WorldWideScience

Sample records for lead isotopic analyses

  1. Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary

    Science.gov (United States)

    Ritson, P.I.; Bouse, R.M.; Flegal, A.R.; Luoma, S.N.

    1999-01-01

    Variations in stable lead isotopic composition (240Pb, 206Pb, 207Pb, 208Pb) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment, with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic composition in the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower 206Pb/207Pb, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachates from fourteen surface sediments and five marsh samples from the estuary were also analyzed. These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous among recently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural lead biodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that

  2. Authenticity of Benin metalworks evaluated by inductively coupled plasma mass spectrometry and lead isotope analyses

    Science.gov (United States)

    Fabbri, E.; Soffritti, C.; Merlin, M.; Vaccaro, C.; Garagnani, G. L.

    2017-05-01

    Two metal plaques and a cock statuette belonging to a private collection and stylistically consistent with the Royal Art of Benin (Nigeria) were investigated in order to verify their authenticity. The characterization of alloys and patinas were carried out by inductively coupled plasma mass spectrometry, optical microscopy, scanning electron microscopy and energy dispersion spectroscopy, and X-Ray diffraction spectrometry. Furthermore, thermal ionization mass spectrometry was used to assess the abundances of lead isotopes and to attempt a dating by the measurement of 210Pb/204Pb ratio. The results showed that all three artefacts were mainly composed of low lead-brass alloys, with relatively high concentrations of zinc, antimony, cadmium and aluminum in the solid copper solution. Microstructures were mostly dendritic, typical of as-cast brasses, and characterized by recrystallized non-homogeneous twinned grains in areas corresponding to surface decorations, probably due to multiple hammering steps followed by partial annealing treatments. The matrix was composed of a cored α-Cu solid solution together with non-metallic inclusions, lead globules and Sn-rich precipitates in interdendritic spaces. On the surface of all metalworks, both copper and zinc oxides, a non-continuous layer of sulphur-containing contaminants and chloride-containing compounds, were identified. The lead isotope results were consistent with brasses produced shortly before or after 1900 CE. Overall, the data obtained by different techniques supported the hypothesis that the three artefacts were not authentic.

  3. Identification of trace metal pollution in urban dust from kindergartens using magnetic, geochemical and lead isotopic analyses

    Science.gov (United States)

    Zhu, Zongmin; Sun, Guangyi; Bi, Xiangyang; Li, Zhonggen; Yu, Genhua

    2013-10-01

    In the present study, magnetic measurements were combined with geochemical analysis and stable Pb isotopic ratios to reveal the distribution and origination of trace metal pollutants in kindergarten dusts from a typical urban environment of Wuhan, central China. The geoaccumulation index (Igeo) of magnetic properties was more prominent than those of individual metals. The magnetic susceptibility (MS) and trace metals (Zn, Pb, and Cu) in this study together with published results from other Chinese cities formed a liner relationship, suggesting that metal contaminants in Chinese urban areas had similar MS to metal ratios, which could be used as an indicator for identification of pollution sources between Chinese cities and the other Asian cities. Stable Pb isotopic ratios (1.1125-1.1734 for 206Pb/207Pb and 2.4457-2.4679 for 208Pb/207Pb) in the urban dusts from Wuhan were characterized by higher 208Pb component in comparison with those from other Chinese cities. This result combined with principal component analysis (PCA) indicated that metal pollutants in the dusts were derived from industrial activities and coal combustion, whereas the traffic emissions were no longer a predominant pollution source in urban environment. Our study demonstrated that environmental magnetic methods could not only reveal the overall situation of trace metal contamination, but also prove evidence in the identification of pollution sources.

  4. Multivariate statistical and lead isotopic analyses approach to identify heavy metal sources in topsoil from the industrial zone of Beijing Capital Iron and Steel Factory.

    Science.gov (United States)

    Zhu, Guangxu; Guo, Qingjun; Xiao, Huayun; Chen, Tongbin; Yang, Jun

    2017-06-01

    Heavy metals are considered toxic to humans and ecosystems. In the present study, heavy metal concentration in soil was investigated using the single pollution index (PIi), the integrated Nemerow pollution index (PIN), and the geoaccumulation index (Igeo) to determine metal accumulation and its pollution status at the abandoned site of the Capital Iron and Steel Factory in Beijing and its surrounding area. Multivariate statistical (principal component analysis and correlation analysis), geostatistical analysis (ArcGIS tool), combined with stable Pb isotopic ratios, were applied to explore the characteristics of heavy metal pollution and the possible sources of pollutants. The results indicated that heavy metal elements show different degrees of accumulation in the study area, the observed trend of the enrichment factors, and the geoaccumulation index was Hg > Cd > Zn > Cr > Pb > Cu ≈ As > Ni. Hg, Cd, Zn, and Cr were the dominant elements that influenced soil quality in the study area. The Nemerow index method indicated that all of the heavy metals caused serious pollution except Ni. Multivariate statistical analysis indicated that Cd, Zn, Cu, and Pb show obvious correlation and have higher loads on the same principal component, suggesting that they had the same sources, which are related to industrial activities and vehicle emissions. The spatial distribution maps based on ordinary kriging showed that high concentrations of heavy metals were located in the local factory area and in the southeast-northwest part of the study region, corresponding with the predominant wind directions. Analyses of lead isotopes confirmed that Pb in the study soils is predominantly derived from three Pb sources: dust generated during steel production, coal combustion, and the natural background. Moreover, the ternary mixture model based on lead isotope analysis indicates that lead in the study soils originates mainly from anthropogenic sources, which contribute much more

  5. Lead Isotopes in Highway Runoff

    Science.gov (United States)

    Ferreira, M.; Lau, S.; Green, P. G.; Stenstrom, M. K.

    2011-12-01

    Lead (Pb) isotopes have been used extensively to study the provenance of lead pollution on air, water, and sediments. In this study, we measured Pb isotopes and Pb aqueous concentration in highway runoff in three west Los Angeles sites. Those three sites, part of a long-term study sponsored by the California Department of Transportation, represent small catchment areas, and host heavy traffic. In addition, there were no inputs of sand or salt to the highway because the sites are almost completely impervious and also due to the lack of snow to be controlled. Highway runoff from the three sites was collected for 7 storms during the 2004-2005 Winter. Grab samples were collected every 15 minutes during the first hour, and hourly afterwards. A total of 202 samples were collected and filtered into five size fractions (100μm). Aqueous concentration of Pb range from 0.08μg/L to 46.95μg/L (7.98±10.89μg/L) and it is not correlated with any of the lead isotope ratios. The 208Pb/206Pb ratio ranges from 1.983 to 2.075 (2.024±0.026) and there is no statistical difference for the mean value of the 208Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). However, the 208Pb/206Pb ratio of nearby soils yield 2.060±0.021 and it is statistically different from the ratios obtained for the highway runoff. This hints that the lead present in highway runoff does not come from local soils. The 207Pb/206Pb ratio ranges from 0.804 to 0.847 (0.827±0.011) and there is no statistical difference for the mean value of the 207Pb/206Pb ratio for the four particulate size fractions (0.45-8μm, 8-20μm, 20-100μm, >100μm). Surprisingly, there is also no statistical difference with the 207Pb/206Pb ratio of nearby soils (0.833±0.009).

  6. Stable isotopic analyses in paleoclimatic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Wigand, P.E. [Univ. and Community College System of Nevada, Reno, NV (United States)

    1995-09-01

    Most traditional paleoclimatic proxy data have inherent time lags between climatic input and system response that constrain their use in accurate reconstruction of paleoclimate chronology, scaling of its variability, and the elucidation of the processes that determine its impact on the biotic and abiotic environment. With the exception of dendroclimatology, and studies of short-lived organisms and pollen recovered from annually varved lacustrine sediments, significant periods of time ranging from years, to centuries, to millennia may intervene between climate change and its first manifestation in paleoclimatic proxy data records. Reconstruction of past climate through changes in plant community composition derived from pollen sequences and plant remains from ancient woodrat middens, wet environments and dry caves all suffer from these lags. However, stable isotopic analyses can provide more immediate indication of biotic response to climate change. Evidence of past physiological response of organisms to changes in effective precipitation as climate varies can be provided by analyses of the stable isotopic content of plant macrofossils from various contexts. These analyses consider variation in the stable isotopic (hydrogen, oxygen and carbon) content of plant tissues as it reflects (1) past global or local temperature through changes in meteoric (rainfall) water chemistry in the case of the first two isotopes, and (2) plant stress through changes in plant respiration/transpiration processes under differing water availability, and varying atmospheric CO, composition (which itself may actually be a net result of biotic response to climate change). Studies currently being conducted in the Intermountain West indicate both long- and short-term responses that when calibrated with modem analogue studies have the potential of revealing not only the timing of climate events, but their direction, magnitude and rapidity.

  7. The identification of lead ammunition as a source of lead exposure in First Nations: The use of lead isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Leonard J.S. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: ljtsuji@fes.uwaterloo.ca; Wainman, Bruce C. [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Martin, Ian D. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Sutherland, Celine [Attawapiskat First Nation Health Services, Attawapiskat, Ontario, P0L 1A0 (Canada); Weber, Jean-Philippe; Dumas, Pierre [Centre de toxicologie, Institut national de sante publique du Quebec, Quebec City, Quebec, G1V 5B3 (Canada); Nieboer, Evert [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Institute of Community Medicine, University of Tromso, Tromso N-9037 (Norway)

    2008-04-15

    The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (p < 0.05) positive correlations for {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb, and a significant negative correlation for {sup 208}Pb/{sup 206}Pb, as predicted if leaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

  8. The identification of lead ammunition as a source of lead exposure in First Nations: the use of lead isotope ratios.

    Science.gov (United States)

    Tsuji, Leonard J S; Wainman, Bruce C; Martin, Ian D; Sutherland, Celine; Weber, Jean-Philippe; Dumas, Pierre; Nieboer, Evert

    2008-04-15

    The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of (206)Pb/(204)Pb and (206)Pb/(207)Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (pleaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

  9. Lead Contamination in Cocoa and Cocoa Products: Isotopic Evidence of Global Contamination

    National Research Council Canada - National Science Library

    Charley W. Rankin; Jerome O. Nriagu; Jugdeep K. Aggarwal; Toyin A. Arowolo; Kola Adebayo; A. Russell Flegal

    2005-01-01

    In this article we present lead concentrations and isotopic compositions from analyses of cocoa beans, their shells, and soils from six Nigerian cocoa farms, and analyses of manufactured cocoa and chocolate products...

  10. Advanced Mass Spectrometers for Hydrogen Isotope Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Chastagner, P.

    2001-08-01

    This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

  11. A new method for stable lead isotope extraction from seawater

    Energy Technology Data Exchange (ETDEWEB)

    Zurbrick, Cheryl M., E-mail: CZurbric@ucsc.edu [WIGS, Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Gallon, Céline [Institute of Marine Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Flegal, A. Russell [WIGS, Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Institute of Marine Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2013-10-24

    Graphical abstract: -- Highlights: •We present a relatively fast (2.5–6.5 h), semi-automated system to extract Pb from seawater. •Extraction requires few chemicals and has a relatively low blank (0.7 pmol kg{sup −1}). •We compare analyses of Pb isotopes by HR ICP-MS with those by MC-ICP-MS. -- Abstract: A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650 M{sup ®} resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for {sup 206}Pb/{sup 207}Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to {sup 206}Pb, {sup 207}Pb, and {sup 208}Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values.

  12. Tracing changes in atmospheric sources of lead contamination using lead isotopic compositions in Australian red wine.

    Science.gov (United States)

    Kristensen, Louise Jane; Taylor, Mark Patrick; Evans, Andrew James

    2016-07-01

    Air quality data detailing changes to atmospheric composition from Australia's leaded petrol consumption is spatially and temporally limited. In order to address this data gap, wine was investigated as a potential proxy for atmospheric lead conditions. Wine spanning sixty years was collected from two wine regions proximal to the South Australian capital city, Adelaide, and analysed for lead concentration and lead and strontium isotopic composition for source apportionment. Maximum wine lead concentrations (328 μg/L) occur prior to the lead-in-air monitoring in South Australia in the later 1970s. Wine lead concentrations mirror available lead-in-air measurements and show a declining trend reflecting parallel reductions in leaded petrol emissions. Lead from petrol dominated the lead in wine ((206)Pb/(207)Pb: 1.086; (208)Pb/(207)Pb: 2.360) until the introduction of unleaded petrol, which resulted in a shift in the wine lead isotopic composition closer to vineyard soil ((206)Pb/(207)Pb: 1.137; (208)Pb/(207)Pb: 2.421). Current mining activities or vinification processes appear to have no impact with recent wine samples containing less than 4 μg/L of lead. This study demonstrates wine can be used to chronicle changes in environmental lead emissions and is an effective proxy for atmospherically sourced depositions of lead in the absence of air quality data.

  13. Worldwide lead-isotope ratio in bivalves and sediments

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Jacobsen, Gitte; Strand, Jakob

    The lead-isotope ratio have been used to assess and identify impact of leaded gasoline, coal combustion and  mineral activities[ref 1] due to the difference in 206Pb (~52%), 207Pb (~24%) and 208Pb (~23%) isotope ratios. The source of these differences is the decaying of the parent isotopes of 238U...

  14. Analysing Groundwater Using the 13C Isotope

    Science.gov (United States)

    Awad, Sadek

    The stable isotope of the carbon atom (13C) give information about the type of the mineralisation of the groundwater existing during the water seepage and about the recharge conditions of the groundwater. The concentration of the CO2(aq.) dissolved during the infiltration of the water through the soil's layers has an effect on the mineralisation of this water. The type of the photosynthesis's cycle (C-3 or C-4 carbon cycle) can have a very important role to determine the conditions (closed or open system) of the mineralisation of groundwater. The isotope 13C of the dissolved CO2 in water give us a certain information about the origin and the area of pollution of water. The proportion of the biogenic carbon and its percentage in the mineralisation of groundwater is determined by using the isotope 13C.

  15. Rapid lead isotope analysis of archaeological metals by multiple-collector inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Baker, J.A.; Stos, S.; Waight, Tod Earle

    2006-01-01

    Lead isotope ratios in archaeological silver and copper were determined by MC-ICPMS using laser ablation and bulk dissolution without lead purification. Laser ablation results on high-lead metals and bulk solution analyses on all samples agree within error of TIMS data, suggesting that problems...... from isobaric interferences and/or mass bias variations due to the presence of matrix elements are insignificant. Inaccurate laser ablation analyses on low-lead copper reflect erroneous mass bias corrections from use of a non-matrix matched standard. However, in most cases, silver and copper...... are analysable for lead isotopes by bulk dissolution or laser ablation MC-ICPMS with simplified sample preparation....

  16. Discovery of the thallium, lead, bismuth, and polonium isotopes

    Science.gov (United States)

    Fry, C.; Thoennessen, M.

    2013-05-01

    Forty-two thallium, forty-two lead, forty-one bismuth, and forty-two polonium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  17. Discovery of the thallium, lead, bismuth, and polonium isotopes

    CERN Document Server

    Fry, C

    2012-01-01

    Currently, forty-two thallium, forty-two lead, forty-one bismuth, and forty-two polonium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  18. Lead sources and transfer in the coastal Mediterranean: evidence from stable lead isotopes in marine particles

    Science.gov (United States)

    Alleman, L. Y.; Hamelin, B.; Véron, A. J.; Miquel, J.-C.; Heussner, S.

    Time series of settling and suspended particles have been collected by sediment traps and in situ pumps respectively, under contrasted hydrographic conditions in the Gulf of Lions and the Ligurian Sea, northwestern Mediterranean. Lead concentrations measured in sediment trap samples vary from 41±7 ppm in the Ligurian Sea to 58±10 ppm in the Gulf of Lions. These concentrations, 2-10 times lower than those measured previously in the Gulf of Lions, reflect the reduction of lead fallout from gasoline during the last decade. While atmospheric lead still originates mainly from anthropogenic emissions (automotive and industrial exhausts), stable lead isotopes demonstrate that anthropogenic and lithogenic lead are in similar proportions in the marine particles from the northwestern Mediterranean. Sequential extraction analyses performed on trap samples suggest that the isotopic variations can be explained by a three-component mixing between anthropogenic, natural soluble, and natural refractory sources. In the suspended particulate matter from the Gulf of Lions, lead concentrations range from 0.2 to 30 ng/ l, with isotopic compositions comparable to those of the settling particles ( 206Pb/ 207Pb from 1.165 to 1.178). This indicates a common origin in these two types of particles, probably mainly controlled by the Rhône River discharge and by resuspension processes on the continental shelf. By contrast, lead concentrations are lower in the suspended matter samples from the Ligurian Sea (0.5 to 1.7 ng/ l). In this case, the isotopic signature (1.165±0.002) is in equilibrium with the dissolved fraction, as previously found in other oligotrophic sites in the open ocean, where the suspended particles are mainly of biological origin and lead essentially authigenic in these particles.

  19. Linking cases of illegal shootings of the endangered California condor using stable lead isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Finkelstein, Myra E., E-mail: myraf@ucsc.edu [Microbiology and Environmental Toxicology Department, University of California, Santa Cruz, CA 95064 (United States); Kuspa, Zeka E. [Microbiology and Environmental Toxicology Department, University of California, Santa Cruz, CA 95064 (United States); Welch, Alacia [National Park Service, Pinnacles National Park, 5000 Highway 146, Paicines, CA 95043 (United States); Eng, Curtis; Clark, Michael [Los Angeles Zoo and Botanical Gardens, 5333 Zoo Drive, Los Angeles, CA 90027 (United States); Burnett, Joseph [Ventana Wildlife Society, 19045 Portola Dr. Ste. F-1, Salinas, CA 93908 (United States); Smith, Donald R. [Microbiology and Environmental Toxicology Department, University of California, Santa Cruz, CA 95064 (United States)

    2014-10-15

    Lead poisoning is preventing the recovery of the critically endangered California condor (Gymnogyps californianus) and lead isotope analyses have demonstrated that ingestion of spent lead ammunition is the principal source of lead poisoning in condors. Over an 8 month period in 2009, three lead-poisoned condors were independently presented with birdshot embedded in their tissues, evidencing they had been shot. No information connecting these illegal shooting events existed and the timing of the shooting(s) was unknown. Using lead concentration and stable lead isotope analyses of feathers, blood, and recovered birdshot, we observed that: i) lead isotope ratios of embedded shot from all three birds were measurably indistinguishable from each other, suggesting a common source; ii) lead exposure histories re-constructed from feather analysis suggested that the shooting(s) occurred within the same timeframe; and iii) two of the three condors were lead poisoned from a lead source isotopically indistinguishable from the embedded birdshot, implicating ingestion of this type of birdshot as the source of poisoning. One of the condors was subsequently lead poisoned the following year from ingestion of a lead buckshot (blood lead 556 µg/dL), illustrating that ingested shot possess a substantially greater lead poisoning risk compared to embedded shot retained in tissue (blood lead ∼20 µg/dL). To our knowledge, this is the first study to use lead isotopes as a tool to retrospectively link wildlife shooting events. - Highlights: • We conducted a case-based analysis of illegal shootings of California condors. • Blood and feather Pb isotopes were used to reconstruct the illegal shooting events. • Embedded birdshot from the three condors had the same Pb isotope ratios. • Feather and blood Pb isotopes indicated that the condors were shot in a common event. • Ingested shot causes substantially greater lead exposure compared to embedded shot.

  20. Medical Isotope Production Analyses In KIPT Neutron Source Facility

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    Medical isotope production analyses in Kharkov Institute of Physics and Technology (KIPT) neutron source facility were performed to include the details of the irradiation cassette and the self-shielding effect. An updated detailed model of the facility was used for the analyses. The facility consists of an accelerator-driven system (ADS), which has a subcritical assembly using low-enriched uranium fuel elements with a beryllium-graphite reflector. The beryllium assemblies of the reflector have the same outer geometry as the fuel elements, which permits loading the subcritical assembly with different number of fuel elements without impacting the reflector performance. The subcritical assembly is driven by an external neutron source generated from the interaction of 100-kW electron beam with a tungsten target. The facility construction was completed at the end of 2015, and it is planned to start the operation during the year of 2016. It is the first ADS in the world, which has a coolant system for removing the generated fission power. Argonne National Laboratory has developed the design concept and performed extensive design analyses for the facility including its utilization for the production of different radioactive medical isotopes. 99Mo is the parent isotope of 99mTc, which is the most commonly used medical radioactive isotope. Detailed analyses were performed to define the optimal sample irradiation location and the generated activity, for several radioactive medical isotopes, as a function of the irradiation time.

  1. Tables for determining lead, uranium, and thorium isotope ages

    Science.gov (United States)

    Schonfeld, E.

    1974-01-01

    Tables for determining lead, uranium, and thorium isotope ages are presented in the form of computer printouts. Decay constants, analytical expressions for the functions evaluated, and the precision of the calculations are briefly discussed.

  2. Lead isotopes as a supplementary tool in the routine evaluation of household lead hazards.

    OpenAIRE

    Gwiazda, R H; Smith, D. R.

    2000-01-01

    The advent of magnetic sector inductively coupled plasma-mass spectrometry (ICP-MS) allows rapid, accurate, and precise measurement of lead isotopes in environmental and biological samples at a lower cost than traditional methods. This may increase the feasibility of including lead isotope measurements as a routine tool to identify household sources of lead exposure to children. Here, we present three household case studies to illustrate how lead hazard evaluations by an environmental special...

  3. Tracing source pollution in soils using cadmium and lead isotopes.

    Science.gov (United States)

    Cloquet, C; Carignan, J; Libourel, G; Sterckeman, T; Perdrix, E

    2006-04-15

    Tracing the source of heavy metals in the environment is of key importance for our understanding of their pollution and natural cycles in the surface Earth reservoirs. Up to now, most exclusively Pb isotopes were used to effectively trace metal pollution sources in the environment. Here we report systematic variations of Cd isotope ratios measured in polluted topsoils surrounding a Pb-Zn refinery plant in northern France. Fractionated Cd was measured in soil samples surrounding the refinery, and this fractionation can be attributed to the refining processes. Despite the Cd isotopic ratios being precisely measured, the obtained uncertainties are still large compared to the total isotopic variation. Nevertheless, for the first time, Cd isotopically fractionated by industrial processes may be traced in the environment. On the same samples, Pb isotope systematics suggested that materials actually used by the refinery were not the major source of Pb in soils, probably because refined ore origins changed over the 100 years of operation. On the other hand, Cd isotopes and concentrations measured in topsoils allowed identification of three main origins (industrial dust and slag and agriculture), assuming that all Cd ores are not fractionated, as suggested by terrestrial rocks so far analyzed, and calculation of their relative contributions for each sampling point. Understanding that this refinery context was an ideal situation for such a study, our results lead to the possibility of tracing sources of anthropogenic Cd and better constrain mixing processes, fluxes, transport, and phasing out of industrial input in nature.

  4. Lead contamination in cocoa and cocoa products: isotopic evidence of global contamination.

    Science.gov (United States)

    Rankin, Charley W; Nriagu, Jerome O; Aggarwal, Jugdeep K; Arowolo, Toyin A; Adebayo, Kola; Flegal, A Russell

    2005-10-01

    In this article we present lead concentrations and isotopic compositions from analyses of cocoa beans, their shells, and soils from six Nigerian cocoa farms, and analyses of manufactured cocoa and chocolate products. The average lead concentration of cocoa beans was cocoa and chocolate products were as high as 230 and 70 ng/g, respectively, which are consistent with market-basket surveys that have repeatedly listed lead concentrations in chocolate products among the highest reported for all foods. One source of contamination of the finished products is tentatively attributed to atmospheric emissions of leaded gasoline, which is still being used in Nigeria. Because of the high capacity of cocoa bean shells to adsorb lead, contamination from leaded gasoline emissions may occur during the fermentation and sun-drying of unshelled beans at cocoa farms. This mechanism is supported by similarities in lead isotopic compositions of cocoa bean shells from the different farms (206Pb/207Pb = 1.1548-1.1581; 208Pb/207Pb = 2.4344-2.4394) with those of finished cocoa products (206Pb/207Pb = 1.1475-1.1977; 208Pb/207Pb = 2.4234-2.4673). However, the much higher lead concentrations and larger variability in lead isotopic composition of finished cocoa products, which falls within the global range of industrial lead aerosols, indicate that most contamination occurs during shipping and/or processing of the cocoa beans and the manufacture of cocoa and chocolate products.

  5. Sargipali galenas: Unusual lead-isotope data from eastern India

    Science.gov (United States)

    Vishwakarma, Rajesh K.; Ulabhaje, A. V.

    1991-04-01

    The Sargipali sulphide deposit, hosted by a sequence of metasediments of the Precambrian Gangpur Series, represents the stratiform and stratabound Pb-Cu mineralization. Lead-isotope analyses obtained from six galena samples of different forms and stratigraphical levels, yielded a model Pb age of 1665 Ma, which predates the episodes of deformation and metamorphism (˜ 850 Ma) as well as syn-to late-tectonic magmatism. The model Pb age, on the contrary, shows a relationship to the closing phase of the Gangpur sedimentation (1700 Ma) in a shallow-water marine environment. The notable paucity of the interlayered volcanic rock in the deposit and its Pb-rich nature possibly point to its being the sedimentary exhalative (SEDEX) type. Documentary evidence for the Pb component from the geological environment of the “upper continental crust” is revealed by an exceptionally high μ(= 238U/204Pb) and the slightly above average W(= 232Th/238U) values. These indicate that the source rock was initially rich in U-Th-Pb concentration. For the Sargipali ore Pb, the parent is assumed to be late Archean-lower Proterozoic soda granite.

  6. Worldwide lead-isotope ratio in bivalves and sediments

    DEFF Research Database (Denmark)

    Larsen, Martin Mørk; Jacobsen, Gitte; Strand, Jakob

    The lead-isotope ratio have been used to assess and identify impact of leaded gasoline, coal combustion and  mineral activities[ref 1] due to the difference in 206Pb (~52%), 207Pb (~24%) and 208Pb (~23%) isotope ratios. The source of these differences is the decaying of the parent isotopes of 238U...... to 206Pb, 235U to 207Pb and 232Th to 208Pb. 204Pb is the only stable Pb isotope usually contributing 1% of the total Pb. Differences in 206Pb/207Pb ratio ranges from 1.06 to 1.10 in old Pb ores (e.g. the time of the roman empire), whereas recent mining from radiogenic (high U and Th contents) ores can.......35% with recoveries of  98.50 to 100.03%. Geographical differences and comparison with literature values for the different regions will be presented, together with a discussion on the suitability of ICP-quadropole-MS for isotope ratio determinations. ...

  7. Oxygen Isotopic Analyses of Water Extracted from Lunar Samples

    Science.gov (United States)

    Nunn Martinez, M.; Thiemens, M. H.

    2014-12-01

    Oxygen exists in lunar materials in distinct phases having unique sources and equilibration histories. The oxygen isotopic composition (δ17O, δ18O) of various components of lunar materials has been studied extensively, but analyses of water in these samples are relatively sparse [1-3]. Samples collected on the lunar surface reflect not only the composition of their source reservoirs but also contributions from asteroidal and cometary impacts, interactions with solar wind and cosmic radiation, among other surface processes. Isotopic characterization of oxygen in lunar water could help resolve the major source of water in the Earth-Moon system by revealing if lunar water is primordial, asteroidal, or cometary in origin [1]. Methods: A lunar rock/soil sample is pumped to high vacuum to remove physisorbed water before heating step-wise to 50, 150, and 1000°C to extract extraterrestrial water without terrestrial contamination. The temperature at which water is evolved is proportional to the strength with which the water is bound in the sample and the relative difficulty of exchanging oxygen atoms in that water. This allows for the isolated extraction of water bound in different phases, which could have different source reservoirs and/or histories, as evidenced by the mass (in)dependence of oxygen compositions. A low blank procedure was developed to accommodate the low water content of lunar material [4]. Results: Oxygen isotopic analyses of lunar water extracted by stepwise heating lunar basalts and breccias with a range of compositions, petrologic types, and surface exposure ages will be presented. The cosmic ray exposure age of these samples varies by two orders of magnitude, and we will consider this in discussing the effects of solar wind and cosmic radiation on the oxygen isotopic composition (Δ17O). I will examine the implications of our water analyses for the composition of the oxygen-bearing reservoir from which that water formed, the effects of surface

  8. Monitoring steel bridge renovation using lead isotopic tracing.

    Science.gov (United States)

    Salome, Fred; Gulson, Brian; Chiaradia, Massimo; Davis, Jeffrey; Morris, Howard

    2017-05-01

    Monitoring removal of lead (Pb) paint from steel structures usually involves analysis of environmental samples for total lead and determination of blood Pb levels of employees involved in the Pb paint removal. We used high precision Pb isotopic tracing for a bridge undergoing Pb paint removal to determine if Pb in the environmental and blood samples originated from the bridge paint. The paint system on the bridge consisted of an anti-corrosive red Pb primer top-coated with a Micaceous Iron Oxide (MIO) alkyd. Analysis of the red Pb primer gave uniform isotopic ratios indicative of Pb from the geologically-ancient Broken Hill mines in western New South Wales, Australia. Likewise waste abrasive material, as anticipated, had the same isotopic composition as the paint. The isotopic ratios for other samples lay on 2 separate linear arrays on a(207)Pb/(204)Pb versus (206)Pb/(204)Pb diagram, one largely defined by gasoline and the majority of the ambient air data, and the other by data for one sample each of gasoline and ambient air and underwater sediments. Isotopic ratios in background ambient air samples for the project were characteristic of leaded gasoline. Air sampling during paint removal showed a contribution of paint Pb ranging from about 20 to 40%. Isotopic ratios in the blood of 8 employees prior to the commencement of work showed that 6 of these had been previously exposed to the Broken Hill Pb possibly from earlier bridge paint removal projects. One subject appeared to have increased exposure to Pb probably from the paint renovations.

  9. Resolving the stellar sources of isotopically rare presolar silicate grains through Mg and Fe isotopic analyses

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ann N.; Messenger, Scott, E-mail: lan-anh.n.nguyen@nasa.gov [Robert M. Walker Laboratory for Space Science, Astromaterials Research and Exploration Science Directorate, NASA Johnson Space Center, Houston, TX 77058 (United States)

    2014-04-01

    We conducted multi-element isotopic analyses of 11 presolar silicate grains from the Acfer 094 meteorite having unusual O isotopic compositions. Eight grains are {sup 18}O-rich, one is {sup 16}O-rich, and two are extremely {sup 17}O-rich. We constrained the grains' stellar sources by measuring their Si and Mg isotopic ratios, and also the {sup 54}Fe/{sup 56}Fe and {sup 57}Fe/{sup 56}Fe ratios for five grains. The Mg and Fe isotopic measurements were conducted after surrounding matrix grains were removed for more accurate ratios. Most of the {sup 18}O-rich silicates had anomalous Mg isotopic ratios, and their combined isotopic constraints are consistent with origins in low-mass Type II supernovae (SNe II) rather than high-metallicity stars. The isotopic ratios of the {sup 16}O-rich silicate are also consistent with an SN origin. Mixing small amounts of interior stellar material with the stellar envelope replicated all measured isotopic ratios except for {sup 29}Si/{sup 28}Si and {sup 54}Fe/{sup 56}Fe in some grains. The {sup 29}Si/{sup 28}Si ratios of all SN-derived grains are matched by doubling the {sup 29}Si yield in the Ne- and Si-burning zones. The {sup 54}Fe/{sup 56}Fe ratios of the grains imply elemental fractionation in the Si/S zone, or introduction of isotopically solar Fe by secondary processing. The two highly {sup 17}O-rich silicates exhibited significant {sup 25}Mg and/or {sup 26}Mg enrichments and their isotopic ratios are best explained by strong dilution of 1.15 M {sub ☉} CO nova matter. We estimate that ∼12% and 1% of presolar silicates have SN and nova origins, respectively, similar to presolar SiC and oxides. This implies that asymptotic giant branch stars are the dominant dust producers in the galaxy.

  10. Trophic structure in a seabird host-parasite food web: insights from stable isotope analyses.

    Directory of Open Access Journals (Sweden)

    Elena Gómez-Díaz

    Full Text Available Ecological studies on food webs rarely include parasites, partly due to the complexity and dimensionality of host-parasite interaction networks. Multiple co-occurring parasites can show different feeding strategies and thus lead to complex and cryptic trophic relationships, which are often difficult to disentangle by traditional methods. We analyzed stable isotope ratios of C ((13C/(12C, delta(13C and N ((15N/(14N, delta(15N of host and ectoparasite tissues to investigate trophic structure in 4 co-occurring ectoparasites: three lice and one flea species, on two closely related and spatially segregated seabird hosts (Calonectris shearwaters. delta(13C isotopic signatures confirmed feathers as the main food resource for the three lice species and blood for the flea species. All ectoparasite species showed a significant enrichment in delta(15N relatively to the host tissue consumed (discrimination factors ranged from 2 to 5 per thousand depending on the species. Isotopic differences were consistent across multiple host-ectoparasite locations, despite of some geographic variability in baseline isotopic levels. Our findings illustrate the influence of both ectoparasite and host trophic ecology in the isotopic structuring of the Calonectris ectoparasite community. This study highlights the potential of stable isotope analyses in disentangling the nature and complexity of trophic relationships in symbiotic systems.

  11. Lead Contamination in Cocoa and Cocoa Products: Isotopic Evidence of Global Contamination

    OpenAIRE

    Rankin, Charley W.; Nriagu, Jerome O.; Aggarwal, Jugdeep K.; Arowolo, Toyin A.; Adebayo, Kola; Flegal, A. Russell

    2005-01-01

    In this article we present lead concentrations and isotopic compositions from analyses of cocoa beans, their shells, and soils from six Nigerian cocoa farms, and analyses of manufactured cocoa and chocolate products. The average lead concentration of cocoa beans was ≤ 0.5 ng/g, which is one of the lowest reported values for a natural food. In contrast, lead concentrations of manufactured cocoa and chocolate products were as high as 230 and 70 ng/g, respectively, which are consistent with mark...

  12. Lead Isotope Characterization of Petroleum Fuels in Taipei, Taiwan

    Directory of Open Access Journals (Sweden)

    Pei-Hsuan Yao

    2015-04-01

    Full Text Available Leaded gasoline in Taiwan was gradually phased out from 1983 to 2000. However, it is unclear whether unleaded gasoline still contributes to atmospheric lead (Pb exposure in urban areas. In this study, Pb isotopic compositions of unleaded gasolines, with octane numbers of 92, 95, 98, and diesel from two local suppliers in Taipei were determined by multi-collector inductively coupled plasma mass spectrometry with a two-sigma uncertainty of ± 0.02 %. Lead isotopic ratios of vehicle exhaust (208Pb/207Pb: 2.427, 206Pb/207Pb: 1.148, as estimated from petroleum fuels overlap with the reported aerosol data. This agreement indicates that local unleaded petroleum fuels, containing 10–45 ng·Pb·g−1, are merely one contributor among various sources to urban aerosol Pb. Additionally, the distinction between the products of the two companies is statistically significant in their individual 208Pb/206Pb ratios (p-value < 0.001, t test. Lead isotopic characterization appears to be applicable as a “fingerprinting” tool for tracing the sources of Pb pollution.

  13. Asian industrial lead inputs to the North Pacific evidenced by lead concentrations and isotopic compositions in surface waters and aerosols.

    Science.gov (United States)

    Gallon, Céline; Ranville, Mara A; Conaway, Christopher H; Landing, William M; Buck, Clifton S; Morton, Peter L; Flegal, A Russell

    2011-12-01

    Recent trends of atmospheric lead deposition to the North Pacific were investigated with analyses of lead in aerosols and surface waters collected on the fourth Intergovernmental Oceanographic Commission Contaminant Baseline Survey from May to June, 2002. Lead concentrations of the aerosols varied by 2 orders of magnitude (0.1-26.4 pmol/m(3)) due in part to variations in dust deposition during the cruise. The ranges in lead aerosol enrichment factors relative to iron (1-119) and aluminum (3-168) were similar, evidencing the transport of Asian industrial lead aerosols across the North Pacific. The oceanic deposition of some of those aerosols was substantiated by the gradient of lead concentrations of North Pacific waters, which varied 3-fold (32.7-103.5 pmol/kg), were highest along with the Asian margin of the basin, and decreased eastward. The hypothesized predominance of Asian industrial lead inputs to the North Pacific was further corroborated by the lead isotopic composition of ocean surface waters ((206)Pb/(207)Pb = 1.157-1.169; (208)Pb/(206)Pb = 2.093-2.118), which fell within the range of isotopic ratios reported in Asian aerosols that are primarily attributed to Chinese industrial lead emissions.

  14. Lead isotope ratios as a tracer for lead contamination sources: A lake Andong case study

    Directory of Open Access Journals (Sweden)

    Kim Y. H

    2013-04-01

    Full Text Available The objective of this study was to evaluate stable Pb isotope signatures as a tracer for Pb contamination in Lake Andong. For Pb isotope analysis, we collected water and sediment from Lake Andong, particles in the air, soils, and stream water, mine tailings, sludge and wastewater from zinc smelting around lake Andong watershed. The results showed that Pb isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for zinc concentrate were 18.809 ± 0.322, 15.650 ± 0.062, and 38.728 ± 0.421, respectively. In wastewater, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb were 17.363 ± 0.133, 15.550 ± 0.025, and 37.217 ± 0.092, respectively. Additionally, isotopic ratio values (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for sludge were 17.515 ± 0.155, 15.537 ± 0.018, and 37.357 ± 0.173, respectively. These values were similar to those in zinc and lead concentrate originated from Canada and South America. In contrast, Pb isotope ratios of soil, tailings and sediment from Lake Andong were similar to those of Korean ore. Atmospheric particles showed different patterns of Pb isotope ratios from sediments, soils, and zinc smelting and this needs further investigation in order to identify atmospheric Pb sources.

  15. Regional lead isotope study of a polluted river catchment: River Wear, Northern England, UK.

    Science.gov (United States)

    Shepherd, Thomas J; Chenery, Simon R N; Pashley, Vanessa; Lord, Richard A; Ander, Louise E; Breward, Neil; Hobbs, Susan F; Horstwood, Matthew; Klinck, Benjamin A; Worrall, Fred

    2009-08-15

    High precision, lead isotope analyses of archived stream sediments from the River Wear catchment, northeast England (1986-88), provide evidence for three main sources of anthropogenic lead pollution; lead mining, industrial lead emissions and leaded petrol. In the upper catchment, pollution is totally controlled and dominated by large lead discharges from historic mining centres in the North Pennine Orefield ((208)Pb/(206)Pb, (207)Pb/(206)Pb ratios range from 2.0744-2.0954 and 0.8413-0.8554 respectively). In the lower catchment, co-extensive with the Durham Coalfield and areas of high population density, pollution levels are lower and regionally more uniform. Isotope ratios are systematically higher than in the upper catchment ((208)Pb/(206)Pb, (207)Pb/(206)Pb ratios range from 2.0856-2.1397 and 0.8554-0.8896 respectively) and far exceed values determined for the geogenic regional background. Here, the pollution is characterised by the atmospheric deposition of industrial lead and petrol lead. Lead derived from the combustion of coal, although present, is masked by the other two sources. Recent sediments from the main channel of the River Wear are isotopically indistinguishable from older, low order stream sediments of the North Pennine Orefield, indicating that contamination of the river by lead mining waste (up to several 1000 mg/kg Pb at some locations) continues to pose an environmental problem; a pattern that can be traced all the way to the tidal reach. Using within-catchment isotope variation and sediment lead concentrations, estimates can be made of the discharges from discrete mines or groups of mines to the overall level of lead pollution in the River Wear. As well as providing information pertinent to source apportionment and on-going catchment remediation measures, the database is a valuable resource for epidemiologists concerned with the health risks posed by environmental lead.

  16. Regional lead isotope study of a polluted river catchment: River Wear, Northern England, UK

    Energy Technology Data Exchange (ETDEWEB)

    Shepherd, Thomas J., E-mail: shepherdtj@aol.com [Department of Earth Sciences, University of Durham, Science Laboratories, Durham DH1 3LE (United Kingdom); Chenery, Simon R.N. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Pashley, Vanessa [NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Lord, Richard A. [School of Science and Technology, University of Teesside, Middlesbrough, Tees Valley TS1 3BA (United Kingdom); Ander, Louise E.; Breward, Neil; Hobbs, Susan F. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Horstwood, Matthew [NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Klinck, Benjamin A. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Worrall, Fred [Department of Earth Sciences, University of Durham, Science Laboratories, Durham DH1 3LE (United Kingdom)

    2009-08-15

    High precision, lead isotope analyses of archived stream sediments from the River Wear catchment, northeast England (1986-88), provide evidence for three main sources of anthropogenic lead pollution; lead mining, industrial lead emissions and leaded petrol. In the upper catchment, pollution is totally controlled and dominated by large lead discharges from historic mining centres in the North Pennine Orefield ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb ratios range from 2.0744-2.0954 and 0.8413-0.8554 respectively). In the lower catchment, co-extensive with the Durham Coalfield and areas of high population density, pollution levels are lower and regionally more uniform. Isotope ratios are systematically higher than in the upper catchment ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb ratios range from 2.0856-2.1397 and 0.8554-0.8896 respectively) and far exceed values determined for the geogenic regional background. Here, the pollution is characterised by the atmospheric deposition of industrial lead and petrol lead. Lead derived from the combustion of coal, although present, is masked by the other two sources. Recent sediments from the main channel of the River Wear are isotopically indistinguishable from older, low order stream sediments of the North Pennine Orefield, indicating that contamination of the river by lead mining waste (up to several 1000 mg/kg Pb at some locations) continues to pose an environmental problem; a pattern that can be traced all the way to the tidal reach. Using within-catchment isotope variation and sediment lead concentrations, estimates can be made of the discharges from discrete mines or groups of mines to the overall level of lead pollution in the River Wear. As well as providing information pertinent to source apportionment and on-going catchment remediation measures, the database is a valuable resource for epidemiologists concerned with the health risks posed by environmental lead.

  17. Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden.

    Science.gov (United States)

    Bindler, Richard

    2011-08-01

    Clair Patterson and colleagues demonstrated already four decades ago that the lead cycle was greatly altered on a global scale by humans. Moreover, this change occurred long before the implementation of monitoring programs designed to study lead and other trace metals. Patterson and colleagues also developed stable lead isotope analyses as a tool to differentiate between natural and pollution-derived lead. Since then, stable isotope analyses of sediment, peat, herbaria collections, soils, and forest plants have given us new insights into lead biogeochemical cycling in space and time. Three important conclusions from our studies of lead in the Swedish environment conducted over the past 15 years, which are well supported by extensive results from elsewhere in Europe and in North America, are: (1) lead deposition rates at sites removed from major point sources during the twentieth century were about 1,000 times higher than natural background deposition rates a few thousand years ago (~10 mg Pb m(-2) year(-1) vs. 0.01 mg Pb m(-2) year(-1)), and even today (~1 mg Pb m(-2) year(-1)) are still almost 100 times greater than natural rates. This increase from natural background to maximum fluxes is similar to estimated changes in body burdens of lead from ancient times to the twentieth century. (2) Stable lead isotopes ((206)Pb/(207)Pb ratios shown in this paper) are an effective tool to distinguish anthropogenic lead from the natural lead present in sediments, peat, and soils for both the majority of sites receiving diffuse inputs from long range and regional sources and for sites in close proximity to point sources. In sediments >3,500 years and in the parent soil material of the C-horizon, (206)Pb/(207)Pb ratios are higher, 1.3 to >2.0, whereas pollution sources and surface soils and peat have lower ratios that have been in the range 1.14-1.18. (3) Using stable lead isotopes, we have estimated that in southern Sweden the cumulative anthropogenic burden of

  18. Intruder bands and configuration mixing in the lead isotopes

    OpenAIRE

    Fossion, R.; Heyde, K.; Thiamova, G.; Van Isacker, P.(GANIL, CEA/DSM–CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5, France)

    2003-01-01

    A three-configuration mixing calculation is performed in the context of the interacting boson model with the aim to describe recently observed collective bands built on low-lying $0^+$ states in neutron-deficient lead isotopes. The configurations that are included correspond to the regular, spherical states as well as two-particle two-hole and four-particle four-hole excitations across the Z=82 shell gap.

  19. Lead isotope studies of the Guerrero composite terrane, west-central Mexico: implications for ore genesis

    Science.gov (United States)

    Potra, Adriana; Macfarlane, Andrew W.

    2014-01-01

    New thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry Pb isotope analyses of three Cenozoic ores from the La Verde porphyry copper deposit located in the Zihuatanejo-Huetamo subterrane of the Guerrero composite terrane are presented and the metal sources are evaluated. Lead isotope ratios of 3 Cenozoic ores from the El Malacate and La Esmeralda porphyry copper deposits located in the Zihuatanejo-Huetamo subterrane and of 14 ores from the Zimapan and La Negra skarn deposits from the adjoining Sierra Madre terrane are also presented to look for systematic differences in the lead isotope trends and ore metal sources among the proposed exotic tectonostratigraphic terranes of southern Mexico. Comparison among the isotopic signatures of ores from the Sierra Madre terrane and distinct subterranes of the Guerrero terrane supports the idea that there is no direct correlation between the distinct suspect terranes of Mexico and the isotopic signatures of the associated Cenozoic ores. Rather, these Pb isotope patterns are interpreted to reflect increasing crustal contribution to mantle-derived magmas as the arc advanced eastward onto a progressively thicker continental crust. The lead isotope trend observed in Cenozoic ores is not recognized in the ores from Mesozoic volcanogenic massive sulfide and sedimentary exhalative deposits. The Mesozoic ores formed prior to the amalgamation of the Guerrero composite terrane to the continental margin, which took place during the Late Cretaceous, in intraoceanic island arc and intracontinental marginal basin settings, while the Tertiary deposits formed after this event in a continental arc setting. Lead isotope ratios of the Mesozoic and Cenozoic ores appear to reflect these differences in tectonic setting of ore formation. Most Pb isotope values of ores from the La Verde deposit (206Pb/204Pb = 18.674-18.719) are less radiogenic than those of the host igneous rocks, but plot within the

  20. Lead isotopes in soils near five historic American lead smelters and refineries.

    Science.gov (United States)

    Rabinowitz, Michael B

    2005-06-15

    This survey of soil lead in the vicinity of old industrial sites examines how the stable isotope patterns vary among the sites according to the sources of the lead ore processed at each site. Lead smelters and refineries, which closed down decades ago, are the basis of this investigation. Samples were taken from near five old factory sites in Collinsville and Alton (Illinois), Ponderay (Idaho), East Chicago (Indiana) and Omaha (Nebraska). Historical records were searched for accounts of the sources of the lead. Lead concentrations were measured by atomic absorption flame spectrophotometry, and stable isotopic analysis was done by plasma ionization mass spectrometry. At every site visited, remnants of the old factories, in terms of soil lead pollution, could be found. In spite of potential complications of varying smelter feedstock sourced from mines of different geological age, it was possible to match the isotopic patterns in the soils with the documented sources of the ores. The Collinsville and Alton sites resembled Missouri lead. The Ponderay value was higher than major Bunker Hill, Idaho deposits, but closer to the minor, nearby Oreille County, Washington ores. Mostly Utah ore was used in East Chicago. The Omaha soil reflects lead from Mexico, Colorado and Montana.

  1. Lead isotopes and trace metals in dust at Yucca Mountain

    Science.gov (United States)

    Kwak, Loretta; Neymark, Leonid A.; Peterman, Zell E.

    2008-01-01

    Lead (Pb)-isotope compositions and trace-metal concentrations were determined for samples of dust collected from underground and surface locations at and near the proposed radioactive waste repository at Yucca Mountain, Nevada. Rare earth element concentrations in the dust samples from the underground tunnels are similar to those in wholerock samples of the repository host rocks (Miocene Tiva Canyon Tuff and Topopah Spring Tuff), supporting interpretation that the subsurface dust is mainly composed of rock comminuted during tunnel construction. Other trace metals (arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, antimony, thallium, and zinc) are variably enriched in the subsurface dust samples relative to the average concentrations in the host rocks. Average concentrations of arsenic and lead in dust samples, high concentrations of which can cause corrosion of waste canisters, have enrichment factors from 1.2 to 1.6 and are insignificant relative to the range of concentrations for these metals observed in the host rock samples. Most dust samples from surface sites also are enriched in many of these trace metals relative to average repository host rocks. At least some of these enrichments may be artifacts of sampling. Plotted on a 208Pb/206Pb-207Pb/206Pb graph, Pb-isotope compositions of dust samples from underground sites form a mixing line extending from host-rock Pb-isotope compositions towards compositions of many of the dust samples from surface sites; however, combined Pb concentration and isotope data indicate the presence of a Pbenriched component in the subsurface dust that is not derived from host rock or surface dust and may derive from anthropogenic materials introduced into the underground environment.

  2. Laser photochemical lead isotopes separation for harmless nuclear power engineering

    Science.gov (United States)

    Bokhan, P. A.; Fateev, N. V.; Kim, V. A.; Zakrevsky, D. E.

    2016-09-01

    The collisional quenching of the metastable 3 P 1,2 and 1 D 2 lead atoms is studied experimentally in the gas flow of the lead atoms, reagent-molecules and a carrier gas Ar. The experimental parameters were similar to the conditions that are required in the operation of the experimental setup for photochemical isotope separation. Excited atoms are generated under electron impact conditions created by a gas glow discharge through the mixture of gases and monitored photoelectrically by attenuation of atomic resonance radiation from hollow cathode 208Pb lamp. The decay of the excited atoms has been studied in the presence various molecules and total cross section data are reported. The flow tube measurements has allowed to separate the physical and chemical quenching channels and measure the rates of the chemical reaction excited lead with N2O, CH2Cl2, SF6 and CuBr molecules. These results are discussed in the prospects of the obtaining isotopically modified lead as a promising coolant in the reactors on the fast-neutron.

  3. Australian atmospheric lead deposition reconstructed using lead concentrations and isotopic compositions of archival lichen and fungi.

    Science.gov (United States)

    Wu, Liqin; Taylor, Mark Patrick; Handley, Heather K; Wu, Michael

    2016-01-01

    Lead concentrations and their isotopic compositions were measured in lichen genera Cladonia and Usnea and fungi genus Trametes from the Greater Sydney region (New South Wales, Australia) that had been collected and archived over the past 120 years. The median lead contents were elevated in lichens and fungi prior to the introduction of leaded petrol (Cladonia 12.5 mg/kg; Usnea 15.6 mg/kg; Trametes 1.85 mg/kg) corresponding to early industrial development. During the use of leaded petrol for automobiles in Australia from 1932 to 2002, total median lead concentrations rose: Cladonia 18.8 mg/kg; Usnea 21.5 mg/kg; Trametes 4.3 mg/kg. Following the cessation of leaded petrol use, median total lead concentrations decreased sharply in the 2000s: Cladonia 4.8 mg/kg; Usnea 1.7 mg/kg. The lichen and fungi isotopic compositions reveal a significant decrease in (206)Pb/(207)Pb values from the end of 19th century to the 1970s. The following decades were characterised by lower allowable levels of lead additive in fuel and the introduction of unleaded petrol in 1985. The environmental response to these regulatory changes was that lichen and fungi (206)Pb/(207)Pb values increased, particularly from 1995 onwards. Although the lead isotope ratios of lichens continued to increase in the 2000s they do not return to pre-leaded petrol values. This demonstrates that historic leaded petrol emissions, inter alia other sources, remain a persistent source of anthropogenic contamination in the Greater Sydney region.

  4. Ancient bronze coins from Mediterranean basin: LAMQS potentiality for lead isotopes comparative analysis with former mineral

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: Lorenzo.Torrisi@unime.it [Department of Physics Science - MIFT, Messina University, V.le F.S. d’Alcontres 31, 98166 S. Agata, Messina (Italy); Italiano, A. [INFN, Sezione di Catania, Gruppo collegato di Messina (Italy); Torrisi, A. [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw (Poland)

    2016-11-30

    Highlights: • Surface and bulk compositional elements in ancient bronze coins were investigated using XRF analysis. • Lead stable isotope {sup 204}Pb, {sup 206}Pb, {sup 207}Pb and {sup 208}Pb were measured in ancient coins with LAMQS analysis. • Lead ratios {sup 208}Pb/{sup 206}Pb and {sup 207}Pb/{sup 206}Pb, measured by LAMQS, were compared with Brettscaife.net geological database relative to the minerals in different mines of Mediterranean basin. • Bronze coins were correlated to possible ancient mining sites of minerals from which lead was extracted. - Abstract: Bronze coins coming from the area of the Mediterranean basin, dated back the II–X Cent. A.D., were analyzed using different physical analytical techniques. Characteristic X-ray fluorescence was used with electrons and photons, in order to investigate the elemental composition of both the surface layers and bulk. Moreover, the quadrupole mass spectrometry coupled to laser ablation (LAMQS technique) in high vacuum was used to analyse typical material compounds from surface contamination. Mass spectrometry, at high resolution and sensitivity, extended up to 300 amu, allowed measuring the {sup 208}Pb/{sup 206}Pb and {sup 207}Pb/{sup 206}Pb isotopic ratios into the coins. Quantitative relative analyses of these isotopic ratios identify the coin composition such as a “fingerprint” depending on the mineral used to extract the lead. Isotopic ratios in coins can be compared to those of the possible minerals used to produce the bronze alloy. A comparison between the measured isotope ratios in the analyzed coins and the literature database, related to the mineral containing Pb as a function of its geological and geophysical extraction mine, is presented. The analysis, restricted to old coins and the mines of the Mediterranean basin, indicates a possible correlation between the coin compositions and the possible geological sites of the extracted mineral.

  5. Heavy metals and lead isotopes in sdB stars

    CERN Document Server

    O'Toole, S

    2006-01-01

    We present a detailed abundance analysis of high-resolution ultraviolet echelle spectra of five subdwarf B stars obtained with HST-STIS The goal of our observations was to test the hypothesis that pulsations in sdBs are correlated to the surface abundances of iron-group elements. We study two pulsators and three non-pulsators and determined abundances for 25 elements including the iron group and even heavier elements such as tin and lead using LTE spectrum synthesis techniques. We find strong enrichments of heavy elements up to 2.9dex with respect to solar which are probably caused by atomic diffusion processes. No clear-cut correlation between pulsations and metal abundances becomes apparent. Abundances for lead isotopes are derived from very high resolution spectra using an UV line of triply ionised lead. As Pb terminates the s-process sequence Pb isotopic abundance ratios yield important constraints. It is very difficult to measure them in hot stars. For the first time we were able to measure them in two s...

  6. Lead contamination and transfer in urban environmental compartments analyzed by lead levels and isotopic compositions.

    Science.gov (United States)

    Hu, Xin; Sun, Yuanyuan; Ding, Zhuhong; Zhang, Yun; Wu, Jichun; Lian, Hongzhen; Wang, Tijian

    2014-04-01

    Lead levels and isotopic compositions in atmospheric particles (TSP and PM2.5), street dust and surface soil collected from Nanjing, a mega city in China, were analyzed to investigate the contamination and the transfer of lead in urban environmental compartments. The lead contents in TSP and PM2.5 are significantly higher than them in the surface soil and street dust (p atmospheric particles. The plots of (206)Pb/(207)Pb vs.(208)Pb/(206)Pb and (206)Pb/(207)Pb vs. 1/Pb imply that the street dust and atmospheric particles (TSP and PM2.5) have very similar lead sources. Coal emissions and smelting activities may be the important lead sources for street dust and atmospheric particles (TSP and PM2.5), while the deposition of airborne lead is an important lead source for urban surface soil.

  7. DEVELOPMENT OF LEAD SLOWING DOWN SPECTROMETER FOR ISOTOPIC FISSILE ASSAY

    Directory of Open Access Journals (Sweden)

    SANG JOON AHN

    2014-12-01

    Full Text Available A lead slowing down spectrometer (LSDS is under development for analysis of isotopic fissile material contents in pyro-processed material, or spent fuel. Many current commercial fissile assay technologies have a limitation in accurate and direct assay of fissile content. However, LSDS is very sensitive in distinguishing fissile fission signals from each isotope. A neutron spectrum analysis was conducted in the spectrometer and the energy resolution was investigated from 0.1eV to 100keV. The spectrum was well shaped in the slowing down energy. The resolution was enough to obtain each fissile from 0.2eV to 1keV. The detector existence in the lead will disturb the source neutron spectrum. It causes a change in resolution and peak amplitude. The intense source neutron production was designed for ∼E12 n's/sec to overcome spent fuel background. The detection sensitivity of U238 and Th232 fission chamber was investigated. The first and second layer detectors increase detection efficiency. Thorium also has a threshold property to detect the fast fission neutrons from fissile fission. However, the detection of Th232 is about 76% of that of U238. A linear detection model was set up over the slowing down neutron energy to obtain each fissile material content. The isotopic fissile assay using LSDS is applicable for the optimum design of spent fuel storage to maximize burnup credit and quality assurance of the recycled nuclear material for safety and economics. LSDS technology will contribute to the transparency and credibility of pyro-process using spent fuel, as internationally demanded.

  8. Lead isotopic evidence for selective uptake of radium in illite

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, H.; Horie, K. [Department of Earth and Planetary Systems Science, Hiroshima University Higashi-Hiroshima 739-8526 (Japan); Gauthier-Lafaye, F. [Centre de Geochimie de la Surface, UMR7517-CNRS-ULP, 67084 Strasbourg (France)

    2005-07-01

    Full text of publication follows: Radium has no stable isotopes. {sup 226}Ra having the longest half-life (T{sub 1/2} = 1600 year) among radium radioisotopes exists as a precursor of decay product from {sup 238}U in nature, and finally decays to the stable isotope {sup 206}Pb. Long-lived nuclides such as {sup 226}Ra may be profoundly fractionated from their parents in association with intense geochemical events in the terrestrial environments. Enrichment of Ra resulted from vegetation cycle and selective uptake into clay minerals has been reported [1,2]. It is of particular interest to understand the geochemical behaviors of Ra from the viewpoint of long-termed repository safety of radio-nuclear waste. We report here geochemical evidence of selective uptake of Ra ({sup 226}Ra) into clay minerals studied from the Pb isotopic compositions. The sample from sandstone layer at underground drift close to natural reactor zone 13 at the Oklo uranium deposits, Gabon. Several tiny illite grains sized about 100 {mu}m were found in fine calcite veins with 0.1 to 2 mm width in quartz matrix texture. Isotopic analyses of Pb and some related elements (U, Rb, Sr, Cs and Ba) in individual minerals were carried out by a Sensitive High Resolution Ion Microprobe (SHRIMP) at Hiroshima University. The Pb isotopic data of quartz and calcite in the sample provide the geochronological information corresponding to the formation of 2.15 billion year-old basement rocks and the occurrence of later hydrothermal activity in this region at 0.88 billion years, respectively. On the other hand, illite shows high enrichment of {sup 206}Pb, which cannot be explained simply from normal U decays. {sup 206}Po-enriched illite grains also show a strong enrichment of Ba. Such an enrichment of Ba is not observed in the neighboring minerals of illite grains. Considering that Ba has been used as a chemical tracer of {sup 226}Ra because of the chemical similarities between Ba and Ra, our result strongly

  9. A lead isotopic assessment of tree bark as a biomonitor of contemporary atmospheric lead

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, Gavin J. [School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland (United Kingdom); Farmer, John G. [School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JN, Scotland (United Kingdom)], E-mail: J.G.Farmer@ed.ac.uk

    2007-12-15

    The outermost bark layer of trees, predominantly Scots pine (Pinus sylvestris), was sampled at 82 non-urban locations from six arbitrarily designated areas (Northwest, Northeast, Central Highlands, Central and East, Central and Southwest, Southeast), throughout Scotland during 2002-2003 and analysed for lead concentration and stable lead isotopes by flame atomic absorption spectrometry (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The mean lead concentration and mean {sup 206}Pb/{sup 207}Pb ratio ({+-} 1 standard deviation, SD) for bark samples from the areas were as follows: Northwest (8.0 mg kg{sup -1}, 1.121 {+-} 0.014, n = 17), Northeast (8.9 mg kg{sup -1}, 1.117 {+-} 0.012, n = 12), Central Highlands (11.3 mg kg{sup -1}, 1.130 {+-} 0.010, n = 11), Central and East (35.3 mg kg{sup -1}, 1.120 {+-} 0.007, n = 10), Central and Southwest (20.6 mg kg{sup -1}, 1.125 {+-} 0.018, n = 22) and Southeast (34.4 mg kg{sup -1}, 1.120 {+-} 0.005, n = 10), with an overall mean lead concentration of 18.5 mg kg{sup -1} (range 0.6-146 mg kg{sup -1}, median 8.4 mg kg{sup -1}) and an overall mean {sup 206}Pb/{sup 207}Pb ratio of 1.122 {+-} 0.014 (range 1.089-1.168, median 1.122). The overall mean {sup 206}Pb/{sup 207}Pb ratio for bark was therefore significantly lower (p < 0.01, t test) than the mean atmospheric {sup 206}Pb/{sup 207}Pb ratio of 1.154 {+-} 0.006 (range 1.144-1.167, n = 50) and 1.154 {+-} 0.010 (range 1.134-1.171, n = 26) as determined in rainwater collected routinely at Glensaugh, Central Highlands, during 2002 and 2003, respectively. The bark {sup 206}Pb/{sup 207}Pb values, 90% of which lay between 1.10 and 1.14, were more akin to those recorded for the atmosphere (via rainwater, atmospheric particulates, moss, etc.) at various locations throughout Scotland during the 1990s, a decade over which the use of leaded petrol (mean {sup 206}Pb/{sup 207}Pb ratio = 1.076 {+-} 0.011) declined markedly before its complete withdrawal in 2000

  10. Modern Freshwater Microbialites of Cuatro Ciénegas, Mexico. I: Metagenomic and Stable Isotopic Analyses to Assess Microbial Community Structure and Function

    Science.gov (United States)

    Breitbart, M.; Hollander, D.; Nitti, A.; van Mooy, B.; Siefert, J.; Souza, V.

    2010-04-01

    This study utilized metagenomic and stable isotopic analyses to examine the microorganisms and chemical processes leading to carbonate precipitation in the actively-accreting freshwater microbialites from Rio Mesquites in Cuatro Ciénegas, Mexico.

  11. Ancient bronze coins from Mediterranean basin: LAMQS potentiality for lead isotopes comparative analysis with former mineral

    Science.gov (United States)

    Torrisi, L.; Italiano, A.; Torrisi, A.

    2016-11-01

    Bronze coins coming from the area of the Mediterranean basin, dated back the II-X Cent. A.D., were analyzed using different physical analytical techniques. Characteristic X-ray fluorescence was used with electrons and photons, in order to investigate the elemental composition of both the surface layers and bulk. Moreover, the quadrupole mass spectrometry coupled to laser ablation (LAMQS technique) in high vacuum was used to analyse typical material compounds from surface contamination. Mass spectrometry, at high resolution and sensitivity, extended up to 300 amu, allowed measuring the 208Pb/206Pb and 207Pb/206Pb isotopic ratios into the coins. Quantitative relative analyses of these isotopic ratios identify the coin composition such as a "fingerprint" depending on the mineral used to extract the lead. Isotopic ratios in coins can be compared to those of the possible minerals used to produce the bronze alloy. A comparison between the measured isotope ratios in the analyzed coins and the literature database, related to the mineral containing Pb as a function of its geological and geophysical extraction mine, is presented. The analysis, restricted to old coins and the mines of the Mediterranean basin, indicates a possible correlation between the coin compositions and the possible geological sites of the extracted mineral.

  12. Variations in lead isotopic abundances in Sprague-Dawley rat tissues: possible reason of formation.

    Directory of Open Access Journals (Sweden)

    Duojian Liu

    Full Text Available It has been reported in previous research that the lead isotopic composition of blood, urine and feces samples statistically differed from the given lead sources in Sprague-Dawley (SD rats. However, the reason for this phenomenon is still unclear. An animal experiment was performed to investigate the lead isotope fractionation in diverse biological samples (i.e., lungs, liver, kidneys, bone and to explore the possible reasons. SD rats were intratracheally instilled with lead acetate at the concentrations of 0, 0.02, 0.2, and 2 mg/kg body weight. Biological samples were collected for lead isotope analysis using an inductively coupled plasma mass spectrometry (ICP-MS. Significant differences are observed in lead isotope abundances among the diverse biological samples. The lead isotope abundances ((206Pb, (207Pb and (208Pb in diverse biological samples show different degrees and directions of departure from the given lead source. The results suggest that differences in enrichment or depletion capacity for each lead isotope in the various tissues might lead to the variation in lead isotopic abundances in tissues. Moreover, a nonlinear relationship between the blood lead level and the lead isotope abundances in liver and bone is observed. When the whole-blood level is higher than 50 ng/mL, the lead isotopic compositions of biological samples tend to be the same. Thus, the data support the speculation of a fractionation functional threshold.

  13. Lead isotope composition of Central American volcanoes: Influence of the Galapagos plume

    Science.gov (United States)

    Feigenson, Mark D.; Carr, Michael J.; Maharaj, Susan V.; Juliano, Scott; Bolge, Louise L.

    2004-06-01

    Lead isotopic analyses of lavas from Central America, both along and behind the volcanic arc, help to clarify source components in the mantle wedge. Analysis of previous Pb isotopic data had implied that little or no marine sediment lead was added to the Central American source region, as all samples fell within the MORB field, in contrast to other information (e.g., Ba/La, 10Be, 87Sr/86Sr) that indicated a high subduction component. The data presented here include several analyses of local marine sediment, showing it to be exceptionally unradiogenic in Pb and thus permitting high sediment contributions to the mantle source region without significant changes in Pb isotopes. Combined Pb-Nd and Pb-Sr isotopic diagrams clearly illustrate the influence of crustal contamination for samples from Guatemala and Honduras, and of subducted sediment for all lavas of the volcanic front. Samples collected behind the volcanic front are derived from mixing between enriched and depleted mantle sources, and in central Costa Rica (extending to the back arc) overlap Pb, Sr and Nd isotope values for both Cocos Island and some components of the Galapagos hot spot. The restricted geographical occurrence of the enriched mantle signature in Central America, coupled with the persistence of the signal well into the back arc region, imply that these lavas are sampling Galapagos plume-influenced mantle. The presence of this plume component beneath southern Central America and extending to the northeast beneath the Caribbean confirms a Galapagos hot spot origin for this part of Caribbean Plate.

  14. Analysis and separation of boron isotopes; Analyse et separation des isotopes du bore

    Energy Technology Data Exchange (ETDEWEB)

    Perie, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-11-01

    . Ces resultats ont permis d'etablir un mode operatoire pour l'analyse de traces de-bore,par dilution isotopique. Par ailleurs, les besoins en bore-10 de l'industrie nucleaire justifient la mise au point de procedes de separation des isotopes du bore. Un effet isotopique notable a ete mis en evidence dans la reaction d'echange chimique entre le borate de methyle et un sel borique en solution. Dans le cas de l'echange borate de methyle - borate de sodium, le facteur de separation elementaire {alpha}: {alpha}=(({sup 11}B/{sup 10}B)vap.)/(({sup 11}B/{sup 10}B)liq.)=1.03{sub 3}. Cet effet elementaire eleve a ete multiplie dans une colonne de distillation dans laquelle le probleme de la regeneration des reactifs a ete resolu. Une variante de ce procede a ete etudiee, en remplacant le borate alcalin par un borate de base volatile; ici la diethylamine ({alpha}=1,02{sub 5} en milieu hydromethanolique a 2,2 pour cent d'eau). (auteur)

  15. Identification of historical lead sources in roof dusts and recent lake sediments from an industrialized area: indications from lead isotopes.

    Science.gov (United States)

    Chiaradia, M; Chenhall, B E; Depers, A M; Gulson, B L; Jones, B G

    1997-10-20

    X-ray fluorescence and stable lead (Pb) isotopic analyses have been undertaken on dusts, known from microscopic investigation to contain significant quantities of industrially- and urban-derived particulate matter, present in the roof cavities of houses in the Illawarra region (N.S.W., Australia), with the objective of examining the historic record of Pb pollution. All investigated houses contained in excess of 250 micrograms g-1 Pb, with dwellings close to a copper smelter, in a large industrial complex including a major steelworks, containing higher (> 2500 micrograms g-1) Pb concentrations. The isotopic composition in the dusts, expressed here as 206Pb/204Pb, is relatively constant at 17.0, irrespective of dwelling age or distance from the industrial complex. Contamination of the dusts by Pb sourced from paint cannot explain the isotopic uniformity of the dust samples. Isotopic modelling indicates that the dusts contain Pb derived from the copper smelter, gasoline-air Pb and a minor contribution from coal-utilising sources. Lead loading was also investigated in the adjacent lagoon, which acts as a natural sink for particulate matter in the Illawarra region. Isotopic data and modelling indicate that one natural and four anthropogenic sources contribute to the Pb burden of this lagoon. The natural source consists of Permian rocks cropping out in the catchment area which have a 206Pb/204Pb of approximately 18.7. The suggested anthropogenic sources are an old disbanded base-metal (Pb) smelter (206Pb/204Pb approximately 16.2-16.3), the copper smelter (206Pb/204Pb approximately 17.9), gasoline-air derived Pb (206Pb/204Pb approximately 16.4-16.5) and industries utilising coal, for example the recently closed thermal coal-fired power station (206Pb/204Pb approximately 18.9). The relative contributions of the base-metal (mainly lead) smelter and gasoline-air Pb in the sediment can only be partly assessed due to the isotopic similarity of these sources. Likewise the

  16. Shergottite Lead Isotope Signature in Chassigny and the Nakhlites

    Science.gov (United States)

    Jones, J. H.; Simon, J. I.

    2017-01-01

    The nakhlites/chassignites and the shergottites represent two differing suites of basaltic martian meteorites. The shergottites have ages less than or equal to 0.6 Ga and a large range of initial Sr-/Sr-86 and epsilon (Nd-143) ratios. Conversely, the nakhlites and chassignites cluster at 1.3-1.4 Ga and have a limited range of initial Sr-87/Sr-86 and epsilon (Nd-143). More importantly, the shergottites have epsilon (W-182) less than 1, whereas the nakhlites and chassignites have epsilon (W-182) approximately 3. This latter observation precludes the extraction of both meteorite groups from a single source region. However, recent Pb isotopic analyses indicate that there may have been interaction between shergottite and nakhlite/chassignite Pb reservoirs.Pb Analyses of Chassigny: Two different studies haveinvestigated 207Pb/204Pb vs. 206Pb/204Pb in Chassigny: (i)TIMS bulk-rock analyses of successive leaches and theirresidue [3]; and (ii) SIMS analysis of individual minerals[4]. The bulk-rock analyses fall along a regression of SIMSplagioclase analyses that define an errorchron that is olderthan the Solar System (4.61±0.1 Ga); i.e., these define amixing line between Chassigny’s principal Pb isotopic components(Fig. 1). Augites and olivines in Chassingy (notshown) also fall along or near the plagioclase regression [4].This agreement indicates that the whole-rock leachateslikely measure indigenous, martian Pb, not terrestrial contamination[5]. SIMS analyses of K-spars and sulfides definea separate, sub-parallel trend having higher 207Pb/206Pbvalues ([4]; Fig. 1). The good agreement between the bulkrockanalyses and the SIMS analyses of plagioclases alsoindicates that the Pb in the K-spars and sulfides cannot be amajor component of Chassigny.The depleted reservoir sampled by Chassigny plagioclaseis not the same as the solar system initial (PAT) andrequires a multi-stage origin. Here we show a two-stagemodel (Fig. 1) with a 238U/204Pb (µ) of 0.5 for 4.5-2.4 Gaand a µ of

  17. Lead and zinc dust depositions from ore trains characterised using lead isotopic compositions.

    Science.gov (United States)

    Kristensen, L J; Taylor, M P; Morrison, A L

    2015-03-01

    This study investigates an unusual source of environmental lead contamination - the emission and deposition of lead and zinc concentrates along train lines into and out of Australia's oldest silver-lead-zinc mine at Broken Hill, Australia. Transport of lead and zinc ore concentrates from the Broken Hill mines has occurred for more than 125 years, during which time the majority was moved in uncovered rail wagons. A significant amount of ore was lost to the adjoining environments, resulting in soil immediately adjacent to train lines elevated with concentrations of lead (695 mg kg(-1)) and zinc (2230 mg kg(-1)). Concentrations of lead and zinc decreased away from the train line and also with depth shown in soil profiles. Lead isotopic compositions demonstrated the soil lead contained Broken Hill ore in increasing percentages closer to the train line, with up to 97% apportioned to the mined Broken Hill ore body. SEM examination showed ceiling dusts collected from houses along the train line were composed of unweathered galena particles, characteristic of the concentrate transported in the rail wagons. The loss of ore from the uncovered wagons has significantly extended the environmental footprint of contamination from local mining operations over an area extending hundreds of kilometres along each of the three train lines.

  18. Effects of preservatives on stable isotope analyses of four marine species

    Science.gov (United States)

    Carabel, Sirka; Verísimo, Patricia; Freire, Juan

    2009-04-01

    The aim of the present study is to quantify the effect of formalin-ethanol preservation on the carbon and nitrogen stable isotope signatures of four taxonomical groups of marine species ( Himanthalia elongata, Anemonia sulcata, Mytilus galloprovincialis and Patella vulgata). To examine temporal changes in the effects of preservation and to determine if preservation induced predictable shifts in δ13C and δ15N signatures, repeated analyses were carried out after 6, 12 and 24 months of preservation. Data from our study showed highly variable effects of the formalin-ethanol preservation on carbon and nitrogen isotope signatures between species. The use of a general correction factor was not possible, or else it should be species-specific. Differences in nitrogen isotopic values between preserved and unpreserved samples were minor compared to the assumed enrichment between trophic levels. The combined use of data from preserved and unpreserved samples could lead to biases in the estimation of the trophic level of organisms. Changes that preservatives caused in carbon values were variable between species and not always small enough to be ignored. So the use of data from preserved samples could change the interpretation of the mixing models used to determine the importance of multiple sources of carbon. In order to elucidate the effects that preservatives have in other species, further studies will be necessary.

  19. Metallogeny and lead isotope data from the Oslo Paleorift

    Science.gov (United States)

    Bjørlykke, A.; Ihlen, P. M.; Olerud, S.

