the 460-foot level of the Garnet shaft of the Nixon Fork mine in the Nixon Fork mining district indicated a maximum of 0.15 mr/hr. In the Hot Springs district, drill hole concentrates of gravels examined contained a maximum of 0.03 percent equivalent uranium. A radioactivity anomaly noted during the Survey's airborne reconnaissance of portions of the Territory during 1954 is located in the Fairhaven district. A ground check disclosed that the radioactivity was due to accessory minerals in the granitic rock.

76 FR 60941 - Policy Regarding Submittal of Amendments for Processing of Equivalent Feed at Licensed Uranium...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-30

... State-licensed uranium recovery site, either conventional, heap leach, or in situ recovery. DATES... types of new uranium recovery facilities (conventional mills, heap leach facilities, and in situ... from the ground for processing at a mill. Rather, the ore is processed in-situ with the resulting...

Successful Coupling of a Bis-Amidoxime Uranophile with a Hydrophilic Backbone for Selective Uranium Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piechowicz, Marek; Abney, Carter W.; Thacker, Nathan C.

The amidoxime group (-RNH2NOH) has long been used to extract uranium from seawater on account of its high affinity toward uranium. The development of tunable sorbent materials for uranium sequestration remains a research priority as well as a significant challenge. Herein, we report the design, synthesis, and uranium sorption properties of bis-amidoxime-functionalized polymeric materials (BAP 1–3). Bifunctional amidoxime monomers were copolymerized with an acrylamide cross-linker to obtain bis-amidoxime incorporation as high as 2 mmol g–1 after five synthetic steps. The resulting sorbents were able to uptake nearly 600 mg of uranium per gram of polymer after 37 days of contactmore » with a seawater simulant containing 8 ppm uranium. Moreover, the polymeric materials exhibited low vanadium uptake with a maximum capacity of 128 mg of vanadium per gram of polymer. This computationally predicted and experimentally realized selectivity of uranium over vanadium, nearly 5 to 1 w/w, is one of the highest reported to date and represents an advancement in the rational design of sorbent materials with high uptake capacity and selectivity.« less

PROCESS OF RECOVERING URANIUM FROM ITS ORES

DOEpatents

Galvanek, P. Jr.

1959-02-24

A process is presented for recovering uranium from its ores. The crushed ore is mixed with 5 to 10% of sulfuric acid and added water to about 5 to 30% of the weight of the ore. This pugged material is cured for 2 to 3 hours at 100 to 110 deg C and then cooled. The cooled mass is nitrate-conditioned by mixing with a solution equivalent to 35 pounds of ammunium nitrate and 300 pounds of water per ton of ore. The resulting pulp containing 70% or more solids is treated by upflow percolation with a 5% solution of tributyl phosphate in kerosene at a rate equivalent to a residence time of about one hour to extract the solubilized uranium. The uranium is recovered from the pregnant organic liquid by counter-current washing with water. The organic extractant may be recycled. The uranium is removed from the water solution by treating with ammonia to precipitate ammonium diuranate. The filtrate from the last step may be recycled for the nitrate-conditioning treatment.

Facile Reductive Silylation of UO22+ to Uranium(IV) Chloride.

PubMed

Kiernicki, John J; Zeller, Matthias; Bart, Suzanne C

2017-01-19

General reductive silylation of the UO 2 2+ cation occurs readily in a one-pot, two-step stoichiometric reaction at room temperature to form uranium(IV) siloxides. Addition of two equivalents of an alkylating reagent to UO 2 X 2 (L) 2 (X=Cl, Br, I, OTf; L=triphenylphosphine oxide, 2,2'-bipyridyl) followed by two equivalents of a silyl (pseudo)halide, R 3 Si-X (R=aryl, alkyl, H; X=Cl, Br, I, OTf, SPh), cleanly affords (R 3 SiO) 2 UX 2 (L) 2 in high yields. Support is included for the key step in the process, reduction of U VI to U V . This procedure is applicable to a wide range of commercially available uranyl salts, silyl halides, and alkylating reagents. Under this protocol, one equivalent of SiCl 4 or two equivalents of Me 2 SiCl 2 results in direct conversion of the uranyl to uranium(IV) tetrachloride. Full spectroscopic and structural characterization of the siloxide products is reported. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gamma-ray spectrometry of granitic suites of the Paranaguá Terrane, Southern Brazil

NASA Astrophysics Data System (ADS)

Weihermann, Jessica Derkacz; Ferreira, Francisco José Fonseca; Cury, Leonardo Fadel; da Silveira, Claudinei Taborda

2016-09-01

The Paranaguá Terrane, located in the coastal portion of the states of Santa Catarina, Paraná and São Paulo in Southern Brazil is a crustal segment constituted mainly by an igneous complex, with a variety of granitic rocks inserted into the Serra do Mar ridge. The average altitude is approximately 1200 m above sea level, with peaks of up to 1800 m. Due to the difficulty of accessing the area, a shortage of outcrops and the thick weathering mantle, this terrane is understudied. This research aims to evaluate the gamma-ray spectrometry data of the granitic suites of the Paranaguá Terrane, in correspondence with the geological, petrographical, lithogeochemical, relief and mass movement information available in the literature. Aerogeophysical data were acquired along north-south lines spaced at 500 m, with a mean terrain clearance of 100 m. These data cover potassium (K, %), equivalent in thorium (eTh, ppm) and equivalent in uranium (eU, ppm). After performing a critical analysis of the data, basic (K, eU, eTh) and ternary (R-K/G-eTh/B-eU) maps were generated and then superimposed on the digital elevation model (DEM). The investigation of the radionuclide mobility across the relief and weathering mantle consisted of an analysis of the schematic profiles of elevation related with each radionuclide; a comparison of the K, eU and eTh maps with their 3D correspondents; and the study of mass movements registered in the region. A statistical comparison of lithogeochemical (K, U, Th) and geophysical (K, eU, eTh) data showed consistency in all the granitic suites studied (Morro Inglês, Rio do Poço and Canavieiras-Estrela). Through gamma-ray spectrometry, it was possible to establish relationships between scars (from mass movements) and the gamma-ray responses as well as the radionuclide mobility and the relief and to map the granitic bodies.

Screening level model for ecological risk assessment at EF-Site Los Alamos National Laboratory, New Mexico. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alldredge, A.W.; Kirchner, T.B.; McLendon, T.

1995-12-01

In response to a paucity of data on the chemical toxicity of uranium to plants, a factorial experiment employing five uranium concentrations (0, 50, 500, 5000, 25000 ppm) and three moisture regimes (low, medium, high) was performed using three native grasses. Buchloe dactyloides (buffalograss-mid/late seral), Schizachyrium scoparium (little bluestem-late seral), and Aristida longiseta (purple threeawn-early/mid seral) were grown in monocultures and every mixture of two species under all combinations of uranium and moisture levels. This design allows for the analysis of uranium effects, as well as possible compound effects due to moisture stress. Several measures of plant health and viabilitymore » were made, including: percent emergence, survivability of seedlings and mature plants, root and shoot biomass, and the number and mass of inflorescences. No significant differences between uranium levels were observed in terms of emergence and seedling survival. Effects are evident for plant biomass, fecundity, and long-term survivability.« less

PROGRESS ON THE STUDY OF THE URANIUM-ALUMINUM-IRON CONSTITUTION DIAGRAM FOR THE PERIOD SEPTEMBER 1-DECEMBER 31, 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, R.B.

The U--Al--Fe constitution diagram up to about 1000 ppm each of aluminum and iron is sthdied. The techniques used for this study include optical, electron, and x-ray metallography; microprobe analysis, electric conductivity, and hardness measurements. A combination of techniques are giving evidence of the amount of solid solubility of aluminum and iron in alpha, beta, and gamma uranium at selected higher temperatures. The U-Al and U-Fe phase diagrams are also being determined. (N.W.R.)

TRACE ELEMENT ANALYSES OF URANIUM MATERIALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beals, D; Charles Shick, C

The Savannah River National Laboratory (SRNL) has developed an analytical method to measure many trace elements in a variety of uranium materials at the high part-per-billion (ppb) to low part-per-million (ppm) levels using matrix removal and analysis by quadrapole ICP-MS. Over 35 elements were measured in uranium oxides, acetate, ore and metal. Replicate analyses of samples did provide precise results however none of the materials was certified for trace element content thus no measure of the accuracy could be made. The DOE New Brunswick Laboratory (NBL) does provide a Certified Reference Material (CRM) that has provisional values for a seriesmore » of trace elements. The NBL CRM were purchased and analyzed to determine the accuracy of the method for the analysis of trace elements in uranium oxide. These results are presented and discussed in the following paper.« less

Uranium in the Mayoworth area, Johnson County, Wyoming - a preliminary report

USGS Publications Warehouse

Love, J.D.

1954-01-01

The uranium mineral, metatyuyamunite, occurs in the basal limestone of the Sundance formation of late Jurassic age along the east flank of the Bighorn Mountains, about 2 miles southwest of the abandoned Mayoworth post office. This occurrence is of particular interest because it is the first uranium mineralization reported from a marine limestone in Wyoming. The discovery uranium claims were filed in July 1953, by J.S. Masek, Dan Oglesby, and Jack Emery of Casper, Wyo. Subsequent reconnaissance investigations have been made by private individuals and geologists of the U.S. Geological Survey and Atomic Energy Commission. The metatyuyamunite is concentrated in a hard gray oolitic limestone that forms the basal bed of the Sundance formation. A selected sample of limestone from a fresh face in the northernmost deposit known at the time of the field examination contained 0.70 percent equivalent uranium and 0.71 percent uranium. Eight samples of the limestone taken at the sample place by the Atomic Energy Commission contained from 0.007 to 0.22 percent uranium. A chip sample from the weathered outcrop at the top of this limestone half a mile to the southeast contained 0.17 percent equivalent uranium and 0.030 percent uranium. A dinosaur bone from the middle part of the Morrison formation contained 0.044 percent equivalent uranium and 0.004 percent uranium. metatyuyamunite forms a conspicuous yellow coating along fracture planes cutting the oolitic limestone and has also replaced many of the oolites within the solid limestone and has also replaced many of the oolites within the solid limestone even where fractures are not present. Many radioactive spots in the basal limestone of the Sundance formation were examined in a reconnaissance fashion along the outcrop for a distance of half a mile south of the initial discovery. Samples were taken for analysis only at the northern and southern margins of this interval. Outcrops farther north and south were not studied. There are not sufficient data to make even rough estimates of tonnage and grade of the occurrences. The extent of the limestone, the approximate boundaries of the area of above-normal radioactivity, and the possibilities of other radioactive zones have not been thoroughly investigated. Although dinosaur bones in the Morrison formation were radioactive wherever they were tested, no significant amount of radioactivity was observed in rocks adjacent to the bones.

Subpart B: National Emission Standards for Radon Emissions From Underground Uranium Mines

EPA Pesticide Factsheets

Subpart B sets a limit on the emission of radon-222 that ensures that no member of the public in any year receives an effective dose equivalent of more than 10 mrem/year from an underground uranium mine.

Preliminary study of radioactive limonite localities in Colorado, Utah, and Wyoming

USGS Publications Warehouse

Lovering, T.G.; Beroni, E.P.

1956-01-01

Nine radioactive limonite localities of different types were sampled during the spring and fall of 1953 in an effort to establish criteria for differentiating limonite outcrops associated with uranium or thorium deposits from limonite outcrops not associated with such deposits. The samples were analyzed for uranium and thorium by standard chemical methods, for equivalent uranium by the radiometric method, and for a number of common metals by semiquantitative geochemical methods. Correlation coefficients were then calculated for each of the metals with respect to equivalent uranium, and to uranium where present, for all of the samples from each locality. The correlation coefficients may indicate a significant association between uranium or thorium and certain metals. Occurrences of specific that are interpreted as significant very considerably for different uranium localities but are more consistent for the thorium localities. Samples taken from radioactive outcrops in the vicinity of uranium or thorium deposits can be quickly analyzed by geochemical methods for various elements. Correlation coefficients can then be determined for the various elements with respect to uranium or thorium; if any significant correlations are obtained, the elements showing such correlation may be indicators of uranium or thorium. Soil samples of covered areas in the vicinity of the radioactive outcrop may then be analyzed for the indicator elements and any resulting anomalies used as a guide for prospecting where the depth of overburden is too great to allow the use of radiation-detecting instruments. Correlation coefficients of the associated indicator elements, used in conjunction with petrographic evidence, may also be useful in interpreting the origin and paragenesis of radioactive deposits. Changes in color of limonite stains on the outcrop may also be a useful guide to ore in some areas.

75 FR 53581 - Spiromesifen; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-01

... regulation establishes tolerances for residues of spiromesifen in or on leaf petioles subgroup 4B, dry pea... equivalents, in or on pea, dry, seed at 0.15 parts per million (ppm); spearmint, tops at 25 ppm; and... for tolerances levels different from those proposed in the petitions for dry pea seed, spearmint tops...

A record of uranium-series transport at Nopal I, Sierra Pena Blanca, Mexico: Implications for natural uranium deposits and radioactive waste repositories

DOE PAGES

Denton, J. S.; Goldstein, S. J.; Paviet, P.; ...

2016-04-10

Studies of uranium-series (U-series) disequilibria within and around ore deposits provide valuable information on the extent and timing of actinide mobility, via mineral-fluid interaction, over a range of spatial and temporal scales. Such information is useful in studies of analogs of high-level nuclear-waste repositories, as well as for mining and mineral extraction sites, locations of previous nuclear weapons testing, and legacy nuclear waste contamination. In this study we present isotope dilution mass spectrometry U-series measurements for fracture-fill materials (hematite, goethite, kaolinite, calcite, dolomite and quartz) from one such analog; the Nopal I uranium ore deposit situated at Peña Blanca inmore » the Chihuahua region of northern Mexico. The ore deposit is located in fractured, unsaturated volcanic tuff and fracture-fill materials from surface fractures as well as fractures in a vertical drill core have been analyzed. High uranium concentrations in the fracture-fill materials (between 12 and 7700 ppm) indicate uranium mobility and transport from the deposit. Furthermore, uranium concentrations generally decrease with horizontal distance away from the deposit but in this deposit there is no trend with depth below the surface.« less

Radioactive equilibrium in ancient marine sediments

USGS Publications Warehouse

Breger, I.A.

1955-01-01

Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent-indicating that there is probably equilibrium in all the formations analyzed. Thick-source alpha-particle counting by means of a proportional counter or an ionization chamber leads to high results when the samples contain less than about 10 p.p.m. of uranium. For samples having a higher content of uranium the results are in excellent agreement with each other and with those obtained by direct analytical techniques. The thorium contents that have been obtained correspond well to the average values reported in the literature. The uranium content of marine sediments may be appreciably higher than the average values that have been reported for sedimentary rocks. Data show that there is up to fourteen times the percentage of uranium as of thorium in the formations studied and that the percentage of thorium never exceeds that of uranium. While the proximity of a depositional environment to a land mass may influence the concentration of uranium in a marine sediment, this is not true with thorium. ?? 1955.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuzmina, L.A.

A method has been developed for determining uranium, thorium, and ionium (Th/sup 230/) in sea silt from a single sample. The completeness of isolation and radiochemical purity of thorium isotopes have been tested by means of tracers. The method has been proved on samples of sea silt as well as of rocks, ores, and minerals. It is applicable at thorium content from 5 x 10/sup -5/ to x x 10/sup - 4/% when uranium content is x x 10/sup -4/ % and at uranium content up to 70% when ionium contert is x x 10/sup -4/% (uranium equivalent). (tr-auth)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denton, J. S.; Goldstein, S. J.; Paviet, P.

Studies of uranium-series (U-series) disequilibria within and around ore deposits provide valuable information on the extent and timing of actinide mobility, via mineral-fluid interaction, over a range of spatial and temporal scales. Such information is useful in studies of analogs of high-level nuclear-waste repositories, as well as for mining and mineral extraction sites, locations of previous nuclear weapons testing, and legacy nuclear waste contamination. In this study we present isotope dilution mass spectrometry U-series measurements for fracture-fill materials (hematite, goethite, kaolinite, calcite, dolomite and quartz) from one such analog; the Nopal I uranium ore deposit situated at Peña Blanca inmore » the Chihuahua region of northern Mexico. The ore deposit is located in fractured, unsaturated volcanic tuff and fracture-fill materials from surface fractures as well as fractures in a vertical drill core have been analyzed. High uranium concentrations in the fracture-fill materials (between 12 and 7700 ppm) indicate uranium mobility and transport from the deposit. Furthermore, uranium concentrations generally decrease with horizontal distance away from the deposit but in this deposit there is no trend with depth below the surface.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bromfield, C.S.; Grauch, R.I.; Otton, J.K.

The Richfield Quadrangle in west-central Utah was evaluated to identify areas favorable for the occurrence of uranium deposits known or likely to contain 100 tons of uranium with an average grade of not less than 100 ppM U/sub 3/O/sub 8/. Geologic reconnaissance was made of all known environments thought to be favorable for uranium deposits, and a representative selection of uranium occurrences reported in the literature was visited. Geochemical analyses from rock and limited water samples were used in the evaluation. Preliminary and incomplete aeroradiometric data and hydrogeochemical and stream-sediment analyses arrived too late in the program to be field-checkedmore » or to be adequately analyzed for this report. Two areas favorable for uranium deposits were delineated: (1) volcanogenic deposits (class 500 to 599) in association with Miocene Mount Belknap rhyolite, and acidic plutons in the Marysvale Volcanic Field in the Antelope Range and Tushar Mountains; and (2) volcanogenic (class 500 to 599) and/or magmatic hydrothermal deposits (class 330) associated with Miocene high-silica high-alkali rhyolite tuffs, flows, and hypabyssal intrusives in volcanic or subvolcanic environments in the southern Wah Wah Mountains.« less

Uraniferous opal, Virgin Valley, Nevada: conditions of formation and implications for uranium exploration

USGS Publications Warehouse

Zielinski, R.A.

1982-01-01

Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5-20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal. ?? 1982.

National Uranium Resource Evaluation. Volume 1. Summary of the geology and uranium potential of Precambrian conglomerates in southeastern Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karlstrom, K.E.; Houston, R.S.; Flurkey, A.J.

1981-02-01

A series of uranium-, thorium-, and gold-bearing conglomerates in Late Archean and Early Proterozoic metasedimentary rocks have been discovered in southern Wyoming. The mineral deposits were found by applying the time and strata bound model for the origin of uranium-bearing quartz-pebble conglomerates to favorable rock types within a geologic terrane known from prior regional mapping. No mineral deposits have been discovered that are of current (1981) economic interest, but preliminary resource estimates indicate that over 3418 tons of uranium and over 1996 tons of thorium are present in the Medicine Bow Mountains and that over 440 tons of uranium andmore » 6350 tons of thorium are present in Sierra Madre. Sampling has been inadequate to determine gold resources. High grade uranium deposits have not been detected by work to date but local beds of uranium-bearing conglomerate contain as much as 1380 ppM uranium over a thickness of 0.65 meters. This project has involved geologic mapping at scales from 1/6000 to 1/50,000 detailed sampling, and the evaluation of 48 diamond drill holes, but the area is too large to fully establish the economic potential with the present information. This first volume summarizes the geologic setting and geologic and geochemical characteristics of the uranium-bearing conglomerates. Volume 2 contains supporting geochemical data, lithologic logs from 48 drill holes in Precambrian rocks, and drill site geologic maps and cross-sections from most of the holes. Volume 3 is a geostatistical resource estimate of uranium and thorium in quartz-pebble conglomerates.« less

Extracting uranium from seawater: Promising AI series adsorbents

DOE PAGES

Das, Sadananda; Oyola, Y.; Mayes, Richard T.; ...

2015-11-10

A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged frommore » 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.« less

Extracting uranium from seawater: Promising AI series adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sadananda; Oyola, Y.; Mayes, Richard T.

A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged frommore » 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.« less

Extracting Uranium from Seawater: Promising AI Series Adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Oyola, Y.; Mayes, R. T.

A new series of adsorbents (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole to mole ratios) onto high surface area polyethylene fiber, with high degrees of grafting (DOG) varying from 110 to 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 5 wt % hydroxylamine at 80 °C for 72 h. The amidoximated adsorbents were then conditioned with 0.44 M KOH at 80 °C followed by screening at ORNL with prescreening brine spiked with 8 ppm uranium. Uranium adsorption capacitiesmore » in prescreening ranged from 171 to 187 g-U/kg-ads irrespective of percent DOG. The performance of the adsorbents with respect to uranium adsorption in natural seawater was also investigated using flow-throughcolumn testing at the Pacific Northwest National Laboratory (PNNL). Three hours of KOH conditioning led to higher uranium uptake than 1 h of conditioning. The adsorbent AI11, containing AN and VPA at the mole ratio of 3.52, emerged as the potential candidate for the highest uranium adsorption (3.35 g-U/kg-ads.) after 56 days of exposure in seawater flow-through-columns. The rate of vanadium adsorption over uranium linearly increased throughout the 56 days of exposure. The total mass of vanadium uptake was ~5 times greater than uranium after 56 days.« less

Renewable Energy Capability vs. Climate Necessity

ERIC Educational Resources Information Center

Mills, David

2006-01-01

A 450-ppm equivalent CO[2] target by 2050 is an often-proposed goal under a future global emissions agreement, but there is considerable high side risk in global-warming models due to cloud formation, feedbacks in dissolved organic carbon from peat bogs in polar regions, and unaccounted solar dimming by particulates. The 450-ppm figure is…

Hydrogeochemical and stream sediment reconnaissance basic data report for Williams NTMS quadrangle, Arizona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagoner, J.L.

Wet and dry sediments were collected throughout the 18,500-km/sup 2/arid-to-semiarid region and water samples at available streams, springs, and wells. Samples were collected between August 1977 and January 1978. Results of neutron activation analyses of uranium and trace elements and other field and laboratory analyses are presented in tabular hardcopy and microfiche format. The report includes six full-size overlays for use with the Williams NTMS 1:250,000 quadrangle. Sediment samples are divided into five general groups according to the source rock from which the sediment was derived. Background uranium concentrations for the quadrangle are relatively low, ranging from 1.91 to 2.40more » ppM, with the highest associated with the Precambrian igneous and metamorphic complexes of the Basin and Range province. Uranium correlates best with the rare-earth elements and iron, scandium, titanium, and manganese. Known uranium occurrences are not readily identified by the stream sediment data.« less

Incorporation of Uranium into Hematite during Crystallization from Ferrihydrite

PubMed Central

2014-01-01

Ferrihydrite was exposed to U(VI)-containing cement leachate (pH 10.5) and aged to induce crystallization of hematite. A combination of chemical extractions, TEM, and XAS techniques provided the first evidence that adsorbed U(VI) (≈3000 ppm) was incorporated into hematite during ferrihydrite aggregation and the early stages of crystallization, with continued uptake occurring during hematite ripening. Analysis of EXAFS and XANES data indicated that the U(VI) was incorporated into a distorted, octahedrally coordinated site replacing Fe(III). Fitting of the EXAFS showed the uranyl bonds lengthened from 1.81 to 1.87 Å, in contrast to previous studies that have suggested that the uranyl bond is lost altogether upon incorporation into hematite. The results of this study both provide a new mechanistic understanding of uranium incorporation into hematite and define the nature of the bonding environment of uranium within the mineral structure. Immobilization of U(VI) by incorporation into hematite has clear and important implications for limiting uranium migration in natural and engineered environments. PMID:24580024

Weathering and evaporation controls on dissolved uranium concentrations in groundwater - A case study from northern Burundi.

PubMed

Post, V E A; Vassolo, S I; Tiberghien, C; Baranyikwa, D; Miburo, D

2017-12-31

The potential use of groundwater for potable water supply can be severely compromised by natural contaminants such as uranium. The environmental mobility of uranium depends on a suite of factors including aquifer lithology, redox conditions, complexing agents, and hydrological processes. Uranium concentrations of up to 734μg/L are found in groundwater in northern Burundi, and the objective of the present study was to identify the causes for these elevated concentrations. Based on a comprehensive data set of groundwater chemistry, geology, and hydrological measurements, it was found that the highest dissolved uranium concentrations in groundwater occur near the shores of Lake Tshohoha South and other smaller lakes nearby. A model is proposed in which weathering and evapotranspiration during groundwater recharge, flow and discharge exert the dominant controls on the groundwater chemical composition. Results of PHREEQC simulations quantitatively confirm this conceptual model and show that uranium mobilization followed by evapo-concentration is the most likely explanation for the high dissolved uranium concentrations observed. The uranium source is the granitic sand, which was found to have a mean elemental uranium content of 14ppm, but the exact mobilization process could not be established. Uranium concentrations may further be controlled by adsorption, especially where calcium-uranyl‑carbonate complexes are present. Water and uranium mass balance calculations for Lake Tshohoha South are consistent with the inferred fluxes and show that high‑uranium groundwater represents only a minor fraction of the overall water input to the lake. These findings highlight that the evaporation effects that cause radionuclide concentrations to rise to harmful levels in groundwater discharge areas are not only confined to arid regions, and that this should be considered when selecting suitable locations for water supply wells. Copyright © 2017 Elsevier B.V. All rights reserved.

Deposit model for volcanogenic uranium deposits

USGS Publications Warehouse

Breit, George N.; Hall, Susan M.

2011-01-01

The International Atomic Energy Agency's tabulation of volcanogenic uranium deposits lists 100 deposits in 20 countries, with major deposits in Russia, Mongolia, and China. Collectively these deposits are estimated to contain uranium resources of approximately 500,000 tons of uranium, which amounts to 6 percent of the known global resources. Prior to the 1990s, these deposits were considered to be small (less than 10,000 tons of uranium) with relatively low to moderate grades (0.05 to 0.2 weight percent of uranium). Recent availability of information on volcanogenic uranium deposits in Asia highlighted the large resource potential of this deposit type. For example, the Streltsovskoye district in eastern Russia produced more than 100,000 tons of uranium as of 2005; with equivalent resources remaining. Known volcanogenic uranium deposits within the United States are located in Idaho, Nevada, Oregon, and Utah. These deposits produced an estimated total of 800 tons of uranium during mining from the 1950s through the 1970s and have known resources of 30,000 tons of uranium. The most recent estimate of speculative resources proposed an endowment of 200,000 tons of uranium.

THE ACCURATE DETERMINATION OF MICROGRAM AMOUNTS OF BORON IN ALUMINUM AND ALUMINUM-URANIUM ALLOYS BY THE METHYL BORATE-CURCUMIN-OXALIC ACID METHOD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crocker, I.H.

1958-10-01

A method was developed for the deternninntion of boron in aluminum and aluminum--uranium alloys in which the boron concentration is 30 ppm or more. Boron is separated by distillation as methyl borate from a hydrochloric acid solution of the alloy and is determined spectrophotometrically by the boric acid-- curcumin-oxalic acid color reaction. A precision of plus or minus 2% is attain able when the determination is penformed with the utmost care. The accuracy is such that no bias need be given when a calibration curve is used. (auth)

Uranium in granitic magmas: Part 2. Experimental determination of uranium solubility and fluid-melt partition coefficients in the uranium oxide-haplogranite-H 2O-NaX (X = Cl, F) system at 770°C, 2 kbar

NASA Astrophysics Data System (ADS)

Peiffert, Chantal; nguyen-Trung, Chinh; Cuney, Michel

1996-05-01

The solubility of uranium oxide was investigated in both aqueous halide (Cl, F) fluid and granitic melt in equilibrium in the system uranium oxide-haplogranite-H 2O-NaCl (0.1-5.0 molal), NaF (0.1-0.5 molal) at 770°C, 2 kbar, and fO 2 conditions controlled by Ni-NiO, Fe 3O 4-Fe 2O 3, and Cu 2O- CuO buffers. Three distinct uranium oxides UO (2+ x) with x = 0.01 ± 0.01; 0.12 ± 0.02; and 0.28 ± 0.02, respec- tively, were obtained in both chloride and fluoride systems, under the three fO 2 conditions cited above. Changes in the composition of aqueous solutions and silicate melt were observed after the runs. These changes were more pronounced for the fluoride-bearing experiments. Quench pH decreased from 5.9 to 2.1 with increasing chloride molality from 0.085-4.38 molal. For fluoride solutions, the decrease of pH from 5.4 to 3.4 corresponded to the increase of fluoride molality from 0.02-0.23 molal. The U solubility in chloride solutions was in the range 10-967 ppm. For the same molality, fluoride solutions appeared to dissolve up to twenty times more uranium than chloride solutions. The increase of halide molality and oxidation led to increase the U solubility. The U solubility in silicate glasses was in the range 10-1.8 × 10 4 ppm and increased with increasing oxidation and halide concentration. In addition, increasing agpaicity also increased U solubility in the chloride system. This effect was not observed in the fluoride system. The chloride concentration in the silicate melt increased from 100-790 ppm with increasing initial aqueous chloride concentration from 0.1-5.0 m. The fluoride concentration in the silicate melt increased from 2.8 × 10 3 to 1.1 × 10 4 ppm with increasing initial fluoride concentra- tion from 0.1-0.5 m. In the chloride system, the partition coefficient of U (log D)(U) fluid/melt) increased from -1.2-0 with increasing agpaicity from 0.92-1.36, for increasing chloride concentration from 0.085-4.38 molal and for increasing fO 2 from 10 -15 to 10 -4 bar. In the fluoride system, a linear correlation was established between the partition coefficient of U and the log fO 2. In F-rich system, D(U) fluid/melt values was in the range 2.4 × 10 -2-4.2 × 10 -2 for increasing fluoride concentration from 0.02-0.22 molal and for the same increasing of fO 2. In the chloride system, the partition coefficients of Na ( D (Na) fluid/melt) and K ( D) (K) fluid/melt) are in good agreement up to 1.0 m NaCl with the two linear equations established by Holland (1972) : D (Na) fluid/melt = 0.46 × (Cl)(m) (1) and D(Na) fluid/melt = 0.34 × (Cl)(m) (2). However, in initial 5.0 m NaCl, slopes of Eqns. 1 and 2 decreased to 0.41 and 0.16, respectively. Data obtained in the present study provide useful information for the understanding of the behaviour of U in the fractionation processes of halide rich magmas. Fluid/melt partition coefficients higher than one, favorable for the genesis of magmatic U mineralization, can be reached for peraluminous leucogran- ites in equilibrium with chloride-rich solutions.

A study of contaminated soils near Crucea-Botus, ana uranium mine (East Carpathians, Romania): metal distribution and partitioning of natural actinides with implications for vegetation uptake

NASA Astrophysics Data System (ADS)

Petrescu, L.; Bilal, E.

2012-04-01

Between 1962 and 2009, National Company of Uranium - CNU, the former Romanian Rare Metals Mining Company, mined over 1,200,000 tones of pitchblende ore in the East Carpathians (Crucea-Botušana area, Bistrita Mountains). The exploration and mining facilities include 32 adits, situated between 780 and 1040 m above sea level. Radioactive waste resulted from mining are disposed next to the mining facilities. Mine dumps (32) cover an area of 364,000 square meters and consist of waste rock (rocks with sub-economic mineralization) and gangue minerals. Older dumps (18) have been already naturally reclaimed by forest vegetation, which played an important role in stabilizing the waste dump cover and in slowing down the uranium migration processes. The soils samples have been collected from different mine dumps in the Crucea-Botušana uranium deposit, mainly from 1, 4, 5, 6, 8, 9, 1/30 and 950 mine waste galleries. Soil samples were collected from the upper part and slope at each mine dump, from the vegetation root zones. Total uranium concentration in soils collected from Crucea-Botušana site ranged from 6.10 to 680.70 ppm, with a mean of 52.48 ppm (dry wt.). Total thorium varies between 7.70 and 115.30 ppm (dry wt.). This indicates that the adsorption of the radioactive elements by the soils is high and variable, influenced by the ore dump - sample relationship. The sequential extraction has emphasized the fact that the uranium is associated with all the mineral fractions present in the soil samples. A great percentage of U can be found in the carbonate (21.77%), organic (15.04%) and oxides fractions (15.88%) - in accordance with the high absorbed/adsorbed properties of this element. The percentage of uranium detected in the exchangeable fraction is rather small - 2.16%. It is also to be expected that the uranium should be irreversible adsorbed by the organic matter and by the clay minerals due to its ionic radius and to its positive charge. The fact that 21.77% of the total uranium can be found in the specifically absorbed and carbonate bound fraction, indicated the important role played by the carbonates in the retention of U; one the other hand this fraction is liable to release the uranium if the pH should happen to change. Thorium appear in high-enough concentration in the soil is scarcely available because 70.29% is present in residual fraction, and about 21.78% in the crystalline iron oxides occluded fraction and organically and secondary sulfide bound fraction. This is certainly due to the fact that this naturally occurring radionuclide can be associated with relatively insoluble mineral phases like alumino-silicates and refractory oxides. Its association with the organic matter (10.93%) suggests that it can form soluble organic complexes that can facilitate its removal by the stream waters. Grounded on these results, we were able to prove that the examined mine dumps can represent an impact on the environment, which constitute an argument in favor of the initiation of a program of remedying the quality of the environment from this mining zone. Although from our research it resulted that the natural actinides does not concentrate in the exchangeable fraction (Th) or it concentrates very little in it (U), the isolation of the mineral fraction of soil rich in U and Th helps us in the future identification of the links between the bioavailability and the pedogenesis, connections which control the cycle of the radioactive metals.

Middle Proterozoic age for the Montpelier Anorthosite, Goochland terrane, eastern Piedmont, Virginia

USGS Publications Warehouse

Aleinikoff, J.N.; Horton, J. Wright; Walter, M.

1996-01-01

Uranium-lead dating of zircons from the Montpelier Anorthosite confirms previous interpretations, based on equivocal evidence, that the Goochland terrane in the eastern Piedmont of Virginia contains Grenvillian basement rocks of Middle Proterozoic age. A very few prismatic, elongate, euhedral zircons, which contain 12-29 ppm uranium, are interpreted to be igneous in origin. The vast majority of zircons are more equant, subangular to anhedral, contain 38-52 ppm uranium, and are interpreted to be metamorphic in origin. One fraction of elongate zircon, and four fragments of a very large zircon (occurring in a nelsonite segregation) yield an upper intercept age of 1045 ?? 10 Ma, interpreted as the time of anorthosite crystallization. Irregularly shaped metamorphic zircons are dated at 1011 ?? 2 Ma (weighted average of the 207Pb/206Pb ages). The U-Pb isotopic systematics of metamorphic titanite were reset during the Alleghanian orogeny at 297 ?? 5 Ma. These data provide a minimum age for gneisses of the Goochland terrane that are intruded by the anorthosite. Middle Proterozoic basement rocks of the Goochland terrane may be correlative with those in the Shenandoah massif of the Blue Ridge tectonic province, as suggested by similarities between the Montpelier Anorthosite and the Roseland anorthosite. Although the areal extent of Middle Proterozoic basement and basement-cover relations in the eastern Piedmont remain unresolved, results of this investigation indicate that the Goochland terrane is an internal massif of Laurentian crust rather than an exotic accreted terrane.

The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour.

PubMed

Scott, T B; Petherbridge, J R; Harker, N J; Ball, R J; Heard, P J; Glascott, J; Allen, G C

2011-11-15

The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO(3) · xH(2)O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Molecular marker and stable carbon isotope analyses of carbonaceous Ambassador uranium ores of Mulga Rock in Western Australia

NASA Astrophysics Data System (ADS)

Jaraula, C.; Schwark, L.; Moreau, X.; Grice, K.; Bagas, L.

2013-12-01

Mulga Rock is a multi-element deposit containing uranium hosted by Eocene peats and lignites deposited in inset valleys incised into Permian rocks of the Gunbarrel Basin and Precambrian rocks of the Yilgarn Craton and Albany-Fraser Orogen. Uranium readily adsorbs onto minerals or phytoclasts to form organo-uranyl complexes. This is important in pre-concentrating uranium in this relatively young ore deposit with rare uraninite [UO2] and coffinite [U(SiO4)1-x(OH)4x], more commonly amorphous and sub-micron uranium-bearing particulates. Organic geochemical and compound-specific stable carbon isotope analyses were conducted to identify possible associations of molecular markers with uranium accumulation and to recognize effect(s) of ionizing radiation on molecular markers. Samples were collected from the Ambassador deposit containing low (<200 ppm) to high (>2000 ppm) uranium concentrations. The bulk rock C/N ratios of 82 to 153, Rock-Eval pyrolysis yields of 316 to 577 mg hydrocarbon/g TOC (Hydrogen Index, HI) and 70 to 102 mg CO2/g TOC (Oxygen Index, OI) are consistent with a terrigenous and predominantly vascular plant OM source deposited in a complex shallow water system, ranging from lacustrine to deltaic, swampy wetland and even shallow lake settings as proposed by previous workers. Organic solvent extracts were separated into saturated hydrocarbon, aromatic hydrocarbon, ketone, and a combined free fatty acid and alcohol fraction. The molecular profiles appear to vary with uranium concentration. In samples with relatively low uranium concentrations, long-chain n-alkanes, alcohols and fatty acids derived from epicuticular plant waxes dominate. The n-alkane distributions (C27 to C31) reveal an odd/even preference (Carbon Preference Index, CPI=1.5) indicative of extant lipids. Average δ13C of -27 to -29 ‰ for long-chain n-alkanes is consistent with a predominant C3 plant source. Samples with relatively higher uranium concentrations contain mostly intermediate-length n-alkanes, ketones, alcohols, and fatty acids (C20 to C24) with no preferential distribution (CPI~1). Intermediate length n-alkanes have modest carbon isotope enrichment compared to long-chain n-alkanes. These shorter-chain hydrocarbons are interpreted to represent alteration products. The diversity and relative abundance of ketones in highly mineralised Mulga Rock peats and lignites are not consistent with aerobic and diagenetic degradation of terrigenous OM in oxic environments. Moreover, molecular changes cannot be associated with thermal breakdown due to the low maturity of the deposits. It is possible that the association of high uranium concentrations and potential radiolysis resulted in the oxidation of alcohol functional groups into aldehydes and ketones and breakdown of highly aliphatic macromolecules (i.e. spores, pollen, cuticles, and algal cysts). These phytoclasts are usually considered to be recalcitrant as they evolved to withstand chemical and physical degradation. Previous petrographic analyses show that spores, pollen and wood fragments are preferentially enriched in uranium. Their molecular compositions are feasible sources of short- to intermediate-length n-alkanes that dominate the mineralised peats and lignites.

40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.

Code of Federal Regulations, 2011 CFR

2011-07-01

... basis and analyzes the samples with gas chromatography or, if the owner or operator assumes that all... concentration of vinyl chloride in the exhaust gases does not exceed 10 ppm (average for 3-hour period), or... chloride in the exhaust gases does not exceed 10 ppm (average for 3-hour period), or equivalent as provided...

Field determination of microgram quantities of niobium in rocks

USGS Publications Warehouse

Ward, F.N.; Marranzino, A.P.

1955-01-01

A rapid, simple, and moderately accurate method was needed for the determination of traces of niobium in rocks. The method developed is based on the reaction of niobium(V) with thiocyanate ion in a 4M hydrochloric acid and 0.5M tartaric acid medium, after which the complex is extracted with ethyl ether. The proposed procedure is applicable to rocks containing from 50 to 2000 p.p.m. of niobium, and, with modifications, can be used on rocks containing larger amounts. Five determinations on two rocks containing 100 p.p.m. or less of niobium agree within 5 p.p.m. of the mean, and the confidence limits at the 95% level are, respectively, ??6 and ??4 p.p.m. The addition of acetone to the ether extract of the niobium thiocyanate inhibits the polymerization of the thiocyanate ion and stabilizes the solution for at least 20 hours. The proposed procedure permits the determination of 20 ?? of niobium in the presence of 1000 ?? of iron, titanium, or uranium; 500 ?? of vanadium; or 100 ?? of tungsten or molybdenum or both.

Hydrogeochemical and stream sediment detailed geochemical survey for Edgemont, South Dakota; Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butz, T.R.; Dean, N.E.; Bard, C.S.

1980-05-31

Results of the Edgemont detailed geochemical survey are reported. Field and laboratory data are presented for 109 groundwater and 419 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are given. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwaters containing greater than or equal to 7.35 ppB uranium are present in scattered clusters throughout the area sampled. Most of these groundwaters are from wells drilled where the Inyan Kara Group is exposed at themore » surface. The exceptions are a group of samples in the northwestern part of the area sampled and south of the Dewey Terrace. These groundwaters are also produced from the Inyan Kara Group where it is overlain by the Graneros Group and alluvium. The high uranium groundwaters along and to the south of the terrace are characterized by high molybdenum, uranium/specific conductance, and uranium/sulfate values. Many of the groundwaters sampled along the outcrop of the Inyan Kara Group are near uranium mines. Groundwaters have high amounts of uranium and molybdenum. Samples taken downdip are sulfide waters with low values of uranium and high values of arsenic, molybdenum, selenium, and vanadium. Stream sediments containing greater than or equal to 5.50 ppM soluble uranium are concentrated in basins draining the Graneros and Inyan Kara Groups. These values are associated with high values for arsenic, selenium, and vanadium in samples from both groups. Anomalous values for these elements in the Graneros Group may be caused by bentonite beds contained in the rock units. As shown on the geochemical distribution plot, high uranium values that are located in the Inyan Kara Group are almost exclusively draining open-pit uranium mines.« less

Isotopic composition and neutronics of the Okelobondo natural reactor

NASA Astrophysics Data System (ADS)

Palenik, Christopher Samuel

The Oklo-Okelobondo and Bangombe uranium deposits, in Gabon, Africa host Earth's only known natural nuclear fission reactors. These 2 billion year old reactors represent a unique opportunity to study used nuclear fuel over geologic periods of time. The reactors in these deposits have been studied as a means by which to constrain the source term of fission product concentrations produced during reactor operation. The source term depends on the neutronic parameters, which include reactor operation duration, neutron flux and the neutron energy spectrum. Reactor operation has been modeled using a point-source computer simulation (Oak Ridge Isotope Generation and Depletion, ORIGEN, code) for a light water reactor. Model results have been constrained using secondary ionization mass spectroscopy (SIMS) isotopic measurements of the fission products Nd and Te, as well as U in uraninite from samples collected in the Okelobondo reactor zone. Based upon the constraints on the operating conditions, the pre-reactor concentrations of Nd (150 ppm +/- 75 ppm) and Te (<1 ppm) in uraninite were estimated. Related to the burnup measured in Okelobondo samples (0.7 to 13.8 GWd/MTU), the final fission product inventories of Nd (90 to 1200 ppm) and Te (10 to 110 ppm) were calculated. By the same means, the ranges of all other fission products and actinides produced during reactor operation were calculated as a function of burnup. These results provide a source term against which the present elemental and decay abundances at the fission reactor can be compared. Furthermore, they provide new insights into the extent to which a "fossil" nuclear reactor can be characterized on the basis of its isotopic signatures. In addition, results from the study of two other natural systems related to the radionuclide and fission product transport are included. A detailed mineralogical characterization of the uranyl mineralogy at the Bangombe uranium deposit in Gabon, Africa was completed to improve geochemical models of the solubility-limiting phase. A study of the competing effects of radiation damage and annealing in a U-bearing crystal of zircon shows that low temperature annealing in actinide-bearing phases is significant in the annealing of radiation damage.

Successful remediation of four uranium calibration pits at Technical Area II, Sandia National Laboratories, Albuquerque, New Mexico, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conway, R.; Wade, M.; Tharp, T.

1994-12-31

The first remediation of an Environmental Restoration (ER) Project site at Sandia National Laboratories (SNL) was successfully conducted in May and June 1994 at Technical Area II. The removal action involved four Uranium Calibration Pits (UCPs) filled with radioactive or hazardous materials. The concrete culvert pits were used to test and calibrate borehole radiometric logging tools for uranium exploration. The removal action consisted of excavating and containerizing the pit contents and contaminated soil beneath the culverts, removing the four culverts, and backfilling the excavation. Each UCP removal had unique complexities. Sixty 208-L drums of solid radioactive waste and eight 208-Lmore » drums of liquid hazardous waste were generated during the VCM. Two of the concrete culverts will be disposed as radioactive waste and two as solid waste. Uranium-238 was detected in UCP-2 ore material at 746 pci/g, and at 59 pci/g in UCP-1 silica sand. UCP-4 was empty; sludge from UCP-3 contained 122 mg/L (ppm) chromium.« less

Determination of lead, uranium, thorium, and thallium in silicate glass standard materials by isotope dilution mass spectrometry

USGS Publications Warehouse

Barnes, I.L.; Garner, E.L.; Gramlich, J.W.; Moore, L.J.; Murphy, T.J.; Machlan, L.A.; Shields, W.R.; Tatsumoto, M.; Knight, R.J.

1973-01-01

A set of four standard glasses has been prepared which have been doped with 61 different elements at the 500-, 50-, 1-, and 0.02-ppm level. The concentrations of lead, uranium, thorium, and thallium have been determined by isotope dilution mass spectrometry at a number of points in each of the glasses. The results obtained from independent determinations in two laboratories demonstrate the homogeneity of the samples and that precision of the order of 0.5% (95% L.E.) may be obtained by the method even at the 20-ppb level for these elements. The chemical and mass spectrometric procedures necessary are presented.

Biogeochemical study of termite mounds: a case study from Tummalapalle area of Andhra Pradesh, India.

PubMed

Arveti, Nagaraju; Reginald, S; Kumar, K Sunil; Harinath, V; Sreedhar, Y

2012-04-01

Termite mounds are abundant components of Tummalapalle area of uranium mineralization of Cuddapah District of Andhra Pradesh, India. The systematic research has been carried out on the application of termite mound sampling to mineral exploration in this region. The distribution of chemical elements Cu, Pb, Zn, Ni, Co, Cr, Li, Rb, Sr, Ba, and U were studied both in termite soils and adjacent surface soils. Uranium accumulations were noticed in seven termite mounds ranging from 10 to 36 ppm. A biogeochemical parameter called "Biological Absorption Coefficient" of the termite mounds indicated the termite affected soils contained huge amounts of chemical elements than the adjacent soils.

Optical and laser spectroscopic diagnostics for energy applications

NASA Astrophysics Data System (ADS)

Tripathi, Markandey Mani

The continuing need for greater energy security and energy independence has motivated researchers to develop new energy technologies for better energy resource management and efficient energy usage. The focus of this dissertation is the development of optical (spectroscopic) sensing methodologies for various fuels, and energy applications. A fiber-optic NIR sensing methodology was developed for predicting water content in bio-oil. The feasibility of using the designed near infrared (NIR) system for estimating water content in bio-oil was tested by applying multivariate analysis to NIR spectral data. The calibration results demonstrated that the spectral information can successfully predict the bio-oil water content (from 16% to 36%). The effect of ultraviolet (UV) light on the chemical stability of bio-oil was studied by employing laser-induced fluorescence (LIF) spectroscopy. To simulate the UV light exposure, a laser in the UV region (325 nm) was employed for bio-oil excitation. The LIF, as a signature of chemical change, was recorded from bio-oil. From this study, it was concluded that phenols present in the bio-oil show chemical instability, when exposed to UV light. A laser-induced breakdown spectroscopy (LIBS)-based optical sensor was designed, developed, and tested for detection of four important trace impurities in rocket fuel (hydrogen). The sensor can simultaneously measure the concentrations of nitrogen, argon, oxygen, and helium in hydrogen from storage tanks and supply lines. The sensor had estimated lower detection limits of 80 ppm for nitrogen, 97 ppm for argon, 10 ppm for oxygen, and 25 ppm for helium. A chemiluminescence-based spectroscopic diagnostics were performed to measure equivalence ratios in methane-air premixed flames. A partial least-squares regression (PLS-R)-based multivariate sensing methodology was investigated. It was found that the equivalence ratios predicted with the PLS-R-based multivariate calibration model matched with the experimentally measured equivalence ratios within 7 %. A comparative study was performed for equivalence ratios measurement in atmospheric premixed methane-air flames with ungated LIBS and chemiluminescence spectroscopy. It was reported that LIBS-based calibration, which carries spectroscopic information from a "point-like-volume," provides better predictions of equivalence ratios compared to chemiluminescence-based calibration, which is essentially a "line-of-sight" measurement.

Pilot Study to Evaluate Hydrogen Injection for Stimulating Reduction and Immobilization of Uranium in Groundwater at an ISR Mining Site

NASA Astrophysics Data System (ADS)

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

2011-12-01

State and federal regulations require that groundwater at in-situ recovery (ISR) uranium mining operations be restored to pre-mining conditions. Reverse osmosis (RO) filtration of several pore volumes of the post-leached groundwater and reinjection of the clean permeate is the most common technology currently used for restoring groundwater at uranium ISR sites. However, this approach does not revert the formation back to its initial reducing conditions, which can potentially impede timely groundwater restoration. In-situ biostimulation of indigenous iron- and sulfate reducing bacteria by injection of organic electron donors (e.g., ethanol, acetate, and lactate) to promote soluble uranium reduction and immobilization has been the subject of previous studies. However, injection of organic substrates has been observed to cause aquifer clogging near the injection point. In addition, U(VI) solubility may be enhanced through complexation with carbonate generated by organic carbon oxidation. An alternative approach that may overcome these problems involves the use of hydrogen as a reductant to promote microbial reduction and immobilization of U(VI) in situ. To test this approach, approximately 100,000 scf of compressed hydrogen gas was injected into a leached unconsolidated sand zone over two months at an ISR mining site. During this time groundwater was recirculated between injection and extraction wells (separated by 130 ft) at a rate of about 40 gpm and bromide was coinjected as a conservative tracer. A well monitoring program has been executed since June 2009 to evaluate the performance of the hydrogen injection. Current results show that U(VI) has been reduced from 4.2 to 0.05 ppm in the area surrounding the injection well and to 2.0 ± 0.3 ppm in the area surrounding the extraction well and two intermediate monitoring wells. Other water quality changes near the injection well include significant decreases in concentrations of Mo, sulfate, Fe, Mn, bicarbonate, Ca, and Eh, and increases in pH, methane, and sulfide. No significant rebound of soluble uranium concentrations was observed, but significant rebounds in molybdenum and sulfate have been observed. Ongoing studies are evaluating the effective zone of influence of the hydrogen injection.

76 FR 63330 - Policy Regarding Submittal of Amendments for Processing of Equivalent Feed at Licensed Uranium...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-12

... NUCLEAR REGULATORY COMMISSION [NRC-2011-0217] Policy Regarding Submittal of Amendments for... NRC's policy regarding receipt and processing, without a license amendment, of equivalent feed at an... and Management System (ADAMS) and in the NRC Library, and update the date voluntary responses should...

Reconnaissance for radioactive materials in the southern part of Brazil

USGS Publications Warehouse

Pierson, Charles T.; Haynes, Donald D.; Filho, Evaristo Ribeiro

1957-01-01

During 1954-1956 a reconnaissance for radioactive minerals was made with carborne, airborne and handborne scintillation equipment in the southern Brazilian states of Rio de Janeiro, Sao Paulo, Parana, Santa Catarina and Rio Grande do Sul. During the traverse covering more than 5,000 kilometers the authors checked the radioactivity of Precambrian igneous and metamorphic rocks, Paleozoic, Mesozoic and Cenozoic sedimentary rocks, and Mesozoic alkalic intrusive and basaltic extrusive rocks. The 22 samples collected contained from 0.003 to 0.029 percent equivalent uranium oxide and from 0.10 to 0.91 percent equivalent thorimn; two samples were taken from radioactive pegmati tes for mineralogic studies. None of the localities is at present a commercial source of uranium or thorium; however, additional work should be done near the alkalic stock at Lages in the State of Santa Catarina and at the Passo das Tropas fossil plant locality near Santa Maria in the state of Rio Grande do Sul. Near Lages highly altered alkalic rock from a dike contained 0.026 percent uranium oxide. At Passo das Tropas highly altered, limonite-impregnated sandstone from the Rio do Rasto group of sedimentary rocks contained 0.029 percent uranium oxide.

Investigation of distribution of radioactivity with effects of heavy metals in toothpastes from Penang markets.

PubMed

Salih, Najeba F; Jafri, Zubir M; Jaafar, Mohamad S

2016-12-01

This study was carried out to determine the concentration of 222 Rn, 226 Ra, and 238 U in 25 different toothpastes available in the local market in Penang, Malaysia, using a CR-39 detector. The results showed the maximum concentration of radon/ radium/uranium to be 4197.644 Bq.m -3 , 54.369 Bq.Kgm -1 , and 0.044 ppm in Colgate4; the annual effective dose was found (0.402 mSvy -1 ) in S07. The average concentration of radon (42 %, 3.224 KBq.m -3 ) was higher than the concentration of 214 Po, 218 Po in POS (32 %, 2.415 KBq.m -3 ) and POW (26 %, 1.979 KBq.m -3 ). Also the values of pH of samples ranged from 4.21 (highly acidic) in S04 to 9.97 (highly basic) in S07, with an average of 6.33 which tended towards an acidic behavior; a low or high pH for a long period of time can cause harmful side-effects and enamel erosion. Concentrations of heavy metals varied from the maximum value 56.156 ppm in the Ca elements in the Colgate 4 sample to a minimum value of -0.858 ppm in the Cd elements in Colgate 6 (Ca 56.156 ppm > Cd 51.572 ppm > Zn 41.039 ppm > Mg 11.682 ppm > Pb 11.009 ppm]. Monitoring the accumulation of these metals in toothpaste samples is very important: the average annual effective dose (0.3118 mSvy -1 ) was below the range (3-10 mSvy -1 ) reported by ICRP (1993), and therefore there is no evidence of health problems. Significant strong positive correlations were found (r = 1, Pearson correlation, p < 0.000) in concentration of radon, radium, uranium, annual effective dose, pH, and electrical conductivity.

Novel poly(imide dioxime) sorbents: Development and testing for enhanced extraction of uranium from natural seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sadananda; Brown, Suree; Mayes, Richard T.

2016-04-09

We synthesized a new series of amidoxime-based polymer adsorbents at the Oak Ridge National Laboratory (ORNL) by electron beam induced grafting of acrylonitrile and itaconic acid onto polyethylene fiber. We also demonstrate hydroxylamine derivatives of poly(acrylonitrile) (PAN) moiety to possess two kinds of functional groups: open-chain amidoxime and cyclic imide dioxime. The open-chain amidoxime is shown to convert to imide dioxime on heat treatment in the presence of an aprotic solvent, like dimethylsulfoxide (DMSO). Furthermore, the formation of amidoxime and imide dioxime was confirmed by 13C CP-MAS spectra. The adsorbents were evaluated for uranium adsorption efficiency at ORNL with simulatedmore » seawater spiked with 8 ppm uranium and 5 gallon seawater in a batch reactor, and in flow-through columns with natural seawater at the Marine Science Laboratory (MSL) of Pacific Northwest National Laboratory (PNNL) at Sequim Bay, WA. The DMSO-heat-treated sorbents adsorbed uranium as high as 4.48 g-U/kg-ads. from seawater. Experimental evidence is presented that the poly(imide dioxime) is primarily responsible for enhanced uranium adsorption capacity from natural seawater. The conjugated system in the imide dioxime ligand possesses increased electron donation ability, which is believed to significantly enhance the uranyl coordination in seawater.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE PAGES

Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

2016-08-31

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Jones, Nina; Spano, Tyler

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Pigment identification, antioxidant activity, and nutrient composition of Tinospora cordifolia (willd.) Miers ex Hook. f & Thoms fruit.

PubMed

Khan, Mohammad Imtiyaj; Harsha, P S C Sri; Giridhar, P; Ravishankar, G A

2011-05-01

The stem, leaf, and root of Tinospora cordifolia (willd.) have been highly exploited for medicinal preparations; however, the nutritional and nutraceutical potential of its attractive red berries (fruits) have not so far been studied. Pigments, berberine (107.0 mg/100 g) and lycopene (50.8 mg/100 g), were identified in the deseeded fruit. Total phenol content in the fruit was 3.2 mg gallic acid equivalent/g. The IC(50) of DPPH· (82, and 468 ppm) and OH· (100, and 1,000 ppm) scavenging activity, and the EC(50) of reducing power (2,616, and 1,472 ppm) of hexane and methanol extracts, respectively, were observed. Oxygen radical absorbance capacities of the fruit extracts (150 and 300 ppm) were 1,107 and 2,614 μM trolox equivalent/g, respectively. Nutrient composition including carbohydrate (18.4%), proteins (1.5%), lipids (6%) of which ∼62% was unsaturated fatty acids, vitamins like ascorbic acid (0.24 μg), niacin (0.7 mg), and tocopherols (2.4 mg) in 100 g fruits were determined. Potassium content was 1.2 g/100 g dry tissue of berries. These findings show that components of T. cordifolia fruit could be bioactive and used in food, pharmaceutical, and cosmetics.

Determination of low ppm levels of dimethyl sulfate in an aqueous soluble API intermediate using liquid-liquid extraction and GC-MS.

PubMed

Zheng, Jie; Pritts, Wayne A; Zhang, Shuhong; Wittenberger, Steve

2009-12-05

Dimethyl sulfate (DMS) is an alkylating reagent commonly used in organic syntheses and pharmaceutical manufacturing processes. Due to its potential carcinogenicity, the level of DMS in the API process needs to be carefully monitored. However, in-process testing for DMS is challenging because of its reactivity and polarity as well as complex matrix effects. In this short communication, we report a GC-MS method for determination of DMS in an API intermediate that is a methyl sulfate salt. To overcome the complex matrix interference, DMS and an internal standard, d6-DMS, were extracted from the matrix with methyl tert-butyl ether. GC separation was conducted on a DB-624 column (30 m long, 0.32 mm ID, 1.8 microm film thickness). MS detection was performed on a single-quad Agilent MSD equipped with an electron impact source while the MSD signal was acquired in selected ion monitoring mode. This GC/MS method showed a linear response for DMS equivalent from 1.0 to 60 ppm. The practical quantitation limit for DMS was 1.0 ppm and the practical detection limit was 0.3 ppm. The relative standard derivation for analyte response was found as 0.1% for six injections of a working standard equivalent to 18.6 ppm of DMS. The spike recovery was ranged from 102.1 to 108.5% for a sample of API intermediate spiked with 8.0 ppm of DMS. In summary, the GC/MS method showed adequate specificity, linearity, sensitivity, repeatability and accuracy for determination of DMS in the API intermediate. This method has been successfully applied to study the efficiency of removing DMS from the process.

Preliminary study of uranium favorability of the Boulder batholith, Montana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castor, S.B.; Robins, J.W.

1978-01-01

The Boulder batholith of southwestern Montana is a composite Late Cretaceous intrusive mass, mostly composed of quartz monzonite and granodiorite. This study was not restricted to the plutonic rocks; it also includes younger rocks that overlie the batholith, and older rocks that it intrudes. The Boulder batholith area has good overall potential for economic uranium deposits, because its geology is similar to that of areas that contain economic deposits elsewhere in the world, and because at least 35 uranium occurrences of several different types are present. Potential is greatest for the occurrence of small uranium deposits in chalcedony veins andmore » base-metal sulfide veins. Three areas may be favorable for large, low-grade deposits consisting of a number of closely spaced chalcedony veins and enriched wall rock; the Mooney claims, the Boulder area, and the Clancy area. In addition, there is a good possibility of by-product uranium production from phosphatic black shales in the project area. The potential for uranium deposits in breccia masses that cut prebatholith rocks, in manganese-quartz veins near Butte, and in a shear zone that cuts Tertiary rhyolite near Helena cannot be determined on the basis of available information. Low-grade, disseminated, primary uranium concentrations similar to porphyry deposits proposed by Armstrong (1974) may exist in the Boulder batholith, but the primary uranium content of most batholith rocks is low. The geologic environment adjacent to the Boulder batholith is similar in places to that at the Midnite mine in Washington. Some igneous rocks in the project area contain more than 10 ppM U/sub 3/O/sub 8/, and some metasedimentary rocks near the batholith contain reductants such as sulfides and carbonaceous material.« less

Uranium in Holocene valley-fill sediments, and uranium, radon, and helium in waters, Lake Tahoe-Carson Range area, Nevada and California, U.S.A.

USGS Publications Warehouse

Otton, J.K.; Zielinski, R.A.; Been, J.M.

1989-01-01

Uraniferous Holocene sediments occur in the Carson Range of Nevada and California, U.S.A., between Lake Tahoe and Carson Valley. The hosts for the uranium include peat and interbedded organic-rich sand, silt, and mud that underly valley floors, fens, and marshes along stream valleys between the crest of the range and the edge of Lake Tahoe. The known uranium accumulations extend along the Carson Range from the area just southeast of South Lake Tahoe northward to the area just east of Carson City; however, they almost certainly continue beyond the study area to the north, west, and south. Due to the young age of the accumulations, uranium in them is in gross disequilibrium with its highly radioactive daughter products. These accumulations have thus escaped discovery with radiation detection equipment in the past. The uranium content of these sediments approaches 0.6 percent; however, the average is in the range of 300-500 ppm. Waters associated with these sediments locally contain as much as 177 ppb uranium. Modest levels of helium and radon also occur in these waters. Uraniferous waters are clearly entering the private and public water supply systems in some parts of the study area; however, it is not known how much uranium is reaching users of these water supplies. Many of the waters sampled in the study area exceed the published health effects guidance level of the Environmental Protection Agency. Regulatory standards for uranium in waters have not been published, however. Much uranium is stored in the sediments along these stream valleys. Estimates for a marsh and a fen along one drainage are 24,000 and 15,000 kg, respectively. The potential effects of man-induced environmental changes on the uranium are uncertain. Laboratory studies of uraniferous sediment rich in organic matter may allow us to evaluate the potential of liberating uranium from such sediments and creating transient increases in the level of uranium moving in water in the natural environment. ?? 1989 Springer-Verlag New York Inc.

Diode laser absorption measurement and analysis of HCN in atmospheric-pressure, fuel-rich premixed methane/air flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gersen, S.; Mokhov, A.V.; Levinsky, H.B.

Measurements of HCN in flat, fuel-rich premixed methane/air flames at atmospheric pressure are reported. Quartz-microprobe sampling followed by wavelength modulation absorption spectroscopy with second harmonic detection was used to obtain an overall measurement uncertainty of better than 20% for mole fractions HCN on the order of 10 ppm. The equivalence ratio, {phi}, was varied between 1.3 and 1.5, while the flame temperature was varied independently by changing the mass flux through the burner surface at constant equivalence ratio. Under the conditions of the experiments, the peak mole fractions vary little, in the range of 10-15 ppm. Increasing the flame temperaturemore » by increasing the mass flux had little influence on the peak mole fraction, but accelerated HCN burnout substantially. At high equivalence ratio and low flame temperature, HCN burnout is very slow: at {phi}=1.5, {proportional_to}10ppm HCN is still present 7 mm above the burner surface. Substantial quantitative disagreement is observed between the experimental profiles and those obtained from calculations using GRI-Mech 3.0, with the calculations generally overpredicting the results significantly. Changing the rates of key formation and consumption reactions for HCN can improve the agreement, but only by making unreasonable changes in these rates. Inclusion of reactions describing NCN formation and consumption in the calculations improves the agreement with the measurements considerably. (author)« less

Argon/UF6 plasma exhaust gas reconstitution experiments using preheated fluorine and on-line diagnostics. [fissioning uranium plasma core reactor design

NASA Technical Reports Server (NTRS)

Roman, W. C.

1979-01-01

The feasibility of employing a flowing, high-temperature, pure fluorine/UF6 regeneration system to efficiently convert a large fraction of the effluent plasma exhaust back to pure UF6 was demonstrated. The custom built T.O.F. mass spectrometer sampling system permitted on-line measurements of the UF6 concentration at different locations in the exhaust system. Negligible amounts ( 100 ppm) of UF6 were detected in the axial bypass exhaust duct and the exhaust ducts downstream of the cryogenic trap system used to collect the UF6, thus verifying the overall system efficiency over a range of operating conditions. Use of a porous Monel duct as part of the exhaust duct system, including provision for injection of pure fluorine, provided a viable technique to eliminate uranium compound residue on the inside surface of the exhaust ducts. Typical uranium compound mass deposition per unit area of duct was 2 micron g/sq cm. This porous duct technique is directly applicable to future uranium compound transfer exhaust systems. Throughout these experiments, additional basic data on the corrosion aspects of hot, pressurized UF6/fluorine were also accumulated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sadananda; Brown, Suree S.; Mayes, Richard T.

A new series of amidoxime-based polymer adsorbents were synthesized at the Oak Ridge National Laboratory (ORNL) by electron beam induced grafting of acrylonitrile and itaconic acid onto polyethylene fiber. Hydroxylamine derivatives of poly(acrylonitrile) (PAN) moiety are demonstrated to possess two kinds of functional groups: open-chain amidoxime and cyclic imide dioxime. The open-chain amidoxime is shown to convert to imide dioxime on heat treatment in the presence of an aprotic solvent, like dimethylsulfoxide (DMSO). The formation of amidoxime and imide dioxime was confirmed by 13-C CPMAS spectra. The adsorbents were evaluated for uranium adsorption efficiency at ORNL with simulated seawater spikedmore » with 8 ppm uranium and 5 gallon seawater in a batch reactor, and in flow-through columns with natural seawater at the Marine Science Laboratory (MSL) of Pacific Northwest National Laboratory (PNNL) at Sequim Bay, WA. The DMSO-heat-treated sorbents adsorbed uranium as high as 4.48 g-U/kg-ads. from seawater. Experimental evidence is presented that the poly(imide dioxime) is primarily responsible for enhanced uranium adsorption capacity from natural seawater. The conjugated system in the imide dioxime ligand possesses increased electron donation ability, which is believed to significantly enhance the uranyl coordination in seawater« less

The in-plant evaluation of a uranium NDA system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprinkle, J.K. Jr.; Baxman, H.R.; Langner, D.G.

1979-12-31

The Los Alamos Scientific Laboratory has an unirradiated enriched uranium reprocessing facility. Various types of solutions are generated in this facility, including distillates and raffinates containing ppm of uranium and concentrated solutions with up to 400 grams U/t. In addition to uranyl nitrate and HNO{sub 3}, the solutions may also contain zirconium, niobium, fluoride, and small amounts of many metals. A uranium solution assay system (USAS) has been installed to allow accurate and more timely process control, accountability, and criticality data to be obtained. The USAS assays are made by a variety of techniques that depend upon state-of-the-art high-resolution Ge(Li)more » gamma-ray spectroscopy integrated with an interactive, user-oriented computer software package. Tight control of the system`s performance is maintained by constantly monitoring the USAS status. Daily measurement control sequences are required, and the user is forced by the software to perform these sequences. Routine assays require 400 or 1000 seconds for a precision of 0.5% over the concentration range of 5--400 g/t. A comparison of the USAS precision and accuracy with that obtained by traditional destructive analytical chemistry techniques (colorimetric and volumetric) is presented.« less

The in-plant evaluation of a uranium NDA system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprinkle, J.K. Jr.; Baxman, H.R.; Langner, D.G.

1979-01-01

The Los Alamos Scientific Laboratory has an unirradiated enriched uranium reprocessing facility. Various types of solutions are generated in this facility, including distillates and raffinates containing ppm of uranium and concentrated solutions with up to 400 grams U/t. In addition to uranyl nitrate and HNO{sub 3}, the solutions may also contain zirconium, niobium, fluoride, and small amounts of many metals. A uranium solution assay system (USAS) has been installed to allow accurate and more timely process control, accountability, and criticality data to be obtained. The USAS assays are made by a variety of techniques that depend upon state-of-the-art high-resolution Ge(Li)more » gamma-ray spectroscopy integrated with an interactive, user-oriented computer software package. Tight control of the system's performance is maintained by constantly monitoring the USAS status. Daily measurement control sequences are required, and the user is forced by the software to perform these sequences. Routine assays require 400 or 1000 seconds for a precision of 0.5% over the concentration range of 5--400 g/t. A comparison of the USAS precision and accuracy with that obtained by traditional destructive analytical chemistry techniques (colorimetric and volumetric) is presented.« less

Bioaccumulation of metals by lichens: Uptake of aqueous uranium by Peltigera membranacea as a function of time and pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haas, J.R.; Bailey, E.H.; Purvis, O.W.

1998-11-01

Uranium sorption experiments were carried out at {approximately}25 C using natural samples of the lichen Peltigera membranacea. Thalli were incubated in solutions containing 100 ppm U for up to 24 h at pH values from 2 to 10. Equilibrium sorption was not observed at less than {approximately}6 h under any pH condition. U sorption was strongest in the pH range 4--5, with maximum sorption occurring at a pH of 4.5 and an incubation time of 24 h. Maximum U uptake by P. membranacea averaged {approximately}42,000 ppm, or {approximately}4.2 wt% U. This appears to represent the highest concentration of biosorbed U,more » relative to solution U activity, of any lichen reported to date. Investigation of post-experimental lichen tissues using electron probe microanalysis (EPM) reveals that U uptake is spatially heterogeneous within the lichen body, and that U attains very high local concentrations on scattered areas of the upper cortex. Energy dispersive spectroscopic (EDS) analysis reveals that strong U uptake correlates with P signal intensity, suggesting involvement of biomass-derived phosphate ligands or surface functional groups in the uptake process.« less

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour.

PubMed

Martin, T L; Coe, C; Bagot, P A J; Morrall, P; Smith, G D W; Scott, T; Moody, M P

2016-07-12

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

NASA Astrophysics Data System (ADS)

Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W.; Scott, T.; Moody, M. P.

2016-07-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

PubMed Central

Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W; Scott, T.; Moody, M. P.

2016-01-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour. PMID:27403638

Selected annotated bibliography of the geology and occurrence of uranium-bearing marine black shales in the United States

USGS Publications Warehouse

Fix, Carolyn E.

1956-01-01

The bibliography consists of annotations or abstracts of selected reports that pertain to the geology and occurrence of uranium in marine black shales and their metamorphic equivalents in the United States. Only those reports that were available to the public prior to June 30, 1956, are included. Most of the reports may be consulted in the larger public, university, or scientific libraries. A few reports that have been released to the public in open file may be consulted at designated offices of the Geological Survey. An effort has been made to include only those references to shales whose uranium is believed to be of syngenetic origin and whose major source of radioactivity is uranium. Many general papers on the geology of uranium deposits refer to marine black shales, and some of these general papers have been included.

Implications of modelled radioactivity measurements along coastal Odisha, Eastern India for heavy mineral resources

NASA Astrophysics Data System (ADS)

Ghosal, S.; Agrahari, S.; Guin, R.; Sengupta, D.

2017-01-01

A radioelemental assemblage assessment of two beaches of Odisha is performed for the first time. The radiation is measured in two ways, both on field with the help of a hand held environmental survey meter and in the laboratory, where the concentrations of radionuclide's 238U, 232Th and 4K have been determined with the help of High Purity Germanium detector (HPGe). Mineralogical analysis of selected samples has been performed with the help of X-Ray Fluorescence Spectrometry (XRF). A marked difference between the concentration of Uranium (274 Bq kg-1) and Thorium (2489 Bq kg-1) is observed and discussed based on the geology of the area. The placer deposits showing an enrichment of thorium can be an important source of nuclear fuel for the thorium based nuclear reactors. The ratio of thorium and uranium concentrations gives us an idea about the coastal processes associated with the beach. Statistical analysis of the data shows a positive correlation between 238U and 232Th and a strong negative correlation is indicated between 4 K and 238U, 232Th. A cross plot between the equivalent thorium and the equivalent uranium and the equivalent thorium and potassium, represents the nature of deposition and its association with the heavy mineral along with the radioactive elements. Heavy minerals exhibit an increasing trend towards Northeast-Southwest along the south eastern coast of India.

