BOREAS TGB-5 Dissolved Organic Carbon Data from NSA Beaver Ponds

NASA Technical Reports Server (NTRS)

Bourbonniere, Rick; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-5) team collected several data sets related to carbon and trace gas fluxes and concentrations in the Northern Study Area (NSA). This data set contains concentrations of dissolved organic and inorganic carbon species from water samples collected at various NSA sites. In particular, this set covers the NSA Tower Beaver Pond Site and the NSA Gillam Road Beaver Pond Site, including data from all visits to open water sampling locations during the BOREAS field campaigns from April to September 1994. The data are provided in tabular ASCII files.

An experimental study on the cavitation of water with dissolved gases

NASA Astrophysics Data System (ADS)

Li, Buxuan; Gu, Youwei; Chen, Min

2017-12-01

Cavitation inception is generally determined by the tensile strengths of liquids. Investigations on the tensile strength of water, which is essential in many fields, will help understand the promotion/prevention of cavitation and related applications in water. Previous experimental studies, however, vary in their conclusions about the value of tensile strength of water; the difference is commonly attributed to the existence of impurities in water. Dissolved gases, especially oxygen and nitrogen from the air, are one of the most common kinds of impurities in water. The influence of these gases on the tensile strength of water is still unclear. This study investigated the effects of dissolved gases on water cavitation through experiments. Cavitation in water is generated by acoustic method. Water samples are prepared with dissolved oxygen and nitrogen in different gas concentrations. Results show that under the same temperature, the tensile strength of water with dissolved oxygen or nitrogen decreases with increased gas concentration compared with that of ultrapure water. Under the same gas concentration and temperature, water with dissolved oxygen shows a lower tensile strength than that with dissolved nitrogen. Possible reasons of these results are also discussed.

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

PubMed Central

Heshka, Nicole E.; Hager, Darcy B.

2015-01-01

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate interferences, a two dimensional column configuration is used, with a Deans switch employed to transfer hydrogen sulfide from the first to the second column (heart-cutting). Liquid crude samples are first separated on a dimethylpolysiloxane column, and light gases are heart-cut and further separated on a bonded porous layer open tubular (PLOT) column that is able to separate hydrogen sulfide from other light sulfur species. Hydrogen sulfide is then detected with a sulfur chemiluminescence detector, adding an additional layer of selectivity. Following separation and detection of hydrogen sulfide, the system is backflushed to remove the high-boiling hydrocarbons present in the crude samples and to preserve chromatographic integrity. Dissolved hydrogen sulfide has been quantified in liquid samples from 1.1 to 500 ppm, demonstrating wide applicability to a range of samples. The method has also been successfully applied for the analysis of gas samples from crude oil headspace and process gas bags, with measurement from 0.7 to 9,700 ppm hydrogen sulfide. PMID:26709594

Using dissolved gas analysis to investigate the performance of an organic carbon permeable reactive barrier for the treatment of mine drainage

USGS Publications Warehouse

Williams, R.L.; Mayer, K.U.; Amos, R.T.; Blowes, D.W.; Ptacek, C.J.; Bain, J.G.

2007-01-01

The strongly reducing nature of permeable reactive barrier (PRB) treatment materials can lead to gas production, potentially resulting in the formation of gas bubbles and ebullition. Degassing in organic C based PRB systems due to the production of gases (primarily CO2 and CH4) is investigated using the depletion of naturally occurring non-reactive gases Ar and N2, to identify, confirm, and quantify chemical and physical processes. Sampling and analysis of dissolved gases were performed at the Nickel Rim Mine Organic Carbon PRB, which was designed for the treatment of groundwater contaminated by low quality mine drainage characterized by slightly acidic pH, and elevated Fe(II) and SO4 concentrations. A simple 4-gas degassing model was used to analyze the dissolved gas data, and the results indicate that SO4 reduction is by far the dominant process of organic C consumption within the barrier. The data provided additional information to delineate rates of microbially mediated SO4 reduction and confirm the presence of slow and fast flow zones within the barrier. Degassing was incorporated into multicomponent reactive transport simulations for the barrier and the simulations were successful in reproducing observed dissolved gas trends.

Methane occurrence in groundwater of south-central New York State, 2012: summary of findings

USGS Publications Warehouse

Heisig, Paul M.; Scott, Tia-Marie

2013-01-01

A survey of methane in groundwater was undertaken to document methane occurrence on the basis of hydrogeologic setting within a glaciated 1,810-square-mile area of south-central New York that has not seen shale-gas resource development. The adjacent region in northeastern Pennsylvania has undergone shale-gas resource development from the Marcellus Shale. Well construction and subsurface data were required for each well sampled so that the local hydrogeologic setting could be classified. All wells were also at least 1 mile from any known gas well (active, exploratory, or abandoned). Sixty-six domestic wells and similar purposed supply wells were sampled during summer 2012. Field water-quality characteristics (pH, specific conductance, dissolved oxygen, and temperature) were measured at each well, and samples were collected and analyzed for dissolved gases, including methane and short-chain hydrocarbons. Carbon and hydrogen isotopic ratios of methane were measured in 21 samples that had at least 0.3 milligram per liter (mg/L) methane.

Effect of high carbon dioxide atmosphere packaging and soluble gas stabilization pre-treatment on the shelf-life and quality of chicken drumsticks.

PubMed

Al-Nehlawi, A; Saldo, J; Vega, L F; Guri, S

2013-05-01

The effects of an aerobic modified atmosphere packaging (MAP) (70% CO2, 15% O2 and 15% N2) with and without a CO2 3-h soluble gas stabilization (SGS) pre-treatment of chicken drumsticks were determined for various package and product quality characteristics. The CO2 dissolved into drumsticks was determined. The equilibrium between CO2 dissolved in drumsticks and CO2 in head space was reached within 48h after packaging, showing highest values of CO2 in SGS pre-treated samples. This greater availability of CO2 resulted in lower counts of TAB and Pseudomonas in SGS than in MAP drumsticks. Package collapse was significantly reduced in SGS samples. The average of CO2 dissolved in the MAP treatment was 567mg CO2kg(-1) of chicken and, 361mg CO2kg(-1) of chicken during the MAP treatment, in SGS pre-treated samples. This difference could be the quantity of CO2 dissolved during SGS pre-treatment. These results highlight the advantages of using SGS versus traditional MAP for chicken products preservation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Environmental legacy of an underground gas well blowout: long-term effects of gas and brine leakage on groundwater quality

NASA Astrophysics Data System (ADS)

Schout, Gilian; Hartog, Niels; Majid Hassanizadeh, S.; Griffioen, Jasper

2017-04-01

In 1965, a catastrophic underground blowout occurred during the drilling of a gas well in the village of Sleen, the Netherlands. The blowout led to the uncontrolled release of large amounts of natural gas and saline groundwater. Now, 50 years later, a number of nearby groundwater monitoring have been sampled to study the long term effects of this event on the groundwater composition of the overlying freshwater aquifers. The findings are used as an analogue for studying the potential adverse effects of hydraulic fracturing on groundwater quality. In total, 27 samples were taken and analysed for dissolved gas molecular and isotopic composition, major ion chemistry, water isotopes and stable chlorine isotope ratios. The resulting data show that concentrations of dissolved methane are still strongly elevated compared to background samples in a plume downstream of the blowout location. Isotopic data reveals the thermogenic nature of this plume; all samples with methane concentrations greater than 10 mg/l (n=12) had δC-CH4 values greater than -30‰ (VPDB), characteristic of thermogenic methane. The maximum distance at which thermogenic methane is observed is at approximately 500 meter downstream of the centre of the blowout. The progressive enrichment of both δ13C-CH4 and δ2D-CH4, that is observed with distance from the well and decreasing methane concentrations, presents strong evidence for the role of anaerobic methane oxidation (AOM) in limiting the spread of the dissolved methane plume. Low sulphate and increased Fe(II) and Mn(II) concentrations indeed suggest that multiple AOM pathways are involved in the natural attenuation of the dissolved methane plume. Chlorine concentrations were only elevated in a subset of wells in close proximity to the blowout location, indicating that the present-day effects of brine migration are minimal. Nevertheless, elevated Na/Cl ratio's in multiple wells reveal that freshening of the aquifer is still on-going. In summary, this research sheds new light on the long-term effects of natural gas and brine leakage on groundwater quality, which is considered one of the main environmental hazards related to hydraulic fracturing and unconventional gas production in general. Notably, it shows that the anaerobic oxidation of methane may play a major role in containing the effects of uncontrolled gas migration from reservoirs to shallow aquifers.

Methane from shallow seep areas of the NW Svalbard Arctic margin does not reach the sea surface

NASA Astrophysics Data System (ADS)

Silyakova, Anna; Greinert, Jens; Jansson, Pär; Ferré, Bénédicte

2015-04-01

Methane, an important greenhouse gas, leaks from large areas of the Arctic Ocean floor. One overall question is how much methane passes from the seabed through the water column, potentially reaching the atmosphere. Transport of methane from the ocean floor into and through the water column depends on many factors such as distribution of gas seeps, microbial methane oxidation, and ambient oceanographic conditions, which may trigger a change in seep activity. From June-July 2014 we investigated dissolved methane in the water column emanating from the "Prins Karls Forland seeps" area offshore the NW Svalbard Arctic margin. Measurements of the spatial variability of dissolved methane in the water column included 65 CTD stations located in a grid covering an area of 30 by 15 km. We repeated an oceanographic transect twice in a week for time lapse studies, thus documenting significant temporal variability in dissolved methane above one shallow seep site (~100 m water depth). Analysis of both nutrient concentrations and dissolved methane in water samples from the same transect, reveal striking similarities in spatial patterns of both dissolved methane and nutrients indicating that microbial community is involved in methane cycling above the gas seepage. Our preliminary results suggest that although methane release can increase in a week's time, providing twice as much dissolved gas to the water column, no methane from a seep reaches the sea surface. Instead it spreads horizontally under the pycnocline. Yet microbial communities react rapidly to the methane supply above gas seepage areas and may also have an important role as an effective filter, hindering methane release from the ocean to the atmosphere during rapid methane ebullition. This study is funded by CAGE (Centre for Arctic Gas Hydrate, Environment and Climate), Norwegian Research Council grant no. 223259.

Optimization of the solvent-based dissolution method to sample volatile organic compound vapors for compound-specific isotope analysis.

PubMed

Bouchard, Daniel; Wanner, Philipp; Luo, Hong; McLoughlin, Patrick W; Henderson, James K; Pirkle, Robert J; Hunkeler, Daniel

2017-10-20

The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant. Among solvents tested, tetraethylene glycol dimethyl ether (TGDE) showed the best aptitude for the method. TGDE has a great affinity with TCE and benzene, hence efficiently dissolving the compounds during their transition through the solvent. The method detection limit for TCE (5±1μg/m 3 ) and benzene (1.7±0.5μg/m 3 ) is lower when using TGDE compared to methanol, which was previously used (385μg/m 3 for TCE and 130μg/m 3 for benzene) [2]. The method detection limit refers to the minimal gas phase concentration in ambient air required to load sufficient VOC mass into TGDE to perform δ 13 C analysis. Due to a different analytical procedure, the method detection limit associated with δ 37 Cl analysis was found to be 156±6μg/m 3 for TCE. Furthermore, the experimental results validated the relationship between the gas phase TCE and the progressive accumulation of dissolved TCE in the solvent during the sampling process. Accordingly, based on the air-solvent partitioning coefficient, the sampling methodology (e.g. sampling rate, sampling duration, amount of solvent) and the final TCE concentration in the solvent, the concentration of TCE in the gas phase prevailing during the sampling event can be determined. Moreover, the possibility to analyse for TCE concentration in the solvent after sampling (or other targeted VOCs) allows the field deployment of the sampling method without the need to determine the initial gas phase TCE concentration. The simplified field deployment approach of the solvent-based dissolution method combined with the conventional analytical procedure used for groundwater samples substantially facilitates the application of CSIA to gas phase studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimating gas exchange of CO2 and CH4 between headwater systems and the atmosphere in Southwest Sweden

NASA Astrophysics Data System (ADS)

Somlai, Celia; Natchimuthu, Sivakiruthika; Bastviken, David; Lorke, Andreas

2015-04-01

Quantifying the role of inland water systems in terms of carbon sinks and sources and their connection to the terrestrial ecosystems and landscapes is fundamental for improving the balance approach of regional and global carbon budgets. Recent research showed that freshwater bodies emit significant amounts of CO2 and CH4 into the atmosphere. The extent of the emissions from small streams and headwaters, however, remains uncertain due to a limited availability of data. Studies have shown that headwater systems receive most of the terrestrial organic carbon, have the highest dissolved CO2 concentration and the highest gas exchange velocities and cover the largest fractional surface area within fluvial networks. The gas exchange between inland waters and the atmosphere is controlled by two factors: the difference between the dissolved gas concentration and its atmospheric equilibrium concentration, and the gas exchange velocity. The direct measurement of the dissolved gas concentration of greenhouse gases can be measured straightforwardly, for example, by gas chromatography from headspace extraction of water sample. In contrast, direct measurement of gas exchange velocity is more complex and time consuming, as simultaneous measurements with a volatile and nonvolatile inert tracer gas are needed. Here we analyze measurements of gas exchange velocities, concentrations and fluxes of dissolved CO2 and CH4, as well as loads of total organic and inorganic carbon in 10 reaches in headwater streams in Southwest Sweden. We compare the gas exchange velocities measured directly through tracer injections with those estimated through various empirical approaches, which are based on modelled and measured current velocity, stream depth and slope. Furthermore, we estimate the resulting uncertainties of the flux estimates. We also present different time series of dissolved CO2, CH4 and O2 concentration, water temperature, barometric pressure, electro conductivity, and pH values measured during the period of tracer injection.

Innovations in Sampling Pore Fluids From Deep-Sea Hydrate Sites

NASA Astrophysics Data System (ADS)

Lapham, L. L.; Chanton, J. P.; Martens, C. S.; Schaefer, H.; Chapman, N. R.; Pohlman, J. W.

2003-12-01

We have developed a sea-floor probe capable of collecting and returning undecompressed pore water samples at in situ pressures for determination of dissolved gas concentrations and isotopic values in deep-sea sediments. In the summer of 2003, we tested this instrument in sediments containing gas hydrates off Vancouver Island, Cascadia Margin from ROPOS (a remotely operated vehicle) and in the Gulf of Mexico from Johnson-Sea-Link I (a manned submersible). Sediment push cores were collected alongside the probe to compare methane concentrations and stable carbon isotope compositions in decompressed samples vs. in situ samples obtained by probe. When sufficient gas was available, ethane and propane concentrations and isotopes were also compared. Preliminary data show maximum concentrations of dissolved methane to be 5mM at the Cascadia Margin Fish Boat site (850m water depth) and 12mM in the Gulf of Mexico Bush Hill hydrate site (550m water depth). Methane concentrations were, on average, five times as high in probe samples as in the cores. Carbon isotopic values show a thermogenic input and oxidative effects approaching the sediment-water interface at both sites. This novel data set will provide information that is critical to the understanding of the in situ processes and environmental conditions controlling gas hydrate occurrences in sediments.

A simple device for the collection of water and dissolved gases at defined depths

USDA-ARS?s Scientific Manuscript database

A device, consisting of a jar fitted with an inlet comprised of a gas-tight check valve and 2-way ball valve outlet connected via tubing to a portable peristaltic pump, was constructed to collect water samples without atmospheric contamination or loss of dissolved gases. A headspace void for dissol...

Determination of dissolved-phase pesticides in surface water from the Yakima River basin, Washington, using the Goulden large-sample extractor and gas chromatography/mass spectrometer

USGS Publications Warehouse

Foster, Gregory D.; Gates, Paul M.; Foreman, William T.; McKenzie, Stuart W.; Rinella, Frank A.

1993-01-01

Concentrations of pesticides in the dissolved phase of surface water samples from the Yakima River basin, WA, were determined using preconcentration in the Goulden large-sample extractor (GLSE) and gas chromatography/mass spectrometry (GC/MS) analysis. Sample volumes ranging from 10 to 120 L were processed with the GLSE, and the results from the large-sample analyses were compared to those derived from 1-L continuous liquid-liquid extractions Few of the 40 target pesticides were detected in 1-L samples, whereas large-sample preconcentration in the GLSE provided detectable levels for many of the target pesticides. The number of pesticides detected in GLSE processed samples was usually directly proportional to sample volume, although the measured concentrations of the pesticides were generally lower at the larger sample volumes for the same water source. The GLSE can be used to provide lower detection levels relative to conventional liquid-liquid extraction in GC/MS analysis of pesticides in samples of surface water.

Sources and migration pathways of natural gas in near-surface ground water beneath the Animas River valley, Colorado and New Mexico

USGS Publications Warehouse

Chafin, Daniel T.

1994-01-01

In July 1990, the U.S. Geological Survey began a study of the occurrence of natural gas in near-surface ground water in the Animas River valley in the San Juan Basin between Durango, Colorado, and Aztec, New Mexico. The general purpose of the study was to identify the sources and migration pathways of natural gas in nearsurface ground water in the study area. The purpose of this report is to present interpretive conclusions for the study, primarily based on data collected by the U.S. Geological Survey from August 1990 to May 1991.Seventy of the 205 (34 percent) groundwater samples collected during August-November 1990 had methane concentrations that exceeded the reporting limit of 0.005 milligram per liter. The maximum concentration was 39 milligrams per liter, and the mean concentration was 1.3 milligrams per liter. Samples from wells completed in bedrock have greater mean concentrations of methane than samples from wells completed in alluvium. Correlations indicate weak or nonexistent associations between dissolved-methane concentrations and concentrations of dissolved solids, major ions, bromide, silica, iron, manganese, and carbon dioxide. Dissolved methane was associated with hydrogen sulfide.Soil-gas-methane concentrations were measurable at few of 192 ground-water sites, even at sites at which ground water contained large concentrations of dissolved methane, which indicates that soil-gas surveys are not useful to delineate areas of gas-affected ground water. The reporting limit of 0.005 milligram per liter of gas was equaled or exceeded by 40 percent of soil-gas measurements adjacent to 352 gas-well casings. Concentrations of at least 100 milligrams per liter of gas were measured at 25 (7 percent) of the sites.Potential sources of gases in water, soil, gas-well surface casings, and cathodic-protection wells were determined on the basis of their isotopic and molecular compositions and available information about gas-well construction or leaks. Biogenic and thermogenic sources of gas exist in the near-surface environment of the study area. Biogenic gas is present locally in the near-surface Animas and Nacimiento formations, and biogenic gas has been detected in water wells completed in those rocks. Most gas probably is thermogenic gas from deep reservoirs, including the Dakota Sandstone, Mesaverde Group, Lewis Shale, Pictured Cliffs Sandstone, and coals in the Fruitland Formation. Less important sources include sandstones in the upper Fruitland Formation and the Kirtland Shale.Although migration of gas by diffusion or through natural fractures is possible, manmade conduits probably account for most of the upward migration of gas to the near-surface environment of the study area. Primary migration pathways largely consist of 1) leaking, conventional gas wells and 2) uncemented annuli of conventional gas wells along coals in the Fruitland Formation. Secondary migration pathways are gas-well annuli, cathodic-protection wells, seismic-test holes, and bedrock water wells.

Greenhouse gases dissolved in soil solution - often ignored, but important?

NASA Astrophysics Data System (ADS)

Weymann, Daniel; Brueggemann, Nicolas; Puetz, Thomas; Vereecken, Harry

2014-05-01

Flux measurements of climate-relevant trace gases from soils are frequently undertaken in contemporary ecosystem studies and substantially contribute to our understanding of greenhouse gas balances of the biosphere. While the great majority of such investigations builds on closed chamber and eddy covariance measurements, where upward gas fluxes to the atmosphere are measured, fewest concurrently consider greenhouse gas dissolution in the seepage and leaching of dissolved gases via the vadose zone to the groundwater. Here we present annual leaching losses of dissolved N2O and CO2 from arable, grassland, and forest lysimeter soils from three sites differing in altitude and climate. We aim to assess their importance in comparison to direct N2O emission, soil respiration, and further leaching parameters of the C- and N cycle. The lysimeters are part of the Germany-wide lysimeter network initiative TERENO-SoilCan, which investigates feedbacks of climate change to the pedosphere on a long-term scale. Soil water samples were collected weekly from different depths of the profiles by means of suction cups. A laboratory pre-experiment proved that no degassing occurred under those sampling conditions. We applied the headspace equilibration technique to determine dissolved gas concentrations by gas chromatography. The seepage water of all lysimeters was consistently supersaturated with N2O and CO2 compared to water equilibrated ambient air. In terms of N2O, leaching losses increased in the ascending order forest, grassland, and arable soils, respectively. In case of the latter soils, we observed a strong variability of N2O, with dissolved concentrations up to 23 μg N L-1. However, since seepage discharge of the arable lysimeters was comparatively small and mostly limited to the hydrological winter season, leached N2O appeared to be less important than direct N2O emissions. In terms of dissolved CO2,our measurements revealed considerable leaching losses from the mountainous forest and grassland soils, based on concentrations up to 24 mg C L-1 and high seepage discharge. Such losses turned out to be similarly important like soil respiration, particularly during winter when temperature-dependent soil respiration declined. In conclusion, the results of the first year of our measurements provide evidence that dissolved greenhouse gases should be considered in studies which aim to assess full greenhouse gas balances, particularly in ecosystems where hydrological conditions favour microbial activity and high leaching losses.

Data from exploratory sampling of groundwater in selected oil and gas areas of coastal Los Angeles County and Kern and Kings Counties in southern San Joaquin Valley, 2014–15: California oil, gas, and groundwater project

USGS Publications Warehouse

Dillon, David B.; Davis, Tracy A.; Landon, Matthew K.; Land, Michael T.; Wright, Michael T.; Kulongoski, Justin T.

2016-12-09

Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey from September 2014 through January 2015 as part of the California State Water Resources Control Board’s Water Quality in Areas of Oil and Gas Production Regional Groundwater Monitoring Program. The Regional Groundwater Monitoring Program was established in response to the California Senate Bill 4 of 2013 mandating that the California State Water Resources Control Board design and implement a groundwater-monitoring program to assess potential effects of well-stimulation treatments on groundwater resources in California. The U.S. Geological Survey is in cooperation with the California State Water Resources Control Board to collaboratively implement the Regional Groundwater Monitoring Program through the California Oil, Gas, and Groundwater Project. Many researchers have documented the utility of different suites of chemical tracers for evaluating the effects of oil and gas development on groundwater quality. The purpose of this exploratory sampling effort was to determine whether tracers reported in the literature could be used effectively in California. This reconnaissance effort was not designed to assess the effects of oil and gas on groundwater quality in the sampled areas. A suite of water-quality indicators and geochemical tracers were sampled at groundwater sites in selected areas that have extensive oil and gas development. Groundwater samples were collected from a total of 51 wells, including 37 monitoring wells at 17 multiple-well monitoring sites in coastal Los Angeles County and 5 monitoring wells and 9 water-production wells in southern San Joaquin Valley, primarily in Kern and Kings Counties. Groundwater samples were analyzed for field waterquality indicators; organic constituents, including volatile and semi-volatile organic compounds and dissolved organic carbon indicators; naturally present inorganic constituents, including trace elements, nutrients, major and minor ions, and iron species; naturally present stable and radioactive isotopes; dissolved noble gases; dissolved standard and hydrocarbon gases, δ13C of methane, ethane, and δ2 H of methane. In total, 249 constituents and water-quality indicators were measured. Four types of quality-control samples (blanks, replicates, matrix spikes, and surrogates spiked in environmental and blank samples) were collected at approximately 10 percent of the wells. The quality-control data were used to determine whether the groundwater-sample data were of sufficient quality for the measured analytes to be used as potential indicators of oil and gas effects. The data from the 51 groundwater samples and from the quality-control samples are presented in this report.

Preparation of water samples for carbon-14 dating

USGS Publications Warehouse

Feltz, H.R.; Hanshaw, Bruce B.

1963-01-01

For most natural water, a large sample is required to provide the 3 grams of carbon needed for a carbon-14 determination. A field procedure for isolating total dissolved-carbonate species is described. Carbon dioxide gas is evolved by adding sulfuric acid to the water sample; the gas is then collected in a sodium hydroxide trap by recycling in a closed system. The trap is then transported to the dating laboratory where the carbon-14 is counted.

High-pressure liquid chromatography with direct injection of gas sample.

PubMed

Astanin, Anton I; Baram, Grigory I

2017-06-09

The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples. Samples were injected into the column in two ways: a) through the valve without a flow stop; b) after stopping the flow and relieving all pressure. We showed that an injectable gas volume could reach 70% of column dead volume. When an injected gaseous sample volume was less than 10% of the column dead volume, the resulting peaks were symmetrical and the column efficiency was high. Copyright © 2017 Elsevier B.V. All rights reserved.

Springs, streams, and gas vent on and near Mount Adams volcano, Washington

USGS Publications Warehouse

Nathenson, Manuel; Mariner, Robert H.

2013-01-01

Springs and some streams on Mount Adams volcano have been sampled for chemistry and light stable isotopes of water. Spring temperatures are generally cooler than air temperatures from weather stations at the same elevation. Spring chemistry generally reflects weathering of volcanic rock from dissolved carbon dioxide. Water in some springs and streams has either dissolved hydrothermal minerals or has reacted with them to add sulfate to the water. Some samples appear to have obtained their sulfate from dissolution of gypsum while some probably involve reaction with sulfide minerals such as pyrite. Light stable isotope data for water from springs follow a local meteoric water line, and the variation of isotopes with elevation indicate that some springs have very local recharge and others have water from elevations a few hundred meters higher. No evidence was found for thermal or slightly thermal springs on Mount Adams. A sample from a seeping gas vent on Mount Adams was at ambient temperature, but the gas is similar to that found on other Cascade volcanoes. Helium isotopes are 4.4 times the value in air, indicating that there is a significant component of mantle helium. The lack of fumaroles on Mount Adams and the ambient temperature of the gas indicates that the gas is from a hydrothermal system that is no longer active.

Summary and Preliminary Interpretation of Tritium and Dissolved Noble Gas Data from Site 300

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

Visser, A.; Singleton, M.; Madrid, V.

2014-01-29

In October 2013, groundwater samples were collected from 10 wells from Site 300 and analyzed by the Environmental Radiochemistry Laboratory at Lawrence Livermore National Laboratory (LLNL). Groundwater samples were analyzed for groundwater age tracers: tritium, the helium isotope ratio of dissolved helium and the concentrations of dissolved noble gases (Helium, Neon, Argon, Krypton, and Xenon). A subset of the samples was also analyzed for excess nitrogen due to saturated zone denitrification. The age-dating data were used to evaluate the degree to which groundwater at a particular monitoring well was derived from pre-modern and/or modern sources. More specifically, the analyses canmore » be used to determine whether the recharge age of the groundwater beneath the site pre-dates anthropogenic activities at the site.« less

A simple headspace equilibration method for measuring dissolved methane

USGS Publications Warehouse

Magen, C; Lapham, L.L.; Pohlman, John W.; Marshall, Kristin N.; Bosman, S.; Casso, Michael; Chanton, J.P.

2014-01-01

Dissolved methane concentrations in the ocean are close to equilibrium with the atmosphere. Because methane is only sparingly soluble in seawater, measuring it without contamination is challenging for samples collected and processed in the presence of air. Several methods for analyzing dissolved methane are described in the literature, yet none has conducted a thorough assessment of the method yield, contamination issues during collection, transport and storage, and the effect of temperature changes and preservative. Previous extraction methods transfer methane from water to gas by either a "sparge and trap" or a "headspace equilibration" technique. The gas is then analyzed for methane by gas chromatography. Here, we revisit the headspace equilibration technique and describe a simple, inexpensive, and reliable method to measure methane in fresh and seawater, regardless of concentration. Within the range of concentrations typically found in surface seawaters (2-1000 nmol L-1), the yield of the method nears 100% of what is expected from solubility calculation following the addition of known amount of methane. In addition to being sensitive (detection limit of 0.1 ppmv, or 0.74 nmol L-1), this method requires less than 10 min per sample, and does not use highly toxic chemicals. It can be conducted with minimum materials and does not require the use of a gas chromatograph at the collection site. It can therefore be used in various remote working environments and conditions.

Dissolved methane occurrences in aquifers in the footprint of Texas shale plays and their controls

NASA Astrophysics Data System (ADS)

Nicot, J. P.; Mickler, P. J.; Larson, T.; Darvari, R.; Smyth, R. C.

2015-12-01

Many constituents typically associated with oil and gas production, such as methane and higher-order hydrocarbons, exist naturally in shallow groundwater. Recent studies of aquifers in the footprint of several gas plays across the US have showed that (1) dissolved thermogenic methane may or may not be present in the shallow subsurface and (2) shallow thermogenic methane could be naturally occurring and emplaced through mostly vertical migration over geologic time and is not necessarily a consequence of gas production from a gas play. A total of 800+ water wells have been sampled across the state of Texas to characterize shallow methane in fresh-water aquifers overlying shale plays and other tight formations (Barnett, Eagle Ford, Haynesville shale areas as well as in the Delaware Basin of West Texas). Analytical results suggest that dissolved methane is not widespread in shallow groundwater and that, when present at concentration greater than 10 mg/L, is often of natural but thermogenic or mixed origin according to the isotopic signature and to the presence of other light hydrocarbons.

Methane concentrations in water wells unrelated to proximity to existing oil and gas wells in northeastern Pennsylvania.

PubMed

Siegel, Donald I; Azzolina, Nicholas A; Smith, Bert J; Perry, A Elizabeth; Bothun, Rikka L

2015-04-07

Recent studies in northeastern Pennsylvania report higher concentrations of dissolved methane in domestic water wells associated with proximity to nearby gas-producing wells [ Osborn et al. Proc. Natl. Acad. Sci. U. S. A. 2011 , 108 , 8172 ] and [ Jackson et al. Proc. Natl. Acad. Sci. U. S. A. , 2013 , 110 , 11250 ]. We test this possible association by using Chesapeake Energy's baseline data set of over 11,300 dissolved methane analyses from domestic water wells, densely arrayed in Bradford and nearby counties (Pennsylvania), and near 661 pre-existing oil and gas wells. The majority of these, 92%, were unconventional wells, drilled with horizontal legs and hydraulically fractured. Our data set is hundreds of times larger than data sets used in prior studies. In contrast to prior findings, we found no statistically significant relationship between dissolved methane concentrations in groundwater from domestic water wells and proximity to pre-existing oil or gas wells. Previous analyses used small sample sets compared to the population of domestic wells available, which may explain the difference in prior findings compared to ours.

The effect of dissolve gas concentration in the initial growth stage of multi cavitation bubbles. Differences between vacuum degassing and ultrasound degassing.

PubMed

Yanagida, Hirotaka

2008-04-01

The sonochemical luminescence intensity from luminol was measured at a sampling rate of several kilohertz. This was noted at three different periods: first, the latent period in which no light emission occurs at all; second, the increased emission period from the start of light emission to the time when a steady state is reached; and third, the steady state period in which light emission occurs at the steady state value. When irradiated with ultrasound of different intensities, the times of the latent period and increased emission period are shorter for higher ultrasound intensities. To know how the dissolved oxygen content is involved in early-stage cavitation growth, an experiment was conducted using solutions with varying dissolved oxygen contents from 100% to 37%. For dissolved air content of 50% or less, it was found that the latent period was 30 times longer in a saturated condition. It was also found that the increased emission period was 10 times longer. However, the emission intensity in the steady state did not change at all even when the initial dissolved gas concentration of the sample was changed. From this, it was found that the reuse of collapsed bubbles takes place efficiently in the steady state. Dissolved oxygen was reduced by the use of a vacuum pump and by the degassing action of ultrasound, and it was discovered that the behavior of transient emission differed for the two ways of degassing.

Hyperpolarized xenon NMR and MRI signal amplification by gas extraction

PubMed Central

Zhou, Xin; Graziani, Dominic; Pines, Alexander

2009-01-01

A method is reported for enhancing the sensitivity of NMR of dissolved xenon by detecting the signal after extraction to the gas phase. We demonstrate hyperpolarized xenon signal amplification by gas extraction (Hyper-SAGE) in both NMR spectra and magnetic resonance images with time-of-flight information. Hyper-SAGE takes advantage of a change in physical phase to increase the density of polarized gas in the detection coil. At equilibrium, the concentration of gas-phase xenon is ≈10 times higher than that of the dissolved-phase gas. After extraction the xenon density can be further increased by several orders of magnitude by compression and/or liquefaction. Additionally, being a remote detection technique, the Hyper-SAGE effect is further enhanced in situations where the sample of interest would occupy only a small proportion of the traditional NMR receiver. Coupled with targeted xenon biosensors, Hyper-SAGE offers another path to highly sensitive molecular imaging of specific cell markers by detection of exhaled xenon gas. PMID:19805177

Matrix effects in inductively coupled plasma mass spectrometry

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

Chen, Xiaoshan

1995-07-07

The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the "Fassel" TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS,more » the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.« less

Dating base flow in streams using dissolved gases and diurnal temperature changes

USGS Publications Warehouse

Sanford, Ward E.; Casile, Gerolamo C.; Haase, Karl B.

2015-01-01

A method is presented for using dissolved CFCs or SF6 to estimate the apparent age of stream base flow by indirectly estimating the mean concentration of the tracer in the inflowing groundwater. The mean value is estimated simultaneously with the mean residence times of the gas and water in the stream by sampling the stream for one or both age tracers, along with dissolved nitrogen and argon at a single location over a period of approximately 12–14 h. The data are fitted to an equation representing the temporal in-stream gas exchange as it responds to the diurnal temperature fluctuation. The efficacy of the method is demonstrated by collecting and analyzing samples at six different stream locations across parts of northern Virginia, USA. The studied streams drain watersheds with areas of between 2 and 122 km2 during periods when the diurnal stream temperature ranged between 2 and 5°C. The method has the advantage of estimating the mean groundwater residence time of discharge from the watershed to the stream without the need for the collection of groundwater infiltrating to streambeds or local groundwater sampled from shallow observation wells near the stream.

Methane Occurrences in Aquifers Overlying the Barnett Shale Play with a Focus on Parker County, Texas.

PubMed

Nicot, Jean-Philippe; Mickler, Patrick; Larson, Toti; Clara Castro, M; Darvari, Roxana; Uhlman, Kristine; Costley, Ruth

2017-07-01

Clusters of elevated methane concentrations in aquifers overlying the Barnett Shale play have been the focus of recent national attention as they relate to impacts of hydraulic fracturing. The objective of this study was to assess the spatial extent of high dissolved methane previously observed on the western edge of the play (Parker County) and to evaluate its most likely source. A total of 509 well water samples from 12 counties (14,500 km 2 ) were analyzed for methane, major ions, and carbon isotopes. Most samples were collected from the regional Trinity Aquifer and show only low levels of dissolved methane (85% of 457 unique locations <0.1 mg/L). Methane, when present is primarily thermogenic (δ 13 C 10th and 90th percentiles of -57.54 and -39.00‰ and C1/C2+C3 ratio 10th, 50th, and 90th percentiles of 5, 15, and 42). High methane concentrations (>20 mg/L) are limited to a few spatial clusters. The Parker County cluster area includes historical vertical oil and gas wells producing from relatively shallow formations and recent horizontal wells producing from the Barnett Shale (depth of ∼1500 m). Lack of correlation with distance to Barnett Shale horizontal wells, with distance to conventional wells, and with well density suggests a natural origin of the dissolved methane. Known commercial very shallow gas accumulations (<200 m in places) and historical instances of water wells reaching gas pockets point to the underlying Strawn Group of Paleozoic age as the main natural source of the dissolved gas. © 2017, National Ground Water Association.

Online dissolved methane and total dissolved sulfide measurement in sewers.

PubMed

Liu, Yiwen; Sharma, Keshab R; Fluggen, Markus; O'Halloran, Kelly; Murthy, Sudhir; Yuan, Zhiguo

2015-01-01

Recent studies using short-term manual sampling of sewage followed by off-line laboratory gas chromatography (GC) measurement have shown that a substantial amount of dissolved methane is produced in sewer systems. However, only limited data has been acquired to date due to the low frequency and short span of this method, which cannot capture the dynamic variations of in-sewer dissolved methane concentrations. In this study, a newly developed online measuring device was used to monitor dissolved methane concentrations at the end of a rising main sewer network, over two periods of three weeks each, in summer and early winter, respectively. This device uses an online gas-phase methane sensor to measure methane under equilibrium conditions after being stripped from the sewage. The data are then converted to liquid-phase methane concentrations according to Henry's Law. The detection limit and range are suitable for sewer application and can be adjusted by varying the ratio of liquid-to-gas phase volume settings. The measurement presented good linearity (R² > 0.95) during field application, when compared to off-line measurements. The overall data set showed a wide variation in dissolved methane concentration of 5-15 mg/L in summer and 3.5-12 mg/L in winter, resulting in a significant average daily production of 24.6 and 19.0 kg-CH₄/d, respectively, from the network with a daily average sewage flow of 2840 m³/day. The dissolved methane concentration demonstrated a clear diurnal pattern coinciding with flow and sulfide fluctuation, implying a relationship with the wastewater hydraulic retention time (HRT). The total dissolved sulfide (TDS) concentration in sewers can be determined simultaneously with the same principle.

Ancient dissolved methane in inland waters at low concentrations revealed by a new collection method for radiocarbon (^{14}C) analysis

NASA Astrophysics Data System (ADS)

Dean, Joshua F.; Billett, Michael F.; Murray, Callum; Garnett, Mark H.

2017-04-01

Methane (CH4) is a powerful greenhouse gas and is released to the atmosphere from freshwater systems in numerous biomes globally. Radiocarbon (14C) analysis of methane can provide unique information about its age, source and rate of cycling in natural environments. Methane is often released from aquatic sediments in bubbles (ebullition), but dissolved methane is also present in lakes and streams at lower concentrations, and may not be of the same age or source. Obtaining sufficient non-ebullitive aquatic methane for 14C analysis remains a major technical challenge. Previous studies have shown that freshwater methane, in both dissolved and ebullitive form, can be significantly older than other forms of aquatic carbon (C), and it is therefore important to characterise this part of the terrestrial C balance. We present a novel method to capture sufficient amounts of dissolved methane from freshwater environments for 14C analysis by circulating water across a hydrophobic, gas-permeable membrane and collecting the methane in a large collapsible vessel. The results of laboratory and field tests show that reliable dissolved δ13CH4 and 14CH4 samples can be readily collected over short time periods (˜4 to 24 hours), at relatively low cost and from a variety of surface water types. The initial results further support previous findings that dissolved methane can be significantly older than other forms of aquatic C, especially in organic-rich catchments, and is currently unaccounted for in many terrestrial C balances and models. This method is suitable for use in remote locations, and could potentially be used to detect the leakage of unique 14CH4 signatures from point sources into waterways, e.g. coal seam gas and landfill gas.

Rapid analysis of dissolved methane, ethylene, acetylene and ethane using partition coefficients and headspace-gas chromatography.

PubMed

Lomond, Jasmine S; Tong, Anthony Z

2011-01-01

Analysis of dissolved methane, ethylene, acetylene, and ethane in water is crucial in evaluating anaerobic activity and investigating the sources of hydrocarbon contamination in aquatic environments. A rapid chromatographic method based on phase equilibrium between water and its headspace is developed for these analytes. The new method requires minimal sample preparation and no special apparatus except those associated with gas chromatography. Instead of Henry's Law used in similar previous studies, partition coefficients are used for the first time to calculate concentrations of dissolved hydrocarbon gases, which considerably simplifies the calculation involved. Partition coefficients are determined to be 128, 27.9, 1.28, and 96.3 at 30°C for methane, ethylene, acetylene, and ethane, respectively. It was discovered that the volume ratio of gas-to-liquid phase is critical to the accuracy of the measurements. The method performance can be readily improved by reducing the volume ratio of the two phases. Method validation shows less than 6% variation in accuracy and precision except at low levels of methane where interferences occur in ambient air. Method detection limits are determined to be in the low ng/L range for all analytes. The performance of the method is further tested using environmental samples collected from various sites in Nova Scotia.

Distribution of polycyclic aromatic hydrocarbons in southern Chesapeake Bay surface water: Evaluation of three methods for determining freely dissolved water concentrations

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

Gustafson, K.E.; Dickhut, R.M.

1997-03-01

Gas sparging, semipermeable-membrane devices (SPMDs), and filtration with sorption of dissolved polycyclic aromatic hydrocarbons (PAHs) to XAD-2 resin were evaluated for determining the concentrations of freely dissolved PAHs in estuarine waters of southern Chesapeake Bay at sites ranging from rural to urban and highly industrialized. Gas sparging had significant sampling artifacts due to particle scavenging by rising bubbles, and SPMDs were kinetically limited for four-ring and larger PAHs relative to short-term temporal changes in water concentrations. Filtration with sorption of the dissolved contaminant fraction to XAD-2 resin was found to be the most accurate and feasible method for determining concentrationsmore » of freely dissolved PAHs in estuarine water. Concentrations and distribution coefficients of dissolved and particulate PAHs were measured using the filtration/XAD-2 method. Concentrations of PAHs in surface waters of southern Chesapeake Bay were higher than those reported for the northern bay; concentrations in the Elizabeth River were elevated relative to all other sites. A gradient for particulate PAHs was observed from urban to remote sites. No seasonal trends were observed in dissolved or particle-bound PAH fractions at any site. Distributions of dissolved and particulate PAHs in surface waters of the Chesapeake Bay are near equilibrium at all locations and during all seasons.« less

Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing

PubMed Central

Osborn, Stephen G.; Vengosh, Avner; Warner, Nathaniel R.; Jackson, Robert B.

2011-01-01

Directional drilling and hydraulic-fracturing technologies are dramatically increasing natural-gas extraction. In aquifers overlying the Marcellus and Utica shale formations of northeastern Pennsylvania and upstate New York, we document systematic evidence for methane contamination of drinking water associated with shale-gas extraction. In active gas-extraction areas (one or more gas wells within 1 km), average and maximum methane concentrations in drinking-water wells increased with proximity to the nearest gas well and were 19.2 and 64 mg CH4 L-1 (n = 26), a potential explosion hazard; in contrast, dissolved methane samples in neighboring nonextraction sites (no gas wells within 1 km) within similar geologic formations and hydrogeologic regimes averaged only 1.1 mg L-1 (P < 0.05; n = 34). Average δ13C-CH4 values of dissolved methane in shallow groundwater were significantly less negative for active than for nonactive sites (-37 ± 7‰ and -54 ± 11‰, respectively; P < 0.0001). These δ13C-CH4 data, coupled with the ratios of methane-to-higher-chain hydrocarbons, and δ2H-CH4 values, are consistent with deeper thermogenic methane sources such as the Marcellus and Utica shales at the active sites and matched gas geochemistry from gas wells nearby. In contrast, lower-concentration samples from shallow groundwater at nonactive sites had isotopic signatures reflecting a more biogenic or mixed biogenic/thermogenic methane source. We found no evidence for contamination of drinking-water samples with deep saline brines or fracturing fluids. We conclude that greater stewardship, data, and—possibly—regulation are needed to ensure the sustainable future of shale-gas extraction and to improve public confidence in its use. PMID:21555547

Total dissolved gas, barometric pressure, and water temperature data, lower Columbia River, Oregon and Washington, 1996

USGS Publications Warehouse

Tanner, Dwight Q.; Harrison, Howard E.; McKenzie, Stuart W.

1996-01-01

Increased levels of total dissolved gas pressure can cause gas-bubble trauma in fish downstream from dams on the Columbia River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey collected data on total dissolved gas pressure, barometric pressure, water temperature, and dissolved oxygen pressure at 11 stations on the lower Columbia River from the John Day forebay (river mile 215.6) to Wauna Mill (river mile 41.9) from March to September 1996. Methods of data collection, review, and processing are described in this report. Summaries of daily minimum, maximum, and mean hourly values are presented for total dissolved gas pressure, barometric pressure, and water temperature. Hourly values for these parameters are presented graphically. Dissolved oxygen data are not presented in this report because the quality-control data show that the data have poor precision and high bias. Suggested changes to monitoring procedures for future studies include (1) improved calibration procedures for total dissolved gas and dissolved oxygen to better define accuracy at elevated levels of supersaturation and (2) equipping dissolved oxygen sensors with stirrers because river velocities at the shoreline monitoring stations probably cannot maintain an adequate flow of water across the membrane surface of the dissolved oxygen sensor.

In Situ Raman Spectroscopic Observations of Gas-Saturated Rising Oil droplets: Simulation with Decane as an Oil-Equivalent Substitute

NASA Astrophysics Data System (ADS)

Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

2016-02-01

Oil droplets rising from the sea floor, whether from seeps or well leakage, contain very large quantities of dissolved gas that profoundly affects their density and critical oil-water interfacial characteristics. The primary dissolved gas is methane which may be up to 30% of the molar volume. This can create a hydrate skin as the methane gas is shed from the oil as it rises through the water column, thus decreasing in pressure and increasing in temperature, and steadily changing the rising droplet buoyancy. We have explored this phenomenon by executing controlled ROV based experiments with a "bubble cup" technique in which a small volume of gas saturated decane (saturated with pure methane, a mix of methane and nitrogen , or a mix of methane and CO2) is interrogated by laser Raman spectroscopy. The use of decane as an oil "substitute" is required since natural oil samples are highly fluorescent due to the presence of polycyclic aromatic hydrocarbons. We have devised Matlab techniques for extracting the spectroscopic dissolved methane signal from the thicket of decane peaks that surround it. We have directly observed the rate at which gases are lost from the "oil" per unit area at depths in the water column that are both within and outside the hydrate forming phase boundary. We have compared the behavior of both a non-hydrate forming dissolved gas (nitrogen) with CO2 where the hydrate phase boundary is at significantly shallower depth. The results indicate complex interfacial behavior and physical chemistry. We did not observe direct gas bubble formation on the decane outer surface but did observe gas bubble formation within the oil droplets as they rose through the water column. Because there are significant energy barriers for homogeneous bubble formation within the decane phase, we took this as evidence of significant gas super-saturation within the oil droplet. The gas loss rates increased significantly in all cases when the hydrate phase boundary was crossed.

Examination of Hydrate Formation Methods: Trying to Create Representative Samples

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

Kneafsey, T.J.; Rees, E.V.L.; Nakagawa, S.

2011-04-01

Forming representative gas hydrate-bearing laboratory samples is important so that the properties of these materials may be measured, while controlling the composition and other variables. Natural samples are rare, and have often experienced pressure and temperature changes that may affect the property to be measured [Waite et al., 2008]. Forming methane hydrate samples in the laboratory has been done a number of ways, each having advantages and disadvantages. The ice-to-hydrate method [Stern et al., 1996], contacts melting ice with methane at the appropriate pressure to form hydrate. The hydrate can then be crushed and mixed with mineral grains under controlledmore » conditions, and then compacted to create laboratory samples of methane hydrate in a mineral medium. The hydrate in these samples will be part of the load-bearing frame of the medium. In the excess gas method [Handa and Stupin, 1992], water is distributed throughout a mineral medium (e.g. packed moist sand, drained sand, moistened silica gel, other porous media) and the mixture is brought to hydrate-stable conditions (chilled and pressurized with gas), allowing hydrate to form. This method typically produces grain-cementing hydrate from pendular water in sand [Waite et al., 2004]. In the dissolved gas method [Tohidi et al., 2002], water with sufficient dissolved guest molecules is brought to hydrate-stable conditions where hydrate forms. In the laboratory, this is can be done by pre-dissolving the gas of interest in water and then introducing it to the sample under the appropriate conditions. With this method, it is easier to form hydrate from more soluble gases such as carbon dioxide. It is thought that this method more closely simulates the way most natural gas hydrate has formed. Laboratory implementation, however, is difficult, and sample formation is prohibitively time consuming [Minagawa et al., 2005; Spangenberg and Kulenkampff, 2005]. In another version of this technique, a specified quantity of gas is placed in a sample, then the sample is flooded with water and cooled [Priest et al., 2009]. We have performed a number of tests in which hydrate was formed and the uniformity of the hydrate formation was examined. These tests have primarily used a variety of modifications of the excess gas method to make the hydrate, although we have also used a version of the excess water technique. Early on, we found difficulties in creating uniform samples with a particular sand/ initial water saturation combination (F-110 Sand, {approx} 35% initial water saturation). In many of our tests we selected this combination intentionally to determine whether we could use a method to make the samples uniform. The following methods were examined: Excess gas, Freeze/thaw/form, Freeze/pressurize/thaw, Excess gas followed by water saturation, Excess water, Sand and kaolinite, Use of a nucleation enhancer (SnoMax), and Use of salt in the water. Below, each method, the underlying hypothesis, and our results are briefly presented, followed by a brief conclusion. Many of the hypotheses investigated are not our own, but were presented to us. Much of the data presented is from x-ray CT scanning our samples. The x-ray CT scanner provides a three-dimensional density map of our samples. From this map and the physics that is occurring in our samples, we are able to gain an understanding of the spatial nature of the processes that occur, and attribute them to the locations where they occur.« less

Controls on Methane Occurrences in Aquifers Overlying the Eagle Ford Shale Play, South Texas.

PubMed

Nicot, Jean-Philippe; Larson, Toti; Darvari, Roxana; Mickler, Patrick; Uhlman, Kristine; Costley, Ruth

2017-07-01

Assessing natural vs. anthropogenic sources of methane in drinking water aquifers is a critical issue in areas of shale oil and gas production. The objective of this study was to determine controls on methane occurrences in aquifers in the Eagle Ford Shale play footprint. A total of 110 water wells were tested for dissolved light alkanes, isotopes of methane, and major ions, mostly in the eastern section of the play. Multiple aquifers were sampled with approximately 47 samples from the Carrizo-Wilcox Aquifer (250-1200 m depth range) and Queen City-Sparta Aquifer (150-900 m depth range) and 63 samples from other shallow aquifers but mostly from the Catahoula Formation (depth <150 m). Besides three shallow wells with unambiguously microbial methane, only deeper wells show significant dissolved methane (22 samples >1 mg/L, 10 samples >10 mg/L). No dissolved methane samples exhibit thermogenic characteristics that would link them unequivocally to oil and gas sourced from the Eagle Ford Shale. In particular, the well water samples contain very little or no ethane and propane (C1/C2+C3 molar ratio >453), unlike what would be expected in an oil province, but they also display relatively heavier δ 13 C methane (>-55‰) and δD methane (>-180‰). Samples from the deeper Carrizo and Queen City aquifers are consistent with microbial methane sourced from syndepositional organic matter mixed with thermogenic methane input, most likely originating from deeper oil reservoirs and migrating through fault zones. Active oxidation of methane pushes δ 13 C methane and δD methane toward heavier values, whereas the thermogenic gas component is enriched with methane owing to a long migration path resulting in a higher C1/C2+C3 ratio than in the local reservoirs. © 2017, National Ground Water Association.

Sea Ice as a Sink for CO2 and Biogeochemical Material: a Novel Sampling Method and Astrobiological Applications

NASA Astrophysics Data System (ADS)

Wilner, J.; Hofmann, A.; Hand, K. P.

2017-12-01

Accurately modelling the intensification of greenhouse gas effects in the polar regions ("polar amplification") necessitates a thorough understanding of the geochemical balance between atmospheric, sea ice, and oceanic layers. Sea ice is highly permeable to CO2 and therefore represents a major sink of oceanic CO2 in winter and of atmospheric CO2 in summer, sinks that are typically either poorly constrained in or fully absent from global climate models. We present a novel method for sampling both trapped and dissolved gases (CO2, CH4 and δ13CH4) in sea ice with a Picarro 2132-i Methane Analyzer, taking the following sampling considerations into account: minimization of water and air contamination, full headspace sampling, prevention of inadvertent sample bag double-puncturing, and ease of use. This method involves melting of vacuum-sealed ice cores to evacuate trapped gases to the headspace and sampling the headspace gas with a blunt needle sheathed by a beveled puncturing needle. A gravity catchment tube prevents input of dangerous levels of liquid water to the Picarro cavity. Subsequent ultrasonic degassing allows for dissolved gas measurement. We are in the process of using this method to sample gases trapped and dissolved in Arctic autumn sea ice cores and atmospheric samples collected during the 2016 Polarstern Expedition and during a May 2017 field campaign north of Barrow, Alaska. We additionally employ this method, together with inductively coupled plasma mass spectrometry (ICP-MS), to analyze the transfer of potential biogeochemical signatures of underlying hydrothermal plumes to sea ice. This has particular relevance to Europa and Enceladus, where hypothetical hydrothermal plumes may deliver seafloor chemicals to the overlying ice shell. Hence, we are presently investigating the entrainment of methane and other hydrothermal material in sea ice cores collected along the Gakkel Ridge that may serve as biosignatures of methanogenic organisms in seafloor oases analogous to icy ocean worlds.

Method for the detection of nitro-containing compositions using ultraviolet photolysis

DOEpatents

Reagen, William K.; Lancaster, Gregory D.; Partin, Judy K.; Moore, Glenn A.

2000-01-01

A method for detecting nitro-containing compositions (e.g. nitrate/nitrite materials) in water samples and on solid substrates. In a water sample, ultraviolet light is applied to the sample so that dissolved nitro compositions therein will photolytically dissociate into gaseous nitrogen oxides (NO.sub.2(g) and/or NO.sub.(g)). A carrier gas is then introduced into the sample to generate a gaseous stream which includes the carrier gas combined with any gaseous nitrogen oxides. The carrier gas is thereafter directed into a detector. To detect nitro-compositions on solid substrates, ultraviolet light is applied thereto. A detector is then used to detect any gaseous nitrogen oxides which are photolytically generated during ultraviolet illumination. An optional carrier gas may be applied to the substrate during illumination to produce a gaseous stream which includes the carrier gas and any gaseous nitrogen oxides. The gaseous stream is then supplied to the detector.

Methane Sources and Migration Mechanisms in Shallow Groundwaters in Parker and Hood Counties, Texas-A Heavy Noble Gas Analysis.

PubMed

Wen, Tao; Castro, M Clara; Nicot, Jean-Philippe; Hall, Chris M; Larson, Toti; Mickler, Patrick; Darvari, Roxana

2016-11-01

This study places constraints on the source and transport mechanisms of methane found in groundwater within the Barnett Shale footprint in Texas using dissolved noble gases, with particular emphasis on 84 Kr and 132 Xe. Dissolved methane concentrations are positively correlated with crustal 4 He, 21 Ne, and 40 Ar and suggest that noble gases and methane originate from common sedimentary strata, likely the Strawn Group. In contrast to most samples, four water wells with the highest dissolved methane concentrations unequivocally show strong depletion of all atmospheric noble gases ( 20 Ne, 36 Ar, 84 Kr, 132 Xe) with respect to air-saturated water (ASW). This is consistent with predicted noble gas concentrations in a water phase in contact with a gas phase with initial ASW composition at 18 °C-25 °C and it suggests an in situ, highly localized gas source. All of these four water wells tap into the Strawn Group and it is likely that small gas accumulations known to be present in the shallow subsurface were reached. Additionally, lack of correlation of 84 Kr/ 36 Ar and 132 Xe/ 36 Ar fractionation levels along with 4 He/ 20 Ne with distance to the nearest gas production wells does not support the notion that methane present in these groundwaters migrated from nearby production wells either conventional or using hydraulic fracturing techniques.

Dissolved pesticides, dissolved organic carbon, and water-quality characteristics in selected Idaho streams, April--December 2010

USGS Publications Warehouse

Reilly, Timothy J.; Smalling, Kelly L.; Wilson, Emma R.; Battaglin, William A.

2012-01-01

Water-quality samples were collected from April through December 2010 from four streams in Idaho and analyzed for a suite of pesticides, including fungicides, by the U.S. Geological Survey. Water samples were collected from two agricultural and two nonagricultural (control) streams approximately biweekly from the beginning of the growing season (April) through the end of the calendar year (December). Samples were analyzed for 90 pesticides using gas chromatography/mass spectrometry. Twenty-three pesticides, including 8 fungicides, 10 herbicides, 3 insecticides, and 2 pesticide degradates, were detected in 45 water samples. The most frequently detected compounds in the two agricultural streams and their detection frequencies were metolachlor, 96 percent; azoxystrobin, 79 percent; boscalid, 79 percent; atrazine, 46 percent; pendimethalin, 33 percent; and trifluralin, 33 percent. Dissolved-pesticide concentrations ranged from below instrumental limits of detection (0.5-1.0 nanograms per liter) to 771 nanograms per liter (hexazinone). The total number of pesticides detected in any given water sample ranged from 0 to 11. Only three pesticides (atrazine, fipronil, and simazine) were detected in samples from the control streams during the sampling period.

A gas chromatographic method for the determination of bicarbonate and dissolved gases

USDA-ARS?s Scientific Manuscript database

A gas chromatographic method for the rapid determination of aqueous carbon dioxide and its speciation into solvated carbon dioxide and bicarbonate is presented. One-half mL samples are injected through a rubber septum into 20-mL vials that are filled with 9.5 mL of 0.1 N HCl. A one mL portion of the...

Application and evaluation of scale dissolver treatments

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

Fielder, G.D.

1994-12-31

In order to provide an improved basis for the design of barium sulfate scale dissolver treatments both laboratory testing and monitoring of field applications were carried out. The deleterious effects of mixing produced water with dissolver prior to contacting scale are shown. Increasing total dissolved solids (TDS) levels can reduce dissolution depending upon temperature. Precomplexation with divalent cations reduces the capacity of the dissolver to solubilize solid scales. Magnesium may adversely affect dissolver performance at elevated temperatures. Several oil and gas wells were closely monitored during initial flowback after treatment. Samples were collected on a frequent basis and analyzed formore » pH, dissolver content, chlorides and various cations. The resulting data were used to construct flowback profiles for evaluation of the treatments. Evidence of scale dissolution is presented. The presence of an incompatible flush brine was discovered in one case and possible reverse order of addition of preflush and dissolver in another. The importance of establishing and following treatment procedures is briefly discussed.« less

Geochemical Characteristics of Aquifer system in Taichung Area, Central Taiwan

NASA Astrophysics Data System (ADS)

Tsai, Jui-Fen; Chen, Cheng-Hong; Liu, Tsung-Kwei

2016-04-01

For understanding the relationship between water bodies and host rocks and getting more information for groundwater in Taichung area, Central Taiwan, we systematically analyzed the stable isotopes (hydrogen and oxygen), helium isotopes and radon concentrations of dissolved gases from 54 groundwater, 39 river and 4 rain samples collected from Taichung Basin in wet and dry seasons of the year 2015. In the δ18O vs. δD plot, all samples present a linear trend similar to local meteoric water, indicating a meteoric origin. However, river samples are relative lighter than rain samples, it appears that the rivers are mainly recharged from precipitation of high-elevation areas with a lighter isotopic composition. Because the seasonal isotopic variation of river samples is significant, we calculated relative contribution of precipitation by seasons using the mass balance equation. Results show that the precipitation in the rainy season is the major source of groundwater. The helium isotopic ratio in dissolved gases of most groundwater samples are close to 1 RA (RA = 3He/4He ratio of air), except the sample from Wu-Feng well that exhibits 0.3 RA. This sample also has an older C-14 age (˜27000 yrs.) than others (<200 yrs.), implying that the dissolved helium is likely affected by radiogenic 4He of surrounding rocks. The average concentration of radon for groundwater in the northern section of Taichung Basin is 20.3 Bq/L, which is higher than that of the southern section (14.5 Bq/L). Variations of radon concentrations in the two sections may be related to the different drainage systems (Paleo-Dajia River vs. Wu River), in which sediments from Paleo-Dajia River may contain higher uranium concentrations. On the other hand, water in rivers usually contains undetectable radon (<0.37 Bq/L) because it rapidly escapes to the atmosphere. However, river samples from the central part of basin have radon concentrations ranging between 1 and 3 Bq/L, reflecting that the sampling sites are in the vicinity of points of groundwater inflow. This study illustrates the utility of hydrogen and oxygen isotopes to trace the groundwater source and determine the seasonal contribution ratios of precipitation to groundwater recharge, and demonstrates the advantage of using dissolved gas to investigate the groundwater-host rocks interaction. Key words: Central Taiwan, groundwater, dissolved gas, helium isotope, hydrogen and oxygen isotopes, water radon

Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

USGS Publications Warehouse

Révész, Kinga M.; Doctor, Daniel H.

2014-01-01

The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

Laboratory formation of non-cementing, methane hydrate-bearing sands

USGS Publications Warehouse

Waite, William F.; Bratton, Peter M.; Mason, David H.

2011-01-01

Naturally occurring hydrate-bearing sands often behave as though methane hydrate is acting as a load-bearing member of the sediment. Mimicking this behavior in laboratory samples with methane hydrate likely requires forming hydrate from methane dissolved in water. To hasten this formation process, we initially form hydrate in a free-gas-limited system, then form additional hydrate by circulating methane-supersaturated water through the sample. Though the dissolved-phase formation process can theoretically be enhanced by increasing the pore pressure and flow rate and lowering the sample temperature, a more fundamental concern is preventing clogs resulting from inadvertent methane bubble formation in the circulation lines. Clog prevention requires careful temperature control throughout the circulation loop.

Baseline groundwater quality from 20 domestic wells in Sullivan County, Pennsylvania, 2012

USGS Publications Warehouse

Sloto, Ronald A.

2013-01-01

Concentrations of dissolved methane ranged from less than 0.001 to 51.1 mg/L. Methane was not detected in water samples from 13 wells, and the methane concentration was less than 0.07 mg/L in samples from five wells. The highest dissolved methane concentrations were 4.1 and 51.1 mg/L, and the pH of the water from both wells was greater than 8. Water samples from these wells were analyzed for isotopes of carbon and hydrogen in the methane. The isotopic ratio values fell in the range for a thermogenic (natural gas) source. The water samples from these two wells had the highest concentrations of arsenic, boron, bromide, chloride, fluoride, lithium, molybdenum, and sodium of the 20 wells sampled.

Dissolved pesticides in the Alamo River and the Salton Sea, California, 1996-97

USGS Publications Warehouse

Crepeau, Kathryn L.; Kuivila, Kathryn; Bergamaschi, Brian A.

2002-01-01

Water samples were collected from the Alamo River and the Salton Sea, California, in autumn 1996 and late winter/early spring 1997 and analyzed for dissolved pesticides. The two seasons chosen for sampling were during pesticide application periods in the Imperial Valley. Pesticide concentrations were measured in filtered water samples using solid-phase extraction and analyzed by gas chromatography/mass spectrometry. Generally, the highest concentrations were measured in the Alamo River. The concentrations of carbaryl, chlorpyrifos, cycloate, dacthal, diazinon, and eptam were highest in samples collected in autumn 1996. In contrast, the concentrations of atrazine, carbofuran, and malathion were highest in samples collected in late winter/early spring 1997. The highest concentrations measured of atrazine, carbofuran, dacthal, eptam, and malathion all exceeded 1,000 nanograms per liter.

Dissolved gases in hydrothermal (phreatic) and geyser eruptions at Yellowstone National Park, USA

USGS Publications Warehouse

Hurwitz, Shaul; Clor, Laura; McCleskey, R. Blaine; Nordstrom, D. Kirk; Hunt, Andrew G.; Evans, William C.

2016-01-01

Multiphase and multicomponent fluid flow in the shallow continental crust plays a significant role in a variety of processes over a broad range of temperatures and pressures. The presence of dissolved gases in aqueous fluids reduces the liquid stability field toward lower temperatures and enhances the explosivity potential with respect to pure water. Therefore, in areas where magma is actively degassing into a hydrothermal system, gas-rich aqueous fluids can exert a major control on geothermal energy production, can be propellants in hazardous hydrothermal (phreatic) eruptions, and can modulate the dynamics of geyser eruptions. We collected pressurized samples of thermal water that preserved dissolved gases in conjunction with precise temperature measurements with depth in research well Y-7 (maximum depth of 70.1 m; casing to 31 m) and five thermal pools (maximum depth of 11.3 m) in the Upper Geyser Basin of Yellowstone National Park, USA. Based on the dissolved gas concentrations, we demonstrate that CO2 mainly derived from magma and N2 from air-saturated meteoric water reduce the near-surface saturation temperature, consistent with some previous observations in geyser conduits. Thermodynamic calculations suggest that the dissolved CO2 and N2 modulate the dynamics of geyser eruptions and are likely triggers of hydrothermal eruptions when recharged into shallow reservoirs at high concentrations. Therefore, monitoring changes in gas emission rate and composition in areas with neutral and alkaline chlorine thermal features could provide important information on the natural resources (geysers) and hazards (eruptions) in these areas.

Origins of hydrocarbon gas seeping out from offshore mud volcanoes in the Nile delta

NASA Astrophysics Data System (ADS)

Prinzhofer, Alain; Deville, Eric

2013-04-01

This paper discusses the origin of gas seepages (free gas or dissolved gas in ground water or brine) sampled with the Nautile submarine during the Nautinil cruise at the seafloor of the deep water area of the Nile turbiditic system on different mud volcanoes and brine pools. Generally, the gas is wet and includes C1, C2, C3, iC4, nC4, CO2. These gas samples show no evidence of biodegradation which is not the case of the gas present in the deep hydrocarbon accumulations at depth. It indicates that the gas expelled by the mud volcanoes is not issued from direct leakages from deep gas fields. The collected gas samples mainly have a thermogenic origin and show different maturities. Some samples show very high maturities indicating that these seepages are sourced from great depths, below the Messinian salt. Moreover, the different chemical compositions of the gas samples reflect not only differences in maturity but also the fact that the gas finds its origin in different deep source rocks. Carbon dioxide has an organic signature and cannot result from carbonate decomposition or mantle fluids. The crustal-derived radiogenic isotopes show that the analyzed gas samples have suffered a fractionation processes after the production of the radiogenic isotopes, due either to oil occurrence at depth interacting with the flux of gas, and/or fractionation during the fluid migration.

Chemical analyses of geothermal waters from a South Louisiana well

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

Hankins, B.E.; Chavanne, R.E.; Ham, R.A.

1977-11-16

The abandoned Edna Delcambre No. 1 gas well, about 8 miles south of Delcambre, Louisiana was reopened and bottom-hole and flowing samples were collected. McNeese State University was responsible for the analyses of the products of the well. Typical values from the analyses are shown for such quantities as: pH, turbidity, conductance, density, total dissolved solids, hardness, viscosity, dissolved silicates, chlorides, bicarbonates, etc. Some observations on these values are made. (MHR)

Determination of dissolved methane in natural waters using headspace analysis with cavity ring-down spectroscopy.

PubMed

Roberts, Hannah M; Shiller, Alan M

2015-01-26

Methane (CH4) is the third most abundant greenhouse gas (GHG) but is vastly understudied in comparison to carbon dioxide. Sources and sinks to the atmosphere vary considerably in estimation, including sources such as fresh and marine water systems. A new method to determine dissolved methane concentrations in discrete water samples has been evaluated. By analyzing an equilibrated headspace using laser cavity ring-down spectroscopy (CRDS), low nanomolar dissolved methane concentrations can be determined with high reproducibility (i.e., 0.13 nM detection limit and typical 4% RSD). While CRDS instruments cost roughly twice that of gas chromatographs (GC) usually used for methane determination, the process presented herein is substantially simpler, faster, and requires fewer materials than GC methods. Typically, 70-mL water samples are equilibrated with an equivalent amount of zero air in plastic syringes. The equilibrated headspace is transferred to a clean, dry syringe and then drawn into a Picarro G2301 CRDS analyzer via the instrument's pump. We demonstrate that this instrument holds a linear calibration into the sub-ppmv methane concentration range and holds a stable calibration for at least two years. Application of the method to shipboard dissolved methane determination in the northern Gulf of Mexico as well as river water is shown. Concentrations spanning nearly six orders of magnitude have been determined with this method. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of the δ34S of sulfate in water; RSIL lab code 1951

USGS Publications Warehouse

Revesz, Kinga; Qi, Haiping; Coplen, Tyler B.

2006-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1951 is to determine the δ(34S/32S), abbreviated as δ34S, of dissolved sulfate. Dissolved sulfate is collected in the field and precipitated with BaCl2 at pH 3 to 4 as BaSO4 in the laboratory. However, the dissolved organic sulfur (DOS) is oxidized to SO2, and the carbonate is acidified to CO2. Both are degassed from the water sample before the sulfate is precipitated. The precipitated BaSO4 is filtered and dried before introduction into an elemental analyzer (EA) Carlo Erba NC 2500. The EA is used to convert sulfur in a BaSO4 solid sample into SO2 gas, and the EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines the differences in the isotope-amount ratios of stable sulfur isotopes (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in a tin capsule and loaded into the Costech Zero Blank Autosampler of the EA. Under computer control, samples are dropped into a heated tube reaction tube that combines the oxidation and reduction reactions. The combustion takes place in a helium atmosphere containing an excess of oxygen gas at the oxidation zone at the top of the reaction tube. Combustion products are transported by a helium carrier through the reduction zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph. The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through a Finnigan MAT (now Thermo Scientific) ConFlo II interface, which also is used to inject SO2 reference gas and helium for sample dilution. The IRMS is a Thermo Scientific Delta V Plus CF-IRMS. It has a universal triple collector with two wide cups and a narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion beams from SO2 are as follows: m/z 64 = SO2 = 32S16O16O; m/z 66 = SO2 = 34S16O16O primarily.

Recharge processes and vertical transfer investigated through long-term monitoring of dissolved gases in shallow groundwater

NASA Astrophysics Data System (ADS)

de Montety, V.; Aquilina, L.; Labasque, T.; Chatton, E.; Fovet, O.; Ruiz, L.; Fourré, E.; de Dreuzy, J. R.

2018-05-01

We investigated temporal variations and vertical evolution of dissolved gaseous tracers (CFC-11, CFC-12, SF6, and noble gases), as well as 3H/3He ratio to determine groundwater recharge processes of a shallow unconfined, hard-rock aquifer in an agricultural catchment. We sampled dissolved gas concentration at 4 locations along the hillslope of a small experimental watershed, over 6 hydrological years, between 2 and 6 times per years, for a total of 20 field campaigns. We collected groundwater samples in the fluctuation zone and the permanently saturated zone using piezometers from 5 to 20 m deep. The purpose of this work is i) to assess the benefits of using gaseous tracers like CFCs and SF6 to study very young groundwater with flows suspected to be heterogeneous and variable in time, ii) to characterize the processes that control dissolved gas concentrations in groundwater during the recharge of the aquifer, and iii) to understand the evolution of recharge flow processes by repeated measurement campaigns, taking advantage of a long monitoring in a site devoted to recharge processes investigation. Gas tracer profiles are compared at different location of the catchment and for different hydrologic conditions. In addition, we compare results from CFCs and 3H/3He analysis to define the flow model that best explains tracer concentrations. Then we discuss the influence of recharge events on tracer concentrations and residence time and propose a temporal evolution of residence times for the unsaturated zone and the permanently saturated zone. These results are used to gain a better understanding of the conceptual model of the catchment and flow processes especially during recharge events.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1989-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1990-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

PubMed Central

K. S., Nagapriya; Sinha, Shashank; R., Prashanth; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

2017-01-01

In this paper we report a newly developed technique – laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region. PMID:28218304

Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis.

PubMed

K S, Nagapriya; Sinha, Shashank; R, Prashanth; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

2017-02-20

In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

Organic compounds in radiation fogs in Davis (California)

NASA Astrophysics Data System (ADS)

Herckes, Pierre; Hannigan, Michael P.; Trenary, Laurie; Lee, Taehyoung; Collett, Jeffrey L.

New stainless steel active fogwater collectors were designed and used in Davis (CA, USA) to collect fogwater for the speciation of organic matter. Organic compounds in fog samples were extracted by liquid-liquid extraction and analyzed by gas chromatography coupled to mass spectrometry. Numerous organic compounds, including various alkanes, polycyclic aromatic hydrocarbons (PAH) and alkanoic acids, have been identified in the fogwater samples. Higher molecular weight (MW) compounds are preferentially associated with an insoluble phase inside the fog drops, whereas lower molecular weight and more polar compounds are found predominantly in the dissolved phase. Concentrations in the dissolved phase were sometimes much higher than estimated by the compounds' aqueous solubilities.

Rapid assessment of pulmonary gas transport with hyperpolarized 129Xe MRI using a 3D radial double golden-means acquisition with variable flip angles.

PubMed

Ruppert, Kai; Amzajerdian, Faraz; Hamedani, Hooman; Xin, Yi; Loza, Luis; Achekzai, Tahmina; Duncan, Ian F; Profka, Harrilla; Siddiqui, Sarmad; Pourfathi, Mehrdad; Cereda, Maurizio F; Kadlecek, Stephen; Rizi, Rahim R

2018-04-22

To demonstrate the feasibility of using a 3D radial double golden-means acquisition with variable flip angles to monitor pulmonary gas transport in a single breath hold with hyperpolarized xenon-129 MRI. Hyperpolarized xenon-129 MRI scans with interleaved gas-phase and dissolved-phase excitations were performed using a 3D radial double golden-means acquisition in mechanically ventilated rabbits. The flip angle was either held fixed at 15 ° or 5 °, or it was varied linearly in ascending or descending order between 5 ° and 15 ° over a sampling interval of 1000 spokes. Dissolved-phase and gas-phase images were reconstructed at high resolution (32 × 32 × 32 matrix size) using all 1000 spokes, or at low resolution (22 × 22 × 22 matrix size) using 400 spokes at a time in a sliding-window fashion. Based on these sliding-window images, relative change maps were obtained using the highest mean flip angle as the reference, and aggregated pixel-based changes were tracked. Although the signal intensities in the dissolve-phase maps were mostly constant in the fixed flip-angle acquisitions, they varied significantly as a function of average flip angle in the variable flip-angle acquisitions. The latter trend reflects the underlying changes in observed dissolve-phase magnetization distribution due to pulmonary gas uptake and transport. 3D radial double golden-means acquisitions with variable flip angles provide a robust means for rapidly assessing lung function during a single breath hold, thereby constituting a particularly valuable tool for imaging uncooperative or pediatric patient populations. © 2018 International Society for Magnetic Resonance in Medicine.

Preliminary Study: Application of Off-Axis ICOS to Determine Stable Carbon Isotope in Dissolved Inorganic Carbon

NASA Astrophysics Data System (ADS)

Kim, Y. T.; Lee, J. M.; Hwang, J. H.; Piao, J.; Woo, N. C.

2015-12-01

CO2 is one of the major causes for global climate change. Because stable carbon isotope ratio is used to trace carbon source, several analytical techniques likes IRMS (Isotope Ratio Mass Spectrometry) and LAS (Laser Absorption Spectrometry) were extensively used. Off-axis ICOS, a kind of LAS, has merits on long-term stability and field application, therefore it is widely being used in CCS (Carbon Capture and Storage) field. The aim of this study is to extend the application scope of OA-ICOS to determine dissolved inorganic carbon (DIC). Because OA-ICOS showed dependence of δ13C on CO2 concentration, data processing is required. We tested CO2 Carbon Isotope Analyzer (CCIA-36-EP, Los Gatos Research) with both reference gas (δ13C= -28.28‰) and aqueous solutions prepared by dissolving sodium bicarbonate standards (δ13C= -12.26‰ and +3.96‰). The differences of δ13C between reference and measurement values are plotted by CO2 concentrations, then compared. At first, we checked the similarity between our curve pattern for reference gas and Guillon's research (δ13C= -43.99‰) by other Analyzer. To analyze aqueous samples, more errors can be caused than gas analysis. The carbon isotope fractionation occurs during dissolving standard reagents and extracting DIC as CO2 gas form. This effect is mixed with CO2 concentration dependence effect, therefore the curve patterns are different with that for reference gas. Our experiments are done for various δ13C values. It could be an important point to use OA-ICOS to analyze DIC, too.

Popping rocks from the Mid-Atlantic Ridge: Insights into mantle volatile concentrations and degassing dynamics

NASA Astrophysics Data System (ADS)

Jones, M.; Soule, S. A.; Kurz, M. D.; Wanless, V. D.; Le Roux, V.; Klein, F.; Mittelstaedt, E. L.; Curtice, J.

2016-12-01

During a 1985 cruise, the Mid-Atlantic Ridge (MAR) near 14°N yielded an unusually vesicular mid-ocean ridge (MOR) basalt that popped upon recovery from the seafloor due to the release of trapped volatiles. This `popping rock' has been inferred to be representative of primitive, undegassed magmas from the upper mantle due to its high volatile concentrations. Thus, the sample has been used to constrain CO2 flux from the MOR system, upper mantle volatile concentrations, and magma degassing dynamics. However, the lack of geologic context for the original popping rock raises questions about whether it truly reflects the volatile content of its mantle source. Here, we present results from a 2016 cruise to the MAR aimed at characterizing the geologic context of popping rocks and understanding their origins. The newly recovered samples display differences in volatile concentrations and vesicularities between popping and non-popping rocks. These differences may be related to geologic setting and eruption dynamics with potential implications for mantle volatile concentrations. Volatile concentrations in the outer quenched margin of new samples were measured by ion microprobe to elucidate degassing systematics, brine/magma interactions, and popping rock formation. The large variability in dissolved H2O (0.05-0.77 wt%) can be attributed to spatially variable brine contamination. Dissolved CO2 concentrations (153-356 ppm) are likely controlled by initial volatile concentrations and variable degrees of degassing. The subset of popping samples display low dissolved CO2 concentrations (161-178 ppm) and moderate dissolved H2O concentrations (.44-.50 wt%) and are at equilibrium with their eruption depth based on solubility calculations. X-ray microtomography reveals vesicularity in newly collected popping rocks exceeding 19%, making these samples the most highly vesicular recovered from the MAR. The total gas contents in the basaltic glasses are inferred from dissolved volatile concentrations and vesicularity. These calculations are aided by analysis of gas contents in vesicles by confocal Raman spectroscopy and vacuum crushing experiments. The preliminary results and seafloor observations allow an evaluation of the origins of popping rocks and their implications for mantle volatile concentrations.

GAS CHROMATOGRAPHY-MASS SPECTROMETRY MEASUREMENT OF XENON IN GAS-LOADED LIPOSOMES FOR NEUROPROTECTIVE APPLICATIONS1

PubMed Central

Klegerman, Melvin E.; Moody, Melanie R.; Hurling, Jermaine R.; Peng, Tao; Huang, Shao-Ling; McPherson, David D.

2016-01-01

Rationale We have produced a liposomal formulation of xenon (Xe-ELIP) as a neuroprotectant for inhibition of brain damage in stroke patients. This mandates development of a reliable assay to measure the amount of dissolved xenon released from Xe-ELIP in water and blood samples. Methods Gas chromatography-Mass Spectrometry (GC-MS) was used to quantify xenon gas released into the headspace of vials containing Xe-ELIP samples in water or blood. In order to determine blood concentration of xenon in vivo after Xe-ELIP administration, 6 mg Xe-ELIP lipid was infused intravenously into rats. Blood samples were drawn directly from a catheterized right carotid artery. After introduction of the samples, each vial was allowed to equilibrate to 37° C in a water bath, followed by 20 minutes of sonication prior to headspace sampling. Xenon concentrations were calculated from a gas dose-response curve and normalized using the published xenon water-gas solubility coefficient. Results The mean corrected percent of xenon from Xe-ELIP released into water was 3.87 ± 0.56% (SD, n = 8), corresponding to 19.3 ± 2.8 μl/mg lipid, which is consistent with previous independent Xe-ELIP measurements. The corresponding xenon content of Xe-ELIP in rat blood was 23.38 ± 7.36 μl/mg lipid (n = 8). Mean rat blood xenon concentration after IV administration of Xe-ELIP was 14 ± 10 μM, which is approximately 15% of the estimated neuroprotective level. Conclusions Using this approach, we have established a reproducible method for measuring dissolved xenon in fluids. These measurements have established that neuroprotective effects can be elicited by less than 20% of the calculated neuroprotective xenon blood concentration. More work will have to be done to establish the protective xenon pharmacokinetic range. PMID:27689777

Gas chromatography/mass spectrometry measurement of xenon in gas-loaded liposomes for neuroprotective applications.

PubMed

Klegerman, Melvin E; Moody, Melanie R; Hurling, Jermaine R; Peng, Tao; Huang, Shao-Ling; McPherson, David D

2017-01-15

We have produced a liposomal formulation of xenon (Xe-ELIP) as a neuroprotectant for inhibition of brain damage in stroke patients. This mandates development of a reliable assay to measure the amount of dissolved xenon released from Xe-ELIP in water and blood samples. Gas chromatography/mass spectrometry (GC/MS) was used to quantify xenon gas released into the headspace of vials containing Xe-ELIP samples in water or blood. In order to determine blood concentration of xenon in vivo after Xe-ELIP administration, 6 mg of Xe-ELIP lipid was infused intravenously into rats. Blood samples were drawn directly from a catheterized right carotid artery. After introduction of the samples, each vial was allowed to equilibrate to 37°C in a water bath, followed by 20 minutes of sonication prior to headspace sampling. Xenon concentrations were calculated from a gas dose-response curve and normalized using the published xenon water-gas solubility coefficient. The mean corrected percent of xenon from Xe-ELIP released into water was 3.87 ± 0.56% (SD, n = 8), corresponding to 19.3 ± 2.8 μL/mg lipid, which is consistent with previous independent Xe-ELIP measurements. The corresponding xenon content of Xe-ELIP in rat blood was 23.38 ± 7.36 μL/mg lipid (n = 8). Mean rat blood xenon concentration after intravenous administration of Xe-ELIP was 14 ± 10 μM, which is approximately 15% of the estimated neuroprotective level. Using this approach, we have established a reproducible method for measuring dissolved xenon in fluids. These measurements have established that neuroprotective effects can be elicited by less than 20% of the calculated neuroprotective xenon blood concentration. More work will have to be done to establish the protective xenon pharmacokinetic range. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Screening for Dissolved Methane in Groundwater Across Texas Shale Plays

NASA Astrophysics Data System (ADS)

Nicot, J. P.; Mickler, P. J.; Hildenbrand, Z.; Larson, T.; Darvari, R.; Uhlman, K.; Smyth, R. C.; Scanlon, B. R.

2014-12-01

There is considerable interest in methane concentrations in groundwater, particularly as they relate to hydraulic fracturing in shale plays. Recent studies of aquifers in the footprint of several gas plays across the US have shown that (1) dissolved thermogenic methane may or may not be present in the shallow groundwater and (2) shallow thermogenic methane may be naturally occurring and emplaced through mostly vertical migration over geologic time and not necessarily a consequence of recent unconventional gas production. We are currently conducting a large sampling campaign across the state of Texas to characterize shallow methane in fresh-water aquifers overlying shale plays and other tight formations. We collected a total of ~800 water samples, ~500 in the Barnett, ~150 in the Eagle Ford, ~80 in the Haynesville shale plays as well as ~50 in the Delaware Basin of West Texas. Preliminary analytical results suggest that dissolved methane is not widespread in shallow groundwater and that, when present at concentrations exceeding 10 mg/L, it is often of thermogenic origin according to the isotopic signature and to the presence of other light hydrocarbons. The Barnett Shale contains a large methane hotspot (~ 2 miles wide) along the Hood-Parker county line which is likely of natural origin whereas the Eagle Ford and Haynesville shales, neglecting microbial methane, show more distributed methane occurrences. Samples from the Delaware Basin show no methane except close to blowouts.

Controls on Methane Occurrences in Shallow Aquifers Overlying the Haynesville Shale Gas Field, East Texas.

PubMed

Nicot, Jean-Philippe; Larson, Toti; Darvari, Roxana; Mickler, Patrick; Slotten, Michael; Aldridge, Jordan; Uhlman, Kristine; Costley, Ruth

2017-07-01

Understanding the source of dissolved methane in drinking-water aquifers is critical for assessing potential contributions from hydraulic fracturing in shale plays. Shallow groundwater in the Texas portion of the Haynesville Shale area (13,000 km 2 ) was sampled (70 samples) for methane and other dissolved light alkanes. Most samples were derived from the fresh water bearing Wilcox formations and show little methane except in a localized cluster of 12 water wells (17% of total) in a approximately 30 × 30 km 2 area in Southern Panola County with dissolved methane concentrations less than 10 mg/L. This zone of elevated methane is spatially associated with the termination of an active fault system affecting the entire sedimentary section, including the Haynesville Shale at a depth more than 3.5 km, and with shallow lignite seams of Lower Wilcox age at a depth of 100 to 230 m. The lignite spatial extension overlaps with the cluster. Gas wetness and methane isotope compositions suggest a mixed microbial and thermogenic origin with contribution from lignite beds and from deep thermogenic reservoirs that produce condensate in most of the cluster area. The pathway for methane from the lignite and deeper reservoirs is then provided by the fault system. © 2017, National Ground Water Association.

Probing the regional distribution of pulmonary gas exchange through single-breath gas- and dissolved-phase 129Xe MR imaging.

