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Sample records for natural geochemical tracer

  1. Using Natural Geochemical Tracers to Discern the Dominant Sources of Freshwater into Biscayne Bay, Southeast Florida

    Science.gov (United States)

    Stalker, J. C.; Price, R. M.; Swart, P. K.

    2005-05-01

    Biscayne Bay is a sub-tropical estuary located on the carbonate platform of south Florida. The water occupying Biscayne Bay is a balance of saltwater influx from the open ocean and freshwater inputs from precipitation, surface water runoff, and submarine groundwater discharge. The bays watershed includes a total of 3 million inhabitants, the major urban centers of Miami and Ft. Lauderdale, as well as the Everglades system. With the development of south Florida, the natural diffuse groundwater and stream flow into the bay has been replaced by a large system of canals and levees in an effort to control flooding and drain swampland. The Comprehensive Everglades Restoration Plan includes changes in the freshwater deliveries to Biscayne Bay from point-source discharges via canals to non-point source discharges via wetlands and groundwater flow. The balance of salinity in Biscayne Bay effects sensitive seagrass and tidal ecosystems including numerous species of corals and other biota. A comprehensive understanding of the flow of freshwater into the bay is crucial to future planned developments and restorations. The goal of this study is to use naturally occurring geochemical constituents as tracers to identify and quantify the sources of freshwater, i.e. rainfall, canal flow, and groundwater, discharge to Biscayne Bay. In this study, discrete samples of precipitation, canal water, terrestrial groundwater, marine groundwater, and bay surface water are collected monthly and analyzed for the stable isotopes of hydrogen and oxygen as well as for major cations and anions. Initial results indicate that fresh groundwater has an isotopic signature (del 18O = -2.66 per mil, del D, -7.60 per mil) similar to rainfall (del 18O = -2.86 per mil, del D =-4.78 per mil). In contrast canal water has a heavy isotopic signature (del 18O = -0.46 per mil, del D = -2.48 per mil) due to evaporation. Thus it is possible to use stable isotopes of oxygen and hydrogen to separate canal water from

  2. Radon as a natural geochemical tracer for study of groundwater discharge into lakes

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Axel

    2008-06-27

    In the presented work the suitability of the naturally occurring radioactive noble gas isotope radon-222 for qualitative and quantitative description of groundwater discharge into lakes was studied. Basis of these investigations was the development of two innovative techniques for the on-site determination of radon in water. In the ex-situ radon measurement procedure, water from the source concerned is taken up in an exchange cell used for this purpose. Inside this cell, the radon dissolved in water is transferred via diffusion into a closed counter-flow of air and subsequently detected by a radon-in-air monitor. Where the in-situ radon determination is concerned, a module composed of a semipermeable membrane is introduced into a water column. Subsequently, the radon dissolved in the water body diffuses through the membrane into the corresponding air flow, by means of which it is transferred into a radon-in-air monitor and is detected. Combination of the developed mobile radon extraction techniques with a suitable and portable radon monitor allow the detection of radon-222 with sufficient accuracy (smaller 20 %) in groundwater as well as in surface waters, i.e., within a broad range of concentrations. Radon-222 was subsequently used to characterize groundwater discharge into a meromictic and a dimictic lake, i.e. two types of lake basically distinct from each other with respect to their water circulation properties were investigated. The use of the noble gas isotope radon-222 as a geochemical tracer makes the application of on-site detection techniques possible and that this in turn permits a rapid, reliable, and cost-effective assessment of groundwater discharge rates into lake water bodies.

  3. Chlorine isotopes potential as geo-chemical tracers

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Pradhan, U.K.; Banerjee, R.

    The potential of chlorine isotopes as tracers of geo-chemical processes of earth and the oceans is highlighted based on systematic studies carried out in understanding the chlorine isotope fractionation mechanism, its constancy in seawater and its...

  4. Uranium-series radionuclides as tracers of geochemical processes in Long Island Sound. [Natural /sup 210/Pb tracer study of estuarine geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Benninger, L.K.

    1976-05-01

    An estuary can be visualized as a membrane between land and the deep ocean, and the understanding of the estuarine processes which determine the permeability of this membrane to terrigenous materials is necessary for the estimation of fluxes of these materials to the oceans. Natural radionuclides are useful probes into estuarine geochemistry because of the time-dependent relationships among them and because, as analogs of stable elements, they are much less subject to contamination during sampling and analysis. In this study the flux of heavy metals through Long Island Sound is considered in light of the material balance for excess /sup 210/Pb, and analyses of concurrent seston and water samples from central Long Island Sound are used to probe the internal workings of the estuary.

  5. Testing fundamentals: The chemical state of geochemical tracers in biominerals.

    Science.gov (United States)

    Branson, O.; Redfern, S. A. T.; Read, E.; Elderfield, H.

    2015-12-01

    The use of many carbonate-derived geochemical proxies is underpinned by the assumption that tracer elements are incorporated 'ideally' as impurities the mineral lattice, following relatively straightforward kinetic and thermodynamic drives. This allows comparison to inorganic precipitation experiments, and provides a systematic starting point from which to translate geochemical tracers to environmental records. Biomineral carbonates are a prominent source of geochemical proxy material, and are far from an ideal inorganic system. They are structurally and compositionally heterogeneous mineral-organic composites, produced in tightly controlled biological environments, possibly via non-classical crystal growth mechanisms. Biominerals offer numerous opportunities for tracers to be incorporated in a 'non-ideal' state. For instance, tracers could be hosted within the organic component of the structure, in interstitial micro-domains of a separate mineral phase, or in localized high-impurity clusters. If a proxy element is hosted in a non-ideal state, our understanding of its incorporation and preservation is flawed, and the theoretical basis behind the proxies derived from it must be reevaluated. Thus far, the assumption of ideal tracer incorporation has remained largely untested, owing to the spatial resolution and sensitivity limits of available techniques. Developments in high-resolution, high-sensitivity X-ray spectroscopy at Scanning Transmission X-Ray Microscopes (STXMs) have allowed us to measure trace element coordination in foraminiferal calcite, at length-scales relevant to biomineralisation processes and tracer incorporation. This instrument has allowed us to test the fundamental assumptions behind several geochemical proxy elements. We present a summary of four STXM studies, assessing the chemical state and distribution of Mg (Branson et al, 2014), B (Branson et al, 2015), S and Na (unpub.), and highlight the implications of these data for the use of these

  6. Geochemical tracers to evaluate hydrogeologic controls on river salinization.

    Science.gov (United States)

    Moore, Stephanie J; Bassett, R L; Liu, Beiling; Wolf, Christopher P; Doremus, Dale

    2008-01-01

    The salinization of rivers, as indicated by salinity increases in the downstream direction, is characteristic of arid and semiarid regions throughout the world. Historically, salinity increases have been attributed to various mechanisms, including (1) evaporation and concentration during reservoir storage, irrigation, and subsequent reuse; (2) displacement of shallow saline ground water during irrigation; (3) erosion and dissolution of natural deposits; and/or (4) inflow of deep saline and/or geothermal ground water (ground water with elevated water temperature). In this study, investigation of salinity issues focused on identification of relative salinity contributions from anthropogenic and natural sources in the Lower Rio Grande in the New Mexico-Texas border region. Based on the conceptual model of the system, the various sources of water and, therefore, salinity to the Lower Rio Grande were identified, and a sampling plan was designed to characterize these sources. Analysis results for boron (delta(11)B), sulfur (delta(34)S), oxygen (delta(18)O), hydrogen (delta(2)H), and strontium ((87)Sr/(86)Sr) isotopes, as well as basic chemical data, confirmed the hypothesis that the dominant salinity contributions are from deep ground water inflow to the Rio Grande. The stable isotopic ratios identified the deep ground water inflow as distinctive, with characteristic isotopic signatures. These analyses indicate that it is not possible to reproduce the observed salinization by evapotranspiration and agricultural processes alone. This investigation further confirms that proper application of multiple isotopic and geochemical tracers can be used to identify and constrain multiple sources of solutes in complex river systems.

  7. Natural tracer profiles across argillaceous formations

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, Martin, E-mail: mazurek@geo.unibe.ch [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Alt-Epping, Peter [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Bath, Adrian [Intellisci, Willoughby on the Wolds, Loughborough LE12 6SZ (United Kingdom); Gimmi, Thomas [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland)] [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Niklaus Waber, H. [Rock-Water Interaction, Institute of Geological Sciences, University of Bern (Switzerland); Buschaert, Stephane [Andra, Parc de la Croix Blanche, 92298 Chatenay-Malabry Cedex (France); Canniere, Pierre De; Craen, Mieke De [SCK-CEN, 2400 Mol (Belgium); Gautschi, Andreas [Nagra, 5430 Wettingen (Switzerland); Savoye, Sebastien [IRSN, 92262 Fontenay-aux-Roses Cedex (France); Vinsot, Agnes [Andra, Parc de la Croix Blanche, 92298 Chatenay-Malabry Cedex (France); Wemaere, Isabelle [SCK-CEN, 2400 Mol (Belgium); Wouters, Laurent [Ondraf/Niras, 1210 Brussels (Belgium)

    2011-07-15

    Highlights: > Solute transport processes in clay and shale formations at nine sites are examined. > Conservative pore-water tracers (e.g. Cl{sup -}, {delta}{sup 18}O, {delta}{sup 2}H, He) show regular profiles. > These indicate the dominance of diffusive transport over times of 10{sup 5}-10{sup 6} years. > The contribution of vertical advection to transport is limited or negligible. > Modelled evolution times are in line with independent palaeo-hydrogeological data. - Abstract: Argillaceous formations generally act as aquitards because of their low hydraulic conductivities. This property, together with the large retention capacity of clays for cationic contaminants, has brought argillaceous formations into focus as potential host rocks for the geological disposal of radioactive and other waste. In several countries, programmes are under way to characterise the detailed transport properties of such formations at depth. In this context, the interpretation of profiles of natural tracers in pore waters across the formations can give valuable information about the large-scale and long-term transport behaviour of these formations. Here, tracer-profile data, obtained by various methods of pore-water extraction for nine sites in central Europe, are compiled. Data at each site comprise some or all of the conservative tracers: anions (Cl{sup -}, Br{sup -}), water isotopes ({delta}{sup 18}O, {delta}{sup 2}H) and noble gases (mainly He). Based on a careful evaluation of the palaeo-hydrogeological evolution at each site, model scenarios are derived for initial and boundary pore-water compositions and an attempt is made to numerically reproduce the observed tracer distributions in a consistent way for all tracers and sites, using transport parameters derived from laboratory or in situ tests. The comprehensive results from this project have been reported in . Here the results for three sites are presented in detail, but the conclusions are based on model interpretations of the

  8. Understanding catchment scale sediment sources using geochemical tracers

    Science.gov (United States)

    Ferreira, Carla S. S.; Walsh, Rory P. D.; Shakesby, Richard A.; Steenhuis, Tammo S.; Ferreira, António J. D.; Coelho, Celeste O. A.

    2013-04-01

    It is well-established that urbanization leads to increased erosion (at least locally) as well as enhanced overland flow and streamflow peaks. Less is known about how the spatial distribution of erosion sources and scale of increases in erosion vary with the nature of urbanization in different climatic and socio-economic settings. This is important in order to prevent or reduce adverse impacts of erosion on downstream sedimentation, channel siltation and shifting, and river pollution. This paper adopts a sediment fingerprinting approach to assess the impact of partial urbanization and associated land-use change on sediment sources within a peri-urban catchment (6 km2), Ribeira dos Covões on the outskirts of the city of Coimbra in central Portugal. Urban land-use has increased from just 6% in 1958 to 30% in 2009. The urban pattern includes some well-defined urban residential centres, but also areas of discontinuous urban sprawl, including educational, health and small industrial facilities, numerous new roads and an enterprise park is under construction on the upper part of the catchment. The catchment has a wet Mediterranean climate and the lithology comprises sandstone in the west and limestone in the east. Soil depth is generally >40cm. The average slope angle is 8° (maximum 47°). Altitude ranges from 30m to 205m. A sediment fingerprinting approach was adopted to help establish the relative importance of sediment inputs from different urban areas. During September 2012 current bed-sediment samples (0-3 cm depth) were collected from 11 channel sites along the main stream and in different tributaries. At sites where bed-sediment was deeper, additional samples were taken at 3cm intervals to a maximum depth of around 42cm. In addition, overbank sediment samples (0-3cm depth) were collected at 11 locations around the catchment. All samples were oven-dried (at 38°C) and different particle size fractions (0.125-2mm, 0.063-0.125mm and chemical elements analysed

  9. Combined geophysical and geochemical tracer techniques to assess rates and impact of submarine groundwater discharge into Tampa Bay, Florida

    Science.gov (United States)

    Swarzenski, P. W.; Baskaran, M.; Reich, C.; Greenwood, J.

    2006-12-01

    It is now widely accepted that water and constituent transport by submarine groundwater discharge (SGD) can be ecologically important within some coastal environments. However, the nature of this discharge, which can exhibit tremendously temporal and spatial heterogeneity, renders SGD most often difficult to identify and quantify. U/Th series geochemical tracers and new geophysical tools have been developed that now can yield system-wide information on SGD rates and processes. The objective of this study was to apply naturally- occurring Ra and Rn isotopes to derive SGD rates bay wide, and then examine to the geologic controls on SGD in this system with streaming and time series resistivity measurements. Submarine groundwater discharge rates calculated using a mass balance of excess Ra-226 ranged from 2 to 14 L per square-m per d. When extrapolated to the total shoreline length of the bay, such SGD rates ranged from 2 to 10 cubic-m per d per m of shoreline. High-resolution time series and streaming resistivity measurements confirm that SGD within Tampa Bay can be separated into a near-shore and mid-bay component that involve different water masses and unique mixing processes. SGD-derived nutrient loading estimates in Tampa bay will be compared to similar riverine estimates.

  10. Ternary geochemical-tracing system in natural gas accumulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The establishment of geochemical-tracing system of gas generation and accumulation is helpful to re-elucidating the gas migration and accumulation in time and space. To deduce the complex process of gas accumulation, a ternary geochemical-tracing system is set up, according to stable isotope inheritance of source rocks, kinetic fractionation of stable isotopes, time-accumulating effect of noble gas isotopes, mantle-derived volatile inheritance, and organic molecule inheritance of light hydrocarbons and thermally kinetic fractionation in their generation, in combination with the previous achievements of gas geochemistry and geochemical parameters of gas-source correlation. There are tight interactions for the geochemical parameters with much information about parent inheritance and special biomarkers, in which they are confirmed each other, reciprocally associated and preferentially used for the requirement so that we can use these geochemical parameters to effectively demonstrate the sources of natural gas, sedimentary environments and thermal evolution of source rocks, migration and accumulation of natural gas, and rearrangement of natural gas reservoirs. It is necessary for the ternary geochemical-tracing system to predict the formation of high efficient gas reservoir and their distribution in time and space.

  11. Natural organic compounds as tracers for biomass combustion in aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Simoneit, B.R.T. [Brookhaven National Lab., Upton, NY (United States)]|[Oregon State Univ., Corvallis, OR (United States). Coll. of Oceanic and Atmospheric Sciences; Abas, M.R. bin [Brookhaven National Lab., Upton, NY (United States)]|[Univ. of Malaya, Kuala Lumpur (Malaysia); Cass, G.R. [Brookhaven National Lab., Upton, NY (United States)]|[California Inst. of Tech., Pasadena, CA (United States). Environmental Engineering Science Dept.; Rogge, W.F. [Brookhaven National Lab., Upton, NY (United States)]|[Florida International Univ., University Park, FL (United States). Dept. of Civil and Environmental Engineering; Mazurek, M.A. [Brookhaven National Lab., Upton, NY (United States); Standley, L.J. [Academy of Natural Sciences, Avondale, PA (United States). Stroud Water Research Center; Hildemann, L.M. [Stanford Univ., CA (United States). Dept. of Civil Engineering

    1995-08-01

    Biomass combustion is an important primary source of carbonaceous particles in the global atmosphere. Although various molecular markers have already been proposed for this process, additional specific organic tracers need to be characterized. The injection of natural product organic tracers to smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature. The degree of alteration increases as the burn temperature rises and the moisture content of the fuel decreases. Although the molecular composition of organic matter in smoke particles is highly variable, the molecular structures of the tracers are generally source specific. The homologous compound series and biomarkers present in smoke particles are derived directly from plant wax, gum and resin by volatilization and secondarily from pyrolysis of biopolymers, wax, gum and resin. The complexity of the organic components of smoke aerosol is illustrated with examples from controlled burns of temperate and tropical biomass fuels. Burning of biomass from temperate regions (i.e., conifers) yields characteristic tracers from diterpenoids as well as phenolics and other oxygenated species, which are recognizable in urban airsheds. The major organic components of smoke particles from tropical biomass are straight-chain, aliphatic and oxygenated compounds and triterpenoids. The precursor-to-product approach of organic geochemistry can be applied successfully to provide tracers for studying smoke plume chemistry and dispersion.

  12. Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater.

    Science.gov (United States)

    Kloppmann, Wolfram; Vengosh, Avner; Guerrot, Catherine; Millot, Romain; Pankratov, Irena

    2008-07-01

    A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

  13. Fingerprinting captured CO2 using natural tracers: Determining CO2 fate and proving ownership

    Science.gov (United States)

    Flude, Stephanie; Gilfillan, Stuart; Johnston, Gareth; Stuart, Finlay; Haszeldine, Stuart

    2016-04-01

    In the long term, captured CO2 will most likely be stored in large saline formations and it is highly likely that CO2 from multiple operators will be injected into a single saline formation. Understanding CO2 behavior within the reservoir is vital for making operational decisions and often uses geochemical techniques. Furthermore, in the event of a CO2 leak, being able to identify the owner of the CO2 is of vital importance in terms of liability and remediation. Addition of geochemical tracers to the CO2 stream is an effective way of tagging the CO2 from different power stations, but may become prohibitively expensive at large scale storage sites. Here we present results from a project assessing whether the natural isotopic composition (C, O and noble gas isotopes) of captured CO2 is sufficient to distinguish CO2 captured using different technologies and from different fuel sources, from likely baseline conditions. Results include analytical measurements of CO2 captured from a number of different CO2 capture plants and a comprehensive literature review of the known and hypothetical isotopic compositions of captured CO2 and baseline conditions. Key findings from the literature review suggest that the carbon isotope composition will be most strongly controlled by that of the feedstock, but significant fractionation is possible during the capture process; oxygen isotopes are likely to be controlled by the isotopic composition of any water used in either the industrial process or the capture technology; and noble gases concentrations will likely be controlled by the capture technique employed. Preliminary analytical results are in agreement with these predictions. Comparison with summaries of likely storage reservoir baseline and shallow or surface leakage reservoir baseline data suggests that C-isotopes are likely to be valuable tracers of CO2 in the storage reservoir, while noble gases may be particularly valuable as tracers of potential leakage.

  14. Fingerprinting Captured CO2 Using Natural Tracers for CCS Monitoring and Verification

    Science.gov (United States)

    Flude, S.; Gilfillan, S.; Johnson, G.; Gyore, D.; Haszeldine, S.; Stuart, F. M.

    2015-12-01

    In the long term, captured CO2 will most likely be stored in large saline formations and it is highly likely that CO2 from multiple operators will be injected into a single saline formation. Understanding CO2 behaviour within the reservoir is vital for making operational decisions and often uses geochemical techniques. Furthermore, in the event of a CO2 leak, being able to identify the owner of the CO2 is of vital importance in terms of liability and remediation. Addition of geochemical tracers to the CO2 stream is an effective way of tagging the CO2 from different operators, but may become prohibitively expensive at large scale storage sites. Here we present results from a project assessing whether the natural isotopic composition (C, O and noble gas isotopes) of captured CO2 is sufficient to distinguish CO2 captured using different technologies and from different fuel sources from each other and from likely baseline conditions. Results include analytical measurements of CO2 sampled from a number of different CO2 capture plants and a comprehensive literature review of the known and hypothetical isotopic compositions of captured CO2 and baseline conditions. Key findings from the literature review suggest that the carbon isotope composition will be most strongly controlled by that of the feedstock, but significant fractionation is possible during the capture process; oxygen isotopes are likely to be controlled by the isotopic composition of any water used in either the industrial process or the capture technology; and noble gases concentrations will likely be controlled by the capture technique employed. Preliminary analytical results are in agreement with these predictions. Comparison with summaries of likely storage reservoir baseline data and shallow or surface leakage reservoir baseline data suggests that C-isotopes are likely to be valuable tracers of CO2 in the storage reservoir, while noble gases may be particularly valuable as tracers of potential leakage.

  15. Geochemical fine-sediment tracers in San Francisco Bay and its outer coast: the role of local watersheds

    Science.gov (United States)

    Takesue, R. K.; Barnard, P. L.

    2012-12-01

    enriched in both light and heavy REENASC. Fine sediment in Alameda Creek was very similar to average sedimentary rock (shale) and therefore had no distinctive characteristics. Because the underlying geology is quite diverse, the fine-sediment compositions of the Sacramento and San Joaquin Rivers and local tributaries are in many cases geochemically distinct. Geochemical tracers suggest that fine sediment similar in composition to that in Petaluma/Sonoma tributaries was transported up-estuary into Suisun Bay during flood tide where it was deposited on mudflats. Fine sediment characteristic of the Sacramento River was found throughout SFB, including lower South Bay and the outer coast, while that of the San Joaquin River was not observed downstream of Carquinez Strait. In contrast, Napa River, Coyote Creek, and San Francisquito Creek appeared to contribute little to the sediment budget of SFB. Fine sediment on the outer coast was enriched in elements associated with heavy minerals, likely derived locally from granitic outcrops at Point Reyes and Montara Mountain. The relative uniformity of fine-sediment compositions in San Pablo and South Bays suggests a high degree of mud resuspension and redistribution. Any sediment management decisions should take into account the dynamic nature of the seabed in these subembayments.

  16. An investigation of radial tracer flow in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Jetzabeth, Ramirez-Sabag; Fernando, Samaniego V.; Jesus, Rivera R.; Fernando Rodriguez

    1991-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile region where longitudinal dispersion and convection take place and a stagnant region where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared to those previously presented in literature by Moench and Ogata, Tang et al., Chen et al., and Hsieh et al. The solution is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., for short times) was carried out. The influence of various dimensionless parameters that enter into the solution was investigated. A discussion of results obtained through the Crump and Stehfest algorithm is presented, concluding that the Crump method provides more reliable tracer concentrations.

  17. Radon-222 and beryllium-7 as natural tracer; Radon-222 und Beryllium-7 als natuerliche Tracer

    Energy Technology Data Exchange (ETDEWEB)

    Frank, G.; Steinkopff, T. [Deutscher Wetterdienst, Offenbach (Germany). Radioaktivitaetsueberwachung; Salvamoser, J. [Institut fuer Angewandte Isotopen-, Gas- und Umweltuntersuchungen (IGU), Woerthsee (Germany)

    2016-07-01

    The Global Atmosphere Watch Program (GAW) is intended to analyse worldwide the influence of anthropogenic emissions to the atmosphere. Data are continuously transferred to the ''World Data Centre for Green House Gases'' of the WMO. For the study of atmospheric transports the natural radionuclides Rn-222, Be-7, Pb-210, Pb- 214 and Bi-214 are continuously measured at the Umweltforschungsstation Schneefernerhaus (2650 m) and at the Zugspitze (2962 m) by the Deutscher Wetterdienst (DWD, German Weather Service). The measurements support the classification of atmospheric transport, atmospheric dilution and dispersion models of gaseous and aerosol bond micro pollutants. Results are carried out in combination with meteorological data. It is shown the optimization and effect of a new sampling site for the measurement of Rn-222 activity at the Zugspitze. Results of Rn-222 and Be-7 concentrations are shown in relation to horizontal and vertical dispersion of air masses. The origin of natural Rn-222 and Be-7 are known, therefore both nuclides are well suited for the research of atmospheric transport. Rn-222 is an ideal tracer, because there is no influence by atmospheric processes (chemical processes, wash out effects).

  18. Groundwater surface water interaction study using natural isotopes tracer

    Science.gov (United States)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for δ 18O value, while the δD value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  19. Identifying Groundwater Discharge Sources and Associated Geochemical Influences Using Resistivity Imaging and Geochemical Tracers in a Semi-Arid Estuary in South Texas

    Science.gov (United States)

    Douglas, A. R.; Murgulet, D.; Spalt, N.

    2015-12-01

    The Nueces Bay (NB) system has been found to be ecologically unsound due to the loss/alteration of habitat and flow regimes required by indicator species and compromised nutrient cycling and sediment loading. The management practices of freshwater inflow regimes to NB concentrates on surface water flows and does not account for groundwater inflows, though submarine groundwater discharge (SGD) has been identified as a source of freshwater and limiting nutrients that could significantly impact bay salinities and nutrient loading. To encompass the range of spatio-temporal variabilities occurring between groundwater (GW) and surface-water (SW), multiple methods, including resistivity imaging, geochemical tracers, and radioisotopes, are applied in conjunction to identify SGD sources. Preliminary continuous resistivity profile surveys identified multiple possible GW upwelling paths from which thirteen stations were chosen in NB and two stations in Nueces River (NR). A Principal Component Analysis (PCA) of initial geochemical, nutrient and radioisotope data, shows that 76% of the variation in the data is explained by three factors: seasonality, freshwater inflows, and reducing environment. Significant seasonal variation is seen in average SW salinity (37psu in September 2014 to 4psu in June 2015), Ra-224 (359dpm/L in September to 636dpm/L in December), Ra-226 (268dpm/L in September to 570 dpm/L in December), ammonium (1.3μM in September to 5.5μM in April), and chlorophyll-α (3.99μg/L in December to 12.3 μg/L in April). Additionally, short-lived radioisotopes Rn-222 and Ra-224 are consistently elevated near the NR mouth, the inflow from Gum Hollow Creek, and a single station in the middle of the Bay indicating more localized, active SGD sources. However, only the stations in NR and at the NR mouth show consistently strong correlations to chlorophyll-α, phosphate, and silicate, with the river station closest to NB having the highest concentrations of nitrogen

  20. A three-component hydrograph separation based on geochemical tracers in a tropical mountainous headwater catchment in northern Thailand

    Science.gov (United States)

    Hugenschmidt, C.; Ingwersen, J.; Sangchan, W.; Sukvanachaikul, Y.; Duffner, A.; Uhlenbrook, S.; Streck, T.

    2014-02-01

    Land-use change in the mountainous parts of northern Thailand is reflected by an increased application of agrochemicals, which may be lost to surface and groundwater. The close relation between flow paths and contaminant transport within hydrological systems requires recognizing and understanding the dominant hydrological processes. To date, the vast majority of studies on runoff generation have been conducted in temperate regions. Tropical regions suffer from a general lack of data, and little is known about runoff generation processes. To fill this knowledge gap, a three-component hydrograph separation based on geochemical tracers was carried out in a steep, remote and monsoon-dominated study site (7 km2) in northern Thailand. Silica and electrical conductivity (EC) were identified as useful tracers and were applied to calculate the fractions of groundwater (similar to pre-event water), shallow subsurface flow and surface runoff on stormflow. K+ was a useful indicator for surface runoff dynamics, and Ca2+ provided insights into groundwater behaviour. Nevertheless, neither measure was applicable for the quantification of runoff components. Cl- and further parameters (e.g. Na+, K+, and Mg2+) were also not helpful for flow path identification, nor were their concentrations distinguishable among the components. Groundwater contributed the largest fractions to stormflow (62-80%) throughout all events, followed by shallow subsurface flow (17-36%) and surface runoff (2-13%). Our results provide important insights into the dynamics of the runoff processes in the study area and may be used to assess the transport pattern of contaminants (i.e. agrochemicals) here.

  1. Use of geochemical tracers for estimating groundwater influxes to the Big Sioux River, eastern South Dakota, USA

    Science.gov (United States)

    Neupane, Ram P.; Mehan, Sushant; Kumar, Sandeep

    2017-09-01

    Understanding the spatial distribution and variability of geochemical tracers is crucial for estimating groundwater influxes into a river and can contribute to better future water management strategies. Because of the much higher radon (222Rn) activities in groundwater compared to river water, 222Rn was used as the main tracer to estimate groundwater influxes to river discharge over a 323-km distance of the Big Sioux River, eastern South Dakota, USA; these influx estimates were compared to the estimates using Cl- concentrations. In the reaches overall, groundwater influxes using the 222Rn activity approach ranged between 0.3 and 6.4 m3/m/day (mean 1.8 m3/m/day) and the cumulative groundwater influx estimated during the study period was 3,982-146,594 m3/day (mean 40,568 m3/day), accounting for 0.2-41.9% (mean 12.5%) of the total river flow rate. The mean groundwater influx derived using the 222Rn activity approach was lower than that calculated based on Cl- concentration (35.6 m3/m/day) for most of the reaches. Based on the Cl- approach, groundwater accounted for 37.3% of the total river flow rate. The difference between the method estimates may be associated with minimal differences between groundwater and river Cl- concentrations. These assessments will provide a better understanding of estimates used for the allocation of water resources to sustain agricultural productivity in the basin. However, a more detailed sampling program is necessary for accurate influx estimation, and also to understand the influence of seasonal variation on groundwater influxes into the basin.

  2. Geochemical Speciation of Soil 7Be,137Cs,226Ra and 228Ra as Tracers to Particle Trnsport

    Institute of Scientific and Technical Information of China (English)

    BALZHANGUO; WANGUOJIANG; 等

    1997-01-01

    A brunisolic soil collected from an erosive forest land(HF-1-1) and a yellow soil from and accumulative shallow basin(HF-6-1) in the watershed of Lake Hongfeng (HF) were used for activity measurements of 7Be,137Cs,226Ra and 228Ra in different geochemical speciation.More than 85% of 7Be,137Cs,226Ra and 228Ra in the soils were bound to organic Fe-Mn oxy-hydroxide and residual fractions.They could move with soil particlesw and be used as tracers for the erosion and /or accumulation of soil particles.7Be gohemical specition in the soils agreed with its trace for seasonal particle transport.137Cs geohemial speciaiton was suitable for tracing soil particle accumulation and for sediment aating.226Ra and 228Ra were ombined in crystalline skeleton of clay minerals and mainly remained as residues in the soils and little was bound to the soluble,exchangeable and carbonate fractions.The differentiation of 226 Ra/228Ra activity ratios in different geoheical fractions in the soils could be used as a parameter to trace accumulation and /or erosion of soil particles.

  3. Understanding sediment sources in a peri-urban Mediterranean catchment using geochemical tracers

    Science.gov (United States)

    Ferreira, Carla; Walsh, Rory; Kikuchi, Ryunosuke; Blake, Will

    2016-04-01

    geochemical properties of bed-sediments. Catchment outlet sediment collected after the summer and a storm of high rainfall intensity following dry weather displayed geochemical properties closer to those of sediment from sandstone sub-catchments, and in particularly sediment from the enterprise park under construction. After the storm that followed very wet weather, however, limestone areas became of much greater significance as sediment sources, probably because of the high soil saturation. At limestone stream sites receiving runoff from the newly constructed road, fine bed-sediment geochemistry was found to be similar to that of road sediment, indicating a high contribution of this source. These results are supported by spatio-temporal differences in streamflow and suspended sediment concentrations at instrumented monitoring stations. It is concluded that this methodology represents a potentially useful tool to enable river managers to detect and assess sediment sources in urbanized and partly urbanized catchments, and to supporting them in designing and implementing effective land-use mosaics and site-specific measures to mitigate erosion.

  4. Chemical and isotopic provenance tracers in ancient copper and bronze artifacts: a geochemical database of copper mines

    Science.gov (United States)

    Giunti, I.; Artioli, G.; Giussani, B.; Marelli, M.; Recchia, S.; Angelini, I.; Baumgarten, B.; Omenetto, P.; Villa, I. M.

    2009-04-01

    The provenance of ore minerals used in prehistoric and historic times for copper smelting and extraction is one of the basic questions that archaeologists pose to modern analytical archaeometry [1]. To aid metal provenancing studies, a database of fully characterized Alpine copper mineralisations is being developed as the fundamental reference frame for metal extraction and diffusion in the past. In the early stages of the project, some of the most well known copper deposits in the Western Alps were selected and compared with very different minerogenetic deposits from the French Queyras (Saint Veran) and the Ligurian Apennines (Libiola, Monte Loreto). The fully characterized samples were then analysed by ICP-QMS (inductively coupled plasma-quadrupolar mass spectrometry). The abundances of about 60 minor and trace elements, including most transition metals and chalcophile elements, and the rare earths were measured in all samples. Furthermore, the feasibility of the routine reliable measurement of the 65Cu/63Cu isotope ratio [2] and its eventual use as a possible ore tracer was tested. Multicollector ICP-Mass Spectrometry was used to determine precise Pb isotopic ratios (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) and is being used for 65Cu/63Cu ratios as well. Advanced strategies based on multivariate analysis were then used to discriminate the ore mineral provenance. Data were treated with the chemometric software "The Unscrambler Version 9.5" (CAMO AS, Trondheim, Norway). Data pre-treatment, PCA [3] and PLS-DA [4,5] models were performed as implemented in the software. The availability of such unprecedented and complete amount of data of Alpine copper deposits also yields information relevant for the geochemical and minerogenetic intepretation of the deposits themselves. Application of PCA and PLS-DA to the geochemical and isotopic database proved to be a very powerful tool to discriminate the ore source areas with very little ambiguity. The applications to

  5. Using multiple geochemical tracers to characterize the hydrogeology of the submarine spring off Crescent Beach, Florida

    Science.gov (United States)

    Swarzenski, P.W.; Reich, C.D.; Spechler, R.M.; Kindinger, J.L.; Moore, W.S.

    2001-01-01

    A spectacular submarine spring is located about 4 km east of Crescent Beach, FL, in the Atlantic Ocean. The single vent feature of Crescent Beach Spring provides a unique opportunity to examine onshore-offshore hydrogeologic processes, as well as point source submarine ground water discharge. The Floridan aquifer system in northeastern Florida consists of Tertiary interspersed limestone and dolomite strata. Impermeable beds confine the water-bearing zones under artesian pressure. Miocene and younger confining strata have been eroded away at the vent feature, enabling direct hydrologic communication of Eocene ground water with coastal bottom waters. The spring water had a salinity of 6.02, which was immediately diluted by ambient seawater during advection/mixing. The concentration of major solutes in spring water and onshore well waters confirm a generalized easterly flow direction of artesian ground water. Nutrient concentrations were generally low in the reducing vent samples, and the majority of the total nitrogen species existed as NH3. The submarine ground water tracers, Rn-222 (1174 dpm I-1, dpm), methane (232 nM) and barium (294.5 nM) were all highly enriched in the spring water relative to ambient seawater. The concentrations of the reverse redox elements U, V and Mo were expectedly low in the submarine waters. The strontium isotope ratio of the vent water (87Sr/86Sr = 0.70798) suggests that the spring water contain an integrated signature indicative of Floridan aquifer system ground water. Additional Sr isotopic ratios from a series of surficial and Lower Floridan well samples suggest dynamic ground water mixing, and do not provide clear evidence for a single hydrogeologic water source at the spring vent. In this karst-dominated aquifer, such energetic mixing at the vent feature is expected, and would be facilitated by conduit and fractured flow. Radium isotope activities were utilized to estimate flow-path trajectories and to provide information on

  6. Reactive surface area in geochemical models - Lessons learned from a natural analogue

    NARCIS (Netherlands)

    Koenen, M.; Wasch, L.J.

    2013-01-01

    Many uncertainties exist in geochemical modeling. Mineral reactive surface area is one of the uncertain parameters. QEMSCAN analyses are performed on sandstone samples from a Dutch CO2 natural analogue to determine reactive surface areas. Geochemical modeling is performed using QEMSCAN surface areas

  7. Significant Groundwater Discharge of Nutrients to Western Long Island Sound Inferred From Radioisotope, Nutrient and Organic Geochemical Tracers

    Science.gov (United States)

    Crusius, J.; Kroeger, K. D.; Zhang, P.; Zhao, S.; Bratton, J. F.; Bokuniewicz, H.; Coffey, R.; Green, A.; Baldwin, S.; Erban, L.; Casso, M.

    2008-12-01

    Western Long Island Sound suffers from seasonal oxygen depletion due to both nutrient loading in this heavily populated region as well as restricted circulation of the Sound. The role played by groundwater in delivering nutrients to the Sound is not well understood, which served as motivation for the sampling we initiated in May, 2008. Work was carried out in both Manhasset Bay, a portion of which is sewered, and Northport Harbor, which is largely unsewered. There is clear evidence of discharge of groundwater to each embayment, as reflected in surface-water Rn-222 time series, seepage meter and high-resolution piezometer transects installed perpendicular to shore). Seepage rates were as high as 32 cm/day and modulated by the tide. Initial data reveal variable groundwater total DIN concentrations, spanning similar concentration ranges (as high as 500 uM), in the sewered and unsewered locations. Concentrations of organic geochemical tracers of sewage (including caffeine and imidacloprid) are high in samples with high nutrient concentrations and also span comparable ranges in sewered and unsewered locations. A preliminary interpretation of these results would suggest that most of the nutrient flux from groundwater is from wastewater in both the sewered and unsewered settings (rather than from fertilizer application, atmospheric deposition, etc.), implying that the sewering is not very effective. If this result is verified with additional sampling this fall, it would suggest that wastewater-influenced groundwater discharge is indeed a prominent source of nutrients to western Long Island Sound which in turn contributes to eutrophication and oxygen depletion.

  8. Characterization of hydraulic fractures and reservoir properties of shale using natural tracers

    Science.gov (United States)

    Heath, J. E.; Gardner, P.; Kuhlman, K. L.; Malama, B.

    2013-12-01

    Hydraulic fracturing plays a major role in the economic production of hydrocarbon from shale. Current fracture characterization techniques are limited in diagnosing the transport properties of the fractures on the near wellbore scale to that of the entire stimulated reservoir volume. Microseismic reveals information on fracture geometries, but not transport properties. Production analysis (e.g., rate transient analysis using produced fluids) estimates fracture and reservoir flow characteristics, but often relies on simplified models in terms of fracture geometries and fluid storage and transport. We present the approach and potential benefits of incorporating natural tracers with production data analysis for fracture and reservoir characterization. Hydraulic fracturing releases omnipresent natural tracers that accumulate in low permeability rocks over geologic time (e.g., radiogenic 4He and 40Ar). Key reservoir characteristics govern the tracer release, which include: the number, connectivity, and geometry of fractures; the distribution of fracture-surface-area to matrix-block-volume; and the nature of hydrocarbon phases within the reservoir (e.g., methane dissolved in groundwater or present as a separate gas phase). We explore natural tracer systematics using numerical techniques under relevant shale-reservoir conditions. We evaluate the impact on natural tracer transport due to a variety of conceptual models of reservoir-transport properties and boundary conditions. Favorable attributes for analysis of natural tracers include the following: tracer concentrations start with a well-defined initial condition (i.e., equilibrium between matrix and any natural fractures); there is a large suite of tracers that cover a range of at least 7x in diffusion coefficients; and diffusive mass-transfer out of the matrix into hydraulic fractures will cause elemental and isotopic fractionation. Sandia National Laboratories is a multi-program laboratory managed and operated by

  9. Coastal groundwater dynamics off Santa Barbara, California: combining geochemical tracers, electromagnetic seepmeters, and electrical resistivity

    Science.gov (United States)

    Swarzenski, Peter W.; Izbicki, John A.

    2009-01-01

    computed (mol per day per meter of shoreline): NH4+ = 0.06-0.29 mol day-1 m-1; SiO4 = 0.22-0.29 mol day-1 m-1; PO43-= 0.04-0.17 mol day-1 m-1; [NO2- + NO3-] = 0-0.52 mol day-1 m-1; dissolved inorganic nitrogen (DIN) = 0.01-0.17 mol day-1 m-1, and dissolved organic nitrogen (DON) = 0.08-0.09 mol day-1 m-1. Compared to the ephemeral nature of fluvial and marine inputs into this region, such SGD-derived loadings can provide a sustained source of select nutrients to the coastal waters off Santa Barbara, California that should be accounted for in mass balance estimates.

  10. Forced and natural gradient tracer tests in a highly heterogeneous porous aquifer: instrumentation and measurements

    Science.gov (United States)

    Ptak, T.; Teutsch, G.

    1994-07-01

    At the Horkheimer Insel experimental field site, several short to intermediate distance forced and natural gradient tracer tests with depth-integrated and multilevel sampling were conducted to characterize the aquifer transport properties. Compared with other test sites, the aquifer at the Horkheimer Insel is highly heterogeneous and highly conductive. Hence, new tracer measurement techniques had to be developed. This paper presents some of the instrumentation developed together with measurements and their initial interpretation. The results demonstrate that for contaminant transport predictions in highly heterogeneous and highly conductive aquifers, investigation techniques with a high resolution in time and space are needed. The aquifer heterogeneity is evident from the spatial variability of peak concentration, transport velocity and longitudinal macrodispersivity values obtained from the tracer tests. Furthermore, the tracer test results indicate that at the observation scale investigated, a complex numerical flow and transport model is needed to describe adequately mass transport within the heterogeneous aquifer.

  11. Use of geochemical and isotope tracers to assess groundwater dependency of a terrestrial ecosystem: case study from southern Poland

    Science.gov (United States)

    Zurek, Anna J.; Witczak, Stanislaw; Kania, Jaroslaw; Rozanski, Kazimierz; Dulinski, Marek; Wachniew, Przemyslaw

    2015-04-01

    The presented study was aimed at better understanding of the functioning of groundwater dependent terrestrial ecosystem (GDTE) located in the south of Poland. The studied GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Bloto fen). It relies not only on shallow, unconfined aquifer but indirectly also on groundwater originating from the deeper confined aquifer, underlying the Quaternary cover and separated from it by an aquitard of variable thickness. The main objective of the study was to evaluate the contribution of groundwater to the water balance of the studied GDTE and thereby assess the potential risk to this system associated with intense exploitation of the deeper aquifer. The Wielkie Błoto fen area and the adjacent parts of Niepolomice Forest are drained by the Dluga Woda stream with 8.2 km2 of gauged catchment area. Hydrometric measurements, carried out on the Dluga Woda stream over two-year period (August 2011 - August 2013) were supplemented by chemical and isotope analyses of stream water, monitored on monthly basis. Physico-chemical parameters of the stream water (SEC, pH, Na content, Na/Cl molar ratio) and isotope tracers (deuterium, oxygen-18 and tritium) were used to quantify the expected contribution of groundwater seepage from the deeper aquifer to the water balance of the Dluga Woda catchment. The mean transit time of water through the catchment, derived from temporal variations of δ18O and tritium content in the Dluga Woda stream, was in the order of three months. This fast component of the total discharge of Dluga Woda stream is associated surface runoff and groundwater flow paths through the Quaternary cover. The slow component devoid of tritium and probably originated from the deeper Neogene aquifer is equal to approximately 30% of the total discharge. The relationships between the physico-chemical parameters of the stream water and the flow rate of Dluga Woda clearly indicate that the monitored

  12. Radon as a natural tracer for underwater cave exploration.

    Science.gov (United States)

    Csondor, Katalin; Erőss, Anita; Horváth, Ákos; Szieberth, Dénes

    2017-07-01

    The Molnár János cave is one of the largest hypogenic caves of the Buda Thermal Karst (Budapest, Hungary) and mainly characterized by water-filled passages. The major outflow point of the waters of the cave system is the Boltív spring, which feeds the artificial Malom Lake. Previous radon measurements in the cave system and in the spring established the highest radon concentration (71 BqL(-1)) in the springwater. According to previous studies, the origin of radon was identified as iron-hydroxide containing biofilms, which form where there is mixing of cold and thermal waters, and these biofilms efficiently adsorb radium from the thermal water component. Since mixing of waters is responsible for the formation of the cave as well, these iron-hydroxide containing biofilms and the consequent high radon concentrations mark the active cave forming zones. Based on previous radon measurements, it is supposed that the active mixing and cave forming zone has to be close to the spring, since the highest radon concentration was measured there. Therefore radon mapping was carried out with the help of divers in order to get a spatial distribution of radon in the cave passages closest to the spring. Based on our measurements, the highest radon activity concentration (84 BqL(-1)) was found in the springwater. Based on the distribution of radon activity concentrations, direct connection was established between the spring and the István-room of the cave, which was verified by an artificial tracer. However, the distribution of radon in the cave passages shows lower concentrations (18-46 BqL(-1)) compared to the spring, therefore an additional deep inflow from hitherto unknown cave passages is assumed, from which waters with high radon content arrive to the spring. These passages are assumed to be in the active cave formation zone. This study proved that radon activity concentration distribution is a useful tool in underwater cave exploration. Copyright © 2016 Elsevier Ltd. All

  13. Geochemical monitoring using noble gases and carbon isotopes: study of a natural reservoir; Monitoring geochimique par couplage entre les gaz rares et les isotopes du carbone: etude d'un reservoir naturel

    Energy Technology Data Exchange (ETDEWEB)

    Jeandel, E

    2008-12-15

    To limit emissions of greenhouse gases in the atmosphere, CO{sub 2} geological sequestration appears as a solution in the fight against climate change. The development of reliable monitoring tools to ensure the sustainability and the safety of geological storage is a prerequisite for the implementation of such sites. In this framework, a geochemical method using noble gas and carbon isotopes geochemistry has been tested on natural and industrial analogues. The study of natural analogues from different geological settings showed systematic behaviours of the geochemical parameters, depending on the containment sites, and proving the effectiveness of these tools in terms of leak detection and as tracers of the behaviour of CO{sub 2}. Moreover, an experience of geochemical tracing on a natural gas storage has demonstrated that it is possible to identify the physical-chemical processes taking place in the reservoir to a human time scale, increasing interest in the proposed tool and providing general information on its use. (author)

  14. Development of Radon-222 as Natural Tracer for Monitoring the Remediation of NAPL in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Brian M. Davis; Lewis Semprini; Jonathan Istok

    2003-02-27

    Naturally occurring 222-radon in ground water can potentially be used as an in situ partitioning tracer to characterize dense nonaqueous phase liquid (DNAPL) saturations. The static method involves comparing radon concentrations in water samples from DNAPL-contaminated and non-contaminated portions of an aquifer. During a push-pull test, a known volume of test solution (radon-free water containing a conservation tracer) is first injected (''pushed'') into a well; flow is then reversed and the test solution/groundwater mixture is extracted (''pulled'') from the same well. In the presence of NAPL radon transport is retarded relative to the conservative tracer. Assuming linear equilibrium partitioning, retardation factors for radon can be used to estimate NAPL saturations.The utility of this methodology was evaluated in laboratory and field settings.

  15. Natural and Artificial (fluorescent) Tracers to Characterise Hydrogeological Functioning and to Protect Karst Aquifers

    Science.gov (United States)

    Andreo, B.; Mudarra, M.; Marin, A. I.; Barberá, J. A.

    2012-12-01

    The hydrogeological functioning and response of karst aquifers can be determined by the joint use of natural hydrogeochemical tracers, especially total organic carbon (TOC) and intrinsic fluorescence of water, together with artificial (fluorescent) tracers, under the same hydrodynamic conditions. Sharp and rapid variations in discharge, temperature, electrical conductivity and water chemistry, particularly of natural tracers of infiltration (TOC, intrinsic fluorescence and NO3-) recorded in karst spring water, confirm the existence of well developed karst conduits in the sector of the aquifer being drained, with rapid flows and very short water transit times from the surface to the springs (Mudarra et al., 2011). This is in agreement with the evidence obtained from breakthrough curves of fluorescent dye tracers (uranine, eosine, etc.). However, time lags between maximum concentrations of natural (especially TOC and intrinsic fluorescence) and artificial tracers show that the global system response is faster than that produced from a recharge concentrated at a point on the surface, even in karst sinkholes. Response and transit times of water through the karst can be calculated using both natural and artificial tracers, but flow velocities can really only be quantified using artificial tracers. Analysis of the responses obtained by natural tracers of infiltration (global system response) and artificial tracers (single response) in karst waters has revealed the usefulness and complementarity of both techniques for characterising the hydrogeological functioning of karst aquifers and, even more important, for validating contamination vulnerability mapping in these medium (Zwahlen, 2004; Andreo et al., 2006). In recent decades, several methods have been developed for such vulnerability mapping, but little progress has been made in validating their results. This validation is essential for the adequate protection of water resources in karst media, as has been shown in

  16. Recharge sources and residence times of groundwater as determined by geochemical tracers in the Mayfield Area, southwestern Idaho, 2011–12

    Science.gov (United States)

    Hopkins, Candice B.

    2013-01-01

    Parties proposing residential development in the area of Mayfield, Idaho are seeking a sustainable groundwater supply. During 2011–12, the U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, used geochemical tracers in the Mayfield area to evaluate sources of aquifer recharge and differences in groundwater residence time. Fourteen groundwater wells and one surface-water site were sampled for major ion chemistry, metals, stable isotopes, and age tracers; data collected from this study were used to evaluate the sources of groundwater recharge and groundwater residence times in the area. Major ion chemistry varied along a flow path between deeper wells, suggesting an upgradient source of dilute water, and a downgradient source of more concentrated water with the geochemical signature of the Idaho Batholith. Samples from shallow wells had elevated nutrient concentrations, a more positive oxygen-18 signature, and younger carbon-14 dates than deep wells, suggesting that recharge comes from young precipitation and surface-water infiltration. Samples from deep wells generally had higher concentrations of metals typical of geothermal waters, a more negative oxygen-18 signature, and older carbon-14 values than samples from shallow wells, suggesting that recharge comes from both infiltration of meteoric water and another source. The chemistry of groundwater sampled from deep wells is somewhat similar to the chemistry in geothermal waters, suggesting that geothermal water may be a source of recharge to this aquifer. Results of NETPATH mixing models suggest that geothermal water composes 1–23 percent of water in deep wells. Chlorofluorocarbons were detected in every sample, which indicates that all groundwater samples contain at least a component of young recharge, and that groundwater is derived from multiple recharge sources. Conclusions from this study can be used to further refine conceptual hydrological models of the area.

  17. Extended application of radon as a natural tracer in oil reservoirs

    Directory of Open Access Journals (Sweden)

    Moreira R.M.

    2013-05-01

    Full Text Available In the 80's it was a common practice in the study of contamination by NAPL to incorporate a tracer to the medium to be studied. At that time the first applications focused on the use of 222Rn, a naturally occurring radioactive isotope as a natural tracer, appropriate for thermodynamics studies, geology and transport properties in thermal reservoirs. In 1993 the deficit of radon was used to spot and quantify the contamination by DNAPL under the surface. For the first time these studies showed that radon could be used as a partitioning tracer. A methodology that provides alternatives to quantify the oil volume stored in the porous space of oil reservoirs is under development at CDTN. The methodology here applied, widens up and adapts the knowledge acquired from the use of radon as a tracer to the studies aimed at assessing SOR. It is a postulation of this work that once the radon partition coefficient between oil and water is known, SOR will be determined considering the increased amount of radon in the water phase as compared to the amount initially existent as the reservoir is flooded with water. This paper will present a description of the apparatus used and some preliminary results of the experiments.

  18. Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests

    Science.gov (United States)

    Smith, R.L.; Garabedian, S.P.; Brooks, M.H.

    1996-01-01

    The transport of many solutes in groundwater is dependent upon the relative rates of physical flow and microbial metabolism. Quantifying rates of microbial processes under subsurface conditions is difficult and is most commonly approximated using laboratory studies with aquifer materials. In this study, we measured in situ rates of denitrification in a nitrate- contaminated aquifer using small-scale, natural-gradient tracer tests and compared the results with rates obtained from laboratory incubations with aquifer core material. Activity was measured using the acetylene block technique. For the tracer tests, co-injection of acetylene and bromide into the aquifer produced a 30 ??M increase in nitrous oxide after 10 m of transport (23-30 days). An advection-dispersion transport model was modified to include an acetylene-dependent nitrous oxide production term and used to simulate the tracer breakthrough curves. The model required a 4-day lag period and a relatively low sensitivity to acetylene to match the narrow nitrous oxide breakthrough curves. Estimates of in situ denitrification rates were 0.60 and 1.51 nmol of N2O produced cm-3 aquifer day-1 for two successive tests. Aquifer core material collected from the tracer test site and incubated as mixed slurries in flasks and as intact cores yielded rates that were 1.2-26 times higher than the tracer test rate estimates. Results with the coring-dependent techniques were variable and subject to the small- scale heterogeneity within the aquifer, while the tracer tests integrated the heterogeneity along a flow path, giving a rate estimate that is more applicable to transport at the scale of the aquifer.

  19. An ice-ocean model study to explore climate change mechanisms in comparison with interannual-to-decadal variability of geochemical tracers

    Institute of Scientific and Technical Information of China (English)

    Motoyoshi Ikeda

    2014-01-01

    One way to identify the mechanisms that are crucial to Arctic climate change is to use existing data that exhibit interannual-to-decadal variability in the sea ice and ocean interior due to atmospheric forcing. Since around 1960s, valuable geochemical data of the ocean interior, together with atmospheric and sea ice data, have been analyzed and examined in a coupled ice–ocean model with an idealized configuration of the Arctic Basin. This is fundamentally driven by negative salt flux, in addition to atmospheric circulation and cooling. This strategy has a clear advantage over more sophisticated models with higher resolution that require extensive data collections for veriifcation. Around 1990, the dominant atmospheric mode shifted from the Northern Annular Mode (NAM) to the Arctic Dipole Mode (ADM). The variability of sea ice cover was explained by these two modes sequentially and reproduced in the model. In particular, the geochemical ifelds indicated a movement of the Transpolar Drift Stream due to the NAM and an oscillation of the Paciifc water between the Atlantic and Paciifc sides due to the ADM. Both these features were reproduced reasonably well by the oceanic tracers in the model, including the time lags of about one third of the oscillation periods. Thus, this strategy can suggest methods and locations for monitoring oceanographic responses to Arctic climate change.

  20. Natural products and altered derivatives as tracers for biomass combustion in aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States); Radzi bin Abas, M. [Univ. of Malaya, Kuala Lumpur (Malaysia); Cass, G.R. [California Institute of Technology, Pasadena, CA (United States)] [and others

    1995-12-01

    Biomass combustion is an important primary source of carbonaceous particles in the global atmosphere. Various molecular markers have been proposed for this process but additional specific tracers are needed. The injection of natural product organic compounds into smoke occurs primarily by direct volatilization/steam stripping and by pyrolysis. Although the composition of organic matter in smoke particles is highly variable, the molecular structures of the tracers are generally source specific. Homologous compounds and biomarkers present in smoke are derived directly from plant wax, gum and resin by volatilization and secondarily from pyrolysis of biopolymers (e.g., lignin, cutin, suberin), wax, gum and resin. The component complexity is illustrated with examples from controlled bums of temperate and tropical biomass fuels. Conifer smoke contains characteristic tracers from diterpenoids as well as phenolics and other oxygenated species. These are recognizable in urban airsheds. The major organic components of smoke from tropical biomass are straight-chain, aliphatic and oxygenated compounds and triterpenoids. Several compounds are potential key indicators for combustion of such biomass. The precursor to product approach of organic geochemistry can be applied successfully to provide molecular tracers for studying smoke plume chemistry and dispersion.

  1. Estimation of longitudinal and transverse dispersivities in the Twin Lake natural gradient tracer tests

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Seiji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Moltyaner, G.L.

    1998-06-01

    The field scale tracer tests were carried out with a non-reactive tracer of {sup 131}I at Twin Lake on the Chalk River Laboratory (CRL) site in Atomic Energy of Canada Limited (AECL). The natural gradient dispersion test such as the Twin Lake tracer test is very few and useful for evaluating mass transport parameters and testing groundwater flow and transport models. In this report, mass transport parameters, velocity, longitudinal and transverse dispersivities, were estimated from the Twin Lake 40 m tracer tests. This estimation was performed to provide dispersion data for 3-D transport modelling in the Lake 233 site scale (600 m in east-west direction and 1400 m in north-south direction). Two different methods were applied to the measured breakthrough curves of {sup 131}I in order to evaluate velocity and longitudinal dispersivity. The first method is the fitting procedure of the 1-D advection-dispersion solution, and the second one is the temporal moments analysis. The effect of applying these methods to field data on transport parameters was discussed in this study. The vertical profiles of {sup 131}I were used in the estimation of transverse dispersivity by fitting the 3-D advection-dispersion solution. This report refereed to the effect of variable velocity on the estimated dispersivities. The correlation between magnitude of both dispersivities and the travel distance up to 40 m was also investigated. (author)

  2. Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

    Energy Technology Data Exchange (ETDEWEB)

    Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

    2015-09-01

    This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

  3. Multiple injected and natural conservative tracers quantify mixing in a stream confluence affected by acid mine drainage near Silverton, Colorado

    Science.gov (United States)

    Schemel, L.E.; Cox, M.H.; Runkel, R.L.; Kimball, B.A.

    2006-01-01

    The acidic discharge from Cement Creek, containing elevated concentrations of dissolved metals and sulphate, mixed with the circumneutral-pH Animas River over a several hundred metre reach (mixing zone) near Silverton, CO, during this study. Differences in concentrations of Ca, Mg, Si, Sr, and SO42- between the creek and the river were sufficiently large for these analytes to be used as natural tracers in the mixing zone. In addition, a sodium chloride (NaCl) tracer was injected into Cement Creek, which provided a Cl- 'reference' tracer in the mixing zone. Conservative transport of the dissolved metals and sulphate through the mixing zone was verified by mass balances and by linear mixing plots relative to the injected reference tracer. At each of seven sites in the mixing zone, five samples were collected at evenly spaced increments of the observed across-channel gradients, as determined by specific conductance. This created sets of samples that adequately covered the ranges of mixtures (mixing ratios, in terms of the fraction of Animas River water, %AR). Concentrations measured in each mixing zone sample and in the upstream Animas River and Cement Creek were used to compute %AR for the reference and natural tracers. Values of %AR from natural tracers generally showed good agreement with values from the reference tracer, but variability in discharge and end-member concentrations and analytical errors contributed to unexpected outlier values for both injected and natural tracers. The median value (MV) %AR (calculated from all of the tracers) reduced scatter in the mixing plots for the dissolved metals, indicating that the MV estimate reduced the effects of various potential errors that could affect any tracer.

  4. Multiple injected and natural conservative tracers quantify mixing in a stream confluence affected by acid mine drainage near Silverton, Colorado

    Science.gov (United States)

    Schemel, Laurence E.; Cox, Marisa H.; Runkel, Robert L.; Kimball, Briant A.

    2006-08-01

    The acidic discharge from Cement Creek, containing elevated concentrations of dissolved metals and sulphate, mixed with the circumneutral-pH Animas River over a several hundred metre reach (mixing zone) near Silverton, CO, during this study. Differences in concentrations of Ca, Mg, Si, Sr, and SO42- between the creek and the river were sufficiently large for these analytes to be used as natural tracers in the mixing zone. In addition, a sodium chloride (NaCl) tracer was injected into Cement Creek, which provided a Cl- reference tracer in the mixing zone. Conservative transport of the dissolved metals and sulphate through the mixing zone was verified by mass balances and by linear mixing plots relative to the injected reference tracer. At each of seven sites in the mixing zone, five samples were collected at evenly spaced increments of the observed across-channel gradients, as determined by specific conductance. This created sets of samples that adequately covered the ranges of mixtures (mixing ratios, in terms of the fraction of Animas River water, %AR). Concentratis measured in each mixing zone sample and in the upstream Animas River and Cement Creek were used to compute %AR for the reference and natural tracers. Values of %AR from natural tracers generally showed good agreement with values from the reference tracer, but variability in discharge and end-member concentrations and analytical errors contributed to unexpected outlier values for both injected and natural tracers. The median value (MV) %AR (calculated from all of the tracers) reduced scatter in the mixing plots for the dissolved metals, indicating that the MV estimate reduced the effects of various potential errors that could affect any tracer.

  5. Isotopic and geochemical tracers in the evaluation of groundwater residence time and salinization problems at Santiago Island, Cape Verde

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, Paula M.; Nunes, Dina [Quimica Analitica e Ambiental, IST/ITN, Universidade Tecnica de Lisboa, Estrada Nacional no. 10, 2686-953 Sacavem (Portugal); Marques, Jose M. [Centro de Petrologia e Geoquimica. Instituto Superior Tecnico, UTL, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Monteiro Santos, Fernando A. [Universidade de Lisboa-IDL, 1749-016 Lisboa (Portugal); Goncalves, Rui [Inst. Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Pina, Antonio; Mota Gomes, Antonio [Instituto Superior de Educacao, Praia, Santiago (Cape Verde)

    2013-07-01

    Stable isotopes (δ{sup 18}O, δ{sup 2}H) and tritium ({sup 3}H), together with geochemistry and geophysical data, were used for evaluating groundwater recharge sources, flow paths, and residence times in a watershed on Santiago Island, Cape Verde, West Africa. Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. Low tritium concentrations at seven sampling sites indicate groundwater residence times greater than 50 years. Higher tritium values at other locations suggest more recent recharge. Young ages indicate local recharge and potential groundwater vulnerability to surface contamination and/or salt-water intrusion. Geochemical results indicate that water-rock interaction mechanisms are the major processes responsible for the groundwater quality (mainly calcium-bicarbonate type), reflecting the lithological composition of subsurface soil. (authors)

  6. Natural geochemical risk in the Pollino Massif: a case-study of chromium

    OpenAIRE

    Priscilla Boccia; Salvatore Margiotta

    2015-01-01

    The geochemical risk linked to heavy metal contamination of soils and waters, commonly associated with anthropogenic causes, may, however, be linked to the presence of rocks and soils that naturally contain these metals. Chromium and nickel are particularly abundant in the ultramafic rocks and ophiolitic and in some crystalline rocks, as well as in soils resulting from these pedogenetic processes (Kierczak et al., 2007). The phenomenon of alteration in charge of such rocks can also determine ...

  7. The possible existence of Hs in nature from a geochemical point of view

    CERN Document Server

    Ivanov, A V

    2006-01-01

    A hypothesis of the existence of a long-lived isotope 271Hs in natural molybdenites and osmirides is considered from a geochemical point of view. It is shown that the presence of Hs in these minerals can be explained only by making an additional ad hoc assumption on the existence of an isobaric pair of 271Bh-271Hs. This assumption could be tested by mass-spectrometric measurements of U, Pb, Kr, Xe, and Zr isotopic shifts.

  8. Field studies of streamflow generation using natural and injected tracers on Bickford and Walker Branch Watersheds

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, D.; Hemond, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Civil Engineering; Mulholland, P. [Oak Ridge National Lab., TN (United States)

    1992-05-01

    Field studies of streamflow generation were undertaken on two forested watersheds, the West Road subcatchment of Bickford Watershed in central Massachusetts and the West Fork of Walker Branch Watershed in eastern Tennessee. A major component of the research was development of a two-stage methodology for the use of naturally-occurring {sup 222}Rn as a tracer. The first of the two stages was solving a mass-balance equation for {sup 222}Rn around a stream reach of interest in order to calculate Rn{sub q}, the {sup 222}Rn content of the lateral inflow to the reach; a conservative tracer (chloride) and a volatile tracer (propane) were injected into the study stream to account for lateral inflow to, and volatilization from, the study reach. The second stage involved quantitative comparison of Rn{sub q} to the measured {sup 222}Rn concentrations of different subsurface waters in order to assess how important these waters were in contributing lateral inflow to the stream reach.

  9. Use of a time-domain electromagnetic method with geochemical tracers to explore the salinity anomalies in a small coastal aquifer in north-eastern Tunisia

    Science.gov (United States)

    Chekirbane, Anis; Tsujimura, Maki; Kawachi, Atsushi; Lachaal, Fethi; Isoda, Hiroko; Tarhouni, Jamila

    2014-12-01

    The study area is a small coastal plain in north-eastern Tunisia. It is drained by an ephemeral stream network and is subject to several pollutant discharges such as oilfield brine coming from a neighboring oil company and wastewater from Somâa city, located in the upstream of the plain. Furthermore, a hydraulic head near the coastal part of the aquifer is below sea level, suggesting that seawater intrusion may occur. A time-domain electromagnetic (TDEM) survey, based on 28 soundings, was conducted in Wadi Al Ayn and Daroufa plains to delineate the saline groundwater. Based on longitudinal and transversal resistivity two-dimensional pseudosections calibrated with boring data, the extent of saline water was identified. Geochemical tracers were combined with the resistivity dataset to differentiate the origin of groundwater salinization. In the upstream part of the plain, the infiltration of oilfield brine through the sandy bed of Wadi Al Ayn seems to have a considerable effect on groundwater salinization. However, in the coastal part of the aquifer, groundwater salinization is due to seawater intrusion and the saltwater is reaching an inland extent around 1.3 km from the shoreline. The contribution ratios of saline water bodies derived from the inverted chloride data vary for the oilfield brine from 1 to 13 % and for the seawater from 2 to 21 %.

  10. A cubic matrix-fracture geometry model for radial tracer flow in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Jetzabeth Ramirez-Sabag; Fernando Samaniego V.

    1992-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs, with cubic blocks matrix-fracture geometry. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile where dispersion and convection take place and a stagnant where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared under proper simplified conditions to those previously presented in the literature. The coupled matrix to fracture solution in the Laplace space is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., naturally fractured nearly homogeneous) was carried out. The influence of the three of the main dimensionless parameters that enter into the solution was carefully investigated. A comparison of results for three different naturally fractured systems, vertical fractures (linear flow), horizontal fractures (radial flow) and the cubic geometry model of this study, is presented.

  11. Numerical simulation of a natural gradient tracer experiment for the natural attenuation study: flow and physical transport.

    Science.gov (United States)

    Julian, H E; Boggs, J M; Zheng, C; Feehley, C E

    2001-01-01

    Results are presented for numerical simulations of ground water flow and physical transport associated with a natural gradient tracer experiment conducted within a heterogeneous alluvial aquifer of the Natural Attenuation Study (NATS) site near Columbus, Mississippi. A principal goal of NATS is to evaluate biogeochemical models that predict the rate and extent of natural biodegradation under field conditions. This paper describes the initial phase in the model evaluation process, i.e., calibration of flow and physical transport models that simulate conservative bromide tracer plume evolution during NATS. An initial large-scale flow model (LSM) is developed encompassing the experimental site and surrounding region. This model is subsequently scaled down in telescopic fashion to an intermediate-scale ground water flow model (ISM) covering the tracer-monitoring network, followed by a small-scale transport model (SSM) focused on the small region of hydrocarbon plume migration observed during NATS. The LSM uses inferred depositional features of the site in conjunction with hydraulic conductivity (K) data from aquifer tests and borehole flowmeter tests to establish large-scale K and flow field trends in and around the experimental site. The subsequent ISM incorporates specified flux boundary conditions and large-scale K trends obtained from the calibrated LSM, while preserving small-scale K structure based on some 4000 flowmeter data for solute transport modeling. The configuration of the ISM-predicted potentiometric surface approximates that of the observed surface within a root mean squared error of 0.15 m. The SSM is based on the dual-domain mass-transfer approach. Despite the well-recognized difficulties in modeling solute transport in extremely heterogeneous media as found at the NATS site, the dual-domain model adequately reproduced the observed bromide concentration distributions. Differences in observed and predicted bromide concentration distributions are

  12. Geochemical properties and nuclear chemical characteristics of Oklo natural fission reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Hiroshi [Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Science

    1997-07-01

    There are six uranium deposits in the Gabonese Republic in the cnetral Africa. `Fission reactor zone`, the fission chain reactions generated about 200 billion years ago, was existed in a part of them. CEA begun geochemical researches of Oklo deposits etc. in 1991. The geochemical and nuclear chemical properties of Oklo were reviewed from the results of researches. Oklo deposits is consisted of main five sedimentary faces such as sandstone (FA), Black Shale formation (FB), mudstone (FC), tuff (FD) and volcaniclastic sandstone (FE) from the bottom on the base rock of granite in the Precambrian era. Uranium is enriched in the upper part of FA layer and the under part of FB layer. {sup 235}U/{sup 238}U, U content, fission proportion, duration time, neutron fluence, temperature, restitution factor of {sup 235}U and epithermal index ({gamma}) were investigated and compared. The geochemical properties of Oklo are as followed: large enrich of uranium, the abundance ratio of {sup 235}U as same as that of enriched uranium, interaction of natural water and small rear earth elements. These factors made casually Oklo fission reactor. (S.Y.)