Adsorbent Alkali Conditioning for Uranium Adsorption from Seawater. Adsorbent Performance and Technology Cost Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsouris, Costas; Mayes, Richard T.; Janke, Christopher James

The Fuel Resources program of the Fuel Cycle Research and Development program of the Office of Nuclear Energy (NE) is focused on identifying and implementing actions to assure that nuclear fuel resources are available in the United States. An immense source of uranium is seawater, which contains an estimated amount of 4.5 billion tonnes of dissolved uranium. This unconventional resource can provide a price cap and ensure centuries of uranium supply for future nuclear energy production. NE initiated a multidisciplinary program with participants from national laboratories, universities, and research institutes to enable technical breakthroughs related to uranium recovery from seawater.more » The goal is to develop advanced adsorbents to reduce the seawater uranium recovery technology cost and uncertainties. Under this program, Oak Ridge National Laboratory (ORNL) has developed a new amidoxime-based adsorbent of high surface area, which tripled the uranium capacity of leading Japanese adsorbents. Parallel efforts have been focused on the optimization of the physicochemical and operating parameters used during the preparation of the adsorbent for deployment. A set of parameters that need to be optimized are related to the conditioning of the adsorbent with alkali solution, which is necessary prior to adsorbent deployment. Previous work indicated that alkali-conditioning parameters significantly affect the adsorbent performance. Initiated in 2014, this study had as a goal to determine optimal parameters such as base type and concentration, temperature, and duration of conditioning that maximize the uranium adsorption performance of amidoxime functionalized adsorbent, while keeping the cost of uranium production low. After base-treatment at various conditions, samples of adsorbent developed at ORNL were tested in this study with batch simulated seawater solution of 8-ppm uranium concentration, batch seawater spiked with uranium nitrate at 75-100 ppb uranium, and continuous-flow natural seawater at the Pacific Northwest National Laboratory (PNNL). Fourier Transform Infrared (FTIR) spectroscopy, Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), and elemental analysis were used to characterize the adsorbent at different stages of adsorbent preparation and treatment. The study can be divided into two parts: (A) investigation of optimal parameters for KOH adsorbent conditioning and (B) investigation of other possible agents for alkali conditioning, including cost analysis on the basis of uranium production. In the first part of the study, tests with simulated seawater containing 8 ppm uranium showed that the uranium adsorption capacity increased with an increase in the KOH concentration and conditioning time and temperature at each of the KOH concentrations used. FTIR and solid state NMR studies indicated that KOH conditioning converts the amidoxime functional groups into more hydrophilic carboxylate. The longer the KOH conditioning time, up to three hours, the higher was the loading capacity from the simulated seawater solution which is composed of only uranyl, sodium, chloride, and carbonate ions. Marine testing with natural seawater, on the other hand, showed that the uranium adsorption capacity of the adsorbent increased with KOH conditioning temperature, and gradually decreased with increasing KOH conditioning time from one hour to three hours at 80 C. This behavior is due to the conversion of amidoxime to carboxylate. The carboxylate groups are needed to increase the hydrophilicity of the adsorbent; however, conversion of a significant amount of amidoxime to carboxylate leads to loss in selectivity toward uranyl ions. Thus, there is an optimum KOH conditioning time for each temperature at which an optimum ratio between amidoxime and carboxylate is reached. For the case of base conditioning with 0.44 M KOH at 80 C, the optimal conditioning time is 1 hour, with respect to the highest uranium loading capacity from natural seawater. Uptake of other metal ions such as V, Fe, and Cu follows the same trend as that of uranium. Also, the uptake of Ca, Mg, and Zn ions increased with increasing KOH conditioning time, probably due to formation of more carboxylates, which leads to conversion of uranium-selective binding sites to less selective sites. In the second part of the study, inorganic based reagents such as sodium hydroxide (NaOH), sodium carbonate (Na 2CO 3), cesium hydroxide (CsOH), as well as organic based reagents such as ammonium hydroxide (AOH), tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), triethylmethylammonium hydroxide (TEMAOH), tetrapropylammonium hydroxide (TPAOH) and tetrabutylammonium hydroxide (TBAOH), in addition to KOH, were used for alkaline conditioning. NaOH has emerged as a better reagent for alkaline conditioning of amidoxime-based adsorbent because of higher uranium uptake capacity, higher uranium uptake selectivity ...« less

10 CFR Appendix A to Part 40 - Criteria Relating to the Operation of Uranium Mills and the Disposition of Tailings or Wastes...

Code of Federal Regulations, 2012 CFR

2012-01-01

... itself. (6) The design requirements in this criterion for longevity and control of radon releases apply... radiological and nonradiological hazards associated with the sites, which is equivalent to, to the extent... “reasonably achievable” as equivalent terms. Decisions involved these terms will take into account the state...

10 CFR Appendix A to Part 40 - Criteria Relating to the Operation of Uranium Mills and the Disposition of Tailings or Wastes...

Code of Federal Regulations, 2014 CFR

2014-01-01

... associated with the sites, which is equivalent to, to the extent practicable, or more stringent than the... this appendix, the Commission will consider “practicable” and “reasonably achievable” as equivalent... formation, group of formations, or part of a formation capable of yielding a significant amount of ground...

TH-AB-209-02: Gadolinium Measurements in Human Bone Using in Vivo K X-Ray Fluorescence (KXRF) Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mostafaei, F; Nie, L

Purpose: Improvement in an in vivo K x-ray fluorescence system, based on 109Cd source, for the detection of gadolinium (Gd) in bone has been investigated. Series of improvements to the method is described. Gd is of interest because of the extensive use of Gd-based contrast agents in MR imaging and the potential toxicity of Gd exposure. Methods: A set of seven bone equivalent phantoms with different amount of Gd concentrations (from 0–100 ppm) has been developed. Soft tissue equivalent plastic plates were used to simulate the soft tissue overlaying the tibia bone in an in vivo measurement. A new 5more » GBq 109Cd source was used to improve the source activity in comparison to the previous study (0.17 GBq). An improved spectral fitting program was utilized for data analysis. Results: The previous published minimum detection limit (MDL) for Gd doped phantom measurements using KXRF system was 3.3 ppm. In this study the MDL for bare bone phantoms was found to be 0.8 ppm. Our previous study used only three layers of plastic (0.32, 0.64 and 0.96 mm) as soft tissue equivalent materials and obtained the MDL of 4–4.8 ppm. In this study the plastic plates with more realistic thicknesses to simulate the soft tissue covering tibia bone (nine thicknesses ranging from 0.61–6.13 mm) were used. The MDLs for phantoms were determined to be 1.8–3.5 ppm. Conclusion: With the improvements made to the technology (stronger source, improved data analysis algorithm, realistic soft tissue thicknesses), the MDL of the KXRF system to measure Gd in bare bone was improved by a factor of 4.1. The MDL is at the level of the bone Gd concentration reported in literature. Hence, the system is ready to be tested on human subjects to investigate the use of bone Gd as a biomarker for Gd toxicity.« less

K-Rb Laser Pump Lamp

DTIC Science & Technology

1975-11-01

for K-Rb Lamps With Xenon and Argon Figure 25 Specimen for Protective Coating Evaluation 65 Figure 26 Specimen Coated With Fused Tin- Aluminide After...through hot titanium and copper purifiers to maia.in low levels (a few ppm) of oxygen, nitrogen and water vapor. The box also contains an integral...case with titanium , zirconium, thorium, and other common reactive metals. 15 - -’-- .--󈨑CP>4 -_ A thin strip of uranium is inserted into the fill

Centrifugal Contactor Efficiency Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce Jay; Tillotson, Richard Dean; Grimes, Travis Shane

2017-01-01

The contactor efficiency of a 2-cm acrylic centrifugal contactor, fabricated by ANL using 3D printer technology was measured by comparing a contactor test run to 5-min batch contacts. The aqueous phase was ~ 3 ppm depleted uranium in 3 M HNO3, and the organic phase was 1 M DAAP/dodecane. Sampling during the contactor run showed that equilibrium was achieved within < 3 minutes. The contactor efficiency at equilibrium was 95% to 100 %, depending on flowrate.

40 CFR 86.1214-85 - Analytical gases.

Code of Federal Regulations, 2012 CFR

2012-07-01

... hydrogen with the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon... air” includes artificial “air” consisting of a blend of nitrogen and oxygen with oxygen concentrations...

40 CFR 86.1214-85 - Analytical gases.

Code of Federal Regulations, 2013 CFR

2013-07-01

... hydrogen with the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon... air” includes artificial “air” consisting of a blend of nitrogen and oxygen with oxygen concentrations...

40 CFR 86.1214-85 - Analytical gases.

Code of Federal Regulations, 2010 CFR

2010-07-01

... hydrogen with the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon... air” includes artificial “air” consisting of a blend of nitrogen and oxygen with oxygen concentrations...

40 CFR 86.1214-85 - Analytical gases.

Code of Federal Regulations, 2011 CFR

2011-07-01

... hydrogen with the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon... air” includes artificial “air” consisting of a blend of nitrogen and oxygen with oxygen concentrations...

NTP Toxicology and Carcinogenesis Studies of EMODIN (CAS NO. 518-82-1) Feed Studies in F344/N Rats and B6C3F1 Mice.

PubMed

2001-06-01

Emodin is a naturally occurring anthraquinone present in the roots and bark of numerous plants of the genus Rhamnus. Extracts from the roots, bark, and/or dried leaves of buckthorn, senna, cascara, aloe, frangula, and rhubarb have been used as laxatives since ancient times and currently are widely used in the preparation of herbal laxative preparations. Anthraquinone glycosides are poorly absorbed from the gastrointestinal tract but are cleaved by gut bacteria to produce aglycones (such as emodin) that are more readily absorbed and are responsible for the purgative properties of these preparations. There is extensive exposure to emodin and other anthraquinones resulting from the use of herb-based stimulant laxatives. Reports that 1,8-dihydroxyanthraquinone, a commonly used laxative ingredient, caused tumors in the gastrointestinal tract of rats raised the possibility of an association between colorectal cancer and the use of laxatives containing anthraquinones. Because emodin is a hydroxyanthraquinone structurally similar to 1,8-dihydroxyanthraquinone, is present in herbal laxatives, and was reported to be mutagenic in bacteria, it was considered a potential carcinogen and was selected for in-depth evaluation. Male and female F344/N rats and B6C3F1 mice were exposed to emodin (at least 94% pure) in feed for 16 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, rat and mouse bone marrow cells, and mouse peripheral blood erythrocytes. 16-DAY STUDY IN RATS: Groups of five male and five female rats were fed diets containing 0, 600, 2,000, 5,500, 17,000, or 50,000 ppm emodin (equivalent to average daily doses of approximately 50, 170, 480, 1,400, or 3,700 mg emodin/kg body weight to males and 50, 160, 460, 1,250, or 2,000 mg/kg to females) for 15 (males) or 16 (females) days. Three female rats died before the end of the study. Mean body weights of males and females exposed to 5,500 ppm or greater were significantly less than those of the controls. Feed consumption by males and females receiving 17,000 or 50,000 ppm was decreased throughout the study. Macroscopic lesions were present in the kidney of rats exposed to 17,000 or 50,000 ppm. 16-DAY STUDY IN MICE: Groups of five male and five female mice were fed diets containing 0, 600, 2,000, 5,500, 17,000, or 50,000 ppm emodin (equivalent to average daily doses of approximately 120, 400, 1,200, or 3,800 mg/kg to males and 140, 530, 1,600, or 5,000 mg/kg to females; 50,000 ppm equivalents were not calculated due to high mortality) for 15 (males) or 16 (females) days. All mice exposed to 50,000 ppm died before the end of the study. Mice in the 17,000 ppm groups lost weight during the study. Feed consumption by 5,500 ppm females was greater than that by the controls throughout the study. Macroscopic lesions were present in the gallbladder and kidney of mice exposed to 17,000 ppm. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets containing 0, 312.5, 625, 1,250, 2,500, or 5,000 ppm emodin (equivalent to average daily doses of approximately 20, 40, 80, 170, or 300 mg/kg to males and females) for 14 weeks. Mean body weights of males exposed to 2,500 ppm or greater and females exposed to 1,250 ppm or greater were significantly less than those of the controls. During the first week of the study, feed consumption by males exposed to 2,500 or 5,000 ppm and females exposed to 5,000 ppm was less than that by the controls. Feed consumption by these groups was similar to that by the controls for the remainder of the study. In rats exposed to 2,500 or 5,000 ppm, there were increases in platelet counts in males and females and segmented neutrophil counts in females. Total serum protein and albumin concentrations were decreased in females exposed to 2,500 or 5,000 ppm. Relative kidney weights of rats exposed to 1,250 ppm or greater and relative lung weights of rats exposed to 625 ppm or greater were significantly increased compared to the control groups. Relative liver weights were incree increased in females exposed to 625 ppm or greater. The estrous cycle length wassignificantly increased in females exposed to 1,250 or 5,000 ppm. All male rats exposed to 1,250 ppm or greater and all exposed female rats had pigment in the renal tubules; and the severity of pigmentation generally increased with increasing exposure concentration. The incidences of hyaline droplets in the cortical epithelial cytoplasm were increased in all groups of exposed males and in females exposed to 312.5, 625, or 1,250 ppm. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were fed diets containing 0, 312.5, 625, 1,250, 2,500, or 5,000 ppm emodin (equivalent to average daily doses of approxi mately 50, 100, 190, 400, or 800 mg/kg to males and 60, 130, 240, 500, or 1,100 mg/kg to females) for 14 weeks. All mice survived to the end of the study. Mean body weights of males exposed to 2,500 or 5,000 ppm were significantly less than those of the controls. Feed consumption by exposed groups was generally similar to that by the controls. Relative kidney weights of male mice exposed to 1,250 ppm or greater, relative lung weights of males exposed to 625 ppm or greater, and relative liver weights of female mice exposed to 625 ppm or greater were increased. The incidences and severities of nephropathy were increased in males and females exposed to 1,250 ppm or greater. The incidences of renal tubule pigmentation were significantly increased in males exposed to 625 ppm or greater and in females exposed to 1,250 ppm or greater. 2-YEAR STUDY IN RATS: Groups of 65 male and 65 female rats were fed diets containing 0, 280, 830, or 2,500 ppm emodin (equivalent to average daily doses of approximately 110, 320, or 1,000 mg/kg to males and 120, 370, or 1,100 mg/kg to females) for 105 weeks. Ten male and ten female rats from each group were necropsied at 6 months. Blood samples from five male and five female rats in each group were evaluated at 3, 6, and 12 months for plasma emodin concentrations; these rats were necropsied at 12 months. Survival, Body Weights, and Feed Consumption: Survival of exposed males and females was similar to that of the controls. The mean body weights of rats in the 2,500 ppm groups were less than those of the controls beginning at week 2 of the study. Feed consumption by exposed groups was similar to that by the controls throughout the study. Pathology Findings: Three Zymbal's gland carcinomas were observed in female rats exposed to 2,500 ppm. This incidence exceeded the range observed for current historical controls and was considered an equivocal finding. At the 6- and 12-month interim evaluations and at 2 years, emodin-related increases in the incidences of renal tubule hyaline droplets occurred in all exposed groups. The incidences of renal tubule pigmentation were significantly increased in all exposed groups of males at 2 years. There were negative trends in the incidences of mononuclear cell leukemia in male and female rats, and the incidences in the 2,500 ppm groups were significantly decreased. In females exposed to 2,500 ppm, the incidence was below the historical control range; the incidence in males exposed to 2,500 ppm was at the lower end of the historical control range. 2-YEAR STUDY IN MICE: Groups of 60 male mice were fed diets containing 0, 160, 312, or 625 ppm emodin (equivalent to average daily doses of approximately 15, 35, or 70 mg/kg) for 105 weeks. Groups of 60 female mice were fed diets containing 0, 312, 625, or 1,250 ppm emodin (equivalent to average daily doses of approximately 30, 60, or 120 mg/kg) for 105 weeks. Ten male and ten female mice from each group were necropsied at 12 months. Survival, Body Weights, and Feed Consumption Survival and mean body weights of exposed males and females were similar to those of the controls. No differences in feed consumption were noted between exposed and control groups. Pathology Findings: Low incidences of renal tubule adenoma and carcinoma occurred in exposed male mice; these incidences included one carcinoma each in the 312 and 625 ppm groups. Renal tubule neoplasms are rare in male mice, and their presence in these groups suggested a possible association with emodin exposure. At the 12-month interim evaluation, the severity of nephropathy was slightly increased in males exposed to 625 ppm. Also at 12 months, the severity of nephropathy increased from minimal in the lower exposure groups to mild in females exposed to 1,250 ppm; the incidence in this group was significantly increased compared to the control group. At 2 years, the severities of nephropathy were slightly increased in males exposed to 625 ppm and females exposed to 1,250 ppm. The incidences of nephropathy were significantly increased in all exposed groups of females. At the 12-month interim evaluation, the incidences of renal tubule pigmentation were significantly increased in all exposed groups of males and in females exposed to 625 or 1,250 ppm. The severities increased with increasing exposure concentration. At 2 years, the incidences of renal tubule pigmentation were significantly increased in all exposed groups; severities increased with increasing exposure concentration. GENETIC TOXICOLOGY: Emodin was mutagenic in Salmonella typhimurium strain TA100 in the presence of S9 activation; no mutagenicity was detected in strain TA98, with or without S9. Chromosomal aberrations were induced in cultured Chinese hamster ovary cells treated with emodin, with and without S9. Three separate in vivo micronucleus tests were performed with emodin. A male rat bone marrow micronucleus test, with emodin administered by three intraperitoneal injections, gave negative results. Results of acute-exposure (intraperitoneal injection) micronucleus tests in bone marrow and peripheral blood erythrocytes of male and female mice were negative. In a peripheral blood micronucleus test on mice from the 14-week study, negative results were seen in male mice, but a weakly positive response was observed in similarly exposed females. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of emodin in male F344/N rats exposed to 280, 830, or 2,500 ppm. There was equivocal evidence of carcinogenic activity of emodin in female F344/N rats based on a marginal increase in the incidence of Zymbal's gland carcinoma. There was equivocal evidence of carcinogenic activity of emodin in male B6C3F1 mice based on a low incidence of uncommon renal tubule neoplasms. There was no evidence of carcinogenic activity of emodin in female B6C3F1 mice exposed to 312, 625, or 1,250 ppm. Exposure of rats to emodin resulted in increased incidences of renal tubule hyaline droplets and pigmentation in males, increased incidences of renal tubule hyaline droplets in females, and increased severities of renal tubule pigmentation in males and females. Emodin exposure resulted in increased incidences of renal tubule pigmentation in male and female mice and increased incidences of nephropathy in female mice. Incidences of mononuclear cell leukemia decreased in male and female rats exposed to 2,500 ppm. Synonyms: Archin; C.I. 75440; C.I. Natural Green 2; C.I. Natural Yellow 14; emodol; frangulic acid; frangula emodin; 6-methyl- 1,3,8-trihydroxyanthraquinone; Persian Berry Lake; rheum emodin; schuttgelb; 1,3,8-trihydroxy-6-methyl-9,10- anthracenedione; 1,3,8-trihydroxy-6-methylanthraquinone; 4,5,7-trihydroxy-2-methylanthraquinone.

Extracting uranium from seawater: Promising AF series adsorbents

DOE PAGES

Das, Sadananda; Oyola, Y.; Mayes, Richard T.; ...

2015-11-02

Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8more » ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.« less

Extracting uranium from seawater: Promising AF series adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sadananda; Oyola, Y.; Mayes, Richard T.

Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8more » ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.« less

Influence of terrestrial radionuclides on environmental gamma exposure in a uranium deposit in Paraíba, Brazil.

PubMed

Araújo Dos Santos Júnior, José; Dos Santos Amaral, Romilton; Simões Cezar Menezes, Rômulo; Reinaldo Estevez Álvarez, Juan; Marques do Nascimento Santos, Josineide; Herrero Fernández, Zahily; Dias Bezerra, Jairo; Antônio da Silva, Alberto; Francys Rodrigues Damascena, Kennedy; de Almeida Maciel Neto, José

2017-07-01

One of the main natural uranium deposits in Brazil is located in the municipality of Espinharas, in the State of Paraíba. This area may present high levels of natural radioactivity due to the presence of these radionuclides. Since this is a populated area, there is need for a radioecological dosimetry assessment to investigate the possible risks to the population. Based on this problem, the objective of this study was to estimate the environmental effective dose outdoors in inhabited areas influenced by the uranium deposit, using the specific activities of equivalent uranium, equivalent thorium and 40 K and conversion factors. The environmental assessment was carried using gamma spectroscopy in sixty-two points within the municipality, with a high-resolution gamma spectrometer with HPGe semiconductor detector and Be window. The results obtained ranged from 0.01 to 19.11 mSv y -1 , with an average of 2.64 mSv y -1 . These levels are, on average, 23 times higher than UNSCEAR reference levels and up to 273 times the reference value of the earth's crust for primordial radionuclides. Therefore, given the high radioactivity levels found, we conclude that there is need for further investigation to evaluate the levels of radioactivity in indoor environments, which will reflect more closely the risks of the local population. Copyright © 2017 Elsevier Inc. All rights reserved.

Toxicology and carcinogenesis studies of sodium nitrite (CAS NO. 7632-00-0) in F344/N rats and B6C3F1 mice (drinking water studies).

PubMed

2001-05-01

Sodium nitrite is used as a color fixative and preservative in meats and fish. It is also used in manufacturing diazo dyes, nitroso compounds, and other organic compounds; in dyeing and printing textile fabrics and bleaching fibers; in photography; as a laboratory reagent and a corrosion inhibitor; in metal coatings for phosphatizing and detinning; and in the manufacture of rubber chemicals. Sodium nitrite also has been used in human and veterinary medicine as a vasodilator, a bronchial dilator, an intestinal relaxant, and an antidote for cyanide poisoning. Sodium nitrite was nominated by the FDA for toxicity and carcinogenesis studies based on its widespread use in foods. Male and female F344/N rats and B6C3F1 mice were exposed to sodium nitrite (99% pure) in drinking water for 14 weeks or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, rat and mouse bone marrow, and mouse peripheral blood. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to 0, 375, 750, 1500, 3,000, or 5000 ppm sodium nitrite (equivalent to average daily doses of approximately 30, 55, 115, 200, or 310 mg sodium nitrite/kg body weight to males and 40, 80, 130, 225, or 345 mg/kg to females) in drinking water for 14 weeks. Clinical pathology study groups of 15 male and 15 female rats were exposed to the same concentrations for 70 or 71 days. One female exposed to 3000 ppm died before the end of the study. Body weights of males exposed to 3000 or 5000 ppm and females exposed to 5000 ppm were significantly less than those of the controls. Water consumption by 5000 ppm males and 3000 and 5000 ppm females was less than that by the controls at weeks 2 and 14. Clinical findings related to sodium nitrite exposure included brown discoloration in the eyes and cyanosis of the mouth, tongue, ears, and feet of males exposed to 3000 or 5000 ppm and of females exposed to 1500 ppm or greater. Reticulocyte counts were increased in males and females exposed to 3000 or 5000 ppm. The erythron was decreased on day 19 but increased by week 14 in males and females exposed to 5000 ppm. Methemoglobin concentrations were elevated in almost all exposed groups throughout the 14 week study; a no-observed-adverse-effect level was not achieved. The relative kidney and spleen weights of males and females exposed to 3000 or 5000 ppm were significantly greater than those of the controls. Sperm motility in 1500 and 5000 ppm males was significantly decreased. Increased erythropoietic activity in the bone marrow of exposed males and females was observed. The incidences of squamous cell hyperplasia of the forestomach in 5000 ppm males and females were significantly increased. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female B6C3F1 mice were exposed to 0, 375, 750, 1500, 3000, or 5000 ppm sodium nitrite (equivalent to average daily doses of approximately 90, 190, 345, 750, or 990 mg/kg to males and 120, 240, 445, 840, or 1230 mg/kg to females) in drinking water for 14 weeks. Body weights of males exposed to 5000 ppm were significantly less than those of the controls. Water consumption by males exposed to 1500 ppm or greater was slightly less than that by the controls at week 13. Relative spleen weights of 3000 and 5000 ppm males and absolute and relative heart, kidney, liver, and spleen weights of females exposed to 3000 or 5000 ppm were greater than those of the control groups. Sperm motility was decreased in 5000 ppm males, and the estrous cycles of 1500 and 5000 ppm females were significantly longer than in the controls. There were increased incidences of squamous cell hyperplasia of the forestomach in 5000 ppm males and females, extramedullary hematopoiesis of the spleen in 3000 and 5000 ppm males and 1500 ppm or greater females, and degeneration of the testis in 3000 and 5000 ppm males. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were exposed to 0, 750, 1500, or 3000 ppm sodium nitrite (equivalent to average daily doses of approximately 35, 70, or 130 mg/kg to males and 40, 8d 40, 80, or 150 mg/kg to females) in drinking water for 2 years. For toxicokinetic studies of plasma nitrite and blood methemoglobin, 10 male and 10 female special study rats were exposed to the same concentrations for 12 months. Survival of exposed groups was similar to that of the controls. Mean body weights of males and females exposed to 3000 ppm were less than those of the controls throughout the study. Water consumption by males and females exposed to 3000 ppm was less than that by the controls throughout the study, and that by the other exposed groups was generally less after week 14. The incidences of hyperplasia of the forestomach epithelium in males and females exposed to 3000 ppm were significantly greater than those in the control groups. The incidence of fibroadenoma of the mam mary gland was significantly increased in females exposed to 1500 ppm, and the incidences of multiple fibroadenoma were increased in 750 ppm and 1500 ppm females; however, these neoplasms occur with a high background incidence, and no increase was seen in the 3000 ppm group. The incidences of mononuclear cell leukemia were significantly decreased in males and females exposed to 1500 or 3000 ppm. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female B6C3F1 mice were exposed to 0, 750, 1500, or 3000 ppm sodium nitrite (equivalent to average daily doses of approximately 60, 120, or 220 mg/kg to males and 45, 90, or 165 mg/kg to females) in drinking water for 2 years. Survival of exposed groups was similar to that of the controls; mean body weights of 3000 ppm females were less than those of the controls throughout the study. Exposed groups generally consumed less water than the control groups. The incidences of squamous cell papilloma or carcinoma (combined) in the forestomach of female mice occurred with a positive trend. The incidence of hyperplasia of the glandular stomach epithelium was significantly greater in 3000 ppm males than in the controls. Sodium nitrite was mutagenic in Salmonella typhimurium strain TA100, with and without Aroclor 1254-induced hamster and rat liver S9 enzymes; no mutagenicity was observed in strain TA98. Results of acute bone marrow micronucleus tests with sodium nitrite in male rats and mice by intraperitoneal injection were negative. In addition, a peripheral blood micronucleus assay conducted with mice from the 14-week study gave negative results. Under the conditions of this 2-year drinking water study, there was no evidence of carcinogenic activity of sodium nitrite in male or female F344/N rats exposed to 750, 1500, or 3000 ppm. There was no evidence of carcinogenic activity of sodium nitrite in male B6C3F1 mice exposed to 750, 1500, or 3000 ppm. There was equivocal evidence of carcinogenic activity of sodium nitrite in female B6C3F1 mice based on the positive trend in the incidences of squamous cell papilloma or carcinoma (combined) of the forestomach. Exposure to sodium nitrite in drinking water resulted in increased incidences of epithelial hyperplasia in the forestomach of male and female rats and in the glandular stomach of male mice. Decreased incidences of mononuclear cell leukemia occurred in male and female rats.

A subchronic toxicity study of elemental Nano-Se in Sprague-Dawley rats.

PubMed

Jia, X; Li, N; Chen, J

2005-03-11

The subchronic toxicity of Nano-Se was compared with selenite and high-selenium protein in rats. Groups of Sprague-Dawley rats (12 males and 12 females per group) were fed diets containing Nano-Se, selenite and high-selenium protein at concentrations of 0, 2, 3, 4 and 5 ppm Se, respectively, for 13 weeks. Clinical observations were made and body weight and food consumption were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry determination. Histopathological examination was performed on selected tissues. At the two higher doses (4 and 5 ppm Se), significant abnormal changes were found in body weight, hematology, clinical chemistry, relative organ weights and histopathology parameters. However, the toxicity was more pronounced in the selenite and high-selenium protein groups than the Nano-Se group. At the dose of 3 ppm Se, significant growth inhibition and degeneration of liver cells were found in the selenite and high-selenium protein groups. No changes attributable to administration of Nano-Se at the dose of 3 ppm Se were found. Taken together, the no-observed-adverse-effect level (NOAEL) of Nano-Se in male and female rats was considered to be 3 ppm Se, equivalent to 0.22 mg/kg bw/day for males and 0.33 mg/kg bw/day for females. On the other hand, the NOAELs of selenite and high-selenium protein in males and females were considered to be 2 ppm Se, equivalent to 0.14 mg/kg bw/day for males and 0.20 mg/kg bw/day for females. In addition, studies have shown that Nano-Se has a similar bioavailability in rat, and much less acute toxicity in mice compared with selenite. In conclusion, Nano-Se is less toxic than selenite and high-selenium protein in the 13-week rat study.

Development of a transportable neutron activation analysis system to quantify manganese in bone in vivo: feasibility and methodology.

PubMed

Liu, Yingzi; Koltick, David; Byrne, Patrick; Wang, Haoyu; Zheng, Wei; Nie, Linda H

2013-12-01

This study was conducted to investigate the methodology and feasibility of developing a transportable neutron activation analysis (NAA) system to quantify manganese (Mn) in bone using a portable deuterium-deuterium (DD) neutron generator as the neutron source. Since a DD neutron generator was not available in our laboratory, a deuterium-tritium (DT) neutron generator was used to obtain experimental data and validate the results from Monte Carlo (MC) simulations. After validation, MC simulations using a DD generator as the neutron source were then conducted. Different types of moderators and reflectors were simulated, and the optimal thicknesses for the moderator and reflector were determined. To estimate the detection limit (DL) of the system, and to observe the interference of the magnesium (Mg) γ line at 844 keV to the Mn γ line at 847 keV, three hand phantoms with Mn concentrations of 30 parts per million (ppm), 150 ppm, and 500 ppm were made and irradiated by the DT generator system. The Mn signals in these phantoms were then measured using a 50% high-efficiency high-purity germanium (HPGe) detector. The DL was calculated to be about 4.4 ppm for the chosen irradiation, decay, and measurement time. This was calculated to be equivalent to a DL of about 3.3 ppm for the DD generator system. To achieve this DL with one 50% high-efficiency HPGe detector, the dose to the hand was simulated to be about 37 mSv, with the total body equivalent dose being about 23µSv. In conclusion, it is feasible to develop a transportable NAA system to quantify Mn in bone in vivo with an acceptable radiation exposure to the subject.

Development of a transportable neutron activation analysis system to quantify manganese in bone in vivo: feasibility and methodology

PubMed Central

Liu, Yingzi; Koltick, David; Byrne, Patrick; Wang, Haoyu; Zheng, Wei; Nie, Linda H

2014-01-01

This study was conducted to investigate the methodology and feasibility of developing a transportable neutron activation analysis (NAA) system to quantify manganese (Mn) in bone using a portable deuterium–deuterium (DD) neutron generator as the neutron source. Since a DD neutron generator was not available in our laboratory, a deuterium–tritium (DT) neutron generator was used to obtain experimental data and validate the results from Monte Carlo (MC) simulations. After validation, MC simulations using a DD generator as the neutron source were then conducted. Different types of moderators and reflectors were simulated, and the optimal thicknesses for the moderator and reflector were determined. To estimate the detection limit (DL) of the system, and to observe the interference of the magnesium (Mg) γ line at 844 keV to the Mn γ line at 847 keV, three hand phantoms with Mn concentrations of 30 parts per million (ppm), 150 ppm, and 500 ppm were made and irradiated by the DT generator system. The Mn signals in these phantoms were then measured using a 50% high-efficiency high-purity germanium (HPGe) detector. The DL was calculated to be about 4.4 ppm for the chosen irradiation, decay, and measurement time. This was calculated to be equivalent to a DL of about 3.3 ppm for the DD generator system. To achieve this DL with one 50% high-efficiency HPGe detector, the dose to the hand was simulated to be about 37 mSv, with the total body equivalent dose being about 23μSv. In conclusion, it is feasible to develop a transportable NAA system to quantify Mn in bone in vivo with an acceptable radiation exposure to the subject. PMID:24165395

Deep liquid-chromatographic purification of uranium extract from technetium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Volk, V.; Dvoeglazov, K; Podrezova, L.

The recycling of uranium in the nuclear fuel cycle requires the removal of a number of radioactive and stable impurities like {sup 99}Tc from spent fuels. In order to improve the grade of uranium extract purification from technetium the method of liquid chromatography and the apparatus for its performance have been developed. Process of technetium extraction and concentrating in aqueous solution containing reducing agent has been studied on simulated solutions (U-Tc-HNO{sub 3}-30% TBP-isoparM). The dynamic tests of the method have been carried out on the laboratory unit. Solution of diformyl-hydrazine in nitric acid was used as a stationary phase. Silicamore » gel with specific surface of 186 m{sup 2}/g was used as a carrier of the stationary phase. It is shown that the volume of purified extract increases as the solution temperature increases, concentration of reducing agent increases and extract flow rate decreases. It is established that the technetium content in uranium by this method could achieve a value below 0.3 ppm. Some variants of overload and composition of the stationary phase containing the extracted technetium have been offered and tested. It is defined that the method provides reduction of processing medium-active wastes by more than 10 times during finish refining process. (authors)« less

Irradiation of organic matter by uranium decay in the Alum Shale, Sweden

NASA Astrophysics Data System (ADS)

Lewan, M. D.; Buchardt, B.

1989-06-01

The Alum Shale of Sweden contains black shales with anomalously high uranium concentrations in excess of 100 ppm. Syngenetic or early diagenetic origin of this uranium indicates that organic matter within these shales has been irradiated by decaying uranium for approximately 500 Ma. Radiation-induced polymerization of alkanes through a free-radical cross-linking mechanism appears to be responsible for major alterations within the irradiated organic matter. Specific radiation-induced alterations include generation of condensate-like oils at reduced yields from hydrous pyrolysis experiments, decrease in atomic H/C ratios of kerogens, decrease in bitumen/organic-carbon ratios, and a relative increase in low-molecular weight triaromatic steroid hydrocarbons. Conversely, stable carbon isotopes of kerogens, reflectance of vitrinite-like macerais, oil-generation kinetics, and isomerization of 20R to 20S αα C 29-steranes were not affected by radiation. The radiation dosage needed to cause the alterations observed in the Alum Shale has been estimated to be in excess of 10 5 Mrads with respect to organic carbon. This value is used to estimate the potential for radiation damage to thermally immature organic matter in black shales through the geological rock record. High potential for radiation damage is not likely in Cenozoic and Mesozoic black shales but becomes more likely in lower Paleozoic and Precambrian black shales.

Verifying the Presence of Low Levels of Neptunium in a Uranium Matrix with Electron Energy-Loss Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buck, Edgar C.; Douglas, Matthew; Wittman, Richard S.

2010-01-01

This paper examines the problems associated with the analysis of low levels of neptunium (Np) in a uranium (U) matrix with electron energy-loss spectroscopy (EELS) on the transmission electron microscope (TEM). The detection of Np in a matrix of uranium (U) can be impeded by the occurrence of a plural scattering event from U (U-M5 + U-O4,5) that results in severe overlap on the Np-M5 edge at 3665 eV. Low levels (1600 - 6300 ppm) of Np can be detected in U solids by confirming the energy gap between the Np-M5 and Np-M4 edges is at 184 eV and showingmore » that the M4/M5 ratio for the Np is smaller than that for U. The Richardson-Lucy deconvolution method was applied to energy-loss spectral images and was shown to increase the signal to noise. This method also improves the limits of detection for Np in a U matrix.« less

Parts per billion detection of uranium with a porphyrinoid-containing nanoparticle and in vivo photoacoustic imaging

DOE PAGES

Ho, I-Ting; Sessler, Jonathan L.; Gambhir, Sanjiv Sam; ...

2015-04-01

Chemical tools that can report radioactive isotopes would be of interest to the defense community. Here in this paper we report –250 nm polymeric nanoparticles containing porphyrinoid macrocycles with and without pre-complexed depleted uranium and demonstrate that the latter species may be detected easily and with high sensitivity via photoacoustic imaging. The porphyrinoid macrocycles used in the present study are non-aromatic in the absence of the uranyl cation, but aromatic after cation complexation. We solubilized both the freebase and metalated forms of the macrocycles in poly(lactic-co-glycolic acid) and found a peak in the photoacoustic spectrum at 910 nm excitation inmore » the case of the uranyl complex. The signal was stable for at least 15 minutes and allowed detection of uranium concentrations down to 6.2 ppb (5.7 nM) in vitro and 0.57 ppm (19 fCi; 0.52 μM) in vivo. Furthermore, to the best of our knowledge, this is the first report of a nanoparticle that detects an actinide cation via photoacoustic imaging.« less

Uraniferous bitumen nodules in the Talvivaara Ni-Zn-Cu-Co deposit (Finland): influence of metamorphism on uranium mineralization in black shales

NASA Astrophysics Data System (ADS)

Lecomte, Andreï; Cathelineau, Michel; Deloule, Etienne; Brouand, Marc; Peiffert, Chantal; Loukola-Ruskeeniemi, Kirsti; Pohjolainen, Esa; Lahtinen, Hannu

2014-04-01

In the central part of the Fennoscandian Shield, the Talvivaara Ni-Zn-Cu-Co deposit, hosted by Palaeoproterozoic metamorphosed black schists, contains low uranium concentrations ranging from 10 to 30 ppm. The Talvivaara black schists were deposited 2.0-1.9 Ga ago and underwent subsequent metamorphism during the 1.9-1.79 Ga Svecofennian orogeny. Anhedral uraninite crystals rimmed by bitumen constitute the main host of uranium. U-Pb secondary ion mass spectrometry dating indicates that uraninite crystals were formed between 1,878 ± 17 and 1,871 ± 43 Ma, during peak metamorphism. Rare earth element patterns and high Th content (average 6.38 wt%) in disseminated uraninite crystals indicate that U was concentrated during high temperature metamorphism (>400 °C). The formation of bitumen rims around uraninite may be explained by two distinct scenarios: (a) a transport of U coincident with the migration of hydrocarbons or (b) post-metamorphic formation of bitumen rims, through radiolytic polymerization of gaseous hydrocarbons at the contact with uraninite.

Synthesis and sintering of UN-UO2 fuel composites

NASA Astrophysics Data System (ADS)

Jaques, Brian J.; Watkins, Jennifer; Croteau, Joseph R.; Alanko, Gordon A.; Tyburska-Püschel, Beata; Meyer, Mitch; Xu, Peng; Lahoda, Edward J.; Butt, Darryl P.

2015-11-01

The design and development of an economical, accident tolerant fuel (ATF) for use in the current light water reactor (LWR) fleet is highly desirable for the future of nuclear power. Uranium mononitride has been identified as an alternative fuel with higher uranium density and thermal conductivity when compared to the benchmark, UO2, which could also provide significant economic benefits. However, UN by itself reacts with water at reactor operating temperatures. In order to reduce its reactivity, the addition of UO2 to UN has been suggested. In order to avoid carbon impurities, UN was synthesized from elemental uranium using a hydride-dehydride-nitride thermal synthesis route prior to mixing with up to 10 wt% UO2 in a planetary ball mill. UN and UN - UO2 composite pellets were sintered in Ar - (0-1 at%) N2 to study the effects of nitrogen concentration on the evolved phases and microstructure. UN and UN-UO2 composite pellets were also sintered in Ar - 100 ppm N2 to assess the effects of temperature (1700-2000 °C) on the final grain morphology and phase concentration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaques, Brian J.; Watkins, Jennifer; Croteau, Joseph R.

In this study, the design and development of an economical, accident tolerant fuel (ATF) for use in the current light water reactor (LWR) fleet is highly desirable for the future of nuclear power. Uranium mononitride has been identified as an alternative fuel with higher uranium density and thermal conductivity when compared to the benchmark, UO 2, which could also provide significant economic benefits. However, UN by itself reacts with water at reactor operating temperatures. In order to reduce its reactivity, the addition of UO 2 to UN has been suggested. In order to avoid carbon impurities, UN was synthesized frommore » elemental uranium using a hydride-dehydride-nitride thermal synthesis route prior to mixing with up to 10 wt% UO 2 in a planetary ball mill. UN and UN – UO 2 composite pellets were sintered in Ar – (0–1 at%) N 2 to study the effects of nitrogen concentration on the evolved phases and microstructure. UN and UN-UO 2 composite pellets were also sintered in Ar – 100 ppm N 2 to assess the effects of temperature (1700–2000 °C) on the final grain morphology and phase concentration.« less

Ground gamma-ray spectrometric studies of El-Sahu area, southwestern Sinai, Egypt

NASA Astrophysics Data System (ADS)

Abdrabboh, Ahmad M.

2017-12-01

Based on the previous airborne gamma-ray spectrometric study carried out in southwestern Sinai area, El Sahu area was selected for detail ground gamma-ray spectrometric survey. This area is considered as a good target for radioactive mineral exploration. The study area is exposed in a Paleozoic basin covered by different rocks (ranging from Precambrian to Quaternary). The ground gamma-ray spectrometric survey has been conducted along the study area through random survey. The resultant gamma-ray spectrometric maps show different levels of radioactivity over the studied area, which reflect contrasting radioelement contents for the exposed various rock types. The studied area possesses total count ranging from 2.6 to 326 Ur, 0.1 to 2.8% K, 1.7 to 316 ppm eU and 0.9 to 47.5 ppm eTh. The highest uranium concentrations are located in the northern and southern parts of El Sahu area. They are mainly associated with Um Bogma Formation occurrences. Uranium ratio maps (eU/K and eU/eTh) as well as ternary maps show sharp increase of eU content over both potassium and thorium contents associated with the ENE and NNW trends in Um Bogma Formation, indicating an increase in the U-potentiality than the surrounding rocks. This indicates that the mineralization in the study area may be structurally-controlled.

Understanding Uranium Behavior in a Reduced Aquifer

NASA Astrophysics Data System (ADS)

Janot, N.; Lezama-Pacheco, J. S.; Williams, K. H.; Bernier-Latmani, R.; Long, P. E.; Davis, J. A.; Fox, P. M.; Yang, L.; Giammar, D.; Cerrato, J. M.; Bargar, J.

2012-12-01

Uranium contamination of groundwater is a concern at several US Department of Energy sites, such Old Rifle, CO. Uranium transport in the environment is mainly controlled by its oxidation state, since oxidized U(VI) is relatively mobile, whereas U(IV) is relatively insoluble. Bio-remediation of contaminated aquifers aims at immobilizing uranium in a reduced form. Previous laboratory and field studies have shown that adding electron donor (lactate, acetate, ethanol) to groundwater stimulates the activity of metal- and sulfate-reducing bacteria, which promotes U(VI) reduction in contaminated aquifers. However, obtaining information on chemical and physical forms of U, Fe and S species for sediments biostimulated in the field, as well as kinetic parameters such as U(VI) reduction rate, is challenging due to the low concentration of uranium in the aquifers (typically < 10 ppm) and the expense of collecting large number of cores. An in-situ technique has been developed for studying uranium, iron and sulfur reduction dynamics during such bioremediation episodes. This technique uses in-well columns to obtain direct access to chemical and physical forms of U(IV) produced in the aquifer, evolving microbial communities, and trace and major ion groundwater constituents. While several studies have explored bioreduction of uranium under sulfate-reducing conditions, less attention has been paid to the initial iron-reducing phase, noted as being of particular importance to uranium removal. The aim of this work was to assess the formation of U(IV) during the early stages of a bio-remediation experiment at the Old Rifle site, CO, from early iron-reducing conditions to the transition to sulfate-reducing conditions. Several in-well chromatographic columns packed with sediment were deployed and were sampled at different days after the start of bio-reduction. X-ray absorption spectroscopy and X-ray microscopy were used to obtain information on Fe, S and U speciation and distribution. Chemical extractions of the reduced sediments have also been performed, to determine the rate of Fe(II) and U(IV) accumulation.

Distribution of gold, tellurium, silver, and mercury in part of the Cripple Creek district, Colorado

USGS Publications Warehouse

Gott, Garland Bayard; McCarthy, J.H.; Van Sickle, G.H.; McHugh, J.B.

1967-01-01

Geochemical exploration studies were undertaken in the Cripple Creek district to test the possibility that large low-grade gold deposits might be found. Surface rock samples taken throughout the district indicate that the volcanic rocks between the productive veins contain an average of about 0.6 ppm (part per million) gold. In an area above 3,800 feet long and 500 feet wide near the Cresson mine in the south-central part of the district, scattered surface samples show that the rocks contain an average of 2.5 ppm gold, equivalent to $2.50 per ton. Inasmuch as veins that contain more than 2.5 ppm may also exist in the area, systematic sampling by trenching and drilling is warranted.

The importance of colloids and mires for the transport of uranium isotopes through the Kalix River watershed and Baltic Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porcelli, D.; Wasserburg, G.J.; Andersson, P.S.

The importance of colloids and organic deposits for the transport of uranium isotopes from continental source regions and through the estuarine environment was investigated in the mire-rich Kalix River drainage basin in northern Sweden and the Baltic Sea. Ultrafiltration techniques were used to separate uranium and other elements associated with colloids > 10 kD and >3 kD from {open_quotes}solute{close_quotes} uranium and provided consistent results and high recovery rates for uranium as well as for other elements from large volume samples. Uranium concentrations in 0.45 {mu}m-filtered Kalix River water samples increased by a factor of 3 from near the headwaters inmore » the Caledonides to the river mouth while major cation concentrations were relatively constant. {sup 234}U {sup 238}U ratios were high ({delta}{sup 234}U = 770-1500) throughout the basin, without showing any simple pattern, and required a supply of {sup 234}U-rich water. Throughout the Kalix River, a large fraction (30-90%) of the uranium is carried by >10 kD colloids, which is compatible with uranium complexation with humic acids. No isotopic differences were found between colloid-associated and solute uranium. Within the Baltic Sea, about half of the uranium is removed at low salinities. The proportion that is lost is equivalent to that of river-derived colloid-bound uranium, suggesting that while solute uranium behaves conservatively during estuarine mixing, colloid-bound uranium is lost due to rapid flocculation of colloidal material. The association of uranium with colloids therefore may be an important parameter in determining uranium estuarine behavior. Mire peats in the Kalix River highly concentrate uranium and are potentially a significant source of recoil {sup 234}U to the mirewaters and river waters. However, mirewater data clearly demonstrate that only small {sup 234}U/{sup 238}U shifts are generated relative to inflowing groundwater. 63 refs., 8 figs., 3 tabs.« less

ANALYSIS OF 2H-EVAPORATOR SCALE WALL [HTF-13-82] AND POT BOTTOM [HTF-13-77] SAMPLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L.

2013-06-21

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2Hevaporatormore » pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxy-hydroxide mineral). On “as received” basis, the bottom pot section scale sample contained an average of 2.59E+00 ± 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 ± 1.48E-02 %, while the wall sample contained an average of 4.03E+00 ± 9.79E-01 wt % total uranium with a U-235 enrichment of 6.03E-01% ± 1.66E-02 wt %. The bottom pot section scale sample analyses results for Pu-238, Pu-239, and Pu-241 are 3.16E- 05 ± 5.40E-06 wt %, 3.28E-04 ± 1.45E-05 wt %, and <8.80E-07 wt %, respectively. The evaporator wall scale samples analysis values for Pu-238, Pu-239, and Pu-241 averages 3.74E-05 ± 6.01E-06 wt %, 4.38E-04 ± 5.08E-05 wt %, and <1.38E-06 wt %, respectively. The Pu-241 analyses results, as presented, are upper limit values. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241. The applicable method for calculation of equivalent U-235 will be determined in the NCSA.« less

PROGRESS ON THE STUDY OF THE URANIUM-ALUMINUM-IRON CONSTITUTION DIAGRAM FOR THE PERIOD APRIL 1-AUGUST 31, 1963

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, R.B.

Progress is reported of a research program on deterinining the U--Al-- Fe constitution diagram up to approximates 1000 ppm each of Al and Fe. Results are reported of metallographic examinations of U--Al, U--Fe, and U--Al--Fe alloys, and tentative phase diagrams are given for all three systems. Lattice parameters and electrical resistances were measured in an effort to determine the solid solubilities of Al and Fe in U. (D.L.C.)

Extracting Uranium from Seawater: Promising AF Series Adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Oyola, Y.; Mayes, Richard T.

A new family of high-surface-area polyethylene fiber adsorbents named the AF series was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series adsorbents were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/comonomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154-354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44 M KOH at 80 °C followed by screening at ORNL with sodium-based synthetic aqueous solution, spiked withmore » 8 ppm uranium. The uranium adsorption capacity in simulated seawater screening ranged from 170 to 200 g-U/kg-ads irrespective of %DOG. A monomer/comonomer molar ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through column experiments to determine uranium loading capacity with varying KOH conditioning times at 80 °C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1 and 3 h of KOH conditioning at 80 °C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 1 to 3 h at 80 °C resulted in a 22-27% decrease in uranium adsorption capacity in seawater.« less

The Permo-Triassic uranium deposits of Gondwanaland

NASA Astrophysics Data System (ADS)

le Roux, J. P.; Toens, P. D.

The world's uranium provinces are time bound and occur in five distinct periods ranging from the Proterozoic to the Recent. One of these periods embraces the time of Gondwana sedimentation and probably is related to the proliferation of land plants from the Devonian on-ward. Decaying vegetal matter produced reducing conditions that enhanced uranium precipitation. The association of uranium with molassic basins adjacent to uplifted granitic and volcanic arcs suggests that lithospheric plate subduction, leading to anatexis of basement rocks and andesitic volcanism, created favorable conditions for uranium mineralization. Uranium occurrences of Gondwana age are of four main types: sandstone-hosted, coal-hosted, pelite-hosted, and vein-type deposits. Sandstone-hosted deposits commonly occur in fluviodeltaic sediments and are related to the presence of organic matter. These deposits commonly are enriched in molybdenum and other base metal sulfides and have been found in South Africa, Zimbabwe, Zambia, Angola, Niger, Madagascar, India, Australia, Argentina, and Brazil. Coalhosted deposits contain large reserves of uranium but are of low grade. In Africa they are mostly within the Permian Ecca Group and its lateral equivalents, as in the Springbok Flats, Limpopo, Botswana, and Tanzania basins. Uraniferous black shales are present in the Gabon and Amazon basins but grades are low. Vein-type uranium is found in Argentina, where it occurs in clustered veins crosscutting sedimentary rocks and quartz porphyries.

Burial of redox-sensitive metals and organic matter in the equatorial Indian Ocean linked to precession

NASA Astrophysics Data System (ADS)

Pailler, Delphine; Bard, Edouard; Rostek, Frauke; Zheng, Yan; Mortlock, Richard; van Geen, Alexander

2002-03-01

Authigenic metals (uranium, cadmium, and molybdenum), organic carbon (OC) and total C37 alkenone (totC37) concentrations were measured for the last 350 kyr in core MD900963, located in the eastern equatorial Arabian Sea. Authigenic metal concentrations on a carbonate-free basis range between 1 and 17 ppm, 0.5 and 6 ppm, and 0.5 and 4 ppm for U, Cd, and Mo, respectively. The profiles are characterized by well-defined 23 kyr cycles between oxic and mildly suboxic conditions. The redox-sensitive metal profiles also follow variations in the concentrations of OC (0.2-0.9%) and alkenones (0.2-6.7 ppm). The coupled variations in inorganic and organic constituents are attributed to a 23-kyr cycle in primary production above site MD900963, as suggested by clear correlations with independent micropaleontologic proxies (primary productivity indices based on foraminifera and coccoliths and fragmentation of foraminiferal shells). The 23-kyr cycles do appear to be primarily driven by productivity rather than changes in bottom water oxygen. Comparison with other records indicates that if this interpretation is correct, productivity variations across much of the Indian Ocean have been dominated by precessional forcing, with high productivity in phase with low summer insolation in the Northern Hemisphere. This interpretation contrasts with the traditional attribution of enhanced productivity in the Indian Ocean with periods of high summer insolation.

Contaminant dispersion at the rehabilitated Mary Kathleen uranium mine, Australia

NASA Astrophysics Data System (ADS)

Lottermoser, B. G.; Ashley, P. M.; Costelloe, M. T.

2005-09-01

This study reports on the transfer of contaminants from waste rock dumps and mineralised ground into soils, sediments, waters and plants at the rehabilitated Mary Kathleen uranium mine in semi-arid northwest Queensland. Numerous waste rock dumps were partly covered with benign soil and the open pit mine was allowed to flood. The mineralised and waste calc-silicate rock in the open pit and dumps has major (>1 wt%) Ca, Fe and Mg, minor (>1,000 ppm) Ce, La, Mn, P and S, subminor (>100 ppm) Ba, Cu, Th and U, and trace (<100 ppm) As, Ni, Pb, Y and Zn values. Consequently, chemical and physical weathering processes have acted on waste rock and on rock faces within the open pit, mobilising many elements and leading to their dispersion into soils, stream sediments, pit water and several plant species. Chemical dispersion is initiated by sulfide mineral breakdown, generation of sulfuric acid and formation of several soluble, transient sulfate minerals as evaporative efflorescent precipitates. Radiation doses associated with the open pit average 5.65 mSv year-1; waste dumps commonly have lower values, especially where soil-covered. Surface pit water is slightly acid, with high sulfate values accompanied by levels of U, Cu and Ni close to or above Australian water guideline values for livestock. Dispersion of U and related elements into soils and stream sediments occurs by physical (erosional) processes and from chemical precipitation. Plants growing in the mine void, on waste dumps and contaminated soil display evidence of biological uptake of U, LREE, Cu and Th and to a lesser degree of As, Ni, Pb, Y and Zn, with values being up to 1-2 orders of magnitude above background sites for the same species. Although rehabilitation procedures have been partly successful in reducing dispersion of U and related elements into the surrounding environment, it is apparent that 20 years after rehabilitation, there is significant physical and chemical mobility, including transfer into plants.

40 CFR 761.274 - Reporting PCB concentrations in samples.

Code of Federal Regulations, 2014 CFR

2014-07-01

... concentrations for non-liquid PCBs on a dry weight basis as micrograms of PCBs per gram of sample (ppm by weight... quotient by the total number of micrograms of PCBs on the surface to obtain the equivalent measurement of...

40 CFR 761.274 - Reporting PCB concentrations in samples.

Code of Federal Regulations, 2011 CFR

2011-07-01

... concentrations for non-liquid PCBs on a dry weight basis as micrograms of PCBs per gram of sample (ppm by weight... quotient by the total number of micrograms of PCBs on the surface to obtain the equivalent measurement of...

40 CFR 761.274 - Reporting PCB concentrations in samples.

Code of Federal Regulations, 2012 CFR

2012-07-01

... concentrations for non-liquid PCBs on a dry weight basis as micrograms of PCBs per gram of sample (ppm by weight... quotient by the total number of micrograms of PCBs on the surface to obtain the equivalent measurement of...

Variations of radon concentration in the atmosphere. Gamma dose rate

NASA Astrophysics Data System (ADS)

Tchorz-Trzeciakiewicz, D. E.; Solecki, A. T.

2018-02-01

The purposes of research were following: observation and interpretation of variations of radon concentration in the atmosphere - vertical, seasonal, spatial and analysis of relation between average annual radon concentration and ground natural radiation and gamma dose rate. Moreover we wanted to check the occurrence of radon density currents and the possibility of radon accumulation at the foot of the spoil tip. The surveys were carried out in Okrzeszyn (SW Poland) in the area of the spoil tip formed during uranium mining that took place in 60's of 20th century. The measurements were carried out in 20 measurements points at three heights: 0.2 m, 1 m and 2 m a.g.l. using SSNTD LR-115. The survey lasted one year and detectors were exchanged at the beginning of every season. Uranium eU (ppm), thorium eTh (ppm) and potassium K (%) contents were measured using gamma ray spectrometer Exploranium RS-230, ambient gamma dose rate using radiometer RK-100. The average radon concentration on this area was 52.8 Bq m-3. The highest radon concentrations were noted during autumn and the lowest during winter. We observed vertical variations of radon concentration. Radon concentrations decreased with increase of height above ground level. The decrease of radon with increase of height a.g.l. had logarithmic character. Spatial variations of radon concentrations did not indicate the occurrence of radon density currents and accumulation of radon at the foot of the spoil tip. The analysis of relation between average radon concentrations and ground natural radiation (uranium and thorium content) or gamma dose rate revealed positive relation between those parameters. On the base of results mentioned above we suggested that gamma spectrometry measurements or even cheaper and simpler ambient gamma dose rate measurements can be a useful tool in determining radon prone areas. This should be confirmed by additional research.

Effect of baking and frying on the in vivo toxicity to rats of cornmeal containing fumonisins.

PubMed

Voss, Kenneth A; Meredith, Filmore I; Bacon, Charles W

2003-08-27

Fumonisins are mycotoxins produced by Fusarium verticillioides (=F. moniliforme) and other Fusarium species. They are found in corn and corn-based foods. Cooking decreases fumonisin concentrations in food products under some conditions; however, little is known about how cooking effects biological activity. Baked cornbread, pan-fried corncakes, and deep-fried fritters were made from cornmeal that was spiked with 5% w/w F. verticillioides culture material (CM). The cooked materials and the uncooked CM-spiked cornmeal were fed to male rats (n = 5/group) for 2 weeks at high (20% w/w spiked cornmeal equivalents) or low (2% w/w spiked cornmeal equivalents) doses. A control group was fed a diet containing 20% w/w unspiked cornmeal. Toxic response to the uncooked CM-spiked cornmeal and the cooked products included decreased body weight gain (high-dose only), decreased kidney weight, and microscopic kidney and liver lesions of the type caused by fumonisins. Fumonisin concentration, as determined by HPLC analysis, in the 20% w/w pan-fried corncake diet [92.2 ppm of fumonisin B(1) (FB(1))] was slightly, but not statistically significantly, lower than those of the 20% w/w baked cornbread (132.2 ppm of FB(1)), deep-fried fritter (120.2 ppm of FB(1)) and CM-spiked cornmeal (130.5 of ppm FB(1)) diets. Therefore, baking and frying had no significant effect on the biological activity or concentration of fumonisins in these corn-based products, and the results provided no evidence for the formation of novel toxins or "hidden" fumonisins during cooking.

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.

Effect of water on hydrogen permeability. [Stirling engines

NASA Technical Reports Server (NTRS)

Hulligan, D. D.; Tomazic, W. A.

1984-01-01

Doping of hydrogen with CO or CO2 was developed to reduce hydrogen permeation in Stirling engines by forming low permeability oxide coatings in the heater tubes. An end product of this process is water - which can condense in the cold parts of the engine system. If the water vapor is reduced to a low enough level, the hydrogen can reduce the oxide coating resulting in increased permeability. The equilibrium level of water (oxygen bearing gas) required to avoid reduction of the oxide coating was investigated. Results at 720 C and 13.8 MPa have shown that: (1) pure hydrogen will reduce the coating; (2) 500 ppm CO (500 ppm water equivalent) does not prevent the reduction; and (3) 500 ppm CO2 (1000 ppm water) appears to be close to the equilibrium level. Further tests are planned to define the equilibrium level more precisely and to extend the data to 820 C and 3.4, 6.9, and 13.8 MPa.

Enhancing uranium uptake by amidoxime adsorbent in seawater: An investigation for optimum alkaline conditioning parameters

DOE PAGES

Das, Sadananda; Tsouris, Costas; Zhang, Chenxi; ...

2015-09-07

A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 °C). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentration ofmore » ~7–8 ppm and pH 8. Fourier transform infrared spectroscopy and solid-state NMR analyses indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 °C resulted in an increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. The scanning electron microscopy showed that long conditioning times may also lead to adsorbent degradation.« less

Enhancing Uranium Uptake by Amidoxime Adsorbent in Seawater: An investigation for optimum alkaline conditioning parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, S.; Tsouris, Constantinos; Zhang, C.

2016-04-20

A high-surface-area polyethylene-fiber adsorbent (AF160-2) has been developed at the Oak Ridge National Laboratory (ORNL) by radiation-induced graft polymerization of acrylonitrile and itaconic acid. The grafted nitriles were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with potassium hydroxide (KOH) by varying different reaction parameters such as KOH concentration (0.2, 0.44, and 0.6 M), duration (1, 2, and 3 h), and temperature (60, 70, and 80 ºC). Adsorbent screening was then performed with simulated seawater solutions containing sodium chloride and sodium bicarbonate, at concentrations found in seawater, and uranium nitrate at a uranium concentrationmore » of ~ 7-8 ppm and pH 8. FTIR and solid state NMR indicated that a fraction of amidoxime groups was hydrolyzed to carboxylate during KOH conditioning. The uranium adsorption capacity in the simulated seawater screening solution gradually increased with conditioning time and temperature for all KOH concentrations. It was also observed that the adsorption capacity increased with an increase in concentration of KOH for all the conditioning times and temperatures. AF160-2 adsorbent samples were also tested with natural seawater using flow-through experiments to determine uranium adsorption capacity with varying KOH conditioning time and temperature. Based on uranium loading capacity values of several AF160-2 samples, it was observed that changing KOH conditioning time from 3 to 1 h at 60, 70, and 80 ºC resulted in increase of the uranium loading capacity in seawater, which did not follow the trend found in laboratory screening with stimulated solutions. Longer KOH conditioning times lead to significantly higher uptake of divalent metal ions, such as calcium and magnesium, which is a result of amidoxime conversion into less selective carboxylate. Scanning electron microscopy showed that long conditioning times may also lead to adsorbent degradation« less

AERORADIOACTIVITY SURVEY AND AREAL GEOLOGY OF THE GEORGIA NUCLEAR LABORATORY AREA, NORTHERN GEORGIA (ARMS-I)

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKallor, J.A.

1962-01-01

An airborne gamma-radioactivity survey of about 7000 square miles around the Georgia Nuclear Laboratory (GNL) in Dawson County, Ga., was made by the U. S. Geological Survey in cooperation with the Division of Biology and Medicine, U. S. Atomic Energy Commission. The project was flown perpendicular to the regional strike at a nominal elevation of 500 ft above the ground with a flight-line spacing of 1 mile. Radioactivity contacts shown on a 1:250,000 map delineate areas of similar radioactivity, which, in general, trend northeast, parallel to the geologic strike. Many, but not all, formations correlate closely with radioactivity units. Changesmore » of radioactivity within some formations may indicate facies changes. In the GNL area the Cartersville fault, which dlosely coincides with a prominent radioactivity contact, separates the Valley and Ridge physiographic province from the Piedmont to the east. Within the Valley and Ridge province bedrock consists of sedimentary rocks of Paleozoic age; the radioactivity is from 300 to 900 counts per second (cps). Areas of limestone and dolomite are characterized by radioactivity lows, usually less than 500 cps. Most areas of shale have a radioactivity of 600 to 900 cps. Bedrock in the Piedmont consists mainly of igneous and metamorphic rocks of Precambrian and Palezoic ages, and the radioactivity ranges from about 250 to 2000 cps. The least radioactive rocks (250 to 500 cps) are hornblende gneiss, dioritic injection gneiss, and some of the granitic gneiss. The most radioactive rock is the augen gneiss in Bartow and Cherokee Counties (1000 to 2000 cps). Some of the granitic gneiss, biotite gneiss and schist, and the Talladega Slate have a radioactivity of slightly more than 1000 cps. Composite samples of surficial material were collected from sites directly under the flight path of the aircraft. After analysis for equivalent uranium based upon the number of counts recorded by geiger tubes, the samples were stored for future reference. The equivalent uranium was plotted against cps obtained from the aerial surveying. From 600 cps, which corresponds to slightiy more than 0.001 percent equivalent uranium, to 1600 cps, each 200-cps increase corresponds to an increase of almost 0.001 percent equivalent uranium. (auth)« less

Sorption and coprecipitation of trace concentrations of thorium with various minerals under conditions simulating an acid uranium mill effluent environment

USGS Publications Warehouse

Landa, Edward R.; Le, Anh H.; Luck, Rudy L.; Yeich, Philip J.

1995-01-01

Sorption of thorium by pre-existing crystals of anglesite (PbSO4), apatite (Ca5(PO4)3(HO)), barite (BaSO4), bentonite (Na0.7Al3.3Mg0.7Si8O20(OH)4), celestite (SrSO4), fluorite (CaF2), galena (PbS), gypsum (CaSO4·2H2O), hematite (Fe2O3), jarosite (KFe3(SO4)2(OH)6), kaolinite (Al2O3·2SiO2·2H2O), quartz (SiO2) and sodium feldspar (NaAlSi3O8) was studied under conditions that simulate an acidic uranium mill effluent environment. Up to 100% removal of trace quantitiees of thorim (approx. 1.00 ppm in 0.01 N H2SO4) from solution occurred within 3 h with fluorite and within 48 h in the case of bentonite. Quartz, jarosite, hematite, sodium feldspar, gypsum and galena removed less than 15% of the thorium from solution. In the coprecipitation studies, barite, anglesite, gypsum and celestite were formed in the presence of thorium (approx. 1.00 ppm). Approximately all of the thorium present in solution coprecipitated with barite and celestite; 95% coprecipitated with anglesite and less than 5% with gypsum under similar conditions. When jarosite was precipitated in the presence of thorium, a significant amount of thorium (78%) was incorporated in the precipitate.

Synthesis and sintering of UN-UO 2 fuel composites

DOE PAGES

Jaques, Brian J.; Watkins, Jennifer; Croteau, Joseph R.; ...

2015-06-17

In this study, the design and development of an economical, accident tolerant fuel (ATF) for use in the current light water reactor (LWR) fleet is highly desirable for the future of nuclear power. Uranium mononitride has been identified as an alternative fuel with higher uranium density and thermal conductivity when compared to the benchmark, UO 2, which could also provide significant economic benefits. However, UN by itself reacts with water at reactor operating temperatures. In order to reduce its reactivity, the addition of UO 2 to UN has been suggested. In order to avoid carbon impurities, UN was synthesized frommore » elemental uranium using a hydride-dehydride-nitride thermal synthesis route prior to mixing with up to 10 wt% UO 2 in a planetary ball mill. UN and UN – UO 2 composite pellets were sintered in Ar – (0–1 at%) N 2 to study the effects of nitrogen concentration on the evolved phases and microstructure. UN and UN-UO 2 composite pellets were also sintered in Ar – 100 ppm N 2 to assess the effects of temperature (1700–2000 °C) on the final grain morphology and phase concentration.« less

Geology of uranium in the Chadron area, Nebraska and South Dakota

USGS Publications Warehouse

Dunham, Robert Jacob

1961-01-01

The Chadron area covers 375 square miles about 25 miles southeast of the Black Hills. Recurrent mild tectonic activity and erosion on the Chadron arch, a compound anticlinal uplift of regional extent, exposed 1900 feet of Upper Cretaceous rocks, mostly marine shale containing pyrite and organic matter, and 600 feet of Oligocene and Miocene rocks, mostly terrestrial fine-grained sediment containing volcanic ash. Each Cretaceous formation truncated by the sub-Oligocene unconformity is stained yellow and red, leached, kaolinized, and otherwise altered to depths as great as 55 feet. The composition and profile of the altered material indicate lateritic soil; indirect evidence indicates Eocene(?) age. In a belt through the central part of the area, the Brule formation of Oligocene age is a sequence of bedded gypsum, clay, dolomite, and limestone more than 300 feet thick. Uranium in Cretaceous shale in 58 samples averages 0.002 percent, ten times the average for the earths crust. Association with pyrite and organic matter indicates low valency. The uranium probably is syngenetic or nearly so. Uranium in Eocene(?) soil in 43 samples averages 0.054 percent, ranging up to 1.12 percent. The upper part of the soil is depleted in uranium; enriched masses in the basal part of the soil consist of remnants of bedrock shale and are restricted to the highest reaches of the ancient oxidation-reduction interface. The uranium is probably in the from of a low-valent mineral, perhaps uraninite. Modern weathering of Cretaceous shale is capable of releasing as much as 0.780 ppm uranium to water. Eocene(?) weathering probably caused enrichment of the ancient soil through 1) leaching of Cretaceous shale, 2) downward migration of uranyl complex ions, and 3) reduction of hydrogen sulfide at the water table. Uranium minerals occur in the basal 25 feet of the gypsum facies of the Brule formation at the two localities where the gypsum is carbonaceous; 16 samples average 0.066 percent uranium and range up to 0.43 percent. Elsewhere uranium in dolomite and limestone in the basal 25 feet of the gypsum facies in 10 samples averages 0.007 percent, ranging up to 0.12 percent. Localization of the uranium at the base of the gypsum facies suggests downward moving waters; indirect evidence that the water from which the gypsum was deposited was highly alkaline suggests that the uranium was leached from volcanic ash in Oligocene time.

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 10-50times compared to control soil. The results of TOC (Total Organic Carbon content), CEC (Cation Exchange Capacity), T-N and T-P analysis of the soil with citric acid 25mM and 50mM were similar to control soil. Finally, the chelating agent was effective to use a citric acid 50mM .

Pharmacokinetic Evaluation of the Equivalency of Gavage, Dietary, and Drinking Water Exposure to Manganese in F344 Rats

PubMed Central

Foster, Melanie L.; Bartnikas, Thomas B.; Johnson, Laura C.; Herrera, Carolina; Pettiglio, Michael A.; Keene, Athena M.; Taylor, Michael D.; Dorman, David C.

2015-01-01

Concerns exist as to whether individuals may be at greater risk for neurotoxicity following increased manganese (Mn) oral intake. The goals of this study were to determine the equivalence of 3 methods of oral exposure and the rate (mg Mn/kg/day) of exposure. Adult male rats were allocated to control diet (10 ppm), high manganese diet (200 ppm), manganese-supplemented drinking water, and manganese gavage treatment groups. Animals in the drinking water and gavage groups were given the 10 ppm manganese diet and supplemented with manganese chloride (MnCl2) in drinking water or once-daily gavage to provide a daily manganese intake equivalent to that seen in the high-manganese diet group. No statistically significant difference in body weight gain or terminal body weights was seen. Rats were anesthetized following 7 and 61 exposure days, and samples of bile and blood were collected. Rats were then euthanized and striatum, olfactory bulb, frontal cortex, cerebellum, liver, spleen, and femur samples were collected for chemical analysis. Hematocrit was unaffected by manganese exposure. Liver and bile manganese concentrations were elevated in all treatment groups on day 61 (relative to controls). Increased cerebellum manganese concentrations were seen in animals from the high-manganese diet group (day 61, relative to controls). Increased (relative to all treatment groups) femur, striatum, cerebellum, frontal cortex, and olfactory bulb manganese concentrations were also seen following gavage suggesting that dose rate is an important factor in the pharmacokinetics of oral manganese. These data will be used to refine physiologically based pharmacokinetic models, extending their utility for manganese risk assessment by including multiple dietary exposures. PMID:25724921

The El Horror uranium anomaly in northeastern Sonora, Mexico: Constraints from geochemical and mineralogical approaches

NASA Astrophysics Data System (ADS)

Grijalva-Rodríguez, T.; Valencia-Moreno, M.; Calmus, T.; Del Rio-Salas, R.; Balcázar-García, M.

2017-12-01

This work reviews the characteristics of the El Horror uranium prospect in northeastern Sonora, Mexico. It was formerly detected by a radiometric anomaly after airborne gamma ray exploration carried out in the 70's by the Mexican government. As a promising site to contain important uranium resources, the El Horror was re-evaluated by CFE (Federal Electricity Commission) by in situ gamma ray surveys. The study also incorporates rock and stream sediment ICP-MS geochemistry, X-ray diffraction, X-ray fluorescence, Raman spectrometry and Scanning Electron Microscopy (SEM) to provide a better understanding of the radiometric anomaly. The results show that, instead of a single anomaly, it comprises at least five individual anomalies hosted in hydrothermally altered Laramide (80-40 Ma) andesitic volcanic rocks of the Tarahumara Formation. Concentrations for elemental uranium and uranium calculated from gamma ray surveys (i.e., equivalent uranium) are not spatially coincident within the anomaly, but, at least at some degree, they do so in specific sites. X-ray diffraction and Raman spectrometry revealed the presence of rutile/anatase, uvite, bukouvskyte and allanite as the more likely mineral phases to contain uranium. SEM studies revealed a process of iron-rich concretion formation, suggesting that uranium was initially incorporated to the system by adsorption, but was largely removed later during incorporation of Fe+3 ions. Stream sediment geochemistry reveals that the highest uranium concentrations are derived from the southern part of the Sierra La Madera batholith (∼63 Ma), and decrease toward the El Horror anomaly.

Preliminary investigations on the use of uranium silicide targets for fission Mo-99 production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cols, H.; Cristini, P.; Marques, R.