PubMed

Kaushik, S Sivaram; Freeman, Matthew S; Cleveland, Zackary I; Davies, John; Stiles, Jane; Virgincar, Rohan S; Robertson, Scott H; He, Mu; Kelly, Kevin T; Foster, W Michael; McAdams, H Page; Driehuys, Bastiaan

2013-09-01

Although some central aspects of pulmonary function (ventilation and perfusion) are known to be heterogeneous, the distribution of diffusive gas exchange remains poorly characterized. A solution is offered by hyperpolarized 129Xe magnetic resonance (MR) imaging, because this gas can be separately detected in the lung's air spaces and dissolved in its tissues. Early dissolved-phase 129Xe images exhibited intensity gradients that favored the dependent lung. To quantitatively corroborate this finding, we developed an interleaved, three-dimensional radial sequence to image the gaseous and dissolved 129Xe distributions in the same breath. These images were normalized and divided to calculate "129Xe gas-transfer" maps. We hypothesized that, for healthy volunteers, 129Xe gas-transfer maps would retain the previously observed posture-dependent gradients. This was tested in nine subjects: when the subjects were supine, 129Xe gas transfer exhibited a posterior-anterior gradient of -2.00 ± 0.74%/cm; when the subjects were prone, the gradient reversed to 1.94 ± 1.14%/cm (P < 0.001). The 129Xe gas-transfer maps also exhibited significant heterogeneity, as measured by the coefficient of variation, that correlated with subject total lung capacity (r = 0.77, P = 0.015). Gas-transfer intensity varied nonmonotonically with slice position and increased in slices proximal to the main pulmonary arteries. Despite substantial heterogeneity, the mean gas transfer for all subjects was 1.00 ± 0.01 while supine and 1.01 ± 0.01 while prone (P = 0.25), indicating good "matching" between gas- and dissolved-phase distributions. This study demonstrates that single-breath gas- and dissolved-phase 129Xe MR imaging yields 129Xe gas-transfer maps that are sensitive to altered gas exchange caused by differences in lung inflation and posture.

Headspace gas chromatography with flame ionization detection (HS-GC-FID) for the determination of dissolved methane in wastewater.

PubMed

Beale, D J; Tjandraatmadja, G; Toifl, M; Goodman, N

2014-01-01

There is currently a need for a simple, accurate and reproducible method that quantifies the amount of dissolved methane in wastewater in order to realize the potential methane that can be recovered and account for any emissions. This paper presents such a method, using gas chromatography with flame ionization detection fitted with a GS-Gas PRO column coupled with a headspace auto sampler. A practical limit of detection for methane of 0.9 mg L(-1), with a retention time of 1.24 min, was obtained. It was found that the reproducibility and accuracy of the method increased significantly when samples were collected using an in-house constructed bailer sampling device and with the addition of 100 μL hydrochloric acid (HCl) and 25% sodium chloride (NaCl) and sonication for 30 min prior to analysis. Analysis of wastewater samples and wastewater sludge collected from a treatment facility were observed to range from 12.51 to 15.79 mg L(-1) (relative standard deviation (RSD) 8.1%) and 17.56 to 18.67 mg L(-1) (RSD 3.4%) respectively. The performance of this method was validated by repeatedly measuring a mid-level standard (n=8; 10 mg L(-1)), with an observed RSD of 4.6%.

Comparison of depth-specific groundwater sampling methods and their influence on hydrochemistry, isotopy and dissolved gases - Experiences from the Fuhrberger Feld, Germany

NASA Astrophysics Data System (ADS)

Houben, Georg J.; Koeniger, Paul; Schloemer, Stefan; Gröger-Trampe, Jens; Sültenfuß, Jürgen

2018-02-01

Depth-specific sampling of groundwater is important for a variety of hydrogeological applications. Several sampling methods are available but comparably little is known about how their results compare. Therefore, samples from regular observation wells (short screen), micro-filters and direct push were compared for two sites with differing hydrogeological conditions and land use, both located in the Fuhrberger Feld, Germany. The encountered hydrochemical zonation requires a high resolution of 1 m or better, which the available small number of regular observation wells could only roughly mirror. Because the three methods employ significantly varying pumping rates and therefore, have varying spatial origins of the sample, individual concentrations at similar depths may differ significantly. In a hydrologically and chemically dynamical environment such as the agricultural site, this effect becomes more pronounced than for the more stable forest site. The micro-filters are probably the most depth-specific, but showed distinctly lower concentrations for dissolved gases than the other two methods, due to degassing during sampling. They should thus not be used for any method that relies on dissolved gas analysis.

Detection of hydrogen dissolved in acrylonitrile butadiene rubber by 1H nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Nishimura, Shin; Fujiwara, Hirotada

2012-01-01

Rubber materials, which are used for hydrogen gas seal, can dissolve hydrogen during exposure in high-pressure hydrogen gas. Dissolved hydrogen molecules were detected by solid state 1H NMR of the unfilled vulcanized acrylonitrile butadiene rubber. Two signals were observed at 4.5 ppm and 4.8 ppm, which were assignable to dissolved hydrogen, in the 1H NMR spectrum of NBR after being exposed 100 MPa hydrogen gas for 24 h at room temperature. These signals were shifted from that of gaseous hydrogen molecules. Assignment of the signals was confirmed by quantitative estimation of dissolved hydrogen and peak area of the signals.

Gas, Oil, and Water Production from Grand Valley, Parachute, Rulison, and Mamm Creek Fields in the Piceance Basin, Colorado

USGS Publications Warehouse

Nelson, Philip H.; Santus, Stephen L.

2010-01-01

Gas, oil, and water production data for tight gas reservoirs were compiled from selected wells in western Colorado. These reservoir rocks-the relatively shallow Paleogene Wasatch G sandstone interval in the Parachute and Rulison fields and fluvial sandstones in the deeper Upper Cretaceous Mesaverde Group in the Grand Valley, Parachute, Rulison, and Mamm Creek fields-are characterized by low permeability, low porosity, and the presence of clay minerals in pore space. Production from each well is represented by two samples spaced five years apart, the first sample typically taken two years after production commenced, which was generally in the 1990s. For each producing interval, summary diagrams of oil-versus-gas and water-versus-gas production show fluid production rates, the change in rates during five years, the water-gas and oil-gas ratios, and the fluid type. These diagrams permit well-to-well and field-to-field comparisons. Fields producing water at low rates (water dissolved in gas in the reservoir) can be distinguished from fields producing water at moderate or high rates, and the water-gas ratios are quantified. Dry gas is produced from the Wasatch G interval and wet gas is produced from the Mesaverde Group. Production from the Wasatch G interval is also almost completely free of water, but water production commences with gas production in wells producing from the Mesaverde Group-all of these wells have water-gas ratios exceeding the amount that could exist dissolved in gas at reservoir temperature and pressure. The lack of produced water from the Wasatch G interval is attributed to expansion of the gas accumulation with uplift and erosion. The reported underpressure of the Wasatch G interval is here attributed to hydraulic connection to the atmosphere by outcrops in the Colorado River valley at an elevation lower than that of the gas fields. The amount of reduction of gas production over the five-year time span between the first and second samples is roughly one-half, with median values of second-sample to first-sample gas-production ratios ranging from 0.40 for Rulison-Mesaverde to 0.63 for Rulison-Wasatch G. Commencing with the first sample, the logarithm-of-production rate appears to decline linearly with time in many wells. However, water production is much more erratic as a function of time from an individual well and also from one well to the next within a field. Water production can either decrease or increase with time (from the first to the second sample). In this study, slightly more than half the wells producing from the Mesaverde Group show decreases in water production with time. Plots of water decline versus gas decline show little relation between the two, with only the wells in Rulison field displaying some tendency for water and gas to decline proportionately

Characterizing spatial and temporal variability of dissolved gases in aquatic environments with in situ mass spectrometry.

PubMed

Camilli, Richard; Duryea, Anthony N

2009-07-01

The TETHYS mass spectrometer is intended for long-term in situ observation of dissolved gases and volatile organic compounds in aquatic environments. Its design maintains excellent low mass range sensitivity and stability during long-term operations, enabling characterization of low-frequency variability in many trace dissolved gases. Results are presented from laboratory trials and a 300-h in situ trial in a shallow marine embayment in Massachusetts, U.S.A. This time series consists of over 15000 sample measurements and represents the longest continuous record made by an in situ mass spectrometer in an aquatic environment. These measurements possess sufficient sampling density and duration to apply frequency analysis techniques for study of temporal variability in dissolved gases. Results reveal correlations with specific environmental periodicities. Numerical methods are presented for converting mass spectrometer ion peak ratios to absolute-scale dissolved gas concentrations across wide temperature regimes irrespective of ambient pressure, during vertical water column profiles in a hypoxic deep marine basin off the coast of California, U.S.A. Dissolved oxygen concentration values obtained with the TETHYS instrument indicate close correlation with polarographic oxygen sensor data across the entire depth range. These methods and technology enable observation of aquatic environmental chemical distributions and dynamics at appropriate scales of resolution.

Gas, water, and oil production from Wattenberg field in the Denver Basin, Colorado

USGS Publications Warehouse

Nelson, Philip H.; Santus, Stephen L.

2011-01-01

Gas, oil, and water production data were compiled from selected wells in two tight gas reservoirs-the Codell-Niobrara interval, comprised of the Codell Sandstone Member of the Carlile Shale and the Niobrara Formation; and the Dakota J interval, comprised mostly of the Muddy (J) Sandstone of the Dakota Group; both intervals are of Cretaceous age-in the Wattenberg field in the Denver Basin of Colorado. Production from each well is represented by two samples spaced five years apart, the first sample typically taken two years after production commenced, which generally was in the 1990s. For each producing interval, summary diagrams and tables of oil-versus-gas production and water-versus-gas production are shown with fluid-production rates, the change in production over five years, the water-gas and oil-gas ratios, and the fluid type. These diagrams and tables permit well-to-well and field-to-field comparisons. Fields producing water at low rates (water dissolved in gas in the reservoir) can be distinguished from fields producing water at moderate or high rates, and the water-gas ratios are quantified. The Dakota J interval produces gas on a per-well basis at roughly three times the rate of the Codell-Niobrara interval. After five years of production, gas data from the second samples show that both intervals produce gas, on average, at about one-half the rate as the first sample. Oil-gas ratios in the Codell-Niobrara interval are characteristic of a retrograde gas and are considerably higher than oil-gas ratios in the Dakota J interval, which are characteristic of a wet gas. Water production from both intervals is low, and records in many wells are discontinuous, particularly in the Codell-Niobrara interval. Water-gas ratios are broadly variable, with some of the variability possibly due to the difficulty of measuring small production rates. Most wells for which water is reported have water-gas ratios exceeding the amount that could exist dissolved in gas at reservoir pressure and temperature. The Codell-Niobrara interval is reported to be overpressured (that is, pressure greater than hydrostatic) whereas the underlying Dakota J interval is underpressured (less than hydrostatic), demonstrating a lack of hydraulic communication between the two intervals despite their proximity over a broad geographical area. The underpressuring in the Dakota J interval has been attributed by others to outcropping strata east of the basin. We agree with this interpretation and postulate that the gas accumulation also may contribute to hydraulic isolation from outcrops immediately west of the basin.

Radionuclides, inorganic constituents, organic compounds, and bacteria in water from selected wells and springs from the southern boundary of the Idaho National Engineering Laboratory to the Hagerman area, Idaho, 1992

USGS Publications Warehouse

Bartholomay, R.C.; Edwards, D.D.; Campbell, L.J.

1994-01-01

Dissolved concentrations of radon-222, a naturally occurring radioactive gas, are found in water in Idaho. The U.S. Geological Survey collected water samples for radon-222 analyses from 339 Idaho wells and springs during 1989-91. These water samples were collected as part of ongoing monitoring programs with the Idaho Department of Water Resources and the U.S. Department of Energy. Concentrations of dissolved radon-222 ranged from -58+30 to 5,715+66 picocuries per liter; the mean and median concentrations were 446+35 and 242+25 picocuries per liter, respectively.

Dissolved Pesticide and Organic Carbon Concentrations Detected in Surface Waters, Northern Central Valley, California, 2001-2002

USGS Publications Warehouse

Orlando, James L.; Jacobson, Lisa A.; Kuivila, Kathryn

2004-01-01

Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central Valley of California. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of California. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central Valley of California and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of California Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, California. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon analyzer.

The effects of total dissolved gas on chum salmon fry survival, growth, gas bubble disease, and seawater tolerance

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

Geist, David R.; Linley, Timothy J.; Cullinan, Valerie I.

2013-02-01

Chum salmon Oncorhynchus keta alevin developing in gravel habitats downstream of Bonneville Dam on the Columbia River are exposed to elevated levels of total dissolved gas (TDG) when water is spilled at the dam to move migrating salmon smolts downstream to the Pacific Ocean. Current water quality criteria for the management of dissolved gas in dam tailwaters were developed primarily to protect salmonid smolts and are assumed to be protective of alevin if adequate depth compensation is provided. We studied whether chum salmon alevin exposed to six levels of dissolved gas ranging from 100% to 130% TDG at three developmentmore » periods between hatch and emergence (hereafter early, middle, and late stage) suffered differential mortality, growth, gas bubble disease, or seawater tolerance. Each life stage was exposed for 50 d (early stage), 29 d (middle stage), or 16 d (late stage) beginning at 13, 34, and 37 d post-hatch, respectively, through 50% emergence. The mortality for all stages from exposure to emergence was estimated to be 8% (95% confidence interval (CI) of 4% to 12%) when dissolved gas levels were between 100% and 117% TDG. Mortality significantly increased as dissolved gas levels rose above 117% TDG,; with the lethal concentration that produced 50% mortality (LC50 ) was estimated to be 128.7% TDG (95% CI of 127.2% to 130.2% TDG) in the early and middle stages. By contrast, there was no evidence that dissolved gas level significantly affected growth in any life stage except that the mean wet weight at emergence of early stage fish exposed to 130% TDG was significantly less than the modeled growth of unexposed fish. The proportion of fish afflicted with gas bubble disease increased with increasing gas concentrations and occurred most commonly in the nares and gastrointestinal tract. Early stage fish exhibited higher ratios of filament to lamellar gill chloride cells than late stage fish, and these ratios increased and decreased for early and late stage fish, respectively, as gas levels increased; however, there were no significant differences in mortality between life stages after 96 h in seawater. The study results suggest that current water quality guidelines for the management of dissolved gas appear to offer a conservative level of protection to chum salmon alevin incubating in gravel habitat downstream of Bonneville Dam.« less

X-ray fluorescence measurements of dissolved gas and cavitation

DOE PAGES

Duke, Daniel J.; Kastengren, Alan L.; Swantek, Andrew B.; ...

2016-09-28

The dynamics of dissolved gas and cavitation are strongly coupled, yet these phenomena are difficult to measure in-situ. Both create voids in the fluid that can be difficult to distinguish. In this paper, we present an application of X-ray fluorescence in which liquid density and total noncondensible gas concentration (both dissolved and nucleated) are simultaneously measured. The liquid phase is doped with 400 ppm of a bromine tracer, and dissolved air is removed and substituted with krypton. Fluorescent emission at X-ray wavelengths is simultaneously excited from the Br and Kr with a focused monochromatic X-ray beam from a synchrotron source.more » We measure the flow in a cavitating nozzle 0.5 mm in diameter. From Br fluorescence, total displacement of the liquid is measured. From Kr fluorescence, the mass fraction of both dissolved and nucleated gas is measured. Volumetric displacement of liquid due to both cavitation and gas precipitation can be separated through estimation of the local equilibrium dissolved mass fraction. The uncertainty in the line of sight projected densities of the liquid and gas phases is 4–6 %. The high fluorescence yields and energies of Br and Kr allow small mass fractions of gas to be measured, down to 10 -5, with an uncertainty of 8 %. Finally, these quantitative measurements complement existing optical diagnostic techniques and provide new insight into the diffusion of gas into cavitation bubbles, which can increase their internal density, pressure and lifetimes by orders of magnitude.« less

A simple and sensitive method for the determination of hydroxylamine in fresh-water samples using hypochlorite followed by gas chromatography.

PubMed

Seike, Yasushi; Fukumori, Ryoko; Senga, Yukiko; Oka, Hiroki; Fujinaga, Kaoru; Okumura, Minoru

2004-01-01

A new and simple method for the determination of hydroxylamine in environmental water, such as fresh rivers and lakes using hypochlorite, followed by its gas choromatographic detection, has been developed. A glass vial filled with sample water was sealed by a butyl-rubber stopper and aluminum cap without head-space, and then sodium hypochlorite solution was injected into the vial through a syringe to convert hydroxylamine to nitrous oxide. The head-space in the glass vial was prepared with 99.9% grade N2 using a gas-tight syringe. After the glass vial was shaken for a few minutes, nitrous oxide in the gas-phase was measured by a gas chromatograph with an electron-capture detector. The dissolved nitrous oxide in the liquid-phase was calculated according to the solubility formula. The proposed method was applied to the analysis of fresh-water samples taken from Iu river and Hii river, flowing into brackish Lakes Nakaumi and Shinji, respectively.

Quality-assurance data, comparison to water-quality standards, and site considerations for total dissolved gas and water temperature, lower Columbia River, Oregon and Washington, 2001

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.

2002-03-06

At times in July and August 2001, the total-dissolved-gas probe at Warrendale could not be positioned below the minimum compensation depth because the river was too shallow at that location. Consequently, degassing at probe depth may have occurred, and total dissolved gas may have been larger in locations with greater depths.

Hydraulic Fracturing Fluid Analysis for Regulatory Parameters - A Progress Report

EPA Pesticide Factsheets

This presentation is a progress report on the analysis of Hydraulic Fracturing Fluids for regulatory compounds outlined in the various US EPA methodologies. Fracturing fluids vary significantly in consistency and viscosity prior to fracturing. Due to the nature of the fluids the analytical challenges will have to be addressed. This presentation also outlines the sampling issues associated with the collection of dissolved gas samples.

Lake Roosevelt Fisheries Evaluation Program; Limnological and Fisheries Monitoring, Annual Report 2000.

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

Lee, Chuck; Scofield, Ben; Pavlik, Deanne

2003-03-01

A slightly dryer than normal year yielded flows in Lake Roosevelt that were essentially equal to the past ten year average. Annual mean inflow and outflow were 3,160.3 m3/s and 3,063.4 m3/s respectively. Mean reservoir elevation was 387.2 m above sea level at the Grand Coulee Dam forebay. The forebay elevation was below the mean elevation for a total of 168 days. During the first half of the 2000 forebay elevation changed at a rate of 0.121 m/d and during the last half changed at a rate of 0.208 m/d. The higher rate of elevation change earlier in the yearmore » is due to the drawdown to accommodate spring runoff. Mean annual water retention time was 40 days. Annual mean total dissolved gas was 108%. Total dissolved gas was greatest at upriver locations (110% = US/Canada Border annual mean) and decreased moving toward Grand Coulee Dam (106% = Grand Coulee Dam Forebay annual mean). Total dissolved gas was greatest in May (122% reservoir wide monthly mean). Gas bubble trauma was observed in 16 fish primarily largescale suckers and was low in severity. Reservoir wide mean temperatures were greatest in August (19.5 C) and lowest in January (5.5 C). The Spokane River and Sanpoil River Arms experienced higher temperatures than the mainstem reservoir. Brief stratification was observed at the Sanpoil River shore location in July. Warm water temperatures in the Spokane Arm contributed to low dissolved oxygen concentrations in August (2.6 mg/L at 33 m). However, decomposition of summer algal biomass was likely the main cause of depressed dissolved oxygen concentrations. Otherwise, dissolved oxygen profiles were relatively uniform throughout the water column across other sampling locations. Annual mean Secchi depth throughout the reservoir was 5.7 m. Nutrient concentrations were generally low, however, annual mean total phosphorus (0.016 mg/L) was in the mesotrophic range. Annual mean total nitrogen was in the meso-oligotrophic range. Total nitrogen to total phosphorus ratios were large (31:1 annual mean) likely indicating phosphorus limitations to phytoplankton.« less

Baseline assessment of groundwater quality in Pike County, Pennsylvania, 2015

USGS Publications Warehouse

Senior, Lisa A.; Cravotta, Charles A.

2017-12-29

The Devonian-age Marcellus Shale and the Ordovician-age Utica Shale, which have the potential for natural gas development, underlie Pike County and neighboring counties in northeastern Pennsylvania. In 2015, the U.S. Geological Survey, in cooperation with the Pike County Conservation District, conducted a study that expanded on a previous more limited 2012 study to assess baseline shallow groundwater quality in bedrock aquifers in Pike County prior to possible extensive shale-gas development. Seventy-nine water wells ranging in depths from 80 to 610 feet were sampled during June through September 2015 to provide data on the presence of methane and other aspects of existing groundwater quality in the various bedrock geologic units throughout the county, including concentrations of inorganic constituents commonly present at low values in shallow, fresh groundwater but elevated in brines associated with fluids extracted from geologic formations during shale-gas development. All groundwater samples collected in 2015 were analyzed for bacteria, dissolved and total major ions, nutrients, selected dissolved and total inorganic trace constituents (including metals and other elements), radon-222, gross alpha- and gross beta-particle activity, dissolved gases (methane, ethane, and propane), and, if sufficient methane was present, the isotopic composition of methane. Additionally, samples from 20 wells distributed throughout the county were analyzed for selected man-made volatile organic compounds, and samples from 13 wells where waters had detectable gross alpha activity were analyzed for radium-226 on the basis of relatively elevated gross alpha-particle activity.Results of the 2015 study show that groundwater quality generally met most drinking-water standards for constituents and properties included in analyses, but groundwater samples from some wells had one or more constituents or properties, including arsenic, iron, manganese, pH, bacteria, sodium, chloride, sulfate, total dissolved solids, and radon-222, that did not meet (commonly termed failed or exceeded) primary or secondary maximum contaminant levels (MCLs) or Health Advisories (HA) for drinking water. Except for iron, dissolved and total concentrations of major ions and most trace constituents generally were similar. Only 1 of 79 well-water samples had any constituent that exceeded a MCL, with an arsenic concentration of about 30 micrograms per liter (µg/L) that was higher than the MCL of 10 µg/L. However, total arsenic concentrations were higher than the HA of 2 µg/L in samples from another 12 of 79 wells (about 15 percent). Secondary maximum contaminant levels (SMCLs) were exceeded most frequently by pH and concentrations of iron and manganese. The pH was outside of the SMCL range of 6.5–8.5 in samples from 24 of 79 wells (30 percent), ranging from 5.5 to 9.2; more samples had pH values less than 6.5 than had pH values greater than 8.5. Total iron concentrations typically were much greater than dissolved iron concentrations, indicating substantial presence of iron in particulate phase, and exceeded the SMCL of 300 µg/L more often [35 of 79 samples (44 percent)] than dissolved iron concentrations [samples from 8 of 79 wells (10 percent)]. Total manganese concentrations exceeded the SMCL of 50 µg/L in samples from 31 of 79 wells (39 percent) and the HA of 300 µg/L in samples from 13 of 79 wells (about 16 percent). A few (1–2) samples had concentrations of sodium, chloride, sulfate, or TDS higher than the SMCLs of 60, 250, 250, and 500 mg/L, respectively. However, dissolved sodium concentrations were higher than the HA of 20 mg/L in samples from 15 of 79 wells (nearly 20 percent). Total coliform bacteria were detected in samples from 25 of 79 wells (32 percent) but Escherichia coli were not detected in any sample. Radon-222 activities ranged from 11 to 5,100 picocuries per liter (pCi/L), with a median of 1,440 pCi/L, and exceeded the proposed and the alternate proposed drinking-water standards of 300 and 4,000 pCi/L, respectively, in samples from 60 of 79 wells (75 percent) and in samples from 2 of 79 wells (3 percent), respectively.Groundwater samples from all wells were analyzed for dissolved methane by one contract laboratory that determined water from 19 of the 79 wells (24 percent) had concentrations of methane greater than the reporting level of 0.010 milligrams per liter (mg/L) with a maximum methane concentration of 2.5 mg/L. Methane concentrations in 18 replicate samples submitted to a second laboratory for dissolved gas and isotopic analysis generally were higher by as much as a factor of 2.7 from those determined by the first laboratory, indicating potential bias related to combined sampling and analytical methods, and therefore, caution needs to be used when comparing methane results determined by different methods. The isotopic composition of methane in 9 of 10 samples with sufficient dissolved methane (about 0.3 mg/L) for isotopic analysis is consistent with values reported for methane of microbial origin produced through carbon dioxide reduction; an isotopic shift in 1 or 2 samples may indicate subsequent methane oxidation. The low concentrations of ethane relative to methane in these samples further indicate that the methane may be of microbial origin. Groundwater samples with relatively elevated methane concentrations (near or greater than 0.3 mg/L) also had chemical compositions that differed in some respects from groundwater with relatively low methane concentrations (less than 0.3 mg/L) by having higher pH (greater than 8) and higher concentrations of sodium, lithium, boron, fluoride, arsenic, and bromide and chloride/bromide ratios indicative of mixing with a small amount of brine of probable natural occurrence.The spatial distribution of groundwater compositions differs by topographic setting and lithology and generally shows that (1) relatively dilute, slightly acidic, oxygenated, calcium-carbonate type waters tend to occur in the uplands underlain by the undivided Poplar Gap and Packerton members of the Catskill Formation in southwestern Pike County; (2) waters of near neutral pH with the highest amounts of hardness (calcium and magnesium) generally occur in areas of intermediate altitudes underlain by other members of the Catskill Formation; and (3) waters with pH values greater than 8, low oxygen concentrations, and the highest arsenic, sodium, lithium, bromide, and methane concentrations can be present in deep wells in uplands but most frequently occur in stream valleys, especially at low altitudes (less than about 1,200 feet above North American Vertical Datum of 1988) where groundwater may be discharging regionally, such as to the Delaware River in northern and eastern Pike County. Thus, the baseline assessment of groundwater quality in Pike County prior to gas-well development shows that shallow (less than about 1,000 feet deep) groundwater generally meets primary drinking-water standards for inorganic constituents but varies spatially, with methane and some constituents present in high concentrations in brine (and connate waters from gas and oil reservoirs) present at low to moderate concentrations in some parts of Pike County.

Sensitive ion detection device and method for analysis of compounds as vapors in gases

DOEpatents

Denton, M. Bonner; Sperline, Roger P.

2015-09-15

An ion mobility spectrometer (IMS) for the detection of trace gaseous molecular compounds dissolved or suspended in a carrier gas, particularly in ambient air, without preconcentration or the trapping of analyte particles. The IMS of the invention comprises an ionization volume of greater than 5 cm.sup.3 and preferably greater than 100 cm.sup.3. The larger size ionizers of this invention enable analysis of trace (<1 ppb) of sample compounds in the gas phase. To facilitate efficient ion motion through the large volume ionization and reaction regions of the IMS, an electric field gradient can be provided in the ionization region or in both the ionization and reaction regions. The systems can be implemented with radioactive ionization sources, corona discharge ion sources or ions can be formed by photoionization. In specific embodiments, particularly when the sample gas is ambient air, the sample gas is heater prior to entry into the instrument, the instrument is run at temperatures above ambient, and the instrument can be heated by contact with heated sample gas exiting the instrument.

Sensitive ion detection device and method for analysis of compounds as vapors in gases

DOEpatents

Denton, M. Bonner; Sperline, Roger P

2014-02-18

An ion mobility spectrometer (IMS) for the detection of trace gaseous molecular compounds dissolved or suspended in a carrier gas, particularly in ambient air, without preconcentration or the trapping of analyte particles. The IMS of the invention comprises an ionization volume of greater than 5 cm.sup.3 and preferably greater than 100 cm.sup.3. The larger size ionizers of this invention enable analysis of trace (<1 ppb) of sample compounds in the gas phase. To facilitate efficient ion motion through the large volume ionization and reaction regions of the IMS, an electric field gradient can be provided in the ionization region or in both the ionization and reaction regions. The systems can be implemented with radioactive ionization sources, corona discharge ion sources or ions can be formed by photoionization. In specific embodiments, particularly when the sample gas is ambient air, the sample gas is heater prior to entry into the instrument, the instrument is run at temperatures above ambient, and the instrument can be heated by contact with heated sample gas exiting the instrument.

Tritium trick

NASA Technical Reports Server (NTRS)

Green, W. V.; Zukas, E. G.; Eash, D. T.

1971-01-01

Large controlled amounts of helium in uniform concentration in thick samples can be obtained through the radioactive decay of dissolved tritium gas to He3. The term, tritium trick, applies to the case when helium, added by this method, is used to simulate (n,alpha) production of helium in simulated hard flux radiation damage studies.

INTEGRATED AND REAL-TIME DIFFUSION DENUDER SAMPLE FOR PM2.5. (R825367)

EPA Science Inventory

Abstract

Particulate matter (PM) is a complex mixture of stable condensed phases, adsorbed or dissolved gases, and semi-volatile materials, i.e. compounds that transfer between the gas and condensed phases. Fine particles in both rural and urban environments contain su...

Feasibility of measuring dissolved carbon dioxide based on head space partial pressures

USGS Publications Warehouse

Watten, B.J.; Boyd, C.E.; Schwartz, M.F.; Summerfelt, S.T.; Brazil, B.L.

2004-01-01

We describe an instrument prototype that measures dissolved carbon dioxide (DC) without need for standard wetted probe membranes or titration. DC is calculated using Henry's Law, water temperature, and the steady-state partial pressure of carbon dioxide that develops within the instrument's vertical gas-liquid contacting chamber. Gas-phase partial pressures were determined with either an infrared detector (ID) or by measuring voltage developed by a pH electrode immersed in an isolated sodium carbonate solution (SC) sparged with recirculated head space gas. Calculated DC concentrations were compared with those obtained by titration over a range of DC (2, 4, 8, 12, 16, 20, 24, and 28mg/l), total alkalinity (35, 120, and 250mg/l as CaCO3), total dissolved gas pressure (-178 to 120 mmHg), and dissolved oxygen concentrations (7, 14, and 18 mg/l). Statistically significant (P < 0.001) correlations were established between head space (ID) and titrimetrically determined DC concentrations (R2 = 0.987-0.999, N = 96). Millivolt and titrimetric values from the SC solution tests were also correlated (P < 0.001, R 2 = 0.997, N = 16). The absolute and relative error associated with the use of the ID and SC solution averaged 0.9mg/l DC and 7.0% and 0.6 mg/l DC and 9.6%, respectively. The precision of DC estimates established in a second test series was good; coefficients of variation (100(SD/mean)) for the head space (ID) and titration analyses were 0.99% and 1.7%. Precision of the SC solution method was 1.3%. In a third test series, a single ID was coupled with four replicate head space units so as to permit sequential monitoring (15 min intervals) of a common water source. Here, appropriate gas samples were secured using a series of solenoid valves (1.6 mm bore) activated by a time-based controller. This system configuration reduced the capital cost per sample site from US$ 2695 to 876. Absolute error averaged 2.9, 3.1, 3.7, and 2.7 mg/ l for replicates 1-4 (N = 36) during a 21-day test period (DC range, 36-40 mg/l). The ID meter was then modified so as to provide for DO as well as DC measurements across components of an intensive fish production system. ?? 2003 Elsevier B.V. All rights reserved.

Geochemistry of thermal water from selected wells, Boise, Idaho

USGS Publications Warehouse

Mariner, R.H.; Young, H.W.; Parliman, D.J.; Evans, William C.

1989-01-01

Samples of thermal water from selected wells in the Boise area were analyzed for chemical composition; stable isotopes of hydrogen, oxygen, and dissolved carbon; radioactive carbon; and dissolved-gas concentrations. Chemically, the waters are virtually identical to those of the adjacent Idaho batholith. Isotopically, the thermal waters are more depleted in deuterium and oxygen-18 than coldwater springs in the presumed recharge area. Chemical and isotopic data indicate the presence of two separate geothermal systems. Radioactive carbon and dissolved helium concentrations are interpreted to indicate recharge during the Pleistocene. Hot water in or southeast of Boise probably recharged 20,000 to 30,000 years ago, and warm water 2.5 miles northwest of Boise probably recharged at least 15,000 years ago.

A Rapid, Low-Cost Method to Determine Travel Times at Managed Aquifer Recharge Operations Using Noble Gas Tracers

NASA Astrophysics Data System (ADS)

Moran, J. E.; Visser, A.; Singleton, M. J.; Esser, B. K.; Halliwell, M.; Hillegonds, D. J.

2012-12-01

Managed aquifer recharge is a key component for the sustainable use of surface water and groundwater in the arid western U.S. When recycled water is a recharge water source, subsurface residence time, required for bacteria and virus deactivation, is best verified by application of an extrinsic tracer. Desirable tracer properties include: no real or perceived health risk, inexpensive even for a large volume of tagged water, large dynamic range, efficient introduction, convenient sampling methods, and rapid, low-cost analysis. We have developed and tested a dissolved noble gas tracer technique ideally suited for tracing large water volumes at managed aquifer recharge facilities. In an application of the method at a water district's facilities in the San Francisco Bay area, Xenon was introduced into a 106 m3 pond over a period of 7 days using a 300 m length of gas-permeable silicone tubing. Samples from the pond, near-field shallow monitoring wells, and production wells about 400 m from the recharge pond were analyzed for dissolved Xe by noble gas membrane inlet mass spectrometry (NGMIMS). The NGMIMS uses a syringe pump, gas-permeable membrane inlet, and quadrupole residual gas analyzer for measurement of noble gas concentrations. Samples are collected in VOA vials, and analysis can be carried out in real-time, with a measurement uncertainty of about 5% for Xe. Tracer first appeared in a production well 136 days after starting the tracer introduction at 0.7% (C/C0) of the peak pond xenon concentration. The cost of the tracer is about US650/106 m3 water, and the NGMIMS was assembled with parts totaling approximately US50,000, making application of the tracer method feasible for most managed aquifer recharge projects. This project is part of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program.

Gas, Oil, and Water Production from Jonah, Pinedale, Greater Wamsutter, and Stagecoach Draw Fields in the Greater Green River Basin, Wyoming

USGS Publications Warehouse

Nelson, Philip H.; Ewald, Shauna M.; Santus, Stephen L.; Trainor, Patrick K.

2010-01-01

Gas, oil, and water production data were compiled from selected wells in four gas fields in rocks of Late Cretaceous age in southwestern Wyoming. This study is one of a series of reports examining fluid production from tight-gas reservoirs, which are characterized by low permeability, low porosity, and the presence of clay minerals in pore space. Production from each well is represented by two samples spaced five years apart, the first sample typically taken two years after commencement of production. For each producing interval, summary diagrams of oil versus gas and water versus gas production show fluid production rates, the change in rates during five years, the water-gas and oil-gas ratios, and the fluid type. These diagrams permit well-to-well and field-to-field comparisons. Fields producing water at low rates (water dissolved in gas in the reservoir) can be distinguished from fields producing water at moderate or high rates, and the water-gas ratios are quantified. The ranges of first-sample gas rates in Pinedale field and Jonah field are quite similar, and the average gas production rate for the second sample, taken five years later, is about one-half that of the first sample for both fields. Water rates are generally substantially higher in Pinedale than in Jonah, and water-gas ratios in Pinedale are roughly a factor of ten greater in Pinedale than in Jonah. Gas and water production rates from each field are fairly well grouped, indicating that Pinedale and Jonah fields are fairly cohesive gas-water systems. Pinedale field appears to be remarkably uniform in its flow behavior with time. Jonah field, which is internally faulted, exhibits a small spread in first-sample production rates. In the Greater Wamsutter field, gas production from the upper part of the Almond Formation is greater than from the main part of the Almond. Some wells in the main and the combined (upper and main parts) Almond show increases in water production with time, whereas increases in water production are rare in the upper part of the Almond, and a higher percentage of wells in the upper part of the Almond show water decreasing at the same rate as gas than in the main or combined parts of the Almond. In Stagecoach Draw field, the gas production rate after five years is about one-fourth that of the first sample, whereas in Pinedale, Jonah, and Greater Wamsutter fields, the production rate after five years is about one-half that of the first sample. The more rapid gas decline rate seems to be the outstanding feature distinguishing Stagecoach Draw field, which is characterized as a conventional field, from Pinedale, Jonah, and Greater Wamsutter fields, which are generally characterized as tight-gas accumulations. Oil-gas ratios are fairly consistent within Jonah, Pinedale, and Stagecoach Draw fields, suggesting similar chemical composition and pressure-temperature conditions within each field, and are less than the 20 bbl/mmcf upper limit for wet gas. However, oil-gas ratios vary considerably from one area to another in the Greater Wamsutter field, demonstrating a lack of commonality in either chemistry or pressure-temperature conditions among the six areas. In all wells in all four fields examined here, water production commences with gas production-there are no examples of wells with water-free production and no examples where water production commences after first-sample gas production. The fraction of records with water production higher in the second sample than in the first sample varies from field to field, with Pinedale field showing the lowest percentage of such cases and Jonah field showing the most. Most wells have water-gas ratios exceeding the amount that could exist dissolved in gas at reservoir pressure and temperature.

Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009

USGS Publications Warehouse

McMahon, P.B.; Thomas, J.C.; Hunt, A.G.

2011-01-01

Previous water-quality assessments reported elevated concentrations of nitrate and methane in water from domestic wells screened in shallow zones of the Wasatch Formation, Garfield County, Colorado. In 2009, the U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, analyzed samples collected from 26 domestic wells for a diverse set of geochemical tracers for the purpose of determining sources and sinks of nitrate and methane in groundwater from the Wasatch Formation. Nitrate concentrations ranged from less than 0.04 to 6.74 milligrams per liter as nitrogen (mg/L as N) and were significantly lower in water samples with dissolved-oxygen concentrations less than 0.5 mg/L than in samples with dissolved-oxygen concentrations greater than or equal to 0.5 mg/L. Chloride/bromide mass ratios and tracers of groundwater age (tritium, chlorofluorocarbons, and sulfur hexafluoride) indicate that septic-system effluent or animal waste was a source of nitrate in some young groundwater (less than 50 years), although other sources such as fertilizer also may have contributed nitrate to the groundwater. Nitrate and nitrogen gas (N2) concentrations indicate that denitrification was the primary sink for nitrate in anoxic groundwater, removing 99 percent of the original nitrate content in some samples that had nitrate concentrations greater than 10 mg/L as N at the time of recharge. Methane concentrations ranged from less than 0.0005 to 32.5 mg/L and were significantly higher in water samples with dissolved-oxygen concentrations less than 0.5 mg/L than in samples with dissolved-oxygen concentrations greater than or equal to 0.5 mg/L. High methane concentrations (greater than 1 mg/L) in some samples were biogenic in origin and appeared to be derived from a relatively deep source on the basis of helium concentrations and isotopic data. One such sample had water-isotopic and major-ion compositions similar to that of produced water from the underlying Mesaverde Group, which was the primary natural-gas producing interval in the study area. Methane in the Mesaverde Group was largely thermogenic in origin so biogenic methane in the sample probably was derived from deeper zones in the Wasatch Formation. The primary methane sink in the aquifer appeared to be methane oxidation on the basis of dissolved-oxygen and methane concentrations and methane isotopic data. The diverse data sets used in this study enhance previous water-quality assessments by providing new and more complete insights into the sources and sinks of nitrate and methane in groundwater. Field measurements of dissolved oxygen in groundwater were useful indicators of the Wasatch Formation's vulnerability to nitrate and methane contamination or enrichment. Results from this study also provide new evidence for the movement of water, ions, and gases into the shallow Wasatch Formation from sources such as the Mesaverde Group and deeper Wasatch Formation.

Simple and accurate method for determining dissolved inorganic carbon in environmental water by reaction headspace gas chromatography.

PubMed

Xie, Wei-Qi; Gong, Yi-Xian; Yu, Kong-Xian

2018-03-01

We investigate a simple and accurate method for quantitatively analyzing dissolved inorganic carbon in environmental water by reaction headspace gas chromatography. The neutralization reaction between the inorganic carbon species (i.e. bicarbonate ions and carbonate ions) in environmental water and hydrochloric acid is carried out in a sealed headspace vial, and the carbon dioxide formed from the neutralization reaction, the self-decomposition of carbonic acid, and dissolved carbon dioxide in environmental water is then analyzed by headspace gas chromatography. The data show that the headspace gas chromatography method has good precision (relative standard deviation ≤ 1.63%) and accuracy (relative differences ≤ 5.81% compared with the coulometric titration technique). The headspace gas chromatography method is simple, reliable, and can be well applied in the dissolved inorganic carbon detection in environmental water. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methodologies for extraction of dissolved inorganic carbon for stable carbon isotope studies : evaluation and alternatives

USGS Publications Warehouse

Hassan, Afifa Afifi

1982-01-01

The gas evolution and the strontium carbonate precipitation techniques to extract dissolved inorganic carbon (DIC) for stable carbon isotope analysis were investigated. Theoretical considerations, involving thermodynamic calculations and computer simulation pointed out several possible sources of error in delta carbon-13 measurements of the DIC and demonstrated the need for experimental evaluation of the magnitude of the error. An alternative analytical technique, equilibration with out-gassed vapor phase, is proposed. The experimental studies revealed that delta carbon-13 of the DIC extracted from a 0.01 molar NaHC03 solution by both techniques agreed within 0.1 per mil with the delta carbon-13 of the DIC extracted by the precipitation technique, and an increase of only 0.27 per mil in that extracted by the gas evolution technique. The efficiency of extraction of DIC decreased with sulfate concentration in the precipitation technique but was independent of sulfate concentration in the gas evolution technique. Both the precipitation and gas evolution technique were found to be satisfactory for extraction of DIC from different kinds of natural water for stable carbon isotope analysis, provided appropriate precautions are observed in handling the samples. For example, it was found that diffusion of atmospheric carbon dioxide does alter the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the precipitation technique; hot manganese dioxide purification changes the delta carbon-13 of carbon dioxide. (USGS)

Feasible metabolisms in high pH springs of the Philippines

PubMed Central

Cardace, Dawn; Meyer-Dombard, D'Arcy R.; Woycheese, Kristin M.; Arcilla, Carlo A.

2015-01-01

A field campaign targeting high pH, H2-, and CH4-emitting serpentinite-associated springs in the Zambales and Palawan Ophiolites of the Philippines was conducted in 2012-2013, and enabled description of several springs sourced in altered pillow basalts, gabbros, and peridotites. We combine field observations of pH, temperature, conductivity, dissolved oxygen, and oxidation-reduction potential with analyses of major ions, dissolved inorganic carbon, dissolved organic carbon, and dissolved gas phases in order to model the activities of selected phases important to microbial metabolism, and to rank feasible metabolic reactions based on energy yield. We document changing geochemical inventories in these springs between sampling years, and examine how the environment supports or prevents the function of certain microbial metabolisms. In all, this geochemistry-based assessment of feasible metabolisms indicates methane cycling, hydrogen oxidation, some iron and sulfur metabolisms, and ammonia oxidation are feasible reactions in this continental site of serpentinization. PMID:25713561

Feasible metabolisms in high pH springs of the Philippines.

PubMed

Cardace, Dawn; Meyer-Dombard, D'Arcy R; Woycheese, Kristin M; Arcilla, Carlo A

2015-01-01

A field campaign targeting high pH, H2-, and CH4-emitting serpentinite-associated springs in the Zambales and Palawan Ophiolites of the Philippines was conducted in 2012-2013, and enabled description of several springs sourced in altered pillow basalts, gabbros, and peridotites. We combine field observations of pH, temperature, conductivity, dissolved oxygen, and oxidation-reduction potential with analyses of major ions, dissolved inorganic carbon, dissolved organic carbon, and dissolved gas phases in order to model the activities of selected phases important to microbial metabolism, and to rank feasible metabolic reactions based on energy yield. We document changing geochemical inventories in these springs between sampling years, and examine how the environment supports or prevents the function of certain microbial metabolisms. In all, this geochemistry-based assessment of feasible metabolisms indicates methane cycling, hydrogen oxidation, some iron and sulfur metabolisms, and ammonia oxidation are feasible reactions in this continental site of serpentinization.

Practical considerations for measuring hydrogen concentrations in groundwater

USGS Publications Warehouse

Chapelle, F.H.; Vroblesky, D.A.; Woodward, J.C.; Lovley, D.R.

1997-01-01

Several practical considerations for measuring concentrations of dissolved molecular hydrogen (H2) in groundwater including 1 sampling methods 2 pumping methods and (3) effects of well casing materials were evaluated. Three different sampling methodologies (a downhole sampler, a gas- stripping method, and a diffusion sampler) were compared. The downhole sampler and gas-stripping methods gave similar results when applied to the same wells, the other hand, appeared to The diffusion sampler, on overestimate H2 concentrations relative to the downhole sampler. Of these methods, the gas-stripping method is better suited to field conditions because it is faster (~ 30 min for a single analysis as opposed to 2 h for the downhole sampler or 8 h for the diffusion sampler), the analysis is easier (less sample manipulation is required), and the data computations are more straightforward (H2 concentrations need not be corrected for water sample volume). Measurement of H2 using the gas-stripping method can be affected by different pumping equipment. Peristaltic, piston, and bladder pumps all gave similar results when applied to water produced from the same well. It was observed, however, that peristaltic-pumped water (which draws water under a negative pressure) enhanced the gas-stripping process and equilibrated slightly faster than either piston or bladder pumps (which push water under a positive pressure). A direct current(dc) electrically driven submersible pump was observed to produce H2 and was not suitable for measuring H2 in groundwater. Measurements from two field sites indicate that iron or steel well casings, produce H2, which masks H2 concentrations in groundwater. PVC-cased wells or wells cased with other materials that do not produce H2 are necessary for measuring H2 concentrations in groundwater.Several practical considerations for measuring concentrations of dissolved molecular hydrogen in groundwater including sampling methods, pumping methods, and effects of well casing materials were evaluated. The downhole sampler and gas-stripping methods gave similar results when applied to the same wells. The diffusional sampler appears to overestimate H2 concentrations relative to the downhole sampler. Gas-stripping method is better for a single analysis and the data computations are more straightforward. Measurement of H2 using the gas-stripping method can be affected by different pumping equipment.

A new device for continuous monitoring the CO2 dissolved in water

NASA Astrophysics Data System (ADS)

de Gregorio, S.; Camarda, M.; Cappuzzo, S.; Giudice, G.; Gurrieri, S.; Longo, M.

2009-04-01

The measurements of dissolved CO2 in water are common elements of industrial processes and scientific research. In order to perform gas dissolved measurements is required to separate the dissolved gaseous phase from water. We developed a new device able to separate the gases phase directly in situ and well suitable for continuous measuring the CO2 dissolved in water. The device is made by a probe of a polytetrafluorethylene (PTFE) tube connected to an I.R. spectrophotometer (I.R.) and a pump. The PTFE is a polymeric semi-permeable membrane and allows the permeation of gas in the system. Hence, this part of the device is dipped in water in order to equilibrate the probe headspace with the dissolved gases. The partial pressure of the gas i in the headspace at equilibrium (Pi) follows the Henry's law: Pi=Hi•Ci, where Hi is the Henry's constant and Ci is the dissolved concentration of gas i. After the equilibrium is achieved, the partial pressure of CO2 inside the tube is equal to the partial pressure of dissolved CO2. The concentration of CO2 is measured by the I.R. connected to the tube. The gas is moved from the tube headspace to the I.R. by using the pump. In order to test the device and assess the best operating condition, several experimental were performed in laboratory. All the test were executed in a special apparatus where was feasible to create controlled atmospheres. Afterward the device has been placed in a draining tunnel sited in the Mt. Etna Volcano edifice (Italy). The monitored groundwater intercepts the Pernicana Fault, along which degassing phenomena are often observed. The values recorded by the station result in agreement with monthly directly measurements of dissolved CO2 partial pressure.

Geopressured-geothermal test of the EDNA Delcambre No. 1 well, Tigre Lagoon Field, Vermilion Parish, Louisiana: Analysis of water and dissolved natural gas: Final report

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

Hankind, B.E.; Karkalits, O.C.

1978-09-01

The presence of large volumes of hot water (250-425 F) containing dissolved natural gas in the Gulf of Mexico coastal areas at depths of 5,000 to 25,000 feet (the geopressured zone) has been known for several years. Because natural gas and oil from conventional production methods were relatively inexpensive prior to 1973, and because foreign oil was readily available, no economic incentive existed for developing this resource. With the oil embargo and the resulting rapid escalation in prices of oil and gas since 1973, a new urgency exists for examining the economic potential of the geopressured-geothermal resource. The main objectivemore » of the research reported here was to determine the volume of gas dissolved in the geopressured water, as well as the qualitative and quantitative composition of the water and the dissolved gas. A further objective was to use an existing shut-in gas well so that drilling time and the attendant costs could be avoided.« less

Shallow groundwater quality and geochemistry in the Fayetteville Shale gas-production area, north-central Arkansas, 2011

USGS Publications Warehouse

Kresse, Timothy M.; Warner, Nathaniel R.; Hays, Phillip D.; Down, Adrian; Vengosh, Avner; Jackson, Robert B.

2012-01-01

The Mississippian Fayetteville Shale serves as an unconventional gas reservoir across north-central Arkansas, ranging in thickness from approximately 50 to 550 feet and varying in depth from approximately 1,500 to 6,500 feet below the ground surface. Primary permeability in the Fayetteville Shale is severely limited, and successful extraction of the gas reservoir is the result of advances in horizontal drilling techniques and hydraulic fracturing to enhance and develop secondary fracture porosity and permeability. Drilling and production of gas wells began in 2004, with a steady increase in production thereafter. As of April 2012, approximately 4,000 producing wells had been completed in the Fayetteville Shale. In Van Buren and Faulkner Counties, 127 domestic water wells were sampled and analyzed for major ions and trace metals, with a subset of the samples analyzed for methane and carbon isotopes to describe general water quality and geochemistry and to investigate the potential effects of gas-production activities on shallow groundwater in the study area. Water-quality analyses from this study were compared to historical (pregas development) shallow groundwater quality collected in the gas-production area. An additional comparison was made using analyses from this study of groundwater quality in similar geologic and topographic areas for well sites less than and greater than 2 miles from active gas-production wells. Chloride concentrations for the 127 groundwater samples collected for this study ranged from approximately 1.0 milligram per liter (mg/L) to 70 mg/L, with a median concentration of 3.7 mg/L, as compared to maximum and median concentrations for the historical data of 378 mg/L and 20 mg/L, respectively. Statistical analysis of the data sets revealed statistically larger chloride concentrations (p-value <0.001) in the historical data compared to data collected for this study. Chloride serves as an important indicator parameter based on its conservative transport characteristics and relatively elevated concentrations in production waters associated with gas extraction activities. Major ions and trace metals additionally had lower concentrations in data gathered for this study than in the historical analyses. Additionally, no statistical difference existed between chloride concentrations from water-quality data collected for this study from 94 wells located less than 2 miles from a gas-production well and 33 wells located 2 miles or more from a gas-production well; a Wilcoxon rank-sum test showed a p-value of 0.71. Major ion chemistry was investigated to understand the effects of geochemical and reduction-oxidation (redox) processes on the shallow groundwater in the study area along a continuum of increased rock-water interaction represented by increases in dissolved solids concentration. Groundwater in sandstone formations is represented by a low dissolved solids concentration (less than 30 mg/L) and slightly acidic water type. Shallow shale aquifers were represented by dissolved solids concentrations ranging upward to 686 mg/L, and water types evolving from a dominantly mixed-bicarbonate and calcium-bicarbonate to a strongly sodium-bicarbonate water type. Methane concentration and carbon isotopic composition were analyzed in 51 of the 127 samples collected for this study. Methane occurred above a detection limit of 0.0002 mg/L in 32 of the 51 samples, with concentrations ranging upward to 28.5 mg/L. Seven samples had methane concentrations greater than or equal to 0.5 mg/L. The carbon isotopic composition of these higher concentration samples, including the highest concentration of 28.5 mg/L, shows the methane was likely biogenic in origin with carbon isotope ratio values ranging from -57.6 to -74.7 per mil. Methane concentrations increased with increases in dissolved solids concentrations, indicating more strongly reducing conditions with increasing rock-water interaction in the aquifer. As such, groundwater-quality data collected for this study indicate that groundwater chemistry in the shallow aquifer system in the study area is a result of natural processes, beginning with recharge of dilute atmospheric precipitation and evolution of observed groundwater chemistry through rock-water interaction and redox processes.

Supersaturation of Dissolved Hydrogen and Methane in Rumen of Tibetan Sheep

PubMed Central

Wang, Min; Ungerfeld, Emilio M.; Wang, Rong; Zhou, Chuan She; Basang, Zhu Zha; Ao, Si Man; Tan, Zhi Liang

2016-01-01

Hydrogen (H2) is an essential substrate for methanogens to produce methane (CH4), and also influences pathways of volatile fatty acids (VFA) production in the rumen. Dissolved H2 (H2 (aq)) is the form of H2 available to microbes, and dissolved CH4 (CH4 (aq)) is important for indicating methanogens activity. Rumen H2 (aq) concentration has been estimated by assuming equilibrium with headspace gaseous H2 (H2 (g)) concentration using Henry's law, and has also been directly measured in the liquid phase in some in vitro and in vivo experiments. In this in vivo study, H2 (aq) and CH4 (aq) concentration measured directly in rumen fluid and their corresponding concentrations estimated from their gaseous phase concentrations, were compared to investigate the existence of equilibrium between the gas and liquid phases. Twenty-four Tibetan sheep were randomly assigned to two mixed diets containing the same concentrate mixed with oat grass (OG diet) or barley straw (BS diet). Rumen gaseous phase and contents were sampled using rumenocentesis and oral stomach tubing, respectively. Rumen H2 (aq) and CH4 (aq) concentration and VFA profile differed between sheep fed OG and BS diets. Measured H2 (aq) and CH4 (aq) concentration were greater than H2 (aq) and CH4 (aq) concentrations estimated using gas concentrations, indicating lack of equilibrium between gas and liquid phase and supersaturation of H2 and CH4 in rumen fluid. As a consequence, Gibbs energy changes (ΔG) estimated for various metabolic pathways were different when calculated using dissolved gases concentrations directly measured and when using dissolved gases concentrations assuming equilibrium with the gaseous phase. Dissolved CH4, but not CH4 (g), was positively correlated with H2 (aq). Both H2 (aq) and H2 (g) concentrations were positively correlated with the molar percentage of butyrate and negatively correlated with the molar percentage of acetate. In summary, rumen fluid was supersaturated with both H2 and CH4, and H2 (aq) was closely associated with the VFA profile and CH4 (aq) concentration. The assumption of equilibrium between dissolved gases and gaseous phase affected ΔG estimation. PMID:27379028

An evaluation of water quality in private drinking water wells near natural gas extraction sites in the Barnett Shale formation.

PubMed

Fontenot, Brian E; Hunt, Laura R; Hildenbrand, Zacariah L; Carlton, Doug D; Oka, Hyppolite; Walton, Jayme L; Hopkins, Dan; Osorio, Alexandra; Bjorndal, Bryan; Hu, Qinhong H; Schug, Kevin A

2013-09-03

Natural gas has become a leading source of alternative energy with the advent of techniques to economically extract gas reserves from deep shale formations. Here, we present an assessment of private well water quality in aquifers overlying the Barnett Shale formation of North Texas. We evaluated samples from 100 private drinking water wells using analytical chemistry techniques. Analyses revealed that arsenic, selenium, strontium and total dissolved solids (TDS) exceeded the Environmental Protection Agency's Drinking Water Maximum Contaminant Limit (MCL) in some samples from private water wells located within 3 km of active natural gas wells. Lower levels of arsenic, selenium, strontium, and barium were detected at reference sites outside the Barnett Shale region as well as sites within the Barnett Shale region located more than 3 km from active natural gas wells. Methanol and ethanol were also detected in 29% of samples. Samples exceeding MCL levels were randomly distributed within areas of active natural gas extraction, and the spatial patterns in our data suggest that elevated constituent levels could be due to a variety of factors including mobilization of natural constituents, hydrogeochemical changes from lowering of the water table, or industrial accidents such as faulty gas well casings.

Visualization of gas dissolution following upward gas migration in porous media: Technique and implications for stray gas

NASA Astrophysics Data System (ADS)

Van De Ven, C. J. C.; Mumford, Kevin G.

2018-05-01

The study of gas-water mass transfer in porous media is important in many applications, including unconventional resource extraction, carbon storage, deep geological waste storage, and remediation of contaminated groundwater, all of which rely on an understanding of the fate and transport of free and dissolved gas. The novel visual technique developed in this study provided both quantitative and qualitative observations of gas-water mass transfer. Findings included interaction between free gas architecture and dissolved plume migration, plume geometry and longevity. The technique was applied to the injection of CO2 in source patterns expected for stray gas originating from oil and gas operations to measure dissolved phase concentrations of CO2 at high spatial and temporal resolutions. The data set is the first of its kind to provide high resolution quantification of gas-water dissolution, and will facilitate an improved understanding of the fundamental processes of gas movement and fate in these complex systems.

Environmental isotope investigation of groundwater flow in the Honey Lake Basin, California and Nevada

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

Rose, T.P.; Davisson, M.L.; Hudson, G.B.

The hydrology of Honey Lake Basin was studied using environmental isotope measurements of approximately 130 water samples collected during 1995 and 1996. The principal analytical methods included hydrogen, oxygen and carbon stable isotope ratio measurements, radiocarbon and tritium dating, and measurements of dissolved noble gas abundances.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations.

PubMed

Owens, Michael S; Cornwell, Jeffrey C

2016-08-03

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

Continuous high-frequency dissolved O2/Ar measurements by equilibrator inlet mass spectrometry.

PubMed

Cassar, Nicolas; Barnett, Bruce A; Bender, Michael L; Kaiser, Jan; Hamme, Roberta C; Tilbrook, Bronte

2009-03-01

The oxygen (O(2)) concentration in the surface ocean is influenced by biological and physical processes. With concurrent measurements of argon (Ar), which has similar solubility properties as oxygen, we can remove the physical contribution to O(2) supersaturation and determine the biological oxygen supersaturation. Biological O(2) supersaturation in the surface ocean reflects the net metabolic balance between photosynthesis and respiration, i.e., the net community productivity (NCP). We present a new method for continuous shipboard measurements of O(2)/Ar by equilibrator inlet mass spectrometry (EIMS). From these measurements and an appropriate gas exchange parametrization, NCP can be estimated at high spatial and temporal resolution. In the EIMS configuration, seawater from the ship's continuous intake flows through a cartridge enclosing a gas-permeable microporous membrane contactor. Gases in the headspace of the cartridge equilibrate with dissolved gases in the flowing seawater. A fused-silica capillary continuously samples headspace gases, and the O(2)/Ar ratio is measured by mass spectrometry. The ion current measurements on the mass spectrometer reflect the partial pressures of dissolved gases in the water flowing through the equilibrator. Calibration of the O(2)/Ar ion current ratio (32/40) is performed automatically every 2 h by sampling ambient air through a second capillary. A conceptual model demonstrates that the ratio of gases reaching the mass spectrometer is dependent on several parameters, such as the differences in molecular diffusivities and solubilities of the gases. Laboratory experiments and field observations performed by EIMS are discussed. We also present preliminary evidence that other gas measurements, such as N(2)/Ar and pCO(2) measurements, may potentially be performed with EIMS. Finally, we compare the characteristics of the EIMS with the previously described membrane inlet mass spectrometry (MIMS) approach.

A mass spectrometric line for tritium analysis of water and noble gas measurements from different water amounts in the range of microlitres and millilitres.

PubMed

Papp, Laszlo; Palcsu, Laszlo; Major, Zoltan; Rinyu, Laszlo; Tóth, Istvan

2012-01-01

This paper describes the procedure followed for noble gas measurements for litres, millilitres and microlitres of water samples in our laboratory, including sample preparation, mass spectrometric measurement procedure, and the complete calibrations. The preparation line extracts dissolved gases from water samples of volumes of 0.2 μ l to 3 l and it separates them as noble and other chemically active gases. Our compact system handles the following measurements: (i) determination of tritium concentration of environmental water samples by the (3)He ingrowth method; (ii) noble gas measurements from surface water and groundwater; and (iii) noble gas measurements from fluid inclusions of solid geological archives (e.g. speleothems). As a result, the tritium measurements have a detection limit of 0.012 TU, and the expectation value (between 1 and 20 TU) is within 0.2 % of the real concentrations with a standard deviation of 2.4 %. The reproducibility of noble gas measurements for water samples of 20-40 ml allows us to determine solubility temperatures by an uncertainty better than 0.5 °C. Moreover, noble gas measurements for tiny water amounts (in the microlitre range) show that the results of the performed calibration measurements for most noble gas isotopes occur with a deviation of less than 2 %. Theoretically, these precisions for noble gas concentrations obtained from measurements of waters samples of a few microlitres allow us to determine noble gas temperatures by an uncertainty of less than 1 °C. Here, we present the first noble gas measurements of tiny amounts of artificial water samples prepared under laboratory conditions.

On the role of sea-state in bubble-mediated air-sea gas flux during a winter storm

NASA Astrophysics Data System (ADS)

Liang, Jun-Hong; Emerson, Steven R.; D'Asaro, Eric A.; McNeil, Craig L.; Harcourt, Ramsey R.; Sullivan, Peter P.; Yang, Bo; Cronin, Meghan F.

2017-04-01

Oceanic bubbles play an important role in the air-sea exchange of weakly soluble gases at moderate to high wind speeds. A Lagrangian bubble model embedded in a large eddy simulation model is developed to study bubbles and their influence on dissolved gases in the upper ocean. The transient evolution of mixed-layer dissolved oxygen and nitrogen gases at Ocean Station Papa (50°N, 145°W) during a winter storm is reproduced with the model. Among different physical processes, gas bubbles are the most important in elevating dissolved gas concentrations during the storm, while atmospheric pressure governs the variability of gas saturation anomaly (the relative departure of dissolved gas concentration from the saturation concentration). For the same wind speed, bubble-mediated gas fluxes are larger during rising wind with smaller wave age than during falling wind with larger wave age. Wave conditions are the primary cause for the bubble gas flux difference: when wind strengthens, waves are less-developed with respect to wind, resulting in more frequent large breaking waves. Bubble generation in large breaking waves is favorable for a large bubble-mediated gas flux. The wave-age dependence is not included in any existing bubble-mediated gas flux parameterizations.

A simple bubbling system for measuring radon (222Rn) gas concentrations in water samples based on the high solubility of radon in olive oil.

PubMed

Al-Azmi, D; Snopek, B; Sayed, A M; Domanski, T

2004-01-01

Based on the different levels of solubility of radon gas in organic solvents and water, a bubbling system has been developed to transfer radon gas, dissolving naturally in water samples, to an organic solvent, i.e. olive oil, which is known to be a good solvent of radon gas. The system features the application of a fixed volume of bubbling air by introducing a fixed volume of water into a flask mounted above the system, to displace an identical volume of air from an air cylinder. Thus a gravitational flow of water is provided without the need for pumping. Then, the flushing air (radon-enriched air) is directed through a vial containing olive oil, to achieve deposition of the radon gas by another bubbling process. Following this, the vial (containing olive oil) is measured by direct use of gamma ray spectrometry, without the need of any chemical or physical processing of the samples. Using a standard solution of 226Ra/222Rn, a lowest measurable concentration (LMC) of radon in water samples of 9.4 Bq L(-1) has been achieved (below the maximum contaminant level of 11 Bq L(-1)).

Chemical and stable isotopic composition of water and gas in the Fort Union Formation of the Powder River Basin, Wyoming and Montana: Evidence for water/rock interaction and the biogenic origin of coalbed natural gas

USGS Publications Warehouse

Rice, Cynthia A.; Flores, Romeo M.; Stricker, Gary D.; Ellis, Margaret S.

2008-01-01

Significant amounts (> 36 million m3/day) of coalbed methane (CBM) are currently being extracted from coal beds in the Paleocene Fort Union Formation of the Powder River Basin of Wyoming and Montana. Information on processes that generate methane in these coalbed reservoirs is important for developing methods that will stimulate additional production. The chemical and isotopic compositions of gas and ground water from CBM wells throughout the basin reflect generation processes as well as those that affect water/rock interaction. Our study included analyses of water samples collected from 228 CBM wells. Major cations and anions were measured for all samples, δDH2O and δ18OH2O were measured for 199 of the samples, and δDCH4 of gas co-produced with water was measured for 100 of the samples. Results show that (1) water from Fort Union Formation coal beds is exclusively Na–HCO3-type water with low dissolved SO4 content (median < 1 mg/L) and little or no dissolved oxygen (< 0.15 mg/L), whereas shallow groundwater (depth generally < 120 m) is a mixed Ca–Mg–Na–SO4–HCO3 type; (2) water/rock interactions, such as cation exchange on clay minerals and precipitation/dissolution of CaCO3 and SO4 minerals, account for the accumulation of dissolved Na and depletion of Ca and Mg; (3) bacterially-mediated oxidation–reduction reactions account for high HCO3 (270–3310 mg/L) and low SO4 (median < 0.15 mg/L) values; (4) fractionation between δDCH4 (− 283 to − 328 per mil) and δDH2O (− 121 to − 167 per mil) indicates that the production of methane is primarily by biogenic CO2 reduction; and (5) values of δDH2O and δ18OH2O (− 16 to − 22 per mil) have a wide range of values and plot near or above the global meteoric water line, indicating that the original meteoric water has been influenced by methanogenesis and by being mixed with surface and shallow groundwater.

Air-water Gas Exchange Rates on a Large Impounded River Measured Using Floating Domes (Poster)

EPA Science Inventory

Mass balance models of dissolved gases in rivers typically serve as the basis for whole-system estimates of greenhouse gas emission rates. An important component of these models is the exchange of dissolved gases between air and water. Controls on gas exchange rates (K) have be...

Geopressured-geothermal test of the EDNA Delcambre No. 1 well, Tigre Lagoon Field, Vermilion Parish, Louisiana: analysis of water an dissolved natural gas. Final report

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

Hankins, B.E.; Karkalits, O.C.

1978-09-01

The Edna Delcambre et al. No. 1 gas well, shut-in since June 1975, was made available for the project. Two geopressured sand-bed aquifers were tested: sand No. 3 at a depth of 12,900 feet and sand No. 1 at a depth of 12,600 feet. Each aquifer was subjected to flow tests which lasted approximately three weeks in each case. Water samples were obtained during flow testing of the two geopressured aquifers. The water contained 11.3 to 13.3% dissolved solids. Several radioactive species were measured. Radium-226 was found to be approximately 10 times more concentrated than the average amount observed inmore » surface waters. No appreciable amount of heavy metals was detected. Recombination studies at bottom-hole conditions indicate the solubility of natural gas per barrel of water to be about 24 SCF. The methane content was 93 to 95%, and the gas had a heating value in the range of 1020 to 1070 Btu/cu.ft. During the flow tests, the gas/water ratio at the well-head was observed to be 45 to 88 SCF/Bbl water produced. (MHR)« less

The comparison of greenhouse gas emissions in sewage treatment plants with different treatment processes.

PubMed

Masuda, Shuhei; Sano, Itsumi; Hojo, Toshimasa; Li, Yu-You; Nishimura, Osamu

2018-02-01

Greenhouse gas emissions from different sewage treatment plants: oxidation ditch process, double-circulated anoxic-oxic process and anoxic-oxic process were evaluated based on the survey. The methane and nitrous oxide characteristics were discussed based on the gaseous and dissolved gas profiles. As a result, it was found that methane was produced in the sewer pipes and the primary sedimentation tank. Additionally, a ventilation system would promote the gasification of dissolved methane in the first treatment units. Nitrous oxide was produced and emitted in oxic tanks with nitrite accumulation inside the sewage treatment plant. A certain amount of nitrous oxide was also discharged as dissolved gas through the effluent water. If the amount of dissolved nitrous oxide discharge is not included, 7-14% of total nitrous oxide emission would be overlooked. Based on the greenhouse gas calculation, electrical consumption and the N 2 O emission from incineration process were major sources in all the plants. For greenhouse gas reduction, oxidation ditch process has an advantage over the other advanced systems due to lower energy consumption, sludge production, and nitrogen removal without gas stripping. Copyright © 2017 Elsevier Ltd. All rights reserved.

Total Dissolved Gas Monitoring in Chum Salmon Spawning Gravels Below Bonneville Dam

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

Arntzen, Evan V.; Geist, David R.; Panther, Jennifer L.

2007-01-30

At the request of the U.S. Army Corps of Engineers (Portland District), Pacific Northwest National Laboratory (PNNL) conducted research to determine whether total dissolved gas concentrations are elevated in chum salmon redds during spring spill operations at Bonneville Dam. The study involved monitoring the total dissolved gas levels at egg pocket depth and in the river at two chum salmon spawning locations downstream from Bonneville Dam. Dissolved atmospheric gas supersaturation generated by spill from Bonneville Dam may diminish survival of chum (Oncorhynchus keta) salmon when sac fry are still present in the gravel downstream from Bonneville Dam. However, no previousmore » work has been conducted to determine whether total dissolved gas (TDG) levels are elevated during spring spill operations within incubation habitats. The guidance used by hydropower system managers to provide protection for pre-emergent chum salmon fry has been to limit TDG to 105% after allowing for depth compensation. A previous literature review completed in early 2006 shows that TDG levels as low as 103% have been documented to cause mortality in sac fry. Our study measured TDG in the incubation environment to evaluate whether these levels were exceeded during spring spill operations. Total dissolved gas levels were measured within chum salmon spawning areas near Ives Island and Multnomah Falls on the Columbia River. Water quality sensors screened at egg pocket depth and to the river were installed at both sites. At each location, we also measured dissolved oxygen, temperature, specific conductance, and water depth to assist with the interpretation of TDG results. Total dissolved gas was depth-compensated to determine when levels were high enough to potentially affect sac fry. This report provides detailed descriptions of the two study sites downstream of Bonneville Dam, as well as the equipment and procedures employed to monitor the TDG levels at the study sites. Results of the monitoring at both sites are then presented in both text and graphics. The findings and recommendations for further research are discussed, followed by a listing of the references cited in the report.« less

A membrane inlet mass spectrometry system for noble gases at natural abundances in gas and water samples.

PubMed

Visser, Ate; Singleton, Michael J; Hillegonds, Darren J; Velsko, Carol A; Moran, Jean E; Esser, Bradley K

2013-11-15

Noble gases dissolved in groundwater can reveal paleotemperatures, recharge conditions, and precise travel times. The collection and analysis of noble gas samples are cumbersome, involving noble gas purification, cryogenic separation and static mass spectrometry. A quicker and more efficient sample analysis method is required for introduced tracer studies and laboratory experiments. A Noble Gas Membrane Inlet Mass Spectrometry (NG-MIMS) system was developed to measure noble gases at natural abundances in gas and water samples. The NG-MIMS system consists of a membrane inlet, a dry-ice water trap, a carbon-dioxide trap, two getters, a gate valve, a turbomolecular pump and a quadrupole mass spectrometer equipped with an electron multiplier. Noble gases isotopes (4)He, (22)Ne, (38)Ar, (84)Kr and (132)Xe are measured every 10 s. The NG-MIMS system can reproduce measurements made on a traditional noble gas mass spectrometer system with precisions of 2%, 8%, 1%, 1% and 3% for He, Ne, Ar, Kr and Xe, respectively. Noble gas concentrations measured in an artificial recharge pond were used to monitor an introduced xenon tracer and to reconstruct temperature variations to within 2 °C. Additional experiments demonstrated the capability to measure noble gases in gas and in water samples, in real time. The NG-MIMS system is capable of providing analyses sufficiently accurate and precise for introduced noble gas tracers at managed aquifer recharge facilities, groundwater fingerprinting based on excess air and noble gas recharge temperature, and field and laboratory studies investigating ebullition and diffusive exchange. Copyright © 2013 John Wiley & Sons, Ltd.

Effect of dissolved gases in water on acoustic cavitation and bubble growth rate in 0.83 MHz megasonic of interest to wafer cleaning.

PubMed

Kang, Bong-Kyun; Kim, Min-Su; Park, Jin-Goo

2014-07-01

Changes in the cavitation intensity of gases dissolved in water, including H2, N2, and Ar, have been established in studies of acoustic bubble growth rates under ultrasonic fields. Variations in the acoustic properties of dissolved gases in water affect the cavitation intensity at a high frequency (0.83 MHz) due to changes in the rectified diffusion and bubble coalescence rate. It has been proposed that acoustic bubble growth rates rapidly increase when water contains a gas, such as hydrogen faster single bubble growth due to rectified diffusion, and a higher rate of coalescence under Bjerknes forces. The change of acoustic bubble growth rate in rectified diffusion has an effect on the damping constant and diffusivity of gas at the acoustic bubble and liquid interface. It has been suggested that the coalescence reaction of bubbles under Bjerknes forces is a reaction determined by the compressibility and density of dissolved gas in water associated with sound velocity and density in acoustic bubbles. High acoustic bubble growth rates also contribute to enhanced cavitation effects in terms of dissolved gas in water. On the other hand, when Ar gas dissolves into water under ultrasound field, cavitation behavior was reduced remarkably due to its lower acoustic bubble growth rate. It is shown that change of cavitation intensity in various dissolved gases were verified through cleaning experiments in the single type of cleaning tool such as particle removal and pattern damage based on numerically calculated acoustic bubble growth rates. Copyright © 2014 Elsevier B.V. All rights reserved.

Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

PubMed Central

Miettinen, Hanna; Kietäväinen, Riikka; Sohlberg, Elina; Numminen, Mikko; Ahonen, Lasse; Itävaara, Merja

2015-01-01

Pyhäsalmi mine in central Finland provides an excellent opportunity to study microbial and geochemical processes in a deep subsurface crystalline rock environment through near-vertical drill holes that reach to a depth of more than two kilometers below the surface. However, microbial sampling was challenging in this high-pressure environment. Nucleic acid yields obtained were extremely low when compared to the cell counts detected (1.4 × 104 cells mL−1) in water. The water for nucleic acid analysis went through high decompression (60–130 bar) during sampling, whereas water samples for detection of cell counts by microscopy could be collected with slow decompression. No clear cells could be identified in water that went through high decompression. The high-pressure decompression may have damaged part of the cells and the nucleic acids escaped through the filter. The microbial diversity was analyzed from two drill holes by pyrosequencing amplicons of the bacterial and archaeal 16S rRNA genes and from the fungal ITS regions from both DNA and RNA fractions. The identified prokaryotic diversity was low, dominated by Firmicute, Beta- and Gammaproteobacteria species that are common in deep subsurface environments. The archaeal diversity consisted mainly of Methanobacteriales. Ascomycota dominated the fungal diversity and fungi were discovered to be active and to produce ribosomes in the deep oligotrophic biosphere. The deep fluids from the Pyhäsalmi mine shared several features with other deep Precambrian continental subsurface environments including saline, Ca-dominated water and stable isotope compositions positioning left from the meteoric water line. The dissolved gas phase was dominated by nitrogen but the gas composition clearly differed from that of atmospheric air. Despite carbon-poor conditions indicated by the lack of carbon-rich fracture fillings and only minor amounts of dissolved carbon detected in formation waters, some methane was found in the drill holes. No dramatic differences in gas compositions were observed between different gas sampling methods tested. For simple characterization of gas composition the most convenient way to collect samples is from free flowing fluid. However, compared to a pressurized method a relative decrease in the least soluble gases may appear. PMID:26579109

Passive Sampling Provides Evidence for Neward Bay as a Source of Polychlorinated Dibenzo-p-Dioxins and Furans to the New York/New Jersey, USA, Atmosphere

EPA Science Inventory

Freely dissolved and gas phase polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the water column and atmosphere at five locations within Newark Bay (New Jersey, USA) from May 2008 to August 2009 with polyethylene (PE) passive ...

Gas hydrate formation rates from dissolved-phase methane in porous laboratory specimens

USGS Publications Warehouse

Waite, William F.; Spangenberg, E.K.

2013-01-01

Marine sands highly saturated with gas hydrates are potential energy resources, likely forming from methane dissolved in pore water. Laboratory fabrication of gas hydrate-bearing sands formed from dissolved-phase methane usually requires 1–2 months to attain the high hydrate saturations characteristic of naturally occurring energy resource targets. A series of gas hydrate formation tests, in which methane-supersaturated water circulates through 100, 240, and 200,000 cm3 vessels containing glass beads or unconsolidated sand, show that the rate-limiting step is dissolving gaseous-phase methane into the circulating water to form methane-supersaturated fluid. This implies that laboratory and natural hydrate formation rates are primarily limited by methane availability. Developing effective techniques for dissolving gaseous methane into water will increase formation rates above our observed (1 ± 0.5) × 10−7 mol of methane consumed for hydrate formation per minute per cubic centimeter of pore space, which corresponds to a hydrate saturation increase of 2 ± 1% per day, regardless of specimen size.

Regional Mapping of Gas Uptake by Blood and Tissue in the Human Lung using Hyperpolarized Xenon-129 MRI

PubMed Central

Qing, Kun; Ruppert, Kai; Jiang, Yun; Mata, Jaime F.; Miller, G. Wilson; Shim, Y. Michael; Wang, Chengbo; Ruset, Iulian C.; Hersman, F. William; Altes, Talissa A.; Mugler, John P.

2013-01-01

Purpose To develop a breath-hold acquisition for regional mapping of ventilation and the fractions of hyperpolarized xenon-129 (Xe129) dissolved in tissue (lung parenchyma and plasma) and red blood cells (RBCs), and to perform an exploratory study to characterize data obtained in human subjects. Materials and Methods A three-dimensional, multi-echo, radial-trajectory pulse sequence was developed to obtain ventilation (gaseous Xe129), tissue and RBC images in healthy subjects, smokers and asthmatics. Signal ratios (total dissolved Xe129 to gas, tissue-to-gas, RBC-to-gas and RBC-to-tissue) were calculated from the images for quantitative comparison. Results Healthy subjects demonstrated generally uniform values within coronal slices, and a gradient in values along the anterior-to-posterior direction. In contrast, images and associated ratio maps in smokers and asthmatics were generally heterogeneous and exhibited values mostly lower than those in healthy subjects. Whole-lung values of total dissolved Xe129 to gas, tissue-to-gas, and RBC-to-gas ratios in healthy subjects were significantly larger than those in diseased subjects. Conclusion Regional maps of tissue and RBC fractions of dissolved Xe129 were obtained from a short breath-hold acquisition, well tolerated by healthy volunteers and subjects with obstructive lung disease. Marked differences were observed in spatial distributions and overall amounts of Xe129 dissolved in tissue and RBCs among healthy subjects, smokers and asthmatics. PMID:23681559

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

Duke, Daniel J.; Kastengren, Alan L.; Swantek, Andrew B.

The dynamics of dissolved gas and cavitation are strongly coupled, yet these phenomena are difficult to measure in-situ. Both create voids in the fluid that can be difficult to distinguish. In this paper, we present an application of X-ray fluorescence in which liquid density and total noncondensible gas concentration (both dissolved and nucleated) are simultaneously measured. The liquid phase is doped with 400 ppm of a bromine tracer, and dissolved air is removed and substituted with krypton. Fluorescent emission at X-ray wavelengths is simultaneously excited from the Br and Kr with a focused monochromatic X-ray beam from a synchrotron source.more » We measure the flow in a cavitating nozzle 0.5 mm in diameter. From Br fluorescence, total displacement of the liquid is measured. From Kr fluorescence, the mass fraction of both dissolved and nucleated gas is measured. Volumetric displacement of liquid due to both cavitation and gas precipitation can be separated through estimation of the local equilibrium dissolved mass fraction. The uncertainty in the line of sight projected densities of the liquid and gas phases is 4–6 %. The high fluorescence yields and energies of Br and Kr allow small mass fractions of gas to be measured, down to 10 -5, with an uncertainty of 8 %. Finally, these quantitative measurements complement existing optical diagnostic techniques and provide new insight into the diffusion of gas into cavitation bubbles, which can increase their internal density, pressure and lifetimes by orders of magnitude.« less

Hydrothermal Synthesis of Various Hierarchical ZnO Nanostructures and Their Methane Sensing Properties

PubMed Central

Zhou, Qu; Chen, Weigen; Xu, Lingna; Peng, Shudi

2013-01-01

Hierarchical flower-like ZnO nanorods, net-like ZnO nanofibers and ZnO nanobulks have been successfully synthesized via a surfactant assisted hydrothemal method. The synthesized products were characterized by X-ray powder diffraction and field emission scanning electron microscopy, respectively. A possible growth mechanism of the various hierarchical ZnO nanostructures is discussed in detail. Gas sensors based on the as-prepared ZnO nanostructures were fabricated by screen-printing on a flat ceramic substrate. Furthermore, their gas sensing characteristics towards methane were systematically investigated. Methane is an important characteristic hydrocarbon contaminant found dissolved in power transformer oil as a result of faults. We find that the hierarchical flower-like ZnO nanorods and net-like ZnO nanofibers samples show higher gas response and lower operating temperature with rapid response-recovery time compared to those of sensors based on ZnO nanobulks. These results present a feasible way of exploring high performance sensing materials for on-site detection of characteristic fault gases dissolved in transformer oil. PMID:23666136

In situ spectrophotometric measurement of dissolved inorganic carbon in seawater.

PubMed

Liu, Xuewu; Byrne, Robert H; Adornato, Lori; Yates, Kimberly K; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

2013-10-01

Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

Preliminary results from exploratory sampling of wells for the California oil, gas, and groundwater program, 2014–15

USGS Publications Warehouse

McMahon, Peter B.; Kulongoski, Justin T.; Wright, Michael T.; Land, Michael T.; Landon, Matthew K.; Cozzarelli, Isabelle M.; Vengosh, Avner; Aiken, George R.

2016-08-03

This report evaluates the utility of the chemical, isotopic, and groundwater-age tracers for assessing sources of salinity, methane, and petroleum hydrocarbons in groundwater overlying or near several California oil fields. Tracers of dissolved organic carbon inoil-field-formation water are also discussed. Tracer data for samples collected from 51 water wells and 4 oil wells are examined.

Investigation of the noble gas solubility in H 2O-CO 2 bearing silicate liquids at moderate pressure II: the extended ionic porosity (EIP) model

NASA Astrophysics Data System (ADS)

Nuccio, P. M.; Paonita, A.

2000-12-01

A semi-theoretical model is proposed to predict partitioning of noble gases between any silicate liquid and a H 2O-CO 2 gas phase with noble gas as a minor component, in a large range of pressures (at least up to 300 MPa). The model is based on the relationship between the concentration of dissolved noble gas and ionic porosity of the melt, found by Carroll and Stolper [Geochim. Cosmochim. Acta 57 (1993) 5039-5051] for H 2O-CO 2 free melts. It evaluates the effect of dissolved H 2O and CO 2 on the melt ionic porosity and, consequently on Henry's constants of noble gases. The fugacities of the noble gases in the H 2O-CO 2-noble gas mixtures are also considered in our equilibrium calculations of dissolved gas by using a modified Redlich-Kwong equation of state for the H 2O-CO 2-noble gas system. The formulated model (referred to as the extended ionic porosity model) clearly predicts a positive dependence of noble gas solubility on dissolved H 2O in melt, which becomes negligible when water concentration is higher than 3 wt%. Oppositely, noble gas solubility decreases as a consequence of increasing CO 2 in both basaltic and rhyolitic melts. The increase of noble gas solubility as a consequence of H 2O addition to the melt grows exponentially with the increase of the noble gas atomic size. As a result, although xenon solubility is much lower than the helium solubility in anhydrous melts, they become almost comparable at several percent of dissolved H 2O in the melt. On this basis, an exponential augmentation of the number of large free spaces in silicate liquid can be inferred in relation to increasing dissolved H 2O. Comparison between our predicted values and available experimental data [A. Paonita et al., Earth Planet. Sci. Lett. 181 (2000) 595-604] shows good agreement. At present, the EIP model is the unique tool which predicts how the main volatiles in magmatic systems affect the noble gas solubility in silicate melts, therefore it should be taken into account for future studies of noble gas fractionation in degassing natural magmas.

Chemical fractionation-enhanced structural characterization of marine dissolved organic matter

NASA Astrophysics Data System (ADS)

Arakawa, N.; Aluwihare, L.

2016-02-01

Describing the molecular fingerprint of dissolved organic matter (DOM) requires sample processing methods and separation techniques that can adequately minimize its complexity. We have employed acid hydrolysis as a way to make the subcomponents of marine solid phase-extracted (PPL) DOM more accessible to analytical techniques. Using a combination of NMR and chemical derivatization or reduction analyzed by comprehensive (GCxGC) gas chromatography, we observed chemical features strikingly similar to terrestrial DOM. In particular, we observed reduced alicylic hydrocarbons believed to be the backbone of previously identified carboxylic rich alicyclic material (CRAM). Additionally, we found carbohydrates, amino acids and small lipids and acids.

Dissolution of Hydrocarbon Gas Hydrates in Seawater at 1030-m; Effects of Porosity, Structure, and Compositional Variation as Determined by High-Definition Video and SEM Imaging.

NASA Astrophysics Data System (ADS)

Stern, L. A.; Peltzer, E. T.; Durham, W. B.; Kirby, S. H.; Brewer, P. G.; Circone, S.; Rehder, G.

