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Sample records for contaminant plume delineation

  1. Methane oxidation in a crude oil contaminated aquifer: Delineation of aerobic reactions at the plume fringes

    USGS Publications Warehouse

    Amos, R.T.; Bekins, B.A.; Delin, G.N.; Cozzarelli, I.M.; Blowes, D.W.; Kirshtein, J.D.

    2011-01-01

    High resolution direct-push profiling over short vertical distances was used to investigate CH4 attenuation in a petroleum contaminated aquifer near Bemidji, Minnesota. The contaminant plume was delineated using dissolved gases, redox sensitive components, major ions, carbon isotope ratios in CH4 and CO2, and the presence of methanotrophic bacteria. Sharp redox gradients were observed near the water table. Shifts in ??13CCH4 from an average of - 57.6??? (?? 1.7???) in the methanogenic zone to - 39.6??? (?? 8.7???) at 105 m downgradient, strongly suggest CH4 attenuation through microbially mediated degradation. In the downgradient zone the aerobic/anaerobic transition is up to 0.5 m below the water table suggesting that transport of O2 across the water table is leading to aerobic degradation of CH4 at this interface. Dissolved N2 concentrations that exceeded those expected for water in equilibrium with the atmosphere indicated bubble entrapment followed by preferential stripping of O2 through aerobic degradation of CH4 or other hydrocarbons. Multivariate and cluster analysis were used to distinguish between areas of significant bubble entrapment and areas where other processes such as the infiltration of O 2 rich recharge water were important O2 transport mechanisms. ?? 2011 Elsevier B.V. All rights reserved.

  2. Detailed Vertical and Lateral Delineation of Redox Zones in Contaminant Plumes Using Redox-Sensitive Tapes (RST)

    NASA Astrophysics Data System (ADS)

    Blum, P.; Oeste, F. D.; Melzer, R.; Martus, P.

    2006-12-01

    Innovative redox-sensitive tapes (RST) have been developed for a detailed vertical and lateral delineation of redox zones in contaminated aquifers. The RST have the potential to become an integral part of a data acquisition strategy for monitored natural attenuation (MNA). The tape material, consists of a 2 cm wide synthetic textile coated with reactive manganese dioxide minerals. The RST are submerged into existing monitoring wells for approximately one month. This time period is sufficient to allow for a reaction of the mineral coating with groundwater. The RST are aimed at investigating four different redox-zones in contaminated aquifers: Mn(II)-oxidizing, Mn(IV)-reducing, Fe(III)-reducing and sulfate-reducing. Two RST case studies are presented. The RST investigations on a coal tar contaminated site allowed for a precise lateral and vertical delineation of the contaminant plume using the existing monitoring well network. The RST investigations on a BTEX contaminated site yielded a good correlation of RST data with hydrochemical data at the wells sampled. In the majority of plume wells located 50 m downstream of the source area and beyond, Mn(IV)-reducing environment appeared to be prevailing. Comparing the RST data with hydrochemical data indicated evidence for the transport of transformation products with groundwater flow. The repeated application of the RST facilitated an assessment of the plume dynamics. No significant seasonal variation with respect to the redox zone distribution was observed within the contaminant plume. However, the assessment of the changes in redox conditions over a time period of 2.5 years showed that the iron-reducing zone is shrinking and the sulfate-reducing zone disappeared completely indicating that the contaminant plume might decrease in the near future. Thus, the application of the RST facilitated an assessment of the plume dynamics on a centimeter-scale without the necessity of pumping and treating contaminated groundwater.

  3. Waste and cost reduction using dual wall reverse circulation drilling with multi-level groundwater sampling for contaminant plume delineation

    SciTech Connect

    Smuin, D.R.

    1995-12-01

    This paper describes the drilling and sampling methods used to delineate a groundwater contaminant plume at the Paducah Gaseous Diffusion Plant (PGDP) during the Groundwater Monitoring IV characterization. The project was unique in that it relied upon dual wall reverse circulation drilling instead of the traditional hollow stem auger method. The Groundwater Monitoring program sought to characterize the boundaries, both vertically and horizontally, of the northeast plume which contains both {sup 99}Tc and trichloroethene. This paper discusses the strengths and weaknesses of the drilling method used by investigators.

  4. Migration of contaminants in groundwater at a landfill: A case study. 1. Groundwater flow and plume delineation

    NASA Astrophysics Data System (ADS)

    MacFarlane, D. S.; Cherry, J. A.; Gillham, R. W.; Sudicky, E. A.

    1983-05-01

    A landfill-derived contaminant plume with a maximum width of ˜600 m, a length of ˜700 m and a maximum depth of 20 m in an unconfined sand aquifer was delineated by means of a monitoring network that includes standpipe piezometers, multilevel point-samplers and bundle-piezometers. The extent of detectable contamination caused by the landfill, which began operation in 1940 and which became inactive in 1976, was determined from the distributions of chloride, sulfate and electrical conductance in the sand aquifer, all of which have levels in the leachate that are greatly above those in uncontaminated groundwater. The maximum temperature of groundwater in the zone of contamination beneath the landfill is 12°C, which is 4-5°C above background. The thermal plume in the aquifer extends ˜150 m downgradient from the centre of the landfill. A slight transient water-table mound exists beneath the landfill in the late spring and summer in response to snowmelt and heavy rainfall. Beneath the landfill, the zone of leachate contamination extends to the bottom of the aquifer, apparently because of transient downward components of hydraulic gradient caused by the water-table mound and possibly because of the higher density and lower viscosity of the contaminated water. Values of hydraulic conductivity, which show variations due to local heterogeneity, were obtained from slug tests of piezometers, from pumping tests and from laboratory tests. Because of the inherent uncertainty in the aquifer parameter values, the 38-yr. frontal position of the plume calculated using the Darcy equation with the assumption of plug flow can differ from the observed frontal position by many hundreds of metres, although the use of mean parameter values produces a close agreement. The width of the plume is large relative to the width of the landfill and can be accounted for primarily by variable periods of lateral east- and westward flow caused by changes in water-table configuration due to the

  5. Delineation of discharge areas of two contaminant plumes by use of diffusion samplers, Johns Pond, Cape Cod, Massachusetts, 1998

    USGS Publications Warehouse

    Savoie, Jennifer G.; LeBlanc, D.R.; Blackwood, D.S.; McCobb, T.D.; Rendigs, R. R.; Clifford, Scott

    2000-01-01

    Diffusion samplers were installed in the bottom of Johns Pond, Cape Cod, Massachusetts, to confirm that volatile organic compounds from the Storm Drain-5 (SD-5) plume emanating from the Massachusetts Military Reservation (MMR) were discharging into the pond. An array of 134 vapor-diffusion samplers was buried by divers about 0.5 feet below the pond bottom in the presumed discharge area of the SD-5 plume and left in place for about 2 weeks to equilibrate. Two areas of high concentrations of volatile organic compounds (VOCs) were identified. Samples from the first area contained trichloroethene (TCE) and tetrachloroethene with concentrations in vapor as high as 890 and 667 parts per billion by volume, respectively. This discharge area is about 1,000 feet wide, extends from 100 to 350 feet offshore, and is interpreted to be the discharge area of the SD-5 plume. Samples from the second area were located closer to shore than the discharge area of the SD-5 plume and contained unexpectedly high vapor concentrations of TCE (more than 40,000 parts per billion by volume). Ground-water samples collected with a drive-point sampler near the second area had aqueous TCE concentrations as high as 1,100 micrograms per liter. Subsequently, a more closely spaced array of 110 vapor-diffusion samplers was installed to map the area of elevated TCE concentrations . The discharge area detected with the samplers is about 75 feet wide and extends from about 25 to 200 feet offshore . TCE vapor concentrations in this area were as high as 42,800 parts per billion by volume. TCE concentrations in micrograms per liter in water-diffusion samples from 15 selected sites in the two discharge areas were about 35 times lower than the TCE concentrations in parts per billion by volume in corresponding vapor-diffusion samples. The difference in values is due to the volatile nature of TCE and the different units of measure. TCE was detected in diffusion samplers set in the pond water column above the

  6. Dual wall reverse circulation drilling with multi-level groundwater sampling for groundwater contaminant plume delineation at Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    SciTech Connect

    Smuin, D.R.; Morti, E.E.; Zutman, J.L.; Pickering, D.A.

    1995-08-01

    Dual wall reverse circulation (DWRC) drilling was used to drill 48 borings during a groundwater contaminant investigation at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky. This method was selected as an alternative to conventional hollow stem auger drilling for a number of reasons, including the expectation of minimizing waste, increasing the drilling rate, and reducing the potential for cross contamination of aquifers. Groundwater samples were collected from several water-bearing zones during drilling of each borehole. The samples were analyzed for volatile organic compounds using a field gas chromatograph. This approach allowed the investigation to be directed using near-real-time data. Use of downhole geophysical logging, in conjunction with lithologic descriptions of borehole cuttings, resulted in excellent correlation of the geology in the vicinity of the contaminant plume. The total volume of cuttings generated using the DWRC drilling method was less than half of what would have been produced by hollow stem augering; however, the cuttings were recovered in slurry form and had to be dewatered prior to disposal. The drilling rate was very rapid, often approaching 10 ft/min; however, frequent breaks to perform groundwater sampling resulted in an average drilling rate of < 1 ft/min. The time required for groundwater sampling could be shortened by changing the sampling methodology. Analytical results indicated that the drilling method successfully isolated the various water bearing zones and no cross contamination resulted from the investigation.

  7. Plume Delineation in the BC Cribs and Trenches Area

    SciTech Connect

    Rucker, Dale F.; Sweeney, Mark D.

    2004-11-30

    HydroGEOPHYSICS, Inc. and Pacific Northwest National Laboratory (PNNL) were contracted by Fluor Hanford Group, Inc. to conduct a geophysical investigation in the area of the BC Cribs and Trenches (subject site) at the Hanford Site in Richland, Washington. The BC Cribs and Trenches are located south of the 200 East Area. This document provides the details of the investigation to identify existing infrastructure from legacy disposal activities and to delineate the edges of a groundwater plume that contains radiological and heavy metal constituents beneath the 216-B-26 and 216-B-52 Trenches, and the 216-B-14 through 216-B-19 Cribs.

  8. ModBack - simplified contaminant source zone delineation using backtracking

    NASA Astrophysics Data System (ADS)

    Thielsch, K.; Herold, M.; Ptak, T.

    2012-12-01

    al. (2005). The contaminant plume length can be estimated using plume length statistics, first order rate degradation equations or calculations based on site specific hydraulic and chemical parameters. Furthermore, an analytical tool is included to identify the distribution of contaminants across a control plane. All relevant output can be graphically displayed and saved as vector data to be later used in GIS software. ModBack has been already used to delimit the zones of source presence or absence at several test sites. With ModBack, a tool is now available which enables environmental consultants, engineers and environmental agencies to delineate possible sources of contamination already at the planning stage of site investigation and remediation measures, helping to significantly reduce costs of contaminated site management. Bayer-Raich, M., Jarsjö, J., Holder, T. and Ptak, T. (2003): "Numerical estimations of contaminant mass flow rate based on concentration measurements in pumping wells", ModelCare 2002: A Few Steps Closer to Reality, IAHS Publication No. 277, 10-16. Jarsjö, J., Bayer-Raich, M., Ptak, T. (2005): "Monitoring groundwater contamination and delineating source zones at industrial sites: Uncertainty analyses using integral pumping tests", Journal of Contaminant Hydrology, 79, 107-134

  9. Microbial populations in contaminant plumes

    NASA Astrophysics Data System (ADS)

    Haack, Sheridan K.; Bekins, Barbara A.

    Efficient biodegradation of subsurface contaminants requires two elements: (1) microbial populations with the necessary degradative capabilities, and (2) favorable subsurface geochemical and hydrological conditions. Practical constraints on experimental design and interpretation in both the hydrogeological and microbiological sciences have resulted in limited knowledge of the interaction between hydrogeological and microbiological features of subsurface environments. These practical constraints include: (1) inconsistencies between the scales of investigation in the hydrogeological and microbiological sciences, and (2) practical limitations on the ability to accurately define microbial populations in environmental samples. However, advances in application of small-scale sampling methods and interdisciplinary approaches to site investigations are beginning to significantly improve understanding of hydrogeological and microbiological interactions. Likewise, culture-based and molecular analyses of microbial populations in subsurface contaminant plumes have revealed significant adaptation of microbial populations to plume environmental conditions. Results of recent studies suggest that variability in subsurface geochemical and hydrological conditions significantly influences subsurface microbial-community structure. Combined investigations of site conditions and microbial-community structure provide the knowledge needed to understand interactions between subsurface microbial populations, plume geochemistry, and contaminant biodegradation. La biodégradation efficace des polluants souterrains requiert deux éléments: des populations microbiennes possédant les aptitudes nécessaires à la dégradation, et des conditions géochimiques et hydrologiques souterraines favorables. Des contraintes pratiques sur la conception et l'interprétation des expériences à la fois en microbiologie et en hydrogéologie ont conduit à une connaissance limitée des interactions entre les

  10. RAPID REMOVAL OF A GROUNDWATER CONTAMINANT PLUME.

    USGS Publications Warehouse

    Lefkoff, L. Jeff; Gorelick, Steven M.

    1985-01-01

    A groundwater management model is used to design an aquifer restoration system that removes a contaminant plume from a hypothetical aquifer in four years. The design model utilizes groundwater flow simulation and mathematical optimization. Optimal pumping and injection strategies achieve rapid restoration for a minimum total pumping cost. Rapid restoration is accomplished by maintaining specified groundwater velocities around the plume perimeter towards a group of pumping wells located near the plume center. The model does not account for hydrodynamic dispersion. Results show that pumping costs are particularly sensitive to injection capacity. An 8 percent decrease in the maximum allowable injection rate may lead to a 29 percent increase in total pumping costs.

  11. Hydrocone groundwater study delineates petroleum contamination

    SciTech Connect

    Prochaska, K.; Hartness, J.; Christenson, K.

    1994-12-31

    Law Environmental, Inc., (LAW), conducted a groundwater survey at Myrtle Beach Air Force Base, South Carolina, to delineate the horizontal and vertical extent of petroleum contamination at the BX Service station. The survey was performed using the In-Situ Technology Hydrocone in conjunction with a field gas chromatograph. The Hydrocone proved to be a reliable, cost-effective method of extracting multi-depth groundwater samples without incurring the expenses associated with the installation and maintenance of monitoring wells. The process generates virtually no investigation-derived waste. The Hydrocone system consists of an elongated cylindrical steel sampler attached to drill rods on a direct push trailer mounted rig. A gas/electronic cable connects to the sampler, and a computer installed on the rig displays pressure on the tool, sampling time, and groundwater volume collected. A total of 18 groundwater samples were collected from 12 locations around the site at sampling depths of approximately 10, 20, and 30 feet below the ground surface. The Hydrocone/gas chromatograph method produced a large volume of groundwater quality data within a relatively short time interval.

  12. Monitoring Groundwater Contaminant Plumes Using Airborne Geophysical Data

    NASA Astrophysics Data System (ADS)

    Robinson, Martin; Oftendinger, Ulrich; Ruffell, Alastair; Cowan, Marie; Cassidy, Rachel; Comte, Jean-Christophe; Wilson, Christopher; Desissa, Mohammednur

    2013-04-01

    Under the European Union Water Framework Directive, Member States are required to assess water quality across both surface water and groundwater bodies. Subsurface pollution plumes, originating from a variety of sources, pose a significant direct risk to water quality. The monitoring and characterisation of groundwater contaminant plumes is generally invasive, time consuming and expensive. In particular, adequately capturing the contaminant plume with monitoring installations, when the extent of the feature is unknown and the presence of contamination is only evident from indirect observations, can be prohibitively expensive. This research aims to identify the extent and nature of subsurface contaminant plumes using airborne geophysical survey data. This data was collected across parts of the island of Ireland within the scope of the original Tellus and subsequent Tellus Border projects. The rapid assessment of the airborne electro-magnetic (AEM) data allowed the identification of several sites containing possible contaminant plumes. These AEM anomalies were assessed through the analysis of existing site data and field site inspections, with areas of interest being examined for metallic structures that could affect the AEM data. Electrical resistivity tomography (ERT), ground penetrating radar (GPR) and ground-based electro-magnetic (EM) surveys were performed to ground-truth existing airborne data and to confirm the extent and nature of the affected area identified using the airborne data. Groundwater and surface water quality were assessed using existing field site information. Initial results collected from a landfill site underlain by basalt have indicated that the AEM data, coupled with ERT and GPR, can successfully be used to locate possible plumes and help delineate their extent. The analysis of a range of case study sites exhibiting different geological and environmental settings will allow for the development of a consistent methodology for examining the

  13. Delineating Reactive Natural Attenuation Zones: Multi-level Sampling in an Ammonium Plume

    NASA Astrophysics Data System (ADS)

    Hüttmann, A.; Wilson, R. D.; Thornton, S. F.; Lerner, D. N.

    2003-12-01

    Current natural attenuation monitoring involves observing concentrations along some transect parallel to flow, often in long--screened observation wells. Vertically integrated geochemical signals essentially compresses 3D-problems into 2D ones and the loss of process resolution does not allow for robust plume transport prediction. On the other hand, a monitoring approach that is based on process quantification will yield field data necessary for current natural attenuation assessment and allow more accurate prediction to plume behaviour. To quantify these spatially discrete processes, the resolution of sampling points must be higher to delineate reactive zones, that account for the bulk of natural attenuation. These reactive zones are dependent on aquifer properties, contaminant type, redox zonation and other factors. In many cases, the plume fringe will be the most active zone, because influx of certain nutrients necessary to support bacteria will be greatest in these zones. Most importantly, consortia of degrading bacteria are dependent on supply of electron--acceptors such as dissolved {O2} and nitrate from background ground water and recharge; electron--acceptors are rapidly consumed at the fringes and concentrations decrease significantly towards the centre of the plume. Thus, if a process--based approach is to be achieved, one has to focus not only on the overall extent and mass of a contaminant plume, but, more importantly, on a sound analysis of the most reactive zones. The site of a former coal processing plant in the UK was chosen as a field site where the afore--mentioned hypothesis is currently being investigated by means of two recently installed multi--level samplers. Previous investigations have located an ammonium plume at the site with outwash from the thick unsaturated zone as ongoing source since the demolition of the actual plant in 1970. The conceptual model drawn from the analysis of these data shows that certain zones exhibit higher rates of

  14. Mapping organic contaminant plumes in groundwater using spontaneous potentials

    NASA Astrophysics Data System (ADS)

    Forte, Sarah

    Increased water demands have raised awareness of its importance. One of the challenges facing water resource management is dealing with contaminated groundwater; delineating, characterizing and remediating it. In the last decade, spontaneous potentials have been proposed as a method for delineating degrading organic contaminant plumes in groundwater. A hypothesis proposed that the redox potential gradient due to degradation of contaminants generated an electrical potential gradient that could be measured at the ground surface. This research was undertaken to better understand this phenomenon and find under what conditions it occurs. Spontaneous potentials are electrical potentials generated by three sources that act simultaneously: electrokinetic, thermoelectric and electrochemical sources. Over contaminant plumes electrochemical sources are those of interest. Thermoelectric sources are negligible unless in geothermal areas, but we hypothesized that electrokinetic potentials could be impacted by contaminants altering sediment surface properties. We built and calibrated a laboratory apparatus to make measurements that allowed us to calculate streaming current coupling coefficients. We tested sediment from hydrocarbon impacted sites with clean and hydrocarbon polluted groundwater and found a measurable though inconsistent effect. Moreover, numerical modelling was used to demonstrate that the impact of these changes on field measurements was negligible. Spontaneous potential surveys were conducted on two field sites with well characterized degrading hydrocarbon plumes in groundwater. We did not find a correlation between redox conditions and spontaneous potential, even after the electrical measurements were corrected for anthropogenic noise. In order to determine why the expected signal was not seen, we undertook numerical modelling based on coupled fluxes using two hypothesized types of current: redox and diffusion currents. The only scenarios that produced

  15. Monopropellant thruster exhaust plume contamination measurements

    NASA Technical Reports Server (NTRS)

    Baerwald, R. K.; Passamaneck, R. S.

    1977-01-01

    The potential spacecraft contaminants in the exhaust plume of a 0.89N monopropellant hydrazine thruster were measured in an ultrahigh quartz crystal microbalances located at angles of approximately 0 deg, + 15 deg and + or - 30 deg with respect to the nozzle centerline. The crystal temperatures were controlled such that the mass adhering to the crystal surface at temperatures of from 106 K to 256 K could be measured. Thruster duty cycles of 25 ms on/5 seconds off, 100 ms on/10 seconds off, and 200 ms on/20 seconds off were investigated. The change in contaminant production with thruster life was assessed by subjecting the thruster to a 100,000 pulse aging sequence and comparing the before and after contaminant deposition rates. The results of these tests are summarized, conclusions drawn, and recommendations given.

  16. Reaction front formation in contaminant plumes

    NASA Astrophysics Data System (ADS)

    Cribbin, Laura B.; Winstanley, Henry F.; Mitchell, Sarah L.; Fowler, Andrew C.; Sander, Graham C.

    2014-12-01

    The formation of successive fronts in contaminated groundwater plumes by subsoil bacterial action is a commonly accepted feature of their propagation, but it is not obviously clear from a mathematical standpoint quite how such fronts are formed or propagate. In this paper we show that these can be explained by combining classical reaction-diffusion theory involving just two reactants (oxidant and reductant), and a secondary reaction in which a reactant on one side of such a front is (re-)formed on the other side of the front via diffusion of its product across the front. We give approximate asymptotic solutions for the reactant profiles, and the propagation rate of the front.

  17. Groundwater contaminant plume ranking. [UMTRA Project

    SciTech Connect

    Not Available

    1988-08-01

    Containment plumes at Uranium Mill Tailings Remedial Action (UMTRA) Project sites were ranked to assist in Subpart B (i.e., restoration requirements of 40 CFR Part 192) compliance strategies for each site, to prioritize aquifer restoration, and to budget future requests and allocations. The rankings roughly estimate hazards to the environment and human health, and thus assist in determining for which sites cleanup, if appropriate, will provide the greatest benefits for funds available. The rankings are based on the scores that were obtained using the US Department of Energy's (DOE) Modified Hazard Ranking System (MHRS). The MHRS and HRS consider and score three hazard modes for a site: migration, fire and explosion, and direct contact. The migration hazard mode score reflects the potential for harm to humans or the environment from migration of a hazardous substance off a site by groundwater, surface water, and air; it is a composite of separate scores for each of these routes. For ranking the containment plumes at UMTRA Project sites, it was assumed that each site had been remediated in compliance with the EPA standards and that relict contaminant plumes were present. Therefore, only the groundwater route was scored, and the surface water and air routes were not considered. Section 2.0 of this document describes the assumptions and procedures used to score the groundwater route, and Section 3.0 provides the resulting scores for each site. 40 tabs.

  18. A microbial fuel cell in contaminated ground delineated by electrical self-potential and normalized induced polarization data

    NASA Astrophysics Data System (ADS)

    Doherty, R.; Kulessa, B.; Ferguson, A. S.; Larkin, M. J.; Kulakov, L. A.; Kalin, R. M.

    2010-09-01

    There is a growing interest in the use of geophysical methods to aid investigation and monitoring of complex biogeochemical environments, for example delineation of contaminants and microbial activity related to land contamination. We combined geophysical monitoring with chemical and microbiological analysis to create a conceptual biogeochemical model of processes around a contaminant plume within a manufactured gas plant site. Self-potential, induced polarization and electrical resistivity techniques were used to monitor the plume. We propose that an exceptionally strong (>800 mV peak to peak) dipolar SP anomaly represents a microbial fuel cell operating in the subsurface. The electromagnetic and electrical geophysical data delineated a shallow aerobic perched water body containing conductive gasworks waste which acts as the abiotic cathode of microbial fuel cell. This is separated from the plume below by a thin clay layer across the site. Microbiological evidence suggests that degradation of organic contaminants in the plume is dominated by the presence of ammonium and its subsequent degradation. We propose that the degradation of contaminants by microbial communities at the edge of the plume provides a source of electrons and acts as the anode of the fuel cell. We hypothesize that ions and electrons are transferred through the clay layer that was punctured during the trial pitting phase of the investigation. This is inferred to act as an electronic conductor connecting the biologically mediated anode to the abiotic cathode. Integrated electrical geophysical techniques appear well suited to act as rapid, low cost sustainable tools to monitor biodegradation.

  19. Associations of free-living bacteria and dissolved organic compounds in a plume of contaminated groundwater

    USGS Publications Warehouse

    Harvey, R.W.; Barber, L.B., II

    1992-01-01

    Associations of free-living bacteria (FLB) and dissolved organic contaminants in a 4-km-long plume of sewage-contaminated groundwater were investigated. Abundance of FLB in the core of the plume (as delineated by maximum specific conductance) steadily decreased in the direction of flow from a point 0.25 km downgradient from the source to the toe of the plume. At 0.25 km downgradient, FLB comprised up to 31% of the total bacterial population, but constituted < 7% of the population at 2 km downgradient. Abundance of FLB correlated strongly (r = 0.80 n = 23) with total dissolved organic carbon (DOC) in contaminated groundwater between 0.64 and 2.1 km downgradient, although distributions of individual contaminants such as di-, tri- and tetrachloroethene were highly variable, and their association with FLB less clear. Numbers of FLB in the downgradient portion of the plume which is contaminated with branched-chain alkylbenzenesulfonate (ABS) surfactants were low (< 5??108/L) in spite of relatively high levels of DOC (up to 4 mg/L). However, abundance of FLB correlated strongly with non-surfactant DOC along vertical transects through the plume. The ratio of FLB to DOC and the ratio of FLB to attached bacteria generally decreased in the direction of flow and, consequently, with the age of the organic contaminants.

  20. Reaction front formation in contaminant plumes.

    PubMed

    Cribbin, Laura B; Winstanley, Henry F; Mitchell, Sarah L; Fowler, Andrew C; Sander, Graham C

    2014-12-15

    The formation of successive fronts in contaminated groundwater plumes by subsoil bacterial action is a commonly accepted feature of their propagation, but it is not obviously clear from a mathematical standpoint quite how such fronts are formed or propagate. In this paper we show that these can be explained by combining classical reaction-diffusion theory involving just two reactants (oxidant and reductant), and a secondary reaction in which a reactant on one side of such a front is (re-)formed on the other side of the front via diffusion of its product across the front. We give approximate asymptotic solutions for the reactant profiles, and the propagation rate of the front. PMID:25461883

  1. Groundwater contamination downstream of a contaminant penetration site. I. Extension-expansion of the contaminant plume

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2002-01-01

    This study concerns the possible use of boundary layer (BL) approach for the analysis and evaluation of contaminant transport in groundwater due to contaminant penetration into the groundwater aquifer through a site of limited size. The contaminant penetration may occur through either the upper (surface) or lower (bedrock) boundary of the aquifer. Two general cases of contaminant penetration mechanisms are considered: (1) the contaminant is transferred through an interface between a contaminating and freshwater fluid phases, and (2) the contaminant arrives at groundwater by leakage and percolation. For the purpose of BL evaluation the contaminant plume is divided into three different sections: (1) the penetration section, (2) the extension-expansion section, and (3) the spearhead section. In each section a different BL method approach yields simple analytical expressions for the description of the contaminant plume migration and contaminant transport. Previous studies of the BL method can be directly applied to the evaluation of contaminant transport at the contaminant penetration section. The present study extends those studies and concerns the contaminant transport in the two other sections, which are located downstream of the penetration section. This study shows that the contaminant concentration profiles in sections 2 and 3 incorporate two BLs: (1) an inner BL adjacent to the aquifer bottom or surface boundary, and (2) an outer BL, which develops above or below the inner one. The method developed in the present study has been applied to practical issues concerning salinity penetration into groundwater in south central Kansas.

  2. Comparison of Eh and H2 measurements for delineating redox processes in a contaminated aquifer

    USGS Publications Warehouse

    Chapelle, Francis H.; Haack, Sheridan K.; Adriaens, Peter; Henry, Mark A.; Bradley, Paul M.

    1996-01-01

    Measurements of oxidation−reduction potential (Eh) and concentrations of dissolved hydrogen (H2) were made in a shallow groundwater system contaminated with solvents and jet fuel to delineate the zonation of redox processes. Eh measurements ranged from +69 to −158 mV in a cross section of the contaminated plume and accurately delineated oxic from anoxic groundwater. Plotting measured Eh and pH values on an equilibrium stability diagram indicated that Fe(III) reduction was the predominant redox process in the anoxic zone and did not indicate the presence of methanogenesis and sulfate reduction. In contrast, measurements of H2concentrations indicated that methanogenesis predominated in heavily contaminated sediments near the water table surface (H2 ∼ 7.0 nM) and that the methanogenic zone was surrounded by distinct sulfate-reducing (H2 ∼ 1−4 nM) and Fe(III)-reducing (H2 ∼ 0.1−0.8 nM) zones. The presence of methanogenesis, sulfate reduction, and Fe(III) reduction was confirmed by the distribution of dissolved oxygen, sulfate, Fe(II), and methane in groundwater. These results show that H2 concentrations were more useful for identifying anoxic redox processes than Ehmeasurements in this groundwater system. However, H2-based redox zone delineations are more reliable when H2 concentrations are interpreted in the context of electron-acceptor (oxygen, nitrate, sulfate) availability and the presence of final products [Fe(II), sulfide, methane] of microbial metabolism.

  3. Comparison of three field screening techniques for delineating petroleum hydrocarbon plumes in groundwater at a site in the southern Carson Desert, Nevada

    SciTech Connect

    Smuin, D.R.

    1993-01-01

    Three types of field screening techniques used in the characterization of potentially contaminated sites at Naval Air Station Fallon, Nevada, are compared. The methods and results for each technique are presented. The three techniques include soil-gas surveys, electromagnetic geophysical surveys, and groundwater test hole screening. Initial screening at the first study site included two soil-gas surveys and electromagnetic geophysical studies. These screening methods identified I areas of contamination; however, results were inconclusive. Therefore groundwater test hole screening was performed. Groundwater screening consisted of auger drilling down to the shallow alluvial aquifer. Groundwater samples were collected from the open drill hole with a bailer. On-site head-space analyses for volatile organic compounds (VOCS) were performed using a portable gas chromatograph (GC). Five areas of floating petroleum hydrocarbon product were identified along with the overall dissolved contaminant plume boundaries. Well placement was re-evaluated, and well sites were relocated based on the screening information. The most effective technique for identification of petroleum hydrocarbon-contaminant plumes was groundwater test hole screening. Groundwater screening was subsequently performed at 19 other sites. A total of 450 test holes were analyzed resulting in the delineation of six plumes.

  4. Hydrogeophysical investigations of the former S-3 ponds contaminant plumes

    SciTech Connect

    Revil, Andre; Skold, Magnus E; Karaoulis, Marios; Schmutz, Myriam; Hubbard, Susan S; Mehlhorn, Tonia L; Watson, David B

    2013-01-01

    At the Oak Ridge Integrated Field Research Challenge site, near Oak Ridge, Tennessee, contaminants from the former S-3 ponds have infiltrated the shallow saprolite for over 60 years. Two- and three-dimensional DC-resistivity tomography is used to characterize the number and location of the main contaminant plumes, which include high concentration of nitrate. These contaminant plumes have typically an electrical resistivity in the range 2 20 ohm-m while the background saprolite resistivity is in the range 60 120 ohm-m, so the difference of resistivity can be easily mapped using DC-resistivity tomography to locate the contaminant pathways. We develop a relationship to derive the in situ nitrate concentrations from the 3D resistivity tomograms accounting for the effect of surface conductivity. The footprint of the contamination upon the resistivity is found to be much stronger than the local variations associated with changes in the porosity and the clay content. With this method, we identified a total of five main plumes (termed CP1 to CP5). Plume CP2 corresponds to the main plume in terms of nitrate concentration ( 50,000 ). We also used an active time constrained approach to perform time-lapse resistivity tomography over a section crossing the plumes CP1 and CP2. The sequence of tomograms is used to determine the changes in the nitrate concentrations associated with infiltration of fresh (meteoritic) water from a perched aquifer. This study highlights the importance of accounting for surface conductivity when characterizing plume distributions in clay-rich subsurface systems.

  5. Hydrogeology and leachate plume delineation at a closed municipal landfill, Norman, Oklahoma

    USGS Publications Warehouse

    Becker, Carol J.

    2002-01-01

    The City of Norman operated a solid-waste municipal landfill at two sites on the Canadian River alluvium in Cleveland County, Oklahoma from 1970 to 1985. The sites, referred to as the west and east cells of the landfill, were originally excavations in the unconsolidated alluvial deposits and were not lined. Analysis of ground-water samples indicate that leachate from the west cell is discharging into an adjacent abandoned river channel, referred to as the slough, and is migrating downgradient in ground water toward the Canadian River. The report describes the hydrogeologic features at the landfill, including the topography of the bedrock, water-level changes in the alluvial aquifer, and delineates the leachate plume using specific conductance data. The leading edge of the leachate plume along the 35-80 transect extended over 250 meters downgradient of the west cell. The leading edge of the leachate plume along the 40-SOUTH transect had moved about 60 meters from the west cell in a south-southwesterly direction and had not moved past the slough as of 1997. Specific conductance measurements exceeding 7,000 microsiemens per centimeter at site 40 indicate the most concentrated part of the plume remained in the upper half of the alluvial aquifer adjacent to the west cell. The direction of ground-water flow in the alluvial aquifer surrounding the landfill was generally north-northeast to south-southwest toward the river. However, between the west cell and the slough along the 40-SOUTH transect, head measurements indicate a directional change to the east and southeast toward a channel referred to as the sewage outfall. Near the 35-80 transect, at 0.5 meter below the water table and at the base of the aquifer, the direction of ground-water flow was south-southeast with a gradient of about 30 centimeters per 100 meters. Generally, ground-water levels in the alluvial aquifer were higher during the winter months and lower during summer months, due to a normal decrease in

  6. Groundwater contamination downstream of a contaminant penetration site. II. Horizontal penetration of the contaminant plume

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2002-01-01

    Part I of this study (Rubin, H.; Buddemeier, R.W. Groundwater Contamination Downstream of a Contaminant Penetration Site Part 1: Extension-Expansion of the Contaminant Plume. J. of Environmental Science and Health Part A (in press).) addressed cases, in which a comparatively thin contaminated region represented by boundary layers (BLs) developed within the freshwater aquifer close to contaminant penetration site. However, at some distance downstream from the penetration site, the top of the contaminant plume reaches the top or bottom of the aquifer. This is the location of the "attachment point," which comprises the entrance cross section of the domain evaluated by the present part of the study. It is shown that downstream from the entrance cross section, a set of two BLs develop in the aquifer, termed inner and outer BLs. It is assumed that the evaluated domain, in which the contaminant distribution gradually becomes uniform, can be divided into two sections, designated: (a) the restructuring section, and (b) the establishment section. In the restructuring section, the vertical concentration gradient leads to expansion of the inner BL at the expense of the outer BL, and there is almost no transfer of contaminant mass between the two layers. In the establishment section, each of the BLs occupies half of the aquifer thickness, and the vertical concentration gradient leads to transfer of contaminant mass from the inner to the outer BL. By use of BL approximations, changes of salinity distribution in the aquifer are calculated and evaluated. The establishment section ends at the uniformity point, downstream from which the contaminant concentration profile is practically uniform. The length of the restructuring section, as well as that of the establishment section, is approximately proportional to the aquifer thickness squared, and is inversely proportional to the transverse dispersivity. The study provides a convenient set of definitions and terminology that are

  7. Contaminant plumes containment and remediation focus area. Technology summary

    SciTech Connect

    1995-06-01

    EM has established a new approach to managing environmental technology research and development in critical areas of interest to DOE. The Contaminant Plumes Containment and Remediation (Plumes) Focus Area is one of five areas targeted to implement the new approach, actively involving representatives from basic research, technology implementation, and regulatory communities in setting objectives and evaluating results. This document presents an overview of current EM activities within the Plumes Focus Area to describe to the appropriate organizations the current thrust of the program and developing input for its future direction. The Plumes Focus Area is developing remediation technologies that address environmental problems associated with certain priority contaminants found at DOE sites, including radionuclides, heavy metals, and dense non-aqueous phase liquids (DNAPLs). Technologies for cleaning up contaminants of concern to both DOE and other federal agencies, such as volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), and other organics and inorganic compounds, will be developed by leveraging resources in cooperation with industry and interagency programs.

  8. Contamination control and plume assessment of low-energy thrusters

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1993-01-01

    Potential contamination of a spacecraft cryogenic surface by a xenon (Xe) ion generator was evaluated. The analysis involves the description of the plume exhausted from the generator with its relative component fluxes on the spacecraft surfaces, and verification of the conditions for condensation, adsorption, and sputtering at those locations. The data describing the plume fluxes and their effects on surfaces were obtained from two sources: the tests carried out with the Xe generator in a small vacuum chamber to indicate deposits and sputter on monitor slides; and the extensive tests with a mercury (Hg) ion thruster in a large vacuum chamber. The Hg thruster tests provided data on the neutrals, on low-energy ion fluxes, on high-energy ion fluxes, and on sputtered materials at several locations within the plume.

  9. Superposition of borehole-to-surface voltage residuals for Vadose Zone plume delineation.

    PubMed

    Osiensky, James L; Belknap, Willard J; Donaldson, Paul R

    2006-01-10

    An injected tracer field experiment was conducted at the University of Idaho Ground Water Field Laboratory to evaluate the application of borehole-to-surface voltage measurements for delineation of the tracer distribution in partially saturated, fractured basalt. A tap water tracer was injected into a fracture-dominated, salt-water plume formed during a previous salt-water injection experiment. The tap water tracer was injected into a central injection well under constant hydraulic head for 34 days. The injection well was surrounded by seven test boreholes. Each borehole contained several copper wire electrodes for borehole-to-surface potential measurements between a surface grid of 224 copper sulfate, porous pot electrodes. Eight pole-pole, borehole-to-surface voltage data sets were acquired during each measurement period by energization of a selected electrode in each of the eight boreholes. Predicted voltages for a uniform earth (homogeneous and isotropic) potential model (finite difference) were subtracted from each data set (for its respective current source location), and the voltage residuals superposed to create new data sets with greater measurement sensitivity and coverage, to aid in interpretation. These data sets were collected over four measurement periods during tap water injection and four measurement periods during the subsequent 64-day drainage phase. The data were interpreted with the use of three-dimensional models and by comparisons with other electrical and hydrological observations. Results indicate that superposition of multiple data sets of voltage residuals significantly improved the lateral resolution of subsurface bulk resistivity changes that occurred over time. PMID:16298016

  10. Chaotic Advection, Fluid Spreading, and Groundwater Contaminant Plumes

    NASA Astrophysics Data System (ADS)

    Neupauer, R. M.; Mays, D. C.

    2011-12-01

    In situ remediation of contaminated groundwater requires degradation reactions at the interface between the contaminant plume and an injected treatment solution containing chemical or biological amendments. Therefore a promising approach to accelerate in situ remediation is to elongate the interface between the contaminant plume and treatment solution through fluid spreading. The literature on chaotic advection describes how to accomplish spreading in laminar flows, which lack the turbulent eddies that provide spreading in streams or engineered reactors. A key result from the literature on chaotic advection is that spreading is inherent in the vicinity of certain periodic points, which are points to which fluid particles return in successive iterations of chaotic flows. Specifically, spreading is enhanced near the stable and unstable manifolds associated with hyperbolic periodic points. We investigate the transient flow created with a four-well system in which wells are operated sequentially as either injection wells or extraction wells. In particular, we identify the periodic points and demonstrate that fluid spreading occurs nearby. For appropriately designed injection and extraction sequences, the periodic points are located near the interface between the contaminant plume and treatment solution, leading to elongation of the interface, with expected benefits of enhanced reaction and accelerated remediation.