  13. An Investigation of Coastal Groundwater Discharge and Associated Nutrient Inputs Using Electrical Resistivity, Temperature, and Geochemical Tracer in Pescadero Lagoon, California

    Science.gov (United States)

    Volpi, C. M.; Swarzenski, P. W.; McPhee-Shaw, E. E.; Aiello, I. W.

    2014-12-01

    Pescadero Lagoon is a complex lagoon system located on the central California coast in San Mateo County. Over the last decade, external stressors such as degraded water quality, restricted circulation, heightened groundwater withdrawals, changes in the fluvial geomorphology that affect surface water runoff, and widespread agriculture in the watershed have impacted the lagoon. The lagoon system is bounded on the marine side by an ephemeral sand berm that is seasonally closed and so hinders open exchange with the ocean. This berm and the Mediterranean-type climate play an important role in the lagoon's circulation and water quality. The most high-profile and deleterious effect of reduced ocean-lagoon exchange and restricted water circulation is the occurrence of bottom-water low oxygen events that can trigger seasonal fish kills. This project employed a suite of geophysical and geochemical techniques to better understand the role of groundwater on lagoon water and constituent balances. The main objective of this research was to quantify groundwater seepage rates into Pescadero Lagoon across broad spatial and temporal scales using electrical resistivity, temperature, and Radon-222 (222Rn) as tracers of groundwater movement. Resulting seepage rate estimates were then used to derive associated nutrient flux estimates, which can be compared to atmospheric and riverine nutrient load estimates to yield more comprehensive nutrient budgets. The groundwater seepage into the lagoon for the time period of March 2013 to February 2014 was relatively low and did not exceed 0.2 m/day. The timing of the sand berm closure, lack of hydrologic connectivity, and lack of freshwater input proved to be crucial limiting factors in the overall health of the ecosystem.

  14. Strömungs- und Tracer-Transportmodellierung am Natural Attenuation-Standort Zeitz

    Science.gov (United States)

    Gödeke, Stefan; Weiß, Holger; Geistlinger, Helmut; Fischer, Anko; Richnow, Hans Herrmann; Schirmer, Mario

    Kurzfassung Numerische Modelle spielen bei der Bewertung von Natural-Attenuation-Prozessen an Feldstandorten eine bedeutende Rolle. Daher ist es wichtig diese mit Felddaten zu überprüfen und gegebenenfalls erneut zu kalibrieren. Die Modellierung des Transports eines konservativen Tracers auf der Grundlage von Felddaten ergab eine zuverlässigere Abschätzung der Kf-Werte des numerischen Strömungsmodells für den Standort, als es mit anderen Methoden (z. B. Analyse der Siebwerte) möglich war. Die Kf-Werte berechnet aus Siebanalysen führten zu einer deutlichen Unterschätzung der Tracerausbreitungsgeschwindigkeit. Zwischen beobachteten und berechneten Durchbruchskurven wurde eine gute Übereinstimmung erzielt, sodass das Modell für die Planung weiterer Feldexperimente und als Grundlage für eine reaktive Transportmodellierung genutzt werden kann. Die hydraulischen Leitfähigkeiten im Untersuchungsgebiet ändern sich in vertikaler und horizontaler Richtung im Bereich weniger Dezimeter z. T. stark, was von dem numerischen Modell nur begrenzt wiedergegeben werden kann. Für die Modellierung der Tracerausbreitung ist die Kenntnis der Kf-Wert-Verteilung im Bereich des Infiltrationsbrunnens besonders wichtig, weil sie die Struktur der Tracerfahne im Abstrom wesentlich beeinflusst. Die Wahl des numerischen Verfahrens für die Lösung der Transportgleichung hatte bei der Kalibrierung des Strömungsmodells einen großen Einfluss. Während mit dem in MT3DMS vorhandenen TVD (〝Total Variation Diminishing``)-Algorithmus eine akzeptable Lösung gefunden wurde, zeigten sich bei der Verwendung des MOC (〝Method of Characteristics``)-Verfahrens signifikante Fehler in der Massenbilanz. Reliable numerical models are of primary importance for the evaluation of Natural-Attenuation processes at field sites. Modelling the flow and transport of a conservative tracer, a more realistic distribution of the hydraulic conductivity values for the numerical model was achieved and a good

  15. Natural geochemical analogues of the near field of high-level nuclear waste repositories

    Energy Technology Data Exchange (ETDEWEB)

    Apps, J.A. [Lawrence Berkeley Lab., CA (United States)

    1995-09-01

    United States practice has been to design high-level nuclear waste (HLW) geological repositories with waste densities sufficiently high that repository temperatures surrounding the waste will exceed 100{degrees}C and could reach 250{degrees}C. Basalt and devitrified vitroclastic tuff are among the host rocks considered for waste emplacement. Near-field repository thermal behavior and chemical alteration in such rocks is expected to be similar to that observed in many geothermal systems. Therefore, the predictive modeling required for performance assessment studies of the near field could be validated and calibrated using geothermal systems as natural analogues. Examples are given which demonstrate the need for refinement of the thermodynamic databases used in geochemical modeling of near-field natural analogues and the extent to which present models can predict conditions in geothermal fields.

  16. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.

    Science.gov (United States)

    Ma, Long; Wu, Jinglu; Abuduwaili, Jilili; Liu, Wen

    2016-01-01

    Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.

  17. METHYL MERCURY PRODUCTION IN NATURAL-COLLECTED SEDIMENT WITH DIFFERENT GEOCHEMICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    Markus T. Lasut

    2010-06-01

    Full Text Available Production of methyl mercury (MeHg has been shown in laboratory experiments using mercuric chloride (HgCl2 compound released into natural-collected sediments with different geochemical conditions. While the HgCl2 concentration was 30 µl of 113 ppm of HgCl2, the geochemical conditions [pH, salinity, total organic content (TOC, sulfur] of sampled sediments were A: 8.20, 0.00 ppt, 1.97%, and 0.92 ppt, respectively; B: 7.90, 2.00 ppt, 4.69%, and 1.98 ppt, respectively; and C: 8.20, 24.00 ppt, 1.32 %, and 90.90 ppt, respectively. A control was set with no HgCl2. Samples and control were incubated in room temperature of 27 ± 1 °C. Observations were done along 9 days with interval of 3 days. While total Hg was measured using mercury analyzer with Cold Vapor-Atomic Absorbtion Spectrophometer (CV-AAS system, MeHg was measured by using a gas chromatograph with ECD detector after extracted by dithizone-sodium sulfide extraction method. The result shows that MeHg was found in both treatment and control experiments. The concentrations of the MeHg varied according to the geochemical condition of the sampled sediments. Peak production of MeHg occurred on the third day; however, the production was not significantly affected by the incubation time. Optimum production was found inversely related to the pH, in which highest and lowest the pH formed an ineffectively methylated mercury species. The TOC was significantly correlated to the optimum production. Salinity and sulfate contents were found not correlated to the optimum of MeHg production.   Keywords: Methyl mercury; methylation process; sediment; biogeochemistry

  18. Generation of ethylene tracer by noncatalytic pyrolysis of natural gas at elevated pressure

    Science.gov (United States)

    Lu, Y.; Chen, S.; Rostam-Abadi, M.; Ruch, R.; Coleman, D.; Benson, L.J.

    2005-01-01

    There is a critical need within the pipeline gas industry for an inexpensive and reliable technology to generate an identification tag or tracer that can be added to pipeline gas to identify gas that may escape and improve the deliverability and management of gas in underground storage fields. Ethylene is an ideal tracer, because it does not exist naturally in the pipeline gas, and because its physical properties are similar to the pipeline gas components. A pyrolysis process, known as the Tragen process, has been developed to continuously convert the ???2%-4% ethane component present in pipeline gas into ethylene at common pipeline pressures of 800 psi. In our studies of the Tragen process, pyrolysis without steam addition achieved a maximum ethylene yield of 28%-35% at a temperature range of 700-775 ??C, corresponding to an ethylene concentration of 4600-5800 ppm in the product gas. Coke deposition was determined to occur at a significant rate in the pyrolysis reactor without steam addition. The ?? 13C isotopic analysis of gas components showed a ?? 13C value of ethylene similar to ethane in the pipeline gas, indicating that most of the ethylene was generated from decomposition of the ethane in the raw gas. However, ?? 13C isotopic analysis of the deposited coke showed that coke was primarily produced from methane, rather than from ethane or other heavier hydrocarbons. No coke deposition was observed with the addition of steam at concentrations of > 20% by volume. The dilution with steam also improved the ethylene yield. ?? 2005 American Chemical Society.

  19. Methodology Measuring Rare Earth Elements in High TDS Reservoir Brines Application as Natural Tracers in CCUS Studies

    Science.gov (United States)

    Smith, W.; Mcling, T. L.; Smith, R. W.; Neupane, H.

    2013-12-01

    In recent years rare earth elements (REE) have been demonstrated to be useful natural tracers for geochemical processes in aqueous environments. The application of REE's to carbon dioxide utilization and storage (CCUS) could provide researchers with a sensitive, inexpensive tool for tracking the movement of CO2 and displaced formation brines. By definition, geologic reservoirs that have been deemed suitable for carbon capture and storage contain formation brine with total dissolved solids (TDS) greater than 10,000 ppm and often these formation brines exceed 75,000 ppm TDS. This high TDS water makes it very difficult to measure REE, which typically occur at part per trillion concentrations. Critical to the use of REE for CCUS studies is the development of a procedure, which allows for the pre-concentration of REE's across a wide range of water quality. Additionally, due to the large number of samples that will need analysis, any developed procedure must be inexpensive, reproducible, and quick to implement. As part of the Big Sky Carbon Sequestration Project the INL's Center for Advance Energy Studies is developing REE pre-concentration procedures based on methods reported in the literature. While there are many REE pre-concentration procedures in the literature, our tests have shown these methods have difficulty at TDS greater than seawater (roughly 35,000 ppm TDS). Therefore, the ability to quantitatively measure REE's in formation brines with very high TDS has required the modification of an already developed procedure. After careful consideration and testing we selected methods modified after those described by Kingston et al., 1978 and Strachan et al., 1989 utilizing chelating media for very high TDS waters and ion-exchange media as detailed by Crock et al., 1984; Robinson et al., 1985; and Stetzenbach et al., 1994 for low TDS (<10,000 ppm TDS) waters. These modified procedures have been successfully tested in our laboratory and have proven effective in greatly

  20. Use of Natural and Applied Tracers to Guide Targeted Remediation Efforts in an Acid Mine Drainage System, Colorado Rockies, USA

    Directory of Open Access Journals (Sweden)

    Rory Cowie

    2014-03-01

    Full Text Available Stream water quality in areas of the western United States continues to be degraded by acid mine drainage (AMD, a legacy of hard-rock mining. The Rico-Argentine Mine in southwestern Colorado consists of complex multiple-level mine workings connected to a drainage tunnel discharging AMD to passive treatment ponds that discharge to the Dolores River. The mine workings are excavated into the hillslope on either side of a tributary stream with workings passing directly under the stream channel. There is a need to define hydrologic connections between surface water, groundwater, and mine workings to understand the source of both water and contaminants in the drainage tunnel discharge. Source identification will allow targeted remediation strategies to be developed. To identify hydrologic connections we employed a combination of natural and applied tracers including isotopes, ionic tracers, and fluorescent dyes. Stable water isotopes (δ18O/δD show a well-mixed hydrological system, while tritium levels in mine waters indicate a fast flow-through system with mean residence times of years not decades or longer. Addition of multiple independent tracers indicated that water is traveling through mine workings with minimal obstructions. The results from a simultaneous salt and dye tracer application demonstrated that both tracer types can be successfully used in acidic mine water conditions.

  1. Analysis of the migration characteristics of tracers in a heterogeneous flow field through a natural fracture of a domestic granite

    Energy Technology Data Exchange (ETDEWEB)

    Kum, Y. S.; Park, J. K.; Han, P. S. [KAERI, Taejon (Korea, Republic of)

    2001-05-01

    Tracers migration experiment was performed in a natural fracture of a domestic granite. The scale of rock fracture was 100x60x40(cm). In order to observe the migration characteristics, two kinds of nonsorbing tracers were used; as high molecular organic dyes, Eosine, and NaLS, and as anions, Bromide and Chloride. Tracers was injected in a borehole as a band funtion and collected at the opposite borehole. A variable aperture channel model with particle tracking method was used to characterize the aperture width of the fracture and to simulate solute transport. The heterogeneous flow field was modeled by a variable aperture channel model after characterizing aperture distribution by hydraulic tests through boreholes. The particle tracking method applied effectively in simulating tracers transport through a heterogeneous flow field in the rock fracture. Simulated results show that tracers do not migrate through the shortest straight line between inlet and outlet, but migrate through the paths having lowest flow resistance. that is channeling flow.

  2. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122626 Li Dongfeng ( Liaoning Institute of Mineral Resources Exploration,Shenyang 110032,China ) Application of Comprehensive Geophysical-Geochemical Method in Toudao-yingzi Gold Field ( Journal of Liaoning Technical University ( Natural Sciences ), ISSN1008-0562,CN21-1379 / N,30 ( 6 ), 2011,p.849-852,1illus.,2tables,10refs. ) Key words:gold ores,geophysical exploration,geochemical exploration,Liaoning Province

  3. Radon as a natural tracer for gas transport within uranium waste rock piles.

    Science.gov (United States)

    Silva, N C; Chagas, E G L; Abreu, C B; Dias, D C S; Lopez, D; Guerreiro, E T Z; Alberti, H L C; Braz, M L; Branco, O; Fleming, P

    2014-07-01

    Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Indústrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m(-3) with mean concentration of 320.7±263.3 kBq m(-3).

  4. Fluorescent particle tracers in surface hydrology: a proof of concept in a semi-natural hillslope

    Directory of Open Access Journals (Sweden)

    F. Tauro

    2012-08-01

    Full Text Available In this paper, a proof of concept experiment is conducted to assess the feasibility of tracing overland flow on an experimental hillslope plot via a novel fluorescent particle tracer. Experiments are performed by using beads of diameters ranging from 75 to 1180 μm. Particles are sensed through an experimental apparatus comprising a light source and a video acquisition unit. Runoff on the experimental plot is artificially simulated by using a custom-built rainfall system. Particle transits are detected through supervised methodologies requiring the presence of operators and unsupervised procedures based on image analysis techniques. Average flow velocity estimations are executed based on travel time measurements of the particles as they are dragged by the overland flow on the hillslope. Velocities are compared to flow measurements obtained using rhodamine dye. Experimental findings demonstrate the potential of the methodology for understanding overland flow dynamics in complex natural settings. In addition, insights on the optimization of particle size are presented based on the visibility of the beads and their accuracy in flow tracing.

  5. SPATIAL VARIATION OF Zn GEOCHEMICAL FRACTIONS IN THE SURFACE SEDIMENTS OF THE STRAITS OF MALACCA: NATURAL OR ANTHROPOGENIC?

    Institute of Scientific and Technical Information of China (English)

    Chee Kong Yap; Ahmad Ismail; Soon Guan Tan

    2005-01-01

    Total concentrations of Zn in the sediments of the offshore and intertidal areas of the west coast of Peninsular Malaysia were recently reported in the literaturs. However, total concentrations of metals in the sediment samples do not reflect the portion or carrier phase which is attributable to anthropogenic activities and those of natural origins.In this work, geochemical fraction of Zn in the sediments of the same areas was studied and the potential use of CV as an indicator of Zn pollution was determined. The geochemical study by using sequential extraction technique revealed tions, respectively, in the sediments while most of the total zinc concentrations (offshore: 70%; intertidal: 52%)found in the sediments could be mostly due to natural origins (nonresistant fraction). Thus, the Zn levels in the Straits of Malacca should not pose a risk to the liying organisms. Based on Spearman's correlation coefficients, the source of Zn contamination in the Straits of Malacca was mainly contributed by the intertidal coastal area rather than offshore area. The present study also indicated the coefficient of variation can be used as a potential indicator of total summation of geochemical Zn concentrations in the coastal sediment but of different geochemical of Zn needs further validation.

  6. 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

  7. Geochemical tracing of As pollution in the Orbiel Valley (southern France): 87Sr/86Sr as a tracer of the anthropogenic arsenic in surface and groundwater.

    Science.gov (United States)

    Khaska, Mahmoud; Le Gal La Salle, Corinnne; Lancelot, Joël; Verdoux, Patrick; Boutin, René

    2014-05-01

    The environmental impacts of arsenic mining activities and their effects on ecosystem and human health are observed in many stream waters and groundwater. The aim of this study is to identify the origin of As content in a mining environment using Sr isotopes. At the Salsigne gold mine, before the closure in 2004, high arsenic content has been observed in surface water and groundwater in the Orbiel valley. At the site, immobilization of As, in As rich leachate, is carried out by adding CaO. High contrast in 87Sr/86Sr between Arsenic rich minerals associated with Variscan metamorphic rocks (0.714888-0.718835), together with rich As waste water (0.713463-715477), and the CaO (0.707593) allows as to trace the origin of anthropogenic As. In 2012, Orbiel stream waters were sampled monthly upstream and downstream from the ancient ore processing site and once after an important rainy event (117mm). The upstream valley samples showed low and relatively constant As content with natural regional background of 3.6 and 5.6 μg/L. The rainy event induced only a slight increase in the As content up to 6.3 μg/L. High 87Sr/86Sr ratios suggested an influence of radiogenic Sr issued from the Variscan metamorphic basement. Downstream from the area, the As content was at least10 time as high. In the wet season, stream water As content clearly increased to 13.9-24 μg/L, reaching 120.5 μg/L during the rainy event. Associated 87Sr/86Sr ratio showed to be less radiogenic (0.712276-0.714002). The anti correlation observed between As and 87Sr/86Sr suggest that As issued from a natural origin is characterised by a high 87Sr/86Sr compared to As derived from the CaO treatement used on site and characterized by a low 87Sr/86Sr ratio. During the dry season, increase in As content was observed reaching 110 μg/L. These highlights the contribution of alluvial groundwater to base flow, probably associated with As reach leachate from the site. Contribution from the alluvial aquifer is confirmed by

  8. A thalium-doped sodium iodide well counter for radioactive tracer applications with naturally-abundant 40K

    Science.gov (United States)

    Parker, Andrew J.; Boxall, Colin; Joyce, Malcolm J.; Schotanus, Paul

    2013-09-01

    The use of a thallium-doped sodium-iodide well-type scintillation detector for the assay of the low-activity radioisotope 40K, in open-source potassium chloride aqueous solutions, is described. The hazards, safety concerns and radiowaste generation associated with using open-source radioactive isotopes can present significant difficulties, the use of hot cells and escalated costs in radioanalytical laboratory research. A solution to this is the use of low-hazard alternatives that mimic the migration and dispersion characteristics of notable fission products (in this case 137Cs). The use of NaI(Tl) as a detection medium for naturally-abundant levels of 40K in a range of media is widespread, but the use of 40K as a radioactive tracer has not been reported. The use of such low-activity sources is often complicated by the ability to detect them efficiently. In this paper a scintillator detector designed to detect the naturally-abundant 40K present in potassium chloride in tracer applications is described. Examples of the use of potassium chloride as a tracer are given in the context of ion exchange and electrochemical migration studies, and comparisons in performance are drawn from literature with hyper pure germanium semiconductor detectors, which are more commonly utilised detectors in high-resolution counting applications.

  9. Sorption and transformation of the reactive tracers resazurin and resorufin in natural river sediments

    Science.gov (United States)

    Lemke, D.; González-Pinzón, R.; Liao, Z.; Wöhling, T.; Osenbrück, K.; Haggerty, R.; Cirpka, O. A.

    2014-08-01

    Resazurin (Raz) and its reaction product resorufin (Rru) have increasingly been used as reactive tracers to quantify metabolic activity and hyporheic exchange in streams. Previous work has indicated that these compounds undergo sorption in stream sediments. We present laboratory experiments on Raz and Rru transport, sorption, and transformation, consisting of 4 column and 72 batch tests using 2 sediments with different physicochemical properties under neutral (pH = 7) and alkaline (pH = 9) conditions. The study aimed at identifying the key processes of reactive transport of Raz and Rru in streambed sediments and the experimental setup best suited for their determination. Data from column experiments were simulated by a travel-time-based model accounting for physical transport, equilibrium and kinetic sorption, and three first-order reactions. We derived the travel-time distributions directly from the breakthrough curve (BTC) of the conservative tracer, fluorescein, rather than from fitting an advective-dispersive transport model, and inferred from those distributions the transfer functions of Raz and Rru, which provided conclusive approximations of the measured BTCs. The most likely reactive transport parameters and their uncertainty were determined by a Markov chain-Monte Carlo approach. Sorption isotherms of both compounds were obtained from batch experiments. We found that kinetic sorption dominates sorption of both Raz and Rru, with characteristic timescales of sorption in the order of 12 to 298 min. Linear sorption models for both Raz and Rru appeared adequate for concentrations that are typically applied in field tracer tests. The proposed two-site sorption model helps to interpret transient tracer tests using the Raz-Rru system.

  10. Natural radium and radon tracers to quantify water exchange and movement in reservoirs

    Science.gov (United States)

    Smith, Christopher G.; Baskaran, Mark

    2011-01-01

    Radon and radium isotopes are routinely used to quantify exchange rates between different hydrologic reservoirs. Since their recognition as oceanic tracers in the 1960s, both radon and radium have been used to examine processes such as air-sea exchange, deep oceanic mixing, benthic inputs, and many others. Recently, the application of radon-222 and the radium-quartet (223,224,226,228Ra) as coastal tracers has seen a revelation with the growing interest in coastal groundwater dynamics. The enrichment of these isotopes in benthic fluids including groundwater makes both radium and radon ideal tracers of coastal benthic processes (e.g. submarine groundwater discharge). In this chapter we review traditional and recent advances in the application of radon and radium isotopes to understand mixing and exchange between various hydrologic reservoirs, specifically: (1) atmosphere and ocean, (2) deep and shallow oceanic water masses, (3) coastal groundwater/benthic pore waters and surface ocean, and (4) aquifer-lakes. While the isotopes themselves and their distribution in the environment provide qualitative information about the exchange processes, it is mixing/exchange and transport models for these isotopes that provide specific quantitative information about these processes. Brief introductions of these models and mixing parameters are provided for both historical and more recent studies.

  11. Sorption and transformation of the reactive tracers resazurin and resorufin in natural river sediments

    Directory of Open Access Journals (Sweden)

    D. Lemke

    2013-10-01

    Full Text Available Resazurin (Raz and its reaction product resorufin (Rru have increasingly been used as reactive tracers to quantify metabolic activity and hyporheic exchange in streams. Previous works have indicated that these compounds undergo sorption in stream sediments. We present a series of laboratory column and batch experiments on Raz and Rru transport, sorption, and transformation within sediments with different physicochemical properties under neutral and alkaline conditions. The data of the column experiments were fitted by a model accounting for physical transport, equilibrium and kinetic sorption, and three first-order reactions. The most likely parameters and their uncertainty were determined by a Markov-Chain Monte Carlo approach. Linear and non-linear sorption isotherms of both compounds were obtained by batch experiments. We found that kinetic sorption dominates sorption of both Raz and Rru, with characteristic timescales of sorption in the order of > 80 min. The linear sorption models for both Raz and Rru appeared adequate for concentrations that are typically applied in field-tracer tests. The supposed two-site sorption model helps interpreting transient tracer tests using the Raz–Rru system.

  12. Geochemical Characteristics and Origin of Natural Gases in the Qaidam Basin, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Sixty-five natural gas samples were collected from 19 oil-gasfields in the Qaidam basin, China. The chemical composition and carbon isotope values of the samples were measured, and the geochemical characteristics and origin of the natural gases were studied. The gases can be divided into biogenic gases, sapropelic oil-type gases, mixed type oil-type gases, coal-type gases and mixed gas. The δ13C1 values of the biogenic gases are very small and the C2+ contents of them are very low, ranging from -68.2‰ to -61.8‰ and 0.06% to 0.20% respectively. They have heavy δD and δ13CCO2, showing a CO2 reduction pathway. They are distributed in the East depression region and derived from the Quaternary source rocks. The sapropelic oil-type gases have small δ13C2 values and high C2+ ranging from -36.6‰ to -28.6‰ and from 33.01% to 47.15% respectively. The mixed type oil-type gases have δ13C2 values and C2+ contents varying from -28.6‰ to -24.8‰ and from 4.81% to 26.06% respectively. Both sapropelic oil-type gases and mixed type oil-type gases are associated with oil-type oils, distributed in the West depression region and derived from the Tertiary saltwater lacustrine sapropelic source rocks and humic source rocks respectively. The δ13C2 values of the coal-type gases are extremely high and the C2+ contents are very low, changing from -23.3‰ to -12.5‰ and from 0.06% to 18.07% respectively. The coal-type gases in the Nanbaxian gasfield and the Lenghu oil-gasfields in the North fault block belt are derived from the Middle Jurassic coal-measures source rocks, whereas those in the West depression region are derived from the Tertiary saltwater lacustrine humic source rocks. Compared with some other basins in China, the natural gases there have obviously heavier δ13C due to the heavier δ13C of different types of kerogens of the Tertiary saltwater lacustrine source rocks in the West depression region of the basin. The mixing of natural gases is common in the West

  13. Discrepant estimates of primary and export production from satellite algorithms, a biogeochemical model, and geochemical tracer measurements in the North Pacific Ocean

    Science.gov (United States)

    Palevsky, Hilary I.; Quay, Paul D.; Nicholson, David P.

    2016-08-01

    Estimates of primary and export production (PP and EP) based on satellite remote sensing algorithms and global biogeochemical models are widely used to provide year-round global coverage not available from direct observations. However, observational data to validate these approaches are limited. We find that no single satellite algorithm or model can reproduce seasonal and annual geochemically determined PP, export efficiency (EP/PP), and EP rates throughout the North Pacific basin, based on comparisons throughout the full annual cycle at time series stations in the subarctic and subtropical gyres and basin-wide regions sampled by container ship transects. The high-latitude regions show large PP discrepancies in winter and spring and strong effects of deep winter mixed layers on annual EP that cannot be accounted for in current satellite-based approaches. These results underscore the need to evaluate satellite- and model-based estimates using multiple productivity parameters measured over broad ocean regions throughout the annual cycle.

  14. Design and analysis of a natural-gradient ground-water tracer test in a freshwater tidal wetland, West Branch Canal Creek, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Olsen, Lisa D.; Tenbus, Frederick J.

    2005-01-01

    A natural-gradient ground-water tracer test was designed and conducted in a tidal freshwater wetland at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The objectives of the test were to characterize solute transport at the site, obtain data to more accurately determine the ground-water velocity in the upper wetland sediments, and to compare a conservative, ionic tracer (bromide) to a volatile tracer (sulfur hexafluoride) to ascertain whether volatilization could be an important process in attenuating volatile organic compounds in the ground water. The tracer test was conducted within the upper peat unit of a layer of wetland sediments that also includes a lower clayey unit; the combined layer overlies an aquifer. The area selected for the test was thought to have an above-average rate of ground-water discharge based on ground-water head distributions and near-surface detections of volatile organic compounds measured in previous studies. Because ground-water velocities in the wetland sediments were expected to be slow compared to the underlying aquifer, the test was designed to be conducted on a small scale. Ninety-seven ?-inch-diameter inverted-screen stainless-steel piezometers were installed in a cylindrical array within approximately 25 cubic feet (2.3 cubic meters) of wetland sediments, in an area with a vertically upward hydraulic gradient. Fluorescein dye was used to qualitatively evaluate the hydrologic integrity of the tracer array before the start of the tracer test, including verifying the absence of hydraulic short-circuiting due to nonnatural vertical conduits potentially created during piezometer installation. Bromide and sulfur hexafluoride tracers (0.139 liter of solution containing 100,000 milligrams per liter of bromide ion and 23.3 milligrams per liter of sulfur hexafluoride) were co-injected and monitored to generate a dataset that could be used to evaluate solute transport in three dimensions. Piezometers were sampled 2 to 15 times

  15. Geochemical processes controlling water salinization in an irrigated basin in Spain: Identification of natural and anthropogenic influence

    Energy Technology Data Exchange (ETDEWEB)

    Merchán, D., E-mail: d.merchan@igme.es [Geological Survey of Spain — IGME, C/Manuel Lasala 44 9B, 50006 Zaragoza (Spain); Auqué, L.F.; Acero, P.; Gimeno, M.J. [University of Zaragoza — Department of Earth Sciences (Geochemical Modelling Group), C/Pedro Cerbuna 12, 50009 Zaragoza (Spain); Causapé, J. [Geological Survey of Spain — IGME, C/Manuel Lasala 44 9B, 50006 Zaragoza (Spain)

    2015-01-01

    Salinization of water bodies represents a significant risk in water systems. The salinization of waters in a small irrigated hydrological basin is studied herein through an integrated hydrogeochemical study including multivariate statistical analyses and geochemical modeling. The study zone has two well differentiated geologic materials: (i) Quaternary sediments of low salinity and high permeability and (ii) Tertiary sediments of high salinity and very low permeability. In this work, soil samples were collected and leaching experiments conducted on them in the laboratory. In addition, water samples were collected from precipitation, irrigation, groundwater, spring and surface waters. The waters show an increase in salinity from precipitation and irrigation water to ground- and, finally, surface water. The enrichment in salinity is related to the dissolution of soluble mineral present mainly in the Tertiary materials. Cation exchange, precipitation of calcite and, probably, incongruent dissolution of dolomite, have been inferred from the hydrochemical data set. Multivariate statistical analysis provided information about the structure of the data, differentiating the group of surface waters from the groundwaters and the salinization from the nitrate pollution processes. The available information was included in geochemical models in which hypothesis of consistency and thermodynamic feasibility were checked. The assessment of the collected information pointed to a natural control on salinization processes in the Lerma Basin with minimal influence of anthropogenic factors. - Highlights: • Salinization in Lerma Basin was controlled by the dissolution of soluble salts. • Water salinization and nitrate pollution were found to be independent processes. • High NO{sub 3}, fresh groundwater evolved to lower NO{sub 3}, higher salinity surface water. • Inverse and direct geochemical modeling confirmed the hypotheses. • Salinization was a natural ongoing process

  16. Constraining Water Fluxes Through the Streambed of a Semi-arid Losing Stream Using Natural Tracers: Heat and Radioisotopes

    Science.gov (United States)

    Andersen, M. S.; Rau, G. C.; McCallum, A. M.; Meredith, K.; Acworth, I.

    2011-12-01

    Natural physical and chemical tracers of flow have different advantages and shortfalls based on their properties and the uncertainty related to variability in their source concentration. Each tracer integrates over a characteristic spatial-temporal scale depending on its decay or production rate and the flow velocity of the system. For instance heat tracing using diurnal temperature fluctuations will, at best, provide information about flow in the upper 1-2 m of the streambed before the signal is dampened below measurement resolution (Constantz et al. 2003). Conversely, radioisotopes used as tracers will integrate over increasing spatio-temporal scales for decreasing decay constants. Radioisotopes with comparatively slow decay rates will be less sensitive for resolving flow conditions on short spatio-temporal scales. Therefore, it is difficult to use these tracers in the streambed of losing systems because the radioactive decay is not discernible against the variability. Consequently, employing a combination of different tracers provides information on different parts of a given flow system. Comparing flow velocities derived from tracers integrating over different scales allows for separating the local hyporheic exchange from the regional groundwater recharge. A field experiment was carried out in a perennial section of the mostly ephemeral Maules Creek in NSW, Australia. Streambed temperature profiles were monitored at three sites along a 400 m stretch of the perennial reach. Streambed temperatures were recorded at 4 depths within one meter below the streambed. Water samples were collected from surface water, streambed and groundwater and analysed for stable water isotopes (18O and 2H) and radioisotopes (222Rn and 3H). The streambed heat profiles provided time series of surface water/groundwater exchange. Using this method it was found that the conditions were losing at all three sites with recharge rates varying between 0 and 0.4 m/d. 222Rn measurements in the

  17. Novel and non-traditional use of stable isotope tracers to study metal bioavailability from natural particles

    Science.gov (United States)

    Croteau, Marie-Noële; Cain, Daniel J.; Fuller, Christopher C.

    2013-01-01

    We devised a novel tracing approach that involves enriching test organisms with a stable metal isotope of low natural abundance prior to characterizing metal bioavailability from natural inorganic particles. In addition to circumventing uncertainties associated with labeling natural particles and distinguishing background metals, the proposed "reverse labeling" technique overcomes many drawbacks inherent to using radioisotope tracers. Specifically, we chronically exposed freshwater snails (Lymnaea stagnalis) to synthetic water spiked with Cu that was 99.4% 65Cu to increase the relative abundance of 65Cu in the snail’s tissues from 32% to >80%. The isotopically enriched snails were then exposed to benthic algae mixed with Cu-bearing Fe–Al particles collected from the Animas River (Colorado), an acid mine drainage impacted river. We used 63Cu to trace Cu uptake from the natural particles and inferred their bioavailability from calculation of Cu assimilation into tissues. Cu assimilation from these particles was 44%, indicating that 44% of the particulate Cu was absorbed by the invertebrate. This demonstrates that inorganic particulate Cu can be bioavailable. The reverse labeling approach shows great potential in various scientific areas such as environmental contamination and nutrition for addressing questions involving uptake of an element that naturally has multiple isotopes.

  18. Chemical parameters as natural tracers in hydrogeology: a case study of Louros karst system, Greece

    Science.gov (United States)

    Katsanou, K.; Lambrakis, N.; D'Alessandro, W.; Siavalas, G.

    2017-03-01

    The Louros Basin hosts one of the most important karst systems of Epirus Prefecture (Greece) and plays a key role in supplying three counties with drinking water. Aiming to investigate the origin of groundwater and its flow patterns, a multi-tracer approach was used to describe and evaluate the hydrogeology of the system. Therefore, 271 surface water and groundwater samples were collected and analyzed for physicochemical parameters, major ions, and trace and rare earth elements, as well as stable isotopes (δ18O and δ2H). These data provided meaningful tracing of the water origin, water-rock interaction processes, and relationships among the aquifers. In particular, the elaboration of the major ions supported by the distribution of rare earth elements indicated that there are three aquifers located at different levels hosted in the Senonian and Pantokrator limestone formations. These aquifers are hydraulically interconnected by a cascade and constitute the Louros karst system which is drained by the homonymous river. Hydrochemical and isotopic data revealed that the Louros karst system is isolated from the adjacent northern Ioannina Basin and it is being recharged by precipitation. Higher groundwater salinity, where present, is mainly associated with increased water-rock interaction due to longer and deeper hydrologic flow, favoring the dissolution of evaporitic, carbonate and phosphate minerals.

  19. Experimental and Numerical Investigation of the Tracer Gas Methodology in the Case of a Naturally Cross-Ventilated Building

    DEFF Research Database (Denmark)

    Nikolopoulos, Nikos; Nikolopoulos, Aristeidis; Larsen, Tine Steen

    2012-01-01

    The paper presents the investigation of a naturally cross – ventilated building using both experimental and numerical methods with the parameters being the free-stream and the incidence angle of the wind to the openings of the building. The experimental methodology calculates the air change rate...... based either on measurements of the inlet velocity profile, the outlet velocity profile or the descending rate of the tracer gas concentration using the decay method. The numerical investigation is based on the solution of the governing Navier-Stokes equations in their full three dimensional expression......, focusing on the time dependent character of the induced flow field. The numerical results are compared with corresponding experimental data for the three aforementioned experimental methodologies in the case of a full scale building inside a wind-tunnel. The numerical investigation reveals that for large...

  20. Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System

    Science.gov (United States)

    Barnard, Patrick L.; Foxgrover, Amy C.; Elias, Edwin P.L.; Erikson, Li H.; Hein, James R.; McGann, Mary; Mizell, Kira; Rosenbauer, Robert J.; Swarzenski, Peter W.; Takesue, Renee K.; Wong, Florence L.; Woodrow, Donald L.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    Over 150 million m3 of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply and recent widespread erosion of adjacent beaches, wetlands, and submarine environments. A unique, multi-faceted provenance study was performed to definitively establish the primary sources, sinks, and transport pathways of beach-sized sand in the region, thereby identifying the activities and processes that directly limit supply to the outer coast. This integrative program is based on comprehensive surficial sediment sampling of the San Francisco Bay Coastal System, including the seabed, Bay floor, area beaches, adjacent rock units, and major drainages. Analyses of sample morphometrics and biological composition (e.g., Foraminifera) were then integrated with a suite of tracers including 87Sr/86Sr and 143Nd/144Nd isotopes, rare earth elements, semi-quantitative X-ray diffraction mineralogy, and heavy minerals, and with process-based numerical modeling, in situ current measurements, and bedform asymmetry to robustly determine the provenance of beach-sized sand in the region.

  1. A pilot study to assess the feasibility of using naturally-occurring radionuclides as mass balance tracers to estimate soil ingestion.

    Science.gov (United States)

    Doyle, J R; White, P A; Blais, J M

    2012-09-01

    The relatively few soil ingestion studies that have been conducted to date to support soil ingestion rate values used for contaminated site human health risk assessments (HHRAs) typically have measured mass balance elemental tracers (e.g., Al, Si, Ba, Ce, Mn, Ti, V, Zr), found in soil to estimate soil ingestion. This pilot study, involving a canine subject fed a known amount of tracer on a daily basis, assessed the use of alternative mass balance tracers, specifically naturally occurring radionuclides of the (238)U and (232)Th decay series, to estimate soil ingestion. A novel method of estimating soil ingestion via difference in isotopic ratios between the two decay series in food and soil was also assessed. The results of the study showed that the mean (214)Pb and (212)Pb activities measured in fecal samples were greater than what was contained in the soil inoculant, suggesting that the tracers were not being significantly absorbed in the GI tract. The mean daily soil ingestion rates, calculated after subtracting the contribution of tracers in the soil inoculant, were 3.9 g d(-1) (standard deviation 3.6 g d(-1)) for the isotope tracers, and 1.9 g(-1) (standard deviation 2.1 g d(-1)) for the 3 most reliable elemental tracers. The differences were not statistically significant and further evaluation of isotopic tracers for soil ingestion studies is warranted. Similarly, soil ingestion estimates calculated using the Isotope Ratio Method were not significantly different than when calculated using (212)Pb; however, the Isotope Ratio Method was observed to positively bias the soil ingestion estimates by approximately 50%. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Geochemical processes controlling water salinization in an irrigated basin in Spain: identification of natural and anthropogenic influence.

    Science.gov (United States)

    Merchán, D; Auqué, L F; Acero, P; Gimeno, M J; Causapé, J

    2015-01-01

    Salinization of water bodies represents a significant risk in water systems. The salinization of waters in a small irrigated hydrological basin is studied herein through an integrated hydrogeochemical study including multivariate statistical analyses and geochemical modeling. The study zone has two well differentiated geologic materials: (i) Quaternary sediments of low salinity and high permeability and (ii) Tertiary sediments of high salinity and very low permeability. In this work, soil samples were collected and leaching experiments conducted on them in the laboratory. In addition, water samples were collected from precipitation, irrigation, groundwater, spring and surface waters. The waters show an increase in salinity from precipitation and irrigation water to ground- and, finally, surface water. The enrichment in salinity is related to the dissolution of soluble mineral present mainly in the Tertiary materials. Cation exchange, precipitation of calcite and, probably, incongruent dissolution of dolomite, have been inferred from the hydrochemical data set. Multivariate statistical analysis provided information about the structure of the data, differentiating the group of surface waters from the groundwaters and the salinization from the nitrate pollution processes. The available information was included in geochemical models in which hypothesis of consistency and thermodynamic feasibility were checked. The assessment of the collected information pointed to a natural control on salinization processes in the Lerma Basin with minimal influence of anthropogenic factors.

  3. Hydrochemistry and boron isotopes as natural tracers in the study of groundwaters from North Chianan Plain, Taiwan.

    Science.gov (United States)

    Lu, Hsueh-Yu

    2014-01-01

    In this paper, hydrochemistry and boron isotopes are successfully applied to elucidate hydrogeological processes by the use of natural tracers. The hydrochemical analysis identifies four end-members in the hydrochemical evolution of groundwater from the North Chianan plain groundwater district. A few groundwater contain extraordinary chlorine concentrations of up to 48,000 mg l(-1). However, the hydrochemistry of groundwater only reveals that high saline water is a dominant factor in groundwater hydrochemistry. It is thought that these groundwater experienced precipitation of carbonates during seawater evaporation that did not involve the precipitation of gypsum. Boron isotopes are very efficient tracers in determining the source of salinisation. The boron isotopes reveal the results of mixing of evaporated seawater and water-sediment interaction. In general, the boron isotope ratio of the groundwater is controlled by a two-end-member mixing system, which is composed of evaporated seawater (isotopically heavy) and fresh surface water (isotopically light). Due to a long lagoonal period in the coastal plain, the groundwaters in the downstream area generally have high Cl/B ratios and relatively heavy boron isotope ratios while those in the upstream area are composed of low Cl/B and light boron isotopes. However, there is not a resolvable mixing trend between the Cl/B ratio and the isotopic composition of boron. It is probably obscured by a highly variable boron isotope ratio in fresh surface water and through fractionation associated with water-rock interaction. Both factors would decrease the boron isotope ratio but one effect cannot be distinguished from the other.

  4. Carbon monoxide as a tracer of gas transport in snow and other natural porous media

    NARCIS (Netherlands)

    Huwald, H.; Selker, J.S.; Tyler, S.W.; Calaf, M.; Van de Giesen, N.C.; Parlange, M.B.

    2012-01-01

    The movement of air in natural porous media is complex and challenging to measure. Yet gas transport has important implications, for instance, for the evolution of the seasonal snow cover and for water vapor transport in soil. A novel in situmulti-sensor measurement system providing high-resolution

  5. The importance of the poikilohydric nature of lichens as natural tracers for delta18O of ambient vapour

    Science.gov (United States)

    Hartard, Britta; Cuntz, Matthias; Lakatos, Michael; Máguas, Cristina

    2010-05-01

    The stable isotope composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in poikilohydric organisms (i.e. lichens and bryophytes), where relative water content equilibrate with the surrounding humidity conditions and that are able to use distinct water sources such as precipitation, dew, fog and also water vapour. Moreover, lichens are ubiquitous organisms, and on a global scale, they are found in nearly all terrestrial ecosystems and also within these ecosystems they inhabit many microhabitats. As poikilohydric. especially green algal lichens are known to photosynthetically reactivate solely upon uptake of atmospheric moisture, even at non-saturated ambient humidity conditions. To understand basic isotope exchange processes on non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrates with the isotopic composition of surrounding water vapour. We found that the thallus water of lichens exposed to high relative humidity shows fast isotopic equilibration with the surrounding vapour regardless of whether the lichen experiences water loss or vapour uptake. The time until isotopic equilibrium is achieved depends on the initial water status as well as on the lichen's specific morphology. It ranged from 5 to 12h in previously dried lichens to approximately 40h in lichens previously rehydrated with liquid water of distinct isotopic composition. Even though markedly slower, isotopic equilibration between leaf water and ambient vapour may also occur in homoiohydric plants exposed to high relative humidity. At low relative humidity, however, the apparent vapour pressure deficit between the evaporative sites and the ambient air and the increased stomatal diffusion resistance generally causes leaf water enrichment. In contrast, poikilohydric lichens lack

  6. A study on the geochemical characteristics of natural gas and gas sources in the Bozhong sag

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Natural gas is composed largely of hydrocarbon gas, especially wet gas in the Bozhong sag. The carbon isotopic composition shows that the gas is of organic origin. The carbon isotopic values of ethane indicate that the natural gas is dominated by mixed gas with minor coal-generated gas and oil-type gas. A gas-source correlation study showed that the source rocks of natural gas are those of the Lower Dongying Formation, the Shahejie Formation and the pre-Tertiary. The natural gas is characterized by multi-source and continuous generation in the study area, indicating that gas exploration potential is good in the Bozhong sag.

  7. Geochemical Signature of Natural Water Recharge in the Jungar Basin and Its Response to Climate.

    Science.gov (United States)

    Zhu, Bingqi; Yu, Jingjie; Rioual, Patrick

    2016-01-01

    This paper analyzed the physico-chemical characteristics of natural waters in a drainage system of the Jungar Basin, northwestern China to identify chemical evolution and recharge mechanisms of natural waters in an arid environment. The waters studied are different in mineralization, but are typically carbonate rivers and alkaline in nature. No Cl-dominated water type occurs, indicating an early stage of water evolution. Regolith and geomorphological parameters controlling ground-surface temperature may play a large role in the geological evolution of the water. Three main morphological and hydrological units are reflected in water physico-chemistry. Climate influences the salinization of natural waters substantially. Direct recharge from seasonal snow and ice-melt water and infiltration of rain to the ground are significant recharge processes for natural waters, but recharge from potential deep groundwater may be less important. The enrichment of ions in lakes has been mainly caused by evaporation rather than through the quality change of the recharged water.

  8. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in

  9. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in th

  10. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in th

  11. Application of natural isotope tracers to geothermal research in the Maechan fault zone (N Thailand)

    Science.gov (United States)

    Yongprawat, Monthon; Kamdee, Kiatipong; Sauter, Martin; Wiegand, Bettina

    2017-04-01

    Previous geothermal research in Thailand has mainly focused on high-potential geothermal systems such as the active Maechan fault zone, which is located in the northern part of the country. Fang and Maechan hot springs have been the primary targets for power generation and agricultural applications (Apollaro et al. 2015). Here we present a comprehensive survey of chemical and isotopic compositions of thermal waters from six hot springs, well water, and cold surface water samples. This study aims to identify sources of the geothermal waters, hydrodynamic processes and the thermal capacity of the hot springs along the Maechan fault zone. Field parameters, major ions, stable isotopes of hydrogen, oxygen, and carbon, as well as radiocarbon and tritium were investigated. The chemical composition of both thermal waters and cold surface waters is dominated by the Na-HCO3 type. δ2HSMOW and δ18OSMOW data of thermal water and cold surface water plot along a local meteoric water line, suggesting local precipitation as the source of thermal water in the area. δ13CPDB values between -4 to -16 ‰ indicate that dissolved carbon in the thermal water samples is mainly from inorganic carbon sources but some mixture with organic carbon may occur. Radiocarbon analyses (10-20 pMC) suggest ages of more than 10,000 years for the formation of the thermal waters. Tritium concentrations range between 0-0.2 TU. Bibliography Apollaro, C., Vespasiano, G., De Rosa, R., Marini, L. Use of Mean Residence Time and Flowrate of Thermal Waters to Evaluate the Volume of Reservoir Water Contributing to the Natural Discharge and the Related Geothermal Reservoir Volume. Application to Northern Thailand Hot Springs." Geothermics 58: 62-74. 2015.

  12. Use of the radon gas as a natural geophysical tracer; Utilizacion del gas radon como un trazador geofisico natural

    Energy Technology Data Exchange (ETDEWEB)

    Pena, P.; Balcazar, M.; Flores R, J.H.; Lopez M, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2006-07-01

    In this work it is denoted the applications of the radon gas like a natural geophysical radiotracer in the different branches of the Earth Sciences (Geology, geophysics and geochemistry). It importance resides in its employment like one additional tool to register the possible occurrence of seismic events by means of radon anomalies that are presented in land movements (volcanic eruptions and presence of geothermal areas), as well as its potential in environmental works whose purpose is the evaluation of the feather of contamination in the underground water and the porous media for spills of hydrocarbons. The measurement techniques to determine the concentration of radon was carried out by means of Solid Detectors of Nuclear tracks, as well as by Liquid scintillation, Clipperton, Honeywell, AlphaGUARD. The towns where these techniques its were applied were: Mexico City, Estado de Mexico (Toluca, ININ), Jalisco (The Spring), Guerrero coast. (Author)

  13. Food Resources of Stream Macronivertebrates Determined by Natural-Abundance stable C and N Isotopes and a 15N Tracer Addition

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, P. J.

    2000-01-01

    Trophic relationships were examined using natural-abundance {sup 13}C and {sup 15}N analyses and a {sup 15}N-tracer addition experiment in Walker Branch, a 1st-order forested stream in eastern Tennessee. In the {sup 15}N-tracer addition experiment, we added {sup 15}NH{sub 4} to stream water over a 6-wk period in early spring, and measured {sup 15}N:{sup 14}N ratios in different taxa and biomass compartments over distance and time. Samples collected from a station upstream from the {sup 15}N addition provided data on natural-abundance {sup 13}C:{sup 12}C and {sup 15}N:{sup 14}N ratios. The natural-abundance {sup 15}N analysis proved to be of limited value in identifying food resources of macroinvertebrates because {sup 15}N values were not greatly different among food resources. In general, the natural-abundance stable isotope approach was most useful for determining whether epilithon or detritus were important food resources for organisms that may use both (e.g., the snail Elimia clavaeformis), and to provide corroborative evidence of food resources of taxa for which the {sup 15}N tracer results were not definitive. The {sup 15}N tracer results showed that the mayflies Stenonema spp. and Baetis spp. assimilated primarily epilithon, although Baetis appeared to assimilate a portion of the epilithon (e.g., algal cells) with more rapid N turnover than the bulk pool sampled. Although Elimia did not reach isotopic equilibrium during the tracer experiment, application of a N-turnover model to the field data suggested that it assimilated a combination of epilithon and detritus. The amphipod Gammarus minus appeared to depend mostly on fine benthic organic matter (FBOM), and the coleopteran Anchytarsus bicolor on epixylon. The caddisfly Diplectrona modesta appeared to assimilate primarily a fast N-turnover portion of the FBOM pool, and Simuliidae a fast N-turnover component of the suspended particulate organic matter pool rather than the bulk pool sampled. Together, the

  14. Naturally occurring arsenic in groundwater and identification of the geochemical sources in the Duero Cenozoic Basin, Spain

    Science.gov (United States)

    Gómez, J. J.; Lillo, J.; Sahún, B.

    2006-09-01

    Arsenic concentrations surpassing potability limit of 10 μg/L in the groundwater supplies of an extensive area in the Duero Cenozoic Basin (central Spain) have been detected and the main sources of arsenic identified. Arsenic in 514 samples of groundwater, having mean values of 40.8 μg/L, is natural in origin. Geochemical analysis of 553 rock samples, assaying arsenic mean values of 23 mg/kg, was performed. Spatial coincidence between the arsenic anomaly in groundwater and the arsenic lithogeochemical distribution recorded in the Middle Miocene clayey organic-rich Zaratan facies illustrates that the rocks of this unit are the main source of arsenic in groundwater. The ferricretes associated to the Late Cretaceous-Middle Miocene siliciclastics also constitute a potential arsenic source. Mineralogical study has identified the presence of arsenic in iron oxides, authigenic pyrite, manganese oxides, inherited titanium-iron oxides, phyllosilicates and organomineral compounds. Arsenic mobilization to groundwater corresponds to arsenic desorption from iron and manganese oxides and from organic matter.

  15. Chemical Tracer Methods: Chapter 7

    Science.gov (United States)

    Healy, Richard W.

    2017-01-01

    Tracers have a wide variety of uses in hydrologic studies: providing quantitative or qualitative estimates of recharge, identifying sources of recharge, providing information on velocities and travel times of water movement, assessing the importance of preferential flow paths, providing information on hydrodynamic dispersion, and providing data for calibration of water flow and solute-transport models (Walker, 1998; Cook and Herczeg, 2000; Scanlon et al., 2002b). Tracers generally are ions, isotopes, or gases that move with water and that can be detected in the atmosphere, in surface waters, and in the subsurface. Heat also is transported by water; therefore, temperatures can be used to trace water movement. This chapter focuses on the use of chemical and isotopic tracers in the subsurface to estimate recharge. Tracer use in surface-water studies to determine groundwater discharge to streams is addressed in Chapter 4; the use of temperature as a tracer is described in Chapter 8.Following the nomenclature of Scanlon et al. (2002b), tracers are grouped into three categories: natural environmental tracers, historical tracers, and applied tracers. Natural environmental tracers are those that are transported to or created within the atmosphere under natural processes; these tracers are carried to the Earth’s surface as wet or dry atmospheric deposition. The most commonly used natural environmental tracer is chloride (Cl) (Allison and Hughes, 1978). Ocean water, through the process of evaporation, is the primary source of atmospheric Cl. Other tracers in this category include chlorine-36 (36Cl) and tritium (3H); these two isotopes are produced naturally in the Earth’s atmosphere; however, there are additional anthropogenic sources of them.

  16. Results of radiometric and geochemical measurement for the natural radioactivity map of Slovenia

    Directory of Open Access Journals (Sweden)

    Mišo Andjelov

    1994-12-01

    Full Text Available In 1990, a program was initiated to cover Slovenia with portable gamma-ray spectrometer measurements on a 5 x 5 km grid. The measurements were performed with a four channel Scintrex GAD-6 spectrometer. Five gamma-ray measurements were taken at each of 816 locations. Samples of the upper 10 cm of soil profile were collected for laboratory analysis. Uranium in samples was determinedby delayed neutron method (DNC. Other 35 elements: Ag, Al, As, Au, Ba, Be,Bi, Ca, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Sb, Se, Sn, Sr, Th, Ti,U, V, W, Y, Zn and Zr were analyzed by plasma-coupled emission spectrometry (ICP. The field gamma-ray measurements were converted to ground concentrationsof potassium, uranium and thorium. These show good correlation with the laboratory analyses of soil samples. Regardless of the wide spaced sampling, the produced maps show relatively good correlation with main geological units. They demonstrated that the methodology can be successfully implemented for environmental monitoring, geological mapping and mineral exploration. The product ofthis project is the frist natural background radioactivity map of Slovenia covering the entire country.

  17. Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Elizabeth C. Chapman,† Rosemary C. Capo,† Brian W. Stewart,*,† Carl S. Kirby,‡ Richard W. Hammack,§

    2012-02-24

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ∼375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (εSr SW = +13.8 to +41.6, where εSr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  18. A proposed new diagram for geochemical classification of natural waters and interpretation of chemical data

    Science.gov (United States)

    Chadha, D. K.

    A new hydrochemical diagram is proposed for classification of natural waters and identification of hydrochemical processes. The proposed diagram differs from the Piper and expanded Durov diagrams in that the two equilateral triangles are omitted, and the shape of the main study field is different. In addition, the proposed diagram can be constructed on most spreadsheet software packages. The proposed diagram is constructed by plotting the difference in milliequivalent percentage between alkaline earths and alkali metals, expressed as percentage reacting values, on the X axis; and the difference in milliequivalent percentage between weak acidic anions and strong acidic anions, also expressed as percentage reacting values, on the Y axis. The milliequivalent percentage differences from the X and Y co-ordinates are extended further into the main study sub-fields of the proposed diagram, which defines the overall character of water. Examples of hydrochemical analyses of groundwater are given from Karnataka, India, for each of the three types of diagrams, illustrating the applicability of the proposed diagram in four case histories having different hydrogeochemical aspects. A comparison indicates that the proposed new diagram satisfies the basic requirement for a suitable classification of natural waters, and it also can be effectively used for studies of hydrochemical processes. RésuméUn nouveau diagramme hydrochimique est proposé dans le but de classer les eaux naturelles et d'identifier les processus hydrochimiques. Ce diagramme est différent des diagrammes de Piper et de Durov étendu par le fait que les deux triangles équilatéraux sont éliminés et que la forme du principal domaine d'étude est différente. En outre, le diagramme proposé peut être construit à l'aide de la plupart des tableurs. Ce diagramme est construit à partir de la différence en pourcentage des milliéquivalents entre les alcalino-terreux et les alcalins, exprimés comme des teneurs

  19. Time-series geochemical and tracer injection recovery data from the deep (basaltic) crustal fluids from IODP Holes 1301A/1362B on the eastern flank of Juan de Fuca Ridge

    Science.gov (United States)

    Cowen, J. P.; Hsieh, C.; Guss, J.; Fisher, A. T.; Lin, H.; Clark, J. F.; Wheat, C. G.

    2012-12-01

    Integrated Ocean Drilling Program borehole CORK (Circulation Obviation Retrofit Kit) observatories provide invaluable opportunities to study the deep biosphere. In order to draw large volumes of fluids from crustal aquifers to seafloor, we developed an autonomous sensor and fluid sampling system, GeoMICROBE (Cowen et al., 2012). GeoMICROBE's Major components include a positive displacement primary pump, a primary valve manifold system, sensors (e.g., fluid flow rate, temperature, dissolved O2, electrochemistry-voltammrtry analyzer), 24-48 port in situ filtration and fluid collection system, computerized controller, six 24V-40A batteries and wet-mateable (ODI) communications with submersibles. This sampling system has been successfully deployed at IODP Hole 1301A in 2010 on the eastern flank of Juan de Fuca Ridge. The GeoMICROBE was successfully recovered in the summer of 2011. However, due to the narrow inner diameter of the fluid delivery line (1/4''), the batteries were exhausted and only half of the preprogrammed sampling procedures were accomplished. After quick turn-around the GeoMICROBE was redeployed at nearby CORK 1362B for Summer, 2012 recovery. CORKs 1301A and 1362B are only ~800 m apart and both penetrate to ~40-50m into the basement. Unlike CORK 1301A, the fluid deliver line installed on CORK 1362B has 1/2'' inner diameter. The much lower resistance allows us to pump the fluids up with reduced power consumption. A conservative power consumption model was made to ensure that enough battery power would be available to complete the twelve monthly samplings. Monthly, following extensive flushing ~3 L of fluid was passed through a 0.2 μm polycarbonate filter. The filter holder was pre-charged with 6% glutaraldehyde. Also, monthly whole fluid samples were collected and stored in an acid-washed 500mL Tedlar bag. The whole fluid will be used for analysis of colloidal (Microspheres) and dissolved tracers injected into the upper crust in August 2010 as well as

  20. Stratigraphic and geochemical controls on naturally occurring arsenic in groundwater, eastern Wisconsin, USA

    Science.gov (United States)

    Schreiber, M. E.; Simo, J. A.; Freiberg, P. G.

    High arsenic concentrations (up to 12,000μg/L) have been measured in groundwater from a confined sandstone aquifer in eastern Wisconsin. The main arsenic source is a sulfide-bearing secondary cement horizon (SCH) that has variable thickness, morphology, and arsenic concentrations. Arsenic occurs in pyrite and marcasite as well as in iron oxyhydroxides but not as a separate arsenopyrite phase. Nearly identical sulfur isotopic signatures in pyrite and dissolved sulfate and the correlation between dissolved sulfate, iron, and arsenic concentrations suggest that sulfide oxidation is the dominant process controlling arsenic release to groundwater. However, arsenic-bearing oxyhydroxides can potentially provide another arsenic source if reducing conditions develop or if they are transported as colloids in the aquifer. Analysis of well data indicates that the intersection of the SCH with static water levels measured in residential wells is strongly correlated with high concentrations of arsenic in groundwater. Field and laboratory data suggest that the most severe arsenic contamination is caused by localized borehole interactions of air, water, and sulfides. Although arsenic contamination is caused by oxidation of naturally occurring sulfides, it is influenced by water-level fluctuations caused by municipal well pumping or climate changes, which can shift geographic areas in which contamination occurs. Résumé De fortes concentrations en arsenic, jusqu'à 12000μg/L, ont été mesurées dans l'eau souterraine d'un aquifère gréseux captif, dans l'est du Wisconsin. La principale source d'arsenic est un horizon à cimentation secondaire (SCH) comportant des sulfures, dont l'épaisseur, la morphologie et les concentrations en arsenic sont variables. L'arsenic est présent dans la pyrite et dans la marcassite, de même que dans des oxy-hydroxydes de fer, mais non pas dans une phase séparée d'arsénopyrite. Les signatures isotopiques du soufre presque identiques dans la

  1. Review: Natural tracers in fractured hard-rock aquifers in the Austrian part of the Eastern Alps—previous approaches and future perspectives for hydrogeology in mountain regions

    Science.gov (United States)

    Hilberg, Sylke

    2016-08-01

    Extensive in-depth research is required for the implementation of natural tracer approaches to hydrogeological investigation to be feasible in mountainous regions. This review considers the application of hydrochemical and biotic parameters in mountain regions over the past few decades with particular reference to the Austrian Alps, as an example for alpine-type mountain belts. A brief introduction to Austria's hydrogeological arrangement is given to show the significance of fractured hard-rock aquifers for hydrogeological science as well as for water supply purposes. A literature search showed that research concerning fractured hard-rock aquifers in Austria is clearly underrepresented to date, especially when taking the abundance of this aquifer type and the significance of this topic into consideration. The application of abiotic natural tracers (hydrochemical and isotope parameters) is discussed generally and by means of examples from the Austrian Alps. The potential of biotic tracers (microbiota and meiofauna) is elucidated. It is shown that the meiofauna approach to investigating fractured aquifers has not yet been applied in the reviewed region, nor worldwide. Two examples of new approaches in mountainous fractured aquifers are introduced: (1) use of CO2 partial pressure and calcite saturation of spring water to reconstruct catchments and flow dynamics (abiotic approach), and, (2) consideration of hard-rock aquifers as habitats to reconstruct aquifer conditions (biotic approach).

  2. Spatial separation of groundwater flow paths from a multi-flow system by a simple mixing model using stable isotopes of oxygen and hydrogen as natural tracers

    Science.gov (United States)

    Nakaya, Shinji; Uesugi, Kenji; Motodate, Yusuke; Ohmiya, Isao; Komiya, Hiroyuki; Masuda, Harue; Kusakabe, Minoru

    2007-09-01

    Stable isotopes of oxygen and hydrogen have the potential to serve as tracers for both source and flow paths in a groundwater system. The ratios of stable isotopes of oxygen (δ18O) and hydrogen (δD) can be used as natural tracer parameters to separate multiflow groundwater paths by applying a simple inversion analysis method to determine the differences between observed and calculated δ18O and δD data in a simple mixing model. The model presented here assumes that the distribution of natural tracers in the steady state is governed by simple mixing between flow paths with a normal distribution of flow rate. When the inversion analysis and simple mixing model were applied to the multiflow system of the Matsumoto Basin, which is surrounded by Japanese alpine ranges, the end-members of the relationship between observed δ18O and δD could be separated spatially into specific groundwater flow paths in the multiflow system of shallow and deep groundwater flow paths.

  3. Quantification of emissions due to the natural gas storage well-casing blowout at Aliso Canyon/SS-25 using tracer flux ratio methods.

    Science.gov (United States)

    Herndon, S. C.; Daube, C.; Jervis, D.; Yacovitch, T. I.; Roscioli, J. R.; Curry, J.; Nelson, D. D.; Knighton, W. B.

    2016-12-01

    The methane emission rate from the well blowout at Aliso Canyon Natural Gas Storage Facility in Porter Ranch, California was quantified using the tracer flux ratio method (TFR). Over 400 tracer plume transects were collected, each lasting 15-300 seconds, using instrumentation aboard a mobile platform on 25 days between December 21, 2015 and March 9, 2016. The leak rate from October 23rd to February 11th has been estimated here using a combination of our leak rate measurements (TFR) and the flight mass balance (FMB) data [Conley et al., 2016]. The TFR approach employed here is assessing only the leaks due to the SS-25 well blowout and excludes other possible emissions at the facility. By "calibrating" the FMB dataset, the leak rate is integrated from Oct 23rd to December 21th. The sum of the inferred inferred and measured meissions suggests a total leak burden of 86,022 ± 8,393 metric tons of CH4. The primary uncertainty in this value is due to the uncertainty in the emission rate prior to the beginning of the TFR quantification. The ethane to methane enhancement ratio observed downwind of the leak site is consistent with the content of ethane in the natural gas at this site and provides definitive evidence that the methane emission rate quantified via tracer flux ratio is not due to a nearby landfill or other potential biogenic sources.

  4. Formation and geochemical significance of micrometallic aggregates including fissiogenic platinum group elements in the Oklo natural reactor, Gabon

    Science.gov (United States)

    Kikuchi, Makiko; Hidaka, Hiroshi; Gauthier-Lafaye, François

    2010-08-01

    Metallic aggregates with a size of a few tens μm and consisting mainly of Ru, Rh, Pd, Te, Pb, As, Sb, S and Bi were found in the acid residue of SD37-S2/CD uraninite taken from Oklo natural reactor zone (RZ) 13. Quantitative analyses of major elements using an electron probe microanalyzer and in situ isotopic analyses of Zr, Mo, Ru, Pb and U using a sensitive high-resolution ion microprobe were performed on the metallic aggregates to determine the geochemical behaviors of fission products and actinides and to ascertain the processes of formation of the aggregates in the RZs. The chemical compositions of the aggregates investigated in this study are significantly different from those reported previously, showing lower Pb content and no correlation between the contents of Pb and S in the individual grains. The 235U/ 238U ratios in metallic aggregates vary significantly from 0.00478 to 0.01466, indicating chemical fractionation between U and Pu during the formation of the aggregates. The Pb isotopic data indicate that most of the Pb in the aggregates decayed from 2.05 Ga-old uraninite that existed in the RZ originally and that there was chemical fractionation between U and Pb in some aggregates. The Zr and Mo isotopic ratios, 90Zr/ 91Zr and 95Mo/ 97Mo, for most of the aggregates had small variations, which can be simply explained by constant separate mixing of fissiogenic and nonfissiogenic components. On the other hand, a large variation in the 99Ru/ 101Ru ratio (0.324-1.73) cannot be explained only by a two component mixing theory; thus, chemical fractionation between Tc and Ru during the reactor criticality is suggested. The large variations in the 235U/ 238U and 99Ru/ 101Ru isotopic ratios suggest that the aggregates formed under various redox conditions owing to the radiolysis of water.

  5. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110462 Chen Furong(Anhui Institute of Geological Survey,Hefei 230001,China)Ore-Search Prospects of Gold and Tungsten Geochemical Anomalies in Ningdun Area,Anhui Province(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,34(2),2010,p.150-153,5 illus.,2 tables,6 refs.)Key words:gold ores,tungsten ores,geochemical exploration,AnhuiGeochemical anomalies of gold and tungsten in Ningdun area are dominated by the element association of Au-As-W-Bi.These anomalies are well coincident with

  6. Environmental Tracers

    Directory of Open Access Journals (Sweden)

    Trevor Elliot

    2014-10-01

    Full Text Available Environmental tracers continue to provide an important tool for understanding the source, flow and mixing dynamics of water resource systems through their imprint on the system or their sensitivity to alteration within it. However, 60 years or so after the first isotopic tracer studies were applied to hydrology, the use of isotopes and other environmental tracers are still not routinely necessarily applied in hydrogeological and water resources investigations where appropriate. There is therefore a continuing need to promote their use for developing sustainable management policies for the protection of water resources and the aquatic environment. This Special Issue focuses on the robustness or fitness-for-purpose of the application and use of environmental tracers in addressing problems and opportunities scientifically, to promote their wider use and to address substantive issues of vulnerability, sustainability, and uncertainty in (groundwater resources systems and their management.