    1990-06-01

    The Permian Oslo Paleorift, situated at the southwestern margin of the Baltic shield, includes the Oslo Region and its southward extension under Skagerak. The exposed part of the paleorift comprises two half-grabens (Vestfold and Akershus graben segments) filled with Permian sediments, volcanics and intrusive rocks as well as Cambrc-Silurian sedimentary rocks. The evolution of the Oslo Rift can be divided into a rifting stage, a caldera stage and a batholith stage. The rifting stage is characterized by weak mineralization of native copper in basalts. The caldera stage includes Fe-Ti cumulates in subvolcanic layered alkali gabbros, Nb-REE disseminations in aphyric trachytes, and epigenetic Mo-mineralizations. The batholith stage includes porphyry and intraplutonic vein deposits of Mo and contact metasomatic deposits of Fe, W, Mo, Be, Zn, Pb, Cu, Bi, As and F. Along the rift margin in Precambrian gneisses and amphibolites there are vein deposits of Fe-oxides, base metals and native silver. The relationship between the rift margin deposits and the evolution of the rift is still unclear, but many deposits are spatially related to Permian dolerite dykes. Lead isotope data from hydrothermal deposits in the Oslo Rift fall into two main groups. The first group comprises the rift margin deposits. They are very radiogenic and reflect an upper crustal source for the metals. The source of the silver deposits generally has a lower μ-value and a higher w- value than the base metal deposits. The rift margin deposits are therefore not a product of metal zonation from a single hydrothermal solution. The second group comprises deposits associated with granitic intrusions in the Oslo Graben and reflects a lower to intermediate crustal source for the metals. Deposits in the Vestfold graben segment are generally more radiogenic than deposits in the Akershus graben segment and this difference may be explained by a small contribution of highly radiogenic lead from underlying Precambrian

  20. Identification of sources of lead exposure in French children by lead isotope analysis: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Lucas Jean-Paul

    2011-08-01

    Full Text Available Abstract Background The amount of lead in the environment has decreased significantly in recent years, and so did exposure. However, there is no known safe exposure level and, therefore, the exposure of children to lead, although low, remains a major public health issue. With the lower levels of exposure, it is becoming more difficult to identify lead sources and new approaches may be required for preventive action. This study assessed the usefulness of lead isotope ratios for identifying sources of lead using data from a nationwide sample of French children aged from six months to six years with blood lead levels ≥25 μg/L. Methods Blood samples were taken from 125 children, representing about 600,000 French children; environmental samples were taken from their homes and personal information was collected. Lead isotope ratios were determined using quadrupole ICP-MS (inductively coupled plasma - mass spectrometry and the isotopic signatures of potential sources of exposure were matched with those of blood in order to identify the most likely sources. Results In addition to the interpretation of lead concentrations, lead isotope ratios were potentially of use for 57% of children aged from six months to six years with blood lead level ≥ 25 μg/L (7% of overall children in France, about 332,000 children, with at least one potential source of lead and sufficiently well discriminated lead isotope ratios. Lead isotope ratios revealed a single suspected source of exposure for 32% of the subjects and were able to eliminate at least one unlikely source of exposure for 30% of the children. Conclusions In France, lead isotope ratios could provide valuable additional information in about a third of routine environmental investigations.

  1. Constraining recent lead pollution sources in the North Pacific using ice core stable lead isotopes

    Science.gov (United States)

    Gross, B. H.; Kreutz, K. J.; Osterberg, E. C.; McConnell, J. R.; Handley, M.; Wake, C. P.; Yalcin, K.

    2012-08-01

    Trends and sources of lead (Pb) aerosol pollution in the North Pacific rim of North America from 1850 to 2001 are investigated using a high-resolution (subannual to annual) ice core record recovered from Eclipse Icefield (3017 masl; St. Elias Mountains, Canada). Beginning in the early 1940s, increasing Pb concentration at Eclipse Icefield occurs coevally with anthropogenic Pb deposition in central Greenland, suggesting that North American Pb pollution may have been in part or wholly responsible in both regions. Isotopic ratios (208Pb/207Pb and 206Pb/207Pb) from 1970 to 2001 confirm that a portion of the Pb deposited at Eclipse Icefield is anthropogenic, and that it represents a variable mixture of East Asian (Chinese and Japanese) emissions transported eastward across the Pacific Ocean and a North American component resulting from transient meridional atmospheric flow. Based on comparison with source material Pb isotope ratios, Chinese and North American coal combustion have likely been the primary sources of Eclipse Icefield Pb over the 1970-2001 time period. The Eclipse Icefield Pb isotope composition also implies that the North Pacific mid-troposphere is not directly impacted by transpolar atmospheric flow from Europe. Annually averaged Pb concentrations in the Eclipse Icefield ice core record show no long-term trend during 1970-2001; however, increasing208Pb/207Pb and decreasing 206Pb/207Pb ratios reflect the progressive East Asian industrialization and increase in Asian pollutant outflow. The post-1970 decrease in North American Pb emissions is likely necessary to explain the Eclipse Icefield Pb concentration time series. When compared with low (lichen) and high (Mt. Logan ice core) elevation Pb data, the Eclipse ice core record suggests a gradual increase in pollutant deposition and stronger trans-Pacific Asian contribution with rising elevation in the mountains of the North Pacific rim.

  2. Using Lead Concentrations and Stable Lead Isotope Ratios to Identify Contamination Events in Alluvial Soils

    Directory of Open Access Journals (Sweden)

    Diane Saint-Laurent

    2010-01-01

    Full Text Available Soils contaminated with hydrocarbons (C10–C50, polycyclic aromatic hydrocarbons (PAHs, and other contaminants (e.g., As, Cd, Cu, Pb were recently discovered on the banks of the Saint-François and Massawippi rivers. Alluvial soils are contaminated over a distance of 100 kilometers, and the level of the contaminated-hydrocarbon layer in the soil profiles is among the highest at the Windsor and Richmond sites. Concentrations of lead and stable lead isotope ratios (204Pb/206Pb, 207Pb/206Pb, 208Pb/206Pb are also used to identify contamination events. The maximum and minimum values detected in soil profiles for arsenic, cadmium, and lead vary from 3.01 to 37.88 mg kg-1 (As, 0.11 to 0.81 mg kg-1 (Cd 12.32 to 149.13 mg kg-1 (Pb, respectively, while the 207Pb/206Pb isotopic ratio values are between 0.8545 and 0.8724 for all the profiles. The highest values of trace elements (As, Pb and Zn were detected in the hydrocarbon layer (C10–C50, most often located at the bottom of the profiles (160, 200, and 220 cm in depth. The various peaks recorded in the soils and the position of the profiles suggest that various contaminants were transported by the river on several occasions and infiltrated the soil matrix or deposited on floodplains during successive floods. Atmospheric particles which entered the river or deposited on riverbanks must also be considered as another source of pollution recorded in soils.

  3. Tracing the transport of anthropogenic lead in the atmosphere and in soils using isotopic ratios

    Science.gov (United States)

    Erel, Yigal; Veron, Alain; Halicz, Ludwik

    1997-11-01

    The isotopic composition of lead in aerosols and soils in Israel is used to characterize the sources of anthropogenic lead in the region, to ascertain the isotopic composition of natural, rock-derived lead in specific areas, and to determine rates of anthropogenic lead migration in soils. The isotopic composition of lead currently emitted from cars in Israel ( 206Pb /207Pb = 1.115 ± 2 ) is controlled by alkyl-lead produced in France and Germany. In addition to petrol-lead, two more sources of anthropogenic lead can be detected in sampled aerosols: the first one has low concentrations of lead (˜4 ng/m 3) and 206Pb /207Pb ˜ 1.157 , and is most likely lead, emitted in Turkey, that traveled across the eastern Mediterranean basin; the second type of aerosols contains a mixture of lead emitted in several countries including Turkey, Greece, and Ukraine ( 206Pb /207Pb value of 1.155-1.160; [Pb] ˜ 20-30 ng/m 3). Anthropogenic lead is more accessible for acid leaching than natural lead, therefore, it is more labile in the soil. The isotopic composition of lead in the acid-leached fraction of near-road soil profiles record the histor of alkyl-lead emission in the country. Based on changes in the isotopic composition of lead with soil depth, it is estimated that anthropogenic lead migrates into the soil at approximately 0.5 cm/y. A soil profile from a relatively remote area is less contaminated by anthropogenic lead and displays a different distribution of lead isotopic values with depth. The isotopic composition of lead suggests that natural lead in soils developed on carbonate bedrock is derived from clays, either from the rock-esidue (the clay fraction in the carbonate bedrock), or from airborne clay, but not from lead released from the carbonate fraction in the rock.

  4. Lead (Pb) Isotope Baselines for Studies of Ancient Human Migration and Trade in the Maya Region

    National Research Council Canada - National Science Library

    Sharpe, Ashley E; Kamenov, George D; Gilli, Adrian; Hodell, David A; Emery, Kitty F; Brenner, Mark; Krigbaum, John

    2016-01-01

    .... We analyzed 60 rock samples for lead isotope ratios and a representative subset of samples for lead, uranium, and thorium concentrations across the Maya region, including the Northern Lowlands...

  5. On isotopic analyses of Mihonoseki and other meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Shima, Masako [National Science Museum, Tokyo (Japan)

    1994-12-31

    In the last December, since a meteorite penetrated a house in Mihonoseki-machi, Yatsuka-gun, Simane-ken, Japan, many people aware how meteorites are important for the study of space science. First, the results of the isotopic studies on meteorites obtained so far are summarized. The Mihonoseki meteorite is valuable only because it has the possibility of detecting short life cosmogenic radioactive nuclides as its fall was informed shortly after the fall, though it is a normal chondrite without special feature. A part of the obtained {gamma} ray spectrograph of the Mihonoseki was compared visually with that of the Tahara meteorite which fell one and a half years ago, the Hashima meteorite which fell about 80 years ago and terrestrial rocks. The preliminary data are given together with the data of the chondrites that fell in Japan in the last 10 years. As for the Mihonoseki meteorite, 15 cosmic ray-produced radioactive nuclides with the half life from 2.44 days to 7.2 x 10{sup 5} years were measured. Also the isotopic ratio of rare gas elements was determined, and from these data, it is concluded that the Mihonoseki meteorite has been exposed to cosmic ray for a long age, and it was not subjected to heavy shock effect. (K.I.).

  6. Perspectives on land snails - sampling strategies for isotopic analyses

    Science.gov (United States)

    Kwiecien, Ola; Kalinowski, Annika; Kamp, Jessica; Pellmann, Anna

    2017-04-01

    Since the seminal works of Goodfriend (1992), several substantial studies confirmed a relation between the isotopic composition of land snail shells (d18O, d13C) and environmental parameters like precipitation amount, moisture source, temperature and vegetation type. This relation, however, is not straightforward and site dependent. The choice of sampling strategy (discrete or bulk sampling) and cleaning procedure (several methods can be used, but comparison of their effects in an individual shell has yet not been achieved) further complicate the shell analysis. The advantage of using snail shells as environmental archive lies in the snails' limited mobility, and therefore an intrinsic aptitude of recording local and site-specific conditions. Also, snail shells are often found at dated archaeological sites. An obvious drawback is that shell assemblages rarely make up a continuous record, and a single shell is only a snapshot of the environmental setting at a given time. Shells from archaeological sites might represent a dietary component and cooking would presumably alter the isotopic signature of aragonite material. Consequently, a proper sampling strategy is of great importance and should be adjusted to the scientific question. Here, we compare and contrast different sampling approaches using modern shells collected in Morocco, Spain and Germany. The bulk shell approach (fine-ground material) yields information on mean environmental parameters within the life span of analyzed individuals. However, despite homogenization, replicate measurements of bulk shell material returned results with a variability greater than analytical precision (up to 2‰ for d18O, and up to 1‰ for d13C), calling for caution analyzing only single individuals. Horizontal high-resolution sampling (single drill holes along growth lines) provides insights into the amplitude of seasonal variability, while vertical high-resolution sampling (multiple drill holes along the same growth line

  7. Historical record of lead accumulation and source in the tidal flat of Haizhou Bay, Yellow Sea: Insights from lead isotopes.

    Science.gov (United States)

    Zhang, Rui; Guan, Minglei; Shu, Yujie; Shen, Liya; Chen, Xixi; Zhang, Fan; Li, Tiegang

    2016-05-15

    In order to investigate the historical records of lead contamination and source in coastal region of Haizhou Bay, Yellow Sea, a sediment core was collected from tidal flat, dated by (210)Pb and (137)Cs. Lead and its stable isotopic ratios were determined. The profiles of enrichment factor (EF) and Pb isotope ratios showed increasing trend upward throughout the core, correlating closely with the experience of a rapid economic and industrial development of the catchment. According to Pb isotopic ratios, coal combustion emission mainly contributed to the Pb burden in sediments. Based on end-member model, coal combustion emission dominated anthropogenic Pb sources in recent decades contributing from 48% to 67% in sediment. And the contribution of leaded gasoline was lower than 20%. A stable increase of coal combustion source was found in sediment core, while the contribution of leaded gasoline had declined recently, with the phase-out of leaded gasoline in China.

  8. A lead isotopic study of the human bioaccessibility of lead in urban soils from Glasgow, Scotland

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, John G., E-mail: J.G.Farmer@ed.ac.uk [School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3JN, Scotland (United Kingdom); Broadway, Andrew [School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3JN, Scotland (United Kingdom); Cave, Mark R.; Wragg, Joanna [British Geological Survey, Keyworth, Nottingham NG12 5GG, England (United Kingdom); Fordyce, Fiona M. [British Geological Survey, Edinburgh, EH9 3LA, Scotland (United Kingdom); Graham, Margaret C.; Ngwenya, Bryne T. [School of GeoSciences, University of Edinburgh, Edinburgh, EH9 3JN, Scotland (United Kingdom); Bewley, Richard J.F. [URS Corporation Ltd, Manchester, M1 6HS, England (United Kingdom)

    2011-11-01

    The human bioaccessibility of lead (Pb) in Pb-contaminated soils from the Glasgow area was determined by the Unified Bioaccessibility Research Group of Europe (BARGE) Method (UBM), an in vitro physiologically based extraction scheme that mimics the chemical environment of the human gastrointestinal system and contains both stomach and intestine compartments. For 27 soils ranging in total Pb concentration from 126 to 2160 mg kg{sup -1} (median 539 mg kg{sup -1}), bioaccessibility as determined by the 'stomach' simulation (pH {approx} 1.5) was 46-1580 mg kg{sup -1}, equivalent to 23-77% (mean 52%) of soil total Pb concentration. The corresponding bioaccessibility data for the 'stomach + intestine' simulation (pH {approx} 6.3) were 6-623 mg kg{sup -1} and 2-42% (mean 22%) of soil Pb concentration. The soil {sup 206}Pb/{sup 207}Pb ratios ranged from 1.057 to 1.175. Three-isotope plots of {sup 208}Pb/{sup 206}Pb against {sup 206}Pb/{sup 207}Pb demonstrated that {sup 206}Pb/{sup 207}Pb ratios were intermediate between values for source end-member extremes of imported Australian Pb ore (1.04) - used in the manufacture of alkyl Pb compounds (1.06-1.10) formerly added to petrol - and indigenous Pb ores/coal (1.17-1.19). The {sup 206}Pb/{sup 207}Pb ratios of the UBM 'stomach' extracts were similar (< 0.01 difference) to those of the soil for 26 of the 27 samples (r = 0.993, p < 0.001) and lower in 24 of them. A slight preference for lower {sup 206}Pb/{sup 207}Pb ratio was discernible in the UBM. However, the source of Pb appeared to be less important in determining the extent of UBM-bioaccessible Pb than the overall soil total Pb concentration and the soil phases with which the Pb was associated. The significant phases identified in a subset of samples were carbonates, manganese oxides, iron-aluminium oxyhydroxides and clays. - Highlights: {yields} We determined the human bioaccessibility of Pb in urban soils by in vitro extraction. {yields} We

  9. The lead isotopic age of the Earth can be explained by core formation alone.

    Science.gov (United States)

    Wood, Bernard J; Halliday, Alex N

    2010-06-10

    The meaning of the age of the Earth defined by lead isotopes has long been unclear. Recently it has been proposed that the age of the Earth deduced from lead isotopes reflects volatile loss to space at the time of the Moon-forming giant impact rather than partitioning into metallic liquids during protracted core formation. Here we show that lead partitioning into liquid iron depends strongly on carbon content and that, given a content of approximately 0.2% carbon, experimental and isotopic data both provide evidence of strong partitioning of lead into the core throughout the Earth's accretion. Earlier conclusions that lead is weakly partitioned into iron arose from the use of carbon-saturated (about 5% C) iron alloys. The lead isotopic age of the Earth is therefore consistent with partitioning into the core and with no significant late losses of moderately volatile elements to space during the giant impact.

  10. Origin of the mysterious Yin-Shang bronzes in China indicated by lead isotopes

    Science.gov (United States)

    Sun, Wei-dong; Zhang, Li-peng; Guo, Jia; Li, Cong-ying; Jiang, Yu-hang; Zartman, Robert E.; Zhang, Zhao-feng

    2016-01-01

    Fine Yin-Shang bronzes containing lead with puzzlingly highly radiogenic isotopic compositions appeared suddenly in the alluvial plain of the Yellow River around 1400 BC. The Tongkuangyu copper deposit in central China is known to have lead isotopic compositions even more radiogenic and scattered than those of the Yin-Shang bronzes. Most of the Yin-Shang bronzes are tin-copper alloys with high lead contents. The low lead and tin concentrations, together with the less radiogenic lead isotopes of bronzes in an ancient smelting site nearby, however, exclude Tongkuangyu as the sole supplier of the Yin-Shang bronzes. Interestingly, tin ingots/prills and bronzes found in Africa also have highly radiogenic lead isotopes, but it remains mysterious as to how such African bronzes may have been transported to China. Nevertheless, these African bronzes are the only bronzes outside China so far reported that have lead isotopes similar to those of the Yin-Shang bronzes. All these radiogenic lead isotopes plot along ~2.0–2.5 Ga isochron lines, implying that deposits around Archean cratons are the most likely candidates for the sources. African cratons along the Nile and even micro-cratons in the Sahara desert may have similar lead signatures. These places were probably accessible by ancient civilizations, and thus are the most favorable suppliers of the bronzes. PMID:26988425

  11. Lead isotopic evidence for evolutionary changes in magma-crust interaction, Central Andes, southern Peru

    Science.gov (United States)

    Barreiro, Barbara A.; Clark, Alan H.

    1984-07-01

    Lead isotopic measurements were made on Andean igneous rocks of Jurassic to Recent age in Moquegua and Tacna Departments, southernmost Peru, to clarify the petrogenesis of the rocks and, in particular, to investigate the effect of crustal thickness on rock composition. This location in the Cordillera Occidental is ideal for such a study because the ca. 2 Ga Precambrian basement rocks (Arequipa massif) have a distinct Pb isotopic signature which is an excellent tracer of crustal interaction, and because geomorphological research has shown that the continental crust was here thickened drastically in the later Tertiary. Seven samples of quartz diorites and granodiorites from the Ilo and Toquepala intrusive complexes, and seven samples of Toquepala Group subaerial volcanics were analyzed for Pb isotopic compositions. The plutonic rocks range in age from Jurassic to Eocene; the volcanic rocks are all Late Cretaceous to Eocene. With one exception, the Pb isotopic ratios are in the ranges 206Pb/ 204Pb= 18.52-18.75, 207Pb/ 204Pb= 15.58-15.65, and 208Pb/ 204Pb= 38.53-38.74. The data reflect very little or no interaction with old continental material of the Arequipa massif type. Lead from four Miocene Huaylillas Formation ash-flow tuffs, two Pliocene Capillune Formation andesites and five Quaternary Barroso Group andesites has lower 206Pb/ 204Pb than that in the pre-Miocene rocks, but relatively high 207Pb/ 204Pb and 208Pb/ 204Pb ( 206Pb/ 204Pb= 18.16-18.30, 207Pb/ 204Pb= 15.55-15.63, 208Pb/ 204Pb= 38.45-38.90). Tilton and Barreiro [9] have shown that contamination by Arequipa massif granulites can explain the isotopic composition of the Barosso Group lavas, and the new data demonstrate that this effect is evident, to varying degrees, in all the analysed Neogene volcanic rocks. The initial incorporation of such basement material into the magma coincided with the Early Miocene uplift of this segment of the Cordillera Occidental [32], and thus with the creation of a thick

  12. Differentiating sources of dissolved lead in mine waters using lead isotope techniques, Sullivan Mine, British Columbia

    Science.gov (United States)

    Lepitre, M. E.; Allen, D. M.; Mortensen, J. K.; Gabites, J. E.

    2003-01-01

    This study investigates the use of Pb isotopes in acid rock drainage studies and outlines a protocol for sampling and analysis of dissolved Pb in mine waters. Groundwaters and surface waters were sampled at the Sullivan Mine, British Columbia, to quantify Pb isotope ratios and to identify possible sources of Pb in mine effluent and back groundwaters, respectively. The Sullivan Deposit is a sediment-hosted Fe-Pb-Zn massive sulphide deposit with a well-defined homogeneous Pb isotopic composition, which provided a suitable end-member for the isotopic study. The Pb isotopic compositions of water samples define a mixing line between the homogeneous Pb isotopic signature of the Sullivan Ore and at least one other more radiogenic end-member. This end-member may correspond to Pb in the host rocks (Aldridge Formation), Pb from aerosols that have infiltrated the local surficial deposits with recharge, or Pb from the surficial deposits themselves. Further study is needed to more completely characterize the composition of potential isotopic end-members in the study area. The study demonstrates that different source regions for Pb have distinct and measurable isotopic compositions, which enable "fingerprinting" sources of Pb contamination that result from ore deposits or from other sources.

  13. Assessment of pollution aerosols sources above the Straits of Dover using lead isotope geochemistry.

    Science.gov (United States)

    Deboudt, K; Flament, P; Weis, D; Mennessier, J P; Maquinghen, P

    1999-09-15

    We assess the capability of lead isotopes to study the transport of pollution aerosols above the Straits of Dover by collecting atmospheric aerosols above the Eastern Channel and the Southern Bight of the North Sea. During the same period, we characterized the lead isotopic signature of the main industrial sources on the French coast near the Straits of Dover. Urban and automobile-derived aerosols were also collected. Due to the phasing out of lead in gasoline, the urban isotopic composition (206Pb/207Pb = 1.158 +/- 0.003) has become more radiogenic, although it is highly variable. On a regional scale, major industrial emissions have a well-defined isotopic composition (1.13 isotopic compositions, it can be shown that lead aerosols originating from eastern Europe have an isotopic signature (1.145 isotopic composition of west-European lead aerosols (1.111 < 206Pb/207Pb < 1.142). The influence of remote North American sources is suggested, with caution, due to uncertainties in meteorological calculations.

  14. Lead Isotope Constraints on the Sources of Ore Metals in SW Mexican Deposits

    Science.gov (United States)

    Potra, A.; Macfarlane, A. W.

    2007-12-01

    Lead isotope ratios from mineral deposits in southern Mexico increase with distance from the trench from 206Pb/204Pb values between 18.597 and 18.650 in the coastal area to values between 18.712 and 19.069 approximately 800 km east from the trench. This variation has been attributed to increasing assimilation of radiogenic lead from the crust with increasing distance from the trench. New sampling was undertaken in this area to provide a clearer picture of the potential sources of ore metals in this arc system, and also, if possible, to examine whether ore metal sources differ among the proposed tectonostratigraphic exotic terranes of southern Mexico. New TIMS lead isotope analyses are presented for samples from the metamorphic basement rocks of the Guerrero Terrane, the Late Cretaceous clastic sedimentary rocks from the Upper Mesozoic Assemblage, and for mid-Cretaceous igneous rocks, as well as for samples from the Oligocene La Verde, Esmeralda, and El Malacate copper prospects. Whole rock samples of schist from the Jurassic-Cretaceous Arteaga Complex and phyllite and slate from the Tierra Caliente Complex contain radiogenic lead relative to bulk earth models, with 206Pb/204Pb ranging from 18.981-19.256. These values are substantially more radiogenic than published values of analyses of metagabbro and charnockite from the Grenvillian-age Oaxaca Terrane. Sedimentary rocks (sandstones, siltstones, and marls) belonging to the Huetamo Sequence have 206Pb/204Pb values ranging between 18.630 to 18.998, close to the published data for the sediments from IPOD-DSDP Sites 487 and 488, Cocos Plate. Whole rock analyses of igneous rocks (granodiorite) collected from La Verde and El Malacate have 206Pb/204Pb ranging from 18.764 to 18.989, clustering between the fields represented by the sedimentary and the metamorphic rocks, suggesting assimilation of lead from these components. Ore samples from La Verde and Esmeralda have 206Pb/204Pb between 18.685 and 18.731 and plot within

  15. Lead isotopes and the origin of granulite and eclogite inclusions in deep-seated pipes

    Science.gov (United States)

    Lovering, J.F.; Tatsumoto, M.

    1968-01-01

    The isotopic composition of lead and the concentrations of lead, uranium, and thorium in Delegate basic pipes from Australia and in South African kimberlite pipes have been determined. The observed 238U/204Pb and observed 232Th/238U of eclogite inclusions in the pipes range from 2.9 to 18.7 and from 3.5 to 5.9, respectively. This result as well as the isotopic composition of lead suggests that the upper mantle is chemically heterogeneous with regard to the trace elements. Pyrochemically extracted leads from eclogite inclusions in the Delegate basic pipes and in a South African kimberlite pipe appear to be different in isotopic compositions from leads extracted from the host rock (matrix). These data are consistent with the hypothesis that the eclogitic inclusions in deep-seated pipes are of "accidental" origin and represent upper mantle materials caught up in the host materials during their intrusion. Lead extracted from a two-pyroxene granulite inclusion in one of the Delegate pipes has an isotopic composition indistinguishable from lead in the host rock. This observation is consistent either with a "cognate" origin for the granulite inclusion or with a modified "accidental" origin in which the isotopic composition of the original lead in the inclusion has been contaminated by lead from the host magma. Other evidence would indicate that an "accidental" origin be preferred. ?? 1968.

  16. Application of lead and strontium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    Science.gov (United States)

    Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Keegan, Elizabeth; Millet, Sylvain

    2009-10-15

    Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic (207)Pb/(206)Pb ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The (87)Sr/(86)Sr isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.

  17. Lead isotopic evolution of Archean continental crust, Northern Tanzania

    Science.gov (United States)

    Bellucci, J. J.; McDonough, W. F.; Rudnick, R. L.; Walker, R. J.

    2010-12-01

    The continental crust is stratified in composition; the upper crust is generally enriched in highly incompatible trace elements relative to the lower crust [1]. The Western Granulite section of the Mozambique Belt of Northern Tanzania yields Archean Nd model ages and has zircons with U-Pb ages of ~2.6 Ga [2,3], but was strongly re-worked during the Pan-African Orogeny, ca. 560 Ma [2,3,4]. Here we use time-integrated Pb isotopic modeling for lower and middle crustal xenoliths, as well as upper crustal granulites to determine the timing of, and degree of intra-crustal differentiation. The Pb isotopic compositions of most feldspars in the lower crustal samples, measured via LA-MC-ICPMS, fall on the trend defined by the Tanzanian Craton [5] and therefore, were most likely extracted from the mantle at a similar time, ca. 2.7 Ga. However, some xenoliths fall off this trend and show enrichment in 207Pb/204Pb, which we interpret as reflecting derivation from more heterogeneous mantle than that sampled in the Tanzanian Craton. In contrast to lower crustal xenoliths from the Tanzanian Craton [5], we see no single feldspar Pb-Pb isochrons, which indicates complete re-homogenization of the Pb isotopic composition of the feldspars in the lower crust of the Mozambique Belt during the Pan-African Orogeny, and heating to > 600°C [5]. Using time integrated Pb modeling, the upper crust of the Western Granulites is enriched in U by ˜ 2.5 relative to that of the lower crust, which must have taken place around the time of mantle extraction (ca. 2.7 Ga). In addition, these calculations are consistent with a Th/U ratio of ˜ 4 for the bulk lower crust and ˜ 3 for the bulk upper crust. The common Pb isotopic composition of a single middle crustal xenolith implies a Th/U of 20, but is unlikely to be generally representative of the middle crust. [1] Rudnick, R. L. and Gao, S. (2003). In the Crust, vol. 3, Treatise on Geochemistry:1-64. [2] Mansur, A. (2008) Masters Thesis, University of

  18. Lead (Pb) Isotope Baselines for Studies of Ancient Human Migration and Trade in the Maya Region.

    Science.gov (United States)

    Sharpe, Ashley E; Kamenov, George D; Gilli, Adrian; Hodell, David A; Emery, Kitty F; Brenner, Mark; Krigbaum, John

    2016-01-01

    We examined the potential use of lead (Pb) isotopes to source archaeological materials from the Maya region of Mesoamerica. The main objectives were to determine if: 1) geologic terrains throughout the Maya area exhibit distinct lead isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb), and 2) a combination of lead and strontium ratios can enhance sourcing procedures in the Mesoamerica region. We analyzed 60 rock samples for lead isotope ratios and a representative subset of samples for lead, uranium, and thorium concentrations across the Maya region, including the Northern Lowlands of the Mexican Yucatan Peninsula, the Southern Lowlands of Guatemala and Belize, the Volcanic Highlands, the Belizean Maya Mountains, and the Metamorphic Province/Motagua Valley. Although there is some overlap within certain sub-regions, particularly the geologically diverse Metamorphic Province, lead isotopes can be used to distinguish between the Northern Lowlands, the Southern Lowlands, and the Volcanic Highlands. The distinct lead isotope ratios in the sub-regions are related to the geology of the Maya area, exhibiting a general trend in the lowlands of geologically younger rocks in the north to older rocks in the south, and Cenozoic volcanic rocks in the southern highlands. Combined with other sourcing techniques such as strontium (87Sr/86Sr) and oxygen (δ18O), a regional baseline for lead isotope ratios can contribute to the development of lead isoscapes in the Maya area, and may help to distinguish among geographic sub-regions at a finer scale than has been previously possible. These isotope baselines will provide archaeologists with an additional tool to track the origin and movement of ancient humans and artifacts across this important region.

  19. Stable lead isotopes in environmental health with emphasis on human investigations

    Energy Technology Data Exchange (ETDEWEB)

    Gulson, Brian [Graduate School of the Environment, Macquarie University, Sydney NSW 2109 (Australia); CSIRO Exploration and Mining North Ryde NSW 1670 (Australia)], E-mail: bgulson@gse.mq.edu.au

    2008-08-01

    There has been widespread use of stable lead isotopes in the earth sciences for more than 40 years focussed on the origin and age of rocks and minerals with lesser application in environmental investigations where the emphasis has been directed typically to the source of lead in environmental media such as air, water and soils. In contrast, the number of environmental health investigations focussed on humans (and primates) is limited in spite of the demonstrated utility of the approach in pioneering studies in the early 1970's. This paper reviews the status of lead isotopes in human investigations especially over the past 2 decades, the period over which most activity has taken place. Following a brief introduction to the method, examples are provided illustrating the use of lead isotopes in a wide spectrum of activities including sources and pathways of lead in diverse environments from urban to mining communities, various applications associated with pregnancy, the contribution of bone lead to blood lead including in the elderly, the half-life of lead in blood, and lead in bones and other media. A brief outline of critical research on non-human primates is also given. The lead isotope method is a powerful technique for tracing lead and could be employed more widely in human investigations.

  20. A simplified method for obtaining high-purity perchlorate from groundwater for isotope analyses.

    Energy Technology Data Exchange (ETDEWEB)

    vonKiparski, G; Hillegonds, D

    2011-04-04

    Investigations into the occurrence and origin of perchlorate (ClO{sub 4}{sup -}) found in groundwater from across North America have been sparse until recent years, and there is mounting evidence that natural formation mechanisms are important. New opportunities for identifying groundwater perchlorate and its origin have arisen with the utilization of improved detection methods and sampling techniques. Additionally, application of the forensic potential of isotopic measurements has begun to elucidate sources, potential formation mechanisms and natural attenuation processes. Procedures developed appear to be amenable to enable high precision stable isotopic analyses, as well as lower precision AMS analyses of {sup 36}Cl. Immediate work is in analyzing perchlorate isotope standards and developing full analytical accuracy and uncertainty expectations. Field samples have also been collected, and will be analyzed when final qa/qc samples are deemed acceptable.

  1. Origins of inhabitants from the 16th century Sala (Sweden) silver mine cemetery – a lead isotope perspective

    DEFF Research Database (Denmark)

    Price, T. Douglas; Frei, Robert; Bäckström, Ylva

    2017-01-01

    however. Here we utilize lead isotopes as an additional isotopic tracer to identify origins. The lead isotope investigations pinpoint several areas outside of the Sala region where some of the inhabitants originated. In addition, the study documents the benefits of using lead isotopes in human...... these grave types, as well as harsh conditions of life. Strontium and oxygen isotopes have been used previously to investigate the place of origin of the cemetery inhabitants and clear differences among the types of graves were seen in the isotope results. Place of origin was more difficult to ascertain...

  2. Service-Learning General Chemistry: Lead Paint Analyses

    Science.gov (United States)

    Kesner, Laya; Eyring, Edward M.

    1999-07-01

    Houses painted with lead-based paints are ubiquitous in the United States because the houses and the paint have not worn out two decades after federal regulations prohibited inclusion of lead in paint. Remodeling older homes thus poses a health threat for infants and small children living in those homes. In a service-learning general chemistry class, students disseminate information about this health threat in an older neighborhood. At some of the homes they collect paint samples that they analyze for lead both qualitatively and quantitatively. This service-learning experience generates enthusiasm for general chemistry through the process of working on a "real" problem. Sample collection familiarizes the students with the concept of "representative" sampling. The sample preparation for atomic absorption spectroscopic (AAS) analysis enhances their laboratory skills. The focus of this paper is on the mechanics of integrating this particular service project into the first-term of the normal general chemistry course.

  3. Nitrogen and Triple Oxygen Isotopic Analyses of Atmospheric Particulate Nitrate over the Pacific Ocean

    Science.gov (United States)

    Kamezaki, Kazuki; Hattori, Shohei; Iwamoto, Yoko; Ishino, Sakiko; Furutani, Hiroshi; Miki, Yusuke; Miura, Kazuhiko; Uematsu, Mitsuo; Yoshida, Naohiro

    2017-04-01

    Nitrate plays a significant role in the biogeochemical cycle. Atmospheric nitrate (NO3- and HNO3) are produced by reaction precursor as NOx (NO and NO2) emitted by combustion, biomass burning, lightning, and soil emission, with atmospheric oxidants like ozone (O3), hydroxyl radical (OH), peroxy radical and halogen oxides. Recently, industrial activity lead to increases in the concentrations of nitrogen species (NOx and NHy) throughout the environment. Because of the increase of the amount of atmospheric nitrogen deposition, the oceanic biogeochemical cycle are changed (Galloway et al., 2004; Kim et al., 2011). However, the sources and formation pathways of atmospheric nitrate are still uncertain over the Pacific Ocean because the long-term observation is limited. Stable isotope analysis is useful tool to gain information of sources, sinks and formation pathways. The nitrogen stable isotopic composition (δ15N) of atmospheric particulate NO3- can be used to posses information of its nitrogen sources (Elliott et al., 2007). Triple oxygen isotopic compositions (Δ17O = δ17O - 0.52 ×δ18O) of atmospheric particulate NO3- can be used as tracer of the relative importance of mass-independent oxygen bearing species (e.g. O3, BrO; Δ17O ≠ 0 ‰) and mass-dependent oxygen bearing species (e.g. OH radical; Δ17O ≈ 0 ‰) through the formation processes from NOx to NO3- in the atmosphere (Michalski et al., 2003; Thiemens, 2006). Here, we present the isotopic compositions of atmospheric particulate NO3- samples collected over the Pacific Ocean from 40˚ S to 68˚ N. We observed significantly low δ15N values for atmospheric particulate NO3- on equatorial Pacific Ocean during both cruises. Although the data is limited, combination analysis of δ15N and Δ17O values for atmospheric particulate NO3- showed the possibility of the main nitrogen source of atmospheric particulate NO3- on equatorial Pacific Ocean is ammonia oxidation in troposphere. Furthermore, the Δ17O values

  4. Provenance of dust to Antarctica: A lead isotopic perspective

    Science.gov (United States)

    Gili, Stefania; Gaiero, Diego M.; Goldstein, Steven L.; Chemale, Farid, Jr.; Koester, Edinei; Jweda, Jason; Vallelonga, Paul; Kaplan, Michael R.

    2016-03-01

    Antarctic ice preserves an ~800 kyr record of dust activity in the Southern Hemisphere. Major efforts have been dedicated to elucidate the origin of this material in order to gain greater insight into the atmospheric dust cycle. On the basis of Pb isotopes in Antarctic dust samples and potential sources, this contribution demonstrates for the first time that Patagonia is the main contributor of dust to Antarctica during interglacial periods as well as glacials, although the potential importance of Tierra del Fuego remains unclear because of its geochemical similarities to Patagonia. An important new finding is that the Puna-Altiplano sector of the continent is a second important dust source to eastern Antarctica during both glacials and interglacials, being more prominent during interglacials. The data indicate South America is the primary dust source to Antarctica during both glacials and interglacials.

  5. Regional variations in the lead isotopic composition of galena from southern Korea with implications for the discrimination of lead provenance

    Science.gov (United States)

    Jeong, Youn-Joong; Cheong, Chang-sik; Shin, Dongbok; Lee, Kwang-Sik; Jo, Hui Je; Gautam, Mukesh Kumar; Lee, Insung

    2012-11-01

    This study presents a comprehensive database (n = 215) of lead isotopes in galena from the southern Korean peninsula using new and published data. Of the 69 metal mines examined, predominantly skarn- and hydrothermal-type Pb-Zn-Au-Ag-Cu deposits were observed and were associated with Mesozoic magmatic activities. Galena samples from each geotectonic unit showed discrete lead isotopic signatures. The Gyeongsang basin samples were characteristically unradiogenic and had restricted variations in lead isotopic composition (206Pb/204Pb = 18.16-18.59, 207Pb/204Pb = 15.48-15.64, 208Pb/204Pb = 37.87-38.77). Their 208Pb/204Pb range indicated an involvement of source materials less thorogenic than the associated granites. The galena samples from Cambro-Ordovician carbonate rocks of the northeastern Yeongnam massif and eastern Taebaeksan basin had the most radiogenic 206Pb/204Pb (19.28 ± 0.14) and 207Pb/204Pb (15.833 ± 0.027) ratios. Their lead isotopic trend indicated a combined contribution of ore lead from granitic magmas, Precambrian basements, and overlain host rocks. Less radiogenic galena samples from the middle to southwestern parts of the Yeongnam massif and Okcheon belt showed limited lead isotopic variations (206Pb/204Pb = 18.332 ± 0.065, 207Pb/204Pb = 15.693 ± 0.012, 208Pb/204Pb = 38.93 ± 0.07 on average), probably resulted from mixing with a common crustal basement. The differences in lead isotopes between the radiogenic and unradiogenic groups from the Yeongnam massif and Okcheon belt may reflect the spatial dissimilarity of involved crustal rocks. The old crust appears to have significantly contributed ore lead to galenas from the western Gyeonggi massif, but the geochronological meaning of their steep 207Pb/204Pb-206Pb/204Pb trend is not clear. The comprehensive database constructed by the present study suggests that lead province in the southern Korean peninsula may be subdivided into four discrete zones. Linear discriminant analysis showed that more

  6. Isotopic source signatures for atmospheric lead: the Southern Hemisphere

    Science.gov (United States)

    Bollhöfer, A.; Rosman, K. J. R.

    2000-10-01

    Aerosols collected between 1994 and 1999 at more than 70 different sites affecting the Southern Hemisphere have been measured for their 206Pb/ 207Pb, 208Pb/ 207Pb and 206Pb/ 204Pb ratios and Pb concentrations. Lower ratios are found at the southern tips of Africa, Australia and South America probably due to the supply of alkyllead from a common supplier such as Associated Octel. The ratios increase in a northerly direction probably due to a changing market share in alkyllead or an increasing industrial Pb contribution. The geographical variations in isotopic signatures made it possible to broadly characterize the different regions that influence the Southern Hemisphere. Brazil and Argentina exhibited 206Pb/ 207Pb, 208Pb/ 207Pb and 206Pb/ 204Pb ratios in aerosols of 1.141-1.184, 2.416-2.442 and 17.77-18.57, respectively. Mexican aerosols had values of 1.188-1.197, 2.452-2.463 and 18.46-18.73. Aerosols sampled in Chile had low ratios in the South of 1.063-1.094, 2.337-2.373 and 16.46-17.13 which increased in a northerly direction. Emissions from South Africa were characterized by ratios 1.067-1.090, 2.340-2.358 and 16.53-16.99. In 1994-1995 Australia and New Zealand had ratios of 1.060-1.193, 2.324-2.445 and 16.08-18.54. In 1997 however, the range was narrower: 1.072-1.112, 2.342-2.398 and 16.55-17.36, respectively. These isotopic signatures are potentially useful for tracing sources of pollution and the movement of air-masses on a global scale.

  7. Mixing of water in a carbonate aquifer, southern Italy, analysed through stable isotope investigations

    Directory of Open Access Journals (Sweden)

    Petrella Emma

    2013-01-01

    Full Text Available Mixing of water was analysed in a carbonate aquifer, southern Italy, through stable isotope investigations (18O,δ2H. The input signal (rainwater was compared with the isotopic content of a 35-meter groundwater vertical prof ile, over a 1-year period. Within the studied aquifer, recharge and f low are diffuse in a well-connected f issure network.At the test site, the comparison between input and groundwater isotopic signals illustrates that no eff icient mixing takes place in the whole unsaturated zone, between the fresh inf iltration water and the stored water.When analysing the stable isotope composition of groundwater, signif icant variations were observed above the threshold elevation of 1062 m asl, while a nearly constant composition was observed below the same threshold. Thus, temporal variations in stable isotope composition of rainwater are completely attenuated just in the deeper phreatic zone.On the whole, taking into consideration also the results of previous studies in the same area, the investigations showed that physical characteristics of the carbonate bedrock, as well as aquifer heterogeneity, are factors of utmost importance in inf luencing the complete mixing of water. These f indings suggest a more complex scenario at catchment scale.

  8. Lead isotope determinations from sulfide mineral occurrences--Russian Far East

    Science.gov (United States)

    Church, Stanley E.; Goryachev, Nikolai A.; Shpikerman, Vladimir I.

    2013-01-01

    The lead isotope database for sulfide deposits and occurrences in the Russian Far East was funded by the Mineral Resources Program, U.S. Geological Survey (USGS) in conjunction with the collaborative studies of mineral resources by the Russian Academy of Sciences and the U. S. Geological Survey (Nokleberg and others, 1996). Comparisons of these data with similar lead isotope data from Alaska published in Church, Delevaux, and others (1987) and Gaccetta and Church (1989) provide a basis for the following three-fold project objectives: 1. To utilize lead isotope signatures, in conjunction with regional mapping, to assess the relative ages and to categorize the types of mineral deposits studied, 2. To relate the lead isotope and trace-element geochemical signatures of specific deposits and occurrences to ore-forming processes, and 3. To use the lead isotope data to correlate lithotectonic terranes within the northern Cordillera (Alaska, Yukon Territories and British Columbia in Canada, and the western Cordillera of the United States). The report by Church, Gray, and others (1987) shows how this fingerprinting methodology can be applied to trace the offset of lithotectonic (or lithostratigraphic as labeled by some authors) terranes.The lead isotope data presented in table 1 represent the work completed on sulfide mineral deposits located in the Russian Far East from 1993 to 1995, when this study was terminated due to lack of funding. The lead isotope data are reported here for use by investigators who may find them of value in mineral exploration. No attempt is made to summarize the voluminous literature on these mineral deposits.

  9. Rubidium isotopes in primitive chondrites: Constraints on Earth's volatile element depletion and lead isotope evolution

    Science.gov (United States)

    Nebel, O.; Mezger, K.; van Westrenen, W.

    2011-05-01

    The bulk silicate Earth (BSE) shows substantial deficits in volatile elements compared to CI-chondrites and solar abundances. These deficits could be caused by pre-accretionary depletion in the solar nebula during condensation of solids, or by later heat-driven evaporation during collision of small bodies that later accreted to form the Earth. The latter is considered to result in isotope fractionation for elements with low condensation temperatures that correlates with the degree of depletion. Here, we report first high-precision isotope ratio measurements of the moderately volatile and lithophile trace element Rb. Data from seventeen chondrite meteorites show that their Rb isotope abundances are nearly indistinguishable from Earth, not deviating more than 1 per mil in their 87Rb/85Rb. The almost uniform solar system Rb isotope pool suggests incomplete condensation or evaporation in a single stage is unlikely to be the cause of the volatile element deficit of the Earth. As Rb and Pb have similar condensation temperatures, we use their different degrees of depletion in the BSE to address the mechanisms and timing of terrestrial volatile depletion. The Rb isotope data are consistent with a scenario in which the volatile budget of the Earth was generated by a mixture of a highly volatile-element depleted early Proto-Earth with undepleted material in the course of terrestrial accretion. Observed Pb and Rb abundances and U-Pb and Rb-Sr isotope systematics suggest that volatile addition occurred at approximately the same time at which last core-mantle equilibration was achieved. In line with previous suggestions, this last equilibration involved a second stage of Pb (but not Rb) depletion from the BSE. The timing of this second Pb loss event can be constrained to ~ 110 Ma after the start of the solar system. This model supports a scenario with core storage of Pb in the aftermath of a putative Moon forming giant impact that also delivered the bulk of the volatile

  10. The Rosetta Stone of isotope science and the uranium/lead system.

    Science.gov (United States)

    De Laeter, John

    2011-01-01

    The nucleosynthetic characteristics of U and Pb, together with the interconnectivity between these elements by two radioactive decay chains, are the foundation on which the U/Pb system was able to make a unique contribution to isotope science. The Rosetta Stone is an ancient Egyptian tablet that enabled previously indecipherable hieroglyphics to be translated. In a similar manner, the isotopic investigation of the U/Pb system, by a variety of mass spectrometric instrumentation, has led to our knowledge of the age of the Earth and contributed to thermochronology. In a similar manner, climate change information has been garnered by utilizing the U-Disequilibrium Series to measure the ages of marine archives. The impact of Pb in the environment has been demonstrated in human health, particularly at the peak of leaded petrol consumption in motor vehicles in the 1970s. Variations in the isotopic composition of lead in samples enable the source of the lead to be "fingerprinted" so as to trace the history of the Pb in ice cores and aerosols. The discovery of nuclear fission of (235)U led to the development of nuclear reactors and the isotopic investigation of the Oklo natural reactors. The mass spectrometer is the modern Rosetta Stone of isotope science, which has enabled the isotopic hieroglyphics of the U/Pb system to be investigated to reveal new horizons in our understanding of nature, and to address a number of societal and environmental problems.

  11. Lead and neodymium isotopic results from metabasalts of the Haveri Formation, southern Finland: evidence for Palaeoproterozoic enriched mantle

    Directory of Open Access Journals (Sweden)

    Vaasjoki, M.

    1999-06-01

    Full Text Available Tholeiitic metabasalts and coexisting sulphides have been analysed for their Pb and Nd isotopic compositions from the Proterozoic Haveri Formation, which forms the basal unit of the Tampere Schist Belt in southern Finland. Ten whole rock samples analysed for Pb isotopes form a sublinear array which yields rather uncertain age estimates in the 1900-2000 Ma range and lies on the 207Pb/204Pb vs. 206Pb/204Pb diagram well below the average global lead evolution curve. The initial lead isotopic composition inferred from the whole rock data and measured on chalcopyrite is the least radiogenic obtained from the Svecofennian domain, and precludes involvement of old upper crustal material in basalt genesis. This together with the geochemical composition and initial eNd (1900 of +0.5±0.6 suggest that the Haveri mafic metavolcanic rocks were not derived from convective MORB-type mantle. The source was rather a mantle, which had been enriched in LREE for a considerable time period. Some chalcopyrite trace leads plot close to the whole rock array while others lie above it. This is interpreted as indicating two distinct mineralisation processes. The primary and major process involved lead which was cogenetic with the basalts, while the second mineralising fluid introduced radiogenic (high 207Pb upper crustal lead scavenged from the adjacent sedimentary rocks. The least radiogenic leads at Haveri and in the Outokumpu ophiolite complex some 300 km NE are similar and the two occurrences can be coeval. The preservation of original mantle material at Haveri may be interpreted as suggesting that continental crust had formed in the Tampere area 1900-2000 Ma ago.

  12. Lead Isotopic Composition and Lead Source of the Huogeqi Cu-Pb-Zn Deposit, Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaoqing; ZHANG Qian; HE Yuliang; ZHU Chaohui

    2006-01-01

    The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies are stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic reworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentarymetamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks are introduced and compared with the ore-lead composition, so as to constrain the source of the ore lead. The result indicates that (1) sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their 206Pb/204Pb ratios are within a range of 17.027-17.317; 207pb/204pb ratios, 15.451-15.786 and 208Pb/204pb ratios, 36.747-37.669; (2) the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks are characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range,reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; (3) the sedimentary-metamorphic rocks in the mining district are characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios are obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic reworking of these rocks; (4) Pb isotopic compositions of Late Proterozoic diorite-gabbro and

  13. Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wan [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu Xiande [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)]. E-mail: liuxdlxd@hotmail.com; Zhao Liwei [Tianjin Environmental Monitoring Center, Tianjin, 300190 (China); Guo, Dongfa [Beijing Research Institute of Uranium Geology, Beijing 100029 (China); Tian Xiaodan [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium); Adams, Freddy [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium)

    2006-07-01

    The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The {sup 206}Pb / {sup 207}Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the {sup 206}Pb / {sup 207}Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The {sup 206}Pb / {sup 207}Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level.

  14. Effectiveness of leaded petrol phase-out in Tianjin, China based on the aerosol lead concentration and isotope abundance ratio

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wan; Liu, Xiande [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhao, Liwei [Tianjin Environmental Monitoring Center, Tianjin, 300190 (China); Guo, Dongfa [Beijing Research Institute of Uranium Geology, Beijing 100029 (China); Tian, Xiaodan; Adams, Freddy [University of Antwerp, UA, B-2610 Wilrijk-Antwerpen (Belgium)

    2006-07-01

    The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The {sup 206}Pb/{sup 207}Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the {sup 206}Pb/{sup 207}Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The {sup 206}Pb/{sup 207}Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level. (author)

  15. Identification of the sources of metal (lead) contamination in drinking waters in north-eastern Tasmania using lead isotopic compositions.

    Science.gov (United States)

    Harvey, P J; Handley, H K; Taylor, M P

    2015-08-01

    This study utilises a range of scientific approaches, including lead isotopic compositions, to differentiate unknown sources of ongoing lead contamination of a drinking water supply in north-eastern Tasmania, Australia. Drinking water lead concentrations are elevated above the Australian Drinking Water Guideline (10 μg/L), reaching 540 μg/L in the supply network. Water lead isotopic compositions from the town of Pioneer ((208)Pb/(207)Pb 2.406, (206)Pb/(207)Pb 1.144 to (208)Pb/(207)Pb 2.360, (206)Pb/(207)Pb 1.094) and Ringarooma ((208)Pb/(207)Pb 2.398, (206)Pb/(207)Pb 1.117) are markedly different from the local bedrock ((208)Pb/(207)Pb 2.496, (206)Pb/(207)Pb 1.237). The data show that the lead in the local waters is sourced from a combination of dilapidated drinking water infrastructure, including lead jointed pipelines, end-of-life polyvinyl chloride pipes and household plumbing. Drinking water is being inadvertently contaminated by aging infrastructure, and it is an issue that warrants investigation to limit the burden of disease from lead exposure.

  16. Lead isotopic compositions of common arsenical pesticides used in New England

    Science.gov (United States)

    Ayuso, Robert; Foley, Nora; Robinson, Gilpin; Wandless, Gregory; Dillingham, Jeremy

    2004-01-01

    The three most important arsenical pesticides and herbicides that were extensively used on apple, blueberry, and potato crops in New England from mid-1800s to recent times are lead arsenate, calcium arsenate, and sodium arsenate. Lead arsenate was probably the most heavily used of the arsenical pesticides until it was banned in 1988. Other metal-arsenic pesticides were also used but in lesser amounts. A recent report identified areas in New England where arsenical pesticides were used extensively (Robinson and Ayuso, 2004). On the basis of factor analysis of metal concentrations in stream sediment samples, a positive correlation with pesticide use was shown in regions having stream sediment sample populations that contained concentrations of high arsenic and lead. Lead isotope compositions of stream sediments from areas with heavy use of the pesticides could not be entirely explained by lead originating from rock sulfides and their weathering products. An industrial lead contribution (mostly from atmospheric deposition of lead) was suggested in general to explain the lead isotopic distributions of the stream sediments that could not be accounted for by the natural lead in the environment. We concluded that when agricultural land previously contaminated with arsenical pesticides is urbanized, pesticide residues in the soils and stream sediments could be released into the groundwater. No lead isotopic data characterizing the compositions of pesticides were available for comparison. We have determined the lead isotopic compositions of commonly used pesticides in New England, such as lead arsenate, sodium metaarsenite, and calcium arsenate, in order to assist in future isotopic comparisons and to better establish anthropogenic sources of Pb and As. New data are also presented for copper acetoarsenite (or Paris green), methyl arsonic acid and methane arsonic acid, as well as for arsanilic acid, all of which are used as feed additives to promote swine and poultry growth

  17. Lead isotope systematics of some igneous rocks from the Egyptian Shield

    Science.gov (United States)

    Gillespie, J. G.; Dixon, T. H.

    1983-01-01

    Lead isotope data on whole-rock samples and two feldspar separates for a variety of Pan-African (late Precambrian) igneous rocks for the Egyptian Shield are presented. It is pointed out that the eastern desert of Egypt is a Late Precambrian shield characterized by the widespread occurrence of granitic plutons. The lead isotope ratios may be used to delineate boundaries between Late Precambrian oceanic and continental environments in northeastern Africa. The samples belong to three groups. These groups are related to a younger plutonic sequence of granites and adamellites, a plutonic group consisting of older tonalites to granodiorites, and the Dokhan volcanic suite.

  18. Temporal variations in lead concentrations and isotopic composition in the Southern California Bight

    Energy Technology Data Exchange (ETDEWEB)

    Sanudo-Wilhelmy, S.A.; Flegal, A.R. (Univ. of California, Santa Cruz, CA (United States))

    1994-08-01

    Lead concentrations in surface waters of the Southern California Bight appear to have decreased threefold (from >170 to <60 pM) since they were initially measured by Clair Patterson and his associates in the 1970s. The decrease parallels a threefold decline in anthropogenic inputs of industrial lead to the bight over the past two decades. Moreover, mass balance calculations indicate that the primary source of lead to the bight now is upwelling. This is evidenced by the isotopic compositions of surface waters in the bight, which are most characteristic of Asian industrial lead aerosols (0.4793 [le] [sup 206]Pb/[sup 208]Pb [le] 0.4833) deposited in oceanic waters of the North Pacific. While the decrease in surface water lead concentrations in the bight reflects the reduction in industrial lead emissions from the United States, the isotopic compositions of surface waters in the southern reach of the bight reflect a concurrent increase in industrial lead emissions from Mexico (0.4852 [le] [sup 206]Pb/[sup 208]Pb [le] 0.4877). The isotopic composition ([sup 208]Pb/[sup 207]Pb [approximately] 2.427) of elevated lead concentrations of surface waters in San Diego Bay indicate that lead is being remobilized from contaminated sediments within that bay.

  19. Lead isotopes in sediments of the Loire River (France): natural versus anthropogenic origin

    Science.gov (United States)

    Negrel, Ph.; Petelet-Giraud, E.

    2012-04-01

    Sediments along the Loire River (central France) were investigated by means of lead isotopes determined on the labile sediment fraction, or acid-extractable matter (AEM). The combination of trace elements and lead isotopes allows deciphering the origin of the elements (i.e. natural or anthropogenic) and their history, both in the sediment and soil from two small watersheds (one draining basalt, the other one granite-gneiss gneiss in the upper part of the catchment), in present-day suspended matter in Loire River water, and in sediment from the Loire estuary. Fe-Mn oxides act as the main carrier phase of the elements in the AEM extracted by cold HBr, Th and Pb concentrations were determined by ICP-MS and lead isotopes by ICP-MS-MC Neptune. Thorium displays mostly insoluble behaviour in hydrosystems, but the small amount of dissolved Th shows a strong tendency to be adsorbed onto oxyhydroxides. Therefore, Mn and Th (as well as other trace elements) correlate well in AEM, the correlations of Mn, and Pb with Th as a typical indicator of crustal weathering points to their derivation from the silicate basement of the upstream part of the catchment. Crustal weathering, as confirmed by the Pb-isotope ratios for most sample points, is the main natural source of lead in the upstream part of the Loire River, as well as that transported in the middle part of the basin and up to the estuary. Among anthropogenic sources, the use of Pb-isotopic compositions shows an influence of agricultural lead-derived inputs and a large input from lead as a gasoline additive, particularly in the estuary due to harbour activities and for one downstream tributary river that is strongly marked by this type of lead input.

  20. Lead shot contribution to blood lead of First Nations people: The use of lead isotopes to identify the source of exposure

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Leonard J.S. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: ljtsuji@fes.uwaterloo.ca; Wainman, Bruce C. [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Martin, Ian D. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Sutherland, Celine [Attawapiskat First Nation Health Services, Attawapiskat, Ontario, P0L 1A0 (Canada); Weber, Jean-Philippe; Dumas, Pierre [Centre de toxicologie, Institut national de sante publique du Quebec, Quebec City, Quebec, G1V 5B3 (Canada); Nieboer, Evert [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Institute of Community Medicine, University of Tromso, Tromso N-9037 (Norway)

    2008-11-01

    Although lead isotope ratios have been used to identify lead ammunition (lead shotshell pellets and bullets) as a source of exposure for First Nations people of Canada, the actual source of lead exposure needs to be further clarified. Whole blood samples for First Nations people of Ontario, Canada, were collected from participants prior to the traditional spring harvest of water birds, as well as post-harvest. Blood-lead levels and stable lead isotope ratios prior to, and after the harvest were determined by ICP-MS. Data were analyzed by paired t-tests and Wilcoxon Signed-Ranks tests. All participants consumed water birds harvested with lead shotshell during the period of study. For the group excluding six males who were potentially exposed to other sources of lead (as revealed through a questionnaire), paired t-tests and Wilcoxon Signed-Ranks tests showed consistent results: significant (p < 0.05) increases in blood-lead concentrations and blood levels of {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb towards the mean values we previously reported for lead shotshell pellets; and a significant decrease in {sup 208}Pb/{sup 206}Pb values towards the mean for lead shotshell pellets. However, when we categorized the group further into a group that did not use firearms and did not eat any other traditional foods harvested with lead ammunition other than waterfowl, our predictions for {sup 206}Pb/{sup 204}Pb, {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 206}Pb hold true, but there was not a significant increase in blood-lead level after the hunt. It appears that the activity of hunting (i.e., use of a shotgun) was also an important route of lead exposure. The banning of lead shotshell for all game hunting would eliminate a source of environmental lead for all people who use firearms and/or eat wild game.

  1. Lead shot contribution to blood lead of First Nations people: the use of lead isotopes to identify the source of exposure.

    Science.gov (United States)

    Tsuji, Leonard J S; Wainman, Bruce C; Martin, Ian D; Sutherland, Celine; Weber, Jean-Philippe; Dumas, Pierre; Nieboer, Evert

    2008-11-01

    Although lead isotope ratios have been used to identify lead ammunition (lead shotshell pellets and bullets) as a source of exposure for First Nations people of Canada, the actual source of lead exposure needs to be further clarified. Whole blood samples for First Nations people of Ontario, Canada, were collected from participants prior to the traditional spring harvest of water birds, as well as post-harvest. Blood-lead levels and stable lead isotope ratios prior to, and after the harvest were determined by ICP-MS. Data were analyzed by paired t-tests and Wilcoxon Signed-Ranks tests. All participants consumed water birds harvested with lead shotshell during the period of study. For the group excluding six males who were potentially exposed to other sources of lead (as revealed through a questionnaire), paired t-tests and Wilcoxon Signed-Ranks tests showed consistent results: significant (plead concentrations and blood levels of (206)Pb/(204)Pb and (206)Pb/(207)Pb towards the mean values we previously reported for lead shotshell pellets; and a significant decrease in (208)Pb/(206)Pb values towards the mean for lead shotshell pellets. However, when we categorized the group further into a group that did not use firearms and did not eat any other traditional foods harvested with lead ammunition other than waterfowl, our predictions for (206)Pb/(204)Pb, (206)Pb/(207)Pb and (208)Pb/(206)Pb hold true, but there was not a significant increase in blood-lead level after the hunt. It appears that the activity of hunting (i.e., use of a shotgun) was also an important route of lead exposure. The banning of lead shotshell for all game hunting would eliminate a source of environmental lead for all people who use firearms and/or eat wild game.

  2. Tracing lead pollution sources in abandoned mine areas using stable Pb isotope ratios.

    Science.gov (United States)

    Yoo, Eun-Jin; Lee, Jung-A; Park, Jae-Seon; Lee, Khanghyun; Lee, Won-Seok; Han, Jin-Seok; Choi, Jong-Woo

    2014-02-01

    This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the (203)Tl/(205)Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios ((207)Pb/(206)Pb) found were 0.85073 ± 0.0004~0.85373 ± 0.0003 for the main stream, while they were 0.83736 ± 0.0010 for the tributary and 0.84393 ± 0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60%. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines.

  3. Roman road pollution assessed by elemental and lead isotope geochemistry in East Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Renson, Virginie [U.R. Argiles et Paleoclimats, University of Liege, Allee du 6 Aout, B18, Sart Tilman, 4000 Liege (Belgium)], E-mail: vrenson@vub.ac.be; Fagel, Nathalie [U.R. Argiles et Paleoclimats, University of Liege, Allee du 6 Aout, B18, Sart Tilman, 4000 Liege (Belgium); Mattielli, Nadine [Departement des Sciences de la Terre et de l' Environnement, Universite Libre de Bruxelles, CP160/02, Avenue F.D. Roosevelt, 1050 Brussels (Belgium); Nekrassoff, Serge [Station Scientifique des Hautes Fagnes 137, Rue de Botrange, 4950 Robertville (Belgium); Streel, Maurice [U.R.P.P.M., University of Liege, Allee du 6 Aout, B18, Sart Tilman, 4000 Liege (Belgium); De Vleeschouwer, Francois [U.R. Argiles et Paleoclimats, University of Liege, Allee du 6 Aout, B18, Sart Tilman, 4000 Liege (Belgium)

    2008-12-15

    The ability of inorganic geochemistry to record environmental change and especially human impact has been evidenced by several studies across Europe, especially in peat, where it is possible to record the impact of agriculture, mining and other industries. However, despite the numerous investigations on the impact of ancient human activities such as ore mining and smelting, little attention has been paid to geochemistry as a tool to solve problems of palaeopollution in the surroundings of archaeological sites. This paper presents geochemical evidence of the impact of a possible early Roman road built in SE Belgian peatland. Increased Zn and Pb concentrations suggest that Pb-Zn ores were transported on the road. Lead isotope analyses suggest that these ores are locally derived, being compatible with those found in the nearby Pb-Zn ore deposits from East Belgium. Present results provide direct evidence that East Belgian Pb-Zn ores were already being mined during Roman times, i.e. earlier than previously suspected (i.e. 14th century) and that Zn appears to be relatively immobile here. On a broader scale, it also demonstrates that such an early road already had an impact on the environment in terms of metal pollution. This paper enlarges on the range of possibilities offered by geochemistry in the field of geoarchaeology.

  4. Multi-element and isotopic analyses of iron meteorites using a glow discharge mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Shimamura, Tadashi (Kitasato Univ., Sagamihara (Japan). School of Hygienic Sciences); Takahashi, Takako (Marubun Corp., Kotoku, Tokyo (Japan). Analytical Research Lab.); Honda, Masatake; Nagai, Hisao (Nihon Univ., Tokyo (Japan). Coll. of Humanities and Sciences)

    1993-04-01

    Multi-element and isotopic analyses were performed of eight iron meteorites using a glow discharge mass spectrometer. Virtually all the elements can be determined. Major components (Fe, Co and Ni) through to ultra-trace constituents at the sub ng g[sup -1] level (Sc etc.) are measured directly with minimum chemical treatment within the same analytical cycle. Extremely high relative concentrations of Ni, Cu, Pd, In, Sn, Sb, Te, Pb and Bi were found in the meteorite Yamato 791694; the concentration of C was also very high. The isotopic composition of Pb in this meteorite was close to primordial. Low concentrations of C, N and O were found in the meteorite Gibeon. Very low S and Zn and high Cr and V were found in a third meteorite, Chinga. An excess of [sup 53]Cr was observed in Yamato 75031, which was consistent with the cosmic ray production level expected from the concentration of [sup 45]Sc. (Author).

  5. A Fourier transform infrared trace gas and isotope analyser for atmospheric applications

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2012-10-01

    Full Text Available Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities of greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO2, methane (CH4, carbon monoxide (CO, nitrous oxide (N2O and 13C in CO2 in air with high precision. High accuracy is established by reference to measurements of standard reference gases. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch for baseline measurements in the unpolluted troposphere for all species except 13C in CO2.

    The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows its application in isotopic tracer experiments, for example in tracing variations of 13C in CO2 and 15N in N2O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.

  6. Spent lead-acid battery recycling in China - A review and sustainable analyses on mass flow of lead.

    Science.gov (United States)

    Sun, Zhi; Cao, Hongbin; Zhang, Xihua; Lin, Xiao; Zheng, Wenwen; Cao, Guoqing; Sun, Yong; Zhang, Yi

    2017-06-01

    Lead is classified to be one of the top heavy metal pollutants in China. The corresponding environmental issues especially during the management of spent lead-acid battery have already caused significant public awareness and concern. This research gives a brief overview on the recycling situation based on an investigation of the lead industry in China and also the development of technologies for spent lead-acid batteries. The main principles and research focuses of different technologies including pyrometallurgy, hydrometallurgy and greener technologies are summarized and compared. Subsequently, the circulability of lead based on the entire life cycle analyses of lead-acid battery is calculated. By considering different recycling schemes, the recycling situation of spent lead-acid battery in China can be understood semi-quantitatively. According to this research, 30% of the primary lead production can be shut down that the lead production can still ensure consecutive life cycle operation of lead-acid battery, if proper management of the spent lead-acid battery is implemented according to current lead industry situation in China. This research provides a methodology on the view of lead circulability in the whole life cycle of a specific product and is aiming to contribute more quantitative guidelines for efficient organization of lead industry in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Lead isotopic evidence for evolutionary changes in magma-crust interaction, Central Andes, southern Peru

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro, B.A. (California Univ., Santa Barbara (USA). Dept. of Geological Sciences); Clark, A.H. (Queen' s Univ., Kingston, Ontario (Canada). Dept. of Geological Sciences)

    1984-07-01

    Lead isotopic measurements were made on Andean igneous rocks of Jurassic to Recent age in Moquegua and Tacna Departments, southernmost Peru, to clarify the petrogenesis of the rocks and, in particular, to investigate the effect of crustal thickness on rock composition. This location in the Cordillera Occidental is ideal for such a study because the ca. 2 Ga Precambrian basement rocks (Arequipa massif) have a distinct Pb isotopic signature which is an excellent tracer of crustal interaction, and because geomorphological research has shown that the continental crust was here thickened drastically in the later Tertiary.

  8. Insights into past atmospheric lead emissions using lead concentrations and isotopic compositions in historic lichens and fungi (1852-2008) from central and southern Victoria, Australia

    Science.gov (United States)

    Wu, Liqin; Taylor, Mark Patrick; Handley, Heather K.; Gulson, Brian L.

    2016-08-01

    Lead concentrations and lead isotopic compositions were determined in historic central and southern Victoria, Australia lichen (Cladonia and Usnea) and fungi (Trametes) samples collected between 1852 and 2008 to evaluate long-term atmospheric lead contamination sources. The data are grouped into four time intervals of 1850-1931, 1932-1984, 1985-2001 and 2002-2008 corresponding to the history of leaded petrol use in Australia. Elevated lichen and fungi lead concentrations and relatively high isotopic compositions from the period 1850-1931 are attributed to lithogenic sources, gold mining activities and early industrialisation. Significant increases in lichen and fungi lead concentrations and concomitant lower lead isotopic compositions correspond to the marked increase in lead emissions from leaded petrol use after 1932. Following the end of leaded petrol use in 2002 lead isotopic composition values 'recover' toward more lithogenic values. However, the lead isotopic composition data indicate that the environmental impact from leaded petrol emissions persists in contemporary samples dated to 2002-2008. Overall, the data reveal that herbarium lichens and fungi from central and southern Victoria can be used as proxies for environmental lead emissions over the past 150 years.

  9. Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

    Science.gov (United States)

    Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

    1996-01-01

    Lead-isotopic data on galena samples collected from a paragenetically constrained suite of samples from the Silesian-Cracow ore district show no regional or paragenetically controlled lead-isotopic trends within the analytical reproducibility of the measurements. Furthermore, the new lead-isotopic data agree with previously reported lead-isotopic results (R. E. Zartman et al., 1979). Sulfur-isotopic analyses of ores from the Silesian-Cracow district as well as from vein ore from the Gory Swietokrzyskie Mts. and the Myszkow porphyry copper deposit, when coupled with trace-element data from the galena samples, clearly discriminate different hydrothermal ore-forming events. Lead-isotopic data from the Permian and Miocene evaporite deposits in Poland indicate that neither of these evaporite deposits were a source of metals for the Silesian-Cracow district ores. Furthermore, lead-isotopic data from these evaporite deposits and the shale residues from the Miocene halite samples indicate that the crustal evolution of lead in the central and western European platform in southern Poland followed normal crustal lead-isotopic growth, and that the isotopic composition of crustal lead had progressed beyond the lead-isotopic composition of lead in the Silesian-Cracow ores by Permian time. Thus, Mesozoic and Tertiary sedimentary flysch rocks can be eliminated as viable source rocks for the metals in the Silesian-Cracow Mississippi Valley-type (MVT) deposits. The uniformity of the isotopic composition of lead in the Silesian-Cracow ores, when coupled with the geologic evidence that mineralization must post-date Late Jurassic faulting (E. Gorecka, 1991), constrains the geochemical nature of the source region. The source of the metals is probably a well-mixed, multi-cycle molasse sequence of sedimentary rocks that contains little if any Precambrian metamorphic or granitic clasts (S. E. Church, R. B. Vaughn, 1992). If ore deposition was post Late Jurassic (about 150 m. y.) or later

  10. Sulfur- and lead-isotope signatures of orogenic gold mineralisation associated with the Hill End Trough, Lachlan Orogen, New South Wales, Australia

    Science.gov (United States)

    Downes, P. M.; Seccombe, P. K.; Carr, G. R.

    2008-11-01

    The Hill End Trough (HET) is a deformed middle Silurian to Early Devonian sediment-dominated rift within the northeastern Lachlan Orogen. The HET hosts the Hill End, Hargraves, Napoleon Reefs, Stuart Town and Windeyer low-sulfide orogenic gold deposits. Adjacent to the HET are the Bodangora and Gulgong gold deposits. In this study we present 91 new sulfur- and 18 new lead-isotope analyses and collate a further 25 sulfur- and 32 lead-isotopes analyses from unpublished sources for these deposits. Larger gold deposits in the HET have near 0 δ34S‰ values indicating that sulfur in these systems was sourced from a magmatic reservoir. The dominant lead isotope signature for HET-hosted deposits reflects a crustal source however some mantle-derived lead has been introduced into the HET. Sulfur- and lead-isotopic results suggest that gold was sourced from mantle-derived magmatic units beneath the HET. The study supports earlier studies at Hill End by concluding that the majority of orogenic gold mineralisation in and adjacent to the HET formed during the Early Carboniferous period.

  11. Stable Isotope and Signature Fatty Acid Analyses Suggest Reef Manta Rays Feed on Demersal Zooplankton: e77152

    National Research Council Canada - National Science Library

    Lydie I E Couturier; Christoph A Rohner; Anthony J Richardson; Andrea D Marshall; Fabrice R A Jaine; Michael B Bennett; Kathy A Townsend; Scarla J Weeks; Peter D Nichols

    2013-01-01

    .... Stable isotope and signature fatty acid analyses of muscle tissue were used for the first time to examine assimilated diet of the reef manta ray Manta alfredi, and were compared with different...

  12. Sulfur and lead isotopic evidence of relic Archean sediments in the Pitcairn mantle plume

    Science.gov (United States)

    Delavault, Hélène; Chauvel, Catherine; Thomassot, Emilie; Devey, Colin W.; Dazas, Baptiste

    2016-11-01

    The isotopic diversity of oceanic island basalts (OIB) is usually attributed to the influence, in their sources, of ancient material recycled into the mantle, although the nature, age, and quantities of this material remain controversial. The unradiogenic Pb isotope signature of the enriched mantle I (EM I) source of basalts from, for example, Pitcairn or Walvis Ridge has been variously attributed to recycled pelagic sediments, lower continental crust, or recycled subcontinental lithosphere. Our study helps resolve this debate by showing that Pitcairn lavas contain sulfides whose sulfur isotopic compositions are affected by mass-independent fractionation (S-MIF down to Δ33S = -0.8), something which is thought to have occurred on Earth only before 2.45 Ga, constraining the youngest possible age of the EM I source component. With this independent age constraint and a Monte Carlo refinement modeling of lead isotopes, we place the likely Pitcairn source age at 2.5 Ga to 2.6 Ga. The Pb, Sr, Nd, and Hf isotopic mixing arrays show that the Archean EM I material was poor in trace elements, resembling Archean sediment. After subduction, this Archean sediment apparently remained stored in the deep Earth for billions of years before returning to the surface as Pitcairńs characteristic EM I signature. The presence of negative S-MIF in the deep mantle may also help resolve the problem of an apparent deficit of negative Δ33S anomalies so far found in surface reservoirs.

  13. Determining the geographical origin of Chinese cabbages using multielement composition and strontium isotope ratio analyses

    Science.gov (United States)

    BONG, Y.; Shin, W.; Gautam, M. K.; Jeong, Y.; Lee, A.; Jang, C.; Lim, Y.; Chung, G.; Lee, K.

