Science.gov

Sample records for natural anaerobic groundwaters

  1. Anaerobic biotransformation of trichlorofluoroethene in groundwater microcosms

    SciTech Connect

    Vancheeswaran, S.; Semprini, L. . Dept. of Civil, Construction, and Environmental Engineering); Hyman, M.R. . Dept. of Microbiology)

    1999-06-15

    The biological reduction of trichlorofluoroethene (TCFE) was investigated in anaerobic groundwater microcosms. TCFE was reductively dehalogenated by microorganisms to produce three dichlorofluoroethene isomers, with cis-1,2-dichlorofluoroethene (c-DCFE) being the main isomer formed. Further sequential biological transformation of these compounds to mono-chlorofluoroethene isomers was incomplete and occurred at much slower rates. The rates of TCFE reduction were compared to the rates of reduction of two common chlorinated solvents, perchloroethene (PCE) and trichloroethene (TCE), when present at similar concentrations. Aqueous concentrations ranged from 7.0 to 14.0 mg/L for TCFE and from 7.5 to 15.0 mg/L for PCE and TCE. Similar rates of PCE and TCE transformation relative to TCFE were observed in single-compound tests (PCE, TCE, and TCFE in separate microcosms) and when the contaminants were present together as mixtures in the microcosms. The close similarities between the time course and kinetics of TCFE degradation and the degradation of both PCE and TCE, when present at comparable initial concentrations, suggest that TCFE could potentially be used as a benign reactive tracer to measure in-situ rates of PCE and TCE transformation in contaminated environments.

  2. Natural attenuation of xenobiotic compounds: Anaerobic field injection experiment

    SciTech Connect

    Ruegge, K.; Bjerg, P.L.; Mosbaek, H.; Christensen, T.H.

    1995-12-31

    Currently, a continuous field injection experiment is being performed in the anaerobic part of a pollution plume downgradient of the Grindsted Landfill in Denmark. This natural gradient experiment includes an injection of 18 different xenobiotic compounds with bromide as a tracer. The injection is taking place under methanogenic/sulfate-reducing conditions and the compounds will, as they migrate with the groundwater, pass through a zone where the redox conditions have been determined as iron-reducing.

  3. Carbon limitation of denitrification rates in an anaerobic groundwater system

    USGS Publications Warehouse

    Bradley, P.M.; Fernandez, M., Jr.; Chapelle, F.H.

    1992-01-01

    Rates of potential denitrification were determined for anaerobic aquifer sediments collected at a site where groundwater NO3 concentrations ranged from 0.7 ??M to 8.6 mM. A significant relation (p = 0.046) was observed between denitrification rates and the in situ concentration of NO3, but NO3 concentration only accounted for approximately 34% (r2) of the variation in activity. The highly significant relation (p < 0.001; r2 = 0.80) between potential denitrification and sediment total organic content and the enhanced activity of sediments amended with glucose indicated that denitrification rates in this aquifer system were carbon limited. No significant relation was observed between denitrification and the in situ groundwater pH, but short-term variations in pH influenced both the magnitude and the end products of denitrification. ?? 1992 American Chemical Society.

  4. Highly organic natural media as permeable reactive barriers: TCE partitioning and anaerobic degradation profile in eucalyptus mulch and compost.

    PubMed

    Öztürk, Zuhal; Tansel, Berrin; Katsenovich, Yelena; Sukop, Michael; Laha, Shonali

    2012-10-01

    Batch and column experiments were conducted with eucalyptus mulch and commercial compost to evaluate suitability of highly organic natural media to support anaerobic decomposition of trichloroethylene (TCE) in groundwater. Experimental data for TCE and its dechlorination byproducts were analyzed with Hydrus-1D model to estimate the partitioning and kinetic parameters for the sequential dechlorination reactions during TCE decomposition. The highly organic natural media allowed development of a bioactive zone capable of decomposing TCE under anaerobic conditions. The first order TCE biodecomposition reaction rates were 0.23 and 1.2d(-1) in eucalyptus mulch and compost media, respectively. The retardation factors in the eucalyptus mulch and compost columns for TCE were 35 and 301, respectively. The results showed that natural organic soil amendments can effectively support the anaerobic bioactive zone for remediation of TCE contaminated groundwater. The natural organic media are effective environmentally sustainable materials for use in permeable reactive barriers. PMID:22795070

  5. Degradation of natural and synthetic polyesters under anaerobic conditions.

    PubMed

    Abou-Zeid, D M; Müller, R J; Deckwer, W D

    2001-03-30

    Often, degradability under anaerobic conditions is desirable for plastics claimed to be biodegradable, e.g. in anaerobic biowaste treatment plants, landfills and in natural anaerobic sediments. The biodegradation of the natural polyesters poly(beta-hydroxybutyrate) (PHB), poly(beta-hydroxybutyrate-co-11.6%-beta-hydroxyvalerate) (PHBV) and the synthetic polyester poly(epsilon-caprolactone) (PCL) was studied in two anaerobic sludges and individual polyester degrading anaerobic strains were isolated, characterized and used for degradation experiments under controlled laboratory conditions. Incubation of PHB and PHBV films in two anaerobic sludges exhibited significant degradation in a time scale of 6-10 weeks monitored by weight loss and biogas formation. In contrast to aerobic conditions, PHB was degraded anaerobically more rapidly than the copolyester PHBV, when tested with either mixed cultures or a single strained isolate. PCL tends to degrade slower than the natural polyesters PHB and PHBV. Four PHB and PCL degrading isolates were taxonomically identified and are obviously new species belonging to the genus Clostridium group I. The depolymerizing enzyme systems of PHB and PCL degrading isolates are supposed to be different. Using one isolated strain in an optimized laboratory degradation test with PHB powder, the degradation time was drastically reduced compared to the degradation in sludges (2 days vs. 6-10 weeks). PMID:11245900

  6. Biogas production using anaerobic groundwater containing a subterranean microbial community associated with the accretionary prism

    PubMed Central

    Baito, Kyohei; Imai, Satomi; Matsushita, Makoto; Otani, Miku; Sato, Yu; Kimura, Hiroyuki

    2015-01-01

    In a deep aquifer associated with an accretionary prism, significant methane (CH4) is produced by a subterranean microbial community. Here, we developed bioreactors for producing CH4 and hydrogen (H2) using anaerobic groundwater collected from the deep aquifer. To generate CH4, the anaerobic groundwater amended with organic substrates was incubated in the bioreactor. At first, H2 was detected and accumulated in the gas phase of the bioreactor. After the H2 decreased, rapid CH4 production was observed. Phylogenetic analysis targeting 16S rRNA genes revealed that the H2-producing fermentative bacterium and hydrogenotrophic methanogen were predominant in the reactor. The results suggested that syntrophic biodegradation of organic substrates by the H2-producing fermentative bacterium and the hydrogenotrophic methanogen contributed to the CH4 production. For H2 production, the anaerobic groundwater, amended with organic substrates and an inhibitor of methanogens (2-bromoethanesulfonate), was incubated in a bioreactor. After incubation for 24 h, H2 was detected from the gas phase of the bioreactor and accumulated. Bacterial 16S rRNA gene analysis suggested the dominance of the H2-producing fermentative bacterium in the reactor. Our study demonstrated a simple and rapid CH4 and H2 production utilizing anaerobic groundwater containing an active subterranean microbial community. PMID:25267392

  7. Biogas production using anaerobic groundwater containing a subterranean microbial community associated with the accretionary prism.

    PubMed

    Baito, Kyohei; Imai, Satomi; Matsushita, Makoto; Otani, Miku; Sato, Yu; Kimura, Hiroyuki

    2015-09-01

    In a deep aquifer associated with an accretionary prism, significant methane (CH₄) is produced by a subterranean microbial community. Here, we developed bioreactors for producing CH₄ and hydrogen (H₂) using anaerobic groundwater collected from the deep aquifer. To generate CH₄, the anaerobic groundwater amended with organic substrates was incubated in the bioreactor. At first, H₂ was detected and accumulated in the gas phase of the bioreactor. After the H₂ decreased, rapid CH₄ production was observed. Phylogenetic analysis targeting 16S rRNA genes revealed that the H₂ -producing fermentative bacterium and hydrogenotrophic methanogen were predominant in the reactor. The results suggested that syntrophic biodegradation of organic substrates by the H₂ -producing fermentative bacterium and the hydrogenotrophic methanogen contributed to the CH₄ production. For H₂ production, the anaerobic groundwater, amended with organic substrates and an inhibitor of methanogens (2-bromoethanesulfonate), was incubated in a bioreactor. After incubation for 24 h, H₂ was detected from the gas phase of the bioreactor and accumulated. Bacterial 16S rRNA gene analysis suggested the dominance of the H₂ -producing fermentative bacterium in the reactor. Our study demonstrated a simple and rapid CH4 and H2 production utilizing anaerobic groundwater containing an active subterranean microbial community. PMID:25267392

  8. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    PubMed

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated. PMID:26577215

  9. Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: Groundwater biogeochemistry

    USGS Publications Warehouse

    Witt, M.E.; Klecka, G.M.; Lutz, E.J.; Ei, T.A.; Grosso, N.R.; Chapelle, F.H.

    2002-01-01

    Monitored natural attenuation (MNA) has recently emerged as a viable groundwater remediation technology in the United States. Area 6 at Dover Air Force Base (Dover, DE) was chosen as a test site to examine the potential for MNA of tetrachloroethene (PCE) and trichloroethene (TCE) in groundwater and aquifer sediments. A "lines of evidence" approach was used to document the occurrence of natural attenuation. Chlorinated hydrocarbon and biogeochemical data were used to develop a site-specific conceptual model where both anaerobic and aerobic biological processes are responsible for the destruction of PCE, TCE, and daughter metabolites. An examination of groundwater biogeochemical data showed a region of depleted dissolved oxygen with elevated dissolved methane and hydrogen concentrations. Reductive dechlorination likely dominated in the anaerobic portion of the aquifer where PCE and TCE levels were observed to decrease with a simultaneous increase in cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), ethene, and dissolved chloride. Near the anaerobic/aerobic interface, concentrations of cis-DCE and VC decreased to below detection limits, presumably due to aerobic biotransformation processes. Therefore, the contaminant and daughter product plumes present at the site appear to have been naturally attenuated by a combination of active anaerobic and aerobic biotransformation processes. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: groundwater biogeochemistry.

    PubMed

    Witt, Michael E; Klecka, Gary M; Lutz, Edward J; Ei, Tom A; Grosso, Nancy R; Chapelle, Francis H

    2002-07-01

    Monitored natural attenuation (MNA) has recently emerged as a viable groundwater remediation technology in the United States. Area 6 at Dover Air Force Base (Dover, DE) was chosen as a test site to examine the potential for MNA of tetrachloroethene (PCE) and trichloroethene (TCE) in groundwater and aquifer sediments. A "lines of evidence" approach was used to document the occurrence of natural attenuation. Chlorinated hydrocarbon and biogeochemical data were used to develop a site-specific conceptual model where both anaerobic and aerobic biological processes are responsible for the destruction of PCE, TCE, and daughter metabolites. An examination of groundwater biogeochemical data showed a region of depleted dissolved oxygen with elevated dissolved methane and hydrogen concentrations. Reductive dechlorination likely dominated in the anaerobic portion of the aquifer where PCE and TCE levels were observed to decrease with a simultaneous increase in cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), ethene, and dissolved chloride. Near the anaerobic/ aerobic interface, concentrations of cis-DCE and VC decreased to below detection limits, presumably due to aerobic biotransformation processes. Therefore, the contaminant and daughter product plumes present at the site appear to have been naturally atteuated by a combination of active anaerobic and aerobic biotransformation processes. PMID:12143993

  11. NATURAL ATTENUATION OF EXPLOSIVES IN GROUNDWATER

    EPA Science Inventory

    Monitored natural attenuation (MNA) is a remedial alternative for explosives contaminated groundwater at sites where a decline in contaminant mass can be demonstrated to occur at a rate sufficient to ensure the protection of potential receptors. MNA is not a no action alternative...

  12. Natural attenuation of perchlorate in denitrified groundwater.

    PubMed

    Robertson, William D; Roy, James W; Brown, Susan J; Van Stempvoort, Dale R; Bickerton, Greg

    2014-01-01

    Monitoring of a well-defined septic system groundwater plume and groundwater discharging to two urban streams located in southern Ontario, Canada, provided evidence of natural attenuation of background low level (ng/L) perchlorate (ClO4⁻) under denitrifying conditions in the field. The septic system site at Long Point contains ClO4⁻ from a mix of waste water, atmospheric deposition, and periodic use of fireworks, while the nitrate plume indicates active denitrification. Plume nitrate (NO3⁻ -N) concentrations of up to 103 mg/L declined with depth and downgradient of the tile bed due to denitrification and anammox activity, and the plume was almost completely denitrified beyond 35 m from the tile bed. The ClO4⁻ natural attenuation occurs at the site only when NO3⁻ -N concentrations are <0.3 mg/L, after which ClO4⁻ concentrations decline abruptly from 187 ± 202 to 11 ± 15 ng/L. A similar pattern between NO3⁻ -N and ClO4⁻ was found in groundwater discharging to the two urban streams. These findings suggest that natural attenuation (i.e., biodegradation) of ClO4⁻ may be commonplace in denitrified aquifers with appropriate electron donors present, and thus, should be considered as a remediation option for ClO4⁻ contaminated groundwater. PMID:23448242

  13. Anaerobic oxidation of methane by sulfate in hypersaline groundwater of the Dead Sea aquifer

    PubMed Central

    Avrahamov, N; Antler, G; Yechieli, Y; Gavrieli, I; Joye, S B; Saxton, M; Turchyn, A V; Sivan, O

    2014-01-01

    Geochemical and microbial evidence points to anaerobic oxidation of methane (AOM) likely coupled with bacterial sulfate reduction in the hypersaline groundwater of the Dead Sea (DS) alluvial aquifer. Groundwater was sampled from nine boreholes drilled along the Arugot alluvial fan next to the DS. The groundwater samples were highly saline (up to 6300 mm chlorine), anoxic, and contained methane. A mass balance calculation demonstrates that the very low δ13CDIC in this groundwater is due to anaerobic methane oxidation. Sulfate depletion coincident with isotope enrichment of sulfur and oxygen isotopes in the sulfate suggests that sulfate reduction is associated with this AOM. DNA extraction and 16S amplicon sequencing were used to explore the microbial community present and were found to be microbial composition indicative of bacterial sulfate reducers associated with anaerobic methanotrophic archaea (ANME) driving AOM. The net sulfate reduction seems to be primarily controlled by the salinity and the available methane and is substantially lower as salinity increases (2.5 mm sulfate removal at 3000 mm chlorine but only 0.5 mm sulfate removal at 6300 mm chlorine). Low overall sulfur isotope fractionation observed (34ε = 17 ± 3.5‰) hints at high rates of sulfate reduction, as has been previously suggested for sulfate reduction coupled with methane oxidation. The new results demonstrate the presence of sulfate-driven AOM in terrestrial hypersaline systems and expand our understanding of how microbial life is sustained under the challenging conditions of an extremely hypersaline environment. PMID:25039851

  14. Assessment of microbial natural attenuation in groundwater polluted with gasworks residues.

    PubMed

    Schulze, S; Tiehm, A

    2004-01-01

    Intrinsic biodegradation, representing the key process in Natural Attenuation, was examined at a tar-oil polluted disposal site. Methods to assess microbial natural attenuation of BTEX and PAH included analysis of groundwater hydrochemistry, pollutant profiles, composition of the microflora, and microcosm studies. In the polluted groundwater downgradient the disposal site, oxygen and nitrate were only available adjacent to the groundwater table and at the plume fringes. In the anaerobic core of the plume, a sequence of predominating redox zones (methanogenic, sulphate-reducing, Fe(III)-reducing) was observed. Changing pollutant profiles in the plume indicated active biodegradation processes, e.g. biodegradation of toluene and naphthalene in the anaerobic zones. High numbers of microorganisms capable of growing under anaerobic conditions and of aerobic pollutant degrading organisms confirmed the impact of biodegradation at this site. In microcosm studies, the autochthonous microflora utilised toluene, ethylbenzene, and naphthalene under sulfate- and Fe(III)-reducing conditions. Additionally, benzene and phenanthrene were degraded in the presence of Fe(III). Under aerobic conditions, all BTEX and PAH were rapidly degraded. The microcosm studies in particular were suitable to examine the role of specific electron acceptors, and represented an important component of the multiple line of evidence concept to assess natural attenuation. PMID:15497868

  15. Natural attenuation of chlorinated volatile organic compounds in a freshwater tidal wetland: Field evidence of anaerobic biodegradation

    USGS Publications Warehouse

    Lorah, M.M.; Olsen, L.D.

    1999-01-01

    Field evidence collected along two groundwater flow paths shows that anaerobic biodegradation naturally attenuates a plume of chlorinated volatile organic compounds as it discharges from an aerobic sand aquifer through wetland sediments. A decrease in concentrations of two parent contaminants, trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (PCA), and a concomitant increase in concentrations of anaerobic daughter products occurs along upward flow paths through the Wetland sediments. The daughter products 1,2-dichloroethylene, vinyl chloride, 1,1,2-trichloroethane, and 1,2-dichloroethane are produced from hydrogenolysis of TCE and from PCA degradation through hydrogenolysis and dichloroelimination (reductive dechlorination) pathways. Total concentrations of TCE, PCA, and their degradation products, however, decrease to below detection levels within 0.15-0.30 m of land surface. The enhanced reductive dechlorination of TCE and PCA in the wetland sediments is associated with the naturally higher concentrations of dissolved organic carbon and the lower redox state of the groundwater compared to the aquifer. This field study indicates that wetlands and similar organic-rich environments at groundwater/surface-water interfaces may be important in intercepting groundwater contaminated with chlorinated organics and in naturally reducing concentrations and toxicity before sensitive surface-water receptors are reached.

  16. Anaerobic biodegradation and hydrogeochemical controls on natural attenuation of trichloroethene in an inland forested wetland

    USGS Publications Warehouse

    Lorah, M.M.; Dyer, L.J.; Burris, D.R.

    2007-01-01

    Anaerobic biodegradation was conducted in a forested wetland where a plume of trichloroethylene discharges from a sand aquifer through organic-rich wetland and stream-bottom sediments. The rapid response of the wetland hydrology to precipitation events altered groundwater flow and geochemistry during wet conditions in the spring compared to the drier conditions in the summer and fall. During dry conditions, partial reductive dechlorination of trichloroethylene to cis-1,2-dichloroethylene occurred in methanogenic wetland porewater. Influx of oxygenated recharge during wet conditions led to a change from methanogenic to iron-reducing conditions and a lack of 1,2-dichloroethylene production in the wet spring conditions. During these wet conditions, dilution was the primary attenuation mechanism evident for trichloroethylene in the wetland porewater. Trichloroethylene degradation was insignificant in anaerobic microcosms constructed with the shallow wetland sediment. Natural attenuation of chlorinated solvents by anaerobic biodegradation may not be efficient at all wetland sites, despite organic-rich characteristics of the sediment.

  17. Anaerobic treatment of natural tannin extracts in UASB reactors.

    PubMed

    López-Fluza, J; Omil, F; Méndez, R

    2003-01-01

    Tannin extracts are substances commonly used in leather production processes. Since most of the steps of tannery manufacturing processes are carried out in aqueous environments, the presence of these compounds in the wastewaters is important. The aim of this work is to study the feasibility of the anaerobic degradation of three natural tannin extracts in three Upflow Anaerobic Sludge Blanket (UASB) reactors, which were fed with increasing concentrations of two condensed (quebracho and wattle) and one hydrolysable tannin extract (chestnut). Concentrations of applied extracts were 100, 200, 400, 800 and 1,000 mg/l, and 5 g/l of glucose was used as cosubstrate. Reactors were operated during 210 days and their performance was evaluated from the values of total and soluble COD, total and intermediate alkalinity, volatile fatty acids, pH and UV absorption at 280 nm. COD removal efficiencies higher than 85% were achieved in all cases. However, tannin extract removal efficiencies (based on UV-280 nm absorption measurements) were significantly lower, around 20% for condensed extracts and 60% for the hydrolysable one, when the reactors operated with the highest tannin extract concentration. The operation of the reactors was stable, commonly with alkalinity ratios below 0.30. Mass balances carried out indicate that most of the COD removal efficiencies are due to the removal of the readily biodegradable organic matter (glucose), whereas the tannin extracts are hardly anaerobically biodegradable, especially condensed extracts (wattle and quebracho). PMID:14640213

  18. Vinegar-amended anaerobic biosand filter for the removal of arsenic and nitrate from groundwater.

    PubMed

    Snyder, Kathryn V; Webster, Tara M; Upadhyaya, Giridhar; Hayes, Kim F; Raskin, Lutgarde

    2016-04-15

    The performance of a vinegar-amended anaerobic biosand filter was evaluated for future application as point-of-use water treatment in rural areas for the removal of arsenic and nitrate from groundwater containing common ions. Due to the importance of sulfate and iron in arsenic removal and their variable concentrations in groundwater, influent sulfate and iron concentrations were varied. Complete removal of influent nitrate (50 mg/L) and over 50% removal of influent arsenic (200 μg/L) occurred. Of all conditions tested, the lowest median effluent arsenic concentration was 88 μg/L. Iron removal occurred completely when 4 mg/L was added, and sulfate concentrations were lowered to a median concentration <2 mg/L from influent concentrations of 22 and 50 mg/L. Despite iron and sulfate removal and the establishment of reducing conditions, arsenic concentrations remained above the World Health Organization's arsenic drinking water standard. Further research is necessary to determine if anaerobic biosand filters can be improved to meet the arsenic drinking water standard and to evaluate practical implementation challenges. PMID:26871878

  19. Nature's Helpers: Using Microorganisms to Remove Trichloroethene (TCE) from Groundwater

    NASA Astrophysics Data System (ADS)

    Delgado, A. G.; Krajmlanik-Brown, R.; Fajardo-Williams, D.; Halloum, I.

    2015-12-01

    Organic chlorinated solvents, such as perchloroethene (PCE) and trichloroethene (TCE), are toxic pollutants threatening ground water quality worldwide and present at many superfund sites. Bioremediation using microorganisms is a promising, green, efficient, and sustainable approach to remove PCE and TCE contamination from soil and groundwater. Under anaerobic conditions, specialized microorganisms (dechlorinators) can reduce these chlorinated ethenes to ethene, an innocuous product, and gain energy for growth by a process known as reductive dechlorination. Dechlorinators are most often present in the environment and in dechlorinating cultures alongside other microbes such as fermenters, methanogens, and acetogens. Fermenters, methanogens, and acetogens syntrophically provide essential nutrients and growth factors to dechlorinators, most specifically to the only members able to reduce TCE all the way to ethene: Dehalococcoides; unfortunately, they also compete with dechlorinators for electron donors. My laboratory devises reductive chlorination platforms to study competition and syntrophy among Dehalococcoides, and other microbes to optimize remediation reactions and transport in the subsurface. We look at competing processes present as part of the natural soil chemistry and microbiology and address these challenges through a combination of enrichment techniques, molecular microbial ecology (deep sequencing), water chemistry, and electron balances. We have applied knowledge gathered in my laboratory to: 1) enrich microbial dechlorinating cultures capable of some of the fastest rates of TCE to ethene dechlorination ever reported, and 2) successfully design and operate three different continuous dechlorinating reactor types. We attribute our successful reactor operations to our multidisciplinary approach which links microbiology and engineering. Our reactors produce robust dechlorinating cultures used for in-situ bioaugmentation of PCE and TCE at contaminated sites

  20. Molecular and Stable Isotope Investigation of Nitrite Respiring Bacterial Communities Capable of Anaerobic Ammonium Oxidation (ANAMMOX) and Denitrifying Anaerobic Methane Oxidation (DAMO) in Nitrogen Contaminated Groundwater

    NASA Astrophysics Data System (ADS)

    Song, B.; Hirsch, M.; Taylor, J.; Smith, R. L.; Repert, D.; Tobias, C. R.

    2010-12-01

    Anaerobic ammonium oxidation (ANAMMOX) and denitrifying anaerobic methane oxidation (DAMO) are two recently discovered N2 production pathways in the microbial nitrogen cycle. ANAMMOX has been relatively well investigated in various aquatic ecosystems, while DAMO has been examined only in freshwater wetlands. However, neither ANAMMOX nor DAMO have been studied in groundwater ecosystems as microbial N removal processes where they could compliment or compete with denitrification to remediate N contaminated aquifers. Thus, we conducted molecular and stable isotope analyses to detect and measure ANAMMOX and DAMO in a nitrogen contaminated aquifer on Cape Cod, Massachusetts. The study site has a plume of nitrogen contaminated groundwater as a result of continuous discharge of treated wastewater over 60 years. Groundwater was collected from multiport sampling devices installed at two sites, near the waste-water disposal location (A) and more than 3 km down gradient (B) along the contamination plume. Biomass was collected from water samples for DNA extraction and 15N tracer incubation experiments. PCR with specific 16S rRNA gene primers detected the presence of ANAMMOX and DAMO bacteria at both sites. Phylogenetic analysis of 16S rRNA genes revealed that the ANAMMOX community at site A was most associated with Kuenenia spp. while site B had a community more closely related to Brocadia spp. The DAMO communities at the two sites were quite different based on 16S rRNA gene analysis. The communities at site B are closely associated with Candidatus “Methylomirabilis oxyfera”, which is the first enriched DAMO culture. Most of the 16S rRNA sequences detected in site A were related to those found in other DAMO enrichment cultures established from a eutrophic ditch sediment. In order to determine active members of ANAMMOX communities, the transcriptional expression of hydrazine oxidase (hzo) and hydrazine hydrolase (hh) genes was examined at both sites. In addition, 15N tracer

  1. Groundwater surface water interaction study using natural isotopes tracer

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  2. Microbial reduction and precipitation of vanadium (V) in groundwater by immobilized mixed anaerobic culture.

    PubMed

    Zhang, Baogang; Hao, Liting; Tian, Caixing; Yuan, Songhu; Feng, Chuanping; Ni, Jinren; Borthwick, Alistair G L

    2015-09-01

    Vanadium is an important contaminant impacted by natural and industrial activities. Vanadium (V) reduction efficiency as high as 87.0% was achieved by employing immobilized mixed anaerobic sludge as inoculated seed within 12h operation, while V(IV) was the main reduction product which precipitated instantly. Increasing initial V(V) concentration resulted in the decrease of V(V) removal efficiency, while this index increased first and then decreased with the increase of initial COD concentration, pH and conductivity. High-throughput 16S rRNA gene pyrosequencing analysis indicated the decreased microbial diversity. V(V) reduction was realized through dissimilatory reduction process by significantly enhanced Lactococcus and Enterobacter with oxidation of lactic and acetic acids from fermentative microorganisms such as the enriched Paludibacter and the newly appeared Acetobacterium, Oscillibacter. This study is helpful to detect new functional species for V(V) reduction and constitutes a step ahead in developing in situ bioremediations of vanadium contamination. PMID:26067477

  3. Design Of Bioremediation Systems For Groundwater (Aerobic and Anaerobic Plus Representative Case Studies)

    EPA Science Inventory

    The attached presentation discusses the fundamentals of bioremediation in the subsurface. The basics of aerobic, cometabolic, and anaerobic bioremediation are presented. Case studies from the Delaware Sand & Gravel Superfund Site, Dover Cometabolic Research Project and the SABR...

  4. Natural discharge : a key to sustainable utilization of fossil groundwater.

    SciTech Connect

    Sultan, M.; Yan, E.; Sturchio, N.; Wagdy, A.; Abdel Gelil, K.; Becker, R.; Manocha, N.; Milewski, A.; Environmental Science Division; Western Michigan Univ.; Univ. of Illinois at Chicago; Cairo Univ.; Ministry of Water Resources and Irrigagion

    2007-01-01

    Rising demands for fresh water supplies in arid lands are leading to excessive exploitation and unsustainable mining of non-renewable fossil groundwater. Using the Nubian Aquifer of Saharan Africa as a test site, we demonstrate an integrated approach to identify areas of discharge that could have gone undetected, and to model extraction that is sustained by natural discharge. Using isotopic and geochemical analyses along with field and remote sensing data we show that discharge of the Nubian Aquifer is occurring on a larger scale, primarily through deep-seated fault systems, and that ascending groundwater discharges into relatively thick alluvial aquifers proximal to the fault complex that defines the River Nile and the Gulf of Suez. We develop a hydrologic model to assess the discharge and to constrain sustainable extraction in the Asyuti area along the River Nile and to demonstrate a replicable model for similar reservoirs. A two-dimensional groundwater flow model was constructed and calibrated against head data from 19 wells. Results point to a significant contribution to the Asyuti groundwater system from rising Nubian groundwater (3.19 x 10{sup 7} m{sup 3}/yr: 75% of incoming flow) and a modest contribution (1.08 x 10{sup 7} m{sup 3}/yr: 25% of incoming flow) from surface runoff. Approximately 2.5 x 10{sup 7} m{sup 3}/yr of groundwater could be used in a sustainable manner in Asyuti. Assuming geologic settings and discharge rates similar to those at Asyuti, we estimate that 70 x 10{sup 7} m{sup 3}/yr of groundwater may be available for sustainable development in similar settings around the River Nile and the Gulf of Suez.

  5. Assessment of natural arsenic in groundwater in Cordoba Province, Argentina.

    PubMed

    Francisca, Franco M; Carro Perez, Magalí E

    2009-12-01

    Groundwater in the central part of Argentina contains arsenic concentrations that, in most cases, exceed the value suggested by international regulations. In this region, Quaternary loessical sediments with a very high volcanic glass fraction lixiviate arsenic and fluoride after weathering. The objectives of this study are to analyze the spatial distribution of arsenic in different hydrogeological regions, to define the naturally expected concentration in an aquifer by means of hydrogeochemistry studies, and to identify emergent health evidences related to cancer mortality in the study area. The correlation between arsenic and fluoride concentrations in groundwater is analyzed at each county in the Cordoba Province. Two dimensionless geoindicators are proposed to identify risk zones and to rapidly visualize the groundwater quality related to the presence of arsenic and fluoride. A surface-mapping system is used to identify the spatial variability of concentrations and for suggesting geoindicators. The results show that the Chaco-Pampean plain hydrogeologic region is the most affected area, with arsenic and fluoride concentrations in groundwater being generally higher than the values suggested by the World Health Organization (WHO) for drinking water. Mortality related to kidney, lung, liver, and skin cancer in this area could be associated to the ingestion of arsenic-contaminated water. Generated maps provide a base for the assessment of the risk associated to the natural occurrence of arsenic and fluoride in the region. PMID:19165608

  6. Anaerobic Oxalate Degradation: Widespread Natural Occurrence in Aquatic Sediments

    PubMed Central

    Smith, Richard L.; Oremland, Ronald S.

    1983-01-01

    Significant concentrations of oxalate (dissolved plus particulate) were present in sediments taken from a diversity of aquatic environments, ranging from 0.1 to 0.7 mmol/liter of sediment. These included pelagic and littoral sediments from two freshwater lakes (Searsville Lake, Calif., and Lake Tahoe, Calif.), a hypersaline, meromictic, alkaline lake (Big Soda Lake, Nev.), and a South San Francisco Bay mud flat and salt marsh. The oxalate concentration of several plant species which are potential detrital inputs to these aquatic sediments ranged from 0.1 to 5.0% (wt/wt). In experiments with litter bags, the oxalate content of Myriophyllum sp. samples buried in freshwater littoral sediments decreased to 7% of the original value in 175 days. This suggests that plant detritus is a potential source of the oxalate within these sediments. [14C]oxalic acid was anaerobically degraded to 14CO2 in all sediment types tested, with higher rates evident in littoral sediments than in the pelagic sediments of the lakes studied. The turnover time of the added [14C]oxalate was less than 1 day in Searsville Lake littoral sediments. The total sediment oxalate concentration did not vary significantly between littoral and pelagic sediments and therefore did not appear to be controlling the rate of oxalate degradation. However, depth profiles of [14C]oxalate mineralization and dissolved oxalate concentration were closely correlated in freshwater littoral sediments; both were greatest in the surface sediments (0 to 5 cm) and decreased with depth. The dissolved oxalate concentration (9.1 μmol/liter of sediment) was only 3% of the total extractable oxalate (277 μmol/liter of sediment) at the sediment surface. These results suggest that anaerobic oxalate degradation is a widespread phenomenon in aquatic sediments and may be limited by the dissolved oxalate concentration within these sediments. PMID:16346332

  7. Estimating natural background groundwater chemistry, Questa molybdenum mine, New Mexico

    USGS Publications Warehouse

    Verplanck, Phillip L.; Nordstrom, D Kirk; Plumlee, Geoffrey S.; Walker, Bruce M.

    2010-01-01

    This 2 1/2 day field trip will present an overview of a U.S. Geological Survey (USGS) project whose objective was to estimate pre-mining groundwater chemistry at the Questa molybdenum mine, New Mexico. Because of intense debate among stakeholders regarding pre-mining groundwater chemistry standards, the New Mexico Environment Department and Chevron Mining Inc. (formerly Molycorp) agreed that the USGS should determine pre-mining groundwater quality at the site. In 2001, the USGS began a 5-year, multidisciplinary investigation to estimate pre-mining groundwater chemistry utilizing a detailed assessment of a proximal natural analog site and applied an interdisciplinary approach to infer pre-mining conditions. The trip will include a surface tour of the Questa mine and key locations in the erosion scar areas and along the Red River. The trip will provide participants with a detailed understanding of geochemical processes that influence pre-mining environmental baselines in mineralized areas and estimation techniques for determining pre-mining baseline conditions.

  8. [Recovery of facultatives and anaerobes from frozen specimens with a polymicrobial nature].

    PubMed

    Kawamura, Chizuko; Nakamura, Toshihiko; Kaimori, Mitsuomi; Watanabe, Kunitomo

    2003-01-01

    Microbiological examination of frozen specimens is sometimes carried out in clinical microbiology and the result is used as an aid of diagnosis and/or treatment of polymicrobial infections. The study was carried out to reevaluate the merit of freezing specimens in clinical microbiology. A total of 10 specimens with a polymicrobial nature were included in this study. Before and after freezing specimens, we isolated facultative and anaerobic bacteria using a set of primary isolation media, consisting of three aerobic agar plates (MacConkey agar, blood agar and chocolate agar) and four pre-reduced anaerobic agar plates (HK Blood agar, HK blood agar with paromomycin (PM) and vancomycin (VM), phenyl ethyl-alcohol (PEA) agar and Bacteroides bile esculin (BBE) agar). All the procedures were done in a properly controlled anaerobic chamber. The number of isolates before and after freezing was 79 and 70, respectively. Among the strains isolated before freezing, 33 strains were recovered on the same kin of media artery freezing, without a remarkable decrease in the quantity. But 26 strains were not recovered and 2 strains were recovered with a remarkable decrease. Among 26 strains, 15 strains could be successfully backed up on the different kind of media. In conclusion, an anaerobic technique with an anaerobic chamber and a set of isolatin plates including blood agar, chocolate agar, HK blood agar, PEA blood agar, HK blood agar with PM and VM enable us to estimate the bacteriology before freezing from frozen specimens. PMID:14984303

  9. Natural attenuation of N-nitrosodimethylamine in soil and groundwater

    SciTech Connect

    Gunnison, D.; Gates, M.; Evans, W.

    1995-12-31

    N-nitrosodimethylamine (NMDA) has been detected in groundwater and in the influent as well as effluent from the Rocky Mountain Arsenal (RMA) North Boundary Treatment System (NTBS). Since nitrosamines possess carcinogenic, teratogenic, mutagenic, and hepatotoxic properties at low concentrations, their presence in groundwater is disconcerting. However, even though NDMA has been found in the water samples collected from observation wells, it has not been detected in any of the off-post wells. Therefore, the abundance of NDMA-degrading populations and the rate and extent of mineralization of NDMA by the microorganisms in the granulated activated carbon (GAC) absorber units, recharge trenches, and saturated aquifer soils was investigated in this study. A significant activity of NDMA-degrading microbes was detected in these samples, which suggests that microbial degradation may be a major cause of NDMA attenuation in natural systems. The results of microbial enumerations and biodegradation studies will be presented in this presentation.

  10. EFFECT OF ETHANOL ON THE NATURAL ANAEROBIC BIODEGRADATION OF BENZENE

    EPA Science Inventory

    Ethanol is commonly used as a fuel oxygenate. A concern has been raised that the presence of ethanol from a spill of gasoline may inhibit the natural biodegradation of fuel hydrocarbons, including benzene. Ethanol is miscible in water, and ethanol is readily metabolized by micr...

  11. SITE BULLETIN, ATTENUATED ANAEROBIC DECHLORINATION OF GROUNDWATER USING HRC MACTEC - HARDING ESE

    EPA Science Inventory

    A SITE demonstration of the Harding ESE permeable reactive barrier wall (PRBW) was conducted on the contaminated groundwater from the Fisherville Mill site in Grafton, MA beginning June 2000 to July 2003. Installation of the PRBW was accomplished by injecting HRC into a series of...

  12. Deployment Plan for Bioremediation and Natural Attenuation for In Situ Restoration of Chloroethene-Contaminated Groundwater

    SciTech Connect

    Peterson, L.N.; Starr, R.C.; Sorenson, K.S.; Smith, R.W.; Phelps, T.J.

    1999-03-01

    This deployment plan describes a project funded by the Accelerated Site Technology Deployment Program of the U.S. Department of Energy (DOE). The objective is to facilitate deployment of enhanced in situ bioremediation (ISB) an monitored natural attenuation (MNA) or chloroethene-contaminated groundwater to DOE sites. Enhanced ISB accelerates dechlorination of chloroethenes under anaerobic conditions by providing nutrients to the microbial community. Natural attenuation does not require nutrient addition. Enhanced ISB in the upgradient portion of a contaminant plume couples with MNA in the downgradient portion is being implemented at Test Area North (TAN) at the Idaho National Engineering and Environmental Laboratory. Selected DOE sites will be screened to assess their suitability for enhanced ISB/MNA. Tasks include: (1) characterization of the TAN microbial community and correlation of community characteristics with chloroethene degradation ability, (2) installation of wells to facilitate evaluation of MNA at TAN, (3) monitoring to better delineate MNA at TAN, and (4) screening of selected other DOE sites for suitability of ISB/MNA, and limited supplemental characterization. Data evaluation will provide a sound technical basis for decision makers to consider use of enhanced ISB and MNA, alone or together, as remedial technologies for these sites.

  13. Mobilization Of Polonium-210 In Naturally-Contaminated Groundwater, Churchill County, Nevada

    NASA Astrophysics Data System (ADS)

    Seiler, R. L.; Stillings, L. L.; Cutler, N.

    2009-12-01

    Polonium-210 activities in groundwater rarely exceed about 40 mBq/L because it strongly binds to sediments. The recent discovery of natural 210Po at levels ranging from below 1 to 6,300±280 mBq/L in 62 drinking-water wells in Lahontan Valley, Churchill County, Nevada, led to a geochemical investigation of the processes responsible for its mobilization from the aquifer sediments. The source of the 210Po is radioactive decay of uranium in sediments transported into the valley by erosion of granitic rocks in the Sierra Nevada during the Pleistocene. There is little spatial or depth variability in 210Pb activity in study-area sediments (average 35 Bq/kg) and detailed analysis at a contaminated well indicates mobilization of <0.5 percent of the 210Po in the sediments would account for all of the 210Po in the well water. Elevated 210Po activities (>200 mBq/L) are associated with anoxic water (DO <0.1 mg/L) with high pH (commonly >9.0). Investigations in the 1980s by William Burnett and colleagues of naturally-contaminated wells in Florida showed that 210Po was mobilized by sulfate-reducing bacteria and remained in solution as long as sulfides did not accumulate above certain levels. Similarly, δ34SSO4 values in Lahontan Valley indicate that significant sulfate reduction has occurred in wells containing >200 mBq/L of 210Po, but sulfide is not accumulating and its concentrations are low (<0.03 mg/L) in 25 of 28 of those wells. In our working hypothesis, mobilization of 210Po in Lahontan Valley is linked to reduction of Mn oxides by sulfide in an anaerobic sulfur cycle (Figure 1). Such a sulfur cycle is consistent with the high pH, less than predicted δ18OSO4 values, low sulfide concentrations, and presence of elemental sulfur in the water. Results from the Nevada and Florida investigations suggest that 210Po contamination may be more widespread than previously recognized, occurring in groundwater near uranium-mine operations and other uranium containing sediments when

  14. Groundwater.

    ERIC Educational Resources Information Center

    Braids, Olin C.; Gillies, Nola P.