  7. Assessing vulnerability mapping and protection zones of karst spring waters and validating by the joint use of natural and artificial tracers. The case of Auta Spring (Southern Spain)

    Science.gov (United States)

    Marín, Ana Isabel; Mudarra, Matías; Andreo, Bartolomé

    2016-04-01

    Delineation of protection zones for water supply and implementation of proper land-use practices in surrounding areas are crucial aspects for a sustainable use of valuable drinking water resources. This is even more important in karst aquifers, which are particularly sensitive to contamination, having a very low self-cleaning capacity due to their structure and hydrological behavior. Consequently, specific methodologies adapted to the particular characteristics of karst media are necessary. In this work, an approach for protection zoning of the pilot site of Auta karst spring (southern Spain) is proposed, based on the application of COP+K method for contamination vulnerability and validation of results by natural (organic) tracers of infiltration (NO3-, TOC, intrinsic fluorescence) and by a dye tracer test conducted on June, 2011 (injecting 500 mg uranine). The aquifer drained by Auta spring (8.5 km2) presents a complex geological structure, formed by Jurassic dolostones and limestones highly folded and fractured. Recharge takes place by the infiltration of rainfall through karst landforms and also by losses in an adjacent river when it flows over the carbonate outcrops (dye injection point). Drainage is mainly through several springs located at the southwest, including Auta spring and 5 overflow springs. The source vulnerability map obtained by applying COP+K method can be adopted as the baseline to delineate the protection zones, through the conversion from vulnerability classes to degrees of protection. Dye tracer test and natural tracers of infiltration corroborate that aquifer sectors influenced by the river can be extremely vulnerable to pollution, but also well-developed exokarst features. In fact, slight evidences of pollution have been detected during the study period, with relatively-high NO3- contents and high fluorescence linked to bacteriological activity in Auta spring water. The jointly use of natural and artificial tracers constitute a reliable and

  8. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>20081182 Chen Guoguang(China University of Geosciences,Wuhan 430074,China);Zhou Guohua Eco-Geochemical Assessment Based On Geosciences(Resources Survey & Environment,ISSN1671-4814,CN32-1640/N,28(2),2007,p.79-84,2 tables,6 refs.)Key words:regional geochemical

  9. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131784 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China);Lei Yingping Geochemical Characteristics and Metallogenic Prospecting Areas in Yunkai Area,Guangxi(Geophysical and Geochemical Exploration,ISSN1000-8918,CN11-1906/P,36

  10. Combined use of natural and artificial tracers to determine the hydrogeological functioning of a karst aquifer: the Villanueva del Rosario system (Andalusia, southern Spain)

    Science.gov (United States)

    Mudarra, M.; Andreo, B.; Marín, A. I.; Vadillo, I.; Barberá, J. A.

    2014-08-01

    Analysis of natural responses of karst springs provides information on the behavior of the aquifers they drain. Detailed monitoring and qualitative and quantitative analyses of natural responses, and environmental—total organic carbon (TOC), NO3 -, Cl- and intrinsic fluorescence—and artificial (fluorescent dye) tracers, in the water drained by Villanueva del Rosario spring (southern Spain), suggest the existence of a conduit flow system with rapid flows and very short transit times of water through the aquifer. This is in agreement with uranine and eosin breakthrough curves and with simple numerical models done using these data. However, due to the low capacity for natural regulation, not all the recharge effects are simultaneously transmitted to the spring water; given a single input, the system modulates and transfers hydrodynamic variations faster than variations of chemical composition and of water temperature. Additionally, time lags between maximum concentrations of natural and artificial tracers show that the global system response (including diffuse infiltration) is faster and more sensitive than that produced from infiltration concentrated at a single point on the surface (sinkholes).

  11. Tracer-/Heat transfer decoupling in a heterogenous, fault zone based hydrothermal reservoir in the Upper Rhine Basin; Tracer-/Waermetrnasportentkopplung in einem heterogenen, stoerungszonengepraegten Hydrothermalreservoir im Oberrheingraben

    Energy Technology Data Exchange (ETDEWEB)

    Ghergut, I.; Licha, T.; Maier, F.; Nottebohm, M.; Sauter, M. [Goettingen Univ. (Germany). Abt. Angewandte Geologie; Meixner, J.; Rettenmaier, D. [Karlsruher Institut fuer Technologie (KIT) (Germany). Abt. Hydrogeologie

    2012-10-16

    Heat transport processes and tracer transport processes probe the boundaries of a tracer based prognosis of the thermal lifetime for a geothermal borehole doublet in a heterogeneous hydrothermal reservoir in the Upper Rhine Basin whose behaviour is characterized by two or three large-scale not bored fault zones. A hydro-geologic structure model of the reservoir is the fundament for the identification of decisive fluid transport processes. The thermal breakdown is a rather abstract threatening with a large time distance for the geothermal borehole doublet. Nearby dangers of hydro-geochemical and hydro-mechanical nature require tracer tests for their quantification. Long dwell times are expected in a circulation test, while interpretation difficulties are expected in early tracer signals. Heat-push-shut-in tests or tracer-push-flowback tests at the geothermal re-injection drilling can supply information on transport effective aquifer parameters in an even more appropriate time. A fluid transport based characterization of the fault zones is only imaginable by means of long-term circulation tests with conservative and thermo-sensitive tracers.

  12. IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

    Science.gov (United States)

    Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

  13. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091835 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Zhuang Guangmin The Cd Geochemical Province in the Source Area of the Yangtze River and the Output Fluxes of Cd for Its Major Water Systems(Earth Science Frontiers,ISSN1005-2321,CN11-3370/P,15(5),2008,p.203-211,5 illus.,5 tables,25 refs.,with English abstract)Key words:cadmium,geochemical province,Qinghai-Tibetan Plateau20091836 Cheng Hangxin(School of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China);Yang Zhongfang A New Round of Global Geochemical

  14. The applicability and limitations of the geochemical models and tools used in simulating radionuclide behaviour in natural waters. Lessons learned from the Blind Predictive Modelling exercises performed in conjunction with Natural Analogue studies

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.; Duro, L.; Grive, M. [QuantiSci SL, Parc Tecnologic del Valles (Spain)

    2001-07-01

    One of the key applications of Natural Analogue studies to the Performance Assessment (PA) of nuclear waste disposal has been the possibility to test the geochemical models and tools to be used in describing the migration of radionuclides in a future radioactive waste repository system. To this end, several geochemical modelling testing exercises (commonly denoted as Blind Predictive Modelling), have formed an integral part of Natural Analogue Studies over the last decade. Consequently, we thought that this is a timely occasion to make an evaluation of the experience gained and lessons learnt. We have reviewed, discussed and compared the results obtained from the Blind Prediction Modelling (BPM) exercises carried out within 7 Natural Analogue Studies: Oman, Pocos de Caldas, Cigar Lake, Maqarin, El Berrocal, Oklo and Palmottu. To make this comparison meaningful, we present the main geochemical characteristics of each site in order to highlight the most relevant mineralogical and hydrochemical differences. From the complete list of elements studied at all the investigated sites we have made a selection based on the relevance of a given element from a PA viewpoint and on the frequency this element has been included in the BPM exercises. The elements selected for discussion are: Sr, Ba, Sn, Pb, Se, Ni, Zn, REEs, Th and U. We have based our discussion on the results obtained from the speciation as well as solubility calculations. From the comparison of the results it is concluded that we can differentiate between three element categories: 1. Elements whose geochemical behaviour can be fairly well described by assuming solubility control exerted by pure solid phases of the given element (i.e. Th, U under reducing conditions and U in some sites under oxidising conditions); 2. Elements for which the association to major geochemical components of the system must be considered in order to explain their concentrations in groundwaters (i.e. Sr, Ba, Zn, Se, REEs and U under

  15. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152642 Baoyinwuliji(Inner Mongolia Institute of Geological Survey,Hohhot 010020,China);Zhao Wentao Geochemical Anomaly and Metallogenic Potential of the Naomugengsumu Lithium Mineralization Area in Inner Mongolia(Geology and Resources,ISSN1671

  16. Identification of Sediment Sources to Calumet River through Geochemical Fingerprinting

    Science.gov (United States)

    2017-04-01

    Other Tracers for Dredged Material Fate” ERDC TR-17-1 ii Abstract Geochemical sedimentary markers provide a well-established methodology for...12 Principal component analysis...22 Principal component analysis (PCA

  17. Geochemical constraints on the nature of magma sources for Triassic granitoids from South Qinling in central China

    Science.gov (United States)

    Lu, Ying-Hui; Zhao, Zi-Fu; Zheng, Yong-Fei

    2017-07-01

    A combined study of zircon U-Pb ages and Lu-Hf isotopes, whole-rock major-trace elements and Sr-Nd isotopes as well as mineral chemistry and O isotopes was carried out for Triassic granitoids from the South Qinling orogen in central China. Model calculations were also performed to examine the trace element fractionation during partial melting of crustal rocks. The results provide insights into the nature of magma sources for these granitoids. LA-ICPMS zircon U-Pb dating yields concordant ages of 208 ± 2 to 216 ± 3 Ma for these granitoids from the Shahewan (SHW), Caoping (CP) and Zhashui (ZS) plutons, and no relict zircon cores are identified by the CL imaging and U-Pb dating. The SHW and CP granitoids contain hornblende and are metaluminous with A/CNK ratios of 0.84 to 0.93. They exhibit relatively low SiO2 contents (62.88-69.04 wt.%) but high contents of FeOT, MgO and TiO2, and slightly to negligibly negative Eu anomalies (δEu = 0.79-0.89). Zircons from them show mantle-like δ18O values of 4.71 to 5.72‰. In contrast, the ZS granites contain no hornblende and are metaluminous to weakly peraluminous with A/CNK ratios of 0.99 to 1.03. They show relatively high SiO2 contents (69.32-75.94 wt.%) but low FeOT, MgO and TiO2 contents, and moderate negative Eu anomalies (δEu = 0.63-0.81). They have slightly low zircon δ18O values of 4.60 to 4.83‰. All of these granitoids show arc-like trace element distribution patterns with enrichment in LREE and LILE (e.g., Rb, K and Pb) but depletion in HFSE (e.g., Nb, Ta and Ti). Geochemical comparison and modeling indicate that these granitoids are different from adakitic rocks originating from the thickened lower continental crust. Compared with the composition of felsic melts produced by petrological experiments of various lithologies, it appears that these granitoids are derived from dehydration melting of metabasaltic sources at normal lower crustal depths, and experienced varying degrees of fractional crystallization

  18. Radiation-Induced Defects in Kaolinite as Tracers of Past Occurrence of Radionuclides in a Natural Analogue of High Level Nuclear Waste Repository

    Science.gov (United States)

    Allard, T.; Fourdrin, C.; Calas, G.

    2007-05-01

    Understanding the processes controlling migrations of radioelements at the Earth's surface is an important issue for the long-term safety assessment of high level nuclear waste repositories (HLNWR). Evidence of past occurrence and transfer of radionuclides can be found using radiation-induced defects in minerals. Clay minerals are particularly relevant because of their widespread occurrence at the Earth's surface and their finely divided nature which provides high contact area with radioactive fluids. Owing to its sensitivity to radiations, kaolinite can be used as natural, in situ dosimeter. Kaolinite is known to contain radiation-induced defects which are detected by Electron Paramagnetic Resonance. They are differentiated by their nature, their production kinetics and their thermal stability. One of these defects is stable at the scale of geological periods and provides a record of past radionuclide occurrence. Based on artificial irradiations, a methodology has been subsequently proposed to determine paleodose cumulated by kaolinite since its formation. The paleodose can be used to derive equivalent radioelement concentrations, provided that the age of kaolinite formation can be constrained. This allows quantitative reconstruction of past transfers of radioelements in natural systems. An example is given for the Nopal I U-deposit (Chihuahua, Mexico), hosted in hydrothermally altered volcanic tufs and considered as analogue of the Yucca Mountain site. The paleodoses experienced by kaolinites were determined from the concentration of defects and dosimetry parameters of experimental irradiations. Using few geochemical assumption, a equivalent U-content responsible for defects in kaolinite was calculated from the paleodose, a dose rate balance and model ages of kaolinites constrained by tectonic phases. In a former study, the ages were assumptions derived from regional tectonic events. In thepresent study, ages of mineralization events are measured from U

  19. Metal stable isotope signatures as tracers in environmental geochemistry.

    Science.gov (United States)

    Wiederhold, Jan G

    2015-03-03

    The biogeochemical cycling of metals in natural systems is often accompanied by stable isotope fractionation which can now be measured due to recent analytical advances. In consequence, a new research field has emerged over the last two decades, complementing the traditional stable isotope systems (H, C, O, N, S) with many more elements across the periodic table (Li, B, Mg, Si, Cl, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Ge, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, Te, Ba, W, Pt, Hg, Tl, U) which are being explored and potentially applicable as novel geochemical tracers. This review presents the application of metal stable isotopes as source and process tracers in environmental studies, in particular by using mixing and Rayleigh model approaches. The most important concepts of mass-dependent and mass-independent metal stable isotope fractionation are introduced, and the extent of natural isotopic variations for different elements is compared. A particular focus lies on a discussion of processes (redox transformations, complexation, sorption, precipitation, dissolution, evaporation, diffusion, biological cycling) which are able to induce metal stable isotope fractionation in environmental systems. Additionally, the usefulness and limitations of metal stable isotope signatures as tracers in environmental geochemistry are discussed and future perspectives presented.

  20. Use of Natural Tracers for Understanding Porewater Residence Time and Solute Transport: Challenges Encountered in Paleozoic Rocks of the Michigan Basin

    Science.gov (United States)

    Al, T. A.; Celejewski, M.; Clark, I. D.

    2014-12-01

    Geoscience programs that focus on long-term waste management in the geosphere commonly aim to develop a conceptual model that explains porewater residence time and the mechanisms and time scales for solute transport. Diffusion is the dominant transport process in low-permeability rocks so measurement of rock diffusion properties is important, but measurements at the laboratory scale can be highly variable due to changes in lithology, porosity, confining pressure and pore-fluid composition at scales of cm to 10's of m. The natural analogue approach, using tracers such as Cl, Br, 18O and 2H that commonly display conservative behaviour, provides a means to scale up the results of laboratory measurements to understand the larger-scale controls on porewater residence time and solute transport. The principal challenge in applying this approach is the difficulty of obtaining high-quality tracer concentration data from porewater in low-permeability rocks. Additional insight into solute transport and reaction processes could be gained by collecting data for the concentrations of major cations but these data are even more difficult to obtain. Using data from the geoscience site characterization for the Ontario Power Generation proposed Deep Geologic Repository at the Bruce site in southwest Ontario, this presentation will illustrate some of the problems with standard methods for obtaining porewater compositional data . Methods such as core squeezing and advective displacement simply do not work because the permeability and the water content are too low. The crush-leach method has been used but is susceptible to artifacts from dissolution of soluble minerals (halite, anhydrite, gypsum and celestite), ion exchange and difficulty in assigning a porosity value to specific solutes. In order to overcome these limitations and improve the outcome from the natural analogue approach, a new method has been developed that extracts porewater directly into hydrophyllic cellulosic paper by

  1. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20151884 An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing100083,China)Regional Geochemistry of Sanjiang Region in Yunnan Province and Its Copper-Polymetallic Prospecting Significance(Geophysical and Geochemical Exploration,ISSN1000-8918,

  2. Questa baseline and pre-mining ground-water quality investigation. 12. Geochemical and reactive-transport modeling based on tracer injection-synoptic sampling studies for the Red River, New Mexico, 2001-2002

    Science.gov (United States)

    Ball, James W.; Runkel, Robert L.; Nordstrom, D. Kirk

    2005-01-01

    Reactive-transport processes in the Red River, downstream from the town of Red River in north-central New Mexico, were simulated using the OTEQ reactive-transport model. The simulations were calibrated using physical and chemical data from synoptic studies conducted during low-flow conditions in August 2001 and during March/April 2002. Discharge over the 20-km reach from the town of Red River to the USGS streamflow-gaging station near the town of Questa ranged from 395 to 1,180 L/s during the 2001 tracer and from 234 to 421 L/s during the 2002 tracer. The pH of the Red River ranged from 7.4 to 8.5 during the 2001 tracer and from 7.1 to 8.7 during the 2002 tracer, and seep and tributary samples had pH values of 2.8 to 9.0 during the 2001 tracer and 3.8 to 7.2 during the 2002 tracer. Mass-loading calculations allowed identification of several specific locations where elevated concentrations of potential contaminants entered the Red River . These locations, characterized by features on the north side of the Red River that are known to be sources of low-pH water containing elevated metal and sulfate concentrations, are: the initial 2.4 km of the study reach, including Bitter Creek, the stream section from 6.2 to 7.8 km, encompassing La Bobita well and the Hansen debris fan, Sulphur Gulch, at about 10.5 km, the area near Portal Springs, from 12.2 to 12.6 km, and the largest contributors of mass loading, the 13.7 to 13.9 km stream section near Cabin Springs and the 14.7 to 17.5 km stream section from Shaft Spring to Thunder Bridge, Goathill Gulch, and Capulin Canyon. Speciation and saturation index calculations indicated that although solubility limits the concentration of aluminum above pH 5.0, at pH values above 7 and aluminum concentrations below 0.3 mg/L inorganic speciation and mineral solubility controls no longer dominate and aluminum-organic complexing may occur. The August 2001 reactive-transport simulations included dissolved iron(II) oxidation, constrained

  3. Of the necessity of knowledge of the natural pedo-geochemical background content in the evaluation of the contamination of soils by trace elements.

    Science.gov (United States)

    Baize, D; Sterckeman, T

    2001-01-08

    In order to evaluate the contamination of the Dornach (Switzerland) site within the framework of the CEEM-Soil project, each participating team was allowed to take a maximum of 15 samples. The French team's sampling was organized in such a way as to answer the following questions: (i) what is the natural concentration of the soils at this site (local pedo-geochemical background content)?; (ii) what are the levels of Cd, Cu, Pb and Zn contamination of the soil?; (iii) what is the depth reached by the surface contamination that is derived from atmospheric fallout?; (iv) how is the contamination spread along the longest axis of the area under study? The relationships between total Fe and the trace metals have allowed local variations in the natural pedo-geochemical background content to be detected and thus permitted the anthropogenic contamination to be estimated. There would appear to be a low level of Pb contamination over all the site investigated (an increase of the order of 5-10 mg kg(-1) on the background level), limited to the surface humus-bearing layers. There is also a significant contamination by Cu over all of the site (an increase of the order of 30-40 mg kg(-1)). This contamination has remained in the surface horizons (0-20 cm). Very high Zn and Cd concentrations have been found in the four surface (0-4 cm) and deep horizons (15-70 cm) taken under the forest and very much lower values in the samples taken from cultivated soils. The most likely explanation is an unequal inheritance between the upper part of the site (wooded with thinner very clayey soils) and the lower cultivated part of the site (with thicker less clayey soils developed in a loamy material). For various reasons, it seems unlikely that a contamination of the wooded part should be so much higher than the cultivated part due to the interception of atmospheric dust by the trees. The local pedo-geochemical background Cd and Zn content of the upper wooded part proved to be clearly higher than

  4. Experimental and numerical investigation of the tracer gas methodology in the case of a naturally cross-ventilated building

    DEFF Research Database (Denmark)

    Larsen, Tine Steen; Νikolopoulos, Nikos; Nikolopoulos, Aristeidis;

    2012-01-01

    This paper presents the investigation of a naturally cross-ventilated building using both experimental and numerical methods with parameter being the incidence angle of the wind to the openings of the building. The experimental methodology calculates the air change rate based either on measurements...... on the time dependent character of the induced flow field. The numerical results are compared with corresponding experimental data for the three aforementioned experimental methodologies in the case of a full-scale building inside a wind tunnel. The numerical investigation reveals that for large incidence...

  5. Inorganic contaminants from diffuse pollution in shallow groundwater of the Campanian Plain (Southern Italy). Implications for geochemical survey.

    Science.gov (United States)

    Cuoco, E; Darrah, T H; Buono, G; Verrengia, G; De Francesco, S; Eymold, W K; Tedesco, D

    2015-02-01

    The Campanian Plain (CP) shallow aquifer (Southern Italy) represents a natural laboratory to validate geochemical methods for differentiating diffuse anthropogenic pollution from natural water-rock interaction processes. The CP is an appropriate study area because of numerous potential anthropogenic pollution vectors including agriculture, animal husbandry, septic/drainage sewage systems, and industry. In order to evaluate the potential for geochemical methods to differentiate various contamination vectors, 538 groundwater wells from the shallow aquifer in Campanian Plain (CP) were sampled. The dataset includes both major and trace elements. Natural water-rock interactions, which primarily depend on local lithology, control the majority of geochemical parameters, including most of the major and trace elements. Using prospective statistical methods in combination with the traditional geochemical techniques, we determined the chemical variables that are enriched by anthropogenic contamination (i.e. NO3, SO4 and U) by using NO3 as the diagnostic variable for detecting polluted groundwater. Synthetic agricultural fertilizers are responsible for the majority of SO4 and U pollution throughout the CP area. Both SO4 and U are present in the groundmass of synthetic fertilizers; the uranium concentration is specifically applicable as a tracer for non-point source agricultural fertilizer contamination. The recognition of non-geological (anthropogenic) inputs of these elements has to be considered in the geochemical investigations of contaminated aquifers.

  6. Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill samples from the Powder River basin, Wyoming

    Science.gov (United States)

    See, R.B.; Reddy, K.J.; Vance, G.F.; Fadlelmawla, A.A.; Blaylock, M.J.

    1995-01-01

    Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill aquifers were investigated. Backfill and ground-water samples were collected at coal mines in the Powder River Basin, Wyoming. Backfill was generally dominated by aluminum (14,400 to 49,000 mg/kg (milligrams per kilogram)), iron (3,330 to 23,200 mg/kg), and potassium (7,950 to 18,000 mg/kg). Backfill saturated-paste selenium concentrations ranged from 1 to 156 mg/kg (microsiemens per kilogram). Ground-water total selenium concentrations ranged from 3 to 125 mg/L. Dissolved organic carbon in all ground-water samples was dominated by hydrophobic and hydrophilic acids (38 to 84 percent). Selenite sorption/desorption experiments were conducted using background solutions of distilled-deionized water, 0.1 molar calcium chloride, and isolated hydrophobic and hydrophilic acids. Selenite sorption was larger when 0.1 molar calcium chloride was used. The addition of hydrophilic acid decreased selenite sorption more than the addition of hydrophobic acids. Geochemical modelling was used to predict the solid phases controlling dissolved selenium concentrations and to evaluate the effects of dissolved organic carbon on selenium solubility. Results suggested that 55 to 90 percent of selenium in backfill precipitation/dissolution extracts was dominated by magnesium selenate ion pairs. Dissolved organic carbon had little effect on selenium speciation. A redox chamber was constructed to control Eh and pH in water and backfill-core sample suspensions. The response of selenite and selenate in water samples to redox conditions did not follow thermodynamic predictions. Reduction of selenate in water samples did not occur at any of the redox levels tested.

  7. Distribution and geochemical characterization of coalbed gases at excavation fields at natural analogue site area Velenje Basin, Slovenia

    Science.gov (United States)

    Kanduč, Tjaša; Žigon, Stojan; Grassa, Fausto; Sedlar, Jerneja; Zadnik, Ivo; Zavšek, Simon

    2016-04-01

    Unconventional gas resources, including coal bed methane and shale gas, are a growing part of the global energy mix, which has changed the economic and strategic picture for gas consuming and producing countries, including the USA, China and Australia that, together are responsible for around half the currently recoverable unconventional gas resources. However, CBM production was often hindered by low permeability and mineralization in cleats and fractures, necessitating the development of cost effective horizontal drilling and completion techniques. Geochemical and isotopic monitoring of coalbed gases at excavation fields in Velenje Basin started in year 2000, with the aim to obtain better insights into the origin of coalbed gases. Results from active excavation fields in the mining areas Pesje and Preloge in the year period 2014-2015 are presented in this study. Composition and isotopic composition of coalbed gases were determined with mass - spectrometric methods. The chemical (methane, carbon dioxide, nitrogen) and isotopic composition of carbon in methane and carbon dioxide in the Velenje Basin vary and depend on the composition of the source of coalbed gas before excavation, advancement of the working face, depth of the longwall face, pre-mining activity and newly mined activity. The basic gas components determined in excavation fields are carbon dioxide and methane. Knowledge of the stable isotope geochemistry of coal bed and shale gas and the related production water is essential to determine not only gas origins but also the dominant methanogenic pathway in the case of microbial gas. Concentrations of methane at active excavation fields are changing from 1.8 to 63.9 %, concentrations of carbon dioxide are changing from 36.1 to 98.2% and CDMI (Carbon Dioxide Methane Index) index from 0.2 to 100 %. Isotopic composition of carbon dioxide is changing from -11.0 to -1.9‰ , isotopic composition of methane from -71.8 to -43.3‰ , isotopic composition of

  8. Migration, filling history and geochemical characteristics of Ordovician natural gases in the Tahe Oilfield, Tarim Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    WANG Jie; LIU Wenhui; QIN Jianzhong; LIU Keyu; GU Yi

    2009-01-01

    Ordovician natural gases in the Tahe Oilfield are composed predominantly of hydrocarbon gases dominated by methane with a significant amount of heavy hydrocarbon gas component. The non-hydrocarbon gases include N2, CO2 and minor H2S. The Ordovician natural gases are believed to have originated from the same source rocks, and are composite of gases differing in thermal maturity. Carbon dioxide was derived from thermal metamorphism of Ordovician carbonate rocks. The generation of natural gases involves multiple stages from mature normal oil and condensate-associated gas to thermally cracked gas at the maturity to over-maturity stages. In the main part of the Tahe Oilfield, the Ordovician natural gases appear to be filled in two major phases with a typical petroleum-associated gas from southeast to northwest and from east to west in the early stage; and a thermally cracked gas from east to west in the late stage. At the same time, the oil/gas filling boundary has been primarily established between the two stages.

  9. Geochemical features and genesis of the natural gas and bitumen in paleo-oil reservoirs of Nanpanjiang Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO MengJun; ZHANG ShuiChang; ZHAO Lin; DA Jiang

    2007-01-01

    Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argillaceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000-4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows.

  10. Geochemical features and genesis of the natural gas and bitumen in paleo-oil reservoirs of Nanpanjiang Basin, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Bitumen from the Nanpanjiang Basin occurs mainly in the Middle Devonian and Upper Permian reef limestone paleo-oil reservoirs and reserves primarily in holes and fractures and secondarily in minor matrix pores and bio-cavities. N2 is the main component of the natural gas and is often associated with pyrobitumen in paleo-oil reservoirs. The present study shows that the bitumen in paleo-oil reservoirs was sourced from the Middle Devonian argillaceous source rock and belongs to pyrobitumen by crude oil cracking under high temperature and pressure. But the natural gas with high content of N2 is neither an oil-cracked gas nor a coal-formed gas generated from the Upper Permian Longtan Formation source rock, instead it is a kerogen-cracked gas generated at the late stage from the Middle Devonian argilla- ceous source rock. The crude oil in paleo-oil reservoirs completely cracked into pyrobitumen and methane gas by the agency of hugely thick Triassic deposits. After that, the abnormal high pressure of methane gas reservoirs was completely destroyed due to the erosion of 2000--4500-m-thick Triassic strata. But the kerogen-cracked gas with normal pressure was preserved under the relatively sealed condition and became the main body of the gas shows.

  11. Geochemical behavior of radionuclides in highly altered zircon above the Bangombé natural fission reactor, Gabon

    Science.gov (United States)

    Kikuchi, Makiko; Hidaka, Hiroshi; Horie, Kenji

    The isotopic compositions of rare earth elements (REE), Pb and U of highly altered zircons from the clay and black shale layers above the Bangombé natural reactor, Gabon, were determined by a sensitive high resolution ion microprobe (SHRIMP) to discuss the redistribution processes of elements into zircons under the supergene weathering. The clay layer trapped most of the fissiogenic Nd, Sm and Eu derived from the reactor and prevented them migrating into the black shale layer. On the other hand, only the Ce isotopic ratios of the clay and black shale layers have about 2 times larger variations than the other REE. This result suggests that a large chemical fractionation between Ce and other REE above the reactor occurred under the oxidizing condition. The U-Pb data of zircons suggest that the U-Pb system was largely disturbed by migration of chemically fractionated Pb and U from the 2.0 Ga-old uraninite in association with recent weathering.

  12. Coupled Ge/Si and Ge isotope ratios as geochemical tracers of seafloor hydrothermal systems: Case studies at Loihi Seamount and East Pacific Rise 9°50‧N

    Science.gov (United States)

    Escoube, Raphaelle; Rouxel, Olivier J.; Edwards, Katrina; Glazer, Brian; Donard, Olivier F. X.

    2015-10-01

    Germanium (Ge) and Silicon (Si) exhibit similar geochemical behavior in marine environments but are variably enriched in seafloor hydrothermal fluids relative to seawater. In this study, Ge isotope and Ge/Si ratio systematics were investigated in low temperature hydrothermal vents from Loihi Seamount (Pacific Ocean, 18°54‧N, 155°15‧W) and results were compared to high-temperature vents from the East Pacific Rise (EPR) at 9°50‧N. Loihi offers the opportunity to understand contrasting Ge and Si behavior in low temperature seafloor hydrothermal systems characterized by abundant Fe oxyhydroxide deposition at the seafloor. The results show that both Ge/Si and δ74/70Ge in hydrothermal fluids are fractionated relative to the basaltic host rocks. The enrichment in Ge vs. Si relative to fresh basalts, together with Ge isotope fractionation (Δ74/70Gefluid-basalt up to 1.15‰ at EPR 9°50‧N and 1.64‰ at Loihi) are best explained by the precipitation of minerals (e.g. quartz and Fe-sulfides) during higher temperature seawater-rock reactions in the subsurface. The study of Fe-rich hydrothermal deposits at Loihi, largely composed of Fe-oxyhydroxides, shows that Ge isotopes are also fractionated upon mineral precipitation at the seafloor. We obtained an average Ge isotope fractionation factor between Fe-oxyhydroxide (ferrihydrite) and dissolved Ge in the fluid of -2.0 ± 0.6‰ (2sd), and a maximum value of -3.6 ± 0.6‰ (2sd), which is consistent with recent theoretical and experimental studies. The study of a hydrothermal chimney at Bio 9 vent at EPR 9°50‧N also demonstrates that Ge isotopes are fractionated by approximately -5.6 ± 0.6‰ (2sd) during precipitation of metal sulfides under hydrothermal conditions. Using combined Ge/Si and estimated Ge isotope signatures of Ge sinks and sources in seawater, we propose a preliminary oceanic budget of Ge which reveals that an important sink, referred as the "missing Ge sink", may correspond to Ge sequestration

  13. Asphalt Volcanism as a Model to Understand the Geochemical Nature of Pitch Lake, a Planetary Analog for Titan and the Implications towards Methane Flux into Earth's Atmosphere.

    Science.gov (United States)

    Khan, A.

    2016-12-01

    Pitch Lake is located in the southwest peninsula of the island near La Brea in Trinidad and Tobago, covering an area of approximately 46 hectares. It was discovered in the year 1595 and is the largest of three natural asphalt lakes that exist on Earth. Pitch Lake is a large oval shaped reservoir composed of dominantly hydrocarbon compounds, but also includes minor amounts of clay and muddy water. It is a natural liquid asphalt desert, which is nourished by a form of petroleum consisting of mostly asphaltines from the surrounding oil-rich region. The hydrocarbons mix with mud and gases under high pressure during upward seepage, and the lighter portion evaporates or is volatilized, which produces a high-viscosity liquid asphalt residue. The residue on and near the surface is a hydrocarbon matrix, which poses extremely challenging environmental conditions to microorganisms characterized by an average low water activity in the range of 0.49 to 0.75, recalcitrant carbon substrates, and toxic chemical compounds. Nevertheless, an active microbial community of archaea and bacteria, many of them novel strains, was found to inhabit the liquid hydrocarbon matrix of Pitch Lake. Geochemical analyses of minerals, done by our team, which revealed sulfates, sulfides, silicates, and metals, normally associated with deep-water hydrothermal vents leads to our new hypothetical model to describe the origins of Pitch Lake and its importance to atmospheric and earth sciences. Pitch Lake is likely the terrestrial equivalent of an offshore submarine asphalt volcano just as La Brea Tar Pits are in some ways an on-land version of the asphalt volcanoes discovered off shore of Santa Barbara by Valentine et al. in 2010. Asphalt volcanism possibly also creates the habitat for chemosynthetic life that is widespread in this lake, as reported by Schulze-Makuch et al. in 2011 and Meckenstock et al. in 2014.

  14. GEOCHEMICAL EXPLORATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111167 Cao Zhonghuang(Wuhan Iron & Steel Group Minerals Company,Wuhan 430063,China);Luo Xianrong Comparative Study of Copper-Nickel Deposit Exploration by the Geoelectro-chemical Extraction Method in Different Overburden Areas(Geology and Prospecting,ISSN0495-5331,CN11-2043/P,46(3),2010,p.476-482,4 illus.,5 tables,20 refs.)Key words:geo-electrochemical methods,copper ores,nickel ores,Gansu Province,Jilin Province The authors have made a comparative study of quantitative and qualitative analysis and application of the geoelectro-chemical extraction method in different overburden areas in southward extension of Jinchuan in Gansu Province and Hongqiling in Jilin Province.The authors found that this method extracted very few ions in arid areas covered with debris,but the prospecting effect was almost the same as that in moist areas covered with thick overburden.And this method could show objectively differences of geochemical characters

  15. Geophysical and geochemical nature of relaminated arc-derived lower crust underneath oceanic domain in southern Mongolia

    Science.gov (United States)

    Guy, Alexandra; Schulmann, Karel; Janoušek, Vojtech; Štípská, Pavla; Armstrong, Robin; Belousova, Elena; Dolgopolova, Alla; Seltmann, Reimar; Lexa, Ondrej; Jiang, Yingde; Hanžl, Pavel

    2016-04-01

    The Central Asian Orogenic Belt (CAOB) in southern Mongolia consists of E-W trending Neoproterozoic cratons and Silurian-Devonian oceanic tectonic zones. Previous study revealed that the Early Paleozoic accretionary wedge and the oceanic tectonic zone are underlain by a layer giving a homogeneous gravity signal. Forward gravity modelling suggests that this layer is not formed of high-density material typical of lower oceanic crust but is composed of low- to intermediate-density rocks resembling continental crust. The nature of this lower crust is constrained by the whole-rock geochemistry and zircon Hf isotopic signature of abundant Late Carboniferous high-K calc-alkaline and Early Permian A-type granitoids intruding the two Early Paleozoic domains. It is possible to explain the genesis of these granitoids by anatexis of juvenile, metaigneous (tonalitic-gabbroic) rocks of Late Cambrian age, the source of which is presumed to lie in the "Khantaishir" arc (520-495Ma) further north. In order to test this hypothesis, the likely modal composition and density of Khantaishir arc-like protoliths are thermodynamically modelled at granulite- and higher amphibolite-facies conditions. It is shown that the current average density of the lower crust inferred by gravity modelling (2730 ±20kg/m3) matches best metamorphosed leucotonalite to diorite. Based on these results, it is now proposed that Mongolian CAOB has an architecture in which the accretionary wedge and oceanic upper crust is underlain by allochthonous lower crust that originated in a Cambrian arc. A tectonic model explaining relamination of allochthonous felsic to intermediate lower crust beneath mafic upper crust is proposed.

  16. Progression of natural attenuation processes at a crude-oil spill site . I. Geochemical evolution of the plume

    Science.gov (United States)

    Cozzarelli, I.M.; Bekins, B.A.; Baedecker, M.J.; Aiken, G.R.; Eganhouse, R.P.; Tuccillo, M.E.

    2001-01-01

    A 16-year study of a hydrocarbon plume shows that the extent of contaminant migration and compound-specific behavior have changed as redox reactions, most notably iron reduction, have progressed over time. Concentration changes at a small scale, determined from analysis of pore-water samples drained from aquifer cores, are compared with concentration changes at the plume scale, determined from analysis of water samples from an observation well network. The small-scale data show clearly that the hydrocarbon plume is growing slowly as sediment iron oxides are depleted. Contaminants, such as ortho-xylene that appeared not to be moving downgradient from the oil on the basis of observation well data, are migrating in thin layers as the aquifer evolves to methanogenic conditions. However, the plume-scale observation well data show that the downgradient extent of the Fe2+ and BTEX plume did not change between 1992 and 1995. Instead, depletion of the unstable Fe (III) oxides near the subsurface crude-oil source has caused the maximum dissolved iron concentration zone within the plume to spread at a rate of approximately 3 m/year. The zone of maximum concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) has also spread within the anoxic plume. In monitoring the remediation of hydrocarbon-contaminated ground water by natural attenuation, subtle concentration changes in observation well data from the anoxic zone may be diagnostic of depletion of the intrinsic electron-accepting capacity of the aquifer. Recognition of these subtle patterns may allow early prediction of growth of the hydrocarbon plume. Copyright ?? 2001 .

  17. Progression of natural attenuation processes at a crude-oil spill site. I. Geochemical evolution of the plume

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Bekins, Barbara A.; Baedecker, Mary Jo; Aiken, George R.; Eganhouse, Robert P.; Tuccillo, Mary Ellen

    2001-12-01

    A 16-year study of a hydrocarbon plume shows that the extent of contaminant migration and compound-specific behavior have changed as redox reactions, most notably iron reduction, have progressed over time. Concentration changes at a small scale, determined from analysis of pore-water samples drained from aquifer cores, are compared with concentration changes at the plume scale, determined from analysis of water samples from an observation well network. The small-scale data show clearly that the hydrocarbon plume is growing slowly as sediment iron oxides are depleted. Contaminants, such as ortho-xylene that appeared not to be moving downgradient from the oil on the basis of observation well data, are migrating in thin layers as the aquifer evolves to methanogenic conditions. However, the plume-scale observation well data show that the downgradient extent of the Fe 2+ and BTEX plume did not change between 1992 and 1995. Instead, depletion of the unstable Fe (III) oxides near the subsurface crude-oil source has caused the maximum dissolved iron concentration zone within the plume to spread at a rate of approximately 3 m/year. The zone of maximum concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) has also spread within the anoxic plume. In monitoring the remediation of hydrocarbon-contaminated ground water by natural attenuation, subtle concentration changes in observation well data from the anoxic zone may be diagnostic of depletion of the intrinsic electron-accepting capacity of the aquifer. Recognition of these subtle patterns may allow early prediction of growth of the hydrocarbon plume.

  18. Obtention of the cation exchange capacity of a natural kaolinite with radioactive tracers; Obtencion de la capacidad de intercambio cationico de una kaolinita natural con trazadores radioactivos

    Energy Technology Data Exchange (ETDEWEB)

    Uribe I, A.; Badillo A, V.E. [Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Monroy G, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: Adrya81@hotmail.com

    2005-07-01

    One of the more used techniques for the elimination of the heavy metals present in water systems is to use adsorbent mineral phases like zeolites and clays, among others. The clays are able to exchange easily the fixed ions in the external surface of its crystals or well the ions present in the interlaminar spaces of the structures, for other existent ones in the encircling aqueous solutions for that the Cation exchange capacity (CIC) is defined as the sum of all the cations exchange that a mineral can possess independent to the physicochemical conditions. The CIC is equal to the measure of the total of negative charges of the mineral by mass of the solid (meq/g). In this investigation work, the value of the CIC equal to 2.5 meq/100 g is obtained, of a natural kaolinite from the State of Hidalgo studying the retention of the sodium in the kaolinite with the aid of the radioactive isotope {sup 24} Na and of the selective electrodes technique, making vary the pH value. So is experimentally demonstrated that the CIC is an intrinsic property of the mineral independent of the pH value of the solution and of the charges origin. (Author)

  19. Application of 'BIPI' tests employing natural and artificial tracers in water flooded oil fields of the Neuquina Basin (Argentine)

    Energy Technology Data Exchange (ETDEWEB)

    Somaruga, C. [Comahue Univ., Engineering Dept., Neuquen (Argentina); Gazzera, C.; Wouterlood, C. [Petrolera Perez Companc SA. Area Entre Lomas., Neuquen (Argentina)

    2001-07-01

    A methodology to determine the origin and distribution of bottom water in an oil producing well influenced by several injectors in waterflooding projects is presented. This methodology is complementary of inter-well tracer tests and salinity records analysis and was denominated BIPI (brief interruptions of producing-injecting wells) test. It requires the closing of a well (injector or producer) during a short time and its later re-opening. The original flow pattern in the surroundings of the tested producing well is affected while the well is closed. So the water coming from a dominant injector can move forward invading areas of a layer that have been previously occupied by other waters. Once the well is re-opened, if there is a tracer concentration contrast between the waters, a concentration change is registered. The concentration change was measured and also its recurrence in waters produced during inter-well tracer tests and during waterflooding that are employing different injection water from the formation one. Also it was determined the original flow distribution in the surrounding of the producing well by means of a simple balance of tracer mass. It is presented and analyze here the results from tests that were performed in an oil field of the Neuquina Basin. They allowed to visualizing the current condition of the bottom water flow as well as to make predictions on future performance. (authors)

  20. A new aquifer assessment tool using reactive tracers

    Science.gov (United States)

    McKnight, D.; Smalley, A. L.; Banwart, S. A.; Lerner, D. N.; Thomson, N. R.; Thornton, S. F.; Wilson, R. D.

    2003-04-01

    A major obstacle to making informed decisions about trigger levels for restoration and choosing remediation options is that current Site Investigation (SI) practice fails to make optimal use of available SI techniques resulting in poor value for money in conceptual site models. Often it is simply too expensive to obtain the type of site data required to build the case for natural attenuation, even though this restoration option may be relatively cheaper than a pump-and-treat system. In particular, aquifer property measurement techniques for groundwater transport and reactions are too costly and this results in over-reliance on literature values or model assumptions. This results in overly uncertain predictions of in situ performance and therefore unnecessarily cautious risk assessment and costly remediation strategies. Therefore, cost-effective SI tools that have the capability of producing high quality characterisation data are required. The dipole flow test which circulates groundwater between isolated injection (source) and extraction (sink) chambers within a single borehole has been used successfully by others to delineate heterogeneous hydraulic properties in both highly permeable and fractured rock aquifers. We propose to extend this approach by adding a suite of reactive tracers into a dipole flow field to assess the geochemical properties and biodegradation potential of aquifers. If successful this will provide a method to ascertain site-specific parameters for use in appropriate reactive transport models. The initial phase of this project involves the construction of a laboratory-scale physical model of a dipole probe to investigate the utility of the dipole flow and reactive tracer test (DFRTT) as an aquifer assessment tool. This phase will also serve as the developmental stage between mathematical theory and a host of planned field trials. The development of the laboratory-scale DFRTT including initial scoping calculations, numerical simulation results

  1. National Geochemical Database: Soil

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of soil samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US...

  2. National Geochemical Database: Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment in...

  3. National Geochemical Database: Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment...

  4. Model to predict the flow of tracers in naturally fractured geothermal reservoirs; Modelo para predecir el flujo de trazadores en yacimientos geotermicos naturalmente fracturados

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Sabag, Jetzabeth

    1988-02-01

    The proposed model has been developed to study the flow of tracers through naturally fractured geothermal reservoirs. The idealized system of the reservoir is made up of two regions: A movable region, where diffusion and convection mechanisms are present and a stagnant or immovable region where the diffusion and adsorption mechanisms are considered: in both regions the loss of mass by radioactive decay is considered. The solutions of the basic flow equations are in the Laplace space and for its numerical inversion the Stehfest algorithm was used. In spite of the numerical dispersion that these solutions involve, a well defined tendency to infer the system behavior under different flow conditions was found. It was found that, for practical purposes, the size of the matrix blocks does not have an influence on the concentration response, and the solution is reduced to the one presented by Tang and associates. Under these conditions, the system behavior can be described by two non-dimensional parameters: The Peclet number in fractures, P{sub e1}, and a parameter. The tracer response for the peak solution was also derived. An analytical solution limit was found for the case in which {alpha} tends to zero, which corresponds to the case of a homogenous system. It was verified that this limit solution is valid, for {alpha}<0.01. For the case of continuous injection, this solution is reduced to the one presented by Coasts and Smith. For the peak solution, it was found that the irruption time corresponding to the maximum concentration is directly related to the non-dimensional group. Therefore, it is possible to obtain the value of P{sub e1} for a given X{sub D}, or vice versa. A group of graphs of non-dimensional concentration in the fracture versus non-dimensional time, was developed. It was found that if P{sub e1} remains constant whereas {alpha} changes, the limit solution is the envelope of a family of curves in a graph of C{sub D} versus t{sub D}. In this figure P

  5. Geochemical soil survey of the Netherlands. Atlas of major and trace elements in topsoil and parent material; assessment of natural and anthropegenic enrichment factors

    NARCIS (Netherlands)

    Veer, G. van der

    2006-01-01

    Geochemical surveying is a generic tool to provide high quality, multi-element databases of the Earth’s surface compartments such as soil, sediment, and stream water. Such databases are not only an essential component of environmental knowledge, but also of relevance to other fields such as spatial

  6. Packet Tracer network simulator

    CERN Document Server

    Jesin, A

    2014-01-01

    A practical, fast-paced guide that gives you all the information you need to successfully create networks and simulate them using Packet Tracer.Packet Tracer Network Simulator is aimed at students, instructors, and network administrators who wish to use this simulator to learn how to perform networking instead of investing in expensive, specialized hardware. This book assumes that you have a good amount of Cisco networking knowledge, and it will focus more on Packet Tracer rather than networking.

  7. TAPIR--Finnish national geochemical baseline database.

    Science.gov (United States)

    Jarva, Jaana; Tarvainen, Timo; Reinikainen, Jussi; Eklund, Mikael

    2010-09-15

    In Finland, a Government Decree on the Assessment of Soil Contamination and Remediation Needs has generated a need for reliable and readily accessible data on geochemical baseline concentrations in Finnish soils. According to the Decree, baseline concentrations, referring both to the natural geological background concentrations and the diffuse anthropogenic input of substances, shall be taken into account in the soil contamination assessment process. This baseline information is provided in a national geochemical baseline database, TAPIR, that is publicly available via the Internet. Geochemical provinces with elevated baseline concentrations were delineated to provide regional geochemical baseline values. The nationwide geochemical datasets were used to divide Finland into geochemical provinces. Several metals (Co, Cr, Cu, Ni, V, and Zn) showed anomalous concentrations in seven regions that were defined as metal provinces. Arsenic did not follow a similar distribution to any other elements, and four arsenic provinces were separately determined. Nationwide geochemical datasets were not available for some other important elements such as Cd and Pb. Although these elements are included in the TAPIR system, their distribution does not necessarily follow the ones pre-defined for metal and arsenic provinces. Regional geochemical baseline values, presented as upper limit of geochemical variation within the region, can be used as trigger values to assess potential soil contamination. Baseline values have also been used to determine upper and lower guideline values that must be taken into account as a tool in basic risk assessment. If regional geochemical baseline values are available, the national guideline values prescribed in the Decree based on ecological risks can be modified accordingly. The national geochemical baseline database provides scientifically sound, easily accessible and generally accepted information on the baseline values, and it can be used in various

  8. Geochemical Trends and Natural Attenuation of RDX, Nitrate, and Perchlorate in the Hazardous Test Area Fractured-Granite Aquifer, White Sands Missile Range, New Mexico, 1996-2006

    Science.gov (United States)

    Langman, Jeff B.; Robertson, Andrew J.; Bynum, Jamar; Gebhardt, Fredrick E.

    2008-01-01

    A fractured-granite aquifer at White Sands Missile Range is contaminated with the explosive compound RDX, nitrate, and perchlorate (oxidizer associated with rocket propellant) from the previous use of the Open Burn/Open Detonation site at the Hazardous Test Area. RDX, nitrate, and perchlorate ground-water concentrations were analyzed to examine source characteristics, spatial and temporal variability, and the influence of the natural attenuation processes of dilution and degradation in the Hazardous Test Area fractured-granite aquifer. Two transects of ground-water wells from the existing monitoring-site network - one perpendicular to ground-water flow (transect A-A') and another parallel to ground-water flow (transect B-B') - were selected to examine source characteristics and the spatial and temporal variability of the contaminant concentrations. Ground-water samples collected in 2005 from a larger sampling of monitoring sites than the two transects were analyzed for various tracers including major ions, trace elements, RDX degradates, dissolved gases, water isotopes, nitrate isotopes, and sulfate isotopes to examine the natural attenuation processes of dilution and degradation. Recharge entrains contaminants at the site and transports them downgradient towards the Tularosa Basin floor through a poorly connected fracture system(s). From 1996 to 2006, RDX, nitrate, and perchlorate concentrations in ground water downgradient from the Open Burn/Open Detonation site have been relatively stable. RDX, nitrate, and perchlorate in ground water from wells near the site indicate dispersed contaminant sources in and near the Open Burn/Open Detonation pits. The sources of RDX and nitrate in the pit area have shifted with time, and the shift correlates with the regrading of the south and east berms of each pit in 2002 and 2003 following closure of the site. The largest RDX concentrations were in ground water about 0.1 mile downgradient from the pits, the largest perchlorate

  9. The use of fluoride as a natural tracer in water and the relationship to geological features: Examples from the Animas River Watershed, San Juan Mountains, Silverton, Colorado

    Science.gov (United States)

    Bove, D.J.; Walton-Day, K.; Kimball, B.A.

    2009-01-01

    Investigations within the Silverton caldera, in southwestern Colorado, used a combination of traditional geological mapping, alteration-assemblage mapping, and aqueous geochemical sampling that showed a relationship between geological and hydrologic features that may be used to better understand the provenance and evolution of the water. Veins containing fluorite, huebnerite, and elevated molybdenum concentrations are temporally and perhaps genetically associated with the emplacement of high-silica rhyolite intrusions. Both the rhyolites and the fluorite-bearing veins produce waters containing elevated concentrations of F-, K and Be. The identification of water samples with elevated F/Cl molar ratios (> 10) has also aided in the location of water draining F-rich sources, even after these waters have been diluted substantially. These unique aqueous geochemical signatures can be used to relate water chemistry to key geological features and mineralized source areas. Two examples that illustrate this relationship are: (1) surface-water samples containing elevated F-concentrations (> 1.8 mg/l) that closely bracket the extent of several small high-silica rhyolite intrusions; and (2) water samples containing elevated concentrations of F-(> 1.8 mg/ l) that spatially relate to mines or areas that contain late-stage fluorite/huebnerite veins. In two additional cases, the existence of high F-concentrations in water can be used to: (1) infer interaction of the water with mine waste derived from systems known to contain the fluorite/huebnerite association; and (2) relate changes in water quality over time at a high elevation mine tunnel to plugging of a lower elevation mine tunnel and the subsequent rise of the water table into mineralized areas containing fluorite/huebnerite veining. Thus, the unique geochemical signature of the water produced from fluorite veins indicates the location of high-silica rhyolites, mines, and mine waste containing the veins. Existence of high F

  10. Rare earth elements (REE) as natural and applied tracers in the catchment area of Gessental valley, former uranium mining area of Eastern Thuringia, Germany

    Science.gov (United States)

    Buechel, G.; Merten, D.; Geletneky, J. W.; Kothe, E.

    2003-04-01

    Between 1947 and 1990 about 113.000 t of uranium were excavated at the former uranium mining site of Ronneburg (Eastern Thuringia, Germany). The legacy consists of more than 200 million m^3 of metasedimentary rocks rich in organic matter, sulfides and heavy metals originally deposited in mining heaps at the surface. The metasedimentary rocks formed under anoxic conditions about a 400 Mio. years ago are now exposed to oxic conditions. The oxidation of markasite and pyrite results in the formation of H_2SO_4. The formation of acid mine drainage (AMD) leads to high concentrations of uranium, rare earth elements (REE) and other heavy metals in surface water, seepage water and groundwater. This mobilization is due to alteration enhanced by high microbial activity and low pH. The tolerance mechanisms towards heavy metal pollution of soil substrate and surface/groundwater has allowed the selection of microbes which have, e.g. specific transporter genes and which are associated to plants in symbiotic interactions like mycorrhiza. In order to follow the processes linking alteration of metasedimentary rocks to biological systems the use of tracers is needed. One group of such tracers occuring in high concentrations in the water phase at the Ronneburg mining site are the REE (La-Lu) which are featured by very similar chemical behaviour. They show smooth but continuous variations of their chemical behaviour as a function of atomic number. For seepage water of the waste rock dump Nordhalde - sampled over a period of two years - the shale normalized REE patterns show enrichment of heavy REE and only minor variations, although the concentration differs. At sampling points in the surface water and in groundwater rather similar REE patterns were observed. Thus, REE can be used as tracers to identify diffuse inflow of REE-rich acid mine drainage of the dumps into the creek and the sediments. The absolute concentrations of REE in the creek and in ground water are up to 1000 times

  11. Geochemical processes between steel projectiles and silica-rich targets in hypervelocity impact experiments

    Science.gov (United States)

    Ebert, Matthias; Hecht, Lutz; Deutsch, Alexander; Kenkmann, Thomas; Wirth, Richard; Berndt, Jasper

    2014-05-01

    The possibility of fractionation processes between projectile and target matter is critical with regard to the classification of the impactor type from geochemical analysis of impactites from natural craters. Here we present results of five hypervelocity MEMIN impact experiments (Poelchau et al., 2013) using the Cr-V-Co-Mo-W-rich steel D290-1 as projectile and two different silica-rich lithologies (Seeberger sandstone and Taunus quartzite) as target materials. Our study is focused on geochemical target-projectile interaction occurring in highly shocked and projectile-rich ejecta fragments. In all of the investigated impact experiments, whether sandstone or quartzite targets, the ejecta fragments show (i) shock-metamorphic features e.g., planar-deformation features (PDF) and the formation of silica glasses, (ii) partially melting of projectile and target, and (iii) significant mechanical and chemical mixing of the target rock with projectile material. The silica-rich target melts are strongly enriched in the "projectile tracer elements" Cr, V, and Fe, but have just minor enrichments of Co, W, and Mo. Inter-element ratios of these tracer elements within the contaminated target melts differ strongly from the original ratios in the steel. The fractionation results from differences in the reactivity of the respective elements with oxygen during interaction of the metal melt with silicate melt. Our results indicate that the principles of projectile-target interaction and associated fractionation do not depend on impact energies (at least for the selected experimental conditions) and water-saturation of the target. Partitioning of projectile tracer elements into the silicate target melt is much more enhanced in experiments with a non-porous quartzite target compared with the porous sandstone target. This is mainly the result of higher impact pressures, consequently higher temperatures and longer reaction times at high temperatures in the experiments with quartzite as

  12. Tracer attenuation in groundwater

    Science.gov (United States)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  13. Tracer-based prediction of thermal reservoir lifetime: scope, limitations, and the role of thermosensitive tracers

    Science.gov (United States)

    Ghergut, I.; Behrens, H.; Karmakar, S.; Licha, T.; Nottebohm, M.; Sauter, M.

    2012-04-01

    correlation between (early) tracer signals and (later) thermal breakthrough can be re-established. Thus, thermosensitive tracers are indispensable for predicting thermal breakthrough, in such geothermal reservoirs whose 'hydrogeological personality' is given by a finite set of fractures, with flow occurring both across and along the fractures. In terms of the 'gebo benchmark-model' typology investigated by Hördt et al. (2011) [http://eposters.agu.org/abstracts/models-of-geothermal-reservoirs-as-a-basis-for-interdisciplinary-cooperation/] , such systems combine flow and transport patterns of the 'petrothermal' type and of the so-called 'deep-aquifer' type: across the fractures, heat is travelling faster than conservative-solute tracers; along the fractures, conservative-solute tracers experience much less retardation by transversal exchange (matrix diffusion), than heat; fluid (and tracer) flow is not limited to the fractures; matrix flow yields essential contribution to prolonging the fluid (and tracer) residence time. Thermal lifetime results from the opposite effects of fracture aperture as an: advection-related parameter: fluid travel time increases with increasing fracture aperture advection-unrelated parameter: fracture - matrix exchange rate increases with decreasing fracture aperture, which accelerates transport across the fracture, but retards transport along the fracture. In conservative-solute tracer signals, all these fracture aperture effects on tracer transport are masked by the very long residence time associated with the matrix flow component. Thermosensitive tracers are able to 'magnify' the visibility of fracture aperture effects against matrix flow effects. Acknowledgment: This study benefits from thermosensitive-tracer research conducted within the projects Smart Tracers and LOGRO, funded by the German Ministry for Environment, Nature Conservation and Nuclear Safety (BMU, 0327579 and 0325111B) and by Energie Baden-Württemberg (EnBW).

  14. A CRITICAL REVIEW AND EVALUATION OF APPLYING SEMI-VOLATILE ORGANIC COMPOUNDS (SVOCS AS A GEOCHEMICAL TRACER TO INDICATE TSUNAMI BACKWASH: The Bilateral, Deutsche Forschungsgemeinschaft (DFG and National Research Council of Thailand (NRCT Funded Project “Tsunami Deposits in Near-Shore- and Coastal Waters of Thailand (TUNWAT”

    Directory of Open Access Journals (Sweden)

    Siwatt Pongpiachan

    2013-10-01

    Full Text Available Tsunamis symbolize one of the most harmful natural disasters for low-lying coastal zones and their residents, due to both its destructive power and irregularity. The 2004 Boxing Day tsunami, which attack the Andaman Sea coast of Thailand, resulted 5,395 of deaths and inestimable casualties, interrupted economies and social well-being in numerous coastal villages and caused in extreme alterations of both onshore and offshore coastal morphology. The Great Indian Ocean tsunami also highlighted that there are many missing jigsaw puzzle pieces in scientific knowledge, starting from the generating of tsunamis offshore to the countless influences to the marine ecosystems on the continental shelf, coastal areas and on land and to the economic and social systems consequences. As with all deposits that do not have a direct physical link to their causative sources, marine tsunami deposits must be distinguished from other deposits through regional correlation, dating and criteria for recognition within the deposits themselves. This study aims to provide comprehensive reviews on using Polycyclic Aromatic Hydrocarbons (PAHs as a chemical proxy to discriminate tsunami relateddeposits from typical marine sediments. The advantages and disadvantages of this chemical tracer will be critically reviewed and further discussed.

  15. Composition of natural gas and crude oil produced from 10 wells in the Lower Silurian "Clinton" Sandstone, Trumbull County, Ohio: Chapter G.7 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Burruss, Robert A.; Ryder, Robert T.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    Natural gases and associated crude oils in the “Clinton” sandstone, Medina Group sandstones, and equivalent Tuscarora Sandstone in the northern Appalachian basin are part of a regional, continuous-type or basin-centered accumulation. The origin of the hydrocarbon charge to regional continuoustype accumulations is poorly understood. We have analyzed the molecular and stable isotopic composition of gases and oils produced from 10 wells in the “Clinton” sandstone in Trumbull County, Ohio, in an initial attempt to identify the characteristics of the accumulated fluids. The analyses show that the fluids have remarkably uniform compositions that are similar to previously published analyses of oils (Cole and others, 1987) and gases (Laughrey and Baldasarre, 1998) in Early Silurian reservoirs elsewhere in Ohio; however, geochemical parameters in the oils and gases suggest that the fluids have experienced higher levels of thermal stress than the present-day burial conditions of the reservoir rocks. The crude oils have an unusual geochemical characteristic: they do not contain detectable levels of sterane and triterpane biomarkers. The origin of these absences is unknown.

  16. Composition of natural gas and crude oil produced from 10 wells in the Lower Silurian "Clinton" Sandstone, Trumbull County, Ohio: Chapter G.7 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Burruss, Robert A.; Ryder, Robert T.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    Natural gases and associated crude oils in the “Clinton” sandstone, Medina Group sandstones, and equivalent Tuscarora Sandstone in the northern Appalachian basin are part of a regional, continuous-type or basin-centered accumulation. The origin of the hydrocarbon charge to regional continuoustype accumulations is poorly understood. We have analyzed the molecular and stable isotopic composition of gases and oils produced from 10 wells in the “Clinton” sandstone in Trumbull County, Ohio, in an initial attempt to identify the characteristics of the accumulated fluids. The analyses show that the fluids have remarkably uniform compositions that are similar to previously published analyses of oils (Cole and others, 1987) and gases (Laughrey and Baldasarre, 1998) in Early Silurian reservoirs elsewhere in Ohio; however, geochemical parameters in the oils and gases suggest that the fluids have experienced higher levels of thermal stress than the present-day burial conditions of the reservoir rocks. The crude oils have an unusual geochemical characteristic: they do not contain detectable levels of sterane and triterpane biomarkers. The origin of these absences is unknown.

  17. A review of biomarker compounds as source indicators and tracers for air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States). Environmental and Petroleum Geochemistry Group

    1999-07-01

    An overview of the application of organic geochemistry to the analysis of organic matter on aerosol particles is presented here. This organic matter is analyzed as solvent extractable bitumen/lipids by gas chromatography-mass spectrometry. The organic geochemical approach assesses the origin, the environmental history and the nature of secondary products of organic matter by using the data derived from specific molecular analyses. Evaluations of production and fluxes, with cross-correlations can thus be made by the application of the same separation and analytical procedures to samples form point source emissions and the ambient atmosphere. This will be illustrated here with typical examples from the ambient atmosphere (aerosol particles) and from emissions of biomass burning (smoke). Organic matter in aerosols is derived from two major sources and is admixed depending on the geographic relief of the air shed. These sources are biogenic detritus (e.g., plant wax, microbes, etc.) and anthropogenic particle emissions (e.g., oils, soot, synthetics, etc.). Both biogenic detritus and some of the anthropogenic particle emissions contain organic materials which have unique and distinguishable compound distribution patterns (C{sub 14}-C{sub 40}). Microbial and vascular plant lipids are the dominant biogenic residues and petroleum hydrocarbons, with lesser amounts of the pyrogenic polynuclear aromatic hydrocarbons (PAH) and synthetics (e.g., chlorinated compounds), are the major anthropogenic residues. Biomass combustion is another important primary source of particles injected into the global atmosphere. It contributes many trace substances which are reactants in atmospheric chemistry and soot particulate matter with adsorbed biomarker compounds, most of which are unknown chemical structures. The injection of natural product organic compounds into smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature

  18. Characterizing the Influence of Flow Regime and Landcover on the Geochemical Nature and Magnitude of Riverine Phosphorus and Trace Metal Loads

    Science.gov (United States)

    Rosenberg, B.; Schroth, A. W.

    2014-12-01

    Within aquatic systems, phosphorus (P) is a common limiting nutrient present in low bioavailable concentrations. Colloidal and particulate phases of the trace metals manganese (Mn) and iron (Fe) are common scavengers of phosphate in the freshwater environment, and the distribution and stability of such phases is thought to influence the bioavailability of P. The partitioning and flux of P and TM in rivers can be driven by the geochemical source of these constituents, as well as the hydrologic/biogeochemical pathways active within the watershed, both of which vary based on hydrologic condition and landcover. This study investigates how different landcovers (suburban, agricultural, forested, glacial) contribute to P and TM flux and partitioning during high-flow events (snowmelt, glacial melt, storms). High-resolution water and suspended sediment sampling was conducted during snowmelt in Vermont, as well as during summer storms and baseflow conditions. In Alaska, samples were collected during baseflow, glacial melt, and storm events to provide additional data from other landcovers and hydrologic systems. Initial analyses suggest that the size fraction, loading, and relative lability of water and suspended sediment pools of TM and P are strongly influenced by both land cover and seasonality/hydrology. Samples collected during snowmelt in VT show high concentrations of dissolved and potentially bioavailable particulate P at the start of melt that decrease over time. Coupled with high discharge events, a substantial load of labile P is delivered during this particular high flow period. As snowmelt transitions to baseflow conditions, with intermittent storms the character of the suspended sediment changes drastically, with lower total concentrations of P and TM as well as a lower proportion of extractable P (bound to easily reduced oxyhydroxides) to total sediment P. This study highlights that the snowmelt period is not only important from an overall all load standpoint

  19. National Geochemical Database: Concentrate

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemistry of concentrates from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are from the continental US and...

  20. Geochemical and Isotopic (Sr, U) Tracing of Weathering Processes Controlling the Recent Geochemical Evolution of Soil Solutions in the Strengbach Catchment (Vosges, France)

    Science.gov (United States)

    Chabaux, F. J.; Prunier, J.; Pierret, M.; Stille, P.

    2012-12-01

    The characterization of the present-day weathering processes controlling the chemical composition of waters and soils in natural ecosystems is an important issue to predict and to model the response of ecosystems to recent environmental changes. It is proposed here to highlight the interest of a multi-tracer geochemical approach combining measurement of major and trace element concentrations along with U and Sr isotopic ratios to progress in this topic. This approach has been applied to the small granitic Strengbah Catchment, located in the Vosges Mountain (France), used and equipped as a hydro-geochemical observatory since 1986 (Observatoire Hydro-Géochimique de l'Environnement; http://ohge.u-strasbg.fr). This study includes the analysis of major and trace element concentrations and (U-Sr) isotope ratios in soil solutions collected within two soil profiles located on two experimental plots of this watershed, as well as the analysis of soil samples and vegetation samples from these two plots The depth variation of elemental concentration of soil solutions confirms the important influence of the vegetation cycling on the budget of Ca, K, Rb and Sr, whereas Mg and Si budget in soil solutions are quasi exclusively controlled by weathering processes. Variation of Sr, and U isotopic ratios with depth also demonstrates that the sources and biogeochemical processes controlling the Sr budget of soil solutions is different in the uppermost soil horizons and in the deeper ones, and clearly influence by the vegetation cycling.

  1. Protein retention assessment of four levels of poultry by-product substitution of fishmeal in rainbow trout (Oncorhynchus mykiss diets using stable isotopes of nitrogen (δ15N as natural tracers.

    Directory of Open Access Journals (Sweden)

    Daniel Badillo

    Full Text Available This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM compared to fishmeal (FM was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (δ(15N values as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources.

  2. Geochemical quantification of semiarid mountain recharge.

    Science.gov (United States)

    Wahi, Arun K; Hogan, James F; Ekwurzel, Brenda; Baillie, Matthew N; Eastoe, Christopher J

    2008-01-01

    Analysis of a typical semiarid mountain system recharge (MSR) setting demonstrates that geochemical tracers help resolve the location, rate, and seasonality of recharge as well as ground water flowpaths and residence times. MSR is defined as the recharge at the mountain front that dominates many semiarid basins plus the often-overlooked recharge through the mountain block that may be a significant ground water resource; thus, geochemical measurements that integrate signals from all flowpaths are advantageous. Ground water fluxes determined from carbon-14 ((14)C) age gradients imply MSR rates between 2 x 10(6) and 9 x 10(6) m(3)/year in the Upper San Pedro Basin, Arizona, USA. This estimated range is within an order of magnitude of, but lower than, prior independent estimates. Stable isotopic signatures indicate that MSR has a 65% +/- 25% contribution from winter precipitation and a 35% +/- 25% contribution from summer precipitation. Chloride and stable isotope results confirm that transpiration is the dominant component of evapotranspiration (ET) in the basin with typical loss of more than 90% of precipitation-less runoff to ET. Such geochemical constraints can be used to further refine hydrogeologic models in similar high-elevation relief basins and can provide practical first estimates of MSR rates for basins lacking extensive prior hydrogeologic measurements.

  3. Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

    Science.gov (United States)

    Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

    2015-12-01

    Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

  4. Studying uranium migration in natural environment: experimental approach and geochemical modeling; Etude de la migration de l'uranium en milieu naturel: approche experimentale et modelisation geochimique

    Energy Technology Data Exchange (ETDEWEB)

    Phrommavanh, V.