  11. Hall Effect Thruster Plume Contamination and Erosion Study

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.

    2000-01-01

    The objective of the Hall effect thruster plume contamination and erosion study was to evaluate the impact of a xenon ion plume on various samples placed in the vicinity of a Hall effect thruster for a continuous 100 hour exposure. NASA Glenn Research Center was responsible for the pre- and post-test evaluation of three sample types placed around the thruster: solar cell cover glass, RTV silicone, and Kapton(R). Mass and profilometer), were used to identify the degree of deposition and/or erosion on the solar cell cover glass, RTV silicone, and Kapton@ samples. Transmittance, reflectance, solar absorptance, and room temperature emittance were used to identify the degree of performance degradation of the solar cell cover glass samples alone. Auger spectroscopy was used to identify the chemical constituents found on the surface of the exposed solar cell cover glass samples. Chemical analysis indicated some boron nitride contamination on the samples, from boron nitride insulators used in the body of the thruster. However, erosion outweighted contamination. All samples exhibited some degree of erosion. with the most erosion occurring near the centerline of the plume and the least occurring at the +/- 90 deg positions. For the solar cell cover glass samples, erosion progressed through the antireflective coating and into the microsheet glass itself. Erosion occurred in the solar cell cover glass, RTV silicone and Kapton(R) at different rates. All optical properties changed with the degree of erosion, with solar absorptance and room temperature emittance increasing with erosion. The transmittance of some samples decreased while the reflectance of some samples increased and others decreased. All results are consistent with an energetic plume of xenon ions serving as a source for erosion.

  12. Delineating Landfill Leachate Discharge To An Arsenic Contaminated Waterway

    EPA Science Inventory

    Discharge of contaminated ground water may serve as a primary and on-going source of contamination to surface water. A field investigation was conducted at a Superfund site in Massachusetts, USA to define the locus of contaminant flux and support source identification for arseni...

  13. Shuttle PRCS plume contamination analysis for Astro-2 mission

    NASA Technical Reports Server (NTRS)

    Wang, Francis C.; Greene, Cindy

    1993-01-01

    The Astro-2 mission scheduled for Jan. 1995 flight is co-manifested with the Spartan experiment. The Astro instrument array consists of several telescopes operating in the UV spectrum. To obtain the desired 300 observations with the telescope array in a shorter time than the Astro-1 mission, it will be necessary to use the primary reaction control system (PRCS) rather than just the Vernier reaction control system. The high mass flow rate of the PRCS engines cause considerable concern about contamination due to PRCS plume return flux. Performance of these instruments depends heavily on the environment they encounter. The ability of the optical system to detect a remote signal depends not only on the intensity of the incoming signal, but also on the ensuing transmission loss through the optical train of the instrument. Performance of these instruments is thus dependent on the properties of the optical surface and the medium through which it propagates. The on-orbit contamination environment will have a strong influence on the performance of these instruments. The finding of a two-month study of the molecular contamination environment of the Astro-2 instruments due to PRCS thruster plumes during the planned Astro-2 mission are summarized.

  14. Simple indicator kriging for estimating the probability of incorrectly delineating hazardous areas in a contaminated site

    SciTech Connect

    Juang, K.W.; Lee, D.Y.

    1998-09-01

    The probability of incorrectly delineating hazardous areas in a contaminated site is very important for decision-makers because it indicates the magnitude of confidence that decision-makers have in determining areas in need of remediation. In this study, simple indicator kriging (SIK) was used to estimate the probability of incorrectly delineating hazardous areas in a heavy metal-contaminated site, which is located at Taoyuan, Taiwan, and is about 10 ha in area. In the procedure, the values 0 and 1 were assigned to be the stationary means of the indicator codes in the SIK model to represent two hypotheses, hazardous and safe, respectively. The spatial distribution of the conditional probability of heavy metal concentrations lower than a threshold, given each hypothesis, was estimated using SIK. Then, the probabilities of false positives ({alpha}) (i.e., the probability of declaring a location hazardous when it is not) and false negatives ({beta}) (i.e., the probability of declaring a location safe when it is not) in delineating hazardous areas for the heavy metal-contaminated site could be obtained. The spatial distribution of the probabilities of false positives and false negatives could help in delineating hazardous areas based on a tolerable probability level of incorrect delineation. In addition, delineation complicated by the cost of remediation, hazards in the environment, and hazards to human health could be made based on the minimum values of {alpha} and {beta}. The results suggest that the proposed SIK procedure is useful for decision-makers who need to delineate hazardous areas in a heavy metal-contaminated site.

  15. IDENTIFYING AND PREDICTING DIVING PLUME BEHAVIOR AT GROUNDWATER SITES CONTAMINATED WITH MTBE: PART 2

    EPA Science Inventory

    As contaminant ground water flows downgradient from a release point, its movement is dictated by site geological conditions and hydraulics that may result in significant perpendicular contamination migration. This vertical migration pattern has been termed 'plume diving'. Under ...

  16. Groundwater redox conditions and conductivity in a contaminant plume from geoelectrical investigations

    NASA Astrophysics Data System (ADS)

    Naudet, V.; Revil, A.; Rizzo, E.; Bottero, J.-Y.; Bégassat, P.

    Accurate mapping of the electrical conductivity and of the redox potential of the groundwater is important in delineating the shape of a contaminant plume. A map of redox potential in an aquifer is indicative of biodegradation of organic matter and of concentrations of redox-active components; a map of electrical conductivity provides information on the mineralisation of the groundwater. Both maps can be used to optimise the position of pumping wells for remediation. The self-potential method (SP) and electrical resistivity tomography (ERT) have been applied to the contaminant plume associated with the Entressen landfill in south-east France. The self-potential depends on groundwater flow (electrokinetic contribution) and redox conditions ("electro-redox" contribution). Using the variation of the piezometric head in the aquifer, the electrokinetic contribution is removed from the SP signals. A good linear correlation (R2=0.85) is obtained between the residual SP data and the redox potential values measured in monitoring wells. This relationship is used to draw a redox potential map of the overall contaminated site. The electrical conductivity of the subsoil is obtained from 3D-ERT analysis. A good linear correlation (R2=0.91) is observed between the electrical conductivity of the aquifer determined from the 3D-ERT image and the conductivity of the groundwater measured in boreholes. This indicates that the formation factor is nearly homogeneous in the shallow aquifer at the scale of the ERT. From this correlation, a map of the pore water conductivity of the aquifer is obtained.

  17. Contaminant plume configuration and movement: an experimental model

    NASA Astrophysics Data System (ADS)

    Alencoao, A.; Reis, A.; Pereira, M. G.; Liberato, M. L. R.; Caramelo, L.; Amraoui, M.; Amorim, V.

    2009-04-01

    The relevance of Science and Technology in our daily routines makes it compulsory to educate citizens who have both scientific literacy and scientific knowledge. These will allow them to be intervening citizens in a constantly changing society. Thus, physical and natural sciences are included in school curricula, both in primary and secondary education, with the fundamental aim of developing in the students the skills, attitudes and knowledge needed for the understanding of the planet Earth and its real problems. On the other hand, teaching in Geosciences is more and more based on practical methodologies which use didactic material, sustaining teachers' pedagogical practices and facilitating students' learning tasks suggested on the syllabus defined for each school level. Themes related to exploring the different components of the Hydrological Cycle and themes related to natural environment protection and preservation, namely water resources and soil contamination by industrial and urban sewage are examples of subject matters included on the Portuguese syllabus. These topics motivated the conception and construction of experimental models for the study of the propagation of pollutants on a porous medium. The experimental models allow inducing a horizontal flux of water though different kinds of permeable substances (e.g. sand, silt), with contamination spots on its surface. These experimental activities facilitate the student to understand the flow path of contaminating substances on the saturated zone and to observe the contaminant plume configuration and movement. The activities are explored in a teaching and learning process perspective where the student builds its own knowledge through real question- problem based learning which relate Science, Technology and Society. These activities have been developed in the framework of project ‘Water in the Environment' (CV/PVI/0854) of the POCTI Program (Programa Operacional "Ciência, Tecnologia, Inovação") financed

  18. Persistence of a Groundwater Contaminant Plume after Hydraulic Source Containment at a Chlorinated-Solvent Contaminated Site

    PubMed Central

    Matthieu, D.E.; Brusseau, M.L.; Guo, Z.; Plaschke, M.; Carroll, K.C.; Brinker, F.

    2015-01-01

    The objective of this study was to characterize the behavior of a groundwater contaminant (trichloroethene) plume after implementation of a source-containment operation at a site in Arizona. The plume resides in a quasi three-layer system comprising a sand/gravel unit bounded on the top and bottom by relatively thick silty clayey layers. The system was monitored for 60 months beginning at start-up in 2007 to measure the change in contaminant concentrations within the plume, the change in plume area, the mass of contaminant removed, and the integrated contaminant mass discharge. Concentrations of trichloroethene in groundwater pumped from the plume extraction wells have declined significantly over the course of operation, as have concentrations for groundwater sampled from 40 monitoring wells located within the plume. The total contaminant mass discharge associated with operation of the plume extraction wells peaked at 0.23 kg/d, decreased significantly within one year, and thereafter began an asymptotic decline to a current value of approximately 0.03 kg/d. Despite an 87% reduction in contaminant mass and a comparable 87% reduction in contaminant mass discharge for the plume, the spatial area encompassed by the plume has decreased by only approximately 50%. This is much less than would be anticipated based on ideal flushing and mass-removal behavior. Simulations produced with a simplified 3-D numerical model matched reasonably well to the measured data. The results of the study suggest that permeability heterogeneity, back diffusion, hydraulic factors associated with the specific well field system, and residual discharge from the source zone are all contributing to the observed persistence of the plume, as well as the asymptotic behavior currently observed for mass removal and for the reduction in contaminant mass discharge. PMID:26069436

  19. INORGANIC PLUME DELINEATION USING SURFACE HIGH RESOLUTION ELECTRICAL RESISTIVITY AT THE BC CRIBS & TRENCHES SITE HANFORD

    SciTech Connect

    BENECKE, M.W.

    2007-05-29

    A surface resistivity survey was conducted on the Hanford Site over a waste disposal trench that received a large volume of liquid inorganic waste. The objective of the survey was to map the extent of the plume that resulted from the disposal activities approximately 50 years earlier. The survey included six resistivity transects of at least 200m, where each transect provided two-dimensional profile information of subsurface electrical properties. The results of the survey indicated that a low resistivity plume resides at a depth of approximately 25-44 m below ground surface. The target depth was calibrated with borehole data of pore-water electrical conductivity. Due to the high correlation of the pore-water electrical conductivity to nitrate concentration and the high correlation of measured apparent resistivity to pore-water electrical conductivity, inferences were made that proposed the spatial distribution of the apparent resistivity was due to the distribution of nitrate. Therefore, apparent resistivities were related to nitrate, which was subsequently rendered in three dimensions to show that the nitrate likely did not reach the water table and the bounds of the highest concentrations are directly beneath the collection of waste sites.

  20. In situ sequential treatment of a mixed contaminant plume

    NASA Astrophysics Data System (ADS)

    Morkin, M.; Devlin, J. F.; Barker, J. F.; Butler, B. J.

    2000-10-01

    Groundwater plumes often contain a mixture of contaminants that cannot easily be remediated in situ using a single technology. The purpose of this research was to evaluate an in situ treatment sequence for the control of a mixed organic plume (chlorinated ethenes and petroleum hydrocarbons) within a Funnel-and-Gate. A shallow plume located in the unconfined aquifer at Alameda Point, CA, was found to contain up to 218,000 μg/l of cis-1,2 dichloroethene (cDCE), 16,000 μg/l of vinyl chloride (VC) and <1000 μg/l of 1,1 dichloroethene (1,1 DCE), trans-1,2 dichloroethene ( trans-1,2 DCE) and trichloroethene (TCE). Total benzene, toluene, ethylbenzene and xylenes (BTEX) concentrations were <10,000 μg/l. Contaminated groundwater was funneled into a gate, 3.0 m wide, 4.5 m long and 6.0 m deep (keyed into the underlying aquitard) where treatment occurred. The initial gate segment consisted of granular iron, for the reductive dechlorination of the higher chlorinated ethenes. The second segment, the biosparge zone, promoted aerobic biodegradation of petroleum hydrocarbons and any remaining lesser-chlorinated compounds, stimulated by dissolved oxygen (DO) and carbon dioxide (CO 2) additions via an in situ sparge system (CO 2 was used to neutralize the high pH produced from reactions in the iron wall). Groundwater was drawn through the gate by pumping two wells located at the sealed, downgradient, end. Over a 4-month period an estimated 1350 g of cDCE flowed into the treatment gate and the iron wall removed 1230 g, or 91% of the mass. The influent mass of VC was 572 g and the iron wall removed 535 g, corresponding to 94% mass removal. The other chlorinated ethenes had significantly lower influent masses (3 to 108 g) and the iron wall removed the majority of the mass resulting in >96% mass removal for any of the compounds. In spite of these high removal percentages, laboratory column tests indicated that at these levels of chlorinated contaminants, surface saturation of the

  1. Delineation of brine contamination in and near the East Poplar oil field, Fort Peck Indian Reservation, northeastern Montana, 2004-09

    USGS Publications Warehouse

    Thamke, Joanna N.; Smith, Bruce D.

    2014-01-01

    The extent of brine contamination in the shallow aquifers in and near the East Poplar oil field is as much as 17.9 square miles and appears to be present throughout the entire saturated zone in contaminated areas. The brine contamination affects 15–37 billion gallons of groundwater. Brine contamination in the shallow aquifers east of the Poplar River generally moves to the southwest toward the river and then southward in the Poplar River valley. The likely source of brine contamination in the shallow aquifers is brine that is produced with crude oil in the East Poplar oil field study area. Brine contamination has not only affected the water quality from privately owned wells in and near the East Poplar oil field, but also the city of Poplar’s public water-supply wells. Three water-quality types characterize water in the shallow aquifers; a fourth water-quality type in the study area characterizes the brine. Type 1 is uncontaminated water that is suitable for most domestic purposes and typically contains sodium bicarbonate and sodium/magnesium sulfate as the dominant ions. Type 2 is moderately contaminated water that is suitable for some domestic purposes, but not used for drinking water, and typically contains sodium and chloride as the dominant ions. Type 3 is considerably contaminated water that is unsuitable for any domestic purpose and always contains sodium and chloride as the dominant ions. Type 3 quality of water in the shallow aquifers is similar to Type 4, which is the brine that is produced with crude oil. Electromagnetic apparent conductivity data were collected in the 106 square-mile area and used to determine extent of brine contamination. These data were collected and interpreted in conjunction with water-quality data collected through 2009 to delineate brine plumes in the shallow aquifers. Monitoring wells subsequently were drilled in some areas without existing water wells to confirm most of the delineated brine plumes; however, several possible

  2. Leachate plume delineation and lithologic profiling using surface resistivity in an open municipal solid waste dumpsite, Sri Lanka.

    PubMed

    Wijesekara, Hasintha Rangana; De Silva, Sunethra Nalin; Wijesundara, Dharani Thanuja De Silva; Basnayake, Bendict Francis Antony; Vithanage, Meththika Suharshini

    2015-01-01

    This study presents the use of direct current resistivity techniques (DCRT) for investigation and characterization of leachate-contaminated subsurface environment of an open solid waste dumpsite at Kandy, Sri Lanka. The particular dumpsite has no liner and hence the leachate flows directly to the nearby river via subsurface and surface channels. For the identification of possible subsurface flow paths and the direction of the leachate, DCRT (two-dimensional, three-dimensional and vertical electrical sounding) have been applied. In addition, the physico-chemical parameters such as pH, electrical conductivity (EC), alkalinity, hardness, chloride, chemical oxygen demand (COD) and total organic carbon (TOC) of leachate collected from different points of the solid waste dumping area and leachate drainage channel were analysed. Resistivity data confirmed that the leachate flow is confined to the near surface and no separate plume is observed in the downstream area, which may be due to the contamination distribution in the shallow overburden thickness. The stratigraphy with leachate pockets and leachate plume movements was well demarcated inside the dumpsite via low resistivity zones (1-3 Ωm). The recorded EC, alkalinity, hardness and chloride contents in leachate were averaged as 14.13 mS cm⁻¹, 3236, 2241 and 320 mg L⁻¹, respectively, which confirmed the possible causes for low resistivity values. This study confirms that DCRT can be effectively utilized to assess the subsurface characteristics of the open dumpsites to decide on corridor placement and depth of permeable reactive barriers to reduce the groundwater contamination. PMID:25209886

  3. The Plume Impingement Contamination II Experiment: Motivation, Design, and Implementation Plan

    NASA Technical Reports Server (NTRS)

    Lumpkin, Forrest E., III; Albyn, Keith C.; Farrell, Thomas L.

    2001-01-01

    The International Space Station (ISS) will have a long service life during which it must be able to serve as a capable platform for a wide variety of scientific investigations. In order to provide this capability, the ISS has, at the system level, a design requirement of no more than 100 Angstroms of contaminant deposition per year from "non-quiescent" sources. Non-quiescent sources include the plumes resulting from the firing of reaction control system (ReS) engines on space vehicles visiting the ISS as well as the engines on the ISS itself. Unfortunately, good general plume contamination models do not yet exist. This is due both to the complexity of the problem, making the analytic approach difficult, and to the difficulty in obtaining empirical measurements of contaminant depositions. To address this lack of flight data, NASA Johnson Space Center is planning to fly an experiment, Plume Impingement Contamination-II, to measure the contamination deposition from the Shuttle Orbiter's primary RCS engines as a function angle from plume centerline. This represents the first direct on-orbit measurement of plume impingement contamination away from the nozzle centerline ever performed, and as such is extremely important in validating mathematical models which will be used to quantify the cumulative plume impingement contamination to the ISS over its lifetime. The paper will elaborate further upon the motivation behind making these measurements as well as present the design and implementation plan of this planned experiment.

  4. Modelling reaction front formation and oscillatory behaviour in a contaminant plume

    NASA Astrophysics Data System (ADS)

    Cribbin, Laura; Fowler, Andrew; Mitchell, Sarah; Winstanley, Henry

    2013-04-01

    Groundwater contamination is a concern in all industrialised countries that suffer countless spills and leaks of various contaminants. Often, the contaminated groundwater forms a plume that, under the influences of regional groundwater flow, could eventually migrate to streams or wells. This can have catastrophic consequences for human health and local wildlife. The process known as bioremediation removes pollutants in the contaminated groundwater through bacterial reactions. Microorganisms can transform the contaminant into less harmful metabolic products. It is important to be able to predict whether such bioremediation will be sufficient for the safe clean-up of a plume before it reaches wells or lakes. Borehole data from a contaminant plume which resulted from spillage at a coal carbonisation plant in Mansfield, England is the motivation behind modelling the properties of a contaminant plume. In the upper part of the plume, oxygen is consumed and a nitrate spike forms. Deep inside the plume, nitrate is depleted and oscillations of organic carbon and ammonium concentration profiles are observed. While there are various numerical models that predict the evolution of a contaminant plume, we aim to create a simplified model that captures the fundamental characteristics of the plume while being comparable in accuracy to the detailed numerical models that currently exist. To model the transport of a contaminant, we consider the redox reactions that occur in groundwater systems. These reactions deplete the contaminant while creating zones of dominant terminal electron accepting processes throughout the plume. The contaminant is depleted by a series of terminal electron acceptors, the order of which is typically oxygen, nitrate, manganese, iron, sulphate and carbon dioxide. We describe a reaction front, characteristic of a redox zone, by means of rapid reaction and slow diffusion. This aids in describing the depletion of oxygen in the upper part of the plume. To

  5. Combining high resolution vertical gradients and sequence stratigraphy to delineate hydrogeologic units for a contaminated sedimentary rock aquifer system

    NASA Astrophysics Data System (ADS)

    Meyer, Jessica R.; Parker, Beth L.; Arnaud, Emmanuelle; Runkel, Anthony C.

    2016-03-01

    Hydrogeologic units (HGUs), representing subsurface contrasts in hydraulic conductivity, form the basis for all conceptual and numerical models of groundwater flow. However, conventionally, delineation of these units relies heavily on data sets indirect with respect to hydraulic properties. Here, we use the spatial and temporal characteristics of the vertical component of hydraulic gradient (i.e., vertical gradient) as the primary line of evidence for delineating HGUs for Cambrian-Ordovician sedimentary rocks at a site in Dane County, Wisconsin. The site includes a 16 km2 area encompassing a 3 km long mixed organic contaminants plume. The vertical gradients are derived from hydraulic head profiles obtained using high resolution Westbay multilevel systems installed at 7 locations along two, orthogonal 4 km long cross-sections and monitoring to depths between 90 and 146 m with an average of 3-4 monitoring zones per 10 m. These vertical gradient cross-sections reveal 11 laterally extensive HGUs with contrasting vertical hydraulic conductivity (Kv). The position and thickness of the Kv contrasts are consistently associated with sequence stratigraphic features (maximum flooding intervals and sequence boundaries) distinguished at the site using cores and borehole geophysical logs. The same sequence stratigraphic features are also traceable across much of the Cambrian-Ordovician aquifer system of the Midwest US. The vertical gradients and sequence stratigraphy were arrived at independently and when combined provide a hydraulically calibrated sequence stratigraphic framework for the site. This framework provides increased confidence in the precise delineation and description of the nature of HGU contacts in each borehole, reduced uncertainty in interpolation of the HGUs between boreholes, and some capability to predict HGU boundaries and thickness in offsite areas where high resolution hydraulic data sets are not available. Consequently, this HGU conceptual model will

  6. Comparison of three nonparametric kriging methods for delineating heavy-metal contaminated soils

    SciTech Connect

    Juang, K.W.; Lee, D.Y

    2000-02-01

    The probability of pollutant concentrations greater than a cutoff value is useful for delineating hazardous areas in contaminated soils. It is essential for risk assessment and reclamation. In this study, three nonparametric kriging methods [indicator kriging, probability kriging, and kriging with the cumulative distribution function (CDF) of order statistics (CDF kriging)] were used to estimate the probability of heavy-metal concentrations lower than a cutoff value. In terms of methodology, the probability kriging estimator and CDF kriging estimator take into account the information of the order relation, which is not considered in indicator kriging. Since probability kriging has been shown to be better than indicator kriging for delineating contaminated soils, the performance of CDF kriging, which the authors propose, was compared with that of probability kriging in this study. A data set of soil Cd and Pb concentrations obtained from a 10-ha heavy-metal contaminated site in Taoyuan, Taiwan, was used. The results demonstrated that the probability kriging and CDF kriging estimations were more accurate than the indicator kriging estimation. On the other hand, because the probability kriging was based on the cokriging estimator, some unreliable estimates occurred in the probability kriging estimation. This indicated that probability kriging was not as robust as CDF kriging. Therefore, CDF kriging is more suitable than probability kriging for estimating the probability of heavy-metal concentrations lower than a cutoff value.

  7. Nonlinear signal contamination effects for gaseous plume detection in hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Theiler, James; Foy, Bernard R.; Fraser, Andrew M.

    2006-05-01

    When a matched filter is used for detecting a weak target in a cluttered background (such as a gaseous plume in a hyperspectral image), it is important that the background clutter be well-characterized. A statistical characterization can be obtained from the off-plume pixels of a hyperspectral image, but if on-plume pixels are inadvertently included, then that background characterization will be contaminated. In broad area search scenarios, where detection is the central aim, it is by definition unknown which pixels in the scene are off-plume, so some contamination is inevitable. In general, the contaminated background degrades the ability of the matched-filter to detect that signal. This could be a practical problem in plume detection. A linear analysis suggests that the effect is limited, and actually vanishes in some cases. In this study, we take into account the Beer's Law nonlinearity of plume absorption, and we investigate the effect of that nonlinearity on the signal contamination.

  8. Delineation of Hydrocarbon Contamination of Soils and Sediments With Environmental Magnetic Methods: Laboratory and Field Studies

    NASA Astrophysics Data System (ADS)

    Rijal, M. L.; Appel, E.; Porsch, K.; Kappler, A.; Blaha, U.; Petrovsky, E.

    2008-12-01

    Hydrocarbon contamination of soils and sediments is a worldwide environmental problem. The present research focuses on the study of magnetic properties of hydrocarbon contaminated soils and sediments using environmental magnetic methods both on field sites as well as in laboratory batch experiments. The main objectives of this research are i) to determine a possible application of magnetic proxies for the delineation of organic contamination in soils and sediments and ii) to examine the role of bacteria in changing soil magnetic properties after hydrocarbon contamination. A former oil field and a former military site which are heavily contaminated with hydrocarbons were studied. Additionally, three different types of natural clean soils were investigated in laboratory experiments by simulating hydrocarbon contamination in sterile and microbial active setups. Magnetic properties, soil properties, iron bioavailability, iron redox state and hydrocarbon content of samples were measured. Additionally, magnetic susceptibility (MS) was monitored weekly in laboratory batch set-ups during several months. Results from the field sites showed that there is an increase of MS and a good correlation between MS and hydrocarbon content. A weekly monitored MS result from the laboratory study clearly indicated~~10% change (increase as well as decrease) of initial MS of respective soils only in microbial active set-ups with saturation after a few weeks of experimental period. This depicts that there is a change of MS caused by microbial iron mineral transformation in presence of hydrocarbon contamination in soils. The results from the field study demonstrate that magnetic proxies can be used to localize hydrocarbon contamination. However, more field sites with hydrocarbon contaminated soils and sediments need to be investigated by using environmental magnetic methods for better understanding the factors driving such changes in magnetic properties.

  9. Fate of organic contaminants in the redox zones of a landfill leachate pollution plume (Vejen, Denmark)

    NASA Astrophysics Data System (ADS)

    Lyngkilde, John; Christensen, Thomas H.

    1992-09-01

    Samples from 75 sample locations in a landfill leachate pollution plume reveal a significant disappearance of specific organic compounds (SOC's) within the first 100 m of the plume. Only the herbicide Mecoprop® (MCPP) migrates further. Since sorption and dilution cannot account for the decreasing concentrations, degradation is considered to be the governing process. Non-volatile organic carbon shows a corresponding fate probably acting as a substrate for the microbial processes. The first 20 m of the plume are methanogenic/sulfidogenic, judged on the chemistry of the groundwater, followed by a significant ferrogenic zone exhibiting a substantial capacity to degrade the SOC's. The presence of intermediary products (here an oxidized camphor compound) supports the concept of degradation within the ferrogenic zone. This investigation draws the attention to the significant natural attenuation of organic contaminants and to the so far neglected ferrogenic zone in controlling the fate of organic contaminants in leachate plumes.

  10. Kriging with cumulative distribution function of order statistics for delineation of heavy-metal contaminated soils

    SciTech Connect

    Juang, K.W.; Lee, D.Y.; Hsiao, C.K.

    1998-10-01

    Accurate delineation of contaminated soils is essential for risk assessment and remediation. The probability of pollutant concentrations lower than a cutoff value is more important than the best estimate of pollutant concentrations for unsampled locations in delineating contaminated soils. In this study, a new method, kriging with the cumulative distribution function (CDF) of order statistics (CDF kriging), is introduced and compared with indicator kriging. It is used to predict the probability that extractable concentrations of Zn will be less than a cut-off value for soils to be declared hazardous. The 0.1 M HCl-extractable Zn concentrations of topsoil of a paddy field having an area of about 2000 ha located in Taiwan are used. A comparison of the CDF of order statistics and indicator function transformation shows that the variance and the coefficient of variation (CV) of the CDF of order statistics transformed data are smaller than those of the indicator function transformed data. This suggests that the CDF of order statistics transformation possesses less variability than does the indicator function transformation. In addition, based on cross-validation, CDF kriging is found to reduce the mean squared errors of estimations by about 30% and to reduce the mean kriging variances by about 26% compared with indicator kriging.

  11. Air-Seawater Exchange of Organochlorine Pesticides along the Sediment Plume of a Large Contaminated River.

    PubMed

    Lin, Tian; Guo, Zhigang; Li, Yuanyuan; Nizzetto, Luca; Ma, Chuanliang; Chen, Yingjun

    2015-05-01

    Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources. PMID:25827140

  12. Isotopic Systematics (U, nitrate and Sr) of the F-Area Acidic Contamination Plume at the Savannah River Site: Clues to Contaminant History and Mobility

    NASA Astrophysics Data System (ADS)

    Christensen, J. N.; Conrad, M. E.; Bill, M.; Denham, M.; Wan, J.; Rakshit, S.; Stringfellow, W. T.; Spycher, N.

    2010-12-01

    Seepage basins in the F-Area of the Savannah River Site were used from 1955 to 1989 for the disposal of low-level radioactive acidic (ave. pH ˜2.9) waste solutions from site operations involving irradiated uranium billets and other materials used in the production of radionuclides. These disposal activities resulted in a persistent acidic groundwater plume (pH as low as 3.2) beneath the F-Area including contaminants such as tritium, nitrate, 90Sr, 129I and uranium and that has impinged on surface water (Four Mile Branch) about 600 m from the basins. After cessation of disposal in 1989, the basins were capped in 1991. Since that time, remediation has consisted of a pump-and-treat system that has recently been replaced with in situ treatment using a funnel-and-gate system with injection of alkaline solutions in the gates to neutralize pH. In order to delineate the history of contamination and the current mobility and fate of contaminants in F-Area groundwater, we have undertaken a study of variations in the isotopic compositions of U (234U/238U, 235U/238U, 236U/238U), Sr (87Sr/86Sr) and nitrate (δ15N, δ18O) within the contaminant plume. This data can be used to trace U transport within the plume, evaluate chemical changes of nitrate, and potentially track plume/sediment chemical interaction and trace the migration of 90Sr. We have analyzed a suite of groundwater samples from monitoring wells, as well as pore-water samples extracted from aquifer sediment cores to map out the isotopic variation within the plume. The isotopic compositions of U from well samples and porewater samples are all consistent with the variable burn-up of depleted U. The variation in U isotopic composition requires at least three different endmembers, without any significant influence of background natural U. The δ15N and δ18O of nitrate from F-Area plume groundwater are distinct both from natural and unaltered synthetic nitrate, and likely represents fractionation due to waste volume

  13. An application of geoelectrical methods for contamination plume recognition in Urbanowice waste disposal

    NASA Astrophysics Data System (ADS)

    Mycka, Mateusz; Mendecki, Maciej Jan

    2013-09-01

    The purpose of this work was to detect groundwater pollution and to identify the conditions of soil and groundwater near the Urbanowice landfill site using geoelectrical measurements. Presented measurements are preliminary results from tested site and are beginning of continuous monitoring. Contamination outflows detected by resistivity and IP technique show a good correlation with available hydrological data. Contamination plume were found in Eastern part of survey profil.

  14. Hydrogeological factors affecting the multiple plumes of chlorinated contaminants in an industrial complex, Wonju, Korea

    NASA Astrophysics Data System (ADS)

    Yang, J.; Kaown, D.; Lee, H.; Lee, K.

    2010-12-01

    Apparent plume attenuations of multiple chlorinated contaminants such as TCE, carbon tetrachloride, and its daughter products at an industrial complex, Wonju, Korea were examined through various hydraulic tests and six rounds of groundwater quality analyses. Aquifer media properties and hydrogeologic factors affecting the distribution and attenuation of multiple contaminants were investigated and key attributes were evaluated. The study area has vertically heterogeneous properties from top alluvial layer to crystalline rocks while the weathered fractured layer above intact Jurassic biotite granite acts as the main layer for groundwater flow and aqueous phase multiple contaminants migration. Aerial heterogeneity in surface conditions plays an important role for groundwater recharge because the industrial complex is mostly paved by asphalt and concrete. Due to limited recharge area and concentrated precipitation in summer season, seasonal effects of contaminant plume distribution diminish as the distance increase from the area of recharge. This study analyzed how differently the solute and contaminant concentrations response to the seasonal recharge. For the analyses, the study site was divided into three zones and four transects were established. Groundwater and solute mass balances were estimated by computing groundwater and solute mass flux through transects. The effects of groundwater pumping, groundwater flow and contaminant degradation were examined to simulate the solutes and contaminant concentrations. General tendency of the water quality and contaminant concentration were reproducible with the effects of major components such as groundwater recharge, pumping and estimated degradation rate.

  15. The Relationship Between Partial Contaminant Source Zone Remediation and Groundwater Plume Attenuation

    NASA Astrophysics Data System (ADS)

    Falta, R. W.

    2004-05-01

    Analytical solutions are developed that relate changes in the contaminant mass in a source area to the behavior of biologically reactive dissolved contaminant groundwater plumes. Based on data from field experiments, laboratory experiments, numerical streamtube models, and numerical multiphase flow models, the chemical discharge from a source region is assumed to be a nonlinear power function of the fraction of contaminant mass removed from the source zone. This function can approximately represent source zone mass discharge behavior over a wide range of site conditions ranging from simple homogeneous systems, to complex heterogeneous systems. A mass balance on the source zone with advective transport and first order decay leads to a nonlinear differential equation that is solved analytically to provide a prediction of the time-dependent contaminant mass discharge leaving the source zone. The solution for source zone mass discharge is coupled semi-analytically with a modified version of the Domenico (1987) analytical solution for three-dimensional reactive advective and dispersive transport in groundwater. The semi-analytical model then employs the BIOCHLOR (Aziz et al., 2000; Sun et al., 1999) transformations to model sequential first order parent-daughter biological decay reactions of chlorinated ethenes and ethanes in the groundwater plume. The resulting semi-analytic model thus allows for transient simulation of complex source zone behavior that is fully coupled to a dissolved contaminant plume undergoing sequential biological reactions. Analyses of several realistic scenarios show that substantial changes in the ground water plume can result from the partial removal of contaminant mass from the source zone. These results, however, are sensitive to the nature of the source mass reduction-source discharge reduction curve, and to the rates of degradation of the primary contaminant and its daughter products in the ground water plume. Aziz, C.E., C.J. Newell, J

  16. Analysis of the remediation systems on the contaminant plume at the Plainville landfill

    SciTech Connect

    Woodworth, R.L.

    1999-06-01

    The Plainville landfill, located in Plainville, Massachusetts, has been the subject of study by several groups in recent years. A contaminant plume, exiting from the southwest corner of the landfill, is contaminating the groundwater downgradient and may affect drinking water wells located there. A two-phase remediation scheme, consisting of an interim overburden air sparging system and a final proposed pump and treat and air sparging system, has been proposed to mitigate the groundwater contaminant plume. This thesis assesses these remediation systems to determine their ability to remediate the contaminants in the groundwater plume. The interim and final proposed air sparging systems were analyzed using existing quarterly reports and a literature review. A MODFLOW groundwater flow model was used to analyze the pump and treat system. These analyses were then compared to the model utilized to design the remediation scheme. Several discrepancies in the design of the remediation scheme were noted as a result of this analysis. First, the presence of till lenses throughout the remediation zone was not addressed. Also, the extraction of water from the competent bedrock layer appears counterproductive. In addition, the air sparging system was not field tested to ascertain the flow pattern in the subsurface. Finally, the installation of the bedrock air sparging wells appears redundant. These discrepancies, however, will only decrease the projected efficiency of the proposed remediation schemes and increase clean up time. Consequently, the results of this study seem to indicate that the proposed remediation scheme is adequately designed.

  17. Testing of stack-unit/aquifer sensitivity analysis using contaminant plume distribution in the subsurface of Savannah River Site, South Carolina, USA

    USGS Publications Warehouse

    Rine, J.M.; Shafer, J.M.; Covington, E.; Berg, R.C.

    2006-01-01

    Published information on the correlation and field-testing of the technique of stack-unit/aquifer sensitivity mapping with documented subsurface contaminant plumes is rare. The inherent characteristic of stack-unit mapping, which makes it a superior technique to other analyses that amalgamate data, is the ability to deconstruct the sensitivity analysis on a unit-by-unit basis. An aquifer sensitivity map, delineating the relative sensitivity of the Crouch Branch aquifer of the Administrative/Manufacturing Area (A/M) at the Savannah River Site (SRS) in South Carolina, USA, incorporates six hydrostratigraphic units, surface soil units, and relevant hydrologic data. When this sensitivity map is compared with the distribution of the contaminant tetrachloroethylene (PCE), PCE is present within the Crouch Branch aquifer within an area classified as highly sensitive, even though the PCE was primarily released on the ground surface within areas classified with low aquifer sensitivity. This phenomenon is explained through analysis of the aquifer sensitivity map, the groundwater potentiometric surface maps, and the plume distributions within the area on a unit-by- unit basis. The results of this correlation show how the paths of the PCE plume are influenced by both the geology and the groundwater flow. ?? Springer-Verlag 2006.

  18. Improving Modeling of Iodine-129 Groundwater Contamination Plumes Using the System Assessment Capability

    SciTech Connect

    Dirkes, J.; Nichols, W.E.; Wurstner, S.K.

    2004-01-01

    Years of production of radioactive materials at the Hanford Site in southeastern Washington State has resulted in contamination of surface, subsurface, and surface water environments. Cleanup of the site has been aided by various tools, including computer software used to predict contaminant migration in the future and estimate subsequent impacts. The System Assessment Capability (SAC) is a total systems tool designed to simulate the movement of contaminants from all waste sites at Hanford through the vadose zone, the unconfined aquifer, and the Columbia River. Except for iodine-129, most of the contaminants modeled by SAC have acceptably matched field measurements. The two most likely reasons for the inconsistency between the measured field data and SAC modeled predictions are an underestimated inventory and an overestimated sorption value (Kd). Field data tend to be point measurements taken from near the surface of the unconfined aquifer. Thus, the depth of the iodine-129 contamination plume on the site is not well characterized. Geostatistical analyses of the measured data were conducted to determine the mass of iodine-129 for four assumed plume depths within the unconfined aquifer. Several simulations for two different Kd’s using the initial SAC inventory were run to determine the effect of an overestimated sorption value on SAC modeled predictions. The initial SAC inventory was then increased for the two different Kd’s to determine the influence of an underestimated inventory on SAC modeled predictions. It was found that evidence for both an underestimated inventory and for an overestimated sorption value for iodine-129 exist. These results suggest that the Kd for iodine-129 should be reevaluated and that a more complete inventory must be generated in order to more accurately model iodine-129 groundwater contamination plumes that match available field data.

  19. Surface and borehole electromagnetic imaging of conducting contaminant plumes

    SciTech Connect

    Berryman, J. G., LLNL

    1998-07-01

    Electromagnetic induction tomography is a promising new tool for imaging electrical conductivity variations in the earth. The EM source field is produced by induction coil (magnetic dipole) transmitters deployed at the surface or in boreholes. Vertical and horizontal component magnetic field detectors are deployed in other boreholes or on the surface. Sources and receivers are typically deployed in a configuration surrounding the region of interest. The goal of this procedure is to image electrical conductivity variations in the earth, much as x-ray tomography is used to image density variations through cross-sections of the body. Although such EM field techniques have been developed and applied, the algorithms for inverting the magnetic field data to produce the desired images of electrical conductivity have not kept pace. One of the main reasons for the lag in the algorithm development has been the fact that the magnetic induction problem is inherently three dimensional; other imaging methods such as x-ray and seismic can make use of two-dimensional approximations that are not too far from reality, but we do not have this luxury in EM induction tomography. In addition, previous field experiments were conducted at controlled test sites that typically do not have much external noise or extensive surface clutter problems often associated with environmental sites. To use the same field techniques in environments more typical of cleanup sites requires a new set of data processing tools to remove the effects of both noise and clutter. The goal of this project is to join theory and experiment to produce enhanced images of electrically conducting fluids underground, allowing better localization of contaminants and improved planning strategies for the subsequent remediation efforts. After explaining the physical context in more detail, this report will summarize the progress made in the first 18 months of this project: (1) on code development and (2) on field tests of

  20. Emplacement of zero-valent metal for remediation of deep contaminant plumes

    SciTech Connect

    Hubble, D.W.; Gillham, R.W.; Cherry, J.A.