    1978-01-01

    Presents a literature review of groundwater quality covering publications of 1977. This review includes: (1) sources of groundwater contamination; and (2) management of groundwater. A list of 59 references is also presented. (HM)

  15. Natural attenuation potential of phenylarsenicals in anoxic groundwaters.

    PubMed

    Hempel, Michael; Daus, Birgit; Vogt, Carsten; Weiss, Holger

    2009-09-15

    The extensive production of chemical warfare agents in the 20th century has led to serious contamination of soil and groundwater with phenyl arsenicals at former ammunition depots or warfare agent production sites worldwide. Most phenyl arsenicals are highly toxic for humans. The microbial degradation of phenylarsonic acid (PAA) and diphenylarsinic acid (DPAA) was investigated in microcosms made of anoxic groundwater/sediment mixtures taken from different depths of an anoxic, phenyl arsenical contaminated aquifer in Central Germany. DPAA was not transformed within 91 days incubation time in any of the microcosms. The removal of PAA can be described by a first order kinetics without a lag-phase (rate: 0.037 d(-1)). In sterilized microcosms, PAA concentrations always remained stable, demonstrating that PAA transformation was a biologically mediated process. PAA transformation occurred under sulfate-reducing conditions due to sulfate consumption and production of sulfide. The addition of lactate (1 mM), a typical substrate of sulfate-reducing bacteria, increased the transformation rate of PAA significantly up to 0.134 d(-1). The content of total arsenic was considerably reduced (> 75%). Intermediates of PAA transformation were detected by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Experiments with a pure strain and sterile controls of Desulfovibrio gigas spiked with PAA showed that the elimination process is linked to the presence of sulfide formed through bacterial activity. Phenyl arsenicals were likely immobilized in the sedimentthrough sulfur substitution and a subsequent sulfur bond under the prevailing sulfate reducing condition. The results of this study indicate that PAA can undergo microbiologically mediated transformation in anoxic aquifers, leading to reduced concentrations in groundwater, which indicate a (enhancend) natural attenuation potential. PMID:19806732

  16. Characterization of the anaerobic denitrification bacterium Acinetobacter sp. SZ28 and its application for groundwater treatment.

    PubMed

    Su, Jun feng; Zheng, Sheng Chen; Huang, Ting lin; Ma, Fang; Shao, Si Cheng; Yang, Shao Fei; Zhang, Li na

    2015-09-01

    Acinetobacter sp. SZ28 exhibited efficient autotrophic denitrification ability using Mn(2+) as an electron donor. Sequence amplification identified the presence of the nirS gene. Meteorological chromatography analysis showed that N2 was produced as an end product. Response surface methodology experiments showed that the maximum removal of nitrate occurred under the following conditions: Mn(2+) concentration of 143.56 mg/L, C/N ratio of 6.82, initial pH of 5.17, and temperature of 34.26 °C, where the initial Mn(2+) concentration produced the largest effect. In the groundwater experiment, nitrate levels decreased from 1.63 mg/L to 0 mg/L. Three-dimensional fluorescence analysis showed a decrease in the peak intensity of the original humus. Humus and the small-molecule amino acid tryptophan were detected. These results demonstrated that strain SZ28 is a suitable candidate for the simultaneous removal of nitrogen and Mn(2+) in groundwater treatment. PMID:26094190

  17. Natural water purification and water management by artificial groundwater recharge

    PubMed Central

    Balke, Klaus-Dieter; Zhu, Yan

    2008-01-01

    Worldwide, several regions suffer from water scarcity and contamination. The infiltration and subsurface storage of rain and river water can reduce water stress. Artificial groundwater recharge, possibly combined with bank filtration, plant purification and/or the use of subsurface dams and artificial aquifers, is especially advantageous in areas where layers of gravel and sand exist below the earth’s surface. Artificial infiltration of surface water into the uppermost aquifer has qualitative and quantitative advantages. The contamination of infiltrated river water will be reduced by natural attenuation. Clay minerals, iron hydroxide and humic matter as well as microorganisms located in the subsurface have high decontamination capacities. By this, a final water treatment, if necessary, becomes much easier and cheaper. The quantitative effect concerns the seasonally changing river discharge that influences the possibility of water extraction for drinking water purposes. Such changes can be equalised by seasonally adapted infiltration/extraction of water in/out of the aquifer according to the river discharge and the water need. This method enables a continuous water supply over the whole year. Generally, artificially recharged groundwater is better protected against pollution than surface water, and the delimitation of water protection zones makes it even more save. PMID:18357624

  18. Modeling of natural organic matter transport processes in groundwater.

    PubMed Central

    Yeh, T C; Mas-Pla, J; McCarthy, J F; Williams, T M

    1995-01-01

    A forced-gradient tracer test was conducted at the Georgetown site to study the transport of natural organic matter (NOM) in groundwater. In particular, the goal of this experiment was to investigate the interactions between NOM and the aquifer matrix. A detailed three-dimensional characterization of the hydrologic conductivity heterogeneity of the site was obtained using slug tests. The transport of a conservative tracer (chloride) was successfully reproduced using these conductivity data. Despite the good simulation of the flow field, NOM breakthrough curves could not be reproduced using a two-site sorption model with spatially constant parameters. Preliminary results suggest that different mechanisms for the adsorption/desorption processes, as well as their spatial variability, may significantly affect the transport and fate of NOM. PMID:7621798

  19. A case study of the natural attenuation of gas condensate hydrocarbons in soil and groundwater.

    PubMed

    Barker, G W; Raterman, K T; Fisher, J B; Corgan, J M; Trent, G L; Brown, D R; Kemp, N; Sublette, K L

    1996-01-01

    Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, Fe(III) reduction, and sulfate reduction. PMID:8669918

  20. Natural Arsenic Pollution of Groundwater in Mining Zones of Mexico

    NASA Astrophysics Data System (ADS)

    Armienta, M. A.; Rodriguez, R.; Villasennor, G.; Romero, F.; Talavera, O.; Ceniceros, N.; Aguayo, A.; Cruz, O.

    2007-05-01

    Arsenic concentrations exceeding drinking-water standards have been measured in groundwater of various areas of Mexico. This is a relevant public health problem since groundwater supplies most drinking water of the country. Although a natural source has been proposed as the cause of water contamination at most sites, the specific processes releasing As have only been identified in a few aquifers. The geological characteristics of Mexico including volcanic, geothermal, and highly mineralized zones constitute favorable environments for As occurrence. Furthermore, As-abundance in bedrock has lead Mexico to be one of the major world As-producers. As-bearing minerals like arsenopyrite, scorodite, mimetite, adamite, tennantite and nickeline can be found in several zones. Besides, arsenic may be a minor component of Fe, Ag, Cu, Pb, Zn, and Au ores. While thousands of people have been chronically exposed to As, arsenic-related health effects have been documented only for residents at some Mexican locations, like Comarca Lagunera, Zimapan, and Acambaro. Water-rock interactions may release As to water in mining areas, but ore extraction and processing produce surface wastes that can also release As to groundwater. Investigations developed in two historical mining zones revealed different As contents in groundwater. At Zimapan, a semi-arid area about 250 km NE of Mexico City, abundant arsenopyrite and hydrogeological conditions produced high As concentrations in deep wells exploited for drinking water supply. Oxidation and dissolution of As-bearing minerals mainly arsenopyrite, scorodite and tennantite released As to the fractured deep limestone aquifer. In addition, mining operations polluted shallow wells. In contrast, low levels of As were detected in wells near mine tailings in the warm sub-humid zone of Taxco, Guerrero. To explain those differences, the mineralogy and the geochemical processes occurring in tailings at both areas were studied. Results showed that besides

  1. Seasonal Variations of Biogeochemical Characteristics in Predominantly Anaerobic Groundwater From a Riverine Alluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Koh, D.; Ha, K.; Kim, K.; Ko, K.

    2007-12-01

    Hydrogeochemical parameters were investigated for groundwater from six multi-level wells (up to 30 m deep) in a riverine alluvial aquifer with intense agricultural activities of rice, barley and vegetable cultivation during two sampling campaigns in rainy summer (July) and dry spring (March) season to identify seasonal variation in biogeochemical processes in the aquifer. The alluvial aquifer is located in flooldplains of Mangyeong River, western part of South Korea near the city of Jeonju. pH, concentrations of Na, Cl, Ca, F have little difference between the two sampling periods. Electrical conductivity (EC) and concentrations of HCO3, Mg, SO4 slightly increased as a whole from rainy season to dry season. Dissolved concentrations of major ions in river water increased by more than three fold during the seasons. These feature indicates that the groundwater system is relatively stable and less affected by the river in hydrogeochemical aspects. Dissolve oxygen (DO) concentrations were less than 1 mg/L for most of the wells whereas two wells turned to aerobic conditions in dry season which can be attributed to removal of stagnant water in the paddy fields. NO3 concentrations decreased significantly in dry season at most well points near the paddy fields. This indicates that denitrification is dominant over nitrate supply by infiltrating water from the land surface which is likely to be significantly decreased after harvesting of rice during the dry season. However, NO3 increased in upper zones (<10 m) in two wells near the barley and vegetable fields, which suggest continued nitrate supply from the crop fields to the upper part of the aquifer during the season. Fe concentrations have relatively small variations in most of wells for two sampling periods. However, from rainy season to dry season, Fe concentrations significantly increased more than two fold in two wells whereas NO3 concentration decreased below detection limit from 2 to 8 mg/L. The increase of Fe

  2. Groundwater dynamics converted to a groundwater classification as a tool for nature development programs in the dunes

    NASA Astrophysics Data System (ADS)

    Martens, Kristine; Van Camp, Marc; Van Damme, Dirk; Walraevens, Kristine

    2013-08-01

    Within the European Union, Habitat Directives are developed with the aim of restoration and preservation of endangered species. The level of biodiversity in coastal dune systems is generally very high compared to other natural ecosystems, but suffers from deterioration. Groundwater extraction and urbanisation are the main reasons for the decrease in biodiversity. Many restoration actions are being carried out and are focusing on the restoration of groundwater level with the aim of re-establishing rare species. These actions have different degrees of success. The evaluation of the actions is mainly based on the appearance of red list species. The groundwater classes, developed in the Netherlands, are used for the evaluation of opportunities for vegetation, while the natural variability of the groundwater level and quality are under-estimated. Vegetation is used as a seepage indicator. The existing classification is not valid in the Belgian dunes, as the vegetation observed in the study area is not in correspondence with this classification. Therefore, a new classification is needed. The new classification is based on the variability of the groundwater level on a long term with integration of ecological factors. Based on the new classification, the importance of seasonal and inter-yearly fluctuations of the water table can be deduced. Inter-yearly fluctuations are more important in recharge areas while seasonal fluctuations are dominant in discharge areas. The new classification opens opportunities for relating vegetation and groundwater dynamics.

  3. Unraveling the heat island effect observed in urban groundwater bodies - Definition of a potential natural state

    NASA Astrophysics Data System (ADS)

    Epting, Jannis; Huggenberger, Peter

    2013-09-01

    A superposition of several thermal processes leads to an elevation of groundwater temperatures of up to 9 °C above the natural state in the city of Basel, Switzerland. The urban thermal groundwater regime is influenced by: (1) urbanization and annual heating periods; (2) thermal groundwater use; (3) seasonal trends; (4) river-groundwater interaction; and (5) climate change and consequences thereof. The combination of short- and long-term data analysis, including conventional and high-resolution multilevel groundwater temperature monitoring, as well as 3D numerical groundwater flow and heat-transport modeling allowed quantifying the thermal influences on the investigated urban groundwater body. Results facilitate to describe the “present state” of the urban thermal groundwater regime and to derive a “potential natural state” of the investigated groundwater body. The study originated from a request of the executive council to provide a basis for cost estimates of infrastructure adaptation measures necessary to mitigate the impact of climate change. It is shown that the principal trigger for the observed thermal development is not climate change but that local and regional anthropogenic factors are dominating. Although in urban areas, groundwater is increasingly used for cooling purposes; the geothermal potential, resulting from elevated groundwater temperatures, is generally not exploited. The presented approach provides a basis for the setup of combined and thermally balanced heating and cooling systems.

  4. Dissolution rate of alpha-doped UO2 in natural groundwater

    NASA Astrophysics Data System (ADS)

    Ollila, Kaija; Myllykylä, Emmi; Tanhua-Tyrkkö, Merja; Lavonen, Tiina

    2013-11-01

    The objective of this work is to determine whether the presence of trace elements in natural groundwaters affects the dissolution rate of uranium dioxide in the presence of alpha radiation that causes radiolysis of water. The study is a part of the project Reducing Uncertainty in Performance Prediction (REDUPP) under the Seventh Framework Programme of the European Atomic Energy Community (EURATOM). The project aims to reduce uncertainties related to the extrapolation of the results of laboratory experiments to the conditions expected under geologic disposal. Thus far, synthetic groundwater has been normally used in the experiments. The synthetic groundwaters used do not contain all of the chemical elements that occur in natural groundwaters. Three natural groundwaters were chosen for the dissolution experiments with 0%, 5%, and 10% 233U-doped UO2 samples. These include a brackish groundwater, a saline groundwater and a low ionic strength groundwater. At the time of writing this paper, the dissolution experiments have been finished in the first groundwater, which was a moderately saline, brackish groundwater. The groundwater samples for the experiments were taken from a borehole in the Olkiluoto site in Finland. The measurements for dissolution rates were conducted under reducing conditions established using metallic iron in solution and an argon atmosphere in the glove box. The isotope dilution method was used to decrease uncertainties due to precipitation and sorption effects. The resulting dissolution rates in OL-KR6 natural groundwater were generally somewhat higher than the rates measured previously in synthetic groundwaters under similar redox conditions. No clear effect of alpha radiolysis could be seen for tests with lower SA/V, while those for higher SA/V indicated that the dissolution rate was higher for the 10% 233U-doped UO2, suggesting the effect of alpha radiolysis under these conditions.

  5. Influence of different natural zeolite concentrations on the anaerobic digestion of piggery waste.

    PubMed

    Milán, Z; Sánchez, E; Weiland, P; Borja, R; Martín, A; Ilangovan, K

    2001-10-01

    The effect of different natural zeolite concentrations on the anaerobic digestion of piggery waste was studied. Natural zeolite doses in the range 0.2-10 g/l of wastewater were used in batch experiments, which were carried out at temperatures between 27 degrees C and 30 degrees C. Total chemical oxygen demand (COD), total and volatile solids, ammonia and organic nitrogen, pH, total volatile fatty acids (TVFA), alkalinity (Alk) and accumulative methane production were determined during 30 days of digestion. The anaerobic digestion process was favored by the addition of natural zeolite at doses between 2 and 4 g/l and increasingly inhibited at doses beyond 6 g/l. A first-order kinetic model of COD removal was used to determine the apparent kinetic constants of the process. The kinetic constant values increased with the zeolite amount up to a concentration of 4 g/l. The values of the maximum accumulative methane production (Gm) increased until zeolite concentrations of 2-4 g/l. The addition of zeolite reduced the values of the TVFA/ Alk ratio while increasing the pH values, and these facts could contribute to the process failure at zeolite doses of 10 g/l. PMID:11554599

  6. Denitrification of groundwater using a sulfur-oxidizing autotrophic denitrifying anaerobic fluidized-bed MBR: performance and bacterial community structure.

    PubMed

    Zhang, Lili; Zhang, Chao; Hu, Chengzhi; Liu, Huijuan; Qu, Jiuhui

    2015-03-01

    This paper investigates a novel sulfur-oxidizing autotrophic denitrifying anaerobic fluidized bed membrane bioreactor (AnFB-MBR) that has the potential to overcome the limitations of conventional sulfur-oxidizing autotrophic denitrification systems. The AnFB-MBR produced consistent high-quality product water when fed by a synthetic groundwater with NO3 (-)-N ranging 25-80 mg/L and operated at hydraulic retention times of 0.5-5.0 h. A nitrate removal rate of up to 4.0 g NO3 (-)-N/Lreactord was attained by the bioreactor, which exceeded any reported removal capacity. The flux of AnFB-MBR was maintained in the range of 1.5-15 L m(-2) h(-1). Successful membrane cleaning was practiced with cleaning cycles of 35-81 days, which had no obvious effect on the AnFB-MBR performance. The (15) N-tracer analyses elucidated that nitrogen was converted into (15) N2-N and (15) N-biomass accounting for 88.1-93.1 % and 6.4-11.6 % of the total nitrogen produced, respectively. Only 0.3-0.5 % of removed nitrogen was in form of (15)N2O-N in sulfur-oxidizing autotrophic denitrification process, reducing potential risks of a significant amount of N2O emissions. The sulfur-oxidizing autotrophic denitrifying bacterial consortium was composed mainly of bacteria from Proteobacteria, Chlorobi, and Chloroflexi phyla, with genera Thiobacillus, Sulfurimonas, and Ignavibacteriales dominating the consortium. The pyrosequencing assays also suggested that the stable microbial communities corresponded to the elevated performance of the AnFB-MBR. Overall, this research described relatively high nitrate removal, acceptable flux, indicating future potential for the technology in practice. PMID:25343972

  7. Use of activated carbon and natural zeolite as support materials, in an anaerobic fluidised bed reactor, for vinasse treatment.

    PubMed

    Fernández, N; Fdz-Polanco, F; Montalvo, S J; Toledano, D

    2001-01-01

    In Cuba, the alcohol distillation process from cane sugar molasses, produces a final waste (vinasse), with an enormous polluting potential and a high sulfate content. Applying the anaerobic technology, most of the biodegradable organic matter can turn into biogas, rich in methane but with concentrations of sulfide above 1%. The present work develops two experiences with anaerobic fluidized bed reactors (AFBR) using both Cuban raw material, activated carbon and natural zeolite, as support media, with the purpose of obtaining high organic matter removal rates and keeping sulfide and ammonium concentrations in the permissible ranges. The reactors were operated during 120 days, achieving an organic loading rate of 10 kg COD/m3 day, with COD removal above 70%, and a methane production of 2 L/d. The activated carbon and natural zeolite used support materials in anaerobic fluidized bed reactors, and showed good results of distillery waste removal. PMID:11575071

  8. Site Characterization To Support Use Of Monitored Natural Attentuation For Remediation Of Inorganic Contaminants In Groundwater

    EPA Science Inventory

    Technical recommendations have recently been published by the U.S. Environmental Protection Agency to address site characterization needed to support selection of Monitored Natural Attenuation (MNA) for cleanup of inorganic contaminant plumes in groundwater. Immobilization onto ...

  9. Assessment of natural attenuation of aromatic hydrocarbons in groundwater near a former manufactured-gas plant, South Carolina, USA

    USGS Publications Warehouse

    Landmeyer, J.E.; Chapelle, F.H.; Petkewich, M.D.; Bradley, P.M.

    1998-01-01

    Shallow, anaerobic groundwater near a former manufactured-gas plant (MGP) in Charleston, South Carolina, USA, contains mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs, respectively). Between 1994 and 1997, a combination of field, laboratory, and numerical-flow and transport-model investigations were made to assess natural attenuation processes affecting MAH and PAH distributions. This assessment included determination of adsorption coefficients (K(ad)) and first-order biodegradation rate constants (K(bio)) using aquifer material from the MGP site and adjacent properties. Naphthalene adsorption (K(ad) = 1.35 x 10-7 m3/mg) to aquifer sediments was higher than toluene adsorption (K(ad) = 9.34 x 10-10 m3/mg), suggesting preferential toluene transport relative to naphthalene. However, toluene and benzene distributions measured in January 1994 were smaller than the naphthalene distribution. This scenario can be explained, in part, by the differences between biodegradation rates of the compounds. Aerobic first-order rate constants of 14C-toluene, 14C-benzene, and 14C-naphthalene degradation were similar (-0.84, -0.03, and 0.88 day-1, respectively), but anaerobic rate constants were higher for toluene and benzene (-0.002 and -0.00014 day-1, respectively) than for naphthalene (-0.000046 day-1). Both areal and cross-sectional numerical simulations were used to test the hypothesis suggested by these rate differences that MAH compounds will be contained relative to PAHs. Predictive simulations indicated that the distributions of toluene and benzene reach steady-state conditions before groundwater flow lines discharge to an adjacent surface-water body, but do discharge low concentrations of naphthalene. Numerical predictions were 'audited' by measuring concentrations of naphthalene, toluene, and benzene at the site in early 1997. Measured naphthalene and toluene concentrations were substantially reduced and the areal extent of contamination smaller than was both

  10. Distribution and environmental significance of nitrite-dependent anaerobic methane-oxidising bacteria in natural ecosystems.

    PubMed

    Shen, Li-dong; Wu, Hong-sheng; Gao, Zhi-qiu

    2015-01-01

    Nitrite-dependent anaerobic methane oxidation (N-DAMO) is a recently discovered process that is performed by "Candidatus Methylomirabilis oxyfera" (M. oxyfera). This process constitutes a unique association between the two major global elements essential to life, carbon and nitrogen, and may act as an important and overlooked sink of the greenhouse gas methane. In recent years, more and more studies have reported the distribution of M. oxyfera-like bacteria and the occurrence of N-DAMO process in different natural ecosystems, including freshwater lakes, rivers, wetlands and marine ecosystems. Previous studies have estimated that a total of 2%-6% of current worldwide methane flux in wetlands could be consumed via the N-DAMO process. These findings indicate that N-DAMO is indeed a previously overlooked methane sink in natural ecosystems. Given the worldwide increase in anthropogenic nitrogen pollution, the N-DAMO process as a methane sink in reducing global warming could become more important in the future. The present mini-review summarises the current knowledge of the ecological distribution of M. oxyfera-like bacteria and the potential importance of the N-DAMO process in reducing methane emissions in various natural ecosystems. The potential influence of environmental factors on the N-DAMO process is also discussed. PMID:25398284

  11. Anaerobic oxidation of methane associated with sulfate reduction in a natural freshwater gas source.

    PubMed

    Timmers, Peer Ha; Suarez-Zuluaga, Diego A; van Rossem, Minke; Diender, Martijn; Stams, Alfons Jm; Plugge, Caroline M

    2016-06-01

    The occurrence of anaerobic oxidation of methane (AOM) and trace methane oxidation (TMO) was investigated in a freshwater natural gas source. Sediment samples were taken and analyzed for potential electron acceptors coupled to AOM. Long-term incubations with (13)C-labeled CH4 ((13)CH4) and different electron acceptors showed that both AOM and TMO occurred. In most conditions, (13)C-labeled CO2 ((13)CO2) simultaneously increased with methane formation, which is typical for TMO. In the presence of nitrate, neither methane formation nor methane oxidation occurred. Net AOM was measured only with sulfate as electron acceptor. Here, sulfide production occurred simultaneously with (13)CO2 production and no methanogenesis occurred, excluding TMO as a possible source for (13)CO2 production from (13)CH4. Archaeal 16S rRNA gene analysis showed the highest presence of ANME-2a/b (ANaerobic MEthane oxidizing archaea) and AAA (AOM Associated Archaea) sequences in the incubations with methane and sulfate as compared with only methane addition. Higher abundance of ANME-2a/b in incubations with methane and sulfate as compared with only sulfate addition was shown by qPCR analysis. Bacterial 16S rRNA gene analysis showed the presence of sulfate-reducing bacteria belonging to SEEP-SRB1. This is the first report that explicitly shows that AOM is associated with sulfate reduction in an enrichment culture of ANME-2a/b and AAA methanotrophs and SEEP-SRB1 sulfate reducers from a low-saline environment. PMID:26636551

  12. Hydrogeological interpretation of natural radionuclide contents in Austrian groundwaters

    NASA Astrophysics Data System (ADS)

    Schubert, Gerhard; Berka, Rudolf; Hörhan, Thomas; Katzlberger, Christian; Landstetter, Claudia; Philippitsch, Rudolf

    2010-05-01

    The Austrian Agency for Health and Food Safety (AGES) stores comprehensive data sets of radionuclide contents in Austrian groundwater. There are several analyses concerning Rn-222, Ra-226, gross alpha and gross beta as well as selected analyses of Ra-228, Pb-210, Po-210, Uranium and U-234/U-238. In a current project financed by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management, AGES and the Geological Survey of Austria (GBA) are evaluating these data sets with regard to the geological backgrounds. Several similar studies based on groundwater monitoring have been made in the USA (for instance by Focazio, M.J., Szabo, Z., Kraemer, T.F., Mullin, A.H., Barringer, T.H., De Paul, V.T. (2001): Occurrence of selected radionuclides in groundwater used for drinking water in the United States: a reconnaissance survey, 1998. U.S. Geological Survey Water-Resources Investigations Report 00-4273). The geological background for the radionuclide contents of groundwater will be derived from geological maps in combination with existing Thorium and Uranium analyses of the country rocks and stream-sediments and from airborne radiometric maps. Airborne radiometric data could contribute to identify potential radionuclide hot spot areas as only airborne radiometric mapping could provide countrywide Thorium and Uranium data coverage in high resolution. The project will also focus on the habit of the sampled wells and springs and the hydrological situation during the sampling as these factors can have an important influence on the Radon content of the sampled groundwater (Schubert, G., Alletsgruber, I., Finger, F., Gasser, V., Hobiger, G. and Lettner, H. (2010): Radon im Grundwasser des Mühlviertels (Oberösterreich) Grundwasser. - Springer (in print). Based on the project results an overview map (1:500,000) concerning the radionuclide potential should be produced. The first version should be available in February 2011.

  13. Hydrochemistry of the natural low pH groundwater in the coastal aquifers near Beihai, China

    NASA Astrophysics Data System (ADS)

    Zhou, Xun; Shen, Ye; Zhang, Hua; Song, Chao; Li, Jingwei; Liu, Yan

    2015-06-01

    Natural weak acidic groundwater occurs in the unconfined and confined aquifers consisting of Quaternary and Neogene unconsolidated sediments near Beihai in southern Guangxi, China. Under natural conditions the groundwater has low TDS (less than 200 mg L-1) and low concentrations of trace elements (less than 100 µg L-1) with a deceasing tend in contents of the Lanthanides (rare earth elements, less than 1 µg L-1) towards higher atomic number. The groundwater ranges in pH from 3.33 to 7.0 with an average value of 5.12 (even lower than that of local rainwater, 5.88). pH values in the groundwater are a bit higher in rainy seasons than those in dry seasons and do not show significant increasing or decreasing trend with time. The average pH value in groundwater in the confined aquifers is even a bit lower than that in the unconfined aquifer. Comprehensive analyses of the groundwater environment suggest that H+ in the groundwater may be derived from dissociation of H2CO3, release of the absorbed H3O+ in clay layers and the acidity of rainwater. The H2CO3 in the groundwater may be formed by dissolution of CO2 (g). Minerals in the unconsolidated sediment are predominated by quartz with small amount of clay minerals. The sediments undergoing a long-term weathering contain low levels of soluble constitutes. Lack of alkaline substances in the groundwater system is also helpful in the accumulation of acidity of the groundwater.

  14. Natural Gas Occurrence in Groundwater near Oil and Gas Drilling Sites Environmental Concerns in Northeast Pennsylvania

    NASA Astrophysics Data System (ADS)

    Arjmand, S.; Abad, J. D.; Liang, X.

    2012-12-01

    Hydraulic fracturing and horizontal drilling techniques have been extensively used to extract unconventional natural gas in the northeast of the United States. Over the past few years, the presence of contaminants in shallow groundwater near drilling sites has created higher awareness of drinking water quality. One key question has been recently raised about the origin and pathways of the contaminants, especially natural gas found in groundwater in neighboring areas of gas drilling sites in northeast Pennsylvania. Methane (CH4), which is the main component of natural gas, is not currently classified as a health hazard when dissolved in drinking water. Yet, it is a threat for explosion and fire hazards. In the Bradford, Susquehanna, Tioga, and Wyoming counties located in northeast Pennsylvania, dissolved methane concentration was measured to be 19.2 mg/l. Maximum concentration was recorded up to 64 mg/l when a warning level of concentration of natural gas in groundwater is only 10 mg/l. Recent studies have been investigating the origin of natural gas found in water wells in these counties based on the isotopic composition of methane, ethane and dissolved inorganic carbon. While Breen et al. (2007) and Osborn et al. (2010 and 2011) claim that the isotopic analysis of methane confirms the thermogenic origin of methane in groundwater in Susquehanna and Wyoming counties, Molofsky et al. (2011) claim that the natural gas origin in the groundwater is not related to fracking activities in the Marcellus Shale but to a geologic origin instead. To better understand the origin of dissolved methane, an integral computer model will be implemented. The model will analyze the potential migration of natural gas to shallow groundwater by using available data. Potential scenarios will include outgassing from wells casing and preferential flow through deep fractures. Currently, the lack of a proper model prevents the prediction and explanation of several of the existing questions

  15. Dissolution and Mobilization of Uranium in a Reduced Sediment by Natural Humic Substances under Anaerobic Conditions

    SciTech Connect

    Gu, Baohua; Luo, Wensui

    2009-01-01

    Biological reduction and precipitation of uranium (U) has been proposed as a remedial option for immobilizing uranium at contaminated sites, but the long-term stability and mobility of uranium remain a concern because it is neither removed nor destroyed. In this study, the dissolution and mobilization of reduced and oxidized forms of uranium [U(IV) and U(VI)] by natural humic substances were investigated in batch and column flow systems using a bioreduced sediment containing both U(IV) and U(VI). The addition of humic substances significantly increased the dissolution of U(IV) under anaerobic conditions. Humic acid (HA) was found to be more effective than fulvic acid (FA) in dissolving U(IV) in either 1 mM KCl or KHCO3 background solution. However, more U(VI) was dissolved in 1 mM KHCO3 than in 1 mM KCl background electrolytes. The HA also was found to be more effective than FA in mobilizing uranium under reducing and column flow conditions, although an accumulative amount of eluted U(VI) and U(IV) was relatively low (<60 g) after leaching with ~97 pore volumes of the humic solution in 1 mM KHCO3. These observations suggest that natural humic substances could potentially influence the long-term stability of bioreduced U(IV) even under strong reducing environments.

  16. Groundwater ''fast paths'' in the Snake River plain aquifer: Radiogenic isotope ratios as natural groundwater tracers

    SciTech Connect

    Johnson, Thomas M.; Roback, Robert C.; McLing, Travis L.; Bullen, Thomas D.; DePaolo, Donald J.; Doughty, Christine; Hunt, Randall J.; Smith, Robert W.; Cecil, L. DeWayne; Murrell, Michael T.

    2000-09-01

    Preferential flow paths are expected in many groundwater systems and must be located because they can greatly affect contaminant transport. The fundamental characteristics of radiogenic isotope ratios in chemically evolving waters make them highly effective as preferential flow path indicators. These ratios tend to be more easily interpreted than solute-concentration data because their response to water-rock interaction is less complex. We demonstrate this approach with groundwater {sup 87}Sr/{sup 86}Sr ratios in the Snake River Plain aquifer within and near the Idaho National Engineering and Environmental Laboratory. These data reveal slow-flow zones as lower {sup 87}Sr/{sup 86}Sr areas created by prolonged interaction with the host basalts and a relatively fast flowing zone as a high {sup 87}Sr/{sup 86}Sr area.

  17. Bioremediation: A natural solution. [Decontamination of soils and groundwater

    SciTech Connect

    Hicks, B.N.; Caplan, J.A. )

    1993-01-15

    Bioremediation is an attractive remediation alternative because most full-scale bioremediation projects involve cost-effective contaminant treatment on-site. Recently, large scale bioremediation projects have included cleanups of ocean tanker spills, land-based chemical spills, and leaking chemical and petroleum storage tanks. Contaminated matrices have included beaches, soils, groundwater, surface waters (i.e., pits, ponds, lagoons), process waste streams and grease traps. Bioremediation is especially cost-effective when both soil and groundwater matrices are impacted because one remediation treatment system can be design to treat both media simultaneously in place. The primary advantages of in situ bioremediation include: on-site destruction of contaminants; accelerated cleanup time; minimal disruption to operations; lower remediation costs; and reduction of future liability.

  18. EFFECT OF NONCOLIFORMS ON COLIFORM DETECTION IN POTABLE GROUNDWATER: IMPROVED RECOVERY WITH AN ANAEROBIC MEMBRANE FILTER TECHNIQUE

    EPA Science Inventory

    A total of 529 well and distribution potable water samples were analyzed for total coliforms by the most-probable-number and membrane filter (MF) techniques. Standard plate count bacteria and MF noncoliform bacteria were also enumerated. This anaerobic modification of the standar...

  19. Natural organic matter as electron acceptor: experimental evidence for its important role in anaerobic respiration

    NASA Astrophysics Data System (ADS)

    Lau, Maximilian Peter; Sander, Michael; Gelbrecht, Jörg; Hupfer, Michael

    2014-05-01

    Microbial respiration is a key driver of element cycling in oxic and anoxic environments. Upon depletion of oxygen as terminal electron acceptor (TEA), a number of anaerobic bacteria can employ alternative TEA for intracellular energy generation. Redox active quinone moieties in dissolved organic matter (DOM) are well known electron acceptors for microbial respiration. However, it remains unclear whether quinones in adsorbed and particulate OM accept electrons in a same way. In our studies we aim to understand the importance of natural organic matter (NOM) as electron acceptors for microbial energy gain and its possible implications for methanogenesis. Using a novel electrochemical approach, mediated electrochemical reduction and -oxidation, we can directly quantify reduced hydroquinone and oxidized quionone moieties in dissolved and particulate NOM samples. In a mesocosm experiment, we rewetted sediment and peat soil and followed electron transfer to the inorganic and organic electron acceptors over time. We found that inorganic and organic electron acceptor pools were depleted over the same timescales. More importantly, we showed that organic, NOM-associated electron accepting moieties represent as much as 21 40% of total TEA inventories. These findings support earlier studies that propose that the reduction of quinone moieties in particulate organic matter competitively suppresses methanogenesis in wetland soils. Our results indicate that electron transfer to organic, particulate TEA in inundated ecosystems has to be accounted for when establishing carbon budgets in and projecting greenhouse gas emissions from these systems.

  20. Nature and chlorine reactivity of organic constituents from reclaimed water in groundwater, Los Angeles County, California

    USGS Publications Warehouse

    Leenheer, J.A.; Rostad, C.E.; Barber, L.B.; Schroeder, R.A.; Anders, R.; Davisson, M.L.

    2001-01-01

    The nature and chlorine reactivity of organic constituents in reclaimed water (tertiary-treated municipal wastewater) before, during, and after recharge into groundwater at the Montebello Forebay in Los Angeles County, CA, was the focus of this study. Dissolved organic matter (DOM) in reclaimed water from this site is primarily a mixture of aromatic sulfonates from anionic surfactant degradation, N-acetyl amino sugars and proteins from bacterial activity, and natural fulvic acid, whereas DOM from native groundwaters in the aquifer to which reclaimed water was recharged consists of natural fulvic acids. The hydrophilic neutral N-acetyl amino sugars that constitute 40% of the DOM in reclaimed water are removed during the first 3 m of vertical infiltration in the recharge basin. Groundwater age dating with 3H and 3He isotopes, and determinations of organic and inorganic C isotopes, enabled clear differentiation of recent recharged water from older native groundwater. Phenol structures in natural fulvic acids in DOM isolated from groundwater produced significant trihalomethanes (THM) and total organic halogen (TOX) yields upon chlorination, and these structures also were responsible for the enhanced SUVA and specific fluorescence characteristics relative to DOM in reclaimed water. Aromatic sulfonates and fulvic acids in reclaimed water DOM produced minimal THM and TOX yields.

  1. Identification of manganese as a toxicant in a groundwater treatment system: Addressing naturally occurring toxicants

    SciTech Connect

    Goodfellow, W. Jr.; Sohn, V.; Richey, M.; Yost, J.

    1995-12-31

    Effluent from a groundwater remediation system at a bulk oil storage and distribution terminal has been chronically toxic to Ceriodaphnia dubia. The remediation system was designed in response to a hydrocarbon plume in the area of the terminal. The remediation system consists of a series of groundwater recovery wells and groundwater intercept trench systems with groundwater treatment and phased-separated hydrocarbon recovery systems. The groundwater treatment and petroleum recovery systems consist of oil/water separators, product recovery tanks, air strippers, filters, and carbon adsorption units. The characteristics of this effluent are low total suspended solids, total dissolved solids, and hardness concentrations as well as meeting stringent NPDES permit requirements for lead, copper, zinc, mercury, total petroleum hydrocarbons, and BTEX. Additional priority pollutant evaluations revealed no compounds of concern. Performance of a Toxicity identification Evaluation (TIE) indicated that manganese was the principle toxicant in the effluent. Manganese is a naturally occurring constituent in this groundwater source and is not added to the treatment system. This paper will present the results of the TIE with a discussion of treatability/control options for manganese control at this facility. Recommendations for addressing naturally occurring toxicants that are not a result of the facility`s operations will also be presented.

  2. Groundwater ages and mixing in the Piceance Basin natural gas province, Colorado

    USGS Publications Warehouse

    McMahon, Peter B.; Thomas, Judith C.; Hunt, Andrew G.

    2013-01-01

    Reliably identifying the effects of energy development on groundwater quality can be difficult because baseline assessments of water quality completed before the onset of energy development are rare and because interactions between hydrocarbon reservoirs and aquifers can be complex, involving both natural and human processes. Groundwater age and mixing data can strengthen interpretations of monitoring data from those areas by providing better understanding of the groundwater flow systems. Chemical, isotopic, and age tracers were used to characterize groundwater ages and mixing with deeper saline water in three areas of the Piceance Basin natural gas province. The data revealed a complex array of groundwater ages (50,000 years) and mixing patterns in the basin that helped explain concentrations and sources of methane in groundwater. Age and mixing data also can strengthen the design of monitoring programs by providing information on time scales at which water quality changes in aquifers might be expected to occur. This information could be used to establish maximum allowable distances of monitoring wells from energy development activity and the appropriate duration of monitoring.

  3. Effects of natural attenuation processes on groundwater contamination caused by abandoned waste sites in Berlin

    NASA Astrophysics Data System (ADS)

    Kerndorff, Helmut; Kühn, Stephan; Minden, Thomas; Orlikowski, Dagmar; Struppe, Thomas

    2008-07-01

    The aim of this research project is to identify, characterize and quantify natural attenuation (NA) processes in groundwater affected by emissions of abandoned waste disposal sites in Berlin-Kladow/Gatow, Germany. It is part of the funding priority called KORA established by the Federal Ministry for Education and Research (BMBF) to explore the extent to which NA can be used for remedial purposes for varied forms of soil and groundwater contamination. Information on the emission behaviour of individual parameters is generated on the basis of hydrogeochemical comparison of 20 years old and new data. Using groundwater-modelling and CFC-analysis, information on the transport and retention of pollutants in groundwater is compiled. The microbial colonization of contaminated aquifers is characterized by molecular biological methods [polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE)] to differentiate between contaminated and not contaminated zones.