    2008-10-15

    The present study deals with characterizing uranium migration in a limited zone of Le Bouchet site, a former uranium ore treatment facility, which is dismantled and the rehabilitation of which is under process. Some wastes are packed in a rehabilitated disposal nearby, called the Itteville site. In the framework of the monitoring of the deposit environment (air, water, sediment) set by prefectorial decrees, a piezometer (PZPK) located downstream to the latter, has shown total dissolved uranium peaks each winter since the 1990's. PZPK collects both the interstitial water of a calcareous peat formation, between the surface and 3 m, and an alluvial aquifer near 6 m of depth. Firstly, a hydrogeochemical characterization of the site has evidenced the uranium source term, which is present in the peat soil near 0.8 m, hence excluding any leaching from the waste disposal. Actually, a few microparticles of uranium oxide and mixed uranium-thorium oxide have been detected, but they do not represent the major part of the source term. Secondly, water chemistry of the peat soil water and PZPK has been monitored every two months from 2004 to 2007 in order to understand the reasons of the seasonal fluctuations of [U]tot.diss.. Completed with geochemical modeling and a bacterial identification by 16S rDNA sequence analysis, water chemistry data showed an important sulfate-reducing bacterial activity in summertime, leading to reducing conditions and therefore, a total dissolved uranium content limited by the low solubility of uraninite U{sup IV}O{sub 2}(s). In wintertime, the latter bacterial activity being minimal and the effective pluviometry more important, conditions are more oxidant, which favors U(VI), more soluble, notably as the Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) complex, evidenced by TRLFS. Finally, bacterial activity has been reproduced in laboratory in order to better characterize its impact on uranium solubility in the peat soil. Various parameters were tested

  5. Acid drainage at the inactive Santa Lucia mine, western Cuba: Natural attenuation of arsenic, barium and lead, and geochemical behavior of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Francisco Martin, E-mail: fmrch@geologia.unam.mx [Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Delegacion Coyoacan, 04510 Mexico D.F. (Mexico); Prol-Ledesma, Rosa Maria; Canet, Carles [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Delegacion Coyoacan, 04510 Mexico D.F. (Mexico); Alvares, Laura Nunez; Perez-Vazquez, Ramon [Facultad de Geologia y Mecanica, Universidad de Pinar del Rio (Cuba)

    2010-05-15

    A detailed geochemical study was conducted at the inactive Zn-Pb mine of Santa Lucia, in western Cuba. The studied mine-wastes are characterized by high total concentrations of potentially toxic elements (PTE), with average values of 17.4% Fe, 5.47% Ba, 2.27% Pb, 0.83% Zn, 1724 mg/kg As and 811 mg/kg Cu. Oxidation of sulfide minerals in mine-waste dumps and in the open pit produces acid mine effluents (pH = 2.5-2.6) enriched in dissolved SO{sub 4}{sup 2-} (up to 6754 mg/L), Fe (up to 4620 mg/L) and Zn (up to 2090 mg/L). Low pH values (2.5-2.8) and high dissolved concentrations of the same PTE were found in surface waters, up to 1500 m downstream from the mine. Nevertheless, concentrations of As, Ba and Pb in acid mine effluents and impacted surface waters are relatively low: 0.01-0.3 mg/L As, 0.002-0.03 mg/L Ba and 0.3-4.3 mg/L Pb. Analysis by X-ray diffraction and electron microscopy revealed the occurrence of lead-bearing barite and beudantite and the more common solid phases, reported elsewhere in similar environments including Fe-oxyhydroxides, jarosite, anglesite and plumbojarosite. Because the reported solubilities for barite and beudantite are very low under acidic conditions, these minerals may serve as the most important control in the mobility of As, Ba and Pb. In contrast, Fe-oxyhydroxides are relatively soluble under acidic conditions and, therefore, they may have a less significant role in PTE on-site immobilization. Mine-wastes and stream sediments show a light REE (LREE) and middle REE (MREE) enrichment relative to heavy REE (HREE). In contrast, acid mine effluents and surface waters are enriched in HREE relative to LREE. These results suggest that the LREE released during the oxidation of sulfides are captured by secondary (weathering) minerals, while the MREE are removed from the altered rocks. The low concentrations of LREE in acid stream water suggest that these elements can be retained in the sediments more strongly than HREE and MREE. One

  6. Toxicity of fluorescent tracers and their degradation byproducts

    Directory of Open Access Journals (Sweden)

    Philippe Gombert

    2017-01-01

    Full Text Available Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

  7. Journal: Efficient Hydrologic Tracer-Test Design for Tracer ...

    Science.gov (United States)

    Hydrological tracer testing is the most reliable diagnostic technique available for the determination of basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed to facilitate the design of tracer tests by root determination of the one-dimensional advection-dispersion equation (ADE) using a preset average tracer concentration which provides a theoretical basis for an estimate of necessary tracer mass. The method uses basic measured field parameters (e.g., discharge, distance, cross-sectional area) that are combined in functional relatipnships that descrive solute-transport processes related to flow velocity and time of travel. These initial estimates for time of travel and velocity are then applied to a hypothetical continuous stirred tank reactor (CSTR) as an analog for the hydrological-flow system to develop initial estimates for tracer concentration, tracer mass, and axial dispersion. Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be necessary for descri

  8. Tracer tomography (in) rocks!

    Science.gov (United States)

    Somogyvári, Márk; Jalali, Mohammadreza; Jimenez Parras, Santos; Bayer, Peter

    2016-04-01

    Physical behavior of fractured aquifers is rigorously controlled by the presence of interconnected conductive fractures, as they represent the main pathways for flow and transport. Ideally, they are simulated as a discrete fracture network (DFN) in a model to capture the role of fracture system geometry, i.e. fracture length, height, and width (aperture/transmissivity). Such network may be constrained by prior geological information or direct data resources such as field mapping, borehole logging and geophysics. With the many geometric features, however, calibration of a DFN to measured data is challenging. This is especially the case when spatial properties of a fracture network need to be calibrated to flow and transport data. One way to increase the insight in a fractured rock is by combining the information from multiple field tests. In this study, a tomographic configuration that combines multiple tracer tests is suggested. These tests are conducted from a borehole with different injection levels that act as sources. In a downgradient borehole, the tracer is recorded at different levels or receivers, in order to maximize insight in the spatial heterogeneity of the rock. As tracer here we chose heat, and temperature breakthrough curves are recorded. The recorded tracer data is inverted using a novel stochastic trans-dimensional Markov Chain Monte Carlo procedure. An initial DFN solution is generated and sequentially modified given available geological information, such as expected fracture density, orientation, length distribution, spacing and persistency. During this sequential modification, the DFN evolves in a trans-dimensional inversion space through adding and/or deleting fracture segments. This stochastic inversion algorithm requires a large number of thousands of model runs to converge, and thus using a fast and robust forward model is essential to keep the calculation efficient. To reach this goal, an upwind coupled finite difference method is employed

  9. Geochemical modelling of the weathering zone of the 'Mina Fe' U deposit (Spain): A natural analogue for nuclear spent fuel alteration and stability processes in radwaste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Arcos, D. [AMPHOS XXI Consulting S.L., Passeig de Rubi, 29-31, 08197 Valldoreix, Barcelona (Spain)], E-mail: david.arcos@amphos21.com; Perez del Villar, L. [CIEMAT, Dpto.de Medio Ambiente, Avda, Complutense 22, 28040 Madrid (Spain); Bruno, J.; Domenech, C. [AMPHOS XXI Consulting S.L., Passeig de Rubi, 29-31, 08197 Valldoreix, Barcelona (Spain)

    2008-04-15

    The 'Mina Fe' U deposit (Salamanca, Spain) has been studied in the context of Enresa's programme for U-mine sites restoration and also as a natural analogue for processes in high-level nuclear waste (HLNW) geological disposal. The investigations encompassed an array of geoscience disciplines, such as structural geology, mineralogy, hydrogeology and elemental and isotopic geochemistry and hydrogeochemistry of the site. Based on the obtained results, a conceptual mineralogical and geochemical model was performed integrating the main geochemical processes occurring at the site: the interaction between oxidised and slightly acidic water with pyrite, pitchblende, calcite and dolomite, as essential minerals of the U fracture-filling mineralisation, and hydroxyapatite from the host rock, as the main source of P. This conceptual model has been tested in a systematic numerical model, which includes the main kinetic (pyrite and pitchblende dissolution) and equilibrium processes (carbonate mineral dissolution, and goethite, schoepite and autunite secondary precipitation). The results obtained from the reactive-transport model satisfactorily agree with the conceptual model previously established. The assumption of the precipitation of coffinite as a secondary mineral in the system cannot be correctly evaluated due to the lack of hydrochemical data from the reducing zone of the site and valid thermodynamic and kinetic data for this hydrated U(IV)-silicate. This precipitation can also be hampered by the probable existence of dissolved U(IV)-organic matter and/or uranyl carbonate complexes, which are thermodynamically stable under the alkaline and reducing conditions that prevail in the reducing zone of the system. Finally, the intense downwards oxic and acidic alteration in the upper part of the system is of no relevance for the performance assessment of a HLNW disposal. However, the acidic and oxidised conditions are quickly buffered to neutral-alkaline and

  10. Geochemical Calculations Using Spreadsheets.

    Science.gov (United States)

    Dutch, Steven Ian

    1991-01-01

    Spreadsheets are well suited to many geochemical calculations, especially those that are highly repetitive. Some of the kinds of problems that can be conveniently solved with spreadsheets include elemental abundance calculations, equilibrium abundances in nuclear decay chains, and isochron calculations. (Author/PR)

  11. A multi-tracer approach for the exploration of deep geothermal energy potential and fault zone characterisation, applied in the Upper Rhine Graben

    Science.gov (United States)

    Freundt, Florian; Najem, Sami Al; Aeschbach-Hertig, Werner; Isenbeck-Schröter, Margot; Schmidt, Gerhard; Grobe, René; Kraml, Michael

    2014-05-01

    Current methods of geothermal exploration rely on various expensive geophysical methods (e.g. 3D reflection seismics) to identify permeable fault zones and the geometry of geothermal aquifers. However this analysis alone does not allow for an estimation of an active fault's hydraulic permeability nor provides a characterisation of the chemical properties of the deep aquifer fluid. Both factors play an important role in optimising siting of geothermal wells and operation of a geothermal power plant. This work presents a low cost strategy characterizing deep hydrogeochemical reservoirs using a combination of methods from hydrogeochemistry and isotope hydrology in hot springs and near surface groundwater. The main goal is to confine the area of interest for further, indirect geophysical investigation. For this purpose natural geochemical and isotopical tracers as well as rare earth elements, 3He/4He ratios, and radiogenic isotopes (Sr and Pb) are investigated. Data from the first sampling campaign in the northern Upper Rhine Graben, close to Groß-Gerau, Germany, shows promising results, indicating an area of increased interest where elevated helium ratios coincide with characteristic geochemical data, fault location and a previously known saltwater anomaly. Geochemical analyses exhibit three different types of fluids and various mixtures. CaHCO3-dominated waters represent Quaternary aquifer conditions whereas MgSO4-dominated waters are characterised by a Tertiary aquifer rock. Higher saline NaCl-dominated waters show an impact of mantle fluids revealed by 3He/4He isotope analysis. The ratio is highest where the main fault of the northern Upper Rhine Graben crosses the Rhine river. This suggests that the fault is hydraulically active and connects ascending deep fluids with the shallow aquifer. Further investigations of rare earth element patterns as well as radiogenic isotopes will identify the origin, the ascent as well as the retention time of the deep fluids more

  12. Development of radioisotope tracer technology

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Joon Ha; Lee, Myun Joo; Jung, Sung Hee; Park, Soon Chul; Lim, Dong Soon; Kim, Jae Ho; Lee, Jae Choon; Lee, Doo Sung; Cho, Yong Suk; Shin, Sung Kuan

    2000-04-01

    The purpose of this study is to develop the radioisotope tracer technology, which can be used in solving industrial and environmental problems and to build a strong tracer group to support the local industries. In relation to the tracer technology in 1999, experiments to estimate the efficiencies of a sludge digester of a waste water treatment plant and a submerged biological reactor of a dye industry were conducted. As a result, the tracer technology for optimization of facilities related to wastewater treatment has been developed and is believed to contribute to improve their operation efficiency. The quantification of the experimental result was attempted to improve the confidence of tracer technology by ECRIN program which basically uses the MCNP simulation principle. Using thin layer activation technique, wear of tappet shim was estimated. Thin layer surface of a tappet shim was irradiated by proton beam and the correlation between the measured activity loss and the amount of wear was established. The equipment was developed to adjust the energy of proton which collides with the surface of tappet. The tracer project team has participated into the tracer test for estimating the efficiency of RFCC system in SK cooperation. From the experiment the tracer team has obtained the primary elements to be considered for judging the efficiency of RFCC unit. By developing the tracer techniques to test huge industrial units like RFCC, the tracer team will be able to support the local industries that require technical services to solve any urgent trouble. (author)

  13. Regional Geochemical Division-A Tool for Delineating Geochemical Block

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Regional geochemical division is a mapping technique to divide an area into slices where the associations between geochemical elements are relatively simple and uniform. The result of division is expressed on a 2-D map. The scheme of regional geochemical division includes non-supervised pattern recognition, elementary statistics and factor analysis. A practical example in a gold prospecting area in Jilin, China, and the corresponding explanation are presented. Regional geochemical division is a basic approach to the delineation of the geochemical blocks as well.

  14. Nanoparticle tracers in calcium carbonate porous media

    KAUST Repository

    Li, Yan Vivian

    2014-07-15

    Tracers are perhaps the most direct way of diagnosing subsurface fluid flow pathways for ground water decontamination and for natural gas and oil production. Nanoparticle tracers could be particularly effective because they do not diffuse away from the fractures or channels where flow occurs and thus take much less time to travel between two points. In combination with a chemical tracer they can measure the degree of flow concentration. A prerequisite for tracer applications is that the particles are not retained in the porous media as the result of aggregation or sticking to mineral surfaces. By screening eight nanoparticles (3-100 nm in diameter) for retention when passed through calcium carbonate packed laboratory columns in artificial oil field brine solutions of variable ionic strength we show that the nanoparticles with the least retention are 3 nm in diameter, nearly uncharged, and decorated with highly hydrophilic polymeric ligands. The details of these column experiments and the tri-modal distribution of zeta potential of the calcite sand particles in the brine used in our tests suggests that parts of the calcite surface have positive zeta potential and the retention of negatively charged nanoparticles occurs at these sites. Only neutral nanoparticles are immune to at least some retention. © 2014 Springer Science+Business Media.

  15. Isotopic evidence for the retention of Sr-90 inferred from excess Zr-90 in the Oklo natural fission reactors: Implication for geochemical behaviour of fissiogenic Rb, Sr, Cs and Ba

    Science.gov (United States)

    Hidaka, Hiroshi; Sugiyama, Takeshi; Ebihara, Mitsuru; Holliger, Philippe

    1994-03-01

    In order to investigate the mobility of fissiogenic Sr-90 in the geological environment, the Zr isotopic compositions of seven samples from one of the newly formed Oklo natural reactor zones (i.e., reactor core and adjacent rocks (10, SF84)) in the Republic of Gabon were determined with an inductively coupled plasma mass spectrometer (ICP-MS). Zr isotopes in uraninite grains from different reactor zones were also measured by secondary ion mass spectrometry (SIMS). Fissiogenic Zr isotopic abundances of three samples from the reactor core have excess Zr-90, which has never before been formed in previous Oklo samples. In this paper, the geochemical behaviour of Zr-90 is discussed by making use of the relative retentivity inferred from the isotopic abundance of Sr. The excess in Zr-90 suggests dependence on the degree of retention/migration of Sr-90, the precursor of Zr-90 in the fission chain. In the aqueous phase, chemical fractionation between Sr and Zr could have occurred before radioactive Sr-90 decayed. Considering the halflife of Sr-90 (t(sub 1/2) = 29.1 y), considerable amounts of the latter have been produced during criticality. Sr and Zr (including Zr-90) could have been redistributed between the reactor core and its vicinity. The retentivity of fissiogenic Zr-90 in reactor core 10 is not homogeneous. In addition, the distributions of Rb, Cs and Ba is also heterogeneous.

  16. Iodine and selenium in natural water, their fixation on geochemical barriers in soils and rocks and explanation of I and Se behavior in water-solid phase system using thermodynamic modeling

    Science.gov (United States)

    Korobova, Elena; Ryzhenko, Boris; Cherkasova, Elena; Sedykh, Ivelina; Korsakova, Nadezhda; Berezkin, Victor; Kolmykova, Lyudmila; Danilova, Valentina; Khushvakhtova, Sabzbakhor

    2014-05-01

    Iodine and selenium are essential for normal functioning of thyroid gland. Their natural deficiency in areas subjected to radioiodine contamination during nuclear tests and accidents may increase the risk of thyroid cancer among the most sensitive groups of population. Deficiency is caused by both the low abundance of microelements in the environmental components of the local food chain and their fixation on geochemical barriers due to such processes as chemical transformation, sorption, chemisorption, complexing. The studies of iodine and selenium distribution in soils, herbs and drinking water in rural settlements of the Bryansk oblast' confirmed low level of iodine and selenium content in local soils, plants and water and revealed different character of their distribution in soils and waters formed in geochemically different conditions of water migration in areas of fluvioglacial, moraine and loess-like soil forming rocks (the polesje, moraine and opolje landscapes correspondingly). Iodine content in top horizons of the soils developed on loess-like sediments and rich in organic matter was considerably higher as compared to those formed on sandy moraine or fluvioglacial sediments. For selenium the difference was not pronounced. Iodine was noted for positive correlation with Corg and fixation in the soil profile on carbonate barrier. A negative correlation was found between selenium content in grasses and in topsoil of subordinated elementary landscapes characterized by waterlogged and reduction conditions in soils. Thermodynamic modeling performed for 47 water samples on the basis of their chemical composition helped to explain the established patterns of iodine and selenium behavior in soil-water system. It demonstrated the possibility of existence of CaI+ and MgI+ complexes in water and sedimentation of FeSe(cr) in presence of a considerable amount of Fe2+. Iodine complexation with Ca and Mg ions may explain its further fixation on carbonate barrier in soils

  17. Geochemical and isotopic evidences from groundwater and surface water for understanding of natural contamination in chronic kidney disease of unknown etiology (CKDu) endemic zones in Sri Lanka.

    Science.gov (United States)

    Edirisinghe, E A N V; Manthrithilake, H; Pitawala, H M T G A; Dharmagunawardhane, H A; Wijayawardane, R L

    2017-09-26

    Chronic kidney disease of unknown etiology (CKDu) is the main health issue in the dry zone of Sri Lanka. Despite many studies carried out, causative factors have not been identified yet clearly. According to the multidisciplinary researches carried out so far, potable water is considered as the main causative factor for CKDu. Hence, the present study was carried out with combined isotopic and chemical methods to understand possible relationships between groundwater; the main drinking water source, and CKDu in four endemic areas in the dry zone. Different water sources were evaluated isotopically ((2)H, (3)H and (18)O) and chemically from 2013 to 2015. Results revealed that prevalence of CKDu is significantly low with the groundwater replenished by surface water inputs. It is significantly high with the groundwater stagnated as well as groundwater recharged from regional flow paths. Thus, the origin, recharge mechanism and flow pattern of groundwater, as well as geological conditions which would be responsible for natural contamination of groundwater appear as the main causative factors for CKDu. Therefore, detailed investigations should be made in order to identify the element(s) in groundwater contributing to CKDu. The study recommends providing drinking water to the affected zones using water sources associated with surface waters.

  18. Characterization of an alluvial aquifer with thermal tracer tomography

    Science.gov (United States)

    Somogyvári, Márk; Bayer, Peter

    2017-04-01

    In the summer of 2015, a series of thermal tracer tests was performed at the Widen field site in northeast Switzerland. At this site numerous hydraulic, tracer, geophysical and hydrogeophysical field tests have been conducted in the past to investigate a shallow alluvial aquifer. The goals of the campaign in 2015 were to design a cost-effective thermal tracer tomography setup and to validate the concept of travel time-based thermal tracer tomography under field conditions. Thermal tracer tomography uses repeated thermal tracer injections with different injection depths and distributed temperature measurements to map the hydraulic conductivity distribution of a heterogeneous aquifer. The tracer application was designed with minimal experimental time and cost. Water was heated in inflatable swimming pools using direct sunlight of the warm summer days, and it was injected as low temperature pulses in a well. Because of the small amount of injected heat, no long recovery times were required between the repeated heat tracer injections and every test started from natural thermal conditions. At Widen, four thermal tracer tests were performed during a period of three days. Temperatures were measured in one downgradient well using a distributed temperature measurement system installed at seven depth points. Totally 12 temperature breakthrough curves were collected. Travel time based tomographic inversion assumes that thermal transport is dominated by advection and the travel time of the thermal tracer can be related to the hydraulic conductivities of the aquifer. This assumption is valid in many shallow porous aquifers where the groundwater flow is fast. In our application, the travel time problem was treated by a tomographic solver, analogous to seismic tomography, to derive the hydraulic conductivity distribution. At the test site, a two-dimensional cross-well hydraulic conductivity profile was reconstructed with the travel time based inversion. The reconstructed profile

  19. Geochemical modeling: a review

    Energy Technology Data Exchange (ETDEWEB)

    Jenne, E.A.

    1981-06-01

    Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

  20. Polonium-210 and lead-210 in the Southern Polar Ocean: Naturally occurring tracers of biological and hydrographical processes in the surface waters of the Antarctic Circumpolar Current and the Weddell Sea; Polonium-210 und Blei-210 im Suedpolarmeer: Natuerliche Tracer fuer biologische und hydrographische Prozesse im Oberflaechenwasser des Antarktischen Zirkumpolarstroms und des Weddellmeeres

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, J.

    1997-11-01

    In this thesis the distribution of {sup 210}Po and {sup 210}Pb in the upper 600 m of the Antarctic Circumpolar Current and the Weddell Sea was investigated along north-south transects in austral spring and autumn. {sup 210}Po and {sup 210}Pb can serve as sensitive tracers for the special hydrographic conditions of the Antarctic Circumpolar Current and the Weddell Sea as well as for biological processes during phytoplankton blooms. The {sup 210}Po/{sup 210}Pb disequilibrium was used as a tracer for particle export. This tracer integrates export on a timescale of 276 days because of the 138 day half-life of {sup 210}Po and complements the {sup 234}Th/{sup 238}U disequilibrium as another tracer for plankton production and export on a shorter timescale of several weeks. (orig.) [Deutsch] In der vorliegenden Arbeit wurde die Verteilung von Blei-210 und seinem Enkelnuklid Polonium-210 im Antarktischen Zirkumpolarstrom und im Weddellmeer bis 600 m Tiefe in mehreren meridionalen Transekten im australen Fruehjahr und Herbst waehrend der `Polarstern`-Expeditionen ANT-X/6 und ANT-XI/4 untersucht. Die Verteilung von {sup 210}Pb und {sup 210}Po wird von mehreren Faktoren beeinflusst, sowohl durch die Advektion von Wassermassen im Antarktischen Zirkumpolarstrom und im Weddellmeer als auch von biologischen Prozessen z.B. innerhalb einer Planktonbluete. Bevor die Verteilungsmuster von {sup 210}Pb und {sup 210}Po jedoch als Tracer fuer einen Prozess genutzt werden koennen, muss der Effekt der einzelnen Faktoren auf die Verteilung betrachtet werden. (orig.)

  1. Geochemical and isotopic approach to maturity/source/mixing estimations for natural gas and associated condensates in the Thrace Basin, NW Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Guergey, Kadir [University of Pamukkale, Geological Engineering Department, Kinikli Campus, 20070 Denizli (Turkey)]. E-mail: kgurgey@pamukkale.edu.tr; Philp, R. Paul [Geology and Geophysics, University of Oklahoma, Norman, OK 73019 (United States); Clayton, Chris [High Bank House, Eardiston, Tenbury Wells, Worcestershire, WR15 8JJ (United Kingdom); Emiroglu, Hasan [Turkish Petroleum Corporation, Exploration Group, Soeguetoezue, Ankara (Turkey); Siyako, Muzaffer [Turkish Petroleum Corporation, Exploration Group, Soeguetoezue, Ankara (Turkey)

    2005-11-15

    The Tertiary Thrace Basin located in NW Turkey comprises 9 km of clastic-sedimentary column ranging in age from Early Eocene to Recent in age. Fifteen natural gas and 10 associated condensate samples collected from the 11 different gas fields along the NW-SE extending zone of the northern portion of the basin were evaluated on the basis of their chemical and individual C isotopic compositions. For the purpose of the study, the genesis of CH{sub 4}, thermogenic C{sub 2+} gases, and associated condensates were evaluated separately. Methane appears to have 3 origins: Group-1 CH{sub 4} is bacteriogenic (Calculated {delta} {sup 13}C{sub C1-C} = -61.48%o; Silivri Field) and found in Oligocene reservoirs and mixed with the thermogenic Group-2 CH{sub 4}. They probably formed in the Upper Oligocene coal and shales deposited in a marshy-swamp environment of fluvio-deltaic settings. Group-2 ({delta} {sup 13}C{sub C1-C} = -35.80%o; Hamitabat Field) and Group-3 ({delta} {sup 13}C{sub 1-C} = -49.10%o; Degirmenkoey Field) methanes are thermogenic and share the same origin with the Group-2 and Group-3 C{sub 2+} gases. The Group-2 C{sub 2+} gases include 63% of the gas fields. They are produced from both Eocene (overwhelmingly) and Oligocene reservoirs. These gases were almost certainly generated from isotopically heavy terrestrial kerogen ({delta} {sup 13}C = -21%o) present in the Eocene deltaic Hamitabat shales. The Group-3 C{sub 2+} gases, produced from one field, were generated from isotopically light marine kerogen ({delta} {sup 13}C = -29%o). Lower Oligoce ne Mezardere shales deposited in pro-deltaic settings are believed to be the source of these gases. The bulk and individual n-alkane isotopic relationships between the rock extracts, gases, condensates and oils from the basin differentiated two Groups of condensates, which can be genetically linked to the Group-2 and -3 thermogenic C{sub 2+} gases. However, it is crucial to note that condensates do not necessarily correlate

  2. Simultaneous Analyses and Applications of Multiple Fluorobenzoate and Halide Tracers in Hydrologic Studies

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Moran, J E

    2004-01-22

    An analytical method that employs ion chromatography has been developed to more fully exploit the use of fluorobenzoic acids (FBAs) and halides as hydrologic tracers. In a single run, this reliable, sensitive, and robust method can simultaneously separate and quantify halides (fluoride, chloride, bromide, and iodide) and up to seven FBAs from other common groundwater constituents (e.g., nitrate and sulfate). The usefulness of this ion chromatographic (IC) analytical method is demonstrated in both field and laboratory tracer experiments. Field experiments in unsaturated tuff featuring fractures or a fault show that this efficient and cost-effective method helps achieve the objectives of tracer studies that use multiple FBAs and/or diffusivity tracers (simultaneous use of one or more FBA and halide). The field study examines the hydrologic response of fractures and the matrix to different flow rates and the contribution of matrix diffusion in chemical transport. Laboratory tracer experiments with eight geologic media from across the United States--mostly from Department of Energy facilities where groundwater contamination is prevalent and where subsurface characterization employing tracers has been ongoing or is in need--reveal several insights about tracer transport behavior: (1) Bromide and FBAs are not always transported conservatively. (2) The delayed transport of these anionic tracers is likely related to geologic media characteristics, such as organic matter, pH, iron oxide content, and clay mineralogy. (3) Any use of iodine as a hydrologic tracer should take into account the different sorption behaviors of iodide and iodate and the possible conversion of iodine's initial chemical form. (4) The transport behavior of potential FBA and halide tracers under relevant geochemical conditions should be evaluated before beginning ambitious, large-scale field tracer experiments.

  3. Simultaneous Analyses and Applications of Multiple Fluorobenzoate and Halide Tracers in Hydrologic Studies

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Moran, J E

    2004-01-22

    An analytical method that employs ion chromatography has been developed to more fully exploit the use of fluorobenzoic acids (FBAs) and halides as hydrologic tracers. In a single run, this reliable, sensitive, and robust method can simultaneously separate and quantify halides (fluoride, chloride, bromide, and iodide) and up to seven FBAs from other common groundwater constituents (e.g., nitrate and sulfate). The usefulness of this ion chromatographic (IC) analytical method is demonstrated in both field and laboratory tracer experiments. Field experiments in unsaturated tuff featuring fractures or a fault show that this efficient and cost-effective method helps achieve the objectives of tracer studies that use multiple FBAs and/or diffusivity tracers (simultaneous use of one or more FBA and halide). The field study examines the hydrologic response of fractures and the matrix to different flow rates and the contribution of matrix diffusion in chemical transport. Laboratory tracer experiments with eight geologic media from across the United States--mostly from Department of Energy facilities where groundwater contamination is prevalent and where subsurface characterization employing tracers has been ongoing or is in need--reveal several insights about tracer transport behavior: (1) Bromide and FBAs are not always transported conservatively. (2) The delayed transport of these anionic tracers is likely related to geologic media characteristics, such as organic matter, pH, iron oxide content, and clay mineralogy. (3) Any use of iodine as a hydrologic tracer should take into account the different sorption behaviors of iodide and iodate and the possible conversion of iodine's initial chemical form. (4) The transport behavior of potential FBA and halide tracers under relevant geochemical conditions should be evaluated before beginning ambitious, large-scale field tracer experiments.

  4. Radon as geological tracer

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, T.; Anjos, R.M. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Valladares, D.L.; Rizzotto, M.; Velasco, H.; Ayub, J. Juri [Universidad Nacional de San Luis (Argentina). Inst. de Matematica Aplicada San Luis (IMASL); Silva, A.A.R. da; Yoshimura, E.M. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica

    2012-07-01

    Full text: This work presents measurements of {sup 222}Rn levels performed in La Carolina gold mine and Los Condores tungsten mine at the province of San Luis, Argentina, today used for tourist visitation, and can evaluate the potential use of such radioactive noble gas as tracer or marker for geological processes in underground environments. By concentrations of {sup 40}K, {sup 232}Th and {sup 23}'8U were also measured in the walls of tunnels were determined the rocks mineral composition, what indicated that the mines have the same composition. In this sense, we used nuclear trace plastic detectors CR-39, gamma spectrometry of rock samples and Geiger-Muller (GM) monitors The patterns of radon gas transportation processes revealed that La Carolina could be interpreted through a model based on a radioactive gas confined into a single entrance tube, with constant cross section and air velocity. Los Condores, which has a second main entrance, could be interpreted through a model based on a radioactive gas confined into a two entrance tube, allowing a chimney effect for air circulation. The results showed the high potential of using {sup 222}Rn as a geological tracer. In what concerns the occupational hazard, in summer (time of more intense tourist activity in the mine) La Carolina presented a mean concentration of the radioactive noble gas that exceeds in four times the action level of 1,5 kBq m{sup -3} recommended by the International Commission of Radiological Protection (ICRP). The chimney effect shows the low mean concentration of radon in Los Condores. (author)

  5. Exotic tracers for atmospheric studies

    Energy Technology Data Exchange (ETDEWEB)

    Lovelock, J.E. (Brazzos Ltd., Launceston (UK)); Ferber, G.J. (National Oceanic and Atmospheric Administration, Silver Spring, MD (USA). Air Resources Lab.)

    1982-01-01

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximise research benefits.

  6. Exotic tracers for atmospheric studies

    Science.gov (United States)

    Lovelock, James E.; Ferber, Gilbert J.

    Tracer materials can be injected into the atmosphere to study transport and dispersion processes and to validate air pollution model calculations. Tracers should be inert, non-toxic and harmless to the environment. Tracers for long-range experiments, where dilution is very great, must be measurable at extremely low concentrations, well below the parts per trillion level. Compounds suitable for long-range tracer work are rare and efforts should be made to reserve them for meteorological studies, barring them from commercial uses which would increase atmospheric background concentrations. The use of these exotic tracers, including certain perfluorocarbons and isotopically labelled methanes, should be coordinated within the meteorological community to minimize interferences and maximize research benefits.

  7. Geochemical baseline studies of soil in Finland

    Science.gov (United States)

    Pihlaja, Jouni

    2017-04-01

    The soil element concentrations regionally vary a lot in Finland. Mostly this is caused by the different bedrock types, which are reflected in the soil qualities. Geological Survey of Finland (GTK) is carrying out geochemical baseline studies in Finland. In the previous phase, the research is focusing on urban areas and mine environments. The information can, for example, be used to determine the need for soil remediation, to assess environmental impacts or to measure the natural state of soil in industrial areas or mine districts. The field work is done by taking soil samples, typically at depth between 0-10 cm. Sampling sites are chosen to represent the most vulnerable areas when thinking of human impacts by possible toxic soil element contents: playgrounds, day-care centers, schools, parks and residential areas. In the mine districts the samples are taken from the areas locating outside the airborne dust effected areas. Element contents of the soil samples are then analyzed with ICP-AES and ICP-MS, Hg with CV-AAS. The results of the geochemical baseline studies are published in the Finnish national geochemical baseline database (TAPIR). The geochemical baseline map service is free for all users via internet browser. Through this map service it is possible to calculate regional soil baseline values using geochemical data stored in the map service database. Baseline data for 17 elements in total is provided in the map service and it can be viewed on the GTK's web pages (http://gtkdata.gtk.fi/Tapir/indexEN.html).

  8. A theoretical framework of tracer methods for marine sediment dynamics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new theoretical framework of tracer methods is proposed in the present contribution, on the basis of mass conservation. This model is applicable for both artificial and natural tracers. It can be used to calculate the spatial distribution patterns of sediment transport rate, thus providing independent information and verification for the results derived from empirical formulae. For the procedures of the calculation, first, the tracer concentration and topographic maps of two times are obtained. Then, the spatial and temporal changes in the concentration and seabed elevation are calculated, and the boundary conditions required are determined by field observations (such as flow and bedform migration measurements). Finally, based upon eqs. (1) and (13), the transport rate is calculated and expressed as a function of the position over the study area. Further, appropriate modifications to the model may allow the tracer to have different densities and grain size distributions from the bulk sediment.

  9. The IUGS/IAGC Task Group on Global Geochemical Baselines

    Institute of Scientific and Technical Information of China (English)

    David B.Smith; Shaun Reeder; Alecos Demetriades

    2012-01-01

    The Task Group on Global Geochemical Baselines,operating under the auspices of both the International Union of Geological Sciences(IUGS) and the International Association of Geochemistry(IAGC),has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth's surface or near-surface environment.The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified.In order to accomplish this long-term goal,the activities of the Task Group include:(1) developing partnerships with countries conducting broad-scale geochemical mapping studies;(2) providing consultation and training in the form of workshops and short courses;(3) organizing periodic international symposia to foster communication among the geochemical mapping community;(4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database;(5) acting as a repository for data collected by those projects meeting the criteria for standardization;(6) preparing complete metadata for the certified projects;and(7) preparing,ultimately,a global geochemical database.This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

  10. The IUGS/IAGC Task Group on Global Geochemical Baselines

    Science.gov (United States)

    Smith, David B.; Wang, Xueqiu; Reeder, Shaun; Demetriades, Alecos

    2012-01-01

    The Task Group on Global Geochemical Baselines, operating under the auspices of both the International Union of Geological Sciences (IUGS) and the International Association of Geochemistry (IAGC), has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth’s surface or near-surface environment. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified. In order to accomplish this long-term goal, the activities of the Task Group include: (1) developing partnerships with countries conducting broad-scale geochemical mapping studies; (2) providing consultation and training in the form of workshops and short courses; (3) organizing periodic international symposia to foster communication among the geochemical mapping community; (4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database; (5) acting as a repository for data collected by those projects meeting the criteria for standardization; (6) preparing complete metadata for the certified projects; and (7) preparing, ultimately, a global geochemical database. This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

  11. Proceedings of the atmospheric tracers and tracer application workshop

    Energy Technology Data Exchange (ETDEWEB)

    Barr, S.; Gedayloo, T. (comps.)

    1979-12-01

    In addition to presentations by participating members a general discussion was held in order to summarize and outline the goals and objectives of the workshop. A number of new low level background tracers such as heavy methanes, perfluorocarbons, multiply labeled isotopes such as /sup 13/C/sup 18/O/sub 2/, helium 3, in addition to sample collection techniques and analytical methods for various tracers were discussed. This report is a summary of discussions and papers presented at this workshop.

  12. MULTISPECIES REACTIVE TRACER TEST IN A SAND AND GRAVEL AQUIFER, CAPE COD, MASSACHUSETTS: PART 2: TRANSPORT OF CHROMIUM (VI) AND LEAD-, COPPER-, AND ZINC-EDTA TRACERS

    Science.gov (United States)

    This report discusses the transport of a group of reactive tracers over the course of a large-scale, natural gradient tracer test conducted at the USGS Cape Cod Toxic Substances Hydrology Research site, near Falmouth, Massachusetts. The overall objectives of the experiment were ...

  13. Very Massive Tracers and Higher Derivative Biases

    CERN Document Server

    Fujita, Tomohiro; Senatore, Leonardo; Vlah, Zvonimir; Angulo, Raul

    2016-01-01

    Most of the upcoming cosmological information will come from analyzing the clustering of the Large Scale Structures (LSS) of the universe through LSS or CMB observations. It is therefore essential to be able to understand their behavior with exquisite precision. The Effective Field Theory of Large Scale Structures (EFTofLSS) provides a consistent framework to make predictions for LSS observables in the mildly non-linear regime. In this paper we focus on biased tracers. We argue that in calculations at a given order in the dark matter perturbations, highly biased tracers will underperform because of their larger higher derivative biases. A natural prediction of the EFTofLSS is therefore that by simply adding higher derivative biases, all tracers should perform comparably well. We implement this prediction for the halo-halo and the halo-matter power spectra at one loop, and the halo-halo-halo, halo-halo-matter, and halo-matter-matter bispectra at tree-level, and compare with simulations. We find good agreement ...

  14. A New Geochemical Classification of Elements

    Institute of Scientific and Technical Information of China (English)

    Qi Changmou; L. Lynn Chyi

    2001-01-01

    The geochemical classification proposed by Goldschmidt was based on meteoritic analysis and elemental partition in blast furnace. There are many surprises when applied to the discussion of natural occurrences. A modified classification of elements based on basic chemical properties and their occurrences. A modified classification of elements based on basic chemical properties and their occurrences in nature is, therefore, proposed for students learning geochemistry and geologists working in the field. Elements are classified into six groups including lithophile, oxyphile, siderophile, chalcophile, biophile, and atmophile elements. Five terms are taken from Goldshcmidt's original classification. Oxyphile is a new term.

  15. Concerning evaluation of eco-geochemical background in remediation strategy

    Science.gov (United States)

    Korobova, Elena; Romanov, Sergey

    2015-04-01

    The geochemical concept of biosphere developed by V.I. Vernadsky states the geological role of the living organisms in the course of their active chemical interaction with the inert matter (Vernadsky, 1926, 1960). Basing on this theory it is reasonable to suggest that coevolution of living organisms and their environment led to development of the dynamically stable biogeocenoses precisely adequate to their geochemical environment. Soil cover was treated by V.I. Vernadsky as a balanced bio-inert matter resulting from this interaction. Appearance of human mind and then a civilization led to global expansion of human beings, first able to survive in unfavorable geochemical conditions and then starting chemical transformation of the environment to satisfy the growing demands of mankind in food and energy. The residence in unfavorable environment and local contamination was followed by appearance of endemic diseases of plants, animals and man. Therefore zonal, regional and local chemical composition of the soil cover formed in natural conditions may be used for estimation of the optimum geochemical background, most adequate for the corresponding zonal biogeocenoses and species. Moreover, the natural geochemical background and technogenic fields have unequal spatial structure and this facilitates their identification that may be relatively easy realized in remediation strategy. On the assumption of the foregoing, the adequate methodical approach to remediation of technogenically affected areas should account of the interaction of the existing natural and the newly formed technogenic geochemical fields and include the following steps: 1) the study and mapping of geochemical structure of the natural geochemical background basing on soil maps; 2) the study of contaminants and mapping spatial distribution of technogenic releases; 3) construction of risk maps for the target risk groups with due regard to natural ecological threshold concentration in context of risk degree for

  16. Driven tracers in narrow channels

    Science.gov (United States)

    Cividini, J.; Mukamel, D.; Posch, H. A.

    2017-01-01

    Steady-state properties of a driven tracer moving in a narrow two-dimensional (2D) channel of quiescent medium are studied. The tracer drives the system out of equilibrium, perturbs the density and pressure fields, and gives the bath particles a nonzero average velocity, creating a current in the channel. Three models in which the confining effect of the channel is probed are analyzed and compared in this study: the first is the simple symmetric exclusion process (SSEP), for which the stationary density profile and the pressure on the walls in the frame of the tracer are computed. We show that the tracer acts like a dipolar source in an average velocity field. The spatial structure of this 2D strip is then simplified to a one-dimensional (1D) SSEP, in which exchanges of position between the tracer and the bath particles are allowed. Using a combination of mean-field theory and exact solution in the limit where no exchange is allowed gives good predictions of the velocity of the tracer and the density field. Finally, we show that results obtained for the 1D SSEP with exchanges also apply to a gas of overdamped hard disks in a narrow channel. The correspondence between the parameters of the SSEP and of the gas of hard disks is systematic and follows from simple intuitive arguments. Our analytical results are checked numerically.

  17. [Microbial geochemical calcium cycle].

    Science.gov (United States)

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  18. Tracer Diffusion in a Soft Glassy Material

    Science.gov (United States)

    Petit, Laure; Barentin, Catherine; Colombani, Jean; Ybert, Christophe; Barrat, Jean-Louis; Bocquet, Lydéric

    2008-07-01

    We have carried out Fluorescence Recovery After Photobleaching measurements of the diffusion of tracers of various sizes in a colloidal glass (a Laponite suspension). We have shown that the diffusion is only dependent on the ratio of the tracer size and the distance between Laponite disks. This suggests that the tracer diffusion hindrance in the glass stems from the hydrodynamical interactions between the tracer and the Laponite network, the physico-chemical Laponite-tracer interaction playing a negligible role.

  19. Collected radiochemical and geochemical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Kleinberg, J [comp.

    1990-05-01

    This revision of LA-1721, 4th Ed., Collected Radiochemical Procedures, reflects the activities of two groups in the Isotope and Nuclear Chemistry Division of the Los Alamos National Laboratory: INC-11, Nuclear and radiochemistry; and INC-7, Isotope Geochemistry. The procedures fall into five categories: I. Separation of Radionuclides from Uranium, Fission-Product Solutions, and Nuclear Debris; II. Separation of Products from Irradiated Targets; III. Preparation of Samples for Mass Spectrometric Analysis; IV. Dissolution Procedures; and V. Geochemical Procedures. With one exception, the first category of procedures is ordered by the positions of the elements in the Periodic Table, with separate parts on the Representative Elements (the A groups); the d-Transition Elements (the B groups and the Transition Triads); and the Lanthanides (Rare Earths) and Actinides (the 4f- and 5f-Transition Elements). The members of Group IIIB-- scandium, yttrium, and lanthanum--are included with the lanthanides, elements they resemble closely in chemistry and with which they occur in nature. The procedures dealing with the isolation of products from irradiated targets are arranged by target element.

  20. The geochemical Phenomenon-Local geochemical fields in a glacier (scientific note)

    OpenAIRE

    V. N., Makarov

    2001-01-01

    Geochemical fields in alpine cold and warm glaciers were studied. Local geochemical fields of typomorphic elements were found to form in the ice and on the surface of glaciers overlying ore bodies and endogenic geochemical haloes. The formation of local cryogenic geochemical fields in the glaciers results from sharp geochemical heterogeneity and geochemical processes in underlying rocks which cause cryogenic migration of chemical elements and compounds in the glacier. The thickness of geochem...

  1. The geochemical Phenomenon-Local geochemical fields in a glacier (scientific note)

    OpenAIRE

    V. N., Makarov

    2001-01-01

    Geochemical fields in alpine cold and warm glaciers were studied. Local geochemical fields of typomorphic elements were found to form in the ice and on the surface of glaciers overlying ore bodies and endogenic geochemical haloes. The formation of local cryogenic geochemical fields in the glaciers results from sharp geochemical heterogeneity and geochemical processes in underlying rocks which cause cryogenic migration of chemical elements and compounds in the glacier. The thickness of geochem...

  2. Achievements and opportunities from ESF Research Networking Programme: Natural molecular structures as drivers and tracers of terrestrial C fluxes, and COST Action 639: Greenhouse gas budget of soils under changing climate and land use

    Science.gov (United States)

    Boeckx, P.; Rasse, D.; Jandl, R.

    2009-04-01

    One of the activities of the European Science Foundation (ESF, www.esf.org) is developing European scale Research Networking Programmes (RNPs). RNPs lay the foundation for nationally funded research groups to address major scientific and research infrastructure issues, in order to advance the frontiers of existing science. MOLTER (www.esf.org/molter or www.molter.no) is such an RNP. MOLTER stands for "Natural molecular structures as drivers and tracers of terrestrial C fluxes" aims at stimulating the use of isotopic and organic chemistry to study carbon stabilization and biogeochemistry in terrestrial ecosystems and soils in particular. The understanding of the formation, stabilization and decomposition of complex organic compounds in the environment is currently being revolutionized by advanced techniques in identification, quantification, and origin tracing of functional groups and individual molecules. MOLTER focuses on five major research themes: - Molecular composition and turnover time of soil organic matter; - Plant molecular structures as drivers of C stabilisation in soils; - Fire transformations of plant and soil molecular structures - Molecular markers in soils; - Dissolved organic molecules in soils: origin, functionality and transport. These research themes are covered via the following activities: - Organisation of international conferences; - Organisation of specific topical workshops; - Organisation of summer schools for PhD students; - Short- and long-term exchange grants for scientists. MOLTER is supported by research funding or performing agencies from Austria, Belgium, France, Germany, the Netherlands, Norway, Romania, Spain, Sweden, Switzerland and the United Kingdom. The ESF is also the implementing agency of COST (European Cooperation in Science and Technology, www.cost.esf.org), one of the longest-running European instruments supporting cooperation among scientists and researchers across Europe. COST Action 639 "Greenhouse gas budget of

  3. Reconnaissance soil geochemical survey of Gibraltar.

    Science.gov (United States)

    Mesilio, Liesl; Farago, Margaret E; Thornton, Iain

    2003-03-01

    The extreme density of population of Gibraltar, situated at the southern tip of Spain, exerts considerable pressure on land use and thus future planning is of utmost importance. An initial reconnaissance soil geochemical survey of Gibraltar was based on 120 surface samples (0-15 cm) taken from a wide range of exposed, either bare soil or vegetated sites, to provide the optimum geographical distribution. The 'total' elemental concentrations of 26 elements (Li, Na, K, Be, Mg, Ca, Sr, Ba, Al, La, Ti, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Pb, P, S, As) were determined by nitric/percholric acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The reconnaissance data shows that the spatial distribution of various elements depended on previous and present land use. Most elements (Ca, Cr, Mg and Mn excluded) exhibited relatively high concentrations in civilian and natural soils. Trends have been established for many elements, and concentrations exceeding guideline values have been found in certain areas of Gibraltar. This reconnaissance of Gibraltar is at present being followed by a more detailed baseline geochemical survey, which will establish the extent and magnitude of the variations in major and trace elements in soils and dusts, assess the impact of industrial, commercial and urban development on the geochemical landscape and to make recommendations concerning sustainable development.

  4. AN INTEGRATED APPROACH TO CHARACTERIZING BYPASSED OIL IN HETEROGENEOUS AND FRACTURED RESERVOIRS USING PARTITIONING TRACERS

    Energy Technology Data Exchange (ETDEWEB)

    Akhil Datta-Gupta

    2003-08-01

    We explore the use of efficient streamline-based simulation approaches for modeling partitioning interwell tracer tests in hydrocarbon reservoirs. Specifically, we utilize the unique features of streamline models to develop an efficient approach for interpretation and history matching of field tracer response. A critical aspect here is the underdetermined and highly ill-posed nature of the associated inverse problems. We have adopted an integrated approach whereby we combine data from multiple sources to minimize the uncertainty and non-uniqueness in the interpreted results. For partitioning interwell tracer tests, these are primarily the distribution of reservoir permeability and oil saturation distribution. A novel approach to multiscale data integration using Markov Random Fields (MRF) has been developed to integrate static data sources from the reservoir such as core, well log and 3-D seismic data. We have also explored the use of a finite difference reservoir simulator, UTCHEM, for field-scale design and optimization of partitioning interwell tracer tests. The finite-difference model allows us to include detailed physics associated with reactive tracer transport, particularly those related with transverse and cross-streamline mechanisms. We have investigated the potential use of downhole tracer samplers and also the use of natural tracers for the design of partitioning tracer tests. Finally, the behavior of partitioning tracer tests in fractured reservoirs is investigated using a dual-porosity finite-difference model.

  5. The Geochemical Behavior and Transport Characteristics of Xenoestrogens

    Science.gov (United States)

    Wallace, T. C.; Bennett, P. C.

    2003-12-01

    Xenoestrogens are estrogenic active synthetic chemicals that mimic the actions of female sex hormones. Xenoestrogens can be produced synthetically and naturally, and exposure can occur from a variety of sources- food additives, plastics, pesticides, or pharmaceuticals. These environmental chemicals are also known as endocrine disruptors because exposure to low doses (ng/L) have been linked to adverse effects in the reproductive and developmental stages in aquatic species (i.e. reproductive anomalies, feminization, infertility, alterations in growth during life cycles, and changes in community structures). Determining the exposure risks of these toxicological compounds, however, requires a better understanding of the geochemical behavior and transport of synthetic estrogens it is discharged to. Estrogen and its metabolites are also useful tracers because of their specific medical usage (sources from birth control pills, estrogen replacement therapy, and livestock farming), slow degradation before excretion, and unique physiochemical properties (low volatility, hydrophobicity, and high Kow). Estradiol concentrations analyzed by an enzyme-linked immunoassay (ELISA) show that <2-55 ng/L are discharged to Walnut Creek, a stream that also connects to the Colorado River(TX). The bioavailability of these compounds is affected by sorption processes, where xenoestrogens become associated with solid phases. A series of batch sorption experiments using sediment collected from Walnut Creek downstream of an Austin waste water treatment plant and synthetic estrogen standards (Simga@ Estrone, 17B-Estradiol, and Estriol), examined the distribution of estrogen between solid and aqueous phases. Analysis of the concentrations sorbed to sediment result in Freundlich sorption isotherms using HPLC/UV techniques (High Performance Liquid Chromatography with UV detectors- 220 and 280nm). Sorption occurs rapidly with 98% of 17B-Estradiol sorbed within 30 minutes (Estriol=80%, Estrone=95

  6. Differentiated availability of geochemical mercury pools controls methylmercury levels in estuarine sediment and biota.

    Science.gov (United States)

    Jonsson, Sofi; Skyllberg, Ulf; Nilsson, Mats B; Lundberg, Erik; Andersson, Agneta; Björn, Erik

    2014-08-20

    Neurotoxic methylmercury (MeHg) formed from inorganic divalent mercury (Hg(II)) accumulates in aquatic biota and remains at high levels worldwide. It is poorly understood to what extent different geochemical Hg pools contribute to these levels. Here we report quantitative data on MeHg formation and bioaccumulation, in mesocosm water-sediment model ecosystems, using five Hg(II) and MeHg isotope tracers simulating recent Hg inputs to the water phase and Hg stored in sediment as bound to natural organic matter or as metacinnabar. Calculations for an estuarine ecosystem suggest that the chemical speciation of Hg(II) solid/adsorbed phases control the sediment Hg pool's contribution to MeHg, but that input of MeHg from terrestrial and atmospheric sources bioaccumulates to a substantially greater extent than MeHg formed in situ in sediment. Our findings emphasize the importance of MeHg loadings from catchment runoff to MeHg content in estuarine biota and we suggest that this contribution has been underestimated.

  7. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  8. Synthesis and characterization of environmentally friendly fluorescent particle tracers

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Rapiti, Emiliano; Grimaldi, Salvatore

    2013-04-01

    Tracers are widely used in experimental fluid mechanics and hydrology to investigate complex flows and water cycle processes. Commonly used tracers include dyes, artificial tracers, naturally occurring isotopes and chemicals, microorganisms, and DNA-based systems. Tracers should be characterized by low detection limits and high accuracy in following water paths and flow structures. For natural studies, tracers are also expected to be nontoxic and with low sorption affinity to natural substrates to minimize losses in the environment. In this context, while isotopes are completely natural, their use in field studies is limited by their ubiquity and, therefore, by the high uncertainty in data processing methodologies. Further, the use of dyes and artificial tracers can be hampered by extremely low detection limits due to dilution in natural streams and microorganisms, while DNA-based system may require physical sampling and time-consuming functionalization and detection procedures. In this work, we present the synthesis and characterization of fluorescent beads incorporating an eco-compatible fluorophore for environmental and laboratory applications. The particles are synthesized from natural beeswax through an inexpensive thermal procedure and can be engineered to present variable densities and diameters. A thorough characterization of their surface morphology at the nanoscale, crystal structure and size, chemical composition, and dye incorporation into the beeswax matrix is described by using a wide array of microscopy techniques. In addition, the particle fluorescence response is studied by performing excitation and emission scans on melted beeswax bead samples. The feasibility of using the synthesized particles in environmental settings is assessed through the design of ad-hoc weathering agent experiments where the beads are exposed to high energy radiation and hot water. Further, a proof of concept test is described to understand the particles' potential as a

  9. Estimation of Recharge from Long-Term Monitoring of Saline Tracer Transport Using Electrical Resistivity Tomography

    DEFF Research Database (Denmark)

    Haarder, Eline Bojsen; Jensen, Karsten Høgh; Binley, Andrew;

    2015-01-01

    The movement of a saline tracer added to the soil surface was monitored in the unsaturated zone using cross-borehole electrical resistivity tomography (ERT) and subjected to natural rainfall conditions. The ERT data were inverted and corrected for subsurface temperature changes, and spatial moment...... methods. In September 2011, a saline tracer was added across a 142-m2 area at the surface at an application rate mimicking natural infiltration. The movement of the saline tracer front was monitored using cross-borehole electrical resistivity tomography (ERT); data were collected on a daily to weekly...... basis and continued for 1 yr after tracer application. The ERT data were inverted and corrected for temperature changes in the subsurface, and spatial moment analysis was used to calculate the tracer mass, position of the center of mass, and thereby the downwardly recharging flux. The recovered mass...

  10. Polyethyleneimine as tracer for electron microscopy

    NARCIS (Netherlands)

    Schurer, Jacob Willem

    1980-01-01

    In this thesis the development of a tracer particle for use in electron microscopy is described. Attempts were made to use this tracer particle in immuno-electron microscopy and to trace negatively charged tissue components. ... Zie: Summary

  11. 238U-234U activity ratio as tracer of waterpathway within the watershed substratum: evidence of U data from the Strengbach and Ringelbach research catchments (Vosges , France)

    Science.gov (United States)

    Chabaux, F.; Schaffhausen, Th.; Pierret, M.-C.; Ambroise, B.

    2012-04-01

    U activity ratios were measured in spring and source waters collected in two small research watersheds developed on granitic bedrocks in Vosges Mountains (Eastern France), i.e., the Strengbach (http://ohge.u-strasbg.fr) and the Ringelbach catchments. The data indicates a clear relationship between the emerging altitude of sources/springs in each slope of the watersheds, and the intensity of 234U-238U activity ratios in the waters. Such a relationship can be readily explained through a scenario assuming that U mobilization in these waters and their 234U enrichment (consequence of the alpha recoil process) are controlled by the duration of the water-pathway within the substratum of the watershed: longer water pathway within the watershed, longer duration of water-rock interaction and hence higher 234U enrichment in the source/spring waters. The immediate consequence of such an interpretation is that (234U/238U) activity ratio in surface waters, at least at the scale of such small and elemental watersheds, might be a geochemical tracer useful to constrain a key hydrological parameter which controls, at least partly, the nature and the intensity of water-rock interactions in the watershed, namely the water pathway within the watershed substratum. The data also suggests that U activity ratios could be also very relevant to constrain the contribution of deep waters within surface waters. Future developments in this domain will certainly confirm the interest of U activity ratio as hydrological tracer of the water-rock interactions.

  12. Fractured-rock hydrogeophysics with electrically conductive and neutrally buoyant tracers

    Science.gov (United States)

    Shakas, A.; Linde, N.; Baron, L.; Le Borgne, T.; Bour, O.; Lavenant, N.; Gerard, M. F.

    2016-12-01

    Artificial tracer tests help to characterize and understand the dynamics of groundwater systems. This remains a challenging task, especially when dealing with highly heterogeneous formations in which flow can be very localized and the interpretation of tracer breakthrough curves may be ambiguous. As a complement to tracer tests, ground-penetrating radar (GPR) and electrical resistivity tomography can map the space-time migration of electrically conductive tracers. In hydrogeophysics, the most common tracer is dissolved table salt in water. However, conventional salt tracers lead to density effects that are often ignored. Even less than 1% density variations can have a dramatic effect on transport behavior and affect tracer tests in complex ways. Such effects have been demonstrated in our previous experiments that used single-hole GPR to monitor saline push-pull tests in fractured granite. It is possible to model density effects, but this leads to computational complexity and field dynamics that are not necessarily representative of the natural responses of the system. To minimize density effects, we performed a new set of push-pull tests using a neutrally buoyant and electrically conductive tracer at the same test site located close to Ploemeur, France. This novel tracer consists of a mixture of salt (NaCl), water and pure ethanol. Ethanol has a density of 789 g/L at 20° C and is used to counter-act the salt-induced density increase. Our GPR time-lapse images and tracer breakthrough data indicate a largely reversible transport process that confirms the neutral buoyancy of the tracer. Ethanol is biodegradable and does not pose significant environmental issues. Furthermore, calibration of the neutral-buoyant mixture is straightforward to perform in the field using Archimedes principle. Based on these results, we argue that neutrally buoyant ethanol-salt-water mixtures are ideal for a wide variety of hydrogeophysical tracer tests in porous or fractured media.

  13. Modeling Low-temperature Geochemical Processes

    Science.gov (United States)

    Nordstrom, D. K.

    2003-12-01

    Geochemical modeling has become a popular and useful tool for a wide number of applications from research on the fundamental processes of water-rock interactions to regulatory requirements and decisions regarding permits for industrial and hazardous wastes. In low-temperature environments, generally thought of as those in the temperature range of 0-100 °C and close to atmospheric pressure (1 atm=1.01325 bar=101,325 Pa), complex hydrobiogeochemical reactions participate in an array of interconnected processes that affect us, and that, in turn, we affect. Understanding these complex processes often requires tools that are sufficiently sophisticated to portray multicomponent, multiphase chemical reactions yet transparent enough to reveal the main driving forces. Geochemical models are such tools. The major processes that they are required to model include mineral dissolution and precipitation; aqueous inorganic speciation and complexation; solute adsorption and desorption; ion exchange; oxidation-reduction; or redox; transformations; gas uptake or production; organic matter speciation and complexation; evaporation; dilution; water mixing; reaction during fluid flow; reaction involving biotic interactions; and photoreaction. These processes occur in rain, snow, fog, dry atmosphere, soils, bedrock weathering, streams, rivers, lakes, groundwaters, estuaries, brines, and diagenetic environments. Geochemical modeling attempts to understand the redistribution of elements and compounds, through anthropogenic and natural means, for a large range of scale from nanometer to global. "Aqueous geochemistry" and "environmental geochemistry" are often used interchangeably with "low-temperature geochemistry" to emphasize hydrologic or environmental objectives.Recognition of the strategy or philosophy behind the use of geochemical modeling is not often discussed or explicitly described. Plummer (1984, 1992) and Parkhurst and Plummer (1993) compare and contrast two approaches for

  14. Geochemical Origin of Biological Molecules

    Science.gov (United States)

    Bassez, Marie-Paule

    2013-04-01

    Conference and abstract in OLEB, 2008, 39 (3-4) 223. BASSEZ M.P. 2009 Prebiotic synthesis under hydothermal conditions, C. R. Chimie, Académie des Sciences, Paris 12 (6-7) : 801-807. BASSEZ M.P. 2012 A model for a geochemical origin of life in preparation BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009a Organic analysis of peridotite rocks from Ashadze and Logatchev hydrothermal sites, Int. J. Mol. Sci. 10(7): 2986-2998. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2009b Organic analysis of peridotite rocks from the MAR, AGU fall meeting, P43C-1441, San Francisco, 14-18/12/2009. BASSEZ M.P., TAKANO Y. 2010a Prebiotic organic globules, Nature Precedings: Posted 21 Jul http://hdl:10101/npre.2010.4694.1. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2010b Organic analysis of peridotite rocks, First chemical steps towards the Origin of Life colloquium, Turin 16-17/09/2010. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011a A search for prebiotic molecular signatures inside rocks, Geobiology in Space exploration workshop, P sans n°, Marrakech 07-14/02/2011. BASSEZ M.P., TAKANO Y., OHKOUCHI N. 2011b Detection of molecular biosignatures inside rocks, Origins 2011 ISSOL and Bioastronomy conference, P2-17, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y., 2011c Organic microstructures, Origins 2011 ISSOL and Bioastronomy conference, P2-34, Montpellier, 04-08/07/2011. BASSEZ M.P., TAKANO Y. KOBAYASHI K. 2011d Prebiotic organic microstructures, Nature Precedings: Posted 14 Nov. http://hdl.handle.net/10101/npre.2011.4694.2 BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012a Prebiotic organic microstructures, Origin of Life Gordon Research Conference P4, Galveston, 08-13/01/2012. BASSEZ M.P., TAKANO Y., KOBAYASHI K. 2012b Prebiotic organic microstructures, Orig. Life Evol. Biosph. 42 (4) : 307-316.

  15. Tracer-tracer relations as a tool for research on polar ozone loss

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Rolf

    2010-07-01

    The report includes the following chapters: (1) Introduction: ozone in the atmosphere, anthropogenic influence on the ozone layer, polar stratospheric ozone loss; (2) Tracer-tracer relations in the stratosphere: tracer-tracer relations as a tool in atmospheric research; impact of cosmic-ray-induced heterogeneous chemistry on polar ozone; (3) quantifying polar ozone loss from ozone-tracer relations: principles of tracer-tracer correlation techniques; reference ozone-tracer relations in the early polar vortex; impact of mixing on ozone-tracer relations in the polar vortex; impact of mesospheric intrusions on ozone-tracer relations in the stratospheric polar vortex calculation of chemical ozone loss in the arctic in March 2003 based on ILAS-II measurements; (4) epilogue.

  16. A Systematic Method For Tracer Test Analysis: An Example Using Beowawe Tracer Data

    Energy Technology Data Exchange (ETDEWEB)

    G. Michael Shook

    2005-01-01

    Quantitative analysis of tracer data using moment analysis requires a strict adherence to a set of rules which include data normalization, correction for thermal decay, deconvolution, extrapolation, and integration. If done correctly, the method yields specific information on swept pore volume, flow geometry and fluid velocity, and an understanding of the nature of reservoir boundaries. All calculations required for the interpretation can be done in a spreadsheet. The steps required for moment analysis are reviewed in this paper. Data taken from the literature is used in an example calculation.

  17. Tracer diffusion inside fibrinogen layers

    Science.gov (United States)

    Cieśla, Michał; Gudowska-Nowak, Ewa; Sagués, Francesc; Sokolov, Igor M.

    2014-01-01

    We investigate the obstructed motion of tracer (test) particles in crowded environments by carrying simulations of two-dimensional Gaussian random walk in model fibrinogen monolayers of different orientational ordering. The fibrinogen molecules are significantly anisotropic and therefore they can form structures where orientational ordering, similar to the one observed in nematic liquid crystals, appears. The work focuses on the dependence between level of the orientational order (degree of environmental crowding) of fibrinogen molecules inside a layer and non-Fickian character of the diffusion process of spherical tracer particles moving within the domain. It is shown that in general particles motion is subdiffusive and strongly anisotropic, and its characteristic features significantly change with the orientational order parameter, concentration of fibrinogens, and radius of a diffusing probe.

  18. Tracer diffusion inside fibrinogen layers

    CERN Document Server

    Cieśla, Michał; Sagués, Francesc; Sokolov, Igor M

    2013-01-01

    We investigate the motion of tracer (test) particles in crowded environments by carrying simulations of two-dimensional Gaussian random walk in model fibrinogen monolayers of different orientational ordering. The fibrinogen molecules are significantly anisotropic and therefore they can form structures where orientational ordering, similar to the one observed in nematic liquid crystals, appears. The work focuses on the dependence between level of the orientational order (degree of environmental crowding) of fibrinogen molecules inside a layer and non-Fickian character of the diffusion process of spherical tracer particles moving within the domain. It is shown that in general particles motion is subdiffusive and strongly anisotropic, and its characteristic features significantly change with the orientational order parameter, concentration of fibrinogens and radius of a diffusing probe.

  19. Evaluation of geochemical data acquired from regular grids

    Energy Technology Data Exchange (ETDEWEB)

    Bezvoda, V.; Jelinkova, E.; Segeth, K.

    1986-11-01

    Geochemical data obtained during mineral exploration often are biased by systematic as well as random errors; these may result in failures when usual methods of evaluation are used. This is true particularly in soil surveys carried out in regions where a long history of prospecting and mining activity has occurred and/or where aerial chemical pollution is likely to have occurred. A satisfactory evaluation of geochemical data even in such an unfavorable case requires sampling on a relatively dense grid and utilization of all available knowledge of types of mineralization. The evaluation procedure proposed consists of five consecutive phases: (1) dividing the area of interest into subareas of a relatively homogeneous geological nature; (2) processing by multivariate methods (factor analysis, in particular) without consideration of geographic relations; (3) a preliminary interpretation and search for a geochemical explanation of factors; (4) processing of individual factors in two-dimensional geographic space by directional and frequency linear filtering methods; (5) final interpretation and construction of a geochemical model. The procedure is illustrated by an example from a geochemical exploration survey in the vicinity of Pribram (Middle Bohemia).

  20. Application of natural Ra isotopes and {sup 234}Th as tracers of organic carbon export in Bransfield Strait, Antarctica; Aplicacao dos isotopos naturais de Ra e do Th-234 como tracadores do carbono organico exportado para o Estreito de Bransfield, Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Lucia Helena

    2011-07-01

    The Southern Ocean is the largest of several high-nutrient, low-chlorophyll (HNLC) regions in the world's oceans. This region plays a major role in regulating the global net transfer of carbon dioxide between the ocean and the atmosphere, in part because the annual photosynthetic uptake of CO{sub 2} by phytoplankton and resulting export of particulate organic carbon (POC) to the deep ocean. The element thorium has multiple radioisotopes that have emerged collectively as a powerful set of tracers for particle associated processes in the oceans. Of all the Th isotopes, {sup 234}Th (half-life 24.1 d) has been the focus of increasing attention and application in the past years. The production of {sup 234}Th from {sup 238}U, coupled with the conservative behavior of {sup 238}U in seawater, makes the source of {sup 234}Th easy to characterize. Moreover, the half-life of {sup 234}Th is sufficiently short to make it sensitive to the short-term (e.g. seasonal) changes that occur in the upper water column of the open ocean or in sediments or water column in coastal areas. Because of its very particle reactive behavior, {sup 234}Th is removed from a parcel of water in only two ways, through decay and through particle flux. Therefore, a steady-state 1D activity balance can be used to calculate its flux. Natural Ra isotopes have been also widely used in marine studies to trace water masses and to quantify mixing processes. This work presents results of a collaborative research on organic carbon fluxes distribution in the Bransfield Strait in order to evaluate its influence in the CO{sub 2} drawdown. Macro-nutrients, micro-nutrients and chlorophyll-a distributions were used to examine the pathway sources. Natural radium isotopes were applied as tracers to study the movement of shelf water, while {sup 234}Th was used as a tracer of particle flux in the upper ocean, since POC export via sinking particles is the primary mechanism of carbon sequestration in the Southern Ocean

  1. NOAA and MMS Marine Minerals Geochemical Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Minerals Geochemical Database was created by NGDC as a part of a project to construct a comprehensive computerized bibliography and geochemical database...