1997-08-01

The National Atomic Energy Commission (CNEA) of Argentine Republic owns and operates an installation for production of molybdenum-99 from fission products since 1985, and, since 1991, covers the whole national demand of this nuclide, carrying out a program of weekly productions, achieving an average activity of 13 terabecquerel per week. At present they are finishing an enlargement of the production plant that will allow an increase in the volume of production to about one hundred of terabecquerel. Irradiation targets are uranium/aluminium alloy with 90% enriched uranium with aluminium cladding. In view of international trends held at present for replacing highmore » enrichment uranium (HEU) for enrichment values lower than 20 % (LEU), since 1990 the authors are in contact with the RERTR program, beginning with tests to adapt their separation process to new irradiation target conditions. Uranium silicide (U{sub 3}Si{sub 2}) was chosen as the testing material, because it has an uranium mass per volume unit, so that it allows to reduce enrichment to a value of 20%. CNEA has the technology for manufacturing miniplates of uranium silicide for their purposes. In this way, equivalent amounts of Molybdenum-99 could be obtained with no substantial changes in target parameters and irradiation conditions established for the current process with Al/U alloy. This paper shows results achieved on the use of this new target.« less

Preliminary Investigation of the Dissolution Behavior, Cytocompatibility, Effects of Fibrinogen Conformation and Platelet Adhesion for Radiopaque Embolic Particles

PubMed Central

Kehoe, Sharon; Tremblay, Marie-Laurence; Coughlan, Aisling; Towler, Mark R.; Rainey, Jan K.; Abraham, Robert J.; Boyd, Daniel

2013-01-01

Experimental embolic particles based on a novel zinc-silicate glass system have been biologically evaluated for potential consideration in transcatheter arterial embolization procedures. In addition to controlling the cytotoxicity and haemocompatibility for such embolic particles, its glass structure may mediate specific responses via dissolution in the physiological environment. In a 120 h in-vitro dissolution study, ion release levels for silicon (Si4+), sodium (Na+), calcium (Ca2+), zinc (Zn2+), titanium (Ti4+), lanthanum (La3+), strontium (Sr2+), and magnesium (Mg2+), were found to range from 0.04 to 5.41 ppm, 0.27–2.28 ppm, 2.32–8.47 ppm, 0.16–0.20 ppm, 0.12–2.15 ppm, 0.16–0.49 ppm and 0.01–0.12 ppm, respectively for the series of glass compositions evaluated. Initial release of Zn2+ (1.93–10.40 ppm) was only evident after 120 h. All compositions showed levels of cell viabilities ranging from 61.31 ± 4.33% to 153.7 ± 1.25% at 25%–100% serial extract dilutions. The conformational state of fibrinogen, known to induce thrombi, indicated that no changes were induced with respect of the materials dissolution by-products. Furthermore, the best-in-class experimental composition showed equivalency to contour PVA in terms of inducing platelet adhesion. The data generated here provides requisite evidence to continue to in-vivo pre-clinical evaluation using the best-in-class experimental composition evaluated. PMID:24956083

Reactivity of uranium(iii) with H2E (E = S, Se, Te): synthesis of a series of mononuclear and dinuclear uranium(iv) hydrochalcogenido complexes.

PubMed

Franke, Sebastian M; Rosenzweig, Michael W; Heinemann, Frank W; Meyer, Karsten

2015-01-01

We report the syntheses, electronic properties, and molecular structures of a series of mono- and dinuclear uranium(iv) hydrochalcogenido complexes supported by the sterically demanding but very flexible, single N-anchored tris(aryloxide) ligand ( Ad ArO) 3 N) 3- . The mononuclear complexes [(( Ad ArO) 3 N)U(DME)(EH)] (E = S, Se, Te) can be obtained from the reaction of the uranium(iii) starting material [(( Ad ArO) 3 N)U III (DME)] in DME via reduction of H 2 E and the elimination of 0.5 equivalents of H 2 . The dinuclear complexes [{(( Ad ArO) 3 N)U} 2 (μ-EH) 2 ] can be obtained by dissolving their mononuclear counterparts in non-coordinating solvents such as benzene. In order to facilitate the work with the highly toxic gases, we created concentrated THF solutions that can be handled using simple glovebox techniques and can be stored at -35 °C for several weeks.

Hybrid vehicle system studies and optimized hydrogen engine design

NASA Astrophysics Data System (ADS)

Smith, J. R.; Aceves, S.

1995-04-01

We have done system studies of series hydrogen hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. We have evaluated the impact of various on-board storage options on fuel economy. Experiments in an available engine at the Sandia CRF demonstrated NO(x) emissions of 10 to 20 ppM at an equivalence ratio of 0.4, rising to about 500 ppm at 0.5 equivalence ratio using neat hydrogen. Hybrid simulation studies indicate that exhaust NO(x) concentrations must be less than 180 ppM to meet the 0.2 g/mile ULEV or Federal Tier II emissions regulations. LLNL has designed and fabricated a first generation optimized hydrogen engine head for use on an existing Onan engine. This head features 15:1 compression ratio, dual ignition, water cooling, two valves and open quiescent combustion chamber to minimize heat transfer losses. Initial testing shows promise of achieving an indicated efficiency of nearly 50% and emissions of less than 100 ppM NO(x). Hydrocarbons and CO are to be measured, but are expected to be very low since their only source is engine lubricating oil. A successful friction reduction program on the Onan engine should result in a brake thermal efficiency of about 42% compared to today's gasoline engines of 32%. Based on system studies requirements, the next generation engine will be about 2 liter displacement and is projected to achieve 46% brake thermal efficiency with outputs of 15 kW for cruise and 40 kW for hill climb.

Radioactivity and uranium content of the Sharon Springs member of the Pierre shale and associated rocks in western Kansas and eastern Colorado

USGS Publications Warehouse

Landis, Edwin R.

1955-01-01

As a part of the Geological Survey's program of investigating uranium-bearing carbonaceous rocks on behalf of the Division of Raw Materials of the U.S. Atomic Energy Commission, a reconnaissance of the Sharon Springs member of the Pierre shale in western Kansas and eastern Colorado was conducted during 1954. The Sharon Springs member of the Pierre shale and its lateral equivalents ranges from 155 to about 500 feet in thickness and generally contains about 0.001 percent uranium, but some beds contain larger amounts. A 6-foot thick shale bed in Cheyenne County, Colo., contains about 0.006 percent uranium, a 4 1/2-foot thick sequence of beds in Crowley County, Colo., is estimated to contain between 0.004 and 0.005 percent uranium, and a 3 1/2-foot thick sequence of beds in Kiowa County, Colo., contains about 0.004 percent uranium. At several outcrop localities, sequences of beds as much as 9 1/2 feet thick contain about 0.003 percent uranium. Data from wells indicate that the 4 1/2-foot thick sequence of beds in Crowley County, Colo., may have a lateral extent of at least 5 1/2 miles. A gamma-ray log of a well in Yuma County, Colo., indicates the presence of a sequence of beds 66 feet thick which contains 0.005 to 0.010 percent equivalent uranium. No definite pattern of areal distribution of radioactivity and uranium content in the Sharon Springs is indicated by available data. Lateral variation in uranium content of individual beds was not noted in outcrops, which seldom extend more than 150 feet, but subsurface data from gamma-ray logs of wells indicate that both the maximum radioactivity and the thickness of radioactive beds are variable within distances of a few miles. Vertical variation in radioactivity and uranium content of the more radioactive beds is usually abrupt, but in the rocks as a whole the range of uranium content is so small that large variations in content are absent. In most of the gamma-ray logs examined there is only part of the sequence of rocks comprising the Pierre shale and Niobrara formation that exhibits radioactivity in excess of the average radioactivity of the two formations. Comparison of features of gamma-ray logs of wells in north-eastern Colorado suggests that the most radioactive part referred to above is a laterally correlatable sequence of beds. The stratigraphic position of the radioactive unit relative to the Pierre shale-Niobrara formation contact in oil industry scout reports, as identified from electric logs and wells, is variable within short distances. This may indicate that some of the Pierre-Niobrara contacts picked from electric logs may not correspond to the boundary that would be selected by examination of the rocks themselves, or may indicate that there is a facies relationship between teh lowermost part of the Pierre shale and the uppermost part of the Niobrara formation.

Analysis of Tank 38H (HTF-38-15-119, 127) Surface, Subsurface and Tank 43H (HTF-43-15-116, 117 and 118) Surface, Feed Pump Suction and Jet Suction Subsurface Supernatant Samples in Support of Enrichment, Corrosion Control and Salt Batch Planning Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L.

Compositional feed limits have been established to ensure that a nuclear criticality event for the 2H and 3H Evaporators is not possible. The Enrichment Control Program (ECP) requires feed sampling to determine the equivalent enriched uranium content prior to transfer of waste other than recycle transfers (requires sampling to determine the equivalent enriched uranium at two locations in Tanks 38H and 43H every 26 weeks) The Corrosion Control Program (CCP) establishes concentration and temperature limits for key constituents and periodic sampling and analysis to confirm that waste supernate is within these limits. This report provides the results of analyses onmore » Tanks 38H and 43H surface and subsurface supernatant liquid samples in support of the ECP, the CCP, and the Salt Batch 10 Planning Program.« less

Nanoscale Zirconium-(oxyhydr)oxide in Contaminated Sediments From Hanford, WA - A New Host for Uranium

NASA Astrophysics Data System (ADS)

Stubbs, J. E.; Elbert, D. C.; Veblen, L. A.; Zachara, J. M.; Davis, J. A.; Veblen, D. R.

2008-12-01

Zirconium-, uranium-, and copper-bearing wastes have leached from former disposal ponds into vadose zone sediments in the 300 Area at the Department of Energy's Hanford Site. Zirconium is enriched in the shallow portion of the vadose zone, and we have discovered an amorphous Zr-(oxyhydr)oxide that contains 16% of the total uranium budget (84.24 ppm) in one of the shallow samples. We have characterized the oxide using electron microprobe analysis (EMPA), a focused ion beam (FIB) instrument, and transmission electron microscopy (TEM). It occurs in fine-grained coatings found on lithic and mineral fragments in these sediments. The oxide is intimately intergrown with the phyllosilicates and other minerals of the coatings, and in places can be seen coating individual, nano-sized phyllosilicate mineral grains. Electron energy-loss spectroscopy (EELS) shows that the Zr-(oxyhydr)oxide has a P:Zr atomic ratio around 0.2, suggesting it is either intergrown with minor amounts of a Zr-phosphate or has adsorbed a significant amount of phosphate. This material has adsorbed or incorporated a substantial amount of uranium. Thus, understanding its nature is critical to predicting the long-term fate of U in the Hanford vadose zone. While the low-temperature uptake of U by Zr-(oxhydr)oxides and phosphates has been studied for several decades in laboratory settings, to our knowledge ours is the first report of such uptake in the field.

NTP Toxicology and Carcinogenesis Studies of Primidone (CAS No. 125-33-7) in F344/N Rats and B6C3F1 Mice (Feed Studies).

PubMed

2000-09-01

Primidone is used alone or with other anticonvulsants in the control of grand mal, psychomotor, and focal epileptic seizures. It may control grand mal seizures refractory to other anticonvulsant therapy. Primidone was nominated by the National Cancer Institute for 2-year toxicology and carcinogenicity studies due to its human use as an anticonvulsant. Male and female F344/N rats and B6C3F1 mice received primidone (greater than 99% pure) in feed for 14 days, 14 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, and mouse bone marrow cells. 14-DAY STUDY IN RATS: Five male and five female rats were exposed to 0, 1,250, 2,500, 5,000, 10,000 or 20,000 ppm primidone (equivalent to average daily doses of approximately 120, 240, 500, 970, or 1,100 mg primidone/kg body weight to males and 120, 240, 500, or 900 mg/kg to females) in feed for 14 days. All 20,000 ppm females died before the end of the study as did one 10,000 ppm male and two 20,000 ppm males. The mean body weights of 10,000 ppm males and females and 20,000 ppm males were significantly less than those of the controls. Feed consumption by all exposed rats was generally similar to that by the controls. Males and females in the 10,000 and 20,000 ppm groups were observed to have eye discharge, ataxia, and abnormal posture and were thin and lethargic. 14-DAY STUDY IN MICE: Five male and five female mice were exposed to 0, 625, 1,250, 2,500, 5,000 or 10,000 ppm primidone (equivalent to average daily doses of approximately 100, 200, 400, or 800 mg/kg body weight to males and 100, 250, 500, or 900 mg/kg to females) in feed for 14 days. All mice in the 10,000 ppm groups and one male and one female mouse in the 5,000 ppm groups died on day 3 of the study. The mean body weights of mice in the 625, 1,250, 2,500, and 5,000 ppm groups were similar to those of the controls. Feed consumption by all exposed mice was generally similar to that by the controls. Males and females in the 10,000 ppm groups were observed to have abnormal posture, ataxia, and lethargy. 14-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were exposed to 0, 300, 600, 1,300, 2,500, or 5,000 ppm primidone (equivalent to average daily doses of approximately 20, 40, 100, 200, or 400 mg/kg) in feed for 14 weeks. All rats survived to the end of the study. The mean body weights of male and female rats in the 2,500 and 5,000 ppm groups were significantly less than those of the controls. Feed consumption by all exposed rats was generally similar to that by the controls. A minimal to mild exposure-related thrombocytosis occurred on day 22 and at week 14 in all exposed groups of male rats and in females in the 1,300 ppm or greater groups. A minimal decrease in hemoglobin concentration occurred in 2,500 and 5,000 ppm male and female rats on day 22 and at week 14. The incidences of centrilobular hepatocyte hypertrophy in male rats exposed to 600 ppm or greater and in female rats exposed to 1,300 ppm or greater were significantly greater than those in the controls. The severity of chronic nephropathy in male rats exposed to 1,300 ppm or greater increased with increasing exposure concentration. 14-WEEK STUDY IN MICE: Groups of 10 male and 10 female mice were exposed to 0, 300, 600, 1,300, 2,500, or 5,000 ppm primidone (equivalent to average daily doses of approximately 50, 100, 200, 400, or 1,000 mg/kg to males and 60, 120, 220, 440, or 1,100 mg/kg to females) in feed for 14 weeks. Three male and two female mice in the 5,000 ppm group died during week 1 of the study. The final mean body weights of all exposed groups were similar to those of the controls. Feed consumption by male mice in the 5,000 ppm group was slightly greater than that by the controls; this may have been due to feed spillage. Male and female mice in the 5,000 ppm groups were ataxic and lethargic. Compared to controls, the estrous cycle lengths of females exposed to 1,300, 2,500, or 5,000 ppm were significantly longer. The liver weights of male and female mice exposed to 600 po 600 ppm or greater were significantly greater than those of the controls. The incidences of centrilobular hepatocyte hypertrophy in all exposed males and in females exposed to 600 ppm or greater and the incidences of cytoplasmic alteration of the adrenal gland and hematopoietic cell proliferation of the spleen in 2,500 and 5,000 ppm males and in 5,000 ppm females were significantly greater than in the controls. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female F344/N rats were exposed to 0, 600, 1,300, or 2,500 ppm primidone (equivalent to average daily doses of approximately 25, 50, or 100 mg/kg) in feed for 2 years. Survival, Body Weights, and Feed Consumption Survival of the 1,300 and 2,500 ppm males was sig nificantly less than that of the controls. The mean body weights of males and females in the 2,500 ppm groups were less than those of the controls, beginning at week 29 for males and week 17 for females; the mean body weights of 1,300 ppm males and females were less than those of the controls during the second year of the study. Feed consumption by all exposed groups of rats was generally similar to that by the controls. Pathology Findings Male rats exposed to primidone had increased inci dences of thyroid gland follicular cell neoplasms (adenoma and/or carcinoma). All exposed groups of male rats had follicular cell adenomas or carcinomas (combined) at incidences above the historical control range, with the highest incidence in the 1,300 ppm group. Hepatocyte cytoplasmic vacuolation and centrilobular hypertrophy were associated with primidone exposure in male and female rats. These changes were more severe in females than in males and the incidences in all exposed groups of females were significantly greater than those in the controls. Females in the 2,500 ppm group had an increased incidence of hepatocellular eosinophilic foci. In 2,500 ppm males, the incidence of renal tubule hyperplasia was greater than that in the controls in the standard evaluation. Additional hyperplasias were found in the extended evaluation, and the incidences in exposed groups of males were significantly greater than that in the controls. In the extended evaluation, the incidence of renal tubule adenoma in 2,500 ppm males was significantly increased. The incidence of adenoma or carcinoma (combined) in 2,500 ppm males in the combined standard and extended evaluations were marginally increased over those in the controls. Male rats had an exposure-related increase in the severity of chronic nephropathy, which probably accounted for the reduced survival in the 1,300 and 2,500 ppm groups. The incidences of kidney cysts were increased in 1,300 and 2,500 ppm males. Hyperparathyroidism, secondary to the loss of renal function, was present in many exposed male rats. The incidences of parathyroid gland hyperplasia in all groups of exposed males were significantly greater than that in the controls. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were exposed to dietary levels of 0, 300, 600, or 1,300 ppm primidone (equivalent to average daily doses of approximately 30, 65, or 150 mg/kg to males and 25, 50, or 100 mg/kg to females) in feed for 2 years. Survival, Body Weights, Feed Consumption, and Clinical Findings Survival of the 1,300 ppm males was significantly less than that of the controls. During the second year of the study, the mean body weights of 1,300 ppm male and female mice were less than those of the controls. The final mean body weights of 600 ppm males and females were less than those of the controls. Feed consumption by all exposed groups of mice was similar to that by the controls. During the latter part of the study, a treatment-related increase in the number of animals with swelling of the abdominal area was observed; necropsy revealed that the swelling was due to liver nodules/masses. Pathology Findings The liver was a target organ in both male and female mice. The incidences and multiplicities of hepatocellular neoplasms (hepatocellular adenoma, hepatocellular carcinoma, and hepatoblastoma) in all exposed groups of males and females (except hepatoblastoma in females) were significantly greater than those in the controls. The incidences of hepatocellular adenoma or carcinoma (combined) and hepatocellular adenoma, hepatocellular carcinoma, or hepatoblastoma (combined) in all exposed groups exceeded the historical control ranges in 2-year NTP studies. The incidences of centrilobular hepatocyte hypertrophy were increased in exposed groups of males and females, and the severities increased with increasing exposure concentration. The incidences of cytoplasmic vacuolization were increased in all exposed groups of females and in 300 ppm males. Incidences of eosinophilic focus in all exposed groups of females were significantly greater than those in the controls. Proliferative changes occurred in the thyroid gland in an exposure-related manner in male and female mice. Incidences of follicular cell hyperplasia were increased in all exposed groups of males and in 600 and 1,300 ppm females, but incidences of follicular cell adenomas were increased only in male mice. GENETIC TOXICOLOGY: Primidone was mutagenic in Salmonella typhimurium strain TA1535 in the absence of S9 activation only; no mutagenicity was detected in strain TA98, TA100, or TA1537, with or without S9. Primidone did not induce sister chromatid exchanges or chromosomal aberrations in cultured Chinese hamster ovary cells, with or without S9. The single in vivo study with primidone, a mouse bone marrow micronucleus test, also gave negative results. CONCLUSIONS: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of primidone in male F344/N rats based on a marginal increase in thyroid gland follicular cell neoplasms, primarily adenomas, and a marginal increase in renal tubule neoplasms. There was no evidence of carcinogenic activity of primidone in female F344/N rats exposed to 600, 1,300, or 2,500 ppm. There was clear evidence of carcinogenic activity of primidone in male B6C3F1 mice based on the increased incidences of hepatocellular neoplasms, and the increased incidence of thyroid gland follicular cell adenomas was also considered to be chemical related. There was clear evidence of carcinogenic activity of primidone in female B6C3F1 mice based on the increased incidences of hepatocellular neoplasms. Exposure of rats to primidone resulted in increased incidences of hepatocyte cytoplasmic vacuolization and centrilobular hypertrophy in males and females and eosinophilic foci in females. The increased severity of nephropathy and increased incidence of renal tubule hyperplasia in male rats were related to primidone exposure. Exposure of male mice to primidone resulted in hepatocyte centrilobular hypertrophy and thyroid gland follicular cell hyperplasia. Exposure of female mice to primidone resulted in hepatocyte centrilobular hypertrophy and cytoplasmic vacuolization, eosinophilic focus, and thyroid gland follicular cell hyperplasia. Synonyms: 5-Aethyl-5-phenyl-hexahydropyrimidin-4,6-dion; 2-deoxyphenobarbital; 2-desoxyphenobarbital; desoxyphenobarbitone; 5-ethyldihydro-5-phenyl-4,6 (1H,5H)-pyrimidinedione; 5-ethylhexahydro-4,6-dioxo-5-phenylphrimidine; 5-ethylhexahydro-5-phenylpyrimidine-4,6-dione; 5-ethyl-5-phenylhexahydropyrimidine-4,6-dione Trade names: Cyral; Hexadiona; Hexamidine; Lepimidin; Lepsiral; Majsolin; Midone; Milepsin; Misodine; Misolyne; Mizodin; Mizolin; Mylepsin; Mylepsinum; Mysedon; Mysoline; Prilepsin; Primacione; Primaclone; Primacone; Primakton; Primadon; Prysoline; Pyrimidone; ROE 101; Sertan

40 CFR 761.274 - Reporting PCB concentrations in samples.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN... concentrations for non-liquid PCBs on a dry weight basis as micrograms of PCBs per gram of sample (ppm by weight... quotient by the total number of micrograms of PCBs on the surface to obtain the equivalent measurement of...

40 CFR 761.274 - Reporting PCB concentrations in samples.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN... concentrations for non-liquid PCBs on a dry weight basis as micrograms of PCBs per gram of sample (ppm by weight... quotient by the total number of micrograms of PCBs on the surface to obtain the equivalent measurement of...

High tocopherol and triacylglycerol contents in Pinus pinea L. seeds.

PubMed

Nasri, Nizar; Tlili, Nizar; Ben Ammar, Kamel; Khaldi, Abdelhamid; Fady, Bruno; Triki, Saida

2009-01-01

Oleaginous seeds are among the functional foods most recognized for their tocopherols and triacylglycerols because of their role in lipid metabolism. In this paper, the tocopherol and triacylglycerol contents in seeds of several Pinus pinea L. populations around the Mediterranean Basin were investigated. Lipids were extracted from fully ripen seeds with petroleum ether. The tocopherol (alpha-tocopherol, gamma-tocopherol, and delta-tocopherol) contents were, respectively, 15.34+/-3.75 ppm, 1,681.75+/-404.03 ppm and 41.87+/-9.79 ppm. Lipids (mainly triacylglycerols) in P. pinea seeds averaged 48% on a dry weight basis. Triacylglycerols with an equivalent carbon number of 44 (32.27%) and of 46 (30.91%) were dominant. The major triacylglycerol was LLO (24.06%). Tocopherols and triacylglycerols were present at remarkably high levels, thus making P. pinea oil a valuable source of antioxidants and unsaturated fatty acids with varying levels across the geographical range of P. pinea.

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

NASA Astrophysics Data System (ADS)

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

2014-02-01

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) & 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) &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 232Th 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.

Progress in understanding uranium(IV) speciation and dynamics in biologically reduced sediments: Research at molecular to centimeter scales by the SLAC SFA program

NASA Astrophysics Data System (ADS)

Bargar, J.; Williams, K. H.; Campbell, K. M.; Stubbs, J. E.; Suvorova, E.; Lezama-Pacheco, J. S.; Alessi, D.; Stylo, M.; Handley, K. M.; Bernier-Latmani, R.; Cerrato, J.; Davis, J. A.; Fox, P. M.; Giammar, D.; Long, P. E.

2011-12-01

The chemical and physical forms of U(IV) in reduced sediments, as well as the biogeochemical processes by which they form and transform, profoundly influence the stability of reduced U(IV) species and the behavior of uranium in biostimulated aquifers. Obtaining such information in field sediments is important because biogeochemical field conditions and their time dependence are difficult to replicate in the laboratory. The majority of contaminated aquifers in which bioremediation is of potential interest, including the Old Rifle, CO IFRC site, exhibit relatively low uranium sediment concentrations, i.e., < 10 ppm, presenting a formidable challenge to the use of spectroscopy and microscopy techniques that typically require 10-fold or higher uranium loadings. We have developed an in-situ column technique to study U(IV) species and evolving microbial communities in the Old Rifle aquifer and to correlate them with changes in trace and major ion groundwater composition during biostimulation treatments. Sediments were examined using x-ray and electron microscopy, x-ray absorption spectroscopy (XAS), and chemical extractions. XAS analysis showed that U(IV) occurred predominantly or exclusively as monomeric U(IV) complexes coordinated to oxo (or similar N/C) neighbors, and is associated with biomass or Fe sulfides. Even in the latter case, U(IV) was not coordinated directly to S neighbors. Sediment-hosted monomeric U(IV) complexes were found to partially transform into uraninite in the aquifer over a subsequent 12 month period. This work establishes the importance of monomeric U(IV) complexes in subsurface sediments at the Old Rifle site and provides a conceptual framework in which previously observed U(IV) reduction products can be related. These experiments also establish that U(IV) species are dynamic in aquifers and can undergo non-oxidative transformation reactions. These new results have important implications for uranium reactive transport models, long-term assessment of remediation technologies, and understanding natural uranium reduction in aquifers.

Petrography and geochemistry of granitoids from the Samphire Pluton, South Australia: Implications for uranium mineralisation in overlying sediments

NASA Astrophysics Data System (ADS)

Domnick, Urs; Cook, Nigel J.; Bluck, Russel; Brown, Callan; Ciobanu, Cristiana L.

2018-02-01

The Blackbush uranium deposit (JORC Inferred Resource: 12,580 tonnes U), located on the north-eastern Eyre Peninsula, is currently the only sediment-hosted U deposit investigated in detail in the Gawler Craton. Uranium is hosted within Eocene sandstone of the Kanaka Beds, overlying Mesoproterozoic granites of the Samphire pluton, affiliated with the Hiltaba Intrusive Suite ( 1.6 Ga). These are considered the most probable source rocks for uranium mineralisation. By constraining the petrography and mineralogy of the granites, insights into the post-emplacement evolution can be gained, which may provide an exploration indicator for other sediment-hosted uranium systems. Three geochemically distinct granite types were identified in the Samphire Pluton and correspond to domains interpreted from geophysical data. All granites show complex alteration overprints and textures with increasing intensity closer to the deposit, as well as crosscutting veining. Alkali feldspar has been replaced by porous K-feldspar and albite, and plagioclase is overprinted by an assemblage of porous albite + sericite ± calc-silicates (prehnite, pumpellyite and epidote). This style of feldspar alteration is regionally widespread and known from Hiltaba-aged granites associated with iron-oxide copper-gold mineralisation at Olympic Dam and in the Moonta-Wallaroo region. In two granite types biotite is replaced by calcic garnet. Calc-silicates are indicative of Ca-metasomatism, sourced from the anorthite component of altered plagioclase. Minor clay alteration of feldspars is present in all samples. Mineral assemblages in veins include quartz + hematite, hematite + coffinite, fluorite + quartz, and clay minerals. Minor chlorite and sericite are found in all vein types. All granite types are anomalously rich in U (concentrations between 10 and 81 ppm). Highly variable Th/U ratios, as well as hydrothermal U minerals (mostly coffinite) in granites and veins, are clear evidence for U mobility. Uranium may have been preconcentrated in veins in the upper parts of the pluton, and was subsequently leached after deposition of the sediment.

Estimates of radiological risk from depleted uranium weapons in war scenarios.

PubMed

Durante, Marco; Pugliese, Mariagabriella

2002-01-01

Several weapons used during the recent conflict in Yugoslavia contain depleted uranium, including missiles and armor-piercing incendiary rounds. Health concern is related to the use of these weapons, because of the heavy-metal toxicity and radioactivity of uranium. Although chemical toxicity is considered the more important source of health risk related to uranium, radiation exposure has been allegedly related to cancers among veterans of the Balkan conflict, and uranium munitions are a possible source of contamination in the environment. Actual measurements of radioactive contamination are needed to assess the risk. In this paper, a computer simulation is proposed to estimate radiological risk related to different exposure scenarios. Dose caused by inhalation of radioactive aerosols and ground contamination induced by Tomahawk missile impact are simulated using a Gaussian plume model (HOTSPOT code). Environmental contamination and committed dose to the population resident in contaminated areas are predicted by a food-web model (RESRAD code). Small values of committed effective dose equivalent appear to be associated with missile impacts (50-y CEDE < 5 mSv), or population exposure by water-independent pathways (50-y CEDE < 80 mSv). The greatest hazard is related to the water contamination in conditions of effective leaching of uranium in the groundwater (50-y CEDE < 400 mSv). Even in this worst case scenario, the chemical toxicity largely predominates over radiological risk. These computer simulations suggest that little radiological risk is associated to the use of depleted uranium weapons.

Exam Question Exchange.

ERIC Educational Resources Information Center

Alexander, John J., Ed.

1978-01-01

Two exam questions are presented. One suitable for advanced undergraduate or beginning graduate courses in organic chemistry, is on equivalent expressions for the description of several pericyclic reactions. The second, for general chemistry students, asks for an estimation of the rate of decay of a million-year-old Uranium-238 sample. (BB)

Spectrophotometric determination of pyrrole-like substances in urine of rat and man: an assay for the evaluation of 2,5-hexanedione formed from n-hexane.

PubMed

Kessler, W; Heilmaier, H; Kreuzer, P; Shen, J H; Filser, M; Filser, J G

1990-01-01

Male Wistar rats exposed to atmospheric n-hexane excreted in their urine substances which gave rise to absorption spectra like those of pyrroles after the reaction with Ehrlich's reagent. A simple spectrophotometric assay was developed to determine these "pyrrole-like substances" in urine. Their excretion kinetics were evaluated by exposing rats for 8 h to atmospheric n-hexane concentrations between 50 and 3000 ppm. The dose-response curve revealed saturation kinetics according to Michaelis-Menten, Vmax being 1.12 [delta E526.ml urine/8 h n-hexane exposure] and "Km", the atmospheric n-hexane concentration at Vmax/2, being 250 ppm. The excretion of pyrrole-like substances closely correlated with that of 2,5-hexanedione measured by Fedtke and Bolt (1987). Pyrrole-like substances were also found in the urine of a male volunteer. When exposing the person for 3 h to atmospheric n-hexane at a concentration of 146 ppm (equivalent to 55 ppm/8 h) the excreted amount was twice the background value. Due to the sensitivity of this assay it is possible to determine pyrrole-like substances in urine according to the present German MAK or US TLV conditions for n-hexane (50 ppm/8 h).

Uranium (U)-Tolerant Bacterial Diversity from U Ore Deposit of Domiasiat in North-East India and Its Prospective Utilisation in Bioremediation

PubMed Central

Kumar, Rakshak; Nongkhlaw, Macmillan; Acharya, Celin; Joshi, Santa Ram

2013-01-01

Uranium (U)-tolerant aerobic chemo-heterotrophic bacteria were isolated from the sub-surface soils of U-rich deposits in Domiasiat, North East India. The bacterial community explored at molecular level by amplified ribosomal DNA restriction analysis (ARDRA) resulted in 51 distinct phylotypes. Bacterial community assemblages at the U mining site with the concentration of U ranging from 20 to 100 ppm, were found to be most diverse. Representative bacteria analysed by 16S rRNA gene sequencing were affiliated to Firmicutes (51%), Gammaproteobacteria (26%), Actinobacteria (11%), Bacteroidetes (10%) and Betaproteobacteria (2%). Representative strains removed more than 90% and 53% of U from 100 μM and 2 mM uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure and the activity was retained until 24 h. Overall, 76% of characterized isolates possessed phosphatase enzyme and 53% had PIB-type ATPase genes. This study generated baseline information on the diverse indigenous U-tolerant bacteria which could serve as an indicator to estimate the environmental impact expected to be caused by mining in the future. Also, these natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments. PMID:23080407

Spallation studies on shock loaded uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonks, D.L.; Hixson, R.; Gustavsen, R.L.

1997-12-31

Uranium samples at two different purity levels were used for spall strength measurements at three different stress levels. A 50 mm single-stage gas-gun was used to produce planar impact conditions using Z-cut quartz impactors. Samples of depleted uranium were taken from very high purity material and from material that had 300 ppm of carbon added. A pair of shots was done for each impact strength, one member of the pair with VISAR diagnostics and the second with soft recovery for metallographical examination. A series of increasing final stress states were chosen to effectively freeze the microstructural damage at three placesmore » in the development to full spall separation. This allowed determination of the dependence of spall mechanisms on stress level and sample purity. This report will discuss both the results of the metallurgical examination of soft recovered samples and the modeling of the free surface VISAR data. The micrographs taken from the recovered samples show brittle cracking as the spallation failure mechanism. Deformation induced twins are plentiful and obviously play a role in the spallation process. The twins are produced in the initial shock loading and, so, are present already before the fracture process begins. The 1 d characteristics code CHARADE has been used to model the free surface VISAR data.« less

Geology of the Midnite uranium mine area, Washington: maps, description, and interpretation

USGS Publications Warehouse

Nash, J. Thomas

1977-01-01

Bedrock geology of about 12 km2 near the Midnite mine has been mapped at the surface, in mine exposures, and from drilling, at scales from 1:600 to 1:12,000 and is presented here at 1:12,000 to provide description of the setting of uranium deposits. Oldest rocks in the area are metapelitic and metacarbonate rocks of the Precambrian (Y) Togo Formation. The chief host for uranium deposits is graphitic and pyritic mica phyllite and muscovite schist. Ore also occurs in calc-silicate hornfels and marble at the western edge of a calcareous section about 1,150 m thick. Calcareous rocks of the Togo are probably older than the pelitic as they are interpreted to be near the axis of a broad anticline. The composition and structural position of the calcareous unit suggests correlation with less metamorphosed carbonate-bearing rocks of the Lower Wallace Formation, Belt Supergroup, about 200 km to the east. Basic sills intrusive into the Togo have been metamorphosed to amphibolite. Unmetamorphosed rocks in the mine area are Cretaceous(?) and Eocene igneous rocks. Porphyritic quartz monzonite of Cretaceous age, part of the Loon Lake batholith, is exposed over one third of the mine area. It underlies the roof pendant of Precambrian rocks in which the Midnite mine occurs at depths of generally less than 300 m. The pluton is a two-mica granite and exhibits pegmatitic and aplitic textural features indicative of water saturation and pressure quenching. Eocene intrusive and extrusive rocks in the area provide evidence that the Eocene surface was only a short distance above the present uranium deposits. Speculative hypotheses are presented for penesyngenetic, hydrothermal, and supergene modes of uranium emplacement. The Precambrian Stratigraphy, similar in age and pre-metamorphic lithology to that of rocks hosting large uranium deposits in Saskatchewan and Northern Territory, Australia, suggests the possibility of uranium accumulation along with diagenetic pyrite in carbonaceous muds in a marine shelf environment. This hypothesis is not favored by the author because there is no evidence for stratabound uranium such as high regional radioactivity in the Togo. A hydrothermal mode of uranium emplacement is supported by the close apparent ages of mineralization and plutonism, and by petrology of the pluton. I speculate that uranium may have become enriched in postmagmatic fluids at the top of the pluton, possibly by hydrothermal leaching of soluble uranium associated with magnetite, and diffused outward into metasedimentary wall rocks to create an aureole about 100 m thick containing about 100 ppm uranium. Chemistry of the hydrothermal process is not understood, but uranium does not appear to have been transported by an oxidizing fluid, and the fluid did not produce veining and alteration comparable to that of base-metal sulfide deposits. Uranium in the low-grade protore is believed to have been redistributed into permeable zones in the Tertiary to create ore grades. Geologic and isotopic ages of uranium mineralization, and the small volume of porphyritic quartz monzonite available for leaching, are not supportive of supergene emplacement of uranium.

The interaction between nitride uranium and stainless steel

NASA Astrophysics Data System (ADS)

Shornikov, D. P.; Nikitin, S. N.; Tarasov, B. A.; Baranov, V. G.; Yurlova, M. S.

2016-04-01

Uranium nitride is most popular nuclear fuel for Fast Breeder Reactor New Generation. In-pile experiments at reactor BOR-60 was shown an interaction between nitride fuel and stainless steel in the range of 8-11% burn up (HA). In order to investigate this interaction has been done diffusion tests of 200 h and has been shown that the reaction occurs in the temperature range 1000-1100 ° C. UN interacted with steel in case of high pollution oxygen (1000-2000 ppm). Also has been shown to increase interaction UN with EP-823 steel in the presence of cesium. In this case the interaction layer had a thickness about 2-3 μm. Has been shown minimal interaction with new ODS steel EP-450. The interaction layer had a thickness less then 2 μm. Did not reveal the influence of tellurium and iodine increased interaction. It was show compatibility at 1000 °C between UN and EP-450 ODS steel, chrome steel, alloying aluminium and silicium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, I-Ting; Sessler, Jonathan L.; Gambhir, Sanjiv Sam

Chemical tools that can report radioactive isotopes would be of interest to the defense community. Here in this paper we report –250 nm polymeric nanoparticles containing porphyrinoid macrocycles with and without pre-complexed depleted uranium and demonstrate that the latter species may be detected easily and with high sensitivity via photoacoustic imaging. The porphyrinoid macrocycles used in the present study are non-aromatic in the absence of the uranyl cation, but aromatic after cation complexation. We solubilized both the freebase and metalated forms of the macrocycles in poly(lactic-co-glycolic acid) and found a peak in the photoacoustic spectrum at 910 nm excitation inmore » the case of the uranyl complex. The signal was stable for at least 15 minutes and allowed detection of uranium concentrations down to 6.2 ppb (5.7 nM) in vitro and 0.57 ppm (19 fCi; 0.52 μM) in vivo. Furthermore, to the best of our knowledge, this is the first report of a nanoparticle that detects an actinide cation via photoacoustic imaging.« less

Uranium reduction and resistance to reoxidation under iron-reducing and sulfate-reducing conditions.

PubMed

Boonchayaanant, Benjaporn; Nayak, Dipti; Du, Xin; Criddle, Craig S

2009-10-01

Oxidation and mobilization of microbially-generated U(IV) is of great concern for in situ uranium bioremediation. This study investigated the reoxidation of uranium by oxygen and nitrate in a sulfate-reducing enrichment and an iron-reducing enrichment derived from sediment and groundwater from the Field Research Center in Oak Ridge, Tennessee. Both enrichments were capable of reducing U(VI) rapidly. 16S rRNA gene clone libraries of the two enrichments revealed that Desulfovibrio spp. are dominant in the sulfate-reducing enrichment, and Clostridium spp. are dominant in the iron-reducing enrichment. In both the sulfate-reducing enrichment and the iron-reducing enrichment, oxygen reoxidized the previously reduced uranium but to a lesser extent in the iron-reducing enrichment. Moreover, in the iron-reducing enrichment, the reoxidized U(VI) was eventually re-reduced to its previous level. In both, the sulfate-reducing enrichment and the iron-reducing enrichment, uranium reoxidation did not occur in the presence of nitrate. The results indicate that the Clostridium-dominated iron-reducing communities created conditions that were more favorable for uranium stability with respect to reoxidation despite the fact that fewer electron equivalents were added to these systems. The likely reason is that more of the added electrons are present in a form that can reduce oxygen to water and U(VI) back to U(IV).

40 CFR 61.21 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dose equivalent and the definition of reference man are outlined in the International Commission on... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Definitions. 61.21 Section 61.21... Underground Uranium Mines § 61.21 Definitions. As used in this subpart, all terms not defined here have the...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iseki, Tadahiro; Inaba, Makoto; Takahashi, Naoki

During the second and third steps of Active Test at Rokkasho Reprocessing Plant (RRP), the performances of the Separation Facility have been checked; (A) diluent washing efficiency, (B) plutonium stripping efficiency, (C) decontamination factor of fission products and (D) plutonium and uranium leakage into raffinate and spent solvent. Test results were equivalent to or better than expected. (authors)

40 CFR 190.02 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... sup-port -of these operations, and the reuse of -recovered non-uranium special nu-clear and by-product...) Site means the area contained within the boundary of a location under the control of persons possessing... second. (One millicurie (mCi)=0.001 Ci.) (h) Dose equivalent means the product of absorbed dose and...

40 CFR 190.02 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... sup-port -of these operations, and the reuse of -recovered non-uranium special nu-clear and by-product...) Site means the area contained within the boundary of a location under the control of persons possessing... second. (One millicurie (mCi)=0.001 Ci.) (h) Dose equivalent means the product of absorbed dose and...

40 CFR 190.02 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... sup-port -of these operations, and the reuse of -recovered non-uranium special nu-clear and by-product...) Site means the area contained within the boundary of a location under the control of persons possessing... second. (One millicurie (mCi)=0.001 Ci.) (h) Dose equivalent means the product of absorbed dose and...

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

PubMed

Döppner, T; Callahan, D A; Hurricane, O A; Hinkel, D E; Ma, T; Park, H-S; Berzak Hopkins, L F; Casey, D T; Celliers, P; Dewald, E L; Dittrich, T R; Haan, S W; Kritcher, A L; MacPhee, A; Le Pape, S; Pak, A; Patel, P K; Springer, P T; Salmonson, J D; Tommasini, R; Benedetti, L R; Bond, E; Bradley, D K; Caggiano, J; Church, J; Dixit, S; Edgell, D; Edwards, M J; Fittinghoff, D N; Frenje, J; Gatu Johnson, M; Grim, G; Hatarik, R; Havre, M; Herrmann, H; Izumi, N; Khan, S F; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Merrill, F E; Moody, J; Moore, A S; Nikroo, A; Ralph, J E; Remington, B A; Robey, H F; Sayre, D; Schneider, M; Streckert, H; Town, R; Turnbull, D; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

2015-07-31

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Döppner, T.; Callahan, D. A.; Hurricane, O. A.

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility

DOE PAGES

Döppner, T.; Callahan, D. A.; Hurricane, O. A.; ...

2015-07-28

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a “highfoot” laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shapemore » closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10 16 neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.« less

Inert matrix fuel in dispersion type fuel elements

NASA Astrophysics Data System (ADS)

Savchenko, A. M.; Vatulin, A. V.; Morozov, A. V.; Sirotin, V. L.; Dobrikova, I. V.; Kulakov, G. V.; Ershov, S. A.; Kostomarov, V. P.; Stelyuk, Y. I.

2006-06-01

The advantages of using inert matrix fuel (IMF) as a dispersion fuel in an aluminium alloy matrix are considered, in particular, low temperatures in the fuel centre, achievable high burn-ups, serviceability in transients and an environmentally friendly process of fuel rod fabrication. Two main versions of IMF are under development at A.A. Bochvar Institute, i.e. heterogeneous or isolated distribution of plutonium. The out-of-pile results on IMF loaded with uranium dioxide as plutonium simulator are presented. Fuel elements with uranium dioxide composition fabricated at A.A. Bochvar Institute are currently under MIR tests (RIAR, Dimitrovgrad). The fuel elements reached a burn-up of 88 MW d kg-1 (equivalent to the burn up of the standard uranium dioxide pelletized fuel) without loss of leak-tightness of the cladding. The feasibility of fabricating IMF of these particular types with plutonium dioxide is considered with a view to in-pile irradiation.

Chlorosilane acute inhalation toxicity and development of an LC50 prediction model.

PubMed

Jean, Paul A; Gallavan, Robert H; Kolesar, Gary B; Siddiqui, Waheed H; Oxley, Jon A; Meeks, Robert G

2006-07-01

The acute inhalation toxicity of 10 chlorosilanes was investigated in Fischer 344 rats using a 1-h whole-body vapor inhalation exposure and a 14-day recovery period. The median lethal concentration (LC50(1)) for each material was calculated from the nominal exposure concentrations and mortality. Experimentally derived LC50(1) values for monochlorosilanes (4257-4478 ppm) were greater than those for dichlorosilanes (1785-2092 ppm), which were greater than those for trichlorosilanes (1257-1611 ppm). Apparent was a strong structure-activity relationship (r2 = .97) between chlorine content and LC50(1) value. Estimated LC50(1) values for mono-, di-, and trichlorosilanes were determined to be 3262, 1639, and 1066 ppm, respectively, utilizing this relationship and the lower limit of the 95% prediction interval. The LC50(1) values determined in this series of studies were greater than that reported for hydrogen chloride (3124 ppm), when expressed on a chlorine equivalence basis (3570-5248 ppm), demonstrating that the acute toxicity of these chlorosilanes is similar to or less than that for hydrogen chloride. The good correlation between chlorine content and LC50(1) provides a sound basis for estimation of LC50(1) for chlorosilanes not already evaluated. The use of structure-activity relationships is consistent with the chemical industry and federal agency initiatives to reduce, refine, and/or replace the use of animals in testing without compromising the quality of health and safety assessments.

40 CFR 86.1314-94 - Analytical gases.

Code of Federal Regulations, 2010 CFR

2010-07-01

... CO2. respectively, using nitrogen as the diluent. (b) Gases for the hydrocarbon analyzer shall be: (1... named as NOX with a maximum NO2 concentration of five percent of the nominal value using nitrogen as the... the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon response. 98 to...

40 CFR 86.1314-94 - Analytical gases.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CO2. respectively, using nitrogen as the diluent. (b) Gases for the hydrocarbon analyzer shall be: (1... named as NOX with a maximum NO2 concentration of five percent of the nominal value using nitrogen as the... the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon response. 98 to...

40 CFR 86.1314-94 - Analytical gases.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CO2. respectively, using nitrogen as the diluent. (b) Gases for the hydrocarbon analyzer shall be: (1... named as NOX with a maximum NO2 concentration of five percent of the nominal value using nitrogen as the... the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon response. 98 to...

40 CFR 86.1314-94 - Analytical gases.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CO2. respectively, using nitrogen as the diluent. (b) Gases for the hydrocarbon analyzer shall be: (1... named as NOX with a maximum NO2 concentration of five percent of the nominal value using nitrogen as the... the balance being helium. The mixture shall contain less than 1 ppm equivalent carbon response. 98 to...

Comparison of the Effect of Curing Ingredients Derived from Purified and Natural Sources on Inhibition of Clostridium perfringens Outgrowth during Cooling of Deli-Style Turkey Breast.

PubMed

King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

2015-08-01

The antimicrobial impact of purified and natural sources of both nitrite and ascorbate were evaluated against Clostridium perfringens during the postthermal processing cooling period of deli-style turkey breast. The objective of phase I was to assess comparable concentrations of nitrite (0 or 100 ppm) and ascorbate (0 or 547 ppm) from both purified and natural sources. Phase II was conducted to investigate concentrations of nitrite (50, 75, or 100 ppm) from cultured celery juice powder and ascorbate (0, 250, or 500 ppm) from cherry powder to simulate alternative curing formulations. Ground turkey breast (75% moisture, 1.2% salt, pH 6.2) treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in 10 additional hours. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar; experiments were replicated three times. In phase I, uncured, purified nitrite, and natural nitrite treatments without ascorbate had 5.3-, 4.2-, and 4.4-log increases in C. perfringens, respectively, at 15 h, but <1-log increase was observed at the end of chilling in treatments containing 100 ppm of nitrite and 547 ppm of ascorbate from either source. In phase II, 0, 50, 75, and 100 ppm of nitrite and 50 ppm of nitrite plus 250 ppm of ascorbate supported 4.5-, 3.9-, 3.5-, 2.2-, and 1.5-log increases in C. perfringens, respectively. In contrast, <1-log increase was observed after 15 h in the remaining phase II treatments supplemented with 50 ppm of nitrite and 500 ppm of ascorbate or ≥75 ppm of nitrite and ≥250 ppm of ascorbate. These results confirm that equivalent concentrations of nitrite, regardless of the source, provide similar inhibition of C. perfringens during chilling and that ascorbate enhances the antimicrobial effect of nitrite on C. perfringens at concentrations commonly used in alternative cured meats.

The Early Anthropogenic Hypothesis: Top-Down and Bottom-up Evidence

NASA Astrophysics Data System (ADS)

Ruddiman, W. F.

2014-12-01

Two complementary lines of evidence support the early anthropogenic hypothesis. Top-down evidence comes from comparing Holocene greenhouse-gas trends with those during equivalent intervals of previous interglaciations. The increases in CO2 and CH4 during the late Holocene are anomalous compared to the decreasing trends in a stacked average of previous interglaciations, thereby supporting an anthropogenic origin. During interglacial stage 19, the closest Holocene insolation analog, CO2 fell to 245 ppm by the time equivalent to the present, in contrast to the observed pre-industrial rise to 280-285 ppm. The 245-ppm level measured in stage 19 falls at the top of the natural range predicted by the original anthropogenic hypothesis of Ruddiman (2003). Bottom-up evidence comes from a growing list of archeological and other compilations showing major early anthropogenic transformations of Earth's surface. Key examples include: efforts by Dorian Fuller and colleagues mapping the spread of irrigated rice agriculture across southern Asia and its effects on CH4 emissions prior to the industrial era; an additional effort by Fuller showing the spread of methane-emitting domesticated livestock across Asia and Africa (coincident with the spread of fertile crescent livestock across Europe); historical compilations by Jed Kaplan and colleagues documenting very high early per-capita forest clearance in Europe, thus underpinning simulations of extensive pre-industrial clearance and large CO2 emissions; and wide-ranging studies by Erle Ellis and colleagues of early anthropogenic land transformations in China and elsewhere.

Anaerobic bioremediation of hexavalent uranium in groundwater by reductive precipitation with methanogenic granular sludge.

PubMed

Tapia-Rodriguez, Aida; Luna-Velasco, Antonia; Field, Jim A; Sierra-Alvarez, Reyes

2010-04-01

Uranium has been responsible for extensive contamination of groundwater due to releases from mill tailings and other uranium processing waste. Past evidence has confirmed that certain bacteria can enzymatically reduce soluble hexavalent uranium (U(VI)) to insoluble tetravalent uranium (U(IV)) under anaerobic conditions in the presence of appropriate electron donors. This paper focuses on the evaluation of anaerobic granular sludge as a source of inoculum for the bioremediation of uranium in water. Batch experiments were performed with several methanogenic anaerobic granular sludge samples and different electron donors. Abiotic controls consisting of heat-killed inoculum and non-inoculated treatments confirmed the biological removal process. In this study, unadapted anaerobic granular sludge immediately reduced U(VI), suggesting an intrinsic capacity of the sludge to support this process. The high biodiversity of anaerobic granular sludge most likely accounts for the presence of specific microorganisms capable of reducing U(VI). Oxidation by O(2) was shown to resolubilize the uranium. This observation combined with X-ray diffraction evidence of uraninite confirmed that the removal during anaerobic treatment was due to reductive precipitation. The anaerobic removal activity could be sustained after several respikes of U(VI). The U(VI) removal was feasible without addition of electron donors, indicating that the decay of endogenous biomass substrates was contributing electron equivalents to the process. Addition of electron donors, such as H(2) stimulated the removal of U(VI) to varying degrees. The stimulation was greater in sludge samples with lower endogenous substrate levels. The present work reveals the potential application of anaerobic granular sludge for continuous bioremediation schemes to treat uranium-contaminated water. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Uranium loans: Delaying the day of reckoning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-09-01

Spot market volume so far this year, by NUKEM's estimates, comes to just under 11 million lbs. It appears that existing loans are either being extended, or paid back with material borrowed from other sources. Therefore, there has been no significant amount of purchases on the spot market to pay back borrowed uranium. How do we know the loans have not been paid back with spot purchases For one thing, the amount of uranium loans outstanding has increased. According to our current survey, there may now be as much as 32 million lbs U3O8 equivalent in outstanding loans. At currentmore » prices, it's cheaper to borrow than to buy uranium. So borrowers are gambling that prices will remain low for some time, allowing them to delay repayment of the loans. Borrowers then, in essence, are delaying the day of reckoning on these loans. How long they can do so is anyone's guess. As long as uranium is in abundance and utilities remain willing to lend it out, loan activity will likely remain at or near current levels. But when supplies tighten and the market swings in a more positive direction, borrowers may get caught scrambling to repay their loans as quickly as possible.« less

Solubility classification of airborne uranium products collected at the perimeter of the Allied Chemical Plant, Metropolis, Illinois

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalkwarf, D.R.

1980-05-01

Airborne uranium products were collected at the perimeter of the uranium-conversion plant operated by the Allied Chemical Corporation at Metropolis, Illinois, and the dissolution rates of these products were classified in terms of the ICRP Task Group Lung Model. Assignments were based on measurements of the dissolution half-times exhibited by uranium components of the dust samples as they dissolved in simulated lung fluid at 37/sup 0/C. Based on three trials, the dissolution behavior of dust with aerodynamic equivalent diameter (AED) less than 5.5 ..mu..m and collected nearest the closest residence to the plant was classified 0.40 D, 0.60 Y. Basedmore » on two trials, the dissolution behavior of dust with AED greater than 5.5 ..mu..m and collected at this location was classified 0.37 D, 0.63 Y. Based on one trial, the dissolution behavior of dust with AED less than 5.5 ..mu..m and collected at a location on the opposite side of the plant was classified 0.68 D, 0.32 Y. There was some evidence for adsorption of dissolved uranium onto other dust components during dissolution, and preliminary dissolution trials are recommended for future samples in order to optimize the fluid replacement schedule.« less

DEMONSTRATING SLOW GROWTH RATES IN OPAL FROM Y.M.,NV, USING MICRODIGESTION AND ION-PROBE URANIUM-SERIES DATING

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. PACES; L. NEYMARK; H. PERSING

Thinly laminated (<0.01 mm) opal sheets and globules associated with calcite in fractures and cavities in the unsaturated zone at Yucca Mountain, Nevada, have U concentrations of 50 to 300 ppm. Previous uranium-series thermal ionization mass spectrometry (TIMS) analyses of 0.2- to 1-mm-thick subsamples resulted in a model of slow mineral growth at rates of 0.5 to 5 mm/m.y. To test this growth model using finer sampling resolution, in situ microdigestions were performed by applying a drop of hydrofluoric acid directly to opal surfaces within a small area encircled by jeweler's wax. After several minutes, the liquid was removed, spikedmore » with a tracer solution, and analyzed by TIMS for both U and Th using a single rhenium filament with colloidal graphite. Solutions contained about 0.5 nanograms of U, equivalent to opal weights of 1 to 10 micrograms and dissolved-layer thicknesses less than 0.003 mm. Microdigested opal surfaces have Th-230/U ages of 5 to 10 thousand years (ka) in contrast to much older ages of 150 to 250 ka obtained previously from whole-globule digestions. Additional tests of the growth model were made on cross sections of identical opal globules using the sensitive high-resolution ion microprobe (SHRIMP) with a 0.04-mm-diameter O-minus primary beam. Counting rates for Tho-246 and U-234 varied between 5 and 70 counts per second with Th-230/Th-232 activity ratios typically much greater than a million. The Th-230/U ages in the outer 0.3 mm of the globules ranged from about 30 ka at the outer edge to 400 ka at depth. Ages correlate with microstratigraphic depths and indicate average growth rates between 0.5 and 0.7 mm/m.y. Current U-series data do not resolve differential growth rates related to climate changes during this time period. However, both microdigestion and SHRIMP results confirm the previous TIMS-based model of slow, uniform rates of mineral growth in a hydrologically stable environment.« less

Phanerozoic extensional faulting and alteration control on uranium mineralization in trachytes of the Central Eastern Desert of Egypt

NASA Astrophysics Data System (ADS)

Hamdy, Mohamed M.; Waheeb, Anton G.; Aly, Samir M.; Farag, Nagdy M.; Sadek, Adel F.

2017-12-01

The Gabal Nasb El Atshan Upper Carboniferous-Lower Permian altered trachytes include uranium up to 3165 ppm. The paleostress and resolved shear stress analyses of the deformation systems in Gabal Nasb El Atshan area indicate that the trachyte was subjected to WNW-ESE to E-W tensile shear stress directed extensional regimes. The low-stress regions in the vicinity of extensional faults and their associated joints were favorable locations for fluid flow and the consequence alteration and U-mineralization. This occurred more extensively along the contacts between the sills of trachyte and the Hammamat sedimentary rocks; where the latter acted as a physical barrier for the alteration fluids migration outward. Alteration styles include albitization, aegirinization, arfvedsonization, chloritization and ferruginisation. The albitization is the most common sodic metasomatism, giving sanidine from Or98.8Ab0.7 to Or62.3Ab37.6, anorthoclase from Or51.4Ab48.0 to Or12.2Ab87.6 and albite from Or11.0Ab89.0 to Or0.8Ab99.2. Aegirine and arfvedsonite formed due to decreasing sodium activity in the metasomatic fluids. Sodic metasomatism may be the source of uranium-enrichment, taking place during the late magmatic to deuteric processes. This was followed by a retrograde alteration of chloritization between 175 and 42 °C toward precipitation of Fe-oxides and alteration of primary uranium. Surficial low-temperature alteration remobilized and redistributed the produced uranylhydroxides and ferruginisation caused the reduction and adsorption of U forming betafite, uranophane, soddyite, umohoite, uranotile and uranopilite.

Elevated Uranium in Aquifers of the Jacobsville Sandstone

NASA Astrophysics Data System (ADS)

Sherman, H.; Gierke, J.

2003-12-01

The EPA has announced a new standard for uranium in drinking water of 30 parts per billion (ppb). This maximum contaminant level (MCL) takes effect for community water supplies December 2003. The EPA's ruling has heightened awareness among residential well owners that uranium in drinking water may increase the risk of kidney disease and cancer and has created a need for a quantified, scientific understanding of the occurrence and distribution of uranium isotopes in aquifers. The authors are investigating the occurrence of elevated uranium in northern Michigan aquifers of the Middle Proterozoic Jacobsville sandstone, a red to mottled sequence of sandstones, conglomerates, siltstones and shales deposited as basin fill in the 1.1 Ga Midcontinent rift. Approximately 25% of 300 well water samples tested for isotopic uranium have concentrations above the MCL. Elevated uranium occurrences are distributed throughout the Jacobsville sandstone aquifers stretching across Michigan's Upper Peninsula. However, there is significant variation in well water uranium concentrations (from 0.01 to 190 ppb) and neighboring wells do not necessarily have similar concentrations. The authors are investigating hydrogeologic controls on ground water uranium concentrations in the Jacobsville sandstone, e.g. variations in lithology, mineralogy, groundwater residence time and geochemistry. Approximately 2000' of Jacobsville core from the Amoco St. Amour well was examined in conjunction with the spectral gamma ray log run in the borehole. Spikes in equivalent uranium (eU) concentration from the log are frequently associated with clay and heavy mineral layers in the sandstone core. The lithology and mineralogy of these layers will be determined by analysis of thin sections and x-ray diffraction. A portable spectrometer, model GRS-2000/BL, will be used on the sandstone cliffs along Lake Superior to characterize depositional and lithologic facies of the Jacobsville sandstone in terms of concentrations and ratios of eU, eTh and K. Equipped with borehole accessories, the spectrometer will be used to log residential drinking wells to determine a relationship between the uranium concentration of well water and the eU concentration in the sandstone. Tritium/helium-3 dating will be used to determine whether ground water uranium concentrations increase with residence time. PHREEQCI will be used to model dominate aqueous species of uranium and saturation indices of uranium minerals.

Effects of lead and hydrocarbons from snowmobile exhaust on brook trout (Salvelinus fontinalis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, E.S.

1975-01-01

Lead and hydrocarbons from snowmobile exhaust were found in the water at high levels during the week following ice-out in a Maine pond. Fingerling brook trout (Salvelinus fontinalis) held in fish cages in the pond showed lead and hydrocarbon uptake. These contaminants accumulated during the previous winter when snowmobile operation on the pond was equivalent to one snowmobile burning 250 liters of fuel per season on a .405 hectare pond with average depth of 1 m. Lead content of the water rose from 4.1 ppb before snowmobiling to 135 ppb at ice-out; exposed trout contained 9 to 16 times moremore » lead than controls. Hydrocarbon levels undetectable prior to snowmobiling reached 10 ppm in the water and 1 ppm in exposed fish. Trout held in aquaria for 3 weeks in melted snow containing three different concentrations of snowmobile exhaust also showed lead and hydrocarbon uptake. Their digestive tract tissue contained the most lead (2 ppm) and gills the least (0.2 ppm). Stamina, as measured by the ability to swim against a current, was significantly less in trout exposed to snowmobile exhaust than in control fish. (auth)« less

Cardiovascular protection of deep-seawater drinking water in high-fat/cholesterol fed hamsters.

PubMed

Hsu, Chin-Lin; Chang, Yuan-Yen; Chiu, Chih-Hsien; Yang, Kuo-Tai; Wang, Yu; Fu, Shih-Guei; Chen, Yi-Chen

2011-08-01

Cardiovascular protection of deep-seawater (DSW) drinking water was assessed using high-fat/cholesterol-fed hamsters in this study. All hamsters were fed a high-fat/cholesterol diet (12% fat/0.2% cholesterol), and drinking solutions were normal distiled water (NDW, hardness: 2.48ppm), DSW300 (hardness: 324.5ppm), DSW900 (hardness: 858.5ppm), and DSW1500 (hardness: 1569.0ppm), respectively. After a 6-week feeding period, body weight, heart rates, and blood pressures of hamsters were not influenced by DSW drinking waters. Serum total cholesterol (TC), triacylglycerol (TAG), atherogenic index, and malondialdehyde (MDA) levels were decreased (p<0.05) in the DSW-drinking-water groups, as compared to those in the NDW group. Additionally, increased (p<0.05) serum Trolox equivalent antioxidant capacity (TEAC), and faecal TC, TAG, and bile acid outputs were measured in the DSW-drinking-water groups. Hepatic low-density-lipoprotein receptor (LDL receptor) and cholesterol-7α-hydroxylase (CYP7A1) gene expressions were upregulated (p<0.05) by DSW drinking waters. These results demonstrate that DSW drinking water benefits the attenuation of high-fat/cholesterol-diet-induced cardiovascular disorders in hamsters. Copyright © 2011 Elsevier Ltd. All rights reserved.

Estimation of uranium migration parameters in sandstone aquifers.

PubMed

Malov, A I

2016-03-01

The chemical composition and isotopes of carbon and uranium were investigated in groundwater samples that were collected from 16 wells and 2 sources in the Northern Dvina Basin, Northwest Russia. Across the dataset, the temperatures in the groundwater ranged from 3.6 to 6.9 °C, the pH ranged from 7.6 to 9.0, the Eh ranged from -137 to +128 mV, the total dissolved solids (TDS) ranged from 209 to 22,000 mg L(-1), and the dissolved oxygen (DO) ranged from 0 to 9.9 ppm. The (14)C activity ranged from 0 to 69.96 ± 0.69 percent modern carbon (pmC). The uranium content in the groundwater ranged from 0.006 to 16 ppb, and the (234)U:(238)U activity ratio ranged from 1.35 ± 0.21 to 8.61 ± 1.35. The uranium concentration and (234)U:(238)U activity ratio increased from the recharge area to the redox barrier; behind the barrier, the uranium content is minimal. The results were systematized by creating a conceptual model of the Northern Dvina Basin's hydrogeological system. The use of uranium isotope dating in conjunction with radiocarbon dating allowed the determination of important water-rock interaction parameters, such as the dissolution rate:recoil loss factor ratio Rd:p (a(-1)) and the uranium retardation factor:recoil loss factor ratio R:p in the aquifer. The (14)C age of the water was estimated to be between modern and >35,000 years. The (234)U-(238)U age of the water was estimated to be between 260 and 582,000 years. The Rd:p ratio decreases with increasing groundwater residence time in the aquifer from n × 10(-5) to n × 10(-7) a(-1). This finding is observed because the TDS increases in that direction from 0.2 to 9 g L(-1), and accordingly, the mineral saturation indices increase. Relatively high values of R:p (200-1000) characterize aquifers in sandy-clayey sediments from the Late Pleistocene and the deepest parts of the Vendian strata. In samples from the sandstones of the upper part of the Vendian strata, the R:p value is ∼ 24, i.e., sorption processes are expressed more weakly, and uranium is possibly desorbed from the sediments. Overall, these results provide a better understanding of the evolution of uranium isotopes in groundwater systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reconnaissance for radioactive deposits in the vicinity of Teller and Cape Nome, Seward Peninsula, Alaska, 1946-47

USGS Publications Warehouse

White, Max Gregg; West, W.S.; Matzko, J.J.

1953-01-01

Placer-mining areas and bedrock exposures near Teller on the Seward Peninsula, Alaska, were investigated in June and July, 1946, for possible sources of radioactive materials. The areas that were investigated are: Dese Creek, southeast of Teller; Bluestone River basin, south and southeast of Teller; Sunset Creek and other small streams flowing south into Grantley Harbor, northeast of Teller; and, also northeast of Teller, Swanson Creek and its tributaries, which flow north into the Agiapuk River basin. No significant amount of radioactive material was found, either in the stream gravels or in the bedrock of any of the areas. A heavy-mineral fraction obtained from a granite boulder probably derived from a bench gravel on Gold Run contains 0. 017 percent equivalent uranium, but the radioactivity is due to allanite and zircon. The types of bedrock tested include schist, slate, and greenstone. Readings on fresh surfaces of rock were the same as, or only slightly above the background count. The maximum radioactivity in stream concentrates is 0. 004 percent equivalent uranium in a sluice concentrate from Sunset Creek.

Geophysical interpretation of U, Th, and rare earth element mineralization of the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeast Alaska

USGS Publications Warehouse

McCafferty, Anne E.; Stoeser, Douglas B.; Van Gosen, Bradley S.

2014-01-01

A prospectivity map for rare earth element (REE) mineralization at the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeastern Alaska, was calculated from high-resolution airborne gamma-ray data. The map displays areas with similar radioelement concentrations as those over the Dotson REE-vein-dike system, which is characterized by moderately high %K, eU, and eTh (%K, percent potassium; eU, equivalent parts per million uranium; and eTh, equivalent parts per million thorium). Gamma-ray concentrations of rocks that share a similar range as those over the Dotson zone are inferred to locate high concentrations of REE-bearing minerals. An approximately 1300-m-long prospective tract corresponds to shallowly exposed locations of the Dotson zone. Prospective areas of REE mineralization also occur in continuous swaths along the outer edge of the pluton, over known but undeveloped REE occurrences, and within discrete regions in the older Paleozoic country rocks. Detailed mineralogical examinations of samples from the Dotson zone provide a means to understand the possible causes of the airborne Th and U anomalies and their relation to REE minerals. Thorium is sited primarily in thorite. Uranium also occurs in thorite and in a complex suite of ±Ti±Nb±Y oxide minerals, which include fergusonite, polycrase, and aeschynite. These oxides, along with Y-silicates, are the chief heavy REE (HREE)-bearing minerals. Hence, the eU anomalies, in particular, may indicate other occurrences of similar HREE-enrichment. Uranium and Th chemistry along the Dotson zone showed elevated U and total REEs east of the Camp Creek fault, which suggested the potential for increased HREEs based on their association with U-oxide minerals. A uranium prospectivity map, based on signatures present over the Ross-Adams mine area, was characterized by extremely high radioelement values. Known uranium deposits were identified in the U-prospectivity map, but the largest tract occurs over a radioelement-rich granite phase within the pluton that is likely not related to mineralization. Neither mineralization type displays a well-defined airborne magnetic signature.

Compilation of data on the uranium and equivalent uranium content of samples analyzed by U.S. Geological Survey during a program of sampling mine, mill, and smelter products

USGS Publications Warehouse

Hall, Marlene Louise; Butler, Arthur Pierce

1952-01-01

In 1942 the Geological Survey began to collect, in response to a request made by the War Production Board, samples of mine, mill, and smelter products. About 1,400 such samples were collected and analyzed spectrographically for about 20 elements that were of strategic importance, in order to determine whether any of the products analyzed might be possible sources of some of the needed elements. When attention was directed to radioactive elements in 1943, most of the samples were scanned for radioactivity. Part of the work was done on behalf of the Division of Raw Materials of the Atomic Energy Commission. The sources, mine mill, smelter, or prospect, from which these samples were collected, the kind of material sampled, i.e. ores, concentrates, middlings, tailings, flue dusts, and so forth, and the radioactivity of the samples are listed in this report. Samples of the materials collected in the course of the Geological Survey’s investigations for uranium are excluded, but about 500 such samples were analyzed spectrographically for some or all of the same 20 elements sought in the samples that are the subject of this report. Most of the samples were tested only for their radioactivity, but a few were analyzed chemically for uranium. The radioactivity of many of the samples tested in the early screening was determined only qualitatively. Several samples were tested at one time, and if the count obtained did not exceed a predetermined minimum above background, the samples were not tested individually. If the count was more than this minimum, the samples were tested individually to identify the radioactive sample or samples and to obtain a quantitative value for the radioactivity. In general, the rough screening served as a basis for separating samples in which the radioactivity amount to less than 0.003 percent equivalent uranium from those in which it exceeded that amount. Some aspects of various phases of the investigation of radioactivity in these samples have been reported in various other reports, as follows.

30 CFR 7.86 - Test equipment and specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... balance shall be helium. The mixture shall contain ≤1 part per million equivalent carbon (ppmC), and ≤400... CO2 analyzers shall have purified nitrogen as a diluent. Calibration or span gases for the CH4 analyzer shall be CH4 with purified synthetic air or purified nitrogen as diluent. (19) Calibration or span...

78 FR 78746 - Extension of Tolerances for Emergency Exemptions (Multiple Chemicals)

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

... FIFRA section 18 the use of fenoxaprop-ethyl on grasses grown for seed for control of grassy weeds in... the stoichiometric equivalent of fenoxaprop-ethyl, in or on grass forage and grass hay at 0.05 ppm for... has authorized under FIFRA section 18 the use of bifenazate on timothy grass for control of spider...

Inhalation of diethylamine--acute nasal effects and subjective response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundqvist, G.R.; Yamagiwa, M.; Pedersen, O.F.

1992-03-01

Adult volunteers were exposed to 25 ppm (75 mg/m3) diethylamine in a climate chamber for 15 min in order to study the acute nasal reactions to an exposure equivalent to the present threshold limit value-short-term exposure limit. Changes in nasal volume and nasal resistance were measured by acoustic rhinometry and by rhinomanometry. Acute change in nasal volume, usually seen as acute nasal mucosa response to thermal stimuli, was not observed, nor was an acute change in nasal airway resistance. In a subsequent experiment, the aim was to measure acute sensory effects. Exposure to a concentration increasing from 0 to 12more » ppm took place for 60 min, equal to an average concentration of 10 ppm (30 mg/m3). A moderate to strong olfactory response and distinct nasal and eye irritation were observed. In spite of considerable individual variation, the results were in agreement with sensory effect estimates obtained from animal studies.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

AL-Areqi, Wadeeah M., E-mail: walareqi@yahoo.com; Majid, Amran Ab., E-mail: walareqi@yahoo.com; Sarmani, Sukiman, E-mail: walareqi@yahoo.com

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 LAMPmore » 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.« less

Hazardous Off-Gassing of Carbon Monoxide and Oxygen Depletion during Ocean Transportation of Wood Pellets

PubMed Central

Svedberg, Urban; Samuelsson, Jerker; Melin, Staffan

2008-01-01

Five ocean vessels were investigated for the characterization and quantification of gaseous compounds emitted during ocean transportation of wood pellets in closed cargo hatches from Canada to Sweden. The study was initiated after a fatal accident with several injured during discharge in Sweden. The objective with the investigation was to better understand the off-gassing and issues related to workers' exposure. Air sampling was done during transport and immediately before discharge in the undisturbed headspace air above the wood pellets and in the staircase adjacent to each hatch. The samples were analyzed with Fourier transform infrared spectroscopy and direct reading instruments. The following compounds and ranges were detected in samples from the five ships: carbon monoxide (CO) 1460–14650 ppm, carbon dioxide (CO2) 2960–21570 ppm, methane 79.9–956 ppm, butane equivalents 63–842 ppm, ethylene 2–21.2 ppm, propylene 5.3–36 ppm, ethane 0–25 ppm and aldehydes 2.3–35 ppm. The oxygen levels were between 0.8 and 16.9%. The concentrations in the staircases were almost as high as in the cargo hatches, indicating a fairly free passage of air between the two spaces. A potentially dangerous atmosphere was reached within a week from loading. The conclusions are that ocean transportation of wood pellets in confined spaces may produce an oxygen deficient atmosphere and lethal levels of CO which may leak into adjacent access spaces. The dangerous combination of extremely high levels of CO and reduced oxygen produces a fast-acting toxic combination. Measurement of CO in combination with oxygen is essential prior to entry in spaces having air communication with cargo hatches of wood pellets. Forced ventilation of staircases prior to entry is necessary. Redesign, locking and labeling of access doors and the establishment of rigorous entry procedures and training of onboard crew as well as personnel boarding ocean vessels are also important. PMID:18397907

Hazardous off-gassing of carbon monoxide and oxygen depletion during ocean transportation of wood pellets.