    2012-12-01

    Recently, the Korean market has seen many cases of Chinese cabbage (Brassica rapa ssp. pekinensis) that have been imported from China, yet are sold as a Korean product to illegally benefit from the price difference between the two products. This study aims to establish a method of distinguishing the geographical origin of Chinese cabbage. One hundred Chinese cabbage heads from Korea and 60 cabbage heads from China were subjected to multielement composition and strontium isotope ratio (87Sr/86Sr) analyses. The 87Sr/86Sr ratio differed, based on the geological characteristics of their district of production. In addition, the content of many elements differed between cabbages from Korea and China. In particular, the difference in the content of Sr and Ti alone and the combination of Sr, Ca, and Mg allowed us to distinguish relatively well between Korea and China as the country of origin. The present study demonstrates that the chemical and Sr isotopic analyses exactly reflect the geology of the production areas of Chinese cabbage. Also, multivariate statistical analyses of multiple elements were found to be very effective in distinguishing the geographical origin of Chinese cabbages.

  14. Determination of lead, cadmium and thallium in water samples at ppb and ppt-levels by isotope dilution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Trettenbach, J.; Heumann, K.G.

    1985-10-01

    An analytical procedure by isotope dilution mass spectrometry for the simultaneous determination of lead, cadmium and thallium traces in water samples down to the ppt-level is described. As a definitive method this type of analysis is especially advantageous to calibrate other analytical methods. A cathodic electrodeposition is used for the separation of the analysed heavy metals. A spike solution containing SWPb, WCd and STTl is applied for the isotope dilution technique. Positive thermal ions of the elements are successively measured by increasing the temperature of the filament in a single-filament ion source. The blank contribution of chemicals of different degree of purity for the analytical procedure was investigated. Different spring water samples dependent on the type of soil were analysed. Drinking water samples showed a significant difference in the heavy metal concentration dependent on the frequency in which the water-pipe was used. In this case, thallium is an especially sensitive indicator. It has been found for lead and cadmium that in contrast to thallium a high portion of both elements is fixed at small particles which can be included in the drinking water or is adsorbed at the surface of a quartz vessel. (orig.).

  15. Metagenomic and stable isotopic analyses of modern freshwater microbialites in Cuatro Ciénegas, Mexico.

    Science.gov (United States)

    Breitbart, Mya; Hoare, Ana; Nitti, Anthony; Siefert, Janet; Haynes, Matthew; Dinsdale, Elizabeth; Edwards, Robert; Souza, Valeria; Rohwer, Forest; Hollander, David

    2009-01-01

    Ancient biologically mediated sedimentary carbonate deposits, including stromatolites and other microbialites, provide insight into environmental conditions on early Earth. The primary limitation to interpreting these records is our lack of understanding regarding microbial processes and the preservation of geochemical signatures in contemporary microbialite systems. Using a combination of metagenomic sequencing and isotopic analyses, this study describes the identity, metabolic potential and chemical processes of microbial communities from living microbialites from Cuatro Ciénegas, Mexico. Metagenomic sequencing revealed a diverse, redox-dependent microbial community associated with the microbialites. The microbialite community is distinct from other marine and freshwater microbial communities, and demonstrates extensive environmental adaptation. The microbialite metagenomes contain a large number of genes involved in the production of exopolymeric substances and the formation of biofilms, creating a complex, spatially structured environment. In addition to the spatial complexity of the biofilm, microbial activity is tightly controlled by sensory and regulatory systems, which allow for coordination of autotrophic and heterotrophic processes. Isotopic measurements of the intracrystalline organic matter demonstrate the importance of heterotrophic respiration of photoautotrophic biomass in the precipitation of calcium carbonate. The genomic and stable isotopic data presented here significantly enhance our evolving knowledge of contemporary biomineralization processes, and are directly applicable to studies of ancient microbialites.

  16. Use of isotope ratios to identify sources contributing to pediatric lead poisoning in Peru.

    Science.gov (United States)

    Naeher, Luke P; Rubin, Carol S; Hernandez-Avila, Mauricio; Noonan, Gary P; Paschal, Dan; Narciso, Juan; Lain, Rocio Espinoza; Gastanaga, Carmen; Almeyda, Rosa; Jarrett, Jeff; Caldwell, Kathleen L; McGeehin, Michael

    2003-09-01

    In 1998, a school-based blood lead level (BLL) survey of 2,510 children, conducted in Lima and Callao, Peru, revealed elevated BLLs in children from 2 Callao schools (mean BLL = 25.6 microg/dl; n = 314) and in children from Callao overall (mean BLL = 15.2 microg/dl; n = 898), compared with children from Lima (mean BLL = 7.1 microg/dl; n = 1,612). Public health officials at Peru's Direccion General de Salud Ambiental (DIGESA) hypothesized that a possible source of the elevated pediatric BLLs observed in Callao was a large depository near the port where mineral concentrates are stored prior to shipment. The U.S. Centers for Disease Control and Prevention worked with DIGESA to identify source(s) that contributed to the pediatric lead poisonings by comparing isotopic profiles of lead in blood, mineral, gasoline, and air filter samples. The lead isotope ratio (IR) observed in mineral samples from the depository in Callao differed from those in gasoline samples from Lima and Callao. The blood lead IRs of children living near the depository were similar to the IRs of the mineral samples and different from the IRs of the gasoline samples, suggesting that lead from the depository-and not gasoline-was the primary source of lead in these children. Lead IR analysis of regional air filter samples supported these findings.

  17. Lead concentration and isotope chronology in two coastal environments in Western and South East Asia

    Science.gov (United States)

    Carrasco, G. G.; Chen, M.; Boyle, E. A.; Zhao, N.; Nurhati, I. S.; Gevao, B.; al Ghadban, A.; Switzer, A.; Lee, J. M.

    2014-12-01

    Lead is a trace metal that is closely related to anthropogenic activity, mainly via leaded gasoline and coal combustion. The study of lead concentrations and isotopes in seawater, sediments, corals and aerosols allows for a systematic look at its sources and their time evolution in a natural environment. We will discuss results from two projects in Western and South East Asia, regions that have seen dramatic socio-economical changes over the past half-century that may have left environmental signals. These results highlight the usefulness of the method, indicate the degree of complexity of these systems, and point to the need for a continuous monitoring of anthropogenic trace metals in the small-medium coastal scale to be able to asses the larger scale effects of human activity. On the one hand, coastal Kuwait is heavily influenced by the Shat al-Arab river and shows a clear anthropogenic signature from Kuwait city. A mix of two sources can be tracked through the coral and sediment chronological records, with Pb206/Pb207 ratios (1.202 and 1.151) that approach the suspected source values (1.21 and 1.12) and eliminate the possibility of other sources. Through a wide sediment geographic distribution, the strength of the anthropogenic signature is modulated. On the other hand, Singapore offers a more complex system, where an apparent mix of two sources (extreme isotope ratios 1.215 and ~1.14) occurs also, but where either an unresolved potentially important third source (isotope ratio ~1.18), or an isotope exchange process should be invoked. The sediment and coral records allows us to track the changes through time; however, there seems to be incongruence with the aerosol isotope record. Further potential sources are being explored currently and will be discussed.

  18. GEMAS: a new view of the lead isotopic soil landscape at the European continental scale

    Science.gov (United States)

    Reimann, Clemens; Négrel, Philippe; Flem, Belinda; Fabian, Karl; Birke, Manfred; Ladenberger, Anna; Hoogewerff, Jurian

    2014-05-01

    Soil formation through weathering of bedrock and sediments is an extremely slow process, and soils must be considered an essential and non-renewable resource. Knowledge and extrapolation of threats to soils, e.g., changes in element concentrations and the reasons thereof are of primary importance for society as recently diffuse contamination has been identified as one of the major threats to soil quality. In this frame the addition of isotope tracing at the continental scale is an important supplementary constraint on the origin and behaviour of elements in soils. Lead has been mined and utilized by humans for several thousand years. The accumulated world production is estimated to be over 300 Mt. Detailed studies on environmental samples (e.g., peat bogs, ice cores, sediment cores) suggest a major Pb contamination of the northern hemisphere since ancient times. In spite of its importance the continental scale distribution of lead and lead isotopes combined has never been documented for any geochemical sample material. As the result of a combined effort of the European Geological Surveys, backed by the European metals industry, we present the first continental investigation of Pb concentration and Pb isotope ratios (206Pb,207Pb, 208Pb) landscape using agricultural soil samples (Ap-horizon, 0-20 cm) collected at an average density of 1 site/2500 km2 (2211 samples in total). Thus we here provide the first geochemical reference maps of Pb concentrations combined with Pb isotope ratios at the European scale against which the impact of contamination can be realistically judged. The maps localize the major concentration anomalies of Pb in soils and help to identify the processes that generate the observed distribution patterns. The European continental-scale patterns of Pb concentrations and Pb isotopes show a high variability dominated by geology and influenced by climate. Positive Pb concentration anomalies mark most of the known mineralized areas throughout Europe

  19. Zn/Cd ratios and cadmium isotope evidence for the classification of lead-zinc deposits.

    Science.gov (United States)

    Wen, Hanjie; Zhu, Chuanwei; Zhang, Yuxu; Cloquet, Christophe; Fan, Haifeng; Fu, Shaohong

    2016-04-28

    Lead-zinc deposits are often difficult to classify because clear criteria are lacking. In recent years, new tools, such as Cd and Zn isotopes, have been used to better understand the ore-formation processes and to classify Pb-Zn deposits. Herein, we investigate Cd concentrations, Cd isotope systematics and Zn/Cd ratios in sphalerite from nine Pb-Zn deposits divided into high-temperature systems (e.g., porphyry), low-temperature systems (e.g., Mississippi Valley type [MVT]) and exhalative systems (e.g., sedimentary exhalative [SEDEX]). Our results showed little evidence of fractionation in the high-temperature systems. In the low-temperature systems, Cd concentrations were the highest, but were also highly variable, a result consistent with the higher fractionation of Cd at low temperatures. The δ(114/110)Cd values in low-temperature systems were enriched in heavier isotopes (mean of 0.32 ± 0.31‰). Exhalative systems had the lowest Cd concentrations, with a mean δ(114/110)Cd value of 0.12 ± 0.50‰. We thus conclude that different ore-formation systems result in different characteristic Cd concentrations and fraction levels and that low-temperature processes lead to the most significant fractionation of Cd. Therefore, Cd distribution and isotopic studies can support better understanding of the geochemistry of ore-formation processes and the classification of Pb-Zn deposits.

  20. Lead isotope and trace element composition of urban soils in Mongolia

    Science.gov (United States)

    Tserenpil, Sh.; Sapkota, A.; Liu, C.-Q.; Peng, J.-H.; Liu, B.; Segebade, P. Chr.

    2016-08-01

    Lead (Pb) pollution in and around Ulaanbaatar is of national concern, given that the Mongolian capital is home to nearly half of the country's entire population. By comparison, Mongolian countryside is a pristine environment because of its sparse population and low industrial activity. The concentration of Pb in urban soils (average of 39.1 mg kg-1) was twice the values found (average 18.6 mg kg-1) in background territories (i.e., Mongolian rural sites). Furthermore, Pb contamination was examined by using Pb stable isotopic composition, and covariance of Pb isotopic ratios showed two groups between rural and urban soils as pristine and disturbed sites. The 206Pb/207Pb ratio, the most prominent fingerprint for Pb pollution, was 1.163-1.185 for the urban whereas values for rural soils (1.186-1.207) were analogue to the regional Pb isotopic signatures. Local coal sources and their combustion products, one of the potential Pb pollution sources in Ulaanbaatar, have significant radiogenic properties in terms of Pb isotopic composition and revealed an average of 1.25 for 206Pb/207Pb and 19.551 for 206Pb/204Pb ratios. Thus, contributions from coal firing activity to Pb pollution lower than it was assumed, and smaller range of these values measured in urban soils may be attributed to the mixing of less radiogenic Pb as a constituent of the leaded gasolines.

  1. Fluid flow along North American Cordillera detachments determined from stable isotope and high resolution chemical analyses

    Science.gov (United States)

    Quilichini, A.; Teyssier, C.; Mulch, A.; Nachlas, W.

    2009-12-01

    Fluid flow is likely a major parameter controlling the dynamics of extensional detachment zones. Buoyancy-driven fluid flow is generated by high heat flow beneath the detachment zone, where heat is advected by crustal thinning and magma intrusions. This hydrothermal convective flow is focused in the detachment zone for the duration of activity of the detachment at relatively high temperature (300-500°C), resulting in very significant fluid-rock interaction and isotopic exchange. Quantifying sources and fluid flux in detachments is a challenge because permeability of ductilely deforming rocks is poorly understood. In order to solve these problems, we studied two different Eocene extensional systems in the North American Cordillera: the quartzitic detachment which borders the Kettle dome metamorphic core complex (WA), and the quartzo-feldspathic Bitterroot shear zone along the Idaho batholith (MT). The Kettle Dome detachment provides a continuous section of ~200 m thick quartzite mylonite where high-resolution sampling (~5 m) indicates that Deuterium isotopic ratios that are obtained from synkinematic muscovite grains are consistent with a meteoric fluid source (-130 per mil). In the Bitterroot shear zone, Coyner (2003) reported similar Deuterium isotopic ratios (down to -140 per mil) in muscovite from mylonites and ultramylonites. Microprobe analyses were obtained for white mica porphyroclasts by performing transects perpendicular to the basal (001) cleavage in order to determine intragrain chemical zoning. Preliminary results for the Kettle dome indicate increasing phengite composition with depth, suggesting enhanced activity of the Tschermak exchange. The variations of the phengitic signature in muscovite indicates that temperature diminuish downsection, which is contradictory with the results obtained by the Qz-Ms oxygen isotope thermometer along the Kettle section. Our recent work provides geologic data for numerical models that address the permeability of

  2. Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

    Directory of Open Access Journals (Sweden)

    Christina Stantis

    Full Text Available The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP. The first burial mound (To-At-1 was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2 was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41 are used to asses paleodiet and 87Sr/86Sr ratios (n = 30 are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean. This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom.

  3. Determining the geographical origin of Chinese cabbages using multielement composition and strontium isotope ratio analyses.

    Science.gov (United States)

    Bong, Yeon-Sik; Shin, Woo-Jin; Gautam, Mukesh Kumar; Jeong, Youn-Joong; Lee, A-Reum; Jang, Chang-Soon; Lim, Yong-Pyo; Chung, Gong-Soo; Lee, Kwang-Sik

    2012-12-15

    Recently, the Korean market has seen many cases of Chinese cabbage (Brassica rapa ssp. pekinensis) that have been imported from China, yet are sold as a Korean product to illegally benefit from the price difference between the two products. This study aims to establish a method of distinguishing the geographical origin of Chinese cabbage. One hundred Chinese cabbage heads from Korea and 60 cabbage heads from China were subjected to multielement composition and strontium isotope ratio ((87)Sr/(86)Sr) analyses. The (87)Sr/(86)Sr ratio differed, based on the geological characteristics of their district of production. In addition, the content of many elements differed between cabbages from Korea and China. In particular, the difference in the content of Sr and Ti alone and the combination of Sr, Ca, and Mg allowed us to distinguish relatively well between Korea and China as the country of origin. The present study demonstrates that the chemical and Sr isotopic analyses exactly reflect the geology of the production areas of Chinese cabbage.

  4. Trophic positioning of meiofauna revealed by stable isotopes and food web analyses.

    Science.gov (United States)

    Schmid-Araya, Jenny M; Schmid, Peter E; Tod, Steven P; Esteban, Genoveva F

    2016-11-01

    Despite important advances in the ecology of river food webs, the strength and nature of the connection between the meio- and macrofaunal components of the web are still debated. Some unresolved issues are the effects of the inclusion of meiofaunal links and their temporal variations on the overall river food web properties, and the significance of autochthonous and allochthonous material for these components. In the present study, we conducted analyses of gut content of macro- and meiofauna and stable isotope analyses of meiofauna to examine seasonal food webs of a chalk stream. The results of the gut content analyses, confirmed by the δ(13) C signatures, revealed a seasonal shift from a dependence on autochthonous (biofilm) to allochthonous food sources. Here, we demonstrate that aggregating basal or meiofaunal species into single categories affects key web properties such as web size, links, linkage density, and predator-prey ratios. More importantly, seasonal variation in attributes characterized the entire web and these changes persist regardless of taxonomic resolution. Furthermore, our analyses evidenced discrete variations in δ(15) N across the meiofauna community with a trophic structure that confirms gut content analyses, placing the meiofauna high in the food web. We, therefore, conclude that small-body-sized taxa can occur high in dynamic river food webs, questioning assumptions that trophic position increases with body size and that webs are static. © 2016 by the Ecological Society of America.

  5. Lead isotope study of Zn-Pb ore deposits associated with the Basque-Cantabrian basin and Paleozoic basement, Northern Spain

    Science.gov (United States)

    Velasco, F.; Pesquera, A.; Herrero, J. M.

    1996-01-01

    A total of forty-three galena samples from syngenetic and epigenetic Pb-Zn mineralizations emplaced in the Lower Cretaceous Basque-Cantabrian basin and Paleozoic basement of the Cinco Villas massif in the western Pyrenees, have been analyzed for Pb-isotopic composition. Galena from sedex mineralizations hosted in Carboniferous clastic rocks in the Cinco Villas massif display an homogeneous lead isotopic signature (206Pb/2044Pb ≈ 18.43, 207Pb/204Pb ≈ 15.66, 208Pb/ 204Pb ≈ 38.69) suggesting a single lead reservoir. These values are slightly more radiogenic than lead from other European Hercynian deposits, possibly reflecting the influence of a more evolved upper crustal source. Underlying Paleozoic sediments are proposed as lead source for the Cinco Villas massif ores. Analyses from twenty-six galena samples from the four strata-bound ore districts hosted in Mesozoic rocks reveal the existence of two populations regarding their lead isotopic composition. Galena from the western Santander districts (e.g., Reocin) is characterized by more radiogenic isotope values (206Pb/204Pb ≈ 18.74, 207Pb/204Pb ≈ 15.67, 208Pb/ 204Pb ≈ 38.73) than those from the central and eastern districts (Troya-Legorreta, Central and Western Vizcaya, 206Pb/204Pb ≈ 18.59, 207Pb/204Pb ≈ 15.66, 208Pb/ 204Pb ≈ 38.73). In all districts, the most likely source for these mineralizations was the thick sequence of Lower Cretaceous clastic sediments. The existence of two separate lead isotopic populations could be the result of regional difference in the composition of the basement rocks and the clastic sediments derived of it or different evolution histories. In both sub-basins, isotopic ratios indicate an increase in crustal influence as the age of the ores decreases.

  6. Lead isotopic studies of lunar soils - Their bearing on the time scale of agglutinate formation

    Science.gov (United States)

    Church, S. E.; Tilton, G. R.; Chen, J. H.

    1976-01-01

    Fines (smaller than 75 microns) and bulk soil were studied to analyze loss of volatile lead; losses of the order of 10% to 30% radiogenic lead during the production of agglutinates are assessed. Lead isotope data from fine-agglutinate pairs are analyzed for information on the time scale of micrometeorite bombardment, from the chords generated by the data in concordia diagrams. Resulting mean lead loss ages were compared to spallogenic gas exposure ages for all samples. Labile parentless radiogenic Pb residing preferentially on or in the fines is viewed as possibly responsible for aberrant lead loss ages. Bulk soils plot above the concordia curve (in a field of excess radiogenic Pb) for all samples with anomalous ages.

  7. Copper and lead isotopic and metallic pollution record in soils from the Kombat mining area, Namibia

    Science.gov (United States)

    Mihaljevic, Martin; Ettler, Vojtech; Vanek, Ales; Chrastny, Vladislav; Kribek, Bohdan; Penizek, Vit; Sracek, Ondrej

    2013-04-01

    Copper (Cu) and lead (Pb) concentration, isotopic composition (206Pb/207Pb, 65Cu/63Cu) and speciation were studied in soils from the Kombat mining area. The Cu and Pb concentrations in the studied soils ranged between 21 mg/kg - 757 mg/kg, and 19 mg/kg - 815 mg/kg respectively. In the sequential extractions, the largest part of soil Cu appeared in the residual and reducible fractions and Pb was predominantly bound in reducible and residual fractions and was more mobile compared to Cu. Copper and Pb concentration are higher in soils close to the slime deposit. Concentration of both metals increased with increasing soil depth in irrigated and cultivated soils. In soils not contaminated by dust eroded from the slime deposit, Cu and Pb contents are not dependent on the soil depth. The Pb isotopic signatures (206Pb/207Pb) ranged between 1.15 - 1.21 in soils from the Kombat area. In most of soil samples, surface horizons exhibited lower 206Pb/207Pb ratio, which originates from the slime dust pollution (206Pb/207Pb ~ 1.15) compared to deeper soil horizons, with lithogenic Pb signatures (206Pb/207Pb > 1.2). Isotopic composition of Cu differs on contaminated and uncontaminated sites and cultivated and non-cultivated sites. The δ65Cu in the studied soil horizon ranged between -0.373 ‰ and 0.561 ‰. The most pronounced variations occurred in contaminated non cultivated and non-irrigated soils (0.529 ‰). The contaminated top horizons are enriched in isotopically heavier Cu (tailing materials), and δ65Cu decreased with depth. Irrigated (cultivated) and contaminated soils exhibited heavier Cu in the surface horizons (originated from tailing dust δ65Cu = 0.260), decrease of δ65Cu in Bt horizons (biological uptake of light isotope by crop, and their incorporation in this horizons) and increase of δ65Cu in Bc horizons. The Bc horizons of cultivated and irrigated Phaeozems are enriched in Mn nodules (0.2 - 1.5 cm diameter, prevailing Mn phase pyrochroite Mn(OH)2) which

  8. The Use of Lead Isotope and Rare Earth Element Geochemistry for Forensic Geographic Provenancing

    Science.gov (United States)

    Carey, A.; Darrah, T.; Harrold, Z.; Prutsman-Pfeiffer, J.; Poreda, R.

    2008-12-01

    Lead isotope and rare earth element composition of modern human bones are analyzed to explore their utility for geographical provenancing. DNA analysis is the standard for identification of individuals. DNA analysis requires a DNA match for comparison. Thus, DNA analysis is of limited use in cases involving unknown remains. Trace elements are incorporated into bones and teeth during biomineralization, recording the characteristics of an individual's geochemical environment. Teeth form during adolescence, recording the geochemical environment of an individual's youth. Bones remodel throughout an individual's lifetime. Bones consist of two types of bone tissue (cortical and trabecular) that remodel at different rates, recording the geochemical environment at the time of biomineralization. Cortical bone tissue, forming the outer surface of bones, is dense, hard tissue that remodels in 25-30 yrs. Conversely, trabecular bone tissue, the inner cavity of bones, is low density, porous and remodels in 2-5 years. Thus, analyzing teeth and both bone tissues allows for the development of a geographical time line capable of tracking immigration patterns through time instead of only an individual's youth. Geochemical isotopic techniques (Sr, O, C, N) have been used for geographical provenancing in physical anthropology. The isotopic values of Sr, C, O, N are predominantly a function of soil compositions in areas where food is grown or water is consumed. Application of these provenancing techniques has become difficult as an individual's diet may reflect the isotopic composition of foods obtained at the local grocer as opposed to local soil compositions. Thus, we explore the use of REEs and Pb isotopes for geographical provenancing. Pb and REEs are likely more reliable indicators of modern geographical location as their composition are high in bio-available sources such as local soils, atmospheric aerosols, and dust as opposed to Sr, C, O, N that are controlled by food and

  9. Simultaneous N, C, S isotopic analyses using purge and trap EA technology. Application to δ34S analyses of natural phosphate material NBS120c and BCR32

    Science.gov (United States)

    Fourel, F. P.; Lecuyer, C.; Martineau, F.

    2013-12-01

    The first example of stable isotope analyses in continuous flow mode by Preston et al in 19861 involved Elemental Analyser Isotopic Ratio Mass Spectrometry (EA-IRMS) dedicated to carbon isotopes in combustion mode. EA-IRMS has since then evolved to allow 34S/32S determinations still in combustion mode and mainly to access pyrolysis reaction for O and H isotopes. As far as combustion EA-IRMS is concerned the technique itself has remained unchanged since the development of 'purge and trap' separation techniques online with IRMS instruments. Here we have used a high-precision, easy, low-cost and rapid method of simultaneous carbon, nitrogen and sulphur isotope analysis using this new type of elemental analyser based on 'purge and trap' technology 2,3. Simultaneous determinations, performed on the same aliquot of 13C, 15N and 34S are demonstrated. Emphasis is put on the high quality of 34S/32S determinations. First concentrating on peak shapes, yields of conversion and preliminary results. Then the reliability and accuracy of such a technique is illustrated using analyses from various international reference materials. Alongside international reference material working NCS calibrated material has been selected and characterized prior to apply this technology to calibrate natural phosphate material used as compositional reference material BCR32 and NBS120c. δ34S values of respectively 15.62×0.32‰ and 16.5×0.17‰ are proposed for those samples with sulphur concentrations below the 1% level. The possibility to reliably measure S isotopes on that kind of samples opens up new fields of investigation especially for paleoenvironmental reconstructions. Keywords: carbon, nitrogen, sulfur, isotope, combustion, phosphate, elemental-analyser 1. T. Preston, N.J.P. Owens: Preliminary 13C Measurements using a Gas Chromatograph Interfaced to an Isotope Ratio Mass Spectrometer. Biomedical. Mass Spectrom. 1985, 12-9, 510. 2. H.P. Sieper, H.J. Kupka, L. Lange, A. Rossmann, N. Tanz

  10. Historical lead isotope record of a sediment core from the Derwent River (Tasmania, Australia): a multiple source environment.

    Science.gov (United States)

    Townsend, Ashley T; Seen, Andrew J

    2012-05-01

    A 105 cm sediment core from the Derwent River (Tasmania, Australia) was collected in 2004 and was characterised considering both physical (loss on ignition at 550 °C and grain size) and chemical (Fe, Cu, Zn, Cd and Pb concentrations, Pb isotope ratios and (210)Pb dating) properties. The core was analysed to (i) investigate the historical profiles of some important elements associated with the Risdon zinc refinery adjacent to the Derwent River, (ii) determine Pb isotopic signatures of sediment samples, and (iii) assess the veracity of Pb isotope ratios as indicators of contaminant Pb input. Extractable metal concentrations were (all values as mgkg(-1), non-normalised for grain size) Fe: 20,000-35,000, Zn: 42-4500, Pb: 5-1090, Cu: 13-141, and Cd: 1-31; with a close correlation between Cu, Zn, Cd and Pb. Metal enrichment factors (normalised to Al) were Pb: 0.9-144, Zn: 0.8-93, Cd: 0.8-30, Cu: 0.8-8.9 and Fe: 0.9-1.3, confirming anthropogenic contributions of Cu, Zn, Pb and Cd to the sediments. The onset of metal contamination above background levels occurred at a depth between 43 and 49 cm, with maximum concentrations noted near 20 cm for Cu, Zn, Cd and Pb. Lead isotope ratios were determined in sediments using sector field ICP-MS, and were found to be 36.5-38.8, 16.5-18.7 and 1.07-1.20 for (208)Pb/(204)Pb, (206)Pb/(204)Pb and (206)Pb/(207)Pb ratios, respectively. Major Australian ores processed at the refinery over the previous ~90 years include those from Broken Hill, Rosebery, Mt Isa, Elura, Hellyer and Century deposits. Anthropogenic impact by Pb with Broken Hill type isotopic ratio was initially evident in the core at 43-49 cm. The introduction of Rosebery and Elura ores to the refinery was also clearly noted. Pb isotope ratios further highlight that the Derwent River has been exposed to a greater impact by anthropogenic Pb in comparison to other major Tasmanian rivers, namely the Huon and Tamar.

  11. Neon isotopic composition of the mantle constrained by single vesicle analyses

    Science.gov (United States)

    Péron, Sandrine; Moreira, Manuel; Colin, Aurélia; Arbaret, Laurent; Putlitz, Benita; Kurz, Mark D.

    2016-09-01

    The origin of volatiles on Earth is still a matter of debate. Noble gases are an efficient geochemical tool to constrain Earth formation processes due to their inertness. Several studies have focused on the neon isotopic composition of the lower mantle because the 20Ne/22Ne ratio is thought to reflect that of Earth's primordial components. Two models to explain the origin of light noble gases on Earth have been proposed: either solar wind implantation onto the Earth's solid precursors or dissolution into the mantle of a primordial atmosphere captured from solar nebula gas. In order to test these two models, we analyzed the noble gas compositions (helium, neon and argon) of two submarine oceanic island basalt glasses from Fernandina volcano (Galápagos archipelago), which have among the most primitive/unradiogenic terrestrial helium and neon isotopic compositions. Several sample pieces are studied both by step-crushing and by laser ablation analyses of single vesicles. Results of step-crushing are consistent with those of laser ablation analyses, but the latter results provide new insights into the origin of atmospheric contamination. The single-vesicle laser-ablation measurements overlap with the step crushing results, but have systematically higher 40Ar/36Ar, and 3He/36Ar, suggesting less atmospheric contamination using this method. The single vesicle data therefore suggest that atmospheric contamination is introduced by exposure to the modern atmosphere, after sample collection. 3He/4He values are about 23 times the atmospheric ratio (R/Ra) for the two Fernandina (Galápagos) samples, in agreement with previous studies. We obtain 20Ne/22Ne and 40Ar/36Ar isotopic ratios as high as 12.91 and 9400, respectively, for the mantle source of the Galápagos hotspot. The new data show that step-crushing and laser ablation analyses are complementary methods that should be used together to derive the noble gas ratios in uncontaminated samples. The results of neon

  12. Re-evaluation of lead isotopic data, southern Massif Central, France

    Science.gov (United States)

    Sinclair, A. J.; Macquar, J. C.; Rouvier, H.

    1993-04-01

    Three independent Pb isotope homogenizing processes operating on large volumes of rock material during limited intervals in the Phanerozoic have been used to define a unique evolutionary curve for rock and ore lead isotopic compositions of the southern Massif Central, France. The model is 126_2004_Article_BF00196336_TeX2GIFE1.gif begin{gathered}{text{ x}}_{text{t}} = 18.641{text{ }} - {text{ 9}}{text{.56(e}}^{{text{L1*t}}} - 1{text{)}} {text{y}}_{text{t}} = 15.678{text{ }} - {text{ 0}}{text{.06934(e}}^{{text{L2*t}}} - 1{text{)}} {text{ z}}_{text{t}} = 38.701{text{ }} - {text{ 30}}{text{.8(e}}^{{text{L3*t}}} - 1{text{)}} where xt, yt and zt are the calculated isotopic ratios (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb respectively) at time t years ago and L1, L2 and L3 are the decay constants of 238U, 235U and 232Th respectively. The model gives the following ages for averages of the three sets of data used in its generation: age of mineralization for carbonate-hosted lead-zinc ore of Les Malines, ca. 150 Ma; emplacement of the Saint-Guiral-Liron granite, ca. 290 Ma; and an estimated average age of a group of Cambrian syngenetic deposits, ca. 520 Ma. These ages are in close agreement with ages determined by independent methods.

  13. The persistence of lead from past gasoline emissions and mining drainage in a large riparian system: Evidence from lead isotopes in the Sacramento River, California

    Science.gov (United States)

    Dunlap, C.E.; Alpers, C.N.; Bouse, R.; Taylor, H.E.; Unruh, D.M.; Flegal, A.R.

    2008-01-01

    Lead concentrations and isotope ratios measured in river water colloids and streambed sediment samples along 426 km of the Sacramento River, California reveal that the influence of lead from the historical mining of massive sulfide deposits in the West Shasta Cu-mining district (at the headwaters of the Sacramento River) is confined to a 60 km stretch of river immediately downstream of that mining region, whereas inputs from past leaded gasoline emissions and historical hydraulic Au-mining in the Sierra Nevadan foothills are the dominant lead sources in the remaining 370 km of the river. Binary mixing calculations suggest that more than 50% of the lead in the Sacramento River outside of the region of influence of the West Shasta Cu-mining district is derived from past depositions of leaded gasoline emissions. This predominance is the first direct documentation of the geographic extent of gasoline lead persistence throughout a large riparian system (>160,000 km2) and corroborates previous observations based on samples taken at the mouth of the Sacramento River. In addition, new analyses of sediment samples from the hydraulic gold mines of the Sierra Nevada foothills confirm the present-day fluxes into the Sacramento River of contaminant metals derived from historical hydraulic Au-mining that occurred during the latter half of the 19th and early part of the 20th centuries. These fluxes occur predominantly during periods of elevated river discharge associated with heavy winter precipitation in northern California. In the broadest context, the study demonstrates the potential for altered precipitation patterns resulting from climate change to affect the mobility and transport of soil-bound contaminants in the surface environment. ?? 2008 Elsevier Ltd.

  14. Stable isotope analyses reveal the importance of seagrass beds as feeding areas for juvenile Myrophic punctatus in Florida

    Science.gov (United States)

    The feeding habits and habitats of the speckled worm eel Myrophis punctatus were studied on the mangrove edge of the Indian River Lagoon (Florida) using stomach contents and stable isotope analyses of carbon (δ13C) and nitrogen (δ15N). Stomach dietary analyses identified four tax...

  15. Stable Isotope Analyses of Ancient Penguin Tissues Support the Krill Surplus Hypothesis in Antarctica

    Science.gov (United States)

    Emslie, S. D.; Polito, M. J.; Patterson, W. P.

    2010-12-01

    The krill surplus hypothesis in Antarctica is based on the premise that historic depletion of krill-eating whales and seals in the 18-20th centuries provided a surplus of krill in the southern ocean that benefited penguins. Previous study of δ13C and δ15N stable isotopes in ancient and modern tissues of Adélie Penguin (Pygoscelis adeliae) from dozens of active and abandoned colonies in Antarctica have provided the first test in support of this hypothesis (Emslie and Patterson 2007). Specifically, there is a significant decrease in both δ13C and δ15N isotope values in modern versus ancient Adélie Penguin tissues from an apparent dietary shift from fish to krill associated with the timing of the purported krill surplus. Here, we present new data on similar analyses of Gentoo Penguin (P. papua) tissues from active and abandoned colonies at two locations in the Antarctic Peninsula to determine if this species recorded a similar shift in its diet in association with the krill surplus. Our results demonstrate a significant decrease (1.5-2.0 ‰) in δ13C in modern versus fossil eggshells (two-tailed t-test of modern versus fossil mean values, t = 1.98, p Proceedings of the National Academy of Sciences 104: 11666-11669. A pair of Adélie Penguins with their well-fed chick.

  16. CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767.

    Science.gov (United States)

    Assonov, S S; Brenninkmeijer, C A M; Koeppel, C; Röckmann, T

    2009-03-01

    Analytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft-based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and isotopic composition. In the laboratory, an ultra-pure and high efficiency extraction system and high-quality isotope ratio mass spectrometry were used. Because direct comparison with other laboratories was practically impossible, the extraction and measurement procedures were tested in considerable detail. Extracted CO2 was measured twice vs. two different working reference CO2 gases of different isotopic composition. The two data sets agree well and their distributions can be used to evaluate analytical errors due to isotope measurement, ion corrections, internal calibration consistency, etc. The calibration itself is based on NBS-19 and also verified using isotope analyses on pure CO2 gases (NIST Reference Materials (RMs) and NARCIS CO2 gases). The major problem encountered could be attributed to CO2-water exchange in the air sampling cylinders. This exchange decreased over the years. To exclude artefacts due to such isotopic exchange, the data were filtered to reject negative delta18O(CO2) values. Examples of the results are given.

  17. Lead Isotopes and Temporal Records of Atmospheric Aerosol and Pollutants in Lichens

    Science.gov (United States)

    Getty, S. R.; Nash, T.; Asmerom, Y.

    2001-05-01

    Lichens are useful receptors of atmospheric particulate matter (PM) and pollutants due to their retention of body parts (unlike plants), slow growth rates, fairly uniform morphologies, lack of a vascular system, and sessile character over decades to centuries. Lichen biomonitoring has been used widely to map patterns of aerosol deposition, yet few studies have tested whether lichens can preserve a temporal record of airborne PM and pollutants. We show with U-Pb data that epilithic lichens (rock as host) can retain in their porous structure an integrated, decadal-scale history of changing aerosol inputs to desert ecosystems. Three lichens resided along an 80-km transect from a copper smelter (Douglas, AZ) closed in early 1987, to the ENE into adjacent New Mexico. For the radially growing lichen (Xanthoparmelia sp.), U-Pb data were obtained along cm-scale transects in the growth direction on a single thallus. Profiles from lichen rim to interior show increasing [Pb] and [U], or net accumulation with thallus age. Total lead contents are highest near the smelter. In contrast, each lead isotope profile (206Pb/207Pb) is flat during smelter operation, showing low ratios near the smelter (1.152) and high ratios (1.175) 80 km away. This suggests comparable mixtures of crust and smelter lead per locality over decades. Since smelter closure, lichens 80 km from the smelter show a sharp upturn in lead ratio in the recently grown lichen rim, indicating that smelter lead is either dispersed by aeolian recycling, or suppressed in desert soils. The amplitude and position of the isotope signal suggests a soil recovery "half-life" of about 13 yrs, a radial growth rate of 0.57+/-0.1 mm/yr, and a total lichen age of 105+/-18 yrs. Lichens near the smelter have no upturn in isotope ratio, indicating continued aeolian recylcing of lead from soils about 11 yrs after closure. Results at a far-removed desert site (c. New Mexico) also argue that isotope profiles reflect aerosol deposition

  18. Application of tree-ring isotopic analyses to reconstruct historical water use of riparian trees.

    Science.gov (United States)

    Alstad, Karrin P; Hart, Stephen C; Horton, Jonathan L; Kolb, Thomas E

    2008-03-01

    Historical patterns of water source use by trees inferred from long-term records of tree-ring stable isotopic content could assist in evaluating the impact of human alterations to natural stream flow regimes (e.g., water impoundments, stream flow diversions, and groundwater extraction). Our objective was to assess the utility of the hydrogen stable isotopic composition (SD) of tree rings as an index of historical water source use by riparian trees. We investigated the influence of site conditions that varied in climate and hydrology on the relationship between deltaD of Populus xylem water (deltaD(xyl)) and tree-ring cellulose (deltaD(cell)). deltaD(xyl) and deltaD(cell) were strongly correlated across sites (r2 = 0.89). However, the slope of this relationship was less than 1, indicating that factors other than deltaD(xyl) influenced deltaD(cell). Inverse modeling with an isotopic fractionation model for tree-ring cellulose suggested that the lack of one-to-one correspondence between deltaD(xyl) and deltaD(cell) was due to the influence of the hydrogen isotopic content of the atmospheric water vapor (deltaD(atm)). Empirically measured values of deltaD(cell) were typically within the seasonal range of deltaD(cell) predicted from the fractionation model. Sensitivity analyses showed that changes in deltaD(xyl) generally had a greater influence at high-elevation montane sites, whereas deltaD(xyl) and deltaD(atm) had about equal influence on deltaD(cell) at low-elevation desert sites. The intrasite relationship between deltaD(cell) and deltaD(xyl) among individual trees was poor, perhaps because of the within-site spatial variation in hydrologic conditions and associated tree physiological responses. Our study suggests that historical variation in deltaD(cell) of Populus provides information on historical variation in both time-integrated water source use and atmospheric conditions; and that the influence of atmospheric conditions is not consistent over sites with large

  19. Potential of Opuntia ficus-indica for air pollution biomonitoring: a lead isotopic study.

    Science.gov (United States)

    El Hayek, Eliane; El Samrani, Antoine; Lartiges, Bruno; Kazpard, Veronique; Benoit, Mathieu; Munoz, Marguerite

    2015-11-01

    Opuntia ficus-indica (Ofi) is a long-domesticated cactus that is widespread throughout arid and semiarid regions. Ofi is grown for both its fruits and edible cladodes, which are flattened photosynthetic stems. Young cladodes develop from mother cladodes, thus forming series of cladodes of different ages. Therefore, successive cladodes may hold some potential for biomonitoring over several years the local atmospheric pollution. In this study, cladodes, roots, dust deposited onto the cladodes, and soil samples were collected in the vicinity of three heavily polluted sites, i.e., a fertilizer industry, the road side of a highway, and mine tailings. The lead content was analyzed using atomic absorption spectroscopy (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) was used to characterize the cladode surfaces and the nature of dust deposit, and the lead isotopes were analyzed to identify the origin of Pb. The results show that (i) Ofi readily bioaccumulates Pb, (ii) the lead isotopic composition of cladodes evidences a foliar pathway of lead into Ofi and identifies the relative contributions of local Pb sources, and (iii) an evolution of air quality is recorded with successive cladodes, which makes Ofi a potential biomonitor to be used in environmental and health studies.

  20. Drought Impacts on Ancient Maya Maize Agriculture Inferred from Isotopic Analyses of Plant Biomarkers

    Science.gov (United States)

    Douglas, P. M.; Pagani, M.; Eglinton, T. I.; Brenner, M.; Hodell, D. A.; Curtis, J. H.

    2013-05-01

    There is increasing evidence suggesting that a series of droughts in the Maya lowlands of southeastern Mexico and northern Central America coincided with the Terminal Classic decline of the Classic Maya civilization (ca. 1250 to 1000 years BP). However, there is little evidence directly linking climatic change and changes in human activities in this region. In this study we combine plant-wax hydrogen and carbon analyses in two lake sediment cores from the Yucatan and northern Guatemala to develop coupled records of hydroclimate variability and human-driven vegetation change and assess drought impacts on maize agriculture In the Maya lowlands plant-wax hydrogen isotope ratios (δD) are controlled by the isotopic composition of precipitation and evapotranspiration, and are highly sensitive to changes in aridity. In this low-elevation tropical environment plant-wax carbon isotope ratios (δ13C) are largely controlled by the relative abundance of C3 and C4 plants. The ancient Maya practiced widespread maize (C4) agriculture and strongly influenced regional C3-C4 vegetation dynamics. Under natural conditions C4 plant coverage and plant-wax δD would tend to co-vary positively since C4 plants are well adapted for dry conditions. Under ancient Maya land-use, however, this relationship is likely to be decoupled, since drought would have disrupted C4 agriculture. Combined analyses of plant-wax δD and δ13C from two lake sediment cores in the Maya lowlands indicate co-evolving changes in hydroclimate and C4 plant coverage over the past 4000 years. Compound-specific radiocarbon analyses of plant-waxes provide independent chronologies for these plant-wax stable isotope records, and plant-wax δD records developed using these chronologies agree closely with other regional records of hydroclimate change. Trends in plant-wax δD and δ13C diverge following ca. 3500 years BP, around the onset of widespread ancient Maya agriculture. After this time high plant-wax δD values tend

  1. Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

    Science.gov (United States)

    Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

    2012-12-01

    Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

  2. Using a laser-based CO2 carbon isotope analyser to investigate gas transfer in geological media

    Science.gov (United States)

    Guillon, S.; Pili, E.; Agrinier, P.

    2012-05-01

    CO2 stable carbon isotopes are very attractive in environmental research to investigate both natural and anthropogenic carbon sources. Laser-based CO2 carbon isotope analysis provides continuous measurement at high temporal resolution and is a promising alternative to isotope ratio mass spectrometry (IRMS). We performed a thorough assessment of a commercially available CO2 Carbon Isotope Analyser (CCIA DLT-100, Los Gatos Research) that allows in situ measurement of δ 13C in CO2. Using a set of reference gases of known CO2 concentration and carbon isotopic composition, we evaluated the precision, long-term stability, temperature sensitivity and concentration dependence of the analyser. Despite good precision calculated from Allan variance (5.0 ppm for CO2 concentration, and 0.05 ‰ for δ 13C at 60 s averaging), real performances are altered by two main sources of error: temperature sensitivity and dependence of δ 13C on CO2 concentration. Data processing is required to correct for these errors. Following application of these corrections, we achieve an accuracy of 8.7 ppm for CO2 concentration and 1.3 ‰ for δ 13C, which is worse compared to mass spectrometry performance, but still allowing field applications. With this portable analyser we measured CO2 flux degassed from rock in an underground tunnel. The obtained carbon isotopic composition agrees with IRMS measurement, and can be used to identify the carbon source.

  3. Pb isotope geochemistry of lead, zinc, gold and silver deposit clustered region, Liaodong rift zone,northeastern China

    Institute of Scientific and Technical Information of China (English)

    CHEN; Jiangfeng; YU; Gang; XUE; Chunji; QIAN; Hui; HE; Jian

    2005-01-01

    33 Pb isotopic analyses were reported for sulfide and hydrothermal carbonate minerals and marble of the Xiquegou lead-zinc, the Zhenzigou zinc-lead and the Gaojiapuzi silver deposits from the Qingchengzi ore field and the Beiwagou zinc-lead deposit in the west, Proterozoic Liaodong rift zone. Pb isotopic ratios of the marble from the Qingchengzi ore field range from 18.24 to 30.63 for 206Pb/204Pb, 15.59 to 17.05 for 207Pb/204Pb and 37.43 to 38.63 for 208Pb/204Pb. The marble gives a Pb-Pb isochron age of 1822±92 Ma, which is interpreted as the age of the metamorphism of the marble. Ore Pb, including Pb of sulfide and hydrothermal carbonate minerals, from the Qingchengzi ore field shows limited variation with 206Pb/204Pb=17.66-17.96, 207Pb/204Pb=15.60-15.74 and 208Pb/204Pb=37.94-38.60. In contrast, ore Pb from the Beiwagou deposit gives different Pb isotopic ratios with 206Pb/204Pb=15.68-15.81, 207Pb/204Pb= 15.34-15.45 and 208Pb/204Pb=35.30-35.68. Pb of all deposits from the Liaodong rift zone is derived from the upper crust. Ore Pb of the Qingchengzi deposits is derived from a young upper crust. The model Th/U ratios of 4.40 to 4.74 for ore Pb are significantly different from that of 1.7 to 4.4 given by the marble of the Qingchengzi ore field, suggesting that marble is not the source of the ore Pb. Ore Pb of the Beiwagou deposit is extracted from its source and the deposit is formed at the Paleoproterozoic era. Different Pb isotopic ratios of the Qingchengzi ore field and the Beiwagou deposit are due to different ages of the deposits and suggest that the two types of deposits are derived from different sources and are possibly formed by different ore-forming processes.

  4. Using trace element content and lead isotopic composition to assess sources of PM in Tijuana, Mexico

    Science.gov (United States)

    Salcedo, D.; Castro, T.; Bernal, J. P.; Almanza-Veloz, V.; Zavala, M.; González-Castillo, E.; Saavedra, M. I.; Perez-Arvízu, O.; Díaz-Trujillo, G. C.; Molina, L. T.

    2016-05-01

    PM2.5 samples were collected at two urban sites (Parque Morelos (PQM) and CECyTE (CEC)) in Tijuana during the Cal-Mex campaign from May 24 to June 5, 2010. Concentration of trace elements (Mg, Al, Ti, V, Mn, Fe, Co, Ni, Zn, Cu, Ga, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Ba, La, Ce, and Pb), and Pb isotopic composition were determined in order to study the sources of PM impacting each site. Other chemical analysis (gravimetric, elemental and organic carbon (EC/OC), and polycyclic aromatic hydrocarbons (PAHs)), were also performed. Finally, back-trajectories were calculated to facilitate the interpretation of the chemical data. Trace elements results show that CEC is a receptor site affected by mixed regional sources: sea salt, mineral, urban, and industrial. On the other hand, PQM seems to be impacted mainly by local sources. In particular, Pb at CEC is of anthropogenic, as well as crustal origin. This conclusion is supported by the lead isotopic composition, whose values are consistent with a combination of lead extracted from US mines, and lead from bedrocks in the Mexican Sierras. Some of the time variability observed can be explained using the back-trajectories.

  5. GCM Analysis of the collective properties of lead isotopes with exact projection on particle numbers

    CERN Document Server

    Heenen, P H; Bender, M; Bonche, P; Flocard, Hubert

    2001-01-01

    We present a microscopic analysis of the collective behaviour of the lead isotopes in the vicinity of Pb208. In this study, we rely on a coherent approach based on the Generator Coordinate Method including exact projection on N and Z numbers within a collective space generated by means of the constrained Hartree-Fock BCS method. With the same Hamiltonian used in HF+BCS calculations, we have performed a comprehensive study including monopole, quadrupole and octupole excitations as well as pairing vibrations. We find that, for the considered nuclei, the collective modes which modify the most the conclusions drawn from the mean-field theory are the octupole and pairing vibrations.

  6. Evidence for in-situ methane production in ice based on anomalous isotope analyses

    Science.gov (United States)

    Sowers, T. A.; Priscu, J.

    2004-12-01

    the Sajama ice core from central Bolivia (18oS, 69oW, 6542masl), for example, were 1X-5X higher than contemporaneous values recorded in polar ice cores [Campen et al., 2003]. \\delta13CH4 values from five discrete depths were compared to corresponding measurements made on the Taylor Dome ice core and suggest the additional (in-situ) CH_{4} in the Sajama samples has an average isotopic composition of -63.2±2.8‰ . For reference, atmospheric δ ^{13}CH_{4} values range from -42 to -45/pm over this period. The Sajama isotope values are characteristic of methanogenic CH_{4} emitted from most terrestrial ecosystems. The second case study revolves around ice that was recovered from a perennially ice covered lake in the McMurdo Dry Valleys, Antarctica. Previous work on ice from Lake Bonney demonstrated a rich microbial consortium located ~2m below the surface [Priscu et al., 1998]. Methane isotope analyses were made on ice from this depth interval to identify the presence of microbially produced CH_{4}. δ ^{13}CH_{4} and δ DCH4 results suggest the CH4 arises from acetogenic CH4 production as opposed to CO2 reduction. Campen, R.K., T. Sowers, and R.B. Alley, Evidence of Microbial Consortia Metabolizing Within a Low-Latitude Mountain Glacier, Geology, 31 (No. 3), 231-234, 2003. Priscu, J.C., et al., Perennial Antarctic Lake Ice: An oasis for life in a polar desert, Science, 280, 2095-2098, 1998.

  7. Formation of black and white smokers in the North Fiji Basin: Sulfur and lead isotope constraints

    Science.gov (United States)

    Kim, J.; Lee, I.; Lee, K.; Yoo, C.; Ko, Y.

    2004-12-01

    The hydrothermal chimneys were recovered from 16o50¡_S triple junction area in the North Fiji Basin. The chimney samples are divided into three groups according to their mineralogy and metal contents; 1) Black smoker, 2) White smoker, 3) Transitional type. Black smoker chimneys are mainly composed of chalcopyrite and pyrite, and are enriched in high temperature elements such as Cu, Co, Mo, and Se. White smoker chimneys consist of sphalerite and marcasite with trace of pyrite and chalcopyrite, and are enriched in low temperature elements (Zn, Cd, Pb, As, and Ga). Transitional chimneys show intermediate characteristics in mineralogy and composition between black and white smokers. Basaltic rocks sampled from the triple junction show wide variation in geochemistry. Trace elements composition of basaltic rocks indicates that the magma genesis in the triple junction area was affected by mixing between N-MORB and E-MORB sources. The sulfur and lead isotope compositions of hydrothermal chimneys show distinct differences between the black and white smokers. Black smokers are depleted in 34S (Øä34S = +0.4 to +4.8) and are low in lead isotope composition (206Pb/204Pb = 18.082 to 18.132; 207Pb/204Pb = 15.440 to 15.481; 208Pb/204Pb = 37.764 to 37.916) compared to white smoker and transitional chimneys (Øä34S = +2.4 to +5.6; 206Pb/204Pb = 18.122 to 18.193; 207Pb/204Pb = 15.475 to 15.554; 208Pb/204Pb = 37.882 to 38.150). The heavier sulfur isotopic fractionation in white smoker can be explained by boiling of hydrothermal fluids and mixing with ambient seawater. The lead isotope compositions of the hydrothermal chimneys indicate that the metal in black and white smokers come from hydrothermal reaction with N-MORB and E-MORB, respectively. Regarding both black and white smoker are located in the same site, the condition of phase separation of hydrothermal fluid that formed white smokers might result from P-T condition of high temperature reaction zone below the hydrothermal

  8. Fracture mechanics analyses of the slip-side joggle regions of wing-leading-edge panels

    Directory of Open Access Journals (Sweden)

    Kyongchan Song

    2011-01-01

    Full Text Available The Space Shuttle wing-leading edge consists of panels that are made of reinforced carbon-carbon. Coating spallation was observed near the slip-side region of the panels that experience extreme heating. To understand this phenomenon, a root-cause investigation was conducted. As part of that investigation, fracture mechanics analyses of the slip-side joggle regions of the hot panels were conducted. This paper presents an overview of the fracture mechanics analyses.

  9. Fracture Mechanics Analyses of the Slip-Side Joggle Regions of Wing-Leading-Edge Panels

    Science.gov (United States)

    Raju, Ivatury S.; Knight, Norman F., Jr.; Song, Kyongchan; Phillips, Dawn R.

    2011-01-01

    The Space Shuttle wing-leading edge consists of panels that are made of reinforced carbon-carbon. Coating spallation was observed near the slip-side region of the panels that experience extreme heating. To understand this phenomenon, a root-cause investigation was conducted. As part of that investigation, fracture mechanics analyses of the slip-side joggle regions of the hot panels were conducted. This paper presents an overview of the fracture mechanics analyses.

  10. Lead isotopic composition and lead source of the Tongchanghe basalt-type native copper-chalcocite deposit in Ninglang, western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; ZHU Xiaoqing; ZHANG Zhengwei

    2006-01-01

    The Tongchanghe native copper-chalcocite deposit at Ninglang occurs in low-Ti basalts of western Yunnan, and the mode of fault-filling & metasomatism metallogenesis indicates that this deposit is of late-stage hydrothermal origin. This makes it more complicated to define the source of ore-forming materials. This paper introduces the Pb isotope data of Himalayan alkali-rich porphyries, regional Early-Middle Proterozoic metamorphic rock basement and various types of rocks of the mining district in western Yunnan with an attempt to constrain the origin of the Tongchanghe native copper-chalcocite deposit at Ninglang.The results showed that the ores are relatively homogeneous in Pb isotopic composition, implying a simple ore-forming material source. The three sets of Pb isotopic ratios in the Himalayan alkali-rich porphyries are all higher than those of the ores; the regional basement metamorphic rocks show a wide range of variations in Pb isotopic ratio, quite different from the isotopic composition of ore lead; the Pb isotopic composition of the Triassic sedimentary rocks and mudstone and siltstone interbeds in the Late Permian Heinishao Formation (corresponding to the forth cycle of basaltic eruption) in the mining district has the characteristics of radiogenic lead and is significantly different from the isotopic composition of ore lead; like the ores, the Emeishan basalts in the mining district and those regionally distributed possess the same Pb isotopic composition, showing a complete overlap with respect to their distribution range. From the above, the possibilities can be ruled out that the ore-forming materials of the Tongchanghe deposit were derived from the basement, a variety of Himalayan magmatic activities, etc. It is thereby defined that the ore-forming materials were derived largely from the Emeishan basalts. From the data available it is deduced that the native cupper-chalcocite-type metallogenesis that occurred in the Emeishan basalt-distributed area

  11. Quality Assessment of Meta-analyses Published in Leading Anesthesiology Journals From 2005 to 2014.

    Science.gov (United States)

    Hall, Amber M; Lee, Sandra; Zurakowski, David

    2017-06-01

    Meta-analysis, when preceded by a systematic review, is considered the "gold standard" in data aggregation; however, the quality of meta-analyses is often questionable, leading to uncertainty about the accuracy of results. In this study, we evaluate the quality of meta-analyses published in 5 leading anesthesiology journals from 2005 to 2014. A total of 220 meta-analyses published in Anesthesiology, Pain, British Journal of Anaesthesia, Anaesthesia, or Anesthesia & Analgesia were identified for inclusion. The quality of each meta-analysis was determined using the Revised Assessment of Multiple Systematic Reviews (R-AMSTAR). R-AMSTAR rated 11 questions related to systematic reviews and meta-analyses on a scale of 1-4, with 4 representing the highest quality. Overall meta-analyses quality was evaluated using a Spearmen regression analysis and found to positively correlate with time (rs = 0.24, P leading anesthesiology journals has increased over the last decade. Furthermore, assessing the scientific quality of included studies in meta-analyses (P = .60) and using this assessment to formulate conclusions and/or recommendations (P = .67) remains relatively low (median R-AMSTAR: 2, interquartile range [IQR]: 2-3]; median R-AMSTAR: 2, IQR: 1-2, respectively).

  12. Spectral analysis software improves confidence in plant and soil water stable isotope analyses performed by isotope ratio infrared spectroscopy (IRIS).

    Science.gov (United States)

    West, A G; Goldsmith, G R; Matimati, I; Dawson, T E

    2011-08-30

    Previous studies have demonstrated the potential for large errors to occur when analyzing waters containing organic contaminants using isotope ratio infrared spectroscopy (IRIS). In an attempt to address this problem, IRIS manufacturers now provide post-processing spectral analysis software capable of identifying samples with the types of spectral interference that compromises their stable isotope analysis. Here we report two independent tests of this post-processing spectral analysis software on two IRIS systems, OA-ICOS (Los Gatos Research Inc.) and WS-CRDS (Picarro Inc.). Following a similar methodology to a previous study, we cryogenically extracted plant leaf water and soil water and measured the δ(2)H and δ(18)O values of identical samples by isotope ratio mass spectrometry (IRMS) and IRIS. As an additional test, we analyzed plant stem waters and tap waters by IRMS and IRIS in an independent laboratory. For all tests we assumed that the IRMS value represented the "true" value against which we could compare the stable isotope results from the IRIS methods. Samples showing significant deviations from the IRMS value (>2σ) were considered to be contaminated and representative of spectral interference in the IRIS measurement. Over the two studies, 83% of plant species were considered contaminated on OA-ICOS and 58% on WS-CRDS. Post-analysis, spectra were analyzed using the manufacturer's spectral analysis software, in order to see if the software correctly identified contaminated samples. In our tests the software performed well, identifying all the samples with major errors. However, some false negatives indicate that user evaluation and testing of the software are necessary. Repeat sampling of plants showed considerable variation in the discrepancies between IRIS and IRMS. As such, we recommend that spectral analysis of IRIS data must be incorporated into standard post-processing routines. Furthermore, we suggest that the results from spectral analysis be

  13. Holocene elemental, lead isotope and charcoal record from peat in southern Poland

    Directory of Open Access Journals (Sweden)

    K. Tudyka

    2017-03-01

    Full Text Available This article presents a mid-resolution elemental, isotopic and charcoal record from 10700 BC to AD 500 in a peat core located in Żyglin (southern Poland. The objective is to give insight into the proxies with emphasis on lead (Pb sources in this minerogenic peat deposit. During the Early Holocene (10700–7550 BC the average 206Pb/207Pb quotient was around 1.196. This isotopic signature is consistent with natural dust derived from long-distance soil and rock weathering. The Mid-Holocene period (7550–3200 BC shows a significant change in the peat accumulation conditions. The growth rate is approximately 0.04 mm yr-1 and the 206Pb/207Pb quotients are shifted toward values that are found in local galena ores. This is simultaneous with a significantly increased lead flux which further confirms local sources of material in this peat deposit. In the Late Holocene period (3200 BC–AD 500 a large quantity of charcoal particles with diameters ranging from 2 mm up to 3 cm is found; also, Pb, Zn and Cu fluxes reach their highest values. This period corresponds to the Eneolithic, Bronze and Iron Ages, and human impact is recorded as charcoal.

  14. {ital E}3 transition probabilities in the platinum, mercury, and lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Egido, J.L.; Martin, V.; Robledo, L.M.; Sun, Y. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)]|[Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660 Madrid (Spain)]|[Department of Physics and Atmospheric Science, Drexel University, Philadelphia, Pennsylvania 19104 (United States)]|[Joint Institute for Heavy Ion Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    1996-06-01

    Spectroscopical properties of the platinum, mercury, and lead isotopes are studied within the Hartree-Fock plus BCS framework with the finite range density-dependent Gogny force. These properties are also studied beyond mean-field theory by combining the use of generator-coordinate-method-like wave functions with the angular momentum projection technique as to generate many-body correlated wave functions that are at the same time eigenstates of the angular momentum operator. We apply this formalism to the calculation of reduced transition probabilities {ital B}({ital E}3) from the lowest-lying octupole collective state to the ground state of several isotopes of the platinum, mercury, and lead nuclei whose experimental {ital B}({ital E}3) values present a peculiar behavior. The projected calculations show a large improvement over the unprojected ones when compared with the experimental data. The unprojected calculations are unable to predict any structure in the {ital B}({ital E}3). {copyright} {ital 1996 The American Physical Society.}

  15. Comparison of lead isotopes with source apportionment models, including SOM, for air particulates.

    Science.gov (United States)

    Gulson, Brian; Korsch, Michael; Dickson, Bruce; Cohen, David; Mizon, Karen; Davis, J Michael

    2007-08-01

    We have measured high precision lead isotopes in PM(2.5) particulates from a highly-trafficked site (Mascot) and rural site (Richmond) in the Sydney Basin, New South Wales, Australia to compare with isotopic data from total suspended particulates (TSP) from other sites in the Sydney Basin and evaluate relationships with source fingerprints obtained from multi-element PM(2.5) data. The isotopic data for the period 1998 to 2004 show seasonal peaks and troughs that are more pronounced in the rural site for the PM(2.5).samples but are consistent with the TSP. The Self Organising Map (SOM) method has been applied to the multi-element PM(2.5) data to evaluate its use in obtaining fingerprints for comparison with standard statistical procedures (ANSTO model). As seasonal effects are also significant for the multi-element data, the SOM modelling is reported as site and season dependent. At the Mascot site, the ANSTO model exhibits decreasing (206)Pb/(204)Pb ratios with increasing contributions of fingerprints for "secondary smoke" (industry), "soil", "smoke" and "seaspray". Similar patterns were shown by SOM winter fingerprints for both sites. At the rural site, there are large isotopic variations but for the majority of samples these are not associated with increased contributions from the main sources with the ANSTO model. For two winter sampling times, there are increased contributions from "secondary industry", "smoke", "soil" and seaspray with one time having a source or sources of Pb similar to that of Mascot. The only positive relationship between increasing (206)Pb/(204)Pb ratio and source contributions is found at the rural site using the SOM summer fingerprints, both of which show a significant contribution from sulphur. Several of the fingerprints using either model have significant contributions from black carbon (BC) and/or sulphur (S) that probably derive from diesel fuels and industrial sources. Increased contributions from sources with the SOM summer

  16. Impact on the environment from steel bridge paint deterioration using lead isotopic tracing, paint compositions and soil deconstruction.

    Science.gov (United States)

    Gulson, Brian; Chiaradia, Massimo; Davis, Jeffrey; O'Connor, Gary

    2016-04-15

    Deterioration and repair of lead paint on steel structures can result in contamination of the ambient environment but other sources of lead such as from past use of leaded paint and gasoline and industrial activities can also contribute to the contamination. Using a combination of high precision lead isotopic tracing, detailed paint examination, including with scanning electron microscopy, and soil deconstruction we have compared paint on a steel bridge and bulk soil and lead-rich particles separated from soil. The majority of Pb found in the paint derives from Australian sources but some also has a probable US origin. The isotopic data for the bulk soils and selected particles lie on a mixing line with end members the geologically ancient Broken Hill lead and possible European lead which is suggested to be derived from old lead paint and industrial activities. Data for gasoline-derived particulates lie on this array and probably contribute to soil Pb. Although paint from the bridge can be a source of lead in the soils, isotopic tracing, paint morphology and mineralogical identification indicate that other sources, including from paint, gasoline and industrial activities, are contributing factors to the lead burden. Even though physical characteristics and elemental composition are the same in some particles, the isotopic signatures demonstrate that the sources are different. Plots using (206)Pb/(208)Pb vs (206)Pb/(207)Pb ratios, the common representation these days, do not allow for source discrimination in this investigation.

  17. Thermal Safety Analyses for the Production of Plutonium-238 at the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hurt, Christopher J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Freels, James D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hobbs, Randy W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jain, Prashant K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Maldonado, G. Ivan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    There has been a considerable effort over the previous few years to demonstrate and optimize the production of plutonium-238 (238Pu) at the High Flux Isotope Reactor (HFIR). This effort has involved resources from multiple divisions and facilities at the Oak Ridge National Laboratory (ORNL) to demonstrate the fabrication, irradiation, and chemical processing of targets containing neptunium-237 (237Np) dioxide (NpO2)/aluminum (Al) cermet pellets. A critical preliminary step to irradiation at the HFIR is to demonstrate the safety of the target under irradiation via documented experiment safety analyses. The steady-state thermal safety analyses of the target are simulated in a finite element model with the COMSOL Multiphysics code that determines, among other crucial parameters, the limiting maximum temperature in the target. Safety analysis efforts for this model discussed in the present report include: (1) initial modeling of single and reduced-length pellet capsules in order to generate an experimental knowledge base that incorporate initial non-linear contact heat transfer and fission gas equations, (2) modeling efforts for prototypical designs of partially loaded and fully loaded targets using limited available knowledge of fabrication and irradiation characteristics, and (3) the most recent and comprehensive modeling effort of a fully coupled thermo-mechanical approach over the entire fully loaded target domain incorporating burn-up dependent irradiation behavior and measured target and pellet properties, hereafter referred to as the production model. These models are used to conservatively determine several important steady-state parameters including target stresses and temperatures, the limiting condition of which is the maximum temperature with respect to the melting point. The single pellet model results provide a basis for the safety of the irradiations, followed by parametric analyses in the initial prototypical designs

  18. Historical lead isotope record of a sediment core from the Derwent River (Tasmania, Australia): A multiple source environment

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Ashley T., E-mail: Ashley.Townsend@utas.edu.au [Central Science Laboratory, University of Tasmania, Private Bag 74, Hobart, Tasmania 7001 (Australia); Seen, Andrew J. [School of Chemistry, University of Tasmania, Locked Bag 1371, Launceston, Tasmania 7250 (Australia)

    2012-05-01

    A 105 cm sediment core from the Derwent River (Tasmania, Australia) was collected in 2004 and was characterised considering both physical (loss on ignition at 550 Degree-Sign C and grain size) and chemical (Fe, Cu, Zn, Cd and Pb concentrations, Pb isotope ratios and {sup 210}Pb dating) properties. The core was analysed to (i) investigate the historical profiles of some important elements associated with the Risdon zinc refinery adjacent to the Derwent River, (ii) determine Pb isotopic signatures of sediment samples, and (iii) assess the veracity of Pb isotope ratios as indicators of contaminant Pb input. Extractable metal concentrations were (all values as mg kg{sup -1}, non-normalised for grain size) Fe: 20,000-35,000, Zn: 42-4500, Pb: 5-1090, Cu: 13-141, and Cd: 1-31; with a close correlation between Cu, Zn, Cd and Pb. Metal enrichment factors (normalised to Al) were Pb: 0.9-144, Zn: 0.8-93, Cd: 0.8-30, Cu: 0.8-8.9 and Fe: 0.9-1.3, confirming anthropogenic contributions of Cu, Zn, Pb and Cd to the sediments. The onset of metal contamination above background levels occurred at a depth between 43 and 49 cm, with maximum concentrations noted near 20 cm for Cu, Zn, Cd and Pb. Lead isotope ratios were determined in sediments using sector field ICP-MS, and were found to be 36.5-38.8, 16.5-18.7 and 1.07-1.20 for {sup 208}Pb/{sup 204}Pb, {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb ratios, respectively. Major Australian ores processed at the refinery over the previous {approx} 90 years include those from Broken Hill, Rosebery, Mt Isa, Elura, Hellyer and Century deposits. Anthropogenic impact by Pb with Broken Hill type isotopic ratio was initially evident in the core at 43-49 cm. The introduction of Rosebery and Elura ores to the refinery was also clearly noted. Pb isotope ratios further highlight that the Derwent River has been exposed to a greater impact by anthropogenic Pb in comparison to other major Tasmanian rivers, namely the Huon and Tamar. - Highlights

  19. CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767

    NARCIS (Netherlands)

    Assonov, S.S.; Brenninkmeijer, C.A.M.; Koeppel, C.; Röckmann, T.

    2009-01-01

    Analytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft-based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and

  20. A summary of two meta-analyses on neurobehavioural effects due to occupational lead exposure

    Energy Technology Data Exchange (ETDEWEB)

    Seeber, Andreas; Meyer-Baron, Monika; Schaeper, Michael [Institut fuer Arbeitsphysiologie, Universitaet Dortmund (Germany)

    2002-04-01

    The conclusions from published results about neurotoxic effects of inorganic lead exposures <700 {mu}g lead/l blood are contradictory at present. Effects measured by neurobehavioural methods are evaluated differently as far as recommendations for a Biological Exposure Index (BEI) of occupational lead exposure are concerned. Arguments against the German BEI of 400 {mu}g/l were put forward in new publications, and discussion of the issues is the aim of this article. It summarizes two different meta-analytical reviews on neurobehavioural effects in order to show the main tendencies of 24 selected publications on the matter. Calculations on effect sizes are compiled for 12 tests analysed in two meta-analyses and of ten tests analysed in one of the meta-analyses. The survey of six tests of learning and memory gives hints on impairments measured with two tests, covering Logical Memory and Visual Reproduction. The survey of seven tests of attention and visuospatial information processing describes impairments in four tests, namely Simple Reaction, Attention Test d2, Block Design, and Picture Completion. The survey of four tests for psychomotor functions shows impairments for three tests, namely Santa Ana, Grooved Pegboard, and Eye-hand Coordination. These test results provide evidence for subtle deficits being associated with average blood lead levels between 370 and 520 {mu}g/l. In evaluating the adversity of such effects it is concluded that the results of both meta-analytical reviews support the recommendation for the German BEI. (orig.)

  1. Investigations on the use of anodic stripping voltammetry for the analyses of lead in saline environments

    Energy Technology Data Exchange (ETDEWEB)

    Case, C.W.

    1978-08-01

    Research is reported directed to modification of the anodic stripping voltammetry (ASV) analytic method in order to acquire data for lead from ambient sea water conditions, and development of a chemical model which uses these data to identify inorganic lead species for saline environments. Laboratory and field samples were analyzed for lead partitioning in: (a) KCl electrolyte solutions; (b) I.A.P.S.O. Standard Sea Water; (c) seawater samples from Quatsino Sound, British Columbia; (d) a series of seawater samples from San Francisco Bay; and (e) seawater samples from the Gulf of Mexico. The electrochemical traits of the lead species and the ASV oxidation potential expression are the fundamental constituents of the chemical model. The model uses the data from the analyses to provide the mass balance relationships for lead partitioned among the major anions in seawater. The laboratory analyses of KCl electrolyte and Standard Seawater give the following results. The modified ASV method and chemical model provide information on ambient labile and non-labile inorganic lead complexes in these saline solutions down to the parts-per-billion level. No purge and the simple electrodes cause some erratic behavior and spurious potentials, but the data are reproducible. In addition to Pb/sup 2 +/, the most dominant measured lead species in order include PbCO/sub 3//sup 0/, PbSO/sub 4//sup 0/, PbCl/sup +/, and Pb(NO/sub 3/)/sub 2//sup 0/ from the lead additions solution. The analyses of the field samples give the following results. Samples were taken from the partially anoxic basin in Quatsino Sound, British Columbia with one successful analysis which is for somewhat normal dissolved oxygen conditions. Data show that lead is partitioned among Pb/sup 2 +/, Pb(OH)/sub 2//sup 0/, PbCO/sub 3//sup 0/, and PbSO/sub 4//sup 0/. The analyses with purge for the San Francisco Bay water partitions lead among Pb/sup 2 +/, PbCO/sub 3//sup 0/, PbSO/sub 4//sup 0/, PbCl/sup +/, and Pb

  2. Lead concentrations and isotope ratios in street dust determined by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Nageotte, S M; Day, J P

    1998-01-01

    A major source of environmental lead, particularly in urban areas, has been from the combustion of leaded petrol. Street dust has previously been used to assess urban lead contamination, and the dust itself can also be a potential source of lead ingestion, particularly to children. The progressive reduction of lead in petrol, in recent years, would be expected to have been reflected in a reduction of lead in urban dust. We have tested this hypothesis by repeating an earlier survey of Manchester street dust and carrying out a comparable survey in Paris. Samples were collected from streets and parks, lead was extracted by digestion with concentrated nitric acid and determined by electrothermal atomic absorption spectrometry. Lead isotope ratios were measured by inductively coupled plasma mass spectrometry. Results for Manchester show that lead concentrations have fallen by about 40% (street dust averages, 941 micrograms g-1 (ppm) in 1975 down to 569 ppm in 1997). In Paris, the lead levels in street dust are much higher and significant differences were observed between types of street (not seen in Manchester). Additionally, lead levels in parks were much lower than in Manchester. Samples collected under the Eiffel Tower had very high concentrations and lead isotope ratios showed that this was unlikely to be fallout from motor vehicles but could be due to the paint used on the tower. Isotope ratios measurements also revealed that lead additives used in France and the UK come from different sources.

  3. Stable isotope analyses of web-spinning spider assemblages along a headwater stream in Puerto Rico.

    Science.gov (United States)

    Kelly, Sean P; Cuevas, Elvira; Ramírez, Alonso

    2015-01-01

    Web-spinning spiders that inhabit stream channels are considered specialists of aquatic ecosystems and are major consumers of emerging aquatic insects, while other spider taxa are more commonly found in riparian forests and as a result may consume more terrestrial insects. To determine if there was a difference in spider taxa abundance between riverine web-spinning spider assemblages within the stream channel and the assemblages 10 m into the riparian forest, we compared abundances for all web-spinning spiders along a headwater stream in El Yunque National Forest in northeast Puerto Rico. By using a nonmetric dimensional scaling (NMDS) abundance analysis we were able to see a clear separation of the two spider assemblages. The second objective of the study was to determine if aquatic insects contributed more to the diet of the spider assemblages closest to the stream channel and therefore stable isotope analyses of δ (15)N and δ (13)C for web-spinning spiders along with their possible prey were utilized. The results of the Bayesian mixing model (SIAR) however showed little difference in the diets of riverine (0 m), riparian (10 m) and upland (25 m) spiders. We found that aquatic insects made up ∼50% of the diet for web-spinning spiders collected at 0 m, 10 m, and 25 m from the stream. This study highlights the importance of aquatic insects as a food source for web-spinning spiders despite the taxonomic differences in assemblages at different distances from the stream.