2002-12-01

We compare dissolution rates of pure, porous, compacted, and oil-contaminated sI methane hydrate and sII methane-ethane hydrate to rates measured previously on pure, compacted, sI methane hydrate and sI carbon dioxide hydrate (Rehder et al., Fall AGU 2001). Laboratory-synthesized test specimens were used in both studies, allowing characterization of test materials prior to their transport and exposure to seawater at 1030-meter depth on the Monterey Canyon seafloor, off coastal Moss Landing, CA. Although pressure and temperature (P-T) conditions at this site are within the nominal P-T equilibrium fields of all gas hydrates tested here, the seawater is undersaturated with respect to the hydrate-forming gas species. Hence, samples dissolve with time, at a rate dependent on water current flow. Four samples were deployed in this second experiment: (1) pure, 30% porous methane hydrate; (2) pure, compacted methane hydrate; (3) pure methane hydrate compacted and then contaminated with a low-T mineral oil; and (4) pure, compacted sII methane-ethane hydrate with methane:ethane molar ratio 0.72. Samples were transferred by pressure vessel at 0 ° C and 15 MPa to the seafloor observatory via the MBARI remotely operated vehicle Ventana. Samples were then exposed to the deep ocean environment and monitored by HDTV camera for several hours at the beginning and end of a 25-hour period. Local current speed and direction were also measured throughout the experiment. Those samples that did not undergo complete dissolution after 25 h were successfully recovered to the laboratory for subsequent analysis by scanning electron microscopy (SEM). Previously, video analysis showed dissolution rates corresponding to 4.0 +/- 0.5 mmole CO2/m2 s for compacted CO2 hydrate samples, and 0.37 +/- 0.03 mmole CH4/m2s for compacted methane hydrate samples (Rehder et al, AGU 2001). The ratio of dissolution rates fits a simple diffusive boundary layer model that incorporates relative gas solubilities appropriate to the field site. These calculations assume that dissolution occurred only along the outer (i.e. imaged) surface of the samples. This assumption is now validated by SEM analysis of recovered samples from the second dive, showing little to no internal alteration of compacted material following their partial dissolution. Quantitative comparison of results from the two dives poses challenges due to variations in sample size and orientation. However, both compacted methane hydrate samples from the second dive in fact exhibited comparable behavior to that measured in the previous experiment; the oily sample did not dissolve at a slower rate, as might be expected if a hydrophobic contaminant inhibits seawater contact. Surprisingly, the porous methane hydrate exhibited significantly slower face retreat than its compacted counterparts. The sII methane-ethane hydrate dissolved measurably slower than all other samples, consistent with the solubility properties of its guest components. While these results represent only a first step in emulating the more complex interactions of seawater with naturally occurring hydrate-bearing sediments, such end member studies should aid preliminary modelling investigations of the chemical stability and lifetime of gas hydrates exposed at the seafloor.

Simultaneous determination of dissolved gases and moisture in mineral insulating oils by static headspace gas chromatography with helium photoionization pulsed discharge detection.

PubMed

Jalbert, J; Gilbert, R; Tétreault, P

2001-07-15

This paper presents the development of a static headspace capillary gas chromatographic method (HS-GC) for simultaneously determining dissolved gases (H2, O2, N2, CO, CO2, CH4, C2H6, C2H4, C2H2, C3H8) and moisture from a unique 15-mL mineral oil sample. A headspace sampler device is used to equilibrate the sample species in a two-phase system under controlled temperature and agitation conditions. A portion of the equilibrated species is then automatically split-injected into two chromatographic channels mounted on the same GC for their separation. The hydrocarbons and the lighter gases are separated on the first channel by a GS-Q column coupled with a MolSieve 5-A column via a bypass valve, while the moisture is separated on the second channel using a Stabilwax column. The analytes are detected by using two universal pulsed-discharge helium ionization detectors (PDHID). The performance of the method was established using equilibrated vials containing known amounts of gas mixture, water, and blank oil. The signal is linear over the concentration ranges normally found for samples collected from open-breathing power transformers. Determination sensitivity varies with the nature of the species considered with values as high as 21 500 A x 10(-9) s (microg/ g)(-1) for H2O, 46-216 A x 10(-9) s (microL/L)(-1) for the hydrocarbons and carbon oxides, and as low as 8-21 A x 10(-9) s (microL/L)(-1) for the O2 and N2 permanent gases. The detection limit of the method is between 0.08 and 6 microL/L for the dissolved gases, except for O2, N2, and CO2, where higher values are observed due to air intrusion during sampler operations, and 0.1 microg/g for the dissolved water. Ten consecutive measurements in the low and high levels of the calibration curves have shown a precision better than 12% and 6%, respectively, in all cases. A comparison study between the HS-GC method and the ASTM standard procedures on 31 field samples showed a very good agreement of the results. The advantages of configuring the arrangement with two PDHID over the conventional flame ionization and thermal conductivity detectors were clearly demonstrated.

Evaluation of headspace equilibration methods for quantifying greenhouse gases in groundwater.

PubMed

Jahangir, M M R; Johnston, P; Khalil, M I; Grant, J; Somers, C; Richards, K G

2012-11-30

The objective of the study was to evaluate the different headspace equilibration methods for the quantification of dissolved greenhouse gases in groundwater. Groundwater samples were collected from wells with contrasting hydrogeochemical properties and degassed using the headspace equilibration method. One hundred samples from each well were randomly selected, treatments were applied and headspace gases analysed by gas chromatography. Headspace equilibration treatments varied helium (He):water ratio, shaking time and standing time. Mean groundwater N(2)O, CO(2) and CH(4) concentrations were 0.024 mg N L(-1), 13.71 mg C L(-1) and 1.63 μg C L(-1), respectively. All treatments were found to significantly influence dissolved gas concentrations. Considerable differences in the optimal He:water ratio and standing time were observed between the three gases. For N(2)O, CO(2) and CH(4) the optimum operating points for He:water ratio was 4.4:1, 3:1 and 3.4:1; shaking time was 13, 12 and 13 min; and standing time was 63, 17 and 108 min, respectively. The headspace equilibration method needs to be harmonised to ensure comparability between studies. The experiment reveals that He:water ratio 3:1 and shaking time 13 min give better estimation of dissolved gases than any lower or higher ratios and shaking times. The standing time 63, 17 and 108 min should be applied for N(2)O, CO(2) and CH(4), respectively. Copyright © 2012. Published by Elsevier Ltd.

A stream-based methane monitoring approach for evaluating groundwater impacts associated with unconventional gas development.

PubMed

Heilweil, Victor M; Stolp, Bert J; Kimball, Briant A; Susong, David D; Marston, Thomas M; Gardner, Philip M

2013-01-01

Gaining streams can provide an integrated signal of relatively large groundwater capture areas. In contrast to the point-specific nature of monitoring wells, gaining streams coalesce multiple flow paths. Impacts on groundwater quality from unconventional gas development may be evaluated at the watershed scale by the sampling of dissolved methane (CH4 ) along such streams. This paper describes a method for using stream CH4 concentrations, along with measurements of groundwater inflow and gas transfer velocity interpreted by 1-D stream transport modeling, to determine groundwater methane fluxes. While dissolved ionic tracers remain in the stream for long distances, the persistence of methane is not well documented. To test this method and evaluate CH4 persistence in a stream, a combined bromide (Br) and CH4 tracer injection was conducted on Nine-Mile Creek, a gaining stream in a gas development area in central Utah. A 35% gain in streamflow was determined from dilution of the Br tracer. The injected CH4 resulted in a fivefold increase in stream CH4 immediately below the injection site. CH4 and δ(13) CCH4 sampling showed it was not immediately lost to the atmosphere, but remained in the stream for more than 2000 m. A 1-D stream transport model simulating the decline in CH4 yielded an apparent gas transfer velocity of 4.5 m/d, describing the rate of loss to the atmosphere (possibly including some microbial consumption). The transport model was then calibrated to background stream CH4 in Nine-Mile Creek (prior to CH4 injection) in order to evaluate groundwater CH4 contributions. The total estimated CH4 load discharging to the stream along the study reach was 190 g/d, although using geochemical fingerprinting to determine its source was beyond the scope of the current study. This demonstrates the utility of stream-gas sampling as a reconnaissance tool for evaluating both natural and anthropogenic CH4 leakage from gas reservoirs into groundwater and surface water. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

The distribution of methane in groundwater in Alberta (Canada) and associated aqueous geochemistry conditions

NASA Astrophysics Data System (ADS)

Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Millot, Romain; Kloppmann, Wolfram

2016-04-01

Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish: (a) natural in-situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. We have conducted a NSERC-ANR co-funded baseline study investigating the occurrence of methane in shallow groundwater of Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. Our objective was to assess the occurrence and sources of methane in shallow groundwaters and to also characterize the hydrochemical environment in which the methane was formed or transformed through redox processes. Ultimately our aim was to determine whether methane was formed in-situ or whether it migrated from deeper formations into shallow aquifers. Combining hydrochemical and dissolved and free geochemical gas data from 372 groundwater samples obtained from 186 monitoring wells of the provincial groundwater observation well network (GOWN) in Alberta, it was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of dissolved biogenic methane (> 0.01 mM or > 0.2 mg/L), characterized by δ13CCH4 values < -55‰, occurred in anoxic Na-Cl, Na-HCO3 and Na-HCO3-Cl type groundwater with negligible concentrations of nitrate and sulfate suggesting that methane was formed in-situ under methanogenic conditions consistent with the redox ladder concept. Despite quite variable gas concentrations and a wide range of δ13CCH4 values in baseline groundwater samples, no conclusive evidence was found for deep thermogenic gas that had migrated in significant amounts into shallow aquifers either naturally or via anthropogenically induced pathways. This study shows that the combined interpretation of aqueous geochemistry data in concert with the chemical and isotopic composition of dissolved and/or free gas can yield unprecedented insights into formation or migration of methane in shallow groundwater. This enables the assessment of cross-formational methane migration and provides an understanding of alkane gas sources and pathways necessary for a stringent baseline definition in the context of current and future unconventional hydrocarbon exploration and exploitation.

Fire, Carbon, and Greenhouse Gas Emissions from Aquatic Ecosystems in the Yukon-Kuskokwim River Delta

NASA Astrophysics Data System (ADS)

Schade, J. D.; Kuhn, M. A.; Mann, P. J.; Holmes, R. M.; Natali, S.; Ludwig, S.; Wagner, S.

2016-12-01

Northern latitudes are experiencing rapid changes in climate that are profoundly altering permafrost-dominated ecosystems. Increased permafrost thaw and fire frequency and severity are changing the structure and function of these ecosystems in ways likely to alter greenhouse gas (GHG) emission, leading to feedbacks on climate that may accelerate warming. Our objective was to investigate changes in GHG emissions and carbon and nitrogen dynamics in aquatic ecosystems in response to recent fires in the Yukon-Kuskokwim river delta in western Alaska. In summer 2015, more area in the YK Delta burned then in the previous 74 years combined (726 km2 in 2015 vs. 477 km2 during 1940-2014). In June of 2016, we sampled water and dissolved gases from a variety of aquatic ecosystems, including small upland ponds and wetlands and streams lower in the landscape, in recently burned and control sites near the Kuka Creek 2015 burn scar in the Yukon Delta National Wildlife Refuge. We measured a range of physical parameters, including water temperature, conductivity, dissolved oxygen, and pH. We also estimated fluxes of CO2 and CH4 from surface waters using a floating chamber connected to a Los Gatos Ultraportable gas analyzer. Water samples were analyzed for dissolved organic carbon (DOC) and total dissolved nitrogen (TDN). Results show reduced DOC concentrations in small upland ponds in burned sites and evidence for loss of DOC downslope in control sites. In contrast, TDN concentration was higher in streams draining burned sites, suggesting fire mobilized N in soils, which was then transported to downslope ecosystems. Furthermore, fire generally increased pH, particularly in small ponds. Finally, we observed 3-4 fold higher CO2 and CH4 fluxes from aquatic ecosystems in burned sites as compared with control sites. We hypothesize that this is due to increased thaw depth and increased pH, which combine to increase resource availability and release methane-producing microbes from the constraints of low pH. These results suggest a strong positive feedback on climate from short-term responses of aquatic ecosystems to fire in the Arctic.

Determination of the δ34S of low-concentration sulfate in water; RSIL lab code 1949

USGS Publications Warehouse

Revesz, Kinga; Qi, Haiping; Coplen, Tyler B.

2006-01-01

The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1949 is to determine the δ(34S/32S), abbreviated as δ34S, of dissolved sulfate having a concentration less than 20 milligrams per liter. Dissolved sulfate is collected on an anion-exchange resin in the field, eluted in the laboratory with 3 M KCl, and precipitated with BaCl2 at pH 3 to 4 as BaSO4. The precipitated BaSO4 is filtered and dried before introduction into an elemental analyzer (EA) Carlo Erba NC 2500. The EA is used to convert sulfur in a BaSO4 solid sample into SO2 gas, and the EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines differences in the isotope-amount ratios of stable sulfur isotopes (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in a tin capsule and loaded into the Costech Zero Blank Autosampler of the EA. Under computer control, samples are dropped into a heated reaction tube that combines the oxidation and reduction reactions. The combustion takes place in a helium atmosphere containing an excess of oxygen gas at the oxidation zone at the top of the reaction tube. Combustion products are transported by a helium carrier through the reduction zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph. The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through a Finnigan MAT (now Thermo Scientific) ConFlo II interface, which is also used to inject SO2 reference gas and helium for sample dilution. The IRMS is a Thermo Scientific Delta V Plus CF-IRMS. It has a universal triple collector with two wide cups and a narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion beams from SO2 are as follows: m/z 64 = SO2 = 32S16O16O; m/z 66 = SO2 = 34S16O16O primarily.

The suitability of using dissolved gases to determine groundwater discharge to high gradient streams

USGS Publications Warehouse

Gleeson, Tom; Manning, Andrew H.; Popp, Andrea; Zane, Mathew; Clark, Jordan F.

2018-01-01

Determining groundwater discharge to streams using dissolved gases is known to be useful over a wide range of streamflow rates but the suitability of dissolved gas methods to determine discharge rates in high gradient mountain streams has not been sufficiently tested, even though headwater streams are critical as ecological habitats and water resources. The aim of this study is to test the suitability of using dissolved gases to determine groundwater discharge rates to high gradient streams by field experiments in a well-characterized, high gradient mountain stream and a literature review. At a reach scale (550 m) we combined stream and groundwater radon activity measurements with an in-stream SF6 tracer test. By means of numerical modeling we determined gas exchange velocities and derived very low groundwater discharge rates (∼15% of streamflow). These groundwater discharge rates are below the uncertainty range of physical streamflow measurements and consistent with temperature, specific conductance and streamflow measured at multiple locations along the reach. At a watershed-scale (4 km), we measured CFC-12 and δ18O concentrations and determined gas exchange velocities and groundwater discharge rates with the same numerical model. The groundwater discharge rates along the 4 km stream reach were highly variable, but were consistent with the values derived in the detailed study reach. Additionally, we synthesized literature values of gas exchange velocities for different stream gradients which show an empirical relationship that will be valuable in planning future dissolved gas studies on streams with various gradients. In sum, we show that multiple dissolved gas tracers can be used to determine groundwater discharge to high gradient mountain streams from reach to watershed scales.

The suitability of using dissolved gases to determine groundwater discharge to high gradient streams

NASA Astrophysics Data System (ADS)

Gleeson, Tom; Manning, Andrew H.; Popp, Andrea; Zane, Matthew; Clark, Jordan F.

2018-02-01

Determining groundwater discharge to streams using dissolved gases is known to be useful over a wide range of streamflow rates but the suitability of dissolved gas methods to determine discharge rates in high gradient mountain streams has not been sufficiently tested, even though headwater streams are critical as ecological habitats and water resources. The aim of this study is to test the suitability of using dissolved gases to determine groundwater discharge rates to high gradient streams by field experiments in a well-characterized, high gradient mountain stream and a literature review. At a reach scale (550 m) we combined stream and groundwater radon activity measurements with an in-stream SF6 tracer test. By means of numerical modeling we determined gas exchange velocities and derived very low groundwater discharge rates (∼15% of streamflow). These groundwater discharge rates are below the uncertainty range of physical streamflow measurements and consistent with temperature, specific conductance and streamflow measured at multiple locations along the reach. At a watershed-scale (4 km), we measured CFC-12 and δ18O concentrations and determined gas exchange velocities and groundwater discharge rates with the same numerical model. The groundwater discharge rates along the 4 km stream reach were highly variable, but were consistent with the values derived in the detailed study reach. Additionally, we synthesized literature values of gas exchange velocities for different stream gradients which show an empirical relationship that will be valuable in planning future dissolved gas studies on streams with various gradients. In sum, we show that multiple dissolved gas tracers can be used to determine groundwater discharge to high gradient mountain streams from reach to watershed scales.

Characterizing Dissolved Gases in Cryogenic Liquid Fuels

NASA Astrophysics Data System (ADS)

Richardson, Ian A.

Pressure-Density-Temperature-Composition (PrhoT-x) measurements of cryogenic fuel mixtures are a historical challenge due to the difficulties of maintaining cryogenic temperatures and precision isolation of a mixture sample. For decades NASA has used helium to pressurize liquid hydrogen propellant tanks to maintain tank pressure and reduce boil off. This process causes helium gas to dissolve into liquid hydrogen creating a cryogenic mixture with thermodynamic properties that vary from pure liquid hydrogen. This can lead to inefficiencies in fuel storage and instabilities in fluid flow. As NASA plans for longer missions to Mars and beyond, small inefficiencies such as dissolved helium in liquid propellant become significant. Traditional NASA models are unable to account for dissolved helium due to a lack of fundamental property measurements necessary for the development of a mixture Equation Of State (EOS). The first PrhoT-x measurements of helium-hydrogen mixtures using a retrofitted single-sinker densimeter, magnetic suspension microbalance, and calibrated gas chromatograph are presented in this research. These measurements were used to develop the first multi-phase EOS for helium-hydrogen mixtures which was implemented into NASA's Generalized Fluid System Simulation Program (GFSSP) to determine the significance of mixture non-idealities. It was revealed that having dissolved helium in the propellant does not have a significant effect on the tank pressurization rate but does affect the rate at which the propellant temperature rises. PrhoT-x measurements are conducted on methane-ethane mixtures with dissolved nitrogen gas to simulate the conditions of the hydrocarbon seas of Saturn's moon Titan. Titan is the only known celestial body in the solar system besides Earth with stable liquid seas accessible on the surface. The PrhoT-x measurements are used to develop solubility models to aid in the design of the Titan Submarine. NASA is currently designing the submarine to explore the depths of Titan's methane-ethane seas to study the evolution of hydrocarbons in the universe and provide a pathfinder for future submersible designs. In addition, effervescence and freezing liquid line measurements on various liquid methane-ethane compositions with dissolved gaseous nitrogen are presented from 1.5 bar to 4.5 bar and temperatures from 92 K to 96 K to improve simulations of the conditions of the seas. These measurements will be used to validate sea property and bubble incipience models for the Titan Submarine design.

Trace element distributions in the water column near the Deepwater Horizon well blowout.

PubMed

Joung, DongJoo; Shiller, Alan M

2013-03-05

To understand the impact of the Deepwater Horizon well blowout on dissolved trace element concentrations, samples were collected from areas around the oil rig explosion site during four cruises in early and late May 2010, October 2010, and October 2011. In surface waters, Ba, Fe, Cu, Ni, Mn, and Co were relatively well correlated with salinity during all cruises, suggesting mixing with river water was the main influence on metal distributions in these waters. However, in deep oil/gas plumes (1000-1400 m depth), modestly elevated concentrations of Co and Ba were observed in late May, compared with postblowout conditions. Analysis of the oil itself along with leaching experiments confirm the oil as the source of the Co, whereas increased Ba was likely due to drilling mud used in the top kill attempt. Deep plume dissolved Mn largely reflected natural benthic input, though some samples showed slight elevation probably associated with the top kill. Dissolved Fe concentrations were low and also appeared largely topographically controlled and reflective of benthic input. Estimates suggest that microbial Fe demand may have affected the Fe distribution but probably not to the extent of Fe becoming a growth-limiting factor. Experiments showed that the dispersant can have some limited impact on dissolved-particulate metal partitioning.

How plasma induced oxidation, oxygenation, and de-oxygenation influences viability of skin cells

NASA Astrophysics Data System (ADS)

Oh, Jun-Seok; Strudwick, Xanthe; Short, Robert D.; Ogawa, Kotaro; Hatta, Akimitsu; Furuta, Hiroshi; Gaur, Nishtha; Hong, Sung-Ha; Cowin, Allison J.; Fukuhara, Hideo; Inoue, Keiji; Ito, Masafumi; Charles, Christine; Boswell, Roderick W.; Bradley, James W.; Graves, David B.; Szili, Endre J.

2016-11-01

The effect of oxidation, oxygenation, and de-oxygenation arising from He gas jet and He plasma jet treatments on the viability of skin cells cultured in vitro has been investigated. He gas jet treatment de-oxygenated cell culture medium in a process referred to as "sparging." He plasma jet treatments oxidized, as well as oxygenated or de-oxygenated cell culture medium depending on the dissolved oxygen concentration at the time of treatment. He gas and plasma jets were shown to have beneficial or deleterious effects on skin cells depending on the concentration of dissolved oxygen and other oxidative molecules at the time of treatment. Different combinations of treatments with He gas and plasma jets can be used to modulate the concentrations of dissolved oxygen and other oxidative molecules to influence cell viability. This study highlights the importance of a priori knowledge of the concentration of dissolved oxygen at the time of plasma jet treatment, given the potential for significant impact on the biological or medical outcome. Monitoring and controlling the dynamic changes in dissolved oxygen is essential in order to develop effective strategies for the use of cold atmospheric plasma jets in biology and medicine.

Oceanographic Setting Dominates Methane Transport Through the Water Column in the Shallow Area West of Prins Karls Forland, Arctic Ocean

NASA Astrophysics Data System (ADS)

Silyakova, A.; Jansson, P.; Serov, P.; Graves, C. A.; Niemann, H.; Grundger, F.; Ferre, B.; Mienert, J.

2016-02-01

The area west of Prins Karls Forland (PKF, West Spitsbergen) in the Arctic Ocean, restricted to 90 m water depth, is known for a large amount of shallow active gas flares. Gas flares are streams of bubbles that contain mostly methane, which is a potent greenhouse gas. The important questions for many areas with discovered gas flares are: Does this gas reach the atmosphere? What controls the vertical and horizontal distribution of dissolved methane away from the source on the seafloor? Is all dissolved methane detected above gas flares released from those flares or does it partially originate from other areas (eg. Storfjorden, or area of deeper flares on the PKF slope)? The present study is based on two repeated oceanographic surveys conducted in the summers of 2014 and 2015. During the surveys, we sampled 64 CTD stations in a grid above a 30 x 15 km area with active methane flares. Vertical profiles of temperature (T) and salinity (S), as well as TS diagrams indicate very different oceanographic settings during the two surveys. Warm and saline Atlantic waters originating from the West Spitsbergen Current prevailed during the 2014 campaign. In 2015, in contrast, waters were distinctly less saline and cooler. These waters originate from the East-Spitsbergen current that flows northwards over the shelf from the Barents Sea around the southern tip of Spitsbergen. The water mass was furthermore influenced by local sources from the fjords. In both years, we observed strong vertical gradients in the distribution of dissolved methane in the water column above gas flares, with only 4% methane concentrations at the sea surface when compared to bottom waters. However, the circulation of the dominant water masses mainly controlled the horizontal distribution of methane in the water column in the specific year. We discuss oceanographic processes and mechanisms responsible for methane transport and transformation in the study area. This study is funded by CAGE (Centre for Arctic Gas Hydrate, Environment and Climate), Norwegian Research Council grant no. 223259.

Water quality in the vicinity of Mosquito Creek Lake, Trumbull County, Ohio, in relation to the chemistry of locally occurring oil, natural gas, and brine

USGS Publications Warehouse

Barton, G.J.; Burruss, R.C.; Ryder, R.T.

1998-01-01

Environmental samples collected in the Mosquito Creek Lake area were used to characterize water quality in relation to the chemistry of locally occurring oil, natural gas, and brine and to establish baseline water quality. Mosquito Creek Lake (a manmade reservoir) and the shallow bedrock aquifers near the lake are major sources of potable water in central Trumbull County. The city of Warren relies on the lake as a sole source of potable water. Some of the lake bottom may be in direct hydraulic connection with the underlying aquifers. The city of Cortland, along the southeastern shore of the lake, relies on the Cussewago Sandstone aquifer as a sole source of potable water. This aquifer subcrops beneath the glacio-fluvial sediments that underlie the lake. Nearly all residential homes around the lake, with the exception of homes in the city of Cortland, rely on domestic supply wells as a source of potable water.Oil and natural gas exploration and production have been ongoing in the Mosquito Creek Lakearea since the discovery of the historic Mecca Oil Pool in the Mississippian Berea and Cussewago Sandstones in 1860. Since the late 1970' s, the major drilling objective and zone of production is the Lower Silurian Clinton sandstone. The oil and natural gas resources of the Mosquito Creek Lake area, including reservoir pressure, production history, and engineering and abandonment practices are described in this report.The chemical and isotopic characteristics of the historic Mecca oil and natural gas are very different than those of the Clinton sandstone oil and natural gas. Gas chromatograms show that Mecca oil samples are extensively altered by biodegradation, whereas Clinton sandstone oils are not. Extensive alteration of Mecca oil is consistent with their occurrence at very shallow depths (less than 100 ft below land surface) where microbial activity can affect their composition. Also, the carbon-isotope composition of dissolved methane gas from Berea and Cussewago Sandstone water samples indicates that the gas is microbially generated, whereas the Clinton sandstone gases are thermogenically generated.Methane gas, in addition to crude oil, occurs naturally in the shallow Berea and Cussewago Sandstone aquifers in the Mosquito Creek Lake area and concentrations of dissolved methane are significant in the city of Cortland public-supply wells and in the domestic-supply wells near the southern shore of the lake. Water associated with oil and gas in the Clinton sandstone is a brine with high concentrations of chloride. Water from the Berea and Cussewago Sandstones, however, is fresh and potable. The contrasting geochemical characteristics are important for addressing water-quality issues that relate to oil and natural gas development in the Mosquito Creek area.A reexamination of the geologic framework and results of a subsurface-gas survey show that crude oil in the historic Mecca Oil Pool probably does not seep into Mosquito Creek Lake. Environmental samples show no evidence of any measurable release of oil, gas, or brine from the deeper Clinton sandstone oil and gas wells to the shallow aquifers, the lake, or lake tributaries. Brine is not associated with the hydrocarbons in the shallow Berea-Cussewago aquifer system and therefore cannot be a source of brine contamination. A mixing diagram constructed for dissolved bromide and chloride in surface water and water-supply wells shows no demonstrable mixing of these water resources with brine from the Clinton sandstone. There is some notable salinity in surface waters; however, the water is bromide poor, and a mixing diagram indicates that some local ground waters are influenced by halite solutions, presumably derived from leaching of road salt or from septic effluent.

Controlling mechanism and resulting spray characteristics of injection of fuel containing dissolved gas

NASA Astrophysics Data System (ADS)

Huang, Zhen; Shao, Yiming; Shiga, Seiichi; Nakamura, Hisao

1994-09-01

This paper presents a recent advance in the study of injection of fuel containing dissolved gas (IFCDG). Using diesel fuel containing dissolved CO2, experiments were performed under atmospheric conditions on a diesel hole-type nozzle and simple nozzles. The effects of gas concentration in the fuel, injection pressure and the nozzle L/D ratio were examined. In order to reveal the controlling mechanism of IFCDG, the orifice flow pattern, pressure characteristics and their effects were also investigated. The result shows that IFCDG can produce a parabolic-shaped spray pattern with good atomization, which suggests the existence of a new atomization mechanism. In terms of atomization, the beneficial effect of the IFCDG is obtained at the dissolved gas concentration above the transition and in the region of larger nozzle L/D ratio. However, under unfavorable conditions, IFCDG will lead to deterioration of atomization with coarse fuel droplets. It is found that the big difference of the orifice pressure characteristics caused by the variation of the nozzle L/D ratio has a dominant influence on the separation of the dissolved gas from the fuel inside the orifice and is verified to account for a dramatic change in the spray pattern and determine the effect of IFCDG. It is considered that the concept of IFCDG could be attractive in producing more efficient, clean engine and find use in a wide range of application.

Variations in Gas and Water Pulses at an Arctic Seep: Fluid Sources and Methane Transport

NASA Astrophysics Data System (ADS)

Hong, W.-L.; Torres, M. E.; Portnov, A.; Waage, M.; Haley, B.; Lepland, A.

2018-05-01

Methane fluxes into the oceans are largely dependent on the methane phase as it migrates upward through the sediments. Here we document decoupled methane transport by gaseous and aqueous phases in Storfjordrenna (offshore Svalbard) and propose a three-stage evolution model for active seepage in the region where gas hydrates are present in the shallow subsurface. In a preactive seepage stage, solute diffusion is the primary transport mechanism for methane in the dissolved phase. Fluids containing dissolved methane have high 87Sr/86Sr ratios due to silicate weathering in the microbial methanogenesis zone. During the active seepage stage, migration of gaseous methane results in near-seafloor gas hydrate formation and vigorous seafloor gas discharge with a thermogenic fingerprint. In the postactive seepage stage, the high concentration of dissolved lithium points to the contribution of a deeper-sourced aqueous fluid, which we postulate advects upward following cessation of gas discharge.

Distribution and origin of groundwater methane in the Wattenberg oil and gas field of northern Colorado.

PubMed

Li, Huishu; Carlson, Kenneth H

2014-01-01

Public concerns over potential environmental contamination associated with oil and gas well drilling and fracturing in the Wattenberg field in northeast Colorado are increasing. One of the issues of concern is the migration of oil, gas, or produced water to a groundwater aquifer resulting in contamination of drinking water. Since methane is the major component of natural gas and it can be dissolved and transported with groundwater, stray gas in aquifers has elicited attention. The initial step toward understanding the environmental impacts of oil and gas activities, such as well drilling and fracturing, is to determine the occurrence, where it is and where it came from. In this study, groundwater methane data that has been collected in response to a relatively new regulation in Colorado is analyzed. Dissolved methane was detected in 78% of groundwater wells with an average concentration of 4.0 mg/L and a range of 0-37.1 mg/L. Greater than 95% of the methane found in groundwater wells was classified as having a microbial origin, and there was minimal overlap between the C and H isotopic characterization of the produced gas and dissolved methane measured in the aquifer. Neither density of oil/gas wells nor distance to oil/gas wells had a significant impact on methane concentration suggesting other important factors were influencing methane generation and distribution. Thermogenic methane was detected in two aquifer wells indicating a potential contamination pathway from the producing formation, but microbial-origin gas was by far the predominant source of dissolved methane in the Wattenberg field.

Analytical instrument with apparatus and method for sample concentrating

DOEpatents

Zaromb, S.

1986-08-04

A system for analysis of trace concentrations of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

Analytical instrument with apparatus for sample concentrating

DOEpatents

Zaromb, Solomon

1989-01-01

A system for analysis of trace concentrations of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

Method for preconcentrating a sample for subsequent analysis

DOEpatents

Zaromb, Solomon

1990-01-01

A system for analysis of trace concentration of contaminants in air includes a portable liquid chromatograph and a preconcentrator for the contaminants to be analyzed. The preconcentrator includes a sample bag having an inlet valve and an outlet valve for collecting an air sample. When the sample is collected the sample bag is connected in series with a sorbing apparatus in a recirculation loop. The sorbing apparatus has an inner gas-permeable container containing a sorbent material and an outer gas-impermeable container. The sample is circulated through the outer container and around the inner container for trapping and preconcentrating the contaminants in the sorbent material. The sorbent material may be a liquid having the same composition as the mobile phase of the chromatograph for direct injection thereinto. Alternatively, the sorbent material may be a porous, solid body, to which mobile phase liquid is added after preconcentration of the contaminants for dissolving the contaminants, the liquid solution then being withdrawn for injection into the chromatograph.

Quantification of conservative and reactive transport using a single groundwater tracer test in a fractured media

NASA Astrophysics Data System (ADS)

Chatton, Eliot; Labasque, Thierry; Guillou, Aurélie; Béthencourt, Lorine; de La Bernardie, Jérôme; Boisson, Alexandre; Koch, Florian; Aquilina, Luc

2017-04-01

Identification of biogeochemical reactions in aquifers and determining kinetics is important for the prediction of contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for both conservative and reactive transport are essential to understand the biogeochemical reactivity at field scale. This study presents the results of a groundwater tracer test using the combined injection of dissolved conservative and reactive tracers (He, Xe, Ar, Br-, O2 and NO3-) in order to evaluate the transport properties of a fractured media in Brittany, France. Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowing a high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe) over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry was monitored through the sampling of major anions and cations, trace elements and microbiological diversity. The results show breakthrough curves allowing the combined quantification of conservative and reactive transport properties. This ongoing work is an original approach investigating the link between heterogeneity of porous media and biogeochemical reactions at field scale. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.

Evidence of Sulfate-Dependent Anaerobic Methane Oxidation within an Area Impacted by Coalbed Methane-Related Gas Migration

NASA Astrophysics Data System (ADS)

Wolfe, A. L.; Wikin, R. T.

2017-12-01

We evaluated water quality characteristics in the northern Raton Basin of Colorado and documented the response of the Poison Canyon aquifer system several years after upward migration of methane gas occurred from the deeper Vermejo Formation coalbed production zone. Over a 17-month study period, water samples were obtained from domestic water wells and monitoring wells located within the impacted area, and analyzed for 245 constituents, including organic compounds, nutrients, major and trace elements, dissolved gases, and isotopic tracers for carbon, sulfur, oxygen, and hydrogen. Multiple lines of evidence suggest that sulfate-dependent methane biodegradation, which involves the oxidation of methane (CH4) to carbon dioxide (CO2) using sulfate (SO42-) as the terminal electron acceptor, is occurring: (i) consumption of methane and sulfate and production of sulfide and bicarbonate, (ii) methane loss coupled to production of higher molecular weight (C2+) gaseous hydrocarbons, (iii) patterns of 13C enrichment and depletion in methane and dissolved inorganic carbon, and (iv) a systematic shift in sulfur and oxygen isotope ratios of sulfate, indicative of microbial sulfate reduction. Groundwater-methane attenuation is linked to the production of dissolved sulfide, and elevated dissolved sulfide concentrations represent an undesirable secondary water quality impact. The biogeochemical response of the aquifer system has not mobilized naturally occurring trace metals, including arsenic, chromium, cobalt, nickel, and lead, likely due to the microbial production of hydrogen sulfide, which favors stabilization of metals in aquifer solids.

The effect of dissolved oxygen on the susceptibility of blood.

PubMed

Berman, Avery J L; Ma, Yuhan; Hoge, Richard D; Pike, G Bruce

2016-01-01

It has been predicted that, during hyperoxia, excess O2 dissolved in arterial blood will significantly alter the blood's magnetic susceptibility. This would confound the interpretation of the hyperoxia-induced blood oxygenation level-dependent signal as arising solely from changes in deoxyhemoglobin. This study, therefore, aimed to determine how dissolved O2 affects the susceptibility of blood. We present a comprehensive model for the effect of dissolved O2 on the susceptibility of blood and compare it with another recently published model, referred to here as the ideal gas model (IGM). For validation, distilled water and samples of bovine plasma were oxygenated over a range of hyperoxic O2 concentrations and their susceptibilities were determined using multiecho gradient echo phase imaging. In distilled water and plasma, the measured changes in susceptibility were very linear, with identical slopes of 0.062 ppb/mm Hg of O2. This change was dramatically less than previously predicted using the IGM and was close to that predicted by our model. The primary source of error in the IGM is the overestimation of the volume fraction occupied by dissolved O2. Under most physiological conditions, the susceptibility of dissolved O2 can be disregarded in MRI studies employing hyperoxia. © 2015 Wiley Periodicals, Inc.

Oil recovery test using bio surfactants of indigenous bacteria in variation concentration of carbon source

NASA Astrophysics Data System (ADS)

Yudono, B.; Purwaningrum, W.; Estuningsih, S. P.; Kaffah, S.

2017-05-01

Recovery tests of crude oil by using bio surfactant of indigenous bacteria Pseudomonas peli, Pseudomonas citronellolis, Burkholderia glumae and Bacillus firmus. The bio surfactants were prepared with the variation concentrations of molasses carbon source; 0, 5, 10, 15, 20, and 25 %. The results showed that 10 g samples, which concentration 18.64% TPH could be dissolved in the bio surfactant 10%. Optimally in the molasses carbon source concentrations for each bacterium at 5, 10, 20 and 15 % with oil recovery as much as 31.92, 17.65, 22.32, and 14.38 % respectively. Oil components which extracted by bio surfactant were analyzed by using GLC (Gas Liquid Chromatography). The bio surfactants of Pseudomonas peli could dissolve oil fraction temperatures; 139.85; 144.69; 149.98; 1.55.03: 174.22 °C, Pseudomonas citronellolis could dissolve oil fraction temperatures; 139.13; 142.64;147.99; 155.03; 159.85; 164.50 °C, Burkholderia glumae could dissolve oil fraction temperatures 144.69; 149.98; 155.03; 159.85; 164.50 °C, and Bacillus firmus could dissolve oil fraction temperatures; 149.98; 155.03; 158.46; 164.50 °C.

In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

USGS Publications Warehouse

Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

2013-01-01

Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

Method of determining the extent to which a nickel structure has been attached by a fluorine-containing gas

DOEpatents

Brusie, James P.

2004-07-13

The method of determining the extent to which a nickel structure has been attacked by a halogen containing gas to which it has been exposed which comprises preparing a quantity of water substantially free from dissolved oxygen, passing ammonia gas through a cuprammonium solution to produce ammonia substantially free from oxygen, dissolving said oxygen-free ammonia in said water to produce a saturated aqueous ammonia solution free from uncombined oxygen, treating at least a portion of said nickel structure of predetermined weight with said solution to dissolve nickel compounds from the surface of said structure without dissolving an appreciable amount of said nickel and analyzing the resulting solution to determine the quantity of said nickel compounds that was associated with said said portion of said structure to determine the proportion of combined nickel in said nickel structure.

Novel Tool for Simultaneous Carbon and Nitrogen Stable Isotope Analyses in Aqueous Samples

NASA Astrophysics Data System (ADS)

Federherr, E.; Schmidt, T. C.; Cerli, C.; Kalbitz, K.; Kupka, H. J.; Lange, L.; Dunsbach, R.; Panetta, R. J.; Kasson, A.

2014-12-01

Investigation of transformation and transport processes of carbon and nitrogen in ecosystems plays an important role to understand and predict their dynamics and role in biogeochemistry. Consequently, suitable and accurate methods for concentration as well as stable isotopic composition analysis of carbon and nitrogen in waters and aqueous solutions play a significant role. Traditionally dissolved carbon and nitrogen stable isotope analysis (SIA) is performed using either offline sample preparation followed by elemental analysis isotope ratio mass spectrometry (EA/IRMS) or modified wet chemical oxidation based device coupled to IRMS. Recently we presented a high temperature combustion system (HTC), which significantly improves upon these methods for dissolved organic carbon (DOC) SIA. The analysis of δ15N of dissolved nitrogen still has large limitations. Its low concentration makes EA/IRMS laborious, time and sample consuming. Systems based on wet chemical oxidation-IRMS bare the risk of sensitivity loss as well as of fractionation due to incomplete mineralization. In addition, the high solubility of molecular nitrogen in water remains a technical challenge, as it requires additional separation steps to distinguish between physically dissolved nitrogen and bound nitrogen. Further development of our HTC system lead to the implementation of the δ15N determination which now coupled, into a novel total organic carbon (TOC) analyzing system, especially designed for SIA of both, carbon and nitrogen. Integrated, innovative purge and trap technique (peak focusing) for nitrogen with aluminosilicate adsorber and peltier element based cooling system, in combination with high injection volume (up to 3 mL) as well as favorable carrier gas flow significantly improves sensitivity. Down to 1ppm and less total nitrogen can be measured with precision of ≤ 0.5‰. To lower the background caused by physically dissolved nitrogen new, membrane-vacuum based, degasser was designed for online separation of physically dissolved nitrogen. This novel HTC system, "iso TOC cube", provides an innovative tool with large potential in investigation of biogeochemical carbon and nitrogen cycles.

Characterisation of dissolved organic compounds in hydrothermal fluids by stir bar sorptive extraction - gas chomatography - mass spectrometry. Case study: the Rainbow field (36°N, Mid-Atlantic Ridge)

PubMed Central

2012-01-01

The analysis of the dissolved organic fraction of hydrothermal fluids has been considered a real challenge due to sampling difficulties, complexity of the matrix, numerous interferences and the assumed ppb concentration levels. The present study shows, in a qualitative approach, that Stir Bar Sorptive Extraction (SBSE) followed by Thermal Desorption – Gas Chromatography – Mass Spectrometry (TD-GC-MS) is suitable for extraction of small sample volumes and detection of a wide range of volatile and semivolatile organic compounds dissolved in hydrothermal fluids. In a case study, the technique was successfully applied to fluids from the Rainbow ultramafic-hosted hydrothermal field located at 36°14’N on the Mid-Atlantic Ridge (MAR). We show that n-alkanes, mono- and poly- aromatic hydrocarbons as well as fatty acids can be easily identified and their retention times determined. Our results demonstrate the excellent repeatability of the method as well as the possibility of storing stir bars for at least three years without significant changes in the composition of the recovered organic matter. A preliminary comparative investigation of the organic composition of the Rainbow fluids showed the great potential of the method to be used for assessing intrafield variations and carrying out time series studies. All together our results demonstrate that SBSE-TD-GC-MS analyses of hydrothermal fluids will make important contributions to the understanding of geochemical processes, geomicrobiological interactions and formation of mineral deposits. PMID:23134621

Constraints of gas venting activity for the interstitial water geochemistry at the shallow gas hydrate site, eastern margin of the Japan Sea; results from high resolution time-series fluid sampling by OsmoSampler

NASA Astrophysics Data System (ADS)

Owari, S.; Tomaru, H.; Matsumoto, R.

2016-12-01

We have conducted ROV researches in the eastern margin of the Japan Sea where active gas venting and outcropping of gas hydrates were observed near the seafloor and have found the strength and location of venting had changed within a few days. These observations indicate the seafloor environments with the shallow gas hydrate system could have changed for short period compared to a geological time scale. We have applied a long-term osmotic fluid sampling system "OsmoSampler" on the active gas hydrate system for one year in order to document how the gas venting and gas hydrate activity have changed the geochemical environments near the seafloor. All the major ion concentrations in the interstitial water show synchronous increase and decrease repeatedly in three to five days, reflecting the incorporation and release of fresh water in gas hydrates in response to the gas concentration change near the sampling site. Dissolved methane concentration increases rapidly and excessively (over several mM) in the first 40 days corresponding to the active gas venting. The increases of methane concentration are often associated with high ion concentration during high water pressure period, indicating excess gas release from shallow gas pockets. Contrarily, enhanced gas hydrate growth may plug the fluid-gas paths in shallow sediment, reducing gas hydrate formation due to the decrease of methane flux. This study was conducted under the commission from AIST as a part of the methane hydrate research project funded by METI (the Ministry of Economy, Trade and Industry, Japan).

Dissolved methane in groundwater, Upper Delaware River Basin, Pennsylvania and New York, 2007-12

USGS Publications Warehouse

Kappel, William M.

2013-01-01

The prospect of natural gas development from the Marcellus and Utica Shales has raised concerns about freshwater aquifers being vulnerable to contamination. Well owners are asking questions about subsurface methane, such as, “Does my well water have methane and is it safe to drink the water?” and “Is my well system at risk of an explosion hazard associated with a combustible gas like methane in groundwater?” This newfound awareness of methane contamination of water wells by stray gas migration is based upon studies such as Molofsky and others (2011) who document the widespread natural occurrence of methane in drinking-water wells in Susquehanna County, Pennsylvania. In the same county, Osborn and others (2011) identified elevated methane concentrations in selected drinking-water wells in the vicinity of Marcellus Shale gas-development activities, although pre-development groundwater samples were not available for comparison. A compilation of dissolved methane concentrations in groundwater for New York State was published by Kappel and Nystrom (2012). Recent work documenting the occurrence and distribution of methane in groundwater was completed in southern Sullivan County, Pennsylvania (Sloto, 2013). Additional work is ongoing with respect to monitoring for stray gases in groundwater (Jackson and others, 2013). These studies and their results indicate the importance of collecting baseline or pre-development data. While such data are being collected in some areas, published data on methane in groundwater are sparse in the Upper Delaware River Basin of Pennsylvania, New York, and New Jersey. To manage drinking-water resources in areas of gas-well drilling and hydraulic fracturing in the Upper Delaware River Basin, the natural occurrence of methane in the tri-state aquifers needs to be documented. The purpose of this report is to present data on dissolved methane concentrations in the groundwater in the Upper Delaware River Basin. The scope is restricted to data for Pennsylvania and New York, no U.S. Geological Survey (USGS) methane analyses are presently available for northwestern New Jersey.

Fundamental Study on the Dynamics of Heterogeneity-Enhanced CO2 Gas Evolution in the Shallow Subsurface During Possible Leakage from Deep Geologic Storage Sites

NASA Astrophysics Data System (ADS)

Plampin, M. R.; Lassen, R. N.; Sakaki, T.; Pawar, R.; Jensen, K.; Illangasekare, T. H.

2013-12-01

A concern for geologic carbon sequestration is the potential for CO2 stored in deep geologic formations to leak upward into shallow freshwater aquifers where it can have potentially detrimental impacts to the environment and human health. Understanding the mechanisms of CO2 exsolution, migration and accumulation (collectively referred to as 'gas evolution') in the shallow subsurface is critical to predict and mitigate the environmental impacts. During leakage, CO2 can move either as free-phase or as a dissolved component of formation brine. CO2 dissolved in brine may travel upward into shallow freshwater systems, and the gas may be released from solution. In the shallow aquifer, the exsolved gas may accumulate near interfaces between soil types, and/or create flow paths that allow the gas to escape through the vadose zone to the atmosphere. The process of gas evolution in the shallow subsurface is controlled by various factors, including temperature, dissolved CO2 concentration, water pressure, background water flow rate, and geologic heterogeneity. However, the conditions under which heterogeneity controls gas phase evolution have not yet been precisely defined and can therefore not yet be incorporated into models used for environmental risk assessment. The primary goal of this study is to conduct controlled laboratory experiments to help fill this knowledge gap. With this as a goal, a series of intermediate-scale laboratory experiments were conducted to observe CO2 gas evolution in porous media at multiple scales. Deionized water was saturated with dissolved CO2 gas under a specified pressure (the saturation pressure) before being injected at a constant volumetric flow rate into the bottom of a 1.7 meter-tall by 5.7 centimeter-diameter column or a 2.4 meter-tall by 40 centimeter-wide column that were both filled with sand in various heterogeneous packing configurations. Both test systems were initially saturated with fresh water and instrumented with soil moisture sensors to monitor the evolution of gas phase through time by measuring the average water content in small sampling volumes of soil. Tensiometers allowed for observation of water pressure through space and time in the test systems, and a computer-interfaced electronic scale continuously monitored the outflow of water from the top of the two test columns. Several packing configurations with five different types of sands were used in order to test the effects of various pore size contrasts and interface shapes on the evolution of the gas phase near soil texture transitions in the heterogeneous packings. Results indicate that: (1) heterogeneity affects gas phase evolution patterns within a predictable range of conditions quantified by the newly introduced term 'oversaturation,' (2) soil transition interfaces where less permeable material overlies more permeable material have a much more pronounced effect on gas evolution than interfaces with opposite orientations, and (3) anticlines (or stratigraphic traps) cause significantly greater gas accumulation than horizontal interfaces. Further work is underway to apply these findings to more realistic, two-dimensional scenarios, and to assess how well existing numerical models can capture these processes.

Effect of phytoremediation on concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site, Charleston, South Carolina, USA, 1998–2014

USGS Publications Warehouse

Landmeyer, James E.; Effinger, Thomas N.

2016-01-01

Concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site near Charleston, South Carolina, USA, have been monitored since the installation of a phytoremediation system of hybrid poplar trees in 1998. Between 2000 and 2014, the concentrations of benzene, toluene, and naphthalene (BT&N) in groundwater in the planted area have decreased. For example, in the monitoring well containing the highest concentrations of BT&N, benzene concentrations decreased from 10,200 µg/L to less than 4000 µg/L, toluene concentrations decreased from 2420 µg/L to less than 20 µg/L, and naphthalene concentrations decreased from 6840 µg/L to less than 3000 µg/L. Concentrations of BT&N in groundwater in all wells were observed to be lower during the summer months relative to the winter months of a particular year during the first few years after installing the phytoremediation system, most likely due to increased transpiration and contaminant uptake by the hybrid poplar trees during the warm summer months; this pathway of uptake by trees was confirmed by the detection of benzene, toluene, and naphthalene in trees during sampling events in 2002, and later in the study in 2012. These data suggest that the phytoremediation system affects the groundwater contaminants on a seasonal basis and, over multiple years, has resulted in a cumulative decrease in dissolved-phase contaminant concentrations in groundwater. The removal of dissolved organic contaminants from the aquifer has resulted in a lower demand on dissolved oxygen supplied by recharge and, as a result, the redox status of the groundwater has changed from anoxic to oxic conditions. This study provides much needed information for water managers and other scientists on the viability of the long-term effectiveness of phytoremediation in decreasing groundwater contaminants and increasing dissolved oxygen at sites contaminated by benzene, toluene, and naphthalene.

Gas/liquid sensing via chemotaxis of Euglena cells confined in an isolated micro-aquarium.

PubMed

Ozasa, Kazunari; Lee, Jeesoo; Song, Simon; Hara, Masahiko; Maeda, Mizuo

2013-10-21

We demonstrate on-chip gas/liquid sensing by using the chemotaxis of live bacteria (Euglena gracilis) confined in an isolated micro-aquarium, and gas/liquid permeation through porous polydimethylsiloxane (PDMS). The sensing chip consisted of one closed micro-aquarium and two separated bypass microchannels along the perimeter of the micro-aquarium. Test gas/liquid and reference samples were introduced into the two individual microchannels separately, and the gas/liquid permeated through the PDMS walls and dissolved in the micro-aquarium water, resulting in a chemical concentration gradient in the micro-aquarium. By employing the closed micro-aquarium isolated from sample flows, we succeeded in measuring the chemotaxis of Euglena for a gas substance quantitatively, which cannot be achieved with the conventional flow-type or hydro-gel-type microfluidic devices. We found positive (negative) chemotaxis for CO2 concentrations below (above) 15%, with 64 ppm as the minimum concentration affecting the cells. We also observed chemotaxis for ethanol and H2O2. By supplying culture medium via the microchannels, the Euglena culture remained alive for more than 2 months. The sensing chip is thus useful for culturing cells and using them for environmental toxicity/nutrition studies by monitoring their motion.

Regional Analysis of the Effects of Oil and Gas Development on Groundwater Resources in California

NASA Astrophysics Data System (ADS)

Landon, M. K.; McMahon, P. B.; Kulongoski, J. T.; Ball, L. B.; Gillespie, J. M.; Shimabukuro, D.; Taylor, K. A.

2016-12-01

The California State Water Resources Control Board is collaborating with the U.S. Geological Survey to implement a Regional Monitoring Program (RMP) to assess potential interactions between oil/gas stimulation treatment and groundwater resources. The effects of stimulation on groundwater resources will be difficult to distinguish from the effects of other past or present components of oil and gas development. As a result, the RMP is designed to provide an overall assessment of the effects of oil and gas development on groundwater quality. During 2016-17, the study is focused on selected priority oilfields in the eastern and western portions of the San Joaquin Valley in Kern County to: (1) produce three-dimensional (3D) salinity maps, (2) characterize the chemical composition of groundwater and produced water, and (3) identify the extent to which fluids from oil and gas development may be moving into protected (total dissolved solids less than 10,000 milligrams per liter) groundwater at regional scales. Analysis of available salinity data near oil/gas fields indicates there are regional patterns to salinity depth profiles; however, data gaps between the depths of water and oil/gas wells are common. These results provide a foundation for more detailed oilfield-scale salinity mapping, which includes geophysical methods (borehole, surface, and airborne) to fill data gaps. The RMP sampling-well networks are designed to evaluate groundwater quality along transects from oil/gas fields into adjacent aquifers and consist of existing wells supplemented by monitoring-well installation in priority locations identified by using 3D visualization of hydrogeologic data. The analytes include constituents with different transport characteristics such as dissolved gases, inorganic components (brines), and petroleum compounds. Analytes were selected because of their potential usefulness for understanding processes and pathways by which fluids from oilfield sources reach groundwater.

In search of thermogenic methane in groundwater in the Netherlands, with emphasis on the location of a historic gas well blowout

NASA Astrophysics Data System (ADS)

Schout, G.; Griffioen, J.; Hassanizadeh, S. M.; Hartog, N.

2017-12-01

Similar to the US, the Netherlands has a long history of oil & gas production, with around 2500 onshore hydrocarbon wells drilled since the late 1930s. While conventional reserves are diminishing, a governmental moratorium was put in place on shale gas exploration and production until 2023, in part due to concerns about its effects on groundwater quality. To investigate the industry's historic and potential future impact on groundwater quality in the country, a study was carried out to assess i) baseline methane concentrations and origin ii) the natural connectivity of deeper gas-bearing layers with the shallower groundwater systems. Through datamining, a dataset consisting of 12,200 groundwater analyses with methane concentrations was assembled. Furthermore, 25 additional samples were collected at targeted locations and analysed for dissolved gas molecular and isotopic composition. Methane concentrations are positively skewed with median, mean and maximum concentrations of 0.28, 2.17 and 120 mg/L, respectively. No correlation between methane concentrations and distance to hydrocarbon wells or faults is observed. In general, concentrations cannot be readily explained by factors such as the depth, geographic location, host formation and depositional environment. Thermogenic methane was first encountered at several hundred meters depth, below thick successions of marine Paleogene and Neogene clays that are present throughout the country and impede vertical flow. All methane encountered above these formations was found to be biogenic in origin, with one notable exception - a sample taken at the site of a catastrophic gas well blowout that occurred in 1965 near the village of Sleen. Combined, these findings suggest that thermogenic methane does not naturally occur in Dutch shallow groundwater and its presence can be used as an indicator of anthropogenic gas leakage. The unique Sleen blowout site was selected for a detailed investigation of the long-term effects of uncontrolled gas leakage on groundwater chemistry. Methane concentrations up to 45 mg/L were observed and the distribution pattern suggests on-going leakage, 50 years after the events. Results also show that anaerobic oxidation of methane plays a major role in controlling the spread of dissolved methane.

Redox controls on methane formation, migration and fate in shallow aquifers

NASA Astrophysics Data System (ADS)

Humez, Pauline; Mayer, Bernhard; Nightingale, Michael; Becker, Veith; Kingston, Andrew; Taylor, Stephen; Bayegnak, Guy; Millot, Romain; Kloppmann, Wolfram

2016-07-01

Development of unconventional energy resources such as shale gas and coalbed methane has generated some public concern with regard to the protection of groundwater and surface water resources from leakage of stray gas from the deep subsurface. In terms of environmental impact to and risk assessment of shallow groundwater resources, the ultimate challenge is to distinguish (a) natural in situ production of biogenic methane, (b) biogenic or thermogenic methane migration into shallow aquifers due to natural causes, and (c) thermogenic methane migration from deep sources due to human activities associated with the exploitation of conventional or unconventional oil and gas resources. This study combines aqueous and gas (dissolved and free) geochemical and isotope data from 372 groundwater samples obtained from 186 monitoring wells of the provincial Groundwater Observation Well Network (GOWN) in Alberta (Canada), a province with a long record of conventional and unconventional hydrocarbon exploration. We investigated whether methane occurring in shallow groundwater formed in situ, or whether it migrated into the shallow aquifers from elsewhere in the stratigraphic column. It was found that methane is ubiquitous in groundwater in Alberta and is predominantly of biogenic origin. The highest concentrations of biogenic methane (> 0.01 mM or > 0.2 mgL-1), characterized by δ13CCH4 values < -55 ‰, occurred in anoxic Na-Cl, Na-HCO3, and Na-HCO3-Cl type groundwaters with negligible concentrations of nitrate and sulfate suggesting that methane was formed in situ under methanogenic conditions for 39.1 % of the samples. In only a few cases (3.7 %) was methane of biogenic origin found in more oxidizing shallow aquifer portions suggesting limited upward migration from deeper methanogenic aquifers. Of the samples, 14.1 % contained methane with δ13CCH4 values > -54 ‰, potentially suggesting a thermogenic origin, but aqueous and isotope geochemistry data revealed that the elevated δ13CCH4 values were caused by microbial oxidation of biogenic methane or post-sampling degradation of low CH4 content samples rather than migration of deep thermogenic gas. A significant number of samples (39.2 %) contained methane with predominantly biogenic C isotope ratios (δ13CCH4 < -55 ‰) accompanied by elevated concentrations of ethane and sometimes trace concentrations of propane. These gases, observed in 28.1 % of the samples, bearing both biogenic (δ13C) and thermogenic (presence of C3) characteristics, are most likely derived from shallow coal seams that are prevalent in the Cretaceous Horseshoe Canyon and neighboring formations in which some of the groundwater wells are completed. The remaining 3.7 % of samples were not assigned because of conflicting parameters in the data sets or between replicates samples. Hence, despite quite variable gas concentrations and a wide range of δ13CCH4 values in baseline groundwater samples, we found no conclusive evidence for deep thermogenic gas migration into shallow aquifers either naturally or via anthropogenically induced pathways in this baseline groundwater survey. This study shows that the combined interpretation of aqueous geochemistry data in concert with chemical and isotopic compositions of dissolved and/or free gas can yield unprecedented insights into formation and potential migration of methane in shallow groundwater. This enables the assessment of cross-formational methane migration and provides an understanding of alkane gas sources and pathways necessary for a stringent baseline definition in the context of current and future unconventional hydrocarbon exploration and exploitation.

In Situ Groundwater Denitrification in the Riparian Zone of a Short-Rotation Woody Crop Experimental Watershed

NASA Astrophysics Data System (ADS)

Jeffers, J. B.; Jackson, C. R.; Rau, B.; Pringle, C. M.; Matteson, C.

2017-12-01

The southeastern United States has potential to become a major producer of short rotation woody crops (SRWC) for the production of biofuels, but this will require converting to more intensive forest management practices that will increase nitrate (NO3-) loading and alter nitrogen cycling in nearby freshwater ecosystems. Water quality monitoring in an experimental short-rotation woody crop watershed in the Coastal Plain of South Carolina has shown increased concentrations of NO3- in groundwater but no evidence of increased NO3- in riparian groundwater or surface waters. Forested riparian areas established as streamside management zones (SMZ) are known to act as buffers to surface water bodies by mitigating nutrients. The objectives of this study were to quantify denitrification by measuring dinitrogen (N2) and nitrous oxide (N2O) concentrations along groundwater flow paths and analyze relationships between denitrification estimates, nutrients, and water chemistry parameters. A network of piezometers has been established in the Fourmile Experimental Watershed at the Department of Energy - Savannah River Site. Water samples were collected monthly and were analyzed for concentrations of nutrients (temperature, specific conductivity, dissolved oxygen, pH, dissolved organic carbon) and dissolved gases (N2, Ar, N2O). Preliminary data showed greater dissolved N2O concentrations than dissolved N2 concentrations in groundwater. The ratios of N2O to combined end products of denitrification (N2O / N2O+N2) ranged from 0.33 to 0.99. Mean N2O+N2 concentrations were greater in groundwater samples in the SRWC plot and along the SMZ boundary than along the ephemeral stream within the riparian zone. Correlations between water chemistry parameters and N2 concentrations are indicative of known biogeochemical driving factors of denitrification. Continued monthly sampling will be coupled with analysis of nutrient concentrations (NO3-, NH4+, TN) to help determine transport and processing of NO3- and production of dissolved gases within the groundwater system. Use of hydrologic models combined with dissolved gas concentrations will provide estimates of denitrification rates and indirect gaseous emissions.

An assessment of the liquid-gas partitioning behavior of major wastewater odorants using two comparative experimental approaches: liquid sample-based vaporization vs. impinger-based dynamic headspace extraction into sorbent tubes.

PubMed

Iqbal, Mohammad Asif; Kim, Ki-Hyun; Szulejko, Jan E; Cho, Jinwoo

2014-01-01

The gas-liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RFvap/RFimp) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling.

Argonne Geothermal Geochemical Database v2.0

DOE Data Explorer

Harto, Christopher

2013-05-22

A database of geochemical data from potential geothermal sources aggregated from multiple sources as of March 2010. The database contains fields for the location, depth, temperature, pH, total dissolved solids concentration, chemical composition, and date of sampling. A separate tab contains data on non-condensible gas compositions. The database contains records for over 50,000 wells, although many entries are incomplete. Current versions of source documentation are listed in the dataset.

Physicochemical impacts associated with natural gas development on methanogenesis in deep sand aquifers.

PubMed

Katayama, Taiki; Yoshioka, Hideyoshi; Muramoto, Yoshiyuki; Usami, Jun; Fujiwara, Kazuhiro; Yoshida, Satoshi; Kamagata, Yoichi; Sakata, Susumu

2015-02-01

The Minami-Kanto gas field, where gases are dissolved in formation water, is a potential analogue for a marine gas hydrate area because both areas are characterized by the accumulation of microbial methane in marine turbidite sand layers interbedded with mud layers. This study examined the physicochemical impacts associated with natural gas production and well drilling on the methanogenic activity and composition in this gas field. Twenty-four gas-associated formation water samples were collected from confined sand aquifers through production wells. The stable isotopic compositions of methane in the gases indicated their origin to be biogenic via the carbonate reduction pathway. Consistent with this classification, methanogenic activity measurements using radiotracers, culturing experiments and molecular analysis of formation water samples indicated the predominance of hydrogenotrophic methanogenesis. The cultivation of water samples amended only with methanogenic substrates resulted in significant increases in microbial cells along with high-yield methane production, indicating the restricted availability of substrates in the aquifers. Hydrogenotrophic methanogenic activity increased with increasing natural gas production from the corresponding wells, suggesting that the flux of substrates from organic-rich mudstones to adjacent sand aquifers is enhanced by the decrease in fluid pressure in sand layers associated with natural gas/water production. The transient predominance of methylotrophic methanogens, observed for a few years after well drilling, also suggested the stimulation of the methanogens by the exposure of unutilized organic matter through well drilling. These results provide an insight into the physicochemical impacts on the methanogenic activity in biogenic gas deposits including marine gas hydrates.

Physicochemical impacts associated with natural gas development on methanogenesis in deep sand aquifers

PubMed Central

Katayama, Taiki; Yoshioka, Hideyoshi; Muramoto, Yoshiyuki; Usami, Jun; Fujiwara, Kazuhiro; Yoshida, Satoshi; Kamagata, Yoichi; Sakata, Susumu

2015-01-01

The Minami-Kanto gas field, where gases are dissolved in formation water, is a potential analogue for a marine gas hydrate area because both areas are characterized by the accumulation of microbial methane in marine turbidite sand layers interbedded with mud layers. This study examined the physicochemical impacts associated with natural gas production and well drilling on the methanogenic activity and composition in this gas field. Twenty-four gas-associated formation water samples were collected from confined sand aquifers through production wells. The stable isotopic compositions of methane in the gases indicated their origin to be biogenic via the carbonate reduction pathway. Consistent with this classification, methanogenic activity measurements using radiotracers, culturing experiments and molecular analysis of formation water samples indicated the predominance of hydrogenotrophic methanogenesis. The cultivation of water samples amended only with methanogenic substrates resulted in significant increases in microbial cells along with high-yield methane production, indicating the restricted availability of substrates in the aquifers. Hydrogenotrophic methanogenic activity increased with increasing natural gas production from the corresponding wells, suggesting that the flux of substrates from organic-rich mudstones to adjacent sand aquifers is enhanced by the decrease in fluid pressure in sand layers associated with natural gas/water production. The transient predominance of methylotrophic methanogens, observed for a few years after well drilling, also suggested the stimulation of the methanogens by the exposure of unutilized organic matter through well drilling. These results provide an insight into the physicochemical impacts on the methanogenic activity in biogenic gas deposits including marine gas hydrates. PMID:25105906

Evaluation of potential gas clogging associated with managed aquifer recharge from a spreading basin, southwestern Utah, U.S.A.

USGS Publications Warehouse

Heilweil, Victor M.; Marston, Thomas

2013-01-01

Sand Hollow Reservoir in southwestern Utah, USA, is operated for both surface-water storage and managed aquifer recharge via infiltration from surface basin spreading to the underlying Navajo Sandstone. The total volume of estimated recharge from 2002 through 2011 was 131 Mm3., resulting in groundwater levels rising as much as 40 m. Hydraulic and hydrochemical data from the reservoir and various monitoring wells in Sand Hollow were used to evaluate the timing and location or reservoir recharge moving through the aquifer, along either potential clogging from trapped gases in pore throats, siltation, or algal mats. Several hyrdochemical tracers indicated this recharge had arrived at four monitoring wells located within about 300 m of the reservoir by 2012. At these wells, peak total dissolved-gas pressures exceeded two atmospheres (>1,500 mm mercury) and dissolved oxygen approached three times atmospherically equilibrated concentrations (>25 mg/L). these field parameters indicate that large amounts of gas trapped in pore spaces beneath the water table have dissolved. Lesser but notable increases in these dissolved-gas parameters (without increases in other indicators such as chloride-to-bromide ratios) at monitoring wells farther away (>300 m) indicate moderate amounts of in-situ sir entrapment and dissolution caused by the rise in regional groundwater levels. This is confirmed by hydrochemical difference between these sites and wells closer to the reservoir where recharge had already arrived. As the reservoir was being filled by 2002, managed aquifer recharge rates were initially very high (1.5 x 10-4 cm/s) with the vadose zone becoming saturated beneath and surrounding the reservoir. These rates declined to less than 3.5 x 10-6 cm/s during 2008. The 2002-08 decrease was likely associated with a declining regional hydraulic gradient and clogging. Increasing recharge rates during mid-2009 through 2010 may have been partly caused by dissolution of air bubbles initially entrapped in the aquifer matrix. Theoretical gas dissolution rates, coupled with field evidence of a decline iin total dissolved-gas pressure and dissolved oxygen from nearby monitoring wells, support the timing of this gas dissipation.

A Portable and Autonomous Mass Spectrometric System for On-Site Environmental Gas Analysis.

PubMed

Brennwald, Matthias S; Schmidt, Mark; Oser, Julian; Kipfer, Rolf

2016-12-20

We developed a portable mass spectrometric system ("miniRuedi") for quantificaton of the partial pressures of He, Ne (in dry gas), Ar, Kr, N 2 , O 2 , CO 2 , and CH 4 in gaseous and aqueous matrices in environmental systems with an analytical uncertainty of 1-3%. The miniRuedi does not require any purification or other preparation of the sampled gases and therefore allows maintenance-free and autonomous operation. The apparatus is most suitable for on-site gas analysis during field work and at remote locations due to its small size (60 cm × 40 cm × 14 cm), low weight (13 kg), and low power consumption (50 W). The gases are continuously sampled and transferred through a capillary pressure reduction system into a vacuum chamber, where they are analyzed using a quadrupole mass spectrometer with a time resolution of ≲1 min. The low gas consumption rate (<0.1 mL/min) minimizes interference with the natural mass balance of gases in environmental systems, and allows the unbiased quantification of dissolved-gas concentrations in water by gas/water equilibration using membrane contractors (gas-equilibrium membrane-inlet mass spectrometry, GE-MIMS). The performance of the miniRuedi is demonstrated in laboratory and field tests, and its utility is illustrated in field applications related to soil-gas formation, lake/atmosphere gas exchange, and seafloor gas emanations.

Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

NASA Astrophysics Data System (ADS)

Rivard, Christine; Bordeleau, Geneviève; Lavoie, Denis; Lefebvre, René; Malet, Xavier

2018-03-01

Dissolved methane concentrations in shallow groundwater are known to vary both spatially and temporally. The extent of these variations is poorly documented although this knowledge is critical for distinguishing natural fluctuations from anthropogenic impacts stemming from oil and gas activities. This issue was addressed as part of a groundwater research project aiming to assess the risk of shale gas development for groundwater quality over a 500-km2 area in the St. Lawrence Lowlands (Quebec, Canada). A specific study was carried out to define the natural variability of methane concentrations and carbon and hydrogen isotope ratios in groundwater, as dissolved methane is naturally ubiquitous in aquifers of this area. Monitoring was carried out over a period of up to 2.5 years in seven monitoring wells. Results showed that for a given well, using the same sampling depth and technique, methane concentrations can vary over time from 2.5 to 6 times relative to the lowest recorded value. Methane isotopic composition, which is a useful tool to distinguish gas origin, was found to be stable for most wells, but varied significantly over time in the two wells where methane concentrations are the lowest. The use of concentration ratios, as well as isotopic composition of methane and dissolved inorganic carbon (DIC), helped unravel the processes responsible for these variations. This study indicates that both methane concentrations and isotopic composition, as well as DIC isotopes, should be regularly monitored over at least 1 year to establish their potential natural variations prior to hydrocarbon development.

Greenhouse Gas Dynamics in Streams and Riparian Floodplains located within Forested Landscapes of the US Northeast: Impact of Key Floodplain Geomorphic Features on Greenhouse Gas Production in a Forested Watershed in Northern New York State, USA.

NASA Astrophysics Data System (ADS)

Serchan, S. P.; Vidon, P.

2015-12-01

This study measured dissolved greenhouse gas (GHG) concentrations in interstitial water and stream across various "hotspots" in headwater catchments of Archer Creek watershed, New York, USA. Results indicated that stream water was hyper saturated with methane (CH4), and moderately saturated with carbon dioxide (CO2), and nitrous oxide (N2O). The values of dissolved CO2 (88.3 μmol/L), dissolved CH4 (1.2 μmol/L), and dissolved N2O (0.02 μmol/L) found in the stream were 5.8, 432, and 2.3 times in excess of atmospheric equilibrium, respectively. Results of dissolved GHG measured in interstitial water across various sites: riparian dry (RZ-Dry), riparian wet (RZ-Wet), riparian mucky (RZ-Mucky), pool with fine textured bed sediments (IS-fine-sedpool), pool with coarse textured bed sediments (IS-coarse-sed-pool), and riffles (Riffle) indicated high variations in the degree of saturation of all three GHG. RZ-Mucky, RZ-Wet, and IS-fine-sedpool sites were hotspots of CH4 and CO2 relative to other sites. RZ-Dry sites were hotspots of N2O. Multiple linear regression models indicated that dissolved oxygen (D.O.) and dissolved organic carbon (DOC) influenced dissolved CO2 and CH4 at most of the sites. Relationships between dissolved N2O and predictor variables were highly variable across all sites. Patterns of dissolved N2O in relatively oxic RZ-Dry sites (D.O. 5.3 mg/L) were positively correlated with nitrate (NO3) indicating nitrification as a dominant process in N2O production. In contrast, patterns of dissolved N2O were positively correlated with ammonium (NH4+) at RZ-Wet and RZ-Mucky sites where concentrations of D.O. were significantly lower compared to other sites.

Determination of polar organic solutes in oil-shale retort water

USGS Publications Warehouse

Leenheer, J.A.; Noyes, T.I.; Stuber, H.A.

1982-01-01

A variety of analytical methods were used to quantitatively determine polar organic solutes in process retort water and a gas-condensate retort water produced in a modified in situ oil-shale retort. Specific compounds accounting for 50% of the dissolved organic carbon were identified in both retort waters. In the process water, 42% of the dissolved organic carbon consisted of a homologous series of fatty acids from C2 to C10. Dissolved organic carbon percentages for other identified compound classes were as follows: aliphatic dicarboxylic acids, 1.4%; phenols, 2.2%; hydroxypyridines, 1.1%; aliphatic amides, 1.2%. In the gas-condensate retort water, aromatic amines were most abundant at 19.3% of the dissolved organic carbon, followed by phenols (17.8%), nitriles (4.3%), aliphatic alcohols (3.5%), aliphatic ketones (2.4%), and lactones (1.3%). Steam-volatile organic solutes were enriched in the gas-condensate retort water, whereas nonvolatile acids and polyfunctional neutral compounds were predominant organic constituents of the process retort water.

Ground-water quality of the Upper Floridan Aquifer near an abandoned manufactured gas plant in Albany, Georgia

USGS Publications Warehouse

Chapman, M.J.

1993-01-01

Manufactured gas plants produced gas for heating and lighting in the United States from as early as 1816 into the 1960's. By-products including, but not limited to, oil residues and tar, were generated during the gas-manufacturing process. Organic compounds (hydrocarbons) were detected in water in the upper water-bearing zone of the Upper Floridan aquifer near an abandoned manufactured gas plant (MGP) in Albany, Georgia, during an earlier investigation in 1990. Chemical analyses of ground-water samples collected from five existing monitoring wells in 1991 verify the presence of hydrocarbons and metals in the upper water-beating zone of the Upper Floridan aquifer. One well was drilled into the lower water-beating zone of the Upper Floridan aquifer in 1991 for water-quality sampling and water-level monitoring. Analyses of ground water sampled from this well did not show evidence of benzene, toluene, xylene, napthalene, acenaphthlene, or other related compounds detected in the upper water-bearing zone in the study area. Low concentrations of tetrachloroethane, trichloromethane, and l,2-cisdichloroethene were detected in a water sample from the deeper well; however, these compounds were not detected in the upper water-bearing zone in the study area. Inorganic constituent concentrations also were substantially lower in the deeper well. Overall, ground water sampled from the lower water-bearing zone had lower specific conductance and alkalinity; and lower concentrations of dissolved solids, iron, and manganese compared to ground water sampled from the upper water-bearing zone. Water levels for the upper and lower water-bearing zones were similar throughout the study period.

Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange nuclear magnetic resonance

NASA Technical Reports Server (NTRS)

Butler, J. P.; Mair, R. W.; Hoffmann, D.; Hrovat, M. I.; Rogers, R. A.; Topulos, G. P.; Walsworth, R. L.; Patz, S.

2002-01-01

We demonstrate a minimally invasive nuclear magnetic resonance (NMR) technique that enables determination of the surface-area-to-volume ratio (S/V) of soft porous materials from measurements of the diffusive exchange of laser-polarized 129Xe between gas in the pore space and 129Xe dissolved in the solid phase. We apply this NMR technique to porous polymer samples and find approximate agreement with destructive stereological measurements of S/V obtained with optical confocal microscopy. Potential applications of laser-polarized xenon interphase exchange NMR include measurements of in vivo lung function in humans and characterization of gas chromatography columns.

A Ni-Doped Carbon Nanotube Sensor for Detecting Oil-Dissolved Gases in Transformers

PubMed Central

Lu, Jia; Zhang, Xiaoxing; Wu, Xiaoqing; Dai, Ziqiang; Zhang, Jinbin

2015-01-01

C2H2, C2H4, and C2H6 are important oil-dissolved gases in power transformers. Detection of the composition and content of oil-dissolved gases in transformers is very significant in the diagnosis and assessment of the state of transformer operations. The commonly used oil-gas analysis methods have many disadvantages, so this paper proposes a Ni-doped carbon nanotube (Ni-CNT) gas sensor to effectively detect oil-dissolved gases in a transformer. The gas-sensing properties of the sensor to C2H2, C2H4, and C2H6 were studied using the test device. Based on the density functional theory (DFT) the adsorption behaviors of the three gases on intrinsic carbon nanotubes (CNTs) and Ni-CNTs were calculated. The adsorption energy, charge transfer, and molecular frontier orbital of the adsorption system were also analyzed. Results showed that the sensitivity of the CNT sensor to the three kinds of gases was in the following order: C2H2 > C2H4 > C2H6. Moreover, the doped Ni improved the sensor response, and the sensor response and gas concentration have a good linear relationship. PMID:26066989

A Ni-Doped Carbon Nanotube Sensor for Detecting Oil-Dissolved Gases in Transformers.

PubMed

Lu, Jia; Zhang, Xiaoxing; Wu, Xiaoqing; Dai, Ziqiang; Zhang, Jinbin

2015-06-09

C2H2, C2H4, and C2H6 are important oil-dissolved gases in power transformers. Detection of the composition and content of oil-dissolved gases in transformers is very significant in the diagnosis and assessment of the state of transformer operations. The commonly used oil-gas analysis methods have many disadvantages, so this paper proposes a Ni-doped carbon nanotube (Ni-CNT) gas sensor to effectively detect oil-dissolved gases in a transformer. The gas-sensing properties of the sensor to C2H2, C2H4, and C2H6 were studied using the test device. Based on the density functional theory (DFT) the adsorption behaviors of the three gases on intrinsic carbon nanotubes (CNTs) and Ni-CNTs were calculated. The adsorption energy, charge transfer, and molecular frontier orbital of the adsorption system were also analyzed. Results showed that the sensitivity of the CNT sensor to the three kinds of gases was in the following order: C2H2 > C2H4 > C2H6. Moreover, the doped Ni improved the sensor response, and the sensor response and gas concentration have a good linear relationship.

Chemical characterization of fractions of dissolved humic substances from a marginal sea—a case from the Southern Yellow Sea

NASA Astrophysics Data System (ADS)

Zhang, Yaoling; Yang, Keli; Du, Jinzhou; Zhang, Fenfen; Dong, Yaping; Li, Wu

2018-03-01

Marine dissolved organic matter (DOM) is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances (DHS) were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids (FAs), humic acids (HAs) and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy (FTIR), 13C cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.

Transport of dissolved gases through unsaturated porous media

NASA Astrophysics Data System (ADS)

Maryshev, B. S.

2017-06-01

The natural porous media (e.g. soil, sand, peat etc.) usually are partially saturated by groundwater. The saturation of soil depends on hydrostatic pressure which is linearly increased with depth. Often some gases (e.g. nitrogen, oxygen, carbon dioxide, methane etc.) are dissolved into the groundwater. The solubility of gases is very small because of that two assumptions is applied: I. The concentration of gas is equal to solubility, II. Solubility depends only on pressure (for isothermal systems). In this way some part of dissolved gas transfers from the solution to the bubble phase. The gas bubbles are immovably trapped in a porous matrix by surface-tension forces and the dominant mechanism of transport of gas mass becomes the diffusion of gas molecules through the liquid. If the value of water content is small then the transport of gas becomes slow and gas accumulates into bubble phase. The presence of bubble phase additionally decreases the water content and slows down the transport. As result the significant mass of gas should be accumulated into the massif of porous media. We derive the transport equations and find the solution which is demonstrated the accumulation of gases. The influence of saturation, porosity and filtration velocity to accumulation process is investigated and discussed.

Field Degassing as a New Sampling Method for 14C Analyses in Old Groundwater

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

Yokochi, Reika; Bernier, Ryan; Purtschert, Roland

Radiocarbon ( 14C) activity in groundwater can be used to determine subsurface residence time up to ~40 kyr, providing crucial information on dynamic properties of groundwater and on paleoclimate. However, commonly applied sampling methods for dissolved inorganic carbon (DIC- 14C) are prone to low level of modern atmospheric contamination, resulting in underestimation of groundwater ages that cluster around 30–40 kyr. We extract CO 2 gas from groundwater using a device originally developed for studies of noble gas radionuclides. Carbon is collected in the gas phase, eliminating the possibility of fostering microbial activities and aqueous chemical reactions during sample storage. Thismore » method collects CO 2- 14C and radiokrypton ( 81Kr and 85Kr) samples simultaneously. The presence of any shorter-lived 85Kr is used to evaluate the degree of atmospheric contamination during sampling or mixing of young groundwater. Most groundwater samples showed lower CO 2- 14C activities than those of DIC- 14C, presumably due to the absence of atmospheric contamination. Samples with 81Kr age exceeding 150 kyr have no detectable CO 2- 14C except where mixing sources of young groundwater is suspected. Furthermore these field data serve as confirmations for the reliability of the newly presented sample collection and CO 2- 14C method, and for the outstanding roles of radiokrypton isotopes in characterizing old groundwater.« less

Field Degassing as a New Sampling Method for 14C Analyses in Old Groundwater

DOE PAGES

Yokochi, Reika; Bernier, Ryan; Purtschert, Roland; ...

2017-09-07

Radiocarbon ( 14C) activity in groundwater can be used to determine subsurface residence time up to ~40 kyr, providing crucial information on dynamic properties of groundwater and on paleoclimate. However, commonly applied sampling methods for dissolved inorganic carbon (DIC- 14C) are prone to low level of modern atmospheric contamination, resulting in underestimation of groundwater ages that cluster around 30–40 kyr. We extract CO 2 gas from groundwater using a device originally developed for studies of noble gas radionuclides. Carbon is collected in the gas phase, eliminating the possibility of fostering microbial activities and aqueous chemical reactions during sample storage. Thismore » method collects CO 2- 14C and radiokrypton ( 81Kr and 85Kr) samples simultaneously. The presence of any shorter-lived 85Kr is used to evaluate the degree of atmospheric contamination during sampling or mixing of young groundwater. Most groundwater samples showed lower CO 2- 14C activities than those of DIC- 14C, presumably due to the absence of atmospheric contamination. Samples with 81Kr age exceeding 150 kyr have no detectable CO 2- 14C except where mixing sources of young groundwater is suspected. Furthermore these field data serve as confirmations for the reliability of the newly presented sample collection and CO 2- 14C method, and for the outstanding roles of radiokrypton isotopes in characterizing old groundwater.« less

Bedrock, Borehole, and Water-Quality Characterization of a Methane-Producing Water Well in Wolfeboro, New Hampshire

USGS Publications Warehouse

Degnan, James R.; Walsh, Gregory J.; Flanagan, Sarah M.; Burruss, Robert A.

2008-01-01

In August 2004, a commercial drill rig was destroyed by ignition of an explosive gas released during the drilling of a domestic well in granitic bedrock in Tyngsborough, MA. This accident prompted the Massachusetts Department of Environmental Protection (MassDEP) to sample the well water for dissolved methane - a possible explosive fuel. Water samples collected from the Tyngsborough domestic well in 2004 by the MassDEP contained low levels of methane gas (Pierce and others, 2007). When the U.S. Geological Survey (USGS) sampled this well in 2006, there was no measurable amount of methane remaining in the well water (Pierce and others, 2007). Other deep water wells in nearby south-central New Hampshire have been determined to have high concentrations of naturally occurring methane (David Wunsch, New Hampshire State Geologist, 2004, written commun.). Studying additional wells in New England crystalline bedrock aquifers that produce methane may help to understand the origin of methane in crystalline bedrock. Domestic well NH-WRW-37 was chosen for this study because it is a relatively deep well completed in crystalline bedrock, it is not affected by known anthropogenic sources of methane, and it had the highest known natural methane concentration (15.5 mg/L, U.S. Geological Survey, 2007) measured in a study described by Robinson and others (2004). This well has been in use since it was drilled in 1997, and it was originally selected for study in 2000 as part of a 30 well network, major-aquifer study by the USGS' New England Coastal Basins (NECB) study unit of the National Water-Quality Assessment (NAWQA) Program. Dissolved methane in drinking water is not considered an ingestion health hazard, although the occurrence in ground water is a concern because, as a gas, its buildup in confined spaces can cause asphyxiation, fire, or explosion hazards (Mathes and White, 2006). Methane occurrence in the fractured crystalline bedrock is not widely reported or well understood. Borehole-geophysical surveys, bedrock outcrop observations, and water-quality analyses were used to define the geologic and hydrologic characteristics of NH-WRW-37. Collection of additional information on the hydraulic and geologic characteristics of the fractured bedrock and on water quality was initiated in an attempt to understand the setting where methane gas occurs in the bedrock ground water. The origin of dissolved methane in this and other wells in New Hampshire is the subject of ongoing investigations by the State of New Hampshire, the New Hampshire Geological Survey and the USGS.

Comparative assessment of nitrogen fixation methodologies, conducted in the oligotrophic North Pacific Ocean.

PubMed

Wilson, Samuel T; Böttjer, Daniela; Church, Matthew J; Karl, David M

2012-09-01

Resolution of the nitrogen (N) cycle in the marine environment requires an accurate assessment of dinitrogen (N(2)) fixation. We present here an update on progress in conducting field measurements of acetylene reduction (AR) and (15)N(2) tracer assimilation in the oligotrophic North Pacific Subtropical Gyre (NPSG). The AR assay was conducted on discrete seawater samples using a headspace analysis system, followed by quantification of ethylene (C(2)H(4)) with a reducing compound photodetector. The rates of C(2)H(4) production were measurable for nonconcentrated seawater samples after an incubation period of 3 to 4 h. The (15)N(2) tracer measurements compared the addition of (15)N(2) as a gas bubble and dissolved as (15)N(2) enriched seawater. On all sampling occasions and at all depths, a 2- to 6-fold increase in the rate of (15)N(2) assimilation was measured when (15)N(2)-enriched seawater was added to the seawater sample compared to the addition of (15)N(2) as a gas bubble. In addition, we show that the (15)N(2)-enriched seawater can be prepared prior to its use with no detectable loss (<1.7%) of dissolved (15)N(2) during 4 weeks of storage, facilitating its use in the field. The ratio of C(2)H(4) production to (15)N(2) assimilation varied from 7 to 27 when measured simultaneously in surface seawater samples. Collectively, the modifications to the AR assay and the (15)N(2) assimilation technique present opportunities for more accurate and high frequency measurements (e.g., diel scale) of N(2) fixation, providing further insight into the contribution of different groups of diazotrophs to the input of N in the global oceans.

