Shallow Aquifer
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. Aerobic biodegradation of vinyl chloride in groundwater samples.
Studies were conducted to examine the biodegradation of 14C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to 14CO2.
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14. Extrapolation of biodegradation results to groundwater aquifers: reductive dehalogenation of aromatic compounds.
The reductive biodegradation of a variety of haloaromatic substrates was monitored in samples from two sites within a shallow anoxic aquifer and was compared with freshwater sediment and sewage sludge. The metabolic capacity existing in methane-producing aquifer material was very similar to that in sediment in that three of four chlorobenzoates, five of seve
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15. Identification and catabolic activity of well-derived gasoline-degrading bacteria from a contaminated aquifer.
Approximately 300 gasoline-degrading bacteria were isolated from well water and core material from a shallow coastal aquifer contaminated with unleaded gasoline. Identification of 244 isolates revealed four genera: Pseudomonas, Alcaligenes, Nocardia, and Micrococcus, with pseudomonads making up 86.9% of bacteria identified. A total of 297 isolates was sorted
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16. Influence of Alternate Electron Acceptors on the Metabolic Fate of Hydroxybenzoate Isomers in Anoxic Aquifer Slurries
The biodegradation of hydroxybenzoate isomers was investigated with samples obtained from two sites within a shallow anoxic aquifer. The metabolic fates of the substrates were compared in denitrifying, sulfate-reducing, and methanogenic incubations. Under the latter two conditions, phenol was detected as a major intermediate of p-hydroxybenzoate, but no meta
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17. In Situ Exposure to Low Herbicide Concentrations Affects Microbial Population Composition and Catabolic Gene Frequency in an Aerobic Shallow Aquifer
The aim of this study was to evaluate how the in situ exposure of a Danish subsurface aquifer to phenoxy acid herbicides at low concentrations (<40 μg l−1) changes the microbial community composition. Sediment and groundwater samples were collected inside and outside the herbicide-exposed area and were analyzed for the presence of general microbial popula
American Society for Microbiology.
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18. Determination of In Situ Bacterial Growth Rates in Aquifers and Aquifer Sediments
Laboratory and field-scale studies with stained cells were performed to monitor cell growth in groundwater systems. During cell division, the fluorescence intensity of the protein stain 5-(and 6-)-carboxyfluorescein diacetate succinimidyl ester (CFDA/SE) for each cell is halved, and the intensity can be tracked with a flow cytometer. Two strains of bacteria,
American Society for Microbiology.
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19. Effect of treated-sewage contamination upon bacterial energy charge, adenine nucleotides, and DNA content in a sandy aquifer on Cape Cod.
Changes in adenylate energy charge (ECA) and in total adenine nucleotides (A(T) and DNA content (both normalized to the abundance of free-living, groundwater bacteria) in response to carbon loading were determined for a laboratory-grown culture and for a contaminated aquifer. The latter study involved a 3-km-long transect through a contaminant plume resultin
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20. Molecular Analysis of Microbial Community Structures in Pristine and Contaminated Aquifers: Field and Laboratory Microcosm Experiments
This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron ac
American Society for Microbiology.
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21. Application of a Vital Fluorescent Staining Method for Simultaneous, Near-Real-Time Concentration Monitoring of Two Bacterial Strains in an Atlantic Coastal Plain Aquifer in Oyster, Virginia
Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp. strain OY-107 were grown and labeled with the vital fluorescent stain TAMRA/SE (5 [and -6]-carboxytetramethylrhodamine, succinimidyl
American Society for Microbiology.
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22. Isolation of Geobacter species from diverse sedimentary environments.
In an attempt to better understand the microorganisms responsible for Fe(III) reduction in sedimentary environments, Fe(III)-reducing microorganisms were enriched for and isolated from freshwater aquatic sediments, a pristine deep aquifer, and a petroleum-contaminated shallow aquifer. Enrichments were initiated with acetate or toluene as the electron donor a
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23. The influence of sulfur and iron on dissolved arsenic concentrations in the shallow subsurface under changing redox conditions
The chemical speciation of arsenic in sediments and porewaters of aquifers is the critical factor that determines whether dissolved arsenic accumulates to potentially toxic levels. Sequestration of arsenic in solid phases, which may occur by adsorption or precipitation processes, controls dissolved concentrations. We present synchrotron x-ray absorption spec
National Academy of Sciences.
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24. Aerobic biodegradation potential of subsurface microorganisms from a jet fuel-contaminated aquifer.
In 1975, a leak of 83,000 gallons (314,189 liters) of jet fuel (JP-4) contaminated a shallow water-table aquifer near North Charleston, S.C. Laboratory experiments were conducted with contaminated sediments to assess the aerobic biodegradation potential of the in situ microbial community. Sediments were incubated with 14C-labeled organic compounds, and the e