  4. Stable isotope analyses of web-spinning spider assemblages along a headwater stream in Puerto Rico

    Directory of Open Access Journals (Sweden)

    Sean P. Kelly

    2015-10-01

    Full Text Available Web-spinning spiders that inhabit stream channels are considered specialists of aquatic ecosystems and are major consumers of emerging aquatic insects, while other spider taxa are more commonly found in riparian forests and as a result may consume more terrestrial insects. To determine if there was a difference in spider taxa abundance between riverine web-spinning spider assemblages within the stream channel and the assemblages 10 m into the riparian forest, we compared abundances for all web-spinning spiders along a headwater stream in El Yunque National Forest in northeast Puerto Rico. By using a nonmetric dimensional scaling (NMDS abundance analysis we were able to see a clear separation of the two spider assemblages. The second objective of the study was to determine if aquatic insects contributed more to the diet of the spider assemblages closest to the stream channel and therefore stable isotope analyses of δ15N and δ13C for web-spinning spiders along with their possible prey were utilized. The results of the Bayesian mixing model (SIAR however showed little difference in the diets of riverine (0 m, riparian (10 m and upland (25 m spiders. We found that aquatic insects made up ∼50% of the diet for web-spinning spiders collected at 0 m, 10 m, and 25 m from the stream. This study highlights the importance of aquatic insects as a food source for web-spinning spiders despite the taxonomic differences in assemblages at different distances from the stream.

  5. Characterization of rapeseed (Brassica napus) oils by bulk C, O, H, and fatty acid C stable isotope analyses.

    Science.gov (United States)

    Richter, Eva Katharina; Spangenberg, Jorge E; Kreuzer, Michael; Leiber, Florian

    2010-07-14

    Rapeseed ( Brassica napus ) oils differing in cultivar, sites of growth, and harvest year were characterized by fatty acid concentrations and carbon, hydrogen, and oxygen stable isotope analyses of bulk oils (delta(13)C(bulk), delta(2)H(bulk), delta(18)O(bulk) values) and individual fatty acids (delta(13)C(FA)). The delta(13)C(bulk), delta(2)H(bulk), and delta(18)O(bulk) values were determined by continuous flow combustion and high-temperature conversion elemental analyzer-isotope ratio mass spectrometry (EA/IRMS, TC-EA/IRMS). The delta(13)C(FA) values were determined using gas chromatography--combustion-isotope ratio mass spectrometry (GC/C/IRMS). For comparison, other C(3) vegetable oils rich in linolenic acid (flax and false flax oils) and rich in linoleic acid (poppy, sunflower, and safflower oils) were submitted to the same chemical and isotopic analyses. The bulk and molecular delta(13)C values were typical for C(3) plants. The delta(13)C value of palmitic acid (delta(13)C(16:0)) and n-3 alpha-linolenic acid (delta(13)C(18:3n-3)) differed (p oils. Also within species, significant differences of delta(13)C(FA) were observed (p oil differed between cultivars (p oil and specific fatty acid stable isotope analysis might be useful in tracing dietary lipids differing in their origin.

  6. A lead isotope study of mineralization in the Saudi Arabian Shield

    Science.gov (United States)

    Stacey, J.S.; Doe, B.R.; Roberts, R.J.; Delevaux, M.H.; Gramlich, J.W.

    1980-01-01

    New lead isotope data are presented for some late Precambrian and early Paleozoic vein and massive sulfide deposits in the Arabian Shield. Using the Stacey Kramers (1975) model for lead isotope evolution, isochron model ages range between 720 m.y. and 420 m.y. Most of the massive sulfide deposits in the region formed before 680 m.y. ago, during evolution of the shield. Vein type mineralization of higher lead content occurred during the Pan African event about 550 m.y. ago and continued through the Najd period of extensive faulting in the shield that ended about 530 m.y. ago. Late post-tectonic metamorphism may have been responsible for vein deposits that have model ages less than 500 m.y. Alternatively some of these younger model ages may be too low due to the mineralizing fluids acquiring radiogenic lead from appreciably older local crustal rocks at the time of ore formation. The low207Pb/204Pb ratios found for the deposits in the main part of the shield and for those in north-eastern Egypt, indicate that the Arabian craton was formed in an oceanic crustal environment during the late Precambrian. Involvement of older, upper-crustal material in the formation of the ore deposits in this part of the shield is precluded by their low207Pb/204Pb and208Pb/204Pb characteristics. In the eastern part of the shield, east of longitude 44??20???E towards the Al Amar-Idsas fault region, lead data are quite different. They exhibit a linear207Pb/204Pb-206Pb/204Pb relationship together with distinctly higher208Pb/204Pb characteristics. These data imply the existence of lower crustal rocks of early Proterozoic age that apparently have underthrust the shield rocks from the east. If most of the samples we have analyzed from this easterly region were mineralized 530 m.y. ago, then the age of the older continental rocks is 2,100??300 m.y. (2??). The presence of upper crustal rocks, possibly also of early Proterozoic age, is indicated by galena data from Hailan in South Yemen and also

  7. Integrating stomach content and stable isotope analyses to quantify the diets of pygoscelid penguins.

    Directory of Open Access Journals (Sweden)

    Michael J Polito

    Full Text Available Stomach content analysis (SCA and more recently stable isotope analysis (SIA integrated with isotopic mixing models have become common methods for dietary studies and provide insight into the foraging ecology of seabirds. However, both methods have drawbacks and biases that may result in difficulties in quantifying inter-annual and species-specific differences in diets. We used these two methods to simultaneously quantify the chick-rearing diet of Chinstrap (Pygoscelis antarctica and Gentoo (P. papua penguins and highlight methods of integrating SCA data to increase accuracy of diet composition estimates using SIA. SCA biomass estimates were highly variable and underestimated the importance of soft-bodied prey such as fish. Two-source, isotopic mixing model predictions were less variable and identified inter-annual and species-specific differences in the relative amounts of fish and krill in penguin diets not readily apparent using SCA. In contrast, multi-source isotopic mixing models had difficulty estimating the dietary contribution of fish species occupying similar trophic levels without refinement using SCA-derived otolith data. Overall, our ability to track inter-annual and species-specific differences in penguin diets using SIA was enhanced by integrating SCA data to isotopic mixing modes in three ways: 1 selecting appropriate prey sources, 2 weighting combinations of isotopically similar prey in two-source mixing models and 3 refining predicted contributions of isotopically similar prey in multi-source models.

  8. Fluid flow in extensional detachments determined from stable isotope analyses: Application to Kettle dome detachment, Washington, USA

    Science.gov (United States)

    Quilichini, A.; Teyssier, C.; Mulch, A.; Nachlas, W.

    2009-04-01

    In detachment systems that border metamorphic core complexes fluids convect from the surface to the detachment along faults and fractures in the brittle crust that serve as zones of recharge and discharge. This buoyancy-driven fluid flow is controlled by a high heat flow at the base of the system, beneath the detachment, where heat is advected by crustal thinning and magma intrusions. This hydrothermal convective flow is focused in the detachment for the duration of activity of the detachment and at relatively high temperature (300-500°C), resulting in very significant fluid-rock interaction and isotopic exchange. Studies of detachments in the North American Cordilleran core complexes suggest that meteoric fluids permeate detachment zones, as recorded by the deuterium composition of hydrous phases such as white mica, biotite, and amphibole. Quantifying fluid flux in detachments is a challenge because permeability of ductilely deforming rocks is poorly understood. The approach we are using focuses on oxygen and hydrogen isotopes in quartzite (+ minor mica) sections of detachments, complemented by high-precision chemical analyses of mica to understand their growth history and recrystallization process. The initial fluid isotopic composition is approximated using the deuterium composition of mica at a particular temperature that is given by oxygen isotopes in quartz-mica pairs. The more fluid interact with the quartzite, the larger the expected shift in oxygen isotope value. The Eocene Kettle Dome detachment in the North American Cordillera provides a continuous section of ~200 m thick quartzite mylonite where this methodology is applied. High-resolution sampling (up to 5 m) complements the initial sampling that was performed every 10 m in this section (Mulch et al., 2006, Tectonics, TC4001). Based on mica deuterium values, the fluid that participated in mica crystallization was meteoric in origin (~110 per mil). Interaction of this fluid with the quartz mylonite

  9. Middle Pleistocene ecology and Neanderthal subsistence: insights from stable isotope analyses in Payre (Ardèche, southeastern France).

    Science.gov (United States)

    Ecker, Michaela; Bocherens, Hervé; Julien, Marie-Anne; Rivals, Florent; Raynal, Jean-Paul; Moncel, Marie-Hélène

    2013-10-01

    The Middle Palaeolithic site of Payre in southeastern France yields abundant archaeological material associated with fossil hominid remains. With its long sequence of Middle Pleistocene deposits, Payre is a key site to study the Middle Palaeolithic chronology of this region. This study is the first to investigate carbon and oxygen isotope contents of Neanderthal tooth enamel bioapatite, together with a wide range of herbivorous and carnivorous species. The aim is to contribute to the understanding of hunting behaviour, resource partitioning, diet and habitat use of animals and Neanderthals through a palaeoecological reconstruction. Local topography had a visible influence on carbon and oxygen stable isotope values recorded in herbivore tooth enamel. This was used to investigate possible habitats of herbivores. The different herbivorous species do not show large variations of their carbon and oxygen isotope values through time, indicating niche conservatism from OIS 8-7 to OIS 6-5, i.e., independently of palaeoclimatic and palaeoenvironmental variations. Based on these new observations, we conclude that Neanderthals employed a stable subsistence strategy over time, using a variety of local resources, with resource partitioning visible between humans and carnivores, especially wolves. A comparison of the results of stable isotopic investigation with the results of tooth wear analyses previously conducted on the same teeth allowed us to demonstrate that grazing and browsing do not bind animals to a specific habitat in a C3 environment as reflected in the isotopic values.

  10. Impact of historical mining assessed in soils by kinetic extraction and lead isotopic ratios

    Energy Technology Data Exchange (ETDEWEB)

    Camizuli, E., E-mail: estelle.camizuli@u-bourgogne.fr [UMR 6298, ArTeHiS, Université de Bourgogne — CNRS — Culture, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon (France); Monna, F. [UMR 6298, ArTeHiS, Université de Bourgogne — CNRS — Culture, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon (France); Bermond, A.; Manouchehri, N.; Besançon, S. [Institut des sciences et industries du vivant et de l' environnement (AgroParisTech), Laboratoire de Chimie Analytique, 16, rue Claude Bernard, 75231 Paris Cedex 05 (France); Losno, R. [UMR 7583, LISA, Universités Paris 7-Paris 12 — CNRS, 61 av. du Gal de Gaulle, 94010 Créteil Cedex (France); Oort, F. van [UR 251, Pessac, Institut National de la Recherche Agronomique, Centre de Versailles-Grignon, RD 10, 78026 Versailles Cedex (France); Labanowski, J. [UMR 7285, IC2MP, Université de Poitiers — CNRS, 4, rue Michel Brunet, 86022 Poitiers (France); Perreira, A. [UMR 6298, ArTeHiS, Université de Bourgogne — CNRS — Culture, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon (France); Chateau, C. [UFR SVTE, Université de Bourgogne, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon (France); Alibert, P. [UMR 6282, Biogeosciences, Université de Bourgogne — CNRS, 6 bd Gabriel, Bat. Gabriel, 21000 Dijon (France)

    2014-02-01

    The aim of this study is to estimate the long-term behaviour of trace metals, in two soils differently impacted by past mining. Topsoils from two 1 km{sup 2} zones in the forested Morvan massif (France) were sampled to assess the spatial distribution of Cd, Cu, Pb and Zn. The first zone had been contaminated by historical mining. As expected, it exhibits higher trace-metal levels and greater spatial heterogeneity than the second non-contaminated zone, supposed to represent the local background. One soil profile from each zone was investigated in detail to estimate metal behaviour, and hence, bioavailability. Kinetic extractions were performed using EDTA on three samples: the A horizon from both soil profiles and the B horizon from the contaminated soil. For all three samples, kinetic extractions can be modelled by two first-order reactions. Similar kinetic behaviour was observed for all metals, but more metal was extracted from the contaminated A horizon than from the B horizon. More surprising is the general predominance of the residual fraction over the “labile” and “less labile” pools. Past anthropogenic inputs may have percolated over time through the soil profiles because of acidic pH conditions. Stable organo-metallic complexes may also have been formed over time, reducing metal availability. These processes are not mutually exclusive. After kinetic extraction, the lead isotopic compositions of the samples exhibited different signatures, related to contamination history and intrinsic soil parameters. However, no variation in lead signature was observed during the extraction experiment, demonstrating that the “labile” and “less labile” lead pools do not differ in terms of origin. Even if trace metals resulting from past mining and metallurgy persist in soils long after these activities have ceased, kinetic extractions suggest that metals, at least for these particular forest soils, do not represent a threat for biota. - Highlights: • Trace

  11. Benchmark of SCALE (SAS2H) isotopic predictions of depletion analyses for San Onofre PWR MOX fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, O.W.

    2000-02-01

    The isotopic composition of mixed-oxide (MOX) fuel, fabricated with both uranium and plutonium, after discharge from reactors is of significant interest to the Fissile Materials Disposition Program. The validation of the SCALE (SAS2H) depletion code for use in the prediction of isotopic compositions of MOX fuel, similar to previous validation studies on uranium-only fueled reactors, has corresponding significance. The EEI-Westinghouse Plutonium Recycle Demonstration Program examined the use of MOX fuel in the San Onofre PWR, Unit 1, during cycles 2 and 3. Isotopic analyses of the MOX spent fuel were conducted on 13 actinides and {sup 148}Nd by either mass or alpha spectrometry. Six fuel pellet samples were taken from four different fuel pins of an irradiated MOX assembly. The measured actinide inventories from those samples has been used to benchmark SAS2H for MOX fuel applications. The average percentage differences in the code results compared with the measurement were {minus}0.9% for {sup 235}U and 5.2% for {sup 239}Pu. The differences for most of the isotopes were significantly larger than in the cases for uranium-only fueled reactors. In general, comparisons of code results with alpha spectrometer data had extreme differences, although the differences in the calculations compared with mass spectrometer analyses were not extremely larger than that of uranium-only fueled reactors. This benchmark study should be useful in estimating uncertainties of inventory, criticality and dose calculations of MOX spent fuel.

  12. Fracture Mechanics Analyses of Reinforced Carbon-Carbon Wing-Leading-Edge Panels

    Science.gov (United States)

    Raju, Ivatury S.; Phillips, Dawn R.; Knight, Norman F., Jr.; Song, Kyongchan

    2010-01-01

    Fracture mechanics analyses of subsurface defects within the joggle regions of the Space Shuttle wing-leading-edge RCC panels are performed. A 2D plane strain idealized joggle finite element model is developed to study the fracture behavior of the panels for three distinct loading conditions - lift-off and ascent, on-orbit, and entry. For lift-off and ascent, an estimated bounding aerodynamic pressure load is used for the analyses, while for on-orbit and entry, thermo-mechanical analyses are performed using the extreme cold and hot temperatures experienced by the panels. In addition, a best estimate for the material stress-free temperature is used in the thermo-mechanical analyses. In the finite element models, the substrate and coating are modeled separately as two distinct materials. Subsurface defects are introduced at the coating-substrate interface and within the substrate. The objective of the fracture mechanics analyses is to evaluate the defect driving forces, which are characterized by the strain energy release rates, and determine if defects can become unstable for each of the loading conditions.

  13. Isotopically constrained lead sources in fugitive dust from unsurfaced roads in the southeast Missouri mining district

    Science.gov (United States)

    Witt, Emitt C.; Pribil, Michael; Hogan, John P; Wronkiewicz, David

    2016-01-01

    The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using 207Pb/206Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the 207Pb/206Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb-impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and 207Pb/206Pb of mining area dust suggest that 35.4–84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1–52.7% is associated with the smelter mixture, and 0–21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe + Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil.

  14. Isotopically constrained lead sources in fugitive dust from unsurfaced roads in the southeast Missouri mining district.

    Science.gov (United States)

    Witt, Emitt C; Pribil, Michael J; Hogan, John P; Wronkiewicz, David J

    2016-09-01

    The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using (207)Pb/(206)Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the (207)Pb/(206)Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb-impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and (207)Pb/(206)Pb of mining area dust suggest that 35.4-84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1-52.7% is associated with the smelter mixture, and 0-21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe + Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil.

  15. Use of Lead Isotopes to Identify Sources of Metal and Metalloid Contaminants in Atmospheric Aerosol from Mining Operations

    Science.gov (United States)

    Félix, Omar I.; Csavina, Janae; Field, Jason; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.

    2014-01-01

    Mining operations are a potential source of metal and metalloid contamination by atmospheric particulate generated from smelting activities, as well as from erosion of mine tailings. In this work, we show how lead isotopes can be used for source apportionment of metal and metalloid contaminants from the site of an active copper mine. Analysis of atmospheric aerosol shows two distinct isotopic signatures: one prevalent in fine particles (< 1 μm aerodynamic diameter) while the other corresponds to coarse particles as well as particles in all size ranges from a nearby urban environment. The lead isotopic ratios found in the fine particles are equal to those of the mine that provides the ore to the smelter. Topsoil samples at the mining site show concentrations of Pb and As decreasing with distance from the smelter. Isotopic ratios for the sample closest to the smelter (650 m) and from topsoil at all sample locations, extending to more than 1 km from the smelter, were similar to those found in fine particles in atmospheric dust. The results validate the use of lead isotope signatures for source apportionment of metal and metalloid contaminants transported by atmospheric particulate. PMID:25496740

  16. Application of carbon and hydrogen stable isotope analyses to detect exogenous citric acid in Japanese apricot liqueur.

    Science.gov (United States)

    Akamatsu, Fumikazu; Oe, Takaaki; Hashiguchi, Tomokazu; Hisatsune, Yuri; Kawao, Takafumi; Fujii, Tsutomu

    2017-08-01

    Japanese apricot liqueur manufacturers are required to control the quality and authenticity of their liqueur products. Citric acid made from corn is the main acidulant used in commercial liqueurs. In this study, we conducted spiking experiments and carbon and hydrogen stable isotope analyses to detect exogenous citric acid used as an acidulant in Japanese apricot liqueurs. Our results showed that the δ(13)C values detected exogenous citric acid originating from C4 plants but not from C3 plants. The δ(2)H values of citric acid decreased as the amount of citric acid added increased, whether the citric acid originated from C3 or C4 plants. Commercial liqueurs with declared added acidulant provided higher δ(13)C values and lower δ(2)H values than did authentic liqueurs and commercial liqueurs with no declared added acidulant. Carbon and hydrogen stable isotope analyses are suitable as routine methods for detecting exogenous citric acid in Japanese apricot liqueur.

  17. Evidence for Patterns of Selective Urban Migration in the Greater Indus Valley (2600-1900 BC: A Lead and Strontium Isotope Mortuary Analysis.

    Directory of Open Access Journals (Sweden)

    Benjamin Valentine

    Full Text Available Just as modern nation-states struggle to manage the cultural and economic impacts of migration, ancient civilizations dealt with similar external pressures and set policies to regulate people's movements. In one of the earliest urban societies, the Indus Civilization, mechanisms linking city populations to hinterland groups remain enigmatic in the absence of written documents. However, isotopic data from human tooth enamel associated with Harappa Phase (2600-1900 BC cemetery burials at Harappa (Pakistan and Farmana (India provide individual biogeochemical life histories of migration. Strontium and lead isotope ratios allow us to reinterpret the Indus tradition of cemetery inhumation as part of a specific and highly regulated institution of migration. Intra-individual isotopic shifts are consistent with immigration from resource-rich hinterlands during childhood. Furthermore, mortuary populations formed over hundreds of years and composed almost entirely of first-generation immigrants suggest that inhumation was the final step in a process linking certain urban Indus communities to diverse hinterland groups. Additional multi disciplinary analyses are warranted to confirm inferred patterns of Indus mobility, but the available isotopic data suggest that efforts to classify and regulate human movement in the ancient Indus region likely helped structure socioeconomic integration across an ethnically diverse landscape.

  18. Evidence for Patterns of Selective Urban Migration in the Greater Indus Valley (2600-1900 BC): A Lead and Strontium Isotope Mortuary Analysis

    Science.gov (United States)

    Valentine, Benjamin; Kamenov, George D.; Kenoyer, Jonathan Mark; Shinde, Vasant; Mushrif-Tripathy, Veena; Otarola-Castillo, Erik; Krigbaum, John

    2015-01-01

    Just as modern nation-states struggle to manage the cultural and economic impacts of migration, ancient civilizations dealt with similar external pressures and set policies to regulate people’s movements. In one of the earliest urban societies, the Indus Civilization, mechanisms linking city populations to hinterland groups remain enigmatic in the absence of written documents. However, isotopic data from human tooth enamel associated with Harappa Phase (2600-1900 BC) cemetery burials at Harappa (Pakistan) and Farmana (India) provide individual biogeochemical life histories of migration. Strontium and lead isotope ratios allow us to reinterpret the Indus tradition of cemetery inhumation as part of a specific and highly regulated institution of migration. Intra-individual isotopic shifts are consistent with immigration from resource-rich hinterlands during childhood. Furthermore, mortuary populations formed over hundreds of years and composed almost entirely of first-generation immigrants suggest that inhumation was the final step in a process linking certain urban Indus communities to diverse hinterland groups. Additional multi disciplinary analyses are warranted to confirm inferred patterns of Indus mobility, but the available isotopic data suggest that efforts to classify and regulate human movement in the ancient Indus region likely helped structure socioeconomic integration across an ethnically diverse landscape. PMID:25923705

  19. Suggested protocol for collecting, handling and preparing peat cores and peat samples for physical, chemical, mineralogical and isotopic analyses.

    Science.gov (United States)

    Givelet, Nicolas; Le Roux, Gaël; Cheburkin, Andriy; Chen, Bin; Frank, Jutta; Goodsite, Michael E; Kempter, Heike; Krachler, Michael; Noernberg, Tommy; Rausch, Nicole; Rheinberger, Stefan; Roos-Barraclough, Fiona; Sapkota, Atindra; Scholz, Christian; Shotyk, William

    2004-05-01

    elements have led to the development of many analytical procedures which now permit the measurement of a wide range of elements in peat samples such as lead and lead isotope ratios, mercury, arsenic, antimony, silver, molybdenum, thorium, uranium, rare earth elements. Radiometric methods (the carbon bomb pulse of (14)C, (210)Pb and conventional (14)C dating) are combined to allow reliable age-depth models to be reconstructed for each peat profile.

  20. The lead (Pb) isotope signature, behaviour and fate of traffic-related lead pollution in roadside soils in The Netherlands

    NARCIS (Netherlands)

    Walraven, N.; van Os, B.J.H.; Klaver, G.Th.; Middelburg, J.J.; Davies, G.R.

    2014-01-01

    In this study the origin, behaviour and fate of anthropogenic Pb in sandy roadside soils were assessed by measuring soil characteristics, Pb isotope composition and content. In 1991 and 2003 samples were taken at different depth intervals at approximately 8 and 75 m from two highways in The

  1. Isotopic equilibration between dissolved and suspended particulate lead in the Atlantic Ocean - Evidence from Pb-210 and stable Pb isotopes

    Science.gov (United States)

    Sherrell, Robert M.; Boyle, Edward A.; Hamelin, Bruno

    1992-01-01

    Vertical profiles of, on one hand, the stable Pb isotopic composition, and on the other, the ratio of total Pb to Pb-210 in suspended particles, are noted to closely track contemporaneous depth variations in these ratios for dissolved Pb throughout the upper 2 km of the Sargasso Sea near Bermuda. A simple flux model suggests that the effect of deep ocean scavenging processes on the flux and isotopic composition of Pb sinking on large particles was minor throughout the preanthropogenic, and most of the anthropogenic era: but it has become more important as surface inputs decrease to preleaded gasoline levels, perhaps exceeding the contribution of surface-derived Pb flux in the next decade.

  2. Status on DEMO Helium Cooled Lithium Lead breeding blanket thermo-mechanical analyses

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, J., E-mail: julien.aubert@cea.fr [CEA-Saclay, DEN, DM2S, F-91191 Gif-sur-Yvette (France); Aiello, G.; Jaboulay, J.-C. [CEA-Saclay, DEN, DM2S, F-91191 Gif-sur-Yvette (France); Kiss, B. [Institute of Nuclear Techniques, Budapest University of Technology and Economics, Budapest (Hungary); Morin, A. [CEA-Saclay, DEN, DM2S, F-91191 Gif-sur-Yvette (France)

    2016-11-01

    Highlights: • CEA with the support of Wigner-RCP and IPP-CR, is in charge of the design of the HCLL blanket for DEMO. The DEMO HCLL breeding blanket design capitalizes on the experience acquired on the HCLL Test Blanket Module designed for ITER. Design improvements are being implemented to adapt the design to DEMO specifications and performance objectives. • Thermal and mechanical analyses have been carried out in order to justify the design of the HCLL breeding blanket showing promising results for tie rods modules’ attachments system and relatively good behavior of the box in case of LOCA when comparing to RCC-MRx criteria. • CFD thermal analyses on generic breeding unit have enabled the consolidation of the results obtained with previous FEM design analyses. - Abstract: The EUROfusion Consortium develops a design of a fusion power demonstrator (DEMO) in the framework of the European “Horizon 2020” innovation and research program. One of the key components in the fusion reactor is the breeding blanket surrounding the plasma, ensuring tritium self-sufficiency, heat removal for conversion into electricity, and neutron shielding. The Helium Cooled Lithium Lead (HCLL) blanket is one of the concepts which is investigated for DEMO. It is made of a Eurofer structure and uses the eutectic liquid lithium–lead as tritium breeder and neutron multiplier, and helium gas as coolant. Within the EUROfusion organization, CEA with the support of Wigner-RCP and IPP-CR, is in charge of the design of the HCLL blanket for DEMO. This paper presents the status of the thermal and mechanical analyses carried out on the HCLL breeding blanket in order to justify the design. CFD thermal analyses on generic breeding unit including stiffening plates and cooling plates have been performed with ANSYS in order to consolidate results obtained with previous FEM design analyses. Moreover in order to expand the justification of the HCLL Breeding blanket design, the most loaded area of

  3. Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae) using amino acid nitrogen isotopic analyses

    Science.gov (United States)

    Choy, C. Anela; Davison, Peter C.; Drazen, Jeffrey C.; Flynn, Adrian; Gier, Elizabeth J.; Hoffman, Joel C.; McClain-Counts, Jennifer P.; Miller, Todd W.; Popp, Brian N.; Ross, Steve W.; Sutton, Tracey T.

    2012-01-01

    The δ15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ15N values. Regional differences in the δ15N values of phenylalanine confirmed that bulk tissue δ15N values reflect region-specific water mass biogeochemistry controlling δ15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP) for lanternfishes (family Myctophidae) (AA-TP ~2.9) largely align with expectations from stomach content studies (TP ~3.2), while AA-TPs for dragonfishes (family Stomiidae) (AA-TP ~3.2) were lower than TPs derived from stomach content studies (TP~4.1). We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.

  4. Tracing the diet of the monitor lizard Varanus mabitang by stable isotope analyses (δ15N, δ13C)

    Science.gov (United States)

    Struck, Ulrich; Altenbach, Alexander; Gaulke, Maren; Glaw, Frank

    2002-09-01

    In this study, we used analyses of stable isotopes of nitrogen (δ15N) and carbon (δ13C) to determine the trophic ecology of the monitor lizard Varanus mabitang. Stable isotopes from claws, gut contents, and soft tissues were measured from the type specimen. Samples from Varanus olivaceus, Varanus prasinus, Varanus salvator, the herbivorous agamid lizard Hydrosaurus pustulatus, and some plant matter were included for comparison. Our data show a rapid decrease in δ13C (about10‰) from food plants towards gut contents and soft tissues of herbivorous species. For the varanids, we found a significant linear correlation of decreasing δ13C and increasing δ15N from herbivorous towards carnivorous species. In terms of trophic isotope ecology, the type specimen of V. mabitang is a strict herbivore. Thus it differs significantly in its isotopic composition from the morphologically next closest related species V. olivaceus. The most highly carnivorous species is V. salvator, while δ15N values for V. prasinus and V. olivaceus are intermediate. Claws provide very valuable samples for such measurements, because they can be sampled from living animals without harm. Additionally, their range of variability is relatively small in comparison with measurements from soft tissues.

  5. Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae using amino acid nitrogen isotopic analyses.

    Directory of Open Access Journals (Sweden)

    C Anela Choy

    Full Text Available The δ(15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ(15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ(15N values. Regional differences in the δ(15N values of phenylalanine confirmed that bulk tissue δ(15N values reflect region-specific water mass biogeochemistry controlling δ(15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP for lanternfishes (family Myctophidae (AA-TP ∼2.9 largely align with expectations from stomach content studies (TP ∼3.2, while AA-TPs for dragonfishes (family Stomiidae (AA-TP ∼3.2 were lower than TPs derived from stomach content studies (TP∼4.1. We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.

  6. The lead (Pb) isotope signature, behaviour and fate of traffic-related lead pollution in roadside soils in The Netherlands.

    Science.gov (United States)

    Walraven, N; van Os, B J H; Klaver, G Th; Middelburg, J J; Davies, G R

    2014-02-15

    In this study the origin, behaviour and fate of anthropogenic Pb in sandy roadside soils were assessed by measuring soil characteristics, Pb isotope composition and content. In 1991 and 2003 samples were taken at different depth intervals at approximately 8 and 75 m from two highways in The Netherlands. The Pb isotope composition of the litter layer ((206)Pb/(207)Pb=1.12-1.14) differs from the deeper soil samples ((206)Pb/(207)Pb=1.20-1.21). Based on a mixing model it is concluded that the samples contain two Pb sources: natural Pb and anthropogenic Pb, the latter mainly derived from gasoline. (206)Pb/(207)Pb ratios demonstrate that the roadside soils were polluted to a depth of ~15 cm. Within this depth interval, anthropogenic Pb content is associated with organic matter. Although Pb pollution only reached a depth of ~15 cm, this does not mean that the topsoils retain all anthropogenic Pb. Due to the low pH and negligible binding capacity of soils at depths >15 cm, anthropogenic Pb migrated towards groundwater after reaching depths of >15 cm. The Pb isotope composition of the groundwater ((206)Pb/(207)Pb=1.135-1.185) establishes that groundwater is polluted with anthropogenic Pb. The contribution of anthropogenic Pb to the groundwater varies between ~30 and 100%. Based on the difference in soil Pb content and Pb isotope compositions over a period of 12 years, downward Pb migration is calculated to vary from 72 ± 95 to 324 ± 279 mg m(-2)y(-1). Assuming that the downward Pb flux is constant over time, it is calculated that 35-90% of the atmospherically delivered Pb has migrated to the groundwater.

  7. CORRESPONDENCE OF STABLE ISOTOPE AND GUT CONTENTS ANALYSES IN DETERMINING TROPHIC POSITION OF STREAM FISHES

    Science.gov (United States)

    It is generally accepted that both stable isotope analysis (SIA) and gut contents analysis (GCA) be used in food web studies; however, few researchers have analyzed these data in concert. We utilized SIA and GCA to determine if longitudinal and seasonal variation in diet affects...

  8. Comparing trophic position of stream fishes using stable isotope and gut contents analyses

    Science.gov (United States)

    Stable isotope analysis (SIA) and gut content analysis (GCA) are commonly used in food web studies, but few studies analyze these data in concert. We used SIA and GCA to identify diets and trophic position (TP) of six stream fishes and to compare TP estimates between methods. Ord...

  9. Multi-saline sample distillation apparatus for hydrogen isotope analyses : design and accuracy

    Science.gov (United States)

    Hassan, Afifa Afifi

    1981-01-01

    A distillation apparatus for saline water samples was designed and tested. Six samples may be distilled simultaneously. The temperature was maintained at 400 C to ensure complete dehydration of the precipitating salts. Consequently, the error in the measured ratio of stable hydrogen isotopes resulting from incomplete dehydration of hydrated salts during distillation was eliminated. (USGS)

  10. Electron–Rotor Interaction in Organic–Inorganic Lead Iodide Perovskites Discovered by Isotope Effects

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jue; Yang, Mengjin; Ma, Xiangchao; Schaller, Richard D.; Liu, Gang; Kong, Lingping; Yang, Ye; Beard, Matthew C.; Lesslie, Michael; Dai, Ying; Huang, Baibiao; Zhu, Kai; Xu, Tao

    2016-08-04

    We report on the carrier-rotor coupling effect in perovskite organic-inorganic hybrid lead iodide (CH3NH3PbI3) compounds discovered by isotope effects. Deuterated organic-inorganic perovskite compounds including CH3ND3PbI3, CD3NH3PbI3, and CD3ND3PbI3 were synthesized. Devices made from regular CH3NH3PbI3 and deuterated CH3ND3PbI3 exhibit comparable performance in band gap, current-voltage, carrier mobility, and power conversion efficiency. However, a time-resolved photoluminescence (TRPL) study reveals that CH3NH3PbI3 exhibits notably longer carrier lifetime than that of CH3ND3PbI3, in both thin-film and single-crystal formats. Furthermore, the comparison in carrier lifetime between CD3NH3PbI3 and CH3ND3PbI3 single crystals suggests that vibrational modes in methylammonium (MA+) have little impact on carrier lifetime. In contrast, the fully deuterated compound CD3ND3PbI3 reconfirmed the trend of decreasing carrier lifetime upon the increasing moment of inertia of cationic MA+. Polaron model elucidates the electron-rotor interaction.

  11. Fracture Mechanics Analyses of the Slip-Side Joggle Regions of Wing-Leading Edge Panels

    Science.gov (United States)

    Raju, Ivatury S.; Knight, Norman F., Jr.; Song, Kyongchan; Phillips, Dawn R.

    2010-01-01

    The Space Shuttle Orbiter wing comprises of 22 leading edge panels on each side of the wing. These panels are part of the thermal protection system that protects the Orbiter wings from extreme heating that take place on the reentry in to the earth atmosphere. On some panels that experience extreme heating, liberation of silicon carbon (SiC) coating was observed on the slip side regions of the panels. Global structural and local fracture mechanics analyses were performed on these panels as a part of the root cause investigation of this coating liberation anomaly. The wing-leading-edge reinforced carbon-carbon (RCC) panels, Panel 9, T-seal 10, and Panel 10, are shown in Figure 1 and the progression of the stress analysis models is presented in Figure 2. The global structural analyses showed minimal interaction between adjacent panels and the T-seal that bridges the gap between the panels. A bounding uniform temperature is applied to a representative panel and the resulting stress distribution is examined. For this loading condition, the interlaminar normal stresses showed negligible variation in the chord direction and increased values in the vicinity of the slip-side joggle shoulder. As such, a representative span wise slice on the panel can be taken and the cross section can be analyzed using plane strain analysis.

  12. 南京栖霞山铅锌矿区铅同位素示踪%Lead Isotopes as Tracers in the Qixiashang Lead-Zinc Mining Area,Nanjing

    Institute of Scientific and Technical Information of China (English)

    储彬彬; 罗立强; 王晓芳; 刘颖; 伯英

    2012-01-01

    南京栖霞山铅锌矿已开采50余年,环境问题日益突出.为了了解污染来源和污染传播方式,采集了该地水、土、植物、大气沉降、燃油灰尘、矿石、人血和生物等多种样品进行重金属元素含量和铅同位素示踪分析.结果表明矿区重金属污染严重,且污染随着靠近矿区而逐渐加重,重金属元素Pb、As、Cd、Cu、Zn之间相关性明显,初步反映了污染与矿山有关;同位素分析显示,矿区大气沉降样品、大部分植物样品、部分土壤和部分生物样品铅同位素组成与矿石铅同位素组成相似,证实了污染源为矿山.另外,大气沉降与植物样品铅含量高且它们的铅同位素组成相当,反映了大气沉降是污染传播方式之一.%The Qixiashan lead-zinc mine in Nanjing has been exploited for more than 50 years, and environmental pollution has become increasingly serious. In order to investigate the source and dispersion of the pollution, the authors collected water, soil, plants, atmospheric deposition, vehicle exhaust dust, ore, human blood and biological samples and analyzed heavy metals concentrations and lead isotopes with ICP-MS. The results show that the concentrations of heavy metals in soil, plants, and atmospheric deposition are very high, and the nearer to the mining area, the heavier the pollution. In addition, Pb, As, Cd, Cu and Zn show obvious correlation. Analyses of lead isotopes show that the lead isotope compositions in atmospheric deposition, plants, and part of soils and biological samples around the mining area are similar to those in ores, indicating that the pollution source has been derived form the mine. Furthermore, atmospheric deposition and plants have high lead concentrations and similar lead isotope compositions, suggesting that lead in atmospheric deposition contributes substantially to lead transfer.

  13. Computer analyses for the design, operation and safety of new isotope production reactors: A technology status review

    Energy Technology Data Exchange (ETDEWEB)

    Wulff, W.

    1990-01-01

    A review is presented on the currently available technologies for nuclear reactor analyses by computer. The important distinction is made between traditional computer calculation and advanced computer simulation. Simulation needs are defined to support the design, operation, maintenance and safety of isotope production reactors. Existing methods of computer analyses are categorized in accordance with the type of computer involved in their execution: micro, mini, mainframe and supercomputers. Both general and special-purpose computers are discussed. Major computer codes are described, with regard for their use in analyzing isotope production reactors. It has been determined in this review that conventional systems codes (TRAC, RELAP5, RETRAN, etc.) cannot meet four essential conditions for viable reactor simulation: simulation fidelity, on-line interactive operation with convenient graphics, high simulation speed, and at low cost. These conditions can be met by special-purpose computers (such as the AD100 of ADI), which are specifically designed for high-speed simulation of complex systems. The greatest shortcoming of existing systems codes (TRAC, RELAP5) is their mismatch between very high computational efforts and low simulation fidelity. The drift flux formulation (HIPA) is the viable alternative to the complicated two-fluid model. No existing computer code has the capability of accommodating all important processes in the core geometry of isotope production reactors. Experiments are needed (heat transfer measurements) to provide necessary correlations. It is important for the nuclear community, both in government, industry and universities, to begin to take advantage of modern simulation technologies and equipment. 41 refs.

  14. Analytical pyrolysis and stable isotope analyses reveal past environmental changes in coralloid speleothems from Easter Island (Chile).

    Science.gov (United States)

    Miller, Ana Z; De la Rosa, José M; Jiménez-Morillo, Nicasio T; Pereira, Manuel F C; González-Pérez, José A; Calaforra, José M; Saiz-Jimenez, Cesareo

    2016-08-26

    This study comprises an innovative approach based on the combination of chromatography (analytical pyrolysis and pyrolysis compound-specific isotope analysis (Py-CSIA)), light stable isotopes, microscopy and mineralogy analyses to characterize the internal layering of coralloid speleothems from the Ana Heva lava tube in Easter Island (Chile). This multidisciplinary proxy showed that the speleothems consist of banded siliceous materials of low crystallinity with different mineralogical compositions and a significant contribution of organic carbon. Opal-A constitutes the outermost grey layer of the coralloids, whereas calcite and amorphous Mg hydrate silicate are the major components of the inner whitish and honey-brown layers, respectively. The differences found in the mineralogical, elemental, molecular and isotopic composition of these distinct coloured layers are related to environmental changes during speleothem development. Stable isotopes and analytical pyrolysis suggested alterations in the water regime, pointing to wetter conditions during the formation of the Ca-rich layer and a possible increase in the amount of water dripping into the cave. The trend observed for δ(15)N values suggested an increase in the average temperature over time, which is consistent with the so-called climate warming during the Holocene. The pyrolysis compound-specific isotope analysis of each speleothem layer showed a similar trend with the bulk δ(13)C values pointing to the appropriateness of direct Py-CSIA in paleoenvironmental studies. The δ(13)C values for n-alkanes reinforced the occurrence of a drastic environmental change, indicating that the outermost Opal layer was developed under drier and more arid environmental conditions.

  15. Lead isotope ratios in tree bark pockets: An indicator of past air pollution in the Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Conkova, M. [Charles University, Faculty of Natural Sciences, Benatska 8, Prague 1 (Czech Republic)], E-mail: conkova@chmi.cz; Kubiznakova, J. [Czech Hydrometeorogical Institute, Na Sabatce 17, Prague 4 (Czech Republic)], E-mail: kubiznakova@chmi.cz

    2008-10-15

    Tree bark pockets were collected at four sites in the Czech Republic with differing levels of lead (Pb) pollution. The samples, spanning 1923-2005, were separated from beech (Fagus sylvatica) and spruce (Picea abies). Elevated Pb content (0.1-42.4 {mu}g g{sup -1}) reflected air pollution in the city of Prague. The lowest Pb content (0.3-2.6 {mu}g g{sup -1}) was found at the Kosetice EMEP 'background pollution' site. Changes in {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 206}Pb isotope ratios were in agreement with operation times of the Czech main anthropogenic Pb sources. Shortly after the Second World War, the {sup 206}Pb/{sup 207}Pb isotope ratio in bark pockets decreased from 1.17 to 1.14 and the {sup 208}Pb/{sup 206}Pb isotope ratio increased from 2.12 to 2.16. Two dominant emission sources responsible for these changes, lignite and leaded petrol combustion, contributed to the shifts in Pb isotope ratios. Low-radiogenic petrol Pb ({sup 206}Pb/{sup 207}Pb of 1.11) lead to lower {sup 206}Pb/{sup 207}Pb in bark pockets over time. High-radiogenic lignite-derived Pb ({sup 206}Pb/{sup 207}Pb of 1.18 to 1.19) was detected in areas affected by coal combustion rather than by traffic.

  16. Propagation of Isotopic Bias and Uncertainty to Criticality Safety Analyses of PWR Waste Packages

    Energy Technology Data Exchange (ETDEWEB)

    Radulescu, Georgeta [ORNL

    2010-06-01

    Burnup credit methodology is economically advantageous because significantly higher loading capacity may be achieved for spent nuclear fuel (SNF) casks based on this methodology as compared to the loading capacity based on a fresh fuel assumption. However, the criticality safety analysis for establishing the loading curve based on burnup credit becomes increasingly complex as more parameters accounting for spent fuel isotopic compositions are introduced to the safety analysis. The safety analysis requires validation of both depletion and criticality calculation methods. Validation of a neutronic-depletion code consists of quantifying the bias and the uncertainty associated with the bias in predicted SNF compositions caused by cross-section data uncertainty and by approximations in the calculational method. The validation is based on comparison between radiochemical assay (RCA) data and calculated isotopic concentrations for fuel samples representative of SNF inventory. The criticality analysis methodology for commercial SNF disposal allows burnup credit for 14 actinides and 15 fission product isotopes in SNF compositions. The neutronic-depletion method for disposal criticality analysis employing burnup credit is the two-dimensional (2-D) depletion sequence TRITON (Transport Rigor Implemented with Time-dependent Operation for Neutronic depletion)/NEWT (New ESC-based Weighting Transport code) and the 44GROUPNDF5 crosssection library in the Standardized Computer Analysis for Licensing Evaluation (SCALE 5.1) code system. The SCALE 44GROUPNDF5 cross section library is based on the Evaluated Nuclear Data File/B Version V (ENDF/B-V) library. The criticality calculation code for disposal criticality analysis employing burnup credit is General Monte Carlo N-Particle (MCNP) Transport Code. The purpose of this calculation report is to determine the bias on the calculated effective neutron multiplication factor, k{sub eff}, due to the bias and bias uncertainty associated with

  17. Lead isotopes in iron and manganese oxide coatings and their use as an exploration guide for concealed mineralization

    Science.gov (United States)

    Gulson, B.L.; Church, S.E.; Mizon, K.J.; Meier, A.L.

    1992-01-01

    Lead isotopes from Fe and Mn oxides that coat stream pebbles from around the Mount Emmons porphyry molybdenum deposit in Colorado were studied to assess the feasibility of using Pb isotopes to detect concealed mineral deposits. The Fe/Mn oxide coatings were analyzed to determine their elemental concentrations using ICP-AES. The Pb isotope compositions of solutions from a selected suite of samples were measured, using both thermal ionization and ICP mass spectrometry, to compare results determined by the two analytical methods. Heavy mineral concentrates from the same sites were also analyzed to compare the Pb isotope compositions of the Fe/Mn coatings with those found in panned concentrates. The Fe/Mn and 206Pb/204Pb ratios of the oxide coatings are related to the lithology of the host rocks; Fe/Mn oxide coatings on pebbles of black shale have higher Fe/Mn values than do the coatings on either sandstone or igneous rocks. The shale host rocks have a more radiogenic signature (e.g. higher 206Pb/ 204Pb) than the sandstone or igneous host rocks. The Pb isotope data from sandstone and igneous hosts can detect concealed mineralized rock on both a regional and local scale, even though there are contributions from: (1) metals from the main-stage molybdenite ore deposit; (2) metals from the phyllic alteration zone which has a more radiogenic Pb isotope signature reflecting hydrothermal leaching of Pb from the Mancos Shale; (3) Pb-rich base metal veins with a highly variable Pb isotope signature; and (4) sedimentary country rocks which have a more radiogenic Pb isotope signature. An investigation of within-stream variation shows that the Pb isotope signature of the molybdenite ore zone is retained in the Fe/Mn oxide coatings and is not camouflaged by contributions from Pb-rich base-metal veins that crop out upstream. In another traverse, the Pb isotope data from Fe/Mn oxide coatings reflect a complex mixing of Pb from the molybdenite ore zone and its hornfels margin, Pb

  18. Combined U-Pb and Lu-Hf isotope analyses by laser ablation MC-ICP-MS: methodology and applications

    Energy Technology Data Exchange (ETDEWEB)

    Matteini, Massimo; Dantas, Elton L.; Pimentel, Marcio M.; Bühn, Bernhard, E-mail: massimo@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Instituto de Geociencias

    2010-06-15

    The Lutetium-Hafnium isotopic system represents one of the most innovative and powerful tools for geochronology and isotopic studies. Combined U-Pb and Lu-Hf in situ analyses on zircon by LA-MC-ICP-MS permit to characterize isotopically the host magma from which it crystallized furnishing significant information for sediment provenance and crustal evolution studies. In this paper e describe the Lu-Hf systematic by LA-MC-ICP-MS developed in the laboratory of Geochronology of the University of Brasilia and report the results obtained by repeated analyses of {sup 176}Hf/{sup 177}Hf isotopic ratio of three zircon standards: GJ-1 = 0.282022 ± 11 (n=56), Temora 2 = 0.282693 ± 14 (n=25) and UQZ = 0.282127 ± 33 (n=11). The {sup 176}Hf/{sup 177}Hf ratio (0.282352 ± 22, n=14) of gem quality zircon used as in-house standard have been also characterized. As a geological application, we analyzed two complex zircons selected from a migmatitic rocks from the Borborema Province, NE Brazil. On the basis of U-Pb and Lu-Hf data, two main crystallization events have been identified in both studied zircons. An older event at ca. 2.05 Ga recognized in the inherited cores represents a well-characterized paleoproterozoic magmatic event that affected the whole Borborema Province. A second crystallization event at ∼ 575 Ma, recognized at the rims, represents a Neoproterozoic (Brazilian) high grade metamorphic-magmatic event. (author)

  19. Ultratrace and isotope ratios analyses of some radionuclides by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Helal, A.I.; Zahran, N.F.; Abd El-Lateef, A.M.; Mohsen, H.T. [Central Lab. for Elemental and Isotopic Analysis, N.R.C. Atomic Energy Authority, Cairo (Egypt); Amr, M.A. [Central Lab. for Elemental and Isotopic Analysis, N.R.C. Atomic Energy Authority, Cairo (Egypt); Nuclear Physics Dept., N.R.C., Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Dept., Faculty of Science, Zagazig Univ. (Egypt); Abbas, Y. [Physics Dept., Faculty of Science, Suez Canal Univ., Ismailia (Egypt)

    2004-07-01

    Extensive work is under way using high resolution-ICP-MS for {sup 90}Sr, {sup 234}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Am detection. Sample preparation procedures based on liquid-liquid extraction and ion exchange chromatography were developed. Sr, U, Pu, and Am were separated from their matrix and concentrated to improve the power of detection in the mass spectrometer. A microconcentric nebulizer with a desolvation introduction system (Ardius) is used. Instrumental limits of detection using Sr and U standard solutions are 0.01 ppt and 0.006 ppt for Sr and U, respectively. A study is presented on the mass interferences for the specified radionuclides. In the environmental samples investigated the {sup 90}Sr/{sup 86}Sr isotope ratio is 6.02 x 10{sup -9} and for {sup 240}Pu/{sup 239}Pu the isotope ratio is 0.17. (orig.)

  20. Validation of the scale system for PWR spent fuel isotopic composition analyses

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, O.W.; Bowman, S.M.; Parks, C.V. [Oak Ridge National Lab., TN (United States); Brady, M.C. [Sandia National Laboratories, Las Vegas, NV (United States)

    1995-03-01

    The validity of the computation of pressurized-water-reactor (PWR) spent fuel isotopic composition by the SCALE system depletion analysis was assessed using data presented in the report. Radiochemical measurements and SCALE/SAS2H computations of depleted fuel isotopics were compared with 19 benchmark-problem samples from Calvert Cliffs Unit 1, H. B. Robinson Unit 2, and Obrigheim PWRs. Even though not exhaustive in scope, the validation included comparison of predicted and measured concentrations for 14 actinides and 37 fission and activation products. The basic method by which the SAS2H control module applies the neutron transport treatment and point-depletion methods of SCALE functional modules (XSDRNPM-S, NITAWL-II, BONAMI, and ORIGEN-S) is described in the report. Also, the reactor fuel design data, the operating histories, and the isotopic measurements for all cases are included in detail. The underlying radiochemical assays were conducted by the Materials Characterization. Center at Pacific Northwest Laboratory as part of the Approved Testing Material program and by four different laboratories in Europe on samples processed at the Karlsruhe Reprocessing Plant.

  1. Comparative assessment of air quality in two health resorts using carbon isotopes and palynological analyses

    Energy Technology Data Exchange (ETDEWEB)

    Gorka, M.; Jedrysek, M.O.; Maj, J.; Worobiec, A.; Buczynska, A.; Stefaniak, E.; Krata, A.; Van Grieken, R.; Zwozdziak, A.; Sowka, I.; Zwozdziak, J.; Lewicka-Szczebak, D. [University of Wroclaw, Wroclaw (Poland). Inst. of Geological Science

    2009-01-15

    This paper describes results of applying the palynological and carbon isotopic analysis of the organic fraction of Total Suspended Particles (TSP) to discriminate distinct pollution sources and assess the anthropogenic impact for the investigated areas. The samples of atmospheric particles were collected in Czerniawa and Cieplice (two health resorts in Lower Silesia, SW Poland) twice a year in summer and winter season (from July 2006 to February 2008). The palynological spectra represent in the vast majority local plant communities without a noticeable contribution of long-transported plant particles. Palynological analysis revealed also differences in the specificity of the two sampling areas, i.e. the higher contribution of identified organic material in Czerniawa stands for more natural character of this site, but is also responsible for the higher allergic pressure when compared to Cieplice. The carbon isotopic composition of TSP varied seasonally ({delta}{sup 13}C value from -27.09 parts per thousand in summer to -25.47 parts per thousand in winter). The increased {delta} {sup 13}C value in winter (heating period) is most probably caused by uncontrolled contribution of coal soot. On the basis of isotopic mass balance the calculated contribution of anthropogenic organic particles in the atmosphere reached in winter season 72% in Czerniawa and 79% in Cieplice.

  2. Isotope analyses to explore diet and mobility in a medieval Muslim population at Tauste (NE Spain).

    Science.gov (United States)

    Guede, Iranzu; Ortega, Luis Angel; Zuluaga, Maria Cruz; Alonso-Olazabal, Ainhoa; Murelaga, Xabier; Pina, Miriam; Gutierrez, Francisco Javier; Iacumin, Paola

    2017-01-01

    The Islamic necropolis discovered in Tauste (Zaragoza, Spain) is the only evidence that a large Muslim community lived in the area between the 8th and 10th centuries. A multi-isotope approach has been used to investigate the mobility and diet of this medieval Muslim population living in a shifting frontier region. Thirty-one individuals were analyzed to determine δ15N, δ13C, δ18O and 87Sr/86Sr composition. A combination of strontium and oxygen isotope analysis indicated that most individuals were of local origin although three females and two males were non-local. The non-local males would be from a warmer zone whereas two of the females would be from a more mountainous geographical region and the third from a geologically-different area. The extremely high δ15N baseline at Tauste was due to bedrock composition (gypsum and salt). High individual δ15N values were related to the manuring effect and consumption of fish. Adult males were the most privileged members of society in the medieval Muslim world and, as isotope data reflected, consumed more animal proteins than females and young males.

  3. Trophic structure of a coastal fish community determined with diet and stable isotope analyses.

    Science.gov (United States)

    Malek, A J; Collie, J S; Taylor, D L

    2016-09-01

    A combination of dietary guild analysis and nitrogen (δ(15) N) and carbon (δ(13) C) stable-isotope analysis was used to assess the trophic structure of the fish community in Rhode Island and Block Island Sounds, an area off southern New England identified for offshore wind energy development. In the autumn of 2009, 2010 and 2011, stomach and tissue samples were taken from 20 fish and invertebrate species for analysis of diet composition and δ(15) N and δ(13) C signatures. The food chain in Rhode Island and Block Island Sounds comprises approximately four trophic levels within which the fish community is divided into distinct dietary guilds, including planktivores, benthivores, crustacivores and piscivores. Within these guilds, inter-species isotopic and dietary overlap is high, suggesting that resource partitioning or competitive interactions play a major role in structuring the fish community. Carbon isotopes indicate that most fishes are supported by pelagic phytoplankton, although there is evidence that benthic production also plays a role, particularly for obligate benthivores such as skates Leucoraja spp. This type of analysis is useful for developing an ecosystem-based approach to management, as it identifies species that act as direct links to basal resources as well as species groups that share trophic roles.

  4. Lead and its isotopes in the sediment of three sites on the Lebanese coast: Identification of contamination sources and mobility

    Energy Technology Data Exchange (ETDEWEB)

    Abi-Ghanem, C., E-mail: carine.a.ghanem@hotmail.fr [Centre National des Sciences Marines, CNRSL, P.O. Box 534, Batroun (Lebanon); Chiffoleau, J.F. [Ifremer, LBCM, Centre de Nantes, BP 21105, F.44311 Nantes cedex 3 (France); Bermond, A. [Agro-ParisTech, 16, rue C. Bernard, F.75231 Paris cedex 5 (France); Nakhle, K.; Khalaf, G. [Centre National des Sciences Marines, CNRSL, P.O. Box 534, Batroun (Lebanon); Borschneck, D. [CEREGE CNRS, Aix-Marseille University, Europole Mediterraneen de l' Arbois, BP 80, 13545 Aix-en-Provence (France); Cossa, D. [Ifremer, LBCM, Centre de Nantes, BP 21105, F.44311 Nantes cedex 3 (France)

    2009-10-15

    Lead concentrations and isotopic composition of sediment samples collected from three sites within the Lebanese coastal zones were measured: at Akkar, Dora and Selaata. Akkar is located far from any direct source of contamination, while Dora and Selaata receive urban and industrial wastes, respectively. Low Pb concentrations (6-16 {mu}g g{sup -1}) were detected in the Akkar sediments, and high concentrations of Pb (70-101 {mu}g g{sup -1}) were detected in the Dora sediments. Measuring stable isotope ratios of Pb makes it possible to identify the principal sources of Pb in the Akkar sediments as Pb emitted from gasoline combustion and Pb originating from natural sources. On the other hand, Pb stable isotopic ratios in Dora sediments indicate that they are more highly influenced by anthropogenic sources. Isotopic Pb ratios in the Selaata deposits, where Pb concentrations range between 5 and 35 {mu}g g{sup -1}, have an exceptional radiogenic signature for marine sediments 1.25 < {sup 206}Pb/{sup 207}Pb < 1.6 and 0.5 < {sup 206}Pb/{sup 208}Pb < 0.67, which shows the impact of the phosphogypsum discharged by Selaata's chemical plant. Isotopic Pb analysis applied to EDTA extracts, to test the mobility of Pb, shows that that this mobility is high (>60%) after 24 h of extraction, and that the extracted Pb is less radiogenic than the residual Pb.

  5. Contrasting origins of the upper mantle revealed by hafnium and lead isotopes from the Southeast Indian Ridge.

    Science.gov (United States)

    Hanan, Barry B; Blichert-Toft, Janne; Pyle, Douglas G; Christie, David M

    2004-11-04

    The origin of the isotopic signature of Indian mid-ocean ridge basalts has remained enigmatic, because the geochemical composition of these basalts is consistent either with pollution from recycled, ancient altered oceanic crust and sediments, or with ancient continental crust or lithosphere. The radiogenic isotopic signature may therefore be the result of contamination of the upper mantle by plumes containing recycled altered ancient oceanic crust and sediments, detachment and dispersal of continental material into the shallow mantle during rifting and breakup of Gondwana, or contamination of the upper mantle by ancient subduction processes. The identification of a process operating on a scale large enough to affect major portions of the Indian mid-ocean ridge basalt source region has been a long-standing problem. Here we present hafnium and lead isotope data from across the Indian-Pacific mantle boundary at the Australian-Antarctic discordance region of the Southeast Indian Ridge, which demonstrate that the Pacific and Indian upper mantle basalt source domains were each affected by different mechanisms. We infer that the Indian upper-mantle isotope signature in this region is affected mainly by lower continental crust entrained during Gondwana rifting, whereas the isotope signature of the Pacific upper mantle is influenced predominantly by ocean floor subduction-related processes.

  6. Parametric analyses of summative scores may lead to conflicting inferences when comparing groups: A simulation study.

    Science.gov (United States)

    Khan, Asaduzzaman; Chien, Chi-Wen; Bagraith, Karl S

    2015-04-01

    To investigate whether using a parametric statistic in comparing groups leads to different conclusions when using summative scores from rating scales compared with using their corresponding Rasch-based measures. A Monte Carlo simulation study was designed to examine between-group differences in the change scores derived from summative scores from rating scales, and those derived from their corresponding Rasch-based measures, using 1-way analysis of variance. The degree of inconsistency between the 2 scoring approaches (i.e. summative and Rasch-based) was examined, using varying sample sizes, scale difficulties and person ability conditions. This simulation study revealed scaling artefacts that could arise from using summative scores rather than Rasch-based measures for determining the changes between groups. The group differences in the change scores were statistically significant for summative scores under all test conditions and sample size scenarios. However, none of the group differences in the change scores were significant when using the corresponding Rasch-based measures. This study raises questions about the validity of the inference on group differences of summative score changes in parametric analyses. Moreover, it provides a rationale for the use of Rasch-based measures, which can allow valid parametric analyses of rating scale data.

  7. Winter diets of immature green turtles (Chelonia mydas) on a northern feeding ground: integrating stomach contents and stable isotope analyses

    Science.gov (United States)

    Williams, Natalie C.; Bjorndal, Karen A.; Lamont, Margaret M.; Carthy, Raymond R.

    2015-01-01

    The foraging ecology and diet of the green turtle, Chelonia mydas, remain understudied, particularly in peripheral areas of its distribution. We assessed the diet of an aggregation of juvenile green turtles at the northern edge of its range during winter months using two approaches. Stomach content analyses provide a single time sample, and stable isotope analyses integrate diet over a several-month period. We evaluated diet consistency in prey choice over time by comparing the results of these two approaches. We examined stomach contents from 43 juvenile green turtles that died during cold stunning events in St. Joseph Bay, Florida, in 2008 and 2011. Stomach contents were evaluated for volume, dry mass, percent frequency of occurrence, and index of relative importance of individual diet items. Juvenile green turtles were omnivorous, feeding primarily on seagrasses and tunicates. Diet characterizations from stomach contents differed from those based on stable isotope analyses, indicating the turtles are not feeding consistently during winter months. Evaluation of diets during warm months is needed.

  8. Preliminary study of microscale zircon oxygen isotopes for Dabie-Sulu metamorphic rocks: Ion probe in situ analyses

    Institute of Scientific and Technical Information of China (English)

    CHEN Daogong; Deloule Etienne; CHENG Hao; XIA Qunke; WU Yuanbao

    2003-01-01

    151 in situ analyses of oxygen isotopes were carried out by ion micro-probe for zircons from 8 localities of HP-UHP metamorphic rocks including eclogites in the Dabie-Sulu terrane. The results show significant heterogeneity inδ18O values, with variation in different rocks from -8.5‰ to +9.7‰ and within one sample from 2‰ to 12‰. No measurable difference inδ18O was observed between protolith magmatic (detrital) zircons and metamorphic recrystallized zircons within analytical uncertainties from the ion micro-probe measurements. This indicates that the metamorphic zircons have inherited the oxygen isotopic compositions of protolith zircons despite the HP to UHP metamorphism. According to their protolith ages from zircon U-Pb in situ dating by the same ion micro-probe, two groups of oxygen isotope composition are recognized, with one having δ18O values of 6‰-7‰ for old protolith of 1.9-2.5 Ga ages and the other 0‰-2‰ for young protolith of 0.7-0.8 Ga ages. The latter anomalously lowδ18O values of zircons indicate that the magma has had the obvious involvement of meteoric water when forming the young protolith of high-grade metamorphic rocks. This may be correlated with the snowball Earth event occurring in South China and the world elsewhere during the Neoproterozoic.

  9. Isotopic analyses of food crusts on pottery: Implications for dating and palaeocuisine reconstructions

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2015-01-01

    The concentrations of the stable carbon and nitrogen isotopes, δ13C and δ15N, can be used to roughly reconstruct the former content of Stone Age cooking vessels. This was supported by measurements on experimental food crusts. The reconstruction of the ingredients used in the vessels is not only...... relevant for reconstructing the diet, but also important for 14C-dating. Resources from sea- or freshwater can cause substantial radiocarbon reservoir effects. For a reliable 14C-dating, they therefore have to be identified. This study presents 14C-datings of the earliest pottery of Schleswig...

  10. Diplodon shells from Northwest Patagonia as continental proxy archives: Oxygen isotopic results and sclerochronological analyses

    Science.gov (United States)

    Soldati, A. L.; Beierlein, L.; Jacob, D. E.

    2009-04-01

    Freshwater mussels of the genus Diplodon (Bivalvia, Hyriidae) are the most abundant bivalve (today and in the past) in freshwater bodies at both sides of the South-Andean Cordillera. There are about 25 different Diplodon genera in Argentina and Chile that could be assigned almost completely to the species Diplodon chilensis (Gray, 1828) and two subspecies: D. ch. chilensis and D. ch. patagonicus; this latter species is found in Argentina between Mendoza (32˚ 52' S; 68˚ 51' W) and Chubut (45˚ 51' S; 67˚ 28' W), including the lakes and rivers of the target area, the Nahuel Huapi National Park (Castellanos, 1960). Despite their wide geographic distribution, Diplodon species have only rarely been used as climate archives in the southern hemisphere. Kaandorp et al. (2005) demonstrated for Diplodon longulus (Conrad 1874) collected from the Peruvian Amazonas that oxygen isotopic patterns in the shells could be used in order to reconstruct the precipitation regime and dry/wet seasonal of the monsoonal system in Amazonia. Although this study demonstrated the potential of Diplodon in climatological and ecological reconstructions in the southern hemisphere, as of yet, no systematic study of Diplodon as a multi-proxy archive has been undertaken for the Patagonian region. In this work we present sclerochronological analyses supported by ^18Oshell in recent mussel of Diplodon chilensis patagonicus (D'Orbigny, 1835) collected at Laguna El Trébol (42°S-71°W, Patagonia Argentina), one of the best studied water bodies in the region for paleoclimate analysis. Water temperature was measured every six hours for one year using a temperature sensor (Starmon mini®) placed at 5m depth in the lake, close to a mussel bank. Additionally, ^18Owater was measured monthly for the same time range.g^18Oshell values obtained by micro-milling at high spatial resolution in the growth increments of three Diplodon shells were compared to these records, and to air temperature and

  11. The effects of succimer on the absorption of lead in adults determined by using the stable isotope [sup 204]Pb

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.R. (Univ. of California, San Francisco, CA (United States) Univ. of California, Santa Cruz, CA (United States)); Markowitz, M.E.; Rosen, J.F. (Albert Einstein College of Medicine, Bronx, NY (United States)); Crick, J.; Flegal, A.R. (Univ. of California, Santa Cruz, CA (United States))

    1994-10-01

    The chelating agent succimer (meso-2,3-dimercaptosuccine acid) is orally effective at inducing a urinary lead diuresis and a decrease in blood lead levels in lead poisoned children and adults. However, there are concerns that succimer may increase the absorption of lead from the gastrointestinal (GI) tract during treatment, particularly in cases of continuing lead exposure, which would compromise its effectiveness in reducing whole body lead stores. This preliminary study investigated the effects of succimer on the absorption of lead in adults using a stable lead isotopic tracer ([sup 204]Pb). Twelve male subjects were divided into control (no succimer), 10, and 30 mg succimer/kg body wt treatment groups of 4 individuals each. All subjects ingested a single tracer dose (200 [mu]g) of [sup 204]Pb, followed by a single oral dose of placebo (control) or succimer. Whole blood was collected at intervals of 0, 2, 4, and [approx] 26 hr following ingestion of the [sup 204]Pb tracer, and composite urine and feces samples were collected over the duration of the study ([approx] 26 hr). Mean intestinal excretion of [sup 204]Pb was reduced in the succimer-treated groups compared to the control (placebo), whereas urinary diuresis of [sup 204]Pb was higher in the succimer groups. The amount of lead [sup 204]Pb tracer accounted for at the end of the study was lower in the succimer-treated groups. These results suggest that GI lead absorption was enhanced by succimer and that succimer mediated the redistribution of lead from the circulation to other tissues. However, none of the differences between treatment groups were statistically significant (P < 0.05, t test) because of the relatively large within-group variability. This study demonstrates the utility of microgram doses of a stable lead isotopic tracer to assess the efficacy of clinical chelating agents in humans. 39 refs., 1 fig., 2 tabs.

  12. A "Tail" Of Two Mines: Determining The Sources Of Lead In Mine Waters Using Pb Isotopes

    Science.gov (United States)

    Cousens, B. L.; Allen, D. M.; Lepitre, M. E.; Mortensen, J. K.; Gabites, J. E.; Nugent, M.; Fortin, D.

    2004-12-01

    Acid mine drainage can be a significant environmental problem in regions where mine tailings are exposed to surface water and shallow groundwater flow. Whereas high metal concentrations in surface waters and groundwaters indicate that metals are being mobilized, these data do not uniquely identify the source of the contamination. The isotopic composition of Pb in mine waters is a superb tracer of Pb sources, because the isotopic composition of ore Pb is usually significantly different from that of host rocks, other surficial deposits, and aerosols. We have investigated metal mobility at two abandoned Pb-Zn mines in different geological settings: the sediment-hosted Sullivan Mine in southeastern British Columbia, and the New Calumet Mine of western Quebec that is hosted in metamorphic rocks of the Grenville Province. Ores from both mines have homogeneous Pb isotopic compositions that are much less radiogenic than surrounding host rocks. At Sullivan, the Pb isotopic compositions of water samples define a mixing line between Sullivan ore and at least one other more radiogenic end-member. Water samples with high Pb concentrations (0.002 to 0.3 mg/L) generally are acidic and have Pb isotope ratios equal to Sullivan ore, whereas waters with low Pb contents have near-neutral pH and have variably more radiogenic Pb isotope ratios. Thus not all the waters collected in the study area originate from Sullivan ore or mining operations, as previously thought. The dominant source of ore Pb in mine waters are the waste rock dumps. Based on their isotopic compositions, host shales or aerosols from the local Pb smelter are potential sources of non-Sullivan ore Pb; local glacial tills are an unlikely source due to their heterogeneous Pb isotopic composition. Similarly, at the New Calumet mine, water samples collected in direct contact with either ore at the surface or tailings have high Pb concentrations (up to 0.02 mg/L) and Pb isotope ratios equal to New Calumet Pb-Zn ore. However

  13. Lead Isotopes in Olivine-Phyric Shergottite Tissint: Implications for the Geochemical Evolution of the Shergottite Source Mantle

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Simon, J. I.; Jones, J. H.; Yokoyama, T.

    2015-01-01

    Geochemically-depleted shergottites are basaltic rocks derived from a martian mantle source reservoir. Geochemical evolution of the martian mantle has been investigated mainly based on the Rb-Sr, Sm-Nd, and Lu-Hf isotope systematics of the shergottites [1]. Although potentially informative, U-Th- Pb isotope systematics have been limited because of difficulties in interpreting the analyses of depleted meteorite samples that are more susceptible to the effects of near-surface processes and terrestrial contamination. This study conducts a 5-step sequential acid leaching experiment of the first witnessed fall of the geochemically-depleted olivinephyric shergottite Tissint to minimize the effect of low temperature distrubence. Trace element analyses of the Tissint acid residue (mostly pyroxene) indicate that Pb isotope compositions of the residue do not contain either a martian surface or terrestrial component, but represent the Tissint magma source [2]. The residue has relatively unradiogenic initial Pb isotopic compositions (e.g., 206Pb/204Pb = 10.8136) that fall within the Pb isotope space of other geochemically-depleted shergottites. An initial µ-value (238U/204Pb = 1.5) of Tissint at the time of crystallization (472 Ma [3]) is similar to a time-integrated mu- value (1.72 at 472 Ma) of the Tissint source mantle calculated based on the two-stage mantle evolution model [1]. On the other hand, the other geochemically-depleted shergottites (e.g., QUE 94201 [4]) have initial µ-values of their parental magmas distinctly lower than those of their modeled source mantle. These results suggest that only Tissint potentially reflects the geochemical signature of the shergottite mantle source that originated from cumulates of the martian magma ocean

  14. Run-off analyses using isotopes and hydrochemistry in Yushugou River basin, eastern Tianshan Mountains

    Indian Academy of Sciences (India)

    Xiaoyan Wang; Zhongqin Li; Chanwen Jiang

    2017-08-01

    Yushugou River basin of East Tianshan Mountains receives water from melting glaciers. In recent years, the glaciers retreated strongly due to global warming which intensified the water cycle in the river basin. For this reason, the relation of water bodies based on hydrochemistry and isotope in the summer flood was carried out. Hydrochemistry research showed that there was frequent hydraulic interaction between river water and groundwater. Studying the isotopes and Cl− of river water, glacier meltwater, groundwater and precipitation, indicated that Yushugou River was recharged by the glacier meltwater, groundwater and precipitation during the summer flood period. The analysis result based on the three-component mixing model showed that Yushugou River was recharged by 54.9% of glacier meltwater, 37.6% of the run-off came from groundwater, while less than 8% was contributed by precipitation. The study suggests that the role of glacier meltwater and groundwater, especially glacier meltwater, should be specially concerned in water resource protection and reasonable utilization, and the injection of glacier meltwater is the main reason for run-off variation in this alpine basin during the summer flood period.

  15. Comparison of neutron cross sections for selected fission products and isotopic composition analyses with burnup

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Gil, C. S.; Kim, J. D.; Jang, J. H.; Lee, Y. D. [KAERI, Taejon (Korea)

    2003-10-01

    The neutron absorption cross sections for 18 fission products evaluated within the framework of the KAERI-BNL international collaboration have been compared with the ENDF/B-VI release 7. Also, the influence of the new evaluations on isotopic compositions of the fission products as a function of burnup has been analyzed through the OECD/NEA burnup credit criticality benchmarks (Phase 1B) and the LWR/Pu recycling benchmarks. These calculations were performed by WIMSD-5B with the 69 group libraries prepared from three evaluated nuclear data libraries: ENDF/B-VI.7, ENDF/B-VI.8 including new evaluations in resonance region covering thermal region, and ENDF/B-VII expected including those in upper resonance region up to 20 MeV. For Xe-131, the composition calculated with ENDF/B-VI.8 shows maximum difference of 4.78% compared to ENDF/B-VI.7. However, the isotopic compositions of all fission products calculated with ENDF/B-VII shows no differences compared to ENDF/B-VI.7.

  16. Lead isotopes tracing the life cycle of a catchment: From source rock via weathering to human impact

    Science.gov (United States)

    Negrel, P. J.; Petelet-Giraud, E.; Guerrot, C.; Millot, R.

    2015-12-01

    Chemical weathering of rocks involves consumption of CO2, a greenhouse gas with a strong influence on climate. Among rocks exposed to weathering, basalt plays a major role in the carbon cycle as it is more easily weathered than other crystalline silicate rocks. This means that basalt weathering acts as a major atmospheric CO2 sink. The present study investigated the lead isotopes in rock, soil and sediment for constraining the life cycle of a catchment, covering source rocks, erosion processes and products, and anthropogenic activities. For this, we investigated the Allanche river drainage basin in the Massif Central, the largest volcanic areas in France, that offers opportunities for selected geochemical studies since it drains a single type of virtually unpolluted volcanic rock, with agricultural activity increasing downstream. Soil and sediment are derived exclusively from basalt weathering, and their chemistry, coupled to isotope tracing, should shed light on the behavior of chemical species during weathering from parental bedrock. Bedrock samples of the basin, compared to regional bedrock of the volcanic province, resulted from a complex history and multiple mantle reservoir sources and mixing. Regarding soils and sediments, comparison of Pb and Zr normalized to mobile K shows a linear evolution of weathering processes, whereby lead enrichment from atmospheric deposition is the other major contributor. Lead-isotope ratios showed that most of the lead budget in sediment and soil results from bedrock weathering with an influence of past mining and mineral processing of ores in the Massif Central, and deposition of lead-rich particles from gasoline combustion, but no lead input from agricultural activity. A classic box model was used to investigate the dynamics of sediment transfer at the catchment scale, the lead behavior in the continuum bedrock-soil-sediment and the historical evolution of anthropogenic aerosol emissions.

  17. A stable lead isotopic investigation of the use of sycamore tree rings as a historical biomonitor of environmental lead contamination.