  2. Tracer Tests and Field Monitoring of In situ Bioreduction of Cr(VI) Bioreduction at the Hanford 100H Site

    Science.gov (United States)

    Long, P. E.; Newcomer, D. R.; Resch, C. T.; Cantrell, K.; Faybishenko, B.; Hazen, T. C.; Brodie, E.; Joyner, D.; Borglin, S.; Conrad, M.; Tokunaga, T.; Wan, J.; Hubbard, S.; Williams, K. H.; Peterson, J. E.; Firestone, M.; Andersen, G.; Desantis, T.; Hanlon, J.; Willett, A.; Koenigsberg, S.

    2006-05-01

    HRC injection test. Radar tomography combined with seismic measurements appeared to be a valuable field technique in assessing the site lithological heterogeneity and the HRC migration through groundwater. Overall, our results indicate the value of combining frequent in-situ hydrogeological, geochemical and geophysical measurements with microbiological analytical analyses for obtaining data to control biostimulation and long- term natural monitored natural attenuation of Cr in groundwater.

  3. Characterization of eco-friendly fluorescent nanoparticle-doped tracers for environmental sensing

    Energy Technology Data Exchange (ETDEWEB)

    Tauro, Flavia; Rapiti, Emiliano; Al-Sharab, Jafar F. [Polytechnic Institute of New York University, Department of Mechanical and Aerospace Engineering (United States); Ubertini, Lucio [Sapienza University of Rome, Dipartimento di Ingegneria Civile, Edile e Ambientale (Italy); Grimaldi, Salvatore; Porfiri, Maurizio, E-mail: mporfiri@poly.edu [Polytechnic Institute of New York University, Department of Mechanical and Aerospace Engineering (United States)

    2013-09-15

    Particle tracers are extensively used in quantitative flow visualization and environmental sensing. In this paper, we provide a thorough characterization of the novel eco-friendly fluorescent particle tracers formulated in Tauro et al. (AIP Adv 3(3): 032108, 2013). The tracers are synthesized from natural beeswax and are functionalized by encapsulating nontoxic fluorophore nanoparticles in the beads' matrix through an inexpensive thermal procedure. Visibility and durability studies are conducted through a wide array of techniques to investigate the tracers' surface morphological microfeatures, crystal nature and size, chemical composition, fluorophore incorporation into the beeswax matrix, and fluorescence response under severe settings resembling exposure to natural environments. Our findings demonstrate that fluorescent nanoparticles ranging from 1.51 to 3.73 nm are homogeneously distributed in the superficial layer (12 nm) of the tracers. In addition, fluorescence emissions are observed up to 26 days of continuous exposure of the tracers to high energy radiation. To demonstrate the particles' use in environmental flow sensing, a set of proof of concept outdoor tests are conducted, in which image analysis tools are utilized for detecting the fluorescent tracers. Experimental results suggest that fluorescent microparticles deployed in high flow-rate flows (2 m/s) and under direct sunlight can be sensed through commercially available cameras (frame rate set to 30 Hz)

  4. Characterization of eco-friendly fluorescent nanoparticle-doped tracers for environmental sensing

    Science.gov (United States)

    Tauro, Flavia; Rapiti, Emiliano; Al-Sharab, Jafar F.; Ubertini, Lucio; Grimaldi, Salvatore; Porfiri, Maurizio

    2013-09-01

    Particle tracers are extensively used in quantitative flow visualization and environmental sensing. In this paper, we provide a thorough characterization of the novel eco-friendly fluorescent particle tracers formulated in Tauro et al. (AIP Adv 3(3): 032108, 2013). The tracers are synthesized from natural beeswax and are functionalized by encapsulating nontoxic fluorophore nanoparticles in the beads' matrix through an inexpensive thermal procedure. Visibility and durability studies are conducted through a wide array of techniques to investigate the tracers' surface morphological microfeatures, crystal nature and size, chemical composition, fluorophore incorporation into the beeswax matrix, and fluorescence response under severe settings resembling exposure to natural environments. Our findings demonstrate that fluorescent nanoparticles ranging from 1.51 to 3.73 nm are homogeneously distributed in the superficial layer (12 nm) of the tracers. In addition, fluorescence emissions are observed up to 26 days of continuous exposure of the tracers to high energy radiation. To demonstrate the particles' use in environmental flow sensing, a set of proof of concept outdoor tests are conducted, in which image analysis tools are utilized for detecting the fluorescent tracers. Experimental results suggest that fluorescent microparticles deployed in high flow-rate flows (2 m/s) and under direct sunlight can be sensed through commercially available cameras (frame rate set to 30 Hz).

  5. Kriging - a challenge in geochemical mapping

    Science.gov (United States)

    Stojdl, Jiri; Matys Grygar, Tomas; Elznicova, Jitka; Popelka, Jan; Vachova, Tatina; Hosek, Michal

    2017-04-01

    Geochemists can easily provide datasets for contamination mapping thanks to recent advances in geographical information systems (GIS) and portable chemical-analytical instrumentation. Kriging is commonly used to visualise the results of such mapping. It is understandable, as kriging is a well-established method of spatial interpolation. It was created in 1950's for geochemical data processing to estimate the most likely distribution of gold based on samples from a few boreholes. However, kriging is based on the assumption of continuous spatial distribution of numeric data that is not realistic in environmental geochemistry. The use of kriging is correct when the data density is sufficient with respect to heterogeneity of the spatial distribution of the geochemical parameters. However, if anomalous geochemical values are focused in hotspots of which boundaries are insufficiently densely sampled, kriging could provide misleading maps with the real contours of hotspots blurred by data smoothing and levelling out individual (isolated) but relevant anomalous values. The data smoothing can thus it results in underestimation of geochemical extremes, which may in fact be of the greatest importance in mapping projects. In our study we characterised hotspots of contamination by uranium and zinc in the floodplain of the Ploučnice River. The first objective of our study was to compare three methods of sampling: random (based on stochastic generation of sampling points), systematic (square grid) and judgemental sampling (based on judgement stemming from principles of fluvial deposition) as the basis for pollution maps. The first detected problem in production of the maps was the reduction of the smoothing effect of kriging using appropriate function of empirical semivariogram and setting the variation of at microscales smaller than the sampling distances to minimum (the "nugget" parameter of semivariogram). Exact interpolators such as Inverse Distance Weighting (IDW) or Radial

  6. Investigation of radionuclides and anthropic tracer migration in groundwater at the Chernobyl site

    Science.gov (United States)

    Le Gal La Salle, Corinnne; Simonucci, Caroline; Roux, Céline; Bugai, Dmitry; Aquilina, Luc; Fourré, Elise; Jean-Baptiste, Philippe; Labasque, Thierry; Michelot, Jean-Luc; Fifield, Keith; Team Aster Team; Van Meir, Nathalie; Kashparov, Valeriy; Diez, Olivier; Bassot, Sylvain; Lancelot, Joel

    2013-04-01

    , associated with U-Zr matrix fuel particles [5] and/or that migration of U is limited due to redox processes and/or microbial activity. The above described experience of post-Chernobyl studies shows that a combined analysis of radionuclides, natural and anthropogenic tracers provides an efficient research tool to better understand and quantify contaminant transport processes in the geo-sphere. Similar approaches can be applied to the study transport of RN in the subsurface, issued from both, diffuse (contaminated watersheds) and point (damaged NPP and fuel storage units) radioactive sources produced by the Fukushima accident. References [1] Dzhepo S. P., Skalskyy A., 2002, In Chernobyl disaster and groundwater, Shestopalov, V., Ed. A.A. Balkema: Lisse, pp 25-70. [2] Dewiere L., Bugai D. et al., 2004, J. Environ. Radioactiv., 74, (1-3), 139-150. [3] Van Meir N., Bugaï, et al., 2009, in: Oughton, D.H., Kashparov, V. (Eds.), Radioactive Particles in the Environment. Springer Science+Business Media B.V., pp.197-208. [4] Le Gal La Salle C., Aquilina L., et al., 2012, Appl. Geochem., 27 1304-1319. [5] Kashparov V.A., Ahamdach N., et. al., 2004, J. Environ. Radioactiv., 72, 335-353.

  7. The Transient Tracers in the Ocean (TTO) program: The North Atlantic Study, 1981; The Tropical Atlantic Study, 1983

    Science.gov (United States)

    Brewer, Peter G.; Sarmiento, Jorge L.; Smethie, William M.

    1985-01-01

    The scientific papers here collected result from the Transient Tracers in the Ocean (TTO) program. The two parts of this major geochemical and physical oceanographie expedition took place in the North Atlantic Ocean in 1981 and in the Tropical Atlantic in 1983 on the research vessel Knorr of the Woods Hole Oceanographie Institution. The expeditions, sponsored by the National Science Foundation and the U.S. Department of Energy (North Atlantic only), were designed to observe the passage of man-made geochemical tracers into the interior of the ocean. The foundations for such an experiment were laid in the 1972-1978 GEOSECS program. Here, for the first time, a systematic survey revealed the penetration into the thermocline and deep ocean of the products of man's military/industrial activities, principally tritium and carbon-14 resulting from atmospheric testing of nuclear weapons, which terminated with the nuclear test ban treaty in 1962.

  8. Tracer tests in geothermal resource management

    Directory of Open Access Journals (Sweden)

    Axelsson G.

    2013-05-01

    Full Text Available Geothermal reinjection involves injecting energy-depleted fluid back into geothermal systems, providing an effective mode of waste-water disposal as well as supplementary fluid recharge. Cooling of production boreholes is one of the main disadvantages associated with reinjection, however. Tracer testing is an important tool for reinjection studies because tracer tests actually have a predictive power since tracer transport is orders of magnitude faster than cold-front advancement around reinjection boreholes. A simple and efficient method of tracer test interpretation, assuming specific flow channels connecting reinjection and production boreholes, is available. It simulates tracer return profiles and estimates properties of the flow channels, which are consequently used for predicting the production borehole cooling. Numerous examples are available worldwide on the successful application of tracer tests in geothermal management, many involving the application of this interpretation technique. Tracer tests are also used for general subsurface hydrological studies in geothermal systems and for flow rate measurements in two-phase geothermal pipelines. The tracers most commonly used in geothermal applications are fluorescent dyes, chemical substances and radioactive isotopes. New temperature-resistant tracers have also been introduced and high-tech tracers are being considered.

  9. Dual signature tracer: A new tool for soil management and research.

    Science.gov (United States)

    Poleykett, Jack; Quinton, John; Armstrong, Alona; Maher, Barbara; Black, Kevin

    2015-04-01

    The significant detrimental effects that occur, both on and off site due to the transport of soil are well documented. Now more than ever, it is vital to understand the pathways, processes and fate of transported sediments, to underpin environmental strategy and develop robust forecast models. Researchers have employed a broad range of materials and techniques to trace the movement of soil through space and time. However, three primary challenges still remain: 1) to develop a tracer that has the same or similar hydraulic characteristics as soil: 2) to develop a tracer able to replicate the broad and variable particle size distribution of soils; and: 3) to develop a tracing methodology that increases the volume, and quality of data collected from the field. This study approaches these challenges using a unique 'dual signature' tracer comprising natural mineral material directly coated with a fluorescent dye pigment and loaded during coating with a naturally occurring magnetic mineral oxide creating a tracer with both fluorescent properties and para-magnetic character. An assessment of the effectiveness of the tracer as a tracer of soil was conducted at the soil box and plot scale under controlled rainfall conditions, to: 1) examine the behaviour of the tracer, and: 2) to assess the efficiency of the different tools available to monitor the tracer post- deployment. At the plot scale, a unique site specific tracer was developed to match the hydraulic characteristics (particle size distribution and specific gravity), of the native soil enabling the source-sink relationship, transport pathways and transport rate through the environment to be investigated. Spatial mapping of the tracer distribution within each plot was also conducted using photography and Ultra Violet (UV) illumination. The results of this study provide the basis for the development of a unique soil tracing methodology, which can be applied to investigate soil transport processes, at a range of scales in

  10. Geochemical atlas of Radoviš and the environs and the distribution of heavy metals in the air

    OpenAIRE

    Stafilov, Trajče; Balabanova, Biljana; Sajn, Robert; Baceva, Katerina; Boev, Blazo

    2010-01-01

    Introduction; Geographic description; Geological description; Material and methods: Sampling, Global positioning system, Sample preparation, Instrumentation, Reliability of chemical analysis; Data processing and drawing maps: Statistical analysis, Data mapping; Bio-monitoring with moss samples: Anthropogenic distribution of chemical elements; Geochemical association Al-As-Cd-Cu-Fe-Pb-Zn; Natural distribution of elements: Geochemical association Cr-Ni-Sr; Geochemical association Ba-K-Na; Monit...

  11. Matching tracer selection to georeservoir typology - A note on geothermal reservoir classification

    Science.gov (United States)

    Ghergut, Julia; Behrens, Horst; Licha, Tobias; Sauter, Martin

    2013-04-01

    Thermal-lifetime prediction is a traditional endeavor of inter-well tracer tests conducted in geothermal reservoirs. Early tracer test signals (detectable within the first few years of operation) are expected to correlate with late-time production temperature drop (so-called 'thermal breakthrough', supposed to not occur before some decades of operation) of a geothermal reservoir. Whenever a geothermal reservoir can be described as a single-fracture system, its thermal lifetime will, ideally, be determined by two parameters, whose inversion from conservative-tracer test signals is straightforward and non-ambiguous (provided that the tracer tests, and their interpretation, are performed in accordance to the rules of the art). However, as soon as just few more fractures are considered, this clear-cut correlation is broken. A given geothermal reservoir can simultaneously exhibit a single-fracture behavior, in terms of heat transport, and a multiple-fracture behavior, in terms of solute tracer transport (or vice-versa), whose effective values of fracture apertures, spacings, and porosities are essentially uncorrelated between heat and solute tracers. Solute transport parameters derived from conservative-tracer tests will no longer characterize the heat transport processes (and thus temperature evolutions) taking place in the same reservoir. Parameters determining its thermal lifetime will remain invisible to conservative tracers in inter-well tests. Non-conservative tracers, in particular sorptive and thermo-sensitive compounds, can be used to overcome this gap between heat and tracer transport. However, significant differences exist, w. r. to tracer functionality, between different geothermal systems: (I) hot natural aquifers (with predominantly 'porous media' character), (II) aquifer-based EGS, (III) petrothermally-based EGS, (IV) naturally-fractured systems. Conservative tracers are indispensable to characterizing any of (I) - (IV), but their residence time

  12. An uncertainty inclusive un-mixing model to identify tracer non-conservativeness

    Science.gov (United States)

    Sherriff, Sophie; Rowan, John; Franks, Stewart; Fenton, Owen; Jordan, Phil; hUallacháin, Daire Ó.

    2015-04-01

    Sediment fingerprinting is being increasingly recognised as an essential tool for catchment soil and water management. Selected physico-chemical properties (tracers) of soils and river sediments are used in a statistically-based 'un-mixing' model to apportion sediment delivered to the catchment outlet (target) to its upstream sediment sources. Development of uncertainty-inclusive approaches, taking into account uncertainties in the sampling, measurement and statistical un-mixing, are improving the robustness of results. However, methodological challenges remain including issues of particle size and organic matter selectivity and non-conservative behaviour of tracers - relating to biogeochemical transformations along the transport pathway. This study builds on our earlier uncertainty-inclusive approach (FR2000) to detect and assess the impact of tracer non-conservativeness using synthetic data before applying these lessons to new field data from Ireland. Un-mixing was conducted on 'pristine' and 'corrupted' synthetic datasets containing three to fifty tracers (in the corrupted dataset one target tracer value was manually corrupted to replicate non-conservative behaviour). Additionally, a smaller corrupted dataset was un-mixed using a permutation version of the algorithm. Field data was collected in an 11 km2 river catchment in Ireland. Source samples were collected from topsoils, subsoils, channel banks, open field drains, damaged road verges and farm tracks. Target samples were collected using time integrated suspended sediment samplers at the catchment outlet at 6-12 week intervals from July 2012 to June 2013. Samples were dried (thermal remanence, and geochemical elements Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn (following microwave-assisted acid digestion). Discriminant analysis was used to reduce the number of tracer numbers before un-mixing. Tracer non-conservativeness results showed that the predictions of median source contributions were negatively affected whereas

  13. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  14. TRAC, a collaborative computer tool for tracer-test interpretation

    Science.gov (United States)

    Gutierrez, A.; Klinka, T.; Thiéry, D.; Buscarlet, E.; Binet, S.; Jozja, N.; Défarge, C.; Leclerc, B.; Fécamp, C.; Ahumada, Y.; Elsass, J.

    2013-05-01

    Artificial tracer tests are widely used by consulting engineers for demonstrating water circulation, proving the existence of leakage, or estimating groundwater velocity. However, the interpretation of such tests is often very basic, with the result that decision makers and professionals commonly face unreliable results through hasty and empirical interpretation. There is thus an increasing need for a reliable interpretation tool, compatible with the latest operating systems and available in several languages. BRGM, the French Geological Survey, has developed a project together with hydrogeologists from various other organizations to build software assembling several analytical solutions in order to comply with various field contexts. This computer program, called TRAC, is very light and simple, allowing the user to add his own analytical solution if the formula is not yet included. It aims at collaborative improvement by sharing the tool and the solutions. TRAC can be used for interpreting data recovered from a tracer test as well as for simulating the transport of a tracer in the saturated zone (for the time being). Calibration of a site operation is based on considering the hydrodynamic and hydrodispersive features of groundwater flow as well as the amount, nature and injection mode of the artificial tracer. The software is available in French, English and Spanish, and the latest version can be downloaded from the web site http://trac.brgm.fr">http://trac.brgm.fr.

  15. Tracer tests in geothermal resource management

    OpenAIRE

    Axelsson G.

    2013-01-01

    Geothermal reinjection involves injecting energy-depleted fluid back into geothermal systems, providing an effective mode of waste-water disposal as well as supplementary fluid recharge. Cooling of production boreholes is one of the main disadvantages associated with reinjection, however. Tracer testing is an important tool for reinjection studies because tracer tests actually have a predictive power since tracer transport is orders of magnitude faster than cold-front advancement around reinj...

  16. Study on Radioecology and Tracer of Iodine-129

    Energy Technology Data Exchange (ETDEWEB)

    Xiaolin, Hou [Riso National Laboratory, NUK, DK, Roskilde (Denmark)

    2004-07-01

    Iodine-129 (15.7 Ma) is a naturally occurring radioisotope of iodine. The ratio of {sup 129}I/{sup 127}I was estimated to be {approx} 10{sup -12} in the ocean and 10{sup -11} in the territorial environment in pre-nuclear era, releases from nuclear weapon tests have increased this ratio to {approx} 10{sup -10}. However, a large amount of iodine-129 was released from various nuclear facilities, and the greatest releases of {sup 129}I are from two European reprocessing plants, especially in recent years. By 1998, 2600 Kg and 220 Kg {sup 129}I have been discharged to the marine environment and atmosphere from La Hague (France) and Sellafield reprocessing plants, respectively. This amount is tens times larger than the total {sup 129}I inventory in the pre-nuclear ocean and weapon test releases. Although there is no significant radiation risk for the human health at present level of {sup 129}I, the continuously increasing production and release of {sup 129}I make the accumulation of {sup 129}I in the environment, immigration, cycle and long term radioecological risk should be give more attention due to its long half-life, high accumulation in human thyroid and high mobility. Iodine is a conservative element in the ocean, the large amount of iodine-129 discharged to the marine system can therefore be used as a oceanographic tracer to study the physical dispersion, mixing and circulative processes of water mass in the ocean. In Riso national laboratory, a radiochemical neutron activation analysis method was developed, using this method the radioecology and tracer of iodine-129 was studied. Some representative works are presented below. (1) Evaluation of radiation exposure of humans to iodine-129. The human and animal thyroids collected from different places, such as Tianjin in China, Gemol in Belarus, Ribe in Denmark, human urine in Denmark, seafood in China were analysed for iodine-129 concentration and {sup 129}I/{sup 127}I ratio, the exposure level were compared with

  17. Advances in geochemical research on nanometer materials

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Important advances have been made in the field of geochemistry since nanometer science and technology were introduced into the field of geoscience. The nanometer particulates have been discovered in naturally-occurring ore deposits, volcano-eruptive materials and geo-gases, and a more detailed exploration of the metallogenic mechanism of endogenic metallic ore deposits has been conducted. It is considered that some ore-forming metals may transport in the form of native particulates. Because they have very strong capabilities of adsorption, adsorption is always regarded as an important mechanism of metallogenesis under supergenic and low temperature conditions.Therefore, a new technology of ore exploration has also been developed. This paper attempts to review the new advances in geochemical research on nanometer materials, as well as its perspectivess.

  18. Tracer-Test Planning Using the Efficient Hydrologic Tracer-Test Design (Ehtd) Program (2003)

    Science.gov (United States)

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test ...

  19. The Geochemical Society(GS)

    Institute of Scientific and Technical Information of China (English)

    Seth M.Davis

    2007-01-01

    @@ Mission The Geochemical Society is an international nonprofit organization for scientists involved in the practice,study and teaching of geochemistry.0ur principal roles are to understand and meet the needs of our members so as to provide them with programs and services that will help them be better geochemists;to empower geochemists through information,education,relationships and resources that will enrich their professional development and careers;and to advance the thought and application of geochemistry.

  20. Mapping the Mariana Seismogenic Zone Through the Measurement of Geochemical Tracers in Serpentinite Seamounts

    Science.gov (United States)

    Hulme, S. M.; Wheat, C. G.; Mottl, M. J.; Fryer, P.

    2003-12-01

    The Mariana forearc contains tens of seamounts up to 2 km high and 20-50 km in diameter. These seamounts were formed by serpentinite mud volcanism, sometimes in combination with uplift of serpentinized forearc mantle blocks, in which fluids driven off of the subducting slab infiltrated the overlying mantle and serpentinized the harzburgite and dunite rocks creating a density imbalance within the mantle. The resulting fluid-rock matrix flows along faults and exposes mantle-sourced serpentinite muds, blueschist facies metamorphosed mafic clasts, and slab-sourced fluids at the seafloor. The protrusion of these materials allows direct observation of active subduction zone components that are elsewhere buried beneath kilometers of rock and sediment. A multi-disciplinary survey of the Mariana Forearc was conducted in the spring of 2003 to study the biogeochemical properties of this mud volcanism. Seven different seamounts were sampled using shipboard and subsea coring techniques employing RV Thomas G. Thompson and ROV Jason II, respectively. Pore waters were extracted from these sediment cores and analyzed for several chemical constituents at sea. The measured values were consistent with preliminary work from 1997. Systematic trends in chemical composition of these high pH fluids (up to 12.3) are observed with distance from the trench (proxy for the depth to slab). These trends include low alkalinity and high Ca near the trench (e.g., Blue Moon Seamount; 0.26 mmol alkalinity/kg and 55 mmol Ca/kg), and high alkalinity and low Ca further from the trench (e.g., Big Blue Seamount; 69 mmol alkalinity/kg and 0.14 mmol Ca/kg) consistent with carbonate dissolution at the top of the plate between depths of 17 km and 22 km. Here we report results from trace element analyses that similarly show trends across the forearc region. For example, fluids upwelling at Baby Blue Seamount have; 58 μ mol Sr/kg, 31 μ mol Li/kg, 1.4 μ mol Rb/kg, 10 nmol Cs/kg, 0.2 μ mol Ba/kg, 0.1 μ mol Mo/kg, 0.6 nmol U/kg, and 5 nmol Y/kg. In contrast, fluids from Big Blue Seamount, only 23 km away, have; 10 μ mol Sr/kg, 0.7 μ mol Li/kg, 6 μ mol Rb/kg, 0.2 μ mol Cs/kg, 60 nmol Ba/kg, 0.1 μ mol Mo/kg, 0.2 μ mol U/kg, and 0.1 nmol Y/kg.Trace element analyses for a host of chemical species and for each of the sampled seamounts offer insight into the conditions and interactions currently occurring within the Mariana seismogenic zone.

  1. Stable sulfur and oxygen isotopes as geochemical tracers of sulfate in karst waters

    Science.gov (United States)

    Sun, Jing; Kobayashi, Tatsuaki; Strosnider, William H. J.; Wu, Pan

    2017-08-01

    Karst water resources, which are extremely sensitive to mining activities, are critical for the support of human societies and ecological systems in many regions worldwide. In order to determine the sources and fate of dissolved sulfate in low-pH karst waters, hydrochemical variations of karst waters with and without acid mine drainage (AMD) impacts were investigated along with stable isotope dynamics. As expected, hydrochemical characteristics and isotopic compositions of the AMD and AMD-downstream water (ADW) were dramatically different from that of the non-AMD-impacted water (NAW). The sources of sulfur isotopes in sulfate were predominantly pyrite oxidation for the AMD and ADW, and atmospheric deposition for the NAW. Based on the general isotope-balance model, the relative proportions of sulfate oxygen derived from water and air were calculated. The mean proportion of sulfate oxygen derived from water in ADW was roughly double that of AMD. This suggests that the sulfate associated with AMD is predominantly influenced by aerobic pyrite oxidation, while that of ADW is likely affected by the dissolution of pyrite under anaerobic conditions in reservoir sediment. This observation was coincident with the noted variations of hydrochemical characteristics and was supported by principal component analysis. These results provide a better understanding of how stable isotopes of sulfate and water can be used to track mining contamination in karst aquifers, which could benefit remediation planning for these distinctive systems.

  2. Movements of diadromous fish in large unregulated tropical rivers inferred from geochemical tracers.

    Science.gov (United States)

    Walther, Benjamin D; Dempster, Tim; Letnic, Mike; McCulloch, Malcolm T

    2011-04-06

    Patterns of migration and habitat use in diadromous fishes can be highly variable among individuals. Most investigations into diadromous movement patterns have been restricted to populations in regulated rivers, and little information exists for those in unregulated catchments. We quantified movements of migratory barramundi Lates calcarifer (Bloch) in two large unregulated rivers in northern Australia using both elemental (Sr/Ba) and isotope ((87)Sr/(86)Sr) ratios in aragonitic ear stones, or otoliths. Chemical life history profiles indicated significant individual variation in habitat use, particularly among chemically distinct freshwater habitats within a catchment. A global zoning algorithm was used to quantify distinct changes in chemical signatures across profiles. This algorithm identified between 2 and 6 distinct chemical habitats in individual profiles, indicating variable movement among habitats. Profiles of (87)Sr/(86)Sr ratios were notably distinct among individuals, with highly radiogenic values recorded in some otoliths. This variation suggested that fish made full use of habitats across the entire catchment basin. Our results show that unrestricted movement among freshwater habitats is an important component of diadromous life histories for populations in unregulated systems.

  3. Tracers for Characterizing Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  4. Tracers for Characterizing Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  5. Geochemical Investigations of Groundwater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)

    2006-05-15

    The report describes geochemical parameters and methods that provide information about the hydrodynamic stability of groundwaters in low permeability fractured rocks that are potential hosts for radioactive waste repositories. Hydrodynamic stability describes the propensity for changes in groundwater flows over long timescales, in terms of flow rates and flow directions. Hydrodynamic changes may also cause changes in water compositions, but the related issue of geochemical stability of a potential repository host rock system is outside the scope of this report. The main approaches to assessing groundwater stability are numerical modelling, measurement and interpretation of geochemical indicators in groundwater compositions, and analyses and interpretations of secondary minerals and fluid inclusions in these minerals. This report covers the latter two topics, with emphasis on geochemical indicators. The extent to which palaeohydrogeology and geochemical stability indicators have been used in past safety cases is reviewed. It has been very variable, both in terms of the scenarios considered, the stability indicators considered and the extent to which the information was explicitly or implicitly used in assessing FEPs and scenarios in the safety cases. Geochemical indicators of hydrodynamic stability provide various categories of information that are of hydrogeological relevance. Information about groundwater mixing, flows and water sources is potentially provided by the total salinity of groundwaters, their contents of specific non-reactive solutes (principally chloride) and possibly of other solutes, the stable isotopic ratio of water, and certain characteristics of secondary minerals and fluid inclusions. Information pertaining directly to groundwater ages and the timing of water and solute movements is provided by isotopic systems including tritium, carbon-14, chlorine-36, stable oxygen and hydrogen isotopes, uranium isotopes and dissolved mobile gases in

  6. Numerical flow models and their calibration using tracer based ages: Chapter 10

    Science.gov (United States)

    Sanford, W.

    2013-01-01

    Any estimate of ‘age’ of a groundwater sample based on environmental tracers requires some form of geochemical model to interpret the tracer chemistry (chapter 3) and is, therefore, referred to in this chapter as a tracer model age. the tracer model age of a groundwater sample can be useful for obtaining information on the residence time and replenishment rate of an aquifer system, but that type of data is most useful when it can be incorporated with all other information that is known about the groundwater system under study. groundwater fl ow models are constructed of aquifer systems because they are usually the best way of incorporating all of the known information about the system in the context of a mathematical framework that constrains the model to follow the known laws of physics and chemistry as they apply to groundwater flow and transport. It is important that the purpose or objective of the study be identified first before choosing the type and complexity of the model to be constructed, and to make sure such a model is necessary. The purpose of a modelling study is most often to characterize the system within a numerical framework, such that the hydrological responses of the system can be tested under potential stresses that might be imposed given future development scenarios. As this manual discusses dating as it applies to old groundwater, most readers are likely to be interested in studying regional groundwater flow systems and their water resource potential.

  7. Geochemical barriers for environment protection and recovery of nonferrous metals.

    Science.gov (United States)

    Chanturiya, Valentine; Masloboev, Vladimir; Makarov, Dmitriy; Nesterov, Dmitriy; Bajurova, Julia; Svetlov, Anton; Men'shikov, Yuriy

    2014-01-01

    A study of natural minerals, ore tailings and their products as materials for artificial geochemical barriers is presented. In particular, it focuses on interaction between calcite and dolomite and sulfate solutions containing nickel, copper and iron under static conditions. Calcite of -0.1 mm fraction has been shown to perform well as a barrier when added to water phases of tailing dumps and natural reservoirs. Experiments under dynamic conditions have revealed a high potential of thermally activated copper-nickel tailings as barriers. After a 500-day precipitating period on a geochemical barrier, the contents of nickel and copper in ore dressing tailings were found to increase 12- and 28-fold, respectively. An effective sorbent of copper, iron and nickel ions is a brucite-based product of hydrochloric acid treatment of vermiculite ore tailings. Its sorption capacity can be essentially increased through thermal activation.

  8. The Accurate Particle Tracer Code

    CERN Document Server

    Wang, Yulei; Qin, Hong; Yu, Zhi

    2016-01-01

    The Accurate Particle Tracer (APT) code is designed for large-scale particle simulations on dynamical systems. Based on a large variety of advanced geometric algorithms, APT possesses long-term numerical accuracy and stability, which are critical for solving multi-scale and non-linear problems. Under the well-designed integrated and modularized framework, APT serves as a universal platform for researchers from different fields, such as plasma physics, accelerator physics, space science, fusion energy research, computational mathematics, software engineering, and high-performance computation. The APT code consists of seven main modules, including the I/O module, the initialization module, the particle pusher module, the parallelization module, the field configuration module, the external force-field module, and the extendible module. The I/O module, supported by Lua and Hdf5 projects, provides a user-friendly interface for both numerical simulation and data analysis. A series of new geometric numerical methods...

  9. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra. In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  10. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  11. The Copenhagen tracer experiments: Reporting of measurements

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Lyck, E.

    2002-01-01

    buoyancy from a tower at a height of 115 meters and then collected 2-3 meters above ground-level at positions in up to three crosswind arcs of tracer sampling units, positioned 2-6 km from the point of release. Three consecutive 20 min averaged tracer concentrations were measured, allowing for a total...

  12. Effect of tracer buoyancy on tracer experiments conducted in fractured crystalline bedrock

    Science.gov (United States)

    Becker, Matthew W.

    2003-02-01

    Tracer buoyancy has been shown to influence breakthrough from two-well tracer experiments conducted in porous media. Two-well tracer experiments are presented from fractured crystalline bedrock, in which the specific gravity of the tracer injectate varied from 1.0002 to 1.0133. Under the forced hydraulic conditions imposed, no difference in breakthrough was noted for the three experiments. These results show that even relatively dense tracer injectate solutions may have an insignificant effect on breakthrough when imposed gradients are sufficiently large.

  13. The Art of Tomographic Tracer Tests

    Science.gov (United States)

    Cirpka, O. A.; Leven, C.; Doro, K. O.; Sanchez-Leon, E. E.

    2015-12-01

    In tracer tomography several tracer tests are performed within an aquifer and breakthrough curves are observed at multiple observation points. In the analysis, hydraulic conductivity is estimated as spatially variable, 3-D field subject to some smoothness constraint. Coupled flow and transport models using this conductivity fields are requested to meet observed tracer data. The approach can be combined with hydraulic tomography.We have performed hydraulic-tomography and tracer-tomography tests using heat and fluorescein as tracers at a field site close to Tübingen, Germany. The aquifer consists of 8-9m alluvials sands and gravels overlain by 1-2m alluvial fines. The hydraulic setup consists of a forced flow field between an injection/extraction well couple, embedded in the forced flow field of another well couple. By turning injection to extraction wells, and vice versa, two different flow fields were considered. Injection wells were separated into several sections by packers, and water was injected into each section proportional to its transmissivity. The water injected into one of the sections contained the tracer. Multi-level observation wells were equiped with thermometers (for heat-tracer tests), on-line fluoremeters (for teh dye tracers), and pressure transducers. Processing of the breakthrough curves included data cleaning, non-parametric deconvolution, and calculation of temperal moments of the estimated transfer functions.The joint inversion of hydraulic-head measurements and temporal moments of heat-tracer transfer functions was done by the quasi-linear geostatistical approach on a computing cluster. As alternative, we directly invert the time series (without temporal moments) by Ensemble-Kalman filtering.The high diffusion coefficient of temperature diminishes the penetration of the heat-tracer into the aquifer, which can partially be compensated by reverting the flow field and repeating the tracer tests. In tests with fluorscent tracers the signal

  14. Composition of natural gas and crude oil produced from 14 wells in the Lower Silurian "Clinton" Sandstone and Medina Group Sandstones, northeastern Ohio and northwestern Pennsylvania: Chapter G.6 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Burruss, Robert A.; Ryder, Robert T.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    The geochemical processes that control the distribution of hydrocarbons in the regional accumulation of natural gas and crude oil in reservoirs of Early Silurian age in the central Appalachian basin are not well understood. Gas and oil samples from 14 wells along a down-dip transect through the accumulation in northeastern Ohio and northwestern Pennsylvania were analyzed for molecular and stable isotopic compositions to look for evidence of hydrocarbon source, thermal maturation, migration, and alteration parameters. The correlation of carbon and hydrogen stable isotopic composition of methane with thermal maturation indicates that the deepest gases are more thermally mature than independent estimates of thermal maturity of the reservoir horizon based on the conodont alteration index. This correlation indicates that the natural gas charge in the deepest parts of the regional accumulation sampled in this study originated in deeper parts of the Appalachian basin and migrated into place. Other processes, including mixing and late-stage alteration of hydrocarbons, may also impact the observed compositions of natural gases and crude oils.

  15. Composition of natural gas and crude oil produced from 14 wells in the Lower Silurian "Clinton" Sandstone and Medina Group Sandstones, northeastern Ohio and northwestern Pennsylvania: Chapter G.6 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Burruss, Robert A.; Ryder, Robert T.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    The geochemical processes that control the distribution of hydrocarbons in the regional accumulation of natural gas and crude oil in reservoirs of Early Silurian age in the central Appalachian basin are not well understood. Gas and oil samples from 14 wells along a down-dip transect through the accumulation in northeastern Ohio and northwestern Pennsylvania were analyzed for molecular and stable isotopic compositions to look for evidence of hydrocarbon source, thermal maturation, migration, and alteration parameters. The correlation of carbon and hydrogen stable isotopic composition of methane with thermal maturation indicates that the deepest gases are more thermally mature than independent estimates of thermal maturity of the reservoir horizon based on the conodont alteration index. This correlation indicates that the natural gas charge in the deepest parts of the regional accumulation sampled in this study originated in deeper parts of the Appalachian basin and migrated into place. Other processes, including mixing and late-stage alteration of hydrocarbons, may also impact the observed compositions of natural gases and crude oils.

  16. Radon as tracer to identify discharge sections at Juatuba basin

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, Claudio Jose; Ferreira, Vinicius Verna Magalhaes; Fonseca, Raquel Luisa Mageste; Rocha, Zildete; Moreira, Rubens Martins; Lemos, Nayron Cosme; Menezes, Angela de Barros Correia, E-mail: vvmf@cdtn.br, E-mail: rlmf@cdtn.br, E-mail: cjc@cdtn.br, E-mail: rochaz@cdtn.br, E-mail: rubens@cdtn.br, E-mail: menezes@cdtn.br, E-mail: lemosnc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Santos, Talita Oliveira, E-mail: talitaolsantos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Departamento de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2015-07-01

    The use of natural tracers in hydrological studies is a very useful tool, being applied in several studies. One of these tracers is the radon, {sup 222}Rn, noble gas derived from natural sources, been found in all underground waters, as a product of radioactive decay of the {sup 226}Ra. This gas can be found in the air, water, rocks or soil. In this paper, the {sup 222}Rn detection in surface water was used as tracer in order to identify aquifer discharge sections in surface water at the Fundao stream, which belongs to the Juatuba river basin, through the second semester of 2014 and the first semester of 2015, in three sampling campaigns. The {sup 222}Rn measurements at Fundao stream were carried out using the equipment RAD 7. The results showed that {sup 222}Rn is present in some sections of the water course suggesting that there is a connection between groundwater and surface water. It also justifies the variation in the water level in the stream, recorded by a fluviometric station. (author)

  17. Environmental radionuclides tracers and timers of terrestrial processes

    CERN Document Server

    Froehlich, Klaus

    2009-01-01

    The book presents a state-of-the-art summary of knowledge on the use of radionuclides to study processes and systems in the continental part of the Earth's environment. It is conceived as a companion to the two volumes of this series, which deal with isotopes as tracers in the marine environment (Livingston, Marine Radioactivity) and with the radioecology of natural and man-made terrestrial systems (Shaw, Radioactivity in Terrestrial Ecosystems). Although the book focuses on natural and anthropogenic radionuclides (radioactive isotopes), it also refers to stable environmental isotopes, which i

  18. Alaska Geochemical Database (AGDB) - Geochemical Data for Rock, Sediment, Soil, Mineral, and Concentrate Sample Media

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping,...

  19. A Galaxy-Halo Model for Multiple Cosmological Tracers

    CERN Document Server

    Bull, Philip

    2016-01-01

    The information extracted from large galaxy surveys with the likes of DES, DESI, Euclid, LSST, SKA, and WFIRST will be greatly enhanced if the resultant galaxy catalogues can be cross-correlated with one another. Predicting the nature of the information gain, and developing the tools to realise it, depends on establishing a consistent model of how the galaxies detected by each survey trace the same underlying matter distribution. Existing analytic methods, such as halo occupation distribution (HOD) modelling, are not well-suited for this task, and can suffer from ambiguities and tuning issues when applied to multiple tracers. We construct a simple alternative that provides a common model for the connection between galaxies and dark matter halos across a wide range of wavelengths (and thus tracer populations). This is based on a chain of parametrised statistical distributions that model the connection between (a) halo mass and bulk physical properties of galaxies, such as star-formation rate; and (b) those sam...

  20. Geochemical proxies for understanding paleoceanography

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.

    secondary end member chlorite (K2 O/Al2 O3=0). In addition, other tracers such as K/Ti and Ca/Ti, along with rare-earth element fractionation indices have been used clearly to distinguish the HHC derived sediments from the normal pelagic clays... The TiO 2/Al203 ratio in sediments has been tentatively used to deduce past changes in shallow-water stream energies. This approach relies on the fact that in crustal rocks titanium typically exists in insoluble, heavy minerals such as ilmenite, rutile...

  1. Validation of the WATEQ4 geochemical model for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.

    1983-09-01

    As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite (UO/sub 2/(OH)/sub 2/ . H/sub 2/O), UO/sub 2/(OH)/sub 2/, and rutherfordine ((UO/sub 2/CO/sub 3/) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions.

  2. Geochemical and isotopic investigations on the thermal and mineral underground waters from the Republic of Moldova

    Science.gov (United States)

    Nisi, Barbara; Bogdevich, Oleg; Vaselli, Orlando; Nicoara, Igor; Tassi, Franco; Culighin, Elena; Mogorici, Cristina; Jeleapov, Victor; Mussi, Mario

    2017-04-01

    Republic of Moldova (RM) has a large spectrum of underground mineral waters (16 reservoirs) of eight principal aquifers, most of which affected by contaminants originated by natural sources and anthropogenic activities. Inorganic natural tracers and stable isotopes are useful tools to fingerprint the water source and solutes, respectively. The aim of this investigation was to determine the geochemical and isotopic features of the most important thermo- and mineral waters from RM to trace their flow pathways and evaluate the presence of deep fluid sources discharging from fault systems, developed in response to the structural setting of the area. To the best of our knowledge, no systematic geochemical investigations were previously carried out in this area. RM has an area of 33,840 km2 and lies within the East European Precambrian Platform, two structural and/or stratigraphic layers, which are distinguishable in basement and sedimentary cover in the northern and central part of country. The basement rocks include granites, gneisses and gabbros. The sedimentary cover, overlying the crystalline basement, is almost undeformed and consists of Upper Proterozoic, Mesozoic and Cenozoic rocks. The geological structure is like a matrix formed from different layers of rocks consisting of permeable and impermeable strata. The deep aquifers are situated down to 1,000 m depth from the bottom to the top: Vendian (Ediocariam) and crystalline basement rocks, Silurian crystalline limestone, Cretaceous limestone, Baden-Sarmatian limestone and clay-sand deposits, middle Sarmatian limestone and clay-sand layers. Other younger aquifers were not investigated. In this framework, 54 samples from the most important underground reservoirs of RM were collected and analyzed for major, trace species and dissolved gases. An inventory of isotopic (18O/16O and 2H/1H ratios in water and 13C/12C in dissolved CO2) features (including tritium units in selected samples) was also provided. By a

  3. Three-Dimensional Bayesian Geostatistical Aquifer Characterization at the Hanford 300 Area using Tracer Test Data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xingyuan; Murakami, Haruko; Hahn, Melanie S.; Hammond, Glenn E.; Rockhold, Mark L.; Zachara, John M.; Rubin, Yoram

    2012-06-01

    Tracer testing under natural or forced gradient flow holds the potential to provide useful information for characterizing subsurface properties, through monitoring, modeling and interpretation of the tracer plume migration in an aquifer. Non-reactive tracer experiments were conducted at the Hanford 300 Area, along with constant-rate injection tests and electromagnetic borehole flowmeter (EBF) profiling. A Bayesian data assimilation technique, the method of anchored distributions (MAD) [Rubin et al., 2010], was applied to assimilate the experimental tracer test data with the other types of data and to infer the three-dimensional heterogeneous structure of the hydraulic conductivity in the saturated zone of the Hanford formation. In this study, the Bayesian prior information on the underlying random hydraulic conductivity field was obtained from previous field characterization efforts using the constant-rate injection tests and the EBF data. The posterior distribution of the conductivity field was obtained by further conditioning the field on the temporal moments of tracer breakthrough curves at various observation wells. MAD was implemented with the massively-parallel three-dimensional flow and transport code PFLOTRAN to cope with the highly transient flow boundary conditions at the site and to meet the computational demands of MAD. A synthetic study proved that the proposed method could effectively invert tracer test data to capture the essential spatial heterogeneity of the three-dimensional hydraulic conductivity field. Application of MAD to actual field data shows that the hydrogeological model, when conditioned on the tracer test data, can reproduce the tracer transport behavior better than the field characterized without the tracer test data. This study successfully demonstrates that MAD can sequentially assimilate multi-scale multi-type field data through a consistent Bayesian framework.

  4. Using Tracer Technology to Characterize Contaminated Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Maresca, Joseph, W., Jr., Ph.D.; Bratton, Wesley, L., Ph.D., P.E.; Dickerson, Wilhelmina; Hales, Rochelle

    2005-12-30

    The Pipeline Characterization Using Tracers (PCUT) technique uses conservative and partitioning, reactive or other interactive tracers to remotely determine the amount of contaminant within a run of piping or ductwork. The PCUT system was motivated by a method that has been successfully used to characterize subsurface soil contaminants and is similar in operation to that of a gas chromatography column. By injecting a ?slug? of both conservative and partitioning tracers at one end (or section) of the piping and measuring the time history of the concentration of the tracers at the other end (or another section) of the pipe, the presence, location, and amount of contaminant within the pipe or duct can be determined. The tracers are transported along the pipe or duct by a gas flow field, typically air or nitrogen, which has a velocity that is slow enough so that the partitioning tracer has time to interact with the contaminant before the tracer slug completely passes over the contaminate region. PCUT not only identifies the presence of contamination, it also can locate the contamination along the pipeline and quantify the amount of residual. PCUT can be used in support of deactivation and decommissioning (D&D) of piping and ducts that may have been contaminated with hazardous chemicals such as chlorinated solvents, petroleum products, radioactive materials, or heavy metals, such as mercury.

  5. Tracer design for magnetic particle imaging (invited).

    Science.gov (United States)

    Ferguson, R Matthew; Khandhar, Amit P; Krishnan, Kannan M

    2012-04-01

    Magnetic particle imaging (MPI) uses safe iron oxide nanoparticle tracers to offer fundamentally new capabilities for medical imaging, in applications as vascular imaging and ultra-sensitive cancer therapeutics. MPI is perhaps the first medical imaging platform to intrinsically exploit nanoscale material properties. MPI tracers contain magnetic nanoparticles whose tunable, size-dependent magnetic properties can be optimized by selecting a particular particle size and narrow size-distribution. In this paper we present experimental MPI measurements acquired using a homemade MPI magnetometer: a zero-dimensional MPI imaging system designed to characterize tracer performance by measuring the derivative of the time-varying tracer magnetization, M'(H(t)), at a driving frequency of 25 kHz. We show that MPI performance is optimized by selecting phase-pure magnetite tracers of a particular size and narrow size distribution; in this work, tracers with 20 nm median diameter, log-normal distribution shape parameter, σ(v), equal to 0.26, and hydrodynamic diameter equal to 30 nm showed the best performance. Furthermore, these optimized MPI tracers show 4 × greater signal intensity (measured at the third harmonic) and 20% better spatial resolution compared with commercial nanoparticles developed for MRI.

  6. Landscape and bio- geochemical strategy for monitoring transformation and reclamation of the soil mining sites

    Science.gov (United States)

    Korobova, Elena

    2010-05-01

    Sites of active or abandoned mining represent areas of considerable technogenic impact and need scientifically ground organization of their monitoring and reclamation. The strategy of monitoring and reclamation depends on the scale and character of the physical, chemical and biological consequences of the disturbances. The geochemical studies for monitoring and rehabilitation of the career-dump complexes should methodically account of formation of the particular new landforms and the changes in circulation of the remobilized elements of the soil cover. However, the general strategy should account of both the initial and transformed landscape geochemical structure of the area with due regard to the natural and new content of chemical elements in the environmental components. For example the tailings and waste rocks present new geochemical fields with specifically different concentration of chemical elements that cause formation of new geochemical barriers and landscapes. The way of colonization of the newly formed landscapes depends upon the new geochemical features of the technogenic environment and the adaptive ability of local and intrusive flora. The newly formed biogeochemical anomalies need organization of permanent monitoring not only within the anomaly itself but also of its impact zones. Spatial landscape geochemical monitoring combined with bio-geochemical criteria of threshold concentrations seems to be a helpful tool for decision making on reclamation and operation of the soil mining sites to provide a long-term ecologically sustainable development of the impact zone as a whole.

  7. Resolving the Multi-scale Behavior of Geochemical Weathering in the Critical Zone Using High Resolution Hydro-geochemical Models

    Science.gov (United States)

    Pandey, S.; Rajaram, H.

    2015-12-01

    This work investigates hydrologic and geochemical interactions in the Critical Zone (CZ) using high-resolution reactive transport modeling. Reactive transport models can be used to predict the response of geochemical weathering and solute fluxes in the CZ to changes in a dynamic environment, such as those pertaining to human activities and climate change in recent years. The scales of hydrology and geochemistry in the CZ range from days to eons in time and centimeters to kilometers in space. Here, we present results of a multi-dimensional, multi-scale hydro-geochemical model to investigate the role of subsurface heterogeneity on the formation of mineral weathering fronts in the CZ, which requires consideration of many of these spatio-temporal scales. The model is implemented using the reactive transport code PFLOTRAN, an open source subsurface flow and reactive transport code that utilizes parallelization over multiple processing nodes and provides a strong framework for simulating weathering in the CZ. The model is set up to simulate weathering dynamics in the mountainous catchments representative of the Colorado Front Range. Model parameters were constrained based on hydrologic, geochemical, and geophysical observations from the Boulder Creek Critical Zone Observatory (BcCZO). Simulations were performed in fractured rock systems and compared with systems of heterogeneous and homogeneous permeability fields. Tracer simulations revealed that the mean residence time of solutes was drastically accelerated as fracture density increased. In simulations that include mineral reactions, distinct signatures of transport limitations on weathering arose when discrete flow paths were included. This transport limitation was related to both advective and diffusive processes in the highly heterogeneous systems (i.e. fractured media and correlated random permeability fields with σlnk > 3). The well-known time-dependence of mineral weathering rates was found to be the most

  8. Geochemical Enirchment and Mineralization of Indium

    Institute of Scientific and Technical Information of China (English)

    张乾; 战新志; 等

    1998-01-01

    Indium occurs in a very dispersed manner in nature with enrichment of economic in terest rarely known.The highly dispersed nature of indium,among several other elements,has for a long time retarded our understanding of the regularities that control their mineralization,which in turn has hindered exploitation and application of these elements.Recent studies of ours show that no significant enrichment of indium can be recognized in various types of Pb-Zn sulphide deposits as well as in deposits of copper,iron and manganese,Indium Concentrations in ores of these deposits are generally below 10×10-6.In contrast,however,indium is found to be enriched to a significant extent in cassiterite-sulphide deposits and some tin-rich Pb-Zn polymetallic deposits.The average content of indium in these deposits can be over 100×10-6,and more than 90% of it is concentrated in sphalerite.Generally,these deposits may be considered as large paragenic deposits for indium and ,therefore,there must be some regularities that govern the geochemical enrichment of the so-called "dispersed element" indium.

  9. Gas sealing efficiency of cap rocks. Pt. 1: Experimental investigations in pelitic sediment rocks. - Pt. 2: Geochemical investigations on redistribution of volatile hydrocarbons in the overburden of natural gas reservoirs; Gas sealing efficiency of cap rocks. T. 1: Experimentelle Untersuchungen in pelitischen Sedimentgesteinen. - T.2: Geochemische Untersuchungen zur Umverteilung leichtfluechtiger Kohlenwasserstoffe in den Deckschichten von Erdgaslagerstaetten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Leythaeuser; Konstanty, J.; Pankalla, F.; Schwark, L.; Krooss, B.M.; Ehrlich, R.; Schloemer, S.

    1997-09-01

    New methods and concepts for the assessment of sealing properties of cap rocks above natural gas reservoirs and of the migration behaviour of low molecular-weight hydrocarbons in sedimentary basins were developed and tested. The experimental work comprised the systematic assesment of gas transport parameters on representative samples of pelitic rocks at elevated pressure and temperature conditions, and the characterization of their sealing efficiency as cap rocks overlying hydrocarbon accumulations. Geochemical case histories were carried out to analyse the distribution of low molecular-weight hydrocarbons in the overburden of known natural gas reservoirs in NW Germany. The results were interpreted with respect to the sealing efficiency of individual cap rock lithologies and the type and extent of gas losses. (orig.) [Deutsch] Zur Beurteilung der Abdichtungseigenschaften von Caprocks ueber Gaslagerstaetten und des Migrationsverhaltens niedrigmolekularer Kohlenwasserstoffe in Sedimentbecken wurden neue Methoden und Konzepte entwickelt und angewendet. In experimentellen Arbeiten erfolgte die systematische Bestimmung von Gas-Transportparametern an repraesentativen Proben pelitischer Gesteine unter erhoehten Druck- und Temperaturbedingungen und die Charakterisierung ihrer Abdichtungseffizienz als Deckschicht ueber Kohlenwasserstofflagerstaetten. In geochemischen Fallstudien wurde die Verteilung niedrigmolekularer Kohlenwasserstoffe in den Deckschichten ueber bekannten Erdgaslagerstaetten in NW-Deutschland analysiert und im Hinblick auf die Abdichtungseffizienz einzelner Caprock-Lithologien bzw. Art und Ausmass von Gasverlusten interpretiert. (orig.)

  10. Long-Lived, Sub-Surface Layers of Toxic Oil in the Deep-Sea: A Molecular Organic and Isotopic Geochemical Approach to Understanding their Nature, Molecular Distribution, Origin and Impact to the Northern Gulf of Mexico

    Science.gov (United States)

    Hollander, D. J.; Freeman, K. H.; Ellis, G.; Diefendorf, A. F.; Peebles, E. B.; Paul, J.

    2010-12-01

    Here we present the results from two research cruises to the Northern Gulf of Mexico (GoM) during May and August 2010, after the April 20th blowout of BP’s Deepwater Horizon (DWH) drilling rig. Not only was the DWH tragedy the largest oil spill to have ever occurred in the United States but it was also the first blowout of a deep-sea oil exploration well. The BP oil spill presents the scientific community with a critically important and unique opportunity: i) to characterize the occurrence, molecular distribution and abundance of the hydrocarbons in the sub-surface, ii) to identify the source of the oil in the environment and, iii) to study how the distribution and chemistry of the hydrocarbons change over time and space and whether the sub-surface hydrocarbons are toxic to marine plankton and bacteria. Using sonar, fluorometry and backscatter, we were able to trace the occurrence of layers of sub-surface oil. These oil layers were found suspended at depths of 400 m and 1000-1400 m in the form of small microdroplets that were not visible to the naked eye. Both the 400 and the 1000 m layers were traced for more than 20 miles in length and 4 miles in width. Molecular organic geochemical analyses determined that petroleum hydrocarbons were the dominant components of the 400 and 1000 m layers. Interesting, the distribution of compounds was extremely consistent among all the samples with n-alkanes ranging from C24 to C37 with a maximum at C28. The loss of the lower molecular weight components of the crude oil is attributed to biodegradation. This distribution of n-alkanes was the same regardless of whether the samples were from 400 or 1000 m, whether the sites were 25 or 45 miles from the DWH site or whether the samples were collected in May or August. These observations strongly suggest that the bacteria are not able to consume all of the oil, and that these higher molecular weight compounds may persist in the environment for extended lengths of time, at least months

  11. Compartmental modeling and tracer kinetics

    CERN Document Server

    Anderson, David H

    1983-01-01

    This monograph is concerned with mathematical aspects of compartmental an­ alysis. In particular, linear models are closely analyzed since they are fully justifiable as an investigative tool in tracer experiments. The objective of the monograph is to bring the reader up to date on some of the current mathematical prob­ lems of interest in compartmental analysis. This is accomplished by reviewing mathematical developments in the literature, especially over the last 10-15 years, and by presenting some new thoughts and directions for future mathematical research. These notes started as a series of lectures that I gave while visiting with the Division of Applied ~1athematics, Brown University, 1979, and have developed in­ to this collection of articles aimed at the reader with a beginning graduate level background in mathematics. The text can be used as a self-paced reading course. With this in mind, exercises have been appropriately placed throughout the notes. As an aid in reading the material, the e~d of a ...

  12. Determination of the sediment oxidation capacity by column and field experiments with reactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Dethlefsen, F.; Bliss, F.; Wachter, T.; Dahmke, A. [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Meckenstock, R. [Tuebingen Univ. (Germany). Zentrum fuer Angewandte Geowissenschaften

    2003-07-01

    The oxidation capacity of ferric iron in column studies was determined by phosphate tracer tests and validated by biodegradation experiments with toluene as a carbon source and the iron(III)-oxide reducing bacterium Geobacter metallireducens as well as with wet chemical extraction. Toluene mass balance, Fe(II) production and tracer test results showed that about 1/3 of the total Fe(III) mass had been reduced during the biodegradation experiment. The redox reactive tracer sulfide is supposed to be more practicable for field purposes, because a sulfide mass or electron balance enables evaluation of the tracer test. In this way, consideration of mineral specific sorption parameters and long residence periods of a sorptive reactive tracer can be avoided. Laboratory column experiments were performed with an artificially composed sediment (quartz sand and ferrihydrite) as well as with natural sediments from the margin of the benzene contaminated RETZINA test site in Zeitz (Germany). Fast reaction kinetics of sulfide with iron(III) minerals allowed the observation of a successive fixation of black iron sulfides in all the glas columns. Depending on the mineral iron content, the sedimentary oxidation capacity of the column material was used up in few days to weeks. Mass of sulfide reacted in the tracer test and sulfide mass recovered by sediment extraction after the experiment were in very good agreement. Evaluation of the column experiments confirmed the calculated ratio that 3 molar equivalents sulfide were used to reduce and fix 2 molar equivalents of Fe(III). Mean Fe(III) content of natural sediment samples (drilling SafZz 28/02 in Zeitz) was 0.35 mg/g sediment determined by laboratory sulfide tracer test and 5 M HCl extractions. Finally, a single well push-pull test was performed at the RETZINA test site Zeitz to test the applicability of the sulfide tracer in a field-scale experiment. (orig.)

  13. Proceedings of the workshop on geochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices.

  14. Use of isotopologues as natural tracers of ground water application to Engenho Nogueira watershed, UFMG campus, Brazil; Uso de isotopologos como tracadores naturais das aguas subterraneas: aplicacao a bacia do corrego Engenho Nogueira, campus UFMG

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Raquel Pazzini Scarpelli de

    2015-07-01

    Isotope Ratio Mass Spectrometry is the ideal method to determine with high precision the ratio of stable isotopes of light elements. Due to this fact, it is used in environmental research, especially in hydrological studies, avoiding the need of injection. This work implanted a method for analysis of water isotopes ({sup 18}O and {sup 2}H) and validated the method for the measurement of δ{sup 18}O, in the Laboratory of Isotope Ratio Mass Spectrometry of the Center for Development of Nuclear Technology. The performance of the method was evaluated according to the following criteria: stability, linearity, precision, accuracy and robustness. This method was applied to studies of groundwater in the watershed of the Engenho Nogueira Creek, located at the Federal University of Minas Gerais (UFMG) campus, in the northern region of the city of Belo Horizonte, Brazil. The watershed of the Engenho Nogueira Creek has been studied in several occasions in recent years for different purposes; however, the use of natural isotopes of water had never been applied to these studies. This technique can expand the diversity of data on the local aquifer, helping to fill gaps in its understanding, besides, it can confirm data previously obtained. The expansion of the academic and administrative units of the UFMG campus since 2000 implies in an incremented importance of the management of the local since the demand for water grows each year. (author)

  15. A galaxy-halo model for multiple cosmological tracers

    Science.gov (United States)

    Bull, Philip

    2017-10-01

    The information extracted from large galaxy surveys with the likes of DES, DESI, Euclid, LSST, SKA, and WFIRST will be greatly enhanced if the resultant galaxy catalogues can be cross-correlated with one another. Predicting the nature of the information gain, and developing the tools to realize it, depends on establishing a consistent model of how the galaxies detected by each survey trace the same underlying matter distribution. Existing analytic methods, such as halo occupation distribution modelling, are not well suited for this task, and can suffer from ambiguities and tuning issues when applied to multiple tracers. In this paper, we take the first step towards constructing an alternative that provides a common model for the connection between galaxies and dark matter haloes across a wide range of wavelengths (and thus tracer populations). This is based on a chain of parametrized statistical distributions that model the connection between (i) halo mass and bulk physical properties of galaxies, such as star formation rate; and (ii) those same physical properties and a variety of emission processes. The result is a flexible parametric model that allows analytic halo model calculations of one-point functions to be carried out for multiple tracers, as well as providing semi realistic galaxy properties for fast mock catalogue generation.

  16. Studies of Tracer Dispersion and Fluid Flow in Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Rage, T.

    1996-12-31

    This doctoral thesis explores the connection between the topology of a porous medium and its macroscopic transport properties and is based on computerized simulation. In porous media, both diffusion and convection contribute to the dispersion of a tracer and their combined effect is emphasized. The governing equations are solved numerically, using finite differences and Monte Carlo technique. The influence of finite Reynolds number on the outcome of echo-experiments is discussed. Comparing experiments and simulations it is found that nonlinear inertial forces lead to a visible deformation of a returned tracer at surprisingly small Reynolds numbers. In a study of tracer dispersion and fluid flow in periodic arrays of discs it is demonstrated that the mechanisms of mechanical dispersion in periodic media and in natural (non-periodic) porous media are essentially different. Measurements of the percolation probability distribution of a sandstone sample is presented. Local porosity theory predicts that this simple geometric function of a porous medium is of dominant importance for its macroscopic transport properties. It is demonstrated that many aspects of transport through fractures can be studied by using simple but realistic models and readily available computer resources. An example may be the transport of hydrocarbon fluids from the source rock to a reservoir. 165 refs., 44 figs., 1 table

  17. Thermal tracer tomography: from numerical simulation to field implementation

    Science.gov (United States)

    Somogyvári, Márk; Brauchler, Ralf; Bayer, Peter

    2016-04-01

    Choosing heat for subsurface investigations is attractive because changes in temperature can be easily measured, and natural variations are typically slower than the timescale of the experiments. The tomographical setup expands the applicability of such tests to reconstruct the spatial distribution of hydraulic aquifer properties. A new inversion methodology is presented for thermal tracer tomography, using tracer travel times to invert the hydraulic conductivity distribution of the aquifer. If we can assume that heat transport is driven by advection, the travel time of the thermal tracer can be related to the hydraulic parameters of the aquifer. With this assumption other thermal effects such as thermal diffusion or density driven flow appear as noise in the results. To reduce these effects the early time diagnostics of the recorded breakthrough curves are used, focusing on the fastest transport routes between the sources and receivers. The inverse problem of the experiment thus can be formulated as a classical travel time problem, and it can be solved using standard eikonal solver algorithms known from seismic or hydraulic tomography. The method is demonstrated with a high resolution 3-D aquifer analog dataset. The generated 3-D reconstruction reveals the potential of the method, especially in finding the preferential flow paths within the aquifer. Aside from this, the developed method is computationally efficient and can provide results in a fragment of the time required for full-physics model calibration. The method is also tested under field conditions. Four heat tracer injections were performed during a three day field campaign at the Widen field site in northeast Switzerland. Pulse signals were used and the temperature evolution was measured downstream using a distributed measurement system. The preliminary results of the tomographic inversion correspond well with the findings of earlier studies from the field site imaging the same geological features as

  18. Tracer monitoring of enhanced oil recovery projects

    Directory of Open Access Journals (Sweden)

    Kleven R.

    2013-05-01

    Full Text Available In enhanced oil recovery (EOR, chemicals are injected into the oil reservoir, either to increase macroscopic sweep efficiency, or to reduce remaining oil saturation in swept zones. Tracers can be used to identify reservoirs that are specifically suited for EOR operations. Injection of a selection of partitioning tracers, combined with frequent sample analysis of produced fluids, provides information suited for estimation of residual oil saturation. Tracers can also be used to evaluate and optimize the application of EOR chemicals in the reservoir. Suitable tracers will follow the EOR chemicals and assist in evaluation of retention, degradation or trapping. In addition to field applications, tracers also have a large potential as a tool to perform mechanistic studies of EOR chemicals in laboratory experiments. By labelling EOR chemicals with radioactive isotopes of elements such as H, C and S, detailed studies of transport mechanisms can be carried out. Co-injection of labelled compounds in dynamic flooding experiments in porous media will give information about retention or separation of the unique compounds constituting the chemical formulation. Separation of such compounds may be detrimental to obtaining the EOR effect expected. The paper gives new information of specific methods, and discusses current status for use of tracers in EOR operations.

  19. Geochemical evolution processes and water-quality observations based on results of the National Water-Quality Assessment Program in the San Antonio segment of the Edwards aquifer, 1996-2006

    Science.gov (United States)

    Musgrove, MaryLynn; Fahlquist, Lynne; Houston, Natalie A.; Lindgren, Richard J.; Ging, Patricia B.

    2010-01-01

    As part of the National Water-Quality Assessment Program, the U.S. Geological Survey collected and analyzed groundwater samples during 1996-2006 from the San Antonio segment of the Edwards aquifer of central Texas, a productive karst aquifer developed in Cretaceous-age carbonate rocks. These National Water-Quality Assessment Program studies provide an extensive dataset of groundwater geochemistry and water quality, consisting of 249 groundwater samples collected from 136 sites (wells and springs), including (1) wells completed in the shallow, unconfined, and urbanized part of the aquifer in the vicinity of San Antonio (shallow/urban unconfined category), (2) wells completed in the unconfined (outcrop area) part of the regional aquifer (unconfined category), and (3) wells completed in and springs discharging from the confined part of the regional aquifer (confined category). This report evaluates these data to assess geochemical evolution processes, including local- and regional-scale processes controlling groundwater geochemistry, and to make water-quality observations pertaining to sources and distribution of natural constituents and anthropogenic contaminants, the relation between geochemistry and hydrologic conditions, and groundwater age tracers and travel time. Implications for monitoring water-quality trends in karst are also discussed. Geochemical and isotopic data are useful tracers of recharge, groundwater flow, fluid mixing, and water-rock interaction processes that affect water quality. Sources of dissolved constituents to Edwards aquifer groundwater include dissolution of and geochemical interaction with overlying soils and calcite and dolomite minerals that compose the aquifer. Geochemical tracers such as magnesium to calcium and strontium to calcium ratios and strontium isotope compositions are used to evaluate and constrain progressive fluid-evolution processes. Molar ratios of magnesium to calcium and strontium to calcium in groundwater typically

  20. Analysis of tracer and thermal transients during reinjection

    Energy Technology Data Exchange (ETDEWEB)

    Kocabas, I.

    1989-10-01

    This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.

  1. Evaluation of leakage from fume hoods using tracer gas, tracer nanoparticles and nanopowder handling test methodologies.

    Science.gov (United States)

    Dunn, Kevin H; Tsai, Candace Su-Jung; Woskie, Susan R; Bennett, James S; Garcia, Alberto; Ellenbecker, Michael J

    2014-01-01

    The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tracer gas (sulfur hexafluoride) and nanoparticles as well as an active test using an operator handling nanoalumina were conducted. A commercially available particle generator was used to produce sodium chloride tracer nanoparticles. Containment effectiveness was evaluated by sampling both in the breathing zone (BZ) of a mannequin and operator as well as across the hood opening. These containment tests were conducted across a range of hood face velocities (60, 80, and 100 ft/min) and with the room ventilation system turned off and on. For the tracer gas and tracer nanoparticle tests, leakage was much more prominent on the left side of the hood (closest to the room supply air diffuser) although some leakage was noted on the right side and in the BZ sample locations. During the tracer gas and tracer nanoparticle tests, leakage was primarily noted when the room air conditioner was on for both the low and medium hood exhaust airflows. When the room air conditioner was turned off, the static tracer gas tests showed good containment across most test conditions. The tracer gas and nanoparticle test results were well correlated showing hood leakage under the same conditions and at the same sample locations. The impact of a room air conditioner was demonstrated with containment being adversely impacted during the use of room air ventilation. The tracer nanoparticle approach is a simple method requiring minimal setup and instrumentation. However, the method requires the reduction in

  2. Journal: A Review of Some Tracer-Test Design Equations for Tracer-Mass Estimation and Sample Collection Frequency

    Science.gov (United States)

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estima...

