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Sample records for oil dispersion models

  1. MODELING DISPERSANT INTERACTIONS WITH OIL SPILLS

    EPA Science Inventory

    EPA is developing a model called the EPA Research Object-Oriented Oil Spill Model (ERO3S) and associated databases to simulate the impacts of dispersants on oil slicks. Because there are features of oil slicks that align naturally with major concepts of object-oriented programmi...

  2. Oil dispersants

    SciTech Connect

    Flaherty, L.M.

    1989-01-01

    This book contains papers presented at a symposium of the American Society for Testing and Materials. The topics covered include: The effect of elastomers on the efficiency of oil spill dispersants; planning for dispersant use; field experience with dispersants for oil spills on land; and measurements on natural dispersion.

  3. The NET effect of dispersants - a critical review of testing and modelling of surface oil dispersion.

    PubMed

    Zeinstra-Helfrich, Marieke; Koops, Wierd; Murk, Albertinka J

    2015-11-15

    Application of chemical dispersants or mechanical dispersion on surface oil is a trade-off between surface effects (impact of floating oil) and sub-surface effects (impact of suspended oil). Making an informed decision regarding such response, requires insight in the induced change in fate and transport of the oil. We aim to identify how natural, chemical and mechanical dispersion could be quantified in oil spill models. For each step in the dispersion process, we review available experimental data in order to identify overall trends and propose an algorithm or calculation method. Additionally, the conditions for successful mechanical and chemical dispersion are defined. Two commonly identified key parameters in surface oil dispersion are: oil properties (viscosity and presence of dispersants) and mixing energy (often wind speed). Strikingly, these parameters play a different role in several of the dispersion sub-processes. This may explain difficulties in simply relating overall dispersion effectiveness to the individual parameters. PMID:26412415

  4. Water-in-Oil Microstructures Formed by Marine Oil Dispersants in a Model Crude Oil.

    PubMed

    Riehm, David A; Rokke, David J; McCormick, Alon V

    2016-04-26

    DOSS (dioctyl sodium sulfosuccinate), Tween 80, and Span 80, surfactants commonly used in marine crude oil spill dispersants, have been mixed into a model oil at a total surfactant concentration of 2 wt %, typical for dispersant-treated oil slicks. These surfactant-oil blends also contained 0.5-1.5 wt % synthetic seawater to enable formation of water-in-oil (W/O) microstructures. Trends in dynamic oil-seawater interfacial tension (IFT) as a function of surfactant blend composition are similar to those observed in prior work for crude oil treated with similar blends of these surfactants. In particular, Span 80-rich surfactant blends exhibit much slower initial dynamic IFT decline than DOSS-rich surfactant blends in both model oil and crude oil, and surfactant blends containing 50 wt % Tween 80 and a DOSS:Span 80 ratio near 1:1 produce ultralow IFT in the model oil (<10(-4) mN/m) just as similar surfactant blends do in crude oil. At all DOSS:Span 80 ratios, surfactant blends containing 50 wt % Tween 80 form clear solutions with seawater in the model oil. Cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) show that these solutions contain spherical W/O microstructures, the size and dispersity of which vary with surfactant blend composition and surfactant:seawater molar ratio. Span 80-rich microstructures exhibit high polydispersity index (PDI > 0.2) and large diameters (≥100 nm), whereas DOSS-rich microstructures exhibit smaller diameters (20-40 nm) and low polydispersity index (PDI < 0.1), indicating a narrow microstructure size distribution. The smaller diameters of DOSS-rich microstructures, as well as the fact that DOSS molecules, being oil-soluble, can diffuse to a bulk oil-water interface as monomers much faster than any of these microstructures, may explain why DOSS-rich blends adsorb to the oil-water interface more quickly than Span 80-rich blends, a phenomenon which has been linked in prior work to the higher effectiveness

  5. Web Interface for Modeling Fog Oil Dispersion During Training

    NASA Astrophysics Data System (ADS)

    Lozar, Robert C.

    2002-08-01

    Predicting the dispersion of military camouflage training materials-Smokes and Obscurants (SO)-is a rapidly improving science. The Defense Threat Reduction Agency (DTRA) developed the Hazard Prediction and Assessment Capability (HPAC), a software package that allows the modeling of the dispersion of several potentially detrimental materials. ERDC/CERL characterized the most commonly used SO material, fog oil in HPAC terminology, to predict the SO dispersion characteristics in various training scenarios that might have an effect on Threatened and Endangered Species (TES) at DoD installations. To make the configuration more user friendly, the researchers implemented an initial web-interface version of HPAC with a modifiable fog-oil component that can be applied at any installation in the world. By this method, an installation SO trainer can plan the location and time of fog oil training activities and is able to predict the degree to which various areas will be effected, particularly important in ensuring the appropriate management of TES on a DoD installation.

  6. Light Penetration in Seawater Polluted by Dispersed Oil: Results of Radiative Transfer Modelling

    NASA Astrophysics Data System (ADS)

    Haule, K.; Darecki, M.; Toczek, H.

    2015-11-01

    The downwelling light in seawater is shaped by natural seawater constituents as well as by some external substances which can occur locally and temporally. In this study we focused on dispersed oil droplets which can be found in seawater after an oil spill or in the consequence of intensive shipping, oil extraction and transportation. We applied our modified radiative transfer model based on Monte Carlo code to evaluate the magnitude of potential influence of dispersed oil droplets on the downwelling irradiance and the depth of the euphotic zone. Our model was validated on the basis of in situ measurements for natural (unpolluted) seawater in the Southern Baltic Sea, resulting in less than 5% uncertainty. The optical properties of dispersed Petrobaltic crude oil were calculated on the basis of Mie theory and involved into radiative transfer model. We found that the changes in downwelling light caused by dispersed oil depend on several factors such as oil droplet concentration, size distribution, and the penetration depth (i.e. vertical range of oil droplets occurrence below sea surface). Petrobaltic oil droplets of submicron sizes and penetration depth of 5 m showed a potentially detectable reduction in the depth of the euphotic zone of 5.5% at the concentration of only 10 ppb. Micrometer-sized droplets needed 10 times higher concentration to give a similar effect. Our radiative transfer model provided data to analyse and discuss the influence of each factor separately. This study contributes to the understanding of the change in visible light penetration in seawater affected by dispersed oil.

  7. Modeling filtration of dispersed crude oil droplets by the copepod Calanus finmarchicus.

    PubMed

    Nepstad, Raymond; Størdal, Ingvild Fladvad; Brönner, Ute; Nordtug, Trond; Hansen, Bjørn Henrik

    2015-04-01

    Oil droplets may form and disperse in the water column after an accidental spill of crude oil or petroleum products at sea. Micro-sized oil droplets may be available for filter feeding organisms, such as the copepod Calanus finmarchicus, which has been shown to filter oil droplets. In the present paper, a modeling approach was used to estimate potential ingestion amounts by copepod filtration of oil droplets. The new model was implemented in the OSCAR (Oil Spill Contingency and Response) software suite, and tested for a series of oil spill scenarios and key parameters. Among these, the size of the filtered droplets was found to be the most important factor influencing the model results. Given the assumptions and simplifications of the model, filtration of dispersed crude oil by C. finmarchicus was predicted to affect the fate of 1-40% of the total released oil mass, depending on the release scenario and parameter values used, with the lower end of that range being more probable in an actual spill situation. PMID:25636164

  8. Succinimide lubricating oil dispersant

    SciTech Connect

    Wisotsky, M.J.; Bloch, R.; Brownwell, D.W.; Chen, F.J.; Gutierrez, A.

    1987-08-11

    A lubricating oil composition is described exhibiting improved dispersancy in both gasoline and diesel engines comprising a major amount of lubricating oil and 0.5 to 10 weight percent of a dispersant, the dispersant being prepared in a sequential process comprising the steps of: (a) in a first step reacting an oil-soluble polyolefin succinic anhydride, the olefin being a C/sub 3/ or C/sub 4/ olefin and an alkylene polyamine of the formula H/sub 2/N(CH/sub 2/)/sub n/(NH(CH/sub 2/)/sub n/)/sub m/sup -// NH/sub 2/ wherein n is 2 or 3 and m is 0 to 10, in a molar ratio of about 1.0 to 2.2 moles of polyolefin succinic anhydride per mole of polyamine, and (b) reacting the product of step (a) with dicarboxylic acid anhydride selected from the group consisting of maleic anhydride and succinic anhydride in sufficient molar proportions to provide a total mole ratio of about 2,3 to 3.0 moles of anhydride compounds per mole of polyamine.

  9. Phase and sedimentation behavior of oil (octane) dispersions in the presence of model mineral aggregates.

    PubMed

    Gupta, Anju; Sender, Maximilian; Fields, Sarah; Bothun, Geoffrey D

    2014-10-15

    Adsorption of suspended particles to the interface of surfactant-dispersed oil droplets can alter emulsion phase and sedimentation behavior. This work examines the effects of model mineral aggregates (silica nanoparticle aggregates or SNAs) on the behavior of oil (octane)-water emulsions prepared using sodium bis(2-ethylhexyl) sulfosuccinate (DOSS). Experiments were conducted at different SNA hydrophobicities in deionized and synthetic seawater (SSW), and at 0.5mM and 2.5mM DOSS. SNAs were characterized by thermogravimetric analysis (TGA) and dynamic light scattering (DLS), and the emulsions were examined by optical and cryogenic scanning electron microscopy. In deionized water, oil-in-water emulsions were formed with DOSS and the SNAs did not adhere to the droplets or alter emulsion behavior. In SSW, water-in-oil emulsions were formed with DOSS and SNA-DOSS binding through cation bridging led to phase inversion to oil-in-water emulsions. Droplet oil-mineral aggregates (OMAs) were observed for hydrophilic SNAs, while hydrophobic SNAs yielded quickly sedimenting agglomerated OMAs. PMID:25172613

  10. A comprehensive viscosity model for micro magnetic particle dispersed in silicone oil

    NASA Astrophysics Data System (ADS)

    Jung, Im Doo; Kim, Moobum; Park, Seong Jin

    2016-04-01

    Magnetorheological behavior of micro magnetic particle dispersed in silicone oil has been characterized by a multiplied form of phenomenological models taking the effect of shear rate, powder volume fraction, temperature and magnetic flux density. Magnetorheological fluid samples with seven different particle volume fraction were prepared by adding ferrite particles in silicone base oil and their shear viscosity of fluid samples were measured under three different temperatures (40 °C, 70 °C, and 110 °C) and ten different magnetic flux density (0-100 mT). The fluid had an upper limit to the increase of viscosity under the effect of external magnetic field and the saturation values were dependent on the operating temperature, shear rate and volume fraction of magnetic powder. The rheological behaviors have been characterized by our developed model which can be very useful for the precise control of the magnetorheological fluid.

  11. Dispersion Modeling.

    ERIC Educational Resources Information Center

    Budiansky, Stephen

    1980-01-01

    This article discusses the need for more accurate and complete input data and field verification of the various models of air pollutant dispension. Consideration should be given to changing the form of air quality standards based on enhanced dispersion modeling techniques. (Author/RE)

  12. Kinetic modeling and half life study on bioremediation of crude oil dispersed by Corexit 9500.

    PubMed

    Zahed, Mohammad Ali; Aziz, Hamidi Abdul; Isa, Mohamed Hasnain; Mohajeri, Leila; Mohajeri, Soraya; Kutty, Shamsul Rahman Mohamed

    2011-01-30

    Hydrocarbon pollution in marine ecosystems occurs mainly by accidental oil spills, deliberate discharge of ballast waters from oil tankers and bilge waste discharges; causing site pollution and serious adverse effects on aquatic environments as well as human health. A large number of petroleum hydrocarbons are biodegradable, thus bioremediation has become an important method for the restoration of oil polluted areas. In this research, a series of natural attenuation, crude oil (CO) and dispersed crude oil (DCO) bioremediation experiments of artificially crude oil contaminated seawater was carried out. Bacterial consortiums were identified as Acinetobacter, Alcaligenes, Bacillus, Pseudomonas and Vibrio. First order kinetics described the biodegradation of crude oil. Under abiotic conditions, oil removal was 19.9% while a maximum of 31.8% total petroleum hydrocarbons (TPH) removal was obtained in natural attenuation experiment. All DCO bioreactors demonstrated higher and faster removal than CO bioreactors. Half life times were 28, 32, 38 and 58 days for DCO and 31, 40, 50 and 75 days for CO with oil concentrations of 100, 500, 1000 and 2000 mg/L, respectively. The effectiveness of Corexit 9500 dispersant was monitored in the 45 day study; the results indicated that it improved the crude oil biodegradation rate. PMID:21041026

  13. OIL SLICK DISPERSAL MECHANICS

    EPA Science Inventory

    This study investigates the spreading and dissolution behavior of small oil slicks formed from spills of 12 oils. The increases in area covered by the oils during spreading experiments were determined using photographic techniques. Spreading equations were derived and used to cor...

  14. Intercomparison of oil spill prediction models for accidental blowout scenarios with and without subsea chemical dispersant injection.

    PubMed

    Socolofsky, Scott A; Adams, E Eric; Boufadel, Michel C; Aman, Zachary M; Johansen, Øistein; Konkel, Wolfgang J; Lindo, David; Madsen, Mads N; North, Elizabeth W; Paris, Claire B; Rasmussen, Dorte; Reed, Mark; Rønningen, Petter; Sim, Lawrence H; Uhrenholdt, Thomas; Anderson, Karl G; Cooper, Cortis; Nedwed, Tim J

    2015-07-15

    We compare oil spill model predictions for a prototype subsea blowout with and without subsea injection of chemical dispersants in deep and shallow water, for high and low gas-oil ratio, and in weak to strong crossflows. Model results are compared for initial oil droplet size distribution, the nearfield plume, and the farfield Lagrangian particle tracking stage of hydrocarbon transport. For the conditions tested (a blowout with oil flow rate of 20,000 bbl/d, about 1/3 of the Deepwater Horizon), the models predict the volume median droplet diameter at the source to range from 0.3 to 6mm without dispersant and 0.01 to 0.8 mm with dispersant. This reduced droplet size owing to reduced interfacial tension results in a one to two order of magnitude increase in the downstream displacement of the initial oil surfacing zone and may lead to a significant fraction of the spilled oil not reaching the sea surface. PMID:26021288

  15. DISPERSANT EFFECTIVENESS ON OIL SPILLS - EMPIRICAL CORRELATIONS

    EPA Science Inventory

    When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In...

  16. EVALUATION OF OIL SPILL DISPERSANT TESTING REQUIREMENTS

    EPA Science Inventory

    The research program evaluates the cost effectiveness of the procedures for testing oil spill dispersants as specified in Annex X of the National Oil and Hazardous Substances Pollution Contingency Plan. The testing procedure is described in detail in the Standard Dispersant Effec...

  17. DISPERSIBILITY OF CRUDE OIL IN FRESH WATER

    EPA Science Inventory

    The effects of surfactant composition on the ability of chemical dispersants to disperse crude oil in fresh water were investigated. The objective of this research was to determine whether effective fresh water dispersants can be designed in case this technology is ever consider...

  18. Effects of Surface-Engineered Nanoparticle-Based Dispersants for Marine Oil Spills on the Model Organism Artemia franciscana

    PubMed Central

    2015-01-01

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50–1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25–50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25–75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms. PMID:24823274

  19. Effects of surface-engineered nanoparticle-based dispersants for marine oil spills on the model organism Artemia franciscana.

    PubMed

    Rodd, April L; Creighton, Megan A; Vaslet, Charles A; Rangel-Mendez, J Rene; Hurt, Robert H; Kane, Agnes B

    2014-06-01

    Fine particles are under active consideration as alternatives to chemical dispersants for large-scale petroleum spills. Fine carbon particles with engineered surface chemistry have been shown to stabilize oil-in-water emulsions, but the environmental impacts of large-scale particle introduction to the marine environment are unknown. Here we study the impact of surface-engineered carbon-black materials on brine shrimp (Artemia franciscana) as a model marine microcrustacean. Mortality was characterized at 50-1000 mg/L, and levels of heat shock protein 70 (hsp70) were characterized at sublethal particle concentrations (25-50 mg/L). Functionalized carbon black (CB) nanoparticles were found to be nontoxic at all concentrations, while hydrophobic (annealed) and as-produced CB induced adverse effects at high concentrations. CB was also shown to adsorb benzene, a model hydrocarbon representing the more soluble and toxic low-molecular weight aromatic fraction of petroleum, but the extent of adsorption was insufficient to mitigate benzene toxicity to Artemia in coexposure experiments. At lower benzene concentrations (25-75 mg/L), coexposure with annealed and as-produced CB increased hsp70 protein levels. This study suggests that surface functionalization for increased hydrophilicity can not only improve the performance of CB-based dispersants but also reduce their adverse environmental impacts on marine organisms. PMID:24823274

  20. Chemical dispersants: Oil biodegradation friend or foe?

    PubMed

    Rahsepar, Shokouh; Smit, Martijn P J; Murk, Albertinka J; Rijnaarts, Huub H M; Langenhoff, Alette A M

    2016-07-15

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodegradation by alkane and/or aromatic degrading bacterial culture in artificial seawater at different dispersant to oil ratios (DORs). Our results show that dispersant addition did not enhance oil biodegradation. At DOR 1:20, biodegradation was inhibited, especially when only the alkane degrading culture was present. With a combination of cultures, this inhibition was overcome after 10days. This indicates that initial inhibition of oil biodegradation can be overcome when different bacteria are present in the environment. We conclude that the observed inhibition is related to the enhanced dissolution of aromatic compounds into the water, inhibiting the alkane degrading bacteria. PMID:27156037

  1. Dispersivity as an oil reservoir rock characteristic

    SciTech Connect

    Menzie, D.E.; Dutta, S.

    1989-12-01

    The main objective of this research project is to establish dispersivity, {alpha}{sub d}, as an oil reservoir rock characteristic and to use this reservoir rock property to enhance crude oil recovery. A second objective is to compare the dispersion coefficient and the dispersivity of various reservoir rocks with other rock characteristics such as: porosity, permeability, capillary pressure, and relative permeability. The dispersivity of a rock was identified by measuring the physical mixing of two miscible fluids, one displacing the other in a porous medium. 119 refs., 27 figs., 12 tabs.

  2. TECHNIQUES FOR MIXING DISPERSANTS WITH SPILLED OIL

    EPA Science Inventory

    The effective use of some oil spill dispersants requires the addition of mixing energy to the dispersant-treated slick. Various methods of energy application have included the use of fire hose streams directed to the water surface, outboard motors mounted on work boats, and the f...

  3. Oil spill dispersants: boon or bane?

    PubMed

    Prince, Roger C

    2015-06-01

    Dispersants provide a reliable large-scale response to catastrophic oil spills that can be used when the preferable option of recapturing the oil cannot be achieved. By allowing even mild wave action to disperse floating oil into tiny droplets (<70 μm) in the water column, seabirds, reptiles, and mammals are protected from lethal oiling at the surface, and microbial biodegradation is dramatically increased. Recent work has clarified how dramatic this increase is likely to be: beached oil has an environmental residence of years, whereas dispersed oil has a half-life of weeks. Oil spill response operations endorse the concept of net environmental benefit, that any environmental costs imposed by a response technique must be outweighed by the likely benefits. This critical review discusses the potential environmental debits and credits from dispersant use and concludes that, in most cases, the potential environmental costs of adding these chemicals to a polluted area are likely outweighed by the much shorter residence time, and hence integrated environmental impact, of the spilled oil in the environment. PMID:25938731

  4. Toxicity of oil dispersant, crude oil and dispersed crude oil to a marine amphipod and gastropod

    SciTech Connect

    Gulec, I.; Holdway, D.A.

    1995-12-31

    The importance of appropriate oil spill remedial action was emphasized during the recent Iron Barron oil spill off of the Tamar river in North Tasmania. One important potential oil spill response is dispersion, but little information exists on the toxicity of dispersants and dispersed oil to Australian marine species. This research was undertaken to assess the acute toxicity of Corexit 9527 (a widely used dispersant), water accommodated fractions of Bass Strait crude oil and dispersed Bass Strait crude oil, to the saltwater amphipod, Allorchestes compressa under semi-static conditions. Acute 96 h LC50`s were determined for each toxicant as well as for the reference toxicants sodium dodecyl sulfate (SDS) and zinc sulfate. Sublethal bioassays were undertaken for the same 3 toxicants utilizing the marines and snail Polinices conicus as the test species. No-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) were determined using ANOVA while EC50`s and EC0`s were calculated using regression analysis. Mean acute 96 h LC50 (S.E.) values for A. compressa exposed to SDS and zinc sulfate were 3.6 mg/l (0.28) and 41.6 mg/l (9.01) respectively. EC50 (S.E.) concentrations for P. conicus exposed to SDS and zinc sulfate for 30 minutes were 44.7 mg/l and 246 mg/l respectively using burying behavior as an endpoint. These sublethal EC50`s were reduced to 20.7 mg/l for SDS and 23.5 mg/l for zinc sulfate following 24 hours of exposure.

  5. Toxicities of oils, dispersants and dispersed oils to algae and aquatic plants: review and database value to resource sustainability

    EPA Science Inventory

    Published toxicity results are reviewed for oils, dispersants and dispersed oils and aquatic plants. The historical phytotoxicity database consists largely of results from a patchwork of research conducted after oil spills to marine waters. Toxicity information is available for ...

  6. Using dispersants after oil spills: impacts on the composition and activity of microbial communities.

    PubMed

    Kleindienst, Sara; Paul, John H; Joye, Samantha B

    2015-06-01

    Dispersants are globally and routinely applied as an emergency response to oil spills in marine ecosystems with the goal of chemically enhancing the dissolution of oil into water, which is assumed to stimulate microbially mediated oil biodegradation. However, little is known about how dispersants affect the composition of microbial communities or their biodegradation activities. The published findings are controversial, probably owing to variations in laboratory methods, the selected model organisms and the chemistry of different dispersant-oil mixtures. Here, we argue that an in-depth assessment of the impacts of dispersants on microorganisms is needed to evaluate the planning and use of dispersants during future responses to oil spills. PMID:25944491

  7. Chemical dispersant potentiates crude oil impacts on growth, reproduction, and gene expression in Caenorhabditis elegans.

    PubMed

    Zhang, Yanqiong; Chen, Dongliang; Ennis, Adrien C; Polli, Joseph R; Xiao, Peng; Zhang, Baohong; Stellwag, Edmund J; Overton, Anthony; Pan, Xiaoping

    2013-02-01

    The economic, environmental, and human health impacts of the deepwater horizon (DWH) oil spill have been of significant concern in the general public and among scientists. This study employs parallel experiments to test the effects of crude oil from the DWH oil well, chemical dispersant Corexit 9500A, and dispersant-oil mixture on growth and reproduction in the model organism Caenorhabditis elegans. Both the crude oil and the dispersant significantly inhibited the reproduction of C. elegans. Dose-dependent inhibitions of hatched larvae production were observed in worms exposed to both crude oil and dispersant. Importantly, the chemical dispersant Corexit 9500A potentiated crude oil effects; dispersant-oil mixture induced more significant effects than oil or dispersant-alone exposures. While oil-alone exposure and dispersant-alone exposure have none to moderate inhibitory effects on hatched larvae production, respectively, the mixture of dispersant and oil induced much more significant inhibition of offspring production. The production of hatched larvae was almost completely inhibited by several high concentrations of the dispersant-oil mixture. This suggests a sensitive bioassay for future investigation of oil/dispersant impacts on organisms. We also investigated the effects of crude oil/dispersant exposure at the molecular level by measuring the expressions of 31 functional genes. Results showed that the dispersant and the dispersant-oil mixture induced aberrant expressions of 12 protein-coding genes (cat-4, trxr-2, sdhb-1, lev-8, lin-39, unc-115, prdx-3, sod-1, acr-16, ric-3, unc-68, and acr-8). These 12 genes are associated with a variety of biological processes, including egg-laying, oxidative stress, muscle contraction, and neurological functions. In summary, the toxicity potentiating effect of chemical dispersant must be taken into consideration in future crude oil cleanup applications. PMID:22990136

  8. CHARACTERISTICS OF SPILLED OILS, FUELS, AND PETROLEUM PRODUCTS: 3A. SIMULATION OF OIL SPILLS AND DISPERSANTS UNDER CONDITIONS OF UNCERTAINTY

    EPA Science Inventory

    At the request of the US EPA Oil Program Center, ERD is developing an oil spill model that focuses on fate and transport of oil components under various response scenarios. This model includes various simulation options, including the use of chemical dispersing agents on oil sli...

  9. EPA's New Oil and Dispersant Testing Program

    EPA Science Inventory

    The U.S. EPA has initiated a new component of its oil spills research program to develop baseline data on the ecotoxicity of selected petroleum products and toxicity and efficacy of dispersant agents. Two diluted bitumens (dilbits) from the Alberta Tar Sands are currently being t...

  10. Dispersion Of Crude Oil And Petroleum Products In Freshwater

    EPA Science Inventory

    The objective of this research was to investigate the relationship between dispersion effectiveness in freshwater and the surfactant composition for fresh and weathered crude oil. Although limited research on the chemical dispersion of crude oil and petroleum products in freshwat...

  11. USE OF CHEMICAL DISPERSANTS FOR MARINE OIL SPILLS

    EPA Science Inventory

    Chemical dispersants are one of the tools available to oil spill response personnel to control the spread of an oil slick. The manual presents information from the literature relative to dispersant effectiveness, toxicity and other environmental factors, regulatory and administra...

  12. USE OF CHEMICAL DISPERSANTS FOR MARINE OIL SPILLS

    EPA Science Inventory

    Chemical dispersants are one of the tools available to oil spill response personnel to control the spread of an oil slick. his manual presents information from the literature relative to dispersant effectiveness, toxicity and other environmental factors, regulatory and administra...

  13. DISPERSANT EFFECTIVENESS ON THREE OILS UNDER VARIOUS SIMULATED ENVIRONMENTAL CONDITIONS

    EPA Science Inventory

    The complexity of chemical and physical interactions between spilled oils, dispersants and the sea, necessitates an empirical approach for describing the interaction between the dispersant and oil slick which may provide a guide to dispersant effects on oil slicks. Recently, US ...

  14. Comparative Toxicity of Eight Oil Dispersants, Louisiana Sweet Crude Oil (LSC) and Chemically Dispersed LSC to Two Aquatic Test Species

    EPA Science Inventory

    This study describes the acute toxicity of eight commercial oil dispersants, Louisiana sweet crude oil (LSC), and chemically dispersed LSC. The approach utilized consistent test methodologies within a single laboratory in assessing the relative acute toxicity of the eight dispers...

  15. DISPERSANT EFFECTIVENESS ON OIL SPILLS - IMPACT OF ENVIRONMENTAL FACTORS

    EPA Science Inventory

    When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In...

  16. Effects of oil and oil dispersant on an enclosed marine ecosystem

    SciTech Connect

    Lindin, O.; Rosemarin, A.; Lindskog, A.; Hoeglund, C.; Johansson, S.

    1987-04-01

    The effects of a North Sea oil with and without the addition of an oil spill dispersant were studied in a model of the littoral ecosystem of the Baltic Sea. Measured ecosystem parameters included abundance of heterotrophic bacteria, periphyton and phytoplankton photosynthesis, growth of bladderwrack, zooplankton abundance and diversity, physiological responses of certain crustaceans and molluscs, and growth of blue mussels. In addition, net photosynthesis and respiration of the ecosystem were studied. Concentrations of oil in water and blue mussels were monitored. The results of the experiments showed that almost all the measured parameters were affected, although several of the results indicated a stronger response to oil alone than to oil plus dispersant. On the basis of the results of this experiment, it may be concluded that the use of oil dispersants on diverse shallow water communities may produce greater acute effects than if a dispersant is not used. The long-term effects, however, may prove to be less severe than the dispersion of oil by natural processes. 40 references, 10 figures, 2 tables.

  17. Fate of dispersants associated with the deepwater horizon oil spill.

    PubMed

    Kujawinski, Elizabeth B; Kido Soule, Melissa C; Valentine, David L; Boysen, Angela K; Longnecker, Krista; Redmond, Molly C

    2011-02-15

    Response actions to the Deepwater Horizon oil spill included the injection of ∼771,000 gallons (2,900,000 L) of chemical dispersant into the flow of oil near the seafloor. Prior to this incident, no deepwater applications of dispersant had been conducted, and thus no data exist on the environmental fate of dispersants in deepwater. We used ultrahigh resolution mass spectrometry and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to identify and quantify one key ingredient of the dispersant, the anionic surfactant DOSS (dioctyl sodium sulfosuccinate), in the Gulf of Mexico deepwater during active flow and again after flow had ceased. Here we show that DOSS was sequestered in deepwater hydrocarbon plumes at 1000-1200 m water depth and did not intermingle with surface dispersant applications. Further, its concentration distribution was consistent with conservative transport and dilution at depth and it persisted up to 300 km from the well, 64 days after deepwater dispersant applications ceased. We conclude that DOSS was selectively associated with the oil and gas phases in the deepwater plume, yet underwent negligible, or slow, rates of biodegradation in the affected waters. These results provide important constraints on accurate modeling of the deepwater plume and critical geochemical contexts for future toxicological studies. PMID:21265576

  18. Modeling of dispersive liquid-liquid microextraction for determination of essential oil from Borago officinalis L. by using combination of artificial neural network and genetic algorithm method.

    PubMed

    Khajeh, Mostafa; Moghaddam, Zahra Safaei; Bohlooli, Mousa; Khajeh, Ahmad

    2015-01-01

    Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography was applied for the extraction and determination of essential oil constituents of the Borago officinalis L. In this study, an experimental data-based artificial neural network (ANN) model was constructed to describe the performance of DLLME method for various operating conditions. The volume of extraction and dispersive solvents, extraction time and salt effect were the input variables of this process, whereas the extraction efficiency was the output. The ANN method was found to be capable of modeling this procedure accurately. The overall agreement between the experimental data and ANN predictions was satisfactory showing a determination coefficient of 0.982. The optimum operating condition was then determined by the genetic algorithm method. The optimal conditions were 248 µL volume of extraction solvent, 260 µL volume of dispersive solvent, 2.5 min extraction time and 0.16 mol L(-1) of salt. The limit of detection and linear dynamic range were 0.15-24.0 and 1.2-1,800 ng mL(-1), respectively. The main components of the essential oil were δ-cadinene (31.02%), carvacrol (24.91%), α-pinene (20.89%) and α-cadinol (16.47%). PMID:26045584

  19. Effects of Crude Oil, Dispersant, and Oil-Dispersant Mixtures on Human Fecal Microbiota in an In Vitro Culture System

    PubMed Central

    Kim, Jong Nam; Kim, Bong-Soo; Kim, Seong-Jae; Cerniglia, Carl E.