  4. Distribution and activity of anaerobic ammonium-oxidising bacteria in natural freshwater wetland soils.

    PubMed

    Shen, Li-dong; Wu, Hong-sheng; Gao, Zhi-qiu; Cheng, Hai-xiang; Li, Ji; Liu, Xu; Ren, Qian-qi

    2016-04-01

    Anaerobic ammonium oxidation (anammox) process plays a significant role in the marine nitrogen cycle. However, the quantitative importance of this process in nitrogen removal in wetland systems, particularly in natural freshwater wetlands, is still not determined. In the present study, we provided the evidence of the distribution and activity of anammox bacteria in a natural freshwater wetland, located in southeastern China, by using (15)N stable isotope measurements, quantitative PCR assays and 16S rRNA gene clone library analysis. The potential anammox rates measured in this wetland system ranged between 2.5 and 25.5 nmol N2 g(-1) soil day(-1), and up to 20% soil dinitrogen gas production could be attributed to the anammox process. Phylogenetic analysis of 16S rRNA genes showed that anammox bacteria related to Candidatus Brocadia, Candidatus Kuenenia, Candidatus Anammoxoglobus and two novel anammox clusters coexisted in the collected soil cores, with Candidatus Brocadia and Candidatus Kuenenia being the dominant anammox genera. Quantitative PCR of hydrazine synthase genes showed that the abundance of anammox bacteria varied from 2.3 × 10(5) to 2.2 × 10(6) copies g(-1) soil in the examined soil cores. Correlation analyses suggested that the soil ammonium concentration had significant influence on the activity of anammox bacteria. On the basis of (15)N tracing technology, it is estimated that a total loss of 31.1 g N m(-2) per year could be linked the anammox process in the examined wetland. PMID:26621804

  5. RNA-Based Stable Isotope Probing and Isolation of Anaerobic Benzene-Degrading Bacteria from Gasoline-Contaminated Groundwater

    PubMed Central

    Kasai, Yuki; Takahata, Yoh; Manefield, Mike; Watanabe, Kazuya

    2006-01-01

    Stable isotope probing (SIP) of benzene-degrading bacteria in gasoline-contaminated groundwater was coupled to denaturing gradient gel electrophoresis (DGGE) of DNA fragments amplified by reverse transcription-PCR from community 16S rRNA molecules. Supplementation of the groundwater with [13C6]benzene together with an electron acceptor (nitrate, sulfate, or oxygen) showed that a phylotype affiliated with the genus Azoarcus specifically appeared in the 13C-RNA fraction only when nitrate was supplemented. This phylotype was also observed as the major band in DGGE analysis of bacterial 16S rRNA gene fragments amplified by PCR from the gasoline-contaminated groundwater. In order to isolate the Azoarcus strains, the groundwater sample was streaked on agar plates containing nonselective diluted CGY medium, and the DGGE analysis was used to screen colonies formed on the plates. This procedure identified five bacterial isolates (from 60 colonies) that corresponded to the SIP-identified Azoarcus phylotype, among which two strains (designated DN11 and AN9) degraded benzene under denitrifying conditions. Incubation of these strains with [14C]benzene showed that the labeled carbon was mostly incorporated into 14CO2 within 14 days. These results indicate that the Azoarcus population was involved in benzene degradation in the gasoline-contaminated groundwater under denitrifying conditions. We suggest that RNA-based SIP identification coupled to phylogenetic screening of nonselective isolates facilitates the isolation of enrichment/isolation-resistant microorganisms with a specific function. PMID:16672506

  6. Naturally occurring arsenic in the groundwater at the Kansas City Plant

    SciTech Connect

    Korte, N.E.

    1990-12-01

    This report describes an investigation concerning the presence of arsenic in concentrations exceeding 0.4 mg/L in the groundwater under the Department of Energy's Kansas City Plant (KCP). The study consisted of four distinct phases: a thorough review of the technical literature, a historical survey of arsenic use at the facility, a laboratory study of existing techniques for determining arsenic speciation, and a field program including water, soil, and sediment sampling. The historical survey and literature review demonstrated that plant activities had not released significant quantities of arsenic to the environment but that similar occurrences of arsenic in alluvial groundwater are widespread in the midwestern United States. Laboratory studies showed that a chromatographic separation technique was necessary to accurately determine arsenic speciation for the KCP groundwater samples. Field studies revealed that naturally occurring reducing conditions prevalent in the subsurface are responsible for dissolving arsenic previously sorbed by iron oxides. Indeed, the data demonstrated that the bulk arsenic concentration of site subsoils and sediments is {approximately}7 mg/kg, whereas the arsenic content of iron oxide subsamples is as high as 84 mg/kg. Literature showed that similar concentrations of arsenic in sediments occur naturally and are capable of producing the levels of arsenic found in groundwater monitoring wells at the KCP. The study concludes, therefore, that the arsenic present in the KCP groundwater is the result of natural phenomena. 44 refs., 8 figs., 14 tabs.

  7. Measuring the value of groundwater and other forms of natural capital.

    PubMed

    Fenichel, Eli P; Abbott, Joshua K; Bayham, Jude; Boone, Whitney; Haacker, Erin M K; Pfeiffer, Lisa

    2016-03-01

    Valuing natural capital is fundamental to measuring sustainability. The United Nations Environment Programme, World Bank, and other agencies have called for inclusion of the value of natural capital in sustainability metrics, such as inclusive wealth. Much has been written about the importance of natural capital, but consistent, rigorous valuation approaches compatible with the pricing of traditional forms of capital have remained elusive. We present a guiding quantitative framework enabling natural capital valuation that is fully consistent with capital theory, accounts for biophysical and economic feedbacks, and can guide interdisciplinary efforts to measure sustainability. We illustrate this framework with an application to groundwater in the Kansas High Plains Aquifer, a rapidly depleting asset supporting significant food production. We develop a 10-y time series (1996-2005) of natural capital asset prices that accounts for technological, institutional, and physical changes. Kansas lost approximately $110 million per year (2005 US dollars) of capital value through groundwater withdrawal and changes in aquifer management during the decade spanning 1996-2005. This annual loss in wealth is approximately equal to the state's 2005 budget surplus, and is substantially more than investments in schools over this period. Furthermore, real investment in agricultural capital also declined over this period. Although Kansas' depletion of water wealth is substantial, it may be tractably managed through careful groundwater management and compensating investments in other natural and traditional assets. Measurement of natural capital value is required to inform management and ongoing investments in natural assets. PMID:26858431

  8. Measuring the value of groundwater and other forms of natural capital

    PubMed Central

    Fenichel, Eli P.; Abbott, Joshua K.; Bayham, Jude; Boone, Whitney; Haacker, Erin M. K.; Pfeiffer, Lisa

    2016-01-01

    Valuing natural capital is fundamental to measuring sustainability. The United Nations Environment Programme, World Bank, and other agencies have called for inclusion of the value of natural capital in sustainability metrics, such as inclusive wealth. Much has been written about the importance of natural capital, but consistent, rigorous valuation approaches compatible with the pricing of traditional forms of capital have remained elusive. We present a guiding quantitative framework enabling natural capital valuation that is fully consistent with capital theory, accounts for biophysical and economic feedbacks, and can guide interdisciplinary efforts to measure sustainability. We illustrate this framework with an application to groundwater in the Kansas High Plains Aquifer, a rapidly depleting asset supporting significant food production. We develop a 10-y time series (1996−2005) of natural capital asset prices that accounts for technological, institutional, and physical changes. Kansas lost approximately $110 million per year (2005 US dollars) of capital value through groundwater withdrawal and changes in aquifer management during the decade spanning 1996–2005. This annual loss in wealth is approximately equal to the state’s 2005 budget surplus, and is substantially more than investments in schools over this period. Furthermore, real investment in agricultural capital also declined over this period. Although Kansas’ depletion of water wealth is substantial, it may be tractably managed through careful groundwater management and compensating investments in other natural and traditional assets. Measurement of natural capital value is required to inform management and ongoing investments in natural assets. PMID:26858431

  9. Natural background concentrations and threshold values of chemical species for groundwater in Korea

    NASA Astrophysics Data System (ADS)

    Hyun, Y.; Lee, S.; Lee, H.

    2014-12-01

    We analyze natural background concentrations and determine threshold values of chemical species (NO3-N, Cl, As, Pb, Cr) for groundwater using Groundwater Quality Monitoring Network (GQMN) data operated by Korea Ministry of Environment (ME). GQMN data are divided into two groups, A and B. Group A consists of samples collected in aquifers where anthropogenic inputs are forced to be excluded by aquifer typology. Group B consists of samples in aquifers where purely anthropogenic chemicals (e.g., pesticide, PAC) are introduced at the downgradient. Group A is used to derive nationwide natural background concentrations for groundwater in specific aquifer geology under concern, which represents a reference system. Group B is used for deriving site-specific background concentrations for groundwater. For both groups of data, the samples with anthropogenic inputs are forced to be excluded, thus background concentrations are derived based on a pre-selection method accordingly. We determine threshold values according to EU GroundWater Daughter Directive(GWDD 2006/11/EC). For As, Pb, and Cr and some other trace elements, survival analyses are used for estimating background concentrations due to non-detect data. The results show that high concentration values of NO3-N and Cr are related to high natural background concentrations due to rock-water interactions for Group A. In particular, NO3-N concentrations vary with depth, which are consistent with natural attenuation processes. For Group B, some anthropogenic chemical species such as BTEX are observed and site-specific background concentrations of those elements are non-zero, which is apparently not naturally occurred at all. Natural background concentrations and threshold values derived from Group A can be used for setting up reference values for managing groundwater quality on a level of either domestic or drinking water stands. Meanwhile results from Group B provide a useful guidance for managing groundwater quality in

  10. Isotopic Composition of Natural Nitrate in Groundwater in Los Alamos, New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Chrystal, A. E.; Heikoop, J. M.; Longmire, P.; Dale, M.; Larson, T. E.; Perkins, G.; Fabyrka-Martin, J.; Simmons, A. M.; Fessenden-Rahn, J.

    2009-12-01

    Los Alamos National Laboratory (LANL) has established background concentrations for various dissolved constituents in local groundwater from perched-intermediate and regional aquifers in the vicinity of Los Alamos in north-central New Mexico. Typical background concentrations of nitrate (NO3-) are on the order of 0.31 mg/L as N (0.02 mM/L). In addition to natural sources, anthropogenic sources of NO3- in local groundwaters include industrial and treated sewage discharges released from LANL facilities, and treated sewage effluent discharges from Los Alamos County. We are using stable isotopes of nitrogen and oxygen in NO3- to distinguish among these sources, define groundwater flow paths, and evaluate groundwater mixing. Following the approach of McMahon and Böhlke (2006), we have explored the δ18O[NO3-] of water samples taken from background wells and springs in the Los Alamos area. NO3- from a spring and a well located in the Valles caldera, upgradient and upwind (relative to prevailing winds) of Los Alamos has δ15N and δ18O values of approximately 4.8 ‰ and -2.6 ‰, respectively. Tritium and unadjusted radiocarbon analyses indicate that these caldera waters predate LANL operations commencing in 1943. NO3- from groundwater locations in Los Alamos that exhibit background conditions has isotopic values similar to those of the caldera groundwater. Because local groundwater is relatively oxidizing, denitrification is not expected to be a factor in altering isotopic compositions of NO3-. Results indicate that there is little direct atmospheric contribution to dissolved NO3-, and that most NO3- is derived from bacterial nitrification in which one oxygen atom comes from atmospheric oxygen and two oxygen atoms come from soil porewater. Oxygen isotope values plot slightly below the expected isotopic trend for a 1:2 mix of these two sources, indicating either slight fractionation of oxygen isotopes during nitrification, or potential mixing with geological sources of

  11. Profiling oil sands mixtures from industrial developments and natural groundwaters for source identification.

    PubMed

    Frank, Richard A; Roy, James W; Bickerton, Greg; Rowland, Steve J; Headley, John V; Scarlett, Alan G; West, Charles E; Peru, Kerry M; Parrott, Joanne L; Conly, F Malcolm; Hewitt, L Mark

    2014-01-01

    The objective of this study was to identify chemical components that could distinguish chemical mixtures in oil sands process-affected water (OSPW) that had potentially migrated to groundwater in the oil sands development area of northern Alberta, Canada. In the first part of the study, OSPW samples from two different tailings ponds and a broad range of natural groundwater samples were assessed with historically employed techniques as Level-1 analyses, including geochemistry, total concentrations of naphthenic acids (NAs) and synchronous fluorescence spectroscopy (SFS). While these analyses did not allow for reliable source differentiation, they did identify samples containing significant concentrations of oil sands acid-extractable organics (AEOs). In applying Level-2 profiling analyses using electrospray ionization high resolution mass spectrometry (ESI-HRMS) and comprehensive multidimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF/MS) to samples containing appreciable AEO concentrations, differentiation of natural from OSPW sources was apparent through measurements of O2:O4 ion class ratios (ESI-HRMS) and diagnostic ions for two families of suspected monoaromatic acids (GC × GC-TOF/MS). The resemblance between the AEO profiles from OSPW and from 6 groundwater samples adjacent to two tailings ponds implies a common source, supporting the use of these complimentary analyses for source identification. These samples included two of upward flowing groundwater collected <1 m beneath the Athabasca River, suggesting OSPW-affected groundwater is reaching the river system. PMID:24446583

  12. Apparent pollution of groundwater caused by natural formation of chloroform in forest soils

    NASA Astrophysics Data System (ADS)

    Jacobsen, O.; Laier, T.; Albers, C. N.; Hunkeler, D.

    2011-12-01

    Halogenated compounds are known to be formed in natural environments. Many of these compounds are similar to industrially produced compounds and are toxic or carcinogenic. High concentration of chloroform in groundwater is usually attributed to anthropogenic input, but we have found that the groundwater beneath some pristine areas contained chloroform exceeding 1 μg/L. We investigated four coniferous forests over a period of several years in order to measure the net-formation of chloroform. Field measurements of atmospheric and soil air concentrations of chloroform were monitored. Analyses of soil air at 40 cm depth in different parts of the forests and adjacent areas revealed an extremely large variation in chloroform concentration exceeding two orders of magnitude. Up to 100 ppbv was found in soil air under the spruce forest, to be compared to an ambient atmospheric concentration of 0.02 ppbv. The concentration of chloroform in soil air showed seasonal variation similar to that of CO2. Chloroform formation during incubation of undisturbed top-soil samples was found to be largest in soils from dense conifers stands with well-developed humus layers, while low chloroform formation occurred in soils from beech forest and agricultural grassland. We suggest that the mechanism behind the formation of chloroform is an unspecific chlorination of organic matter, caused by microbial activity in the soil. The aquifers are in fluvio-glacial sands with few layers of silt and a groundwater table from 4 to 7 m below the surface. In the shallowest parts of the aquifer, the groundwater has chloroform concentrations of 0.1 to 5 μg/L, and the groundwater is oxic with an age from 5 to 45 years using CFC-dating. Analyses of oxic groundwater > 40 years showed that it still contained chloroform at concentrations of 1 μg/L. Stable carbon isotopic analyses of chloroform from the uppermost groundwater in different parts of the forests and from soil water showed values from δ13C = -13

  13. Natural attenuation model and biodegradation for 1,1,1-trichloroethane contaminant in shallow groundwater.

    PubMed

    Lu, Qiang; Zhu, Rui-Li; Yang, Jie; Li, Hui; Liu, Yong-Di; Lu, Shu-Guang; Luo, Qi-Shi; Lin, Kuang-Fei

    2015-01-01

    Natural attenuation is an effective and feasible technology for controlling groundwater contamination. This study investigated the potential effectiveness and mechanisms of natural attenuation of 1,1,1-trichloroethane (TCA) contaminants in shallow groundwater in Shanghai by using a column simulation experiment, reactive transport model, and 16S rRNA gene clone library. The results indicated that the majority of the contaminant mass was present at 2-6 m in depth, the contaminated area was approximately 1000 m × 1000 m, and natural attenuation processes were occurring at the site. The effluent breakthrough curves from the column experiments demonstrated that the effectiveness of TCA natural attenuation in the groundwater accorded with the advection-dispersion-reaction equation. The kinetic parameter of adsorption and biotic dehydrochlorination of TCA was 0.068 m(3)/kg and 0.0045 d(-1). The contamination plume was predicted to diminish and the maximum concentration of TCA decreased to 280 μg/L. The bacterial community during TCA degradation in groundwater belonged to Trichococcus, Geobacteraceae, Geobacter, Mucilaginibacter, and Arthrobacter. PMID:26379629

  14. Natural attenuation model and biodegradation for 1,1,1-trichloroethane contaminant in shallow groundwater

    PubMed Central

    Lu, Qiang; Zhu, Rui-Li; Yang, Jie; Li, Hui; Liu, Yong-Di; Lu, Shu-Guang; Luo, Qi-Shi; Lin, Kuang-Fei

    2015-01-01

    Natural attenuation is an effective and feasible technology for controlling groundwater contamination. This study investigated the potential effectiveness and mechanisms of natural attenuation of 1,1,1-trichloroethane (TCA) contaminants in shallow groundwater in Shanghai by using a column simulation experiment, reactive transport model, and 16S rRNA gene clone library. The results indicated that the majority of the contaminant mass was present at 2–6 m in depth, the contaminated area was approximately 1000 m × 1000 m, and natural attenuation processes were occurring at the site. The effluent breakthrough curves from the column experiments demonstrated that the effectiveness of TCA natural attenuation in the groundwater accorded with the advection-dispersion-reaction equation. The kinetic parameter of adsorption and biotic dehydrochlorination of TCA was 0.068 m3/kg and 0.0045 d–1. The contamination plume was predicted to diminish and the maximum concentration of TCA decreased to 280 μg/L. The bacterial community during TCA degradation in groundwater belonged to Trichococcus, Geobacteraceae, Geobacter, Mucilaginibacter, and Arthrobacter. PMID:26379629

  15. Natural vs. artificial groundwater recharge, quantification through inverse modeling

    NASA Astrophysics Data System (ADS)

    Hashemi, H.; Berndtsson, R.; Kompani-Zare, M.; Persson, M.

    2012-08-01

    Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system the recharge volume can be increased even for small flood events while the recharge through the river channel increases only for major flood events.

  16. Natural vs. artificial groundwater recharge, quantification through inverse modeling

    NASA Astrophysics Data System (ADS)

    Hashemi, H.; Berndtsson, R.; Kompani-Zare, M.; Persson, M.

    2013-02-01

    Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady- and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events, the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system, the recharge volume can be increased even for small flood events, while the recharge through the river channel increases only for major flood events.

  17. Anaerobic Digestion and its Applications

    EPA Science Inventory

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  18. Mobilization of arsenic and other naturally occurring contaminants in groundwater of the Main Ethiopian Rift aquifers.

    PubMed

    Rango, Tewodros; Vengosh, Avner; Dwyer, Gary; Bianchini, Gianluca

    2013-10-01

    This study investigates the mechanisms of arsenic (As) and other naturally occurring contaminants (F(-), U, V, B, and Mo) mobilization from Quaternary sedimentary aquifers of the Main Ethiopian Rift (MER) and their enrichment in the local groundwater. The study is based on systematic measurements of major and trace elements as well as stable oxygen and hydrogen isotopes in groundwater, coupled with geochemical and mineralogical analyses of the aquifer rocks. The Rift Valley aquifer is composed of rhyolitic volcanics and Quaternary lacustrine sediments. X-ray fluorescence (XRF) results revealed that MER rhyolites (ash, tuff, pumice and ignimbrite) and sediments contain on average 72 wt. % and 65 wt. % SiO2, respectively. Petrographic studies of the rhyolites indicate predominance of volcanic glass, sanidine, pyroxene, Fe-oxides and plagioclase. The As content in the lacustrine sediments (mean = 6.6 mg/kg) was higher than that of the rhyolites (mean: 2.5 mg/kg). The lacustrine aquifers of the Ziway-Shala basin in the northern part of MER were identified as high As risk zones, where mean As concentration in groundwater was 22.4 ± 33.5 (range of 0.60-190 μg/L) and 54% of samples had As above the WHO drinking water guideline value of 10 μg/L. Field As speciation measurements showed that most of the groundwater samples contain predominantly (~80%) arsenate-As(V) over arsenite-As(III) species. The As speciation together with field data of redox potential (mean Eh = +73 ± 65 mV) and dissolved-O2 (6.6 ± 2.2 mg/L) suggest that the aquifer is predominantly oxidative. Water-rock interactions, including the dissolution of volcanic glass produces groundwater with near-neutral to alkaline pH (range 6.9-8.9), predominance of Na-HCO3 ions, and high concentration of SiO2 (mean: 85.8 ± 11.3 mg/L). The groundwater data show high positive correlation of As with Na, HCO3, U, B, V, and Mo (R(2) > 0.5; p < 0.001). Chemical modeling of the groundwater indicates that Fe-oxides and

  19. Study on Law of Groundwater Evolution under Natural and Artificial Forcing with Case study of Haihe River Basin

    NASA Astrophysics Data System (ADS)

    You, Jinjun; Gan, Hong; Wang, Lin; Bi, Xue; Du, Sisi

    2010-05-01

    The evolution of groundwater is one of the key problems of water cycle study. It is a result of joint effect of natural condition and human activities, but until now the driving forces of groundwater system evolution were not fully understood due to the complexity of groundwater system structures and the uncertainty of affecting factors. Geology, precipitation and human activity are the main factors affecting the groundwater system evolution and interact each other, but the influence of such three factors on groundwater system are not clarified clearly on a macroscopic scale. The precipitation changes the volume of water recharge and the groundwater pumping effect the discharge of groundwater. Another important factor influencing balance of groundwater storage is the underlaying that affects the renewablility of groundwater. The underlaying is decided mainly by geological attributes but also influenced by human activited. The macroscopic environment of groundwater evolves under the natural and anthropic factors. This paper study the general law of groundwater evolution among the factors based on the case study in Haihe River Basin, a typical area with dramatic groundwater change under natural precipitation attenuation and gradually increase of water suuply. Haihe River Basin is located in north-China, covers an area of 320,041 km2 with over 40% plain areas. The plain area of Haihe Basin is densely populated with many large and medium-sized cities, including metropolis of Beijing and Tianjin, and concentrated irrigated areas, playing important roles in China's economy and food production. It is the unique basin where groundwater occupies majority of total water supply in China. Long-term groundwater over-exploitation causes a series of ecological and environmental problems that threats the sustainable development. In this paper, the historical process of groundwater balance in Haihe Basin is divided into three phases by decrease of rainfall and increase of water

  20. Environmental water requirements of groundwater dependent ecosystems: conflict between nature and man

    NASA Astrophysics Data System (ADS)

    Witczak, S.; Kania, J.; Rozanski, K.; Wachniew, P.; Zurek, A.; Dulinski, M.

    2012-04-01

    The presented study was aimed at investigating possible interactions between the porous sandy aquifer intensively exploited for drinking water purposes and the groundwater dependent ecosystem (GDE) consisting of a valuable forest stand. The investigated aquifer (Bogucice Sands) and the associated GDE (Niepolomice Forest) are located in the south of Poland. The aquifer covers the area of ca. 200 km2 and belongs to the category of medium groundwater basins in Poland. The Niepolomice Forest is a lowland forest covering around 110 km2. This relic of once vast forests is protected as a Natura 2000 Special Protection Area "Puszcza Niepolomicka" (PLB120002) that supports bird populations of European importance. Additionally, a fen in the western part of the Niepolomice Forest comprises a separate Natura 2000 area "Torfowisko Wielkie Bloto" (PLH120080), a significant habitat of endangered butterfly species associated with wet meadows. The Niepolomice Forest contains also several nature reserves and the European bison breeding centre and has an important recreational value as the largest forest complex in the vicinity of Krakow. Due to spatially variable lithologies and groundwater levels, the Niepolomice Forest is a mosaic of various forest and non-forest habitats, including wetlands, marsh forests, humid forests and fresh forests. Dependence of the Niepolomice Forest stands on groundwater is enhanced by low available water capacity and low capillary rise of soils in the area. Groundwater conditions in the Niepolomice Forest, including Wielkie Bloto fen have been affected by meliorations carried out mostly in the period 1900-1930 and after the Second World War and by forest management. Due to artesian conditions in the area and relatively thin clay layer separating Tertiary aquifer layers from shallow Quaternary aquifer, the upward leaching of deeper groundwater may contribute in a significant way to the water balance of the investigated GDE. In September 2009 a cluster of

  1. Environmental water requirements of groundwater dependent ecosystems: conflict between nature and man

    NASA Astrophysics Data System (ADS)

    Witczak, S.; Kania, J.; Rozanski, K.; Wachniew, P.; Zurek, A.; Dulinski, M.

    2012-04-01

    The presented study was aimed at investigating possible interactions between the porous sandy aquifer intensively exploited for drinking water purposes and the groundwater dependent ecosystem (GDE) consisting of a valuable forest stand. The investigated aquifer (Bogucice Sands) and the associated GDE (Niepolomice Forest) are located in the south of Poland. The aquifer covers the area of ca. 200 km2 and belongs to the category of medium groundwater basins in Poland. The Niepolomice Forest is a lowland forest covering around 110 km2. This relic of once vast forests is protected as a Natura 2000 Special Protection Area "Puszcza Niepolomicka" (PLB120002) that supports bird populations of European importance. Additionally, a fen in the western part of the Niepolomice Forest comprises a separate Natura 2000 area "Torfowisko Wielkie Bloto" (PLH120080), a significant habitat of endangered butterfly species associated with wet meadows. The Niepolomice Forest contains also several nature reserves and the European bison breeding centre and has an important recreational value as the largest forest complex in the vicinity of Krakow. Due to spatially variable lithologies and groundwater levels, the Niepolomice Forest is a mosaic of various forest and non-forest habitats, including wetlands, marsh forests, humid forests and fresh forests. Dependence of the Niepolomice Forest stands on groundwater is enhanced by low available water capacity and low capillary rise of soils in the area. Groundwater conditions in the Niepolomice Forest, including Wielkie Bloto fen have been affected by meliorations carried out mostly in the period 1900-1930 and after the Second World War and by forest management. Due to artesian conditions in the area and relatively thin clay layer separating Tertiary aquifer layers from shallow Quaternary aquifer, the upward leaching of deeper groundwater may contribute in a significant way to the water balance of the investigated GDE. In September 2009 a cluster of

  2. Evaluation of various organic fertilizer substrates and hydraulic retention times for enhancing anaerobic degradation of explosives-contaminated groundwater while using constructed wetlands at the Milan Army Ammunition Plant, Milan, Tennessee. Final report

    SciTech Connect

    Behrends, L.L.; Almond, R.A.; Kelly, D.A.; Phillips, W.D.; Rogers, W.J.

    1998-05-01

    This document describes studies conducted at the Milan Army Ammunition Plant (MAAP) to improve the design, operation, and cost of gravel-based anaerobic cells when phytoremediating explosives-contaminated groundwater. To conduct this study, small-scale anaerobic test cells were used to determine: (1) If the hydraulic retention time of a large demonstration-scale anaerobic cell at MAAP could be reduced, and (2) if other carbon sources could be used as an anaerobic feedstock. The study results indicated that: (1) The existing anaerobic cell`s 7.5-day retention time should not be reduced since residual explosive by-products were present in the effluent of treatments with a 3.5-day retention time. (2) Daily application of a relatively soluble substrate, such as molasses syrup, will provide better explosives removal than periodic application of less soluble substrates like milk replacement starter and sewage sludge. (3) Molasses syrup could be, and should be, used as a substitute for milk replacement power. The recommendation to use molasses syrup was based on: (1) The lower cost of molasses syrup as compared to milk replacement starter, (2) molasses syrup`s higher solubility (which makes it easier to apply), and (3) molasses syrup`s ability to provide enhanced explosives removal.

  3. Characterization of Ground-Water Quality, Upper Republican Natural Resources District, Nebraska, 1998-2001

    USGS Publications Warehouse

    Frankforter, Jill D.; Chafin, Daniele T.

    2004-01-01

    Nearly all rural inhabitants and livestock in the Upper Republican Natural Resources District (URNRD) in southwestern Nebraska use ground water that can be affected by elevated nitrate concentrations. The development of ground-water irrigation in this area has increased the vulnerability of ground water to the introduction of fertilizers and other agricultural chemicals. In 1998, the U.S. Geological Survey, in cooperation with the Upper Republican Natural Resources District, began a study to characterize the quality of ground water in the Upper Republican Natural Resources District area with respect to physical properties and concentrations of major ions, coliform bacteria, nitrate, and pesticides, and to assess the presence of nitrogen concentrations in the unsaturated zone. At selected well sites, the ground-water characterization also included tritium and nitrogen-isotope analyses to provide information about the approximate age of the ground water and potential sources of nitrogen detected in ground-water samples, respectively. In 1998, ground-water samples were collected from 101 randomly selected domestic-well sites. Of the 101 samples collected, 26 tested positive for total coliform bacteria, exceeding the U.S. Environmental Protection Agency's Maximum Contaminant Level (MCL) of zero colonies. In 1999, ground-water samples were collected from 31 of the 101 well sites, and 16 tested positive for coliform bacteria. Nitrates were detected in ground water from all domestic-well samples and from all but four of the irrigation-well samples collected from 1998 to 2001. Eight percent of the domestic-well samples and 3 percent of the irrigation-well samples had nitrate concentrations exceeding the U.S. Environmental Protection Agency's MCL for drinking water of 10 milligrams per liter. Areas with nitrate concentrations exceeding 6 milligrams per liter, the URNRD's ground-water management-plan action level, were found predominantly in north-central Chase, western and

  4. Analysis of natural ground-water level variations for hydrogeologic conceptualization, Hanford Site, Washington

    NASA Astrophysics Data System (ADS)

    Nevulis, Richard H.; Davis, Donald R.; Sorooshian, Soroosh

    1989-07-01

    This study involves the analysis of groundwater level time series for the purpose of obtaining details for a conceptual hydrogeologic model at a time when conventional hydraulic stress testing was not feasible due to regulatory considerations. The study area is located in south central Washington in the Pasco Basin which was a candidate site for underground disposal of high-level radioactive nuclear wastes. Advantages of such passive methods of analysis may include relative simplicity, low cost, and avoidance of disturbances typically associated with stress testing of aquifers. Through this approach, natural and incidental man-made groundwater level variations, most of which are quite small, are examined by statistical and analytical methods in conjunction with hydrogeologic models to draw inferences on the hydrogeology. Vertical connectivity of the hydrostratigraphic units is also examined by analyzing groundwater level time series of five units at three piezometer nests. It is concluded that a combination of statistical/analytical approaches used in a complementary fashion can provide useful information about the hydrogeology of a given area. A meaningful analysis requires that there is (1) a source of influence on the groundwater levels, (2) a response to that influence, (3) a sufficiently long data record, and (4) measurement and analytical techniques which allow the detection and identification of the influence and response.

  5. Comparison of different methods to assess natural backgrond levels in groundwater bodies in southern Europe

    NASA Astrophysics Data System (ADS)

    Preziosi, Elisabetta; Parrone, Daniele; Ghergo, Stefano; Ducci, Daniela; Sellerino, Mariangela; Condesso de Melo, Maria Teresa; Oliveira, Juana; Ribeiro, Luis

    2014-05-01

    The assessment of the natural background levels (NBLs) of a substance or element is important to distinguish anthropogenic pollution from contamination of natural origin in groundwater bodies. NBLs are the result of different atmospheric, geological, chemical and biological interaction processes during groundwater infiltration and circulation. Rainfall composition, water-rock interactions in both vadose and saturated zone, exchanges with other water bodies and residence time also contribute to determine the groundwater natural composition. Nowadays there are different methods to assess NBLs but the main concern is that they may provide different results. In the European legislative context, the Groundwater Directive (2006/118/EC) requests to EU Member States to derive appropriate threshold values (TV) for several potentially harmful substances, taking into account NBLs when necessary, in order to assess the chemical status of groundwater bodies. In the framework of a common project between Italy (CNR) and Portugal (FCT), several groundwater bodies were taken into account in different regions of Italy (Latium and Campania) and Portugal. The general objective is the definition of a sound comprehensive methodology for NBL assessment at groundwater body scale, suitable to different hydrogeological settings through comparing diverse case studies and different approaches. The Italian case studies are located in volcanic or volcano-sedimentary geological contexts, where high concentrations of substances such as As, F, Fe, Mn among others in groundwater are well known. The Portuguese case studies are located in carbonate and porous media aquifers. Several data sets were explored with the use of statistical as well as mathematical procedures in order to determine a threshold between natural and anthropogenic concentration. Today essentially two groups of methods are proposed, the first ascribed to the probability plots (PP method), the second based on the selection of the

  6. Natural background groundwater composition in the Azores archipelago (Portugal): a hydrogeochemical study and threshold value determination.

    PubMed

    Cruz, J V; Andrade, C

    2015-07-01

    Groundwater discharges were sampled in selected springs from São Miguel (Furnas and Fogo trachytic central volcanoes) and Santa Maria islands (Azores, Portugal), in order to characterize natural background levels (NBLs) and proceed to the determination of threshold values (TVs). Besides being a key issue in order to fully assess the anthropogenic pressures, NBLs are also instrumental to derive TVs, therefore complying with requirements from the European Union Groundwater Directive. The composition of groundwater corresponds mainly to low mineralized Na-HCO3 to Na-Cl water types, the latter dominant in Santa Maria island, with a decreasing order of Na>Ca>Mg>K and Cl>HCO3>SO4>NO3 for cations and anion respectively. The majority of the samples are slightly acid to slightly alkaline (pH range of 5.45-7.43), and the electrical conductivity range between 180 and 1458 μS/cm. Groundwater composition is controlled by two major drivers, addition of sea salts and dissolution of silicate minerals. Results shown that TVs established along the present study are in general in the lower rank when compared to the range of values proposed by the several EU member states, with the main exception of NO3, reflecting the impact of agriculture activities over water quality in the Azores, and lower than the national ones. The comparison between the estimated NBL and TV with values derived with another dataset from the Azores, usually higher, depicts the effect of a larger and diverse number of groundwater sources over calculations. On the other hand, all samples which show a contribution from volcanic/hydrothermal systems were excluded from the dataset, which explains why the derived NBLs and TVs are lower comparing to other active volcanic areas, which is also a conservative approach on a subject that has regulatory implications. PMID:25813965

  7. Natural attenuation processes for remediation of arsenic contaminated soils and groundwater.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2006-12-01

    Arsenic (As) contamination presents a hazard in many countries. Natural attenuation (NA) of As-contaminated soils and groundwater may be a cost-effective in situ remedial option. It relies on the site intrinsic assimilative capacity and allows in-place cleanup. Sorption to solid phases is the principal mechanism immobilizing As in soils and removing it from groundwater. Hydroxides of iron, aluminum and manganese, clay and sulfide minerals, and natural organic matter are commonly associated with soils and aquifer sediments, and have been shown to be significant As adsorbents. The extent of sorption is influenced by As speciation and the site geochemical conditions such as pH, redox potential, and the co-occurring ions. Microbial activity may catalyze the transformation of As species, or mediate redox reactions thus influencing As mobility. Plants that are capable of hyperaccumulating As may translocate As from contaminated soils and groundwater to their tissues, providing the basis for phytoremediation. However, NA is subject to hydrological changes and may take substantial periods of time, thus requiring long-term monitoring. The current understanding of As NA processes remains limited. Sufficient site characterization is critical to the success of NA. Further research is required to develop conceptual and mathematical models to predict the fate and transport of As and to evaluate the site NA capacity. Engineering enhanced NA using environmentally benign products may be an effective alternative. PMID:17049728

  8. The nature and role of physical models in enhancing sixth grade students' mental models of groundwater and groundwater processes

    NASA Astrophysics Data System (ADS)

    Duffy, Debra Lynne Foster

    Through a non-experimental descriptive and comparative mixed-methods approach, this study investigated the experiences of sixth grade earth science students with groundwater physical models through an extended SE learning cycle format. The data collection was based on a series of quantitative and qualitative research tools intended to investigate students' ideas and changes in ideas rather than measure their achievement. The measures included a groundwater survey, classroom observations, and one-on-one follow-up student interviews for triangulation of data sources. The research was carried out at a K-12 independent school in eastern Virginia using two classes of sixth grade earth science students (n=30). The findings suggest that physical models help students identify the components porosity and permeability with respect to water flow in groundwater systems. Higher levels of system thinking were best demonstrated in model components that allowed students to experience groundwater pollution activities and pumping groundwater wells. However, the results also indicated that due to model constraints, students can develop misconceptions during the use of physical models, specifically more complex physical models as in the Groundwater Exploration Activity Model. A pure discovery learning format while using physical models without guidance or formative assessment probes can lead to misconceptions about groundwater processes as well as confusion between model attributes and real world groundwater systems. The implications of this study relate directly to the inclusion of groundwater in the new national science standards released in 2011; A Framework for K-12 Science Standard; Practices, Crosscutting Concepts, and Core Ideas (NRC, 2011). The new national standards, as in other educational reform efforts, will have the ability to affect curricular and instructional strategies in science education. From the results of this study, it was concluded that best practices for using

  9. Natural Attenuation Software (NAS): A computer program for estimating remediation times of contaminated groundwater

    USGS Publications Warehouse

    Mendez, E.; Widdowson, M.; Brauner, S.; Chapelle, F.; Casey, C.

    2004-01-01

    This paper describes the development and application of a modeling system called Natural Attenuation Software (NAS). NAS was designed as a screening tool to estimate times of remediation (TORs), associated with monitored natural attenuation (MNA), to lower groundwater contaminant concentrations to regulatory limits. Natural attenuation processes that NAS models include advection, dispersion, sorption, biodegradation, and non-aqueous phase liquid (NAPL) dissolution. This paper discusses the three main interactive components of NAS: 1) estimation of the target source concentration required for a plume extent to contract to regulatory limits, 2) estimation of the time required for NAFL contaminants in the source area to attenuate to a predetermined target source concentration, and 3) estimation of the time required for a plume extent to contract to regulatory limits after source reduction. The model's capability is illustrated by results from a case study at a MNA site, where NAS time of remediation estimates compared well with observed monitoring data over multiple years.

  10. The role of groundwater governance in emergencies during different phases of natural disasters

    NASA Astrophysics Data System (ADS)

    Vrba, Jaroslav

    2016-03-01

    The establishment of water governance in emergency situations supports timely and effective reaction with regard to the risk and impact of natural disasters on drinking-water supplies and populations. Under such governance, emergency activities of governmental authorities, rescue and aid teams, water stakeholders, local communities and individuals are coordinated with the objective to prevent and/or mitigate disaster impact on water supplies, to reduce human suffering due to drinking-water failure during and in the post-disaster period, and to manage drinking-water services in emergency situations in an equitable manner. The availability of low-vulnerability groundwater resources that have been proven safe and protected by geological features, and with long residence time, can make water-related relief and rehabilitation activities during and after an emergency more rapid and effective. Such groundwater resources have to be included in water governance and their exploration must be coordinated with overall management of drinking-water services in emergencies. This paper discusses institutional and technical capacities needed for building effective groundwater governance policy and drinking-water risk and demand management in emergencies. Disaster-risk mitigation plans are described, along with relief measures and post-disaster rehabilitation and reconstruction activities, which support gradual renewal of drinking-water services on the level prior to the disaster. The role of groundwater governance in emergencies differs in individual phases of disaster (preparedness, warning, impact/relief, rehabilitation). Suggested activities and actions associated with these phases are summarized and analysed, and a mode of their implementation is proposed.

  11. Application of first order kinetics to characterize MTBE natural attenuation in groundwater

    NASA Astrophysics Data System (ADS)

    Metcalf, Meredith J.; Stevens, Graham J.; Robbins, Gary A.

    2016-04-01

    Methyl tertiary butyl ether (MTBE) was a gasoline oxygenate that became widely used in reformulated gasoline as a means to reduce air pollution in the 1990s. Unfortunately, many of the underground storage tanks containing reformulated gasoline experienced subsurface releases which soon became a health concern given the increase in public and private water supplies containing MTBE. Many states responded to this by banning the use of MTBE as an additive, including Connecticut. Although MTBE dissipates by natural attenuation, it continues to be prevalent in groundwater long after the Connecticut ban in 2004. This study estimated the rate of the natural attenuation in groundwater following the Connecticut ban by evaluating the MTBE concentration two years prior to and two years after the MTBE ban at eighty-three monitoring wells from twenty-two retail gasoline stations where MTBE contamination was observed. Sites chosen for this study had not undergone active remediation ensuring no artificial influence to the natural attenuation processes that controls the migration and dissipation of MTBE. Results indicate that MTBE has dissipated in the natural environment, at more than 80% of the sites and at approximately 82% of the individual monitoring wells. In general, dissipation approximated first order kinetics. Dissipation half-lives, calculated using concentration data from the two year period after the ban, ranged from approximately three weeks to just over seven years with an average half-life of 7.3 months with little variability in estimates for different site characteristics. The accuracy of first order estimates to predict further MTBE dissipation were tested by comparing predicted concentrations with those observed after the two year post-ban period; the predicted concentrations closely match the observed concentrations which supports the use of first order kinetics for predictions of this nature.

  12. Application of first order kinetics to characterize MTBE natural attenuation in groundwater.

    PubMed

    Metcalf, Meredith J; Stevens, Graham J; Robbins, Gary A

    2016-04-01

    Methyl tertiary butyl ether (MTBE) was a gasoline oxygenate that became widely used in reformulated gasoline as a means to reduce air pollution in the 1990s. Unfortunately, many of the underground storage tanks containing reformulated gasoline experienced subsurface releases which soon became a health concern given the increase in public and private water supplies containing MTBE. Many states responded to this by banning the use of MTBE as an additive, including Connecticut. Although MTBE dissipates by natural attenuation, it continues to be prevalent in groundwater long after the Connecticut ban in 2004. This study estimated the rate of the natural attenuation in groundwater following the Connecticut ban by evaluating the MTBE concentration two years prior to and two years after the MTBE ban at eighty-three monitoring wells from twenty-two retail gasoline stations where MTBE contamination was observed. Sites chosen for this study had not undergone active remediation ensuring no artificial influence to the natural attenuation processes that controls the migration and dissipation of MTBE. Results indicate that MTBE has dissipated in the natural environment, at more than 80% of the sites and at approximately 82% of the individual monitoring wells. In general, dissipation approximated first order kinetics. Dissipation half-lives, calculated using concentration data from the two year period after the ban, ranged from approximately three weeks to just over seven years with an average half-life of 7.3 months with little variability in estimates for different site characteristics. The accuracy of first order estimates to predict further MTBE dissipation were tested by comparing predicted concentrations with those observed after the two year post-ban period; the predicted concentrations closely match the observed concentrations which supports the use of first order kinetics for predictions of this nature. PMID:26878650

  13. Impact of human activity and natural processes on groundwater arsenic in an urbanized area (South China) using multivariate statistical techniques.

    PubMed

    Huang, Guanxing; Chen, Zongyu; Liu, Fan; Sun, Jichao; Wang, Jincui

    2014-11-01

    Anthropogenic factors resulted from the urbanization may affect the groundwater As in urbanized areas. Groundwater samples from the Guangzhou city (South China) were collected for As and other parameter analysis, in order to assess the impact of urbanization and natural processes on As distribution in aquifers. Nearly 25.5 % of groundwater samples were above the WHO drinking water standard for As, and the As concentrations in the granular aquifer (GA) were generally far higher than that in the fractured bedrock aquifer (FBA). Samples were classified into four clusters by using hierarchical cluster analysis. Cluster 1 is mainly located in the FBA and controlled by natural processes. Anthropogenic pollution resulted from the urbanization is responsible for high As concentrations identified in cluster 2. Clusters 3 and 4 are mainly located in the GA and controlled by both natural processes and anthropogenic factors. Three main mechanisms control the source and mobilization of groundwater As in the study area. Firstly, the interaction of water and calcareous rocks appears to be responsible for As release in the FBA. Secondly, reduction of Fe/Mn oxyhydroxides and decomposition of organic matter are probably responsible for high As concentrations in the GA. Thirdly, during the process of urbanization, the infiltration of wastewater/leachate with a high As content is likely to be the main source for groundwater As, while NO3 (-) contamination diminishes groundwater As. PMID:24996949

  14. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests.

    PubMed Central

    Smith, R L; Howes, B L; Garabedian, S P

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A Vmax for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional adevection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The Km values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 microM for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems. PMID:1892389

  15. Dating young groundwater with sulfur hexafluoride: Natural and anthropogenic sources of sulfur hexafluoride

    USGS Publications Warehouse

    Busenberg, E.; Plummer, L.N.

    2000-01-01

    Sulfur hexafluoride (SF6) is primarily of anthropogenic origin but also occurs naturally. The troposphere concentration of SF6 has increased from a steady state value of 0.054 ?? 0.009 to more than 4 parts per trillion volume during the past 40 years. An analytical procedure was developed for measuring concentrations of SF6 to less than 0.01 fmol/L in water. Groundwater can be dated with SF6 if it is in equilibrium with atmospheric SF6 at the time of recharge and does not contain significant SF6 from other sources. The dating range of SF6 is currently 0 to 30 years. The tracer was successfully used to date shallow groundwater of the Atlantic Coastal Plain sand aquifers of the United States and springs issuing near the top of the Blue Ridge Mountains of Virginia. Significant concentrations of naturally occurring SF6 were found in some igneous, volcanic, and sedimentary rocks and in some hydrothermal fluids.

  16. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests

    USGS Publications Warehouse

    Smith, R.L.; Howes, B.L.; Garabedian, S.P.

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluoroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A V(max) for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional advection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The K(m) values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 ??M for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems.

  17. Natural and anthropogenic factors affecting the groundwater quality in the Nandong karst underground river system in Yunan, China

    NASA Astrophysics Data System (ADS)

    Jiang, Yongjun; Wu, Yuexia; Groves, Chris; Yuan, Daoxian; Kambesis, Pat

    2009-10-01

    The Nandong Underground River System (NURS) is located in a typical karst agriculture dominated area in the southeast Yunnan Province, China. Groundwater plays an important role for social and economical development in the area. However, with the rapid increase in population and expansion of farm land, groundwater quality has degraded. 42 groundwater samples collected from springs in the NURS showed great variation of chemical compositions across the study basin. With increased anthropogenic contamination in the area, the groundwater chemistry has changed from the typical Ca-HCO 3 or Ca (Mg)-HCO 3 type in karst groundwater to the Ca-Cl (+ NO 3) or Ca (Mg)-Cl (+ NO 3), and Ca-Cl (+ NO 3 + SO 4) or Ca (Mg)-Cl (+ NO 3 + SO 4) type, indicating increases in NO 3-, Cl - and SO 42- concentrations that were caused most likely by human activities in the region. This study implemented the R-mode factor analysis to investigate the chemical characteristics of groundwater and to distinguish the natural and anthropogenic processes affecting groundwater quality in the system. The R-mode factor analysis together with geology and land uses revealed that: (a) contamination from human activities such as sewage effluents and agricultural fertilizers; (b) water-rock interaction in the limestone-dominated system; and (c) water-rock interaction in the dolomite-dominated system were the three major factors contributing to groundwater quality. Natural dissolution of carbonate rock (water-rock interaction) was the primary source of Ca 2+ and HCO 3- in groundwater, water-rock interaction in dolomite-dominated system resulted in higher Mg 2+ in the groundwater, and human activities were likely others sources. Sewage effluents and fertilizers could be the main contributor of Cl -, NO 3-, SO 42-, Na + and K + to the groundwater system in the area. This study suggested that both natural and anthropogenic processes contributed to chemical composition of groundwater in the NURS, human activities

  18. Evaluation of Natural Attenuation as One Component of Chloroethene-Contaminated Groundwater Remediation

    SciTech Connect

    Sorenson, K.S.; Peterson, L.N.; Green, T.S.

    1998-10-01

    Test Area North (TAN) at the Idaho National Engineering and Environmental Laboratory (INEEL) is the site of a large trichloroethene (TCE) plume resulting from the historical injection of wastewater into the Snake River Plain Aquifer. The TAN Record of Decision (ROD) selected pump and treat as the final remedy and included a contingency for post-ROD treatability studies of alternative technologies. The technologies still under consideration are in situ bioremediation, in situ chemical oxidation, and natural attenuation. Both anaerobic and aerobic laboratory microcosm studies indicate the presence of microorganisms capable of chloroethene degradation. Field data indicate that TCE concentrations decrease relative to tritium and tetrachloroethene indicating an as yet unknown process is contributing to natural attenuation of TCE. Several methods for analyzing the field data have been evaluated and important limitations identified. Early results from the continued evaluation of the three alternative technologies suggest the combined approach of active remediation of the source area (in situ bioremediation and/or chemical oxidation replacing or augmenting pump and treat) and natural attenuation within the dissolved phase plume may be more cost and schedule effective than the base case pump and treat.

  19. Evaluation of Natural Attenuation as One Component of Chloroethene-Contaminated Groundwater Remediation

    SciTech Connect

    K.S. Sorenson; L.N. Peterson; T.S. Green

    1998-10-01

    Test Area North (TAN) at the Idaho National Engineering and Environmental Laboratory (INEEL) is the site of a large trichloroethene (TCE) plume resulting from the historical injection of wastewater into the Snake River Plain Aquifer. The TAN Record of Decision (ROD) selected pump and treat as the final remedy and included a contingency for post-ROD treatability studies of alternative technologies. The technologies still under consideration are in-situ bioremediation, in-situ chemical oxidation, and natural attenuation. Both anaerobic and aerobic laboratory microcosm studies indicate the presence of microorganisms capable of chloroethene degradation. Field data indicate that TCE concentrations decrease relative to tritium and tetrachloroethene indicating an as yet unknown process is contributing to natural attenuation of TCE. Several methods for analyzing the field data have been evaluated and important limitations identified. Early results from the continued evaluation of the three alternative technologies suggest the combined approach of active remediation of the source area (in situ bioremediation and/or chemical oxidation replacing or augmenting pump and treat) and natural attenuation within the dissolved phase plume may be more cost and schedule effective than the base case pump and treat.

  20. Tracing natural gas transport into shallow groundwater using dissolved nitrogen and alkane chemistry in Parker County, Texas

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Dissolved methane in shallow groundwater drives public concern about the safety of hydraulic fracturing. We report dissolved alkane and nitrogen gas concentrations and their stable isotope values (δ13C and δ15N, respectively) from 208 water wells in Parker county, Texas. These data are used to differentiate 'stray' natural gas and low temperature microbial methane, and (2) estimate the ratio of stray gas to groundwater. The ratio of (gas-phase) stray natural gas to groundwater is estimated by correlating dissolved methane and nitrogen concentrations and dissolved nitrogen δ15N values. Our hypothesis is groundwater exposed to high volumes of stray natural gas have high dissolved methane concentrations and low dissolved nitrogen concentrations and δ15N values. Alternatively, groundwater exposed to low volumes of stray gas-phase natural gas have elevated dissolved methane, but the concentration of dissolved nitrogen and its d15N value is atmospheric. A cluster of samples in Parker county have high concentrations of dissolved methane (>10mg/L) with d13Cmethane and alkane ratios (C1/C2+C3) typical of natural gas from the Barnett Shale and the Strawn Formation. Coupling dissolved nitrogen concentrations and δ15N values with these results, we suggest that few of the wells in this cluster preserve large gas to water ratios. Many samples with high dissolved methane concentrations have atmospheric dissolved nitrogen concentrations and δ15N values, providing evidence against high flux natural gas transport into shallow groundwater. These results demonstrate that dissolved nitrogen chemistry, in addition to dissolved alkane and noble gas measurements, may be useful to discern sources of dissolved methane and estimate ratios of stray natural gas-water ratios.

  1. POSTCLOSURE GROUNDWATER REMEDIATION AND MONITORING AT THE SANITARY LANDFILL, SAVANNAH RIVER SITE TRANSITIONING TO MONITORED NATURAL ATTENUATION

    SciTech Connect

    Ross, J; Walt Kubilius, W; Thomas Kmetz, T; D Noffsinger, D; Karen M Adams, K

    2006-11-17

    Resource Conservation and Recovery Act (RCRA) requirements for hazardous waste facilities include 30 years of post-closure monitoring. The use of an objective-based monitoring strategy allows for a significant reduction in the amount of groundwater monitoring required, as the groundwater remediation transitions from an active biosparging system to monitored natural attenuation. The lifecycle of groundwater activities at the landfill has progressed from detection monitoring and plume characterization, to active groundwater remediation, and now to monitored natural attenuation and postclosure monitoring. Thus, the objectives of the groundwater monitoring have changed accordingly. Characterization monitoring evaluated what biogeochemical natural attenuation processes were occurring and determined that elevated levels of radium were naturally occurring. Process monitoring of the biosparging system required comprehensive sampling network up- and down-gradient of the horizontal wells to verify its effectiveness. Currently, the scope of monitoring and reporting can be significantly reduced as the objective is to demonstrate that the alternate concentration limits (ACL) are being met at the point of compliance wells and the maximum contaminant level (MCL) is being met at the surface water point of exposure. The proposed reduction is estimated to save about $2M over the course of the remaining 25 years of postclosure monitoring.

  2. Greenhouse gases generated from the anaerobic biodegradation of natural offshore asphalt seepages in southern California

    USGS Publications Warehouse

    Lorenson, T.D.; Wong, Florence L.; Dartnell, Peter; Sliter, Ray W.

    2014-01-01

    Significant offshore asphaltic deposits with active seepage occur in the Santa Barbara Channel offshore southern California. The composition and isotopic signatures of gases sampled from the oil and gas seeps reveal that the coexisting oil in the shallow subsurface is anaerobically biodegraded, generating CO2 with secondary CH4 production. Biomineralization can result in the consumption of as much as 60% by weight of the original oil, with 13C enrichment of CO2. Analyses of gas emitted from asphaltic accumulations or seeps on the seafloor indicate up to 11% CO2 with 13C enrichment reaching +24.8‰. Methane concentrations range from less than 30% up to 98% with isotopic compositions of –34.9 to –66.1‰. Higher molecular weight hydrocarbon gases are present in strongly varying concentrations reflecting both oil-associated gas and biodegradation; propane is preferentially biodegraded, resulting in an enriched 13C isotopic composition as enriched as –19.5‰. Assuming the 132 million barrels of asphaltic residues on the seafloor represent ~40% of the original oil volume and mass, the estimated gas generated is 5.0×1010 kg (~76×109 m3) CH4 and/or 1.4×1011 kg CO2 over the lifetime of seepage needed to produce the volume of these deposits. Geologic relationships and oil weathering inferences suggest the deposits are of early Holocene age or even younger. Assuming an age of ~1,000 years, annual fluxes are on the order of 5.0×107 kg (~76×106 m3) and/or 1.4×108 kg for CH4 and CO2, respectively. The daily volumetric emission rate (2.1×105 m3) is comparable to current CH4 emission from Coal Oil Point seeps (1.5×105 m3/day), and may be a significant source of both CH4 and CO2 to the atmosphere provided that the gas can be transported through the water column.

  3. InSAR analysis of natural recharge to define structure of a ground-water basin, San Bernardino, California

    USGS Publications Warehouse

    Lu, Zhiming; Danskin, W.R.

    2001-01-01

    Using interferometric synthetic aperture radar (InSAR) analysis of ERS-1 and ERS-2 images, we detect several centimeters of uplift during the first half of 1993 in two areas of the San Bernardino ground-water basin of southern California. This uplift correlates with unusually high runoff from the surrounding mountains and increased ground-water levels in nearby wells. The deformation of the land surface identifies the location of faults that restrict ground-water flow, maps the location of recharge, and suggests the areal distribution of fine-grained aquifer materials. Our preliminary results demonstrate that naturally occurring runoff and resultant recharge can be used with interferometric deformation mapping to help define the structure and important hydrogeologic features of a ground-water basin. This approach may be particularly useful in investigations of remote areas with scant ground-based hydrogeologic data.

  4. Bioelectricity generation in microbial fuel cell using natural microflora and isolated pure culture bacteria from anaerobic palm oil mill effluent sludge.

    PubMed

    Nor, Muhamad Hanif Md; Mubarak, Mohd Fahmi Muhammad; Elmi, Hassan Sh Abdirahman; Ibrahim, Norahim; Wahab, Mohd Firdaus Abdul; Ibrahim, Zaharah

    2015-08-01

    A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m(2) and 91.12mA/m(2) respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m(2) and 654.90mA/m(2) respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge. PMID:25799955

  5. Evidence on Anaerobic Methane Oxidation (AOM) in a boreal cultivated peatland with natural and added electron acceptors

    NASA Astrophysics Data System (ADS)

    Dorodnikov, Maxim; Silvennoinen, Hanna; Martikainen, Pertti; Dörsch, Peter

    2015-04-01

    Anaerobic oxidation of methane (AOM) is a process of methane (CH4) consumption under anoxic conditions driven by microorganisms, which oxidize CH4 with various alternate electron acceptors (AEA): sulfate, nitrate, nitrite, metals-(Fe, Mn, Cu), organic compounds. AOM is common in marine ecosystems, where microbial sulfate reduction (SR) consumes most of the CH4 produced in sediments. Despite the global significance of AOM, the exact mechanisms and relevance of the process in terrestrial ecosystems are almost unknown. In the current study the occurrence of AOM was tested for two organic soil horizons (30 and 40 cm depth) and one mineral sub-soil (sand, 50 cm depth) of a cultivated boreal peatland (Linnansuo, Eastern Finland, energy crop Phalaris arundinacea - reed canarygrass) under controlled conditions with the addition of 13C-labeled CH4 and two common AEAs - SO4-2 and Fe+3. Concentrations of CH4, CO2 and O2 were continuously measured during 10 days of incubation and CO2 was sampled periodically under anaerobic conditions for stable 13C analysis. Oxygen dynamics revealed negligible O2 contamination during incubation and its trace amounts (0.05-0.8% from the atmospheric) were accounted in the net CH4 uptake. Application of 13C-enriched CH4 (4.9 atom%) allowed to track the label in CO2 as the end-product of AOM. The highest 13CO2 enrichment (up to 60‰) was observed in mineral sub-soil, however AOM was quantitatively more pronounced in the upper 30 cm horizon (2.1 vs. 0.2 μg CO2 g soil DW-1 in the 50 cm sub-soil). The highest AOM rate of 8.9 ng CO2 g soil DW-1 h-1 was estimated for the control treatment where no AEAs were added indicating sufficient amount of naturally available AEAs, likely organic compounds. This rate was 50 times more intensive (on the C basis) than the CH4 production potential of the same soil. In contrast, external AEAs decreased AOM rates but added Fe+3 stimulated decomposition of native SOM (as seen from the most depleted 13CO2 signatures

  6. Magnetic properties of iron minerals produced by natural iron- and manganese-reducing groundwater bacteria

    NASA Astrophysics Data System (ADS)

    Abrajevitch, Alexandra; Kondratyeva, Lubov M.; Golubeva, Evgeniya M.; Kodama, Kazuto; Hori, Rie S.

    2016-08-01

    Understanding the contribution of biogenic magnetic particles into sedimentary assemblages is a current challenge in palaeomagnetism. It has been demonstrated recently that magnetic particles produced through biologically controlled mineralization processes, such as magnetosomes from magnetotactic bacteria, contribute to the recording of natural remanent magnetization in marine and lacustrian sediments. Contributions from other, biologically induced, mineralization types, which are known from multiple laboratory experiments to include magnetic minerals, remain largely unknown. Here, we report magnetic properties of iron minerals formed by a community of iron- and manganese-reducing bacteria isolated from a natural groundwater deposit during a 2 yr long incubation experiment. The main iron phases of the biomineralized mass are lepidocrocite, goethite and magnetite, each of which has environmental significance. Unlike the majority of the previous studies that reported superparamagnetic grain size, and thus no remanence carrying capacity of biologically induced magnetite, hysteresis and first-order reversal curves measurements in our study have not detected significant superparamagnetic contribution. The biomineralized mass, instead, contains a mixture of single-domain to pseudo-single-domain and multidomain magnetite particles that are capable of carrying a stable chemical remanent magnetization. Isothermal remanent magnetization acquisition parameters and first-order reversal curves signatures of the biomineralized samples deviate from previously proposed criteria for the distinction of extracellular (biologically induced) magnetic particles in mixtures. Given its potential significance as a carrier of natural remanent magnetization, environmental requirements, distribution in nature and the efficiency in the geomagnetic field recording by biologically induced mineralization need comprehensive investigation.

  7. Magnetic properties of iron minerals produced by natural iron- and manganese-reducing groundwater bacteria

    NASA Astrophysics Data System (ADS)

    Abrajevitch, Alexandra; Kondratyeva, Lubov M.; Golubeva, Evgeniya M.; Kodama, Kazuto; Hori, Rie S.

    2016-06-01

    Understanding the contribution of biogenic magnetic particles into sedimentary assemblages is a current challenge in paleomagnetism. It has been demonstrated recently that magnetic particles produced through biologically controlled mineralization processes, such as magnetosomes from magnetotactic bacteria, contribute to the recording of natural remanent magnetization in marine and lacustrian sediments. Contributions from other, biologically induced, mineralization types, which are known from multiple laboratory experiments to include magnetic minerals, remain largely unknown. Here, we report magnetic properties of iron minerals formed by a community of iron- and manganese-reducing bacteria isolated from a natural groundwater deposit during a two year long incubation experiment. The main iron phases of the biomineralized mass are lepidocrocite, goethite and magnetite, each of which has environmental significance. Unlike the majority of the previous studies that reported superparamagnetic grain size, and thus no remanence carrying capacity of biologically induced magnetite, hysteresis and first order reversal curves measurements in our study have not detected significant superparamagnetic contribution. The biomineralized mass, instead, contains a mixture of single-domain to pseudo-single-domain and multi-domain magnetite particles that are capable of carrying a stable chemical remanent magnetization. Isothermal remanent magnetization acquisition parameters and first order reversal curves signatures of the biomineralized samples deviate from previously proposed criteria for the distinction of extracellular (biologically induced) magnetic particles in mixtures. Given its potential significance as a carrier of natural remanent magnetization, environmental requirements, distribution in nature and the efficiency in the geomagnetic field recording by biologically induced mineralization need comprehensive investigation.

  8. Anaerobic bacteria

    MedlinePlus

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's ...

  9. Mapping of natural and man-made groundwater mineralization by helicopter-borne electromagnetics (Invited)

    NASA Astrophysics Data System (ADS)

    Steuer, A.; Siemon, B.; Meyer, U.

    2010-12-01

    Helicopter-borne electromagnetics (HEM) is an important tool for hydrogeological questions. HEM investigations enable the differentiation of sandy and clayey sediments as well as saltwater and freshwater saturated sediments down to about 150 meters depth. The frequency-domain HEM system operated at the Federal Institute for Geosciences and Natural Resources (BGR) is the RESOLVE system manufactured by Fugro Airborne Surveys. In 2008 and 2009, BGR conducted airborne geophysical measurements for saltwater-freshwater investigation at several survey areas at the German North Sea coast. The surveys were carried out in cooperation with the Leibniz Institute for Applied Geosciences (LIAG) in frame of the project D-AERO. One of these survey areas covers the estuary of the Elbe river to the north-west of the city of Hamburg. Parts of the results of this survey are involved in the project KLIMZUG-NORD, where the Technical University Hamburg-Harburg investigates the environmental effects of the climate change on the estuary of the Elbe river. The HEM measurements reveal both the course of the Geest ridge (high-lying hinterland consisting of pleistocenic moraine sediments) and the swamp belt due to their elevated resistivities, whereas the Marsch land (plain holocenic wet land, alluvium) occurred more conductive. Here, an electrical conductivity anomaly was detected witch could neither be related with seawater intrusion nor with anthropogenic sources. The significant low-resistivity zone of about three square kilometers was identified as a saltwater-rising zone by water analyses of surface water and is an example for natural groundwater mineralization. A man-made groundwater mineralization was investigated by HEM in the Werra river valley in central Germany. About 1000 million cubic meters saline waste water from potash mining have been stored in a karstic limestone and dolomite bed to reduce the amount of saline water emissions directly into the river. BGR conducted surveys in

  10. Combining natural background levels (NBLs) assessment with indicator kriging analysis to improve groundwater quality data interpretation and management.

    PubMed

    Ducci, Daniela; de Melo, M Teresa Condesso; Preziosi, Elisabetta; Sellerino, Mariangela; Parrone, Daniele; Ribeiro, Luis

    2016-11-01

    The natural background level (NBL) concept is revisited and combined with indicator kriging method to analyze the spatial distribution of groundwater quality within a groundwater body (GWB). The aim is to provide a methodology to easily identify areas with the same probability of exceeding a given threshold (which may be a groundwater quality criteria, standards, or recommended limits for selected properties and constituents). Three case studies with different hydrogeological settings and located in two countries (Portugal and Italy) are used to derive NBL using the preselection method and validate the proposed methodology illustrating its main advantages over conventional statistical water quality analysis. Indicator kriging analysis was used to create probability maps of the three potential groundwater contaminants. The results clearly indicate the areas within a groundwater body that are potentially contaminated because the concentrations exceed the drinking water standards or even the local NBL, and cannot be justified by geogenic origin. The combined methodology developed facilitates the management of groundwater quality because it allows for the spatial interpretation of NBL values. PMID:27371772

  11. Quantification of Natural Attenuation of N-S-O Heteroaromatic Compounds in Groundwater at Field Scale

    NASA Astrophysics Data System (ADS)

    Ptak, T.; Piepenbrink, M.; Grathwohl, P.

    2005-12-01

    N-S-O heteroaromatic compounds (HET) can typically be found in groundwater at tar oil contaminated sites. Despite the fact that most of these substances are toxic and potentially carcinogenic, they are not yet routinely monitored. Goal of this contribution is to present results from the investigation of the in-situ natural attenuation potential of HET in groundwater at field-scale. The research has been performed at the `Testfeld-Sed' (TFS) experimental site, a former gasworks site in southern Germany. At the TFS site, the ongoing quantitative determination of the natural attenuation potential of HET is performed using an integral investigation approach at multiple control planes (integral pumping tests, based on the inversion of concentration time series measured during pumping), which are positioned at different distances downgradient of the source zone. Natural attenuation processes result in a reduction of the total contaminant mass flow with increasing transport distance. Degradation rates can be obtained from (multi-)process-based reactive transport modeling which considers all processes contributing to mass flow reduction. Two control planes (CPs) at a distance of about 150 m were used for the integral measurements at the TFS site. The concentration time series already indicate that contaminants like BTEX and PAH almost vanished on their way from the upstream to the downstream CP, while HET were still present. The determined mass flow rates further indicate that some of the HET (especially Methylbenzofurane and Dimethylbenzofurane) are not only very mobile, but also highly persistent. This confirms the dominating role of HET as major contaminants at the TFS site. However, the observed decrease in the total Dimethylbenzofurane mass flow rates already indicates good chances for enhanced natural attenuation (ENA) measures (e.g. injection of H2O2 as additional electron acceptor to stimulate biodegradation) which are planned as next steps. Acknowledgement: The

  12. Does phosphate enhance the natural attenuation of crude oil in groundwater under defined redox conditions?

    PubMed

    Ponsin, Violaine; Mouloubou, Olsen Raïnness; Prudent, Pascale; Höhener, Patrick

    2014-11-15

    After a crude oil spill caused by a broken pipeline in 2009 to a gravel aquifer in southern France, degradation processes under various redox conditions progressively established, but at rates that predict a long life-time of the source under natural attenuation after partial source removal. In this study, we aimed at identifying the rate-limiting factors for each redox condition, with special emphasis on phosphate as limiting nutrient. The study was conducted in laboratory microcosms assembled with material collected on site: sediments, water from monitoring wells, oil and microbial sludge. Redox conditions were promoted by adding electron acceptors (either oxygen, nitrate, limonite (FeO(OH)), cryptomelane (K(Mn(4+),Mn(2+))8O16), or sulfate). For each condition, the role of phosphate was studied by repeated additions for up to 290days. The results showed a very strong stimulation of aerobic and denitrifying rates of oil degradation by phosphate, provided that oxygen and nitrate were repeatedly supplied. Phosphate caused also a marked stimulation of methanogenic degradation, and a relatively small stimulation of metal reduction. These anaerobic processes started only after marked lag phases, and phosphate shortened the lag phase for methanogenic degradation. Degradation of aromatic and aliphatic hydrocarbons with less than 8 carbons, including benzene, was confirmed even under unstimulated conditions. It is concluded that degradation rates at the site are limited by both, availability of electron acceptors and availability of phosphate needed for promoting microbial growth. PMID:24795042

  13. Does phosphate enhance the natural attenuation of crude oil in groundwater under defined redox conditions?

    NASA Astrophysics Data System (ADS)

    Ponsin, Violaine; Mouloubou, Olsen Raïnness; Prudent, Pascale; Höhener, Patrick

    2014-11-01

    After a crude oil spill caused by a broken pipeline in 2009 to a gravel aquifer in southern France, degradation processes under various redox conditions progressively established, but at rates that predict a long life-time of the source under natural attenuation after partial source removal. In this study, we aimed at identifying the rate-limiting factors for each redox condition, with special emphasis on phosphate as limiting nutrient. The study was conducted in laboratory microcosms assembled with material collected on site: sediments, water from monitoring wells, oil and microbial sludge. Redox conditions were promoted by adding electron acceptors (either oxygen, nitrate, limonite (FeO(OH)), cryptomelane (K(Mn4 +,Mn2 +)8O16), or sulfate). For each condition, the role of phosphate was studied by repeated additions for up to 290 days. The results showed a very strong stimulation of aerobic and denitrifying rates of oil degradation by phosphate, provided that oxygen and nitrate were repeatedly supplied. Phosphate caused also a marked stimulation of methanogenic degradation, and a relatively small stimulation of metal reduction. These anaerobic processes started only after marked lag phases, and phosphate shortened the lag phase for methanogenic degradation. Degradation of aromatic and aliphatic hydrocarbons with less than 8 carbons, including benzene, was confirmed even under unstimulated conditions. It is concluded that degradation rates at the site are limited by both, availability of electron acceptors and availability of phosphate needed for promoting microbial growth.

  14. Arsenate and Arsenite Sorption on Magnetite: Relations to Groundwater Arsenic Treatment Using Zerovalent Iron and Natural Attenuation

    EPA Science Inventory

    Magnetite (Fe3O4) is a zerovalent iron corrosion product; it is also formed in natural soil and sediment. Sorption of arsenate (As(V)) and arsenite (As(III)) on magnetite is an important process of arsenic removal from groundwater using zerovalent iron-based permeable reactive ba...

  15. Antimicrobials therapy of anaerobic infections.

    PubMed

    Brook, Itzhak

    2016-06-01

    Anaerobes predominant in the normal human skin and mucous membranes bacterial flora are often a cause of endogenous infections. Anaerobic bacteria are difficult to isolate from infectious sites, and are often overlooked. Anaerobic infections caused by anaerobes can occur in all body sites, including the central nervous system (CNS), oral cavity, head and neck, chest, abdomen, pelvis, skin and soft tissues. The treatment of these infections is complicated by the slow growth of these organisms, their polymicrobial nature and the growing resistance of anaerobes to antimicrobials agents. Antimicrobials are frequently the only form of therapy needed, but in others, they are an important adjunct to surgical drainage and correction of pathology. Because anaerobes are often recovered with aerobic and facultative bacteria, the chosen antimicrobials should cover all pathogens. The antimicrobials effective against anaerobic organisms are metronidazole, carbapenems, combinations of a beta-lactam and a beta-lactamase inhibitor, chloramphenicol, tigecycline and clindamycin. PMID:26365224

  16. Evaluation of occurrence and distribution of natural radionuclides in groundwater of Korea

    NASA Astrophysics Data System (ADS)

    Yun, S. W.; Lee, J. Y.; Park, Y. C.

    2015-12-01

    This study was conducted to evaluate the occurrence and distribution of natural radionuclides in groundwater of Korea. For this purpose, we collected the groundwater radionuclides data of 2000-2011 from National Institute of Environmental Research and available literatures. The sample data were classified into five groups according to the rock types and radionuclide levels were used to construct detailed concentration maps. Radon, uranium, gross-α and radium concentrations ranged from 0.4 to 64,688 pCi/L (mean: 4,907 pCi/L), 0 to 2,297 µg/L (mean: 27.5 µg/L), 0 to 312.0 (mean: 3.9 pCi/L) and 0 to 17.4 pCi/L (mean: 0.2 pCi/L), respectively. Radon concentrations in 562 (53.5%) of 1,501 wells exceeded 4,000 pCi/L, which is the maximum contaminant level by the US environmental protection agency. Uranium, gross-α, and radium concentrations in 121 (11.9%) of 1,031 wells, 34 (3.5%) of 978 wells and 4 (4.5%) of 89 wells exceeded 30 µg/L, 15 pCi/L and 5 pCi/L, respectively. Radionuclide mean concentration in igneous and metamorphic rocks showed higher levels than those of other rocks such as volcanic, carbonate and sedimentary rocks. However, we found that correlations among radionuclides were weak or not significant. This subject is supported by Korea Ministry of Environment as "the GAIA project".

  17. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    SciTech Connect

    Pickering, D.A.; Laase, A.D.; Locke, D.A.

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy`s Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  18. Potential effect of natural gas wells on alluvial groundwater contamination at the Kansas City Plant

    SciTech Connect

    Pickering, D.A.; Laase, A.D. ); Locke, D.A. )

    1993-05-01

    This report is the result of a request for further information about several abandoned natural gas wells at the US Department of Energy's Kansas City Plant (KCP). The request was prompted by an old map showing several, possibly eight, natural gas wells located under or near what is now the southeast corner of the Main Manufacturing Building at KCP. Volatile organic compound contamination in the alluvial aquifer surrounding the gas wells might possibly contaminate the bedrock aquifer if the gas wells still exist as conduits. Several circumstances exist that make it doubtful that contamination is entering the bedrock aquifers: (1) because regional groundwater flow in the bedrock beneath the KCP is expected to be vertically upward, contaminants found in the alluvial aquifer should not migrate down the old wells; (2) because of the low hydraulic conductivity of the bedrock units, contaminant transport would be extremely slow if the contaminants were migrating down the wells; and (3) casing, apparently set through the alluvium in all of the wells, would have deteriorated and may have collapsed; if the casing collapsed, the silty clays in the alluvium would also collapse and seal the well. No definitive information has been discovered about the exact location of the wells. No further search for or consideration of the old gas wells is recommended.

  19. Groundwater, Radon Continuous Monitoring System (α-scintillation Counting) for Natural Hazard Surveillance

    NASA Astrophysics Data System (ADS)

    Galli, G.; Mancini, C.; Quattrocchi, F.

    A ``quasi continuous mode'' monitoring system to measure the radon concentration within a natural environment (mainly groundwater), was designed, assembled and tested, under collaboration between DINCE and ING, partly within the framework of two EC funded programs.The radon monitor consists of a customised discrete automatic sampler which produces a gas flux circuit, and an economical α-scintillation cell, coupled with a reliable electronics-photomultiplier assemblage. A convenient calibration system together with a temporised control system have been set up. The overall ``mean efficiency'' of the system was calculated to be 7.79+/-0.13 counts per minute (cpm) for each Bq/L.Taking into consideration the present and future requirements of a geochemical surveillance network to assess natural hazards, the prototype design evolved from the study of existing systems devoted to monitor radon concentration levels, which are critically reviewed within this paper.In response to the main prerequisite of a remote station: maximum remote sensor versatility preserving shared software and hardware for the network as a whole, this radon monitoring system was conceived as part of a multi-parametric Geochemical Monitoring System (GMS II) prototype, designed and realised as a test-stand for sensors (chemical, hydrological, geophysical, organic chemistry devoted, etc.) in continuous evolution throughout the international market.

  20. Natural background levels and threshold values for groundwater in fluvial Pleistocene and Tertiary marine aquifers in Flanders, Belgium

    NASA Astrophysics Data System (ADS)

    Coetsiers, Marleen; Blaser, Petra; Martens, Kristine; Walraevens, Kristine

    2009-05-01

    Aquifers from the same typology can have strongly different groundwater chemistry. Deducing the groundwater quality of less well-characterized aquifers from well-documented aquifers belonging to the same typology should be done with great reserve, and can only be considered as a preliminary approach. In the EU’s 6th FP BRIDGE project “Background cRiteria for the IDentification of Groundwater thrEsholds”, a methodology for the derivation of threshold values (TV) for groundwater bodies is proposed. This methodology is tested on four aquifers in Flanders of the sand and gravel typology. The methodology works well for all but the Ledo-Paniselian aquifer, where the subdivision into a fresh and saline part is disproved, as a gradual natural transition from fresh to saline conditions in the aquifer is observed. The 90 percentile is proposed as natural background level (NBL) for the unconfined Pleistocene deposits, ascribing the outliers to possible influence of pollution. For the Tertiary aquifers, high values for different parameters have a natural origin and the 97.7 percentile is preferred as NBL. The methodology leads to high TVs for parameters presenting low NBL, when compared to the standard used as a reference. This would allow for substantial anthropogenic inputs of these parameters.

  1. Comparison of Groundwater Recharge under Irrigated Cropland versus Natural Land in Clayey Soils under Mediterranean Climate in Israel

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Scanlon, B. R.

    2010-12-01

    Land use change from natural ecosystems to cropland influences groundwater recharge, including water quantity and quality. Soil core samples (0-11 m depth) from 6 boreholes beneath irrigated cropland (field crops) and 2 boreholes beneath natural ecosystems, in clayey soils undelain by sands, were analyzed for grain-size distribution, water content, and water-extractable Cl. Chloride mass balance and numerical 1D unsaturated zone flow and transport modeling were used for assessing average and transient recharge fluxes, and for testing matrix versus preferential flow hypotheses. Water contents under irrigated cropland are significantly higher than those found under natural land with similar grain-size distribution. Pore water Cl concentrations in deep unsaturated zone under irrigated cropland (900-2000 mg/L) are similar to recent local groundwater Cl and significantly lower than pore water Cl in deep unsaturated zone under natural ecosystems (3000 and 6000 mg/L, Figure 1). Calibrated models’ recharge rates through the soil matrix are much higher under irrigated cropland (90-230 mm/yr) than under natural ecosystems (0-2 mm/yr) and are consistent with groundwater balance estimates of average recharge (110-160 mm/yr). In contrast, matrix-recharge rates under natural ecosystems are much lower than those based on groundwater balance (50-80 mm/yr). While matrix flow in the unsaturated zone under irrigated cropland explains both groundwater and unsaturated zone observations, under natural land, preferential flow paths are needed for supporting unsaturated zone observations and pre-extensive-cultivation groundwater Cl concentrations. Plowing and irrigation prevent development of crack networks and promote matrix percolation through the clay, which flushes salts from previously immobile unsaturated zone pore-water. After flushing is completed, water recharge fluxes are correlated to precipitation of the recent and previous year, while the salinity of recharging water

  2. Impact of anthropogenic and natural processes on the evolution of groundwater chemistry in a rapidly urbanized coastal area, South China.

    PubMed

    Huang, Guanxing; Sun, Jichao; Zhang, Ying; Chen, Zongyu; Liu, Fan

    2013-10-01

    The moving of manufacturing industry from developed countries to Dongguan, China, promoted the semi-urbanization and rural industrialization in this area. It is urgent to acquire the impact of the enhanced anthropogenic pressure on the evolution of groundwater chemistry in this area. The objectives, in this study, were to understand the evolution of groundwater chemistry in Dongguan area based on the comparison of hydrochemical data variations and land use changes during the urbanization, to distinguish the impact of natural processes and anthropogenic activities on the groundwater chemistry by using principal components analysis (PCA) and hierarchical cluster analysis (HCA), and to discuss the origins of trace elements in groundwater. Eighteen physico-chemical parameters were investigated at 73 groundwater sites during July 2006. By analyzing the hydrochemical data, it shows that lateral flow from rivers and agricultural irrigation are the mechanisms controlling the groundwater chemistry in the river network area where the cation exchange of Na(+) in sediments taken up by the exchanger Ca(2+) occurs. Seawater intrusion is the mechanism controlling the groundwater chemistry in the coast area where the cation exchange of Ca(2+) in sediments taken up by the exchanger Na(+) occurs. The ion exchange reaction for fissured aquifer is weak in the study area. In addition, the comparison of hydrochemical data between in 2006 and in 1980 shows that anthropogenic activities such as excessive application of agricultural fertilizers, inappropriate emissions of domestic sewage and excessive emissions of SO2 are responsible for the occurrences of groundwater with NO3(-), SO4(2-) and Mg(2+) types. Four principal components (PCs) were extracted from PCA, which explain 80.86% of the total parameters in water chemistry: PC1, the seawater intrusion and As contamination; PC2, the water-rock interaction, surface water recharge and acidic precipitation; PC3, heavy metal pollution from

  3. Groundwater level response in U.S. Principal Aquifers to natural climate variability on interannual to multidecadal timescales

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Gurdak, J. J.; Dickinson, J.; Hanson, R. T.; Ferré, T. P. A.; Maurer, E. P.

    2014-12-01

    Natural climate variability on interannual to multidecadal timescales are important controls on precipitation, drought, evapotranspiration, streamflow, and groundwater recharge. Climate variability can also augment or diminish human stresses on water resources. Thus, understanding climate variability has particular relevance for groundwater management. Findings will be presented from a national scale study of groundwater level response to natural climate variability in principal aquifers (PAs) of the U.S., including the California Coastal Basin, Rio Grande, Coastal Lowlands, Mississippi Embayment, Floridan, and Glacial aquifer systems. We use the U.S. Geological Survey hydroclimatic analysis toolkit HydroClimATe to perform singular spectrum analysis and identify quasi-periodic signals in precipitation and groundwater time series that are coincident with the Arctic Oscillation (AO) (6-12 mo cycle), Pacific/North American oscillation (PNA) (<1-4 yr cycle), El Niño/Southern Oscillation (ENSO) (2-7 yr cycle), North Atlantic Oscillation (NAO) (3-6 yr cycle), Pacific Decadal Oscillation (PDO) (15-30 yr cycle), and Atlantic Multidecadal Oscillation (AMO) (50-70 yr cycle). Nearly all of the quasi-periodic signals in the precipitation and groundwater levels have a statistically significant lag correlation (95% confidence interval) with the AO, PNA, ENSO, NAO, PDO, and AMO indices. The largest amount of variance in precipitation and groundwater levels was attributed to the PDO, accounting for more than 90% of the variance in many PAs. The next largest amount of variance in precipitation and groundwater levels was attributed to ENSO, accounting for more than 50% of the variance in many PAs. The AMO was the least frequently detected signal in all time series but accounted for as much as 95% of the variance when detected. Thus, climate variability on interannual to multidecadal timescales has a statistically significant and measurable effect on the lagged responses of

  4. Beneficial effects of natural Jeju groundwaters on lipid metabolism in high-fat diet-induced hyperlipidemic rats

    PubMed Central

    Wang, Yan-chao; Lu, Jin-miao; Jin, Hui-zi; Ma, Ai-niu; Zhang, Jin-yang; Gong, Nian; Xiao, Qi; Zhu, Bin; Lv, Ying-fang; Yu, Na; Zhang, Wei-dong

    2014-01-01

    BACKGROUND Groundwater is believed to possess many beneficial effects due to its natural source of various minerals. In this study, we examined the effects of natural Jeju groundwater S1 (Samdasoo™), S2 and S3 pumped up from different locations of Jeju Island, Korea, along with local tap water, on body weight gain, serum lipids and lipoproteins, and liver histopathology in high-fat diet-induced hyperlipidemic rats. MATERIALS/METHODS Rats were randomly and equally divided into 6 groups. Different water samples were supplied to the hyperlipidemic rats as their daily drinking water and the widely-used anti-hyperlipidemic drug simvastatin was used as a positive control. Body weight, serum lipids and lipoproteins were measured weekly. Liver weight, liver index and liver histopathology were examined after the execution of the rats. RESULTS After drinking Jeju groundwaters for two months, S2 but not S3 significantly reduced weight growth and serum triglycerides levels and increased high density lipoprotein-C (HDL-C) without affecting total cholesterol or LDL-C. S1 and particularly S2 significantly reduced the severity of liver hypertrophy and steatosis. All Groundwaters had much higher contents of vanadium (S3>S2>S1>>tap water) whereas S1 and S2 but not S3 markedly blocked autoxidation of ferrous ions. CONCLUSION Jeju Groundwater S1 and particularly S2 exhibit protective effects against hyperlipidemia and fatty liver and hypothesize that the beneficial effect of Jeju Groundwaters may be contributed from blockade of autoxidation of ferrous ions rather than their high contents of vanadium. PMID:24741400

  5. A Method for Catchment Scale Mapping of Groundwater-Dependent Ecosystems to Support Natural Resource Management (Queensland, Australia).

    PubMed

    Glanville, K; Ryan, T; Tomlinson, M; Muriuki, G; Ronan, M; Pollett, A

    2016-02-01

    Immediate and foreseeable threats to groundwater-dependent ecosystems (GDEs) are widely acknowledged, many linked to altered groundwater regimes including changes in groundwater flow, flux, pressure, level and/or quality (Eamus et al. in Aust J Bot 54:97-114, 2006a). Natural resource managers and other decision-makers often lack sufficient information at an appropriate scale to understand the groundwater dependency of ecosystems and ensure that GDEs are adequately considered in decision-making processes. This paper describes a new catchment scale mapping method for GDEs based on the integration of local expert knowledge with detailed spatial datasets to delineate GDEs at a scale compatible with management and planning activities. This overcomes one of the key criticisms often levelled at broader scale mapping methods-that information from local and regional experts, with significant understanding of landscape processes and ecosystems, is not incorporated into the datasets used by decision-makers. Expert knowledge is conveyed in the form of pictorial conceptual models representing the components, processes and interrelationships of groundwater within a catchment and the ecosystems dependent on it. Each mapped GDE is linked to a pictorial conceptual model and a mapping rule-set to provide decision-makers with valuable information about where, how and why GDEs exist in a landscape. PMID:26404433

  6. A Method for Catchment Scale Mapping of Groundwater-Dependent Ecosystems to Support Natural Resource Management (Queensland, Australia)

    NASA Astrophysics Data System (ADS)

    Glanville, K.; Ryan, T.; Tomlinson, M.; Muriuki, G.; Ronan, M.; Pollett, A.

    2016-02-01

    Immediate and foreseeable threats to groundwater-dependent ecosystems (GDEs) are widely acknowledged, many linked to altered groundwater regimes including changes in groundwater flow, flux, pressure, level and/or quality (Eamus et al. in Aust J Bot 54:97-114, 2006a). Natural resource managers and other decision-makers often lack sufficient information at an appropriate scale to understand the groundwater dependency of ecosystems and ensure that GDEs are adequately considered in decision-making processes. This paper describes a new catchment scale mapping method for GDEs based on the integration of local expert knowledge with detailed spatial datasets to delineate GDEs at a scale compatible with management and planning activities. This overcomes one of the key criticisms often levelled at broader scale mapping methods—that information from local and regional experts, with significant understanding of landscape processes and ecosystems, is not incorporated into the datasets used by decision-makers. Expert knowledge is conveyed in the form of pictorial conceptual models representing the components, processes and interrelationships of groundwater within a catchment and the ecosystems dependent on it. Each mapped GDE is linked to a pictorial conceptual model and a mapping rule-set to provide decision-makers with valuable information about where, how and why GDEs exist in a landscape.

  7. SITE CHARACTERIZATION OF AREA 6, DOVER AIR FORCE BASE, IN SUPPORT OF NATURAL ATTENUATION AND ENHANCED ANAEROBIC BIOREMEDIATION PROJECTS

    EPA Science Inventory

    A field program for site characterization of targeted study areas at the Dover Air Force Base was conducted between January 16, 1995, and March 9, 1995. The stated objectives of the investigation, "to characterize the stratigraphy, depth to groundwater, groundwater flow directio...

  8. Anaerobic Thermophiles

    PubMed Central

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has

  9. Anaerobic thermophiles.

    PubMed

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term "extremophile" was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of "extreme" environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally "hot environments" on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely

  10. Regional hydrogeochemical groundwater characterization and Natural Arsenic occurrence in Upper Valtellina Valley (Central Italian Alps, Italy)

    NASA Astrophysics Data System (ADS)

    Pena Reyes, Fredy; Crosta, Giovanni B.; Frattini, Paolo; Basiricò, Stefano

    2015-04-01

    The aim of the research is the characterization of the alpine Upper Valtellina Valley (central Italian Alps, 800 km2) aquifers by means of hydrogeological, hydrogeochemical, As speciation, isotopic and whole-rock analyses. In particular, the main focus of the study was the understanding of the processes responsible for As release and mobilization into the groundwater. Historical chemical data from springs, wells, lakes, rivers and public fountains were collected from the Lombardy Region Health Agency (ASL) and implemented into a geodatabase. The available groundwater chemistry analyses (3050) from five municipalities (Bormio, Livigno, Valdidentro, Valdisotto and Valfurva) cover a relatively long time span between 1996 and 2011. Moreover, samples across the entire study area and covering one full hydrologic year 2012-2013 were collected during four different campaigns (June 2012, October 2012, May 2013, and September 2013) and analyzed . During these campaigns, water samples have been collected from both cold springs and thermal springs. The hydrogeochemistry of aquifers and superficial waters through the hydrologic year, and the long-term regional As distribution and time variability were analyzed. Although the studied springs belong to different catchments with different hydrochemical and lithological conditions, they present some typical characteristics: (1) the water types are dominated by dissolution of the main ions Ca - Mg and SO4-HCO3; (2) the Cl concentration is always very low, and poorly correlated with other ions; (3) the circulation time obtained from isotopic data ranges between 5 and 10 years for thermal springs and it is lower than 2 years for cold springs; (4) the average yearly temperatures (about 12°C for cold springs, and between 18°C and 42° for thermal springs) are nearly constant through the year; (5) dominant oxidizing environments have been observed for most of the cold springs and also for the thermal springs; (6) anthropogenic

  11. Sorption of americium in tuff and pure minerals using synthetic and natural groundwaters

    SciTech Connect

    Triay, I.R.; Meijer, A.; Cisneros, M.R.; Miller, G.G.; Mitchell, A.J.; Ott, M.A.; Hobart, D.E.; Palmer, P.D.; Perrin, R.E.; Aguilar, R.D.

    1989-12-01

    The distribution of Am between selected solid and liquid phases has been studied using initial {sup 241}Am solutions with a molarity smaller than 1 {times} 10{sup {minus}11}. The synthetic and natural groundwaters used have pH values in the 7--8 range and a total alkalinity of approximately 1 mN which is mainly due to bicarbonate. Mass spectrometric isotope dilution was utilized to determine the amount of Am in the solution phase initially and after equilibrium was attained. Using this sensitive technique, 7 {times} 10{sup 8} atoms of {sup 241}Am were accurately measured. Our results indicate that the percent of Am lost to the walls of the container in the absence of geologic material varies from 35 to 84. The Am sorption coefficient determined is on the order of 10{sup 3} ml/g for clinoptilolite, 10{sup 4} ml/g for tuff consisting mainly of alkali feldspar and cristobalite, and 10{sup 5} ml/g for romanechite. 12 refs.

  12. Experimental studies in natural groundwater-recharge dynamics: The analysis of observed recharge events

    USGS Publications Warehouse

    Sophocleous, M.; Perry, C.A.

    1985-01-01

    The amounts and time distribution of groundwater recharge from precipitation over an approximately 19-month period were investigated at two instrumented sites in south-central Kansas. Precipitation and evapotranspiration sequences, soil-moisture profiles and storage changes, water fluxes in the unsaturated zone and hydraulic gradients in the saturated zone at various depths, soil temperatures, water-table hydrographs, and water-level changes in nearby wells clearly depict the recharge process. Antecedent moisture conditions and the thickness and nature of the unsaturated zone were found to be the major factors affecting recharge. Although the two instrumented sites are located in sand-dune environments in areas characterized by shallow water table and subhumid continental climate, a significant difference was observed in the estimated effective recharge. The estimates ranged from less than 2.5 to approximately 154 mm at the two sites from February to June 1983. The main reasons for this large difference in recharge estimates were the greater thickness of the unsaturated zone and the lower moisture content in that zone resulting from lower precipitation and higher potential evapotranspiration for one of the sites. Effective recharge took place only during late winter and spring. No summer or fall recharge was observed at either site during the observation period of this study. ?? 1985.

  13. Experimental studies in natural groundwater recharge dynamics: Assessment of recent advances in instrumentation

    USGS Publications Warehouse

    Sophocleous, M.; Perry, C.A.

    1984-01-01

    To quantify and model the natural groundwater-recharge process, two sites in south-central Kansas, U.S.A., were instrumented with various modern sensors and data microloggers. The atmospheric-boundary layer and the unsaturated and saturated soil zones were monitored as a unified regime. Data from the various sensors were collected using microloggers in combination with magnetic-cassette tape, graphical and digital recorders, analog paper-tape recorders, and direct observations to evaluate and automate data collection and processing. Atmospheric sensors included an anemometer, a tipping-bucket raingage, an air-temperature thermistor, a relative-humidity probe, a net radiometer, and a barometric-pressure transducer. Sensors in the unsaturated zone consisted of soil-temperature thermocouples, tensiometers coupled with pressure transducers and dial gages, gypsum blocks, and a neutron moisture probe operated by an observer. The saturated-zone sensors consisted of a water-level pressure transducer, a conventional float gage connected to a variable potentiometer, soil thermocouples, and a number of multiple-depth piezometers. Evaluation of the operation of these sensors and recorders indicated that certain types of equipment such as pressure transducers are very sensitive to environmental conditions. Extraordinary steps had to be taken to protect some of the equipment, whereas other equipment seemed to be reliable under all conditions. Based on such experiences, a number of suggestions aimed at improving such investigations are outlined. ?? 1984.

  14. Dynamics of natural prokaryotes, viruses, and heterotrophic nanoflagellates in alpine karstic groundwater.

    PubMed

    Wilhartitz, Inés C; Kirschner, Alexander K T; Brussaard, Corina P D; Fischer, Ulrike R; Wieltschnig, Claudia; Stadler, Hermann; Farnleitner, Andreas H

    2013-08-01

    Seasonal dynamics of naturally occurring prokaryotes, viruses, and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. To our knowledge, this study is the first to shed light on the occurrence and possible interrelationships between these three groups in karstic groundwater. Hydrological and microbiological standard indicators were recovered simultaneously in order to estimate surface influence, especially during rainfall events. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. Prokaryotic numbers averaged 5.1 × 10(7) and 1.3 × 10(7) cells L(-1) , and heterotrophic nanoflagellate abundance averaged 1.1 × 10(4) and 3 × 10(3) cells L(-1) in the limestone spring type (LKAS2) and the dolomitic spring type (DKAS1), respectively. Viral abundance in LKAS2 and DKAS1 averaged 9.4 × 10(8) and 1.1 × 10(8) viruses L(-1) . Unlike in DKAS1, the dynamic spring type LKAS2 revealed a clear difference between base flow and high discharge conditions. The virus-to-prokaryotes ratio was generally lower by a factor of 2-3, at higher average water residence times. Furthermore, the high prokaryotes-to-heterotrophic nanoflagellate ratios, namely about 4700 and 5400 for LKAS2 and DKAS1, respectively, pointed toward an uncoupling of these two groups in the planktonic fraction of alpine karstic aquifers. PMID:23828838

  15. Modeling of arsenic adsorption kinetics of synthetic and contaminated groundwater on natural laterite.

    PubMed

    Maiti, Abhijit; Sharma, Himanshu; Basu, Jayanta Kumar; De, Sirshendu

    2009-12-30

    A simple shrinking core model is applied to predict the adsorption kinetics of arsenite and arsenate species onto natural laterite (NL) in a stirred tank adsorber. The proposed model is a two-resistance model, in which two unknown parameters, external mass transfer coefficient (K(f)) and pore diffusion coefficient (D(e)) are estimated by comparing the simulation concentration profile with the experimental data using a nonlinear optimization technique. The model is applied under various operating conditions, e.g., initial arsenic concentration, NL dose, NL particle size, temperature, stirring speed, etc. Estimated values of D(e) and K(f) are found to be in the range of 2.2-2.6 x 10(-11)m(2)/s and 1.0-1.4 x 10(-6)m/s at 305K for different operating conditions, respectively. D(e) and K(f) values are found to be increasing with temperature and stirrer speed, respectively. Calculated values of Biot numbers indicate that both external mass transfer and pore diffusion are important during the adsorption. The model is also applied satisfactorily to predict the arsenic adsorption kinetics of arsenic contaminated groundwater-NL system and can be used to scale up. PMID:19717233

  16. Evolution of a pathway for chlorobenzene metabolism leads to natural attenuation in contaminated groundwater

    PubMed

    van der Meer JR; Werlen; Nishino; Spain

    1998-11-01

    Complete metabolism of chlorinated benzenes is not a feature that is generally found in aerobic bacteria but is thought to be due to a novel recombination of two separate gene clusters. Such a recombination could be responsible for adaptation of a natural microbial community in response to contamination with synthetic chemicals. This hypothesis was tested in a chlorobenzene (CB)-contaminated aquifer. CB-degrading bacteria from a contaminated site were characterized for a number of years by examining a combination of growth characteristics and DNA-DNA hybridization, PCR, and DNA sequence data. The genetic information obtained for the CB pathway of the predominant microorganism, Ralstonia sp. strain JS705, revealed a unique combination of (partially duplicated) genes for chlorocatechol degradation and genes for a benzene-toluene type of aromatic ring dioxygenase. The organism was detected in CB-polluted groundwater by hybridizing colonies cultivated on low-strength heterotrophic media with probes for the CB pathway. Southern hybridizations performed to determine the organization of the CB pathway genes and the 16S ribosomal DNA indicated that CB-degrading organisms isolated from different wells at the site were identical to JS705. Physiological characterization by the Biolog test system revealed some differences. The genes for the aromatic ring dioxygenase and dihydrodiol dehydrogenase of JS705 were detected in toluene and benzene degraders from the same site. Our results suggest that recent horizontal gene transfer and genetic recombination of existing genes between indigenous microorganisms were the mechanisms for evolution of the catabolic pathway. Evolution of the CB pathway seems to have created the capacity for natural attenuation of CB at the contaminated site. PMID:9797264

  17. Hydrogeochemical overview and natural arsenic occurrence in groundwater from alpine springs (upper Valtellina, Northern Italy)

    NASA Astrophysics Data System (ADS)

    Peña Reyes, Fredy Alexander; Crosta, Giovanni B.; Frattini, Paolo; Basiricò, Stefano; Della Pergola, Roberto

    2015-10-01

    High arsenic (As) concentrations (up to 230 μg/L) have been historically observed (since 1999) in the upper Valtellina valley groundwater (UVV, central Italian Alps), and measured in samples collected during four campaigns of one full hydrological year (summer 2012-summer 2013). During these campaigns, water has been collected from both cold springs and thermal springs. The hydrogeochemistry of aquifers and superficial waters through the hydrologic year, and the long-term regional As distribution and time variability were analyzed. Although the studied springs belong to different catchments with different hydrochemical and lithological conditions, they present some typical characteristics: (1) the water types are dominated by Ca-Mg and SO4-HCO3 main ions, with seasonal variations for the second end members; (2) the Cl concentration is always very low, and poorly correlated with other ions; (3) the circulation time obtained from isotopic data ranges between 5 and 10 years for thermal springs and it is lower than 2 years for cold springs; (4) dominant oxidizing conditions have been observed for most of the cold and for the thermal springs; (5) anthropogenic contamination is absent, while natural contamination of arsenic affects most of the springs, with a natural background level for the entire UVV of 33 μg/L; (6) both As (V) and As (III) are present in all the springs analyzed, with a marked prevalence of As (V) among the cold ones. These conditions suggest that the latter belong to recent hydrochemical immature aquifers, where the presence of arsenic is mostly related to alkali desorption and sulfide oxidation, while the thermal springs derive from the rapid uprising of deep-circulation water, with a high concentration of geothermal arsenic.

  18. Dynamics of natural prokaryotes, viruses, and heterotrophic nanoflagellates in alpine karstic groundwater

    PubMed Central

    Wilhartitz, Inés C; Kirschner, Alexander K T; Brussaard, Corina P D; Fischer, Ulrike R; Wieltschnig, Claudia; Stadler, Hermann; Farnleitner, Andreas H

    2013-01-01

    Abstract Seasonal dynamics of naturally occurring prokaryotes, viruses, and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. To our knowledge, this study is the first to shed light on the occurrence and possible interrelationships between these three groups in karstic groundwater. Hydrological and microbiological standard indicators were recovered simultaneously in order to estimate surface influence, especially during rainfall events. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. Prokaryotic numbers averaged 5.1 × 107 and 1.3 × 107 cells L−1, and heterotrophic nanoflagellate abundance averaged 1.1 × 104 and 3 × 103 cells L−1 in the limestone spring type (LKAS2) and the dolomitic spring type (DKAS1), respectively. Viral abundance in LKAS2 and DKAS1 averaged 9.4 × 108 and 1.1 × 108 viruses L−1. Unlike in DKAS1, the dynamic spring type LKAS2 revealed a clear difference between base flow and high discharge conditions. The virus-to-prokaryotes ratio was generally lower by a factor of 2–3, at higher average water residence times. Furthermore, the high prokaryotes-to-heterotrophic nanoflagellate ratios, namely about 4700 and 5400 for LKAS2 and DKAS1, respectively, pointed toward an uncoupling of these two groups in the planktonic fraction of alpine karstic aquifers. Seasonal dynamics of naturally occurring prokaryotes, viruses and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. PMID:23828838

  19. Hydrogeophysical Characterizations of Streambed Sedimentology and Stream-Groundwater Interactions in a Natural Stream

    NASA Astrophysics Data System (ADS)

    Hyun, Y.; Lee, S.; Kim, H.; Lee, K.

    2011-12-01

    than values at 10 cm depth due to, getting to deep, existence of low permeable sediments like loamy sand and silt loam. Depositional features of streambed in a natural stream are predicted to affect both vertical water flux and pattern on surface water-groundwater interaction. This subject is supported by Brain Korea 21 and Korea Ministry of Environment as 'The GAIA Project (173-092-009)'

  20. Waste-to-wheel analysis of anaerobic-digestion-based renewable natural gas pathways with the GREET model.

    SciTech Connect

    Han, J.; Mintz, M.; Wang, M.

    2011-12-14

    In 2009, manure management accounted for 2,356 Gg or 107 billion standard cubic ft of methane (CH{sub 4}) emissions in the United States, equivalent to 0.5% of U.S. natural gas (NG) consumption. Owing to the high global warming potential of methane, capturing and utilizing this methane source could reduce greenhouse gas (GHG) emissions. The extent of that reduction depends on several factors - most notably, how much of this manure-based methane can be captured, how much GHG is produced in the course of converting it to vehicular fuel, and how much GHG was produced by the fossil fuel it might displace. A life-cycle analysis was conducted to quantify these factors and, in so doing, assess the impact of converting methane from animal manure into renewable NG (RNG) and utilizing the gas in vehicles. Several manure-based RNG pathways were characterized in the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model, and their fuel-cycle energy use and GHG emissions were compared to petroleum-based pathways as well as to conventional fossil NG pathways. Results show that despite increased total energy use, both fossil fuel use and GHG emissions decline for most RNG pathways as compared with fossil NG and petroleum. However, GHG emissions for RNG pathways are highly dependent on the specifics of the reference case, as well as on the process energy emissions and methane conversion factors assumed for the RNG pathways. The most critical factors are the share of flared controllable CH{sub 4} and the quantity of CH{sub 4} lost during NG extraction in the reference case, the magnitude of N{sub 2}O lost in the anaerobic digestion (AD) process and in AD residue, and the amount of carbon sequestered in AD residue. In many cases, data for these parameters are limited and uncertain. Therefore, more research is needed to gain a better understanding of the range and magnitude of environmental benefits from converting animal manure to RNG via AD.

  1. Application Of Monitored Natural Attenuation For Cleanup Of Radionuclides In Groundwater

    EPA Science Inventory

    A retrospective analysis was conducted to evaluate the unsuccessful performance of an MNA remedy for uranium contamination in groundwater at a Superfund site in Richland, Washington. The primary factors that limited the accuracy of contaminant transport model projections at this...

  2. Characterizing hydrology and the importance of ground-water discharge in natural and constructed wetlands

    USGS Publications Warehouse

    Hunt, Randall J.; Walker, John F.; Krabbenhoft, David P.

    1999-01-01

    Although considered the most important component for the establishment and persistence of wetlands, hydrology has been hard to characterize and linkages between hydrology and other environmental conditions are often poorly understood. In this work, methods for characterizing a wetland’s hydrology from hydrographs were developed, and the importance of ground water to the physical and geochemical conditions in the root zone was investigated. Detailed sampling of nearly continuous hydrographs showed that sites with greater ground-water discharge had higher water tables and more stable hydrographs. Subsampling of the continuous hydrograph failed to characterize the sites correctly, even though the wetland complex is located in a strong regional ground-water-discharge area. By comparing soil-moisture-potential measurements to the water-table hydrograph at one site, we noted that the amount of root-zone saturation was not necessarily driven by the water-table hydrograph but can be a result of other soil parameters (i.e., soil texture and associated capillary fringe). Ground-water discharge was not a significant determinant of maximum or average temperatures in the root zone. High ground-water discharge was associated with earliest date of thaw and shortest period of time that the root zone was frozen, however. Finally, the direction and magnitude of shallow ground-water flow was found to affect the migration and importance of a geochemical species. Areas of higher ground-water discharge had less downward penetration of CO2 generated in the root zone. In contrast, biotically derived CO2 was able to penetrate the deeper ground-water system in areas of ground-water recharge. Although ground-water flows are difficult to characterize, understanding these components is critical to the success of wetland restoration and creation efforts.

  3. Characterization of hot spots for natural chloroform formation: Relevance for groundwater quality

    NASA Astrophysics Data System (ADS)

    Jacobsen, Ole S.; Albers, Christian N.; Laier, Troels

    2015-04-01

    Chloroform soil hot spot may deteriorate groundwater quality and may even result in chloroform concentration exceeding the Danish maximum limit of 1 µg/L in groundwater for potable use. In order to characterize the soil properties important for the chloroform production, various ecosystems were examined with respect to soil air chloroform and soil organic matter type and content. Coniferous forest areas, responsible for highest chloroform concentrations, were examined on widely different scales from km to cm scale. Furthermore, regular soil gas measurements including chloroform were performed during 4 seasons at various depths, together with various meteorological measurements and soil temperature recordings. Laboratory incubation experiments were also performed on undisturbed soil samples in order to examine the role of various microbiota, fungi and bacteria. To identify hot spots responsible for the natural contamination we have measured the production of chloroform in the upper soil from different terrestrial systems. Field measurements of chloroform in top soil air were used as production indicators. The production was however not evenly distributed at any scale. The ecosystems seem to have quite different net-productions of chloroform from very low in grassland to very high in some coniferous forests. Within the forest ecosystem we found large variation in chloroform concentrations depending on vegetation. In beech forest we found the lowest values, somewhat higher in an open pine forest, but the highest concentrations were detected in spruce forest without any vegetation beneath. Within this ecotype, it appeared that the variation was also large; hot spots with 2-4 decades higher production than the surrounding area. These hot spots were not in any way visually different from the surroundings and were of variable size from 3 to 20 meters in diameter. Besides this, measurements within a seemingly homogenous hot spot showed that there was still high

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

    USGS Publications Warehouse

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

    1996-01-01

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

  5. Natural attenuation processes of arsenic in the groundwater of the Brahmaputra floodplain of Assam, India.

    PubMed

    Sailo, Lalsangzela; Mahanta, Chandan

    2016-01-01

    Natural attenuation of higher arsenic (As) concentration in the groundwater of the Brahmaputra valley of Assam can be a viable option for its remediation. The assessment of attenuation capacities in aquifers was done using three sediment core samples (namely C_50, C_70 and C_150) representing the commonly found sediments and characterized as viz. reduced, oxidized and moderately oxidized sediments, respectively. The feasability of aquifers to release low As water depends on the sorption capacity of the sediments to directly adsorbed as As(III) and/or oxidation to As(V) on oxidative sites. The various batch sorption experiments along with competition of other anions for adsorption sites at different concentrations were investigated. The sediments were observed to adsorb both As(III) and As(V) with varying magnitudes depending on the species of As, pH and concentrations of competing anions. The Elovich kinetic model best described kinetic test data. The oxidized sediment (C_70) with the highest Fe and Mn content has the highest adsorption capacity. The competition for adsorption sites with As(V) in the sediment samples followed the order PO4(3-) > SiO2 > HCO3(-). The oxidation of As(III) to As(V) by the sediments was analyzed as it is also the most effective pathway to reduce the toxicity as well as the mobility of As in the subsurface environment. Sediment C_70 showed the highest potential to oxidize As(III) to As(V) in the oxidative sites of the sediments. The removal of As(III) in the oxidative site via As(V) was the dominant As removal mechanism for the oxidized sediment (C_70) and moderately oxidized sediment (C_150) than the direct adsorption of As(III) on the adsorptive sites as on reduced sediment sample C_50. Therefore, targeting the oxidized sediment with a high concentration of Fe-oxides and Mn-oxides might make natural attenuation of As viable in the study areas. PMID:26647841

  6. Kinetics of scheelite dissolution in groundwater: defining the release rate of tungsten contamination from a natural source

    NASA Astrophysics Data System (ADS)

    Montgomery, S. D.; Mckibben, M. A.

    2011-12-01

    Tungsten, an emerging contaminant, has no EPA standard for its permissible levels in drinking water. At sites in California, Nevada, and Arizona there may be a correlation between elevated levels of tungsten in drinking water and clusters of childhood acute lymphocytic leukemia (ALL). Developing a better understanding of how tungsten is released from rocks into surface and groundwaters is therefore of growing environmental interest. Knowledge of tungstate ore mineral weathering processes, particularly the rates of dissolution of scheelite (CaWO4) in groundwater, could improve models of how tungsten is released and transported in natural waters. Our research is focusing on experimental determination of the rates and products of tungstate mineral dissolution in synthetic groundwater, as a function of temperature, pH and mineral surface area. The initial rate method is being used to develop rate laws. Batch reactor experiments are conducted within constant temperature circulation baths over a pH range of 2-9. Cleaned scheelite powder with grain diameters of 106-150um is placed between two screens in a sample platform and then placed inside a two liter Teflon vessel filled with synthetic groundwater. Ports on the vessel allow sample extraction, temperature and pH measurement, gas inflow, and water circulation. Aliquots of solution are taken periodically for product analysis by ICP -MS. Changes in mineral surface characteristics are monitored using SEM and EDS methods. Results so far reveal that the dissolution of scheelite is incongruent at both neutral and low pH. Solid tungstic acid forms on scheelite mineral surfaces under acidic conditions, implying that this phase controls the dissolution rate in acidic environments. The influence of dissolved CO2 and resultant calcium carbonate precipitation on the dissolution of scheelite at higher pH is also being investigated. The rate law being developed for scheelite dissolution will be useful in reactive-transport computer

  7. Anaerobic digestion of swine manure under natural zeolite addition: VFA evolution, cation variation, and related microbial diversity.

    PubMed

    Lin, Lin; Wan, Chunli; Liu, Xiang; Lei, Zhongfang; Lee, Duu-Jong; Zhang, Yi; Tay, Joo Hwa; Zhang, Zhenya

    2013-12-01

    Batch experiments were carried out on anaerobic digestion of swine manure under 10 % of total solids and 60 g/L of zeolite addition at 35 °C. Four distinctive volatile fatty acid (VFAs) evolution stages were observed during the anaerobic process, i.e., VFA accumulation, acetic acid (HAc) and butyric acid (HBu) utilization, propionic acid (HPr) and valeric acid (HVa) degradation, and VFA depletion. Large decreases in HAc/HBu and HPr/HVa occurred respectively at the first and second biogas peaks. Biogas yield increased by 20 % after zeolite addition, about 356 mL/g VSadded with accelerated soluble chemical oxygen demand degradation and VFA (especially HPr and HBu) consumption in addition to a shortened lag phase between the two biogas peaks. Compared with Ca(2+) and Mg(2+) (100-300 mg/L) released from zeolite, simultaneous K(+) and NH4 (+) (580-600 mg/L) adsorptions onto zeolite particles contributed more to the enhanced biogasification, resulting in alleviated inhibition effects of ammonium on acidogenesis and methanogenesis, respectively. All the identified anaerobes could be grouped into Bacteroidetes and Firmicutes, and zeolite addition had no significant influence on the microbial biodiversity in this study. PMID:24270923

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

    NASA Astrophysics Data System (ADS)

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

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

  9. Discovery of Multiple Modified F430 Coenzymes in Methanogens and Anaerobic Methanotrophic Archaea Suggests Possible New Roles for F430 in Nature

    PubMed Central

    Allen, Kylie D.; Wegener, Gunter

    2014-01-01

    Methane is a potent greenhouse gas that is generated and consumed in anaerobic environments through the energy metabolism of methanogens and anaerobic methanotrophic archaea (ANME), respectively. Coenzyme F430 is essential for methanogenesis, and a structural variant of F430, 172-methylthio-F430 (F430-2), is found in ANME and is presumably essential for the anaerobic oxidation of methane. Here we use liquid chromatography–high-resolution mass spectrometry to identify several new structural variants of F430 in the cell extracts of selected methanogens and ANME. Methanocaldococcus jannaschii and Methanococcus maripaludis contain an F430 variant (denoted F430-3) that has an M+ of 1,009.2781. This mass increase of 103.9913 over that of F430 corresponds to C3H4O2S and is consistent with the addition of a 3-mercaptopropionate moiety bound as a thioether followed by a cyclization. The UV absorbance spectrum of F430-3 was different from that of F430 and instead matched that of an F430 derivative where the 173 keto moiety had been reduced. This is the first report of a modified F430 in methanogens. In a search for F430-2 and F430-3 in other methanogens and ANME, we have identified a total of nine modified F430 structures. One of these compounds may be an abiotic oxidative product of F430, but the others represent naturally modified versions of F430. This work indicates that F430-related molecules have additional functions in nature and will inspire further research to determine the biochemical role(s) of these variants and the pathways involved in their biosynthesis. PMID:25107965

  10. Anaerobic bacteria

    MedlinePlus

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  11. Stable lead isotopes reveal a natural source of high lead concentrations to gasoline-contaminated groundwater

    USGS Publications Warehouse

    Landmeyer, J.E.; Bradley, P.M.; Bullen, T.D.

    2003-01-01

    Concentrations of total lead as high as 1,600 ??g/L were detected in gasoline-contaminated and uncontaminated groundwater at three gasoline-release sites in South Carolina. Total lead concentrations were highest in turbid groundwater samples from gasoline-contaminated and uncontaminated wells, whereas lower turbidity groundwater samples (collected using low-flow methods) had lower total lead concentrations. Dissolved lead concentrations in all wells sampled, however, were less than 15 ??g total lead/L, the current United States Environmental Protection Agency (US EPA) maximum contaminant level (MCL). Because many total lead concentrations exceeded the MCL, the source of lead to the groundwater system at two of the three sites was investigated using a stable lead isotope ratio approach. Plots of the stable isotope ratios of lead (Pb) in groundwater as 207Pb/206Pb versus 208Pb/206Pb, and 208Pb/204Pb versus 206Pb/204Pb were similar to ratios characteristic of lead-based minerals in local rocks of the southeastern US, and were not similar to the stable lead isotopes ratios characteristic of distant lead ore deposits such as Broken Hill, Australia, used to produce tetraethyl lead in gasoline products prior to its phase-out and ban in the United States. Moreover, the isotopic composition of dissolved lead was equivalent to the isotopic composition of total lead in turbid samples collected from the same well, suggesting that the majority of the lead detected in the groundwater samples was associated with sediment particulates of indigenous aquifer material, rather than lead associated with spilled leaded gasoline. The results of this investigation indicate that (1) lead detected at some gasoline-release sites may be derived from the local aquifer material, rather than the gasoline release, and consequently may affect site-specific remediation goals; (2) non-low flow groundwater sampling methods, such as a disposable bailer, may result in turbid groundwater samples and

  12. The role of anthropogenic and natural factors in shaping the geochemical evolution of groundwater in the Subei Lake basin, Ordos energy base, Northwestern China.

    PubMed

    Liu, Fei; Song, Xianfang; Yang, Lihu; Han, Dongmei; Zhang, Yinghua; Ma, Ying; Bu, Hongmei

    2015-12-15

    Groundwater resources are increasingly exploited for industrial and agricultural purposes in many arid regions globally, it is urgent to gain the impact of the enhanced anthropogenic pressure on the groundwater chemistry. The aim of this study was to acquire a comprehensive understanding of the evolution of groundwater chemistry and to identify the impact of natural and anthropogenic factors on the groundwater chemistry in the Subei Lake basin, Northwestern China. A total of 153 groundwater samples were collected and major ions were measured during the three campaigns (August and December 2013, May 2014). At present, the major hydrochemical facies in unconfined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Na-HCO3, Ca-Mg-SO4 and Na-SO4-Cl types, while the main hydrochemical facies in confined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Ca-HCO3 and Na-HCO3 types. Relatively greater seasonal variation can be observed in the chemical constituents of confined groundwater than that of unconfined groundwater. Rock weathering predominates the evolution of groundwater chemistry in conjunction with the cation exchange, and the dissolution/precipitation of gypsum, halite, feldspar, calcite and dolomite are responsible for the chemical constituents of groundwater. Anthropogenic activities can be classified as: (1) groundwater overexploitation; (2) excessive application of fertilizers in agricultural areas. Due to intensive groundwater pumping, the accelerated groundwater mineralization resulted in the local changes in hydrochemical facies of unconfined groundwater, while the strong mixture, especially a large influx of downward leakage from the unconfined aquifer into the confined aquifer, played a vital role in the fundamental variation of hydrochemical facies in confined aquifer. The nitrate contamination is mainly controlled by the local hydrogeological settings coupled with the traditional flood irrigation. The deeper insight into geochemical evolution of

  13. Measuring and computing natural ground-water recharge at sites in south-central Kansas

    USGS Publications Warehouse

    Sophocleous, M.A.; Perry, C.A.

    1987-01-01

    To measure the natural groundwater recharge process, two sites in south-central Kansas were instrumented with sensors and data microloggers. The atmospheric-boundary layer and the unsaturated and saturated soil zones were monitored as a single regime. Direct observations also were used to evaluate the measurements. Atmospheric sensors included an anemometer, a tipping-bucket rain gage, an air-temperature thermistor, a relative-humidity probe, a net radiometer, and a barometric-pressure transducer. Sensors in the unsaturated zone consisted of soil-temperature thermocouples, tensiometers coupled with pressure transducers and dial gages, gypsum blocks, and a neutron-moisture probe. The saturated-zone sensors consisted of a water-level pressure transducer, a conventional float gage connected to a variable potentiometer, soil thermocouples, and a number of multiple-depth piezometers. Evaluation of the operation of these sensors and recorders indicates that certain types of equipment, such as pressure transducers, are very sensitive to environmental conditions. A number of suggestions aimed at improving instrumentation of recharge investigations are outlined. Precipitation and evapotranspiration data, taken together with soil moisture profiles and storage changes, water fluxes in the unsaturated zone and hydraulic gradients in the saturated zone at various depths, soil temperature, water table hydrographs, and water level changes in nearby wells, describe the recharge process. Although the two instrumented sites are located in sand-dune environments in area characterized by a shallow water table and a sub-humid continental climate, a significant difference was observed in the estimated total recharge. The estimates ranged from less than 2.5 mm at the Zenith site to approximately 154 mm at the Burrton site from February to June 1983. The principal reasons that the Burrton site had more recharge than the Zenith site were more precipitation, less evapotranspiration, and a

  14. Supply rates of natural U-Th series radionuclides from aquifer solids into groundwater

    NASA Astrophysics Data System (ADS)

    Hussain, N.

    Supply rates of 224Ra and 212Pb from zircon and monazite grains to the aqueous phase are experimentally determined by dispersing these minerals in 1N nitric acid and PRL (Physical Research Laboratory) groundwater. In nitric acid medium, recoiled 224Ra and 212Pb behave conservatively and are not removed by solid surfaces. However, in groundwater, 212Pb is removed from the aqueous phase. A model relating the actual supply ratio of 212Pb/224Ra, the measured activities of 224Ra and 212Pb in the leachates at different times of contact and the first order removal rate constant of 212Pb is developed. At steady state, the supply ratio of 212Pb/224Ra in nitric acid from zircon and in groundwater from monazite is evaluated to be a unique value 2.3±0.3 which agrees with the model predicted value of 2.67 based on alpha recoil supply of the nuclides and their precursors. The residence time of 212Pb in groundwater, with respect to its first order removal, is estimated to be of the order of 39 minutes.

  15. Saturated zone denitrification: potential for natural attenuation of nitrate contamination in shallow groundwater under dairy operations.

    PubMed

    Singleton, M J; Esser, B K; Moran, J E; Hudson, G B; McNab, W W; Harter, T

    2007-02-01

    We present results from field studies at two central California dairies that demonstrate the prevalence of saturated-zone denitrification in shallow groundwater with 3H/ 3He apparent ages of < 35 years. Concentrated animal feeding operations are suspected to be major contributors of nitrate to groundwater, but saturated zone denitrification could mitigate their impact to groundwater quality. Denitrification is identified and quantified using N and O stable isotope compositions of nitrate coupled with measurements of excess N2 and residual NO3(-) concentrations. Nitrate in dairy groundwater from this study has delta15N values (4.3-61 per thousand), and delta18O values (-4.5-24.5 per thousand) that plot with delta18O/delta15N slopes of 0.47-0.66, consistent with denitrification. Noble gas mass spectrometry is used to quantify recharge temperature and excess air content. Dissolved N2 is found at concentrations well above those expected for equilibrium with air or incorporation of excess air, consistent with reduction of nitrate to N2. Fractionation factors for nitrogen and oxygen isotopes in nitrate appear to be highly variable at a dairy site where denitrification is found in a laterally extensive anoxic zone 5 m below the water table, and at a second dairy site where denitrification occurs near the water table and is strongly influenced by localized lagoon seepage. PMID:17328180

  16. Long-term natural attenuation of carbon and nitrogen within a groundwater plume after removal of the treated wastewater source

    USGS Publications Warehouse

    Repert, D.A.; Barber, L.B.; Hess, K.M.; Keefe, S.H.; Kent, D.B.; LeBlanc, D.R.; Smith, R.L.

    2006-01-01

    Disposal of treated wastewater for more than 60 years onto infiltration beds on Cape Cod, Massachusetts produced a groundwater contaminant plume greater than 6 km long in a surficial sand and gravel aquifer. In December 1995 the wastewater disposal ceased. A long-term, continuous study was conducted to characterize the post-cessation attenuation of the plume from the source to 0.6 km downgradient. Concentrations and total pools of mobile constituents, such as boron and nitrate, steadily decreased within 1-4 years along the transect. Dissolved organic carbon loads also decreased, but to a lesser extent, particularly downgradient of the infiltration beds. After 4 years, concentrations and pools of carbon and nitrogen in groundwater were relatively constant with time and distance, but substantially elevated above background. The contaminant plume core remained anoxic for the entire 10-year study period; temporal patterns of integrated oxygen deficit decreased slowly at all sites. In 2004, substantial amounts of total dissolved carbon (7 mol C m-2) and fixed (dissolved plus sorbed) inorganic nitrogen (0.5 mol N m-2) were still present in a 28-m vertical interval at the disposal site. Sorbed constituents have contributed substantially to the dissolved carbon and nitrogen pools and are responsible for the long-term persistence of the contaminant plume. Natural aquifer restoration at the discharge location will take at least several decades, even though groundwater flow rates and the potential for contaminant flushing are relatively high.

  17. Accumulation of natural SF6 in the sedimentary aquifers of the North China Plain as a restriction on groundwater dating.

    PubMed

    von Rohden, Christoph; Kreuzer, Andreas; Chen, Zongyu; Aeschbach-Hertig, Werner

    2010-09-01

    We employed environmental tracers ((3)H-(3)He, SF(6)) in a study investigating the groundwater recharge in the North China Plain (NCP), a sedimentary aquifer system consisting of fluvial and alluvial river deposits near the city of Shijiazhuang. The (3)H-(3)He dating method revealed reasonable results for the young groundwater with ages covering the range of recent to ~40 a. SF(6) samples were taken in parallel for independent dating and to compare the applicability of both methods. However, the SF(6)-results are influenced and, in part, dominated by a systematic non-atmospheric component, revealing that the dating with SF(6) is unreliable in this region. A correlation of non-atmospheric SF(6) and (3)H-(3)He ages suggests a continuous accumulation of natural SF(6) in the groundwater of the NCP aquifers. Although terrigenic SF(6) has previously been associated with crystalline or igneous rocks, our results indicate that it can also be accumulated in sandy aquifers on the timescale relevant for SF(6) dating. PMID:20603738

  18. Combined estimation of specific yield and natural recharge in a semi-arid groundwater basin with irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Maréchal, J. C.; Dewandel, B.; Ahmed, S.; Galeazzi, L.; Zaidi, F. K.

    2006-09-01

    SummaryA water budget approach is developed to jointly estimate specific yield and natural recharge in an unconfined aquifer with significant seasonal water table fluctuations. Water table fluctuations are due to distinct seasonality in groundwater recharge. The separation of the hydrologic year into two (or more) extended seasons of recharge (wet season) and no-recharge (dry season) with accompanying changes in water table allows for a split use of the water table fluctuation (WTF) method, first to estimate specific yield from the water table drop during the dry season (no recharge) and, second, to estimate recharge from the water table rise during the wet season, after considering all other water budget components explicitly. The latter includes explicit computation of groundwater storage with the WTF method. The application of the WTF method requires a large number of water level measurements throughout the unconfined aquifer before and after each season. The advantage of the method is that specific yield and recharge are estimated at the scale of interest to basin hydrologic studies and that the method requires no extensive in situ instrumentation network. Here, the method is demonstrated through a case study in a fractured hard-rock aquifer subject to intensive groundwater pumping for irrigation purposes.

  19. Using natural distributions of short-lived radium isotopes to quantify groundwater discharge and recharge

    USGS Publications Warehouse

    Krest, J.M.; Harvey, J.W.

    2003-01-01

    Radium activity in pore water of wetland sediments often differs from the amount expected from local production, decay, and exchange with solid phases. This disequilibrium results from vertical transport of radium with groundwater that flows between the underlying aquifer and surface water. In situations where groundwater recharge or discharge is significant, the rate of vertical water flow through wetland sediment can be determined from the radium disequilibrium by a combined model of transport, production, decay, and exchange with solid phases. We have developed and tested this technique at three sites in the freshwater portion of the Everglades by quantifying vertical advective velocities in areas with persistent groundwater recharge or discharge and estimating a coefficient of dispersion at a site that is subject to reversals between recharge and discharge. Groundwater velocities (v) were determined to be between 0 and -0.5 cm d-1 for a recharge site and 1.5 ?? 0.4 cm d-1 for a discharge site near Levee 39 in the Everglades. Strong gradients in 223Ra and 224Ra usually occurred at the base of the peat layer, which avoided the problems of other tracers (e.g., chloride) for which greatest sensitivity occurs near the peat surface - a zone readily disturbed by processes unrelated to groundwater flow. This technique should be easily applicable to any wetland system with different production rates of these isotopes in distinct sedimentary layers or surface water. The approach is most straightforward in systems where constant pore-water ionic strength can be assumed, simplifying the modeling of radium exchange.

  20. Potential impacts on groundwater resources of deep CO2 storage: natural analogues for assessing potential chemical effects

    NASA Astrophysics Data System (ADS)

    Lions, J.; Gale, I.; May, F.; Nygaard, E.; Ruetters, H.; Beaubien, S.; Sohrabi, M.; Hatzignatiou, D. G.; CO2GeoNet Members involved in the present study Team

    2011-12-01

    Carbon dioxide Capture and Storage (CCS) is considered as one of the promising options for reducing atmospheric emissions of CO2 related to human activities. One of the main concerns associated with the geological storage of CO2 is that the CO2 may leak from the intended storage formation, migrate to the near-surface environment and, eventually, escape from the ground. This is a concern because such leakage may affect aquifers overlying the storage site and containing freshwater that may be used for drinking, industry and agriculture. The IEA Greenhouse Gas R&D Programme (IEAGHG) recently commissioned the CO2GeoNet Association to undertake a review of published and unpublished literature on this topic with the aim of summarizing 'state of the art' knowledge and identifying knowledge gaps and research priorities in this field. Work carried out by various CO2GeoNet members was also used in this study. This study identifies possible areas of conflict by combining available datasets to map the global and regional superposition of deep saline formations (DSF) suitable for CO2 storage and overlying fresh groundwater resources. A scenario classification is developed for the various geological settings where conflict could occur. The study proposes two approaches to address the potential impact mechanisms of CO2 storage projects on the hydrodynamics and chemistry of shallow groundwater. The first classifies and synthesizes changes of water quality observed in natural/industrial analogues and in laboratory experiments. The second reviews hydrodynamic and geochemical models, including coupled multiphase flow and reactive transport. Various models are discussed in terms of their advantages and limitations, with conclusions on possible impacts on groundwater resources. Possible mitigation options to stop or control CO2 leakage are assessed. The effect of CO2 pressure in the host DSF and the potential effects on shallow aquifers are also examined. The study provides a review of

  1. Naturally-Occurring Radionuclides In Drinking Water From Surface And Groundwater Reservoirs

    SciTech Connect

    Carvalho, F. P.; Madruga, M. J.; Oliveira, J. M.; Lopes, I.; Ferrador, G.; Sequeira, M. M.

    2008-08-07

    Radioactivity in water for human consumption is under closer scrutiny than ever before and many countries adopted guideline values based on total alpha and total beta activity measurements. Although most waters from surface circulation meet these guidelines, it is frequently found that groundwater exceed guideline values. Results of water analyses by alpha spectrometry clarified that the main radionuclides present are from the uranium decay series, such as uranium isotopes, radium ({sup 226}Ra), radon ({sup 222}Rn), and also {sup 210}Pb and {sup 210}Po. Occasionally, groundwater displayed {sup 226}Ra concentrations higher than 1 Bq L{sup -1} and {sup 222}Rn concentrations above 1000 Bq L{sup -1}. Nevertheless, lack of conformity of these waters with guidelines adopted, generally, is not due to anthropogenic inputs.

  2. Uranium mineral - groundwater equilibration at the Palmottu natural analogue study site, Finland

    SciTech Connect

    Ahonen, L.; Ruskeeniemi, T.; Blomqvist, R.; Ervanne, H.; Jaakkola, T.

    1993-12-31

    The redox-potential, pH, chemical composition of fracture waters, and uraninite alteration associated with the Palmottu uranium mineralization, have been studied. The data have been interpreted by means of thermodynamic calculations. The results indicate equilibrium between uraninite, ferric hydroxide and groundwater in the bedrock of the study site. Partially oxidized uraninite (UO{sub 2.33}) and ferric hydroxide are in equilibrium with the fresh, slightly acidic and oxidized water type, while primary uraninite is stable with deeper waters that have a higher pH and lower Eh. Measured Eh-pH values of groundwater cluster within a relatively narrow range indicating buffering by heterogeneous redox-processes. A good consistency between measured Eh and analyzed uranium oxidation states was observed.

  3. Analysis of the groundwater monitoring controversy at the Pavillion, Wyoming natural gas field.

    PubMed

    Stephens, Daniel B

    2015-01-01

    The U.S. Environmental Protection Agency (EPA) was contacted by citizens of Pavillion, Wyoming 6 years ago regarding taste and odor in their water wells in an area where hydraulic fracturing operations were occurring. EPA conducted a field investigation, including drilling two deep monitor wells, and concluded in a draft report that constituents associated with hydraulic fracturing had impacted the drinking water aquifer. Following extensive media coverage, pressure from state and other federal agencies, and extensive technical criticism from industry, EPA stated the draft report would not undergo peer review, that it would not rely on the conclusions, and that it had relinquished its lead role in the investigation to the State of Wyoming for further investigation without resolving the source of the taste and odor problem. Review of the events leading up to EPA's decision suggests that much of the criticism could have been avoided through improved preproject planning with clear objectives. Such planning would have identified the high national significance and potential implications of the proposed work. Expanded stakeholder involvement and technical input could have eliminated some of the difficulties that plagued the investigation. However, collecting baseline groundwater quality data prior to initiating hydraulic fracturing likely would have been an effective way to evaluate potential impacts. The Pavillion groundwater investigation provides an excellent opportunity for improving field methods, report transparency, clarity of communication, and the peer review process in future investigations of the impacts of hydraulic fracturing on groundwater. PMID:25231140

  4. Natural radioactivity levels in granitic plutons and groundwaters in Southeast part of Eskisehir, Turkey.

    PubMed

    Orgün, Y; Altinsoy, N; Gültekin, A H; Karahan, G; Celebi, N

    2005-08-01

    The present work investigated the radioactivity level of the granitoid plutons and its effect on the groundwaters in the southeast part of Eskisehir. Fourteen granitic samples from the Kaymaz and Sivrihisar plutons and 11 groundwater samples from the near vicinity of the pluton were analyzed. The activity concentrations measured for (238)U and (232)Th ranged from 43.59+/-2 to 651.80+/-24 Bq/kg, and 51.16+/-3 to 351.94+/-13 Bq/kg, respectively. The activity concentrations obtained for (40)K varied from 418.50+/-17 to 1618.03+/-66 Bq/kg. The absorbed dose rates in air outdoors ranged from 87.14 to 531.81 nGy/h. All the results obtained from the Kaymaz pluton are higher than those from the Sivrihisar. The U (ave. 16.6 ppm) and Th (ave. 49.9 ppm) values of the Kaymaz pluton are higher than the average concentrations of the magmatic rocks of granitic composition. These results are consistent with high dose rates of the pluton. The gross-alpha activities in the groundwater samples ranged from 0.009 to 1.64 Bq/l and the gross-beta activities from 0.006 to 0.89 Bq/l. The highest gross-alpha value was found in the sample taken from near the Kaymaz pluton. The concentrations of (222)Rn varied from 0.060 to 0.557 Bq/l. PMID:15921915

  5. Natural and enhanced anaerobic degradation of 1,1,1-trichloroethane and its degradation products in the subsurface--a critical review.

    PubMed

    Scheutz, Charlotte; Durant, Neal D; Hansen, Maria H; Bjerg, Poul L

    2011-04-01

    1,1,1-Trichloroethane (TCA) in groundwater is susceptible to a variety of natural degradation mechanisms. Evidence of intrinsic decay of TCA in aquifers is commonly observed; however, TCA remains a persistent pollutant at many sites and some of the daughter products that accumulate from intrinsic decay of TCA have been determined to be more toxic than the parent compound. Research advances from the past decade indicate that in situ enhanced reductive dechlorination (ERD) offers promise as a cost-effective solution toward the cleanup of groundwater contaminated with TCA and its transformation daughter products. Laboratory studies have demonstrated that pure or mixed cultures containing certain Dehalobacter (Dhb) bacteria can catalyze respiratory dechlorination of TCA and 1,1-dichloroethane (1,1-DCA) to monochloroethane (CA) in groundwater systems. 16S rRNA Dhb gene probes have been used as biomarkers in groundwater samples to both assess ERD potential and quantify growth of Dhb in ERD applications at TCA sites. Laboratory findings suggest that iron-bearing minerals and methanogenic bacteria that co-occur in reduced aquifers may synergistically affect dechlorination of TCA. Despite these advances, a number of significant challenges remain, including an inability of any known cultures to completely dechlorinate TCA to ethane. CA is commonly observed as a terminal product of the biological reductive dechlorination of TCA and 1,1-DCA. Also important is the lack of rigorous field studies demonstrating the utility of bioaugmentation with Dhb cultures for remediation of TCA in the field. In this paper we review the state-of-the-science of TCA degradation in aquifers, examining results from both laboratory experiments and twenty-two field case studies, focusing on the capabilities and limits of ERD technology, and identifying aspects of the technology that warrant further development. PMID:21474158

  6. Natural recharge estimation and uncertainty analysis of an adjudicated groundwater basin using a regional-scale flow and subsidence model (Antelope Valley, California, USA)

    USGS Publications Warehouse

    Siade, Adam J.; Nishikawa, Tracy; Martin, Peter

    2015-01-01

    Groundwater has provided 50–90 % of the total water supply in Antelope Valley, California (USA). The associated groundwater-level declines have led the Los Angeles County Superior Court of California to recently rule that the Antelope Valley groundwater basin is in overdraft, i.e., annual pumpage exceeds annual recharge. Natural recharge consists primarily of mountain-front recharge and is an important component of the total groundwater budget in Antelope Valley. Therefore, natural recharge plays a major role in the Court’s decision. The exact quantity and distribution of natural recharge is uncertain, with total estimates from previous studies ranging from 37 to 200 gigaliters per year (GL/year). In order to better understand the uncertainty associated with natural recharge and to provide a tool for groundwater management, a numerical model of groundwater flow and land subsidence was developed. The transient model was calibrated using PEST with water-level and subsidence data; prior information was incorporated through the use of Tikhonov regularization. The calibrated estimate of natural recharge was 36 GL/year, which is appreciably less than the value used by the court (74 GL/year). The effect of parameter uncertainty on the estimation of natural recharge was addressed using the Null-Space Monte Carlo method. A Pareto trade-off method was also used to portray the reasonableness of larger natural recharge rates. The reasonableness of the 74 GL/year value and the effect of uncertain pumpage rates were also evaluated. The uncertainty analyses indicate that the total natural recharge likely ranges between 34.5 and 54.3 GL/year.

  7. Natural recharge estimation and uncertainty analysis of an adjudicated groundwater basin using a regional-scale flow and subsidence model (Antelope Valley, California, USA)

    NASA Astrophysics Data System (ADS)

    Siade, Adam; Nishikawa, Tracy; Martin, Peter

    2015-09-01

    Groundwater has provided 50-90 % of the total water supply in Antelope Valley, California (USA). The associated groundwater-level declines have led the Los Angeles County Superior Court of California to recently rule that the Antelope Valley groundwater basin is in overdraft, i.e., annual pumpage exceeds annual recharge. Natural recharge consists primarily of mountain-front recharge and is an important component of the total groundwater budget in Antelope Valley. Therefore, natural recharge plays a major role in the Court's decision. The exact quantity and distribution of natural recharge is uncertain, with total estimates from previous studies ranging from 37 to 200 gigaliters per year (GL/year). In order to better understand the uncertainty associated with natural recharge and to provide a tool for groundwater management, a numerical model of groundwater flow and land subsidence was developed. The transient model was calibrated using PEST with water-level and subsidence data; prior information was incorporated through the use of Tikhonov regularization. The calibrated estimate of natural recharge was 36 GL/year, which is appreciably less than the value used by the court (74 GL/year). The effect of parameter uncertainty on the estimation of natural recharge was addressed using the Null-Space Monte Carlo method. A Pareto trade-off method was also used to portray the reasonableness of larger natural recharge rates. The reasonableness of the 74 GL/year value and the effect of uncertain pumpage rates were also evaluated. The uncertainty analyses indicate that the total natural recharge likely ranges between 34.5 and 54.3 GL/year.

  8. Natural Oxidant Demand Variability, Potential Controls, and Implications for in Situ, Oxidation-Based Remediation of Contaminated Groundwater

    NASA Astrophysics Data System (ADS)

    Dettmer, A.; Cruz, S.; Dungan, B.; Holguin, F. O.; Ulery, A. L.; Hunter, B.; Carroll, K. C.

    2014-12-01

    Naturally occurring reduced species associated with subsurface materials can impose a significant natural oxidant demand (NOD), which is the bulk consumption of oxidants by soil water, minerals, and organic matter. Although injection of oxidants has been used for chemical transformation of organic contaminants, NOD represents a challenge for the in-situ delivery of oxidants as a remediation alternative. Co-injection of complexation agents with oxidants has been proposed to facilitate the delivery of oxidants for in situ chemical oxidation remediation of contaminated groundwater. This study investigates variability of NOD for different oxidants and sediments. The effect of the addition of various complexation agents, including EDTA, tween 80, hydroxypropyl-beta-cyclodextrin (HPCD), humic acid, and four generations of poly(amidoamine) (PAMAM) dendrimers, on the NOD was also examined. NOD was measured for a clay loam (collected from Air Force Plant 44 in Tucson, AZ). Varying amounts of biosolids were mixed with subsamples of the clay loam to create three additional reference soils in order to study the effect of organic matter and other soil characteristics on the NOD. Bench-scale laboratory experiments were conducted to determine the NOD for various oxidants, using the four soils, and replicated with and without various delivery agents. Measured NOD showed variability for each soil and oxidant composition. Additionally, significant differences were observed in NOD with the addition of delivery agents. The results support the elucidation of potential controls over NOD and have implications for in situ, oxidation-based remediation of contaminated groundwater.

  9. Anaerobic Process.

    PubMed

    Li, Wei-Zun; Qian, Yang; Chang, Chein-Chi; Ju, Meiting

    2015-10-01

    A review of the literature published in 2014 on the focus of Anaerobic Process. It is divided into the following sections. •Pretreatment •Organic waste •multiple-stage co-digestion •Process Methodology and Technology. PMID:26420080

  10. Enhanced Anaerobic Biodegradation of Benzene-Toluene-Ethylbenzene-Xylene-Ethanol Mixtures in Bioaugmented Aquifer Columns

    PubMed Central

    Da Silva, Marcio L. B.; Alvarez, Pedro J. J.

    2004-01-01

    Methanogenic flowthrough aquifer columns were used to investigate the potential of bioaugmentation to enhance anaerobic benzene-toluene-ethylbenzene-xylene (BTEX) degradation in groundwater contaminated with ethanol-blended gasoline. Two different methanogenic consortia (enriched with benzene or toluene and o-xylene) were used as inocula. Toluene was the only hydrocarbon degraded within 3 years in columns that were not bioaugmented, although anaerobic toluene degradation was observed after only 2 years of acclimation. Significant benzene biodegradation (up to 88%) was observed only in a column bioaugmented with the benzene-enriched methanogenic consortium, and this removal efficiency was sustained for 1 year with no significant decrease in permeability due to bioaugmentation. Benzene removal was hindered by the presence of toluene, which is a more labile substrate under anaerobic conditions. Real-time quantitative PCR analysis showed that the highest numbers of bssA gene copies (coding for benzylsuccinate synthase) occurred in aquifer samples exhibiting the highest rate of toluene degradation, which suggests that this gene could be a useful biomarker for environmental forensic analysis of anaerobic toluene bioremediation potential. bssA continued to be detected in the columns 1 year after column feeding ceased, indicating the robustness of the added catabolic potential. Overall, these results suggest that anaerobic bioaugmentation might enhance the natural attenuation of BTEX in groundwater contaminated with ethanol-blended gasoline, although field trials would be needed to demonstrate its feasibility. This approach may be especially attractive for removing benzene, which is the most toxic and commonly the most persistent BTEX compound under anaerobic conditions. PMID:15294807

  11. Model-based clustering of hydrochemical data to demarcate natural versus human impacts on bedrock groundwater quality in rural areas, South Korea

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Ho; Yun, Seong-Taek; Park, Seong-Sook; Joo, Yongsung; Kim, Tae-Seung

    2014-11-01

    Improved evaluation of anthropogenic contamination is required to sustainably manage groundwater resources. In this study, we investigated the hydrochemical measurements of 18 parameters from a total of 102 bedrock groundwater samples from two representative rural areas in South Korea. We used model-based clustering with a normal (Gaussian) mixture model to differentiate the contributions of natural versus anthropogenic processes to the observed groundwater quality. Water samples varied in hydrochemistry from a Ca-Na-HCO3 type to a Ca-HCO3-Cl type. The former type reflected derivation of major ions largely from water-rock interactions, while the latter type recorded varying degrees of anthropogenic contamination. Among the major dissolved ions, fluoride and nitrate were shown to be good indicators of the two types, respectively. The results of model-based clustering showed that the bivariate normal mixture model, which was based on the covariance of nitrate and fluoride, was more robust than multivariate analysis, and provided better discrimination between the anthropogenic and natural groundwater groups. Model-based clustering to measure the degree of cluster membership for each sample also showed a gradual change in groundwater chemistry due to mixing between the two water groups. This study provided an example of the successful application of model-based clustering to evaluate regional groundwater quality and demonstrated that better selection of the dimensional structure (i.e., selection of optimal variables and number of clusters) based on hydrochemistry was crucial in obtaining reasonable clustering results.

  12. Escherichia coli Attenuation by Fe Electrocoagulation in Synthetic Bengal Groundwater: Effect of pH and Natural Organic Matter.

    PubMed

    Delaire, Caroline; van Genuchten, Case M; Nelson, Kara L; Amrose, Susan E; Gadgil, Ashok J

    2015-08-18

    Technologies addressing both arsenic and microbial contamination of Bengal groundwater are needed. Fe electrocoagulation (Fe-EC), a simple process relying on the dissolution of an Fe(0) anode to produce Fe(III) precipitates, has been shown to efficiently remove arsenic from groundwater at low cost. We investigated Escherichia coli (E. coli) attenuation by Fe-EC in synthetic Bengal groundwater as a function of Fe dosage rate, total Fe dosed, pH, and presence of natural organic matter (NOM). A 2.5 mM Fe dosage simultaneously achieved over 4-log E. coli attenuation and arsenic removal from 450 to below 10 μg/L. E. coli reduction was significantly enhanced at pH 6.6 compared to pH 7.5, which we linked to the decreased rate of Fe(II) oxidation at lower pH. 3 mg/L-C of NOM (Suwanee River fulvic acid) did not significantly affect E. coli attenuation. Live-dead staining and comparisons of Fe-EC with chemical coagulation controls showed that the primary mechanism of E. coli attenuation is physical removal with Fe(III) precipitates, with inactivation likely contributing as well at lower pH. Transmission electron microscopy showed that EC precipitates adhere to and bridge individual E. coli cells, resulting in large bacteria-Fe aggregates that can be removed by gravitational settling. Our results point to the promising ability of Fe-EC to treat arsenic and bacterial contamination simultaneously at low cost. PMID:26172118

  13. Altitude, age, and quality of groundwater, Papio-Missouri River Natural Resources District, eastern Nebraska, 1992 to 2009

    USGS Publications Warehouse

    McGuire, Virginia L.; Ryter, Derek W.; Flynn, Amanda S.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Papio-Missouri River Natural Resources District (PMRNRD), conducted this study to map the water-level altitude of 2009 within the Elkhorn River Valley, Missouri River Valley, and Platte River Valley alluvial aquifers; to present the predevelopment potentiometric-surface altitude within the Dakota aquifer; and to describe the age and quality of groundwater in the five principal aquifers of the PMRNRD in eastern Nebraska using data collected from 1992 to 2009. In addition, implications of alternatives to the current PMRNRD groundwater-quality monitoring approach are discussed. In the PMRNRD, groundwater altitude, relative to National Geodetic Vertical Datum of 1929, ranged from about 1,080 feet (ft) to 1,180 ft in the Elkhorn River Valley alluvial aquifer and from about 960 ft to 1,080 ft in the Missouri River Valley and Platte River Valley alluvial aquifers. In the PMRNRD, the estimated altitude of the potentiometric surface of the Dakota aquifer, predevelopment, ranged from about 1,100 ft to 1,200 ft. To assess groundwater age and quality, groundwater samples were collected from a total of 217 wells from 1992 to 2009 for analysis of various analytes. Groundwater samples collected in the PMRNRD from 1992 to 2009 and interpreted in this report were analyzed for age-dating analytes (chlorofluorocarbons), dissolved gases, major ions, trace elements, nutrients, stable isotope ratios, pesticides and pesticide degradates, volatile organic compounds, explosives, and 222radon. Apparent groundwater age was estimated from concentrations of chlorofluorocarbons measured in samples collected in 2000. Apparent groundwater-recharge dates ranged from older than 1940 in samples from wells screened in the Missouri River Valley alluvial aquifer to the early 1980s in samples from wells screened in the Dakota aquifer. Concentrations of major ions in the most recent sample per well collected from 1992 to 2009 indicate that the

  14. High-frequency transfer of a naturally occurring chromosomal tetracycline resistance element in the ruminal anaerobe Butyrivibrio fibrisolvens.

    PubMed Central

    Scott, K P; Barbosa, T M; Forbes, K J; Flint, H J

    1997-01-01

    Butyrivibrio fibrisolvens strains resistant to tetracycline were isolated from the bovine rumen. Two of three Tcr B. fibrisolvens tested were able to donate tetracycline resistance at frequencies ranging from 10(-7) to 10(-1) per donor cell in anaerobic filter matings to a rifampin-resistant mutant of the type strain of B.fibrisolvens, 2221R. The recipient strain 2221R exhibited rapid autoaggregation, which might be a factor in the high transfer rates observed. Tcr transconjugants of B. fibrisolvens 2221R were also capable of further transferring tetracycline resistance to a fusidic acid-resistant mutant, 2221F. Comparison of genomic DNAs by pulsed-field gel electrophoresis demonstrated altered band profiles in transconjugants, consistent with the acquisition of a large mobile chromosomal element. The transferable elements from the two B. fibrisolvens donors 1.23 and 1.230 (TnB123 and TnB1230, respectively) showed the same preferred insertion site in the B. fibrisolvens 2221R chromosome and are likely to be similar, or identical, elements. Hybridization experiments showed no close relationship between TnB1230 and int-xis regions from Tn916 or Tn5253. Although DNA from the B. fibrisolvens donor strains hybridized with probes carrying tet(M) or tet(O) sequences, transconjugants were found to have acquired a distinct band that hybridized only weakly with these probes, suggesting that a second, distantly related Tcr determinant had been transferred. PMID:9292992

  15. EVALUATING MONITORED NATURAL ATTENUATION FOR RADIONUCLIDE AND INORGANIC CONTAMINANTS IN GROUNDWATER

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) for inorganic contaminants is dependent on naturally occurring processes in the subsurface that act without human intervention to reduce the mass, toxicity, mobility, volume or concentration of contaminants. EPA is developing a technical refer...

  16. EVALUATING MONITORED NATURAL ATTENUATION FOR RADIONUCLIDE & ORGANIC CONTAMINATION IN GROUNDWATER (SALT LAKE CITY, UT)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) for radionuclides and inorganic contaminants is dependent on naturally occurring processes in the subsurface that act without human intervention to reduce the mass, toxicity, mobility, volume or concentration of contaminants. EPA is developing ...

  17. Anaerobic sealing

    SciTech Connect

    Hayre, J.

    1986-05-01

    Anaerobic sealants offer an alternative to conventional methods of joint repair on mains operating at low and medium pressures. The method does not require highly skilled personnel who are diligent in ensuring that the necessary standards of preparation and seal application are achieved. British Gas' experience has shown that lead joints that do not contain yarn or where the yarn has deteriorated are difficult to seal. The evidence so far indicates that yarn is important in ensuring that the low viscosity sealant rapidly wicks around the joint during the injection operation. It is obvious that more research and development is needed in this field, but anaerobic sealing of leaking joints in an effective, innovative method of joint repair.

  18. Natural bioreclamation of alkylbenzenes (BTEX) from a gasoline spill in methanogenic groundwater. Book chapter

    SciTech Connect

    Wilson, J.T.; Kampbell, D.H.; Armstrong, J.

    1994-01-01

    A spill of gasoline from underground storage tanks (USTS) at the Sleeping Bear Dunes National Lakeshore in Benzie County, Michigan, produced a plume of contamination that reached the banks of the Platte River. The plume was short (70 feet) and it had a short residence time (5 to 53 weeks). The plume was in transmissive glacial sands and gravels. The groundwater is cold (10 to 11 C), hard (alkalinity 200 to 350 milligrams/L), and well buffered (pH 6.1 to 7.6). Along the most contaminated flow path, methanogenesis, nitrate reduction, sulfate reduction, iron reduction, and oxygen respiration accepted enough electrons to destroy 30, 14, 4.2, 1.1, and 0.8 milligrams/L of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds) respectively. The actual concentration of BTEX compounds consumed was 42 milligrams/L.

  19. Several natural indicators of radial well ageing at the Belgrade groundwater source, part 2.

    PubMed

    Dimkić, M; Pusić, M; Obradović, V; Djurić, D

    2011-01-01

    From 2005 to 2009, research was conducted at the Belgrade Groundwater Source (BGWS) to investigate the process of clogging of wells with horizontal lateral screens (radial wells). The clogging process was monitored via the kinetics of the increase in hydraulic losses at the laterals. A correlation of this process with the redox potential, the iron concentration in water, and the microbial population growth at the laterals and in their immediate vicinity was established. Research outcomes are presented here from a study of five wells where laterals were replaced between 2006 and 2008. Derived dependencies were later used to define the preferred approach to the installation and maintenance of well laterals at the BGWS. Results contribute to the study of well ageing caused by biochemical clogging. PMID:22049750

  20. Ground-water pumpage and artificial recharge estimates for calendar year 2000 and average annual natural recharge and interbasin flow by hydrographic area, Nevada

    USGS Publications Warehouse

    Lopes, Thomas J.; Evetts, David M.

    2004-01-01

    Nevada's reliance on ground-water resources has increased because of increased development and surface-water resources being fully appropriated. The need to accurately quantify Nevada's water resources and water use is more critical than ever to meet future demands. Estimated ground-water pumpage, artificial and natural recharge, and interbasin flow can be used to help evaluate stresses on aquifer systems. In this report, estimates of ground-water pumpage and artificial recharge during calendar year 2000 were made using data from a variety of sources, such as reported estimates and estimates made using Landsat satellite imagery. Average annual natural recharge and interbasin flow were compiled from published reports. An estimated 1,427,100 acre-feet of ground water was pumped in Nevada during calendar year 2000. This total was calculated by summing six categories of ground-water pumpage, based on water use. Total artificial recharge during 2000 was about 145,970 acre-feet. At least one estimate of natural recharge was available for 209 of the 232 hydrographic areas (HAs). Natural recharge for the 209 HAs ranges from 1,793,420 to 2,583,150 acre-feet. Estimates of interbasin flow were available for 151 HAs. The categories and their percentage of the total ground-water pumpage are irrigation and stock watering (47 percent), mining (26 percent), water systems (14 percent), geothermal production (8 percent), self-supplied domestic (4 percent), and miscellaneous (less than 1 percent). Pumpage in the top 10 HAs accounted for about 49 percent of the total ground-water pumpage. The most ground-water pumpage in an HA was due to mining in Pumpernickel Valley (HA 65), Boulder Flat (HA 61), and Lower Reese River Valley (HA 59). Pumpage by water systems in Las Vegas Valley (HA 212) and Truckee Meadows (HA 87) were the fourth and fifth highest pumpage in 2000, respectively. Irrigation and stock watering pumpage accounted for most ground-water withdrawals in the HAs with the sixth

  1. Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site—10281

    SciTech Connect

    Waugh, W.J.; Miller, D.E.; Morris, S.A.; Sheader, L.R.; Glenn, E.P.; Moore, D.; Carroll, K.C.; Benally, L.; Roanhorse, M.; Bush, R.P.; none,

    2010-03-07

    The U.S. Department of Energy (DOE), the Navajo Nation, and the University of Arizona are exploring natural and enhanced attenuation remedies for groundwater contamination at a former uranium-ore processing site near Monument Valley, Arizona. DOE removed radioactive tailings from the Monument Valley site in 1994. Nitrate and ammonium, waste products of the milling process, remain in an alluvial groundwater plume spreading from the soil source where tailings were removed. Planting and irrigating two native shrubs, fourwing saltbush and black greasewood, markedly reduced both nitrate and ammonium in the source area over an 8-year period. Total nitrogen dropped from 350 mg/kg in 2000 to less than 200 mg/kg in 2008. Most of the reduction is attributable to irrigation-enhanced microbial denitrification rather than plant uptake. However, soil moisture and percolation flux monitoring show that the plantings control the soil water balance in the source area, preventing additional leaching of nitrogen compounds. Enhanced denitrification and phytoremediation also look promising for plume remediation. Microcosm experiments, nitrogen isotopic fractionation analysis, and solute transport modeling results suggest that (1) up to 70 percent of nitrate in the plume has been lost through natural denitrification since the mill was closed in 1968, and (2) injection of ethanol may accelerate microbial denitrification in plume hot spots. A field-scale ethanol injection pilot study is underway. Landscape-scale remote sensing methods developed for the project suggest that transpiration from restored native phreatophyte populations rooted in the aquifer could limit further expansion of the plume. An evaluation of landfarm phytoremediation, the irrigation of native shrub plantings with high nitrate water pumped from the alluvial aquifer, is also underway.

  2. Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

    PubMed

    Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

    2016-01-01

    A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kg COD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process. PMID:27120630

  3. Water and rock geochemistry, geologic cross sections, geochemical modeling, and groundwater flow modeling for identifying the source of groundwater to Montezuma Well, a natural spring in central Arizona

    USGS Publications Warehouse

    Johnson, Raymond H.; DeWitt, Ed; Wirt, Laurie; Arnold, L. Rick; Horton, John D.

    2011-01-01

    The National Park Service (NPS) seeks additional information to better understand the source(s) of groundwater and associated groundwater flow paths to Montezuma Well in Montezuma Castle National Monument, central Arizona. The source of water to Montezuma Well, a flowing sinkhole in a desert setting, is poorly understood. Water emerges from the middle limestone facies of the lacustrine Verde Formation, but the precise origin of the water and its travel path are largely unknown. Some have proposed artesian flow to Montezuma Well through the Supai Formation, which is exposed along the eastern margin of the Verde Valley and underlies the Verde Formation. The groundwater recharge zone likely lies above the floor of the Verde Valley somewhere to the north or east of Montezuma Well, where precipitation is more abundant. Additional data from groundwater, surface water, and bedrock geology are required for Montezuma Well and the surrounding region to test the current conceptual ideas, to provide new details on the groundwater flow in the area, and to assist in future management decisions. The results of this research will provide information for long-term water resource management and the protection of water rights.

  4. Estimates of natural ground-water discharge and characterization of water quality in Dry Valley, Washoe County, West-Central Nevada, 2002-2003

    USGS Publications Warehouse

    Berger, David L.; Maurer, Douglas K.; Lopes, Thomas J.; Halford, Keith J.

    2004-01-01

    The Dry Valley Hydrographic Area is being considered as a potential source area for additional water supplies for the Reno-Sparks area, which is about 25 miles south of Dry Valley. Current estimates of annual ground-water recharge to Dry Valley have a considerable range. In undeveloped valleys, such as Dry Valley, long-term ground-water discharge can be assumed the same as long-term ground-water recharge. Because estimating ground-water discharge has more certainty than estimating ground-water recharge from precipitation, the U.S. Geological Survey, in cooperation with Washoe County, began a three-year study to re-evaluate the ground-water resources by estimating natural ground-water discharge and characterize ground-water quality in Dry Valley. In Dry Valley, natural ground-water discharge occurs as subsurface outflow and by ground-water evapotranspiration. The amount of subsurface outflow from the upper part of Dry Valley to Winnemucca and Honey Lake Valleys likely is small. Subsurface outflow from Dry Valley westward to Long Valley, California was estimated using Darcy's Law. Analysis of two aquifer tests show the transmissivity of poorly sorted sediments near the western side of Dry Valley is 1,200 to 1,500 square feet per day. The width of unconsolidated sediments is about 4,000 feet between exposures of tuffaceous deposits along the State line, and decreases to about 1,500 feet (0.5 mile) west of the State line. The hydraulic gradient east and west of the State line ranges from 0.003 to 0.005 foot per foot. Using these values, subsurface outflow to Long Valley is estimated to be 50 to 250 acre-feet per year. Areas of ground-water evapotranspiration were field mapped and partitioned into zones of plant cover using relations derived from Landsat imagery acquired July 8, 2002. Evapotranspiration rates for each plant-cover zone were multiplied by the corresponding area and summed to estimate annual ground-water evapotranspiration. About 640 to 790 acre-feet per

  5. Multicomponent reactive transport in discrete fractures. II: Infiltration of hyperalkaline groundwater at Maqarin, Jordan, a natural analogue site

    NASA Astrophysics Data System (ADS)

    Steefel, C. I.; Lichtner, P. C.

    1998-08-01

    A numerical multicomponent reactive transport model described fully in Steefel and Lichtner (1998)[Steefel, C.I., Lichtner, P.C., 1998. Multicomponent reactive transport in discrete fractures, I. Controls on reaction front geometry. J. Hydrol. (in press)] is used to simulate the infiltration of hyperalkaline groundwater along discrete fractures at Maqarin, Jordan, a site considered as a natural analogue to cement-bearing nuclear waste repositories. In the Eastern Springs area at Maqarin, two prominent sets of sub-parallel fractures trending NW-SE are approximately perpendicular to the local water table contours, with the slope of the water table indicating north-westward flow. Extensive mineralogic investigations [Alexander W.R. (Ed.), 1992. A natural analogue study of cement-buffered, hyperalkaline groundwaters and their interaction with a sedimentary host rock. NAgrA Technical Report (NTB 91-10), Wettingen, Switzerland; Milodowski, A.E., Hyslop, E.K., Pearce, J.M., Wetton, P.D., Kemp, S.J., Longworth, G., Hodginson, E., and Hughes, C.R., 1998. Mineralogy and geochemistry of the western springs area. In: Smellie, J.A.T. (ed.), 1998: Maqarin Natural Analogue Study: Phase III. SKB Technical Report TR98-04, Stockholm, Sweden] indicate that the width of intense rock alteration zone bordering the fractures changes from about 4 mm at one locality (the M1 sampling site) to approximately 1 mm 100 m to the north-west in the flow direction (the M2 site), suggesting a lessening of alteration intensity in that direction. Using this information, the dimensionless parameter δ v/φ D' (φ=porosity, D'=effective diffusion coefficient in rock matrix, δ=fracture aperture, and v=fluid velocity in the fracture) and measurements of the local hydraulic head gradient and effective diffusion coefficient in the rock matrix, a mean fracture aperture of 0.194 mm is calculated assuming the cubic law applies. This information, in combination with measured groundwater compositions at the

  6. Natural background levels and threshold values of chemical species in three large-scale groundwater bodies in Northern Italy.

    PubMed

    Molinari, Antonio; Guadagnini, Laura; Marcaccio, Marco; Guadagnini, Alberto

    2012-05-15

    We analyze natural background levels (NBLs) and threshold values (TVs) of spatially distributed chemical species (NH(4), B and As) which may be a potential pressure and concern in three large scale alluvial and fluvio-deltaic aquifers at different depths of the Apennines and Po river plains in Emilia-Romagna, Northern Italy. Our results are based on statistical methodologies designed to separate the natural and anthropogenic contributions in monitored concentrations by modeling the empirical distribution of the detected concentration with a mixture of probability density functions. Available chemical observations are taken over a 20 years period and are associated with different depths and cover planar investigation scales of the order of hundreds of kilometers. High concentration values detected for NH(4) and B appear to be related to high natural background levels. Due to interaction with the host rock in different geochemical environments we observed that concentration vary in time and space (including in depth) consistently with the hydrogeochemical features and the occurrence of natural attenuation mechanisms in the analyzed reservoirs. Conversely, estimated As NBLs are not consistent with the conceptual model of the hydrogeochemical behavior of the systems analyzed and experimental evidences of As content in aquifer cores. This is due to the inability of these techniques to incorporate the complex dynamics of the processes associated with the specific hydrogeochemical setting. Statistical analyses performed upon aggregating the concentration data according to different time observation windows allow identifying temporal dynamics of NBLs and TVs of target compounds within the observation time frame. Our results highlight the benefit of a dynamic monitoring process and analysis of well demarcated groundwater bodies to update the associated NBLs as a function of the temporal dependence of natural processes occurring in the subsurface. Monitoring protocols could

  7. Methanogenic biodegradation of creosote contaminants in natural and simulated ground-water ecosystems

    USGS Publications Warehouse

    Godsy, E. Michael; Goerlitz, Donald; Grbic-Galic, Dunja

    1992-01-01

    Wastes from a wood preserving plant in Pensacola, Florida have contaminated the near-surface sand-and-gravel aquifer with creosote-derived compounds and pentachlorophenol. Contamination resulted from the discharge of plant waste waters to and subsequent seepage from unlined surface impoundments that were in direct hydraulic contact with the ground water. Two distinct phases resulted when the creosote and water mixed: a denser than water hydrocarbon phase that moved vertically downward, and an organic-rich aqueous phase that moved laterally with the ground-water flow. The aqueous phase is enriched in organic acids, phenolic compounds, single- and double-ring nitrogen, sulfur, and oxygen containing compounds, and single- and double-ring aromatic hydrocarbons. The ground water is devoid of dissolved O2, is 60-70% saturated with CH4 and contains H2S. Field analyses document a greater decrease in concentration of organic fatty acids, benzoic acid, phenol, 2-, 3-, 4-methylphenol, quinoline, isoquinoline, 1(2H)-quinolinone, and 2(1H)-isoquinolinone during downgradient movement in the aquifer than could be explained by dilution and/or dispersion. Laboratory microcosm studies have shown that within the study region, this effect can be attributed to microbial degradation to CH4 and CO2. A small but active methanogenic population was found on sediment materials taken from highly contaminated parts of the aquifer.

  8. Estimated natural ground-water recharge, discharge, and budget for the Dixie Valley area, west-central Nevada

    USGS Publications Warehouse

    Harrill, J.R.; Hines, L.B.

    1995-01-01

    The Dixie Valley area includes seven valleys in west-central Nevada (Dixie, Fairview, Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys; total, 2,380 square miles). Dixie Valley receives surface-water and ground-water flow from Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys and subsurface flow from Fairview Valley, which is a topographically closed basin. The relation between precipitation and altitude was re-evaluated for the Dixie Valley area using new data, and empirical estimates of recharge were revised accordingly. The revised estimate of total recharge is 23,000 acre-feet per Re-evaluation of ground-water discharge focused on Dixie Valley as the largest basin in the study area. Phreatophytic vegetation was mapped and partitioned into nine zones on the basis of species composition and foliage density. For woody phreatophytes, annual evapotranspiration rates of 0.7 cubic feet of water per cubic foot of foliage for greasewood and 1.1 cubic feet of water per cubic foot of foliage for rabbitbrush were adapted from lysimeter studies near Winnemucca, Nevada. These rates were multiplied by the foliage density of the respective phreatophytes in each zone to estimate a specific rate for that zone. Rates for salt-grass (0.5 to 0.8 foot per year) and the playa surface (0.1 to 0.3 foot per year) were based on a range of rates. used in other recent studies in western and central Nevada. These rates were multiplied by the areas of the zones to produce estimates of the annual volume of ground water discharged. The discharge estimated for Dixie Valley is between 17,000 and 28,000 acre-feet per year. The revised discharge estimate for the entire Dixie Valley area is between 20,000 and 31,000 acre-feet per year. The revised ground-water budget for the entire Dixie Valley study area has a total recharge of about 23,000 acre-feet per year. This is within the range of estimates of natural discharge--from 20,000 to 31,000 acre-feet per year. For Dixie Valley

  9. Groundwater Sustainability in the Michigan Lowlands - Understanding the Complex Interplay of Natural Brine Upwelling, Human Activity, and Climate Change

    NASA Astrophysics Data System (ADS)

    Curtis, Z. K.; Li, S. G.; Sampath, P. V.; Liao, H. S.

    2015-12-01

    /analysis to simulate the complex interplay of human activity, natural upwelling, and climate change. Insight from the modeling effort will be used to inform resource planners and policy makers of various groundwater management options available to vulnerable communities across the Lower Peninsula of Michigan in years to come.

  10. The Nature and Role of Physical Models in Enhancing Sixth Grade Students' Mental Models of Groundwater and Groundwater Processes

    ERIC Educational Resources Information Center

    Duffy, Debra Lynne Foster

    2012-01-01

    Through a non-experimental descriptive and comparative mixed-methods approach, this study investigated the experiences of sixth grade earth science students with groundwater physical models through an extended SE learning cycle format. The data collection was based on a series of quantitative and qualitative research tools intended to investigate…

  11. Natural groundwater recharge in an upland area of central North Dakota, U.S.A.

    USGS Publications Warehouse

    Rehm, B.W.; Moran, S.R.; Groenewold, G.H.

    1982-01-01

    The magnitude of groundwater recharge to coal aquifers in a 150-km2 area in west-central North Dakota was determined using three separate approaches: (1) the net water level rise in water-table wells; (2) calculations of the fluid flux between nested piezometers, using the Darcy equation and measured values of hydraulic conductivity and vertical gradients; and (3) evaluation of the inputs to and outputs from the coal aquifer, using a steady-state control volume approach in which the aquifer was divided into semi-rectangular cells bounded by equipotential lines and flow lines. Measurements of potential gradients and hydraulic conductivity permitted indirect determination of all components of flow into and out of the cell except the recharge input, which was determined by difference. All methods yielded consistent results on the order of 0.04-0.01 m yr.-1 These values, which represent 2-9% of the annual precipitation, are consistent with results of other studies on recharge throughout the prairies of North America. Evaluation of site hydrology and stable-isotope data indicates that recharge is restricted in both time and place. Most recharge occurs in late spring and in the fall following heavy rainfall events. During these seasons the ground is not frozen and vegetation is not transpiring large amounts of water. Some recharge may occur during very heavy localized summer storms, but it is not considered volumetrically significant. Major permanent depressions on the site are a source of significant recharge. In addition, the extensive area of ephemeral standing water bodies that result from snowmelt can produce significant amounts of infiltration over the entire site. ?? 1982.

  12. Iron oxidation kinetics and phosphorus immobilization at the groundwater-surface water interface

    NASA Astrophysics Data System (ADS)

    van der Grift, Bas; Rozemeijer, Joachim; Griffioen, Jasper; van der Velde, Ype

    2014-05-01

    , with Fe(II) oxidation taking place in the soil surrounding the ditch during summer and in the surface water during winter. The dynamics in Fe(II) oxidation did not affect the dissolved P concentrations. The dissolved P concentrations of the in-stream reservoirs water were an order of magnitude lower than observed in the groundwater and have no seasonal trend. Our data showed preferential binding of P during initial stage of the Fe(II) oxidation process, indicating the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at the groundwater-surface water interface is an important geochemical mechanism in the transformation of dissolved phosphate to particulate phosphate and therefore a major control on the P retention in natural waters that drain anaerobic aquifers.

  13. Cr Stable Isotopes in Snake River Plain Aquifer Groundwater: Evidence for Natural Reduction of Dissolved Cr(VI)

    SciTech Connect

    Amanda L. Raddatz; Thomas M. Johnson; Travis L. McLing

    2011-01-01

    At Idaho National Laboratory, Cr(VI) concentrations in a groundwater plume once exceeded regulatory limits in some monitoring wells but have generally decreased over time. This study used Cr stable isotope measurements to determine if part of this decrease resulted from removal of Cr(VI) via reduction to insoluble Cr(III). Although waters in the study area contain dissolved oxygen, the basalt host rock contains abundant Fe(II) and may contain reducing microenvironments or aerobic microbes that reduce Cr(VI). Insomecontaminated locations, 53Cr/52Cr ratios are close to that of the contaminant source, indicating a lack of Cr(VI) reduction. In other locations, ratios are elevated. Part of this shift may be caused by mixing with natural background Cr(VI), which is present at low concentrations but insomelocations has elevated 53Cr/52Cr.Somecontaminated wells have 53Cr/52Cr ratios greater than the maximum attainable by mixing between the inferred contaminant and the range of natural background observed in several uncontaminated wells, suggesting that Cr(VI) reduction has occurred. Definitive proof of reduction would require additional evidence. Depth profiles of 53Cr/52Cr suggest that reduction occurs immediately below the water table, where basalts are likely least weathered and most reactive, and is weak or nonexistent at greater depth.

  14. Arsenic removal from groundwater of the Chaco-Pampean plain (Argentina) using natural geological materials as adsorbents.

    PubMed

    Bundschuh, Jochen; Bhattacharya, Prosun; Sracek, Ondra; Mellano, M Fernanda; Ramírez, Antonio E; Storniolo, Angel del R; Martín, Raúl A; Cortés, Julia; Litter, Marta I; Jean, Jiin-Shuh

    2011-01-01

    Use of natural geological materials for arsenic (As) removal is an emerging solution at a household level for poor people in remote rural settlements, especially when the materials are locally available and can be collected by the local population. Their low or zero cost makes these materials very attractive compared with synthetic or commercial materials. Sometimes, this may be the only option to provide safe water to very poor settlements. Their suitability for As removal from water is mainly due to adsorption, co-precipitation and ion exchange processes involving Fe- and Al-rich minerals and clay minerals present in the soils or sediments. In the present study, various clay-rich soils from the Santiago del Estero province (SDE, NW Argentina) and, for comparison, a laterite from the Misiones province have been tested as adsorbents for As in shallow naturally contaminated groundwaters of the Río Dulce alluvial aquifer in SDE. Batch adsorption experiments showed higher As(V) removal for the Misiones laterite sample (99 %) as compared with the soils from SDE (40-53 %), which can be related to lower contents of water-soluble and oxalate extractable Al and Fe in the last samples. These results suggest the application of the Misiones laterite soil as an alternative for As removal. However, high transportation costs from Misiones to SDE can be an economical restriction for the low-income population of SDE. PMID:21879863

  15. Impact of aluminum chloride on process performance and microbial community structure of granular sludge in an upflow anaerobic sludge blanket reactor for natural rubber processing wastewater treatment.

    PubMed

    Thanh, Nguyen Thi; Watari, Takahiro; Thao, Tran Phuong; Hatamoto, Masashi; Tanikawa, Daisuke; Syutsubo, Kazuaki; Fukuda, Masao; Tan, Nguyen Minh; Anh, To Kim; Yamaguchi, Takashi; Huong, Nguyen Lan

    2016-01-01

    In this study, granular sludge formation was carried out using an aluminum chloride supplement in an upflow anaerobic sludge blanket (UASB) reactor treating natural rubber processing wastewater. Results show that during the first 75 days after the start-up of the UASB reactor with an organic loading rate (OLR) of 2.65 kg-COD·m(-3)·day(-1), it performed stably with a removal of 90% of the total chemical oxygen demand (COD) and sludge still remained in small dispersed flocs. However, after aluminum chloride was added at a concentration of 300 mg·L(-1) and the OLR range was increased up to 5.32 kg-COD·m(-3)·day(-1), the total COD removal efficiency rose to 96.5 ± 2.6%, with a methane recovery rate of 84.9 ± 13.4%, and the flocs began to form granules. Massively parallel 16S rRNA gene sequencing of the sludge retained in the UASB reactor showed that total sequence reads of Methanosaeta sp. and Methanosarcina sp., reported to be the key organisms for granulation, increased after 311 days of operation. This indicates that the microbial community structure of the retained sludge in the UASB reactor at the end of the experiment gave a good account of itself in not only COD removal, but also granule formation. PMID:27438256

  16. Development of a natural treatment system consisting of red ball earth and alfalfa for the post-treatment of anaerobically digested livestock wastewater.

    PubMed

    Chen, Xiaochen; Fukushi, Kensuke

    2014-01-01

    With the objective of developing a post-treatment process for anaerobically digested livestock wastewater, an innovative natural treatment system composed of two units is proposed. The first trickling filter unit further reduced biochemical oxygen demand and achieved a certain degree of nitrification. The second soil-plant unit was targeted at the removal and recovery of nutrients N, P and K. For the feasibility study, a bench-scale soil column test was carried out, in which red ball earth and alfalfa were utilized for treating synthetic nutrient-enriched wastewater. Through long-term operation, the nitrification function was well established in the top layers, especially the top 20 cm, although a supplementary denitrification process was still required before discharge. P and K were retained by the soil through different mechanisms, and their plant-available forms that remained in the soil were considered suitable for indirect nutrient reuse. As for alfalfa, with wastewater application it fixed more N from the atmosphere, and directly recovered 6% of P and 4% of K input from wastewater. More importantly, alfalfa was verified to have an indispensable role in stimulating the soil nitrifying microorganisms by sustaining their abundance during substrate (NH3) and oxygen scarcity, and enhancing cell-specific nitrification potential during substrate (NH3) and oxygen sufficiency. The proposed system is expected to be further improved, and adopted as a sound countermeasure for livestock wastewater pollution. PMID:25225925

  17. Development of natural treatment system consisting of black soil and Kentucky bluegrass for the post-treatment of anaerobically digested strong wastewater.

    PubMed

    Chen, Xiaochen; Fukushi, Kensuke

    2016-03-01

    To develop a sound post-treatment process for anaerobically-digested strong wastewater, a novel natural treatment system comprising two units is put forward. The first unit, a trickling filter, provides for further reduction of biochemical oxygen demand and adjustable nitrification. The subsequent soil-plant unit aims at removing and recovering the nutrients nitrogen (N), phosphorus (P) and potassium (K). As a lab-scale feasibility study, a soil column test was conducted, in which black soil and valuable Kentucky bluegrass were integrated to treat artificial nutrient-enriched wastewater. After a long-term operation, the nitrification function was well established in the top layers, despite the need for an improved denitrification process prior to discharge. P and K were retained by the soil through distinct mechanisms. Since they either partially or totally remained in plant-available forms in the soil, indirect nutrient reuse could be achieved. As for Kentucky bluegrass, it displayed better growth status when receiving wastewater, with direct recovery of 8%, 6% and 14% of input N, P and K, respectively. Furthermore, the indispensable role of Kentucky bluegrass for better treatment performance was proved, as it enhanced the cell-specific nitrification potential of the soil nitrifying microorganisms inhabiting the rhizosphere. After further upgrade, the proposed system is expected to become a new solution for strong wastewater pollution. PMID:26969049

  18. EVALUATION OF THE ROLE OF DEHALOCOCCOIDES ORGANISMS IN THE NATURAL ATTENUATION OF CHLORINATED ETHYLENES IN GROUNDWATER

    EPA Science Inventory

    At most hazardous waste sites where monitored natural attenuation (MNA) of chlorinated solvents in ground water is successful as a remedy, the chlorinated solvents are biologically degraded to harmless end products such as ethylene or ethane. Many organisms can degrade chlorinat...

  19. REMOVAL OF ARSENIC FROM GROUNDWATER USING NATURALLY OCCURRING IRON OXIDES IN RURAL REGIONS OF MONGOLIA

    EPA Science Inventory

    We have found that the iron oxide particles produced by grinding naturally occurring iron ores are very effective in removing arsenic from water. The arsenic adsorption isothermal of the particles h...

  20. An Approach for Evaluating the Progress of Natural Attenuation in Groundwater (Web Conference)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) is widely applied to ground water contamination at hazardous waste sites. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), MNA is considered to be a remedy like any other remedy. When MNA has been select...

  1. EFFECT OF ETHANOL ON THE NATURAL FERMENTATION OF BENZENE IN GROUNDWATER

    EPA Science Inventory

    Ethanol is commonly used as a fuel oxygenate in California and in the mid continent area around the Great Lakes. The presence of ethanol in a gasoline spill has raised concerns about the effects of the additive on the natural biodegradation of fuel hydrocarbons, including benzen...

  2. EFFECT OF ETHANOL ON THE NATURAL FERMENTATION OF BENZENE IN GROUNDWATER (ABSTRACT ONLY)

    EPA Science Inventory

    Ethanol is commonly used as a fuel oxygenate in California and in the mid continent area around the Great Lakes. The presence of ethanol in a gasoline spill has raised concerns about the effects of the additive on the natural biodegradation of fuel hydrocarbons, including benzen...

  3. NATURAL BIOREMEDIATION PERSPECTIVE FOR BTX CONTAMINATED GROUNDWATER IN BRAZIL: EFFECT OF ETHANOL (R823420)

    EPA Science Inventory

    Abstract

    Natural bioremediation, the use of indigenous microorganisms to degrade hazardous substances within aquifers without engineered stimulation, shows great promise as a cost-effective approach to hydrocarbon plume management. This technique requires thorough site...

  4. Using Isomap to differentiate between anthropogenic and natural effects on groundwater dynamics in a complex geological setting

    NASA Astrophysics Data System (ADS)

    Boettcher, Steven; Merz, Christoph; Lischeid, Gunnar

    2015-04-01

    control the system. The method was applied on a data set of groundwater head and lake water level. Two factors explaining more than 95 percent of the observed spatial variations were identified: (1) the anthropogenic impact of a waterworks in the study area and (2) natural groundwater recharge dynamics of different degrees of dampening at the respective sites of observation. The spatial variation of the identified processes revealed previously unknown hydraulic connections between two aquifers and between surface water bodies and groundwater. The obtained information can be used to reduce model structure uncertainty and a more efficient process-based modeling of hydraulic system behavior. Thus, the approach provides essential information to evaluate and adapt strategies for an integrated water resources management in complex landscapes. Bloschl, G., Sivapalan, M., 1995. Scale Issues in Hydrological Modeling - a Review. Hydrological Processes, 9(3-4): 251-290. Tenenbaum, J.B., de Silva, V., Langford, J.C., 2000. A global geometric framework for nonlinear dimensionality reduction. Science, 290: 2319-2323. Wood, E.F., Sivapalan, M., Beven, K., Band, L., 1988. Effects of Spatial Variability and Scale with Implications to Hydrologic Modeling. Journal of Hydrology, 102(1-4): 29-47.

  5. Groundwater capture processes under a seasonal variation in natural recharge and discharge

    NASA Astrophysics Data System (ADS)

    Maddock, Thomas, III.; Vionnet, Leticia Beatriz

    "Capture" is the increase in recharge and the decrease in discharge that occurs when pumping is imposed on an aquifer system that was in a previous state of approximate dynamic equilibrium. Regional groundwater models are usually used to calculate capture in a two-step procedure. A steady-state solution provides an initial-head configuration, a set of flows through the boundaries for the modeled region, and the initial basis for the capture calculation. The transient solutions provide the total change in flows through the boundaries. A difference between the transient and steady-state solutions renders the capture calculation. When seasonality is a modeling issue, the use of a single initial hydraulic head and a single set of boundary flows leads to miscalculations of capture. Instead, an initial condition for each season should be used. This approach may be accomplished by determining steady oscillatory solutions, which vary through the seasons but repeat from year to year. A regional groundwater model previously developed for a portion of the San Pedro River basin, Arizona, USA, is modified to illustrate the effect that different initial conditions have on transient solutions and on capture calculations. Résumé Les "prélèvements" sont constitués par l'augmentation de la recharge et par la diminution de l'écoulement qui se produit lorsqu'un pompage est imposéà un système aquifère qui était auparavant dans un état proche de l'équilibre dynamique. Les modèles régionaux de nappe sont en général utilisés pour calculer les prélèvements dans une procédure à deux étapes. Une solution en régime permanent donne la configuration piézométrique initiale, un jeu de conditions aux limites pour la région modélisée et les données de base pour le calcul des prélèvements. Les solutions transitoires donnent les modifications globales des conditions aux limites. Lorsque des variations saisonnières sont produites en sortie du modèle, le recours à une

  6. Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Carnegie, John W., Ed.

    This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

  7. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Estimated Mean Annual Natural Groundwater Recharge, 2002

    USGS Publications Warehouse

    Wieczorek, Michael E.; LaMotte, Andrew E.

    2010-01-01

    This data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every catchment of NHDPlus for the conterminous United States. The source data set is Estimated Mean Annual Natural Ground-Water Recharge in the Conterminous United States (Wolock, 2003). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, containing NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the

  8. Disequilibrium study of natural radionuclides of uranium and thorium series in cores and briny groundwaters from Palo Duro Basin, Texas

    SciTech Connect

    Laul, J.C.; Smith, M.R.

    1988-05-01

    The concentrations of natural radionuclides of the /sup 238/U and /232/Th series are reported in several cores and in ten deep and five shallow briny groundwaters from various formations in the Palo Duro Basin. The formations include Granite Wash, Pennsylvanian Granite Wash, Wolfcamp Carbonate, Pennsylvanian Carbonate, Seven River, Queen Grayburg, San Andres, Yates and Salado. The natural radionuclide data in cores suggest that the radionuclides have not migrated or been leached for at least a period of about 1 million years. Relative to the U and Th concentrations in cores, the brines are depleted by a factor of 10/sup 4/ to 10/sup 5/, indicating extremely low solubility of U and Th in brines. The natural radionuclide data in brines suggest that radium is not sorbed significantly and thus not retarded in nine deep brines. Radium is somewhat sorbed in one deep brine of Wolfcamp Carbonate and significantly sorbed in shallow brines. Relative to radium, the U, Th, Pb, Bi, and Po radionuclides are highly retarded by sorption. The retardation factors for /sup 228/Th range from 10/sup 2/ to 10/sup 3/, whereas those for /sup 230/Th and /sup 234/U range from 10/sup 3/ to 10/sup 5/, depending on the formation. The /sup 234/U//sup 238/U ratios in these brines are constant at about 1.5. The magnitude of the /sup 234/U//sup 230/Th ratio appears to reflect the degree of redox state of the aquifer's environment. The /sup 234/U//sup 230/Th ratio in nine deep brines is about unity, suggesting that U, like Th/sup +4/, is in the +4 state, which in turn suggests a reduced environment. 49 refs., 23 figs., 18 tabs.

  9. Cr(VI)-contaminated groundwater remediation with simulated permeable reactive barrier (PRB) filled with natural pyrite as reactive material: Environmental factors and effectiveness.

    PubMed

    Liu, Yuanyuan; Mou, Haiyan; Chen, Liqun; Mirza, Zakaria A; Liu, Li

    2015-11-15

    Permeable reactive barriers (PRBs) are efficient technologies for in situ remediation of contaminated groundwater, the effectiveness of which greatly depends on the reactive media filled. Natural pyrite is an iron sulfide material with a very low content of iron and sulfur, and a mining waste which is a potential material for Cr(VI) immobilization. In this study, we conducted a series of batch tests to research the effects of typical environmental factors on Cr(VI) removal and also simulated PRB filled with natural pyrite to investigate its effectiveness, in order to find a both environmentally and economically fine method for groundwater remediation. Batch tests showed that pH had the significant impact on Cr(VI) removal with an apparently higher efficiency under acidic conditions, and dissolved oxygen (DO) would inhibit Cr(VI) reduction; a relatively high initial Cr(VI) concentration would decrease the rate of Cr(VI) sorption; ionic strength and natural organic matter resulted in no significant effects on Cr(VI) removal. Column tests demonstrated that the simulated PRB with natural pyrite as the reactive media was considerably effective for removing Cr(VI) from groundwater, with a sorption capability of 0.6222 mg Cr per gram of natural pyrite at an initial Cr(VI) concentration of 10mg/L at pH 5.5 in an anoxic environment. PMID:26026959

  10. Dissolved gas composition of groundwater in the natural spa complex "Choygan mineral waters" (East Tuva)

    NASA Astrophysics Data System (ADS)

    Kopylova, Y.; Guseva, N.; Shestakova, A.; Khvaschevskaya, A.; Arakchaa, K.

    2014-08-01

    The natural spa complex "Choygan mineral waters", a unique deposit of natural carbon dioxide mineral waters in Siberia, is located in the Eastern Sayan Mountains. There are 33 springs discharge in this area. Spring waters are mainly HCO3-Na-Ca type. TDS varies from 300 mg/L to 2600 mg/L and temperature ranges from 7 °C (in spring 33) to 39 °C (in spring 12), pH varies from 5.9 to 8.3, and the value of the oxidation-reduction potential is from - 170 mV to 236 mV. All studied waters were divided into two groups according to their temperature and geochemical conditions: cold fresh water with oxidizing conditions and warm slightly brackish water with reductive conditions. The gas composition of the studied waters is represented by nitrogen (28-75 vol.%), carbon dioxide (6-65 vol.%), oxygen (7-19 vol.%), radon (4-948 Bq/l). The studied gases differ not only by the content but by the different sources.

  11. Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

    USGS Publications Warehouse

    Ayotte, J.D.; Szabo, Z.; Focazio, M.J.; Eberts, S.M.

    2011-01-01

    The effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes and artificial connection of aquifers by well screens can mix chemically distinct groundwater. Chemical reactions between these mixed groundwaters and solid aquifer materials can result in the mobilization of trace elements such as U, As and Ra, with subsequent transport to water-supply wells. For example, in the High Plains aquifer near York, Nebraska, mixing of shallow, oxygenated, lower-pH water from an unconfined aquifer with deeper, confined, anoxic, higher-pH water is facilitated by wells screened across both aquifers. The resulting higher-O2, lower-pH mixed groundwater facilitated the mobilization of U from solid aquifer materials, and dissolved U concentrations were observed to increase significantly in nearby supply wells. Similar instances of trace element mobilization due to human-induced mixing of groundwaters were documented in: (1) the Floridan aquifer system near Tampa, Florida (As and U), (2) Paleozoic sedimentary aquifers in eastern Wisconsin (As), (3) the basin-fill aquifer underlying the California Central Valley near Modesto (U), and (4) Coastal Plain aquifers of New Jersey (Ra). Adverse water-quality impacts attributed to human activities are commonly assumed to be related solely to the release of the various anthropogenic contaminants to the environment. The results show that human activities including various land uses, well drilling, and pumping rates and volumes can adversely impact the quality of water in supply wells, when associated with naturally-occurring trace elements in aquifer materials. This occurs by causing subtle but significant changes in

  12. The impact of CO2 on shallow groundwater chemistry: observations at a natural analog site and implications for carbon sequestration

    SciTech Connect

    Keating, Elizabeth; Fessenden, Julianna; Kanjorski, Nancy; Koning, Dan; Pawar, Rajesh

    2008-01-01

    In a natural analog study of risks associated with carbon sequestration, impacts of CO{sub 2} on shallow groundwater quality have been measured in a sandstone aquifer in New Mexico, USA. Despite relatively high levels of dissolved CO{sub 2}, originating from depth and producing geysering at one well, pH depression and consequent trace element mobility are relatively minor effects due to the buffering capacity of the aquifer. However, local contamination due to influx of saline waters in a subset of wells is significant. Geochemical modeling of major ion concentrations suggests that high alkalinity and carbonate mineral dissolution buffers pH changes due to CO{sub 2} influx. Analysis oftrends in dissolved trace elements, chloride, and CO2 reveal no evidence of in-situ trace element mobilization. There is clear evidence, however, that As, U, and Pb are locally co-transported into the aquifer with CO{sub 2}-rich saline water. This study illustrates the role that local geochemical conditions will play in determining the effectiveness of monitoring strategies for CO{sub 2} leakage. For example, if buffering is significant, pH monitoring may not effectively detect CO2 leakage. This study also highlights potential complications that CO{sub 2}carrier fluids, such as saline waters, pose in monitoring impacts ofgeologic sequestration.

  13. CHARACTERIZATION AND MONITORING OF NATURAL ATTENUATION OF CHLORINATED SOLVENTS IN GROUNDWATER: A SYSTEMS APPROACH

    SciTech Connect

    Looney, B; Michael Heitkamp, M; Gary Wein , G; Christopher Bagwell, C; Karen Vangelas, K; Karen-M Adams, K; Tyler Gilmore; Norman Cutshall; David Major; Mike Truex; Todd Wiedemeier; Francis H. Chapelle; Tom Early; Jody Waugh; David Peterson; Mark Ankeny; Claire H. Sink

    2006-08-10

    The objective of this document is to examine the use of a phased approach to characterizing and monitoring (C&M) natural attenuation processes and enhanced attenuation processes and to identify promising tools and techniques by which to accomplish the C&M. We will investigate developing techniques, such as molecular-based assessment tools, and existing tools that traditionally have not been used for monitoring the performance of environmental remediation technologies. Case studies will be used to provide examples of how non-traditional methods are being employed as characterization and monitoring tools to support MNA and EA. The document is not focused on a specific group of readers but rather is broadly directed with the intent that readers may gain information useful to their purposes. Thus, regulators may see some future characterization and monitoring techniques; end users may find novel ways to make MNA or EA more effective or efficient at their site; researchers may identify new areas for development or new and better combinations of existing methods. One consequence of this broad approach is that some readers may find certain sections either too rudimentary or too advanced for their needs. Hopefully, all will be able to use at least some of the document.

  14. Microbial diversity and dynamics of a groundwater and a still bottled natural mineral water.

    PubMed

    França, Luís; Lopéz-Lopéz, Arantxa; Rosselló-Móra, Ramon; da Costa, Milton S

    2015-03-01

    The microbial abundance and diversity at source, after bottling and through 6 months of storage of a commercial still natural mineral water were assessed by culture-dependent and culture-independent methods. The results revealed clear shifts of the dominant communities present in the three different stages. The borehole waters displayed low cell densities that increased 1.5-fold upon bottling and storage, reaching a maximum (6.2 × 10(8)  cells l(-1) ) within 15 days after bottling, but experienced a significant decrease in diversity. In all cases, communities were largely dominated by Bacteria. The culturable heterotrophic community was characterized by recovering 3626 isolates, which were primarily affiliated with the Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. This study indicates that bottling and storage induce quantitative and qualitative changes in the microbial assemblages that seem to be similar as revealed by the two sample batches collected on 2 consecutive years. To our knowledge, this is the first study combining culture-independent with culture-dependent methods, and repeated tests to reveal the microbial dynamics occurring from source to stored bottled water. PMID:24612305

  15. BIOVENTING - Groundwater Aeration by Discontinuous Oxygen Gas Pulse Injections

    NASA Astrophysics Data System (ADS)

    Schirmer, M.

    2003-12-01

    Groundwater aeration by discontinuous oxygen gas pulse injections appears to be a promising concept for enhanced natural attenuation of dissolved contaminants that are susceptible for oxygenase enzyme attacks. Oxygen amendments facilitate indigenous microbiota to catabolize groundwater pollutants, such as aromatics, that are considered to be recalcitrant in absence of dissolved oxygen. As a rule, natural attenuation of many pollutants under aerobic conditions is considerably faster than under anaerobic conditions. Thus, enhancing the dissolved oxygen level appears to be worthwhile. In situ aeration of groundwater has been accomplished by air sparging, H2O2-supply, or by utilization of oxygen release compounds. However, continuous aeration of previously anaerobic groundwater is not desirable for several reasons: (a) economic efforts too high, (b) pollutant dislocation towards surface (desired only in air sparging), (c) risk of aquifer clogging (gas clogging, oxidation of ferrous iron, formation of bioslimes). In contrast, discontinuous oxygen gas sparging provides only for periodical groundwater aeration which is followed by microaerobic and suboxic conditions. Microaerobic conditions can prevail spatially (e.g., at plume fringes or within biofilms) or temporarily (e.g., at discontinuous bioventing). They still allow adapted bacteria to transform environmental pollutants to less toxic compounds, e.g., aromatic ring cleavage after dioxygenasis attack. Ring cleavage products, on the other hand, may be degraded more easily by anaerobic consortia than the initial aromatic compounds, making oxygen depletion periods highly intriguing in regard to an initiation of natural attenuation processes at plume fringes. In our work we outline the effect of oxygen depletion conditions on biodegradation of monchlorobenzene (MCB) as they occur subsequently to temporary aeration periods. For microaerobic conditions, relative to the oxygen supply, a stoichiometric transformation of MCB

  16. Nitrogen-isotope analysis of groundwater nitrate in carbonate aquifers: Natural sources versus human pollution

    NASA Astrophysics Data System (ADS)

    Kreitler, Charles W.; Browning, Lawrence A.

    1983-02-01

    Results of nitrogen-isotope analyses of nitrate in the waters of the Cretaceous Edwards aquifer in Texas, U.S.A., indicate that the source of the nitrate is naturally-occurring nitrogen compounds in the recharge streams. In contrast, nitrogen isotopes of nitrate in the fresh waters of the Pleistocene Ironshore Formation on Grand Cayman Island, West Indies, indicate that human wastes are the source of the nitrate. The Cretaceous Edwards Limestone is a prolific aquifer that produces principally from fracture porosity along the Balcones Fault Zone. Recharge is primarily by streams crossing the fault zone. Rainfall is ˜ 70 cm yr. -1, and the water table is generally deeper than 30 m below land surface. The δ15 N of 73 samples of nitrate from Edwards waters ranged from + 1.9 to + 10‰ with an average of + 6.2‰. This δ15 N range is within the range of nitrate in surface water in the recharge streams ( δ 15N range = + 1 to + 8.3‰ ) and within the range of nitrate in surface water from the Colorado River, Texas, ( δ 15N range = + 1 to + 11‰ ). No sample was found to be enriched in 15N, which would suggest the presence of nitrate from animal waste ( δ 15N range = + 10 to + 22‰ ). The Ironshore Formation contains a small freshwater lens that is recharged entirely by percolation through the soil. Average rainfall is 165 cm yr. -1, and the water table is within 3 m of land surface. The δ15 N of four nitrate samples from water samples of the Ironshore Formation ranged from + 18 to + 23.9‰, which indicates a cesspool/septictank source of the nitrate. Limestone aquifers in humid environments that are recharged by percolation through the soil appear to be more susceptible to contamination by septic tanks than are aquifers in subhumid environments that feature thick unsaturated sections and are recharged by streams.

  17. Effects of natural and human factors on groundwater quality of basin-fill aquifers in the southwestern United States-conceptual models for selected contaminants

    USGS Publications Warehouse

    Bexfield, Laura M.; Thiros, Susan A.; Anning, David W.; Huntington, Jena M.; McKinney, Tim S.

    2011-01-01

    As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, the Southwest Principal Aquifers (SWPA) study is building a better understanding of the factors that affect water quality in basin-fill aquifers in the Southwestern United States. The SWPA study area includes four principal aquifers of the United States: the Basin and Range basin-fill aquifers in California, Nevada, Utah, and Arizona; the Rio Grande aquifer system in New Mexico and Colorado; and the California Coastal Basin and Central Valley aquifer systems in California. Similarities in the hydrogeology, land- and water-use practices, and water-quality issues for alluvial basins within the study area allow for regional analysis through synthesis of the baseline knowledge of groundwater-quality conditions in basins previously studied by the NAWQA Program. Resulting improvements in the understanding of the sources, movement, and fate of contaminants are assisting in the development of tools used to assess aquifer susceptibility and vulnerability. This report synthesizes previously published information about the groundwater systems and water quality of 15 information-rich basin-fill aquifers (SWPA case-study basins) into conceptual models of the primary natural and human factors commonly affecting groundwater quality with respect to selected contaminants, thereby helping to build a regional understanding of the susceptibility and vulnerability of basin-fill aquifers to those contaminants. Four relatively common contaminants (dissolved solids, nitrate, arsenic, and uranium) and two contaminant classes (volatile organic compounds (VOCs) and pesticide compounds) were investigated for sources and controls affecting their occurrence and distribution above specified levels of concern in groundwater of the case-study basins. Conceptual models of factors that are important to aquifer vulnerability with respect to those contaminants and contaminant classes were subsequently formed. The

  18. Spectrum and treatment of anaerobic infections.

    PubMed

    Brook, Itzhak

    2016-01-01

    Anaerobes are the most predominant components of the normal human skin and mucous membranes bacterial flora, and are a frequent cause of endogenous bacterial infections. Anaerobic infections can occur in all body locations: the central nervous system, oral cavity, head and neck, chest, abdomen, pelvis, skin, and soft tissues. Treatment of anaerobic infection is complicated by their slow growth in culture, by their polymicrobial nature and by their growing resistance to antimicrobials. Antimicrobial therapy is frequently the only form of therapy needed, whereas in others it is an important adjunct to drainage and surgery. Because anaerobes generally are isolated mixed with aerobes, the antimicrobial chosen should provide for adequate coverage of both. The most effective antimicrobials against anaerobes are: metronidazole, the carbapenems (imipenem, meropenem, doripenem, ertapenem), chloramphenicol, the combinations of a penicillin and a beta-lactamase inhibitors (ampicillin or ticarcillin plus clavulanate, amoxicillin plus sulbactam, piperacillin plus tazobactam), tigecycline, cefoxitin and clindamycin. PMID:26620376

  19. Groundwater-fed irrigation impacts spatially distributed temporal scaling behavior of the natural system: a spatio-temporal framework for understanding water management impacts

    NASA Astrophysics Data System (ADS)

    Condon, Laura E.; Maxwell, Reed M.

    2014-03-01

    Regional scale water management analysis increasingly relies on integrated modeling tools. Much recent work has focused on groundwater-surface water interactions and feedbacks. However, to our knowledge, no study has explicitly considered impacts of management operations on the temporal dynamics of the natural system. Here, we simulate twenty years of hourly moisture dependent, groundwater-fed irrigation using a three-dimensional, fully integrated, hydrologic model (ParFlow-CLM). Results highlight interconnections between irrigation demand, groundwater oscillation frequency and latent heat flux variability not previously demonstrated. Additionally, the three-dimensional model used allows for novel consideration of spatial patterns in temporal dynamics. Latent heat flux and water table depth both display spatial organization in temporal scaling, an important finding given the spatial homogeneity and weak scaling observed in atmospheric forcings. Pumping and irrigation amplify high frequency (sub-annual) variability while attenuating low frequency (inter-annual) variability. Irrigation also intensifies scaling within irrigated areas, essentially increasing temporal memory in both the surface and the subsurface. These findings demonstrate management impacts that extend beyond traditional water balance considerations to the fundamental behavior of the system itself. This is an important step to better understanding groundwater’s role as a buffer for natural variability and the impact that water management has on this capacity.

  20. Hydrogeologic Settings and Ground-Water Flow Simulations for Regional Studies of the Transport of Anthropogenic and Natural Contaminants to Public-Supply Wells - Studies Begun in 2001

    USGS Publications Warehouse

    Paschke, Suzanne S., (Edited By)

    2007-01-01

    This study of the Transport of Anthropogenic and Natural Contaminants to public-supply wells (TANC study) is being conducted as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program and was designed to increase understanding of the most important factors to consider in ground-water vulnerability assessments. The seven TANC studies that began in 2001 used retrospective data and ground-water flow models to evaluate hydrogeologic variables that affect aquifer susceptibility and vulnerability at a regional scale. Ground-water flow characteristics, regional water budgets, pumping-well information, and water-quality data were compiled from existing data and used to develop conceptual models of ground-water conditions for each study area. Steady-state regional ground-water flow models were used to represent the conceptual models, and advective particle-tracking simulations were used to compute areas contributing recharge and traveltimes from recharge to selected public-supply wells. Retrospective data and modeling results were tabulated into a relational database for future analysis. Seven study areas were selected to evaluate a range of hydrogeologic settings and management practices across the Nation: the Salt Lake Valley, Utah; the Eagle Valley and Spanish Springs Valley, Nevada; the San Joaquin Valley, California; the Northern Tampa Bay region, Florida; the Pomperaug River Basin, Connecticut; the Great Miami River Basin, Ohio; and the Eastern High Plains, Nebraska. This Professional Paper Chapter presents the hydrogeologic settings and documents the ground-water flow models for each of the NAWQA TANC regional study areas that began work in 2001. Methods used to compile retrospective data, determine contributing areas of public-supply wells, and characterize oxidation-reduction (redox) conditions also are presented. This Professional Paper Chapter provides the foundation for future susceptibility and vulnerability analyses in the TANC

  1. Mechanisms of Virus Adsorption Following Land Application of Anaerobically Treated Flushed Dairy Manure Wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The soil adsorption mechanisms of viruses in untreated and anaerobically treated animal manure wastewater and groundwater was investigated. Batch adsorption studies were performed using cationic (hexadecyltrimethylammonium bromide, HTAB), anionic (sodium dodecyl sulfate, SDS), and nonionic (polyoxy...

  2. Evaluation of Groundwater Recharge Estimates in a Partially Metamorphosed Sedimentary Basin in a Tropical Environment: Application of Natural Tracers

    PubMed Central

    Oteng Mensah, Felix; Alo, Clement

    2014-01-01

    This study tests the representativeness of groundwater recharge estimates through the chloride mass balance (CMB) method in a tropical environment. The representativeness of recharge estimates using this methodology is tested using evaporation estimates from isotope data, the general spatial distribution of the potential field, and the topographical variations in the area. This study suggests that annual groundwater recharge rates in the area ranges between 0.9% and 21% of annual precipitation. These estimates are consistent with evaporation rates computed from stable isotope data of groundwater and surface water in the Voltaian Basin. Moreover, estimates of groundwater recharge through numerical model calibration in other parts of the terrain appear to be consistent with the current data in this study. A spatial distribution of groundwater recharge in the area based on the estimated data takes a pattern akin to the spatial pattern of distribution of the hydraulic head, the local topography, and geology of the terrain. This suggests that the estimates at least qualitatively predicts the local recharge and discharge locations in the terrain. PMID:24772021

  3. Distinct carbon isotope fractionation during anaerobic degradation of dichlorobenzene isomers.

    PubMed

    Liang, Xiaoming; Mundle, Scott O C; Nelson, Jennifer L; Passeport, Elodie; Chan, Calvin C H; Lacrampe-Couloume, Georges; Zinder, Stephen H; Sherwood Lollar, Barbara

    2014-05-01

    Chlorinated benzenes are ubiquitous organic contaminants found in groundwater and soils. Compound specific isotope analysis (CSIA) has been increasingly used to assess natural attenuation of chlorinated contaminants, in which anaerobic reductive dechlorination plays an essential role. In this work, carbon isotope fractionation of the three dichlorobenzene (DCB) isomers was investigated during anaerobic reductive dehalogenation in methanogenic laboratory microcosms. Large isotope fractionation of 1,3-DCB and 1,4-DCB was observed while only a small isotope effect occurred for 1,2-DCB. Bulk enrichment factors (εbulk) were determined from a Rayleigh model: -0.8 ± 0.1 ‰ for 1,2-DCB, -5.4 ± 0.4 ‰ for 1,3-DCB, and -6.3 ± 0.2 ‰ for 1,4-DCB. εbulk values were converted to apparent kinetic isotope effects for carbon (AKIE) in order to characterize the carbon isotope effect at the reactive positions for the DCB isomers. AKIE values are 1.005 ± 0.001, 1.034 ± 0.003, and 1.039 ± 0.001 for 1,2-DCB, 1,3-DCB, and 1,4-DCB, respectively. The large difference in AKIE values between 1,2-DCB and 1,3-DCB (or 1,4-DCB) suggests distinct reaction pathways may be involved for different DCB isomers during microbial reductive dechlorination by the methanogenic cultures. PMID:24758692

  4. Groundwater contamination in coastal urban areas: Anthropogenic pressure and natural attenuation processes. Example of Recife (PE State, NE Brazil)

    NASA Astrophysics Data System (ADS)

    Bertrand, G.; Hirata, R.; Pauwels, H.; Cary, L.; Petelet-Giraud, E.; Chatton, E.; Aquilina, L.; Labasque, T.; Martins, V.; Montenegro, S.; Batista, J.; Aurouet, A.; Santos, J.; Bertolo, R.; Picot, G.; Franzen, M.; Hochreutener, R.; Braibant, G.

    2016-09-01

    In a context of increasing land use pressure (over-exploitation, surface-water contamination) and repeated droughts, identifying the processes affecting groundwater quality in coastal megacities of the tropical and arid countries will condition their long-term social and environmental sustainability. The present study focuses on the Brazilian Recife Metropolitan Region (RMR), which is a highly urbanized area (3,743,854 inhabitants in 2010) on the Atlantic coast located next to an estuarial zone and overlying a multi-layered sedimentary system featured by a variable sediment texture and organic content. It investigates the contamination and redox status patterns conditioning potential attenuation within the shallow aquifers that constitute the interface between the city and the strategic deeper semi-confined aquifers. These latter are increasingly exploited, leading to high drawdown in potenciometric levels of 20-30 m and up to 70 m in some high well density places, and potentially connected to the surface through leakage. From a multi-tracer approach (major ions, major gases, δ11B, δ18O-SO4, δ34S-SO4) carried out during two field campaigns in September 2012 and March 2013 (sampling of 19 wells and 3 surface waters), it has been possible to assess the contamination sources and the redox processes. The increasing trend for mineralization from inland to coastal and estuarial wells (from 119 to around 10,000 μS/cm) is at first attributed to water-rock interactions combined with natural and human-induced potentiometric gradients. Secondly, along with this trend, one finds an environmental pressure gradient related to sewage and/or surface-channel network impacts (typically depleted δ11B within the range of 10-15‰) that are purveyors of chloride, nitrate, ammonium and sulfate. Nitrate, ammonium and sulfate (ranging from 0 to 1.70 mmol/L, from 0 to 0,65 mmol/L, from 0.03 to 3.91 mmol/L respectively are also potentially produced or consumed through various redox

  5. Assessing Spatial Patterns of Lake-Groundwater Exchange Using Distributed Temperature Sensing (DTS) and Heat as a Natural Tracer

    NASA Astrophysics Data System (ADS)

    Fleckenstein, J. H.; Neumann, C.; Hausner, M. B.; Tyler, S. W.; Angermann, L.; Lewandowski, J.

    2011-12-01

    Heat as a natural tracer is commonly used to evaluate groundwater (GW) surface water (SW) interactions in the field. Seasonal temperature differences between GW and SW can be used to qualitatively map areas of preferential exchange. Under certain assumptions analytical solutions to the heat transport equations allow a simple quantification of exchange fluxes by an inversion of advective heat flux from temperature distributions. To reliably map temperature anomalies at the GW-SW interface in snapshot measurements using conventional temperature sensors or to quantitatively separate heat transport by advection from heat conduction typically requires a sufficient magnitude of advective flow (> 10-6 m/s). Exchange fluxes in that range are commonly encountered in stream-aquifer systems, where streambed materials are coarse and vertical hydraulic gradients relatively large. In contrast exchange fluxes between lakes and GW can be much smaller (< 10-8 m/s) due to the finer lake sediments and smaller hydraulic gradients. Also roaming temperature surveys to detect spatial patterns of exchange, as frequently used in smaller streams and rivers, are more difficult to conduct in lakes, which restricts the use of heat as a tracer in these environments. Fiber-optics based distributed temperature sensing (DTS) provides a methodology that can overcome some of these restrictions. DTS can very accurately measure temperatures at high spatial and temporal resolution and the sensor (a fiber-optic cable) can be deployed in lakes with relative ease. Important information on lake-GW exchange, which would be missed in conventional snapshot surveys of temperature, can be inferred from the temporal evolution of temperature at the water-sediment interface and from statistic of the temperature time series. Results from two DTS campaigns (one in the summer of 2008 and one in the winter of 2010) in an acid mine lake in eastern Germany are used to demonstrate the utility of DTS to characterize

  6. Groundwater contamination in coastal urban areas: Anthropogenic pressure and natural attenuation processes. Example of Recife (PE State, NE Brazil).

    PubMed

    Bertrand, G; Hirata, R; Pauwels, H; Cary, L; Petelet-Giraud, E; Chatton, E; Aquilina, L; Labasque, T; Martins, V; Montenegro, S; Batista, J; Aurouet, A; Santos, J; Bertolo, R; Picot, G; Franzen, M; Hochreutener, R; Braibant, G

    2016-09-01

    In a context of increasing land use pressure (over-exploitation, surface-water contamination) and repeated droughts, identifying the processes affecting groundwater quality in coastal megacities of the tropical and arid countries will condition their long-term social and environmental sustainability. The present study focuses on the Brazilian Recife Metropolitan Region (RMR), which is a highly urbanized area (3,743,854 inhabitants in 2010) on the Atlantic coast located next to an estuarial zone and overlying a multi-layered sedimentary system featured by a variable sediment texture and organic content. It investigates the contamination and redox status patterns conditioning potential attenuation within the shallow aquifers that constitute the interface between the city and the strategic deeper semi-confined aquifers. These latter are increasingly exploited, leading to high drawdown in potenciometric levels of 20-30m and up to 70m in some high well density places, and potentially connected to the surface through leakage. From a multi-tracer approach (major ions, major gases, δ(11)B, δ(18)O-SO4, δ(34)S-SO4) carried out during two field campaigns in September 2012 and March 2013 (sampling of 19 wells and 3 surface waters), it has been possible to assess the contamination sources and the redox processes. The increasing trend for mineralization from inland to coastal and estuarial wells (from 119 to around 10,000μS/cm) is at first attributed to water-rock interactions combined with natural and human-induced potentiometric gradients. Secondly, along with this trend, one finds an environmental pressure gradient related to sewage and/or surface-channel network impacts (typically depleted δ(11)B within the range of 10-15‰) that are purveyors of chloride, nitrate, ammonium and sulfate. Nitrate, ammonium and sulfate (ranging from 0 to 1.70mmol/L, from 0 to 0,65mmol/L, from 0.03 to 3.91mmol/L respectively are also potentially produced or consumed through various redox

  7. Assessment of groundwater input and water quality changes impacting natural vegetation in the Loxahatchee River and floodplain ecosystem, Florida

    USGS Publications Warehouse

    Orem, William H.; Swarzenski, Peter W.; McPherson, Benjamin F.; Hedgepath, Marion; Lerch, Harry E.; Reich, Christopher; Torres, Arturo E.; Corum, Margo D.; Roberts, Richard E.

    2007-01-01

    The Loxahatchee River and Estuary are small, shallow, water bodies located in southeastern Florida. Historically, the Northwest Branch (Fork) of the Loxahatchee River was primarily a freshwater system. In 1947, the river inlet at Jupiter was dredged for navigation and has remained permanently open since that time. Drainage patterns within the basin have also been altered significantly due to land development, road construction (e.g., Florida Turnpike), and construction of the C-18 and other canals. These anthropogenic activities along with sea level rise have resulted in significant adverse impacts on the ecosystem over the last several decades, including increased saltwater encroachment and undesired vegetation changes in the floodplain. The problem of saltwater intrusion and vegetation degradation in the Loxahatchee River may be partly induced by diminished freshwater input, from both surface water and ground water into the River system. The overall objective of this project was to assess the seasonal surface water and groundwater interaction and the influence of the biogeochemical characteristics of shallow groundwater and porewater on vegetation health in the Loxahatchee floodplain. The hypothesis tested are: (1) groundwater influx constitutes a significant component of the overall flow of water into the Loxahatchee River; (2) salinity and other chemical constituents in shallow groundwater and porewater of the river floodplain may affect the distribution and health of the floodplain vegetation.

  8. Assessment of natural attenuation of ground-water contamination at sites FT03, LF13, and WP14/LF15, Dover Air Force Base, Delaware

    USGS Publications Warehouse

    Barbaro, Jeffrey R.

    2002-01-01

    Water-quality, aquifer-sediment, and hydro-logic data were used to assess the effectiveness of natural attenuation of ground-water contamination at Fire Training Area Three, the Rubble Area Landfill, the Liquid Waste Disposal Landfill, and the Receiver Station Landfill in the East Management Unit of Dover Air Force Base, Delaware. These sites, which are contaminated with chlorinated solvents and fuel hydrocarbons, are under-going long-term monitoring to determine if natural attenuation continues to sufficiently reduce contaminant concentrations to meet regulatory requirements. This report is the first assessment of the effectiveness of natural attenuation at these sites since long-term monitoring began in 1999, and follows a preliminary investigation done in 1995?96. This assessment was done by the U.S. Geological Survey in cooperation with the U.S. Air Force.Since 1995?96, additional information has been collected and used in the current assessment. The conclusions in this report are based primarily on ground-water samples collected from January through March 2000. Previous analytical results from selected wells, available geologic and geo-physical well logs, and newly acquired information such as sediment organic-carbon measurements, hydraulic-conductivity measurements determined from slug tests on wells in the natural attenuation study area, and water-level measurements from surficial-aquifer wells also were used in this assessment. This information was used to: (1) calculate retardation factors and estimate contaminant migration velocities, (2) improve estimates of ground-water flow directions and inferred contaminant migration pathways, (3) better define the areal extent of contamination and the proximity of contaminants to discharge areas and the Base boundary, (4) develop a better under-standing of the vertical variability of contaminant concentrations and redox conditions, (5) evaluate the effects of temporal changes on concentrations in the plumes and

  9. Hydrogeologic settings and groundwater-flow simulations for regional investigations of the transport of anthropogenic and natural contaminants to public-supply wells—Investigations begun in 2004

    USGS Publications Warehouse

    Eberts, Sandra M.

    2011-01-01

    A study of the Transport of Anthropogenic and Natural Contaminants to public-supply wells (TANC study) was begun in 2001 as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. The study was designed to shed light on factors that affect the vulnerability of groundwater and, more specifically, water from public-supply wells to contamination to provide a context for the NAWQA Program's earlier finding of mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation. The TANC study has included investigations at both the regional (tens to thousands of square kilometers) and local (generally less than 25 square kilometers) scales. At the regional scale, the approach to investigation involves refining conceptual models of groundwater flow in hydrologically distinct settings and then constructing or updating a groundwater-flow model with particle tracking for each setting to help quantify regional water budgets, public-supply well contributing areas (areas contributing recharge to wells and zones of contribution for wells), and traveltimes from recharge areas to selected wells. A great deal of information about each contributing area is captured from the model output, including values for 170 variables that describe physical and (or) geochemical characteristics of the contributing areas. The information is subsequently stored in a relational database. Retrospective water-quality data from monitoring, domestic, and many of the public-supply wells, as well as data from newly collected samples at selected public-supply wells, also are stored in the database and are used with the model output to help discern the more important factors affecting vulnerability in many, if not most, settings. The study began with investigations in seven regional areas, and it benefits from being conducted as part of the NAWQA Program, in which consistent methods are used so that meaningful comparisons can be

  10. The role of ground-water recharge processes in the formation of natural acid-rock drainage in mineralized mountain watersheds

    NASA Astrophysics Data System (ADS)

    Manning, A. H.; Bove, D. J.; Verplanck, P. L.

    2009-12-01

    An understanding of the natural production of low-pH and metal-rich ground and surface water (acid-rock drainage, or ARD) in mineralized watersheds is important for establishing pre-mining conditions in mined locations and for evaluating the potential environmental impacts of future mining in unmined locations. The significance of hydrothermal alteration type and lithology and in ARD production is well established, but the role played by climatic factors remains poorly understood. Ground-water recharge processes (e.g., water table depth, seasonal recharge fluctuations, and unsaturated zone residence time) could exert a major influence because they control features of the unsaturated zone that should in turn directly control the oxidation of sulfide minerals in the subsurface. We are exploring the relative importance of different aspects of ground-water recharge in ARD production by performing a series of numerical geochemical modeling experiments with PHREEQC and examining recently collected geochemical and hydrologic data from Handcart Gulch, a mineralized mountain watershed in the Colorado Front Range. Preliminary results suggest that ground-water residence time in the unsaturated zone is of primary importance. However, sulfide oxidation is probably oxygen-limited in deeper unsaturated zones under mountain ridges, meaning that ARD production may be commonly limited by rates of downward oxygen diffusion. Results of this study should assist in predicting possible future changes in ARD production in mountain watersheds under anticipated climate change scenarios.

  11. Tracking natural and anthropogenic origins of dissolved arsenic during surface and groundwater interaction in a post-closure mining context: Isotopic constraints

    NASA Astrophysics Data System (ADS)

    Khaska, Mahmoud; Le Gal La Salle, Corinne; Verdoux, Patrick; Boutin, René

    2015-06-01

    Arsenic contamination of stream waters and groundwater is a real issue in Au-As mine environments. At the Salsigne Au-As mine, southern France, arsenic contamination persists after closure and remediation of the site. In this study, natural and anthropogenic arsenic inputs in surface water and groundwater are identified based on 87Sr/86Sr, and δ18O and δ2H isotopic composition of water. In the wet season, downstream of the remediated zone, the arsenic contents in stream water and alluvial aquifer groundwater are high, with values in the order of 36 μg/L and 40 μg/L respectively, while upstream natural background average concentrations are around 4 μg/L. Locally down-gradient of the reclaimed area, arsenic concentrations in stream water showed 2 peaks, one during an important rainy event (101 mm) in the wet season in May, and a longer one over the dry period, reaching 120 and 110 μg/L respectively. The temporal variations in arsenic content in stream water can be explained i) during the dry season, by release of arsenic stored in the alluvial sediments through increased contribution from base flow and decreased stream flow and ii) during major rainy events, by mobilization of arsenic associated with important surface runoff. The 87Sr/86Sr ratios associated with increasing arsenic content in stream waters downstream of the reclaimed area are significantly lower than that of the natural Sr inherited from Variscan formations. These low 87Sr/86Sr ratios are likely to be associated with the decontaminating water treatment processes, used in the past and still at present, where CaO, produced from marine limestone and therefore showing a low 87Sr/86Sr ratios, is used to precipitate Ca3(AsO4)2. The low Sr isotope signatures will then impact on the Sr isotope ratio of (1) the Ca-arsenate stored in tailing dams, (2) effluent currently produced by water treatment process and (3) groundwater draining from the overall site. Furthermore, Δ2H shows that the low 87Sr/86Sr

  12. Tracking natural and anthropogenic origins of dissolved arsenic during surface and groundwater interaction in a post-closure mining context: Isotopic constraints.

    PubMed

    Khaska, Mahmoud; Le Gal La Salle, Corinne; Verdoux, Patrick; Boutin, René

    2015-01-01

    Arsenic contamination of stream waters and groundwater is a real issue in Au-As mine environments. At the Salsigne Au-As mine, southern France, arsenic contamination persists after closure and remediation of the site. In this study, natural and anthropogenic arsenic inputs in surface water and groundwater are identified based on (87)Sr/(86)Sr, and δ(18)O and δ(2)H isotopic composition of water. In the wet season, downstream of the remediated zone, the arsenic contents in stream water and alluvial aquifer groundwater are high, with values in the order of 36 μg/L and 40 μg/L respectively, while upstream natural background average concentrations are around 4 μg/L. Locally down-gradient of the reclaimed area, arsenic concentrations in stream water showed 2 peaks, one during an important rainy event (101 mm) in the wet season in May, and a longer one over the dry period, reaching 120 and 110 μg/L respectively. The temporal variations in arsenic content in stream water can be explained i) during the dry season, by release of arsenic stored in the alluvial sediments through increased contribution from base flow and decreased stream flow and ii) during major rainy events, by mobilization of arsenic associated with important surface runoff. The (87)Sr/(86)Sr ratios associated with increasing arsenic content in stream waters downstream of the reclaimed area are significantly lower than that of the natural Sr inherited from Variscan formations. These low (87)Sr/(86)Sr ratios are likely to be associated with the decontaminating water treatment processes, used in the past and still at present, where CaO, produced from marine limestone and therefore showing a low (87)Sr/(86)Sr ratios, is used to precipitate Ca3(AsO4)2. The low Sr isotope signatures will then impact on the Sr isotope ratio of (1) the Ca-arsenate stored in tailing dams, (2) effluent currently produced by water treatment process and (3) groundwater draining from the overall site. Furthermore, Δ(2)H shows

  13. Glycol Ethers As Groundwater Contaminants

    NASA Astrophysics Data System (ADS)

    Ross, Benjamin; Johannson, Gunnar; Foster, Gregory D.; Eckel, William P.

    1992-01-01

    Ether derivatives of dihydroxy alcohols, which are formed from ethylene or propylene, comprise an important group of groundwater contaminants known as glycol ethers. Compounds in this group are used as solvents, cleaning agents, and emulsifiers in many chemical products and manufacturing operations. Glycol ethers have been associated with a variety of toxic effects, and some compounds in the group are relatively potent teratogens. The limited information available suggests that glycol ethers are contaminants in groundwater, especially in anaerobic plumes emanating from disposal of mixed industrial and household waste. Most methods used to analyze groundwater samples cannot adequately detect μg/? (ppb) concentrations of glycol ethers, and the existing methods perform worst for the most widely used and toxic species. A new method capable of analyzing μg/? concentrations of glycol ethers was recently developed, and its use is recommended for groundwater samples where glycol ethers are likely to be present.

  14. The Diverse Microbiology of Anaerobic Fe(II) Oxidation

    NASA Astrophysics Data System (ADS)

    Coates, J. D.; Weber, K. A.; Scherer, M.; Achenbach, L. A.

    2007-12-01

    Although anaerobic microbial oxidation of Fe(II) has been know for over a decade there is still a paucity of information available on this important metabolic process or the organisms involved. Recent studies have indicated that the metabolism is ubiquitous and a broad diversity of organisms are capable of oxidizing Fe(II) in the absence of oxygen. Our previous studies demonstrated the existence of geochemical conditions conducive to supporting the activity of nitrate-dependent Fe(II) oxidizing bacteria (NFoB) in sedimentary environments. As part of these studies we isolated and characterized several novel NFoBs. Three of these organisms, Diaphorobacter sp. strain TPSY, Ferrutens nitratireducens strain 2002 and Azospira suillum strain PS are currently undergoing whole genome shotgun sequencing in an effort to gain insight into the biochemistry and molecular biology of this geochemically important metabolism. These organisms represent diverse genera capable of anaerobically oxidizing Fe(II) using nitrate as the electron acceptor. Two of these organisms, strain 2002 and strain TPSY, are also capable of the anaerobic nitrate-dependent oxidation of U(IV) to U(VI). Diaphorobacter sp. strain TPSY was isolated from uranium and nitrate contaminated groundwater and is a member of the Comamonadaceae family in the beta subclass of the Proteobacteria, closely related to Diaphorobacter nitroreducens. It represents the first example of an anaerobic Fe(II)-oxidizer from the Comamonadaceae family and grows mixotrophically requiring an organic carbon source when growing with Fe(II) and nitrate as the electron donor and acceptor respectively. F. nitratireducens strain 2002 was isolated from aquatic sediment and is the type strain of a new genus, Ferrutens, in the beta class of the Proteobacteria. Its closest relative is Chromobacterium violaceum, a common soil bacterium. In contrast to C. violaceum, F. nitratireducens is non-fermentative and does not produce free cyanide (CN-) or

  15. Groundwater in times of droughts

    NASA Astrophysics Data System (ADS)

    Attinger, Sabine; Kumar, Rohini; Musuuza, Jude; Samaniego, Luis

    2014-05-01

    Droughts are characterized as sustained and regionally extensive occurrences of below-average natural water availability. They affect all components of the water cycle: from deficits in soil moisture (agricultural droughts) through reduced groundwater recharge and groundwater levels to low streamflows or dried-up rivers (hydrological droughts). Groundwater discharge is a significant component of streamflow, with groundwater contributing as much as 90 percent of annual streamflow volume in some parts of the U.S., Canada and Europe (Beck et al., 2013). And groundwater systems strongly control the hydrological drought characteristics all over the world (van Lanen et al., 2013). Making use of large scale hydrological models van Lanen demonstrated that groundwater systems substantially affect the duration, particularly of the more extreme drought events. The responsiveness of the groundwater system is as important as climate for hydrological drought development. This urges for an improvement of subsurface modules in conceptual hydrological models to be more useful for water resources assessments. In this talk, we will discuss different subsurface modeling approaches ranging from spatially distributed groundwater models to simpler reservoir-type modeling approaches and the implications the chosen model has on modelled groundwater droughts and base flow characteristics. In particular, we discuss a standardized groundwater drought index (SGI) to characterize the groundwater deficit and the groundwater head anomalies. Based on SGI, we investigate different statistics (severity, area and duration) of individual drought events for the different model approaches. These results will be related to locally measured groundwater data.

  16. Modelling natural attenuation of heavy-metal groundwater contamination in the Selebi-Phikwe mining area, Botswana

    NASA Astrophysics Data System (ADS)

    Schwartz, M. O.; Kgomanyane, J.

    2008-04-01

    Seepage from a tailings dam is the major source of groundwater pollution in the Selebi-Phikwe area, where mining of sulphidic nickel-copper-cobalt ore started in 1973 and will continue until 2014. The seepage water has a pH in the range of 1.7-2.8 and is strongly enriched in SO4 2- (5,680 g/L) and heavy metals (6,230 μg/L Ni, 1,860 μg/L Cu and 410 μg/L Co). The fracture aquifer affected by pollution from the dam exhibits a remarkable capacity of heavy-metal sorption. Most of the Ni, Cu and Co is scavenged at less than 500 m distance downgradient from the polluting source, whereas SO4 2- is not immobilized significantly. The heavy-metal sorption process is assumed to be due to surface complexation, which is supported by a relatively high groundwater pH (in the range of 6.2-7.8 at >200 m distance from the tailings dam). The objective of this study is to demonstrate that the sorption process can be incorporated into a realistic three-dimensional reactive-transport groundwater model that is implicitly charge-balanced. The simulations are performed with the PHAST1.2 program, which is based on the HST3D flow and transport code and the hydrochemical PHREEQC2.12 code.

  17. Combining the soilwater balance and water-level fluctuation methods to estimate natural groundwater recharge: Practical aspects

    USGS Publications Warehouse

    Sophocleous, M.A.

    1991-01-01

    A relatively simple and practical approach for calculating groundwater recharge in semiarid plain environments with a relatively shallow water table, such as the Kansas Prairies, is outlined. Major uncertainties in the Darcian, water balance, and groundwater fluctuation analysis approaches are outlined, and a combination methodology for reducing some of the uncertainties is proposed. By combining a storm-based soilwater balance (lasting several days) with the resulting water table rise, effective storativity values of the region near the water table are obtained. This combination method is termed the 'hybrid water-fluctuation method'. Using a simple average of several such estimates results in a site-calibrated effective storativity value that can be used to translate each major water-table rise tied to a specific storm period into a corresponding amount of groundwater recharge. Examples of soilwater balance and water-level fluctuation analyses based on field-measured data from Kansas show that the proposed methodology gives better and more reliable results than either of the two well-established approaches used singly. ?? 1991.

  18. Arsenic Cycling in Hydrocarbon Plumes: Secondary Effects of Natural Attenuation.

    PubMed

    Cozzarelli, Isabelle M; Schreiber, Madeline E; Erickson, Melinda L; Ziegler, Brady A

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction. PMID:25612004

  19. Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

    USGS Publications Warehouse

    Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

  20. Monitoring Anaerobic TCE Degradation by Evanite Cultre in Column Packed with TCE-Contaminated Soil

    NASA Astrophysics Data System (ADS)

    Ko, J.; Han, K.; Ahn, G.; Park, S.; Kim, N.; Ahn, H.; Kim, Y.

    2011-12-01

    Trichloroethylene (TCE) is a long-term common groundwater pollutant because the compound with high density is slowly released into groundwater. Physical and chemical remediation processes have been used to clean-up the contaminant, but novel remediation technology is required to overcome a low efficiency of the traditional treatment process. Many researchers focused on biological process using an anaerobic TCE degrading culture, dehalococcoides spp., but it still needs to evaluate whether the process can be applied into field scale under aerobic condition. Therefore, in this work we examined two different types (i.e., Natural attenuation and bioaugmentation) of biological remediation process in anaerobic column packed with TCE-contaminated soil. A TCE degradation by indigenous microorganisms was confirmed by monitoring TCE and the metabolites (c-DCE, VC, ETH). However, TCE was transformed and stoichiometry amount of c-DCE was produced, and VC and ETH was not detected. To test bioaugmentation of Evanite culture containing dehalococcoides spp., Evanite culture was injected into the column and TCE degradation to c-DCE, VC, ETH was monitored. We are evaluating the transport of the Evanite culture in the column by measuring TCE and VC reductases. In the result, the TCE was completely degraded to ETH using hydrogen as electron donor generate by hydrogen-production fermentation from formate.

  1. Source and distribution of naturally occurring arsenic in groundwater from Alberta’s Southern Oil Sands Regions

    SciTech Connect

    Moncur, Michael C.; Paktunc, Dogan; Jean Birks, S.; Ptacek, Carol J.; Welsh, Brent; Thibault, Yves

    2015-11-01

    Arsenic (As) concentrations as high as 179 μg/L have been observed in shallow groundwater in the Alberta’s Southern Oil Sand Regions. The geology of this area of Alberta includes a thick cover (up to 200 m) of unconsolidated glacial deposits, with a number of regional interglacial sand and gravel aquifers, underlain by marine shale. Arsenic concentrations observed in 216 unconsolidated sediment samples ranged from 1 and 17 ppm. A survey of over 800 water wells sampled for As in the area found that 50% of the wells contained As concentrations exceeding drinking water guidelines of 10 μg/L. Higher As concentrations in groundwater were associated with reducing conditions. Measurements of As speciation from 175 groundwater samples indicate that As(III) was the dominant species in 74% of the wells. Speciation model calculations showed that the majority of groundwater samples were undersaturated with respect to ferrihydrite, suggesting that reductive dissolution of Fe-oxyhydroxides may be the source of some As in groundwater. Detailed mineralogical characterization of sediment samples collected from two formations revealed the presence of fresh framboidal pyrite in the deeper unoxidized sediments. Electron microprobe analysis employing wavelength dispersive spectrometry indicated that the framboidal pyrite had variable As content with an average As concentration of 530 ppm, reaching up to 1840 ppm. In contrast, the oxidized sediments did not contain framboidal pyrite, but exhibited spheroidal Fe-oxyhydroxide grains with elevated As concentrations. The habit and composition suggest that these Fe-oxyhydroxide grains in the oxidized sediment were an alteration product of former framboidal pyrite grains. X-ray absorption near edge spectroscopy (XANES) indicated that the oxidized sediments are dominated by As(V) species having spectral features similar to those of goethite or ferrihydrite with adsorbed As, suggesting that Fe-oxyhydroxides are the dominant As carriers

  2. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Estimated Mean Annual Natural Groundwater Recharge, 2002

    USGS Publications Warehouse

    Wieczorek, Michael E.; LaMotte, Andrew E.

    2010-01-01

    This tabular data set represents the mean annual natural groundwater recharge, in millimeters, compiled for every MRB_E2RF1catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data set is Estimated Mean Annual Natural Ground-Water Recharge in the Conterminous United States (Wolock, 2003). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

  3. Persistent source influences on the trailing edge of a groundwater plume, and natural attenuation timeframes: the F-Area Savannah River Site.

    PubMed

    Wan, Jiamin; Tokunaga, Tetsu K; Dong, Wenming; Denham, Miles E; Hubbard, Susan S

    2012-04-17

    At the Savannah River Site's F-Area, wastewaters containing radionuclides were disposed into seepage basins for decades. After closure and capping in 1991, the U.S. Department of Energy (DOE) has being monitoring and remediating the groundwater plume. Despite numerous studies of the plume, its persistence for over 20 years has not been well understood. To better understand the plume dynamics, a limited number of deep boreholes were drilled to determine the current plume characteristics. A mixing model was developed to predict plume tritium and nitrate concentrations. We found that the plume trailing edges have emerged for some contaminants, and that contaminant recharge from the basin's vadose zone is still important. The model's estimated time-dependent basin drainage rates combined with dilution from natural recharge successfully predicted plume tritium and nitrate concentrations. This new understanding of source zone influences can help guide science-based remediation, and improve predictions of the natural attenuation timeframes. PMID:22432961

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

    USGS Publications Warehouse

    Olsen, Lisa D.; Tenbus, Frederick J.

    2005-01-01

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

  5. Monitoring in Situ Anaerobic Alkylbenzene Biodegradation Based on Mass Spectrometric Detection of Unique Metabolites or Real-Time PCR Detection of a Catabolic Gene

    NASA Astrophysics Data System (ADS)

    Beller, H. R.; Kane, S. R.

    2002-12-01

    Monitored natural attenuation (MNA) can be a cost-effective and viable approach for remediation of hydrocarbon-contaminated groundwater. However, regulatory acceptance of the approach is often contingent on monitoring that can convincingly demonstrate the role of microbial degradation. Recent advances in anaerobic hydrocarbon biochemistry, analytical chemistry, and molecular biology have fostered the development of powerful new techniques that can be applied to MNA of BTEX (benzene, toluene, ethylbenzene, and xylenes). Here we report two independent methods that have been developed to monitor in situ, anaerobic biodegradation of toluene and xylenes. A method has been developed for rapid, sensitive, and highly selective detection of distinctive indicators of anaerobic alkylbenzene metabolism. The target metabolites, benzylsuccinic acid (BS) and methylbenzylsuccinic acid (MeBS) isomers, have no known sources other than anaerobic toluene or xylene degradation; thus, their mere presence in groundwater provides definitive evidence of in situ metabolism. The method, which involves small sample size (<1 mL) and no extraction/concentration steps, relies on isotope dilution liquid chromatography/tandem mass spectrometry (LC/MS/MS) with selected reaction monitoring. Detection limits for benzylsuccinates were determined to be ca. 0.3 μg/L and accuracy and precision were favorable in a groundwater matrix. The LC/MS/MS method was used to characterize geographic and temporal distributions of benzylsuccinates in an anaerobic, hydrocarbon-contaminated aquifer. BS was never detected and MeBS isomers were detected in the three wells with the highest concentrations of BTEX; MeBS concentrations ranged from <0.3 to 205 μg/L. A strong linear correlation was found between concentrations of total MeBS isomers and their parent compounds, xylenes. A monitoring method based on real-time Polymerase Chain Reaction (PCR) analysis has been developed to specifically quantify populations of

  6. Anaerobic bag culture method.

    PubMed

    Rosenblatt, J E; Stewart, P R

    1975-06-01

    In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. PMID:1100671

  7. Anaerobic bag culture method.

    PubMed Central

    Rosenblatt, J E; Stewart, P R

    1975-01-01

    In a new method of anaerobic culture, a transparent, gas-impermeable bag is used and the anaerobic environment is established with copper sulfate-saturated steel wool. An Alka-Seltzer tablet generates carbon dioxide. The agar plate surface can be inspected through the bag at any time without interrupting the anaerobic atmosphere or disturbing other specimens. Methylene blue indicator strips are completely reduced by 4 h after the bag is set up and have remained reduced for as long as 3 weeks. Growth of 16 different stock culture anaerobes was generally equivalent by the bag and GasPak jar methods. Yield and growth of anaerobic isolates also were equivalent with 7 of 10 clinical specimens; from the other 3 specimens, 13 isolates were recovered, 5 by both the bag and jar methods and the rest by one method or the other. No consistent differences were found between the anaerobic bag and GasPak jar methods in the yield of anaerobes from clinical specimens. Early growth (24 h of incubation) of anaerobes from one specimen was detected with the bag method. Images PMID:1100671

  8. Anaerobic thermophilic culture

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A newly discovered thermophilic anaerobe is described that was isolated in a biologically pure culture and designated Thermoanaerobacter ethanolicus ATCC 3/550. T. Ethanolicus is cultured in aqueous nutrient medium under anaerobic, thermophilic conditions and is used in a novel process for producing ethanol by subjecting carbohydrates, particularly the saccharides, to fermentation action of the new microorganism in a biologically pure culture.

  9. Anaerobic specimen transport device.

    PubMed Central

    Wilkins, T D; Jimenez-Ulate, F

    1975-01-01

    A device is described and evaluated for the anaerobic transport of clinical specimens. The device limits the amount of oxygen entering with the sample to a maximum of 2%, which is rapidly removed by reacting with hydrogen in the presence of a palladium catalyst. The viability on swabs of 12 species of anaerobes, four strains of facultative anaerobes and a strain of Pseudomonas aeruginosa, was maintained during the length of the tests (24 or 48 h). The results demonstrated that this device protected even the more oxygen-sensitive clinical anaerobes from death due to oxygen exposure. This device can be used for swabs as well as for anaerobic collection and liquid and solid specimens. Images PMID:1104656

  10. The effect of salinization and freshening events in coastal aquifers on nutrient characteristics as deduced from column experiments under aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Russak, A.; Sivan, O.; Herut, B.; Lazar, B.; Yechieli, Y.

    2015-10-01

    This study experimentally quantified the effect of seawater intrusion (salinization) and freshening events in coastal aquifers on nutrient (N, P and DSi) dynamics across the fresh-saline groundwater interface. Laboratory column experiments were conducted under aerobic and anaerobic conditions in order to simulate the processes occurring in the fresh-saline interface. They were performed with aquifer sediments, simulating the natural conditions during alterations of natural fresh groundwater to seawater and vice versa. The salinization and freshening experiments showed that NH4+ and PO43- and DSi were affected mainly by ion exchange processes while microbial activity controlled the nitrogen species NO3- and NO2-. Due to the cation exchange, salinization generated enrichment (above the expected conservative behavior) of NH4+, up to 80 μmol L-1 (an order of magnitude higher than in seawater or fresh groundwater). Under anaerobic conditions NO3- was removed by denitrification, as demonstrated by the decrease in NO3- concentrations, the increase in NO2- concentrations, and the increase in δ15N by 15-25‰. Clear evidence was shown for anion exchange of PO43-, which competes with HCO3- and boron on adsorption sites. DSi seems to take part in the exchange process, similar to PO43-.