  3. Journal: A Review of Some Tracer-Test Design Equations for Tracer-Mass Estimation and Sample Collection Frequency

    Science.gov (United States)

    Determination of necessary tracer mass, initial sample-collection time, and subsequent sample-collection frequency are the three most difficult aspects to estimate for a proposed tracer test prior to conducting the tracer test. To facilitate tracer-mass estimation, 33 mass-estima...

  4. Geochemical modelling baseline compositions of groundwater

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard;

    2008-01-01

    and variations in water chemistry that are caused by large scale geochemical processes taking place at the timescale of thousands of years. The most important geochemical processes are ion exchange (Valreas and Aveiro) where freshwater solutes are displacing marine ions from the sediment surface, and carbonate...... dissolution (East Midlands, Valreas and Aveiro). Reactive transport models, employing the code PHREEQC, which included these geochemical processes and one-dimensional solute transport were able to duplicate the observed patterns in water quality. These models may provide a quantitative understanding...

  5. Identifying paleotsunami deposits in Thailand using geochemical analyses

    Science.gov (United States)

    Löwhagen, Linda; Jankaew, Kruawun; Kylander, Malin; Wohlfarth, Barbara

    2014-05-01

    Paleotsunami research has received considerable attention following the devastating Indian Ocean tsunami of December 2004. Specific questions involve the magnitude, frequency and impact of past tsunamis. Phra Thong Island in the eastern Andaman Sea is an ideal location to study paleotsunami deposits in great detail (Jankaew et al., 2008). Apart from the 2004 Indian Ocean tsunami layer, three more distinct tsunami layers, separated by soil horizons have been identified and dated (Jankaew et al., 2008). In a collaborative project between Stockholm University and Chulalongkorn University, four sites on Phra Thong Island were chosen for detailed geochemical studies and additional AMS 14C dating. Paleotsunami deposits at these sites can be seen as more or less distinct sand layers embedded between the peaty soils. Here we report the initial results of XRF core scanning and loss on ignition analysis, which are supplemented by new 14C dates. The XRF data sets show a good correlation between synchronous tsunami layers along a coast-inland transect. The geochemistry moreover suggests a change in source area for the oldest tsunami layer. Further work will focus on a detailed geochemical characterization of the tsunami and soil layers, and on the influence of soil processes on the geochemical record. Reference: Jankaew, K; Atwater, B; Sawai, Y; Choowong, M; Charoentitirat, T; Martin, M; Prendergast, A, 2008. Medieval forewarning of the 2004 Indian Ocean tsunami in Thailand. Nature 455, 1228-1231.

  6. Estimates of tracer-based piston-flow ages of groundwater from selected sites-National Water-Quality Assessment Program, 1992-2005

    Science.gov (United States)

    Hinkle, Stephen R.; Shapiro, Stephanie D.; Plummer, L. Niel; Busenberg, Eurybiades; Widman, Peggy K.; Casile, Gerolamo C.; Wayland, Julian E.

    2011-01-01

    -flow model is based on the potentially limiting assumptions that tracer transport is advective and that no mixing occurs. Additional uncertainties can arise from tracer degradation, sorption, contamination, or fractionation; terrigenic (natural) sources of tracers; spatially variable atmospheric tracer concentrations; and incomplete understanding of mechanisms of recharge or of the conditions under which atmospheric tracers were partitioned to recharge. The effects of some of these uncertainties are considered herein. For example, degradation, contamination, or fractionation often can be identified or inferred. However, detailed analysis of the effects of such uncertainties on the tracer-based piston-flow ages is constrained by sparse data and an absence of complementary lines of evidence, such as detailed solute transport simulations. Thus, the tracer-based piston-flow ages compiled in this report represent only an initial interpretation of the tracer data.

  7. Appalachian basin oil and natural gas: stratigraphic framework, total petroleum systems, and estimated ultimate recovery: Chapter C.1 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    Science.gov (United States)

    Ryder, Robert T.; Milici, Robert C.; Swezey, Christopher S.; Trippi, Michael H.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    The most recent U.S. Geological Survey (USGS) assessment of undiscovered oil and gas resources of the Appalachian basin was completed in 2002 (Milici and others, 2003). This assessment was based on the total petroleum system (TPS), a concept introduced by Magoon and Dow (1994) and developed during subsequent studies such as those by the U.S. Geological Survey World Energy Assessment Team (2000) and by Biteau and others (2003a,b). Each TPS is based on specific geologic elements that include source rocks, traps and seals, reservoir rocks, and the generation and migration of hydrocarbons. This chapter identifies the TPSs defined in the 2002 Appalachian basin oil and gas assessment and places them in the context of the stratigraphic framework associated with regional geologic cross sections D–D′ (Ryder and others, 2009, which was re-released in this volume, chap. E.4.1) and E–E′ (Ryder and others, 2008, which was re-released in this volume, chap. E.4.2). Furthermore, the chapter presents a recent estimate of the ultimate recoverable oil and natural gas in the basin.

  8. Testing and comparison of four ionic tracers to measure stream flow loss by multiple tracer injection

    Science.gov (United States)

    Zellweger, G.W.

    1994-01-01

    An injectate containing lithium, sodium, chloride and bromide was added continuously at five sites along a 507 m study reach of St Kevin Gulch, Lake County, Colorado to determine which sections of the stream were losing water to the stream bed and to ascertain how well the four tracers performed. The acidity of the stream (pH 3.6) made it possible for lithium and sodium, which are normally absorbed by ion exchange with stream bed sediment, to be used as conservative tracers. Net flow losses as low as 0.81 s-1, or 8% of flow, were calculated between measuring sites. By comparing the results of simultaneous injection it was determined whether subsections of the study reach were influent or effluent. Evaluation of tracer concentrations along 116 m of stream indicated that all four tracers behaved conservatively. Discharges measured by Parshall flumes were 4-18% greater than discharges measured by tracer dilution. -from Author

  9. Estimation of Fluorescent Dye Amount in Tracer Dye Test

    Science.gov (United States)

    Pekkan, Emrah; Balkan, Erman; Balkan, Emir

    2015-04-01

    Karstic groundwater is more influenced by human than the groundwater that disperse in pores. On the other hand karstic groundwater resources, in addition to providing agricultural needs, livestock breeding, drinking and domestic water in most of the months of the year, they also supply drinking water to the wild life at high altitudes. Therefore sustainability and hydrogeological investigation of karstic resources is critical. Tracing techniques are widely used in hydrologic and hydrogeologic studies to determine water storage, flow rate, direction and protection area of groundwater resources. Karanfil Mountain (2800 m), located in Adana, Turkey, is one of the karstic recharge areas of the natural springs spread around its periphery. During explorations of the caves of Karanfil mountain, a 600 m deep cave was found by the Turkish and Polish cavers. At the bottom of the cave there is an underground river with a flow rate of approximately 0.5 m3/s during August 2014. The main spring is located 8 km far from the cave's entrance and its mean flow rate changes between 3.4 m3/s and 0.21 m3/s in March and September respectively according to a flowrate observation station of Directorate of Water Works of Turkey. As such frequent storms, snowmelt and normal seasonal variations in rainfall have a significant and rapid effect on the volume of this main spring resource. The objective of our research is to determine and estimate dye amount before its application on the field inspired from the previously literature on the subject. This estimation is intended to provide a preliminary application of a tracer test of a karstic system. In this study dye injection, inlet point will be an underground river located inside the cave and the observation station will be the spring that is approximately 8 km far from the cave entrance. On the other hand there is 600 meter elevation difference between cave entrance and outlet spring. In this test Rodamin-WT will be used as tracer and the

  10. TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

    Science.gov (United States)

    Turner, P. R.

    1994-01-01

    TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

  11. TRACER - TRACING AND CONTROL OF ENGINEERING REQUIREMENTS

    Science.gov (United States)

    Turner, P. R.

    1994-01-01

    TRACER (Tracing and Control of Engineering Requirements) is a database/word processing system created to document and maintain the order of both requirements and descriptive material associated with an engineering project. A set of hierarchical documents are normally generated for a project whereby the requirements of the higher level documents levy requirements on the same level or lower level documents. Traditionally, the requirements are handled almost entirely by manual paper methods. The problem with a typical paper system, however, is that requirements written and changed continuously in different areas lead to misunderstandings and noncompliance. The purpose of TRACER is to automate the capture, tracing, reviewing, and managing of requirements for an engineering project. The engineering project still requires communications, negotiations, interactions, and iterations among people and organizations, but TRACER promotes succinct and precise identification and treatment of real requirements separate from the descriptive prose in a document. TRACER permits the documentation of an engineering project's requirements and progress in a logical, controllable, traceable manner. TRACER's attributes include the presentation of current requirements and status from any linked computer terminal and the ability to differentiate headers and descriptive material from the requirements. Related requirements can be linked and traced. The program also enables portions of documents to be printed, individual approval and release of requirements, and the tracing of requirements down into the equipment specification. Requirement "links" can be made "pending" and invisible to others until the pending link is made "binding". Individuals affected by linked requirements can be notified of significant changes with acknowledgement of the changes required. An unlimited number of documents can be created for a project and an ASCII import feature permits existing documents to be incorporated

  12. Role of geochemical background at evaluation of investment attractiveness of recreational territories

    Directory of Open Access Journals (Sweden)

    Vdovina Ol'ga Konstantinovna

    2014-09-01

    Full Text Available The article shows the role of natural geochemical background when estimating investment attractiveness of recreational areas. It is noted, that geochemical background influence on people's sickness rate isn't considered now. Though it's understood, that even insignificant increase of geochemical background in relation to percentage abundance of Earth crest may lead to endemic diseases of people, animals and plants. An indicator of geochemical endemicity areas was proposed for assessing the impact of storage elements and of a lack of geological environment on human health. Thanks to this measure, and taking into account landscape features of the area, the authors allocated lands, dangerous and potentially dangerous in terms of endemicity. The importance of ratings was achieved by the use of those factors that could have a great influence on the cost of land development. This includes, first of all, the factors that affect population health, and economic and geographic factors that minimize the cost of the territory development and the factors that give rise to financial risks and risks of human losses. The main risk factors include: potential ecological and geochemical risk; high absolute heights, development and activity of dangerous geological processes and phenomena. Systemacity of researches was reached by using factors, that characterize the object from different aspects; readiness of area infrastructure to its exploration and possible risks. Objectivity was achieved by the use of figures obtained from the results of geochemical and engineering surveys with their metrological support.

  13. Time Passes - Argon Isotopes as Tracers of Fluids in the Earth's Crust

    Science.gov (United States)

    Kelley, Simon P.

    2016-04-01

    Recent experimental measurements of noble gas solubility in silicate minerals (e.g. Jackson et al. 2013, 2015) means that we can begin to explore the use of noble gas partition between minerals and fluids to understand their residence and transport in the Earth's crust. One starting point for this exploration is the distribution of noble gases and halogens in crustal fluids which was reviewed by Kendrick and Burnard (2013). In particular, K&B (2013) noted that time is a key parameter in understanding noble gas tracers in crustal processes; yielding information such as the residence time of water in a reservoir based on 4He acquired from aquifer rocks, and the 40Ar/39Ar age of fluid inclusions based on trapped fluid and minerals in quartz. Argon isotope variations in natural systems have been measured during studies of 40Ar/39Ar ages to quantify the rates and timescales of crustal processes. There are also studies of fluids in similar rocks, notably in fluid inclusions, providing the opportunity to quantify the variations in the crust. Partition of argon between mineral phases under conditions of varying fluid availability can be compared in systems where 40Ar/39Ar measurements indicate the preservation of non-radiogenic argon (both excess and atmospheric) in the minerals. Rather than a simple picture of radiogenic argon contents increasing with crustal age, and gradual depletion of atmospheric argon in deeper fluids, what emerges is a sometimes dynamic and sometimes static system in different zones of the crust. While it can be shown that the hydrous fluid in sandstone reservoirs contained excess argon, analyses of authigenic minerals rarely exhibit 40Ar/39Ar ages in excess of the growth age. In this scenario, the incompatible nature of argon means that the fluid acts as an effective infinite reservoir and radiogenic argon dominates the potassium rich authigenic minerals. The controls on noble gas distribution are also well illustrated by deep crustal rocks such as

  14. Evaluation of multiple tracer methods to estimate low groundwater flow velocities.

    Science.gov (United States)

    Reimus, Paul W; Arnold, Bill W

    2017-04-01

    Four different tracer methods were used to estimate groundwater flow velocity at a multiple-well site in the saturated alluvium south of Yucca Mountain, Nevada: (1) two single-well tracer tests with different rest or "shut-in" periods, (2) a cross-hole tracer test with an extended flow interruption, (3) a comparison of two tracer decay curves in an injection borehole with and without pumping of a downgradient well, and (4) a natural-gradient tracer test. Such tracer methods are potentially very useful for estimating groundwater velocities when hydraulic gradients are flat (and hence uncertain) and also when water level and hydraulic conductivity data are sparse, both of which were the case at this test location. The purpose of the study was to evaluate the first three methods for their ability to provide reasonable estimates of relatively low groundwater flow velocities in such low-hydraulic-gradient environments. The natural-gradient method is generally considered to be the most robust and direct method, so it was used to provide a "ground truth" velocity estimate. However, this method usually requires several wells, so it is often not practical in systems with large depths to groundwater and correspondingly high well installation costs. The fact that a successful natural gradient test was conducted at the test location offered a unique opportunity to compare the flow velocity estimates obtained by the more easily deployed and lower risk methods with the ground-truth natural-gradient method. The groundwater flow velocity estimates from the four methods agreed very well with each other, suggesting that the first three methods all provided reasonably good estimates of groundwater flow velocity at the site. The advantages and disadvantages of the different methods, as well as some of the uncertainties associated with them are discussed. Published by Elsevier B.V.

  15. Heavy Metal Pollution Assessment by Partial Geochemical ...

    African Journals Online (AJOL)

    Bheema

    sediments geochemical anomalies has been applied with success in .... pure exploration geological to environmental pollution studies as well as remote sensing ..... erosion of the amorphous phase to the sea in the form of suspension while ...

  16. Statistical Analysis Of Reconnaissance Geochemical Data From ...

    African Journals Online (AJOL)

    Statistical Analysis Of Reconnaissance Geochemical Data From Orle District, ... The univariate methods used include frequency distribution and cumulative ... The possible mineral potential of the area include base metals (Pb, Zn, Cu, Mo, etc.) ...

  17. The National Geochemical Survey - database and documentation

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS, in collaboration with other federal and state government agencies, industry, and academia, is conducting the National Geochemical Survey (NGS) to produce...

  18. The National Geochemical Survey - database and documentation

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS, in collaboration with other federal and state government agencies, industry, and academia, is conducting the National Geochemical Survey (NGS) to produce a...

  19. Asbestos. LC Science Tracer Bullet.

    Science.gov (United States)

    Evans, Joanna, Comp.

    Asbestos is a generic term that refers to several silicate materials occurring naturally as fibrous rocks. Insignificant amounts of asbestos fiber can be found in ambient air, but this, and materials containing hard asbestos, usually do not create problems. Soft materials, however, can release high amounts of asbestos fibers into the air, and…

  20. Principles of landscape-geochemical studies in the zones contaminated by technogenical radionuclides for ecological and geochemical mapping

    Science.gov (United States)

    Korobova, Elena; Romanov, Sergey

    2013-04-01

    Efficiency of landscape-geochemical approach was proved to be helpful in spatial and temporal evaluation of the Chernobyl radionuclide distribution in the environment. The peculiarity of such approach is in hierarchical consideration of factors responsible for radionuclide redistribution and behavior in a system of inter-incorporated landscape-geochemical structures of the local and regional scales with due regard to the density of the initial fallout and patterns of radionuclide migration in soil-water-plant systems. The approach has been applied in the studies of distribution of Cs-137, Sr-90 and some other radionuclides in soils and vegetation cover and in evaluation of contribution of the stable iodine supply in soils to spatial variation of risk of thyroid cancer in areas subjected to radioiodine contamination after the Chernobyl accident. The main feature of the proposed approach is simultaneous consideration of two types of spatial heterogeneities: firstly, the inhomogeneity of external radiation exposure due to a complex structure of the contamination field, and, secondly, the landscape geochemical heterogeneity of the affected area, so that the resultant effect of radionuclide impact could significantly vary in space. The main idea of risk assessment in this respect was to reproduce as accurately as possible the result of interference of two surfaces in the form of risk map. The approach, although it demands to overcome a number of methodological difficulties, allows to solve the problems associated with spatially adequate protection of the affected population and optimization of the use of contaminated areas. In general it can serve the basis for development of the idea of the two-level structure of modern radiobiogeochemical provinces formed by superposition of the natural geochemical structures and the fields of technogenic contamination accompanied by the corresponding peculiar and integral biological reactions.

  1. Geochemical Characteristics and Sources of Natural Gas from the South Margin of Junggar Basin%准噶尔盆地南缘天然气地球化学特征及来源

    Institute of Scientific and Technical Information of China (English)

    吴小奇; 黄士鹏; 廖凤蓉; 李振生

    2011-01-01

    准噶尔盆地南缘天然气分布较为广泛,在3排背斜带均有分布.该区天然气在组分上以烃类为主,其中甲烷占主导;普遍含有氮气和二氧化碳.准噶尔盆地南缘天然气均为典型热成因气,主要为源自中、下侏罗统成熟-过成熟煤系烃源岩的煤成气,其中第一排背斜带和第二排背斜带天然气均为典型高-过成熟阶段煤成气,第三排背斜带独山子背斜下古近统和呼图壁背斜所有气样也是该类型,第三排背斜带其余煤成气样为典型成熟阶段煤成气.准噶尔盆地南缘煤成气普遍具有碳同位素部分倒转的特征,其主要由于同型不同源(侏罗系不同层位)气的混合,也有部分由于细菌氧化作用(古牧地背斜)或油型气和煤成气的混合(齐古和安集海).该区油型气样品较少,目前发现的2个油型气样品位于卡因迪克油田白垩系和独山子油气田古近系,分别为成熟和高-过成熟阶段油型气,来自白垩系和二叠系腐泥型烃源岩.齐古背斜二叠系和三叠系中煤成气主要是由断裂下盘埋深较大的下侏罗统八道湾组煤系烃源岩所生成,而侏罗系中煤成气则主要来自中侏罗统西山窑组和下侏罗统三工河组烃源岩,其埋深相对较浅,成熟度相对较低,因此生成的天然气碳同位素值和甲烷含量均相对较小.%Natural gas distributes widely in all the three anticline belts in the south margin of Junggar basin.It is mainly composed of hydrocarbons, in which methane is dominated, often with nitrogen and carbon dioxide. The gas is typically thermogenic, and mainly coal-derived from Middle-Lower Jurassic mature-over mature coal-measure source rocks. The natural gas in the first and second anticline belts, and part of the third anticline belt (Dushanzi anticline of Lower Paleogene and Hutubi anticline) is typical high-over mature coal-derived, while that in the other part of the third anticline belt is typical mature coal

  2. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  3. Transformationally decoupling clustering and tracer bias

    CERN Document Server

    Neyrinck, Mark C

    2014-01-01

    Gaussianizing transformations are used statistically in many non-cosmological fields, but in cosmology, we are only starting to apply them. Here I explain a strategy of analyzing the 1-point function (PDF) of a spatial field, together with the 'essential' clustering statistics of the Gaussianized field, which are invariant to a local transformation. In cosmology, if the tracer sampling is sufficient, this achieves two important goals. First, it can greatly multiply the Fisher information, which is negligible on nonlinear scales in the usual $\\delta$ statistics. Second, it decouples clustering statistics from a local bias description for tracers such as galaxies.

  4. Geologic flow characterization using tracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Klett, R. D.; Tyner, C. E.; Hertel, Jr., E. S.

    1981-04-01

    A new tracer flow-test system has been developed for in situ characterization of geologic formations. This report describes two sets of test equipment: one portable and one for testing in deep formations. Equations are derived for in situ detector calibration, raw data reduction, and flow logging. Data analysis techniques are presented for computing porosity and permeability in unconfined isotropic media, and porosity, permeability and fracture characteristics in media with confined or unconfined two-dimensional flow. The effects of tracer pulse spreading due to divergence, dispersion, and porous formations are also included.

  5. Direct-push delivery of dye tracers for direct documentation of solute distribution in clay till

    DEFF Research Database (Denmark)

    Christiansen, Camilla Maymann; Damgaard, Ida; Broholm, Mette Martina

    2012-01-01

    at an uncontaminated, naturally fractured, basal clay till site (K∼10-7-10-10-m/s) in 2008-2009. A mixture of tracers (brilliant blue, fluorescein, and Rhodamine WT), the characteristics of which are comparable to several current remediation amendments, was delivered in aqueous solution at pressures of ∼5-10 bar...

  6. A review of methods for modelling environmental tracers in groundwater: Advantages of tracer concentration simulation

    Science.gov (United States)

    Turnadge, Chris; Smerdon, Brian D.

    2014-11-01

    Mathematical models of varying complexity have been developed since the 1960s to interpret environmental tracer concentrations in groundwater flow systems. This review examines published studies of model-based environmental tracer interpretation, the progress of different modelling approaches, and also considers the value of modelling tracer concentrations directly rather than estimations of groundwater age. Based on citation metrics generated using the Web of Science and Google Scholar reference databases, the most highly utilised interpretation approaches are lumped parameter models (421 citations), followed closely by direct age models (220 citations). A third approach is the use of mixing cell models (99 citations). Although lumped parameter models are conceptually simple and require limited data, they are unsuitable for characterising the internal dynamics of a hydrogeological system and/or under conditions where large scale anthropogenic stresses occur within a groundwater basin. Groundwater age modelling, and in particular, the simulation of environmental tracer transport that explicitly accounts for the accumulation and decay of tracer mass, has proven to be highly beneficial in constraining numerical models. Recent improvements in computing power have made numerical simulation of tracer transport feasible. We argue that, unlike directly simulated ages, the results of tracer mass transport simulation can be compared directly to observations, without needing to correct for apparent age bias or other confounding factors.

  7. Organic geochemical constraints on paleoelevation

    Science.gov (United States)

    Polissar, P. J.; Rowley, D. B.; Currie, B. S.; Freeman, K. H.

    2012-12-01

    The elevation history of the land surface is an important factor in the interpretation of past tectonic, climate and ecological processes. However, quantitative estimates of paleoelevation are difficult to produce and new techniques are needed. Organic geochemical approaches to quantifying paleoelevations provide a new perspective on this difficult task. The hydrogen isotopic composition of organic biomarker molecules synthesized by plants and algae is systematically related to the water used for growth. Organic molecules in ancient sediments can provide values for the isotopic composition of this water and thus elevation, provided the relationship between elevation and isotopic values is known. Molecular hydrogen isotope ratios from Cenozoic lake sediments on the Tibetan Plateau demonstrate the utility of a biomarker approach. Terrestrial plant-wax D/H values on Neogene sediments from the Namling-Oiyug Basin provide new paleoelevation estimates that compare well with previous studies. Plant wax D/H ratios paired with lacustrine carbonate oxygen isotope values from the Lunpola and Hoh-Xil basins illustrate how paired isotope systems can unravel the isotopic composition of precipitation from evaporative enrichment of lake waters. A potentially fruitful avenue for future research is illustrated by D/H analyses on older sediments from the Namling-Oiyug Basin. These sediments—like many that could be useful for paleoaltimetry—have experienced significant burial and heating. As temperatures approach the oil window it becomes possible to exchange hydrogen in both the extractable organic molecules (bitumen) and the insoluble organic residue (kerogen). The extent to which this exchange alters the original isotopic composition will determine the usefulness of D/H analyses on thermally mature organic matter. The potential payoff and pitfalls of D/H analyses on heated sediments is illustrated with thermally immature and mature samples from the Namling-Oiyug Basin.

  8. Nonparametric estimation of groundwater residence time distributions: What can environmental tracer data tell us about groundwater residence time?

    Science.gov (United States)

    McCallum, James L.; Engdahl, Nicholas B.; Ginn, Timothy R.; Cook, Peter. G.

    2014-03-01

    Residence time distributions (RTDs) have been used extensively for quantifying flow and transport in subsurface hydrology. In geochemical approaches, environmental tracer concentrations are used in conjunction with simple lumped parameter models (LPMs). Conversely, numerical simulation techniques require large amounts of parameterization and estimated RTDs are certainly limited by associated uncertainties. In this study, we apply a nonparametric deconvolution approach to estimate RTDs using environmental tracer concentrations. The model is based only on the assumption that flow is steady enough that the observed concentrations are well approximated by linear superposition of the input concentrations with the RTD; that is, the convolution integral holds. Even with large amounts of environmental tracer concentration data, the entire shape of an RTD remains highly nonunique. However, accurate estimates of mean ages and in some cases prediction of young portions of the RTD may be possible. The most useful type of data was found to be the use of a time series of tritium. This was due to the sharp variations in atmospheric concentrations and a short half-life. Conversely, the use of CFC compounds with smoothly varying atmospheric concentrations was more prone to nonuniqueness. This work highlights the benefits and limitations of using environmental tracer data to estimate whole RTDs with either LPMs or through numerical simulation. However, the ability of the nonparametric approach developed here to correct for mixing biases in mean ages appears promising.

  9. Using predictive uncertainty analysis to optimise tracer test design and data acquisition

    Science.gov (United States)

    Wallis, Ilka; Moore, Catherine; Post, Vincent; Wolf, Leif; Martens, Evelien; Prommer, Henning

    2014-07-01

    Tracer injection tests are regularly-used tools to identify and characterise flow and transport mechanisms in aquifers. Examples of practical applications are manifold and include, among others, managed aquifer recharge schemes, aquifer thermal energy storage systems and, increasingly important, the disposal of produced water from oil and shale gas wells. The hydrogeological and geochemical data collected during the injection tests are often employed to assess the potential impacts of injection on receptors such as drinking water wells and regularly serve as a basis for the development of conceptual and numerical models that underpin the prediction of potential impacts. As all field tracer injection tests impose substantial logistical and financial efforts, it is crucial to develop a solid a-priori understanding of the value of the various monitoring data to select monitoring strategies which provide the greatest return on investment. In this study, we demonstrate the ability of linear predictive uncertainty analysis (i.e. “data worth analysis”) to quantify the usefulness of different tracer types (bromide, temperature, methane and chloride as examples) and head measurements in the context of a field-scale aquifer injection trial of coal seam gas (CSG) co-produced water. Data worth was evaluated in terms of tracer type, in terms of tracer test design (e.g., injection rate, duration of test and the applied measurement frequency) and monitoring disposition to increase the reliability of injection impact assessments. This was followed by an uncertainty targeted Pareto analysis, which allowed the interdependencies of cost and predictive reliability for alternative monitoring campaigns to be compared directly. For the evaluated injection test, the data worth analysis assessed bromide as superior to head data and all other tracers during early sampling times. However, with time, chloride became a more suitable tracer to constrain simulations of physical transport

  10. Catchment scale tracer testing from karstic features in a porous limestone

    Science.gov (United States)

    Maurice, L.; Atkinson, T. C.; Williams, A. T.; Barker, J. A.; Farrant, A. R.

    2010-07-01

    SummaryTracer testing was undertaken from sinking streams feeding the Chalk, a porous limestone aquifer characterised by frequent small-scale surface karst features. The objective was to investigate the nature and extent of sub-surface karstic development in the aquifer. Previous tracer testing has demonstrated rapid flow combined with low attenuation of tracer. In this study, at two sites rapid groundwater flow was combined with very high attenuation and at two other sites no tracer was detected at springs within the likely catchment area of the stream sinks tested, suggesting that tracer was totally attenuated along the flowpath. It is proposed that the networks beneath stream sinks in the Chalk and other mildly karstic aquifers distribute recharge into multiple enlarged fractures that divide and become smaller at each division whereas the networks around springs have a predominantly tributary topology that concentrates flow into a few relatively large cavities, a morphology with similarities to that of the early stages of karstification. Tracer attenuation is controlled by the degree to which the two networks are directly connected. In the first state, there is no direct linkage and flow between the two networks is via primary fractures in which tracer attenuation is extreme. The second state is at a percolation threshold in which a single direct link joins the two networks. A very small proportion of tracer reaches the spring rapidly but overall attenuation is very high. In the third state, the recharge and discharge networks are integrated therefore a large fraction of tracer reaches the spring and peak concentrations are relatively high. Despite the large number of stream sinks that recharge the Chalk aquifer, these results suggest that sub-surface conduit development may not always be continuous, with flow down smaller fissures and fractures causing high attenuation of solutes and particulates providing a degree of protection to groundwater outlets that is

  11. Single-well "push-pull" partitioning tracer test for NAPL detection in the subsurface.

    Science.gov (United States)

    Istok, Jonathan D; Field, Jennifer A; Schroth, Martin H; Davis, Brian M; Dwarakanath, Varadarajan

    2002-06-15

    Previous environmental applications of partitioning tracer tests to detect and quantify nonaqueous phase liquid (NAPL) contamination in the subsurface have been limited to well-to-well tests. However, theory and numerical modeling suggests that single-well injection-extraction ("push-pull") partitioning tracer tests can also potentially detect and quantify NAPL contamination. In this type of test, retardation factors for injected partitioning tracers are estimated from the increase in apparent dispersion observed in extraction-phase breakthrough curves in the presence of NAPL. A series of laboratory push-pull tests was conducted in physical aquifer models (PAMs) packed with natural aquifer sediment prepared with and without the presence of trichloroethene (TCE) NAPL. Field tests were conducted in an aquifer contaminated with petroleum hydrocarbon NAPL. Injected test solutions contained a suite of partitioning and conservative (nonpartitioning) alcohol tracers. Laboratory push-pull partitioning tracer tests were able to detect and quantify sorption of partitioning tracers to aquifer sediment (in the absence of NAPL) and to detect NAPL when it was present. NAPL saturations computed from estimated retardation factors bracketed those computed from known volumes of emplaced NAPL in the sediment pack. However, numerical modeling with assumed homogeneous NAPL distribution and linear equilibrium partitioning of tracers between aqueous and NAPL phases was unable to reproduce all features of observed breakthrough curves. Excavation of the sediment pack after all tests indicated that a portion of the emplaced NAPL had sunk to the bottom of the PAM invalidating the modeling assumption of homogeneous NAPL distribution. Moreover, the apparent dispersion in extraction-phase breakthrough curves decreased when the injection-extraction pumping rate was decreased, suggesting that mass transfer limitations existed during laboratory tests. Field push-pull partitioning tracer tests were

  12. Glowing clay: Real time tracing using a suite of novel clay based fluorescent tracers

    Science.gov (United States)

    Hardy, Robert; Quinton, John; Pates, Jackie; Coogan, Mike

    2015-04-01

    Clay is one of the most mobile fractions of soil due to its small particle size. It is also known to sorb many chemicals, such as nutrients (notably phosphorus), agrochemicals and heavy metals. The movement of clay is therefore linked with the transport and fate of these substances. A novel fluorescent clay tracing suite has been produced, together with an imaging technique. This suite consists of qualitative clay tracers, using rhodamine based fluorophores, and quantitative clay tracers, using metal based fluorophores. Efforts have also been made to allow integration of commercially available tracers, which are silt and sand sized. The clay tracers exploit the high affinity that montmorillonite has for Rhodamine B and Ru(bpy)3. This allows for an extremely thin layer of the fluorophore to be sorbed onto the clay's surface, in much that same way as materials in the natural environment will bind to clay. The tracer that is produced retains key chemical and physical properties of clay, such as size, shape and density. The retention of these micro-properties results in the retention of macro-properties, such as tendency to aggregate and cracking on drying. Imaging techniques have been developed to analyse these tracers. The imaging system uses diffused laser light to excite the tracer and a modified DSLR camera to image the soil surface. The images have been compiled into a time lapse video showing the movement of clay over the course of a rainfall event. This is the first time that the quantitative movement of clay has been recorded over a soil surface in real time. 4D data can be extracted from the images allowing the spatial location and intensity of tracer to be monitored over time, with mm precision and on the timescale of seconds. As the system can also work with a commercial tracer it is possible to investigate the movement of particles of almost any size and over a range of scales from soil box to hillside. This allows users to access this technique without

  13. Adaptive Multiscale Modeling of Geochemical Impacts on Fracture Evolution

    Science.gov (United States)

    Molins, S.; Trebotich, D.; Steefel, C. I.; Deng, H.

    2016-12-01

    Understanding fracture evolution is essential for many subsurface energy applications, including subsurface storage, shale gas production, fracking, CO2 sequestration, and geothermal energy extraction. Geochemical processes in particular play a significant role in the evolution of fractures through dissolution-driven widening, fines migration, and/or fracture sealing due to precipitation. One obstacle to understanding and exploiting geochemical fracture evolution is that it is a multiscale process. However, current geochemical modeling of fractures cannot capture this multi-scale nature of geochemical and mechanical impacts on fracture evolution, and is limited to either a continuum or pore-scale representation. Conventional continuum-scale models treat fractures as preferential flow paths, with their permeability evolving as a function (often, a cubic law) of the fracture aperture. This approach has the limitation that it oversimplifies flow within the fracture in its omission of pore scale effects while also assuming well-mixed conditions. More recently, pore-scale models along with advanced characterization techniques have allowed for accurate simulations of flow and reactive transport within the pore space (Molins et al., 2014, 2015). However, these models, even with high performance computing, are currently limited in their ability to treat tractable domain sizes (Steefel et al., 2013). Thus, there is a critical need to develop an adaptive modeling capability that can account for separate properties and processes, emergent and otherwise, in the fracture and the rock matrix at different spatial scales. Here we present an adaptive modeling capability that treats geochemical impacts on fracture evolution within a single multiscale framework. Model development makes use of the high performance simulation capability, Chombo-Crunch, leveraged by high resolution characterization and experiments. The modeling framework is based on the adaptive capability in Chombo

  14. SPHRAY: A Smoothed Particle Hydrodynamics Ray Tracer for Radiative Transfer

    CERN Document Server

    Altay, Gabriel; Pelupessy, Inti

    2008-01-01

    We introduce SPHRAY, a Smoothed Particle Hydrodynamics (SPH) ray tracer designed to solve the 3D, time dependent, radiative transfer (RT) equations for arbitrary density fields. The SPH nature of SPHRAY makes the incorporation of separate hydrodynamics and gravity solvers very natural. SPHRAY relies on a Monte Carlo (MC) ray tracing scheme that does not interpolate the SPH particles onto a grid but instead integrates directly through the SPH kernels. Given initial conditions and a description of the sources of ionizing radiation, the code will calculate the non-equilibrium ionization state (HI, HII, HeI, HeII, HeIII, e) and temperature (internal energy/entropy) of each SPH particle. The sources of radiation can include point like objects, diffuse recombination radiation, and a background field from outside the computational volume. The MC ray tracing implementation allows for the quick introduction of new physics and is parallelization friendly. A quick Axis Aligned Bounding Box (AABB) test taken from compute...

  15. Optimal initial condition of passive tracers for their maximal mixing in finite time

    CERN Document Server

    Farazmand, Mohammad

    2016-01-01

    The efficiency of a fluid mixing device is often limited by fundamental laws and/or design constraints, such that a perfectly homogeneous mixture cannot be obtained in finite time. Here, we address the natural corollary question: Given the best available mixer, what is the optimal initial tracer pattern that leads to the most homogeneous mixture after a prescribed finite time? For ideal passive tracers, we show that this optimal initial condition coincides with the right singular vector (corresponding to the smallest singular value) of a suitably truncated Koopman operator. The truncation of the Koopman operator is made under the assumption that there is a small length-scale threshold $\\ell_\

  16. GEOCHEMICAL RECOGNITION OF SPILLED SEDIMENTS USED IN NUMERICAL MODEL VALIDATION

    Institute of Scientific and Technical Information of China (English)

    Jens R.VALEUR; Steen LOMHOLT; Christian KNUDSEN

    2004-01-01

    A fixed link (tunnel and bridge,in total 16 km) was constructed between Sweden and Denmark during 1995-2000.As part of the work,approximately 16 million tonnes of seabed materials (limestone and clay till) were dredged,and about 0.6 million tonnes of these were spilled in the water.Modelling of the spreading and sedimentation of the spilled sediments took place as part of the environmental monitoring of the construction activities.In order to verify the results of the numerical modelling of sediment spreading and sedimentation,a new method with the purpose of distinguishing between the spilled sediments and the naturally occurring sediments was developed.Because the spilled sediments tend to accumulate at the seabed in areas with natural sediments of the same size,it is difficult to separate these based purely on the physical properties.The new method is based on the geo-chemical differences between the natural sediment in the area and the spill.The basic properties used are the higher content of calcium carbonate material in the spill as compared to the natural sediments and the higher Ca/Sr ratio in the spill compared to shell fragments dominating the natural calcium carbonate deposition in the area.The reason for these differences is that carbonate derived from recent shell debris can be discriminated from Danien limestone,which is the material in which the majority of the dredging took place,on the basis of the Ca/Sr ratio being 488 in Danien Limestone and 237 in shell debris.The geochemical recognition of the origin of the sediments proved useful in separating the spilled from the naturally occurring sediments.Without this separation,validation of the modelling of accumulation of spilled sediments would not have been possible.The method has general validity and can be used in many situations where the origin ora given sediment is sought.

  17. Petroleum geochemical proxies for reservoir engineering parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, B. [Petroleum Reservoir Group (PRG), Department of Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, Alberta (Canada); Lager, A. [NRG: School of Civil Engineering and Geosciences, Drummond Building, The University, Newcastle upon Tyne, NE1 7RU (United Kingdom); Potter, D.K.; Buckman, J.O. [Institute of Petroleum Engineering, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS (United Kingdom); Larter, S.R. [Petroleum Reservoir Group (PRG), Department of Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, Alberta (Canada); NRG: School of Civil Engineering and Geosciences, Drummond Building, The University, Newcastle upon Tyne, NE1 7RU (United Kingdom)

    2007-09-15

    The prediction of fluid flow behaviour in petroleum reservoirs is influenced by the physical and chemical processes active in interacting crude oil/brine/rock systems. It is usually not possible to assess these complex systems directly so proxies for molecular scale behaviour are needed. By their very nature, polar non-hydrocarbons are sensitive to fluid-rock interactions, and if properly exploited they may be utilised as proxies for describing reservoir engineering properties (e.g. wettability) that are also sensitive to fluid-rock interactions. We have identified a group of aromatic oxygen (alkylphenols and alkylfluorenones) and aromatic nitrogen (alkylcarbazoles) compounds present in petroleum that appear to respond to variations in fluid-rock properties. Here we describe the chemical and physical changes in a series of core samples obtained from North Sea reservoirs. A number of petrophysical parameters displayed strong correlations with polar non-hydrocarbon occurrence. For example, deflections in gamma ray logs in response to clay content in a coarsening upwards sandstone unit also showed similar deflections from a number of geochemical logs. A core-flood experiment was designed to monitor the chemical and physical changes during oil migration in a siltstone core. Following completion of the core-flood experiment, Environmental Scanning Electron Microscopy (ESEM) analysis of core samples indicated hydrophilic and hydrophobic surface tendencies grading throughout the core. The distributions of polar non-hydrocarbons (e.g. C{sub 0}-C{sub 3}-phenols) appear to correspond closely to the observed wettability alteration. The results confirm the potential for developing proxies for fluid-rock interactions through monitoring the surface active compounds present in the polar non-hydrocarbon fraction of petroleum. (author)

  18. Geochemical Mapping——Evolution of Its Aims, Ideas and Technology

    Institute of Scientific and Technical Information of China (English)

    XIE Xuejing

    2008-01-01

    The development of geochemical mapping progressed from local geochemical prospecting through regional geochemical exploration and regional geochemical mapping to national and global geochemical mapping. This paper discusses the evolution of aims, ideas and methodology of geochemical mapping in Western countries, Russia and China. The sophistication of geochemical mapping methodology will make great contributions to solving resources and environmental problems in the 21st century.

  19. Geologic and geochemical studies of the New Albany Shale Group (Devonian-Mississippian) in Illinois. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bergstrom, R.E.; Shimp, N.F.

    1980-06-30

    The Illinois State Geological Survey is conducting geological and geochemical investigations to evaluate the potential of New Albany Group shales as a source of hydrocarbons, particularly natural gas. Geological studies include stratigraphy and structure, mineralogic and petrographic characterization; analyses of physical properties; and development of a computer-based resources evaluation system. Geochemical studies include organic carbon content and trace elements; hydrocarbon content and composition; and adsorption/desorption studies of gas through shales. Separate abstracts have been prepared for each task reported.

  20. Geochemical Study of Natural CO{sub 2} Emissions in the French Massif Central: How to Predict Origin, Processes and Evolution of CO{sub 2} Leakage; Etude geochimique des emissions naturelles de CO{sub 2} du Massif Central: origine et processus de migration du gaz

    Energy Technology Data Exchange (ETDEWEB)

    Battani, A.; Deville, E.; Faure, J.L.; Jeandel, E.; Noirez, S.; Tocque, E.; Benoit, Y.; Schmitz, J.; Parlouar, D. [Institut francais du petrole, IFP, 92 - Rueil-Malmaison (France); Sarda, P. [Paris-11 Univ., 91 - Orsay (France); Gal, F.; Le Pierres, K.; Brach, M.; Braibant, G.; Beny, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Pokryszka, Z.; Charmoille, A.; Bentivegna, G. [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60 - Verneuil-en-Halatte (France); Pironon, J.; De Donato, P.; Garnier, C.; Cailteau, C.; Barres, O.; Radilla, G.; Bauer, A. [Institut National Polytechnique de Lorraine (INPL), 54 - Vandoeuvre-les-Nancy (France)

    2010-07-15

    This study presents an overview of some results obtained within the French ANR (National Agency of Research) supported Geocarbone-Monitoring research program. The measurements were performed in Sainte-Marguerite, located in the French Massif Central. This site represents a natural laboratory for CO{sub 2}/fluid/rock interactions studies, as well as CO{sub 2} migration mechanisms towards the surface. The CO{sub 2} leaking character of the studied area also allows to test and validate measurements methods and verifications for the future CO{sub 2} geological storage sites. During these surveys, we analyzed soil CO{sub 2} fluxes and concentrations. We sampled and analyzed soil gases, and gas from carbo-gaseous bubbling springs. A one-month continuous monitoring was also tested, to record the concentration of CO{sub 2} both in atmosphere and in the soil at a single point. We also developed a new methodology to collect soil gas samples for noble gas abundances and isotopic analyses, as well as carbon isotopic ratios. Our geochemical results, combined with structural geology, show that the leaking CO{sub 2} has a very deep origin, partially mantle derived. The gas rises rapidly along normal and strike-slip active faults. CO{sub 2} soil concentrations (also showing a mantle derived component) and CO{sub 2} fluxes are spatially variable, and reach high values. The recorded atmospheric CO{sub 2} is not very high, despite the important CO{sub 2} degassing throughout the whole area. (authors)

  1. Geochemical characteristics and geological significance of natural gas in Jinshan area of the Lishu Fault Depression%松辽盆地梨树断陷金山地区天然气地球化学特征及其地质意义

    Institute of Scientific and Technical Information of China (English)

    路清华; 顾忆; 宋振响; 周卓明; 李贶

    2016-01-01

    金山地区位于梨树断陷的东南斜坡带上,是重要的天然气勘探区。通过对金山地区已发现油气藏的天然气地球化学特征研究,认为金山地区天然气有2种不同类型的成因:(1)金2井天然气CO2含量高,为非烃气藏,CO2为无机成因气,烷烃气干燥系数高,为干气,属无机与有机的混合成因气,有机成因气主要为油型气;(2)其余各井天然气非烃含量低,为烷烃气藏,烷烃气中CH4含量较低,为典型湿气,属成熟—高成熟煤型气。%Jinshan area is located in the southeast slope belt of the Lishu Fault Depression, which is an important gas exploration target. The geochemical characteristics of natural gas in Jinshan area indicate that there are two genetic types. (1) In well Jin2, non⁃hydrocarbon gas reservoirs with a high inorganic CO2 content were found. The hydrocarbon gas is featured by a high dryness coefficient. Inorganic gas was mixed with oil associated organic gas. (2) Hydrocarbon gas reservoirs were discovered in the other wells. The gas is coal⁃type wet gas with a high CH4 content, and is mature or over⁃mature.

  2. Blood tracer kinetics in the arterial tree.

    Directory of Open Access Journals (Sweden)

    Elias Kellner

    Full Text Available Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  3. Blood tracer kinetics in the arterial tree.

    Science.gov (United States)

    Kellner, Elias; Gall, Peter; Günther, Matthias; Reisert, Marco; Mader, Irina; Fleysher, Roman; Kiselev, Valerij G

    2014-01-01

    Evaluation of blood supply of different organs relies on labeling blood with a suitable tracer. The tracer kinetics is linear: Tracer concentration at an observation site is a linear response to an input somewhere upstream the arterial flow. The corresponding impulse response functions are currently treated empirically without incorporating the relation to the vascular morphology of an organ. In this work we address this relation for the first time. We demonstrate that the form of the response function in the entire arterial tree is reduced to that of individual vessel segments under approximation of good blood mixing at vessel bifurcations. The resulting expression simplifies significantly when the geometric scaling of the vascular tree is taken into account. This suggests a new way to access the vascular morphology in vivo using experimentally determined response functions. However, it is an ill-posed inverse problem as demonstrated by an example using measured arterial spin labeling in large brain arteries. We further analyze transport in individual vessel segments and demonstrate that experimentally accessible tracer concentration in vessel segments depends on the measurement principle. Explicit expressions for the response functions are obtained for the major middle part of the arterial tree in which the blood flow in individual vessel segments can be treated as laminar. When applied to the analysis of regional cerebral blood flow measurements for which the necessary arterial input is evaluated in the carotid arteries, present theory predicts about 20% underestimation, which is in agreement with recent experimental data.

  4. Fractal tracer distributions in turbulent field theories

    DEFF Research Database (Denmark)

    Hansen, J. Lundbek; Bohr, Tomas

    1998-01-01

    We study the motion of passive tracers in a two-dimensional turbulent velocity field generated by the Kuramoto-Sivashinsky equation. By varying the direction of the velocity-vector with respect to the field-gradient we can continuously vary the two Lyapunov exponents for the particle motion and t...

  5. Suitability of tracers; Eignung von Tracern

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Inst. fuer Hydrologie

    1999-02-01

    Hydrological tracer techniques are a means of making statements on the direction and speed of underground water. One of the simpler tasks is to find out whether there is hydrological communication between two given points. This requires a determination of the direction of flow, which places less exacting demands on the properties of the tracer than does the task of determining the flow velocity of underground water. Tracer methods can serve to infer from flow velocity the distance (flow) velocity, which is defined as the ratio between the distance between two points located in flow direction and the actual time it takes water to flow from one to the other. [Deutsch] Mit Hilfe der hydrologischen Markierungstechniken koennen Aussagen ueber die Richtung und die Geschwindigkeit von Bewegungen des unterirdischen Wassers gemacht werden. Der einfachere Fall liegt vor, wenn festgestellt werden soll, ob zwischen zwei Punkten eine hydrologische Verbindung besteht. Bei dieser Fliessrichtungsbestimmung sind die Forderungen an die Eigenschaften der einzusetzenden Tracer geringer als bei der Bestimmung der Geschwindigkeit des unterirdischen Wassers. Von den Geschwindigkeiten des unterirdischen Wassers ist die Abstands-(Fliess)geschwindigkeit, die definiert ist durch das Verhaeltnis aus dem Abstand und der wahren Fliesszeit zwischen zwei in Bewegungsrichtung gelegenen Punkten, durch Tracermethoden zu bestimmen. (orig.)

  6. Using neural networks to describe tracer correlations

    Directory of Open Access Journals (Sweden)

    D. J. Lary

    2004-01-01

    Full Text Available Neural networks are ideally suited to describe the spatial and temporal dependence of tracer-tracer correlations. The neural network performs well even in regions where the correlations are less compact and normally a family of correlation curves would be required. For example, the CH4-N2O correlation can be well described using a neural network trained with the latitude, pressure, time of year, and methane volume mixing ratio (v.m.r.. In this study a neural network using Quickprop learning and one hidden layer with eight nodes was able to reproduce the CH4-N2O correlation with a correlation coefficient between simulated and training values of 0.9995. Such an accurate representation of tracer-tracer correlations allows more use to be made of long-term datasets to constrain chemical models. Such as the dataset from the Halogen Occultation Experiment (HALOE which has continuously observed CH4  (but not N2O from 1991 till the present. The neural network Fortran code used is available for download.

  7. Travel-time-based thermal tracer tomography

    Science.gov (United States)

    Somogyvári, Márk; Bayer, Peter; Brauchler, Ralf

    2016-05-01

    Active thermal tracer testing is a technique to get information about the flow and transport properties of an aquifer. In this paper we propose an innovative methodology using active thermal tracers in a tomographic setup to reconstruct cross-well hydraulic conductivity profiles. This is facilitated by assuming that the propagation of the injected thermal tracer is mainly controlled by advection. To reduce the effects of density and viscosity changes and thermal diffusion, early-time diagnostics are used and specific travel times of the tracer breakthrough curves are extracted. These travel times are inverted with an eikonal solver using the staggered grid method to reduce constraints from the pre-defined grid geometry and to improve the resolution. Finally, non-reliable pixels are removed from the derived hydraulic conductivity tomograms. The method is applied to successfully reconstruct cross-well profiles as well as a 3-D block of a high-resolution fluvio-aeolian aquifer analog data set. Sensitivity analysis reveals a negligible role of the injection temperature, but more attention has to be drawn to other technical parameters such as the injection rate. This is investigated in more detail through model-based testing using diverse hydraulic and thermal conditions in order to delineate the feasible range of applications for the new tomographic approach.

  8. Soil radon measurements as potential tracer of seismic and volcanic activity at Etna

    Science.gov (United States)

    Neri, Marco; Giammanco, Salvatore; Galli, Gianfranco; Ferrera, Elisabetta

    2014-05-01

    Radon is a radioactive noble gas present in all rocks of the Earth. It's used by the scientific community as a tracer of natural phenomena related to outgassing from the soil along faults, fractures and crustal discontinuity. Recently, radon has also been used on active volcanoes such as Etna, both as a precursor of volcanic phenomena as well as in the study of the dynamics of faults. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) performs discrete and continuous measurements of radon from soil at Etna since 2002. First studies concerned measurements of radon and thoron emissions from soil carried out on the E and SW flanks of Etna, in zones characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds, producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. These studies confirmed that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover. INGV permanent radon monitoring network was installed in July 2005. First results were obtained during the July 2006 eruption. The radon signal recorded at Torre del Filosofo (TdF, ~2950 m asl) was compared with volcanic tremor and thermal radiance data. The onset of explosive activity and a lava fountaining episode were preceded by some hours with increases in radon activity and more gradual increases in volcanic tremor. After 2006, Etna produced dozens of paroxysmal episodes from a new vent opened on the eastern flank of the Southeast Crater (summit area), that have built up a new, huge pyroclastic cone. In many cases we observed increase in radon activity some hours before the eruptive events. These observations suggest that radon emissions from the TdF zone are sensitive to the local geodynamic pressure induced by magma dynamics in the conduit systems. Other promising results were

  9. Tracer injection techniques in flowing surface water

    Science.gov (United States)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed

  10. Halon-1301, a new Groundwater Age Tracer

    Science.gov (United States)

    Beyer, Monique; van der Raaij, Rob; Morgenstern, Uwe; Jackson, Bethanna

    2015-04-01

    Groundwater dating is an important tool to assess groundwater resources in regards to direction and time scale of groundwater flow and recharge and to assess contamination risks and manage remediation. To infer groundwater age information, a combination of different environmental tracers, such as tritium and SF6, are commonly used. However ambiguous age interpretations are often faced, due to a limited set of available tracers and limitations of each tracer method when applied alone. There is a need for additional, complementary groundwater age tracers. We recently discovered that Halon-1301, a water soluble and entirely anthropogenic gaseous substance, may be a promising candidate [Beyer et al, 2014]. Halon-1301 can be determined along with SF6, SF5CF3 and CFC-12 in groundwater using a gas chromatography setup with attached electron capture detector developed by Busenberg and Plummer [2008]. Halon-1301 has not been assessed in groundwater. This study assesses the behaviour of Halon-1301 in water and its suitability as a groundwater age tracer. We determined Halon-1301 in 17 groundwater and various modern (river) waters sites located in 3 different groundwater systems in the Wellington Region, New Zealand. These waters have been previously dated with tritium, CFC-12, CFC-11 and SF6 with mean residence times ranging from 0.5 to over 100 years. The waters range from oxic to anoxic and some show evidence of CFC contamination or degradation. This allows us to assess the different properties affecting the suitability of Halon-1301 as groundwater age tracer, such as its conservativeness in water and local contamination potential. The samples are analysed for Halon-1301 and SF6simultaneously, which allows identification of issues commonly faced when using gaseous tracers such as contamination with modern air during sampling. Overall we found in the assessed groundwater samples Halon-1301 is a feasible new groundwater tracer. No sample indicated significantly elevated

  11. Isotope pattern deconvolution as rising tool for isotope tracer studies in environmental research

    Science.gov (United States)

    Irrgeher, Johanna; Zitek, Andreas; Prohaska, Thomas

    2014-05-01

    During the last decade stable isotope tracers have emerged as versatile tool in ecological research. Besides 'intrinsic' isotope tracers caused by the natural variation of isotopes, the intentional introduction of 'extrinsic' enriched stable isotope tracers into biological systems has gained significant interest. Hereby the induced change in the natural isotopic composition of an element allows amongst others for studying the fate and fluxes of metals, trace elements and species in organisms or provides an intrinsic marker or tag of particular biological samples. Due to the shoreless potential of this methodology, the number of publications dealing with applications of isotope (double) spikes as tracers to address research questions in 'real world systems' is constantly increasing. However, some isotope systems like the natural Sr isotopic system, although potentially very powerful for this type of application, are still rarely used, mainly because their adequate measurement/determination poses major analytical challenges; as e.g. Sr is available in significant amounts in natural samples. In addition, biological systems underlie complex processes such as metabolism, adsorption/desorption or oxidation/reduction. As a consequence, classic evaluation approaches such as the isotope dilution mass spectrometry equation are often not applicable because of the unknown amount of tracer finally present in the sample. Isotope pattern deconvolution (IPD), based on multiple linear regression, serves as simplified alternative data processing strategy to double spike isotope dilution calculations. The outstanding advantage of this mathematical tool lies in the possibility of deconvolving the isotope pattern in a spiked sample without knowing the quantities of enriched isotope tracer being incorporated into the natural sample matrix as well as the degree of impurities and species-interconversion (e.g. from sample preparation). Here, the potential of IPD for environmental tracer

  12. The effects of physical and geochemical heterogeneities on hydro-geochemical transport and effective reaction rates.

    Science.gov (United States)

    Atchley, Adam L; Navarre-Sitchler, Alexis K; Maxwell, Reed M

    2014-09-01

    The role of coupled physical and geochemical heterogeneities in hydro-geochemical transport is investigated by simulating three-dimensional transport in a heterogeneous system with kinetic mineral reactions. Ensembles of 100 physically heterogeneous realizations were simulated for three geochemical conditions: 1) spatially homogeneous reactive mineral surface area, 2) reactive surface area positively correlated to hydraulic heterogeneity, and 3) reactive surface area negatively correlated to hydraulic heterogeneity. Groundwater chemistry and the corresponding effective reaction rates were calculated at three transverse planes to quantify differences in plume evolution due to heterogeneity in mineral reaction rates and solute residence time (τ). The model is based on a hypothetical CO2 intrusion into groundwater from a carbon capture utilization and storage (CCUS) operation where CO2 dissolution and formation of carbonic acid created geochemical dis-equilibrium between fluids and the mineral galena that resulted in increased aqueous lead (Pb(2+)) concentrations. Calcite dissolution buffered the pH change and created conditions of galena oversaturation, which then reduced lead concentrations along the flow path. Near the leak kinetic geochemical reactions control the release of solutes into the fluid, but further along the flow path mineral solubility controls solute concentrations. Simulation results demonstrate the impact of heterogeneous distribution of geochemical reactive surface area in coordination with physical heterogeneity on the effective reaction rate (Krxn,eff) and Pb(2+) concentrations within the plume. Dissimilarities between ensemble Pb(2+) concentration and Krxn,eff are attributed to how geochemical heterogeneity affects the time (τeq) and therefore advection distance (Leq) required for the system to re-establish geochemical equilibrium. Only after geochemical equilibrium is re-established, Krxn,eff and Pb(2+) concentrations are the same for all

  13. Geochemical processes at a fresh/seawater interface in a shallow sandy aquifer

    DEFF Research Database (Denmark)

    Andersen, Martin Søgaard; Iversen, Vibeke Margrethe Nyvang; Postma, Diederik Jan

    2001-01-01

    Chemical processes in a natural fresh-/seawater mixing zone were studied in a shallow sandy aquifer. The dominant redox-processes are sulfate reduction and methanogenesis. Methanogenesis produces CO2, which causes calcite dissolution. The produced calcium induces ion exchange with sodium. The final...... result of these interactions between different types of geochemical processes is an anoxic groundwater enriched in bicarbonate and sodium....

  14. Comparison of Heat and Bromide as Ground Water Tracers Near Streams

    Science.gov (United States)

    Constantz, J.; Cox, M.H.; Su, G.W.

    2003-01-01

    Heat and bromide were compared as tracers for examining stream/ground water exchanges along the middle reaches of the Santa Clara River, California, during a 10-hour surface water sodium bromide injection test. Three cross sections that comprise six shallow (sodium bromide injection test. Vertical, one-dimensional simulations of bromide concentrations in the sediments yielded a good match to the observed bromide concentrations, without adjustment of any model parameters except solute dispersivities. This indicates that, for the spatial and temporal scales examined on the Santa Clara River, the use of heat and bromide as tracers provide comparable information with respect to apparent hydraulic conductivities and fluxes for sediments near streams. In other settings, caution should be used due to differences in the nature of conservative (bromide) versus nonconservative (heat) tracers, particularly when preferential flowpaths are present.

  15. Use of thorium as tracer on study of groundwater of Botucatu sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Paulo Augusto d' A.; Menezes, Maria Angela B.C. de; Moreira, Rubens Martins; Reis Junior, Aluisio Souza; Kastner, Geraldo Frederico, E-mail: paap@cdtn.br, E-mail: menezes@cdtn.br, E-mail: rubens@cdtn.br, E-mail: reisas@cdtn.br, E-mail: gfk@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Thorium in some mineral compounds is very difficult to be dissolved in aqueous medium. To study the mobility of thorium in water, one alternative is to complex this element with EDTA, becoming possible to follow the behavior of thorium this medium. This way, in groundwater with low natural radioactivity and low {sup 232}Th activity, thorium can be used as a tracer. This paper describes the application of the complex Th-EDTA as a tracer applying the solution trough a sandstone sample made by rock from Botucatu Sandstone. The objective was to simulate the flow of groundwater inside the original rock aiming at future use of rare-earth elements complexed with EDTA as tracer. Alpha spectrometry technique was used to determine {sup 232}Th in the water samples with {sup 230}Th as inner-standard. (author)

  16. Laplace transform in tracer kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, Eliete B., E-mail: eliete@pucrs.br [Instituto do Cerebro (InsCer/FAMAT/PUC-RS), Porto Alegre, RS, (Brazil). Faculdade de Matematica

    2013-07-01

    The main objective this paper is to quantify the pharmacokinetic processes: absorption, distribution and elimination of radiopharmaceutical(tracer), using Laplace transform method. When the drug is administered intravenously absorption is complete and is available in the bloodstream to be distributed throughout the whole body in all tissues and fluids, and to be eliminated. Mathematical modeling seeks to describe the processes of distribution and elimination through compartments, where distinct pools of tracer (spatial location or chemical state) are assigned to different compartments. A compartment model is described by a system of differential equations, where each equation represents the sum of all the transfer rates to and from a specific compartment. In this work a two-tissue irreversible compartment model is used for description of tracer, [{sup 18}F]2-fluor-2deoxy-D-glucose. In order to determine the parameters of the model, it is necessary to have information about the tracer delivery in the form of an input function representing the time-course of tracer concentration in arterial blood or plasma. We estimate the arterial input function in two stages and apply the Levenberg-Marquardt Method to solve nonlinear regressions. The transport of FDG across de arterial blood is very fast in the first ten minutes and then decreases slowly. We use de Heaviside function to represent this situation and this is the main contribution of this study. We apply the Laplace transform and the analytical solution for two-tissue irreversible compartment model is obtained. The only approach is to determinate de arterial input function. (author)

  17. The geochemical atlas of Alaska, 2016

    Science.gov (United States)

    Lee, Gregory K.; Yager, Douglas B.; Mauk, Jeffrey L.; Granitto, Matthew; Denning, Paul D.; Wang, Bronwen; Werdon, Melanie B.

    2016-06-21

    A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska; careful treatment of such data may provide significant and revealing geochemical maps that may be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas. To maximize the spatial density and extent of data coverage for statewide mapping of element distributions, we compiled and integrated analyses of more than 175,000 sediment and soil samples from three major, separate sources: the U.S. Geological Survey, the National Uranium Resource Evaluation program, and the Alaska Division of Geological & Geophysical Surveys geochemical databases. Various types of heterogeneity and deficiencies in these data presented major challenges to our development of coherently integrated datasets for modeling and mapping of element distributions. Researchers from many different organizations and disparate scientific studies collected samples that were analyzed using highly variable methods throughout a time period of more than 50 years, during which many changes in analytical techniques were developed and applied. Despite these challenges, the U.S. Geological Survey has produced a new systematically integrated compilation of sediment and soil geochemical data with an average sample site density of approximately 1 locality per 10 square kilometers (km2) for the entire State of Alaska, although density varies considerably among different areas. From that compilation, we have modeled and mapped the distributions of 68 elements, thus creating an updated geochemical atlas for the State.

  18. The effects of sorting by aeolian processes on the geochemical characteristics of surface materials: a wind tunnel experiment

    Science.gov (United States)

    Wang, Xunming; Lang, Lili; Hua, Ting; Zhang, Caixia; Li, Hui

    2017-03-01

    The geochemical characteristics of aeolian and surface materials in potential source areas of dust are frequently employed in environmental reconstructions as proxies of past climate and as source tracers of aeolian sediments deposited in downwind areas. However, variations in the geochemical characteristics of these aeolian deposits that result from near-surface winds are currently poorly understood. In this study, we collected surface samples from the Ala Shan Plateau (a major potential dust source area in Central Asia) to determine the influence of aeolian processes on the geochemical characteristics of aeolian transported materials. Correlation analyses show that compared with surface materials, the elements in transported materials (e.g., Cu, As, Pb, Mn, Zn, Al, Ca, Fe, Ga, K, Mg, P, Rb, Co, Cr, Na, Nb, Si, and Zr) were subjected to significant sorting by aeolian processes, and the sorting also varied among different particle size fractions and elements. Variations in wind velocity were significantly correlated with the contents of Cr, Ga, Sr, Ca, Y, Nd, Zr, Nb, Ba, and Al, and with the Zr/Al, Zr/Rb, K/Ca, Sr/Ca, Rb/Sr, and Ca/Al ratios. Given the great variation in the geochemical characteristics of materials transported under different aeolian processes relative to those of the source materials, these results indicate that considerable uncertainty may be introduced to analyses by using surface materials to trace the potential source areas of aeolian deposits that accumulate in downwind areas.

  19. An inexpensive field fluorometer for hydrogeological tracer tests with three tracers and turbidity measurement

    OpenAIRE

    Schnegg, Pierre-André

    2005-01-01

    The Geomagnetism Group of the University of Neuchâtel has recently designed a flow-through field fluorometer with added spectral capabilities for hydrological tracer tests. This instrument is equipped with four optical axes allowing water sample illumination with four independent light sources at different wavelenghs covering the full spectrum from UV to red. As many as three conveniently selected (dye) tracers can be simultaneously measured and separeted from a cocktail. Careful turbidity me...

  20. EVALUATION OF LEAKAGE FROM FUME HOODS USING TRACER GAS, TRACER NANOPARTICLES AND NANOPOWDER HANDLING TEST METHODOLOGIES

    OpenAIRE

    Dunn, Kevin H.; Tsai, Candace Su-Jung; Woskie, Susan R.; Bennett, James S.; Garcia, Alberto; Ellenbecker, Michael J.

    2014-01-01

    The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tr...

  1. Study on a Cosmic-ray-produced Silicon-32 as a Tracer for Ocean Processes

    Directory of Open Access Journals (Sweden)

    ZHOU Peng

    2015-01-01

    Full Text Available The isotope silicon-32, with a half-life of approximately 150 years, is a cosmic-ray-produced radioactive nuclide in the atmosphere. Due to its single source and the relatively constant production rate, silicon-32 with its chemical and biological characteristics like the other stable silicon isotopes always has been seen as an ideal clock and tracer which has the potential to fill the dating time-gap and to understand marine from 50 to 1 000 years geochemical-geophysical processes, e.g. the seawater mixing process in offshore and ocean, the geochemistry and cycle of silica in estuary and ocean, the particles mixing process in the deep sea bed, as well as the estimation of the sediment deposition rate and the establishment of the time-sequence to reflect the past marine environmental changes.

  2. PET tracers for somatostatin receptor imaging of neuroendocrine tumors

    DEFF Research Database (Denmark)

    Johnbeck, Camilla Bardram; Knigge, Ulrich; Kjær, Andreas

    2014-01-01

    Neuroendocrine tumors have shown rising incidence mainly due to higher clinical awareness and better diagnostic tools over the last 30 years. Functional imaging of neuroendocrine tumors with PET tracers is an evolving field that is continuously refining the affinity of new tracers in the search...... these PET tracers further....

  3. Acupuncture meridians demythified. A study using the radioactive tracer method

    Energy Technology Data Exchange (ETDEWEB)

    Simon, J.; Esquerre, J.P.; Guiraud, R.; Guiraud, G.; Lazorthes, Y.

    1988-07-01

    Radioactive trajectories can be visualized by injecting a radioactive tracer, technetium 99 m, at the site of acupuncture points. To determine the exact nature of these trajectories we performed several experiments on healthy volunteers, and our results may be summarized as follows. The target organs of technetium 99 m, and notably the thyroid gland, were always visualized. The circulating radioactivity, visible on scintiscans and confirmed by venous blood counts, was not negligible. The radioactive trajectories we observed were often divided at their starting point and did not extend along the whole length of the acupuncture meridians they might have made visible. The radioactive trajectories disappeared after venous blockade to reappear when the blockade was lifted. Finally, the radioactive trajectories obtained were very similar after injection at the acupuncture point and at a control point. These findings indicate a lymphatic and venous drainage of the radioactive tracer at the site of injection followed by transportation through the veins, rather than visualization of acupuncture meridians as suggested by some authors.

  4. Geochemical Interactions and Viral-Prokaryote Relationships in Freshwater Environments

    Science.gov (United States)

    Kyle, J. E.; Ferris, G.