Cryogenic Collection of Complete Subsurface Samples for Molecular Biological Analysis

DTIC Science & Technology

2012-05-01

Nitrate was analyzed by ion chromatography ( Dionex IC25) and had a detection limit of 0.01 mg/L. Fluorescein was measured using a flow-through...dissolved oxygen (DO) with a flow through electrode, Nitrate by ion chromatography , and fluorescein with a flow through fluorometer. 1.9 LARGE...measured by headspace gas chromatography (HP 7694 Headspace Sampler attached to an HP 5890 GC with an FID detector). The GC method had a detection

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

Cooper, Clay A.; Thomas, James M.; Lyles, Brad F.

Samples from a well drilled in the Astor Pass area six-km north of the Needle Rocks area of Pyramid Lake indicate that the reservoir fluid is dominantly sodium, chloride, and sulfate, with a pH between 8.6 and 8.9. The total dissolved solids in the reservoir is approximately 1600 mg/l, about half that of the TDS of the fluids in the Needle Rocks area. One sample of dissolved gas from fluids produced during a well test in the reservoir had 4He value of 2.32 x 10 14 atoms 4He/g water, or approximately 100 times the value of atmospheric 4He. This measurement,more » in conjunction with a R/Ra measurement of 0.28, suggests that most of the reservoir helium is derived from the crust, with possibly a small value (~3.3 percent) derived from the mantle. Tritium concentration of the sample was 0.09 TU, indicating that the reservoir fluid was recharged more than 60 years ago; a simple model based upon carbon-14 suggests recharge has occurred within the past 1500 years.« less

Water-quality characteristics, including sodium-adsorption ratios, for four sites in the Powder River drainage basin, Wyoming and Montana, water years 2001-2004

USGS Publications Warehouse

Clark, Melanie L.; Mason, Jon P.

2006-01-01

The U.S. Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, monitors streams throughout the Powder River structural basin in Wyoming and parts of Montana for potential effects of coalbed natural gas development. Specific conductance and sodium-adsorption ratios may be larger in coalbed waters than in stream waters that may receive the discharge waters. Therefore, continuous water-quality instruments for specific conductance were installed and discrete water-quality samples were collected to characterize water quality during water years 2001-2004 at four sites in the Powder River drainage basin: Powder River at Sussex, Wyoming; Crazy Woman Creek near Arvada, Wyoming; Clear Creek near Arvada, Wyoming; and Powder River at Moorhead, Montana. During water years 2001-2004, the median specific conductance of 2,270 microsiemens per centimeter at 25 degrees Celsius (?S/cm) in discrete samples from the Powder River at Sussex, Wyoming, was larger than the median specific conductance of 1,930 ?S/cm in discrete samples collected downstream from the Powder River at Moorhead, Montana. The median specific conductance was smallest in discrete samples from Clear Creek (1,180 ?S/cm), which has a dilution effect on the specific conductance for the Powder River at Moorhead, Montana. The daily mean specific conductance from continuous water-quality instruments during the irrigation season showed the same spatial pattern as specific conductance values for the discrete samples. Dissolved sodium, sodium-adsorption ratios, and dissolved solids generally showed the same spatial pattern as specific conductance. The largest median sodium concentration (274 milligrams per liter) and the largest range of sodium-adsorption ratios (3.7 to 21) were measured in discrete samples from the Powder River at Sussex, Wyoming. Median concentrations of sodium and sodium-adsorption ratios were substantially smaller in Crazy Woman Creek and Clear Creek, which tend to decrease sodium concentrations and sodium-adsorption ratios at the Powder River at Moorhead, Montana. Dissolved-solids concentrations in discrete samples were closely correlated with specific conductance values; Pearson's correlation coefficients were 0.98 or greater for all four sites. Regression equations for discrete values of specific conductance and sodium-adsorption ratios were statistically significant (p-values <0.001) at all four sites. The strongest relation (R2=0.92) was at the Powder River at Sussex, Wyoming. Relations on Crazy Woman Creek (R2=0.91) and Clear Creek (R2=0.83) also were strong. The relation between specific conductance and sodium-adsorption ratios was weakest (R2=0.65) at the Powder River at Moorhead, Montana; however, the relation was still significant. These data indicate that values of specific conductance are useful for estimating sodium-adsorption ratios. A regression model called LOADEST was used to estimate dissolved-solids loads for the four sites. The average daily mean dissolved-solids loads varied among the sites during water year 2004. The largest average daily mean dissolved-solids load was calculated for the Powder River at Moorhead, Montana. Although the smallest concentrations of dissolved solids were in samples from Clear Creek, the smallest average daily mean dissolved-solids load was calculated for Crazy Woman Creek. The largest loads occurred during spring runoff, and the smallest loads occurred in late summer, when streamflows typically were smallest. Dissolved-solids loads may be smaller than average during water years 2001-2004 because of smaller than average streamflow as a result of drought conditions.

FACTORS INFLUENCING PHOTOREACTIONS OF DISSOLVED ORGANIC MATTER IN A COASTAL RIVER OF THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

Photoreactions of dissolved organic matter can affect the oxidizing capacity, nutrient dynamics, trace gas exchange, and color of surface waters. This study focuses on factors that affect the photoreactions of the colored dissolved organic matter (CDOM) in the Satilla River, a co...

Multivariate relationships between groundwater chemistry and toxicity in an urban aquifer.

PubMed

Dewhurst, Rachel E; Wells, N Claire; Crane, Mark; Callaghan, Amanda; Connon, Richard; Mather, John D

2003-11-01

Multivariate statistical methods were used to investigate the causes of toxicity and controls on groundwater chemistry from 274 boreholes in an urban area (London) of the United Kingdom. The groundwater was alkaline to neutral, and chemistry was dominated by calcium, sodium, and sulfate. Contaminants included fuels, solvents, and organic compounds derived from landfill material. The presence of organic material in the aquifer caused decreases in dissolved oxygen, sulfate and nitrate concentrations, and increases in ferrous iron and ammoniacal nitrogen concentrations. Pearson correlations between toxicity results and the concentration of individual analytes indicated that concentrations of ammoniacal nitrogen, dissolved oxygen, ferrous iron, and hydrocarbons were important where present. However, principal component and regression analysis suggested no significant correlation between toxicity and chemistry over the whole area. Multidimensional scaling was used to investigate differences in sites caused by historical use, landfill gas status, or position within the sample area. Significant differences were observed between sites with different historical land use and those with different gas status. Examination of the principal component matrix revealed that these differences are related to changes in the importance of reduced chemical species.

Ice Harbor Spillway Dissolved Gas Field Studies: Before and After Spillway Deflectors

DTIC Science & Technology

2016-07-01

Executive Summary The operation of spillways on the Columbia and Snake Rivers causes the absorption of atmospheric gases (chiefly nitrogen and oxygen) to...chiefly nitrogen and oxygen) to super- saturated levels. For many operations, the total dissolved gas (TDG) levels exceed state and National...powerhouse releases. However, these mass- balance calculations conclusively show that a substantial portion of the powerhouse discharge becomes entrained

Investigating ebullition in a sand column using dissolved gas analysis and reactive transport modeling

USGS Publications Warehouse

Amos, Richard T.; Mayer, K. Ulrich

2006-01-01

Ebullition of gas bubbles through saturated sediments can enhance the migration of gases through the subsurface, affect the rate of biogeochemical processes, and potentially enhance the emission of important greenhouse gases to the atmosphere. To better understand the parameters controlling ebullition, methanogenic conditions were produced in a column experiment and ebullition through the column was monitored and quantified through dissolved gas analysis and reactive transport modeling. Dissolved gas analysis showed rapid transport of CH4 vertically through the column at rates several times faster than the bromide tracer and the more soluble gas CO2, indicating that ebullition was the main transport mechanism for CH4. An empirically derived formulation describing ebullition was integrated into the reactive transport code MIN3P allowing this process to be investigated on the REV scale in a complex geochemical framework. The simulations provided insights into the parameters controlling ebullition and show that, over the duration of the experiment, 36% of the CH4 and 19% of the CO2 produced were transported to the top of the column through ebullition.

Methane Occurrence in a Drinking Water Aquifer Before and During Natural Gas Production from the Marcellus Shale

NASA Astrophysics Data System (ADS)

Saiers, J. E.; Barth-Naftilan, E.

2017-12-01

More than 4,000 thousand wells have punctured aquifers of Pennsylvania's northern tier to siphon natural gas from the underlying Marcellus Shale. As drilling and hydraulic fracturing ramped up a decade ago, homeowner reports of well water contamination by methane and other contaminants began to emerge. Although made infrequently compared to the number of gas wells drilled, these reports were troubling and motivated our two-year, prospective study of groundwater quality within the Marcellus Shale Play. We installed multi-level sampling wells within a bedrock aquifer of a 25 km2 area that was targeted for shale gas development. These wells were sampled on a monthly basis before, during, and after seven shale gas wells were drilled, hydraulically fractured, and placed into production. The groundwater samples, together with surface water samples collected from nearby streams, were analyzed for hydrocarbons, trace metals, major ions, and the isotopic compositions of methane, ethane, water, strontium, and dissolved inorganic carbon. With regard to methane in particular, concentrations ranged from under 0.1 to over 60 mg/L, generally increased with aquifer depth, and, at some sites, exhibited considerable temporal variability. The isotopic composition of methane and hydrocarbon ratios also spanned a large range, suggesting that methane origins are diverse and, notably, shift on the time scale of this study. We will present inferences on factors governing methane occurrence across our study area by interpreting time-series data on methane concentrations and isotopic composition in context of local hydrologic variation, companion measurements of groundwater chemistry, and the known timing of key stages of natural gas extraction.

On-line fast response device and method for measuring dissolved gas in a fluid

DOEpatents

Tutu, Narinder Kumar [Manorville, NY

2011-01-11

A method and device for the measurement of dissolved gas within a fluid. The fluid, substantially a liquid, is pumped into a pipe. The flow of the fluid is temporally restricted, creating one or more low pressure regions. A measurement indicative of trapped air is taken before and after the restriction. The amount of dissolved air is calculated from the difference between the first and second measurements. Preferably measurements indicative of trapped air is obtained from one or more pressure transducers, capacitance transducers, or combinations thereof. In the alternative, other methods such as those utilizing x-rays or gamma rays may also be used to detect trapped air. Preferably, the fluid is a hydraulic fluid, whereby dissolved air in the fluid is detected.

Fate of linear alkylbenzene sulfonate in the Mississippi River

USGS Publications Warehouse

Tabor, C.F.; Barber, L.B.

1996-01-01

The 2 800-km reach of the Mississippi River between Minneapolis, MN, and New Orleans, LA, was examined for the occurrence and fate of linear alkylbenzene sulfonate (LAS), a common anionic surfactant found in municipal sewage effluents. River water and bottom sediment were sampled in the summer and fall of 1991 and in the spring of 1992. LAS was analyzed using solid- phase extraction/derivatization/gas chromatography/mass spectrometry. LAS was present on all bottom sediments at concentrations ranging from 0.01 to 20 mg/kg and was identified in 21% of the water samples at concentrations ranging from 0.1 to 28.2 ??g/L. The results indicate that LAS is a ubiquitous contaminant on Mississippi River bottom sediments and that dissolved LAS is present mainly downstream from the sewage outfalls of major cities. The removal of the higher LAS homologs and external isomers indicates that sorption and biodegradation are the principal processes affecting dissolved LAS. Sorbed LAS appears to degrade slowly.

Diffusion Study on Dissolved Hydrogen toward Effective Bioremediation of Chlorinated Ethenes in Aquitards

NASA Astrophysics Data System (ADS)

Yoshikawa, M.; Zhang, M.; Takeuchi, M.; Komai, T.

2010-12-01

In Japan, the demand for in-situ remediation of contaminated sediments is expected to increase in the future due to the recent amendment of Soil Contamination Countermeasures Act. The Japanese law requires remediating not only contaminated groundwater but also contaminated sediments including those in aquitards. In-situ remediation of contaminated aquitards has been a challenging issue and bioremediation is considered to be one of the effective techniques. In microbial degradation of chrolinated ethenes such as tetrachloroethene and trichloroethene under anaerobic environments, dissolved hydrogen plays an important role. The dechlorinating microbes utilize hydrogen and chlorinated ethenes as an electron donor and an electron accepter, respectively. The size of hydrogen molecule is extremely small and the diffusion rate of dissolved hydrogen in an aquitard would be the key factor that controls the process of microbial dechlorination. However, the diffusion behavior of dissolved hydrogen in subsurface sediments remains unclear. The purposes of this study are to develop a practically utilizable test apparatus, carry out a series of dissolved hydrogen diffusion tests on representative samples, and illustrate the applicability of bioremediation in aquitards. A completely leak-free apparatus was developed by using aluminum alloy and gas tight rubber. This apparatus is capable of testing specimens with a diameter as large as 100 mm by a length from 5 mm to 10 mm, depending on the maximum grain size within a test specimen. Preliminary tests have been performed with glass beads as an ideal material, commercially available kaolin clay, and core samples taken from a polluted site containing clay minerals. The effective diffusion coefficients of these samples were all on the order of 10E-10 m2/s, though their coefficients of permeability varied between the orders of 10E-2 and 10E-7 cm/s. These results showed that there was no obvious relationship between the effective diffusion coefficient of hydrogen and coefficient of permeability. This observation indicates that dissolved hydrogen also diffuses through hydraulically-tight soil particles and bioremediation of chlorinated ethenes in aquitards would be possible from the aspect of electron donor supply.

Gas buildup in Lake Nyos, Cameroon: The recharge process and its consequences

USGS Publications Warehouse

Evans, William C.; Kling, G.W.; Tuttle, M.L.; Tanyileke, G.; White, L.D.

1993-01-01

The gases dissolved in Lake Nyos, Cameroon, were quantified recently (December 1989 and September 1990) by two independent techniques: in-situ measurements using a newly designed probe and laboratory analyses of samples collected in pre-evacuated stainless steel cylinders. The highest concentrations of CO2 and CH4 were 0.30 mol/kg and 1.7 mmol/kg, respectively, measured in cylinders collected 1 m above lake bottom. Probe measurements of in-situ gas pressure at three different stations showed that horizontal variations in total dissolved gas were negligible. Total dissolved-gas pressure near the lake bottom is 1.06 MPa (10.5 atm), 50% as high as the hydrostatic pressure of 2.1 MPa (21 atm). Comparing the CO2 profile constructed from the 1990 data to one obtained in May 1987 shows that CO2 concentrations have increased at depths to below 150 m. Based on these profiles, the average rate of CO2 input to bottom waters was 2.6 ?? 108 mol/a. Increased deep-water temperatures require an average heat flow of 0.32 MW into the hypolimnion over the same time period. The transport rates of CO2, heat, and major ions into the hypolimnion suggest that a low-temperature reservoir of free CO2 exists a short distance below lake bottom and that convective cycling of lake water through the sediments is involved in transporting the CO2 into the lake from the underlying diatreme. Increased CH4 concentrations at all depths below the oxycline and a high 14C content (41% modern) in the CH4 4 m above lake bottom show that much of the CH4 is biologically produced within the lake. The CH4 production rate may vary with time, but if the CO2 recharge rate remains constant, CO2 saturation of the entire hypolimnion below 50 m depth would require ???140 a, given present-day concentrations. ?? 1993.

Chemical and stable isotopic evidence for water/rock interaction and biogenic origin of coalbed methane, Fort Union Formation, Powder River Basin, Wyoming and Montana U.S.A

USGS Publications Warehouse

Rice, C.A.; Flores, R.M.; Stricker, G.D.; Ellis, M.S.

2008-01-01

Significant amounts (> 36??million m3/day) of coalbed methane (CBM) are currently being extracted from coal beds in the Paleocene Fort Union Formation of the Powder River Basin of Wyoming and Montana. Information on processes that generate methane in these coalbed reservoirs is important for developing methods that will stimulate additional production. The chemical and isotopic compositions of gas and ground water from CBM wells throughout the basin reflect generation processes as well as those that affect water/rock interaction. Our study included analyses of water samples collected from 228 CBM wells. Major cations and anions were measured for all samples, ??DH2O and ??18OH2O were measured for 199 of the samples, and ??DCH4 of gas co-produced with water was measured for 100 of the samples. Results show that (1) water from Fort Union Formation coal beds is exclusively Na-HCO3-type water with low dissolved SO4 content (median < 1??mg/L) and little or no dissolved oxygen (< 0.15??mg/L), whereas shallow groundwater (depth generally < 120??m) is a mixed Ca-Mg-Na-SO4-HCO3 type; (2) water/rock interactions, such as cation exchange on clay minerals and precipitation/dissolution of CaCO3 and SO4 minerals, account for the accumulation of dissolved Na and depletion of Ca and Mg; (3) bacterially-mediated oxidation-reduction reactions account for high HCO3 (270-3310??mg/L) and low SO4 (median < 0.15??mg/L) values; (4) fractionation between ??DCH4 (- 283 to - 328 per mil) and ??DH2O (- 121 to - 167 per mil) indicates that the production of methane is primarily by biogenic CO2 reduction; and (5) values of ??DH2O and ??18OH2O (- 16 to - 22 per mil) have a wide range of values and plot near or above the global meteoric water line, indicating that the original meteoric water has been influenced by methanogenesis and by being mixed with surface and shallow groundwater.

Malignant human cell transformation of Marcellus shale gas drilling flow back water

PubMed Central

Yao, Yixin; Chen, Tingting; Shen, Steven S.; Niu, Yingmei; DesMarais, Thomas L; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max

2015-01-01

The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation is known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these waste waters, flow back water from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy / energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC50 values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependant. In addition, flow back water-transformed BEAS-2B cells show a better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. PMID:26210350

Methanethiol Concentrations and Sea-Air Fluxes in the Subarctic NE Pacific Ocean

NASA Astrophysics Data System (ADS)

Kiene, R. P.; Williams, T. E.; Esson, K.; Tortell, P. D.; Dacey, J. W. H.

2017-12-01

Exchange of volatile organic sulfur from the ocean to the atmosphere impacts the global sulfur cycle and the climate system and is thought to occur mainly via the gas dimethylsulfide (DMS). DMS is produced during degradation of the abundant phytoplankton osmolyte dimethylsulfoniopropionate (DMSP) but bacteria can also convert dissolved DMSP into the sulfur gas methanethiol (MeSH). MeSH has been difficult to measure in seawater because of its high chemical and biological reactivity and, thus, information on MeSH concentrations, distribution and sea-air fluxes is limited. We measured MeSH in the northeast subarctic Pacific Ocean in July 2016, along transects with strong phytoplankton abundance gradients. Water samples obtained with Niskin bottles were analyzed for MeSH by purge-and-trap gas chromatography. Depth profiles showed that MeSH concentrations were high near the surface and declined with depth. Surface waters (5 m depth) had an average MeSH concentration of 0.75 nM with concentrations reaching up to 3nM. MeSH concentrations were correlated (r = 0.47) with microbial turnover of dissolved DMSP which ranged up to 236 nM per day. MeSH was also correlated with total DMSP (r = 0.93) and dissolved DMS (r = 0.63), supporting the conclusion that DMSP was a major precursor of MeSH. Surface water MeSH:DMS concentration ratios averaged 0.19 and ranged up to 0.50 indicating that MeSH was a significant fraction of the volatile sulfur pool in surface waters. Sea-air fluxes of MeSH averaged 15% of the combined DMS+MeSH flux, therefore MeSH contributed an important fraction of the sulfur emitted to the atmosphere from the subarctic NE Pacific Ocean.

Dissolved Greenhouse Gas Concentration Patterns and Relationships with Stream Chemistry in Tropical Headwater Streams

NASA Astrophysics Data System (ADS)

López-Lloreda, C.; McDowell, W. H.; Potter, J.

2017-12-01

Recent studies have shown that freshwater ecosystems, mainly lakes and large rivers, can be an important source of greenhouse gas (GHG) emissions. Headwater streams have received less attention but have been identified as being a potentially important contributor to these emissions. The complex biogeochemical interactions between dissolved GHG, stream chemistry and other physicochemical parameters in streams are not well understood, particularly in small, tropical headwater streams. Surface water samples were taken at weekly intervals at 8 sites in the Luquillo Experimental Forest in Puerto Rico. Samples were analyzed for carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) as well as dissolved organic carbon (DOC), nitrate (NO3) and other major cations and anions. Additionally, physicochemical parameters and discharge (at a subset of sites) were recorded for each sample. Initial analyses of stream greenhouse gas concentrations showed very little seasonality across all sites as well as no change in concentrations during a drought in 2015. One of our hypothesized drivers, discharge, did not show any significant relationship with any of the greenhouse gases at our two gaged sites. Relationships between GHG and stream chemistry, mainly DOC and NO3, varied across sites. A significant negative relationship was found between NO3 and N2O when data were pooled across all sites, but no significant relationship was found at any individual site. CH4 was positively correlated with NO3, but only at one of our sites. N2O showed a significant positive relationship with DOC at two of our sites but interestingly, CO2 and CH4 did not show any significant relationship with DOC. Our initial results suggest that NO3 can be an important driver for N2O and CH4 concentrations, while DOC can be an important driver for N2O. Our results differ from those found in lowland tropical rivers, suggesting that river order and floodplain connections may be important drivers of GHG biogeochemistry. We have also observed a decoupling between DOC and CO2, similar to that which has been observed in previous long-term research in other biomes. The role of tropical montane streams in GHG evasion thus needs to be assessed directly, and cannot be inferred from work on larger tropical rivers.

CO2-filled vesicles in mid-ocean basalt

USGS Publications Warehouse

Moore, J.G.; Batchelder, J.N.; Cunningham, C.G.

1977-01-01

Volatile-filled vesicles are present in minor amounts in all samples of mid-ocean basalt yet collected (and presumably erupted) down to depths of 4.8 km. When such vesicles are pierced in liquid under standard conditions, the volume expansion of the gas is 0.2 ?? 0.05 times the eruption pressure in bars or 20 ?? 5 times the eruption depth in km. Such expansion could be used as a measure of eruption depth. A variety of techniques: (1) vacuum crushing and gas chromatographic, freezing separation, and mass spectrographic analyses; (2) measurements of phase changes on a freezing microscope stage; (3) microscopic chemical and solubility observations; and (4) volume change measurements, all indicate that CO2 comprises more than 95% by volume of the vesicle gas in several submarine basalt samples from the Atlantic and Pacific. The CO2 held in vesicles is present in quantities about equal to or greater than that presumed to be dissolved in the glass (melt) and amounts to 400-900 ppm of the rock. The rigid temperature of the glass is 800-1000??C and increases for shallower samples. A sulfur gas was originally present in subordinate amounts in the vesicles, but has largely reacted with iron in the vesicle walls to produce sulfide spherules. ?? 1977.

Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans

USGS Publications Warehouse

Pohlman, J.W.; Bauer, J.E.; Waite, W.F.; Osburn, C.L.; Chapman, N.R.

2011-01-01

Marine sediments contain about 500-10,000 Gt of methane carbon, primarily in gas hydrate. This reservoir is comparable in size to the amount of organic carbon in land biota, terrestrial soils, the atmosphere and sea water combined, but it releases relatively little methane to the ocean and atmosphere. Sedimentary microbes convert most of the dissolved methane to carbon dioxide. Here we show that a significant additional product associated with microbial methane consumption is methane-derived dissolved organic carbon. We use ??14 C and ??13 C measurements and isotopic mass-balance calculations to evaluate the contribution of methane-derived carbon to seawater dissolved organic carbon overlying gas hydrate-bearing seeps in the northeastern Pacific Ocean. We show that carbon derived from fossil methane accounts for up to 28% of the dissolved organic carbon. This methane-derived material is much older, and more depleted in 13 C, than background dissolved organic carbon. We suggest that fossil methane-derived carbon may contribute significantly to the estimated 4,000-6,000 year age of dissolved organic carbon in the deep ocean, and provide reduced organic matter and energy to deep-ocean microbial communities. ?? 2011 Macmillan Publishers Limited. All rights reserved.

Hydrogeology and water quality in the Snake River alluvial aquifer at Jackson Hole Airport, Jackson, Wyoming, water years 2011 and 2012

USGS Publications Warehouse

Wright, Peter R.

2013-01-01

The hydrogeology and water quality of the Snake River alluvial aquifer at the Jackson Hole Airport in northwest Wyoming was studied by the U.S. Geological Survey, in cooperation with the Jackson Hole Airport Board, during water years 2011 and 2012 as part of a followup to a previous baseline study during September 2008 through June 2009. Hydrogeologic conditions were characterized using data collected from 19 Jackson Hole Airport wells. Groundwater levels are summarized in this report and the direction of groundwater flow, hydraulic gradients, and estimated groundwater velocity rates in the Snake River alluvial aquifer underlying the study area are presented. Analytical results of groundwater samples collected from 10 wells during water years 2011 and 2012 are presented and summarized. The water table at Jackson Hole Airport was lowest in early spring and reached its peak in July or August, with an increase of 12.5 to 15.5 feet between April and July 2011. Groundwater flow was predominantly horizontal but generally had the hydraulic potential for downward flow. Groundwater flow within the Snake River alluvial aquifer at the airport was from the northeast to the west-southwest, with horizontal velocities estimated to be about 25 to 68 feet per day. This range of velocities slightly is broader than the range determined in the previous study and likely is due to variability in the local climate. The travel time from the farthest upgradient well to the farthest downgradient well was approximately 52 to 142 days. This estimate only describes the average movement of groundwater, and some solutes may move at a different rate than groundwater through the aquifer. The quality of the water in the alluvial aquifer generally was considered good. Water from the alluvial aquifer was fresh, hard to very hard, and dominated by calcium carbonate. No constituents were detected at concentrations exceeding U.S. Environmental Protection Agency maximum contaminant levels or health advisories; however, reduction and oxidation (redox) measurements indicate oxygen-poor water in many of the wells. Gasoline-range organics, three volatile organic compounds, and triazoles were detected in some groundwater samples. The quality of groundwater in the alluvial aquifer generally was suitable for domestic and other uses; however, dissolved iron and manganese were detected in samples from many of the monitor wells at concentrations exceeding U.S. Environmental Protection Agency secondary maximum contaminant levels. Iron and manganese likely are both natural components of the geologic materials in the area and may have become mobilized in the aquifer because of redox processes. Additionally, measurements of dissolved-oxygen concentrations and analyses of major ions and nutrients indicate reducing conditions exist at 7 of the 10 wells sampled. Measurements of dissolved-oxygen concentrations (less than 0.1 to 9 milligrams per liter) indicated some variability in the oxygen content of the aquifer. Dissolved-oxygen concentrations in samples from 3 of the 10 wells indicated oxic conditions in the aquifer, whereas low dissolved-oxygen concentrations (less than 1 milligram per liter) in samples from 7 wells indicated anoxic conditions. Nutrients were present in low concentrations in all samples collected. Nitrate plus nitrite was detected in samples from 6 of the 10 monitored wells, whereas dissolved ammonia was detected in small concentrations in 8 of the 10 monitored wells. Dissolved organic carbon concentrations generally were low. At least one dissolved organic carbon concentration was quantified by the laboratory in samples from all 10 wells; one of the concentrations was an order of magnitude higher than other detected dissolved organic carbon concentrations, and slightly exceeded the estimated range for natural groundwater. Samples were collected for analyses of dissolved gases, and field analyses of ferrous iron, hydrogen sulfide, and low-level dissolved oxygen were completed to better understand the redox conditions of the alluvial aquifer. Dissolved gas analyses confirmed low concentrations of dissolved oxygen in samples from wells where reducing conditions exist and indicated the presence of methane gas in samples from several wells. Redox processes in the alluvial aquifer were identified using a model designed to use a multiple-lines-of-evidence approach to distinguish reduction processes. Results of redox analyses indicate iron reduction was the dominant redox process; however, the model indicated manganese reduction and methanogenesis also were taking place in the aquifer. Each set of samples collected during this study included analysis of at least two, but often many anthropogenic compounds. During the previous 2008–09 study at Jackson Hole Airport, diesel-range organics were measured in small (estimated) concentrations in several samples. Samples collected from all 10 wells sampled during the 2011–12 study were analyzed for diesel-range organics, and there were no detections; however, several other anthropogenic compounds were detected in groundwater samples during water years 2011—12 that were not detected during the previous 2008–09 study. Gasoline-range organics, benzene, ethylbenzene, and total xylene were each detected (but reported as estimated concentrations) in at least one groundwater sample. These compounds were not detected during the previous study or consistently during this study. Several possible reasons these compounds were not detected consistently include (1) these compounds are present in the aquifer at concentrations near the analytical method detection limit and are difficult to detect, (2) these compounds were not from a persistent source during this study, and (3) these compounds were detected because of contamination introduced during sampling or analysis. During water years 2011–2012, groundwater samples were analyzed for triazoles, specifically benzotriazole, 4-methyl-1H-benzotriazole, and 5-methyl-1H-benzotriazole. Triazoles are anthropogenic compounds often used as an additive in deicing and anti-icing fluids as a corrosion inhibitor, and can be detected at lower laboratory reporting levels than glycols, which previously had not been detected. Two of the three triazoles measured, 4-methyl-1H-benzotriazole and 5-methyl-1H-benzotriazole, were detected at low concentrations in groundwater at 7 of the 10 wells sampled. The detection of triazole compounds in groundwater downgradient from airport operations makes it unlikely there is a natural cause for the high rates of reduction present in many airport monitor wells. It is more likely that aircraft deicers, anti-icers, or pavement deicers have seeped into the groundwater system and caused the reducing conditions.

Method 366.0 Determination of Dissolved Silicate in Estuarine and Coastal Watersby Gas Segmented Continuous Flow Colorimetric Analysis

EPA Science Inventory

This method provides a procedure for the determination of dissolved silicate concentration in estuarine and coastal waters. The dissolved silicate is mainly in the form of silicic acid, H SiO , in estuarine and 4 4 coastal waters. All soluble silicate, including colloidal silici...

UNDERSTANDING AND MANAGING RISKS POSED BY BRINES CONTAINING DISSOLVED CARBON DIOXIDE

EPA Science Inventory

Geologic disposal of supercritical carbon dioxide in saline aquifers and depleted oil and gas fields will cause large volumes of brine to become saturated with dissolved CO₂ at concentrations of 50 g/l or more.  As CO₂ dissolves in brine, the brine de...

Bubble growth as a means to measure dissolved nitrogen concentration in aerated water

NASA Astrophysics Data System (ADS)

Ando, Keita; Yamashita, Tatsuya

2017-11-01

Controlling the amount of dissolved gases in water is important, for example, to food processing; it is essential to quantitatively evaluate dissolved gas concentration. The concentration of dissolved oxygen (DO) can be measured by commercial DO meters, but that of dissolved nitrogen (DN) cannot be obtained easily. Here, we propose a means to measure DN concentration based on Epstein-Plesset-type analysis of bubble growth under dissolved gas supersaturation. DO supersaturation in water is produced by oxygen microbubble aeration. The diffusion-driven growth of bubbles nucleated at glass surfaces in contact with the aerated water is first observed. The observed growth is then compared to the extended Epstein-Plesset theory that considers Fick's mass transfer of both DO and DN across bubble interfaces; in this comparison, the unknown DN concentration is treated as a fitting parameter. Comparisons between the experiment and the theory suggest, as expected, that DN can be effectively purged by oxygen microbubble aeration. This study was supported in part by the Mizuho Foundation for the Promotion of Science and by a MEXT Grant-in-Aid for the Program for Leading Graduate Schools.

Raman Spectroscopic Measurements of Co2 Dissolved in Seawater for Laser Remote Sensing in Water

NASA Astrophysics Data System (ADS)

Somekawa, Toshihiro; Fujita, Masayuki

2016-06-01

We examined the applicability of Raman lidar technique as a laser remote sensing tool in water. The Raman technique has already been used successfully for measurements of CO2 gas dissolved in water and bubbles. Here, the effect of seawater on CO2 Raman spectra has been evaluated. A frequency doubled Q-switched Nd:YAG laser (532 nm) was irradiated to CO2 gas dissolved in a standard seawater. In seawater, the Raman signals at 984 and 1060-1180 cm-1 from SO42- were detected, which shows no spectral interference caused by Raman signals derived from CO2.

Air-water exchange and dry deposition of polybrominated diphenyl ethers at a coastal site in Izmir Bay, Turkey.

PubMed

Cetin, Banu; Odabasi, Mustafa

2007-02-01

The air-water exchange of polybrominated diphenyl ethers (PBDEs), an emerging class of persistent organic pollutants (POPs), was investigated using paired air-water samples (n = 15) collected in July and December, 2005 from Guzelyali Port in Izmir Bay, Turkey. Total dissolved-phase water concentrations of PBDEs (sigma7PBDEs) were 212 +/- 65 and 87 +/- 57 pg L(-1) (average +/- SD) in summer and winter, respectively. BDE-209 was the most abundant congener in all samples, followed by BDE-99 and -47. Average ambient gas-phase sigma7PBDE concentrations were between 189 +/- 61 (summer) and 76 +/- 65 pg m(-3) (winter). Net air-water exchange fluxes ranged from -0.9 +/- 1.0 (BDE-28) (volatilization) to 11.1 +/- 5.4 (BDE-209) ng m(-2) day(-1) (deposition). The BDE-28 fluxes were mainly volatilization while the other congeners were deposited. Gas- and dissolved-phase concentrations were significantly correlated (P = 0.33-0.55, p < 0.05, except for BDE-209, r = 0.05, p > 0.05) indicating thatthe atmosphere controls the surface water PBDE levels in this coastal environment. Estimated particulate dry deposition fluxes ranged between 2.7 +/- 1.9 (BDE-154) and 116 +/- 84 ng m(-2) day(-1) (BDE-209) indicating that dry deposition is also a significant input to surface waters in the study area.

Productivity Estimation of Hypersaline Microbial Mat Communities - Diurnal Cycles of Dissolved Oxygen

NASA Astrophysics Data System (ADS)

Less, G.; Cohen, Y.; Luz, B.; Lazar, B.

2002-05-01

Hypersaline microbial mat communities (MMC) are the modern equivalents of the Archean stromatolities, the first photosynthetic organisms on Earth. An estimate of their oxygen production rate is important to the understanding of oxygen evolution on Earth ca. 2 b.y.b.p. Here we use the diurnal cycle of dissolved oxygen, O2/Ar ratio and the isotopic composition of dissolved oxygen to calculate net and gross primary productivity of MMC growing in a large scale (80 m2) experimental pan. The pan is inoculated with MMC taken from the Solar Lake, Sinai, Egypt and filled with 90\\permil evaporated Red Sea water brine up to a depth of ca. 0.25 m. It is equipped with computerized flow through system that is programmed to pump pan water at selected time intervals into a sampling cell fitted with dissolved oxygen, pH, conductivity and temperature sensors connected to a datalogger. Manual brine samples were taken for calibrating the sensors, mass spectrometric analyses and for measurements of additional relevant parameters. Dissolved oxygen concentrations fluctuate during the diurnal cycle being highly supersaturated except for the end of the night. The O2 curve varies seasonally and has a typical "shark fin" shape due to the MMC metabolic response to the shape of the diurnal light curve. The dissolved oxygen data were fitted to a smooth curve that its time derivative (dO2 /dt) is defined as: Z dO2 /dt=GP-R-k(O2(meas)- O2(sat)) where z is the depth (m); GP and R are the MMC gross production and respiration (mol m-2 d-1), respectively; k is the gas exchange coefficient (m d-1); O2(meas) and O2(sat) (mol L-1) are the measured and equilibrium dissolved oxygen concentrations, respectively. The high resolution sampling of the automated system produces O2 curves that enable the calculation of smooth and reliable time derivatives. The calculations yield net production values that vary between 1,000 10-6 to -100 10-6 mol O2 m-2 h-1 and day respiration rates between 60 10-6 to 30 10-6 mol O2 m-2 h-1 in summer and winter, respectively. Independent estimate of the gross productivity and respiration is provided by the oxygen isotopic measurements.

Liquid and gas phase NMR spectra of 13CH313CHO acetaldehyde

NASA Astrophysics Data System (ADS)

Makulski, Włodzimierz; Wikieł, Agata J.

2018-01-01

The gas phase NMR experiments perform a vital role in establishing the magnetic shielding and spin-spin coupling constants which are free from intermolecular interactions, equivalent to the parameter of isolated molecules. This work is concerned with an acetaldehyde molecule. Small amounts of acetaldehyde 13CH313CHO in gaseous matrices of CO2 and Xe were studied using high-precision 1H and 13C NMR measurements. Results were extrapolated to the zero-density limit permitting the determinations of the 1H and 13C absolute nuclear magnetic shielding of an isolated acetaldehyde molecule. The difference between the experimental and recent theoretical DFT results is discussed. Several samples of 13CH313CHO dissolved in popular organic and inorganic solvents were also investigated. Gas-to-solution shifts show the influence of the association process when acetaldehyde is transferred from gas to liquid state. Several spin-spin coupling constants in the gas phase and in different solvents were precisely measured.

The interaction of molecular hydrogen with α-radiolytic oxidants on a (U,Pu)O2 surface

NASA Astrophysics Data System (ADS)

Bauhn, Lovisa; Hansson, Niklas; Ekberg, Christian; Fors, Patrik; Delville, Rémi; Spahiu, Kastriot

2018-07-01

In order to assess the impact of α-radiolysis of water on the oxidative dissolution of spent fuel, an un-irradiated, annealed MOX fuel pellet with high content of Pu (∼24 wt%), and a specific α-activity of 4.96 GBq/gMOX, was leached in carbonate-containing solutions of low ionic strength. The high Pu content in the pellet stabilizes the (U,Pu)O2(s) matrix towards oxidative dissolution, whereas the α-decays emitted from the surface are expected to produce ∼3.6 × 10-7 mol H2O2/day, contributing to the oxidative dissolution of the pellet. Two sets of leaching tests were conducted under different redox conditions: Ar gas atmosphere and deuterium gas atmosphere. A relatively slow increase of the U and Pu concentrations was observed in the Ar case, with U concentrations increasing from 1·10-6 M after 1 h to ∼7 × 10-5 M after 58 days. Leaching under an atmosphere starting at 1 MPa deuterium gas was undertaken in order to evaluate any effect of dissolved hydrogen on the radiolytic dissolution of the pellet, as well as to investigate any potential recombination of the α-radiolytic products with dissolved deuterium. For the latter purpose, isotopic analysis of the D/H content was carried out on solution samples taken during the leaching. Despite the continuous production of radiolytic oxidants, the concentrations of U and Pu remained quite constant at the level of ∼3 × 10-8 M during the first 30 days, i.e. as long as the deuterium pressure remained higher than 0.8 MPa. These data rule out any oxidative dissolution of the pellet during the first month. The un-irradiated MOX fuel does not contain metallic ε-particles, hence it is mainly the interaction of radiolytic oxidants and dissolved deuterium with the surface of the mixed actinide oxide that causes the neutralization of the oxidants. This conclusion is supported by the steadily increasing levels of HDO measured in the leachate samples.

Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

PubMed

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

Improved Arterial Blood Oxygenation Following Intravenous Infusion of Cold Supersaturated Dissolved Oxygen Solution

PubMed Central

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

BACKGROUND One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. METHODS Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer’s lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. RESULTS Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. CONCLUSIONS A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model. PMID:25249764

Determination of biomass burning tracers in air samples by GC/MS

NASA Astrophysics Data System (ADS)

Janoszka, Katarzyna

2018-01-01

Levoglucosan (LG) as a main cellulose burning product at 300°C is a biomass burning tracer. LG characterize by relatively high molar mass and it is sorbed by particulate matter. In the study of air pollution monitoring LG is mainly analyzed in particulate matter, PM1 and PM2,5. The tracer create relatively high O-H…O bond and weaker C-H…O bond. Due to the hydrogen bond, LG dissolves very well in water. Analytical procedure of LG determination include: extraction, derivatization and analysis by gas chromatography coupled with mass spectrometry detector. In water samples levoglucosan is determined by liquid chromatography. The paper presents a methodology for particulate matter samples determination their analysis by gas chromatography coupled with a mass spectrometry detector. Determination of LG content in particulate matter was performed according to an analytical method based on simultaneous pyridine extraction and derivatization using N,O-bis (trimethylsilyl) trifluoroacetamide and trimethylchlorosilane mixture (BSTFA: TMCS, 99: 1).

The dissolution or growth of a gas bubble inside a drop in zero gravity

NASA Technical Reports Server (NTRS)

Kondos, Pericles A.; Subramanian, R. Shankar; Weinberg, Michael C.

1987-01-01

The radius-time history of a gas bubble located concentrically within a spherical liquid drop in a space laboratory is analyzed within the framework of the quasi-stationary approximation. Illustrative results are calculated from the theory which demonstrate interesting qualitative features. For instance, when a pure gas bubble dissolves within a liquid drop in an environment containing the same gas and some inert species, the dissolution can be more or less rapid than that in an unbounded liquid depending on the initial relative size of the drop. Further, given a similar growth situation, indefinite growth is not possible, and the bubble will initially grow, but always dissolve in the end.

Assessing Methane in Shallow Groundwater in Unconventional Oil and Gas Play Areas, Eastern Kentucky.

PubMed

Zhu, Junfeng; Parris, Thomas M; Taylor, Charles J; Webb, Steven E; Davidson, Bart; Smath, Richard; Richardson, Stephen D; Molofsky, Lisa J; Kromann, Jenna S; Smith, Ann P

2018-05-01

The expanding use of horizontal drilling and hydraulic fracturing technology to produce oil and gas from tight rock formations has increased public concern about potential impacts on the environment, especially on shallow drinking water aquifers. In eastern Kentucky, horizontal drilling and hydraulic fracturing have been used to develop the Berea Sandstone and the Rogersville Shale. To assess baseline groundwater chemistry and evaluate methane detected in groundwater overlying the Berea and Rogersville plays, we sampled 51 water wells and analyzed the samples for concentrations of major cations and anions, metals, dissolved methane, and other light hydrocarbon gases. In addition, the stable carbon and hydrogen isotopic composition of methane (δ 13 C-CH 4 and δ 2 H-CH 4 ) was analyzed for samples with methane concentration exceeding 1 mg/L. Our study indicates that methane is a relatively common constituent in shallow groundwater in eastern Kentucky, where methane was detected in 78% of the sampled wells (40 of 51 wells) with 51% of wells (26 of 51 wells) exhibiting methane concentrations above 1 mg/L. The δ 13 C-CH 4 and δ 2 H-CH 4 ranged from -84.0‰ to -58.3‰ and from -246.5‰ to -146.0‰, respectively. Isotopic analysis indicated that dissolved methane was primarily microbial in origin formed through CO 2 reduction pathway. Results from this study provide a first assessment of methane in the shallow aquifers in the Berea and Rogersville play areas and can be used as a reference to evaluate potential impacts of future horizontal drilling and hydraulic fracturing activities on groundwater quality in the region. © 2017, National Ground Water Association.

Characterizing Gas Transport in Wetland Soil-Root Systems with Dissolved Gas Tracer Techniques

NASA Astrophysics Data System (ADS)

Reid, M. C.; Jaffe, P. R.

2016-12-01

Soil fluxes of methane (CH4), nitrous oxide (N2O), and other biogenic gases depend on coupling between microbial and physiochemical processes within soil media. The importance of plant-mediated transport in wetland CH4 emissions is well known, but a generalized understanding of gas transfer between pore water and root aerenchyma, and how this process competes with biogeochemical production/consumption of gases beyond CH4, is incomplete [1]. A lack of experimental approaches to characterize transport processes in complex soil-water-plant systems at field scale has limited efforts to close this knowledge gap. In this presentation we describe dissolved gas tracer techniques to tease apart effects of transport from simultaneous biochemical reaction on trace gas dynamics in soils. We discuss a push-pull test with helium and sulfur hexafluoride gas tracers to quantify in situ root-mediated gas transfer kinetics in a wetland soil [2]. A Damköhler number analysis is introduced to interpret the results and evaluate the balance between biochemical reaction and root-driven gas transfer in controlling the fate of CH4 and N2O in vegetated wetland soils. We conclude with a brief discussion of other problems in soil gas dynamics that can be addressed with gas tracer approaches. [1] Blagodatsky and Smith 2012. Soil physics meets soil biology: Towards better mechanistic prediction of greenhouse gas emissions from soil. Soil Biology and Biochemistry 47, 78-92. [2] Reid et al. 2015. Dissolved gas dynamics in wetland soils: Root-mediated gas transfer kinetics determind via push-pull tracer tests. Water Resour. Res. 51, doi:10.1002/2014WR016803.

Flue gas desulfurization/denitrification using metal-chelate additives

DOEpatents

Harkness, John B. L.; Doctor, Richard D.; Wingender, Ronald J.

1986-01-01

A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

Gasometer: An inexpensive device for continuous monitoring of dissolved gases and supersaturation

USGS Publications Warehouse

Bouck, G.R.

1982-01-01

The “gasometer” is a device that measures differential dissolved-gas pressures (δP) in water relative to barometric pressure (as does the “Weiss saturometer”), but operates continuously without human attention. The gasometer can be plumbed into a water-supply system and requires 8 liters/minute of water or more at 60 kilopascals. The gasometer's surfaces are nontoxic, and flow-through water can be used for fish culture. The gasometer may be connected to a small submersible pump and operated as a portable unit. The gasometer can activate an alarm system and thus protect fish from hyperbaric (supersaturation) or hypobaric gas pressures (usually due to low dissolved oxygen). Instructions are included for calculating and reporting data including the pressure and saturation of individual gases. Construction and performance standards are given for the gasometer. Occasional cleaning is required to remove biofouling from the gas-permeable tubing.PDF

The growth of oscillating bubbles in an ultrasound field

NASA Astrophysics Data System (ADS)

Yamauchi, Risa; Yamashita, Tatsuya; Ando, Keita

2017-11-01

From our recent experiments to test particle removal by underwater ultrasound, dissolved gas supersaturation is found to play an important role in physical cleaning; cavitation bubble nucleation can be triggered easily by weak ultrasound under the supersaturation and mild motion of the bubbles contributes to efficient cleaning without erosion. The state of gas bubble nuclei in water is critical to the determination of a cavitation inception threshold. Under ultrasound forcing, the size of bubble nuclei is varied by the transfer of dissolved gas (i.e., rectified diffusion); the growth rate will be promoted by the supersaturation and is thus expected to contribute to cavitation activity enhancement. In the present work, we experimentally study rectified diffusion for bubbles attached at glass surfaces in an ultrasound field. We will present the evolution of bubble nuclei sizes with varying parameters such as dissolved oxygen supersaturation, and ultrasound intensity and frequency. the Research Grant of Keio Leading-edge Laboratory of Science & Technology.

Redox chemistry in the phosphorus biogeochemical cycle

NASA Astrophysics Data System (ADS)

Pasek, Matthew A.; Sampson, Jacqueline M.; Atlas, Zachary

2014-10-01

The element phosphorus (P) controls growth in many ecosystems as the limiting nutrient, where it is broadly considered to reside as pentavalent P in phosphate minerals and organic esters. Exceptions to pentavalent P include phosphine-PH3-a trace atmospheric gas, and phosphite and hypophosphite, P anions that have been detected recently in lightning strikes, eutrophic lakes, geothermal springs, and termite hindguts. Reduced oxidation state P compounds include the phosphonates, characterized by C-P bonds, which bear up to 25% of total organic dissolved phosphorus. Reduced P compounds have been considered to be rare; however, the microbial ability to use reduced P compounds as sole P sources is ubiquitous. Here we show that between 10% and 20% of dissolved P bears a redox state of less than +5 in water samples from central Florida, on average, with some samples bearing almost as much reduced P as phosphate. If the quantity of reduced P observed in the water samples from Florida studied here is broadly characteristic of similar environments on the global scale, it accounts well for the concentration of atmospheric phosphine and provides a rationale for the ubiquity of phosphite utilization genes in nature. Phosphine is generated at a quantity consistent with thermodynamic equilibrium established by the disproportionation reaction of reduced P species. Comprising 10-20% of the total dissolved P inventory in Florida environments, reduced P compounds could hence be a critical part of the phosphorus biogeochemical cycle, and in turn may impact global carbon cycling and methanogenesis.

Selective gas-chromatographic detection using an ion-selective electrode-II Selective detection of fluorine compounds.

PubMed

Kojima, T; Ichise, M; Seo, Y

1972-04-01

Components in samples are separated on a gas chromatography column using hydrogen as carrier gas. The individual components from the column are passed through a platinum tube heated at 1000 degrees , where they undergo hydrogenolysis, and fluorine compounds are converted into hydrogen fluoride. The hydrogen fluoride is dissolved in a slow stream of an absorption solution, and the fluoride ion concentration in the resulting solution is monitored in a flow-cell with a fluoride ion electrode. The potentiometric output of the cell is converted into a signal, which is proportional to the concentration of fluoride ion, by an antilogarithmic converter, and recorded. The response of the detector to fluorine compounds was about 10,000 times that to an equal quantity of other organic compounds, and 5 x 10(-11) mole of fluorobenzene could be detected.

Excess air during aquifer storage and recovery in an arid basin (Las Vegas Valley, USA)

NASA Astrophysics Data System (ADS)

Solomon, D. Kip; Cole, Erin; Leising, Joseph F.

2011-02-01

The Las Vegas Valley Water District in Nevada, USA, has operated an artificial recharge (AR) program since 1989. In summer 2001, observations of gas exsolving from tap water prompted a study that revealed total dissolved gas (TDG) pressures approaching 2 atm with a gas composition that it is predominantly air. Measurements of TDG pressure at well heads and in the distribution system indicated two potential mechanisms for elevated TDG pressures: (1) air entrainment during AR operations, and (2) temperature changes between the winter recharge season and the summer withdrawal season. Air entrainment during pumping was investigated by intentionally allowing the forebay (upstream reservoir) of a large pumping station to drawdown to the point of vortex formation. This resulted in up to a 0.7 atm increase in TDG pressure. In general, the solubility of gases in water decreases as the temperature increases. In the Las Vegas Valley, water that acquired a modest amount of dissolved gas during winter artificial recharge operations experienced an increase in dissolved gas pressure (0.04 atm/°C) as the water warmed in the subsurface. A combination of air entrainment during AR operations and its amplification by temperature increase after recharge can account for most of the observed amounts of excess gas at this site.

Biogeochemistry: Deep ocean iron balance

NASA Astrophysics Data System (ADS)

Homoky, William B.

2017-02-01

Dissolved iron is mysteriously pervasive in deep ocean hydrothermal plumes. An analysis of gas, metals and particles from a 4,000 km plume transect suggests that dissolved iron is maintained by rapid and reversible exchanges with sinking particles.

Modeling of Methane Migration in Shallow Aquifers from Shale Gas Well Drilling.

PubMed

Zhang, Liwei; Soeder, Daniel J

2016-05-01

The vertical portion of a shale gas well, known as the "tophole" is often drilled using an air-hammer bit that may introduce pressures as high as 2400 kPa (350 psi) into groundwater while penetrating shallow aquifers. A 3-D TOUGH2 model was used to simulate the flow of groundwater under the high hydraulic heads that may be imposed by such trapped compressed air, based on an observed case in West Virginia (USA) in 2012. The model realizations show that high-pressure air trapped in aquifers may cause groundwater to surge away from the drill site at observable velocities. If dissolved methane is present within the aquifer, the methane can be entrained and transported to a maximum distance of 10.6 m per day. Results from this study suggest that one cause of the reported increase in methane concentrations in groundwater near shale gas production wells may be the transport of pre-existing methane via groundwater surges induced by air drilling, not necessarily direct natural gas leakage from the unconventional gas reservoir. The primary transport mechanisms are advective transport of dissolved methane with water flow, and diffusive transport of dissolved methane. © 2015, National Ground Water Association.

Tracing Acetylene Dissolved in Transformer Oil by Tunable Diode Laser Absorption Spectrum.

PubMed

Ma, Guo-Ming; Zhao, Shu-Jing; Jiang, Jun; Song, Hong-Tu; Li, Cheng-Rong; Luo, Ying-Ting; Wu, Hao

2017-11-02

Dissolved gas analysis (DGA) is widely used in monitoring and diagnosing of power transformer, since the insulation material in the power transformer decomposes gases under abnormal operation condition. Among the gases, acetylene, as a symbol of low energy spark discharge and high energy electrical faults (arc discharge) of power transformer, is an important monitoring parameter. The current gas detection method used by the online DGA equipment suffers from problems such as cross sensitivity, electromagnetic compatibility and reliability. In this paper, an optical gas detection system based on TDLAS technology is proposed to detect acetylene dissolved in transformer oil. We selected a 1530.370 nm laser in the near infrared wavelength range to correspond to the absorption peak of acetylene, while using the wavelength modulation strategy and Herriott cell to improve the detection precision. Results show that the limit of detection reaches 0.49 ppm. The detection system responds quickly to changes of gas concentration and is easily to maintenance while has no electromagnetic interference, cross-sensitivity, or carrier gas. In addition, a complete detection process of the system takes only 8 minutes, implying a practical prospect of online monitoring technology.

Removing freon gas from hydraulic fluid

NASA Technical Reports Server (NTRS)

Williams, B. B.; Mitchell, S. M.; State, T. S.

1981-01-01

Dissolved freon gas is removed from hydraulic fluid by raising temperature to 150 F and bubbling dry nitrogen gas through it, even while fluid circulates through hydraulic system. Procedure reduces parts corrosion, sludge formation, and contamination.

Geochemical indicators of the origins and evolution of methane in groundwater: Gippsland Basin, Australia.

PubMed

Currell, Matthew; Banfield, Dominic; Cartwright, Ian; Cendón, Dioni I

2017-05-01

Recent expansion of shale and coal seam gas production worldwide has increased the need for geochemical studies in aquifers near gas deposits, to determine processes impacting groundwater quality and better understand the origins and behavior of dissolved hydrocarbons. We determined dissolved methane concentrations (n = 36) and δ 13 C and δ 2 H values (n = 31) in methane and groundwater from the 46,000-km 2 Gippsland Basin in southeast Australia. The basin contains important water supply aquifers and is a potential target for future unconventional gas development. Dissolved methane concentrations ranged from 0.0035 to 30 mg/L (median = 8.3 mg/L) and were significantly higher in the deep Lower Tertiary Aquifer (median = 19 mg/L) than the shallower Upper Tertiary Aquifer (median = 3.45 mg/L). Groundwater δ 13 C DIC values ranged from -26.4 to -0.4 ‰ and were generally higher in groundwater with high methane concentrations (mean δ 13 C DIC  = -9.5 ‰ for samples with >3 mg/L CH 4 vs. -16.2 ‰ in all others), which is consistent with bacterial methanogenesis. Methane had δ 13 C CH4 values of -97.5 to -31.8 ‰ and δ 2 H CH4 values of -391 to -204 ‰ that were also consistent with bacterial methane, excluding one site with δ 13 C CH4 values of -31.8 to -37.9 ‰, where methane may have been thermogenic. Methane from different regions and aquifers had distinctive stable isotope values, indicating differences in the substrate and/or methanogenesis mechanism. Methane in the Upper Tertiary Aquifer in Central Gippsland had lower δ 13 C CH4 (-83.7 to -97.5 ‰) and δ 2 H CH4 (-236 to -391 ‰) values than in the deeper Lower Tertiary Aquifer (δ 13 C CH4  = -45.8 to -66.2 ‰ and δ 2 H CH4  = -204 to -311 ‰). The particularly low δ 13 C CH4 values in the former group may indicate methanogenesis at least partly through carbonate reduction. In deeper groundwater, isotopic values were more consistent with acetate fermentation. Not all methane at a given depth and location is interpreted as being necessarily produced in situ. We propose that high dissolved sulphate concentrations in combination with high methane concentrations can indicate gas resulting from contamination and/or rapid migration as opposed to in situ bacterial production or long-term migration. Isotopes of methane and dissolved inorganic carbon (DIC) serve as further lines of evidence to distinguish methane sources. The study demonstrates the value of isotopic characterisation of groundwater including dissolved gases in basins containing hydrocarbons.

Predicting the fate of methane emanating from the seafloor using a marine two-phase gas model in one dimension (M2PG1) - Example from a known Arctic methane seep site offshore Svalbard

NASA Astrophysics Data System (ADS)

Jansson, Pär; Ferré, Benedicte

2017-04-01

Transport of methane in seawater occurs by diffusion and advection in the dissolved phase, and/or as free gas in form of bubbles. The fate of methane in bubbles emitted from the seafloor depends on both bubble size and ambient conditions. Larger bubbles can transport methane higher into the water column, potentially reaching the atmosphere and contributing to greenhouse gas concentrations and impacts. Single bubble or plume models have been used to predict the fate of bubble mediated methane gas emissions. Here, we present a new process based two-phase (free and dissolved) gas model in one dimension, which has the capability to dynamically couple water column properties such as temperature, salinity and dissolved gases with the free gas species contained in bubbles. The marine two-phase gas model in one dimension (M2PG1) uses a spectrum of bubbles and an Eulerian formulation, discretized on a finite-volume grid. It employs the most up-to-date equations for solubility and compressibility of the included gases, nitrogen, oxygen, carbon dioxide and methane. M2PG1 is an extension of PROBE (Omstedt, 2011), which facilitates atmospheric coupling and turbulence closures to realistically predict vertical mixing of all properties, including dissolved methane. This work presents the model's first application in an Arctic Ocean environment at the landward limit of the methane-hydrate stability zone west of Svalbard, where we observe substantial methane bubble release over longer time periods. The research is part of the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE) and is supported by the Research Council of Norway through its Centres of Excellence funding scheme grant No. 223259 and UiT. Omstedt, A. (2011). Guide to process based modeling of lakes and coastal seas: Springer.

The role of hydrodynamic transport in greenhouse gas fluxes at a wetland with emergent vegetation

NASA Astrophysics Data System (ADS)

Poindexter, C.; Gilson, E.; Knox, S. H.; Matthes, J. H.; Verfaillie, J. G.; Baldocchi, D. D.; Variano, E. A.

2013-12-01

In wetlands with emergent vegetation, the hydrodynamic transport of dissolved gases is often neglected because emergent plants transport gases directly and limit wind-driven air-water gas exchange by sheltering the water surface. Nevertheless, wetland hydrodynamics, and thermally-driven stirring in particular, have the potential to impact gas fluxes in these environments. We are evaluating the importance of hydrodynamic dissolved gas transport at a re-established marsh on Twitchell Island in the Sacramento-San Joaquin Delta (California, USA). At this marsh, the U.S. Geological Survey has previously observed rapid accumulation of organic material (carbon sequestration) as well as very high methane emissions. To assess the role of hydrodynamics in the marsh's greenhouse gas fluxes, we measured dissolved carbon dioxide and methane in the water column on a bi-weekly basis beginning in July 2012. We employed a model for air-water gas fluxes in wetlands with emergent vegetation that predicts gas transfer velocities from meteorological conditions. Modeled air-water gas fluxes were compared with net gas fluxes measured at the marsh via the eddy covariance technique. This comparison revealed that hydrodynamic transport due to thermal convection was responsible for approximately one third of net carbon dioxide and methane fluxes. The cooling at the water surface driving thermal convection occurred each night and was most pronounced during the warmest months of the year. These finding have implications for the prediction and management of greenhouse gas fluxes at re-established marshes in the Sacramento-San Joaquin Delta and other similar wetlands.

Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary.

PubMed

Zhao, Zhen; Tang, Jianhui; Mi, Lijie; Tian, Chongguo; Zhong, Guangcai; Zhang, Gan; Wang, Shaorui; Li, Qilu; Ebinghaus, Ralf; Xie, Zhiyong; Sun, Hongwen

2017-12-01

Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral ∑PFASs were within the range of 76-551pg/m 3 . Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral ∑PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral ∑PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition were simulated for neutral PFASs, and neutral ∑PFASs fluxes varied from 0.37 to 2.3pg/m 2 /s. In the dissolved phase of the surface water, concentrations of ionic ∑PFASs ranged from 1.6 to 118ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic ∑PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic ∑PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs. Copyright © 2017 Elsevier B.V. All rights reserved.

High-pressure sorption of nitrogen, carbon dioxide, and their mixtures on Argonne Premium Coals

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

Andreas Busch; Yves Gensterblum; Bernhard M. Krooss

2007-06-15

Gas sorption isotherms have been measured for carbon dioxide and nitrogen and their binary mixture (N{sub 2}/CO{sub 2} {approximately} 80/20) on three different moisture-equilibrated coals from the Argonne Premium Coal Sample Program by the U.S. Department of Energy, varying in rank from 0.25 to 1.68% vitrinite reflectance (VR{sub r}). The measurements were conducted at 55 C and at pressures up to 27 MPa for the pure gases and up to 10 MPa for the gas mixture. The effects of the large differences in equilibrium moisture contents (0.8 to 32.2%) on sorption capacity were estimated on the basis of the aqueousmore » solubility of CO{sub 2} and N{sub 2} at experimental conditions. Especially for the Beulah-Zap coal with an equilibrium moisture content of {approximately} 32%, the amount of dissolved CO{sub 2} contributes significantly to the overall storage capacity, whereas the amounts of N{sub 2} dissolved in the moisture water are low and can be neglected. Sorption measurements with nitrogen/carbon dioxide mixtures showed very low capacities for N{sub 2}. For Illinois coal, these excess sorption values were even slightly negative, probably due to small volumetric effects (changes in condensed phase volume). The evolution of the composition of the free gas phase in contact with the coal sample has been monitored continuously during each pressure step of the sorption tests. This composition changed strongly over time. Apparently, CO{sub 2} reaches sorption sites very quickly initially and is subsequently partly replaced by N{sub 2} molecules until concentration equilibration is reached. 18 refs., 10 figs., 2 tabs.« less

Geochemical variations during the 2012 Emilia seismic sequence

NASA Astrophysics Data System (ADS)

Sciarra, Alessandra; Cantucci, Barbara; Galli, Gianfranco; Cinti, Daniele; Pizzino, Luca

2015-04-01

Several geochemical surveys (soil gas and shallow water) were performed in the Modena province (Massa Finalese, Finale Emilia, Medolla and S. Felice sul Panaro), during 2006-2014 period. In May-June 2012, a seismic sequence (main shocks of ML 5.9 and 5.8) was occurred closely to the investigated area. In this area 300 CO2 and CH4 fluxes measurements, 150 soil gas concentrations (He, H2, CO2, CH4 and C2H6), 30 shallow waters and their isotopic analyses (δ13C- CH4, δD- CH4 and δ13C- CO2) were performed in April-May 2006, October and December 2008, repeated in May and September 2012, June 2013 and July 2014 afterwards the 2012 Emilia seismic sequences. Chemical composition of soil gas are dominated by CH4 in the southern part by CO2 in the northern part. Very anomalous fluxes and concentrations are recorded in spot areas; elsewhere CO2 and CH4 values are very low, within the typical range of vegetative and of organic exhalation of the cultivated soil. After the seismic sequence the CH4 and CO2 fluxes are increased of one order of magnitude in the spotty areas, whereas in the surrounding area the values are within the background. On the contrary, CH4 concentration decrease (40%v/v in the 2012 surveys) and CO2 concentration increase until to 12.7%v/v (2013 survey). Isotopic gas analysis were carried out only on samples with anomalous values. Pre-seismic data hint a thermogenic origin of CH4 probably linked to leakage from a deep source in the Medolla area. Conversely, 2012/2013 isotopic data indicate a typical biogenic origin (i.e. microbial hydrocarbon production) of the CH4, as recognized elsewhere in the Po Plain and surroundings. The δ13C-CO2 value suggests a prevalent shallow origin of CO2 (i.e. organic and/or soil-derived) probably related to anaerobic oxidation of heavy hydrocarbons. Water samples, collected from domestic, industrial and hydrocarbons exploration wells, allowed us to recognize different families of waters. Waters are meteoric in origin and, apart one sample, are not thermally anomalous. Stable isotopes of H and O point out the absence of mixing with connate waters, prolonged interaction with the host-rock at high temperature and/or heavy gas-water exchange at depth. Isotopic carbon composition emphasizes its organic (i.e. shallow) origin; only "La Canonica" site, the deepest well sampled in this study, shows a probable deep(er) provenance of dissolved carbon. Waters trend away from the atmospheric end-member composition, dissolving CO2 or CH4 depending on their redox state. Dissolved radon activity is very low, likely due to the particular hydrogeological setting of the study area (i.e. the presence of waters with long residence times in the considered aquifers). Obtained results highlight a different behavior before and after the seismic events, proved also by the different carbon isotopic signature of CH4. These variations could be produced by increasing of bacterial (e.g. peat strata) and methanogenic fermentation processes in the first meters of the soil.

Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans

USGS Publications Warehouse

Pohlman, John; Waite, William F.; Bauer, James E.; Osburn, Christopher L.; Chapman, N. Ross

2011-01-01

Marine sediments contain about 500–10,000 Gt of methane carbon1, 2, 3, primarily in gas hydrate. This reservoir is comparable in size to the amount of organic carbon in land biota, terrestrial soils, the atmosphere and sea water combined1, 4, but it releases relatively little methane to the ocean and atmosphere5. Sedimentary microbes convert most of the dissolved methane to carbon dioxide6, 7. Here we show that a significant additional product associated with microbial methane consumption is methane-derived dissolved organic carbon. We use Δ14C and δ13C measurements and isotopic mass-balance calculations to evaluate the contribution of methane-derived carbon to seawater dissolved organic carbon overlying gas hydrate-bearing seeps in the northeastern Pacific Ocean. We show that carbon derived from fossil methane accounts for up to 28% of the dissolved organic carbon. This methane-derived material is much older, and more depleted in 13C, than background dissolved organic carbon. We suggest that fossil methane-derived carbon may contribute significantly to the estimated 4,000–6,000 year age of dissolved organic carbon in the deep ocean8, and provide reduced organic matter and energy to deep-ocean microbial communities.

Linking carbon and hydrologic fluxes in the critical zone: Observations from high-frequency monitoring of a weathered bedrock vadose zone

NASA Astrophysics Data System (ADS)

Tune, A. K.; Druhan, J. L.; Wang, J.; Cargill, S.; Murphy, C.; Rempe, D. M.

2017-12-01

A principle challenge in quantifying feedbacks between continental weathering and atmospheric CO2 is to improve understanding of how biogeochemical processes in the critical zone influence the distribution and mobility of organic and inorganic carbon. In particular, in landscapes characterized by thin soils and heterogeneous weathered and fractured bedrock, little data exist to inform and constrain predictive models for carbon dynamics. Here, we present the results of an intensive water and gas sampling campaign across an 18 m thick, variably saturated argillite weathering profile in the Eel River CZO. We monitor water content in situ and regularly collect samples of freely-draining water, tightly-held water, and gas through wet and dry seasons using a novel Vadose-zone Monitoring System (VMS) consisting of sensors and samplers distributed across a 20 m long inclined borehole. This novel approach facilitates the interception of gas and water during transport across the entire variably saturated weathering profile. The data demonstrate that seasonal changes in saturation control the vertical distribution and mobility of carbon in the fractured critical zone. Concentrations of gaseous CO2, O2, and dissolved organic and inorganic carbon fluctuate significantly and repeatably with seasonal additions of water infiltrating the weathered bedrock. A persistent vertical structure in the concentrations of dissolved phases and gas concentrations broadly corresponds to depths associated with unsaturated, seasonally saturated, and chronically saturated zones. Associated variations in the vertical structure of mineralogy and elemental composition, including solid phase organic carbon content, are observed in core obtained during drilling. Together, our observations indicate significant respiration of organic carbon at depths greater than the base of the soil, and thus motivate further investigation of the role of heterogeneous weathered, bedrock environments, which are needed to improve quantitative models for feedbacks between terrestrial and atmospheric CO2.

Hydro-geochemical impact of CO2 leakage from geological storage on shallow potable aquifers: A field scale pilot experiment.

NASA Astrophysics Data System (ADS)

Cahill, A.; Jakobsen, R.

2012-04-01

In order to assess the environmental implications of leakage of CO2 from a geological sequestration site into overlying shallow potable aquifers, a 3 month field release experiment is planned to commence in spring 2012 at Vrøgum plantation, Western Denmark. To test the injection and sampling methodologies and as a study of short term effects, a pilot experiment was conducted at the field site: 45 kg of food grade CO2 was injected at 10 m depth over 48 hours into an unconfined, aeolian/glacial sand aquifer and the effects on water chemistry studied. The CO2 was injected through an inclined well installed with a 1 m length of porous polyethylene well screen (20 µm pore size) initially at a rate of 5 litres per minute increasing to 10 litres per minute after 24 hours. Water samples were taken from a network of multi-level sample points (8, 4 and 2.4m depth) before, during and after the injection and measured for physico-chemical parameters and major/trace element composition. Although the site possesses a relatively high hydraulic conductivity (12-16 m/day), due to the small hydraulic gradient (0.0039) 6 days elapsed before effects of CO2 on the ground water were detected in the first sampling point located 0.5 m down flow from the injection well. The dissolved plume of CO2 was observed only in the 8 m depth sample points and moved with flow (approximately 0.10 - 0.12 m/day). The plume spread laterally to 2m width as little as 1 m from the injection screen after 26 days, indicating that CO2 bubbles change the hydraulics of the medium. Dissolved CO2 was not detected in sample points at 4 or 2.4 m depth at any time during the experiment, suggesting gas could not move into the slightly finer grained upper sand. Effects of CO2 dissolution at 8 m depth were manifest as a clear and stable increase in electrical conductivity (approximately 160 to 300 µS/cm), a relatively small increase in total dissolved ions (approximately 30 to 50 mg/l) and an unstable depression of pH (approximately 5.8 to 4.73). The dissolved CO2 plume evolved with a distinct maximal front observed to pass through sample points followed by a slowly dissipating tail. After 56 days the CO2 plume reached the end of the monitoring network and was at its greatest extent (5 m length by 1 m width) however still appeared to be increasing in size suggesting residual gas phase CO2 trapped within the pore space continuously dissolving. Water quality did not significantly deteriorate and only small increases in major and trace elements were observed. Overall, groundwater chemistry results indicate that for an aquifer composed primarily of slowly reacting silicate sediments, such as Vrøgum, the risks to water resources from a short term leak from CCS into shallow overlying aquifers are minimal. However, a potential accumulation effect within the plume front as it moves through the formation was observed inferring a large scale leak may develop a CO2 charged plume exceeding guideline values for major and trace elements.

WE-FG-206-07: Assessing the Lung Function of Patients with Non-Small Cell Lung Cancer Using Hyperpolarized Xenon-129 Dissolved-Phase MRI

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

Qing, K; Mugler, J; Chen, Q

Purpose: Hyperpolarized xenon-129 dissolved-phase MRI is the first imaging technique that allows 3-dimensional regional mapping of ventilation and gas uptake by tissue and blood the in human lung. Multiple outcome measures can be produced from this method. Existing studies in subjects with major lung diseases compared to healthy controls demonstrated high sensitivities of this method to pulmonary physiological factors including ventilation, alveolar tissue density, surface-to-volume ratio, pulmonary perfusion and gas-blood barrier thickness. The purpose of this study is to evaluate the utility of this new imaging tool to assess the lung function in patients with non-small cell lung cancer (NSCLC).more » Methods: Ten healthy controls (age: 63±10) and five patients (age: 62±13) with NSCLC underwent the xenon-129 dissolved-phase MRI, pulmonary function test (PFT) and CT for clinical purpose. Three outcome measures were produced from xenon-129 dissolved-phase MRI, including ventilation defect fraction (Vdef%) reflecting the airflow obstruction, tissue-to-gas ratio reflecting lung tissue density, and RBC-to-tissue ratio reflecting pulmonary perfusion and gas exchange. Results: Compared to healthy controls, patients with NSCLC showed more ventilation defects (NSCLC: 22±6%; control: 40±18%; P=0.01), lower tissue-to-gas (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.05) and RBC-to-tissue ratios (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.01). Maps for ventilation and gas uptake by tissue and blood were highly heterogeneous in the lungs of patients. Vdef% and RBC-to-tissue ratios in all 15 subjects correlated with corresponding global lung functional measures from PFT: FEV1/FVC (R=−0.91, P<0.001) and DLCO % predicted (R=0.54, P=0.03), respectively. The tissue-to-gas ratios correlated with tissue density (HU) measured by CT (R=0.88, P<0.001). Conclusion: With the unique ability to provide detailed information about lung function including ventilation, tissue density, perfusion and gas exchange with 3D resolution, hyperpolarized xenon-129 dissolved-phase MRI has high potential to be used as an important reference for radiotherapy treatment planning and for evaluating the side effects of the treatment. Receive research support and funding from Siemens.« less

Measuring temporal variability in pore-fluid chemistry to assess gas hydrate stability: development of a continuous pore-fluid array.

PubMed

Lapham, Laura L; Chanton, Jeffrey P; Martens, Christopher S; Higley, Paul D; Jannasch, Hans W; Woolsey, J Robert

2008-10-01

A specialized pore-fluid array (PFA) sampler was designed to collect and store pore fluids to monitor temporal changes of ions and gases in gas hydrate bearing sediments. We tested the hypothesis that pore-fluid chemistry records hydrate formation or decomposition events and reflects local seismic activity. The PFA is a seafloor probe that consists of an interchangeable instrument package that houses OsmoSamplers, long-term pore-fluid samplers, a specialized low-dead volume fluid coupler, and eight sample ports along a 10 m sediment probe shaft. The PFA was deployed at Mississippi Canyon 118, a Gulf of Mexico hydrate site. A 170 day record was acquired from the overlying water and 1.3 m below seafloor (mbsf). Fluids were measured for dissolved chloride, sulfate, and methane concentrations and dissolved inorganic carbon and methane stable carbon and deuterium isotope ratios. Chloride and sulfate did not change significantly over time, suggesting the absence of gas hydrate formation or decomposition events. Over the temporal record, methane concentrations averaged 4 mM at 1.3 mbsf, and methane was thermogenic in origin (delta13C-CH4 = -32.4 +/- 3.4 per thousand). The timing of an anomalous 14 mM methane spike coincided with a nearby earthquake (Mw = 5.8), consistent with the hypothesis that pore-fluid chemistry reflects seismic events.

Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

NASA Astrophysics Data System (ADS)

Poindexter, C.; Variano, E. A.

2010-12-01

Flow around arrays of cylinders at low and intermediate Reynolds numbers has been studied numerically, analytically and experimentally. Early results demonstrated that at flow around randomly oriented cylinders exhibits reduced turbulent length scales and reduced diffusivity when compared to similarly forced, unimpeded flows (Nepf 1999). While horizontal dispersion in flows through cylinder arrays has received considerable research attention, the case of vertical dispersion of reactive constituents has not. This case is relevant to the vertical transfer of dissolved gases in wetlands with emergent vegetation. We present results showing that the presence of vegetation can significantly enhance vertical transport, including gas transfer across the air-water interface. Specifically, we study a wind-sheared air-water interface in which randomly arrayed cylinders represent emergent vegetation. Wind is one of several processes that may govern physical dispersion of dissolved gases in wetlands. Wind represents the dominant force for gas transfer across the air-water interface in the ocean. Empirical relationships between wind and the gas transfer coefficient, k, have been used to estimate spatial variability of CO2 exchange across the worlds’ oceans. Because wetlands with emergent vegetation are different from oceans, different model of wind effects is needed. We investigated the vertical transport of dissolved oxygen in a scaled wetland model built inside a laboratory tank equipped with an open-ended wind tunnel. Plastic tubing immersed in water to a depth of approximately 40 cm represented emergent vegetation of cylindrical form such as hard-stem bulrush (Schoenoplectus acutus). After partially removing the oxygen from the tank water via reaction with sodium sulfite, we used an optical probe to measure dissolved oxygen at mid-depth as the tank water re-equilibrated with the air above. We used dissolved oxygen time-series for a range of mean wind speeds to estimate the gas transfer coefficient, k, for both a vegetated condition and a control condition (no cylinders). The presence of cylinders in the tank substantially increased the rate of the gas transfer. For the highest wind speed, the gas transfer coefficient was several times higher when cylinders were present compared to when they were not. The gas transfer coefficient for the vegetated condition also proved sensitive to wind speed, increasing markedly with increasing mean wind speeds. Profiles of dissolved oxygen revealed well-mixed conditions in the bulk water column following prolonged air-flow above the water surface, suggesting application of the thin-film model is appropriate. The enhanced gas exchange observed might be explained by increased turbulent kinetic energy within the water column and the anisotropy of the cylinder array, which constrains horizontal motions more than vertical motions. Improved understanding of gas exchange in vegetated water columns may be of particularly use to investigations of carbon fluxes and soil accretion in wetlands. Reference: Nepf, H. (1999), Drag, turbulence, and diffusion in flow through emergent vegetation, Water Resour. Res., 35(2), 479-489.

Hydrocarbon-Rich Groundwater above Shale-Gas Formations: A Karoo Basin Case Study.

PubMed

Eymold, William K; Swana, Kelley; Moore, Myles T; Whyte, Colin J; Harkness, Jennifer S; Talma, Siep; Murray, Ricky; Moortgat, Joachim B; Miller, Jodie; Vengosh, Avner; Darrah, Thomas H

2018-03-01

Horizontal drilling and hydraulic fracturing have enhanced unconventional hydrocarbon recovery but raised environmental concerns related to water quality. Because most basins targeted for shale-gas development in the USA have histories of both active and legacy petroleum extraction, confusion about the hydrogeological context of naturally occurring methane in shallow aquifers overlying shales remains. The Karoo Basin, located in South Africa, provides a near-pristine setting to evaluate these processes, without a history of conventional or unconventional energy extraction. We conducted a comprehensive pre-industrial evaluation of water quality and gas geochemistry in 22 groundwater samples across the Karoo Basin, including dissolved ions, water isotopes, hydrocarbon molecular and isotopic composition, and noble gases. Methane-rich samples were associated with high-salinity, NaCl-type groundwater and elevated levels of ethane, 4 He, and other noble gases produced by radioactive decay. This endmember displayed less negative δ 13 C-CH 4 and evidence of mixing between thermogenic natural gases and hydrogenotrophic methane. Atmospheric noble gases in the methane-rich samples record a history of fractionation during gas-phase migration from source rocks to shallow aquifers. Conversely, methane-poor samples have a paucity of ethane and 4 He, near saturation levels of atmospheric noble gases, and more negative δ 13 C-CH 4 ; methane in these samples is biogenic and produced by a mixture of hydrogenotrophic and acetoclastic sources. These geochemical observations are consistent with other basins targeted for unconventional energy extraction in the USA and contribute to a growing data base of naturally occurring methane in shallow aquifers globally, which provide a framework for evaluating environmental concerns related to unconventional energy development (e.g., stray gas). © 2018, National Ground Water Association.

Influence of addition of degassed water on bulk nanobubbles.

PubMed

Tuziuti, Toru; Yasui, Kyuichi; Kanematsu, Wataru

2018-05-01

The effects of the addition of degassed water on bulk nanobubbles (ultrafine bubbles) of air in liquid water were investigated by measuring the volumetric concentration and size distribution at different dissolved air degree of saturation (DOS) values. The proportion of degassed water mixed with water containing bulk nanobubbles was increased to prepare samples having lower DOS values. It was found that the volumetric concentration of nanobubbles mostly decreased and the average nanobubble size became larger as the DOS was decreased. In our proposed mechanism, smaller nanobubbles are selectively dissolved into the surrounding liquid by Laplace pressure due to surface tension as the DOS is reduced. These results demonstrate that stable bulk nanobubbles are present even in water undersaturated with gas. The role of nanobubble under an ultrasound is also discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

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

Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B.

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flowmore » rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.« less

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

NASA Astrophysics Data System (ADS)

Prasetyaningrum, A.; Ratnawati, Jos, B.

2015-12-01

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O3) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

Methods for recovering a polar solvent from a fluid stream contaminated with at least one polar impurity

DOEpatents

Ginosar, Daniel M.; Wendt, Daniel S.

2012-11-13

A method of removing a polar solvent from a fluid volume contaminated with at least one polar impurity, such as a free fatty acid, is provided. The method comprises providing a fluid volume that includes at least one polar impurity dissolved in at least one solvent. The fluid volume is contacted with an expanding gas to remove the at least one solvent. The expanding gas may be dissolved into the at least one solvent in the fluid volume to form a gas-expanded solvent. The immiscibility of the polar impurities in the gas-expanded solvent enables separation of the polar impurities from the gas-expanded solvent. After separation of the polar impurities, at least one of the temperature and pressure may be reduced to separate the solvent from the expanding gas such that the clean solvent may be reused.

Flue gas desulfurization/denitrification using metal-chelate additives

DOEpatents

Harkness, J.B.L.; Doctor, R.D.; Wingender, R.J.

1985-08-05

A method of simultaneously removing SO/sub 2/ and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO/sub 2/ and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled. 3 figs.

Total dissolved gas and water temperature in the lower Columbia River, Oregon and Washington, 2006: Quality-assurance data and comparison to water-quality standards

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.; Johnston, Matthew W.

2006-01-01

For the eight monitoring stations in water year 2006, an average of 99.1% of the total-dissolved-gas data were received in real time by the USGS satellite downlink and were within 1% saturation of the expected value on the basis of calibration data, replicate quality-control measurements in the river, and comparison to ambient river conditions at adjacent stations. 

Total dissolved gas and water temperature in the lower Columbia River, Oregon and Washington, 2005: quality-assurance data and comparison to water-quality standards

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.; Johnston, Matthew W.

2005-01-01

For the eight monitoring sites in water year 2005, an average of 98.2% of the total-dissolved-gas data were received in real time by the USGS satellite downlink and were within 1% saturation of the expected value, based on calibration data, replicate quality-control measurements in the river, and comparison to ambient river conditions at adjacent sites. 

Total dissolved gas and water temperature in the lower Columbia river, Oregon and Washington, 2004: quality-assurance data and comparison to water-quality standards

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.; Johnston, Matthew

2004-01-01

For the seven monitoring sites used to regulate spill in water year 2004, an average of 99.0% of the total- dissolved-gas data were received in real time by the USGS satellite downlink and were within 1% saturation of the expected value, based on calibration data, replicate quality-control measurements in the river, and comparison to ambient river conditions at adjacent sites.

Baseline groundwater quality in national park units within the Marcellus and Utica Shale gas plays, New York, Pennsylvania, and West Virginia, 2011

USGS Publications Warehouse

Eckhardt, David A.V.; Sloto, Ronald A.

2012-01-01

Groundwater samples were collected from 15 production wells and 1 spring at 9 national park units in New York, Pennsylvania, and West Virginia in July and August 2011 and analyzed to characterize the quality of these water supplies. The sample sites generally were selected to represent areas of potential effects on water quality by drilling and development of gas wells in Marcellus Shale and Utica Shale areas of the northeastern United States. The groundwater samples were analyzed for 53 constituents, including nutrients, major inorganic constituents, trace elements, chemical oxygen demand, radioactivity, and dissolved gases, including methane and radon-222. Results indicated that the groundwater used for water supply at the selected national park units is generally of acceptable quality, although concentrations of some constituents exceeded at least one drinking-water guideline at several wells. Nine analytes were detected in concentrations that exceeded Federal drinking-water standards, mostly secondary standards that define aesthetic properties of water, such as taste and odor. One sample had an arsenic concentration that exceeded the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 10 micrograms per liter (μg/L). The pH, which is a measure of acidity (hydrogen ion activity), ranged from 4.8 to 8.4, and in 5 of the 16 samples, the pH values were outside the accepted U.S. Environmental Protection Agency secondary maximum contaminant level (SMCL) range of 6.5 to 8.5. The concentration of total dissolved solids exceeded the SMCL of 500 milligrams per liter (mg/L) at four sites. The sulfate concentration exceeded the SMCL of 250 mg/L concentration in one sample, and the fluoride concentration exceeded the SMCL of 2 mg/L in one sample. Sodium concentrations exceeded the U.S. Environmental Protection Agency drinking water health advisory of 60 mg/L at four sites. Iron concentrations exceeded the SMCL of 300 μg/L in two samples, and manganese concentrations exceeded the SMCL of 50 μg/L in five samples. Radon-222 concentrations exceeded the proposed U.S. Environmental Protection Agency MCL of 300 picocuries per liter in eight samples.

Malignant human cell transformation of Marcellus Shale gas drilling flow back water.

PubMed

Yao, Yixin; Chen, Tingting; Shen, Steven S; Niu, Yingmei; DesMarais, Thomas L; Linn, Reka; Saunders, Eric; Fan, Zhihua; Lioy, Paul; Kluz, Thomas; Chen, Lung-Chi; Wu, Zhuangchun; Costa, Max; Zelikoff, Judith

2015-10-01

The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carried out to define the LC50 values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. Copyright © 2015 Elsevier Inc. All rights reserved.