PubMed

Svedberg, Urban; Samuelsson, Jerker; Melin, Staffan

2008-06-01

Five ocean vessels were investigated for the characterization and quantification of gaseous compounds emitted during ocean transportation of wood pellets in closed cargo hatches from Canada to Sweden. The study was initiated after a fatal accident with several injured during discharge in Sweden. The objective with the investigation was to better understand the off-gassing and issues related to workers' exposure. Air sampling was done during transport and immediately before discharge in the undisturbed headspace air above the wood pellets and in the staircase adjacent to each hatch. The samples were analyzed with Fourier transform infrared spectroscopy and direct reading instruments. The following compounds and ranges were detected in samples from the five ships: carbon monoxide (CO) 1460-14650 ppm, carbon dioxide (CO2) 2960-21570 ppm, methane 79.9-956 ppm, butane equivalents 63-842 ppm, ethylene 2-21.2 ppm, propylene 5.3-36 ppm, ethane 0-25 ppm and aldehydes 2.3-35 ppm. The oxygen levels were between 0.8 and 16.9%. The concentrations in the staircases were almost as high as in the cargo hatches, indicating a fairly free passage of air between the two spaces. A potentially dangerous atmosphere was reached within a week from loading. The conclusions are that ocean transportation of wood pellets in confined spaces may produce an oxygen deficient atmosphere and lethal levels of CO which may leak into adjacent access spaces. The dangerous combination of extremely high levels of CO and reduced oxygen produces a fast-acting toxic combination. Measurement of CO in combination with oxygen is essential prior to entry in spaces having air communication with cargo hatches of wood pellets. Forced ventilation of staircases prior to entry is necessary. Redesign, locking and labeling of access doors and the establishment of rigorous entry procedures and training of onboard crew as well as personnel boarding ocean vessels are also important.

Covalent Organic Frameworks as a Decorating Platform for Utilization and Affinity Enhancement of Chelating Sites for Radionuclide Sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Qi; Aguila, Briana; Earl, Lyndsey D.

The potential consequences of nuclear events and the complexity of nuclear waste management motivate the development of selective solid-phase sorbents to provide enhanced protection. In this paper, it is shown that 2D covalent organic frameworks (COFs) with unique structures possess all the traits to be well suited as a platform for the deployment of highly efficient sorbents such that they exhibit remarkable performance, as demonstrated by uranium capture. The chelating groups laced on the open 1D channels exhibit exceptional accessibility, allowing significantly higher utilization efficiency. In addition, the 2D extended polygons packed closely in an eclipsed fashion bring chelating groupsmore » in adjacent layers parallel to each other, which may facilitate their cooperation, thereby leading to high affinity toward specific ions. As a result, the amidoxime-functionalized COFs far outperform their corresponding amorphous analogs in terms of adsorption capacities, kinetics, and affinities. Specifically, COF-TpAb-AO is able to reduce various uranium contaminated water samples from 1 ppm to less than 0.1 ppb within several minutes, well below the drinking water limit (30 ppb), as well as mine uranium from spiked seawater with an exceptionally high uptake capacity of 127 mg g -1. Finally, these results delineate important synthetic advances toward the implementation of COFs in environmental remediation.« less

Covalent Organic Frameworks as a Decorating Platform for Utilization and Affinity Enhancement of Chelating Sites for Radionuclide Sequestration

DOE PAGES

Sun, Qi; Aguila, Briana; Earl, Lyndsey D.; ...

2018-03-27

The potential consequences of nuclear events and the complexity of nuclear waste management motivate the development of selective solid-phase sorbents to provide enhanced protection. In this paper, it is shown that 2D covalent organic frameworks (COFs) with unique structures possess all the traits to be well suited as a platform for the deployment of highly efficient sorbents such that they exhibit remarkable performance, as demonstrated by uranium capture. The chelating groups laced on the open 1D channels exhibit exceptional accessibility, allowing significantly higher utilization efficiency. In addition, the 2D extended polygons packed closely in an eclipsed fashion bring chelating groupsmore » in adjacent layers parallel to each other, which may facilitate their cooperation, thereby leading to high affinity toward specific ions. As a result, the amidoxime-functionalized COFs far outperform their corresponding amorphous analogs in terms of adsorption capacities, kinetics, and affinities. Specifically, COF-TpAb-AO is able to reduce various uranium contaminated water samples from 1 ppm to less than 0.1 ppb within several minutes, well below the drinking water limit (30 ppb), as well as mine uranium from spiked seawater with an exceptionally high uptake capacity of 127 mg g -1. Finally, these results delineate important synthetic advances toward the implementation of COFs in environmental remediation.« less

Application of Optical Imaging Techniques for Quantification of pH and O2 Dynamicsin Porous Media

NASA Astrophysics Data System (ADS)

Li, B.; Seliman, A. F.; Pales, A. R.; Liang, W.; Sams, A.; Darnault, C. J. G.; DeVol, T. A.

2016-12-01

Understanding the spatial and temporal distribution of physical and chemical parameters (e.g. pH, O2) is imperative to characterize the behavior of contaminants in a natural environment. The objectives of this research are to calibrate pH and O2 sensor foils, to develop a dual pH/O2 sensor foil, and to apply them into flow and transport experiments, in order to understand the physical and chemical parameters that control contaminant fate and transport in an unsaturated sandy porous medium. In addition, demonstration of a sensor foil that quantifies aqueous uranium concentration will be presented. Optical imaging techniques will be conducted with 2D tanks to investigate the influence of microbial exudates and plant roots on pH and O2 parameters and radionuclides transport. As a non-invasive method, the optical imaging technique utilizes optical chemical sensor films and either a digital camera or a spectrometer to capture the changes with high temporal and spatial resolutions. Sensor foils are made for different parameters by applying dyes to generate favorable fluorescence that is proportional to the parameter of interest. Preliminary results suggested that this method could detect pH ranging from 4.5 to 7.5. The result from uranium foil test with different concentrations in the range of 2 to 8 ppm indicated that a higher concentration of uranium resulted in a greater color intensity.

Calyptogena-cemented rocks and concretions from the eastern part of Nankai accretionary prism: Age and geochemistry of uranium

NASA Astrophysics Data System (ADS)

Lalou, Claude; Fontugne, Michel; Lallemand, Serge E.; Lauriat-Rage, Agnès

1992-04-01

Calyptogena valves included in a carbonate-rich cement, and fragments of a carbonate-rich chimney, have been examined for their stable isotopic (C and O) composition,14C activity and uranium series disequilibrium. The fossil shells were formed essentially with seawater carbon and a negligible contribution of cold seepage organic carbon, as shown by theirδ13C values. This allows the14C method to be used to determine their age. A fairly good concordance between the14C and230Th234U ages of the youngest shells gives confidence in the dating of the older samples using the latter technique. Thus, theCalyptogena are dated at ca. 150,000 and 20,000 yrs B.P. They have been preserved from dissolution by rapid cementation by a supersaturated carbonate solution. The cement is especially rich in uranium (as high as 75 ppm), whose source is seawater; the enrichment is due to local reducing conditions brought about by the bacterial decomposition of the soft tissues of the bivalves shortly after death. TheCalyptogena that probably developed between these two events (the events of ca. 20,000 and 150,000 yrs) have not been preserved from dissolution because, as is presently the case, the cold seepages were undersaturated with calcium carbonate. The two events probably represent periods of intense fluid venting connected with tectonic activity.

Actual and Idealized Crystal Field Parameterizations for the Uranium Ions in UF 4

NASA Astrophysics Data System (ADS)

Gajek, Z.; Mulak, J.; Krupa, J. C.

1993-12-01

The crystal field parameters for the actual coordination symmetries of the uranium ions in UF 4, C2 and C1, and for their idealizations to D2, C2 v , D4, D4 d , and the Archimedean antiprism point symmetries are given. They have been calculated by means of both the perturbative ab initio model and the angular overlap model and are referenced to the recent results fitted by Carnall's group. The equivalency of some different sets of parameters has been verified with the standardization procedure. The adequacy of several idealized approaches has been tested by comparison of the corresponding splitting patterns of the 3H 4 ground state. Our results support the parameterization given by Carnall. Furthermore, the parameterization of the crystal field potential and the splitting diagram for the symmetryless uranium ion U( C1) are given. Having at our disposal the crystal field splittings for the two kinds of uranium ions in UF 4, U( C2) and U( C1), we calculate the model plots of the paramagnetic susceptibility χ( T) and the magnetic entropy associated with the Schottky anomaly Δ S( T) for UF 4.

Assay for uranium and determination of disequilibrium by means of in situ high resolution gamma-ray spectrometry

USGS Publications Warehouse

Tanner, Allan B.; Moxham, Robert M.; Senftle, F.E.

1977-01-01

Two sealed sondes, using germanium gamma-ray detectors cooled by melting propane, have been field tested to depths of 79 m in water-filled boreholes at the Pawnee Uranium Mine in Bee Co., Texas. When, used as total-count devices, the sondes are comparable in logging speed and counting rate with conventional scintillation detectors for locating zones of high radioactivity. When used with a multichannel analyzer, the sondes are detectors with such high resolution that individual lines from the complex spectra of the uranium and thorium series can be distinguished. Gamma rays from each group of the uranium series can be measured in ore zones permitting determination of the state of equilibrium at each measurement point. Series of 10-minute spectra taken at 0.3- to 0.5-m intervals in several holes showed zones where maxima from the uranium group and from the 222Rn group were displaced relative to each other. Apparent excesses of 230Th at some locations suggest that uranium-group concentrations at those locations were severalfold greater some tens of kiloyears, ago. At the current state of development a 10-minute count yields a sensitivity of about 80 ppm U308. Data reduction could in practice be accomplished in about 5 minutes. The result is practically unaffected by disequilibrium or radon contamination. In comparison with core assay, high-resolution spectrometry samples a larger volume; avoids problems due to incomplete core recovery, loss of friable material to drilling fluids, and errors in depth and marking; and permits use of less expensive drilling methods. Because gamma rays from the radionuclides are accumulated simultaneously, it also avoids the problems inherent in trying to correlate logs made in separate runs with different equipment. Continuous-motion delayed-gamma activation by a 163-?g 252Cf neutron source attached to the sonde yielded poor sensitivity. A better neutron-activation method, in which the sonde is moved in steps so as to place the detector at the previous activation point, could not be evaluated because of equipment failure.

Series hybrid vehicles and optimized hydrogen engine design

NASA Astrophysics Data System (ADS)

Smith, J. R.; Aceves, S.; Vanblarigan, P.

1995-05-01

Lawrence Livermore, Sandia Livermore and Los Alamos National Laboratories have a joint project to develop an optimized hydrogen fueled engine for series hybrid automobiles. The major divisions of responsibility are: system analysis, engine design and kinetics modeling by LLNL; performance and emission testing, and friction reduction by SNL; computational fluid mechanics and combustion modeling by LANL. This project is a component of the Department of Energy, Office of Utility Technology, National Hydrogen Program. We report here on the progress on system analysis and preliminary engine testing. We have done system studies of series hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. The impact of various on-board storage options on fuel economy are evaluated. Experiments with an available engine at the Sandia Combustion Research Facility demonstrated NO(x) emissions of 10 to 20 ppm at an equivalence ratio of 0.4, rising to about 500 ppm at 0.5 equivalence ratio using neat hydrogen. Hybrid vehicle simulation studies indicate that exhaust NO(x) concentrations must be less than 180 ppm to meet the 0.2 g/mile California Air Resources Board ULEV or Federal Tier-2 emissions regulations. We have designed and fabricated a first generation optimized hydrogen engine head for use on an existing single cylinder Onan engine. This head currently features 14.8:1 compression ratio, dual ignition, water cooling, two valves and open quiescent combustion chamber to minimize heat transfer losses.

Quasi-Static Compression and Tensile Stress-Strain Curves, Tantalum - 10% Tungsten and 300 Grade Maraging Steel

DTIC Science & Technology

1986-05-01

available high density metal. It was investigated as a practical substitute for ballistic tungsten or uranium alloys. It was also used as a core material... PPM ) H ɝ ɝ ɝ C ᝺ ណ ណ N 12 ɝ 7 0 41 អ 60 Si ម ម Ti ង V ង ង ង Cr ᝺ ង ង Fe ង ម ម Co ង ᝺ ᝺ Ni ង ង ង Cu...3M Tri-M- ite WETORDRY trademark silicon carbide paper, wet with a trichloroethane base coolant, to remove about 0.05 mm in the center. An 0.1

Radionuclides from past uranium mining in rivers of Portugal.

PubMed

Carvalho, Fernando P; Oliveira, João M; Lopes, Irene; Batista, Aleluia

2007-01-01

During several decades and until a few years ago, uranium mines were exploited in the Centre of Portugal and wastewaters from uranium ore milling facilities were discharged into river basins. To investigate enhancement of radioactivity in freshwater ecosystems, radionuclides of uranium and thorium series were measured in water, sediments, suspended matter, and fish samples from the rivers Vouga, Dão, Távora and Mondego. The results show that these rivers carry sediments with relatively high naturally occurring radioactivity, and display relatively high concentrations of radon dissolved in water, which is typical of a uranium rich region. Riverbed sediments show enhanced concentrations of radionuclides in the mid-section of the Mondego River, a sign of past wastewater discharges from mining and milling works at Urgeiriça confirmed by the enhanced values of (238)U/(232)Th radionuclide ratios in sediments. Radionuclide concentrations in water, suspended matter and freshwater fish from that section of Mondego are also enhanced in comparison with concentrations measured in other rivers. Based on current radionuclide concentrations in fish, regular consumption of freshwater species by local populations would add 0.032 mSv a(-1) of dose equivalent (1%) to the average background radiation dose. Therefore, it is concluded that current levels of enhanced radioactivity do not pose a significant radiological risk either to aquatic fauna or to freshwater fish consumers.

Migration behavior of naturally occurring radionuclides at the Nopal I uranium deposit, Chihuahua, Mexico

NASA Astrophysics Data System (ADS)

Prikryl, James D.; Pickett, David A.; Murphy, William M.; Pearcy, English C.

1997-04-01

Oxidation of pyrite at the Nopal I uranium deposit, Peña Blanca district, Chihuahua, Mexico has resulted in the formation of Fe-oxides/hydroxides. Anomalous U concentrations (i.e. several hundred to several thousand ppm) measured in goethite, hematite, and amorphous Fe-oxyhydroxides in a major fracture that crosscuts the deposit and the absence of U minerals in the fracture suggest that U was retained during secondary mineral growth or sorbed on mineral surfaces. Mobilization and transport of U away from the deposit is suggested by decreasing U concentrations in fracture-infilling materials and in goethite and hematite with distance from the deposit. Greater than unity {234U}/{238U} activity ratios measured in fracture-infilling materials indicate relatively recent ( < 1 Ma) U uptake from fluids that carried excess 234U. Systematic decreases in {234U}/{238U} activity ratios of fracture materials with distance from the deposit suggest a multistage mobilization process, such as remobilization of U from 234U-enriched infill minerals or differential or diminished transport of U-bearing solutions containing excess 234U.

The effect of ion irradiation on the dissolution of UO 2 and UO 2 -based simulant fuel

DOE PAGES

Popel, Aleksej J.; Wietsma, Thomas W.; Engelhard, Mark H.; ...

2017-11-21

Our aim is to study the separate effect of fission fragment damage on the dissolution of simulant UK advanced gas-cooled reactor nuclear fuel in water. Plain UO 2 and UO 2 samples, doped with inactive fission products to simulate 43 GWd/tU of burn-up, were fabricated. A set of these samples were then irradiated with 92 MeV 129Xe 23+ ions to a fluence of 4.8 × 10 15 ions/cm 2 to simulate the fission damage that occurs within nuclear fuels. The primary effect of the irradiation on the UO 2 samples, observed by scanning electron microscopy, was to induce a smootheningmore » of the surface features and formation of hollow blisters, which was attributed to multiple overlap of ion tracks. Dissolution experiments were conducted in single-pass flow-through (SPFT) mode under anoxic conditions (<0.1 O 2 ppm in Ar) to study the effect of the induced irradiation damage on the dissolution of the UO 2 matrix with data collection capturing six minute intervals for several hours. These time-resolved data showed that the irradiated samples showed a higher initial release of uranium than unirradiated samples, but that the uranium concentrations converged towards ~10 -9 mol/l after a few hours. And apart from the initial spike in uranium concentration, attributed to irradiation induced surficial micro-structural changes, no noticeable difference in uranium chemistry as measured by X-ray electron spectroscopy or ‘effective solubility’ was observed between the irradiated, doped and undoped samples in this work. Some secondary phase formation was observed on the surface of UO 2 samples after the dissolution experiment.« less

The effect of ion irradiation on the dissolution of UO 2 and UO 2 -based simulant fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popel, Aleksej J.; Wietsma, Thomas W.; Engelhard, Mark H.

Our aim is to study the separate effect of fission fragment damage on the dissolution of simulant UK advanced gas-cooled reactor nuclear fuel in water. Plain UO 2 and UO 2 samples, doped with inactive fission products to simulate 43 GWd/tU of burn-up, were fabricated. A set of these samples were then irradiated with 92 MeV 129Xe 23+ ions to a fluence of 4.8 × 10 15 ions/cm 2 to simulate the fission damage that occurs within nuclear fuels. The primary effect of the irradiation on the UO 2 samples, observed by scanning electron microscopy, was to induce a smootheningmore » of the surface features and formation of hollow blisters, which was attributed to multiple overlap of ion tracks. Dissolution experiments were conducted in single-pass flow-through (SPFT) mode under anoxic conditions (<0.1 O 2 ppm in Ar) to study the effect of the induced irradiation damage on the dissolution of the UO 2 matrix with data collection capturing six minute intervals for several hours. These time-resolved data showed that the irradiated samples showed a higher initial release of uranium than unirradiated samples, but that the uranium concentrations converged towards ~10 -9 mol/l after a few hours. And apart from the initial spike in uranium concentration, attributed to irradiation induced surficial micro-structural changes, no noticeable difference in uranium chemistry as measured by X-ray electron spectroscopy or ‘effective solubility’ was observed between the irradiated, doped and undoped samples in this work. Some secondary phase formation was observed on the surface of UO 2 samples after the dissolution experiment.« less

Remote Sensing and GIS Methods to Detect Uranium Contamination in Watersheds on the Navajo Nation: A NASA/AIHEC Summer Research Experience

NASA Astrophysics Data System (ADS)

Chaco, E.; Robinson, D. K.; Carlson, M.; Rock, B. N.

2010-12-01

Using ground-based mapping of private drinking water wells contaminated with uranium, we developed Landsat Thematic Mapper (TM) band combinations which indicate possible contamination of extensive areas along the Polacca Wash, the Cottonwood Wash and the Balakai Wash below Black Mesa on the Navajo Nation. The project built on water quality samples taken on unregulated wells by a Field Research Water Quality Team from Dine’ College. The Nevada State Health Laboratory analyzed twenty-six samples, and of those, 12 wells showed uranium in exceedance of 13 μR/hr, the equivalent of 114 mrem per year, greater than the Nuclear Regulatory Commission’s exposure limit of 100 mrem per year. This project hypothesized that point locations of contaminated wells could be compared with US Geologic Survey National Uranium Resource Evaluation (NURE) measures of high uranium levels in soil to identify other possible areas of contamination. We used Cluster Analysis remote sensing methods from MultiSpec© with data acquired by Landsat 5-TM satellite to produce a false color composite band combination, (7 4 2/R G B). Overlaid with a geological map, the Landsat classification correlated sections of sediment with pixilated colored minerals in the NURE data. This map shows possible high levels of uranium in the soil in the watersheds below mine and mill locations. Ground truth studies are needed to confirm the presence of uranium at these suspected sites. The larger goal of this study is to help solve the uranium contamination problem for the Navajo Nation. Chaco was one of 21 TCU (Tribal Colleges and Universities) students who participated in the 2010 NASA/AIHEC (National Aeronautics and Space Administration/American Indian Higher Education Council) Summer Research Experience program. Robinson was his TCU faculty mentor, and Carlson and Rock were Summer Research Experience instructors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swift, Barry D.; Tarantino, Joseph J., P. E.

The Paducah Gaseous Diffusion Plant (PGDP), owned by the Department of Energy (DOE), has been enriching uranium since the early 1950s. The enrichment process involves electrical and mechanical components that require periodic cleaning. The primary cleaning agent was trichloroethene (TCE) until the late 1980s. Historical documentation indicates that a mixture of TCE and dry ice were used at PGDP for testing the integrity of steel cylinders, which stored depleted uranium. TCE and dry ice were contained in a below-ground pit and used during the integrity testing. TCE seeped from the pit and contaminated the surrounding soil. The Lasagna{trademark} technology wasmore » identified in the Record of Decision (ROD) as the selected alternative for remediation of the cylinder testing site. A public-private consortium formed in 1992 (including DOE, the U.S. Environmental Protection Agency, and the Kentucky Department for Environmental Protection, Monsanto, DuPont, and General Electric) developed the Lasagna{trademark} technology. This innovative technology employs electrokinetics to remediate soil contaminated with organics and is especially suited to sites with low permeability soils. This technology uses direct current to move water through the soil faster and more uniformly than hydraulic methods. Electrokinetics moves contaminants in soil pore water through treatment zones comprised of iron filings, where the contaminants are decomposed to basic chemical compounds such as ethane. After three years of development in the laboratory, the consortium field tested the Lasagna{trademark} process in several phases. CDM installed and operated Phase I, the trial installation and field test of a 150-square-foot area selected for a 120-day run in 1995. Approximately 98 percent of the TCE was removed. CDM then installed and operated the next phase (IIa), a year-long test on a 600-square-foot site. Completed in July 1997, this test removed 75 percent of the total volume of TCE down to a depth of 45 feet. TCE in the test sites. Based on the successful field tests (Phases I and IIa), the ROD was prepared and the Lasagna{trademark} alternative was selected for remediation of TCE contaminated soils at the cylinder testing site Solid Waste Management Unit 91(SWMU 91). Bechtel Jacobs Company LLC contracted CDM to construct and operate a full-scale Lasagna{trademark} remediation system at the site (Phase IIb). Construction began in August 1999 and the operational phase was initiated in December 1999. The Lasagna{trademark} system was operated for two years and reduced the average concentration of TCE in SWMU 91 soil from 84 ppm to less than 5.6 ppm. Verification sampling was conducted during May, 2002. Results of the verification sampling indicated the average concentration of TCE in SWMU 91 soil was 0.38 ppm with a high concentration of 4.5 ppm.« less

Measuring and predicting the transport of actinides and fission product contaminants in unsaturated prairie soil

NASA Astrophysics Data System (ADS)

Sims, D. J.

Soil samples have been taken in 2001 from the area of a 1951 release from an underground storage tank of 6.7 L of an aqueous solution of irradiated uranium (360 GBq). A simulation of the dispersion of the actinides and fission products was conducted in the laboratory using irradiated natural uranium, non-irradiated natural uranium and metal standards dissolved in acidic aqueous solutions and added to soil columns containing uncontaminated prairie soil. The lab soil columns were allowed 12 to 14 months for contaminant transport. Soil samples were analyzed using gamma-ray spectroscopy, neutron activation analysis (NAA) and liquid scintillation counting (LSC) to determine the elemental concentrations of U, Cs and Sr. Diffusion coefficients from the 50 year soil samples and the lab soil samples were determined. The measured diffusion coefficients from the field samples were 3.0 x 10-4 cm2 s-1 (Cs-137), 1.8 x 10-5 cm2 s-1 (U-238) and 2.6 x 10-3 cm2 s-1 (Sr-90) and the values determined from lab simulation were 5 x 10-6 cm 2 s-1 (Cs-137), 3 x 10-5 cm2 s-1 (U-238) and 1.9 x 10-5 cm 2 s-1 (Sr-90). The differences between the sets of diffusion coefficients can be attributed to differences in retardation effects, weather effects and changes in the soil characteristics when transporting, such as porosity. The analytical work showed that Cs-137 content of soil can be determined effectively using gamma-ray spectroscopy; U-238 content can be measured using NAA; and Sr-90 content can be measured using LSC. For non- and low-radioactive species, it was shown that both flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma-mass spectrometry (ICP-MS) gave comparable results for Sr, Cs and Sm, with the average values ranging from 0.5 to 4.5 ppm of each other. The U-238 content results from NAA and from ICP-MS showed general agreement with an average difference of 81.3 ppm on samples having concentrations up to 988.2 ppm. The difference may have been due to matrix interference. It was determined through finite element modeling that 250 years after the 1951 release, the soil concentration of the three contaminant of U-238, Sr-90 and Cs-137 will be less than their respective soil clearance level values and therefore will not pose a long term environmental hazard. The fastest nuclide to reach the water table, at a depth of 45 m below the surface, at Suffield Site 27 was calculated to be Sr-90 after a period of 15,000 years. Therefore, it is not necessary to remove the subsurface soil at Site 27 for site decontamination but it is recommended that a "no-digging" policy, except for scientific research, be enforced at this site.

In vitro dentine remineralization with a potential salivary phosphoprotein homologue.

PubMed

Romero, Maria Jacinta Rosario H; Nakashima, Syozi; Nikaido, Toru; Sadr, Alireza; Tagami, Junji

2016-08-01

Advantages of introducing a salivary phosphoprotein homologue under standardized in vitro conditions to simulate the mineral-stabilizing properties of saliva have been proposed. This study longitudinally investigates the effects of casein, incorporated as a potential salivary phosphoprotein homologue in artificial saliva (AS) solutions with/without fluoride (F) on in vitro dentine lesion remineralization. Thin sections of bovine root dentine were demineralized and allocated randomly into 6 groups (n=18) having equivalent mineral loss (ΔZ) after transverse microradiography (TMR). The specimens were remineralized using AS solutions containing casein 0μg/ml, F 0ppm (C0-F0); casein 0μg/ml, F 1ppm (C0-F1); casein 10μg/ml, F 0ppm (C10-F0); casein 10μg/ml, F 1ppm (C10-F1); casein 100μg/ml, F 0ppm (C100-F0) or casein 100μg/ml, F 1ppm (C100-F1) for 28days with TMR taken every 7 days. Surface mineral precipitation, evident in group C0-F1, was apparently inhibited in groups with casein incorporation. Repeated measures ANOVA with Bonferroni correction revealed higher ΔZ for non-F and non-casein groups than for their counterparts (p<0.001). Subsequent multiple comparisons showed that mineral gain was higher (p<0.001) with 10μg/ml casein than with 100μg/ml when F was present in the earlier stages of remineralization, with both groups achieving almost complete remineralization after 28 days. Casein is a potential salivary phosphoprotein homologue that could be employed for in vitro dentine remineralization studies. Concentration related effects may be clinically significant and thus must be further examined. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Role of Technology for Achieving Climate Policy Objectives: Overview of the EMF 27 Study on Technology Strategies and Climate Policy Scenarios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kriegler, Elmar; Weyant, John; Blanford, Geoffrey J.

2014-04-01

This article presents the synthesis of results from the Stanford Energy Modeling Forum Study 27, an inter-comparison of 19 energy-economy and integrated assessment models. The study investigated the value of individual mitigation technologies such as energy intensity improvements, carbon capture and sequestration (CCS), nuclear power, solar and wind power and bioenergy for climate mitigation. Achieving atmospheric greenhouse gas concentration targets at 450 and 550 ppm CO2 equivalent requires massive greenhouse gas emissions reductions. A fragmented policy approach at the level of current ambition is inconsistent with these targets. The availability of a negative emissions technology, in most models biofuels withmore » CCS, proved to be a key element for achieving the climate targets. Robust characteristics of the transformation of the energy system are increased energy intensity improvements and the electrification of energy end use coupled with a fast decarbonization of the electricity sector. Non-electric energy end use is hardest to decarbonize, particularly in the transport sector. Technology is a key element of climate mitigation. Versatile technologies such as CCS and bioenergy have largest value, due in part to their combined ability to produce negative emissions. The individual value of low-carbon power technologies is more limited due to the many alternatives in the sector. The scale of the energy transformation is larger for the 450 ppm than for the 550 ppm CO2e target. As a result, the achievability and the costs of the 450 ppm target are more sensitive to variations in technology variability. Mitigation costs roughly double when moving from 550 ppm to 450 ppm CO2e, but remain below 3% of GDP for most models.« less

Subacute toxicity of nano-selenium compared to other selenium species in mice.

PubMed

Benko, Ilona; Nagy, Gabor; Tanczos, Bence; Ungvari, Eva; Sztrik, Attila; Eszenyi, Peter; Prokisch, Jozsef; Banfalvi, Gaspar

2012-12-01

Sixteen groups of mice were fed diets containing different selenium species to compare their toxicity. Inorganic sodium selenate and sodium hydroselenite, elementary nanoSe, organic Sel-Plex, and Lacto-MicroSelenium were administered for 14 d at concentrations of 0.5, 5, and 50 ppm Se, equivalent to 0.5, 5, and 50 mg Se/kg food, corresponding to an estimated 4, 40, and 400 µg/kg body weight/d Se uptake, respectively. At the end of the treatment, body, liver, spleen, kidney, heart, and brain weights were measured, mice were subjected to necropsy, and histological examinations were performed on the liver. At lower Se doses (0.5 and 5 ppm) a moderate reduction was observed in the number of bone marrow and white blood cells and in granulocyte-macrophage colony-forming units (GM-CFUs) relative to the untreated control group of mice. A comparison of lowest toxic doses of sodium selenite in mice (0.5 ppm) and mallard (10 ppm) indicates that birds are more resistant to Se than rodents. In mice, a small but measurable weight loss was observed after 5 ppm selenate and LactoMicroSe treatment. The most significant changes took place after 50-ppm administration in body and spleen weight, hematology, and liver histology. Toxicity was more pronounced when inorganic Se was applied than after subacute application of Sel-Plex, nanoSe, or LactoMicroSe. To summarize the effects, the authors' 14-d murine subacute toxicity study showed that the toxicity of Se species decreased in the following order: selenate > selenite > nanoSe > Sel-Plex > LactoMicroSe. Copyright © 2012 SETAC.

Data from geologic investigations in the Yemen Arab Republic during 1976

USGS Publications Warehouse

Grolier, Maurice J.; Domenico, J.A.; Donato, Mary; Tibbitts, G.C.; Overstreet, W.C.; Ibrahim, Mohammad Mukred

1977-01-01

The results of semiquantitative spectrographic analyses for 31 elements in 126 specimens of rocks from the Yemen Arab Republic, collected mainly during February 1976 from the Precambrian area in the southeastern part of the country, provide background data for use in geochemical evaluation of areas potentially favorable for mineral deposits. Gold and thorium were undetected; the lower limits of determination are 10 parts per million (ppm) and 20 ppm, respectively. For the other elements, the abundances follow geochemical norms for crustal distribution: (1) Fe, Nb, and Zr in Holocene weathering products; (2) Ca and Sr in Pliocene limestone; (3) Mo in Pliocene(?) or Miocene(?) dikes; (4) Be, La, and Sn in Miocene(?) alkalic granite; (5) As, Be, and La in Tertiary and/or Cretaceous felsic tuff; (6) V in Tertiary and/or Cretaceous carbonaceous sedimentary rocks interbedded with volcanic rocks; (7) Be, La, Sn, and Zr in Tertiary and/or Cretaceous undivided volcanics; (8) Sn and W in Precambrian felsite and pegmatite; (9) Co, Cr, Ni, and Ti in Precambrian mafic rocks; (10) Mg and Sr in Precambrian marble and calcsilicate rocks; (11) Y in Precambrilan schist; (12) B and Sc dispersed in rocks of many ages; and (13) Ag, Ba, Bi, Cd, Cu, Mn, Pb, Sb, Sn, and Zn in a hydrothermal replacement deposit in Precambrian sediment. None of the rocks contained as much as 205 ppm equivalent uranium. The highest values for Ag, Cu, Pb, Zn, and Cd were obtained on a sample of hydrothermally altered siltstone not personally collected by the writers. It was said to have come from the Ma'rib area in the eastern part of the Yemen Arab Republic. The source must be studied, because this single sample is high-grade base-metal ore. Among the samples collected by the writers, the economically most significant are altered tuffs, ignimbrites, and felsites exposed between Jibal Hufash and Manakhah on the road from Hudaydah to San'a'. They are strongly anomalous for As and weakly anomalous, variously, for Hg, Mo, and Pb, which elements may constitute an epigenetic dispersion pattern from hidden sulfide deposits. Inasmuch as chalcopyrite and native copper have been reported in the vicinity of Jabal Haraz in the Manakhah area, the rocks of the Yemen Volcanics in this region should be explored for base-metal sulfide deposits. The first results of paleontologic examinations of fossils collected during 1975 and 1976 are presented, as are a list of Landsat images covering the Yemen Arab Republic, and a selected bibliography of reports on geology and the allied sciences relating to the Yemen Arab Republic.

Reconnaissance for radioactive rocks in the Paulo Afonso Region, Bahia, Brazil

USGS Publications Warehouse

Haynes, Donald D.; Mau, Henry

1958-01-01

Ground and air traverses were made to the northwest, north and northeast of Paulo Afonso, Bahia, Brazil, covering Precambrian crystalline rocks and sedimentary rocks of the Jatoba series of Jurassic or Cretaceous age. No important radioactivity anomalies were found; samples from the two strongest anomalies had an equivalent uranium-oxide content of 0.002 percent and 0.006 percent.

Late accretion to the Moon recorded in zircon (U-Th)/He thermochronometry

NASA Astrophysics Data System (ADS)

Kelly, Nigel M.; Flowers, Rebecca M.; Metcalf, James R.; Mojzsis, Stephen J.

2018-01-01

We conducted zircon (U-Th)/He (ZHe) analysis of lunar impact-melt breccia 14311 with the aim of leveraging radiation damage accumulated in zircon over extended intervals to detect low-temperature or short-lived impact events that have previously eluded traditional isotopic dating techniques. Our ZHe data record a coherent date vs. effective Uranium concentration (eU) trend characterized by >3500 Ma dates from low (≤75 ppm) eU zircon grains, and ca. 110 Ma dates for high (≥100 ppm) eU grains. A progression between these date populations is apparent for intermediate (75-100 ppm) eU grains. Thermal history modeling constrains permissible temperatures and cooling rates during and following impacts. Modeling shows that the data are most simply explained by impact events at ca. 3950 Ma and ca. 110 Ma, and limits allowable temperatures of heating events between 3950-110 Ma. Modeling of solar cycling thermal effects at the lunar surface precludes this as the explanation for the ca. 110 Ma ZHe dates. We propose a sample history characterized by zircon resetting during the ca. 3950 Ma Imbrium impact event, with subsequent heating during an impact at ca. 110 Ma that ejected the sample to the vicinity of its collection site. Our data show that zircon has the potential to retain 4He over immense timescales (≥3950 Myrs), thus providing a valuable new thermochronometer for probing the impact histories of lunar samples, and martian or asteroidal meteorites.

Acute behavioural comparisons of toluene and ethanol in human subjects.

PubMed

Echeverria, D; Fine, L; Langolf, G; Schork, T; Sampaio, C

1991-11-01

A comparison of toluene and ethanol (EtOH) induced changes in central nervous system (CNS) function and symptoms were evaluated in two studies, and when possible the effects of toluene were expressed in EtOH equivalent units. The toluene concentrations were 0, 75, and 150 ppm, bracketing the American Conference of Governmental Industrial Hygienists threshold limit value (ACGIH TLV) of 100 ppm. The socially relevant EtOH doses were 0.00, 0.33, and 0.66 g EtOH/kg body weight, equivalent to two and four 3.5% 12 ounce beers. Forty two paid college students were used in each study. In the first study, subjects were exposed to toluene and an odour masking agent menthol (0.078 ppm) for seven hours over three days. In the second study EtOH or a placebo was administered at 1530 across three days also in the presence of menthol. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory), perception (pattern recognition), psychomotor skill (simple reaction time, continuous performance, symbol-digit, hand-eye coordination, finger tapping, and critical tracking), manual dexterity (one hole), mood (profile on mood scales (POMS), fatigue (fatigue checklist), and verbal ability were evaluated at 0800, 1200, and 1600. Voluntary symptoms and observations of sleep were collected daily. A 3 x 3 latin square design evaluated solvent effects simultaneously controlling for learning and dose sequence. An analysis of variance and test for trend were performed on am-pm differences reflecting an eight hour workday and on pm scores for each solvent, in which subjects were their own control Intersubject variation in absorbance was monitored in breath. A 5 to 10% decrement was considered meaningful if consistent with a linear trend at p less than 0.05. At 150 ppm toluene, losses in performance were 6.0% for digit span, 12.1% for pattern recognition (latency), 5% for pattern memory (number correct), 6.5% for one hole, and 3% for critical tracking. The number of headaches and eye irritation also increased in a dose-response manner. The greatest effect was found for an increasing number of observations of sleep. A range of 2 to 7% decrements suggest the ACGIH TLV of 100 ppm toluene may be a good estimate of the biological threshold supporting a re-evaluation of the TLV. At 0.66 g EtOH/kg body weight symptoms and performance decrements were 6.6% for digit span, 9.2% for pattern recognition, 4.0% for continuous performance, 7.9% for symbol-digit, 16.5% for finger tapping, 6.2% for critical tracking, and 5.2% for the one hole test. The EtOH equivalents at 150 ppm toluene for digit span (0.56g EtOH/kg/body weight), the latency for pattern recognition (0.66 g EtOH kg body weight), and the one hole element "move" (0.37 g EtOH kg body weight) show that the first two measures would be affected at or above the 50 mg% blood alcohol concentration. This concentration is recognised as the lowest alcohol concentration associated with increased numbers of automobile accidents. The results suggest that EtOH may be a useful acute standard to compare the effects of various industrial solvents and support investigating an association between exposure to solvents and increased risk to safety in industry.

Temperature dependence of the magnetostriction in polycrystalline PrFe{sub 1.9} and TbFe{sub 2} alloys: Experiment and theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Y. M.; College of Physics and Technology, Guangxi Normal University, Guilin, GuangXi; Chen, L. Y.

2014-05-07

A remarkable magnetostriction λ{sub 111} as large as 6700 ppm was found at 70 K in PrFe{sub 1.9} alloy. This value is even larger than the theoretical maximum of 5600 ppm estimated by the Steven's equivalent operator method. The temperature dependence of λ{sub 111} for PrFe{sub 1.9} and TbFe{sub 2} alloys follows well with the single-ion theory rule, which yields giant estimated λ{sub 111} values of about 8000 and 4200 ppm for PrFe{sub 1.9} and TbFe{sub 2} alloys, respectively, at 0 K. The easy magnetization direction of PrFe{sub 1.9} changes from [111] to [100] as temperature decreases, which leads to the abnormal decrease of themore » magnetostriction λ. The rare earth sublattice moment increases sharply in PrFe{sub 1.9} alloy with decreasing temperature, resulting in the remarkably largest estimated value of λ{sub 111} at 0 K according to the single-ion theory.« less

KINETICS OF THE DISSOLUTION OF URANIUM DIOXIDE IN CARBONATE-BICARBONATE SOLUTIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schortmann, W.E.; DeSesa, M.A.

The kinetics of the dissolution of uranium dioxide in sodium carbonate- sodium bicarbonate solutions were determined. The study was undertaken in order to obtain fundamental information about the commercial carbonate process for leaching uranium from its ores. A rate equation incorporating the effects of surface area oxygen partial pressure, temperature, and reagent concentrations was empirically developed. A mechanism consisting essentially of two consecutive reactions at steady state is proposed. These reactions are the oxidation of U/ sup 4+/ to U/sup 6+/ and the subsequent formation of the uranyl dicarbonate complexion. Depending on the conditions, either or both of these reactionsmore » can determine the over-all rate. The conversion of uranyl dicarbonate to the uranyl tricarbonate complexion is postulated to be very rapid. In the suggested mechanism, the rate-determining phase of the oxidation is the dissociation of adsorbed molecular oxygen. and both the carbonate and bicarbonate ions play equivalent roles in the formation of the uranyl dicarbonate. As indicated by their high activation energies of about 13 and 14 kcal per mole uranium, both reactions are chemical rather than diffusional processes. A mathematical examination of the proposed mechanism produced a rate equation consistent with the experimental information. The credibility of the mechanism was thereby strengthened. (auth)« less

Estimate of contribution of jet aircraft operations to trace element concentration at or near airports

NASA Technical Reports Server (NTRS)

Fordyce, J. S.; Sheibley, D. W.

1974-01-01

Samples of ASTM type A jet fuel were analyzed for trace-element content by instrumental neutron activation techniques. Forty-nine elements were sought. Only ten, aluminum, gold, indium, lanthanum, titanium, vandium, barium, dysprosium, tellurium, and uranium, were observed at levels above the detection limits encountered; of these only aluminum, titanium, and barium were present at concentrations greater than 0.1 ppm. Estimates of exhaust gas concentrations are made, and the ambient contribution at or near airports is calculated by using the Los Angeles International Airport dispersion model. It is shown that the ambient contribution is about an order of magnitude below typical urban levels for virtually all elements sought.

Estimate of contribution of jet aircraft operations to trace element concentration at or near airports

NASA Technical Reports Server (NTRS)

Fordyce, J. S.; Sheibley, D. W.

1975-01-01

Samples of ASTM type A jet fuel were analyzed for trace element content by instrumental neutron activation techniques. Forty-nine elements were sought. Only ten, aluminum, gold, indium, lanthanum, titanium, vanadium, barium, dysprosium, tellurium, and uranium, were observed at levels above the detection limits encountered; of these only aluminum, titanium, and barium were present at concentrations greater than 0.1 ppm. Estimates of exhaust gas concentrations are made, and the ambient contribution at or near airports is calculated by using the Los Angeles International Airport dispersion model. It is shown that the ambient contribution is about an order of magnitude below typical urban levels for virtually all elements sought.

The influence of impurities on the crystal structure and mechanical properties of additive manufactured U–14at.% Nb

DOE PAGES

Wu, Amanda S.; Brown, Donald W.; Clausen, Bjørn; ...

2017-03-01

Uranium-niobium alloys can exist with significantly different microstructures and mechanical properties, heavily influenced by thermomechanical processing history and impurities. In this study, the influence of Ti and other impurities is studied on uranium-14 at.% niobium additively manufactured using laser powder bed fusion. In two different metallic impurity levels were investigated and a Nb equivalent (Nbeq) composition is defined to represent the impurities. Furthermore, in-situ neutron diffraction during compression loading shows that increased Nbeq promotes the formation of γ°-tetragonal phase at the expense of α''-monoclinic phase, resulting in 2 × higher yield strength than water quenched α'' and a strain inducedmore » transformation to α'' with superelastic strains to 4.5%.« less

The influence of impurities on the crystal structure and mechanical properties of additive manufactured U–14at.% Nb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Amanda S.; Brown, Donald W.; Clausen, Bjørn

Uranium-niobium alloys can exist with significantly different microstructures and mechanical properties, heavily influenced by thermomechanical processing history and impurities. In this study, the influence of Ti and other impurities is studied on uranium-14 at.% niobium additively manufactured using laser powder bed fusion. In two different metallic impurity levels were investigated and a Nb equivalent (Nbeq) composition is defined to represent the impurities. Furthermore, in-situ neutron diffraction during compression loading shows that increased Nbeq promotes the formation of γ°-tetragonal phase at the expense of α''-monoclinic phase, resulting in 2 × higher yield strength than water quenched α'' and a strain inducedmore » transformation to α'' with superelastic strains to 4.5%.« less

Measurement of natural radioactivity and radon exhalation rate from rock samples of Jaduguda uranium mines and its radiological implications

NASA Astrophysics Data System (ADS)

Mahur, A. K.; Kumar, Rajesh; Sonkawade, R. G.; Sengupta, D.; Prasad, Rajendra

2008-04-01

The Singhbhum shear zone is a 200 km long arcuate belt in Jharkhand state situated in eastern India. The central part between Jaduguda-Bhatin-Nimdih, Narwapahr-Garadih-Turamdih is rich in uranium. Presence of uranium in the host rocks and the prevalence of a confined atmosphere within mines could result in enhanced concentration of radon (222Rn) gas and its progeny. Inhalation of radon daughter products is a major contributor to the radiation dose to exposed subjects. By using high resolution γ-ray spectroscopic system various radionuclides in the rock samples, collected from different places of Jaduguda uranium mines have been identified quantitatively based on the characteristic spectral peaks. The activity concentrations of the natural radionuclides, uranium (238U), thorium (232Th) and potassium (40K) were measured in the rock samples and radiological parameters were calculated. Uranium concentration was found to vary from 123 ± 7 Bq kg-1 to 40,858 ± 174 Bq kg-1. Activity of thorium was not significant in the samples, whereas, few samples have shown potassium activity from 162 ± 11 Bq kg-1 to 9024 ± 189 Bq kg-1. Radon exhalation rates from these samples were also measured using "Sealed Can technique" and found to vary from 4.2 ± 0.05 to 13.7 ± 0.08 Bq m-2 h-1. A positive correlation was found between the radon exhalation rate and the uranium activity. The absorbed dose rates vary from 63.6 to 18876.4 nGy h-1, with an average value of 7054.2 nGy h-1. The annual external effective dose rates vary from 0.7 to 23.2 mSv y-1. Radium equivalent activities (Raeq) varied from 134.3 to 40858.0 Bq kg-1. Value of external hazard index (Hex) varied from 0.4 to 110.4 with an average value of 41.2.

Assessment of natural radioactivity in aquifer medium bearing uranium ores in Koprubasi, Turkey

NASA Astrophysics Data System (ADS)

Simsek, Celalettin

2008-10-01

Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity levels of 226Ra, 232Th and 40K were compared with world averages. The average activity levels of 226 Ra, 232Th and 40K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13 and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have high 226Ra and 40K levels according to world average level. As these sediments are used as construction materials and in agricultural activities within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium equivalent activity (Raeq) and radiation hazard index (Iyr). All the samples have Raeq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and Iyr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high 226Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi uranium site and the environment.

Indirect spectrophotometric determination of small amounts of selenium(IV) and arsenic(V) by simple extraction using flotation columns.

PubMed

Mostafa, G A; Ghazy, S E

2001-10-01

A simple, rapid and selective procedure for the indirect spectrophotometric determination of Se(IV) and As(V) has been developed. It is based on the reduction of Se(IV) to Se(0) and As(V) to As(III) with hydroiodic acid (KI + HCl). The liberated iodine, equivalent to each analyte, is quantitatively extracted with oleic acid (HOL) surfactant. The iodine-HOL system exhibits its maximum absorbance at 435 nm. The different analytical parameters affecting the extraction and determination processes have been examined. The calibration graphs were found to be linear over the ranges 5-120 and 0.25-20 ppm of Se(IV) and As(V), with lower detection limits of 2.5 and 0.15 ppm and molar absorptivities of 1 x 10(4) and 0.5 x 10(4) dm3 mol(-1) cm(-1), respectively. Sandell's sensitivity was calculated to be 0.0078 and 0.0149 microg/cm2 in the same order. The relative standard deviation for five replicate analyses of 40 ppm Se(IV) and 4 ppm As(V) were 1.0 and 0.9%, respectively. The proposed procedure in the presence of EDTA as a masking agent for foreign ions has been successfully applied to the determination of Se(IV) in a reference sample and As(V) in copper metal, in addition to their determination in spiked and polluted water samples.

Solubility Limits of Dibutyl Phosphoric Acid in Uranium Solutions at SRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, M.C.; Pierce, R.A.; Ray, R.J.

1998-06-01

The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are {tilde 6} g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with DBP which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. SRTC tests have shown that U-DBP solids will precipitate atmore » concentrations potentially attainable during storage of enriched uranium solutions. Evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if DBP concentration in the resulting solution exceeds 110 ppm at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. The most important variables of interest for present plant operations are HNO{sub 3} and DBP concentrations. Temperature is also an important variable controlling precipitation. The data obtained in these tests can be used to set operating and safety limits for the plant. It is recommended that the data for 0 degrees C with 0.5 M HNO{sub 3} be used for setting the limits. The limit would be 80 mg/L which is 3 standard deviations below the average of 86 observed in the tests. The data shows that super-saturation can occur when the DBP concentration is as much as 50 percent above the solubility limit. However, super-saturation cannot be relied on for maintaining nuclear criticality safety. The analytical method for determining DBP concentration in U solutions was improved so that analyses for a solution are accurate to within 10 percent. However, the overall uncertainty of results for periodic samples of the existing EUS solutions was only reduced slightly. Thus, sampling appears to be the largest portion of the uncertainty for EUS sample results, although the number of samples analyzed here is low which could contribution to higher uncertainty. The analytical method can be transferred to the plant analytical labs for more routine analysis of samples.« less

Measurement of Rare Earth and Uranium Elements Using Laser-Induced Breakdown Spectroscopy (LIBS) in an Aerosol System for Nuclear Safeguards Applications

NASA Astrophysics Data System (ADS)

Williams, Ammon Ned

The primary objective of this research is to develop an applied technology and provide an assessment for remotely measuring and analyzing the real time or near real time concentrations of used nuclear fuel (UNF) elements in electroreners (ER). Here, Laser-Induced Breakdown Spectroscopy (LIBS) in UNF pyroprocessing facilities was investigated. LIBS is an elemental analysis method, which is based on the emission from plasma generated by focusing a laser beam into the medium. This technology has been reported to be applicable in solids, liquids (includes molten metals), and gases for detecting elements of special nuclear materials. The advantages of applying the technology for pyroprocessing facilities are: (i) Rapid real-time elemental analysis; (ii) Direct detection of elements and impurities in the system with low limits of detection (LOD); and (iii) Little to no sample preparation is required. One important challenge to overcome is achieving reproducible spectral data over time while being able to accurately quantify fission products, rare earth elements, and actinides in the molten salt. Another important challenge is related to the accessibility of molten salt, which is heated in a heavily insulated, remotely operated furnace in a high radiation environment within an argon gas atmosphere. This dissertation aims to address these challenges and approaches in the following phases with their highlighted outcomes: 1. Aerosol-LIBS system design and aqueous testing: An aerosol-LIBS system was designed around a Collison nebulizer and tested using deionized water with Ce, Gd, and Nd concentrations from 100 ppm to 10,000 ppm. The average %RSD values between the sample repetitions were 4.4% and 3.8% for the Ce and Gd lines, respectively. The univariate calibration curve for Ce using the peak intensities of the Ce 418.660 nm line was recommended and had an R 2 value, LOD, and RMSECV of 0.994, 189 ppm, and 390 ppm, respectively. The recommended Gd calibration curve was generated using the peak areas of the Gd 409.861 nm line and had an R2, LOD, and RMSECV of 0.992, 316 ppm, and 421 ppm, respectively. The partial least squares (PLS) calibration curves yielded similar results with RMSECV of 406 ppm and 417 ppm for the Ce and Gd curves, respectively. 2. High temperature aerosol-LIBS system design and CeCl3 testing: The aerosol-LIBS system was transitioned to a high temperature and used to measure Ce in molten LiCl-KCl salt within a glovebox environment. The concentration range studied was from 0.1 wt% to 5 wt% Ce. Normalization was necessary due to signal degradation over time; however, with the normalization the %RSD values averaged 5% for the mid and upper concentrations studied. The best univariate calibration curve was generated using the peak areas of the Ce 418.660 nm line. The LOD for this line was 148 ppm with the RMSECV of 647 ppm. The PLS calibration curve was made using 7 latent variables (LV) and resulting in the RMSECV of 622 ppm. The LOD value was below the expected rare earth concentration within the ER. 3. Aerosol-LIBS testing using UCl3: Samples containing UCl 3 with concentrations ranging from 0.3 wt% to 5 wt% were measured. The spectral response in this range was linear. The best univariate calibration curves were generated using the peak areas of the U 367.01 nm line and had an R2 value of 0.9917. Here, the LOD was 647 ppm and the RMSECV was 2,290 ppm. The PLS model was substantially better with a RMSECV of 1,110 ppm. The LOD found here is below the expected U concentrations in the ER. The successful completion of this study has demonstrated the feasibility of using an aerosol-LIBS analytical technique to measure rare earth elements and actinides in the pyroprocessing salt.

Optimized alumina coagulants for water treatment

DOEpatents

Nyman, May D [Albuquerque, NM; Stewart, Thomas A [Albuquerque, NM

2012-02-21

Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40 ppm alum, removing .about.90% of the dissolved organic material. The substituted GaAl.sub.12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO.sub.4Al.sub.12(OH).sub.24(H.sub.2O).sub.12].sup.7+.

Effect of molybdenum ion implantation of the pitting corrosion of depleted uranium - 0.75 titanium alloy. (Reannouncement with new availability information). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, K.S.; Chang, F.; Levy, M.

1993-07-01

Pitting corrosion of molybdenum-ion-implanted, depleted uranium -0 75 Ti (DU -0 75 Ti) has been studied electrochemically in acidic, neutral, and alkaline solutions containing sodium chloride, and the results have been compared to those of the unimplanted DU -0 75 Ti. The data show that Mo implantation shifts the pitting potential of DU -0 75 Ti in the noble direction in acidic and alkaline solutions. In neutral 50 ppm Cl- solution, however, there is no beneficial effect of Mo implantation. Auger analysis studies show that before exposure to the solutions, all the molybdenum is in the oxide, which is approximatelymore » l000 A thick. After electrochemical scans in the acidic and alkaline chloride solutions, most of the Mo disappears from the oxide. However, no decrease in Mo concentration is found after exposure in neutral chloride solution. It is proposed that the implanted molybdenum dissolves in the acidic and alkaline solutions and forms simple or complex molybdates that inhibit pitting corrosion. The implanted molybdenum does not dissolve in the neutral chloride solution and inhibition does not occur.« less

Quantitative ion beam analysis of M-C-O systems: application to an oxidized uranium carbide sample

NASA Astrophysics Data System (ADS)

Martin, G.; Raveu, G.; Garcia, P.; Carlot, G.; Khodja, H.; Vickridge, I.; Barthe, M. F.; Sauvage, T.

2014-04-01

A large variety of materials contain both carbon and oxygen atoms, in particular oxidized carbides, carbon alloys (as ZrC, UC, steels, etc.), and oxycarbide compounds (SiCO glasses, TiCO, etc.). Here a new ion beam analysis methodology is described which enables quantification of elemental composition and oxygen concentration profile over a few microns. It is based on two procedures. The first, relative to the experimental configuration relies on a specific detection setup which is original in that it enables the separation of the carbon and oxygen NRA signals. The second concerns the data analysis procedure i.e. the method for deriving the elemental composition from the particle energy spectrum. It is a generic algorithm and is here successfully applied to characterize an oxidized uranium carbide sample, developed as a potential fuel for generation IV nuclear reactors. Furthermore, a micro-beam was used to simultaneously determine the local elemental composition and oxygen concentration profiles over the first microns below the sample surface. This method is adapted to the determination of the composition of M?C?O? compounds with a sensitivity on elemental atomic concentrations around 1000 ppm.

Experimental study of UC polycrystals in the prospect of improving the as-fabricated sample purity

NASA Astrophysics Data System (ADS)

Raveu, Gaëlle; Martin, Guillaume; Fiquet, Olivier; Garcia, Philippe; Carlot, Gaëlle; Palancher, Hervé; Bonnin, Anne; Khodja, Hicham; Raepsaet, Caroline; Sauvage, Thierry; Barthe, Marie-France

2014-12-01

Uranium and plutonium carbides are candidate fuels for Generation IV nuclear reactors. This study is focused on the characterization of uranium monocarbide samples. The successive fabrication steps were carried out under atmospheres containing low oxygen and moisture concentrations (typically less than 100 ppm) but sample transfers occurred in air. Six samples were sliced from four pellets elaborated by carbothermic reaction under vacuum. Little presence of UC2 is expected in these samples. The α-UC2 phase was indeed detected within one of these UC samples during an XRD experiment performed with synchrotron radiation. Moreover, oxygen content at the surface of these samples was depth profiled using a recently developed nuclear reaction analysis method. Large oxygen concentrations were measured in the first micron below the sample surface and particularly in the first 100-150 nm. UC2 inclusions were found to be more oxidized than the surrounding matrix. This work points out to the fact that more care must be given at each step of UC fabrication since the material readily reacts with oxygen and moisture. A new glovebox facility using a highly purified atmosphere is currently being built in order to obtain single phase UC samples of better purity.

The effects of exercise on dose and dose distribution of inhaled automotive pollutants.

PubMed

Kleinman, M T; Mautz, W J

1991-10-01

The purpose of this study was to determine how changes in ventilation rate and in the entry route of air pollutants into the respiratory tract (nose versus mouth breathing) affected the respiratory tract uptake and penetration of inhaled gaseous and particulate pollutants associated with automobile emissions. Experiments were performed with female beagle dogs exposed while standing at rest or while exercising on a treadmill at 5 km/hour and a 7.5 percent grade. Dogs were exposed to nitrogen dioxide at concentrations of 1 and 5 parts per million (ppm), to formaldehyde at 2 and 10 ppm, and to an aerosol of ammonium nitrate particles (0.3 micron mass median aerodynamic diameter) at 1 mg/m3. Total respiratory system uptake and effects on breath time, expired tidal volume, fractional expiration time, minute ventilation, respiratory gas exchange, ventilation equivalents for oxygen and carbon dioxide, and dynamic pulmonary resistance and compliance were measured in exercising and resting dogs exposed for two hours to 5 ppm nitrogen dioxide and 10 ppm formaldehyde in combination with 1 mg/m3 of ammonium nitrate particles. Regional penetration of pollutants through oral and nasal airways and pollutant uptake in the lung were measured in a separate group of six tracheostomized dogs standing at rest while being exposed to nitrogen dioxide, formaldehyde, and ammonium nitrate particles. Hypercapnic stimulation was used to modify ventilation rates in the tracheostomized dogs while pollutant penetration and uptake were measured. Dogs exposed to 5 ppm of nitrogen dioxide at rest tended to breathe more rapidly (p less than 0.05) and more shallowly (a nonsignificant trend) than dogs exposed to purified air. The changes observed were similar in direction, but of smaller magnitude, to changes observed when the same dogs were exposed during exercise to ozone at 0.6 ppm in a separate study. Rapid-shallow breathing was not observed when the dogs were exposed during exercise to 5 ppm nitrogen dioxide. Dogs exposed to a mixture of 10 ppm formaldehyde and 1 mg/m3 ammonium nitrate particles during exercise showed a shift to larger tidal volume breathing, but the response was much less pronounced than the slow-deep breathing pattern response observed in a separate study of dogs exposed to 10 ppm formaldehyde alone. The total respiratory system uptake of formaldehyde from the formaldehyde and ammonium nitrate mixture was larger than that measured for 10 ppm of formaldehyde alone in another exercise and exposure study.(ABSTRACT TRUNCATED AT 400 WORDS)

Toxicology and carcinogenesis studies of milk thistle extract (CAS No. 84604-20-6) in F344/N rats and B6C3F1 mice (Feed Studies).

PubMed

2011-05-01

Milk thistle extracts have been used as medicinal herbs in the treatment of liver cirrhosis, chronic hepatitis (liver inflammation), and gallbladder disorders. Treatment claims also include lowering cholesterol levels; reducing insulin resistance; reducing the growth of cancer cells in breast, cervical, and prostate gland cancers; and antiviral activity. Other reported uses of milk thistle in folk medicine include as a treatment for malarial fever, bronchitis, gallstones, jaundice, peritonitis, uterine congestion, varicose veins, and as a milk production stimulant for nursing mothers. The roots soaked in water overnight are used in food, and the despined leaves are added to salads. Roasted milk thistle fruit has been used as a coffee substitute. Milk thistle extract was nominated for study by the National Institute of Environmental Health Sciences because it is one of the most widely used herbs in the United States. Male and female F344/N rats and B6C3F1 mice were exposed to an ethanol/water extract of milk thistle fruit (milk thistle extract) containing approximately 65% silymarin in feed for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and Escherichia coli and mouse peripheral blood erythrocytes. 3-MONTH STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets containing 0, 3,125, 6,250, 12,500, 25,000, or 50,000 ppm milk thistle extract (equivalent to average daily doses of approximately 260, 525, 1,050, 2,180, or 4,500 mg milk thistle extract/kilogram body weight to males and 260, 510, 1,050, 2,150, or 4,550 mg/kg to females) for 14 weeks. All rats survived to the end of the study. Mean body weights of exposed groups were within 10% of those of the controls. Feed consumption by exposed and control groups was similar. The sperm motility in 12,500, 25,000, and 50,000 ppm males was decreased by 5%, 11%, and 9%, respectively, relative to that of the controls; the total number of spermatid heads per testis decreased by 11%, 21%, and 9% in 12,500, 25,000, and 50,000 ppm males. No significant differences in estrous cyclicity were observed between exposed and control groups of female rats. No exposure-related histopathologic lesions were observed. 3-MONTH STUDY IN MICE: Groups of 10 male and 10 female mice were fed diets containing 0, 3,125, 6,250, 12,500, 25,000, or 50,000 ppm milk thistle extract (equivalent to average daily doses of approximately 640, 1,340, 2,500, 5,280, or 11,620 mg/kg to males and 580, 1,180, 2,335, 4,800, or 9,680 mg/kg to females) for 14 weeks. All mice survived to the end of the study. Mean body weights and feed consumption of all exposed groups were similar to those of the controls. Absolute and relative thymus weights were significantly decreased in 25,000 and 50,000 ppm males. No significant differences were observed between exposed and control groups, for sperm parameters of male mice, for estrous cyclicity of female mice, or for reproductive organ weights of male or female mice, when mice were administered milk thistle extract in feed at 12,500, 25,000, or 50,000 ppm. No exposure-related histopathologic lesions were observed. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were fed diets containing 0, 12,500, 25,000, or 50,000 ppm milk thistle extract (equivalent to average daily doses of approximately 570, 1,180, or 2,520 mg/kg to males and 630, 1,300, or 2,750 mg/kg to females) for 105 to 106 weeks. Exposure to milk thistle extract had no effect on survival of male or female rats. Mean body weights of all exposed groups were similar to those of the controls throughout the study. Feed consumption by exposed groups of males and females was generally similar to that by the controls throughout the study. Significantly decreased incidences of mammary gland fibroadenoma, adenoma, or carcinoma (combined) occurred in females exposed to 25,000 or 50,000 ppm. Significantly increased incidences of clear cell and mixed cell focus of the liver occurred in 25,000 and 50,000 ppm females. The incidences of bile duct hyperplasia were significantly decreased in 50,000 ppm males and in all exposed groups of females, and the incidence of mixed inflammatory cell infiltration was significantly decreased in 50,000 ppm males. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were fed diets containing 0, 12,500, 25,000, or 50,000 ppm milk thistle extract (equivalent to average daily doses of approximately 1,610, 3,530, or 7,770 mg/kg to males and 1,500, 3,175, or 7,180 mg/kg to females) for 105 to 106 weeks. Exposure to milk thistle extract had no effect on survival of male or female mice. The mean body weights of the 25,000 ppm groups were less than those of controls after week 25; mean body weights of 50,000 ppm groups were less than those of controls after week 12. Feed consumption by exposed groups of males and females was generally similar to that by the controls throughout the study. Significantly decreased incidences of hepatocellular adenoma and hepatocellular carcinoma occurred in 50,000 ppm males, and decreased incidences of hepatocellular adenoma or carcinoma (combined) occurred in 25,000 and 50,000 ppm males. Five milk thistle extracts were tested independently in bacterial mutagenicity studies using a variety of S. typhimurium tester strains and one E. coli strain. Results were negative in three of the five studies, with and without exogenous metabolic activation. In two studies, milk thistle extract was mutagenic in S. typhimurium strain TA98 in the presence of exogenous metabolic activation enzymes. Silymarin, a major constituent of milk thistle extract, was positive in S. typhimurium strains TA98 and TA100, when testing occurred in the presence of exogenous metabolic activation enzymes. Silybin, another component of milk thistle extract, was negative in a S. typhimurium gene mutation assay, with and without liver S9 activation enzymes. Administration of milk thistle extract in feed for 3 months did not increase the frequencies of micronucleated normochromatic erythrocytes, an indication of chromosomal abnormalities, in the peripheral blood of male or female B6C3F1 mice. Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of milk thistle extract in male or female F344/N rats or B6C3F1 mice exposed to 12,500, 25,000, or 50,000 ppm. Exposure to milk thistle extract resulted in increased incidences of clear cell and mixed cell foci in the liver of female rats and decreases in body weights of exposed groups of male and female mice. Decreased incidences of mammary gland neoplasms occurred in exposed groups of female rats, and decreased incidences of hepatocellular neoplasms occurred in exposed groups of male mice.

Impact of uranium mining activity on cave deposit (stalagmite) and pine trees (S-Hungary)

NASA Astrophysics Data System (ADS)

Siklosy, Z.; Kern, Z.; Demeny, A.; Pilet, S.; Leel-Ossy, Sz.; Lin, K.; Shen, C.-C.; Szeles, E.

2009-04-01

Speleothems are well known paleoclimate archives but their potential for monitoring environmental pollution has not been fully explored. This study deals with an actively growing stalagmite whose trace-element concentration suggests anthropogenic contamination, rather then natural forcing. Paralell, as a potential independent chemo-enviromental archive, living pine (Pinus sylvestis) trees were also involved into investigation. U production in S-Hungary started in 1957 and was expanded closer to the cave site in 1965, covering a mining plot area of ca. 65 km2. The deep-level ore production ended in 1997 and remediation of the mine site has since been completed. Our objective was to determine the possible effect of the four-decade-long uranium (U) ore mining activity on the environment, as recorded by a cave deposit and the pine trees. The Trio Cave is located in the Mecsek Mts (S-Hungary), ca. 1.5-3 km east from the nearest air-shaft and entrance of the uranium mine. A stalagmite located about 150 m away from the cave entrance was drilled and the core investigated for stable isotope and trace element compositions. Pine trees were sampled by increment borer. Continuous flow mass spectrometry was applied on carbonate samples and laser ablation ICP-MS was applied for trace element analysis of both stalagmite (Siklosy et al., 2009) and pine samples. The youngest 1 cm of the drill core was selected for this study that may represent the last cca. 100 years (based on MC-ICP-MS age dating of older parts of the core) that covers the uranium mining period. The pre-mining period is characterized by systematic co-variations of trace elements (U, P, Si, Al, Ba, Mg, etc.) that can be related to soil activity and precipitation amount. The youngest 1.3 mm, however, records a sudden change in U content uncorrelated with any other variables. Starting from a background value of 0.2-0.3 ppm, the concentration gradually increases to about 2 ppm (within about 1 mm), remains constant for about 0.5 mm, then declines to about 1.5 ppm at the surface. The increase in U concentration coincided with a significant decrease in d234U initial values (Siklosy et al., 2008) suggesting contribution from a U source different from the natural weathering input. This is also supported by a change in the P/U ratio and much weaker correlation of the U concentrations with P in the U-enriched section of the stalagmite ("mining-period"). According to the average growth rate of the stalagmite, this period represents the last 30-50 years. Dendrochemical data covered the 1914-2004 period. The trace element time series derived from tree rings are characterized by plateaux-like maxima during the late-1960s and the 1985-95 period. This elevated events closely coupled to opening of two different uranium mine pits. Two prominent peaks emerged in the U-record coinciding the 1968 and 1991 tree rings. Dendrochemical data show abrupt increase in trace elemets (most pronounced in metals) from the tree ring dated to 1966 while the sudden decrease positioned to 1998 tree-ring. The perfect agreement between the dendrochronological dates of major changes in the chemistry of the wood and the onset-offset dates of mining history gives high probability that the mining activity is the main agent responsible for this environmental change. The possible source of U is therefore the 40-year-old Mecsek uranium mine, which produced ca. 500 tons of U concentrate per year and has reworked millions of tons of solid material (Bánik et al., 2002). Acknowledgements — This study was financially supported by the Hungarian Scientific Research Fund (OTKA T 049713 and K 67583). Measurements of U-Th isotopic compositions and and 230Th dates were supported by the National Science Council grants (94-2116-M002-012, 97-2752-M002-004-PAE & -005-PAE to C.C.S.). Bánik, J., Csicsák, J. and Berta, Zs. 2002: Experience on application of continuous drain trench during the remediation of tailings ponds in Hungary. In: Broder J. M., et al. (Eds), Uranium Mining and Hydrogeology III, 913-921. Siklósy, Z., Demény, A.,Pilet, S., Leél-Ossy, Lin, K. and Shen, C-C. 2008: Monitoring environmental pollution using a stalagmite from Hungary. PAGES News 16/3. 27-28. Siklósy, Z., Demény, A., Vennemann, T.W., Pilet, S., Kramers, J., Leél-Ossy, Sz., Bondár, M., Shen, C-C. and Hegner, E. 2009: Bronze Age volcanic event recorded in stalagmites by combined isotope and trace element studies, Rapid Communications in Mass Spectrometry, Accepted for publ.

Analysis Of 2H-Evaporator Scale Wall [HTF-13-82] And Pot Bottom [HTF-13-77] Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.

2013-09-11

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material has been performed so that uranium and plutonium isotopic analysis can be input into a Nuclear Criticality Safety Assessment (NCSA) for scale removal by chemical cleaning. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporatormore » pot and gravity drain line. The 2H-evaporator scale samples analyzed by Savannah River National Laboratory (SRNL) came from two different locations within the evaporator pot; the bottom cone sections of the 2H-evaporator pot [Sample HTF-13-77] and the wall 2H-evaporator [sample HTF-13-82]. X-ray diffraction analysis (XRD) confirmed that both the 2H-evaporator pot scale and the wall samples consist of nitrated cancrinite (a crystalline sodium aluminosilicate solid) and clarkeite (a uranium oxyhydroxide mineral). On ''as received'' basis, the bottom pot section scale sample contained an average of 2.59E+00 {+-} 1.40E-01 wt % total uranium with a U-235 enrichment of 6.12E-01 {+-} 1.48E-02 %, while the wall sample contained an average of 4.03E+00 {+-} 9.79E-01 wt % total uranium with a U-235 enrichment of 6.03E-01% {+-} 1.66E-02 wt %. The bottom pot section scale sample analyses results for Pu-238, Pu-239, and Pu-241 are 3.16E-05 {+-} 5.40E-06 wt %, 3.28E-04 {+-} 1.45E-05 wt %, and <8.80E-07 wt %, respectively. The evaporator wall scale samples analysis values for Pu-238, Pu-239, and Pu-241 averages 3.74E-05 {+-} 6.01E-06 wt %, 4.38E-04 {+-} 5.08E-05 wt %, and <1.38E-06 wt %, respectively. The Pu-241 analyses results, as presented, are upper limit values. For these two evaporator scale samples obtained at two different locations within the evaporator pot the major radioactive components (on a mass basis) in the additional radionuclide analyses were Sr-90, Cs-137 Np-237, Pu-239/240 and Th-232. Small quantities of americium and curium were detected in the blanks used for Am/Cm method for these radionuclides. These trace radionuclide amounts are assumed to come from airborne contamination in the shielded cells drying or digestion oven, which has been replaced. Therefore, the Am/Cm results, as presented, may be higher than the true Am/Cm values for these samples. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241. The applicable method for calculation of equivalent U-235 will be determined in the NCSA. With a few exceptions, a comparison of select radionuclides measurements from this 2013 2H evaporator scale characterization (pot bottom and wall scale samples) with those measurements for the same radionuclides in the 2010 2H evaporator scale analysis shows that the radionuclide analysis for both years are fairly comparable; the analyses results are about the same order of magnitude.« less

Reconnaissance of radioactive rocks of Maine

USGS Publications Warehouse

Nelson, John M.; Narten, Perry F.