    2009-05-01

    Viral and prokaryotic abundances were surveyed throughout southern Ontario aquatic habitats to determine relationships with geochemical parameters in the natural environment. Surface water samples were collected from acid mine drainage in summer of 2007 and 2008 and from circum-neutral pH environments in October to November 2008. Site determination was based on collecting samples from various aquatic habitats (acid mine drainage, lakes, rivers, tributaries, wetlands) with differing bedrock geology (limestone and shale dominated vs granitic Canadian Shield) to obtain a range of geochemical conditions. At each site, measurements of temperature, pH, and Eh were conducted. Samples collected for microbial counts and electron imaging were preserved to a final concentration of 2.5 % (v/v) glutaraldehyde. Additional sample were filtered into 60 mL nalgene bottles and amber EPA certified 40 mL glass vials to determine chemical constituents and dissolved organic carbon (DOC), respectively. Water was also collected to determine additional physiochemical parameters (dissolved total iron, ferric iron, nitrate, sulfate, phosphate, alkalinity, and turbidity). All samples were stored at 4 °C until analysis. Viral and prokaryotic abundance was determined by staining samples with SYBR Green I and examining with a epifluorescence microscope under blue excitation. Multiple regression analysis using stepwise backwards regression and general linear models revealed that viral abundance was the most influential predictor of prokaryotic abundance. Additional predictors include pH, sulfate, phosphate, and magnesium. The strength of the model was very strong with 90 % of the variability explained (R2 = 0.90, p multicollinearity with sulfate, iron was removed from the model (as sulfate acts more conservatively across the range of pH sampled, 2.5-9.0). Geochemical variables that have been reported to influence viral abundances under laboratory and field experiments (i.e. Ca2+, DOC

  5. Compilation of kinetic data for geochemical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.C. [Monitor Scientific, LLC., Denver, Colorado (United States); Savage, D. [Quintessa, Ltd., Nottingham (United Kingdom); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works

    2000-01-01

    Kinetic data, including rate constants, reaction orders and activation energies, are compiled for 34 hydrolysis reactions involving feldspars, sheet silicates, zeolites, oxides, pyroxenes and amphiboles, and for similar reactions involving calcite and pyrite. The data are compatible with a rate law consistent with surface reaction control and transition-state theory, which is incorporated in the geochemical software package EQ3/6 and GWB. Kinetic data for the reactions noted above are strictly compatible with the transition-state rate law only under far-from-equilibrium conditions. It is possible that the data are conceptually consistent with this rate law under both far-from-equilibrium and near-to-equilibrium conditions, but this should be confirmed whenever possible through analysis of original experimental results. Due to limitations in the availability of kinetic data for mine-water reactions, and in order to simplify evaluations of geochemical models of groundwater evolution, it is convenient to assume local-equilibrium in such models whenever possible. To assess whether this assumption is reasonable, a modeling approach accounting for couple fluid flow and water-rock interaction is described that can be use to estimate spatial and temporal scale of local equilibrium. The approach is demonstrated for conditions involving groundwater flow in fractures at JNC's Kamaishi in-situ tests site, and is also used to estimate the travel time necessary for oxidizing surface waters to migrate to the level of a HLW repository in crystalline rock. The question of whether local equilibrium is a reasonable assumption must be addressed using an appropriate modeling approach. To be appropriate for conditions at the Kamaishi site using the modeling approach noted above, the fracture fill must closely approximate a porous mine, groundwater flow must be purely advective and diffusion of solutes across the fracture-host rock boundary must not occur. Moreover, the

  6. Geochemical research of soil and attic dust in Litija area, Slovenia

    Directory of Open Access Journals (Sweden)

    Mateja Jemec

    2007-12-01

    Full Text Available Geochemical research was carried as part of the environmental research project at the Geological Survey of Slovenia. The aim of the project was to determine the impact on the environment caused by heavy metals released in the environment during mining and smeltingactivity in the area of Litija. The samples of attic dust and soil (0–5 cm were examined with the view to separate the natural distribution of chemical elements in the environment from the one caused by past mining and smelting activities. Based on chemically analyses we determine two main geochemical associations and their spatial distribution. First geochemical association (Al, Co, Ce, K, La, Li, Nb, Rb, Sc, Ta, Th in Ti is influencedmainlybynatural source, the second man-made association (As, Cd, Hg, Pb, Sb, Sn in Zn is caused mainly because of mining and lead smelting.

  7. Community-Based Development of Standards for Geochemical and Geochronological Data

    Science.gov (United States)

    Lehnert, K. A.; Walker, D.; Vinay, S.; Djapic, B.; Ash, J.; Falk, B.

    2007-12-01

    The Geoinformatics for Geochemistry (GfG) Program (www.geoinfogeochem.org) and the EarthChem project (www.earthchem.org) aim to maximize the application of geochemical data in Geoscience research and education by building a new advanced data infrastructure for geochemistry that facilitates the compilation, communication, serving, and visualization of geochemical data and their integration with the broad Geoscience data set. Building this new data infrastructure poses substantial challenges that are primarily cultural in nature, and require broad community involvement in the development and implementation of standards for data reporting (e.g., metadata for analytical procedures, data quality, and analyzed samples), data publication, and data citation to achieve broad acceptance and use. Working closely with the science community, with professional societies, and with editors and publishers, recommendations for standards for the reporting of geochemical and geochronological data in publications and to data repositories have been established, which are now under consideration for adoption in journal and agency policies. The recommended standards are aligned with the GfG and EarthChem data models as well as the EarthChem XML schema for geochemical data. Through partnerships with other national and international data management efforts in geochemistry and in the broader marine and terrestrial geosciences, GfG and EarthChem seek to integrate their development of geochemical metadata standards, data format, and semantics with relevant existing and emerging standards and ensure compatibility and compliance.

  8. Tracer Diffusion Mechanism in Amorphous Solids

    Directory of Open Access Journals (Sweden)

    P. K. Hung

    2011-01-01

    Full Text Available Tracer diffusion in amorphous solid is studied by mean of nB-bubble statistic. The nB-bubble is defined as a group of atoms around a spherical void and large bubble that represents a structural defect which could be eliminated under thermal annealing. It was found that amorphous alloys such as CoxB100−x (x=90, 81.5 and 70 and Fe80P20 suffer from a large number of vacancy bubbles which function like diffusion vehicle. The concentration of vacancy bubble weakly depends on temperature, but essentially on the relaxation degree of considered sample. The diffusion coefficient estimated for proposed mechanism via vacancy bubbles is in a reasonable agreement with experiment for actual amorphous alloys. The relaxation effect for tracer diffusion in amorphous alloys is interpreted by the elimination of vacancy bubbles under thermal annealing.

  9. A Investigation of Partially Extracted Tracers Used to Determine Myocardial Blood Flow with PET.

    Science.gov (United States)

    Christian, Bradley Thomas

    Positron Emission Tomography (PET) provides the ability to quantitatively measure mass-specific blood flow to myocardial tissue (ml/min/g tissue). The partially extracted tracers ^{62}Cu -PTSM and two single photon emission computed tomography(SPECT) agents, teboroxime and sestamibi were studied. The latter two demonstrate the effectiveness of PET as a pharmacological tool for SPECT perfusion tracer development. The characteristics of these tracers were compared to commonly used partially extracted tracers ^{13}rm NH_3 and ^{82} Rb. Positron emitting ^{rm 94m}Tc was used to label ligands originally developed for ^{rm 99m} Tc labeling. ^{rm 94m }Tc can be produced by the bombardment of a natural molybdenum foil with an 11Mev proton beam, via the ^{94}rm Mo(p,n)^ {94m}Tc reaction. The production of ^{rm94m}Tc is accompanied by ^{92}Tc, ^ {94}Tc, ^{95} Tc, ^{rm 95m}Tc, ^{96}Tc, and ^{rm 99m}Tc due to the isotopic mixture of natural Mo. The presence of these radionuclidic impurities increase the radiation dose received by the patient and radio chemist. The elimination of these impurities was achieved by irradiating an isotopically enriched target material, ^{94}rm MoO_3. The ability to reclaim the enriched target is essential due to the high cost of the material. Recovery was accomplished by a solvent extraction technique yielding an activity recovery of 80% and target material recovery of 95%. Preliminary data was measured for the myocardial perfusion tracer ^{62}Cu -PTSM. It was found that the uptake of ^ {62}Cu-PTSM is linear for resting flows but a high degree of variability is observed at stress induced flows. This same result was found in the human studies when compared to ^{13} rm NH_3 measured myocardial perfusion values. The dynamic analysis of multiple tracers in the sequence of protocols: (1) acute canine prep ( ^{11}rm CO, ^{82 }Rb, ^{62}Cu-PTSM, ^{13}rm NH_3, ^{94m,99m}Tc-BATO, H_2 ^{14}rm O, ^{18 }FCH_3), (2) chronic canine prep ( ^{82}rm Rb, ^{13 }NH_3

  10. The medical applications of radioactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.G.

    1947-12-31

    This report provides a broad yet in depth overview of the use of radioactive materials as tracers in medicine and biology for the period of 1935--1947. Particular attention is paid to is of radio-sodium, radio-iodine, radio-iron, radio-phosphorus, radio-strontium, and fission products. The main thrust of this paper is human rather than animal work and focuses in work that has been published.

  11. Molecules as tracers of galaxy evolution

    DEFF Research Database (Denmark)

    Costagliola, F.; Aalto, S.; I. Rodriguez, M.;

    2011-01-01

    We investigate the molecular gas properties of a sample of 23 galaxies in order to find and test chemical signatures of galaxy evolution and to compare them to IR evolutionary tracers. Observation at 3 mm wavelengths were obtained with the EMIR broadband receiver, mounted on the IRAM 30 m telesco...... detect the molecule in its vibrationally excited state.We find low HNC/HCN line ratios (...

  12. Tracer technology modeling the flow of fluids

    CERN Document Server

    Levenspiel, Octave

    2012-01-01

    A vessel’s behavior as a heat exchanger, absorber, reactor, or other process unit is dependent upon how fluid flows through the vessel.  In early engineering, the designer would assume either plug flow or mixed flow of the fluid through the vessel.  However, these assumptions were oftentimes inaccurate, sometimes being off by a volume factor of 100 or more.  The result of this unreliable figure produced ineffective products in multiple reaction systems.   Written by a pioneering researcher in the field of chemical engineering, the tracer method was introduced to provide more accurate flow data.  First, the tracer method measured the actual flow of fluid through a vessel.  Second, it developed a suitable model to represent the flow in question.  Such models are used to follow the flow of fluid in chemical reactors and other process units, like in rivers and streams, or solid and porous structures.  In medicine, the tracer method is used to study the flow of chemicals—harmful  and harmless—in the...

  13. The environmental behaviour of beryllium-7; implications for its use as a soil erosion tracer

    Science.gov (United States)

    Taylor, A.; Blake, W. H.; Keith-Roach, M. J.; Couldrick, L.

    2010-05-01

    Beryllium-7 is a cosmogenic fallout radionuclide (FRN) that can be employed as a tracer in soil erosion studies. Owing to its short half-life (53.3 days), estimates of soil redistribution from a single event or wet season can be derived, complimenting medium-term 137Cs-based data. The ability of 7Be to provide robust quantification of soil erosion over short timescales is vital when considering the potential for climate change to influence precipitation patterns and shifts in landuse. A major requirement of the technique is the capacity of the FRN to adsorb to soil particles and remain bound during transport. To date, little attention has been given to the geochemical behaviour of 7Be. The research reported here aims to develop knowledge of 7Be adsorption behaviour in a range of soil types and environmental conditions to support its use as a tracer at the catchment-scale. Four agricultural soils common to south Devon, UK were selected for experiments designed to investigate7Be solid-phase partitioning in soils and tracer stability under changing environmental conditions. Preliminary results from two key aspects of the work are presented here. The BCR three-step sequential extraction procedure was adopted to determine 7Be adsorption to operationally-defined soil fractions. Early findings indicate that 7Be is largely associated with Fe/Mn fractions with up to 67% adsorbed to this reducible phase. This supports the use of 7Be as a soil erosion tracer at the slope-scale but may have implications for 7Be mobility under reducing conditions in deposition zones. In addition, batch experiments have been undertaken to evaluate 7Be behaviour in the dissolved phase focussing upon the role of DOC as a complexing agent in soil solutions since soil solution DOC can increase following manure and compost application. Results will underpin the use of 7Be as a sediment tracer within an Interreg IVA funded research programme addressing wetland restoration as a catchment management

  14. The environmental behaviour of beryllium-7: implications for its use as a soil erosion tracer

    Science.gov (United States)

    Taylor, A.; Blake, W. H.; Keith-Roach, M. J.; Couldrick, L.

    2010-05-01

    Beryllium-7 is a cosmogenic fallout radionuclide (FRN) that can be employed as a tracer in soil erosion studies. Owing to its short half life (53.3 days), estimates of soil redistribution from a single event or wet season can be derived, complimenting medium-term 137Cs-based data. The ability of 7Be to provide robust quantification of soil erosion over short timescales is vital when considering the potential for climate change to influence precipitation patterns and shifts in landuse. A major requirement of the technique is the capacity of the FRN to adsorb to soil particles and remain bound during transport. To date, little attention has been given to the geochemical behaviour of 7Be. The research reported here aims to develop knowledge of 7Be adsorption behaviour in a range of soil types and environmental conditions to support its use as a tracer at the catchment scale. Four agricultural soils common to south Devon, UK were selected for experiments designed to investigate7Be solid-phase partitioning in soils and tracer stability under changing environmental conditions. Preliminary results from two key aspects of the work are reported here. The BCR three-step sequential extraction procedure was adopted to investigate 7Be adsorption to operationally-defined soil fractions. Early findings indicate that 7Be is largely associated with Fe/Mn fractions with up to 67% adsorbed to this reducible phase. This supports the use of 7Be as a soil erosion tracer at the slope-scale but may have implications for 7Be mobility under reducing conditions in deposition zones. In addition, batch experiments have been undertaken to evaluate 7Be behaviour in the dissolved phase focusing upon the role of DOC as a complexing agent in soil solutions since soil solution DOC can increase following manure and compost application. Results will be used to underpin the application of 7Be as a sediment tracer within an Interreg IVA funded research programme addressing wetland restoration as a

  15. Urban geochemical mapping : essential information for redevelopment

    OpenAIRE

    Fordyce, Fiona; Ferguson, Alex; Shaw, Richard; Baldock, John

    1999-01-01

    Cost-effective fit-for-purpose redevelopment of brownfield sites requires both regional and local information on the physical and chemical states of the near-surface environment. The BGS G-BASE programme is providing baseline/benchmark geochemical data for both rural and urban areas based on the collection of stream sediment, stream water and soil samples.

  16. Identification of Geochemical Anomaly by Multifractal Analysis

    Institute of Scientific and Technical Information of China (English)

    Xie Shuyun; Cheng Qiuming; Ke Xianzhong; Bao Zhengyu; Wang Changming; Quan Haoli

    2008-01-01

    The separation of anomalies from geochemical background is an important part of data analysis because lack of such identifications might have profound influence on or even distort the final analysis results. In this article, 1 672 geochemical analytical data of 11 elements, including Cu, Mo, Ag, Sn, and others, from a region within Tibet, South China, are used as one example. Together with the traditional anomaly recognition method of using the iterative mean ±2σ, local multifractality theory has been utilized to delineate the ranges of geochemical anomalies of the elements. To different degrees, on the basis of original data mapping, C-A fractal analysis and singularity exponents, Sn differs from the other 10 elements. Moreover, geochemical mapping results based on values of the multifractal asymmetry index for all elements delineate the highly anomalous area. Similar to other 10 elements, the anomalous areas of Sn delineated by the asymmetry index distribute along the main structure orientations. According to the asymmetry indexes, the 11 elements could be classified into 3 groups: (1) Ag and Au, (2) As-Sb-Cu-Pb-Zn-Mo, and (3) Sn-Bi-W.This paragenetic association of elements can be used to interpret possible origins of mineralization, which is in agreement with petrological analysis and field survey results.

  17. Metallogenetic and geochemical provinces : book review

    NARCIS (Netherlands)

    Schuiling, R.D.

    1975-01-01

    In November 1972 a symposium on metallogenetic and geochemical provinces was organized in Leoben by Prof. W.E. Petrascheck; the proceedings of this symposium have now appeared. The book is recommended to all those who want to combine their interest in economic geology with a somewhat wider

  18. Metallogenetic and geochemical provinces : book review

    NARCIS (Netherlands)

    Schuiling, R.D.

    1975-01-01

    In November 1972 a symposium on metallogenetic and geochemical provinces was organized in Leoben by Prof. W.E. Petrascheck; the proceedings of this symposium have now appeared. The book is recommended to all those who want to combine their interest in economic geology with a somewhat wider outlook i

  19. Application of environmental groundwater tracers at the Sulphur Bank Mercury Mine, California, USA

    Science.gov (United States)

    Engle, M.A.; Goff, F.; Jewett, D.G.; Reller, G.J.; Bauman, J.B.

    2008-01-01

    Boron, chloride, sulfate, ??D, ??18O, and 3H concentrations in surface water and groundwater samples from the Sulphur Bank Mercury Mine (SBMM), California, USA were used to examine geochemical processes and provide constraints on evaporation and groundwater flow. SBMM is an abandoned sulfur and mercury mine with an underlying hydrothermal system, adjacent to Clear Lake, California. Results for non-3H tracers (i.e., boron, chloride, sulfate, ??D, and ??18O) identify contributions from six water types at SBMM. Processes including evaporation, mixing, hydrothermal water input and possible isotopic exchange with hydrothermal gases are also discerned. Tritium data indicate that hydrothermal waters and other deep groundwaters are likely pre-bomb (before ???1952) in age while most other waters were recharged after ???1990. A boron-based steady-state reservoir model of the Herman Impoundment pit lake indicates that 71-79% of its input is from meteoric water with the remainder from hydrothermal contributions. Results for groundwater samples from six shallow wells over a 6-month period for ??D and ??18O suggests that water from Herman Impoundment is diluted another 3% to more than 40% by infiltrating meteoric water, as it leaves the site. Results for this investigation show that environmental tracers are an effective tool to understand the SBMM hydrogeologic regime. ?? Springer-Verlag 2007.

  20. Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media

    Science.gov (United States)

    Granitto, Matthew; Bailey, Elizabeth A.; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.

    2011-01-01

    The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons

  1. Geochemical Mapping of 4 Vesta Begins

    Science.gov (United States)

    Prettyman, Thomas H.; Feldman, William C.; Forni, Olivier; Joy, Steven P.; Lawrence, David J.; LeCorre, Lucille; Mafi, Joseph N.; McCord, Thomas B.; McCoy, Timothy J.; McSween, Harry Y.; Middlefehldt, David W.; Polanskey, Carol; Rayman, Marc; Raymond, Carol A.; Reddy, Vishnu; Reedy, Robert C.; Russell, Christopher T.; Titus, Timothy N.; Toplis, Mike J.

    2011-01-01

    By December, the NASA Dawn spacecraft will have descended to a low altitude mapping orbit (LAMO), where the Gamma Ray and Neutron Detector (GRaND) will acquire global mapping data for up to four months. Measurements by GRaND will help answer elusive questions about how Vesta differentiated and the nature of processes that shaped Vesta s surface. The data will be analyzed to determine the abundances of Mg, Si, Fe, K, Th, and H at a spatial resolution of roughly 300 km full-width-at-half-maximum from a 465 km radius orbit. Thermal and fast neutron counting data will be analyzed to determine the neutron macroscopic absorption cross section and average atomic mass, providing constraints on additional elements, such as Ca and Al. GRaND will quantify the elemental composition of coarse spatial units identified by Dawn s Framing Camera (FC) and the Visible & Infrared Spectrometer (VIR). In addition, GRaND will map the mixing ratio of compositional end members selected from the howardite, eucrite and diogenite (HED) meteorites, determine the relative proportions of plagioclase and mafic minerals, and search for compositions that are absent or under-represented in the meteorite collection. While it is generally thought that Vesta s crust on a regional scale should be well-represented by linear mixing of HED whole-rock compositions, there are hints that Vesta may be more diverse than implied by this model. For example, the discovery of K-rich impact glasses in howardites suggests that K-rich rocks may be present on a portion of Vesta s surface, and the analysis of diogenites indicates considerable variability in the magmatic processes that formed them. The chemical composition of materials within Vesta s south polar structure may provide further clues to how it formed. An impact might have exposed mantle and lower crustal materials, which should have a distinctive compositional signature. We present the analysis of data acquired by GRaND from cruise through the descent to

  2. Environmental tracers for elucidating the weathering process in a phosphogypsum disposal site: Implications for restoration

    Science.gov (United States)

    Pérez-López, Rafael; Nieto, José M.; de la Rosa, Jesús D.; Bolívar, Juan P.

    2015-10-01

    This study provides geochemical data with the aim of identifying and tracing the weathering of phosphogypsum wastes stack-piled directly on salt-marshes of the Tinto River (Estuary of Huelva, SW Spain). With that purpose, different types of highly-polluted acid solutions were collected in the stack. Connection between these solutions and the estuarine environment was studied by geochemical tracers, such as rare earth elements (REE) and their North American Shale Composite (NASC)-normalized patterns and Cl/Br ratios. Phosphogypsum-related wastewaters include process water stored on the surface, pore-water contained in the phosphogypsum profile and edge outflow water emerging from inside the stack. Edge outflow waters are produced by waterlogging at the contact between phosphogypsum and the nearly impermeable marsh surface and discharge directly into the estuary. Process water shows geochemical characteristics typical of phosphate fertilizers, i.e. REE patterns with an evident enrichment of heavy-REE (HREE) with respect to middle-REE (MREE) and light-REE (LREE). By contrast, REE patterns of deeper pore-water and edge outflows are identical to those of Tinto River estuary waters, with a clear enrichment of MREE relative to LREE and HREE denoting influence of acid mine drainage. Cl/Br ratios of these solutions are very close to that of seawater, which also supports its estuarine origin. These findings clearly show that process water is not chemically connected with edge outflows through pore-waters, as was previously believed. Phosphogypsum weathering likely occurs by an upward flow of seawater from the marsh because of overpressure and permeability differences. Several recommendations are put forward in this study to route restoration actions, such as developing treatment systems to improve the quality of the edge outflow waters before discharging to the receiving environment.

  3. Geobiochemistry: Placing Biochemistry in Its Geochemical Context

    Science.gov (United States)

    Shock, E.; Boyer, G. M.; Canovas, P. A., III; Prasad, A.; Dick, J. M.

    2014-12-01

    Goals of geobiochemistry include simultaneously evaluating the relative stabilities of microbial cells and minerals, and predicting how the composition of biomolecules can change in response to the progress of geochemical reactions. Recent developments in theoretical geochemistry make it possible to predict standard thermodynamic properties of proteins, nucleotides, lipids, and many metabolites including the constituents of the citric acid cycle, at all temperatures and pressures where life is known to occur, and beyond. Combining these predictions with constraints from geochemical data makes it possible to assess the relative stabilities of biomolecules. Resulting independent predictions of the environmental occurrence of homologous proteins and lipid side-chains can be compared with observations from metagenomic and metalipidomic data to quantify geochemical driving forces that shape the composition of biomolecules. In addition, the energetic costs of generating biomolecules from within a diverse range of habitable environments can be evaluated in terms of prevailing geochemical variables. Comparisons of geochemical bioenergetic calculations across habitats leads to the generalization that the availability of H2 determines the cost of autotrophic biosynthesis relative to the aquatic environment external to microbial cells, and that pH, temperature, pressure, and availability of C, N, P, and S are typically secondary. Increasingly reduced conditions, which are determined by reactions of water with mineral surfaces and mineral assemblages, allow many biosynthetic reactions to shift from costing energy to releasing energy. Protein and lipid synthesis, as well as the reverse citric acid cycle, become energy-releasing processes under these conditions. The resulting energy balances that determine habitability contrast dramatically with assumptions derived from oxic surface conditions, such as those where human biochemistry operates.

  4. Geochemical mapping of New Mexico, USA, using stream sediment data

    Science.gov (United States)

    Zumlot, Taisser; Goodell, Philip; Howari, Fares

    2009-10-01

    The spatial analysis of geochemical data has several environmental and geological applications. The present study investigated the regional distribution of Al, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, Pb, Sc, Th, Ti, U, V, and Zn elements in stream sediment samples from New Mexico State. These elements were studied in order to integrate them with geological and environmental characteristics of the area. Data are used from 27,798 samples that were originally collected during the national uranium resource evaluation (NURE) Hydrogeochemical and stream sediment reconnaissance (HSSR) program in the 1970s. The original data are available as U.S. Geological Survey Open-File Report 97-492. The study used a variety of data processing and filtering techniques that included univariate, bivariate, factor analyses and spatial analyses to transform the data into a useable format. Principal component analysis and GIS techniques are applied to classify the elements and to identify geochemical signatures, either natural or anthropogenic. The study found that the distribution of the investigated elements is mainly controlled by the bed rock chemistry. For example, along the Rio Grande rift and Jemez lineament a strong association between Co, Cr, Cu, Fe, Ni, Sc, Ti, V and Zn was observed and indicates that elements distribution in the area controlled by the mafic factor. The rare earth elements (REE) factor which is consists of Ce, La and U, also has strong, localized, clusters in the felsic centers in New Mexico.

  5. Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations.

    Science.gov (United States)

    Sengupta, Aditi; Wang, Yadi; Meira Neto, Antonio A; Matos, Katarena A; Dontsova, Katerina; Root, Rob; Neilson, Julie W; Maier, Raina M; Chorover, Jon; Troch, Peter A

    2016-09-11

    Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

  6. Sources and Residence Times of Groundwater in Shasta County, CA Determined by Isotopic Tracers

    Science.gov (United States)

    Peters, E.; Moran, J. E.; Deinhart, A.; Roberts, S. K.; Esser, B.; Visser, A.

    2015-12-01

    Large-volume springs are a significant source of water to communities in Shasta County. Aquifers in this region are developed in young volcanic formations and the age and flow of groundwater is not well characterized, making predicting the impact of drought and climate change on spring flow difficult. To better understand the water resources and the hydrogeology of the region and to better constrain the age of water produced by springs, we have sampled water from wells, springs, and streams for a suite of geochemical and isotopic tracers. We are using isotopic tracers because of the limited number of sampling points over a large area, leaving traditional hydrogeologic methods such as water levels and pump tests inadequate for a regional study. We analyzed samples for sulfur-35 (87.4 day half-life) and found detections in two springs, confirming the presence of a fraction of recently (1-2 years) recharged groundwater. Tritium (12.3 year half-life) activities show that some wells produce water recharged more than 5 decades ago, but most produce more recently recharged water. We will also report results for sodium-22 (2.6 year half-life), krypton-85 (10.8 year half-life), carbon-14 (5,730 year half-life), dissolved noble gases, stable isotopes of water, and helium isotopic composition. These isotopes are applied to determine the age (residence time) of groundwater over a broad age distribution, from less than one year to tens of thousands of years. These tracers should also provide information on aquifer volumes, help delineate groundwater flow, and help to identify recharge areas. A collection of groundwater ages from springs at high elevations to wells in the upper Sacramento Valley will help delineate groundwater flowpaths. Finally, groundwater residence times will help determine groundwater volume and recharge rates, and resolve questions related to drought vulnerability and effective adjustments in water resource management.

  7. Asian Tracer Experiment and Atmospheric Modeling (TEAM) Project: Draft Field Work Plan for the Asian Long-Range Tracer Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Allwine, K Jerry; Flaherty, Julia E.

    2007-08-01

    This report provides an experimental plan for a proposed Asian long-range tracer study as part of the international Tracer Experiment and Atmospheric Modeling (TEAM) Project. The TEAM partners are China, Japan, South Korea and the United States. Optimal times of year to conduct the study, meteorological measurements needed, proposed tracer release locations, proposed tracer sampling locations and the proposed durations of tracer releases and subsequent sampling are given. Also given are the activities necessary to prepare for the study and the schedule for completing the preparation activities leading to conducting the actual field operations. This report is intended to provide the TEAM members with the information necessary for planning and conducting the Asian long-range tracer study. The experimental plan is proposed, at this time, to describe the efforts necessary to conduct the Asian long-range tracer study, and the plan will undoubtedly be revised and refined as the planning goes forward over the next year.

  8. Geochemical and isotopic variations in shallow groundwater in areas of the Fayetteville Shale development, north-central Arkansas

    Science.gov (United States)

    Warner, Nathaniel R.; Kresse, Timothy M.; Hays, Phillip D.; Down, Adrian; Karr, Jonathan D.; Jackson, R.B.; Vengosh, Avner

    2013-01-01

    Exploration of unconventional natural gas reservoirs such as impermeable shale basins through the use of horizontal drilling and hydraulic fracturing has changed the energy landscape in the USA providing a vast new energy source. The accelerated production of natural gas has triggered a debate concerning the safety and possible environmental impacts of these operations. This study investigates one of the critical aspects of the environmental effects; the possible degradation of water quality in shallow aquifers overlying producing shale formations. The geochemistry of domestic groundwater wells was investigated in aquifers overlying the Fayetteville Shale in north-central Arkansas, where approximately 4000 wells have been drilled since 2004 to extract unconventional natural gas. Monitoring was performed on 127 drinking water wells and the geochemistry of major ions, trace metals, CH4 gas content and its C isotopes (δ13CCH4), and select isotope tracers (δ11B, 87Sr/86Sr, δ2H, δ18O, δ13CDIC) compared to the composition of flowback-water samples directly from Fayetteville Shale gas wells. Dissolved CH4 was detected in 63% of the drinking-water wells (32 of 51 samples), but only six wells exceeded concentrations of 0.5 mg CH4/L. The δ13CCH4 of dissolved CH4 ranged from −42.3‰ to −74.7‰, with the most negative values characteristic of a biogenic source also associated with the highest observed CH4 concentrations, with a possible minor contribution of trace amounts of thermogenic CH4. The majority of these values are distinct from the reported thermogenic composition of the Fayetteville Shale gas (δ13CCH4 = −35.4‰ to −41.9‰). Based on major element chemistry, four shallow groundwater types were identified: (1) low ( 100 mg/L and Ca–HCO3 dominated, (3) TDS > 100 mg/L and Na–HCO3dominated, and (4) slightly saline groundwater with TDS > 100 mg/L and Cl > 20 mg/L with elevated Br/Cl ratios (>0.001). The Sr (87Sr/86Sr = 0.7097

  9. Pollutant flows from a phosphogypsum disposal area to an estuarine environment: An insight from geochemical signatures.

    Science.gov (United States)

    Pérez-López, Rafael; Macías, Francisco; Cánovas, Carlos Ruiz; Sarmiento, Aguasanta Miguel; Pérez-Moreno, Silvia María

    2016-05-15

    Phosphogypsum wastes from phosphate fertilizer industries are stockpiled in stacks with high contamination potential. An assessment of the environmental impact, including the use of geochemical tracers such as rare earth elements (REE) and Cl/Br ratios, was carried out in the phosphogypsum stack located at the Estuary of Huelva (SW Spain). Inside the pile, highly polluted acid pore-waters flows up to the edge of the stack, emerging as small fluvial courses, known as edge outflows, which discharge directly into the estuary. The disposal area is divided into four zones; two unrestored zones with surface ponds of industrial process water and two a priori already-restored zones. However, an extensive sampling of edge outflows conducted in the perimeter of the four zones demonstrates the high potential of contamination of the whole stack, including those zones that were supposedly restored. These solutions are characterized by a pH of 1.9 and concentrations of 6100 mg/L for P, 1970 mg/L for S, 600 mg/L for F, 200mg/L for NH4(+), 100mg/L for Fe, 10-30 mg/L for Zn, As and U, and 1-10mg/L for Cr, Cu and Cd. Preliminary restoration actions and those planned for the future prioritize removal of ponded process water and cover of the phosphogypsum with artificial topsoil. These actions presuppose that the ponded process water percolates through the porous medium towards the edge up to reach the estuary. However, geochemical tracers rule out this connection and point to an estuarine origin for these leachates, suggesting a possible tidal-induced leaching of the waste pile in depth. These findings would explain the ineffectiveness of preliminary restoration measures and should be considered for the development of new action plans.

  10. Geochemical Characterization Using Geophysical Data and Markov Chain Monte Carlo Methods

    Science.gov (United States)

    Chen, J.; Hubbard, S.; Rubin, Y.; Murray, C.; Roden, E.; Majer, E.

    2002-12-01

    Although the spatial distribution of geochemical parameters is extremely important for many subsurface remediation approaches, traditional characterization of those parameters is invasive and laborious, and thus is rarely performed sufficiently to describe natural hydrogeological variability at the field-scale. This study is an effort to jointly use multiple sources of information, including noninvasive geophysical data, for geochemical characterization of the saturated and anaerobic portion of the DOE South Oyster Bacterial Transport Site in Virginia. Our data set includes hydrogeological and geochemical measurements from five boreholes and ground-penetrating radar (GPR) and seismic tomographic data along two profiles that traverse the boreholes. The primary geochemical parameters are the concentrations of extractable ferrous iron Fe(II) and ferric iron Fe(III). Since iron-reducing bacteria can reduce Fe(III) to Fe(II) under certain conditions, information about the spatial distributions of Fe(II) and Fe(III) may indicate both where microbial iron reduction has occurred and in which zone it is likely to occur in the future. In addition, as geochemical heterogeneity influences bacterial transport and activity, estimates of the geochemical parameters provide important input to numerical flow and contaminant transport models geared toward bioremediation. Motivated by our previous research, which demonstrated that crosshole geophysical data could be very useful for estimating hydrogeological parameters, we hypothesize in this study that geochemical and geophysical parameters may be linked through their mutual dependence on hydrogeological parameters such as lithofacies. We attempt to estimate geochemical parameters using both hydrogeological and geophysical measurements in a Bayesian framework. Within the two-dimensional study domain (12m x 6m vertical cross section divided into 0.25m x 0.25m pixels), geochemical and hydrogeological parameters were considered as data

  11. Geochemical study for volcanic surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Panichi, C.; La Ruffa, G. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research Ghezzano, PI (Italy)

    2000-07-01

    For years, geologists have been striving to reconstruct volcanic eruptions from the analysis of pyroclastic deposits and lava flows on the surface of the earth and in the oceans. This effort has produced valuable information on volcanic petrology and magma generation, separation, mixing, crystallisation, and interaction with water in phreatomagmatic and submarine eruptions. The volcanological process are tied to the dynamics of the earth's crust and lithosphere. The mantle, subducted oceanic crust, and continental crust contain different rock types and are sources of different magmas. Magmas consist primarily of completely or partially molten silicates containing volatile materials either dissolved in the melt or as bubbles of gas. The silicate and volatile portions affect the physical properties of magma and, therefore, the nature of a volcanic eruption.

  12. Geochemical engineering problem identification and program description. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Crane, C.H.; Kenkeremath, D.C.

    1981-05-01

    The Geochemical Engineering Program has as its goal the improvement of geochemical fluid management techniques. This document presents the strategy and status of the Geochemical Engineering Program. The magnitude and scope of geochemical-related problems constraining geothermal industry productivity are described. The goals and objectives of the DGE Geochemical Engineering Program are defined. The rationale and strategy of the program are described. The structure, priorities, funding, and management of specific elements within the program are delineated, and the status of the overall program is presented.

  13. A geochemical examination of humidity cell tests

    Science.gov (United States)

    Maest, Ann; Nordstrom, D. Kirk

    2017-01-01

    Humidity cell tests (HCTs) are long-term (20 to >300 weeks) leach tests that are considered by some to be the among the most reliable geochemical characterization methods for estimating the leachate quality of mined materials. A number of modifications have been added to the original HCT method, but the interpretation of test results varies widely. We suggest that the HCTs represent an underutilized source of geochemical data, with a year-long test generating approximately 2500 individual chemical data points. The HCT concentration peaks and valleys can be thought of as a “chromatogram” of reactions that may occur in the field, whereby peaks in concentrations are associated with different geochemical processes, including sulfate salt dissolution, sulfide oxidation, and dissolution of rock-forming minerals, some of which can neutralize acid. Some of these reactions occur simultaneously, some do not, and geochemical modeling can be used to help distinguish the dominant processes. Our detailed examination, including speciation and inverse modeling, of HCTs from three projects with different geology and mineralization shows that rapid sulfide oxidation dominates over a limited period of time that starts between 40 and 200 weeks of testing. The applicability of laboratory tests results to predicting field leachate concentrations, loads, or rates of reaction has not been adequately demonstrated, although early flush releases and rapid sulfide oxidation rates in HCTs should have some relevance to field conditions. Knowledge of possible maximum solute concentrations is needed to design effective treatment and mitigation approaches. Early flush and maximum sulfide oxidation results from HCTs should be retained and used in environmental models. Factors that complicate the use of HCTs include: sample representation, time for microbial oxidizers to grow, sample storage before testing, geochemical reactions that add or remove constituents, and the HCT results chosen for use

  14. Rare Earth elements as sediment tracers in Mangrove ecosystems

    Science.gov (United States)

    Ramanathan, A. L.; Swathi, S.

    2013-05-01

    Rare earth elements have been widely used as geochemical source fingerprints of rocks and sediments to study processes involving cosmo-chemistry, igneous petrology, tectonic setting and for investigations of water-rock interactions and weathering processes including transport of weathering products to the oceans.Many studies have addressed the use of REEs in investigating the environmental impact of human activity and demonstrated that the REE natural distribution in sediment from densely industrialised and populated regions can be altered by anthropogenic influences.The coastal wetlands like Mangroves are ultimate sinks for all the material derived from the terrestrial and marine environment.The high productivity and low ratio of sediment respiration to net primary production gives mangrove sediments the potential for long-term sequestration of these pollutants/metals before reaching the coastal ocean. Geochemical study of REE in these sedimentary systems is useful for determining the nature of the biogeochemical processes. In particular, REE show a great sensitivity to pH changes, redox conditions and adsorption/ desorption reactions. So, they may be used as markers of discharge provenance, weathering processes, changes in environmental conditions in the water and sediments of Mangrove/wetland systems. Our study aims to establish the abundance, distribution and enrichment of REEs to track the sediment sources and biogeochemical processes occurring in the mangrove environment.Core sediments were collected from the different environmental settings within the Pichavaram mangrove area.Higher REE concentration in Pichavaram sediments indicated greater input from sources like terrestrial weathering and anthropogenic activities which in turn are affected by saline mixing and dynamic physico-chemical processes occurring in the mangrove environment. REE enrichment order was attributed to the alkaline pH (7-8.5) and reducing conditions prevailing in the mangrove

  15. CityFlux perfluorocarbon tracer experiments

    Science.gov (United States)

    Petersson, F. K.; Martin, D.; White, I. R.; Henshaw, S. J.; Nickless, G.; Longley, I.; Percival, C. J.; Gallagher, M.; Shallcross, D. E.

    2010-07-01

    In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  16. CityFlux perfluorocarbon tracer experiments

    Directory of Open Access Journals (Sweden)

    F. K. Petersson

    2010-01-01

    Full Text Available In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m.

    The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site.

    Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail.

    The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this.

    The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  17. CityFlux perfluorocarbon tracer experiments

    Directory of Open Access Journals (Sweden)

    F. K. Petersson

    2010-07-01

    Full Text Available In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m.

    The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site.

    Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail.

    The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this.

    The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

  18. Geochemical evidence for the melting of subducting oceanic lithosphere at plate edges.

    Science.gov (United States)

    Yogodzinski, G M; Lees, J M; Churikova, T G; Dorendorf, F; Wöerner, G; Volynets, O N

    2001-01-25

    Most island-arc magmatism appears to result from the lowering of the melting point of peridotite within the wedge of mantle above subducting slabs owing to the introduction of fluids from the dehydration of subducting oceanic crust. Volcanic rocks interpreted to contain a component of melt (not just a fluid) from the subducting slab itself are uncommon, but possible examples have been recognized in the Aleutian islands, Baja California, Patagonia and elsewhere. The geochemically distinctive rocks from these areas, termed 'adakites, are often associated with subducting plates that are young and warm, and therefore thought to be more prone to melting. But the subducting lithosphere in some adakite locations (such as the Aleutian islands) appears to be too old and hence too cold to melt. This implies either that our interpretation of adakite geochemistry is incorrect, or that our understanding of the tectonic context of adakites is incomplete. Here we present geochemical data from the Kamchatka peninsula and the Aleutian islands that reaffirms the slab-melt interpretation of adakites, but in the tectonic context of the exposure to mantle flow around the edge of a torn subducting plate. We conclude that adakites are likely to form whenever the edge of a subducting plate is warmed or ablated by mantle flow. The use of adakites as tracers for such plate geometry may improve our understanding of magma genesis and thermal structure in a variety of subduction-zone environments.

  19. Detection of tracer materials in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, A.; Lovelock, J.E.

    1981-12-08

    As oxygen is an electron absorber it is desirable, when monitoring an atmospheric flow for the presence of tracer materials capable of detection in an electron capture detector, to remove the oxygen from the flow to the detector. The invention introduces a hydrogen supply directly into the atmospheric flow to allow the hydrogen to combine catalytically with the oxygen content of the flow to form water or water vapor. The thus formed water or water vapor is extracted from the flow proceeding to the detector. The reaction can occur within a palladium or palladium alloy conduit forming a part of the flow path to the detector.

  20. Open Path Tracer Measurements of Methane Emissions from Free Ranging Cattle

    Science.gov (United States)

    Griffith, D. W.; Tonini, M.; Bryant, G. R.; Eckard, R.; Grainger, C.; McGinn, S. M.

    2006-12-01

    This paper addresses the need for more accurate and representative measurements of methane emissions from cattle in their natural environments. Improved measurements are or will be required to quantify methane emissions for national greenhouse gas budgets and future carbon trading schemes, and to assess the effectiveness of proposed mitigation strategies. We describe measurements of methane emissions from free- ranging cattle grazing in their natural outdoor environments in Australia and New Zealand. We employ a novel tracer method in which nitrous oxide is released at a known rate from fenceline tubing or canisters attached to individual cows, and the mixing ratios of methane, nitrous oxide and carbon dioxide are measured continuously and simultaneously downwind by open path FTIR spectroscopy. Correlations between methane, nitrous oxide and carbon dioxide can be used to infer the herd-average methane flux directly. Measurements will be compared with the more conventional SF6 ruminal tracer technique.

  1. Geochemical surveys in the United States in relation to health.

    Science.gov (United States)

    Tourtelot, H.A.

    1979-01-01

    Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes. -Author

  2. Tracer Dispersion in a Multi-compartment Structure

    CERN Document Server

    Skvortsov, A; Gamble, G; Roberts, M; Ilaya, O; Pitaliadda, D

    2012-01-01

    An experimental study of the tracer dispersion in a complex structure is presented. A point source of tracer (dyed salt) was placed inside a multi-compartment structure embedded in water tank. This experimental setting corresponds to a hazardous tracer release inside the engineering structure (building, ship, aircarft etc). A system of conductivity sensors was deployed to monitor the propagation of a tracer plume in the structure, including tracer trapping inside some compartments and its release to the outside environment through the external openings. The experimental data is processed by employing the ideas of scaling and self-similarity of underlying transport processes. The established and validated scaling laws provide a rigorous way to up-scale the results of laboratory modeling to real operational scenarios and can be used as an important step in the development of risk-assessment models for the first responders to hazardous releases. Keywords: hazardous plume, tracer dispersion, diffusion and advecti...

  3. Quantifying Methane Fluxes Simply and Accurately: The Tracer Dilution Method

    Science.gov (United States)

    Rella, Christopher; Crosson, Eric; Green, Roger; Hater, Gary; Dayton, Dave; Lafleur, Rick; Merrill, Ray; Tan, Sze; Thoma, Eben

    2010-05-01

    Methane is an important atmospheric constituent with a wide variety of sources, both natural and anthropogenic, including wetlands and other water bodies, permafrost, farms, landfills, and areas with significant petrochemical exploration, drilling, transport, or processing, or refining occurs. Despite its importance to the carbon cycle, its significant impact as a greenhouse gas, and its ubiquity in modern life as a source of energy, its sources and sinks in marine and terrestrial ecosystems are only poorly understood. This is largely because high quality, quantitative measurements of methane fluxes in these different environments have not been available, due both to the lack of robust field-deployable instrumentation as well as to the fact that most significant sources of methane extend over large areas (from 10's to 1,000,000's of square meters) and are heterogeneous emitters - i.e., the methane is not emitted evenly over the area in question. Quantifying the total methane emissions from such sources becomes a tremendous challenge, compounded by the fact that atmospheric transport from emission point to detection point can be highly variable. In this presentation we describe a robust, accurate, and easy-to-deploy technique called the tracer dilution method, in which a known gas (such as acetylene, nitrous oxide, or sulfur hexafluoride) is released in the same vicinity of the methane emissions. Measurements of methane and the tracer gas are then made downwind of the release point, in the so-called far-field, where the area of methane emissions cannot be distinguished from a point source (i.e., the two gas plumes are well-mixed). In this regime, the methane emissions are given by the ratio of the two measured concentrations, multiplied by the known tracer emission rate. The challenges associated with atmospheric variability and heterogeneous methane emissions are handled automatically by the transport and dispersion of the tracer. We present detailed methane flux

  4. Geochemical dynamics in selected Yellowstone hydrothermal features

    Science.gov (United States)

    Druschel, G.; Kamyshny, A.; Findlay, A.; Nuzzio, D.

    2010-12-01

    Yellowstone National Park has a wide diversity of thermal features, and includes springs with a range of pH conditions that significantly impact sulfur speciation. We have utilized a combination of voltammetric and spectroscopic techniques to characterize the intermediate sulfur chemistry of Cinder Pool, Evening Primrose, Ojo Caliente, Frying Pan, Azure, and Dragon thermal springs. These measurements additionally have demonstrated the geochemical dynamics inherent in these systems; significant variability in chemical speciation occur in many of these thermal features due to changes in gas supply rates, fluid discharge rates, and thermal differences that occur on second time scales. The dynamics of the geochemical settings shown may significantly impact how microorganisms interact with the sulfur forms in these systems.

  5. Seeking a geochemical identifier for authigenic carbonate.

    Science.gov (United States)

    Zhao, Ming-Yu; Zheng, Yong-Fei; Zhao, Yan-Yan

    2016-03-07

    Authigenic carbonate was recently invoked as a third major global carbon sink in addition to primary marine carbonate and organic carbon. Distinguishing the two carbonate sinks is fundamental to our understanding of Earth's carbon cycle and its role in regulating the evolution of atmospheric oxygen. Here, using microscale geochemical measurements of carbonates in Early Triassic strata, we show that the growth of authigenic carbonate follows a different trajectory from primary marine carbonate in a cross-plot of uranium concentration and carbon isotope composition. Thus, a combination of the two geochemical variables is able to distinguish between the two carbonate sinks. The temporal distribution of authigenic carbonates in the Early Triassic strata suggests that the increase in the extent of carbonate authigenesis acted as a negative feedback to the elevated atmospheric CO2 concentration.

  6. Optimal initial condition of passive tracers for their maximal mixing in finite time

    Science.gov (United States)

    Farazmand, Mohammad

    2017-05-01

    The efficiency of fluid flow for mixing passive tracers is often limited by fundamental laws and/or design constraints, such that a perfectly homogeneous mixture cannot be obtained in finite time. Here we address the natural corollary question: Given a fluid flow, what is the optimal initial tracer pattern that leads to the most homogeneous mixture after a prescribed finite time? For ideal passive tracers, we show that this optimal initial condition coincides with the right singular vector (corresponding to the smallest singular value) of a suitably truncated Perron-Frobenius (PF) operator. The truncation of the PF operator is made under the assumption that there is a small length-scale threshold ℓν under which the tracer blobs are considered, for all practical purposes, completely mixed. We demonstrate our results on two examples: a prototypical model known as the sine flow and a direct numerical simulation of two-dimensional turbulence. Evaluating the optimal initial condition through this framework requires only the position of a dense grid of fluid particles at the final instance and their preimages at the initial instance of the prescribed time interval. As such, our framework can be readily applied to flows where such data are available through numerical simulations or experimental measurements.

  7. Fate of injected CO2 in the Wilcox Group, Louisiana, Gulf Coast Basin: Chemical and isotopic tracers of microbial-brine-rock-CO2 interactions

    Science.gov (United States)

    Shelton, Jenna L.; McIntosh, Jennifer C.; Warwick, Peter D.; Lee Zhi Yi, Amelia

    2016-01-01

    The “2800’ sandstone” of the Olla oil field is an oil and gas-producing reservoir in a coal-bearing interval of the Paleocene–Eocene Wilcox Group in north-central Louisiana, USA. In the 1980s, this producing unit was flooded with CO2 in an enhanced oil recovery (EOR) project, leaving ∼30% of the injected CO2 in the 2800’ sandstone post-injection. This study utilizes isotopic and geochemical tracers from co-produced natural gas, oil and brine to determine the fate of the injected CO2, including the possibility of enhanced microbial conversion of CO2 to CH4 via methanogenesis. Stable carbon isotopes of CO2, CH4 and DIC, together with mol% CO2 show that 4 out of 17 wells sampled in the 2800’ sandstone are still producing injected CO2. The dominant fate of the injected CO2appears to be dissolution in formation fluids and gas-phase trapping. There is some isotopic and geochemical evidence for enhanced microbial methanogenesis in 2 samples; however, the CO2 spread unevenly throughout the reservoir, and thus cannot explain the elevated indicators for methanogenesis observed across the entire field. Vertical migration out of the target 2800’ sandstone reservoir is also apparent in 3 samples located stratigraphically above the target sand. Reservoirs comparable to the 2800’ sandstone, located along a 90-km transect, were also sampled to investigate regional trends in gas composition, brine chemistry and microbial activity. Microbial methane, likely sourced from biodegradation of organic substrates within the formation, was found in all oil fields sampled, while indicators of methanogenesis (e.g. high alkalinity, δ13C-CO2 and δ13C-DIC values) and oxidation of propane were greatest in the Olla Field, likely due to its more ideal environmental conditions (i.e. suitable range of pH, temperature, salinity, sulfate and iron concentrations).

  8. Sr and U isotope ratios in soil waters as tracers of weathering dynamic in soils (Strengbach catchment - Vosges-mountains; France).

    Science.gov (United States)

    Chabaux, François; Prunier, Jonathan; Pierret, Marie-Claire; Stille, Peter

    2013-04-01

    It is proposed in this study to highlight the interest of multi-tracer geochemical approaches combining measurement of major and trace element concentrations along with U and Sr isotopic ratios to constrain the characterization of the present-day weathering processes controlling the chemical composition of waters and soils in natural ecosystems. This is important if we want to predict and to model correctly the response of ecosystems to recent environmental changes. The approach is applied to the small granitic Strengbah Catchment, located in the Vosges Mountain (France), used and equipped as a hydro-geochemical observatory since 1986 (Observatoire Hydro-Géochimique de l'Environnement; http://ohge.u-strasbg.fr). This study includes the analysis of major and trace element concentrations and (U-Sr) isotope ratios in soil solutions collected within two soil profiles located on two experimental plots of this watershed, along with the analysis of soil samples and vegetation samples from these two plots. The depth variation of elemental concentrations of soil solutions confirms the important influence of the vegetation cycling on the budget of Ca, K, Rb and Sr, whereas Mg and Si budget in soil solutions are quasi exclusively controlled by weathering processes. Variation of Sr, and U isotopic ratios with depth also demonstrates that the sources and biogeochemical processes controlling the Sr budget of soil solutions is different in the uppermost soil horizons and in the deeper ones, and clearly influence by the vegetation cycling. From the obtained data, it can be therefore proposed a scheme where in addition to the external flux associated to the decomposition of organic matter and throughfall, occurs a double lithogenic flux: a surface flux which can be associated to dissolution of secondary minerals contained in fine silt fractions and a deeper one, controlled by water-rock interactions which can mobilize elements from primary minerals like plagioclases or orthose

  9. Geochemical Investigations of Respirable Particulate Matter

    OpenAIRE

    Jurinski, Joseph Bernard Jr.

    1998-01-01

    GEOCHEMICAL INVESTIGATIONS OF RESPIRABLE PARTICULATE MATTER Joseph Bernard Jurinski (Abstract) Over the course of our lives we are exposed to airborne particulate matter in the workplace, home, and environment that results in the deposition of millions of particles in the lung. These exposures may result in disease if they are significant enough. The potential for harmful exposure depends in part on the dust's biodurability and the bioavailability of harmful constituents d...

  10. Geochemical data requirements for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Savage, D.; Stenhouse, M.J.

    1997-08-15

    This report reviews the geochemical data requirements and their application to the assessment of the performance of a geologic repository for radioactive wastes. It is concluded that information must be acquired on pH, redox reactions, inorganic and organic ligands in groundwater and colloids and processes such as precipitation, adsorption and diffusion and palaeohydrogeologic information in order to predict present hydrogeologic properties of potential repository sites. (UK).

  11. Arsenic and other oxyanion-forming trace elements in an alluvial basin aquifer: Evaluating sources and mobilization by isotopic tracers (Sr, B, S, O, H, Ra)

    Energy Technology Data Exchange (ETDEWEB)

    Vinson, David S., E-mail: dsv3@duke.edu [Duke University, Division of Earth and Ocean Sciences, Box 90227, Durham, NC 27708 (United States); McIntosh, Jennifer C. [University of Arizona, Department of Hydrology and Water Resources, 1133 E. James E. Rogers Way, Tucson, AZ 85721 (United States); Dwyer, Gary S.; Vengosh, Avner [Duke University, Division of Earth and Ocean Sciences, Box 90227, Durham, NC 27708 (United States)

    2011-08-15

    oxyanion-forming trace element concentrations (B, V, Cr, Se, Mo, Sb), and F{sup -} concentrations are associated with a group of waters exhibiting lower {sup 87}Sr/{sup 86}Sr ratios (0.71012-0.71503), suggesting that sediments derived from Tertiary felsic volcanic rocks are a significant source of these trace elements in groundwater. {delta}{sup 34}S{sub SO4} (2.0-13.4 per mille) and {delta}{sup 11}B (-6.7 per mille to 18.2 per mille) variations suggest that rain-derived B and SO{sub 4}{sup 2-} plus marine gypsum derived from Paleozoic sedimentary rocks and B derived from felsic volcanic rocks explain the observed values. In addition to the sources of these elemental and isotopic signatures, down-gradient hydrogeochemical modification associated with silicate weathering and perhaps cation exchange are recorded by the decreasing Ca/Na ratio. Very low levels of {sup 226}Ra in groundwater relative to U throughout the basin-fill aquifer are consistent with the oxic, neutral to high-pH conditions in which mobility of U is strongly favored relative to Ra. Used in combination, multiple isotopic and geochemical tracers can provide valuable information for understanding the relative importance of sediment source and hydrogeochemical processes for observed levels of As and other naturally-occurring trace elements. These tracers, in particular {sup 87}Sr/{sup 86}Sr with its sensitivity to aquifer sediment source, can be applied to other alluvial basin-fill aquifers in the southwestern USA where multiple sediment types contribute varying amounts of As and other oxyanion-forming trace elements to groundwater.

  12. Compilation and analyses of results from cross-hole tracer tests with conservative tracers

    Energy Technology Data Exchange (ETDEWEB)

    Hjerne, Calle; Nordqvist, Rune; Harrstroem, Johan (Geosigma AB (Sweden))

    2010-09-15

    Radionuclide transport in hydrogeological formations is one of the key factors for the safety analysis of a future repository of nuclear waste. Tracer tests have therefore been an important field method within the SKB investigation programmes at several sites since the late 1970's. This report presents a compilation and analyses of results from cross-hole tracer tests with conservative tracers performed within various SKB investigations. The objectives of the study are to facilitate, improve and reduce uncertainties in predictive tracer modelling and to provide supporting information for SKB's safety assessment of a final repository of nuclear waste. More specifically, the focus of the report is the relationship between the tracer mean residence time and fracture hydraulic parameters, i.e. the relationship between mass balance aperture and fracture transmissivity, hydraulic diffusivity and apparent storativity. For 74 different combinations of pumping and injection section at six different test sites (Studsvik, Stripa, Finnsjoen, Aespoe, Forsmark, Laxemar), estimates of mass balance aperture from cross-hole tracer tests as well as transmissivity were extracted from reports or in the SKB database Sicada. For 28 of these combinations of pumping and injection section, estimates of hydraulic diffusivity and apparent storativity from hydraulic interference tests were also found. An empirical relationship between mass balance aperture and transmissivity was estimated, although some uncertainties for individual data exist. The empirical relationship between mass balance aperture and transmissivity presented in this study deviates considerably from other previously suggested relationships, such as the cubic law and transport aperture as suggested by /Dershowitz and Klise 2002/, /Dershowitz et al. 2002/ and /Dershowitz et al. 2003/, which also is discussed in this report. No clear and direct empirical relationship between mass balance aperture and hydraulic

  13. Monitoring active volcanoes: The geochemical approach

    Directory of Open Access Journals (Sweden)

    Takeshi Ohba

    2011-06-01

    Full Text Available

    The geochemical surveillance of an active volcano aims to recognize possible signals that are related to changes in volcanic activity. Indeed, as a consequence of the magma rising inside the volcanic "plumbing system" and/or the refilling with new batches of magma, the dissolved volatiles in the magma are progressively released as a function of their relative solubilities. When approaching the surface, these fluids that are discharged during magma degassing can interact with shallow aquifers and/or can be released along the main volcano-tectonic structures. Under these conditions, the following main degassing processes represent strategic sites to be monitored.

    The main purpose of this special volume is to collect papers that cover a wide range of topics in volcanic fluid geochemistry, which include geochemical characterization and geochemical monitoring of active volcanoes using different techniques and at different sites. Moreover, part of this volume has been dedicated to the new geochemistry tools.

  14. Geochemical engineering and materials program plan

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-08-01

    The Department of Energy (DOE) was designated as lead agency in discharging the overall legislative mandate for federal R&D to assist the private sector in developing appropriate technology for exploiting geothermal energy resources. The Geochemical Engineering and Materials (GEM) Program was conceived, as part of DOE'S overall strategy, to address specific and plant-wide problems and uncertainties in the use of materials and in geochemical engineering. This program assists industry in the conduct of long-term,high-risk R&D needed to overcome the significant technical and economic GEM-related obstacles faced by developers and potential developers of this alternative energy source. The program focuses on: (1) Increasing the knowledge about the properties of materials and their performance under geothermal energy system conditions; (2) Developing and utilizing more reliable and/or cost-effective materials than previously available; and (3) Developing a greater understanding of and control over geochemical processes during fluid production and transport, energy conversion, and waste management. As a stand-alone program and as support to other DOE geothermal technology development programs, the GEM Program contributes to the feasibility of designing and operating efficient, reliable, and safe fluid handling and energy conversion systems.

  15. The geochemistry of naturally occurring methane and saline groundwater in an area of unconventional shale gas development

    Science.gov (United States)

    Harkness, Jennifer S.; Darrah, Thomas H.; Warner, Nathaniel R.; Whyte, Colin J.; Moore, Myles T.; Millot, Romain; Kloppmann, Wolfram; Jackson, Robert B.; Vengosh, Avner

    2017-07-01

    Since naturally occurring methane and saline groundwater are nearly ubiquitous in many sedimentary basins, delineating the effects of anthropogenic contamination sources is a major challenge for evaluating the impact of unconventional shale gas development on water quality. This study investigates the geochemical variations of groundwater and surface water before, during, and after hydraulic fracturing and in relation to various geospatial parameters in an area of shale gas development in northwestern West Virginia, United States. To our knowledge, we are the first to report a broadly integrated study of various geochemical techniques designed to distinguish natural from anthropogenic sources of natural gas and salt contaminants both before and after drilling. These measurements include inorganic geochemistry (major cations and anions), stable isotopes of select inorganic constituents including strontium (87Sr/86Sr), boron (δ11B), lithium (δ7Li), and carbon (δ13C-DIC), select hydrocarbon molecular (methane, ethane, propane, butane, and pentane) and isotopic tracers (δ13C-CH4, δ13C-C2H6), tritium (3H), and noble gas elemental and isotopic composition (helium, neon, argon) in 105 drinking-water wells, with repeat testing in 33 of the wells (total samples = 145). In a subset of wells (n = 20), we investigated the variations in water quality before and after the installation of nearby ( 50 mg/L). The integrated geochemical data indicate that the saline groundwater originated via naturally occurring processes, presumably from the migration of deeper methane-rich brines that have interacted extensively with coal lithologies. These observations were consistent with the lack of changes in water quality observed in drinking-water wells following the installation of nearby shale-gas wells. In contrast to groundwater samples that showed no evidence of anthropogenic contamination, the chemistry and isotope ratios of surface waters (n = 8) near known spills or leaks

  16. Cross-hole tracer experiment reveals rapid fluid flow and low effective porosity in the upper oceanic crust

    Science.gov (United States)

    Neira, N. M.; Clark, J. F.; Fisher, A. T.; Wheat, C. G.; Haymon, R. M.; Becker, K.

    2016-09-01

    Numerous field, laboratory, and modeling studies have explored the flows of fluid, heat, and solutes during seafloor hydrothermal circulation, but it has been challenging to determine transport rates and flow directions within natural systems. Here we present results from the first cross-hole tracer experiment in the upper oceanic crust, using four subseafloor borehole observatories equipped with autonomous samplers to track the transport of a dissolved tracer (sulfur hexafluoride, SF6) injected into a ridge-flank hydrothermal system. During the first three years after tracer injection, SF6 was transported both north and south through the basaltic aquifer. The observed tracer transport rate of ∼2-3 m/day is orders of magnitude greater than bulk rates of flow inferred from thermal and chemical observations and calculated with coupled fluid-heat flow simulations. Taken together, these results suggest that the effective porosity of the upper volcanic crust through which much tracer was transported is <1%, with fluid flowing rapidly along a few well-connected channels. This is consistent with the heterogeneous (layered, faulted, and/or fractured) nature of the volcanic upper oceanic crust.

  17. Performance Testing of Tracer Gas and Tracer Aerosol Detectors for use in Radionuclide NESHAP Compliance Testing

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lattin, Rebecca Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-28

    The Rad-NESHAP program, part of the Air Quality Compliance team of LANL’s Compliance Programs group (EPC-CP), and the Radiation Instrumentation & Calibration team, part of the Radiation Protection Services group (RP-SVS), frequently partner on issues relating to characterizing air flow streams. This memo documents the most recent example of this partnership, involving performance testing of sulfur hexafluoride detectors for use in stack gas mixing tests. Additionally, members of the Rad-NESHAP program performed a functional trending test on a pair of optical particle counters, comparing results from a non-calibrated instrument to a calibrated instrument. Prior to commissioning a new stack sampling system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniformity of tracer gas and aerosol mixing in the air stream. For these mix tests, tracer media (sulfur hexafluoride gas or liquid oil aerosol particles) are injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of these media concentrations must be under 20% when evaluated over the central 2/3 area of the stack or duct. The instruments which measure these air concentrations must be tested prior to the stack tests in order to ensure their linear response to varying air concentrations of either tracer gas or tracer aerosol. The instruments used in tracer gas and aerosol mix testing cannot be calibrated by the LANL Standards and Calibration Laboratory, so they would normally be sent off-site for factory calibration by the vendor. Operational requirements can prevent formal factory calibration of some instruments after they have been used in hazardous settings, e.g., within a radiological facility with potential airborne contamination. The performance tests described in this document are intended to demonstrate the reliable

  18. How to chase a tracer - combining conventional salt tracer testing and direct push electrical conductivity profiling for enhanced aquifer characterization

    Science.gov (United States)

    Vienken, Thomas; Huber, Emanuel; Kreck, Manuel; Huggenberger, Peter; Dietrich, Peter

    2017-01-01

    Tracer testing is a well-established technique in hydrogeological site characterization. However, certain a priori knowledge of the hydraulic regime is required beforehand to avoid test failure, e.g. miss of tracer. In this study, we propose a novel tracer test concept for the hydraulic characterization of shallow unconsolidated sedimentary deposits when only scarce a priori information on the hydraulic regime is available. Therefore, we combine conventional salt tracer testing with direct push vertical high resolution electrical conductivity logging. The proposed tracer test concept was successfully tested on coarse, braided river deposits of the Tagliamento River, Italy. With limited a priori information available two tracer tests were performed in three days to reliably determine ground water flow direction and velocity allowing on-site decision-making to adaptively install observation wells for reliable breakthrough curve measurements. Furthermore, direct push vertical electrical profiling provided essential information about the plume characteristics with outstanding measurement resolution and efficiency.

  19. A three-component hydrograph separation based on geochemical tracers in a tropical mountainous headwater catchment in northern Thailand

    NARCIS (Netherlands)

    Hugenschmidt, C.; Ingwersen, J.; Sangchan, W.; Sukvanachaikul, Y.; Duffner, A.; Uhlenbrook, S.; Streck, T.

    2014-01-01

    Land-use change in the mountainous parts of northern Thailand is reflected by an increased application of agrochemicals, which may be lost to surface and groundwater. The close relation between flow paths and contaminant transport within hydrological systems requires recognizing and understanding th

  20. Geochemical Tracers of Processes Affecting the Formation of Seafloor Hydrothermal Fluids and Deposits in the Manus Back-Arc Basin

    Science.gov (United States)

    2009-02-01

    alteration process in hypogene environments by magmatic gas contamination of meteoric fluids. Economic Geology 78, 73–90. Chiba H., Uchiyama N., and Teagle...sulfur from active crater lakes. Journal of Volcanology and Geothermal Research 97(1–4), 287. Lackschewitz K. S., Devey C. W., Stoffers P., Botz R...reaction of sulfur dioxide in hydrothermal fluids: Implications for the δ34S variations of dissolved bisulfate and elemental sulfur from active crater

  1. 7Be:A Geochemical Tracer for Seasonal Erosion of Surface Soil in Watershed of Lake Hongfeng,Guizahou ,China

    Institute of Scientific and Technical Information of China (English)

    BAIZHANGUO; P.H.SANTSCHI; 等

    1996-01-01

    7Be penetrative depth in undisturbed surface soil is within 4mm.7Be activity shows exponential decrease with soil depth,which is expressed as a diffusion process.7Be penetrative depth in undisturbed surface soil is apparently deeper in the fall (0.22-0.37g cm-1) than in the spring (0.11-0.28g cm-2) at the same site;Whereas,7Be apparent activity at the top of surface soil is higher in the spring (0.3-2.2Bq g-1)than in the fall (0.2-0.5Bqg-1) at the same site,The 7Be inventory(189-544Bq m-2)changes with both locations and seasons.Although the 7Be flux to the earth's surface increases with amount of precipitation,its maximum inventory in the soil profiles decreases to 30%-40% after the rainy period.Calculated by the diffusion equation,the erosion and accumulation rates of soil particles are agreeable with the observation in situ,Which shows that the rates in fall are 1.5 times those in spring.The eroded soil particles almost all have been removed on the tablelands rathel than transported into the drainage system.This indicates that the soil erosion process in the karst region is only partial transportation within a short distance.

  2. Transport and attenuation of carboxylate-modified latex microspheres in fractured rock laboratory and field tracer tests

    Science.gov (United States)

    Becker, M.W.; Reimus, P.W.; Vilks, P.