    1997-12-31

    Some groundwater plumes containing chlorinated solvent contaminants are found to be so deep that current in situ remediation technologies cannot be economically applied. Also, source zones are often found to be too deep for removal or inaccessible due to surface features. Plumes emanating from these sources require containment or treatment. Containment technologies are available for shallow sites (< 15 m) and are being developed for greater depths. However, it is important to advance the science of reactive treatment - both for cut off of plumes and to contain and treat source zones. Zero-valent metal technology has been used for remediation of solvent plumes at sites in Canada, the UK and at several industrial and military sites in the USA. To date, all of the plumes treated with zero-valent metal (granular iron) have been at depths less than 15 m. This paper gives preliminary results of research into methods to emplace granular iron at depths in the range of 15 to 60 m. The study included review of available and emerging methods of installing barrier or reactive material and the selection, preliminary design and costing of several methods. The design of a treatment system for a 122 m wide PCE plume that, immediately down gradient from its source, extends from a depth of 24 to 37 m below the ground surface is used as a demonstration site. Both Permeable Reactive Wall and Funnel-and-Gate{trademark} systems were considered. The emplacement methods selected for preliminary design and costing were slurry wall, driven/vibrated beam, deep soil mixing and hydrofracturing injection. For each of these methods, the iron must be slurried for ease of pumping and placement using biodegradable polymer viscosifiers that leave the iron reactive.

  1. Tracking the origin and dispersion of contaminated sediments transported by rivers draining the Fukushima radioactive contaminant plume

    NASA Astrophysics Data System (ADS)

    Lepage, H.; Evrard, O.; Onda, Y.; Chartin, C.; Lefevre, I.; Sophie, A.; Bonte, P.

    2015-03-01

    This study was conducted in several catchments draining the main Fukushima Dai-ichi Power Plant contaminant plume in Fukushima prefecture, Japan. We collected soils and sediment drape deposits (n = 128) and investigated the variation in 137Cs enrichment during five sampling campaigns, conducted every six months, which typically occurred after intense erosive events such as typhoons and snowmelt. We show that upstream contaminated soils are eroded during summer typhoons (June-October) before being exported during the spring snowmelt (March-April). However, this seasonal cycle of sediment dispersion is further complicated by the occurrence of dam releases that may discharge large amounts of contaminants to the coastal plains during the coming years.

  2. Source-term development for a contaminant plume for use by multimedia risk assessment models

    SciTech Connect

    Whelan, Gene ); McDonald, John P. ); Taira, Randal Y. ); Gnanapragasam, Emmanuel K.; Yu, Charley; Lew, Christine S.; Mills, William B.

    1999-12-01

    Multimedia modelers from the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: DOE's Multimedia Environmental Pollutant Assessment System (MEPAS), EPA's MMSOILS, EPA's PRESTO, and DOE's RESidual RADioactivity (RESRAD). These models represent typical analytically, semi-analytically, and empirically based tools that are utilized in human risk and endangerment assessments for use at installations containing radioactive and/or hazardous contaminants. Although the benchmarking exercise traditionally emphasizes the application and comparison of these models, the establishment of a Conceptual Site Model (CSM) should be viewed with equal importance. This paper reviews an approach for developing a CSM of an existing, real-world, Sr-90 plume at DOE's Hanford installation in Richland, Washington, for use in a multimedia-based benchmarking exercise bet ween MEPAS, MMSOILS, PRESTO, and RESRAD. In an unconventional move for analytically based modeling, the benchmarking exercise will begin with the plume as the source of contamination. The source and release mechanism are developed and described within the context of performing a preliminary risk assessment utilizing these analytical models. By beginning with the plume as the source term, this paper reviews a typical process and procedure an analyst would follow in developing a CSM for use in a preliminary assessment using this class of analytical tool.

  3. Numerical Simulation of Ion Thruster Plume Backflow for Spacecraft Contamination Assessment.

    NASA Astrophysics Data System (ADS)

    Samanta Roy, Robie I.

    1995-01-01

    A study is presented of the induced environment produced by an ion thruster, and its interactions with spacecraft. Axisymmetric and fully three-dimensional physical and numerical models of an ion thruster plume are developed and utilized to understand the physical processes involved, as well as to make useful predictions of spacecraft contamination. Components included in the model are primary beam ions, neutral propellant efflux, slow propellant ions created mainly by charge-exchange (CEX) collisions, non-propellant efflux (NPE) such as sputtered molybdenum grid metal, and neutralizing electrons. Primary focus is on the creation and transport of both the CEX propellant ions created from the beam ions and neutral propellant, and charged NPE from the thruster plume into the backflow region. The numerical model utilizes the hybrid plasma particle-in-cell (PIC) method, and the fully three-dimensional implementation is designed for multi -computer environments. Computational results of the CEX ion density and flow angles show good qualitative and quantitative agreement with experimental data. It is shown that the CEX ions created in the beam accelerate outwards and form two distinct energy populations, one with a significant backstreaming component. The effect of the background tank pressure in ground experiments, and the accelerator grid impingement current is examined. The backflow contamination from NASA's current 30 cm xenon ion thruster is investigated over the operating envelope of the thruster, and predictions for space operation are made. Scaling relationships for the backflow previously identified are confirmed. Issues regarding the electron temperature in the plume are explored, and it is shown that backflow contamination increases with electron temperature. Fully three-dimensional results with up to 17.5 million particles are presented. It is shown that the spacecraft geometry plays a strong role in the expansion of the CEX plasma. The contamination from the

  4. Exhaust plume and contamination characteristics of a bipropellant (MMH/N2O4) RCS thruster

    NASA Technical Reports Server (NTRS)

    Spisz, E. W.; Bowman, R. L.; Jack, J. R.

    1973-01-01

    Results are presented for three recent tests in a series of thruster contamination experiments made in liquid helium-cooled environmental facility. The contaminating effects encountered on various materials, surfaces, and components, due to the exhaust products from a 5-pound thrust, bipropellant (MMH/N2O4) thruster are investigated. The angular distribution of plume effects around the periphery of the thruster established by transmittance changes of quartz samples over the wavelength range from 0.2 to 2.0 micrometer is studied, along with mass deposition rates at a specific location measured with a quartz crystal microbalance for three different experiments. Quadrupole mass spectrometer measurements of the exhaust products over the mass number range from 12 to 75; infrared transmittance measurements of contaminated samples for the wavelength range from 2.5 to 15 microns; and infrared transmittance measurements of residue from the thruster nozzle are also considered.

  5. The effect of rocket plume contamination on the optical properties of transmitting and reflecting materials

    NASA Technical Reports Server (NTRS)

    Jack, J. R.; Spisz, E. W.; Cassidy, J. F.

    1971-01-01

    The preliminary results of plume contamination from a 5-pound thrust single-doublet, bipropellant rocket engine on the transmittance of quartz and the reflectance of a silicon monoxide overcoated aluminum mirror are presented. Changes in quartz transmittance were found to be significant and were due to both absorption and scattering effects. Contaminant absorption effects were predominant at the short wavelengths and scattering effects were greatest in the visible wavelengths. Measured changes in mirror reflectance were due primarily to contaminant absorption. Scattering effects were found to be as much as 9 percent of the total reflected energy from the mirror. There were no noticeable chemical or erosion effects on either the quartz or the front surface mirror.

  6. Cost-effective sampling network design for contaminant plume monitoring under general hydrogeological conditions.

    PubMed

    Wu, Jianfeng; Zheng, Chunmiao; Chien, Calvin C

    2005-03-01

    A new simulation-optimization methodology is developed for cost-effective sampling network design associated with long-term monitoring of large-scale contaminant plumes. The new methodology is similar in concept to the one presented by Reed et al. (Reed, P.M., Minsker, B.S., Valocchi, A.J., 2000a. Cost-effective long-term groundwater monitoring design using a genetic algorithm and global mass interpolation. Water Resour. Res. 36 (12), 3731-3741) in that an optimization model based on a genetic algorithm is coupled with a flow and transport simulator and a global mass estimator to search for optimal sampling strategies. However, this study introduces the first and second moments of a three-dimensional contaminant plume as new constraints in the optimization formulation, and demonstrates the proposed methodology through a real-world application. The new moment constraints significantly increase the accuracy of the plume interpolated from the sampled data relative to the plume simulated by the transport model. The plume interpolation approaches employed in this study are ordinary kriging (OK) and inverse distance weighting (IDW). The proposed methodology is applied to the monitoring of plume evolution during a pump-and-treat operation at a large field site. It is shown that potential cost savings up to 65.6% may be achieved without any significant loss of accuracy in mass and moment estimations. The IDW-based interpolation method is computationally more efficient than the OK-based method and results in more potential cost savings. However, the OK-based method leads to more accurate mass and moment estimations. A comparison of the sampling designs obtained with and without the moment constraints points to their importance in ensuring a robust long-term monitoring design that is both cost-effective and accurate in mass and moment estimations. Additional analysis demonstrates the sensitivity of the optimal sampling design to the various coefficients included in the

  7. Cross-shore transport pathways between coastal aquifers and coastal seas: Archetype of a nearshore variable-density contaminant plume

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Bakhtyar, R.; Brovelli, A.; Li, L.; Robinson, C. E.; Xin, P.

    2012-12-01

    On permeable beaches, tides and waves lead to an upper saline plume underneath the beach face in addition to the saltwater wedge. The transport and fate of land-derived chemicals depend on process dynamics at the land-sea interface, which can be examined using a nearshore variable-density contaminant plume. Such a plume can be taken as an archetype, since it includes tracer transport as a special case, or can become unstable if a suitable density contrast is imposed. Using this archetype, we consider three features of coastal aquifers: (i) Dense plumes interact with groundwater to produce features that resemble instabilities but are, instead, distinct features that depend on the flow regime and aquifer geometry. While evident in the laboratory, such features are unlikely to occur in the field. (ii) In oceanic settings, coastal aquifers respond and interact with tides and waves. Simulations confirm that beach morphology and in/exfiltration across the beach face are both linked to wave breaking on short time scales, i.e., linkages between beach morphology and in/exfiltration both reflect their relationship with coastal waves. On longer time scales, tide and wave effects are roughly additive, with tides usually being more important. (iii) The density of inland contaminant plume and the coastal aquifer depth both impact on the distribution of travel times from the contaminant site to the beachface. Tracer plume breakthrough curves resemble a Gaussian distribution, with increasing skewness as the plume density increases.

  8. Assessing Redox Potential and Fluid Conductivity of a Contaminant Plume from Geoelectric Methods

    NASA Astrophysics Data System (ADS)

    Naudet, V.; Revil, A.; Rizzo, E.; Bottero, J.; Begassat, P.

    2003-12-01

    The redox potential and the fluid conductivity of a contaminant plume are two key-parameter to evaluate the plume development and to propose appropriate remediation technologies. we applied geo-electrical methods (self-potential, SP, and electrical resistivity tomography, ERT) to the Entressen landfill site (South-eastern France). From the knowledge of the piezometric head variation of the groundwater, the electrokinetic source is removed from the SP signals measured on the field. Then, a correlation (Rý=0.85) is obtained between the residual SP due to redox effect and the redox potential values measured in monitoring wells. The first-order linear relationship derived from this correlation is finally used to obtain a redox potential map of the overall contaminated site. A correlation (Rý=0.70) is observed between the electrical conductivities determined from the 3D ERT image and the conductivity of the groundwater measured in boreholes. From this correlation a map of the fluid conductivity is obtained. The maps of the redox potential and conductivity of the groundwater are both indicative of the presence of contaminants. The first one is more sensitive to the presence of organic matter and biodegradation. The second one gives information on the mineralization of the groundwater. Both maps can therefore be used to optimise the position of pumping wells for remediation.

  9. Pharmaceuticals and other organic wastewater contaminants within a leachate plume downgradient of a municipal landfill

    USGS Publications Warehouse

    Barnes, Kimberlee K.; Christenson, Scott C.; Kolpin, Dana W.; Focazio, Michael J.; Furlong, Edward T.; Zaugg, Steven D.; Meyer, Michael T.; Barber, Larry B.

    2004-01-01

    Ground water samples collected from the Norman Landfill research site in central Oklahoma were analyzed as part of the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program's national reconnaissance of pharmaceuticals and other organic waste water contaminants (OWCs) in ground water. Five sites, four of which are located downgradient of the landfill, were sampled in 2000 and analyzed for 76 OWCs using four research methods developed by the USGS. OWCs were detected in water samples from all of the sites sampled, with 22 of the 76 OWCs being detected at least once. Cholesterol (a plant and animal steroid), was detected at all five sites and was the only compound detected in a well upgradient of the landfill. N,Ndiethyltoluamide (DEET used in insect repellent) and tri(2-chloroethyl) phosphate (fire-retardant) were detected in water samples from all four sites located within the landfill-derived leachate plume. The sites closest to the landfill had more detections and greater concentrations of each of the detected compounds than sites located farther away. Detection of multiple OWCs occurred in the four sites located within the leachate plume, with a minimum of four and a maximum of 17 OWCs detected. Because the landfill was established in the 1920s and closed in 1985, many compounds detected in the leachate plume were likely disposed of decades ago. These results indicate the potential for long-term persistence and transport of some OWCs in ground water.

  10. Integration of Predicted Atmospheric Contaminant Plumes into ArcView GIS

    SciTech Connect

    Koffman, Larry D.

    2005-10-10

    The Savannah River National Laboratory (SRNL) plays a key role in emergency response scenarios in which there may be a release of atmospheric chemical or radiological contamination at the DOE's Savannah River Site (SRS). Meteorologists at SRNL use a variety of tools to predict the path of the plume and levels of contamination along the path. These predictions are used to guide field teams that take sample measurements for verification. Integration of these predicted plumes as well as field measurements into existing Geographic Information System (GIS) interactive maps provides key additional information for decision makers during an emergency. In addition, having this information in GIS format facilitates sharing the information with other agencies that use GIS. In order to be useful during an emergency, an application for converting predictions or measurements into GIS format must be automated and simple to use. Thus, a key design goal in developing such applications is ease of use. Simple menu selections and intuitive forms with graphical user interfaces are used to accomplish this goal. Applications have been written to convert two different predictive code results into ArcView GIS. Meteorologists at SRNL use the Puff/Plume code, which is tied to real-time wind data, to predict the direction and spread of the atmospheric plume for early assessment. The calculated circular puffs are converted into an ArcView polygon shapefile with attributes for predicted time, dose, and radius of the puff. The meteorologists use the more sophisticated Lagrangian Particle Dispersion Model (LPDM) to predict particle dispersion and deposition. The calculational grid is brought into ArcView as a point shapefile and then interpolated to ARC GRID format using Spatial Analyst. This GRID can then be contoured into a line shapefile, which is easily shared with other agencies. The deposition grid is also automatically contoured for values that correspond to FDA Derived Intervention Levels

  11. Delineating the discharge zone and potential natural attenuation of a chlorinated solvent plume to a gaining lowland river: A multi-scale approach

    NASA Astrophysics Data System (ADS)

    Weatherill, J. J.; Krause, S.; Voyce, K. J.

    2012-04-01

    Chlorinated aliphatic hydrocarbons (CAHs), such as trichloroethene (TCE), are often recalcitrant groundwater pollutants which can form extensive dissolved plumes with the potential to impact on the quality of baseflow to rivers. There is a growing need to evaluate the risk to surface water posed by migrating plumes and the intrinsic potential for natural attenuation along contaminant flow paths through the groundwater/surface water interface (GSI). This study investigates the potential discharge of a poorly defined CAH plume to an accreting section of the River Tern (Shropshire, UK). Groundwater sampling in the area has revealed the presence of TCE (with minor chloroform and carbon tetrachloride) with maximum concentrations discovered at depths of up to 80 m in a number of deep boreholes in an unconfined sandstone aquifer hydraulically connected to the river. We aim to develop a conceptual understanding of spatial patterns of plume discharge at sub-catchment to sediment-scale and assess the potential significance of biogeochemical transformation in the river bed and riparian sediments of a baseflow-dominated lowland river. Concentrations of dissolved CAHs (including the anaerobic metabolites of TCE) were monitored in a reach-scale longitudinal channel network of liquid-liquid passive diffusion samplers, placed in direct contact with the top 10 cm of river bed sediment. Samplers comprised distilled water-filled glass vials capped by a thin (50 μm) film of commercially available LDPE tubing. A long integration time (33 days) was selected for sampler equilibration with in-situ pore water concentrations. Results provided a plan-view reconnaissance survey of TCE distribution in the river bed and indicated tentative core and fringe zones. Spatial connectivity between ground and surface water was mapped by means of an in-situ fibre-optic distributed temperature sensor system deployed in the uppermost 10 cm of sediment spanning the investigated reach. To determine changes

  12. The plume fringe concept - Biodegradation of organic contaminants in subsurface ecosystems

    NASA Astrophysics Data System (ADS)

    Meckenstock, R. U.; Griebler, C.; Anneser, B.; Winderl, C.; Bauer, R.; Lüders, T.; Kellermann, C.; Selesi, D.

    2005-12-01

    The biodegradation of organic pollutants in groundwater systems may be limited by the depletion of essential nutrients or the low number of degraders. However, the main problem seems to be the insufficient mixing of e-donors and e-acceptors. Main degradation activities in contaminant plumes are therefore located at their fringes. In order to investigate the ecology of pollutant-degrading microbes, experiments are carried out (1) in 2D-aquifer model systems and (2) sediment cores were drilled at a former gasworks site and a novel high-resolution multilevel sampling well was installed. (1) To assess the importance of individual abiotic (e.g. mixing, toxicity, nutrients) and biotic (e.g. cell distribution and activity, redox tolerance) parameters for biodegradation under well controlled lab conditions, contaminant plumes are generated in 2D-model systems and subsequently inoculated with aerobic and/or anaerobic bacterial strains to investigate biodegradation in a spatially resolved manner. (2) To recognize limitations of biodegradation in a PAH-contaminated aquifer, sediment cores were taken and, at the same site, a high-resolution multilevel well was installed for frequent groundwater sampling with varying spatial resolution (from cm to m range). In both systems, degradation of contaminants is followed by vertically resolved concentration measurements, compound-specific stable isotope (D/H, 13C/12C) analysis and the identification of signature metabolites. Physical-chemical gradients are resolved by means of microsensors and geochemical sediment and water analysis. The spatial distribution of microbial biomass, individual groups of microbes and the presence of functional genes coding for potential degradation activities are investigated using molecular tools. First results of the work, which is embedded in two current projects, will be discussed.

  13. Detection of contaminant plumes in ground water of Long Island, New York, by electromagnetic terrain-conductivity surveys

    USGS Publications Warehouse

    Mack, Thomas J.; Maus, P.E.

    1986-01-01

    Electromagnetic terrain conductivity surveys were conducted at four landfills in Suffolk county and at an artificial recharge site in Nassau County to assess the feasibility of this technique for detecting contaminant plumes. The technique was successful at three of the landfills; results compared closely with those indicated by specific conductance of water from observation wells on the sites. Data from the three sites for which the technique was successful--the Horseblock Road landfill , the Manorville scavenger waste disposal facility, and the Riverhead landfill--revealed pronounced terrain conductivity anomalies that reflect known contaminant plumes. Plumes at the other two sites--Blydenburgh landfill and the East Meadow artificial recharge site--could not be detected because cultural interferences were too great and, at the Blydenburgh site, depth to water was too great. The interferences included pipelines, utility cables, and traffic. Given favorable conditions, such as high plume conductivity, lack of cultural interferences, and a depth of less than 100 ft to the plume, electromagnetic surveying can provide a rapid means of locating contaminant plumes. (Author 's abstract)

  14. Free-product plume distribution and recovery modeling prediction in a diesel-contaminated volcanic aquifer

    NASA Astrophysics Data System (ADS)

    Hernández-Espriú, Antonio; Martínez-Santos, Pedro; Sánchez-León, Emilio; Marín, Luis E.

    Light non-aqueous phase liquids (LNAPL) represent one of the most serious problems in aquifers contaminated with petroleum hydrocarbons liquids. To design an appropriate remediation strategy it is essential to understand the behavior of the plume. The aim of this paper is threefold: (1) to characterize the fluid distribution of an LNAPL plume detected in a volcanic low-conductivity aquifer (∼0.4 m/day from slug tests interpretation), (2) to simulate the recovery processes of the free-product contamination and (3) to evaluate the primary recovery efficiency of the following alternatives: skimming, dual-phase extraction, Bioslurping and multi-phase extraction wells. The API/Charbeneau analytical model was used to investigate the recovery feasibility based on the geological properties and hydrogeological conditions with a multi-phase (water, air, LNAPL) transport approach in the vadose zone. The modeling performed in this research, in terms of LNAPL distribution in the subsurface, show that oil saturation is 7% in the air-oil interface, with a maximum value of 70% in the capillary fringe. Equilibrium between water and LNAPL phases is reached at a depth of 1.80 m from the air-oil interface. On the other hand, the LNAPL recovery model results suggest a remarkable enhancement of the free-product recovery when simultaneous extra-phase extraction was simulated from wells, in addition to the LNAPL lens. Recovery efficiencies were 27%, 65%, 66% and 67% for skimming, dual-phase extraction, Bioslurping and multi-phase extraction, respectively. During a 3-year simulation, skimmer wells and multi-phase extraction showed the lowest and highest LNAPL recovery rates, with expected values from 207 to 163 and 2305 to 707 l-LNAPL/day, respectively. At a field level we are proposing a well distribution arrangement that alternates pairs of dual-phase well-Bioslurping well. This not only improves the recovery of the free-product plume, but also pumps the dissolve plume and enhances in

  15. GROUND WATER SAMPLING FOR VERTICAL PROFILING OF CONTAMINANTS

    EPA Science Inventory

    Accurate delineation of plume boundaries and vertical contaminant distribution are necessary in order to adequately characterize waste sites and determine remedial strategies to be employed. However, it is important to consider the sampling objectives, sampling methods, and sampl...

  16. Simulation of the effect of remediation on EDB and 1,2-DCA plumes at sites contaminated by leaded gasoline

    NASA Astrophysics Data System (ADS)

    Henderson, James K.; Falta, Ronald W.; Freedman, David L.

    2009-08-01

    An analytical model is used to simulate the effects of partial source removal and plume remediation on ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) plumes at contaminated underground storage tank (UST) sites. The risk posed by EDB, 1,2-DCA, and commingled gasoline hydrocarbons varies throughout the plume over time. Dissolution from the light nonaqueous phase liquid (LNAPL) determines the concentration of each contaminant near the source, but biological decay in the plume has a greater influence as distance downgradient from the source increases. For this reason, compounds that exceed regulatory standards near the source may not in downgradient plume zones. At UST sites, partial removal of a residual LNAPL source mass may serve as a stand alone remedial technique if dissolved concentrations in the source zone are within several orders of magnitude of the applicable government or remedial standards. This may be the case with 1,2-DCA; however, EDB is likely to be found at concentrations that are orders of magnitude higher than its low Maximum Contaminant Level (MCL) of 0.05 μg/L (micrograms per liter). For sites with significant EDB contamination, even when plume remediation is combined with source depletion, significant timeframes may be required to mitigate the impact of this compound. Benzene and MTBE are commonly the focus of remedial efforts at UST sites, but simulations presented here suggest that EDB, and to a lesser extent 1,2-DCA, could be the critical contaminants to consider in the remediation design process at many sites.

  17. Plume mass flow and optical damage distributions for an MMH/N2O4 RCS thruster. [exhaust plume contamination of spacecraft components

    NASA Technical Reports Server (NTRS)

    Spisz, E. W.; Bowman, R. L.; Jack, J. R.

    1973-01-01

    The data obtained from two recent experiments conducted in a continuing series of experiments at the Lewis Research Center into the contamination characteristics of a 5-pound thrust MMH/N2O4 engine are presented. The primary objectives of these experiments were to establish the angular distribution of condensible exhaust products within the plume and the corresponding optical damage angular distribution of transmitting optical elements attributable to this contaminant. The plume mass flow distribution was measured by five quartz crystal microbalances (QCM's) located at the engine axis evaluation. The fifth QCM was located above the engine and 15 deg behind the nozzle exit plane. The optical damage was determined by ex-situ transmittance measurements for the wavelength range from 0.2 to 0.6 microns on 2.54 cm diameter fused silica discs also located at engine centerline elevation. Both the mass deposition and optical damage angular distributions followed the expected trend of decreasing deposition and damage as the angle between sensor or sample and the nozzle axis increased. A simple plume gas flow equation predicted the deposition distribution reasonably well for angles of up to 55 degrees. The optical damage measurements also indicated significant effects at large angles.

  18. Phytoforensics, dendrochemistry, and phytoscreening: new green tools for delineating contaminants from past and present.

    PubMed

    Burken, Joel G; Vroblesky, Don A; Balouet, Jean Christophe

    2011-08-01

    As plants evolved to be extremely proficient in mass transfer with their surroundings and survive as earth's dominant biomass, they also accumulate and store some contaminants from surroundings, acting as passive samplers. Novel applications and analytical methods have been utilized to gain information about a wide range of contaminants in the biosphere soil, water, and air, with information available on both past (dendrochemistry) and present (phytoscreening). Collectively these sampling approaches provide rapid, cheap, ecologically friendly, and overall "green" tools termed "Phytoforensics". PMID:21749088

  19. Resistivity and self-potential tomography applied to groundwater remediation and contaminant plumes: Sandbox and field experiments

    NASA Astrophysics Data System (ADS)

    Mao, D.; Revil, A.; Hort, R. D.; Munakata-Marr, J.; Atekwana, E. A.; Kulessa, B.

    2015-11-01

    Geophysical methods can be used to remotely characterize contaminated sites and monitor in situ enhanced remediation processes. We have conducted one sandbox experiment and one contaminated field investigation to show the robustness of electrical resistivity tomography and self-potential (SP) tomography for these applications. In the sandbox experiment, we injected permanganate in a trichloroethylene (TCE)-contaminated environment under a constant hydraulic gradient. Inverted resistivity tomograms are able to track the evolution of the permanganate plume in agreement with visual observations made on the side of the tank. Self-potential measurements were also performed at the surface of the sandbox using non-polarizing Ag-AgCl electrodes. These data were inverted to obtain the source density distribution with and without the resistivity information. A compact horizontal dipole source located at the front of the plume was obtained from the inversion of these self-potential data. This current dipole may be related to the redox reaction occurring between TCE and permanganate and the strong concentration gradient at the front of the plume. We demonstrate that time-lapse self-potential signals can be used to track the kinetics of an advecting oxidizer plume with acceptable accuracy and, if needed, in real time, but are unable to completely resolve the shape of the plume. In the field investigation, a 3D resistivity tomography is used to characterize an organic contaminant plume (resistive domain) and an overlying zone of solid waste materials (conductive domain). After removing the influence of the streaming potential, the identified source current density had a magnitude of 0.5 A m-2. The strong source current density may be attributed to charge movement between the neighboring zones that encourage abiotic and microbially enhanced reduction and oxidation reactions. In both cases, the self-potential source current density is located in the area of strong resistivity

  20. COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FIELD EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (EPA/600/S-99/001)

    EPA Science Inventory

    The major hypothesis driving this research, that the transport of colloids in a contaminant plume is limited by the advance of the chemical agent causing colloid mobilization, was tested by (1) examining the dependence of colloid transport and mobilization on chemical perturbatio...

  1. Movement and fate of solutes in a plume of sewage-contaminated ground water, Cape Cod, Massachusetts

    USGS Publications Warehouse

    LeBlanc, D. R., (Edited By)

    1984-01-01

    The U.S. Geological Survey (USGS) has begun a nationwide program to study the fate of toxic wastes in groundwater. Several sites where groundwater is known to be contaminated are being studied by interdisciplinary teams of geohydrologists, chemists, and microbiologists. The objective of these studies is to obtain a thorough quantitative understanding of the physical, chemical, and biological processes of contaminant generation, migration, and attenuation in aquifers. One of the sites being studied by the USGS under this program is a plume of sewage contaminated groundwater on Cape Cod, Massachusetts. The plume was formed by land disposal of treated sewage to a glacial outwash aquifer since 1936. This report summarizes results obtained during the first year of research at the Cape Cod s under the USGS Toxic-Waste Ground-Water Contamination Program. The seven papers included in this volume were presented at the Toxic Waste Technical Meeting, Tucson, Arizona, in March 1984. They provide an integrated view of the subsurface distribution of contaminants based on the first year of research and discuss hypotheses concerning the transport processes that affect the movement of contaminants in the plume. (See W89-09053 thru W89-09059) (Lantz-PTT)

  2. Phytoforensics, dendrochemistry, and phytoscreening: New green tools for delineating contaminants from past and present

    USGS Publications Warehouse

    Burken, J.G.; Vroblesky, D.A.; Balouet, J.-C.

    2011-01-01

    As plants evolved to be extremely proficient in mass transfer with their surroundings and survive as earth's dominant biomass, they also accumulate and store some contaminants from surroundings, acting as passive samplers. Novel applications and analytical methods have been utilized to gain information about a wide range of contaminants in the biosphere soil, water, and air, with information available on both past (dendrochemistry) and present (phytoscreening). Collectively these sampling approaches provide rapid, cheap, ecologically friendly, and overall "green" tools termed "Phytoforensics". ?? 2011 American Chemical Society.

  3. DELINEATION OF SUBSURFACE HYDROCARBON CONTAMINANT DISTRIBUTION USING A DIRECT PUSH RESISTIVITY METHOD

    EPA Science Inventory

    A direct push resistivity method was evaluated as a complementary screening tool to provide rapid in-situ contaminant detection to aid in better defining locations for drilling, sampling, and monitoring well installation at hazardous waste sites. Nine continuous direct push resi...

  4. Biodegradation Processes in a Laboratory-Scale Groundwater Contaminant Plume Assessed by Fluorescence Imaging and Microbial Analysis▿

    PubMed Central

    Rees, Helen C.; Oswald, Sascha E.; Banwart, Steven A.; Pickup, Roger W.; Lerner, David N.

    2007-01-01

    Flow reactors containing quartz sand colonized with biofilm were set up as physical model aquifers to allow degrading plumes of acetate or phenol to be formed from a point source. A noninvasive fluorescent tracer technique was combined with chemical and biological sampling in order to quantify transport and biodegradation processes. Chemical analysis of samples showed a substantial decrease in carbon concentration between the injection and outflow resulting primarily from dilution but also from biodegradation. Two-dimensional imaging of the aqueous oxygen [O2(aq)] concentration field quantified the depletion of O2(aq) within the contaminant plume and provided evidence for microbial respiration associated with biodegradation of the carbon source. Combined microbiological, chemical, and O2(aq) imaging data indicated that biodegradation was greatest at the plume fringe. DNA profiles of bacterial communities were assessed by temperature gradient gel electrophoresis, which revealed that diversity was limited and that community changes observed depended on the carbon source used. Spatial variation in activity within the plume could be quantitatively accounted for by the changes observed in active cell numbers rather than differences in community structure, the total biomass present, or the increased enzyme activity of individual cells. Numerical simulations and comparisons with the experimental data were used to test conceptual models of plume processes. Results demonstrated that plume behavior was best described by growth and decay of active biomass as a single functional group of organisms represented by active cell counts. PMID:17468279

  5. Plume-Scale Testing of a Simplified Method for Detecting Tritium Contamination in Plants and Soil

    NASA Astrophysics Data System (ADS)

    Andraski, B. J.; Halford, K. J.; Johnson, M. J.; Michel, R. L.; Radyk, J. C.

    2003-12-01

    Research at the Amargosa Desert Research Site near Beatty, Nevada indicates that tritium movement from a closed low-level radioactive waste facility occurs primarily in the gas phase with preferential transport through coarse-textured sediment layers. However, models for movement of tritiated water vapor at the site fail to predict the extent of transport indicated by field measurements. In order to develop a better understanding of the spatial distribution of tritium contamination in the near-surface environment adjacent to the waste facility, a recently published tritium contamination-detection method was tested for collection and analysis of plume-scale data. The method entails solar distillation of plant water from foliage, followed by filtration and adsorption of scintillation-interfering constituents on a graphite-based solid-phase-extraction column prior to direct-scintillation counting. Samples were collected from 103 plants (creosote bush; Larrea tridentata) within a 72-ha area adjacent to the waste facility. Plant data showed elevated tritium concentrations up to 300 m from the waste facility. For a small ( ˜ 8 ha) area where high-density soil-water vapor data were already available, plant-based and soil-based concentration contours compared favorably. Plant data for previously unmeasured areas identified "hot spots" that were later verified by direct soil measurements. Regression analysis of tritium concentrations from collocated plant- and soil-sampling sites showed that empirical relations could be developed to predict soil concentrations (y) from the more simply determined plant concentrations (x): e.g., the equation for root-zone soil concentrations (Bq/L) was y = 1.156 x + 55.17 (r2 = 0.9521; SEE = 250). Results of this work have improved knowledge of the extent of tritium contamination in the near-surface environment. The pattern of the tritium concentrations indicated that the observed contamination originates from two sources--the waste

  6. Long-term electrical resistivity monitoring of recharge-induced contaminant plume behavior

    NASA Astrophysics Data System (ADS)

    Gasperikova, Erika; Hubbard, Susan S.; Watson, David B.; Baker, Gregory S.; Peterson, John E.; Kowalsky, Michael B.; Smith, Meagan; Brooks, Scott

    2012-11-01

    Geophysical measurements, and electrical resistivity tomography (ERT) data in particular, are sensitive to properties that are related (directly or indirectly) to hydrological processes. The challenge is in extracting information from geophysical data at a relevant scale that can be used to gain insight about subsurface behavior and to parameterize or validate flow and transport models. Here, we consider the use of ERT data for examining the impact of recharge on subsurface contamination at the S-3 ponds of the Oak Ridge Integrated Field Research Challenge (IFRC) site in Tennessee. A large dataset of time-lapse cross-well and surface ERT data, collected at the site over a period of 12 months, is used to study time variations in resistivity due to changes in total dissolved solids (primarily nitrate). The electrical resistivity distributions recovered from cross-well and surface ERT data agrees well, and both of these datasets can be used to interpret spatiotemporal variations in subsurface nitrate concentrations due to rainfall, although the sensitivity of the electrical resistivity response to dilution varies with nitrate concentration. Using the time-lapse surface ERT data interpreted in terms of nitrate concentrations, we find that the subsurface nitrate concentration at this site varies as a function of spatial position, episodic heavy rainstorms (versus seasonal and annual fluctuations), and antecedent rainfall history. These results suggest that the surface ERT monitoring approach is potentially useful for examining subsurface plume responses to recharge over field-relevant scales.

  7. Delineating Fecal Contaminant Sources and Travel Times in a Karst Groundwater Basin, Inner Bluegrass Region, Kentucky

    NASA Astrophysics Data System (ADS)

    Ward, J. W.; Reed, T. M.; Fryar, A. E.; Brion, G. M.

    2006-12-01

    Because of preferential flowpaths via features such as sinkholes and conduits, karst aquifers are susceptible to non-point-source pollution from agricultural and urban drainage. With many karst aquifers being drinking- water sources, pathogens are contaminants of public health concern. Monitoring of microbial parameters (total coliforms [TC], atypical colonies [AC] and fecal coliform bacteria [FC]) transpired biweekly from December 2002 March 2004 and weekly from February October 2005 at Blue Hole Spring, which drains outlying farm lands and the town of Versailles in the Inner Bluegrass Region of Kentucky. Physicochemical parameters (discharge, temperature, specific conductance, and pH) were measured continuously during the entire period. The AC/TC ratio, which had been employed only in surface water-quality studies, was used with FC counts, precipitation and discharge data to determine sources of fecal loading to ground water as result of land-use practices. An AC/TC ratio < 10 demonstrates fresh input of fecal matter, while a larger ratio can represent a variety of occurrences, including aged fecal material input and/or lack of nutrient input into the system. AC/TC ratio data in the 2002 04 dataset behaved similarly to surface waters, with ratios > 10 during dry periods and < 10 during wet periods, while the 2005 data demonstrated a very irregular pattern. The difference in these two data sets indicated a compositional change within the groundwater basin between the two sampling periods, perhaps as a result of construction at a sewage treatment plant adjoining the spring. Solute (rhodamine WT fluorescent dye and bromide) and particle (1-μm diameter fluorescent latex microspheres) tracer tests were conducted during summer 2006 to examine contaminant mobility within the system under base-flow and storm-flow conditions. Rainfall was limited prior to the base-flow trace, totaling 0.025 cm within 2 weeks prior to the slug injection. Base-flow discharge averaged 400 m

  8. In search of plumes: a GPR odyssey in Brazil

    SciTech Connect

    Ulrych, T.J.; Lima, O.A.L. de; Sampaio, E.E.S.

    1994-12-31

    Ground penetrating radar (GPR) and geoelectrical surveys have been combined to outline underground contaminant plumes of industrial origin within a petrochemical center in Bahia, Brazil. Such plumes are invading the upper phreatic layers of a regional aquifer system which is being exploited for supplying cities and villages in the region, for industrial activities and even for the population of Salvador, the third largest city in Brazil. Three case studies are presented: two are related to conductive plumes localized beneath a metallurgical plant and an effluent treatment plant and another, a DNAPL plume below a dirt petrochemical unit. Resistivity soundings and transverse profiling were useful for a gross delineation of the aquifer structure and the extent of the contamination. GPR processed sections were employed for refining the subsurface stratigraphy and petrophysics as well as for a more precise mapping of the plume boundaries.

  9. Insights into biodegradation through depth-resolved microbial community functional and structural profiling of a crude-oil contaminant plume

    USGS Publications Warehouse

    Fahrenfeld, Nicole; Cozzarelli, Isabelle M.; Bailey, Zach; Pruden, Amy

    2014-01-01

    Small-scale geochemical gradients are a key feature of aquifer contaminant plumes, highlighting the need for functional and structural profiling of corresponding microbial communities on a similar scale. The purpose of this study was to characterize the microbial functional and structural diversity with depth across representative redox zones of a hydrocarbon plume and an adjacent wetland, at the Bemidji Oil Spill site. A combination of quantitative PCR, denaturing gradient gel electrophoresis, and pyrosequencing were applied to vertically sampled sediment cores. Levels of the methanogenic marker gene, methyl coenzyme-M reductase A (mcrA), increased with depth near the oil body center, but were variable with depth further downgradient. Benzoate degradation N (bzdN) hydrocarbon-degradation gene, common to facultatively anaerobic Azoarcus spp., was found at all locations, but was highest near the oil body center. Microbial community structural differences were observed across sediment cores, and bacterial classes containing known hydrocarbon degraders were found to be low in relative abundance. Depth-resolved functional and structural profiling revealed the strongest gradients in the iron-reducing zone, displaying the greatest variability with depth. This study provides important insight into biogeochemical characteristics in different regions of contaminant plumes, which will aid in improving models of contaminant fate and natural attenuation rates.

  10. Insights into biodegradation through depth-resolved microbial community functional and structural profiling of a crude-oil contaminant plume.