1951-01-01

The state of Maine was traversed with car-mounted Geiger-Mueller equipment in the late summer of 1948 and the radioactivity of approximately 4,600 miles of road was logged. All samples were analyzed, both in the field by comparing the radioactivity of each sample to the radioactivity of a stranded measured with a simple scaling modification of a portable counter, and in the Geological Survey’s Trace Elements Section Washington Laboratory. Differences between both types of analyses were negligible. The maximum equivalent uranium content of the most radioactive rocks thus analyzed was 0.008 percent. A 1,400-square-mile abnormally radioactive province in southwestern Maine was outlined. The outcrop data obtained from car traversing are evaluated statistically. Cumulative frequency distribution curves are drawn to show the distribution of outcrops at various levels of radioactivity, and straight-line extensions are made to show to maximum probable grade for various rock types and areas in Maine. A maximum grade of 0.055 percent equivalent uranium is thus predicted for the entire state. This prediction necessarily is a broad generalization because large areas of Main are inaccessible for car traversing. A concept of evaluation of an area for possible mineral deposits is proposed on the basis of lithology, and observed and indicated ranges in grade.

Toxicology and carcinogenesis study of styrene-acrylonitrile trimer in F344/N rats (perinatal and postnatal feed studies).

PubMed

2012-07-01

Styrene-acrylonitrile trimer (SAN Trimer) is a mixture of isomers formed by the condensation of two moles of acrylonitrile and one mole of styrene and has a molecular weight of 210. The mixture is composed of two structural forms: 4-cyano-1,2,3,4-tetrahydro-a-methyl-1-naphthaleneacetonitrile (THNA, CAS No. 57964-39-3) and 4-cyano-1,2,3,4-tetrahydro-1-naphthalenepropionitrile (THNP, CAS No. 57964-40-6). The THNA form consists of four stereoisomers. [Structure:see text]. The THNP form consists of two stereoisomers. [Structure:see text]. SAN Trimer is a by-product of the production of acrylonitrile styrene plastics and is created in specific manufacturing processes for polymers of acrylonitrile and styrene. In June 1998, due to community concerns about the toxicity of SAN Trimer, it was nominated to the NTP for carcinogenicity testing by a member of Congress. Male and female F344/N rats were exposed to SAN Trimer in feed in perinatal and postnatal studies for 7 weeks, 18 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and Escherichia coli, and in rat reticulocytes, leukocytes, liver cells, and brain cells. In vivo comet and micronucleus assays were performed in the juvenile rats. 7-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets containing 0, 250, 500, 1,000, 2,000, or 4,000 ppm SAN Trimer (equivalent to average daily doses of approximately 50, 90, 175, 270, or 410 mg SAN Trimer/kg body weight to males and 45, 90, 185, 295, or 430 mg/kg to females) for 2 weeks postweaning; the dams of these rats were fed the same concentrations of SAN Trimer from gestation day 7 until the pups were weaned. One 4,000 ppm male rat died 3 days after weaning; all other rats that started the postweaning phase survived to the end of the study. Mean body weights of 1,000, 2,000, and 4,000 ppm males and 2,000 and 4,000 ppm females were significantly less than those of the controls; weaning mean body weights were reduced in 4,000 ppm males and females and in 2,000 ppm females. Feed consumption by 2,000 and 4,000 ppm males and females was less than that by the control groups. Thinness in 4,000 ppm male rats was the only clinical finding related to SAN Trimer exposure. Nonneoplastic lesions were observed in the brain, thymus, spleen, liver, kidney, and reproductive organs of males and females and were considered due to overt toxicity. 18-WEEK STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets of 0, 100, 200, 400, 800, or 1,600 ppm SAN Trimer (equivalent to average daily doses of 10, 20, 40, 80, or 150 mg/kg to males and females) for 3 months postweaning; the dams of these rats were fed the same concentrations from gestation day 7 until the pups were weaned. All rats survived to the end of the study. Mean body weights of 1,600 ppm males and females exposed to 200 ppm or greater were significantly less than those of the controls. At termination, brown staining of the urogenital fur was observed in females exposed to 200 ppm or greater. The liver weights of all exposed groups of males and the spleen weights of 800 and 1,600 ppm males and 1,600 ppm females were significantly greater than those of the controls. There were no significant differences in sperm parameters of male rats or the estrous cyclicity of female rats administered 400, 800, or 1,600 ppm in the diet when compared to the control groups. No exposure-related histopathologic lesions were observed. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female core study rats were fed diets of 0, 400, 800, or 1,600 ppm SAN Trimer (equivalent to average daily doses of approximately 20, 40, or 75 mg/kg to males and 20, 40, or 85 mg/kg to females) for 2 years. Special study groups of 20 males and 20 females were fed the same exposure concentrations and were evaluated at 27, 52, and 78 weeks for hematology and clinical chemistry or at 26, 51, and 77 weeks for urinalysis. The dams of core and special study rats were fed the same concentrations from gestation day 7 until the pups were weaned. Mean body weights of 1,600 ppm males were less than 90% of the controls after week 1; mean body weights of 800 and 1,600 ppm females were less than 90% of the controls after weeks 41 and 13, respectively. Feed consumption by exposed groups of males and females was generally similar to that by the control groups. Brown staining of the urogenital fur was observed in all exposed groups, and the number of animals affected increased with increasing exposure concentration. Rare neoplasms were present in the central nervous system of male and female rats. In the original evaluation, the 800 and 1,600 ppm groups of male rats each had one astrocytoma and one granular cell tumor in the brain. Also in the brain, one 400 ppm female had a granular cell tumor and one control, one 400 ppm, and one 800 ppm female had a mixed cell glioma. In the spinal cord, one astrocytoma was noted in a 1,600 ppm male in the original evaluation. In the expanded review of the spinal cord, one granular cell tumor was found in a 400 ppm male and one meningioma was found in an 800 ppm female. There were statistically significant increases in the incidence of spinal nerve root degeneration in 1,600 ppm males and the incidences of sciatic nerve degeneration in 800 and 1,600 ppm females. More importantly, there were increases in the severities of both nerve lesions in males and in the severity of spinal nerve root degeneration in females. The incidences of bone marrow hyperplasia were significantly increased in 1,600 ppm males and females and 800 ppm females. Incidences of bone marrow granulomatous inflammation were increased in 1,600 ppm males and 800 and 1,600 ppm females, and the increase in the 800 ppm females was significant. Because this lesion is very rare and did not occur in control animals, it should be considered biologically significant. In the liver, the incidence of eosinophilic focus was significantly increased in 1,600 ppm males and the incidences of mixed cell focus were significantly increased in 400 and 1,600 ppm males. Incidences of mixed cell focus were increased in the liver of all exposed groups of females, and the increase was significant in the 1,600 ppm group. The incidence of transitional epithelial hyperplasia of the urinary bladder in 1,600 ppm females was significantly greater than that in the controls. There were significant decreases in the incidences of pituitary gland pars distalis adenoma in 1,600 ppm males and females, and the incidences in both sexes occurred with negative trends. The incidences of mammary gland fibroadenoma occurred in females with a negative trend, and the incidences in 800 and 1,600 ppm females were significantly less than that in the control group. The incidences of mononuclear cell leukemia in all exposed groups of males and females were significantly less than those in the controls. SAN Trimer (Batch 3) was not mutagenic in Salmonella typhimurium strains TA98 or TA100 or in Escherichia coli strain WP2 uvrA/pKM101 in tests conducted with and without exogenous metabolic activation. In vivo, however, results of a comet assay indicated significantly increased levels of DNA damage in brain cells of male and female juvenile rats following administration of SAN Trimer (Batch 3) by oral gavage. Dose-related increases in DNA damage in liver cells of these rats were also observed, but the increases were smaller than those observed in brain cells and were judged to be equivocal in both males and females. Indications of DNA damage following exposure to SAN Trimer were also seen in leukocytes of male and female rats. Increases in male rats were significant, but in females, observed levels of DNA damage did not correlate with dose. Therefore, the results were judged to be positive in males and equivocal in females. In addition to the positive comet assay results, significant increases in the frequencies of micronucleated reticulocytes were observed in peripheral blood of male and female juvenile rats dosed with SAN Trimer. Under the conditions of this 2-year feed study preceded by perinatal exposure, there was no evidence of carcinogenic activity of SAN Trimer in male and female F344/N rats given feed containing 400, 800, or 1,600 ppm SAN Trimer. Exposure to SAN Trimer resulted in increased incidences and/or severities of peripheral nerve degeneration in male and female F344/N rats, increased incidences of nonneoplastic lesions of the bone marrow and liver in male and female F344/N rats, and of nonneoplastic urinary bladder lesions in female F344/N rats. The incidences of pituitary gland adenoma and mononuclear cell leukemia in male and female F344/N rats and mammary gland fibroadenoma in female F344/N rats were decreased.

Programing Procedures Manual (PPM).

DTIC Science & Technology

1981-12-15

terms ’reel’, ’unit’, and ’volume’ are synonymous and completely interchangeable in the CLOSE statement. Treatment of sequential mass storage files is...logically equivalent to the treatment of a file on tape or analogous sequential media. * For the purpose of showing the effect of various types of CLOSE...Overlay Area CA6 Address of Abend Relative to beginning of overlay segment The programer can now refer to the compile source listing for the overlay

Solid oxide fuel cell anode degradation by the effect of hydrogen chloride in stack and single cell environments

NASA Astrophysics Data System (ADS)

Madi, Hossein; Lanzini, Andrea; Papurello, Davide; Diethelm, Stefan; Ludwig, Christian; Santarelli, Massimo; Van herle, Jan

2016-09-01

The poisoning effect by hydrogen chloride (HCl) on state-of-the-art Ni anode-supported solid oxide fuel cells (SOFCs) at 750 °C is evaluated in either hydrogen or syngas fuel. Experiments are performed on single cells and short stacks and HCl concentration in the fuel gas is increased from 1 ppm(v) up to 1000 ppm(v) at different current densities. Characterization methods such as cell voltage monitoring vs. time and electrochemical impedance response analysis (distribution of relaxation times (DRT), equivalent electrical circuit) are used to identify the prevailing degradation mechanism. Single cell experiments revealed that the poisoning is more severe when feeding with hydrogen than with syngas. Performance loss is attributed to the effects of HCl adsorption onto nickel surfaces, which lowered the catalyst activity. Interestingly, in syngas HCl does not affect stack performance even at concentrations up to 500 ppm(v), even when causing severe corrosion of the anode exhaust pipe. Furthermore, post-test analysis suggests that chlorine is present on the nickel particles in the form of adsorbed chlorine, rather than forming a secondary phase of nickel chlorine.

Microbial destruction by low concentrations of hypochlorite and iodophor germicides in alkaline and acidified water.

PubMed

Hays, H; Elliker, P R; Sandine, W E

1967-05-01

Hypochlorite and iodophor germicides were evaluated for their ability to destroy a variety of organisms at levels approximating those used for final sanitizing rinse for dairy and food equipment and beverage bottles (3 to 50 ppm). Test organisms included Escherichia coli, Streptococcus lactis, Lactobacillus plantarum, Pediococcus cerevisiae, and Saccharomyces cerevisiae. The hypochlorites and iodophors demonstrated approximate rates of destruction at equivalent concentrations for the bacterial species tested, except where the hypochlorite contained excess alkalinity. The hypochlorite responded more readily to a downward shift to a pH of 5.0 than did the iodophor. Excess alkalinity of the hypochlorite significantly affected its bactericidal activity. The iodophor exhibited a consistently greater rate of destruction of yeast cells than the hypochlorite. Successive treatment with low levels of iodophor (6 ppm) followed by a hypochlorite (12 to 25 ppm) resulted in a high level of destruction of all test organisms. Possibilities for employing these measures in a sanitizing rinse of bottles for maximal destruction of organisms were discussed. Among the test organisms, S. lactis showed a comparatively high resistance and was a useful organism for comparing the halogen preparations.

75 FR 22895 - Control of Emissions From New Marine Compression-Ignition Engines at or Above 30 Liters per Cylinder

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

...EPA is finalizing emission standards for new marine diesel engines with per-cylinder displacement at or above 30 liters (called Category 3 marine diesel engines) installed on U.S. vessels. These emission standards are equivalent to those adopted in the amendments to Annex VI to the International Convention for the Prevention of Pollution from Ships (MARPOL Annex VI). The emission standards apply in two stages--near-term standards for newly built engines will apply beginning in 2011; long-term standards requiring an 80 percent reduction in NOX emissions will begin in 2016. We are also finalizing a change to our diesel fuel program that will allow for the production and sale of 1,000 ppm sulfur fuel for use in Category 3 marine vessels. In addition, the new fuel requirements will generally forbid the production and sale of other fuels above 1,000 ppm sulfur for use in most U.S. waters, unless alternative devices, procedures, or compliance methods are used to achieve equivalent emissions reductions. We are adopting further provisions under the Act to Prevent Pollution from Ships, especially to apply the emission standards to engines covered by MARPOL Annex VI that are not covered by the Clean Air Act, and to require that these additional engines use the specified fuels (or equivalents). The final regulations also include technical amendments to our motor vehicle and nonroad engine regulations; many of these changes involve minor adjustments or corrections to our recently finalized rule for new nonroad spark-ignition engines, or adjustment to other regulatory provisions to align with this recent final rule.

Increasing the Accuracy in the Measurement of the Minor Isotopes of Uranium: Care in Selection of Reference Materials, Baselines and Detector Calibration

NASA Astrophysics Data System (ADS)

Poths, J.; Koepf, A.; Boulyga, S. F.

2008-12-01

The minor isotopes of uranium (U-233, U-234, U-236) are increasingly useful for tracing a variety of processes: movement of anthropogenic nuclides in the environment (ref 1), sources of uranium ores (ref 2), and nuclear material attribution (ref 3). We report on improved accuracy for U-234/238 and U-236/238 by supplementing total evaporation protocol TIMS measurement on Faraday detectors (ref 4)with multiplier measurement for the minor isotopes. Measurement of small signals on Faraday detectors alone is limited by noise floors of the amplifiers and accurate measurement of the baseline offsets. The combined detector approach improves the reproducibility to better than ±1% (relative) for the U-234/238 at natural abundance, and yields a detection limit for U-236/U-238 of <0.2 ppm. We have quantified contribution of different factors to the uncertainties associated with these peak jumping measurement on a single detector, with an aim of further improvement. The uncertainties in the certified values for U-234 and U-236 in the uranium standard NBS U005, if used for mass bias correction, dominates the uncertainty in their isotopic ratio measurements. Software limitations in baseline measurement drives the detection limit for the U-236/U-238 ratio. This is a topic for discussion with the instrument manufacturers. Finally, deviation from linearity of the response of the electron multiplier with count rate limits the accuracy and reproducibility of these minor isotope measurements. References: (1) P. Steier et al(2008) Nuc Inst Meth(B), 266, 2246-2250. (2) E. Keegan et al (2008) Appl Geochem 23, 765-777. (3) K. Mayer et al (1998) IAEA-CN-98/11, in Advances in Destructive and Non-destructive Analysis for Environmental Monitoring and Nuclear Forensics. (4) S. Richter and S. Goldberg(2003) Int J Mass Spectrom, 229, 181-197.

PROPERTIES OF URANIUM MONOCARBIDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, D.J.; Stobo, J.J.

1963-02-01

Some of the properties of UC relevant to its use as a fuel for either thermal or fast reactors were evaluated. The oxidation resistance of cast UC is shown to be superior to that of U metal above about 550 deg C in CO/sub 2/, and above about 200 deg C in air containing 1 wt% H/sub 2/O. In CO/sub 2/ at 800 deg C, even porous sintered UC is more resistant than U. Good compatibility with liquid Na (containing 10 ppm O) is reported, after 8 weeks at 800 and at 750 deg C. Hot-hardness values drop from 700more » VPN at 300 deg C to 50 VPN at 1000 deg C. (auth)« less

Spectral gamma-ray evaluation of Lower Jurassic basalts and lacustrine sediments from the Fundy Basin (Nova Scotia, Canada)

NASA Astrophysics Data System (ADS)

Silva, Ricardo L.; Wach, Grant; Wong, Carlos

2014-05-01

In the Fundy Basin (Nova Scotia, Canada), the McCoy Brook Formation corresponds to the first sedimentary unit of Early Jurassic (Hettangian-Pliensbachian) age deposited after the North Mountain basalts, part of the Central Atlantic Magmatic Province (CAMP). The McCoy Brook Formation includes at its base the Scots Bay Member, comprising red and green lutites, silicified limestones, cherts, stromatolites and sandstones. Deposition of the Scots Bay Member occurred in a shallow and oxygenated lake, where the trophic state varied from oligotrophic to eutrophic. The McCoy Brook Formation is less than 100ky younger than the end-Triassic extinction event (Olsen and Et-Touhami, 2008 and references therein). We analysed the spectral gamma-ray (GR) response of the top of the North Mountain basalts and base of the Scots Bay member at Broad Cove (Kings County, Nova Scotia, Canada) in order to calibrate outcrop with borehole wireline data and test uranium as a proxy for organic matter richness. The North Mountain basalts have a constant and low GR profile, varying from 58-92 cts. Potassium varies from 0.5-1.3%, U from 0-3.1ppm and Th from 0-5.1ppm. Average content of these elements are 1.0 %, 1.9ppm and 2.5ppm, respectively. The Scots Bay Member presents more variation, from 162 cts at the base to 68 cts at the top. Potassium varies from 0.4-2.3%, U from 0-6.4ppm and Th from 0-10.0ppm. Average content of these elements are 1.2%, 3.4ppm and 4.1ppm, respectively. The use of U contents to estimate TOC (see for example, Correia et al., 2012) generates non-significant results, where limestones have TOC of 11wt%. Olsen and Et-Touhami (2008) report that these outcrops are organically lean, with TOC lower that 1wt%. It is apparent that the high U contents and the overestimation of authigenic U is linked with U mineralization due the stromatolites and microbial activity, highlighting that lithological and mineralogical components are critical to accurate petrophysical interpretation of borehole wireline data through the studied time interval. We acknowledge ExxonMobil Canada Proprieties, on behalf of the Sable Offshore Energy Project, for financial support of through the Petroleum Geoscience Research Grant to Dalhousie University (Basin and Reservoir Lab). Correia GG, Duarte LV, Pereira A, Silva RL (2012) Outcrop gamma-ray spectrometry: Applications to the Sinemurian-Pliensbachian organic-rich facies of the Lusitanian Basin (Portugal). Journal of Iberian Geology, 38, 373-388 Olsen PE and Et-Touhami M (2008) Field Trip #1: Tropical to subtropical syntectonic sedimentation in the Permian to Jurassic Fundy rift basin, Atlantic Canada, in relation to the Moroccan conjugate margin. Central Atlantic Conjugate Margins Conference Halifax, 121 pp.

The study of in vivo quantification of aluminum (Al) in human bone with a compact DD generator-based neutron activation analysis (NAA) system.

PubMed

Byrne, Patrick; Mostafaei, Farshad; Liu, Yingzi; Blake, Scott P; Koltick, David; Nie, Linda H

2016-05-01

The feasibility and methodology of using a compact DD generator-based neutron activation analysis system to measure aluminum in hand bone has been investigated. Monte Carlo simulations were used to simulate the moderator, reflector, and shielding assembly and to estimate the radiation dose. A high purity germanium (HPGe) detector was used to detect the Al gamma ray signals. The minimum detectable limit (MDL) was found to be 11.13 μg g(-1) dry bone (ppm). An additional HPGe detector would improve the MDL by a factor of 1.4, to 7.9 ppm. The equivalent dose delivered to the irradiated hand was calculated by Monte Carlo to be 11.9 mSv. In vivo bone aluminum measurement with the DD generator was found to be feasible among general population with an acceptable dose to the subject.

PPM/NAR 8.4-GHz noise temperature statistics for DSN 64-meter antennas, 1982-1984

NASA Technical Reports Server (NTRS)

Slobin, S. D.; Andres, E. M.

1986-01-01

From August 1982 through November 1984, X-band downlink (8.4-GHz) system noise temperature measurements were made on the DSN 64-m antennas during tracking periods. Statistics of these noise temperature values are needed by the DSN and by spacecraft mission planners to assess antenna, receiving, and telemetry system needs, present performance, and future performance. These measurements were made using the DSN Mark III precision power monitor noise-adding radiometers located at each station. It is found that for DSS 43 and DSS 63, at the 90% cumulative distribution level, equivalent zenith noise temperature values fall between those presented in the earlier (1977) and present (1983) versions of DSN/Flight Project design documents. Noise temperatures measured for DSS 14 (Goldstone) are higher than those given in existing design documents and this disagreement will be investigated as a diagnostic of possible PPM or receiving system performance problems.

Increased Multilayer Fabrication and RF Characterization of a High-Density Stacked MIM Capacitor Based on Selective Etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tseng, VFG; Xie, HK

2014-07-01

This paper presents the fabrication and characterization of a high-density multilayer stacked metal-insulator-metal (MIM) capacitor based on a novel process of depositing the MIM multilayer on pillars followed by polishing and selective etching steps to form a stacked capacitor with merely three photolithography steps. In this paper, the pillars were made of glass to prevent substrate loss, whereas an oxide-nitride-oxide dielectric was employed for lower leakage, better voltage/frequency linearity, and better stress compensation. MIM capacitors with six dielectric layers were successfully fabricated, yielding capacitance density of 3.8 fF/mu m(2), maximum capacitance of 2.47 nF, and linear and quadratic voltage coefficientsmore » of capacitance below 21.2 ppm/V and 2.31 ppm/V-2. The impedance was measured from 40 Hz to 3 GHz, and characterized by an analytically derived equivalent circuit model to verify the radio frequency applicability. The multilayer stacking-induced plate resistance mismatch and its effect on the equivalent series resistance (ESR) and effective capacitance was also investigated, which can be counteracted by a corrected metal thickness design. A low ESR of 800 m Omega was achieved, whereas the self-resonance frequency was >760 MHz, successfully demonstrating the feasibility of this method to scale up capacitance densities for high-quality-factor, high-frequency, and large-value MIM capacitors.« less

Hydrothermal barite mineralization at Chenarvardeh deposit, Markazi Province, Iran: Evidences from REE geochemistry and fluid inclusions

NASA Astrophysics Data System (ADS)

Ehya, Farhad; Mazraei, Shaghayegh Moalaye

2017-10-01

Barite mineralization occurs at Chenarvardeh deposit as layers and lenses in Upper Eocene volcanic and pyroclastic rocks. The host rocks are intensely saussuritized in most places. Barite is accompanied by calcite, Mn-oxides, galena and malachite as subordinate minerals. The amount of Sr in barites is low and varies between 0.11 and 0.30 wt%. The concentration of Rb, Zr, Y, Ta and Hf is also low (<5 ppm) in barite samples. The amount of total REEs (∑REE) is low in barites, ranging from 7.51 to 30.50 ppm. Chondrite-normalized REE patterns reveal LREE enrichment with respect to HREE, and positive Ce anomalies. Fluid inclusions are common in barite samples, being dominantly from liquid-rich two phase (L + V) type. Salinity values in fluid inclusions range from 9.41 to 18.69 wt% NaCl equivalent with most frequent salinities falling in the range of 10-15 wt% NaCl equivalent. Homogenization temperatures (Th) range between 160 and 220 °C, being the 180-200 °C range as the most common Th interval. A combination of factors, including geologic setting, host rock, mineral assemblages, REE geochemistry and fluid inclusion data are consistent with a submarine volcanic hydrothermal model for barite formation at the Chenarvardeh deposit. Mineral-forming fluids originated from solutions related to submarine hydrothermal activities deposited barite on seafloor as they encountered sulfate-bearing seawater.

Oil Spill Field Trial at Sea: Measurements of Benzene Exposure.

PubMed

Gjesteland, Ingrid; Hollund, Bjørg Eli; Kirkeleit, Jorunn; Daling, Per; Bråtveit, Magne

2017-07-01

Characterize personal exposure to airborne hydrocarbons, particularly carcinogenic benzene, during spill of two different fresh crude oils at sea. The study included 22 participants taking part in an «oil on water» field trial in the North Sea. Two types of fresh crude oils (light and heavy) were released six times over two consecutive days followed by different oil spill response methods. The participants were distributed on five boats; three open sampling boats (A, B, and C), one release ship (RS), and one oil recovery (OR) vessel. Assumed personal exposure was assessed a priori, assuming high exposure downwind and close to the oil slick (sampling boats), low exposure further downwind (100-200 m) and upwind from the oil slick (main deck of RS and OR vessel), and background exposure indoors (bridge of RS/OR vessel). Continuous measurements of total volatile organic compounds in isobutylene equivalents were performed with photoionization detectors placed in all five boats. Full-shift personal exposure to benzene, toluene, ethylbenzene, xylenes, naphthalene, and n-hexane was measured with passive thermal desorption tubes. Personal measurements of benzene, averaged over the respective sample duration, on Day 1 showed that participants in the sampling boats (A, B, and C) located downwind and close to the oil slick were highest exposed (0.14-0.59 ppm), followed by participants on the RS main deck (0.02-0.10 ppm) and on the bridge (0.004-0.03 ppm). On Day 2, participants in sampling boat A had high benzene exposure (0.87-1.52 ppm) compared to participants in sampling boat B (0.01-0.02 ppm), on the ships (0.06-0.10 ppm), and on the bridge (0.004-0.01 ppm). Overall, the participants in the sampling boats had the highest exposure to all of the compounds measured. The light crude oil yielded a five times higher concentration of total volatile organic compounds in air in the sampling boats (max 510 ppm) than the heavy crude oil (max 100 ppm) but rapidly declined to <20 ppm within 24 min after release of oil, indicating short periods of exposure. The personal exposure to benzene downwind and close to the oil slick during spills of light crude oil was relatively high, with concentration levels approaching the occupational exposure limits for several participants. For bulk spill scenarios like in this study, cleanup should not be initiated the first 30-60 min to allow for evaporation, while appropriate personal protective equipment should be used in continuous spills when working downwind and close to the oil slick. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Risk of Lung Cancer Mortality in Nuclear Workers from Internal Exposure to Alpha Particle-emitting Radionuclides

PubMed Central

Atkinson, Will; Bérard, Philippe; Bingham, Derek; Birchall, Alan; Blanchardon, Eric; Bull, Richard; Guseva Canu, Irina; Challeton-de Vathaire, Cécile; Cockerill, Rupert; Do, Minh T.; Engels, Hilde; Figuerola, Jordi; Foster, Adrian; Holmstock, Luc; Hurtgen, Christian; Laurier, Dominique; Puncher, Matthew; Riddell, Anthony E.; Samson, Eric; Thierry-Chef, Isabelle; Tirmarche, Margot; Vrijheid, Martine; Cardis, Elisabeth

2017-01-01

Background: Carcinogenic risks of internal exposures to alpha-emitters (except radon) are poorly understood. Since exposure to alpha particles—particularly through inhalation—occurs in a range of settings, understanding consequent risks is a public health priority. We aimed to quantify dose–response relationships between lung dose from alpha-emitters and lung cancer in nuclear workers. Methods: We conducted a case–control study, nested within Belgian, French, and UK cohorts of uranium and plutonium workers. Cases were workers who died from lung cancer; one to three controls were matched to each. Lung doses from alpha-emitters were assessed using bioassay data. We estimated excess odds ratio (OR) of lung cancer per gray (Gy) of lung dose. Results: The study comprised 553 cases and 1,333 controls. Median positive total alpha lung dose was 2.42 mGy (mean: 8.13 mGy; maximum: 316 mGy); for plutonium the median was 1.27 mGy and for uranium 2.17 mGy. Excess OR/Gy (90% confidence interval)—adjusted for external radiation, socioeconomic status, and smoking—was 11 (2.6, 24) for total alpha dose, 50 (17, 106) for plutonium, and 5.3 (−1.9, 18) for uranium. Conclusions: We found strong evidence for associations between low doses from alpha-emitters and lung cancer risk. The excess OR/Gy was greater for plutonium than uranium, though confidence intervals overlap. Risk estimates were similar to those estimated previously in plutonium workers, and in uranium miners exposed to radon and its progeny. Expressed as risk/equivalent dose in sieverts (Sv), our estimates are somewhat larger than but consistent with those for atomic bomb survivors. See video abstract at, http://links.lww.com/EDE/B232. PMID:28520643

Uranium accumulation in modern and ancient Fe-oxide sediments: Examples from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and Yubileynoe massive sulfide deposit (South Urals, Russia)

NASA Astrophysics Data System (ADS)

Ayupova, N. R.; Melekestseva, I. Yu.; Maslennikov, V. V.; Tseluyko, A. S.; Blinov, I. A.; Beltenev, V. E.

2018-05-01

Fe-oxyhydroxide sediments (gossans) from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and hematite-carbonate-quartz rocks (gossanites) from the Yubileynoe Cu-Zn VHMS deposit (South Urals) are characterized by anomalously high U contents (up to 352 ppm and 73 ppm, respectively). In gossans from the Ashadze-2 hydrothermal sulfide field, rare isometric anhedral uraninite grains (up to 2 μm) with outer P- and Ca-rich rims, and numerous smaller (<1 μm) grains, occur in Fe-oxyhydroxides and sepiolite, associated with pyrite, isocubanite, chalcopyrite, galena, atacamite and halite. In gossanites from the Yubileynoe deposit, numerous uraninite particles (<3 μm) are associated with apatite, V-rich Mg-chlorite, micro-nodules of pyrite, Se-bearing galena, hessite and acanthite in a hematite-carbonate-quartz matrix. Small (1-3 μm) round grains of uraninite, which locally coalesce to large grains up to 10 μm in size, are associated with authigenic chalcopyrite. The similar diagenetic processes of U accumulation in modern and ancient Fe-oxyhydroxide sediments were the result of U fixation from seawater during the oxidation of sulfide minerals. Uraninite in gossanites was mainly deposited from diagenetic pore fluids, which circulated in the sulfide-hyaloclast-carbonate sediments.

Exposure to BTEX and Ethers in Petrol Station Attendants and Proposal of Biological Exposure Equivalents for Urinary Benzene and MTBE.

PubMed

Campo, Laura; Rossella, Federica; Mercadante, Rosa; Fustinoni, Silvia

2016-04-01

To assess exposure to benzene (BEN) and other aromatic compounds (toluene, ethylbenzene, m+p-xylene, o-xylene) (BTEX), methyl tert-butyl ether (MTBE), and ethyl tert-butyl ether (ETBE) in petrol station workers using air sampling and biological monitoring and to propose biological equivalents to occupational limit values. Eighty-nine petrol station workers and 90 control subjects were investigated. Personal exposure to airborne BTEX and ethers was assessed during a mid-week shift; urine samples were collected at the beginning of the work week, prior to and at the end of air sampling. Petrol station workers had median airborne exposures to benzene and MTBE of 59 and 408 µg m(-3), respectively, with urinary benzene (BEN-U) and MTBE (MTBE-U) of 339 and 780 ng l(-1), respectively. Concentrations in petrol station workers were higher than in control subjects. There were significant positive correlations between airborne exposure and the corresponding biological marker, with Pearson's correlation coefficient (r) values of 0.437 and 0.865 for benzene and MTBE, respectively. There was also a strong correlation between airborne benzene and urinary MTBE (r = 0.835). Multiple linear regression analysis showed that the urinary levels of benzene were influenced by personal airborne exposure, urinary creatinine, and tobacco smoking [determination coefficient (R(2)) 0.572], while MTBE-U was influenced only by personal exposure (R(2) = 0.741). BEN-U and MTBE-U are sensitive and specific biomarkers of low occupational exposures. We propose using BEN-U as biomarker of exposure to benzene in nonsmokers and suggest 1457 ng l(-1) in end shift urine samples as biological exposure equivalent to the EU occupational limit value of 1 p.p.m.; for both smokers and nonsmokers, MTBE-U may be proposed as a surrogate biomarker of benzene exposure, with a biological exposure equivalent of 22 µg l(-1) in end shift samples. For MTBE exposure, we suggest the use of MTBE-U with a biological exposure equivalent of 22 µg l(-1) corresponding to the occupational limit value of 50 p.p.m. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Performance analysis of gamma ray spectrometric parameters on digital signal and analog signal processing based MCA systems using NaI(Tl) detector.

PubMed

Kukreti, B M; Sharma, G K

2012-05-01

Accurate and speedy estimations of ppm range uranium and thorium in the geological and rock samples are most useful towards ongoing uranium investigations and identification of favorable radioactive zones in the exploration field areas. In this study with the existing 5 in. × 4 in. NaI(Tl) detector setup, prevailing background and time constraints, an enhanced geometrical setup has been worked out to improve the minimum detection limits for primordial radioelements K(40), U(238) and Th(232). This geometrical setup has been integrated with the newly introduced, digital signal processing based MCA system for the routine spectrometric analysis of low concentration rock samples. Stability performance, during the long counting hours, for digital signal processing MCA system and its predecessor NIM bin based MCA system has been monitored, using the concept of statistical process control. Monitored results, over a time span of few months, have been quantified in terms of spectrometer's parameters such as Compton striping constants and Channel sensitivities, used for evaluating primordial radio element concentrations (K(40), U(238) and Th(232)) in geological samples. Results indicate stable dMCA performance, with a tendency of higher relative variance, about mean, particularly for Compton stripping constants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pyrolysis gas chromatography-mass spectrometry to characterize organic matter and its relationship to uranium content of Appalachian Devonian black shales

USGS Publications Warehouse

Leventhal, J.S.

1981-01-01

Gas Chromatographic analysis of volatile products formed by stepwise pyrolysis of black shales can be used to characterize the kerogen by relating it to separated, identified precursors such as land-derived vitrinite and marine-source Tasmanites. Analysis of a Tasmanites sample shows exclusively n-alkane and -alkene pyrolysis products, whereas a vitrinite sample shows a predominance of one- and two-ring substituted aromatics. For core samples from northern Tennessee and for a suite of outcrop samples from eastern Kentucky, the organic matter type and the U content (<10-120ppm) show variations that are related to precursor organic materials. The samples that show a high vitrinite component in their pyrolysis products are also those samples with high contents of U. ?? 1981.

Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

PubMed

Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

2017-02-01

The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h -1 in Lambapur-Peddagattu, 186 ± 77 nGy h -1 in Chitrial and 63 ± 22 nGy h -1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h -1 . The gamma absorbed dose rates in nGy h -1 were converted to annual effective dose rates in mSv y -1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y -1 , which is much lower than the recommended limit of 1 mSv y -1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas to assess any changes in gamma radiation levels due to mining and milling activities in future. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz

USGS Publications Warehouse

Fox, P.M.; Davis, J.A.; Zachara, J.M.

2006-01-01

Recent studies of uranium(VI) geochemistry have focused on the potentially important role of the aqueous species, CaUO2 (CO3)32- and Ca2 UO2(CO3)30(aq), on inhibition of microbial reduction and uranium(VI) aqueous speciation in contaminated groundwater. However, to our knowledge, there have been no direct studies of the effects of these species on U(VI) adsorption by mineral phases. The sorption of U(VI) on quartz and ferrihydrite was investigated in NaNO3 solutions equilibrated with either ambient air (430 ppm CO2) or 2% CO2 in the presence of 0, 1.8, or 8.9 mM Ca2+. Under conditions where the Ca2UO2(CO3)30 (aq) species predominates U(VI) aqueous speciation, the presence of Ca in solution lowered U(VI) adsorption on quartz from 77% in the absence of Ca to 42% and 10% at Ca concentrations of 1.8 and 8.9 mM, respectively. U(VI) adsorption to ferrihydrite decreased from 83% in the absence of Ca to 57% in the presence of 1.8 mM Ca. Surface complexation model predictions that included the formation constant for aqueous Ca2UO2(CO3)30(aq) accurately simulated the effect of Ca2+ on U(VI) sorption onto quartz and ferrihydrite within the thermodynamic uncertainty of the stability constant value. This study confirms that Ca2+ can have a significant impact on the aqueous speciation of U(VI), and consequently, on the sorption and mobility of U(VI) in aquifers. ?? 2005 Elsevier Inc. All rights reserved.

HPLC separation post-column reaction, UV-visible and fluorescence detection of trace UO/sub 2//sup 2 +//U/sup 4 +/ species in aqueous solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karimi, A.R.

In this study a method for the measurement of uranium in natural waters at sub-ppB concentration levels by the separation and determination of U/sup 4 +/ and UO/sub 2//sup 2 +/ species is proposed. Reversed phase high performance liquid chromatography, followed by a post-column reaction and a sensitive UV-visible detection system was the method of choice to determine qualitatively and quantitatively the two uranium species. Also a cation-exchange and fluorescence detection system was studied for separation and determination of UO/sub 2//sup 2 +/ ions. Uranyl ion was selectively complexed with L-phenylalanine moetie in the sample solution containing U/sup 4 +/more » ions. Uranium (IV)/U(VI)-ligand was separated on a C/sub 18/ column with acetate buffer. Hexanesulfonate was found to be the choice for ion-pair reagent. The separation was best done with the acetate buffer at .01 M concentration and pH of 3.5. Absorption of the two species were measured after a post-column reaction with Arsenazo-III. Chromatographic parameters were calculated and a calibration curves were constructed. The detection limit for the procedure was 0.7 ..mu..g/mo and 1.2..mu..g/ml for U(IV) and U(VI) respectively. When U(VI) was separated on the cation-exchange column the limit of detection was calculated to be 1 ..mu..g/ml. The direct fluorometric method for U(VI) measurement results in a detection limit of 2 ppB and upper concentration limit of 2 ppM. The effect of interfering ions in the direct method of determination could be eliminated by dilution of sample solution.« less

Public health, climate, and economic impacts of desulfurizing jet fuel.

PubMed

Barrett, Steven R H; Yim, Steve H L; Gilmore, Christopher K; Murray, Lee T; Kuhn, Stephen R; Tai, Amos P K; Yantosca, Robert M; Byun, Daewon W; Ngan, Fong; Li, Xiangshang; Levy, Jonathan I; Ashok, Akshay; Koo, Jamin; Wong, Hsin Min; Dessens, Olivier; Balasubramanian, Sathya; Fleming, Gregg G; Pearlson, Matthew N; Wollersheim, Christoph; Malina, Robert; Arunachalam, Saravanan; Binkowski, Francis S; Leibensperger, Eric M; Jacob, Daniel J; Hileman, James I; Waitz, Ian A

2012-04-17

In jurisdictions including the US and the EU ground transportation and marine fuels have recently been required to contain lower concentrations of sulfur, which has resulted in reduced atmospheric SO(x) emissions. In contrast, the maximum sulfur content of aviation fuel has remained unchanged at 3000 ppm (although sulfur levels average 600 ppm in practice). We assess the costs and benefits of a potential ultra-low sulfur (15 ppm) jet fuel standard ("ULSJ"). We estimate that global implementation of ULSJ will cost US$1-4bn per year and prevent 900-4000 air quality-related premature mortalities per year. Radiative forcing associated with reduction in atmospheric sulfate, nitrate, and ammonium loading is estimated at +3.4 mW/m(2) (equivalent to about 1/10th of the warming due to CO(2) emissions from aviation) and ULSJ increases life cycle CO(2) emissions by approximately 2%. The public health benefits are dominated by the reduction in cruise SO(x) emissions, so a key uncertainty is the atmospheric modeling of vertical transport of pollution from cruise altitudes to the ground. Comparisons of modeled and measured vertical profiles of CO, PAN, O(3), and (7)Be indicate that this uncertainty is low relative to uncertainties regarding the value of statistical life and the toxicity of fine particulate matter.

Subchronic mercury exposure in coturnix and a method of hazard evaluation

USGS Publications Warehouse

Hill, E.F.; Soares, J.H.

1984-01-01

The sublethal toxicity of inorganic (HgCI 2) and organic (CH3HgCI) mercury chloride was studied in coturnix (Corurnix japonica) by feeding them mercuric compounds (CH3HgCI at concentrations of 0.125,0.5,2 and 8 ppm; HgCI2 at 0.5, 2, 8 and 32 ppm) in ad libitum diets from hatching to adulthood. Differences of response to the mercurials were compared on the basis of selected indicator enzymes and plasma chemistries. Comparisons of response to equivalent concentrations of the two mercurials and dose-response relationships were made at 1,3,5,7 and 9 weeks. Changes of activity were detected for brain acetylcholinesterase (AChE) and the plasma enzymes aspartate aminotransferase (ASA T), butyrylcholinesterase (BChE), lactate dehydrogenase (LDH) and ornithine carbamoyl transferase (OCT). Changes of ASA T, LDH and OCT were then quantified by probit analysis and the mercurials were compared through their median effective concentrations (EC50). This quantal procedure was based on the establishment of normal control values for each enzyme and then classifying mercury-treated outliers (more than + 2 SD) as respondents. The EC50 values at 9 weeks for ASA T, LDH and OCT, respectively, were 9, 3 and 63 ppm for HgCl 2, and 5, 1 and 4 ppm for CH3HgCI. These results provided the basis for two hazard indices that were calculated by dividing the EC50 into the oral LD50 and the 5-d dietary LC50. Mercury also had contradictory effects on gonadal maturation in both sexes.

Occupational health concerns in the welding industry.

PubMed

Korczynski, R E

2000-12-01

The Workplace Safety and Health Branch initiated a proactive study in the welding industry in Manitoba. Eight welding companies participated in this study. Health concerns raised by welders were welders' flash, sore/red/teary eyes, headaches, nosebleeds, and a black mucous discharge from their nasal membrane. Most welders expressed concern regarding excessive smoke levels in the workplace and inadequate ventilation. Types of welding identified were MIG mild steel, MIG stainless steel, and TIG aluminum. Monitoring involved an assessment of noise levels, fume composition, and carbon monoxide and ozone concentrations. Metal analyses were according to National Institute for Occupational Safety and Health (NIOSH) Method 7300. Noise dosimeters used were the Quest model 100 and Micro 14 & 15. Carbon monoxide was monitored using the Gastech Model 4700 and ozone using the AID Portable Ozone Meter Model 560. In Manitoba, a hearing conservation program is required when the equivalent sound exposure level (normalized Lex 8-hr) exceeds 80 dBA-weighted. The American Conference of Governmental Industrial Hygienists' threshold limit value-time weighted average (ACGIH TLV-TWA) for iron is 5.0 mg/m3, manganese is 0.2 mg/m3, carbon monoxide is 25 ppm, and ozone is 0.05 ppm (heavy work), 0.08 ppm (moderate work), and 0.1 ppm (light work). Welders' personal exposures to manganese ranged from 0.01-4.93 mg/m3 (N = 42; AM = 0.5; GM = 0.2; SD +/- 0.9; GSD +/- 3.2) and to iron ranged from 0.04-16.29 mg/m3 (N = 42; AM = 3.0; GM = 1.4; SD +/- 3.5; GSD +/- 2.5). Noise exposures ranged from 79-98 dBA (N = 44; AM = 88.9; GM = 88.8; SD +/- 4.2; GSD +/- 1.0). Carbon monoxide levels were less than 5.0 ppm (at source) and ozone levels varied from 0.4-0.6 ppm (at source). Ventilation upgrades in the workplace were required in most welding shops. Only 7 percent of the welders wore respiratory protection. A hearing conservation program and hearing protection were required at all monitored workplaces.

Physicochemical and Antioxidant Properties of Honeys from the Sundarbans Mangrove Forest of Bangladesh

PubMed Central

Islam, M Rabiul; Pervin, Tahmina; Hossain, Hemayet; Saha, Badhan; Hossain, Sheikh Julfikar

2017-01-01

This study evaluated the physicochemical, nutritional, antioxidant, and phenolic properties of ten honey samples from the Sundarbans mangrove forest, Bangladesh. The average pH, electrical conductivity, total dissolved solid, ash, moisture, hydroxymethyl furfural, titrable acidity, and absorbance were 4.3, 0.38 mS/cm, 187.5 ppm, 0.14%, 17.88%, 4.4 mg/kg, 37.7 meq/kg, and 483 mAU, respectively. In the honeys, the average contents of Ca, Cu, Fe, K, Mg, Mn, and Na were 95.5, 0.19, 6.4, 302, 39.9, 3.4, and 597 ppm, respectively, whereas Cd, Cr, Pb, and Ni were not found. The average contents of total sugar, protein, lipid, vitamin C, polyphenols, flavonoids, and anthocyanins in the honeys were 69.3%, 0.8%, 0.29%, 107.3 mg/kg, 757.2 mg gallic acid equivalent/kg, 43.1 mg chatechin equivalent/kg, and 5.4 mg/kg, respectively. The honeys had strong 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, reducing power and total antioxidant capacity. High-performance liquid chromatography analysis of the honey fractions revealed the quantification of six polyphenols namely, (+)-catechin, (−)-epicatechin, p-caumeric acid, syringic acid, trans-cinnamic acid, and vanillic acid at 194.98, 330.34, 74.64, 218.97, 49.55, and 118.84 mg/kg, respectively. Therefore, the honeys in the Sundarbans are of excellent quality and a prospective source of polyphenols, and antioxidants. PMID:29333387

Physicochemical and Antioxidant Properties of Honeys from the Sundarbans Mangrove Forest of Bangladesh.

PubMed

Islam, M Rabiul; Pervin, Tahmina; Hossain, Hemayet; Saha, Badhan; Hossain, Sheikh Julfikar

2017-12-01

This study evaluated the physicochemical, nutritional, antioxidant, and phenolic properties of ten honey samples from the Sundarbans mangrove forest, Bangladesh. The average pH, electrical conductivity, total dissolved solid, ash, moisture, hydroxymethyl furfural, titrable acidity, and absorbance were 4.3, 0.38 mS/cm, 187.5 ppm, 0.14%, 17.88%, 4.4 mg/kg, 37.7 meq/kg, and 483 mAU, respectively. In the honeys, the average contents of Ca, Cu, Fe, K, Mg, Mn, and Na were 95.5, 0.19, 6.4, 302, 39.9, 3.4, and 597 ppm, respectively, whereas Cd, Cr, Pb, and Ni were not found. The average contents of total sugar, protein, lipid, vitamin C, polyphenols, flavonoids, and anthocyanins in the honeys were 69.3%, 0.8%, 0.29%, 107.3 mg/kg, 757.2 mg gallic acid equivalent/kg, 43.1 mg chatechin equivalent/kg, and 5.4 mg/kg, respectively. The honeys had strong 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, reducing power and total antioxidant capacity. High-performance liquid chromatography analysis of the honey fractions revealed the quantification of six polyphenols namely, (+)-catechin, (-)-epicatechin, p -caumeric acid, syringic acid, trans -cinnamic acid, and vanillic acid at 194.98, 330.34, 74.64, 218.97, 49.55, and 118.84 mg/kg, respectively. Therefore, the honeys in the Sundarbans are of excellent quality and a prospective source of polyphenols, and antioxidants.

New Constraints on the Geochemistry of the Millennium Eruption of Mount Paektu (Changbaishan), Democratic People's Republic of Korea/China

NASA Astrophysics Data System (ADS)

Iacovino, K.; Kim, J. S.; Sisson, T. W.; Lowenstern, J. B.; Jang, J. N.; Song, K. H.; Ham, H. H.; Ri, K. H.; Donovan, A. R.; Oppenheimer, C.; Hammond, J. O. S.; Weber Liu, K.; Ryu, K. R.

2015-12-01

Mount Paektu (also known as Changbaishan) is a large caldera located on the border between China and the Democratic People's Republic of Korea. Circa 946 AD, Paektu produced one of the largest volcanic eruptions in recorded history, the so-called Millennium Eruption (ME), whose combined fall and pyroclastic flow deposits total approximately 25 km3 dense rock equivalent (95% commendite, 5% late stage trachyte). Despite its recent and potentially destructive history, the volcano is not well studied due to its relative inaccessibility. A seismic swarm beneath the volcano's summit in 2002-2005 spurred a unique collaboration between scientists from the DPRK, US, and the UK with the goals of characterizing Paektu's eruptive history and assessing its current state of activity. We present new results from this collaboration, including major and trace element (XRF, EMP and SHRIMP-RG) and volatile data (SHRIMP-RG and FTIR) on feldspar-, clinopyroxene-, and olivine-hosted melt inclusions (MI), matrix glasses, and bulk pumices from four ME comendites and one ME trachyte. MI are halogen rich (F≤4000 ppm, Cl≤5000 ppm) with moderate S (≤250 ppm) and H2O (≤4 wt%) and minimal CO2 (≤15 ppm, detection limit ~2 ppm). H2O contents in comendite MI indicate saturation pressures (at 725 °C) of ~150 MPa, corresponding to a magma chamber depth of ~6 km, similar to the depth inferred for the magmatic injection thought to have resulted in the 2002-05 earthquake swarm. ME comendite is consistent with a ca. 25% residual melt by fractional crystallization from an ME trachyte parent. Published U-series zircon ages from ME comendite indicate a magma residence time of 11ky. Thus, the late stage ME trachyte likely represents a mafic recharge event of a melt separate from but geochemically similar to the original ME comendite parent.

Replacing Burning of Fossil Fuels with Solar Cell and Wind Energy: How Important and How Soon?

NASA Astrophysics Data System (ADS)

Partain, L., II; Hansen, R. T.; Hansen, S. F.; Bennett, D.; Newlands, A.

2016-12-01

The IPCC indicated that atmospheric CO2 rise should stop to control global climate change. CO2 is the longest lived, most problematic anthropogenic greenhouse emission from burning fossil fuel. For 2000 years atmospheric CO2 concentration remained 280 ppm until 1870, when it rose sharply and nonlinearly to 400 ppm, correlated with a 1oC global mean temperature rise. Antarctic ice core data for the past 400,000 years indicate, 80 ppm shifts in atmospheric CO2 concentrations with 10,000-30,000 year interglacial periods at 280 ppm, were between ice-age glacial periods of 75,000-100,000 years at 200 ppm. The last 12,000-year interglacial "Goldilocks" period so far spans 4 civilizations: 6000 years of Western, 4000-5000 years of Inca and Aztec and 7000-8000 years of Chinese civilizations. The UN-led 2015 Paris Agreement set a goal limiting temperature rise to 2oC to prevent devastating climate change. Unfortunately IPCC modeling found a substantial probability of a rise by 4oC or more should all current fossil fuels be burned by 2100. This would result in weather extremes, rising oceans, storm surges and temperatures where low-lying coastal regions, Pacific Islands and large equatorial regions of the world could become uninhabitable. By Swanson's Law, an empirical learning curve observation, solar cell production costs drop 50% for every 10X increase in their cumulative production. After 40 years and over 5 orders-of-magnitude cumulative production increase, solar cells currently provide over 1% of the world's electricity generating capacity at a cost competitive with electricity generated from burning fossil fuels. If their cumulative generating capacity keeps doubling every 2 years (similar to Moore's Law), energy equivalent to all the world's electricity generating capacity could be provided by solar cells by 2028. The variability of solar cell energy can be mitigated by combining it with wind power, storage, super grids, space mirrors, and demand response.

Chemical composition, iron bioavailability, and antioxidant activity of Kappaphycus alvarezzi (Doty).

PubMed

Fayaz, Mohamed; Namitha, K K; Murthy, K N Chidambara; Swamy, M Mahadeva; Sarada, R; Khanam, Salma; Subbarao, P V; Ravishankar, G A

2005-02-09

Kappaphycus alvarezzi, an edible seaweed from the west coast of India, was analyzed for its chemical composition. It was found that K. alvarezzi is rich in protein (16.24% w/w) and contains a high amount of fiber (29.40% w/w) and carbohydrates (27.4% w/w). K. alvarezzi showed vitamin A activity of 865 mug retinal equivalents/100 g of sample. It contained a higher quantity of unsaturated fatty acids (44.50% of the total), in which relative percentage of oleic acid was 11%, cis-heptadecanoic acid 13.50%, and linoleic acid 2.3% and 37.0% of saturated fatty acids (mainly heptadecanoic acid). K. alvarezziwas also found to be good source of minerals, viz 0.16% of calcium, 0.033% of iron, and 0.016% of zinc, which are essential for various vital biological activities. Bioavailability of iron by in vitro methods showed a higher efficiency in intestinal conditions than in stomach conditions. Ascorbic acid influenced higher bioavailability of iron. Successive extracts of n-hexane, acetone, ethyl acetate, ethanol, and direct extractables of chloroform/methanol (1:1 and 2:1) were screened for antioxidant activity using a beta-carotene linoleic acid model system (B-CLAMS), DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) model system and hydroxyl radical scavenging activity. The chloroform/methanol (2:1) extract has shown 82.5% scavenging activity at 1000 ppm. Acetone fraction extracts at the 1000 ppm level showed 63.31% antioxidant activity in beta-carotene linoleic acid system. The acetone extract showed 46.04% scavenging activity at 1000 ppm concentration. In the case of hydroxyl radical scavenging activity, all the extracts showed better activity at the concentrations of 25 and 50 ppm, where at the 50 ppm level ethyl acetate extract showed 76.0%, acetone 75.12%, and hexane 71.15% activity, respectively. Results of this study suggest the utility of K. alvarezzi (Eucheuma) for various nutritional products, including antioxidant for use as health food or nutraceutical supplement.

Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico.

USGS Publications Warehouse

Wenrich, K.J.; Modreski, P.J.; Zielinski, R.A.; Seeley, J.L.

1982-01-01

Margaritasite, (Cs,K,H3O)2(UO2)2V2O8.nH2O (where Cs > K, H3O and n approx 1), a 10.514, b 8.425, c 7.25 A, beta 106.01o, P21/a, Z = 2, is a newly recognized uranium ore mineral named for the Margaritas deposit, Pena Blanca uranium district, Chihuahua, Mexico, at which it was discovered. A Cs-rich analogue of carnotite, margaritasite is the natural equivalent of synthetic Cs-uranyl vanadate (A.M. 43- 799, 50-825). A fine-grained yellow mineral, it is most easily distinguished from carnotite by XRD; X-ray powder patterns (CuKalpha radiation) show that the (001) reflection of margaritasite lies at 12.7o (2theta ), while that of carnotite is found at 13.8o (2theta ). The shift of the (001) reflection in margaritasite reflects the structural changes caused when Cs occupies the sites filled by K in carnotite. Synthesis experiments indicate that margaritasite also differs from carnotite in a higher-T hydrothermal origin. Chemical analyses and XRD data for margaritasite and synthetic Cs- carnotite, and chemical analyses for rocks from Sierra Pena Blanca and vicinity, are tabulated.-J.A.Z.

Adjustment of geochemical background by robust multivariate statistics

USGS Publications Warehouse

Zhou, D.

1985-01-01

Conventional analyses of exploration geochemical data assume that the background is a constant or slowly changing value, equivalent to a plane or a smoothly curved surface. However, it is better to regard the geochemical background as a rugged surface, varying with changes in geology and environment. This rugged surface can be estimated from observed geological, geochemical and environmental properties by using multivariate statistics. A method of background adjustment was developed and applied to groundwater and stream sediment reconnaissance data collected from the Hot Springs Quadrangle, South Dakota, as part of the National Uranium Resource Evaluation (NURE) program. Source-rock lithology appears to be a dominant factor controlling the chemical composition of groundwater or stream sediments. The most efficacious adjustment procedure is to regress uranium concentration on selected geochemical and environmental variables for each lithologic unit, and then to delineate anomalies by a common threshold set as a multiple of the standard deviation of the combined residuals. Robust versions of regression and RQ-mode principal components analysis techniques were used rather than ordinary techniques to guard against distortion caused by outliers Anomalies delineated by this background adjustment procedure correspond with uranium prospects much better than do anomalies delineated by conventional procedures. The procedure should be applicable to geochemical exploration at different scales for other metals. ?? 1985.

A stream sediment geochemical survey of the Ganga River headwaters in the Garhwal Himalaya

USGS Publications Warehouse

Mukherjee, P.K.; Purohit, K.K.; Saini, N.K.; Khanna, P.P.; Rathi, M.S.; Grosz, A.E.

2007-01-01

This study models geochemical and adjunct geologic data to define provinces that are favorable for radioactive-mineral exploration. A multi-element bed-sediment geochemical survey of streams was carried out in the headwaters region of the Ganga River in northern India. Overall median values for uranium and thorium (3.6 and 13.8 ppm; maxima of 4.8 and 19.0 ppm and minima of 3.1 and 12.3 ppm respectively) exceed average upper crustal abundances (2.8 and 10.7 ppm) for these radioactive elements. Anomalously high values reach up to 8.3 and 30.1 ppm in thrust zone rocks, and 11.4 and 22.5 ppm in porphyroids. At their maxima, these abundances are nearly four- and three-fold (respectively) enriched in comparison to average crustal abundances for these rock types. Deformed, metamorphosed and sheared rocks are characteristic of the main central thrust zone (MCTZ). These intensively mylonitized rocks override and juxtapose porphyritic (PH) and proterozoic metasedimentary rock sequences (PMS) to the south. Granitoid rocks, the major protoliths for mylonites, as well as metamorphosed rocks in the MCT zone are naturally enriched in radioelements; high values associated with sheared and mylonitized zones are coincident with reports of radioelement mineralization and with anomalous radon concentrations in soils. The radioelement abundance as well as REE abundance shows a northward enrichment trend consistent with increasing grade of metamorphism indicating deformation-induced remobilization of these elements. U and Th illustrate good correlation with REEs but not with Zr. This implies that zircon is not a principal carrier of U and Th within the granitoid-dominant thrust zone and that other radioelement-rich secondary minerals are present in considerable amounts. Thus, the relatively flat, less fractionated, HREE trend is also not entirely controlled by zircon. The spatial correlation of geologic boundary zones (faults, sheared zones) with geochemical and with geophysical (Rn) anomalies infers ore mineralization by hydrothermal processes generated during multiple episodes of deformation and thrusting. The geologic setting of the anomalies also suggests that crystalline rocks (MCT Zone) along the nearly 2500 km length of the LesserHimalayan belt, where in the vicinity of thrust and fault zones, have potential for radioelement mineralization. Zones of higher concentrations of radioelements delineated by this study and locations of anomalous radon discharge determined by other investigations may indicate a potential health hazard over the long term. However, the low human population density precludes direct manifestation of health effects attributable to chronic exposure to these radioelements; however, the magnitude of natural concentrations suggests the need for more detailed studies and monitoring. Copyright ?? 2007 by The Geochemical Society of Japan.

Performance of a High-Concentration Erbium-Doped Fiber Amplifier with 100 nm Amplification Bandwidth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hajireza, P.; Shahabuddin, N. S.; Abbasi-Zargaleh, S.

2010-07-07

Increasing demand for higher bandwidth has driven the need for higher Wavelength Division Multiplexing (WDM) channels. One of the requirements to achieve this is a broadband amplifier. This paper reports the performance of a broadband, compact, high-concentration and silica-based erbium-doped fiber amplifier. The amplifier optimized to a 2.15 m long erbium-doped fiber with erbium ion concentration of 2000 ppm. The gain spectrum of the amplifier has a measured amplification bandwidth of 100 nm using a 980 nm laser diode with power of 150 mW. This silica-based EDFA shows lower noise figure, higher gain and wider bandwidth in shorter wavelengths comparedmore » to Bismuth-based EDFA with higher erbium ion concentration of 3250 ppm at equivalent EDF length. The silica-based EDF shows peak gain at 22 dB and amplification bandwidth between 1520 nm and 1620 nm. The lowest noise figure is 5 dB. The gain is further improved with the implementation of enhanced EDFA configurations.« less

Characterization Of Nuclear Materials Using Time-Of-Flight ICP-MS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buerger, Stefan; Riciputi, Lee R; Bostick, Debra A

2006-01-01

The investigation of illicit trafficking of nuclear materials, nuclear safeguards analysis, and non-proliferation control requires sensitive and isotope-selective detection methods to gain crucial nuclear forensic information like isotope 'fingerprints' and multi-element signatures. The advantage of time-of-flight (TOF) mass spectrometry - quasi-simultaneous multi-mass analysis - combined with an inductively coupled plasma (ICP) ion source provides an analytical instrument with multi-element and multi-isotope capability and good detection limits. A TOF-ICP-MS system thus appears to be an advantageous choice for the investigation and characterization of nuclear materials. We present here results using a GBC OptiMass 8000 time-of-flight ICP-MS for the isotope screening ofmore » solid samples by laser ablation and the multi-element determination of impurities in uranium ore concentrates using matrix matched standards. A laser ablation system (New Wave Research, UP 213) coupled to the TOF-ICP-MS instrument has been used to optimize the system for analysis of non-radioactive metal samples of natural isotopic composition for a variety of elements including Cu, Sr, Zr, Mo, Cd, In, Ba, Ta, W, Re, Pt, and Pb in pure metals, alloys, and glasses to explore precision, accuracy, and detection limits. Similar methods were then applied to measure uranium. When the laser system is optimized, no mass bias correction is required. Precision and accuracy for the determination of the isotopic composition is typically 1 - 3% for elemental concentrations of as little as 50 ppm in the matrix, with no requirement for sample preparation. The laser ablation precision and accuracy are within ~10x of the instrumental limits for liquid analysis (0.1%). We have investigated the capabilities of the TOF-ICP-MS for the analysis of impurities in uranium matrices. Matrix matching has been used to develop calibration curves for a range of impurities (alkaline, earth-alkaline, transition metals, and rare earth elements). These calibration curves have been used to measure impurities in a number of uranium samples. The results from the TOF-ICP-MS will be compared with other mass spectrometric methods.« less

Universal Decoder for PPM of any Order

NASA Technical Reports Server (NTRS)

Moision, Bruce E.

2010-01-01

A recently developed algorithm for demodulation and decoding of a pulse-position- modulation (PPM) signal is suitable as a basis for designing a single hardware decoding apparatus to be capable of handling any PPM order. Hence, this algorithm offers advantages of greater flexibility and lower cost, in comparison with prior such algorithms, which necessitate the use of a distinct hardware implementation for each PPM order. In addition, in comparison with the prior algorithms, the present algorithm entails less complexity in decoding at large orders. An unavoidably lengthy presentation of background information, including definitions of terms, is prerequisite to a meaningful summary of this development. As an aid to understanding, the figure illustrates the relevant processes of coding, modulation, propagation, demodulation, and decoding. An M-ary PPM signal has M time slots per symbol period. A pulse (signifying 1) is transmitted during one of the time slots; no pulse (signifying 0) is transmitted during the other time slots. The information intended to be conveyed from the transmitting end to the receiving end of a radio or optical communication channel is a K-bit vector u. This vector is encoded by an (N,K) binary error-correcting code, producing an N-bit vector a. In turn, the vector a is subdivided into blocks of m = log2(M) bits and each such block is mapped to an M-ary PPM symbol. The resultant coding/modulation scheme can be regarded as equivalent to a nonlinear binary code. The binary vector of PPM symbols, x is transmitted over a Poisson channel, such that there is obtained, at the receiver, a Poisson-distributed photon count characterized by a mean background count nb during no-pulse time slots and a mean signal-plus-background count of ns+nb during a pulse time slot. In the receiver, demodulation of the signal is effected in an iterative soft decoding process that involves consideration of relationships among photon counts and conditional likelihoods of m-bit vectors of coded bits. Inasmuch as the likelihoods of all the m-bit vectors of coded bits mapping to the same PPM symbol are correlated, the best performance is obtained when the joint mbit conditional likelihoods are utilized. Unfortunately, the complexity of decoding, measured in the number of operations per bit, grows exponentially with m, and can thus become prohibitively expensive for large PPM orders. For a system required to handle multiple PPM orders, the cost is even higher because it is necessary to have separate decoding hardware for each order. This concludes the prerequisite background information. In the present algorithm, the decoding process as described above is modified by, among other things, introduction of an lbit marginalizer sub-algorithm. The term "l-bit marginalizer" signifies that instead of m-bit conditional likelihoods, the decoder computes l-bit conditional likelihoods, where l is fixed. Fixing l, regardless of the value of m, makes it possible to use a single hardware implementation for any PPM order. One could minimize the decoding complexity and obtain an especially simple design by fixing l at 1, but this would entail some loss of performance. An intermediate solution is to fix l at some value, greater than 1, that may be less than or greater than m. This solution makes it possible to obtain the desired flexibility to handle any PPM order while compromising between complexity and loss of performance.

Contamination of the human food chain by uranium mill tailings piles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holtzman, R.B.; Urnezis, P.W.; Padova, A.

A study is in progress to estimate the contamination of the human food chain by uranium, /sup 230/Th, /sup 226/Ra /sup 210/Pb, and /sup 210/Po originating from tailing piles associated with uranium ore processing mills. Rabbits, cattle, vegetables, and grass were collected on or near two uranium mill sites. For controls, similar samples were obtained from areas 20 km or more from the mining and mill operations. For the onsite rabbits the mean /sup 226/Ra concentrations in muscle, lung, and kidney of 5.5, 14, and 15 pCi/kg wet, respectively, were substantially higher than those in the respective tissues of controlmore » animals (0.4, 1.5, and 0.2 pCi/kg). The levels in liver did not differ significantly between the groups. The concentrations in bone (femur and vertebra) were about 9000 and 350 pCi/kg ash for the onsite and offsite animals, respectively. The levels of /sup 210/Pb and /sup 210/Po did not differ significantly for a given tissue between the two groups, except that the /sup 210/Pb level in the kidney was greater in the onsite group. For cattle, the concentrations in muscle, liver, and kidney do not differ greatly between those grazed near the pile and the controls. The levels of /sup 226/Ra, and possibly of /sup 210/Pb, appear to be greater in the femur of the animals near the piles. Vegetables from a residential area on a mill site contained substantially greater concentrations of /sup 226/Ra and /sup 210/Pb than those reported for standard New York City diets. Grass and cattle dung from land irrigated by water containing 60 pCi/L /sup 226/Ra from uranium mines had concentrations of /sup 226/Ra and /sup 210/Pb 50 and 8 times, respectively, those in control samples. It is estimated that doubling the normal concentrations in meat and vegetables of uranium and daughter products could increase the dose equivalent rates to the skeletons of persons consuming these foods by 30 or more mrem/yr.« less

Age of the moon: An isotopic study of uranium-thorium-lead systematics of lunar samples

USGS Publications Warehouse

Tatsumoto, M.; Rosholt, J.N.

1970-01-01

Concentrations of U, Th, and Pb in Apollo 11 samples studied are low (U. 0.16 to 0.87; Th, 0.53 to 3.4; Pb, 0.29 to 1.7, in ppm) but the extremely radiogenic lead in samples allows radiometric dating. The fine dust and the breccia have a concordant age of 4.66 billion years on the basis of 207Pb/206Pb, 206Pb/238U, 207Pb/235U, and 208Pb/232Th ratios. This age is comparable with the age of meteorites and with the age generally accepted for the earth. Six crystalline and vesicular samples are distinctly younger than the dust and breccia. The 238U/235U ratio is the same as that in earth rocks, and 234U is in radioactive equilibrium with parent 238U.

Chemical characterization of gas- and oil-bearing shales by instrumental neutron activation analysis

USGS Publications Warehouse

Frost, J.K.; Koszykowski, R.F.; Klemm, R.C.

1982-01-01

The concentration of As, Ba, Ca, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, K, La, Lu, Mn, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, and Zn were determined by instrumental neutron activation analysis in block shale samples of the New Albany Group (Devonian-Mississippian) in the in the Illinois Basin. Uranium content of the samples was as high as 75 ppm and interfered in the determination of samarium, molybdenum, barium and cerium. In the determination of selenium a correction was made for interference from tantalum. U, As, Co, Mo, Ni and Sb as well as Cu, V and pyritic sulphur which were determined by other methods, were found to correlate positively with the organic carbon content of the samples. ?? 1982 Akade??miai Kiado??.

Marine anoxia and delayed Earth system recovery after the end-Permian extinction

PubMed Central

Lau, Kimberly V.; Maher, Kate; Altiner, Demir; Kelley, Brian M.; Kump, Lee R.; Lehrmann, Daniel J.; Silva-Tamayo, Juan Carlos; Weaver, Karrie L.; Yu, Meiyi; Payne, Jonathan L.

2016-01-01

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and 238U/235U isotopic compositions (δ238U) of Upper Permian−Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ238U across the end-Permian extinction horizon, from ∼3 ppm and −0.15‰ to ∼0.3 ppm and −0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans—characterized by prolonged shallow anoxia that may have impinged onto continental shelves—global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe. PMID:26884155

Marine anoxia and delayed Earth system recovery after the end-Permian extinction.

PubMed

Lau, Kimberly V; Maher, Kate; Altiner, Demir; Kelley, Brian M; Kump, Lee R; Lehrmann, Daniel J; Silva-Tamayo, Juan Carlos; Weaver, Karrie L; Yu, Meiyi; Payne, Jonathan L

2016-03-01

Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and (238)U/(235)U isotopic compositions (δ(238)U) of Upper Permian-Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ(238)U across the end-Permian extinction horizon, from ∼3 ppm and -0.15‰ to ∼0.3 ppm and -0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans-characterized by prolonged shallow anoxia that may have impinged onto continental shelves-global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe.

Developmental toxicity of lead contaminated sediment to mallard ducks

USGS Publications Warehouse

Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

2000-01-01

Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

Developmental toxicity of lead-contaminated sediment to mallard ducklings

USGS Publications Warehouse

Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

2000-01-01

Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

Protein Oxidation and Sensory Quality of Brine-Injected Pork Loins Added Ascorbate or Extracts of Green Tea or Maté during Chill-Storage in High-Oxygen Modified Atmosphere.

PubMed

Jongberg, Sisse; Tørngren, Mari Ann; Skibsted, Leif H

2018-01-15

Background: Ascorbate is often applied to enhance stability and robustness of brine-injected pork chops sold for retail, but may affect protein oxidation, while plant extracts are potential substitutes. Methods: Brine-injected pork chops (weight-gain ~12%, NaCl ~0.9%) prepared with ascorbate (225 ppm), green tea extract (25 ppm gallic acid equivalents (GAE)), or maté extract (25 ppm GAE) stored (5 °C, seven days) in high-oxygen atmosphere packaging (MAP: 80% O₂ and 20% CO₂) were analyzed for color changes, sensory quality, and protein oxidation compared to a control without antioxidant. Results: No significant differences were observed for green tea and maté extracts as compared to ascorbate when evaluated based on lipid oxidation derived off-flavors, except for stale flavor, which maté significantly reduced. All treatments increased the level of the protein oxidation product, α-aminoadipic semialdehyde as compared to the control, and ascorbate was further found to increase thiol loss and protein cross-linking, with a concomitant decrease in the sensory perceived tenderness. Conclusions: Green tea and maté were found to equally protect against lipid oxidation derived off-flavors, and maté showed less prooxidative activity towards proteins as compared to ascorbate, resulting in more tender meat. Maté is a valuable substitute for ascorbate in brine-injected pork chops.

Rubemamine and Rubescenamine, Two Naturally Occurring N-Cinnamoyl Phenethylamines with Umami-Taste-Modulating Properties.

PubMed

Backes, Michael; Obst, Katja; Bojahr, Juliane; Thorhauer, Anika; Roudnitzky, Natacha; Paetz, Susanne; Reichelt, Katharina V; Krammer, Gerhard E; Meyerhof, Wolfgang; Ley, Jakob P

2015-10-07

Sensory screening of a series of naturally occurring N-cinnamoyl derivatives of substituted phenethylamines revealed that rubemamine (9, from Chenopodium album) and rubescenamine (10, from Zanthoxylum rubsecens) elicit strong intrinsic umami taste in water at 50 and 10 ppm, respectively. Sensory tests in glutamate- and nucleotide-containing bases showed that the compounds influence the whole flavor profile of savory formulations. Both rubemamine (9) and rubescenamine (10) at 10-100 ppm dose-dependently positively modulated the umami taste of MSG (0.17-0.22%) up to threefold. Among the investigated amides, only rubemamine (9) and rubescenamine (10) are able to directly activate the TAS1R1-TAS1R3 umami taste receptor. Moreover, both compounds also synergistically modulated the activation of TAS1R1-TAS1R3 by MSG. Most remarkably, rubemamine (9) was able to further positively modulate the IMP-enhanced TAS1R1-TAS1R3 response to MSG ∼ 1.8-fold. Finally, armatamide (11), zanthosinamide (13), and dioxamine (14), which lack intrinsic umami taste in vivo and direct receptor response in vitro, also positively modulated receptor activation by MSG about twofold and the IMP-enhanced MSG-induced TAS1R1-TAS1R3 responses approximately by 50%. In sensory experiments, dioxamine (14) at 25 ppm in combination with 0.17% MSG exhibited a sensory equivalent to 0.37% MSG.

A compact DD neutron generator-based NAA system to quantify manganese (Mn) in bone in vivo.