    1999-01-01

    Understanding colloid transport in ground water is essential to assessing the migration of colloid-size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks of pathogen contamination in drinking water wells. Much has been learned through laboratory and field-scale colloid tracer tests, but progress has been hampered by a lack of consistent tracer testing methodology at different scales and fluid velocities. This paper presents laboratory and field tracer tests in fractured rock that use the same type of colloid tracer over an almost three orders-of-magnitude range in scale and fluid velocity. Fluorescently-dyed carboxylate-modified latex (CML) microspheres (0.19 to 0.98 ??m diameter) were used as tracers in (1) a naturally fractured tuff sample, (2) a large block of naturally fractured granite, (3) a fractured granite field site, and (4) another fractured granite/schist field site. In all cases, the mean transport time of the microspheres was shorter than the solutes, regardless of detection limit. In all but the smallest scale test, only a fraction of the injected microsphere mass was recovered, with the smaller microspheres being recovered to a greater extent than the larger microspheres. Using existing theory, we hypothesize that the observed microsphere early arrival was due to volume exclusion and attenuation was due to aggregation and/or settling during transport. In most tests, microspheres were detected using flow cytometry, which proved to be an excellent method of analysis. CML microspheres appear to be useful tracers for fractured rock in forced gradient and short-term natural gradient tests, but longer residence times may result in small microsphere recoveries.Understanding colloid transport in ground water is essential to assessing the migration of colloid-size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks

  3. Geochemical Study of Natural CO2 Emissions in the French Massif Central: How to Predict Origin, Processes and Evolution of CO2 Leakage Étude géochimique des émissions naturelles de CO2 du Massif Central : origine et processus de migration du gaz

    Directory of Open Access Journals (Sweden)

    Battani A.

    2010-05-01

    Full Text Available This study presents an overview of some results obtained within the French ANR (National Agency of Research supported Géocarbone-Monitoring research program. The measurements were performed in Sainte-Marguerite, located in the French Massif Central. This site represents a natural laboratory for CO2/fluid/rock interactions studies, as well as CO2 migration mechanisms towards the surface. The CO2 leaking character of the studied area also allows to test and validate measurements methods and verifications for the future CO2 geological storage sites. During these surveys, we analyzed soil CO2 fluxes and concentrations. We sampled and analyzed soil gases, and gas from carbo-gaseous bubbling springs. A one-month continuous monitoring was also tested, to record the concentration of CO2 both in atmosphere and in the soil at a single point. We also developed a new methodology to collect soil gas samples for noble gas abundances and isotopic analyses, as well as carbon isotopic ratios. Our geochemical results, combined with structural geology, show that the leaking CO2 has a very deep origin, partially mantle derived. The gas rises rapidly along normal and strike-slip active faults. CO2 soil concentrations (also showing a mantle derived component and CO2 fluxes are spatially variable, and reach high values. The recorded atmospheric CO2 is not very high, despite the important CO2 degassing throughout the whole area. Cette étude présente les principaux résultats de campagnes de monitoring géochimique menées en 2006 et 2007 dans le cadre du projet Géocarbone-Monitoring, sur le site de Sainte-Marguerite, situé dans le Massif Central. Ce site constitue un « laboratoire naturel » pour l’étude des interactions CO2/fluides/roches et des mécanismes de migration du CO2 vers la surface, à l’échelle des temps géologiques. Le caractère particulièrement émissif de cet « analogue » permet également de tester et valider des méthodes de mesure et

  4. A multi-tracer approach to delineate groundwater dynamics in the Rio Actopan Basin, Veracruz State, Mexico

    Science.gov (United States)

    Pérez Quezadas, Juan; Heilweil, Victor M.; Cortés Silva, Alejandra; Araguas, Luis; Salas Ortega, María del Rocío

    2016-07-01

    Geochemistry and environmental tracers were used to understand groundwater resources, recharge processes, and potential sources of contamination in the Rio Actopan Basin, Veracruz State, Mexico. Total dissolved solids are lower in wells and springs located in the basin uplands compared with those closer to the coast, likely associated with rock/water interaction. Geochemical results also indicate some saltwater intrusion near the coast and increased nitrate near urban centers. Stable isotopes show that precipitation is the source of recharge to the groundwater system. Interestingly, some high-elevation springs are more isotopically enriched than average annual precipitation at higher elevations, indicating preferential recharge during the drier but cooler winter months when evapotranspiration is reduced. In contrast, groundwater below 1,200 m elevation is more isotopically depleted than average precipitation, indicating recharge occurring at much higher elevation than the sampling site. Relatively cool recharge temperatures, derived from noble gas measurements at four sites (11-20 °C), also suggest higher elevation recharge. Environmental tracers indicate that groundwater residence time in the basin ranges from 12,000 years to modern. While this large range shows varying groundwater flowpaths and travel times, ages using different tracer methods (14C, 3H/3He, CFCs) were generally consistent. Comparing multiple tracers such as CFC-12 with CFC-113 indicates piston-flow to some discharge points, yet binary mixing of young and older groundwater at other points. In summary, groundwater within the Rio Actopan Basin watershed is relatively young (Holocene) and the majority of recharge occurs in the basin uplands and moves towards the coast.

  5. A multi-tracer approach to delineate groundwater dynamics in the Rio Actopan Basin, Veracruz State, Mexico

    Science.gov (United States)

    Pérez Quezadas, Juan; Heilweil, Victor M.; Cortés Silva, Alejandra; Araguas, Luis; Salas Ortega, María del Rocío

    2016-12-01

    Geochemistry and environmental tracers were used to understand groundwater resources, recharge processes, and potential sources of contamination in the Rio Actopan Basin, Veracruz State, Mexico. Total dissolved solids are lower in wells and springs located in the basin uplands compared with those closer to the coast, likely associated with rock/water interaction. Geochemical results also indicate some saltwater intrusion near the coast and increased nitrate near urban centers. Stable isotopes show that precipitation is the source of recharge to the groundwater system. Interestingly, some high-elevation springs are more isotopically enriched than average annual precipitation at higher elevations, indicating preferential recharge during the drier but cooler winter months when evapotranspiration is reduced. In contrast, groundwater below 1,200 m elevation is more isotopically depleted than average precipitation, indicating recharge occurring at much higher elevation than the sampling site. Relatively cool recharge temperatures, derived from noble gas measurements at four sites (11-20 °C), also suggest higher elevation recharge. Environmental tracers indicate that groundwater residence time in the basin ranges from 12,000 years to modern. While this large range shows varying groundwater flowpaths and travel times, ages using different tracer methods (14C, 3H/3He, CFCs) were generally consistent. Comparing multiple tracers such as CFC-12 with CFC-113 indicates piston-flow to some discharge points, yet binary mixing of young and older groundwater at other points. In summary, groundwater within the Rio Actopan Basin watershed is relatively young (Holocene) and the majority of recharge occurs in the basin uplands and moves towards the coast.

  6. Geochemical landscape strategy in monitoring the areas contaminated by the Chernobyl radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Korobova, E.M.; Linnik, V.G. (Department of Geoinformation Investigations, Russian Scientific-Practical and Expert-Analytical Centre (RNEC), Moscow (Russian Federation))

    1993-12-01

    The Chernobyl accident led to radionuclide contamination of vast areas that now need to be monitored; the development of a regional land use strategy is now needed. Landscape geochemistry enables us to structure, classify and map the environmental factors responsible for the redistribution of radionuclides (i.e. soil-forming rocks and soil properties, vegetation cover, types of ground water migration, and vertical and lateral geochemical barriers). Combined with land use information, regional geochemical landscape maps serve as the basis to map in toposequence conditions of mass migration and accumulation in natural and cultivated landscapes. Such mapping makes it easier to choose representative monitoring sites. This type of mapping is also helpful to interrelate and extrapolate the data already obtained on radionuclides' environmental migration for different groups of geochemical landscapes with similar types of contamination, migration and accumulation patterns. A geochemical landscape approach is demonstrated using the example of part of the Bryansk region (Russia), which is considerably contaminated with [sup 134]Cs and [sup 137]Cs.

  7. On the linearity of tracer bias around voids

    Science.gov (United States)

    Pollina, Giorgia; Hamaus, Nico; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2017-07-01

    The large-scale structure of the Universe can be observed only via luminous tracers of the dark matter. However, the clustering statistics of tracers are biased and depend on various properties, such as their host-halo mass and assembly history. On very large scales, this tracer bias results in a constant offset in the clustering amplitude, known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centred on cosmic voids, i.e. depressions of the density field that spatially dominate the Universe. We consider three types of tracers: galaxies, galaxy clusters and active galactic nuclei, extracted from the hydrodynamical simulation Magneticum Pathfinder. In contrast to common clustering statistics that focus on auto-correlations of tracers, we find that void-tracer cross-correlations are successfully described by a linear bias relation. The tracer-density profile of voids can thus be related to their matter-density profile by a single number. We show that it coincides with the linear tracer bias extracted from the large-scale auto-correlation function and expectations from theory, if sufficiently large voids are considered. For smaller voids we observe a shift towards higher values. This has important consequences on cosmological parameter inference, as the problem of unknown tracer bias is alleviated up to a constant number. The smallest scales in existing data sets become accessible to simpler models, providing numerous modes of the density field that have been disregarded so far, but may help to further reduce statistical errors in constraining cosmology.

  8. SPHRAY: A Smoothed Particle Hydrodynamics Ray Tracer for Radiative Transfer

    Science.gov (United States)

    Altay, Gabriel; Croft, Rupert A. C.; Pelupessy, Inti

    2011-03-01

    SPHRAY, a Smoothed Particle Hydrodynamics (SPH) ray tracer, is designed to solve the 3D, time dependent, radiative transfer (RT) equations for arbitrary density fields. The SPH nature of SPHRAY makes the incorporation of separate hydrodynamics and gravity solvers very natural. SPHRAY relies on a Monte Carlo (MC) ray tracing scheme that does not interpolate the SPH particles onto a grid but instead integrates directly through the SPH kernels. Given initial conditions and a description of the sources of ionizing radiation, the code will calculate the non-equilibrium ionization state (HI, HII, HeI, HeII, HeIII, e) and temperature (internal energy/entropy) of each SPH particle. The sources of radiation can include point like objects, diffuse recombination radiation, and a background field from outside the computational volume. The MC ray tracing implementation allows for the quick introduction of new physics and is parallelization friendly. A quick Axis Aligned Bounding Box (AABB) test taken from computer graphics applications allows for the acceleration of the raytracing component. We present the algorithms used in SPHRAY and verify the code by performing all the test problems detailed in the recent Radiative Transfer Comparison Project of Iliev et. al. The Fortran 90 source code for SPHRAY and example SPH density fields are made available online.

  9. Quantitative observation of tracer transport with high-resolution PET

    Science.gov (United States)

    Kulenkampff, Johannes; Gruendig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-04-01

    Transport processes in natural porous media are typically heterogeneous over various scales. This heterogeneity is caused by the complexity of pore geometry and molecular processes. Heterogeneous processes, like diffusive transport, conservative advective transport, mixing and reactive transport, can be observed and quantified with quantitative tomography of tracer transport patterns. Positron Emission Tomography (PET) is by far the most sensitive method and perfectly selective for positron-emitting radiotracers, therefore it is suited as reference method for spatiotemporal tracer transport observations. The number of such PET-applications is steadily increasing. However, many applications are afflicted by the low spatial resolution (3 - 5 mm) of the clinical scanners from cooperating nuclear medical departments. This resolution is low in relation to typical sample dimensions of 10 cm, which are restricted by the mass attenuation of the material. In contrast, our GeoPET-method applies a high-resolution scanner with a resolution of 1 mm, which is the physical limit of the method and which is more appropriate for samples of the size of soil columns or drill cores. This higher resolution is achieved at the cost of a more elaborate image reconstruction procedure, especially considering the effects of Compton scatter. The result of the quantitative image reconstruction procedure is a suite of frames of the quantitative tracer distribution with adjustable frame rates from minutes to months. The voxel size has to be considered as reference volume of the tracer concentration. This continuous variable includes contributions from structures far below the spatial resolution, as far as a detection threshold, in the pico-molar range, is exceeded. Examples from a period of almost 10 years (Kulenkampff et al. 2008a, Kulenkampff et al. 2008b) of development and application of quantitative GeoPET-process tomography are shown. These examples include different transport processes

  10. B and Li isotopes as intrinsic tracers for injection tests in aquifer storage and recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Kloppmann, Wolfram, E-mail: w.kloppmann@brgm.fr [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Chikurel, Haim [Mekorot National Water Company, Tel Aviv (Israel); Picot, Geraldine [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Guttman, Joseph [Mekorot National Water Company, Tel Aviv (Israel); Pettenati, Marie [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Aharoni, Avi [Mekorot National Water Company, Tel Aviv (Israel); Guerrot, Catherine; Millot, Romain; Gaus, Irina [BRGM, French Geological Survey, 3 Av. Claude Guillemin B.P. 6009, F-45000 Orleans (France); Wintgens, Thomas [Rheinisch Westfaelische Technische Hochschule, RWTH, Aachen (Germany)

    2009-07-15

    Boron and Li isotopes have been tested as environmental tracers of treated sewage injected into a sandy aquifer (Shafdan reclamation project, Israel). During a 38 days injection test in a newly dug injection well, a conservative artificial tracer (Br{sup -}) was monitored together with {delta}{sup 11}B and {delta}{sup 7}Li in the injectate, in the unsaturated soil zone (porous cup) and an observation well in the aquifer. In spite of B and Li concentrations in the injectate close to background values, significant shifts of the isotope signatures could be observed over the duration of the injection test. Boron isotope ratios show a breakthrough curve delayed with respect to Br{sup -} breakthrough due to some reversible sorption on the aquifer material. No isotope fractionation was observed in the unsaturated or the saturated zone so that B isotopes can be considered as conservative in the investigated part of the aquifer system. Lithium isotopes are strongly fractionated, probably due to sorption processes. Lithium concentrations point to a Li sink in the system, {delta}{sup 7}Li values vary strongly with a tendency of {sup 7}Li depletion in the liquid phase over the duration of the experiment. This is opposite to the expected preferential sorption of {sup 6}Li onto clay minerals. Boron isotopes reveals a valuable tracer of artificial recharge of freshwaters derived from treated sewage, both for short term tracer tests and for long-term monitoring of artificial recharge, even if in aquifers with higher clay contents, sorption-linked isotope fractionation cannot be excluded. More data are needed on Li isotope fractionation in natural groundwater systems to assess the potential of this tracer as monitoring tool.

  11. A state space transformation can yield identifiable models for tracer kinetic studies with enrichment data.

    Science.gov (United States)

    Ramakrishnan, Rajasekhar; Ramakrishnan, Janak D

    2010-11-01

    Tracer studies are analyzed almost universally by multicompartmental models where the state variables are tracer amounts or activities in the different pools. The model parameters are rate constants, defined naturally by expressing fluxes as fractions of the source pools. We consider an alternative state space with tracer enrichments or specific activities as the state variables, with the rate constants redefined by expressing fluxes as fractions of the destination pools. Although the redefinition may seem unphysiological, the commonly computed fractional synthetic rate actually expresses synthetic flux as a fraction of the product mass (destination pool). We show that, for a variety of structures, provided the structure is linear and stationary, the model in the enrichment state space has fewer parameters than that in the activities state space, and is hence better both to study identifiability and to estimate parameters. The superiority of enrichment modeling is shown for structures where activity model unidentifiability is caused by multiple exit pathways; on the other hand, with a single exit pathway but with multiple untraced entry pathways, activity modeling is shown to be superior. With the present-day emphasis on mass isotopes, the tracer in human studies is often of a precursor, labeling most or all entry pathways. It is shown that for these tracer studies, models in the activities state space are always unidentifiable when there are multiple exit pathways, even if the enrichment in every pool is observed; on the other hand, the corresponding models in the enrichment state space have fewer parameters and are more often identifiable. Our results suggest that studies with labeled precursors are modeled best with enrichments.

  12. Geochemical arguments for an Earth-like Moon-forming impactor

    OpenAIRE

    Dauphas, Nicolas; Burkhardt, Christoph; Warren, Paul H.; Fang-Zhen, Teng

    2014-01-01

    Geochemical evidence suggests that the material accreted by the Earth did not change in nature during Earth's accretion, presumably because the inner protoplanetary disc had uniform isotopic composition similar to enstatite chondrites, aubrites and ungrouped achondrite NWA 5363/5400. Enstatite meteorites and the Earth were derived from the same nebular reservoir but diverged in their chemical evolutions, so no chondrite sample in meteorite collections is representative of the Earth's building...

  13. A geochemical perspective of Red Mountain: an unmined volcanogenic massive sulfide deposit in the Alaska Range

    Science.gov (United States)

    Giles, Stuart A.; Eppinger, Robert G.

    2014-01-01

    The U.S. Geological Survey (USGS) has investigated the environmental geochemistry of a group of unmined volcanogenic massive sulfide (VMS) deposits in the Bonnifield mining district, Alaska Range, east-central Alaska. The spectacularly colored Red Mountain deposit is the best exposed of these and provides excellent baseline geochemical data for natural environmental impacts of acidic rock drainage, metal dissolution and transport, and acidic salt and metal precipitation from an exposed and undisturbed VMS deposit.

  14. Star clusters as tracers of galaxy evolution

    CERN Document Server

    Konstantopoulos, Iraklis S

    2009-01-01

    Star clusters represent the most common 'mode' of star formation. They are found in all types of environments, cascading down from galaxy groups and merging pairs through starbursts to normal galaxies and dwarves and even isolated regions in extragalactic space. As they maintain a link to the overall star formation in a system, they can be used as tracers of the star formation history of environments located at distances prohibitive to the study of individual stars. This makes them ideally suited to the study of mergers and interactions in galaxy pairs and groups. In this work we present observations of the star cluster populations in the local starburst galaxy M82, post-interaction spiral NGC 6872, the "Antennae" merging pair and two compact groups, "Stephan's Quintet" and HCG 7. In each case, we extract information on the clusters and their hosts using mainly HST photometry and Gemini spectroscopy.

  15. Elemental tracers for Chinese source dust

    Institute of Scientific and Technical Information of China (English)

    张小曳; 张光宇; 朱光华; 张德二; 安芷生; 陈拓; 黄湘萍

    1996-01-01

    The mass-particle size distributions of 10 dust-carrying elements in aerosol particles were determined tor 12 sites in desert regions of northern China. The desert dust is proved to he of origin of eolian loess deposited on the Loess Plateau. Their transport to the loess was mainly attributable to the non-dust storm processes under the interglacial climate condition. The impact ot" dust storm on the accumulation of the loess increased in the glacial stage. On the basis of the signatures of 4 dust elements (Al. Fe, Mg and Sc). Chinese dust is believed to have 3 major desert sources (northwestern deserts, northern high dust deserts and northern low dust deserts). With a chemical element balance model, an elemental tracer system is established to proportion the export of China-source dust.

  16. Tracer studies of nitrogen assimilation in yeast.

    Science.gov (United States)

    ABRAMS, R; HAMMARSTEN, E

    1949-01-01

    By using N(15) as a tracer the assimilation of ammonia by the yeast, Torulopsis utilis, has been studied. It has been shown that: 1. There was no measurable incorporation of N in the protein or polynucleotide purine of carbon-starved yeast. 2. When ammonia is added to nitrogen-starved yeast there is a long lag period before division begins during which the yeast rapidly synthesizes protein, this process being accompanied by a turnover of polynucleotide purine. There was no significant dilution of the N(15)H(4) (+) of the medium by ordinary NH(4) (+). 3. When yeast containing N(15) is allowed to divide and grow in ordinary ammonia, the total amount of N(15) in the yeast remains constant. The dicarboxylic amino acids are most diluted, while arginine and nucleic acid guanine are not diluted at all.

  17. National Biomedical Tracer Facility. Project definition study

    Energy Technology Data Exchange (ETDEWEB)

    Schafer, R.

    1995-02-14

    We request a $25 million government-guaranteed, interest-free loan to be repaid over a 30-year period for construction and initial operations of a cyclotron-based National Biomedical Tracer Facility (NBTF) in North Central Texas. The NBTF will be co-located with a linear accelerator-based commercial radioisotope production facility, funded by the private sector at approximately $28 million. In addition, research radioisotope production by the NBTF will be coordinated through an association with an existing U.S. nuclear reactor center that will produce research and commercial radioisotopes through neutron reactions. The combined facilities will provide the full range of technology for radioisotope production and research: fast neutrons, thermal neutrons, and particle beams (H{sup -}, H{sup +}, and D{sup +}). The proposed NBTF facility includes an 80 MeV, 1 mA H{sup -} cyclotron that will produce proton-induced (neutron deficient) research isotopes.

  18. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers

    Science.gov (United States)

    Matthews, James C.; Bacak, Asan; Khan, M. Anwar H.; Wright, Matthew D.; Priestley, Michael; Martin, Damien; Percival, Carl J.; Shallcross, Dudley E.

    2017-01-01

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO2 tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants. PMID:28230812

  19. Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers.

    Science.gov (United States)

    Matthews, James C; Bacak, Asan; Khan, M Anwar H; Wright, Matthew D; Priestley, Michael; Martin, Damien; Percival, Carl J; Shallcross, Dudley E

    2017-02-21

    People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO₂ tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants.

  20. On the linearity of tracer bias around voids

    CERN Document Server

    Pollina, Giorgia; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2016-01-01

    The large-scale structure of the universe can only be observed directly via luminous tracers of the underlying distribution of dark matter. However, the clustering statistics of tracers are biased and depend on various properties of the tracers themselves, such as their host-halo mass and formation and assembly history. On very large scales, where density fluctuations are within the linear regime, this tracer bias results in a constant offset in the clustering amplitude, which is known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centered on cosmic voids, depressions of the density field that spatially dominate the universe. We consider three different types of tracers: galaxies, galaxy clusters and AGNs, extracted from the hydrodynamical simulation suite Magneticum Pathfinder. In contrast to common clustering statistics that focus on the auto-correlation of tracers, we find that void-tra...

  1. Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

    Directory of Open Access Journals (Sweden)

    S. B. Joye

    2005-05-01

    Full Text Available Geophysical, temperature, and discrete depth-stratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and sub-bottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10°C warmer than the bottom water. At the brine pool, two thermoclines were observed, one directly below the brine-seawater interface and a second about one meter below the first. At the mud volcano, substantial temperature variability was observed, with the core brine temperature being either slightly (~2°C in 1997 or substantially (19°C in 1998 elevated above bottom water temperature. Geochemical samples were obtained using a device called the "brine trapper" and concentrations of dissolved gases, major ions and nutrients were determined using standard techniques. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggests that the fluids are derived from different sources or that brine-sediment reactions are more important at the mud volcano than the brine pool. Substantial concentrations of methane and ammonium were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of methane and dissolved inorganic nitrogen to the surrounding environment.

  2. Geophysical and geochemical signatures of Gulf of Mexico seafloor brines

    Directory of Open Access Journals (Sweden)

    S. B. Joye

    2005-01-01

    Full Text Available Geophysical, temperature, and discrete depth-stratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and sub-bottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10°C warmer than the bottom water. At the brine pool, thermal stratification was observed and only small differences in stratification were documented between three sampling times (1991, 1997 and 1998. In contrast, at the mud volcano, substantial temperature variability was observed, with the core brine temperature being slightly higher than bottom water (by 2°C in 1997 but substantially higher than bottom water (by 19°C in 1998. Detailed geochemical samples were obtained in 2002 using a device called the 'brine trapper' and concentrations of dissolved gases, major ions and nutrients were determined. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggest that the fluids are derived from different sources, have different dilution/mixing histories, or that brine-sediment reactions are more important at the mud volcano. Substantial concentrations of methane, ammonium, and silicate were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of these constituents to the surrounding environment.

  3. Geochemical patterns in the soils of Cyprus.

    Science.gov (United States)

    Cohen, David R; Rutherford, Neil F; Morisseau, Eleni; Zissimos, Andreas M

    2012-03-15

    The soil geochemical atlas of Cyprus is a recent addition to the series of national to continental-scale geochemical mapping programmes implemented over the last two decades for environmental and resource applications. The study has been conducted at the high sampling density of 1 site per 1km(2), with multi-element and multi-method analysis performed on samples of top soil (0-25cm) and sub soil (50-75cm) from a grid of over 5350 sites across a major portion of Cyprus. Major and most trace elements display sharp concentration changes across the main geological boundaries but a high degree of spatial continuity and consistency of values within those boundaries. Some elements display one to two orders of magnitude difference in median concentrations between the soils developed over ultramafic or mafic units and those developed over sedimentary rocks or alluvial units. The ratio of aqua regia-extractable to total metal contents provides an indication of the general mineralogical host for a number of trace elements. The majority of soils are near-neutral to alkaline with the small proportion of areas with soil pHgeochemical values. Where the concentrations of some elements (including Pb, Hg and Sn) are indicative of contamination, the values are typically higher in the top soil samples in these areas. Variations in the concentration of elements with strong redox controls on mobility are linked to changes in sedimentary environment between deep and shallow marine conditions. Some element patterns can be related to the effects of urbanisation and sulphide mining operations; however the dominant control on soil geochemistry is the parent geology and regolith forming processes. The atlas demonstrates the effectiveness of high-density sampling in mapping local to regional-scale features of the geochemical landscape.

  4. DNA-based methods of geochemical prospecting

    Science.gov (United States)

    Ashby, Matthew

    2011-12-06

    The present invention relates to methods for performing surveys of the genetic diversity of a population. The invention also relates to methods for performing genetic analyses of a population. The invention further relates to methods for the creation of databases comprising the survey information and the databases created by these methods. The invention also relates to methods for analyzing the information to correlate the presence of nucleic acid markers with desired parameters in a sample. These methods have application in the fields of geochemical exploration, agriculture, bioremediation, environmental analysis, clinical microbiology, forensic science and medicine.

  5. Quantifying groundwater travel time near managed recharge operations using 35S as an intrinsic tracer

    Science.gov (United States)

    Urióstegui, Stephanie H.; Bibby, Richard K.; Esser, Bradley K.; Clark, Jordan F.

    2016-12-01

    Identifying groundwater retention times near managed aquifer recharge (MAR) facilities is a high priority for managing water quality, especially for operations that incorporate recycled wastewater. To protect public health, California guidelines for Groundwater Replenishment Reuse Projects require a minimum 2-6 month subsurface retention time for recycled water depending on the level of disinfection, which highlights the importance of quantifying groundwater travel times on short time scales. This study developed and evaluated a new intrinsic tracer method using the naturally occurring radioisotope sulfur-35 (35S). The 87.5 day half-life of 35S is ideal for investigating groundwater travel times on the managers. Natural concentrations of 35S found in water as dissolved sulfate (35SO4) were measured in source waters and groundwater at the Rio Hondo Spreading Grounds in Los Angeles County, CA, and Orange County Groundwater Recharge Facilities in Orange County, CA. 35SO4 travel times are comparable to travel times determined by well-established deliberate tracer studies. The study also revealed that 35SO4 in MAR source water can vary seasonally and therefore careful characterization of 35SO4 is needed to accurately quantify groundwater travel time. More data is needed to fully assess whether or not this tracer could become a valuable tool for managers.

  6. Methods and systems using encapsulated tracers and chemicals for reservoir interrogation and manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Jeffery; Aines, Roger D; Duoss, Eric B; Spadaccini, Christopher M

    2014-11-04

    An apparatus, method, and system of reservoir interrogation. A tracer is encapsulating in a receptacle. The receptacle containing the tracer is injected into the reservoir. The tracer is analyzed for reservoir interrogation.

  7. Solute movement in drained fen peat: a field tracer study in a Somerset (UK) wetland

    Science.gov (United States)

    Baird, Andrew J.; Gaffney, Simon W.

    2000-10-01

    Little is known about solute transport in peats, despite the obvious importance of solute transport on eco-hydrological processes in both managed and natural peatlands. To address this lack of knowledge, we investigated solute transport processes in an agricultural fen peat using a conservative KBr tracer. The main aim of the study was to elucidate solute transport behaviour in general in this peat, with a more specific aim of investigating whether preferential or bypassing flow occurred. The tracer moved through the peat more rapidly than expected, and the pattern of movement showed clear evidence of plot-scale bypassing flow. The data also provide evidence that bypassing flow occurs in pores at smaller scales. The implications of this study for management of wetland pastures in the Somerset Moors in south-west England are discussed.

  8. Evaluation of Geochemical Fracture Conductivity Alterations in Shale under Laboratory Conditions

    Science.gov (United States)

    Radonjic, M.; Olabode, A.

    2015-12-01

    . The result indicated that rock-fluid geochemical interactions can constrict natural fracture conductivity under CO2 sequestration conditions. This diagenetic accretions can lead to significant improvement in the seal integrity of shaly caprocks.

  9. Geochemical orientation for mineral exploration in the Hashemite Kingdom of Jordan

    Science.gov (United States)

    Overstreet, W.C.; Grimes, D.J.; Seitz, J.F.

    1982-01-01

    This report is a supplement to previous accounts of geochemical exploration conducted in the Hashemite Kingdom of Jordan by the Natural Resources Authority of the Royal Government of Jordan and the U.S. Geological Survey. The field work on which this report is based was sponsored by the U.S. Agency for International Development, U.S. Department of State. Procedures used in collecting various kinds of rocks, ores, slags, eluvial and alluvial sediments, heavy-mineral concentrates, and organic materials for use as geochemical sample media are summarized, as are the laboratory procedures followed for the analysis of these sample materials by semiquantitative spectrographic, atomic absorption, fluorometric, and X-ray diffraction methods. Geochemical evaluations of the possibilities for economic mineral deposits in certain areas are presented. The results of these preliminary investigations open concepts for further use in geochemical exploration in the search for metallic mineral deposits in Jordan. Perhaps the most desirable new activity would be hydrogeochemical exploration for uranium and base metals, accompanied by interpretation of such remote-sensing data as results of airborne radiometric surveys and computer-enhanced LANDSAT imagery. For more conventional approaches to geochemical exploration, however, several fundamental problems regarding proper choice of geochemical sample media for different geologic and geographic parts of the Country must be solved before effective surveys can be made. The present results also show that such common geochemical exploration techniques as the determination of the trace-element contents of soils, plant ash, and slags have direct application also toward the resolution of several archaeological problems in Jordan. These include the relation of trace-elements chemistry of local soils to the composition of botanic remains, the trace-elements composition of slags to the technological development of the extractive metallurgy of

  10. Environment tracers application to groundwater circulation assessment in an alluvial aquifer in Central Italy

    Science.gov (United States)

    Sappa, Giuseppe; Barbieri, Maurizio; Vitale, Stefania

    2017-04-01

    Groundwater vulnerability assessment is an important tool in order to plan any groundwater protection strategy. The aim of this study is to experiment a specific approach to give a conceptual model about groundwater circulation characterization. This approach has been applied to a suspected contaminated site in a large alluvial plan, made of sediments coming from weathered volcanic rocks, laying on marine sediments, where more than thirty years ago had been built a very important urban waste solid landfill. In referring to this case history it has been pointed out the importance of natural chemical interaction between ground water and rock mass, especially when pyroclastic origin sediments are involved. The landfill had been isolated from the surrounding environment, especially to protect aquifers, by a waterproof diaphragm This land is characterised by intensive agricultural and industrial activities (oil refineries, medical waste incinerators, concrete production, tar factory). The study will highlight the importance of environmental tracers which provide information about the flow and mixing processes of water coming from different sources. They are also useful to point out directions of groundwater flow and to determine origin Environmental tracers are natural chemical and isotopic substances that can be measured in groundwater and used to understand hydrologic properties of aquifers. They may be input into the hydrological system from the atmosphere at recharge and/or are added/lost/exchanged inherently as waters flow over and through materials. Variations in their chemical abundances and isotopic compositions can be used as tracers to determine sources (provenance), pathways (of reaction or interaction) and also timescales (dating) of environmental processes. In combination with these, the basic idea is to use. In this case enviromental tracers have been integrated by temperature and electric conductivity logs, to better investigate different levels of faster

  11. The geochemical atlas of Italian soils

    Science.gov (United States)

    De Vivo, Benedetto; Cicchella, Domenico; Albanese, Stefano; Dinelli, Enrico; Giaccio, Lucia; Lima, Annamaria; Valera, Paolo

    2014-05-01

    The geochemical Atlas of Italian agricultural and grazing land soils was carried out as part of GEMAS project whose objective was to characterize soils of rural areas of the whole Europe. Soil samples were collected at an average sampling density of 1 site per 2500 km2. Two different sample types were collected: (1) 121 agricultural soils (Ap) on regularly ploughed land to a depth of 20 cm and (2) 121 grazing land soils (Gr) (land under permanent grass cover) to a depth of 10 cm. All soil samples were air dried, sieved to pH, TOC, total carbon and total sulphur, LOI, CEC, Sr-isotopes, Pb-isotopes, MIR-spectra. By means of a GIS software, georeferenced data of the Italian territory were used to produce the geochemical maps of all the analysed elements for both agricultural and grazing land soils. Specifically, for each element and sampling media a map reporting interpolated data and graduated dots was produced; univariate statistics and graphs were also associated to each map. The Atlas also contain: 5 maps for regional variability of factor scores of elemental associations resulting from R-mode factor analysis and 15 baseline and land use maps for some selected elements (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, V, Zn) following the Italian intervention criteria.

  12. Geochemical baseline data, Youngs Bay, Oregon, 1974

    Energy Technology Data Exchange (ETDEWEB)

    McMechan, K.J. (ed.); Johnson, V.G.; Cutshall, N.H.

    1975-04-01

    This report comprises one part of a final report to the Alumax Pacific Aluminum Corporation on the Physical, Chemical and Biological Studies of Youngs Bay''. The data reported herein are the product of the geochemical baseline section of the project. The primary objectives of the geochemical study were: to provide a baseline record of fluoride and selected trace metal levels in Youngs Bay bottom sediment, to identify areas that might function as heavy metal traps, to attempt to determine the recent depositional history of sediment in the bay. In addition to these primary objectives, a number of secondary tasks were undertaken during the study. While time did not allow these additional studies to be carried to completion, preliminary results are included herein because of their potential usefulness in assessing the impact of environmental releases of fluoride to aquatic systems in the vicinity of Youngs Bay or elsewhere. This report is made up of two major sections. In the first, a description of sample collection and analytical procedures is followed by a discussion of the baseline results. Obvious vertical and horizontal patterns of elemental distribution are identified and their origins considered. Problems needed further research are also discussed. In the second section, the data are presented in interpretive, graphical form, as well as in tables. 35 refs., 29 figs., 14 tabs.

  13. Is formamide a geochemically plausible prebiotic solvent?

    Science.gov (United States)

    Bada, Jeffrey L; Chalmers, John H; Cleaves, H James

    2016-07-27

    From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

  14. Geochemical and geophysical examination of submarine groundwater discharge and associated nutrient loading estimates into Lynch Cove, Hood Canal, WA

    Science.gov (United States)

    Swarzenski, P.W.; Simonds, F.W.; Paulson, A.J.; Kruse, S.; Reich, C.

    2007-01-01

    Geochemical tracer data (i.e., 222Rn and four naturally occurring Ra isotopes), electromagnetic (EM) seepage meter results, and high-resolution, stationary electrical resistivity images were used to examine the bi-directional (i.e., submarine groundwater discharge and recharge) exchange of a coastal aquifer with seawater. Our study site for these experiments was Lynch Cove, the terminus of Hood Canal, WA, where fjord-like conditions dramatically limit water column circulation that can lead to recurring summer-time hypoxic events. In such a system a precise nutrient budget may be particularly sensitive to groundwater-derived nutrient loading. Shore-perpendicular time-series subsurface resistivity profiles show clear, decimeter-scale tidal modulation of the coastal aquifer in response to large, regional hydraulic gradients, hydrologically transmissive glacial terrain, and large (4-5 m) tidal amplitudes. A 5-day 222Rn time-series shows a strong inverse covariance between 222Rn activities (0.5−29 dpm L-1) and water level fluctuations, and provides compelling evidence for tidally modulated exchange of groundwater across the sediment/water interface. Mean Rn-derived submarine groundwater discharge (SGD) rates of 85 ± 84 cm d-1 agree closely in the timing and magnitude with EM seepage meter results that showed discharge during low tide and recharge during high tide events. To evaluate the importance of fresh versus saline SGD, Rn-derived SGD rates (as a proxy of total SGD) were compared to excess 226Ra-derived SGD rates (as a proxy for the saline contribution of SGD). The calculated SGD rates, which include a significant (>80%) component of recycled seawater, are used to estimate associated nutrient (NH4+, Si, PO43-, NO3 + NO2, TDN) loads to Lynch Cove. The dissolved inorganic nitrogen (DIN = NH4 + NO2 + NO3) SGD loading estimate of 5.9 × 104 mol d-1 is 1−2 orders of magnitude larger than similar estimates derived from atmospheric deposition and surface water runoff

  15. Geochemical and geophysical examination of submarine groundwater discharge and associated nutrient loading estimates into Lynch Cove, Hood Canal, WA.

    Science.gov (United States)

    Swarzenski, Peter W; Simonds, F William; Paulson, Anthony J; Kruse, Sarah; Reich, Chris

    2007-10-15

    Geochemical tracer data (i.e., 222Rn and four naturally occurring Ra isotopes), electromagnetic (EM) seepage meter results, and high-resolution, stationary electrical resistivity images were used to examine the bi-directional (i.e., submarine groundwater discharge and recharge) exchange of a coastal aquifer with seawater. Our study site for these experiments was Lynch Cove, the terminus of Hood Canal, WA, where fjord-like conditions dramatically limit water column circulation that can lead to recurring summer-time hypoxic events. In such a system a precise nutrient budget may be particularly sensitive to groundwater-derived nutrient loading. Shore-perpendicular time-series subsurface resistivity profiles show clear, decimeter-scale tidal modulation of the coastal aquifer in response to large, regional hydraulic gradients, hydrologically transmissive glacial terrain, and large (4-5 m) tidal amplitudes. A 5-day 222Rn time-series shows a strong inverse covariance between 222Rn activities (0.5-29 dpm L(-1)) and water level fluctuations, and provides compelling evidence for tidally modulated exchange of groundwater across the sediment/water interface. Mean Rn-derived submarine groundwater discharge (SGD) rates of 85 +/- 84 cm d(-1) agree closely in the timing and magnitude with EM seepage meter results that showed discharge during low tide and recharge during high tide events. To evaluate the importance of fresh versus saline SGD, Rn-derived SGD rates (as a proxy of total SGD) were compared to excess 226Ra-derived SGD rates (as a proxy for the saline contribution of SGD). The calculated SGD rates, which include a significant (>80%) component of recycled seawater, are used to estimate associated nutrient (NH4+, Si, PO4(3-), NO3 + NO2, TDN) loads to Lynch Cove. The dissolved inorganic nitrogen (DIN = NH4 + NO2 + NO3) SGD loading estimate of 5.9 x 10(4) mol d(-1) is 1-2 orders of magnitude larger than similar estimates derived from atmospheric deposition and surface water

  16. Germanium-silicon as a flow path tracer: Application to the Rio Icacos watershed

    Science.gov (United States)

    Kurtz, Andrew C.; Lugolobi, Festo; Salvucci, Guido

    2011-06-01

    We use dissolved silicon together with its "geochemical twin" germanium for the first time as a hydrologic tracer to study water delivery to the stream during storm events in the Rio Icacos watershed, Puerto Rico. Ge and Si were measured on base flow, stormflow, springwater, and soil water samples. Compositions of all of these waters appear to reflect varying contributions from three components, which we attribute to solutes released from bedrock weathering (groundwater), from short-term soil-water interaction (quick soil water), and longer-term soil-water interaction (matrix soil water). Base flow stream waters have high Si and moderate Ge (Ge/Si ratio ˜0.29 μmol/mol), consistent with a predominantly bedrock weathering source as indicated by their similarity with water sampled from springs emerging from the saprolite-bedrock boundary on a hillslope landslide scar. During storm events there is a shift toward more dilute compositions (but higher Ge/Si ratios) similar to those measured on water samples from temporary depression storage and overland flow (quick soil water). Geochemical mass balance shows that 80%-90% of the stream chemistry can be explained by mixing groundwater with this quick soil water composition, which we infer to reflect new water traveling as shallow throughflow. Stream water δ18O values decrease to more negative values typical of precipitation supporting rapid delivery of rainwater to the stream channel during stormflow. The third component, with a Ge-rich composition characteristic of soil matrix water sampled by tension lysimeters, is required to explain higher stream water Ge/Si ratios measured during hydrograph recession. We infer from this an additional, slower, and less dominant pathway for delivery of soil water to the stream channel.

  17. A geochemical atlas of North Carolina, USA

    Science.gov (United States)

    Reid, J.C.

    1993-01-01

    A geochemical atlas of North Carolina, U.S.A., was prepared using National Uranium Resource Evaluation (NURE) stream-sediment data. Before termination of the NURE program, sampling of nearly the entire state (48,666 square miles of land area) was completed and geochemical analyses were obtained. The NURE data are applicable to mineral exploration, agriculture, waste disposal siting issues, health, and environmental studies. Applications in state government include resource surveys to assist mineral exploration by identifying geochemical anomalies and areas of mineralization. Agriculture seeks to identify areas with favorable (or unfavorable) conditions for plant growth, disease, and crop productivity. Trace elements such as cobalt, copper, chromium, iron, manganese, zinc, and molybdenum must be present within narrow ranges in soils for optimum growth and productivity. Trace elements as a contributing factor to disease are of concern to health professionals. Industry can use pH and conductivity data for water samples to site facilities which require specific water quality. The North Carolina NURE database consists of stream-sediment samples, groundwater samples, and stream-water analyses. The statewide database consists of 6,744 stream-sediment sites, 5,778 groundwater sample sites, and 295 stream-water sites. Neutron activation analyses were provided for U, Br, Cl, F, Mn, Na, Al, V, Dy in groundwater and stream water, and for U, Th, Hf, Ce, Fe, Mn, Na, Sc, Ti, V, Al, Dy, Eu, La, Sm, Yb, and Lu in stream sediments. Supplemental analyses by other techniques were reported on U (extractable), Ag, As, Ba, Be, Ca, Co, Cr, Cu, K, Li, Mg, Mo, Nb, Ni, P, Pb, Se, Sn, Sr, W, Y, and Zn for 4,619 stream-sediment samples. A small subset of 334 stream samples was analyzed for gold. The goal of the atlas was to make available the statewide NURE data with minimal interpretation to enable prospective users to modify and manipulate the data for their end use. The atlas provides only

  18. Evaluation of the transport matrix method for simulation of ocean biogeochemical tracers

    Science.gov (United States)

    Kvale, Karin F.; Khatiwala, Samar; Dietze, Heiner; Kriest, Iris; Oschlies, Andreas

    2017-06-01

    Conventional integration of Earth system and ocean models can accrue considerable computational expenses, particularly for marine biogeochemical applications. Offline numerical schemes in which only the biogeochemical tracers are time stepped and transported using a pre-computed circulation field can substantially reduce the burden and are thus an attractive alternative. One such scheme is the transport matrix method (TMM), which represents tracer transport as a sequence of sparse matrix-vector products that can be performed efficiently on distributed-memory computers. While the TMM has been used for a variety of geochemical and biogeochemical studies, to date the resulting solutions have not been comprehensively assessed against their online counterparts. Here, we present a detailed comparison of the two. It is based on simulations of the state-of-the-art biogeochemical sub-model embedded within the widely used coarse-resolution University of Victoria Earth System Climate Model (UVic ESCM). The default, non-linear advection scheme was first replaced with a linear, third-order upwind-biased advection scheme to satisfy the linearity requirement of the TMM. Transport matrices were extracted from an equilibrium run of the physical model and subsequently used to integrate the biogeochemical model offline to equilibrium. The identical biogeochemical model was also run online. Our simulations show that offline integration introduces some bias to biogeochemical quantities through the omission of the polar filtering used in UVic ESCM and in the offline application of time-dependent forcing fields, with high latitudes showing the largest differences with respect to the online model. Differences in other regions and in the seasonality of nutrients and phytoplankton distributions are found to be relatively minor, giving confidence that the TMM is a reliable tool for offline integration of complex biogeochemical models. Moreover, while UVic ESCM is a serial code, the TMM can

  19. The effect of scale on the interpretation of geochemical anomalies

    Science.gov (United States)

    Theobald, P.K.; Eppinger, R.G.; Turner, R.L.; Shiquan, S.

    1991-01-01

    The purpose of geochemical surveys changes with scale. Regional surveys identify areas where mineral deposits are most likely to occur, whereas intermediate surveys identify and prioritize specific targets. At detailed scales specific deposit models may be applied and deposits delineated. The interpretation of regional geochemical surveys must take into account scale-dependent difference in the nature and objectives of this type of survey. Overinterpretation of regional data should be resisted, as should recommendations to restrict intermediate or detailed follow-up surveys to the search for specific deposit types or to a too limited suite of elements. Regional surveys identify metallogenic provinces within which a variety of deposit types and metals are most likely to be found. At intermediate scale, these regional provinces often dissipate into discrete clusters of anomalous areas. At detailed scale, individual anomalous areas reflect local conditions of mineralization and may seem unrelated to each other. Four examples from arid environments illustrate the dramatic change in patterns of anomalies between regional and more detailed surveys. On the Arabian Shield, a broad regional anomaly reflects the distribution of highly differentiated anorogenic granites. A particularly prominent part of the regional anomaly includes, in addition to the usual elements related to the granites, the assemblage of Mo, W and Sn. Initial interpretation suggested potential for granite-related, stockwork Mo deposits. Detailed work identified three separate sources for the anomaly: a metal-rich granite, a silicified and stockwork-veined area with scheelite and molybdenite, and scheelite/powellite concentrations in skarn deposits adjacent to a ring-dike complex. Regional geochemical, geophysical and remote-sensing data in the Sonoran Desert, Mexico, define a series of linear features interpreted to reflect fundamental, northeast-trending fractures in the crust that served as the prime

  20. An Advanced Reservoir Simulator for Tracer Transport in Multicomponent Multiphase Compositional Flow and Applications to the Cranfield CO2 Sequestration Site

    Science.gov (United States)

    Moortgat, J.

    2015-12-01

    Reservoir simulators are widely used to constrain uncertainty in the petrophysical properties of subsurface formations by matching the history of injection and production data. However, such measurements may be insufficient to uniquely characterize a reservoir's properties. Monitoring of natural (isotopic) and introduced tracers is a developing technology to further interrogate the subsurface for applications such as enhanced oil recovery from conventional and unconventional resources, and CO2 sequestration. Oak Ridge National Laboratory has been piloting this tracer technology during and following CO2 injection at the Cranfield, Mississippi, CO2 sequestration test site. Two campaigns of multiple perfluorocarbon tracers were injected together with CO2 and monitored at two wells at 68 m and 112 m from the injection site. The tracer data suggest that multiple CO2 flow paths developed towards the monitoring wells, indicative of either channeling through high permeability pathways or of fingering. The results demonstrate that tracers provide an important complement to transient pressure data. Numerical modeling is essential to further explain and interpret the observations. To aid the development of tracer technology, we enhanced a compositional multiphase reservoir simulator to account for tracer transport. Our research simulator uses higher-order finite element (FE) methods that can capture the small-scale onset of fingering on the coarse grids required for field-scale modeling, and allows for unstructured grids and anisotropic heterogeneous permeability fields. Mass transfer between fluid phases and phase behavior are modeled with rigorous equation-of-state based phase-split calculations. We present our tracer simulator and preliminary results related to the Cranfield experiments. Applications to noble gas tracers in unconventional resources are presented by Darrah et al.

  1. An Integrated Approach to Characterizing Bypassed Oil in Heterogeneous and Fractured Reservoirs Using Partitioning Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Akhil Datta-Gupta

    2006-12-31

    We explore the use of efficient streamline-based simulation approaches for modeling partitioning interwell tracer tests in hydrocarbon reservoirs. Specifically, we utilize the unique features of streamline models to develop an efficient approach for interpretation and history matching of field tracer response. A critical aspect here is the underdetermined and highly ill-posed nature of the associated inverse problems. We have investigated the relative merits of the traditional history matching ('amplitude inversion') and a novel travel time inversion in terms of robustness of the method and convergence behavior of the solution. We show that the traditional amplitude inversion is orders of magnitude more non-linear and the solution here is likely to get trapped in local minimum, leading to inadequate history match. The proposed travel time inversion is shown to be extremely efficient and robust for practical field applications. The streamline approach is generalized to model water injection in naturally fractured reservoirs through the use of a dual media approach. The fractures and matrix are treated as separate continua that are connected through a transfer function, as in conventional finite difference simulators for modeling fractured systems. A detailed comparison with a commercial finite difference simulator shows very good agreement. Furthermore, an examination of the scaling behavior of the computation time indicates that the streamline approach is likely to result in significant savings for large-scale field applications. We also propose a novel approach to history matching finite-difference models that combines the advantage of the streamline models with the versatility of finite-difference simulation. In our approach, we utilize the streamline-derived sensitivities to facilitate history matching during finite-difference simulation. The use of finite-difference model allows us to account for detailed process physics and compressibility effects

  2. Seasonal distribution and geochemical fractionation of heavy metals from surface sediment in a tropical estuary of Jeneberang River, Indonesia.

    Science.gov (United States)

    Najamuddin; Prartono, Tri; Sanusi, Harpasis S; Nurjaya, I Wayan

    2016-10-15

    Lead (Pb) and zinc (Zn) concentrations from surface sediments were determined at 17 stations in riverine, estuarine, and marine environments during the wet and dry seasons. The geochemical fractionations were obtained by a sequential extraction procedure in five geochemical forms: exchangeable, bound to carbonate, iron-manganese oxide, organic, and residual fractions. The concentrations of Pb and Zn in the water were higher during the wet season than the dry season and higher in the riverine and marine samples than the estuarine samples. Following geochemical fractionation, the metals were found mainly in the residual fraction. The results indicated that the concentrations were influenced by season, with the sources of Pb and Zn derived mainly from rivers and natural sources. The contamination status in the estuary of the Jeneberang River was classified as weak to moderate pollution and the risk level to aquatic biota attributed was no risk to low risk.

  3. The Persistence of Potential Refugia Mapped from Gravel Tracers

    Science.gov (United States)

    Haschenburger, J. K.

    2009-12-01

    Floods disturb aquatic habitats. On an event basis, flood characteristics control the spatial extent and depth of streambed disturbance for a given river and set limits to the amount of channel refugia for biota. The aim of this research is to quantify the area of potential refugia that persists over a long flood series and therefore affects many generations of aquatic populations. Field observations were collected in Carnation Creek, a small gravel-bed river located on the west coast of Vancouver Island, Canada. Streambed disturbance was documented by monitoring the three-dimensional positions of about 2500 magnetically tagged gravels over 277 floods. Tracer movement and burial observations were used to produce cellular maps of the frequency of bed disturbance within a GIS. The streambed exhibits different frequencies of disturbance as expected. The most active areas make up about 1% of the streambed and tend to be located near the channel thalweg. Undisturbed areas constitute more than 25% of the bed, and provide distinct areas of longer-term refugia that persist over the range of flood magnitudes observed. In addition to validating a key aspect of partial sediment transport, the results suggest that the natural variability of floods facilitates diverse aquatic communities by ensuring the availability of channel refugia over time.

  4. Passive galaxies as tracers of cluster environments at z~2

    CERN Document Server

    Strazzullo, V; Gobat, R; Garilli, B; Mignoli, M; Valentino, F; Onodera, M; Renzini, A; Cimatti, A; Finoguenov, A; Arimoto, N; Cappellari, M; Carollo, C M; Feruglio, C; Floc'h, E Le; Lilly, S J; Maccagni, D; McCracken, H J; Moresco, M; Pozzetti, L; Zamorani, G

    2015-01-01

    Even 10 billion years ago, the cores of the first galaxy clusters are often found to host a characteristic population of massive galaxies with already suppressed star formation. Here we search for distant cluster candidates at z~2 using massive passive galaxies as tracers. With a sample of ~40 spectroscopically confirmed passive galaxies at 1.3nature of these concentrations is still to be confirmed, we discuss their identification procedure, and the arguments supporting them as candidate galaxy clusters (likely mid-10^13 M_sun range). Although this search approach is likely biased towards more evolved structures, it has...

  5. Radio-geochemical methods at surface expiotation of oil and gas fields

    OpenAIRE

    Sobolev, I. S.

    2007-01-01

    A review of the situation with radio-geochemical methods of searching oil and gas fields is presented. Potential reasons of radio-geochemical anomalies formation are considered, some approaches to interpretation of radio-geochemical datum are listed

  6. Tracer diffusivity and effective temperature in bacterial suspensions

    CERN Document Server

    Patteson, Alison E; Purohit, Prashant K; Arratia, Paulo E

    2015-01-01

    The dynamics of tracer particles in \\textit{E. coli} suspensions are experimentally investigated as a function of particle size and bacteria concentration. We find that tracer diffusivity is enhanced due to particle-bacteria interactions and varies non-monotonically with particle size, exhibiting a peak at sizes comparable to the bacterial length. The time scale characterizing the transition from ballistic to diffusive regime increases monotonically with \\textit{E. coli} concentration and particle size. Diffusivity measurements are then used to estimate suspension effective temperature, which varies nonlinearly with tracer size, suggesting that measures of activity are probe size dependent.

  7. Radionuclide Tracers for Myocardial Perfusion Imaging and Blood Flow Quantification.

    Science.gov (United States)

    deKemp, Robert A; Renaud, Jennifer M; Klein, Ran; Beanlands, Rob S B

    2016-02-01

    Myocardial perfusion imaging is performed most commonly using Tc-99m-sestamibi or tetrofosmin SPECT as well as Rb-82-rubidium or N-13-ammonia PET. Diseased-to-normal tissue contrast is determined by the tracer retention fraction, which decreases nonlinearly with flow. Reduced tissue perfusion results in reduced tracer retention, but the severity of perfusion defects is typically underestimated by 20% to 40%. Compared to SPECT, retention of the PET tracers is more linearly related to flow, and therefore, the perfusion defects are measured more accurately using N-13-ammonia or Rb-82.

  8. Laboratory Testing of Magnetic Tracers for Soil Erosion Measurement*1

    Institute of Scientific and Technical Information of China (English)

    HU Guo-Qing; DONG Yuan-Jie; WANG Hui; QIU Xian-Kui; WANG Yan-Hua

    2011-01-01

    Soil erosion, which includes soil detachment, transport, and deposition, is one of the important dynamic land surface processes. The magnetic tracer method is a useful method for studying soil erosion processes. In this study, five types of magnetic tracers were made with fine soil, fly ash, cement, bentonite, and magnetic powder (reduced iron powder) using the method of disk granulation. The tracers were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow experiments to simulate the interrill and rill components of soil erosion, in order to select one or more tracers which could be used to study detachment and deposition by the erosive forces of raindrops and surface flow of water on a slope. The results showed that the five types of magnetic tracers with high magnetic susceptibility and a wide range of sizes had a range of 0.99-1.29 gcm-s in bulk density. In the interrill and rill experiments, the tracers FC1 and FC2 which consisted of fly ash and cement at ratios of 1:1 and 2:1, respectively, were transported in phase with soil particles since the magnetic susceptibility of sediment approximated that of the soil which was uneroded and the slopes of the regression equations between the detachment of sediment and magnetic tracers FC1 and FC2 were very close to the expected value of 20, which was the original soil/tracer ratio. The detachment and deposition on slopes could be accurately reflected by the magnetic susceptibility differences. The change in magnetic susceptibility depended on whether deposition or detachment occurred. However, the tracer FS which consisted of fine soil and the tracers FB1 and FB2 which consisted of fly ash and bentonite at ratios of 1:1 and 2:1, respectively, were all unsuitable for soil erosion study since there was no consistent relationship between sediment and tracer detachment for increasing amounts of runoff. Therefore, the tracers FC1 and FC2 could be used to study soil erosion by water.

  9. Selected Geochemical Data for Modeling Near-Surface Processes in Mineral Systems

    Science.gov (United States)

    Giles, Stuart A.; Granitto, Matthew; Eppinger, Robert G.

    2009-01-01

    The database herein was initiated, designed, and populated to collect and integrate geochemical, geologic, and mineral deposit data in an organized manner to facilitate geoenvironmental mineral deposit modeling. The Microsoft Access database contains data on a variety of mineral deposit types that have variable environmental effects when exposed at the ground surface by mining or natural processes. The data tables describe quantitative and qualitative geochemical analyses determined by 134 analytical laboratory and field methods for over 11,000 heavy-mineral concentrate, rock, sediment, soil, vegetation, and water samples. The database also provides geographic information on geology, climate, ecoregion, and site contamination levels for over 3,000 field sites in North America.

  10. NDIR gas sensor for spatial monitoring of carbon dioxide concentrations in naturally ventilated livestock buildings

    NARCIS (Netherlands)

    Mendes, L.B.; Ogink, N.W.M.; Edouard, Nadège; Dooren, van H.J.C.; Tinoco, I.; Mosquera, Julio

    2015-01-01

    The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost

  11. Geochemical Evidence for a Terrestrial Magma Ocean

    Science.gov (United States)

    Agee, Carl B.

    1999-01-01

    The aftermath of phase separation and crystal-liquid fractionation in a magma ocean should leave a planet geochemically differentiated. Subsequent convective and other mixing processes may operate over time to obscure geochemical evidence of magma ocean differentiation. On the other hand, core formation is probably the most permanent, irreversible part of planetary differentiation. Hence the geochemical traces of core separation should be the most distinct remnants left behind in the mantle and crust, In the case of the Earth, core formation apparently coincided with a magma ocean that extended to a depth of approximately 1000 km. Evidence for this is found in high pressure element partitioning behavior of Ni and Co between liquid silicate and liquid iron alloy, and with the Ni-Co ratio and the abundance of Ni and Co in the Earth's upper mantle. A terrestrial magma ocean with a depth of 1000 km will solidify from the bottom up and first crystallize in the perovskite stability field. The largest effect of perovskite fractionation on major element distribution is to decrease the Si-Mg ratio in the silicate liquid and increase the Si-Mg ratio in the crystalline cumulate. Therefore, if a magma ocean with perovskite fractionation existed, then one could expect to observe an upper mantle with a lower than chondritic Si-Mg ratio. This is indeed observed in modern upper mantle peridotites. Although more experimental work is needed to fully understand the high-pressure behavior of trace element partitioning, it is likely that Hf is more compatible than Lu in perovskite-silicate liquid pairs. Thus, perovskite fractionation produces a molten mantle with a higher than chondritic Lu-Hf ratio. Arndt and Blichert-Toft measured Hf isotope compositions of Barberton komatiites that seem to require a source region with a long-lived, high Lu-Hf ratio. It is plausible that that these Barberton komatiites were generated within the majorite stability field by remelting a perovskite

  12. Small Molecule PET Tracers in Drug Discovery.

    Science.gov (United States)

    Donnelly, David J

    2017-09-01

    The process of discovering and developing a new pharmaceutical is a long, difficult, and risky process that requires numerous resources. Molecular imaging techniques such as PET have recently become a useful tool for making decisions along a drug candidate's development timeline. PET is a translational, noninvasive imaging technique that provides quantitative information about a potential drug candidate and its target at the molecular level. Using this technique provides decisional information to ensure that the right drug candidate is being chosen, for the right target, at the right dose within the right patient population. This review will focus on small molecule PET tracers and how they are used within the drug discovery process. PET provides key information about a drug candidate's pharmacokinetic and pharmacodynamic properties in both preclinical and clinical studies. PET is being used in all phases of the drug discovery and development process, and the goal of these studies are to accelerate the process in which drugs are developed. Copyright © 2017. Published by Elsevier Inc.

  13. National Biomedical Tracer Facility: Project definition study

    Energy Technology Data Exchange (ETDEWEB)

    Heaton, R.; Peterson, E. [Los Alamos National Lab., NM (United States); Smith, P. [Smith (P.A.) Concepts and Designs (United States)

    1995-05-31

    The Los Alamos National Laboratory is an ideal institution and New Mexico is an ideal location for siting the National Biomedical Tracer Facility (NBTF). The essence of the Los Alamos proposal is the development of two complementary irradiation facilities that combined with our existing radiochemical processing hot cell facilities and waste handling and disposal facilities provide a low cost alternative to other proposals that seek to satisfy the objectives of the NBTF. We propose the construction of a 30 MeV cyclotron facility at the site of the radiochemical facilities, and the construction of a 100 MeV target station at LAMPF to satisfy the requirements and objectives of the NBTF. We do not require any modifications to our existing radiochemical processing hot cell facilities or our waste treatment and disposal facilities to accomplish the objectives of the NBTF. The total capital cost for the facility defined by the project definition study is $15.2 M. This cost estimate includes $9.9 M for the cyclotron and associated facility, $2.0 M for the 100 MeV target station at LAMPF, and $3.3 M for design.

  14. TRACER STUDY OF RTU GRADUATES: AN ANALYSIS

    Directory of Open Access Journals (Sweden)

    Thelma L. Ramirez

    2014-01-01

    Full Text Available This paper aimed to determine if the field of specialization in the different colleges of RTU graduates and their academic-acquired skills and competencies are related to their present occupations. A modified Graduate Tracer Study (GTS instrument was utilized to gather the quantitative data. Out of 500 questionnaires administered, there were 250 graduates returned answered questionnaires representing the three Colleges: Education, Arts and Sciences, Business and Entrepreneurial Technology. A face to face interview was also conducted in order to support the gathered data. The SPSS was used to generate results from the acquired quantitative data using the frequency counts, percentage and the Chi-square goodness of fit test. The findings revealed that the graduates claimed that their knowledge, academic-acquired skills and competencies contributed greatly in their job performance. The Chi-square goodness of fit proved that there is a significant relationship between the graduates’ fields of specialization and their occupations after graduation. Likewise, the academic-acquired skills and competencies of the graduates are relevant to their chosen occupations. The results further proved that RTU produces marketable and appropriately trained graduates with the majority landing in course-related jobs within a short period after graduation. The study also indicates that the RTU graduates possess the skills and competencies necessary to succeed in this competitive world. However eexpansion of tie-ups with private business entities is made to at least maintain the high employability level of the graduates.

  15. USING PERFLUOROCARBON TRACERS FOR VERIFICATION OF CAP AND COVER SYSTEMS PERFORMANCE.

    Energy Technology Data Exchange (ETDEWEB)

    HEISER,J.; SULLIVAN,T.

    2001-11-01

    The Department of Energy (DOE) Environmental Management (EM) office has committed itself to an accelerated cleanup of its national facilities. The goal is to have much of the DOE legacy waste sites remediated by 2006. This includes closure of several sites (e.g., Rocky Flats and Fernald). With the increased focus on accelerated cleanup, there has been considerable concern about long-term stewardship issues in general, and verification and long-term monitoring (LTM) of caps and covers, in particular. Cap and cover systems (covers) are vital remedial options that will be extensively used in meeting these 2006 cleanup goals. Every buried waste site within the DOE complex will require some form of cover system. These covers are expected to last from 100 to 1000 years or more. The stakeholders can be expected to focus on system durability and sustained performance. DOE EM has set up a national committee of experts to develop a long-term capping (LTC) guidance document. Covers are subject to subsidence, erosion, desiccation, animal intrusion, plant root infiltration, etc., all of which will affect the overall performance of the cover. Very little is available in terms of long-term monitoring other than downstream groundwater or surface water monitoring. By its very nature, this can only indicate that failure of the cover system has already occurred and contaminants have been transported away from the site. This is unacceptable. Methods that indicate early cover failure (prior to contaminant release) or predict approaching cover failure are needed. The LTC committee has identified predictive monitoring technologies as a high priority need for DOE, both for new covers as well as existing covers. The same committee identified a Brookhaven National Laboratory (BNL) technology as one approach that may be capable of meeting the requirements for LTM. The Environmental Research and Technology Division (ERTD) at BNL developed a novel methodology for verifying and monitoring

  16. Stream Tracer Integrity: Comparative Analyses of Rhodamine-WT and Sodium Chloride through Transient Storage Modeling

    Science.gov (United States)

    Smull, E. M.; Wlostowski, A. N.; Gooseff, M. N.; Bowden, W. B.; Wollheim, W. M.

    2013-12-01

    Solute transport in natural channels describes the transport of water and dissolved matter through a river reach of interest. Conservative tracers allow us to label a parcel of stream water, such that we can track its movement downstream through space and time. A transient storage model (TSM) can be fit to the breakthrough curve (BTC) following a stream tracer experiment, as a way to quantify advection, dispersion, and transient storage processes. Arctic streams and rivers, in particular, are continuously underlain by permafrost, which provides for a simplified surface water-groundwater exchange. Sodium chloride (NaCl) and Rhodamine-WT (RWT) are widely used tracers, and differences between the two in conservative behavior and detection limits have been noted in small-scale field and laboratory studies. This study seeks to further this understanding by applying the OTIS model to NaCl and RWT BTC data from a field study on the Kuparuk River, Alaska, at varying flow rates. There are two main questions to be answered: 1) Do differences in NaCl and RWT manifest in OTIS parameter values? 2) Are the OTIS model results reliable for NaCl, RWT, or both? Fieldwork was performed in the summer of 2012 on the Kuparuk River, and modeling was performed using a modified OTIS framework, which provided for parameter optimization and further global sensitivity analyses. The results of this study will contribute to the greater body of literature surrounding Arctic stream hydrology, and it will assist in methodology for future tracer field studies. Additionally, the modeling work will provide an analysis for OTIS parameter identifiability, and assess stream tracer integrity (i.e. how well the BTC data represents the system) and its relation to TSM performance (i.e. how well the TSM can find a unique fit to the BTC data). The quantitative tools used can be applied to other solute transport studies, to better understand potential deviations in model outcome due to stream tracer choice and

  17. The Inherent Tracer Fingerprint of Captured CO2

    Science.gov (United States)

    Flude, Stephanie; Gyore, Domokos; Stuart, Finlay; Boyce, Adrian; Haszeldine, Stuart; Chalaturnyk, Rick; Gilfillan, Stuart

    2017-04-01

    Inherent tracers, the isotopic and trace gas composition of captured CO2 streams, are potentially powerful tracers for use in CCS technology [1,2]. Despite this potential, the inherent tracer fingerprint in captured CO2 streams has yet to be robustly investigated and documented [3]. Here, we will present the first high quality systematic measurements of the carbon and oxygen isotopic and noble gas fingerprints measured in anthropogenic CO2 captured from combustion power stations and fertiliser plants, using amine capture, oxyfuel and gasification processes, and derived from coal, biomass and natural gas feedstocks. We will show that δ13C values are mostly controlled by the feedstock composition, as expected. The majority of the CO2 samples exhibit δ18O values similar to atmospheric O2 although captured CO2 samples from biomass and gas feedstocks at one location in the UK are significantly higher. Our measured noble gas concentrations in captured CO2 are generally as expected [2], typically being two orders of magnitude lower in concentration than in atmospheric air. Relative noble gas elemental abundances are variable and often show an opposite trend to that of a water in contact with the atmosphere. Expected enrichments in radiogenic noble gases (4He and 40Ar) for fossil fuel derived CO2 were not always observed due to dilution with atmospheric noble gases during the CO2 generation and capture process. Many noble gas isotope ratios indicate that isotopic fractionation takes place during the CO2 generation and capture processes, resulting in isotope ratios similar to fractionated air. We conclude that phase changes associated with CO2 transport and sampling may induce noble gas elemental and isotopic fractionation, due to different noble gas solubilities between high (liquid or supercritical) and low (gaseous) density CO2. Data from the Australian CO2CRC Otway test site show that δ13C of CO2 will change once injected into the storage reservoir, but that this

  18. Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies

    Science.gov (United States)

    Templer, P.H.; Mack, M.C.; Chapin, F. S.; Christenson, L.M.; Compton, J.E.; Crook, H.D.; Currie, W.S.; Curtis, C.J.; Dail, D.B.; D'Antonio, C. M.; Emmett, B.A.; Epstein, H.E.; Goodale, C.L.; Gundersen, P.; Hobbie, S.E.; Holland, K.; Hooper, D.U.; Hungate, B.A.; Lamontagne, S.; Nadelhoffer, K.J.; Osenberg, C.W.; Perakis, S.S