    PubMed

    Fahrenfeld, Nicole; Cozzarelli, Isabelle M; Bailey, Zach; Pruden, Amy

    2014-10-01

    Small-scale geochemical gradients are a key feature of aquifer contaminant plumes, highlighting the need for functional and structural profiling of corresponding microbial communities on a similar scale. The purpose of this study was to characterize the microbial functional and structural diversity with depth across representative redox zones of a hydrocarbon plume and an adjacent wetland, at the Bemidji Oil Spill site. A combination of quantitative PCR, denaturing gradient gel electrophoresis, and pyrosequencing were applied to vertically sampled sediment cores. Levels of the methanogenic marker gene, methyl coenzyme-M reductase A (mcrA), increased with depth near the oil body center, but were variable with depth further downgradient. Benzoate degradation N (bzdN) hydrocarbon-degradation gene, common to facultatively anaerobic Azoarcus spp., was found at all locations, but was highest near the oil body center. Microbial community structural differences were observed across sediment cores, and bacterial classes containing known hydrocarbon degraders were found to be low in relative abundance. Depth-resolved functional and structural profiling revealed the strongest gradients in the iron-reducing zone, displaying the greatest variability with depth. This study provides important insight into biogeochemical characteristics in different regions of contaminant plumes, which will aid in improving models of contaminant fate and natural attenuation rates. PMID:24760171

  11. Indian MORB-source mantle: not just a case of plume contamination or sediment recycling

    NASA Astrophysics Data System (ADS)

    Kempton, P. D.; Pearce, J. A.

    2003-04-01

    Mid-ocean ridge basalts (MORB) from the Indian Ocean have long been known for their distinctive Pb and Sr isotope compositions relative to other MORBs. Most models for their origin involve contamination of a "normal" depleted mantle by a distinctly enriched material, the most favoured being (1) recycled oceanic crust plus pelagic sediments, (2) mantle plumes and/or (3) delaminated sub-continental lithosphere. Based on quantitative mixing models, Rehkämper and Hofmann (1997) showed that recycling of an old, compositionally heterogeneous component could explain the range of Sr, Nd and Pb isotope compositions for Indian MORBs. Their model predicts that the predominant recycled component is ancient (1.5Ga) altered ocean crust, with pelagic sediment comprising less than 10% of the contaminant. However, Hf-Nd isotope systematics are difficult to explain in this way because Indian MORBs have higher eHf values (i.e. greater time-integrated depletion of Lu relative to Hf) for a given eNd than nearly all other MORBs - and considerably higher than any of the enriched materials suggested as contaminants. Essentially, Indian and Pacific MORBs form separate and parallel arrays in Nd-Hf isotope space. What is required is a mechanism that involves not only enrichment of some elements, but also relative depletion of others. Based on new Nd-Hf isotope data for Indian and Pacific MORBs from the Australian-Antarctic Discordance, we propose that the distinctive Indian MORB source composition can be explained by recycling of subduction-modified mantle. This mantle could have been generated within the convergent margin that existed off the east coast of Gondwana throughout most of the Paleozoic and Mesozoic Eras. It was subsequently recycled into the upper mantle beneath Gondwana and became the source of Indian MORBs following the break-up of the Gondwanan supercontinent. Rehkämper, M., and A. W. Hofmann, Recycled ocean crust and sediment in Indian Ocean MORB, Earth and Planetary

  12. A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site.

    PubMed

    Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

    2013-10-01

    The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in ¹³C (<-60‰) suggesting production lines which have used depleted methane for synthesis. The other source had typical carbon isotope compositions of >-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, ¹³C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas. PMID:24077332

  13. Investigation of contamination of thin-film aluminum filters by MMH-NTO plumes exposed to UV radiation

    NASA Astrophysics Data System (ADS)

    Gupta, Vaibhav; Wieman, Seth; Didkovsky, Leonid; Haiges, Ralf; Yao, Yuhan; Wu, Wei; Gruntman, Mike; Erwin, Dan

    2015-09-01

    Thin-film aluminum filters degrade in space with significant reduction of their Extreme Ultraviolet (EUV) transmission. This degradation was observed on the EUV Spectrophotometer (ESP) onboard the Solar Dynamics Observatory's EUV Variability Experiment and the Solar EUV Monitor (SEM) onboard the Solar and Heliospheric Observatory. One of the possible causes for deterioration of such filters over time is contamination of their surfaces from plumes coming from periodic firing of their satellite's Monomethylhydrazine (MMH) - Nitrogen Tetroxide (NTO) thrusters. When adsorbed by the filters, the contaminant molecules are exposed to solar irradiance and could lead to two possible compositions. First, they could get polymerized leading to a permanent hydrocarbon layer buildup on the filter's surface. Second, they could accelerate and increase the depth of oxidation into filter's bulk aluminum material. To study the phenomena we experimentally replicate contamination of such filters in a simulated environment by MMH-NTO plumes. We apply, Scanning Electron Microscopy and X-Ray photoelectron spectroscopy to characterize the physical and the chemical changes on these contaminated sample filter surfaces. In addition, we present our first analysis of the effects of additional protective layer coatings based on self-assembled carbon monolayers for aluminum filters. This coverage is expected to significantly decrease their susceptibility to contamination and reduce the overall degradation of filter-based EUV instruments over their mission life.

  14. Assessing the Impact of Source-Zone Remediation Efforts at the Contaminant-Plume Scale Through Analysis of Contaminant Mass Discharge

    PubMed Central

    Brusseau, M. L.; Hatton, J.; DiGuiseppi, W.

    2011-01-01

    The long-term impact of source-zone remediation efforts was assessed for a large site contaminated by trichloroethene. The impact of the remediation efforts (soil vapor extraction and in-situ chemical oxidation) was assessed through analysis of plume-scale contaminant mass discharge, which was measured using a high-resolution data set obtained from 23 years of operation of a large pump-and-treat system. The initial contaminant mass discharge peaked at approximately 7 kg/d, and then declined to approximately 2 kg/d. This latter value was sustained for several years prior to the initiation of source-zone remediation efforts. The contaminant mass discharge in 2010, measured several years after completion of the two source-zone remediation actions, was approximately 0.2 kg/d, which is ten times lower than the value prior to source-zone remediation. The time-continuous contaminant mass discharge data can be used to evaluate the impact of the source-zone remediation efforts on reducing the time required to operate the pump-and-treat system, and to estimate the cost savings associated with the decreased operational period. While significant reductions have been achieved, it is evident that the remediation efforts have not completely eliminated contaminant mass discharge and associated risk. Remaining contaminant mass contributing to the current mass discharge is hypothesized to comprise poorly-accessible mass in the source zones, as well as aqueous (and sorbed) mass present in the extensive lower-permeability units located within and adjacent to the contaminant plume. The fate of these sources is an issue of critical import to the remediation of chlorinated-solvent contaminated sites, and development of methods to address these sources will be required to achieve successful long-term management of such sites and to ultimately transition them to closure. PMID:22115080

  15. Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

    SciTech Connect

    Sorenson, Kent S. Jr.

    2003-06-01

    Natural attenuation of TCE under aerobic conditions at the INEEL Test Area North site was demonstrated largely on the basis of preferential loss of TCE relative to conservative solutes (PCE and H-3) along groundwater flow paths. First order degradation half-lives were calculated from the rate of preferential TCE loss. We are utilizing the same approach at other DOE sites that have aerobic TCE plumes to determine if aerobic natural attenuation of TCE is rapid enough at these sites to be environmentally significant, i.e. if natural attenuation can reduce concentrations to acceptable levels before groundwater reaches potential receptors. The first step in this process was to identify TCE plumes at DOE sites that have the appropriate site conditions and data needed to perform this analysis. The site conditions include the presence of TCE in groundwater at appreciable concentrations in an aerobic aquifer, a co-mingled contaminant that can be used as a conservative tracer (e.g. PCE, H-3, Tc-99), a flow path that represents at least a decade of travel time, and several monitoring wells located along this flow path. Candidate sites were identified through interviews with knowledgeable individuals in the DOE system and by screening the U.S. Dept. of Energy Groundwater Database using the keywords ''TCE'' and ''groundwater''. The initial screening yielded 25 plumes for consideration. These sites had anywhere from one to 37 individual plumes containing TCE. Of the 25 sites, 13 sites were further evaluated because they met the screening criteria or were promising. After contacting DOE personnel from the respective sites, they were divided into three groups: (1) sites that meet all the project criteria, (2) sites that could potentially be used for the project, and (3) DOE sites that did not meet the criteria. The five sites with plumes that met the criteria were: Brookhaven National Laboratory, Lawrence Livermore National Laboratory, Paducah Gaseous Diffusion Plant, Rocky Flats

  16. Changes in concentrations of a TCE plume in near- stream zones of a DNAPL contaminated area adjacent to a stream

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    A field investigation of a trichloroethylene (TCE) groundwater plume originating at an industrial complex and its discharges to a stream nearby showed that apparent plume attenuation occurred in the near-stream zone of a DNAPL contaminated area adjacent to a stream prior to discharging to the stream. The concentrations of TCE and cis-1,2-dichloroethene (cis-DCE) in groundwater, hyporheic water, stream water and streambed, and hydrogeology were characterized using mini-piezometers, monitoring wells, Ground Penetrating Radar (GPR) surveys, and soil coring. In the near stream zones temporal and spatial TCE plume concentration changes and mass fluxes were investigated along the flowpath of groundwater discharging to the stream. It is evident that observed concentrations of contaminants (TCE and cis-DCE) were reduced in the near-stream zone, resulting that TCE and cis-DCE were not detected in the streambed and stream water. Ground GPR surveys done in the near stream zone found that wire and water treatment pipe conduits were buried under the ground next to the stream, which could lead groundwater flow field distortion in this zone. At streambed, the GPR survey and soil coring indicated the presence of low permeable zones consisting of rotten material deposits at the top of 0.3 m ~ 0.8 m underlain by silty sands. These hydrogeological features can also attribute to no detection of contaminants in the streambed and stream water because low permeable zone is an obstacle to effective interactions between groundwater and stream water. More investigations will be carried out for comprehensive understanding of hydrological and biogeochemical processes associated with TCE plume attenuation in near stream zones and streambed in the site.

  17. Chromium isotope variation along a contaminated groundwater plume: a coupled Cr(VI)- reduction, advective mixing perspective

    NASA Astrophysics Data System (ADS)

    Bullen, T.; Izbicki, J.

    2007-12-01

    Chromium (Cr) is a common contaminant in groundwater, used in electroplating, leather tanning, wood preservation, and as an anti-corrosion agent. Cr occurs in two oxidation states in groundwater: Cr(VI) is highly soluble and mobile, and is a carcinogen; Cr(III) is generally insoluble, immobile and less toxic than Cr(VI). Reduction of Cr(VI) to Cr(III) is thus a central issue in approaches to Cr(VI) contaminant remediation in aquifers. Aqueous Cr(VI) occurs mainly as the chromate (CrO22-) and bichromate (HCrO2-) oxyanions, while Cr(III) is mainly "hexaquo" Cr(H2O)63+. Cr has four naturally-occurring stable isotopes: 50Cr, 52Cr, 53Cr and 54Cr. When Cr(VI) is reduced to Cr(III), the strong Cr-O bond must be broken, resulting in isotopic selection. Ellis et al. (2002) demonstrated that for reduction of Cr(VI) on magnetite and in natural sediment slurries, the change of isotopic composition of the remnant Cr(VI) pool was described by a Rayleigh fractionation model having fractionation factor ɛCr(VI)-Cr(III) = 3.4‰. We attempted to use Cr isotopes as a monitor of Cr(VI) reduction at a field site in Hinkley, California (USA) where groundwater contaminated with Cr(VI) has been under assessment for remediation. Groundwater containing up to 5 ppm Cr(VI) has migrated down-gradient from the contamination source through the fluvial to alluvial sediments to form a well-defined plume. Uncontaminated groundwater in the aquifer immediately adjacent to the plume has naturally-occurring Cr(VI) of 4 ppb or less (CH2M-Hill). In early 2006, colleagues from CH2M-Hill collected 17 samples of groundwater from within and adjacent to the plume. On a plot of δ53Cr vs. log Cr(VI), the data array is strikingly linear and differs markedly from the trend predicted for reduction of Cr(VI) in the contaminated water. There appear to be two groups of data: four samples with δ53Cr >+2‰ and Cr(VI) <4 ppb, and 13 samples with δ53Cr <+2‰ and Cr(VI) >15 ppb. Simple mixing lines between the

  18. Migration of a groundwater contaminant plume by stratabound flow in Waste Area Grouping 1 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    SciTech Connect

    Ketelle, R.H.; Lee, R.R.

    1992-08-01

    The discovery of radiologically contaminated groundwater in core hole CH-8 in the western portion of Waste Area Grouping (WAG) 1 at Oak Ridge National Laboratory (ORNL) prompted a detailed investigation to identify the contaminant plume. Utilizing a working hypothesis of stratabound groundwater flow and contaminant transport, investigators analyzed existing subsurface geologic data to predict the contaminant plume discharge location in first Creek and locations of contaminated groundwater seepage into storm drains. The hypothesis states that differential lithologic/fracture conditions lead to the development of preferred flow and transport pathways, of discrete vertical extent, which may not be coincident with the hydraulic gradient. Leakage out of the stratabound pathway is a minor component of the overall plume configuration.

  19. Migration of a groundwater contaminant plume by stratabound flow in Waste Area Grouping 1 at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Environmental Restoration Program

    SciTech Connect

    Ketelle, R.H.; Lee, R.R.

    1992-08-01

    The discovery of radiologically contaminated groundwater in core hole CH-8 in the western portion of Waste Area Grouping (WAG) 1 at Oak Ridge National Laboratory (ORNL) prompted a detailed investigation to identify the contaminant plume. Utilizing a working hypothesis of stratabound groundwater flow and contaminant transport, investigators analyzed existing subsurface geologic data to predict the contaminant plume discharge location in first Creek and locations of contaminated groundwater seepage into storm drains. The hypothesis states that differential lithologic/fracture conditions lead to the development of preferred flow and transport pathways, of discrete vertical extent, which may not be coincident with the hydraulic gradient. Leakage out of the stratabound pathway is a minor component of the overall plume configuration.

  20. Hydrazine engine plume contamination mapping. [measuring instruments for rocket exhaust from liquid propellant rocket engines

    NASA Technical Reports Server (NTRS)

    Chirivella, J. E.

    1975-01-01

    Instrumentation for the measurement of plume exhaust specie deposition rates were developed and demonstrated. The instruments, two sets of quartz crystal microbalances, were designed for low temperature operation in the back flow and variable temperature operation in the core flow regions of an exhaust plume. These quartz crystal microbalances performed nominally, and measurements of exhaust specie deposition rates for 8400 number of pulses for a 0.1-lb monopropellant thruster are reported.

  1. Distributional patterns of arsenic concentrations in contaminant plumes offer clues to the source of arsenic in groundwater at landfills

    USGS Publications Warehouse

    Harte, Philip T.

    2015-01-01

    The distributional pattern of dissolved arsenic concentrations from landfill plumes can provide clues to the source of arsenic contamination. Under simple idealized conditions, arsenic concentrations along flow paths in aquifers proximal to a landfill will decrease under anthropogenic sources but potentially increase under in situ sources. This paper presents several conceptual distributional patterns of arsenic in groundwater based on the arsenic source under idealized conditions. An example of advanced subsurface mapping of dissolved arsenic with geophysical surveys, chemical monitoring, and redox fingerprinting is presented for a landfill site in New Hampshire with a complex flow pattern. Tools to assist in the mapping of arsenic in groundwater ultimately provide information on the source of contamination. Once an understanding of the arsenic contamination is achieved, appropriate remedial strategies can then be formulated.

  2. Tracing the dispersion of sediment contaminated with fallout radionuclides along the main rivers draining the contaminated plume in Fukushima Prefecture (Japan)

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Patin, J.; Lefèvre, I.; Chartin, C.; Ayrault, S.; Bonté, Ph.; Onda, Y.

    2012-04-01

    Fukushima Dai-ichi nuclear power plant accident led to the release of important quantities of radionuclides into the environment. Several of those substances (e.g., Cs-134; Cs-137) strongly sorb onto soil particles. Resulting radiations lead to an external exposure threat associated with the spatial distribution of radionuclides. This threat, associated with the possibility of transfer of contamination to plants and direct ingestion of contaminated particles, will affect human activities such as agriculture, forest exploitation and fishing for long periods of time, depending on the half life of the radionuclides (e.g., 2 yrs for Cs-134; 30 yrs for Cs-137). Furthermore, sediment can be a preferential vector of contaminants in rivers, and its transfer can lead to the dispersion of radioactive contamination across larger areas over time. We present here preliminary results obtained during a field campaign conducted in November 2011 in a part of Fukushima Prefecture located in the main contamination plume and covering an area of about 5000 km2. We had the unique opportunity to measure and "trace" the dispersion of sediment contaminated with radionuclides shortly after the catastrophe. In total, 125 soil and sediment samples were collected along the main rivers of the area (i.e., Abukuma, Nitta, Mano, Kutchibuto and Hirose Rivers). This hydrological network drains the contamination plume located 20 to 80 km northwest of Fukushima Dai-ichi power plant. Furthermore, radiation dose rates were measured all throughout the field survey. Preliminary results show that, 8 months after the accident, radiation dose rates constitute a good proxy to trace contamination dispersion in the region, especially along rivers. Radiation dose rates varied between 0.5 µSv/h and 200 µSv/h in the field. Transfer of contaminated sediment has already started in rivers, and it was accelerated by the occurrence of violent typhoons in the region between July and October, 2011. Main gamma

  3. Assessing the natural attenuation of organic contaminants in aquifers using plume-scale electron and carbon balances: model development with analysis of uncertainty and parameter sensitivity

    NASA Astrophysics Data System (ADS)

    Thornton, Steven F.; Lerner, David N.; Banwart, Steven A.

    2001-12-01

    A quantitative methodology is described for the field-scale performance assessment of natural attenuation using plume-scale electron and carbon balances. This provides a practical framework for the calculation of global mass balances for contaminant plumes, using mass inputs from the plume source, background groundwater and plume residuals in a simplified box model. Biodegradation processes and reactions included in the analysis are identified from electron acceptors, electron donors and degradation products present in these inputs. Parameter values used in the model are obtained from data acquired during typical site investigation and groundwater monitoring studies for natural attenuation schemes. The approach is evaluated for a UK Permo-Triassic Sandstone aquifer contaminated with a plume of phenolic compounds. Uncertainty in the model predictions and sensitivity to parameter values was assessed by probabilistic modelling using Monte Carlo methods. Sensitivity analyses were compared for different input parameter probability distributions and a base case using fixed parameter values, using an identical conceptual model and data set. Results show that consumption of oxidants by biodegradation is approximately balanced by the production of CH 4 and total dissolved inorganic carbon (TDIC) which is conserved in the plume. Under this condition, either the plume electron or carbon balance can be used to determine contaminant mass loss, which is equivalent to only 4% of the estimated source term. This corresponds to a first order, plume-averaged, half-life of >800 years. The electron balance is particularly sensitive to uncertainty in the source term and dispersive inputs. Reliable historical information on contaminant spillages and detailed site investigation are necessary to accurately characterise the source term. The dispersive influx is sensitive to variability in the plume mixing zone width. Consumption of aqueous oxidants greatly exceeds that of mineral oxidants

  4. Assessing the natural attenuation of organic contaminants in aquifers using plume-scale electron and carbon balances: model development with analysis of uncertainty and parameter sensitivity.

    PubMed

    Thornton, S F; Lerner, D N; Banwart, S A

    2001-12-15

    A quantitative methodology is described for the field-scale performance assessment of natural attenuation using plume-scale electron and carbon balances. This provides a practical framework for the calculation of global mass balances for contaminant plumes, using mass inputs from the plume source, background groundwater and plume residuals in a simplified box model. Biodegradation processes and reactions included in the analysis are identified from electron acceptors, electron donors and degradation products present in these inputs. Parameter values used in the model are obtained from data acquired during typical site investigation and groundwater monitoring studies for natural attenuation schemes. The approach is evaluated for a UK Permo-Triassic Sandstone aquifer contaminated with a plume of phenolic compounds. Uncertainty in the model predictions and sensitivity to parameter values was assessed by probabilistic modelling using Monte Carlo methods. Sensitivity analyses were compared for different input parameter probability distributions and a base case using fixed parameter values, using an identical conceptual model and data set. Results show that consumption of oxidants by biodegradation is approximately balanced by the production of CH4 and total dissolved inorganic carbon (TDIC) which is conserved in the plume. Under this condition, either the plume electron or carbon balance can be used to determine contaminant mass loss, which is equivalent to only 4% of the estimated source term. This corresponds to a first order, plume-averaged, half-life of > 800 years. The electron balance is particularly sensitive to uncertainty in the source term and dispersive inputs. Reliable historical information on contaminant spillages and detailed site investigation are necessary to accurately characterise the source term. The dispersive influx is sensitive to variability in the plume mixing zone width. Consumption of aqueous oxidants greatly exceeds that of mineral oxidants

  5. On the significance of contaminant plume-scale and dose-response models in defining hydrogeological characterization needs

    NASA Astrophysics Data System (ADS)

    de Barros, F.; Rubin, Y.; Maxwell, R.; Bai, H.

    2007-12-01

    Defining rational and effective hydrogeological data acquisition strategies is of crucial importance since financial resources available for such efforts are always limited. Usually such strategies are developed with the goal of reducing uncertainty, but less often they are developed in the context of the impacts of uncertainty. This paper presents an approach for determining site characterization needs based on human health risk factors. The main challenge is in striking a balance between improved definition of hydrogeological, behavioral and physiological parameters. Striking this balance can provide clear guidance on setting priorities for data acquisition and for better estimating adverse health effects in humans. This paper addresses this challenge through theoretical developments and numerical testing. We will report on a wide range of factors that affect the site characterization needs including contaminant plume's dimensions, travel distances and other length scales that characterize the transport problem, as well as health risk models. We introduce a new graphical tool that allows one to investigate the relative impact of hydrogeological and physiological parameters in risk. Results show that the impact of uncertainty reduction in the risk-related parameters decreases with increasing distances from the contaminant source. Also, results indicate that human health risk becomes less sensitive to hydrogeological measurements when dealing with ergodic plumes. This indicates that under ergodic conditions, uncertainty reduction in human health risk may benefit from better understanding of the physiological component as opposed to a detailed hydrogeological characterization

  6. Application of satellite infrared data for mapping of thermal plume contamination in coastal ecosystem of Korea.

    PubMed

    Ahn, Yu-Hwan; Shanmugam, Palanisamy; Lee, Jae-Hak; Kang, Yong Q

    2006-03-01

    The 5900 MW Younggwang nuclear power station on the west coast of Korea discharges warm water affecting coastal ecology [KORDI report (2003). Wide area observation of the impact of the operation of Younggwang nuclear power plant 5 and 6, No. BSPI 319-00-1426-3, KORDI, Seoul, Korea]. Here the spatial and temporal characteristics of the thermal plume signature of warm water are reported from a time series (1985-2003) of space-borne, thermal infrared data from Landsat and National Oceanic and Atmospheric Administration (NOAA) satellites. Sea surface temperature (SST) were characterized using advanced very high resolution radiometer data from the NOAA satellites. These data demonstrated the general pattern and extension of the thermal plume signature in the Younggwang coastal areas. In contrast, the analysis of SST from thematic mapper data using the Landsat-5 and 7 satellites provided enhanced information about the plume shape, dimension and direction of dispersion in these waters. The thermal plume signature was detected from 70 to 100 km to the south of the discharge during the summer monsoon and 50 to 70 km to the northwest during the winter monsoon. The mean detected plume temperature was 28 degrees C in summer and 12 degrees C in winter. The DeltaT varied from 2 to 4 degrees C in winter and 2 degrees C in summer. These values are lower than the re-circulating water temperature (6-9 degrees C). In addition the temperature difference between tidal flats and offshore (SSTtidal flats - SSToffsore) was found to vary from 5.4 to 8.5 degrees C during the flood tides and 3.5 degrees C during the ebb tide. The data also suggest that water heated by direct solar radiation on the tidal flats during the flood tides might have been transported offshore during the ebb tide. Based on these results we suggest that there is an urgent need to protect the health of Younggwang coastal marine ecosystem from the severe thermal impact by the large quantity of warm water discharged from

  7. Huntington beach shoreline contamination investigation, phase III: coastal circulation and transport patterns : the likelihood of OCSD's plume impacting Huntington beach shoreline

    USGS Publications Warehouse

    Noble, Marlene; Xu, Jingping; Rosenfeld, Leslie; Largier, John; Hamilton, Peter; Jones, Burt; Robertson, George

    2003-01-01

    A consortium of agencies have conducted an extensive investigation of the coastal ocean circulation and transport pathways off Huntington Beach, with the aim of identifying any causal links that may exist between the offshore discharge of wastewater by OCSD and the significant bacterial contamination observed along the Huntington Beach shoreline. This is the third study supported by OCSD to determine possible land-based and coa Although the study identifies several possible coastal ocean pathways by which diluted wastewater may be transported to the beach, including internal tide, sea-breeze and subtidal flow features, there were no direct observations of either the high bacteria concentrations seen in the OCSD plume at the shelf break reaching the shoreline in significant levels or of an association between the existence of a coastal ocean process and beach contamination at or above AB411 levels. It is concluded that the OCSD plume is not a major cause of beach contamination; no causal links could be demonstrated. This conclusion is based on the absence of direct observation of plume-beach links, on analysis of the spatial and temporal patterns of shoreline contamination and coastal ocean processes, and on the observation of higher levels of contamination at the beach than in the plume.

  8. Mercury speciation and mobilization in a wastewater-contaminated groundwater plume

    USGS Publications Warehouse

    Lamborg, Carl H.; Kent, Doug B.; Swarr, Gretchen J.; Munson, Kathleen M.; Kading, Tristan; O'Connor, Alison E.; Fairchild, Gillian M.; LeBlanc, Denis R.; Wiatrowski, Heather A.

    2013-01-01

    We measured the concentration and speciation of mercury (Hg) in groundwater down-gradient from the site of wastewater infiltration beds operated by the Massachusetts Military Reservation, western Cape Cod, Massachusetts. Total mercury concentrations in oxic, mildly acidic, uncontaminated groundwater are 0.5–1 pM, and aquifer sediments have 0.5–1 ppb mercury. The plume of impacted groundwater created by the wastewater disposal is still evident, although inputs ceased in 1995, as indicated by anoxia extending at least 3 km down-gradient from the disposal site. Solutes indicative of a progression of anaerobic metabolisms are observed vertically and horizontally within the plume, with elevated nitrate concentrations and nitrate reduction surrounding a region with elevated iron concentrations indicating iron reduction. Mercury concentrations up to 800 pM were observed in shallow groundwater directly under the former infiltration beds, but concentrations decreased with depth and with distance down-gradient. Mercury speciation showed significant connections to the redox and metabolic state of the groundwater, with relatively little methylated Hg within the iron reducing sector of the plume, and dominance of this form within the higher nitrate/ammonium zone. Furthermore, substantial reduction of Hg(II) to Hg0 within the core of the anoxic zone was observed when iron reduction was evident. These trends not only provide insight into the biogeochemical factors controlling the interplay of Hg species in natural waters, but also support hypotheses that anoxia and eutrophication in groundwater facilitate the mobilization of natural and anthropogenic Hg from watersheds/aquifers, which can be transported down-gradient to freshwaters and the coastal zone.

  9. Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume

    PubMed Central

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lefèvre, Irène; Ayrault, Sophie; Ottlé, Catherine; Bonté, Philippe

    2013-01-01

    Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons to the coastal plains as soon as by November 2011. This export was amplified during snowmelt and typhoons in 2012. In 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. We thereby suggest that storage of contaminated sediment in reservoirs and in coastal sections of the river channels now represents the most crucial issue. PMID:24165695

  10. Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

    SciTech Connect

    Colwell, F. S.; Crawford, R. L.; Sorenson, K.

    2005-09-01

    Acceptance of monitored natural attenuation (MNA) as a preferred treatment technology saves significant site restoration costs for DOE. However, in order to be accepted MNA requires direct evidence of which processes are responsible for the contaminant loss and also the rates of the contaminant loss. Our proposal aims to: 1) provide evidence for one example of MNA, namely the disappearance of the dissolved trichloroethylene (TCE) from the Snake River Plain aquifer (SRPA) at the Idaho National Laboratory’s Test Area North (TAN) site, 2) determine the rates at which aquifer microbes can co-metabolize TCE, and 3) determine whether there are other examples of natural attenuation of chlorinated solvents occurring at DOE sites. To this end, our research has several objectives. First, we have conducted studies to characterize the microbial processes that are likely responsible for the co-metabolic destruction of TCE in the aquifer at TAN (University of Idaho and INL). Second, we are investigating realistic rates of TCE co-metabolism at the low catabolic activities typical of microorganisms existing under aquifer conditions (INL). Using the co-metabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained in the aquifer at TAN and validate the long-term stewardship of this plume. Coupled with the research on low catabolic activities of co-metabolic microbes we are determining the patterns of functional gene expression by these cells, patterns that may be used to diagnose the co-metabolic activity in the SRPA or other aquifers. Third, we have systematically considered the aquifer contaminants at different locations in plumes at other DOE sites in order to determine whether MNA is a broadly applicable remediation strategy for chlorinated hydrocarbons (North Wind Inc.). Realistic terms for co-metabolism of TCE will provide marked improvements in DOE’s ability to predict and

  11. Speciation of iodine isotopes inside and outside of a contaminant plume at the Savannah River Site.

    PubMed

    Schwehr, Kathleen A; Otosaka, Shigeyoshi; Merchel, Silke; Kaplan, Daniel I; Zhang, Saijin; Xu, Chen; Li, Hsiu-Ping; Ho, Yi-Fang; Yeager, Chris M; Santschi, Peter H

    2014-11-01

    A primary obstacle in understanding the fate and transport of the toxic radionuclide (129)I (a thyroid seeker) is an accurate method to distinguish it from the stable isotope, (127)I, and to quantify the various species at environmentally relevant concentrations (~10(-8) M). A pH-dependent solvent extraction and combustion method was paired with accelerator mass spectrometry (AMS) to measure ambient levels of (129)I/(127)I isotope ratios and iodine speciation (iodide (I(-)), iodate (IO3(-)), and organo-I (OI)) in aquatic systems. The method exhibited an overall uncertainty of 10% or less for I(-) and IO3(-), and less than 30% for OI species concentrations and enabled (129)I measurements as low as 0.001 Bq/L (1 Bq/L=10(-13) M). The method was used to analyze groundwater from the Savannah River Site (SRS), South Carolina, USA, along a pH, redox potential (Eh), and organic carbon gradient (8-60 μM DOC). The data confirmed that the (129)I/(127)I ratios and species distribution were strongly pH dependent and varied in a systematic manner from the strongly acidic source. While (129)I speciation in plume samples containing total I concentrations >1.7 Bq/L was similar whether measured by AMS or GC-MS ([I(-)]≫[IO3(-)]=[OI]), AMS enabled (129)I speciation measurements at much lower concentrations than what was possible with GC-MS. AMS analyses demonstrated that groundwater samples minimally impacted by the plume were still orders of magnitude higher than ambient (129)I concentrations typically found elsewhere in the USA groundwaters and rivers. This is likely due to past atmospheric releases of volatile (129)I species by SRS nuclear reprocessing facilities near the study site. Furthermore, the results confirmed the existence of (129)I not only as I(-), but also as OI and IO3(-) species. PMID:25173764

  12. Analytical solutions to dissolved contaminant plume evolution with source depletion during carbon dioxide storage

    NASA Astrophysics Data System (ADS)

    Yang, Yong; Liu, Yongzhong; Yu, Bo; Ding, Tian

    2016-06-01

    Volatile contaminants may migrate with carbon dioxide (CO2) injection or leakage in subsurface formations, which leads to the risk of the CO2 storage and the ecological environment. This study aims to develop an analytical model that could predict the contaminant migration process induced by CO2 storage. The analytical model with two moving boundaries is obtained through the simplification of the fully coupled model for the CO2-aqueous phase -stagnant phase displacement system. The analytical solutions are confirmed and assessed through the comparison with the numerical simulations of the fully coupled model. Then, some key variables in the analytical solutions, including the critical time, the locations of the dual moving boundaries and the advance velocity, are discussed to present the characteristics of contaminant migration in the multi-phase displacement system. The results show that these key variables are determined by four dimensionless numbers, Pe, RD, Sh and RF, which represent the effects of the convection, the dispersion, the interphase mass transfer and the retention factor of contaminant, respectively. The proposed analytical solutions could be used for tracking the migration of the injected CO2 and the contaminants in subsurface formations, and also provide an analytical tool for other solute transport in multi-phase displacement system.

  13. Analytical solutions to dissolved contaminant plume evolution with source depletion during carbon dioxide storage.

    PubMed

    Yang, Yong; Liu, Yongzhong; Yu, Bo; Ding, Tian

    2016-06-01

    Volatile contaminants may migrate with carbon dioxide (CO2) injection or leakage in subsurface formations, which leads to the risk of the CO2 storage and the ecological environment. This study aims to develop an analytical model that could predict the contaminant migration process induced by CO2 storage. The analytical model with two moving boundaries is obtained through the simplification of the fully coupled model for the CO2-aqueous phase -stagnant phase displacement system. The analytical solutions are confirmed and assessed through the comparison with the numerical simulations of the fully coupled model. Then, some key variables in the analytical solutions, including the critical time, the locations of the dual moving boundaries and the advance velocity, are discussed to present the characteristics of contaminant migration in the multi-phase displacement system. The results show that these key variables are determined by four dimensionless numbers, Pe, RD, Sh and RF, which represent the effects of the convection, the dispersion, the interphase mass transfer and the retention factor of contaminant, respectively. The proposed analytical solutions could be used for tracking the migration of the injected CO2 and the contaminants in subsurface formations, and also provide an analytical tool for other solute transport in multi-phase displacement system. PMID:27045163

  14. Using Airborne and Ground Electromagnetic Surveys and DC Resistivity Surveys to Delineate a Plume of Conductive Water at an In-Channel Coalbed Methane Produced Water Impoundment Near the Powder River, Wyoming

    NASA Astrophysics Data System (ADS)

    Lipinski, B. A.; Harbert, W.; Hammack, R.; Sams, J.; Veloski, G.; Smith, B. D.

    2004-12-01

    compared to geological and geochemical data collected from on-site monitoring wells. The geophysical methods accurately delineated the CBM water plume. Differences in the inversion results were observed and are discussed. The AEM data may also prove useful in identifying potential problem areas for locating future in-channel storage impoundments.

  15. Techniques of contributing-area delineation for analysis of nonpoint-source contamination of Long Island, New York

    USGS Publications Warehouse

    Misut, P.

    1995-01-01

    Ninety shallow monitoring wells on Long Island, N.Y., were used to test the hypothesis that the correlation between the detection of volatile organic compounds (VOC's) at a well and explanatory variables representing land use, population density, and hydrogeologic conditions around the well is affected by the size and shape of the area defined as the contributing area. Explanatory variables are quantified through overlay of various specified contributing areas on 1:24 000-scale landuse and population-density geographic information system (GIS) coverages. Four methods of contributing-area delineation were used: (a) centering a circle of selected radius on the well site, (b) orienting a triangular area along the direction of horizontal ground-water flow to the well, (c) generating a shaped based on direction and magnitude of horizontal flow to the well, and (d) generating a shape based on three-dimensional particle pathlines backtracked from the well screen to the water table. The strongest correlations with VOC detections were obtained from circles of 400- to 1 000-meter radius. Improvement in correlation through delineations based on ground-water flow would require geographic overlay on more highly detailed GIS coverages than those used in the study.

  16. A sequential checklist for the assessment of natural attenuation of dissolved petroleum contaminant plumes from leaking underground storage tanks

    SciTech Connect

    De Rose, N.

    1995-12-31

    Estimates of the number of leaking underground storage tanks (UST) are measured in the hundreds of thousands in the United States alone. The discussion in this article largely pertains to the lighter motor fuels which contain aromatic petroleum hydrocarbons. These include benzene, toluene, ethylbenzene and xylenes (BTEX). The occurrence of dissolved BTEX groundwater contaminant plumes is most commonly associated with leaking gasoline USTs. However, their association with other petroleum products is not uncommon. this article and checklist provide guidance for completing UST assessments, which can support the decision-making process presented in the ASTM Emergency Standard Guide. Following the checklist will measure that the initial site assessment results in an accurate and functional characterization of the details and subtleties of the UST Source Impact Zone. This includes evaluating the UST area to identify release pathways for residual contamination in soil and groundwater. Based on the results obtained from the Source Impact Zone Evaluation, natural attenuation can be assessed for its applicability and performance.

  17. Innovative Use of Cr(VI) Plume Depictions and Pump-and-Treat Capture Analysis to Estimate Risks of Contaminant Discharge to Surface Water at Hanford Reactor Areas

    SciTech Connect

    Miller, Chuck W.; Hanson, James P.; Ivarson, Kristine A.; Tonkin, M.

    2015-01-14

    The Hanford Site nuclear reactor operations required large quantities of high-quality cooling water, which was treated with chemicals including sodium dichromate dihydrate for corrosion control. Cooling water leakage, as well as intentional discharge of cooling water to ground during upset conditions, produced extensive groundwater recharge mounds consisting largely of contaminated cooling water and resulted in wide distribution of hexavalent chromium (Cr[VI]) contamination in the unconfined aquifer. The 2013 Cr(VI) groundwater plumes in the 100 Areas cover approximately 6 km2 (1500 acres), primarily in the 100-HR-3 and 100-KR-4 groundwater operable units (OUs). The Columbia River is a groundwater discharge boundary; where the plumes are adjacent to the Columbia River there remains a potential to discharge Cr(VI) to the river at concentrations above water quality criteria. The pump-and-treat systems along the River Corridor are operating with two main goals: 1) protection of the Columbia River, and 2) recovery of contaminant mass. An evaluation of the effectiveness of the pump-and-treat systems was needed to determine if the Columbia River was protected from contamination, and also to determine where additional system modifications may be needed. In response to this need, a technique for assessing the river protection was developed which takes into consideration seasonal migration of the plume and hydraulic performance of the operating well fields. Groundwater contaminant plume maps are generated across the Hanford Site on an annual basis. The assessment technique overlays the annual plume and the capture efficiency maps for the various pump and treat systems. The river protection analysis technique was prepared for use at the Hanford site and is described in detail in M.J. Tonkin, 2013. Interpolated capture frequency maps, based on mapping dynamic water level observed in observation wells and derived water levels in the vicinity of extraction and injection wells

  18. 3-D SPECTRAL IP IMAGING: NON-INVASIVE CHARACTERIZATION OF CONTAMINANT PLUMES

    EPA Science Inventory

    The objective of this study is to develop a noninvasive tomographic imaging technique,based on the spectral induced-polarization method, to characterize the in-situ distribution of organic and inorganic groundwater contaminants. Recent advances in tomographic imaging, applied to ...

  19. Mapping of contaminant plumes with geoelectrical methods. A case study in urban context

    NASA Astrophysics Data System (ADS)

    Vaudelet, P.; Schmutz, M.; Pessel, M.; Franceschi, M.; Guérin, R.; Atteia, O.; Blondel, A.; Ngomseu, C.; Galaup, S.; Rejiba, F.; Bégassat, P.