PubMed

Liu, Yingzi; Byrne, Patrick; Wang, Haoyu; Koltick, David; Zheng, Wei; Nie, Linda H

2014-09-01

A deuterium-deuterium (DD) neutron generator-based neutron activation analysis (NAA) system has been developed to quantify metals, including manganese (Mn), in bone in vivo. A DD neutron generator with a flux of up to 3*10(9) neutrons s(-1) was set up in our lab for this purpose. Optimized settings, including moderator, reflector, and shielding material and thickness, were selected based on Monte Carlo (MC) simulations conducted in our previous work. Hand phantoms doped with different Mn concentrations were irradiated using the optimized DD neutron generator irradiation system. The Mn characteristic γ-rays were collected by an HPGe detector system with 100% relative efficiency. The calibration line of the Mn/calcium (Ca) count ratio versus bone Mn concentration was obtained (R(2) = 0.99) using the hand phantoms. The detection limit (DL) was calculated to be about 1.05 μg g(-1) dry bone (ppm) with an equivalent dose of 85.4 mSv to the hand. The DL can be reduced to 0.74 ppm by using two 100% HPGe detectors. The whole body effective dose delivered to the irradiated subject was calculated to be about 17 μSv. Given the average normal bone Mn concentration of 1 ppm in the general population, this system is promising for in vivo bone Mn quantification in humans.

Products and mechanisms of the reaction of gas phase ozone with organic colorants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grosjean, D.; Druzik, J.R.; Sensharma, D.K.

1988-09-01

Studies carried out in this laboratory have shown that many artists organic colorants fade substantially when exposed to ozone in the dark. These studies typically involved pigment exposure for 12 weeks to purified air containing 0.3-0.4 ppm of ozone at ambient temperature and humidity. These laboratory conditions are equivalent to about six years of exposure inside a typical air-conditioned building in Los Angeles, and the observed fading is therefore directly relevant to possible damage to works of arts in museum settings. Organic colorants that were most ozone-fugitive included natural colorants, such as curcumin and indigo, as well as modern syntheticmore » colorants such as alizarin lakes and triphenylmethane dyes. Thus, these colorants were selected for further study with emphasis on the nature of the reaction products. Exposures were carried out on different substrates including watercolor paper, cellulose, silica gel, and Teflon. The experiments involved long-term exposure to low levels of ozone (e.g. {approximately} 0.3 ppm for 90 days) or shorter-term exposure to higher ozone concentrations (e.g. 10 ppm for 24 hours). Exposed and control samples, along with solvent and substrate blanks, were analyzed by mass spectrometry using a Kratos Scientific Instruments MS25 hexapole mass spectrometer operated in either methane chemical ionization (CI) or electron impact (EI) modes.« less

Evaluation of uranium removal by Hydrilla verticillata (L.f.) Royle from low level nuclear waste under laboratory conditions.

PubMed

Srivastava, Sudhakar; Bhainsa, K C

2016-02-01

The present study evaluated uranium (U) removal ability and tolerance to low level nuclear waste (LLNW) of an aquatic weed Hydrilla verticillata. Plants were screened for growth in 10%-50% waste treatments up to 3 d. Treatments of 20% and 50% waste imposed increasing toxicity with duration assessed in terms of change in fresh weight and in the levels of photosynthetic pigments and thiobarbituric acid-reactive substances. U concentration, however, did not show a progressive increase and was about 42 μg g(-1) dw from 20% to 50% waste at 3 d. This suggested that a saturation stage was reached with respect to U removal due to increasing toxicity. However, in another experiment with 10% waste and 10% waste+10 ppm U treatments, plants showed an increase in U concentration with the maximum level approaching 426 μg g(-1) dw at 3 d without showing any toxicity as compared to that at 20% and 50% waste treatments. Hence, plants possessed significant potential to take up U and toxicity of LLNW limited their U removal ability. This implies that the use of Hydrilla plants for U removal from LLNW is feasible at low concentrations and would require repeated harvesting at short intervals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mineral resource potential map of the Chama River Canyon Wilderness and contiguous roadless area, Rio Arriba County, New Mexico

USGS Publications Warehouse

Ridgley, Jennie L.; Light, Thomas D.

1983-01-01

The Chama River Canyon Wilderness and Roadless Area have a moderate to high potential for the presence of small deposits of copper with associated uranium and silver. These deposits, as yet undetected, would occur in the Permian Cutler Formation and in the lower part of the Triassic Chinle Formation, rock units that are, for the most part, present only in the subsurface. The presence of these deposits is inferred because such deposits occur in rocks of equivalent age in adjacent areas. Gypsum, of probable minable quality and quantity, occurs throughout the area. Oil and gas are possibly present in Pennsylvanian strata in the subsurface, although no drilling in the study area has tested this hypothesis. Other commodities, including noncopper-related uranium, kaolinite, chromium, vanadium, manganese, and bitumen, although present locally in anomalous concentrations, do not appear to constitute potential resources for these commodities.

Experimental and analytical study of nitric oxide formation during combustion of propane in a jet-stirred combustor

NASA Technical Reports Server (NTRS)

Wakelyn, N. T.; Jachimowski, C. J.; Wilson, C. H.

1978-01-01

A jet-stirred combustor, constructed of castable zirconia and with an Inconel injector, was used to study nitric oxide formation in propane-air combustion with residence times in the range from 3.2 to 3.3 msec and equivalence ratios varying from 0.7 to 1.4. Measurements were made of combustor operating temperature and of nitric oxide concentration. Maximum nitric oxide concentrations of the order of 55 ppm were found in the range of equivalence ratio from 1.0 to 1.1. A finite-rate chemical kinetic mechanism for propane combustion and nitric oxide formation was assembled by coupling an existing propane oxidation mechanism with the Zeldovich reactions and reactions of molecular nitrogen with hydrocarbon fragments. Analytical studies using this mechanism in a computer simulation of the experimental conditions revealed that the hydrocarbon-fragment-nitrogen reactions play a significant role in nitric oxide formation during fuel-rich combustion.

Effect of pomegranate (Punica granatum L.) juice on kidney, liver, heart and testis histopathological changes, and the tissues lipid peroxidation and antioxidant status in lead acetate-treated rats.

PubMed

Aksu, D S; Sağlam, Y S; Yildirim, S; Aksu, T

2017-10-31

Pomegranate juice (PJ) contains relevant amounts of active biological compounds which alleviate the detrimental effects of chronic heavy metal exposure. This study investigated the protective potential of PJ against lead-induced oxidative stress. A total of forty adult male Sprague Dawley rats were divided into four experimental groups. The animals were fed a standard pellet diet and tap water ad libitum. The rats were divided into four groups (n=10 for each group): control, lead asetat (2000 ppm), low-treated PJ- a daily dose of 2.000 ppm lead plus 30µl pomegranate juice (included 1.050 µmol total polyphenols, gallic acid equivalent), and high-treated PJ- a daily dose of 2.000 ppm lead plus 60µl pomegranate juice (included 2.100 µmol total polyphenols, gallic acid equivalent). The treatments were delivered for 5 weeks. After the treatment period, the tissues samples (kidney, liver, heart and testis) were collected. Tissue lead (Pb) and mineral amounts (copper, zinc, and iron), tissues lipid peroxidation level and antioxidant status, and tissues histopathological changes were determined. The results showed that the highest rate lead loading was in the kidney and the testis. Pomegranate juice was decreased the lead levels of soft tissues examined; increased Zn amounts in tissues of which the lead accumulation was higher (kidney and the testis); decreased the copper, zinc and the iron levels of the liver and heart tissues, without creating a weakness in antioxidant capacity of these tissues, restricted the oxidative stress by decreasing lipid peroxidation, improved both of the activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalaz (CAT), and the level of glutathione (GSH) in all the tissues examined in lead-treated groups. As histopathological findings, the cellular damage induced by lead in the tissues of the kidney, liver and the heart were observed to have been partially prevented by PJ treatment. The protective effect of PJ was more pronounced in the testis compared to those others.

Quality of Delaware River water at Trenton, New Jersey

USGS Publications Warehouse

McCarthy, Leo T.; Keighton, Walter B.

1964-01-01

Water in the Delaware River at Trenton, NJ, is a mixture of several types--water from the mountainous headwater region, water from the coal-mining regions, and water from the limestone valleys. The quantities of these types of water, in relation to the total quantity of water at Trenton, vary with changes in season and reservoir releases. The chemical quality of the water during the 17-year period 1945-61 was excellent, and the water was suitable for most uses after little or no treatment. The average concentration of dissolved solids was 86 ppm (parts per million), and 90 percent of the time it ranged from 57 to 126 ppm. Usually the pH of the water was close to 7.0 (considered to be a neutral point-neither acid nor alkaline). The hardness was less than 86 ppm 95 percent of the time. The general composition of the dissolved-solids content, in terms of equivalents, is 28 percent calcium, 14 percent magnesium, 8 percent sodium plus potassium, 43 percent bicarbonate plus sulfate, 5 percent chloride, and 2 percent nitrate. Concentrations of minerals in the river water are lowest during March, April and May (median concentration of dissolved solids 66 PPM) and are highest during August and September (median, 107 PPM). Each year an average of 880,000 tons of dissolved solids and 932,000 tons of suspended solids are carried past Trenton by the Delaware River. The greatest monthly loads of dissolved solids are in March and April, and the smallest are from July to October. Suspended-solids loads are greater when the streamflow is high but small the rest of the time. Concentration of suspended solids exceeds 100 PPM only 5 percent of the time. The headwaters in the Delaware River basin are the source of water of excellent quality. Much of this water is stored in reservoirs, and when released during August and September, it improves the quality of the water at Trenton. These releases to augment low flow have the effect of narrowing the range of concentrations of dissolved constituents. In 1952 and 1962, 6 and 19 percent, respectively, of the drainage area above Trenton was regulated by reservoirs. After proposed construction, 60 percent will be regulated by 1975. Thus, it may be that the high concentrations of dissolved constituents observed in the 1945-61 period will not occur again. It is possible that the water quality observed during the period 1945-61 (dissolved solids 57-126 PPM 90 percent of the time, pH close to 7.0, hardness less than 86 PPM 95 percent of the time) is representative of what can be expected in the future, for a variety of hydrologic conditions were experienced in the 17-year period.

Lidar Observations of Atmospheric CO2 Column During 2014 Summer Flight Campaigns

NASA Technical Reports Server (NTRS)

Lin, Bing; Harrison, F. Wallace; Fan, Tai-Fang

2015-01-01

Advanced knowledge in atmospheric CO2 is critical in reducing large uncertainties in predictions of the Earth' future climate. Thus, Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) from space was recommended by the U.S. National Research Council to NASA. As part of the preparation for the ASCENDS mission, NASA Langley Research Center (LaRC) and Exelis, Inc. have been collaborating in development and demonstration of the Intensity-Modulated Continuous-Wave (IM-CW) lidar approach for measuring atmospheric CO2 column from space. Airborne laser absorption lidars such as the Multi-Functional Fiber Laser Lidar (MFLL) and ASCENDS CarbonHawk Experiment Simulator (ACES) operating in the 1.57 micron CO2 absorption band have been developed and tested to obtain precise atmospheric CO2 column measurements using integrated path differential absorption technique and to evaluate the potential of the space ASCENDS mission. This presentation reports the results of our lidar atmospheric CO2 column measurements from 2014 summer flight campaign. Analysis shows that for the 27 Aug OCO-2 under flight over northern California forest regions, significant variations of CO2 column approximately 2 ppm) in the lower troposphere have been observed, which may be a challenge for space measurements owing to complicated topographic condition, heterogeneity of surface reflection and difference in vegetation evapotranspiration. Compared to the observed 2011 summer CO2 drawdown (about 8 ppm) over mid-west, 2014 summer drawdown in the same region measured was much weak (approximately 3 ppm). The observed drawdown difference could be the results of the changes in both meteorological states and the phases of growing seasons. Individual lidar CO2 column measurements of 0.1-s integration were within 1-2 ppm of the CO2 estimates obtained from on-board in-situ sensors. For weak surface reflection conditions such as ocean surfaces, the 1- s integrated signal-to-noise ratio (SNR) of lidar measurements at 11 km altitude reached 376, which was equivalent to a 10-s CO2 error 0.33 ppm. For the entire processed 2014 summer flight campaign data, the mean differences between lidar remote sensed and in-situ estimated CO2 values were about -0.013 ppm. These results indicate that current laser absorption lidar approach could meet space measurement requirements for CO2 science goals.

Uranium-series coral ages from the US Atlantic Coastal Plain-the "80 ka problem" revisited

USGS Publications Warehouse

Wehmiller, J. F.; Simmons, K.R.; Cheng, H.; Edwards, R. Lawrence; Martin-McNaughton, J.; York, L.L.; Krantz, D.E.; Shen, C.-C.

2004-01-01

Uranium series coral ages for emergent units from the passive continental margin US Atlantic Coastal Plain (ACP) suggest sea level above present levels at the end of marine oxygen isotope stage (MIS) 5, contradicting age-elevation relations based on marine isotopic or coral reef models of ice equivalent sea level. We have reexamined this problem by obtaining high precision 230Th/238U and 231Pa/235U thermal ionization mass spectrometric ages for recently collected and carefully cleaned ACP corals, many in situ. We recognize samples that show no evidence for diagenesis on the basis of uranium isotopic composition and age concordance. Combining new and earlier data, among those ages close to or within the age range of MIS 5, over 85% cluster between 65 and 85 ka BP. Of the corals that we have analyzed, those that show the least evidence for diagenesis on the basis of uranium isotopic composition and age concordance have ages between 80 and 85 ka BP, consistent with a MIS 5a correlation. The units from which these samples have been collected are all emergent and have elevations within ???3-5m of those few units where early stage 5 (???125,000 ka BP) coral ages have been obtained. The ACP appears to record an unusual history of relative sea level throughout MIS 5, a history that is also apparent in the dated coral record for Bermuda. We speculate that this history is related to the regional (near-to intermediate-field) effects of ancestral Laurentide Ice sheets on last interglacial shorelines of the western North Atlantic. ?? 2004 Elsevier Ltd and INQUA. All rights reserved.

Evaluation on the use of cerium in the NBL Titrimetric Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zebrowski, J.P.; Orlowicz, G.J.; Johnson, K.D.

An alternative to potassium dichromate as titrant in the New Brunswick Laboratory Titrimetric Method for uranium analysis was sought since chromium in the waste makes disposal difficult. Substitution of a ceric-based titrant was statistically evaluated. Analysis of the data indicated statistically equivalent precisions for the two methods, but a significant overall bias of +0.035% for the ceric titrant procedure. The cause of the bias was investigated, alterations to the procedure were made, and a second statistical study was performed. This second study revealed no statistically significant bias, nor any analyst-to-analyst variation in the ceric titration procedure. A statistically significant day-to-daymore » variation was detected, but this was physically small (0.01 5%) and was only detected because of the within-day precision of the method. The added mean and standard deviation of the %RD for a single measurement was found to be 0.031%. A comparison with quality control blind dichromate titration data again indicated similar overall precision. Effects of ten elements on the ceric titration`s performance was determined. Co, Ti, Cu, Ni, Na, Mg, Gd, Zn, Cd, and Cr in previous work at NBL these impurities did not interfere with the potassium dichromate titrant. This study indicated similar results for the ceric titrant, with the exception of Ti. All the elements (excluding Ti and Cr), caused no statistically significant bias in uranium measurements at levels of 10 mg impurity per 20-40 mg uranium. The presence of Ti was found to cause a bias of {minus}0.05%; this is attributed to the presence of sulfate ions, resulting in precipitation of titanium sulfate and occlusion of uranium. A negative bias of 0.012% was also statistically observed in the samples containing chromium impurities.« less

Trace elements reconnaissance investigations in New Mexico and adjoining states in 1951

USGS Publications Warehouse

Bachman, George O.; Read, Charles B.

1952-01-01

In the summer and fall of 1951, a reconnaissance search was made in New Mexico and adjacent states for uranium in coal and carbonaceous shale, chiefly of Mesozoic age, and black marine shale of Paleozoic age. Tertiary volcanic rocks, considered to be a possible source for uranium in the coal and associated rocks, were examined where the volcanic rocks were near coal-bearing strata. Uranium in possibly commercial amounts was found at La Ventana Mesa, Sandoval County, New Mexico. Slightly uranifeous coal and carbonaceous shale were found near San Ysidro, Sandoval County, and on Beautiful Mountain, San Juan County, all in New Mexico, and at Keams Canyon, Navajo County, and near Tuba City, Coconino County, in Arizona. Except for La Ventana deposit, none appeared to be of economic importance at the time this report was written, but additional reconnaissance investigations have been underway this field season, in the area where the deposits occur. Marine black shale of Sevonian age was examined in Otero and Socorro Counties, New Mexico and Gila County, Arizona. Mississippian black shale in Socorro County and Pennsylvanian black shale in Taos County, New Mexico were also tested. Equivalent uranium content of samples of these shales did not exceed 0.004 percent. Rhyolitic tuff from the Mount Taylor region is slightly radioactive as is the Bandelier tuff in the Nacimiento region and in the Jemez Plateau. Volcanic rocks in plugs and dikes in the northern Chuska Mountains and to the north in New Mexico as well as in northeastern Arizona and southeastern Utah are slightly radioactive. Coal and carbonaceous rocks in the vicinity of these and similar intrusions are being examined.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakel, Allen J.; Conner, Cliff; Quigley, Kevin

One of the missions of the Reduced Enrichment for Research and Test Reactors (RERTR) program (and now the National Nuclear Security Administrations Material Management and Minimization program) is to facilitate the use of low enriched uranium (LEU) targets for 99Mo production. The conversion from highly enriched uranium (HEU) to LEU targets will require five to six times more uranium to produce an equivalent amount of 99Mo. The work discussed here addresses the technical challenges encountered in the treatment of uranyl nitrate hexahydrate (UNH)/nitric acid solutions remaining after the dissolution of LEU targets. Specifically, the focus of this work is themore » calcination of the uranium waste from 99Mo production using LEU foil targets and the Modified Cintichem Process. Work with our calciner system showed that high furnace temperature, a large vent tube, and a mechanical shield are beneficial for calciner operation. One- and two-step direct calcination processes were evaluated. The high-temperature one-step process led to contamination of the calciner system. The two-step direct calcination process operated stably and resulted in a relatively large amount of material in the calciner cup. Chemically assisted calcination using peroxide was rejected for further work due to the difficulty in handling the products. Chemically assisted calcination using formic acid was rejected due to unstable operation. Chemically assisted calcination using oxalic acid was recommended, although a better understanding of its chemistry is needed. Overall, this work showed that the two-step direct calcination and the in-cup oxalic acid processes are the best approaches for the treatment of the UNH/nitric acid waste solutions remaining from dissolution of LEU targets for 99Mo production.« less

Metal-rich fluid inclusions provide new insights into unconformity-related U deposits (Athabasca Basin and Basement, Canada)

NASA Astrophysics Data System (ADS)

Richard, Antonin; Cathelineau, Michel; Boiron, Marie-Christine; Mercadier, Julien; Banks, David A.; Cuney, Michel

2016-02-01

The Paleoproterozoic Athabasca Basin (Canada) hosts numerous giant unconformity-related uranium deposits. The scope of this study is to establish the pressure, temperature, and composition (P-T-X conditions) of the brines that circulated at the base of the Athabasca Basin and in its crystalline basement before, during and after UO2 deposition. These brines are commonly sampled as fluid inclusions in quartz- and dolomite-cementing veins and breccias associated with alteration and U mineralization. Microthermometry and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data from five deposits (Rabbit Lake, P-Patch, Eagle Point, Millennium, and Shea Creek) complement previously published data for the McArthur River deposit. In all of the deposits investigated, fluid inclusion salinity is between 25 and 40 wt.% NaCl equiv., with compositions displaying a continuum between a "NaCl-rich brine" end-member (Cl > Na > Ca > Mg > K) and a "CaCl2-rich brine" end-member (Cl > Ca ≈ Mg > Na > K). The CaCl2-rich brine has the highest salinity and shows evidence for halite saturation at the time of trapping. The continuum of compositions between the NaCl-rich brine and the CaCl2-rich brine end-members combined with P-T reconstructions suggest anisothermal mixing of the two brines (NaCl-rich brine, 180 ± 30 °C and 800 ± 400 bars; CaCl2-rich brine, 120 ± 30 °C and 600 ± 300 bars) that occurred under fluctuating pressure conditions (hydrostatic to supra-hydrostatic). However, because the two brines were U bearing and therefore oxidized, brine mixing was probably not the driving force for UO2 deposition. Several scenarios are put forward to account for the Cl-Na-Ca-Mg-K composition of the brines, involving combinations of seawater evaporation, halite dissolution, mixing with a halite-dissolution brine, Mg/Ca exchange by dolomitization, Na/Ca exchange by albitization of plagioclase, Na/K exchange by albitization of K-feldspar, and Mg loss by Mg-rich alteration. Finally, the metal concentrations in the NaCl-rich and CaCl2-rich brines are among the highest recorded compared to present-day sedimentary formation waters and fluid inclusions from basin-hosted base metal deposits (up to 600 ppm U, 3000 ppm Mn, 4000 ppm Zn, 6000 ppm Cu, 8000 ppm Pb, and 10,000 ppm Fe). The CaCl2-rich brine carries up to one order of magnitude more metal than the NaCl-rich brine. Though the exact origin of major cations and metals of the two brines remains uncertain, their contrasting compositions indicate that the two brines had distinct flow paths and fluid-rock interactions. Large-scale circulation of the brines in the Athabasca Basin and Basement was therefore a key parameter for metal mobility (including U) and formation of unconformity-related U deposits.

Evaluation of kinetic phosphorescence analysis for the determination of uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croatto, P.V.; Frank, I.W.; Johnson, K.D.

In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11more » offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density matrix (1 M HNO{sub 3}). A statistical evaluation of the determination of uranium using kinetic phosphorimetry is described in this report, along with a discussion of the method, and an evaluation of the use of plastic versus quartz cuvettes. Measurement with a precision of {+-} 3--4% relative standard deviation (RSD) and an accuracy of better than {+-} 2% relative difference (RD) are obtained in the 0.0006 to 5 {micro}g U/g-solution range. The instrument detection limit is 0.04 ppb (4 x 10{sup {minus}5} {micro}g U/g solution) using quartz cells, and 0.11 ppb (11 x 10{sup {minus}5} {micro}g U/g solution) using disposable methacrylate cuvettes.« less

Evaluation of low-cost electro-chemical sensors for environmental monitoring of ozone, nitrogen dioxide, and carbon monoxide.

PubMed

Afshar-Mohajer, Nima; Zuidema, Christopher; Sousan, Sinan; Hallett, Laura; Tatum, Marcus; Rule, Ana M; Thomas, Geb; Peters, Thomas M; Koehler, Kirsten

2018-02-01

Development of an air quality monitoring network with high spatio-temporal resolution requires installation of a large number of air pollutant monitors. However, state-of-the-art monitors are costly and may not be compatible with wireless data logging systems. In this study, low-cost electro-chemical sensors manufactured by Alphasense Ltd. for detection of CO and oxidative gases (predominantly O 3 and NO 2 ) were evaluated. The voltages from three oxidative gas sensors and three CO sensors were recorded every 2.5 sec when exposed to controlled gas concentrations in a 0.125-m 3 acrylic glass chamber. Electro-chemical sensors for detection of oxidative gases demonstrated sensitivity to both NO 2 and O 3 with similar voltages recorded when exposed to equivalent environmental concentrations of NO 2 or O 3 gases, when evaluated separately. There was a strong linear relationship between the recorded voltages and target concentrations of oxidative gases (R 2 > 0.98) over a wide range of concentrations. Although a strong linear relationship was also observed for CO concentrations below 12 ppm, a saturation effect was observed wherein the voltage only changes minimally for higher CO concentrations (12-50 ppm). The nonlinear behavior of the CO sensors implied their unsuitability for environments where high CO concentrations are expected. Using a manufacturer-supplied shroud, sensors were tested at 2 different flow rates (0.25 and 0.5 Lpm) to mimic field calibration of the sensors with zero air and a span gas concentration (2 ppm NO2 or 15 ppm CO). As with all electrochemical sensors, the tested devices were subject to drift with a bias up to 20% after 9 months of continuous operation. Alphasense CO sensors were found to be a proper choice for occupational and environmental CO monitoring with maximum concentration of 12 ppm, especially due to the field-ready calibration capability. Alphasense oxidative gas sensors are usable only if it is valuable to know the sum of the NO 2 and O 3 concentrations.

Skin thickness effects on in vivo LXRF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preiss, I.L.; Washington, W. II

The analysis of lead concentration in bone utilizing LXRF can be adversely effected by overlying issue. A quantitative measure of the attenuation of the 10.5 keV Pb L a x-ray signal by skin and skin equivalent plastic has been conducted. Concentration ranges in plaster of Paris and goat bone from 7 to 90 ppm with attenuators of Lucite{reg_sign} and pig skin were examined. It is concluded that no quantitative or semi quantitative analysis can be achieved if overlying sue thickness exceeds 3 mm for Ph concentrations of less than 30 porn Ph in bone.

Effect of quantity and route of administration of manganese monoxide on feed intake and serum manganese in ruminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, J.R.; Ammerman, C.B.; Henry, P.R.

1985-02-01

The experiment investigated effects of high quantities of manganese and route of administration (diet versus capsule-dosed) on feed intake and blood characteristics in sheep. Twenty-four Florida native or Florida native by St. Croix crossbred wethers, 47 kg initially, were assigned randomly to eight treatments including basal diet supplemented with 0, 3000, 6000, or 9000 ppm manganese as a reagent grade manganese monoxide or basal diet plus gelatin capsules containing the equivalent of 0, 3000, 6000, or 9000 ppm manganese based on intake of the previous day. Three sheep per treatment were provided feed and tap water for ad libitum intake.more » Sheep were fed basal diet for 7 days followed by a 21-day experimental period, then placed back on the basal diet for 7 days. Average daily feed intake was reduced by increasing supplemental manganese, regardless of route. Animals dosed by capsule consumed less feed than those administered manganese in the diet. Serum manganese increased as manganese supplementation increased, but route of administration had no effect.« less

Advanced PEFC development for fuel cell powered vehicles

NASA Astrophysics Data System (ADS)

Kawatsu, Shigeyuki

Vehicles equipped with fuel cells have been developed with much progress. Outcomes of such development efforts include a Toyota fuel cell electric vehicle (FCEV) using hydrogen as the fuel which was developed and introduced in 1996, followed by another Toyota FCEV using methanol as the fuel, developed and introduced in 1997. In those Toyota FCEVs, a fuel cell system is installed under the floor of each RAV4L, to sports utility vehicle. It has been found that the CO concentration in the reformed gas of methanol reformer can be reduced to 100 ppm in wide ranges of catalyst temperature and gas flow rate, by using the ruthenium (Ru) catalyst as the CO selective oxidizer, instead of the platinum (Pt) catalyst known from some time ago. It has been also found that a fuel cell performance equivalent to that with pure hydrogen can be ensured even in the reformed gas with the carbon monoxide (CO) concentration of 100 ppm, by using the Pt-Ru (platinum ruthenium alloy) electrocatalyst as the anode electrocatalyst of a polymer electrolyte fuel cell (PEFC), instead of the Pt electrocatalyst known from some time ago.

Consequences of slow growth for 230Th/U dating of Quaternary opals, Yucca Mountain, NV, USA

USGS Publications Warehouse

Neymark, L.A.; Paces, J.B.

2000-01-01

Thermal ionization mass-spectrometry 234U/238U and 230Th/238U data are reported for uranium-rich opals coating fractures and cavities within the silicic tuffs forming Yucca Mountain, NV, the potential site of a high-level radioactive waste repository. High uranium concentrations (up to 207 ppm) and extremely high 230Th/232Th activity ratios (up to about 106) make microsamples of these opals suitable for precise 230Th/U dating. Conventional 230Th/U ages range from 40 to greater than 600 ka, and initial 234U/238U activity ratios between 1.03 and 8.2. Isotopic evidence indicates that the opals have not experienced uranium mobility; however, wide variations in apparent ages and initial 234U/238U ratios for separate subsamples of the same outermost mineral surfaces, positive correlation between ages and sample weights, and negative correlation between 230Th/U ages and calculated initial 234U/238U are inconsistent with the assumption that all minerals in a given subsample was deposited instantaneously. The data are more consistent with a conceptual model of continuous deposition where secondary mineral growth has occurred at a constant, slow rate up to the present. This model assumes that individual subsamples represent mixtures of older and younger material, and that calculations using the resulting isotope ratios reflect an average age. Ages calculated using the continuous-deposition model for opals imply average mineral growth rates of less than 5 mm/m.y. The model of continuous deposition also predicts discordance between ages obtained using different radiometric methods for the same subsample. Differences in half-lives will result in younger apparent ages for the shorter-lived isotope due to the greater influence of younger materials continuously added to mineral surfaces. Discordant 14C, 230Th/U and U-Pb ages obtained from outermost mineral surfaces at Yucca Mountain support this model. (C) 2000 Elsevier Science B.V. All rights reserved.

Parallel Processing of Broad-Band PPM Signals

NASA Technical Reports Server (NTRS)

Gray, Andrew; Kang, Edward; Lay, Norman; Vilnrotter, Victor; Srinivasan, Meera; Lee, Clement

2010-01-01

A parallel-processing algorithm and a hardware architecture to implement the algorithm have been devised for timeslot synchronization in the reception of pulse-position-modulated (PPM) optical or radio signals. As in the cases of some prior algorithms and architectures for parallel, discrete-time, digital processing of signals other than PPM, an incoming broadband signal is divided into multiple parallel narrower-band signals by means of sub-sampling and filtering. The number of parallel streams is chosen so that the frequency content of the narrower-band signals is low enough to enable processing by relatively-low speed complementary metal oxide semiconductor (CMOS) electronic circuitry. The algorithm and architecture are intended to satisfy requirements for time-varying time-slot synchronization and post-detection filtering, with correction of timing errors independent of estimation of timing errors. They are also intended to afford flexibility for dynamic reconfiguration and upgrading. The architecture is implemented in a reconfigurable CMOS processor in the form of a field-programmable gate array. The algorithm and its hardware implementation incorporate three separate time-varying filter banks for three distinct functions: correction of sub-sample timing errors, post-detection filtering, and post-detection estimation of timing errors. The design of the filter bank for correction of timing errors, the method of estimating timing errors, and the design of a feedback-loop filter are governed by a host of parameters, the most critical one, with regard to processing very broadband signals with CMOS hardware, being the number of parallel streams (equivalently, the rate-reduction parameter).

Direct assignment of the cysteinyl, the slowly exchangeable, and the aromatic ring H nuclear magnetic resonances in clostridial-type ferredoxins. [Clostridium acidi-urici, C. pasteurianum, C. perfringens, Peptococcus aerogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Packer, E.L.; Sweeney, W.V.; Rabinowitz, J.C.

1977-04-10

We have directly assigned the /sup 1/H NMR corresponding to the cysteinyl protons, the slowly exchangeable protons, and the aromatic ring protons in the /sup 1/H NMR spectrum of Clostridium acidi-urici ferredoxin by isotopic labeling and /sup 13/C NMR decoupling techniques. We also show that the resonance pattern in the 8- to 20-ppM (from 2,2-dimethyl-2-sialapentanesulfonic acid) region of the /sup 1/H NMR spectra of oxidized Clostridium acidi-urici, Clostridium pasteurianum, Clostridium perfringens, and Peptococcus aerogenes ferredoxins are very similar, and we assign the resonances in this region by analogy with the spectrum of C. acidi-urici ferredoxin. The /sup 1/H NMR spectramore » of the ..beta.. protons of the cysteinyl residues of these ferredoxins differ, however, from the /sup 1/H NMR spectra of equivalent ..beta.. protons of the methylene carbon atoms bonded via a sulfur atom to (4Fe-4S) clusters in synthetic inorganic analogues. In the spectra of the synthetic compounds, the ..beta.. protons appear as a single resonance shifted 10 ppM from its unbonded reference position. In the spectra of oxidized clostridial ferredoxins, the cysteinyl ..beta.. protons appear as a series of at least eight resolved resonances with shifts that range from 6 to 14 ppM, relative to the free amino acid resonance position.« less

Protein Oxidation and Sensory Quality of Brine-Injected Pork Loins Added Ascorbate or Extracts of Green Tea or Maté during Chill-Storage in High-Oxygen Modified Atmosphere

PubMed Central

Tørngren, Mari Ann

2018-01-01

Background: Ascorbate is often applied to enhance stability and robustness of brine-injected pork chops sold for retail, but may affect protein oxidation, while plant extracts are potential substitutes. Methods: Brine-injected pork chops (weight-gain ~12%, NaCl ~0.9%) prepared with ascorbate (225 ppm), green tea extract (25 ppm gallic acid equivalents (GAE)), or maté extract (25 ppm GAE) stored (5 °C, seven days) in high-oxygen atmosphere packaging (MAP: 80% O2 and 20% CO2) were analyzed for color changes, sensory quality, and protein oxidation compared to a control without antioxidant. Results: No significant differences were observed for green tea and maté extracts as compared to ascorbate when evaluated based on lipid oxidation derived off-flavors, except for stale flavor, which maté significantly reduced. All treatments increased the level of the protein oxidation product, α-aminoadipic semialdehyde as compared to the control, and ascorbate was further found to increase thiol loss and protein cross-linking, with a concomitant decrease in the sensory perceived tenderness. Conclusions: Green tea and maté were found to equally protect against lipid oxidation derived off-flavors, and maté showed less prooxidative activity towards proteins as compared to ascorbate, resulting in more tender meat. Maté is a valuable substitute for ascorbate in brine-injected pork chops. PMID:29342928

The distribution of H2O between silicate melt and nominally anhydrous peridotite and the onset of hydrous melting in the deep upper mantle

NASA Astrophysics Data System (ADS)

Novella, Davide; Frost, Daniel J.; Hauri, Erik H.; Bureau, Helene; Raepsaet, Caroline; Roberge, Mathilde

2014-08-01

The partitioning of H2O between a mantle peridotite assemblage and low degree hydrous melt has been investigated at 6 GPa (corresponding to ∼180 km depth) at a temperature of 1400 °C. Peridotite mineral phases were analysed from 6 melting experiments performed in a natural chemical system. The experiments contained ∼80 wt% of a low degree hydrous melt that was obtained through a series of experiments where the melt composition was iteratively adjusted until saturation with the appropriate peridotite assemblage was achieved. The melt is fluid-undersaturated at the conditions of the experiment. Ion microprobe measurements of the mineral phases indicate olivine H2O concentrations of 434±61 ppm wt and average clinopyroxene (cpx) concentrations of 1268±173 ppm wt H2O. Orthopyroxene (opx) and garnet contain 700±46 ppm wt and 347±83 ppm wt H2O, respectively. The H2O content of the hydrous melts was determined by mass balance to be 11±0.5 wt% H2O. H2O partition coefficients between minerals and melt (DH2Omin/melt=XH2Omin/XH2Omelt) are 0.0040±0.0006 for olivine, 0.0064±0.0004 for opx, 0.0115±0.0016 for cpx and 0.0032±0.0008 for garnet. Using the determined H2O partition coefficients the onset and extent of melting at conditions equivalent to 180 km below mid-ocean ridges was determined as a function of mantle H2O content. Current estimates for the H2O content of the depleted mantle (50-200 ppm wt H2O) are insufficient to induce mantle melting at this depth, which requires ∼700 ppm wt H2O to produce 0.1% melting and 1600 ppm wt H2O for 1% melting, along an adiabat with a potential temperature of 1327 °C. Melting can occur at these conditions within the mantle source of ocean island basalts, which are estimated to contain up to 900 ppm wt H2O. If adiabatic temperatures are 200 °C higher within such plume related sources, then melt fractions of over 1% can be reached at 180 km depth. In addition, a model for the distribution of H2O between peridotite mineral phases as a function of depth and at H2O-undersaturated conditions is constructed. The model indicates that for a fixed mantle composition containing 150 ppm wt H2O, the olivine H2O content will increase with depth solely due to changes in inter-phase partitioning and modal proportions of minerals. The change in the olivine H2O concentration with depth corresponds to proposed changes in the dominant olivine slip system for deformation by dislocation creep, that might provide an explanation for the reduction in seismic anisotropy observed at depths >200 km.

Isotopic determination of uranium in soil by laser induced breakdown spectroscopy

DOE PAGES

Chan, George C. -Y.; Choi, Inhee; Mao, Xianglei; ...

2016-03-26

Laser-induced breakdown spectroscopy (LIBS) operated under ambient pressure has been evaluated for isotopic analysis of uranium in real-world samples such as soil, with U concentrations in the single digit percentage levels. The study addresses the requirements for spectral decomposition of 235U and 238U atomic emission peaks that are only partially resolved. Although non-linear least-square fitting algorithms are typically able to locate the optimal combination of fitting parameters that best describes the experimental spectrum even when all fitting parameters are treated as free independent variables, the analytical results of such an unconstrained free-parameter approach are ambiguous. In this work, five spectralmore » decomposition algorithms were examined, with different known physical properties (e.g., isotopic splitting, hyperfine structure) of the spectral lines sequentially incorporated into the candidate algorithms as constraints. It was found that incorporation of such spectral-line constraints into the decomposition algorithm is essential for the best isotopic analysis. The isotopic abundance of 235U was determined from a simple two-component Lorentzian fit on the U II 424.437 nm spectral profile. For six replicate measurements, each with only fifteen laser shots, on a soil sample with U concentration at 1.1% w/w, the determined 235U isotopic abundance was (64.6 ± 4.8)%, and agreed well with the certified value of 64.4%. Another studied U line - U I 682.691 nm possesses hyperfine structure that is comparatively broad and at a significant fraction as the isotopic shift. Thus, 235U isotopic analysis with this U I line was performed with spectral decomposition involving individual hyperfine components. For the soil sample with 1.1% w/w U, the determined 235U isotopic abundance was (60.9 ± 2.0)%, which exhibited a relative bias about 6% from the certified value. The bias was attributed to the spectral resolution of our measurement system - the measured line width for this U I line was larger than its isotopic splitting. In conclusion, although not the best emission line for isotopic analysis, this U I emission line is sensitive for element analysis with a detection limit of 500 ppm U in the soil matrix; the detection limit for the U II 424.437 nm line was 2000 ppm.« less

Geothermal potential of Caledonian granites in Ireland and the Isle of Man: Implications from hydrothermal alteration

NASA Astrophysics Data System (ADS)

Fritschle, Tobias; Daly, J. Stephen; Whitehouse, Martin J.; Buhre, Stephan; McConnell, Brian; The Iretherm Team

2015-04-01

Ordovician to Devonian (Caledonian) granites are common in the Iapetus Suture Zone (ISZ) in Ireland and Britain. Some of these, e.g., the buried Kentstown and Glenamaddy granites, are situated beneath Upper Palaeozoic sedimentary basins, and hence are potential geothermal targets. Numerous granites of similar age and related origin (Fritschle et al., 2014) are exposed astride the ISZ. They are considered to be analogous to the buried ones, and their geochemical characteristics are used as a proxy for the buried granites as samples from deep drilling are naturally limited. The whole-rock geochemistry of nine granite intrusions (71 samples, including both hydrothermally altered and unaltered samples) varies significantly, but with no obvious geographical control. The granites are S- and I-Types with ASI (Aluminium Saturation Index) between 0.7 - 1.4. Average heat production rates range from 1.4 μW/m³ for the Leinster Granite to 4.9 μW/m³ for the Drogheda Granite (Fritschle et al., 2015). The heat-producing elements uranium (U), thorium (Th) and potassium (K) and calculated heat production rates generally correlate positively with niobium and rubidium concentrations. However, S-Type compared to I-Type granites show elevated abundances in rubidium (>130 ppm) and usually have a lower Th/U ratio. Altered samples tend to have a higher Th/U ratio compared to unaltered ones. Within individual plutons trends of decreasing heat production rates with increasing Th/U ratios were observed. This trend is attributed to the hydrothermal redistribution of the mobile heat-producing element uranium. This is also implied by uranium-enrichment in hydrothermally generated Ca and Si-veinlets. Metasomatic processes such as hydrothermal alteration appear capable of significantly redistributing mobile elements such as uranium. Hence, these processes may act as a major mechanism controlling the granite's heat production budget, often shaping a pluton's geothermal exploitation potential. Fritschle, T., Daly, J.S., Whitehouse, M.J., Buhre, S., McConnell, B., 2015. Geothermal potential of Caledonian granites astride the Iapetus Suture Zone in Ireland and the Isle of Man - Implications for EGS prospectivity. Proceedings World Geothermal Congress 2015, in press. Fritschle, T., Daly, J.S., Whitehouse, M.J., McConnell, B., Buhre, S., 2014. Zircon geochronology and Hf-O isotope geochemistry from granites in the Iapetus Suture Zone in Ireland and the Isle of Man. Geophysical Research Abstracts 16, EGU-2014-801.

Polyoxometal cations within polyoxometalate anions. Seven-coordinate uranium and zirconium heteroatom groups in [(UO2)12(μ3-O)4(μ2-H2O)12(P2W15O56)4]32- and [Zr4(μ3-O)2(μ2-OH)2(H2O)4 (P2W16O59)2]14-

NASA Astrophysics Data System (ADS)

Gaunt, Andrew J.; May, Iain; Collison, David; Travis Holman, K.; Pope, Michael T.

2003-08-01

Two new composite polyoxotungstate anions with unprecedented structural features, [(UO2)12(μ3-O)4(μ2-H2O)12(P2W15O56)4]32- (1) and [Zr4(μ3-O)2(μ2-OH)2(H2O)4 (P2W16O59)2]14- (2) contain polyoxo-uranium and -zirconium clusters as bridging units. The anions are synthesized by reaction of Na12[P2W15O56] with solutions of UO2(NO3)2 and ZrCl4. The structure of 1 in the sodium salt contains four [P2W15O56]12- anions assembled into an overall tetrahedral cluster by means of trigonal bridging groups formed by three equatorial-edge-shared UO7 pentagonal bipyramids. The structure of anion 2 consists of a centrosymmetric assembly of two [P2W16O59]12- anions linked by a {Zr4O2(OH)2(H2O)4}10+ cluster. Both complexes in solution yield the expected two-line 31P-NMR spectra with chemical shifts of -2.95, -13.58 and -6.45, -13.69 ppm, respectively.

Development of RF plasma simulations of in-reactor tests of small models of the nuclear light bulb fuel region

NASA Technical Reports Server (NTRS)

Roman, W. C.; Jaminet, J. F.

1972-01-01

Experiments were conducted to develop test configurations and technology necessary to simulate the thermal environment and fuel region expected to exist in in-reactor tests of small models of nuclear light bulb configurations. Particular emphasis was directed at rf plasma tests of approximately full-scale models of an in-reactor cell suitable for tests in Los Alamos Scientific Laboratory's Nuclear Furnace. The in-reactor tests will involve vortex-stabilized fissioning uranium plasmas of approximately 200-kW power, 500-atm pressure and equivalent black-body radiating temperatures between 3220 and 3510 K.

Determination of uranium and thorium using gamma spectrometry: a pilot study

NASA Astrophysics Data System (ADS)

Olivares, D. M. M.; Koch, E. S.; Guevara, M. V. M.; Velasco, F. G.

2018-03-01

This paper presents the results of a pilot experiment aimed at standardizing procedures for the CPqCTR/UESC Gamma Spectrometry Laboratory (LEG) for the quantification of natural radioactive elements in solid environmental samples. The concentrations of 238U, 232Th and 40K in two sediment matrix belonging to the Caetité region were determined, by using the absolute method with uncertainties about 5%. The results were obtained using gamma spectrometry with a high-resolution p-type HPGe detector. As a closure, the absorbed dose, radium equivalent activity and the annual effective dose were calculated.

Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

NASA Astrophysics Data System (ADS)

Zia, Asif I.; Mohd Syaifudin, A. R.; Mukhopadhyay, S. C.; Yu, P. L.; Al-Bahadly, I. H.; Gooneratne, Chinthaka P.; Kosel, Jǘrgen; Liao, Tai-Shan

2013-06-01

Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle's equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

Gas core reactors for actinide transmutation. [uranium hexafluoride

NASA Technical Reports Server (NTRS)

Clement, J. D.; Rust, J. H.; Wan, P. T.; Chow, S.

1979-01-01

The preliminary design of a uranium hexafluoride actinide transmutation reactor to convert long-lived actinide wastes to shorter-lived fission product wastes was analyzed. It is shown that externally moderated gas core reactors are ideal radiators. They provide an abundant supply of thermal neutrons and are insensitive to composition changes in the blanket. For the present reactor, an initial load of 6 metric tons of actinides is loaded. This is equivalent to the quantity produced by 300 LWR-years of operation. At the beginning, the core produces 2000 MWt while the blanket generates only 239 MWt. After four years of irradiation, the actinide mass is reduced to 3.9 metric tonnes. During this time, the blanket is becoming more fissile and its power rapidly approaches 1600 MWt. At the end of four years, continuous refueling of actinides is carried out and the actinide mass is held constant. Equilibrium is essentially achieved at the end of eight years. At equilibrium, the core is producing 1400 MWt and the blanket 1600 MWt. At this power level, the actinide destruction rate is equal to the production rate from 32 LWRs.

Comparison of femtosecond and nanosecond laser ablation inductively coupled plasma mass spectrometry for uranium isotopic measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Havrilla, George Joseph; McIntosh, Kathryn Gallagher; Judge, Elizabeth

2016-10-20

Feasibility tests were conducted using femtosecond and nanosecond laser ablation inductively coupled plasma mass spectrometry for rapid uranium isotopic measurements. The samples used in this study consisted of a range of pg quantities of known 235/238 U solutions as dried spot residues of 300 pL drops on silicon substrates. The samples spanned the following enrichments of 235U: 0.5, 1.5, 2, 3, and 15.1%. In this direct comparison using these particular samples both pulse durations demonstrated near equivalent data can be produced on either system with respect to accuracy and precision. There is no question that either LA-ICP-MS method offers themore » potential for rapid, accurate and precise isotopic measurements of U10Mo materials whether DU, LEU or HEU. The LA-ICP-MS equipment used for this work is commercially available. The program is in the process of validating this work for large samples using center samples strips from Y-12 MP-1 LEU-Mo Casting #1.« less

Alternative nuclear technologies

NASA Astrophysics Data System (ADS)

Schubert, E.

1981-10-01

The lead times required to develop a select group of nuclear fission reactor types and fuel cycles to the point of readiness for full commercialization are compared. Along with lead times, fuel material requirements and comparative costs of producing electric power were estimated. A conservative approach and consistent criteria for all systems were used in estimates of the steps required and the times involved in developing each technology. The impact of the inevitable exhaustion of the low- or reasonable-cost uranium reserves in the United States on the desirability of completing the breeder reactor program, with its favorable long-term result on fission fuel supplies, is discussed. The long times projected to bring the most advanced alternative converter reactor technologies the heavy water reactor and the high-temperature gas-cooled reactor into commercial deployment when compared to the time projected to bring the breeder reactor into equivalent status suggest that the country's best choice is to develop the breeder. The perceived diversion-proliferation problems with the uranium plutonium fuel cycle have workable solutions that can be developed which will enable the use of those materials at substantially reduced levels of diversion risk.

Future Scenarios for Fission Based Reactors

NASA Astrophysics Data System (ADS)

David, S.

2005-04-01

The coming century will see the exhaustion of standard fossil fuels, coal, gas and oil, which today represent 75% of the world energy production. Moreover, their use will have caused large-scale emission of greenhouse gases (GEG), and induced global climate change. This problem is exacerbated by a growing world energy demand. In this context, nuclear power is the only GEG-free energy source available today capable of responding significantly to this demand. Some scenarios consider a nuclear energy production of around 5 Gtoe in 2050, wich would represent a 20% share of the world energy supply. Present reactors generate energy from the fission of U-235 and require around 200 tons of natural Uranium to produce 1GWe.y of energy, equivalent to the fission of one ton of fissile material. In a scenario of a significant increase in nuclear energy generation, these standard reactors will consume the whole of the world's estimated Uranium reserves in a few decades. However, natural Uranium or Thorium ore, wich are not themselves fissile, can produce a fissile material after a neutron capture ( 239Pu and 233U respectively). In a breeder reactor, the mass of fissile material remains constant, and the fertile ore is the only material to be consumed. In this case, only 1 ton of natural ore is needed to produce 1GWe.y. Thus, the breeding concept allows optimal use of fertile ore and development of sustainable nuclear energy production for several thousand years into the future. Different sustainable nuclear reactor concepts are studied in the international forum "generation IV". Different types of coolant (Na, Pb and He) are studied for fast breeder reactors based on the Uranium cycle. The thermal Thorium cycle requires the use of a liquid fuel, which can be reprocessed online in order to extract the neutron poisons. This paper presents these different sustainable reactors, based on the Uranium or Thorium fuel cycles and will compare the different options in term of fissile inventory, capacity to be deployed, induced radiotoxicities, and R&D efforts.

Redox bias in loss of ignition moisture measurement for relatively pure plutonium-bearing oxide materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eller, P. G.; Stakebake, J. L.; Cooper, T. D.

2001-01-01

This paper evaluates potential analytical bias in application of the Loss on Ignition (LOI) technique for moisture measurement to relatively pure (plutonium assay of 80 wt.% or higher) oxides containing uranium that have been stabilized according to stabilization and storage standard DOE-STD-3013-2000 (STD-3013). An immediate application is to Rocky Flats (RF) materials derived from highgrade metal hydriding separations subsequently treated by multiple calcination cycles. Specifically evaluated are weight changes due to oxidatiodreduction of multivalent impurity oxides that could mask true moisture equivalent content measurement. Process knowledge and characterization of materials representing complex-wide materials to be stabilized and packaged according tomore » STD-3013, and particularly for the immediate RF target stream, indicate that oxides of uranium, iron and gallium are the only potential multivalent constituents expected to be present above 0.5 wt.%. The evaluation shows that of these constituents, with few exceptions, only uranium oxides can be present at a sufficient level to produce weight gain biases significant with respect to the LO1 stability test. In general, these formerly high-value, high-actinide content materials are reliably identifiable by process knowledge and measurement. Si&icant bias also requires that UO1 components remain largely unoxidized after calcination and are largely converted to U30s clsning LO1 testing at only slightly higher temperatures. Based on wellestablished literature, it is judged unlikely that this set of conditions will be realized in practice. We conclude that it is very likely that LO1 weight gain bias will be small for the immediate target RF oxide materials containing greater than 80 wt.% plutonium plus a much smaller uranium content. Recommended tests are in progress to confum these expectations and to provide a more authoritative basis for bounding LO1 oxidatiodreduction biases. LO1 bias evaluation is more difficult for lower purity materials and for fuel-type uranium-plutonium oxides. However, even in these cases testing may show that bias effects are manageable.« less

Correlation between the oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

NASA Astrophysics Data System (ADS)

Park, Sang-Yoon; Lee, Myung-Ho; Jeong, Yong-Hwan; Jung, Youn-Ho

2004-12-01

The correlation between the oxide impedance and corrosion behavior of two series of Zr-Nb-Sn-Fe-Cu alloys was evaluated. Corrosion tests were performed in a 70 ppm LiOH aqueous solution at 360°C for 300 days. The results of the corrosion tests revealed that the corrosion behavior of the alloys depended on the Nb and Sn content. The impedance characteristics for the pre- and post-transition oxide layers formed on the surface of the alloys were investigated in sulfuric acid at room temperature. From the results, a pertinent equivalent circuit model was preferably established, explaining the properties of double oxide layers. The impedance of the oxide layers correlated with the corrosion behavior; better corrosion resistance always showed higher electric resistance for the inner layers. It is thus concluded that a pertinent equivalent circuit model would be useful for evaluating the long-term corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys.

Household air pollution following replacement of traditional open fire with an improved rocket type cookstove.

PubMed

Ochieng, Caroline; Vardoulakis, Sotiris; Tonne, Cathryn

2017-02-15

Cooking with biomass fuel is an important source of household air pollution (HAP) in developing countries, and a leading risk factor for ill-health. Although various designs of "improved cookstoves" (ICS) have been promoted as HAP interventions in these settings, few of them have undergone in-field evaluation, partly due to the challenge of conducting field measurements in remote settings. In this study we assessed the change in carbon monoxide (CO) exposure following the replacement of the traditional three-stone stove with a popular ICS in 49 homes in Western Kenya. We also assessed the suitability of using kitchen CO as a proxy for kitchen PM 2.5 . Reduction in 48h mean kitchen CO was 3.1ppm (95% CI: -8.1, 1.8) and in personal CO was 0.9ppm (95% CI: -4.3, 2.6) following stove replacements. Overall, 48-h kitchen and personal CO exposures were lower after stove replacement (28% and 12%, respectively) but with wide confidence intervals that also suggested possible increases in exposure. There were statistically significant reductions in peak kitchen and personal CO concentrations represented by the 8-h 95th percentile: reductions of 26.1ppm (95% CI: -44.6, -7.6) and 8.0ppm (95% CI: -12.2, -3.8), respectively. This is equivalent to 53% reduction in kitchen CO and 39% reduction in personal CO. We found good correlation between kitchen CO and PM 2.5 concentrations overall (r=0.73, n=33 over averaging periods approximating 1day), which varied by time of day and exposure setting. These variations limit the applicability of CO as a proxy measure for PM 2.5 concentrations. A combination of interventions, including better designed stoves, improved ventilation and cleaner fuels, may be needed to reduce HAP to levels that are likely to improve health. Copyright © 2016. Published by Elsevier B.V.

Disposition of inhaled 1-chloro-2-propanol in F344/N rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bond, J.A.; Birnbaum, L.S.; Dahl, A.R.

1988-09-30

Propylene chlorohydrins, of which 1-chloro-2-propanol (1-CP) is a constituent, used as intermediates in the manufacture of propylene oxide and have been identified as potential air pollutants. The objective of these studies was to determine whether changes in the inhaled exposure concentration would affect the disposition of 1-CP in rats. In addition, experiments were conducted to identify the carbon atom of 1-CP that is metabolized to CO2. Rats were exposed nose-only to (14C)1-CP for 6 hr to 8.3 +/- 1.0 ppm (26.1 +/- 3.2 micrograms/liter air) or 77 +/- 4 ppm (245 +/- 13 micrograms/liter air) (mean +/- SE). There weremore » two major routes of elimination of 14C, urinary and exhalation of CO2, which together accounted for about 80% of the total 14C in excreta and carcass. Half-times for elimination of 14C in urine as 14CO2 were between 3 and 7 hr with no effect of exposure concentration on the elimination half-times for either route. After the end of exposure, kidneys, livers, trachea, and nasal turbinates contained high concentrations of (14C)1-CP equivalents at both exposure concentrations (30-50 nmol 14C/g tissue for the 8 ppm exposure level and 200-350 nmol 14C/g tissue for the 80 ppm exposure level). Elimination of 14C from tissues was biphasic with about 50% of the material in a tissue being rapidly eliminated with a half-time of 1 to 3 hr and the remaining material slowly eliminated with a half-time of 40 to 80 hr. There was no effect of exposure concentration on elimination half-times in tissues. Major metabolites detected in urine and tissues (liver, kidney, and lung) were N-acetyl-S-(hydroxypropyl)cysteine and/or S-(2-hydroxypropyl)-cysteine. Little unmetabolized 1-CP (less than 1%) was detected in analyzed tissues or urine.« less

Surgical relocation of the papillary muscles in functional ischemic mitral regurgitation: what are the forces of the relocation stitches acting on the myocardium?

PubMed

Jensen, Henrik; Jensen, Morten O; Vind-Kezunovic, Stefan; Vestergaard, Rikke; Ringgaard, Steffen; Smerup, Morten H; Hønge, Jesper L; Hasenkam, J Michael; Nielsen, Sten L

2013-07-01

In patients with chronic functional ischemic mitral regurgitation (FIMR), papillary muscle relocation has the potential to induce reverse left ventricular remodeling. However, in order to optimize function and durability, the forces imposed on the left ventricular myocardium by papillary muscle relocation should be assessed. Eight pigs with FIMR were subjected to down-sized ring annuloplasty in combination with relocation of the anterior (5 mm) and posterior (15 mm) papillary muscles towards the respective trigone. Papillary muscle relocation was obtained by a 2-0 expanded polytetrafluoroethylene stitch fixed to the trigone, exteriorized through the myocardium overlying the papillary muscle, and fixed to an epicardial disc. Tension in these stitches was measured at a systolic blood pressure > 80 mmHg using a custom-made sliding caliper with a strain gauge mounted in line. This allowed assessment of the cyclic change from minimal diastolic to maximum systolic papillary muscle relocation stitch tension. Maximum cyclic change in the posterior papillary muscle (PPM) stitch tension was 1.1 N at 15 mm relocation. In comparison, the anterior papillary muscle (APM) tension was increased to a maximum of 1.4 N with only 5 mm relocation. Surprisingly, during each step of isolated PPM relocation, the APM stitch tension increased concomitantly, but in contrast APM relocation did not influence the magnitude of PPM stitch tension. There was no statistically significant difference between cyclic changes in APM and PPM stitch tension at any step of relocation. Papillary muscle relocation using stitches attached between epicardial discs and respective trigones induced a cyclic change in papillary muscle relocation stitch tension of 1.1-1.4 N. These values were in the range of normal tension in the mitral valve apparatus, and equivalent to only 19-24% of the total papillary muscle forces. Therefore, this technique does not appear to induce a non-physiologically high cyclic load on the mitral valve complex.

Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.

2011-11-01

Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely throughmore » previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.« less

Analysis Of 2H-Evaporator Scale Pot Bottom Sample [HTF-13-11-28H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.

2013-07-15

Savannah River Remediation (SRR) is planning to remove a buildup of sodium aluminosilicate scale from the 2H-evaporator pot by loading and soaking the pot with heated 1.5 M nitric acid solution. Sampling and analysis of the scale material from the 2H evaporator has been performed so that the evaporator can be chemically cleaned beginning July of 2013. Historically, since the operation of the Defense Waste Processing Facility (DWPF), silicon in the DWPF recycle stream combines with aluminum in the typical tank farm supernate to form sodium aluminosilicate scale mineral deposits in the 2H-evaporator pot and gravity drain line. The 2H-evaporatormore » scale samples analyzed by Savannah River National Laboratory (SRNL) came from the bottom cone sections of the 2H-evaporator pot. The sample holder from the 2H-evaporator wall was virtually empty and was not included in the analysis. It is worth noting that after the delivery of these 2H-evaporator scale samples to SRNL for the analyses, the plant customer determined that the 2H evaporator could be operated for additional period prior to requiring cleaning. Therefore, there was no need for expedited sample analysis as was presented in the Technical Task Request. However, a second set of 2H evaporator scale samples were expected in May of 2013, which would need expedited sample analysis. X-ray diffraction analysis (XRD) confirmed the bottom cone section sample from the 2H-evaporator pot consisted of nitrated cancrinite, (a crystalline sodium aluminosilicate solid), clarkeite and uranium oxide. There were also mercury compound XRD peaks which could not be matched and further X-ray fluorescence (XRF) analysis of the sample confirmed the existence of elemental mercury or mercuric oxide. On ''as received'' basis, the scale contained an average of 7.09E+00 wt % total uranium (n = 3; st.dev. = 8.31E-01 wt %) with a U-235 enrichment of 5.80E-01 % (n = 3; st.dev. = 3.96E-02 %). The measured U-238 concentration was 7.05E+00 wt % (n=3, st. dev. = 8.25E-01 wt %). Analyses results for Pu-238 and Pu-239, and Pu-241 are 7.06E-05 {+-} 7.63E-06 wt %, 9.45E-04 {+-} 3.52E-05 wt %, and <2.24E-06 wt %, respectively. These results are provided so that SRR can calculate the equivalent uranium-235 concentrations for the NCSA. Because this 2H evaporator pot bottom scale sample contained a significant amount of elemental mercury (11.7 wt % average), it is recommended that analysis for mercury be included in future Technical Task Requests on 2H evaporator sample analysis at SRNL. Results confirm that the uranium contained in the scale remains depleted with respect to natural uranium. SRNL did not calculate an equivalent U-235 enrichment, which takes into account other fissionable isotopes U-233, Pu-239 and Pu-241.« less

Geospatial Distribution of Heavy Metals in an Urban Soil, El Paso, Texas, USA

NASA Astrophysics Data System (ADS)

Amaya, M. A.; Elkekli, A. R.; Clague, J. W.; Grimida, S. E.; Pingitore, N. E., Jr.

2014-12-01

Some 500 city blocks were selected randomly via population-based stratification. Equal volumes of soil collected from the public space (where present) in front of each house on a block yielded a composite sample. Composites provide neighborhood level "smoothing" relative to sampling many individual houses, and greatly decrease laboratory effort/cost. In the laboratory 10 g of soil were comminuted in a ceramic ball mill, mixed with cellulose/ paraffin binder, and pressed (20 tons) into a pellet. A Panalytical Epsilon5 EDS-XRF, using 8 sequential secondary target conditions and 12 NIST and USGS multi-element rock standards provided analyses. The concentration of Pb ranged from 11 to 420 ppm; Cr, 4.3 - 52 ppm; Cu, 6.5 - 390 ppm; Zn, 17 - 480 ppm; Cd, 0.4 - 12 ppm; and Sb, 2.9 - 20 ppm. High levels of all metals characterize the urban core area of El Paso, which dates to the late 19th Century. This area hosts both commercial and old residential structures, as well as major highways and a large railroad yard. There currently is, and was in the past, considerable light industry in the area. Two highly traveled highway and one railroad border crossing over the Rio Grande into contiguous Cd. Juarez (population close to 2 million) add to current and past contamination. A century-old Pb-Cu-Zn smelter, recently demolished, forms the western boundary of the urban core. Heavy metal pollution from the smelter is recognized near the former site. Its effect on the rest of the urban core is uncertain due to the current and former presence of other heavy metal sources. Aggressive post-World War II growth and expansion of El Paso into the surrounding desert, as is common in the US Southwest, placed newer housing onto more pristine land surfaces. This is reflected in generally low-to-background levels of heavy metals in these newer areas of the city. Thus there is a strong contamination and heavy metals exposure risk gradient between older and newer neighborhoods within a single city, El Paso. In contrast, in older cities (e.g., US Northeast) where metropolitan boundaries are long-established, the equivalent risk gradient would be between the city and surrounding suburbs, each subject to separate government (political) controls and different funding and resources for cleanup and prevention measures. Research supported by NIEHS Grant 1RO1-ES11367.

Calcification persists with CO2-induced ocean acidification but decreases with warming for the Caribbean coral Siderastrea siderea

NASA Astrophysics Data System (ADS)

Castillo, K. D.; Ries, J. B.; Westfield, I. T.; Weiss, J. M.; Bruno, J. F.

2012-12-01

Atmospheric carbon dioxide (pCO2) induced ocean acidification and rising seawater temperatures are identified as two of the greatest threats to modern coral reefs. Within this century, surface seawater pH is expected to decrease by at least 0.3 units, and sea surface temperature is predicted to rise by 1 to 3 °C. However, uncertainty remains as to whether ocean acidification or ocean warming will have a more deleterious impact on coral reefs by the end of the century. Here, we present results of 95-day laboratory experiments in which we investigated the impact of CO2-induced ocean acidification and temperature on the calcification rate of the tropical reef-building zooxanthellate scleractinian coral Siderastrea siderea. We found that calcification rates for S. siderea, estimated from buoyant weighing, increased as pCO2 increased from a pre-industrial value of 324 ppm to a near-present-day value of 477 ppm, remained unchanged as pCO2 increased from 477 ppm to the predicted end-of-century value of 604 ppm, and only declined at 6-times the modern pCO2 value of 2553 ppm. Corals reared at average pCO2 of 488 ppm and at temperatures of 25 and 32 °C, approximately the lower and upper temperature extremes for this species, calcified at lower rates relative to corals reared at 28 °C under equivalent pCO2. These results support the existing evidence that scleractinian corals such as S. siderea are able to manipulate the carbonate chemistry at their calcification site, enabling them to maintain their calcification rates under elevated pCO2 levels predicted for the end of this century. However, exposure of S. siderea corals to sea surface temperatures predicted for tropical waters for the end of this century grossly impaired their rate of calcification. These findings suggest that ocean warming poses a more immediate threat to the coral S. siderea than does ocean acidification, at least under scenarios (B1, A1T, and B2) predicted by the Intergovernmental Panel on Climate Change for the end of the 21st century. We are presently investigating the calcification responses of S. siderea to the combined effects of ocean acidification and warming, in order to better constrain how corals will respond to global CO2-induced changes that are predicted for the near future.

Characterization of cores from an in-situ recovery mined uranium deposit in Wyoming: Implications for post-mining restoration

DOE Office of Scientific and Technical Information (OSTI.GOV)

WoldeGabriel, G.; Boukhalfa, H.; Ware, S. D.

In-situ recovery (ISR) of uranium (U) from sandstone-type roll-front deposits is a technology that involves the injection of solutions that consist of ground water fortified with oxygen and carbonate to promote the oxidative dissolution of U, which is pumped to recovery facilities located at the surface that capture the dissolved U and recycle the treated water. The ISR process alters the geochemical conditions in the subsurface creating conditions that are more favorable to the migration of uranium and other metals associated with the uranium deposit. There is a lack of clear understanding of the impact of ISR mining on themore » aquifer and host rocks of the post-mined site and the fate of residual U and other metals within the mined ore zone. We performed detailed petrographic, mineralogical, and geochemical analyses of several samples taken from about 7 m of core of the formerly the ISR-mined Smith Ranch–Highland uranium deposit in Wyoming. We show that previously mined cores contain significant residual uranium (U) present as coatings on pyrite and carbonaceous fragments. Coffinite was identified in three samples. Core samples with higher organic (> 1 wt.%) and clay (> 6–17 wt.%) contents yielded higher 234U/ 238U activity ratios (1.0–1.48) than those with lower organic and clay fractions. The ISR mining was inefficient in mobilizing U from the carbonaceous materials, which retained considerable U concentrations (374–11,534 ppm). This is in contrast with the deeper part of the ore zone, which was highly depleted in U and had very low 234U/ 238U activity ratios. This probably is due to greater contact with the lixiviant (leaching solution) during ISR mining. EXAFS analyses performed on grains with the highest U and Fe concentrations reveal that Fe is present in a reduced form as pyrite and U occurs mostly as U(IV) complexed by organic matter or as U(IV) phases of carbonate complexes. Moreover, U–O distances of ~ 2.05 Å were noted, indicating the potential formation of other poorly defined U(IV/VI) species. We also noted a small contribution from Udouble bond; length as m-dashO at 1.79 Å, which indicates that U is partially oxidized. There is no apparent U–S or U–Fe interaction in any of the U spectra analyzed. However, SEM analysis of thin sections prepared from the same core material reveals surficial U associated with pyrite which is probably a minor fraction of the total U present as thin coatings on the surface of pyrite. Our data show the presence of different structurally variable uranium forms associated with the mined cores. U associated with carbonaceous materials is probably from the original U mobilization that accumulated in the organic matter-rich areas under reducing conditions during shallow burial diagenesis. U associated with pyrite represents a small fraction of the total U and was likely deposited as a result of chemical reduction by pyrite. Our data suggest that areas rich in carbonaceous materials had limited exposure to the lixiviant solution, continue to be reducing, and still hold significant U resources. Because of their limited access to fluid flow, these areas might not contribute significantly to post-mining U release or attenuation. Areas with pyrite that are accessible to fluids seem to be more reactive and could act as reductants and facilitate U reduction and accumulation, limiting its migration.« less

Characterization of cores from an in-situ recovery mined uranium deposit in Wyoming: Implications for post-mining restoration

DOE PAGES

WoldeGabriel, G.; Boukhalfa, H.; Ware, S. D.; ...

2014-10-08

In-situ recovery (ISR) of uranium (U) from sandstone-type roll-front deposits is a technology that involves the injection of solutions that consist of ground water fortified with oxygen and carbonate to promote the oxidative dissolution of U, which is pumped to recovery facilities located at the surface that capture the dissolved U and recycle the treated water. The ISR process alters the geochemical conditions in the subsurface creating conditions that are more favorable to the migration of uranium and other metals associated with the uranium deposit. There is a lack of clear understanding of the impact of ISR mining on themore » aquifer and host rocks of the post-mined site and the fate of residual U and other metals within the mined ore zone. We performed detailed petrographic, mineralogical, and geochemical analyses of several samples taken from about 7 m of core of the formerly the ISR-mined Smith Ranch–Highland uranium deposit in Wyoming. We show that previously mined cores contain significant residual uranium (U) present as coatings on pyrite and carbonaceous fragments. Coffinite was identified in three samples. Core samples with higher organic (> 1 wt.%) and clay (> 6–17 wt.%) contents yielded higher 234U/ 238U activity ratios (1.0–1.48) than those with lower organic and clay fractions. The ISR mining was inefficient in mobilizing U from the carbonaceous materials, which retained considerable U concentrations (374–11,534 ppm). This is in contrast with the deeper part of the ore zone, which was highly depleted in U and had very low 234U/ 238U activity ratios. This probably is due to greater contact with the lixiviant (leaching solution) during ISR mining. EXAFS analyses performed on grains with the highest U and Fe concentrations reveal that Fe is present in a reduced form as pyrite and U occurs mostly as U(IV) complexed by organic matter or as U(IV) phases of carbonate complexes. Moreover, U–O distances of ~ 2.05 Å were noted, indicating the potential formation of other poorly defined U(IV/VI) species. We also noted a small contribution from Udouble bond; length as m-dashO at 1.79 Å, which indicates that U is partially oxidized. There is no apparent U–S or U–Fe interaction in any of the U spectra analyzed. However, SEM analysis of thin sections prepared from the same core material reveals surficial U associated with pyrite which is probably a minor fraction of the total U present as thin coatings on the surface of pyrite. Our data show the presence of different structurally variable uranium forms associated with the mined cores. U associated with carbonaceous materials is probably from the original U mobilization that accumulated in the organic matter-rich areas under reducing conditions during shallow burial diagenesis. U associated with pyrite represents a small fraction of the total U and was likely deposited as a result of chemical reduction by pyrite. Our data suggest that areas rich in carbonaceous materials had limited exposure to the lixiviant solution, continue to be reducing, and still hold significant U resources. Because of their limited access to fluid flow, these areas might not contribute significantly to post-mining U release or attenuation. Areas with pyrite that are accessible to fluids seem to be more reactive and could act as reductants and facilitate U reduction and accumulation, limiting its migration.« less

Impact of uranium (U) on the cellular glutathione pool and resultant consequences for the redox status of U.

PubMed

Viehweger, Katrin; Geipel, Gerhard; Bernhard, Gert

2011-12-01

Uranium (U) as a redox-active heavy metal can cause various redox imbalances in plant cells. Measurements of the cellular glutathione/glutathione disulfide (GSH/GSSG) by HPLC after cellular U contact revealed an interference with this essential redox couple. The GSH content remained unaffected by 10 μM U whereas the GSSG level immediately increased. In contrast, higher U concentrations (50 μM) drastically raised both forms. Using the Nernst equation, it was possible to calculate the half-cell reduction potential of 2GSH/GSSG. In case of lower U contents the cellular redox environment shifted towards more oxidizing conditions whereas the opposite effect was obtained by higher U contents. This indicates that U contact causes a consumption of reduced redox equivalents. Artificial depletion of GSH by chlorodinitrobenzene and measuring the cellular reducing capacity by tetrazolium salt reduction underlined the strong requirement of reduced redox equivalents. An additional element of cellular U detoxification mechanisms is the complex formation between the heavy metal and carboxylic functionalities of GSH. Because two GSH molecules catalyze electron transfers each with one electron forming a dimer (GSSG) two UO(2) (2+) are reduced to each UO(2) (+) by unbound redox sensitive sulfhydryl moieties. UO(2) (+) subsequently disproportionates to UO(2) (2+) and U(4+). This explains that in vitro experiments revealed a reduction to U(IV) of only around 33% of initial U(VI). Cellular U(IV) was transiently detected with the highest level after 2 h of U contact. Hence, it can be proposed that these reducing processes are an important element of defense reactions induced by this heavy metal.