    2012-01-01

    ABSTRACT The Deepwater Horizon oil spill of 2010 raised concerns that dispersant and dispersed oil, as well as crude oil itself, could contaminate shellfish and seafood habitats with hazardous residues that had potential implications for human health and the ecosystem. However, little is known about the effects of crude oil and dispersant on the human fecal microbiota. The aim of this research was to evaluate the potential effects of Deepwater Horizon crude oil, Corexit 9500 dispersant, and their combination on human fecal microbial communities, using an in vitro culture test system. Fecal specimens from healthy adult volunteers were made into suspensions, which were then treated with oil, dispersant, or oil-dispersant mixtures under anaerobic conditions in an in vitro culture test system. Perturbations of the microbial community, compared to untreated control cultures, were assessed using denaturing gradient gel electrophoresis (DGGE), real-time PCR, and pyrosequencing methods. DGGE and pyrosequencing analysis showed that oil-dispersant mixtures reduced the diversity of fecal microbiota from all individuals. Real-time PCR results indicated that the copy numbers of 16S rRNA genes in cultures treated with dispersed oil or oil alone were significantly lower than those in control incubations. The abundance of the Bacteroidetes decreased in crude oil-treated and dispersed-oil-treated cultures, while the Proteobacteria increased in cultures treated with dispersed oil. In conclusion, the human fecal microbiota was affected differently by oil and dispersed oil, and the influence of dispersed oil was significantly greater than that of either oil or dispersant alone compared to control cultures. PMID:23093387

  20. Effects of oil and dispersant on formation of marine oil snow and transport of oil hydrocarbons.

    PubMed

    Fu, Jie; Gong, Yanyan; Zhao, Xiao; O'Reilly, S E; Zhao, Dongye

    2014-12-16

    This work explored the formation mechanism of marine oil snow (MOS) and the associated transport of oil hydrocarbons in the presence of a stereotype oil dispersant, Corexit EC9500A. Roller table experiments were carried out to simulate natural marine processes that lead to formation of marine snow. We found that both oil and the dispersant greatly promoted the formation of MOS, and MOS flocs as large as 1.6-2.1 mm (mean diameter) were developed within 3-6 days. Natural suspended solids and indigenous microorganisms play critical roles in the MOS formation. The addition of oil and the dispersant greatly enhanced the bacterial growth and extracellular polymeric substance (EPS) content, resulting in increased flocculation and formation of MOS. The dispersant not only enhanced dissolution of n-alkanes (C9-C40) from oil slicks into the aqueous phase, but facilitated sorption of more oil components onto MOS. The incorporation of oil droplets in MOS resulted in a two-way (rising and sinking) transport of the MOS particles. More lower-molecular-weight (LMW) n-alkanes (C9-C18) were partitioned in MOS than in the aqueous phase in the presence of the dispersant. The information can aid in our understanding of dispersant effects on MOS formation and oil transport following an oil spill event. PMID:25420231

  1. Is chemically dispersed oil more toxic to Atlantic cod (Gadus morhua) larvae than mechanically dispersed oil? A transcriptional evaluation

    PubMed Central

    2012-01-01

    Background The use of dispersants can be an effective way to deal with acute oil spills to limit environmental damage, however very little is known about whether chemically dispersed oil have the same toxic effect on marine organisms as mechanically dispersed oil. We exposed Atlantic cod larvae to chemically and mechanically dispersed oil for four days during the first-feeding stage of development, and collected larvae at 14 days post hatch for transcriptional analysis. A genome-wide microarray was used to screen for effects and to assess whether molecular responses to chemically and mechanically dispersed oil were similar, given the same exposure to oil (droplet distribution and concentration) with and without the addition of a chemical dispersant (Dasic NS). Results Mechanically dispersed oil induced expression changes in almost three times as many transcripts compared to chemically dispersed oil (fold change >+/−1.5). Functional analyses suggest that chemically dispersed oil affects partly different pathways than mechanically dispersed oil. By comparing the alteration in gene transcription in cod larvae exposed to the highest concentrations of either chemically or mechanically dispersed oil directly, the chemically dispersed oil affected transcription of genes involved nucleosome regulation, i.e. genes encoding proteins participating in DNA replication and chromatin formation and regulation of cell proliferation, whereas the mechanically dispersed oil most strongly affected genes encoding proteins involved in proteasome-mediated protein degradation. Cyp1a was the transcript that was most strongly affected in both exposure groups, with a 60-fold induction in the two high-exposure groups according to the RT-qPCR data, but no significant difference in transcriptional levels was observed between the two treatments. Conclusions In summary, dispersants do not appear to add to the magnitude of transcriptional responses of oil compounds but rather appear to lower or

  2. Oil, oil dispersants and related substances in the marine environment

    NASA Astrophysics Data System (ADS)

    Gunkel, W.; Gassmann, G.

    1980-03-01

    Of all substances threatening life in the seas, oil has received by far the most attention from the public, administrators, politicians and scientists. The main reasons for this are: (1) even limited amounts of oil are easily visible; (2) oil can exert obvious negative effects, e. g. extensive damage to birds and other animals, impairment of the recreational value of beaches and marinas, losses in fisheries due to tainting of catches and rejection by the public of seafood from areas known to have been recently polluted. In addition, dramatic tanker accidents are widely publicized. During the last decade tens of thousands of papers have been published about the impact of oil on the marine environment, and we are well informed about most basic facts, such as input and fate of oil, toxicity to adult organisms and recolonization. Due to considerable sophistication of analytical techniques, especially the introduction of glass-capillary gas chromatography, we are well aware that recently formed biogenic hydrocarbons by far extend the input directly due to pollution. Large gaps exist in our knowledge about sedimentation and transport of weathered oil, natural degradation rates, and the flow of hydrocarbons through the food web. Relatively little is known about the influence of oil and dispersants upon complex ecosystems. The often mentioned suspicion of increased cancer probability in humans due to seafood contaminated by hydrocarbons has not been substantiated; in fact, it seems unlikely that such an effect exists. By far the greatest uncertainty about potential oil impact concerns possible negative effects of hydrocarbons on chemical communication mechanisms between organisms. Intensive studies of behaviour scientists working with concentrations far below the toxic level are needed in fisheries biology, zoology and botany. Most cases of oil contamination known thus far have been limited in space and time; the oil has turned out to be degradable by natural processes

  3. Effects of crude oil, dispersant, and oil-dispersant mixtures on human fecal microbiota in an in vitro culture system.

    PubMed

    Kim, Jong Nam; Kim, Bong-Soo; Kim, Seong-Jae; Cerniglia, Carl E

    2012-01-01

    The Deepwater Horizon oil spill of 2010 raised concerns that dispersant and dispersed oil, as well as crude oil itself, could contaminate shellfish and seafood habitats with hazardous residues that had potential implications for human health and the ecosystem. However, little is known about the effects of crude oil and dispersant on the human fecal microbiota. The aim of this research was to evaluate the potential effects of Deepwater Horizon crude oil, Corexit 9500 dispersant, and their combination on human fecal microbial communities, using an in vitro culture test system. Fecal specimens from healthy adult volunteers were made into suspensions, which were then treated with oil, dispersant, or oil-dispersant mixtures under anaerobic conditions in an in vitro culture test system. Perturbations of the microbial community, compared to untreated control cultures, were assessed using denaturing gradient gel electrophoresis (DGGE), real-time PCR, and pyrosequencing methods. DGGE and pyrosequencing analysis showed that oil-dispersant mixtures reduced the diversity of fecal microbiota from all individuals. Real-time PCR results indicated that the copy numbers of 16S rRNA genes in cultures treated with dispersed oil or oil alone were significantly lower than those in control incubations. The abundance of the Bacteroidetes decreased in crude oil-treated and dispersed-oil-treated cultures, while the Proteobacteria increased in cultures treated with dispersed oil. In conclusion, the human fecal microbiota was affected differently by oil and dispersed oil, and the influence of dispersed oil was significantly greater than that of either oil or dispersant alone compared to control cultures. IMPORTANCE There have been concerns whether human health is adversely affected by exposure to spilled crude oil, which contains regulated carcinogens, such as polycyclic aromatic hydrocarbons. In this study, we determined the effect of BP Deepwater Horizon crude oil and oil dispersant on the

  4. Production and pipeline transport of oil-water dispersions

    SciTech Connect

    Carniani, E.; Celsi, A.; Ercolani, D.

    1997-07-01

    Oil-water dispersions are becoming increasingly important for their potential application in the economical exploitation of heavy-oil fields and as novel fuels to be utilized for gasification in industrial power plants and in small heating systems. Snamprogetti in co-operation with Agip and Eniricerche is involved in a research project, partially supported by the Holding Company ENI and Europen Union (Thermie project), for the developing of a new integrated process to produce heavy crude oil from the marginal fields located in the Adriatic Sea as oil-water dispersions. The process scheme provides the multiphase pipeline transportation of the oil in reservoir water dispersion (primary dispersion) from the platform to the onshore processing Oil Centre for oil production and for the preparation of a very stable dispersion of oil in fresh water (secondary dispersion) to be utilized for direct burning. To obtain the necessary information for the design of the production, transportation and processing systems Snamprogetti has equipped a pilot plant to perform dispersion preparations and characterizations, single phase and multiphase transportation tests. The present work provides experimental data relevant to pumping tests of primary and secondary dispersions showing a stable flow configuration for the secondary and a tendency to stratification for the primary in certain flow conditions. During multiphase pumping tests of primary dispersions a markedly non-newtonian behavior has been observed when strong segregation phenomena occur. A comparison with results obtained by one-phase and multiphase flow programs is also presented.

  5. BIODEGRADABILITY OF DISPERSED CRUDE OIL AT TWO DIFFERENT TEMPERATURES

    EPA Science Inventory

    Laboratory experiments were initiated to study the biodegradability of oil after dispersants were applied. Two experiments were conducted, one at 20 oC and the other at 5 oC. In both experiments, only the dispersed oil fraction was investigated. Each exper...

  6. Modeling volcanic ash dispersal

    ScienceCinema

    None

    2011-10-06

    Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

  7. Modeling volcanic ash dispersal

    SciTech Connect

    2010-10-22

    Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

  8. CHARACTERISTICS OF SPILLED OILS, FUELS, AND PETROLEUM PRODUCTS: 2A. DISPERSANT EFFECTIVENESS DATA FOR A SUITE OF ENVIRONMENTAL CONDITIONS - THE EFFECTS OF TEMPERATURE, VOLATILIZATION, AND ENERGY

    EPA Science Inventory

    Chemical dispersants are used in oil spill response operations to enhance the dispersion of oil slicks at sea as small oil droplets in the water column. To assess the impacts of dispersant usage on oil spills, US EPA is developing a simulation model called the EPA Research Object...

  9. OIL SPILL DISPERSANTS: MECHANISMS OF ACTION AND LABORATORY TESTS

    EPA Science Inventory

    Discussions are presented for (1) the mechanism of action of chemical dispersants for oil spills, (2) factors affecting performance of dispersants and its measurement, (3) some common laboratory methods that have been used to test dispersant performance, (4) a brief summary of di...

  10. Toxic effects of oil and dispersant on marine microalgae.

    PubMed

    Garr, Amber L; Laramore, Susan; Krebs, William

    2014-12-01

    To better understand the potential impacts of the deepwater horizon oil spill on lower trophic level food sources, a series of toxicological laboratory experiments were conducted with two microalgae species. The acute toxicity of oil (tar mat and MC252 crude oil), dispersant (Corexit 9500A), and dispersed oil on growth inhibition (IC50) and motility of Isochrysis galbana and Chaetoceros sp. were determined. There was no impact on cell division (growth) for microalgae exposed to both oil types and mean motility of I. galbana never dropped below 79 %. However, the addition of dispersant inhibited cell division and motility within 24 h, with Chaetoceros sp. being more susceptible to sublethal effects than I. galbana. These results highlight microalgae sensitivity to the use of dispersants in bioremediation processes, which may be a concern for long-term impacts on fisheries recruitment. PMID:25283369

  11. Tidal area dispersant project: Fate of dispersed and undispersed oil in two nearshore test spills

    SciTech Connect

    Page, D.S.; Foster, J.C.; Gerber, R.P.; Gilfillan, E.S.; Hanson, S.A.; Hotham, J.R.; Vallas, D.

    1982-10-01

    In 1981, an oil spill field experiment was done in Maine to assess the effects to the benthos of dispersant used in nearshore oil spills. Three test plots, each 60 by 100 m, were set up, each with an upper and a lower intertidal sampling area. There were also five subtidal sampling stations in water depths from 5 to 20 m. One plot was exposed to 945 L (250 gal) of Murban crude oil released on an ebbing tide withincontainment booms and cleaned up by conventional mechanical methods 24 h later. A second plot was exposed to 945 L of Murban crude oil premixed with 94 L (25 gal)of a widely available self-mix nonionic dispersant. The dispersant-treated oil was discharged over a 2-h period around high water slack tide. Dispersed oil in water reaching the bottom had lost most of the hydrocarbons more volatile than n-C/sub 17/ compared with dispersed oil in water sampled at the same time near the surface. Petroleum retention by intertidal sediments and bivalves measured one week postspill was less in areas exposed to dispersed oil than in areas exposed to untreated oil.

  12. A protocol for assessing the effectiveness of oil spill dispersants in stimulating the biodegradation of oil.

    PubMed

    Prince, Roger C; Butler, Josh D

    2014-01-01

    Dispersants are important tools in oil spill response. Taking advantage of the energy in even small waves, they disperse floating oil slicks into tiny droplets (<70 μm) that entrain in the water column and drift apart so that they do not re-agglomerate to re-form a floating slick. The dramatically increased surface area allows microbial access to much more of the oil, and diffusion and dilution lead to oil concentrations where natural background levels of biologically available oxygen, nitrogen, and phosphorus are sufficient for microbial growth and oil consumption. Dispersants are only used on substantial spills in relatively deep water (usually >10 m), conditions that are impossible to replicate in the laboratory. To date, laboratory experiments aimed at following the biodegradation of dispersed oil usually show only minimal stimulation of the rate of biodegradation, but principally because the oil in these experiments disperses fairly effectively without dispersant. What is needed is a test protocol that allows comparison between an untreated slick that remains on the water surface during the entire biodegradation study and dispersant-treated oil that remains in the water column as small dispersed oil droplets. We show here that when this is accomplished, the rate of biodegradation is dramatically stimulated by an effective dispersant, Corexit 9500. Further development of this approach might result in a useful tool for comparing the full benefits of different dispersants. PMID:23943003

  13. Protein Formulations for Emulsions and Solid-in-Oil Dispersions.

    PubMed

    Martins, Madalena; Loureiro, Ana; Azoia, Nuno G; Silva, Carla; Cavaco-Paulo, Artur

    2016-06-01

    Needs from medical and cosmetic areas have led to the design of novel nanosized emulsions and solid-in-oil dispersions of proteins. Here, we describe the production of those emulsions and dispersions using high-energy methodologies such as high-pressure homogenization or ultrasound. Recent work has resulted in new mechanistic insights related to the formation of protein emulsions and dispersions. The production method and composition of these formulations can determine major parameters such as size, stability, and functionality, and therefore their final application. Aqueous nanoemulsions of proteins can be used for drug delivery, while solid-in-oil dispersions are often used in transdermal applications. PMID:26996614

  14. Uranium Dispersion & Dosimetry Model.

    SciTech Connect

    MICHAEL,; MOMENI, H.

    2002-03-22

    The Uranium Dispersion and Dosimetry (UDAD) program provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility such as a uranium mine or mill. Only transport through the air is considered. Exposure results from inhalation, external irradiation from airborne and ground-deposited activity, and ingestion of foodstuffs. Individual dose commitments, population dose commitments, and environmental dose commitments are computed. The program was developed for application to uranium mining and milling; however, it may be applied to dispersion of any other pollutant.

  15. Uranium Dispersion & Dosimetry Model.

    Energy Science and Technology Software Center (ESTSC)

    2002-03-22

    The Uranium Dispersion and Dosimetry (UDAD) program provides estimates of potential radiation exposure to individuals and to the general population in the vicinity of a uranium processing facility such as a uranium mine or mill. Only transport through the air is considered. Exposure results from inhalation, external irradiation from airborne and ground-deposited activity, and ingestion of foodstuffs. Individual dose commitments, population dose commitments, and environmental dose commitments are computed. The program was developed for applicationmore » to uranium mining and milling; however, it may be applied to dispersion of any other pollutant.« less

  16. Dispersed oil disrupts microbial pathways in pelagic food webs.

    PubMed

    Ortmann, Alice C; Anders, Jennifer; Shelton, Naomi; Gong, Limin; Moss, Anthony G; Condon, Robert H

    2012-01-01

    Most of the studies of microbial processes in response to the Deepwater Horizon oil spill focused on the deep water plume, and not on the surface communities. The effects of the crude oil and the application of dispersants on the coastal microbial food web in the northern Gulf of Mexico have not been well characterized even though these regions support much of the fisheries production in the Gulf. A mesocosm experiment was carried out to determine how the microbial community off the coast of Alabama may have responded to the influx of surface oil and dispersants. While the addition of glucose or oil alone resulted in an increase in the biomass of ciliates, suggesting transfer of carbon to higher trophic levels was likely; a different effect was seen in the presence of dispersant. The addition of dispersant or dispersed oil resulted in an increase in the biomass of heterotrophic prokaryotes, but a significant inhibition of ciliates, suggesting a reduction in grazing and decrease in transfer of carbon to higher trophic levels. Similar patterns were observed in two separate experiments with different starting nutrient regimes and microbial communities suggesting that the addition of dispersant and dispersed oil to the northern Gulf of Mexico waters in 2010 may have reduced the flow of carbon to higher trophic levels, leading to a decrease in the production of zooplankton and fish on the Alabama shelf. PMID:22860136

  17. DEVELOPING METHODS FOR ANALYZING OIL DISPERSANTS IN SEAWATER

    EPA Science Inventory

    An analytical method was sought for determining the concentrations of dispersants in seawater contaminated with oil in both field and laboratory situations. Methods of analysis for surfactants found in the literature included spectrophotometry, gas chromatography (GC), thin-layer...

  18. Electrical properties of dispersions of graphene in mineral oil

    SciTech Connect

    Monteiro, O. R.

    2014-02-03

    Dispersions of graphene in mineral oil have been prepared and electrical conductivity and permittivity have been measured. The direct current (DC) conductivity of the dispersions depends on the surface characteristics of the graphene platelets and followed a percolation model with a percolation threshold ranging from 0.05 to 0.1 wt. %. The difference in DC conductivities can be attributed to different states of aggregation of the graphene platelets and to the inter-particle electron transfer, which is affected by the surface radicals. The frequency-dependent conductivity (σ(ω)) and permittivity (ε(ω)) were also measured. The conductivity of dispersions with particle contents much greater than the percolation threshold remains constant and equal to the DC conductivity at low frequencies ω with and followed a power-law σ(ω)∝ ω{sup s} dependence at very high frequencies with s≈0.9. For dispersions with graphene concentration near the percolation threshold, a third regime was displayed at intermediate frequencies indicative of interfacial polarization consistent with Maxwell-Wagner effect typically observed in mixtures of two (or more) phases with very distinct electrical and dielectric properties.

  19. Overview of the Toxicity of the Oil Dispersant Corexit++

    EPA Science Inventory

    The anionic surfactant dioctyl sodium sulfosuccinate (DOSS) is in the oil dispersant Corexit 9500A, which was used in the Deepwater Horizon Oil Spill. Analysis of water from the area of Deepwater Horizon showed that DOSS biodegraded little or at a slow rate several months after a...

  20. The role of dispersants' dynamic interfacial tension in effective crude oil spill dispersion.

    PubMed

    Riehm, David A; McCormick, Alon V

    2014-07-15

    The dispersion effectiveness of dispersants containing Tween 80, Span 80, and dioctyl sodium sulfosuccinate (DOSS) was characterized using a modified Swirling Flask test, and was correlated with both initial and dynamic interfacial tension produced by those dispersants at an oil-water interface. Compositional trends in effectiveness were shown to be governed by: (1) initial oil-water interfacial tension observed upon dispersant-oil-saltwater contact; (2) rate of increase (or decrease) from the initial interfacial tension as DOSS was rapidly lost to the aqueous phase; and (3) gradually slowing kinetics of dispersant adsorption to the oil-water interface as Span 80 concentration was increased, which ultimately diminished dispersion effectiveness considerably even as dynamic interfacial tension remained <10(-3) mN/m. It is proposed that this third phenomenon results not only from the hydrophobicity of Span 80, but also from the dependence of mixed Tween-Span-DOSS reverse micelles' stability in crude oil on dispersant composition. PMID:24889318

  1. EFFECTS OF CHEMICAL DISPERSANTS AND MINERAL FINES ON CRUDE OIL DISPERSION IN A WAVE TANK UNDER BREAKING WAVES

    EPA Science Inventory

    The interaction of chemical dispersants and suspended sediments with crude oil influences the fate and transport of oil spills in coastal waters. A wave tank study was conducted to investigate the effects of chemical dispersants and mineral fines on the dispersion of oil and the ...

  2. Surface roughness effects with solid lubricants dispersed in mineral oils

    NASA Technical Reports Server (NTRS)

    Cusano, C.; Goglia, P. R.; Sliney, H. E.

    1983-01-01

    The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature, indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.

  3. Slip ratio in dispersed viscous oil-water pipe flow

    SciTech Connect

    Rodriguez, Iara H.; Yamaguti, Henrique K.B.; de Castro, Marcelo S.; Rodriguez, Oscar M.H.; Da Silva, Marco J.

    2011-01-15

    In this article, dispersed flow of viscous oil and water is investigated. The experimental work was performed in a 26.2-mm-i.d. 12-m-long horizontal glass pipe using water and oil (viscosity of 100 mPa s and density of 860 kg/m{sup 3}) as test fluids. High-speed video recording and a new wire-mesh sensor based on capacitance (permittivity) measurements were used to characterize the flow. Furthermore, holdup data were obtained using quick-closing-valves technique (QCV). An interesting finding was the oil-water slip ratio greater than one for dispersed flow at high Reynolds number. Chordal phase fraction distribution diagrams and images of the holdup distribution over the pipe cross-section obtained via wire-mesh sensor indicated a significant amount of water near to the pipe wall for the three different dispersed flow patterns identified in this study: oil-in-water homogeneous dispersion (o/w H), oil-in-water non-homogeneous dispersion (o/w NH) and Dual continuous (Do/w and Dw/o). The phase slip might be explained by the existence of a water film surrounding the homogeneous mixture of oil-in-water in a hidrofilic-oilfobic pipe. (author)

  4. Optimisation of dispersion parameters of Gaussian plume model for CO₂ dispersion.

    PubMed

    Liu, Xiong; Godbole, Ajit; Lu, Cheng; Michal, Guillaume; Venton, Philip

    2015-11-01

    The carbon capture and storage (CCS) and enhanced oil recovery (EOR) projects entail the possibility of accidental release of carbon dioxide (CO2) into the atmosphere. To quantify the spread of CO2 following such release, the 'Gaussian' dispersion model is often used to estimate the resulting CO2 concentration levels in the surroundings. The Gaussian model enables quick estimates of the concentration levels. However, the traditionally recommended values of the 'dispersion parameters' in the Gaussian model may not be directly applicable to CO2 dispersion. This paper presents an optimisation technique to obtain the dispersion parameters in order to achieve a quick estimation of CO2 concentration levels in the atmosphere following CO2 blowouts. The optimised dispersion parameters enable the Gaussian model to produce quick estimates of CO2 concentration levels, precluding the necessity to set up and run much more complicated models. Computational fluid dynamics (CFD) models were employed to produce reference CO2 dispersion profiles in various atmospheric stability classes (ASC), different 'source strengths' and degrees of ground roughness. The performance of the CFD models was validated against the 'Kit Fox' field measurements, involving dispersion over a flat horizontal terrain, both with low and high roughness regions. An optimisation model employing a genetic algorithm (GA) to determine the best dispersion parameters in the Gaussian plume model was set up. Optimum values of the dispersion parameters for different ASCs that can be used in the Gaussian plume model for predicting CO2 dispersion were obtained. PMID:26374541

  5. Influence of UVB radiation on the lethal and sublethal toxicity of dispersed crude oil to planktonic copepod nauplii.

    PubMed

    Almeda, Rodrigo; Harvey, Tracy E; Connelly, Tara L; Baca, Sarah; Buskey, Edward J

    2016-06-01

    Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia tonsa, Temora turbinata and Pseudodiaptomus pelagicus. Low concentrations of dispersed crude oil (1 μL L(-1)) caused a significant reduction in survival, growth and swimming activity of copepod nauplii after 48 h of exposure. UVB radiation increased toxicity of dispersed crude oil by 1.3-3.8 times, depending on the experiment and measured variables. Ingestion of crude oil droplets may increase photoenhanced toxicity of crude oil to copepod nauplii by enhancing photosensitization. Photoenhanced sublethal toxicity was significantly higher when T. turbinata nauplii were exposed to dispersant-treated oil than crude oil alone, suggesting that chemical dispersion of crude oil may promote photoenhanced toxicity to marine zooplankton. Our results demonstrate that acute exposure to concentrations of dispersed crude oil and dispersant (Corexit 9500) commonly found in the sea after oil spills are highly toxic to copepod nauplii and that natural levels of UVB radiation substantially increase the toxicity of crude oil to these planktonic organisms. Overall, this study emphasizes the importance of considering sunlight in petroleum toxicological studies and models to better estimate the impact of crude oil spills on marine zooplankton. PMID:27003367

  6. Toxicities of Oils, Dispersants and Dispersed Oils to Aquatic Plants: Summary and Database Value to Resource Sustainability

    EPA Science Inventory

    Understanding the phytotoxicities of crude and dispersed oils is important for near-shore ecosystem management, particularly post-oil spills. One source of information is toxicity data summaries which are scattered and outdated for aquatic plants and petrochemicals. As a resu...

  7. Dynamics of Rising Dispersant Laden Oil Drops in a Quiescent Environment

    NASA Astrophysics Data System (ADS)

    Castillo-Aponte, Khalil; Mehdi, Faraz; Sheng, Jian

    2014-11-01

    We study the dynamics of rising oil drops in a quiescent fluid chamber under uniform and density stratified conditions. Digital in-line holography allows for high resolution topological measurements and tracking of drop trajectories. Statistics of rising velocities, drop shapes and sizes are compared as functions of different oil-dispersant ratios. A conceptual model of an oil drop developing appendages and its subsequent breakdown into much smaller droplets is also discussed.

  8. Surface weathering and dispersibility of MC252 crude oil.

    PubMed

    Daling, Per S; Leirvik, Frode; Almås, Inger Kjersti; Brandvik, Per Johan; Hansen, Bjørn Henrik; Lewis, Alun; Reed, Mark

    2014-10-15

    Results from a comprehensive oil weathering and dispersant effectiveness study of the MC252 crude oil have been used to predict changes in oil properties due to weathering on the sea surface and to estimate the effective "time window" for dispersant application under various sea conditions. MC252 oil is a light paraffinic crude oil, for which approximately 55 wt.% will evaporate within 3-5 days when drifting on the sea. An unstable and low-viscosity water-in-oil (w/o) emulsion are formed during the first few days at the sea surface. This allows a high degree of natural dispersion when exposed to breaking wave conditions. Under calm sea conditions, a more stable and light-brown/orange colored water-in-oil (w/o) emulsion may start to form after several days, and viscosities of 10,000-15,000 mPa s can be achieved after 1-2 weeks. The "time window" for effective use of dispersants was estimated to be more than 1 week weathering at sea. PMID:25152185

  9. Effect of oil and oil dispersant mixtures on the basal metabolic rate of ducks

    SciTech Connect

    Lambert, G.; Peakall, D.B.; Philogene, B.J.R.; Engelhardt, F.R.

    1982-11-01

    Wild strain adult mallards (Anas platrhynchos) were exposed to either Prudhoe Bay crude oil, Corexit 9527 dispersant or the crude oil + dispersant. Results show that the degree of oiling to which the ducks were exposed caused a modest but significant increase in the metabolic rate. Under the experimental conditions (one-hour exposure, small volume swimming tanks, measuring of metabolism after the removal of the bird from the water), the dispersant (at 30:1 ratio) does not appreciably increase the effects caused by the crude oil on the metabolic rate, although it seems to increase the damage to plumage which leads to progressive waterlogging. (JMT)

  10. Partitioning of fresh crude oil between floating, dispersed and sediment phases: Effect of exposure order to dispersant and granular materials.

    PubMed

    Boglaienko, Daria; Tansel, Berrin

    2016-06-15

    When three or more high and low energy substrates are mixed, wetting order can significantly affect the behavior of the mixture. We analyzed the phase distribution of fresh floating Louisiana crude oil into dispersed, settled and floating phases depending on the exposure sequence to Corexit 9500A (dispersant) and granular materials. In the experiments artificial sea water at salinity 34‰ was used. Limestone (2.00-0.300 mm) and quartz sand (0.300-0.075 mm) were used as the natural granular materials. Dispersant Corexit 9500A increased the amount of dispersed oil up to 33.76 ± 7.04%. Addition of granular materials after the dispersant increased dispersion of oil to 47.96 ± 1.96%. When solid particles were applied on the floating oil before the dispersant, oil was captured as oil-particle aggregates and removed from the floating layer. However, dispersant addition led to partial release of the captured oil, removing it from the aggregated form to the dispersed and floating phases. There was no visible oil aggregation with the granular materials when quartz or limestone was at the bottom of the flask before the addition of oil and dispersant. The results show that granular materials can be effective when applied from the surface for aggregating or dispersing oil. However, the granular materials in the sediments are not effective neither for aggregating nor dispersing floating oil. PMID:27019358

  11. Effects of Salinity on Oil Spill Dispersant Toxicity in Estuarine Organisms

    NASA Astrophysics Data System (ADS)

    Eckmann, C. A.

    2015-12-01

    Chemical dispersants can be a useful tool to mitigate oil spills, but the potential risks to sensitive estuarine species should be carefully considered. To improve the decision making process, more information is needed regarding the effects of oil spill dispersants on the health of coastal ecosystems under variable environmental conditions such as salinity. The two oil dispersants used in this study were Corexit ® 9500 and Finasol ® OSR 52. Corexit ® 9500 was the primary dispersant used during the 2010 Deepwater Horizon oil spill event, while Finasol® OSR 52 is another dispersant approved for oil spill response in the U.S., yet considerably less is known regarding its toxicity to estuarine species. The grass shrimp, Palaemonetes pugio, was used as a model estuarine species. It is a euryhaline species that tolerates salinities from brackish to full strength seawater. Adult and larval life stages were tested with each dispersant at three salinities, 5ppt, 20ppt, and 30ppt. Median acute lethal toxicity thresholds were calculated. Lipid peroxidation assays were conducted on surviving shrimp to investigate sublethal effects. The toxicity of both dispersants was significantly influenced by salinity, with greatest toxicity observed at the lowest salinity tested. Larval shrimp were significantly more sensitive than adult shrimp to both dispersants, and both life stages were significantly more sensitive to Finasol than to Corexit. Furthermore, significant sublethal effects were seen at higher concentrations of both dispersants compared to the control. These data will enable environmental managers to make informed decisions regarding dispersant use in future oil spills.

  12. Lung epithelial cell death induced by oil-dispersant mixtures.

    PubMed

    Wang, He; Shi, Yongli; Major, Danielle; Yang, Zhanjun

    2012-08-01

    The dispersants used in oil spill disasters are claimed to be safe, but increased solubility of high-molecular-weight components in crude oil is of public health concern. The water-accommodated fractions (WAF) of crude oil mixed with dispersants may become airborne and cause lung epithelial damage when inhaled. This study was designed to examine the cell death and related death pathways of lung epithelial cells in response to WAF. Cultured A549 cells were treated for 2 or 24h with different concentrations of WAF. The WAF was prepared by mixing each of the dispersants (Corexit EC9527A, Corexit EC9500A and Corexit EC9580A) with crude oil for extraction with PBS. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay, lactate dehydrogenase assay, morphology and cleaved caspase 9 protein, and microtubule-associated protein 1 light chain 3 were all used to measure cell viability, necrosis, apoptosis and autophagy quantitation, respectively. Results showed that the WAF of oil-dispersant mixtures caused cell death in the lung epithelial cells, in a dose-dependent manner, with the major cellular pathways of necrosis and apoptosis involved. Autophagy also occurred in cells exposed to WAF mixtures at lower concentrations before any detectable cell death, indicating greater sensitivity to WAF exposure. The three types of cell behavior, namely necrosis, apoptosis and autophagy, may play different roles in oil spill-related respiratory disorders. PMID:22504303

  13. Experimental investigation of two oil dispersion pathways by breaking waves

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Katz, Joseph

    2014-11-01

    This experimental study focuses on generation and size distribution of airborne and subsurface oil droplets as breaking surface waves interact with a crude oil slick (MC252 surrogate). Experiments in a specialized wave tank investigate the effects of wave height and wave properties (e.g. spilling vs. plunging), as well as drastically reducing the oil-water interfacial tension by orders of magnitude by introducing dispersant (Coexist 9500-A). This dispersant is applied at varying dispersant-to-oil ratios either by premixing or surface spraying, the latter consistent with typical application. The data include high-speed visualizations of processes affecting the entrainment of subsurface oil and bubbles as well as airborne aerosols. High-speed digital holographic cinematography is employed to track the droplet trajectories, and quantify the droplet size distributions above and below the surface. Introduction of dispersants drastically reduces the size of subsurface droplets to micron and even submicron levels. Ahead of the wave, the 25 μm (our present resolution limit) to 2 mm airborne droplet trajectories are aligned with the wave direction. Behind the wave, these droplets reverse their direction, presumably due to the airflow above the wave. Supported by Gulf of Mexico Research Initiative (GoMRI).

  14. Combined effect of oil, oil products and dispersants on the blue-green algae Synechocystis aquatilis and Anabaena variabilis

    SciTech Connect

    Gapochka, L.D.; Brodskii, L.I.; Kravchenko, M.E.; Fedorov, V.D.

    1980-01-01

    The study of the combined effect of oil, oil products and dispersants on the growth of the blue-green algae Synechocystis aquatilis and Anabaena variabilis has shown that out of 12 studied oil-dispersant pairs 6 revealed a positive relationship, which provides evidence for a decrease in oil and oil products toxic effect in the presence of a dispersant. The positive interaction between oil and oil products was found. The negative oil and oil products effect on all studied indices of A. variabilis culture increases with time.

  15. Use of dispersant in mudflat oil-contaminated sediment: behavior and effects of dispersed oil on micro- and macrobenthos.

    PubMed

    Cuny, Philippe; Gilbert, Franck; Militon, Cécile; Stora, Georges; Bonin, Patricia; Michotey, Valérie; Guasco, Sophie; Duboscq, Karine; Cagnon, Christine; Jézéquel, Ronan; Cravo-Laureau, Cristiana; Duran, Robert

    2015-10-01

    The present study aimed to examine whether the use of dispersant would be suitable for favoring the hydrocarbon degradation in coastal marine sediments without impacting negatively micro- and macrobenthic organisms. Mudflat sediments, maintained during 286 days in mesocosms designed to simulate natural conditions, were contaminated or not with Ural blend crude oil (REBCO) and treated or not with third-generation dispersant (Finasol OSR52). While the dispersant did not lead to an increase of hydrocarbon biodegradation, its use enables an attenuation of more than 55 % of the sediment concentration of total petroleum hydrocarbons (TPH). Canonical correspondence analysis (CCA) correlating T-RFLP patterns with the hydrocarbon content and bacterial abundance indicated weak differences between the different treatments except for the mesocosm treated with oil and dispersant for which a higher bacterial biomass was observed. The use of the dispersant did not significantly decrease the macrobenthic species richness or macroorganisms' densities in uncontaminated or contaminated conditions. However, even if the structure of the macrobenthic communities was not affected, when used in combination with oil, biological sediment reworking coefficient was negatively impacted. Although the use of the dispersant may be worth considering in order to accelerate the attenuation of hydrocarbon-contaminated mudflat sediments, long-term effects on functional aspects of the benthic system such as bioturbation and bacterial activity should be carefully studied before. PMID:26062462

  16. Solvent disperser for removing oil from sponge core

    SciTech Connect

    Di Foggio, R.

    1988-09-20

    This patent describes method for dispersing solvent for use in determining the oil saturation of an earth formation by means of sponge coring, comprising: (a) receiving solvent dripping downwardly, and (b) conducting the received solvent by means of capillary action to an application zone located and dimensioned for passing such solvent to the sponge in a sponge core barrel.

  17. Application of fluorescence and PARAFAC to assess vertical distribution of subsurface hydrocarbons and dispersant during the Deepwater Horizon oil spill.

    PubMed

    Mendoza, Wilson G; Riemer, Daniel D; Zika, Rod G

    2013-05-01

    We evaluated the use of excitation and emission matrix (EEM) fluorescence and parallel factorial analysis (PARAFAC) modeling techniques for monitoring crude oil components in the water column. Four of the seven derived PARAFAC loadings were associated with the Macondo crude oil components. The other three components were associated with the dispersant, an unresolved component and colored dissolved organic matter (CDOM). The fluorescence of the associated benzene and naphthalene-like components of crude oil exhibited a maximum at ∼1200 m. The maximum fluorescence of the component associated with the dispersant (i.e., Corexit EC9500A) was observed at the same depth. The plume observed at this depth was attributed to the dispersed crude oil from the Deepwater Horizon oil spill. Results demonstrate the application of EEM and PARAFAC to simultaneously monitor selected PAH, dispersant-containing and humic-like fluorescence components in the oil spill region in the Gulf of Mexico. PMID:23546220

  18. MODELING METHODOLOGIES FOR OIL SPILLS

    EPA Science Inventory

    Oil spilled into aquatic environments is subject to a number of fates, including natural dispersion, emulsification and weathering. An oil slick moves due to the inherent spreading of the oil, currents, winds and waves. All of these processes influence the impacts of the oil on...

  19. Optical Contrast of Oil Dispersed in Seawater Under Windy Conditions

    NASA Astrophysics Data System (ADS)

    Otremba, Z.; Zielinski, O.; Hu, C.

    2013-07-01

    Oil pollution of natural waters represents a serious threat for aquatic ecosystems, and the assessment of the degree of pollution requiresmeasurement strategies including remote sensing and modeling. While surface oil pollution is relatively easy to detect with radar or opticalremote sensing, underwater oil emulsions can only be detected using visible light as an information carrier. Here the Michelson contrast ofsea area polluted by an oil-in-water emulsion under various wind conditions is simulated through Monte-Carlo modeling. The results showthe premise for optimal direction of observations in which the possibility of detecting the emulsified oil is maximized.

  20. Integrated Urban Dispersion Modeling Capability

    SciTech Connect

    Kosovic, B; Chan, S T

    2003-11-03

    Numerical simulations represent a unique predictive tool for developing a detailed understanding of three-dimensional flow fields and associated concentration distributions from releases in complex urban settings (Britter and Hanna 2003). The accurate and timely prediction of the atmospheric dispersion of hazardous materials in densely populated urban areas is a critical homeland and national security need for emergency preparedness, risk assessment, and vulnerability studies. The main challenges in high-fidelity numerical modeling of urban dispersion are the accurate prediction of peak concentrations, spatial extent and temporal evolution of harmful levels of hazardous materials, and the incorporation of detailed structural geometries. Current computational tools do not include all the necessary elements to accurately represent hazardous release events in complex urban settings embedded in high-resolution terrain. Nor do they possess the computational efficiency required for many emergency response and event reconstruction applications. We are developing a new integrated urban dispersion modeling capability, able to efficiently predict dispersion in diverse urban environments for a wide range of atmospheric conditions, temporal and spatial scales, and release event scenarios. This new computational fluid dynamics capability includes adaptive mesh refinement and it can simultaneously resolve individual buildings and high-resolution terrain (including important vegetative and land-use features), treat complex building and structural geometries (e.g., stadiums, arenas, subways, airplane interiors), and cope with the full range of atmospheric conditions (e.g. stability). We are developing approaches for seamless coupling with mesoscale numerical weather prediction models to provide realistic forcing of the urban-scale model, which is critical to its performance in real-world conditions.

  1. NEUROTOXICITY FOLLOWING ACUTE INHALATION EXPOSURE TO THE OIL DISPERSANT COREXIT EC9500A

    PubMed Central

    Sriram, Krishnan; Lin, Gary X.; Jefferson, Amy M.; Goldsmith, William T.; Jackson, Mark; McKinney, Walter; Frazer, David G.; Robinson, Victor A.; Castranova, Vincent

    2015-01-01

    Consequent to the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, there is an emergent concern about the short- and long-term adverse health effects of exposure to crude oil, weathered-oil products, and oil dispersants among the workforce employed to contain and clean up the spill. Oil dispersants typically comprise of a mixture of solvents and surfactants that break down floating oil to micrometer-sized droplets within the water column, thus preventing it from reaching the shorelines. As dispersants are generally sprayed from the air, workers are at risk for exposure primarily via inhalation. Such inhaled fractions might potentially permeate or translocate to the brain via olfactory or systemic circulation, producing central nervous system (CNS) abnormalities. To determine whether oil dispersants pose a neurological risk, male Sprague-Dawley rats were exposed by whole-body inhalation exposure to a model oil dispersant, COREXIT EC9500A (CE; approximately 27 mg/m3 × 5 h/d × 1 d), and various molecular indices of neural dysfunction were evaluated in discrete brain areas, at 1 or 7 d postexposure. Exposure to CE produced partial loss of olfactory marker protein in the olfactory bulb. CE also reduced tyrosine hydroxylase protein content in the striatum. Further, CE altered the levels of various synaptic and neuronal intermediate filament proteins in specific brain areas. Reactive astrogliosis, as evidenced by increased expression of glial fibrillary acidic protein, was observed in the hippocampus and frontal cortex following exposure to CE. Collectively, these findings are suggestive of disruptions in olfactory signal transduction, axonal function, and synaptic vesicle fusion, events that potentially result in an imbalance in neurotransmitter signaling. Whether such acute molecular aberrations might persist and produce chronic neurological deficits remains to be ascertained. PMID:21916746

  2. Neurotoxicity following acute inhalation exposure to the oil dispersant COREXIT EC9500A.

    PubMed

    Sriram, Krishnan; Lin, Gary X; Jefferson, Amy M; Goldsmith, William T; Jackson, Mark; McKinney, Walter; Frazer, David G; Robinson, Victor A; Castranova, Vincent

    2011-01-01

    Consequent to the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, there is an emergent concern about the short- and long-term adverse health effects of exposure to crude oil, weathered-oil products, and oil dispersants among the workforce employed to contain and clean up the spill. Oil dispersants typically comprise of a mixture of solvents and surfactants that break down floating oil to micrometer-sized droplets within the water column, thus preventing it from reaching the shorelines. As dispersants are generally sprayed from the air, workers are at risk for exposure primarily via inhalation. Such inhaled fractions might potentially permeate or translocate to the brain via olfactory or systemic circulation, producing central nervous system (CNS) abnormalities. To determine whether oil dispersants pose a neurological risk, male Sprague-Dawley rats were exposed by whole-body inhalation exposure to a model oil dispersant, COREXIT EC9500A (CE; approximately 27 mg/m(3) × 5 h/d × 1 d), and various molecular indices of neural dysfunction were evaluated in discrete brain areas, at 1 or 7 d postexposure. Exposure to CE produced partial loss of olfactory marker protein in the olfactory bulb. CE also reduced tyrosine hydroxylase protein content in the striatum. Further, CE altered the levels of various synaptic and neuronal intermediate filament proteins in specific brain areas. Reactive astrogliosis, as evidenced by increased expression of glial fibrillary acidic protein, was observed in the hippocampus and frontal cortex following exposure to CE. Collectively, these findings are suggestive of disruptions in olfactory signal transduction, axonal function, and synaptic vesicle fusion, events that potentially result in an imbalance in neurotransmitter signaling. Whether such acute molecular aberrations might persist and produce chronic neurological deficits remains to be ascertained. PMID:21916746

  3. Evolution of the Macondo well blowout: simulating the effects of the circulation and synthetic dispersants on the subsea oil transport.

    PubMed

    Paris, Claire B; Hénaff, Matthieu Le; Aman, Zachary M; Subramaniam, Ajit; Helgers, Judith; Wang, Dong-Ping; Kourafalou, Vassiliki H; Srinivasan, Ashwanth

    2012-12-18

    During the Deepwater Horizon incident, crude oil flowed into the Gulf of Mexico from 1522 m underwater. In an effort to prevent the oil from rising to the surface, synthetic dispersants were applied at the wellhead. However, uncertainties in the formation of oil droplets and difficulties in measuring their size in the water column, complicated further assessment of the potential effect of the dispersant on the subsea-to-surface oil partition. We adapted a coupled hydrodynamic and stochastic buoyant particle-tracking model to the transport and fate of hydrocarbon fractions and simulated the far-field transport of the oil from the intrusion depth. The evaluated model represented a baseline for numerical experiments where we varied the distributions of particle sizes and thus oil mass. The experiments allowed to quantify the relative effects of chemical dispersion, vertical currents, and inertial buoyancy motion on oil rise velocities. We present a plausible model scenario, where some oil is trapped at depth through shear emulsification due to the particular conditions of the Macondo blowout. Assuming effective mixing of the synthetic dispersants at the wellhead, the model indicates that the submerged oil mass is shifted deeper, decreasing only marginally the amount of oil surfacing. In this scenario, the oil rises slowly to the surface or stays immersed. This suggests that other mechanisms may have contributed to the rapid surfacing of oil-gas mixture observed initially. The study also reveals local topographic and hydrodynamic processes that influence the oil transport in eddies and multiple layers. This numerical approach provides novel insights on oil transport mechanisms from deep blowouts and on gauging the subsea use of synthetic dispersant in mitigating coastal damage. PMID:23167517

  4. Effects of oil dispersants on photodegradation of pyrene in marine water.

    PubMed

    Gong, Yanyan; Fu, Jie; O'Reilly, S E; Zhao, Dongye

    2015-04-28

    This work investigated effects of a popular oil dispersant (Corexit EC9500A) on UV- or sunlight-mediated photodegradation of pyrene (a model polycyclic aromatic hydrocarbon) in seawater. The presence of 18 and 180mg/L of the dispersant increased the first-order photodegradation rate by 5.5% and 16.7%, respectively, and reduced or ceased pyrene volatilization. By combining individual first-order rate laws for volatilization and photodegradation, we proposed an integrated kinetic model that can adequately predict the overall dissipation of pyrene from seawater. Mechanistic studies indicated that superoxide radicals played a predominant role in pyrene photodegradation, and the dispersant enhanced formation of superoxide radicals. 1-Hydroxypyrene was the main intermediate regardless of the dispersant, suggesting that electrons were transferred from excited pyrene to oxygen. In the presence of 18mg/L of the dispersant, the photodegradation rate increased with increasing ionic strength and temperature, but decreased with increasing HA concentration, and remained independent of solution pH. The results are important in understanding roles of oil dispersants on environmental fate of persistent oil components in natural and engineered systems. PMID:25655421

  5. Bioaccumulation of petroleum hydrocarbons in fiddler crabs (Uca minax) exposed to weathered MC-252 crude oil alone and in mixture with an oil dispersant.

    PubMed

    Chase, Darcy A; Edwards, Donn S; Qin, Guangqiu; Wages, Mike R; Willming, Morgan M; Anderson, Todd A; Maul, Jonathan D

    2013-02-01

    The Deepwater Horizon accident in the Gulf of Mexico resulted in a sustained release of crude oil, and weathered oil was reported to have washed onto shorelines and marshes along the Gulf coast. One strategy to minimize effects of tarballs, slicks, and oil sheen, and subsequent risk to nearshore ecosystem resources was to use oil dispersants (primarily Corexit® 9500) at offshore surface and deepwater locations. Data have been generated reporting how Corexit® 9500 and other dispersants may alter the acute toxicity of crude oil (Louisiana sweet crude) to marine organisms. However, it remains unknown how oil dispersants may influence bioaccumulation of petroleum hydrocarbons in nearshore crustaceans. We compare bioaccumulation of petroleum hydrocarbons in fiddler crabs (Uca minax) from exposures to the water accommodated fraction (WAF) of weathered Mississippi Canyon 252 oil (~30 d post spill) and chemically-enhanced WAF when mixed with Corexit® EC9500A. Whole body total petroleum hydrocarbon (TPH) concentrations were greater than background for both treatments after 6h of exposure and reached steady state at 96 h. The modeled TPH uptake rate was greater for crabs in the oil only treatment (k(u)=2.51 mL/g/h vs. 0.76 mL/g/h). Furthermore, during the uptake phase TPH patterns in tissues varied between oil only and oil+dispersant treatments. Steady state bioaccumulation factors (BAFs) were 19.0 mL/g and 14.1 mL/g for the oil only and oil+Corexit treatments, respectively. These results suggest that the toxicokinetic mechanisms of oil may be dependent on oil dispersion (e.g., smaller droplet sizes). The results also indicate that multiple processes and functional roles of species should be considered for understanding how dispersants influence bioavailability of petroleum hydrocarbons. PMID:23268140

  6. Wave Tank Studies On Formation And Transport Of OMA From The Chemically Dispersed Oil

    EPA Science Inventory

    The interaction of chemical dispersants and suspended sediments with crude oil influences the fate and transport of oil spills in coastal waters. A wave tank study was conducted to investigate the effects of chemical dispersants and mineral fines on dispersion of oil, formation ...

  7. Dispersant use as a response to oil spills: toxicological effects on fish cardiac performance.

    PubMed

    Milinkovitch, Thomas; Thomas-Guyon, Hélène; Lefrançois, Christel; Imbert, Nathalie

    2013-04-01

    Dispersant use is a controversial technique used to respond to oil spills in nearshore areas. In order to assess the toxicity of this technique, this study evaluated the cardiac toxicological effects on juvenile golden grey mullets Liza aurata exposed for 48 h to either dispersant alone, chemically dispersed oil, mechanically dispersed oil, the water-soluble fraction of oil or a control condition. Following exposure, the positive inotropic effects of adrenaline were assessed in order to evaluate a potential impairment on the cardiac performance. The results revealed an impairment of the positive inotropic effects of adrenaline for all the contaminants (single dispersant, dispersed and undispersed oil, water-soluble fraction of oil). This suggests that: (1) cardiac performance is a valuable parameter to study the physiopathological effects of dispersed oil; (2) dispersant application is likely to impair cardiac performance. PMID:22976195

  8. The toxicity of oil and chemically dispersed oil to the seagrass Thalassia testudinum

    SciTech Connect

    Baca, B.J.; Getter, C.D.

    1982-10-01

    Turtle grass beds, a valuable natural resource, are diminishing throughout the tropics because of damage from dredging, boats, and other factors. The toxicity of chemical dispersants and crude oil to turtle grass was determined in the laboratory to assess the potential for damage from spills occurring in the field. Studies of water-soluble fractions (WSF) of crude oil in static bioassays showed that a chemical dispersant (Corexit 9527) increased the amount of total oil in water more than 50-fold. The toxicity of chemically dispersed oil was assessed by conventional (96-h 50% lethal concentration) methods in static systems, and the results were compared with toxicity measurements where the system was flushed after 12 h. Prudhoe Bay crude WSF was more toxic than dispersed oil or dispersant alone, possibly because of the large component of benzene, toluene, and C-2 benzene. The percentage of green (chlorophyllous) leaves was useful as evidence of toxicity. The importance of anatomical features such as recessed meristem and abundant leaf sheaths in protecting the growing region from waterborne pollutants was evident.

  9. Reproduction dynamics in copepods following exposure to chemically and mechanically dispersed crude oil.

    PubMed

    Hansen, Bjørn Henrik; Salaberria, Iurgi; Olsen, Anders J; Read, Kari Ella; Øverjordet, Ida Beathe; Hammer, Karen M; Altin, Dag; Nordtug, Trond

    2015-03-17

    Conflicting reports on the contribution of chemical dispersants on crude oil dispersion toxicity have been published. This can partly be ascribed to the influence of dispersants on the physical properties of the oil in different experimental conditions. In the present study the potential contribution of dispersants to the reproductive effects of dispersed crude oil in the marine copepod Calanus finmarchicus (Gunnerus) was isolated by keeping the oil concentrations and oil droplet size distributions comparable between parallel chemically dispersed (CD, dispersant:oil ratio 1:25) and mechanically dispersed oil (MD, no dispersant) exposures. Female copepods were exposed for 96 h to CD or MD in oil concentration range of 0.2-5.5 mg·L(-1) (THC, C5-C36) after which they were subjected to a 25-day recovery period where production of eggs and nauplii were compared between treatments. The two highest concentrations, both in the upper range of dispersed oil concentrations reported during spills, caused a lower initial production of eggs/nauplii for both MD and CD exposures. However, copepods exposed to mechanically dispersed oil exhibited compensatory reproduction during the last 10 days of the recovery period, reaching control level of cumulative egg and nauplii production whereas females exposed to a mixture of oil and dispersant did not. PMID:25658869

  10. Evaluation of metabolic responses of Artemia salina to oil and oil dispersant as a potential indicator of toxicant stress

    SciTech Connect

    Verriopoulos, G.; Moraitou-Apostolopoulou, M.; Xatzispirou, A.

    1986-03-01

    Oil represents an obvious hazard for the coastal environment and studies on its impact on marine organisms are necessary. Solvent based oil dispersants constitute one of the most important means for removing oil from shores. Although recently new dispersants have been developed, which are much less toxic than the first ones, dispersants still remain toxic substances. Since in the case of oil pollution treatment, oils and detergents are acting in combination, a realistic approach of laboratory studies must also include the combined action of these substances on marine organisms. Although acute toxicity studies are very useful for the determination of the range of animal tolerance, other effects causing physiological alterations may be detrimental to a population's survival. This paper concerns research on the effects of an oil, an oil dispersant and of the mixture of oil and dispersant on a physiological process, the respiration of the brine shrimp Artemia salina.

  11. Oil spill impact modeling: development and validation.

    PubMed

    French-McCay, Deborah P

    2004-10-01

    A coupled oil fate and effects model has been developed for the estimation of impacts to habitats, wildlife, and aquatic organisms resulting from acute exposure to spilled oil. The physical fates model estimates the distribution of oil (as mass and concentrations) on the water surface, on shorelines, in the water column, and in the sediments, accounting for spreading, evaporation, transport, dispersion, emulsification, entrainment, dissolution, volatilization, partitioning, sedimentation, and degradation. The biological effects model estimates exposure of biota of various behavior types to floating oil and subsurface contamination, resulting percent mortality, and sublethal effects on production (somatic growth). Impacts are summarized as areas or volumes affected, percent of populations lost, and production foregone because of a spill's effects. This paper summarizes existing information and data used to develop the model, model algorithms and assumptions, validation studies, and research needs. Simulation of the Exxon Valdez oil spill is presented as a case study and validation of the model. PMID:15511105

  12. Effect of crude oil exposure and dispersant application on meiofauna: an intertidal mesocosm experiment.

    PubMed

    Elarbaoui, Soumaya; Richard, Marion; Boufahja, Fehmi; Mahmoudi, Ezzeddine; Thomas-Guyon, Hélène

    2015-05-01

    Dispersant application is used as a response technique to minimize the environmental risk of an oil spill. In nearshore areas, dispersant application is a controversial countermeasure: environmental benefits are counteracted by the toxicity of dispersant use. The effects of the use of chemical dispersants on meiobenthic organisms and nematodes were investigated in a mesocosm experiment. A 20 day experiment was performed in four experimental sets of mesocosms. In three of them, sediments were contaminated, respectively by oil (500 mg kg(-1)), dispersed oil (oil + 5% dispersant), and dispersant alone, whereas in the last set sediments were kept undisturbed and used as a reference (Re). Our results showed that the meiobenthic response to oil contamination was rapid, for copepods and nematodes. One-way ANOVA showed a significant decrease of the abundance of copepods. In the case of nematodes, univariate and multivariate analyses indicated a clear decrease of the abundance of the species after only 20 days of pollutant exposure and thus reducing Shannon-Wiener diversity and Pielou's evenness. In contrast, Sphaerolaimus gracilis and Sabateria sp. became more frequent within disturbed assemblages and appeared to be resistant and/or opportunistic species in the presence of these kinds of toxicants. Moreover, responses of copepods and nematodes to the treatment seemed to be the same irrespective of whether only oil or oil + dispersant was performed. The main toxicities of dispersed oil come not from the "composition of a newly formed oil and oil spill dispersant mixture" but from the "quantities of increased dispersed oil droplets". PMID:25948118

  13. Surface dynamics of crude and weathered oil in the presence of dispersants: Laboratory experiment and numerical simulation

    NASA Astrophysics Data System (ADS)

    Soloviev, Alexander V.; Haus, Brian. K.; McGauley, Michael G.; Dean, Cayla W.; Ortiz-Suslow, David G.; Laxague, Nathan J. M.; Özgökmen, Tamay M.

    2016-05-01

    Marine oil spills can have dire consequences for the environment. Research on their dynamics is important for the well-being of coastal communities and their economies. Propagation of oil spills is a very complex physical-chemical process. As seen during the Deepwater Horizon event in the Gulf of Mexico during 2010, one of the critical problems remaining for prediction of oil transport and dispersion in the marine environment is the small-scale structure and dynamics of surface oil spills. The laboratory experiments conducted in this work were focused on understanding the differences between the dynamics of crude and weathered oil spills and the effect of dispersants. After deposition on the still water surface, a drop of crude oil quickly spread into a thin slick; while at the same time, a drop of machine (proxy for weathered) oil did not show significant evolution. Subsequent application of dispersant to the crude oil slick resulted in a quick contraction or fragmentation of the slick into narrow wedges and tiny drops. Notably, the slick of machine oil did not show significant change in size or topology after spraying dispersant. An advanced multi-phase, volume of fluid computational fluid dynamics model, incorporating capillary forces, was able to explain some of the features observed in the laboratory experiment. As a result of the laboratory and modeling experiments, the new interpretation of the effect of dispersant on the oil dispersion process including capillary effects has been proposed, which is expected to lead to improved oil spill models and response strategies.

  14. Evaluating crude oil chemical dispersion efficacy in a flow-through wave tank under regular non-breaking wave and breaking wave conditions.

    PubMed

    Li, Zhengkai; Lee, Kenneth; King, Thomas; Boufadel, Michel C; Venosa, Albert D

    2009-05-01

    Testing dispersant effectiveness under conditions similar to that of the open environment is required for improvements in operational procedures and the formulation of regulatory guidelines. To this end, a novel wave tank facility was fabricated to study the dispersion of crude oil under regular non-breaking and irregular breaking wave conditions. This wave tank facility was designed for operation in a flow-through mode to simulate both wave- and current-driven hydrodynamic conditions. We report here an evaluation of the effectiveness of chemical dispersants (Corexit EC9500A and SPC 1000) on two crude oils (Medium South American [MESA] and Alaska North Slope [ANS]) under two different wave conditions (regular non-breaking and plunging breaking waves) in this wave tank. The dispersant effectiveness was assessed by measuring the water column oil concentration and dispersed oil droplet size distribution. In the absence of dispersants, nearly 8-19% of the test crude oils were dispersed and diluted under regular wave and breaking wave conditions. In the presence of dispersants, about 21-36% of the crude oils were dispersed and diluted under regular waves, and 42-62% under breaking waves. Consistently, physical dispersion under regular waves produced large oil droplets (volumetric mean diameter or VMD > or = 300 microm), whereas chemical dispersion under breaking waves created small droplets (VMD < or = 50 microm). The data can provide useful information for developing better operational guidelines for dispersant use and improved predictive models on dispersant effectiveness in the field. PMID:19157465

  15. MEDSLIK oil spill model recent developments

    NASA Astrophysics Data System (ADS)

    Lardner, Robin; Zodiatis, George

    2016-04-01

    MEDSLIK oil spill model recent developments Robin Lardner and George Zodiatis Oceanography Center, University of Cyprus, 1678 Nicosia, Cyprus MEDSLIK is a well established 3D oil spill model that predicts the transport, fate and weathering of oil spills and is used by several response agencies and institutions around the Mediterranean, the Black seas and worldwide. MEDSLIK has been used operationally for real oil spill accidents and for preparedness in contingency planning within the framework of pilot projects with REMPEC-Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea and EMSA-European Maritime Safety Agency. MEDSLIK has been implemented in many EU funded projects regarding oil spill predictions using the operational ocean forecasts, as for example the ECOOP, NEREIDs, RAOP-Med, EMODNET MedSea Check Point. Within the frame of MEDESS4MS project, MEDSLIK is at the heart of the MEDESS4MS multi model oil spill prediction system. The MEDSLIK oil spill model contains among other, the following features: a built-in database with 240 different oil types characteristics, assimilation of oil slick observations from in-situ or aerial, to correct the predictions, virtual deployment of oil booms and/or oil skimmers/dispersants, continuous or instantaneous oil spills from moving or drifting ships whose slicks merge can be modelled together, multiple oil spill predictions from different locations, backward simulations for tracking the source of oil spill pollution, integration with AIS data upon the availability of AIS data, sub-surface oil spills at any given water depth, coupling with SAR satellite data. The MEDSLIK can be used for operational intervention for any user-selected region in the world if the appropriate coastline, bathymetry and meteo-ocean forecast files are provided. MEDSLIK oil spill model has been extensively validated in the Mediterranean Sea, both in real oil spill incidents (i.e. during the Lebanese oil pollution crisis in

  16. Adaptive Urban Dispersion Integrated Model

    SciTech Connect

    Wissink, A; Chand, K; Kosovic, B; Chan, S; Berger, M; Chow, F K

    2005-11-03

    Numerical simulations represent a unique predictive tool for understanding the three-dimensional flow fields and associated concentration distributions from contaminant releases in complex urban settings (Britter and Hanna 2003). Utilization of the most accurate urban models, based on fully three-dimensional computational fluid dynamics (CFD) that solve the Navier-Stokes equations with incorporated turbulence models, presents many challenges. We address two in this work; first, a fast but accurate way to incorporate the complex urban terrain, buildings, and other structures to enforce proper boundary conditions in the flow solution; second, ways to achieve a level of computational efficiency that allows the models to be run in an automated fashion such that they may be used for emergency response and event reconstruction applications. We have developed a new integrated urban dispersion modeling capability based on FEM3MP (Gresho and Chan 1998, Chan and Stevens 2000), a CFD model from Lawrence Livermore National Lab. The integrated capability incorporates fast embedded boundary mesh generation for geometrically complex problems and full three-dimensional Cartesian adaptive mesh refinement (AMR). Parallel AMR and embedded boundary gridding support are provided through the SAMRAI library (Wissink et al. 2001, Hornung and Kohn 2002). Embedded boundary mesh generation has been demonstrated to be an automatic, fast, and efficient approach for problem setup. It has been used for a variety of geometrically complex applications, including urban applications (Pullen et al. 2005). The key technology we introduce in this work is the application of AMR, which allows the application of high-resolution modeling to certain important features, such as individual buildings and high-resolution terrain (including important vegetative and land-use features). It also allows the urban scale model to be readily interfaced with coarser resolution meso or regional scale models. This talk

  17. Use of Various Rock Physics Models Combined with a Rock Physics Database to Better Characterize Velocity Dispersion Effects in Potential Enhanced Oil Recovery, Carbon Sequestration and Hydrothermal Sites

    NASA Astrophysics Data System (ADS)

    Purcell, C. C.; Mur, A. J.; Delany, D.; Haljasmaa, I. V.; Soong, Y.; Harbert, W.

    2011-12-01

    The exploration of velocity differences in various fluid saturated rock types under reservoir conditions should prove to be useful in seismic monitoring of sequestration and hydrothermal sites. Different saturation values, along with mixtures of other common pore fluids could help delineate various areas of a CO2 flood or enhanced geothermal pressurization, in addition to estimating a minimum saturation amount needed to be seen in seismic surveys. We also explore the effects of varying parameters on the saturated velocities, including porosity, bulk frame composition, pressure, temperature, different pore filling phases, fluid mixtures, and compliant porosity. A software toolkit is currently in development that would allow exploration of these parameters to be easily achieved and visualized. Fluid substitution using Gassmann's equation (Gassmann [1]) is an important tool in the analysis of velocity dispersion in saturated rocks. Mavko and Jizba [2] created a model of squirt dispersion for elastic wave velocities at ultrasonic frequencies that predicts total dispersion for fluid filled rocks. Gurevich et al. [3] extend the Mavko-Jizba expressions to low fluid bulk modulus situations, such as gas filled rocks. These equations are typically used to calculate velocities of rocks filled with typical pore filling phases such as brine or gas. Purcell et al. [4] compared these equations to CO2 saturated limestone samples at reservoir pressures and temperatures. This paper compares the accuracy of these equations over various pressures and temperature ranges for a variety of rock types. Dry rock ultrasonic lab measurements of velocity have been made for carbonate, sandstone, rhyolite and coal and incorporated into a rock physics database. In addition, waveforms for each measurement have been used to estimate Q. Measurements were made between 2.3 and 50 MPa with generally a minimum of 40 measurements per sample completed. Various saturating phases, including supercritical CO

  18. Pollen Forecast and Dispersion Modelling

    NASA Astrophysics Data System (ADS)

    Costantini, Monica; Di Giuseppe, Fabio; Medaglia, Carlo Maria; Travaglini, Alessandro; Tocci, Raffaella; Brighetti, M. Antonia; Petitta, Marcello

    2014-05-01

    The aim of this study is monitoring, mapping and forecast of pollen distribution for the city of Rome using in-situ measurements of 10 species of common allergenic pollens and measurements of PM10. The production of daily concentration maps, associated to a mobile phone app, are innovative compared to existing dedicated services to people who suffer from respiratory allergies. The dispersal pollen is one of the most well-known causes of allergic disease that is manifested by disorders of the respiratory functions. Allergies are the third leading cause of chronic disease and it is estimated that tens millions of people in Italy suffer from it. Recent works reveal that during the last few years there was a progressive increase of affected subjects, especially in urban areas. This situation may depend: on the ability to transport of pollutants, on the ability to react between pollutants and pollen and from a combination of other irritants, existing in densely populated and polluted urban areas. The methodology used to produce maps is based on in-situ measurements time series relative to 2012, obtained from networks of air quality and pollen stations in the metropolitan area of Rome. The monitoring station aerobiological of University of Rome "Tor Vergata" is located at the Department of Biology. The instrument used to pollen monitoring is a volumetric sampler type Hirst (Hirst 1952), Model 2000 VPPS Lanzoni; the data acquisition is carried out as reported in Standard UNI 11008:2004 - "Qualità dell'aria - Metodo di campionamento e conteggio dei granuli pollinici e delle spore fungine aerodisperse" - the protocol that describes the procedure for measuring of the concentration of pollen grains and fungal spores dispersed into the atmosphere, and reported in the "Manuale di gestione e qualità della R.I.M.A" (Travaglini et. al. 2009). All 10 allergenic pollen are monitored since 1996. At Tor Vergata university is also operating a meteorological station (SP2000, CAE

  19. Effects of a chemical dispersant and crude oil on breeding ducks

    USGS Publications Warehouse

    Albers, P.H.; Gay, M.L.

    1982-01-01

    Effects of chemically dispersed crude oil on mallard reproduction. Incubating female mallards were exposed to a water source treated with either Prudhoe Bay crude oil, Corexit 9527, or a combination of oil and dispersant during the first 10 da of development. Used thermocouple probes to monitor incubation temperature. Measured hatching success, incubation temperature, and survival of ducklings to 1 wk of age.

  20. How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods.

    PubMed

    Almeda, Rodrigo; Connelly, Tara L; Buskey, Edward J

    2016-01-01

    We investigated and quantified defecation rates of crude oil by 3 species of marine planktonic copepods (Temora turbinata, Acartia tonsa, and Parvocalanus crassirostris) and a natural copepod assemblage after exposure to mechanically or chemically dispersed crude oil. Between 88 and 100% of the analyzed fecal pellets from three species of copepods and a natural copepod assemblage exposed for 48 h to physically or chemically dispersed light crude oil contained crude oil droplets. Crude oil droplets inside fecal pellets were smaller (median diameter: 2.4-3.5 μm) than droplets in the physically and chemically dispersed oil emulsions (median diameter: 6.6 and 8.0 μm, respectively). This suggests that copepods can reject large crude oil droplets or that crude oil droplets are broken into smaller oil droplets before or during ingestion. Depending on the species and experimental treatments, crude oil defecation rates ranged from 5.3 to 245 ng-oil copepod(-1) d(-1), which represent a mean weight-specific defecation rate of 0.026 μg-oil μg-Ccopepod(1) d(-1). Considering a dispersed crude oil concentration commonly found in the water column after oil spills (1 μl L(-1)) and copepod abundances in high productive coastal areas, copepods may defecate ∼ 1.3-2.6 mg-oil m(-3) d(-1), which would represent ∼ 0.15%-0.30% of the total dispersed oil per day. Our results indicate that ingestion and subsequent defecation of crude oil by planktonic copepods has a small influence on the overall mass of oil spills in the short term, but may be quantitatively important in the flux of oil from surface water to sediments and in the transfer of low-solubility, toxic petroleum hydrocarbons into food webs after crude oil spills in the sea. PMID:26586632

  1. Biodegradability of Corexit 9500 and Dispersed South Louisiana Crude Oil at 5 and 25oC

    EPA Science Inventory

    The reported persistence of the dioctyl sodium sulfosuccinate (DOSS) surfactant in Corexit 9500 in the oil plumes formed during the Deepwater Horizon oil spill has contributed to the concerns regarding the biodegradability and bioavailability of dispersed oil and dispersants used...

  2. Effects of chemical dispersants and mineral fines on crude oil dispersion in a wave tank under breaking waves.

    PubMed

    Li, Zhengkai; Kepkay, Paul; Lee, Kenneth; King, Thomas; Boufadel, Michel C; Venosa, Albert D

    2007-07-01

    The interaction of chemical dispersants and suspended sediments with crude oil influences the fate and transport of oil spills in coastal waters. A wave tank study was conducted to investigate the effects of chemical dispersants and mineral fines on the dispersion of oil and the formation of oil-mineral-aggregates (OMAs) in natural seawater. Results of ultraviolet spectrofluorometry and gas chromatography flame ionized detection analysis indicated that dispersants and mineral fines, alone and in combination, enhanced the dispersion of oil into the water column. Measurements taken with a laser in situ scattering and transmissometer (LISST-100X) showed that the presence of mineral fines increased the total concentration of the suspended particles from 4 to 10microl l(-1), whereas the presence of dispersants decreased the particle size (mass mean diameter) of OMAs from 50 to 10microm. Observation with an epifluorescence microscope indicated that the presence of dispersants, mineral fines, or both in combination significantly increased the number of particles dispersed into the water. PMID:17433372

  3. Simulating oil droplet dispersal from the Deepwater Horizon spill with a Lagrangian approach

    USGS Publications Warehouse

    North, Elizabeth W.; Adams, E. Eric; Sherwood, Christopher R.; He, Ruoying; Hyun, Kyung Hoon; Socolofsky, Scott A.; Schlag, Zachary

    2011-01-01

    An analytical multiphase plume model, combined with time-varying flow and hydrographic fields generated by the 3-D South Atlantic Bight and Gulf of Mexico model (SABGOM) hydrodynamic model, were used as input to a Lagrangian transport model (LTRANS), to simulate transport of oil droplets dispersed at depth from the recent Deepwater Horizon MC 252 oil spill. The plume model predicts a stratification-dominated near field, in which small oil droplets detrain from the central plume containing faster rising large oil droplets and gas bubbles and become trapped by density stratification. Simulated intrusion (trap) heights of ∼ 310–370 m agree well with the midrange of conductivity-temperature-depth observations, though the simulated variation in trap height was lower than observed, presumably in part due to unresolved variability in source composition (percentage oil versus gas) and location (multiple leaks during first half of spill). Simulated droplet trajectories by the SABGOM-LTRANS modeling system showed that droplets with diameters between 10 and 50 μm formed a distinct subsurface plume, which was transported horizontally and remained in the subsurface for >1 month. In contrast, droplets with diameters ≥90 μm rose rapidly to the surface. Simulated trajectories of droplets ≤50 μm in diameter were found to be consistent with field observations of a southwest-tending subsurface plume in late June 2010 reported by Camilli et al. [2010]. Model results suggest that the subsurface plume looped around to the east, with potential subsurface oil transport to the northeast and southeast. Ongoing work is focusing on adding degradation processes to the model to constrain droplet dispersal.

  4. Growth and immune system performance to assess the effect of dispersed oil on juvenile sea bass (Dicentrarchus labrax).

    PubMed

    Dussauze, Matthieu; Danion, Morgane; Floch, Stéphane Le; Lemaire, Philippe; Theron, Michaël; Pichavant-Rafini, Karine

    2015-10-01

    The potential impact of chemically and mechanically dispersed oil was assessed in a model fish of European coastal waters, the sea bass Dicentrarchus labrax. Juvenile sea bass were exposed for 48h to dispersed oil (mechanically and chemically) or dispersants alone. The impact of these exposure conditions was assessed using growth and immunity. The increase observed in polycyclic aromatic hydrocarbon metabolites in bile indicated oil contamination in the fish exposed to chemical and mechanical dispersion of oil without any significant difference between these two groups. After 28 days of exposure, no significant differences were observed in specific growth rate,apparent food conversion efficiency and daily feeding). Following the oil exposure, fish immunity was assessed by a challenge with Viral Nervous Necrosis Virus (VNNV). Fish mortality was observed over a 42 day period. After 12 days post-infection, cumulative mortality was significantly different between the control group (16% p≤0.05) and the group exposed to chemical dispersion of oil (30% p≤0.05). However, at the end of the experiment, no significant difference was recorded in cumulative mortality or in VNNV antibodies secreted in fish in responses to the treatments. These data suggested that in our experimental condition, following the oil exposure, sea bass growth was not affected whereas an impact on immunity was observed during the first days. However, this effect on the immune system did not persist over time. PMID:26092553

  5. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    PubMed

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  6. Effects of corexit oil dispersants and the WAF of dispersed oil on DNA damage and repair in cultured human bronchial airway cells, BEAS-2B

    PubMed Central

    Major, Danielle; Derbes, Rebecca S.; Wang, He; Roy-Engel, Astrid M.

    2016-01-01

    Large quantities of dispersants were used as a method to disperse the roughly 210 million gallons of spilled crude oil that consumed the Gulf of Mexico. Little is known if the oil-dispersant and oil-dispersant mixtures on human airway BEAS-2B epithelial cells. Here we present the cytotoxic and genotoxic in vitro effects on the human lung cells BEAS-2B following exposure to and oil-dispersant mixtures on human airway BEAS-2B epithelial cells. Here we present the cytotoxic and genotoxic in vitro effects on the human lung cells BEAS-2B following exposure to Corexit dispersants EC9500 and EC9527, Water Accommodated Fraction (WAF) -crude, WAF-9500 + Oil, and WAF-9527 + Oil. Cellular cytotoxicity to WAF-dispersed oil samples was observed at concentrations greater than 1000 ppm with over 70% of observed cellular death. At low concentration exposures (100 and 300 ppm) DNA damage was evidenced by the detection of single strand breaks (SSBs) and double strand breaks (DSBs) as measured by alkaline and neutral comet assay analyses. Immunoblot analyses of the phosphorylated histone H2A.X (ɣ-H2A.X) and tumor suppressor p53 protein confirmed activation of the DNA damage response due to the exposure-induced DNA breaks. Although, many xenobiotics interfere with DNA repair pathways, in vitro evaluation of the nucleotide excision repair (NER) and DSB repair pathways appear to be unaffected by the oil-dispersant mixtures tested. Overall, this study supports that oil-dispersant mixtures induce genotoxic effects in culture.

  7. Tests for oil/dispersant toxicity: In situ laboratory assays

    SciTech Connect

    Wright, D.A.; Coelho, G.M.; Aurand, D.V.

    1995-12-31

    As part of its readiness program in oil spill response, the Marine Pollution Control Unit (MPCU), Department of Transport, U.K. conducts annual field trials in the North Sea, approximately 30 nautical miles from the southeast coast of England. The trials take the form of controlled releases of crude oil or Medium Fuel/Gas Oil mix (MFO), with and without the application of Corexit 9527 dispersant. In 1994 and 1995 the authors conducted a series of in situ toxicity bioassays in association with these spills with included 48h LC50 tests for turbot (Scophthalmus maximus) and oyster (Crassostrea gigas) larvae, a 48 h oyster (C. gigas) embryonic development test and two full life-cycle assays using the copepods Acartia tonsa and Tisbe battagliai. Tests were also conducted in the Chesapeake Bay laboratory using estuarine species including the copepod Eurytemora affinis and the inland silverside Menidia beryllina. Here, the authors report on the results of these assays, together with 1996 in situ toxicity data resulting from Norwegian field trials in the northern North Sea.

  8. Simple test for toxicity of number 2 fuel oil and oil dispersants to embryos of grass shrimp, palaemonetes pugio

    SciTech Connect

    Fisher, W.S.; Foss, S.S.

    1993-01-01

    A simple test, using embryos of the grass shrimp Palaemonetes pugio, was employed to determine the toxicity of two commercial oil dispersants (Corexit 7664 and Corexit 9527) and toxicity of the water soluble fraction of Number 2 fuel oil (WSF oil) prepared with and without the addition of the dispersants. Tests revealed P. pugio embryos were similar to previously measured life stages in their sensitivity to WSF oil prepared without dispersants. They were approximately ten times more sensitive to water soluble fractions of dispersed oil, which may have been due to the approximately ten-fold increases in total hydrocarbons measured analytically. Both temperatures and salinity of the sea water affected toxicity of WSF prepared with dispersants, the most obvious effect being earlier onset of mortalities at higher temperatures. (Copyright (c) 1993 Pergamon Press Ltd.)

  9. Biodegradation of dispersed Macondo crude oil by indigenous Gulf of Mexico microbial communities.

    PubMed

    Wang, Jian; Sandoval, Kathia; Ding, Yan; Stoeckel, Donald; Minard-Smith, Angela; Andersen, Gary; Dubinsky, Eric A; Atlas, Ronald; Gardinali, Piero

    2016-07-01

    Because of the extreme conditions of the Deepwater Horizon (DWH) release (turbulent flow at 1500m depth and 5°C water temperature) and the sub-surface application of dispersant, small but neutrally buoyant oil droplets <70μm were formed, remained in the water column and were subjected to in-situ biodegradation processes. In order to investigate the biodegradation of Macondo oil components during the release, we designed and performed an experiment to evaluate the interactions of the indigenous microbial communities present in the deep waters of the Gulf of Mexico (GOM) with oil droplets of two representative sizes (10μm and 30μm median volume diameter) created with Macondo source oil in the presence of Corexit 9500 using natural seawater collected at the depth of 1100-1300m in the vicinity of the DWH wellhead. The evolution of the oil was followed in the dark and at 5°C for 64days by collecting sacrificial water samples at fixed intervals and analyzing them for a wide range of chemical and biological parameters including volatile components, saturated and aromatic hydrocarbons, dispersant markers, dissolved oxygen, nutrients, microbial cell counts and microbial population dynamics. A one phase exponential decay from a plateau model was used to calculate degradation rates and lag times for more than 150 individual oil components. Calculations were normalized to a conserved petroleum biomarker (30αβ-hopane). Half-lives ranged from about 3days for easily degradable compounds to about 60days for higher molecular weight aromatics. Rapid degradation was observed for BTEX, 2-3 ring PAHs, and n-alkanes below n-C23. The results in this experimental study showed good agreement with the n-alkane (n-C13 to n-C26) half-lives (0.6-9.5days) previously reported for the Deepwater Horizon plume samples and other laboratory studies with chemically dispersed Macondo oil conducted at low temperatures (<8°C). The responses of the microbial populations also were consistent with

  10. An initial probabilistic hazard assessment of oil dispersants approved by the United States National Contingency Plan.

    PubMed

    Berninger, Jason P; Williams, E Spencer; Brooks, Bryan W

    2011-07-01

    Dispersants are commonly applied during oil spill mitigation efforts; however, these industrial chemicals may present risks to aquatic organisms individually and when mixed with oil. Fourteen dispersants are listed on the U.S. Environmental Protection Agency (U.S. EPA) National Oil and Hazardous Substances Pollution Contingency Plan (NCP). Availability of environmental effects information for such agents is limited, and individual components of dispersants are largely proprietary. Probabilistic hazard assessment approaches including Chemical Toxicity Distributions (CTDs) may be useful as an initial step toward prioritizing environmental hazards from the use of dispersants. In the present study, we applied the CTD approach to two acute toxicity datasets: NCP (the contingency plan dataset) and DHOS (a subset of NCP listed dispersants reevaluated subsequent to the Deepwater Horizon oil spill). These datasets contained median lethal concentration (LC50) values for dispersants alone and dispersant:oil mixtures, in two standard marine test species, Menidia beryllina and Mysidopsis bahia. These CTDs suggest that dispersants alone are generally less toxic than oil. In contrast, most dispersant:oil mixtures are more toxic than oil alone. For the two datasets (treated separately because of differing methodologies), CTDs would predict 95% of dispersant:oil mixtures to have acute toxicity values above 0.32 and 0.76 mg/L for Mysidopsis and 0.33 mg/L and 1.06 mg/L for Menidia (for DHOS and NCP, respectively). These findings demonstrate the utility of CTDs as a means to evaluate the comparative ecotoxicity of dispersants alone and in mixture with different oil types. The approaches presented here also provide valuable tools for prioritizing prospective and retrospective environmental assessments of oil dispersants. PMID:21425326

  11. Toxicity of dispersant Corexit 9500A and crude oil to marine microzooplankton.

    PubMed

    Almeda, Rodrigo; Hyatt, Cammie; Buskey, Edward J

    2014-08-01

    In 2010, nearly 7 million liters of chemical dispersants, mainly Corexit 9500A, were released in the Gulf of Mexico to treat the Deepwater Horizon oil spill. However, little is still known about the effects of Corexit 9500A and dispersed crude oil on microzooplankton despite the important roles of these planktonic organisms in marine ecosystems. We conducted laboratory experiments to determine the acute toxicity of Corexit 9500A, and physically and chemically dispersed Louisiana light sweet crude oil to marine microzooplankton (oligotrich ciliates, tintinnids and heterotrophic dinoflagellates). Our results indicate that Corexit 9500A is highly toxic to microzooplankton, particularly to small ciliates, and that the combination of dispersant with crude oil significantly increases the toxicity of crude oil to microzooplankton. The negative impact of crude oil and dispersant on microzooplankton may disrupt the transfer of energy from lower to higher trophic levels and change the structure and dynamics of marine planktonic communities. PMID:24836881

  12. Dispersion of T1 and T2 nuclear magnetic resonance relaxation in crude oils.

    PubMed

    Chen, Joseph J; Hürlimann, Martin; Paulsen, Jeffrey; Freed, Denise; Mandal, Soumyajit; Song, Yi-Qiao

    2014-09-15

    Crude oils, which are complex mixtures of hydrocarbons, can be characterized by nuclear magnetic resonance diffusion and relaxation methods to yield physical properties and chemical compositions. In particular, the field dependence, or dispersion, of T1 relaxation can be used to investigate the presence and dynamics of asphaltenes, the large molecules primarily responsible for the high viscosity in heavy crudes. However, the T2 relaxation dispersion of crude oils, which provides additional insight when measured alongside T1, has yet to be investigated systematically. Here we present the field dependence of T1-T2 correlations of several crude oils with disparate densities. While asphaltene and resin-containing crude oils exhibit significant T1 dispersion, minimal T2 dispersion is seen in all oils. This contrasting behavior between T1 and T2 cannot result from random molecular motions, and thus, we attribute our dispersion results to highly correlated molecular dynamics in asphaltene-containing crude oils. PMID:24919743

  13. Dispersants have limited effects on exposure rates of oil spills on fish eggs and larvae in shelf seas.

    PubMed

    Vikebø, Frode B; Rønningen, Petter; Meier, Sonnich; Grøsvik, Bjørn Einar; Lien, Vidar S

    2015-05-19

    Early life stages of fish are particularly vulnerable to oil spills. Simulations of overlap of fish eggs and larvae with oil from different oil-spill scenarios, both without and with the dispersant Corexit 9500, enable quantitative comparisons of dispersants as a mitigation alternative. We have used model simulations of a blow out of 4500 m(3) of crude oil per day (Statfjord light crude) for 30 days at three locations along the Norwegian coast. Eggs were released from nine different known spawning grounds, in the period from March 1st until the end of April, and all spawning products were followed for 90 days from the spill start at April first independent of time for spawning. We have modeled overlap between spawning products and oil concentrations giving a total polycyclic hydrocarbon (TPAH) concentration of more than 1.0 or 0.1 ppb (μg/l). At these orders of magnitude, we expect acute mortality or sublethal effects, respectively. In general, adding dispersants results in higher concentrations of TPAHs in a reduced volume of water compared to not adding dispersants. Also, the TPAHs are displaced deeper in the water column. Model simulations of the spill scenarios showed that addition of chemical dispersant in general moderately decreased the fraction of eggs and larvae that were exposed above the selected threshold values. PMID:25875213

  14. SIMPLE TEST FOR TOXICITY OF NUMBER 2 FUEL OIL AND OIL DISPERSANTS TO EMBRYOS OF GRASS SHRIMP, PALAEMONETES PUGIO

    EPA Science Inventory

    A simple test, using embryos of the grass shrimp Palaemonetes pugio, was employed to determine the toxicity of two commercial oil dispersants (Corexit 7664 and Corexit 9527) and toxicity of the water soluble fraction of Number 2 fuel oil (WSF oil) prepared with and without the ad...

  15. Initial community and environment determine the response of bacterial communities to dispersant and oil contamination.

    PubMed

    Ortmann, Alice C; Lu, YueHan

    2015-01-15

    Bioremediation of seawater by natural bacterial communities is one potential response to coastal oil spills, but the success of the approach may vary, depending on geographical location, oil composition and the timing of spill. The short term response of coastal bacteria to dispersant, oil and dispersed oil was characterized using 16S rRNA gene tags in two mesocosm experiments conducted two months apart. Despite differences in the amount of oil-derived alkanes across the treatments and experiments, increases in the contributions of hydrocarbon degrading taxa and decreases in common estuarine bacteria were observed in response to dispersant and/or oil. Between the two experiments, the direction and rates of changes in particulate alkane concentrations differed, as did the magnitude of the bacterial response to oil and/or dispersant. Together, our data underscore large variability in bacterial responses to hydrocarbon pollutants, implying that bioremediation success varies with starting biological and environmental conditions. PMID:25487088

  16. A review of dispersion modelling and its application to the dispersion of particles: An overview of different dispersion models available

    NASA Astrophysics Data System (ADS)

    Holmes, N. S.; Morawska, L.

    This paper provides the first review of the application of atmospheric models for particle dispersion. The different types of dispersion models available, from simple box type models to complex fluid dynamics models are outlined and the suitability of the different approaches to dispersion modelling within different environments, in regards to scale, complexity of the environment and concentration parameters is assessed. Finally, several major commercial and non-commercial particle dispersion packages are reviewed, detailing which processes are included and advantages and limitations of their use to modelling particle dispersion. The models reviewed included: Box models (AURORA, CPB and PBM), Gaussian models (CALINE4, HIWAY2, CAR-FMI, OSPM, CALPUFF, AEROPOL, AERMOD, UK-ADMS and SCREEN3), Lagrangian/Eulerian Models (GRAL, TAPM, ARIA Regional), CFD models (ARIA Local, MISKAM, MICRO-CALGRID) and models which include aerosol dynamics (GATOR, MONO32, UHMA, CIT, AERO, RPM, AEROFOR2, URM-1ATM, MADRID, CALGRID and UNI-AERO).

  17. Combined toxicity of four toxicants (Cu, Cr, oil, oil dispersant) to Artemia salina

    SciTech Connect

    Verriopoulos, G.; Moraitou-Apostolopoulou, M.; Milliou, E.

    1987-03-01

    In sea waters multicontaminant pollution appears to be the rule rather than the exception. For a realistic approach to pollution effects it is essential to estimate the combined toxicity of two or more chemicals. There is a need to understand the mechanisms of quantify the effects of multiple toxicity in order to provide responsible authorities with rational estimate of the effects of chemical mixtures. Thus the potential toxic effects of mixtures of toxicants has recently become a subject of growing scientific interest. In this paper the authors have tried to estimate the joint toxicity of some pollutants commonly found in nearshore polluted waters: two metals, copper and chromium; an oil (Tunesian crude oil zarzaitine type); and an oil dispersant (Finasol OSR-2).

  18. Viscosity index improver-dispersant additive useful in oil compositions

    SciTech Connect

    Gardiner, J.B.; Dick, M.N.

    1988-10-25

    A process comprising grafting in the substantial absence of solvent a hydrocarbon polymer of C/sub 2/ to C/sub 28/ olefin, the polymer having a number average molecular weight in the range of about 5,000 to 500,000 with an unsaturated material selected from the group consisting of: (A) ethylenically unsaturated C/sub 3/ to C/sub 10/ carboxylic acid having 1 to 2 carboxylic acid groups or an anhydride group, and (B) nitrogen-containing ethylenically unsaturated monomers containing 6 to 30 carbon atoms and 1 to 4 nitrogen atoms, in the presence of a free radical initiator and a chain stopping agent comprising at least one member selected from the group consisting of alphatic mercaptans having 4 to 24 carbon atoms, deithyl hydroxyl amine cumene and phenols, the grafting being conducted in a manner and under conditions sufficient to form a substantially oil soluble graft copolymer useful as a viscosity index improver-dispersant additive for lubricating oil compositions.

  19. "Dispersion modeling approaches for near road

    EPA Science Inventory

    Roadway design and roadside barriers can have significant effects on the dispersion of traffic-generated pollutants, especially in the near-road environment. Dispersion models that can accurately simulate these effects are needed to fully assess these impacts for a variety of app...

  20. A laboratory approach for determining the effect of oils and dispersants on mangroves

    SciTech Connect

    Baca, B.J.

    1982-10-01

    An experimental approach was developed and applied to testing the effects of oil and dispersant combinations on the growth of mangrove seedlings (trees of the intertidal tropics). A controlled growth chamber was employed to test the effects of different oils and dispersed oils in an array of dosages applied to different parts of the plants. Preliminary test results are reported for two species of mangroves collected from five localities, including both oiled and unoiled estuaries. Differences occurred between species, substances, dosages, the part of the plant dosed, and the presence of chronic oil pollution at localities from which the stocks were collected. Avicennia germinans (L.) L. (black mangrove) was more sensitive than Rhizophora mangle L. (red mangrove) when exposed to almost all substances tested. Light Arabian crude oil (LA) and light Arabian crude oil dispersed (LAD) were the most toxic substances tested. No. 2 fuel oil (N2) and No. 2 fuel oil dispersed (N2D) were as toxic as LA and LAD, except for an increase (an enhancement effect) in foliage and stem growth in Avicennia at lower dosages. Bunker C oil (BC) was the least toxic of the oils tested, resulting in the reduction of foliage and stem growth only at the highest dosage tested in Avicennia. Bunker C oil dispersed (BCD) failed to show effects in either species at any dosage tested. The leaves of Rhizophora were the most sensitive part of the plant tested.

  1. Application of the multicomponent lattice Boltzmann simulation method to oil/water dispersions

    NASA Astrophysics Data System (ADS)

    Seaton, M. A.; Halliday, I.; Masters, A. J.

    2011-03-01

    We study the propagation of acoustic fields in bounded, two-dimensional, mono-disperse oil/water emulsions using a carefully modified and appropriately calibrated single relaxation time multicomponent lattice Boltzmann equation simulation. Our model is a variant of an algorithm applying both interface forces based on macroscopic surface tensions and a kinematic condition for phase separation, adapted to allow sonic speed variations between its oil and water components. Appropriate second-order accurate acoustic boundary conditions are obtained from a node-based lattice closure with local mass conservation and applicability for varying fluid viscosities. Data from an example simulation of a single oil drop in water interacting with a generated standing acoustic wave are presented and, where appropriate, compared with empirical theories and analogous calculations for a solid object.

  2. Comparative Toxicity of Eight Oil Dispersant Products on Two Gulf of Mexico Aquatic Test Species

    EPA Science Inventory

    This report is the first of a round of toxicity testing data for eight oil dispersants that have been authorized for use on the National Contingency Plan (NCP) Product Schedule, which is a list of authorized dispersants and other chemicals that may be used to respond to oil disch...

  3. Chemical dispersants can suppress the activity of natural oil-degrading microorganisms.

    PubMed

    Kleindienst, Sara; Seidel, Michael; Ziervogel, Kai; Grim, Sharon; Loftis, Kathy; Harrison, Sarah; Malkin, Sairah Y; Perkins, Matthew J; Field, Jennifer; Sogin, Mitchell L; Dittmar, Thorsten; Passow, Uta; Medeiros, Patricia M; Joye, Samantha B

    2015-12-01

    During the Deepwater Horizon oil well blowout in the Gulf of Mexico, the application of 7 million liters of chemical dispersants aimed to stimulate microbial crude oil degradation by increasing the bioavailability of oil compounds. However, the effects of dispersants on oil biodegradation rates are debated. In laboratory experiments, we simulated environmental conditions comparable to the hydrocarbon-rich, 1,100 m deep plume that formed during the Deepwater Horizon discharge. The presence of dispersant significantly altered the microbial community composition through selection for potential dispersant-degrading Colwellia, which also bloomed in situ in Gulf deep waters during the discharge. In contrast, oil addition to deepwater samples in the absence of dispersant stimulated growth of natural hydrocarbon-degrading Marinobacter. In these deepwater microcosm experiments, dispersants did not enhance heterotrophic microbial activity or hydrocarbon oxidation rates. An experiment with surface seawater from an anthropogenically derived oil slick corroborated the deepwater microcosm results as inhibition of hydrocarbon turnover was observed in the presence of dispersants, suggesting that the microcosm findings are broadly applicable across marine habitats. Extrapolating this comprehensive dataset to real world scenarios questions whether dispersants stimulate microbial oil degradation in deep ocean waters and instead highlights that dispersants can exert a negative effect on microbial hydrocarbon degradation rates. PMID:26553985

  4. Chemical dispersants can suppress the activity of natural oil-degrading microorganisms

    PubMed Central

    Kleindienst, Sara; Seidel, Michael; Ziervogel, Kai; Grim, Sharon; Loftis, Kathy; Harrison, Sarah; Malkin, Sairah Y.; Perkins, Matthew J.; Field, Jennifer; Sogin, Mitchell L.; Dittmar, Thorsten; Passow, Uta; Medeiros, Patricia M.; Joye, Samantha B.

    2015-01-01

    During the Deepwater Horizon oil well blowout in the Gulf of Mexico, the application of 7 million liters of chemical dispersants aimed to stimulate microbial crude oil degradation by increasing the bioavailability of oil compounds. However, the effects of dispersants on oil biodegradation rates are debated. In laboratory experiments, we simulated environmental conditions comparable to the hydrocarbon-rich, 1,100 m deep plume that formed during the Deepwater Horizon discharge. The presence of dispersant significantly altered the microbial community composition through selection for potential dispersant-degrading Colwellia, which also bloomed in situ in Gulf deep waters during the discharge. In contrast, oil addition to deepwater samples in the absence of dispersant stimulated growth of natural hydrocarbon-degrading Marinobacter. In these deepwater microcosm experiments, dispersants did not enhance heterotrophic microbial activity or hydrocarbon oxidation rates. An experiment with surface seawater from an anthropogenically derived oil slick corroborated the deepwater microcosm results as inhibition of hydrocarbon turnover was observed in the presence of dispersants, suggesting that the microcosm findings are broadly applicable across marine habitats. Extrapolating this comprehensive dataset to real world scenarios questions whether dispersants stimulate microbial oil degradation in deep ocean waters and instead highlights that dispersants can exert a negative effect on microbial hydrocarbon degradation rates. PMID:26553985

  5. Flow development investigation of concentrated unstable oil-water dispersions in turbulent pipe flows

    NASA Astrophysics Data System (ADS)

    Voulgaropoulos, Victor; Weheliye, Weheliye; Chinaud, Maxime; Angeli, Panagiota; Karolina Ioannou Collaboration

    2015-11-01

    This study explores the separation characteristics of unstable oil-water dispersed flows in pipes. The test section is a 7 m long acrylic pipe with a 37mm ID and the fluids used are tap water and an Exxsol oil (6.6cSt) An inlet system with more than a thousand capillary tubes of 1mm ID is implemented to actuate highly concentrated dispersions for a wider range of flow rates. High speed imaging combined with ring conductivity probes and pressure transducers are implemented in several axial positions along the pipe to study the flow development. Phase distribution and continuity are measured in the pipe cross-section and drop size information is acquired by high frequency dual impedance probes. The coalescence and sedimentation dynamics of the concentrated dispersions and the development of separate layers downstream the pipe are investigated. The experimental results are coupled with theoretical and semi-empirical models in an effort to predict the separation properties of the highly concentrated dispersed flows. Chevron Energy Technology, Houston, USA.

  6. Oil plumes and dispersion in Langmuir, upper-ocean turbulence: Large-eddy simulations and K-profile parameterization

    NASA Astrophysics Data System (ADS)

    Yang, Di; Chen, Bicheng; Chamecki, Marcelo; Meneveau, Charles

    2015-07-01

    Once oil plumes such as those originating from underwater blowouts reach the ocean mixed layer (OML), their near-surface dispersion is influenced heavily by wind and wave-generated Langmuir turbulence. In this study, the complex oil spill dispersion process is modeled using large-eddy simulation (LES). The mean plume dispersion is characterized by performing statistical analysis of the resulting fields from the LES data. Although the instantaneous oil concentration exhibits high intermittency with complex spatial patterns such as Langmuir-induced striations, it is found that the time-averaged oil distribution can still be described quite well by smooth Gaussian-type plumes. LES results show that the competition between droplet rise velocity and vertical turbulent diffusion due to Langmuir turbulence is crucial in determining both the dilution rate and overall direction of transport of oil plumes in the OML. The smoothness of the mean plume makes it feasible to aim at modeling the oil dispersion using Reynolds-averaged type formulations, such as the K-profile parameterization (KPP) with sufficient vertical resolution to capture vertical profiles in the OML. Using LES data, we evaluate the eddy viscosity and eddy diffusivity following the KPP framework. We assess the performance of previous KPP models for pure shear turbulence and Langmuir turbulence by comparing them with the LES data. Based on the assessment a modified KPP model is proposed, which shows improved overall agreement with the LES results for both the eddy viscosity and the eddy diffusivity of the oil dispersion under a variety of flow conditions and droplet sizes.

  7. Acute toxicity of chemically and mechanically dispersed crude oil to juvenile sea bass (Dicentrarchus labrax): Absence of synergistic effects between oil and dispersants.

    PubMed

    Dussauze, Matthieu; Pichavant-Rafini, Karine; Le Floch, Stéphane; Lemaire, Philippe; Theron, Michaël

    2015-07-01

    The goal of the present experiment was to assess the relative acute toxicities of mechanically and chemically dispersed oil (crude Arabian Light) in controlled conditions. Juvenile sea bass (Dicentrarchus labrax) were exposed to 4 commercial formulations of dispersants (Corexit EC9500A, Dasic Slickgone NS, Finasol OSR 52, Inipol IP 90), to mechanically dispersed oil, and to the corresponding chemical dispersions. Acute toxicity was evaluated at 24 h, 48 h, 72 h, and 96 h through the determination of 10%, 50%, and 90% lethal concentrations calculated from measured total petroleum hydrocarbon (TPH) concentrations; Kaplan-Meyer mortality analyses were based on nominal concentrations. Animals were exposed to the dissolved fraction of the oil and to the oil droplets (ranging from 14.0 μm to 42.3 μm for the chemical dispersions). Kaplan-Meyer analyses demonstrated an increased mortality in the case of chemical dispersions. This difference can be attributed mainly to differences in TPH, because the chemical lethal concentrations were not reduced compared with mechanical lethal concentrations (except after 24 h of exposure). The ratios of lethal concentrations of mechanical dispersions to the different chemical dispersions were calculated to allow direct comparisons of the relative toxicities of the dispersions. The results ranged from 0.27 to 3.59, with a mean ratio close to 1 (0.92). These results demonstrate an absence of synergistic effect between oil and chemical dispersants in an operational context. PMID:25677812

  8. Physical models of polarization mode dispersion

    SciTech Connect

    Menyuk, C.R.; Wai, P.K.A.

    1995-12-31

    The effect of randomly varying birefringence on light propagation in optical fibers is studied theoretically in the parameter regime that will be used for long-distance communications. In this regime, the birefringence is large and varies very rapidly in comparison to the nonlinear and dispersive scale lengths. We determine the polarization mode dispersion, and we show that physically realistic models yield the same result for polarization mode dispersion as earlier heuristic models that were introduced by Poole. We also prove an ergodic theorem.

  9. Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity

    PubMed Central

    Overholt, Will A.; Marks, Kala P.; Romero, Isabel C.; Hollander, David J.; Snell, Terry W.

    2015-01-01

    The Deepwater Horizon blowout in April 2010 represented the largest accidental marine oil spill and the largest release of chemical dispersants into the environment to date. While dispersant application may provide numerous benefits to oil spill response efforts, the impacts of dispersants and potential synergistic effects with crude oil on individual hydrocarbon-degrading bacteria are poorly understood. In this study, two environmentally relevant species of hydrocarbon-degrading bacteria were utilized to quantify the response to Macondo crude oil and Corexit 9500A-dispersed oil in terms of bacterial growth and oil degradation potential. In addition, specific hydrocarbon compounds were quantified in the dissolved phase of the medium and linked to ecotoxicity using a U.S. Environmental Protection Agency (EPA)-approved rotifer assay. Bacterial treatment significantly and drastically reduced the toxicity associated with dispersed oil (increasing the 50% lethal concentration [LC50] by 215%). The growth and crude oil degradation potential of Acinetobacter were inhibited by Corexit by 34% and 40%, respectively; conversely, Corexit significantly enhanced the growth of Alcanivorax by 10% relative to that in undispersed oil. Furthermore, both bacterial strains were shown to grow with Corexit as the sole carbon and energy source. Hydrocarbon-degrading bacterial species demonstrate a unique response to dispersed oil compared to their response to crude oil, with potentially opposing effects on toxicity. While some species have the potential to enhance the toxicity of crude oil by producing biosurfactants, the same bacteria may reduce the toxicity associated with dispersed oil through degradation or sequestration. PMID:26546426

  10. Determining The Dispersibility Of South Louisiana Crude Oil By Eight Oil Dispersant Products Listed On The NCP Product Schedule

    EPA Science Inventory

    We recently conducted a laboratory study to measure the dispersion effectiveness of eight dispersants currently listed on the National Contingency Plan Product Schedule. Results are useful in determining how many commercial dispersant products would have been effective for use o...

  11. Submersible optical sensors exposed to chemically dispersed crude oil: wave tank simulations for improved oil spill monitoring.

    PubMed

    Conmy, Robyn N; Coble, Paula G; Farr, James; Wood, A Michelle; Lee, Kenneth; Pegau, W Scott; Walsh, Ian D; Koch, Corey R; Abercrombie, Mary I; Miles, M Scott; Lewis, Marlon R; Ryan, Scott A; Robinson, Brian J; King, Thomas L; Kelble, Christopher R; Lacoste, Jordanna

    2014-01-01

    In situ fluorometers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track the subsea oil plume. Uncertainties regarding instrument specifications and capabilities necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Dynamic ranges of the Chelsea Technologies Group AQUAtracka, Turner Designs Cyclops, Satlantic SUNA and WET Labs, Inc. ECO, exposed to fresh and artificially weathered crude oil, were determined. Sensors were standardized against known oil volumes and total petroleum hydrocarbons and benzene-toluene-ethylbenzene-xylene measurements-both collected during spills, providing oil estimates during wave tank dilution experiments. All sensors estimated oil concentrations down to 300 ppb oil, refuting previous reports. Sensor performance results assist interpretation of DWH oil spill data and formulating future protocols. PMID:24377909

  12. Efficient dispersion of crude oil by blends of food-grade surfactants: Toward greener oil-spill treatments.

    PubMed

    Riehm, David A; Neilsen, John E; Bothun, Geoffrey D; John, Vijay T; Raghavan, Srinivasa R; McCormick, Alon V

    2015-12-15

    Effectiveness of oil spill dispersants containing lecithin/Tween 80 (L/T) blends in ethanol was measured as a function of L:T ratio, surfactant:solvent ratio, solvent composition, and dispersant:oil ratio (DOR) using baffled flask dispersion effectiveness tests. Optimal L:T ratios are between 60:40 and 80:20 (w/w); at higher L:T ratios, effectiveness is limited by high interfacial tension, while at lower L:T ratios, insufficient lecithin is present to form a well-packed monolayer at an oil-water interface. These optimal L:T ratios retain high effectiveness at low DOR: 80:20 (w/w) L:T dispersant is 89% effective at 1:25 DOR (v/v) and 77% effective at 1:100 DOR (v/v). Increasing surfactant:solvent ratio increases dispersant effectiveness even when DOR is proportionally reduced to keep total surfactant concentration dosed into the oil constant. Replacing some of the ethanol with octane or octanol also increases dispersant effectiveness, suggesting that ethanol's hydrophilicity lowers dispersant-oil miscibility, and that more hydrophobic solvents would increase effectiveness. PMID:26589641

  13. Thermal and rheological properties of carbon nanotube-in-oil dispersions

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Grulke, Eric A.; Zhang, Z. George; Wu, Gefei

    2006-06-01

    Prior work on asymmetric thermally conducting nanoparticle dispersions has shown that it is possible to raise the thermal conductivity of low thermal conductivity liquids at modest volume fractions of nanoparticles. Stable and reproducible nanotube dispersions require careful control of the dispersant chemistry as well as an understanding of their response to input energy. This paper addresses the effects of dispersant concentration, dispersing energy, and nanoparticle loading on thermal conductivity and steady shear viscosity of nanotube-in-oil dispersions. The thermal conductivity and viscosity of these dispersions correlate with each other and vary with the size of large scale agglomerates, or clustered nanoparticles, in the fluids. Fluids with large scale agglomerates have high thermal conductivities. Dispersion energy, applied by sonication, can decrease agglomerate size, but also breaks the nanotubes, decreasing both the thermal conductivity and viscosity of nanotube dispersions. Developing practical heat transfer fluids containing nanoparticles may require a balance between the thermal conductivity and viscosity of the dispersions.

  14. Numerical Modelling of Mesoscale Atmospheric Dispersion.

    NASA Astrophysics Data System (ADS)

    Moran, Michael D.

    Mesoscale atmospheric dispersion is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays a more important role on the mesoscale, and horizontal dispersion can be enhanced and even dominated by vertical wind shear through either the simultaneous or delayed interaction of horizontal differential advection and vertical mixing over one or two diurnal periods. The CSU mesoscale atmospheric dispersion modelling system has been used in this study to simulate the transport and diffusion of a perfluorocarbon gas for episodic releases made during two North American mesoscale dispersion field experiments, the 1980 Great Plains tracer experiment and the 1983 Cross-Appalachian Tracer Experiment (CAPTEX). Ground -level and elevated tracer concentrations were measured out to distances of 600 km from the source in the first experiment and 1100 km in the second. The physiography of the two experimental domains was quite different, permitting isolation and examination of the roles of terrain forcing and differential advection in mesoscale atmospheric dispersion. Suites of numerical experiments of increasing complexity were carried out for both case studies. The experiments differed in the realism of their representation of both the synoptic-scale flow and the underlying terrain. The Great Plains nocturnal low-level jet played an important role in the first case while temporal changes in the synoptic -scale flow were very significant in the second case. The contributions of differential advection and mesoscale deformation to mesoscale dispersion dominated those of small-scale turbulent diffusion for both cases, and Pasquill's (1962) delayed-shear-enhancement mechanism for lateral dispersion was found to be particularly important. This study was also the first quantitative evaluation of the CSU mesoscale dispersion modelling system with

  15. Dispersal

    USGS Publications Warehouse

    2001-01-01

    The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.

  16. Analytic models of warm plasma dispersion relations

    SciTech Connect

    Seough, J. J.; Yoon, P. H.

    2009-09-15

    The present paper is concerned with analytic models of warm plasma dispersion relations for electromagnetic waves propagating parallel to the ambient magnetic field. Specifically, effects of finite betas on two slow modes, namely, the left-hand circularly polarized ion-cyclotron mode and the right-hand circularly polarized whistler mode, are investigated. Analytic models of the warm plasma dispersion relations are constructed on the basis of conjecture and upon comparisons with numerically found roots. It is shown that the model solutions are good substitutes for actual roots. The significance of the present work in the context of nonlinear plasma research is discussed.

  17. Oil droplet interaction with suspended sediment in the seawater column: influence of physical parameters and chemical dispersants.

    PubMed

    Sørensen, Lisbet; Melbye, Alf G; Booth, Andy M

    2014-01-15

    The interaction of dispersed oil droplets with large diameter suspended particulate materials (SPM) has been little studied. In the current study, particle size, oil characteristics and chemical dispersant significantly influence the adsorption of oil droplets to SPM in seawater. Sediments with a smaller particulate size (clay) approaching that of the oil droplets (2-20 μm) adsorbed more oil per gram than sediments with large particle size (sand). Heavier, more polar oils with a high asphaltene content adsorbed more efficiently to SPM than lighter, less polar oils. A decrease in the smaller, more water soluble oil components in the sediment adsorbed oil was observed for all oil types. Addition of chemical dispersant decreased the adsorption of oil droplets to suspended carbonate sand in an exponential-like manner. No change in the relative distribution of compounds adsorbed to the sediment was observed, indicating dispersants do not alter the dissolution of compounds from oil droplets. PMID:24257650

  18. Breakup of an oil slick mixed with dispersants by breaking wave

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Holser, Anne; Katz, Joseph

    2013-11-01

    After oil spill, coherent oil slick are entrained by breaking ocean waves together with air, which produces a complicated three-phase flow, involving a wide range of length and time scales. The oil droplet size distribution is a crucial factor affecting the physical and chemical dispersion of oil spills, but little is known about oil droplet formation mechanism and droplet size distributions during and immediately after the impact of breaking waves. In our experimental study, we investigate the breakup of an oil slick in a specialized wave tank. The widely used dispersant Coexist 9500-A at different dispersant to oil ratio is used for varying the surface tension of crude oil (MC252 surrogate) in the 10 - 1 to 10 mN/m range. The dispersant is applied either by premixing or surface spraying, the latter consistent with typical application. The results include high-speed images of the oil and bubbles' entrainment, showing the resulting formation of a series of droplet clouds during multiple ``plunges'' associated with a single propagating breaking wave. High-speed inline digital holographic cinematography is employed to quantify the oil droplet size distribution, and the impact of droplet-bubble interactions on the entrainment process for varying Weber numbers, and wave properties, from spilling to plunging breakers. Supported by Gulf of Mexico Research Initiative (GoMRI).

  19. DISPERSION OF POLLUTANTS NEAR HIGHWAYS. DATA ANALYSIS AND MODEL EVALUATION

    EPA Science Inventory

    The validity of various assumptions underlying mathematical modeling of pollutant dispersion near at-grade highways was examined and the simulation capability of various dispersion models determined. The data base generated during the Long Island Dispersion Experiment is used to ...

  20. Toxicity of oil and dispersed oil to the eggs and larvae of seven marine fish and invertebrates from the Gulf of Mexico

    SciTech Connect

    Fucik, K.W.; Carr, K.A.; Balcom, B.J.

    1995-06-01

    The early life stages of seven invertebrate and vertebrate species from the Gulf of Mexico were exposed to two oils, Corexit 9527, and dispersed oil mixtures. Chemical analyses found that hydrocarbon concentrations between exposures were relatively consistent. The hydrocarbon concentrations were initially highest in the dispersed oil mixtures compared to the water accommodated fractions (WAF) of the oils. However, hydrocarbon concentrations in both dispersed oil and WAF exposures were generally similar after 24 hours. The levels of toxicity in the dispersed oil mixtures were not proportionately greater than that in the WAF.

  1. Oil and air dispersion in a simulated fermentation broth as a function of mycelial morphology.

    PubMed

    Lucatero, Savidra; Larralde-Corona, Claudia Patricia; Corkidi, Gabriel; Galindo, Enrique

    2003-01-01

    The culture conditions of a multiphase fermentation involving morphologically complex mycelia were simulated in order to investigate the influence of mycelial morphology (Trichoderma harzianum) on castor oil and air dispersion. Measurements of oil drops and air bubbles were obtained using an image analysis system coupled to a mixing tank. Complex interactions of the phases involved could be clearly observed. The Sauter diameter and the size distributions of drops and bubbles were affected by the morphological type of biomass (pellets or dispersed mycelia) added to the system. Larger oil drop sizes were obtained with dispersed mycelia than with pellets, as a result of the high apparent viscosity of the broth, which caused a drop in the power drawn, reducing oil drop break-up. Unexpectedly, bubble sizes observed with dispersed mycelia were smaller than with pellets, a phenomenon which can be explained by the segregation occurring at high biomass concentrations with the dispersed mycelia. Very complex oil drops were produced, containing air bubbles and a high number of structures likely consisting of small water droplets. Bubble location was influenced by biomass morphology. The percentage (in volume) of oil-trapped bubbles increased (from 32 to 80%) as dispersed mycelia concentration increased. A practically constant (32%) percentage of oil-trapped bubbles was observed with pelleted morphology at all biomass concentrations. The results evidenced the high complexity of phases interactions and the importance of mycelial morphology in such processes. PMID:12675561

  2. Spatially varying dispersion to model breakthrough curves.

    PubMed

    Li, Guangquan

    2011-01-01

    Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. PMID:21143474

  3. High-resolution pollutant dispersion modelling in contaminated coastal sites.

    PubMed

    Ramšak, Vanja; Malačič, Vlado; Ličer, Matjaž; Kotnik, Jože; Horvat, Milena; Žagar, Dušan

    2013-08-01

    The recent developments in pollutant measurement methods and techniques necessitate improvements in modelling approaches. The models used so far have been based on seasonally averaged data, which is insufficient for making short-term predictions. We have improved the existing modelling tools for pollutant transport and dispersion on three levels. We significantly refined the numerical grid; we used temporally and spatially non-uniform meteorological parameters for predicting pollutant dispersion and transformation processes; we used grid nesting in order to improve the open boundary condition. We worked on a typical contaminated site (The Gulf of Trieste), where mercury poses a significant environmental threat and where an oil-spill is a realistic possibility. By calculating evasion we improved the mass balance of mercury in the Gulf. We demonstrated that the spreading of river plumes under typical wind conditions is different than has so far been indicated by model simulations. We also simulated an oil-spill in real time. The improved modelling approaches and the upgraded models are now suitable for use with the state-of-the-art measurements technology and can represent an important contribution to the decision-making process. PMID:23477567

  4. The influence of temperature on the lubricating effectiveness of MoS2 dispersed in mineral oils

    NASA Technical Reports Server (NTRS)

    Rolek, R. J.; Cusano, C.; Sliney, H. E.

    1984-01-01

    The effects of oil viscosity, base oil temperature, and surface-active agents naturally present in mineral oils on the lubricating effectiveness of MoS2 dispersions under boundary lubrication conditions are investigated. Friction and wear data are obtained from tests conducted under a wide range of oil viscosities and operating temperatures. The dispersion temperature at which the friction dropped below that obtained with the base oils, depended upon the base oil viscosity and the concentration of surface-active agents present in the oil. White oils showed reductions in friction before mineral oils of like viscosity, and lower viscosity oils showed reductions in friction before heavier viscosity oils. The results show that for a given base oil, wear increases as temperature increases, while the wear obtained from a MoS2 dispersion made from the base oil remains approximately constant as temperature is increased.

  5. The Role and Modeling of Dispersive Stresses

    NASA Astrophysics Data System (ADS)

    Shavit, U.; Moltchanov, S.

    2012-12-01

    Dispersive stresses represent momentum fluxes that are induced by the spatial heterogeneity of flow environments such as forest canopies, river vegetation and coral reefs. When deriving the average momentum equation for such flow environments, these dispersive stresses resemble the Reynolds stresses but instead of correlations of temporal fluctuations they represent correlations of spatial fluctuations. Surprisingly, these stresses are ignored in flow models and very few studies attempted to provide a physical interpretation, let alone a closure model. Typical arguments that justify such modeling are that these stresses are small and negligible; however, recent studies have shown that they may be important. In a recent study we showed that dispersive stresses at the inlet to obstructed region (made of glass cylinders) are larger than the Reynolds stresses and their contribution to the momentum balance is as important as the pressure and the drag forces. In this presentation we will try to explain what they are, provide some intuitive physical interoperation and show that closure models can be developed. Our results are based on highly detailed particle image velocimeter (PIV) measurements that were obtained inside a canopy model made of vertical thin glass plates. Forty nine vertical cross sections were obtained 1000 times generating a huge dataset of more than 250 million data points for each flow conditions. A careful spatial averaging procedure was developed and both temporal and spatial correlations were obtained. An order of magnitude analysis will be presented and the role of each of the terms in the momentum equation will be evaluated. It will be shown that the dispersive stresses are large and significant within the area of the canopy leading edge. Since dispersive stresses do not exist upstream from the canopy they are expected to grow once the flow enters the canopy. Our PIV data shows an initial fast growth up to about one length scale into the patch

  6. Eulerian network modeling of longitudinal dispersion

    NASA Astrophysics Data System (ADS)

    Mehmani, Yashar; Balhoff, Matthew T.

    2015-10-01

    A novel Eulerian network model that incorporates "shear dispersion," the stretching of solute due to nonuniform velocity profiles within pore throats is developed. The superposing transport method (STM) is nonlocal in time (i.e., uses information from several previous time steps) and is equivalent to performing network-wide time convolutions of elementary throat response functions. Predicted macroscopic longitudinal dispersion coefficients for disordered sphere packs are in good agreement with published experimental data. We further investigate the impact of mixing assumptions within pores on macroscopic longitudinal dispersion and find the dependence to be weak for disordered sphere packs. Limitations of Eulerian network models as a whole are also discussed, and their inappropriateness for ordered porous media concluded.

  7. Industrial Source Complex (ISC) dispersion model. Software

    SciTech Connect

    Schewe, G.; Sieurin, E.

    1980-01-01

    The model updates various EPA dispersion model algorithms and combines them in two computer programs that can be used to assess the air quality impact of emissions from the wide variety of source types associated with an industrial source complex. The ISC Model short-term program ISCST, an updated version of the EPA Single Source (CRSTER) Model uses sequential hourly meteorological data to calculate values of average concentration or total dry deposition for time periods of 1, 2, 3, 4, 6, 8, 12 and 24 hours. Additionally, ISCST may be used to calculate 'N' is 366 days. The ISC Model long-term computer program ISCLT, a sector-averaged model that updates and combines basic features of the EPA Air Quality Display Model (AQDM) and the EPA Climatological Dispersion Model (CDM), uses STAR Summaries to calculate seasonal and/or annual average concentration or total deposition values. Both the ISCST and ISCLT programs make the same basic dispersion-model assumptions. Additionally, both the ISCST and ISCLT programs use either a polar or a Cartesian receptor grid...Software Description: The programs are written in the FORTRAN IV programming language for implementation on a UNIVAC 1110 computer and also on medium-to-large IBM or CDC systems. 65,000k words of core storage are required to operate the model.

  8. Practical monitoring of the short-term distribution of dispersed oils

    SciTech Connect

    Railsback, S.F.; Robilliard, G.A.; Mortenson, J.R.

    1987-01-01

    An experimental program for monitoring the short-term distribution and concentration of chemically dispersed oil slicks has been developed for Clean Bay, the San Francisco area oil spill cleanup cooperative. The methods used in the program are experimental and still under development. The objectives of the program are to (1) document the surface area and volume of water affected by dispersed oil, (2) estimate the effectiveness of the dispersant, (3) determine the peak and (4) the range of oil-dispersant concentrations in the affected water. Additional objectives that may be attained if field conditions are acceptable are to: (5) estimate the rate at which oil disperses downward, and (6) estimate what fraction of the light-molecular-weight hydrocarbons are evaporated after application of the dispersant. The program includes oil concentration measurements made with a field fluorimeter and by laboratory analysis. The program is flexibly designed so that it can be adapted to a variety of field conditions. 7 refs., 1 fig.

  9. Intercomparison of atmospheric dispersion models

    NASA Astrophysics Data System (ADS)

    Caputo, Marcelo; Giménez, Marcelo; Schlamp, Miguel

    An intercomparison between Gaussian, Gaussian segmented plumes and Lagrangian codes is presented. The codes chosen for the simulation of a gaseous emission under real meteorological conditions were AERMOD, HPDM, PCCOSYMA and HYSPLIT. The emission source was located at 37.35°N and 78.24°W in a flat terrain. The meteorological data were obtained from RAMS code output. The AERMOD and HPDM meteorological preprocessors results were analyzed. The main differences found are originated in the sensible heat flux (SHTF) and u* (friction velocity) computation, whose values impact directly on the Monin-Obukov length and mixing height calculation. These differences and the strong dependence of the results on them indicate that more development should still be done in order to improve the algorithms for the meteorological variables calculations, mainly during stable conditions. A more realistic description is performed by the segmented Gaussian plume model (PCCOSYMA) respect to the Gaussian ones (AERMOD, HPDM) because it limits the plume length along the wind direction. It also predicts reasonably well the contaminant cloud rotation respect to the Lagrangian code (HYSPLIT) as no major difference between the wind field and the wind at the source location is present in the analyzed case. During the stable hours, HPDM calculates the most stable situation and the lowest mixing heights. Because of this there is a considerable discrepancy in the maximum ground level concentration respect to the other codes. While during the unstable hours HPDM calculates the most unstable situation, nevertheless the maximum ground level concentrations predicted by all the Gaussian and Lagrangian codes are comparable.

  10. Dispersant Corexit 9500A and chemically dispersed crude oil decreases the growth rates of meroplanktonic barnacle nauplii (Amphibalanus improvisus) and tornaria larvae (Schizocardium sp.).

    PubMed

    Almeda, Rodrigo; Bona, Shawn; Foster, Charles R; Buskey, Edward J

    2014-08-01

    Our knowledge of the lethal and sublethal effects of dispersants and dispersed crude oil on meroplanktonic larvae is limited despite the importance of planktonic larval stages in the life cycle of benthic invertebrates. We determined the effects of Light Louisiana Sweet crude oil, dispersant Corexit 9500A, and dispersant-treated crude oil on the survival and growth rates of nauplii of the barnacle Amphibalanus improvisus and tornaria larvae of the enteropneust Schizocardium sp. Growth rates of barnacle nauplii and tornaria larvae were significantly reduced after exposure to chemically dispersed crude oil and dispersant Corexit 9500A at concentrations commonly found in the water column after dispersant application in crude oil spills. We also found that barnacle nauplii ingested dispersed crude oil, which may have important consequences for the biotransfer of petroleum hydrocarbons through coastal pelagic food webs after a crude oil spill. Therefore, application of chemical dispersants increases the impact of crude oil spills on meroplanktonic larvae, which may affect recruitment and population dynamics of marine benthic invertebrates. PMID:25028258

  11. Unexpected Interaction with Dispersed Crude Oil Droplets Drives Severe Toxicity in Atlantic Haddock Embryos

    PubMed Central

    Sørhus, Elin; Edvardsen, Rolf B.; Karlsen, Ørjan; Nordtug, Trond; van der Meeren, Terje; Thorsen, Anders; Harman, Christopher; Jentoft, Sissel; Meier, Sonnich

    2015-01-01

    The toxicity resulting from exposure to oil droplets in marine fish embryos and larvae is still subject for debate. The most detailed studies have investigated the effects of water-dissolved components of crude oil in water accommodated fractions (WAFs) that lack bulk oil droplets. Although exposure to dissolved petroleum compounds alone is sufficient to cause the characteristic developmental toxicity of crude oil, few studies have addressed whether physical interaction with oil micro-droplets are a relevant exposure pathway for open water marine speices. Here we used controlled delivery of mechanically dispersed crude oil to expose pelagic embryos and larvae of a marine teleost, the Atlantic haddock (Melanogrammus aeglefinus). Haddock embryos were exposed continuously to two different concentrations of dispersed crude oil, high and low, or in pulses. By 24 hours of exposure, micro-droplets of oil were observed adhering and accumulating on the chorion, accompanied by highly elevated levels of cyp1a, a biomarker for exposure to aromatic hydrocarbons. Embryos from all treatment groups showed abnormalities representative of crude oil cardiotoxicity at hatch (5 days of exposure), such as pericardial and yolk sac edema. Compared to other species, the frequency and severity of toxic effects was higher than expected for the waterborne PAH concentrations (e.g., 100% of larvae had edema at the low treatment). These findings suggest an enhanced tissue uptake of PAHs and/or other petroleum compounds from attached oil droplets. These studies highlight a novel property of haddock embryos that leads to greater than expected impact from dispersed crude oil. Given the very limited number of marine species tested in similar exposures, the likelihood of other species with similar properties could be high. This unanticipated result therefore has implications for assessing the ecological impacts of oil spills and the use of methods for dispersing oil in the open sea. PMID:25923774

  12. Unexpected interaction with dispersed crude oil droplets drives severe toxicity in Atlantic haddock embryos.

    PubMed

    Sørhus, Elin; Edvardsen, Rolf B; Karlsen, Ørjan; Nordtug, Trond; van der Meeren, Terje; Thorsen, Anders; Harman, Christopher; Jentoft, Sissel; Meier, Sonnich

    2015-01-01

    The toxicity resulting from exposure to oil droplets in marine fish embryos and larvae is still subject for debate. The most detailed studies have investigated the effects of water-dissolved components of crude oil in water accommodated fractions (WAFs) that lack bulk oil droplets. Although exposure to dissolved petroleum compounds alone is sufficient to cause the characteristic developmental toxicity of crude oil, few studies have addressed whether physical interaction with oil micro-droplets are a relevant exposure pathway for open water marine speices. Here we used controlled delivery of mechanically dispersed crude oil to expose pelagic embryos and larvae of a marine teleost, the Atlantic haddock (Melanogrammus aeglefinus). Haddock embryos were exposed continuously to two different concentrations of dispersed crude oil, high and low, or in pulses. By 24 hours of exposure, micro-droplets of oil were observed adhering and accumulating on the chorion, accompanied by highly elevated levels of cyp1a, a biomarker for exposure to aromatic hydrocarbons. Embryos from all treatment groups showed abnormalities representative of crude oil cardiotoxicity at hatch (5 days of exposure), such as pericardial and yolk sac edema. Compared to other species, the frequency and severity of toxic effects was higher than expected for the waterborne PAH concentrations (e.g., 100% of larvae had edema at the low treatment). These findings suggest an enhanced tissue uptake of PAHs and/or other petroleum compounds from attached oil droplets. These studies highlight a novel property of haddock embryos that leads to greater than expected impact from dispersed crude oil. Given the very limited number of marine species tested in similar exposures, the likelihood of other species with similar properties could be high. This unanticipated result therefore has implications for assessing the ecological impacts of oil spills and the use of methods for dispersing oil in the open sea. PMID:25923774

  13. Dispersant Effectiveness Of Heavy Fuel Oils Using The Baffled Flask Test

    EPA Science Inventory

    Dispersants have been widely used as a primary response measure for marine oil spills around the world. Recently, the U.S. Environmental Protection Agency (EPA) developed an improved laboratory dispersant testing protocol, called the Baffled Flask Test (BFT). The BFT protocol w...

  14. Effects of vertical shear in modelling horizontal oceanic dispersion

    NASA Astrophysics Data System (ADS)

    Lanotte, A. S.; Corrado, R.; Palatella, L.; Pizzigalli, C.; Schipa, I.; Santoleri, R.

    2016-02-01

    The effect of vertical shear on the horizontal dispersion properties of passive tracer particles on the continental shelf of the South Mediterranean is investigated by means of observation and model data. In situ current measurements reveal that vertical gradients of horizontal velocities in the upper mixing layer decorrelate quite fast ( ˜ 1 day), whereas an eddy-permitting ocean model, such as the Mediterranean Forecasting System, tends to overestimate such decorrelation time because of finite resolution effects. Horizontal dispersion, simulated by the Mediterranean sea Forecasting System, is mostly affected by: (1) unresolved scale motions, and mesoscale motions that are largely smoothed out at scales close to the grid spacing; (2) poorly resolved time variability in the profiles of the horizontal velocities in the upper layer. For the case study we have analysed, we show that a suitable use of deterministic kinematic parametrizations is helpful to implement realistic statistical features of tracer dispersion in two and three dimensions. The approach here suggested provides a functional tool to control the horizontal spreading of small organisms or substance concentrations, and is thus relevant for marine biology, pollutant dispersion as well as oil spill applications.

  15. The removal of fatty acids from edible oil. Removal of the dispersed phase of a water-in-oil dispersion by a hydrophilic membrane

    SciTech Connect

    Keutrentjes, J.T.F.; Doornbusch, G.I.; Van't Riet, K. )

    1991-01-01

    Fatty acids can be extracted from an oil phase by forming a dispersed phase of saponified fatty acids/water/isopropanol in oil. This dispersion can be separated in the two phases by two membranes of opposite polarity in series. In this study the separation of the water phase from the dispersion by a hydrophilic membrane and the mechanisms underlying the flux characteristics are investigated. The permeation flux through a PAN ultrafiltration membrane is optimized with respect to the fatty acid/water/isopropanol ratio. It appears that a 1:6.5:3 (v/v) ratio gives the highest flux (95/(m{sup 2}{center dot}h{center dot}bar)). The dispersion at these conditions consists of a continuous oil phase as well as a continuous water phase between 20 and 65% water phase hold up. The flux/pressure curve shows a linear increase of the flux with pressure at low pressures (determined buy the membrane resistance), followed by a maximum flux value for the case where the volume of the water phase present in the inflow is limiting. It is not possible to remove the water phase with membranes below a water phase hold up to 20%. At this hold up value the transition between a bicontinuous and a discrete dispersion also occurs.

  16. Debris Dispersion Model Using Java 3D

    NASA Technical Reports Server (NTRS)

    Thirumalainambi, Rajkumar; Bardina, Jorge

    2004-01-01

    This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.

  17. A Method for Converting Aqueous Demetallization Products into Dispersed Metal Oxide Nanocatalysts in Heavy Oil

    NASA Astrophysics Data System (ADS)

    Abdrabo, Amr Abdelrazek Elgeuoshy Meghawry

    Metallic heteroatoms deactivate expensive catalyst and, thus, should be removed at early stages during crude oil processing. Electro and biological demetallization are examples of two emerging techniques which remove the metallic heteroatoms; mainly nickel and vanadium, into ions or ionic complexes ultimately residing in the aqueous phase of a two phase water/oil system. This work investigates the conversion of the aqueous metallic species into metal oxide nanoparticles, which are effective upgrading catalysts, dispersed in the oil phase. The conversion step commenced in-situ within a water-in-oil emulsion structure, and the resultant nanoparticles remain very well dispersed in the heavy oil phase. The product nanoparticles were characterized, after successful collection from the oil phase, using X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-Ray spectroscopy (EDX). Despite the complexity of the heavy oil system, results confirmed the in-situ formation of NiO and V2O5 nanoparticles with mean sizes of 20 and 15 nm, respectively. Some aggregates have, nevertheless, formed, due to the relatively high temperature requirement of the method. Investigating the catalytic role of the as-prepared nanoparticles was limited to the NiO nanoparticles, since only low concentrations of V 2O5 could be prepared. An attempt to increase the concentration of dispersed V2O5 by using precursors with higher solubility in water was not successful. A semi-batch reactor setup was employed to investigate the catalytic hydrocracking of heavy oil in the presence of dispersed NiO nanoparticles. On the other hand, batch reactor arrangement was employed to study the thermalcracking of heavy oil in the presence of dispersed NiO nanoparticles.

  18. Accurate astronomical atmospheric dispersion models in ZEMAX

    NASA Astrophysics Data System (ADS)

    Spanò, P.

    2014-07-01

    ZEMAX provides a standard built-in atmospheric model to simulate atmospheric refraction and dispersion. This model has been compared with other ones to assess its intrinsic accuracy, critical for very demanding application like ADCs for AO-assisted extremely large telescopes. A revised simple model, based on updated published data of the air refractivity, is proposed by using the "Gradient 5" surface of Zemax. At large zenith angles (65 deg), discrepancies up to 100 mas in the differential refraction are expected near the UV atmospheric transmission cutoff. When high-accuracy modeling is required, the latter model should be preferred.

  19. PREDICTIVE MODELS. Enhanced Oil Recovery Model

    SciTech Connect

    Ray, R.M.

    1992-02-26

    PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1 chemical flooding, where soap-like surfactants are injected into the reservoir to wash out the oil; 2 carbon dioxide miscible flooding, where carbon dioxide mixes with the lighter hydrocarbons making the oil easier to displace; 3 in-situ combustion, which uses the heat from burning some of the underground oil to thin the product; 4 polymer flooding, where thick, cohesive material is pumped into a reservoir to push the oil through the underground rock; and 5 steamflood, where pressurized steam is injected underground to thin the oil. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes.

  20. Biotransformation of petroleum hydrocarbons and microbial communities in seawater with oil dispersions and copepod feces.

    PubMed

    Størdal, Ingvild Fladvad; Olsen, Anders Johny; Jenssen, Bjørn Munro; Netzer, Roman; Altin, Dag; Brakstad, Odd Gunnar

    2015-12-30

    To determine biotransformation of components in crude oil dispersions in the presence of feces from marine copepods, dispersed oil was incubated alone, with the addition of clean or oil-containing feces. We hypothesized that the feces would contribute with nutrients to bacteria, and higher concentrations of oil-degrading bacteria, respectively. Presence of clean feces resulted in higher degradation of aromatic oil compounds, but lower degradation of n-alkanes. Presence of oil-containing feces resulted in higher degradation of n-alkanes. The effect of clean feces on aromatic compounds are suggested to be due to higher concentrations of nutrients in the seawater where aromatic degradation takes place, while the lower degradation of n-alkanes are suggested to be due to a preference by bacteria for feces over these compounds. Large aggregates were observed in oil dispersions with clean feces, which may cause sedimentation of un-weathered lipophilic oil compounds towards the seafloor if formed during oil spills. PMID:26494249

  1. Mesoscale constitutive modeling of magnetic dispersions.

    PubMed

    Bhandar, Anand S; Wiest, John M

    2003-01-15

    A constitutive model for dispersions of acicular magnetic particles has been developed by modeling the particles as rigid dumbbells dispersed in a solvent. The effects of Brownian motion, anisotropic hydrodynamic drag, a steric force in the form of the Maier-Saupe potential, and, most importantly, a mean-field magnetic potential are included in the model. The development is similar to previous models for liquid-crystalline polymers. The model predicts multiple orientational states for the dispersion, and this phase behavior is described in terms of an orientational order parameter S and an average alignment parameter J; the latter is introduced because the magnetic particles have distinguishable direction due to polarity. A transition from isotropic to nematic phases at equilibrium is predicted. Multiple nematic phases-both prolate and oblate-are predicted in the presence of steady shear flow and external magnetic field parallel to the flow. The effect of increasing magnetic interparticle interactions and particle concentration is also presented. Comparisons with experimental data for the steady shear viscosity show very good agreement. PMID:16256493

  2. The oil-dispersion bath in anthroposophic medicine – an integrative review

    PubMed Central

    Büssing, Arndt; Cysarz, Dirk; Edelhäuser, Friedrich; Bornhöft, Gudrun; Matthiessen, Peter F; Ostermann, Thomas

    2008-01-01

    Background Anthroposophic medicine offers a variety of treatments, among others the oil-dispersion bath, developed in the 1930s by Werner Junge. Based on the phenomenon that oil and water do not mix and on recommendations of Rudolf Steiner, Junge developed a vortex mechanism which churns water and essential oils into a fine mist. The oil-covered droplets empty into a tub, where the patient immerses for 15–30 minutes. We review the current literature on oil-dispersion baths. Methods The following databases were searched: Medline, Pubmed, Embase, AMED and CAMbase. The search terms were 'oil-dispersion bath' and 'oil bath', and their translations in German and French. An Internet search was also performed using Google Scholar, adding the search terms 'study' and 'case report' to the search terms above. Finally, we asked several experts for gray literature not listed in the above-mentioned databases. We included only articles which met the criterion of a clinical study or case report, and excluded theoretical contributions. Results Among several articles found in books, journals and other publications, we identified 1 prospective clinical study, 3 experimental studies (enrolling healthy individuals), 5 case reports, and 3 field-reports. In almost all cases, the studies described beneficial effects – although the methodological quality of most studies was weak. Main indications were internal/metabolic diseases and psychiatric/neurological disorders. Conclusion Beyond the obvious beneficial effects of warm bathes on the subjective well-being, it remains to be clarified what the unique contribution of the distinct essential oils dispersed in the water can be. There is a lack of clinical studies exploring the efficacy of oil-dispersion baths. Such studies are recommended for the future. PMID:19055811

  3. PREDICTIVE MODELS. Enhanced Oil Recovery Model

    SciTech Connect

    Ray, R.M.

    1992-02-26

    PREDICTIVE MODELS is a collection of five models - CFPM, CO2PM, ICPM, PFPM, and SFPM - used in the 1982-1984 National Petroleum Council study of enhanced oil recovery (EOR) potential. Each pertains to a specific EOR process designed to squeeze additional oil from aging or spent oil fields. The processes are: 1 chemical flooding; 2 carbon dioxide miscible flooding; 3 in-situ combustion; 4 polymer flooding; and 5 steamflood. CFPM, the Chemical Flood Predictive Model, models micellar (surfactant)-polymer floods in reservoirs, which have been previously waterflooded to residual oil saturation. Thus, only true tertiary floods are considered. An option allows a rough estimate of oil recovery by caustic or caustic-polymer processes. CO2PM, the Carbon Dioxide miscible flooding Predictive Model, is applicable to both secondary (mobile oil) and tertiary (residual oil) floods, and to either continuous CO2 injection or water-alternating gas processes. ICPM, the In-situ Combustion Predictive Model, computes the recovery and profitability of an in-situ combustion project from generalized performance predictive algorithms. PFPM, the Polymer Flood Predictive Model, is switch-selectable for either polymer or waterflooding, and an option allows the calculation of the incremental oil recovery and economics of polymer relative to waterflooding. SFPM, the Steamflood Predictive Model, is applicable to the steam drive process, but not to cyclic steam injection (steam soak) processes. The IBM PC/AT version includes a plotting capability to produces a graphic picture of the predictive model results.

  4. Modeling of Building Scale Flow and Dispersion

    SciTech Connect

    Lee, R L; Calhoun, R J; Chan, S T; Leone, J; Stevens, D E

    2001-07-10

    Predictions of airflows around buildings and the associated thermal and dispersion phenomena continue to be challenging because of the presence of extremely heterogeneous surface structures within urban areas. Atmospheric conditions can induce local winds to flow around structures rather than over them. Thus pollutants that are released at or near the ground tend to persist at relatively low levels with only minimal ventilation of the airborne material away from the ground surface. While flow and dispersion phenomena can be studied within wind tunnel settings, recent advances in numerical modeling have enabled computational fluid dynamics (CFD) to evolve into an important tool in the simulation of building scale flows. They are developing numerical models to simulate the flow and dispersion of releases around multi-building complexes. These models will be used to assess the transport and fate of releases of hazardous agents within urban areas and to support emergency response activities. There are already a number of models that have been developed to simulate flow and dispersion around urban settings. A recent collection of these papers can be found in the Proceedings of the International Workshop on CFD for Wind Climate in Cities. Most of the simulation studies presented in the literature are based on single buildings with a few of these results compared with wind tunnel experiments. As the applications become more advanced, the influence of multiple buildings, vegetation, surface heating and atmospheric stability on flow and dispersion has begun to be incorporated into recent CFD models. The focus of this paper is to describe LLNL's effort in the development of a high-performance CFD model for simulating transport and diffusion of hazardous releases around buildings and building complexes. A number of new physics features have been implemented in order to customize the CFD model for the urban application. These include surface heating, vegetation canopy, heat

  5. Recent improvements in optimizing use of dispersants as a cost-effective oil spill countermeasure technique

    SciTech Connect

    Daling, P.S.; Indrebo, G.

    1996-12-31

    Several oil spill incidents during recent years have demonstrated that the physico-chemical properties of spilled oil and the effectiveness of available combat methods are, in addition to the prevailing environmental and weather conditions, key factors that determine the consequences of an oil spill. Pre-spill analyses of the feasibility and effectiveness of different response strategies, such as mechanical recovery and dispersants, for actual oils under various environmental conditions should therefore be an essential part of any oil spill contingency planning to optimize the overall {open_quotes}Net Environmental Benefit{close_quotes} of a combat operation. During the four-year research program ESCOST ({open_quotes}ESSO-SINTEF Coastal Oil Spill Treatment Program{close_quotes}), significant improvements have been made in oil spill combat methods and in tools for use in contingency planning and decision-making during oil spill operations. This paper will present an overview of the main findings obtained with respect to oil weathering and oil spill dispersant treatment.

  6. Synergistic effect of crude oil plus dispersant on bacterial community in a louisiana salt marsh sediment.

    PubMed

    Al-Jawasim, Mohammed; Yu, Kewei; Park, Joong-Wook

    2015-09-01

    A combined effect of crude oil plus dispersant (Corexit 9500A) significantly altered indigenous bacterial communities in a Louisiana salt marsh sediment after 30 days of incubation; the crude oil and/or Corexit 9500A treatments triggered shifts in bacterial communities and the shifted bacterial structure by crude oil plus Corexit 9500A was considerably different from those by either crude oil or Corexit 9500A. However, the synergistic effect of crude oil plus Corexit 9500A was not observed after 7 days of incubation; the bacterial community was slightly shifted by Corexit 9500A and the crude oil did not trigger any bacterial community shift after 7 days of incubation. DNA sequencing data indicated that Chromobacterium species was enriched in the Corexit 9500A microcosms after 7 days of incubation, while Pseudomonas, Advenella, Acidocella and Dyella spp. were enriched after 30 days of incubation. Parvibaculum was a dominant species in the crude oil microcosms after 30 days of incubation. Rhodanobacter, Dyella and Frateuria spp. were dominant in crude oil plus Corexit 9500A microcosms after 30 days of incubation. Our data show that the effect of crude oil plus Corexit 9500A on bacterial community is synergistic, and thus the dispersant effect should be considered with the spilled oil to correctly evaluate the environmental impact. PMID:26316543

  7. Multiscale analysis of compartment models with dispersal

    PubMed Central

    Kang, Yun; Castillo-Chavez, Carlos

    2014-01-01

    Dispersal, minimally defined as the movement or spatial displacement of organisms, links the dynamics of local population within and across regions. Landscape-population interactions responsible for driving co-evolutionary processes that on the long run shape communities of organisms, determine the outcomes of biological invasions, or alter the dynamics and evolution of infectious agents, are connected via dispersal. A generalized modeling framework is introduced derived from our interests in characterizing the dynamics of animal populations and trade in the presence of disease. We explore the impact of dispersal on systems that include disease, Allee effects, and host mobility. The emphasis is on disease, a selective force, that often plays a fundamental role on the life-history dynamics of a population. The models incorporate disease-driven effects on, often excluded, interactions like individual’s competitive ability to acquire resources. The framework makes use of deterministic and stochastic models that account for features often ignored or rarely included like (a) induced Allee effects; (b) disease dynamics; and (c) spatial heterogeneity. Preliminary results highlight the role of initial conditions, patch quality, and “topological” or connectivity landscape structure (the physical space where individuals move, reproduce, get sick, die, or compete for resources) on the dynamics of populations when disease is an important selective force. We dedicate this article to our grand mentor Simon Levin. PMID:22934939

  8. The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment.

    PubMed

    Haule, Kamila; Freda, Włodzimierz

    2016-04-01

    Oil pollution in seawater, primarily visible on sea surface, becomes dispersed as an effect of wave mixing as well as chemical dispersant treatment, and forms spherical oil droplets. In this study, we examined the influence of oil droplet size of highly dispersed Petrobaltic crude on the underwater visible light flux and the inherent optical properties (IOPs) of seawater, including absorption, scattering, backscattering and attenuation coefficients. On the basis of measured data and Mie theory, we calculated the IOPs of dispersed Petrobaltic crude oil in constant concentration, but different log-normal size distributions. We also performed a radiative transfer analysis, in order to evaluate the influence on the downwelling irradiance Ed, remote sensing reflectance Rrs and diffuse reflectance R, using in situ data from the Baltic Sea. We found that during dispersion, there occurs a boundary size distribution characterized by a peak diameter d0  = 0.3 μm causing a maximum E d increase of 40% within 0.5-m depth, and the maximum Ed decrease of 100% at depths below 5 m. Moreover, we showed that the impact of size distribution on the "blue to green" ratios of Rrs and R varies from 24% increase to 27% decrease at the same crude oil concentration. PMID:26635218

  9. Air modeling: Air dispersion models; regulatory applications and technological advances

    SciTech Connect

    Miller, M.; Liles, R.

    1995-09-01

    Air dispersion models are a useful and practical tool for both industry and regulatory agencies. They serve as tools for engineering, permitting, and regulations development. Their cost effectiveness and ease of implementation compared to ambient monitoring is perhaps their most-appealing trait. Based on the current momentum within the U.S. EPA to develop better models and contain regulatory burdens on industry, it is likely that air dispersion modeling will be a major player in future air regulatory initiatives.

  10. Large eddy simulation and K-profile parameterization of submesoscale oil droplet plume dispersion in Langmuir turbulence

    NASA Astrophysics Data System (ADS)

    Yang, D.; Chen, B.; Chamecki, M.; Meneveau, C. V.

    2014-12-01

    As the oil plumes from deep water blowouts reach the ocean mixed layer (OML), their near-surface dispersions are highly influenced by the wind and wave-generated submesoscale Langmuir turbulence in the OML. In this study, we use large eddy simulations (LES) to model the oil dispersion at scales < 1 km. We find that despite the complex patterns of the instantaneous surface oil slick, the time-averaged surface oil plume can be parameterized as a Gaussian-type plume. The mean surface plume grows linearly downstream, with the centerline inclined clockwise (in the Northern Hemisphere) with respect to the wind and wave direction due to the Ekman transport. The inclination angle increase as the droplet size decreases, while the plume growth rate varies non-monotonically with oil droplet size. Using LES data, we evaluate the eddy viscosity and diffusivity following the K-profile parameterization (KPP) framework. We also evaluate the stress-strain misalignments caused by Stokes drift and the enhancement of eddy viscosity and diffusivity caused by Langmuir circulations. Improvements to the KPP model will be discussed. This study is supported by a Gulf of Mexico Research Initiative research grant.

  11. A test for evaluating the toxicity of oils, dispersants, and oil biodegradation products to embryos of grass shrimp (Palaemonetes pugio)

    SciTech Connect

    Foss, S.S.; Fisher, W.S.; Chapman, P.J.; Shelton, M.

    1994-12-31

    A test has been developed to determine the toxicity of oil, commercial oil dispersants, and oil biodegradation products to embryos of the grass shrimp, Palaemonetes pugio. The system has several advantages over traditional toxicity tests: Embryos are exposed separately in glass tubes eliminating interaction between individuals, they do not require feeding, are easily examined, and require low volumes of test toxicant. Additionally, tests can be performed using artificial sea salts and adult P. pugio can be maintained and cultured year round in the laboratory. Toxicity tests demonstrated that oil dispersants increased the toxicity of the water-soluble fraction of No. 2 Fuel Oil with estimated LC50 values approximating those obtained with the 7d chronic tests using Mysidopsis bahia. Embryos exposed to neutral fractions derived by microbial degradation of weathered Prudhoe Bay crude oil showed toxicity of metabolic products at relatively low concentrations and cause virtually 100% mortality within a narrow time interval. P. pugio embryos were especially responsive to oil metabolites, exhibiting high sensitivity and low variability. All tests showed a consistently high survival (90--100%) of control embryos to hatch under a variety of temperatures and salinities; embryos at any given test condition usually hatched within 24h of one another.

  12. Performance Evaluation of Dense Gas Dispersion Models.

    NASA Astrophysics Data System (ADS)

    Touma, Jawad S.; Cox, William M.; Thistle, Harold; Zapert, James G.

    1995-03-01

    This paper summarizes the results of a study to evaluate the performance of seven dense gas dispersion models using data from three field experiments. Two models (DEGADIS and SLAB) are in the public domain and the other five (AIRTOX, CHARM, FOCUS, SAFEMODE, and TRACE) are proprietary. The field data used are the Desert Tortoise pressurized ammonia releases, Burro liquefied natural gas spill tests, and the Goldfish anhydrous hydrofluoric acid spill experiments. Desert Tortoise and Goldfish releases were simulated as horizontal jet releases, and Burro as a liquid pool. Performance statistics were used to compare maximum observed concentrations and plume half-width to those predicted by each model. Model performance varied and no model exhibited consistently good performance across all three databases. However, when combined across the three databases, all models performed within a factor of 2. Problems encountered are discussed in order to help future investigators.

  13. Convective boundary layer and modeling of dispersion

    NASA Astrophysics Data System (ADS)

    Ahmed, Nizam Uddin

    Looping, bifurcation, and meandering of a plume are generally observed in a convective field. The blobby or puffy concentration patterns associated with these plumes are marked deviations from what is expected from either conventional K-theory or Gaussian distribution formulae. A numerical model was developed for material dispersion in a convective boundary layer from both elevated and ground sources. Mechanistic formulation, rather than parameterization, or statistical behavior of planetary boundary layer (PBL) phenomena, was used as a basis. The dispersion mechanism is considered to be due to mixing between the updraft and the downdraft. This model uses two universal constants, (turbulent entrainment constant, a, and decay constant A) and a mixing scheme directly supported by observations. Researchers examined the dispersion pattern from the elevated and ground sources. For elevated sources, the maximum concentration descends first to the ground level at some distance downwind, and then rises, depending on the inversion height, the mean wind and height at which material is released. The updrafts have a higher velocity than the downdrafts and consequently the downdrafts occupy a larger horizontal area. In some cases the updrafts and downdrafts are comparable and materials are caught equally in the updrafts and downdrafts. The concentration of materials is split into two parts, one moving downward and the other upward. It is shown using the same mechanistic principles, that different convective situations cause different concentration patterns (for example, looping, bifurcating of a plume, and ascending of center line).

  14. The comparative fate of chemically dispersed and untreated oils in an Arctic nearshore environment

    SciTech Connect

    Boehm, P.D.

    1982-10-01

    The distribution and environmental fate of petroleum hydrocarbons introduced into the nearshore environment of Cape Hatt, Baffin Island, Canada, during two controlled experimental discharges of a Venezuelan (Lagomedio) crude oil have been studied. An analytical program based on a combination of ultraviolet/fluorescence studies, high resolution gas chromatography, and computer-assisted gas chromatographic mass spectrometry has been used to examine several hundred oil, seawater, sediment, sediment trap, surface floc, and benthic animal (seven species) samples to determine the distribution, transport, and weathering of oil spilled in two scenarios: as untreated oil on the surface and as chemically dispersed oil discharged below the surface. Conclusions are drawn about the weathering of oil in the two scenarios, transport of low and high molecular weight hydrocarbons into the water column and their persistence, the sedimentation of oil, the incorporation of oil into the sediment via sedimentation onto the surface floc and direct penetration of the sediment/ water interface, and the uptake and depuration of untreated and chemically dispersed oils by seven species of filter feeders and deposit feeders in the subtidal benthos.

  15. UPTAKE AND EFFECTS OF DISPERSED OIL DROPLETS AND EMULSIFIED OIL BY ESTUARINE CRUSTACEANS IN THE GULF OF MEXICO

    EPA Science Inventory

    The results from this project will provide information on the extent of uptake of dispersed petroleum from the seawater and uptake of emulsified oil from the sediment by blue crabs and grass shrimp of different life history stages. The primary focus of the study will be eff...

  16. Modeling pollutant dispersion within a tornadic thunderstorm

    SciTech Connect

    Pepper, D.W.

    1981-01-01

    A three-dimensional numerical model was developed to calculate ground-level air concentration and deposition of particles entrained in a tornadic thunderstorm. The rotational characteristics of the tornadic storm are within the larger mesoscale flow of the storm system and transported with the vortex. Turbulence exchange coefficients are based on empirical values. The quasi-Lagrangian method of moments is used to model the transport of concentration within a grid cell volume. Results indicate that updrafts and downdrafts, coupled with scavenging of particles by precipitation, account for most of the material being deposited closer to the site than anticipated. Approximately 5% of the pollutant is dispersed into the stratosphere.

  17. Ocean experiments and remotely sensed images of chemically dispersed oil spills

    NASA Technical Reports Server (NTRS)

    Croswell, W. F.; Fedors, J. C.; Hoge, F. E.; Swift, R. N.; Johnson, J. C.

    1983-01-01

    A series of experiments was performed at sea where the effectiveness of dispersants applied from a helicopter was tested on fresh and weathered crude oils released from a surface research vessel. In conjunction with these experiments, remote sensing measurements using an array of airborne optical and microwave sensors were performed in order to aid in the interpretation of the dispersant effectiveness and to obtain quantitative images of oil on the sea under controlled conditions. Surface oil thickness and volume are inferred from airborne measurements using a dual-channel microwave imaging radiometer, aerial color photography, and an airborne oceanographic lidar. The remotely sensed measurements are compared with point sampled data obtained using a research vessel. The mass balance computations of surface versus subsurface oil volume using remotely sensed and point sampled data are consistent with each other and with the volumes of oil released. Data collected by the several techniques concur in indicating that, for the oils used and under the sea conditions encountered, the dispersant and application method are primarily useful when applied to fresh oil.

  18. Dispersion of Louisiana crude oil in salt water environment by Corexit 9500A in the presence of natural coastal materials

    NASA Astrophysics Data System (ADS)

    Tansel, Berrin; Lee, Mengshan; Berbakov, Jillian; Tansel, Derya Z.; Koklonis, Urpiana

    2014-04-01

    Effectiveness of Corexit 9500A for dispersing Louisiana crude oil was evaluated in salt water solutions containing natural materials in relation to salinity and dispersant-to-oil ratio (DOR). Experimental results showed that both salinity and DOR had significant effects on dispersion of Louisiana crude oil in the presence of different natural materials. The natural materials added to the salt water solutions included sea sand (South Beach, Miami, Florida), red mangrove leaves (Rhizophora mangle), seaweed (Sargassum natans), and sea grass (Halodule wrightii). Dispersant effectiveness (amount of oil dispersed into the water) was reduced significantly with increasing salinity with the minimum effectiveness observed in the salinity range between 30 and 50 ppt in all aqueous samples containing natural materials. When significant amounts of floating oil were present, the partially submerged natural materials enhanced the transfer of oil into the water column, which improved the dispersion effectiveness. However, dispersant effectiveness was significantly reduced when the amount of floating oil was relatively small and could not be released back to the water column. Surface tension may not be an adequate parameter for monitoring the effectiveness of dispersants in salt water environment. When distilled water was used (i.e., zero salinity), surface tension was significantly reduced with increasing dispersant concentration. However, there was no clear trend in the surface tension of the salt water solutions (17-51 ppt) containing crude oil and natural materials with increasing dispersant concentration.

  19. Oil spill dispersants induce formation of marine snow by phytoplankton-associated bacteria.

    PubMed

    van Eenennaam, Justine S; Wei, Yuzhu; Grolle, Katja C F; Foekema, Edwin M; Murk, AlberTinka J

    2016-03-15

    Unusually large amounts of marine snow, including Extracellular Polymeric Substances (EPS), were formed during the 2010 Deepwater Horizon oil spill. The marine snow settled with oil and clay minerals as an oily sludge layer on the deep sea floor. This study tested the hypothesis that the unprecedented amount of chemical dispersants applied during high phytoplankton densities in the Gulf of Mexico induced high EPS formation. Two marine phytoplankton species (Dunaliella tertiolecta and Phaeodactylum tricornutum) produced EPS within days when exposed to the dispersant Corexit 9500. Phytoplankton-associated bacteria were shown to be responsible for the formation. The EPS consisted of proteins and to lesser extent polysaccharides. This study reveals an unexpected consequence of the presence of phytoplankton. This emphasizes the need to test the action of dispersants under realistic field conditions, which may seriously alter the fate of oil in the environment via increased marine snow formation. PMID:26781957

  20. OIL SPILL DISPERSANT EFFECTIVENESS PROTOCOL. I: IMPACT OF OPERATIONAL VARIABLES

    EPA Science Inventory

    The current U.S. Environmental Protection Agency protocol for testing the effectiveness of dispersants, the swirling flask test, has been found to give widely varying results in the hands of different testing laboratories. The sources of the ambiguities in the test were determin...

  1. Effect of the dispersion of oil in freshwater based on time-dependent Daphnia magna toxicity tests

    SciTech Connect

    Vindimian, E.; Vollat, B.; Garric, J. )

    1992-02-01

    The purpose of this work is the study of the time dependence of the acute toxicity of oil and dispersants on a sensitive freshwater organism: Daphnia magna. Two different oils were used: a crude oil from the southwest of France and a gas oil free from volatile substances after being equilibrated with atmosphere. Two commercial dispersants were used: British Petroleum Enersperse 1037 and Dasic Freshwater for this study.

  2. Photochemical fate of solvent constituents of Corexit oil dispersants.

    PubMed

    Kover, Stephanie C; Rosario-Ortiz, Fernando L; Linden, Karl G

    2014-04-01

    In 2010, an estimated 1.87 million gallons (7079 cubic meters) of chemical dispersants were applied to open ocean waters in the Gulf of Mexico as part of the response to the Deepwater Horizon blowout. This unprecedented volume of dispersant application highlighted the importance of dispersant chemical formulations, raising questions of dispersant fate and transport in the open ocean and spurring research into formulation improvements. The research presented here elucidates the contribution of photolytic processes to the degradation of two solvent constituents of these dispersant mixtures: propylene glycol (PG) and 2-butoxyethanol (2-BE). A series of photodegradation experiments were conducted to determine the contribution of direct photolysis and indirect photolysis via hydroxyl radical (HO) to compound degradation. Experiments were performed using both deep UV light sources (low pressure (LP) and medium pressure (MP) mercury vapor ultraviolet (UV) lamps) and a solar simulator. Sample matrices included ultrapure water, nitrate amended water, hydrogen peroxide (H2O2) spiked water, Gulf of Mexico seawater, and a surface water from Boulder, CO. Experiments included determination of the molar absorption coefficients (ε) and the HO reaction rate constants (kHO) of the individual compounds. Data illustrated that significant direct photolysis of either PG or 2-BE from sunlight is unlikely. The kHO for PG and 2-BE were determined to be 6.15 × 10(8) M(-1) s(-1) and 1.15 × 10(9) M(-1) s(-1), respectively. Solar simulation and UV experiments indicate that in natural systems, neither PG nor 2-BE is expected to undergo significant, rapid degradation due to direct or indirect photolysis. PG and 2-BE are effectively degraded through indirect photolysis in the presence of high HO concentrations, suggesting UV/H2O2 is a feasible possibility for the treatment of waters containing PG and 2-BE. PMID:24463172

  3. Urban dispersion : challenges for fast response modeling

    SciTech Connect

    Brown, M. J.

    2004-01-01

    There is renewed interest in urban dispersion modeling due to the need for tools that can be used for responding to, planning for, and assessing the consequences of an airborne release of toxic materials. Although not an everyday phenomenon, releases of hazardous gases and aerosols have occurred in populated urban environments and are potentially threatening to human life. These releases may stem from on-site accidents as in the case of industrial chemical releases, may result during transport of hazardous chemicals as in tanker truck or railroad spills, or may be premeditated as in a chemical, biological, or radiological (CBR) agent terrorist attack. Transport and dispersion in urban environments is extremely complicated. Buildings alter the flow fields and deflect the wind, causing updrafts and downdrafts, channeling between buildings, areas of calm winds adjacent to strong winds, and horizontally and vertically rotating-eddies between buildings, at street corners, and other places within the urban canopy (see review by Hosker, 1984). Trees, moving vehicles, and exhaust vents among other things further complicate matters. The distance over which chemical, biological, or radiological releases can be harmful varies from tens of meters to many kilometers depending on the amount released, the toxicity of the agent, and the atmospheric conditions. As we will show later, accounting for the impacts of buildings on the transport and dispersion is crucial in estimating the travel direction, the areal extent, and the toxicity levels of the contaminant plume, and ultimately for calculating exposures to the population.

  4. Antimicrobial activity of clove oil dispersed in a concentrated sugar solution.

    PubMed

    Briozzo, J; Núñez, L; Chirife, J; Herszage, L; D'Aquino, M

    1989-01-01

    Essential oil of clove, dispersed (0.4% v/v) in a concentrated sugar solution, had a marked germicidal effect against various bacteria and Candida albicans. Staphylococcus aureus (five strains), Klebsiella pneumoniae, Pseudomonas aeruginosa, Clostridium perfringens, and Escherichia coli inoculated at a level of 10(7) cfu/ml, and C. albicans (inoculum 4.0 x 10(5) cfu/ml) were killed (greater than 99.999%) after 2-7 min in a laboratory broth supplemented with 63% (v/w) of sugar, and containing 0.4% (v/w) of essential oil of clove. Added organic matter (i.e. human or bovine serum) did not impair its antimicrobial activity. Sugar was not necessary for the antimicrobial activity of clove oil, but the concentrated sugar solution provided a good vehicle for obtaining an oil dispersion that is relatively stable for certain practical applications. PMID:2542213

  5. A role for analytical chemistry in advancing our understanding of the occurrence, fate, and effects of Corexit Oil Dispersants

    USGS Publications Warehouse

    Place, Ben; Anderson, Brian; Mekebri, Abdou; Furlong, Edward T.; Gray, James L.; Tjeerdema, Ron; Field, Jennifer

    2010-01-01

    On April 24, 2010, the sinking of the Deepwater Horizon oil rig resulted in the release of oil into the Gulf of Mexico. As of July 19, 2010, the federal government's Deepwater Horizon Incident Joint Information Center estimates the cumulative range of oil released is 3,067,000 to 5,258,000 barrels, with a relief well to be completed in early August. By comparison, the Exxon Valdez oil spill released a total of 260,000 barrels of crude oil into the environment. As of June 9, BP has used over 1 million gallons of Corexit oil dispersants to solubilize oil and help prevent the development of a surface oil slick. Oil dispersants are mixtures containing solvents and surfactants that can exhibit toxicity toward aquatic life and may enhance the toxicity of components of weathered crude oil. Detailed knowledge of the composition of both Corexit formulations and other dispersants applied in the Gulf will facilitate comprehensive monitoring programs for determining the occurrence, fate, and biological effects of the dispersant chemicals. The lack of information on the potential impacts of oil dispersants has caught industry, federal, and state officials off guard. Until compositions of Corexit 9500 and 9527 were released by the U.S. Environmental Protection Agency online, the only information available consisted of Material Safety Data Sheets (MSDS), patent documentation, and a National Research Council report on oil dispersants. Several trade and common names are used for the components of the Corexits. For example, Tween 80 and Tween 85 are oligomeric mixtures.

  6. A field experiment to assess impact of chemically dispersed oil on Arabian Gulf corals

    SciTech Connect

    Le Gore, R.S.; Cuddeback, J.E.; Hofmann, J.E.; Marszalek, D.S.

    1983-03-01

    Field experiments were conducted on a coral reef at Jurayd Island (Saudi Arabia) in the Arabian Gulf to study the effects of chemically dispersed oil on local corals. Portions of the reef were exposed to predetermined concentrations of oil alone, dispersant alone, and oil-plus-dispersant mixtures. Areas of the reef not exposed to any of the toxicants were used as controls. Arabian Light Crude and Corexit 9527 dispersant were the test toxicants. Two series of experiments were conducted beginning in September 1981, one with a 24-hour exposure period and the other with a 5-day (120-hour) exposure period. Corals were stained for growth rate studies and extensively photographed to document any observed effects. Corals were examined for biological impacts immediately after the exposures, and then at 3-month intervals for 1 year. Water temperature, salinity, dissolved oxygen, and hydrocarbon content were recorded during the exposure periods. Coral growth appeared unaffected by exposure to the toxicants. Some Acropora species corals exposed to dispersed oil for 5 days exhibited delayed effects, which became apparent during the relatively cold winter season.

  7. Biological effects of mechanically and chemically dispersed oil on the Icelandic scallop (Chlamys islandica).

    PubMed

    Frantzen, Marianne; Regoli, Francesco; Ambrose, William G; Nahrgang, Jasmine; Geraudie, Perrine; Benedetti, Maura; Locke, William L; Camus, Lionel

    2016-05-01

    This study aimed to simulate conditions in which dispersant (Dasic NS) might be used to combat an oil spill in coastal sub-Arctic water of limited depth and water exchange in order to produce input data for Net Environmental Benefit Analysis (NEBA) of Arctic and sub-Arctic coastal areas. Concentration dependent differences in acute responses and long-term effects of a 48h acute exposure to dispersed oil, with and without the application of a chemical dispersant, were assessed on the Arctic filter feeding bivalve Chlamys islandica. Icelandic scallops were exposed for 48h to a range of spiked concentrations of mechanically and chemically dispersed oil. Short-term effects were assessed in terms of lysosomal membrane stability, superoxide dismutase, catalase, gluthatione S-transferases, glutathione peroxidases, glutathione reductase, glutathione, total oxyradical scavenging capacity, lipid peroxidation and peroxisomal proliferation. Post-exposure survival, growth and reproductive investment were followed for 2 months to evaluate any long-term consequence. Generally, similar effects were observed in scallops exposed to mechanically and chemically dispersed oil. Limited short-term effects were observed after 48h, suggesting that a different timing would be required for measuring the possible onset of such effects. There was a concentration dependent increase in cumulative post-exposure mortality, but long-term effects on gonadosomatic index, somatic growth/condition factor did not differ among treatments. PMID:26809079

  8. A surface tension based method for measuring oil dispersant concentration in seawater.

    PubMed

    Cai, Zhengqing; Gong, Yanyan; Liu, Wen; Fu, Jie; O'Reilly, S E; Hao, Xiaodi; Zhao, Dongye

    2016-08-15

    This work developed a new method to determine concentration of Corexit EC9500A, and likely other oil dispersants, in seawater. Based on the principle that oil dispersants decrease surface tension, a linear correlation was established between the dispersant concentration and surface tension. Thus, the dispersant concentration can be determined by measuring surface tension. The method can accurately analyze Corexit EC9500A in the concentration range of 0.5-23.5mg/L. Minor changes in solution salinity (<0.3%), pH (7.9-9.0), and dissolved organic matter (<2.0mg/L as TOC) had negligible effects on the measurements. Moreover, effects of extracts from marine sediments were negligible, and thus, the method may be directly applied to seawater-sediment systems. The method accuracy was confirmed by comparing with direct TOC analysis. This simple, fast, economical method offers a convenient analytical tool for quantifying complex oil dispersants in water/seawater, which has been desired by the oil spill research community and industries. PMID:27321800

  9. Immune function in the Arctic Scallop, Chlamys islandica, following dispersed oil exposure.

    PubMed

    Hannam, Marie L; Bamber, Shaw D; Moody, John A; Galloway, Tamara S; Jones, Malcolm B

    2009-05-01

    With the current expansion of offshore oil activities in Arctic regions, there is an urgent need to establish the potential effects of oil-related compounds on Arctic organisms. As susceptibility to growth, disease and survival is determined partly by the condition of an organism's immune system, measurement of endpoints linked to the latter system provide important early warning signals of the sub-lethal effects of exposure to contaminants. This study assessed the impact of dispersed oil exposure on immune endpoints in the Arctic Scallop Chlamys islandica, using a combination of cellular and humoral biological responses. Laboratory exposures of C. islandica to sub-lethal dispersed oil concentrations (0.06 and 0.25 mg l(-1)) were conducted over 15 days, followed by a 7-day recovery period in clean, filtered seawater. Cellular endpoints were significantly altered following dispersed oil exposure: haemocyte counts (P<0.01) and protein levels (P<0.01) were significantly elevated, whilst cell membrane stability (P<0.001) and phagocytosis (P<0.01) demonstrated a significant reduction. Whilst these results indicate alteration in the immune endpoints measured, this appears to be reversible upon removal of the contaminant stress. However, the impact of long-term continuous exposure and high-level acute exposure to oil is still unknown, and may have consequences for disease resistance and hence survival. PMID:19249111

  10. Effectiveness of oil spill dispersants at low salinities and low water temperatures

    SciTech Connect

    Lehtinen, C.M.; Vesala, V-A

    1982-10-01

    The effect of ambient low salinity and low temperature in the Baltic Sea on the effectiveness of dispersants was investigated in the laboratory using a MackayNadeau-Steelman apparatus. Three dispersants were tested on two oils (fresh and weathered crude) at different water temperatures (4, 12, and 15/sup 0/C) and different salinities (3, 7, and 12/sup 0//infinity). The results show a strong dependency on water temperature for all the dispersants tested, although one chemical was less sensitive than the others in this respect. The dispersants showed significant differences between their sensitivity to changes in salinity and in the relationships between effectiveness and dosage. The stability of the dispersion obtained seems to be influenced by both type of oil and water temperature, and some difference between the chemicals could be found also in this respect. The parameters studied strongly affected the performance of the dispersants. It is therefore essential to make a careful choice of dispersants for use in low salinity environments such as the Baltic Sea.

  11. Longitudinal dispersion modeling in small streams

    NASA Astrophysics Data System (ADS)

    Pekarova, Pavla; Pekar, Jan; Miklanek, Pavol

    2014-05-01

    The environmental problems caused by the increasing of pollutant loads discharged into natural water bodies are very complex. For that reason the cognition of transport mechanism and mixing characteristics in natural streams is very important. The mathematical and numerical models have become very useful tools for solving the water management problems. The mathematical simulations based on numerical models of pollution mixing in streams can be used (for example) for prediction of spreading of accidental contaminant waves in rivers. The paper deals with the estimation of the longitudinal dispersion coefficients and with the numerical simulation of transport and transformation of accidental pollution in the small natural streams. There are different ways of solving problems of pollution spreading in open channels, in natural rivers. One of them is the hydrodynamic approach, which endeavours to understand and quantify the spreading phenomenon in a stream. The hydrodynamic models are based on advection-diffusion equation and the majority of them are one-dimensional models. Their disadvantage is inability to simulate the spread of pollution until complete dispersion of pollutant across the stream section is finished. Two-dimensional mixing models do not suffer from these limitations. On the other hand, the one-dimensional models are simpler than two-dimensional ones, they need not so much input data and they are often swifter. Three-dimensional models under conditions of natural streams are applicable with difficulties (or inapplicable) for their complexity and demands on accuracy and amount of input data. As there was mentioned above the two-dimensional models can be used also until complete dispersion of pollutant across the stream section is not finished, so we decided to apply the two-dimensional model SIRENIE. Experimental microbasin Rybarik is the part of the experimental Mostenik brook basin of IH SAS Bratislava. It was established as a Field Hydrological

  12. Effectiveness of the Surfactant Dioctyl Sodium Sulfosuccinate (DOSS) to Disperse Oil in a Changing Marine Environment

    NASA Astrophysics Data System (ADS)

    Steffy, D. A.; Nichols, A.; Kiplagat, G.

    2011-12-01

    We investigated the surfactant which was used to disperse the oil spill which occurred in the Gulf of Mexico during the summer 2010. The surfactant DOSS is an organic sulfonic acid salt which is a synthetic detergent that disrupts the interfacial tension between the saltwater and crude oil phases. The disruption becomes maximum at or above the critical micelle concentration (CMC). The CMC for the surfactant was determined to be at 0.13 % solution in deionized water at a pH of 7.2 and a temperature of 70oF. The CMC is lower at 0.09% solution in salt water. The effect has been identified as a "salting out" effect (Somasundaran, 2006). The CMC of DOSS in both saline and deionized water occurred at lower percent solutions at higher temperatures. The surface tension versus % solution plots are modeled by a power equation, with correlation coefficients consistently over 0.94. Surface tension versus percent solution plots are scalable to fit a temperature desired by the function f(x)= (1/(1+X^α)), where α = T1/T2.

  13. Dispersal kernel estimation: A comparison of empirical and modelled particle dispersion in a coastal marine system

    NASA Astrophysics Data System (ADS)

    Hrycik, Janelle M.; Chassé, Joël; Ruddick, Barry R.; Taggart, Christopher T.

    2013-11-01

    Early life-stage dispersal influences recruitment and is of significance in explaining the distribution and connectivity of marine species. Motivations for quantifying dispersal range from biodiversity conservation to the design of marine reserves and the mitigation of species invasions. Here we compare estimates of real particle dispersion in a coastal marine environment with similar estimates provided by hydrodynamic modelling. We do so by using a system of magnetically attractive particles (MAPs) and a magnetic-collector array that provides measures of Lagrangian dispersion based on the time-integration of MAPs dispersing through the array. MAPs released as a point source in a coastal marine location dispersed through the collector array over a 5-7 d period. A virtual release and observed (real-time) environmental conditions were used in a high-resolution three-dimensional hydrodynamic model to estimate the dispersal of virtual particles (VPs). The number of MAPs captured throughout the collector array and the number of VPs that passed through each corresponding model location were enumerated and compared. Although VP dispersal reflected several aspects of the observed MAP dispersal, the comparisons demonstrated model sensitivity to the small-scale (random-walk) particle diffusivity parameter (Kp). The one-dimensional dispersal kernel for the MAPs had an e-folding scale estimate in the range of 5.19-11.44 km, while those from the model simulations were comparable at 1.89-6.52 km, and also demonstrated sensitivity to Kp. Variations among comparisons are related to the value of Kp used in modelling and are postulated to be related to MAP losses from the water column and (or) shear dispersion acting on the MAPs; a process that is constrained in the model. Our demonstration indicates a promising new way of 1) quantitatively and empirically estimating the dispersal kernel in aquatic systems, and 2) quantitatively assessing and (or) improving regional hydrodynamic

  14. Biodegradation of dispersed oil in Arctic seawater at -1°C.

    PubMed

    McFarlin, Kelly M; Prince, Roger C; Perkins, Robert; Leigh, Mary Beth

    2014-01-01

    As offshore oil and gas exploration expands in the Arctic, it is important to expand the scientific understanding of arctic ecology and environmental impact to mitigate operational risks. Understanding the fate of oil in arctic seawater is a key factor for consideration. Here we report the chemical loss due to the biodegradation of Alaska North Slope (ANS) crude oil that would occur in the water column following the successful dispersion of a surface oil slick. Primary biodegradation and mineralization were measured in mesocosms containing Arctic seawater collected from the Chukchi Sea, Alaska, incubated at -1°C. Indigenous microorganisms degraded both fresh and weathered oil, in both the presence and absence of Corexit 9500, with oil losses ranging from 46-61% and up to 11% mineralization over 60 days. When tested alone, 14% of 50 ppm Corexit 9500 was mineralized within 60 days. Our study reveals that microorganisms indigenous to Arctic seawater are capable of performing extensive biodegradation of chemically and physically dispersed oil at an environmentally relevant temperature (-1°C) without any additional nutrients. PMID:24416211

  15. Biodegradation of Dispersed Oil in Arctic Seawater at -1°C

    PubMed Central

    McFarlin, Kelly M.; Prince, Roger C.; Perkins, Robert; Leigh, Mary Beth

    2014-01-01

    As offshore oil and gas exploration expands in the Arctic, it is important to expand the scientific understanding of arctic ecology and environmental impact to mitigate operational risks. Understanding the fate of oil in arctic seawater is a key factor for consideration. Here we report the chemical loss due to the biodegradation of Alaska North Slope (ANS) crude oil that would occur in the water column following the successful dispersion of a surface oil slick. Primary biodegradation and mineralization were measured in mesocosms containing Arctic seawater collected from the Chukchi Sea, Alaska, incubated at −1°C. Indigenous microorganisms degraded both fresh and weathered oil, in both the presence and absence of Corexit 9500, with oil losses ranging from 46−61% and up to 11% mineralization over 60 days. When tested alone, 14% of 50 ppm Corexit 9500 was mineralized within 60 days. Our study reveals that microorganisms indigenous to Arctic seawater are capable of performing extensive biodegradation of chemically and physically dispersed oil at an environmentally relevant temperature (−1°C) without any additional nutrients. PMID:24416211

  16. Vlasov multi-dimensional model dispersion relation

    SciTech Connect

    Lushnikov, Pavel M.; Rose, Harvey A.; Silantyev, Denis A.; Vladimirova, Natalia

    2014-07-15

    A hybrid model of the Vlasov equation in multiple spatial dimension D > 1 [H. A. Rose and W. Daughton, Phys. Plasmas 18, 122109 (2011)], the Vlasov multi dimensional model (VMD), consists of standard Vlasov dynamics along a preferred direction, the z direction, and N flows. At each z, these flows are in the plane perpendicular to the z axis. They satisfy Eulerian-type hydrodynamics with coupling by self-consistent electric and magnetic fields. Every solution of the VMD is an exact solution of the original Vlasov equation. We show approximate convergence of the VMD Langmuir wave dispersion relation in thermal plasma to that of Vlasov-Landau as N increases. Departure from strict rotational invariance about the z axis for small perpendicular wavenumber Langmuir fluctuations in 3D goes to zero like θ{sup N}, where θ is the polar angle and flows are arranged uniformly over the azimuthal angle.

  17. Analysis of Eight Oil Spill Dispersants Using Rapid, In Vitro Tests for Endocrine and Other Biological Activity

    EPA Science Inventory

    The Deepwater Horizon oil spill has led to the use of >1 M gallons of oil spill dispersants, which are mixtures of surfactants and solvents. Because of this large scale use there is a critical need to understand the potential for toxicity of the currently used dispersant and pote...

  18. OIL SPILL DISPERSANT EFFECTIVENESS PROTOCOL. II: PERFORMANCE OF THE REVISED PROTOCOL

    EPA Science Inventory

    The current U.S. Environmental Protection Agency (EPA) protocol for testing the effectiveness of dispersants for use in treating oil spills on the open water, the swirling flask test (SFT), has been found to give widely varying results in the hands of different testing laborator...

  19. Determining Which Dispersants Will Be Effective In Future Deepwater Oil Spills

    EPA Science Inventory

    Deepwater spills result in oil distributed from deep in the water column to the water surface. The objective of this study was to test eight of the available dispersants (including Corexit 9500A, which was used extensively on the 2010 Deepwater Horizon Spill) on South Louisiana C...

  20. Onset of entrainment and degree of dispersion in dual continuous horizontal oil-water flows

    SciTech Connect

    Al-Wahaibi, Talal; Angeli, Panagiota

    2009-04-15

    The transition from stratified to dual continuous oil-water flow (where each phase retains its continuity but there is dispersion of one phase into the other) as well as the dispersed phase fractions in the layers of the dual continuous pattern, were studied experimentally. Transition to this pattern from stratified flow occurs when drops of one phase appear into the other (onset of entrainment). The studies were carried out in a 38 mm ID horizontal stainless steel test section using two different inlet geometries, a T- and a Y-junction. The patterns were visualized through a transparent acrylic section located at 7 m from the inlet using a high speed video camera. Phase distribution measurements in a pipe cross section were obtained just before the acrylic section with a local impedance probe and the results were used to calculate the volume fraction of each phase entrained into the other. The onset of entrainment was found to occur at lower superficial water velocities as the oil superficial velocities increased. However, the inlet geometry did not affect significantly the transition line. During dual continuous flow, the dispersion of one phase into the opposite was found to extend further away from the interface with increasing water superficial velocity for a certain oil superficial velocity. An increase in the superficial water velocity increased the entrained fraction of water in oil (E{sub w/o}) but there was no trend with the oil velocity. Similarly, an increase in the superficial oil velocity increased the fraction of oil drops in water (E{sub o/w}) but the water velocity had no clear effect. The entrainment fractions were affected by the inlet geometry, with the T-inlet resulting in higher entrainment than the Y-inlet, perhaps because of the increased mixing induced by the T-inlet. The difference between the two inlets increased as the oil and water velocities increased. (author)

  1. Crude oil jets in crossflow: Effects of dispersant concentration on plume behavior

    NASA Astrophysics Data System (ADS)

    Murphy, David W.; Xue, Xinzhi; Sampath, Kaushik; Katz, Joseph

    2016-06-01

    This study investigates the effects of premixing oil with chemical dispersant at varying concentrations on the flow structure and droplet dynamics within a crude oil jet transitioning into a plume in a crossflow. It is motivated by the need to determine the fate of subsurface oil after a well blowout. The laboratory experiments consist of flow visualizations, in situ measurements of the time evolution of droplet-size distributions using holography, and particle image velocimetry to characterize dominant flow features. Increasing the dispersant concentration dramatically decreases the droplet sizes and increases their number, and accordingly, reduces the rise rates of droplets and the upper boundary of the plume. The flow within the plume consists primarily of a pair of counterrotating quasi-streamwise vortices (CVP) that characterize jets in crossflows. It also involves generation of vertical wake vortices that entrain small droplets under the plume. The evolution of plume boundaries is dominated by interactions of droplets with the CVP. The combined effects of vortex-induced velocity and significant quiescent rise velocity of large (˜5 mm) droplets closely agree with the rise rate of the upper boundary of the crude oil plume. Conversely, the much lower rise velocity of the smaller droplets in oil-dispersant mixtures results in plume boundaries rising at rates that are very similar to those of the CVP center. The size of droplets trapped by the CVP is predicted correctly using a trapping function, which is based on a balance of forces on a droplet located within a horizontal eddy.

  2. Effects of ingested crude and dispersed crude oil on thermoregulation in ducks (Anas platyrhynchos)

    SciTech Connect

    Jenssen, B.M.

    1989-02-01

    Thermoregulatory effects of ingested doses of Statfjord A crude oil and of this oil mixed with the dispersant Finasol OSR-5 were studied in adult domestic ducks (Anas platyrhynchos) exposed to ambient temperatures of +16 degrees C and -17 degrees C. The data show that ingestion of both the crude and the oil-dispersant mixture resulted in an increased body temperature during exposure to the low ambient temperature (-17 degrees C). Neither contaminant had any effect on body temperature during exposure to +16 degrees C. Ingestion of the contaminants had no effect on metabolic heat production at either ambient temperature. The breast skin temperature of the ducks in both contaminated groups was significantly decreased when the ducks were exposed to the low ambient temperature. This indicates that the increase in body temperature observed in the contaminated ducks at the low ambient temperature is due to an increase in peripheral vasoconstriction.

  3. Effect of Two Oil Dispersants on Larval Grass Shrimp (Palaemonetes pugio) Development.

    NASA Astrophysics Data System (ADS)

    Betancourt, P.; Key, P. B.; Chung, K. W.; DeLorenzo, M. E.

    2015-12-01

    The study focused on the effects that two oil dispersants, Corexit® EC9500A and Finasol® OSR52, have on the development of larval grass shrimp, (Palaemonetes pugio). The hypothesis was that Finasol would have a greater effect on larval grass shrimp development than Corexit. The experiment was conducted using 300 grass shrimp larvae that were 24 hours old. Each larva was exposed individually. In total, five sub-lethal concentrations were tested for each dispersant (control, 1.25, 2.50, 5.0,10.0 mg/L). The larvae were exposed for five days then transferred to clean seawater until metamorphosis into the juvenile stage. Key data measurements recorded included number of days to become juveniles, number of instars, length, dry weight, and mortality. Data from exposed shrimp was compared to the results of the control for each dispersant concentration. Corexit and Finasol exposure treatments of 5 mg/L and 10 mg/L showed significantly higher values for number of days and number of instars to reach juvenile status than values obtained from unexposed, control shrimp. Overall, mortality was higher in the Finasol treatments but the two dispersants did not respond significantly different from one another. Future studies are needed to determine the long term effects of dispersant exposure on all grass shrimp life stages and how any dispersant exposure impacts grass shrimp populations. Grass shrimp serve as excellent toxicity indicators of estuaries, and further studies will help to develop better oil spill mitigation techniques.

  4. Dispersion model maps spread of Fukushima radiation

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    When water flooded the Japanese Fukushima Daiichi nuclear power plant on 11 March 2011, killing power to the plant and destroying its backup generators, the earthquake-triggered disaster resulted in a major nuclear accident, with the plant pouring radioactive material into the air and the water. Research into the effects of the radiation on humans and the environment has been ongoing, but to ensure the accuracy of these aftermath investigations requires understanding the precise concentrations, distribution patterns, and timing of the radionuclide emissions. To provide such an assessment for the marine environment, Estournel et al. used an ocean and atmosphere dispersion model to simulate the movements of radioactive cesium-137 throughout the Japanese coastal waters for 3.5 months following the earthquake.

  5. CHEMICAL OIL SPILL DISPERSANTS: UPDATE STATE-OF-THE- ART ON MECHANISM OF ACTION AND LABORATORY TESTING FOR PERFORMANCE

    EPA Science Inventory

    Chemical dispersants are formulations designed to facilitate dispersion of an oil slick into small droplets that disperse to non-problematic concentrations in an underlying water column. This project had two primary objectives: (1) update information on mechanisms of action of ...

  6. In Vitro Assessment of Eight Oil Dispersants for Estrogenic, Androgenic, Anti-androgenic and Cytotoxicity in Cell-Based Assays.

    EPA Science Inventory

    Large amounts of dispersants have been used on the oil from the Deepwater Horizon spill and concern has arisen about the toxicity of the dispersants. Some of the dispersants reportedly contain nonylphenol ethoxylates which can degrade to estrogenic compounds, thus the potential...

  7. Dynamics of solid dispersions in oil during the lubrication of point contacts. Part 1: Graphite

    NASA Technical Reports Server (NTRS)

    Cusano, C.; Sliney, H. E.

    1981-01-01

    A Hertzian contact was lubricated with dispersed graphite in mineral oils under boundary lubrication conditions. The contact was optically observed under pure rolling, combined rolling and sliding, and pure sliding conditions. The contact was formed with a steel ball on the flat surface of a glass disk. Photomicrographs are presented which show the distribution of the graphite in and around the contact. Friction and surface damage are also shown for conditions when the base oils are used alone and when graphite is added to the base oils. Under pure rolling and combined rolling and sliding conditions, it is found that, for low speeds, a graphite film can form which will separate the contacting surfaces. Under pure sliding conditions, graphite accumulates at the inlet and sweeps around the contact, but very little of the graphite passes through the contact. The accumulated graphite appears to act as a barrier which reduces the supply of oil available to the contact for boundary lubrication. Friction data show no clear short term beneficial or detrimental effect caused by addition of graphite to the base oil. However, during pure sliding, more abrasion occurs on the polished balls lubricated with the dispersion than on those lubricated with the base oil alone. All observations were for the special case of a highly-polished ball on a glass surface and may not be applicable to other geometries and materials, or to rougher surfaces.

  8. Acute and long-term biological effects of mechanically and chemically dispersed oil on lumpsucker (Cyclopterus lumpus).

    PubMed

    Frantzen, Marianne; Hansen, Bjørn Henrik; Geraudie, Perrine; Palerud, Jocelyn; Falk-Petersen, Inger-Britt; Olsen, Gro H; Camus, Lionel

    2015-04-01

    Concentration dependent differences in acute and long-term effects of a 48 h exposure to mechanically or chemically dispersed crude oil were assessed on juvenile lumpsucker (Cyclopterus lumpus). Acute or post-exposure mortality was only observed at oil concentrations representing higher concentrations than reported after real oil spills. Acute mortality was more apparent in chemically than mechanically dispersed oil treatments whereas comparable EC50s were observed for narcosis. There was a positive correlation between EROD activity and muscle PAH concentration for the lower oil concentrations whereas higher concentrations inhibited the enzyme activity. The incidence of gill tissue lesions was low with no difference between dispersion methods or oil concentrations. A concentration dependent decrease in swimming- and feeding behavior and in SGR was observed at the start of the post-exposure period, but with no differences between corresponding oil treatments. Three weeks post-exposure, fish from all treatments showed as high SGR as the control fish. PMID:25637877

  9. Oil spill removal: Dispersants, absorbents, booms, and skimmers. (Latest citations from the Life Sciences Collection data base). Published Search

    SciTech Connect

    Not Available

    1992-05-01

    The bibliography contains citations concerning the techniques available for the removal of oil following major spills. Chemical dispersants, gelling agents, foam plastics, booms, skimmers, and burning are discussed. Specific oil spills are considered and the environmental impacts of oil spills are noted. (Contains a minimum of 207 citations and includes a subject term index and title list.)

  10. Oil spill removal: Dispersants, absorbents, booms, and skimmers. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations concerning the techniques available for the removal of oil following major spills. Chemical dispersants, gelling agents, foam plastics, booms, skimmers, and burning are discussed. Specific oil spills are considered, and the environmental impacts of oil spills are noted.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  11. Oil spill removal: Dispersants, absorbents, booms, and skimmers. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-10-01

    The bibliography contains citations concerning the techniques available for the removal of oil following major spills. Chemical dispersants, gelling agents, foam plastics, booms, skimmers, and burning are discussed. Specific oil spills are considered, and the environmental impacts of oil spills are noted. (Contains a minimum of 80 citations and includes a subject term index and title list.)

  12. Oil spill removal: Dispersants, absorbents, booms, and skimmers. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-06-01

    The bibliography contains citations concerning the techniques available for the removal of oil following major spills. Chemical dispersants, gelling agents, foam plastics, booms, skimmers, and burning are discussed. Specific oil spills are considered, and the environmental impacts of oil spills are noted. (Contains a minimum of 77 citations and includes a subject term index and title list.)

  13. Oil spill removal: Dispersants, absorbents, booms, and skimmers. (Latest citations from the Life Sciences Collection database). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the techniques available for the removal of oil following major spills. Chemical dispersants, gelling agents, foam plastics, booms, skimmers, and burning are discussed. Specific oil spills are considered, and the environmental impacts of oil spills are noted. (Contains a minimum of 86 citations and includes a subject term index and title list.)

  14. Lubricating oil containing dispersant VII and pour depressant

    SciTech Connect

    Hart, W.P.; Liu, C.S.

    1987-05-26

    This patent describes a functionalized polymer capable of use as an additive in lubricating oils. The process comprises first units, derived from first monomer containing an ethylenically unsaturated carbon-to-carbon double bond; and second units, derived from a different second monomer, a dicarboxylic acid anhydride containing an ethylenically unsaturated carbon-to-carbon double bond; and the polymer bearing, bonded to the dicarboxylic-acid-derived moiety, functionalizing groups derived from: a primary or secondary functionalizing amine R/sup 7//sub 2/(NR/sup 9/)/sub ..cap alpha../NR/sup 8//sub 2/ where R/sup 7/ is alkyl, alkaryl, aralkyl, cycloalkyl, or aryl hydrocarbon, R/sup 8/ is hydrogen or selected from the same group as in R/sup 7/, R/sup 9/ is alkylene, aralkylene, cycloalkylene, alkarylene, or arylene, and a is 0.20. The amine is bonded to the polymer through a nitrogen atom of the amine group; and, a functionalizing Mannich base is formed by reacting a phenol containing an active hydrogen atom, an aldehyde and a primary or secondary polyamine. The Mannich base is bonded to the polymer through a nitrogen atom of the amine group.

  15. Ecological considerations for the use of dispersants in oil spill response

    USGS Publications Warehouse

    Lindstedt-Siva, J.; Albers, P.H.; Fucik, K.W.; Maynard, N.G.

    1984-01-01

    A multidisciplinary task force with membership from government agencies, academia, and industry is developing ecologically based guidelines for dispersant use in marine and estuarine environments. The guidelines are organized by habitat type (e.g., coral reefs, rocky shores, bird habitats) and consider dispersant use to protect the habitats from impact, to mitigate impacts, and to clean the habitats after a spill. Each guideline contains a description of the habitat type covered, recommendations for dispersant use, and a background section reviewing the relevant literature. The goal is to minimize the ecological impacts of oil spills. Aesthetic, socioeconomic, and political factors are not considered, although it is recognized that these are important concerns during spill response. Use of dispersants is considered along with other appropriate countermeasures and compared with the “no cleanup” alternative.

  16. Tracking the Deepwater Horizon Oil Spill: A Modeling Perspective

    NASA Astrophysics Data System (ADS)

    Liu, Yonggang; Weisberg, Robert H.; Hu, Chuanmin; Zheng, Lianyuan

    2011-02-01

    The Deepwater Horizon oil spill was caused by a drilling rig explosion on 20 April 2010 that killed 11 people. It was the largest oil spill in U.S. history and presented an unprecedented threat to Gulf of Mexico marine resources. Although oil gushing to the surface diminished after the well was capped, on 15 July 2010, much remains to be known about the oil and the dispersants beneath the surface, including their trajectories and effects on marine life. A system for tracking the oil, both at the surface and at depth, was needed for mitigation efforts and ship survey guidance. Such a system was implemented immediately after the spill by marshaling numerical model and satellite remote sensing resources available from existing coastal ocean observing activities [e.g., Weisberg et al., 2009]. Analyzing this system's various strengths and weaknesses can help further improve similar systems designed for other emergency responses.

  17. DETERMINING DISPERSANT EFFECTIVENESS DATA FOR A SUITE OF ENVIRONMENTAL CONDITIONS

    EPA Science Inventory

    Chemical dispersants are used in oil spill response operations to enhance the dispersion of oil slicks at sea as small oil droplets in the water column. To assess the impacts of dispersant usage on oil spills, US EPA is developing a simulation model called the EPA Research Objec...

  18. Using empirical data to model transgene dispersal.

    PubMed Central

    Meagher, T R; Belanger, F C; Day, P R

    2003-01-01

    One element of the current public debate about genetically modified crops is that gene flow from transgenic cultivars into surrounding weed populations will lead to more problematic weeds, particularly for traits such as herbicide resistance. Evolutionary biologists can inform this debate by providing accurate estimates of gene flow potential and subsequent ecological performance of resulting hybrids. We develop a model for gene flow incorporating exponential distance and directional effects to be applied to windpollinated species. This model is applied to previously published data on gene flow in experimental plots of Agrostis stolonifera L. (creeping bentgrass), which assessed gene flow from transgenic plants resistant to the herbicide glufosinate to surrounding non-transgenic plants. Our results show that although pollen dispersal can be limited in some sites, it may be extensive in others, depending on local conditions such as exposure to wind. Thus, hybridization under field conditions is likely to occur. Given the nature of the herbicide resistance trait, we regard this trait as unlikely to persist in the absence of herbicide, and suggest that the ecological consequences of such gene flow are likely to be minimal. PMID:12831482

  19. Physical modeling of gas dispersion over urban area

    NASA Astrophysics Data System (ADS)

    Michálek, Petr; Zacho, David

    2016-06-01

    Experimental study of gas dispersion over urban area model was conducted in boundary layer wind tunnel in VZLU Prague. A scale model of urban area near the Centre of Liberec was made and dispersion of gas emissions from nearby heating plant was measured. The measurements included velocity field and concentration field by means of hot wire anemometer and flame ionization detector. The purpose of this work was to validate and verify a new computational dispersion model, which was developed in VZLU.

  20. Self-dispersed crumpled graphene balls in oil for friction and wear reduction

    PubMed Central

    Dou, Xuan; Koltonow, Andrew R.; He, Xingliang; Jang, Hee Dong; Wang, Qian; Chung, Yip-Wah; Huang, Jiaxing

    2016-01-01

    Ultrafine particles are often used as lubricant additives because they are capable of entering tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. It is highly desirable for these particles to remain well dispersed in oil without relying on molecular ligands. Borrowing from the analogy that pieces of paper that are crumpled do not readily stick to each other (unlike flat sheets), we expect that ultrafine particles resembling miniaturized crumpled paper balls should self-disperse in oil and could act like nanoscale ball bearings to reduce friction and wear. Here we report the use of crumpled graphene balls as a high-performance additive that can significantly improve the lubrication properties of polyalphaolefin base oil. The tribological performance of crumpled graphene balls is only weakly dependent on their concentration in oil and readily exceeds that of other carbon additives such as graphite, reduced graphene oxide, and carbon black. Notably, polyalphaolefin base oil with only 0.01–0.1 wt % of crumpled graphene balls outperforms a fully formulated commercial lubricant in terms of friction and wear reduction. PMID:26811466

  1. Self-dispersed crumpled graphene balls in oil for friction and wear reduction.

    PubMed

    Dou, Xuan; Koltonow, Andrew R; He, Xingliang; Jang, Hee Dong; Wang, Qian; Chung, Yip-Wah; Huang, Jiaxing

    2016-02-01

    Ultrafine particles are often used as lubricant additives because they are capable of entering tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. It is highly desirable for these particles to remain well dispersed in oil without relying on molecular ligands. Borrowing from the analogy that pieces of paper that are crumpled do not readily stick to each other (unlike flat sheets), we expect that ultrafine particles resembling miniaturized crumpled paper balls should self-disperse in oil and could act like nanoscale ball bearings to reduce friction and wear. Here we report the use of crumpled graphene balls as a high-performance additive that can significantly improve the lubrication properties of polyalphaolefin base oil. The tribological performance of crumpled graphene balls is only weakly dependent on their concentration in oil and readily exceeds that of other carbon additives such as graphite, reduced graphene oxide, and carbon black. Notably, polyalphaolefin base oil with only 0.01-0.1 wt % of crumpled graphene balls outperforms a fully formulated commercial lubricant in terms of friction and wear reduction. PMID:26811466

  2. Dispersed oil toxicity tests with biological species indigenous to the Gulf of Mexico. Final report

    SciTech Connect

    Fucik, K.W.; Carr, K.A.; Balcom, B.J.

    1994-08-01

    Static and flowthrough aquatic acute toxicity testing protocols were utilized on eggs and larvae of seven commercially important invertebrates and fishes from the Gulf of Mexico. Test organisms were exposed to Central and Western Gulf oils, dispersed oil, and Corexit 9527. Species included brown shrimp (Penaeus aztecus), white shrimp (Penaeus setiferus), blue crab (Callinectes sapidus), eastern oyster (Crassostrea virginica), red drum (Sciaenops ocellatus), inland silverside (Menidia berylina), and spot (Leiosomus xanthurus). Atlantic menhaden (Brevoortia tyrannus) was also tested because gulf menhaden were not available. Mysids (Mysidopsis bahia) were evaluated as part of a chronic toxicity assessment.

  3. Fabrication of silver nanoparticles dispersed in palm oil using laser ablation.

    PubMed

    Zamiri, Reza; Zakaria, Azmi; Ahangar, Hossein Abbastabar; Sadrolhosseini, Amir Reza; Mahdi, Mohd Adzir

    2010-01-01

    In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time. PMID:21151470

  4. Biodegradability of Corexit 9500 and dispersed South Louisiana crude oil at 5 and 25 °C.

    PubMed

    Campo, Pablo; Venosa, Albert D; Suidan, Makram T

    2013-02-19

    The reported persistence of the dioctyl sodium sulfosuccinate (DOSS) surfactant in Corexit 9500 in the oil plumes formed during the Deepwater Horizon oil spill has contributed to concerns regarding the biodegradability and bioavailability of dispersed oil and dispersants used as an oil spill countermeasure in the Gulf of Mexico. We studied the biodegradation of DOSS and dispersed South Louisiana crude oil (SLC) in laboratory microcosms. Two oil-degrading cultures from the Gulf of Mexico were isolated, one from the surface (meso) and one from close to the area of the Macondo well (cryo). Each was enriched on SLC, the former at 25 °C, the latter at 5 °C. Results indicated that the meso culture rapidly and completely degraded DOSS, alkanes, and aromatics. The cryo culture metabolized the same compounds but with a lag of 28 d and a remaining residual of iso-alkanes, n-C(30-35), and the 4-ring PAHs. PMID:23363064

  5. Surface active compositions and method of use in dispersing or collecting oil slick

    SciTech Connect

    Lepain, A.O.

    1980-09-23

    Disclosed are surface-active compositions for dispersing or collecting oil slicks on water or for protecting or cleaning beaches, which compositions comprise (A) a mixture of surface-active compounds comprising at least one solid compound and at least one liquid compound, and (B) a mixture of solvents comprising a glycol ether and at least one n-paraffin having from about 10 to 16 carbon atoms.

  6. Modelling Aerosol Dispersion in Urban Street Canyons

    NASA Astrophysics Data System (ADS)

    Tay, B. K.; Jones, D. P.; Gallagher, M. W.; McFiggans, G. B.; Watkins, A. P.

    2009-04-01

    Flow patterns within an urban street canyon are influenced by various micrometeorological factors. It also represents an environment where pollutants such as aerosols accumulate to high levels due to high volumes of traffic. As adverse health effects are being attributed to exposure to aerosols, an investigation of the dispersion of aerosols within such environments is of growing importance. In particular, one is concerned with the vertical structure of the aerosol concentration, the ventilation characteristics of the street canyon and the influence of aerosol microphysical processes. Due to the inherent heterogeneity of the aerosol concentrations within the street canyon and the lack of spatial resolution of measurement campaigns, these issues are an on-going debate. Therefore, a modelling tool is required to represent aerosol dispersion patterns to provide insights to results of past measurement campaigns. Computational Fluid Dynamics (CFD) models are able to predict detailed airflow patterns within urban geometries. This capability may be further extended to include aerosol dispersion, by an Euler-Euler multiphase approach. To facilitate the investigation, a two-dimensional, multiphase CFD tool coupled with the k-epsilon turbulence model and with the capability of modelling mixed convection flow regimes arising from both wind driven flows and buoyancy effects from heated walls was developed. Assuming wind blowing perpendicularly to the canyon axis and treating aerosols as a passive scalar, an attempt will be made to assess the sensitivities of aerosol vertical structure and ventilation characteristics to the various flow conditions. Numerical studies were performed using an idealized 10m by 10m canyon to represent a regular canyon and 10m by 5m to represent a deep one. An aerosol emission source was assigned on the centerline of the canyon to represent exhaust emissions. The vertical structure of the aerosols would inform future directives regarding the

  7. Wind tunnel modeling of heavy gas dispersion

    NASA Astrophysics Data System (ADS)

    König-Langlo, G.; Schatzmann, M.

    Assessment of risk attending the manufacturing, storing and transportation of flammable and toxic gases involves the quantification of the ensuing dispersion in case of an accidental release. Worst case considerations have to be applied in order to obtain conservative estimates The paper describes a method for the determination of lower flammability distances for gases heavier than air under unfavorable atmospheric conditions. The method is based on the results of a wind tunnel study investigating the dispersion of instantaneous as well as continuous releases into a boundary-layer shear flow disturbed and undisturbed by surface obstacles. Thermodynamic effects on the dispersing cloud have been taken into account through modification of source parameters. The results have been compared with those from corresponding field trials. The agreement is generally fair. The method has now been converted into a detailed guideline for dispersion calculations within risk assessment studies for flammable and toxic heavy gases (VDI 3783, Part 2, Beuth Verlag, Berlin, 1990).

  8. The oil spill model OILTRANS and its application to the Celtic Sea.

    PubMed

    Berry, Alan; Dabrowski, Tomasz; Lyons, Kieran

    2012-11-01

    This paper describes details of an oil spill model, OILTRANS, developed by the authors. The model is an off-line particle-transport model coupled to the most up to date operational met-ocean model forecasts. Formulations for the dominant oil fate processes of spreading, advection, diffusion, evaporation, emulsification and dispersion have been encoded, providing the model with the ability to accurately predict the horizontal movement of surface oil slick, the vertical entrainment of oil into the water column and the mass balance of spilled oil. The application of the OILTRANS model to an accidental release during a ship-to-ship fuel transfer in the Celtic Sea in February 2009 is presented to validate the system. Comparisons with aerial observations of the oil slick at the time of the incident, and subsequent model simulations, indicate that the OILTRANS model is capable of accurately predicting the transport and fate of the oil slick. PMID:22901703

  9. Deep-sea bacteria enriched by oil and dispersant from the Deepwater Horizon spill.

    PubMed

    Baelum, Jacob; Borglin, Sharon; Chakraborty, Romy; Fortney, Julian L; Lamendella, Regina; Mason, Olivia U; Auer, Manfred; Zemla, Marcin; Bill, Markus; Conrad, Mark E; Malfatti, Stephanie A; Tringe, Susannah G; Holman, Hoi-Ying; Hazen, Terry C; Jansson, Janet K

    2012-09-01

    The Deepwater Horizon oil spill resulted in a massive influx of hydrocarbons into the Gulf of Mexico (the Gulf). To better understand the fate of the oil, we enriched and isolated indigenous hydrocarbon-degrading bacteria from deep, uncontaminated waters from the Gulf with oil (Macondo MC252) and dispersant used during the spill (COREXIT 9500). During 20 days of incubation at 5°C, CO(2) evolution, hydrocarbon concentrations and the microbial community composition were determined. Approximately 60% to 25% of the dissolved oil with or without COREXIT, respectively, was degraded, in addition to some hydrocarbons in the COREXIT. FeCl(2) addition initially increased respiration rates, but not the total amount of hydrocarbons degraded. 16S rRNA gene sequencing revealed a succession in the microbial community over time, with an increase in abundance of Colwellia and Oceanospirillales during the incubations. Flocs formed during incubations with oil and/or COREXIT in the absence of FeCl(2) . Synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy revealed that the flocs were comprised of oil, carbohydrates and biomass. Colwellia were the dominant bacteria in the flocs. Colwellia sp. strain RC25 was isolated from one of the enrichments and confirmed to rapidly degrade high amounts (approximately 75%) of the MC252 oil at 5°C. Together these data highlight several features that provide Colwellia with the capacity to degrade oil in cold, deep marine habitats, including aggregation together with oil droplets into flocs and hydrocarbon degradation ability. PMID:22616650

  10. Effects of oil spill dispersants and drilling fluids on substrate specificity of marine bacteria

    SciTech Connect

    Okpokwasili, G.C.; Nnubia, C.

    1995-12-31

    The effects of oil spill dispersants and drilling fluids on the sizes of populations of specific heterotroph subgroups of marine bacteria were monitored in this study. The bacteria were isolated from drill cuttings recovered from Agbara--an offshore oilfield located some 100 nautical miles off the Atlantic coast of Nigeria. Numbers of cellulolytic, proteolytic, starch-hydrolyzing and lipolytic bacteria in the drill cuttings were monitored for 28 days in the presence of oil spill dispersants and drilling fluids. The percentages of these bacterial subgroups within the total heterotrophic population enumerated on tryptic soy agar (10% with 3% NaCl) fluctuated between 3.0 and 17.0%, 0.0 and 27.0%, 4.0 and 25.0% and 3.0 and 18.0% for cellulolytic, proteolytic, starch-hydrolyzing and lipolytic bacteria respectively. These results indicate that oil spill dispersants and drilling fluids affect the ability of marine bacteria to metabolize these substrates in the environment.

  11. Estimating sub-surface dispersed oil concentration using acoustic backscatter response.

    PubMed

    Fuller, Christopher B; Bonner, James S; Islam, Mohammad S; Page, Cheryl; Ojo, Temitope; Kirkey, William

    2013-05-15

    The recent Deepwater Horizon disaster resulted in a dispersed oil plume at an approximate depth of 1000 m. Several methods were used to characterize this plume with respect to concentration and spatial extent including surface supported sampling and autonomous underwater vehicles with in situ instrument payloads. Additionally, echo sounders were used to track the plume location, demonstrating the potential for remote detection using acoustic backscatter (ABS). This study evaluated use of an Acoustic Doppler Current Profiler (ADCP) to quantitatively detect oil-droplet suspensions from the ABS response in a controlled laboratory setting. Results from this study showed log-linear ABS responses to oil-droplet volume concentration. However, the inability to reproduce ABS response factors suggests the difficultly in developing meaningful calibration factors for quantitative field analysis. Evaluation of theoretical ABS intensity derived from the particle size distribution provided insight regarding method sensitivity in the presence of interfering ambient particles. PMID:23490350

  12. Dispersion modelling approaches for near road applications involving noise barriers

    EPA Science Inventory

    The talk will present comparisons with two datasets of the barrier algorithms implemented in two different dispersion models: US EPA’s R-LINE (a research dispersion modelling tool under development by the US EPA’s Office of Research and Development) and CERC’s A...

  13. Developmental abnormalities and differential expression of genes induced in oil and dispersant exposed Menidia beryllina embryos.

    PubMed

    Adeyemo, Olanike K; Kroll, Kevin J; Denslow, Nancy D

    2015-11-01

    Exposure of fish embryos to relatively low concentrations of oil has been implicated in sub-lethal toxicity. The objective of this study was to determine the effects of the exposure of Menidia beryllina embryos at 30-48h post-fertilization to the water accommodated fractions of oil (WAF, 200ppm, v/v), dispersants (20ppm, v/v, Corexit 9500 or 9527), and mixtures of oil and each of the dispersants to produce chemically enhanced water accommodated fractions (CEWAFs) over a 72-hour period. The polyaromatic hydrocarbon (PAH) and benzene, toluene, ethylene and xylene (BTEX) constituents of the 5X concentrated exposure solutions (control, WAF, dispersants and CEWAFs) were determined and those of the 1× exposures were derived using a dilution factor. PAH, BTEX and low molecular weight PAH constituents greater than 1ppb were observed in WAF and the dispersants, but at much higher levels in CEWAFs. The WAF and CEWAFs post-weathering were diluted at 1:5 (200ml WAF/CEWAF: 800ml 25ppt saltwater) for embryo exposures. Mortality, heartbeat, embryo normalcy, abnormality types and severities were recorded. The qPCR assay was used to quantify abundances of transcripts of target genes for sexual differentiation and sex determination (StAR, dmrt-1, amh, cyp19b, vtg and chg-L,), growth regulation (ghr) and stress response (cyp1a and Hsp90); and gapdh served as the housekeeping gene. Temperature was 21±1.5°C throughout the experimental period, while mortality was low and not significantly different (p=0.68) among treatments. Heartbeat was significantly different (0.0034) with the lowest heartbeats recorded in Corexit 9500 (67.5beats/min) and 9527 (67.1beats/min) exposed embryos compared with controls (82.7beats/min). Significantly more treated embryos were in a state of deterioration, with significantly more embryos presenting arrested tissue differentiation compared with controls (p=0.021). Exposure to WAF, dispersants and CEWAF induced aberrant expression of all the genes, with

  14. Air-dispersion modeling and the real world

    SciTech Connect

    Beychok, M.T.

    1996-06-01

    Use of computerized programs to model stack-gas dispersion mathematically has grown immensely in the last 15 years. In most dispersion models, determining ground-level pollutant concentrations beneath an elevated, buoyant plume of dispersing stack gas involves two major steps. First, the height to which the plume rises at a given downward distance from the plume source is calculated. The calculated plume rise is added to the height of the source stack, or emission point, to determine the effective stack height, also called the plume centerline height. Second, ground-level concentrations beneath the plume are predicted using the Gaussian dispersion equation.

  15. Oil separation from wet milled corn germ dispersions as part of aqueous oil extraction and aqueous enzymatic oil extraction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oil was obtained from corn germ by aqueous extraction (AE). 100 g batches of germ were mixed with a buffer solution to a mass concentration of 5 to 20% germ, preheated under 2 atm. pressure (120oC), milled in a blender and then churned in an incubator/shaker to coalesce and float oil droplets. The ...

  16. Dispersion analysis with inverse dielectric function modelling.

    PubMed

    Mayerhöfer, Thomas G; Ivanovski, Vladimir; Popp, Jürgen

    2016-11-01

    We investigate how dispersion analysis can profit from the use of a Lorentz-type description of the inverse dielectric function. In particular at higher angles of incidence, reflectance spectra using p-polarized light are dominated by bands from modes that have their transition moments perpendicular to the surface. Accordingly, the spectra increasingly resemble inverse dielectric functions. A corresponding description can therefore eliminate the complex dependencies of the dispersion parameters, allow their determination and facilitate a more accurate description of the optical properties of single crystals. PMID:27294550

  17. Trace Analysis of Surfactants in Corexit Oil Dispersant Formulations and Seawater

    PubMed Central

    Place, Benjamin J.; Perkins, Matt J.; Sinclair, Ewan; Barsamian, Adam L.; Blakemore, Paul R.; Field, Jennifer A.

    2014-01-01

    After the April 2010 explosion on the Deepwater Horizon oil rig, and subsequent release of millions of barrels of oil, two Corexit oil dispersant formulations were used in unprecedented quantities both on the surface and sub-surface of the Gulf of Mexico. Although the dispersant formulations contain four classes of surfactants, current studies to date focus on the anionic surfactant, bis-(2-ethylhexyl) sulfosuccinate (DOSS). Factors affecting the integrity of environmental and laboratory samples for Corexit analysis have not been systematically investigated. For this reason, a quantitative analytical method was developed for the detection of all four classes of surfactants, as well as the hydrolysis products of DOSS, the enantiomeric mixture of α- and β-ethylhexyl sulfosuccinate (α-/β-EHSS). The analytical method was then used to evaluate which practices for sample collection, storage, and analysis resulted in high quality data. Large volume, direct injection of seawater followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) minimized analytical artifacts, analysis time, and both chemical and solid waste. Concentrations of DOSS in the seawater samples ranged from 71 – 13,000 ng/L, while the nonionic surfactants including Span 80, Tween 80, Tween 85 were detected infrequently (26% of samples) at concentrations from 840 – 9100 ng/L. The enantiomers α-/β-EHSS were detected in seawater, at concentrations from 200 – 1,900 ng/L, and in both Corexit dispersant formulations, indicating α-/β-EHSS were applied to the oil spill and may be not unambiguous indicator of DOSS degradation. Best practices are provided to ensure sample integrity and data quality for environmental monitoring studies and laboratory that require the detection and quantification of Corexit-based surfactants in seawater.

  18. Stochastic simulation model of oil spill fate and transfer

    SciTech Connect

    Al-Rabeh, A.H.; Cekirge, H.M.; Gunay, N. )

    1989-06-01

    Over the past few years, considerable research has been directed toward the development of mathematical models to describe the behavior of oil spills. A successful model would be of great value in selecting locations for the deployment of containment and collection systems to mitigate the effects of the pollutant on the environment. In this study, a comprehensive stochastic model is formulated to simulate the fate and transport of oil spills. The model consists of a set of algorithms describing the processes of advection, turbulent diffusion, surface spreading, vertical mechanical dispersion, emulsification, and evaporation. Each algorithm is developed separately and is linked to related processes and to environmental and other parameters. The model requires as input the velocity field of the transporting medium. This can be obtained from a three-dimensional hydrodynamic model for tidal and wind-driven currents for the region of interest. The oil spill fate and transport model is used to simulate a surface oil spill in the Abu Ali region on the western side of the Arabian Gulf. The simulation results indicate that the model can predict the fate and transport of oil slicks with reasonable accuracy. 45 refs., 10 figs.

  19. Effects of dispersed oil on reproduction in the cold water copepod Calanus finmarchicus (Gunnerus)

    PubMed Central

    Olsen, Anders Johny; Nordtug, Trond; Altin, Dag; Lervik, Morten; Hansen, Bjørn Henrik

    2013-01-01

    Following a 120-h exposure period to 3 concentrations of oil dispersions (0.022 mg L−1, 1.8 mg L−1, and 16.5 mg L−1, plus controls) generated from a North Sea crude oil and a subsequent 21-d recovery, mortality, and several reproduction endpoints (egg production rates, egg hatching success, and fraction of females participating in reproduction) in Calanus finmarchicus were studied. Concentration-dependent mortality was found during exposure, averaging to 6%, 3%, 15%, and 42% for the controls and 3 exposure levels, respectively. At the start of the recovery period, mean egg production rates of surviving females from the highest concentrations were very low, but reproduction subsequently improved. In a 4-d single female reproduction test starting 13 d postexposure, no significant differences in egg production rates or hatching success were found between reproducing control and exposed copepods. However, a significantly lower portion of the surviving females from the highest exposure participated in egg production. The results indicate that although short-term exposure to oil-polluted water after an oil spill can induce severe mortality and temporarily suspend reproduction, copepods may recover and produce viable offspring soon after exposure. The results might imply that for C. finmarchicus populations, the impact from short-term exposure to an oil spill might be predicted from acute mortality and that delayed effects make only a limited contribution to population decrease. PMID:23661343

  20. Oil spill hazard from dispersal of oil along shipping lanes in the Southern Adriatic and Northern Ionian Seas.

    PubMed

    Liubartseva, S; De Dominicis, M; Oddo, P; Coppini, G; Pinardi, N; Greggio, N

    2015-01-15

    An assessment of hazard stemming from operational oil ship discharges in the Southern Adriatic and Northern Ionian (SANI) Seas is presented. The methodology integrates ship traffic data, the fate and transport oil spill model MEDSLIK-II, coupled with the Mediterranean Forecasting System (MFS) ocean currents, sea surface temperature analyses and ECMWF surface winds. Monthly and climatological hazard maps were calculated for February 2009 through April 2013. Monthly hazard distributions of oil show that the zones of highest sea surface hazard are located in the southwestern Adriatic Sea and eastern Ionian Sea. Distinctive "hot spots" appear in front of the Taranto Port and the sea area between Corfu Island and the Greek coastlines. Beached oil hazard maps indicate the highest values in the Taranto Port area, on the eastern Greek coastline, as well as in the Bari Port area and near Brindisi Port area. PMID:25455790

  1. A dynamic model for the Lagrangian stochastic dispersion coefficient

    SciTech Connect

    Pesmazoglou, I.; Navarro-Martinez, S.; Kempf, A. M.

    2013-12-15

    A stochastic sub-grid model is often used to accurately represent particle dispersion in turbulent flows using large eddy simulations. Models of this type have a free parameter, the dispersion coefficient, which is not universal and is strongly grid-dependent. In the present paper, a dynamic model for the evaluation of the coefficient is proposed and validated in decaying homogeneous isotropic turbulence. The grid dependence of the static coefficient is investigated in a turbulent mixing layer and compared to the dynamic model. The dynamic model accurately predicts dispersion statistics and resolves the grid-dependence. Dispersion statistics of the dynamically calculated constant are more accurate than any static coefficient choice for a number of grid spacings. Furthermore, the dynamic model produces less numerical artefacts than a static model and exhibits smaller sensitivity in the results predicted for different particle relaxation times.

  2. Numerical modelling of mesoscale atmospheric dispersion. (Volumes I and II)

    SciTech Connect

    Moran, M.D.

    1992-01-01

    Mesoscale atmospheric dispersion is more complicated than smaller-scale dispersion because the mean wind field can no longer be considered steady or horizontally homogeneous over mesoscale time and space scales. Wind shear also plays an important role on the mesoscale, and horizontal dispersion can be enhanced and even dominated by vertical wind shear through either the simultaneous or delayed interaction of horizontal differential advection and vertical mixing. The CSU mesoscale atmospheric dispersion modelling system has been used in this study to simulate the transport and diffusion of a perfluorocarbon gas for episodic releases made during two mesoscale dispersion field experiments. The physiography of the two experimental domains was quite different, permitting isolation and examination of the roles of terrain forcing and differential advection in mesoscale atmospheric dispersion. Suites of numerical experiments of increasing complexity were carried out for both case studies. The experiments differed in the realism of their representation of both the synoptic-scale flow and the underlying terrain. The contributions of differential advection and mesoscale deformation to mesoscale dispersion dominated those of small-scale turbulent diffusion for both cases, and Pasquill's (1962) delayed-shear-enhancement mechanism for lateral dispersion was found to be particularly important. This study was also the first quantitative evaluation of the CSU mesoscale dispersion modelling system with episodic mesoscale dispersion field data. The modelling system showed considerable skill in predicting quantitative tracer-cloud characteristics such as peak concentration, maximum cloud width, arrival time, transit time, and crosswind integrated exposure. Model predictions also compared favorably with predictions made by a number of other mesoscale dispersion models for the same two case studies.

  3. Magnetite nanoparticles as-prepared and dispersed in Copaiba oil: study using magnetic measurements and Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Oshtrakh, Michael I.; Ushakov, Mikhail V.; Semenova, Anna S.; Kellerman, Dina G.; Šepelák, Vladimir; Rodriguez, Alfonso F. R.; Semionkin, Vladimir A.; Morais, Paulo C.

    2013-04-01

    Study of magnetite nanoparticles, as-prepared and dispersed in Copaiba oil as magnetic fluid, by means of magnetic measurement and Mössbauer spectroscopy at various temperatures demonstrated differences in the saturation magnetization and Mössbauer hyperfine parameters which were related to the interactions of Copaiba oil polar molecules with iron cations on magnetite nanoparticle's surface.

  4. Comparative Laboratory-Scale Testing of Dispersant Effectiveness of 23 Crude Oils Using Four Different Testing Protocols

    EPA Science Inventory

    A controlled laboratory study was conducted to measure the dispersion effectiveness of Corexit 9500 on 20 different crude oils. This study was a part of a larger project initiated by the Bureau of Safety and Environmental Enforcement (BSEE) testing 20 oils to compare the predict...

  5. Comparative Toxicity of Louisiana Sweet Crude Oil (LSC) and Chemically Dispersed LSC to Two Gulf of Mexico Aquatic Test Species.

    EPA Science Inventory

    Environmental Protection Agency released peer reviewed results from the second phase of its independent toxicity testing on mixtures of eight oil dispersants with Louisiana Sweet Crude Oil. EPA conducted the tests as part of an effort to ensure that EPA decisions remain grounded ...

  6. Decrease in osmotically driven water flux and transport through mangrove roots after oil spills in the presence and absence of dispersants.

    PubMed

    Tansel, Berrin; Arreaza, Ariadna; Tansel, Derya Z; Lee, Mengshan

    2015-09-15

    The objective of this study was to evaluate the effect of crude oil on water transport through mangroves roots in the presence and absence of dispersants. Water transport through the roots were evaluated experimentally using red mangrove root segments exposed to salt water contaminated with Louisiana crude oil for seven days in the presence and absence of Corexit 9500A (dispersant). Experimental observations were interpreted in view of the structural integrity and fouling phenomena observed on the epidermis and endodermis layers of the roots. The effects of oil on the radial water flux through the epidermis and endodermis were analyzed using a dual layer filtration model. Progression of fouling due to accumulation and penetration of the contaminants through the root layers were interpreted in relation to observed mangrove health (long and short term effects) reported in the literature. PMID:26183309

  7. Atmospheric Dispersion Model Validation in Low Wind Conditions

    SciTech Connect

    Sawyer, Patrick

    2007-11-01

    Atmospheric plume dispersion models are used for a variety of purposes including emergency planning and response to hazardous material releases, determining force protection actions in the event of a Weapons of Mass Destruction (WMD) attack and for locating sources of pollution. This study provides a review of previous studies that examine the accuracy of atmospheric plume dispersion models for chemical releases. It considers the principles used to derive air dispersion plume models and looks at three specific models currently in use: Aerial Location of Hazardous Atmospheres (ALOHA), Emergency Prediction Information Code (EPIcode) and Second Order Closure Integrated Puff (SCIPUFF). Results from this study indicate over-prediction bias by the EPIcode and SCIPUFF models and under-prediction bias by the ALOHA model. The experiment parameters were for near field dispersion (less than 100 meters) in low wind speed conditions (less than 2 meters per second).

  8. Development and Practical Application of Petroleum and Dispersant Interspecies Correlation Models for Aquatic Species

    EPA Science Inventory

    Assessing the acute toxicity of physically and chemically dispersed oil following an oil spill has generally relied on existing toxicological data for a relatively limited number of aquatic species. Recognition of differences in species sensitivities to contaminants has facilitat...

  9. Modelling non-symmetric collagen fibre dispersion in arterial walls

    PubMed Central

    Holzapfel, Gerhard A.; Niestrawska, Justyna A.; Ogden, Ray W.; Reinisch, Andreas J.; Schriefl, Andreas J.

    2015-01-01

    New experimental results on collagen fibre dispersion in human arterial layers have shown that the dispersion in the tangential plane is more significant than that out of plane. A rotationally symmetric dispersion model is not able to capture this distinction. For this reason, we introduce a new non-symmetric dispersion model, based on the bivariate von Mises distribution, which is used to construct a new structure tensor. The latter is incorporated in a strain-energy function that accommodates both the mechanical and structural features of the material, extending our rotationally symmetric dispersion model (Gasser et al. 2006 J. R. Soc. Interface 3, 15–35. (doi:10.1098/rsif.2005.0073)). We provide specific ranges for the dispersion parameters and show how previous models can be deduced as special cases. We also provide explicit expressions for the stress and elasticity tensors in the Lagrangian description that are needed for a finite-element implementation. Material and structural parameters were obtained by fitting predictions of the model to experimental data obtained from human abdominal aortic adventitia. In a finite-element example, we analyse the influence of the fibre dispersion on the homogeneous biaxial mechanical response of aortic strips, and in a final example the non-homogeneous stress distribution is obtained for circumferential and axial strips under fixed extension. It has recently become apparent that this more general model is needed for describing the mechanical behaviour of a variety of fibrous tissues. PMID:25878125

  10. Modelling long-distance seed dispersal in heterogeneous landscapes.

    SciTech Connect

    Levey, Douglas, J.; Tewlsbury, Joshua, J.; Bolker, Benjamin, M.

    2008-01-01

    1. Long-distance seed dispersal is difficult to measure, yet key to understanding plant population dynamics and community composition. 2. We used a spatially explicit model to predict the distribution of seeds dispersed long distances by birds into habitat patches of different shapes. All patches were the same type of habitat and size, but varied in shape. They occurred in eight experimental landscapes, each with five patches of four different shapes, 150 m apart in a matrix of mature forest. The model was parameterized with smallscale movement data collected from field observations of birds. In a previous study we validated the model by testing its predictions against observed patterns of seed dispersal in real landscapes with the same types and spatial configuration of patches as in the model. 3. Here we apply the model more broadly, examining how patch shape influences the probability of seed deposition by birds into patches, how dispersal kernels (distributions of dispersal distances) vary with patch shape and starting location, and how movement of seeds between patches is affected by patch shape. 4. The model predicts that patches with corridors or other narrow extensions receive higher numbers of seeds than patches without corridors or extensions. This pattern is explained by edgefollowing behaviour of birds. Dispersal distances are generally shorter in heterogeneous landscapes (containing patchy habitat) than in homogeneous landscapes, suggesting that patches divert the movement of seed dispersers, ‘holding’ them long enough to increase the probability of seed defecation in the patches. Dispersal kernels for seeds in homogeneous landscapes were smooth, whereas those in heterogenous landscapes were irregular. In both cases, long-distance (> 150 m) dispersal was surprisingly common, usually comprising approximately 50% of all dispersal events. 5. Synthesis . Landscape heterogeneity has a large influence on patterns of long-distance seed dispersal. Our