    2011-12-01

    During the past two decades, the diagnosis and monitoring of polluted sites have become more important. Urban sites are particularly difficult to study, because they are contaminated with various pollutants, and there is a large physical and chemical heterogeneity. The heterogeneity comes from the landfilling of various solid wastes and remolded soil (endogenous or exogenous) from which they were constituted over time. Traditional techniques such as wells monitoring, are often insufficient to evaluate the extension of soil contamination. This is why we proposed a geoelectrical methodology from the fastest to the most information rich technique, showing all carry out and acquisition times: electromagnetic low frequency conductivity mapping, electrical resistivity profiles, chargeability profiles and spectral induced polarization (SIP) soundings. This strategy has been successfully applied to an urban site located in the Paris Basin (France). A conductivity map in relation with geochemical and lithological informations should provide us information to implement electrical resistivity and chargeability profiles. The latter allowed us to differentiate 3 main anomaly zones that have been determined. As interpretation of chargeability profiles is difficult, because it integrates polarization mechanisms with different relaxation times, we add spectral induced polarization soundings that provide us information concerning the contaminant nature. We determined the extension of an organic phase, and of 2 highly mineralized zones that could be linked to biodegraded and/or with pyrite areas. That theory is consistent with groundwater analysis and SIP data. The conclusion is that the suggested methodology is well suited to the study of urban contaminated sites including several different pollutants.

  20. Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

    SciTech Connect

    Colwell, F. S.; Crawford, R. L.; Sorenson, K.

    2005-06-01

    Dissolved dense nonaqueous-phase liquid plumes are persistent, widespread problems in the DOE complex. At the Idaho National Engineering and Environmental Laboratory, dissolved trichloroethylene (TCE) is disappearing from the Snake River Plain aquifer (SRPA) by natural attenuation, a finding that saves significant site restoration costs. Acceptance of monitored natural attenuation as a preferred treatment technology requires direct evidence of the processes and rates of the degradation. Our proposal aims to provide that evidence for one such site by testing two hypotheses. First, we believe that realistic values for in situ rates of TCE cometabolism can be obtained by sustaining the putative microorganisms at the low catabolic activities consistent with aquifer conditions. Second, the patterns of functional gene expression evident in these communities under starvation conditions while carrying out TCE cometabolism can be used to diagnose the cometabolic activity in the aquifer itself. Using the cometabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained at this location and validate the long-term stewardship of this plume. Realistic terms for cometabolism of TCE will provide marked improvements in DOE's ability to predict and monitor natural attenuation of chlorinated organics at other sites, increase the acceptability of this solution, and provide significant economic and health benefits through this noninvasive remediation strategy. Finally, this project aims to derive valuable genomic information about the functional attributes of subsurface microbial communities upon which DOE must depend to resolve some of its most difficult contamination issues.

  1. Compound-specific carbon isotope analysis of a contaminant plume in Kingsford, Michigan, USA

    USGS Publications Warehouse

    Michel, R.L.; Silva, S.R.; Bemis, B.; Godsy, E.M.; Warren, E.

    2001-01-01

    Compound-specific isotope analysis was used to study a contaminated site near Kingsford, Michigan, USA. Organic compounds at three of the sites studied had similar ??13C values indicating that the contaminant source is the same for all sites. At a fourth site, chemical and ??13C values had evolved due to microbial degradation of organics, with the ??13C being much heavier than the starting materials. A microcosm experiment was run to observe isotopic changes with time in the methane evolved and in compounds remaining in the water during degradation. The ??13C values of the methane became heavier during the initial period of the run when volatile fatty acids were being consumed. There was an abrupt decrease in the ??13C values when fatty acids had been consumed and phenols began to be utilized. The ??13C value of the propionate remaining in solution also increased, similar to the results found in the field.

  2. Site characterization and petroleum hydrocarbon plume mapping

    SciTech Connect

    Ravishankar, K.

    1996-12-31

    This paper presents a case study of site characterization and hydrocarbon contamination plume mapping/delineation in a gas processing plant in southern Mexico. The paper describes innovative and cost-effective use of passive (non-intrusive) and active (intrusive) techniques, including the use of compound-specific analytical methods for site characterization. The techniques used, on a demonstrative basis, include geophysical, geochemical, and borehole drilling. Geochemical techniques used to delineate the horizontal extent of hydrocarbon contamination at the site include soil gas surveys. The borehole drilling technique used to assess the vertical extent of contamination and confirm geophysical and geochemical data combines conventional hollow-stem auguring with direct push-probe using Geoprobe. Compound-specific analytical methods, such as hydrocarbon fingerprinting and a modified method for gasoline range organics, demonstrate the inherent merit and need for such analyses to properly characterize a site, while revealing the limitations of noncompound-specific total petroleum hydrocarbon analysis. The results indicate that the techniques used in tandem can properly delineate the nature and extent of contamination at a site; often supplement or complement data, while reducing the risk of errors and omissions during the assessment phase; and provide data constructively to focus site-specific remediation efforts. 7 figs.

  3. Using ASCEM Modeling and Visualization to Inform Stakeholders of Contaminant Plume Evolution and Remediation Efficacy at F-Basin Savannah River, SC – 15156

    SciTech Connect

    Flach, G.; Wainwright, H.; Molins, S.; Davis, J.; Arora, B.; Faybishenko, B.; Krishnan, H.; Hubbard, S.; Flach, G.; Denham, M.; Eddy-Dilek, C.; Moulton, D.; Lipnikov, K.; Gable, C.; Miller, T.; Freshley, M.

    2015-01-28

    Communication with stakeholders, regulatory agencies, and the public is an essential part of implementing different remediation and monitoring activities, and developing site closure strategies at contaminated sites. Modeling of contaminant plume evolution plays a critical role in estimating the benefit, cost, and risk of particular options. At the same time, effective visualization of monitoring data and modeling results are particularly important for conveying the significance of the results and observations. In this paper, we present the results of the Advanced Simulation Capability for Environmental Management (ASCEM) project, including the discussion of the capabilities of newly developed ASCEM software package, along with its application to the F-Area Seepage Basins located in the U.S. Department of Energy Savannah River Site (SRS). ASCEM software includes state-of-the-art numerical methods for simulating complex flow and reactive transport, as well as various toolsets such as a graphical user interface (GUI), visualization, data management, uncertainty quantification, and parameter estimation. Using this software, we have developed an advanced visualization of tritium plume migration coupled with a data management system, and simulated a three-dimensional model of flow and plume evolution on a high-performance computing platform. We evaluated the effect of engineered flow barriers on a nonreactive tritium plume, through advanced plume visualization and modeling of tritium plume migration. In addition, we developed a geochemical reaction network to describe complex geochemical processes at the site, and evaluated the impact of coupled hydrological and geochemical heterogeneity. These results are expected to support SRS’s monitoring activities and operational decisions.

  4. The Oak Ridge Field Research Center : Advancing Scientific Understanding of the Transportation, Fate, and Remediation of Subsurface Contamination Sources and Plumes

    SciTech Connect

    David Watson

    2005-04-18

    Historical research, development, and testing of nuclear materials across this country resulted in subsurface contamination that has been identified at over 7,000 discrete sites across the U.S. Department of Energy (DOE) complex. With the end of the Cold War threat, DOE has shifted its emphasis to remediation, decommissioning, and decontamination of the immense volumes of contaminated groundwater, sediments, and structures at its sites. DOE currently is responsible for remediating 1.7 trillion gallons of contaminated groundwater, an amount equal to approximately four times the daily U.S. water consumption, and 40 million cubic meters of contaminated soil, enough to fill approximately 17 professional sports stadiums.* DOE also sponsors research intended to improve or develop remediation technologies, especially for difficult, currently intractable contaminants or conditions. The Oak Ridge FRC is representative of some difficult sites, contaminants, and conditions. Buried wastes in contact with a shallow water table have created huge reservoirs of contamination. Rainfall patterns affect the water table level seasonally and over time. Further, the hydrogeology of the area, with its fractures and karst geology, affects the movement of contaminant plumes. Plumes have migrated long distances and to surface discharge points through ill-defined preferred flowpaths created by the fractures and karst conditions. From the standpoint of technical effectiveness, remediation options are limited, especially for contaminated groundwater. Moreover, current remediation practices for the source areas, such as capping, can affect coupled processes that, in turn, may affect the movement of subsurface contaminants in unknown ways. Research conducted at the FRC or with FRC samples therefore promotes understanding of the processes that influence the transport and fate of subsurface contaminants, the effectiveness and long-term consequences of extant remediation options, and the

  5. Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon-chlorine isotope analysis and quantitative PCR.

    PubMed

    Hunkeler, Daniel; Abe, Yumiko; Broholm, Mette M; Jeannottat, Simon; Westergaard, Claus; Jacobsen, Carsten Suhr; Aravena, Ramon; Bjerg, Poul L

    2011-01-25

    The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (qPCR) methods targeting Dehaloccocoides sp. and vcrA genes. Redox conditions were characterized as well based on concentrations of dissolved redox sensitive compounds and sulfur isotopes in SO(4)(2-). In the first 400 m downgradient of the source, the plume was confined to the upper 20 m of the aquifer. Further downgradient it widened in vertical direction due to diverging groundwater flow reaching a depth of up to 50 m. As the plume dipped downward and moved away from the source, O(2) and NO(3)(-) decreased to below detection levels, while dissolved Fe(2+) and SO(4)(2-) increased above detectable concentrations, likely due to pyrite oxidation as confirmed by the depleted sulfur isotope signature of SO(4)(2-). In the same zone, PCE and trichloroethene (TCE) disappeared and cis-1,2-dichloroethene (cDCE) became the dominant chlorinated ethene. PCE and TCE were likely transformed by reductive dechlorination rather than abiotic reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of (13)C in the daughter products followed by an enrichment of (13)C as degradation proceeded. At 1000 m downgradient of the source, cDCE was the dominant chlorinated ethene and had reached the source δ(13)C value confirming that cDCE was not affected by abiotic or biotic degradation. Further downgradient (up to 1900 m), cDCE became enriched in (13)C by up to 8 ‰ demonstrating its further transformation while vinylchloride (VC) concentrations remained low (<1 μg/L) and ethene was not observed. The correlated shift of carbon and chlorine isotope ratios of c

  6. Permeable sorptive walls for treatment of hydrophobic organic contaminant plumes in groundwater

    SciTech Connect

    Grathwohl, P.; Peschik, G.

    1997-12-31

    Highly hydrophobic contaminants are easily adsorbed from aqueous solutions. Since for many of these compounds sorption increases with increasing organic carbon content natural materials such as bituminous shales and coals may be used in permeable sorptive walls. This, however, only applies if sorption is at equilibrium, which may not always be the case in groundwater treatment using a funnel-and-gate system. In contrast to the natural solids, granular activated carbons (GACs) have very high sorption capacities and reasonably fast sorption kinetics. The laboratory results show that application of GACs (e.g. F100) is economically feasible for in situ removal of polycyclic aromatic hydrocarbons (PAH) from groundwater at a former manufactured gas plant site (MGP). For less sorbing compounds (such as benzene, toluene, xylenes) a combination of adsorption and biodegradation is necessary (i.e. sorptive + reactive treatment).

  7. Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment

    SciTech Connect

    Colwell, F.S.; Crawford, R.L.; Sorenson, K.

    2005-09-01

    Acceptance of monitored natural attenuation (MNA) as a preferred treatment technology saves significant site restoration costs for DOE. However, in order to be accepted MNA requires direct evidence of which processes are responsible for the contaminant loss and also the rates of the contaminant loss. Our proposal aims to: 1) provide evidence for one example of MNA, namely the disappearance of the dissolved trichloroethylene (TCE) from the Snake River Plain aquifer (SRPA) at the Idaho National Laboratory’s Test Area North (TAN) site, 2) determine the rates at which aquifer microbes can co-metabolize TCE, and 3) determine whether there are other examples of natural attenuation of chlorinated solvents occurring at DOE sites. To this end, our research has several objectives. First, we have conducted studies to characterize the microbial processes that are likely responsible for the co-metabolic destruction of TCE in the aquifer at TAN (University of Idaho and INL). Second, we are investigating realistic rates of TCE co-metabolism at the low catabolic activities typical of microorganisms existing under aquifer conditions (INL). Using the co-metabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained in the aquifer at TAN and validate the long-term stewardship of this plume. Coupled with the research on low catabolic activities of co-metabolic microbes we are determining the patterns of functional gene expression by these cells, patterns that may be used to diagnose the co-metabolic activity in the SRPA or other aquifers.

  8. Detection of fresh ground water and a contaminant plume beneath Red Brook Harbor, Cape Cod, Massachusetts, 2000

    USGS Publications Warehouse

    McCobb, Timothy D.; LeBlanc, Denis R.

    2002-01-01

    Trichloroethene and tetrachloroethene were detected in ground water in a vertical interval from about 68 to 176 feet below sea level beneath the shoreline where the contaminant plume emanating from a capped landfill on the Massachusetts Military Reservation intersects Red Brook Harbor. The highest concentrations at the shoreline, about 15 micrograms per liter of trichloroethene and 1 microgram per liter of tetrachloroethene, were measured in samples from one well at about 176 feet below sea level. The concentrations of nutrients, such as nitrate and ammonium, and trace metals, such as iron and manganese, in these same samples are typical of uncontaminated ground water on Cape Cod. Fresh ground water (bulk electrical conductance less than 100 millisiemens per meter) is present beneath the harbor at 40 of 48 locations investigated within about 250 feet of the shoreline. Fresh ground water also was detected at one location approximately 450 feet from shore. The harbor bottom consists of soft sediments that range in thickness from 0 to greater than 20 feet and overlie sandy aquifer materials. Trichloroethene was detected at several locations in fresh ground water from the sandy aquifer materials beneath the harbor. The highest trichloroethene concentration, about 4.5 micrograms per liter, was measured about 450 feet from shore.

  9. Assessing Contaminant-Removal Conditions and Plume Persistence through Analysis of Data from Long-term Pump-and-Treat Operations

    PubMed Central

    Brusseau, Mark L.; Guo, Zhilin

    2014-01-01

    Historical groundwater-withdrawal and contaminant-concentration data collected from long-term pump-and-treat operations were analyzed and used to examine contaminant mass discharge (CMD) and mass-removal behavior for multiple sites. Differences in behavior were observed, and these differences were consistent with the nature of contaminant distributions and subsurface properties of the sites. For example, while CMD exhibited a relatively rapid decline during the initial stage of operation for all three sites, the rate of decline varied. The greatest rate was observed for the PGN site, whereas the lowest rate was observed for the MOT site. In addition, the MOT site exhibited the lowest relative reduction in CMD. These results are consistent with the actuality that the MOT site likely contains the greatest proportion of poorly accessible contaminant mass, given that it comprises a combined alluvium and fractured-bedrock system in which solvent and dissolved mass are present directly in the bedrock. The relative contributions of the source zones versus the plumes to total CMD were determined. Constrained contaminant mass removal was observed to influence the plumes for all three sites, and was attributed to a combination of uncontrolled (or imperfectly controlled) sources, back diffusion, and well-field hydraulics. The results presented herein illustrate that detailed analysis of operational pump-and-treat data can be a cost-effective method for providing value-added characterization of contaminated sites. PMID:24914523

  10. Source Inversion for contaminant plume dispersion in urban environments using building-resolving simulations

    SciTech Connect

    Chow, F K; Kosovic, B; Chan, S T

    2005-11-04

    Flow in urban environments is complicated by the presence of buildings, which divert the flow into often unexpected directions. Contaminants released at ground level are easily lofted above tall ({approx} 100 m) buildings and channeled through urban canyons that are perpendicular to the wind direction (see e.g., IOP 9 in Chan, 2005). The path of wind and scalars in urban environments is difficult to predict even with building-resolving computational fluid dynamics codes, due to the uncertainty in the synoptic wind and boundary conditions and other errors in the models. Given the difficulties due to the complexity of urban flows, solving an inverse problem becomes quite challenging. That is, given measurements of concentration at sensors scattered throughout a city, is it possible to detect the source of the contaminant? The ability to locate a source and determine its characteristics in a complex environment is necessary for emergency response for accidental or intentional releases of contaminants in densely-populated urban areas. The goal of this work is to demonstrate a robust statistical inversion procedure that performs well even under the complex flow conditions and uncertainty present in urban environments. Much work has previously focused on direct inversion procedures, where an inverse solution is obtained using an adjoint advection-diffusion equation. The exact direct inversion approaches are strictly limited to processes governed by linear equations. In addition, they assume the system is steady-state and that the equations are linear (Enting, 2002). In addition to adjoint models, optimization techniques are also employed to obtain solutions to inverse problems. These techniques often give only a single best answer, or assume a Gaussian distribution to account for uncertainties. General dispersion related inverse problems, however, often include non-linear processes (e.g., dispersion of chemically reacting substances) or are characterized by non

  11. Surface and borehole electromagnetic imaging of conducting contaminant plumes. 1997 annual progress report

    SciTech Connect

    Berryman, J.G.

    1997-01-01

    'Electromagnetic induction tomography is a promising new tool for imaging electrical conductivity variations in the earth. The EM source field is produced by induction coil (magnetic dipole) transmitters deployed at the surface or in boreholes. Vertical and horizontal component magnetic field detectors are deployed in other boreholes or on the surface. Sources and receivers are typically deployed in a configuration surrounding the region of interest. The goal of this procedure is to image electrical conductivity variations in the earth, much as x-ray tomography is used to image density variations through cross-sections of the body. Although such EM field techniques have been developed and applied, the algorithms for inverting the magnetic data to produce the desired images of electrical conductivity have not kept pace. One of the main reasons for the lag in the algorithm development has been the fact that the magnetic induction problem is inherently three dimensional: other imaging methods such as x-ray and seismic can make use of two-dimensional approximations that are not too far from reality, but the author does not have this luxury in EM induction tomography. In addition, previous field experiments were conducted at controlled test sites that typically do not have much external noise or extensive surface clutter problems often associated with environmental sites. To use the same field techniques in environments more typical of cleanup sites requires a new set of data processing tools to remove the effects of both noise and clutter. The goal of this project is to join theory and experiment to produce enhanced images of electrically conducting fluids underground, allowing better localization of contaminants and improved planning strategies for the subsequent remediation efforts. After explaining the physical context in more detail, this report will summarize the progress made in the first year of this project: (1) on code development and (2) on field tests of

  12. Application of environmental tracers to delineate recharge patterns and nitrate contamination in shallow groundwater around a river

    NASA Astrophysics Data System (ADS)

    Kaown, Dugin; Koh, Eunhee; Park, Byeong-Hak; Lee, Kang-Kun

    2016-04-01

    Hydrogeochemical data, stable isotopes, chlorofluorocarbon (CFCs) and 3H-3He in groundwater were applied to characterize residence time, recharge patterns and nitrate contamination of groundwater in a small agricultural area, Yangpyung, Korea. The study area is located around a river and the measured groundwater table ranges from 1.5 to 2.65 m during the year. Most residents in the study area practice agriculture and potato, strawberry, and cabbage are the typical vegetables grown. Vegetable fields are mostly located in the upgradient area of the study area while forest and residence areas are located in the downgradient area. A lot of chemical and organic fertilizers are applied in the upgradient area. The concentration of NO3-N in groundwater showed 9.8-83.7 mg/L in the upgradient area and 0.1-22.6 mg/L in the downgradient area in 2014. It is necessary to monitor groundwater recharge patterns and transport processes of nitrate to protect surface water around the study area. The values of δ18O and δD showed that groundwater is recharged mainly from summer precipitation. The apparent groundwater ages using 3H-3He and CFCs ranged from 13 to 27 years in the upgradient area and from 25 to 35 years in the downgradient area. The NO3-N in more recently recharged groundwater showed higher concentrations while the NO3-N in older groundwater showed low concentrations. Some shallow wells in the downgradient area showed similar apparent groundwater age with that of the river water indicating groundwater-surface water interactions. A conceptual model of groundwater-surface water interactions using stable isotopes, apparent 3H-3He and CFCs age in groundwater will be useful to understand the hydrological processes and nitrate contamination of the study area.

  13. Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment - Task 4: Modeling - Final Report

    SciTech Connect

    Robert C. Starr

    2005-10-31

    Trichloroethene (TCE), a common groundwater contaminant, can be degraded under certain conditions by microorganisms that occur naturally in the subsurface. TCE can be degraded under anaerobic conditions to less chlorinated compounds and ultimately into the non-chlorinated, non-hazardous end product, ethene, via anaerobic reductive dechlorination (ARD). ARD is widely recognized as a TCE degradation mechanism, and occurs in active groundwater remediation and can occur during monitored natural attenuation (MNA). MNA relies on natural processes, such as dispersion and degradation, to reduce contaminant concentrations to acceptable levels without active human intervention other than monitoring. TCE can also be biodegraded under aerobic conditions via cometabolism, in which microbial enzymes produced for other purposes fortuitously also react with TCE. In cometabolism, TCE is oxidized directly to non-hazardous products. Cometabolism as a TCE-degrading process under aerobic conditions is less well known than ARD. Natural attenuation is often discounted as a TCE remedial alternative in aerobic conditions based on the paradigm that TCE is biodegradable only under anaerobic conditions. In contrast to this paradigm, TCE was shown to degrade relative to conservative co-contaminants at an environmentally significant rate in a large (approximately 3 km long) TCE plume in aerobic groundwater at the Idaho National Laboratory (INL), and the degradation mechanism was shown to be cometabolism. MNA was selected as the remedy for most of this plume, resulting in a considerable cost savings relative to conventional remedial methods. To determine if cometabolism might be a viable remedy at other sites with TCE-contaminated aerobic groundwater, TCE plumes at Department of Energy (DOE) facilities were screened to evaluate whether TCE commonly degrades in aerobic groundwater, and if degradation rates are fast enough that natural attenuation could be a viable remedy. One hundred and twenty

  14. Determination of Premining Geochemical Background and Delineation of Extent of Sediment Contamination in Blue Creek Downstream from Midnite Mine, Stevens County, Washington

    USGS Publications Warehouse

    Church, Stanley E.; Kirschner, Frederick E.; Choate, LaDonna M.; Lamothe, Paul J.; Budahn, James R.; Brown, Zoe Ann

    2008-01-01

    geochemical background determined upstream of the mine site. Postmining metal concentrations in sediment are lower than during the mining period, but remain elevated relative to premining geochemical background. Furthermore, the sediment composition of surface sediment in the Blue Creek delta is contaminated. Base-metal contamination by arsenic, cadmium, lead, and zinc in sediment in the delta in Blue Creek cove is dominated by suspended sediment from the Coeur d?Alene mining district. Uranium contamination in surface sediment in the delta of Blue Creek cove extends at least 500 meters downstream from the mouth of Blue Creek as defined by the 1,290-ft elevation boundary between lands administered by the National Park Service and the Spokane Indian Tribe. Comparisons of the premining geochemical background to sediment sampled during the period the mine was in operation, and to the sediment data from the postmining period, are used to delineate the extent of contaminated sediment in Blue Creek cove along the thalweg of Blue Creek into Lake Roosevelt. The extent of contamination out into Lake Roosevelt by mining remains open.

  15. 3-D spectral IP imaging: Non-invasive characterization of contaminant plumes. Annual progress report, September 15, 1996--September 14, 1997

    SciTech Connect

    Frye, K.M.; Lesmes, D.P.; Morgan, F.D.; Rodi, W.; Shi, W.; Sturrock, J.

    1997-12-01

    'The objective of this project is to develop the scientific basis for characterizing contaminant plumes in the earth''s subsurface using field measurements of induced polarization (IP) effects. The first-year accomplishments are (1) laboratory experiments on fluid-saturated sandstones quantifying the dependence of spectral IP responses on solution chemistry and rock micro-geometry; (2) library research on the current understanding of electromagnetic coupling effects on IP data acquired in the field: and (3) development of prototype forward modeling and inversion algorithms for interpreting IP data in terms of 3-D models of complex resistivity.'

  16. Long-Term Distribution and Transport of Nitrate and Ammonium Within a Groundwater Sewage Plume, Cape Cod, MA, After Removal of the Contaminant Source.

    NASA Astrophysics Data System (ADS)

    Repert, D. A.; Smith, R. L.

    2002-12-01

    Disposal of treated sewage for 60 yrs. onto infiltration beds at a site on Cape Cod, MA produced a groundwater contaminant plume >6 km long. The plume was characterized by an anoxic ammonium-containing core, surrounded by an oxic-suboxic outer zone within the sand and gravel aquifer. In Dec. 1995 the sewage treatment facility ceased operation. A long-term study to characterize the distribution of sewage plume constituents was conducted along a 500 m-long transect (source to 3 yrs. groundwater travel distance). Prior to sewage-disposal cessation, total inorganic N within 30 m vertical profiles decreased from 6.6 moles N/m2 (92% NO3-, 8% NH4+) at the point of discharge to 3.3 moles N/m2 (77% NO3-, 23% NH4+) at the furthest point along the transect. Post-cessation nitrate concentrations increased within the first 6 mo. and then gradually decreased. The nitrate decrease was accompanied by an initial nitrite increase, an indication that denitrification was reducing nitrate after the oxygenated sewage discharge was discontinued. There was also an apparent increase in ammonium concentration in the first 6 mo. after cessation. Previous laboratory experiments on pre-cessation cores showed that nitrification was important in converting sorbed ammonium to nitrate under the sewage beds. However, with the removal of the oxygenated sewage source, nitrification ceased, allowing ammonium to initially increase. This increase was correlated with dissolved organic carbon concentrations within the groundwater. Ammonium concentrations decreased dramatically after a year, but subsequently increased in the core of the plume to pre-cessation levels through mineralization of organic N. Recent laboratory core experiments and extractions show that there is a large pool of sorbed organic carbon, although dissolved organic carbon concentrations have been consistently less than 3 mg/L for 6 yrs. Seven yrs. after cessation of the sewage disposal, there is still a significant amount (0.6 moles N

  17. The Impact of In-situ Chemical Oxidation on Contaminant Mass Discharge: Linking Source-Zone and Plume-Scale Characterizations of Remediation Performance

    NASA Astrophysics Data System (ADS)

    Brusseau, M. L.; Carroll, K. C.; Baker, J. B.; Allen, T.; DiGuiseppi, W.; Hatton, J.; Morrison, C.; Russo, A. E.; Berkompas, J. L.

    2011-12-01

    A large-scale permanganate-based in-situ chemical oxidation (ISCO) effort has been conducted over the past ten years at a federal Superfund site in Tucson, AZ, for which trichloroethene (TCE) is the primary contaminant of concern. Remediation performance was assessed by examining the impact of treatment on contaminant mass discharge, an approach that has been used for only a very few prior ISCO projects. Contaminant mass discharge tests were conducted before and after permanganate injection to measure the impact at the source-zone scale. The results indicate that ISCO caused a significant reduction in mass discharge (approximately 75%). The standard approach of characterizing discharge at the source-zone scale was supplemented with additional characterization at the plume scale, which was evaluated by examining the change in contaminant mass discharge associated with the pump-and-treat system. The integrated contaminant mass discharge decreased by approximately 70%, consistent with the source-zone-scale measurements. The integrated mass discharge rebounded from 0.1 to 0.2 Kg/d within one year after cessation of permanganate injections, after which it has been stable for several years. Collection of the integrated contaminant mass discharge data throughout the ISCO treatment period provided a high-resolution, real-time analysis of the site-wide impact of ISCO, thereby linking source-zone remediation to impacts on overall risk. The results indicate that ISCO was successful in reducing contaminant mass discharge at this site, which comprises a highly heterogeneous subsurface environment. Analysis of TCE sediment concentration data for core material collected before and after ISCO supports the hypothesis that the remaining mass discharge is associated in part with poorly-accessible contaminant mass residing within lower-permeability zones.

  18. Impact of In Situ Chemical Oxidation on Contaminant Mass Discharge: Linking Source-Zone and Plume-Scale Characterizations of Remediation Performance

    SciTech Connect

    Brusseau, M. L.; Carroll, Kenneth C.; Allen, Tim J.; Baker, Joseph R.; DiGuiseppi, W.; Hatton, J.; Morrison, C.; Russo, A.; Berkompas, J.

    2011-05-26

    A large-scale permanganate-based in situ chemical oxidation (ISCO) effort has been conducted over the past ten years at a federal Superfund site in Tucson, AZ, for which trichloroethene (TCE) is the primary contaminant of concern. Remediation performance was assessed by examining the impact of treatment on contaminant mass discharge, an approach that has been used for only a very few prior ISCO projects. Contaminant mass discharge tests were conducted before and after permanganate injection to measure the impact at the source-zone scale. The results indicate that ISCO caused a significant reduction in mass discharge (approximately 75%). The standard approach of characterizing discharge at the source-zone scale was supplemented with additional characterization at the plume scale, which was evaluated by examining the change in contaminant mass discharge associated with the pump-and-treat system. The integrated contaminant mass discharge decreased by approximately 70%, consistent with the source-zone-scale measurements. The integrated mass discharge rebounded from 0.1 to 0.2 kg/d within one year after cessation of permanganate injections, after which it has been stable for several years. Collection of the integrated contaminant mass discharge data throughout the ISCO treatment period provided a high-resolution, real-time analysis of the site-wide impact of ISCO, thereby linking source-zone remediation to impacts on overall risk. The results indicate that ISCO was successful in reducing contaminant mass discharge at this site, which comprises a highly heterogeneous subsurface environment. Analysis of TCE sediment concentration data for core material collected before and after ISCO supports the hypothesis that the remaining mass discharge is associated in part with poorly accessible contaminant mass residing within lower permeability zones.

  19. The Impact of In-situ Chemical Oxidation on Contaminant Mass Discharge: Linking Source-Zone and Plume-Scale Characterizations of Remediation Performance

    PubMed Central

    Brusseau, M.L.; Carroll, K.C.; Allen, T.; Baker, J.; DiGuiseppi, W.; Hatton, J.; Morrison, C.; Russo, A.; Berkompas, J.

    2011-01-01

    A large-scale permanganate-based in-situ chemical oxidation (ISCO) effort has been conducted over the past ten years at a federal Superfund site in Tucson, AZ, for which trichloroethene (TCE) is the primary contaminant of concern. Remediation performance was assessed by examining the impact of treatment on contaminant mass discharge, an approach that has been used for only a very few prior ISCO projects. Contaminant mass discharge tests were conducted before and after permanganate injection to measure the impact at the source-zone scale. The results indicate that ISCO caused a significant reduction in mass discharge (approximately 75%). The standard approach of characterizing discharge at the source-zone scale was supplemented with additional characterization at the plume scale, which was evaluated by examining the change in contaminant mass discharge associated with the pump-and-treat system. The integrated contaminant mass discharge decreased by approximately 70%, consistent with the source-zone-scale measurements. The integrated mass discharge rebounded from 0.1 to 0.2 Kg/d within one year after cessation of permanganate injections, after which it has been stable for several years. Collection of the integrated contaminant mass discharge data throughout the ISCO treatment period provided a high-resolution, real-time analysis of the site-wide impact of ISCO, thereby linking source-zone remediation to impacts on overall risk. The results indicate that ISCO was successful in reducing contaminant mass discharge at this site, which comprises a highly heterogeneous subsurface environment. Analysis of TCE sediment concentration data for core material collected before and after ISCO supports the hypothesis that the remaining mass discharge is associated in part with poorly-accessible contaminant mass residing within lower-permeability zones. PMID:21615133

  20. Experimental characterization of a plume of passive contaminant above a thermal source: capture efficiency of a fume extraction hood.

    PubMed

    Devienne, René; Fontaine, Jean Raymond; Kicka, Jérémie; Bonthoux, Francis

    2009-10-01

    Industrial ventilation problems can be linked to the formation of thermal plumes that develop due to natural convection above various heat sources. These plumes, independent of the energy losses and thermal constraints caused, can also be the carrier of polluting products. This article describes an experimental study of the dynamic, thermal, and mass fields that develop from a hot rectangular (0.5 x 1.25 m) horizontal source. The metrology available allows the measurement of not only the local temperatures and velocities but also the concentration of a tracer gas (helium). Mathematical models have been developed enabling representation of the fields concerned; their characterization by isothermal, iso-velocity, or iso-concentration curves; calculation of the flow rate carried by the plume at a given height; calculation of the enthalpy transport; and so on. Moreover, a pollutant capture device has been introduced, and the measurement technique used allows the determination of various efficiencies of practical interest. The ratio of capture flow to free plume flow at a particular height appears to correlate well with the mean efficiencies obtained for distinct source temperatures. PMID:19666957

  1. Investigation of the Strontium-90 Contaminant Plume along the Shoreline of the Columbia River at the 100-N Area of the Hanford Site

    SciTech Connect

    Mendoza, Donaldo P.; Patton, Gregory W.; Hartman, Mary J.; Spane, Frank A.; Sweeney, Mark D.; Fritz, Brad G.; Gilmore, Tyler J.; Mackley, Rob D.; Bjornstad, Bruce N.; Clayton, Ray E.

    2007-10-01

    Efforts are underway to remediate strontium-laden groundwater to the Columbia River at the 100-N Area of the Hanford Site. Past practices of the 100-N reactor liquid waste disposal sites has left strontium-90 sorbed onto sediments which is a continuing source of contaminant discharge to the river. The Remediation Task of the Science and Technology Project assessed the interaction of groundwater and river water at the hyporheic zone. Limited data have been obtained at this interface of contaminant concentrations, geology, groundwater chemistry, affects of river stage and other variables that may affect strontium-90 release. Efforts were also undertaken to determine the extent, both laterally and horizontally, of the strontium-90 plume along the shoreline and to potentially find an alternative constituent to monitor strontium-90 that would be more cost effective and could possibly be done under real time conditions. A baseline of strontium-90 concentrations along the shoreline was developed to help assess remediation technologies.

  2. Dynamics of an oligotrophic bacterial aquifer community during contact with a groundwater plume contaminated with benzene, toluene, ethylbenzene, and xylenes: an in situ mesocosm study.

    PubMed

    Hendrickx, Barbara; Dejonghe, Winnie; Boënne, Wesley; Brennerova, Maria; Cernik, Miroslav; Lederer, Tomas; Bucheli-Witschel, Margarete; Bastiaens, Leen; Verstraete, Willy; Top, Eva M; Diels, Ludo; Springael, Dirk

    2005-07-01

    An in situ mesocosm system was designed to monitor the in situ dynamics of the microbial community in polluted aquifers. The mesocosm system consists of a permeable membrane pocket filled with aquifer material and placed within a polypropylene holder, which is inserted below groundwater level in a monitoring well. After a specific time period, the microcosm is recovered from the well and its bacterial community is analyzed. Using this system, we examined the effect of benzene, toluene, ethylbenzene, and xylene (BTEX) contamination on the response of an aquifer bacterial community by denaturing gradient gel electrophoresis analysis of PCR-amplified 16S rRNA genes and PCR detection of BTEX degradation genes. Mesocosms were filled with nonsterile or sterile aquifer material derived from an uncontaminated area and positioned in a well located in either the uncontaminated area or a nearby contaminated area. In the contaminated area, the bacterial community in the microcosms rapidly evolved into a stable community identical to that in the adjacent aquifer but different from that in the uncontaminated area. At the contaminated location, bacteria with tmoA- and xylM/xylE1-like BTEX catabolic genotypes colonized the aquifer, while at the uncontaminated location only tmoA-like genotypes were detected. The communities in the mesocosms and in the aquifer adjacent to the wells in the contaminated area consisted mainly of Proteobacteria. At the uncontaminated location, Actinobacteria and Proteobacteria were found. Our results indicate that communities with long-term stability in their structures follow the contamination plume and rapidly colonize downstream areas upon contamination. PMID:16000793

  3. Dynamics of an Oligotrophic Bacterial Aquifer Community during Contact with a Groundwater Plume Contaminated with Benzene, Toluene, Ethylbenzene, and Xylenes: an In Situ Mesocosm Study†

    PubMed Central

    Hendrickx, Barbara; Dejonghe, Winnie; Boënne, Wesley; Brennerova, Maria; Cernik, Miroslav; Lederer, Tomas; Bucheli-Witschel, Margarete; Bastiaens, Leen; Verstraete, Willy; Top, Eva M.; Diels, Ludo; Springael, Dirk

    2005-01-01

    An in situ mesocosm system was designed to monitor the in situ dynamics of the microbial community in polluted aquifers. The mesocosm system consists of a permeable membrane pocket filled with aquifer material and placed within a polypropylene holder, which is inserted below groundwater level in a monitoring well. After a specific time period, the microcosm is recovered from the well and its bacterial community is analyzed. Using this system, we examined the effect of benzene, toluene, ethylbenzene, and xylene (BTEX) contamination on the response of an aquifer bacterial community by denaturing gradient gel electrophoresis analysis of PCR-amplified 16S rRNA genes and PCR detection of BTEX degradation genes. Mesocosms were filled with nonsterile or sterile aquifer material derived from an uncontaminated area and positioned in a well located in either the uncontaminated area or a nearby contaminated area. In the contaminated area, the bacterial community in the microcosms rapidly evolved into a stable community identical to that in the adjacent aquifer but different from that in the uncontaminated area. At the contaminated location, bacteria with tmoA- and xylM/xylE1-like BTEX catabolic genotypes colonized the aquifer, while at the uncontaminated location only tmoA-like genotypes were detected. The communities in the mesocosms and in the aquifer adjacent to the wells in the contaminated area consisted mainly of Proteobacteria. At the uncontaminated location, Actinobacteria and Proteobacteria were found. Our results indicate that communities with long-term stability in their structures follow the contamination plume and rapidly colonize downstream areas upon contamination. PMID:16000793

  4. Three-dimensional analysis of future groundwater flow conditions and contaminant plume transport in the Hanford Site unconfined aquifer system: FY 1996 and 1997 status report

    SciTech Connect

    Cole, C.R.; Wurstner, S.K.; Williams, M.D.; Thorne, P.D.; Bergeron, M.P.

    1997-12-01

    A three-dimensional numerical model of groundwater flow and transport, based on the Coupled Fluid Energy, and Solute Transport (CFEST) code, was developed for the Hanford Site to support the Hanford Groundwater Project (HGWP), managed by Pacific Northwest National Laboratory. The model was developed to increase the understanding and better forecast the migration of several contaminant plumes being monitored by the HGWP, and to support the Hanford Site Composite Analysis for low-level waste disposal in the 200-Area Plateau. Recent modeling efforts have focused on continued refinement of an initial version of the three-dimensional model developed in 1995 and its application to simulate future transport of selected contaminant plumes in the aquifer system. This version of the model was updated using a more current version of the CFEST code called CFEST96. Prior to conducting simulations of contaminant transport with the three-dimensional model, a previous steady-state, two-dimensional model of the unconfined aquifer system was recalibrated to 1979 water-table conditions with a statistical inverse method implemented in the CFEST-INV computer code. The results of the recalibration were used to refine the three-dimensional conceptual model and to calibrate it with a conceptualization that preserves the two-dimensional hydraulic properties and knowledge of the aquifer`s three-dimensional properties for the same 1979 water-table conditions. The transient behavior of the three-dimensional flow model was also calibrated by adjusting model storage properties (specific yield) until transient water-table predictions approximated observed water-table elevations between 1979 and 1996.

  5. Draft Genome Sequence of Acinetobacter oleivorans PF1, a Diesel-Degrading and Plant-Growth-Promoting Endophytic Strain Isolated from Poplar Trees Growing on a Diesel-Contaminated Plume

    PubMed Central

    Gkorezis, Panagiotis; Rineau, Francois; Van Hamme, Jonathan; Daghio, Matteo; Thijs, Sofie; Weyens, Nele

    2015-01-01

    We report the 3.7-Mb draft genome of Acinetobacter oleivorans strain PF1, a hydrocarbonoclastic Gram-negative bacterium in the class Gammaproteobacteria, isolated from poplar trees growing on a diesel-contaminated plume at the Ford Motor Company site in Genk, Belgium. Strain PF1 is a potent plant-growth promoter, useful for diesel fuel phytoremediation applications. PMID:25657268

  6. Geochemical Characteristics of the Contaminant Waste Plume in the F-Area of the Savannah River Site: From Kilometer to Micrometer Scales

    NASA Astrophysics Data System (ADS)

    Dong, W.; Wan, J.; Denham, M.; Seaman, J. C.; Rakshit, S.; Tokunaga, T. K.; Spycher, N.; Hubbard, S. S.