The study of equivalent dose of uranium in long bean (V. U. Sesquipedalis) and the effect on human

NASA Astrophysics Data System (ADS)

Rashid, Nur Shahidah Abdul; Yoshandi, Tengku Mohammad; Majid, Sukiman Sarmania Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok

2016-01-01

In the case of accidental release of Uranium-238 (238U) radionuclides in a nuclear facility or in the environment, internal contamination by either acute or chronic exposure has the potential to induce both radiological and chemical toxic effects. A study was conducted to estimate the 238U radionuclide concentration in the long beans using Induced Coupled Mass Plasma-Spectrometry (ICP-MS). 238U radionuclide is a naturally occurring radioactive material that can be found in soil and can be transferred to the long bean (Vigna unguiculata subsp. Sesquapedalis) directly or indirectly via water or air. Kidney and liver are the major sites of deposition of 238U radionuclide. The obtained dose exposed in the liver and kidney is used to assess the safety level for public intake of 238U radionuclide from the consumption of long beans. The concentration of 238U radionuclide measured in long bean samples was 0.0226 ± 0.0009 mg/kg. Total activity of 238U radionuclide was 0.0044 ± 0.0002 Bq/day with the daily intake of 0.3545 ± 0.0143 µg/day and the annual committed effective dose due to ingestion of 238U radionuclide in long beans was 0.2230 ± 0.0087 µSv/year. The committed equivalent dose of 238U radionuclide from the assessment in the liver and kidney are 0.4198 ± 0.0165 nSv and 10.9335 ± 0.4288 nSv. The risk of cancer of 238U radionuclide was determined to be (86.0466 ± 3.3748) × 10-9. Thus, the results concluded that 238U radionuclide in local long beans was in the permitted level and safe to consume without posing any significant radiological threat to population.

Emissions of nitrogen oxides from an experimental hydrogen-fueled gas turbine combustor

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Ingebo, R. D.

1974-01-01

The effect of operating variables of a hydrogen fueled combustor on exhaust concentrations of total oxides of nitrogen was determined at inlet-air temperature levels up to 810 K, pressure of 414,000N/sa m, and reference velocity of 21.3 m/sec. The combustor, which was originally designed for hydrocarbon fuel produced a NO(x) concentration of 380 ppm with hydrogen at 810 K inlet-air temperature. A reduction in NO(x) of about 30 % was obtained by modification to a lean or rich primary zone. The lowest NO(x) levels obtained with hydrogen were equivalent to those of the reference combustor burning hydrocarbon fuels.

Crystal chemistry of pyrochlore from the Mesozoic Panda Hill carbonatite deposit, western Tanzania

NASA Astrophysics Data System (ADS)

Boniface, Nelson

2017-02-01

The Mesozoic Panda Hill carbonatite deposit in western Tanzania hosts pyrochlore, an ore and source of niobium. This study was conducted to establish the contents of radioactive elements (uranium and thorium) in pyrochlore along with the concentration of niobium in the ore. The pyrochlore is mainly hosted in sövite and is structurally controlled by NW-SE (SW dipping) or NE-SW (NW dipping) magmatic flow bands with dip angles of between 60° and 90°. Higher concentrations of pyrochlore are associated with magnetite, apatite and/or phlogopite rich flow bands. Electron microprobe analyses on single crystals of pyrochlore yield very low UO2 concentrations that range between 0 and 0.09 wt% (equivalent to 0 atoms per formula unit: a.p.f.u.) and ThO2 between 0.55 and 1.05 wt% (equivalent to 0.1 a.p.f.u.). The analyses reveal high concentrations of Nb2O5 (ranging between 57.13 and 65.50 wt%, equivalent to a.p.f.u. ranging between 1.33 and 1.43) and therefore the Panda Hill Nb-oxide is classified as pyrochlore sensu stricto. These data point to a non radioactive pyrochlore and a deposit rich in Nb at Panda Hill. The Panda Hill pyrochlore has low concentrations of REEs as displayed by La2O3 that range between 0.10 and 0.49 wt% (equivalent to a.p.f.u. ranging between 0 and 0.01) and Ce2O3 ranging between 0.86 and 1.80 wt% (equivalent to a.p.f.u. ranging between 0.02 and 0.03), Pr2O3 concentrations range between 0 and 0.23 wt% (equivalent to 0 a.p.f.u.), and Y2O3 is 0 wt% (equivalent to 0 a.p.f.u.). The abundance of the REEs in pyroclore at the Panda Hill Carbonatite deposit is of no economic significance.

A sensitive and rapid assay for 4-aminophenol in paracetamol drug and tablet formulation, by flow injection analysis with spectrophotometric detection.

PubMed

Bloomfield, M S

2002-12-06

4-Aminophenol (4AP) is the primary degradation product of paracetamol which is limited at a low level (50 ppm or 0.005% w/w) in the drug substance by the European, United States, British and German Pharmacopoeias, employing a manual colourimetric limit test. The 4AP limit is widened to 1000 ppm or 0.1% w/w for the tablet product monographs, which quote the use of a less sensitive automated HPLC method. The lower drug substance specification limit is applied to our products, (50 ppm, equivalent to 25 mug 4AP in a tablet containing 500-mg paracetamol) and the pharmacopoeial HPLC assay was not suitable at this low level due to matrix interference. For routine analysis a rapid, automated assay was required. This paper presents a highly sensitive, precise and automated method employing the technique of Flow Injection (FI) analysis to quantitatively assay low levels of this degradant. A solution of the drug substance, or an extract of the tablets, containing 4AP and paracetamol is injected into a solvent carrier stream and merged on-line with alkaline sodium nitroprusside reagent, to form a specific blue derivative which is detected spectrophotometrically at 710 nm. Standard HPLC equipment is used throughout. The procedure is fully quantitative and has been optimised for sensitivity and robustness using a multivariate experimental design (multi-level 'Central Composite' response surface) model. The method has been fully validated and is linear down to 0.01 mug ml(-1). The approach should be applicable to a range of paracetamol products.

Influence of root exudation of white lupine (Lupinus albus L.) on uranium phytoavailability in a naturally uranium-rich soil.

PubMed

Henner, Pascale; Brédoire, Félix; Tailliez, Antoine; Coppin, Frédéric; Pierrisnard, Sylvie; Camilleri, Virginie; Keller, Catherine

2018-10-01

Mechanisms of uranium (U) transfer from soil to plants remain poorly understood. The kinetics of supply of U to the soil solution from solid phases could be a key point to understand its phytoavailability and implications for environmental risk assessment. Root activity, particularly the continuous release of organic acids in the rhizosphere, could have an effect on this supply. We tested the impact of citrate exudation by roots of Lupinus albus, either P-sufficient (P+) or P-deficient (P-), on the phytoavailability of U from a naturally contaminated soil (total content of 413 mg U kg -1 ) using a rhizotest design. Combined effects of P (P-/P+ used to modulate plant physiology) and citrate (model exudate) on the solubilization of U contained in the soils were tested in closed reactors (batch). The batch experiment showed the existence of a low U available pool (0.4% total U) and high accessibility (k d ' around 20 L kg -1 ) which was not significantly affected by P treatment or citrate concentrations. Analysis of U, Fe, Ca, P and citrate concentrations in the batches suggested a complex combination of mechanisms and factors including desorption, resorption, precipitation, co-sorption. On rhizotest, L. albus plants extracted 0.5-0.75% of the total U and between 25 and 40% of the estimated available U present in the rhizotest in 5 days. Uranium accumulation at the whole plant level (20 mg U kg -1 d.w. , shoot to root ratio around 10 -3 ) seemed to be dependent neither on the plant P nutrition status nor citrate exudation level, possibly in relation with the equivalent accessibility of U whatever the growth conditions. Yet differential translocation to shoots seemed to be positively correlated to citrate exudation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Radioactive rare-earth deposit at Scrub Oaks mine, Morris County, New Jersey

USGS Publications Warehouse

Klemic, Harry; Heyl, A.V.; Taylor, Audrey R.; Stone, Jerome

1959-01-01

A deposit of rare-earth minerals in the Scrub Oaks iron mine, Morris County, N. J., was mapped and sampled in 1955. The rare-earth minerals are mainly in coarse-grained magnetite ore and in pegmatite adjacent to it. Discrete bodies of rare-earth-bearing magnetite ore apparently follow the plunge of the main magnetite ore body at the north end of the mine. Radioactivity of the ore containing rare earths is about 0.2 to 0.6 mllliroentgens per hour. The principal minerals of the deposit are quartz, magnetite, hematite, albiteoligoclase, perthite and antiperthite. Xenotime and doverite aggregates and bastnaesite with intermixed leucoxene are the most abundant rare-earth minerals, and zircon, sphene, chevkinite, apatite, and monazite are of minor abundance in the ore. The rare-earth elements are partly differentiated into cerium-rich bastnaesite, chevkinite, and monazite, and yttrium-rich xenotime and doverite. Apatite, zircon, and sphene contain both cerium and yttrium group earths. Eleven samples of radioactive ore and rock average 0.009 percent uranium, 0.062 percent thorium, 1.51 percent combined rare-earth oxides including yttrium oxide and 24.8 percent iron. Scatter diagrams of sample data show a direct correlation between equivalent uranium, uranium, thorium, and combined rare^ earth oxides. Both cerium- and yttrium-group earths are abundant in the rare-earth minerals. Radioactive magnetite ore containing rare-earth minerals probably formed as a variant of the magnetite mineralization that produced the main iron ore of the Scrub Oaks deposit. The rare-earth minerals and the iron ore were deposited contemporaneously. Zircon crystals, probably deposited at the same time, have been determined by the Larsen method to be about 550 to 600 million years old (late Precambrian age). Uranium, thorium, and rare-earth elements are potential byproducts of iron in the coarse-grained magnetite ore.

Industrial safety and applied health physics. Annual report for 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-11-01

Information is reported in sections entitled: radiation monitoring; Environmental Management Program; radiation and safety surveys; industrial safety and special projects; Office of Operational Safety; and training, lectures, publications, and professional activities. There were no external or internal exposures to personnel which exceeded the standards for radiation protection as defined in DOE Manual Chapter 0524. Only 35 employees received whole body dose equivalents of 10 mSv (1 rem) or greater. There were no releases of gaseous waste from the Laboratory which were of a level that required an incident report to DOE. There were no releases of liquid radioactive waste frommore » the Laboratory which were of a level that required an incident report to DOE. The quantity of those radionuclides of primary concern in the Clinch River, based on the concentration measured at White Oak Dam and the dilution afforded by the Clinch River, averaged 0.16 percent of the concentration guide. The average background level at the Perimeter Air Monitoring (PAM) stations during 1980 was 9.0 ..mu..rad/h (0.090 ..mu..Gy/h). Soil samples were collected at all perimeter and remote monitoring stations and analyzed for eleven radionuclides including plutonium and uranium. Plutonium-239 content ranged from 0.37 Bq/kg (0.01 pCi/g) to 1.5 Bq/kg (0.04 pCi/g), and the uranium-235 content ranged from 0.7 Bq/kg (0.02 pCi/g) to 16 Bq/kg (0.43 pCi/g). Grass samples were collected at all perimeter and remote monitoring stations and analyzed for twelve radionuclides including plutonium and uranium. Plutonium-239 content ranged from 0.04 Bq/kg (0.001 pCi/g) to 0.07 Bq/kg (0.002 pCi/g), and the uranium-235 content ranged from 0.37 Bq/kg (0.01 pCi/g) to 12 Bq/kg (0.33 pCi/g).« less

Effect of lyophilized water extracts of Melissa officinalis on the stability of algae and linseed oil-in-water emulsion to be used as a functional ingredient in meat products.

PubMed

de Ciriano, Mikel García-Iñiguez; Rehecho, Sheyla; Calvo, Maria Isabel; Cavero, Rita Yolanda; Navarro, Iñigo; Astiasarán, Iciar; Ansorena, Diana

2010-06-01

Previous work pointed out the possibility to enhance the nutritional value of meat products using long chain omega-3 PUFA enriched emulsions. Oil-in-water emulsions elaborated with a mixture of algae and linseed oils (15:10) in order to be used as functional ingredient were stabilized with BHA (butylhydroxyanisol) or with a lyophilized water extract of Melissa officinalis L. (Lemon balm). The lipid profile of the oil mixture showed a high amount of DHA (31.7%), oleic (25.4%) and alpha-linolenic acid (12.7%) resulting in a very low omega-6/omega-3 ratio (0.12). The lyophilized extract of M. officinalis showed a high antioxidant activity (being 62ppm of the lyophilized water extract of Melissa equivalent to 200ppm of BHA, using the DPPH assay as reference), and high total phenolic content. Studying the oxidation process in the emulsions during 15days at room temperature, it could be concluded that this extract was as efficient as BHA in order to control the thiobarbituric acid reactive substances (TBARS) formation. Copyright 2010 Elsevier Ltd. All rights reserved.

Evidence for indigenous nitrogen in sedimentary and aeolian deposits from the Curiosity rover investigations at Gale crater, Mars

PubMed Central

Stern, Jennifer C.; Sutter, Brad; Freissinet, Caroline; Navarro-González, Rafael; McKay, Christopher P.; Archer, P. Douglas; Buch, Arnaud; Brunner, Anna E.; Coll, Patrice; Eigenbrode, Jennifer L.; Fairen, Alberto G.; Franz, Heather B.; Glavin, Daniel P.; Kashyap, Srishti; McAdam, Amy C.; Ming, Douglas W.; Steele, Andrew; Szopa, Cyril; Wray, James J.; Martín-Torres, F. Javier; Zorzano, Maria-Paz; Conrad, Pamela G.; Mahaffy, Paul R.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Bell, James F.; Edgar, Lauren; Farmer, Jack; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Grotzinger, John; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stack, Katie; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sánchez, Pablo Sobrón; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Armiens-Aparicio, Carlos; Rodríguez, Javier Caride; Blázquez, Isaías Carrasco; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Hettrich, Sebastian; Malvitte, Alain Lepinette; Jiménez, Mercedes Marín; Martínez-Frías, Jesús; Martín-Soler, Javier; - Torres, F. Javier Martín; Jurado, Antonio Molina; Mora-Sotomayor, Luis; Caro, Guillermo Muñoz; López, Sara Navarro; Peinado-González, Verónica; Pla-García, Jorge; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio José; Fuentes, Sara Alejandra Sans; Martinez, Eduardo Sebastian; Redondo, Josefina Torres; Urqui-O'Callaghan, Roser; Mier, María-Paz Zorzano; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Sullivan, Robert; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Kemppinen, Osku; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Gupta, Sanjeev; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; d’Uston, Claude; Forni, Olivier; Gasnault, Olivier; Lasue, Jérémie; Lee, Qiu-Mei; Maurice, Sylvestre; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Israël, Guy; Szopa, Cyril; Dromart, Gilles; Robert, François; Sautter, Violaine; Le Mouélic, Stéphane; Mangold, Nicolas; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Wiens, Roger C.; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Edgett, Kenneth; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; Malin, Michael; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Van Beek, Tessa; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Goetz, Walter; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Wilhelm, Mary Beth; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Jones, Andrea; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Blaney, Diana; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Ehlmann, Bethany; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; Juarez, Manuel de la Torre; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Williams, Rebecca M. E.; Yingst, Aileen; Lewis, Kevin; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Schwenzer, Susanne P.; Anderson, Ryan B.; Herkenhoff, Kenneth; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Ávalos, Juan José Blanco; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; Navarro-González, Rafael; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Dietrich, William; Kortmann, Onno; Palucis, Marisa; Sumner, Dawn Y.; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Rubin, David; Jakosky, Bruce; Balic-Zunic, Tonci; Frydenvang, Jens; Jensen, Jaqueline Kløvgaard; Kinch, Kjartan; Koefoed, Asmus; Madsen, Morten Bo; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Atlaskin, Evgeny; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mueller-Mellin, Reinhold; Wimmer-Schweingruber, Robert; Bridges, John C.; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Newsom, Horton; Ollila, Ann; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Kah, Linda C.; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Kuzmin, Ruslan; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

2015-01-01

The Sample Analysis at Mars (SAM) investigation on the Mars Science Laboratory (MSL) Curiosity rover has detected oxidized nitrogen-bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within Gale crater. Total N concentrations ranged from 20 to 250 nmol N per sample. After subtraction of known N sources in SAM, our results support the equivalent of 110–300 ppm of nitrate in the Rocknest (RN) aeolian samples, and 70–260 and 330–1,100 ppm nitrate in John Klein (JK) and Cumberland (CB) mudstone deposits, respectively. Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and, specifically, for the potential evolution of a nitrogen cycle at some point in martian history. The detection of nitrate in both wind-drifted fines (RN) and in mudstone (JK, CB) is likely a result of N2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient Mars. Fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient Mars, potentially providing a biochemically accessible source of nitrogen. PMID:25831544

Evidence for indigenous nitrogen in sedimentary and aeolian deposits from the Curiosity rover investigations at Gale crater, Mars.

PubMed

Stern, Jennifer C; Sutter, Brad; Freissinet, Caroline; Navarro-González, Rafael; McKay, Christopher P; Archer, P Douglas; Buch, Arnaud; Brunner, Anna E; Coll, Patrice; Eigenbrode, Jennifer L; Fairen, Alberto G; Franz, Heather B; Glavin, Daniel P; Kashyap, Srishti; McAdam, Amy C; Ming, Douglas W; Steele, Andrew; Szopa, Cyril; Wray, James J; Martín-Torres, F Javier; Zorzano, Maria-Paz; Conrad, Pamela G; Mahaffy, Paul R

2015-04-07

The Sample Analysis at Mars (SAM) investigation on the Mars Science Laboratory (MSL) Curiosity rover has detected oxidized nitrogen-bearing compounds during pyrolysis of scooped aeolian sediments and drilled sedimentary deposits within Gale crater. Total N concentrations ranged from 20 to 250 nmol N per sample. After subtraction of known N sources in SAM, our results support the equivalent of 110-300 ppm of nitrate in the Rocknest (RN) aeolian samples, and 70-260 and 330-1,100 ppm nitrate in John Klein (JK) and Cumberland (CB) mudstone deposits, respectively. Discovery of indigenous martian nitrogen in Mars surface materials has important implications for habitability and, specifically, for the potential evolution of a nitrogen cycle at some point in martian history. The detection of nitrate in both wind-drifted fines (RN) and in mudstone (JK, CB) is likely a result of N2 fixation to nitrate generated by thermal shock from impact or volcanic plume lightning on ancient Mars. Fixed nitrogen could have facilitated the development of a primitive nitrogen cycle on the surface of ancient Mars, potentially providing a biochemically accessible source of nitrogen.

Paleobotany and Global Change: Important Lessons for Species to Biomes from Vegetation Responses to Past Global Change.

PubMed

McElwain, Jennifer C

2018-04-29

Human carbon use during the next century will lead to atmospheric carbon dioxide concentrations (pCO 2 ) that have been unprecedented for the past 50-100+ million years according to fossil plant-based CO 2 estimates. The paleobotanical record of plants offers key insights into vegetation responses to past global change, including suitable analogs for Earth's climatic future. Past global warming events have resulted in transient poleward migration at rates that are equivalent to the lowest climate velocities required for current taxa to keep pace with climate change. Paleobiome reconstructions suggest that the current tundra biome is the biome most threatened by global warming. The common occurrence of paleoforests at high polar latitudes when pCO 2 was above 500 ppm suggests that the advance of woody shrub and tree taxa into tundra environments may be inevitable. Fossil pollen studies demonstrate the resilience of wet tropical forests to global change up to 700 ppm CO 2 , contrary to modeled predictions of the future. The paleobotanical record also demonstrates a high capacity for functional trait evolution as an additional strategy to migration and maintenance of a species' climate envelope in response to global change.

Determination of premining geochemical background and delineation of extent of sediment contamination in Blue Creek downstream from Midnite Mine, Stevens County, Washington

USGS Publications Warehouse

Church, Stan E.; Kirschner, Frederick E.; Choate, LaDonna M.; Lamothe, Paul J.; Budahn, James R.; Brown, Zoe Ann

2008-01-01

Geochemical and radionuclide studies of sediment recovered from eight core sites in the Blue Creek flood plain and Blue Creek delta downstream in Lake Roosevelt provided a stratigraphic geochemical record of the contamination from uranium mining at the Midnite Mine. Sediment recovered from cores in a wetland immediately downstream from the mine site as well as from sediment catchments in Blue Creek and from cores in the delta in Blue Creek cove provided sufficient data to determine the premining geochemical background for the Midnite Mine tributary drainage. These data provide a geochemical background that includes material eroded from the Midnite Mine site prior to mine development. Premining geochemical background for the Blue Creek basin has also been determined using stream-sediment samples from parts of the Blue Creek, Oyachen Creek, and Sand Creek drainage basins not immediately impacted by mining. Sediment geochemistry showed that premining uranium concentrations in the Midnite Mine tributary immediately downstream of the mine site were strongly elevated relative to the crustal abundance of uranium (2.3 ppm). Cesium-137 (137Cs) data and public records of production at the Midnite Mine site provided age control to document timelines in the sediment from the core immediately downstream from the mine site. Mining at the Midnite Mine site on the Spokane Indian Reservation between 1956 and 1981 resulted in production of more than 10 million pounds of U3O8. Contamination of the sediment by uranium during the mining period is documented from the Midnite Mine along a small tributary to the confluence of Blue Creek, in Blue Creek, and into the Blue Creek delta. During the period of active mining (1956?1981), enrichment of base metals in the sediment of Blue Creek delta was elevated by as much as 4 times the concentration of those same metals prior to mining. Cadmium concentrations were elevated by a factor of 10 and uranium by factors of 16 to 55 times premining geochemical background determined upstream of the mine site. Postmining metal concentrations in sediment are lower than during the mining period, but remain elevated relative to premining geochemical background. Furthermore, the sediment composition of surface sediment in the Blue Creek delta is contaminated. Base-metal contamination by arsenic, cadmium, lead, and zinc in sediment in the delta in Blue Creek cove is dominated by suspended sediment from the Coeur d?Alene mining district. Uranium contamination in surface sediment in the delta of Blue Creek cove extends at least 500 meters downstream from the mouth of Blue Creek as defined by the 1,290-ft elevation boundary between lands administered by the National Park Service and the Spokane Indian Tribe. Comparisons of the premining geochemical background to sediment sampled during the period the mine was in operation, and to the sediment data from the postmining period, are used to delineate the extent of contaminated sediment in Blue Creek cove along the thalweg of Blue Creek into Lake Roosevelt. The extent of contamination out into Lake Roosevelt by mining remains open.

Uranium-series dating of pedogenic silica and carbonate, Crater Flat, Nevada

NASA Astrophysics Data System (ADS)

Ludwig, K. R.; Paces, J. B.

2002-02-01

A 230Th-234U-238U dating study on pedogenic silica-carbonate clast rinds and matrix laminae from alluvium in Crater Flat, Nevada was conducted using small-sample thermal-ionization mass spectrometry (TIMS) analyses on a large suite of samples. Though the 232Th content of these soils is not particularly low (mostly 0.1-9 ppm), the high U content of the silica component (mostly 4-26 ppm) makes them particularly suitable for 230Th/U dating on single, 10 to 200 mg totally-digested samples using TIMS. We observed that (1) both micro- (within-rind) and macro-stratigraphic (mappable deposit) order of the 230Th/U ages were preserved in all cases; (2) back-calculated initial 234U/238U fall in a restricted range (typically 1.67±0.19), so that 234U/238U ages with errors of about 100 kyr (2σ) could be reliably determined for the oldest, 400 to 1000 ka rinds; and (3) though 13 of the samples were >350 ka, only three showed evidence for an open-system history, even though the sensitivity of such old samples to isotopic disruption is very high. An attempt to use leach-residue techniques to separate pedogenic from detrital U and Th failed, yielding corrupt 230Th/U ages. We conclude that 230Th/U ages determined from totally dissolved, multiple sub-mm size subsamples provide more reliable estimates of soil chronology than methods employing larger samples, chemical enhancement of 238U/232Th, or isochrons.

SUMMARY TECHNICAL REPORT ON FEED MATERIALS FOR THE PERIOD APRIL 1, 1959 TO JUNE 30, 1959

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, J.W. ed.

1959-07-20

Anaconda Acld, Kermac, Moab, Rifle, and Texas Zinc uranium concentrates were evaluated (the laboratory portlon of feed material evaluation). Laboratory equilibrium tests and Pilot Plant 2-inch-column extraction tests demonstrated effective distribution of uranium into a TBPkerosene solvent from aqueous phases containing as little as 0.5N HNO/sub 3/ and varying amounts of added metal nitrates (NaNO/sub 3/). The concentration of assoclated nitric acid in dilute aqueous nitric acld solutions was determined after values were obtained for the equillbrium constant for the reaction of tri-n-butyl phosphate with associated nitric acid and for the equilibrium distribution constant for the partition of associated nitricmore » acld into tri-n-butyl phosphate. Optimum partition of uranium into tri-n-butyl phosphate was realized in the laboratory by using an aqueous uranyl nitrate solution containing sufficient hydrogen ions to promote extraction and a low concentration of associated nitric acid. An Ohmart system for controlling the uranium profile in the A'' extractlon column was installed on Refinery pulse columns. Use of this system improved control but did not stop all column upsets. The effect of 13 to l89 ppm sodium contaminatlon upon hydrofluorination conversion of teraperature at the site of the reaction. Uranyl sulfate was shown to undergo an enantiotroplc transitlon at 755 deg C and to decompose to U/sub 3/O/sub 8/ in an atmosphere of oxygen sulfur dioxide, which gases are evolved during decoraposition. Decontamination of sodium, calcium, nickel, magnesium, gadolinium, and dysprosium was achieved in a laboratory investigatlon of the ADU process. UO/sub 2/ produced by reductions programmed from 700 to ll00 deg F was hydrofluorinated at programmed temperatures of 550 to 1100 deg F and isothermally at ll00 deg F. Good conversion was obtained for material whose source was ADU calcined at 1200 deg F. Uranium derbles were classified by the present method of derby grading and were then examined for slag coverage, slag volume, and slag weight. There was a high degree of overlap of these parameters for adjacent grades. A hydraulic separator for separatlng uranlum from magnesium and magnesium fluorlde was fabrlcated. Excellent separatlon was obtained for +l6 mesh material. A hydrochloric acid dissolution- UF/sub 4/ precipitation process for routing scrap materials to the reductlon-to- metal step was examined. The purification obtained was noted, and process conditions were varied to determine their effect upon UF/sub 4/ density, UF/sub 4/ purity and precipitation time. Three types of uranium scrap were subjected to the HCl dissolution-aqueous precipitation Winlo process to determine the purification achieved. Green salt made from dolomitlc bomb liner residues was found to be grossly contaminated. Acceptable green salt was raade from pickle liquor treated with formaldehyde and from pickle liquor plus black oxide. Nominal 80% yields were obtained in the recovery of magnesium metal by reaction of calcium carblde with magnesium fluoride slag and in the recovery of HF by the reactlon of sulfuric acid wlth magnesium fluoride slag. A sample holder for use in quantitative preferred orientation studies was fabricated. The holder, designed to fit a North American Philips Gonionweter, will accommodate specimens up to l 13/16 inches in diameter and incorporates a precision ball bearing. A satisfactory technique was developed for the analysis of uranium metal for traces of fluoride. A direct flame photometric method is glven for the determination of magnesium in uranium ore concentrates. No chemical separation step is required, except for high-iron-content ores. (auth)« less

Surface Modification of Silicon Pillar Arrays To Enhance Fluorescence Detection of Uranium and DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Danielle R.; Charlton, Jennifer J.; Hatab, Nahla A.

There is an ever-growing need for detection methods that are both sensitive and efficient, such that reagent and sample consumption is minimized. Nanopillar arrays offer an attractive option to fill this need by virtue of their small scale in conjunction with their field enhancement intensity gains. This work investigates the use of nanopillar substrates for the detection of the uranyl ion and DNA, two analytes unalike but for their low quantum efficiencies combined with the need for high-throughput analyses. Here in this paper, the adaptability of these platforms was explored, as methods for the successful surface immobilization of both analytesmore » were developed and compared, resulting in a limit of detection for the uranyl ion of less than 1 ppm with a 0.2 μL sample volume. Moreover, differentiation between single-stranded and double-stranded DNA was possible, including qualitative identification between double-stranded DNA and DNA of the same sequence, but with a 10-base-pair mismatch.« less

Surface Modification of Silicon Pillar Arrays To Enhance Fluorescence Detection of Uranium and DNA

DOE PAGES

Lincoln, Danielle R.; Charlton, Jennifer J.; Hatab, Nahla A.; ...

2017-10-27

There is an ever-growing need for detection methods that are both sensitive and efficient, such that reagent and sample consumption is minimized. Nanopillar arrays offer an attractive option to fill this need by virtue of their small scale in conjunction with their field enhancement intensity gains. This work investigates the use of nanopillar substrates for the detection of the uranyl ion and DNA, two analytes unalike but for their low quantum efficiencies combined with the need for high-throughput analyses. Here in this paper, the adaptability of these platforms was explored, as methods for the successful surface immobilization of both analytesmore » were developed and compared, resulting in a limit of detection for the uranyl ion of less than 1 ppm with a 0.2 μL sample volume. Moreover, differentiation between single-stranded and double-stranded DNA was possible, including qualitative identification between double-stranded DNA and DNA of the same sequence, but with a 10-base-pair mismatch.« less

Zeolite-clay mineral zonation of volcaniclastic sediments within the McDermitt caldera complex of Nevada and Oregon

USGS Publications Warehouse

Glanzman, Richard K.; Rytuba, James J.

1979-01-01

Volcaniclastic sediments deposited in the moat of the collapsed McDermitt caldera complex have been altered chiefly to zeolites and potassium feldspar. The original rhyolitic and peralkaline ash-flow tuffs are included in conglomerates at the caldera rims and grade into a lacustrine series near the center of the collapse. The tuffs show a lateral zeolitic alteration from almost fresh glass to clinoptilolite, clinoptilolite-mordenite, and erionite; to analcime-potassium feldspar; and finally to potassium feldspar. Vertical zonation is in approximately the same order. Clay minerals in associated mudstones, on the other hand, show little lateral variation but a distinct vertical zonation, having a basal dioctahedral smectite, a medial trioctahedral smectite, and an upper dioctahedral smectite. The medial trioctahedral smectite is enriched in lithium (as much as 6,800 ppm Li). Hydrothermal alteration of the volcaniclastic sediments, forming both mercury and uranium deposits, caused a distinct zeolite and clay-mineral zonation within the general lateral zonation. The center of alteration is generally potassium feldspar, commonly associated with alunite. Potassium feldspar grades laterally and vertically to either clinoptilolite or clinoptilolite-mordenite, generally associated with gypsum. This zone then grades vertically and laterally into fresh glass. The clay minerals are a dioctahedral smectite, a mixed-layer clay mineral, and a 7-A clay mineral. The mixed-layer and 7-A clay minerals are associated with the potassium feldspar-alunite zone of alteration, and the dioctahedral smectite is associated with clinoptilolite. This mineralogical zonation may be an exploration guide for mercury and uranium mineralization in the caldera complex environment.

Multielement chemical and statistical analyses from a uranium hydrogeochemical and stream-sediment survey in and near the Elkhorn Mountains, Jefferson County, Montana; Part II, Stream sediments

USGS Publications Warehouse

Suits, V.J.; Wenrich, K.J.

1982-01-01

Fifty-two stream-sediment samples, collected from an area south of Helena, Jefferson County, Montana, were sieved into two size fractions (50 ppm for the fine fraction) were encountered in samples from the Warm Springs Creek drainage area, along Prickly Pear Creek near Welmer and Golconda Creeks and along Muskrat Creek. All groups showed a significant correlation at the 99 percent confidence level (r between 0.73 and 0.77) between U and Th. Uranium was found to correlate significantly only with Th (as mentioned above) and with -Ni in the fine fraction of the volcanics group. U correlates significantly with -Al2O3, Ba, organic C, -K2O, -Sr and Y in both size fractions for the Boulder batholith. Correlations between U and each of several elements differ for the fine and coarse fractions of the Boulder batholith group, suggesting that the U distribution in these stream sediments is in large part controlled by grain size. Correlations were found between U and CaO, Cr, Fe203, -Na2O, Sc, -SiO2, TiO2, Yb and Zr in the coarse fraction but not in the fine fraction. U correlates weakly (to the 90% confidence level, crc<.37) with -Co and -Cu in the fine but not the coarse fraction. These results are compared to a previous study in the northern Absaroka mountains. Correlation coefficients between all other elements determined from these samples are also shown in Tables 12 to 15.

Tris(phosphinoamide)-supported uranium-cobalt heterobimetallic complexes featuring Co → U dative interactions.

PubMed

Napoline, J Wesley; Kraft, Steven J; Matson, Ellen M; Fanwick, Phillip E; Bart, Suzanne C; Thomas, Christine M

2013-10-21

A series of tris- and tetrakis(phosphinoamide) U/Co complexes has been synthesized. The uranium precursors, (η(2)-Ph2PN(i)Pr)4U (1), (η(2)-(i)Pr2PNMes)4U (2), (η(2)-Ph2PN(i)Pr)3UCl (3), and (η(2)-(i)Pr2PNMes)3UI (4), were easily accessed via addition of the appropriate stoichiometric equivalents of [Ph2PN(i)Pr]K or [(i)Pr2PNMes]K to UCl4 or UI4(dioxane)2. Although the phosphinoamide ligands in 1 and 4 have been shown to coordinate to U in an η(2)-fashion in the solid state, the phosphines are sufficiently labile in solution to coordinate cobalt upon addition of CoI2, generating the heterobimetallic Co/U complexes ICo(Ph2PN(i)Pr)3U[η(2)-Ph2PN(i)Pr] (5), ICo((i)Pr2PNMes)3U[η(2)-((i)Pr2PNMes)] (6), ICo(Ph2PN(i)Pr)3UI (7), and ICo((i)Pr2PNMes)3UI (8). Structural characterization of complexes 5 and 7 reveals reasonably short Co-U interatomic distances, with 7 exhibiting the shortest transition metal-uranium distance ever reported (2.874(3) Å). Complexes 7 and 8 were studied by cyclic voltammetry to examine the influence of the metal-metal interaction on the redox properties compared with both monometallic Co and heterobimetallic Co/Zr complexes. Theoretical studies are used to further elucidate the nature of the transition metal-actinide interaction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weydert, M.; Brennan, J.G.; Andersen, R.A.

Reaction of (MeC{sub 5}H{sub 4}){sub 3}UX (X = Cl, MeC{sub 5}H{sub 4}) with t-BuLi affords the tertiary alkyl complex (MeC{sub 5}H{sub 4}){sub 3}U(t-Bu). Despite uranium(IV) generally being the preferred oxidation state in organometallic systems, (MeC{sub 5}H{sub 4}){sub 3}U(t-Bu) reacts with Lewis bases (L = PMe{sub 3}, THF, RCN, RNC) to yield the reduced uranium(III) base adducts (MeC{sub 5}H{sub 4}){sub 3}U(L). Carbon monoxide undergoes migratory insertion into the metal tertiary alkyl bond. The resulting acyl derivative decomposes at 90{degree}C to yield insoluble uranium-containing products and a mixture of tert-butyltoluenes by ring expansion of a methylcyclopentadienyl ligand. Ethylene also undergoes migratory insertionmore » into the metal tertiary alkyl bond. No subsequent insertion of ethylene into the metal carbon bond takes place after the first equivalent has inserted. In marked contrast, reaction of various (MeC{sub 5}H{sub 4}){sub 3}ThX (X = Cl, I, MeC{sub 5}H{sub 4}, O-2,6-Me{sub 2}C{sub 6}H{sub 3}, OTs) compounds with t-BuLi gave intractable materials. However, reaction of the cationic species [(RC{sub 5}H{sub 4}){sub 3}Th](BPh{sub 4}) (R = Me{sub 3}Si, t-Bu) with t-BuLi yields the new thorium hydrides (RC{sub 5}H{sub 4}){sub 3}ThH. 40 refs., 2 figs.« less

Radiogenic Isotopes As Paleoceanographic Tracers in Deep-Sea Corals: Advances in TIMS Measurements of Pb Isotopes and Application to Southern Ocean Corals

NASA Astrophysics Data System (ADS)

Wilson, D. J.; van de Flierdt, T.; Bridgestock, L. J.; Paul, M.; Rehkamper, M.; Robinson, L. F.; Adkins, J. F.

2014-12-01

Deep-sea corals have emerged as a valuable archive of deep ocean paleoceanographic change, with uranium-series dating providing absolute ages and the potential for centennial resolution. In combination with measurements of radiocarbon, neodymium isotopes and clumped isotopes, this archive has recently been exploited to reconstruct changes in ventilation, water mass sourcing and temperature in relation to millennial climate change. Lead (Pb) isotopes in both corals and seawater have also been used to track anthropogenic inputs through space and time and to trace transport pathways within the oceans. Better understanding of the oceanic Pb cycle is emerging from the GEOTRACES programme. However, while Pb isotopes have been widely used in environmental studies, their full potential as a (pre-anthropogenic) paleoceanographic tracer remains to be exploited. In deep-sea corals, challenges exist from low Pb concentrations in aragonite in comparison to secondary coatings, the potential for contamination, and the efficient elemental separation required for measurement by thermal ionisation mass spectrometry (TIMS). Here we discuss progress in measuring Pb isotopes in coral aragonite using a 207Pb-204Pb double spike on a ThermoFinnigan Triton TIMS. For a 2 ng NIST-981 Pb standard, the long term reproducibility (using 1011 Ω resistors) is ~1000 ppm (2 s.d.) on 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios. We now show that using a new 1012 Ω resistor to measure the small 204Pb beam improves the internal precision on these ratios from ~500 ppm (2 s.e.) to ~250 ppm (2 s.e.) and we envisage a potential improvement in the long term reproducibility as a consequence. We further assess the internal precision and external reproducibility of our method using a BCR-2 rock standard and an in-house coral standard. Preliminary evidence on the application of this method to natural samples is derived from cleaning experiments and replication tests on deep-sea corals from the Southern Ocean.

Exploiting the Reactivity of Actinide Fluoride Bonds for the Synthesis of a New Class of Bis(azide) Uranium Complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Karla A.; Lichtscheidl, Alejandro G.; Monreal, Marisa Jennifer

The terminal actinide fluoride bonds in (C 5Me 5) 2ThF 2(py) (py = pyridine) and (C 5Me 5) 2UF 2(O=PR 3) (R = Me, Ph) react with two equivalents of Me 3SiN 3 in toluene to form the polymeric thorium bis(azide), [(C 5Me 5) 2Th(N 3)2] ∞, and a new class of monometallic uranium bis(azide) complexes, (C 5Me 5) 2U(N 3)2(O=PR 3), respectively. Full characterization of the novel complexes (C 5Me 5) 2ThF 2(py) and (C 5Me 5) 2UF 2(O=PR 3) are reported, including the solid-state structures of (C 5Me 5) 2ThF 2(py) and (C 5Me 5) 2U(N 3) 2(O=PPhmore » 3). Lastly, electronic absorption spectral data are also reported for (C 5Me 5) 2AnF 2(py) (An = Th, U) and (C 5Me 5) 2U(N 3) 2(O=PR 3) to confirm metal oxidation state and enable elucidation of the fluoride and azide ligand bonding in these complexes.« less

Exploiting the Reactivity of Actinide Fluoride Bonds for the Synthesis of a New Class of Bis(azide) Uranium Complexes

DOE PAGES

Erickson, Karla A.; Lichtscheidl, Alejandro G.; Monreal, Marisa Jennifer; ...

2017-11-04

The terminal actinide fluoride bonds in (C 5Me 5) 2ThF 2(py) (py = pyridine) and (C 5Me 5) 2UF 2(O=PR 3) (R = Me, Ph) react with two equivalents of Me 3SiN 3 in toluene to form the polymeric thorium bis(azide), [(C 5Me 5) 2Th(N 3)2] ∞, and a new class of monometallic uranium bis(azide) complexes, (C 5Me 5) 2U(N 3)2(O=PR 3), respectively. Full characterization of the novel complexes (C 5Me 5) 2ThF 2(py) and (C 5Me 5) 2UF 2(O=PR 3) are reported, including the solid-state structures of (C 5Me 5) 2ThF 2(py) and (C 5Me 5) 2U(N 3) 2(O=PPhmore » 3). Lastly, electronic absorption spectral data are also reported for (C 5Me 5) 2AnF 2(py) (An = Th, U) and (C 5Me 5) 2U(N 3) 2(O=PR 3) to confirm metal oxidation state and enable elucidation of the fluoride and azide ligand bonding in these complexes.« less

Calculated criticality for sup 235 U/graphite systems using the VIM Monte Carlo code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, P.J.; Grasseschi, G.L.; Olsen, D.N.

1992-01-01

Calculations for highly enriched uranium and graphite systems gained renewed interest recently for the new production modular high-temperature gas-cooled reactor (MHTGR). Experiments to validate the physics calculations for these systems are being prepared for the Transient Reactor Test Facility (TREAT) reactor at Argonne National Laboratory (ANL-West) and in the Compact Nuclear Power Source facility at Los Alamos National Laboratory. The continuous-energy Monte Carlo code VIM, or equivalently the MCNP code, can utilize fully detailed models of the MHTGR and serve as benchmarks for the approximate multigroup methods necessary in full reactor calculations. Validation of these codes and their associated nuclearmore » data did not exist for highly enriched {sup 235}U/graphite systems. Experimental data, used in development of more approximate methods, dates back to the 1960s. The authors have selected two independent sets of experiments for calculation with the VIM code. The carbon-to-uranium (C/U) ratios encompass the range of 2,000, representative of the new production MHTGR, to the ratio of 10,000 in the fuel of TREAT. Calculations used the ENDF/B-V data.« less

Uranium, yttrium, and rare earth elements accumulation during the Cretaceous anoxic events in carbonaceous rocks in the Pacific Ocean

NASA Astrophysics Data System (ADS)

Savelyeva, Olga; Philosofova, Tatyana; Bergal-Kuvikas, Olga; Savelyeva, Svetlana

2017-04-01

We have studied the carbonate-siliceous section of paleooceanic Albian-Cenomanian deposits on the Kamchatsky Mys peninsula (Eastern Kamchatka, Russia) [1].The section is represented by a rhythmic alternation of planktonic limestones and jaspers, accumulated in the open ocean environment. The rhythmicity can be attributed to climate variations that reflect a fluctuation of astronomical parameters (Milankovitch cycles) [2, 3].The section contains two beds enriched in organic carbon, corresponding to the two oceanic anoxic events - MCE and OAE2 [3]. The maximum content of organic matter in those beds reaches 68%. Our geochemical studies revealed an enrichment of the carbonaceous rocks in some major and trace elements including PGE, in comparison with the surrounding limestone and jasper [4].The accumulation of the ore elements in carbonaceous beds is caused by euxinic conditions during sedimentation.The content of uranium, yttrium, and rare earth elements in carbonaceous rocks is up to 60, 142 and 312 ppm respectively. Phosphate grains (bone detritus) with microinclusions of yttrium and uranium minerals were revealed in the carbonaceous rocks using the scanning electron microscope. These data prove the hypothesis of the sorbtion of U and Y by phosphate detritus from seawater. Microprobe analysis also showed an increased content of Cu, Zn, V in some pyrite framboids, which indicates that these elements are fixed in rocks by Fe-sulphide phase or organic matter under euxinic conditions. Our research may bring us closer to understanding the mechanism of syngenetic accumulation of metals in the black shales. This work was supported by the RFBR (No. 16-05-00546). [1] Palechek, T.N., Savelyev, D.P., Savelyeva, O.L. (2010) Stratigraphy and Geological Correlation 18, (1) 63-82. [2] Savelyeva, O.L. (2010). Vestnik Kraunts. Nauki o zemle 1 (15), 45-55 (in Russian). [3] Savelyev, D.P., Savelyeva, O.L., Palechek, T.N., Pokrovsky, B.G. (2012) Geophysical Research Abstracts, 14, EGU2012-1940. [4] Savelyeva, O., Palesskiy, S., Savelyev, D. (2015) Goldschmidt Abstracts, 2015. 2779.

A Record of Uranium-Series Transport in Fractured, Unsaturated Tuff at Nopal I, Sierra Peña Blanca, Chihuahua, Mexico

NASA Astrophysics Data System (ADS)

Denton, J.; Goldstein, S. J.; Paviet, P.; Nunn, A. J.; Amato, R. S.; Hinrichs, K. A.

2015-12-01

In this study we utilize U-series disequilibria measurements to investigate mineral fluid interactions and the role fractures play in the geochemical evolution of an analogue for a high level nuclear waste repository, the Nopal I uranium ore deposit. Samples of fracture-fill materials have been collected from a vertical drill core and surface fractures. High uranium concentrations in these materials (12-7700 ppm) indicate U mobility and transport from the deposit in the past. U concentrations generally decrease with horizontal distance away from the ore deposit but show no trend with depth. Isotopic activity ratios indicate a complicated geochemical evolution in terms of the timing and extent of actinide mobility, possibly due to changing environmental (redox) conditions over the history of the deposit. 234U/238U activity ratios are generally distinct from secular equilibrium and indicate some degree of open system U behavior during the past 1.2 Ma. However, calculated closed system 238U-234U-230Th model ages are generally >313 ka and >183 ka for the surface fracture and drill core samples respectively, suggesting closed system behavior for U and Th over this most recent time period. Whole rock isochrons drawn for the drill core samples show that at two of three depths fractures have remained closed with respect to U and Th mobility for >200 ka. However, open system behavior for U in the last 350 ka is suggested at 67 m depth. 231Pa/235U activity ratios within error of unity suggest closed system behavior for U and Pa for at least the past 185 ka. 226Ra/230Th activity ratios are typically <1 (0.7-1.2), suggesting recent (<8 ka) radium loss and mobility due to ongoing fluid flow in the fractures. Overall, the mainly closed system behavior of U-Th-Pa over the past ~200 ka provides one indicator of the geochemical immobility of these actinides over long time-scales for potential nuclear waste repositories sited in fractured, unsaturated tuff.

77 FR 27130 - Ametoctradin; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-09

...; grape at 5.0 ppm; grape, raisin at 8 ppm; hop, dried cones at 9 ppm; onion, bulb, subgroup 3-07A at 1.2 ppm; onion, green, subgroup 3-07B at 16 ppm; vegetable, cucurbit, group 9 at 4.5 ppm; vegetable... 50 ppm; grape at 4.0 ppm; grape, raisin at 8.0 ppm; hop, dried cones at 10 ppm; onion, bulb, subgroup...

Systemic effects of H2S inhalation at human equivalent dose of pathologic halitosis on rats.

PubMed

Yalçın Yeler, Defne; Aydin, Murat; Gül, Mehmet; Hocaoğlu, Turgay; Özdemir, Hakan; Koraltan, Melike

2017-10-01

Halitosis is composed by hundreds of toxic gases. It is still not clear whether halitosis gases self-inhaled by halitosis patients cause side effects. The aim of the study was to investigate the effect of H 2 S inhalation at a low concentration (human equivalent dose of pathologic halitosis) on rats. The threshold level of pathologic halitosis perceived by humans at 250 ppb of H 2 S was converted to rat equivalent concentration (4.15 ppm). In the experimental group, 8 rats were exposed to H 2 S via continuous inhalation but not the control rats. After 50 days, blood parameters were measured and tissue samples were obtained from the brain, kidney and liver and examined histopathologically to determine any systemic effect. While aspartate transaminase, creatine kinase-MB and lactate dehydrogenase levels were found to be significantly elevated, carbondioxide and alkaline phosphatase were decreased in experimental rats. Other blood parameters were not changed significantly. Experimental rats lost weight and became anxious. Histopathological examination showed mononuclear inflammatory cell invasion in the portal areas, nuclear glycogen vacuoles in the parenchymal area, single-cell necrosis in a few foci, clear expansion in the central hepatic vein and sinusoids, hyperplasia in Kupffer cells and potential fibrous tissue expansion in the portal areas in the experimental rats. However, no considerable histologic damage was observed in the brain and kidney specimens. It can be concluded that H 2 S inhalation equivalent to pathologic halitosis producing level in humans may lead to systemic effects, particularly heart or liver damage in rats.

Evaluation of fuel-borne sodium effects on a DOC-DPF-SCR heavy-duty engine emission control system: Simulation of full-useful life

DOE PAGES

Lance, Michael J.; Wereszczak, Andrew A; Toops, Todd J.; ...

2016-10-17

Here we report that for renewable fuels to displace petroleum, they must be compatible with emissions control devices. Pure biodiesel contains up to 5 ppm Na + K and 5 ppm Ca + Mg metals, which have the potential to degrade diesel emissions control systems. This study aims to address these concerns, identify deactivation mechanisms, and determine if a lower limit is needed. Accelerated aging of a production exhaust system was conducted on an engine test stand over 1001 h using 20% biodiesel blended into ultra-low sulfur diesel (B20) doped with 14 ppm Na. This Na level is equivalent tomore » exposure to Na at the uppermost expected B100 value in a B20 blend for the system full-useful life. During the study, NOx emissions exceeded the engine certification limit of 0.33 g/bhp-hr before the 435,000-mile requirement. Replacing aged diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) devices with new degreened parts showed that each device contributed equally to the NOx increase. Following this systems-based evaluation, a detailed investigation of the individual components was completed. Na was determined to have minimal impact on DOC activity. For this system, it is estimated that B20-Na resulted in 50% more ash into the DPF. However, the Na did not diffuse into the cordierite DPF nor degrade its mechanical properties. The SCR degradation was found to be caused by a small amount of precious group metals (PGM) contamination that increased NH3 oxidation, and lowered NOx reduction. Therefore, we determined that the primary effect of Na in this study is through increased ash in the DPF rather than deactivation of the catalytic activity.« less

Evaluation of fuel-borne sodium effects on a DOC-DPF-SCR heavy-duty engine emission control system: Simulation of full-useful life

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lance, Michael J.; Wereszczak, Andrew A; Toops, Todd J.

Here we report that for renewable fuels to displace petroleum, they must be compatible with emissions control devices. Pure biodiesel contains up to 5 ppm Na + K and 5 ppm Ca + Mg metals, which have the potential to degrade diesel emissions control systems. This study aims to address these concerns, identify deactivation mechanisms, and determine if a lower limit is needed. Accelerated aging of a production exhaust system was conducted on an engine test stand over 1001 h using 20% biodiesel blended into ultra-low sulfur diesel (B20) doped with 14 ppm Na. This Na level is equivalent tomore » exposure to Na at the uppermost expected B100 value in a B20 blend for the system full-useful life. During the study, NOx emissions exceeded the engine certification limit of 0.33 g/bhp-hr before the 435,000-mile requirement. Replacing aged diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) devices with new degreened parts showed that each device contributed equally to the NOx increase. Following this systems-based evaluation, a detailed investigation of the individual components was completed. Na was determined to have minimal impact on DOC activity. For this system, it is estimated that B20-Na resulted in 50% more ash into the DPF. However, the Na did not diffuse into the cordierite DPF nor degrade its mechanical properties. The SCR degradation was found to be caused by a small amount of precious group metals (PGM) contamination that increased NH3 oxidation, and lowered NOx reduction. Therefore, we determined that the primary effect of Na in this study is through increased ash in the DPF rather than deactivation of the catalytic activity.« less

Absorption, Distribution and Excretion of Four Forms of Titanium Dioxide Pigment in the Rat.

PubMed

Farrell, Thomas P; Magnuson, Berna

2017-08-01

Titanium dioxide (TiO 2 ) is a white color additive that has a long history of global approval and use in food. There is, however, considerable confusion regarding the applicability of the biological effects of novel, engineered, nano-sized forms of TiO 2 developed for nonpigmentary applications to the safety of oral exposure to food grade TiO 2 pigment. The objective of this study was to assess the absorption, distribution, and routes of excretion in rats after oral exposure to food grade TiO 2 . Four different grades of TiO 2 (200 ppm) or control (0 ppm) diets were fed to rats for 7 consecutive days, followed by control diet only for 1, 24, or 72 h. Concentrations of titanium in liver, kidney and muscle were mainly below the limit of detection (<0.1 to < 0.2 mg/kg wet weight); tissue concentrations of titanium above the LOD were in the range of 0.1 to 0.3 mg/kg wet weight for all groups. Whole blood concentrations of titanium were <0.04 mg/L for all groups. Urinary excretion of titanium was equivalent to <2% daily dose/L of urine for all groups and was generally below the limit of quantification (<0.04 mg/L). Feces represented the predominant route of excretion. These results demonstrate that there is no accumulation of titanium in tissues following consumption of diets containing 200 ppm food grade TiO 2 . No differences in systemic absorption of the 4 forms of TiO 2 were observed indicating that the bioavailability of TiO 2 is consistently low for the range of particle sizes and morphologies examined in this study. © 2017 Institute of Food Technologists®.

Anomalously Strong and Rapid Drying of the Tropical Lower Stratosphere in 2016: Connections to Both the QBO and ENSO

NASA Astrophysics Data System (ADS)

Hurst, D. F.; Davis, S. M.; Rosenlof, K. H.; Lambert, A.; Read, W. G.; Hall, E.; Jordan, A. F.

2017-12-01

Variations in tropical lower stratospheric water vapor are generally attributable to annual cycles in the Brewer-Dobson circulation and inter-annual phenomenon like the quasi-biennial oscillation (QBO) and the El Niño Southern Oscillation (ENSO). Extremes in tropical lower stratospheric water vapor (SWV) occur when these annual and inter-annual changes are constructively superimposed. The atypical progression of the 2015-16 QBO led to a strong and rapid cooling of the tropical lower stratosphere during 2016. From December 2015 to November 2016, monthly tropical mean (15°S-15°N) coldpoint temperature (CPT) anomalies decreased 3.2°C, from 1.1 to -2.1°C. Accordingly, monthly tropical mean SWV anomalies at 83 hPa dropped 1.9 ppm, from 0.85 to -1.05 ppm. This decline in SWV anomalies is equivalent to 40% of the long-term December average tropical abundance of SWV at 83 hPa. The 2016 decreases in tropical anomalies of both CPTs and SWV were not zonally uniform, with average Eastern Hemisphere reductions greater by 2°C and 0.9 ppm (50%), respectively. Since the QBO typically has a zonally uniform effect on tropical CPTs, this implies a zonally non-uniform mechanism like ENSO also influenced CPTs during 2016. The transition of ENSO from strong El Niño to weak La Niña conditions in 2016 would induce this zonal non-uniformity by shifting convective activity from the Eastern Pacific to the Western Pacific and Indian Ocean regions. Evidence indicates the simultaneous cooling of tropical CPTs by both the QBO and ENSO during 2016 rapidly dried the tropical lower stratosphere with anomalous strength, especially in the Eastern Hemisphere.

77 FR 30481 - Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or on Various...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-23

... Brassica vegetables) (crop group 4) at 15 ppm; milk at 0.01 ppm; milk, fat at 0.04 ppm; oilseeds, except...) at 8 ppm; cattle, fat at 0.01 ppm; cattle, liver at 0.04 ppm; cattle, meat at 0.01 ppm; cattle, meat... group 8-10) at 2 ppm; goat, fat at 0.01 ppm; goat, liver at 0.04 ppm; goat, meat at 0.01 ppm; goat, meat...

77 FR 32401 - 2,6-Diisopropylnaphthalene (2,6-DIPN) and Its Metabolites and Degradates; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-01

... 5.5 parts per million (ppm); potato, wet peel at 6.0 ppm; potato, whole at 2.0 ppm; cattle, fat at 0.2 ppm; cattle, meat at 0.02 ppm; cattle, meat byproducts, except fat at 0.02 ppm; goat, fat at 0.2 ppm; goat, meat at 0.02 ppm; goat, meat byproducts, except fat at 0.02 ppm; horse, fat at 0.2 ppm...

Hydrogen-fueled diesel engine without timed ignition

NASA Technical Reports Server (NTRS)

Homan, H. S.; De Boer, P. C. T.; Mclean, W. J.; Reynolds, R. K.

1979-01-01

Experiments were carried out to investigate the feasibility of converting a diesel engine to hydrogen-fueled operation without providing a timed ignition system. Use was made of a glow plug and a multiple-strike spark plug. The glow plug was found to provide reliable ignition and smooth engine operation. It caused the hydrogen to ignite almost immediately upon the start of injection. Indicated mean effective pressures were on the order of 1.3 MPa for equivalence ratios between 0.1 and 0.4 at a compression ratio of 18. This is significantly higher than the corresponding result obtained with diesel oil (about 0.6 MPa for equivalence ratios between 0.3 and 0.9). Indicated thermal efficiencies were on the order of 0.4 for hydrogen and 0.20-0.25 for diesel oil. Operation with the multiple-strike spark system yielded similar values for IMEP and efficiency, but gave rise to large cycle-to-cycle variations in the delay between the beginning of injection and ignition. Large ignition delays were associated with large amplitude pressure waves in the combustion chamber. The measured NO(x) concentrations in the exhaust gas were of the order of 50-100 ppm. This is significantly higher than the corresponding results obtained with premixed hydrogen and air at low equivalence ratios. Compression ignition could not be achieved even at a compression ratio of 29.

Defining treatment conditions for pulsed electric field pasteurization of apple juice.

PubMed

Saldaña, G; Puértolas, E; Monfort, S; Raso, J; Alvarez, I

2011-11-15

The influence of temperature and the presence of N(α)-lauroyl ethylester (ethyl lauroyl arginate, LAE) on the inactivation caused by continuous pulsed electric field treatments (PEF) in Escherichia coli O157:H7 suspended in apple juice have been investigated to define treatment conditions applicable at industrial scale that promote an equivalent safety level when compared with thermal processing. In the range of experimental conditions investigated (outlet temperature: 20-40 °C, electric field strength: 20-30 kV, treatment time: 5-125 μs) at outlet temperatures equal or lower than 55±1 °C, the inactivation of E. coli O157:H7 treated in apple juice ranged from 0.4 to 3.6 Log₁₀ cycles reduction and treated in apple juice supplemented with LAE (50 ppm) ranged from 0.9 to 6.7 Log₁₀ cycles reduction. An empirical mathematical model was developed to estimate the treatment time and total specific energy input to obtain 5 Log₁₀ cycles reduction in the population of E. coli O157:H7 suspended in apple juice supplemented with 50 ppm of LAE at different electric field strengths and inlet temperatures. Treatment conditions established for E. coli O157:H7 were validated with other PEF resistant Gram-positive (Listeria monocytogenes, and Staphylococcus aureus) and Gram-negative (Salmonella enterica serovar Typhimurium) strains. When the treatment was applied to the apple juice, a treatment of 25 kV/cm for 63 μs corresponding with an outlet temperature of 65 °C and input energy of 125 kJ/kg was required to achieve more than 5 Log₁₀ cycles in the four strains investigated. The addition of LAE reduced the treatment time required to obtain an equivalent inactivation (>5 Log₁₀ cycles) in the four microorganisms to 38.4 μs, the outlet temperature to 55 °C, and the input energy to 83.2 kJ/kg. Copyright © 2011 Elsevier B.V. All rights reserved.

Relationships between ground and airborne gamma-ray spectrometric survey data, North Ras Millan, Southern Sinai Peninsula, Egypt.

PubMed

Youssef, Mohamed A S

2016-02-01

In the last decades of years, there was considerable growth in the use of airborne gamma-ray spectrometry. With this growth, there was an increasing need to standardize airborne measurements, so that they can be independent of survey parameters. Acceptable procedures were developed for converting airborne to ground gamma-ray spectrometric measurements of total-count intensity as well as, potassium, equivalent uranium and equivalent thorium concentrations, due to natural sources of radiation. The present study aims mainly to establish relationships between ground and airborne gamma-ray spectrometric data, North Ras Millan, Southern Sinai Peninsula, Egypt. The relationships between airborne and ground gamma-ray spectrometric data were deduced for the original and separated rock units in the study area. Various rocks in the study area, represented by Quaternary Wadi sediments, Cambro-Ordovician sandstones, basic dykes and granites, are shown on the detailed geologic map. The structures are displayed, which located on the detailed geologic map, are compiled from the integration of previous geophysical and surface geological studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative toxicity effect of bush tea leaves (Hyptis suaveolens) and orange peel (Citrus sinensis) oil extract on larvae of the yellow fever mosquito Aedes aegypti.

PubMed

Amusan, A A S; Idowu, A B; Arowolo, F S

2005-09-01

The ethanolic extracts of the orange peel (Citrus sinensis) and bush tea leaves (Hyptis suaveolens) were compared for their toxicity effect on the larvae of the yellow fever mosquito Aedes aegypti collected from disused tyres beside College of Natural Sciences building University of Agriculture, Abeokuta, Nigeria. Eight graded concentrations, 0.9ppm, 0.8ppm, 0.7ppm, 0.6ppm, 0.5ppm, 0.4ppm, 0.3ppm and 0.2ppm of both plant extracts were tested on the larvae. The mean lethal dose LD10, was 0.15 ppm for C. sinensis, 0.01 for H. suaveolens, while LD50 for C. sinensis was 0.4ppm, H. suaveolens 0.60ppm and LD90 for C. sinensis was 0.9ppm and H. suaveolens was 1.45ppm. LD10 for the control 0.65ppm, LD50 0.9ppm and LD90 2.0 ppm. The extract of C. sinensis peel caused higher mortality rate at concentrations 0.8ppm (95%) and 0.3ppm (90%) of the larvae while the extract of H. suaveolens caused high mortality rate on the larvae at concentrations of 0.9ppm (80%) and 0.3ppm (80%). Significant differences were observed between untreated and treated larvae (exposed to either of the extract) at the various concentrations (P< 0.05).

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...) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The term uranium feed or natural uranium feed means natural uranium in the form of UF6 suitable for uranium...

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...) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.317 Uranium feed; natural uranium feed. The term uranium feed or natural uranium feed means natural uranium in the form of UF6 suitable for uranium...

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.

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.

75 FR 35801 - Notice of Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-23

....05 ppm; grass, hay at 0.05 ppm; and grass, forage at 1.5 ppm. An enforcement method for plants has...; sorghum, stover at 0.35 ppm; grass, hay at 2.5 ppm; and grass, forage at 10 ppm. The analytical method is... on sorghum, grain at 0.2 ppm; grass, hay at 5.0 ppm; and grass, forage at 18 ppm. Since bromoxynil...

Case studies of hydrogen sulphide occupational exposure incidents in the UK.

PubMed

Jones, Kate

2014-12-15

The UK Health and Safety Executive has investigated several incidents of workplace accidents involving hydrogen sulphide exposure in recent years. Biological monitoring has been used in some incidents to determine the cause of unconsciousness resulting from these incidents and as a supporting evidence in regulatory enforcement. This paper reports on three case incidents and discusses the use of biological monitoring in such cases. Biological monitoring has a role in identifying hydrogen sulphide exposure in incidents, whether these are occupational or in the wider environment. Sample type, time of collection and sample storage are important factors in the applicability of this technique. For non-fatal incidents, multiple urine samples are recommended at two or more time points between the incident and 15 h post-exposure. For routine occupational monitoring, post-shift samples should be adequate. Due to endogenous levels of urinary thiosulphate, it is likely that exposures in excess of 12 ppm for 30 min (or 360 ppm/min equivalent) would be detectable using biological monitoring. This is within the Acute Exposure Guideline Level 2 (the level of the chemical in air at or above which there may be irreversible or other serious long-lasting effects or impaired ability to escape) for hydrogen sulphide. Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.

Quantitative patch and repeated open application testing in hydroxyisohexyl 3-cyclohexene carboxaldehyde sensitive-patients.

PubMed

Schnuch, Axel; Uter, Wolfgang; Dickel, Heinrich; Szliska, Christiane; Schliemann, Sibylle; Eben, Ricarda; Ruëff, Franziska; Gimenez-Arnau, Ana; Löffler, Harald; Aberer, Werner; Frambach, Yvonne; Worm, Margitta; Niebuhr, Margarete; Hillen, Uwe; Martin, Vera; Jappe, Uta; Frosch, Peter J; Mahler, Vera

2009-09-01

To identify the concentration of the fragrance compound hydroxyisohexyl 3-cyclohexene carboxaldehyde (INCI) (HICC) that is sufficiently low not to cause an allergic reaction in patients with proven sensitization. Repeated open application testing (ROAT) in 64 subjects with 2 preparations (perfume and cream) in different concentration (0.005-2.5%). Confirmatory patch testing with four preparations in two different concentrations (2.5% and 5%). The concentrations of HICC being tolerated by 90% of those sensitized to HICC are estimated as <88.2 ppm (cream) and <270 ppm (perfume) equivalent to 1.2 microg/cm(2) (perfume) and 4.9 microg/cm(2) (cream). Patch test preparations differed with regard to sensitivity (88.5-98.1%) and specificity (37.5-87.5%) against the ROAT result as external criterion. ROAT concentrations and the reaction strength in patch testing were inversely correlated (Kendall's tau-b: 0.69), both indicating the existence of different degrees of susceptibility. To protect 90% (50%) of people sensitized, the use concentration should be in the range of 0.009-0.027% (0.18-0.34%), depending on the product type. Taking into account these results, excessive concentrations should be avoided, as this would continue to sensitize people. Close monitoring is indispensable to prove the efficacy of any recommendations aiming to prevent induction.

Application of high-angle annular dark field scanning transmission electron microscopy, scanning transmission electron microscopy-energy dispersive X-ray spectrometry, and energy-filtered transmission electron microscopy to the characterization of nanoparticles in the environment.

PubMed

Utsunomiya, Satoshi; Ewing, Rodney C

2003-02-15

A major challenge to the development of a fundamental understanding of transport and retardation mechanisms of trace metal contaminants (<10 ppm) is their identification and characterization at the nanoscale. Atomic-scale techniques, such as conventional transmission electron microscopy, although powerful, are limited by the extremely small amounts of material that are examined. However, recent advances in electron microscopy provide a number of new analytical techniques that expand its application in environmental studies, particularly those concerning heavy metals on airborne particulates or water-borne colloids. High-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-energy-dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM) can be effectively used to identify and characterize nanoparticles. The image contrast in HAADF-STEM is strongly correlated to the atomic mass: heavier elements contribute to brighter contrast. Gold nanocrystals in pyrite and uranium nanocrystals in atmospheric aerosols have been identified by HAADF-STEM and STEM-EDX mapping and subsequently characterized by high-resolution TEM (HRTEM). EFTEM was used to identify U and Fe nanocrystals embedded in an aluminosilicate. A rare, As-bearing nanophase, westerveldite (FeAs), was identified by STEM-EDX and HRTEM. The combined use of these techniques greatly expands the effective application of electron microscopy in environmental studies, especially when applied to metals of very low concentrations. This paper describes examples of how these electron microbeam techniques can be used in combination to characterize a low concentration of heavy metals (a few ppm) on nanoscale particles.

Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

NASA Astrophysics Data System (ADS)

Perama, Yasmin Mohd Idris; Rashid, Nur Shahidah Abdul; Majid, Amran Ab.; Siong, Khoo Kok

2017-01-01

Human exposure to natural radioactive uranium has been a great interest as more industrial rapidly growing contributes to radiation risks. The aim of this case study was to determine the internal dose in humans incorporated with ingestion of 238U contaminated soils. A gastrointestinal analogue test was employed to simulate the human digestive tract. In-vitro approach via German DIN 19738 model was developed in order to estimate the internal exposure of 238U due to ingestion of different types of soils. Synthetic gastrointestinal fluids assay via in-vitro method were produced to determine the concentration of 238U in various soils using ICP-MS. Based on the results, concentration of 238U in BRIS, laterite, peat and alluvium soils were in ranged between (0.0061 ± 0.0057 - 0.0488 ± 0.0148) ppm and (0.0005 ± 0.0004 - 0.0046 ± 0.0007) ppm in gastric and gastrointestinal phase respectively. Types of soil compositions and pH medium were some of the factors that influence mobilization and solubility of 238U contaminanted soil into the digestive juices that resembles human gastrointestinal tract. For the purpose of internal dose assessment, the committed efective dose from 238U intake in soils ranged between 1.237 × 10-11 - 9.8993 × 10-11 Sv y-1 for gastric phase and 1.0184 × 10-12 - 9.3294 × 10-12 Sv y-1 for gastric-intestinal phase. The internal dose measurements from this study were much lower from the recommended values. Hence, ingestion of 238U contaminated soils would not be expected to pose major health risk to humans.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Broxton, D.E.

A total of 338 water and 1877 sediment samples were collected over a 20,700-km/sup 2/ area from 2125 locations at a nominal density of one sample per 10 km/sup 2/. Water samples were collected from wells, streams, springs, and artificial ponds. Sediment samples were collected from streams, springs, natural ponds, and artificial ponds. Arbitrary anomaly thresholds of two standard deviations above the mean were chosen for both water and sediment sample populations. The U concentrations in waters collected in the Tularosa quadrangle range from below the detection limit of 0.2 parts per billion (ppB) to 57.8 ppB. Most clusters ofmore » water samples containing anomalously high uranium concentrations were collected from locations in uplifts underlain either by volcanic rocks of the mid-Tertiary Datil group or by sedimentary rocks of late Paleozoic and Mesozoic age. Other groups of anomalous waters are from wells that tap Cenozoic aquifers in the intermontane basins. In those areas where the water-sample location coverage is adequate, the known U occurrences are generally associated with high or anomalous U concentrations in water samples. With the exception of one sample with a U concentration of 67.7 ppM, sediments collected in this study have U concentrations that range between 0.2 and 15.2 ppM. Most sediments with U concentrations above the arbitrary anomaly threshold value are from locations which occur in or parallel outcrops of Precambrian crystalline rock exposed in the San Andres and Oscura Mountains. Other anomalous sediments occur as more discreet groups in areas underlain by mid-Tertiary volcanic rocks of the Datil group. Several anomalous samples from the Mogollon-Datil volcanic field were collected along ring fracture systems that surround large volcanic cauldrons.« less

Estimate of radiation release from MIT reactor with un-finned LEU core during Maximum Hypothetical Accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Kaichao; Hu, Lin-wen; Newton, Thomas

2017-05-01

The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. At 6 MW, it delivers neutron flux and energy spectrum comparable to light water reactor (LWR) power reactors in a compact core using highly enriched uranium (HEU) fuel. In the framework of nonproliferation policy, the international community aims to minimize the use of HEU in civilian facilities. Within this context, research and test reactors have started a program to convert HEU fuel to low enriched uranium (LEU) fuel. A new type of LEU fuel basedmore » on a high density alloy of uranium and molybdenum (U-10Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MITR. The current study focuses on the impacts of MITR Maximum Hypothetical Accident (MHA), which is also the Design Basis Accident (DBA), with LEU fuel. The MHA for the MITR is postulated to be a coolant flow blockage in the fuel element that contains the hottest fuel plate. It is assumed that the entire active portion of five fuel plates melts. The analysis shows that, within a 2-h period and by considering all the possible radiation sources and dose pathways, the overall off-site dose is 302.1 mrem (1 rem ¼ 0.01 Sv) Total Effective Dose Equivalent (TEDE) at 8 m exclusion area boundary (EAB) and a higher dose of 392.8 mrem TEDE is found at 21 m EAB. In all cases the dose remains below the 500 mrem total TEDE limit goal based on NUREG-1537 guidelines.« less

Hazelwood Interim Storage Site: Annual site environment report, Calendar year 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-11-01

The Hazelwood Interim Storage Site (HISS) is presently used for the storage of low-level radioactively contaminated soils. Monitoring results show that the HISS is in compliance with DOE Derived Concentration Guides (DCGs) and radiation protection standards. During 1985, annual average radon concentrations ranged from 10 to 23% of the DCG. The highest external dose rate at the HISS was 287 mrem/yr. The measured background dose rate for the HISS area is 99 mrem/yr. The highest average annual concentration of uranium in surface water monitored in the vicinity of the HISS was 0.7% of the DOE DCG; for /sup 226/Ra itmore » was 0.3% of the applicable DCG, and for /sup 230/Th it was 1.7%. In groundwater, the highest annual average concentration of uranium was 12% of the DCG; for /sup 226/Ra it was 3.6% of the applicable DCG, and for /sup 230/Th it was 1.8%. While there are no concentration guides for stream sediments, the highest concentration of total uranium was 19 pCi/g, the highest concentration of /sup 226/Ra was 4 pCi/g, and the highest concentration of /sup 230/Th was 300 pCi/g. Radon concentrations, external gamma dose rates, and radionuclide concentrations in groundwater at the site were lower than those measured in 1984; radionuclide concentrations in surface water were roughly equivalent to 1984 levels. For sediments, a meaningful comparison with 1984 concentrations cannot be made since samples were obtained at only two locations and were only analyzed for /sup 230/Th. The calculated radiation dose to the maximally exposed individual at the HISS, considering several exposure pathways, was 5.4 mrem, which is 5% of the radiation protection standard.« less

Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rotsch, David A.; Brossard, Tom; Roussin, Ethan

Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABOmore » were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.« less

78 FR 70864 - Metaldehyde; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-27

... plus cob with husks removed at 0.05 ppm; grass, forage at 1.5 ppm; grass, hay at 1.8 ppm; leaf petioles...: ``Metaldehyde; Human Health Risk Assessment for Proposed Uses on Grass Grown for Seed, Leaf Petioles [Crop....10 ppm; grass, forage from 1.5 ppm to 2.0 ppm; grass, hay from 1.8 ppm to 2.0 ppm; leaf petioles...

The association of uranium with organic matter in Holocene peat: An experimental leaching study

USGS Publications Warehouse

Zielinski, R.A.; Meier, A.L.

1988-01-01

Uraniferous peat was sampled from surface layers of a Holocene U deposit in northeastern Washington State. Dried, sized, and homogenized peat that contained 5980 ??307 ppm U was subjected to a variety of leaching conditions to determine the nature and strength of U-organic bonding in recently accumulated organic matter. The results complement previous experimental studies of U uptake on peat and suggest some natural or anthropogenic disturbances that are favorable for remobilizing U. The fraction of U leached in 24 h experiments at 25??C ranged from 0 to 95%. The most effective leach solutions contained anions capable of forming stable dissolved complexes with uranyl (UO2+2) cation. These included H2SO4 (pH = 1.5) and concentrated (>0.01 M) solutions of sodium bicarbonate-carbonate (pH = 7.0-10.0), or sodium pyrophosphate (pH = 10). Effective leaching by carbonate and pyrophosphate in the absence of added oxidant, and the insignificant effect of added oxidant (as pressurized O2) strongly suggest that U is initially fixed on organic matter as an oxidized U(VI) species. Uranium is more strongly bound than some other polyvalent cations, based on its resistance to exchange in the presence of large excesses of dissolved Ca2+ and Cu2+. Measurements of the rate of U leaching indicate faster rates in acid solution compared to carbonate solution, and are consisten with simultaneous attack of sites with different affinities for U. Sulfuric acid appears a good choice for commercial extraction of U from mined peat. In situ disturbances such as overliming of peat soils, addition of fertilizers containing pyrophosphate, or incursions of natural carbonate-rich waters could produce significant remobilization of U, and possibly compromise the quality of local domestic water supplies. ?? 1988.

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.

77 FR 14291 - Penthiopyrad; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-09

...-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamide) in animal commodities hog, meat at 0.01 ppm; hog, fat...; cattle, meat at 0.05 ppm; cattle, fat at 0.05 ppm; cattle, liver at 0.2 ppm; cattle, kidney at 0.1 ppm; cattle, meat byproducts at 0.2 ppm; sheep, meat at 0.01 ppm; sheep, fat at 0.02 ppm; sheep, liver at 0.05...

[Limonoids in Phellodendron amurense (Kihada)].

PubMed

Miyake, M; Inaba, N; Ayano, S; Ozaki, Y; Maeda, H; Ifuku, Y; Hasegawa, S

1992-05-01

Limonoids and their glucosides in the seeds and barks of Phellondendron amurense (Kihada) were analyzed. The seeds contained limonin (1950 ppm), obakunone (20 ppm), limonin 17-beta-D-glucopyranoside (820 ppm) and obakunone 17-beta-D-glucopyranoside (1360 ppm). The barks contained limonin (6760 ppm), obakunone (1240 ppm) and nomilin (270 ppm).

Pyrochlore-rich titanate ceramics for the immobilization of plutonium: redox effects on phase equilibria in cerium- and thorium- substituted analogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryerson, F J; Ebbinghaus, B

2000-05-25

Three compositions representing plutonium-free analogs of a proposed Ca-Ti-Gd-Hf-U-PU oxide ceramic for the immobilization of plutonium were equilibrated at 1 atm, 1350 C over a range of oxygen fugacities between air and that equivalent to the iron-wuestite buffer. The cerium analog replaces Pu on a mole-per-mole basic with Ce; the thorium analog replaces Pu with Th. A third material has 10 wt% Al{sub 2}O{sub 3} added to the cerium analog to encourage the formation of a Hf-analog of, CaHfTi{sub 2}O{sub 7}, zirconolite, which is referred to as hafnolite. The predominant phase produced in each formulation under all conditions is pyrochlore,more » A{sub 2}T{sub 2}O{sub 7}, where the T site is filled by Ti, and Ca, the lanthanides, Hf, U and Pu are accommodated on the A-site. Other lanthanide and uranium-bearing phases encountered include brannerite (UTi{sub 2}O{sub 6}), hafnolite (CaHfTi{sub 2}O{sub 7}), perovskite (CaTiO{sub 3}) and a calcium-lanthanide aluminotitanate with nominal stoichiometry (Ca,Ln)Ti{sub 2}Al{sub 9}O{sub 19}, where Ln is a lanthanide. The phase compositions show progressive shifts with decreasing oxygen fugacity. All of the phases observed have previously been identified in titanate-based high-level radioactive waste ceramics and demonstrate the flexibility of these ceramics to variations in processing parameters. The main variation is an increase in the uranium concentrations of pyrochlore and brannerite which must be accommodated by variations in modal abundance. Pyrochlore compositions are consistent with existing spectroscopic data suggesting that uranium is predominantly pentavalent in samples synthesized in air. A simple model based on ideal stoichiometry suggests the U{sup +4}/{Sigma}U varies linearly with log fO{sub 2} and that all of the uranium is quadravalent at the iron-wuestite buffer.« less

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-generated radon hazards. We conclude with a recommendation that radon as arising from artefacts and ornaments is considered appropriately in radon protocols and guidelines.

The study of equivalent dose of uranium in long bean (V. U. Sesquipedalis) and the effect on human

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashid, Nur Shahidah Abdul; Yoshandi, Tengku Mohammad; Majid, Sukiman Sarmania Amran Ab.

In the case of accidental release of Uranium-238 ({sup 238}U) radionuclides in a nuclear facility or in the environment, internal contamination by either acute or chronic exposure has the potential to induce both radiological and chemical toxic effects. A study was conducted to estimate the {sup 238}U radionuclide concentration in the long beans using Induced Coupled Mass Plasma-Spectrometry (ICP-MS). {sup 238}U radionuclide is a naturally occurring radioactive material that can be found in soil and can be transferred to the long bean (Vigna unguiculata subsp. Sesquapedalis) directly or indirectly via water or air. Kidney and liver are the major sitesmore » of deposition of {sup 238}U radionuclide. The obtained dose exposed in the liver and kidney is used to assess the safety level for public intake of {sup 238}U radionuclide from the consumption of long beans. The concentration of {sup 238}U radionuclide measured in long bean samples was 0.0226 ± 0.0009 mg/kg. Total activity of {sup 238}U radionuclide was 0.0044 ± 0.0002 Bq/day with the daily intake of 0.3545 ± 0.0143 µg/day and the annual committed effective dose due to ingestion of {sup 238}U radionuclide in long beans was 0.2230 ± 0.0087 µSv/year. The committed equivalent dose of {sup 238}U radionuclide from the assessment in the liver and kidney are 0.4198 ± 0.0165 nSv and 10.9335 ± 0.4288 nSv. The risk of cancer of {sup 238}U radionuclide was determined to be (86.0466 ± 3.3748) × 10-9. Thus, the results concluded that {sup 238}U radionuclide in local long beans was in the permitted level and safe to consume without posing any significant radiological threat to population.« less

The biodegradation of crude oil in the deep ocean.

PubMed

Prince, Roger C; Nash, Gordon W; Hill, Stephen J

2016-10-15

Oil biodegradation at a simulated depth of 1500m was studied in a high-pressure apparatus at 5°C, using natural seawater with its indigenous microbes, and 3ppm of an oil with dispersant added at a dispersant:oil ratio of 1:15. Biodegradation of the detectable hydrocarbons was prompt and extensive (>70% in 35days), although slower by about a third than under otherwise identical conditions equivalent to the surface. The apparent half-life of biodegradation of the total detectable hydrocarbons at 15MPa was 16days (compared to 13days at atmospheric pressure), although some compounds, such as the four-ring aromatic chrysene, were degraded rather more slowly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impedimetric detection of alcohol vapours using nanostructured zinc ferrite.

PubMed

Kannan, Padmanathan Karthick; Saraswathi, Ramiah

2014-11-01

A comparative study on the sensing characteristics of nanostructured zinc ferrite to three primary alcohols viz. methanol, ethanol and propanol has been carried out. The zinc ferrite has been prepared by a combustion method and characterized by XRD, FTIR, AFM and SEM. Impedance studies in the alcohol concentration range varying from 100 to 1000 ppm show definite variations in response to both the nature of the alcohol and its concentration. The nanostructured zinc ferrite shows the highest sensor response to methanol and least to propanol. Equivalent circuit modelling and calibration have been made for all the three alcohol sensors. The material shows a better selectivity to the alcohols compared to formaldehyde, ammonia and acetone vapours. Copyright © 2014 Elsevier B.V. All rights reserved.

New Discoveries of Trr and Radiopactive Elements of Phosphogypsum from Romania

NASA Astrophysics Data System (ADS)

Maruta Iancu, Aurora; Georgeta Dumitras, Delia; Marincea, Stefan

2014-05-01

Phosphogypsum is a technogenic product remaining after the extraction of phosphoric acid from raw phosphate, mainly apatite. Some radioactive elements presented in the phosphate original rock, consisting in apatit, are Ra-226, th-232, U-238, Pb-210, Po-240, K-210, that can be also found in the phosphogypsum. Determination of elements has been carried out on phosphogypsum samples from Turnu Magurele (TR), Valea Calugareasca (VC), Navodari (N) and Bacau (B). The most important minor elements of phosphogypsum are Th and U. The radioactivity of isotopes from Bacau samples of phosphogypsum is: U-238 exceeding (ppm) - 40,50; 31,96; 17,49; 30,00; 31,00 and Th-232 (ppm) - 8,07; 6,07; 6,41; 7,80; 6,41. The radiometric analyzes confirmed that Bacau county phosphogypsum have higher concentrations of U, while the content in Th is lower. The radioactivity of isotopes from samples of Navodari phosphogypsum is U-238 (ppm) - 37,00; 40,97; 10,84; 25,72 and Th-232 (ppm) - 6,82; 7,04; 6,19; 7,55. The radioactivity of isotopes from Turnu Magurele phosphogypsum samples is: U-232 (ppm) - 1,51; 21,92; 28,71; 6,92, 10,79, 11,00, and Th 232 (ppm) - 3,87; 7,29; 10,65; 6,22; 6,77; 5,45. The radiaoactivity of isotopes from Valea Calugareasca samples of phosphogypsum is: U-238 (ppm) - 17,60; 22,35; 17,93; 18,78 and Th-232 (ppm) - 5,98; 7,12; 7,85; 8,07. As in the case of the phosphogypsum analyzed in Bacau, as well as in the zones TM, VC and N, the radiometric analyzes results indicate a high content of U-232 and lower in Th-232. In conclusion, based on the analyzes carried out on samples of phosphogypsum from the four areas, and the higher U and lower Th contents, it follows that we are dealing with phosphogypsum thet results from a sedimentary type rock. Inductively coupled plasma - atomic emission spectrometry (ICP-AES) analyses performed on selected samples of phosphogypsum from the four deposits showed that the contents in the main REE (cerium, erbium, neodymium, thorium, ytterbium) are specific for the phosphogypsum issued from the processing of sedimentary raw phosphates. The results are: Turnu Magurele - Ce (ppm) - (29,1-663,1); Er (ppm) - (0,9-11,7); La (ppm) - (22,7-469,0); Nd (ppm) - (21,1-260-5); Th (ppm) - (0,3-20,8); Yb (ppm) - (1,1-6,8). Valea Calugareasca - Ce (ppm) - (30,2-454,2; Er (ppm) - (0,8-7,3); La (ppm) - (35,7-322,5); Nd (ppm) - (22,3-188,2); Th (ppm) - (0,0-12,8); Yb (ppm) - (1,6-5,0). Navodari - Ce (ppm) - (3,9-165,0); Er (ppm) - (1,8-7,7); La (ppm) - (14,5-135,6); Nd (ppm) - (3,8-90,6); Th (ppm) - (0,8-6,5); Yb (ppm) - (1,8-6,1). Bacau - Ce (ppm) - (19,3-174,8); Er (ppm) - 13,1-18,8); La (ppm) - (36,2-134,2); Nd (ppm) - (24,5-104,5); Th (ppm) (1,7-5,2); Yb (ppm) - (1,9-6,6).

A geochronologic framework for the Ziegler Reservoir fossil site, Snowmass Village, Colorado

USGS Publications Warehouse

Mahan, Shannon; Gray, Harrison J.; Pigati, Jeffrey S.; Wilson, Jim; Lifton, Nathaniel A.; Paces, James B.; Blaauw, Maarten

2014-01-01

The Ziegler Reservoir fossil site near Snowmass Village, Colorado, provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the last interglacial period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10Be and 26Al ages on a boulder on the crest of a moraine that impounded the lake suggest that the ages of the sediments that hosted the fossils are between ~ 140 ka and > 45 ka. Uranium-series ages of vertebrate remains generally fall within these bounds, but extremely low uranium concentrations and evidence of open-system behavior limit their utility. Optically stimulated luminescence (OSL) ages (n = 18) obtained from fine-grained quartz maintain stratigraphic order, were replicable, and provide reliable ages for the lake sediments. Analysis of the equivalent dose (DE) dispersion of the OSL samples showed that the sediments were fully bleached prior to deposition and low scatter suggests that eolian processes were likely the dominant transport mechanism for fine-grained sediments into the lake. The resulting ages show that the fossil-bearing sediments span the latest part of marine isotope stage (MIS) 6, all of MIS 5 and MIS 4, and the earliest part of MIS 3.

75 FR 29441 - Novaluron; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-26

... amend existing tolerances of novaluron in or on poultry, fat from 0.40 ppm to 7.0 ppm; poultry, meat from 0.03 ppm to 0.40 ppm; poultry, meat byproducts from 0.04 ppm to 0.80 ppm; hog, fat from 0.05 ppm..., Environmental Science Center, 701 Mapes Rd., Ft. Meade, MD 20755-5350; telephone number: (410) 305-2905; e-mail...

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... secondary uranium subcategory. 421.320 Section 421.320 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium... uranium (including depleted uranium) by secondary uranium facilities. ...

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... secondary uranium subcategory. 421.320 Section 421.320 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium... uranium (including depleted uranium) by secondary uranium facilities. ...

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... secondary uranium subcategory. 421.320 Section 421.320 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium... uranium (including depleted uranium) by secondary uranium facilities. ...

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... secondary uranium subcategory. 421.320 Section 421.320 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium... uranium (including depleted uranium) by secondary uranium facilities. ...

40 CFR 421.320 - Applicability: Description of the secondary uranium subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... secondary uranium subcategory. 421.320 Section 421.320 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Uranium Subcategory § 421.320 Applicability: Description of the secondary uranium... uranium (including depleted uranium) by secondary uranium facilities. ...

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.

Volatile chemicals identified in extracts from leaves of Japanese mugwort (Artemisia princeps pamp.).

PubMed

Umano, K; Hagi, Y; Nakahara, K; Shoji, A; Shibamoto, T

2000-08-01

Extracts from leaves of Japanese mugwort (Artemisia princeps Pamp.) were obtained using two methods: steam distillation under reduced pressure followed by dichloromethane extraction (DRP) and simultaneous purging and extraction (SPSE). A total of 192 volatile chemicals were identified in the extracts obtained by both methods using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). They included 47 monoterpenoids (oxygenated monoterpenes), 26 aromatic compounds, 19 aliphatic esters, 18 aliphatic alcohols, 17 monoterpenes (hydrocarbon monoterpenes), 17 sesquiterpenes (hydrocarbon sesquiterpenes), 13 sesquiterpenoids (oxygenated sesquiterpenes), 12 aliphatic aldehydes, 8 aliphatic hydrocarbons, 7 aliphatic ketones, and 9 miscellaneous compounds. The major volatile constituents of the extract by DRP were borneol (10.27 ppm), alpha-thujone (3.49 ppm), artemisia alcohol (2.17 ppm), verbenone (1.85 ppm), yomogi alcohol (1.50 ppm), and germacren-4-ol (1.43 ppm). The major volatile constituents of the extract by SPSE were 1,8-cineole (8.12 ppm), artemisia acetate (4.22 ppm), alpha-thujone (3.20 ppm), beta-caryophyllene (2.39 ppm), bornyl acetate (2.05 ppm), borneol (1.80 ppm), and trans-beta-farnesene (1. 78 ppm).

Release behavior of uranium in uranium mill tailings under environmental conditions.

PubMed

Liu, Bo; Peng, Tongjiang; Sun, Hongjuan; Yue, Huanjuan

2017-05-01

Uranium contamination is observed in sedimentary geochemical environments, but the geochemical and mineralogical processes that control uranium release from sediment are not fully appreciated. Identification of how sediments and water influence the release and migration of uranium is critical to improve the prevention of uranium contamination in soil and groundwater. To understand the process of uranium release and migration from uranium mill tailings under water chemistry conditions, uranium mill tailing samples from northwest China were investigated with batch leaching experiments. Results showed that water played an important role in uranium release from the tailing minerals. The uranium release was clearly influenced by contact time, liquid-solid ratio, particle size, and pH under water chemistry conditions. Longer contact time, higher liquid content, and extreme pH were all not conducive to the stabilization of uranium and accelerated the uranium release from the tailing mineral to the solution. The values of pH were found to significantly influence the extent and mechanisms of uranium release from minerals to water. Uranium release was monitored by a number of interactive processes, including dissolution of uranium-bearing minerals, uranium desorption from mineral surfaces, and formation of aqueous uranium complexes. Considering the impact of contact time, liquid-solid ratio, particle size, and pH on uranium release from uranium mill tailings, reducing the water content, decreasing the porosity of tailing dumps and controlling the pH of tailings were the key factors for prevention and management of environmental pollution in areas near uranium mines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermally induced distortion of a high-average-power laser system by an optical transport system

NASA Astrophysics Data System (ADS)

Chow, Robert; Ault, Linda E.; Taylor, John R.; Jedlovec, Don

1999-11-01

The atomic vapor laser isotope separation process uses high- average power lasers that have the commercial potential to enrich uranium for the electric power utilities. The transport of the laser beam through the laser system to the separation chambers requires high performance optical components, most of which have either fused silica or Zerodur as the substrate material. One of the requirements of the optical components is to preserve the wavefront quality of the laser beam that propagate over long distances. Full aperture tests with the high power process lasers and finite element analysis (FEA) have been performed on the transport optics. The wavefront distortions of the various sections of the transport path were measured with diagnostic Hartmann sensor packages. The FEA results were derived from an in-house thermal-structural- optical code which is linked to the commercially available CodeV program. In comparing the measured and predicted results, the bulk absorptance of fused silica was estimated to about 50 ppm/cm in the visible wavelength regime. Wavefront distortions will be reported on optics made from fused silica and Zerodur substrate materials.

Nuclear tracks, Sm isotopes and neutron capture effects in the Elephant Morraine shergottite

NASA Technical Reports Server (NTRS)

Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.

1986-01-01

Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine shergottite, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the shergottite parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.

Elemental analysis using natural gamma-ray spectroscopy

NASA Astrophysics Data System (ADS)

Aksoy, A.; Naqvi, A. A.; Khiari, F. Z.; Abujarad, F.; Al-Ohali, M.; Sumani, M.

1994-12-01

A gamma-ray spectroscopy setup has been recently established to measure the natural gamma-ray activity from potassium ( 40K), uranium ( 238U), and thorium ( 232Th) isotopes in rock samples of oil well-logs. The setup mainly consists of a shielded 135 cm 3 Hyper Pure Germanium (HPGe) detector, a 5 in. × 5 in. NaT(Tl) detector and a PC based data acquisition system. The core samples, with 70-100 g weight, have cylindrical geometry and are sealed such that radon gas from 238U decay would not escape from the sample. For room background subtraction, pure quartz samples identical to core samples were used. The sample is first counted with the HPGe detector to identify the elements through its characteristics gamma rays. Then the elemental concentration is determined by counting the sample with a NaI detector. In order to determine the absolute concentrations, the sample activity is compared with the activities of standards supplied by NIST and IAEA. The concentration of 238U and 232Th has been determined in ppm range with that of 40K in wt.%.

Comparison of the incipient lesion enamel fluoride uptake from various prescription and OTC fluoride toothpastes and gels.

PubMed

Schemehorn, B R; DiMarino, J C; Movahed, N

2014-01-01

The objective of this in vitro study was to compare the fluoride uptake into incipient enamel lesions of a novel 970 ppm F- ion SnF2 over-the-counter (OTC) gel (Enamelon Preventive Treatment Gel) and a novel 1150 ppm F- ion OTC toothpaste (Enamelon), each delivering amorphous calcium phosphate (ACP), to the uptake from two different prescription strength, 5000 ppm F- ion dentifrices containing tri-calcium phosphate (TCP) and a prescription 900 ppm F- ion paste containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The test procedure followed method #40 in the US-FDA Anticaries Drug Products for OTC Human Use, Final Monograph testing procedures. Eight sets of twelve incisor enamel cores were mounted in Plexiglas rods and the exposed surfaces were polished. The indigenous fluoride levels of each specimen were determined prior to treatment. The treatments were performed using slurries of a negative control (water) and the following products applied to a set of sound enamel cores: 5000 ppm F- ion, sodium fluoride (NaF) prescription (Rx) dentifrice "A" containing TCP; 5000 ppm F- ion, NaF Rx dentifrice "B" containing TCP; 900 ppm F- ion, NaF Rx paste with CPP-ACP; 1150 ppm F- ion, NaF OTC toothpaste; 1150 ppm F- ion, stannous fluoride (SnF2) OTC toothpaste delivering ACP (Enamelon); 1100 ppm F- ion, SnF2 OTC toothpaste; and 970 ppm F- ion, SnF2 OTC gel delivering ACP (Enamelon Preventive Treatment Gel). The twelve specimens of each group were immersed into 25 ml of their assigned slurry with constant stirring (350 rpm) for 30 minutes. Following treatment, one layer of enamel was removed from each specimen and analyzed for fluoride and calcium. The pre-treatment fluoride (indigenous) level of each specimen was subtracted from the post-treatment value to determine the change in enamel fluoride due to the test treatment. The increase in the average fluoride uptake for treated enamel cores was: 10,263 ± 295 ppm for the 970 ppm F- ion, Enamelon Preventive Treatment Gel; 7,016 ± 353 ppm for the 1150 ppm F- ion Enamelon Toothpaste; 4,138 ± 120 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "A" with TCP; 3801 ± 121 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "B" with TCP; 2,647 ± 57 ppm for the 1100 ppm F- ion, SnF2 OTC toothpaste; 1470 ± 40 ppm for the 1150 ppm F- ion, NaF OTC toothpaste; and 316 ± 9 ppm for the 900 ppm F- ion, NaF paste with CPP-ACP. The differences among all the products tested were statistically significant (p < 0.05), except for the two 5000 ppm F- ion products with TCP that were not statistically different from one another, and the 900 ppm F ion, NaF paste with CPP-ACP that was not statistically different from the negative water control. The Enamelon products (970 ppm and 150 ppm F ion, SnF2OTC dentifrices) delivering ACP provide statistically significantly more fluoride to incipient enamel lesions than two prescription strength 5000 ppm F- ion toothpastes containing TCP, the 900 ppm F- ion prescription paste containing CPP-ACP, and the other OTC toothpastes compared in this study.

NTP toxicology and carcinogenesis studies of chromium picolinate monohydrate (CAS No. 27882-76-4) in F344/N rats and B6C3F1 mice (feed studies).

PubMed

2010-06-01

Chromium picolinate monohydrate is the commercially available form of chromium picolinate. Chromium picolinate is one of a number of compounds that contain chromium in the trivalent state (Cr III), which is the predominant form of chromium in nature. Humans ingest Cr III in food and dietary supplements. The major uses of Cr III in the chemical and manufacturing industries include production of chromium pigments and leather tanning. Chromium picolinate was nominated by the National Cancer Institute and a private individual for testing based on the potential for widespread consumer exposure from use as a dietary supplement. Male and female F344/N rats and B6C3F1 mice were exposed to chromium picolinate monohydrate (95% to 96% pure) in feed for 3 months or 2 years. Genetic toxicology studies with chromium picolinate monohydrate were conducted in Salmonella typhimurium and mouse peripheral blood erythrocytes. Genetic toxicology studies with chromium picolinate were conducted in S. typhimurium and rat bone marrow cells. 3-MONTH STUDY IN RATS: Groups of 10 male and 10 female rats were fed diets containing 0, 80, 240, 2,000, 10,000, or 50,000 ppm chromium picolinate monohydrate (equivalent to average daily doses of approximately 7, 20, 160, 800, and 4,240 mg chromium picolinate monohydrate/kg body weight to males and 6, 20, 160, 780, and 4,250 mg/kg to females) for 14 weeks. All rats survived to the end of the study. Mean body weights and feed consumption of all exposed groups of males and females were similar to those of the control groups throughout the study. No exposure-related lesions occurred in males or females. 3-MONTH STUDY IN MICE: Groups of 10 male and 10 female mice were fed diets containing 0, 80, 240, 2,000, 10,000, or 50,000 ppm chromium picolinate monohydrate (equivalent to average daily doses of approximately 17, 50, 450, 2,300, and 11,900 mg chromium picolinate monohydrate/kg body weight to males and 14, 40, 370, 1,775, and 9,140 mg/kg to females) for 14 weeks. All mice survived to the end of the study. Mean body weights and feed consumption of all exposed groups were similar to those of the control groups throughout the study. No exposure-related lesions occurred in male or female mice. 2-YEAR STUDY IN RATS: Groups of 50 male and 50 female rats were fed diets containing 0, 2,000, 10,000, or 50,000 ppm chromium picolinate monohydrate (equivalent to average daily doses of approximately 90, 460, and 2,400 mg/kg to males and 100, 510, and 2,630 mg/kg to females) for 105 weeks. Survival of all exposed groups of males and females was similar to that of the control groups. Mean body weights and feed consumption of exposed groups of males and females were generally similar to those of the controls throughout the study. The incidence of preputial gland adenoma was significantly increased in males exposed to 10,000 ppm and exceeded the historical control ranges. 2-YEAR STUDY IN MICE: Groups of 50 male and 50 female mice were fed diets containing 0, 2,000, 10,000, or 50,000 ppm chromium picolinate monohydrate (equivalent to average daily doses of approximately 250, 1,200, and 6,565 mg/kg to males and 240, 1,200, and 6,100 mg/kg to females) for 105 weeks. Survival of all exposed groups of males and females was similar to that of the control groups. Mean body weights of exposed groups of males were generally similar to those of the controls throughout the study; mean body weights of 50,000 ppm females was 10% less than the control group at 1 year. Feed consumption by exposed groups of males and females was similar to that by the controls throughout the study. No neoplasms or nonneoplastic lesions were attributed to exposure to chromium picolinate monohydrate. In the standard screening assays conducted by the NTP, chromium picolinate monohydrate showed no clear evidence of genotoxicity. It was not mutagenic in Salmonella typhimurium strains TA98 or TA100 or Escherichia coli strain WP2 uvrA/pKM101 when tested with or without exogenous metabolic activation (S9). No increase in the frequency of micronucleated normochromatic erythrocytes was observed in male B6C3F1 mice administered chromium picolinate monohydrate in feed for 3 months. A small increase in micronucleated normochromatic erythrocytes was seen in female mice at the highest exposure concentration tested, and the results in female mice were considered equivocal. Additional genotoxicity testing was conducted with chromium picolinate (not the monohydrate form of the compound), and results were also negative. No induction of gene mutations was observed in two independent studies conducted in several strains of S. typhimurium with and without S9. No induction of micronucleated polychromatic erythrocytes was observed in bone marrow of male F344/N rats treated with chromium picolinate by oral gavage three times at 24-hour intervals. Under the conditions of these 2-year feed studies there was equivocal evidence of carcinogenic activity* of chromium picolinate monohydrate in male F344/N rats based on an increase in the incidence of preputial gland adenoma. There was no evidence of carcinogenic activity of chromium picolinate monohydrate in female F344/N rats or in male or female B6C3F1 mice.

Simulating a Dynamic Antarctic Ice Sheet in the Early to Middle Miocene

NASA Astrophysics Data System (ADS)

Gasson, E.; DeConto, R.; Pollard, D.; Levy, R. H.

2015-12-01

There are a variety of sources of geological data that suggest major variations in the volume and extent of the Antarctic ice sheet during the early to middle Miocene. Simulating such variability using coupled climate-ice sheet models is problematic due to a strong hysteresis effect caused by height-mass balance feedback and albedo feedback. This results in limited retreat of the ice sheet once it has reached the continental size, as likely occurred prior to the Miocene. Proxy records suggest a relatively narrow range of atmospheric CO2 during the early to middle Miocene, which exacerbates this problem. We use a new climate forcing which accounts for ice sheet-climate feedbacks through an asynchronous GCM-RCM coupling, which is able to better resolve the narrow Antarctic ablation zone in warm climate simulations. When combined with recently suggested mechanisms for retreat into subglacial basins due to ice shelf hydrofracture and ice cliff failure, we are able to simulate large-scale variability of the Antarctic ice sheet in the Miocene. This variability is equivalent to a seawater oxygen isotope signal of ~0.5 ‰, or a sea level equivalent change of ~35 m, for a range of atmospheric CO2 between 280 - 500 ppm.

PRODUCTION OF URANIUM METAL BY CARBON REDUCTION

DOEpatents

Holden, R.B.; Powers, R.M.; Blaber, O.J.

1959-09-22

The preparation of uranium metal by the carbon reduction of an oxide of uranium is described. In a preferred embodiment of the invention a charge composed of carbon and uranium oxide is heated to a solid mass after which it is further heated under vacuum to a temperature of about 2000 deg C to produce a fused uranium metal. Slowly ccoling the fused mass produces a dendritic structure of uranium carbide in uranium metal. Reacting the solidified charge with deionized water hydrolyzes the uranium carbide to finely divide uranium dioxide which can be separated from the coarser uranium metal by ordinary filtration methods.

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)

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)

De-contamination of pesticide residues in food by ionizing radiation

NASA Astrophysics Data System (ADS)

Basfar, Ahmed A.; Mohamed, Khaled A.; Al-Saqer, Omar A.

2012-04-01

The role of gamma irradiation on removal of pesticides in aqueous solutions or in vegetables and fruits was investigated. Radiation - induced decontamination of pesticides is generally greater in aqueous solutions than in selected vegetables and fruits. Residues of malathion (0.5 ppm in potatoes, 8 ppm in onions and dates), pirimiphos-methyl (1 ppm in onions and grapes) and cypermethrin (0.05 ppm in potatoes and 0.1 ppm in onions) were not reduced to below maximum residue limits (MRLs) for irradiation doses up to 1 kGy. The same trend was observed when irradiation was performed for grapes fortified with malathion (8 ppm) and cypermethrin (2 ppm) for absorbed doses up to 2 kGy. Ionizing radiation reduced the residues of pirimiphos-methyl (0.05 ppm in potatoes at1 kGy, 1 ppm in grapes at 2 kGy and 0.1 ppm in dates at1 kGy), malathion (8 ppm in grapes at 7 kGy) and cypermethrin (2 ppm in grapes at 7 kGy) to below maximum residue limits (MRLs).

Influence of glyphosate in planktonic and biofilm growth of Pseudomonas aeruginosa

PubMed Central

Lima, Ilana Schneider; Baumeier, Nicole Carmo; Rosa, Rosimeire Takaki; Campelo, Patrícia Maria Stuelp; Rosa, Edvaldo Antonio Ribeiro

2014-01-01

This study evaluated the impact of different concentrations of glyphosate (Rondup®) on planktonic and biofilm growth of P. aeruginosa. Aerobic and anaerobic cultures of P. aeruginosa ATCC®15442 inoculated in MHB + glyphosate (0.845 ppm, 1.690 ppm, 8.45 ppm, 16.90 ppm, 84.50 ppm, 169 ppm, 845 ppm, and 1690 ppm) and cultured in normoxia and anoxia, following their OD560nm every hour for 24 h. Biofilms of adapted cells were formed in the presence of glyphosate (0.845 to 1690 ppm) in normoxia and anoxia for 36 h. Glyphosate at concentrations higher than 84.5 ppm reduces the cell density of planktonic aerobic cultures (p < 0.05). However, these same concentrations favor the planktonic anaerobic growth (p < 0.05). On the other hand, the herbicide favors a slight growth of biofilms in a concentration-dependent manner up to 84.5 ppm (p > 0.05), and more pronounced over 169 ppm. Anaerobic biofilms have their growth more readily favored (p < 0.05), regardless of concentration. In a concentration-dependent manner, glyphosate interferes with the growth ability of P. aeruginosa ATCC®15442. PMID:25477933

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 embedded shrapnel.

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. The...

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. The...

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. The...

Anomalous metal concentrations in soil and till at the Ballinalack Zn-Pb deposit, Ireland

NASA Astrophysics Data System (ADS)

Kalveram, Ann-Kristin; McClenaghan, Seán H.; Kamber, Balz S.

2017-04-01

Metals such as zinc, iron, arsenic and lead are commonly found in low concentrations within soils. These signatures may occur as a result of natural dispersion from metal-bearing geological formations and (or) from anthropogenic sources. Prior to investigating any high or anomalous concentrations of metals in the surficial environment, it is important to reconcile potential sources of metals and verify whether element anomalies are in response to buried mineralization. Here we show how to distinguish true elevated concentrations from naturally occurring variations within a soil system. The research area is situated above the limestone-hosted Ballinalack Zn-Pb deposit in the central Irish Midlands. To investigate the pedogenesis and its related geochemical signature, top of the till and the BC soil horizon were sampled. Although the area can be described as pasture land, it does not preclude previous anthropogenic influences from former agricultural use and local small scale peat harvesting. For the soil BC horizon as well as in the top of the till, aqua regia-digestible element concentrations vary significantly and locally reach anomalous levels: Zn (median: 104 ppm; range: 27 - 13150 ppm), Pb (median: 16 ppm; range: 2 - 6430 ppm), As (median: 7.7 ppm; range: 1.4 - 362 ppm), Ag (median: 0.12 ppm; range: 0.04 - 19.9 ppm), Ba (median: 40 ppm; range: 10 - 1230 ppm), Cd (median: 1.5 ppm; range: 0.2 - 68 ppm), Co (median: 7.3 ppm; range: 0.5 - 22 ppm), Ni (median: 37 ppm; range: 3 - 134 ppm), Fe (median: 17900 ppm; range: 5000 - 52300 ppm), Ga (median: 2.4 ppm; range: 0.3 - 7.6 ppm), Sb (median: 1.2 ppm; range: 0.1 - 197 ppm) and Tl (median: 0.3 ppm; range: 0.02 - 8.6 ppm). Comparison with background levels from the area and grouped according to underlying geology, enrichment factor calculations (against Nb and Zr) indicate an elemental response to metalliferous-bearing bedrock. These results confirm that soil anomalies of Zn, Pb, As, Ag, Ba, Cd, Ni, Sb and Tl, are consistent with the characteristics of buried Waulsortian-hosted sulphide mineralization; furthermore, Mo, Se, Sn and V are anomalous. Principal component analysis reveals a strong geochemical relationship between Ag, As, Ba, Cd, Pb, Sb, Tl and Zn in soils, representing metal dispersion from a shallow sulphide lens underneath till and soil horizons. Results of laser ablation ICP-MS analyses of pyrite and sphalerite from the Ballinalack deposit confirm this geochemical relationship. These outcomes have helped to distinguish between true geological anomalies and possible anthropogenic inputs, an important consideration for any mineral exploration activities on cultivated land.

Clay minerals trap hydrogen in the Earth's crust: Evidence from the Cigar Lake uranium deposit, Athabasca

NASA Astrophysics Data System (ADS)

Truche, Laurent; Joubert, Gilles; Dargent, Maxime; Martz, Pierre; Cathelineau, Michel; Rigaudier, Thomas; Quirt, David

2018-07-01

Hydrogen (H2)-rich fluids are observed in a wide variety of geologic settings including gas seeps in serpentinized ultramafic rocks, sub-seafloor hydrothermal vents, fracture networks in crystalline rocks from continental and oceanic crust, and volcanic gases. Natural hydrogen sources can sustain deep microbial ecosystems, induce abiotic hydrocarbons synthesis and trigger the formation of prebiotic organic compounds. However, due to its extreme mobility and small size, hydrogen is not easily trapped in the crust. If not rapidly consumed by redox reactions mediated by bacteria or suitable mineral catalysts it diffuses through the rocks and migrates toward the surface. Therefore, H2 is not supposed to accumulate in the crust. We challenge this view by demonstrating that significant amount of H2 may be adsorbed by clay minerals and remain trapped beneath the surface. Here, we report for the first time H2 content in clay-rich rocks, mainly composed of illite, chlorite, and kaolinite from the Cigar Lake uranium ore deposit (northern Saskatchewan, Canada). Thermal desorption measurements reveal that H2 is enriched up to 500 ppm (i.e. 0.25 mol kg-1 of rock) in these water-saturated rocks having a very low total organic content (<0.5 wt%). Such hydrogen uptake is comparable and even exceeds adsorbed methane capacities reported elsewhere for pure clay minerals or shales. Sudoite (Al-Mg di-trioctahedral chlorite) is probably the main mineral responsible for H2 adsorption in the present case. The presence of multiple binding sites in interlinked nanopores between crystal layers of illite-chlorite particles offers the ideal conditions for hydrogen sorption. We demonstrate that 4 to 17% of H2 produced by water radiolysis over the 1.4-Ga-lifetime of the Cigar Lake uranium ore deposit has been trapped in the surrounding clay alteration haloes. As a result, sorption processes on layered silicates must not be overlooked as they may exert an important control on the fate and mobility of H2 in the crust. Furthermore, the high capacity of clay minerals to sorb molecular hydrogen may also open up new opportunities for exploration of unexpected energy resources and for H2 storage based on geo-inspired materials.

Millennial Variability of Eastern Equatorial Bottom Water Oxygenation and Atmospheric CO2 over the past 100 kyr

NASA Astrophysics Data System (ADS)

Marcantonio, F.; Loveley, M.; Wisler, M.; Hostak, R.; Hertzberg, J. E.; Schmidt, M. W.; Lyle, M. W.

2017-12-01

Storage of respired carbon in the deep ocean may play a significant role in lowering atmospheric CO2 concentrations by about 80 ppm during the last glacial maximum compared to pre-industrial times. The cause of this sequestration and the subsequent release of the deep respired carbon pool at the last termination remains elusive. Within the last glacial period, on millennial timescales, the relationship between the CO2 cycle and any waxing and waning of a deep respired pool also remains unclear. To further our understanding of the millennial variability in the storage of a deep-ocean respired carbon pool during the last glacial, we measure authigenic uranium and 230Th-derived non-lithogenic barium fluxes (xsBa flux) in two high-sedimentation-rate cores from the Panama Basin of the Eastern Equatorial Pacific (EEP) (8JC, 6° 14.0' N, 86° 02.6' W; 1993 m water depth; 17JC 00° 10.8' S, 85° 52.0' W; 2846 m water depth). Sediment authigenic U concentrations are controlled by the redox state of sediments which, in turn, is a function of the rain of organic material from the surface ocean and the oxygen content of bottom waters. At both 8JC and 17JC, the mismatch between xsBa fluxes, a proxy for the reconstruction of oceanic productivity, and authigenic uranium concentrations suggests that the primary control of the latter values is changes in bottom water oxygenation. Peak authigenic uranium concentrations occur during glacial periods MIS 2, 3, and 4, respectively, and are two to three times higher than those during interglacial periods, MIS 1 and 5. EEP bottom waters were likely suboxic during times of the last glacial period when atmospheric CO2 concentrations were at their lowest concentrations. In addition, the pattern of increased deep-water oxygenation during times of higher CO2 during the last glacial is similar to that reported in a study of authigenic U in sediments from the Antarctic Zone of the Southern Ocean (Jaccard et al., 2016). We suggest that a respired carbon pool existed within a large swath of the abyssal Southern and Pacific Oceans throughout the entire last glacial cycle, and that this respired carbon was periodically released through increased ventilation of deep ocean waters. Jaccard et al. (2016) Nature 530, 207-210.

75 FR 17573 - Nicosulfuron; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

..., meat byproducts; goat, fat; goat, meat; goat, meat byproducts; grass, forage; grass, hay; horse, fat... grass, forage at 9.0 parts per million (ppm); grass, hay at 25.0 ppm; fat (of cattle, goat, hog, horse... at 0.05 ppm; goat, fat at 0.01 ppm; goat, meat at 0.01 ppm; goat, meat byproducts at 0.05 ppm; grass...

76 FR 31485 - Bromoxynil; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-01

... million (ppm) to 0.2 ppm; grass, hay from 3.0 ppm to 5.0 ppm; and grass, forage from 3.0 ppm to 18 ppm... increased as a result of the proposed changes to the use patterns for sorghum and grasses. The reasons for... Assessment for Amended Uses on Grass Grown for Seed, Conservation Reserve Program Areas, and Grain Sorghum...

Toxicology of oxides of nitrogen. I. Toxic concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

La Towsky, L.W.; MacQuiddy, E.L.; Tollman, J.P.

1941-01-01

One hundred twelve rabbits, cats, guinea pigs, rats, and mice were exposed to 30 to 1000 ppM NO/sub 2/. Average time to produce death was: 30 ppM - none in 3 hr, 100 ppM - 318 min, 150 ppM - 90 min, 400 ppM - 58 min, 600 ppM - 32 min, 800 ppM - 29 min, 1000 ppM - 19 min. Rats and mice were more sensitive, sometimes exhibiting delayed effects (e.g., 2 to 3 hr at 55 ppM). Cats were most sensitive in that they thrash excitedly, thus breathing more. Methemoglobin was frequently seen in blood during exposure.more » Death was from edema (most common), asphyxia, or pneumonitis (secondary).« less

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.

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.

Decontamination of uranium-contaminated waste oil using supercritical fluid and nitric acid.

PubMed

Sung, Jinhyun; Kim, Jungsoo; Lee, Youngbae; Seol, Jeunggun; Ryu, Jaebong; Park, Kwangheon

2011-07-01

The waste oil used in nuclear fuel processing is contaminated with uranium because of its contact with materials or environments containing uranium. Under current law, waste oil that has been contaminated with uranium is very difficult to dispose of at a radioactive waste disposal site. To dispose of the uranium-contaminated waste oil, the uranium was separated from the contaminated waste oil. Supercritical R-22 is an excellent solvent for extracting clean oil from uranium-contaminated waste oil. The critical temperature of R-22 is 96.15 °C and the critical pressure is 49.9 bar. In this study, a process to remove uranium from the uranium-contaminated waste oil using supercritical R-22 was developed. The waste oil has a small amount of additives containing N, S or P, such as amines, dithiocarbamates and dialkyldithiophosphates. It seems that these organic additives form uranium-combined compounds. For this reason, dissolution of uranium from the uranium-combined compounds using nitric acid was needed. The efficiency of the removal of uranium from the uranium-contaminated waste oil using supercritical R-22 extraction and nitric acid treatment was determined.

Analyzing the impact of reactive transport on the repository performance of TRISO fuel

NASA Astrophysics Data System (ADS)

Schmidt, Gregory

One of the largest determiners of the amount of electricity generated by current nuclear reactors is the efficiency of the thermodynamic cycle used for power generation. Current light water reactors (LWR) have an efficiency of 35% or less for the conversion of heat energy generated by the reactor to electrical energy. If this efficiency could be improved, more power could be generated from equivalent volumes of nuclear fuel. One method of improving this efficiency is to use a coolant flow that operates at a much higher temperature for electricity production. A reactor design that is currently proposed to take advantage of this efficiency is a graphite-moderated, helium-cooled reactor known as a High Temperature Gas Reactor (HTGR). There are significant differences between current LWR's and the proposed HTGR's but most especially in the composition of the nuclear fuel. For LWR's, the fuel elements consist of pellets of uranium dioxide or plutonium dioxide that are placed in long tubes made of zirconium metal alloys. For HTGR's, the fuel, known as TRISO (TRIstructural-ISOtropic) fuel, consists of an inner sphere of fissile material, a layer of dense pyrolytic carbon (PyC), a ceramic layer of silicon carbide (SiC) and a final dense outer layer of PyC. These TRISO particles are then compacted with graphite into fuel rods that are then placed in channels in graphite blocks. The blocks are then arranged in an annular fashion to form a reactor core. However, this new fuel form has unanswered questions on the environmental post-burn-up behavior. The key question for current once-through fuel operations is how these large irradiated graphite blocks with spent fuel inside will behave in a repository environment. Data in the literature to answer this question is lacking, but nevertheless this is an important question that must be answered before wide-spread adoption of HTGR's could be considered. This research has focused on answering the question of how the large quantity of graphite surrounding the spent HTGR fuel will impact the release of aqueous uranium from the TRISO fuel. In order to answer this question, the sorption and partitioning behavior of uranium to graphite under a variety of conditions was investigated. Key systematic variables that were analyzed include solution pH, dissolved carbonate concentration, uranium metal concentration and ionic strength. The kinetics and desorption characteristics of uranium/graphite partitioning were studied as well. The graphite used in these experiments was also characterized by a variety of techniques and conclusions are drawn about the relevant surface chemistry of graphite. This data was then used to generate a model for the reactive transport of uranium in a graphite matrix. This model was implemented with the software code CXTFIT and validated through the use of column studies mirroring the predicted system.

Effects of dietary hexachlorobenzene exposure on regional brain biogenic amine concentrations in mink and European ferrets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bleavins, M.R.; Bursian, S.J.; Brewster, J.S.

1984-01-01

In the initial trial, adult mink and ferrets were administered hexachlorobenzene (HCB) via the feed at concentrations of 1, 5, or 25 ppm for 47 wk. Animals receiving 125 and 625 ppm HCB in the diet died before termination of the experiment, with female ferrets at the 125 ppm level displaying abnormal aggressiveness and hyperexcitability just prior to death. Hypothalamic serotonin (5-HT) was significantly elevated at all dose levels in mink, and cerebellar 5-HT was significantly elevated at 1 ppm in the ferret. Regional brain biogenic amine concentrations were also determined in the offspring of the female mink that weremore » administered 1 and 5 ppm HCB. Hypothalamic dopamine (DA) concentrations were significantly depressed by 1 and 5 ppm in these kits. In a second study, adult male and female ferrets were administered 250 or 500 ppm HCB via the diet for 7 wk. Two animals at the 250-ppm level and 3 animals at the 500-ppm level died before termination of the experiment without showing behavioral changes. Of the remaining animals, 3 ferrets at 250 ppm and 1 ferret at 500 ppm showed slight aggressiveness and hyperexcitability during the last week of the experiment. Concentrations of 5-HT were significantly elevated at 500 ppm in the cerebral hemispheres and at 250 ppm in the midbrain of male ferrets, while in the females, 5-HT was elevated in the cerebral hemispheres at 250 ppm and in the hypothalamus at both 250 and 500 ppm. Norepinephrine (NE) concentrations were significantly elevated in the cerebellum of males exposed to 250 and 500 ppm, as were NE concentrations in the midbrain. HCB at 500 ppm caused a significant increase in medullary NE, while 250 ppm caused an increase in hypothalamic NE in males. The only change in regional brain dopamine (DA) concentrations occurred at 500 ppm HCB in the midbrain of males, where there was a significant elevation of this neurotransmitter. 34 references, 7 tables.« less

Worker exposure to methanol vapors during cleaning of semiconductor wafers in a manufacturing setting.

PubMed

Gaffney, Shannon; Moody, Emily; McKinley, Meg; Knutsen, Jeffrey; Madl, Amy; Paustenbach, Dennis

2008-05-01

An exposure simulation was conducted to characterize methanol exposure of workers who cleaned wafers in quality control departments within the semiconductor industry. Short-term (15 min) and long-term (2-4 hr) personal and area samples (at distances of 1 m and 3-6 m from the source) were collected during the 2-day simulation. On the first day, 45 mL of methanol were used per hour by a single worker washing wafers in a 102 m(3) room with a ventilation rate of about 10 air changes per hour (ACH). Virtually all methanol volatilized. To assess exposures under conditions associated with higher productivity, on the second day, two workers cleaned wafers simultaneously, together using methanol at over twice the rate of the first day (95 mL/hr). On this day, the ventilation rate was halved (5 ACH). Personal concentrations on the first day averaged 60 ppm (SD = 46 ppm) and ranged from 10-140 ppm. On the second day, personal concentrations for both workers averaged 118 ppm (SD = 50 ppm; range: 64-270 ppm). Area concentrations measured on the first day at 1 m from the source and throughout the balance of the room averaged 29 ppm (SD = 19 ppm; range: 4-83 ppm) and 18 ppm (SD = 12 ppm; range: 3-42 ppm), respectively. As expected, area concentrations measured on the second day were higher than the first and averaged 73 ppm (SD = 25 ppm; range: 27-140 ppm) at 1 meter and 48 ppm (SD = 13 ppm; range: 21-67 ppm) throughout the balance of the room. The results of this simulation suggest that the use of methanol to clean semiconductor wafers without the use of local exhaust ventilation and with relatively low room ventilation rates is unlikely to result in worker exposures exceeding the current ACGIH(R) threshold limit value of 200 ppm. This study also confirmed prior studies suggesting that when a relatively volatile chemical is located within arm's length (near field), breathing zone concentrations will be about two- to threefold greater than the room concentration when the air exchange rate is 5-10 ACH.

Diffusive gradient in thin FILMS (DGT) compared with soil solution and labile uranium fraction for predicting uranium bioavailability to ryegrass.

PubMed

Duquène, L; Vandenhove, H; Tack, F; Van Hees, M; Wannijn, J

2010-02-01

The usefulness of uranium concentration in soil solution or recovered by selective extraction as unequivocal bioavailability indices for uranium uptake by plants is still unclear. The aim of the present study was to test if the uranium concentration measured by the diffusive gradient in thin films (DGT) technique is a relevant substitute for plant uranium availability in comparison to uranium concentration in the soil solution or uranium recovered by ammonium acetate. Ryegrass (Lolium perenne L. var. Melvina) is grown in greenhouse on a range of uranium spiked soils. The DGT-recovered uranium concentration (C(DGT)) was correlated with uranium concentration in the soil solution or with uranium recovered by ammonium acetate extraction. Plant uptake was better predicted by the summed soil solution concentrations of UO(2)(2+), uranyl carbonate complexes and UO(2)PO(4)(-). The DGT technique did not provide significant advantages over conventional methods to predict uranium uptake by plants. Copyright 2009 Elsevier Ltd. All rights reserved.

Calibration of equipment for analysis of drinking water fluoride: a comparison study.

PubMed

Quock, Ryan L; Chan, Jarvis T

2012-03-01

Current American Dental Association evidence-based recommendations for prescription of dietary fluoride supplements are based in part on the fluoride concentration of a pediatric patient's drinking water. With these recommendations in mind, this study compared the relative accuracy of fluoride concentration analysis when a common apparatus is calibrated with different combinations of standard values. Fluoride solutions in increments of 0.1 ppm, from a range of 0.1 to 1.0 ppm fluoride, as well as 2.0 and 4.0 ppm, were gravimetrically prepared and fluoride concentration measured in pentad, using a fluoride ion-specific electrode and millivolt meter. Fluoride concentrations of these solutions were recorded after calibration with the following 3 different combinations of standard fluoride solutions: 0.1 ppm and 0.5 ppm, 0.1 ppm and 1.0 ppm, 0.5 ppm and 1.0 ppm. Statistical analysis showed significant differences in the fluoride content of water samples obtained with different two-standard fluoride solutions. Among the two-standard fluoride solutions tested, using 0.5 ppm and 1.0 ppm as two-standard fluoride solutions provided the most accurate fluoride measurement of water samples containing fluoride in the range of 0.1 ppm to 4.0 ppm. This information should be valuable to dental clinics or laboratories in fluoride analysis of drinking water samples.

Tumors and proliferative lesions in adult offspring after maternal exposure to methylarsonous acid during gestation in CD1 mice.

PubMed

Tokar, Erik J; Diwan, Bhalchandra A; Thomas, David J; Waalkes, Michael P

2012-06-01

Developmental exposure to inorganic arsenic is carcinogenic in humans and mice, and adult offspring of mice exposed to inorganic arsenic can develop tumors of the lung, liver, adrenal, uterus, and ovary. It has been suggested that methylarsonous acid (MMA3+), a product of the biological methylation of inorganic arsenic, could be a key carcinogenic species. Thus, pregnant CD1 mice were provided drinking water containing MMA3+ at 0 (control), 12.5, or 25 parts per million (ppm) from gestational days 8 to 18. Tumors were assessed in groups of male or female (initial n = 25) offspring up to 2 years of age. In utero treatment had no effect on survival or body weights. Female offspring exhibited increases in total epithelial uterine tumors (control 0%; 12.5 ppm 26%; 25 ppm 30%), oviduct hyperplasia (control 4%; 12.5 ppm 35%; 25 ppm 43%), adrenal cortical adenoma at 25 ppm (control 0%; 12.5 ppm 9%; 25 ppm 26%), and total epithelial ovarian tumors (control 0%; 12.5 ppm 39%; 25 ppm 26%). Male offspring showed dose-related increases in hepatocellular carcinoma (control 0%; 12.5 ppm 12%; 25 ppm 22%), adrenal adenoma (control 0%; 12.5 ppm 28%; 25 ppm 17%), and lung adenocarcinoma (control 17%; 12.5 ppm 44%). Male offspring had unusual testicular lesions, including two rete testis carcinomas, two adenomas, and three interstitial cell tumors. Overall, maternal consumption of MMA3+ during pregnancy in CD1 mice produced some similar proliferative lesions as gestationally applied inorganic arsenic in the offspring during adulthood.

Tumors and Proliferative Lesions in Adult Offspring After Maternal Exposure to Methylarsonous Acid During Gestation in CD1 Mice

PubMed Central

Tokar, Erik J.; Diwan, Bhalchandra A.; Thomas, David J.; Waalkes, Michael P.

2012-01-01

Developmental exposure to inorganic arsenic is carcinogenic in humans and mice, and adult offspring of mice exposed to inorganic arsenic can develop tumors of the lung, liver, adrenal, uterus, and ovary. It has been suggested that methylarsonous acid (MMA3+), a product of the biological methylation of inorganic arsenic, could be a key carcinogenic species. Thus, pregnant CD1 mice were provided drinking water containing MMA3+ at 0 (control), 12.5 or 25 parts per million (ppm) from gestational day 8 to 18. Tumors were assessed in groups of male or female (initial n = 25) offspring up to two years of age. In utero treatment had no effect on survival or body weights. Female offspring exhibited increases in total epithelial uterine tumors (control 0%; 12.5 ppm 26%; 25 ppm 30%), oviduct hyperplasia (control 4%; 12.5 ppm 35%; 25 ppm 43%), adrenal cortical adenoma at 25 ppm (control 0%; 12.5 ppm 9%; 25 ppm 26%), and total epithelial ovarian tumors (control 0%; 12.5 ppm 39%; 25 ppm 26%). Male offspring showed dose-related increases in hepatocellular carcinoma (control 0%; 12.5 ppm 12%; 25 ppm 22%), adrenal adenoma (control 0%; 12.5 ppm 28%; 25 ppm 17%), and lung adenocarcinoma (control 17%; 12.5 ppm 44%). Male offspring had unusual testicular lesions, including two rete testis carcinomas and two adenomas, and three interstitial cell tumors. Overall, maternal consumption of MMA3+ during pregnancy in CD1 mice produced some similar proliferative lesions as gestationally applied inorganic arsenic in the offspring during adulthood. PMID:22398986

Detection of low level benzene exposure in supermarket wrappers by urinary muconic acid.

PubMed

E S Johnson S Halabi G Netto G Lucier W Bechtold R Henderson

1999-01-01

Women who use the 'hot wire' and 'cool rod' machines to wrap meat in supermarkets are potentially exposed to low levels of benzene and polycyclic aromatic hydrocarbons present in fumes emitted during the thermal decomposition of the plastic used to wrap meat. In order to evaluate whether the benzene metabolite trans, trans-muconic acid (MA) can be used to monitor these low levels, we collected urine samples from supermarket workers, and assayed the urine for MA. Geometric mean after-shift MA levels were highest for subjects who used the 'hot wire' machine, i.e. > 300 ng mg-1 creatinine (Cr). The corresponding levels for subjects who used the 'cool rod' machine were similar to those for subjects who did not use either type of machine, and were much lower. These results indicate that urinary muconic acid has some potential for use in monitoring benzene exposures of less than 1 part per million (ppm). The study detected very high background MA levels (exceeding 2000 ng mg-1 Cr) in some subjects, suggesting that individuals in the general population without occupational exposure to benzene may have urinary MA levels equivalent to exposure to up to 2 ppm benzene in ambient air. However, since non-benzene sources of the metabolite cannot be completely ruled out as partially responsible for these high levels, the public health significance of this finding is not known at the moment.

Characterization of the phosphatic mineral of the barnacle Ibla cumingi at atomic level by solid-state nuclear magnetic resonance: comparison with other phosphatic biominerals

PubMed Central

Reid, David G.; Mason, Matthew J.; Chan, Benny K. K.; Duer, Melinda J.

2012-01-01

Ibliform barnacles are among the few invertebrate animals harnessing calcium phosphate to construct hard tissue. The 31P solid-state NMR (SSNMR) signal from the shell plates of Ibla cumingi (Iblidae) is broader than that of bone, and shifted by ca 1 ppm to low frequency. 1H–31P heteronuclear correlation (HETCOR) experiments show a continuum of different phosphorus/phosphate atomic environments, close to hydrogen populations with resonance frequencies between ca 10 and 20 ppm. Associated 1H and 31P chemical shifts argue the coexistence of weakly (high 31P frequency, low 1H frequency) to more strongly (lower 31P frequency, higher 1H frequency) hydrogen-bonded hydrogen phosphate-like molecular/ionic species. There is no resolved signal from discrete OH− ions. 13C SSNMR shows chitin, protein and other organic biomolecules but, unlike bone, there are no significant atomic scale organic matrix–mineral contacts. The poorly ordered hydrogen phosphate-like iblid mineral is strikingly different, structurally and compositionally, from both vertebrate bone mineral and the more crystalline fluoroapatite of the linguliform brachiopods. It probably represents a previously poorly characterized calcium phosphate biomineral, the evolution of which may have reflected either the chemical conditions of ancestral seas or the mechanical advantages of phosphatic biomineralization over a calcium carbonate equivalent. PMID:22298816

Developmental toxicity evaluation of unleaded gasoline vapor in the rat.

PubMed

Roberts, L; White, R; Bui, Q; Daughtrey, W; Koschier, F; Rodney, S; Schreiner, C; Steup, D; Breglia, R; Rhoden, R; Schroeder, R; Newton, P

2001-01-01

To evaluate the potential of unleaded gasoline vapor for developmental toxicity, a sample was prepared by slowly heating API 94-02 (1990 industry average gasoline) and condensing the vapor. The composition of this vapor condensate, which comprises 10.4% by volume of the starting gasoline, is representative of real-world exposure to gasoline vapor encountered at service stations and other occupational settings and consists primarily of volatile short chain (C4-C6) aliphatic hydrocarbons (i.e. paraffins) with small amounts of cycloparaffins and aromatic hydrocarbons. A preliminary study in rats and mice resulted in no developmental toxicity in either species. However, a slight reduction in maternal body weight gain in rats led to the selection of rats for this guideline study. Groups of pregnant rats (n = 24/group) were exposed to unleaded gasoline vapor at concentrations of 0, 1000, 3000, or 9000 (75% lower explosive limit) ppm equivalent to 0, 2653, 7960, or 23,900 mg/m3, for 6 h/day on gestation days 6-19. All rats were sacrificed on gestation day 20. No maternal toxicity was observed. Developmentally, there were no differences between treated and control groups in malformations, total variations, resorptions, fetal body weight, or viability. The maternal and developmental NOAEL is 9000 ppm. Under conditions of this study, unleaded gasoline vapors did not produce evidence of developmental toxicity.

Toxicologic evaluation of DHA-rich algal oil: Genotoxicity, acute and subchronic toxicity in rats.

PubMed

Schmitt, D; Tran, N; Peach, J; Bauter, M; Marone, P

2012-10-01

DHA-rich algal oil ONC-T18, tested in a battery of in vitro and in vivo genotoxicity tests, did not show mutagenic or genotoxic potential. The acute oral LD50 in rats has been estimated to be greater than 5000 mg/kg of body weight. In a 90-day subchronic dietary study, administration of DHA-rich algal oil at concentrations of 0, 10,000, 25,000, and 50,000 ppm in the diet for 13 weeks did not produce any significant toxicologic manifestations. The algal oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The no observed adverse effect level (NOAEL) was the highest level fed of 50,000 ppm which is equivalent to 3,305 and 3,679 mg/kg bw/day, for male and female rats, respectively. The studies were conducted as part of an investigation to examine the safety of DHA-rich algal oil. The results confirm that it possesses a toxicity profile similar to other currently marketed algal oils and support the safety of DHA-rich algal oil for its proposed use in food. Copyright © 2012 Elsevier Ltd. All rights reserved.

Integrated waste management as a climate change stabilization wedge.

PubMed

Bahor, Brian; Van Brunt, Michael; Stovall, Jeff; Blue, Katherine

2009-11-01

Anthropogenic sources of greenhouse gas emissions are known to contribute to global increases in greenhouse gas concentrations and are widely believed to contribute to climate change. A reference carbon dioxide concentration of 383 ppm for 2007 is projected to increase to a nominal 500 ppm in less than 50 years according to business as usual models. This concentration change is equivalent to an increase of 7 billion tonnes of carbon per year (7 Gt C year(-1)). The concept of a stabilization wedge was introduced by Pacala and Socolow (Science, 305, 968-972, 2004) to break the 7 Gt C year(- 1) into more manageable 1 Gt C year(- 1) reductions that would be achievable with current technology. A total of fifteen possible 'wedges' were identified; however, an integrated municipal solid waste (MSW) management system based on the European Union's waste management hierarchy was not evaluated as a wedge. This analysis demonstrates that if the tonnage of MSW is allocated to recycling, waste to energy and landfilling in descending order in lieu of existing 'business-as-usual' practices with each option using modern technology and best practices, the system would reduce greenhouse gas emissions by more than 1 Gt C year( -1). This integrated waste management system reduces CO(2) by displacing fossil electrical generation and avoiding manufacturing energy consumption and methane emissions from landfills.

Detection of trace nitric oxide concentrations using 1-D laser-induced fluorescence imaging

NASA Astrophysics Data System (ADS)

Yoo, J.; Lee, T.; Jeffries, J. B.; Hanson, R. K.

2008-06-01

Spectrally resolved laser-induced fluorescence (LIF) with one-dimensional spatial imaging was investigated as a technique for detection of trace concentrations of nitric oxide (NO) in high-pressure flames. Experiments were performed in the burnt gases of premixed methane/argon/oxygen flames with seeded NO (15 to 50 ppm), pressures of 10 to 60 bar, and an equivalence ratio of 0.9. LIF signals were dispersed with a spectrometer and recorded on a 2-D intensified CCD array yielding both spectral resolution and 1-D spatial resolution. This method allows isolation of NO-LIF from interference signals due to alternative species (mainly hot O2 and CO2) while providing spatial resolution along the line of the excitation laser. A fast data analysis strategy was developed to enable pulse-by-pulse NO concentration measurements from these images. Statistical analyses as a function of laser energy of these single-shot data were used to determine the detection limits for NO concentration as well as the measurement precision. Extrapolating these results to pulse energies of ˜ 16 mJ/pulse yielded a predicted detection limit of ˜ 10 ppm for pressures up to 60 bar. Quantitative 1-D LIF measurements were performed in CH4/air flames to validate capability for detection of nascent NO in flames at 10-60 bar.

Health assessment for Louisiana Army Ammunition Plant, Shreveport, Webster County, Louisiana, Region 6. CERCLIS No. LA0213820533. Preliminary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-04-10

The Louisiana Army Ammunition Plant (LAAP) is listed on the National Priorities List. The site is a 15,000-acre Federal facility located in Shreveport (Webster Parish), Louisiana. On-site ground water beneath 16 unlined surface impoundments near the southern boundary is contaminated. Access to LAAP is restricted and under 24-hour security. Contaminants include 2,4,6-trinitrotoluene (TNT), cyclonite (RDX), trinitrobenzene (TNB), and homocyclonite (HMX). Preliminary on-site sampling results have identified TNT (493,133 ppm in sediment/subsoil, 483,556 ppm in sludge, 1,033 ppm in surface soil, 7 ppm in surface water, and 18 ppm in ground water), RDX (60,224 ppm in sediment/subsoil, 602 ppm in surfacemore » soil, 60,224 ppm in sludge, and 14 ppm in ground water), TNB (2 ppm in surface water and 8 ppm in ground water), and HMX (4 ppm in ground water). Based on available information, the site is considered to be of potential public health concern because of the risk to human health caused by the possibility of human exposure to hazardous substances.« less

Growth of vegetative explant Moringa oleifera on different composition of auxin and cytokinin and its synthetic seed germination

NASA Astrophysics Data System (ADS)

Muslihatin, Wirdhatul; Jadid, Nurul; Puspitasari, Ika D.; Safitri, Chusnul E.

2017-06-01

The spread of Moringa oleifera is also rare for seed germination and viability or survival are low, and the lack of vegetative propagation method. The purpose of this study are to determine the effect of auxin and cytokinin on growth vegetative explants Moringa oleifera and its synthetic seed germination. The explants grown on MS medium with sucrose content of 30% and a range of additional hormone. Addition concentration and different types of hormone made in order to know the sensitivity and response explant growth on a variety of media to get a good callus and embryosomatic. The composition of the hormone given is MS + 2.4 D 3 ppm; MS + 2,4D 2 ppm + BAP 2 ppm; MS + NAA + 0.5 ppm kinetin 1 ppm; MS + NAA 1 ppm + kinetin 1 ppm; MS + NAA 1 ppm + 0.5 ppm kinetin. The explants were incubated at a temperature of 18-20 ° C with a photoperiod 16/8. Explants and MS medium is incubated to form embryonic callus. Seeds synthetic made from embryonic callus growing on medium 1 ppm kinetin + NAA 1 ppm with encapsulation method with sodium alginate 2%. Seed synthetic germinated in some kind of medium that medium ms0 solid (M1), ms0 liquid (M2), MS0 semi-solid (M3), MS solid NAA 1ppm + Kinetin 1 ppm (M4), MS liquid NAA 1 ppm + kinetin (M5), and semi-solid MS + NAA 1 ppm kinetin 1 ppm (M6). Synthetic seed viability was observed with the parameters of the fresh weight of synthetic seed, germination percentage and seedling. Chlorophyll content was measured by spectrophotometric method with solvent asseton. Best callus generated in this study are embryonic callus that grew on media NAA 1 ppm + kinetin 1 ppm. Embryonic callus on M6 + NAA 1 ppm kinetin 1 ppm capable of germination with an average weight of callus and sprouts of 40.38 mg. Of the entire amount of a synthetic seed on M6, just 5 seed germinate, so the percentage of germination of seeds is equal to 41.67%. with an average length of sprouts 1 cm with an average total chlorophyll content of 8.66 mg / g.

A dietary supplement for female sexual dysfunction, Avlimil, stimulates the growth of estrogen-dependent breast tumors (MCF-7) implanted in ovariectomized athymic nude mice.

PubMed

Ju, Young H; Doerge, Daniel R; Helferich, William G

2008-01-01

Avlimil, a dietary supplement advertised to ameliorate female sexual dysfunction, is a mixture of eleven herbal components, and some herbal constituents of Avlimil (including black cohosh, licorice, red raspberry, red clover and kudzu) contain phenolic compounds, which are suggested to have estrogenic, anti-estrogenic, or androgenic potential for relieving menopausal symptoms. We hypothesize that Avlimil could modulate the growth of estrogen receptor positive human breast cancer (MCF-7) cells in vitro and in vivo. A dimethylsulfoxide (DMSO) extract of Avlimil (0.001-100 microg Avlimil powder equivalents/mL media) was tested for its estrogenic and anti-estrogenic effects on the growth of MCF-7 cells in vitro. We observed that the DMSO extract of Avlimil at low concentrations (0.1-50 microg/mL media) dose-dependently increased MCF-7 cell proliferation in vitro, and Avlimil DMSO extract at 100 microg/mL inhibited the growth of MCF-7 cells in vitro. Avlimil and some constituents (black cohosh and licorice roots) of Avlimil were fractionated by using sequential solvent extraction (hexane, ethyl acetate, and methanol) and the activities of the fractions were monitored by effects on the growth of MCF-7 cells. Depending on dosage (0.1-100 microg/mL media) both stimulatory and inhibitory effects of the extracts on the growth of MCF-7 cells were observed. The effect of dietary Avlimil at dosages approximating human intake was evaluated using ovariectomized mice implanted with MCF-7 cells. Animals were fed diets containing 500 ppm or 1000 ppm Avlimil for 16 weeks. Dietary Avlimil at 500 ppm stimulated MCF-7 tumors, but Avlimil at 1000 ppm had no apparent effect on the growth of MCF-7 tumors. The observation of stimulated tumor growth in the absence of uterine wet weight gains suggest that estrogenic/anti-estrogenic effects of Avlimil we observed may be dosage- and target tissue-specific and that Avlimil may not be safe for women with estrogen-dependent breast cancer. The different biological effects of fractionated Avlimil components and the different concentration dependencies warrant further compound identification and dose-response studies, especially at recommended intake levels that could have estrogenic effects in women.

Proposal for single and mixture biological exposure limits for sevoflurane and nitrous oxide at low occupational exposure levels.

PubMed

Accorsi, Antonio; Valenti, Simona; Barbieri, Anna; Raffi, Giovanni Battista; Violante, Francesco Saverio

2003-03-01

Assessment of individual exposures to sevoflurane plus nitrous oxide (N(2)O) by biological monitoring of unmodified analytes in post-shift urine of exposed personnel. Anaesthetics in urine and breathing area were monitored in 124 subjects in 11 operating theatres. Passive samplers were collected after 2.5-7 h of exposure, at the same time as post-shift urinary samples, to evaluate the individual time-weighted average (TWA) exposures to sevoflurane and N(2)O. A static headspace sampler coupled with a gas chromatograph mass spectrometer was used for analytical determinations (sensitivity sufficient to reveal biological/environmental exposures of 0.1 microg/l(urine) and 50 ppb for sevoflurane, and 1 microg/l(urine) and 80 ppb for N(2)O). Median (range) post-shift urinary and environmental values were 1.2 microg/l(urine) (0.1-5.0) and 0.4 ppm (0.05-3.0) for sevoflurane ( n=107) and 10.9 microg/l(urine) (0.5-74.9) and 8.6 ppm (0.2-123.4) for N(2)O ( n=121) (all low-exposure range). At log-log regression, urinary levels closely correlated with environmental data (sevoflurane, r(2)=0.7538; N(2)O, r(2)=0.8749). Biological equivalent limits (BELs) based on National Institute for Occupational Safety and Health (NIOSH) TWA exposure limits, calculated as means of regression slope and y-intercept, were 3.6 microg/l(urine) for sevoflurane (corresponding to 2 ppm) and 22.3 microg/l(urine) for N(2)O (corresponding to 25 ppm). Individual "mixture BELs", which we calculated by applying the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) mix formula to biomarker values and using the obtained NIOSH-based BELs as a reference, closely correlated with mixture TLVs (rho=0.816, Lin's concordance test). CONCLUSIONS. We propose urinary sevoflurane as a new, specific, internal dose biomarker for routine biological monitoring of personal exposures among operating-theatre personnel, and use of reliable "mixture BELs" to provide safer levels of internal exposure for workers exposed to mixtures of sevoflurane and N(2)O, and conceivably also to other mixtures of toxicants with possible additive effects.