Ground-water monitoring plan, water quality, and variability of agricultural chemicals in the Missouri River alluvial aquifer near the City of Independence, Missouri, well field, 1998-2000

USGS Publications Warehouse

Kelly, Brian P.

2002-01-01

A detailed ground-water sampling plan was developed and executed for 64 monitoring wells in the city of Independence well field to characterize ground-water quality in the 10-year zone of contribution. Samples were collected from monitoring wells, combined Independence well field pumpage, and the Missouri River at St. Joseph, Missouri, from 1998 through 2000. In 328 ground-water samples from the 64 monitoring wells and combined well field pumpage samples, specific conductance values ranged from 511 to 1,690 microsiemens per centimeter at 25 degrees Celsius, pH values ranged from 6.4 to 7.7, water temperature ranged from 11.3 to 23.6 degrees Celsius, and dissolved oxygen concentrations ranged from 0 to 3.3 milligrams per liter. In 12 samples from the combined well field pumpage samples, specific conductance values ranged from 558 to 856 microsiemens per centimeter at 25 degrees Celsius, pH values ranged from 6.9 to 7.7, water temperature ranged from 5.8 to 22.9 degrees Celsius, and dissolved oxygen concentrations ranged from 0 to 2.4 milligrams per liter. In 45 Missouri River samples, specific conductance values ranged from 531 to 830 microsiemens per centimeter at 25 degrees Celsius, pH ranged from 7.2 to 8.7, water temperature ranged from 0 to 30 degrees Celsius, and dissolved oxygen concentrations ranged from 5.0 to 17.6 milligrams per liter. The secondary maximum contaminant level for sulfate in drinking water was exceeded once in samples from two monitoring wells, the maximum contaminant level (MCL) for antimony was exceeded once in a sample from one monitoring well, and the MCL for barium was exceeded once in a sample from one monitoring well. The MCL for iron was exceeded in samples from all monitoring wells except two. The MCL for manganese was exceeded in all samples from monitoring wells and combined well field pumpage. Enzyme linked immunoassay methods indicate total benzene, toluene, ethyl benzene, and xylene (BTEX) was detected in samples from five wells. The highest total BTEX concentration was less than the MCL of toluene, ethyl benzene, or xylene but greater than the MCL for benzene. Total BTEX was not detected in samples from any well more than once. Atrazine was detected in samples from nine wells, and exceeded the MCL once in a sample from one well. Alachlor was detected in samples from 22 wells but the MCL was never exceeded in any sample. Samples from five wells analyzed for a large number of organic compounds indicate concentrations of volatile organic compounds did not exceed the MCL for drinking water. No semi-volatile organic compounds were detected; dieldrin was detected in one well sample, and no other pesticides, herbicides, polychlorinated biphenyls, or polychlorinated napthalenes were detected. Dissolved ammonia, dissolved nitrite plus nitrate, dissolved orthophosphorus, alachlor, and atrazine analyses were used to determine the spatial and temporal variability of agricultural chemicals in ground water. Detection frequencies for dissolved ammonia increased with well depth, decreased with depth for dissolved nitrite plus nitrate, and remained relatively constant with depth for dissolved orthophosphorus. Maximum concentrations of dissolved ammonia, dissolved nitrite plus nitrate, and dissolved orthophosphorus were largest in the shallowest wells and decreased with depth, which may indicate the land surface as the source. However, median concentrations increased with depth for dissolved ammonia, were less than the detection limit for dissolved nitrite plus nitrate, and decreased with depth for dissolved orthophosphorus. This pattern does not indicate a well-defined single source for these constituents. Dissolved orthophosphorus median concentrations were similar, but decreased slightly with depth, and may indicate the land surface as the source. Seasonal variability of dissolved ammonia, dissolved nitrite plus nitrate, a

Mass-size distribution and concentration of metals from personal exposure to arc welding fume in pipeline construction: a case report.

PubMed

Yang, Show-Yi; Lin, Jia-Ming; Young, Li-Hao; Chang, Ching-Wen

2018-04-07

We investigate exposure to welding fume metals in pipeline construction, which are responsible for severe respiratory problems. We analyzed air samples obtained using size-fractioning cascade impactors that were attached to the welders performing shielded metal and gas tungsten arc welding outdoors. Iron, aluminum, zinc, chromium, manganese, copper, nickel, and lead concentrations in the water-soluble (WS) and water-insoluble (WI) portions were determined separately, using inductively coupled plasma mass spectrometry. The mass-size distribution of welding fume matches a log-normal distribution with two modes. The metal concentrations in the welding fume were ranked as follows: Fe > Al > Zn > Cr > Mn > Ni > Cu > Pb. In the WS portion, the capacities of metals dissolving in water are correlated with the metal species but particle sizes. Particularly, Zn, Mn, and Pb exhibit relatively higher capacities than Cu, Cr, Al, Fe, and Ni. Exposure of the gas-exchange region of the lungs to WS metals were in the range of 4.9% to 34.6% of the corresponding metals in air by considering the particle-size selection in lungs, metal composition by particle size, and the capacities of each metal dissolving in water.

Vertical and temporal dynamics of cyanobacteria in the Carpina potable water reservoir in northeastern Brazil.

PubMed

Moura, A N; Dantas, E W; Oliveira, H S B; Bittencourt-Oliveira, M C

2011-05-01

This study analysed vertical and temporal variations of cyanobacteria in a potable water supply in northeastern Brazil. Samples were collected from four reservoir depths in the four months; September and December 2007; and March and June 2008. The water samples for the determination of nutrients and cyanobacteria were collected using a horizontal van Dorn bottle. The samples were preserved in 4% formaldehyde for taxonomic analysis using an optical microscope, and water aliquots were preserved in acetic Lugol solution for determination of density using an inverted microscope. High water temperatures, alkaline pH, low transparency, high phosphorous content and limited nitrogen content were found throughout the study. Dissolved oxygen stratification occurred throughout the study period whereas temperature stratification occurred in all sampling months, with the exception of June. No significant vertical differences were recorded for turbidity or total and dissolved forms of nutrients. There were high levels of biomass arising from Planktothrix agardhii, Cylindrospermopsis raciborskii, Geitlerinema amphibium and Pseudanabaena catenata. The study demonstrates that, in a tropical eutrophic environment with high temperatures throughout the water column, perennial multi-species cyanobacterial blooms, formed by species capable of regulating their position in the water column (those that have gas vesicles for buoyancy), are dominant in the photic and aphotic strata.

A selective and sensitive optical sensor for dissolved ammonia detection via agglomeration of fluorescent Ag nanoclusters and temperature gradient headspace single drop microextraction.

PubMed

Dong, Jiang Xue; Gao, Zhong Feng; Zhang, Ying; Li, Bang Lin; Li, Nian Bing; Luo, Hong Qun

2017-05-15

In this paper, a simple sensor platform is presented for highly selective and sensitive detection of dissolved ammonia in aqueous solutions without pretreatment based on temperature gradient headspace single drop microextraction (HS-SDME) technique, and fluorescence and UV-vis spectrophotometry are utilized with the Ag nanoclusters (Ag NCs) functioned by citrate and glutathione as the probe. The sensing mechanism is based on the volatility of ammonia gas and the active response of Ag NCs to pH change caused by the introduction of ammonia. High pH can make the Ag NCs agglomerate and lead to the obvious decrease of fluorescence intensity and absorbance of Ag NCs solution. Moreover, the presented method exhibits a remarkably high selectivity toward dissolved ammonia over most of inorganic ions and amino acid, and shows a good linear range of 10-350μM (0.14-4.9mgNL -1 ) with a low detection limit of 336nM (4.70μgNL -1 ) at a signal-to-noise ratio of 3. In addition, the practical applications of the sensor have been successfully demonstrated by detecting dissolved ammonia in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Land Disturbance Associated with Oil and Gas Development and Effects of Development-Related Land Disturbance on Dissolved-Solids Loads in Streams in the Upper Colorado River Basin, 1991, 2007, and 2025

USGS Publications Warehouse

Buto, Susan G.; Kenney, Terry A.; Gerner, Steven J.

2010-01-01

Oil and gas resource development in the Upper Colorado River Basin (UCRB) has increased substantially since the year 2000. The UCRB encompasses several significant oil and gas producing areas that have the potential for continued oil and gas resource development. Land disturbance associated with oil and gas resource development is caused by activities related to constructing drill pads to contain drilling and well maintenance equipment and roads to access the drill pad. Land disturbed by oil and gas development has the potential to cause increased erosion, stream degradation, habitat fragmentation and alteration, and increase public use of areas that may be environmentally sensitive. Land disturbance resulting from oil and gas resource development has not been monitored and mapped on a regional scale in the UCRB. However, information on the location and age of oil and gas wells in the UCRB is available. These data combined with geographic data analysis and modeling techniques were used to estimate the total area of disturbed land associated with oil and gas resource development in 1991 and in 2007 in the UCRB. Additional information about anticipated oil and gas development in the UCRB was used to project land disturbance to the year 2025. Results of the analysis indicate that approximately 117,500 acres (183 mi2) of total land disturbance was associated with drill pads and related roads in the UCRB in 1991. The estimated area of disturbed land associated with oil and gas development increased 53 percent to 179,400 acres (280 mi2) in 2007. Projecting oil and gas development through 2025 results in a potential near doubling of the land surface disturbance to approximately 319,300 acres (500 mi2). Estimated land disturbance for 1991 and 2007 were input to a contaminant transport model developed for the UCRB to assess the statistical significance of energy-related land disturbance to contributing dissolved solids to basin streams. The statistical assessment was an observational study based on an existing model and available water-quality monitoring data for the basin. No new data were collected for the analysis. The source coefficient calibrated for the disturbed lands associated with oil and gas development in 2007 was zero, which indicated that estimated land disturbance from oil and gas development is not statistically significant in explaining dissolved solids in UCRB streams. The lack of significance in the contaminant transport modeling framework may be due to the amount of available monitoring data, the spatial distribution of monitoring sites with respect to land disturbance, or the overall quantity of land disturbance associated with oil and gas development basin wide. Finally, dissolved-solids loads derived from natural landscapes may be similar to loads derived from lands disturbed by oil and gas resource development. The model recalibration done for this study confirms calibration results from Kenney and others (2009): the most significant contributor to dissolved solids in the UCRB is irrigated agricultural land, which covers an area substantially larger than the estimated area disturbed by oil and gas development and is subjected to artificially applied water.

Assessing the occurrence and distribution of pyrethroids in water and suspended sediments

USGS Publications Warehouse

Hladik, M.L.; Kuivila, K.M.

2009-01-01

The distribution of pyrethroid insecticides in the environment was assessed by separately measuring concentrations in the dissolved and suspended sediment phases of surface water samples. Filtered water was extracted by HLB solid-phase extraction cartridges, while the sediment on the filter was sonicated and cleaned up using carbon and aluminum cartridges. Detection limits for the 13 pyrethroids analyzed by gas chromatography-tandem mass spectrometry were 0.5 to 1 ng L-1 for water and 2 to 6 ng g for the suspended sediments. Seven pyrethroids were detected in six water samples collected from either urban or agricultural creeks, with bifenthrin detected the most frequently and at the highest concentrations. In spiked water samples and field samples, the majority of the pyrethroids were associated with the suspended sediments.

A multi-residue method for the analysis of pesticides and pesticide degradates in water using HLB solid-phase extraction and gas chromatography-ion trap mass spectrometry

USGS Publications Warehouse

Hladik, M.L.; Smalling, K.L.; Kuivila, K.M.

2008-01-01

A method was developed for the analysis of over 60 pesticides and degradates in water by HLB solid-phase extraction and gas-chromatography/mass spectrometry. Method recoveries and detection limits were determined using two surface waters with different dissolved organic carbon (DOC) concentrations. In the lower DOC water, recoveries and detection limits were 80%-108% and 1-12 ng/L, respectively. In the higher DOC water, the detection limits were slightly higher (1-15 ng/L). Additionally, surface water samples from four sites were analyzed and 14 pesticides were detected with concentrations ranging from 4 to 1,200 ng/L. ?? 2008 Springer Science+Business Media, LLC.

A System for Incubations at High Gas Partial Pressure

PubMed Central

Sauer, Patrick; Glombitza, Clemens; Kallmeyer, Jens

2012-01-01

High-pressure is a key feature of deep subsurface environments. High partial pressure of dissolved gasses plays an important role in microbial metabolism, because thermodynamic feasibility of many reactions depends on the concentration of reactants. For gases, this is controlled by their partial pressure, which can exceed 1 MPa at in situ conditions. Therefore, high hydrostatic pressure alone is not sufficient to recreate true deep subsurface in situ conditions, but the partial pressure of dissolved gasses has to be controlled as well. We developed an incubation system that allows for incubations at hydrostatic pressure up to 60 MPa, temperatures up to 120°C, and at high gas partial pressure. The composition and partial pressure of gasses can be manipulated during the experiment. To keep costs low, the system is mainly made from off-the-shelf components with only very few custom-made parts. A flexible and inert PVDF (polyvinylidene fluoride) incubator sleeve, which is almost impermeable for gases, holds the sample and separates it from the pressure fluid. The flexibility of the incubator sleeve allows for sub-sampling of the medium without loss of pressure. Experiments can be run in both static and flow-through mode. The incubation system described here is usable for versatile purposes, not only the incubation of microorganisms and determination of growth rates, but also for chemical degradation or extraction experiments under high gas saturation, e.g., fluid–gas–rock-interactions in relation to carbon dioxide sequestration. As an application of the system we extracted organic compounds from sub-bituminous coal using H2O as well as a H2O–CO2 mixture at elevated temperature (90°C) and pressure (5 MPa). Subsamples were taken at different time points during the incubation and analyzed by ion chromatography. Furthermore we demonstrated the applicability of the system for studies of microbial activity, using samples from the Isis mud volcano. We could detect an increase in sulfate reduction rate upon the addition of methane to the sample. PMID:22347218

Titan Lake Probe: The Ongoing NASA Decadal Study Preliminary Report

NASA Astrophysics Data System (ADS)

Waite, J. Hunter; Brockwell, Tim; Elliot, John; Reh, Kim; Spencer, John; Outer Planets Satellites Decadal Subpanel, The

2010-05-01

This talk provides an update on the scientific requirements and preliminary design of a Titan Lake Probe for a future NASA Flagship mission. The starting point for this study is the joint NASA ESA TSSM mission. Using this as a starting point we have revisited the scientific requirements and expanded them to include the possibility of a lake floater and a submersible. The preliminary results of this ongoing study will be presented. The scientific objectives of a Titan Lake Probe mission are: 1) to understand the formation and evolution of Titan and its atmosphere through measurement of the composition of the target lake (e.g., Kraken Mare), with particular emphasis on the isotopic composition of dissolved minor species and on dissolved noble gases, 2) to study the lake-atmosphere interaction in order to determine the role of Titan's lakes in the methane cycle, 3) to investigate the target lake as a laboratory for both pre-biotic organic chemistry in both water (or ammonia-enriched water) solutions and non-water solvents, and 4) to determine if Titan has an interior ocean by measuring tidal changes in the level of the lake over the course of Titan's sixteen-day orbit. The driving requirements for the mission are: 1) the need to land on and explore the lake at depth while adequately communicating the data back to Earth via either direct to Earth or relay communications, 2) thermal design that allows sustained (>32 days) sampling of the 94K lake environment, and 3) a mass spectrometer inlet system that allows sampling of gas, liquid, and solids from the 94K environment. The primary payload is an analytical chemistry laboratory that includes an inlet system for sampling gas, liquid, and solids in and above the lake feeding two capable mass spectrometers that determine the organic and isotopic composition of the sampled materials. The instrumentation also includes a meteorological package that can measure the rate of gas exchange between the lake and the atmosphere, and a lake physical characteristics package that includes pressure and temperature measurements as well as sonar.

Method for detecting coliform organisms

NASA Technical Reports Server (NTRS)

Nishioka, K.; Nibley, D. A.; Jeffers, E. L.; Brooks, R. L. (Inventor)

1983-01-01

A method and apparatus are disclosed for determining the concentration of coliform bacteria in a sample. The sample containing the coliform bacteria is cultured in a liquid growth medium. The cultured bacteria produce hydrogen and the hydrogen is vented to a second cell containing a buffer solution in which the hydrogen dissolves. By measuring the potential change in the buffer solution caused by the hydrogen, as a function of time, the initial concentration of bacteria in the sample is determined. Alternatively, the potential change in the buffer solution can be compared with the potential change in the liquid growth medium to verify that the potential change in the liquid growth medium is produced primarily by the hydrogen gas produced by the coliform bacteria.

Analysis of maximum allowable fragment heights during dissolution of high flux isotope reactor fuel in an h-canyon dissolver

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

Daniel, G.; Rudisill, T.

2017-07-17

As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U 3O 8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H 2. The HFIR fuel cores will be dissolved using a flowsheet developed by the Savannahmore » River National Laboratory (SRNL) in either the 6.4D or 6.1D dissolver using a unique insert. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The recovered U will be down-blended into low-enriched U for subsequent use as commercial reactor fuel. During the development of the HFIR fuel dissolution flowsheet, the cycle time for the initial core was estimated at 28 to 40 h. Once the cycle is complete, H-Canyon personnel will open the dissolver and probe the HFIR insert wells to determine the height of any fuel fragments which did not dissolve. Before the next core can be charged to the dissolver, an analysis of the potential for H 2 gas generation must show that the combined surface area of the fuel fragments and the subsequent core will not generate H 2 concentrations in the dissolver offgas which exceeds 60% of the lower flammability limit (LFL) of H 2 at 200 °C. The objective of this study is to identify the maximum fuel fragment height as a function of the Al concentration in the dissolving solution which will provide criteria for charging successive HFIR cores to an H-Canyon dissolver.« less

Lateral line pore diameters correlate with the development of gas bubble trauma signs in several Columbia River fishes

USGS Publications Warehouse

Morris, R.G.; Beeman, J.W.; VanderKooi, S.P.; Maule, A.G.

2003-01-01

Gas bubble trauma (GBT) caused by gas supersaturation of river water continues to be a problem in the Columbia River Basin. A common indicator of GBT is the percent of the lateral line occluded with gas bubbles; however, this effect has never been examined in relation to lateral line morphology. The effects of 115, 125 and 130% total dissolved gas levels were evaluated on five fish species common to the upper Columbia River. Trunk lateral line pore diameters differed significantly (P<0.0001) among species (longnose sucker>largescale sucker>northern pikeminnow≥chinook salmon≥redside shiner). At all supersaturation levels evaluated, percent of lateral line occlusion exhibited an inverse correlation to pore size but was not generally related to total dissolved gas level or time of exposure. This study suggests that the differences in lateral line pore diameters between species should be considered when using lateral line occlusion as an indicator of gas bubble trauma.

Pesticides in Water and Suspended Sediment of the Alamo and New Rivers, Imperial Valley/Salton Sea Basin, California, 2006-2007

USGS Publications Warehouse

Orlando, James L.; Smalling, Kelly L.; Kuivila, Kathryn

2008-01-01

Water and suspended-sediment samples were collected at eight sites on the Alamo and New Rivers in the Imperial Valley/Salton Sea Basin of California and analyzed for both current-use and organochlorine pesticides by the U.S. Geological Survey. Samples were collected in the fall of 2006 and spring of 2007, corresponding to the seasons of greatest pesticide use in the basin. Large-volume water samples (up to 650 liters) were collected at each site and processed using a flow-through centrifuge to isolate suspended sediments. One-liter water samples were collected from the effluent of the centrifuge for the analysis of dissolved pesticides. Additional samples were collected for analysis of dissolved organic carbon and for suspended-sediment concentrations. Water samples were analyzed for a suite of 61 current-use and organochlorine pesticides using gas chromatography/mass spectrometry. A total of 25 pesticides were detected in the water samples, with seven pesticides detected in more than half of the samples. Dissolved concentrations of pesticides observed in this study ranged from below their respective method detection limits to 8,940 nanograms per liter (EPTC). The most frequently detected compounds in the water samples were chlorpyrifos, DCPA, EPTC, and trifluralin, which were observed in more than 75 percent of the samples. The maximum concentrations of most pesticides were detected in samples from the Alamo River. Maximum dissolved concentrations of carbofuran, chlorpyrifos, diazinon, and malathion exceeded aquatic life benchmarks established by the U.S. Environmental Protection Agency for these pesticides. Suspended sediments were analyzed for 87 current-use and organochlorine pesticides using microwave-assisted extraction, gel permeation chromatography for sulfur removal, and either carbon/alumina stacked solid-phase extraction cartridges or deactivated Florisil for removal of matrix interferences. Twenty current-use pesticides were detected in the suspended-sediment samples, including pyrethroid insecticides and fungicides. Fourteen legacy organochlorine pesticides also were detected in the suspended-sediment samples. Greater numbers of current-use and organochlorine pesticides were observed in the Alamo River samples in comparison with the New River samples. Maximum concentrations of current-use pesticides in suspended-sediment samples ranged from below their method detection limits to 174 micrograms per kilogram (pendimethalin). Most organochlorine pesticides were detected at or below their method detection limits, with the exception of p,p'-DDE, which had a maximum concentration of 54.2 micrograms per kilogram. The most frequently detected current-use pesticides in the suspended-sediment samples were chlorpyrifos, permethrin, tetraconazole, and trifluralin, which were observed in more than 83 percent of the samples. The organochlorine degradates p,p'-DDD and p,p'-DDE were detected in all suspended-sediment samples.

Electrochemistry of single nanobubbles. Estimating the critical size of bubble-forming nuclei for gas-evolving electrode reactions.

PubMed

German, Sean R; Edwards, Martin A; Chen, Qianjin; Liu, Yuwen; Luo, Long; White, Henry S

2016-12-12

In this article, we address the fundamental question: "What is the critical size of a single cluster of gas molecules that grows and becomes a stable (or continuously growing) gas bubble during gas evolving reactions?" Electrochemical reactions that produce dissolved gas molecules are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, and often lead to the formation of gaseous bubbles. Herein, we demonstrate that electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of an individual nanobubble of H 2 , N 2 , or O 2 at a Pt nanodisk electrode, can be analyzed using classical thermodynamic relationships (Henry's law and the Young-Laplace equation - including non-ideal corrections) to provide an estimate of the size of the gas bubble nucleus that grows into a stable bubble. We further demonstrate that this critical nucleus size is independent of the radius of the Pt nanodisk employed (<100 nm radius), and weakly dependent on the nature of the gas. For example, the measured critical surface concentration of H 2 of ∼0.23 M at the instant of bubble formation corresponds to a critical H 2 nucleus that has a radius of ∼3.6 nm, an internal pressure of ∼350 atm, and contains ∼1700 H 2 molecules. The data are consistent with stochastic fluctuations in the density of dissolved gas, at or near the Pt/solution interface, controlling the rate of bubble nucleation. We discuss the growth of the nucleus as a diffusion-limited process and how that process is affected by proximity to an electrode producing ∼10 11 gas molecules per second. Our study demonstrates the advantages of studying a single-entity, i.e., an individual nanobubble, in understanding and quantifying complex physicochemical phenomena.

The effects of dissolved gas supersaturation on white sturgeon larvae

USGS Publications Warehouse

Counihan, T.D.; Miller, Allen I.; Mesa, M.G.; Parsley, M.J.

2000-01-01

Spill at dams has caused supersaturation of atmospheric gas in waters of the Columbia and Snake rivers and raised concerns about the effects of dissolved gas supersaturation (DGS) on white sturgeons Acipenser transmontanus. The timing and location of white sturgeon spawning and the dispersal of white sturgeon larvae from incubation areas makes the larval stage potentially vulnerable to the effects of DGS. To assess the effects of DGS on white sturgeon larvae, we exposed larvae to mean total dissolved gas (TDG) levels of 118% and 131% saturation in laboratory bioassay tests. Gas bubble trauma (GBT) was manifested as a gas bubble in the buccal cavity, nares, or both and it first occurred at developmental stages characterized by the formation of the mouth and gills. Exposure times of 15 min were sufficient to elicit these signs in larvae in various stages of development. No mortality was observed in larvae exposed to 118% TDG for 10 d, but 50% mortality occurred after a 13-d exposure to 131% TDG. The signs of GBT we observed resulted in positive buoyancy and alterations in behavior that may affect the dispersal and predation vulnerability of white sturgeon larvae. The exact depth distribution of dispersing white sturgeon larvae in the Columbia River currently is unknown. Thus, our results may represent a worst-case scenario if white sturgeon larvae are dispersed at depths with insufficient hydrostatic pressure to compensate for high TDG levels.

Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid

NASA Astrophysics Data System (ADS)

Roy, James W.; Smith, James E.

2007-01-01

Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid.

PubMed

Roy, James W; Smith, James E

2007-01-30

Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

Interaction between phases in the liquid–gas system

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

Berry, R. S., E-mail: bmsmirnov@gmail.com; Smirnov, B. M.

This work analyzes the equilibrium between a liquid and a gas over this liquid separated by an interface. Various gas forms exist inside the liquid: dissolved gas molecules attached to solvent molecules, free gas molecules, and gaseous bubbles. Thermodynamic equilibrium is maintained between two phases; the first phase is the liquid containing dissolved and free molecules, and the second phase is the gas over the liquid and bubbles inside it. Kinetics of gas transition between the internal and external gas proceeds through bubbles and includes the processes of bubbles floating up and bubble growth as a result of association duemore » to the Smoluchowski mechanism. Evolution of a gas in the liquid is considered using the example of oxygen in water, and numerical parameters of this system are given. In the regime under consideration for an oxygen–water system, transport of oxygen into the surrounding air proceeds through micron-size bubbles with lifetimes of hours. This regime is realized if the total number of oxygen molecules in water is small compared with the numbers of solvated and free molecules in the liquid.« less

Dissolved gasesous hydrocarbons in shallow groundwater of Lower Saxony, Germany - Revisited 2016

NASA Astrophysics Data System (ADS)

Schloemer, Stefan; Illing, Christian J.; Blumenberg, Martin; Oest, Johanna; Elbracht, Jörg

2017-04-01

Many concerns arise within the public and government/political institutions over potential groundwater contamination from deep drilling operations. For this reason we initiated a baseline study in 2014 on the distribution of dissolved methane, ethane and propane in shallow groundwater ( 1000 groundwater wells, Schloemer et al., 2016) of Lower Saxony, which includes the major petroleum and natural gas provinces in Germany. We observed a variation of dissolved methane concentration over 7 orders of magnitude (20 nl/l to 60 ml/l [v/v]). Methane delta13C compositions ranged from -110‰ to +25‰ vs VPDB, narrowly clustering around -70‰ at high concentrations but being increasingly more variable at lower concentrations (-40‰ to -80‰)). Most of the data are clearly indicative for methanogenic processes, samples unusually enriched in delta13C can best be explained by secondary methane oxidation. Although some general regional trend can be observed, results are highly variable within short lateral distances or within different aquifers/filter depths. Frequently ethane (27% of samples, median 50nl/l) and occasionally propane (8%, median 23nl/l) has been detected. Lacking the carbon isotope composition of these homologues and thus solely based on the extremely low concentrations and atypical ethane/propane ratios, these have been tentatively interpreted as ubiquitous microbial background. From the original 2014 sample set around 100 wells have been selected for consecutive testing through 2015. In spring 2016 a total number of 1100 wells have been sampled, 700 of which had already been part of the initial study, providing us with the unique opportunity to assess long term variations. The overall comparison of these 700 samples revealed only small relative variations in methane concentrations (mostly < ± 25%), although higher variations are common at concentrations less than 1 µl/l. Correspondingly the carbon isotopic composition of paired samples is quite stable (± 2‰)) for most of the samples ( 60%) but large discrepancies can be observed at low absolute concentrations (> ± 5‰ in 25% of samples). Minor variations could be related to uncertainties in laboratory analysis (± 10% in concentration, ± 0.5‰ delta13C). To which extent the small number of sampled groundwater with unusually high variations are indeed a result of a naturally occurring process (rapidly changing conditions or anthropogenic influence) is currently under investigation. However, applying different sampling conditions/procedures (i.e. different pumps, flow rates) had to be accepted during the course of the project and might be a reason as well. In any case our preliminary results point toward the necessity of repeated sampling (particularly in shallow unconfined aquifers) to account for possible natural variations and of strictly consistent sampling protocols when analyzing "non-conservative" dissolved gases. Reference Schloemer, S., Elbracht, J., Blumenberg, M. and Illing, C.J., 2016. Distribution and origin of dissolved methane, ethane and propane in shallow groundwater of Lower Saxony, Germany. Applied Geochemistry, 67: 118-132.

Evidence for the enhanced lability of dissolved organic matter following permafrost slope disturbance in the Canadian High Arctic

NASA Astrophysics Data System (ADS)

Woods, Gwen C.; Simpson, Myrna J.; Pautler, Brent G.; Lamoureux, Scott F.; Lafrenière, Melissa J.; Simpson, André J.

2011-11-01

Arctic landscapes are believed to be highly sensitive to climate change and accelerated disturbance of permafrost is expected to significantly impact the rate of carbon cycling. While half the global soil organic matter (SOM) is estimated to reside in Arctic soils, projected warmer temperatures and permafrost disturbance will release much of this SOM into waterways in the form of dissolved organic matter (DOM). The spring thaw and subsequent flushing of soils releases the highest contributions of DOM annually but has historically been undersampled due to the difficulties of sampling during this period. In this study, passive samplers were placed throughout paired High Arctic watersheds during the duration of the 2008 spring flush in Nunavut, Canada. The watersheds are very similar with the exception of widespread active layer detachments (ALDs) that occurred within one of the catchments during a period of elevated temperatures in the summer of 2007. DOM samples were analyzed for structural and spectral characteristics via nuclear magnetic resonance (NMR) and fluorescence spectroscopy as well as vulnerability to degradation with simulated solar exposure. Lignin-derived phenols were further assessed utilizing copper(II) oxide (CuO) oxidation and gas chromatography/mass spectrometry (GC/MS). The samples were found to have very low dissolved lignin phenol content (˜0.07% of DOC) and appear to originate from primarily non-woody angiosperm vegetation. The acid/aldehyde ratios for dissolved vanillyl phenols were found to be high (up to 3.6), indicating the presence of highly oxidized lignin. Differences between DOM released from the ALD vs. the undisturbed watershed suggest that these shallow detachment slides have significantly impacted the quality of Arctic DOM. Although material released from the disturbed catchment was found to be highly oxidized, DOM in the lake into which this catchment drained had chemical characteristics indicating high contributions from microbial and/or primary productivity. The resulting pool of dissolved carbon within the lake appears to be more biologically- and photochemically-labile than material from the undisturbed system. These disturbances may have implications for projected climate warming; sustained elevated temperatures would likely perpetuate widespread ALDs and further affect carbon cycling in this environment.

Water and bed-sediment quality in the vicinity of Berlin Lake, Ohio, 2001

USGS Publications Warehouse

Darner, Robert A.

2002-01-01

Berlin Lake, in northeast Ohio, was created by the U.S. Army Corps of Engineers in 1943 and is used primarily for flood control for the upper reaches of the Mahoning River. The area surrounding and under the lake has been tapped for oil and natural gas production. One of the by-products of oil and gas production is concentrated salt water or brine, which might have an effect on the chemical quality of area potable-water sources. This report presents the results of a U.S. Geological Survey baseline study to collect current (2001) water and sediment-quality data and to characterize water quality in the Berlin Lake watershed. Chloride-to-bromide ratios were used to detect the presence of brine in water samples and to indicate possible adverse effects on water quality. Analyses of ground-water samples from domestic wells in the area indicate a source of chloride and bromide, but defining the source would require more data collection. Analyses of specific conductance and dissolved solids indicate that 78 percent (14 of 18) of the ground-water samples exceeded the Secondary Maximum Contaminant Level for dissolved solids in public water supplies of 500 milligrams per liter (mg/L), compared to 6 percent of samples exceeding 500 mg/L in two nearby studies. Surface water was analyzed twice, once each during low-flow and surface runoff conditions. A comparison of the 2001 data to historical chloride concentrations, accounting for seasonal changes, does not indicate an increase in chloride loads for surface water in the area of Berlin Lake. Polycyclic aromatic hydrocarbons were found in bed-sediment samples collected from the mouths of major tributaries to Berlin Lake. Polycyclic aromatic hydrocarbons are produced during the incomplete combustion of organic carbon materials such as wood and fossil fuels, and they are components of petroleum products.

Total dissolved gas and water temperature in the lower Columbia River, Oregon and Washington, 2003: Quality-assurance data and comparison to water-quality standards

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.; Johnston, Matthew W.

2003-01-01

The variances to the States of Oregon and Washington water-quality standards for total dissolved gas were exceeded at six of the seven monitoring sites. The sites at Camas and Bonneville forebay had the most days exceeding the variance of 115% saturation. The forebay exceedances may have been the result of the cumulative effects of supersaturated water moving downstream through the lower Columbia River. Apparently, the levels of total dissolved gas did not decrease rapidly enough downstream from the dams before reaching the next site. From mid-July to mid-September, water temperatures were usually above 20 degrees Celsius at each of the seven lower Columbia River sites. According to the Oregon water-quality standard, when the temperature of the lower Columbia River exceeds 20 degrees Celsius, no measurable temperature increase resulting from anthropogenic activities is allowed. Transient increases of about 1 degree Celsius were noted at the John Day forebay site, due to localized solar heating.

Study on the Removal of Gases in RH Refining Progress through Experiments Using Vacuum Induction Furnace

NASA Astrophysics Data System (ADS)

Niu, Deliang; Liu, Qingcai; Wang, Zhu; Ren, Shan; Lan, Yuanpei; Xu, Minren

Removal of gas is the major function of RH degasser. To optimize the RH refining craft in Chongqing Iron and Steel Co. Ltd, the degassing effect of RH degasser at different degrees of vacuum was investigated using a vacuum induction furnace. In addition, the effect of processing time on the gas content dissolved in molten steel was also studied. The results showed that degree of vacuum was one of the important factors that determined the degassing efficiency in RH refining process. High vacuum degree is helpful in the removal of gas, especially in the removal of [H] dissolved in molten steel. The processing time could be reduced from 25-30 min to 15 minutes and gas content could also meet the demand of RH refining.

Technical note: In vitro total gas and methane production measurements from closed or vented rumen batch culture systems.

PubMed

Cattani, M; Tagliapietra, F; Maccarana, L; Hansen, H H; Bailoni, L; Schiavon, S

2014-03-01

This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane concentration was influenced by feed but not by the T × F interaction. Corrected CH4 production was influenced by feed, but not by venting technique or the T × F interaction. Closed bottles provide good measurements of CH4 production but not of GP. Venting of bottles at low pressure permits a reliable evaluation of total GP and CH4 production. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Radium content of oil- and gas-field produced waters in the northern Appalachian Basin (USA)—Summary and discussion of data

USGS Publications Warehouse

Rowan, E.L.; Engle, M.A.; Kirby, C.S.; Kraemer, T.F.

2011-01-01

Radium activity data for waters co-produced with oil and gas in New York and Pennsylvania have been compiled from publicly available sources and are presented together with new data for six wells, including one time series. When available, total dissolved solids (TDS), and gross alpha and gross beta particle activities also were compiled. Data from the 1990s and earlier are from sandstone and limestone oil/gas reservoirs of Cambrian-Mississippian age; however, the recent data are almost exclusively from the Middle Devonian Marcellus Shale. The Marcellus Shale represents a vast resource of natural gas the size and significance of which have only recently been recognized. Exploitation of the Marcellus involves hydraulic fracturing of the shale to release tightly held gas. Analyses of the water produced with the gas commonly show elevated levels of salinity and radium. Similarities and differences in radium data from reservoirs of different ages and lithologies are discussed. The range of radium activities for samples from the Marcellus Shale (less than detection to 18,000 picocuries per liter (pCi/L)) overlaps the range for non-Marcellus reservoirs (less than detection to 6,700 pCi/L), and the median values are 2,460 pCi/L and 734 pCi/L, respectively. A positive correlation between the logs of TDS and radium activity can be demonstrated for the entire dataset, and controlling for this TDS dependence, Marcellus shale produced water samples contain statistically more radium than non-Marcellus samples. The radium isotopic ratio, Ra-228/Ra-226, in samples from the Marcellus Shale is generally less than 0.3, distinctly lower than the median values from other reservoirs. This ratio may serve as an indicator of the provenance or reservoir source of radium in samples of uncertain origin.

The evolution of Devonian hydrocarbon gases in shallow aquifers of the northern Appalachian Basin: Insights from integrating noble gas and hydrocarbon geochemistry

NASA Astrophysics Data System (ADS)

Darrah, Thomas H.; Jackson, Robert B.; Vengosh, Avner; Warner, Nathaniel R.; Whyte, Colin J.; Walsh, Talor B.; Kondash, Andrew J.; Poreda, Robert J.

2015-12-01

The last decade has seen a dramatic increase in domestic energy production from unconventional reservoirs. This energy boom has generated marked economic benefits, but simultaneously evoked significant concerns regarding the potential for drinking-water contamination in shallow aquifers. Presently, efforts to evaluate the environmental impacts of shale gas development in the northern Appalachian Basin (NAB), located in the northeastern US, are limited by: (1) a lack of comprehensive ;pre-drill; data for groundwater composition (water and gas); (2) uncertainty in the hydrogeological factors that control the occurrence of naturally present CH4 and brines in shallow Upper Devonian (UD) aquifers; and (3) limited geochemical techniques to quantify the sources and migration of crustal fluids (specifically methane) at various time scales. To address these questions, we analyzed the noble gas, dissolved ion, and hydrocarbon gas geochemistry of 72 drinking-water wells and one natural methane seep all located ≫1 km from shale gas drill sites in the NAB. In the present study, we consciously avoided groundwater wells from areas near active or recent drilling to ensure shale gas development would not bias the results. We also intentionally targeted areas with naturally occurring CH4 to characterize the geochemical signature and geological context of gas-phase hydrocarbons in shallow aquifers of the NAB. Our data display a positive relationship between elevated [CH4], [C2H6], [Cl], and [Ba] that co-occur with high [4He]. Although four groundwater samples show mantle contributions ranging from 1.2% to 11.6%, the majority of samples have [He] ranging from solubility levels (∼45 × 10-6 cm3 STP/L) with below-detectable [CH4] and minor amounts of tritiogenic 3He in low [Cl] and [Ba] waters, up to high [4He] = 0.4 cm3 STP/L with a purely crustal helium isotopic end-member (3He/4He = ∼0.02 times the atmospheric ratio (R/Ra)) in samples with CH4 near saturation for shallow groundwater (P(CH4) = ∼1 atmosphere) and elevated [Cl] and [Ba]. These data suggest that 4He is dominated by an exogenous (i.e., migrated) crustal source for these hydrocarbon gas- and salt-rich fluids. In combination with published inorganic geochemistry (e.g., 87Sr/86Sr, Sr/Ba, Br-/Cl-), new noble gas and hydrocarbon isotopic data (e.g., 20Ne/36Ar, C2+/C1, δ13C-CH4) suggest that a hydrocarbon-rich brine likely migrated from the Marcellus Formation (via primary hydrocarbon migration) as a dual-phase fluid (gas + liquid) and was fractionated by solubility partitioning during fluid migration and emplacement into conventional UD traps (via secondary hydrocarbon migration). Based on the highly fractionated 4He/CH4 data relative to Marcellus and UD production gases, we propose an additional phase of hydrocarbon gas migration where natural gas previously emplaced in UD hydrocarbon traps actively diffuses out into and equilibrates with modern shallow groundwater (via tertiary hydrocarbon migration) following uplift, denudation, and neotectonic fracturing. These data suggest that by integrating noble gas geochemistry with hydrocarbon and dissolved ion chemistry, one can better determine the source and migration processes of natural gas in the Earth's crust, which are two critical factors for understanding the presence of hydrocarbon gases in shallow aquifers.

Using high resolution measurements of gas tracers to determine metabolic rates in streams

NASA Astrophysics Data System (ADS)

Knapp, J. L.; Osenbrück, K.; Brennwald, M. S.; Cirpka, O. A.

2017-12-01

Hyporheic exchange and other hyporheic processes are strongly linked to stream respiration, as the majority of a streams' microorganisms are located within the streambed. Directly estimating these respiration rates on the reach scale is usually not possible, but they can indirectly be inferred from measurements of dissolved oxygen. This, however, requires determining stream reaeration rates with high precision. Conducting gas-tracer tests has been found to be the most reliable method to estimate stream reaeration, but the majority of field-based sampling techniques for tracer gases are either costly in time and materials, or imprecise. By contrast, on-site gas analysis using gas-equilibrium membrane-inlet mass spectrometers (miniRUEDI, Gasometrix GmbH [1]) avoid the errors caused by sampling, storage, and analysis in the standard sampling techniques. Furthermore, the high analytical frequency of the on-site mass-spectrometer provides concentration data exhibiting a low uncertainty. We present results from gas-tracer tests with a continuous injection of propane and noble gases as tracers in a number of small streams. The concentrations of the tracer gases are recorded continuously over time at the first measurement station to account for fluctuations of the input signal, whereas shorter sample sets are collected at all further measurement stations. Reaeration rate constants are calculated from gas measurements for individual stream sections. These rates are then used to estimate metabolic rates of respiration and primary production based on time series of oxygen measurements. To demonstrate the advancement of the method provided by the on-site analysis, results from measurements performed by on-site mass spectroscopy are compared to those from traditional headspace sampling with gas chromatography analysis. Additionally, differences in magnitude and uncertainty of the obtained reaeration rates of oxygen and calculated metabolic rates from both methods highlight the usefulness of the high-frequency on-site analysis. [1] Brennwald, M. S., Schmidt, M., Oser, J., and Kipfer, R. (2016). A portable and autonomous mass spectrometric system for on-site environmental gas analysis. Environ. Sci. Technol., 50(24):13455-13463. Doi: 10.1021/acs.est.6b03669

Hydrology of Northern Utah Valley, Utah County, Utah, 1975-2005

USGS Publications Warehouse

Cederberg, Jay R.; Gardner, Philip M.; Thiros, Susan A.

2009-01-01

The ground-water resources of northern Utah Valley, Utah, were assessed during 2003-05 to describe and quantify components of the hydrologic system, determine a hydrologic budget for the basin-fill aquifer, and evaluate changes to the system relative to previous studies. Northern Utah Valley is a horst and graben structure with ground water occurring in both the mountain-block uplands surrounding the valley and in the unconsolidated basin-fill sediments. The principal aquifer in northern Utah Valley occurs in the unconsolidated basin-fill deposits where a deeper unconfined aquifer occurs near the mountain front and laterally grades into multiple confined aquifers near the center of the valley. Sources of water to the basin-fill aquifers occur predominantly as either infiltration of streamflow at or near the interface of the mountain front and valley or as subsurface inflow from the adjacent mountain blocks. Sources of water to the basin-fill aquifers were estimated to average 153,000 (+/- 31,500) acre-feet annually during 1975-2004 with subsurface inflow and infiltration of streamflow being the predominant sources. Discharge from the basin-fill aquifers occurs in the valley lowlands as flow to waterways, drains, ditches, springs, as diffuse seepage, and as discharge from flowing and pumping wells. Ground-water discharge from the basin-fill aquifers during 1975-2004 was estimated to average 166,700 (+/- 25,900) acre-feet/year where discharge to wells for consumptive use and discharge to waterways, drains, ditches, and springs were the principal sources. Measured water levels in wells in northern Utah Valley declined an average of 22 feet from 1981 to 2004. Water-level declines are consistent with a severe regional drought beginning in 1999 and continuing through 2004. Water samples were collected from 36 wells and springs throughout the study area along expected flowpaths. Water samples collected from 34 wells were analyzed for dissolved major ions, nutrients, and stable isotopes of hydrogen and oxygen. Water samples from all 36 wells were analyzed for dissolved-gas concentration including noble gases and tritium/helium-3. Within the basin fill, dissolved-solids concentration generally increases with distance along flowpaths from recharge areas, and shallower flowpaths tend to have higher concentrations than deeper flowpaths. Nitrate concentrations generally are at or below natural background levels. Dissolved-gas recharge temperature data support the conceptual model of the basin-fill aquifers and highlight complexities of recharge patterns in different parts of the valley. Dissolved-gas data indicate that the highest elevation recharge sources for the basin-fill aquifer are subsurface inflow derived from recharge in the adjacent mountain block between the mouths of American Fork and Provo Canyons. Apparent ground-water ages in the basin-fill aquifer, as calculated using tritium/helium-3 data, range from 2 to more than 50 years. The youngest waters in the valley occur near the mountain fronts with apparent ages generally increasing near the valley lowlands and discharge area around Utah Lake. Flowpaths are controlled by aquifer properties and the location of the predominant recharge sources, including subsurface inflow and recharge along the mountain front. Subsurface inflow is distributed over a larger area across the interface of the subsurface mountain block and basin-fill deposits. Subsurface inflow occurs at a depth deeper than that at which mountain-front recharge occurs. Recharge along the mountain front is often localized and focused over areas where streams and creeks enter the valley, and recharge is enhanced by the associated irrigation canals.

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades

PubMed Central

Kletetschka, Gunther; Hruba, Jolana

2015-01-01

Abstract Three issues are critical for successful cryopreservation of multicellular material: gases dissolved in liquid, thermal conductivity of the tissue, and localization of microstructures. Here we show that heat distribution is controlled by the gas amount dissolved in liquids and that when changing the liquid into solid, the dissolved gases either form bubbles due to the absence of space in the lattice of solids and/or are migrated toward the concentrated salt and sugar solution at the cost of amount of heat required to be removed to complete a solid-state transition. These factors affect the heat distribution in the organs to be cryopreserved. We show that the gas concentration issue controls fracturing of ice when freezing. There are volumetric changes not only when changing the liquid into solid (volume increases) but also reduction of the volume when reaching lower temperatures (volume decreases). We discuss these issues parallel with observations of the cryosurvivability of multicellular organisms, tardigrades, and discuss their analogy for cryopreservation of large organs. PMID:26309797

Dissolved Gases and Ice Fracturing During the Freezing of a Multicellular Organism: Lessons from Tardigrades.

PubMed

Kletetschka, Gunther; Hruba, Jolana

2015-01-01

Three issues are critical for successful cryopreservation of multicellular material: gases dissolved in liquid, thermal conductivity of the tissue, and localization of microstructures. Here we show that heat distribution is controlled by the gas amount dissolved in liquids and that when changing the liquid into solid, the dissolved gases either form bubbles due to the absence of space in the lattice of solids and/or are migrated toward the concentrated salt and sugar solution at the cost of amount of heat required to be removed to complete a solid-state transition. These factors affect the heat distribution in the organs to be cryopreserved. We show that the gas concentration issue controls fracturing of ice when freezing. There are volumetric changes not only when changing the liquid into solid (volume increases) but also reduction of the volume when reaching lower temperatures (volume decreases). We discuss these issues parallel with observations of the cryosurvivability of multicellular organisms, tardigrades, and discuss their analogy for cryopreservation of large organs.

Evaluation of the Giggenbach bottle method using artificial fumarolic gases

NASA Astrophysics Data System (ADS)

Lee, S.; Jeong, H. Y.

2013-12-01

Volcanic eruption is one of the most dangerous natural disasters. Mt. Baekdu, located on the border between North Korea and China, has been recently showing multiple signs of its eruption. The magmatic activity of a volcano strongly affects the composition of volcanic gases, which can provide a useful tool for predicting the eruption. Among various volcanic gas monitoring methods, the Giggenbach bottle method involves the on-site sampling of volcanic gases and the subsequent laboratory analysis, thus making it possible to detect a range of volcanic gases at low levels. In this study, we aim to evaluate the effectiveness of the Giggenbach bottle method and develop the associated analytical tools using artificial fumarolic gases with known compositions. The artificial fumarolic gases are generated by mixing CO2, CO, H2S, SO2, Ar, and H2 gas streams with a N2 stream sparged through an acidic medium containing HCl and HF. The target compositions of the fumarolic gases are selected to cover those reported for various volcanoes under different tectonic environments as follows: CO2 (2-12 mol %), CO (0.3-1 mol %), H2S (0.7-2 mol %), SO2 (0.6-4 mol %), Ar (0.3-0.7 mol %), H2 (0.3-0.7 mol %), HCl (0.2-1 mol %), and HF (< 0.015 mol %). The artificial fumarolic gases are collected into an evacuated bottle partially filled with 4 M NaOH solution containing 0.5 mM Cd(CH3COO)2. While non-condensable components such as CO, Ar, H2, and N2 accumulate in the headspace of the bottle, acidic components including CO2, SO2, HCl, and HF dissolve into the alkaline solution. In case of H2S, it reacts with dissolved Cd2+ to precipitate as CdS(s). The gas accumulated in the headspace can be analyzed for CO, Ar, H2, and N2 on a gas chromatography. The alkaline solution is first separated from yellowish CdS precipitates by filtration, and then pretreated with hydrogen peroxide to oxidize dissolved SO2 (H2SO3) to SO42-. The resultant solution can be analyzed for SO2 as SO42-, HCl as Cl-, and HF as F- on an ion chromatography and CO2 on an ionic carbon analyzer. Also, the amount of H2S can be determined by measuring the remaining dissolved Cd2+ on an inductively coupled plasma-mass spectrometry.

Isotope hydrology of voluminous cold springs in fractured rock from an active volcanic region, northeastern California

NASA Astrophysics Data System (ADS)

Roses, Timothy P.; Lee Davisson, M.; Criss, Robert E.

1996-05-01

The more than 1550 km2 (600 mi2) Hat Creek Basin in northeastern California is host to several first magnitude cold springs that emanate from Quaternary basaltic rocks with individual discharge rates ranging from 1.7 to 8.5 m3 s-1 (60-300 ft3 s-1). Stable isotope (δ18O, δD, δ13C) and 14C measurements of surface and groundwater samples were used to identify recharge areas, and to evaluate aquifer residence times and flow paths. Recharge locations were constrained from the regional decrement in meteoric water δ18O values as a function of elevation, determined to be -0.23‰ per 100 m for small springs and creek waters collected along the western Cascade slope of this region. In general, the large-volume springs are lower in (δ18O than surrounding meteoric waters, and are inferred to originate in high-elevation, high-precipitation regions up to 50 km away from their discharge points. Large spring 14C abundances range from 99 to 41 % modern carbon (pmc), and most show evidence of interaction with three distinct carbon isotope reservoirs. These reservoirs are tentatively identified as (1) soil CO2 gas equilibrated under open system conditions with groundwater in the recharge zone [δ13CDIC ≈ -18‰, 14C > 100 pmc], (2) dissolved carbon equilibrated with atmospheric CO2 gas [δ13CDIC ≈ +1‰, 14C > 100 pmc], and (3) dissolved carbon derived from volcanic CO2 gas emissions [δ13CDIC≈0‰, 14C=0 pmc]. Many regional waters show a decrease in 14C abundance with increasing δ13C values, a pattern indicative of interaction with dead carbon originating from volcanic CO2 gas. Several lines of evidence suggest that actual groundwater residence times are too short (⩽ 200 years) to apply radiocarbon dating corrections. In particular, water temperatures measured at springs show that deep groundwater circulation does not occur, which implies an insufficient aquifer volume to account for both the high discharge rates and long residence times suggested by 14C apparent ages. The large springs also exhibit rapid decreases in flow during periods of drought that suggests a high level of aquifer interconnectivity to the recharge area. The estimated amount of volcanic CO2 dissolved in surface and groundwater originating from the Lassen highlands is consistent with the conversion of approximately 10% of the geothermal CO2 flux into dissolved inorganic carbon.

Monitoring a pilot CO2 injection experiment in a shallow aquifer using 3D cross-well electrical resistance tomography

NASA Astrophysics Data System (ADS)

Yang, X.; Lassen, R. N.; Looms, M. C.; Jensen, K. H.

2014-12-01

Three dimensional electrical resistance tomography (ERT) was used to monitor a pilot CO2 injection experiment at Vrøgum, Denmark. The purpose was to evaluate the effectiveness of the ERT method for monitoring the two opposing effects from gas-phase and dissolved CO2 in a shallow unconfined siliciclastic aquifer. Dissolved CO2 increases water electrical conductivity (EC) while gas phase CO2 reduce EC. We injected 45kg of CO2 into a shallow aquifer for 48 hours. ERT data were collected for 50 hours following CO2 injection. Four ERT monitoring boreholes were installed on a 5m by 5m square grid and each borehole had 24 electrodes at 0.5 m electrode spacing at depths from 1.5 m to 13 m. ERT data were inverted using a difference inversion algorithm for bulk EC. 3D ERT successfully detected the CO2 plume distribution and growth in the shallow aquifer. We found that the changes of bulk EC were dominantly positive following CO2 injection, indicating that the effect of dissolved CO2 overwhelmed that of gas phase CO2. The pre-injection baseline resistivity model clearly showed a three-layer structure of the site. The electrically more conductive glacial sand layer in the northeast region are likely more permeable than the overburden and underburden and CO2 plumes were actually confined in this layer. Temporal bulk EC increase from ERT agreed well with water EC and cross-borehole ground penetrating radar data. ERT monitoring offers a competitive advantage over water sampling and GPR methods because it provides 3D high-resolution temporal tomographic images of CO2 distribution and it can also be automated for unattended operation. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC. LLNL IM release#: LLNL-PROC-657944.

Dissolution actuated sample container

DOEpatents

Nance, Thomas A.; McCoy, Frank T.

2013-03-26

A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

An effective device for gas-liquid oxygen removal in enclosed microalgae culture.

PubMed

Su, Zhenfeng; Kang, Ruijuan; Shi, Shaoyuan; Cong, Wei; Cai, Zhaoling

2010-01-01

A high-performance gas-liquid transmission device (HPTD) was described in this paper. To investigate the HPTD mass transfer characteristics, the overall volumetric mass transfer coefficients, K(A)(La,CO(2)) for the absorption of gaseous CO(2) and K(A)(La,O(2)) for the desorption of dissolved O(2) were determined, respectively, by titration and dissolved oxygen electrode. The mass transfer capability of carbon dioxide was compared with that of dissolved oxygen in the device, and the operating conditions were optimized to suit for the large-scale enclosed micro-algae cultivation. Based on the effectiveness evaluation of the HPTD applied in one enclosed flat plate Spirulina culture system, it was confirmed that the HPTD can satisfy the demand of the enclosed system for carbon supplement and excessive oxygen removal.

Predicting the Fate and Effects of Resuspended Metal Contaminated Sediments

DTIC Science & Technology

2015-12-23

force on the sediment. Over the course of the experiment, dissolved and particulate metal concentrations, dissolved oxygen , temperature , turbidity, pH...dissolved oxygen , and temperature . A 16-hour multiple resuspension was also implemented in the SeFEC, intended to replicate intermittent ship traffic...was sampled at the end of hours 4, 8, 12, and 16. Samples were analyzed for: dissolved metals, pH, dissolved oxygen , and temperature (three

Seasonal and Latitudinal Variations in Dissolved Methane from 42 Lakes along a North-South Transect in Alaska

NASA Astrophysics Data System (ADS)

Sepulveda-Jauregui, A.; Walter Anthony, K. M.; Martinez-Cruz, K. C.; Anthony, P.; Thalasso, F.

2013-12-01

Armando Sepulveda-Jauregui,* Katey M. Walter Anthony,* Karla Martinez-Cruz,* ** Peter Anthony,* and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Northern lakes are important reservoirs and sources to the atmosphere of methane (CH4), a potent greenhouse gas. It is estimated that northern lakes (> 55 °N) contribute about 20% of the total global lake methane emissions, and that emissions from these lakes will increase with climate warming. Temperature rise enhances methane production directly by providing the kinetic energy to methanogenesis, and indirectly by supplying organic matter from thawing permafrost. Warmer lakes also store less methane since methane's solubility is inversely related to temperature. Alaskan lakes are located in three well-differentiated permafrost classes: yedoma permafrost with high labile carbon stocks, non-yedoma permafrost with lower carbon stocks, and areas without permafrost, also with generally lower carbon stocks. We sampled dissolved methane from 42 Alaskan lakes located in these permafrost cover classes along a north-south Alaska transect from Prudhoe Bay to the Kenai Peninsula during open-water conditions in summer 2011. We sampled 26 of these lakes in April, toward the end of the winter ice-covered period. Our results indicated that the largest dissolved methane concentrations occurred in interior Alaska thermokarst lakes formed in yedoma-type permafrost during winter and summer, with maximal concentrations of 17.19 and 12.76 mg L-1 respectively. In these lakes, emission of dissolved gases as diffusion during summer and storage release in spring were 18.4% and 17.4% of the annual emission budget, while ebullition (64.2 %) comprised the rest. Dissolved oxygen was inversely correlated with dissolved methane concentrations in both seasons; the absence of O2 enhances methane production, while high concentration of O2 could favor methane oxidation. These relationships suggest that permafrost type, and specifically the availability of permafrost organic matter, influences methane cycling in Alaskan lakes.

Relationship of Shallow Groundwater Quality to Hydraulic Fracturing Activities in Antrim and Kalkaska Counties, MI

NASA Astrophysics Data System (ADS)

Stefansky, J. N.; Robertson, W. M.; Chappaz, A.; Babos, H.; Israel, S.; Groskreutz, L. M.

2015-12-01

Hydraulic fracturing (fracking) of oil and natural gas (O&G) wells is a widely applied technology that can increase yields from tight geologic formations. However, it is unclear how fracking may impact shallow groundwater; previous research into its effects has produced conflicting results. Much of the worry over potential impacts to water quality arises from concerns about the produced water. The water produced from O&G formations is often salty, contains toxic dissolved elements, and can be radioactive. If fracking activities cause or increase connectivity between O&G formations and overlying groundwater, there may be risks to aquifers. As one part of a groundwater quality study in Antrim and Kalkaska Counties, MI, samples were collected from the unconfined glacial aquifer (3-300 m thick) and produced water from the underlying Antrim formation, a shallow (180-670 m deep) natural gas producing black shale. Groundwater samples were collected between 200 to 10,000 m distance from producing Antrim gas wells and from a range of screened intervals (15-95 m). Samples were analyzed for major constituents (e.g., Br, Cl), pH, conductivity, and dissolved oxygen (DO). The specific conductance of groundwater samples ranged from 230-1020 μS/cm; DO ranged from 0.4-100% saturation. Preliminary results show a slight inverse correlation between specific conductance and proximity to producing Antrim wells. The observed range of DO saturation in glacial aquifer groundwater appears to be related to both screened depth of the water wells and proximity to Antrim wells. During sampling, some well owners expressed concerns about the effects of fracking on groundwater quality and reported odd smells and tastes in their water after O&G drilling occurred near their homes. The results of this study and reported observations provide evidence to suggest a potential hydrogeological connection between the Antrim formation and the overlying glacial aquifer in some locations; it also raises questions about water quality in Antrim and Kalkaska counties. Further investigation is needed to address questions raised in this study. As the controversy surrounding fracking is growing and the application of this technology spreads worldwide, it is important for the questions about fracking and groundwater quality to be well addressed.

Investigation of air solubility in jet A fuel at high pressures

NASA Technical Reports Server (NTRS)

Rupprecht, S. D.; Faeth, G. M.

1981-01-01

The solubility and density properties of saturated mixtures of fuels and gases were measured. The fuels consisted of Jet A and dodecane, the gases were air and nitrogen. The test range included pressures of 1.03 to 10.34 MPa and temperatures of 298 to 373 K. The results were correlated successfully, using the Soave equation of state. Over this test range, dissolved gas concentrations were roughly proportional to pressure and increased slightly with increasing temperature. Mixture density was relatively independent of dissolved gas concentration.

Total dissolved gas and water temperature in the lower Columbia River, Oregon and Washington, 2007: Quality-assurance data and comparison to water-quality standards

USGS Publications Warehouse

Tanner, Dwight Q.; Bragg, Heather M.; Johnston, Matthew W.

2007-01-01

For the eight monitoring sites in water year 2007, an average of 99.5% of the total-dissolved-gas data were received in real time by the USGS satellite downlink and were within 1% saturation of the expected value on the basis of calibration data, replicate quality-control measurements in the river, and comparison to ambient river conditions at adjacent sites. Data received from the sites ranged from 97.9% to 100.0% complete.

Dissolved methane in New York groundwater, 1999-2011

USGS Publications Warehouse

Kappel, William M.; Nystrom, Elizabeth A.

2012-01-01

New York State is underlain by numerous bedrock formations of Cambrian to Devonian age that produce natural gas and to a lesser extent oil. The first commercial gas well in the United States was dug in the early 1820s in Fredonia, south of Buffalo, New York, and produced methane from Devonian-age black shale. Methane naturally discharges to the land surface at some locations in New York. At Chestnut Ridge County Park in Erie County, just south of Buffalo, N.Y., several surface seeps of natural gas occur from Devonian black shale, including one behind a waterfall. Methane occurs locally in the groundwater of New York; as a result, it may be present in drinking-water wells, in the water produced from those wells, and in the associated water-supply systems (Eltschlager and others, 2001). The natural gas in low-permeability bedrock formations has not been accessible by traditional extraction techniques, which have been used to tap more permeable sandstone and carbonate bedrock reservoirs. However, newly developed techniques involving horizontal drilling and high-volume hydraulic fracturing have made it possible to extract previously inaccessible natural gas from low-permeability bedrock such as the Marcellus and Utica Shales. The use of hydraulic fracturing to release natural gas from these shale formations has raised concerns with water-well owners and water-resource managers across the Marcellus and Utica Shale region (West Virginia, Pennsylvania, New York and parts of several other adjoining States). Molofsky and others (2011) documented the widespread natural occurrence of methane in drinking-water wells in Susquehanna County, Pennsylvania. In the same county, Osborn and others (2011) identified elevated methane concentrations in selected drinking-water wells in the vicinity of Marcellus gas-development activities, although pre-development samples were not available for comparison. In order to manage water resources in areas of gas-well drilling and hydraulic fracturing in New York, the natural occurrence of methane in the State's aquifers needs to be documented. This brief report presents a compilation of data on dissolved methane concentrations in the groundwater of New York available from the U.S. Geological Survey (USGS) National Water Information System (NWIS) (http://waterdata.usgs.gov/nwis).

Attractive forces between hydrophobic solid surfaces measured by AFM on the first approach in salt solutions and in the presence of dissolved gases.

PubMed

Azadi, Mehdi; Nguyen, Anh V; Yakubov, Gleb E

2015-02-17

Interfacial gas enrichment of dissolved gases (IGE) has been shown to cover hydrophobic solid surfaces in water. The atomic force microscopy (AFM) data has recently been supported by molecular dynamics simulation. It was demonstrated that IGE is responsible for the unexpected stability and large contact angle of gaseous nanobubbles at the hydrophobic solid-water interface. Here we provide further evidence of the significant effect of IGE on an attractive force between hydrophobic solid surfaces in water. The force in the presence of dissolved gas, i.e., in aerated and nonaerated NaCl solutions (up to 4 M), was measured by the AFM colloidal probe technique. The effect of nanobubble bridging on the attractive force was minimized or eliminated by measuring forces on the first approach of the AFM probe toward the flat hydrophobic surface and by using high salt concentrations to reduce gas solubility. Our results confirm the presence of three types of forces, two of which are long-range attractive forces of capillary bridging origin as caused by either surface nanobubbles or gap-induced cavitation. The third type is a short-range attractive force observed in the absence of interfacial nanobubbles that is attributed to the IGE in the form of a dense gas layer (DGL) at hydrophobic surfaces. Such a force was found to increase with increasing gas saturation and to decrease with decreasing gas solubility.

Sources of groundwater based on Helium analyses in and near the freshwater/saline-water transition zone of the San Antonio segment of the Edwards Aquifer, South-Central Texas, 2002-03

USGS Publications Warehouse

Hunt, Andrew G.; Lambert, Rebecca B.; Fahlquist, Lynne

2010-01-01

This report evaluates dissolved noble gas data, specifically helium-3 and helium-4, collected by the U.S. Geological Survey, in cooperation with the San Antonio Water System, during 2002-03. Helium analyses are used to provide insight into the sources of groundwater in the freshwater/saline-water transition zone of the San Antonio segment of the Edwards aquifer. Sixty-nine dissolved gas samples were collected from 19 monitoring wells (categorized as fresh, transitional, or saline on the basis of dissolved solids concentration in samples from the wells or from fluid-profile logging of the boreholes) arranged in five transects, with one exception, across the freshwater/saline-water interface (the 1,000-milligrams-per-liter dissolved solids concentration threshold) of the Edwards aquifer. The concentration of helium-4 (the dominant isotope in atmospheric and terrigenic helium) in samples ranged from 63 microcubic centimeters per kilogram at standard temperature (20 degrees Celsius) and pressure (1 atmosphere) in a well in the East Uvalde transect to 160,587 microcubic centimeters per kilogram at standard temperature and pressure in a well in the Kyle transect. Helium-4 concentrations in the 10 saline wells generally increase from the western transects to the eastern transects. Increasing helium-4 concentrations from southwest to northeast in the transition zone, indicating increasing residence time of groundwater from southwest to northeast, is consistent with the longstanding conceptualization of the Edwards aquifer in which water recharges in the southwest, flows generally northeasterly (including in the transition zone, although more slowly than in the fresh-water zone), and discharges at major springs in the northeast. Excess helium-4 was greater than 1,000 percent for 60 of the 69 samples, indicating that terrigenic helium is largely present and that most of the excess helium-4 comes from sources other than the atmosphere. The helium data of this report cannot be used to identify sources of groundwater in and near the transition zone of the Edwards aquifer in terms of specific geologic (stratigraphic) units or hydrogeologic units (aquifers or confining units). However, the data indicate that the source or sources of the helium, and thus the water in which the helium is dissolved, in the transition zone are mostly terrigenic in origin rather than atmospheric. Whether most helium in and near the transition zone of the Edwards aquifer originated either in rocks outside the transition zone and at depth or in the adjacent Trinity aquifer is uncertain; but most of the helium in the transition zone had to enter the transition zone from the Trinity aquifer because the Trinity aquifer is the hydrogeologic unit immediately beneath and laterally adjacent to the transition zone of the Edwards aquifer. Thus the helium data support a hypothesis of sufficient hydraulic connection between the Trinity and Edwards aquifers to allow movement of water from the Trinity aquifer to the transition zone of the Edwards aquifer.

Vesicles in Apollo 15 Green Glasses: The Nature of Ancient Lunar Gases

NASA Technical Reports Server (NTRS)

Thomas-Keprta, K. L.; Clemett, S. J.; Berger, E. L.; Rahman, Z.; McKay, D. S.; Gibson, E. K.; Wentworth, S. J.

2014-01-01

Detailed studies of Apollo 15 green glass and related beads have shown they were formed in gas-rich fire fountains.. As the magmatic fluid became super-saturated in volatile gas, bubbles or vesicles formed within the magma. These exsolved gases became trapped within vesicles as the glasses were ejected from the fire-fountain and subsequently quenched. One of the keys to understanding formation processes on the ancient moon includes determining the composition of volatile species and elements, including metals, dissolved in magmatic gases. Here we report the nature of mineral phases spatially associated with vesicles in a green glass bead from Apollo sample 15411,42. The phases reflect the composition of the cooling/degassing magmatic vapors and fluids present at the time of bead formation approx, 3 Ga ago

Effect of natural gas exsolution on specific storage in a confined aquifer undergoing water level decline.

PubMed

Yager, R M; Fountain, J C

2001-01-01

The specific storage of a porous medium, a function of the compressibility of the aquifer material and the fluid within it, is essentially constant under normal hydrologic conditions. Gases dissolved in ground water can increase the effective specific storage of a confined aquifer, however, during water level declines. This causes a reduction in pore pressure that lowers the gas solubility and results in exsolution. The exsolved gas then displaces water from storage, and the specific storage increases because gas compressibility is typically much greater than that of water or aquifer material. This work describes the effective specific storage of a confined aquifer exsolving dissolved gas as a function of hydraulic head and the dimensionless Henry's law constant for the gas. This relation is applied in a transient simulation of ground water discharge from a confined aquifer system to a collapsed salt mine in the Genesee Valley in western New York. Results indicate that exsolution of gas significantly increased the effective specific storage in the aquifer system, thereby decreasing the water level drawdown.

Effect of natural gas exsolution on specific storage in a confined aquifer undergoing water level decline

USGS Publications Warehouse

Yager, R.M.; Fountain, J.C.

2001-01-01

The specific storage of a porous medium, a function of the compressibility of the aquifer material and the fluid within it, is essentially constant under normal hydrologic conditions. Gases dissolved in ground water can increase the effective specific storage of a confined aquifer, however, during water level declines. This causes a reduction in pore pressure that lowers the gas solubility and results in exsolution. The exsolved gas then displaces water from storage, and the specific storage increases because gas compressibility is typically much greater than that of water or aquifer material. This work describes the effective specific storage of a confined aquifer exsolving dissolved gas as a function of hydraulic head and the dimensionless Henry's law constant for the gas. This relation is applied in a transient simulation of ground water discharge from a confined aquifer system to a collapsed salt mine in the Genesee Valley in western New York. Results indicate that exsolution of gas significantly increased the effective specific storage in the aquifer system, thereby decreasing the water level drawdown.

Using noble gases measured in spring discharge to trace hydrothermal processes in the Norris Geyser Basin, Yellowstone National Park, U.S.A.

USGS Publications Warehouse

Gardner, W.P.; Susong, D.D.; Solomon, D.K.; Heasler, H.P.

2010-01-01

Dissolved noble gas concentrations in springs are used to investigate boiling of hydrothermal water and mixing of hydrothermal and shallow cool water in the Norris Geyser Basin area. Noble gas concentrations in water are modeled for single stage and continuous steam removal. Limitations on boiling using noble gas concentrations are then used to estimate the isotopic effect of boiling on hydrothermal water, allowing the isotopic composition of the parent hydrothermal water to be determined from that measured in spring. In neutral chloride springs of the Norris Geyser Basin, steam loss since the last addition of noble gas charged water is less than 30% of the total hydrothermal discharge, which results in an isotopic shift due to boiling of ?? 2.5% ??D. Noble gas concentrations in water rapidly and predictably change in dual phase systems, making them invaluable tracers of gas-liquid interaction in hydrothermal systems. By combining traditional tracers of hydrothermal flow such as deuterium with dissolved noble gas measurements, more complex hydrothermal processes can be interpreted. ?? 2010 Elsevier B.V.

Assessment of diel chemical and isotopic techniques to investigate biogeochemical cycles in the upper Klamath River, Oregon, USA

USGS Publications Warehouse

Poulson, S.R.; Sullivan, A.B.

2009-01-01

The upper Klamath River experiences a cyanobacterial algal bloom and poor water quality during the summer. Diel chemical and isotopic techniques have been employed in order to investigate the rates of biogeochemical processes. Four diel measurements of field parameters (temperature, pH, dissolved oxygen concentrations, and alkalinity) and stable isotope compositions (dissolved oxygen-??18O and dissolved inorganic carbon-??13C) have been performed between June 2007 and August 2008. Significant diel variations of pH, dissolved oxygen (DO) concentration, and DO-??18O were observed, due to varying rates of primary productivity vs. respiration vs. gas exchange with air. Diel cycles are generally similar to those previously observed in river systems, although there are also differences compared to previous studies. In large part, these different diel signatures are the result of the low turbulence of the upper Klamath River. Observed changes in the diel signatures vs. sampling date reflect the evolution of the status of the algal bloom over the course of the summer. Results indicate the potential utility of applying diel chemical and stable isotope techniques to investigate the rates of biogeochemical cycles in slow-moving rivers, lakes, and reservoirs, but also illustrate the increased complexity of stable isotope dynamics in these low-turbulence systems compared to well-mixed aquatic systems. ?? 2009 Elsevier B.V.

Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation

USGS Publications Warehouse

Conaway, Christopher; Thomas, Randal B.; Saad, Nabil; Thordsen, James J.; Kharaka, Yousif K.

2015-01-01

This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ13C of dissolved organic carbon (δ13C-DOC) in natural water samples. Low-chloride matrix (<5 g Cl/L) DOC solutions were analysed with as little as 2.5 mg C/L in a 9 mL aliquot with a precision of 0.5 ‰. In high-chloride matrix (10–100 g Cl/L) DOC solutions, bias towards lighter δ13C-DOC was observed because of incomplete oxidation despite using high-concentration oxidant, extended reaction time, or post-wet chemical oxidation gas-phase combustion. However, through a combination of dilution, chloride removal, and increasing the oxidant:sample ratio, high-salinity samples with sufficient DOC (>22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

Dynamics of hydrophobic organic contaminants in the Baltic proper pelagial

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

Axelman, J.; Broman, D.; Naef, C.

Hydrophobic organic contaminants occur in different forms in natural water. Apart from being truly dissolved in water they partition into dissolved organic carbon (DOC) and particles of different sizes including pelagic bacteria, phytoplankton and zooplankton. The distribution between the different forms is dependent on carbon turnover rates in and transport between the different compartments and on the physical and chemical properties of the compound in focus. The water phase, the DOC-phase and two particle size fractions, 0.2--2pm and 2--20 pm representing the base of the pelagic food web, were analyzed for their content of PCBs and PAHs during summer andmore » winter conditions in the open sea in the Baltic proper. New methods for separating truly dissolved from DOC-bound compounds have been developed using a high capacity perfusion adsorbent and large scale gas sparging. The small particle size fraction was sampled using high volume tangential flow filtration. The possibility to separate between these four different compartments has given a more detailed picture of the short term dynamics of hydrophobic organic compounds in the important base of the pelagial food web.« less

Mid-Infrared Spectroscopic Method for the Identification and Quantification of Dissolved Oil Components in Marine Environments.

PubMed

Stach, Robert; Pejcic, Bobby; Crooke, Emma; Myers, Matthew; Mizaikoff, Boris

2015-12-15

The use of mid-infrared sensors based on conventional spectroscopic equipment for oil spill monitoring and fingerprinting in aqueous systems has to date been mainly confined to laboratory environments. This paper presents a portable-based mid-infrared attenuated total reflectance (MIR-ATR) sensor system that was used to quantify a number of environmentally relevant hydrocarbon contaminants in marine water. The sensor comprises a polymer-coated diamond waveguide in combination with a room-temperature operated pyroelectric detector, and the analytical performance was optimized by evaluating the influence of polymer composition, polymer film thickness, and solution flow rate on the sensor response. Uncertainties regarding the analytical performance and instrument specifications for dissolved oil detection were investigated using real-world seawater matrices. The reliability of the sensor was tested by exposition to known volumes of different oils; crude oil and diesel samples were equilibrated with seawater and then analyzed using the developed MIR-ATR sensor system. For validation, gas chromatographic measurements were performed revealing that the MIR-ATR sensor is a promising on-site monitoring tool for determining the concentration of a range of dissolved oil components in seawater at ppb to ppm levels.

Quality-assurance results for routine water analyses in U.S. Geological Survey laboratories, water year 1998

USGS Publications Warehouse

Ludtke, Amy S.; Woodworth, Mark T.; Marsh, Philip S.

2000-01-01

The U.S. Geological Survey operates a quality-assurance program based on the analyses of reference samples for two laboratories: the National Water Quality Laboratory and the Quality of Water Service Unit. Reference samples that contain selected inorganic, nutrient, and low-level constituents are prepared and submitted to the laboratory as disguised routine samples. The program goal is to estimate precision and bias for as many analytical methods offered by the participating laboratories as possible. Blind reference samples typically are submitted at a rate of 2 to 5 percent of the annual environmental-sample load for each constituent. The samples are distributed to the laboratories throughout the year. The reference samples are subject to the identical laboratory handling, processing, and analytical procedures as those applied to environmental samples and, therefore, have been used as an independent source to verify bias and precision of laboratory analytical methods and ambient water-quality measurements. The results are stored permanently in the National Water Information System and the Blind Sample Project's data base. During water year 1998, 95 analytical procedures were evaluated at the National Water Quality Laboratory and 63 analytical procedures were evaluated at the Quality of Water Service Unit. An overall evaluation of the inorganic and low-level constituent data for water year 1998 indicated 77 of 78 analytical procedures at the National Water Quality Laboratory met the criteria for precision. Silver (dissolved, inductively coupled plasma-mass spectrometry) was determined to be imprecise. Five of 78 analytical procedures showed bias throughout the range of reference samples: chromium (dissolved, inductively coupled plasma-atomic emission spectrometry), dissolved solids (dissolved, gravimetric), lithium (dissolved, inductively coupled plasma-atomic emission spectrometry), silver (dissolved, inductively coupled plasma-mass spectrometry), and zinc (dissolved, inductively coupled plasma-mass spectrometry). At the National Water Quality Laboratory during water year 1998, lack of precision was indicated for 2 of 17 nutrient procedures: ammonia as nitrogen (dissolved, colorimetric) and orthophosphate as phosphorus (dissolved, colorimetric). Bias was indicated throughout the reference sample range for ammonia as nitrogen (dissolved, colorimetric, low level) and nitrate plus nitrite as nitrogen (dissolved, colorimetric, low level). All analytical procedures tested at the Quality of Water Service Unit during water year 1998 met the criteria for precision. One of the 63 analytical procedures indicated a bias throughout the range of reference samples: aluminum (whole-water recoverable, inductively coupled plasma-atomic emission spectrometry, trace).

ELEVATED DISSOLVED SULFIDES IN SURFICIAL SEDIMENTS OF YAQUINA BAY ESTUARY, OREGON

EPA Science Inventory

Dissolved sulfide concentrations were measured in porewater of surficial sediments collected from two exposed intertidal sites in Yaquina Bay, Oregon. Idaho Pt. (IP) is an area where drift green macroalgae is known to accumulate, and the odor of hydrogen sulfide gas (H2S) on th...

ANALYSIS OF DISSOLVED METHANE, ETHANE, AND ETHYLENE IN GROUND WATER BY A STANDARD GAS CHROMATOGRAPHIC TECHNIQUE

EPA Science Inventory

The measurement of dissolved gases such as methane, ethane, and ethylene in ground water is important in determining whether intrinsic bioremediation is occurring in a fuel- or solvent-contaminated aquifer. A simple procedure is described for the collection and subsequent analys...

A Novel Method for Analysis of Dissolved Inorganic Carbon Concentration and δ13C by Cavity Ring-Down Spectroscopy

NASA Astrophysics Data System (ADS)

Smith, E.; Gonneea, M. E.; Boze, L. G.; Casso, M.; Pohlman, J.

2017-12-01

Dissolved inorganic carbon (DIC) is the largest pool of carbon in the oceans and is where about half of anthropogenic carbon dioxide (CO2) emissions are being sequestered. Determining the concentration and stable carbon isotopic content (δ13C) of DIC allows us to delineate carbon sources that contribute to marine DIC. A simple and reliable method for measuring DIC concentration and δ13C can be used to apportion contributions from external sources and identify effects from biogeochemical reactions that contribute or remove DIC. The U.S. Geological Survey has developed a discrete sample analysis module (DSAM) that interfaces to a Picarro G-2201i cavity ring-down spectrometer (CRDS, Picarro Inc.) to analyze CO2 and methane concentrations and δ13C from discrete gas samples. In this study, we adapted the USGS DSAM-CRDS analysis system to include an AutoMate prep device (Automate FX, Inc.) for analysis of DIC concentration and δ13C from aqueous samples. The Automate prep device was modified to deliver CO2 extracted from DIC to the DSAM, which conditions and transfers the gas to the CRDS. LabVIEW software (National Instruments) triggers the Automate Prep device, controls the DSAM and collects data from the CRDS. CO2 mass concentration data are obtained by numerical integration of the CO2 volumetric concentrations output by the CRDS and subsequent comparison to standard materials. CO2 carbon isotope values from the CRDS (iCO2) are converted to δ13C values using a slope and offset correction calibration procedure. The system design and operation was optimized using sodium bicarbonate (NaHCO3) standards and a certified reference material. Surface water and pore water samples collected from Sage Lot Pond, a salt marsh in Cape Cod MA, have been analyzed for concentration by coulometry and δ13C by isotope ratio mass spectrometry and will be used to validate the DIC-DSAM-CRDS method for field applications.

Equilibrator-based measurements of dissolved nitrous oxide in the surface ocean using an integrated cavity output laser absorption spectrometer

NASA Astrophysics Data System (ADS)

Grefe, I.; Kaiser, J.

2014-06-01

Dissolved nitrous oxide (N2O) concentrations are usually determined by gas chromatography (GC). Here we present laboratory tests and initial field measurements using a novel setup comprising a commercially available laser-based analyser for N2O, carbon monoxide and water vapour coupled to a glass-bed equilibrator. This approach is less labour-intensive and provides higher temporal and spatial resolution than the conventional GC technique. The standard deviation of continuous equilibrator or atmospheric air measurements was 0.2 nmol mol-1 (averaged over 5 min). The short-term repeatability for reference gas measurements within 1 h of each other was 0.2 nmol mol-1 or better. Another indicator of the long-term stability of the analyser is the standard deviation of the calibrated N2O mole fraction in marine air, which was between 0.5 and 0.7 nmol mol-1. The equilibrator measurements were compared with purge-and-trap gas chromatography-mass spectrometry (GC-MS) analyses of N2O concentrations in discrete samples from the Southern Ocean and showed agreement to within the 2% measurement uncertainty of the GC-MS method. The equilibrator response time to concentration changes in water was from 142 to 203 s, depending on the headspace flow rate. The system was tested at sea during a north-to-south transect of the Atlantic Ocean. While the subtropical gyres were slightly undersaturated, the equatorial region was a source of nitrous oxide to the atmosphere, confirming previous findings (Forster et al., 2009). The ability to measure at high temporal and spatial resolution revealed submesoscale variability in dissolved N2O concentrations. Mean sea-to-air fluxes in the tropical and subtropical Atlantic ranged between -1.6 and 0.11 μmol m-2 d-1 and confirm that the subtropical Atlantic is not an important source region for N2O to the atmosphere, compared to global average fluxes of 0.6-2.4 μmol m-2 d-1. The system can be easily modified for autonomous operation on voluntary observing ships (VOS). Future work should include an interlaboratory comparison exercise with other methods of dissolved N2O analyses.

Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

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

Jolley, R.L.; Begovich, J.M.; Brashear, H.R.

1983-12-01

Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be /sup 133/Xe, and /sup 198/Au (on carbonized resin or as an aqueous colloidal suspension) will be used as themore » slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing.« less

Quantifying the Movement and Dissolution of Fugitive Methane in Shallow Aquifers: Visualization Experiments

NASA Astrophysics Data System (ADS)

Van De Ven, C. J. C.; Mumford, K. G.

2016-12-01

The environmental impact and potential human health implications, specifically from the contamination of groundwater sources, has sparked controversy around shale gas extraction in North America. It is clear that understanding the effects of hydraulic fracturing on shallow fresh water aquifers is of great importance, including the threat of stray gas (also referred to as fugitive methane) on groundwater quality. Faulty wells provide a preferential pathway for free gas phase (mostly methane) to migrate from deeper gas-bearing formations of natural gas to shallow aquifers, followed by its dissolution into the surrounding groundwater. An increased understanding of the fate of fugitive methane in shallow aquifers is required to assess the potential risks associated with current and future operations, as well as to better link gas migration, dissolution and the deterioration of groundwater quality. In this study, a series of laboratory experiments were performed using carbon dioxide (CO2) gas as a surrogate for methane to improve our understanding of gas dissolution in groundwater systems. Using CO2, a novel laboratory technique was developed that allows the measurement of dissolved CO2 concentrations using image analysis alongside visualization of free gas mobilization. The technique is based on the acidification of water during CO2 dissolution, which causes a colour change in an indicator dye. The colour change is recorded using a visual light transmission technique, in which digital images are used to track dissolved concentrations at high spatial (1 mm) and temporal (5 s) resolutions in a two-dimensional (25 × 25 × 1 cm3) flow cell. The experiments were completed in both homogeneous sand packs and sand packs containing layered heterogeneities to investigate the dissolution of both gas fingers and gas pools. The results demonstrate the potential of this novel technique for investigating gas dissolution, and showed significant tailing of dissolved CO2 and persistence of other gas phase components. This technique will aid in the development of conceptual models to link fugitive methane to groundwater contamination and provide detailed data required for the validation of numerical models that account for gas-water mass transfer; both of which are required for the development of sound monitoring techniques.

Summary and evaluation of the quality of stormwater in Denver, Colorado, 2006-2010

USGS Publications Warehouse

Stevens, Michael R.; Slaughter, Cecil B.

