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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Electrical Resistivity Imaging For Long-Term Autonomous Monitoring Of Hydrocarbon Degradation: Lessons From The Deepwater Horizon Oil Spill, Jeffrey W. Heenan, Lee D. Slater, Dimitrios Ntarlagiannis, Estella A. Atekwana, Babu Z. Fathepure, Sonal Dalvi, Cameron Ross, D. Dale Werkema, Eliot A. Atekwana
Electrical Resistivity Imaging For Long-Term Autonomous Monitoring Of Hydrocarbon Degradation: Lessons From The Deepwater Horizon Oil Spill, Jeffrey W. Heenan, Lee D. Slater, Dimitrios Ntarlagiannis, Estella A. Atekwana, Babu Z. Fathepure, Sonal Dalvi, Cameron Ross, D. Dale Werkema, Eliot A. Atekwana
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Conceptual models for the geophysical responses associated with hydrocarbon degradation suggest that the long-term evolution of an oil plume will result in a more conductive anomaly than the initial contamination. In response to the Deepwater Horizon (DH) oil spill into the Gulf of Mexico in 2010, an autonomous resistivity monitoring system was deployed on Grand Terre, Louisiana, in an attempt to monitor natural degradation processes in hydrocarbon-impacted beach sediments of this island. A 48-electrode surface array with a 0.5-m spacing was installed to obtain twice-daily images of the resistivity structure of the shallow subsurface impacted by oil. Over the course …
Spectral Induced Polarization (Sip) Response Of Biodegraded Oil In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana
Spectral Induced Polarization (Sip) Response Of Biodegraded Oil In Porous Media, Gamal Z. Abdel Aal, Estella A. Atekwana
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Laboratory experiments were conducted to investigate the effect of different oil saturation (0.2- 0.8), wetting conditions (water-wet and oil-wet), and the addition of asphaltene on the spectral induced polarization (SIP) response of biodegraded and fresh crude oil in sand columns. In the water-wet case, no significant differences were observed for both the fresh and biodegraded oil and both displayed an increase in the magnitude of the phase (φ) and decrease in the magnitudes of the real (σ′) and imaginary (σ″) conductivity components with increasing oil saturation. In this instance the SIP response is most likely controlled by the conduction and …
Magnetic Susceptibility As A Proxy For Investigating Microbially Mediated Iron Reduction, Farag M. Mewafy, Estella A. Atekwana, D. Dale Werkema, Lee D. Slater, Dimitrios Ntarlagiannis, Andre Revil, Magnus E. Skold, Geoffrey N. Delin
Magnetic Susceptibility As A Proxy For Investigating Microbially Mediated Iron Reduction, Farag M. Mewafy, Estella A. Atekwana, D. Dale Werkema, Lee D. Slater, Dimitrios Ntarlagiannis, Andre Revil, Magnus E. Skold, Geoffrey N. Delin
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We investigated magnetic susceptibility (MS) variations in hydrocarbon contaminated sediments. Our objective was to determine if MS can be used as an intrinsic bioremediation indicator due to the activity of iron-reducing bacteria. A contaminated and an uncontaminated core were retrieved from a site contaminated with crude oil near Bemidji, Minnesota and subsampled for MS measurements. The contaminated core revealed enriched MS zones within the hydrocarbon smear zone, which is related to iron-reduction coupled to oxidation of hydrocarbon compounds and the vadose zone, which is coincident with a zone of methane depletion suggesting aerobic or anaerobic oxidation of methane is coupled …
Temporal Geophysical Signatures From Contaminant-Mass Remediation, Vukenkeng Che-Alota, Estella A. Atekwana, Eliot A. Atekwana, William August Sauck, D. Dale Werkema
Temporal Geophysical Signatures From Contaminant-Mass Remediation, Vukenkeng Che-Alota, Estella A. Atekwana, Eliot A. Atekwana, William August Sauck, D. Dale Werkema