    Science.gov (United States)

    Patrick, Gavin J; Farmer, John G

    2006-06-01

    The validity of the use of sycamore (Acer pseudoplatanus) tree-rings for the reconstruction of atmospheric lead pollution histories was investigated. Tree cores spanning 1892-2003 were collected from several sycamores from the eastern shore of Loch Lomond, Scotland, an area with no local point sources of lead emission. The lead concentration and 206Pb/207Pb profiles of the Loch Lomond region cores were compared with corresponding data for the 210Pb-dated loch sediment, and also with data for moss of known age from a Scottish herbarium collection. Two of the seven sycamore cores showed the same lead concentration trend as the lead flux to the loch, the rest having no similarity to either each other or the loch sediment record. Two further sycamore cores showed some similarity in their temporal 206Pb/207Pb trends to those seen in the sediment and moss records, but only in part of their profiles, whilst the 206Pb/207Pb ratios of the other sycamore cores remained relatively unchanged for the majority of the time covered, or exhibited an opposite trend. The 206Pb/207Pb ratios of the tree cores were also mostly higher than those of the previously established records for any given time period. Tree cores covering 1878-2002 were also collected along transects from Wanlockhead and Tyndrum, two areas of former lead mining and smelting associated with distinct 206Pb/207Pb ratios of 1.170 and 1.144, respectively. The Wanlockhead tree cores exhibited a generally decreasing trend in lead concentration with both time and distance from the lead mine. The characteristic 206Pb/207Pb ratio of 1.170 was observed in samples close to the mine but a decrease in the influence of the mine-derived lead was observed in more distant samples. The tree sampled at Tyndrum showed elevated lead concentrations, which decreased with time, and a fairly constant 206Pb/207Pb ratio of 1.15 reflecting input from the mine, features not observed in any other trees along the transect. Overall the data

  18. Helium and lead isotopes reveal the geochemical geometry of the Samoan plume.

    Science.gov (United States)

    Jackson, M G; Hart, S R; Konter, J G; Kurz, M D; Blusztajn, J; Farley, K A

    2014-10-16

    Hotspot lavas erupted at ocean islands exhibit tremendous isotopic variability, indicating that there are numerous mantle components hosted in upwelling mantle plumes that generate volcanism at hotspots like Hawaii and Samoa. However, it is not known how the surface expression of the various geochemical components observed in hotspot volcanoes relates to their spatial distribution within the plume. Here we present a relationship between He and Pb isotopes in Samoan lavas that places severe constraints on the distribution of geochemical species within the plume. The Pb-isotopic compositions of the Samoan lavas reveal several distinct geochemical groups, each corresponding to a different geographic lineament of volcanoes. Each group has a signature associated with one of four mantle endmembers with low (3)He/(4)He: EMII (enriched mantle 2), EMI (enriched mantle 1), HIMU (high µ = (238)U/(204)Pb) and DM (depleted mantle). Critically, these four geochemical groups trend towards a common region of Pb-isotopic space with high (3)He/(4)He. This observation is consistent with several low-(3)He/(4)He components in the plume mixing with a common high-(3)He/(4)He component, but not mixing much with each other. The mixing relationships inferred from the new He and Pb isotopic data provide the clearest picture yet of the geochemical geometry of a mantle plume, and are best explained by a high-(3)He/(4)He plume matrix that hosts, and mixes with, several distinct low-(3)He/(4)He components.

  19. Archaeological reconstruction of medieval lead production: Implications for ancient metal provenance studies and paleopollution tracing by Pb isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Baron, Sandrine, E-mail: baron@lmtg.obs-mip.fr [Laboratoire des Travaux et Recherches Archeologiques sur les Cultures, les Espaces et les Societes, Universite Toulouse 2 Le Mirail, CNRS UMR 5608, Maison de la Recherche, 5 allee Antonio-Machado, 31 058 Toulouse Cedex 09 (France); Centre de Recherches Petrographiques et Geochimiques, Nancy Universite, CNRS UPR 2300, BP 20, 15 rue Notre Dame des Pauvres, 54 501 Vandoeuvre-les-Nancy (France); Le-Carlier, Cecile [Centre de Recherche en Archeologie, Archeosciences, Histoire, Universite Rennes 1, CNRS UMR 6566, Bat 24-25, Campus de Beaulieu 35042 Rennes, Cedex (France); Carignan, Jean; Ploquin, Alain [Centre de Recherches Petrographiques et Geochimiques, Nancy Universite, CNRS UPR 2300, BP 20, 15 rue Notre Dame des Pauvres, 54 501 Vandoeuvre-les-Nancy (France)

    2009-11-15

    The identification of metal provenance is often based on chemical and Pb isotope analyses of materials from the operating chain, mainly ores and metallic artefacts. Such analyses, however, have their limits. Some studies are unable to trace metallic artefacts or ingots to their ore sources, even in well-constrained archaeological contexts. Possible reasons for this difficulty are to be found among a variety of limiting factors: (i) problems of ore signatures, (ii) mixing of different ores (alloys), (iii) the use of additives during the metallurgical process, (iv) metal recycling and (v) possible Pb isotopic fractionation during metal production. This paper focuses on the issue of Pb isotope fractionation during smelting to address the issue of metal provenance. Through an experimental reconstruction of argentiferous Pb production in the medieval period, an attempt was made to better understand and interpret the Pb isotopic composition of ore smelting products. It is shown that the measured differences (outside the total external uncertainties of 0.005 (2*sd) for {sup 206}Pb/{sup 204}Pb ratios) in Pb signatures measured between ores, slag and smoke are not due to Pb mass fractionation processes, but to (1) ore heterogeneity ({Delta}{sup 206}Pb/{sup 204}Pb{sub slag-ores} = 0.066) and (2) the use of additives during the metallurgical process ({Delta}{sup 206}Pb/{sup 204}Pb{sub slag-ores} = 0.083). Even if these differences are due to causes (1) and/or (2), smoke from the ore reduction appears to reflect the ore mining area without a significant disturbance of its Pb signature for all the isotopic ratios ({Delta}{sup 206}Pb/{sup 204}Pb{sub smokes-ores} = 0.026). Thus, because the isotopic heterogeneity of the mining district and additives is averaged in slags, slag appears as the most relevant product to identify ancient metal provenance. Whereas aiming at identifying a given mine seems beyond the possibilities provided by the method, searching for the mining district

  20. Geogenic lead isotope signatures from meat products in Great Britain: Potential for use in food authentication and supply chain traceability

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Jane A.; Pashley, Vanessa [NIGL, BGS, Keyworth, NG12 5GG (United Kingdom); Richards, Gemma J. [School of Veterinary Science, University of Bristol, Bristol BS40 5DU (United Kingdom); Brereton, Nicola [The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ (United Kingdom); Knowles, Toby G. [School of Veterinary Science, University of Bristol, Bristol BS40 5DU (United Kingdom)

    2015-12-15

    This paper presents lead (Pb) isotope data from samples of farm livestock raised in three areas of Britain that have elevated natural Pb levels: Central Wales, the Mendips and the Derbyshire Peak District. This study highlights three important observations; that the Pb found in modern British meat from these three areas is geogenic and shows no clear evidence of modern tetraethyl anthropogenic Pb contribution; that the generally excellent match between the biological samples and the ore field data, particularly for the Mendip and Welsh data, suggests that this technique might be used to provenance biological products to specific ore sites, under favourable conditions; and that modern systems reflect the same process of biosphere averaging that is analogous to cultural focusing in human archaeological studies that is the process of biological averaging leading to an homogenised isotope signature with increasing Pb concentration. - Highlights: • Lead (Pb) isotopes measured in modern British meat were geogenic in origin. • The match indicates that this technique may be used to provenance biological products. • There was no evidence for a contribution from modern anthropogenic Pb sources.

  1. Continuous ice core melter system with discrete sampling for major ion, trace element and stable isotope analyses.

    Science.gov (United States)

    Osterberg, Erich C; Handley, Michael J; Sneed, Sharon B; Mayewski, Paul A; Kreutz, Karl J

    2006-05-15

    We present a novel ice/firn core melter system that uses fraction collectors to collect discrete, high-resolution (32 trace elements by inductively coupled plasma sectorfield mass spectrometry (ICP-SMS), and stable oxygen and hydrogen isotopes by isotope ratio mass spectrometry (IRMS). The new continuous melting with discrete sampling (CMDS) system preserves an archive of each sample, reduces the problem of incomplete particle dissolution in ICP-SMS samples, and provides more precise trace element data than previous ice melter models by using longer ICP-SMS scan times and washing the instrument between samples. CMDS detection limits are similar to or lower than those published for ice melter systems coupled directly to analytical instruments and are suitable for analyses of polar and mid-low-latitude ice cores. Analysis of total calcium and sulfur by ICP-SMS and calcium ion, sulfate, and methanesulfonate by IC from the Mt. Logan Prospector-Russell Col ice core confirms data accuracy and coregistration of the split fractions from each sample. The reproducibility of all data acquired by the CMDS system is confirmed by replicate analyses of parallel sections of the GISP2 D ice core.

  2. Re-estimation of argon isotope ratios leading to a revised estimate of the Boltzmann constant

    Science.gov (United States)

    de Podesta, Michael; Mark, Darren F.; Dymock, Ross C.; Underwood, Robin; Bacquart, Thomas; Sutton, Gavin; Davidson, Stuart; Machin, Graham

    2017-10-01

    In 2013, NPL, SUERC and Cranfield University published an estimate for the Boltzmann constant (de Podesta et al 2013 Metrologia 50 354-76) based on a measurement of the limiting low-pressure speed of sound in argon gas. Subsequently, an extensive investigation by Yang et al (2015 Metrologia 52 S394-409) revealed that there was likely to have been an error in the estimate of the molar mass of the argon used in the experiment. Responding to Yang et al (2015 Metrologia 52 S394-409), de Podesta et al revised their estimate of the molar mass (de Podesta et al 2015 Metrologia 52 S353-63). The shift in the estimated molar mass, and of the estimate of k B, was large:  -2.7 parts in 106, nearly four times the original uncertainty estimate. The work described here was undertaken to understand the cause of this shift and our conclusion is that the original samples were probably contaminated with argon from atmospheric air. In this work we have repeated the measurement reported in de Podesta et al (2013 Metrologia 50 354-76) on the same gas sample that was examined in Yang et al (2015 Metrologia 52 S394-409) and de Podesta et al (2015 Metrologia 52 S353-63). However in this work we have used a different technique for sampling the gas that has allowed us to eliminate the possibility of contamination of the argon samples. We have repeated the sampling procedure three times, and examined samples on two mass spectrometers. This procedure confirms the isotopic ratio estimates of Yang et al (2015 Metrologia 52 S394-409) but with lower uncertainty, particularly in the relative abundance ratio R 38:36. Our new estimate of the molar mass of the argon used in Isotherm 5 in de Podesta et al (2013 Metrologia 50 354-76) is 39.947 727(15) g mol-1 which differs by  +0.50 parts in 106 from the estimate 39.947 707(28) g mol-1 made in de Podesta et al (2015 Metrologia 52 S353-63). This new estimate of the molar mass leads to a revised estimate of the Boltzmann constant of k B

  3. Lead and stable lead isotope ratios in soil, earthworms, and bones of American woodcock (Scolopax minor) from eastern Canada.

    Science.gov (United States)

    Scheuhammer, Anton M; Bond, Della E; Burgess, Neil M; Rodrigue, Jean

    2003-11-01

    A study to discriminate among different possible sources of elevated Pb exposure for American woodcock (Scolopax minor) in eastern Canada is described. Undamaged wing bones excised from young-of-the-year woodcock collected from several locations in southern Ontario, southern Quebec, New Brunswick, and Nova Scotia, Canada, along with soil and earthworm (Aporrectodea tuberculata and Lumbricus rubellus) samples from the same sites, were analyzed for total Pb, and stable Pb isotopes. Ignoring six soil samples with high (> 60 microg/g) Pb concentration from the vicinity of Montreal (QC, Canada), the mean soil-Pb concentration for all sites combined was 19 microg/g (dry wt; n = 64), with a mean 206Pb:207Pb ratio of 1.19, values typical for uncontaminated rural soils in eastern North America. In earthworms, Pb concentrations ranged from 2.4 to 865 (microg/g [dry wt], mean = 24 microg/g). Concentrations of Pb in worms and soils were positively correlated (r = 0.71; p 20 microg/g) had 206Pb:207Pb ratios substantially different from worms and soils sampled from the same areas, even though woodcock feed extensively on soil invertebrates, especially earthworms. The range of 206Pb:207Pb ratios in wing bones of woodcock with elevated Pb exposure was not consistent with exposure to environmental Pb from past gasoline combustion nor Precambrian mining wastes but was consistent with ingestion of spent Pb shotgun pellets.

  4. Effects of organic matter on carbonate stable isotope ratios (δ13C, δ18O values)--implications for analyses of bulk sediments.

    Science.gov (United States)

    Oehlerich, Markus; Baumer, Marlene; Lücke, Andreas; Mayr, Christoph

    2013-03-30

    Stable isotope ratio (δ(13)C, δ(18)O values) analyses of carbonates can be biased by CO(2) release from organic impurities. This is most critical for carbonate isotope analyses from bulk sediments containing comparably high amounts of organic matter (OM). Several methods have been developed to remove OM prior to analyses, but none of them can be universally applied. Moreover, pretreatment methods cause isotopic bias in themselves and should probably best be avoided. Thus, it is essential to have indicators for reliable isotope values of untreated carbonate-OM mixtures. Artificial mixtures of organic compounds with a standard carbonate were analyzed to investigate the bias on carbonate isotope ratios caused by OM in the sample. The total-inorganic-carbon to total-organic-carbon ratio (TIC/TOC) was used as a measure for the " organic impurity" of the sample. The target was to evaluate TIC/TOC as a measure for sample quality and to define TIC/TOC thresholds for reliable isotope measurements of mixtures between calcium carbonate and organic compounds. The effect of organic impurities on carbonate stable isotope values depended on the specific OM compound and the respective TIC/TOC ratio. Different CO(2) release rates were determined for the pure OM compounds. A sample TIC/TOC ratio ≥0.3 was found to be a threshold for reliable measurements of the isotope composition of calcium carbonate. Bulk carbonate analyses from carbonate-OM mixtures are reliable only if the TIC/TOC values do not fall below certain thresholds. This has implications for carbonate isotope studies from bulk sediments for which the TIC/TOC ratios should be considered as an easy-to-determine measure for sample-quality assessment. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Sulfate-water isotope geothermometry and lead isotope data for the regional geothermal system in the Twin Falls area, south-central Idaho

    Science.gov (United States)

    Mariner, R.H.; Young, H.W.; Bullen, T.D.; Janik, C.J.; ,

    1997-01-01

    Sulfate-water isotope geothermometry for the geothermal system at Twin Falls, Idaho indicates aquifer-temperatures of 90?? to 106 ??C; most sites are between 90?? and 93 ??C. 206Pb/204pb and 280Pb/204Pb of individual thermal waters are principally a function of how much lead has been dissolved from the carbonate and silicate fractions of the Paleozoic limestone collected west of Grand View Peak. Although most thermal waters are recovered from Tertiary rhyolite, very little of the dissolved lead is from the rhyolite. Recharge to this system occurs in northern Nevada and the fluid moves northward in the Paleozoic limestones. The occurrence of thermal fluid in the Idavada Volcanics near and south of Twin Falls, Idaho is the result of upward movement of this fluid from the Paleozoic limestone.

  6. Isotopic characterisation of lead in contaminated soils from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Jeffrey R. [Macaulay Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom)]. E-mail: j.bacon@macaulay.ac.uk; Dinev, Nikolai S. [N Poushkarov Institute of Soil Science and Agroecology, Sofia (Bulgaria)

    2005-03-01

    Soil samples from the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria contained very high concentrations of cadmium, lead and zinc (up to 140, 4900 and 5900 mg kg{sup -1}, respectively). A roadside soil in a relatively uncontaminated area also contained high concentrations of the same metals (24, 1550 and 1870 mg kg{sup -1}, respectively) indicating that the transport of ores could be a source of contamination. Even though the lead isotope ratios in all the samples fell within a very narrow range (for example, 1.186-1.195 for {sup 206}Pb/{sup 207}Pb), the samples could be differentiated into three distinct groups: ores ({sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios of 1.1874-1.1884 and 2.4755-2.4807, respectively), current deposition (1.1864 and 2.4704-2.4711, respectively) and local background (1.1927-1.1951 and 2.4772-2.4809, respectively). Although most of the current deposition has its origin in the ores used at the smelter, up to 12% could be from other sources such as petrol lead. - Although soils in the vicinity of a non-ferrous metal smelter near Plovdiv, Bulgaria, have become highly contaminated with the ores used, lead isotope analysis has revealed that up to 12% of current deposition could be from other sources such as petrol lead.

  7. Trophic structure of mesopelagic fishes in the Gulf of Mexico revealed by gut content and stable isotope analyses

    Science.gov (United States)

    McClain-Counts, Jennifer P.; Demopoulos, Amanda W.J.; Ross, Steve W.

    2017-01-01

    Mesopelagic fishes represent an important component of the marine food web due to their global distributions, high abundances and ability to transport organic material throughout a large part of the water column. This study combined stable isotope (SIAs) and gut content analyses (GCAs) to characterize the trophic structure of mesopelagic fishes in the North-Central Gulf of Mexico. Additionally, this study examined whether mesopelagic fishes utilized chemosynthetic energy from cold seeps. Specimens were collected (9–25 August 2007) over three deep (>1,000 m) cold seeps at discrete depths (surface to 1,503 m) over the diurnal cycle. GCA classified 31 species (five families) of mesopelagic fishes into five feeding guilds: piscivores, large crustacean consumers, copepod consumers, generalists and mixed zooplanktivores. However, these guilds were less clearly defined based on stable isotope mixing model (MixSIAR) results, suggesting diets may be more mixed over longer time periods (weeks–months) and across co-occurring species. Copepods were likely important for the majority of mesopelagic fishes, consistent with GCA (this study) and previous literature. MixSIAR results also identified non-crustacean prey items, including salps and pteropods, as potentially important prey items for mesopelagic fishes, including those fishes not analysed in GCA (Sternoptyx spp. and Melamphaidae). Salps and other soft-bodied species are often missed in GCAs. Mesopelagic fishes had δ13C results consistent with particulate organic matter serving as the baseline organic carbon source, fueling up to three trophic levels. Fishes that undergo diel vertical migration were depleted in 15N relative to weak migrators, consistent with depth-specific isotope trends in sources and consumers, and assimilation of 15N-depleted organic matter in surface waters. Linear correlations between fish size and δ15N values suggested ontogenetic changes in fish diets for several species. While there was

  8. Lead isotope evidence for a young formation age of the Earth-Moon system

    Science.gov (United States)

    Connelly, J. N.; Bizzarro, M.

    2016-10-01

    A model of a giant impact between two planetary bodies is widely accepted to account for the Earth-Moon system. Despite the importance of this event for understanding early Earth evolution and the inventory of Earth's volatiles critical to life, the timing of the impact is poorly constrained. We explore a data-based, two-stage Pb isotope evolution model in which the timing of the loss of volatile Pb relative to refractory U in the aftermath of the giant impact is faithfully recorded in the Pb isotopes of bulk silicate Earth. Constraining the first stage Pb isotopic evolution permits calculating an age range of 4.426-4.417 Ga for the inflection in the U/Pb ratio related to the giant impact. This model is supported by Pb isotope data for angrite meteorites that we use to demonstrate volatility-driven, planetary-scale Pb loss was an efficient process during the early Solar System. The revised age is ∼100 Myr younger than most current estimates for the age of the Moon but fully consistent with recent ages for lunar ferroan anorthosite and the timing of Earth's first crust inferred from the terrestrial zircon record. The estimated loss of ∼98% of terrestrial Pb relative to the Solar System bulk composition by the end of the Moon-forming process implies that the current inventory of Earth's most volatile elements, including water, arrived during post-impact veneering by volatile-rich bodies.

  9. Coupled study of radionuclides and stable lead isotopes in Western Mediterranean; Etude couplee des radionucleides et des isotopes stables du plomb en Mediterranee occidentale

    Energy Technology Data Exchange (ETDEWEB)

    Miralles, J

    2004-05-15

    The aim of this work is to identified an environmental deposit able to have stored the atmospheric signal over large time-scale leaning our investigations on lead stable isotopes ({sup 206}Pb, {sup 207}Pb, {sup 208}Pb) and radionuclide ({sup 210}Pb, {sup 137}Cs, {sup 239}Pu, {sup 240}Pu) analysis. Owing to prior studies on anthropogenic lead sources, emission intensity and sedimentary accumulation, we choose to investigate the marine sediments of the Western Mediterranean. In the Gulf of Lions, the sedimentary accumulation is 110 {+-} 7 {mu}g.cm{sup -2} high in good agreement with the atmospheric inventory estimate we made from salt marshes of Camargue (99 {mu}g.cm{sup -2}). The reconstructed lead accumulation through a modelling step coupling {sup 210}Pb and stable isotopes corroborates the regional anthropogenic emissions (Ferrand, 1996). Briefly, in this context of the marine sediments are a relevant proxy to study past lead atmospheric concentration over the last hundred years. In the Alboran Sea, the study area is less constrained and more complex in terms of climatic, meteorological and hydrological conditions. The sedimentary inventory is of 153 {+-} 47 {mu}g.cm{sup -2}, 1,5 higher than in the margin sediments of the Gulf of Lions. The analysis of aerosols, sediments and settling particles evidences a continuity between the atmospheric signal and the sedimentary record. In spite of this encouraging results, the knowledge of the Alboran system is still too restricted in order to unambiguously conclude on accuracy of deep marine sediments of this area to study past atmospheric fallouts. (author)

  10. Lead isotope evidence for recent uranium mobility in geological formations of Brazil: implications for radioactive waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, S.S. [Department of Physics and Astronomy, University of Calgary, Calgary (Canada); Babinski, M. [Instituto de Geociencias, Universidade de Sao Paulo, Sao Paulo (Brazil); Marinho, M.M. [Companhia Baiana de Pesquisa Mineral (CBPM), Salvador (Brazil); Barbosa, J.S.F. [Instituto de Geociencias, Universidade Federal da Bahia, Salvador (Brazil); Sato, I.M.; Salvador, V.L. [Instituto de Pesquisas Energeticas e Nucleares (CNEN/SP), Sao Paulo (Brazil)

    1999-03-01

    Lead-lead isotope data from whole rock samples are used to investigate the recent (last few million years) mobility of U and Th. The method is based on the comparison of the calculated present day U and Th concentrations required to yield the Pb isotope composition in the samples with the actual present day concentrations of U and Th obtained by direct measurement. The geological formations studied include the Neoproterozoic carbonate sediments of the Bambui Group, Archean/Paleoproterozoic granite-greenstone terrain of the Contendas-Mirante Complex and a Proterozoic ortho-gneisses hosting U deposit in Lagoa Real. All these formations are in the Sao Francisco Craton, Brazil. The data show high U mobility in the carbonate sediments and in the deformed ortho-gneisses set in a ductile shear zone. Infiltration of groundwater through fault zones seems to have facilitated the U mobility. The Pb isotope approach is a useful technique complementing U-series disequilibrium studies and may be included for site characterization studies for radioactive waste disposal. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. Point processes statistics of stable isotopes: analysing water uptake patterns in a mixed stand of Aleppo pine and Holm oak

    Directory of Open Access Journals (Sweden)

    Carles Comas

    2015-04-01

    Full Text Available Aim of study: Understanding inter- and intra-specific competition for water is crucial in drought-prone environments. However, little is known about the spatial interdependencies for water uptake among individuals in mixed stands. The aim of this work was to compare water uptake patterns during a drought episode in two common Mediterranean tree species, Quercus ilex L. and Pinus halepensis Mill., using the isotope composition of xylem water (δ18O, δ2H as hydrological marker. Area of study: The study was performed in a mixed stand, sampling a total of 33 oaks and 78 pines (plot area= 888 m2. We tested the hypothesis that both species uptake water differentially along the soil profile, thus showing different levels of tree-to-tree interdependency, depending on whether neighbouring trees belong to one species or the other. Material and Methods: We used pair-correlation functions to study intra-specific point-tree configurations and the bivariate pair correlation function to analyse the inter-specific spatial configuration. Moreover, the isotopic composition of xylem water was analysed as a mark point pattern. Main results: Values for Q. ilex (δ18O = –5.3 ± 0.2‰, δ2H = –54.3 ± 0.7‰ were significantly lower than for P. halepensis (δ18O = –1.2 ± 0.2‰, δ2H = –25.1 ± 0.8‰, pointing to a greater contribution of deeper soil layers for water uptake by Q. ilex. Research highlights: Point-process analyses revealed spatial intra-specific dependencies among neighbouring pines, showing neither oak-oak nor oak-pine interactions. This supports niche segregation for water uptake between the two species.

  12. Stable isotope analyses reveal the importance of seagrass beds as feeding areas for juvenile Myrophis punctatus (Angulliformes: Ophichthidae) inthe coastal waters of Florida

    Science.gov (United States)

    The feeding habits and habitats of the speckled worm eel Myrophis punctatus were studied on the mangrove edge of the Indian River Lagoon (Florida) using stomach contents and stable isotope analyses of carbon (δ13C) and nitrogen (δ15N). Stomach dietary analyses identified four tax...

  13. Signs of malnutrition and starvation--reconstruction of nutritional life histories by serial isotopic analyses of hair.

    Science.gov (United States)

    Neuberger, Ferdinand M; Jopp, Eilin; Graw, Matthias; Püschel, Klaus; Grupe, Gisela

    2013-03-10

    The diagnosis of starvation in children or adults is an important topic in paediatric and geriatric medicine, and in law assessment. To date, few reliable techniques are available to reconstruct the onset and duration of undernourishment, especially in cases of wilful neglect or abuse. The intention of this research project is to introduce a method based on isotopic analysis to reconstruct nutritional life histories and to detect starvation. For this purpose the specific signature of stable carbon and nitrogen isotopes in human hair samples is investigated and measured in the course of serious nutritional deprivation. Previous study of our research group on anorectic patients has shown that incremental hair analyses can monitor the individual nutritional status of each patient. Increasing δ(15)N-values indicate the catabolism of bodily protein and are associated with a very low BMI. In contrast, the changes of the δ(13)C values and BMI were in phase, which can be linked to the lack of energy in the consumed diet and the break down of body fat deposits. These findings were now applied to various forensic cases, in which severe starvation occurred recently prior to death. We are aiming at establishing an unbiased biomarker to identify the individual timeframe of nutritional deprivation to detect and prevent starvation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  14. Sources of variability and comparability between salmonid stomach contents and isotopic analyses: study design lessons and recommendations

    Science.gov (United States)

    Vinson, M.R.; Budy, P.

    2011-01-01

    We compared sources of variability and cost in paired stomach content and stable isotope samples from three salmonid species collected in September 2001–2005 and describe the relative information provided by each method in terms of measuring diet overlap and food web study design. Based on diet analyses, diet overlap among brown trout, rainbow trout, and mountain whitefish was high, and we observed little variation in diets among years. In contrast, for sample sizes n ≥ 25, 95% confidence interval (CI) around mean δ15Ν and δ13C for the three target species did not overlap, and species, year, and fish size effects were significantly different, implying that these species likely consumed similar prey but in different proportions. Stable isotope processing costs were US$12 per sample, while stomach content analysis costs averaged US$25.49 ± $2.91 (95% CI) and ranged from US$1.50 for an empty stomach to US$291.50 for a sample with 2330 items. Precision in both δ15Ν and δ13C and mean diet overlap values based on stomach contents increased considerably up to a sample size of n = 10 and plateaued around n = 25, with little further increase in precision.

  15. Patterns of juvenile habitat use by the spider crab Maja brachydactyla as revealed by stable isotope analyses

    Directory of Open Access Journals (Sweden)

    Juan Freire

    2009-03-01

    Full Text Available Patterns of habitat use by spider crab juveniles, Maja brachydactyla, from two geographic areas on the NW coast of the Iberian Peninsula were studied through the analysis of carbon and nitrogen stable isotope relations in muscle and hepatopancreas. Main potential preys of spider crab juveniles in rocky and sandy habitats and different organic matter sources in coastal food webs were also analysed. Isotopic ratios showed no difference between rocky and sandy habitats. The use of carapace colour and epibiosis as an indicator of habitat use was not supported by our data. These results suggest that movements between the two habitats are much more frequent than suggested in previous studies. In the coastal food web, two main trophic compartments were identified according to their organic matter source: one based on plankton and seaweeds (rocky habitats, and one based on sedimentary particulate organic matter (sandy bottoms. By means of the model of Phillips and Gregg (2003, it was found that juveniles of Maja brachydactyla from both habitats consumed approximately two thirds of the preys in rocky habitats and one third in sedimentary habitats. The results indicate that in exposed environments large juveniles spend most of the time on sedimentary bottoms, where they find more refuge, moving frequently to nearby rocky substrates to feed.

  16. Stable isotope analyses of oxygen (18O:17O:16O) and chlorine (37Cl:35Cl) in perchlorate: reference materials, calibrations, methods, and interferences

    Science.gov (United States)

    Böhlke, John Karl; Mroczkowski, Stanley J.; Sturchio, Neil C.; Heraty, Linnea J.; Richman, Kent W.; Sullivan, Donald B.; Griffith, Kris N.; Gu, Baohua; Hatzinger, Paul B.

    2017-01-01

    RationalePerchlorate (ClO4−) is a common trace constituent of water, soils, and plants; it has both natural and synthetic sources and is subject to biodegradation. The stable isotope ratios of Cl and O provide three independent quantities for ClO4− source attribution and natural attenuation studies: δ37Cl, δ18O, and δ17O (or Δ17O or 17Δ) values. Documented reference materials, calibration schemes, methods, and interferences will improve the reliability of such studies.MethodsThree large batches of KClO4 with contrasting isotopic compositions were synthesized and analyzed against VSMOW-SLAP, atmospheric O2, and international nitrate and chloride reference materials. Three analytical methods were tested for O isotopes: conversion of ClO4− to CO for continuous-flow IRMS (CO-CFIRMS), decomposition to O2 for dual-inlet IRMS (O2-DIIRMS), and decomposition to O2 with molecular-sieve trap (O2-DIIRMS+T). For Cl isotopes, KCl produced by thermal decomposition of KClO4 was reprecipitated as AgCl and converted into CH3Cl for DIIRMS.ResultsKClO4 isotopic reference materials (USGS37, USGS38, USGS39) represent a wide range of Cl and O isotopic compositions, including non-mass-dependent O isotopic variation. Isotopic fractionation and exchange can affect O isotope analyses of ClO4− depending on the decomposition method. Routine analyses can be adjusted for such effects by normalization, using reference materials prepared and analyzed as samples. Analytical errors caused by SO42−, NO3−, ReO42−, and C-bearing contaminants include isotope mixing and fractionation effects on CO and O2, plus direct interference from CO2 in the mass spectrometer. The results highlight the importance of effective purification of ClO4− from environmental samples.ConclusionsKClO4 reference materials are available for testing methods and calibrating isotopic data for ClO4− and other substances with widely varying Cl or O isotopic compositions. Current ClO4−extraction, purification

  17. Novel stable isotope analyses demonstrate significant rates of glucose cycling in mouse pancreatic islets.

    Science.gov (United States)

    Wall, Martha L; Pound, Lynley D; Trenary, Irina; O'Brien, Richard M; Young, Jamey D

    2015-06-01

    A polymorphism located in the G6PC2 gene, which encodes an islet-specific glucose-6-phosphatase catalytic subunit, is the most important common determinant of variations in fasting blood glucose (FBG) levels in humans. Studies of G6pc2 knockout (KO) mice suggest that G6pc2 represents a negative regulator of basal glucose-stimulated insulin secretion (GSIS) that acts by hydrolyzing glucose-6-phosphate (G6P), thereby reducing glycolytic flux. However, this conclusion conflicts with the very low estimates for the rate of glucose cycling in pancreatic islets, as assessed using radioisotopes. We have reassessed the rate of glucose cycling in pancreatic islets using a novel stable isotope method. The data show much higher levels of glucose cycling than previously reported. In 5 mmol/L glucose, islets from C57BL/6J chow-fed mice cycled ∼16% of net glucose uptake. The cycling rate was further increased at 11 mmol/L glucose. Similar cycling rates were observed using islets from high fat-fed mice. Importantly, glucose cycling was abolished in G6pc2 KO mouse islets, confirming that G6pc2 opposes the action of the glucose sensor glucokinase by hydrolyzing G6P. The demonstration of high rates of glucose cycling in pancreatic islets explains why G6pc2 deletion enhances GSIS and why variants in G6PC2 affect FBG in humans. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  18. Microfacies Analyses and Carbon Isotope Studies on Lower Triassic Microbialites from Armenia

    Science.gov (United States)

    Friesenbichler, Evelyn; Baud, Aymon; Krystyn, Leopold; Sahakyan, Lilit; Richoz, Sylvain

    2016-04-01

    After the end-Permian mass extinction the upper Paleozoic skeletal carbonate factory was abruptly replaced by a non-skeletal carbonate factory and Permian-Triassic boundary microbialites (PTBMs) were flourishing. These PTBMs were abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents and were present during at least four events in the Lower Triassic. The investigated PTBMs from three different sites in southern Armenia were formed in a distal open marine setting on a pelagic carbonate ramp. They grew during two microbial growth phases in Griesbachian times, whereas the microbialites from the first microbial growth phase co-occur with calcium carbonate crystal fans (CCFs). The microbes formed predominantly thrombolites that vary in size between 5 cm to 1.5 m. The biggest thrombolite has a cone-shaped build-up geometry and an asymmetrical growth, which indicates the influence of a steady bottom current. It consists of numerous thrombolite domes with a top head diameter of up to 8 m width and a total height of up to 12 m. The microbialites are surrounded by a bioclastic wackestone that mainly contains ostracods, foraminifers, microgastropods, thin-shelled bivalves and sponges. Carbon isotope studies were performed on both the microbialites and the surrounding sediment. A comparison between the δ13C values of the microbialites and the surrounding sediment revealed that there is little difference (<0.4‰) between these values in the microbialites that formed during the second microbial growth phase. In contrast, the microbialites and CCFs from the first microbial growth phase show differences in the δ13C values of up to 2.3‰ , which could be due to microbial activity.

  19. Lithium isotope separation by laser

    Energy Technology Data Exchange (ETDEWEB)

    Arisawa, T.; Maruyama, Y.; Suzuki, Y.; Shiba, K.

    1982-01-01

    A lithium isotope separation was performed using a laser isotope separation method. It was found that the lithium atoms with a natural isotopic abundance enhanced its /sup 6/Li concentration up to over 90% by tuning the laser wavelength to the /sup 2/Psub(1/2) of /sup 6/Li. Too high power, however, leads to a loss of enrichment due to the power broadening effect which was analysed by the equation of motion of density matrices.

  20. Specificity of synthesis and analysis of molecules labelled with stable isotopes; Specificite des syntheses et analyses des molecules marquees avec les isotopes stables

    Energy Technology Data Exchange (ETDEWEB)

    Noel, J.P. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Biologie Cellulaire et Moleculaire

    1994-12-31

    The various specificities of synthesis with stable isotopes are: unusual raw materials and use of precursors, possibility of producing several isotopomers corresponding to the same chemical compound, involvement of a reaction mechanism in labelling. As a matter of fact, isotopic synthesis are generally more complex than synthesis of non-labelled products. When preparing labelled molecules, it is of importance to avoid any isotopic dilution. Chemical purity for labelled molecules is controlled by various chromatographic techniques and isotopic analysis are carried out by nuclear magnetic resonance and mass spectrometry. 9 figs., 2 tabs.

  1. Uranium-lead Isotope Evidence in the Shelyabinsk LL5 Chondrite Meteorite for Ancient and Recent Thermal Events

    Science.gov (United States)

    Lapen, T. J.; Kring, D. A.; Zolensky, M. E.; Andreasen, R.; Righter, M.; Swindle, T. D.; Beard, S. P.; Swindle, T. D.

    2014-01-01

    The impact histories on chondrite parent bodies can be deduced from thermochronologic analyses of materials and isotope systems with distinct apparent closure temperatures. It is especially critical to better understand the geological histories and physical properties of potenally hazardous near-Earth asteroids. Chelyabinsk is an LL5 chondrite meteorite that was dispersed over a wide area tens of kilometers south of the town of Chelyabinsk, Russia by an explosion at an altitude of 27 km at 3:22 UT on 15 Feb 2013 [1,2]. The explosion resulted in significant damage to surrounding areas and over 1500 injuries along with meteorite fragments being spread over a wide area [1].

  2. Lead Isotope Compositions of Acid Residues from Olivine-Phyric Shergottite Tissint: Implications for Heterogeneous Shergottite Source Reservoirs

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2015-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions and trace element abundances. These correlations have been interpreted as indicating the presence of a reduced, incompatible element- depleted reservoir and an oxidized, incompatible- element-enriched reservoir. The former is clearly a depleted mantle source, but there is ongoing debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former requires the ancient Martian crust to be the enriched source (crustal assimilation), whereas the latter requires isolation of a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and trace element concentration analyses of sequential acid-leaching fractions (leachates and the final residues) from the geochemically depleted olivine-phyric shergottite Tissint. The results suggest that the Tissint magma is not isotopically uniform and sampled at least two geochemical source reservoirs, implying that either crustal assimilation or magma mixing would have played a role in the Tissint petrogenesis.

  3. Spatial Distribution of Lead Isotope Ratios and Inorganic Element Concentrations in Epiphytic Lichens from the Athabasca Oil Sands Region

    Science.gov (United States)

    Graney, J. R.; Landis, M. S.; Puckett, K.; Edgerton, E.; Krupa, S.; Percy, K.

    2013-12-01

    Coupled studies of inorganic element concentrations and lead (Pb) isotope ratios have been conducted on Hypogymnia physodes samples collected in the Athabasca Oil Sands Region (AOSR) in Alberta, Canada in 2002, 2008, and 2011. To investigate the spatial extent of air emissions, the lichens were collected from sites as far as 160 km from the mining and processing operations. 30 milligram sub-samples of the lichens were microwave digested, and the extracts were analyzed using DRC-ICPMS to determine elemental concentrations, and sector field ICPMS to measure Pb isotope ratios. Concentrations of elements in the lichens were found to reflect proximity to mining and oil processing sites as well as topography, ecosystem differences, and the metabolic biogeochemistry of the lichens. An exponential decrease in concentration of metals associated with fugitive dust (aluminum and others) versus distance from the mining sites, suggests elevated coarse particle emissions associated with mining operations. Near source concentrations of metals with an oil signature (vanadium and others) are less enhanced and more homogeneous than the metals in the fugitive dust, reflecting emission and deposition of smaller diameter particles at greater distances from oil processing sources. The mining and oil processing signatures are superimposed over elemental concentrations that reflect the nutrient needs of the lichens. These findings are being confirmed through ongoing studies using dichot samplers to collect coarse and fine particulate aerosol samples. The lichen samples collected beyond 50 km from the mining and processing sites cluster into a Pb isotope grouping with a 207Pb / 206Pb ratio of 0.8650 and a 208Pb / 206Pb ratio near 2.095. This grouping likely reflects the regional background Pb isotope ratio signature. 207Pb / 206Pb and 208Pb / 206Pb ratios decrease as one nears the mining and processing operations. This indicates that other Pb source(s), (e.g. Pb in the bitumen from the oil

  4. Isotopic identification of natural vs. anthropogenic lead sources in marine sediments from the inner Ria de Vigo (NW Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Iglesias, P., E-mail: palvarez@uvigo.es [Department of Marine Geosciences and Land Use Management, Faculty of Marine Sciences, University of Vigo (Spain); Laboratorio de Analisis Quimico Instrumental, C.A.C.T.I., Universidad de Vigo (Spain); Rubio, B., E-mail: brubio@uvigo.es [Department of Marine Geosciences and Land Use Management, Faculty of Marine Sciences, University of Vigo (Spain); Millos, J., E-mail: jmillos@uvigo.es [Laboratorio de Analisis Quimico Instrumental, C.A.C.T.I., Universidad de Vigo (Spain)

    2012-10-15

    San Simon Bay, the inner part of the Ria de Vigo (NW Spain), an area previously identified as highly polluted by Pb, was selected for the application of Pb stable isotope ratios as a fingerprinting tool in subtidal and intertidal sediment cores. Lead isotopic ratios were determined by inductively coupled plasma mass spectrometry on extracts from bulk samples after total acid digestion. Depth-wise profiles of {sup 206}Pb/{sup 207}Pb, {sup 206}Pb/{sup 204}Pb, {sup 207}Pb/{sup 204}Pb, {sup 208}Pb/{sup 204}Pb and {sup 208}Pb/{sup 207}Pb ratios showed, in general, an upward decrease for both intertidal and subtidal sediments as a consequence of the anthropogenic activities over the last century, or centuries. Waste channel samples from a nearby ceramic factory showed characteristic Pb stable isotope ratios different from those typical of coal and petrol. Natural isotope ratios from non-polluted samples were established for the study area, differentiating sediments from granitic or schist-gneiss sources. A binary mixing model employed on the polluted samples allowed estimating the anthropogenic inputs to the bay. These inputs represented between 25 and 98% of Pb inputs in intertidal samples, and 9-84% in subtidal samples, their contributions varying with time. Anthropogenic sources were apportioned according to a three-source model. Coal combustion-related emissions were the main anthropogenic source Pb to the bay (60-70%) before the establishment of the ceramic factory in the area (in the 1970s) which has since constituted the main source (95-100%), followed by petrol-related emissions. The Pb inputs history for the intertidal area was determined for the 20th century, and, for the subtidal area, the 19th and 20th centuries. -- Highlights: Black-Right-Pointing-Pointer Pb stable isotope ratios were applied to study Pb sources in coastal sediments. Black-Right-Pointing-Pointer Pb isotopic ratios were determined for pre-pollution and for industrial samples. Black

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

    Science.gov (United States)

    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.

  6. Lead isotope signatures of Kerguelen plume-derived olivine-hosted melt inclusions: Constraints on the ocean island basalt petrogenesis

    Science.gov (United States)

    Borisova, Anastassia Y.; Faure, François; Deloule, Etienne; Grégoire, Michel; Béjina, Frédéric; de Parseval, Philippe; Devidal, Jean-Luc

    2014-06-01

    The nature of magmatic sources reflected by isotopic composition of the ocean island basalt (OIB) remains an on-going question in igneous geochemistry. To constrain the magmatic sources for OIB related to the Kerguelen plume activity, we performed detailed microanalytical investigation of the 21.4 Ma picritic basalt (MD109-D6-87) dredged during the “Marion Dufresne” cruise on a seamount between Kerguelen Archipelago and Heard Island. Lead isotope compositions of olivine-hosted melt inclusions and matrix glasses were measured by Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS). We also performed major and trace element microanalyses and mapping of the inclusions and the host olivine phenocrysts by electron microprobe (wavelength-dispersive X-ray spectroscopy, WDS). The observed significant major element (K2O/P2O5, Al2O3/TiO2) and Pb isotope (207Pb/206Pb and 208Pb/206Pb) heterogeneities of parental melts (MgO = 7-10 wt.%) during early high pressure crystallisation stage (200-300 MPa, Fo82-86 mol%), and relative homogeneity at later lower-pressure crystallisation stage ( 4), Al2O3/TiO2 (> 4) ratios are attributed to assimilation of the plateau basaltic crust (≥ 50 wt.%) by the melts in the magma chamber at palaeodepths from 6 to 9 km. The crustal assimilation may have happened through plagioclase dissolution. The large chemical and isotopic heterogeneity of the parental OIB melts found by in situ microanalyses in this study suggests that the bulk rock chemistry alone cannot provide enough information to constrain the nature of the magmatic sources.

  7. Lead isotopes and the sources of the Columbia River Basalt Group

    Science.gov (United States)

    Chamberlain, V. E.; Lambert, R. St. J.

    1994-06-01

    A detailed study of Pb-208/Pb-204, Pb-207/Pb-204, and Pb-206/Pb-204 ratios suggests that the number of Pb isotopic reservoirs required for the Columbia River Basalt Group (CRBG) (as currently defined) must be increased from the presently accepted four to at least six. The identities of the six reservoirs are two of mid-ocean ridge basalt (MORB) slightly contaminated with sediment (R1 and R2, R1 being 'Cascades' PB); one a probable plume component (R3); two of unspecified mantle material but probably of R1 type, contaminated with local crustal Pb (R4 and R5); and the sixth a complex enriched reservoir of 2150 Ma age (R6). R1 is an end-member for all CRBG, except the Saddle Mountains Basalts. R2 is a second end-member for the Picture Gorge Basalt and CRBG, except the Saddle Mountains Basalts. R2 is a second end-member for the Picture Gorge Basalt and appears to be unique to it. R3 is the principal source for most of the Wanapum Basalt, as well as for most of the chemically evolved portions of the Grande Ronde Basalt. Volumetric and tectonic considerations require that one source of the CRBG be a plume or, at least, a nonlocal crustal or uppermost mantle source, and R3 is the ideal candidate for that role. R4 is the second source for the Imnaha Basalt, and R5 is the source for the (206)Pb-rich varieties of the Grande Ronde Basalt. R4 and R5 are identified with contamination by local Phanerozoic crust because of their similarity to local crustal Pb and because the rocks which contain them also have Cu contents correlated with their Pb isotopic compositions. R6 is the parent for Pb in all the Saddle Mountain Basalts. This last source appears to have been homogeneous 2150 m.y. ago but has since split into a number of separate, discrete pockets, each with its own characteristic Pb isotopic signature. Some of these appear in individual Saddle Mountain Basalt flows, while other sources have mixed with R4 to produce individual Saddle Mountain Basalt flows of the Ice Harbor

  8. [High-precision in situ analysis of the lead isotopic composition in copper using femtosecond laser ablation MC-ICP-MS and the application in ancient coins].

    Science.gov (United States)

    Chen, Kai-Yun; Fan, Chao; Yuan, Hong-Lin; Bao, Zhi-An; Zong, Chun-Lei; Dai, Meng-Ning; Ling, Xue; Yang, Ying

    2013-05-01

    In the present study we set up a femtosecond laser ablation MC-ICP-MS method for lead isotopic analysis. Pb isotopic composition of fifteen copper (brass, bronze) standard samples from the National Institute of Standards Material were analyzed using the solution method (MC-ICP-MS) and laser method (fLA-MC-ICPMS) respectively, the results showed that the Pb isotopic composition in CuPb12 (GBW02137) is very homogeneous, and can be used as external reference material for Pb isotopic in situ analysis. On CuPb12 112 fLA-MC-ICPMS Pb isotope analysis, the weighted average values of the Pb isotopic ratio are in good agreement with the results analyzed by bulk solution method within 2sigma error, the internal precision RSEs of the 208 Pb/204 Pb ratio and 207 Pb/206 Pb ratio are less than 90 and 40 ppm respectively, and the external precision RSDs of them are less than 60 and 30 ppm respectively. Pb isotope of thirteen ancient bronze coins was analyzed via fLA-MC-ICPMS, the results showed that the Pb isotopic composition of ancient coins of different dynasties is significantly different, and not all the Pb isotopic compositions in the coins even from the same dynasty are in agreement with each other.

  9. Combined U-Pb and Lu-Hf isotope analyses by laser ablation MC-ICP-MS: methodology and applications

    Directory of Open Access Journals (Sweden)

    Massimo Matteini

    2010-06-01

    Full Text Available The Lutetium-Hafnium isotopic system represents one of the most innovative and powerful tools for geochronology and isotopic studies. Combined U-Pb and Lu-Hf in situ analyses on zircon by LA-MC-ICP-MS permit to characterize isotopically the host magma from which it crystallized furnishing significant information for sediment provenance and crustal evolution studies. In this paper e describe the Lu-Hf systematic by LA-MC-ICP-MS developed in the laboratory of Geochronology of the University of Brasilia and report the results obtained by repeated analyses of 176Hf/177Hf isotopic ratio of three zircon standards: GJ-1 = 0.282022 ± 11 (n=56, Temora 2 = 0.282693 ± 14 (n=25 and UQZ = 0.282127 ± 33 (n=11. The 176Hf/177Hf ratio (0.282352 ± 22, n=14 of gem quality zircon used as in-house standard have been also characterized. As a geological application, we analyzed two complex zircons selected from a migmatitic rocks from the Borborema Province, NE Brazil. On the basis of U-Pb and Lu-Hf data, two main crystallization events have been identified in both studied zircons. An older event at ca. 2.05 Ga recognized in the inherited cores represents a well-characterized paleoproterozoic magmatic event that affected the whole Borborema Province. A second crystallization event at ~ 575 Ma, recognized at the rims, represents a Neoproterozoic (Brazilian high grade metamorphic-magmatic event.O sistema isotópico Lutécio-Hafnio representa uma das ferramentas mais recentes e poderosas para estudos isotópicos e geocronológicos. Análises combinadas in situ de U-Pb e Lu-Hf sobre zircão pelo LA-MC-ICP-MS permitem caracterizar iso-topicamente o magma onde ele cristalizou, fornecendo valiosas informações para estudos de proveniência de sedimento e de evolução crustal. Nesse trabalho descrevemos a sistemática de Lu-Hf pelo LA-MC-ICP-MS implantada no laboratório de Geocronologia da Universidade de Brasília e reportamos os resultados obtidos de repetidas an

  10. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    Science.gov (United States)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0–20, 20–40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0–20 cm = 1492.4 gC m2 and 20–40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  11. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses.

    Science.gov (United States)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ(13)C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m(2) and 20-40 cm = 1770.6 gC m(2)) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  12. Lead

    Science.gov (United States)

    ... found? Who is at risk? What are the health effects of lead? Get educational material about lead Get certified as a Lead Abatement Worker, or other abatement discipline Lead in drinking water Lead air pollution Test your child Check and maintain your home ...

  13. SIMS analyses of silicon and oxygen isotope ratios for quartz from Archean and Paleoproterozoic banded iron formations

    Science.gov (United States)

    Heck, Philipp R.; Huberty, Jason M.; Kita, Noriko T.; Ushikubo, Takayuki; Kozdon, Reinhard; Valley, John W.

    2011-10-01

    Banded iron formations (BIFs) are chemical marine sediments dominantly composed of alternating iron-rich (oxide, carbonate, sulfide) and silicon-rich (chert, jasper) layers. Isotope ratios of iron, carbon, and sulfur in BIF iron-bearing minerals are biosignatures that reflect microbial cycling for these elements in BIFs. While much attention has focused on iron, banded iron formations are equally banded silica formations. Thus, silicon isotope ratios for quartz can provide insight on the sources and cycling of silicon in BIFs. BIFs are banded by definition, and microlaminae, or sub-mm banding, are characteristic of many BIFs. In situ microanalysis including secondary ion mass spectrometry is well-suited for analyzing such small features. In this study we used a CAMECA IMS-1280 ion microprobe to obtain highly accurate (±0.3‰) and spatially resolved (˜10 μm spot size) analyses of silicon and oxygen isotope ratios for quartz from several well known BIFs: Isua, southwest Greenland (˜3.8 Ga); Hamersley Group, Western Australia (˜2.5 Ga); Transvaal Group, South Africa (˜2.5 Ga); and Biwabik Iron Formation, Minnesota, USA (˜1.9 Ga). Values of δ 18O range from +7.9‰ to +27.5‰ and include the highest reported δ 18O values for BIF quartz. Values of δ 30Si have a range of ˜5‰ from -3.7‰ to +1.2‰ and extend to the lowest δ 30Si values for Precambrian cherts. Isua BIF samples are homogeneous in δ 18O to ±0.3‰ at mm- to cm-scale, but are heterogeneous in δ 30Si up to 3‰, similar to the range in δ 30Si found in BIFs that have not experienced high temperature metamorphism (up to 300 °C). Values of δ 30Si for quartz are homogeneous to ±0.3‰ in individual sub-mm laminae, but vary by up to 3‰ between multiple laminae over mm-to-cm of vertical banding. The scale of exchange for Si in quartz in BIFs is thus limited to the size of microlaminae, or less than ˜1 mm. We interpret differences in δ 30Si between microlaminae as preserved from primary

  14. Trace metal concentrations and lead isotopic composition in surface waters of the Northeast Pacific along the United States - Mexico boundary

    Energy Technology Data Exchange (ETDEWEB)

    Sanudo-Wilhelmy, S. (Inst. of Marine Science, Santa Cruz, CA (United States))

    1990-01-09

    To evaluate the magnitude of heavy metal contamination along the United States - Mexico boundary, trace metal concentrations (Pb, Cd, Mn, Fe, and Zn) and lead isotopic composition ([sup 204]Pb, [sup 206]Pb, [sup 207]Pb, and [sup 208]Pb) were measured along four surface water transects across the continental shelf off the Baja California Coast. The stations were located between 2 to 45 km offshore, including both coastal and open ocean locations. All the metal distributions along the transects were characterized by offshore concentration gradients. The highest trace metal concentrations occurred in coastal waters in association with high salinities and nutrient concentrations. There was also a longshore gradient in trace metal concentrations. Trace element concentrations were lower in the southern locations than along the United States - Mexico boundary, and were comparable to typical open ocean values. The relative enrichment of metals in surface waters off the northern part of Baja California was primarily associated with advection/upwelling processes, not with anthropogenic inputs. Mass balance calculations indicated that about 1% of Cd and 13% of Zn were from urban discharges. The low metal levels measured in coastal waters off the central part of Baja California were attributed to the intrusion of open ocean waters, based on hydrographic data, satellite images and lead isotopic compositions.

  15. Food web functioning of the benthopelagic community in a deep-sea seamount based on diet and stable isotope analyses

    Science.gov (United States)

    Preciado, Izaskun; Cartes, Joan E.; Punzón, Antonio; Frutos, Inmaculada; López-López, Lucía; Serrano, Alberto

    2017-03-01

    Trophic interactions in the deep-sea fish community of the Galicia Bank seamount (NE Atlantic) were inferred by using stomach contents analyses (SCA) and stable isotope analyses (SIA) of 27 fish species and their main prey items. Samples were collected during three surveys performed in 2009, 2010 and 2011 between 625 and 1800 m depth. Three main trophic guilds were determined using SCA data: pelagic, benthopelagic and benthic feeders, respectively. Vertically migrating macrozooplankton and meso-bathypelagic shrimps were identified to play a key role as pelagic prey for the deep sea fish community of the Galicia Bank. Habitat overlap was hardly detected; as a matter of fact, when species coexisted most of them evidenced a low dietary overlap, indicating a high degree of resource partitioning. A high potential competition, however, was observed among benthopelagic feeders, i.e.: Etmopterus spinax, Hoplostethus mediterraneus and Epigonus telescopus. A significant correlation was found between δ15N and δ13C for all the analysed species. When calculating Trophic Levels (TLs) for the main fish species, using both the SCA and SIA approaches, some discrepancies arose: TLs calculated from SIA were significantly higher than those obtained from SCA, probably indicating a higher consumption of benthic-suprabenthic prey in the previous months. During the summer, food web functioning in the Galicia Bank was more influenced by the assemblages dwelling in the water column than by deep-sea benthos, which was rather scarce in the summer samples. These discrepancies demonstrate the importance of using both approaches, SCA (snapshot of diet) and SIA (assimilated food in previous months), when attempting trophic studies, if an overview of food web dynamics in different compartments of the ecosystem is to be obtained.

  16. Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany

    Directory of Open Access Journals (Sweden)

    B. Winterholler

    2008-05-01

    Full Text Available Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles.

    Primary aerosol particles retain the original isotopic signature of their source. The isotopic composition of secondary sulfates depends on the isotopic composition of precursor SO2 and the oxidation process. The fractionation with respect to the source SO2 is −9‰ for homogeneous and +16.5‰ for heterogeneous oxidation. The sulfur isotope ratio of secondary sulfate particles can therefore be used to identify the oxidation pathway by which this sulfate was formed. With the new single particle technique, different types of primary and secondary sulfates were first identified based on their chemical composition, and then their individual isotopic signature was measured separately. Our samples were collected in Mainz, Germany, in an urban environment. Secondary sulfates (ammonium sulfate, gypsum, mixed sulfates and coatings on silicates or organic aerosol dominated sulfate loadings in our samples. Comparison of the chemical and isotopic composition of secondary sulfates showed that the isotopic composition was homogeneous, independent of the chemical composition. This is typical for particles that derive from in-cloud processing. The isotopic composition of the source SO2 of secondary sulfates was calculated based on the isotopic composition of particles with known oxidation pathway and showed a strong dependence on wind direction. The contribution of heterogeneous

  17. Metal enrichment and lead isotope analysis for source apportionment in the urban dust and rural surface soil.

    Science.gov (United States)

    Yu, Yang; Li, Yingxia; Li, Ben; Shen, Zhenyao; Stenstrom, Michael K

    2016-09-01

    To understand the metal accumulation in the environment and identify its sources, 29 different metal contents and lead (Pb) isotope ratios were determined for 40 urban dust samples, 36 surface soil samples, and one river sediment sample collected in the municipality of Beijing, China. Results showed that cadmium, copper (Cu), mercury, Pb, antimony (Sb), and zinc demonstrated to be the typical urban contaminants and mostly influenced by the adjacent human activities with higher content to background ratios and SD values. Among the 29 metal elements investigated, Cu and Sb were found to be the most distinct elements that were highly affected by the developing level and congestion status of the cities with much higher contents in dust in more developed and congested cities. There was a relatively wider range of Pb isotope ratios of country surface soil than those of urban dust. The results of source identification based on Pb isotope ratios showed that coal combustion was the first largest Pb source and vehicle exhaust was the second largest source. The sum of them accounted for 74.6% mass proportion of overall Pb pollution on average. The surface soil sample collected at an iron mine had the highest (204)Pb/(206)Pb, (207)Pb/(206)Pb, and (208)Pb/(206)Pb ratios indicating ore had much higher ratios than other sources. The fine particle subsamples had higher (204)Pb/(206)Pb, (207)Pb/(206)Pb, and (208)Pb/(206)Pb ratios than the coarse particle subsamples indicating more anthropogenic sources of coal combustion and vehicle exhaust for fine particles and more background influence for coarse particles. These results help with pinpointing the major Pb sources and applying suitable measures for the target sources.

  18. Lead isotopes and trace metal ratios of aerosols as tracers of Pb pollution sources in Kanpur, India

    Science.gov (United States)

    Sen, Indra; Bizimis, Michael; Tripathi, Sachchida; Paul, Debajyoti; Tyagi, Swati; Sengupta, Deep

    2015-04-01

    The anthropogenic flux of Pb in the Earth's surface is almost an order of magnitude higher than its corresponding natural flux [1]. Identifying the sources and pathways of anthropogenic Pb in environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb- isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, an industrial city in northern India. The Pb concentration in the airborne particulate matter varies between 14-216 ng/m3, while the other heavy metals vary by factor of 10 or less, e.g. Cd=0.3-3 ng/m3, As=0.4-3.5 ng/m3, Zn=36-161 ng/m3, and Cu=3-22 ng/m3. The 206Pb/207Pb, 208Pb/206Pb, and 208Pb/207Pb vary between 1.112 - 1.129, 2.123-2.141, and 2.409-2.424 respectively, and are highly correlated with each other (R2>0.9). Pb isotopes and trace metal data reveals that coal combustion is the major source of anthropogenic Pb in the atmosphere, with limited contribution from mining and smelting processes. We further conclude that combination of Pb isotope ratios and V/Pb ratios are powerful tracers for Pb source apportionment studies, which is otherwise difficult to differentiate based only on Pb systematics [1] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol.(46), 8601-8609

  19. Estimation of lead sources in a Japanese cedar ecosystem using stable isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Yuko [Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687 (Japan)]. E-mail: yuko106@ffpri.affrc.go.jp; Noguchi, Kyotaro [Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687 (Japan); Takahashi, Masamichi [Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687 (Japan); Okamoto, Toru [Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687 (Japan); Yoshinaga, Shuichiro [Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687 (Japan)

    2007-06-15

    Anthropogenic Pb affects the environment worldwide. To understand its effect on forest ecosystem, Pb isotope ratios were determined in precipitation, various components of vegetation, the forest floor, soil and parent material in a Japanese cedar (Cryptomeria japonica D. Don) forest stand. The average {sup 206}Pb/{sup 207}Pb ratio in bulk precipitation was 1.14 {+-} 0.01 (mean {+-} SD), whereas that in the subsoil (20-130 cm) was 1.18 {+-} 0.01. Intermediate ratios ranging from 1.15 to 1.16 were observed in the vegetation, the forest floor, and the surface soil (0-10 cm). Using the {sup 206}Pb/{sup 207}Pb ratios, the contribution of anthropogenic sources to Pb accumulated in the forest were estimated by the simple binary mixing model. Sixty-two percent of the Pb in the forest floor, 71% in the vegetation, and 55% in the surface soil (0-10 cm) originated from anthropogenic sources, but only 16% in the sub-surface soil (10-20 cm) was anthropogenic. These results suggest that internal Pb cycling occurs mainly between surface soil and vegetation in a Japanese cedar ecosystem, and that anthropogenic Pb strongly influences Pb cycling. Although the Japanese cedar ecosystem has a shallow forest floor, very little atmospherically derived Pb migrated downward over 10 cm in depth.

  20. Temporal evolution of lead isotope ratios in sediments of the Central Portuguese Margin: a fingerprint of human activities.

    Science.gov (United States)

    Mil-Homens, Mário; Caetano, Miguel; Costa, Ana M; Lebreiro, Susana; Richter, Thomas; de Stigter, Henko; Trancoso, Maria A; Brito, Pedro

    2013-09-15

    Stable Pb isotope ratios ((206)Pb/(207)Pb, (208)Pb/(206)Pb), (210)Pb, Pb, Al, Ca, Fe, Mn and Si concentrations were measured in 7 sediment cores from the west coast of the Iberian Peninsula to assess the Pb contamination throughout the last 200 years. Independently of their locations, all cores are characterized by increasing Pb/Al rends not related to grain-size changes. Conversely, decreasing trends of (206)Pb/(207)Pb were found towards the present. This tendency suggest a change in Pb sources reflecting an increased proportion derived from anthropogenic activities. The highest anthropogenic Pb inventories for sediments younger than 1950s were found in the two shallowest cores of Cascais and Lisboa submarine canyons, reflecting the proximity of the Tagus estuary. Lead isotope signatures also help demonstrate that sediments contaminated with Pb are not constrained to estuarine-coastal areas and upper parts of submarine canyons, but are also to transferred to a lesser extent to deeper parts of the Portuguese Margin. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Preliminary lead isotope investigations of brine from the Red Sea, Galena from the Kingdom of Saudi Arabia, and galena from United Arab Republic (Egypt)

    Science.gov (United States)

    Delevaux, M.H.; Doe, B.R.; Brown, G.F.

    1967-01-01

    The isotopic composition of lead in Red Sea chloride brine containing 0.5 ppm Pb is found to be similar to that of some Cenozoic ore leads such as galena at Rabigh in Saudi Arabia that may have formed during mineralization accompanying Tertiary rifting. Bir Ranga galena in Miocene sediments from United Arab Republic (Egypt) is also isotopically similar to lead in Red Sea brine. The chlorine brine must be considered a possible mineralizing fluid. Lead isotopes show promise for use in mineral prospect evaluation in that galena from Samrah is isotopically similar to that from Mahd adh Dhahab, which has been the only ore producer in Saudi Arabia since 1945. Drilling at Samrah does indicate a possible economic mineralization. The lead isotope data coupled with available geologic knowledge and geochronometry are used to tentatively divide the ore prospects of the Kingdom of Saudi Arabia into relative categories of mineralization age. Two Mesozoic and Cenozoic mineralizations are distinguished on the basis of a 207Pb/204Pb difference; an early Paleozoic mineralization grouping is outlined; and a late Precambrian mineralization period is suggested. ?? 1967.

  2. Stable isotopes of lead and strontium as tracers of sources of airborne particulate matter in Kyrgyzstan.

    Science.gov (United States)

    Central Asia is dominated by an arid climate and desert-like conditions, leading to the potential of long-range transport of desert dust. One potential source of dust to Central Asia is the Aral Sea, the surface area of which has receded in size from 68,000 km2 to 14,280 km2, lar...

  3. Functional connectivity of coral reef fishes in a tropical seascape assessed by compound-specific stable isotope analyses

    KAUST Repository

    McMahon, Kelton W.

    2011-01-01

    The ecological integrity of tropical habitats, including mangroves, seagrass beds and coral reefs, is coming under increasing pressure from human activities. Many coral reef fish species are thought to use mangroves and seagrass beds as juvenile nurseries before migrating to coral reefs as adults. Identifying essential habitats and preserving functional linkages among these habitats is likely necessary to promote ecosystem health and sustainable fisheries on coral reefs. This necessitates quantitative assessment of functional connectivity among essential habitats at the seascape level. This thesis presents the development and first application of a method for tracking fish migration using amino acid (AA) δ13C analysis in otoliths. In a controlled feeding experiment with fish reared on isotopically distinct diets, we showed that essential AAs exhibited minimal trophic fractionation between consumer and diet, providing a δ13C record of the baseline isoscape. We explored the potential for geochemical signatures in otoliths of snapper to act as natural tags of residency in seagrass beds, mangroves and coral reefs in the Red Sea, Caribbean Sea and Eastern Pacific Ocean. The δ13C values of otolith essential AAs varied as a function of habitat type and provided a better tracer of residence in juvenile nursery habitats than conventional bulk stable isotope analyses (SIA). Using our otolith AA SIA approach, we quantified the relative contribution of coastal wetlands and reef habitats to Lutjanus ehrenbergii populations on coastal, shelf and oceanic coral reefs in the Red Sea. L. ehrenbergii made significant ontogenetic migrations, traveling more than 30 km from juvenile nurseries to coral reefs and across deep open water. Coastal wetlands were important nurseries for L. ehrenbergii; however, there was significant plasticity in L. ehrenbergii juvenile habitat requirements. Seascape configuration played an important role in determining the functional connectivity of L

  4. Using multi-scale stable isotopes analyses to study the microbial processes of soil organic matter stabilization

    Science.gov (United States)

    Hatton, P.; Remusat, L.; Zeller, B.; Bode, S.; Brewer, E.; Boeckx, P. F.; Derrien, D.

    2012-12-01

    Soil microorganisms are increasingly recognized as important drivers for the stabilization of soil organic matter (OM) with soil assemblages, but the way they act remains not fully explored. Here, we used a multi-scale approach to investigate the attachment of microbial products with soil organo-mineral assemblages. A surface acidic Cambisol was amended with 13C15N labeled glycine and leaf fragments prior to sequential density separation of plant debris, aggregates and non-aggregates mineral grains with little OM attached. Labels were tracked using elemental analyzer coupled to isotope ratio mass spectrometry (EA-IRMS), liquid chromatography (LC) coupled to IRMS and nano-scale secondary ions MS (NanoSIMS). After 8h of glycine incubation, the comparison between γ-irradiated and non-sterile soils revealed that more than 90% and 85% of the stabilized glycine-derived 13C and 15N were found in microbial products, with a higher occurrence in aggregates than in plant debris and mineral grains. NanoSIMS images showed that these stabilized microbial products are principally not confined to the microbial cells, but evenly spread at the surface of the mineral-attached OM as extracellular products. After calibration, the comparison of their C/N ratios with the C/N ratios of the corresponding soil particles suggested that the microbial products are stabilized through physico-chemical interactions most likely mediated by the reactivity of the underlying minerals. Unlike NanoSIMS, LC-IRMS analyses allow the tracing of 13C tracers within microbial biomasses using amino sugars as biomarkers. After 3 months of incubation, freshly produced amino sugars deriving from the readily accessible glycine and finely ground leaf fragments clearly peaked in microbial aggregates and plant debris, respectively. Differences in distributions indicated that bacteria and fungi both grow where the resource is, but accumulate in microbial aggregates. These results suggested either a higher

  5. EDXS and XRD Analyses of Coleus with Different Concentration Selenium Supplements Under Lead Stress

    Directory of Open Access Journals (Sweden)

    QIN Hui-yuan

    2014-04-01

    Full Text Available In order to study the changes of the morphologies and element composition in Coleus hlumei Benth(Coleusroots and leaves under1.0 mmol·L-1 Pb2+ stress with selenium ( Setreatments, and to preliminarily investigate the relief mechanism of Se level on lead toxicity from the perspective of spectroscopy, Coleus was cultivated in nutrient solutions with different concentrations of Se. The results showed that the content of C, K and Ca elements in roots decreased, while 0, Mg, Al, Si, Fe and Pb elements increased under Pb stress with Se treatments. In addi-tion, the content of C, Mg, Al, Si, K, Ca and Fe elements in leaves decreased, while 0 and Cl elements increased. The element species and its contents in roots were changed obviously under Pb stress with Se treatments, and crystalline solid and crystal phase in roots were correspond-ingly changed.

  6. Uranium-lead dating method at the Pará-Iso isotope geology laboratory, UFPA, Belém - Brazil

    Directory of Open Access Journals (Sweden)

    Robert S. Krymsky

    2007-03-01

    Full Text Available Analytical procedures for U-Pb isotope dilution analyses at the Pará-Iso isotope geology laboratory of the Federal University of Pará (UFPA are described in detail. The procedures are applied to zircon, titanite, rutile, apatite, columbite-tantalite and whole rock. Reagent preparation and chemical processing are done in clean-room conditions. Samples are dissolved using TeflonTM microcapsules in steel jacket TeflonTM Parr InstrumentTM bomb or TeflonTM screw cap containers. U and Pb are separated using anion exchange AG 1x8 resin columns. Typical blanks for mineral sample amounts of 0.01 to 1.0 mg are less than 1 pg U and 20-30 pg Pb. Isotope analysis of the U and Pb from the same filament are carried out using a Finnigan MAT 262 mass-spectrometer in static and dynamic modes. The current analytical level is demonstrated on analyses of international standard zircon 91500 with three different 235U-205Pb and 235U-208Pb isotope tracers and whole rock standards. Results of analyses of two zircon samples are also presented.Os procedimentos analíticos para análises U-Pb por diluição isotópica no Laboratório de Geologia Isotópica (Pará-Iso da Universidade Federal do Pará (UFPA são descritos detalhadamente. Esses procedimentos são aplicados para análises de zircão, titanita, rutilo, apatita, columbita-tantalita e rocha total. A purificação dos reagentes e os procedimentos químicos são feitos em salas limpas. As amostras são dissolvidas em microcápsulas de Teflon em bombas do tipo Parr InstrumentTM. U e Pb são separados em colunas com resina de troca iônica AG 1x8. Os brancos de procedimento para amostra típica(0,01-1 mg são menores que 1 pg de U e 20-30 pg de Pb. As análises isotópicas de Pb e de U são feitas em um único filamento de Re em um espectrômetro de massa Finnigan MAT 262 nos modos estático e dinâmico. O nível analítico atual é comprovado pelas análises do padrão internacional de zircão 91500, usando tr

  7. Using lead isotopes and trace element records from two contrasting Lake Tanganyika sediment cores to assess watershed – Lake exchange

    Science.gov (United States)

    Odigie, Kingsley; Cohen, A.D.; Swarzenski, Peter W.; Flegal, R

    2014-01-01

    Lead isotopic and trace element records of two contrasting sediment cores were examined to reconstruct historic, industrial contaminant inputs to Lake Tanganyika, Africa. Observed fluxes of Co, Cu, Mn, Ni, Pb, and Zn in age-dated sediments collected from the lake varied both spatially and temporally over the past two to four centuries. The fluxes of trace elements were lower (up to 10-fold) at a mid-lake site (MC1) than at a nearshore site (LT-98-58), which is directly downstream from the Kahama and Nyasanga River watersheds and adjacent to the relatively pristine Gombe Stream National Park. Trace element fluxes at that nearshore site did not measurably change over the last two centuries (1815–1998), while the distal, mid-lake site exhibited substantial changes in the fluxes of trace elements – likely caused by changes in land use – over that period. For example, the flux of Pb increased by ∼300% from 1871 to 1991. That apparent accelerated weathering and detrital mobilization of lithogenic trace elements was further evidenced by (i) positive correlations (r = 0.77–0.99, p < 0.05) between the fluxes of Co, Cu, Mn, Ni, Pb, and Zn and those of iron (Fe) at both sites, (ii) positive correlations (r = 0.82–0.98, p < 0.01, n = 9) between the fluxes of elements (Al, Co, Cu, Fe, Mn, Ni, Pb, and Zn) and the mass accumulation rates at the offshore site, (iii) the low enrichment factors (EF < 5) of those trace elements, and (iv) the temporal consistencies of the isotopic composition of Pb in the sediment. These measurements indicate that accelerated weathering, rather than industrialization, accounts for most of the increases in trace element fluxes to Lake Tanganyika in spite of the development of mining and smelting operations within the lake’s watershed over the past century. The data also indicate that the mid-lake site is a much more sensitive and useful recorder of environmental changes than the nearshore site. Furthermore, the lead isotopic compositions

  8. Lead isotope ratios in six lake sediment cores from Japan Archipelago: Historical record of trans-boundary pollution sources

    Energy Technology Data Exchange (ETDEWEB)

    Hosono, Takahiro, E-mail: hosono@kumamoto-u.ac.jp [Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Alvarez, Kelly [Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kuwae, Michinobu [Senior Research Fellow Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)

    2016-07-15

    Sediment cores from six lakes situated from north to south on the Japanese Archipelago were collected during 2009–2010 to investigate the hypothesis that deposition of lead (Pb) was coming from East Asia (including China, South Korea and eastern part of Russia). Accumulation rates and ages of the lake sediment were estimated by the {sup 210}Pb constant rate of supply model and {sup 137}Cs inputs to reconstruct the historical trends of Pb accumulation. Cores from four lakes located in the north and central Japan, showed clear evidence of Pb pollution with a change in the {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios in the recent sediment as compared to the deeper sediment. Among the six studied lakes, significant inputs of anthropogenic lead emissions were observed at Lake Mikazuki (north Hokkaido in north Japan), Lake Chokai (north of Honshu), and Lake Mikuriga (central part of Honshu). Pb isotopic comparison of collected core sediment and previously reported data for wet precipitation and aerosols from different Asian regions indicate that, before 1900, Pb accumulated in these three lakes was not affected by trans-boundary sources. Lake Mikazuki started to receive Pb emissions from Russia in early 1900s, and during the last two decades, this lake has been affected by trans-boundary Pb pollution from northern China. Lake Chokai has received Pb pollutant from northern China since early 1900s until 2009, whereas for the Lake Mikuriga the major Pb contaminant was transported from southern China during the past 100 years. The results of our study demonstrate that Japan Archipelago has received trans-boundary Pb emissions from different parts of East Asian region depending on location, and the major source region has changed historically. - Highlights: • Historical trend of Pb pollution was recorded in six Japanese Lakes. • Pb concentration and Pb isotope ratios were determined for sediment cores. • High [Pb] and less radiogenic Pb isotope ratios

  9. Automated method for simultaneous lead and strontium isotopic analysis applied to rainwater samples and airborne particulate filters (PM10).