2012-01-01

Stormwater in the Denver area was sampled by the U.S. Geological Survey, in cooperation with the Urban Drainage and Flood Control District, in a network of 5 monitoring stations - 3 on the South Platte River and 2 on streams tributary to the South Platte River, Sand Creek, and Toll Gate Creek beginning in January 2006 and continuing through December 2010. Stormwater samples were analyzed at the U.S. Geological Survey National Water Quality Laboratory during 2006-2010 for water-quality properties such as pH, specific conductance, hardness, and residue on evaporation at 105 degrees Celsius; for constituents such as major ions (calcium, magnesium), organic carbon and nutrients, including ammonia plus organic nitrogen, ammonia, dissolved nitrite plus nitrate, total phosphorus, and orthophosphate; and for metals, including total recoverable and dissolved phases of copper, lead, manganese, and zinc. Samples collected during selected storms were also analyzed for bacteriological indicators such as Escherichia coli and fecal coliform at the Metro Wastewater Reclamation Laboratory. About 200 stormwater samples collected during storms characterize the quality of storm runoff during 2006-2010. In general, the quality of stormwater (2006-2010) has improved for many water-quality constituents, many of which had lower values and concentrations than those in stormwater collected in 2002-2005. However, the physical basis, processes, and the role of dilution that account for these changes are complex and beyond the scope of this report. The water-quality sampling results indicate few exceptions to standards except for dissolved manganese, dissolved zinc, and Escherichia coli. Stormwater collected at the South Platte River below Union Avenue station had about 10 percent acute or chronic dissolved manganese exceedances in samples; samples collected at the South Platte River at Denver station had less than 5 percent acute or chronic dissolved manganese exceedances. In contrast, samples collected at Toll Gate Creek above 6th Avenue at Aurora station, Sand Creek at mouth near Commerce City station, and the South Platte River at Henderson station, each had about 30 to 50 percent exceedances of both acute and chronic dissolved manganese standards. Of the samples collected at Sand Creek at mouth near Commerce City, 1 sample exceeded the acute standard and 4 samples exceeded the chronic standard for dissolved zinc, but no samples collected from the other sites exceeded either standard for zinc. Almost all samples of stormwater analyzed for Escherichia coli exceeded Colorado numeric standards. A numerical standard for fecal coliform is no longer applicable as of 2004. Results from the 2002-2005 study indicated that the general quality of stormwater had improved during 2002-2005 compared to 1998-2001, having fewer exceedances of Colorado standards, and showing downward trends for many water-quality values and concentrations. These trends coincided with general downward or relatively similar mean streamflows for the 2002-2005 compared to 1998-2001, which indicates that dilution may be a smaller influence on values and concentrations than other factors. For this report, downward trends were indicated for many constituents at each station during 2006-2010 compared to 2002-2005. The trends for mean streamflow for 2006-2010 compared to 2002-2005 are upward at all sites except for the South Platte River at Henderson, indicating that dilution by larger flows could be a factor in the downward concentration trends. At the South Platte River below Union Avenue station, downward trends were indicated for hardness, dissolved ammonia, dissolved orthophosphate, and dissolved copper. Upward trends at South Platte River below Union Avenue were indicated for pH. At the South Platte River at Denver station, downward trends were indicated for total ammonia plus organic nitrogen, dissolved ammonia, dissolved nitrite plus nitrate, dissolved orthophosphate, total phosphorus, dissolved organic carbon, and dissolved lead, manganese, and zinc, and total recoverable zinc. An upward trend in properties and constituents at South Platte River at Denver was indicated for pH. At Toll Gate Creek above 6th Avenue at Aurora, downward trends were indicated for residue on evaporation, total ammonia plus organic nitrogen, dissolved ammonia, dissolved orthophosphate, total phosphorus, and total recoverable copper, lead, manganese, and zinc. Upward trends in properties and constituents at Toll Gate Creek above 6th Avenue at Aurora were indicated for pH, specific conductance, and dissolved nitrite plus nitrate. At Sand Creek at mouth near Commerce City, downward trends were indicated for hardness, dissolved calcium, total ammonia plus organic nitrogen, and dissolved ammonia, orthophosphate, manganese, and zinc. An upward trend in properties and constituents at Sand Creek at mouth near Commerce City was indicated for pH. Downward trends at South Platte River at Henderson were indicated for specific conductance, hardness, dissolved magnesium, residue on evaporation, total ammonia plus organic nitrogen, dissolved ammonia, dissolved nitrite plus nitrate, dissolved orthophosphate, total phosphorus, dissolved lead and manganese, and total recoverable copper, lead, manganese, and zinc.

DISSOLUTION OF PLUTONIUM METAL IN 8-10 M NITRIC ACID

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

Rudisill, T. S.; Pierce, R. A.

2012-07-02

The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, the development of a Pu metal dissolution flowsheet which utilizes concentrated (8-10 M) nitric acid (HNO{sub 3}) solutions containing potassium fluoride (KF) is required. Dissolution of Pu metal in concentrated HNO{sub 3} is desired to eliminate the need to adjust the solution acidity prior to purification by anion exchange. The preferred flowsheet would use 8-10 M HNO{sub 3}, 0.015-0.07 M KF, and 0.5-1.0 g/L Gd to dissolve the Pu upmore » to 6.75 g/L. An alternate flowsheet would use 8-10 M HNO{sub 3}, 0.05-0.2 M KF, and 1-2 g/L B to dissolve the Pu. The targeted average Pu metal dissolution rate is 20 mg/min-cm{sup 2}, which is sufficient to dissolve a “standard” 2250-g Pu metal button in 24 h. Plutonium metal dissolution rate measurements showed that if Gd is used as the nuclear poison, the optimum dissolution conditions occur in 10 M HNO{sub 3}, 0.04-0.05 M KF, and 0.5-1.0 g/L Gd at 112 to 116 °C (boiling). These conditions will result in an estimated Pu metal dissolution rate of ~11-15 mg/min-cm{sup 2} and will result in dissolution times of 36-48 h for standard buttons. The recommended minimum and maximum KF concentrations are 0.03 M and 0.07 M, respectively. The data also indicate that lower KF concentrations would yield dissolution rates for B comparable to those observed with Gd at the same HNO{sub 3} concentration and dissolution temperature. To confirm that the optimal conditions identified by the dissolution rate measurements can be used to dissolve Pu metal up to 6.75 g/L in the presence of representative concentrations of Fe and Gd or B, a series of experiments was performed to demonstrate the flowsheets. In three of the five experiments, the offgas generation rate during the dissolution was measured and samples were analyzed for hydrogen gas (H{sub 2}). The use of 10 M HNO{sub 3} containing 0.03-0.05 M KF, 0.5-1.0 g/L Gd, and 1.9 g/L Fe resulted in complete dissolution of the metal in 2.0-3.5 h. When B was used as the neutron poison, 10 M HNO{sub 3} solutions containing 0.05-0.1 M KF, 1.9 g/L Fe, and 1 g/L B resulted in complete dissolution of the metal in 0.75-2.0 h. Dissolution rates estimated using data from the flowsheet demonstrations agreed reasonably well with the measured rates; although, a discrepancy was observed in the Gd system. The presence of 1 g/L Gd or B in the dissolving solution had about the same effect on the dissolution rate. The predominant Pu valence in the dissolving solution was Pu(IV). The concentration of Pu(VI) was evaluated by UV-visible spectroscopy and was estimated to be significantly less than 1 wt %. The offgas generation rates and H{sub 2} concentrations measured in the offgas from experiments performed using 10 M HNO{sub 3} containing 0.05 M KF, 1.9 g/L Fe and either 1 g/L Gd or B were approximately the same. These data support the conclusion that the presence of either 1 g/L Gd or B had the same general effect on the dissolution rate. The calculated offgas generation during the dissolutions was 0.6 mol offgas/mol of Pu. The H{sub 2} concentration measured in the offgas from the dissolution using Gd as the neutron poison was approximately 0.5 vol %. In the B system, the H{sub 2} ranged from nominally 0.8 to 1 vol % which is about the same as measured in the Gd system within the uncertainty of the analysis. The offgas generation rate for the dissolution performed using 10 M HNO{sub 3} containing 0.03 M KF, 0.5 g/L Gd, and 1.9 g/L Fe was approximately a factor of two less than produced in the other dissolutions; however, the concentration of H{sub 2} measured in the offgas was higher. The adjusted concentration ranged from 2.7 to 8.8 vol % as the dissolution proceeded. Higher concentrations of H{sub 2} occur when the Pu dissolution proceeds by a metal/acid reaction rather than nitrate oxidation. The higher H{sub 2} concentration could be attributed to the reduced activity of the fluoride due to complexation with Pu as the dissolution progressed. Dissolution of Pu metal at 20 °C in 10 M HNO{sub 3} containing 0.05 M KF showed that the Pu metal dissolves slowly without any visible gas generation. As the Pu metal dissolves, it forms a more-dense Pu-bearing solution which sank to the bottom of the dissolution vessel. The dissolved Pu did not form a boundary layer around the sample and failed to distribute homogeneously due to minimal (thermally-induced) mixing. This indicates that in the H-Canyon dissolver insert, the Pu will diffuse out of the insert into the bulk dissolver solution where it will disperse. At 35 °C, the Pu metal dissolved without visible gas generation. However, due to thermal currents caused by maintaining the solution at 35 °C, the dissolved Pu distributed evenly throughout the dissolver solution. It did not form a boundary layer around the sample.« less

Analysis of minerals containing dissolved traces of the fluid phase components water and carbon dioxide

NASA Technical Reports Server (NTRS)

Freund, Friedemann

1991-01-01

Substantial progress has been made towards a better understanding of the dissolution of common gas/fluid phase components, notably H2O and CO2, in minerals. It has been shown that the dissolution mechanisms are significantly more complex than currently believed. By judiciously combining various solid state analytical techniques, convincing evidence was obtained that traces of dissolved gas/fluid phase components undergo, at least in part, a redox conversion by which they split into reduced H2 and and reduced C on one hand and oxidized oxygen, O(-), on the other. Analysis for 2 and C as well as for any organic molecules which may form during the process of co-segregation are still impeded by the omnipresent danger of extraneous contamination. However, the presence of O(-), an unusual oxidized form of oxygen, has been proven beyond a reasonable doubt. The presence of O(-) testifies to the fact that a redox reaction must have taken place in the solid state involving the dissolved traces of gas/fluid phase components. Detailed information on the techniques used and the results obtained are given.

Polychlorinated biphenyls in tree bark near a former manufacturing plant in Anniston, Alabama.

PubMed

Hermanson, Mark H; Johnson, Glenn W

2007-05-01

Tree bark samples were collected to identify the relative amounts and congener profiles of atmospheric polychlorinated biphenyls dissolved into bark lipids from the gas phase in Anniston, Alabama, USA, where PCBs were manufactured from the 1920s until 1971. The area is heavily contaminated with PCBs: At least 4550 metric tons (mt) of PCB and 14000 mt of PCB distillation residue, known as Montar, remain buried in two landfills near the plant site. A minimum of 20.5 mt of PCBs were emitted to the atmosphere by the plant between 1953 and 1971 based on emissions figures for 1970. Bark results show that total PCB concentrations range over more than three orders of magnitude from 171927 ng/g lipid near the plant/landfill area, dropping exponentially to 35 ng/g lipid at a distance of about 7 km. The exponential trend is highly correlated (r=-0.77) and significant (p<0.05). The most concentrated tree started growing after 1971 showing that atmospheric PCB concentrations remained high after PCB production ended. All PCB congener profiles show persistent congeners 31+28, 52, 66, 153, 138, and 180. Congener profiles from trees growing near the plant/landfill all have somewhat similar profiles but those growing during PCB production show high molecular mass compounds not usually found in the atmosphere and not found in younger trees, even in the most concentrated sample. We believe that high-temperature Montar disposal released high molecular mass PCBs into the gas phase which were dissolved into older tree bark lipids.

Geochemical Investigation of the Arbuckle-Simpson Aquifer, South-Central Oklahoma, 2004-06

USGS Publications Warehouse

Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.

2009-01-01

A geochemical reconnaissance investigation of the Arbuckle-Simpson aquifer in south-central Oklahoma was initiated in 2004 to characterize the ground-water quality at an aquifer scale, to describe the chemical evolution of ground water as it flows from recharge areas to discharge in wells and springs, and to determine the residence time of ground water in the aquifer. Thirty-six water samples were collected from 32 wells and springs distributed across the aquifer for chemical analysis of major ions, trace elements, isotopes of oxygen and hydrogen, dissolved gases, and age-dating tracers. In general, the waters from wells and springs in the Arbuckle-Simpson aquifer are chemically suitable for all regulated uses, such as public supplies. Dissolved solids concentrations are low, with a median of 347 milligrams per liter (mg/L). Two domestic wells produced water with nitrate concentrations that exceeded the U.S. Environmental Protection Agency's nitrate maximum contaminant level (MCL) of 10 mg/L. Samples from two wells in the confined part of the aquifer exceeded the secondary maximum contaminant level (SMCL) for chloride of 250 mg/L and the SMCL of 500 mg/L for dissolved solids. Water samples from these two wells are not representative of water samples from the other wells and springs completed in the unconfined part of the aquifer. No other water samples from the Arbuckle-Simpson geochemical reconnaissance exceeded MCLs or SMCLs, although not every chemical constituent for which the U.S. Environmental Protection Agency has established a MCL or SMCL was analyzed as part of the Arbuckle-Simpson geochemical investigation. The major ion chemistry of 34 of the 36 samples indicates the water is a calcium bicarbonate or calcium magnesium bicarbonate water type. Calcium bicarbonate water type is found in the western part of the aquifer, which is predominantly limestone. Calcium magnesium bicarbonate water is found in the eastern part of the aquifer, which is predominantly a dolomite. The major ion chemistry for these 34 samples is consistent with a set of water-rock interactions. Rainfall infiltrates the soil zone, where the host rock, limestone or dolomite, dissolves as a result of uptake of carbon dioxide gas. Some continued dissolution of dolomite and precipitation of calcite occur as the water flows through the saturated zone. The major ion chemistry of the two samples from wells completed in the confined part of the aquifer indicates the water is a sodium chloride type. Geochemical inverse modeling determined that mixing of calcite-saturated recharge water with brine and dissolving calcite, dolomite, and gypsum accounts for the water composition of these two samples. One of the two samples, collected at Vendome Well in Chickasaw National Recreation Area, had a mixing fraction of brine of about 1 percent. The brine component of the sample at Vendome Well is likely to account for the relatively large concentrations of many of the trace elements (potassium, fluoride, bromide, iodide, ammonia, arsenic, boron, lithium, selenium, and strontium) measured in the water sample. Carbon-14, helium-3/tritium, and chlorofluorocarbons were used to calculate ground-water ages, recharge temperatures, and mixtures of ground water in the Arbuckle-Simpson aquifer. Thirty four of 36 water samples recharged the aquifer after 1950, indicating that water is moving quickly from recharge areas to discharge at streams and springs. Two exceptions to this classification were noted in samples 6 and 15 (Vendome Well). Ground-water ages determined for these two samples by using carbon-14 are 34,000 years (site 6) and 10,500 years (site 15). Concentrations of dissolved argon, neon, and xenon in water samples were used to determine the temperature of the water when it recharged the aquifer. The mean annual air temperature at Ada, Oklahoma, is 16 degrees Celsius (C) and the median temperature of the 30 reconnaissance water samples was 18.1 C. The av

Description of landscape features, summary of existing hydrologic data, and identification of data gaps for the Osage Nation, northeastern Oklahoma, 1890-2012

USGS Publications Warehouse

Andrews, William J.; Smith, S. Jerrod

2014-01-01

The Osage Nation of northeastern Oklahoma, conterminous with Osage County, is characterized by gently rolling uplands and incised stream valleys that have downcut into underlying sedimentary rock units of Pennsylvanian through Permian age. Cattle ranching and petroleum and natural-gas extraction are the principal land uses in this rural area. Freshwater resources in the Osage Nation include water flowing in the Arkansas River and several smaller streams, water stored in several lakes, and groundwater contained in unconsolidated alluvial aquifers and bedrock aquifers. The Vamoosa-Ada aquifer is the primary source of fresh groundwater in this area. Fresh groundwater is underlain by saline groundwater in aquifers underlying the Osage Nation. Because of the potential for future population increases, demands for water from neighboring areas such as the Tulsa metropolitan area, and expansion of petroleum and natural-gas extraction on water resources of this area, the U.S. Geological Survey, in cooperation with the Osage Nation, summarized existing hydrologic data and identified data gaps to provide information for planning of future development of water resources in the Osage Nation. Streamflows in the Osage Nation are substantially affected by precipitation. During the relatively wet periods from the 1970s to 2000, the annual streamflows in the Osage Nation increased by as much as a factor of 2 relative to preceding decades, with subsequent decreases in streamflow of as much as 50 percent being recorded during intermittent drier years of the early 2000s. This report summarizes hydrologic data from 3 surface-water sites and 91 wells distributed across the Osage Nation. Data collected at those sites indicate that surface water in the Osage Nation generally has sufficient dissolved oxygen for survival of both coldwater and warmwater aquatic biota. Total dissolved solids concentration exceeded the secondary drinking-water standard of 500 milligrams per liter (mg/L) in up to 75 percent of the surface-water samples, indicating limited availability of potable water at some sites. Some surface-water samples collected in the Osage Nation contained dissolved chloride concentrations exceeding the secondary drinking-water standard of 250 mg/L, with greater chloride concentrations in selected basins appearing to be associated with greater densities of petroleum well locations. Several lakes sampled in the Osage Nation from 2011–12 contained sufficient chlorophyll-a concentrations to be ranked as mesotrophic to eutrophic, indicating impairment by nutrients. Relatively large dissolved phosphorus concentrations in many surface-water samples, compared to water-quality standards, indicate that eutrophication can occur in local streams and lakes. The amount of fresh groundwater stored in alluvial aquifers and the Vamoosa-Ada bedrock aquifer is adequate for domestic and other purposes in the Osage Nation at the current rate of usage. In areas where these aquifers are absent, groundwater must be pumped from minor bedrock aquifers that produce smaller volumes of water. About 30 and 60 percent of 32 and 54 water samples collected from the alluvial and Vamoosa-Ada aquifers, respectively, contained total dissolved solids concentrations larger than the secondary drinking-water standard of 500 mg/L. Local factors, such as natural seepage of brines or leakage from petroleum and natural-gas extraction activities, may cause substantial variations in dissolved chloride concentration in groundwater in the Osage Nation. Total phosphorus concentrations measured in groundwater samples were similar to dissolved phosphorus concentrations measured in the base flow of several streams. Total fresh surface-water withdrawals (use) and fresh groundwater withdrawals in the Osage Nation were estimated to have increased from 0.75 to 16.19 million gallons per day and from 0.13 to 2.39 million gallons per day, respectively, over the period from 1890 through 2010. Estimated saline-groundwater reinjection volumes at the heavily developed Burbank Oil Field in the Osage Nation from 1950 through 2012 were many times larger than the total amounts of freshwater withdrawn in this area, with estimated increases in saline-groundwater reinjection in the 2000s probably being related to increased petroleum extraction. Estimates of freshwater resources in local streams, lakes, and freshwater aquifers and of net annual precipitation indicate that less than 1 percent of freshwater resources and net annual precipitation currently is being withdrawn annually in the Osage Nation. In addition to freshwater resources, the Osage Nation may be underlain by 45,000,000 million gallons of brines, a small portion of which are withdrawn and reinjected during petroleum and natural-gas extraction. Ongoing development of desalinization technology may lead to the ability to expand use of these saline waters in the future. Several additional studies could improve understanding of the hydrologic resources of the Osage Nation. Development of computer models (simulations) of groundwater and surface-water flow for this area could enable testing of scenarios of localized and widespread effects of future climate variations and water-use changes on streamflows, lake-water levels, and groundwater levels in the Osage Nation. Installation of additional long-term streamflow and water-quality sampling stations, some with continuous water-quality monitors, could expand and improve understanding of surface-water quality. Periodic measurement of groundwater levels and sampling of water from a network of wells could provide better information about trends of groundwater quantity and quality with time. Measurement of water withdrawals at selected sites could enable more accurate estimates of water use. Lastly, better understanding of aquifer properties and spatial distribution of saline groundwater provided by geophysical surveys could improve understanding of fresh and saline groundwater resources underlying the Osage Nation.

Dissolved pesticide concentrations detected in storm-water runoff at selected sites in the San Joaquin River basin, California, 2000-2001

USGS Publications Warehouse

Orlando, James L.; Kuivila, Kathryn; Whitehead, Andrew

2003-01-01

As part of a collaborative study involving the United States Geological Survey Toxics Substances Hydrology Project (Toxics Project) and the University of California, Davis, Bodega Marine Laboratory (BML), water samples were collected at three sites within the San Joaquin River Basin of California and analyzed for dissolved pesticides. Samples were collected during, and immediately after, the first significant rainfall (greater than 0.5 inch per day) following the local application of dormant spray, organophosphate insecticides during the winters of 2000 and 2001. All samples were collected in conjunction with fish-caging experiments conducted by BML researchers. Sites included two locations potentially affected by runoff of agricultural chemicals (San Joaquin River near Vernalis, California, and Orestimba Creek at River Road near Crows Landing, California, and one control site located upstream of pesticide input (Orestimba Creek at Orestimba Creek Road near Newman, California). During these experiments, fish were placed in cages and exposed to storm runoff for up to ten days. Following exposure, the fish were examined for acetylcholinesterase concentrations and overall genetic damage. Water samples were collected throughout the rising limb of the stream hydrograph at each site for later pesticide analysis. Concentrations of selected pesticides were measured in filtered water samples using solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC/MS) at the U.S. Geological Survey organic chemistry laboratory in Sacramento, California. Results of these analyses are presented.

Major and trace element partitioning between dissolved and particulate phases in Antarctic surface snow.

PubMed

Grotti, M; Soggia, F; Ardini, F; Magi, E

2011-09-01

In order to provide a new insight into the Antarctic snow chemistry, partitioning of major and trace elements between dissolved and particulate (i.e. insoluble particles, >0.45 μm) phases have been investigated in a number of coastal and inland snow samples, along with their total and acid-dissolvable (0.5% nitric acid) concentrations. Alkaline and alkaline-earth elements (Na, K, Ca, Mg, Sr) were mainly present in the dissolved phase, while Fe and Al were predominantly associated with the particulate matter, without any significant difference between inland and coastal samples. On the other hand, partitioning of trace elements depended on the sampling site position, showing a general decrease of the particulate fraction by moving from the coast to the plateau. Cd, Cu, Pb and Zn were for the most part in the dissolved phase, while Cr was mainly associated with the particulate fraction. Co, Mn and V were equally distributed between dissolved and particulate phases in the samples collected from the plateau and preferentially associated with the particulate in the coastal samples. The correlation between the elements and the inter-sample variability of their concentration significantly decreased for the plateau samples compared to the coastal ones, according to a change in the relative contribution of the metal sources and in good agreement with the estimated marine and crustal enrichment factors. In addition, samples from the plateau were characterised by higher enrichment factors of anthropogenic elements (Cd, Cr, Cu, Pb and Zn), compared to the coastal area. Finally, it was observed that the acid-dissolvable metal concentrations were generally lower than the total concentration values, showing that the acid treatment can dissolve only a given fraction of the metal associated with the particulate (<20% for iron and aluminium).

Geochemical and isotopic variations in shallow groundwater in areas of the Fayetteville Shale development, north-central Arkansas

USGS Publications Warehouse

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) total dissolved solids (TDS), (2) TDS > 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 = 0.7097–0.7166), C (δ13CDIC = −21.3‰ to −4.7‰), and B (δ11B = 3.9–32.9‰) isotopes clearly reflect water–rock interactions within the aquifer rocks, while the stable O and H isotopic composition mimics the local meteoric water composition. Overall, there was a geochemical gradient from low-mineralized recharge water to more evolved Ca–HCO3, and higher-mineralized Na–HCO3 composition generated by a combination of carbonate dissolution, silicate weathering, and reverse base-exchange reactions. The chemical and isotopic compositions of the bulk shallow groundwater samples were distinct from the Na–Cl type Fayetteville flowback/produced waters (TDS ∼10,000–20,000 mg/L). Yet, the high Br/Cl variations in a small subset of saline shallow groundwater suggest that they were derived from dilution of saline water similar to the brine in the Fayetteville Shale. Nonetheless, no spatial relationship was found between CH4 and salinity occurrences in shallow drinking water wells with proximity to shale-gas drilling sites. The integration of multiple geochemical and isotopic proxies shows no direct evidence of contamination in shallow drinking-water aquifers associated with natural gas extraction from the Fayetteville Shale.

The distribution and sea-air transfer of volatile mercury in waste post-desulfurization seawater discharged from a coal-fired power plant.

PubMed

Sun, Lumin; Lin, Shanshan; Feng, Lifeng; Huang, Shuyuan; Yuan, Dongxing

2013-09-01

The waste seawater discharged in coastal areas from coal-fired power plants equipped with a seawater desulfurization system might carry pollutants such as mercury from the flue gas into the adjacent seas. However, only very limited impact studies have been carried out. Taking a typical plant in Xiamen as an example, the present study targeted the distribution and sea-air transfer flux of volatile mercury in seawater, in order to trace the fate of the discharged mercury other than into the sediments. Samples from 28 sampling sites were collected in the sea area around two discharge outlets of the plant, daily and seasonally. Total mercury, dissolved gaseous mercury and dissolved total mercury in the seawater, as well as gaseous elemental mercury above the sea surface, were investigated. Mean concentrations of dissolved gaseous mercury and gaseous elemental mercury in the area were 183 and 4.48 ng m(-3) in summer and 116 and 3.92 ng m(-3) in winter, which were significantly higher than those at a reference site. Based on the flux calculation, the transfer of volatile mercury was from the sea surface into the atmosphere, and more than 4.4 kg mercury, accounting for at least 2.2 % of the total discharge amount of the coal-fired power plant in the sampling area (1 km(2)), was emitted to the air annually. This study strongly suggested that besides being deposited into the sediment and diluted with seawater, emission into the atmosphere was an important fate for the mercury from the waste seawater from coal-fired power plants.

Triacetin as food additive in gummy candy and other foodstuffs on the market.

PubMed

Ogawa, T; Moriwaki, N; Fujii, R; Tanaka, K; Mori, E; Saitou, M; Yoshizawa, H; Sakaguchi, H

1992-04-01

The qualitative and quantitative analytical methods were proposed for the simple and rapid determination of triacetin (TAc) in commercial gummy candies and other foodstuffs by gas chromatography (GC), thin layer chromatography (TLC) and infrared spectroscopy (IR). Each extract from the samples was obtained by pretreatment of the foodstuffs as follows: (A) Gummy candy was dissolved in warm water and the solution was extracted with chloroform. The organic (chloroform) layer was separated. (B) Samples (such as ice cream) containing substantial water were mixed with anhydrous Na2SO4 and stirred to sandy appearance and dried. The residue was homogenized with ether, followed by centrifuging, and the organic (ether) layer was separated. (C) Dried samples (such as chocolate and cookie) were smashed, homogenized with ether, and followed by centrifuging, and the organic (ether) layer was separated. (D) Candy was dissolved in warm water and the solution was extracted with ether. The organic (ether) layer was separated. Each organic layer from (A)-(D) was washed with 10% NaHCO3 and evaporated. The residue containing TAc was dissolved in dichloromethane. The extract obtained was subjected to column chromatography on silica gel. The fractions containing TAc were employed in GC with 25% PEG-20M column, TLC, and IR analyses. Recovery of TAc from gummy candy was 99.1 +/- 3.0% and those from other foodstuffs ranged from was 82.1 to 99.4% by GC. Detection limit by this method was 10 ppm. TAc was found to contain at a level as high as 550 ppm in one domestic gummy candy. On the other hand, one imported gummy candy contained no more than 20 ppm of TAc gummy candy.

Total dissolved atmospheric nitrogen deposition in the anoxic Cariaco basin

NASA Astrophysics Data System (ADS)

Rasse, R.; Pérez, T.; Giuliante, A.; Donoso, L.

2018-04-01

Atmospheric deposition of total dissolved nitrogen (TDN) is an important source of nitrogen for ocean primary productivity that has increased since the industrial revolution. Thus, understanding its role in the ocean nitrogen cycle will help assess recent changes in ocean biogeochemistry. In the anoxic Cariaco basin, the place of the CARIACO Ocean Time-Series Program, the influence of atmospherically-deposited TDN on marine biogeochemistry is unknown. In this study, we measured atmospheric TDN concentrations as dissolved organic (DON) and inorganic (DIN) nitrogen (TDN = DIN + DON) in atmospheric suspended particles and wet deposition samples at the northeast of the basin during periods of the wet (August-September 2008) and dry (March-April 2009) seasons. We evaluated the potential anthropogenic N influences by measuring wind velocity and direction, size-fractionated suspended particles, chemical traces and by performing back trajectories. We found DIN and DON concentration values that ranged between 0.11 and 0.58 μg-N m-3 and 0.11-0.56 μg-N m-3 in total suspended particles samples and between 0.08 and 0.54 mg-N l-1 and 0.02-1.3 mg-N l-1 in wet deposition samples, respectively. Continental air masses increased DON and DIN concentrations in atmospheric suspended particles during the wet season. We estimate an annual TDN atmospheric deposition (wet + particles) of 3.6 × 103 ton-N year-1 and concluded that: 1) Atmospheric supply of TDN plays a key role in the C and N budget of the basin because replaces a fraction of the C (20% by induced primary production) and N (40%) removed by sediment burial, 2) present anthropogenic N could contribute to 30% of TDN atmospheric deposition in the basin, and 3) reduced DON (gas + particles) should be a significant component of bulk N deposition.

Influence of environmental parameters on the concentration of subsurface dissolved methane in two hydroelectric power plants in Brazil

NASA Astrophysics Data System (ADS)

Silva, M. G.; Marani, L.; Alvala, P. C.

2013-12-01

Methane (CH4) is a trace gas in the atmosphere of great importance for atmospheric chemistry as one of the main greenhouse gases. There are different sources with the largest individual production associated with the degradation of organic matter submerged in flooded areas. The amount of dissolved methane that reaches the surface depends on the production in the sediments and consumption in the water column. Both processes are associated with microbial activity and consequently dependent on the physico-chemical environmental conditions. The construction of hydroelectric dams cause flooding of areas near the river that can change the characteristics of the environment and cause changes in subsurface methane concentration. In this work, we studied two hydroelectric plants located in Brazil: Batalha (17°20'39.52"S, 47°29'34.29"W), under construction when the samples were take, and Itaipu (25°24'45.00"S, 54°35'39.00"W) which has been floated over 30 years ago. The water samples to determine dissolved methane were collected approximately 5 cm near the surface. In each collection point was measured depth, water temperature, pH and redox potential. The range of dissolved methane between the two dams was similar: 0.07-10.33 μg/l (Batalha) and 0.15-10.93 μg/l (Itaipu). However, the Batalha's average (4.04 × 3.43 μg/l; median = 3.66 μg/l) was higher than that observed in Itaipu (2.15 × 1.59 μg/l; median = 2.53 μg/l). The influence of environmental parameters on the concentration of dissolved methane was evaluated by multivariate statistical techniques (Principal Component Analysis - PCA). All of the parameters had some correlation with dissolved methane, however, the greatest contribution in Batalha was associated with pH while in Itaipu was the depth. The pH variation of the various points studied in Batalha may be associated with periods of drought and flooding of the river and hence the incorporation of organic matter in the environment. The organisms responsible for the production and oxidation of methane in water are very susceptible to changes in pH, resulting in variations in the amount of gas that is transported to the surface. In Itaipu, depth variation was shown to have more influence than the other parameters. The increase of the water column results in a longer path through which methane is transported, increasing the oxidation potencial by bacteria in the water, decreasing the amount of CH4 can be emitted to the atmosphere. The comparison between the two dams showed that the environmental parameters influences the the production and consumption of methane in water and the importance of each parameter can vary according to the characteristics of each reservoir.

How to Enhance Gas Removal from Porous Electrodes?

PubMed Central

Kadyk, Thomas; Bruce, David; Eikerling, Michael

2016-01-01

This article presents a structure-based modeling approach to optimize gas evolution at an electrolyte-flooded porous electrode. By providing hydrophobic islands as preferential nucleation sites on the surface of the electrode, it is possible to nucleate and grow bubbles outside of the pore space, facilitating their release into the electrolyte. Bubbles that grow at preferential nucleation sites act as a sink for dissolved gas produced in electrode reactions, effectively suctioning it from the electrolyte-filled pores. According to the model, high oversaturation is necessary to nucleate bubbles inside of the pores. The high oversaturation allows establishing large concentration gradients in the pores that drive a diffusion flux towards the preferential nucleation sites. This diffusion flux keeps the pores bubble-free, avoiding deactivation of the electrochemically active surface area of the electrode as well as mechanical stress that would otherwise lead to catalyst degradation. The transport regime of the dissolved gas, viz. diffusion control vs. transfer control at the liquid-gas interface, determines the bubble growth law. PMID:28008914

Gas content and composition of gas hydrate from sediments of the southeastern North American continental margin

USGS Publications Warehouse

Lorenson, T.D.; Collett, T.S.

2000-01-01

Gas hydrate samples were recovered from four sites (Sites 994, 995, 996, and 997) along the crest of the Blake Ridge during Ocean Drilling Program (ODP) Leg 164. At Site 996, an area of active gas venting, pockmarks, and chemosynthetic communities, vein-like gas hydrate was recovered from less than 1 meter below seafloor (mbsf) and intermittently through the maximum cored depth of 63 mbsf. In contrast, massive gas hydrate, probably fault filling and/or stratigraphically controlled, was recovered from depths of 260 mbsf at Site 994, and from 331 mbsf at Site 997. Downhole-logging data, along with geochemical and core temperature profiles, indicate that gas hydrate at Sites 994, 995, and 997 occurs from about 180 to 450 mbsf and is dispersed in sediment as 5- to 30-m-thick zones of up to about 15% bulk volume gas hydrate. Selected gas hydrate samples were placed in a sealed chamber and allowed to dissociate. Evolved gas to water volumetric ratios measured on seven samples from Site 996 ranged from 20 to 143 mL gas/mL water to 154 mL gas/mL water in one sample from Site 994, and to 139 mL gas/mL water in one sample from Site 997, which can be compared to the theoretical maximum gas to water ratio of 216. These ratios are minimum gas/water ratios for gas hydrate because of partial dissociation during core recovery and potential contamination with pore waters. Nonetheless, the maximum measured volumetric ratio indicates that at least 71% of the cages in this gas hydrate were filled with gas molecules. When corrections for pore-water contamination are made, these volumetric ratios range from 29 to 204, suggesting that cages in some natural gas hydrate are nearly filled. Methane comprises the bulk of the evolved gas from all sites (98.4%-99.9% methane and 0%-1.5% CO2). Site 996 hydrate contained little CO2 (0%-0.56%). Ethane concentrations differed significantly from Site 996, where they ranged from 720 to 1010 parts per million by volume (ppmv), to Sites 994 and 997, which contained much less ethane (up to 86 ppmv). Up to 19 ppmv propane and other higher homologues were noted; however, these gases are likely contaminants derived from sediment in some hydrate samples. CO2 concentrations are less in gas hydrate than in the surrounding sediment, likely an artifact of core depressurization, which released CO2 derived from dissolved organic carbon (DIC) into sediment. The isotopic composition of methane from gas hydrate ranges from ??13C of -62.5??? to -70.7??? and ??D of -175??? to -200??? and is identical to the isotopic composition of methane from surrounding sediment. Methane of this isotopic composition is mainly microbial in origin and likely produced by bacterial reduction of bicarbonate. The hydrocarbon gases here are likely the products of early microbial diagenesis. The isotopic composition of CO2 from gas hydrate ranges from ??13C of -5.7 to -6.9, about 15??? lighter than CO2 derived from nearby sediment.

Microporous polymer films and methods of their production

DOEpatents

Aubert, James H.

1995-01-01

A process for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquified gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase.

Water-chemistry data for selected springs, geysers, and streams in Yellowstone National Park, Wyoming, 2006-2008

USGS Publications Warehouse

Ball, James W.; McMleskey, R. Blaine; Nordstrom, D. Kirk

2010-01-01

Water analyses are reported for 104 samples collected from numerous thermal and non-thermal features in Yellowstone National Park (YNP) during 2006-2008. Water samples were collected and analyzed for major and trace constituents from 10 areas of YNP including Apollinaris Spring and Nymphy Creek along the Norris-Mammoth corridor, Beryl Spring in Gibbon Canyon, Norris Geyser Basin, Lower Geyser Basin, Crater Hills, the Geyser Springs Group, Nez Perce Creek, Rabbit Creek, the Mud Volcano area, and Washburn Hot Springs. These water samples were collected and analyzed as part of research investigations in YNP on arsenic, antimony, iron, nitrogen, and sulfur redox species in hot springs and overflow drainages, and the occurrence and distribution of dissolved mercury. Most samples were analyzed for major cations and anions, trace metals, redox species of antimony, arsenic, iron, nitrogen, and sulfur, and isotopes of hydrogen and oxygen. Analyses were performed at the sampling site, in an on-site mobile laboratory vehicle, or later in a U.S. Geological Survey laboratory, depending on stability of the constituent and whether it could be preserved effectively. Water samples were filtered and preserved on-site. Water temperature, specific conductance, pH, emf (electromotive force or electrical potential), and dissolved hydrogen sulfide were measured on-site at the time of sampling. Dissolved hydrogen sulfide was measured a few to several hours after sample collection by ion-specific electrode on samples preserved on-site. Acidity was determined by titration, usually within a few days of sample collection. Alkalinity was determined by titration within 1 to 2 weeks of sample collection. Concentrations of thiosulfate and polythionate were determined as soon as possible (generally a few to several hours after sample collection) by ion chromatography in an on-site mobile laboratory vehicle. Total dissolved iron and ferrous iron concentrations often were measured on-site in the mobile laboratory vehicle. Concentrations of dissolved aluminum, arsenic, boron, barium, beryllium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, selenium, silica, strontium, vanadium, and zinc were determined by inductively coupled plasma-optical emission spectrometry. Trace concentrations of dissolved antimony, cadmium, cobalt, chromium, copper, lead, and selenium were determined by Zeeman-corrected graphite-furnace atomic-absorption spectrometry. Dissolved concentrations of total arsenic, arsenite, total antimony, and antimonite were determined by hydride generation atomic-absorption spectrometry using a flow-injection analysis system. Dissolved concentrations of total mercury and methylmercury were determined by cold-vapor atomic fluorescence spectrometry. Concentrations of dissolved chloride, fluoride, nitrate, bromide, and sulfate were determined by ion chromatography. For many samples, concentrations of dissolved fluoride also were determined by ion-specific electrode. Concentrations of dissolved ferrous and total iron were determined by the FerroZine colorimetric method. Concentrations of dissolved ammonium were determined by ion chromatography, with reanalysis by colorimetry when separation of sodium and ammonia peaks was poor. Dissolved organic carbon concentrations were determined by the wet persulfate oxidation method. Hydrogen and oxygen isotope ratios were determined using the hydrogen and CO2 equilibration techniques, respectively.

Raman spectroscopy measurement of CH4 gas and CH4 dissolved in water for laser remote sensing in water

NASA Astrophysics Data System (ADS)

Somekawa, Toshihiro; Fujita, Masayuki

2018-04-01

We examined the applicability of Raman spectroscopy as a laser remote sensing tool for monitoring CH4 in water. The Raman technique has already been used successfully for measurements of CO2 gas in water. In this paper, considering the spectral transmittance of water, third harmonics of Q-switched Nd:YAG laser at 355 nm (UV region) was used for detection of CH4 Raman signals. The Raman signal at 2892 cm-1 from CH4 dissolved in water was detected at a tail of water Raman signal.

Organic and inorganic composition and microbiology of produced waters from Pennsylvania shale gas wells

USGS Publications Warehouse

Akob, Denise M.; Cozzarelli, Isabelle M.; Dunlap, Darren S.; Rowan, Elisabeth L.; Lorah, Michelle M.

2015-01-01

Hydraulically fractured shales are becoming an increasingly important source of natural gas production in the United States. This process has been known to create up to 420 gallons of produced water (PW) per day, but the volume varies depending on the formation, and the characteristics of individual hydraulic fracture. PW from hydraulic fracturing of shales are comprised of injected fracturing fluids and natural formation waters in proportions that change over time. Across the state of Pennsylvania, shale gas production is booming; therefore, it is important to assess the variability in PW chemistry and microbiology across this geographical span. We quantified the inorganic and organic chemical composition and microbial communities in PW samples from 13 shale gas wells in north central Pennsylvania. Microbial abundance was generally low (66–9400 cells/mL). Non-volatile dissolved organic carbon (NVDOC) was high (7–31 mg/L) relative to typical shallow groundwater, and the presence of organic acid anions (e.g., acetate, formate, and pyruvate) indicated microbial activity. Volatile organic compounds (VOCs) were detected in four samples (∼1 to 11.7 μg/L): benzene and toluene in the Burket sample, toluene in two Marcellus samples, and tetrachloroethylene (PCE) in one Marcellus sample. VOCs can be either naturally occurring or from industrial activity, making the source of VOCs unclear. Despite the addition of biocides during hydraulic fracturing, H2S-producing, fermenting, and methanogenic bacteria were cultured from PW samples. The presence of culturable bacteria was not associated with salinity or location; although organic compound concentrations and time in production were correlated with microbial activity. Interestingly, we found that unlike the inorganic chemistry, PW organic chemistry and microbial viability were highly variable across the 13 wells sampled, which can have important implications for the reuse and handling of these fluids

Labile, dissolved and particulate PAHs and trace metals in wastewater: passive sampling, occurrence, partitioning in treatment plants.

PubMed

Gourlay-Francé, C; Bressy, A; Uher, E; Lorgeoux, C

2011-01-01

The occurrence and the partitioning of polycyclic aromatic hydrocarbons (PAHs) and seven metals (Al, Cd, Cr, Cu, Ni, Pb and Zn) were investigated in activated sludge wastewater treatment plants by means of passive and active sampling. Concentrations total dissolved and particulate contaminants were determined in wastewater at several points across the treatment system by means of grab sampling. Truly dissolved PAHs were sampled by means of semipermeable membrane devices. Labile (inorganic and weakly complexed) dissolved metals were also sampled using the diffusive gradient in thin film technique. This study confirms the robustness and the validity of these two passive sampling techniques in wastewater. All contaminant concentrations decreased in wastewater along the treatment, although dissolved and labile concentrations sometimes increased for substances with less affinity with organic matter. Solid-liquid and dissolved organic matter/water partitioning constants were estimated. The high variability of both partitioning constants for a simple substance and the poor relation between K(D) and K(OW) shows that the binding capacities of particles and organic matter are not uniform within the treatment and that other process than equilibrium sorption affect contaminant repartition and fate in wastewater.

RAPID AND PRECISE METHOD FOR MEASURING STABLE CARBON ISOTOPE RATIOS OF DISSOLVED INORGANIC CARBON

EPA Science Inventory

We describe a method for rapid preparation, concentration and stable isotopic analysis of dissolved inorganic carbon (d13C-DIC). Liberation of CO2 was accomplished by placing 100 ?l phosphoric acid and 0.9 ml water in an evacuated 1.7-ml gas chromatography (GC) injection vial. Fo...

The solubility of noble gases in crude oil at 25-100°C

USGS Publications Warehouse

Kharaka, Yousif K.; Specht, Daniel J.

1988-01-01

The solubility of the noble gases He, Ne, Ar, Kr and Xe was measured in two typical crude oils at temperatures of 25–100°C. The oil samples were obtained from the Elk Hills oil field located in southern San Joaquin Valley, California. The experimental procedure consisted of placing a known amount of gas with a known volume of crude oil in a stainless steel hydrothermal pressure vessel. The vessel was housed inside an oven and the entire unit rotates providing continuous mixing. The amount of gas dissolved in oil at a measured temperature and partial pressure of gas was used to calculate the solubility constants for these gases. Results show that the solubility of He and Ne in both oils is approximately the same; solubility then increases with atomic mass, with the solubility of Xe at 25°C being two orders of magnitude higher than that of He. The gas solubilities are somewhat higher in the lower density (higher API gravity) oil. The solubility of Ar is approximately constant in the range of temperatures of this study. The solubilities of He and Ne increase, but those of Kr and Xe decrease with increasing temperatures. Solubilities of noble gases in crude oil are significantly higher than their solubilities in water. For example, the solubilities of He and Xe at 25°C in the light oil of this study are, respectively, 3 and 24 times higher than their solubilities in pure water, and they are 15 and 300 times higher than in a brine with a salinity of 350,000 mg/l dissolved solids. These large and variable differences in the solubilities of noble gases in oil and water indicate that, in sedimentary basins with oil, these gases must be partitioned between oil, water and natural gas before they are used to deduce the origin and residence time of these fluids.

Sampling and analysis for radon-222 dissolved in ground water and surface water

USGS Publications Warehouse

DeWayne, Cecil L.; Gesell, T.F.

1992-01-01

Radon-222 is a naturally occurring radioactive gas in the uranium-238 decay series that has traditionally been called, simply, radon. The lung cancer risks associated with the inhalation of radon decay products have been well documented by epidemiological studies on populations of uranium miners. The realization that radon is a public health hazard has raised the need for sampling and analytical guidelines for field personnel. Several sampling and analytical methods are being used to document radon concentrations in ground water and surface water worldwide but no convenient, single set of guidelines is available. Three different sampling and analytical methods - bubbler, liquid scintillation, and field screening - are discussed in this paper. The bubbler and liquid scintillation methods have high accuracy and precision, and small analytical method detection limits of 0.2 and 10 pCi/l (picocuries per liter), respectively. The field screening method generally is used as a qualitative reconnaissance tool.

Experimental Investigation of Gas/Slag/Matte/Spinel Equilibria in the Cu-Fe-O-S-Si System at 1473 K (1200 °C) and P(SO2) = 0.25 atm

NASA Astrophysics Data System (ADS)

Hidayat, Taufiq; Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni

2018-04-01

New experimental data were obtained on the gas/slag/matte/spinel equilibria in the Cu-Fe-O-S-Si system at 1473 K (1200 °C) and P(SO2) = 0.25 atm covering Cu concentrations in matte between 42 and 78 wt pct Cu. Accurate measurements were obtained using high-temperature equilibration and the rapid quenching technique, followed by electron-probe X-ray microanalysis of equilibrium phase compositions. The use of spinel substrates made to support the samples ensures equilibrium with this primary phase solid, eliminates crucible contamination, and facilitates direct gas-condensed phase equilibrium and high quenching rates. Particular attention was given to the confirmation of the achievement of equilibrium. The results quantify the relationship between Cu in matte and oxygen partial pressure, sulfur in matte, oxygen in matte, Fe/SiO2 at slag liquidus, sulfur in slag, and dissolved copper in slag.

Gas-diffusion-based passive sampler for ammonia monitoring in marine waters.

PubMed

O'Connor Šraj, Lenka; Almeida, M Inês G S; Bassett, Chelsea; McKelvie, Ian D; Kolev, Spas D

2018-05-01

A novel passive sampler based on gas-diffusion across a hydrophobic membrane is described for the determination of the time-weighted average concentration of dissolved molecular ammonia in high ionic strength aquatic environments, such as sea, coastal and estuarine waters, for a period of 3 days. The passive sampler developed is cheap, easy-to-use, reusable, and has a dynamic concentration range of 2.0-12µM, which covers the water quality guideline trigger value of 11.4µM (160µgL -1 NH 3 -N) for high conservation value waters, making this a powerful new tool for water quality managers involved in long-term ammonia monitoring. The gas-diffusion-based passive sampler was calibrated under laboratory conditions and deployed in a tank of seawater in the laboratory and at an estuarine site for proof of concept, and a good agreement between passive and spot sampling was achieved in both cases. Copyright © 2017 Elsevier B.V. All rights reserved.

Solubility of platinum-arsenide melt and sperrylite in synthetic basalt at 0.1 MPa and 1200 °C with implications for arsenic speciation and platinum sequestration in mafic igneous systems

NASA Astrophysics Data System (ADS)

Canali, A. C.; Brenan, J. M.; Sullivan, N. A.

2017-11-01

To better understand the Pt-As association in natural magmas, experiments were done at 1200 °C and 0.1 MPa to measure the solubility of Pt and Pt-arsenide phases (melt and sperrylite, PtAs2), as well as to determine the oxidation state, and identify evidence for Pt-As complexing, in molten silicate. Samples consisting of synthetic basalt contained in chromite crucibles were subject to three experimental procedures. In the first, platinum solubility in the synthetic basalt was determined without added arsenic by equilibrating the sample with a platinum source (embedded wire or bead) in a gas-mixing furnace. In the second, the sample plus a Pt-arsenide source was equilibrated in a vacuum-sealed fused quartz tube containing a solid-oxide oxygen buffer. The third approach involved two steps: first equilibrating the sample in a gas-mixing furnace, then with added arsenide melt in a sealed quartz tube. Oxygen fugacity was estimated in the latter step using chromite/melt partitioning of vanadium. Method two experiments done at high initial arsenic activity (PtAs melt + PtAs2), showed significant loss of arsenic from the sample, the result of vapour transfer to newly-formed arsenide phases in the buffer. Method three experiments showed no loss of arsenic, yielding a uniform final distribution in the sample. Analyses of run-product glasses from experiments which did not show arsenic loss reveal significant increase in arsenic concentrations with fO2, varying from ∼10 ppm (FMQ-3.25) to >10,000 ppm (FMQ + 5.5). Despite very high arsenic loadings (>1000 ppm), the solubility of Pt is similar in arsenic-bearing and arsenic-free glasses. The variation in arsenic solubility with fO2 shows a linear relationship, that when corrected for the change in the activity of dissolved arsenic with the melt ferric/ferrous ratio, yields a solubility-fO2 relationship consistent with As3+ as the dissolved species. This result is confirmed by X-ray absorption near edge structure (XANES) determination on run-product glasses. Levels of arsenic required for Pt-arsenide saturation are 50-500 ppm over the fO2 range of most terrestrial basalts (FMQ to FMQ-2), >100× higher than the arsenic concentrations typical of such magmas, indicating significant enrichment of arsenic is required if Pt-arsenide saturation is to occur. In contrast, the level of dissolved Pt required to saturate in sperrylite is >8× lower than for pure Pt, suggesting that arsenic enrichment could lead to Pt removal at concentrations much less than required for pure metal saturation.

Assessment of online monitoring strategies for measuring N2O emissions from full-scale wastewater treatment systems.

PubMed

Marques, Ricardo; Rodriguez-Caballero, A; Oehmen, Adrian; Pijuan, Maite

2016-08-01

Clark-Type nitrous oxide (N2O) sensors are routinely used to measure dissolved N2O concentrations in wastewater treatment plants (WWTPs), but have never before been applied to assess gas-phase N2O emissions in full-scale WWTPs. In this study, a full-scale N2O gas sensor was tested and validated for online gas measurements, and assessed with respect to its linearity, temperature dependence, signal saturation and drift prior to full-scale application. The sensor was linear at the concentrations tested (0-422.3, 0-50 and 0-10 ppmv N2O) and had a linear response up to 2750 ppmv N2O. An exponential correlation between temperature and sensor signal was described and predicted using a double exponential equation while the drift did not have a significant influence on the signal. The N2O gas sensor was used for online N2O monitoring in a full-scale sequencing batch reactor (SBR) treating domestic wastewater and results were compared with those obtained by a commercial online gas analyser. Emissions were successfully described by the sensor, being even more accurate than the values given by the commercial analyser at N2O concentrations above 500 ppmv. Data from this gas N2O sensor was also used to validate two models to predict N2O emissions from dissolved N2O measurements, one based on oxygen transfer rate and the other based on superficial velocity of the gas bubble. Using the first model, predictions for N2O emissions agreed by 98.7% with the measured by the gas sensor, while 87.0% similarity was obtained with the second model. This is the first study showing a reliable estimation of gas emissions based on dissolved N2O online data in a full-scale wastewater treatment facility. Copyright © 2016 Elsevier Ltd. All rights reserved.

The persistence of natural CO2 accumulations over millennial timescales: Integrating noble gas and reservoir data at Bravo Dome, NM

NASA Astrophysics Data System (ADS)

Akhbari, D.

2017-12-01

Bravo Dome, the largest CO2 reservoir in the US, is a hydrogeologically closed system that has stored a very large amount of CO2 on millennial time scales. The pre-production gas pressures in Bravo Dome indicate that the reservoir is highly under-pressured and is divided into separate pressure compartments that do not communicate hydrologically. Previous studies used the noble gas composition at Bravo Dome to constrain the amount of dissolved CO2 into the brine. This CO2 dissolution into brine plays an important role in the observed under-pressure at the reservoir. However, the dissolution rates and transport mechanisms remain unknown. In this study, we are looking into reservoir pressures and noble gas composition in the northeastern section of the reservoir to constrain timescales of CO2 dissolution. We are interested in northeastern part of the reservoir because the largest amount of CO2 was dissolved into brine in this section. Also, we specifically look into the evolution of the CO2/3He and 20Ne concentration during convective CO2 dissolution at Bravo Dome. 20Ne has atmospheric origin and is initially in the brine, while 3He and CO2 have magmatic sources and were introduced with the gas. CO2/3He decreases as more CO2 dissolves into brine, due to the higher solubility of CO2 compare to that of 3He. However, 20Ne concentration in the gas increases due to exsolution of 20Ne from brine into the gas phase. We present 2D numerical simulation that demonstrate the persistence of CO2 over 1Ma and reproduce the observed reservoir pressures and noble gas compositions. Our results indicate that convection is required to produce observed changes in gas composition. But diffusion makes a significant contribution to mass transport.

Adsorption of Dissolved Gases (CH4, CO2, H2, Noble Gases) by Water-Saturated Smectite Clay Minerals

NASA Astrophysics Data System (ADS)

Bourg, I. C.; Gadikota, G.; Dazas, B.

2016-12-01

Adsorption of dissolved gases by water-saturated clay minerals plays important roles in a range of fields. For example, gas adsorption in on clay minerals may significantly impact the formation of CH4 hydrates in fine-grained sediments, the behavior of CH4 in shale, CO2 leakage across caprocks of geologic CO2 sequestration sites, H2 leakage across engineered clay barriers of high-level radioactive waste repositories, and noble gas geochemistry reconstructions of hydrocarbon migration in the subsurface. Despite its importance, the adsorption of gases on clay minerals remains poorly understood. For example, some studies have suggested that clay surfaces promote the formation of CH4 hydrates, whereas others indicate that clay surfaces inhibit the formation of CH4 hydrates. Here, we present molecular dynamics (MD) simulations of the adsorption of a range of gases (CH4, CO2, H2, noble gases) on clay mineral surfaces. Our results indicate that the affinity of dissolved gases for clay mineral surfaces has a non-monotone dependence on the hydrated radius of the gas molecules. This non-monotone dependence arises from a combination of two effects: the polar nature of certain gas molecules (in particular, CO2) and the templating of interfacial water structure by the clay basal surface, which results in the presence of interfacial water "cages" of optimal size for intermediate-size gas molecules (such as Ne or Ar).

Prediction of dissolved oxygen and carbon dioxide concentration profiles in tubular photobioreactors for microalgal culture

PubMed

Rubio; Fernandez; Perez; Camacho; Grima

1999-01-05

A model is developed for prediction of axial concentration profiles of dissolved oxygen and carbon dioxide in tubular photobioreactors used for culturing microalgae. Experimental data are used to verify the model for continuous outdoor culture of Porphyridium cruentum grown in a 200-L reactor with 100-m long tubular solar receiver. The culture was carried out at a dilution rate of 0.05 h-1 applied only during a 10-h daylight period. The quasi-steady state biomass concentration achieved was 3.0 g. L-1, corresponding to a biomass productivity of 1.5 g. L-1. d-1. The model could predict the dissolved oxygen level in both gas disengagement zone of the reactor and at the end of the loop, the exhaust gas composition, the amount of carbon dioxide injected, and the pH of the culture at each hour. In predicting the various parameters, the model took into account the length of the solar receiver tube, the rate of photosynthesis, the velocity of flow, the degree of mixing, and gas-liquid mass transfer. Because the model simulated the system behavior as a function of tube length and operational variables (superficial gas velocity in the riser, composition of carbon dioxide in the gas injected in the solar receiver and its injection rate), it could potentially be applied to rational design and scale-up of photobioreactors. Copyright 1999 John Wiley & Sons, Inc.

Microporous polymer films and methods of their production

DOEpatents

Aubert, J.H.

1995-06-06

A process is described for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquefied gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase. 9 figs.

Biogeochemical interactions between of coal mine water and gas well cement

NASA Astrophysics Data System (ADS)

Gulliver, D. M.; Gardiner, J. B.; Kutchko, B. G.; Hakala, A.; Spaulding, R.; Tkach, M. K.; Ross, D.

2017-12-01

Unconventional natural gas wells drilled in Northern Appalachia often pass through abandoned coal mines before reaching the Marcellus or Utica formations. Biogeochemical interactions between coal mine waters and gas well cements have the potential to alter the cement and compromise its sealing integrity. This study investigates the mineralogical, geochemical, and microbial changes of cement cores exposed to natural coal mine waters. Static reactors with Class H Portland cement cores and water samples from an abandoned bituminous Pittsburgh coal mine simulated the cement-fluid interactions at relevant temperature for time periods of 1, 2, 4, and 6 weeks. Fluids were analyzed for cation and anion concentrations and extracted DNA was analyzed by 16S rRNA gene sequencing and shotgun sequencing. Cement core material was evaluated via scanning electron microscope. Results suggest that the sampled coal mine water altered the permeability and matrix mineralogy of the cement cores. Scanning electron microscope images display an increase in mineral precipitates inside the cement matrix over the course of the experiment. Chemistry results from the reaction vessels' effluent waters display decreases in dissolved calcium, iron, silica, chloride, and sulfate. The microbial community decreased in diversity over the 6-week experiment, with Hydrogenophaga emerging as dominant. These results provide insight in the complex microbial-fluid-mineral interactions of these environments. This study begins to characterize the rarely documented biogeochemical impacts that coal waters may have on unconventional gas well integrity.

Gaseous exchange of polycyclic aromatic hydrocarbons across the air-water interface of lower Chesapeake Bay

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

Gustafson, K.E.; Dickhut, R.M.

1995-12-31

The gaseous exchange fluxes of polycyclic aromatic hydrocarbons (PAHs) across the air-water interface of lower Chesapeake Bay were determined using a modified two-film exchange model. Sampling covered the period January 1994 to June 1995 for five sites on lower Chesapeake Bay ranging from rural to urban and highly industrialized. Simultaneous air and water samples were collected and the atmospheric gas phase and water column dissolved phase analyzed via GC/MS for 17 PAHs. The direction and magnitude of flux for each PAH was calculated using Henry`s law constants, hydrological and meteorological parameters, Temperature was observed to be an important environmental factormore » in determining both the direction and magnitude of PAH gas exchange. Nonetheless, wind speed significantly impacts mass transfer coefficients, and therefore was found to control the magnitude of flux. Spatial and temporal variation of PAH gaseous exchange fluxes were examined. Fluxes were determined to be both into and out of Chesapeake Bay. The range of gas exchange fluxes ({minus}560 to 600{micro}g/M{sup 2}*Mo) is of the same order to 10X greater than atmospheric wet and dry depositional fluxes to lower Chesapeake Bay. The results of this study support the hypothesis that gas exchange is a major transport process affecting the net loadings of PAHs in lower Chesapeake Bay.« less

[Flow injection-spectrophotometric determination of total dissolved nitrogen in seawater based on quantificational solenoid valves].

PubMed

Han, Bin; Cao, Lei; Zheng, Li; Zang, Jia-ye; Wang, Xiao-ru

2012-01-01

Using three pipe clamp solenoid valves to replace the traditional six-port valve for sample quota, a set of multi-channel flow injection analyzer was designed in the present paper. The authors optimized optimum instrumental testing condition, and realized determination and analysis of total dissolved nitrogen in seawaters. The construction of apparatus is simple and it has the potential to be used for analysis of total dissolved nitrogen. The sample throughput of total dissolved nitrogen was 27 samples per hour. The linear range of total dissolved nitrogen was 50.0-1 000.0 microgN x L(-3) (r > or = 0.999). The detection limit was 7.6 microgN x L(-3). The recovery of total dissolved nitrogen was 87.3%-107.2%. The relative standard deviation for total dissolved nitrogen was 1.35%-6.32% (n = 6). After the t-test analysis, it does not have the significance difference between this method and national standard method. It is suitable for fast analysis of total dissolved nitrogen in seawater.

[Influence of dissolved gases on highly diluted aqueous media].

PubMed

Belovolova, L V; Glushkov, M V; Vinogradov, E A

2014-01-01

In the experiments on redox potential measurement for a series of identical samples of purified and presettled water it was found that the response to ultraviolet irradiation varies appreciably within a few days after treatment, including stepwise changes. In a few hours after exposure, leading to a higher content of reactive oxygen species as compared with the equilibrium values, long-term changes including variations in redox potential and optical system parameters are recorded in water and diluted aqueous media. We propose a heuristic organization model of the water-gas system with an increased content of reactive oxygen species.

Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

PubMed Central

Mau, S.; Römer, M.; Torres, M. E.; Bussmann, I.; Pape, T.; Damm, E.; Geprägs, P.; Wintersteller, P.; Hsu, C.-W.; Loher, M.; Bohrmann, G.

2017-01-01

Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming. PMID:28230189

An Environmentally Friendly Process Involving Refining and Membrane-Based Electrolysis for Magnesium Recovery from Partially Oxidized Scrap Alloy

NASA Astrophysics Data System (ADS)

Guan, Xiaofei; Pal, Uday B.; Powell, Adam C.

2013-10-01

Magnesium is recovered from partially oxidized scrap alloy by combining refining and solid oxide membrane (SOM) electrolysis. In this combined process, a molten salt eutectic flux (45 wt.% MgF2-55 wt.% CaF2) containing 10 wt.% MgO and 2 wt.% YF3 was used as the medium for magnesium recovery. During refining, magnesium and its oxide are dissolved from the scrap into the molten flux. Forming gas is bubbled through the flux and the dissolved magnesium is removed via the gas phase and condensed in a separate condenser at a lower temperature. The molten flux has a finite solubility for magnesium and acts as a selective medium for magnesium dissolution, but not aluminum or iron, and therefore the magnesium recovered has high purity. After refining, SOM electrolysis is performed in the same reactor to enable electrolysis of the dissolved magnesium oxide in the molten flux producing magnesium at the cathode and oxygen at the SOM anode. During SOM electrolysis, it is necessary to decrease the concentration of the dissolved magnesium in the flux to improve the faradaic current efficiency and prevent degradation of the SOM. Thus, for both refining and SOM electrolysis, it is very important to measure and control the magnesium solubility in the molten flux. High magnesium solubility facilitates refining whereas lower solubility benefits the SOM electrolysis process. Computational fluid dynamics modeling was employed to simulate the flow behavior of the flux stirred by the forming gas. Based on the modeling results, an optimized design of the stirring tubes and its placement in the flux are determined for efficiently removing the dissolved magnesium and also increasing the efficiency of the SOM electrolysis process.

Measurement and reduction of micro-bubble formation in high-viscosity fluids

NASA Astrophysics Data System (ADS)

Tom, Glenn; Liu, Wei

2012-03-01

Gases at high drive pressure can initially dissolve into the fluids used in lithography and other critical processes during the fabrication of integrated circuits. In the low pressure portion of the dispense train, the dissolved gases can revert to bubbles. These bubbles can: 1. Affect the compressibility of the working fluid and change the flow characteristics of the dispense heads which require frequent re-tuning of the coating tools. 2. Contribute to defect formation if the bubbles are trapped on the surface of the wafer. Photosensitive Polyimides (PI) have high viscosities (1000 to 20,000 cP). Because of the high viscosity, high-powered, expensive pumps are needed to effectively remove the fluid from its container. Suction from the pump filling cycle easily causes cavitation, which can create flow rate variability, and micro-bubble formation. It is a common practice to apply pressure to the PI resists to minimize cavitation in the pump. The trade-off to this practice is the entrainment (dissolution) of the drive gas into the resist and the risk of micro-bubbles forming later in the dispense train. In the current study, ATMI measured the effects of two methods of pressure dispense from the container on the amount of gas entrained in a viscous fluid: (1) indirect pressure dispense and (2) direct pressure dispense. The main analytical method employed to measure the amount of dissolved gases is a gas chromatograph (GC), which can measure the concentration of gases dissolved in a volatile fluid. It is not suitable to measure gases in low volatility fluids. The new test method developed, however, is capable of measuring dissolved gases in low volatility fluids.

Organic Compounds, Trace Elements, Suspended Sediment, and Field Characteristics at the Heads-of-Tide of the Raritan, Passaic, Hackensack, Rahway, and Elizabeth Rivers, New Jersey, 2000-03

USGS Publications Warehouse

Bonin, Jennifer L.; Wilson, Timothy P.

2006-01-01

Concentrations of suspended sediment, particulate and dissolved organic carbon, trace elements, and organic compounds were measured in samples from the heads-of-tide of the five tributaries to the Newark and Raritan Bays during June 2000 to June 2003. The samples were collected as part of the New Jersey Department of Environmental Protection Toxics Reduction Workplan/Contaminant Assessment Reduction Program. Samples of streamwater were collected at water-quality sampling stations constructed near U.S. Geological Survey gaging stations on the Raritan, Passaic, Hackensack, Rahway, and Elizabeth Rivers. Sampling was conducted during base-flow conditions and storms. Constituent concentrations were measured to determine the water quality and to calculate the load of sediment and contaminants contributed to the bays from upstream sources. Water samples were analyzed for suspended sediment, dissolved organic carbon, particulate organic carbon, and specific conductance. Samples of suspended sediment and water were analyzed for 98 distinct polychlorinated biphenyl congeners, 7 dioxins, 10 furans, 27 pesticides, 26 polycyclic aromatic hydrocarbons, and the trace elements cadmium, lead, mercury, and methyl-mercury. Measurements of ultra-low concentrations of organic compounds in sediment and water were obtained by collecting 1 to 3 grams of suspended sediment on glass fiber filters and by passing at least 20 liters of filtered water through XAD-2 resin. The extracted sediment and XAD-2 resin were analyzed for organic compounds by high- and low-resolution gas chromatography mass-spectrometry that uses isotope dilution procedures. Trace elements in filtered and unfiltered samples were analyzed for cadmium, lead, mercury, and methyl-mercury by inductively coupled charged plasma and mass-spectrometry. All constituent concentrations are raw data. Interpretation of the data will be completed in the second phase of the study.

Manganese speciation of laboratory-generated welding fumes

PubMed Central

Andrews, Ronnee N.; Keane, Michael; Hanley, Kevin W.; Feng, H. Amy; Ashley, Kevin

2015-01-01

The objective of this laboratory study was to identify and measure manganese (Mn) fractions in chamber-generated welding fumes (WF) and to evaluate and compare the results from a sequential extraction procedure for Mn fractions with that of an acid digestion procedure for measurement of total, elemental Mn. To prepare Mn-containing particulate matter from representative welding processes, a welding system was operated in short circuit gas metal arc welding (GMAW) mode using both stainless steel (SS) and mild carbon steel (MCS) and also with flux cored arc welding (FCAW) and shielded metal arc welding (SMAW) using MCS. Generated WF samples were collected onto polycarbonate filters before homogenization, weighing and storage in scintillation vials. The extraction procedure consisted of four sequential steps to measure various Mn fractions based upon selective solubility: (1) soluble Mn dissolved in 0.01 M ammonium acetate; (2) Mn (0,II) dissolved in 25 % (v/v) acetic acid; (3) Mn (III,IV) dissolved in 0.5% (w/v) hydroxylamine hydrochloride in 25% (v/v) acetic acid; and (4) insoluble Mn extracted with concentrated hydrochloric and nitric acids. After sample treatment, the four fractions were analyzed for Mn by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). WF from GMAW and FCAW showed similar distributions of Mn species, with the largest concentrations of Mn detected in the Mn (0,II) and insoluble Mn fractions. On the other hand, the majority of the Mn content of SMAW fume was detected as Mn (III,IV). Although the concentration of Mn measured from summation of the four sequential steps was statistically significantly different from that measured from the hot block dissolution method for total Mn, the difference is small enough to be of no practical importance for industrial hygiene air samples, and either method may be used for Mn measurement. The sequential extraction method provides valuable information about the oxidation state of Mn in samples and allows for comparison to results from previous work and from total Mn dissolution methods. PMID:26345630

Manganese speciation of laboratory-generated welding fumes.

PubMed

Andrews, Ronnee N; Keane, Michael; Hanley, Kevin W; Feng, H Amy; Ashley, Kevin

The objective of this laboratory study was to identify and measure manganese (Mn) fractions in chamber-generated welding fumes (WF) and to evaluate and compare the results from a sequential extraction procedure for Mn fractions with that of an acid digestion procedure for measurement of total, elemental Mn. To prepare Mn-containing particulate matter from representative welding processes, a welding system was operated in short circuit gas metal arc welding (GMAW) mode using both stainless steel (SS) and mild carbon steel (MCS) and also with flux cored arc welding (FCAW) and shielded metal arc welding (SMAW) using MCS. Generated WF samples were collected onto polycarbonate filters before homogenization, weighing and storage in scintillation vials. The extraction procedure consisted of four sequential steps to measure various Mn fractions based upon selective solubility: (1) soluble Mn dissolved in 0.01 M ammonium acetate; (2) Mn (0,II) dissolved in 25 % (v/v) acetic acid; (3) Mn (III,IV) dissolved in 0.5% (w/v) hydroxylamine hydrochloride in 25% (v/v) acetic acid; and (4) insoluble Mn extracted with concentrated hydrochloric and nitric acids. After sample treatment, the four fractions were analyzed for Mn by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). WF from GMAW and FCAW showed similar distributions of Mn species, with the largest concentrations of Mn detected in the Mn (0,II) and insoluble Mn fractions. On the other hand, the majority of the Mn content of SMAW fume was detected as Mn (III,IV). Although the concentration of Mn measured from summation of the four sequential steps was statistically significantly different from that measured from the hot block dissolution method for total Mn, the difference is small enough to be of no practical importance for industrial hygiene air samples, and either method may be used for Mn measurement. The sequential extraction method provides valuable information about the oxidation state of Mn in samples and allows for comparison to results from previous work and from total Mn dissolution methods.

Lifetime, Critical Nucleus Size, and Laplace Pressure of Individual Electrochemically Generated Nanobubbles

NASA Astrophysics Data System (ADS)

German, Sean R.

This dissertation presents experimental and computational studies of individual nanobubbles electrochemically generated at platinum nanoelectrodes. Chapter 1 provides an overview of the physics governing bubble dynamics and a brief summary of the literature regarding nanobubbles. Chapter 2 describes a fast scan voltammetric method for measurement of nanobubble dissolution rates. After a nanobubble is nucleated from gas generated via an electrode reaction, the electrode potential is rapidly stepped to a value where the bubble is unstable and begins to dissolve. The electrode potential is immediately scanned back to values where the bubble was initially stable. Depending on the rate of this second voltammetric scan, the initial bubble may or may not have time to dissolve. The fastest scan rate at which the bubble dissolves is used to determine the bubble's lifetime. The results indicate that dissolution of a H2 or N2 nanobubble is, in part, limited by the transfer of molecules across the gas/water interface. Chapter 3 presents electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of a nanobubble of H 2, N2, or O2 at a Pt nanodisk electrode. The results are analyzed using classical thermodynamic relationships to provide an estimate of the size of the critical gas nucleus that grows into a stable bubble. This critical nucleus size is independent of the radius of the Pt nanodisk employed and weakly dependent on the nature of the gas. Chapter 4 reports electrochemical measurements of Laplace pressures within single H2 bubbles between 7 and 200 nm radius (corresponding, respectively, to between 200 and 7 atmospheres). The current, associated with H2 gas generation, supporting a steady-state nanobubble is modulated by application of external pressure. The slope of the current-pressure response allows extrapolation of the bubble's curvature-dependent internal pressure. The results demonstrate a linear relationship between a bubble's Laplace pressure and its reciprocal radius, verifying the classical thermodynamic description of H2 nanobubbles as small as 10 nm. Chapter 5 summarizes these results and places them in the context of current research. Future directions for further studies are suggested.

Exploring the chemical composition of pelagic tar collected in the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Green, H. S.; Reddy, C. M.; Valentine, D. L.; Aeppli, C.; Swarthout, B.; Sharpless, C.; Joyce, P.; Meyer, A. W.; Fuller, S. A.; Gosselin, K.

2016-12-01

Pelagic tarballs have been linked to multiple sources and their abundances follow notable historical and geographic trends. An overwhelming number of studies point to operational discharges (cargo washing) as the main source of pelagic tar. In a recent review article, Warnock et al. (2015) summarized that the abundance of tar balls has decreased over the last 30 years. The decreasing trend of tarballs has been attributed to the MARPOL 73/78 Annex I legislation, which was created from conventions held in 1973 and again in 1978 to respond to several tanker accidents and other pollution-related inputs. Two of the studies supporting the "MARPOL 73/78 effect" were based on the historical record of tarballs collected in the North Atlantic Ocean by the Sea Education Association (SEA; Woods Hole, MA). To supplement the SEA record, we performed a series of geochemical analyses on 100 of the SEA samples collected from 1988 to 2014. Bulk and gas chromatographic (GC) analyses revealed that the samples were highly variable. For example, the amount of material that could be dissolved in organic solvent but not measured by gas chromatography (referred to as the % GC amenable, a proxy on the distribution of compound classes that compose the tar) ranged from 10 to 80%, although skewed to values less than 40%. Another parameter, based on the GC data, was the perecentage of the resolved relative to the unresolved signal spanned from 0.1 to 1.8. Nine of the sampes would not dissolve in organic solvents and appear to be soot or coal. This study has an operation limitation as we choose to only examine samples > 1 cm (relative to samples smaller than 1mm). Our approach was based on the assumption that these samples were the most unlikely to be weathered and hence retain the genetic features of the initially released tar. While this study does not have the capacity to test confidently the MARPOL 73/78 effect, it does show that pelagic tars are highly variable, which in turn, have different sources.

Geochemical and isotopic determination of deep groundwater contributions and salinity to the shallow groundwater and surface water systems, Mesilla Basin, New Mexico, Texas, and Mexico

NASA Astrophysics Data System (ADS)

Robertson, A.; Carroll, K. C.; Kubicki, C.; Purtshert, R.

2017-12-01

The Mesilla Basin/Conejos-Médanos aquifer system, extending from southern New Mexico to Chihuahua, Mexico, is a priority transboundary aquifer under the 2006 United States­-Mexico Transboundary Aquifer Assessment Act. Declining water levels, deteriorating water quality, and increasing groundwater use by municipal, industrial, and agricultural users on both sides of the international border raise concerns about long-term aquifer sustainability. Relative contributions of present-day and "paleo" recharge to sustainable fresh groundwater yields has not been determined and evidence suggests that a large source of salinity at the distal end of the Mesilla Basin is saline discharge from deep groundwater flow. The magnitude and distribution of those deep saline flow paths are not determined. The contribution of deep groundwater to discharge and salinity in the shallow groundwater and surface water of the Mesilla Basin will be determined by collecting discrete groundwater samples and analyzing for aqueous geochemical and isotopic tracers, as well as the radioisotopes of argon and krypton. Analytes include major ions, trace elements, the stable isotopes of water, strontium and boron isotopes, uranium isotopes, the carbon isotopes of dissolved inorganic carbon, noble gas concentrations and helium isotope ratios. Dissolved gases are extracted and captured from groundwater wells using membrane contactors in a process known as ultra-trace sampling. Gas samples are analyzed for radioisotope ratios of krypton by the ATTA method and argon by low-level counting. Effectiveness of the ultra-trace sampling device and method was evaluated by comparing results of tritium concentrations to the krypton-85 content. Good agreement between the analyses, especially in samples with undetectable tritium, indicates that the ultra-trace procedure is effective and confirms that introduction of atmospheric air has not occurred. The geochemistry data indicate a complex system of geochemical endmembers, and mixing between these endmembers. Ongoing work seeks to better constrain groundwater ages and mixing models through the coupled use of conventional aqueous geochemical and isotopic analysis and the ultra-trace constituents.

Concepts and data-collection techniques used in a study of the unsaturated zone at a low-level radioactive-waste disposal site near Sheffield, Illinois

USGS Publications Warehouse

Healy, R.W.; DeVries, M.P.; Striegl, Robert G.

1986-01-01

A study of water and radionuclide movement through the unsaturated zone is being conducted at the low level radioactive waste disposal site near Sheffield, Illinois. Included in the study are detailed investigations of evapotranspiration, movement of water through waste trench covers, and movement of water and radionuclides (dissolved and gaseous) from the trenches. An energy balance/Bowen ratio approach is used to determine evapotranspiration. Precipitation, net radiation, soil-heat flux, air temperature and water vapor content gradients, wind speed, and wind direction are measured. Soil water tension is measured with tensiometers which are connected to pressure transducers. Meteorological sensors and tensiometers which are connected to pressure transducers. Meteorological sensors and tensiometers are monitored with automatic data loggers. Soil moisture contents are measured through small-diameter access tubes with neutron and gamma-ray attenuation gages. Data beneath the trenches are obtained through a 130-meter-long tunnel which extends under four of the trenches. Water samples are obtained with suction lysimeters, and samples of the geologic material are obtained with core tubes. These samples are analyzed for radiometric and inorganic chemistry. Gas samples are obtained from gas piezometers and analyzed for partial pressures of major constituents, Radon-222, tritiated water vapor, and carbon-14 dioxide. (USGS)

Total Dissolved Gas Effects on Fishes of the Lower Columbia River

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

McGrath, Kathy E.; Dawley, Earl; Geist, David R.

2006-03-31

Gas supersaturation problems generated by spill from dams on the Columbia River were first identified in the 1960s. Since that time, considerable research has been conducted on effects of gas supersaturation on aquatic life, primarily juvenile salmonids. Also since that time, modifications to dam structures and operations have reduced supersaturated gas levels produced by the dams. The limit for total dissolved gas saturation (TDGS) as mandated by current Environmental Protection Agency water quality standards is 110%. State management agencies issue limited waivers to water quality, allowing production of levels of up to 120% TDGS to facilitate the downstream migration ofmore » juvenile salmonids. Recently, gas supersaturation as a water quality issue has resurfaced as concerns have grown regarding chronic effects of spill-related total dissolved gas on salmonids, including incubating embryos and larvae, resident fish species, and other aquatic organisms. Because of current concerns, and because the last comprehensive review of research on supersaturation effects on fishes was conducted in 1997, we reviewed recent supersaturation literature to identify new or ongoing issues that may not be adequately addressed by the current 110% TDGS limit and the 120% TDGS water quality waiver. We found that recent work supports older research indicating that short-term exposure to levels up to 120% TDGS does not produce acute effects on migratory juvenile or adult salmonids when compensating depths are available. Monitoring programs at Snake and Columbia river dams from 1995 to the early 2000s documented a low incidence of significant gas bubble disease or mortality in Columbia River salmonids, resident fishes, or other taxa. We did, however, identify five areas of concern in which total dissolved gas levels lower than water quality limits may produce sublethal effects on fishes of the Columbia River. These areas of concern are 1) sensitive and vulnerable species or life stages, 2) long-term chronic or multiple exposure, 3) vulnerable habitats and reaches, 4) effects on incubating fish in hyporheic habitats, and 5) community and ecosystem effects. Although some of these areas of concern may have been identified previously in earlier works, we suggest that consideration of the issues is warranted to avoid detrimental impacts on aquatic resources of the Columbia River system. We discuss these issues and provide recommendations to regulatory and management agencies based on our review of recent literature. In general, we recommend that additional attention be directed toward resolving the uncertainties within these five areas.« less

Analysis of dissolved organic carbon concentration and 13C isotopic signature by TOC-IRMS - assessment of analytical performance

NASA Astrophysics Data System (ADS)

Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Kalbitz, Karsten

2013-04-01

Stable carbon isotopes provide a powerful tool to assess carbon pools and their dynamics. Dissolved organic carbon (DOC) has been recognized to play an important role in ecosystem functioning and carbon cycling and has therefore gained increased research interest. However, direct measurement of 13C isotopic signature of carbon in the dissolved phase is technically challenging particularly using high temperature combustion. Until recently, mainly custom-made systems existed which were modified for coupling of TOC instruments with IRMS for simultaneous assessment of C content and isotopic signature. The variety of coupled systems showed differences in their analytical performances. For analysis of DOC high temperature combustion is recognized as best performing method, owing to its high efficiency of conversion to CO2 also for highly refractory components (e.g. humic, fulvic acids) present in DOC and soil extracts. Therefore, we tested high temperature combustion TOC coupled to IRMS (developed by Elementar Group) for bulk measurements of DOC concentration and 13C signature. The instruments are coupled via an Interface to exchange the carrier gas from O2 to He and to concentrate the derived CO2 for the isotope measurement. Analytical performance of the system was assessed for a variety of organic compounds characterized by different stability and complexity, including humic acid and DOM. We tested injection volumes between 0.2-3 ml, thereby enabling measurement of broad concentration ranges. With an injection volume of 0.5 ml (n=3, preceded by 1 discarded injection), DOC and 13C signatures for concentrations between 5-150 mg C/L were analyzed with high precision (standard deviation (SD) predominantly <0.1‰), good accuracy and linearity (overall SD <0.9‰). For the same settings, slightly higher variation in precision was observed among the lower concentration range and depending upon specific system conditions. Differences in 13C signatures of about 50‰ among samples did not affect the precision of the analysis of natural abundance and labeled samples. Natural DOM, derived from different soils and assessed at various concentrations, was measured with similar good analytical performance, and also tested for the effect of freezing and re-dissolving. We found good performance of TOC-IRMS in comparison with other systems capable of determining C concentration and isotopic signatures. We recognize the advantages of this system providing: - High sample throughput, short measurement time (15 minutes), flexible sample volume - Easy maintenance, handling, rapid sample preparation (no pretreatment) This preliminary assessment highlights wide-ranging opportunities for further research on concentrations and isotopic signatures by TOC-IRMS to elucidate the role of dissolved carbon in terrestrial and aquatic systems.

Recovery of [CO2]T from Aqueous Bicarbonate using a Gas Permeable Membrane

DTIC Science & Technology

2008-06-25

pores as a function of differential partial gas pressures. Therefore it has been assumed for gas/ liquid systems that only the dissolved carbon dioxide...and pressure [10]. Gas permeable membranes are available commercially for the removal or addition of gases to liquids . Most of these applications...measurements were conducted with a standardized Fisher combination glass electrode. A microporous polypropylene membrane commercially designated as 2400

Derivation and calibration of semi-empirical gas geothermometers for Mahanagdong Geothermal Project, Philippines

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

Sanchez, D.R.

1996-12-31

The dissolved CO{sub 2}, H{sub 2}S, and H{sub 2} gases in Mahanagdong aquifer fluids are controlled by specific gas-mineral equilibria. At temperature range of 250 to 310 {degrees}C, CO{sub 2} is buffered by clinozoisite + K-feldspar + calcite + muscovite (illite) + quartz mineral assemblage. For H{sub 2}S and H{sub 2} dissolved gases, they are more likely buffered by pyrrhotite + pyrite + magnetite mineral assemblage at similar temperature range. Calibration of five Mahanagdong (MG) gas geothermometers is presented, three of which used CO{sub 2}, H{sub 2}S, and H{sub 2} concentration in steam. The remaining two use CO{sub 2}/H{sub 2}more » and H{sub 2}S/H{sub 2} ratios. The calibration is based on the relation between gas content of drillhole discharges and measured aquifer temperatures. After establishing the gas content in the aquifer, gas concentrations were computed in steam after adiabatic boiling to atmospheric condition (100 {degrees}C), to obtain gas geothermometry functions. These functions could also be used in evaluating fraction of steam condensation and temperature of phase separation. A demonstration given the Mahanagdong fumarole data, indicates that there is generally a fair relation between computed temperatures using Mahanagdong gas geothermometers and the actual field trend`s temperatures.« less

Improving the yield from fermentative hydrogen production.

PubMed

Kraemer, Jeremy T; Bagley, David M

2007-05-01

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.

Design, Fabrication, and Shakeout Testing of ATALANTE Dissolver Off-Gas Sorbent-Based Capture System

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

Walker, Jr, Joseph Franklin; Jubin, Robert Thomas; Jordan, Jacob A.

A sorbent-based capture system designed for integration into the existing dissolver off-gas (DOG) treatment system at the ATelier Alpha et Laboratoires pour ANalyses, Transuraniens et Etudes de retraitement (ATALANTE) facility has been successfully designed and fabricated and has undergone shakeout testing. Discussions with personnel from the ATALANTE facility provided guidance that was used for the design. All components for this system were specified, procured, and received on site at Oak Ridge National Laboratory (ORNL). The system was then fabricated and tested at ORNL to verify operation. Shakeout testing resulted in a simplified system. This system should be easily installed intomore » the existing facility and should be straightforward to operate during future experimental testing. All parts were selected to be compatible with ATALANTE power supplies, space requirements, and the existing DOG treatment system. Additionally, the system was demonstrated to meet all of four design requirements. These include (1) a dissolver off-gas flow rate of ≤100 L/h (1.67 L/min), (2) an external temperature of ≤50°C for all system components placed in the hot cell, (3) a sorbent bed temperature of ~150°C, and (4) a gas temperature of ~150°C upon entry into the sorbent bed. The system will be ready for shipment and installation in the existing DOG treatment system at ATALANTE in FY 2016.« less

Geochemical and strontium isotope characterization of produced waters from Marcellus Shale natural gas extraction.