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We have previously documented changes in bulk electrical conductivity, self-potential (SP), and ground-penetrating-radar (GPR) reflections in a field setting caused by biogeochemical transformations of hydrocarbon-contaminated media. These transformations are associated with hydrocarbon biodegradation. The results of surface geophysical surveys acquired in 1996, 2003, and 2007 document changes in geophysical signatures associated with removing hydrocarbon mass in the contaminated zone. Initial investigations in 1996 showed that relative to background, the contaminated area was characterized by higher bulk electrical conductivity, positive SP anomaly, and attenuated GPR reflections. Repeated surveys in 2003 and 2007 over the contaminated area showed that in 2007, the …
Induced-Polarization Measurements On Unconsolidated Sediments From A Site Of Active Hydrocarbon Biodegradation, Gamal Z. Abdel Aal, Lee D. Slater, Estella A. Atekwana
Induced-Polarization Measurements On Unconsolidated Sediments From A Site Of Active Hydrocarbon Biodegradation, Gamal Z. Abdel Aal, Lee D. Slater, Estella A. Atekwana
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
To investigate the potential role that indigenous microorganisms and microbial processes may play in altering low frequency electrical properties, induced-polarization (IP) measurements in the frequency range of 0.1 to 1000 Hz were acquired from sediment samples retrieved from a site contaminated by hydrocarbon undergoing intrinsic biodegradation. Increased imaginary conductivity and phase were observed for samples from the smear zone (contaminated with residual-phase hydrocarbon), exceeding values obtained for samples contaminated with dissolved-phase hydrocarbons, and in turn, exceeding values obtained for uncontaminated samples. Real conductivity, although generally elevated for samples from the smear zone, did not show a strong correlation with contamination. …
In-Situ Apparent Conductivity Measurements And Microbial Population Distribution At A Hydrocarbon-Contaminated Site, Estella A. Atekwana, D. Dale Werkema, Joseph W. Duris, Silvia Rossbach, Eliot A. Atekwana, William A. Sauck, Daniel P. Cassidy, Jay Means, Franklyn D. Legall
In-Situ Apparent Conductivity Measurements And Microbial Population Distribution At A Hydrocarbon-Contaminated Site, Estella A. Atekwana, D. Dale Werkema, Joseph W. Duris, Silvia Rossbach, Eliot A. Atekwana, William A. Sauck, Daniel P. Cassidy, Jay Means, Franklyn D. Legall
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light nonaqueous-phase liquid (LNAPL). The bulk conductivity was measured using in-situ vertical resistivity probes; the most probable number method was used to characterize the spatial distribution of aerobic heterotrophic and oil-degrading microbial populations. The purpose of this study was to assess if high conductivity observed at aged LNAPL-impacted sites may be related to microbial degradation of LNAPL. The results show higher bulk conductivity coincident with LNAPL-impacted zones, in contrast to geoelectrical models that predict lower conductivity in such zones. The highest bulk conductivity …
Investigating The Geoelectrical Response Of Hydrocarbon Contamination Undergoing Biodegradation, D. Dale Werkema, Estella A. Atekwana, Anthony L. Endres, William August Sauck, Daniel P. Cassidy
Investigating The Geoelectrical Response Of Hydrocarbon Contamination Undergoing Biodegradation, D. Dale Werkema, Estella A. Atekwana, Anthony L. Endres, William August Sauck, Daniel P. Cassidy
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
A newly proposed geoelectrical model for hydrocarbon contaminated sites predicts high conductivities coincident with the contaminated zone as opposed to the traditionally accepted low conductivity. The model attributes the high conductivities to mineral weathering resulting from byproducts of microbial redox processes. To evaluate this conductive model, in situ vertical conductivity measurements were acquired from a light non-aqueous phase liquid (LNAPL) contaminated site. The results showed high conductivities coincident with the zone of contamination and within the smear zone influenced by seasonal water table fluctuations. We infer this zone as an active zone of biodegradation and suggest significant microbial degradation under …