    2010-12-01

    The Savannah River Site (SRS) was a major DOE facility for plutonium production during the Cold War. Low-level radioactivity acidic waste solutions were discharged to a series of unlined seepage basins in the F-Area of the SRS from 1955-1989. Although the site has gone through many years of active remediation, the groundwater remains acidic with pH values as low as 3.2, and the concentrations of U and other radionuclides are still up to ten times higher than their maximum contaminant levels (MCLs). In order to understand the current and predict the future contaminant behavior, a comprehensive investigation is being conducted, funded jointly by the DOE’s offices of Biological and Environmental Resources (BER) and Environmental Management (EM). Five boreholes were drilled outside and within the plume along the groundwater flow path. Samples were collected from varied depths of each borehole, sediment pore-waters were extracted by ultracentrifugation, and the solid phase and pore-water were characterized. We identified the sediment mineralogy as being composed predominantly fine quartz sand with 2 to 12% clay. Kaolinite and goethite are the major minerals of the clay-sized fraction, residing primarily as coatings of varied thicknesses on quartz sand grains, providing reactive surfaces for contaminant adsorption. The measured U “field” distribution coefficients (Kd) and U concentrations in the pore waters are strongly pH dependent. These results are consistent with laboratory equilibrium adsorption studies, where U adsorption onto SRS sediments increases sharply from pH 3 to 5, and reaches ≈100% at pH 6-7. The variability in U adsorption capacity in these sediments is mainly caused by differences in goethite/clay content and effective reactive specific surface area. Measured “field” Kd values are smaller than those obtained from laboratory equilibrium adsorption studies with the same contaminated sediments. The equilibrium pH-dependent U adsorption

  7. Investigation of the potential source area, contamination pathway, and probable release history of chlorinated-solvent-contaminated groundwater at the Capital City Plume Site, Montgomery, Alabama, 2008-2010

    USGS Publications Warehouse

    Landmeyer, James E.; Miller, Scott; Campbell, Bruce G.; Vroblesky, Don A.; Gill, Amy C.; Clark, Athena P.

    2011-01-01

    Detection of the organic solvent perchloroethylene (PCE) in a shallow public-supply well in 1991 and exposure of workers in 1993 to solvent vapors during excavation activities to depths near the water table provided evidence that the shallow aquifer beneath the capital city of Montgomery, Alabama, was contaminated. Investigations conducted from 1993 to 1999 by State and Federal agencies confirmed the detection of PCE in the shallow aquifer, as well as the detection of the organic solvent trichloroethylene (TCE) and various inorganic compounds, but the source of the groundwater contamination was not determined. In May 2000 the U.S. Environmental Protection Agency proposed that the site, called the Capital City Plume (CCP) Site, be a candidate for the National Priorities List. Between 2000 and 2007, numerous site-investigation activities also did not determine the source of the groundwater contamination. In 2008, additional assessments were conducted at the CCP Site to investigate the potential source area, contamination pathway, and the probable release history of the chlorinated-solvent-contaminated groundwater. The assessments included the collection of (1) pore water in 2008 from the hyporheic zone of a creek using passive-diffusion bag samplers; (2) tissue samples in 2008 and 2009 from trees growing in areas of downtown Montgomery characterized by groundwater contamination and from trees growing in riparian zones along the Alabama River and Cypress Creek; and (3) groundwater samples in 2009 and 2010. The data collected were used to investigate the potential source area of contaminants detected in groundwater, the pathway of groundwater contamination, and constraints on the probable contaminant-release history. The data collected between 2008 and 2010 indicate that the PCE and TCE contamination of the shallow aquifer beneath the CCP Site most likely resulted from the past use and disposal of industrial wastewater from printing operations containing chlorinated

  8. Groundwater ecosystem resilience to organic contaminations: microbial and geochemical dynamics throughout the 5-year life cycle of a surrogate ethanol blend fuel plume.

    PubMed

    Ma, Jie; Nossa, Carlos W; Alvarez, Pedro J J

    2015-09-01

    The capacity of groundwater ecosystem to recover from contamination by organic chemicals is a vital concern for environmental scientists. A pilot-scale aquifer system was used to investigate the long-term dynamics of contaminants, groundwater geochemistry, and microbial community structure (by 16S rRNA gene pyrosequencing and quantitative real-time PCR) throughout the 5-year life cycle of a surrogate ethanol blend fuel plume (10% ethanol + 50 mg/L benzene + 50 mg/L toluene). Two-year continuous ethanol-blended release significantly changed the groundwater geochemistry (resulted in anaerobic, low pH, and organotrophic conditions) and increased bacterial and archaeal populations by 82- and 314-fold respectively. Various anaerobic heterotrophs (fermenters, acetogens, methanogens, and hydrocarbon degraders) were enriched. Two years after the release was shut off, all contaminants and their degradation byproducts disappeared and groundwater geochemistry completely restored to the pre-release states (aerobic, neutral pH, and oligotrophic). Bacterial and archaeal populations declined by 18- and 45-fold respectively (relative to the time of shut off). Microbial community structure reverted towards the pre-release states and alpha diversity indices rebounded, suggesting the resilience of microbial community to ethanol blend releases. We also found shifts from O2-sensitive methanogens (e.g., Methanobacterium) to methanogens that are not so sensitive to O2 (e.g., Methanosarcina and Methanocella), which is likely to contribute to the persistence of methanogens and methane generation following the source removal. Overall, the rapid disappearance of contaminants and their metabolites, rebound of geochemical footprints, and resilience of microbial community unequivocally document the natural capacity of groundwater ecosystem to attenuate and recover from a large volume of catastrophic spill of ethanol-based biofuel. PMID:25996759

  9. Evaluation of Visible Plumes.

    ERIC Educational Resources Information Center

    Brennan, Thomas

    Developed for presentation at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971, this outline discusses plumes with contaminants that are visible to the naked eye. Information covers: (1) history of air pollution control regulations, (2) need for methods of evaluating…

  10. Assessment of diesel contamination in groundwater using electromagnetic induction geophysical techniques

    SciTech Connect

    Jin, S.; Fallgren, P.; Cooper, J.; Morris, J; . Urynowicz, M.

    2008-07-01

    Determining hydrocarbon plumes in groundwater is typically accomplished through the installation of extensive monitoring wells. Issues of scale and site heterogeneities tend to introduce errors in delineating the extent of contamination and environmental impact. In this study, electromagnetic induction survey was investigated as an alternative technique for mapping petroleum contaminants in the subsurface. The surveys were conducted at a coal mining site near Gillette, Wyoming, using the EM34-XL ground conductivity meter. Data from this survey were validated with known concentrations of diesel compounds detected in groundwater from the study site. Groundwater data correlated well with the electromagnetic survey data, which was used to generate a site model to identify subsurface diesel plumes. To our knowledge, this is one of the first studies to use electromagnetic survey techniques for mapping hydrocarbon contamination in groundwater. Results from this study indicate that this geophysical technique can be an effective tool for assessing subsurface petroleum hydrocarbon sources and plumes at contaminated sites.

  11. Automated Crater Delineation

    NASA Astrophysics Data System (ADS)

    Marques, J. S.; Pina, P.

    2015-05-01

    An algorithm to delineate impact craters based on Edge Maps and Dynamic Programming is presented. The global performance obtained on 1045 craters from Mars (5 m to about 200 km in diameter), achieved 96% of correct contour delineations.

  12. Plume radiation

    NASA Astrophysics Data System (ADS)

    Dirscherl, R.

    1993-06-01

    The electromagnetic radiation originating from the exhaust plume of tactical missile motors is of outstanding importance for military system designers. Both missile- and countermeasure engineer rely on the knowledge of plume radiation properties, be it for guidance/interference control or for passive detection of adversary missiles. To allow access to plume radiation properties, they are characterized with respect to the radiation producing mechanisms like afterburning, its chemical constituents, and reactions as well as particle radiation. A classification of plume spectral emissivity regions is given due to the constraints imposed by available sensor technology and atmospheric propagation windows. Additionally assessment methods are presented that allow a common and general grouping of rocket motor properties into various categories. These methods describe state of the art experimental evaluation techniques as well as calculation codes that are most commonly used by developers of NATO countries. Dominant aspects influencing plume radiation are discussed and a standardized test technique is proposed for the assessment of plume radiation properties that include prediction procedures. These recommendations on terminology and assessment methods should be common to all employers of plume radiation. Special emphasis is put on the omnipresent need for self-protection by the passive detection of plume radiation in the ultraviolet (UV) and infrared (IR) spectral band.

  13. A comparison of contaminant plume statistics from a Gaussian puff and urban CFD model for two large cities

    NASA Astrophysics Data System (ADS)

    Pullen, Julie; Boris, Jay P.; Young, Theodore; Patnaik, Gopal; Iselin, John

    This paper quantitatively assesses the spatial extent of modeled contaminated regions resulting from hypothetical airborne agent releases in major urban areas. We compare statistics from a release at several different sites in Washington DC and Chicago using a Gaussian puff model (SCIPUFF, version 1.3, with urban parameter settings) and a building-resolving computational fluid dynamics (CFD) model (FAST3D-CT). For a neutrally buoyant gas source term with urban meteorology, we compare near-surface dosage values within several kilometers of the release during the first half hour, before the gas is dispersed beyond the critical lethal level. In particular, using "fine-grain" point-wise statistics such as fractional bias, spatial correlations and the percentage of points lying within a factor of two, we find that dosage distributions from the Gaussian puff and CFD model share few features in common. Yet the "coarse-grain" statistic that compares areas contained within a given contour level reveals that the differences between the models are less pronounced. Most significant among these distinctions is the rapid lofting, leading to enhanced vertical mixing, and projection downwind of the contaminant by the interaction of the winds with the urban landscape in the CFD model. This model-to-model discrepancy is partially ameliorated by supplying the puff model with more detailed information about the urban boundary layer that evolves on the CFD grid. While improving the correspondence of the models when using the "coarse-grain" statistic, the additional information does not lead to quite as substantial an overall agreement between the models when the "fine-grain" statistics are compared. The taller, denser and more variable building landscape of Chicago created increased sensitivity to release site and led to greater divergence in FAST3D-CT and SCIPUFF results relative to the flatter, sparser and more uniform urban morphology of Washington DC.

  14. USE OF AROMATIC ACIDS AND PHOSPHOLIPID-ESTER-LINKED FATTY ACIDS FOR DELINEATION OF PROCESSES AFFECTING AN AQUIFER CONTAMINATED WITH JP-4 FUEL

    EPA Science Inventory

    A glacio-fluvial aquifer located at Wurtsmith Air Force Base, Michigan, has been contaminated with JP-4 fuel hydrocarbons released by the crash of a tanker aircraft in October of 1988. A comprehensive analysis of the inorganic and organic geochemical constituents and geomicrobio...

  15. Delineating contamination of basaltic magma by mafic crust VIA U/Th disequilibrium determined by TIMS, Pisgah Craters, Mojave Desert, California

    SciTech Connect

    Ramos, F.C.; Reid, M.R. . Dept. of Earth and Space Sciences)

    1993-04-01

    Compositional changes in basaltic lavas at Pisgah Craters, CA, are hypothesized to reflect contamination by variable amounts of mafic crust (Glazner et al, 1991). Data determined by Glazner and coworker indicate that the lavas range in isotopic composition from [sup 143]Nd/[sup 144]Nd = 0.51293--0.51276 and [sup 87]Sr/[sup 86]Sr = 0.7038--0.7050, and have decreasing concentrations of incompatible elements with decreasing MgO. The lavas are postulated to range from nearly pure primitive mantle-derived magmas (>8 wt % MgO) early in the eruptive history to nearly pure melts of mafic crust (<4.5 wt % MgO) late in the eruptive history. Preliminary U-series isotopic results obtained by thermal ionization mass spectrometry suggest that the crustal contaminant contains minor concentrations of Th and U. Th and U concentrations in the lavas correlate positively with MgO contents, with ([sup 238]U)/([sup 232]Th) increasing by almost 30% over a variation from 8 to 4.5 wt % MgO. In contrast, [sup 232]Th/[sup 230]Th varies little with MgO concentration and averages 1.8 [times] 10[sup 5] (([sup 230]Th)/([sup 232]Th) [approximately]1.03; 5 samples). The [sup 232]Th/[sup 230]Th ratios of the Pisgah lavas are those expected for mantle-derived magmas based on their Sr and Nd isotopic compositions. The lack of Th isotopic variation coupled with decreasing Th concentrations suggests that the contaminant contained very little Th, consistent with a mafic and/or deep crustal source. U/Th disequilibrium in these lavas indicates that contamination and eruption occurred within the past 50,000 years from the present.

  16. Interpolating and Extrapolating Contaminant Concentrations from Monitor Wells to Model Grids for Fate-and-Transport Calculations

    SciTech Connect

    Ward, D. B.; Clement, P.; Bostick, K.

    2002-02-26

    Geostatistical interpolation of groundwater characterization data to visualize contaminant distributions in three dimensions is often hindered by the sparse distribution of samples relative to the size of the plume and scale of heterogeneities. Typically, placement of expensive monitoring wells is guided by the conceptualized plume rather than geostatistical considerations, focusing on contaminated areas rather than thoroughly gridding the plume boundary. The resulting data sets require careful analysis in order to produce plausible plume shells. A purely geostatistical approach is usually impractical; kriging parameters based on the observed data structure can extrapolate contamination far beyond the demonstrated extent of the plume. When more appropriate kriging parameters are selected, holes often occur in the interpolated distribution because realistic kriging ranges may not bridge large gaps between data points. Such artifacts obscure the probable location of the plume boundary and distort the contaminant distribution, obstructing quantitative modeling of remedial strategies. Two methods of constraining kriging can successfully eliminate these geostatistical artifacts. Laterally, the plume boundary may be controlled using a manually constructed mask that delineates the plan-view extent of the plume. After kriging, the mask is used to set all grid cells outside of the plume to a concentration of zero. Use of non-zero control points is a more refined but laborious approach that also bridges data gaps within the body of a plume and permits use of tighter kriging parameters. These can be obtained by manual linear interpolation between measured samples, or derived from historical data migrated along flow paths while accounting for all attenuative processes. Masking and use of non-zero control points result in a plume shell that reflects the intuition and professional judgment of the hydrologist, and can be interpolated automatically to any desired grid, providing

  17. Delineation of a wellhead protection zone and determination of flowpaths from potential groundwater contaminant source areas at Camp Ripley, Little Falls, Minnesota.

    SciTech Connect

    Quinn, J. J.; Environmental Science Division

    2006-12-22

    Groundwater at Camp Ripley, Minnesota, is recharged both on post and off site and discharged to rivers, wetlands, and pumping wells. The subsurface geologic materials have a wide range of permeabilities and are arranged in a complex fashion as a result of the region's multiple glacial advances. Correlation of individual glacial geologic units is difficult, even between nearby boreholes, because of the heterogeneities in the subsurface. This report documents the creation of a numerical model of groundwater flow for Camp Ripley and hydrologically related areas to the west and southwest. The model relies on a hydrogeological conceptual model built on the findings of a University of Minnesota-Duluth drilling and sampling program conducted in 2001. Because of the site's stratigraphic complexity, a geostatistical approach was taken to handle the uncertainty of the subsurface correlation. The U.S. Geological Survey's MODFLOW code was used to create the steady-state model, which includes input data from a variety of sources and is calibrated to water levels in monitoring wells across much of the site. This model was used for several applications. Wellhead protection zones were delineated for on-site production wells H, L, and N. The zones were determined on the basis of a probabilistic assessment of the groundwater captured by these wells; the assessment, in turn, had been based on multiple realizations of the study area's stratigraphy and groundwater flowfield. An additional application of the model was for estimating flowpaths and times of travel for groundwater at Camp Ripley's range areas and waste management facilities.

  18. Effect of bipropellant plume exhaust effluents on spaceborne optical instruments

    NASA Astrophysics Data System (ADS)

    Maag, C. R.; Jeffery, J. A.; Millard, J. M.

    1980-01-01

    Analytical tools together with a good data base are necessary to predict the transport of plume contaminants and their effects on spacecraft surfaces. The present paper describes an assessment of bipropellant thrusters, the production and transport of plume contaminants from these thrusters, and the use of the JPL contamination analysis program to assess the effects of plume contamination on the Galileo spacecraft. It is shown that, in the case of the Galileo mission, contamination from the liquid engines has been effectively reduced to nothing by the use of predictive tools. Plume shields together with precise scan platform stowage have been designed to protect the optical instruments.

  19. Y-12 Groundwater Protection Program Extent Of The Primary Groundwater Contaminants At The Y-12 National Security Complex

    SciTech Connect

    2013-12-01

    This report presents data summary tables and maps used to define and illustrate the approximate lateral extent of groundwater contamination at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12) in Oak Ridge, Tennessee. The data tables and maps address the primary (i.e., most widespread and mobile) organic, inorganic, and radiological contaminants in the groundwater. The sampling locations, calculated contaminant concentrations, plume boundary values, and paired map format used to define, quantify, delineate, and illustrate the approximate extent of the primary organic, inorganic, and radiological contaminants in groundwater at Y-12 are described.

  20. Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE

    SciTech Connect

    Bloom, Aleisa C

    2015-01-01

    ). It originated from at least four separate source areas that comingled in the subsurface to form the large plume. The major contaminants of concern (COCs) are tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1-TCA), which were historically used for degreasing operations in the maintenance of aircraft and support vehicles. Relatively small areas of elevated PCE, TCE, and 1,1,1-TCA were delineated in the shallow portion of the water table aquifer by direct-push groundwater sampling. Focused direct-push AAB treatment occurred in March 2006 at these source areas (Figure 1). Downgradient of the these areas and deeper in the aquifer, AAB treatment was implemented using rows of extraction/injection wells oriented perpendicular to groundwater flow to create multiple reductive zones across the plume cores, defined as areas where more than 1,000 micrograms per liter (ug/L) total solvent concentrations were present. Initial indications of successful degradation were observed within 6 months of starting injections. FIGURE 1. Dover AFB Area 6 plume. This paper describes the AAB implementation and progress of remediation after 8 years of treatment and periodic groundwater monitoring. SITE LITHOLOGY Contamination at the site is limited to the surficial aquifer, which consists of 35 to 50 feet (ft) (11 to 15 meters [m]) of unconsolidated Pleistocene deposits of the Columbia Formation. The Columbia Formation consists of fine to coarse sand with silt and clay lenses and less common gravel lenses. Silts and silty sands are generally encountered to a depth of 10 to 12 ft (3.05 to 3.65 m) below ground surface (bgs) and grade to medium- and coarse-grained sands to a depth of 35 to 50 ft (11 to 15 m) bgs. There is a clay and silt unit (part of the Calvert Formation) below the surficial aquifer that acts as an aquitard to the downward migration of contaminants. The depth to the water table varies across the site but usually ranges from 8 to 15 ft (2.4 to 4.5 m

  1. Phytoscreening for chlorinated solvents using rapid in vitro SPME sampling: Application to urban plume in Verl, Germany

    USGS Publications Warehouse

    Limmer, M.A.; Balouet, J.-C.; Karg, F.; Vroblesky, D.A.; Burken, J.G.

    2011-01-01

    Rapid detection and delineation of contaminants in urban settings is critically important in protecting human health. Cores from trees growing above a plume of contaminated groundwater in Verl, Germany, were collected in 1 day, with subsequent analysis and plume mapping completed over several days. Solid-phase microextraction (SPME) analysis was applied to detect tetrachloroethene (PCE) and trichloroethene (TCE) to below nanogram/liter levels in the transpiration stream of the trees. The tree core concentrations showed a clear areal correlation to the distribution of PCE and TCE in the groundwater. Concentrations in tree cores were lower than the underlying groundwater, as anticipated; however, the tree core water retained the PCE:TCE signature of the underlying groundwater in the urban, populated area. The PCE:TCE ratio can indicate areas of differing degradation activity. Therefore, the phytoscreening analysis was capable not only of mapping the spatial distribution of groundwater contamination but also of delineating zones of potentially differing contaminant sources and degradation. The simplicity of tree coring and the ability to collect a large number of samples in a day with minimal disruption or property damage in the urban setting demonstrates that phytoscreening can be a powerful tool for gaining reconnaissance-level information on groundwater contaminated by chlorinated solvents. The use of SPME decreases the detection level considerably and increases the sensitivity of phytoscreening as an assessment, monitoring, and phytoforensic tool. With rapid, inexpensive, and noninvasive methods of detecting and delineating contaminants underlying homes, as in this case, human health can be better protected through screening of broader areas and with far faster response times. ?? 2011 American Chemical Society.

  2. Phytoscreening for chlorinated solvents using rapid in vitro SPME sampling: application to urban plume in Verl, Germany.

    PubMed

    Limmer, Matt A; Balouet, Jean-Christophe; Karg, Frank; Vroblesky, Don A; Burken, Joel G

    2011-10-01

    Rapid detection and delineation of contaminants in urban settings is critically important in protecting human health. Cores from trees growing above a plume of contaminated groundwater in Verl, Germany, were collected in 1 day, with subsequent analysis and plume mapping completed over several days. Solid-phase microextraction (SPME) analysis was applied to detect tetrachloroethene (PCE) and trichloroethene (TCE) to below nanogram/liter levels in the transpiration stream of the trees. The tree core concentrations showed a clear areal correlation to the distribution of PCE and TCE in the groundwater. Concentrations in tree cores were lower than the underlying groundwater, as anticipated; however, the tree core water retained the PCE:TCE signature of the underlying groundwater in the urban, populated area. The PCE:TCE ratio can indicate areas of differing degradation activity. Therefore, the phytoscreening analysis was capable not only of mapping the spatial distribution of groundwater contamination but also of delineating zones of potentially differing contaminant sources and degradation. The simplicity of tree coring and the ability to collect a large number of samples in a day with minimal disruption or property damage in the urban setting demonstrates that phytoscreening can be a powerful tool for gaining reconnaissance-level information on groundwater contaminated by chlorinated solvents. The use of SPME decreases the detection level considerably and increases the sensitivity of phytoscreening as an assessment, monitoring, and phytoforensic tool. With rapid, inexpensive, and noninvasive methods of detecting and delineating contaminants underlying homes, as in this case, human health can be better protected through screening of broader areas and with far faster response times. PMID:21848303

  3. Dynamics of the Chesapeake Bay outflow plume: Realistic plume simulation and its seasonal and interannual variability

    NASA Astrophysics Data System (ADS)

    Jiang, Long; Xia, Meng

    2016-02-01

    The three-dimensional unstructured-grid Finite Volume Coastal Ocean Model (FVCOM) was implemented for Chesapeake Bay and its adjacent coastal ocean to delineate the realistic Chesapeake Bay outflow plume (CBOP) as well as its seasonal and interannual variability. Applying the appropriate horizontal and vertical resolution, the model exhibited relatively high skill in matching the observational water level, temperature, and salinity from 2003 to 2012. The simulated surface plume structure was verified by comparing output to the HF radar current measurements, earlier field observations, and the MODIS and AVHRR satellite imagery. According to the orientation, shape, and size of the CBOP from both model snapshots and satellite images, five types of real-time plume behavior were detected, which implied strong regulation by wind and river discharge. In addition to the episodic plume modulation, horizontal and vertical structure of the CBOP exhibited variations on seasonal and interannual temporal scales. Seasonally, river discharge with a 1 month lag was primarily responsible for the surface plume area variation, while the plume thickness was mainly correlated to wind magnitude. On the interannual scale, river discharge was the predominant source of variability in both surface plume area and depth; however, the southerly winds also influenced the offshore plume depth. In addition, large-scale climate variability, such as the North Atlantic Oscillation, could potentially affect the plume signature in the long term by altering wind and upwelling dynamics, underlining the need to understand the impacts of climate change on buoyant plumes, such as the CBOP.

  4. Spatially resolved U(VI) partitioning and speciation: Implications for plume scale behavior of contaminant U in the Hanford vadose zone

    SciTech Connect

    Wan, Jiamin; Kim, Yongman; Tokunaga, Tetsu K.; Wang, Zheming; Dixit, Suvasis; Steefel, Carl; Saiz, Eduardo; Kunz, Martin; Tamura, Nobumichi

    2009-02-01

    A saline-alkaline brine containing high concentrations of U(VI) was accidentally spilled at the Hanford Site in 1951, introducing 10 tons of U into sediments under storage tank BX-102. U concentrations in the deep vadose zone and groundwater plumes increase with time, yet how the U has been migrating is not fully understood. We simulated the spill event in laboratory soil columns, followed by aging, and obtained spatially resolved U partitioning and speciation along simulated plumes. We found after aging, at apparent steady state, that the pore aqueous phase U concentrations remained surprisingly high (up to 0.022 M), in close agreement with the recently reported high U concentrations (up to 0.027 M) in the vadose zone plume (1). The pH values of aged pore liquids varying from 10 to 7, consistent with the measured pH of the field borehole sediments varying from 9.5 to 7.4 (2), from near the plume source to the plume front. The direct measurements of aged pore liquids together with thermodynamic calculations using a Pitzer approach revealed that UO{sub 2}(CO{sub 3}){sub 3} {sup 4-} is the dominant aqueous U species within the plume body (pH 8-10), while Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} and CaUO{sub 2}(CO{sub 3}){sub 3}{sup 2-} are also significant in the plume front vicinity (pH 7-8), consistent with that measured from field borehole porewaters (3). U solid phase speciation varies at different locations along the plume flow path and even within single sediment grains, because of location dependent pore and micropore solution chemistry. Our results suggest that high geochemical stability of UO{sub 2}(CO{sub 3}){sub 3}{sup 4-} in the original carbonate and sodium rich waste solution permits its continues migration and the field observed increases of U concentrations in the vadose zone and groundwater.

  5. Challenge in Flow Path Delineation and Modification: SECUREarth Initiative

    NASA Astrophysics Data System (ADS)

    Bodvarsson, G. S.; Majer, E. L.; Wang, J. S.; Colwell, F.; Redden, G.

    2005-12-01

    After decades of studies, our knowledge about subsurface flow paths has large uncertainty and our capability to enhance or reduce formation permeability is inefficient and rudimentary. This is the case for fossil energy production, in environment remediation, in greenhouse gas sequestration, in nuclear waste disposal, in geothermal heat extraction, and in groundwater management. Fluid imaging, in addition to rock structure imaging, is needed to enhance petroleum extraction, to isolate contaminant plumes, and to prevent leakage from storage reservoirs. Flow focusing from surface to depth must be quantified to determine the flow path magnitude and spacing in order to determine the degrees of dissolution and transport of emplaced wastes. These diverse problems have common goals: either to isolate or to enhance subsurface fluid movement. It is crucial to identify the common features from different problems and refocus our efforts to delineate and then to manipulate flow paths. Geochemical engineering and geomicrobiological engineering need to combine laboratory studies, field experiments, and modeling approaches to verify and validate our understanding and to design solutions. An initiative SECUREarth is being developed to rally the scientists and engineers from national laboratories, universities, and industry to address key critical bottlenecks that prevent significant progress in solving common subsurface issues. SECUREarth is aimed to develop cross-cutting, multi-disciplinary approaches for solving urgent energy and environment problems in the earth, in order to achieve quantum leaps and breakthroughs in earth science and technology.

  6. Proactive screening approach for detecting groundwater contaminants along urban streams at the reach-scale.

    PubMed

    Roy, James W; Bickerton, Greg

    2010-08-15

    Here we outline and demonstrate a screening approach for the detection of groundwater contaminants along urban streams within unconsolidated beds. It involves the rapid acquisition of groundwater samples along urban stream reaches at a spacing of about 10 m and from depths of about 25-75 cm below the streambed, with analyses for a suite of potential contaminants. This screening approach may serve two functions: a) providing information for assessing and mitigating the toxicity and eutrophication risks to aquatic ecosystems posed by groundwater contaminants and b) detecting and identifying groundwater contamination in urban settings more rapidly and inexpensively compared to land-based well installations. The screening approach was tested at three urban streams, each affected by a known chlorinated-solvent plume. All three known groundwater plumes were detected and roughly delineated. Multiple, previously unknown, areas or types of groundwater contamination were also identified at each stream. The newly identified contaminants and plumes included petroleum hydrocarbons (BTEX, naphthalene, MTBE), 1,4-dioxane, nitrate and phosphate, road salt, and various metals (including arsenic, cadmium, chromium, copper, lead) at elevated concentrations compared to background values and relevant Canadian water quality guidelines. These findings suggest that this screening approach may be a useful tool for both ecologists performing ecological assessments and stream restorations and for hydrogeologists undertaking groundwater protection activities. Given the numerous contaminants detected, it may be appropriate to apply this technique proactively to better determine the pervasiveness of urban groundwater contaminants, especially along urban streams. PMID:20617839

  7. Optimized Field Sampling and Monitoring of Airborne Hazardous Transport Plumes; A Geostatistical Simulation Approach

    SciTech Connect

    Chen, DI-WEN

    2001-11-21

    Airborne hazardous plumes inadvertently released during nuclear/chemical/biological incidents are mostly of unknown composition and concentration until measurements are taken of post-accident ground concentrations from plume-ground deposition of constituents. Unfortunately, measurements often are days post-incident and rely on hazardous manned air-vehicle measurements. Before this happens, computational plume migration models are the only source of information on the plume characteristics, constituents, concentrations, directions of travel, ground deposition, etc. A mobile ''lighter than air'' (LTA) system is being developed at Oak Ridge National Laboratory that will be part of the first response in emergency conditions. These interactive and remote unmanned air vehicles will carry light-weight detectors and weather instrumentation to measure the conditions during and after plume release. This requires a cooperative computationally organized, GPS-controlled set of LTA's that self-coordinate around the objectives in an emergency situation in restricted time frames. A critical step before an optimum and cost-effective field sampling and monitoring program proceeds is the collection of data that provides statistically significant information, collected in a reliable and expeditious manner. Efficient aerial arrangements of the detectors taking the data (for active airborne release conditions) are necessary for plume identification, computational 3-dimensional reconstruction, and source distribution functions. This report describes the application of stochastic or geostatistical simulations to delineate the plume for guiding subsequent sampling and monitoring designs. A case study is presented of building digital plume images, based on existing ''hard'' experimental data and ''soft'' preliminary transport modeling results of Prairie Grass Trials Site. Markov Bayes Simulation, a coupled Bayesian/geostatistical methodology, quantitatively combines soft information

  8. Delineation of ecosystem regions

    NASA Astrophysics Data System (ADS)

    Bailey, Robert G.

    1983-07-01

    As a means of developing reliable estimates of ecosystem productivity, ecosystem classification needs to be placed within a geographical framework of regions or zones. This paper explains the basis for the regions delineated on the 1976 map Ecoregions of the United States. Four ecological levels are discussed—domain, division, province, and section—based on climatic and vegetational criteria. Statistical tests are needed to verify and refine map units.

  9. Dust Plumes off Libya

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Two-toned dust plumes blew northward off the coast of Libya on October 26, 2007, as the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite took this picture. While plumes in the west are beige, reminiscent of the Sahara's sands, the plumes in the east are distinctly darker. The differences in color can be traced to the plumes's varied origins.

  10. Application of dig-face monitoring during excavation of a radioactive plume

    SciTech Connect

    Josten, N.E.; Gehrke, R.; Stanley, R.; MacMahan, K.

    1996-11-01

    Dig-face characterization is a concept for improving the safety and efficiency of hazardous waste retrieval. A dig-face characterization system consists of onsite hardware for collecting detailed information on the changing chemical, radiological, and physical conditions in the subsurface during the entire course of a hazardous site excavation. The dig-face characterization concept originated at the Idaho National Engineering Laboratory and has been under development there since 1992. During August 1995, a prototype dig-face system was taken to Mound Laboratory, Ohio, for a first attempt at monitoring a hazardous excavation. Mound Area 7 was the site of historical disposals of {sup 232}Th, {sup 227}Ac, and assorted debris. The dig-face characterization system was used to monitor a 20-ft x 20-ft x 5-ft-deep excavation aimed at removing {sup 227}Ac contaminated soils. Radiological, geophysical, and topographic sensors were scanned across the excavation dig-face at four successive depths as soil was removed in 1-ft to 2-ft lifts. The geophysical and topographic sensors located metallic debris and mapped the dig-face topography in great detail as the excavation advanced. The radiation sensors produced high-fidelity images showing the location of radioactive contaminants and clearly identified and delineated separate {sup 232}Th and {sup 227}Ac plumes. By combining the radiation data from all four levels, a three-dimensional image of the contamination plumes was developed. The radiation sensor data indicated that only a small portion of the excavated soil volume was contaminated. The spatial information produced by the dig-face system was used to direct the excavation activities into the area containing the {sup 227}Ac and to evaluate options for handling the separate {sup 232}Th plume.

  11. Sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts

    USGS Publications Warehouse

    LeBlanc, D.R.

    1982-01-01

    Secondarily treated domestic sewage has been disposed of to a sand and gravel aquifer by infiltration through sand beds at Otis Air Force Base, Massachusetts, since 1936. The disposal has formed a plume of contaminated ground water that is more than 11 ,000 feet long, is 2,500 to 3,500 feet wide and 75 feet thick, and is overlain by 20 to 50 feet of uncontaminated ground water derived from precipitation. The distributions of specific conductance, temperature, boron chloride, sodium, phosphorus, nitrogen, ammonia, nitrate, dissolved oxygen, and detergents are used to delineate the plume. The center of the plume contains up to 2.6 milligrams per liter detergents as MBAS (methylene blue active substances), 0.4 milligram per liter boron, 20 milligrams per liter ammonia-nitrogen, and specific conductance as high as 405 micromhos per centimeter. Corresponding levels in uncontaminated ground water are less than 0.1 milligram per liter detergents, less than 0.1 ammonia-nitrogen, less than 0.05 milligram per liter boron, and less than 80 micromhos per centimeter specific conductance. Chloride, sodium, and boron concentrations seem to be affected only by hydrodynamic dispersion. Phosphorus movement is greatly retarded by sorption. Detergent concentrations exceed 0.5 milligram per liter from 3 ,000 to 10,000 feet from the sand beds and reflect the use of nonbiodegradable detergents from 1946 through 1964. The center of the plume as far as 5,000 feet from the sand beds contains nitrogen as ammonia, no nitrate, and no dissolved oxygen. Ammonia is oxidized to nitrate gradually with distance from the center of the plume. (USGS)

  12. INDEPENDENT TECHNICAL REVIEW OF THE BUILDING 100 PLUME, FORMER DOE PINELLAS SITE (YOUNG - RAINEY STAR CENTER), LARGO, FLORIDA

    SciTech Connect

    Eddy-Dilek, C.; Rossabi, J.; Amidon, M.; Riha, B.; Kaback, D.

    2010-07-30

    Contaminated groundwater associated with Building 100 at the Young-Rainey Science, Technology, and Research Center, formerly the DOE Pinellas plant, is the primary remedial challenge that remains to be addressed at the site. Currently, Building 100 is an active industrial facility that is now owned and operated by the Pinellas county government. Groundwater samples collected from monitoring wells recently installed near the southern boundary of the site suggest that contaminated groundwater has migrated off the plant site. In response to the challenges presented by the Building 100 plume, the Office of Legacy Management (LM) requested assistance from the DOE Office of Groundwater and Soil Remediation (EM-32) to provide a review team to make technical recommendations so that they can efficiently and effectively address characterization and remediation of the plume. The review team was unanimous in the conclusion that a dynamic strategy that combines a phased implementation of direct push samplers, sensors, and tools can be used to better delineate the extent of contamination, control plume migration, and rapidly remediate the contaminated groundwater at the site. The initial efforts of the team focused on reviewing the site history and data, organizing the information into a conceptual model, identifying appropriate technologies, and recommending an integrated strategy. The current groundwater data from the site indicate a two-lobed plume extending to the east and south. To the east vinyl chloride is the primary contaminant of concern, to the south, vinyl chloride and cis1, 2-DCE are the primary contaminants. The limited data that are available suggest that reductive dechlorination of the TCE is already occurring but is not sufficient to prevent offsite migration of low concentrations of TCE daughter products. The team recommends that DOE pursue a strategy that builds on the natural cleansing capacity of the subsurface with reductive methods including biostimulation

  13. Assessment of ground-water contamination at Wurtsmith Air Force Base, Michigan, 1982-85

    USGS Publications Warehouse

    Cummings, T.R.; Twenter, F.R.

    1986-01-01

    Study of ground-water contamination at Wurtsmith Air Force Base, Michigan, defined the movement and distribution of volatile organic compounds in the glacial sand and gravel aquifer at known sites of contamination, and has defined new plumes at two other sites. The Arrow Street purge system, installed in 1982 to remove contaminants from the Building 43 plume, has lowered concentrations of trichloroethylene (TCE) in groundwater in the central part of the most contaminated area from a range of 1,000 to 2,000 microg/L to about 200 microg/L. TCE is not escaping off-Base from this area. In the southern part of the Base a plume containing principally TCE and dichloroethylene (DCE) has been delineated along Mission Drive. Maximum concentrations observed were 3,290 microg/L of TCE and 1,480 microg/L of DCE. Hydrologically suitable sites for purge wells were identified in the southern part of the plume using a new ground-water flow model of the Base. A benzene plume near the bulk-fuel storage area has shifted to a more northerly direction under influence of the Arrow Street purge system. Sites initially identified for purging the benzene plume have been repositioned because of the change in contaminant movement. JP-4 fuel was found to be accumulating in wells near the bulk-fuel storage area, largely in response to seasonal fluctuations in the water-table. It is thought to originate from a spill that occurred several years ago. In general, concentrations found in water do not differ greatly from those observed in 1981. Since 1981, concentrations of TCE have decreased significantly in the Alert Apron plume. Near the origin of the plume, the concentration of TCE has decreased from 1,000 microg/L in 1980 to 50 microg/L in 1984. Water from Van Etten Lake near the termination of the plume had only a trace of TCE at one site. Benzene detected in water from well AF2 seems to originate near the former site of buried fuel tanks west of the operational apron. During periods of normal

  14. Geochemical and microbiological methods for evaluating anaerobic processes in an aquifer contaminated by landfill leachate

    USGS Publications Warehouse

    Cozzarelli, I.M.; Suflita, J.M.; Ulrich, G.A.; Harris, S.H.; Scholl, M.A.; Schlottmann, J.L.; Christenson, S.

    2000-01-01

    A combined geochemical and microbiological approach was needed to delineate the biogeochemical processes occurring in an aquifer contaminated by landfill leachate in Norman, OK, where the important microbially mediated reactions in an anoxic plume were iron reduction, sulfate reduction, and methanogenesis. The highest rates of sulfate reduction (13.2 ??M/day) were detected near the water table where sulfate levels were maximal (up to 4.6 mM). The enrichment of 34S in the sulfate pools (??34S of SO42- was 67-69%0), and dissolved hydrogen measurements provided additional support for the importance of sulfate reduction near the water table. Methane was detected in the center of the plume where sulfate was depleted. Microbial incubations demonstrated concomitant sulfate reduction and methanogenesis in the anoxic portion of the plume. Although high concentrations of soluble reduced iron were detected throughout the aquifer and H2 levels were indicative of iron reduction under steady-state conditions, microbiological experiments showed that iron reduction was active only at the edges of the sulfate-depleted portion of the plume. This study demonstrates the benefits of using a combined geochemical and microbiological approach to elucidate the spatial distribution of biogeochemical processes in contaminated aquifers.A combined geochemical and microbiological approach was needed to delineate the biogeochemical processes occurring in an aquifer contaminated by landfill leachate in Norman, OK, where the important microbially mediated reactions in an anoxic plume were iron reduction, sulfate reduction, and methanogenesis. The highest rates of sulfate reduction (13.2 ??M/day) were detected near the water table where sulfate levels were maximal (up to 4.6 mM). The enrichment of 34S in the sulfate pools (??34S of SO42- was 67-69 per mil), and dissolved hydrogen measurements provided additional support for the importance of sulfate reduction near the water table. Methane was

  15. Geophysical Signitures From Hydrocarbon Contaminated Aquifers

    NASA Astrophysics Data System (ADS)

    Abbas, M.; Jardani, A.

    2015-12-01

    The task of delineating the contamination plumes as well as studying their impact on the soil and groundwater biogeochemical properties is needed to support the remediation efforts and plans. Geophysical methods including electrical resistivity tomography (ERT), induced polarization (IP), ground penetrating radar (GPR), and self-potential (SP) have been previously used to characterize contaminant plumes and investigate their impact on soil and groundwater properties (Atekwana et al., 2002, 2004; Benson et al., 1997; Campbell et al., 1996; Cassidy et al., 2001; Revil et al., 2003; Werkema et al., 2000). Our objective was to: estimate the hydrocarbon contamination extent in a contaminated site in northern France, and to adverse the effects of the oil spill on the groundwater properties. We aim to find a good combination of non-intrusive and low cost methods which we can use to follow the bio-remediation process, which is planned to proceed next year. We used four geophysical methods including electrical resistivity tomography, IP, GPR, and SP. The geophysical data was compared to geochemical ones obtained from 30 boreholes installed in the site during the geophysical surveys. Our results have shown: low electrical resistivity values; high chargeability values; negative SP anomalies; and attenuated GPR reflections coincident with groundwater contamination. Laboratory and field geochemical measurements have demonstrated increased groundwater electrical conductivity and increased microbial activity associated with hydrocarbon contamination of groundwater. Our study results support the conductive model suggested by studies such as Sauck (2000) and Atekwana et al., (2004), who suggest that biological alterations of hydrocarbon contamination can substantially modify the chemical and physical properties of the subsurface, producing a dramatic shift in the geo-electrical signature from resistive to conductive. The next stage of the research will include time lapse borehole

  16. Model based evaluation of a contaminant plume development under aerobic and anaerobic conditions in 2D bench-scale tank experiments.

    PubMed

    Ballarini, E; Beyer, C; Bauer, R D; Griebler, C; Bauer, S

    2014-06-01

    The influence of transverse mixing on competitive aerobic and anaerobic biodegradation of a hydrocarbon plume was investigated using a two-dimensional, bench-scale flow-through laboratory tank experiment. In the first part of the experiment aerobic degradation of increasing toluene concentrations was carried out by the aerobic strain Pseudomonas putida F1. Successively, ethylbenzene (injected as a mixture of unlabeled and fully deuterium-labeled isotopologues) substituted toluene; nitrate was added as additional electron acceptor and the anaerobic denitrifying strain Aromatoleum aromaticum EbN1 was inoculated to study competitive degradation under aerobic /anaerobic conditions. The spatial distribution of anaerobic degradation was resolved by measurements of compound-specific stable isotope fractionation induced by the anaerobic strain as well as compound concentrations. A fully transient numerical reactive transport model was employed and calibrated using measurements of electron donors, acceptors and isotope fractionation. The aerobic phases of the experiment were successfully reproduced using a double Monod kinetic growth model and assuming an initial homogeneous distribution of P. putida F1. Investigation of the competitive degradation phase shows that the observed isotopic pattern cannot be explained by transverse mixing driven biodegradation only, but also depends on the inoculation process of the anaerobic strain. Transient concentrations of electron acceptors and donors are well reproduced by the model, showing its ability to simulate transient competitive biodegradation. PMID:24122285

  17. Turbulent Plumes in Nature

    NASA Astrophysics Data System (ADS)

    Woods, Andrew W.

    2010-01-01

    This review describes a range of natural processes leading to the formation of turbulent buoyant plumes, largely relating to volcanic processes, in which there are localized, intense releases of energy. Phenomena include volcanic eruption columns, bubble plumes in lakes, hydrothermal plumes, and plumes beneath the ice in polar oceans. We assess how the dynamics is affected by heat transfer, particle fallout and recycling, and Earth's rotation, as well as explore some of the mixing of the ambient fluid produced by plumes in a confined geometry.

  18. Dust Plume off Mauritania

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A thick plume of dust blew off the coast of Mauritania in western Africa on October 2, 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite observed the dust plume as it headed toward the southwest over the Atlantic Ocean. In this image, the dust varies in color from nearly white to medium tan. The dust plume is easier to see over the dark background of the ocean, but the plume stretches across the land surface to the east, as well. The dust plume's structure is clearest along the coastline, where relatively clear air pockets separate distinct puffs of dust. West of that, individual pillows of dust push together to form a more homogeneous plume. Near its southwest tip, the plume takes on yet another shape, with stripes of pale dust fanning out toward the northwest. Occasional tiny white clouds dot the sky overhead, but skies are otherwise clear.

  19. Modeling Europa's dust plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B. S.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Jupiter's moon Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we simulate possible Europa plume configurations, analyze particle number density and surface deposition results, and estimate the expected flux of ice grains on a spacecraft. Due to Europa's high escape speed, observing an active plume will require low-altitude flybys, preferably at altitudes of 5-100 km. At higher altitudes a plume may escape detection. Our simulations provide an extensive library documenting the possible structure of Europa dust plumes, which can be quickly refined as more data on Europa dust plumes are collected.

  20. Plume development in Long Island Sound observed by remote sensing (ERTS-1)

    NASA Technical Reports Server (NTRS)

    Ruggles, F. H., Jr.

    1973-01-01

    As the Connecticut River flows into Long Island Sound, large plumes are developed during the mixing of ocean and estuarine waters. Plumes were delineated for July 28, October 8, October 27, and December 2, 1972, by analyzing ERTS-1 imagery with the SRI electronic satellite image analysis console (ESIAC). Insertion of MSS band 5 into the ESIAC produced the best result in this analysis. The four plumes that have been delineated provide the first input to a time-lapse analysis of circulation patterns at the eastern end of Long Island Sound.

  1. SH-Wave Imaging of Potential Near-Surface Geologic Controls on Contaminant Plume Migration: Fluorspar Area Fault Complex, Western Kentucky USA

    NASA Astrophysics Data System (ADS)

    Almayahi, A.; Woolery, E.; Hampson, S.

    2011-12-01

    Subbottom lake stratification is of interest to hydrology and core site selection, and in delta formation, sediment focusing and periglacial dynamics. Mirror Lake, New Hampshire, within the Hubbard Brook research area, has long been studied, but its subbottom stratification has only been estimated from coring that revealed up to 13 m of gyttja above about 1 m of Late Wisconsin glacial silt. However, the very low water conductivity of 0.002-0.003 S/m allows exceptional penetration of ground-penetrating radar (GPR) signals. Here we discuss several GPR profiles recorded at pulse center frequencies of 60 and 120 MHz along 300-600 m transects that crossed the entire lake in many directions. With care not to misinterpret multiple reflection horizons, the profiles clearly delineate gyttja, till, bedrock horizons, boulder horizons near shore and deltaic deposition. Hyperbolic backscatter in the well-stratified gyttja may be responses from buried logs because they often occur in nests of close, deepening diffractions and much logging historically occurred. Strong local horizons within the gyttja suggest sediment retransport and focusing, as suggested by Davis and Ford in their1982 interpretation of cores. The generally deeper and underlying till is characterized by sections of dense diffractions. In some profile sections internal till horizons appear draped over the bedrock horizons. In others parallel and deep horizons may be responses to bedrock fractures. Using estimated minimal wave speeds based on maximum possible dielectric permittivities calculated from assumed saturated conditions, and partly verified by diffraction interpretation after statics removal, our 60 MHz profiles show gyttja (permittivity no greater than 53) thicknesses of at least 11 m, till (permittivity no greater than 33) thicknesses of at least 25 m and depths to bedrock (Littleton schist) up to 28 m. This till thickness far exceeds the average 4-5 m on the surrounding slopes of the Hubbard Brook

  2. Paducah Gaseous Diffusion Plant Northwest Plume interceptor system evaluation

    SciTech Connect

    Laase, A.D.; Clausen, J.L.

    1998-07-01

    The Paducah Gaseous Diffusion Plant (PGDP) recently installed an interceptor system consisting of four wells, evenly divided between two well fields, to contain the Northwest Plume. As stated in the Northwest Plume Record of Decision (ROD), groundwater will be pumped at a rate to reduce further contamination and initiate control of the northwest contaminant plume. The objective of this evaluation was to determine the optimum (minimal) well field pumping rates required for plume hotspot containment. Plume hotspot, as defined in the Northwest Plume ROD and throughout this report, is that portion of the plume with trichloroethene (TCE) concentrations greater than 1,000 {micro}g/L. An existing 3-dimensional groundwater model was modified and used to perform capture zone analyses of the north and south interceptor system well fields. Model results suggest that the plume hotspot is not contained at the system design pumping rate of 100 gallons per minute (gal/min) per well field. Rather, the modeling determined that north and south well field pumping rates of 400 and 150 gal/min, respectively, are necessary for plume hotspot containment. The difference between the design and optimal pumping rates required for containment can be attributed to the discovery of a highly transmissive zone in the vicinity of the two well fields.

  3. Modeling Europa's Dust Plumes

    NASA Astrophysics Data System (ADS)

    Southworth, B.; Kempf, S.; Schmidt, J.

    2015-12-01

    The discovery of Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring the properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we adjust the ejection model by Schmidt et al. [2008] to the conditions at Europa. In this way, we estimate properties of a possible, yet unobserved dust component of the Europa plume. For a size-dependent speed distribution of emerging ice particles we use the model from Kempf et al. [2010] for grain dynamics, modified to run simulations of plumes on Europa. Specifically, we model emission from the two plume locations determined from observations by Roth et al. [2014] and also from other locations chosen at the closest approach of low-altitude flybys investigated in the Europa Clipper study. This allows us to estimate expected fluxes of ice grains on the spacecraft. We then explore the parameter space of Europa dust plumes with regard to particle speed distribution parameters, plume location, and spacecraft flyby elevation. Each parameter set results in a 3-dimensional particle density structure through which we simulate flybys, and a map of particle fallback ('snowfall') on the surface of Europa. Due to the moon's high escape speed, a Europa plume will eject few to no particles that can escape its gravity, which has several further consequences: (i) For given ejection velocity a Europa plume will have a smaller scale height, with a higher particle number densities than the plume on Enceladus, (ii) plume particles will not feed the diffuse Galilean dust ring, (iii) the snowfall pattern on the surface will be more localized about the plume location, and will not induce a global m = 2 pattern as seen on Enceladus, and (iv) safely observing an active plume will require low altitude flybys, preferably at 50

  4. Hydrogeological modeling constraints provided by geophysical and geochemical mapping of a chlorinated ethenes plume in northern France

    NASA Astrophysics Data System (ADS)

    Razafindratsima, Stephen; Guérin, Roger; Bendjoudi, Hocine; de Marsily, Ghislain

    2014-09-01

    A methodological approach is described which combines geophysical and geochemical data to delineate the extent of a chlorinated ethenes plume in northern France; the methodology was used to calibrate a hydrogeological model of the contaminants' migration and degradation. The existence of strong reducing conditions in some parts of the aquifer is first determined by measuring in situ the redox potential and dissolved oxygen, dissolved ferrous iron and chloride concentrations. Electrical resistivity imaging and electromagnetic mapping, using the Slingram method, are then used to determine the shape of the pollutant plume. A decreasing empirical exponential relation between measured chloride concentrations in the water and aquifer electrical resistivity is observed; the resistivity formation factor calculated at a few points also shows a major contribution of chloride concentration in the resistivity of the saturated porous medium. MODFLOW software and MT3D99 first-order parent-daughter chain reaction and the RT3D aerobic-anaerobic model for tetrachloroethene (PCE)/trichloroethene (TCE) dechlorination are finally used for a first attempt at modeling the degradation of the chlorinated ethenes. After calibration, the distribution of the chlorinated ethenes and their degradation products simulated with the model approximately reflects the mean measured values in the observation wells, confirming the data-derived image of the plume.

  5. Containment of subsurface contaminants

    DOEpatents

    Corey, John C.

    1994-01-01

    A barrier for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates.

  6. Containment of subsurface contaminants

    DOEpatents

    Corey, J.C.

    1994-09-06

    A barrier is disclosed for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates. 5 figs.

  7. Sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts

    USGS Publications Warehouse

    LeBlanc, Denis R.

    1984-01-01

    Secondarily treated domestic sewage has been disposed of on surface sand beds at the sewage treatment facility at Otis Air Force Base, Massachusetts, since 1936. Infiltration of the sewage through the sand beds into the underlying unconfined sand and gravel aquifer has resulted in a plume of sewage-contaminated ground water that is 2,500 to 3,500 feet wide, 75 feet thick, and more than 11,000 feet long. The plume extends south and southwest of the sand beds in the same direction as the regional flow of ground water, and is overlain by 20 to 50 feet of ground water derived from precipitation that recharges the aquifer. The bottom of the plume generally coincides with the contact between the permeable sand and gravel and underlying finer grained sediments. The distributions in the aquifer of specific conductance, temperature, boron, chloride, sodium, phosphorus, nitrogen (total of all species), ammonia, nitrate, dissolved oxygen, and detergents are used to delineate the plume. In ground water outside the plume, the detergent concentration is less than 0.1 milligrams per liter as MBAS (methylene blue active substances), the ammonia-nitrogen concentration is less than 0.1 milligrams per liter, the boron concentration is less than 50 micrograms per liter, and specific conductance is less than 80 mircromhos per centimeter. In the center of the plume, detergent concentrations as high as 2.6 milligrams per liter as MBAS, ammonia-nitrogen concentrations as high as 20 milligrams per liter, boron concentrations as high as 400 micrograms per liter, and specific conductance as high as 405 micromhos per centimeter were measured. Chloride, sodium, and boron are transported by the southward-flowing ground water without significant retardation, and seem to be diluted only by hydrodynamic dispersion. The movement of phosphorus is greatly restricted by sorption. Phosphorus concentrations do not exceed 0.05 milligrams per liter farther than 2,500 feet from the sand beds. Detergent

  8. Improving the delineation of hydrocarbon-impacted soils and water through induced polarization (IP) tomographies: a field study at an industrial waste land.

    PubMed

    Deceuster, John; Kaufmann, Olivier

    2012-08-01

    Without a good estimation of samples representativeness, the delineation of the contaminated plume extent and the evaluation of volumes of hydrocarbon-impacted soils may remain difficult. To contribute to this question, a time domain induced polarization (IP) field experiment was conducted on an industrial waste land. Boreholes were drilled to specify the local geological context. Cross-hole seismic tomographies were performed to extend borehole logs and to draw an interpreted geological cross-section. Soil samples taken during drillings were analysed in laboratory. A preliminary survey was conducted to locate the IP profile. The polarization signatures linked to the presence of clayey sediments were filtered out from the data set. Chargeability and resistivity depth soundings were computed and compared to mean concentrations of total organic products to overcome the data support issue between the geophysical models and the spot samples of soils. A logarithmic relation between chargeabilities and smoothed hydrocarbon concentrations in soils was found. Taking into account contaminant's concentration thresholds defined in local codes and regulations allows defining chargeability classes to delineate hotspots on this site. This showed that IP tomography can be an accurate screening methodology. A statistical methodology is proposed to assess the efficiency of the investigation strategy. PMID:22659399

  9. COOLING TOWER PLUME MODEL

    EPA Science Inventory

    A review of recently reported cooling tower plume models yields none that is universally accepted. The entrainment and drag mechanisms and the effect of moisture on the plume trajectory are phenomena which are treated differently by various investigators. In order to better under...

  10. Stealth Plumes on Io

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.; Matson, Dennis L.; Blaney, Diana L.; Veeder, Glenn J.; Davies, Ashley

    1995-01-01

    We suggest that Io's eruptive activity may include a class of previously undetected SO2 geysers. The thermodynamic models for the eruptive plumes discovered by Voyager 'involve low to moderate entropy SO2 eruptions. The resulting plumes are a mixture of solid and gas which emerge from the vent and follow essentially ballistic trajectories. We show that intrusion of silicate magma into buried SO2 deposits can create the required conditions for high entropy eruptions which proceed entirely in the vapor phase. These purely gaseous plumes would have been invisible to Voyager's instruments. Hence, we call them "stealth" plumes. Such eruptions could explain the "patchy" SO2 atmosphere inferred from recent UV and micro-wave spectral observations. The magma intrusion rate required to support the required gas production for these plumes is a negligible fraction of estimated global magma intrusion rates.

  11. Subsurface contaminants focus area

    SciTech Connect

    1996-08-01

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

  12. 30 CFR 282.22 - Delineation Plan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Delineation Plan. 282.22 Section 282.22 Mineral... § 282.22 Delineation Plan. All exploration activities shall be conducted in accordance with a Delineation Plan submitted by the lessee and approved by the Director. The Delineation Plan shall describe...

  13. Evidence for Little Shallow Entrainment in Starting Mantle Plumes

    NASA Astrophysics Data System (ADS)

    Lohmann, F. C.; Phipps Morgan, J.; Hort, M.

    2005-12-01

    Basalts from intraplate or hotspot ocean islands show distinct geochemical signatures. Their diversity in composition is generally believed to result from the upwelling plume entraining shallow mantle material during ascent, while potentially also entraining other deep regions of the mantle. Here we present results from analogue laboratory experiments and numerical modelling that there is evidence for little shallow entrainment into ascending mantle plumes, i.e. most of the plume signature is inherited from the source. We conducted laboratory experiments using glucose syrup contaminated with glass beads to visualize fluid flow and origin. The plume is initiated by heating from below or by injecting hot, uncontaminated syrup. Particle movement is captured by a CCD camera. In our numerical experiments we solve the Stokes equations for a viscous fluid at infinite Prandtl number with passive tracer particles being used to track fluid flow and entrainment rates, simulating laboratory as well as mantle conditions. In both analogue experiments and numerical models we observe the classical plume structure being embedded in a `sheath' of material from the plume source region that retains little of the original temperature anomaly of the plume source. Yet, this sheath ascends in the `slipstream' of the plume at speeds close to the ascent speed of the plume head, and effectively prevents the entrainment of surrounding material into the plume head or plume tail. We find that the source region is most effectively sampled by an ascending plume and that compositional variations in the source region are preserved during plume ascent. The plume center and plume sheath combined are composed of up to 85% source material. However, there is also evidence of significant entrainment of up to 30% of surrounding material into the outer layers of the plume sheath. Entrainment rates are found to be influenced by mantle composition and structure, with the radial viscosity profile of the

  14. Distribution of microbial physiologic types in an aquifer contaminated by crude oil

    USGS Publications Warehouse

    Bekins, B.A.; Godsy, E.M.; Warren, E.

    1999-01-01

    We conducted a plume-scale study of the microbial ecology in the anaerobic portion of an aquifer contaminated by crude-oil compounds. The data provide insight into the patterns of ecological succession, microbial nutrient demands, and the relative importance of free-living versus attached microbial populations. The most probable number (MPN) method was used to characterize the spatial distribution of six physiologic types: aerobes, denitrifiers, iron-reducers, heterotrophic fermenters, sulfate-reducers, and methanogens. Both free-living and attached numbers were determined over a broad cross-section of the aquifer extending horizontally from the source of the plume at a nonaqueous oil body to 66 m downgradient, and vertically from above the water table to the base of the plume below the water table. Point samples from widely spaced locations were combined with three closely spaced vertical profiles to create a map of physiologic zones for a cross-section of the plume. Although some estimates suggest that less than 1% of the subsurface microbial population can be grown in laboratory cultures, the MPN results presented here provide a comprehensive qualitative picture of the microbial ecology at the plume scale. Areas in the plume that are evolving from iron-reducing to methanogenic conditions are clearly delineated and generally occupy 25-50% of the plume thickness. Lower microbial numbers below the water table compared to the unsaturated zone suggest that nutrient limitations may be important in limiting growth in the saturated zone. Finally, the data indicate that an average of 15% of the total population is suspended.

  15. REFERENCE SITE WATERSHED DELINEATION PROJECT

    EPA Science Inventory

    The use of geographic information systems for the delineation of watersheds and analysis of land use / land cover associated with 250 reference sites on wadeable streams as identified by the Central Plains Bioassessment workgroup and located in the States of Kansas, Iowa, Missour...

  16. Prometheus: Io's wandering plume.

    PubMed

    Kieffer, S W; Lopes-Gautier, R; McEwen, A; Smythe, W; Keszthelyi, L; Carlson, R

    2000-05-19

    Unlike any volcanic behavior ever observed on Earth, the plume from Prometheus on Io has wandered 75 to 95 kilometers west over the last 20 years since it was first discovered by Voyager and more recently observed by Galileo. Despite the source motion, the geometric and optical properties of the plume have remained constant. We propose that this can be explained by vaporization of a sulfur dioxide and/or sulfur "snowfield" over which a lava flow is moving. Eruption of a boundary-layer slurry through a rootless conduit with sonic conditions at the intake of the melted snow can account for the constancy of plume properties. PMID:10817989

  17. Colloid Formation at Waste Plume Fronts

    SciTech Connect

    Wan, Jiamin; Tokunaga, Tetsu K.; Saiz, Eduardo; Larsen, Joern T.; Zheng, Zuoping; Couture, Rex A.

    2004-05-22

    Highly saline and caustic tank waste solutions containing radionuclides and toxic metals have leaked into sediments at U. S. Department of Energy (DOE) facilities such as the Hanford Site (Washington State). Colloid transport is frequently invoked to explain migration of radionuclides and metals in the subsurface. To understand colloid formation during interactions between highly reactive fluids and sediments and its impact on contaminant transport, we simulated tank waste solution (TWS) leakage processes in laboratory columns at ambient and elevated (70 C) temperatures. We found that maximum formation of mobile colloids occurred at the plume fronts (hundreds to thousands times higher than within the plume bodies or during later leaching). Concentrations of suspended solids were as high as 3 mass%, and their particle-sizes ranged from tens of nm to a few {micro}m. Colloid chemical composition and mineralogy depended on temperature. During infiltration of the leaked high Na{sup +} waste solution, rapid and completed Na{sup +} replacement of exchangeable Ca{sup 2+} and Mg{sup 2+} from the sediment caused accumulation of these divalent cations at the moving plume front. Precipitation of supersaturated Ca{sup 2+}/Mg{sup 2+}-bearing minerals caused dramatic pH reduction at the plume front. In turn, the reduced pH caused precipitation of other minerals. This understanding can help predict the behavior of contaminant trace elements carried by the tank waste solutions, and could not have been obtained through conventional batch studies.

  18. CHLORINATED SOLVENT PLUME CONTROL

    EPA Science Inventory

    This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

  19. Methane Plumes on Mars

    NASA Video Gallery

    Spectrometer instruments attached to several telescopes detect plumes of methane emitted from Mars during its summer and spring seasons. High levels of methane are indicated by warmer colors. The m...

  20. Sulfur plumes off Namibia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Sulfur plumes rising up from the bottom of the ocean floor produce colorful swirls in the waters off the coast of Namibia in southern Africa. The plumes come from the breakdown of marine plant matter by anaerobic bacteria that do not need oxygen to live. This image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite on April 24, 2002 Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  1. Electrification of volcanic plumes

    NASA Astrophysics Data System (ADS)

    Mather, T. A.; Harrison, R. G.

    2006-07-01

    Volcanic lightning, perhaps the most spectacular consequence of the electrification of volcanic plumes, has been implicated in the origin of life on Earth, and may also exist in other planetary atmospheres. Recent years have seen volcanic lightning detection used as part of a portfolio of developing techniques to monitor volcanic eruptions. Remote sensing measurement techniques have been used to monitor volcanic lightning, but surface observations of the atmospheric electric Potential Gradient (PG) and the charge carried on volcanic ash also show that many volcanic plumes, whilst not sufficiently electrified to produce lightning, have detectable electrification exceeding that of their surrounding environment. Electrification has only been observed associated with ash-rich explosive plumes, but there is little evidence that the composition of the ash is critical to its occurrence. Different conceptual theories for charge generation and separation in volcanic plumes have been developed to explain the disparate observations obtained, but the ash fragmentation mechanism appears to be a key parameter. It is unclear which mechanisms or combinations of electrification mechanisms dominate in different circumstances. Electrostatic forces play an important role in modulating the dry fall-out of ash from a volcanic plume. Beyond the local electrification of plumes, the higher stratospheric particle concentrations following a large explosive eruption may affect the global atmospheric electrical circuit. It is possible that this might present another, if minor, way by which large volcanic eruptions affect global climate. The direct hazard of volcanic lightning to communities is generally low compared to other aspects of volcanic activity.

  2. Estuarine and coastal water dynamics controlling sediment movement and plume development in Long Island Sound

    NASA Technical Reports Server (NTRS)

    Ruggles, F. H., Jr. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. As the Connecticut River flows into Long Island Sound, large plumes develop during the mixing of ocean and estuarine waters. Plumes were delineated for July 28, October 8, October 27, and December 2, 1972, by analyzing ERTS-1 imagery with the SRI Electronic Satellite Image Analysis Console (ESIAC). Because the chemical and physical composition of the plume and ocean water were not too different, the ESIAC was utilized to expand the scenes and subject the transparencies to varying combinations of viewing techniques to identify and delineate the plumes. Best results were obtained when band 5 transparencies were used. Indications are, when the scene being analyzed is predominantly in the first two steps of the gray scale, it is best to use the negative transparencies. When the analysis is being done above the first two steps of the gray scale, it is best to use the positive transparencies.

  3. Large eddy simulation of plume dispersion in a convective boundary layer

    SciTech Connect

    Fosberry, L.P.; Tsang, T.T.H.

    1996-12-31

    Plume dispersion in a convective boundary layer is dependent on release height. When a neutrally buoyant contaminant is released from an elevated point in the convective boundary layer at z {approximately} 0.5h, where h is the height of the boundary layer, the plume descends and a concentration maximum is observed at ground level. Alternately, when the contaminant is released from a surface source at z < {approximately} 0.2h, the plume lifts off and a maximum concentration is observed near the inversion layer. Neutrally buoyant plume dispersion in the convective atmospheric boundary layer were simulated by a mixed pseudospectral finite difference Large Eddy Simulation (LES).

  4. Electrification of volcanic plumes

    NASA Astrophysics Data System (ADS)

    Mather, T. A.; Harrison, R. G.

    We present a review of our current understanding of the electrification of volcanic plumes on Earth and discuss the possible implications both in terms of the volcanic monitoring, early Earth evolution and planetary exploration. Volcanic lightning is perhaps the most spectacular consequence of the electrification of volcanic plumes. Recent years have seen volcanic lightning detection used as part of a portfolio of developing techniques to monitor volcanic eruptions. Remote sensing measurement techniques have been used to monitor volcanic lightning, but surface observations of the atmospheric electric Potential Gradient (PG) and the charge carried on volcanic ash also show that many volcanic plumes, whilst not sufficiently electrified to produce lightning, have detectable electrification exceeding that of their surrounding environment. Electrification has only been observed associated with ash-rich explosive plumes, but there is little evidence that the composition of the ash is critical to its occurrence. Different conceptual theories for charge generation and separation in volcanic plumes have been developed to explain the disparate observations obtained, but the ash fragmentation mechanism appears to be a key parameter. It is unclear which mechanisms or combinations of electrification mechanisms dominate in different circumstances. Electrostatic forces play an important role in modulating the dry fall-out of ash from a volcanic plume. Beyond the local electrification of plumes, the higher stratospheric particle concentrations following a large explosive eruption may affect the global atmospheric electrical circuit. It is possible that this might present another, if minor, way by which large volcanic eruptions affect global climate. Volcanic lightning has been implicated in a number of ways in the origin of life on Earth, and may also exist in other planetary atmospheres where measurements of its occurrence might give clues about the nature of volcanism on other

  5. River plume patterns and dynamics within the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Warrick, J. A.; DiGiacomo, P. M.; Weisberg, S. B.; Nezlin, N. P.; Mengel, M.; Jones, B. H.; Ohlmann, J. C.; Washburn, L.; Terrill, E. J.; Farnsworth, K. L.

    2007-11-01

    Stormwater river plumes are important vectors of marine contaminants and pathogens in the Southern California Bight. Here we report the results of a multi-institution investigation of the river plumes across eight major river systems of southern California. We use in situ water samples from multi-day cruises in combination with MODIS satellite remote sensing, buoy meteorological observations, drifters, and HF radar current measurements to evaluate the dispersal patterns and dynamics of the freshwater plumes. River discharge was exceptionally episodic, and the majority of storm discharge occurred in a few hours. The combined plume observing techniques revealed that plumes commonly detach from the coast and turn to the left, which is the opposite direction of Coriolis influence. Although initial offshore velocity of the buoyant plumes was ˜50 cm/s and was influenced by river discharge inertia (i.e., the direct momentum of the river flux) and buoyancy, subsequent advection of the plumes was largely observed in an alongshore direction and dominated by local winds. Due to the multiple day upwelling wind conditions that commonly follow discharge events, plumes were observed to flow from their respective river mouths to down-coast waters at rates of 20-40 km/d. Lastly, we note that suspended-sediment concentration and beam-attenuation were poorly correlated with plume salinity across and within the sampled plumes (mean r2=0.12 and 0.25, respectively), while colored dissolved organic matter (CDOM) fluorescence was well correlated (mean r2=0.56), suggesting that CDOM may serve as a good tracer of the discharged freshwater in subsequent remote sensing and monitoring efforts of plumes.

  6. A Brilliant Plume

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Long Range Reconnaissance Imager (LORRI) on New Horizons captured another dramatic picture of Jupiter's moon Io and its volcanic plumes, 19 hours after the spacecraft's closest approach to Jupiter on Feb. 28, 2007. LORRI took this 75 millisecond exposure at 0035 Universal Time on March 1, 2007, when Io was 2.3 million kilometers (1.4 million miles) from the spacecraft.

    Io's dayside is deliberately overexposed to bring out faint details in the plumes and on the moon's night side. The continuing eruption of the volcano Tvashtar, at the 1 o'clock position, produces an enormous plume roughly 330 kilometers (200 miles) high, which is illuminated both by sunlight and 'Jupiter light.'

    The shadow of Io, cast by the Sun, slices across the plume. The plume is quite asymmetrical and has a complicated wispy texture, for reasons that are still mysterious. At the heart of the eruption incandescent lava, seen here as a brilliant point of light, is reminding scientists of the fire fountains spotted by the Galileo Jupiter orbiter at Tvashtar in 1999.

    The sunlit plume faintly illuminates the surface underneath. 'New Horizons and Io continue to astonish us with these unprecedented views of the solar system's most geologically active body' says John Spencer, deputy leader of the New Horizons Jupiter Encounter Science Team and an Io expert from Southwest Research Institute.

    Because this image shows the side of Io that faces away from Jupiter, the large planet does not illuminate the moon's night side except for an extremely thin crescent outlining the edge of the disk at lower right. Another plume, likely from the volcano Masubi, is illuminated by Jupiter just above this lower right edge. A third and much fainter plume, barely visible at the 2 o'clock position, could be the first plume seen from the volcano Zal Patera.

    As in other New Horizons images of Io, mountains catch the setting Sun just beyond the terminator (the line dividing day and night

  7. Review of quantitative surveys of the length and stability of MTBE, TBA, and benzene plumes in groundwater at UST sites.

    PubMed

    Connor, John A; Kamath, Roopa; Walker, Kenneth L; McHugh, Thomas E

    2015-01-01

    Quantitative information regarding the length and stability condition of groundwater plumes of benzene, methyl tert-butyl ether (MTBE), and tert-butyl alcohol (TBA) has been compiled from thousands of underground storage tank (UST) sites in the United States where gasoline fuel releases have occurred. This paper presents a review and summary of 13 published scientific surveys, of which 10 address benzene and/or MTBE plumes only, and 3 address benzene, MTBE, and TBA plumes. These data show the observed lengths of benzene and MTBE plumes to be relatively consistent among various regions and hydrogeologic settings, with median lengths at a delineation limit of 10 µg/L falling into relatively narrow ranges from 101 to 185 feet for benzene and 110 to 178 feet for MTBE. The observed statistical distributions of MTBE and benzene plumes show the two plume types to be of comparable lengths, with 90th percentile MTBE plume lengths moderately exceeding benzene plume lengths by 16% at a 10-µg/L delineation limit (400 feet vs. 345 feet) and 25% at a 5-µg/L delineation limit (530 feet vs. 425 feet). Stability analyses for benzene and MTBE plumes found 94 and 93% of these plumes, respectively, to be in a nonexpanding condition, and over 91% of individual monitoring wells to exhibit nonincreasing concentration trends. Three published studies addressing TBA found TBA plumes to be of comparable length to MTBE and benzene plumes, with 86% of wells in one study showing nonincreasing concentration trends. PMID:25040137

  8. Stochastic analytical modeling of the biodegradation of steady plumes

    NASA Astrophysics Data System (ADS)

    Zarlenga, A.; Fiori, A.

    2014-02-01

    We present a stochastic analytical framework to assess the contaminant concentration of a steady plume undergoing biodegradation. The method is focused on heterogeneous formations, and it embeds both fringe and core degradation. The Lagrangian concentration approach of Fiori (2001) was employed, which is suited for describing the interplay between the large scale advection caused by heterogeneity and the local dispersion processes. The principal scope of the model is to provide a relatively simple tool for a quick assessment of the contamination level in aquifers, as function of a few relevant, physically based dimensionless parameters. The solution of the analytical model is relatively simple and generalizes previous approaches developed for homogeneous formations. It is found that heterogeneity generally enhances mixing and degradation; in fact, the plume shear and distortion operated by the complex, heterogeneous velocity field facilitates local dispersion in diluting the contaminant and mixing it with the electron acceptor. The decay of the electron donor concentration, and so the plume length, is proportional to the transverse pore-scale dispersivity, which is indeed the parameter ruling mixing and hence degradation. While the theoretical plume length is controlled by the fringe processes, the core degradation may determine a significant decay of concentration along the mean flow direction, thus affecting the length of the plume. The method is applied to the crude oil contamination event at the Bemijdi site, Minnesota (USA).

  9. Nested monitoring approaches to delineate groundwater trichloroethene discharge to a UK lowland stream at multiple spatial scales

    NASA Astrophysics Data System (ADS)

    Weatherill, John; Krause, Stefan; Voyce, Kevin; Drijfhout, Falko; Levy, Amir; Cassidy, Nigel

    2014-03-01

    Integrated approaches for the identification of pollutant linkages between aquifers and streams are of crucial importance for evaluating the environmental risks posed by industrial contaminants like trichloroethene (TCE). This study presents a systematic, multi-scale approach to characterising groundwater TCE discharge to a 'gaining' UK lowland stream receiving baseflow from a major Permo-Triassic sandstone aquifer. Beginning with a limited number of initial monitoring points, we aim to provide a 'first pass' mechanistic understanding of the plume's fate at the aquifer/stream interface using a novel combination of streambed diffusion samplers, riparian monitoring wells and drive-point mini-piezometers in a spatially nested sampling configuration. Our results indicate the potential discharge zone of the plume to extend along a stream reach of 120 m in length, delineated by a network of 60 in-situ diffusion samplers. Within this section, a 40 m long sub-reach of higher concentration (> 10 μg L- 1) was identified; centred on a meander bend in the floodplain. 25 multi-level mini-piezometers installed to target this down-scaled reach revealed even higher TCE concentrations (20-40 μg L- 1), significantly above alluvial groundwater samples (< 6 μg L- 1) from 15 riparian monitoring wells. Significant lateral and vertical spatial heterogeneity in TCE concentrations within the top 1 m of the streambed was observed with the decimetre-scale vertical resolution provided by multi-level mini-piezometers. It appears that the distribution of fine-grained material in the Holocene deposits of the riparian floodplain and below the channel is exerting significant local-scale geological controls on the location and magnitude of the TCE discharge. Large-scale in-situ biodegradation of the plume was not evident during the monitoring campaigns. However, detections of cis-1,2-dichloroethene and vinyl chloride in discrete sections of the sediment profile indicate that shallow (e.g., < 20

  10. Nested monitoring approaches to delineate groundwater trichloroethene discharge to a UK lowland stream at multiple spatial scales.

    PubMed

    Weatherill, John; Krause, Stefan; Voyce, Kevin; Drijfhout, Falko; Levy, Amir; Cassidy, Nigel

    2014-03-01

    Integrated approaches for the identification of pollutant linkages between aquifers and streams are of crucial importance for evaluating the environmental risks posed by industrial contaminants like trichloroethene (TCE). This study presents a systematic, multi-scale approach to characterising groundwater TCE discharge to a 'gaining' UK lowland stream receiving baseflow from a major Permo-Triassic sandstone aquifer. Beginning with a limited number of initial monitoring points, we aim to provide a 'first pass' mechanistic understanding of the plume's fate at the aquifer/stream interface using a novel combination of streambed diffusion samplers, riparian monitoring wells and drive-point mini-piezometers in a spatially nested sampling configuration. Our results indicate the potential discharge zone of the plume to extend along a stream reach of 120 m in length, delineated by a network of 60 in-situ diffusion samplers. Within this section, a 40 m long sub-reach of higher concentration (>10 μg L(-1)) was identified; centred on a meander bend in the floodplain. 25 multi-level mini-piezometers installed to target this down-scaled reach revealed even higher TCE concentrations (20-40 μg L(-1)), significantly above alluvial groundwater samples (<6 μg L(-1)) from 15 riparian monitoring wells. Significant lateral and vertical spatial heterogeneity in TCE concentrations within the top 1m of the streambed was observed with the decimetre-scale vertical resolution provided by multi-level mini-piezometers. It appears that the distribution of fine-grained material in the Holocene deposits of the riparian floodplain and below the channel is exerting significant local-scale geological controls on the location and magnitude of the TCE discharge. Large-scale in-situ biodegradation of the plume was not evident during the monitoring campaigns. However, detections of cis-1,2-dichloroethene and vinyl chloride in discrete sections of the sediment profile indicate that shallow (e.g., <20

  11. Collapse in Thermal Plumes

    NASA Astrophysics Data System (ADS)

    Pears, M. I.; Lithgow-Bertelloni, C. R.; Dobson, D. P.; Davies, R.

    2013-12-01

    Collapsing thermal plumes have been investigated through experimental and numerical simulations. Collapsing plumes are an uncommon fluid dynamical phenomenon, usually seen when the buoyancy source is turned off. A series of fluid dynamical experiments were conducted on thermal plumes at a variety of temperature and viscosity contrasts, in a 26.5 cm^3 cubic tank heated by a constant temperature heater 2 cm in diameter and no-slip bottom and top surfaces. Working fluids included Lyle's Golden Syrup and ADM's Liquidose 436 syrup, which have strongly-temperature dependent viscosity and high Pr number (10^3-10^7 at experimental conditions). Visualisation included white light shadowgraphs and PIV of the central plane. Temperature contrasts ranged from 3-60°C, and two differing forms of collapse were identified. At very low temperature differences 'no rise' collapse was discovered, where the plumes stagnate in the lower third of the tank before collapsing. At temperature differences between 10-23°C normal evolution occurred until 'lens shape' collapse developed between midway and two-thirds of the distance from the base. The lens shape originated in the top of the conduit and was present throughout collapse. At temperatures above ΔT=23°C the plumes follow the expected growth and shape and flatten out at the top of the tank. Thermal collapse remains difficult to explain given experimental conditions (continuous heating). Instead it is possible that small density differences arising from crystallization at ambient temperatures changes plume buoyancy-inducing collapse. We show results on the evolution of the refractive index of the syrup through time to ascertain this possibility. Preliminary numerical results using Fluidity will be presented to explore a greater parameter range of viscosity contrasts and tank aspect ratios.

  12. Io Pele plume

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Voyager 1 took this narrow-angle camera image on 5 March 1979 from a distance of 450,000 kilometers. At this geometry, the camera looks straight down through a volcanic plume at one of Io's most active volcanos, Pele. The large heart-shaped feature is the region where Pele's plume falls to the surface. At the center of the 'heart' is the small dark fissure that is the source of the eruption. The Voyager Project is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science.

  13. Evidence for mantle plumes?

    PubMed

    Anderson, Don L; Natland, James H

    2007-11-22

    Geophysical hotspots have been attributed to partially molten asthenosphere, fertile blobs, small-scale convection and upwellings driven by core heat. Most are short-lived or too close together to be deeply seated, and do not have anomalous heat flow or temperature; many are related to tectonic features. Bourdon et al. investigate the dynamics of mantle plumes from uranium-series geochemistry and interpret their results as evidence for thermal plumes. Here we show why alternative mechanisms of upwelling and melting should be considered. PMID:18033248

  14. In-situ remediation system and method for contaminated groundwater

    DOEpatents

    Corey, J.C.; Looney, B.B.; Kaback, D.S.

    1989-05-23

    A system for removing volatile contaminants from a subsurface plume of contamination comprising two sets of wells, a well for injecting a fluid into a saturated zone on one side of the plume and an extracting well for collecting the fluid together with volatilized contaminants from the plume on the other side of the plume. The fluid enables the volatile contaminants to be volatilized and carried therewith through the ground to the extracting well. Injecting and extracting wells are preferably horizontal wells positioned below the plume in the saturated zone and above the plume in the vadose zone, respectively. The fluid may be air or other gas or a gas and liquid mixture depending on the type of contaminant to be removed and may be preheated to facilitate volatilization. Treatment of the volatilized contamination may be by filtration, incineration, atmospheric dispersion or the like. 3 figs.

  15. In-situ remediation system and method for contaminated groundwater

    DOEpatents

    Corey, John C.; Looney, Brian B.; Kaback, Dawn S.

    1989-01-01

    A system for removing volatile contaminants from a subsurface plume of contamination comprising two sets of wells, a well for injecting a fluid into a saturated zone on one side of the plume and an extracting well for collecting the fluid together with volatilized contaminants from the plume on the other side of the plume. The fluid enables the volatile contaminants to be volatilized and carried therewith through the ground to the extracting well. Injecting and extracting wells are preferably horizontal wells positioned below the plume in the saturated zone and above the plume in the vadose zone, respectively. The fluid may be air or other gas or a gas and liquid mixture depending on the type of contaminant to be removed and may be preheated to facilitate volatilization. Treatment of the volatilized contamination may be by filtration, incineration, atmospheric dispersion or the like.

  16. Biodegradation at Dynamic Plume Fringes: Mixing Versus Reaction Control

    NASA Astrophysics Data System (ADS)

    Cirpka, O. A.; Eckert, D.; Griebler, C.; Haberer, C.; Kürzinger, P.; Bauer, R.; Mellage, A.

    2014-12-01

    Biodegradation of continuously emitted plumes is known to be most pronounced at the plume fringe, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. Under steady-state conditions, physical mixing of contaminant and electron acceptor by transverse dispersion was shown to be the major bottleneck for biodegradation, with plume lengths scaling inversely with the bulk transverse dispersivity in quasi two-dimensional settings. Under these conditions, the presence of suitable microbes is essential but the biokinetic parameters do not play an important role. When the location of the plume shifts (caused, e.g., by a fluctuating groundwater table), however, the bacteria are no more situated at the plume fringe and biomass growth, decay, activation and deactivation determine the time lag until the fringe-controlled steady state is approached again. During this time lag, degradation is incomplete. The objective of the presented study was to analyze to which extent flow and transport dynamics diminish effectiveness of fringe-controlled biodegradation and which microbial processes and related biokinetic parameters determine the system response in overall degradation to hydraulic fluctuations. We performed experiments in quasi-two-dimensional flow through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth and maintenance (often subsumed as "biomass decay") microbial dormancy (that is, change into a metabolically inactive state) and

  17. Final report : results of the 2006-2007 investigation of potential contamination at the former CCC/USDA facility in Barnes, Kansas.

    SciTech Connect

    LaFreniere, L. M.; Environmental Science Division

    2008-08-28

    The 2006-2007 investigation of carbon tetrachloride and chloroform contamination at Barnes, Kansas, was conducted at the request of the Kansas Department of Health and Environment (KDHE). The Environmental Science Division of Argonne National Laboratory implemented the investigation on behalf of the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA). The overall goal of the investigation was to establish criteria for monitoring leading to potential site reclassification. The investigation objectives were to (1) determine the hydraulic gradient near the former CCC/USDA facility, (2) delineate the downgradient carbon tetrachloride plume, and (3) design and implement an expanded monitoring network at Barnes (Argonne 2006a).

  18. Biogeochemical evolution of a landfill leachate plume, Norman, Oklahoma.

    PubMed

    Cozzarelli, I M; Böhlke, J K; Masoner, J; Breit, G N; Lorah, M M; Tuttle, M L W; Jaeschke, J B

    2011-01-01

    Leachate from municipal landfills can create groundwater contaminant plumes that may last for decades to centuries. The fate of reactive contaminants in leachate-affected aquifers depends on the sustainability of biogeochemical processes affecting contaminant transport. Temporal variations in the configuration of redox zones downgradient from the Norman Landfill were studied for more than a decade. The leachate plume contained elevated concentrations of nonvolatile dissolved organic carbon (NVDOC) (up to 300 mg/L), methane (16 mg/L), ammonium (650 mg/L as N), iron (23 mg/L), chloride (1030 mg/L), and bicarbonate (4270 mg/L). Chemical and isotopic investigations along a 2D plume transect revealed consumption of solid and aqueous electron acceptors in the aquifer, depleting the natural attenuation capacity. Despite the relative recalcitrance of NVDOC to biodegradation, the center of the plume was depleted in sulfate, which reduces the long-term oxidation capacity of the leachate-affected aquifer. Ammonium and methane were attenuated in the aquifer relative to chloride by different processes: ammonium transport was retarded mainly by physical interaction with aquifer solids, whereas the methane plume was truncated largely by oxidation. Studies near plume boundaries revealed temporal variability in constituent concentrations related in part to hydrologic changes at various time scales. The upper boundary of the plume was a particularly active location where redox reactions responded to recharge events and seasonal water-table fluctuations. Accurately describing the biogeochemical processes that affect the transport of contaminants in this landfill-leachate-affected aquifer required understanding the aquifer's geologic and hydrodynamic framework. PMID:21314684

  19. Biogeochemical evolution of a landfill leachate plume, Norman, Oklahoma

    USGS Publications Warehouse

    Cozzarelli, Isabelle M.; Bohlke, Johnkarl F.; Masoner, Jason R.; Breit, George N.; Lorah, Michelle M.; Tuttle, Michele L.W.; Jaeschke, Jeanne B.

    2011-01-01

    Leachate from municipal landfills can create groundwater contaminant plumes that may last for decades to centuries. The fate of reactive contaminants in leachate-affected aquifers depends on the sustainability of biogeochemical processes affecting contaminant transport. Temporal variations in the configuration of redox zones downgradient from the Norman Landfill were studied for more than a decade. The leachate plume contained elevated concentrations of nonvolatile dissolved organic carbon (NVDOC) (up to 300 mg/L), methane (16 mg/L), ammonium (650 mg/L as N), iron (23 mg/L), chloride (1030 mg/L), and bicarbonate (4270 mg/L). Chemical and isotopic investigations along a 2D plume transect revealed consumption of solid and aqueous electron acceptors in the aquifer, depleting the natural attenuation capacity. Despite the relative recalcitrance of NVDOC to biodegradation, the center of the plume was depleted in sulfate, which reduces the long-term oxidation capacity of the leachate-affected aquifer. Ammonium and methane were attenuated in the aquifer relative to chloride by different processes: ammonium transport was retarded mainly by physical interaction with aquifer solids, whereas the methane plume was truncated largely by oxidation. Studies near plume boundaries revealed temporal variability in constituent concentrations related in part to hydrologic changes at various time scales. The upper boundary of the plume was a particularly active location where redox reactions responded to recharge events and seasonal water-table fluctuations. Accurately describing the biogeochemical processes that affect the transport of contaminants in this landfill-leachate-affected aquifer required understanding the aquifer's geologic and hydrodynamic framework.

  20. Hydrostatic Modeling of Buoyant Plumes

    NASA Astrophysics Data System (ADS)

    Stroman, A.; Dewar, W. K.; Wienders, N.; Deremble, B.

    2014-12-01

    The Deepwater Horizon oil spill in the Gulf of Mexico has led to increased interest in understanding point source convection dynamics. Most of the existing oil plume models use a Lagrangian based approach, which computes integral measures such as plume centerline trajectory and plume radius. However, this approach doesn't account for feedbacks of the buoyant plume on the ambient environment. Instead, we employ an Eulerian based approach to acquire a better understanding of the dynamics of buoyant plumes. We have performed a series of hydrostatic modeling simulations using the MITgcm. Our results show that there is a dynamical response caused by the presence of the buoyant plume, in that there is a modification of the background flow. We find that the buoyant plume becomes baroclinically unstable and sheds eddies at the neutral buoyancy layer. We also explore different scenarios to determine the effect of the buoyancy source and the temperature stratification on the evolution of buoyant plumes.

  1. LAMP Observes the LCROSS Plume

    NASA Video Gallery

    This video shows LAMP’s view of the LCROSS plume. The first half of the animation shows the LAMP viewport scanning across the horizon, passing through the plume, and moving on. The second half of...

  2. Information Content of Turbulent Chemical Plumes

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Roberts, P. J. W.; Rahman, S.; Dasi, L. P.

    1999-11-01

    The rapid decrease in concentration contaminants released into the natural environment due to turbulent diffusion has traditionally been modeled based on time-averaged quantities. In contrast to the time-averaged concentration characteristics, the instantaneous characteristics and information content are poorly understood. Instantaneous peak levels are important in many contexts, including the impact of contaminants on organisms and the local ecosystem. The current work is motivated by the need to understand how aquatic organisms, such as blue crabs, search for and locate turbulent chemical odor plume sources. A fundamental question is what information is available to an animal or observer indicating its relative position to the plume source. In this study, the chemical plume is released iso-kinetically into a fully-developed, uniform open channel flow at 50 mm/s. Instantaneous concentration and velocity fields are simultaneously measured using planar laser induced fluorescence (PLIF) and digital particle tracking velocimetry (DPTV), respectively. In addition to the mean and variance, quantities of interest include intermittency, the temporal rise slope of chemical concentration and spatial correlations.

  3. Buoyant plume calculations

    SciTech Connect

    Penner, J.E.; Haselman, L.C.; Edwards, L.L.

    1985-01-01

    Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change, depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943 and a smaller scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of water-laden ground level air being carried to high altitude with the convection column as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions as well as the fire intensity. Little smoke is injected into the stratosphere unless the fire is unusually intense, or atmospheric conditions are more unstable than we have assumed. For intense fires significant amounts of water vapor are condensed raising the possibility of early scavenging of smoke particles by precipitation. 26 references, 11 figures.

  4. PLUME and research sotware

    NASA Astrophysics Data System (ADS)

    Baudin, Veronique; Gomez-Diaz, Teresa

    2013-04-01

    The PLUME open platform (https://www.projet-plume.org) has as first goal to share competences and to value the knowledge of software experts within the French higher education and research communities. The project proposes in its platform the access to more than 380 index cards describing useful and economic software for this community, with open access to everybody. The second goal of PLUME focuses on to improve the visibility of software produced by research laboratories within the higher education and research communities. The "development-ESR" index cards briefly describe the main features of the software, including references to research publications associated to it. The platform counts more than 300 cards describing research software, where 89 cards have an English version. In this talk we describe the theme classification and the taxonomy of the index cards and the evolution with new themes added to the project. We will also focus on the organisation of PLUME as an open project and its interests in the promotion of free/open source software from and for research, contributing to the creation of a community of shared knowledge.

  5. COLD WEATHER PLUME STUDY

    EPA Science Inventory

    While many studies of power plant plume transport and transformation have been performed during the summer, few studies of these processes during the winter have been carried out. Accordingly, the U.S. Environmental Protection Agency and the Electric Power Research Institute join...

  6. Improving operational plume forecasts

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-04-01

    Forecasting how plumes of particles, such as radioactive particles from a nuclear disaster, will be transported and dispersed in the atmosphere is an important but computationally challenging task. During the Fukushima nuclear disaster in Japan, operational plume forecasts were produced each day, but as the emissions continued, previous emissions were not included in the simulations used for forecasts because it became impractical to rerun the simulations each day from the beginning of the accident. Draxler and Rolph examine whether it is possible to improve plume simulation speed and flexibility as conditions and input data change. The authors use a method known as a transfer coefficient matrix approach that allows them to simulate many radionuclides using only a few generic species for the computation. Their simulations work faster by dividing the computation into separate independent segments in such a way that the most computationally time consuming pieces of the calculation need to be done only once. This makes it possible to provide real-time operational plume forecasts by continuously updating the previous simulations as new data become available. They tested their method using data from the Fukushima incident to show that it performed well. (Journal of Geophysical Research-Atmospheres, doi:10.1029/2011JD017205, 2012)

  7. Enceladus' Water Vapour Plumes

    NASA Technical Reports Server (NTRS)

    Hansen, Candice J.; Esposito, L.; Colwell, J.; Hendrix, A.; Matson, Dennis; Parkinson, C.; Pryor, W.; Shemansky, D.; Stewart, I.; Tew, J.; Yung, Y.

    2006-01-01

    A viewgraph presentation on the discovery of Enceladus water vapor plumes is shown. Conservative modeling of this water vapor is also presented and also shows that Enceladus is the source of most of the water required to supply the neutrals in Saturn's system and resupply the E-ring against losses.

  8. Stormwater plume detection by MODIS imagery in the southern California coastal ocean

    NASA Astrophysics Data System (ADS)

    Nezlin, Nikolay P.; DiGiacomo, Paul M.; Diehl, Dario W.; Jones, Burton H.; Johnson, Scott C.; Mengel, Michael J.; Reifel, Kristen M.; Warrick, Jonathan A.; Wang, Menghua

    2008-10-01

    Stormwater plumes in the southern California coastal ocean were detected by MODIS-Aqua satellite imagery and compared to ship-based data on surface salinity and fecal indicator bacterial (FIB) counts collected during the Bight'03 Regional Water Quality Program surveys in February-March of 2004 and 2005. MODIS imagery was processed using a combined near-infrared/shortwave-infrared (NIR-SWIR) atmospheric correction method, which substantially improved normalized water-leaving radiation (nLw) optical spectra in coastal waters with high turbidity. Plumes were detected using a minimum-distance supervised classification method based on nLw spectra averaged within the training areas, defined as circular zones of 1.5-5.0-km radii around field stations with a surface salinity of S < 32.0 ("plume") and S > 33.0 ("ocean"). The plume optical signatures (i.e., the nLw differences between "plume" and "ocean") were most evident during the first 2 days after the rainstorms. To assess the accuracy of plume detection, stations were classified into "plume" and "ocean" using two criteria: (1) "plume" included the stations with salinity below a certain threshold estimated from the maximum accuracy of plume detection; and (2) FIB counts in "plume" exceeded the California State Water Board standards. The salinity threshold between "plume" and "ocean" was estimated as 32.2. The total accuracy of plume detection in terms of surface salinity was not high (68% on average), seemingly because of imperfect correlation between plume salinity and ocean color. The accuracy of plume detection in terms of FIB exceedances was even lower (64% on average), resulting from low correlation between ocean color and bacterial contamination. Nevertheless, satellite imagery was shown to be a useful tool for the estimation of the extent of potentially polluted plumes, which was hardly achievable by direct sampling methods (in particular, because the grids of ship-based stations covered only small parts of the

  9. Volcanic Plume Measurements with UAV (Invited)

    NASA Astrophysics Data System (ADS)

    Shinohara, H.; Kaneko, T.; Ohminato, T.

    2013-12-01

    Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

  10. Species separation in rocket exhaust plumes and analytic plume flow models

    NASA Astrophysics Data System (ADS)

    Koppenwallner, G.

    2001-08-01

    Species separation in the exhaust plume of control thrusters of satellites is of main importance for the contamination analysis. Contamination concerns mainly scientific instruments or sensitive surfaces.. In continuum fluid dynamics a multi- component gas mixture can be treated as mixture with mean properties and with a flow field independent composition. This basic feature of continuum flow ceases to be valid in the rarefied flow regimes. In this regime there are two main mechanism which cause a separation of species in the flow field. a. Strong velocity gradients or streamline curvature. Strong stream line curvatures with large centrifugal forces exist close to the nozzle throat of sonic free jets [Sherman] or at the nozzle lip. Heavy gas constituents will not be able to follow these strong stream line curvatures. b. Different thermal velocity or thermal diffusivity of heavy and light gas constituents The transition from continuum to free molecular plume expansion can approximately be described by the sudden freeze model of Bird. At the freezing point molecular collisions suddenly cease and the further expansion is given by the velocity vector of the individual molecules at this freezing point. As light molecules have a larger thermal speed c than the heavy ones their spreading potential is also higher. This mechanism will also produce an enrichment of the plume boundary with light molecules. The approaches to model species separation in exhaust plumes as result of the above mechanism will be reviewed. To gain more insight into the separation the following cases are analyzed in detail: [B ]The free molecular supersonic expansion from a freezing plane. □ The various analytic plume flow models and their capability to predict the lateral spreading at the plume boundary (e.g. Simmons, Boynton, Brook, DLR) □ DSMC test case calculations of single and two-species plumes with mass separation. (M. Ivanov, ITAM) Based on this analysis a new 3 region model for species

  11. Ocean-outfall mixing zone delineation using Doppler radar

    SciTech Connect

    Chin, D.A.; Ding, L.; Huang, H.

    1997-12-01

    A methodology has been developed to use data collected by ocean surface current radar (OSCR) systems to predict the fate and transport of pollutants released from ocean outfalls. The proposed OSCR-based transport model was validated at the Miami Central-District (MCD) outfall using data collected during the Southeast Florida Outfall Experiment 2 (SEFLOE 2). A comparison between the measured dye concentration versus distance from the outfall and the predictions of the OSCR-based transport model showed good agreement. A second validation test of the OSCR-based transport model compared the growth of variance versus time and diffusion coefficients versus length scale with the conventional Okubo diagrams for instantaneous tracer releases. This comparison indicated that the mixing characteristics simulated explicitly by the OSCR-based transport model are in good agreement with field measurements in the coastal ocean. Mixing zones based on worst-case and probabilistic criteria were delineated using the OSCR-based model. The results indicate that an OSCR-based transport model is a significant improvement over conventional models that are used to delineate mixing zones surrounding ocean outfalls with surfacing plumes. This claim is strongly supported by the field data collected during the SEFLOE 2 study in south Florida.

  12. Stormwater plume detection by MODIS imagery in the southern California coastal ocean

    USGS Publications Warehouse

    Nezlin, N.P.; DiGiacomo, P.M.; Diehl, D.W.; Jones, B.H.; Johnson, S.C.; Mengel, M.J.; Reifel, K.M.; Warrick, J.A.; Wang, M.

    2008-01-01

    Stormwater plumes in the southern California coastal ocean were detected by MODIS-Aqua satellite imagery and compared to ship-based data on surface salinity and fecal indicator bacterial (FIB) counts collected during the Bight'03 Regional Water Quality Program surveys in February-March of 2004 and 2005. MODIS imagery was processed using a combined near-infrared/shortwave-infrared (NIR-SWIR) atmospheric correction method, which substantially improved normalized water-leaving radiation (nLw) optical spectra in coastal waters with high turbidity. Plumes were detected using a minimum-distance supervised classification method based on nLw spectra averaged within the training areas, defined as circular zones of 1.5-5.0-km radii around field stations with a surface salinity of S 33.0 ('ocean'). The plume optical signatures (i.e., the nLw differences between 'plume' and 'ocean') were most evident during the first 2 days after the rainstorms. To assess the accuracy of plume detection, stations were classified into 'plume' and 'ocean' using two criteria: (1) 'plume' included the stations with salinity below a certain threshold estimated from the maximum accuracy of plume detection; and (2) FIB counts in 'plume' exceeded the California State Water Board standards. The salinity threshold between 'plume' and 'ocean' was estimated as 32.2. The total accuracy of plume detection in terms of surface salinity was not high (68% on average), seemingly because of imperfect correlation between plume salinity and ocean color. The accuracy of plume detection in terms of FIB exceedances was even lower (64% on average), resulting from low correlation between ocean color and bacterial contamination. Nevertheless, satellite imagery was shown to be a useful tool for the estimation of the extent of potentially polluted plumes, which was hardly achievable by direct sampling methods (in particular, because the grids of ship-based stations covered only small parts of the plumes detected via

  13. Geophysical detection of on-site wastewater plumes in the North Carolina Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Smith, Matthew

    Nonpoint source pollution (NPS) continues to be the leading cause of water quality degradation in the United States. On-site wastewater systems (OWS) contribute to NPS; however, due to the range of system designs and complexity of the subsurface, OWS contributions to groundwater pollution are not well understood. As the population of coastal North Carolina continues to increase, better methods to locate and characterize wastewater impacted groundwater are needed. Previous studies have demonstrated the ability of non-intrusive geophysical methods to provide high resolution information on various contaminants in different geologic settings. The goals of this study were to evaluate the utility of ground penetrating radar (GPR) and capacitively coupled resistivity (CCR) for detecting OWS components, delineating associated wastewater plumes, and monitoring temporal variations in groundwater quality. Cross-sectional and three dimensional (3D) geophysical surveys were conducted periodically over a one year period (February 2011--January 2012) at two schools utilizing OWS in the lower Neuse River Basin (NRB) in the North Carolina Coastal Plain (NCCP). Cores were collected at both study sites; as well as monthly groundwater depth, temperature, and specific conductivity measurements to better constrain the geophysical interpretations. Additionally, dissolved inorganic nitrogen (DIN) and Cl concentrations were monitored bi-monthly to assess nutrient transport at the sites. The 3D GPR surveys effectively located the wastewater drainage trenches at both sites, in close agreement with locations described in as-built OWS blueprints. Regression analysis of resistivity versus groundwater specific conductivity revealed an inverse relationship, suggesting resistivity ≤ 250 ohm.m was indicative of wastewater impacted groundwater at both sites. The 3D resistivity models identified regions of low resistivity beneath the drainfields relative to background values. Regression analysis of

  14. Chemical plume source localization.

    PubMed

    Pang, Shuo; Farrell, Jay A

    2006-10-01

    This paper addresses the problem of estimating a likelihood map for the location of the source of a chemical plume using an autonomous vehicle as a sensor probe in a fluid flow. The fluid flow is assumed to have a high Reynolds number. Therefore, the dispersion of the chemical is dominated by turbulence, resulting in an intermittent chemical signal. The vehicle is capable of detecting above-threshold chemical concentration and sensing the fluid flow velocity at the vehicle location. This paper reviews instances of biological plume tracing and reviews previous strategies for a vehicle-based plume tracing. The main contribution is a new source-likelihood mapping approach based on Bayesian inference methods. Using this Bayesian methodology, the source-likelihood map is propagated through time and updated in response to both detection and nondetection events. Examples are included that use data from in-water testing to compare the mapping approach derived herein with the map derived using a previously existing technique. PMID:17036813

  15. Simulation of two- and three-dimensional dense solute plume behavior with the the METROPOL-3 code

    SciTech Connect

    Oostrom, M.; Roberson, K.R.; Leijnse, A.

    1994-07-01

    Contaminant plumes emanating from waste disposal facilities are often denser than the ambient groundwater. These so-called dense plumes sink deeper into phreatic aquifers and may, under certain conditions, become unstable. The behavior of variable density, aqueous-phase contaminant plumes in saturated, homogeneous 2-D and 3-D intermediate-scale aquifer models was investigated with the finite element code METROPOL-3. The numerical results compare, in a quantitative sense, to previously reported laboratory-scale transport experiments. The simulations show that dense plumes are more likely to penetrate deeper into aquifers and eventually become unstable with increasing density differences between the leachate solution and the ambient groundwater, and other important parameters as the saturated hydraulic conductivity of the porous medium, leakage-rate of the contaminant solution, and source width. The significance of unstable behavior decreases with increasing dispersivity values. It was observed that 3-D flow patterns have a stable effect on sense contaminant plume behavior.

  16. Low altitude plume impingement handbook

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon D.

    1991-01-01

    Plume Impingement modeling is required whenever an object immersed in a rocket exhaust plume must survive or remain undamaged within specified limits, due to thermal and pressure environments induced by the plume. At high altitudes inviscid plume models, Monte Carlo techniques along with the Plume Impingement Program can be used to predict reasonably accurate environments since there are usually no strong flowfield/body interactions or atmospheric effects. However, at low altitudes there is plume-atmospheric mixing and potential large flowfield perturbations due to plume-structure interaction. If the impinged surface is large relative to the flowfield and the flowfield is supersonic, the shock near the surface can stand off the surface several exit radii. This results in an effective total pressure that is higher than that which exists in the free plume at the surface. Additionally, in two phase plumes, there can be strong particle-gas interaction in the flowfield immediately ahead of the surface. To date there have been three levels of sophistication that have been used for low altitude plume induced environment predictions. Level 1 calculations rely on empirical characterizations of the flowfield and relatively simple impingement modeling. An example of this technique is described by Piesik. A Level 2 approach consists of characterizing the viscous plume using the SPF/2 code or RAMP2/LAMP and using the Plume Impingement Program to predict the environments. A Level 3 analysis would consist of using a Navier-Stokes code such as the FDNS code to model the flowfield and structure during a single calculation. To date, Level 1 and Level 2 type analyses have been primarily used to perform environment calculations. The recent advances in CFD modeling and computer resources allow Level 2 type analysis to be used for final design studies. Following some background on low altitude impingement, Level 1, 2, and 3 type analysis will be described.

  17. Seismic Imaging of Mantle Plumes

    NASA Astrophysics Data System (ADS)

    Nataf, Henri-Claude

    The mantle plume hypothesis was proposed thirty years ago by Jason Morgan to explain hotspot volcanoes such as Hawaii. A thermal diapir (or plume) rises from the thermal boundary layer at the base of the mantle and produces a chain of volcanoes as a plate moves on top of it. The idea is very attractive, but direct evidence for actual plumes is weak, and many questions remain unanswered. With the great improvement of seismic imagery in the past ten years, new prospects have arisen. Mantle plumes are expected to be rather narrow, and their detection by seismic techniques requires specific developments as well as dedicated field experiments. Regional travel-time tomography has provided good evidence for plumes in the upper mantle beneath a few hotspots (Yellowstone, Massif Central, Iceland). Beneath Hawaii and Iceland, the plume can be detected in the transition zone because it deflects the seismic discontinuities at 410 and 660 km depths. In the lower mantle, plumes are very difficult to detect, so specific methods have been worked out for this purpose. There are hints of a plume beneath the weak Bowie hotspot, as well as intriguing observations for Hawaii. Beneath Iceland, high-resolution tomography has just revealed a wide and meandering plume-like structure extending from the core-mantle boundary up to the surface. Among the many phenomena that seem to take place in the lowermost mantle (or D''), there are also signs there of the presence of plumes. In this article I review the main results obtained so far from these studies and discuss their implications for plume dynamics. Seismic imaging of mantle plumes is still in its infancy but should soon become a turbulent teenager.

  18. Areal extent of a plume of mineralized water from a flowing artesian well in Dade County, Florida

    USGS Publications Warehouse

    Waller, Bradley G.

    1982-01-01

    A flowing artesian well that taps the Floridan aquifer at Chekika Hammock State Park is contaminating the overlying Biscayne aquifer with saline water. The plume of mineralized water extends approximately 7 miles southeast of the well and ranges in width from 1 to 2 miles. The areal extent of contamination in the primary plume is approximately 12 square miles. The principal ions contaminating the Biscayne aquifer are chloride, sodium, and sulfate. (USGS)

  19. Experimental insights on the development of buoyant plumes injected into a porous media

    NASA Astrophysics Data System (ADS)

    Lyu, Xiaoying; Woods, Andrew W.

    2016-01-01

    We describe a series of new laboratory experiments which examine the rise of a two-dimensional buoyancy-driven plume of freshwater through a porous layer initially saturated with aqueous saline solution. Measurements show that the plume head accounts for a constant fraction of about 0.7 of the buoyancy supplied at the source and that it grows as it rises through the porous layer. However, the morphology of the plume head becomes increasingly complex as the ratio of the injection speed to the buoyancy rise speed increases, with the fluid spreading laterally and developing localized buoyant fingers which intermingle with the ambient fluid. Behind the plume head, a tail of nearly constant width develops providing a pathway from the source to the plume head. These starting plume dynamics may be relevant for buoyancy-driven contaminant dispersal and also for the convection which develops during CO2 sequestration as CO2 dissolves into aquifer water.

  20. THE TREATMENT OF CONTAMINATED WATER AT REMEDIAL WOOD PRESERVING SITES

    EPA Science Inventory

    Contaminated groundwater and surface water have posed a great challenge in restoring wood preserving sites to beneficial use. Often contaminated groundwater plumes extend far beyond the legal property limits, adversely impacting drinking water supplies and crop lands. To contain,...

  1. Hydraulic gradient control for groundwater contaminant removal

    USGS Publications Warehouse

    Fisher, Atwood D.; Gorelick, S.M.

    1985-01-01

    The Rocky Mountain Arsenal near Denver, Colarado, U.S.A., is used as a realistic setting for a hypothetical test of a procedure that plans the hydraulic stabilization and removal of a groundwater contaminant plume. A two-stage planning procedure successfully selects the best wells and their optimal pumping/recharge schedules to contain the plume while a well or system of wells within the plume removes the contaminated water. In stage I, a combined groundwater flow and solute transport model is used to simulate contaminant removal under an assumed velocity field. The result is the approximated plume boundary location as a function of time. In stage II, a linear program, which includes a groundwater flow model as part of the set of constraints, determines the optimal well selection and their optimal pumping/recharge schedules by minimizing total pumping and recharge. The simulation-management model eliminates wells far from the plume perimeter and activates wells near the perimeter as the plume decreases in size. This successfully stablizes the hydraulic gradient during aquifer cleanup.The Rocky Mountain Arsenal near Denver, Colorado, USA, is used as a realistic setting for a hypothetical test of a procedure that plans the hydraulic stabilization and removal of a groundwater contaminant plume. A two-stage planning procedure successfully selects the best wells and their optimal pumping/recharge schedules to contain the plume while a well or system of wells within the plume removes the contaminated water. In stage I, a combined groundwater flow and solute transport model is used to simulate contaminant removal under an assumed velocity field. The result is the approximated plume boundary location as a function of time. In stage II, a linear program, which includes a groundwater flow model as part of the set of constraints, determines the optimal well selection and their optimal pumping/recharge schedules by minimizing total pumping and recharge. Refs.

  2. Hele-Shaw Experiments on Plume Stretching and Folding

    NASA Astrophysics Data System (ADS)

    Foster, M.; Mays, D. C.; Neupauer, R. M.

    2013-12-01

    Fluid mixing in laminar flow is important in a number of practical applications, including remediation of contaminated groundwater. Recent modeling studies have shown that mixing can be accelerated and amplified by imposing a flow that generates stretching and folding of an injected plume of treatment solution. Stretching and folding, in turn, results from engineered injection and extraction of clean water through an array of wells surrounding the treatment solution. This poster describes a series of experiments whose goal is to demonstrate plume stretching and folding in a Hele-Shaw apparatus. An initial plume of treatment solution is injected into the center of the Hele-Shaw apparatus, which is assumed to represent a zone of contaminated groundwater, with four wells spaced evenly around the treatment solution. In order to spread the treatment solution into the groundwater, the four wells perform a series of infusions and withdrawals that push and pull apart the plume of treatment solution. With the proper steps, it will be shown that the plume can be stretched and folded to greatly increase the reactive interface area between the treatment solution and the contaminated groundwater. Consideration is given to two qualitative differences with respect to previous modeling studies. First, constant volume is required by the no-flow boundary used at the edge of the Hele-Shaw cell; any pump that is withdrawing water must have a complementary pump adding water at the same rate. Second, in these experiments, mixing results from a physical process, namely Taylor dispersion, eliminating the uncertainty resulting from the need to assume dispersion mechanisms in numerical models. Therefore, these experiments further elucidate the benefits and challenges of imposing plume stretching and folding in systems (like aquifers) where dispersion is unavoidable, providing new insight into the required logistics of using this approach in groundwater treatment.

  3. The Green Propellant Infusion Mission Thruster Performance Testing for Plume Diagnostics

    NASA Technical Reports Server (NTRS)

    Deans, Matthew C.; Reed, Brian D.; Arrington, Lynn A.; Williams, George J.; Kojima, Jun J.; Kinzbach, McKenzie I.; McLean, Christopher H.

    2014-01-01

    The Green Propellant Infusion Mission (GPIM) is sponsored by NASA's Space Technology Mission Directorate (STMD) Technology Demonstration Mission (TDM) office. The goal of GPIM is to advance the technology readiness level of a green propulsion system, specifically, one using the monopropellant, AF-M315E, by demonstrating ground handling, spacecraft processing, and on-orbit operations. One of the risks identified for GPIM is potential contamination of sensitive spacecraft surfaces from the effluents in the plumes of AF-M315E thrusters. NASA Glenn Research Center (GRC) is conducting activities to characterize the effects of AF-M315E plume impingement and deposition. GRC has established individual plume models of the 22-N and 1-N thrusters that will be used on the GPIM spacecraft. The model simulations will be correlated with plume measurement data from Laboratory and Engineering Model 22-N, AF-M315E thrusters. The thrusters are currently being tested in a small rocket, altitude facility at NASA GRC. A suite of diagnostics, including Raman spectroscopy, Rayleigh spectroscopy, and Schlieren imaging are being used to acquire plume measurements of AF-M315E thrusters. Plume data will include temperature, velocity, relative density, and species concentration. The plume measurement data will be compared to the corresponding simulations of the plume model. The GRC effort will establish a data set of AF-M315E plume measurements and a plume model that can be used for future AF-M315E applications.

  4. Plume Characterization of a Laboratory Model 22 N GPIM Thruster via High-Frequency Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Williams, George J.; Kojima, Jun J.; Arrington, Lynn A.; Deans, Matthew C.; Reed, Brian D.; Kinzbach, McKenzie I.; McLean, Christopher H.

    2015-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the capability of a green propulsion system, specifically, one using the monopropellant, AF-M315E. One of the risks identified for GPIM is potential contamination of sensitive areas of the spacecraft from the effluents in the plumes of AF-M315E thrusters. Plume characterization of a laboratory-model 22 N thruster via optical diagnostics was conducted at NASA GRC in a space-simulated environment. A high-frequency pulsed laser was coupled with an electron-multiplied ICCD camera to perform Raman spectroscopy in the near-field, low-pressure plume. The Raman data yielded plume constituents and temperatures over a range of thruster chamber pressures and as a function of thruster (catalyst) operating time. Schlieren images of the near-field plume enabled calculation of plume velocities and revealed general plume structure of the otherwise invisible plume. The measured velocities are compared to those predicted by a two-dimensional, kinetic model. Trends in data and numerical results are presented from catalyst mid-life to end-of-life. The results of this investigation were coupled with the Raman and Schlieren data to provide an anchor for plume impingement analysis presented in a companion paper. The results of both analyses will be used to improve understanding of the nature of AF-M315E plumes and their impacts to GPIM and other future missions.

  5. The Milan photooxidant plume

    NASA Astrophysics Data System (ADS)

    PréVôT, André S. H.; Staehelin, Johannes; Kok, Gregory L.; Schillawski, Richard D.; Neininger, Bruno; Staffelbach, Thomas; Neftel, Albrecht; Wernli, Heini; Dommen, Josef

    1997-10-01

    In Switzerland, measurement campaigns including aircraft measurements were carried out in the summers of 1992 and 1993 as part of the Pollution and Meteorology (POLLUMET) study. Ozone (O3) concentrations, up to 185 ppb, with a large spatial variability were found south of the Alps in the afternoon. Comparison to measurements north of the Alps shows that these concentration levels are extraordinarily high for central Europe. Backward trajectories reveal that the highest O3 levels were found 4-5 hours downwind of Milan, Italy. The measurements suggest a reactive organic gas (ROG) sensitive O3 production regime 1-3 hours downwind in the plume, and a NOx (sum of nitrogen oxide (NO) and nitrogen dioxide (NO2)) limitation in air masses not affected by the Milan plume. Air masses originating north of Milan are probably close to the transition zone between the two photochemical regimes. This was found by using measurements of total odd nitrogen (NOy,), NO, NO2, formaldehyde (HCHO), and hydrogen peroxide (H2O2) yielding indicators for ROG and NOx sensitive O3 production. The slope of ozone versus NOz (=NOy-NOx: photochemical products of NOx) were markedly higher in NOx limited conditions (ΔO3/ΔNOz=13.6) than in air masses close to the transition zone (ΔO3/ΔNOz=4.2).

  6. Nuclear rocket plume studies

    NASA Astrophysics Data System (ADS)

    Hastings, Daniel

    1993-05-01

    A description and detailed computational analysis of a vortex cleaning system designed to remove radioactive material from the plumes of nuclear rockets is included. The proposed system is designed to remove both particulates and radioactive gaseous material from the plume. A two part computational model is used to examine the system's ability to remove particulates, and the results indicate that under some conditions, the system can remove over 99% of the particles in the flow. Two critical parameters which govern the effectiveness of the system are identified and the information necessary to estimate cleaning efficiencies for particles of known sizes and densities is provided. A simple steady analytical solution is also developed to examine the system's ability to remove gaseous radioactive material. This analysis, while inconclusive, suggests that the swirl rates necessary to achieve useful efficiencies are too high to be achieved in any practical manner. Therefore, this system is probably not suitable for use, with gaseous radioactive material. It was concluded that the system can cause negligible specific impulse losses, though there may be a substantial mass penalty associated with its use.

  7. Atmospheric chemistry in volcanic plumes

    PubMed Central

    von Glasow, Roland

    2010-01-01

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis. PMID:20368458

  8. Atmospheric chemistry in volcanic plumes.

    PubMed

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis. PMID:20368458

  9. PERMEABLE REACTIVE BARRIER TECHNOLOGIES FOR CONTAMINANT REMEDIATION

    EPA Science Inventory

    Environmental scientists are generally familiar with the concept of barriers for restricting the movement of contaminant plumes in ground water. Such barriers are typically constructed of highly impermeable emplacements of materials such as grouts, slurries, or sheet pilings to ...

  10. Formation, Dynamics, and Impact of Plasmaspheric Plumes

    NASA Astrophysics Data System (ADS)

    Goldstein, Jerry; Borovsky, Joseph; Foster, John; Carpenter, Donald

    2007-06-01

    Workshop on Plasmaspheric Drainage Plumes, Taos, New Mexico, 9-13 October 2006 Plasmaspheric plumes result from erosion of the plasmasphere. The Institute of Geophysics and Planetary Physics (IGPP) Workshop on Plasmaspheric Drainage Plumes was convened in Taos, N. M., on 9-13 October 2006 to examine outstanding questions about the formation and dynamics of plumes, and the impact of plumes on the near-Earth space environment (geospace). A second workshop on plasmaspheric drainage plumes is planned for late 2007.