PubMed

Chapman, Elizabeth C; Capo, Rosemary C; Stewart, Brian W; Kirby, Carl S; Hammack, Richard W; Schroeder, Karl T; Edenborn, Harry M

2012-03-20

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 (ε(Sr)(SW) = +13.8 to +41.6, where ε(Sr) (SW) is the deviation of the (87)Sr/(86)Sr ratio from that of seawater in parts per 10(4)); 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.

Nondisruptive Dissolution of Hyperpolarized 129 Xe into Viscous Aqueous and Organic Liquid Crystalline Environments

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

Truxal, Ashley E.; Slack, Clancy C.; Gomes, Muller D.

2016-03-08

Studies of hyperpolarized xenon-129 in media such as liquid crystals and cell suspensions are in demand for applications ranging from biomedical imaging to materials engineering but have been hindered by the inability to bubble Xe through the desired media as a result of viscosity or perturbations caused by bubbles. This research reports on a device that can be reliably used to dissolve hp- 129 Xe into viscous aqueous and organic samples without bubbling. This method is robust, requires small sample volumes ( < 60 μL), is compatible with existing NMR hardware, and is made from readily available materials. Experiments showmore » that Xe can be introduced into viscous and aligned media without disrupting molecular order. We detected dissolved xenon in an aqueous liquid crystal that is disrupted by the shear forces of bubbling, and we observed liquid-crystal phase transitions in (MBBA). This tool allows an entirely new class of samples to be investigated by hyperpolarized-gas NMR spectroscopy. Blending into the crowd: A new device that facilitates the direct dissolution of hyperpolarized 129 Xe into viscous liquid-crystalline media is presented. 129 Xe and 2 H NMR spectra show the nondisruptive dissolution of xenon, the presence of ordered phases, and, in the case of the thermotropic liquid crystal N-(4-methoxybenzylidene)-4-butylaniline, a nematic-isotropic phase transition.« less

Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

DOEpatents

Aines, Roger D.; Bourcier, William L.; Viani, Brian

2013-01-29

A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

Malignant human cell transformation of Marcellus Shale gas drilling flow back water

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

Yao, Yixin; Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987; Chen, Tingting

The rapid development of high-volume horizontal hydraulic fracturing for mining natural gas from shale has posed potential impacts on human health and biodiversity. The produced flow back waters after hydraulic stimulation are known to carry high levels of saline and total dissolved solids. To understand the toxicity and potential carcinogenic effects of these wastewaters, flow back waters from five Marcellus hydraulic fracturing oil and gas wells were analyzed. The physicochemical nature of these samples was analyzed by inductively coupled plasma mass spectrometry and scanning electron microscopy/energy dispersive X-ray spectroscopy. A cytotoxicity study using colony formation as the endpoint was carriedmore » out to define the LC{sub 50} values of test samples using human bronchial epithelial cells (BEAS-2B). The BEAS-2B cell transformation assay was employed to assess the carcinogenic potential of the samples. Barium and strontium were among the most abundant metals in these samples and the same metals were found to be elevated in BEAS-2B cells after long-term treatment. BEAS-2B cells treated for 6 weeks with flow back waters produced colony formation in soft agar that was concentration dependent. In addition, flow back water-transformed BEAS-2B cells show better migration capability when compared to control cells. This study provides information needed to assess the potential health impact of post-hydraulic fracturing flow back waters from Marcellus Shale natural gas mining. - Highlights: • This is the first report of potential cytotoxicity and transforming activity of Marcellus shale gas mining flow back to mammalian cells. • Barium and Strontium were elevated in flow back water exposed cells. • Flow back water malignantly transformed cells and formed tumor in athymic nude mice. • Flow back transformed cells exhibited altered transcriptome with dysregulated cell migration pathway and adherent junction pathway.« less

Solute concentrations influence microbial methanogenesis in coal-bearing strata of the Cherokee basin, USA

DOE PAGES

Kirk, Matthew F.; Wilson, Brien H.; Marquart, Kyle A.; ...

2015-11-18

In this study, microorganisms have contributed significantly to subsurface energy resources by converting organic matter in hydrocarbon reservoirs into methane, the main component of natural gas. In this study, we consider environmental controls on microbial populations in coal-bearing strata of the Cherokee basin, an unconventional natural gas resource in southeast Kansas, USA. Pennsylvanian-age strata in the basin contain numerous thin (0.4–1.1 m) coalbeds with marginal thermal maturities (0.5–0.7% R o) that are interbedded with shale and sandstone. We collected gas, water, and microbe samples from 16 commercial coalbed methane wells for geochemical and microbiological analysis. The water samples were Na–Clmore » type with total dissolved solids (TDS) content ranging from 34.9 to 91.3 g L –1. Gas dryness values [C 1/(C 2 + C 3)] averaged 2640 and carbon and hydrogen isotope ratios of methane differed from those of carbon dioxide and water, respectively, by an average of 65 and 183‰. These values are thought to be consistent with gas that formed primarily by hydrogenotrophic methanogenesis. Results from cultivation assays and taxonomic analysis of 16S rRNA genes agree with the geochemical results. Cultivable methanogens were present in every sample tested, methanogen sequences dominate the archaeal community in each sample (avg 91%), and few archaeal sequences (avg 4.2%) were classified within Methanosarcinales, an order of methanogens known to contain methylotrophic methanogens. Although hydrogenotrophs appear dominant, geochemical and microbial analyses both indicate that the proportion of methane generated by acetoclastic methanogens increases with the solute content of formation water, a trend that is contrary to existing conceptual models. Consistent with this trend, beta diversity analyses show that archaeal diversity significantly correlates with formation water solute content. In contrast, bacterial diversity more strongly correlates with location than solute content, possibly as a result of spatial variation in the thermal maturity of the coalbeds.« less

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

Kirk, Matthew F.; Wilson, Brien H.; Marquart, Kyle A.

In this study, microorganisms have contributed significantly to subsurface energy resources by converting organic matter in hydrocarbon reservoirs into methane, the main component of natural gas. In this study, we consider environmental controls on microbial populations in coal-bearing strata of the Cherokee basin, an unconventional natural gas resource in southeast Kansas, USA. Pennsylvanian-age strata in the basin contain numerous thin (0.4–1.1 m) coalbeds with marginal thermal maturities (0.5–0.7% R o) that are interbedded with shale and sandstone. We collected gas, water, and microbe samples from 16 commercial coalbed methane wells for geochemical and microbiological analysis. The water samples were Na–Clmore » type with total dissolved solids (TDS) content ranging from 34.9 to 91.3 g L –1. Gas dryness values [C 1/(C 2 + C 3)] averaged 2640 and carbon and hydrogen isotope ratios of methane differed from those of carbon dioxide and water, respectively, by an average of 65 and 183‰. These values are thought to be consistent with gas that formed primarily by hydrogenotrophic methanogenesis. Results from cultivation assays and taxonomic analysis of 16S rRNA genes agree with the geochemical results. Cultivable methanogens were present in every sample tested, methanogen sequences dominate the archaeal community in each sample (avg 91%), and few archaeal sequences (avg 4.2%) were classified within Methanosarcinales, an order of methanogens known to contain methylotrophic methanogens. Although hydrogenotrophs appear dominant, geochemical and microbial analyses both indicate that the proportion of methane generated by acetoclastic methanogens increases with the solute content of formation water, a trend that is contrary to existing conceptual models. Consistent with this trend, beta diversity analyses show that archaeal diversity significantly correlates with formation water solute content. In contrast, bacterial diversity more strongly correlates with location than solute content, possibly as a result of spatial variation in the thermal maturity of the coalbeds.« less

Water-Chemistry Data for Selected Springs, Geysers, and Streams in Yellowstone National Park, Wyoming, 2003-2005

USGS Publications Warehouse

Ball, James W.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Holloway, JoAnn M.

2008-01-01

Water analyses are reported for 157 samples collected from numerous hot springs, their overflow drainages, and Lemonade Creek in Yellowstone National Park (YNP) during 2003-2005. Water samples were collected and analyzed for major and trace constituents from ten areas of YNP including Terrace and Beryl Springs in the Gibbon Canyon area, Norris Geyser Basin, the West Nymph Creek thermal area, the area near Nymph Lake, Hazle Lake, and Frying Pan Spring, Lower Geyser Basin, Washburn Hot Springs, Mammoth Hot Springs, Potts Hot Spring Basin, the Sulphur Caldron area, and Lemonade Creek near the Solfatara Trail. These water samples were collected and analyzed as part of research investigations in YNP on arsenic, antimony, and sulfur redox distribution in hot springs and overflow drainages, and the occurrence and distribution of dissolved mercury. Most samples were analyzed for major cations and anions, trace metals, redox species of antimony, arsenic, iron, nitrogen, and sulfur, and isotopes of hydrogen and oxygen. Analyses were performed at the sampling site, in an on-site mobile laboratory vehicle, or later in a U.S. Geological Survey laboratory, depending on stability of the constituent and whether it could be preserved effectively. Water samples were filtered and preserved onsite. Water temperature, specific conductance, pH, Eh (redox potential relative to the Standard Hydrogen Electrode), and dissolved hydrogen sulfide were measured onsite at the time of sampling. Acidity was determined by titration, usually within a few days of sample collection. Alkalinity was determined by titration within 1 to 2 weeks of sample collection. Concentrations of thiosulfate and polythionate were determined as soon as possible (generally minutes to hours after sample collection) by ion chromatography in an on-site mobile laboratory vehicle. Total dissolved-iron and ferrous-iron concentrations often were measured onsite in the mobile laboratory vehicle. Concentrations of dissolved aluminum, arsenic, boron, barium, beryllium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, selenium, silica, strontium, vanadium, and zinc were determined by inductively-coupled plasma-optical emission spectrometry. Trace concentrations of dissolved antimony, cadmium, cobalt, chromium, copper, lead, and selenium were determined by Zeeman-corrected graphite-furnace atomic-absorption spectrometry. Dissolved concentrations of total arsenic, arsenite, total antimony, and antimonite were determined by hydride-generation atomic-absorption spectrometry using a flow-injection analysis system. Dissolved concentrations of total mercury and methyl mercury were determined by cold-vapor atomic-fluorescence spectrometry. Concentrations of dissolved chloride, fluoride, nitrate, bromide, and sulfate were determined by ion chromatography. Concentrations of dissolved ferrous and total iron were determined by the FerroZine colorimetric method. Concentrations of dissolved nitrite were determined by colorimetry or chemiluminescence. Concentrations of dissolved ammonium were determined by ion chromatography, with reanalysis by colorimetry when separation of sodium and ammonia peaks was poor. Dissolved organic carbon concentrations were determined by the wet persulfate oxidation method. Hydrogen and oxygen isotope ratios were determined using the hydrogen and CO2 equilibration techniques, respectively.

Minutes of the Tank Waste Science Panel Meeting March 25--27, 1992. Hanford Tank Safety Project

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

Schutz, W W; Consultant, Wellington, Delaware; Strachan, D M

Discussions from the seventh meeting of the Tank Waste Science are presented in Colorado. The subject areas included the generation of gases in Tank 241-SY-101, the possible use of sonication as a mitigation method, and analysis for organic constituents in core samples. Results presented and discussed include: Ferrocyanides appear to be rapidly dissolved in 1M NaOH; upon standing in the laboratory at ambient conditions oxalate precipitates from simulated wastes containing HEDTA. This suggests that one of the main components in the solids in Tank 241-SY-101 is oxalate; hydrogen evolved from waste samples from Tank 241-SY-101 is five times that observedmore » in the off gas from the tank; data suggest that mitigation of Tank 241-SY-101 will not cause a high release of dissolved N{sub 2}O; when using a slurry for radiation studies, a portion of the generated gases is very difficult to remove. To totally recover the generated gases, the solids must first be dissolved. This result may have an impact on mitigation by mixing if the gases are not released. Using {sup 13}C-labeled organics in thermal degradation studies has allowed researchers to illucidate much of the kinetic mechanism for the degradation of HEDTA and glycolate. In addition to some of the intermediate, more complex organic species, oxalate, formate, and CO{sub 2} were identified; and analytic methods for organics in radioactive complex solutions such as that found in Tank 241-SY-101 have been developed and others continue to be developed.« less

Microcrystalline sphalerite in resin globules suspended in Lake Kivu, East Africa

USGS Publications Warehouse

Degens, E.T.; Okada, H.; Honjo, S.; Hathaway, J.C.

1972-01-01

The origin and chemical nature of micron-sized spheres found as suspended particles in Lake Kivu are examined. It can be shown that the hollow spheres, with a wall thickness of 500 A??, consist of a complex polymeric resinous material which has little functionality, except for hydroxyl groups. The spheres arise in the process of degassing of water samples at depth. Tiny gas bubbles, about 1 micron in size, act as scavengers of dissolved resinous material. The newly created resinous membrane promotes the selective coordination of zinc dissolved in the water column. In the prevailing H2S regime, formation of sphalerite crystals in induced. The size range of the crystals, 5 to 50 A??, corresponds to 1 to 10 unit cells and suggests that the resinous membrane also acts as a template in sphalerite growth processes. The sources of the zinc and dissolved gases (CO2, CH4, H2S) are hydrothermal springs seeping from the lake bottom into the basin. Water discharge is substantial; about 100 years are required to fill the lake to its present level (ca. 550 km3 water). The average Kivu water contains 2 ppm zinc. Thus, 1 million tons of zinc are contained in Lake Kivu in the form of sphalerite. ?? 1972 Springer-Verlag.

Effect of Bubbles and Silica Dissolution on Melter Feed Rheology during Conversion to Glass

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

Marcial, Jose; Chun, Jaehun; Hrma, Pavel R.

As the nuclear waste glass melter feed is converted to molten glass, the feed becomes a continuous glass-forming melt where dissolving refractory constituents are suspended together with numerous gas bubbles. Knowledge of mechanical properties of the reacting melter feed is crucial for understanding the feed-to-glass conversion as it occurs during melting. We studied the melter feed viscosity during heating and correlated it with volume fractions of dissolving quartz particles and gas phase. The measurements were performed with a rotating spindle rheometer on the melter feed heated at 5 K/min, starting at several different temperatures. The effects of undissolved quartz particles,more » gas bubbles, and compositional inhomogeneity on the melter feed viscosity were determined by fitting a linear relationship between log viscosity and volume fractions of suspended phases.« less

Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

NASA Astrophysics Data System (ADS)

Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

2015-12-01

Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

Experimental and simulation studies of iron oxides for geochemical fixation of CO2-SO2 gas mixtures

USGS Publications Warehouse

Garcia, Susana; Rosenbauer, Robert J.; Palandri, James; Maroto-Valer, M. Mercedes

2011-01-01

Iron-bearing minerals are reactive phases of the subsurface environment and could potentially trap CO2–SO2gas mixtures derived from fossil fuel combustion processes by their conversion to siderite (FeCO3) and dissolved sulfate. Changes in fluid and mineral compositions resulting from reactions, involving the co-injection of SO2 with CO2 were observed both theoretically and experimentally. Experiments were conducted with a natural hematite (α-Fe2O3) sample. A high pressure-high temperature apparatus was used to simulate conditions in geologic formations deeper than 800 m, where CO2 is in the supercritical state. Solid samples were allowed to react with a NaCl–NaOH brine and SO2-bearing CO2-dominated gas mixtures. The predicted equilibrium mineral assemblage at 100 °C and 250 bar became hematite, dawsonite (NaAl(OH)2CO3), siderite (FeCO3) and quartz (SiO2). Experimentally, siderite and dawsonite, derived from the presence of kaolinite (Al2Si2O5(OH)4) in the parent material, were present in residual solids at longer reaction time intervals, which agreed well with results from the modelling work.

Biological groundwater denitrification systems: Lab-scale trials aimed at nitrous oxide production and emission assessment.

PubMed

Capodici, Marco; Avona, Alessia; Laudicina, Vito Armando; Viviani, Gaspare

2018-07-15

Bio-trenches are a sustainable option for treating nitrate contamination in groundwater. However, a possible side effect of this technology is the production of nitrous oxide, a greenhouse gas that can be found both dissolved in the liquid effluent as well as emitted as off gas. The aim of this study was to analyze NO 3 - removal and N 2 O production in lab-scale column trials. The column contained olive nut as organic carbon media. The experimental study was divided into three phases (I, II and III) each characterized by different inlet NO 3 - concentrations (30, 50, 75mgNO 3 -NL -1 respectively). Sampling ports deployed along the length of the column allowed to observe the denitrification process as well as the formation and consumption of intermediate products, such as nitrite (NO 2 - ) and nitrous oxide (N 2 O). In particular, it was observed that N 2 O production represent only a small fraction of removed NO 3 - during Phase I and II, both for dissolved (0.007%) and emitted (0.003%) phase, and it was recorded a high denitrification efficiency, over 99%. Nevertheless, significantly higher values were recorded for Phase 3 concerning emitted phase (0.018%). This fact is due to increased inlet concentration which resulted in a carbon limitation and in a consequent decrease in denitrification efficiency (76%). Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of tributyltin in whole water matrices under the European Water Framework Directive.

PubMed

Richter, Janine; Fettig, Ina; Philipp, Rosemarie; Jakubowski, Norbert; Panne, Ulrich; Fisicaro, Paola; Alasonati, Enrica

2016-08-12

Monitoring of water quality is important to control water pollution. Contamination of the aquatic system has a large effect on human health and the environment. Under the European Water Framework Directive (WFD) 2000/60/EC and the related directive on environmental quality standards (EQS) in the field of water policy 2008/105/EC, the need for sensitive reference methods was highlighted. Since tributyltin (TBT) is one of the WFD listed priority substances a method was developed which is capable to qualify and quantify the pollutant at the required low WFD EQS of 0.2ngL(-1) in whole water bodies, i.e. in non-filtered water samples with dissolved organic carbon and suspended particulate matter. Therefore special attention was paid on the interaction of TBT with the suspended particulate matter and humic substances to obtain a complete representation of the pollution in surface waters. Different water samples were investigated varying the content of organic dissolved and suspended matter. Quantification was performed using species-specific isotope dilution (SSID) and gas chromatography with inductively coupled plasma mass spectrometry (GC-ICP-MS). Different sample treatment strategies were evaluated and compared. The process of internal standard addition was investigated and optimized, hence the equilibrium between internal standards and matrix is of primary importance to perform accurate SSID. Samples spiked at EQS level were analyzed with a recovery between 95 and 105 %. Additionally real surface water samples were investigated and the TBT concentration for the whole water body was determined and compared with conventional routine analysis method. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling Total Dissolved Gas for Optimal Operation of Multireservoir Systems

DOE PAGES

Politano, Marcela; Castro, Alejandro; Hadjerioua, Boualem

2017-02-09

One important environmental issue of hydropower in the Columbia and Snake River Basins (Pacific Northwest region of United States) is elevated total dissolved gas (TDG) downstream of a dam, which has the potential to cause gas bubble disease in affected fish. Gas supersaturation in the Columbia River Basin primarily occurs due to dissolution of bubbles entrained during spill events. This paper presents a physically based TDG model that can be used to optimize spill operations in multireservoir hydropower systems. Independent variables of the model are forebay TDG, tailwater elevation, spillway and powerhouse discharges, project head, and environmental parameters such asmore » temperature and atmospheric pressure. The model contains seven physically meaningful experimental parameters, which were calibrated and validated against TDG data collected downstream of Rock Island Dam (Washington) from 2008 to 2012. In conclusion, a sensitivity analysis was performed to increase the understanding of the relationships between TDG downstream of the dam and processes such as air entrainment, lateral powerhouse flow, and dissolution.« less

Method for making one-container rigid foam

DOEpatents

Aubert, James H.

2005-04-12

A method of making a one-container foam by dissolving a polymer in liquified gas at a pressure greater than the vapor pressure of the liquified gas and than rapidly decreasing the pressure within approximately 60 seconds to foam a foam. The foam can be rigid and also have adhesive properties. The liquified gas used is CF₃ l or mixtures thereof.

Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain.

PubMed

Boehrer, Bertram; Yusta, Iñaki; Magin, Katrin; Sanchez-España, Javier

2016-09-01

High gas charges in deep waters of lakes can represent a hazard to the lives of human beings and animals in the surrounding. As this danger was feared, we quantified the amount of dissolved gas in Guadiana pit lake (Las Herrerías, Huelva; southwest Spain) and documented the temporal evolution over a period of two years. Gas pressure due to dissolved gases, such as carbon dioxide, methane and nitrogen was measured. Based on these data, we assessed the risk and the associated danger of limnic eruptions from the lake and concluded that the present situation cannot be considered safe. By deploying a vertical pipe, the updraft of degassing water was tested and demonstrated: the pilot plant provided enough energy to drive a self-sustained flow. Such a system could be implemented to remove the extreme gas pressure from the deep water. Measurements of discharges could be extrapolated to indicate the size for an efficient plant for the gas removal. The construction of such a system would be technically and economically viable. A reintroduction of degassed water into the monimolimnion would be advisable. Copyright © 2016 Elsevier B.V. All rights reserved.

Mercury in the Black Sea - results of the 2013 GEOTRACES MEDBlack cruise

NASA Astrophysics Data System (ADS)

Heimbürger, L. E.; Sonke, J.; Rijkenberg, M. J. A.; Gerringa, L. J.; De Baar, H. J. W.

2014-12-01

Inorganic mercury (Hg), whether of natural or anthropogenic origin, can be converted into the neurotoxin methylmercury (MeHg). Today we believe this conversion occurs during the bacterial remineralization of sinking organic matter in the oceanic water column. The Black Sea with its high organic matter inputs and anoxic deep waters is an excellent study site to investigate in more detail the processes yielding MeHg. To date only one vertical profile of Hg species near the Western shelf and one vertical profile in the Western Gyre are published (Lamborg et al. 2008). We will present new results of the 2013 Dutch-led GEOTRACES MEDBlack cruise in the Black Sea. Research vessel "Pelagia" occupied 12 full depth stations along an east-west transect from 13 to 25 July 2013. High resolution vertical profiles were sampled using a titanium ultraclean CTD frame (de Baar et al., 2008) equipped with 24 x 24L PVDF samplers. Samples were filtered (0.2µm, Sartobran 300), drawn into pre-cleaned 250mL Savillex PFA bottles and acidified to 0.4% (v:v) with double-distilled HCl. Dissolved MeHg, as the sum of monomethylHg and dimethylHg, was analyzed via isotope dilution gas chromatography sector field inductively coupled mass spectrometry. Total dissolved Hg was determined following the US EPA 1631 method. We will present high resolution vertical Hg species profiles, including one ultra-high resolution profile (1 sample every 5m-depth) to understand the dynamics along the chemocline (Luther et al., 1991). We will also present the results of the GEOTRACES international intercalibration exercise for dissolved MeHg and dissolved total Hg in surface seawater that we organized during the same cruise. References De Baar HJW, Timmermans KR, Laan P, De Porto HH, Ober S, Blom JJ, Bakker MC, Schilling J, Sarthou G, Smit MG, Klunder M. Titan: A new facility for ultraclean sampling of trace elements and isotopes in the deep oceans in the international Geotraces program. Mar. Chem. 2008, 111(1-2): 4-21. Lamborg CH, Yiğiterhan O, Fitzgerald WF, Balcom PH, Hammerschmidt CR, Murray J.Vertical distribution of mercury species at two sites in the Western Black Sea. Mar.Chem. 2008, 111(1-2): 77-89. Luther III GW, Church TM, Powell D. Sulfur speciation and sulfide oxidation in the water column of the Black Sea. DSR I 1991, 38:1121-1137.

Comparison of ultrasonic and thermospray systems for high performance sample introduction to inductively coupled plasma atomic emission spectrometry

NASA Astrophysics Data System (ADS)

Conver, Timothy S.; Koropchak, John A.

1995-06-01

This paper describes detailed work done in our lab to compare analytical figures of merit for pneumatic, ultrasonic and thermospray sample introduction (SI) systems with three different inductively coupled plasma-atomic emission spectrometry (ICP-AES) instruments. One instrument from Leeman Labs, Inc. has an air path echelle spectrometer and a 27 MHz ICP. For low dissolved solid samples with this instrument, we observed that the ultrasonic nebulizer (USN) and fused silica aperture thermospray (FSApT) both offered similar LOD improvements as compared to pneumatic nebulization (PN), 14 and 16 times, respectively. Average sensitivities compared to PN were better for the USN, by 58 times, compared to 39 times for the FSApT. For solutions containing high dissolved solids we observed that FSApT optimized at the same conditions as for low dissolved solids, whereas USN required changes in power and gas flows to maintain a stable discharge. These changes degraded the LODs for USN substantially as compared to those utilized for low dissolved solid solutions, limiting improvement compared to PN to an average factor of 4. In general, sensitivities for USN were degraded at these new conditions. When solutions with 3000 μg/g Ca were analyzed, LOD improvements were smaller for FSApT and USN, but FSApT showed an improvement over USN of 6.5 times. Sensitivities compared to solutions without high dissolved solids were degraded by 19% on average for FSApT, while those for USN were degraded by 26%. The SI systems were also tested with a Varian Instruments Liberty 220 having a vacuum path Czerny-Turner monochromator and a 40 MHz generator. The sensitivities with low dissolved solids solutions compared to PN were 20 times better for the USN and 39 times better for FSApT, and LODs for every element were better for FSApT. Better correlation between relative sensitivities and anticipated relative analyte mass fluxes for FSApT and USN was observed with the Varian instrument. LOD improvements averaged 18 times lower than PN with FSApT while with USN values averaged 8 times lower. When solutions with high dissolved solids were studied it was found that FSApT still offered 5.5 times better LODs than PN and USN offered 4.6 times better LODs than PN. Sensitivities for FSApT averaged 20 times better, while those for USN were 13 times better compared to PN. Finally, background RSDs on the Varian system were generally higher for FSApT than for the USN for similar sample types. A third instrument used for a small set of elements was a Perkin-Elmer model 5500 ICP-AES. This system has a 27 MHz generator with a N 2 purged Czerny-Turner monochromator. LOD trends, background RSDs, and sensitivities were similar to those with the Leeman instrument. However, matrix effects more closely resembled those seen with the Varian instrument for both SI systems. To compare performance and recoveries on a real sample, a National Institute of Standards and Technology, Standard Reference Material 1643c trace elements in water, was analyzed using the Varian system and it was found that both SI systems offered similar recoveries.

ROLE OF THE PHOTO-FENTON REACTION IN THE PRODUCTION OF HYDROXYL RADICALS AND PHOTOBLEACHING OF COLORED DISSOLVED ORGANIC MATTER IN A COASTAL RIVER OF THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

Photochemical reactions involving colored dissolved organic matter (CDOM) in natural waters are important determinants of nutrient cycling, trace gas production and control of light penetration into the water column. In this study the role of the hydroxyl radical ((OH)-O-.) in CD...

Geochemistry of dissolved gases in the hypersaline Orca basin. Technical report

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

Wiesenburg, D.A.

1980-12-01

Hypersaline, anoxic waters significantly affect the biogeochemistry of dissolved gases in the Orca Basin (Northern Gulf of Mexico). The high stability of the Orca brine pool makes it an ideal laboratory for studying production and consumption of dissolved gases during anaerobic decomposition. Depth distributions were determined for nitrogen, oxygen, argon, methane, ethane, propane, ammonia, hydrogen sulfide, and nitrous oxide. Physical stratification of the water column strongly influences Orca Basin gas distributions. The high salinity brine (approx. 250%) is internally well mixed due to convective overturning, but transfer across the brine-sea water interface is controlled by molecular diffusion. With a molecularmore » diffusivity of 0.00001 sq cm/sec, it will take 1,000,000 years for all salts to diffuse from the basin. Heat diffuses faster than salt and is lost from the basin at a rate of 0.5 microcal sq cm/sec. If geothermal heat input from the sediments is slightly higher, this input could account for the higher temperature in the brine (5.6C) compared to the deep Gulf waters (4.2 C). This study has shown the utility of dissolved gases in examining water chemistry of unusual areas. Since sources of dissolved gases are independent of the sources of major ions in solution, calculations of gas distributions on a salt-free basis are useful in examining production and consumption processes.« less

Assessing the hydraulic connection between fresh water aquifers and unconventional gas production using methane and stable isotopes

NASA Astrophysics Data System (ADS)

Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

2015-04-01

Unconventional gas developments pose a risk to groundwater quality and quantity in adjacent or overlying aquifers. To manage these risks there is a need to measure the background concentration of indicator groundwater chemicals and to map pathways of hydraulic connectivity between aquifers. This study presents methane (CH4) concentration and isotopic composition, dissolved organic carbon concentration ([DOC]) and tritium (3H) activity data from an area of expanding coal seam gas (CSG) exploration and production (Condamine Catchment, south-east Queensland, Australia). The target formation for gas production within the Condamine Catchment is the Walloon Coal Measures (WCM). This is a 700 m thick, low-rank CSG resource, which consists of numerous thin discontinuous lenses of coal separated by very fine-to medium-grained sandstone, siltstone, and mudstone, with minor calcareous sandstone, impure limestone and ironstone. The thickness of the coal makes up less than 10% of the total thickness of the unit. The WCM are overlain by sandstone formations, which form part of the Great Artesian Basin (GAB). The Condamine Alluvium fills a paleo-valley carved through the above formations. A combination of groundwater and degassing air samples were collected from irrigation bores and government groundwater monitoring boreholes. Degassing air samples were collected using an SKC 222-2301 air pump, which pumped the gas into 3 L Tedlar bags. The groundwater was analysed for 3H and [DOC]. A mobile CH4 survey was undertaken to continuously sample air in and around areas of agricultural and unconventional gas production. The isotopic signature of gas from the WCM was determined by sampling gas that was off-gassing from a co-produced water holding pond as it was the largest emission that could be directly linked to the WCM. This was used to determine the source signature of the CH4 from the WCM. We used Keeling plots to identify the source signature of the gas sampled. For the borehole samples these plots assume that there are only two sources of CH4, each with a unique isotopic signature. When the two sources mix in varying proportions they will plot along a straight line in the Keeling plot. Geometric mean displacement was used to fit a regression line and determine the intercept value. Within the Keeling plot, samples clustered according to their 3H and [DOC] values. One cluster is associated with near surface biological processes, while the other cluster can be attributed to gas sourced from the WCM. This indicates that in places there is hydraulic connectivity between the WCM and the overlying Condamine Alluvium. The results from this case study demonstrate that measuring 3H activity, [DOC] and CH4 concentrations in combination with CH4 isotopic analysis can provide an early indicator of hydraulic connectivity in areas of expanding unconventional gas development.

Retail promotions and perceptions of R.J. Reynolds' novel dissolvable tobacco in a US test market

PubMed Central

2011-01-01

Background With declining cigarette sales, tobacco manufacturers have been developing and marketing new smokeless products, such as R. J. Reynolds' dissolvable tobacco, Camel Sticks, Strips and Orbs. This study assessed the availability, price and point-of-purchase promotional strategies for Camel Dissolvables, and investigated consumer awareness, interest and perception of these products in the Indiana test market. Methods An exploratory retail audit of point-of-purchase promotions was conducted in a random sample of retailers from 6 store categories (n = 81) in the test market area. Data included: store type, location, product placement, forms/flavors carried, price, types and locations of advertisements and promotions, and ad messages. An Awareness-Attitude-Usage (AAU) survey was used to gauge consumer awareness and knowledge of tobacco products including Camel Dissolvables. Respondents were shown promotional materials from a package onsert and perceptions and interest in the Camel Dissolvables were assessed. An Intended Target Survey (ITS) compared subjects' perceptions of ad targets for several non-tobacco products, as well as Camel Snus, Camel No. 9 and Camel Dissolvables. Respondents were asked to identify each ad's intended target category, perceived targetedness, and purchase intent. Results The products were carried by 46% of stores, most frequently gas stations (100%) and convenience stores (75%). They were shelved near smokeless tobacco (70%), cigarettes (25%) or candy (5%). Prices ranged from $3.59 -$4.19 per package; most stores carried at least 1 promotional item. Ad messages included: "Dissolvable Tobacco" (60%). "Free Trial" (24%), "Special Price" (24%), "What's Your Style?" (22%). At 14% of stores, free trial packs of Camel Dissolvables were offered with another Camel purchase. Awareness was reported by 42% of respondents (n = 243), and trial by 3%. Consumer interest was very low, but younger respondents (< 40 years) were more familiar with Camel Dissolvables (60% vs. 45% for those > 40 years, p < .01). Males, as well as current and former smokers had higher rates of interest and trial; only 1% of never smokers reported trial. In the ITS, only for the 3 tobacco product ads, was perceived targetedness for smokers significantly higher than for non-smokers. Smokers and nonsmokers perceived that the ads targeted smokers. Conclusions Current retail promotional strategies for Camel Sticks, Strips & Orbs appear to be targeting a select audience, primarily current smokers. Overall, consumer awareness, interest and trial were low. PMID:21569637

Retail promotions and perceptions of R.J. Reynolds' novel dissolvable tobacco in a US test market.

PubMed

Romito, Laura M; Saxton, M Kim; Coan, Lorinda L; Christen, Arden G

2011-05-15

With declining cigarette sales, tobacco manufacturers have been developing and marketing new smokeless products, such as R. J. Reynolds' dissolvable tobacco, Camel Sticks, Strips and Orbs. This study assessed the availability, price and point-of-purchase promotional strategies for Camel Dissolvables, and investigated consumer awareness, interest and perception of these products in the Indiana test market. An exploratory retail audit of point-of-purchase promotions was conducted in a random sample of retailers from 6 store categories (n = 81) in the test market area. Data included: store type, location, product placement, forms/flavors carried, price, types and locations of advertisements and promotions, and ad messages. An Awareness-Attitude-Usage (AAU) survey was used to gauge consumer awareness and knowledge of tobacco products including Camel Dissolvables. Respondents were shown promotional materials from a package onsert and perceptions and interest in the Camel Dissolvables were assessed. An Intended Target Survey (ITS) compared subjects' perceptions of ad targets for several non-tobacco products, as well as Camel Snus, Camel No. 9 and Camel Dissolvables. Respondents were asked to identify each ad's intended target category, perceived targetedness, and purchase intent. The products were carried by 46% of stores, most frequently gas stations (100%) and convenience stores (75%). They were shelved near smokeless tobacco (70%), cigarettes (25%) or candy (5%). Prices ranged from $3.59 -$4.19 per package; most stores carried at least 1 promotional item. Ad messages included: "Dissolvable Tobacco" (60%). "Free Trial" (24%), "Special Price" (24%), "What's Your Style?" (22%). At 14% of stores, free trial packs of Camel Dissolvables were offered with another Camel purchase. Awareness was reported by 42% of respondents (n = 243), and trial by 3%. Consumer interest was very low, but younger respondents (< 40 years) were more familiar with Camel Dissolvables (60% vs. 45% for those > 40 years, p < .01). Males, as well as current and former smokers had higher rates of interest and trial; only 1% of never smokers reported trial. In the ITS, only for the 3 tobacco product ads, was perceived targetedness for smokers significantly higher than for non-smokers. Smokers and nonsmokers perceived that the ads targeted smokers. Current retail promotional strategies for Camel Sticks, Strips & Orbs appear to be targeting a select audience, primarily current smokers. Overall, consumer awareness, interest and trial were low.

Effect of oxidation on transport properties of zirconium-1% niobium alloy

NASA Astrophysics Data System (ADS)

Peletsky, V. E.; Musayeva, Z. A.

1995-11-01

The thermal conductivity and electrical resistivity of zirconium-1 wt% niobium samples were measured before and after the process of their oxidation in air. A special procedure was used to dissolve the gas and to smooth out its concentration in the alloy. The basic experiments were performed under high vacuum under steady-state temperature conditions. The temperature range was 300 1600 K. for the pure alloy and 300 1100 K for the samples containing oxygen. It was found that the thermal conductivity—oxygen concentration relation reverses its sign from negative at low and middle temperatures to positive at temperatures above 900 K. The relation between the electrical resistivity and the oxygen content does not show this feature. The Lorenz function was found to have an anomalous temperature dependence.

Quality of ground water in the Columbia Basin, Washington, 1983

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

Turney, G.L.

1986-01-01

Groundwater from 188 sites in the Columbia Basin of central Washington was sampled and analyzed in 1983 for pH, specific conductance, and concentrations of fecal coliform bacteria, major dissolved ions, and dissolved iron, manganese, and nitrate. Twenty of the samples were also analyzed for concentrations of dissolved trace metals including aluminum, arsenic, barium, cadmium, chromium, copper, lead, mercury, selenium, silver, and zinc. The predominant water types were sodium bicarbonate and calcium bicarbonate. The sodium bicarbonate water samples had higher pH, fluoride, and sodium:adsorption ratio values than samples with other water types. Most trace metal concentrations were also < 10 ug/Lmore » except for barium and zinc, which had maximum concentrations of 170 and 600 ug/L, respectively. Nitrate concentrations were < 1.0 mg/L in water from more than half the wells sampled. US EPA (Environmental Protection Agency) drinking water regulations were exceeded in several samples, most commonly involving pH and concentrations of fluoride, nitrate, and dissolved solids in samples from Adams and Grant Counties. Generally, the historical data lead to similar conclusions about the quality of groundwater in the Columbia Basin region. However, historical samples had higher dissolved solids concentrations in Douglas County. Historical samples also included fewer sodium bicarbonate type waters in the region as a whole than the 1983 samples. 24 refs., 2 figs., 4 tabs.« less

Spatial variability in groundwater N2 and N2O in the San Joaquin River

NASA Astrophysics Data System (ADS)

Hinshaw, S.; Dahlgren, R. A.

2010-12-01

The San Joaquin River is surrounded by nearly 2 million acres of irrigated agricultural land. Groundwater inputs from agricultural areas can have severe negative effects on water quality with high nitrate concentrations being a major concern. Riparian zones are important ecological habitats that mitigate nitrogen loading from groundwater discharging into rivers primarily by denitrification. Denitrification is a permanent removal of nitrate by anaerobic microbial communities via the reduction to NO, N2O and N2. However, previous studies have shown that these areas can be source of N2O emissions. Although removal of nitrate through denitrification is advantageous from a water quality perspective, N2O is a harmful greenhouse gas. This study aimed to investigate nitrogen dynamics and dissolved N gases in surface and groundwater of the riparian zones of the San Joaquin River. Excess N2 and N2O concentrations were measured in surface and groundwater at 4 locations along a 33 km reach of the river. Samples were collected within bank sediments and 5 transect points across the river at depth intervals between 2-3 cm and 150 cm. Dissolved N2 and Ar were measured by membrane inlet mass spectrometry and used to estimate excess dissolved N2 concentrations. Dissolved N2O concentrations were measured using the headspace equilibrium technique and analyzed with a gas chromatograph. Both N2 uptake and excess N2 were present, ranging from -3.40 to 8.65 N2 mg/L with a median concentration of 1.20 N2 mg/L. Significantly lower concentrations of N2O were present ranging from 0.0 to 0.12 N2O mg/L. Deeper groundwater sites had significantly higher N2 and N2O concentrations coinciding with decreased O2. The presence of excess N2 and low N2O concentrations documents the importance of denitrification in removing nitrate from groundwater. Further investigation will examine N2O emissions from riparian soils and benthic sediments using static chambers and focus on nitrogen pathways that contribute to high ammonium concentrations with increasing depth.

Water-Quality Data Collected from Vallecito Reservoir, Its Inflows and Outflow, Southwestern Colorado, 1999-2002

USGS Publications Warehouse

Ranalli, Anthony J.

2008-01-01

The Pine River Watershed Stakeholders Group was created in December 1997 to allow local participation in addressing water-quality issues in Los Pi?os River watershed, including Vallecito Reservoir in southwestern Colorado. One water-quality issue identified by the stakeholder group is to increase the understanding of the current water quality of Vallecito Reservoir, its two major inflows, and its outflow. The U.S. Geological Survey (USGS), in cooperation with volunteers from the Pine River Watershed Stakeholders Group and the U.S. Environmental Protection Agency (USEPA), U.S. Bureau of Reclamation (BOR), Colorado Department of Public Health and Environment (CDPHE), Pine River Irrigation District, Southern Ute Tribe, San Juan Basin Health Department, and San Juan Resource Conservation and Development, collected water-quality samples from Vallecito Reservoir, its two major inflows, and its outflow between August 1999 and November 2002 at about monthly intervals from April through November. The water-quality samples were analyzed for total and dissolved metals (aluminum, arsenic, cadmium, copper, chromium, iron, lead, manganese, mercury, nickel, silver, and zinc), dissolved major ions (calcium, magnesium, sodium, potassium, chloride, bicarbonate, and sulfate), dissolved silica, dissolved organic carbon (DOC), ultraviolet (UV) absorbance at 254 and 280 nanometers, nutrients (total organic nitrogen, dissolved organic nitrogen, dissolved ammonia, dissolved nitrate, total phosphorus, dissolved phosphorus, and orthophosphate), chlorophyll-a (reservoir only), and suspended sediment (inlets to the reservoir only). Measurements of field properties (pH, specific conductance, water temperature, and dissolved oxygen) were also made at each sampling site each time a water-quality sample was collected. This report documents (1) sampling sites and times of sample collection, (2) sample-collection methods, (3) laboratory analytical methods, and (4) responsibilities of each agency/group involved in the project. The report also provides the environmental and quality-control data collected during the project and provides an interpretation of the quality-control data (field blanks and field duplicates) to assess the quality of the environmental data. This report provides a baseline data set against which future changes in water quality can be assessed.

Pulsating potentiometric titration technique for assay of dissolved oxygen in water at trace level.

PubMed

Sahoo, P; Ananthanarayanan, R; Malathi, N; Rajiniganth, M P; Murali, N; Swaminathan, P

2010-06-11

A simple but high performance potentiometric titration technique using pulsating sensors has been developed for assay of dissolved oxygen (DO) in water samples down to 10.0 microg L(-1) levels. The technique involves Winkler titration chemistry, commonly used for determination of dissolved oxygen in water at mg L(-1) levels, with modification in methodology for accurate detection of end point even at 10.0 microg L(-1) levels DO present in the sample. An indigenously built sampling cum pretreatment vessel has been deployed for collection and chemical fixing of dissolved oxygen in water samples from flowing water line without exposure to air. A potentiometric titration facility using pulsating sensors developed in-house is used to carry out titration. The power of the titration technique has been realised in estimation of very dilute solution of iodine equivalent to 10 microg L(-1) O(2). Finally, several water samples containing dissolved oxygen from mg L(-1) to microg L(-1) levels were successfully analysed with excellent reproducibility using this new technique. The precision in measurement of DO in water at 10 microg L(-1) O(2) level is 0.14 (n=5), RSD: 1.4%. Probably for the first time a potentiometric titration technique has been successfully deployed for assay of dissolved oxygen in water samples at 10 microg L(-1) levels. Copyright 2010 Elsevier B.V. All rights reserved.

Determination of low (137)Cs concentration in seawater using ammonium 12-molybdophosphate adsorption and chemical separation method.

PubMed

Park, J H; Chang, B U; Kim, Y J; Seo, J S; Choi, S W; Yun, J Y

2008-12-01

A new method has been developed for analyzing (137)Cs in a small volume of seawater. Ammonium 12-molybdophosphate (AMP) was used two times during pretreatment procedure. The first step was to adsorb (137)Cs in seawater samples into AMP in order to reduce sample volume, and the second was to remove (87)Rb, interference nuclide for beta counting. The AMP adsorbing (137)Cs was dissolved by sodium hydroxide solution, and then (137)Cs was finally formed to be cesium chloroplatinate precipitate by adding 10% hexachloroplatinic acid. The beta rays emitted from (137)Cs were measured with a low background gas-proportional alpha/beta counter. This method was applied to several seawater samples taken in the East Sea of Korea. Compared to the routinely used gamma-spectrometry method, this new AMP method was reliable and suitable for analyzing (137)Cs in deep seawater.

Groundwater noble gas, age, and temperature signatures in an Alpine watershed: Valuable tools in conceptual model development

USGS Publications Warehouse

Manning, Andrew H.; Caine, Jonathan S.

2007-01-01

Bedrock groundwater in alpine watersheds is poorly understood, mainly because of a scarcity of wells in alpine settings. Groundwater noble gas, age, and temperature data were collected from springs and wells with depths of 3–342 m in Handcart Gulch, an alpine watershed in Colorado. Temperature profiles indicate active groundwater circulation to a maximum depth (aquifer thickness) of about 200 m, or about 150 m below the water table. Dissolved noble gas data show unusually high excess air concentrations (>0.02 cm3 STP/g, ΔNe > 170%) in the bedrock, consistent with unusually large seasonal water table fluctuations (up to 50 m) observed in the upper part of the watershed. Apparent 3H/3He ages are positively correlated with sample depth and excess air concentrations. Integrated samples were collected from artesian bedrock wells near the trunk stream and are assumed to approximate flow‐weighted samples reflecting bedrock aquifer mean residence times. Exponential mean ages for these integrated samples are remarkably consistent along the stream, four of five being from 8 to 11 years. The tracer data in combination with other hydrologic and geologic data support a relatively simple conceptual model of groundwater flow in the watershed in which (1) permeability is primarily a function of depth; (2) water table fluctuations increase with distance from the stream; and (3) recharge, aquifer thickness, and porosity are relatively uniform throughout the watershed in spite of the geological complexity of the Proterozoic crystalline rocks that underlie it.

A Simplified Method for Sampling and Analysis of High Volume Surface Water for Organic Contaminants Using XAD-2

USGS Publications Warehouse

Datta, S.; Do, L.V.; Young, T.M.

2004-01-01

A simple compressed-gas driven system for field processing and extracting water for subsequent analyses of hydrophobic organic compounds is presented. The pumping device is a pneumatically driven pump and filtration system that can easily clarify at 4L/min. The extraction device uses compressed gas to drive filtered water through two parallel XAD-2 resin columns, at about 200 mL/min. No batteries or inverters are required for water collection or processing. Solvent extractions were performed directly in the XAD-2 glass columns. Final extracts are cleaned-up on Florisil cartridges without fractionation and contaminants analyzed by GC-MS. Method detection limits (MDLs) and recoveries for dissolved organic contaminants, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides are reported along with results of surface water analysis for the San Francisco Bay, CA.

Salt deposits in Arizona promise gas-storage opportunities

USGS Publications Warehouse

Rauzi, S.L.

2002-01-01

Massive salt formations and their proximity to pipeline systems and power plants make Arizona attractive for natural gas storage. Caverns dissolved in subsurface salt are used to store LPG at Ferrellgas Partners LP facility near Holbrook and the AmeriGas Partners LP facility near Glendale. Three other companies are investigating the feasibility of storing natural gas in Arizona salt: Copper Eagle Gas Storage LLC, Desert Crossing Gas Storage and Transportation System LLC, and Aquila Inc. The most extensive salt deposits are in the Colorado Plateau Province. Marine and nonmarine salt deposits are present in Arizona.

Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

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

Mau, S.; Romer, M.; Torres, M. E.

Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015more » revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.« less

Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

DOE PAGES

Mau, S.; Romer, M.; Torres, M. E.; ...

2017-02-23

Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015more » revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.« less

NMR of laser-polarized 129Xe in blood foam

NASA Technical Reports Server (NTRS)

Tseng, C. H.; Peled, S.; Nascimben, L.; Oteiza, E.; Walsworth, R. L.; Jolesz, F. A.

1997-01-01

Laser-polarized 129Xe dissolved in a foam preparation of fresh human blood was investigated. The NMR signal of 129Xe dissolved in blood was enhanced by creating a foam in which the dissolved 129Xe exchanged with a large reservoir of gaseous laser-polarized 129Xe. The dissolved 129Xe T1 in this system was found to be significantly shorter in oxygenated blood than in deoxygenated blood. The T1 of 129Xe dissolved in oxygenated blood foam was found to be approximately 21 (+/-5) s, and in deoxygenated blood foam to be greater than 40 s. To understand the oxygenation trend, T1 measurements were also made on plasma and hemoglobin foam preparations. The measurement technique using a foam gas-liquid exchange interface may also be useful for studying foam coarsening and other liquid physical properties.

Shale gas impacts on groundwater resources: insights from monitoring a fracking site in Poland

NASA Astrophysics Data System (ADS)

Montcoudiol, Nelly; Isherwood, Catherine; Gunning, Andrew; Kelly, Thomas; Younger, Paul

2017-04-01

Exploitation of shale gas by hydraulic fracturing (fracking) is highly controversial and concerns have been raised regarding induced risks from this technique. The SHEER project, an EU Horizon 2020-funded project, is looking into developing best practice to understand, prevent and mitigate the potential short- and long-term environmental impacts and risks from shale gas exploration and exploitation. Three major potential impacts were identified: groundwater contamination, air pollution and induced seismicity. This presentation will deal with the hydrogeological aspect. As part of the SHEER project, four monitoring wells were installed at a shale gas exploration site in Northern Poland. They intercept the main drinking water aquifer located in Quaternary sediments. Baseline monitoring was carried out from mid-December 2015 to beginning of June 2016. Fracking operations occurred in two horizontal wells, in two stages, in June and July 2016. The monitoring has continued after fracking was completed, with site visits every 4-6 weeks. Collected data include measurements of groundwater level, conductivity and temperature at 15-minute intervals, frequent sampling for laboratory analyses and field measurements of groundwater physico-chemical parameters. Groundwater samples are analysed for a range of constituents including dissolved gases and isotopes. The presentation will focus on the interpretation of baseline monitoring data. The insights gained into the behaviour of the Quaternary aquifer will allow a greater perspective to be place on the initial project understanding draw from previous studies. Short-term impacts will also be discussed in comparison with the baseline monitoring results. The presentation will conclude with discussion of challenges regarding monitoring of shale gas fracking sites.

Gaseous and particulate water-soluble organic and inorganic nitrogen in rural air in southern Scotland

NASA Astrophysics Data System (ADS)

González Benítez, Juan M.; Cape, J. Neil; Heal, Mathew R.

2010-04-01

Simultaneous daily measurements of water-soluble organic nitrogen (WSON), ammonium and nitrate were made between July and November 2008 at a rural location in south-east Scotland, using a 'Cofer' nebulizing sampler for the gas phase and collection on an open-face PTFE membrane for the particle phase. Average concentrations of NH 3 were 82 ± 17 nmol N m -3 (error is s.d. of triplicate samples), while oxidised N concentrations in the gas phase (from trapping NO 2 and HNO 3) were smaller, at 2.6 ± 2.2 nmol N m -3, and gas-phase WSON concentrations were 18 ± 11 nmol N m -3. The estimated collection efficiency of the nebulizing samplers for the gas phase was 88 (±8) % for NH 3, 37 (±16) % for NO 2 and 57 (±7) % for WSON; reported average concentrations have not been corrected for sampling efficiency. Concentrations in the particle phase were smaller, except for nitrate, at 21 ± 9, 10 ± 6 and 8 ± 9 nmol N m -3, respectively. The absence of correlation in either phase between WSON and either (NH 3 + NH 4+) or NO 3- concentrations suggests atmospheric WSON has diverse sources. During wet days, concentrations of gas and particle-phase inorganic N were lower than on dry days, whereas the converse was true for WSON. These data represent the first reports of simultaneous measurements of gas and particle phase water-soluble nitrogen compounds in rural air on a daily basis, and show that WSON occurs in both phases, contributing 20-25% of the total water-soluble nitrogen in air, in good agreement with earlier data on the contribution of WSON to total dissolved N in rainfall in the UK.

Outgassing From Open And Closed Magma Foams

NASA Astrophysics Data System (ADS)

von Aulock, Felix W.; Kennedy, Ben M.; Maksimenko, Anton; Wadsworth, Fabian B.; Lavallée, Yan

2017-06-01

During magma ascent, bubbles nucleate, grow, coalesce, and form a variably permeable porous network. The volcanic system opens and closes as bubble walls reorganize, seal or fail. In this contribution we cause obsidian to nucleate and grow bubbles to high gas volume fraction at atmospheric pressure by heating samples to 950 ºC for different times and we image the growth through a furnace. Following the experiment, we imaged the internal pore structure of selected samples in 3D and then dissected for analysis of textures and dissolved water content remnant in the glass. We demonstrate that in these high viscosity systems, during foaming and subsequent foam-maturation, bubbles near a free surface resorb via diffusion to produce an impermeable skin of melt around a foam. The skin thickens nonlinearly through time. The water concentrations at the outer and inner skin margins reflect the solubility of water in the melt at the partial pressure of water in atmospheric and water-rich bubble conditions, respectively. In this regime, mass transfer of water out of the system is diffusion limited and the sample shrinks slowly. In a second set of experiments in which we polished off the skin of the foamed samples and placed them back in the furnace, we observe rapid sample contraction and collapse of the connected pore network under surface tension as the system efficiently outgasses. In this regime, mass transfer of water is permeability limited. The mechanisms described here are relevant to the evolution of pore network heterogeneity in permeable magmas. We conclude that diffusion-driven skin formation can efficiently seal connectivity in foams. When rupture of melt film around gas bubbles (i.e. skin removal) occurs, then rapid outgassing and consequent foam collapse modulate gas pressurisation in the vesiculated magma.

Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products.

PubMed

Boulyga, Sergei F; Heilmann, Jens; Heumann, Klaus G

2005-08-01

Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different 34S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured 34S/32S isotope ratio of the isotope-diluted sample remained constant-a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 microg g(-1) ('sulfur-free' premium gasoline) to 10.4 mg g(-1) (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 microg g(-1) and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level.

Fracture Dissolution of Carbonate Rock: An Innovative Process for Gas Storage

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

James W. Castle; Ronald W. Falta; David Bruce

2006-10-31

The goal of the project is to develop and assess the feasibility and economic viability of an innovative concept that may lead to commercialization of new gas-storage capacity near major markets. The investigation involves a new approach to developing underground gas storage in carbonate rock, which is present near major markets in many areas of the United States. Because of the lack of conventional gas storage and the projected growth in demand for storage capacity, many of these areas are likely to experience shortfalls in gas deliverability. Since depleted gas reservoirs and salt formations are nearly non-existent in many areas,more » alternatives to conventional methods of gas storage are required. The need for improved methods of gas storage, particularly for ways to meet peak demand, is increasing. Gas-market conditions are driving the need for higher deliverability and more flexibility in injection/withdrawal cycling. In order to meet these needs, the project involves an innovative approach to developing underground storage capacity by creating caverns in carbonate rock formations by acid dissolution. The basic concept of the acid-dissolution method is to drill to depth, fracture the carbonate rock layer as needed, and then create a cavern using an aqueous acid to dissolve the carbonate rock. Assessing feasibility of the acid-dissolution method included a regional geologic investigation. Data were compiled and analyzed from carbonate formations in six states: Indiana, Ohio, Kentucky, West Virginia, Pennsylvania, and New York. To analyze the requirements for creating storage volume, the following aspects of the dissolution process were examined: weight and volume of rock to be dissolved; gas storage pressure, temperature, and volume at depth; rock solubility; and acid costs. Hydrochloric acid was determined to be the best acid to use because of low cost, high acid solubility, fast reaction rates with carbonate rock, and highly soluble products (calcium chloride) that allow for the easy removal of calcium waste from the well. Physical and chemical analysis of core samples taken from prospective geologic formations for the acid dissolution process confirmed that many of the limestone samples readily dissolved in concentrated hydrochloric acid. Further, some samples contained oily residues that may help to seal the walls of the final cavern structure. These results suggest that there exist carbonate rock formations well suited for the dissolution technology and that the presence of inert impurities had no noticeable effect on the dissolution rate for the carbonate rock. A sensitivity analysis was performed for characteristics of hydraulic fractures induced in carbonate formations to enhance the dissolution process. Multiple fracture simulations were conducted using modeling software that has a fully 3-D fracture geometry package. The simulations, which predict the distribution of fracture geometry and fracture conductivity, show that the stress difference between adjacent beds is the physical property of the formations that has the greatest influence on fracture characteristics by restricting vertical growth. The results indicate that by modifying the fracturing fluid, proppant type, or pumping rate, a fracture can be created with characteristics within a predictable range, which contributes to predicting the geometry of storage caverns created by acid dissolution of carbonate formations. A series of three-dimensional simulations of cavern formation were used to investigate three different configurations of the acid-dissolution process: (a) injection into an open borehole with production from that same borehole and no fracture; (b) injection into an open borehole with production from that same borehole, with an open fracture; and (c) injection into an open borehole connected by a fracture to an adjacent borehole from which the fluids are produced. The two-well configuration maximizes the overall mass transfer from the rock to the fluid, but it results in a complex cavern shape. Numerical simulations were performed to evaluate the ability of storage caverns produced by the acid-dissolution method to store natural gas. In addition, analyses were conducted to evaluate cavern stability during gas injection and withdrawal from storage caverns created in carbonate formations by the acid-dissolution method. The stability analyses were conducted using FLAC2D, a commercially available geotechnical analysis and design software. The analyses indicate that a tall cylindrical cavern with a domed roof and floor will be stable under the expected range of in situ and operational conditions. This result suggests that it should be feasible to avoid mechanical instabilities that could potentially diminish the effectiveness of the storage facility. The feasibility of using pressure transients measured at the ground surface was investigated as a means to evaluate (Abstract truncated)« less

Applying Data Mining Techniques to Chemical Analyses of Pre-drill Groundwater Samples within the Marcellus Formation Shale Play in Bradford County, Pennsylvania

NASA Astrophysics Data System (ADS)

Wen, T.; Niu, X.; Gonzales, M. S.; Li, Z.; Brantley, S.

2017-12-01

Groundwater samples are collected for chemical analyses by shale gas industry consultants in the vicinity of proposed gas wells in Pennsylvania. These data sets are archived so that the chemistry of water from homeowner wells can be compared to chemistry after gas-well drilling. Improved public awareness of groundwater quality issues will contribute to designing strategies for both water resource management and hydrocarbon exploration. We have received water analyses for 11,000 groundwater samples from PA Department of Environmental Protection (PA DEP) in the Marcellus Shale footprint in Bradford County, PA for the years ranging from 2010 to 2016. The PA DEP has investigated these analyses to determine whether gas well drilling or other activities affected water quality. We are currently investigating these analyses to look for patterns in chemistry throughout the study area (related or unrelated to gas drilling activities) and to look for evidence of analytes that may be present at concentrations higher than the advised standards for drinking water. Our preliminary results reveal that dissolved methane concentrations tend to be higher along fault lines in Bradford County [1]. Lead (Pb), arsenic (As), and barium (Ba) are sometimes present at levels above the EPA maximum contaminant level (MCL). Iron (Fe) and manganese (Mn) more frequently violate the EPA standard. We find that concentrations of some chemical analytes (e.g., Ba and Mn) are dependent on bedrock formations (i.e., Catskill vs. Lock Haven) while concentrations of other analytes (e.g., Pb) are not statistically significantly distinct between different bedrock formations. Our investigations are also focused on looking for correlations that might explain water quality patterns with respect to human activities such as gas drilling. However, percentages of water samples failing EPA MCL with respect to Pb, As, and Ba have decreased from previous USGS and PSU studies in the 1990s and 2000s. Public access to pre-drill datasets such as the one we are investigating will allow better understanding of the controls on ground water chemistry, i.e., natural and anthropogenic impacts. [1] Li et al. (2016) Journal of Contaminant Hydrology 195, 23-30.

Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea

PubMed Central

Hung, Chia-Wei; Huang, Kuo-Hao; Shih, Yung-Yen; Lin, Yu-Shih; Chen, Hsin-Hung; Wang, Chau-Chang; Ho, Chuang-Yi; Hung, Chin-Chang; Burdige, David J.

2016-01-01

Hydrocarbon vents have recently been reported to contribute considerable amounts of dissolved organic carbon (DOC) to the oceans. Many such hydrocarbon vents widely exist in the northern South China Sea (NSCS). To investigate if these hydrocarbon vent sites release DOC, we used a real-time video multiple-corer to collect bottom seawater and surface sediments at vent sites. We analyzed concentrations of DOC in these samples and estimated DOC fluxes. Elevated DOC concentrations in the porewaters were found at some sites suggesting that DOC may come from these hydrocarbon vents. Benthic fluxes of DOC from these sediments were 28 to 1264 μmol m−2 d−1 (on average ~321 μmol m−2 d−1) which are several times higher than most DOC fluxes in coastal and continental margin sediments. The results demonstrate that the real-time video multiple-corer can precisely collect samples at vent sites. The estimated benthic DOC flux from the methane venting sites (8.6 × 106 mol y−1), is 24% of the DOC discharge from the Pearl River to the South China Sea, indicating that these sediments make an important contribution to the DOC in deep waters. PMID:27432631

Detailed study of polystyrene solubility using pyrolysis-gas chromatography-mass spectrometry and combination with size-exclusion chromatography.

PubMed

Chojnacka, Aleksandra; Janssen, Hans-Gerd; Schoenmakers, Peter

2014-01-01

Measuring polymer solubility accurately and precisely is challenging. This is especially true at unfavourable solvent compositions, when only very small amounts of polymer dissolve. In this paper, pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) is demonstrated to be much more informative and sensitive than conventional methods, such as ultraviolet spectroscopy. By using a programmed-temperature-vapourisation injector as the pyrolysis chamber, we demonstrate that Py-GC-MS can cover up to five orders of magnitude in dissolved polymer concentrations. For polystyrene, a detection limit of 1 ng mL(-1) is attained. Dissolution in poor solvents is demonstrated to be discriminating in terms of the analyte molecular weight. Py-GC-MS additionally can yield information on polymer composition (e.g. in case of copolymers). In combination with size-exclusion chromatography, Py-GC-MS allows us to estimate the molecular weight distributions of minute amounts of a dissolved polymer and variations therein as a function of time.

Generation and delivery device for ozone gas and ozone dissolved in water

NASA Technical Reports Server (NTRS)

Andrews, Craig C. (Inventor); Murphy, Oliver J. (Inventor)

2004-01-01

The present invention provides an ozone generation and delivery system that lends itself to small scale applications and requires very low maintenance. The system preferably includes an anode reservoir and a cathode phase separator each having a hydrophobic membrane to allow phase separation of produced gases from water. The hydrogen gas, ozone gas and water containing ozone may be delivered under pressure.

Assessment of undiscovered oil and gas resources in the Uteland Butte Member of the Eocene Green River Formation, Uinta Basin, Utah

USGS Publications Warehouse

Johnson, Ronald C.; Birdwell, Justin E.; Mercier, Tracey J.; Brownfield, Michael E.; Charpentier, Ronald R.; Klett, Timothy R.; Leathers, Heidi M.; Schenk, Christopher J.; Tennyson, Marilyn E.

2015-09-03

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered resources of 214 million barrels of oil, 329 billion cubic feet of associated/dissolved natural gas, and 14 million barrels of natural gas liquids in the informal Uteland Butte member of the Green River Formation, Uinta Basin, Utah.

Gas-partitioning tracer test to qualify trapped gas during recharge

USGS Publications Warehouse

Heilweil, Victor M.; Kip, Solomon D.; Perkins, Kim S.; Ellett, Kevin M.

2004-01-01

Dissolved helium and bromide tracers were used to evaluate trapped gas during an infiltration pond experiment. Dissolved helium preferentially partitioned into trapped gas bubbles, or other pore air, because of its low solubility in water. This produced observed helium retardation factors of as much as 12 relative to bromide. Numerical simulations of helium breakthrough with both equilibrium and kinetically limited advection/dispersion/retardation did not match observed helium concentrations. However, better fits were obtained by including a decay term representing the diffusive loss of helium through interconnected, gas-filled pores. Calculations indicate that 7% to more than 26% of the porosity beneath the pond was filled with gas. Measurements of laboratory hydraulic properties indicate that a 10% decrease in saturation would reduce the hydraulic conductivity by at least one order of magnitude in the well-sorted sandstone, but less in the overlying soils. This is consistent with in situ measurements during the experiment, which show steeper hydraulic gradients in sandstone than in soil. Intrinsic permeability of the soil doubled during the first six months of the experiment, likely caused by a combination of dissolution and thermal contraction of trapped gas. Managers of artificial recharge basins may consider minimizing the amount of trapped gas by using wet, rather than dry, tilling to optimize infiltration rates, particularly in well-sorted porous media in which reintroduced trapped gas may cause substantial reductions in permeability. Trapped gas may also inhibit the amount of focused infiltration that occurs naturally during ephemeral flood events along washes and playas.

Gas-partitioning tracer test to quantify trapped gas during recharge

USGS Publications Warehouse

Heilweil, V.M.; Solomon, D.K.; Perkins, K.S.; Ellett, K.M.

2004-01-01

Dissolved helium and bromide tracers were used to evaluate trapped gas during an infiltration pond experiment. Dissolved helium preferentially partitioned into trapped gas bubbles, or other pore air, because of its low solubility in water. This produced observed helium retardation factors of as much as 12 relative to bromide. Numerical simulations of helium breakthrough with both equilibrium and kinetically limited advection/dispersion/retardation did not match observed helium concentrations. However, better fits were obtained by including a decay term representing the diffusive loss of helium through interconnected, gas-filled pores. Calculations indicate that 7% to more than 26% of the porosity beneath the pond was filled with gas. Measurements of laboratory hydraulic properties indicate that a 10% decrease in saturation would reduce the hydraulic conductivity by at least one order of magnitude in the well-sorted sandstone, but less in the overlying soils. This is consistent with in situ measurements during the experiment, which show steeper hydraulic gradients in sandstone than in soil. Intrinsic permeability of the soil doubled during the first six months of the experiment, likely caused by a combination of dissolution and thermal contraction of trapped gas. Managers of artificial recharge basins may consider minimizing the amount of trapped gas by using wet, rather than dry, tilling to optimize infiltration rates, particularly in well-sorted porous media in which reintroduced trapped gas may cause substantial reductions in permeability. Trapped gas may also inhibit the amount of focused infiltration that occurs naturally during ephemeral flood events along washes and playas.

Infiltration from an impoundment for coal‐bed natural gas, Powder River Basin, Wyoming: Evolution of water and sediment chemistry

USGS Publications Warehouse

Healy, Richard W.; Rice, Cynthia A.; Bartos, Timothy T.; P. McKinley, Michael

2008-01-01

Development of coal‐bed natural gas (CBNG) in the Powder River Basin, Wyoming, has increased substantially in recent years. Among environmental concerns associated with this development is the fate of groundwater removed with the gas. A preferred water‐management option is storage in surface impoundments. As of January 2007, permits for more than 4000 impoundments had been issued within Wyoming. A study was conducted on changes in water and sediment chemistry as water from an impoundment infiltrated the subsurface. Sediment cores were collected prior to operation of the impoundment and after its closure and reclamation. Suction lysimeters were used to collect water samples from beneath the impoundment. Large amounts of chloride (12,300 kg) and nitrate (13,500 kg as N), most of which accumulated naturally in the sediments over thousands of years, were released into groundwater by infiltrating water. Nitrate was more readily flushed from the sediments than chloride. If sediments at other impoundment locations contain similar amounts of chloride and nitrate, impoundments already permitted could release over 48 × 106 kg of chloride and 52 × 106 kg of nitrate into groundwater in the basin. A solute plume with total dissolved solid (TDS) concentrations at times exceeding 100,000 mg/L was created in the subsurface. TDS concentrations in the plume were substantially greater than those in the CBNG water (about 2300 mg/L) and in the ambient shallow groundwater (about 8000 mg/L). Sulfate, sodium, and magnesium are the dominant ions in the plume. The elevated concentrations are attributed to cation‐exchange‐enhanced gypsum dissolution. As gypsum dissolves, calcium goes into solution and is exchanged for sodium and magnesium on clays. Removal of calcium from solution allows further gypsum dissolution.

Fabrication, properties, and applications of porous metals with directional pores

PubMed Central

NAKAJIMA, Hideo

2010-01-01

Lotus-type porous metals with aligned long cylindrical pores are fabricated by unidirectional solidification from the melt with a dissolved gas such as hydrogen, nitrogen, or oxygen. The gas atoms can be dissolved into the melt via a pressurized gas atmosphere or thermal decomposition of gaseous compounds. Three types of solidification techniques have been developed: mold casting, continuous zone melting, and continuous casting techniques. The last method is superior from the viewpoint of mass production of lotus metals. The observed anisotropic behaviors of the mechanical properties, sound absorption, and thermal conductivity are inherent to the anisotropic porous structure. In particular, the remarkable anisotropy in the mechanical strength is attributed to the stress concentration around the pores aligned perpendicular to the loading direction. Heat sinks are a promising application of lotus metals due to the high cooling performance with a large heat transfer. PMID:21084772

Fabrication, properties, and applications of porous metals with directional pores.

PubMed

Nakajima, Hideo

2010-01-01

Lotus-type porous metals with aligned long cylindrical pores are fabricated by unidirectional solidification from the melt with a dissolved gas such as hydrogen, nitrogen, or oxygen. The gas atoms can be dissolved into the melt via a pressurized gas atmosphere or thermal decomposition of gaseous compounds. Three types of solidification techniques have been developed: mold casting, continuous zone melting, and continuous casting techniques. The last method is superior from the viewpoint of mass production of lotus metals. The observed anisotropic behaviors of the mechanical properties, sound absorption, and thermal conductivity are inherent to the anisotropic porous structure. In particular, the remarkable anisotropy in the mechanical strength is attributed to the stress concentration around the pores aligned perpendicular to the loading direction. Heat sinks are a promising application of lotus metals due to the high cooling performance with a large heat transfer.

Experimental study on the impact of temperature on the dissipation process of supersaturated total dissolved gas.

PubMed

Shen, Xia; Liu, Shengyun; Li, Ran; Ou, Yangming

2014-09-01

Water temperature not only affects the solubility of gas in water but can also be an important factor in the dissipation process of supersaturated total dissolved gas (TDG). The quantitative relationship between the dissipation process and temperature has not been previously described. This relationship affects the accurate evaluation of the dissipation process and the subsequent biological effects. This article experimentally investigates the impact of temperature on supersaturated TDG dissipation in static and turbulent conditions. The results show that the supersaturated TDG dissipation coefficient increases with the temperature and turbulence intensity. The quantitative relationship was verified by straight flume experiments. This study enhances our understanding of the dissipation of supersaturated TDG. Furthermore, it provides a scientific foundation for the accurate prediction of the dissipation process of supersaturated TDG in the downstream area and the negative impacts of high dam projects on aquatic ecosystems. Copyright © 2014. Published by Elsevier B.V.

The Effect of Foaming and Silica Dissolution on Melter Feed Rheology during Conversion to Glass

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

Marcial, Jose; Chun, Jaehun; Hrma, Pavel R.

As the nuclear waste glass melter feed is converted to molten glass, the feed eventually becomes a continuous glass-forming melt in which dissolving refractory constituents are suspended together with numerous gas bubbles. Knowledge of mechanical properties of the melter feed is crucial for understanding the feed-to-glass conversion as it occurs in the cold cap. We measured the viscosity during heating of the feed and correlated it with the independently determined volume fractions of dissolving quartz particles and the gas phase. The measurement was performed with a rotating spindle rheometer on the melter feed heated at 5 K/min starting at severalmore » different temperatures. The effect of quartz particles, gas bubbles, and compositional inhomogeneity on the glass-forming melt viscosity was determined by fitting a linear relationship between log viscosity and volume fractions of suspended phases to data.« less

Process for coal liquefaction in staged dissolvers

DOEpatents

Roberts, George W.; Givens, Edwin N.; Skinner, Ronald W.

1983-01-01

There is described an improved liquefaction process by which coal is converted to a low ash and low sulfur carbonaceous material that can be used as a fuel in an environmentally acceptable manner without costly gas scrubbing equipment. In the process, coal is slurried with a pasting oil, passed through a preheater and at least two dissolvers in series in the presence of hydrogen-rich gases at elevated temperatures and pressures. Solids, including mineral ash and unconverted coal macerals, are separated from the condensed reactor effluent. In accordance with the improved process, the first dissolver is operated at a higher temperature than the second dissolver. This temperature sequence produces improved product selectivity and permits the incorporation of sufficient hydrogen in the solvent for adequate recycle operations.

Release of Dissolved CO2 from Water in Laboratory Porous Media Following Rapid Depressurization

NASA Astrophysics Data System (ADS)

Crews, J. B.; Cooper, C. A.

2011-12-01

A bench-top laboratory study is undertaken to investigate the effects of seismic shocks on brine aquifers into which carbon dioxide has been injected for permanent storage. Long-term storage in deep saline aquifers has been proposed and studied as one of the most viable near-term options for sequestering fossil fuel-derived carbon dioxide from the atmosphere to curb anthropogenic climate change. Upon injection into the subsurface, it is expected that CO2, as either a gas or supercritical fluid, will mix convectively with the formation water. The possibility exists, however, that dissolved CO2 will come out of solution as a result of an earthquake. The effect is similar to that of slamming an unsealed container of carbonated beverage on a table; previously dissolved CO2 precipitates, forms bubbles, and rises due to buoyancy. In this study, we measure the change in gas-phase CO2 concentration as a function of the magnitude of the shock and the initial concentration of CO2. In addition, we investigate and seek to characterize the nucleation and transport of CO2 bubbles in a porous medium after a seismic shock. Experiments are conducted using a Hele-Shaw cell and a CCD camera to quantify the fraction of dissolved CO2 that comes out of solution as a result of a sharp mechanical impulse. The data are used to identify and constrain the conditions under which CO2 comes out of solution and, further, to understand the end-behavior of the precipitated gas-phase CO2 as it moves through or is immobilized in a porous medium.

In situ Measurements of Dissolved Gas Dynamics and Root Uptake in the Wetland Rhizosphere

NASA Astrophysics Data System (ADS)

Reid, Matthew; Jaffe, Peter

2013-04-01

Anaerobic wetland soils are important natural sources of various atmospheric trace gases that are detrimental to the environment, including methane (CH4), nitrous oxide, elemental mercury (Hg°), and halomethanes. The balance between production and uptake in soils depends, in part, on mass transfer within the soil and between soil and the atmosphere. Observed volatilization rates of trace gases are highly variable and poorly described by models, however, so there is a clear need for new process measurements to clarify the rates of these transport mechanisms. Here we present results from mesocosm push-pull tests intended to quantify transport processes of dissolved gases in wetland sediments, with a focus on uptake by wetland plant roots and partitioning into trapped gas bubbles. This technique uses a suite of nonreactive volatile tracers to pinpoint transport mechanisms without the confounding influence of biochemical transformations. Mass balance approaches are used to determine transport kinetics, and a new analytical method to interpret dissolved gas push-pull test data is presented and compared to traditional analytical techniques. Results confirm the key role of vegetation in dramatically enhancing removal rates of dissolved gases from wetland soils. Root uptake is shown to be diffusion-limited and relative root uptake rates are modeled as an empirical function of molecular size. We use the porewater removal rates measured here to estimate potential volatilization fluxes of CH4, methyl chloride, and Hg° from wetlands vegetated with Typha latifolia and Scirpus acutus. The implementation of this new push-pull test methodology to field settings will be discussed.

Comparative performance of CO2 measuring methods: marine aquaculture recirculation system application

USGS Publications Warehouse

Pfeiffer, T.J.; Summerfelt, S.T.; Watten, B.J.

2011-01-01

Many methods are available for the measurement of dissolved carbon dioxide in an aqueous environment. Standard titration is the typical field method for measuring dissolved CO2 in aquaculture systems. However, titrimetric determination of dissolved CO2 in marine water aquaculture systems is unsuitable because of the high dissolved solids, silicates, and other dissolved minerals that interfere with the determination. Other methods used to measure dissolved carbon dioxide in an aquaculture water included use of a wetted CO2 probe analyzer, standard nomographic methods, and calculation by direct measurements of the water's pH, temperature, and alkalinity. The determination of dissolved CO2 in saltwater based on partial pressure measurements and non-dispersive infra-red (NDIR) techniques with a CO2 gas analyzer are widely employed for oceanic surveys of surface ocean CO2 flux and are similar to the techniques employed with the head space unit (HSU) in this study. Dissolved carbon dioxide (DC) determination with the HSU using a infra-red gas analyzer (IRGA) was compared with titrimetric, nomographic, calculated, and probe measurements of CO2 in freshwater and in saltwater with a salinity ranging from 5.0 to 30 ppt, and a CO2 range from 8 to 50 mg/L. Differences in CO2 measurements between duplicate HSUs (0.1–0.2 mg/L) were not statistically significant different. The coefficient of variation for the HSU readings averaged 1.85% which was better than the CO2 probe (4.09%) and that for the titrimetric method (5.84%). In all low, medium and high salinity level trials HSU precision was good, averaging 3.39%. Differences existed between comparison testing of the CO2 probe and HSU measurements with the CO2 probe readings, on average, providing DC estimates that were higher than HSU estimates. Differences between HSU and titration based estimates of DC increased with salinity and reached a maximum at 32.2 ppt. These differences were statistically significant (P < 0.05) at all salinity levels greater than 0.3 ppt. Results indicated reliable replicated results from the head space unit with varying salinity and dissolved carbon dioxide concentrations.

Development of a prototype for dissolved CO2 rapid measurement and preliminary tests

NASA Astrophysics Data System (ADS)

Li, Meng; Guo, Jinjia; Zhang, Zhihao; Luo, Zhao; Qin, Chuan; Zheng, Ronger

2017-10-01

The measurements of dissolved CO2 in seawater is of great significance for the study of global carbon cycle. At present, the commercial sensors used for dissolved CO2 measurements are mostly equipped with permeable membranes for the purpose of gas-liquid separation, with the advantages of easy operation, low cost, etc.. However, most of these devices measure CO2 after reaching gas equilibrium, so it takes a few minutes to respond, which limited its applications in rapid measurements. In this paper, a set of prototype was developed for the rapid measurements of dissolved CO2. The system was built basing the direct absorption TDLAS. To detect the CO2 absorption line located at 4991.26 cm-1 , a fiber-coupled DFB laser operating at 2004 nm was selected as the light source. A Herriott type multi-pass cavity with an effective optical path length of 10 m and an inner volume of 90 mL was used for absorption measurements. A detection limit of 26 μatm can be obtained with this compact cavity. To realize the rapid measurements of dissolved CO2, a degasser with high degassing rate was necessary. A hollow fiber membrane with a large permeable area used in this paper can achieve degassing rate up to 2.88 kPa/min. Benefitted from the high degassing rate of the degasser and high sensitivity of the compact TDLAS system, a rapid measurement of dissolved CO2 in water can be achieved within 1s time, and the response time of the prototype when the dissolved CO2 concentration changed abruptly in actual measurement was 15 s. To evaluate the performance of the prototype, comparison measurements were carried out with a commercial mass spectrometer. The dissolved CO2 in both seawater and tap-water was measured, and the experimental results showed good consistent trends with R2 of 0.973 and 0.931. The experimental results proved the feasibility of dissolved CO2 rapid measurement. In the near future, more system evaluation experiments will be carried out and the system will be further optimized focusing on the underwater in-situ detection system.

Dissolution flowsheet for high flux isotope reactor fuel

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

Foster, T.

2016-09-27

As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U 3O 8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H 2. The HFIR fuel cores will be dissolved and the recovered U will be down-blendedmore » into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H 2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H 2 and other permanent gases in the dissolution offgas allowing the development of H 2 generation rate profiles. The H 2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the calculated lower flammability limit (LFL) for H 2 at a given Hg concentration.« less

The effect of membrane filtration on dissolved trace element concentrations

USGS Publications Warehouse

Horowitz, A.J.; Lum, K.R.; Garbarino, J.R.; Hall, G.E.M.; Lemieux, C.; Demas, C.R.

1996-01-01

The almost universally accepted operational definition for dissolved constituents is based on processing whole-water samples through a 0.45-??m membrane filter. Results from field and laboratory experiments indicate that a number of factors associated with filtration, other than just pore size (e.g., diameter, manufacturer, volume of sample processed, amount of suspended sediment in the sample), can produce substantial variations in the 'dissolved' concentrations of such elements as Fe, Al, Cu, Zn, Pb, Co, and Ni. These variations result from the inclusion/exclusion of colloidally- associated trace elements. Thus, 'dissolved' concentrations quantitated by analyzing filtrates generated by processing whole-water through similar pore- sized membrane filters may not be equal/comparable. As such, simple filtration through a 0.45-??m membrane filter may no longer represent an acceptable operational definition for dissolved chemical constituents. This conclusion may have important implications for environmental studies and regulatory agencies.

PCBs, PCDD/Fs and PAHs in dissolved, suspended and settling particulate matrixes from the Baltic Sea

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

Naef, C.; Broman, D.; Zebuehr, Y.

The occurrence and dynamics of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) are discussed on the basis of results from samples taken at pristine coastal and off shore locations in the Baltic Sea. The sampling techniques used were high volume cross flow filtration and sediment traps for suspended and settling particulate matter, respectively, and polyurethane foam adsorbents for the compounds associated with the apparently dissolved fractions. All samples were Soxhlet extracted with toluene and separated on a HPLC system followed by quantification on GS/MS. The importance of parameters such as concentrations of particulate lipids, particulatemore » organic carbon and dissolved organic carbon, etc. for the distribution of the compounds between the suspended and settling particulate matrixes and the dissolved phase in the water are discussed. In situ determined particulate organic carbon-water partition coefficients as well as predicted dissolved organic carbon-water partition coefficients and approximations of the average ``truly`` dissolved concentrations are presented. The particulate and dissolved concentrations in the mixed surface layer are discussed in perspective to the particulate flux of PCBs, PCDD/Fs and PAHs.« less

Variations in organic carbon chemistry in the Gulf Coast and coastal marshes following the Deepwater Horizon oil spill

NASA Astrophysics Data System (ADS)

Holloway, J. M.; Orem, W. H.; Aiken, G.; Varonka, M. S.; Butler, K.; Kokaly, R. F.

2011-12-01

Record volumes of oil released from the Macondo well following the explosion of the Deepwater Horizon offshore oil-drilling platform in the Gulf of Mexico significantly impacted coastal marshes in Barataria Bay, Louisiana. Remote sensing and water sampling was conducted by the U.S. Geological Survey to evaluate the extent of impact. Water samples were collected offshore from near the spill site July 5-10, 2010 to characterize molecular organic carbon chemistry on unfiltered samples and dissolved organic carbon (DOC) on filtered samples. Three field visits were conducted in July 7-10, August 12-14, and August 24-26, 2010, to collect samples from the soil-water interface in coastal marshes along lower Barataria Bay and the Bird's Foot Delta at the distal end of the Mississippi River Delta. Visible oil in the marsh was observed as thick coatings on vegetation and soil and as sheens at the water surface. Samples were extracted for hydrocarbons with dichloromethane, separated into aliphatic, aromatic and polar compound classes using standard column techniques, and analyzed by gas chromatography/mass spectrometry. A significant amount of oil was observed "dissolved" in the water column with a hydrocarbon distribution resembling that of the surface oil slick. While oils maintained many of the more volatile lower molecular weight components near the spill site, these were mostly gone in the onshore Barataria Bay samples, leaving mostly higher molecular weight components. Dissolved organic carbon was characterized using concentration, fluorescence index (FI), specific ultratviolet absorbance (SUVA) and excitation/emission fluorescence (EEM). Offshore samples had distinctive EEMs patterns, SUVA and FI. With few exceptions, marsh samples had EEMs patterns more similar to previously extracted organic matter from the Mississippi River than to the offshore oil. In spite of visible oil sheen in unfiltered water from contaminated shorelines and no visible sign of impact on vegetation in the "control" sites with no visible oil on vegetation, DOC concentrations were similar in impacted and visibly unimpacted sites in Barataria Bay. There was an increase in specific UV absorbance (SUVA), an index of aromaticity, with increasing DOC concentrations at some repeatedly sampled sites, either due to seasonal effects or continued dissolution of petroleum compounds. These data reflect the degradation of oil during transport from the spill site to coastal marshes. Ongoing studies to track oil impacts on coastal marshes included sampling oiled and unimpacted areas in Barataria Bay for extractable hydrocarbons in July 2011, more than a year after the spill.

Specific Conductance and Dissolved-Solids Characteristics for the Green River and Muddy Creek, Wyoming, Water Years 1999-2008

USGS Publications Warehouse

Clark, Melanie L.; Davidson, Seth L.