    Science.gov (United States)

    Beltrán, Blanca; Avivar, Jessica; Mola, Montserrat; Ferrer, Laura; Cerdà, Víctor; Leal, Luz O

    2013-09-03

    A new automated, sensitive, and fast system for the simultaneous online isolation and preconcentration of lead and strontium by sorption on a microcolumn packed with Sr-resin using an inductively coupled plasma mass spectrometry (ICP-MS) detector was developed, hyphenating lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA). Pb and Sr are directly retained on the sorbent column and eluted with a solution of 0.05 mol L(-1) ammonium oxalate. The detection limits achieved were 0.04 ng for lead and 0.03 ng for strontium. Mass calibration curves were used since the proposed system allows the use of different sample volumes for preconcentration. Mass linear working ranges were between 0.13 and 50 ng and 0.1 and 50 ng for lead and strontium, respectively. The repeatability of the method, expressed as RSD, was 2.1% and 2.7% for Pb and Sr, respectively. Environmental samples such as rainwater and airborne particulate (PM10) filters as well as a certified reference material SLRS-4 (river water) were satisfactorily analyzed obtaining recoveries between 90 and 110% for both elements. The main features of the LOV-MSFIA-ICP-MS system proposed are the capability to renew solid phase extraction at will in a fully automated way, the remarkable stability of the column which can be reused up to 160 times, and the potential to perform isotopic analysis.

  10. Spliced leader-based metatranscriptomic analyses lead to recognition of hidden genomic features in dinoflagellates.

    Science.gov (United States)

    Lin, Senjie; Zhang, Huan; Zhuang, Yunyun; Tran, Bao; Gill, John

    2010-11-16

    Environmental transcriptomics (metatranscriptomics) for a specific lineage of eukaryotic microbes (e.g., Dinoflagellata) would be instrumental for unraveling the genetic mechanisms by which these microbes respond to the natural environment, but it has not been exploited because of technical difficulties. Using the recently discovered dinoflagellate mRNA-specific spliced leader as a selective primer, we constructed cDNA libraries (e-cDNAs) from one marine and two freshwater plankton assemblages. Small-scale sequencing of the e-cDNAs revealed functionally diverse transcriptomes proven to be of dinoflagellate origin. A set of dinoflagellate common genes and transcripts of dominant dinoflagellate species were identified. Further analyses of the dataset prompted us to delve into the existing, largely unannotated dinoflagellate EST datasets (DinoEST). Consequently, all four nucleosome core histones, two histone modification proteins, and a nucleosome assembly protein were detected, clearly indicating the presence of nucleosome-like machinery long thought not to exist in dinoflagellates. The isolation of rhodopsin from taxonomically and ecotypically diverse dinoflagellates and its structural similarity and phylogenetic affinity to xanthorhodopsin suggest a common genetic potential in dinoflagellates to use solar energy nonphotosynthetically. Furthermore, we found 55 cytoplasmic ribosomal proteins (RPs) from the e-cDNAs and 24 more from DinoEST, showing that the dinoflagellate phylum possesses all 79 eukaryotic RPs. Our results suggest that a sophisticated eukaryotic molecular machine operates in dinoflagellates that likely encodes many more unsuspected physiological capabilities and, meanwhile, demonstrate that unique spliced leaders are useful for profiling lineage-specific microbial transcriptomes in situ.

  11. Thermo-Mechanical Analyses of the High Heat Flux Component for ITER Dual Functional Lithium Lead Test Blanket Module

    Institute of Scientific and Technical Information of China (English)

    CHEN Hongli; BAI Yunqing

    2009-01-01

    The finite element code ANSYS is used to calculate the temperature and stress distributions for the first wall of DFLL-TBM (dual functional lithium lead-test blanket module),for testing in ITER. Preliminary analyses indicate that not only the low temperature design rules,the well-known 3Sm rules, are satisfied for the first wall, but the additional high temperature structural design criteria for the creep damage limits and creep-ratcheting limits are met as well.

  12. Lead isotopes and heavy minerals analyzed as tools to understand the distribution of lead and other potentially toxic elements in soils contaminated by Cu smelting (Legnica, Poland).

    Science.gov (United States)

    Tyszka, Rafał; Pietranik, Anna; Kierczak, Jakub; Ettler, Vojtěch; Mihaljevič, Martin; Medyńska-Juraszek, Agnieszka

    2016-12-01

    Surroundings of the Legnica Cu smelter (Poland) offer insight into the behavior of Pb and other metal(oid)s in heavily contaminated soils in a relatively simple site, where lithogenic and anthropogenic Pb contributions have uniform Pb isotope composition over the time of smelter activity. Distribution of metal(oid)s decreases asymptotically with depth and below 30 cm reaches concentrations typical or lower than those of upper continental crust. Usually, such distribution is interpreted as the decrease in anthropogenic Pb contribution with depth. However, calculations based on Pb isotopes indicate that anthropogenic Pb is probably distributed both as Pb-rich particles of slags and fly ashes and Pb-poor soil solutions. Generally, anthropogenic Pb constitutes up to 100 % of Pb in the uppermost 10 cm of the soils and comes often from mechanical mixing with slag and fly ash particles as well as their weathering products. On the other hand, lower soil horizon contains anthropogenic Pb in various forms, and at depths below 30 cm, most of anthropogenic Pb comes from soil solutions and can constitute from 1 to 65 % of the Pb budget. This is consistent with secondary electron microscope (SEM) analyses of heavy mineral particles showing that, in upper horizons, Pb, Cu, and Zn are contained in various particles emitted from the smelter, which show different stages of weathering. Currently, large portion of these metals may reside in the secondary Fe-hydro-oxides. On the other hand, in deeper soil horizons, anthropogenic Pb is probably dominated by Pb coming from leaching of slag or fly ash particles. Overall, metal(oid) mobility is a dynamic process and is controlled by the soil type (cultivated versus forest) and the composition and the structure of the metal-rich particles emitted from the smelter. High proportions of anthropogenic Pb at depths below 30 cm in some soil profiles indicate that Pb (and probably other metal(oid)s) can be transported down the soil profile

  13. Uranium-lead isotopic ages from the Sierra Nevada Batholith, California

    Science.gov (United States)

    Chen, James H.; Moore, James G.

    1982-06-01

    all in the range 99±3 m.y., indicating a relatively short period of emplacement and cooling for this nested group of plutons. U-Pb ages of a mafic inclusion and its host granodiorite indicate that both were derived from a common source or that the mafic inclusion was totally equilibrated with the granodioritic magma. Comparison of isotopic ages determined by different methods such as zircon U-Pb, sphene U-Pb, hornblende K-Ar, and biotite K-Ar suggests that zircon U-Pb ages generally approximate the emplacement age of a pluton. However, some plutons probably contain inherited or entrained old zircons, and the zircons of some samples are disturbed by younger thermal and metamorphic events. The ages reported here are consistent with U-Pb age determinations previously made on granitic rocks to the north [Stern et al., 1981], The age distribution of granitic belts determined here is in general agreement with those established by K-Ar dating [Evernden and Kistler, 1970] but does not differentiate the five epochs of plutonism determined in their study.

  14. Lead isotopes in soils and groundwaters as tracers of the impact of human activities on the surface environment: The Domizio-Flegreo Littoral (Italy) case study

    Science.gov (United States)

    Grezzi, G.; Ayuso, R.A.; de Vivo, B.; Lima, A.; Albanese, S.

    2011-01-01

    The isotopic signature of geogenic and anthropogenic materials, in combination with concentration data for pollutants, can help trace the origin and the extent of contamination in the environment. This approach is particularly effective if naturally occurring and anthropogenically introduced metals have different isotopic ratios. Lead isotope analysis on soils from 7 profiles (1. m depth) and on groundwaters from 8 wells have been used to determine the impact of human activities on the surface environment of Domizio-Flegreo Littoral. Result obtained show that in sub-rural areas the isotopic composition of the samples collected along the soil profiles of Domizio-Flegreo Littoral is likely mostly controlled by the nature of the parent geologic material (natural) while in more urbanized areas (Giugliano) Pb isotopic composition in superficial soils is mostly influenced by anthropic sources such as motor vehicles. Lead isotopic ratios in groundwaters also show that the use of pesticides and, probably, the influence of aerosols and the presence of illegal waste disposal can influence water quality. ?? 2010 Elsevier B.V.

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

    Science.gov (United States)

    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 (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

  16. A Martian Fractionation Line Constructed from Oxygen Isotope Analyses of Bulk Material and Minerals from SNC Meteorites

    Science.gov (United States)

    Banerjee, N. R.; Ali, A.; Jabeen, I.; Osinski, G.; Al-Rawas, A. D.; Nasir, S.; Flemming, R.; Shivak, J.; Gregory, D.

    2013-09-01

    Precise triple oxygen isotope data of SNC Martian meteorites are obtained by laser-assisted fluorination technique. Martian fractionation line is constructed using bulk material and mineral separates of SNC meteorites.

  17. Multiple isotope analyses of the pike tapeworm Triaenophorus nodulosus reveal peculiarities in consumer-diet discrimination patterns.

    Science.gov (United States)

    Behrmann-Godel, J; Yohannes, E

    2015-03-01

    Previous studies of dietary isotope discrimination have led to the general expectation that a consumer will exhibit enriched stable isotope levels relative to its diet. Parasite-host systems are specific consumer-diet pairs in which the consumer (parasite) feeds exclusively on one dietary source: host tissue. However, the small numbers of studies previously carried out on isotopic discrimination in parasite-host (ΔXP-HT) systems have yielded controversial results, showing some parasites to be isotopically depleted relative to their food source, while others are enriched or in equilibrium with their hosts. Although the mechanism for these deviations from expectations remains to be understood, possible influences of specific feeding niche or selection for only a few nutritional components by the parasite are discussed. ΔXP-HT for multiple isotopes (δ13C, δ15N, δ34S) were measured in the pike tapeworm Triaenophorus nodulosus and two of its life-cycle fish hosts, perch Perca fluviatilis and pike Esox lucius, within which T. nodulosus occupies different feeding locations. Variability in the value of ΔXP-HT calculated for the parasite and its different hosts indicates an influence of feeding location on isotopic discrimination. In perch liver ΔXP-HT was relatively more negative for all three stable isotopes. In pike gut ΔXP-HT was more positive for δ13C, as expected in conventional consumer-diet systems. For parasites feeding on pike gut, however, the δ15N and δ34S isotope values were comparable with those of the host. We discuss potential causes of these deviations from expectations, including the effect of specific parasite feeding niches, and conclude that ΔXP-HT should be critically evaluated for trophic interactions between parasite and host before general patterns are assumed.

  18. Lead

    Science.gov (United States)

    ... Chapter 6 Chapter 7 Chapter 8 Chapter 9 Appendix I Appendix II Tables Figures State Programs Alabama Alaska Arizona ... Tool Kit Resources Healthy Homes and Lead Poisoning Prevention Training Center (HHLPPTC) Training Tracks File Formats Help: ...

  19. Mineralogic, fluid inclusion, and sulfur isotope evidence for the genesis of Sechangi lead-zinc (-copper) deposit, Eastern Iran

    Science.gov (United States)

    Malekzadeh Shafaroudi, Azadeh; Karimpour, Mohammad Hassan

    2015-07-01

    The Sechangi lead-zinc (-copper) deposit lies in the Lut block metallogenic province of Eastern Iran. This deposit consists of ore-bearing vein emplaced along fault zone and hosted by Late Eocene monzonite porphyry. Hydrothermal alteration minerals developed in the wall rock include quartz, kaolinite, illite, and calcite. Microscopic studies reveal that the vein contains galena and sphalerite with minor chalcopyrite and pyrite as hypogene minerals and cerussite, anglesite, covellite, malachite, hematite, and goethite as secondary minerals. Fluorite and quartz are the dominant gangue minerals and show a close relationship with sulfide mineralization. Calculated δ34S values for the ore fluid vary between -9.9‰ and -5.9‰. Sulfur isotopic compositions suggest that the ore-forming aqueous solutions were derived from magmatic source and mixed with isotopically light sulfur, probably leached from the volcanic and plutonic country rocks. Microthermometric study of fluid inclusions indicates homogenization temperatures of 151-352 °C. Salinities of ore-forming fluids ranged from 0.2 to 16.5 wt.% NaCl equivalent. The ore-forming fluids of the Sechangi deposit are medium- to low-temperature and salinity. Fluid mixing may have played an important role during Pb-Zn (-Cu) mineralization. The key factors allowing for metal transport and precipitation during ore formation include the sourcing of magmatic fluids with high contents of metallogenic elements and the mixing of these hydrothermal fluids with meteoric waters resulting in the formation of deposit. In terms of the genetic type of deposit, the Sechangi is classified as a volcanic-subvolcanic hydrothermal-related vein deposit.

  20. Study on hydrogen isotopes permeation in fluidized state of liquid lithium-lead

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, S.; Yoshimura, R.; Okada, M.; Fukada, S.; Edao, Y. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-shi, Fukuoka (Japan)

    2015-03-15

    Lithium-lead (Li-Pb) is one of the most promising candidate materials for the liquid blanket of fusion reactors. Hydrogen transfer under a fluidized condition of Li-Pb is investigated experimentally to design a Li-Pb blanket system. Li-Pb eutectic alloy flows inside a Ni tube in the experimental system, where H{sub 2} permeates into and out of the forced Li-Pb flow. The overall H{sub 2} permeation rate is analyzed using a mass balance model. Hydrogen atoms diffuse in Ni and Li-Pb. The steady-state H{sub 2} permeation rate obtained by this experiment is smaller than the result of the calculation model. A resistance factor is introduced to the present analysis in order to evaluate the influence of other H{sub 2} transfer mechanisms, such as diffusion in Li-Pb and dissolution reaction between Ni and Li-Pb. The contribution of the resistance to the overall H{sub 2} permeation rate becomes large when the flow rate of Li-Pb is low. This is because the boundary layer thickness between Ni and Li-Pb affects the overall H{sub 2} permeation rate. When the flow velocity of Li-Pb increases, the thickness of the boundary layer becomes thin, and the driving force of H{sub 2} permeation through the Ni wall becomes bigger. (authors)

  1. Metals and metalloids in atmospheric dust: Use of lead isotopic analysis for source apportionment

    Science.gov (United States)

    Felix Villar, Omar I.

    Mining activities generate aerosol in a wide range of sizes. Smelting activities produce mainly fine particles ( 1 microm). The adverse effects of aerosols on human health depend mainly on two key characteristics: size and chemical composition. One of the main objectives of this research is to analyze the size distribution of contaminants in aerosol produced by mining operations. For this purpose, a Micro-Orifice Uniform Deposit Impactor (MOUDI) was utilized. Results from the MOUDI samples show higher concentrations of the toxic elements like lead and arsenic in the fine fraction (Mitigation strategies could be developed if the source of contamination is well defined. Environmental conditions as wind speed, wind direction, relative humidity and precipitation have an important role in the concentration of atmospheric dust. Dry environments with low relative humidity are ideal for the transport of aerosols. Results obtained from this research show the relationship between dust concentrations and meteorological parameters. Dust concentrations are highly correlated with relative humidity and wind speed. With all the data collected on site and the analysis of the meteorological parameters, models can be develop to predict the transport of particles as well as the concentration of contaminants at a specific point. These models were developed and are part of the results shown in this dissertation.

  2. The effects of CaNa(2)EDTA on brain lead mobilization in rodents determined using a stable lead isotope tracer.

    Science.gov (United States)

    Seaton, C L; Lasman, J; Smith, D R

    1999-09-15

    Studies have demonstrated the efficacy of CaNa(2)EDTA for reducing lead (Pb) levels in blood and soft tissues, including brain. However, a concern remains that a single dose of CaNa(2)EDTA may cause a significant increase in brain Pb levels due to a redistribution of endogenous Pb. Here we utilized a rodent model of Pb exposure in combination with a sensitive stable Pb isotope tracer methodology to assess the effects of CaNa(2)EDTA chelation treatment on the redistribution of Pb in brain, blood, kidney, and bone tissues. Thirty-two adult female albino rats (n = 6-7 animals/group) were exposed to 100 microg Pb/mL in drinking water for 4 weeks. Stable (204)Pb tracer was administered via i.p. injection over 2 days prior to chelation. CaNa(2)EDTA was administered i.p. at a dose of 150 mg/kg/day for 1 to 5 days. Statistical differences were evaluated with univariate ANOVA. Under the Pb exposure and chelation treatment regimens utilized here, there was no evidence of a measurable redistribution of endogenous Pb (as total Pb or labile (204)Pb tracer) into the brain after a single CaNa(2)EDTA dose. Further, CaNa(2)EDTA was not efficacious in measurably reducing brain or bone Pb levels, although brain levels of labile (204)Pb tracer were significantly reduced after 5 days of chelation. CaNa(2)EDTA treatment was effective in significantly reducing both blood and kidney Pb levels. Overall, these data substantiate the efficacy of CaNa(2)EDTA for reducing soft tissue Pb levels, but not total brain Pb, and they do not support concern for a transient increase in brain Pb levels with treatment. Copyright 1999 Academic Press.

  3. Thermal/structural analyses of several hydrogen-cooled leading-edge concepts for hypersonic flight vehicles

    Science.gov (United States)

    Gladden, Herbert J.; Melis, Matthew E.; Mockler, Theodore T.; Tong, Mike

    1990-01-01

    The aerodynamic heating at high flight Mach numbers, when shock interference heating is included, can be extremely high and can exceed the capability of most conventional metallic and potential ceramic materials available. Numerical analyses of the heat transfer and thermal stresses are performed on three actively cooled leading-edge geometries (models) made of three different materials to address the issue of survivability in a hostile environment. These analyses show a mixture of results from one configuration to the next. Results for each configuration are presented and discussed. Combinations of enhanced internal film coefficients and high material thermal conductivity of copper and tungsten are predicted to maintain the maximum wall temperature for each concept within acceptable operating limits. The exception is the TD nickel material which is predicted to melt for most cases. The wide range of internal impingement film coefficients (based on correlations) for these conditions can lead to a significant uncertainty in expected leading-edge wall temperatures. The equivalent plastic strain, inherent in each configuration which results from the high thermal gradients, indicates a need for further cyclic analysis to determine component life.

  4. Discerning crystal growth from diffusion profiles in zoned olivine by in situ Mg–Fe isotopic analyses

    Science.gov (United States)

    Sio, Corliss Kin I.; Dauphas, Nicolas; Teng, Fang-Zhen; Chaussidon, Marc; Helz, Rosalind T.; Roskosz, Mathieu

    2013-01-01

    Mineral zoning is used in diffusion-based geospeedometry to determine magmatic timescales. Progress in this field has been hampered by the challenge to discern mineral zoning produced by diffusion from concentration gradients inherited from crystal growth. A zoned olivine phenocryst from Kilauea Iki lava lake (Hawaii) was selected for this study to evaluate the potential of Mg and Fe isotopes for distinguishing these two processes. Microdrilling of the phenocryst (∼300 μm drill holes) followed by MC-ICPMS analysis of the powders revealed negatively coupled Mg and Fe isotopic fractionations (δ26Mg from +0.1‰ to −0.2‰ and δ56Fe from −1.2‰ to −0.2‰ from core to rim), which can only be explained by Mg–Fe exchange between melt and olivine. The data can be explained with ratios of diffusivities of Mg and Fe isotopes in olivine scaling as D2/D1 = (m1/m2)β with βMg ∼0.16 and βFe ∼0.27. LA-MC-ICPMS and MC-SIMS Fe isotopic measurements are developed and are demonstrated to yield accurate δ56Fe measurements within precisions of ∼0.2‰ (1 SD) at spatial resolutions of ∼50 μm. δ56Fe and δ26Mg stay constant with Fo# in the rim (late-stage overgrowth), whereas in the core (original phenocryst) δ56Fe steeply trends toward lighter compositions and δ26Mg trends toward heavier compositions with higher Fo#. A plot of δ56Fe vs. Fo# immediately distinguishes growth-controlled from diffusion-controlled zoning in these two regions. The results are consistent with the idea that large isotopic fractionation accompanies chemical diffusion in crystals, whereas fractional crystallization induces little or no isotopic fractionation. The cooling timescale inferred from the chemical-isotope zoning profiles is consistent with the documented cooling history of the lava lake. In the absence of geologic context, in situ stable isotopic measurements may now be used to interpret the nature of mineral zoning. Stable isotope measurements by LA-MC-ICPMS and MC

  5. Isotope Geochemistry of the Dongchuan Copper Deposit,Yunnan,SW China: Stratigraphic Chronology and Application of Lead Isotopes in Geochemical Exploration

    Institute of Scientific and Technical Information of China (English)

    常向阳; 朱炳泉

    2002-01-01

    In this paper the Pb-Pb isochron method was used to determine the isotopic ages of te Luoxue Formation dolomites(1716±56Ma),th Heishan Formation carbonaceous slated (1607±128Ma) of the middle sub-group of the Kunyang Group and the Dayingpan Formation carbonaceous slates(1258±Ma) of the upper sub-group of the Kunyang Group.The age of the middle sub-group of the Kunyang Group is about 1800-1600Ma,belonging to the Late Paleo-Proterozoic,and that of the Dayingpan Formation in the upper sub-group of the Kunyang Group is about 1200-1300Ma, belonging to the Middle Poroterozoic.In addition,the Pb isotope chemical exploration techniques were used to study systematically the Pb isotopic compositions of rocks and ores across the No.14 vein in the middle segment of the No.1 pit of the Tangdan copper deposit and the result showed that the Pb isotope V1 values are neatively correlated with the copper contents.In is the first trial to use the systematic section method to conduct Pb isotope chemical exploration.

  6. Isotope Geochemistry of the Dongchuan Copper Deposit, Yunnan, SW China:Stratigraphic Chronology and Application of Lead Isotopes in Geochemical Exploration

    Institute of Scientific and Technical Information of China (English)

    常向阳; 朱炳泉

    2002-01-01

    In this paper the Pb-Pb isochron method was used to determine the isotopic ages of the Luoxue Formation dolomites (1716 ± 56 Ma), the Heishan Formation carbonaceous slates(1607 ± 128 Ma) of the middle sub-group of the Kunyang Group and the Dayingpan Formation carbonaceous slates ( 1258 ± 70Ma) of the upper sub-group of the Kunyang Group. The age of the middle sub-group of the Kunyang Group is about 1800 - 1600 Ma, belonging to the Late Paleo-Proterozoic, and that of the Dayingpan Formation in the upper sub-group of the Kunyang Group is about 1200 - 1300 Ma, belonging to the Middle Proterozoic. In addition, the Pb isotope chemical exploration techniques were used to study systematically the Pb isotopic compositions of rocks and ores across the No. 14 vein in the middle segment of the No. 1 pit of the Tangdan copper deposit and the result showed that the Pb isotope V1 values are negatively correlated with the copper contents. It is the first trial to use the systematic section method to conduct Pb isotope chemical exploration.

  7. Determination of the urinary cortisol production rate using (1,2,3,4-13C)cortisol. Isotope dilution analyses at very small enrichments.

    Science.gov (United States)

    Chapman, T E; Kraan, G P; Drayer, N M; Nagel, G T; Wolthers, B G

    1987-02-01

    An isotope dilution mass spectrometric method to determine the urinary cortisol production rate (CPR) in babies and children is described. The method uses stable isotopically labelled (1,2,3,4-13C)cortisol. The tracer is intravenously administered to the patient and urine is collected for the following three days. Following extraction, enzymic hydrolysis, purification and isolation by high-performance liquid chromatography (HPLC) the urinary cortisol metabolites tetrahydrocortisone, tetrahydrocortisol, alpha- and beta-cortolone are separately oxidized the common product, 11-oxo-aetiocholanolone. The methyl oxime tert-butyldimethylsilyl ether derivative (MO TBDMS) was analysed by gas chromatography mass spectrometry. Quantification of the isotope enrichment was carried out by unlabelled, and at m/z 348 for labelled 11-oxo-aetiocholanolone. HPLC isolation of the metabolites together with the oxidation step allowed very small isotope enrichments, sometimes down to 0.1% (1:1000), to be reliably measured against a linear calibration graph containing 0 to 1% (13C4) enrichments. The standards for the calibration graph were synthesized from mixtures of labelled (13C4) cortisol and natural cortisol, and the calibration graph was prepared each time samples were measured. The long term instrumental precision of the isotope dilution analyses was 0.91% for a derivatized sample containing a (13C4) enrichment of 0.5% (measured on six different days over seven months). The coefficient of variation of the complete procedure for the four cortisol metabolites was between 1.17 and 2.14%. The clinical applicability of the method is demonstrated by presenting the results of a CPR determination in a patient.

  8. Coupling lead isotopes and element concentrations in epiphytic lichens to track sources of air emissions in the Alberta Oil Sands Region

    Science.gov (United States)

    A study was conducted that coupled use of element concentrations and lead (Pb) isotope ratios in the lichen Hypogymnia physodes collected during 2002 and 2008, to assess the impacts of air emissions from the Alberta Oil Sands Region (AOSR, Canada) mining and processing operations...

  9. Coupling lead isotopes and element concentrations in epiphytic lichens to track sources of air emissions in the Alberta Oil Sands Region

    Science.gov (United States)

    A study was conducted that coupled use of element concentrations and lead (Pb) isotope ratios in the lichen Hypogymnia physodes collected during 2002 and 2008, to assess the impacts of air emissions from the Alberta Oil Sands Region (AOSR, Canada) mining and processing operations...

  10. Micro-EDXRF surface analyses of a bronze spear head: Lead content in metal and corrosion layers

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, E. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Departamento de Conservacao e Restauro, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica (Portugal)], E-mail: elin@itn.pt; Valerio, P.; Araujo, M.F. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Senna-Martinez, J.C. [Instituto de Arqueologia, Faculdade de Letras da Universidade de Lisboa, Cidade Universitaria, Campo Grande, 1600-214 Lisbon (Portugal)

    2007-09-21

    A bronze spear head from Central Portugal dated to Late Bronze Age has been analyzed by non-destructive micro-EDXRF in the metal surface and corrosion layers. The artifact had previously been analyzed using a conventional EDXRF spectrometer having a larger incident beam. The quantification of the micro-EDXRF analyses showed that lead content in corrosion layers can reach values up to four times higher than the content determined in the metal surface. Results obtained with the higher energy incident beam from the EDXRF equipment, although referring mainly to the corrosion layers, seem to suffer some influence from the surface composition of the metallic alloy.

  11. Compound-specific amino acid isotopic analyses of invertebrates in the Chukchi Sea: New insights on food web dynamics

    Science.gov (United States)

    Zhang, M.; Cooper, L. W.; Biasatti, D. M.; Kedra, M.; Grebmeier, J. M.

    2016-02-01

    Food web dynamics in the Chukchi Sea have been previously evaluated using bulk analysis of stable carbon and nitrogen isotopes of organisms. However, recent advances in compound-specific stable isotope analysis of amino acids indicate the potential to better identify the contributions of different dietary sources (e.g., pelagic vs. benthic, ice algae vs. phytoplankton) and to resolve complexities of food web structure that are difficult to address with bulk isotope analysis. Here we combine amino acid δ13C and δ15N data measured from primary producers and tissues of bivalves, polychaetes and other benthic invertebrates collected during two cruises in the summer of 2013 and 2015 in the Pacific Arctic. The results showed spatial variation of carbon isotope values in amino acids with difference up to 6 per mil for each individual species or taxa studied, indicating a shift in the food-web baseline geographically. Furthermore, the spatial variation in isotopic values was related to environmental factors, specifically sea ice extent, and total organic carbon, total organic nitrogen and the carbon/nitrogen ratio of the organic fractions of surface sediments. Results also indicated that trophic levels, as estimated by differences in the nitrogen isotope composition of glutamic acid and phenylalanine [Δ15Nglu-phe (δ15Nglu - δ15Nphe)], varied spatially by 0.5 to 1.5 trophic levels for certain species or taxa such as Macoma calcarea, Maldanidae and Ampelisca, indicating trophic level shifts that were associated with the food quality of organic matter in the organic fraction of the sediments. These results can be potentially used to predict future food web change in this high latitude marine system that is known for its ecological importance and on-going environmental changes, including warming and sea ice decline.

  12. Lead isotope exchange between dissolved and fluvial particulate matter: a laboratory study from the Johor River estuary

    Science.gov (United States)

    Chen, Mengli; Boyle, Edward A.; Lee, Jong-Mi; Nurhati, Intan; Zurbrick, Cheryl; Switzer, Adam D.; Carrasco, Gonzalo

    2016-11-01

    Atmospheric aerosols are the dominant source of Pb to the modern marine environment, and as a result, in most regions of the ocean the Pb isotopic composition of dissolved Pb in the surface ocean (and in corals) matches that of the regional aerosols. In the Singapore Strait, however, there is a large offset between seawater dissolved and coral Pb isotopes and that of the regional aerosols. We propose that this difference results from isotope exchange between dissolved Pb supplied by anthropogenic aerosol deposition and adsorbed natural crustal Pb on weathered particles delivered to the ocean by coastal rivers. To investigate this issue, Pb isotope exchange was assessed through a closed-system exchange experiment using estuarine waters collected at the Johor River mouth (which discharges to the Singapore Strait). During the experiment, a known amount of dissolved Pb with the isotopic composition of NBS-981 (206Pb/207Pb = 1.093) was spiked into the unfiltered Johor water (dissolved and particulate 206Pb/207Pb = 1.199) and the changing isotopic composition of the dissolved Pb was monitored. The mixing ratio of the estuarine and spike Pb should have produced a dissolved 206Pb/207Pb isotopic composition of 1.161, but within a week, the 206Pb/207Pb in the water increased to 1.190 and continued to increase to 1.197 during the next two months without significant changes of the dissolved Pb concentration. The kinetics of isotope exchange was assessed using a simple Kd model, which assumes multiple sub-reservoirs within the particulate matter with different exchange rate constants. The Kd model reproduced 56% of the observed Pb isotope variance. Both the closed-system experiment and field measurements imply that isotope exchange can be an important mechanism for controlling Pb and Pb isotopes in coastal waters. A similar process may occur for other trace elements. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  13. Isotopic signatures suggest important contributions from recycled gasoline, road dust and non-exhaust traffic sources for copper, zinc and lead in PM10 in London, United Kingdom

    Science.gov (United States)

    Dong, Shuofei; Ochoa Gonzalez, Raquel; Harrison, Roy M.; Green, David; North, Robin; Fowler, Geoff; Weiss, Dominik

    2017-09-01

    The aim of this study was to improve our understanding of what controls the isotope composition of Cu, Zn and Pb in particulate matter (PM) in the urban environment and to develop these isotope systems as possible source tracers. To this end, isotope ratios (Cu, Zn and Pb) and trace element concentrations (Fe, Al, Cu, Zn, Sb, Ba, Pb, Cr, Ni and V) were determined in PM10 collected at two road sites with contrasting traffic densities in central London, UK, during two weeks in summer 2010, and in potential sources, including non-combustion traffic emissions (tires and brakes), road furniture (road paint, manhole cover and road tarmac surface) and road dust. Iron, Ba and Sb were used as proxies for emissions derived from brake pads, and Ni, and V for emissions derived from fossil fuel oil. The isotopic composition of Pb (expressed using 206Pb/207Pb) ranged between 1.1137 and 1.1364. The isotope ratios of Cu and Zn expressed as δ65CuNIST976 and δ66ZnLyon ranged between -0.01‰ and +0.51‰ and between -0.21‰ and +0.33‰, respectively. We did not find significant differences in the isotope signatures in PM10 over the two weeks sampling period and between the two sites, suggesting similar sources for each metal at both sites despite their different traffic densities. The stable isotope composition of Pb suggests significant contribution from road dust resuspension and from recycled leaded gasoline. The Cu and Zn isotope signatures of tires, brakes and road dust overlap with those of PM10. The correlation between the enrichments of Sb, Cu, Ba and Fe in PM10 support the previously established hypothesis that Cu isotope ratios are controlled by non-exhaust traffic emission sources in urban environments (Ochoa Gonzalez et al., 2016). Analysis of the Zn isotope signatures in PM10 and possible sources at the two sites suggests significant contribution from tire wear. However, temporary additional sources, likely high temperature industrial emissions, need to be invoked

  14. Lead isotopic compositions of soil and near-surface till profiles from a watershed containing arsenic-enriched groundwater in coastal Maine

    Science.gov (United States)

    Ayuso, Robert; Foley, Nora; Wandless, Gregory; Dillingham, Jeremy; Colvin, Anna

    2005-01-01

    Lead isotope compositions of soils and near-surface tills from an area of coastal Maine known to have groundwater with anomalously high arsenic contents were measured in order to determine the source of the lead and, by inference, possible sources of arsenic. Five soil and till sites were selected for detailed chemical and isotopic analysis. To construct profiles of the soil and till horizons, five samples were collected at 10-cm intervals from the surface to the base of each horizon. Total lead and arsenic concentrations and lead isotopic compositions were measured for 48 leaches and bulk residues. The soils and tills are underlain by sulfidic schists of the Penobscot Formation. Several generations of minerals containing arsenic and lead exist in the regional bedrock, including rock-forming silicates (feldspar and micas), sulfide minerals formed during diagenesis (for example, arsenic-rich pyrite), and sulfide and oxide minerals that formed as a result of Silurian metamorphic and igneous events (for example, arsenopyrite, galena, iron-oxides, and arsenic-sulfides). A young group of secondary minerals (for example, iron-hydroxides, arsenic-hydroxides, lead-sulfate, and arsenic-jarosite) formed from recent weathering and pedogenic processes.

  15. Multivariate spatial analyses of the distribution and origin of trace and major elements in soils surrounding a secondary lead smelter.

    Science.gov (United States)

    Schneider, Arnaud R; Morvan, Xavier; Saby, Nicolas P A; Cancès, Benjamin; Ponthieu, Marie; Gommeaux, Maxime; Marin, Béatrice

    2016-08-01

    Major and trace elements in soils originate from natural processes and different anthropogenic activities which are difficult to discriminate. On a 17-ha impacted site in northern France, two industrial sources of soil contamination were xidentified: a former iron foundry and a current secondary lead smelter. To discriminate and map natural and anthropogenic sources of major and trace elements on this site, the rarely applied MULTISPATI-principal component analysis (PCA) method was used. Using a 20-m × 20-m grid, 247 topsoil horizons were sampled and analysed with a field-portable X-ray fluorescence analyser for screening soil contamination. The study site was heavily contaminated with Pb and, to a lesser degree, with Sn. Summary statistics and enrichment factors allowed the differentiation of the main lithogenic or anthropogenic origin of the elements. The MULTISPATI-PCA method, which explained 73.9 % of the variability with the three first factors, evidenced strong spatial structures. Those spatial structures were attributed to different natural and artificial processes in the study area. The first axis can be interpreted as a lithogenic effect. Axes 2 and 3 reflect the two different contamination sources. Pb, Sn and S originated from the secondary lead smelter while Fe and Ca were mainly derived from the old iron foundry activity and the old railway built with foundry sand. This study demonstrated that the MULTISPATI-PCA method can be successfully used to investigate multicontaminated sites to discriminate the various sources of contamination.

  16. Hydrogen isotope correction for laser instrument measurement bias at low water vapor concentration using conventional isotope analyses: application to measurements from Mauna Loa Observatory, Hawaii.

    Science.gov (United States)

    Johnson, L R; Sharp, Z D; Galewsky, J; Strong, M; Van Pelt, A D; Dong, F; Noone, D

    2011-03-15

    The hydrogen and oxygen isotope ratios of water vapor can be measured with commercially available laser spectroscopy analyzers in real time. Operation of the laser systems in relatively dry air is difficult because measurements are non-linear as a function of humidity at low water concentrations. Here we use field-based sampling coupled with traditional mass spectrometry techniques for assessing linearity and calibrating laser spectroscopy systems at low water vapor concentrations. Air samples are collected in an evacuated 2 L glass flask and the water is separated from the non-condensable gases cryogenically. Approximately 2 µL of water are reduced to H(2) gas and measured on an isotope ratio mass spectrometer. In a field experiment at the Mauna Loa Observatory (MLO), we ran Picarro and Los Gatos Research (LGR) laser analyzers for a period of 25 days in addition to periodic sample collection in evacuated flasks. When the two laser systems are corrected to the flask data, they are strongly coincident over the entire 25 days. The δ(2)H values were found to change by over 200‰ over 2.5 min as the boundary layer elevation changed relative to MLO. The δ(2)H values ranged from -106 to -332‰, and the δ(18)O values (uncorrected) ranged from -12 to -50‰. Raw data from laser analyzers in environments with low water vapor concentrations can be normalized to the international V-SMOW scale by calibration to the flask data measured conventionally. Bias correction is especially critical for the accurate determination of deuterium excess in dry air.

  17. An assessment of geochemical preparation methods prior to organic carbon concentration and carbon isotope ratio analyses of fine-grained sedimentary rocks

    Science.gov (United States)

    KöNitzer, Sven F.; Leng, Melanie J.; Davies, Sarah J.; Stephenson, Michael H.

    2012-09-01

    This study summarizes organic carbon isotope (δ13C) and total organic carbon (TOC) data from a series of tests undertaken to provide an appropriate methodology for pre-analysis treatment of mudstones from an Upper Carboniferous sedimentary succession, in order to develop a consistent preparation procedure. The main treatments involved removing both inorganic carbonate and hydrocarbons (which might be extraneous) before δ13C and TOC analysis. The results show that decarbonating using hydrochloric acid causes significant reduction in δ13C and total carbon (TC) of the bulk material due to the removal of inorganic carbonate. These changes are most pronounced where soluble calcium carbonate (rather than Ca-Mg-Fe carbonate) is present. Deoiled samples show only slightly higher mean δ13C where visible bitumen was extracted from the bulk sample. Moreover, the isotopic signatures of the extracts are closely correlated to those of their respective bulk samples, suggesting that small yields of hydrocarbons were generated in situ with no isotopic fractionation. In addition, further δ13C and TC analyses were performed on samples where mixing of oil-based drilling mud with brecciated core material had been undertaken. Brecciated mudstone material did not display distinct isotopic signals compared to the surrounding fine-grained material. Overall we show that the most accurate assessment of bulk organic carbon isotopes and concentration in these samples can be achieved through decarbonating the material prior to measurement via the `rinse method'. However, our results support recent findings that pre-analysis acid treatments can cause variable and unpredictable errors in δ13C and TOC values. We believe that, despite these uncertainties, the findings presented here can be applied to paleoenvironmental studies on organic matter contained within sedimentary rocks over a range of geological ages and compositions.

  18. Lead isotopic signatures in Antarctic marine sediment cores: a comparison between 1M HCl partial extraction and HF total digestion pre-treatments for discerning anthropogenic inputs.

    Science.gov (United States)

    Townsend, A T; Snape, I; Palmer, A S; Seen, A J

    2009-12-20

    Sensitive analytical techniques are typically required when dealing with samples from Antarctica as even low concentrations of contaminants can have detrimental environmental effects. Magnetic Sector ICP-MS is an ideal technique for environmental assessment as it offers high sensitivity, multi-element capability and the opportunity to determine isotope ratios. Here we consider the Pb isotope record of five marine sediment cores collected from three sites in the Windmill Islands area of East Antarctica: Brown Bay adjacent to the current Australian station Casey, Wilkes near the abandoned US/Australian Station and McGrady Cove lying midway between the two. Two sediment pre-treatment approaches were considered, namely partial extraction with 1M HCl and total dissolution involving HF. Lead isotope ratio measurements made following sediment partial extraction provided a more sensitive indication of Pb contamination than either Pb concentrations alone (irrespective of sample pre-treatment method) or isotope ratios made after HF digestion, offering greater opportunity for discrimination between impacted and natural/geogenic samples and sites. Over 90% of the easily extractable Pb from sediments near Casey was anthropogenic in origin, consisting of Pb from major Australian deposits. At Wilkes impact from discarded batteries with a unique isotopic signature was found to be a key source of Pb contamination to the marine environment with ~70-80% of Pb being anthropogenic in origin. The country and source of origin of these batteries remain unknown. Little evidence was found suggesting contamination at Wilkes by Pb originating from the major US source, Missouri. No definitive assessment could be made regarding Pb impact at McGrady Cove as the collected sediment core was of insufficient depth. Although Pb isotope ratio signatures may indicate anthropogenic input, spatial concentration gradients at nearby Brown Bay suggest contamination at McGrady Cove is unlikely. We recommend

  19. Paleoenvironmental conditions and strontium isotope stratigraphy in the Paleogene Gafsa Basin (Tunisia) deduced from geochemical analyses of phosphatic fossils

    Science.gov (United States)

    Kocsis, László; Ounis, Anouar; Chaabani, Fredj; Salah, Neili Mohamed

    2013-06-01

    Fossil shark teeth and coprolites from three major phosphorite occurrences in the Gafsa Basin (southwestern Tunisia) were investigated for their geochemical compositions to improve local stratigraphy and to better assess paleoenvironmental conditions. 87Sr/86Sr isotope ratios of shark teeth from the Early Maastrichtian El Haria Formation and from the Early Eocene Métlaoui s.s. Formation yielded Sr isotope ages of 68 ± 1 and 47.9 ± 1.3 Ma, respectively, which accord with the expected stratigraphic positions of these sediments. Conversely, shark teeth from the Paleocene-Eocene Chouabine Formation have large variation in Sr isotope ratios even within individual layers. After statistical treatment and then elimination of certain outlier samples, three age-models are proposed and discussed. The most reasonable solution includes three subsequent Sr ages of 61.8 ± 2.2 Ma, 57.2 ± 1.8 and 54.6 ± 1.6 for layer IX, layers VIII-V and layers IV-0, respectively. Three scenarios are discussed for explanation of the presence of the outliers: (1) diagenesis, (2) re-working and (3) locally controlled seawater Sr isotope ratio. The most plausible account for the higher 87Sr/86Sr ratios relative to the global ocean in some fossils is enhanced intrabasinal re-working due to low sea level. Conversely, the sample with lower 87Sr/86Sr than the global seawater may link to diagenesis or to seawater influenced by weathering of Late Cretaceous marine carbonates, which latter is supported by model calculation as well. The ɛNd values of these fossils are very similar to those reported for Paleogene and Late Cretaceous Tethyan seawater and are compatible with the above interpretations. The relatively low oxygen isotope values in shark teeth from the topmost phosphate bed of the Chouabine Formation, together with the Sr isotope results, point toward recovering better connections with the open sea. These δ18O data reflect elevated ambient temperature, which may link to the Early Eocene

  20. Total lead (Pb) concentration in oil shale ash samples based on correlation to isotope Pb-210 gamma-spectrometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Vaasma, T.; Kiisk, M.; Tkaczyk, A.H. [University of Tartu (Estonia); Bitjukova, L. [Tallinn University of Technology (Estonia)

    2014-07-01

    (PF) and circulating fluidized bed (CFB) firing technology. These samples were analyzed to determine macro and trace elements by the ICP-MS method. The same samples were also measured with a high-purity germanium detector (planar BSI GPD-50400) to determine the activity concentrations of natural radionuclides. The lead concentrations and Pb-210 activity concentrations were determined, and the correlation between the corresponding values was analyzed. Initial results demonstrate a strong positive linear relationship between these values, with the coefficient of determination (R{sup 2}) over 94. The correlation coefficient (Pearson's, 'r') had a value over 0.95. Both Pb and Pb-210 values had an increasing trend from the bottom ash towards electrostatic precipitator (ESP) ashes. The strong linear correlation between Pb concentrations and Pb-210 activity concentrations gives a credible indication that lead can be measured in ash samples using its radioactive isotope Pb-210. Especially in situations where there are higher concentrations of Pb, for example in the case of wastes from the metallurgic and energy industries, this method could be used to detect the lead concentration quickly and with no chemical processing of the sample. Document available in abstract form only. (authors)

  1. Lead isotopic composition of trinitite melt glass: evidence for the presence of Canadian industrial lead in the first atomic weapon test.

    Science.gov (United States)

    Bellucci, Jeremy J; Simonetti, Antonio; Wallace, Christine; Koeman, Elizabeth C; Burns, Peter C

    2013-08-06

    The Pb isotopic compositions for 51 spots of melt glass in 11 samples of trinitite have been determined by laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). Trinitite glass yields a large range of Pb isotopic compositions (i.e., (206)Pb/(204)Pb = 17.08-19.04), which reflect mixing between industrial Pb from materials used in the Trinity test and natural geologic components. Areas within trinitite melt glass containing high concentrations of both Cu and Pb, which are derived from the bomb and blast site-related components, were used for delineating the Pb isotopic composition corresponding to the anthropogenic Pb component. Comparison between the isotopic composition estimated here for the industrial Pb used in the Trinity test and those from known Pb deposits worldwide indicates close agreement with ore from the Buchans mine (Newfoundland, Canada). The Buchans mine was active during the time of the Trinity test and was operated by the American Smelting and Refining Company, which could have provided the Pb used in the test. The industrial Pb used in the Trinity test materials is not documented in the literature (or declassified) but could have been present in bricks, solder, pigs, or some other anthropogenic component related to the experiment.

  2. Point processes statistics of stable isotopes: analysing water uptake patterns in a mixed stand of Aleppo pine and Holm oak

    OpenAIRE

    Carles Comas; Jorge del Castillo,; Jordi Voltas; Juan Pedro Ferrio

    2015-01-01

    Aim of study: Understanding inter- and intra-specific competition for water is crucial in drought-prone environments. However, little is known about the spatial interdependencies for water uptake among individuals in mixed stands. The aim of this work was to compare water uptake patterns during a drought episode in two common Mediterranean tree species, Quercus ilex L. and Pinus halepensis Mill., using the isotope composition of xylem water (δ18O, δ2 H) as hydrological marker. ...

  3. Authentication of farmed and wild turbot (Psetta maxima) by fatty acid and isotopic analyses combined with chemometrics.

    Science.gov (United States)

    Busetto, Maria L; Moretti, Vittorio M; Moreno-Rojas, Jose M; Caprino, Fabio; Giani, Ivan; Malandra, Renato; Bellagamba, Federica; Guillou, Claude

    2008-04-23

    Fatty acid composition and stable isotope ratios of carbon (delta(13)C) and nitrogen (delta(15)N) were determined in muscle tissue of turbot (Psetta maxima). The multivariate analysis of the data was performed to evaluate their utility in discriminating wild and farmed fish. Wild (n=30) and farmed (n=30) turbot of different geographical origins (Denmark, The Netherlands, and Spain) were sampled from March 2006 to February 2007. The application of linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA) to analytical data demonstrated the combination of fatty acids and isotopic measurements to be a promising method to discriminate between wild and farmed fish and between wild fish of different geographical origin. In particular, IRMS (Isotope Ratio Mass Spectrometry) alone did not permit us to separate completely farmed from wild samples, resulting in some overlaps between Danish wild and Spanish farmed turbot. On the other hand, fatty acids alone differentiated between farmed and wild samples by 18:2n-6 but were not able to distinguish between the two groups of wild turbot. When applying LDA isotope ratios, 18:2n-6, 18:3n-3, and 20:4n-6 fatty acids were decisive to distinguish farmed from wild turbot of different geographical origin, while delta(15)N, 18:2n-6, and 20:1n-11 were chosen to classify wild samples from different fishing zones. In both cases, 18:2n-6 and delta(15)N were determinant for classification purposes. We would like to emphasize that IRMS produces rapid results and could be the most promising technique to distinguish wild fish of different origin. Similarly, fatty acid composition could be used to easily distinguish farmed from wild samples.

  4. Tracking the metabolic pulse of plant lipid production with isotopic labeling and flux analyses: Past, present and future.

    Science.gov (United States)

    Allen, Doug K; Bates, Philip D; Tjellström, Henrik

    2015-04-01

    Metabolism is comprised of networks of chemical transformations, organized into integrated biochemical pathways that are the basis of cellular operation, and function to sustain life. Metabolism, and thus life, is not static. The rate of metabolites transitioning through biochemical pathways (i.e., flux) determines cellular phenotypes, and is constantly changing in response to genetic or environmental perturbations. Each change evokes a response in metabolic pathway flow, and the quantification of fluxes under varied conditions helps to elucidate major and minor routes, and regulatory aspects of metabolism. To measure fluxes requires experimental methods that assess the movements and transformations of metabolites without creating artifacts. Isotopic labeling fills this role and is a long-standing experimental approach to identify pathways and quantify their metabolic relevance in different tissues or under different conditions. The application of labeling techniques to plant science is however far from reaching it potential. In light of advances in genetics and molecular biology that provide a means to alter metabolism, and given recent improvements in instrumentation, computational tools and available isotopes, the use of isotopic labeling to probe metabolism is becoming more and more powerful. We review the principal analytical methods for isotopic labeling with a focus on seminal studies of pathways and fluxes in lipid metabolism and carbon partitioning through central metabolism. Central carbon metabolic steps are directly linked to lipid production by serving to generate the precursors for fatty acid biosynthesis and lipid assembly. Additionally some of the ideas for labeling techniques that may be most applicable for lipid metabolism in the future were originally developed to investigate other aspects of central metabolism. We conclude by describing recent advances that will play an important future role in quantifying flux and metabolic operation in plant

  5. Lead isotope distribution in podzolic soil profiles on different types of bedrock in a formerly glaciated terrain (Oslo, Norway)

    Energy Technology Data Exchange (ETDEWEB)

    Saether, O.M., E-mail: ola.sather@ngu.no [Geological Survey of Norway, Leiv Eirikssons vei 39, NO-7094 Trondheim (Norway); Aberg, G. [Laboratory for Isotope Geology, Box 50007, SE-104 05 Stockholm (Sweden); Steinnes, E. [Department of Chemistry, NTNU, NO-7491 Trondheim (Norway)

    2011-06-15

    Highlights: > Four sites with different lithology (syenite, gneiss, granite, sedimentary rocks), formerly glaciated terrain, Oslo, Norway. > Variations with depth of grain-size, total organic C, Pb concentration, Pb isotope ratio. > Content of anthropogenic Pb in podzolic forest soil. > Comparison of three methods for calculating anthropogenic Pb input. > Amounts of anthropogenic Pb in upper 20 cm calculated to be 1-6 t/km{sup 2}. - Abstract: Lead has been exploited by man over thousands of years for a variety of metallurgical, medicinal, and industrial purposes. The cumulative output of Pb from mining is estimated to be 260 million metric tonnes and 85% of this has occurred over the last two centuries. Global annual production of Pb from mining was about 3 million tonnes at the turn of the millenium. Terrestrial ecosystems all over Norway have been contaminated moderately to strongly by Pb and other trace elements from atmospheric deposition. With the aim of developing a method for mapping the accumulated content of anthropogenic Pb and how deep in the soil profile the atmospherically deposited Pb has penetrated, the concentration of Pb and the {sup 206}Pb/{sup 207}Pb ratio has been studied in podzolic forest soils at four locations with different lithology, i.e. age and type of bedrock, in the Oslo area. The concentrations of Pb in the soil profiles are 6.6-38.1 mg/kg (median 10.3). The {sup 206}Pb/{sup 207}Pb ratio ranges between 1.168 and 1.314 (median 1.267) over the entire profile. In the upper 5 cm the range is 1.168-1.191, similar to ratios determined in recent atmospheric deposition. Applying three different methods, the amount of anthropogenically deposited Pb is estimated at 1-6 t/km{sup 2}.

  6. The traceability of animal meals in layer diets as detected by stable carbon and nitrogen isotope analyses of eggs

    Directory of Open Access Journals (Sweden)

    JC Denadai

    2008-09-01

    Full Text Available The aim of this study was to trace the inclusion of animal meals in layer diets by analyzing eggs and their fractions (yolk and albumen using the technique of carbon and nitrogen isotopes. Two-hundred and eighty-eight (288 73-week-old Shaver White layers, never fed animal ingredients, were randomly distributed in six treatments with six replicates each. The treatments were: control - corn and soybean meal based diet and five other experimental diets including bovine meat and bone meal (MBM; poultry offal meal (POM; feather meal (FM; feather meal and poultry offal meal (OFM, and poultry offal meal, feather meal, and meat and bone meal (MBOFM. The isotopic results were submitted to multivariate analysis of variance. Ellipses were determined through an error matrix (95% confidence to identify differences between treatments and the control group. In the albumen and yolk of all experimental treatments were significantly different from the control diet (p < 0.05. In summary, the stable isotope technique is able to trace the animal meals included in layer feeds in the final product under these experimental conditions.

  7. Fingerprints for main varieties of argentinean wines: terroir differentiation by inorganic, organic, and stable isotopic analyses coupled to chemometrics.

    Science.gov (United States)

    Di Paola-Naranjo, Romina D; Baroni, Maria V; Podio, Natalia S; Rubinstein, Hector R; Fabani, Maria P; Badini, Raul G; Inga, Marcela; Ostera, Hector A; Cagnoni, Mariana; Gallegos, Ernesto; Gautier, Eduardo; Peral-Garcia, Pilar; Hoogewerff, Jurian; Wunderlin, Daniel A

    2011-07-27

    Our main goal was to investigate if robust chemical fingerprints could be developed for three Argentinean red wines based on organic, inorganic, and isotopic patterns, in relation to the regional soil composition. Soils and wines from three regions (Mendoza, San Juan, and Córdoba) and three varieties (Cabernet Sauvignon, Malbec, and Syrah) were collected. The phenolic profile was determined by HPLC-MS/MS and multielemental composition by ICP-MS; (87)Sr/(86)Sr and δ(13)C were determined by TIMS and IRMS, respectively. Chemometrics allowed robust differentiation between regions, wine varieties, and the same variety from different regions. Among phenolic compounds, resveratrol concentration was the most useful marker for wine differentiation, whereas Mg, K/Rb, Ca/Sr, and (87)Sr/(86)Sr were the main inorganic and isotopic parameters selected. Generalized Procrustes analysis (GPA) using two studied matrices (wine and soil) shows consensus between them and clear differences between studied areas. Finally, we applied a canonical correlation analysis, demonstrating significant correlation (r = 0.99; p soil and wine composition. To our knowledge this is the first report combining independent variables, constructing a fingerprint including elemental composition, isotopic, and polyphenol patterns to differentiate wines, matching part of this fingerprint with the soil provenance.

  8. 我国城市大气颗粒物的铅同位素丰度比%Lead Isotope Abundance Ratios of Urban Atmospheric Aerosols in China

    Institute of Scientific and Technical Information of China (English)

    刘咸德; 李显芳; 李冰

    2004-01-01

    Determined with ICP-MS, new isotope abundance ratio data of lead for Beijing and Changdao aerosols was presented, in comparison with literature data for Chinese urban aerosols. 206Pb/207Pb ratio falls into a range from 1.13 to 1.18 for urban aerosols and less influenced by vehicle exhaust emission after phase-out of leaded petrol in 2000 in China. Major lead pollution sources may probably include coal combustion, oil combustion,re-suspended dust, metallurgical industry and use and production of cement.

  9. Testing the limits of micro-scale analyses of Si stable isotopes by femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry with application to rock weathering

    Energy Technology Data Exchange (ETDEWEB)

    Schuessler, Jan A., E-mail: jan.schuessler@gfz-potsdam.de; Blanckenburg, Friedhelm von

    2014-08-01

    An analytical protocol for accurate in-situ Si stable isotope analysis has been established on a new second-generation custom-built femtosecond laser ablation system. The laser was coupled to a multicollector inductively coupled plasma mass spectrometer (fsLA-MC-ICP-MS). We investigated the influence of laser parameters such as spot size, laser focussing, energy density and repetition rate, and ICP-MS operating conditions such as ICP mass load, spectral and non-spectral matrix effects, signal intensities, and data processing on precision and accuracy of Si isotope ratios. We found that stable and reproducible ICP conditions were obtained by using He as aerosol carrier gas mixed with Ar/H{sub 2}O before entering the plasma. Precise δ{sup 29}Si and δ{sup 30}Si values (better than ± 0.23‰, 2SD) can be obtained if the area ablated is at least 50 × 50 μm; or, alternatively, for the analysis of geometric features down to the width of the laser spot (about 20 μm) if an equivalent area is covered. Larger areas can be analysed by rastering the laser beam, whereas small single spot analyses reduce the attainable precision of δ{sup 30}Si to ca. ± 0.6‰, 2SD, for < 30 μm diameter spots. It was found that focussing the laser beam beneath the sample surface with energy densities between 1 and 3.8 J/cm{sup 2} yields optimal analytical conditions for all materials investigated here. Using pure quartz (NIST 8546 aka. NBS-28) as measurement standard for calibration (standard-sample-bracketing) did result in accurate and precise data of international reference materials and samples covering a wide range in chemical compositions (Si single crystal IRMM-017, basaltic glasses KL2-G, BHVO-2G and BHVO-2, andesitic glass ML3B-G, rhyolitic glass ATHO-G, diopside glass JER, soda-lime glasses NIST SRM 612 and 610, San Carlos olivine). No composition-dependent matrix effect was discernible within uncertainties of the method. The method was applied to investigate the Si isotope

  10. Preliminary study to characterize plastic polymers using elemental analyser/isotope ratio mass spectrometry (EA/IRMS).

    Science.gov (United States)

    Berto, Daniela; Rampazzo, Federico; Gion, Claudia; Noventa, Seta; Ronchi, Francesca; Traldi, Umberto; Giorgi, Giordano; Cicero, Anna Maria; Giovanardi, Otello

    2017-06-01

    Plastic waste is a growing global environmental problem, particularly in the marine ecosystems, in consideration of its persistence. The monitoring of the plastic waste has become a global issue, as reported by several surveillance guidelines proposed by Regional Sea Conventions (OSPAR, UNEP) and appointed by the EU Marine Strategy Framework Directive. Policy responses to plastic waste vary at many levels, ranging from beach clean-up to bans on the commercialization of plastic bags and to Regional Plans for waste management and recycling. Moreover, in recent years, the production of plant-derived biodegradable plastic polymers has assumed increasing importance. This study reports the first preliminary characterization of carbon stable isotopes (δ(13)C) of different plastic polymers (petroleum- and plant-derived) in order to increase the dataset of isotopic values as a tool for further investigation in different fields of polymers research as well as in the marine environment surveillance. The δ(13)C values determined in different packaging for food uses reflect the plant origin of "BIO" materials, whereas the recycled plastic materials displayed a δ(13)C signatures between plant- and petroleum-derived polymers source. In a preliminary estimation, the different colours of plastic did not affect the variability of δ(13)C values, whereas the abiotic and biotic degradation processes that occurred in the plastic materials collected on beaches and in seawater, showed less negative δ(13)C values. A preliminary experimental field test confirmed these results. The advantages offered by isotope ratio mass spectrometry with respect to other analytical methods used to characterize the composition of plastic polymers are: high sensitivity, small amount of material required, rapidity of analysis, low cost and no limitation in black/dark samples compared with spectroscopic analysis.

  11. Late neogene and early quaternary paleoenvironmental and paleoclimatic conditions in southwestern Europe: isotopic analyses on mammalian taxa.

    Science.gov (United States)

    Domingo, Laura; Koch, Paul L; Hernández Fernández, Manuel; Fox, David L; Domingo, M Soledad; Alberdi, María Teresa

    2013-01-01

    Climatic and environmental shifts have had profound impacts on faunal and floral assemblages globally since the end of the Miocene. We explore the regional expression of these fluctuations in southwestern Europe by constructing long-term records (from ~11.1 to 0.8 Ma, late Miocene-middle Pleistocene) of carbon and oxygen isotope variations in tooth enamel of different large herbivorous mammals from Spain. Isotopic differences among taxa illuminate differences in ecological niches. The δ(13)C values (relative to VPDB, mean -10.3 ± 1.1‰; range -13.0 to -7.4‰) are consistent with consumption of C3 vegetation; C4 plants did not contribute significantly to the diets of the selected taxa. When averaged by time interval to examine secular trends, δ(13)C values increase at ~9.5 Ma (MN9-MN10), probably related to the Middle Vallesian Crisis when there was a replacement of vegetation adapted to more humid conditions by vegetation adapted to drier and more seasonal conditions, and resulting in the disappearance of forested mammalian fauna. The mean δ(13)C value drops significantly at ~4.2-3.7 Ma (MN14-MN15) during the Pliocene Warm Period, which brought more humid conditions to Europe, and returns to higher δ(13)C values from ~2.6 Ma onwards (MN16), most likely reflecting more arid conditions as a consequence of the onset of the Northern Hemisphere glaciation. The most notable feature in oxygen isotope records (and mean annual temperature reconstructed from these records) is a gradual drop between MN13 and the middle Pleistocene (~6.3-0.8 Ma) most likely due to cooling associated with Northern Hemisphere glaciation.

  12. Late neogene and early quaternary paleoenvironmental and paleoclimatic conditions in southwestern Europe: isotopic analyses on mammalian taxa.

    Directory of Open Access Journals (Sweden)

    Laura Domingo

    Full Text Available Climatic and environmental shifts have had profound impacts on faunal and floral assemblages globally since the end of the Miocene. We explore the regional expression of these fluctuations in southwestern Europe by constructing long-term records (from ~11.1 to 0.8 Ma, late Miocene-middle Pleistocene of carbon and oxygen isotope variations in tooth enamel of different large herbivorous mammals from Spain. Isotopic differences among taxa illuminate differences in ecological niches. The δ(13C values (relative to VPDB, mean -10.3 ± 1.1‰; range -13.0 to -7.4‰ are consistent with consumption of C3 vegetation; C4 plants did not contribute significantly to the diets of the selected taxa. When averaged by time interval to examine secular trends, δ(13C values increase at ~9.5 Ma (MN9-MN10, probably related to the Middle Vallesian Crisis when there was a replacement of vegetation adapted to more humid conditions by vegetation adapted to drier and more seasonal conditions, and resulting in the disappearance of forested mammalian fauna. The mean δ(13C value drops significantly at ~4.2-3.7 Ma (MN14-MN15 during the Pliocene Warm Period, which brought more humid conditions to Europe, and returns to higher δ(13C values from ~2.6 Ma onwards (MN16, most likely reflecting more arid conditions as a consequence of the onset of the Northern Hemisphere glaciation. The most notable feature in oxygen isotope records (and mean annual temperature reconstructed from these records is a gradual drop between MN13 and the middle Pleistocene (~6.3-0.8 Ma most likely due to cooling associated with Northern Hemisphere glaciation.

  13. Isotopic and chemical analyses of a temperate firn core from a Chinese alpine glacier and its regional climatic significance

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Mt. Yulong is the southernmost currently glacier-covered area in Eurasia, including China. There are 19 sub-tropical temperate glaciers on the mountain, controlled by the south-western monsoon climate. In the summer of 1999, a firn core, 10. 10 m long, extending down to glacier ice, was recovered in the accumulation area of the largest glacier, Baishui No. 1. Periodic variations of climatic signals above 7. 8 m depth were apparent, and net accumulation of four years was identified by the annual oscillations of isotopic and ionic composition. The boundaries of annual accumulation were confirmed by higher values of electrical conductivity and pH, and by dirty refreezing ice layers at the levels of summer surfaces. Calculated mean annual net accumulation from 1994/1995 to 1997/1998 was about 900 mm water equivalent. The amplitude of isotopic variations in the profile decreased with increasing depth, and isotopic homogenization occurred below 7. 8 m as a result of meltwater percolation. Variations of δ18O above 7. 8 m showed an approximate correlation with the winter climatic trend at Li Jiang Station, 25 km away. Concentrations of Ca2+ and Mg2+ were much higher than those of Na+ and K+ , indicating that the air masses for precipitation were mainly from a continental source, and that the core material accumulated during the winter period. The close correspondence of C1- and Na+ indicated their common origin. Very low concentrations of SO2-4 and NO3- suggest that pollution caused by human activities is quite low in the area. The mean annual net accumulation in the core and the estimated ablation indicate that the average annual precipitation above the glacier's equilibrium line is 2400 - 3150 mm, but this needs to be confirmed by long term observation of mass balance.

  14. Late Neogene and Early Quaternary Paleoenvironmental and Paleoclimatic Conditions in Southwestern Europe: Isotopic Analyses on Mammalian Taxa

    Science.gov (United States)

    Domingo, Laura; Koch, Paul L.; Hernández Fernández, Manuel; Fox, David L.; Domingo, M. Soledad; Alberdi, María Teresa

    2013-01-01

    Climatic and environmental shifts have had profound impacts on faunal and floral assemblages globally since the end of the Miocene. We explore the regional expression of these fluctuations in southwestern Europe by constructing long-term records (from ∼11.1 to 0.8 Ma, late Miocene–middle Pleistocene) of carbon and oxygen isotope variations in tooth enamel of different large herbivorous mammals from Spain. Isotopic differences among taxa illuminate differences in ecological niches. The δ13C values (relative to VPDB, mean −10.3±1.1‰; range −13.0 to −7.4‰) are consistent with consumption of C3 vegetation; C4 plants did not contribute significantly to the diets of the selected taxa. When averaged by time interval to examine secular trends, δ13C values increase at ∼9.5 Ma (MN9–MN10), probably related to the Middle Vallesian Crisis when there was a replacement of vegetation adapted to more humid conditions by vegetation adapted to drier and more seasonal conditions, and resulting in the disappearance of forested mammalian fauna. The mean δ13C value drops significantly at ∼4.2−3.7 Ma (MN14–MN15) during the Pliocene Warm Period, which brought more humid conditions to Europe, and returns to higher δ13C values from ∼2.6 Ma onwards (MN16), most likely reflecting more arid conditions as a consequence of the onset of the Northern Hemisphere glaciation. The most notable feature in oxygen isotope records (and mean annual temperature reconstructed from these records) is a gradual drop between MN13 and the middle Pleistocene (∼6.3−0.8 Ma) most likely due to cooling associated with Northern Hemisphere glaciation. PMID:23717470

  15. Water uptake depth analyses using stable water isotopes in rice-based cropping systems in Southeastern Asia

    Science.gov (United States)

    Mahindawansha, Amani; Kraft, Philipp; Orlowski, Natalie; Racela, Healthcliff S. U.; Breuer, Lutz

    2017-04-01

    Rice is one of the most water-consuming crop in the world. Understanding water source utilization of rice-based cropping systems will help to improve water use efficiency (WUE) in paddy management. The objectives of our study were to (1) determine the contributions of various water sources to plant growth in diversified rice-based production systems (wet rice, aerobic rice) (2) investigate water uptake depths at different maturity periods during wet and dry conditions, and (3) calculate WUE of the cropping systems. Our field experiment is based on changes of stable water isotope concentrations in the soil-plant-atmosphere continuum due to transpiration and evaporation. Soil samples were collected together with root sampling from nine different depths under vegetative, reproductive, and matured periods of plant growth together with stem samples. Soil and plant samples were extracted by cryogenic vacuum extraction. Groundwater, surface water, rain, and irrigation water were sampled weekly. All water samples were analyzed for hydrogen and oxygen isotope ratios (δ2H and δ18O) via a laser spectroscope (Los Gatos DLT100). The direct inference approach, which is based on comparing isotopic compositions between plant stem water and soil water, were used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These estimations were used to determine the proportion of water from upper soil horizons and deep horizons for rice in different maturity periods during wet and dry seasons. Shallow soil water has the higher evaporation than from deeper soil water where the highest evaporation effect is at 5 cm depth (drying front). Water uptake is mostly taking place from surface water in the vegetative and between 5-10 cm in the reproductive period, since roots have grown widely and deeper in the reproductive stage. This will be

  16. Coupled zircon Lu-Hf and U-Pb isotopic analyses of the oldest terrestrial crust, the >4.03 Ga Acasta Gneiss Complex

    Science.gov (United States)

    Bauer, Ann M.; Fisher, Christopher M.; Vervoort, Jeffrey D.; Bowring, Samuel A.

    2017-01-01

    The Acasta Gneiss Complex of the Northwest Territories, Canada, contains some of the earliest terrestrial continental crust and thus provides a critical sample set for characterization of crust-forming processes on the early Earth. Here we report the results of a combined Lu-Hf and U-Pb isotopic study of zircons from predominantly felsic orthogneisses from the Acasta Gneiss Complex that crystallized between ∼4.0 and 2.9 Ga, many of which contain complex zoning and therefore require an analytical treatment suited to distinguish amongst compositionally distinct age and Hf isotopic domains. To ensure the reliability of the analyses and of subsequent geologic interpretations, we employed the laser ablation split-stream (LASS) technique to concurrently measure the Lu-Hf and U-Pb isotopic systems in zircon. Our results confirm prior findings of precursor Hadean crust (>4.0 Ga) in the source of these rocks and the continued involvement of this reservoir until ∼3.6 Ga. We present evidence for the input of relatively more juvenile material at ∼3.6 Ga, which we suggest corresponds to a fundamental change in the source of the magmas. This study extends the lower bound of the published Acasta Hf isotopic record from 3.6 Ga to 2.9 Ga and demonstrates that the ∼3.6 Ga-2.9 Ga interval is largely represented by reworking of relatively juvenile ∼3.6 Ga crust and the diminution of the >4.0 Ga crustal signal. Significantly, there is no evidence that rocks within the Acasta Gneiss Complex were derived from a strongly depleted mantle.

  17. Direct lead isotope analysis in Hg-rich sulfides by LA-MC-ICP-MS with a gas exchange device and matrix-matched calibration.

    Science.gov (United States)

    Zhang, Wen; Hu, Zhaochu; Günther, Detlef; Liu, Yongsheng; Ling, Wenli; Zong, Keqing; Chen, Haihong; Gao, Shan

    2016-12-15

    In situ Pb isotope data of sulfide samples measured by LA-MC-ICP-MS provide valuable geochemical information for studies of the origin and evolution of ore deposits. However, the severe isobaric interference of (204)Hg on (204)Pb and the lack of matrix-matched sulfide reference materials limit the precision of Pb isotopic analyses for Hg-rich sulfides. In this study, we observe that Hg forms vapor and can be completely removed from sample aerosol particles produced by laser ablation using a gas exchange device. Additionally, this device does not influence the signal intensities of Pb isotopes. The within-run precision, the external reproducibility and the analytical accuracy are significantly improved for the Hg-rich sulfide samples using this mercury-vapor-removing device. Matrix effects are observed when using silicate glass reference materials as the external standards to assess the relationship of mass fractionation factors between Tl and Pb in sulfide samples, resulting in a maximum deviation of ∼0.20% for (20x)Pb/(204)Pb. Matrix-matched reference materials are therefore required for the highly precise and accurate Pb isotope analyses of sulfide samples. We investigated two sulfide samples, MASS-1 (the Unites States Geological Survey reference materials) and Sph-HYLM (a natural sphalerite), as potential candidates. Repeated analyses of the two proposed sulfide reference materials by LA-MC-ICP-MS yield good external reproducibility of ICP-MS, demonstrating the reliability and robustness of our analytical protocol. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Palaeoecological caracterisation of the mammoth steppe at Final Pleistocene in Central Ukraine from zooarchaeology, stable isotope analyses and direct radiocarbon dating

    Science.gov (United States)

    Péan, Stéphane; Drucker, Dorothée.; Bocherens, Hervé; Haesaerts, Paul; Valladas, Hélène; Stupak, Dmytro; Nuzhnyi, Dmytro

    2010-05-01

    In the Central Ukraine area of the Middle Dnipro Basin, including the Desna river valley, there are exceptional Upper Palaeolithic open air sites with mammoth bone dwelling structures. Mezhyrich is one of these settlements, which are attributed to the Epigravettian cultural facies and occurred in a periglacial environment, during Oxygen Isotope Stage (OIS) 2. Mammoth bone buildings are surrounded by pits, which are filled with archaeological material (tools, hunting weapons, ivory and bone ornaments) and bones of mammoth and other large mammals such as hare, fox, wolf, horse. A new site Buzhanka 2 has yielded a pit which could be related to an expected dwelling structure. These Final Pleistocene sites are particularly appropriate to shed new light upon the relation between man and environment at the time of the mammoth steppe disappearance. Multidisciplinar studies have been carried on, to cross results from zooarchaeology of the pit contents, carbon and nitrogen stable isotope (13C and 15N) analyses of bone collagen, direct 14C dates on mammal bones and microstratigraphic analyses of the loessic sediment. With almost twenty 14C dates available, from mammoth and wolf bones and from charcoals, Mezhyrich is the best dated Epigravettian mammoth bone dwelling site: around 14 500 years BP. Mammoth treatment is zooarchaeologically evidenced in Buzhanka 2, but limited excavated areas do not allow to interpret their procurement yet. In Mezhyrich, consumption of mammoth meat is evidenced from the pit contents, coming from a few juveniles and young adults, probably hunted. The bones used in the dwelling structure no. 4, which are attributed to at least 37 individuals, have two different origins: mostly isolated elements gathered from other deposits, natural accumulations or previous kill sites; a few skeletal portions in anatomical position taken from at least one quite freshly dead mammoth body, for instance a hunted individual. From the stable isotope analyses, it appears

  19. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: A lead isotope study of an Archaean gold prospect in the Attu region, Nagssugtoqidian orogen, West Greenland

    Directory of Open Access Journals (Sweden)

    Stendal, Henrik

    2006-12-01

    Full Text Available This paper presents a lead isotope investigation of a gold prospect south of the village Attu in the northern part of the Nagssugtoqidian orogen in central West Greenland. The Attu gold prospect is a replacement gold occurrence, related to a shear/mylonite zone along a contact between orthogneissand amphibolite within the Nagssugtoqidian orogenic belt. The mineral occurrence is small, less than 0.5 m wide, and can be followed along strike for several hundred metres. The mineral assemblage is pyrite, chalcopyrite, magnetite and gold. The host rocks to the gold prospect are granulite facies ‘brown gneisses’ and amphibolites. Pb-isotopic data on magnetite from the host rocks yield an isochron in a 207Pb/204Pb vs. 206Pb/204Pb diagram, giving a date of 3162 ± 43 Ma (MSWD = 0.5. This date is interpreted to represent the age of the rocks in question, and is older than dates obtained from rocks elsewhere within the Nagssugtoqidian orogen. Pb-isotopic data on cataclastic magnetite from the shear zone lie close to this isochron, indicating a similar origin. The Pb-isotopic compositions of the ore minerals are similar to those previously obtained from the close-by ~2650 Ma Rifkol granite, and suggest a genetic link between the emplacement of this granite and the formation of the ore minerals in the shear/mylonite zone. Consequently, the age of the gold mineralisation is interpreted tobe late Archaean.

  20. Host-dependent differences in resource use associated with Anilocra spp. parasitism in two coral reef fishes, as revealed by stable carbon and nitrogen isotope analyses

    Science.gov (United States)

    Welicky, Rachel; Demopoulos, Amanda W. J.; Sikkel, Paul C.

    2017-01-01

    The role of parasites in trophic ecology is poorly understood in marine ecosystems. Stable isotope analyses (SIA) have been widely used in studies of trophic ecology, but have rarely been applied to study the role of parasites. Considering that some parasites are associated with altered host foraging patterns, SIA can help elucidate whether parasitism influences host trophic interactions. French grunt (Haemulon flavolineatum), an abundant Caribbean coral reef fish, contributes greatly to trophic connectivity. They typically depart the reef at dusk, feed overnight in seagrass beds, and return to the reef at dawn. The large parasitic isopod Anilocra haemuli commonly infects French grunt, and infected fish are less likely to complete their diel migration, and are in poorer condition than uninfected conspecifics. Brown chromis (Chromis multilineata) are diurnally feeding planktivores and infection by Anilocra chromis does not influence host condition. To determine if Anilocra infection influences host diet and foraging locality, we conducted stable carbon and nitrogen isotope analyses on scale, muscle, heart and gill tissues of infected and uninfected French grunt and brown chromis. We determined that all French grunt had δ13C values representative of seagrass habitats, but infected French grunt were significantly enriched in 13C and 15N compared to uninfected conspecifics. This suggests that compared to uninfected conspecifics, infected French grunt forage in seagrass, but on isotopically enriched prey, and/or are in poorer condition, which can elevate δ13C and δ15N values. For brown chromis, infection did not significantly influence any δ13C and δ15N values; hence they all foraged in the same environment and on similar prey. This is the first study to use SIA to examine differences in resource use by Caribbean coral reef fishes associated with parasitism and to evaluate how closely related parasites might have host-dependent effects on host trophic ecology.

  1. Combining Internet monitoring processes, packaging and isotopic analyses to determine the market structure: example of Gamma Butyrolactone.

    Science.gov (United States)

    Pazos, Diego; Giannasi, Pauline; Rossy, Quentin; Esseiva, Pierre

    2013-07-10

    The Internet is becoming more and more popular among drug users. The use of websites and forums to obtain illicit drugs and relevant information about the means of consumption is a growing phenomenon mainly for new synthetic drugs. Gamma Butyrolactone (GBL), a chemical precursor of Gamma Hydroxy Butyric acid (GHB), is used as a "club drug" and also in drug facilitated sexual assaults. Its market takes place mainly on the Internet through online websites but the structure of the market remains unknown. This research aims to combine digital, physical and chemical information to help understand the distribution routes and the structure of the GBL market. Based on an Internet monitoring process, thirty-nine websites selling GBL, mainly in the Netherlands, were detected between January 2010 and December 2011. Seventeen websites were categorized into six groups based on digital traces (e.g. IP addresses and contact information). In parallel, twenty-five bulk GBL specimens were purchased from sixteen websites for packaging comparisons and carbon isotopic measurements. Packaging information showed a high correlation with digital data confirming the links previously established whereas chemical information revealed undetected links and provided complementary information. Indeed, while digital and packaging data give relevant information about the retailers, the supply routes and the distribution close to the consumer, the carbon isotopic data provides upstream information about the production level and in particular the synthesis pathways and the chemical precursors. A three-level structured market has been thereby identified with a production level mainly located in China and in Germany, an online distribution level mainly hosted in the Netherlands and the customers who order on the Internet.

  2. Impact of Forest Harvesting on Trophic Structure of Eastern Canadian Boreal Shield Lakes: Insights from Stable Isotope Analyses

    Science.gov (United States)

    Glaz, Patricia; Sirois, Pascal; Archambault, Philippe; Nozais, Christian

    2014-01-01

    Perturbations on ecosystems can have profound immediate effects and can, accordingly, greatly alter the natural community. Land-use such as forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. The objective of this study was to evaluate the impact of forest harvesting on trophic structure in eastern Canadian Boreal Shield lakes. We measured carbon and nitrogen stable isotopes values for aquatic primary producers, terrestrial detritus, benthic macroinvertebrates, zooplankton and brook trout (Salvelinus fontinalis) over a three-year period in eight eastern Boreal Shield lakes. Four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. Stable isotope mixing models showed leaf-litter to be the main food source for benthic primary consumers in both perturbed and unperturbed lakes, suggesting no logging impact on allochthonous subsidies to the littoral food web. Brook trout derived their food mainly from benthic predatory macroinvertebrates in unperturbed lakes. However, in perturbed lakes one year after harvesting, zooplankton appeared to be the main contributor to brook trout diet. This change in brook trout diet was mitigated two years after harvesting. Size-related diet shift were also observed for brook trout, indicating a diet shift related to size. Our study suggests that carbon from terrestrial habitat may be a significant contribution to the food web of oligotrophic Canadian Boreal Shield lakes. Forest harvesting did not have an impact on the diet of benthic primary consumers. On the other hand, brook trout diet composition was affected by logging with greater zooplankton contribution in perturbed lakes, possibly induced by darker-colored environment in these lakes one year after logging. PMID:24763366

  3. Monitoring Lead (Pb) Pollution and Identifying Pb Pollution Sources in Japan Using Stable Pb Isotope Analysis with Kidneys of Wild Rats

    Science.gov (United States)

    Nakata, Hokuto; Nakayama, Shouta M. M.; Oroszlany, Balazs; Ikenaka, Yoshinori; Mizukawa, Hazuki; Tanaka, Kazuyuki; Harunari, Tsunehito; Tanikawa, Tsutomu; Darwish, Wageh Sobhy; Yohannes, Yared B.; Saengtienchai, Aksorn; Ishizuka, Mayumi

    2017-01-01

    Although Japan has been considered to have little lead (Pb) pollution in modern times, the actual pollution situation is unclear. The present study aims to investigate the extent of Pb pollution and to identify the pollution sources in Japan using stable Pb isotope analysis with kidneys of wild rats. Wild brown (Rattus norvegicus, n = 43) and black (R. rattus, n = 98) rats were trapped from various sites in Japan. Mean Pb concentrations in the kidneys of rats from Okinawa (15.58 mg/kg, dry weight), Aichi (10.83), Niigata (10.62), Fukuoka (8.09), Ibaraki (5.06), Kyoto (4.58), Osaka (4.57), Kanagawa (3.42), and Tokyo (3.40) were above the threshold (2.50) for histological kidney changes. Similarly, compared with the previous report, it was regarded that even structural and functional kidney damage as well as neurotoxicity have spread among rats in Japan. Additionally, the possibility of human exposure to a high level of Pb was assumed. In regard to stable Pb isotope analysis, distinctive values of stable Pb isotope ratios (Pb-IRs) were detected in some kidney samples with Pb levels above 5.0 mg/kg. This result indicated that composite factors are involved in Pb pollution. However, the identification of a concrete pollution source has not been accomplished due to limited differences among previously reported values of Pb isotope composition in circulating Pb products. Namely, the current study established the limit of Pb isotope analysis for source identification. Further detailed research about monitoring Pb pollution in Japan and the demonstration of a novel method to identify Pb sources are needed. PMID:28075384

  4. Monitoring Lead (Pb Pollution and Identifying Pb Pollution Sources in Japan Using Stable Pb Isotope Analysis with Kidneys of Wild Rats

    Directory of Open Access Journals (Sweden)

    Hokuto Nakata

    2017-01-01

    Full Text Available Although Japan has been considered to have little lead (Pb pollution in modern times, the actual pollution situation is unclear. The present study aims to investigate the extent of Pb pollution and to identify the pollution sources in Japan using stable Pb isotope analysis with kidneys of wild rats. Wild brown (Rattus norvegicus, n = 43 and black (R. rattus, n = 98 rats were trapped from various sites in Japan. Mean Pb concentrations in the kidneys of rats from Okinawa (15.58 mg/kg, dry weight, Aichi (10.83, Niigata (10.62, Fukuoka (8.09, Ibaraki (5.06, Kyoto (4.58, Osaka (4.57, Kanagawa (3.42, and Tokyo (3.40 were above the threshold (2.50 for histological kidney changes. Similarly, compared with the previous report, it was regarded that even structural and functional kidney damage as well as neurotoxicity have spread among rats in Japan. Additionally, the possibility of human exposure to a high level of Pb was assumed. In regard to stable Pb isotope analysis, distinctive values of stable Pb isotope ratios (Pb-IRs were detected in some kidney samples with Pb levels above 5.0 mg/kg. This result indicated that composite factors are involved in Pb pollution. However, the identification of a concrete pollution source has not been accomplished due to limited differences among previously reported values of Pb isotope composition in circulating Pb products. Namely, the current study established the limit of Pb isotope analysis for source identification. Further detailed research about monitoring Pb pollution in Japan and the demonstration of a novel method to identify Pb sources are needed.

  5. Monitoring Lead (Pb) Pollution and Identifying Pb Pollution Sources in Japan Using Stable Pb Isotope Analysis with Kidneys of Wild Rats.

    Science.gov (United States)

    Nakata, Hokuto; Nakayama, Shouta M M; Oroszlany, Balazs; Ikenaka, Yoshinori; Mizukawa, Hazuki; Tanaka, Kazuyuki; Harunari, Tsunehito; Tanikawa, Tsutomu; Darwish, Wageh Sobhy; Yohannes, Yared B; Saengtienchai, Aksorn; Ishizuka, Mayumi

    2017-01-10

    Although Japan has been considered to have little lead (Pb) pollution in modern times, the actual pollution situation is unclear. The present study aims to investigate the extent of Pb pollution and to identify the pollution sources in Japan using stable Pb isotope analysis with kidneys of wild rats. Wild brown (Rattus norvegicus, n = 43) and black (R. rattus, n = 98) rats were trapped from various sites in Japan. Mean Pb concentrations in the kidneys of rats from Okinawa (15.58 mg/kg, dry weight), Aichi (10.83), Niigata (10.62), Fukuoka (8.09), Ibaraki (5.06), Kyoto (4.58), Osaka (4.57), Kanagawa (3.42), and Tokyo (3.40) were above the threshold (2.50) for histological kidney changes. Similarly, compared with the previous report, it was regarded that even structural and functional kidney damage as well as neurotoxicity have spread among rats in Japan. Additionally, the possibility of human exposure to a high level of Pb was assumed. In regard to stable Pb isotope analysis, distinctive values of stable Pb isotope ratios (Pb-IRs) were detected in some kidney samples with Pb levels above 5.0 mg/kg. This result indicated that composite factors are involved in Pb pollution. However, the identification of a concrete pollution source has not been accomplished due to limited differences among previously reported values of Pb isotope composition in circulating Pb products. Namely, the current study established the limit of Pb isotope analysis for source identification. Further detailed research about monitoring Pb pollution in Japan and the demonstration of a novel method to identify Pb sources are needed.

  6. Determination of the geographic origin of rice by chemometrics with strontium and lead isotope ratios and multielement concentrations.

    Science.gov (United States)

    Ariyama, Kaoru; Shinozaki, Miyuki; Kawasaki, Akira

    2012-02-22

    The objective of this study was to develop a technique for determining the country of origin of rice in the Japanese market. The rice samples included a total of 350 products grown in Japan (n = 200), the United States (n = 50), China (n = 50), and Thailand (n = 50). In this study, (87)Sr/(86)Sr and Pb isotope ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) ratios and multielement concentrations (Al, Fe, Co, Ni, Cu, Rb, Sr, and Ba) were determined by high-resolution inductively coupled plasma mass spectrometry. By combining three chemometric techniques based on different principles and determination criteria, the countries of origin of rice were determined. The predictions made by 10-fold cross-validation were around 97% accurate. The presented method demonstrated the effectiveness of determining the geographic origin of an agricultural product by combining several chemometric techniques using heavy element isotope ratios and multielement concentrations.

  7. A late Pleistocene refugium in Mediterranean North Africa? Palaeoenvironmental reconstruction from stable isotope analyses of land snail shells (Haua Fteah, Libya)

    Science.gov (United States)

    Prendergast, A. L.; Stevens, R. E.; O'Connell, T. C.; Hill, E. A.; Hunt, C. O.; Barker, G. W.

    2016-05-01

    The late Pleistocene to Holocene archaeological record of North Africa is key to understanding the emergence of anatomically modern humans into West Asia and Europe, and the broadening of subsistence strategies in the shift from hunter-gatherer to pastoral-agricultural lifeways. Some contend that these developments were modulated by major shifts in climate and environment. Evaluation of this hypothesis requires the pairing of local and regional climate records with well-dated archaeological sequences. The Haua Fteah archaeological site in the Gebel Akhdar region of Libya provides a key site to test this hypothesis as the cave contains one of the longest and most complete sequences of human occupation in North Africa as well as abundant material for palaeoenvironmental reconstruction. This study uses stable isotope analyses (δ18O and δ13C) of the terrestrial mollusc Helix melanostoma to construct a palaeoenvironmental framework for interpreting North African human-environment interactions from the Upper Palaeolithic to the Neolithic (∼30,000 to 5000 years ago). The land snail stable isotope records from Haua Fteah suggests that cool arid conditions in the cave peaked during marine isotope stage (MIS) 2. This stage was, however, only marginally drier than previous and subsequent stages and coincided with an increase in occupation density in the cave. This suggests that the Gebel Akhdar may have served as an environmental refugium from the more extreme aridity in the surrounding Sahara and arid coastal plains for Late Stone Age (LSA) populations in North Africa. Conditions became progressively wetter towards the Holocene. However, generally wetter conditions were interrupted by two arid episodes at c. 8.0 ka and 7.3 ka that appear to coincide with regional changes reflected elsewhere in the Mediterranean basin.

  8. Aerobic respiration along isopycnals leads to overestimation of the isotope effect of denitrification in the ocean water column

    Science.gov (United States)

    Marconi, Dario; Kopf, Sebastian; Rafter, Patrick A.; Sigman, Daniel M.

    2017-01-01

    The nitrogen (N) isotopes provide an integrative geochemical tool for constraining the fixed N budget of the ocean. However, N isotope budgeting requires a robust estimate for the organism-scale nitrogen isotope effect of denitrification, in particular as it occurs in water column denitrification zones (εwcd). Ocean field data interpreted with the Rayleigh model have typically yielded estimates for εwcd of between 20 and 30‰. However, recent findings have raised questions about this value. In particular, culture experiments can produce a substantially lower isotope effect (∼13‰) under conditions mimicking those of ocean suboxic zones. In an effort to better understand prior field estimates of εwcd, we use a geochemical multi-box model to investigate the combined effects of denitrification, aerobic respiration, and isopycnal exchange on the δ15N of nitrate. In the context of this admittedly simplistic model, we consider three isopycnals extending from the Southern Ocean to the Eastern Tropical North Pacific (ETNP). We show that the data from the ETNP suboxic zone can be reproduced with an εwcd of 13‰, given a rate of aerobic respiration consistent with the nutrient data on these isopycnals and a plausible range in the δ15N of the sinking flux being remineralized. We discuss the limitations of our analysis, additional considerations, as well as possible data-based tests for the proposal of a lower εwcd than previously estimated. All else held constant, a lower εwcd would imply a lower global ocean rate of denitrification that is more similar to the estimated rate of N input to the global ocean, providing a major impetus for further investigation.

  9. Anthropogenic influences on Pb/Al and lead isotope signature in annually layered Holocene Maar lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Schettler, G.; Romer, R.L. [GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam (Germany)

    1998-08-01

    Annually laminated sediments from two Maar lakes in the West Eifel volcanic field (Germany) show anomalously high Pb within sections deposited during the first centuries A.D. exceeding the local geological background 8.5-fold in Lake Meerfelder Maar (MFM) and 4-fold in Lake Schalkenmehrener Maar (SMM). These Pb anomalies are associated with a distinct shift in the Pb isotope signature to less radiogenic compositions. The excess Pb causing the anomaly has the same isotopic composition as galena deposits 60 km to the NW of the Maar lakes. It is suggested that this component was transported airborne into the Maar lakes and originates from regional Roman Pb refinement and cupellation of argentiferous Pb. Varve chronostratigraphy of correlated cores indicates that significant Roman Pb input lasted for about 230 a. SMM does not get fluviatile input. Its sedimentary record is more sensitive to variations in airborne input than that of MFM, which had an inflow. SMM sediment sections deposited during periods of low soil erosion (early Holocene, Dark Ages) with comparably high Pb/Al values also show little radiogenic Pb. This is caused by airborne minerogenic matter from a geochemically and isotopically distinct remote source that becomes apparent only in sedimentation periods of very restricted local allochthonous input. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Holocene environmental change in the eastern Snake River Plain of Idaho, USA, as inferred from stable isotope analyses of small mammals

    Science.gov (United States)

    Commendador, Amy S.; Finney, Bruce P.

    2016-05-01

    Previous research on the small mammal population recovered from archeological excavations at the Wasden Site in southeastern Idaho suggests that changing frequency distributions through time represent a shift in climate during the early Holocene from a cooler, wetter regime to a warmer, drier one. This conclusion was re-evaluated using stable carbon and nitrogen isotope analyses of bone collagen from the three species of small mammals examined in the earlier studies: pocket gophers (Thomomys talpoides), pygmy rabbits (Brachylagus idahoensis), and ground squirrels (Spermophilus townsendii). Resulting carbon and nitrogen isotopic values are consistent with known differences in feeding ecology, suggesting high fidelity as proxies for past vegetation (and thus climate) regimes. Patterns of 15N enrichment and increased representation of C4-CAM vegetation observed in the pocket gophers, and to a lesser extent ground squirrels, suggests increasing warmth and/or aridity from the early Holocene until ∼7000 cal yr BP, thus supporting previous hypotheses of climate change on the eastern Snake River Plain. The results highlight the potential contribution of such studies for archeological research by providing additional proxies for environmental conditions that bear on paleoecological adaptations to climatic change, including past human use and occupation of the region.

  11. Isotopic analyses and calculation by use of JENDL-3.2 for high burn-up UO{sub 2} and MOX spent fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sasahara, Akihiro; Matsumura, Tetsuo [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab.; Nicolaou, G.; Betti, M.; Walker, C.T.

    1997-03-01

    The post irradiation examinations (PIE) were carried out for high burn-up UO{sub 2} spent fuel (3.8%U235, average burn-up:60GWd/t) and mixed oxide (MOX) spent fuel (5.07%Pu, average burn-up:45GWd/t). The PIE includes, (a) isotopic analysis, (b) electron probe microanalysis (EPMA) in pellet cross section and so on. The results of isotopic analyses and EPMA were compared with ORIGEN2/82 and VIM-BURN calculation results. In VIM-BURN calculation, the nuclear data of actinides were proceeded from new data file, JENDL-3.2. The sensitivities of power history and moderator density to nuclides composition were investigated by VIM-BURN calculation and consequently power history mainly effected on Am241 and Am242m and moderator density effected on fissile nuclides. From EPMA results of U and Pu distribution in pellet, VIM-BURN calculation showed reasonable distribution in pellet cross section. (author)

  12. Trophic Dynamics of Filter Feeding Bivalves in the Yangtze Estuarine Intertidal Marsh: Stable Isotope and Fatty Acid Analyses.

    Directory of Open Access Journals (Sweden)

    Sikai Wang

    Full Text Available Benthic bivalves are important links between primary production and consumers, and are essential intermediates in the flow of energy through estuarine systems. However, information on the diet of filter feeding bivalves in estuarine ecosystems is uncertain, as estuarine waters contain particulate matter from a range of sources and as bivalves are opportunistic feeders. We surveyed bivalves at different distances from the creek mouth at the Yangtze estuarine marsh in winter and summer, and analyzed trophic dynamics using stable isotope (SI and fatty acid (FA techniques. Different bivalve species had different spatial distributions in the estuary. Glauconome chinensis mainly occurred in marshes near the creek mouth, while Sinonovacula constricta preferred the creek. Differences were found in the diets of different species. S. constricta consumed more diatoms and bacteria than G. chinensis, while G. chinensis assimilated more macrophyte material. FA markers showed that plants contributed the most (38.86 ± 4.25% to particular organic matter (POM in summer, while diatoms contributed the most (12.68 ± 1.17% during winter. Diatoms made the largest contribution to the diet of S. constricta in both summer (24.73 ± 0.44% and winter (25.51 ± 0.59%, and plants contributed no more than 4%. This inconsistency indicates seasonal changes in food availability and the active feeding habits of the bivalve. Similar FA profiles for S. constricta indicated that the bivalve had a similar diet composition at different sites, while different δ13C results suggested the diet was derived from different carbon sources (C4 plant Spartina alterniflora and C3 plant Phragmites australis and Scirpus mariqueter at different sites. Species-specific and temporal and/or spatial variability in bivalve feeding may affect their ecological functions in intertidal marshes, which should be considered in the study of food webs and material flows in estuarine ecosystems.

  13. Near Infrared Cavity Ring-Down Spectroscopy for Isotopic Analyses of CH4 on Future Martian Surface Missions

    Science.gov (United States)

    Chen, Y.; Mahaffy P.; Holmes, V.; Burris, J.; Morey, P.; Lehmann, K.K.; Lollar, B. Sherwood; Lacrampe-Couloume, G.; Onstott, T.C.

    2014-01-01

    A compact Near Infrared Continuous Wave Cavity Ring-Down Spectrometer (near-IR-cw-CRDS) was developed as a candidate for future planetary surface missions. The optical cavity was made of titanium with rugged quartz windows to protect the delicate super cavity from the harsh environmental changes that it would experience during space flight and a Martian surface mission. This design assured the long-term stability of the system. The system applied three distributed feedback laser diodes (DFB-LD), two of which were tuned to the absorption line peaks of (sup 12)CH4 and (sup 13)CH4 at 6046.954 inverse centimeters and 6049.121 inverse centimeters, respectively. The third laser was tuned to a spectral-lines-free region for measuring the baseline cavity loss. The multiple laser design compensated for typical baseline drift of a CRDS system and, thus, improved the overall precision. A semiconductor optical amplifier (SOA) was used instead of an Acousto-Optic Module (AOM) to initiate the cavity ring-down events. It maintained high acquisition rates such as AOM, but consumed less power. High data acquisition rates combined with improved long-term stability yielded precise isotopic measurements in this near-IR region even though the strongest CH4 absorption line in this region is 140 times weaker than that of the strongest mid-IR absorption band. The current system has a detection limit of 1.4 times 10( sup –12) inverse centimeters for (sup 13)CH4. This limit corresponds to approximately 7 parts per trillion volume of CH4 at 100 Torrs. With no further improvements the detection limit of our current near IR-cw-CRDS at an ambient Martian pressure of approximately 6 Torrs (8 millibars) would be 0.25 parts per billion volume for one 3.3 minute long analysis.

  14. Ore genesis constraints on the Idaho Cobalt Belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses

    Science.gov (United States)

    Hofstra, Albert H.; Landis, Gary P.

    2012-01-01

    The Idaho cobalt belt is a 60-km-long alignment of deposits composed of cobaltite, Co pyrite, chalcopyrite, and gold with anomalous Nb, Y, Be, and rare-earth elements (REEs) in a quartz-biotite-tourmaline gangue hosted in Mesoproterozoic metasedimentary rocks of the Lemhi Group. It is the largest cobalt resource in the United States with historic production from the Blackbird Mine. All of the deposits were deformed and metamorphosed to upper greenschist-lower amphibolite grade in the Cretaceous. They occur near a 1377 Ma anorogenic bimodal plutonic complex. The enhanced solubility of Fe, Co, Cu, and Au as chloride complexes together with gangue biotite rich in Fe and Cl and gangue quartz containing hypersaline inclusions allows that hot saline fluids were involved. The isotopes of B in gangue tourmaline are suggestive of a marine source, whereas those of Pb in ore suggest a U ± Th-enriched source. The ore and gangue minerals in this belt may have trapped components in fluid inclusions that are distinct from those in post-ore minerals and metamorphic minerals. Such components can potentially be identified and distinguished by their relative abundances in contrasting samples. Therefore, we obtained samples of Co and Cu sulfides, gangue quartz, biotite, and tourmaline and post-ore quartz veins as well as Cretaceous metamorphic garnet and determined the gas, noble gas isotope, and ion ratios of fluid inclusion extracts by mass spectrometry and ion chromatography. The most abundant gases present in extracts from each sample type are biased toward the gas-rich population of inclusions trapped during maximum burial and metamorphism. All have CO2/CH4 and N2/Ar ratios of evolved crustal fluids, and many yield a range of H2-CH4-CO2-H2S equilibration temperatures consistent with the metamorphic grade. Cretaceous garnet and post-ore minerals have high RH and RS values suggestive of reduced sulfidic conditions. Most extracts have anomalous 4He produced by decay of U and Th and

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

    Science.gov (United States)

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

    2012-02-29

    This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and 206Pb/207Pb/208Pb, 238U/234U and 232Th/230Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA® extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. A study of radionuclides, metals and stable lead isotope ratios in sediments and soils in the vicinity of natural U-mineralisation areas in the Northern Territory

    Energy Technology Data Exchange (ETDEWEB)

    Frostick, A., E-mail: Alison.Frostick@cdu.edu.au [Charles Darwin University, School of Environment and Life Sciences, Darwin NT 0909 (Australia); ERISS, GPO Box 461, Darwin NT 0801 (Australia); Bollhoefer, A. [ERISS, GPO Box 461, Darwin NT 0801 (Australia); Parry, D. [AIMS, PO Box 41775, Casuarina NT 0811 (Australia)

    2011-10-15

    Australian guidelines recommend that tailings materials from uranium (U) mining and milling be contained without any detrimental impact on the environment for at least 1000 years. Natural analogue sites are being investigated to determine if they can provide data on the rates of natural erosion processes which occur over these timescales, for input into predictive geomorphic computer models. This paper presents radionuclide, metal and stable lead (Pb) isotope data from sediment cores and surface soils in the vicinity of two mineralised areas in the Alligator Rivers Region. Surface scrapes from the natural Anomaly no. 2, south of the Ranger mineral lease, exhibit radiogenic {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios, and elevated U and metal concentrations typical for a near surface U anomaly. In contrast, samples taken from the Koongarra mineral lease (KML) show radionuclide activity and metal concentrations similar to natural areas elsewhere in the Alligator Rivers Region and Pb isotope ratios are closer to present day average crustal ratios (PDAC), as the orebodies at KML are covered by surficial sand. A sediment core collected from Anbangbang Billabong, downstream of KML, exhibits small variations in Pb isotope ratios that indicate that approximately 1% of the upper sediments in the sediment core may be derived from material originating from the U anomaly at Koongarra.

  17. The electrooxidation mechanism of formic acid on platinum and on lead ad-atoms modified platinum studied with the kinetic isotope effect

    Science.gov (United States)

    Bełtowska-Brzezinska, M.; Łuczak, T.; Stelmach, J.; Holze, R.

    2014-04-01

    Kinetics and mechanism of formic acid (FA) oxidation on platinum and upd-lead ad-atoms modified platinum electrodes have been studied using unlabelled and deuterated compounds. Poisoning of the electrode surface by CO-like species was prevented by suppression of dissociative chemisorption of FA due to a fast competitive underpotential deposition of lead ad-atoms on the Pt surface from an acidic solution containing Pb2+ cations. Modification of the Pt electrode with upd lead induced a catalytic effect in the direct electrooxidation of physisorbed FA to CO2. With increasing degree of H/D substitution, the rate of this reaction decreased in the order: HCOOH > DCOOH ≥ HCOOD > DCOOD. HCOOH was oxidized 8.5-times faster on a Pt/Pb electrode than DCOOD. This primary kinetic isotope effect proves that the C-H- and O-H-bonds are simultaneously cleaved in the rate determining step. A secondary kinetic isotope effect was found in the dissociative chemisorption of FA in the hydrogen adsorption-desorption range on a bare Pt electrode after H/D exchange in the C-H bond, wherein the influence of deuterium substitution in the O-H group was negligibly small. Thus the C-H bond cleavage is accompanied by the C-OH and not the O-H bond split in the FA decomposition, producing CO-like species on the Pt surface sites.

  18. Determination of the provenance of cocoa by soil protolith ages and assessment of anthropogenic lead contamination by pb/nd and lead isotope ratios.

    Science.gov (United States)

    Manton, William I

    2010-01-27

    The Pb contents of chocolate and the products it flavors are among the highest of all commonly consumed substances. Others have shown that this Pb is acquired by cocoa beans after harvesting and is concentrated in their shells, portions of which are ground up with the cotyledons during processing. It is shown here that the shells also contain the lanthanides Nd and Sm, which they appear to take up more slowly than Pb when dried on bare soil. Consideration of Pb/Nd ratios, model Sm-Nd ages and the isotope ratios of Pb and Sr indicates that, in the absence of contamination, the relationship between Pb and Nd in shells is y = 13.1x(-0.383), where x is the Nd concentration in microg/kg and y is the Pb/Nd ratio. For cocoa powders, the relationship is y = 114x(-0.988). Samples that plot above these curves are probably contaminated. Model ages indicate where the cocoa of cocoa powders is grown, and these same considerations point to African samples being uncontaminated but samples from Asia containing 50% anthropogenic Pb of Australian origin. No measurable Pb contamination occurs during the transport of beans and the manufacture of chocolate.

  19. Helium, lead and sulfur isotope geochemistry of the Gejiu Sn-polymetallic ore deposit and the sources of ore-forming materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Studies on the helium, lead and sulfur isotopic composition were performed of the Gejiu super-large Sn-polymetallic ore deposit. The results indicated that the ore-forming materials came from different sources and the deposit is a product of superimposed mineralization. The deposit is characterized by multi-source and multi-period mineralization, which experienced submarine hydrothermal deposition and Late Yanshanian magmatic hydrothermal mineralization. It is held that the Gejiu super-large Sn-polymetallic ore deposit is a multi-genesis deposit.

  20. Signature lipids and stable carbon isotope analyses of Octopus Spring hyperthermophilic communities compared with those of Aquificales representatives

    Science.gov (United States)

    Jahnke, L. L.; Eder, W.; Huber, R.; Hope, J. M.; Hinrichs, K. U.; Hayes, J. M.; Des Marais, D. J.; Cady, S. L.; Summons, R. E.

    2001-01-01

    The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C(20:1) and cy-C(21) fatty acids dominated all of the Aquificales, while the alkyl glycerol ethers were mainly C(18:0). These Aquificales biomarkers were major constituents of the lipid extracts of two Octopus Spring samples, a biofilm associated with the siliceous vent walls, and the well-known pink streamer community (PSC). Both the biofilm and the PSC contained mono- and dialkyl glycerol ethers in which C(18) and C(20) alkyl groups were prevalent. Phospholipid fatty acids included both the Aquificales n-C(20:1) and cy-C(21), plus a series of iso-branched fatty acids (i-C(15:0) to i-C(21:0)), indicating an additional bacterial component. Biomass and lipids from the PSC were depleted in (13)C relative to source water CO(2) by 10.9 and 17.2 per thousand, respectively. The C(20-21) fatty acids of the PSC were less depleted than the iso-branched fatty acids, 18.4 and 22.6 per thousand, respectively. The biomass of T. ruber grown on CO(2) was depleted in (13)C by only 3.3 per thousand relative to C source. In contrast, biomass was depleted by 19.7 per thousand when formate was the C source. Independent of carbon source, T. ruber lipids were heavier than biomass (+1.3 per thousand). The depletion in the C(20-21) fatty acids from the PSC indicates that Thermocrinis biomass must be similarly depleted and too light to be explained by growth on CO(2). Accordingly, Thermocrinis in the PSC is likely to have utilized formate, presumably generated in the spring source region.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mas, J.L., E-mail: ppmasb@us.es [Dpto. Fisica Aplicada I, EPS, Universidad de Sevilla, 41012 Sevilla (Spain); Villa, M. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain); Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes 4b, 41012 Sevilla (Spain); Garcia-Tenorio, R. [Dpto. Fisica Aplicada II, ETS de Arquitectura, Universidad de Sevilla, Avda. Reina Mercedes 2, 41012 Sevilla (Spain)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Polluted sediment and NORM samples. Black-Right-Pointing-Pointer An efficient yet fast process allowing multi-parametric determinations in <3 days. Black-Right-Pointing-Pointer Trace element concentrations, Pb, Th and U isotope ratios with a single instrument. - Abstract: This work focuses on the monitoring of the potential pollution in scenarios that involve NORM-related industrial activities (environmental or in-door scenarios). The objective was to develop a method to determine extent and origin of the contamination, suitable for monitoring (i.e. simple, fast and economical) and avoiding the use of too many different instruments. It is presented a radiochemical method that allows the determination of trace element concentrations and {sup 206}Pb/{sup 207}Pb/{sup 208}Pb, {sup 238}U/{sup 234}U and {sup 232}Th/{sup 230}Th isotope ratios using a single sample aliquot and a single instrument (ICP-QMS). Eichrom UTEVA{sup Registered-Sign} extraction chromatography minicolumns were used to separate uranium and thorium in sample leachates. Independent ICP-MS determinations of uranium and thorium isotope ratios were carried out afterwards. Previously a small aliquot of the leachate was used for the determination of trace element concentrations and lead isotope ratios. Several radiochemical arrangements were tested to get maximum performances and simplicity of the method. The performances of the method were studied in terms of chemical yields of uranium and thorium and removal of the potentially interfering elements. The established method was applied to samples from a chemical industry and sediments collected in a NORM-polluted scenario. The results obtained from our method allowed us to infer not only the extent, but also the sources of the contamination in the area.

  2. Uranium-Lead Zircon Ages and Sr, Nd, and Pb Isotope Geochemistry of Selected Plutonic Rocks from Western Idaho

    Science.gov (United States)

    Unruh, Daniel M.; Lund, Karen; Kuntz, Mel A.; Snee, Lawrence W.

    2008-01-01

    Across the Salmon River suture in western Idaho, where allochthonous Permian to Cretaceous oceanic rocks are juxtaposed against Proterozoic North American rocks, a wide variety of plutonic rocks are exposed. Available data indicate much variation in composition, source, and structural state of these plutons. The plutonic rocks were long described as the western border zone of the Cretaceous Idaho batholith but limited pre-existing age data indicate more complicated origins. Because the affinity and age of the plutonic rocks cannot be reliably determined from field relations, TIMS U-Pb dating in conjunction with Sr, Nd, and Pb isotopic studies of selected plutons across the suture in western Idaho were undertaken. The data indicate three general groups of plutons including (1) those that intruded the island arc terranes during the Triassic and Jurassic, those that intruded near the western edge of oceanic rocks along the suture in the Early Cretaceous, and the plutons of the Idaho batholith that intruded Proterozoic North American rocks in the Late Cretaceous. Plutons that intruded Proterozoic North American rocks commonly include xenocrystic zircons and in several cases, ages could not be determined. The least radiogenic Sr and most radiogenic Nd are found among the Blue Mountains superterrane island arc samples. Suture-zone plutons have isotopic characteristics that span the range between Idaho batholith and island arc samples but mostly follow island arc signatures. Plutons of the Idaho batholith have the most radiogenic initial Pb and Sr ratios and the least radiogenic Nd of the samples analyzed.

  3. Lead as transient geochemical tracers in the environment: Assessing high precision isotope ratio measurements in lichens, peat, and silicates using multi-collector ICP-MS

    Science.gov (United States)

    Weiss, D. J.; Kober, B.; Mason, T. F.; Dolgopolova, A.; Coles, B. J.; Gallagher, K.; Leroux, G.; Spiro, B.; Seltmann, R.

    2003-04-01

    In recent years, MC-ICP-MS has become a powerful tool to measure Pb isotopes with high precision and accuracy. Yet, this technique is still relatively new, and the complexities related to using an ICP ion source for high precision isotope measurements are only now becoming apparent. In addition, most analytical development work so far has focussed on synthetic solutions and silicate material. Given the great importance of Pb isotopes in environmental geochemical studies, however, a careful assessment of analytical procedures for environmental samples is clearly needed and warranted. Consequently, we present here a study of the analytical performance of the Imperial College/Natural History Museum (IC/NHM) IsoProbe MC-ICPMS with respect to high precision Pb isotope measurements in peat, lichen and silicates. After acid digestion, the samples were passed through an exchange column using a new procedure developed at the University of Heidelberg (Kober, in prep.). This chemistry yielded quantitative recoveries and allowed a high sample throughput as only one column passage was needed to achieve stable ion beam signals. Selected samples were also analysed on a Finnegan MAT261 TIMS. Typical internal precisions of 10-35 ppm (1se) were achieved on all Pb isotope ratios in all matrices. Measurements of Pb 981 NIST standards spiked with Tl 997 NIST showed that the certified NBS Tl ratio had to be adjusted daily up to 2.38993 in order to obtain accurate data. The reproducibility for the synthetic standard over a three month period using daily optimised Tl values (but with no 2σ outlier rejection routine applied) was below 300 ppm for all ratios (including the 208Pb/204Pb ratio). On peak zeroing (OPZ) and half mass baseline correction procedures gave similar precisions. However, the accuracies on the 204 ratios were significantly worse using half mass baseline correction for Pb/Tl ratios less than 2. This behaviour is consistent with tailing of 205Tl onto the 204Pb peak

  4. The relationship of bone and blood lead to hypertension: Further analyses of the normative aging study data

    Energy Technology Data Exchange (ETDEWEB)

    Hu, H.; Kim, Rokho; Korrick, S. [Harvard Medical School, Boston, MA (United States)]|[Harvard Health of Public Health, Boston, MA (United States); Rotnitzky, A. [Harvard School of Public Health, Boston, MA (United States)] [and others

    1996-12-31

    In an earlier report based on participants in the Veterans Administration Normative Aging Study, we found a significant association between the risk of hypertension and lead levels in tibia. To examine the possible confounding effects of education and occupation, we considered in this study five levels of education and three levels of occupation as independent variables in the statistical model. Of 1,171 active subjects seen between August 1991 and December 1994, 563 provided complete data for this analysis. In the initial logistic regression model, acre and body mass index, family history of hypertension, and dietary sodium intake, but neither cumulative smoking nor alcohol ingestion, conferred increased odds ratios for being hypertensive that were statistically significant. When the lead biomarkers were added separately to this initial logistic model, tibia lead and patella lead levels were associated with significantly elevated odds ratios for hypertension. In the final backward elimination logistic regression model that included categorical variables for education and occupation, the only variables retained were body mass index, family history of hypertension, and tibia lead level. We conclude that education and occupation variables were not confounding the association between the lead biomarkers and hypertension that we reported previously. 27 refs., 3 tabs.

  5. Diversity of trophic niches among herbivorous fishes on a Caribbean reef (Guadeloupe, Lesser Antilles), evidenced by stable isotope and gut content analyses

    Science.gov (United States)

    Dromard, Charlotte R.; Bouchon-Navaro, Yolande; Harmelin-Vivien, Mireille; Bouchon, Claude

    2015-01-01

    While herbivorous fishes have been widely studied due to the major ecological role they play on coral reefs, the description of their trophic niche remains challenging. In this study, we asked how 10 species of parrotfishes and surgeonfishes partition trophic resources on a Caribbean reef. The determination of trophic niches was conducted using gut and stomach content and stable isotope analyses (15N:14N and 13C:12C ratios). The contributions of food source to fish diet were calculated with concentration-dependent mixing models. Stomach content analyses distinguished two species of Acanthuridae from other fish species: Acanthurus coeruleus due to its high ingestion of fleshy macroalgae and Acanthurus chirurgus due to its high ingestion of calcified macroalgae. Acanthuridae and Sparisoma aurofrenatum presented similar diets in terms of assimilation of food resources with a high contribution of detritus and invertebrates to their diets. The diets of Sparisoma rubripinne and Sparisoma chrysopterum were more heterogeneous by comparison to the previous species. Scarus iseri, Scarus vetula, Scarus taeniopterus and Sparisoma viride appeared to share a similar trophic niche characterized by the contribution of live coral and fleshy macroalgae to their diet. The resource use among herbivorous fishes was partially related to the nutritional quality of food sources, but also to their physical structure and the capacity of fish to process them efficiently. These results showed that the ten species occupy distinct trophic niches, indicating a high functional diversity among the Caribbean herbivorous fishes.

  6. Study of the Lead Source in the Surrounding Soil of the Lead-zinc Smelters by Isotope Tracing%铅锌冶炼厂周边土壤铅源的铅同位素示踪

    Institute of Scientific and Technical Information of China (English)

    于凯; 李旭祥; 支泽林; 王海波; 郑刘孙

    2014-01-01

    Taken the soil samples nearby a lead-zinc smelter as the research object,the lead content of the lead-zinc ore,the metallurgical coal and the nearby soil were detected.It was concluded that lead content in the soil surrounding the lead-zinc smelter varied from 22.73 mg/kg to 126.51 mg/kg,and the average content was 42.68 mg/kg which was higher by a factor of 1.85 than the local soil background level.Meanwhile the possible contamination sources were analyzed by means of the spatial variability analysis and the lead isotope mixed model formula.It was concluded that the spatial distribution of soil heavy metal nearby the lead-zinc smelter and the lead isotope rates were close to the metallurgical coal and so that the metallurgical coal was the largest contribu-tion to the soil pollution.%以某铅锌冶炼厂周边土壤为研究对象,通过对其原料及周边土壤中铅含量的检测,结果显示:该冶炼厂周边土壤铅质量比在22.73 mg/kg~126.51 mg/kg之间,平均值为42.68 mg/kg,是当地土壤铅背景值的1.85倍。采用铅质量比空间分布分析和同位素混合模型计算分析了冶炼厂周边土壤中铅的可能来源,分析表明:土壤铅质量比的空间分布及铅同位素比值与冶炼厂的焦化原料煤相近,焦化原料煤对周边土壤铅污染贡献最大。

  7. Identifying the sources of nitrate contamination of groundwater in an agricultural area (Haean basin, Korea) using isotope and microbial community analyses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heejung [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of); Kaown, Dugin, E-mail: dugin1@snu.ac.kr [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of); Mayer, Bernhard [Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary T2N 1N4, Alberta (Canada); Lee, Jin-Yong [Department of Geology, Kangwon National University, Chuncheon 200–701 (Korea, Republic of); Hyun, Yunjung [Planning and Management Group, Korea Environment Institute, Sejong 339-007 (Korea, Republic of); Lee, Kang-Kun [School of Earth and Environmental Sciences (BK21 SEES), Seoul National University, Seoul 151–747 (Korea, Republic of)

    2015-11-15

    } and SO{sub 4}{sup 2−} in groundwater in areas with intensive agricultural land use. - Highlights: • Dual isotope analyses identified contaminant sources. • Aquifer contamination was affected by land use. • Microbial community in groundwater reflects land use. • Approach is promising for managing water quality in agricultural areas.

  8. Evidence for an early nitrogen isotopic evolution in the solar nebula from volatile analyses of a CAI from the CV3 chondrite NWA 8616

    Science.gov (United States)

    Füri, Evelyn; Chaussidon, Marc; Marty, Bernard

    2015-03-01

    Nitrogen and noble gas (Ne-Ar) abundances and isotope ratios, determined by CO2 laser extraction static mass spectrometry analysis, as well as Al-Mg and O isotope data from secondary ion mass spectrometry (SIMS) analyses, are reported for a type B calcium-aluminum-rich inclusion (CAI) from the CV3 chondrite NWA 8616. The high (26Al/27Al)i ratio of (5.06 ± 0.50) × 10-5 dates the last melting event of the CAI at 39-99+109ka after "time zero", limiting the period during which high-temperature exchanges between the CAI and the nebular gas could have occurred to a very short time interval. Partial isotopic exchange with a 16O-poor reservoir resulted in Δ17O > -5‰ for melilite and anorthite, whereas spinel and Al-Ti-pyroxene retain the inferred original 16O-rich signature of the solar nebula (Δ17O ⩽ -20‰). The low 20Ne/22Ne (⩽0.83) and 36Ar/38Ar (⩽0.75) ratios of the CAI rule out the presence of any trapped planetary or solar noble gases. Cosmogenic 21Ne and 38Ar abundances are consistent with a cosmic ray exposure (CRE) age of ∼14 to 20 Ma, assuming CR fluxes similar to modern ones, without any evidence for pre-irradiation of the CAI before incorporation into the meteorite parent body. Strikingly, the CAI contains 1.4-3.4 ppm N with a δ15N value of +8‰ to +30‰. Even after correcting the measured δ15N values for cosmogenic 15N produced in situ, the CAI is highly enriched in 15N compared to the protosolar nebula (δ15NPSN = -383 ± 8‰; Marty et al., 2011), implying that the CAI-forming region was contaminated by 15N-rich material within the first 0.15 Ma of Solar System history, or, alternatively, that the CAI was ejected into the outer Solar System where it interacted with a 15N-rich reservoir.

  9. Redistribution of REE, Pb and U by supergene weathering studied from in-situ isotopic analyses of the Bangombé natural reactor, Gabon

    Science.gov (United States)

    Kikuchi, M.; Hidaka, H.; Horie, K.; Gauthier-Lafaye, F.

    2007-10-01

    The isotopic analyses of rare earth elements (REE), Pb and U in several kinds of minerals from the clay and black shale layers above the Bangombé natural reactor, Gabon, were performed using a sensitive high-resolution microprobe (SHRIMP) to investigate the migration and retardation processes of fission products released from the reactor. REE isotopic data of the secondary minerals found in clays and black shales show that most of fission products were effectively trapped in the clays and not distributed into the black shales over the clays, which reveals that the clays play an important role in preventing fission products from spreading. Zircon crystals in the clays heterogeneously contain high-U regions (up to 28.3 wt%) with normal 235U/ 238U ratios (=0.00725) and significant amounts of fissiogenic REE, which suggest the occurrence of significant chemical fractionation between REE and U during the dissolution of reactor uraninite and the recrystallization of secondary U minerals. The Pb data suggest that galena grains in the clays were also formed by the mixing of the two components during a recent alteration event, and that a significant amount of Pb was derived from 2.05-Ga-old original uraninite rather than reactor uraninite. The U-Pb systematics of zircon provide chronological information on the old igneous activity associated with the basement rock formation at 2.8 Ga and geochemical evidence of the incomplete mixing of independent Pb and U sources. This result is consistent with previous chronological results in this area.

  10. An ultra-clean technique for accurately analysing Pb isotopes and heavy metals at high spatial resolution in ice cores with sub-pg g(-1) Pb concentrations.

    Science.gov (United States)

    Burn, Laurie J; Rosman, Kevin J R; Candelone, Jean-Pierre; Vallelonga, Paul; Burton, Graeme R; Smith, Andrew M; Morgan, Vin I; Barbante, Carlo; Hong, Sungmin; Boutron, Claude F

    2009-02-23

    Measurements of Pb isotope ratios in ice containing sub-pg g(-1) concentrations are easily compromised by contamination, particularly where limited sample is available. Improved techniques are essential if Antarctic ice cores are to be analysed with sufficient spatial resolution to reveal seasonal variations due to climate. This was achieved here by using stainless steel chisels and saws and strict protocols in an ultra-clean cold room to decontaminate and section ice cores. Artificial ice cores, prepared from high purity water were used to develop and refine the procedures and quantify blanks. Ba and In, two other important elements present at pg g(-1) and fg g(-1) concentrations in Polar ice, were also measured. The final blank amounted to 0.2+/-0.2 pg of Pb with (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of 1.16+/-0.12 and 2.35+/-0.16, respectively, 1.5+/-0.4 pg of Ba and 0.6+/-2.0 fg of In, most of which probably originates from abrasion of the steel saws by the ice. The procedure was demonstrated on a Holocene Antarctic ice core section and was shown to contribute blanks of only approximately 5%, approximately 14% and approximately 0.8% to monthly resolved samples with respective Pb, Ba and In concentrations of 0.12 pg g(-1), 0.3 pg g(-1) and 2.3 fg g(-1). Uncertainties in the Pb isotopic ratio measurements were degraded by only approximately 0.2%.

  11. SIMS analyses of Mg, Cr, and Ni isotopes in primitive meteorites and short-lived radionuclides in the early solar system

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Y.; Huss, G.R.; Leshin, L.A

    2004-06-15

    SIMS analyses of {sup 26}Al-{sup 26}Mg, {sup 60}Fe-{sup 60}Ni, and {sup 53}Mn-{sup 53}Cr systems in unequilibrated enstatite chondrites provide evidence for the former existence of {sup 26}Al, {sup 60}Fe, and {sup 53}Mn in this highly reduced meteorite group, suggesting the widespread of these short-lived radionuclides in the early solar system. Calcium-aluminum-rich inclusions and Al-rich chondrules in enstatite chondrites show {sup 26}Al-{sup 26}Mg characteristics similar to their counterparts in other types of chondrites. Assuming its homogenous distribution, fine-scale {sup 26}Al relative chronology can be obtained for different components in meteorites. Well-defined isochrons yield initial {sup 60}Fe/{sup 56}Fe ratios of (0.3-1)x10{sup -6} in sulfides from enstatite chondrites. The former presence of {sup 60}Fe suggests a stellar source and its possible high abundance points to a supernova origin. {sup 26}Al and {sup 60}Fe could be important heat sources for the early planetary processes. The large variations of initial {sup 60}Fe/{sup 56}Fe and {sup 53}Mn/{sup 55}Mn ratios and the discordance between {sup 60}Fe-{sup 60}Ni and {sup 53}Mn-{sup 53}Cr systems observed in sulfides indicate later disturbance of the two isotopic systems, and therefore, bear no strict chronological significance. SIMS isotopic analysis can be utilized to attain important information about the early evolution of the solar system.

  12. Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: a freshwater bivalve study.

    Science.gov (United States)

    Company, R; Serafim, A; Lopes, B; Cravo, A; Shepherd, T J; Pearson, G; Bebianno, M J

    2008-11-01

    Lead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, delta-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.

  13. Anthropogenic and natural lead isotopes in Fe-hydroxides and Fe-sulphates in a watershed associated with arsenic-enriched groundwater, Maine, USA

    Science.gov (United States)

    Ayuso, Robert A.; Foley, Nora K.

    2008-01-01

    A survey of the natural and anthropogenic sources of lead contributing to secondary minerals in sulphidic schists associated with arsenic-enriched groundwater in Coastal Maine shows that the most likely source is natural Pb, particularly from coexisting sulphide minerals. The secondary minerals also reflect notable contributions from anthropogenic Pb. The Pb isotopes establish pathways by which Pb, and by inference As, could have been transported from As-bearing minerals (arsenian pyrite, arsenopyrite, lollingite, orpiment, arsenic oxide and others), via sulphide oxidation or carbonation reactions into multiple generations of secondary minerals (goethite, hematite, jarosite, natrojarosite and others). Lead isotopic compositions of the sulphides and secondary minerals determined by thermal ionization mass spectrometry (n=53) range widely. Lead and As contents of the sulphides and secondary minerals overlap, and are generally positively correlated. Pyrite, the dominant sulphide in sulphidic schists associated with As-enriched groundwater in Coastal Maine, has values of 206Pb/204Pb from 18.186 to 18.391, 207Pb/204Pb from 15.617 to 15.657, 208Pb/204Pb from 38.052 to 38.210, 206Pb/207Pb from c. 1.1625 to 1.1760 and 208Pb/207Pb from c. 2.4276 to 2.4394. Mixtures of Fe-hydroxide and oxide minerals (predominantly goethite and hematite) and secondary Fe-sulphate minerals (jarosite, natrojarosite, rozenite and melanterite) in the sulphidic schists have overlapping but generally higher values of 206Pb/204Pb from 18.495 to 19.747 (one sample at 21.495), 207Pb/204Pb from 15.595 to 15.722 (one sample at 15.839), 208Pb/204Pb from 38.186 to 39.162,206Pb/207Pb from c.1.1860 to 1.2575 (one sample at 1.3855) and 208Pb/207Pb from c. 2.4441 to 2.4865 than the sulphides. Sulphides from Zn-Pb metal mines are somewhat less radiogenic than sulphides from the schists. Other sulphides (mostly pyrite) associated with pegmatites and granitic rocks are heterogeneous and more

  14. Identification of Novel Drug Targets and Lead Compounds for Advanced Prostate Cancer through Genomic and Cheminformatic Analyses

    Science.gov (United States)

    2015-08-01

    Med Res Rev 2013;33:1081–118. [18] Guo W, Burris TP, Zhang YH, Huang BL, Mason J, Copeland KC, et al. Genomic sequence of the DAX1 gene: an orphan...191] Maran RR, Thomas A, Roth M, Sheng Z, Esterly N, Pinson D, et al. Farnesoid X receptor deficiency in mice leads to increased intestinal epithelial

  15. Development of SI-traceable C-peptide certified reference material NMIJ CRM 6901-a using isotope-dilution mass spectrometry-based amino acid analyses.

    Science.gov (United States)

    Kinumi, Tomoya; Goto, Mari; Eyama, Sakae; Kato, Megumi; Kasama, Takeshi; Takatsu, Akiko

    2012-07-01

    A certified reference material (CRM) is a higher-order calibration material used to enable a traceable analysis. This paper describes the development of a C-peptide CRM (NMIJ CRM 6901-a) by the National Metrology Institute of Japan using two independent methods for amino acid analysis based on isotope-dilution mass spectrometry. C-peptide is a 31-mer peptide that is utilized for the evaluation of β-cell function in the pancreas in clinical testing. This CRM is a lyophilized synthetic peptide having the human C-peptide sequence, and contains deamidated and pyroglutamylated forms of C-peptide. By adding water (1.00 ± 0.01) g into the vial containing the CRM, the C-peptide solution in 10 mM phosphate buffer saline (pH 6.6) is reconstituted. We assigned two certified values that represent the concentrations of total C-peptide (mixture of C-peptide, deamidated C-peptide, and pyroglutamylated C-peptide) and C-peptide. The certified concentration of total C-peptide was determined by two amino acid analyses using pre-column derivatization liquid chromatography-mass spectrometry and hydrophilic chromatography-mass spectrometry following acid hydrolysis. The certified concentration of C-peptide was determined by multiplying the concentration of total C-peptide by the ratio of the relative area of C-peptide to that of the total C-peptide measured by liquid chromatography. The certified value of C-peptide (80.7 ± 5.0) mg/L represents the concentration of the specific entity of C-peptide; on the other hand, the certified value of total C-peptide, (81.7 ± 5.1) mg/L can be used for analyses that does not differentiate deamidated and pyroglutamylated C-peptide from C-peptide itself, such as amino acid analyses and immunochemical assays.

  16. Energy scenarios for Germany. A critical analysis of the 2011 Lead Study; Energieszenarien fuer Deutschland. Eine kritische Analyse der Leitstudie 2011

    Energy Technology Data Exchange (ETDEWEB)

    Hake, Juergen-Friedrich; Hansen, Patrick; Kronenberg, Tobias; Pesch, Thiemo [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energie- und Klimaforschung, Systemforschung und Technologische Entwicklung (IEK-STE)

    2012-06-15

    A multitude of energy scenarios has evolved over the past years for the purpose of analysing future developments of the German energy supply system. These scenarios differ markedly in their goals and methods. This article presents an analysis method for classifying and comparing these scenarios and then proceeds to apply the method to the current ''Lead Study''.

  17. Controls on the long term earthquake behavior of an intraplate fault revealed by U-Th and stable isotope analyses of syntectonic calcite veins

    Science.gov (United States)

    Williams, Randolph; Goodwin, Laurel; Sharp, Warren; Mozley, Peter

    2017-04-01

    U-Th dates on calcite precipitated in coseismic extension fractures in the Loma Blanca normal fault zone, Rio Grande rift, NM, USA, constrain earthquake recurrence intervals from 150-565 ka. This is the longest direct record of seismicity documented for a fault in any tectonic environment. Combined U-Th and stable isotope analyses of these calcite veins define 13 distinct earthquake events. These data show that for more than 400 ka the Loma Blanca fault produced earthquakes with a mean recurrence interval of 40 ± 7 ka. The coefficient of variation for these events is 0.40, indicating strongly periodic seismicity consistent with a time-dependent model of earthquake recurrence. Stochastic statistical analyses further validate the inference that earthquake behavior on the Loma Blanca was time-dependent. The time-dependent nature of these earthquakes suggests that the seismic cycle was fundamentally controlled by a stress renewal process. However, this periodic cycle was punctuated by an episode of clustered seismicity at 430 ka. Recurrence intervals within the earthquake cluster were as low as 5-11 ka. Breccia veins formed during this episode exhibit carbon isotope signatures consistent with having formed through pronounced degassing of a CO2 charged brine during post-failure, fault-localized fluid migration. The 40 ka periodicity of the long-term earthquake record of the Loma Blanca fault is similar in magnitude to recurrence intervals documented through paleoseismic studies of other normal faults in the Rio Grande rift and Basin and Range Province. We propose that it represents a background rate of failure in intraplate extension. The short-term, clustered seismicity that occurred on the fault records an interruption of the stress renewal process, likely by elevated fluid pressure in deeper structural levels of the fault, consistent with fault-valve behavior. The relationship between recurrence interval and inferred fluid degassing suggests that pore fluid pressure

  18. Assessment of heavy metal pollution in sediments from Xiangjiang River (China) using sequential extraction and lead isotope analysis

    Institute of Scientific and Technical Information of China (English)

    蒋博峰; 孙卫玲

    2014-01-01

    The heavy metal (such as Cr, Ni, Cu, Cd, Pb, and Zn) concentration, speciation, and pollution source in 43 sediment samples from the Xiangjiang River were investigated using sequential extraction combined with Pb isotope analysis. Cu, Cd, Pb, and Zn concentrations are higher than their background values, while Cr and Ni concentrations are close to those. Sequential extraction demonstrates that heavy metals have different fractions, showing different bioavailabilities. Thew(206Pb)/w(207Pb) ratio increases with decreasing bioavailability in the order of exchangeable

  19. A century long sedimentary record of anthropogenic lead (Pb), Pb isotopes and other trace metals in Singapore.

    Science.gov (United States)

    Chen, Mengli; Boyle, Edward A; Switzer, Adam D; Gouramanis, Chris

    2016-06-01

    Reconstructing the history of metal deposition in Singapore lake sediments contributes to understanding the anthropogenic and natural metal deposition in the data-sparse Southeast Asia. To this end, we present a sedimentary record of Pb, Pb isotopes and eleven other metals (Ag, As, Ba, Cd, Co, Cr, Cu, Ni, Tl, U and Zn) from a well-dated sediment core collected near the depocenter of MacRitchie Reservoir in central Singapore. Before the 1900s, the sedimentary Pb concentration was less than 2 mg/kg for both soil and sediment, with a corresponding (206)Pb/(207)Pb of ∼1.20. The Pb concentration increased to 55 mg/kg in the 1990s, and correspondingly the (206)Pb/(207)Pb decreased to less than 1.14. The (206)Pb/(207)Pb in the core top sediment is concordant with the (206)Pb/(207)Pb signal of aerosols in Singapore and other Southeast Asian cities, suggesting that Pb in the reservoir sediment was mainly from atmospheric deposition. Using the Pb concentration in the topmost layer of sediment, the estimated atmospheric Pb flux in Singapore today is ∼1.6 × 10(-2) g/m(2) yr. The concentrations of eleven other metals preserved in the sediment were also determined. A principal component analysis showed that most of the metals exhibit an increasing trend towards 1990s with a local concentration peak in the mid-20(th) century.

  20. Lead isotope ratios in lichen samples evaluated by ICP-ToF-MS to assess possible atmospheric pollution sources in Havana, Cuba.

    Science.gov (United States)

    Alvarez, Alfredo Montero; Estévez Alvarez, Juan R; do Nascimento, Clístenes Williams Araújo; González, Iván Pupo; Rizo, Oscar Díaz; Carzola, Lázaro Lima; Torres, Roberto Ayllón; Pascual, Jorge Gómez

    2017-01-01

    Epiphytic lichens, collected from 119 sampling sites grown over "Roistonea Royal Palm" trees, were used to assess the spatial distribution pattern of lead (Pb) and identify possible pollution sources in Havana (Cuba). Lead concentrations in lichens and topsoils were determined by flame atomic absorption spectrophotometry and inductively coupled plasma (ICP) atomic emission spectrometry, respectively, while Pb in crude oils and gasoline samples were measured by ICP-time of flight mass spectrometry (ICP-ToF-MS). Lead isotopic ratios measurements for lichens, soils, and crude oils were obtained by ICP-ToF-MS. We found that enrichment factors (EF) reflected a moderate contamination for 71% of the samples (EF > 10). The (206)Pb/(207)Pb ratio values for lichens ranged from 1.17 to 1.20 and were a mixture of natural radiogenic and industrial activities (e.g., crude oils and fire plants). The low concentration of Pb found in gasoline (<7.0 μg L(-1)) confirms the official statement that leaded gasoline is no longer used in Cuba.

  1. Pre-Hercynian hydrothermalism in South Iberia: lead isotope geochemistry constraints; Hydrothermalisme ante-hercynien en Sud-Iberie: apport de la geochimie isotopique du plomb

    Energy Technology Data Exchange (ETDEWEB)

    Marcoux, E.; Onezime, J. [Orleans Univ., Institut des Sciences de la Terre d' Orleans, 45 (France); Pascual, E. [Universite d' Huelva, Dept. de Geologia y MIneria, Huelva (Spain)

    2002-04-01

    Lead isotope study has been performed on massive sulphide deposits of Ossa-Morena and Aracena Belt (South Iberia). Results suggest the existence of at least two ancient hydrothermal events. The first one, Upper Brioverian in age ({approx}600-570 Ma), gave birth to Maria-Luisa and Puebla de la Reina massive sulphide deposits; it thus confirms the existence of a Cadomian orogen in South Iberia. Isotopic compositions indicate a local contribution of mantle-derived material (Maria Luisa mine), confirming the presence of ancient oceanic crust in Aracena Belt. This mineralizing event seems to extend till the Armorican Massif. The second episode, Eo-Hercynian in age ({approx}400-350 Ma) has allowed genesis of massive sulphide deposits of la Nava Paredon and Aguas Blancas, and could be coeval with the emplacement of South-Iberian massive sulphide ore deposits in the neighbouring South-Portuguese Zone. A more continental crustal source for later ore deposits could explain the much more important metal accumulation in this zone. (authors)

  2. Contamination limits for real and personal property. Progress report, July--December 1975. [Plutonium and lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Healy, J.W.; Wenzel, W.J.

    1976-05-01

    Studies of surface contamination continued with an attempt to apply previous concepts. Revision of the proposed limit for plutonium in soils was started with major efforts on wind resuspension and the use of data on environmental lead to estimate intake by children.

  3. Trophic ecology of two cold-water coral species from the Mediterranean Sea revealed by lipid biomarkers and compound-specific isotope analyses

    Science.gov (United States)

    Naumann, Malik S.; Tolosa, Imma; Taviani, Marco; Grover, Renaud; Ferrier-Pagès, Christine

    2015-12-01

    Scleractinian cold-water corals (CWC) act as key ecosystem engineers in deep-sea reef environments worldwide. However, our current understanding of their trophic ecology is still limited, particularly in understudied temperate oceanic regions such as the Mediterranean Sea. Hence, this study investigated the trophic ecology of the CWC Desmophyllum dianthus and Madrepora oculata by employing lipid biomarker techniques and compound-specific isotope analyses on coral tissues, suspended particulate organic matter (sPOM), and surface sediment sampled in a Mediterranean CWC habitat. CWC exhibited high contents of poly- and monounsaturated fatty acids (FA) (≥49 and 32 % of FA, respectively) and cholesterol (≥67 % of sterols), while sPOM and sediment samples were enriched in saturated FA (≥44 % of FA) and sitosterol (≥35 % of sterols). CWC contained some rare very long-chained polyunsaturated FA (>C22) and ergosterol absent in sPOM and sediment samples. Our results indicate that Mediterranean CWC mainly consume living food items, rather than detrital sPOM or resuspended sediment, and provide evidence for preferred feeding on omnivorous and carnivorous zooplankton. Overall, these findings provide new insights to the trophic ecology of two common CWC from the Mediterranean Sea.

  4. Soils Developed from Different Volcanic Rocks from the Fernando de Noronha Island: Rare-Earth Element Patterns and Isotopic Lead Composition

    Directory of Open Access Journals (Sweden)

    Sonia Maria Barros de Oliveira

    2011-12-01

    Full Text Available This study examines the infl uence of pedogenesis on the distribution of rare earth elements in soils derived fromdifferent rock types and formed under tropical humid climate, as well as the possible contribution of airborne Pb to thesesoils. We studied 5 soil profi les developed from different volcanic rocks cropping out in the Fernando de Noronha island.Results show that in the course of weathering, the soils were enriched in REE. The REE patterns of the soils are similarto those of the parent material, except for a slight HREE enrichment. Lead-isotope data indicate the presence of a nonradiogenicanthropogenic component in the upper horizons of the soil profi les.

  5. Precambrian ophiolites of Arabia; a summary of geologic settings, U-Pb geochronology, lead isotope characteristics, and implications for microplate accretion, Kingdom of Saudi Arabia

    Science.gov (United States)

    Pallister, John S.; Stacey, J.S.; Fischer, L.B.; Premo, W.R.

    1988-01-01

    Disrupted ophiolites occur in linear belts as much as 900 km long between micro plates that collided during the late Proterozoic to form the Arabian Shield. The U-Pb zircon ages and lead-isotope data from these ophiolitic rocks help constrain the history of accretion of the Arabian Shield and thereby contribute to the definition of its microplates and terranes. Microplates of the central and western Arabian Shield are generally thought to represent intra-oceanic island arcs that range in age from about 900 Ma to 640 Ma; however, a region of the eastern Arabian Shield contains rocks of early Proterozoic age and may represent an exotic continental fragment entrained between the arc complexes.

  6. 铅稳定同位素示踪在铅污染研究中的应用%Application of stable lead isotopes to trace the lead pollution

    Institute of Scientific and Technical Information of China (English)

    常向阳; 付善明; 陈南; 吴丽琴; 毛利红; 王道芳; 肖方; 朱炳泉

    2012-01-01

    The history of human civilization is also the annals of lead pollution. The wide use of lead results in the lead pollution of atmosphere, water and surface sediments globally. Lots of harm issues to human health draw our attention to the lead pollution. Due to various sources, it is a complicated problem how to identify the source of the lead pollution and evaluate the extent of the lead pollution. There are lots of evidence indicating that the ratios of lead isotopes could trace the sources of lead pollution effectively and estimate trace out of the moving path of the industrial waste in large scale. With the use of lead-free gasoline popularly, the lead pollu- tion from the gasoline and food becomes less and less than before, but that from the paint should be paid more attention to.%人类文明史也是一部铅污染史,铅的广泛使用产生了全球性的大气、水源和地表沉积物的铅污染.铅污染造成对人体健康的危害问题已引起社会的广泛关注.铅的污染来源是多方面的,对于如何来定量确定污染源和评估污染程度仍然是一个复杂的问题.铅同位素组成特征可以有效地指示污染的来源,并可有效地评价大尺度范围内工业污染物的运移路径.随着无铅汽油的广泛使用,来源于汽油和食物中的铅污染在减弱,但来源于涂料和油漆中的铅污染越来越受到关注.

  7. High-resolution quadruple sulfur isotope analyses of 3.2 Ga pyrite from the Barberton Greenstone Belt in South Africa reveal distinct environmental controls on sulfide isotopic arrays

    NARCIS (Netherlands)

    Roerdink, D.L.; Mason, P.R.D.; Whitehouse, M.J.; Reimer, T.

    2013-01-01

    Multiple sulfur isotopes in Paleoarchean pyrite record valuable information on atmospheric processes and emerging microbial activity in the early sulfur cycle. Here, we report quadruple sulfur isotope data (32S, 33S, 34S, 36S) analyzed by secondary ion mass spectrometry from pyrite in a 3.26–3.23 Ga

  8. Application of inductively coupled plasma quadrupole mass spectrometry for the determination of monazite ages by lead isotope ratios

    OpenAIRE

    Godoy,José Marcus; Godoy,Maria Luiza D. P; Aronne,Cláudia C.

    2007-01-01

    In order to evaluate the applicability of inductively coupled plasma quadrupole mass spectrometry to the determination of Pb/Pb, U/Pb and Th/Pb ages of monazite, studies were carried out initially applying lead atom ratio reference standards (NIST SRM 981 and 982). Further, the optimized methodology was applied to monazite sands from three different sites, Sugar Loaf Hill (Rio de Janeiro city), Buena (Rio de Janeiro state) and Black Sands Beach (Guarapari, Espirito Santo state); the obtained ...

  9. Leaching Behavior of Slags from AN Old Lead Smelter in Chihuahua, Mexico: Metals, Chlorides, Nitrates, Sulfates and Tds Analyses

    Science.gov (United States)

    Espejel-Garcia, D.; Wenglas-Lara, G.; Villalobos-Aragon, A.; Espejel-Garcia, V. V.

    2013-05-01

    Waste materials (such as, smelter slags, waste glass, tires, plastics, rubbish, ashes, etc.), have a large potential to substitute natural materials, reducing costs, especially for the construction industry. Smelter slags are resistant and have better compression strength values in comparison to natural aggregates, and generally are far beyond of what the standard ratios need to qualify a material as a good one for construction. But this material has a big problem within it: the existence of toxic elements and compounds in high concentrations, which means that water and soil contamination can be present after water infiltrates through this material; so we perform leaching experiments to characterize and measure the possible contamination under controlled conditions. To perform the slags-leaching experiments, we used an EA-NEN-7375-2004 tank test standard from Netherlands. This test was selected because to our knowledge it is the only one which allows the use of coarse material, as the one utilized in construction. The leaching experiments sampling was performed at different times: 6, 24, 168 and 360 hours, to compare the leachate concentration at the two different pH's values (5 and 8) selected to simulate real conditions. For the leaching experiments, the slags were mixed with natural road base material (gravel-sands from volcanic rocks) at different proportions of 30% and 50%. In order to understand the slags' leaching behavior, other experiments were carried out with the pure material, for both (slags and natural aggregates). After analyses by ICP-OES , the slags from this smelter in Chihuahua contain Pb (0.5 - 4 wt.%), Zn (15-35 wt.%) and As (0.6 wt.%), as well such as: bicarbonates, chlorides, nitrates, sulfates, Mg, K, Na, Ca and TDS. Based on the results of the leaching analyses, via atomic absorption technique, we conclude that Pb and As concentrations are provided by the slags, meanwhile, the bicarbonates, chlorides, Na and Ca are contributed by the road

  10. Isotopic composition ([delta][sup 18]O) of the upper stalagmitic floor of Lazaret cave at Nice. Analyse de la composition isotopique ([delta][sup 18]O) du plancher stalagmitique superieur de la grotte du Lazaret a Nice

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, L.; Lumley, H. de; Bahain, J.J.; Falgueres, C. (Institut de Paleontologie, 75 - Paris (France)); Robert, F. (Museum National d' Histoire Naturelle, 75 - Paris (France))

    1994-03-17

    Radiochronological and mineralogical studies of the stalagmitic floor 'Ensemble E' of the Lazaret cave at Nice revealed that its formation has been continuous during the climatic period corresponding to 'stage 5'. In addition, biochemical analyses of this floor showed that the crystals behave as a closed system with respect to organic compounds (sterols). Oxygen isotopic compositions have registered variations which are qualitatively in agreement with those ascribed to stage 5. Therefore, these oxygen isotopic variations may be used as an independent geochemical chronometer. (authors). 15 refs.

  11. Combining lead isotopes and cluster analysis to distinguish the Guarani and Serra Geral Aquifer Systems and contaminated waters in a highly industrialized area in Southern Brazil.

    Science.gov (United States)

    Kuhn, Isadora Aumond; Roisenberg, Ari

    2017-10-01

    The Rio dos Sinos Watershed area is located at the Middle-West region of the Rio Grande do Sul State, Southern Brazil, along thirty two municipalities and affecting 1.5 million inhabitants and many important industrial centers. Three main aquifers are recognized in the study area: the unconfined-fractured Serra Geral Aquifer System, the porous Guarani Aquifer System, and the Permian Aquitard. This study aims to understand groundwater, surface water and human activity interactions in the Rio dos Sinos Watershed, evaluating the application of stable lead isotopic ratios analyzed for this propose. Thirty six groundwater samples, 8 surface water samples and 5 liquid effluents of tanneries and landfills samples were measured using a Thermal Ionization Mass Spectrometer Thermo-Finnigan and a Neptune Multi-Collector Inductively Coupled Plasma Mass Spectrometer. Groundwater isotopic ratios have a wider range compared to the surface water, with less radiogenic averages (208)Pb/(204)Pb = 38.1837 vs 38.4050 (standard deviation = 0.2921 vs 0.1343) and (206)Pb/(204)Pb = 18.2947 vs 18.4766 (standard deviation = 0.2215 vs 0.1059), respectively. Industrial liquid effluents (tanneries and industrial landfill) have averages (208)Pb/(204)Pb = 38.1956 and (206)Pb/(204)Pb = 18.3169, distinct from effluent samples of domestic sanitary landfill (averages (208)Pb/(204)Pb = 38.2353 and (206)Pb/(204)Pb = 18.6607). Hierarchical cluster analysis led to distinguish six groups of groundwater, representing the three aquifers that occur in the area, two clusters suggesting groundwater mixtures and one demonstrating a highly contaminated groundwater. By analyzing the cluster results and wells' stratigraphic profiles it was possible to distinguish the different aquifers in the area. The Serra Geral Aquifer System has (206)Pb/(204)Pb ratios between 18.4718 and 18.7089; (207)Pb/(204)Pb between 15.6692 and 15.6777; (208)Pb/(204)Pb between 38.6826 and 38.7616; (207)Pb/(206)Pb between 0

  12. The isotopic composition of ore lead of the Creede mining district and vicinity, San Juan Mountains, Colorado: Text of a talk presented at the San Juan Mountains symposium to honor Thomas A. Steven; Rocky Mountain Section meeting of the Geological Society of America, May 2, 1987, Boulder, Colorado

    Science.gov (United States)

    Foley, N.K.; Barton, P.B.; Bethke, P.M.; Doe, B.R.

    1988-01-01

    Galenas from the major Creede veins and their northern extensions are remarkably homogeneous in Pb-isotopic composition and are too radiogenic to have been derived from any magma comparable in composition to the principal volcanic rocks. This pattern was identified by Doe et al. in 1979 who proposed that the lead was derived from the Precambrian basement. The homogeneity of the ore leads, however, requires a uniform reservoir; an unlikely prospect for lead from the Precambrian basement. We report on 16 new analyses of geographically and paragenetically dispersed galenas from the Creede district and other areas as far as 11 km to the north. The lead values range from 18.972 to 19.060 for 206Pb/204Pb, from 15.591 to 15.671 for 207Pb/204Pb, and from 37.781 to 37.921 for 208Pb/204Pb. These ranges overlap those previously reported for the main ore zone.

  13. Lead fluxes and 206Pb/207Pb isotope ratios in rime and snow collected at remote mountain-top locations (Czech Republic, Central Europe): Patterns and sources

    Science.gov (United States)

    Cimova, Nikoleta; Novak, Martin; Chrastny, Vladislav; Curik, Jan; Veselovsky, Frantisek; Blaha, Vladimir; Prechova, Eva; Pasava, Jan; Houskova, Marie; Bohdalkova, Leona; Stepanova, Marketa; Mikova, Jitka; Krachler, Michael; Komarek, Arnost

    2016-10-01

    During three winter seasons (2009-2011), Pb concentrations were measured in precipitation at 10 high-elevation sites in the Czech Republic, close to the borders with Austria, Germany, Poland, and Slovakia. Soluble and insoluble Pb forms were quantified in snow (vertical deposition), and rime (horizontal deposition). The objective was to compare Pb input fluxes into ecosystems via vertical and horizontal deposition, and to identify the residual Pb pollution sources in an era of rapidly decreasing industrial pollution. Lead soluble in diluted HNO3 made up 96% of total Pb deposition, with the remaining 4% Pb bound mainly in silicates. Three times higher concentrations of soluble Pb in rime than in snow, and 2.5 times higher concentrations of insoluble Pb in rime than in snow were associated with slightly different Pb isotope ratios. On average, the 206Pb/207Pb ratios in rime were higher than those in snow. Higher mean 206Pb/207Pb ratios of insoluble Pb (1.175) than in soluble Pb (1.165) may indicate an increasing role of geogenic Pb in recent atmospheric deposition. A distinct reversal to more radiogenic 206Pb/207Pb ratios in snow and rime in 2010, compared to literature data from rain-fed Sphagnum peatlands (1800-2000 A.D.), documented a recent decrease in anthropogenic Pb in the atmosphere of Central Europe. Since the early 1980s, Pb concentrations in snow decreased 18 times in the rural south of the Czech Republic, but only twice in the industrial north of the Czech Republic. Isotope signatures indicated that Pb in today's atmospheric deposition is mainly derived from Mesozoic ores mined/processed in Poland and coal combustion in the Czech Republic and Poland.

  14. Predicting origins of passerines migrating through Canadian migration monitoring stations using stable-hydrogen isotope analyses of feathers: a new tool for bird conservation

    Directory of Open Access Journals (Sweden)

    Keith A. Hobson

    2015-06-01

    Full Text Available The Canadian Migration Monitoring Network (CMMN consists of standardized observation and migration count stations located largely along Canada's southern border. A major purpose of CMMN is to detect population trends of migratory passerines that breed primarily in the boreal forest and are otherwise poorly monitored by the North American Breeding Bird Survey (BBS. A primary limitation of this approach to monitoring is that it is currently not clear which geographic regions of the boreal forest are represented by the trends generated for each bird species at each station or group of stations. Such information on "catchment areas" for CMMN will greatly enhance their value in contributing to understanding causes of population trends, as well as facilitating joint trend analysis for stations with similar catchments. It is now well established that naturally occurring concentrations of deuterium in feathers grown in North America can provide information on their approximate geographic origins, especially latitude. We used stable hydrogen isotope analyses of feathers (δ²Hf from 15 species intercepted at 22 CMMN stations to assign approximate origins to populations moving through stations or groups of stations. We further constrained the potential catchment areas using prior information on potential longitudinal origins based upon bird migration trajectories predicted from band recovery data and known breeding distributions. We detected several cases of differences in catchment area of species passing through sites, and between seasons within species. We discuss the importance of our findings, and future directions for using this approach to assist conservation of migratory birds at continental scales.

  15. Characterization of cocoa butter and cocoa butter equivalents by bulk and molecular carbon isotope analyses: implications for vegetable fat quantification in chocolate.

    Science.gov (United States)

    Spangenberg, J E; Dionisi, F

    2001-09-01

    The fatty acids from cocoa butters of different origins, varieties, and suppliers and a number of cocoa butter equivalents (Illexao 30-61, Illexao 30-71, Illexao 30-96, Choclin, Coberine, Chocosine-Illipé, Chocosine-Shea, Shokao, Akomax, Akonord, and Ertina) were investigated by bulk stable carbon isotope analysis and compound specific isotope analysis. The interpretation is based on principal component analysis combining the fatty acid concentrations and the bulk and molecular isotopic data. The scatterplot of the two first principal components allowed detection of the addition of vegetable fats to cocoa butters. Enrichment in heavy carbon isotope ((13)C) of the bulk cocoa butter and of the individual fatty acids is related to mixing with other vegetable fats and possibly to thermally or oxidatively induced degradation during processing (e.g., drying and roasting of the cocoa beans or deodorization of the pressed fat) or storage. The feasibility of the analytical approach for authenticity assessment is discussed.

  16. Combined U Pb and Hf isotope LA-(MC-)ICP-MS analyses of detrital zircons: Comparison with SHRIMP and new constraints for the provenance and age of an Armorican metasediment in Central Germany

    Science.gov (United States)

    Gerdes, Axel; Zeh, Armin

    2006-09-01

    Uranium-lead ages obtained by LA-ICP-MS analyses of zircon cores from a high-grade Armorican metasediment from the Mid-German Crystalline Rise, Central Germany, yield results which are identical to, but more precise than those previously obtained by SHRIMP dating. This is mainly due to the fact that SHRIMP analyses are more sensitive than LA-ICP-MS analyses to common Pb contamination on the surface of the grain mount. The new U-Pb ages, in combination with in-situ Hf isotope analyses of zircon, provide the first evidence that detrital zircons within Armorican sediments crystallized in both juvenile and evolved magmatic rocks during the Archaean at 2.7-2.9 Ga, the Palaeoproterozoic at 1.8-2.1 Ga, and the Neoproterozoic/Early Palaeozoic at 500-720 Ma. In addition, zircons were formed at ca. 1.0 Ga by remelting of Palaeoproterozoic crust during the Grenville orogeny. The U-Pb dataset shows an age gap between 1.8 and 1.0 Ga, which is characteristic of Armorican sediments, and indicates that the metasediment protolith is younger than Late Cambrian. In addition, the data support previous conclusions that sediments constituting the Armorican terrane assemblage were derived from three crustal sources. Dominant sources were the Avalonian-Cadomian belt (ca. 45%), situated at the northern margin of Gondwana during the Neoproterozoic, and the West-African and/or eastern Amazonian cratons (ca. 50%). The Grenville belt was a minor source (< 5%). Variation of ɛHf( t) values of the Neoproterozoic/Early Paleozoic zircons indicates two periods of increased juvenile magma formation, one at 595-575 Ma and a second at 515-500 Ma. The older event is coeval with the formation of the Avalonian-Cadomian magmatic arc, whereas the younger event can be related to the break-up of the northern Gondwana margin in Cambrian/Ordovician times. In between, at around 545 Ma, only recycling of older crustal material took place.

  17. Uranium-lead isotope systematics and apparent ages of zircons and other minerals in precambrian granitic rocks, Granite Mountains, Wyoming

    Science.gov (United States)

    Ludwig, K. R.; Stuckless, J.S.

    1978-01-01

    Zircon suites from the two main types of granite in the Granite Mountains, Wyoming, yielded concordia-intercept ages of 2,640??20 m.y. for a red, foliated granite (granite of Long Creek Mountain) and 2,595??40 m.y. for the much larger mass of the granite of Lankin Dome. These ages are statistically distinct (40??20 m.y. difference) and are consistent with observed chemical and textural differences. The lower intercepts of the zircon chords of 50??40 and 100+ 75 m.y. for the granite of Long Creek Mountain and granite of Lankin Dome, respectively, are not consistent with reasonable continuous diffusion lead-loss curves but do correspond well with the known (Laramide) time of uplift of the rocks. Epidote, zircon, and apatite from silicified and epidotized zones in the granites all record at least one postcrystallization disturbance in addition to the Laramide event and do not define a unique age of silicification and epidotization. The lower limit of ???2,500 m.y. provided by the least disturbed epidote, however, suggests that these rocks were probably formed by deuteric processes shortly after emplacement of the granite of the Lankin Dome. The earlier of the two disturbances that affected the minerals of the silicified-epidotized rock can be bracketed between 1,350 and 2,240 m.y. ago and is probably the same event that lowered mineral K-Ar and ages in the region. Zircon suites from both types of granite show well-defined linear correlations among U content, common-Pb content, and degree of discordance. One of the zircon suites has an extremely high common-Pb content (up to 180 ppm) and exhibits a component of radiogenic-Pb loss that is apparently unrelated to radiation damage. ?? 1978 Springer-Verlag.

  18. Origin of lead in eight Central European peat bogs determined from isotope ratios, strengths, and operation times of regional pollution sources.

    Science.gov (United States)

    Novák, Martin; Emmanuel, Simon; Vile, Melanie A; Erel, Yigal; Véron, Alain; Paces, Tomás; Wieder, R Kelman; Vanecek, Mirko; Stepánová, Markéta; Brízová, Eva; Hovorka, Jan

    2003-02-01

    Lead originating from coal burning, gasoline burning, and ore smelting was identified in 210Pb-dated profiles through eight peat bogs distributed over an area of 60,000 km2. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering with Germany, Austria, and Poland. Basal peat 14C-dated at 11,000 years BP had a relatively high 206Pb/207Pb ratio (1.193). Peat deposited around 1800 AD had a lower 206Pb/207Pb ratio of 1.168-1.178, indicating that environmental lead in Central Europe had been largely affected by human activity (smelting) even before the beginning of the Industrial Revolution. Five of the sites exhibited a nearly constant 206Pb/207Pb ratio (1.175) throughout the 19th century, resembling the "anthropogenic baseline" described in Northern Europe (1.17). At all sites, the 206Pb/207Pb ratio of peat decreased at least until 1980; at four sites, a reversal to more radiogenic values (higher 206Pb/207Pb), typical of easing pollution, was observed in the following decade (1980-1990). A time series of annual outputs for 14 different mining districts dispersing lead into the environment has been constructed for the past 200 years. The production of Ag-Pb, coal, and leaded gasoline peaked in 1900, 1980, and 1980, respectively. In contrast to other European countries, no peak in annual Pb accumulation rates was found in 1900, the year of maximum ore smelting. The highest annual Pb accumulation rates in peat were consistent with the highest Pb emission rates from coal-fired power plants and traffic (1980). Although maximum coal and gasoline production coincided in time, their isotope ratios were unique. The mean measured 206Pb/207Pb ratios of local coal, ores, and gasoline were 1.19, 1.16, and 1.11, respectively. A considerable proportion of coal emissions, relative to gasoline emisions, was responsible for the higher 206Pb/207Pb ratios in the recent atmosphere (1.15) compared to Western Europe (1.10). As in West European

  19. Isotope analysis of lead pollution sources in wheat kernel%小麦籽粒铅污染来源的同位素解析研究

    Institute of Scientific and Technical Information of China (English)

    赵多勇; 魏益民; 魏帅; 郭波莉; 蔡先峰; 吴小胜

    2012-01-01

    以中国西北地区某工业区为研究区域,采集大气降尘、耕层土壤样品(0~20 cm),及对应农田位置的小麦籽粒样品,用电感耦合等离子质谱( ICP-MS)测定铅元素质量比及铅同位素比率值.运用普通块克里金法(Ordinary Kriging)预测大气铅沉降通量分布、耕层土壤和小麦籽粒铅质量比空间分布;结合二元混合模型计算各污染源对小麦籽粒铅质量比的贡献率.结果表明:1)耕层土壤铅质量比范围为21.8~40.0 mg/kg,平均值为27.1 mg/kg,高于当地土壤背景值(21.4 mg/kg),说明耕层土壤受到一定程度的污染.2)研究区域小麦籽粒铅质量比范围为0.269~0.768 mg/kg,平均值为0.430 mg/kg,超标率达100%.3)大气降尘和耕层土壤对小麦籽粒铅质量比的贡献率分别为90%~99%和1%~10%.通过研究耕层土壤和小麦铅污染的范围及程度,探讨小麦籽粒铅污染的来源,解析各污染源的相对贡献率,可为制定控制食品中重金属污染,保障食品安全措施提供依据.%To identify and apportion the contributions of lead pollution sources in wheat kernel,the surrounding area of a lead-zinc smelter in northwestern China was taken as the study area,local atmospheric deposits,tilled soils (0-20 cm),and the corresponding wheat samples were collected and then lead concentrations and isotope ratios was analyzed by ICP-MS . The spatial distribution of atmospheric lead settlement fluxes as well as lead concentrations in soil and wheat kernel were predicted by Ordinary Krigging methods. The contributions of lead pollution sources to wheat kernel were calculated with a linear mixing model. The results showed that lead concentrations in tilled soil ranged from 21.8 to 40.0 mg/kg,and the average level (27.1 mg/kg) was higher than background value (21.4 mg/kg) of local soil samples,which indicated that the soil in local area was polluted slightly. The lead concentrations of wheat kernel in the canyon ranged 0

  20. High-resolution quadruple sulfur isotope analyses of 3.2 Ga pyrite from the Barberton Greenstone Belt in South Africa reveal distinct environmental controls on sulfide isotopic arrays

    Science.gov (United States)

    Roerdink, Desiree L.; Mason, Paul R. D.; Whitehouse, Martin J.; Reimer, Thomas

    2013-09-01

    Multiple sulfur isotopes in Paleoarchean pyrite record valuable information on atmospheric processes and emerging microbial activity in the early sulfur cycle. Here, we report quadruple sulfur isotope data (32S, 33S, 34S, 36S) analyzed by secondary ion mass spectrometry from pyrite in a 3.26-3.23 Ga sedimentary barite deposit in the Barberton Greenstone Belt, South Africa. Our results demonstrate the presence of distinct pyrite populations and reproducible isotopic arrays in barite-free and barite-rich samples. The most 34S-depleted signatures with weakly positive Δ33S/δ34S were found in disseminated pyrite in barite, whereas positive Δ33S-values with negative Δ33S/δ34S and Δ36S/Δ33S = -0.9 ± 0.2 were exclusively observed in pyrite hosted by chert, dolomite, conglomerate and breccia. We interpret these variations to be related to local redox reactions and mixing in the sulfide phase, rather than representing primary atmospheric variability alone. The strong correlation between lithology and isotopic composition indicates distinct environments of sulfide formation linked to local sulfate concentrations and fluctuating inputs from different sulfur metabolisms. Strongly 34S-depleted sulfide was formed by microbial sulfate reduction at [SO42-] > 200 μM during deposition of barite-rich sediments, whereas isotope effects were suppressed when sulfate levels decreased during deposition of terrigeneous clastic rocks. Positive Δ33S-values indicate an increased input of sulfide derived from elemental sulfur metabolisms when sulfate concentrations fell below 200 μM. Our results support an important role for local sulfate concentrations on the expression of biogenic sulfur isotope signatures in some of the oldest rocks on Earth.

  1. Identification and Decay Studies of New, Neutron-Rich Isotopes of Bismuth, Lead and Thallium by means of a Pulsed Release Element Selective Method

    CERN Multimedia

    Mills, A; Kugler, E; Van duppen, P L E; Lettry, J

    2002-01-01

    % IS354 \\\\ \\\\ It is proposed to produce, identify and investigate at ISOLDE new, neutron-rich isotopes of bismuth, lead and thallium at the mass numbers A=215 to A=218. A recently tested operation mode of the PS Booster-ISOLDE complex, taking an advantage of the unique pulsed proton beam structure, will be used together with a ThC target in order to increase the selectivity. The decay properties of new nuclides will be studied by means of $\\beta$-, $\\gamma$- and X- ray spectroscopy methods. The expected information on the $\\beta$-half-lives and excited states will be used for testing and developing the nuclear structure models ``south-east'' of $^{208}$Pb, and will provide input data for the description of the r-process path at very heavy nuclei. The proposed study of the yields and the decay properties of those heavy nuclei produced in the spallation of $^{232}$Th by a 1~GeV proton beam contributes also the data necessary for the simulations of a hybrid accelerator-reactor system.

  2. Mesozoic vein-type Pb-Zn mineralization in the Pyrenees: Lead isotopic and fluid inclusion evidence from the Les Argentières and Lacore deposits

    Science.gov (United States)

    Munoz, Marguerite; Baron, Sandrine; Boucher, Adrien; Béziat, Didier; Salvi, Stefano

    2016-03-01

    The Axial Zone of the Pyrenees contains numerous sedimentary-exhalative Pb-Zn deposits formed during the Early Palaeozoic, which have been the subject of several studies. In addition to these, base-metal vein-type mineralizations are also exposed within the Axial Zone metasediments. These deposits, however, have not been investigated in depth and the timing and geodynamic context of their formation has not been specifically addressed. The vein-type Pb-Zn deposits of Les Argentières and Lacore are located in Devonian terranes of the eastern Pyrenees, south of the Mesozoic Aulus basin. They are interpreted as having been emplaced under an extensional setting. They are characterized by silver-rich tetrahedrite that occurs with Pb-Zn sulphides deposited by low-temperature NaCl-CaCl2 brines. Lead isotopic 208Pb/204Pb and 206Pb/204Pb ratios acquired on galena show more radiogenic values compared to those from the Palaeozoic sedimentary-exhalative mineralization, thus indicating younger ages. According to the model ages, the formation of the two deposits may be narrowed down to middle Late Triassic and Late Jurassic periods, respectively, which allows us to argue in favour of the role of pre-Alpine rifting phases in hydrothermal fluids circulation and mineralization deposition in a vein system bounding the Mesozoic Aulus basin.

  3. The chemical conditions of the late Archean Hamersley basin inferred from whole rock and pyrite geochemistry with Δ33S and δ34S isotope analyses

    Science.gov (United States)

    Gregory, Daniel D.; Large, Ross R.; Halpin, Jacqueline A.; Steadman, Jeffery A.; Hickman, Arthur H.; Ireland, Trevor R.; Holden, Peter

    2015-01-01

    The well-preserved late Archean sedimentary rocks of the Fortescue and Hamersley Basins in Western Australia offer fascinating insights into early earth ocean chemistry prior to the Great Oxidation Event (GOE). In this study, we use a combination of whole rock geochemistry, LA-ICPMS trace element analysis of sedimentary pyrite and pyrrhotite and SHRIMP-SI sulfur isotope analyses to elucidate the chemical changes in these sedimentary rocks. These proxies are used to examine chemical conditions of the ocean during the late Archean. Two to three periods of oxygen enrichment prior to the deposition of banded iron formations (BIF) can be identified. One minor stage of general increase in whole rock enrichment factors and trace element content of pyrite is observed up stratigraphy in the Jeerinah Formation, Fortescue Basin and a more substantial stage is present in the Paraburdoo and Bee Gorge Members of the Wittenoom Formation, Hamersley Basin. Some of the trace element enrichments indicate organic matter burial flux (Ni, Cr, Zn, Co and Cu) which suggests an increase in biological productivity. If the increased biological activity reflects an increase in cyanobacteria activity then an associated increase in oxygen is likely to have occurred during the deposition of the Bee Gorge Member. An increase in atmospheric oxygen would result in continental weathering of sulfide and other minerals, increasing the trace element content of the water column via erosion and avoiding excessive depletion of trace elements due to drawdown in seawater. Since some of these trace elements may also be limiting nutrients (such as Mo and Se) for the cyanobacteria, the degree of biological productivity may have further increased due to the increasing amount of trace elements introduced by oxygenation in a positive feedback loop. These periods of increased productivity and oxygen rise stopped prior to the onset of BIF deposition in the Hamersley Basin. This may be due to the ocean reaching an

  4. Application of {sup 13}C isotopic analysis to the characterization of petroleum fractions; Application de l`analyse isotopique {sup 13}C a la caracterisation de coupes petrolieres

    Energy Technology Data Exchange (ETDEWEB)

    Fixari, B.; Le Perchec, P.; Bigois, M.; Casabianca, H.; Jame, P. [CNRS, 69 - Vernaison (France)

    1994-12-31

    As a {sup 12}C-{sup 12}C bond is thermally more fragile than a {sup 12}C-{sup 13}C bond, it is observed that, after thermolysis, aromatics are enriched with {sup 13}C while light aliphatics are depleted. Using an isotopic mass spectrometry technique combined with a thermal analysis (FRACTEL analyzer) or a gas chromatography method, detailed isotopic compositions of heavy oils produced in different geological deposits and their thermal conversion products, are derived. 3 figs., 2 tabs., 5 refs.

  5. Influences upon the lead isotopic composition of organic and mineral horizons in soil profiles from the National Soil Inventory of Scotland (2007–09)

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, John G., E-mail: J.G.Farmer@ed.ac.uk [School of GeoSciences, The University of Edinburgh, Crew Building, Alexander Crum Brown Road, Edinburgh, EH9 3FF Scotland (United Kingdom); Graham, Margaret C. [School of GeoSciences, The University of Edinburgh, Crew Building, Alexander Crum Brown Road, Edinburgh, EH9 3FF Scotland (United Kingdom); Eades, Lorna J. [School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ Scotland (United Kingdom); Lilly, Allan; Bacon, Jeffrey R. [James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH Scotland (United Kingdom)

    2016-02-15

    Some 644 individual soil horizons from 169 sites in Scotland were analyzed for Pb concentration and isotopic composition. There were three scenarios: (i) 36 sites where both top and bottom (i.e. lowest sampled) soil horizons were classified as organic in nature, (ii) 67 with an organic top but mineral bottom soil horizon, and (iii) 66 where both top and bottom soil horizons were mineral. Lead concentrations were greater in the top horizon relative to the bottom horizon in all but a few cases. The top horizon {sup 206}Pb/{sup 207}Pb ratio was lesser (outside analytical error) than the corresponding bottom horizon {sup 206}Pb/{sup 207}Pb ratio at (i) 64%, (ii) 94% and (iii) 73% of sites, and greater at only (i) 8%, (ii) 3% and (iii) 8% of sites. A plot of {sup 208}Pb/{sup 207}Pb vs. {sup 208}Pb/{sup 206}Pb ratios showed that the Pb in organic top (i, ii) and bottom (i) horizons was consistent with atmospherically deposited Pb of anthropogenic origin. The {sup 206}Pb/{sup 207}Pb ratio of the organic top horizon in (ii) was unrelated to the {sup 206}Pb/{sup 207}Pb ratio of the mineral bottom horizon as demonstrated by the geographical variation in the negative shift in the ratio, a result of differences in the mineral horizon values arising from the greater influence of radiogenic Pb in the north. In (iii), the lesser values of the {sup 206}Pb/{sup 207}Pb ratio for the mineral top horizon relative to the mineral bottom horizon were consistent with the presence of anthropogenic Pb, in addition to indigenous Pb, in the former. Mean anthropogenic Pb inventories of 1.5 and 4.5 g m{sup −2} were obtained for the northern and southern halves of Scotland, respectively, consistent with long-range atmospheric transport of anthropogenic Pb (mean {sup 206}Pb/{sup 207}Pb ratio ~ 1.16). For cultivated agricultural soils (Ap), this corresponded to about half of the total Pb inventory in the top 30 cm of the soil column. - Highlights: • Pb isotope ratios were determined for 644

  6. In situ sulfur isotopes (δ{sup 34}S and δ{sup 33}S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiali [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Hu, Zhaochu, E-mail: zchu@vip.sina.com [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); The Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 102206 (China); Zhang, Wen [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Yang, Lu [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); National Research Council Canada, 1200 Montreal Rd., Ottawa, Ontario K1A 0R6 (Canada); Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China)

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N{sub 2} on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4–8 ml min{sup −1} nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N{sub 2} = 4 ml min{sup −1}). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d{sub 90} values of the particles in pressed powder pellets for accurate

  7. Application of 10(13) ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation MC-ICP-MS.

    Science.gov (United States)

    Lloyd, Nicholas S; Sadekov, Aleksey Yu; Misra, Sambuddha

    2017-10-09

    Boron isotope ratios (δ(11) B values) are used as a proxy for seawater paleo-pH, amongst several other applications. The analytical precision can be limited by the detection of low intensity ion beams from limited sample amounts. High-gain amplifiers offer improvements in signal/noise ratio and can be used to increase measurement precision and reduce sample amounts. 10(13) ohm amplifier technology has previously been applied to several radiogenic systems, but has thus far not been applied to non-traditional stable isotopes. Here we apply 10(13) ohm amplifier technology for the measurement of boron isotope ratios using solution mode MC-ICP-MS and laser ablation mode (LA-) MC-ICP-MS techniques. Precision is shown for reference materials as well as for low-volume foraminifera samples. The baseline uncertainty for a 0.1 pA (10) B ion beam is reduced to ohm amplifier technology is demonstrated to offer advantages for the determination of δ(11) B values by both MC-ICP-MS and LA-MC-ICP-MS for small samples of biogenic carbonates, such as foraminifera shells. 10(13) ohm amplifier technology will also be of benefit to other non-traditional stable isotope measurements. This article is protected by copyright. All rights reserved.

  8. The importance of mangroves, mud and sand flats, and seagrass beds as feeding areas for juvenile fishes in Chwaka Bay, Zanzibar : gut content and stable isotope analyses

    NARCIS (Netherlands)

    Lugendo, B.; Nagelkerken, I.; Velde, G. van der; Mgaya, Y.D.

    2006-01-01

    The relative importance of bay habitats, consisting of mangrove creeks and channel, seagrass beds, and mud and sand flats, as feeding grounds for a number of fish species was studied in Chwaka Bay, Zanzibar, Tanzania, using gut content analysis and stable isotope analysis of carbon and nitrogen. Gut

  9. Lead isotopic exploration intersecting mineralization zones for the depth forecast of concealed deposits——A case from Longbohe Cu deposit,Jinping, Yunnan Province,China

    Institute of Scientific and Technical Information of China (English)

    常向阳; 朱炳泉; 邹日

    2000-01-01

    Pb isotopic geochemical exploration intersecting mineralization zones have been well developed in the light of the eigenvalues V1 and V2 of three-dimensional topological projection of Pb isotopic data. The newly developed theoretical model forecasting concealed deposits has been verified in the evaluation of Longbohe copper deposit in Jinping, Yunnan Province, which is consistent with the observed law of depth variation for Pb isotopes. The forecasting results show that the depth of buried major orebody should occur at about -50 to -400 m and deeper within the eastern and western mineralization belts of Longbohe copper deposit.

  10. Surface dust wipes are the best predictors of blood leads in young children with elevated blood lead levels

    Energy Technology Data Exchange (ETDEWEB)

    Gulson, Brian, E-mail: brian.gulson@mq.edu.au [Graduate School of the Environment, Macquarie University, North Ryde NSW 2109 (Australia); CSIRO Earth Science and Resource Engineering, North Ryde NSW 2113 (Australia); Anderson, Phil [Information and Statistics Group, Australian Institute of Health and Welfare, Canberra ACT 2601 (Australia); Faculty of Health, University of Canberra, Canberra ACT 2601 (Australia); Taylor, Alan [Department of Psychology, Macquarie University, Sydney NSW 2109 (Australia)

    2013-10-15

    Background: As part of the only national survey of lead in Australian children, which was undertaken in 1996, lead isotopic and lead concentration measurements were obtained from children from 24 dwellings whose blood lead levels were ≥15 µg/dL in an attempt to determine the source(s) of their elevated blood lead. Comparisons were made with data for six children with lower blood lead levels (<10 µg/dL). Methods: Thermal ionisation and isotope dilution mass spectrometry were used to determine high precision lead isotopic ratios ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb and {sup 206}Pb/{sup 204}Pb) and lead concentrations in blood, dust from floor wipes, soil, drinking water and paint (where available). Evaluation of associations between blood and the environmental samples was based on the analysis of individual cases, and Pearson correlations and multiple regression analyses based on the whole dataset. Results and discussion: The correlations showed an association for isotopic ratios in blood and wipes (r=0.52, 95% CI 0.19–0.74), blood and soil (r=0.33, 95% CI −0.05–0.62), and blood and paint (r=0.56, 95% CI 0.09–0.83). The regression analyses indicated that the only statistically significant relationship for blood isotopic ratios was with dust wipes (B=0.65, 95% CI 0.35–0.95); there were no significant associations for lead concentrations in blood and environmental samples. There is a strong isotopic correlation of soils and house dust (r=0.53, 95% CI 0.20–0.75) indicative of a common source(s) for lead in soil and house dust. In contrast, as with the regression analyses, no such association is present for bulk lead concentrations (r=−0.003, 95% CI −0.37–0.36), the most common approach employed in source investigations. In evaluation of the isotopic results on a case by case basis, the strongest associations were for dust wipes and blood. -- Highlights: • Children with elevated blood lead ≥15 µg/dL compared with a group with <10

  11. Lead and sulfur isotopes of Guarn Halfaya and Bou Grine deposits associated to salt dome cap rocks (Diapirs zone, Northern Tunisia): sources of metals and genetic model

    Science.gov (United States)

    Jemmali, N.; Souissi, F.; Carranza, E. J. M.; Vennemann, T. W.

    2012-04-01

    The Pb-Zn ores districts at Guarn Halfaya and Bou Grine are hosted mainly by the dolostones in the contact breccias between Triassic and Upper Cretaceous and by Upper Cretaceous limestones. The mineralization occurs as lenticular, impregnations, substitutions, replacements, stratiform, vein, dissemination, and stockwork. A complex polymetallic sulfide assemblage typifies the main ore stage, dominated by sphalerite and galena, pyrite with minor chalcopyrite, arsenopyrite, and sulfosalt (grey copper). Limestone, barite and celestite dominate the gangue, with lesser calcite. Barite and celestite intergrown with main ore-stage sulfides of Oum Edeboua has δ34S values of 12.7 to 15.0 ‰, consistent with the derivation of sulfate from Triassic evaporites form the study area (12.8reduction (TSR) of Triassic sulfates at depth. However, the presence of bacterial relics suggests involvement of bacterially-mediated sulfate reduction (BSR). The lead isotope composition is homogeneous with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratio ranging between from 18.723 to 18.783, 15.667 to 15.685, and 38.806 to 38.889, respectively, and plot between the upper crust and orogene curves of Zartman and Doe (1981) which imply involvement of a well-mixed multi-source reservoir of Pb at depth. The syn-diagenetic mineralization in the Bahloul Formation and the calculate of model age suggest a Late Cretaceous age, correspond to a NE-SW to ENE-WSS regional extensional tectonic events, which likely favored migration of mineralizing fluids and eventual deposition at Guarn Halfaya and Bou Grine.

  12. Evaluating the provenance of Permian-Triassic and Palaeocene-Eocene ash beds by high precision U-Pb and Lu-Hf isotopic analyses of zircons: linking local sedimentary records to global events

    Science.gov (United States)

    Eivind Augland, Lars; Jones, Morgan; Planke, Sverre; Svensen, Henrik; Tegner, Christian

    2016-04-01

    Zircons are a powerful tool in geochronology and isotope geochemistry, as their affinity for U and Hf in the crystal structure and the low initial Pb and Lu allow for precise and accurate dating by U-Pb ID-TIMS and precise and accurate determination of initial Hf isotopic composition by solution MC-ICP-MS analysis. The U-Pb analyses provide accurate chronostratigraphic controls on the sedimentary successions and absolute age frames for the biotic evolution across geological boundaries. Moreover, the analyses of Lu-Hf by solution MC-ICP-MS after Hf-purification column chemistry provide a powerful and robust fingerprinting tool to test the provenance of individual ash beds. Here we focus on ash beds from Permian-Triassic and Palaeocene successions in Svalbard and from the Palaeocene-Eocene Thermal Maximum (PETM) in Fur, Denmark. Used in combination with whole rock geochemistry from the ash layers and the available geochemical and isotopic data from potential source volcanoes, these data are used to evaluate the provenance of the Permian-Triassic and Palaeocene ashes preserved in Svalbard and PETM ashes in Denmark. If explosive eruptions from volcanic centres such as the Siberian Traps and the North Atlantic Igneous Province (NAIP) can be traced to distal basins as ash layers, they provide robust tests of hypotheses of global synchronicity of environmental changes and biotic crises. In addition, the potential correlation of ash layers with source volcanoes will aid in constraining the extent of explosive volcanism in the respective volcanic centres. The new integrated data sets will also contribute to establish new reference sections for the study of these boundary events when combined with stable isotope data and biostratigraphy.

  13. Quantitative analysis of hydrogen and of its isotopes at the surface of the solids; Analyse quantitative de l'hydrogene et de ses isotopes a la surface des solides

    Energy Technology Data Exchange (ETDEWEB)

    Trocellier, P. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN), 91 - Gif-sur-Yvette (France)

    2007-07-01

    For analyzing the hydrogen isotopes, the nature of the probe which allows to excite the considered material and to give the hydrogen answer is multiple and is supported by various physical principles. The different available techniques are presented and several examples are given. To conclude, it is possible to determine the superficial or volume distribution of hydrogen or of one of its two heavy isotopes in choosing the most physico-chemical method. The choice of the technique to use depends of the wanted performance. In order to simplify, we can associate: 1)the sensitivity with mass spectrometry; 2)the depth resolution with the glow discharge, the SIMS and the resonant nuclear reaction; 3)the studied depth with the accelerated ions beams and the AMS; 4)the distribution image with the electrons stimulated desorption, the beta autoradiography and the ERDA; 5)the quantitative profile with the accelerated ions beams techniques; 6)the isotopic analysis with mass spectrometry and the accelerated ions beams. In order to be sure of the relevance of the measurements result, it is indicated to combine the advantages and the performances of several techniques as SIMS and NRA or FTIR and ERDA for instance. (O.M.)

  14. Evaluation of lead isotope compositions of NIST NBS 981 measured by thermal ionization mass spectrometer and multiple-collector inductively coupled plasma mass spectrometer

    Directory of Open Access Journals (Sweden)

    Honglin Yuan

    2016-09-01

    Full Text Available Because Pb isotopes can be used for tracing, they are widely used in many disciplines. The detection and analysis of Pb isotopes of bulk samples are usually conducted using thermal ionization mass spectrometer (TIMS and multiple-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, both of which need external reference materials with known isotopic compositions to correct for the mass discrimination effect produced during analysis. NIST NBS 981 is the most widely used reference material for Pb isotope analysis; however, the isotopic compositions reported by various analytical laboratories, especially those using TIMS, vary from each other. In this study, we statistically evaluated 229 reported TIMS analysis values collected by GeoReM in the last 30 years, 176 reported MC-ICP-MS analysis values, and 938 MC-ICP-MS analysis results from our laboratory in the last five years. After careful investigation, only 40 TIMS results were found to have double or triple spikes. The ratios of the overall weighted averages, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, obtained from 40 spiked TIMS reports and 1114 MC-ICP-MS results of NIST NBS 981 isotopes were 16.9406 ± 0.0003 (2s, 15.4957 ± 0.0002 (2s, and 36.7184 ± 0.0007 (2s, respectively.

  15. Archean crustal evolution in the Southern São Francisco craton, Brazil: Constraints from U-Pb, Lu-Hf and O isotope analyses

    Science.gov (United States)

    Albert, Capucine; Farina, Federico; Lana, Cristiano; Stevens, Gary; Storey, Craig; Gerdes, Axel; Dopico, Carmen Martínez

    2016-12-01

    In this study we present U-Pb and Hf isotope data combined with O isotopes in zircon from Neoarchean granitoids and gneisses of the southern São Francisco craton in Brazil. The basement rocks record three distinct magmatic events: Rio das Velhas I (2920-2850 Ma), Rio das Velhas II (2800-2760 Ma) and Mamona (2750-2680 Ma). The three sampled metamorphic complexes (Bação, Bonfim and Belo Horizonte) have distinct εHf vs. time arrays, indicating that they grew as separate terranes. Paleoarchean crust is identified as a source which has been incorporated into younger magmatic rocks via melting and mixing with younger juvenile material, assimilation and/or source contamination processes. The continental crust in the southern São Francisco craton underwent a change in magmatic composition from medium- to high-K granitoids in the latest stages, indicating a progressive HFSE enrichment of the sources that underwent anatexis in the different stages and possibly shallowing of the melting depth. Oxygen isotope data shows a secular trend towards high δ18O (up to 7.79‰) indicating the involvement of metasediments in the petrogenesis of the high potassium granitoids during the Mamona event. In addition, low δ18O values (down to 2.50‰) throughout the Meso- and Neoarchean emphasize the importance of meteoritic fluids in intra-crustal magmatism. We used hafnium isotope modelling from a compilation of detrital zircon compositions to constrain crustal growth rates and geodynamics from 3.50 to 2.65 Ga. The modelling points to a change in geodynamic process in the southern São Francisco craton at 2.9 Ga, from a regime dominated by net crustal growth in the Paleoarchean to a Neoarchean regime marked by crustal reworking. The reworking processes account for the wide variety of granitoid magmatism and are attributed to the onset of continental collision.

  16. Food web of a confined and anthropogenically affected coastal basin (the Mar Piccolo of Taranto) revealed by carbon and nitrogen stable isotopes analyses.

    Science.gov (United States)

    Bongiorni, Lucia; Fiorentino, Federica; Auriemma, Rocco; Aubry, Fabrizio Bernardi; Camatti, Elisa; Camin, Federica; Nasi, Federica; Pansera, Marco; Ziller, Luca; Grall, Jacques

    2016-07-01

    Carbon and nitrogen stable isotope analysis was used to examine the food web of the Mar Piccolo of Taranto, a coastal basin experiencing several anthropogenic impacts. Main food sources (algal detritus, seaweeds, particulate organic matter (POM) and sediment organic matter (SOM)) and benthic and pelagic consumers were collected during two contrasting seasons (June and April), at four sites distributed over two inlets, and characterized by different level of confinements, anthropogenic inputs and the presence of mussels farming. δ(13)C values of organic sources revealed an important contribution of POM to both planktonic and benthic pathways, as well as the influence of terrigenous inputs within both inlets, probably due to high seasonal land runoff. Although δ(13)C of both sources and consumers varied little between sampling sites and dates, δ(15)N spatial variability was higher and clearly reflected the organic enrichment in the second inlet as well as the uptake of anthropogenically derived material by benthic consumers. On the other hand, within the first inlet, the isotopic composition of consumers did not change in response to chemical contamination. However, the impact of polluted sediments near the Navy Arsenal in the first inlet was detectable at the level of the macrobenthic trophic structure, showing high dominance of motile, upper level consumers capable to face transient conditions and the reduction of the more resident deposit feeders. We therefore underline the great potential of matching stable isotope analysis with quantitative studies of community structure to assess the effects of multiple anthropogenic stressors.

  17. Comprehensive analytical methodology to determine hydrocarbons in marine waters using extraction disks coupled to glass fiber filters and compound-specific isotope analyses.

    Science.gov (United States)

    Ternon, Eva; Tolosa, Imma

    2015-07-24

    Solid-phase extraction of both aliphatic (AHs) and aromatic polycyclic hydrocarbons (PAHs) from seawater samples was evaluated using a GFF filter stacked upon an octadecyl bonded silica (C18) disk. Stable-isotope measurements were developed on hydrocarbons extracted from both GFF and C18-disks in order to characterize the source of hydrocarbons. A clear partition of hydrocarbon compounds between the dissolved and the particulate phase was highlighted. PAHs showed a higher affinity with the dissolved phase (recoveries efficiency of 48-71%) whereas AHs presented strong affinity with the particulate phase (up to 76% of extraction efficiency). Medium volumes of seawater samples were tested and no breakthrough was observed for a 5L sample. Isotopic fractionation was investigated within all analytical steps but none was evidenced. This method has been applied to harbor seawater samples and very low AH and PAH concentrations were achieved. Due to the low concentration levels of hydrocarbons in the samples, the source of hydrocarbons was determined by molecular indices rather than isotopic measurements and a pyrolytic origin was evidenced. The aliphatic profile also revealed the presence of long-chain linear alkylbenzenes (LABs). The methodology presented here would better fit to polluted coastal environments affected by recent oil spills.

  18. Calibration and correction of LA-ICP-MS and LA-MC-ICP-MS analyses for element contents and isotopic ratios

    Directory of Open Access Journals (Sweden)

    Jie Lin

    2016-06-01

    Full Text Available LA-ICP-MS and LA-MC-ICP-MS have been the techniques of choice for achieving accurate and precise element content and isotopic ratio, the state-of-the-art technique combines the advantages of low detection limits with high spatial resolution, however, the analysis accuracy and precision are restricted by many factors, such as sensitivity drift, elemental/isotopic fractionation, matrix effects, interferences and the lack of sufficiently matrix-matched reference materials. Thus, rigorous and suitable calibration and correction methods are needed to obtain quantitative data. This review systematically summarized and evaluated the interference correction, quantitative calculation and sensitivity correction strategies in order to provide the analysts with suitable calibration and correction strategies according to the sample types and the analyzed elements. The functions and features of data reduction software ICPMSDataCal were also outlined, which can provide real-time and on-line data reduction of element content and isotopic ratios analyzed by LA-ICP-MS and LA-MC-ICP-MS.

  19. delta 13C analyses of vegetable oil fatty acid components, determined by gas chromatography--combustion--isotope ratio mass spectrometry, after saponification or regiospecific hydrolysis.

    Science.gov (United States)

    Woodbury, S E; Evershed, R P; Rossell, J B

    1998-05-01

    The delta 13C values of the major fatty acids of several different commercially important vegetable oils were measured by gas chromatography--combustion--isotope ratio mass spectrometry. The delta 13C values obtained were found to fall into two distinct groups, representing the C3 and C4 plants classes from which the oils were derived. The delta 13C values of the oils were measured by continuous flow elemental isotope ratio mass spectrometry and were found to be similar to their fatty acids, with slight differences between individual fatty acids. Investigations were then made into the influence on the delta 13C values of fatty acids of the position occupied on the glycerol backbone. Pancreatic lipase was employed to selectively hydrolyse fatty acids from the 1- and 3-positions with the progress of the reaction being followed by high-temperature gas chromatography in order to determine the optimum incubation time. The 2-monoacylglycerols were then isolated by thin-layer chromatography and fatty acid methyl esters prepared. The delta 13C values obtained indicate that fatty acids from any position on the glycerol backbone are isotopically identical. Thus, whilst quantification of fatty acid composition at the 2-position and measurement of delta 13C values of oils and their major fatty acids are useful criteria in edible oil purity assessment, measurement of delta 13C values of fatty acids from the 2-position does not assist with oil purity assignments.

  20. Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California

    Science.gov (United States)

    Bacon, C.R.; Kurasawa, H.; Delevaux, M.H.; Kistler, R.W.; Doe, B.R.

    1984-01-01

    The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs. ?? 1984 Springer-Verlag.

  1. Strong linkage of polar cod (Boreogadus saida) to sea ice algae-produced carbon: Evidence from stomach content, fatty acid and stable isotope analyses

    Science.gov (United States)

    Kohlbach, Doreen; Schaafsma, Fokje L.; Graeve, Martin; Lebreton, Benoit; Lange, Benjamin Allen; David, Carmen; Vortkamp, Martina; Flores, Hauke

    2017-03-01

    The polar cod (Boreogadus saida) is considered an ecological key species, because it reaches high stock biomasses and constitutes an important carbon source for seabirds and marine mammals in high-Arctic ecosystems. Young polar cod (1-2 years) are often associated with the underside of sea ice. To evaluate the impact of changing Arctic sea ice habitats on polar cod, we examined the diet composition and quantified the contribution of ice algae-produced carbon (αIce) to the carbon budget of polar cod. Young polar cod were sampled in the ice-water interface layer in the central Arctic Ocean during late summer 2012. Diets and carbon sources of these fish were examined using 4 approaches: (1) stomach content analysis, (2) fatty acid (FA) analysis, (3) bulk nitrogen and carbon stable isotope analysis (BSIA) and (4) compound-specific stable isotope analysis (CSIA) of FAs. The ice-associated (sympagic) amphipod Apherusa glacialis dominated the stomach contents by mass, indicating a high importance of sympagic fauna in young polar cod diets. The biomass of food measured in stomachs implied constant feeding at daily rates of ∼1.2% body mass per fish, indicating the potential for positive growth. FA profiles of polar cod indicated that diatoms were the primary carbon source, indirectly obtained via amphipods and copepods. The αIce using bulk isotope data from muscle was estimated to be >90%. In comparison, αIce based on CSIA ranged from 34 to 65%, with the highest estimates from muscle and the lowest from liver tissue. Overall, our results indicate a strong dependency of polar cod on ice-algae produced carbon. This suggests that young polar cod may be particularly vulnerable to changes in the distribution and structure of sea ice habitats. Due to the ecological key role of polar cod, changes at the base of the sea ice-associated food web are likely to affect the higher trophic levels of high-Arctic ecosystems.

  2. Stable isotope analyses of NO2-, NO3-, and N2O in the hypersaline ponds and soils of the McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Peters, Brian; Casciotti, Karen L.; Samarkin, Vladimir A.; Madigan, Michael T.; Schutte, Charles A.; Joye, Samantha B.

    2014-06-01

    Nitrous oxide (N2O) is produced in significant quantities in the soils and lakes of the McMurdo Dry Valleys, Antarctica. Unraveling the mechanisms of N2O production in these soils and ponds is of great interest due to the extreme arid and cold conditions, which are hostile to life. Recent studies have shown production of N2O having unique stable isotopic signatures in certain Dry Valley soils through abiotic reduction of nitrate (NO3-) and nitrite (NO2-) on active surfaces of Fe(II)-containing minerals, a process known as ‘chemodenitrification’. In this study, δ15N and δ18O of N2O, NO2-, and NO3-, as well as the N2O site preference (SP), were measured at three sites to evaluate the role of chemodenitrification in N2O production. The δ15N and δ18O values in NO3- indicated an atmospheric source, while δ15N values in NO2- (-150‰) were indicative of abiotic reactions. Instead of finding unique SP values for N2O at Dry Valley sites, SP values mostly fell within the range associated with microbial N2O production mechansims. The δ15N and δ18O of N2O were also within a range of values expected for various biological N2O production mechanisms. However, efforts to detect biological activity in Don Juan Pond (DJP), a hypersaline pond in the Wright Valley, have been largely unsuccessful. We consider two possible scenarios for N2O production at DJP: (1) abiotic production in the pond, or (2) biological production in nearby freshwater and transport to the pond. Although little is known about the isotopic systematics of abiotic N2O production, these results indicate that if the observed N2O was produced by an abiotic mechanism, its isotopic signature is indistinguishable from that expected from a mixture of several microbial processes and thus, the formation pathway cannot be determined from isotopic composition alone.

  3. Elevated CO₂ increases tree-level intrinsic water use efficiency: insights from carbon and oxygen isotope analyses in tree rings across three forest FACE sites.

    Science.gov (United States)

    Battipaglia, Giovanna; Saurer, Matthias; Cherubini, Paolo; Calfapietra, Carlo; McCarthy, Heather R; Norby, Richard J; Francesca Cotrufo, M

    2013-01-01

    Elevated CO₂ increases intrinsic water use efficiency (WUE(i) ) of forests, but the magnitude of this effect and its interaction with climate is still poorly understood. We combined tree ring analysis with isotope measurements at three Free Air CO₂ Enrichment (FACE, POP-EUROFACE, in Italy; Duke FACE in North Carolina and ORNL in Tennessee, USA) sites, to cover the entire life of the trees. We used δ¹³C to assess carbon isotope discrimination and changes in water-use efficiency, while direct CO₂ effects on stomatal conductance were explored using δ¹⁸O as a proxy. Across all the sites, elevated CO₂ increased ¹³C-derived water-use efficiency on average by 73% for Liquidambar styraciflua, 77% for Pinus taeda and 75% for Populus sp., but through different ecophysiological mechanisms. Our findings provide a robust means of predicting water-use efficiency responses from a variety of tree species exposed to variable environmental conditions over time, and species-specific relationships that can help modelling elevated CO₂ and climate impacts on forest productivity, carbon and water balances.

  4. Discoveries of isotopes by fission

    Indian Academy of Sciences (India)

    M Thoennessen

    2015-09-01

    Of the about 3000 isotopes presently known, about 20% have been discovered in fission. The history of fission as it relates to the discovery of isotopes as well as the various reaction mechanisms leading to isotope discoveries involving fission are presented.

  5. Sources of organic matter (PAHs and n-alkanes) in PM2.5 of Beijing in haze weather analyzed by combining the C-N isotopic and PCA-MLR analyses.

    Science.gov (United States)

    Guo, Xinyue; Li, Cai; Gao, Yang; Tang, Lei; Briki, Meryem; Ding, Huaijian; Ji, Hongbing

    2016-03-01

    Organic molecular composition and carbon and nitrogen isotope ratios of PM2.5 samples collected in November 2013 were analyzed using gas chromatography/mass spectrometry and isotope ratio mass spectrometry. The samples represented six potential sources and seven sampling sites situated in concentric zones around Beijing under both haze and non-haze conditions. Our results showed that the average concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes were 258.2 ± 208.8 ng m(-3) and 499.5 ± 347.8 ng m(-3), while the δ(13)C and δ(15)N values for PM2.5 varied from -26.29 to -25.26‰ and from 8.68 to 14.50‰ with an average of -25.70 ± 0.3‰ and 11.97 ± 1.79‰, respectively. The highest concentrations of PAHs and n-alkanes were recorded in the sixth ring road, with the lowest ones in the third ring road. Concentrations of PAHs during haze were higher than during non-haze conditions, while concentrations of n-alkanes were not markedly different. Principal component analysis/multiple linear regression analyses indicated that the main sources of PAHs were vehicle and coal combustion emissions, while n-alkanes had high contributions from petroleum emissions. These sources were supported by isotopic analyses. Thus, the main sources of organic matter contributing to haze in Beijing were coal combustion and vehicle emissions. Such results provide guidance towards managing haze in Beijing.

  6. Plasticity of trophic interactions among sharks from the oceanic south-western Indian Ocean revealed by stable isotope and mercury analyses

    Science.gov (United States)

    Kiszka, Jeremy J.; Aubail, Aurore; Hussey, Nigel E.; Heithaus, Michael R.; Caurant, Florence; Bustamante, Paco

    2015-02-01

    Sharks are a major component of the top predator guild in oceanic ecosystems, but the trophic relationships of many populations remain poorly understood. We examined chemical tracers of diet and habitat (δ15N and δ13C, respectively) and total mercury (Hg) concentrations in muscle tissue of seven pelagic sharks: blue shark (Prionace glauca), short-fin mako shark (Isurus oxyrinchus), oceanic whitetip shark (Carcharhinus longimanus), scalloped hammerhead shark (Sphyrna lewini), pelagic thresher shark (Alopias pelagicus), crocodile shark (Pseudocarcharias kamoharai) and silky shark (Carcharhinus falciformis), from the data poor south-western tropical Indian Ocean. Minimal interspecific variation in mean δ15N values and a large degree of isotopic niche overlap - driven by high intraspecific variation in δ15N values - was observed among pelagic sharks. Similarly, δ13C values of sharks overlapped considerably for all species with the exception of P. glauca, which had more 13C-depleted values indicating possibly longer residence times in purely pelagic waters. Geographic variation in δ13C, δ15N and Hg were observed for P. glauca and I. oxyrinchus. Mean Hg levels were similar among species with the exception of P. kamoharai which had significantly higher Hg concentrations likely related to mesopelagic feeding. Hg concentrations increased with body size in I. oxyrinchus, P. glauca and C. longimanus. Values of δ15N and δ13C varied with size only in P. glauca, suggesting ontogenetic shifts in diets or habitats. Together, isotopic data indicate that - with few exceptions - variance within species in trophic interactions or foraging habitats is greater than differentiation among pelagic sharks in the south-western Indian Ocean. Therefore, it is possible that this group exhibits some level of trophic redundancy, but further studies of diets and fine-scale habitat use are needed to fully test this hypothesis.

  7. Feeding habitats of the Gulf sturgeon, Acipenser oxyrinchus desotoi, in the Suwannee and Yellow rivers, Florida, as identified by multiple stable isotope analyses

    Science.gov (United States)

    Sulak, Kenneth J.; Berg, James J.; Randall, Michael

    2012-01-01

    Stable 13C, 15N, and 34S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee subadults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than emigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of samples), comprised of juveniles and subadults, displayed 13C signatures indicating continued feeding in freshwater during the spring immigration and fall emigration periods. This cannot be interpreted as incidental feeding since it resulted in a 20.5% turnover in tissue δ13C signatures over a 1–3 month period. Cessation of feeding in the general population does not coincide with high river water temperatures. The hypothesis of reduced feeding in freshwater due to localized prey depletion as a result of spatial activity restriction is not supported by the present study. Instead, Suwannee River A. o. desotoi appear to follow two trophic alternatives; 1) complete cessation of feeding immediately upon immigration in spring, continuing through emigration 8–9 months later (the predominant alternative); 2) continued intensive feeding for 1–3 months following immigration, switching to freshwater prey, selected primarily from high trophic levels (i.e., large prey). Stable –34S data verifies that recently immigrated, fully-anadromous A. o. desotoi adults had fed in nearshore marine waters, not offshore waters.

  8. Determining lead sources in Mexico using the lead isotope ratio La identificación de fuentes de exposición a plomo en México a través de la determinación de la razón de isótopos de plomo

    Directory of Open Access Journals (Sweden)

    Madhu Chaudhary-Webb

    2003-01-01

    Full Text Available OBJECTIVE: Lead poisoning can, in some cases, be traced to a specific route or source of exposure on the basis of the individual's blood lead isotope ratio. To assess the major source of lead exposure among women residing in Mexico City, we compared blood, ceramic, and gasoline lead isotope ratios. MATERIAL AND METHODS: The study population, randomly selected from participants of a large trial, (1/1996-12/1996 comprised of 16 women whose lead levels exceeded 10 µg/dl and who reported using lead-glazed ceramics. Lead isotope ratios were performed on a Perkin Elmer 5000 Inductively Coupled Plasma Mass Spectrometer (ICP-MS interfaced with a Perkin Elmer HGA-600MS Electrothermal Vaporization System (ETV. RESULTS: The isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb of both the blood specimens and their corresponding ceramic specimens were highly correlated, with r=0.9979, r²=0.9958, r=0.9957, r²=0.9915 and r=0.9945, r²=0.9890 values for the three isotope ratios, respectively, suggesting that the lead exposure most likely resulted from the use of these ceramic. Measurements of lead isotope ratios from leaded gasoline in use at the time of blood sampling, differed from those in blood and ceramics. CONCLUSIONS: Determining lead isotope ratios can be an efficient tool to identify a major source of lead exposure and to support the implementation of public health prevention and control measures.OBJETIVO: Identificar la fuente principal de exposición a plomo entre mujeres residentes en la Ciudad de México, por medio de la comparación de las razones de isótopos de plomo en sangre, cerámica y gasolina. MATERIAL Y MÉTODOS: La población de estudio fue seleccionada aleatoriamente de participantes de una muestra obtenida de enero a diciembre de 1996 y consistió en 16 mujeres con niveles de plomo mayores a 10 µg/dl, que usaban cerámica vidriada con plomo. Las razones de isótopos de plomo se obtuvieron con un espectrómetro de masa de

  9. Evaluation of laser ablation double-focusing SC-ICPMS for “common” lead isotopic measurements in silicate glasses and mineral

    Science.gov (United States)

    Pietruszka, Aaron J.; Neymark, Leonid

    2017-01-01

    An analytical method for the in situ measurement of “common” Pb isotope ratios in silicate glasses and minerals using a 193-nm excimer laser ablation (LA) system with a double-focusing single-collector (SC)-ICPMS is presented and evaluated as a possible alternative to multiple-collector (MC)-ICPMS. This LA-SC-ICPMS technique employs fast-scanning ion deflectors to sequentially place a series of flat-topped isotope peaks into a single ion-counting detector at a fixed accelerating voltage and magnetic field strength. Reference materials (including NIST, MPI-DING, and USGS glasses) are used to identify two analytical artifacts on the Pb isotope ratios (expressed here as heavier/lighter isotopes) when corrected for mass bias relative to NIST SRM610. The first artifact is characterized by anomalously low Pb isotope ratios (~0.1%/AMU) when SRM610 is analyzed in raster mode as an unknown at small spot sizes (materials (BCR-2G, GOR132-G, and T1-G). These offsets are thought to be caused by one or more non-spectral matrix effects related to differences in the ablation behavior, composition, or physical properties of these reference materials compared to the bracketing SRM610 standard. The precision (±2SD) of our LA-SC-ICPMS Pb isotopic measurements is similar to (207Pb/206Pb and 208Pb/206Pb, or 20XPb/206Pb) or better than (206Pb/204Pb,207Pb/204Pb, and 208Pb/204Pb, or 20XPb/204Pb) a series of published studies that used a different type of SC-ICPMS and obtained a factor of ~3-4 higher sensitivity for Pb. An increase in the sensitivity of our LA-SC-ICPMS would likely improve the precision of the 20XPb/206Pb and 20XPb/204Pb ratios for low-Pb materials (making the technique broadly similar to LA-MC-ICPMS (particularly compared to methods that rely upon at least one ion-counting detector). Further improvement in the precision of the 20XPb/206Pb and 20XPb/204Pb ratios for high-Pb materials (>5 ppm) by LA-SC-ICPMS is unlikely, and in this case, LA-MC-ICPMS remains the

  10. High-precision analysis on annual variations of heavy metals, lead isotopes and rare earth elements in mangrove tree rings by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yu Kefu [South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xin-Gang Road, Guangzhou 510301 (China) and Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis (CMM), University of Queensland, Qld 4072 (Australia)]. E-mail: kefuyu@scsio.ac.cn; Kamber, Balz S. [Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis (CMM), University of Queensland, Qld 4072 (Australia); Department of Earth Sciences, Laurentian University, Sudbury, ONP3E2C6 (Canada); Lawrence, Michael G. [Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis (CMM), University of Queensland, Qld 4072 (Australia); Greig, Alan [Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis (CMM), University of Queensland, Qld 4072 (Australia); School of Earth Sciences, University of Melbourne, Vic. 3010 (Australia); Zhao Jianxin [Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis (CMM), University of Queensland, Qld 4072 (Australia)

    2007-02-15

    Annual variations from 1982 to 1999 of a wide range of trace elements and reconnaissance Pb isotopes ({sup 207}Pb/{sup 206}Pb and {sup 208}Pb/{sup 206}Pb) were analyzed by solution ICP-MS on digested ash from mangrove Rhizophora apiculata, obtained from Leizhou Peninsula, along northern coast of South China Sea. The concentrations of the majority of elements show a weak declining trend with growth from 1982 to 1999, punctuated by several high concentration spikes. The declining trends are positively correlated with ring width and negatively correlated with inferred water-use efficiency, suggesting a physiological control over metal-uptake in this species. The episodic metal concentration-peaks cannot be interpreted with lateral movement or growth activities and appear to be related to environmental pollution events. Pb isotope ratios for most samples plot along the 'Chinese Pb line' and clearly document the importance of gasoline Pb as a source of contaminant. Shale-normalised REE + Y patterns are relatively flat and consistent across the growth period, with all patterns showing a positive Ce anomaly and elevated Y/Ho ratio. The positive Ce anomaly is observed regardless of the choice of normaliser, in contrast to previously reported REE patterns for terrestrial and marine plants. This pilot study of trace element, REE + Y and Pb isotope distribution in mangrove tree rings indicates the potential use of mangroves as monitors of historical environmental change.

  11. High-precision analysis on annual variations of heavy metals, lead isotopes and rare earth elements in mangrove tree rings by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Yu, Ke-Fu; Kamber, Balz S.; Lawrence, Michael G.; Greig, Alan; Zhao, Jian-Xin

    2007-02-01

    Annual variations from 1982 to 1999 of a wide range of trace elements and reconnaissance Pb isotopes ( 207Pb/ 206Pb and 208Pb/ 206Pb) were analyzed by solution ICP-MS on digested ash from mangrove Rhizophora apiculata, obtained from Leizhou Peninsula, along northern coast of South China Sea. The concentrations of the majority of elements show a weak declining trend with growth from 1982 to 1999, punctuated by several high concentration spikes. The declining trends are positively correlated with ring width and negatively correlated with inferred water-use efficiency, suggesting a physiological control over metal-uptake in this species. The episodic metal concentration-peaks cannot be interpreted with lateral movement or growth activities and appear to be related to environmental pollution events. Pb isotope ratios for most samples plot along the 'Chinese Pb line' and clearly document the importance of gasoline Pb as a source of contaminant. Shale-normalised REE + Y patterns are relatively flat and consistent across the growth period, with all patterns showing a positive Ce anomaly and elevated Y/Ho ratio. The positive Ce anomaly is observed regardless of the choice of normaliser, in contrast to previously reported REE patterns for terrestrial and marine plants. This pilot study of trace element, REE + Y and Pb isotope distribution in mangrove tree rings indicates the potential use of mangroves as monitors of historical environmental change.

  12. Reproductive and feeding spatial dynamics of the black scabbardfish, Aphanopus carbo Lowe, 1839, in NE Atlantic inferred from fatty acid and stable isotope analyses

    Science.gov (United States)

    Farias, Inês; Figueiredo, Ivone; Janeiro, Ana Isabel; Bandarra, Narcisa Maria; Batista, Irineu; Morales-Nin, Beatriz

    2014-07-01

    The black scabbardfish (Aphanopus carbo) is a benthopelagic species widely distributed across the NE Atlantic, where it is admitted to perform a clockwise migration throughout its life cycle stimulated by feeding and reproduction. To overcome the limitations of direct observation of this species, fatty acids profile (FA) and δ15N and δ13C stable isotopes (SI) were analyzed in the muscle tissue of the black scabbardfish and related with diet and maturity. Specimens were collected in four geographic areas in the NE Atlantic: Iceland, the west of the British Isles, mainland Portugal, and Madeira. For all areas, the FA profile was related with the different phases of the reproductive cycle and with diet, whereas the SI were related with diet, environmental characteristics, such as latitude and depth, and particulate organic matter (POM). Stomach content of black scabbardfish caught off mainland Portugal was analyzed and the most frequent prey item identified was the lophogastrid crustacean Gnathophausia zoea, followed by the cephalopod Mastigotheutis spp. and the teleost Rouleina maderensis. For specimens from Iceland and the west of the British Isles, monounsaturated fatty acids (MUFA) were the most important FA, followed by polyunsaturated (PUFA) and saturated FA (SFA), whereas for specimens from mainland Portugal and from Madeira the sequences were PUFA>MUFA>SFA and PUFA>SFA>MUFA, respectively. Immature specimens from the first three areas were found to be accumulating oleic acid which is an intermediate product of the metabolic pathway that transforms SFA to MUFA and these into PUFA. Specimens caught off Madeira were mature and showed a significant prevalence of ARA and DHA which are PUFA with an important role in reproduction. δ15N was significantly higher in the muscle of black scabbardfish from Madeira, whereas δ13C was significantly lower in specimens from Iceland. The low isotopic ratios as well as the prevalence of certain fatty acid trophic markers (FATM

  13. Carbonate concretions as a significant component of ancient marine carbon cycles: Insights from paired organic and inorganic carbon isotope analyses of a Cretaceous shale

    Science.gov (United States)

    Loyd, S. J.

    2014-12-01

    Carbonate concretions often occur within fine-grained, organic-rich sedimentary rocks. This association reflects the common production of diagenetic minerals through biologic cycling of organic matter. Chemical analysis of carbonate concretions provides the rare opportunity to explore ancient shallow diagenetic environments, which are inherently transient due to progressive burial but are an integral component of the marine carbon cycle. The late Cretaceous Holz Shale (~80 Ma) contains abundant calcite concretions that exhibit textural and geochemical characteristics indicative of relatively shallow formation (i.e., near the sediment-water interface). Sampled concretions contain between 5.4 and 9.8 wt.% total inorganic carbon (TIC), or ~45 and 82 wt.% CaCO3, compared to host shale values which average ~1.5 wt.% TIC. Organic carbon isotope compositions (δ13Corg) are relatively constant in host and concretion samples ranging from ­-26.3 to -24.0‰ (VPDB). Carbonate carbon isotope compositions (δ13Ccarb) range from -22.5 to -3.4‰, indicating a significant but not entirely organic source of carbon. Concretions of the lower Holz Shale exhibit considerably elevated δ13Ccarb values averaging -4.8‰, whereas upper Holz Shale concretions express an average δ13Ccarb value of -17.0‰. If the remaining carbonate for lower Holz Shale concretions is sourced from marine fluids and/or dissolved marine carbonate minerals (e.g., shells), a simple mass balance indicates that ~28% of concretion carbon was sourced from organic matter and ~72% from late Cretaceous marine inorganic carbon (with δ13C ~ +2.5‰). Upper Holz Shale calculations indicate a ~73% contribution from organic matter and a ~27% contribution from inorganic carbon. When normalized for carbonate, organic contents within the concretions are ~2-13 wt.% enriched compared to host contents. This potentially reflects the protective nature of cementation that acts to limit permeability and chemical destruction of

  14. Evaluation of the effect of the 2011 Tsunami on coastal forests by means of multiple isotopic analyses on tree-rings

    Science.gov (United States)

    Lopez Caceres, Maximo Larry; Nakano, Sayako; Ferrio Diaz, Juan Pedro; Hayashi, Mika; Nakatsuka, Takeshi; Sano, Masaki; Yamanaka, Toshiro; Nobori, Yoshihiro

    2017-04-01

    The 2011 Mega-Tsunami destroyed at different degrees the coastal forests in eastern Japan, which for decades have protected inland agriculture and livelihood of the inhabitants in this region. This study investigates the effect of the tsunami on coastal forests and the physiological processes involved by means of stable isotope (13C, 15N and 18O) analysis for the period 2002-2014. Based on the results, annual tree-ring width from 2011 to 2014 decreased approximately 80% compared to the period previous to the Tsunami (2002-2010). Considering that soil salt concentration drastically decreased in September 2011 after a typhoon that dumped 350 mm of rain, the impact appeared to be limited in time. Nevertheless soil electric conductivity showed that spatial variability was strongly correlated with tree mortality in the study plot. The multiple isotope analysis showed that the reduction in growth was associated with a reduction in 13C discrimination following stomatal closure caused by soil salinity in 2011. Two years after the tsunami photosynthetic recovery, implied from decreasing values of 13C in tree-rings, did not translate in tree-growth, indicating a shift in carbon allocation strategy as trees recovered from the strong disturbance caused by the Tsunami. Tree-ring 18O did not show the abrupt increase observed for 13C and could not be used as an indicator of soil salinity. No changes in tree-ring 18O compared to 13C should indicate an increase in assimilation rates but that was not supported by the limited tree-ring growth or by the subsequent recovery of 13C. Nitrogen availability did not change before and after the Tsunami as suggested by values of tree-ring 15N which agree with values found in previous studies. The lack of the effect of salinity on tree-ring 15N could be related to the lack of changes in soil layers where inorganic nitrogen is found and/or because of the salt resistant mycorrhizal fungi typical of Japanese forests.

  15. Pb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities

    Science.gov (United States)

    Ayuso, Robert A.; Foley, Nora K.

    2016-01-01

    Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, PA, were evaluated to discern anthropogenic from geogenic sources. Pb (n = 144) and Sr (n = 40) isotopic data and REE (n = 29) data were determined for waters from residential wells, test wells (drilled for this study), and surface waters from pond and creeks. Local soils, sediments, bedrock, Zn-Pb mineralization and coal were also analyzed (n = 94), together with locally used Pb-As pesticide (n = 5). Waters from residential and test wells show overlapping values of 206Pb/207Pb, 208Pb/207Pb and 87Sr/86Sr. Larger negative Ce anomalies (Ce/Ce*) distinguish residential wells from test wells. Results show that residential and test well waters, sediments from residential water filters in water tanks, and surface waters display broad linear trends in Pb isotope plots. Pb isotope data for soils, bedrock, and pesticides have contrasting ranges and overlapping trends. Contributions of Pb from soils to residential well waters are limited and implicated primarily in wells having shallow water-bearing zones and carrying high sediment contents. Pb isotope data for residential wells, test wells, and surface waters show substantial overlap with Pb data reflecting anthropogenic actions (e.g., burning fossil fuels, industrial and urban processing activities). Limited contributions of Pb from bedrock, soils, and pesticides are evident. High Pb concentrations in the residential waters are likely related to sediment build up in residential water tanks. Redox reactions, triggered by influx of groundwater via wells into the residential water systems and leading to subtle changes in pH, are implicated in precipitation of Fe oxyhydroxides

  16. 夏商周青铜器铅同位素示踪研究数据库的构建%A Lead Isotope Ratio Data Base of Ancient Chinese Bronzes

    Institute of Scientific and Technical Information of China (English)

    金正耀

    2005-01-01

    A data base of lead isotope ratio of ancient Chinese bronzes is set up. There are 2 888 members, including bronze objects, casting remains, and related ores, etc. in the file. The file contents of data base are made from analysis work on Chinese bronze previously carried out in several laboratories in China, Japan and USA. The main body of the file contents is formed from records, analysis data, reference documents, and images. The data base is designed for sharing information in provenance study on raw metal material for bronze production in China Bronze Age.

  17. 40Ar/39Ar dating, geochemistry, and isotopic analyses of the quaternary Chichinautzin volcanic field, south of Mexico City: implications for timing, eruption rate, and distribution of volcanism

    Science.gov (United States)

    Arce, J. L.; Layer, P. W.; Lassiter, J. C.; Benowitz, J. A.; Macías, J. L.; Ramírez-Espinosa, J.

    2013-12-01

    Monogenetic structures located at the southern and western ends of the Chichinautzin volcanic field (Trans-Mexican Volcanic Belt, Central Mexico) yield 40Ar/39Ar ages ranging from 1.2 Ma in the western portion of the field to 1.0-0.09 Ma in the southern portion, all of which are older than the volcanic field. These new ages indicate: (1) an eruption rate of 0.47 km3/kyr, which is much lower than the 11.7 km3/kyr previously estimated; (2) that the Chichinautzin magmatism coexisted with the Zempoala (0.7 Ma) and La Corona (1.0 Ma) polygenetic volcanoes on the southern edge of Las Cruces Volcanic Range (Trans-Mexican Volcanic Belt); and confirm (3) that the drainage system between the Mexico and Cuernavaca basins was closed during early Pleistocene forming the Texcoco Lake. Whole-rock chemistry and Sr, Nd, and Pb isotopic data indicate heterogeneous magmatism throughout the history of Chichinautzin activity that likely reflects variable degrees of slab and sediment contributions to the mantle wedge, fractional crystallization, and crustal assimilation. Even with the revised duration of volcanism within the Chichinautzin Volcanic Field, its eruption rate is higher than most other volcanic fields of the Trans-Mexican Volcanic Belt and is comparable only to the Tacámbaro-Puruaran area in the Michoacán-Guanajuato Volcanic Field to the west. These variations in eruption rates among different volcanic fields may reflect a combination of variable subduction rates of the Rivera and Cocos plates along the Middle America Trench, as well as different distances from the trench, variations in the depth with respect to the subducted slab, or the upper plate characteristics.

  18. Speciation and reactivity of lead and zinc in heavily and poorly contaminated soils: Stable isotope dilution, chemical extraction and model views.

    Science.gov (United States)

    Ren, Zong-Ling; Sivry, Yann; Tharaud, Mickaël; Cordier, Laure; Li, Yongtao; Dai, Jun; Benedetti, Marc F

    2017-06-01

    Correct characterization of metal speciation and reactivity is a prerequisite for the risk assessment and remedial activity management of contaminated soil. To better understand the intrinsic reactivity of Pb and Zn, nine heavily and poorly contaminated soils were investigated using the combined approaches of chemical extractions, multi-element stable isotopic dilution (ID) method, and multi-surface modelling. The ID results show that 0.1-38% of total Pb and 3-45% of total Zn in the studied soils are isotopically exchangeable after a 3-day equilibration. The intercomparison between experimental and modelling results evidences that single extraction with 0.43 M HNO3 solubilizes part of non-isotopically exchangeable fraction of Pb and Zn in the studied soils, and cannot be used as a surrogate for ID to assess labile Pb and Zn pools in soil. Both selective sequential extraction (SSE) and modelling reveal that Mn oxides are the predominant sorption surface for Pb in the studied soils; while Zn is predicted to be mainly associated with soil organic matter in the soil with low pH and Fe/Mn oxides in the soils with high pH. Multi-surface modelling can provide a reasonable prediction of Pb and Zn adsorption onto different soil constituents for the most of the studied soils. The modelling could be a promising tool to decipher the underlying mechanism that controls metal reactivity in soil, but the submodel for Mn oxides should be incorporated and the model parameters, especially for the 2-pK diffuse layer model for Mn oxides, should be updated in the further studies. Copyright © 2017. Published by Elsevier Ltd.

  19. Lunar Science Conference, 4th, Houston, Tex., March 5-8, 1973, Proceedings. Volume 1 - Mineralogy and petrology. Volume 2 - Chemical and isotope analyses. Organic chemistry. Volume 3 - Physical properties

    Science.gov (United States)

    Gose, W. A.

    1973-01-01

    The mineralogy, petrology, chemistry, isotopic composition, and physical properties of lunar materials are described in papers detailing methods, results, and implications of research on samples returned from eight lunar landing sites: Apollo 11, 12, 14, 15, 16, 17, and Luna 16 and 20. The results of experiments conducted or set up on the lunar surface by the astronauts are also described along with observations taken from Command Modules and subsatellites. Major topics include general geology, soil and breccia studies, petrologic studies, mineralogic analyses, elemental compositions, radiometric age determinations, rare gas chemistry, radionuclides, organogenic compounds, particle track records, thermal properties, seismic studies, resonance studies, orbital mapping, lunar atmosphere, magnetic studies, electrical studies, optical properties, and microcratering. Individual items are announced in this issue.

  20. Lunar Science Conference, 4th, Houston, Tex., March 5-8, 1973, Proceedings. Volume 1 - Mineralogy and petrology. Volume 2 - Chemical and isotope analyses. Organic chemistry. Volume 3 - Physical properties

    Science.gov (United States)

    Gose, W. A.

    1973-01-01

    The mineralogy, petrology, chemistry, isotopic composition, and physical properties of lunar materials are described in papers detailing methods, results, and implications of research on samples returned from eight lunar landing sites: Apollo 11, 12, 14, 15, 16, 17, and Luna 16 and 20. The results of experiments conducted or set up on the lunar surface by the astronauts are also described along with observations taken