2009-01-01

Southwestern Wyoming is an area of diverse scenery, wildlife, and natural resources that is actively undergoing energy development. The U.S. Department of the Interior's Wyoming Landscape Conservation Initiative is a long-term science-based effort to assess and enhance aquatic and terrestrial habitats at a landscape scale, while facilitating responsible energy development through local collaboration and partnerships. Water-quality monitoring has been conducted by the U.S. Geological Survey on the Green River near Green River, Wyoming, and Muddy Creek near Baggs, Wyoming. This monitoring, which is being conducted in cooperation with State and other Federal agencies and as part of the Wyoming Landscape Conservation Initiative, is in response to concerns about potentially increased dissolved solids in the Colorado River Basin as a result of energy development. Because of the need to provide real-time dissolved-solids concentrations for the Green River and Muddy Creek on the World Wide Web, the U.S. Geological Survey developed regression equations to estimate dissolved-solids concentrations on the basis of continuous specific conductance using relations between measured specific conductance and dissolved-solids concentrations. Specific conductance and dissolved-solids concentrations were less varied and generally lower for the Green River than for Muddy Creek. The median dissolved-solids concentration for the site on the Green River was 318 milligrams per liter, and the median concentration for the site on Muddy Creek was 943 milligrams per liter. Dissolved-solids concentrations ranged from 187 to 594 milligrams per liter in samples collected from the Green River during water years 1999-2008. Dissolved-solids concentrations ranged from 293 to 2,485 milligrams per liter in samples collected from Muddy Creek during water years 2006-08. The differences in dissolved-solids concentrations in samples collected from the Green River compared to samples collected from Muddy Creek reflect the different basin characteristics. Relations between specific conductance and dissolved-solids concentrations were statistically significant for the Green River (p-value less than 0.001) and Muddy Creek (p-value less than 0.001); therefore, specific conductance can be used to estimate dissolved-solids concentrations. Using continuous specific conductance values to estimate dissolved solids in real-time on the World Wide Web increases the amount and improves the timeliness of data available to water managers for assessing dissolved-solids concentrations in the Colorado River Basin.

Low-Level detections of halogenated volatile organic compounds in groundwater: Use in vulnerability assessments

USGS Publications Warehouse

Plummer, Niel; Busenberg, E.; Eberts, S.M.; Bexfield, L.M.; Brown, C.J.; Fahlquist, L.S.; Katz, B.G.; Landon, M.K.

2008-01-01

Concentrations of halogenated volatile organic compounds (VOCs) were determined by gas chromatography (GC) with an electron-capture detector (GC-ECD) and by gas chromatography with mass spectrometry (GC-MS) in 109 groundwater samples from five study areas in the United States. In each case, the untreated water sample was used for drinking-water purposes or was from a monitoring well in an area near a drinking-water source. The minimum detection levels (MDLs) for 25 VOCs that were identified in GC-ECD chromatograms, typically, were two to more than four orders of magnitude below the GC-MS MDLs. At least six halogenated VOCs were detected in all of the water samples analyzed by GC-ECD, although one or more VOCs were detected in only 43% of the water samples analyzed by GC-MS. In nearly all of the samples, VOC concentrations were very low and presented no known health risk. Most of the low-level VOC detections indicated post-1940s recharge, or mixtures of recharge that contained a fraction of post-1940s water. Concentrations of selected halogenated VOCs in groundwater from natural and anthropogenic atmospheric sources were estimated and used to recognize water samples that are being impacted by nonatmospheric sources. A classification is presented to perform vulnerability assessments at the scale of individual wells using the number of halogenated VOC detections and total dissolved VOC concentrations in samples of untreated drinking water. The low-level VOC detections are useful in vulnerability assessments, particularly for samples in which no VOCs are detected by GC-MS analysis.

Groundwater-quality characteristics for the Wyoming Groundwater-Quality Monitoring Network, November 2009 through September 2012

USGS Publications Warehouse

Boughton, Gregory K.

2014-01-01

Groundwater samples were collected from 146 shallow (less than or equal to 500 feet deep) wells for the Wyoming Groundwater-Quality Monitoring Network, from November 2009 through September 2012. Groundwater samples were analyzed for physical characteristics, major ions and dissolved solids, trace elements, nutrients and dissolved organic carbon, uranium, stable isotopes of hydrogen and oxygen, volatile organic compounds, and coliform bacteria. Selected samples also were analyzed for gross alpha radioactivity, gross beta radioactivity, radon, tritium, gasoline range organics, diesel range organics, dissolved hydrocarbon gases (methane, ethene, and ethane), and wastewater compounds. Water-quality measurements and concentrations in some samples exceeded numerous U.S. Environmental Protection Agency (EPA) drinking water standards. Physical characteristics and constituents that exceeded EPA Maximum Contaminant Levels (MCLs) in some samples were arsenic, selenium, nitrite, nitrate, gross alpha activity, and uranium. Total coliforms and Escherichia coli in some samples exceeded EPA Maximum Contaminant Level Goals. Measurements of pH and turbidity and concentrations of chloride, sulfate, fluoride, dissolved solids, aluminum, iron, and manganese exceeded EPA Secondary Maximum Contaminant Levels in some samples. Radon concentrations in some samples exceeded the alternative MCL proposed by the EPA. Molybdenum and boron concentrations in some samples exceeded EPA Health Advisory Levels. Water-quality measurements and concentrations also exceeded numerous Wyoming Department of Environmental Quality (WDEQ) groundwater standards. Physical characteristics and constituents that exceeded WDEQ Class I domestic groundwater standards in some samples were measurements of pH and concentrations of chloride, sulfate, dissolved solids, iron, manganese, boron, selenium, nitrite, and nitrate. Measurements of pH and concentrations of chloride, sulfate, dissolved solids, aluminum, iron, manganese, boron, and selenium exceeded WDEQ Class II agriculture groundwater standards in some samples. Measurements of pH and concentrations of sulfate, dissolved solids, aluminum, boron, and selenium exceeded WDEQ Class III livestock groundwater standards in some samples. The concentrations of dissolved solids in two samples exceeded the WDEQ Class IV industry groundwater standard. Measurements of pH and concentrations of dissolved solids, aluminum, iron, manganese, and selenium exceeded WDEQ Class special (A) fish and aquatic life groundwater standards in some samples. Stable isotopes of hydrogen and oxygen measured in water samples were compared to the Global Meteoric Water Line and Local Meteoric Water Lines. Results indicated that recharge to all of the wells was derived from precipitation and that the water has undergone some fractionation, possibly because of evaporation. Concentrations of organic compounds did not exceed any State or Federal water-quality standards. Few volatile organic compounds were detected in samples, whereas gasoline range organics, diesel range organics, and methane were detected most frequently. Concentrations of wastewater compounds did not exceed any State or Federal water-quality standards. The compounds N,N-diethyl-meta-toluamide (DEET), benzophenone, and phenanthrene were detected most frequently. Bacteria samples were collected, processed, incubated, and enumerated in the field or at the U.S. Geological Survey Wyoming-Montana Water Science Center. Total coliforms and Escherichia coli were detected in some samples.

Spontaneous Growth and Mobilization of a Gas Phase in the Presence of Dense Non- Aqueous Phase Liquid (DNAPL)

NASA Astrophysics Data System (ADS)

Roy, J. W.; Smith, J. E.

2006-12-01

A number of mechanisms can lead to the presence of disconnected bubbles or ganglia of gas phase in groundwater. When associated with or near a DNAPL phase, the disconnected gas phase experiences mass transfer of dissolved gases including the volatile components of the DNAPL. The properties of the gas phase interface, such as interfacial tension and contact angle, can also be affected. This work addresses the behavior of spontaneous continual growth of initially trapped seed gas bubbles within DNAPL source zones. Three different experiments were performed in a 2-dimensional transparent flow cell 15 cm by 20 cm by 1.5 cm. In each case, a DNAPL pool was created within larger glass beads over smaller glass beads that served as a capillary barrier. The DNAPL consisted of either a 1:2 (v/v) tetrachloroethene (PCE) to benzene mixture, single component PCE, or single component TCE. The experiments effectively demonstrate spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone. A cycle of gas phase growth and mobilization was facilitated by the presence of secondary seed bubbles left behind due to snap-off during vertical bubble (ganglion) mobilization. This gas phase growth process was relatively slow but continuous and could be expected to continue until the NAPL is completely dissolved. Some implications of the demonstrated behavior for water flow and mass transfer within and near the DNAPL source zone are highlighted.

Pore Formation and Mobility Investigation (PPMI): Description and Initial Analysis of Experiments Conducted aboard the International Space Station

NASA Technical Reports Server (NTRS)

Grugel, R. N.; Anilkumar, A. V.; Lee, C. P.

2003-01-01

Flow visualization experiments during the controlled directional melt back and re-solidification of succinonitrile (SCN) and SCN-water mixtures were conducted using the Pore Formation and Mobility Investigation (PFMI) apparatus in the glovebox facility (GBX) aboard the International Space Station. The study samples were initially 'cast' on earth under 450 millibar of nitrogen into 1 cm ID glass sample tubes approximately 30 cm in length, containing 6 in situ thermocouples. During the Space experiments, the processing parameters and flow visualization settings are remotely monitored and manipulated from the ground Telescience Center (TSC). The ground solidified sample is first subjected to a unidirectional melt back, generally at 10 microns per second, with a constant temperature gradient ahead of the melting interface. Bubbles of different sizes are seen to initiate at the melt interface and, upon release from the melting solid, translate at different speeds in the temperature field ahead of them before coming to rest. Over a period of time these bubbles dissolve into the melt. The gas-laden liquid is then directionally solidified in a controlled manner, generally starting at a rate of 1 micron /sec. Observation and preliminary analysis of bubble formation and mobility in pure SCN samples during melt back and the subsequent structure resulting during gas generation upon re-solidification are presented and discussed.

Pore Formation and Mobility Investigation (PFMI): Description and Initial Analysis of Experiments Conducted aboard the International Space Station

NASA Technical Reports Server (NTRS)

Grugel, R. N.; Anilkumar, A. V.; Lee, C. P.

2002-01-01

Flow visualization experiments during the controlled directional melt back and re-solidification of succinonitrile (SCN) and SCN-water mixtures were conducted using the Pore Formation and Mobility Investigation (PFMI) apparatus in the glovebox facility (GBX) aboard the International Space Station. The study samples were initially "cast" on earth under 450 millibar of nitrogen into 1 cm ID glass sample tubes approximately 30 cm in length, containing 6 in situ thermocouples. During the Space experiments, the processing parameters and flow visualization settings are remotely monitored and manipulated from the ground Telescience Center (TSC). The ground solidified sample is first subjected to a unidirectional melt back, generally at 10 microns per second, with a constant temperature gradient ahead of the melting interface. Bubbles of different sizes are seen to initiate at the melt interface and, upon release from the melting solid, translate at different speeds in the temperature field ahead of them before coming to rest. Over a period of time these bubbles dissolve into the melt. The gas-laden liquid is then directionally solidified in a controlled manner, generally starting at a rate of 1 micron /sec. Observation and preliminary analysis of bubble formation and mobility in pure SCN samples during melt back and the subsequent structure resulting during gas generation upon re-solidification are presented and discussed.

New radiocarbon measurement methods in the Hertelendi Laboratory, Hungary

NASA Astrophysics Data System (ADS)

Janovics, Róbert; Major, István; Rinyu, László; Veres, Mihály; Molnár, Mihály

2013-04-01

In this paper we present two very different and novel methods for C-14 measurement from dissolved inorganic carbonate (DIC) of water samples. A new LSC sample preparation method for liquid scintillation C-14 measurements was implemented in the ATOMKI. The first method uses direct absorption into a special absorbent (Carbosorb E®) and a following liquid scintillation measurement. Typical sample size is 20-40 litre of water. The developed CO2 absorption method is fast, and simple. The C-14 activities is measured by an ultra low background LSC (TRI-CARB 3170 TR/SL, Perkin Elmer) including quenching parameter (tSIE).The corresponding limit of C-14 dating is 31200 year. Several tests were executed with old borehole CO2 gas without significant content of C-14 and also performed on samples of known C-14 activities between 29 and 7000 pMC, previously measured by GPC. The combined uncertainty of the described determination is about 2 % in the case of recent carbon. It is a very cost-effective and easy to use method based on a novel and simple static absorption process for the CO2 extracted from groundwater. The other very sensitive method is based on accelerator mass spectrometry (AMS) using gas ion source. This method does not require graphite generation and a small volume of water sample (1-20mL) is enough for the radiocarbon measurement. The procedure is very similar to pre-treatment of carbonate contained sample preparation for stable isotope measurement with gasbench technique. We applied a MICADAS type accelerator mass spectrometry (AMS) with gas ion source for C-14 analysis. The radiocarbon content of water was sat free with phosphoric acid and then the headspace gas was rinsed vials. The whole measurement needs only 20 min of each sample. The precision of measurement is better than 1% for modern samples. The preparation is vastly reduced compared to the other AMS methods and principally allows fully automated measurements of groundwater samples with an auto-sampler. The presented two new methods can be suitable for C-14 measurements and dating of hydrological, and environmental samples as well. The new AMS facility in ATOMKI (Debrecen, Hungary) using an EnvironMICADAS AMS system with gas ion source has a great potential in groundwater C-14 analyses. The research was supported by the by TÁMOP-4.2.2.A-11/1/KONV and the Hungarian NSF (OTKA MB08-A 81515)

Laboratory-Scale Demonstration Using Dilute Ammonia Gas-Induced Alkaline Hydrolysis of Soil Contaminants (Chlorinated Propanes and Explosives)

DTIC Science & Technology

2016-06-01

Hydrolysis of Soil Contaminants (Chlorinated Propanes and Explosives) En vi ro nm en ta l L ab or at or y Victor F. Medina, Scott A. Waisner, Charles...Using Dilute Ammonia Gas-Induced Alkaline Hydrolysis of Soil Contaminants (Chlorinated Propanes and Explosives) Victor F. Medina, Scott A. Waisner...hydrolysis. This project explored the use of ammonia gas to raise soil pH in order to stimulate alkaline hydrolysis. When ammonia gas dissolves in water

Cavitation Inception Scale Effects. 1. Nuclei Distributions in Natural Waters. 2. Cavitation Inception in a Turbulent Shear Flow.

DTIC Science & Technology

1987-05-01

ratio of specific heats for the gas and an adiabatic bubble pressure- volume relation has been assumed (Plesset & Prosperetti 1977). When viscosity...pressure because of surface tension at the gas -liquid interface , so the gas is stabilized in the crevice and will not dissolve into the liquid. The concave... interface toward the gas is estab- lished by the hydrophobic nature of the particle, and results in surface tension acting to oppose the liquid

Quality of major ion and total dissolved solids data from groundwater sampled by the National Water-Quality Assessment Program, 1992–2010

USGS Publications Warehouse

Gross, Eliza L.; Lindsey, Bruce D.; Rupert, Michael G.

2012-01-01

Field blank samples help determine the frequency and magnitude of contamination bias, and replicate samples help determine the sampling variability (error) of measured analyte concentrations. Quality control data were evaluated for calcium, magnesium, sodium, potassium, chloride, sulfate, fluoride, silica, and total dissolved solids. A 99-percent upper confidence limit is calculated from field blanks to assess the potential for contamination bias. For magnesium, potassium, chloride, sulfate, and fluoride, potential contamination in more than 95 percent of environmental samples is less than or equal to the common maximum reporting level. Contamination bias has little effect on measured concentrations greater than 4.74 mg/L (milligrams per liter) for calcium, 14.98 mg/L for silica, 4.9 mg/L for sodium, and 120 mg/L for total dissolved solids. Estimates of sampling variability are calculated for high and low ranges of concentration for major ions and total dissolved solids. Examples showing the calculation of confidence intervals and how to determine whether measured differences between two water samples are significant are presented.

Groundwater methane in relation to oil and gas development and shallow coal seams in the Denver-Julesburg Basin of Colorado

PubMed Central

Sherwood, Owen A.; Rogers, Jessica D.; Lackey, Greg; Burke, Troy L.; Osborn, Stephen G.; Ryan, Joseph N.

2016-01-01

Unconventional oil and gas development has generated intense public concerns about potential impacts to groundwater quality. Specific pathways of contamination have been identified; however, overall rates of contamination remain ambiguous. We used an archive of geochemical data collected from 1988 to 2014 to determine the sources and occurrence of groundwater methane in the Denver-Julesburg Basin of northeastern Colorado. This 60,000-km2 region has a 60-y-long history of hydraulic fracturing, with horizontal drilling and high-volume hydraulic fracturing beginning in 2010. Of 924 sampled water wells in the basin, dissolved methane was detected in 593 wells at depths of 20–190 m. Based on carbon and hydrogen stable isotopes and gas molecular ratios, most of this methane was microbially generated, likely within shallow coal seams. A total of 42 water wells contained thermogenic stray gas originating from underlying oil and gas producing formations. Inadequate surface casing and leaks in production casing and wellhead seals in older, vertical oil and gas wells were identified as stray gas migration pathways. The rate of oil and gas wellbore failure was estimated as 0.06% of the 54,000 oil and gas wells in the basin (lower estimate) to 0.15% of the 20,700 wells in the area where stray gas contamination occurred (upper estimate) and has remained steady at about two cases per year since 2001. These results show that wellbore barrier failure, not high-volume hydraulic fracturing in horizontal wells, is the main cause of thermogenic stray gas migration in this oil- and gas-producing basin. PMID:27402747

Noble Gas Signatures in Snow: a New Experimental Investigation.

NASA Astrophysics Data System (ADS)

Amalberti, J.; Hall, C. M.; Castro, C.

2016-12-01

Dissolved noble gases in groundwater (He, Ne, Ar, Kr, and Xe) have been widely used to improve our knowledge of surface and groundwater dynamics. However, a recent rainwater study [1] recorded noble gas concentration anomalies originating from conditions at high altitude. Potential anomaly sources might include fog, orographic rain, synoptic rain and snow, depending on the region considered. Here, we outline a methodology for measuring noble gases in freshly collected snow samples. Their fine-grained nature leads to significant experimental challenges. Overall, our results (Fig. 1) show that snow has elevated He concentrations with depleted concentrations of all other noble gases. Similar results have been recorded in ice [2, 3]. In addition, our results show relatively homogeneous (< 14%) He and Ne concentrations while Ar, Kr and Xe display large concentration variability (> 80%). These observations led us to investigate the structure of snow and potential host-sites (available empty space) within the crystal structure. Noble gases are chemically inert and do not form bonds that could affect the ice crystal structure. Therefore, host-sites control the solubility of each noble gas. Our results show that He and Ne, which are known to have small atomic radii, are likely dissolved into the ice/snow crystal lattice, while heavy noble gas (Ar, Kr and Xe) are likely accommodated into defects. Consequently, smaller variability recorded in light noble gases, may result from He and Ne being hosted within the crystal lattice, whereas heavy noble gases rely on the presence of defects, which may randomly appear within the structure during snow formation. These new results can be used to better constrain the source of ground ice [3], groundwater systems and to investigate the structural transition mechanisms from snow to firn and ice. Figure 1: Noble gas concentrations (C) in snow (filled circles symbols) and ice (half-filled square symbols) normalized to air saturated water (ASW). [1] Warrier, et al., (2013), Geophys. Res. Lett., 40, 3248-3252. [2] Malone et al., (2010), EPSL, 289, 112-122. [3] Utting et a., (2016), Quat. Res., 85, 117-184.

Marcellus and mercury: Assessing potential impacts of unconventional natural gas extraction on aquatic ecosystems in northwestern Pennsylvania.

PubMed

Grant, Christopher J; Weimer, Alexander B; Marks, Nicole K; Perow, Elliott S; Oster, Jacob M; Brubaker, Kristen M; Trexler, Ryan V; Solomon, Caroline M; Lamendella, Regina

2015-01-01

Mercury (Hg) is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain with potentially harmful effects on ecosystems and human health. Twenty-four streams remotely located in forested watersheds in northwestern PA containing naturally reproducing Salvelinus fontinalis (brook trout), were targeted to gain a better understanding of how Marcellus shale natural gas exploration may be impacting water quality, aquatic biodiversity, and Hg bioaccumulation in aquatic ecosystems. During the summer of 2012, stream water, stream bed sediments, aquatic mosses, macroinvertebrates, crayfish, brook trout, and microbial samples were collected. All streams either had experienced hydraulic fracturing (fracked, n = 14) or not yet experienced hydraulic fracturing (non-fracked, n = 10) within their watersheds at the time of sampling. Analysis of watershed characteristics (GIS) for fracked vs non-fracked sites showed no significant differences (P > 0.05), justifying comparisons between groups. Results showed significantly higher dissolved total mercury (FTHg) in stream water (P = 0.007), lower pH (P = 0.033), and higher dissolved organic matter (P = 0.001) at fracked sites. Total mercury (THg) concentrations in crayfish (P = 0.01), macroinvertebrates (P = 0.089), and predatory macroinvertebrates (P = 0.039) were observed to be higher for fracked sites. A number of positive correlations between amount of well pads within a watershed and THg in crayfish (r = 0.76, P < 0.001), THg in predatory macroinvertebrates (r = 0.71, P < 0.001), and THg in brook trout (r = 0.52, P < 0.01) were observed. Stream-water microbial communities within the Deltaproteobacteria also shared a positive correlation with FTHg and to the number of well pads, while stream pH (r = -0.71, P < 0.001), fish biodiversity (r = -0.60, P = 0.02), and macroinvertebrate taxa richness (r = -0.60, P = 0.01) were negatively correlated with the number of well pads within a watershed. Further investigation is needed to better elucidate relationships and pathways of observed differences in stream water chemistry, biodiversity, and Hg bioaccumulation, however, initial findings suggest Marcellus shale natural gas exploration is having an effect on aquatic ecosystems.

Deactivation of Oxidation Catalysts

DTIC Science & Technology

1991-05-01

used, with potassium sulfate on a silica support, in the commercial production of sulfuric acid (Satterfield, 1980). It also exhibits some activity...of 0.1 N sulfuric acid and the second contained 25 cc of 0.1 N sodium hydroxide. The effluent gases were passed through the impingers for 15 minutes... acid medium, only hydrogen chloride dissolves in the sulfuric acid . The chlorine in the effluent gas then dissolves in the sodium hydroxide. Knowing the

Potential exposure of larval and juvenile delta smelt to dissolved pesticides in the Sacramento-San Joaquin Delta, California

USGS Publications Warehouse

Kuivila, K.M.; Moon, G.E.

2004-01-01

The San Francisco Estuary is critical habitat for delta smelt Hypomesus transpacificus, a fish whose abundance has declined greatly since 1983 and is now listed as threatened. In addition, the estuary receives drainage from the Central Valley, an urban and agricultural region with intense and diverse pesticide usage. One possible factor of the delta smelt population decline is pesticide toxicity during vulnerable larval and juvenile stages, but pesticide concentrations are not well characterized in delta smelt spawning and nursery habitat. The objective of this study was to estimate the potential exposure of delta smelt during their early life stages to dissolved pesticides. For 3 years (1998-2000), water samples from the Sacramento-San Joaquin Delta were collected during April-June in coordination with the California Department of Fish and Game's delta smelt early life stage monitoring program. Samples were analyzed for pesticides using solid-phase extraction and gas chromatography/mass spectrometry. Water samples contained multiple pesticides, ranging from 2 to 14 pesticides in each sample. In both 1999 and 2000, elevated concentrations of pesticides overlapped in time and space with peak densities of larval and juvenile delta smelt. In contrast, high spring outflows in 1998 transported delta smelt away from the pesticide sampling sites so that exposure could not be estimated. During 2 years, larval and juvenile delta smelt were potentially exposed to a complex mixture of pesticides for a minimum of 2-3 weeks. Although the measured concentrations were well below short-term (96-h) LC50 values for individual pesticides, the combination of multiple pesticides and lengthy exposure duration could potentially have lethal or sublethal effects on delta smelt, especially during early larval development.

A Demonstration of Acid Rain

ERIC Educational Resources Information Center

Fong, Man Wai

2004-01-01

A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

Mass Transfer from Gas Bubbles to Impinging Flow of Biological Fluids with Chemical Reaction

PubMed Central

Yang, Wen-Jei; Echigo, R.; Wotton, D. R.; Ou, J. W.; Hwang, J. B.

1972-01-01

The rates of mass transfer from a gas bubble to an impinging flow of a biological fluid such as whole blood and plasma are investigated analytically and experimentally. Gases commonly found dissolved in body fluids are included. Consideration is given to the effects of the chemical reaction between the dissolved gas and the liquid on the rate of mass transfer. Through the application of boundary layer theory the over-all transfer is found to be Sh/(Re)1/2 = 0.845 Sc1/3 in the absence of chemical reaction, and Sh/(Re) 1/2 = F′ (0) in the presence of chemical reaction, where Sh, Re, and Sc are the Sherwood, Reynolds, and Schmidt numbers, respectively, and F′ (0) is a function of Sc and the dimensionless reaction rate constant. Analytical results are also obtained for the bubble lifetime and the bubble radius-time history. These results, which are not incompatible with experimental results, can be applied to predict the dissolution of the entrapped gas emboli in the circulatory system of the human body. PMID:4642218

Enhancement of organic matter degradation and methane gas production of anaerobic granular sludge by degasification of dissolved hydrogen gas.

PubMed

Satoh, Hisashi; Bandara, Wasala M K R T W; Sasakawa, Manabu; Nakahara, Yoshihito; Takahashi, Masahiro; Okabe, Satoshi

2017-11-01

A hollow fiber degassing membrane (DM) was applied to enhance organic matter degradation and methane gas production of anaerobic granular sludge process by reducing the dissolved hydrogen gas (D-H 2 ) concentration in the liquid phase. DM was installed in the bench-scale anaerobic granular sludge reactors and D-H 2 was removed through DM using a vacuum pump. Degasification improved the organic matter degradation efficiency to 79% while the efficiency was 62% without degasification at 12,000mgL -1 of the influent T-COD concentration. Measurement of D-H 2 concentrations in the liquid phase confirmed that D-H 2 was removed by degasification. Furthermore, the effect of acetate concentrations on the organic matter degradation efficiency was investigated. At acetate concentrations above 3gL -1 , organic matter degradation deteriorated. Degasification enhanced the propionate and acetate degradation. These results suggest that degasification reduced D-H 2 concentration and volatile fatty acids concentrations, prevented pH drop, and subsequent enhanced organic matter degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Argon concentration time-series as a tool to study gas dynamics in the hyporheic zone.

PubMed

Mächler, Lars; Brennwald, Matthias S; Kipfer, Rolf

2013-07-02

The oxygen dynamics in the hyporheic zone of a peri-alpine river (Thur, Switzerland), were studied through recording and analyzing the concentration time-series of dissolved argon, oxygen, carbon dioxide, and temperature during low flow conditions, for a period of one week. The argon concentration time-series was used to investigate the physical gas dynamics in the hyporheic zone. Differences in the transport behavior of heat and gas were determined by comparing the diel temperature evolution of groundwater to the measured concentration of dissolved argon. These differences were most likely caused by vertical heat transport which influenced the local groundwater temperature. The argon concentration time-series were also used to estimate travel times by cross correlating argon concentrations in the groundwater with argon concentrations in the river. The information gained from quantifying the physical gas transport was used to estimate the oxygen turnover in groundwater after water recharge. The resulting oxygen turnover showed strong diel variations, which correlated with the water temperature during groundwater recharge. Hence, the variation in the consumption rate was most likely caused by the temperature dependence of microbial activity.

Determination of the delta(15N/14N)of Ammonium (NH4+) in Water: RSIL Lab Code 2898

USGS Publications Warehouse

Hannon, Janet E.; Böhlke, John Karl

2008-01-01

The purpose of the technique described by Reston Stable Isotope Laboratory (RSIL) lab code 2898 is to determine the N isotopic composition, delta(15N/14N), abbreviated as d15N, of ammonium (NH4+) in water (freshwater and saline water). The procedure involves converting dissolved NH4+ into NH3 gas by raising the pH of the sample to above 9 with MgO and subsequently trapping the gas quantitatively as (NH4)2SO4 on a glass fiber (GF) filter. The GF filter is saturated with NaHSO4 and pressure sealed between two gas-permeable polypropylene filters. The GF filter 'sandwich' floats on the surface of the water sample in a closed bottle. NH3 diffuses from the water through the polypropylene filter and reacts with NaHSO4, forming (NH4)2SO4 on the GF filter. The GF filter containing (NH4)2SO4 is dried and then combusted with a Carlo Erba NC 2500 elemental analyzer (EA), which is used to convert total nitrogen in a solid sample into N2 gas. The EA is connected to a continuous-flow isotope-ratio mass spectrometer (CF-IRMS), which determines the relative difference in ratios of the amounts of the stable isotopes of nitrogen (15N and 14N) of the product N2 gas and a reference N2 gas. The filters containing the samples are compressed in tin capsules and loaded into a Costech Zero-Blank Autosampler on the EA. Under computer control, samples then are dropped into a heated reaction tube that contains an oxidant, where combustion takes place in a He atmosphere containing an excess of O2 gas. To remove S-O gases produced from the NaHSO4, a plug of Ag-coated Cu wool is inserted at the bottom of the reaction tube. Combustion products are transported by a He carrier through a reduction furnace to remove excess O2, toconvert all nitrogen oxides to N2, and to remove any remaining S-O gases. The gases then pass through a drying tube to remove water. The gas-phase products, mainly N2 and a small amount of background CO2, are separated by a gas chromatograph (GC). The gas is then introduced into the IRMS through a Finnigan ConFlo II interface. The ConFlo II interface is used to introduce not only sample into the IRMS but also N2 reference gas and He for sample dilution. The flash combustion is quantitative, so no isotopic fractionation is involved. The IRMS is a Finnigan Delta V CF-IRMS with 10 cups and is capable of detecting ion beams with mass/charge (m/z) 28, 29, 30. The ion beams from N2 are as follows: m/z 28 = 14N14N, m/z 29 = 14N15N, and m/z 30 = 15N15N. The ion beam with m/z 30 also represents 14N16O, which may indicate contamination or incomplete reduction.

The Biogeochemistry of Seattle's Urban Streams

NASA Astrophysics Data System (ADS)

Yonemura, R.

2016-12-01

Urban development is underway at an unprecedented pace in the city of Seattle, WA. What were once productive salmon spawning ecosystems are now highly altered ecosystems that reflect the impacts of human land-use change. However, the impact that these changes have had on the carbon biogeochemistry have not been studied. We investigate the biogeochemical properties over time of two urban streams in Seattle; Ravenna Creek, an urban park and closed network, and Thornton Creek, a recently day-lighted and restored stream network. We conducted a longitudinal sampling along each of these creeks from their headwaters down to their confluences with Lake Washington. Our data suggest that these systems are supersaturated in both dissolved carbon dioxide and dissolved methane. Preliminary results reveal that carbon dioxide and methane are both highest at the end of Ravenna Creek located on the surface of a preexisting landfill. The highest carbon dioxide and methane levels on Thornton Creek are located at the uppermost site and the site directly below a golf course. These findings suggest that local land-use has an impact on the concentrations of dissolved gases in the surrounding water bodies with implications for urban streams as localized sources of carbon dioxide and methane to the atmosphere. Additional data on nutrients and stream metabolism will highlight the consistency of these gas concentrations over time, and provide an additional indicator into the health of these urban systems.

Geology and ground-water resources of Winkler County, Texas

USGS Publications Warehouse

Garza, Sergio; Wesselman, John B.

1963-01-01

The chemical quality of the water in the principal aquifers is generally acceptable for industry and for public supply. About two-thirds of the samples collected from fresh-water wells had a dissolved-solids content of less than 1,000 ppm (parts per million) ; however, some samples in a few areas were hard and were high in fluoride and silica. Samples from wells in polluted areas contained dissolved solids ranging from about 1,400 to 71,100 ppm. Two comprehensive analyses of water samples from the Rustler formation showed a dissolved-solids content of 18,400 ppm. and 157,000 ppm. In most of the water produced with the oil in the Hendrick oil field, the content of dissolved solids ranged from about 4,000 to about 10,000 ppm. The water produced with the oil in the rest of the oil fields in Winkler County was mainly brine.

Sources, extent and history of methane seepage on the continental shelf off northern Norway

NASA Astrophysics Data System (ADS)

Sauer, Simone; Lepland, Aivo; Chand, Shyam; Schubert, Carsten J.; Eichinger, Florian; Knies, Jochen

2014-05-01

Active natural hydrocarbon gas seepage was recently discovered in the Hola area on the continental shelf off Vesterålen, northern Norway. We conducted acoustic and geochemical investigations to assess the modern and past extent, source and pathways of the gas seepage . Water column echosounder surveys showed bubble plumes up to several tens of metres above the seafloor. Analyses of dissolved methane in the water column indicated slightly elevated concentrations (50 nM) close to the seafloor. To identify fluxes and origin of methane in the sediments we analysed sediment pore water chemistry, the isotopic composition of methane and of dissolved inorganic carbon (d13CCH4, d2HCH4, d13CDIC) in three closely spaced (

Solution and shock-induced exsolution of argon in vitreous carbon

NASA Technical Reports Server (NTRS)

Gazis, Carey; Ahrens, Thomas J.

1991-01-01

To add to the knowledge of noble gas solution and exsolution in carbonaceus material, experiments were performed on vitreous carbon. Ar-rich vitreous carbon samples were prepared under vapor-saturated conditions using argon as the pressurizing medium. Solubility data were obtained for temperatures of 773 to 973 K and pressures of 250 to 1500 bars. Up to 7 wt pct Ar was dissolved in the carbon. The solubility data were compared to a thermodynamic model of argon atoms dissolving into a fixed population of 'holes' in the carbon. Two variations of the model yielded estimates of the enthalpy of solution of Ar in vitreous carbon equal to about -4700 cal/mole. Preliminary shock experiments showed that 28 percent of the total argon was released by driving 4 GPa shocks into the argon-rich carbon. It was demonstrated that shock-induced argon loss is not simply caused by the impact-induced diminution of grain size. The present value of shock pressure required for partial impact devolatilization of Ar from carbon is below the range (5-30 GPa) at which H2O is released from phyllosilicates.

Carbon dioxide degassing at the groundwater-stream-atmosphere interface: isotopic equilibration and hydrological mass balance in a sandy watershed

NASA Astrophysics Data System (ADS)

Deirmendjian, Loris; Abril, Gwenaël

2018-03-01

Streams and rivers emit significant amounts of CO2 and constitute a preferential pathway of carbon transport from terrestrial ecosystems to the atmosphere. However, the estimation of CO2 degassing based on the water-air CO2 gradient, gas transfer velocity and stream surface area is subject to large uncertainties. Furthermore, the stable isotope signature of dissolved inorganic carbon (δ13C-DIC) in streams is strongly impacted by gas exchange, which makes it a useful tracer of CO2 degassing under specific conditions. For this study, we characterized the annual transfers of dissolved inorganic carbon (DIC) along the groundwater-stream-river continuum based on DIC concentrations, stable isotope composition and measurements of stream discharges. We selected a homogeneous, forested and sandy lowland watershed as a study site, where the hydrology occurs almost exclusively through drainage of shallow groundwater (no surface runoff). We observed the first general spatial pattern of decreases in pCO2 and DIC and an increase in δ13C-DIC from groundwater to stream orders 1 and 2, which was due to the experimentally verified faster degassing of groundwater 12C-DIC compared to 13C-DIC. This downstream enrichment in 13C-DIC could be modelled by simply considering the isotopic equilibration of groundwater-derived DIC with the atmosphere during CO2 degassing. A second spatial pattern occurred between stream orders 2 and 4, consisting of an increase in the proportion of carbonate alkalinity to the DIC accompanied by the enrichment of 13C in the stream DIC, which was due to the occurrence of carbonate rock weathering downstream. We could separate the contribution of these two processes (gas exchange and carbonate weathering) in the stable isotope budget of the river network. Thereafter, we built a hydrological mass balance based on drainages and the relative contribution of groundwater in streams of increasing order. After combining with the dissolved CO2 concentrations, we quantified CO2 degassing for each stream order for the whole watershed. Approximately 75% of the total CO2 degassing from the watershed occurred in first- and second-order streams. Furthermore, from stream order 2-4, our CO2 degassing fluxes compared well with those based on stream hydraulic geometry, water pCO2, gas transfer velocity, and stream surface area. In first-order streams, however, our approach showed CO2 fluxes that were twice as large, suggesting that a fraction of degassing occurred as hotspots in the vicinity of groundwater resurgence and was missed by conventional stream sampling.

Biochemical Oxygen Demand and Dissolved Oxygen. Training Module 5.105.2.77.

ERIC Educational Resources Information Center

Kirkwood Community Coll., Cedar Rapids, IA.

This document is an instructional module package prepared in objective form for use by an instructor familiar with the azide modification of the Winkler dissolved oxygen test and the electronic dissolved oxygen meter test procedures for determining the dissolved oxygen and the biochemical oxygen demand of a wastewater sample. Included are…

Investigation of fluorocarbon blowing agents in insulating polymer foams by 19F NMR imaging.

PubMed

Fyfe, C A; Mei, Z; Grondey, H

1996-01-01

Currently, there is no reliable and readily accessible technique with which the distribution and diffusion of blowing agents in rigid insulating foams can be detected and monitored. In this paper, we demonstrate that 19F NMR microscopic imaging together with 19F solid-state MAS NMR spectroscopy is ideally suited for such measurements and yield quantitatively reliable information that will be critical to the development and fabrication of optimized insulating materials with alternative blowing agents. Polystyrene (PS) and polyurethane (PU) foam samples were investigated with the objective of determining quantitatively the amount of blowing agents in the gaseous phase and dissolved in the polymer phase, and to determine and monitor the distribution of the blowing agents in aged foams as a function of time and temperature. The concentrations of the gaseous blowing agents in the cells and dissolved in the solid were simultaneously and quantitatively measured by 19F MAS NMR spectroscopy. An unfaced 1-yr-old PS foam filled with CH3CF2Cl has about 13% of total HCFCs dissolved in the solid; while there is about 24% of HCFCs in the solid of a faced 3-mos-old PU foam filled with CH3CCl2F. The data from 19F NMR imaging demonstrate that the distributions of the blowing agents in an aged foam are quite uniform around the center part (2 cm away from any edge) of a foam board; however, a gradient in blowing agent concentration was found as a function of distance from the initial factory cut edge. The effective diffusion coefficients of the blowing agents can be directly calculated from the imaging data. Quantitative diffusion constants and activation barriers were determined. Additionally, a foam treated with a second blowing agent was monitored with chemical shift selective imaging and the diffusion of the second gas into the foam and the out-diffusion of the original gas were determined.

Evasion of CO2 from streams - the dominant component of the carbon export through the aquatic conduit in a boreal landscape.

PubMed

Wallin, Marcus B; Grabs, Thomas; Buffam, Ishi; Laudon, Hjalmar; Agren, Ånneli; Öquist, Mats G; Bishop, Kevin

2013-03-01

Evasion of gaseous carbon (C) from streams is often poorly quantified in landscape C budgets. Even though the potential importance of the capillary network of streams as C conduits across the land-water-atmosphere interfaces is sometimes mentioned, low-order streams are often left out of budget estimates due to being poorly characterized in terms of gas exchange and even areal surface coverage. We show that evasion of C is greater than all the total dissolved C (both organic and inorganic) exported downstream in the waters of a boreal landscape. In this study evasion of carbon dioxide (CO2 ) from running waters within a 67 km(2) boreal catchment was studied. During a 4 year period (2006-2009) 13 streams were sampled on 104 different occasions for dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). From a locally determined model of gas exchange properties, we estimated the daily CO2 evasion with a high-resolution (5 × 5 m) grid-based stream evasion model comprising the entire ~100 km stream network. Despite the low areal coverage of stream surface, the evasion of CO2 from the stream network constituted 53% (5.0 (±1.8) g C m(-2)  yr(-1) ) of the entire stream C flux (9.6 (±2.4) g C m(-2)  yr(-1) ) (lateral as DIC, DOC, and vertical as CO2 ). In addition, 72% of the total CO2 loss took place already in the first- and second-order streams. This study demonstrates the importance of including CO2 evasion from low-order boreal streams into landscape C budgets as it more than doubled the magnitude of the aquatic conduit for C from this landscape. Neglecting this term will consequently result in an overestimation of the terrestrial C sink strength in the boreal landscape. © 2012 Blackwell Publishing Ltd.

Dissolved methane in the residual basins of the Aral Sea

NASA Astrophysics Data System (ADS)

Izhitskaya, Elena; Zavialov, Peter; Egorov, Alexander

2017-04-01

The state of the Aral Sea has changed significantly since the second half of the 20th century. Due to the level decline the present-day sea consists of the several water bodies: the Large Aral Sea, the Small Aral Sea and Lake Tshchebas. Water balance peculiarities of each basin caused the differences in physical, chemical and biological structure of the ecosystem. Severe salinization of the Large Aral resulted in the increase of water stratification and formation of the anoxic conditions in the bottom layer. According to the field survey of 2002 [Zavialov et al., 2003; Friedrich, Oberhansli, 2004], hydrogen sulfide was detected in the bottom layer of the Large Aral Sea for the first time. Methane formation is the next reaction after sulfate reduction within process of sequential oxidation of organic matter [Break, 1974]. Thus, methane is an important indicator of biogeochemical processes in natural water environments. Besides due to high greenhouse activity of methane study of its emission to the atmosphere is essential for solution of climatological problems [Bazhin, 2000]. The presented study aims to the evaluation of methane dissolved in waters of the Aral region. Measurements of the gas concentration were carried out on surface and vertical profiles, as well as on point stations in 2012, 2013, 2015 and 2016 years in different parts of the sea. Water samples were analyzed by the head-space method with further gas chromatographic determination of methane concentration [Bolshakov, Egorov, 1987]. According to the obtained data, dissolved methane content in the surface waters of the residual basins of the Aral Sea ranges from 12 to 234 nM/l. One of the main results of the research is detection of intensive methane increase in the lower water layer of the Large Aral to 17014 nM/l in central part and to 147316 nM/l in the Chernyshev Bay.

[Application of optimized parameters SVM based on photoacoustic spectroscopy method in fault diagnosis of power transformer].

PubMed

Zhang, Yu-xin; Cheng, Zhi-feng; Xu, Zheng-ping; Bai, Jing

2015-01-01

In order to solve the problems such as complex operation, consumption for the carrier gas and long test period in traditional power transformer fault diagnosis approach based on dissolved gas analysis (DGA), this paper proposes a new method which is detecting 5 types of characteristic gas content in transformer oil such as CH4, C2H2, C2H4, C2H6 and H2 based on photoacoustic Spectroscopy and C2H2/C2H4, CH4/H2, C2H4/C2H6 three-ratios data are calculated. The support vector machine model was constructed using cross validation method under five support vector machine functions and four kernel functions, heuristic algorithms were used in parameter optimization for penalty factor c and g, which to establish the best SVM model for the highest fault diagnosis accuracy and the fast computing speed. Particles swarm optimization and genetic algorithm two types of heuristic algorithms were comparative studied in this paper for accuracy and speed in optimization. The simulation result shows that SVM model composed of C-SVC, RBF kernel functions and genetic algorithm obtain 97. 5% accuracy in test sample set and 98. 333 3% accuracy in train sample set, and genetic algorithm was about two times faster than particles swarm optimization in computing speed. The methods described in this paper has many advantages such as simple operation, non-contact measurement, no consumption for the carrier gas, long test period, high stability and sensitivity, the result shows that the methods described in this paper can instead of the traditional transformer fault diagnosis by gas chromatography and meets the actual project needs in transformer fault diagnosis.

Low temperature dissolution flowsheet for plutonium metal

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

Daniel, W. E.; Almond, P. M.; Rudisill, T. S.

2016-05-01

The H-Canyon flowsheet used to dissolve Pu metal for PuO 2 production utilizes boiling HNO 3. SRNL was requested to develop a complementary dissolution flowsheet at two reduced temperature ranges. The dissolution and H 2 generation rates of Pu metal were investigated using a dissolving solution at ambient temperature (20-30 °C) and for an intermediate temperature of 50-60 °C. Additionally, the testing included an investigation of the dissolution rates and characterization of the off-gas generated from the ambient temperature dissolution of carbon steel cans and the nylon bags that contain the Pu metal when charged to the dissolver.

Thermodynamic properties of gases dissolved in electrolyte solutions.

NASA Technical Reports Server (NTRS)

Tiepel, E. W.; Gubbins, K. E.

1973-01-01

A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

Physical and chemical properties of San Francisco Bay, California, 1980

USGS Publications Warehouse

Ota, Allan Y.; Schemel, L.E.; Hager, S.W.

1989-01-01

The U.S. Geological Survey conducted hydrologic investigations in both the deep water channels and the shallow-water regions of the San Francisco Bay estuarine system during 1980. Cruises were conducted regularly, usually at two-week intervals. Physical and chemical properties presented in this report include temperature , salinity, suspended particulate matter, turbidity, extinction coefficient, partial pressure of CO2, partial pressure of oxygen , dissolved organic carbon, particulate organic carbon, discrete chlorophyll a, fluorescence of photosynthetic pigments, dissolved silica, dissolved phosphate, nitrate plus nitrite, nitrite, ammonium, dissolved inorganic nitrogen, dissolved nitrogen, dissolved phosphorus, total nitrogen, and total phosphorus. Analytical methods are described. The body of data contained in this report characterizes hydrologic conditions in San Francisco Bay during a year with an average rate of freshwater inflow to the estuary. Concentrations of dissolved silica (discrete-sample) ranged from 3.8 to 310 micro-M in the northern reach of the bay, whereas the range in the southern reach was limited to 63 to 150 micro-M. Concentrations of phosphate (discrete-sample) ranged from 1.3 to 4.4 micro-M in the northern reach, which was narrow in comparison with that of 2.2 to 19.0 micro-M in the southern reach. Concentrations of nitrate plus nitrite (discrete-sample) ranged from near zero to 53 micro-M in the northern reach, and from 2.3 to 64 micro-M in the southern reach. Concentrations of nitrite (discrete-sample) were low in both reaches, exhibiting a range from nearly zero to approximately 2.3 micro-M. Concentrations of ammonium (discrete-sample) ranged from near zero to 14.2 micro-M in the northern reach, and from near zero to 8.3 micro-M in the southern reach. (USGS)

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability.

PubMed

Turner, Andrew; Mawji, Edward

2005-05-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D(ow), ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant (<1%) to octanol extraction. Distribution coefficients defining the concentration ratio of octanol-soluble particle-bound metal to octanol-soluble dissolved metal were in the range 10(3.3)-10(5.3)mlg(-1). The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision.

The spatial variability of water chemistry and DOC in bog pools: the importance of slope position, diurnal turnover and pool type

NASA Astrophysics Data System (ADS)

Holden, Joseph; Turner, Ed; Baird, Andy; Beadle, Jeannie; Billett, Mike; Brown, Lee; Chapman, Pippa; Dinsmore, Kerry; Dooling, Gemma; Grayson, Richard; Moody, Catherine; Gee, Clare

2017-04-01

We have previously shown that marine influence is an important factor controlling regional variability of pool water chemistry in blanket peatlands. Here we examine within-site controls on pool water chemistry. We surveyed natural and artificial (restoration sites) bog pools at blanket peatland sites in northern Scotland and Sweden. DOC, pH, conductivity, dissolved oxygen, temperature, cations, anions and absorbance spectra from 220-750nm were sampled. We sampled changes over time but also conducted intensive spatial surveys within individual pools and between pools on the same sampling days at individual study sites. Artificial pools had significantly greater DOC concentrations and different spectral absorbance characteristics when compared to natural pools at all sites studied. Within-pool variability in water chemistry tended to be small, even for very large pools ( 400 m2), except where pools had a layer of loose, mobile detritus on their beds. In these instances rapid changes took place between the overlying water column and the mobile sediment layer wherein dissolved oxygen concentrations dropped from values of around 12-10 mg/L to values less than 0.5 mg/L over just 2-3 cm of the depth profile. Such strong contrasts were not observed for pools which had a hard peat floor and which lacked a significant detritus layer. Strong diurnal turnover occurred within the pools on summer days, including within small, shallow pools (e.g. < 30 cm deep, 1 m2 area). For many pools on these summer days there was an evening spike in dissolved oxygen concentrations which originated at the surface and was then cycled downwards as the pool surface waters cooled. Slope location was a significant control on several pool water chemistry variables including pH and DOC concentration with accumulation (higher concentrations) in pools that were located further downslope in both natural and artificial pool systems. These processes have important implications for our interpretation of water chemistry and gas flux data from pool systems, how we design our sampling strategies and how we upscale results.

Function of peatland located on secondary transformed peat-moorsh soils on groundwater purification processes and the elution of soil organic matter

NASA Astrophysics Data System (ADS)

Szczepański, M.; Szajdak, L.; Bogacz, A.

2009-04-01

The investigation of peatland is used to show the water quality functioning with respect to different forms of nitrogen and carbon. The purification of ground water by the transect of 4.5 km long consisting organic soils (peat-moorsh soils) was estimated. This transect is located in the Agroecological Landscape Park in Turew, 40 km South-West of Poznan, West Polish Lowland. There is this transect along Wyskoć ditch. pH, the contents of total and dissolved organic carbon, total nitrogen, N-NO3-, N-NH4+ was measured. Additionally C/N factors of peats were estimated. The investigation has shown the impact of the peatland located on the secondary transformed peat - moorsh soils on the lowering of total nitrogen, ammonium, and nitrates as well as total and dissolved organic carbon in ground water. Peat-moorsh soils were described and classified according to Polish hydrogenic soil classification and World Reference Base Soil Notation. There are these investigated points along to Wyskoc ditch. Two times a month during entire vegetation season the following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo: samples of peat, from the depth of 0-20 cm, samples of water from the ditch, samples of ground water from wells established for this investigation. Samples of peat-moorsh soils were collected at the depth 0-20 cm. Soils were sampled two times a month from 10 sites of each site. Samples were air dried and crushed to pass a 1 mm-mesh sieve. These 10 sub-samples were mixed for the reason of preparing a "mean sample", which used for the determination of pH (in 1M KCl), dissolved organic carbon (DOC), total organic carbon (TOC), total nitrogen (Ntotal), and N-NO3- as well as N-NH4+. In water from Wyskoć ditch pH, Ntotal, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) was measured. Ground water samples were collected from four wells established for this investigation. The water was filtered by the middle velocity separation and pH, N-total, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) ware measured. Peatland located on the secondary transformed peat - moorsh soils has revealed the lowering in ground water: nitrates 38.5%, N-organic 10%, N-total 24.5%, ammonium 38.7%, dissolved total carbon 33.1%, dissolved total inorganic carbon 10%, and dissolved organic carbon 57.5%. The dissolution of soil organic matter from peat-moorsh soils in broad range of pH and ionic strength was investigated. The rates of the reaction were calculated from the kinetics of first order reaction model. The investigations have shown the impact of the properties of secondary transformed peat-moorsh soils on the rates of the dissolution of organic matter.

Potential Environmental Impacts of CO2 Storage in Sedimentary Basins: Results From the Frio Brine Test, Texas, USA

NASA Astrophysics Data System (ADS)

Kharaka, Y. K.; Cole, D. R.; Hovorka, S. D.; Phelps, T. J.; Nance, S.

2006-12-01

Deep saline aquifers in sedimentary basins, including depleted petroleum reservoirs, provide advantageous locations close to major anthropogenic sources of CO2 and potential capacity for the storage of huge volumes of this greenhouse gas. To investigate the potential for the long-term storage of CO2 in such aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick "C" sandstone section of the Frio Formation, a regional saline aquifer in the U.S. Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m updip showed a Na-Ca-Cl type brine with 93,000 mg/L TDS at near saturation with CH4 at reservoir conditions; gas analyses show CH4 comprised ~95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5 to 5.7), pronounced increases in alkalinity (100 to 3000 mg/L as HCO3) and in Fe (30 to 1100 mg/L), and significant shifts in the isotopic compositions of H2O, Sr, DIC, and CH4. These data coupled with geochemical modeling indicate rapid dissolution of minerals, especially calcite and iron oxyhydroxides caused by lowered pH (~3.0 initially) of the brine in contact with the injected supercritical CO2. These geochemical parameters, together with perfluorocarbon tracer gases (PFTs) proved effective in mapping the distribution and interactions of the injected CO2 in the Frio "C". They are being used to track the migration of the injected CO2 into the local shallow groundwater and into the overlying Frio "B", comprised of a 4-m-thick sandstone bed and separated from the "C" by ~15 m of shale, muddy sandstone and siltstone beds. Results obtained to date from the four monitoring groundwater wells perforated (26-29 m) in the Beaumont aquifer show some temporal chemical changes. These changes, however, are tentatively attributed to natural variations and recharge events caused by the construction of a mud pit at the site, and not to leakage through the Anahuac Formation, the regional cap rock comprised of thick (~80 m) and impermeable marine shale and mudstone beds. Data on brine and gas compositions of samples obtained from the Frio "B" 6 mo after injection show significant CO2 (2.9% compared with 0.3% CO2 in dissolved gas) migration into the "B" sandstone. Except for two PFT tracer gases explained by desorption, results of samples collected 15 mo after injection show no other indications of injected CO2 in the "B" sandstone. The initial presence of injected CO2 near the observation well shows migration through the intervening beds or more likely a leakage through the remedial cement around the casing of a 50- year old well. These results highlight the importance of investigating the integrity of cement seals, especially in nearby abandoned wells, prior to the injection of large quantities of reactive and buoyant CO2.

TOGA: A TOUGH code for modeling three-phase, multi-component, and non-isothermal processes involved in CO 2-based Enhanced Oil Recovery

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

Pan, Lehua; Oldenburg, Curtis M.

TOGA is a numerical reservoir simulator for modeling non-isothermal flow and transport of water, CO 2, multicomponent oil, and related gas components for applications including CO 2-enhanced oil recovery (CO 2-EOR) and geologic carbon sequestration in depleted oil and gas reservoirs. TOGA uses an approach based on the Peng-Robinson equation of state (PR-EOS) to calculate the thermophysical properties of the gas and oil phases including the gas/oil components dissolved in the aqueous phase, and uses a mixing model to estimate the thermophysical properties of the aqueous phase. The phase behavior (e.g., occurrence and disappearance of the three phases, gas +more » oil + aqueous) and the partitioning of non-aqueous components (e.g., CO 2, CH 4, and n-oil components) between coexisting phases are modeled using K-values derived from assumptions of equal-fugacity that have been demonstrated to be very accurate as shown by comparison to measured data. Models for saturated (water) vapor pressure and water solubility (in the oil phase) are used to calculate the partitioning of the water (H 2O) component between the gas and oil phases. All components (e.g., CO 2, H 2O, and n hydrocarbon components) are allowed to be present in all phases (aqueous, gaseous, and oil). TOGA uses a multiphase version of Darcy’s Law to model flow and transport through porous media of mixtures with up to three phases over a range of pressures and temperatures appropriate to hydrocarbon recovery and geologic carbon sequestration systems. Transport of the gaseous and dissolved components is by advection and Fickian molecular diffusion. New methods for phase partitioning and thermophysical property modeling in TOGA have been validated against experimental data published in the literature for describing phase partitioning and phase behavior. Flow and transport has been verified by testing against related TOUGH2 EOS modules and CMG. The code has also been validated against a CO 2-EOR experimental core flood involving flow of three phases and 12 components. Results of simulations of a hypothetical 3D CO 2-EOR problem involving three phases and multiple components are presented to demonstrate the field-scale capabilities of the new code. This user guide provides instructions for use and sample problems for verification and demonstration.« less

Development of a circulation direct sampling and monitoring system for O2 and CO2 concentrations in the gas-liquid phases of shake-flask systems during microbial cell culture.

PubMed

Takahashi, Masato; Sawada, Yoshisuke; Aoyagi, Hideki

2017-08-23

Monitoring the environmental factors during shake-flask culture of microorganisms can help to optimise the initial steps of bioprocess development. Herein, we developed a circulation direct monitoring and sampling system (CDMSS) that can monitor the behaviour of CO 2 and O 2 in the gas-liquid phases and obtain a sample without interrupting the shaking of the culture in Erlenmeyer flasks capped with breathable culture plugs. Shake-flask culturing of Escherichia coli using this set-up indicated that a high concentration of CO 2 accumulated not only in the headspace (maximum ~100 mg/L) but also in the culture broth (maximum ~85 mg/L) during the logarithmic phase (4.5-9.0 h). By packing a CO 2 absorbent in the gas circulation unit of CDMSS, a specialised shake-flask culture was developed to remove CO 2 from the headspace. It was posited that removing CO 2 from the headspace would suppress increases in the dissolved CO 2 concentration in the culture broth (maximum ~15 mg/L). Furthermore, the logarithmic growth phase (4.5-12.0 h) was extended, the U.O.D. 580 and pH value increased, and acetic acid concentration was reduced, compared with the control. To our knowledge, this is the first report of a method aimed at improving the growth of E. coli cells without changing the composition of the medium, temperature, and shaking conditions.

[Rapid determination of 40 pesticide residues in fruits using gas chromatography-mass spectrometry coupled with analyte protectants to compensate for matrix effects].

PubMed

Xu, Xiuli; Zhao, Haixiang; Li, Li; Liu, Hanxia; Ren, Heling; Zhong, Weike

2012-03-01

A gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 40 pesticides in fruits. The effects of adding analyte protectants were evaluated for compensating matrix effects and the impacts on the quantitative results. A new combination of analyte protectants - Polyethylene Glycol 400 (PEG 400) and olive oil combination, which can be dissolved in acetone, was used for the quantitative analysis. The pesticides were extracted from fruit samples with acetonitrile and the extracts were cleaned up using micro-solid phase extraction. A GC-MS method in selective ion monitoring (SIM) mode coupled with large volume injection was finally developed. Using the newly developed analyte protectant combination of PEG 400 and olive oil, a good linearity was obtained in the range of 1 - 200 microg/L with coefficients better than 0.99, and the detection limits were between 0.1 - 3.0 microg/L. The mean recoveries of the pesticides were 75% - 119% with the relative standard deviation values less than 16.6% except for dimethoate. The performance of the analyte protectants was compared with matrix-matched standards calibration curves in terms of quantitative accuracy. The results showed that the method of adding analyte protectants can replace the matrix-matched standard calibration, and can also reduce the sample pretreatment. When the devel- oped method was used for the analysis of apple, peache, orange, banana, grape and other fruit samples, a good matrix compensation effect was achieved, and thus effectively reduced the bad effects of the water-soluble agents to the gas chromatographic column.

Compound-Specific Stable Carbon Isotope Analysis of Low-Concentration Complex Hydrocarbon Mixtures from Natural Gas Hydrate Systems

NASA Astrophysics Data System (ADS)

Plummer, R. E.; Pohlman, J. W.; Coffin, R. B.

2005-12-01

A system has been developed to measure the stable carbon isotope (δ13C) composition of dissolved methane, ethane, and propane from natural sediment samples with headspace concentrations as low as 1 ppm using a modified Thermo Electron Trace gas chromatograph (GC) connected to a Finnigan Delta Plus XP isotope ratio mass spectrometer (IRMS). A cryofocusing inlet was connected to the GC which allows 0.02- to 15.0-ml injections into a 10-ml min-1 He carrier stream. Analytes from the variable-volume injection are focused into a small section of fused silica capillary, which is either empty or packed with Poraplot-Q, depending on the analyte(s) of interest. The analytes are then rapidly desorbed (100°C) onto the GC column (1.8 ml min-1), where they undergo separation, combustion and IRMS detection. The sensitivity of the IRMS was improved by the addition of high resistivity amplifiers so that measurements can be obtained with as little as 7-ng of carbon. The analytical precision (2σ) is less than 0.5‰ for methane analysis and less than 1‰ for ethane and propane analyses. The gases are standardized by tank CO2 which has been referenced to the NIST RM 8560 natural gas standard. The samples require no pretreatment, and can be analyzed rapidly (20 samples/day) and with minimal instrument training. Using this system, we have obtained complete stable carbon isotope ethane profiles from sediment cores from microbial and thermogenic gas hydrate regions on the Northern Cascadia Margin. We were able to differentiate the relative thermal and microbial contributions of the gases; and furthermore, we obtained clear evidence for ethanogenesis and ethane oxidation at depths similar to those where methanogenesis and anaerobic methane oxidation (AOM), respectively, occurred. This system will be utilized to analyze headspace and hydrate gas samples from IODP Leg 311. These data will allow us to fully characterize the thermogenic contributions and trace hydrocarbon biogeochemical cycling of hydrocarbons along the Expedition 311 margin-perpendicular transect.

Organic compounds in produced waters from shale gas wells.

PubMed

Maguire-Boyle, Samuel J; Barron, Andrew R

2014-01-01

A detailed analysis is reported of the organic composition of produced water samples from typical shale gas wells in the Marcellus (PA), Eagle Ford (TX), and Barnett (NM) formations. The quality of shale gas produced (and frac flowback) waters is a current environmental concern and disposal problem for producers. Re-use of produced water for hydraulic fracturing is being encouraged; however, knowledge of the organic impurities is important in determining the method of treatment. The metal content was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Mineral elements are expected depending on the reservoir geology and salts used in hydraulic fracturing; however, significant levels of other transition metals and heavier main group elements are observed. The presence of scaling elements (Ca and Ba) is related to the pH of the water rather than total dissolved solids (TDS). Using gas chromatography mass spectrometry (GC/MS) analysis of the chloroform extracts of the produced water samples, a plethora of organic compounds were identified. In each water sample, the majority of organics are saturated (aliphatic), and only a small fraction comes under aromatic, resin, and asphaltene categories. Unlike coalbed methane produced water it appears that shale oil/gas produced water does not contain significant quantities of polyaromatic hydrocarbons reducing the potential health hazard. Marcellus and Barnett produced waters contain predominantly C6-C16 hydrocarbons, while the Eagle Ford produced water shows the highest concentration in the C17-C30 range. The structures of the saturated hydrocarbons identified generally follows the trend of linear > branched > cyclic. Heterocyclic compounds are identified with the largest fraction being fatty alcohols, esters, and ethers. However, the presence of various fatty acid phthalate esters in the Barnett and Marcellus produced waters can be related to their use in drilling fluids and breaker additives rather than their presence in connate fluids. Halogen containing compounds are found in each of the water samples, and although the fluorocarbon compounds identified are used as tracers, the presence of chlorocarbons and organobromides formed as a consequence of using chlorine containing oxidants (to remove bacteria from source water), suggests that industry should concentrate on non-chemical treatments of frac and produced waters.

Removal of organic compounds from shale gas flowback water.

PubMed

Butkovskyi, Andrii; Faber, Ann-Hélène; Wang, Yue; Grolle, Katja; Hofman-Caris, Roberta; Bruning, Harry; Van Wezel, Annemarie P; Rijnaarts, Huub H M

2018-07-01

Ozonation, sorption to granular activated carbon and aerobic degradation were compared as potential treatment methods for removal of dissolved organic carbon (DOC) fractions and selected organic compounds from shale gas flowback water after pre-treatment in dissolved air flotation unit. Flowback water was characterised by high chemical oxygen demand and DOC. Low molecular weight (LMW) acids and neutral compounds were the most abundant organic fractions, corresponding to 47% and 35% of DOC respectively. Ozonation did not change distribution of organic carbon fractions and concentrations of detected individual organic compounds significantly. Sorption to activated carbon targeted removal of individual organic compounds with molecular weight >115 Da, whereas LMW compounds remained largely unaffected. Aerobic degradation was responsible for removal of LMW compounds and partial ammonium removal, whereas formation of intermediates with molecular weight of 200-350 Da was observed. Combination of aerobic degradation for LMW organics removal with adsorption to activated carbon for removal of non-biodegradable organics is proposed to be implemented between pre-treatment (dissolved air floatation) and desalination (thermal or membrane desalination) steps. Copyright © 2018 Elsevier Ltd. All rights reserved.

Late diagenetic indicators of buried oil and gas

USGS Publications Warehouse

Donovan, Terrence J.; Dalziel, Mary C.

1977-01-01

At least three hydrocarbon seepage mechanisms are interpreted to operate over oil and gas fields. These are: (1) effusion ofh ydrocarbons through inadequate caprocks and along faults and fractures, (2) low-molecular-weight hydrocarbons dissolved in water moving vertically through capping shales as a result of a hydrodynamic or chemical potential drive, and (3) diffusion of gases dissolved in water. Combinations of these mechanisms may also occur. Seeping hydrocarbons are oxidized near the earth's surface, and the resulting carbon dioxide reacts with water producing bicarbonate ions, which combine with calcium and magnesium dissolved in ground waters to yield isotopically distinctive pore-filling carbonate cements and surface rocks. The passage of hydrocarbons and associated compounds such as hydrogen sulfide through surface rocks causes a reducing environment and consequent reduction, mobilization, and loss of iron from iron-bearing minerals commonly resulting in a discoloration. Other metals such as manganese are also mobilized and redistributed. These changes in the physical and chemical properties of surface rocks correlate with the subsurface distribution of petroleum, and potentially can be detected from both airborne and spaceborne platforms.

High-resolution measurement of DMS and volatile organic compounds dissolved in seawater using equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS)

NASA Astrophysics Data System (ADS)

Kameyama, S.; Tanimoto, H.; Inomata, S.; Tsunogai, U.; Ooki, A.; Yokouchi, Y.; Takeda, S.; Obata, H.; Tsuda, A.; Uematsu, M.

2010-12-01

We developed an equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) for high-resolution measurement of multiple volatile organic compounds (VOCs) dissolved in seawater. The equilibration of six VOC species (dimethyl sulfide (DMS), isoprene, propene, acetone, acetaldehyde, and methanol) between seawater and carrier gas, and the response time of the system were evaluated in the laboratory. While isoprene and propene are not in equilibrium associated with slow response time (≈ 15 min) due to low solubility, other species achieve complete equilibrium with overall response time within 2 min under the condition without water droplets on the inner wall of the headspace of the equilibrator. The EI-PTR-MS instrument was deployed during a cruise in the western North Pacific. For DMS and isoprene, comparison of EI-PTR-MS with a membrane tube equilibrator-gas chromatography/mass spectrometry was made, showing generally good agreement. EI-PTR-MS captured temporal variations of dissolved VOCs including small-scale variability, demonstrating the performance of EI-PTR-MS technique for continuous measurement of multiple VOCs in seawater.

High-pressure liquid-monopropellant strand combustion.

NASA Technical Reports Server (NTRS)

Faeth, G. M.

1972-01-01

Examination of the influence of dissolved gases on the state of the liquid surface during high-pressure liquid-monopropellant combustion through the use of a strand burning experiment. Liquid surface temperatures were measured, using fine-wire thermocouples, during the strand combustion of ethyl nitrate, normal propyl nitrate, and propylene glycol dinitrate at pressures up to 81 atm. These measurements were compared with the predictions of a variable-property gas-phase analysis assuming an infinite activation energy for the decomposition reaction. The state of the liquid surface was estimated using a conventional low-pressure phase equilibrium model, as well as a high-pressure version that considered the presence of dissolved combustion-product gases in the liquid phase. The high-pressure model was found to give a superior prediction of measured liquid surface temperatures. Computed total pressures required for the surface to reach its critical mixing point during strand combustion were found to be in the range from 2.15 to 4.62 times the critical pressure of the pure propellant. Computed dissolved gas concentrations at the liquid surface were in the range from 35 to 50% near the critical combustion condition.

Pore Formation During Solidification of Aluminum: Reconciliation of Experimental Observations, Modeling Assumptions, and Classical Nucleation Theory

NASA Astrophysics Data System (ADS)

Yousefian, Pedram; Tiryakioğlu, Murat

2018-02-01

An in-depth discussion of pore formation is presented in this paper by first reinterpreting in situ observations reported in the literature as well as assumptions commonly made to model pore formation in aluminum castings. The physics of pore formation is reviewed through theoretical fracture pressure calculations based on classical nucleation theory for homogeneous and heterogeneous nucleation, with and without dissolved gas, i.e., hydrogen. Based on the fracture pressure for aluminum, critical pore size and the corresponding probability of vacancies clustering to form that size have been calculated using thermodynamic data reported in the literature. Calculations show that it is impossible for a pore to nucleate either homogeneously or heterogeneously in aluminum, even with dissolved hydrogen. The formation of pores in aluminum castings can only be explained by inflation of entrained surface oxide films (bifilms) under reduced pressure and/or with dissolved gas, which involves only growth, avoiding any nucleation problem. This mechanism is consistent with the reinterpretations of in situ observations as well as the assumptions made in the literature to model pore formation.

Mass transfer apparatus and method for separation of gases

DOEpatents

Blount, Gerald C.

2015-10-13

A process and apparatus for separating components of a source gas is provided in which more soluble components of the source gas are dissolved in an aqueous solvent at high pressure. The system can utilize hydrostatic pressure to increase solubility of the components of the source gas. The apparatus includes gas recycle throughout multiple mass transfer stages to improve mass transfer of the targeted components from the liquid to gas phase. Separated components can be recovered for use in a value added application or can be processed for long-term storage, for instance in an underwater reservoir.

Mass transfer apparatus and method for separation of gases

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

Blount, Gerald C.; Gorensek, Maximilian Boris; Hamm, Luther L.

A process and apparatus for separating components of a source gas is provided in which more soluble components of the source gas are dissolved in an aqueous solvent at high pressure. The system can utilize hydrostatic pressure to increase solubility of the components of the source gas. The apparatus includes gas recycle throughout multiple mass transfer stages to improve mass transfer of the targeted components from the liquid to gas phase. Separated components can be recovered for use in a value added application or can be processed for long-term storage, for instance in an underwater reservoir.

DISSOLVED GAS TRANSPORT IN THE PRESENCE OF A TRAPPED GAS PHASE: DEVELOPMENT AND LABORATORY TESTING OF A TWO-DIMENSIONAL KINETIC MODEL. (R825689C012)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

DIFFUSIVE EXCHANGE OF GASEOUS POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS ACROSS THE AIR-WATER INTERFACE OF THE CHESAPEAKE BAY. (R825245)

EPA Science Inventory

Dissolved and gas-phase concentrations of nine polycyclic aromatic hydrocarbons and 46 polychlorinated biphenyl congeners were measured at eight sites on the Chesapeake Bay at four different times of the year to estimate net diffusive air-water gas exchange rates. Gaseous PAHs ar...

Effect of depletion rate on solution gas drive in shale

NASA Astrophysics Data System (ADS)

Zhang, Mingshan; Sang, Qian; Gong, Houjian; Li, Yajun; Dong, Mingzhe

2018-01-01

Solution gas drive process has been studied extensively in sand rocks and heavy oil reservoirs for a long time. Oil recovery is affected by several factors, such as depletion rate, initial GOR (gas oil ratio), oil viscosity, and temperature and so on. Before the solution gas drive tests, elastic drive without dissolved gas was carried out as a reference, which shows a limited oil recovery. Solution gas drive experiments were conducted in shale to study oil recovery with various depletion rates. Results show that oil recovery increases with the decrease of depletion rates because of the low permeability and desorption of methane.

Pore fluid geochemistry from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

USGS Publications Warehouse

Torres, M.E.; Collett, T.S.; Rose, K.K.; Sample, J.C.; Agena, W.F.; Rosenbaum, E.J.

2011-01-01

The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was drilled and cored from 606.5 to 760.1. m on the North Slope of Alaska, to evaluate the occurrence, distribution and formation of gas hydrate in sediments below the base of the ice-bearing permafrost. Both the dissolved chloride and the isotopic composition of the water co-vary in the gas hydrate-bearing zones, consistent with gas hydrate dissociation during core recovery, and they provide independent indicators to constrain the zone of gas hydrate occurrence. Analyses of chloride and water isotope data indicate that an observed increase in salinity towards the top of the cored section reflects the presence of residual fluids from ion exclusion during ice formation at the base of the permafrost layer. These salinity changes are the main factor controlling major and minor ion distributions in the Mount Elbert Well. The resulting background chloride can be simulated with a one-dimensional diffusion model, and the results suggest that the ion exclusion at the top of the cored section reflects deepening of the permafrost layer following the last glaciation (???100 kyr), consistent with published thermal models. Gas hydrate saturation values estimated from dissolved chloride agree with estimates based on logging data when the gas hydrate occupies more than 20% of the pore space; the correlation is less robust at lower saturation values. The highest gas hydrate concentrations at the Mount Elbert Well are clearly associated with coarse-grained sedimentary sections, as expected from theoretical calculations and field observations in marine and other arctic sediment cores. ?? 2009 Elsevier Ltd.

Gas geochemistry studies at the gas hydrate occurrence in the permafrost environment of Mallik (NWT, Canada)

NASA Astrophysics Data System (ADS)

Wiersberg, T.; Erzinger, J.; Zimmer, M.; Schicks, J.; Dahms, E.; Mallik Working Group

2003-04-01

We present real-time mud gas monitoring data as well as results of noble gas and isotope investigations from the Mallik 2002 Production Research Well Program, an international research project on Gas Hydrates in the Northwest Territories of Canada. The program participants include 8 partners; The Geological Survey of Canada (GSC), The Japan National Oil Corporation (JNOC), GeoForschungsZentrum Potsdam (GFZ), United States Geological Survey (USGS), United States Department of the Energy (USDOE), India Ministry of Petroleum and Natural Gas (MOPNG)/Gas Authority of India (GAIL) and the Chevron-BP-Burlington joint venture group. Mud gas monitoring (extraction of gas dissolved in the drill mud followed by real-time analysis) revealed more or less complete gas depth profiles of Mallik 4L-38 and Mallik 5L-38 wells for N_2, O_2, Ar, He, CO_2, H_2, CH_4, C_2H_6, C_3H_8, C_4H10, and 222Rn; both wells are approx. 1150 m deep. Based on the molecular and and isotopic composition, hydrocarbons occurring at shallow depth (down to ˜400 m) are mostly of microbial origin. Below 400 m, the gas wetness parameter (CH_4/(C_2H_6 + C_3H_8)) and isotopes indicate mixing with thermogenic gas. Gas accumulation at the base of permafrost (˜650 m) as well as δ13C and helium isotopic data implies that the permafrost inhibits gas flux from below. Gas hydrate occurrence at Mallik is known in a depth between ˜890 m and 1100 m. The upper section of the hydrate bearing zone (890 m--920 m) consists predominantly of methane bearing gas hydrates. Between 920 m and 1050 m, concentration of C_2H_6, C_3H_8, and C_4H10 increases due to the occurrence of organic rich sediment layers. Below that interval, the gas composition is similar to the upper section of the hydrate zone. At the base of the hydrate bearing zone (˜1100 m), elevated helium and methane concentrations and their isotopic composition leads to the assumption that gas hydrates act as a barrier for gas migration from below. In mud gas samples from the hydrate zone, the concentrations of all noble gases are lower than in air. Using Ne as a tracer for air contamination, the air-normalized abundances of Ar, Ke and Xe in those samples increase with their mass. Non-atmospheric elemental ratios of the heavier noble gases are most possible the result of elemental fractionation during hydrate formation.

Gas Transfer Controls Carbon Limitation During Biomass Production by Marine Microalgae.

PubMed

Tamburic, Bojan; Evenhuis, Christian R; Suggett, David J; Larkum, Anthony W D; Raven, John A; Ralph, Peter J

2015-08-24

This study presents the first in-depth analysis of CO2 limitation on the biomass productivity of the biofuel candidate marine microalga Nannochloropsis oculata. Net photosynthesis decreased by 60% from 125 to 50 μmol O2 L(-1)h(-1) over a 12 h light cycle as a direct result of carbon limitation. Continuous dissolved O2 and pH measurements were used to develop a detailed diurnal mechanism for the interaction between photosynthesis, gas exchange and carbonate chemistry in the photo-bioreactor. Gas exchange determined the degree of carbon limitation experienced by the algae. Carbon limitation was confirmed by delivering more CO2 , which increased net photosynthesis back to its steady-state maximum. This study highlights the importance of maintaining replete carbon concentrations in photo-bioreactors and other culturing facilities, either by constant pH operation or preferably by designing a feedback loop based on the dissolved O2 concentration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling nonclassical heterogeneous bubble nucleation from cellulose fibers: application to bubbling in carbonated beverages.

PubMed

Liger-Belair, Gérard; Voisin, Cédric; Jeandet, Philippe

2005-08-04

In this paper, the kinetics of CO(2) bubble nucleation from tiny gas pockets trapped inside cellulose fibers immersed in a glass of champagne were investigated, in situ, from high-speed video recordings. Taking into account the diffusion of CO(2)-dissolved molecules from the liquid bulk to the gas pocket, a model was derived which enabled us to connect the kinetics of bubble nucleation with both fiber and liquid parameters. Convection was found to play a major role in this process. The boundary layer around the gas pocket where a gradient of CO(2)-dissolved molecules exists was also indirectly approached and found to be in the order of 10-20 mum. Because most of the particles adsorbed on the wall of a container or vessel free from any particular treatment are also believed to be cellulose fibers coming from the surrounding air, the results of this paper could be indeed extended to the more general field of nonclassical heterogeneous bubble nucleation from supersaturated liquids.

Fingerprinting Deepwater Horizon Oil in the northern Gulf of Mexico using biomarkers and Gas Chromatography-Triple Quadrupole Mass Spectrometry (GC/MS/MS)

NASA Astrophysics Data System (ADS)

Adhikari, P. L.; Overton, E. B.; Maiti, K.; Wong, R. L.

2016-02-01

Petroleum biomarkers such as hopanes, steranes, and triaromatic steroids are more persistent than alkanes and aromatic compounds. Thus, they are often used to track spilled oil in the environments and as a proxy for weathering processes. The present study utilizes water samples, suspended and sinking particles, and seafloor sediments collected during 2011-2013 from various locations of the northern Gulf of Mexico with wide range of contaminated oil for Deepwater Horizon (DWH) oil fingerprinting. The MC252 source oil along with the samples collected in this study were analyzed using a gas chromatography coupled with a triple quadrupole mass spectrometry (GC/MS/MS) in Multiple Reaction Monitoring (MRM) mode and the results were compared with results from commonly used GC/MS selective ion monitoring (SIM) method. The results indicate that the MRM method separates interfering ions from interfering compounds and can be a powerful analytical strategy for a reliable identification and determination of trace levels of biomarkers in complex matrices. Source indicators such as the MRM fragment ion chromatograms of the biomarkers and their diagnostic ratios in samples were compared with the MC252 source oil. The preliminary results show that the biomarkers were below detection limits in dissolved samples. However, in few particulate and seafloor sediment samples, primarily from the immediate vicinity of the Macondo wellhead, contained their patterns. The results also illustrate that these biomarker compounds have been weathered within 1-3 years following the oil spill, and their DWH oil signature in some of these samples reflects this weathering.

Microbial Oxidation of Natural Gas in a Plume Emanating from the Coal Oil Point Seep Field

NASA Astrophysics Data System (ADS)

Mendes, S. D.; Valentine, D. L.; Perez, C.; Scarlett, R.

2012-12-01

The hydrocarbon seep field at Coal Oil Point, off the coast of Santa Barbara, California, releases > 1010 g of thermogenic natural gas each year. Gases emitted from Coal Oil Point include methane, ethane, propane, and butane, which are atmospheric pollutants and greenhouse gases. Even though the seeps are at water depths of only 5-80 m, much of the gas dissolves and contributes to a plume that is transported by ocean currents. While hydrocarbons can support bacterial respiration, resulting in the removal of hydrocarbon gas from the plume, the time-scale for the bacterial respiratory response is unconstrained. To track hydrocarbon respiration 3H-ethane, propane, and butane were synthesized using Grignard reagents and tritiated water with yields of >70% and applied as tracers to samples up- and down-current from the seeps at Coal Oil Point. Validation experiments conducted in September 2011 aboard the R/V Atlantis show that 3H-labeled tracers are an order of magnitude more sensitive than previous methods using stable carbon isotopes (Valentine et. al 2010), making this technique preferable in natural systems. Application of the tracers concurrent with plume tracking in July-August 2012 show ethane, propane, and butane consumption are readily inducible on a timescale of days.

Rapid nondestructive spectrometric measurement of temperature-dependent gas-liquid solubility equilibria.

PubMed

Ma, Jian; Dasgupta, Purnendu K; Yang, Bingcheng

2011-02-01

Gas-liquid solubility equilibria (Henry's Law behavior) are of basic interest to many different areas. Temperature-dependent aqueous solubilities of various organic compounds are of fundamental importance in many branches of environmental science. In a number of situations, the gas/dissolved solute of interest has characteristic spectroscopic absorption that is distinct from that of the solvent. For such cases, we report facile nondestructive rapid measurement of the temperature-dependent Henry's law constant (K(H)) in a static sealed spectrometric cell. Combined with a special cell design, multiwavelength measurement permits a large range of K(H) to be spanned. It is possible to derive the K(H) values from the absorbance measured in the gas phase only, the liquid phase only (preferred), and both phases. Underlying principles are developed, and all three approaches are illustrated for a solute like acetone in water. A thermostatic spectrophotometer cell compartment, widely used and available, facilitates rapid temperature changes and allows rapid temperature-dependent equilibrium measurements. Applicability is shown for both acetone and methyl isobutyl ketone. Very little sample is required for the measurement; the K(H) for 4-hydroxynonenal, a marker for oxidative stress, is measured to be 56.9 ± 2.6 M/atm (n = 3) at 37.4 °C with 1 mg of the material available.

Coupled oxygen-carbon dioxide modelling to partition potential external contribution to stream carbon dioxide concentrations.

NASA Astrophysics Data System (ADS)

Butman, D. E.; Holtgrieve, G. W.

2017-12-01

Recent modelling studies in large catchments have estimated that in excess of 74% of the dissolved carbon dioxide found in first and second order streams originate from allochthonous sources. Stable isotopes of carbon-13 in carbon dioxide have been used to identify ground water seeps in stream systems, where decreases in δ13CO2 occur along gaining stream reaches, suggesting that carbon dioxide in ground water is more depleted than what is found in surface water due to fractionation of CO2 during emissions across the air water interface. Although isotopes represent a chemical tracer in stream systems for potential groundwater contribution, the temporal resolution of discrete samples make partitioning allochthonous versus autochthonous sources of CO2 difficult on hydrologically relevant time scales. Here we show results of field deployments of high frequent dissolved CO2, O2, PAR, Temperature and pH from the Thornton Creek Watershed, the largest urban watershed in Seattle, WA. We present an exploration into using high resolution time series of dissolved oxygen and carbon dioxide in a dual gas approach to separate the contribution of in stream respiration from external sources. We extend upon previous efforts to model stream metabolism across diel cycles by incorporating simultaneous direct measurements of dissolved oxygen, PCO2, and pH within an inverse modeling framework and Bayesian parameter estimation. With an initial assumption of a stoichiometric ratio of 1:1 for O2 and CO2 for autochthonous driven metabolism, we investigate positive or negative departures from this ratio as an indicator of external CO2 to the stream (terrestrial or atmospheric) and factors contributing to this flux.

Effects of Bubble-Mediated Processes on Nitrous Oxide Dynamics in Denitrifying Bioreactors

NASA Astrophysics Data System (ADS)

McGuire, P. M.; Falk, L. M.; Reid, M. C.

2017-12-01

To mitigate groundwater and surface water impacts of reactive nitrogen (N), agricultural and stormwater management practices can employ denitrifying bioreactors (DNBs) as low-cost solutions for enhancing N removal. Due to the variable nature of hydrologic events, DNBs experience dynamic flows which can impact physical and biological processes within the reactors and affect performance. A particular concern is incomplete denitrification, which can release the potent greenhouse gas nitrous oxide (N2O) to the atmosphere. This study aims to provide insight into the effects of varying hydrologic conditions upon the operation of DNBs by disentangling abiotic and biotic controls on denitrification and N2O dynamics within a laboratory-scale bioreactor. We hypothesize that under transient hydrologic flows, rising water levels lead to air entrapment and bubble formation within the DNB porous media. Mass transfer of oxygen (O2) between trapped gas and liquid phases creates aerobic microenvironments that can inhibit N2O reductase (NosZ) enzymes and lead to N2O accumulation. These bubbles also retard N2O transport and make N2O unavailable for biological reduction, further enhancing atmospheric fluxes when water levels fall. The laboratory-scale DNB permits measurements of longitudinal and vertical profiles of dissolved constituents as well as trace gas concentrations in the reactor headspace. We describe a set of experiments quantifying denitrification pathway biokinetics under steady-state and transient hydrologic conditions and evaluate the role of bubble-mediated processes in enhancing N2O accumulation and fluxes. We use sulfur hexafluoride and helium as dissolved gas tracers to examine the impact of bubble entrapment upon retarded gas transport and enhanced trace gas fluxes. A planar optode sensor within the bioreactor provides near-continuous 2-D profiles of dissolved O2 within the bioreactor and allows for identification of aerobic microenvironments. We use qPCR to examine the relative abundance of the denitrifying genes nitrate reductase and NosZ within the bioreactor and explore gradients in denitrification biomarkers coinciding with denitrification intermediate profiles. Insights gained from this study will advance understanding of gas dynamics within environmental porous media.

Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations

NASA Astrophysics Data System (ADS)

Miller, Clint M.; Dickens, Gerald R.; Jakobsson, Martin; Johansson, Carina; Koshurnikov, Andrey; O'Regan, Matt; Muschitiello, Francesco; Stranne, Christian; Mörth, Carl-Magnus

2017-06-01

Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH4) in sediments as gas hydrate and free gas. Although release of this CH4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO42-), alkalinity, and the δ13C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143° E longitude. In the upper 8 m of these cores, downward SO42- flux never exceeds 6.2 mol m-2 kyr-1, the upward alkalinity flux never exceeds 6.8 mol m-2 kyr-1, and δ13C composition of DIC (δ13C-DIC) only moderately decreases with depth (-3.6 ‰ m-1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H2S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO42- and alkalinity were 13.9 and 11.3 mol m-2 kyr-1, respectively, the δ13C-DIC gradient was 5.6 ‰ m-1, and Mn2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH4, including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption.