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Sample records for contaminant-sediment interactions volume

  1. Solid-waste leach characteristics and contaminant-sediment interactions. Volume 1, Batch leach and adsorption tests and sediment characterization

    SciTech Connect

    Serne, R.J.; LeGore, V.L.; Cantrell, K.J.; Lindenmeier, C.W.; Campbell, J.A.; Amonette, J.E.; Conca, J.L.; Wood, M.I.

    1993-10-01

    The objectives of this report and subsequent volumes include describing progress on (1) development of conceptual-release models for Hanford Site defense solid-waste forms; (2) optimization of experimental methods to quantify the release from contaminants from solid wastes and their subsequent interactions with unsaturated sediments; and (3) creation of empirical data for use as provisional source term and retardation factors that become input parameters for performance assessment analyses for future Hanford disposal units and baseline risk assessments for inactive and existing disposal units.

  2. Solid waste leach characteristics and contaminant-sediment interactions Volume 2: Contaminant transport under unsaturated moisture contents

    SciTech Connect

    Lindenmeier, C.W.; Serne, R.J.; Conca, J.L.

    1995-09-01

    The objectives of this report and subsequent volumes include describing progress on (1) development and optimization of experimental methods to quantify the release of contaminants from solid wastes and their subsequent interactions with unsaturated sediments and (2) the creation of empirical data that become input parameters to performance assessment (PA) analyses for future Hanford Site disposal units and baseline risk assessments for inactive and existing solid waste disposal units. For this report, efforts focused on developing methodologies to evaluate contaminant transport in Trench 8 (W-5 Burial Ground) sediments under unsaturated (vadose zone) conditions. To accomplish this task, a series of flow-through column tests were run using standard saturated column systems, Wierenga unsaturated column systems (both commercial and modified), and the Unsaturated Flow Apparatus (UFA). The reactants investigated were {sup 85}Sr, {sup 236}U, and {sup 238}U as reactive tracers, and tritium as a non-reactive tracer. Results indicate that for moderately unsaturated conditions (volumetric water contents >50 % of saturation), the Wierenga system performed reasonably well such that long water residence times (50-147 h) were achieved, and reasonably good steady-state flow conditions were maintained. The major drawbacks in using this system for reactive tracer work included (1) the inability to achieve reproducible and constant moisture content below 50% of saturation, (2) the four to six month time required to complete a single test, and (3) the propensity for mechanical failure resulting from laboratory power outages during the prolonged testing period.

  3. Remediation of Hylebos Waterway (Tacoma, WA): A common sense approach to determining contaminated sediment volumes

    SciTech Connect

    Fuglevand, P.; Revelas, G.; Striplin, B.; Striplin, P.

    1995-12-31

    Hylebos Waterway is a three mile long industrial waterway located in Commencement Bay, Washington. A CERCLA program RI/FS, conducted in the mid-1980`s, found that surface sediments (0--2 cm) were contaminated with chlorinated organics, PAHs, and metals. An ongoing pre-remedial design effort, initiated in 1993, is evaluating natural recovery and four sediment confinement options for sediments that exceed programmatic sediment quality objectives: confined aquatic disposal, near-shore disposal, upland disposal, and in-place capping. The first three confinement options require dredging of contaminated sediments which, in turn, requires accurate determination of the three dimensional distribution of contaminated sediments. To place a maximum depth boundary on the sediment sampling approach, isopach maps were created by contouring the difference between the deepest historic dredging depth and current depth along the entire waterway. These isopach maps revealed the pattern of post-industrial sediment deposition in the waterway. For example, in some areas, little or no sediment accumulation had occurred in the navigation channel. Conversely, significant accumulation had occurred along some channel edges and in near-shore areas as the result of deposition, bank sloughing and historic dredging/filling activities. The isopach maps were used to place a lower depth boundary on waterway-wide sediment contamination and to establish the maximum core sampling depth required to reach ``native`` sediments, i.e., those below the deepest historic dredging depth and believed to be uncontaminated. Subsequent geo-technical and chemical analyses of the core samples confirmed the accuracy of the isopach approach. The data generated from this sampling effort are being used to estimate the areas and volumes of subtidal sediments requiring remedial action.

  4. INTERACTIONS AMONG PHOSPHATE AMENDMENTS, MICROBES AND URANIUM MOBILITY IN CONTAMINATED SEDIMENTS

    SciTech Connect

    Knox, A

    2007-08-30

    The use of sequestering agents for the transformation of radionuclides in low concentrations in contaminated soils/sediments offers considerable potential for long-term environmental cleanup. This study evaluated the influence of four phosphate amendments and two microbial amendments on U availability. The synchrotron X-ray fluorescence mapping of the untreated U-contaminated sediment showed that U was closely associated with Mn. All tested phosphate amendments reduced aqueous U concentration more than 90%, likely due to formation of insoluble phosphate precipitates. The addition of A. piechaudii and P. putida alone were found to reduce U concentrations 63% and 31% respectively. Uranium sorption in phosphate treatments was significantly reduced in the presence of microbes. However, increased microbial activity in the treated sediment led to reduction of phosphate effectiveness. The average U concentration in 1 M MgCl{sub 2} extract from U amended sediment was 437 {micro}g/kg, but in the same sediment without microbes (autoclaved sediment), the extractable U concentration was only 103 {micro}g/kg. When the autoclaved amended sediment was treated with autoclaved biological apatite, U concentration in the 1 M MgCl{sub 2} extract was {approx}0 {micro}g/kg. Together these tests suggest that microbes may enhance U leaching and reduce phosphate amendment remedial effectiveness.

  5. Interactions among phosphate amendments, microbes and uranium mobility in contaminated sediments.

    PubMed

    Knox, Anna Sophia; Brigmon, R L; Kaplan, D I; Paller, M H

    2008-06-01

    The use of sequestering agents for the transformation of radionuclides in low concentrations in contaminated soils/sediments offers considerable potential for environmental cleanup. This study evaluated the influence of three types of phosphate (rock phosphate, biological phosphate, and calcium phytate) and two microbial amendments (Alcaligenes piechaudii and Pseudomonas putida) on U mobility. All tested phosphate amendments reduced aqueous U concentrations more than 90%, likely due to formation of insoluble phosphate precipitates. The addition of A. piechaudii and P. putida alone were found to reduce U concentrations 63% and 31%, respectively. Uranium removal in phosphate treatments was significantly reduced in the presence of the two microbes. Two sediments were evaluated in experiments on the effects of phosphate amendments on U mobility, one from a stream on the Department of Energy's Savannah River Site near Aiken, SC and the other from the Hanford Site, a Department of Energy facility in Washington state. Increased microbial activity in the treated sediment led to a reduction in phosphate effectiveness. The average U concentration in 1 M MgCl(2) extract from U contaminated sediment was 437 microg/kg, but in the same sediment without microbes (autoclaved), the extractable U concentration was only 103 microg/kg. The U concentration in the 1 M MgCl(2) extract was approximately 0 microg/kg in autoclaved amended sediment treated with autoclaved biological apatite. These results suggest that microbes may reduce phosphate amendment remedial effectiveness. PMID:18374392

  6. Contaminated Sediment Core Profiling

    EPA Science Inventory

    Evaluating the environmental risk of sites containing contaminated sediments often poses major challenges due in part to the absence of detailed information available for a given location. Sediment core profiling is often utilized during preliminary environmental investigations ...

  7. Reservoir and contaminated sediments impacts in high-Andean environments: Morphodynamic interactions with biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Escauriaza, C. R.; Contreras, M. T.; Müllendorff, D. A.; Pasten, P.; Pizarro, G. E.

    2014-12-01

    Rapid changes due to anthropic interventions in high-altitude environments, such as the Altiplano region in South America, require new approaches to understand the connections between physical and biogeochemical processes. Alterations of the water quality linked to the river morphology can affect the ecosystems and human development in the long-term. The future construction of a reservoir in the Lluta river, located in northern Chile, will change the spatial distribution of arsenic-rich sediments, which can have significant effects on the lower parts of the watershed. In this investigation we develop a coupled numerical model to predict and evaluate the interactions between morphodynamic changes in the Lluta reservoir, and conditions that can potentially desorb arsenic from the sediments. Assuming that contaminants are mobilized under anaerobic conditions, we calculate the oxygen concentration within the sediments to study the interactions of the delta progradation with the potential arsenic release. This work provides a framework for future studies aimed to analyze the complex connections between morphodynamics and water quality, when contaminant-rich sediments accumulate in a reservoir. The tool can also help to design effective risk management and remediation strategies in these extreme environments. Research has been supported by Fondecyt grant 1130940 and CONICYT/FONDAP Grant 15110017

  8. TOOLS FOR ASSESSING MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. dredging, capping, and monitored natural recovery (MNR) are the primary approaches at this time for managing contaminated sediment risks. Understanding how we...

  9. Quantifying the eroded volume of mercury-contaminated sediment using terrestrial laser scanning at Stocking Flat, Deer Creek, Nevada County, California, 2010–13

    USGS Publications Warehouse

    Howle, James F.; Alpers, Charles N.; Bawden, Gerald W.; Bond, Sandra

    2016-01-01

    High-resolution ground-based light detection and ranging (lidar), also known as terrestrial laser scanning, was used to quantify the volume of mercury-contaminated sediment eroded from a stream cutbank at Stocking Flat along Deer Creek in the Sierra Nevada foothills, about 3 kilometers west of Nevada City, California. Terrestrial laser scanning was used to collect sub-centimeter, three-dimensional images of the complex cutbank surface, which could not be mapped non-destructively or in sufficient detail with traditional surveying techniques.The stream cutbank, which is approximately 50 meters long and 8 meters high, was surveyed on four occasions: December 1, 2010; January 20, 2011; May 12, 2011; and February 4, 2013. Volumetric changes were determined between the sequential, three-dimensional lidar surveys. Volume was calculated by two methods, and the average value is reported. Between the first and second surveys (December 1, 2010, to January 20, 2011), a volume of 143 plus or minus 15 cubic meters of sediment was eroded from the cutbank and mobilized by Deer Creek. Between the second and third surveys (January 20, 2011, to May 12, 2011), a volume of 207 plus or minus 24 cubic meters of sediment was eroded from the cutbank and mobilized by the stream. Total volumetric change during the winter and spring of 2010–11 was 350 plus or minus 28 cubic meters. Between the third and fourth surveys (May 12, 2011, to February 4, 2013), the differencing of the three-dimensional lidar data indicated that a volume of 18 plus or minus 10 cubic meters of sediment was eroded from the cutbank. The total volume of sediment eroded from the cutbank between the first and fourth surveys was 368 plus or minus 30 cubic meters.

  10. A PHYSICAL, CHEMICAL, AND BIOLOGICAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, NC

    EPA Science Inventory

    Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how eff...

  11. PHYSICAL, CHEMICAL AND BIOLOGICAL TOOLS FOR EVALUATING, MONITORED NATURAL RECOVERY OF PCB CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

    EPA Science Inventory

    Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to
    manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks.
    Understanding ho...

  12. Remediation technologies for contaminated sediments

    SciTech Connect

    Swanson, L.M.

    1995-09-01

    Although soil and groundwater remediation has been conducted for many years, sediment remediation is still in its infancy. Regulatory agencies are now beginning to identify areas where contaminated sediments exist and evaluate their environmental impact. As these evaluations are completed, the projects must shift focus to how these sediments can be remediated. Also as the criteria for aquatic disposal of dredged sediments become more stringent, remediation technologies must be developed to address contaminated sediments generated by maintenance dredging.This report describes the various issues and possible technologies for sediment remediation.

  13. HANDBOOK: REMEDIATION OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Contaminated sediments may pose risks to both human and environmental health. Such sediments may be found in

    large sites, such as the harbors of industrialized ports. However, they are also frequently found in smaller sites, such as streams, lakes, bayous, and rivers. In r...

  14. GREAT LAKES CONTAMINATED SEDIMENTS PROGRAM

    EPA Science Inventory

    Contaminated sediments are a significant problem in the Great Lakes basin. Although discharges of toxic substances to the Great Lakes have been reduced in the last 20 years, persistent high concentrations of contaminants in the bottom sediments of rivers and harbors have raised...

  15. Beneficial Use Of Contaminated Sediment

    EPA Science Inventory

    The western portion of the Lake George Branch of the Indian Harbor Canal (IHC) is no longer used for commercial purposes, but contains petroleum contaminated sediments. The IHC is considered an important habitat for many animal species. Several future development projects have ...

  16. DEVELOPMENT OF ECOLOGICAL TOOLS FOR CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Contaminated sediments are of interest to a broad group of programs in the agency. OERR and the Regions are interested in monitoring contaminated sediments to characterize/assess existing conditions, determine remediation alternatives, track spatial and temporal changes, and dete...

  17. A MULTI-ORD LAB AND REGIONAL ASSESSMENT OF MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC

    EPA Science Inventory

    Management of contaminated sediments poses many challenges due to varied contaminants and volumes of sediments to manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks. Understanding how well the ...

  18. Remediation technologies for oil-contaminated sediments.

    PubMed

    Agarwal, Ashutosh; Liu, Yu

    2015-12-30

    Oil-contaminated sediments pose serious environmental hazards for both aquatic and terrestrial ecosystems. Innovative and environmentally compatible technologies are urgently required to remove oil-contaminated sediments. In this paper, various physical, chemical and biological technologies are investigated for the remediation of oil-contaminated sediments such as flotation and washing, coal agglomeration, thermal desorption, ultrasonic desorption, bioremediation, chemical oxidation and extraction using ionic liquids. The basic principles of these technologies as well as their advantages and disadvantages for practical application have been discussed. A combination of two or more technologies is expected to provide an innovative solution that is economical, eco-friendly and adaptable. PMID:26414316

  19. Contaminated sediment dynamics in peatland headwaters

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Clay, Gareth; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2016-04-01

    Peatlands are an important store of soil carbon, provide multiple ecosystem services, and when located in close proximity to urban and industrial areas, can also act as sinks of atmospherically deposited heavy metals. The near-surface layer of the blanket peats of the Peak District National Park, UK, is severely contaminated with high concentrations of anthropogenically derived, atmospherically deposited lead (Pb). These peats are severely degraded, and there is increasing concern that erosion is releasing considerable quantities of this legacy pollution into surface waters. Despite substantial research into Pb dynamics in peatlands formal description of the possible mechanisms of contaminated sediment mobilisation is limited. However, there is evidence to suggest that a substantial proportion of contaminated surface sediment may be redistributed elsewhere in the catchment. This study uses the Pb contamination stored near the peat's surface as a fingerprint to trace contaminated sediment dynamics and storage in three severely degraded headwater catchments. Erosion is exposing high concentrations of Pb on interfluve surfaces, and substantial amounts of reworked contaminated material are stored on other catchment surfaces (gully walls and floors). We propose a variety of mechanisms as controls of Pb release and storage on the different surfaces, including: (i) wind action on interfluves; (ii) the aspect of gully walls, and (iii) gully depth. Vegetation also plays an important role in retaining contaminated sediment on all surfaces.

  20. Ocean acidification increases the toxicity of contaminated sediments.

    PubMed

    Roberts, David A; Birchenough, Silvana N R; Lewis, Ceri; Sanders, Matthew B; Bolam, Thi; Sheahan, Dave

    2013-02-01

    Ocean acidification (OA) may alter the behaviour of sediment-bound metals, modifying their bioavailability and thus toxicity. We provide the first experimental test of this hypothesis with the amphipod Corophium volutator. Amphipods were exposed to two test sediments, one with relatively high metals concentrations (Σmetals 239 mg kg(-1) ) and a reference sediment with lower contamination (Σmetals 82 mg kg(-1) ) under conditions that mimic current and projected conditions of OA (390-1140 μatm pCO2 ). Survival and DNA damage was measured in the amphipods, whereas the flux of labile metals was measured in the sediment and water column (WC) using Diffusive Gradients in Thin-films. The contaminated sediments became more acutely toxic to C. volutator under elevated pCO2 (1140 μatm). There was also a 2.7-fold increase in DNA damage in amphipods exposed to the contaminated sediment at 750 μatm pCO2 , as well as increased DNA damage in organisms exposed to the reference sediment, but only at 1140 μatm pCO2 . The projected pCO2 concentrations increased the flux of nickel and zinc to labile states in the WC and pore water. However, the increase in metal flux at elevated pCO2 was equal between the reference and contaminated sediments or, occasionally, greater from reference sediments. Hence, the toxicological interaction between OA and contaminants could not be explained by e ffects of pH on metal speciation. We propose that the additive physiological effects of OA and contaminants will be more important than changes in metal speciation in determining the responses of benthos to contaminated sediments under OA. Our data demonstrate clear potential for near-future OA to increase the susceptibility of benthic ecosystems to contaminants. Environmental policy should consider contaminants within the context of changing environmental conditions. Specifically, sediment metals guidelines may need to be reevaluated to afford appropriate environmental protection under future

  1. USING SPMDS TO ACCESS MANAGMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Dredging, in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an appropria...

  2. GEOELECTRICAL EVIDENCE OF MICROBIAL DEGRADATION OF DIESEL CONTAMINATED SEDIMENTS

    EPA Science Inventory

    The alteration of physical properties by microbial activity in petroleum contaminated sediments was investigated using geophysical techniques in laboratory column experiments. Microbial population growth was determined by the Most Probable Number technique (MPN), community dynami...

  3. USING SPMDS TO ACCESS MANAGEMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Dredging, in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an appropria...

  4. USING SPMDS TO ASSESS MANAGEMENT STRATEGIES FOR PCB CONTAMINATED SEDIMENTS.

    EPA Science Inventory

    Abstract: Dredging in-place treatment, capping and monitored natural recovery, used together or separately are the primary approaches for managing contaminated sediment risks. Understanding how well different approaches work in different environments is critical for choosing an...

  5. NATIONAL CONFERENCE ON MANAGEMENT AND TREATMENT OF CONTAMINATED SEDIMENTS: PROCEEDINGS

    EPA Science Inventory

    The National Conference on Management and Treatment of Contaminated Sediment was held in Cincinnati, OH, May 13 to 14, 1997. This technology transfer meeting was held for 213 professionals from various EPA divisions and other organizations, including Environment Canada, the U.S. ...

  6. NHEERL CONTAMINATED SEDIMENT RESEARCH MULTI-YEAR IMPLEMENTATION PLAN (2005)

    EPA Science Inventory

    ORD has developed a multi-year plan (MYP) called the Contaminated Sites MYP to address the research needs of EPA's Office of Superfund Remediation and Technology Innovation (OSRTI). One of the long-term goals of the Contaminated Sites MYP relates to contaminated sediments, and t...

  7. Mixture design and treatment methods for recycling contaminated sediment.

    PubMed

    Wang, Lei; Kwok, June S H; Tsang, Daniel C W; Poon, Chi-Sun

    2015-01-01

    Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO2 curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO2 (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources. PMID:25464304

  8. Innovative Capping Technology To Prevent The Migration of Toxic Chemicals From Contaminated Sediments

    EPA Science Inventory

    Capping is a common strategy for decreasing the risk associated with contaminated sediments in lakes and streams. Historically, caps have been designed to physically isolate contaminated sediments and prevent the transport of contaminants from sediments into the water above them...

  9. Influence of sediment storage on downstream delivery of contaminated sediment

    USGS Publications Warehouse

    Malmon, D.V.; Reneau, S.L.; Dunne, T.; Katzman, D.; Drakos, P.G.

    2005-01-01

    Sediment storage in alluvial valleys can strongly modulate the downstream migration of sediment and associated contaminants through landscapes. Traditional methods for routing contaminated sediment through valleys focus on in-channel sediment transport but ignore the influence of sediment exchanges with temporary sediment storage reservoirs outside the channel, such as floodplains. In theory, probabilistic analysis of particle trajectories through valleys offers a useful strategy for quantifying the influence of sediment storage on the downstream movement of contaminated sediment. This paper describes a field application and test of this theory, using 137Cs as a sediment tracer over 45 years (1952-1997), downstream of a historical effluent outfall at the Los Alamos National Laboratory (LANL), New Mexico. The theory is parameterized using a sediment budget based on field data and an estimate of the 137Cs release history at the upstream boundary. The uncalibrated model reasonably replicates the approximate magnitude and spatial distribution of channel- and floodplain-stored 137Cs measured in an independent field study. Model runs quantify the role of sediment storage in the long-term migration of a pulse of contaminated sediment, quantify the downstream impact of upstream mitigation, and mathematically decompose the future 137Cs flux near the LANL property boundary to evaluate the relative contributions of various upstream contaminant sources. The fate of many sediment-bound contaminants is determined by the relative timescales of contaminant degradation and particle residence time in different types of sedimentary environments. The theory provides a viable approach for quantifying the long-term movement of contaminated sediment through valleys. Copyright 2005 by the American Geophysical Union.

  10. Mercury contaminated sediment sites—An evaluation of remedial options

    SciTech Connect

    Randall, Paul M.; Chattopadhyay, Sandip

    2013-08-15

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to methylmercury (MeHg). Consequently, Hg in historically-contaminated sediments can result in high levels of significant exposure for aquatic species, wildlife and human populations consuming fish. Even if source control of contaminated wastewater is achievable, it may take a very long time, perhaps decades, for Hg-contaminated aquatic systems to reach relatively safe Hg levels in both water and surface sediment naturally. It may take even longer if Hg is present at higher concentration levels in deep sediment. Hg contaminated sediment results from previous releases or ongoing contributions from sources that are difficult to identify. Due to human activities or physical, chemical, or biological processes (e.g. hydrodynamic flows, bioturbation, molecular diffusion, and chemical transformation), the buried Hg can be remobilized into the overlying water. Hg speciation in the water column and sediments critically affect the reactivity (i.e. conversion of inorganic Hg(II) to MeHg), transport, and its exposure to living organisms. Also, geochemical conditions affect the activity of methylating bacteria and its availability for methylation. This review paper discusses remedial considerations (e.g. key chemical factors in fate and transport of Hg, source characterization and control, environmental management procedures, remediation options, modeling tools) and includes practical case studies for cleaning up Hg-contaminated sediment sites. -- Highlights: ► Managing mercury-contaminated sediment sites are challenging to remediate. ► Remediation technologies are making a difference in managing these sites. ► Partitioning plays a dominant role in the distribution of mercury species. ► Mathematical

  11. Active capping technology: a new environmental remediation of contaminated sediment.

    PubMed

    Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

    2016-03-01

    The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented. PMID:26762937

  12. Toxicity of lead-contaminated sediment to mute swans.

    PubMed

    Day, D D; Beyer, W N; Hoffman, D J; Morton, A; Sileo, L; Audet, D J; Ottinger, M A

    2003-05-01

    Most ecotoxicological risk assessments of wildlife emphasize contaminant exposure through ingestion of food and water. However, the role of incidental ingestion of sediment-bound contaminants has not been adequately appreciated in these assessments. This study evaluates the toxicological consequences of contamination of sediments with metals from hard-rock mining and smelting activities. Lead-contaminated sediments collected from the Coeur d'Alene River Basin in Idaho were combined with either a commercial avian maintenance diet or ground rice and fed to captive mute swans (Cygnus olor) for 6 weeks. Experimental treatments consisted of maintenance or rice diets containing 0, 12 (no rice group), or 24% highly contaminated (3,950 microg/g lead) sediment or 24% reference (9.7 microg/g lead) sediment. Although none of the swans died, the group fed a rice diet containing 24% lead-contaminated sediment were the most severely affected, experiencing a 24% decrease in mean body weight, including three birds that became emaciated. All birds in this treatment group had nephrosis; abnormally dark, viscous bile; and significant (p contaminated sediments. All swans fed diets that contained 24% lead-contaminated sediment had renal acid-fast intranuclear inclusion bodies, which are diagnostic of lead

  13. Microscopic reactive diffusion of uranium in the contaminated sediments at Hanford, United States

    NASA Astrophysics Data System (ADS)

    Liu, Chongxuan; Zachara, John M.; Yantasee, Wassana; Majors, Paul D.; McKinley, James P.

    2006-12-01

    Microscopic and spectroscopic analyses of uranium-contaminated sediments from select locations at the U.S. Department of Energy (DOE) Hanford site have revealed that sorbed uranium (U) often exists as uranyl precipitates associated with intragrain fractures of granitic clasts. The release of U to contacting fluids appears to be controlled by intragrain ion diffusion coupled with the dissolution kinetics of the precipitates that exist in the form of Na-boltwoodite. Here we present a coupled microscopic reactive diffusion model for the contaminated sediment on the basis of experimental measurements of intragrain diffusivity in the granitic lithic fragments and the dissolution kinetics of synthetic Na-boltwoodite. Nuclear magnetic resonance, pulse gradient spin echo measurements showed that the intragrain fractures of the granitic clasts isolated from the sediment contained two domains with distinct diffusivities. The fast diffusion domain had an apparent tortuosity of 1.5, while that of the slow region was two orders of magnitude larger. A two-domain diffusion model was assembled and used to infer the geochemical conditions that led to intragrain uranyl precipitation during waste-sediment interaction. Rapid precipitation of Na-boltwoodite was simulated with an alkaline U-containing, high-carbonate tank waste solution that diffused into intragrain fractures, which originally contained Si-rich pore water in equilibrium with feldspar grains in the lithic fragments. The model was also used to simulate uranyl dissolution and release from contaminated sediment to recharge waters. With independently characterized parameters for Na-boltwoodite dissolution, the model simulations demonstrated that diffusion could significantly decrease the rates of intragrain uranyl mineral dissolution due to diffusion-induced local solubility limitation with respect to Na-boltwoodite.

  14. Simulation of contaminated sediment transport in White Oak Creek basin

    SciTech Connect

    Bao, Y.; Clapp, R.B.; Brenkert, A.L.; Moore, T.D.; Fontaine, T.A.

    1995-12-31

    This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ({sup 137}Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of {sup 137}Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies.

  15. Contaminated sediment removal from a spent fuel storage canal

    SciTech Connect

    Geber, K R

    1993-01-01

    A leaking underground spent fuel transfer canal between a decommissioned reactor and a radiochemical separations building at the Oak Ridge National Laboratory (ORNL) was found to contain RCRA-hazardous and radioactive sediment. Closure of the Part B RCRA permitted facility required the use of an underwater robotic vacuum and a filtration-containment system to separate and stabilize the contaminated sediment. This paper discusses the radiological controls established to maintain contamination and exposures As Low As Reasonably Achievable (ALARA) during the sediment removal.

  16. Volatilization of extensively dechlorinated polychlorinated biphenyls from historically contaminated sediments

    SciTech Connect

    Bushart, S.P.; Bush, B.; Barnard, E.L.; Bott, A. |

    1998-10-01

    A study was conducted as a preliminary characterization of the ability of polychlorinated biphenyl (PCB)-contaminated sediments to volatilize PCBs into the air upon drying under conditions meant to be environmentally relevant. Sediments collected from the St. Lawrence River contained high levels of PCBs. The PCB contamination consisted of high levels of mainly ortho-substituted mono- and dichlorobiphenyls, suggesting that the original contamination had been transformed by microbial reductive dechlorination. These sediments lost 0.07 to 1.7% of their total PCB content to the air during a 24-h drying cycle. Sediments with varying amounts of overlying water lost significantly less PCB to the air within the first few cycles than native sediments with no overlying water. Losses due to PCB volatilization were well correlated to sediment PCB concentration and water loss but not to drying temperatures (4--43 C) within 24-h drying cycles. The PCB congeners representing >90% of those volatilized within the first 24 h of drying were those produced in the sediment samples as a result of microbial reductive dechlorination of the original PCB contamination. The presence of these congeners in volatilized air samples was positively confirmed by gas chromatography-mass spectrometry with Fourier transform infrared detection (FTIR). These results strongly suggest that significant amounts of mono-, di-, and trichlorobiphenyls may be volatilized from PCB-contaminated sediments at ambient environmental conditions and that this PCB volatilization may be enhanced by microbial reductive dechlorination.

  17. IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS - ACTIVE CAPPING TECHNOLOGY

    SciTech Connect

    Knox, A.; Roberts, J.; Paller, M.; Reible, D.

    2010-09-02

    Active capping is a relatively new approach for treating contaminated sediments. It involves applying chemically reactive amendments to the sediment surface. The main role of active caps is to stabilize contaminants in contaminated sediments, lower the bioavailable pool of contaminants, and reduce the release of contaminants to the water column. Metals are common contaminants in many marine and fresh water environments as a result of industrial and military activities. The mobile, soluble forms of metals are generally considered toxic. Induced chemical precipitation of these metals can shift toxic metals from the aqueous phase to a solid, precipitated phase which is often less bioavailable. This approach can be achieved through application of sequestering agents such as rock phosphates, organoclays, zeolites, clay minerals, and biopolymers (e.g., chitosan) in active capping technology. Active capping holds great potential for a more permanent solution that avoids residual risks resulting from contaminant migration through the cap or breaching of the cap. In addition to identifying superior active capping agents, research is needed to optimize application techniques, application rates, and amendment combinations that maximize sequestration of contaminants. A selected set of active capping treatment technologies has been demonstrated at a few sites, including a field demonstration at the Savannah River Site, Aiken, SC. This demonstration has provided useful information on the effects of sequestering agents on metal immobilization, bioavailability, toxicity, and resistance to mechanical disturbance.

  18. Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

    PubMed

    Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. PMID:26140749

  19. Contaminated sediments database for the Gulf of Maine

    USGS Publications Warehouse

    Buchholtz ten Brink, M. R.; Manheim, F. T.; Mecray, E.L.; Hastings, M.E.; Currence, J.M.; Farrington, J.W.; Jones, S.H.; Larsen, P.F.; Tripp, B.W.; Wallace, G.T., Jr.; Ward, L.G.; Fredette, T.J.; Liebman, M.L.; Smith Leo, W.

    2002-01-01

    Bottom sediments in the Gulf of Maine and its estuaries have accumulated pollutants of many types, including metals and organic compounds of agricultural, industrial, and household derivation. Much analytical and descriptive data has been obtained on these sediments over the past decades, but only a small effort had been made, prior to this project, to compile and edit the published and unpublished data in forms suitable for a variety of users. The Contaminated Sediments Database for the Gulf of Maine provides a compilation and synthesis of existing data to help establish the environmental status of our coastal sediments and the transport paths and fate of contaminants in this region. This information, in turn, forms one of the essential bases for developing successful remediation and resource management policies.

  20. Passive sampling methods for contaminated sediments: risk assessment and management.

    PubMed

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-04-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree ), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal ) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree ) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. PMID

  1. Mapping and monitoring contaminated-sediment geometry and stability.

    PubMed

    Rukavina, N

    2001-02-01

    Environment Canada's National Water Research Institute (NWRI) conducts research on freshwater contaminated sediments, much of which is focused on designated areas of concern in the Great Lakes and their connecting channels. This paper reviews new acoustic and video equipment and procedures developed to map the geometry and stability of the sediments, and describes their applications. A RoxAnn acoustic seabed-classification system is used for mapping bottom-sediment types and locating the deposits of fine-grained sediments with which contaminants are associated. The system uses the acoustic properties of sediments to distinguish textural types ranging from mud to boulders, and displays the data as they are collected. The sediment thickness is measured with a weighted video-acoustic tripod which is lowered into the sediments to refusal, and which recorded penetration with a video camera or an echosounder transducer. The stability of the contaminated sediments was monitored with a bottom-mounted, high-precision echo sounder-digitizer, which logs changes in the position of the sediment-water interface produced by erosion or deposition. The same procedure can be used in capping or dredging projects to track bottom changes as they occur, or they can be measured by pre- and post-project mapping of bathymetry and morphology with sweep-sonar or side-scan sonar equipment. The new equipment and procedures have been successfully applied to a number of areas of concern in the Great Lakes basin. They provide a faster and more detailed characterization of sediment properties and geometry than was previously available, and have been particularly effective in optimizing sampling surveys and monitoring remediation projects. PMID:11258831

  2. Passive sampling methods for contaminated sediments: Risk assessment and management

    PubMed Central

    Greenberg, Marc S; Chapman, Peter M; Allan, Ian J; Anderson, Kim A; Apitz, Sabine E; Beegan, Chris; Bridges, Todd S; Brown, Steve S; Cargill, John G; McCulloch, Megan C; Menzie, Charles A; Shine, James P; Parkerton, Thomas F

    2014-01-01

    This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision making at multiple points in the process of assessing and managing contaminated sediment sites. PSMs can increase certainty in site investigation and management, because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal) for 4 key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures). The use of passive sampling devices (PSDs) presents challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with PSMs and considering appropriate spatial scales to meet study objectives. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants, identifying and evaluating contaminant source contributions, calibrating site-specific models, and, improving weight-of-evidence based decision frameworks. PSM data can be used to assist in delineating sediment management zones based on likelihood of exposure effects, monitor remedy effectiveness, and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse after management actions. Examples are provided illustrating why PSMs and freely dissolved contaminant concentrations (Cfree) should be incorporated into contaminated sediment investigations and study designs to better focus on and understand contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr

  3. BIOLOGICAL REMEDIATION OF CONTAMINATED SEDIMENTS, WITH SPECIAL EMPHASIS ON THE GREAT LAKES

    EPA Science Inventory

    These proceedings describe a workshop at which biological remediation of contaminated sediments was discussed. or the purpose of the workshop, contaminated sediments of primary interest were those within six of the Areas of Concern (AOC) identified in the U.S./Canada Internationa...

  4. Uranium phases in contaminated sediments below Hanford's U tank farm.

    PubMed

    Um, Wooyong; Wang, Zheming; Serne, R Jeffrey; Williams, Benjamin D; Brown, Christopher F; Dodge, Cleveland J; Francis, Arokiasamy J

    2009-06-15

    Macroscopic and spectroscopic investigations (XAFS, XRF, and TRLIF) on Hanford contaminated vadose zone sediments from the U-tank farm showed that U(VI) exists as different surface phases as a function of depth below ground surface (bgs). Secondary precipitates of U(VI) silicate precipitates (boltwoodite and uranophane) were present dominantly in shallow-depth sediments (15-16 m bgs), while adsorbed U(VI) phases and polynuclear U(VI) surface precipitates were considered to dominate in intermediate-depth sediments (20-25 m bgs). Only natural uranium was observed in the deeper sediments (> 28 m bgs) with no signs of contact with tank wastes containing Hanford-derived U(VI). Across all depths, most of the U(VI) was preferentially associated with the silt and clay size fractions of sediments. Strong correlation between U(VI) and Ca was found in the shallow-depth sediments, especially for the precipitated U(VI) silicates. Because U(VI) silicate precipitates dominate in the shallow-depth sediments, the released U(VI) concentration by macroscopic (bi)carbonate leaching resulted from both desorption and dissolution processes. Having different U(VI) surface phases in the Hanford contaminated sediments indicates that the U(VI) release mechanism could be complicated and that detailed characterization of the sediments using several different methods would be needed to estimate U(VI) fate and transport correctly in the vadose zone. PMID:19603635

  5. Uranium Phases in Contaminated Sediments Below Hanford's U Tank Farm

    SciTech Connect

    Um, Wooyong; Wang, Zheming; Serne, R. Jeffrey; Williams, Benjamin D.; Brown, Christopher F.; Dodge, Cleveland J.; FRANCIS, AROKIASAMY J.

    2009-06-11

    Macroscopic and spectroscopic investigations (XAFS, XRF and TRLIF) on Hanford contaminated vadose zone sediments from the U-tank farm showed that U(VI) exists as different surface phases as a function of depth below ground surface (bgs). Dominant U(VI) silicate precipitates (boltwoodite and uranophane) were present in shallow-depth sediments (15-16 m bgs). In the intermediate depth sediments (20-25 m bgs), adsorbed U(VI) phases dominated but small amounts of surface precipitates consisting of polynuclear U(VI) surface complex were also identified. The deep depth sediments (> 28 m bgs) showed no signs of contact with tank wastes containing Hanford-derived U(VI), but natural uranium solid phases were observed. Most of the U(VI) was preferentially associated with the silt and clay size fractions and showed strong correlation with Ca, especially for the precipitated U(VI) silicate phase in the shallow depth sediments. Because U(VI) silicate precipitates dominate the U(VI) phases in the shallow depth sediments, macroscopic (bi)carbonate leaching should result in U(VI) releases from both desorption and dissolution processes. Having several different U(VI) surface phases in the Hanford contaminated sediments indicates that the U(VI) release mechanism could be complicated and that detailed characterization of the sediments would be needed to estimate U(VI) fate and transport in vadose zone.

  6. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

    Valsaraj, K.T.; Ravikrishna, R.; Reible, D.D.; Thibodeaux, L.J.; Choy, B.; Price, C.B.; Brannon, J.M.; Myers, T.E.; Yost, S.

    1999-01-01

    The sediment-to-air fluxes of two polycyclic aromatic hydrocarbons (phenanthrene and pyrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) from a laboratory-contaminated sediment and those of three polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, and pyrene) from three field sediments were investigated in experimental microcosms. The flux was dependent on the sediment moisture content, air-filled porosity, and the relative humidity of the air flowing over the sediment surface. The mathematical model predictions of flux from the laboratory-spiked sediment agreed with observed values. The fluxes of compounds with higher hydrophobicity were more air-side resistance controlled. Conspicuous differences were observed between the fluxes from the laboratory-spiked and two of the three field sediments. Two field sediments showed dramatic increases in mass-transfer resistances with increasing exposure time and had significant fractions of oil and grease. The proposed mathematical model was inadequate for predicting the flux from the latter field sediments. Sediment reworking enhanced the fluxes from the field sediments due to exposure of fresh solids to the air. Variations in flux from the lab-spiked sediment as a result of change in air relative humidity were due to differences in retardation of chemicals on a dry or wet surface sediment. High moisture in the air over the dry sediment increased the competition for sorption sites between water and contaminant and increased the contaminant flux.

  7. Electro-bioremediation of contaminated sediment by electrode enhanced capping.

    PubMed

    Yan, Fei; Reible, Danny

    2015-05-15

    In-situ capping often eliminates or slows natural degradation of hydrocarbon due to the reducing conditions in the sediments. The purpose of this research was to demonstrate a reactive capping technique, an electrode enhanced cap, to produce favorable conditions for hydrocarbon degradation and evaluate this reactive capping technique for contaminated sediment remediation. Two graphite electrodes were placed horizontally at different layers in a cap and connected to external power of 2 V. Redox potentials increased and pH decreased around the anode. Phenanthrene concentration decreased and PAH degradation genes increased in the vicinity of the anode. Phenanthrene concentrations at 0-1 cm sediment beneath the anode decreased to ∼50% of initial concentration over ∼70 days, while phenanthrene levels in control reactor kept unchanged. A degradation model of electrode enhanced capping was developed to simulate reaction-diffusion processes, and model results show that a reaction-dominated region was created in the vicinity of the anode. Although the degradation dominated region was thin, transport processes in a sediment cap environment are typically sufficiently slow to allow this layer to serve as a permeable reactive barrier for hydrocarbon decontamination. PMID:25819321

  8. DEVELOPING TOOLS FOR MONITORED NATURAL RECOVERY OF PCB-CONTAMINATED SEDIMENTS AT LAKE HARTWELL, SC

    EPA Science Inventory

    Contaminated sediments pose a risk to human health and the environment . The management of this risk is currently limited practically to three technologies: dredging, capping, and natural recovery. Monitored natural recovery relies on the natural burial and removal mechanisms to...

  9. UPTAKE AND DEPURATION OF ORGANIC CONTAMINANTS BY BLUE MUSSELS (MYTILUS EDULIS) EXPOSED TO ENVIRONMENTALLY CONTAMINATED SEDIMENT

    EPA Science Inventory

    Experiments were designed to expose blue mussels (Mytilus edulis) to contaminated sediment collected from Narragansett Bay, Rhode Island, USA in 1982. Measurements were taken to allow comparisons of the uptake and depuration of polycyclic aromatic hydrocarbons (PAHs) and polychlo...

  10. EVALUATION OF BIOAEROSOL COMPONENTS, GENERATION FACTORS, AND AIRBORNE TRANSPORT ASSOCIATED WITH LIME TREATMENT OF CONTAMINATED SEDIMENT

    EPA Science Inventory

    Lime treatment has been used in contaminated sediment management activities for many purposes such as dewatering, improvement of physical properties, and reducing contaminant mobility. Exothermic volatilization of volatile organic compounds from lime-treated sediment is well kno...

  11. Selecting Performance Reference Compounds (PRCS)for Polyethylene Passive Samplers Deployed at Contaminated Sediment Sites

    EPA Science Inventory

    Use of equilibrium passive samplers for performing aquatic environmental monitoring at contaminated sediment sites, including Superfund sites, is becoming more common. However, a current challenge in passive sampling is determining when equilibrium is achieved between the sampl...

  12. The value of information for managing contaminated sediments.

    PubMed

    Bates, Matthew E; Sparrevik, Magnus; de Lichy, Nicolas; Linkov, Igor

    2014-08-19

    Effective management of contaminated sediments is important for long-term human and environmental health, but site-management decisions are often made under high uncertainty and without the help of structured decision support tools. Potential trade-offs between remedial costs, environmental effects, human health risks, and societal benefits, as well as fundamental differences in stakeholder priorities, complicate decision making. Formal decision-analytic tools such as multicriteria decision analysis (MCDA) move beyond ad hoc decision support to quantitatively and holistically rank management alternatives and add transparency and replicability to the evaluation process. However, even the best decisions made under uncertainty may be found suboptimal in hindsight, once additional scientific, social, economic, or other details become known. Value of information (VoI) analysis extends MCDA by systematically evaluating the impact of uncertainty on a decision. VoI prioritizes future research in terms of expected decision relevance by helping decision makers estimate the likelihood that additional information will improve decision confidence or change their selection of a management plan. In this study, VoI analysis evaluates uncertainty, estimates decision confidence, and prioritizes research to inform selection of a sediment capping strategy for the dibenzo-p-dioxin and -furan contaminated Grenland fjord system in southern Norway. The VoI model extends stochastic MCDA to model decisions with and without simulated new information and compares decision confidence across scenarios with different degrees of remaining uncertainty. Results highlight opportunities for decision makers to benefit from additional information by anticipating the improved decision confidence (or lack thereof) expected from reducing uncertainties for each criterion or combination of criteria. This case study demonstrates the usefulness of VoI analysis for environmental decisions by predicting when

  13. Effects of lead-contaminated sediment on Rana sphenocephala tadpoles

    USGS Publications Warehouse

    Sparling, D.W.; Krest, S.K.; Ortiz-Santaliestra, M.

    2006-01-01

    We exposed larval southern leopard frogs (Rana sphenocephala) to lead-contaminated sediments to determine the lethal and sublethal effects of this metal. Tadpoles were laboratory-raised from early free-swimming stage through metamorphosis at lead concentrations of 45, 75, 180, 540, 2360, 3940, 5520, and 7580 mg/kg dry weight in sediment. Corresponding pore water lead concentrations were 123, 227, 589, 1833, 8121, 13,579, 19,038, and 24,427 ug/L. Tadpoles exposed to lead concentrations in sediment of 3940 mg/kg or higher died within 2 to 5 days of exposure. At lower concentrations, mortality through metamorphosis ranged from 3.5% at 45 mg/kg lead to 37% at 2360 mg/kg lead in sediment. The LC50 value for lead in sediment was 3728 mg/kg (95% CI=1315 to 72,847 mg/kg), which corresponded to 12,539 ug/L lead in pore water (95% CI= 4000 to 35,200 ug/L). Early growth and development were depressed at 2,360 mg/kg lead in sediment (8100 ug/L in pore water) but differences were not evident by the time of metamorphosis. The most obvious effect of lead was its pronounced influence on skeletal development. Whereas tadpoles at 45 mg/kg lead in sediment did not display permanent abnormalities, skeletal malformations increased in frequency and severity at all higher lead concentrations. By 2360 mg/kg, 100% of surviving metamorphs displayed severe spinal problems, reduced femur and humerus lengths, deformed digits, and other bone malformations. Lead concentrations in tissues correlated positively with sediment and pore water concentrations.

  14. Developmental toxicity of lead contaminated sediment to mallard ducks

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  15. Developmental toxicity of lead-contaminated sediment to mallard ducklings

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Sileo, L.; Audet, D.J.; Campbell, J.K.; LeCaptain, L.J.

    2000-01-01

    Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

  16. The Volume Field Model about Strong Interaction and Weak Interaction

    NASA Astrophysics Data System (ADS)

    Liu, Rongwu

    2016-03-01

    For a long time researchers have believed that strong interaction and weak interaction are realized by exchanging intermediate particles. This article proposes a new mechanism as follows: Volume field is a form of material existence in plane space, it takes volume-changing motion in the form of non-continuous motion, volume fields have strong interaction or weak interaction between them by overlapping their volume fields. Based on these concepts, this article further proposes a ``bag model'' of volume field for atomic nucleus, which includes three sub-models of the complex structure of fundamental body (such as quark), the atom-like structure of hadron, and the molecule-like structure of atomic nucleus. This article also proposes a plane space model and formulates a physics model of volume field in the plane space, as well as a model of space-time conversion. The model of space-time conversion suggests that: Point space-time and plane space-time convert each other by means of merging and rupture respectively, the essence of space-time conversion is the mutual transformations of matter and energy respectively; the process of collision of high energy hadrons, the formation of black hole, and the Big Bang of universe are three kinds of space-time conversions.

  17. Monitoring and modeling contaminated sediment transport in the White Oak Creek watershed

    SciTech Connect

    Fontaine, T.A.

    1991-11-01

    Over the past 47 years, operations and waste disposal activities at Oak Ridge National Laboratory have resulted in the contamination of the White Oak Creek drainage system. The containments presenting the highest risk to human health and the environment are particle reactive and are associated with the soils and sediments in White Oak Creek. During floods, the erosion of these sediments results in the transport of contaminants out of the catchment into the Clinch River. A long-term strategy is required to monitor the movement of contaminated sediments and to predict the transport of these sediments that could occur during major floods. A monitoring program will provide the information required to (1) evaluate the existing off-site transport of contaminated sediments, (2) evaluate the need for short-term control measures, (3) set priorities for remediation of contaminated areas in White Oak Creek (4) verify the success of completed remedial actions intended to control the movement of contaminated sediments, and (5) develop a computer model to simulate the transport of contaminated sediments in White Oak Creek. A contaminant-transport model will be developed to (1) evaluate the potential for the off-site transport of contaminated sediments during major floods, (2) develop long term control measures and remediation solutions, (3) predict the impact of future land-use changes in White Oak Creek on the transport of contaminated sediment. This report contains a plan for the monitoring and modeling activities required to accomplish these objectives.

  18. Monitoring and modeling contaminated sediment transport in the White Oak Creek watershed. Environmental Restoration Program

    SciTech Connect

    Fontaine, T.A.

    1991-11-01

    Over the past 47 years, operations and waste disposal activities at Oak Ridge National Laboratory have resulted in the contamination of the White Oak Creek drainage system. The containments presenting the highest risk to human health and the environment are particle reactive and are associated with the soils and sediments in White Oak Creek. During floods, the erosion of these sediments results in the transport of contaminants out of the catchment into the Clinch River. A long-term strategy is required to monitor the movement of contaminated sediments and to predict the transport of these sediments that could occur during major floods. A monitoring program will provide the information required to (1) evaluate the existing off-site transport of contaminated sediments, (2) evaluate the need for short-term control measures, (3) set priorities for remediation of contaminated areas in White Oak Creek (4) verify the success of completed remedial actions intended to control the movement of contaminated sediments, and (5) develop a computer model to simulate the transport of contaminated sediments in White Oak Creek. A contaminant-transport model will be developed to (1) evaluate the potential for the off-site transport of contaminated sediments during major floods, (2) develop long term control measures and remediation solutions, (3) predict the impact of future land-use changes in White Oak Creek on the transport of contaminated sediment. This report contains a plan for the monitoring and modeling activities required to accomplish these objectives.

  19. Inhibition Effect of Secondary Phosphate Mineral Precipitation on Uranium Release from Contaminated Sediments

    SciTech Connect

    Shi, Zhenqing; Liu, Chongxuan; Zachara, John M.; Wang, Zheming; Deng, Baolin

    2009-11-01

    The inhibitory effect of phosphate mineral precipitation on uranium release was evaluated using a U(VI)-contaminated sediment collected from the US Department of Energy (DOE) Hanford site. The sediment contained U(VI) that was associated with diffusion-limited intragrain regions within its mm-size granitic lithic fragments. The sediment was first treated to promote phosphate mineral precipitation in batch suspensions spiked with 1 and 50 mM aqueous phosphate, and calcium in a stoichiometric ratio of mineral hydroxyapatite. The phosphate-treated sediment was then leached to solubilize contaminant U(VI) in a column system using a synthetic groundwater that contained chemical components representative of Hanford groundwater. Phosphate treatment significantly decreased the extent of U(VI) release from the sediment. Within the experimental duration of about 200 pore volumes, the effluent U(VI) concentrations were consistently lower by over one and two orders of magnitude after the sediment was treated with 1 and 50 mM of phosphate, respectively. Measurements of solid phase U(VI) using various spectroscopes and chemical extraction of the sediment collectively indicated that the inhibition of U(VI) release from the sediment was caused by: 1) U(VI) adsorption to the secondary phosphate precipitates and 2) the transformation of initially present U(VI) mineral phases to less soluble forms.

  20. Contaminated sediments: Lectures on environmental aspects of particle-associated chemicals in aquatic systems

    SciTech Connect

    Forstner, U.

    1989-01-01

    Sediments are increasingly recognized as both a carrier and a possible source of contaminants in aquatic systems. Since the early part of the century, limnological research on eutrophication problems and acidification indicated that particle-interactions can affect aquatic ecosystems. In contrast to the eutrophication and acidification problems, research on toxic chemicals has included sediment aspects from its beginning. In the lecture notes, following the description of priority pollutants related to sedimentary phases, four aspects were covered, which in an overlapping succession also reflect the development of knowledge in particle-associated pollutants during the past 25 years: the identification, surveillance, monitoring and control of sources and distribution of pollutants; the evaluation of solid/solution relations of contaminants in surface waters; the study of in-situ processes and mechanisms in pollutant transfer in various compartments of the aquatic ecosystems and, the assessment of the environmental impact of particle-bound contaminants. The last chapter focuses on dredged materials, including their disposal and the treatment of strongly contaminated sediments. Cases studies include the Niagara River/Lake Ontario pollution; solid speciation of metals in river sediments; the Rhine River; Puget Sound; Rotterdam Harbor; and the mobilization of cadmium from tidal river sediments.

  1. Geoelectrical Evidence of Microbial Degradation of Diesel Contaminated Sediments

    NASA Astrophysics Data System (ADS)

    Werkema, D. D.; Atekwana, E. A.; Rossbach, S.; Sauck, W. A.

    2003-12-01

    The alteration of physical properties by microbial activity in petroleum contaminated sediments was investigated using geophysical techniques in laboratory column experiments. Microbial population growth was determined by the Most Probable Number technique (MPN), community dynamics were determined by the rDNA intergenic spacer analysis (RISA), microbial mineralization of diesel fuel was assessed using dissolved inorganic carbon (DIC), enhanced mineral dissolution was determined by dissolved calcium, and the vertical geoelectrical profile was measured using DC resistivity (converted to conductivity). The columns simulated a saturation profile and contained sanitized, uniform sand with the following experimental treatments: diesel + microbes, diesel, microbes, and no treatment. After 16 months, two important conclusions were drawn. First, the relative increase in magnitude of the parameters measured was highest in the diesel + microbe column (showing at least 110% increase), lower in the diesel column and lowest (actually showing a decrease) in the column with no treatment. Further, the diesel + microbe column showed the greatest increase in oil degrading microbial populations (135%) compared to the column with no treatment, which showed no changes. Secondly, the depth at which the conductivity reached the maximum occurred within and slightly above the diesel layer (which represents a depth that was originally water wet). It was further observed that the relative change in bulk conductivity below the saturated zone is of a lower magnitude than above (<10%). These results suggest the diesel layer, and the zone slightly above, were the most biologically active. Additionally, the diesel + microbe column showed RISA fragments attributed to microbial succession typically observed in organic contaminant plumes. A simple Archie's Law analysis was used to estimate the pore water conductivities necessary to reproduce the bulk conductivity measured. This analysis shows that

  2. Passive sampling methods for contaminated sediments: Scientific rationale supporting use of freely dissolved concentrations

    PubMed Central

    Mayer, Philipp; Parkerton, Thomas F; Adams, Rachel G; Cargill, John G; Gan, Jay; Gouin, Todd; Gschwend, Philip M; Hawthorne, Steven B; Helm, Paul; Witt, Gesine; You, Jing; Escher, Beate I

    2014-01-01

    Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides a more relevant dose metric than total sediment concentration. Recent developments in PSMs have significantly improved our ability to reliably measure even very low levels of Cfree. Application of PSMs in sediments is preferably conducted in the equilibrium regime, where freely dissolved concentrations in the sediment are well-linked to the measured concentration in the sampler via analyte-specific partition ratios. The equilibrium condition can then be assured by measuring a time series or a single time point using passive samplers with different surface to volume ratios. Sampling in the kinetic regime is also possible and generally involves the application of performance reference compounds for the calibration. Based on previous research on hydrophobic organic contaminants, it is concluded that Cfree allows a direct assessment of 1) contaminant exchange and equilibrium status between sediment and overlying water, 2) benthic bioaccumulation, and 3) potential toxicity to benthic organisms. Thus, the use of PSMs to measure Cfree provides an improved basis for the mechanistic understanding of fate and transport processes in sediments and has the potential to significantly improve risk assessment and management of contaminated sediments. Integr Environ Assess Manag 2014;10:197–209. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:24288295

  3. A COMPENDIUM OF CHEMICAL, PHYSICAL AND BIOLOGICAL METHODS FOR ASSESSING AND MONITORING THE REMEDIATION OF CONTAMINATED SEDIMENT SITES

    EPA Science Inventory

    Considering the many organizations which have published methods for monitoring contaminated sediments and the large number of documents on this subject, it can be a formidable task for a superfund project manager to find methods appropriate for his or her contaminated sediment si...

  4. Green remediation and recycling of contaminated sediment by waste-incorporated stabilization/solidification.

    PubMed

    Wang, Lei; Tsang, Daniel C W; Poon, Chi-Sun

    2015-03-01

    Navigational/environmental dredging of contaminated sediment conventionally requires contained marine disposal and continuous monitoring. This study proposed a green remediation approach to treat and recycle the contaminated sediment by means of stabilization/solidification enhanced by the addition of selected solid wastes. With an increasing amount of contaminated sediment (20-70%), the 28-d compressive strength of sediment blocks decreased from greater than 10MPa to slightly above 1MPa. For augmenting the cement hydration, coal fly ash was more effective than lime and ground seashells, especially at low sediment content. The microscopic and spectroscopic analyses showed varying amounts of hydration products (primarily calcium hydroxide and calcium silicate hydrate) in the presence of coal fly ash, signifying the influence of pozzolanic reaction. To facilitate the waste utilization, cullet from beverage glass bottles and bottom ashes from coal combustion and waste incineration were found suitable to substitute coarse aggregate at 33% replacement ratio, beyond which the compressive strength decreased accordingly. The mercury intrusion porosimetry analysis indicated that the increase in the total pore area and average pore diameter were linearly correlated with the decrease of compressive strength due to waste replacement. All the sediment blocks complied with the acceptance criteria for reuse in terms of metal leachability. These results suggest that, with an appropriate mixture design, contaminated sediment and waste materials are useful resources for producing non-load-bearing masonry units or fill materials for construction uses. PMID:25522855

  5. PILOT IN SITU CAPPING PROJECT FOR PALOS VERDES SHELF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    The Palos Verdes Shelf Pilot Capping Project will evaluate the short-term results of capping the DDT- and PCB-contaminated sediment with clean sediment. It will also determine how these results are affected by variables such as cap material, placement method and water depth. The ...

  6. A TOXICITY ASSESSMENT APPROACH FOR THE EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Freshwater and marine sediment toxicity test were used to measure baseline toxicity of sediment samples collected from New York/New Jersey Harbor (NY/NJH) and East River (ER) (PAH contaminated) sediments and to determine the effectiveness of the developed biotreatment strategies ...

  7. HOW TO EVALUATE BENTHIC RECOVERY FROM REMEDIAL ACTIVITIES AT CONTAMINATED SEDIMENT SUPERFUND SITES

    EPA Science Inventory

    At contaminated sediment sites, the Superfund program usually must decide whether to leave the site alone, cap it, or dredge it. This decision is based in part upon the relative risk to the environment and human health posed by each alternative. Whatever decision is made at a s...

  8. Phytoremediation of polychlorinated biphenyl (PCB) contaminated sediments: A greenhouse feasibility study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contaminated sediments dredged from navigable waterways often are placed in confined disposal facilities to prevent further spread of the pollutants. Reducing contaminants to acceptable levels would allow for disposal of the sediments and further dredging activity. A greenhouse study was conducted t...

  9. DETERMINATION OF RATES AND EXTENT OF DECHLORINATION IN PCB-CONTAMINATED SEDIMENTS DURING MONITORED NATURAL RECOVERY

    EPA Science Inventory

    This "Sediment Issue" summarizes investigations carried out by the National Risk Management Research Laboratory (NRMRL) of U.S. EPA to evaluate the long-term recovery of polychlorinated biphenyl (PCB)-contaminated sediments via reductive dechlorination. The magnitude, extent, an...

  10. DIETARY ACCUMULATION OF PCBS FROM A CONTAMINATED SEDIMENT SOURCE BY A DEMERSAL FISH ('LEIOSTOMUS XANTHURUS')

    EPA Science Inventory

    Accumulation and dietary transfer of PCBs from contaminated harbor sediments were studied in a laboratory food chain. Results demonstrate that contaminated sediments serve as a source of PCBs for uptake and trophic transfer in marine systems. Fish exposed to PCB-contaminated sedi...

  11. A TOXICITY ASSESSMENT APPROACH TO EVALUATING IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Freshwater and marine sediment toxicity tests were used to measure baseline toxicity of sediment samples collected from New Jersey/New York Harbor (NJ/NY) (non-PAH- contaminated) sediment (ERC). Four freshwater toxicity tests were used: 1) amphipod (Hyalella azteca) mortality and...

  12. Assessing diversity and phytoremediation potential of mangroves for copper contaminated sediments in Subic Bay, Philippines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxic metal pollution of water and soil is a major environmental problem and most conventional remediation approaches may not provide adequate solutions. An alternative way of reducing copper (Cu) concentration from contaminated sediments is through phytoremediation. Presently, there are few researc...

  13. EVALUATION OF THE STATE-OF-THE-ART CONTAMINATED SEDIMENT TRANSPORT AND FATE MODELING SYSTEM

    EPA Science Inventory

    Modeling approaches for evaluating the transport and fate of sediment and associated contaminants are briefly reviewed. The main emphasis is on: 1) the application of EFDC (Environmental Fluid Dynamics Code), the state-of-the-art contaminated sediment transport and fate public do...

  14. Accelerating progress at contaminated sediment sites: moving from guidance to practice.

    PubMed

    Bridges, Todd S; Nadeau, Steven C; McCulloch, Megan C

    2012-04-01

    Contaminated sediments are a pervasive problem in the United States. Significant economic, ecological, and social issues are intertwined in addressing the nation's contaminated sediment problem. Managing contaminated sediments has become increasingly resource intensive, with some investigations costing tens of millions of dollars and the majority of remediation projects proceeding at a slow pace. At present, the approaches typically used to investigate, evaluate, and remediate contaminated sediment sites in the United States have largely fallen short of producing timely, risk-based, cost-effective, long-term solutions. With the purpose of identifying opportunities for accelerating progress at contaminated sediment sites, the US Army Corps of Engineers-Engineer Research and Development Center and the Sediment Management Work Group convened a workshop with experienced experts from government, industry, consulting, and academia. Workshop participants identified 5 actions that, if implemented, would accelerate the progress and increase the effectiveness of risk management at contaminated sediment sites. These actions included: 1) development of a detailed and explicit project vision and accompanying objectives, achievable short-term and long-term goals, and metrics of remedy success at the outset of a project, with refinement occurring as needed throughout the duration of the project; 2) strategic engagement of stakeholders in a more direct and meaningful process; 3) optimization of risk reduction, risk management processes, and remedy selection addressing 2 important elements: a) the deliberate use of early action remedies, where appropriate, to accelerate risk reduction; and b) the systematic and sequential development of a suite of actions applicable to the ultimate remedy, starting with monitored natural recovery and adding engineering actions as needed to satisfy the project's objectives; 4) an incentive process that encourages and rewards risk reduction; and 5

  15. Passive sampling methods for contaminated sediments: State of the science for organic contaminants

    PubMed Central

    Lydy, Michael J; Landrum, Peter F; Oen, Amy MP; Allinson, Mayumi; Smedes, Foppe; Harwood, Amanda D; Li, Huizhen; Maruya, Keith A; Liu, Jingfu

    2014-01-01

    This manuscript surveys the literature on passive sampler methods (PSMs) used in contaminated sediments to assess the chemical activity of organic contaminants. The chemical activity in turn dictates the reactivity and bioavailability of contaminants in sediment. Approaches to measure specific binding of compounds to sediment components, for example, amorphous carbon or specific types of reduced carbon, and the associated partition coefficients are difficult to determine, particularly for native sediment. Thus, the development of PSMs that represent the chemical activity of complex compound–sediment interactions, expressed as the freely dissolved contaminant concentration in porewater (Cfree), offer a better proxy for endpoints of concern, such as reactivity, bioaccumulation, and toxicity. Passive sampling methods have estimated Cfree using both kinetic and equilibrium operating modes and used various polymers as the sorbing phase, for example, polydimethylsiloxane, polyethylene, and polyoxymethylene in various configurations, such as sheets, coated fibers, or vials containing thin films. These PSMs have been applied in laboratory exposures and field deployments covering a variety of spatial and temporal scales. A wide range of calibration conditions exist in the literature to estimate Cfree, but consensus values have not been established. The most critical criteria are the partition coefficient between water and the polymer phase and the equilibrium status of the sampler. In addition, the PSM must not appreciably deplete Cfree in the porewater. Some of the future challenges include establishing a standard approach for PSM measurements, correcting for nonequilibrium conditions, establishing guidance for selection and implementation of PSMs, and translating and applying data collected by PSMs. Integr Environ Assess Manag 2014;10:167–178. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of

  16. Volume rendering for interactive 3D segmentation

    NASA Astrophysics Data System (ADS)

    Toennies, Klaus D.; Derz, Claus

    1997-05-01

    Combined emission/absorption and reflection/transmission volume rendering is able to display poorly segmented structures from 3D medical image sequences. Visual cues such as shading and color let the user distinguish structures in the 3D display that are incompletely extracted by threshold segmentation. In order to be truly helpful, analyzed information needs to be quantified and transferred back into the data. We extend our previously presented scheme for such display be establishing a communication between visual analysis and the display process. The main tool is a selective 3D picking device. For being useful on a rather rough segmentation, the device itself and the display offer facilities for object selection. Selective intersection planes let the user discard information prior to choosing a tissue of interest. Subsequently, a picking is carried out on the 2D display by casting a ray into the volume. The picking device is made pre-selective using already existing segmentation information. Thus, objects can be picked that are visible behind semi-transparent surfaces of other structures. Information generated by a later connected- component analysis can then be integrated into the data. Data examination is continued on an improved display letting the user actively participate in the analysis process. Results of this display-and-interaction scheme proved to be very effective. The viewer's ability to extract relevant information form a complex scene is combined with the computer's ability to quantify this information. The approach introduces 3D computer graphics methods into user- guided image analysis creating an analysis-synthesis cycle for interactive 3D segmentation.

  17. Ecotoxicity of uranium to Tubifex tubifex worms (Annelida, Clitellata, Tubificidae) exposed to contaminated sediment.

    PubMed

    Lagauzère, Sandra; Terrail, Raphaële; Bonzom, Jean-Marc

    2009-02-01

    In freshwater ecosystems, sediments act as an accumulation compartment for metallic pollutants as uranium. However, they are also the habitats of numerous benthic macroinvertebrates that directly influence the structure and functioning of such environments. Consequently, these organisms could be affected by uranium. This laboratory study aimed to assess the ecotoxicity of uranium on Tubifex tubifex through 12-day exposure to contaminated sediment (0-5980 microg U g(-1) dry wt). At high concentrations (>599 microg U g(-1) dry wt), malformations were observed, and survival, biomass and burrowing activity were all reduced. This relative high resistance in polluted environments can be explained mainly by the implementation of several processes as autotomy, regeneration ability, increased production of mucus, a hormetic effect on biomass and a probable strategy for avoiding the contaminated sediment. This study represents the first assessment of uranium impact on T. tubifex at realistic concentrations in sediments near mining sites. PMID:18555526

  18. Contaminated sediments database for Long Island Sound and the New York Bight

    USGS Publications Warehouse

    Mecray, Ellen L.; Reid, Jamey M.; Hastings, Mary E.; Buchholtz ten Brink, Marilyn R.

    2003-01-01

    The Contaminated Sediments Database for Long Island Sound and the New York Bight provides a compilation of published and unpublished sediment texture and contaminant data. This report provides maps of several of the contaminants in the database as well as references and a section on using the data to assess the environmental status of these coastal areas. The database contains information collected between 1956-1997; providing an historical foundation for future contaminant studies in the region.

  19. Passive sampling in contaminated sediment assessment: building consensus to improve decision making.

    PubMed

    Parkerton, Thomas F; Maruya, Keith A

    2014-04-01

    Contaminated sediments pose an ongoing, pervasive, global challenge to environmental managers, because sediments can reflect a legacy of pollution that can impair the beneficial uses of water bodies. A formidable challenge in assessing the risks of contaminated sediments has been the elucidation and measurement of contaminant bioavailability, expressed as the freely dissolved concentration (Cfree ) in interstitial water, which serves as a surrogate measure of the substances' chemical activity. Recent advances in passive sampling methods (PSMs) enable Cfree of sediment-associated contaminants to be quantified at trace levels, thereby overcoming current limitations of predictive models. As a result, PSMs afford the opportunity for a paradigm shift from traditional practice that can effectively reduce uncertainty in risk assessment and bolster confidence in the science used to support management of contaminated sediments. This paper provides a brief overview of the 5 subsequent papers in this series that review literature on PSM use in sediments for both organic and metal(loid) contaminants, outline the technical rationale for using PSMs as a preferred basis for risk assessment over conventional chemical analyses, describe practical considerations for and uncertainties associated with laboratory and field deployment of PSMs, discuss management application of PSMs, including illustrative case studies in which PSMs have been used in decision making, and highlight future research and communication needs. PMID:24142815

  20. Coupled effects of hydrodynamics and biogeochemistry on Zn mobility and speciation in highly contaminated sediments.

    PubMed

    Xie, Minwei; Jarrett, Brooke A; Da Silva-Cadoux, Cécile; Fetters, Kyle J; Burton, G Allen; Gaillard, Jean-François; Packman, Aaron I

    2015-05-01

    Porewater transport and diagenetic reactions strongly regulate the mobility of metals in sediments. We executed a series of laboratory experiments in Gust chamber mesocosms to study the effects of hydrodynamics and biogeochemical transformations on the mobility and speciation of Zn in contaminated sediments from Lake DePue, IL. X-ray absorption spectroscopy (XAS) indicated that the oxidation of surficial sediments promoted the formation of more mobile Zn species. Bulk chemical measurements of porewater, overlying water, and sediment also suggested that this process liberated aqueous metals to porewater and facilitated Zn efflux to the overlying water. In addition, sediment resuspension events increased the release of aqueous metals to both surficial porewater and the overlying water column. XAS analysis indicated that resuspension increased dissolution of Zn-sequestering mineral phases. These results show that both steady slow porewater transport and rapid episodic resuspension are important to the release of metal from fine-grained, low-permeability contaminated sediments. Thus, information on metals speciation and mobility under time-varying overlying flow conditions is essential to understanding the long-term behavior of metals in contaminated sediments. PMID:25875468

  1. Characterizing toxicity of metal-contaminated sediments from mining areas

    USGS Publications Warehouse

    Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.

    2015-01-01

    of acid-volatile sulfide (AVS), termed simultaneously-extracted metals (SEM), are widely used to estimate the ‘potentially-bioavailable’ fraction of metals that is not bound to sulfides (i.e., SEM-AVS). Metal concentrations in pore water are widely considered to be direct measures of metal bioavailability, and predictions of toxicity based on pore-water metal concentrations may be further improved by modeling interactions of metals with other pore-water constituents using Biotic Ligand Models. Data from sediment toxicity tests and metal analyses has provided the basis for development of sediment quality guidelines, which estimate thresholds for toxicity of metals in sediments. Empirical guidelines such as Probable Effects Concentrations or (PECs) are based on associations between sediment metal concentrations and occurrence of toxic effects in large datasets. PECs do not model bioavailable metals, but they can be used to estimate the toxicity of metal mixtures using by calculation of probable effect quotients (PEQ = sediment metal concentration/PEC). In contrast, mechanistic guidelines, such as Equilibrium Partitioning Sediment Benchmarks (ESBs) attempt to predict both bioavailability and mixture toxicity. Application of these simple bioavailability models requires more extensive chemical characterization of sediments or pore water, compared to empirical guidelines, but may provide more reliable estimates of metal toxicity across a wide range of sediment types.

  2. Phosphorus amendment reduces hematological effects of lead in mallards ingesting contaminated sediments

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Audet, D.J.

    2006-01-01

    Lead poisoning of waterfowl has been reported for decades in the Coeur d?Alene River Basin (CDARB) in Idaho as a result of the ingestion of lead-contaminated sediments. This study was conducted to determine whether the addition of phosphoric acid to sediments would reduce the bioavailability and toxicity of lead to mallards (Anas platyrhynchos) as related to adverse hematological effects and altered plasma chemistries. Mallards received diets containing 12% clean sediment (controls) or 12% sediment from three different CDARB sites containing 4520, 5390, or 6990 :g/g lead (dw) with or without phosphoric acid amendment. Blood lead concentrations were significantly higher in all CDARB treatment groups and ranged from geometric mean values of 5.0 ug/g for the first two sites to 6.2 ug/g for the third site. With amendments, all blood lead concentrations became 41% to 64% lower. Red blood cell ALAD activity was depressed by 90% or more with lead-contaminated sediment from all sites and did not differ with amended diets. Free erythrocyte protoporphyrin (FEP) concentrations were elevated by contaminated sediment from all sites. Amendment decreased the elevations in FEP by as much as 80%. Hematocrit values and hemoglobin concentrations were lower for all lead site sediments by as much as 30% for site 3. Plasma enzyme activities for ALT, CK, and LDH-L were elevated by as much as 2.2-fold, and plasma creatinine concentration was 1.7-fold higher for site 3 sediment. Amendments restored hematocrit, hemoglobin, and plasma enzyme activities so that they did not differ from controls. Although amendments of phosphorus substantially reduced the bioavailability of lead and alleviated many of the adverse hematological effects, lead concentrations in the blood of mallards fed the amended sediments were still above those believed to be harmful to waterfowl under the present conditions.

  3. Evaluation of factors affecting stakeholder risk perception of contaminated sediment disposal in Oslo harbor.

    PubMed

    Sparrevik, Magnus; Ellen, Gerald Jan; Duijn, Mike

    2011-01-01

    The management of environmental pollution has changed considerably since the growth of environmental awareness in the late 1960s. The general increased environmental concern and involvement of stakeholders in today's environmental issues may enhance the need to consider risk in a much broader social context rather than just as an estimate of ecological hazard. Risk perception and the constructs and images of risks held by stakeholders and society are important items to address in the management of environmental projects, including the management of contaminated sediments. Here we present a retrospective case study that evaluates factors affecting stakeholder risk perception of contaminated sediment disposal that occurred during a remediation project in Oslo harbor, Norway. The choice to dispose dredged contaminated sediments in a confined aquatic disposal (CAD) site rather than at a land disposal site has received a lot of societal attention, attracted large media coverage, and caused many public discussions. A mixed method approach is used to investigate how risk perceptive affective factors (PAF), socio-demographic aspects, and participatory aspects have influenced the various stakeholders' preferences for the two different disposal options. Risk perceptive factors such as transparency in the decision making process and controllability of the disposal options have been identified as important for risk perception. The results of the study also support the view that there is no sharp distinction in risk perception between experts and other parties and emphasizes the importance of addressing risk perceptive affective factors in similar environmental decision-making processes. Indeed, PAFs such as transparency, openness, and information are fundamental to address in sensitive environmental decisions, such as sediment disposal alternatives, in order to progress to more technical questions such as the controllability and safety. PMID:20809566

  4. Predicting the accumulation of mercury-contaminated sediment on riverbanks—An analytical approach

    NASA Astrophysics Data System (ADS)

    Pizzuto, Jim

    2012-07-01

    Mercury was introduced into the South River, Virginia, as a result of industrial use from 1929 to 1950. To guide remediation, an analytical model is developed to predict the mercury inventory resulting from deposition of mercury-contaminated sediment on subhorizontal surfaces adjacent to the river channel from 1930 to 2007. Sediment cores and geomorphic data were obtained from 27 sites. Mercury inventories range from 0.00019 to 0.573 kg m-2. High mercury inventories are associated with frequent inundation by floodwaters, forested riparian vegetation, and (at only four sites) unusually high sediment accumulation. Over the 10 km study reach, mercury inventories do not vary with downstream distance. The frequency of inundation at each coring site is determined from hydrologic data and a streamtube stage-discharge model. Water levels are exponentially distributed. A simple parameterization represents the enhanced ability of forested vegetation to trap mercury-contaminated sediments compared to nonforest vegetation. The calibrated model explains 62% of the observed variation in mercury inventories; 15 of the 27 predicted values are within a factor of 1.8 of the observed values. Calibration indicates a mercury deposition rate during inundation of 0.040 kg m-2 yr-1 (95% C.I. 0.032-0.048), that forested areas accumulate mercury-contaminated sediment 3.05 (95% C.I. 2.43-3.67) times faster than nonforested areas, and that floodwaters deeper than 0.98 (95% C.I. 0.45-1.53) m do not accumulate suspended sediment or mercury. At four sites, floodplain accumulation of 0.8-1.2 m occurred over a period of 39 (95% C.I. 22-56) years, while sedimentation is negligible (mean: 0.1 m, median: 0.03 m) at other sites.

  5. Use of life cycle assessments to evaluate the environmental footprint of contaminated sediment remediation.

    PubMed

    Sparrevik, Magnus; Saloranta, Tuomo; Cornelissen, Gerard; Eek, Espen; Fet, Annik Magerholm; Breedveld, Gijs D; Linkov, Igor

    2011-05-15

    Ecological and human risks often drive the selection of remedial alternatives for contaminated sediments. Traditional human and ecological risk assessment (HERA) includes assessing risk for benthic organisms and aquatic fauna associated with exposure to contaminated sediments before and after remediation as well as risk for human exposure but does not consider the environmental footprint associated with implementing remedial alternatives. Assessment of environmental effects over the whole life cycle (i.e., Life Cycle Assessment, LCA) could complement HERA and help in selecting the most appropriate sediment management alternative. Even though LCA has been developed and applied in multiple environmental management cases, applications to contaminated sediments and marine ecosystems are in general less frequent. This paper implements LCA methodology for the case of the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F)-contaminated Grenland fjord in Norway. LCA was applied to investigate the environmental footprint of different active and passive thin-layer capping alternatives as compared to natural recovery. The results showed that capping was preferable to natural recovery when analysis is limited to effects related to the site contamination. Incorporation of impacts related to the use of resources and energy during the implementation of a thin layer cap increase the environmental footprint by over 1 order of magnitude, making capping inferior to the natural recovery alternative. Use of biomass-derived activated carbon, where carbon dioxide is sequestered during the production process, reduces the overall environmental impact to that of natural recovery. The results from this study show that LCA may be a valuable tool for assessing the environmental footprint of sediment remediation projects and for sustainable sediment management. PMID:21520943

  6. Resuspension of sediment, a new approach for remediation of contaminated sediment.

    PubMed

    Pourabadehei, Mehdi; Mulligan, Catherine N

    2016-06-01

    Natural events and anthropogenic activities are the reasons of undesirable resuspension of contaminated sediments in aquatic environment. Uncontrolled resuspension could remobilize weakly bound heavy metals into overlying water and pose a potential risk to aquatic ecosystem. Shallow harbours, with contaminated sediments are subjected to the risk of uncontrolled resuspension. Remediation of sediments in these areas cannot be performed by conventional in situ methods (e.g. capping with or without reactive amendment). Ex situ remediation also requires dredging of sediment, which could increase the risk of spreading contaminants. Alternatively, the resuspension technique was introduced to address these issues. The concept of the resuspension method is that finer sediments have a greater tendency to adsorb the contamination. Therefore, finer sediments, believed carry more concentration of contaminants, were targeted for removal from aquatic environment by a suspension mechanism in a confined water column. The objective of this study was to evaluate the feasibility of the resuspension technique as a new approach for remediation of contaminated sediment and a viable option to reduce the risk of remobilization of contaminants in harbours due to an undesirable resuspension event. Unlike the common in situ techniques, the resuspension method could successfully reduce the total concentration of contaminants in almost all samples below the probable effect level (PEL) with no significant change in the quality of overlying water. The results indicated that removal efficiency could be drastically enhanced for metals in sediment with a higher enrichment factor. Moreover, availability of metals (e.g. Cd and Pb) with a high concentration in labile fractions was higher in finer sediments with a high enrichment factor. Consequently, removal of contaminants from sediment through the resuspension method could reduce the risk of mobility and availability of metals under changing

  7. Multi-volume visualization for interactive therapy planning

    NASA Astrophysics Data System (ADS)

    Wu, Liangshou; Amin, Viren R.; Ryken, Timothy; Long, Tao; Hagge, Mathew J.; Bryden, Mark

    2007-03-01

    During the past decade, various volume visualization techniques have been developed for different purposes, and many of them, such as direct volume rendering, maximum intensity projection and non-photorealistic rendering, have been implemented on consumer graphics hardware for real time visualization. However, effective multi-volume visualization, a way to establish the visual connections between two or more types of data, has not been adequately addressed even though it has wide applications in medical imaging and numerical simulation based on 3D physical model. In this paper, we aim to develop an effective GPU-based system for multi-volume visualization which is able to reveal both the connections and distinctions among multiple volume data. To address the main challenge for multi-volume visualization on how to establish the visual correspondences while maintaining the distinctive information among multiple volumes, a multi-level distinction mechanism is developed including 2D transfer function, mixed rendering modes, and volume clipping. Taking advantage of the fast hardware-supported processing capabilities, the system is implemented based on the GPU programming. Several advanced volume rendering techniques based on segmented volume are also implemented. The resulting visualization is a highly interactive image fusion system with high quality image and three-level volume distinction. We demonstrate the effectiveness of our system with a case study in which the heat effect on brain tumor, represented as a temperature volume resulting from high intensity focused ultrasound beam exposure over time, is visualized in the context of a MRI head volume.

  8. Community-level field method for testing the toxicity of contaminated sediments in estuaries

    SciTech Connect

    Watzin, M.C.; Roscigno, P.F. . National Wetlands Research Center); Burke, W.D. )

    1994-07-01

    The objective of this study was to demonstrate a method for testing the toxicity of contaminated sediments under field conditions. An artificial sediment that matches field sediment in grain-size distribution and organic matter content was mixed from 11 components and used as the test substrate. Clean sediments and sediments spiked with zinc were exposed in the field on a holding rack anchored on the bottom of Mobile Bay, Alabama. The abundance and diversity of benthic invertebrate recruits were used as indicators of sediment quality. The number of recruits was significantly reduced by the presence of zinc in one-week exposures.

  9. Hydrocarbon depuration and abiotic changes in artificially oil contaminated sediment in the subtidal

    NASA Astrophysics Data System (ADS)

    Berge, John A.; Lichtenthaler, Rainer G.; Oreld, Frøydis

    1987-04-01

    North Sea crude oil was mixed with sediment in concentrations similar to those found in heavily polluted areas (10 000 and 18 000 ppm) and placed in experimental boxes in the subtidal. Experiments were performed in two Norwegian fjords, the eutrophicated Oslofjord (experimental period of 3 months) and the non-eutrophicated Raunefjord (13 months). Physical and chemical responses of the contaminated sediment were compared with similarly treated control sediment without oil. Depuration was investigated using gas and liquid chromatographic analyses for determination of total hydrocarbon content and selected single aromatic components. Biodegradation was followed using n-alkane/branched alkane ratios. No depuration or biodegradation of hydrocarbon, or pronounced changes in sediment nitrogen and carbon content were observed after exposure in the Oslofjord. In the Raunefjord the redox potential was reduced by 75-200 mV in the oil contaminated sediment after 9 and 13 months. In the control sediment nitrogen and carbon content were significantly reduced after 9 and 13 months but did not change in the oil contaminated sediment except at the sediment surface (0-1 cm). A significantly higher macrofaunal biomass was found in the control sediment after 9 and 13 months but not after 5 months. After 13 months of exposure in the Raunefjord 33% of the originally added oil remained in the sediment. The most soluble components such as naphthalene and methylnaphthalene were reduced by two orders of magnitude and less soluble components such as phenanthrene and methylphenanthrene by one order of magnitude. Reduction was most pronounced at the sediment surface. Biodegradation in the Raunefjord sediment was documented after an initial lag period of 4-9 months. It is suggested that lower bioturbation and resuspension rates are responsible for the reducing conditions and the conservation of carbon, nitrogen and particle size distribution in the oil contaminated sediment. Results found as a

  10. A Magnification Lens for Interactive Volume Visualization

    SciTech Connect

    LaMar, E; Hamann, B; Joy, K I

    2001-07-19

    Volume visualization of large data sets suffers from the same problem that many other visualization modalities suffer from: either one can visualize the entire data set and lose small details or visualize a small region and lose the context. In this paper, they present a magnification lens technique for volume visualization. While the notion of a magnification-lens is not new, and other techniques attempt to simulate the physical properties of a magnifying lens, their contribution is in developing a magnification lens that is fast, can be implemented using a fairly small software overhead, and has a natural, intuitive appearance. The issue with magnification lens is the border, or transition, region. The lens center and exterior have a constant zoom factor, and are simple to render. It is the border region that blends between the external and interior magnification, and has a non-constant magnification. They use the perspective-correct textures capability, available in most current graphics systems, to produce a lens with a tessellated border region that approximates linear compression with respect to the radius of the magnification lens. They discuss how a cubic border can mitigate the discontinuities resulting from the use of a linear function, without significant performance loss. They discuss various issues concerning development of a three-dimensional magnification lens.

  11. Elevated nitrate enriches microbial functional genes for potential bioremediation of complexly contaminated sediments

    PubMed Central

    Xu, Meiying; Zhang, Qin; Xia, Chunyu; Zhong, Yuming; Sun, Guoping; Guo, Jun; Yuan, Tong; Zhou, Jizhong; He, Zhili

    2014-01-01

    Nitrate is an important nutrient and electron acceptor for microorganisms, having a key role in nitrogen (N) cycling and electron transfer in anoxic sediments. High-nitrate inputs into sediments could have a significant effect on N cycling and its associated microbial processes. However, few studies have been focused on the effect of nitrate addition on the functional diversity, composition, structure and dynamics of sediment microbial communities in contaminated aquatic ecosystems with persistent organic pollutants (POPs). Here we analyzed sediment microbial communities from a field-scale in situ bioremediation site, a creek in Pearl River Delta containing a variety of contaminants including polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs), before and after nitrate injection using a comprehensive functional gene array (GeoChip 4.0). Our results showed that the sediment microbial community functional composition and structure were markedly altered, and that functional genes involved in N-, carbon (C)-, sulfur (S)-and phosphorus (P)- cycling processes were highly enriched after nitrate injection, especially those microorganisms with diverse metabolic capabilities, leading to potential in situ bioremediation of the contaminated sediment, such as PBDE and PAH reduction/degradation. This study provides new insights into our understanding of sediment microbial community responses to nitrate addition, suggesting that indigenous microorganisms could be successfully stimulated for in situ bioremediation of POPs in contaminated sediments with nitrate addition. PMID:24671084

  12. Effects of organic carbon supply rates on mobility of previously bioreduced uranium in a contaminated sediment

    SciTech Connect

    Wan, J.; Tokunaga, T.K.; Kim, Y.; Brodie, E.; Daly, R.; Hazen, T.C.; Firestone, M.K.

    2008-05-15

    Bioreduction-based strategies for remediating uranium (U)-contaminated sediments face the challenge of maintaining the reduced status of U for long times. Because groundwater influxes continuously bring in oxidizing terminal electron acceptors (O{sub 2}, NO{sub 3}{sup -}), it is necessary to continue supplying organic carbon (OC) to maintain the reducing environment after U bioreduction is achieved. We tested the influence of OC supply rates on mobility of previously microbial reduced uranium U(IV) in contaminated sediments. We found that high degrees of U mobilization occurred when OC supply rates were high, and when the sediment still contained abundant Fe(III). Although 900 days with low levels of OC supply minimized U mobilization, the sediment redox potential increased with time as did extractable U(VI) fractions. Molecular analyses of total microbial activity demonstrated a positive correlation with OC supply and analyses of Geobacteraceae activity (RT-qPCR of 16S rRNA) indicated continued activity even when the effluent Fe(II) became undetectable. These data support our earlier hypothesis on the mechanism responsible for re-oxidation of microbial reduced U(IV) under reducing conditions; that microbial respiration caused increased (bi)carbonate concentrations and formation of stable uranyl carbonate complexes, thereby shifted U(IV)/U(VI) equilibrium to more reducing potentials. The data also suggested that low OC concentrations could not sustain the reducing condition of the sediment for much longer time.

  13. Planning dredging services in contaminated sediments for balanced environmental and investment costs.

    PubMed

    Wasserman, Julio Cesar; Barros, Sérgio Ricardo; Lima, Gilson Brito Alves

    2013-05-30

    Dredging of contaminated sediments has shown to be a harmful activity for the environment, because a number of contaminants can be resuspended and become available to the organisms. Furthermore, dredged contaminated sediments may cause significant damages in the dumping site. In order to avoid the drawbacks of this activity, better techniques have to be developed and the present article presents a new procedure for the planning of dredging that reduces the environmental impacts by reducing the amount of dredged sediments and, at the same time, reduces costs. The new technique uses screening of contaminant concentrations in the sediments that are normally part of the environmental impact assessment for dredging activity. A detailed mapping of the contamination, layer by layer is carried out and the areas where the action levels are reached are outlined with polygons, establishing limits within which sediments have to be dredged with safe procedures. In the case presented, construction of a harbor in Sepetiba Bay, Rio de Janeiro, Brazil, the safe procedure is cutter/suction dredging and pumping into a sub-aquatic confined disposal facility (CDF). A detailed evaluation of costs showed that if the whole layers of sediment were to be dumped into the CDF, the cost of the activity would be at least 63.82% more expensive than the proposed procedure, constituting an attractive advantage. Furthermore, as the size of the CDF is significantly smaller, less dredging is necessary, causing smaller environmental impact. PMID:23524396

  14. Speciation of metals in contaminated sediments from Oskarshamn Harbor, Oskarshamn, Sweden.

    PubMed

    Fathollahzadeh, Homayoun; Kaczala, Fabio; Bhatnagar, Amit; Hogland, William

    2014-02-01

    Bottom sediments in coastal regions have been considered the ultimate sink for a number of contaminants, e.g., toxic metals. In this current study, speciation of metals in contaminated sediments of Oskarshamn harbor in the southeast of Sweden was performed in order to evaluate metal contents and their potential mobility and bioavailability. Sediment speciation was carried out by the sequential extraction BCR procedure for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and the exchangeable (F1), reducible (F2), oxidizable (F3), and residual (R) fractionswere determined. The results have shown that Zn and Cd were highly associated with the exchangeable fraction (F1) with 42–58 % and 43–46 %, respectively, of their total concentrations in the mobile phase. The assessment of sediment contamination on the basis of quality guidelines established by the Swedish Environmental Protection Agency (SEPA) and the Italian Ministry of Environment (Venice protocol for dredged sediments) has shown that sediments from Oskarshamn harbor are highly contaminated with toxic metals, especially Cu, Cd, Pb, Hg, As, and Zn posing potential ecological risks. Therefore, it is of crucial importance the implementation of adequate strategies to tackle contaminated sediments in coastal regions all over the world. PMID:24078237

  15. Use of stochastic multi-criteria decision analysis to support sustainable management of contaminated sediments.

    PubMed

    Sparrevik, Magnus; Barton, David N; Bates, Mathew E; Linkov, Igor

    2012-02-01

    Sustainable management of contaminated sediments requires careful prioritization of available resources and focuses on efforts to optimize decisions that consider environmental, economic, and societal aspects simultaneously. This may be achieved by combining different analytical approaches such as risk analysis (RA), life cycle analysis (LCA), multicriteria decision analysis (MCDA), and economic valuation methods. We propose the use of stochastic MCDA based on outranking algorithms to implement integrative sustainability strategies for sediment management. In this paper we use the method to select the best sediment management alternatives for the dibenzo-p-dioxin and -furan (PCDD/F) contaminated Grenland fjord in Norway. In the analysis, the benefits of health risk reductions and socio-economic benefits from removing seafood health advisories are evaluated against the detriments of remedial costs and life cycle environmental impacts. A value-plural based weighing of criteria is compared to criteria weights mimicking traditional cost-effectiveness (CEA) and cost-benefit (CBA) analyses. Capping highly contaminated areas in the inner or outer fjord is identified as the most preferable remediation alternative under all criteria schemes and the results are confirmed by a probabilistic sensitivity analysis. The proposed methodology can serve as a flexible framework for future decision support and can be a step toward more sustainable decision making for contaminated sediment management. It may be applicable to the broader field of ecosystem restoration for trade-off analysis between ecosystem services and restoration costs. PMID:22191941

  16. Impact of contaminated-sediment resuspension on phytoplankton in the Biguglia lagoon (Corsica, Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Lafabrie, Céline; Garrido, Marie; Leboulanger, Christophe; Cecchi, Philippe; Grégori, Gérald; Pasqualini, Vanina; Pringault, Olivier

    2013-09-01

    In shallow human-impacted systems, sediment resuspension events can result in pulsed exposures of pelagic organisms to multiple contaminants. Here, we examined the impact of the resuspension of contaminated sediment on phytoplankton in the Biguglia lagoon (Corsica, Mediterranean Sea), by conducting an in situ microcosm experiment over a 96-h period. Natural phytoplankton was exposed to elutriates prepared from a contaminated-sediment resuspension simulating process, and its functional and structural responses were compared with those of non-exposed phytoplankton. The elutriates displayed moderate multiple contamination by trace metals and PAHs. Our results show that elutriate exposure induced both functional and structural phytoplankton changes. Elutriates strongly stimulated phytoplankton growth after 24 h of exposure. They also enhanced phytoplankton photosynthetic performance during the first hours of exposure (up to 48 h), before reducing it toward the end of the experiment. Elutriates were also found to slightly stimulate Bacillariophyceae and conversely to slightly inhibit Dinophyceae in the short term. Additionally, they were found to stimulate phycocyanin-rich picocyanobacteria in the short term (8-48 h) before inhibiting it in the longer term (72-96 h), and to inhibit eukaryotic nanophytoplankton in the short term (8-48 h) before stimulating it in the longer term (72-96 h). Sediment resuspensions are thus likely to have significant effects on the global dynamics and functions of phytoplankton in contaminated coastal environments.

  17. Interactive Volume Rendering of Diffusion Tensor Data

    SciTech Connect

    Hlawitschka, Mario; Weber, Gunther; Anwander, Alfred; Carmichael, Owen; Hamann, Bernd; Scheuermann, Gerik

    2007-03-30

    As 3D volumetric images of the human body become an increasingly crucial source of information for the diagnosis and treatment of a broad variety of medical conditions, advanced techniques that allow clinicians to efficiently and clearly visualize volumetric images become increasingly important. Interaction has proven to be a key concept in analysis of medical images because static images of 3D data are prone to artifacts and misunderstanding of depth. Furthermore, fading out clinically irrelevant aspects of the image while preserving contextual anatomical landmarks helps medical doctors to focus on important parts of the images without becoming disoriented. Our goal was to develop a tool that unifies interactive manipulation and context preserving visualization of medical images with a special focus on diffusion tensor imaging (DTI) data. At each image voxel, DTI provides a 3 x 3 tensor whose entries represent the 3D statistical properties of water diffusion locally. Water motion that is preferential to specific spatial directions suggests structural organization of the underlying biological tissue; in particular, in the human brain, the naturally occuring diffusion of water in the axon portion of neurons is predominantly anisotropic along the longitudinal direction of the elongated, fiber-like axons [MMM+02]. This property has made DTI an emerging source of information about the structural integrity of axons and axonal connectivity between brain regions, both of which are thought to be disrupted in a broad range of medical disorders including multiple sclerosis, cerebrovascular disease, and autism [Mos02, FCI+01, JLH+99, BGKM+04, BJB+03].

  18. International Conference on Contaminated Sediments - ContaSed 2015 8-13 March 2015, Monte Verità, Ascona, Switzerland.

    PubMed

    Chiaia-Hernandez, Aurea C; Giger, Walter

    2015-01-01

    About 80 participants from 22 countries from industry and academia gathered at the International Conference on Contaminated Sediments (ContaSed 2015) held at the Congressi Stefano Franscini (CSF), the conference center of ETH Zurich, located at Monte Verità, Ascona, Switzerland. ContaSed 2015 provided a platform for top experts as well as for junior researchers from different scientific disciplines to present recent results and novel approaches on the analysis, assessment and remediation of contaminated sediments. ContaSed 2015 served as a unique communication and discussion opportunity for environmental scientists with an emphasis on chemistry, sedimentology, ecotoxicology or remediation engineering. PMID:26507601

  19. Accumulation of copper, zinc, cadmium and lead from two contaminated sediments by three marine invertebrates: a laboratory study

    SciTech Connect

    Ray, S.; McLeese, D.W.; Peterson, M.R.

    1981-03-01

    Animals from areas with contaminated sediments have been shown in some cases to contain high levels of trace metals. In other cases, the tissue levels of contaminants were relatively constant regardless of the metal contents of the sediments. The availability of sediment-bound metals to bottom-dwelling organisms has been the subject of a few studies. This study describes the uptake of copper, zinc, cadmium and lead from natural, highly contaminated sediments by three marine invertebrates: Nereis virens, Macoma balthica and Crangon septemspinosa.

  20. Estimation of hydrocarbon biodegradation rates in gasoline-contaminated sediment from measured respiration rates

    USGS Publications Warehouse

    Baker, R.J.; Baehr, A.L.; Lahvis, M.A.

    2000-01-01

    An open microcosm method for quantifying microbial respiration and estimating biodegradation rates of hydrocarbons in gasoline-contaminated sediment samples has been developed and validated. Stainless-steel bioreactors are filled with soil or sediment samples, and the vapor-phase composition (concentrations of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), and selected hydrocarbons) is monitored over time. Replacement gas is added as the vapor sample is taken, and selection of the replacement gas composition facilitates real-time decision-making regarding environmental conditions within the bioreactor. This capability allows for maintenance of field conditions over time, which is not possible in closed microcosms. Reaction rates of CO2 and O2 are calculated from the vapor-phase composition time series. Rates of hydrocarbon biodegradation are either measured directly from the hydrocarbon mass balance, or estimated from CO2 and O2 reaction rates and assumed reaction stoichiometries. Open microcosm experiments using sediments spiked with toluene and p-xylene were conducted to validate the stoichiometric assumptions. Respiration rates calculated from O2 consumption and from CO2 production provide estimates of toluene and p- xylene degradation rates within about ??50% of measured values when complete mineralization stoichiometry is assumed. Measured values ranged from 851.1 to 965.1 g m-3 year-1 for toluene, and 407.2-942.3 g m-3 year-1 for p- xylene. Contaminated sediment samples from a gasoline-spill site were used in a second set of microcosm experiments. Here, reaction rates of O2 and CO2 were measured and used to estimate hydrocarbon respiration rates. Total hydrocarbon reaction rates ranged from 49.0 g m-3 year-1 in uncontaminated (background) to 1040.4 g m-3 year-1 for highly contaminated sediment, based on CO2 production data. These rate estimates were similar to those obtained independently from in situ CO2 vertical gradient and flux determinations at the

  1. A catchment-integrated approach to determine the importance of secondary sources of contaminated sediment

    NASA Astrophysics Data System (ADS)

    Andres Lopez-Tarazon, Jose; Byrne, Patrick; Mullan, Donal; Smith, Hugh

    2015-04-01

    Water pollution has been identified as one of the most important environmental challenges of the early 21st Century. The Water Framework Directive (WFD) (2008/105/EC) explicitly recognises the risk to water resources posed by sediment-associated contaminants in European river basins. The potential impacts on water supply and the biodiversity of aquatic ecosystems from sediment and associated contaminants may be further exacerbated by climate change pressures on water resources, as highlighted in the 2009 EU White Paper "Adapting to climate change: Towards a European framework for action" (SEC(2009) 386, 387, 388). Despite these concerns, the role of floodplains and other storage areas as secondary sources of contaminated sediment (i.e. metals) in river basins affected by historic industrial or mining pollution has been largely overlooked. Thereby, besides the sediment which is transported by the river, secondary sources of contaminants represent a credible threat to achieving EU water quality targets set by the WFD. This project addresses this issue by developing a catchment-based approach looking at metal geochemistry from source to sink (i.e., from sediment generation at slopes, passing through sediment transported by the river system, to sediment deposition at the storage areas to the outlet) and develop a geochemical model to predict the chemical aspects of metals transport and transformation. This approach will allow us to quantify (i) the sediment fluxes and associated contaminants flowing through the river, (ii) the storage areas contributions to downstream contaminated sediment fluxes, (ii) the timescales for the storage and removal of contaminated sediment in the sinks, and (iv) the transformation and bioavailability of the pollutants (i.e. metals) along the basin. Both physical and chemical aspects of metal transport will be considered by looking at metal geochemistry, mobility and bioavailability, hence producing information on chemical metal transport

  2. Digestive proteases of the lugworm (Arenicola marina) inhibited by Cu from contaminated sediments

    SciTech Connect

    Chen, Z.; Mayer, L.M.

    1998-03-01

    The authors examined potential toxic effects of copper released from contaminated sediments during deposit feeding of the lugworm, Arenicola marina. Titration of Cu solution into gut fluids can result in decreases in protease activity if sufficient Cu is added. The effects of Cu on gut proteases were confirmed by incubation of gut fluids with Cu-contaminated harbor sediments. Monitoring of Cu titration into gut fluids shows that enzyme inhibition and quenching of gut protein fluorescence occur only when sufficient Cu has been added to allow inorganic Cu species to become abundant. This threshold level probably represents the exhaustion of strong binding sites that act as protection against enzyme inhibition. Thus, sediments contaminated with Cu may have inhibitory effects on digestive processes in lugworms.

  3. Chemico/biological investigation of contaminated sediment from the Hamilton Harbour area of western Lake Ontario

    SciTech Connect

    Marvin, C.H.; Allan, L.; McCarry, B.E.; Bryant, D.W. )

    1993-01-01

    Highly contaminated sediment from the Hamilton Harbour area of western Lake Ontario was examined using a bioassay-directed fractionation methodology. A sediment sample was extracted using a Soxhlet apparatus and the resulting extract was fractionated into compound classes using an alumina clean-up step and high performance liquid chromatographic techniques. The resulting fractions were subjected to bioassays using TA98- and TA100-like strains modified by the inclusion of genes for the activating enzymes nitroreductase and O-acetyl-transferase. The majority of the mutagenic activity displayed by the sample extract was found to be present in the fraction containing the polycyclic aromatic hydrocarbons (PAH). Extracts of the PAH-containing fraction displayed dramatically higher responses with the TA100 type strains with metabolic activation. Further separation of the PAH-containing fraction showed the majority of the biological activity coeluted with PAH having molecular masses of 276, 278, and 302 amu.

  4. Phytoremediation of polychlorinated biphenyl (PCB)-contaminated sediment: a greenhouse feasibility study.

    PubMed

    Smith, K E; Schwab, A P; Banks, M K

    2007-01-01

    Contaminated sediments dredged from navigable waterways often are placed in confined disposal facilities to prevent further spread of the pollutants. Reducing contaminants to acceptable levels would allow for disposal of the sediments and further dredging activity. A greenhouse study was conducted to evaluate plant treatments and the addition of an organic amendment to decrease the concentration of PCB congeners found in Arochlor 1260. Sediment treated with the amendment and either low transpiring plants or no plants had the greatest removal of the PCB congeners. High-transpiring plants apparently prevented the highly reducing conditions required for reductive dechlorination of highly chlorinated PCBs. Most likely, the amendment provided labile carbon that initiated the reducing conditions needed for dechlorination. The sediment moisture content and moisture-related plant parameters were significant predictors of the PCB loss. Carex aquatalis and Spartina pectinata are predicted to be the most effective plant treatments for phytoremediation of PCBs. PMID:17215232

  5. ACTIVE CAPPING TECHNOLOGY - NEW APPROACHES FOR IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS

    SciTech Connect

    Knox, A.; Paller, M.; Roberts, J.

    2012-02-13

    This study evaluated pilot-scale active caps composed of apatite, organoclay, biopolymers, and sand for the remediation of metal-contaminated sediments. The active caps were constructed in Steel Creek, at the Savannah River Site near Aiken, South Carolina. Monitoring was conducted for 12 months. Effectiveness of the caps was based on an evaluation of contaminant bioavailability, resistance to erosion, and impacts on benthic organisms. Active caps lowered metal bioavailability in the sediment during the one-year test period. Biopolymers reduced sediment suspension during cap construction, increased the pool of carbon, and lowered the release of metals. This field validation showed that active caps can effectively treat contaminants by changing their speciation, and that caps can be constructed to include more than one type of amendment to achieve multiple goals.

  6. Effects of lead-contaminated sediment and nutrition on mallard duckling behavior and growth

    USGS Publications Warehouse

    Douglas-Stroebel, E.; Brewer, G.L.; Hoffman, D.J.

    2005-01-01

    Sediment ingestion has become a recognized exposure route for toxicants in waterfowl. The effects of lead-contaminated sediment from the Coeur d?Alene River Basin (CDARB) in Idaho were evaluated on mallard (Anas platyryhnchos) duckling behavior and growth over a five-week period using time-activity budgets. Day-old ducklings received either a clean sediment (24%) supplemented control diet, CDARB sediment (3,449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet). Ten different behaviors were monitored for time spent, including resting, standing, moving, drinking, dabbling, feeding, pecking, preening, bathing and swimming. Contaminated sediment (24% CDARB ) and lead acetate significantly decreased the proportion of time spent swimming. There were also problems with balance and mobility in the 24% CDARB and the lead acetate groups. With a less optimal diet (mixture of two thirds corn and one third standard diet) containing 24% clean sediment, nutrient level alone affected six different behaviors including feeding, pecking, swimming, preening, standing, and dabbling. Nutrient level also significantly decreased the growth rate and delayed the initial time of molt. When the corn diet contained CDARB sediment, the proportion of time spent bathing in the 24% CDARB group significantly decreased with marginal effects on resting and feeding. There were also instances of imbalance with 24% CDARB and corn diet, and duckling weights were significantly lower than in corn diet controls. The decreased time spent swimming or bathing, coupled with problems of balance and mobility, decreased growth, histopathological lesions and altered brain biochemistry (reported elsewhere) illustrate a potential threat to the survival of ducklings in the wild that are exposed to lead-containing sediments within the CDARB or elsewhere.

  7. Remediation of PCB-contaminated sediments, in Lake Jaernsjoen, River Emaan, Sweden -- Monitoring and results

    SciTech Connect

    Troedsson, B.; Helgee, A.

    1995-12-31

    Lake Jaernsjoen is a small lake in the Emaan river system which is considered to be one of the most valuable watercourses in Sweden. River Emaan is known for its high diversity of fish species, more than 25 species, e.g. wels (Siluris glanis). The river and its valley are of national interest from the viewpoints of both nature conservation and cultural history. Remediation implies certain hazards for the environment and substantial environmental monitoring is necessary for managing of the work in order to minimize damage to the environment. The content of PCB in the sediments of Jaernsjoen was estimated at about 400 kg and was the most important source for spreading of PCB in River Emaan. Remediation of the contaminated sediments took place during 1993 and 1994. It was carried out using a horizontal auger suction dredger. During dredging, the area with the most contaminated sediments was closed off by a silt curtain in order to protect River Emaan from release of suspended solids and PCB. The environmental monitoring during remediation included measuring of e.g. PCB, turbidity, suspended solids, TOC, nitrogen and phosphorus. Turbidity was measured automatically and registered continuously while samples for analysis of suspended solids and PCB were collected automatically and combined to form daily (suspended solids) and weekly (PCB) average samples. Turbidity, suspended solids and PCB were measured certify that the claims that were laid in the contract for the work and from authorities were fulfilled. Comparisons between monitoring stations upstream and downstream Lake Jaernsjoen show that the remediation have not influenced the River Emaan negatively.

  8. Using radiosilver and plutonium isotopes to trace the dispersion of contaminated sediment in Fukushima coastal catchments

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Ayrault, S.; Pointurier, F.; Onda, Y.; Laceby, J. P.; Lepage, H.; Chartin, C.; Cirella, M.; Pottin, A. C.; Hubert, A.; Lefèvre, I.

    2015-12-01

    The Fukushima Dai-ichi nuclear power plant (FDNPP) accident in March 2011 resulted in a 3000-km² radioactive pollution plume consisting predominantly of radiocesium (137Cs and 134Cs). This plume is drained by several rivers to the Pacific Ocean after flowing through less contaminated, but densely inhabited coastal plains. As the redistribution of radionuclide contaminated sediment could expose the local population to higher radiation rates, novel fingerprinting methods were developed to trace the downstream dispersion of contaminated sediment. First, the heterogeneous deposition of metastable silver-110 (110mAg) across these coastal catchments was used to investigate sediment migration. In particular, the 110mAg/137Cs activity ratio was measured in soils and river sediment demonstrating the occurrence of a seasonal cycle of soil erosion during typhoons and spring snowmelt in 2011 and 2012. However, due to the rapid decay of 110mAg (half-life of 250 days), alternative methods were required to continue tracking sediment from 2013 onwards. One promising method includes the analyses of plutonium isotopes to further understand sediment migration in the Fukushima region. For example, 241Pu/239Pu atom ratios measured in sediment collected in Fukushima coastal rivers shortly after the accident were shown to be significantly higher (0.0017 - 0.0884) than corresponding values attributed to the global fallout (0.00113 ± 0.00008). Additional analyses were conducted on sediment sampled in 2013 and 2014 after the start of decontamination works. These analyses show that the 241Pu/239Pu atom ratios decreased towards the global fallout values in rivers draining decontaminated paddy fields, demonstrating the effectiveness of remediation works.

  9. Physical verification of contaminated sediment remediation: Capping, confined aquatic disposal, and enhanced natural recovery

    SciTech Connect

    Browning, D.

    1995-12-31

    Dredging and disposal in a confined aquatic disposal (CAD) site, capping with clean sediment, and natural recovery are commonly used, cost-effective remedial practices for contaminated sediments. Recent projects in Puget Sound, Washington and Southern California involved dredging and use of the material for capping and CAD fill. Both of these projects required physical monitoring to document sediment placement. Dredged sediments placed at these sites were optically identified using sediment vertical profile system (SVPS) photography. Optical criteria to distinguish cap/construction materials include grain-size, reflectance, and texture. Environmental parameters such as the extent and thickness of the CAD material or sediment cap deposits are evaluated against design and performance goals, typically the isolation of contaminants from the biologically active portion of the sediment column. Using SVPS, coring and other technologies, the stratigraphic contact between the capping/CAD sediment and the native sediment can be discerned. These measurements observations can ground-truth and be coupled with remote sensing to provide a more complete characterization of the entire remedial area. Physical isolation of the benthic community can be discerned by examining SVPS images for depth of bioturbation and sediment stratigraphy. On the periphery of cap/CAD deposits, thin layers of clean sediment ranging upwards from 1 mm thick can be identified. Dependent on the pre-remediation benthic community at the site, these thin layers of CAP/CAD sediment can be bioturbated by resident benthic infauna immediately after placement. The deposition and subsequent assimilation of the clean cap material into the contaminated sediments effectively reduces the concentration of contaminants in the biologically active zone thereby enhancing natural recovery in areas where regulatory criteria are focused on the biologically active zone.

  10. Sequential Leaching of Chromium Contaminated Sediments - A Study Characterizing Natural Attenuation

    NASA Astrophysics Data System (ADS)

    Musa, D.; Ding, M.; Beroff, S.; Rearick, M.; Perkins, G.; WoldeGabriel, G. W.; Ware, D.; Harris, R.; Kluk, E.; Katzman, D.; Reimus, P. W.; Heikoop, J. M.

    2015-12-01

    Natural attenuation is an important process in slowing down the transport of hexavalent chromium, Cr(VI), an anthropogenic environmental contaminant, either by adsorption of Cr(VI) to sediments, or by reduction to nontoxic trivalent chromium, Cr(III). The capacity and mechanism of attenuation is explored in this sequential leaching study of different particle size fractions of chromium contaminated sediments and similar uncontaminated sediments from the regional aquifer near Los Alamos, New Mexico. Using this leaching protocol each sediment sample is split in two: one half is leached three times using a 0.1 M sodium bicarbonate/carbonate solution, while the second half is leached three times using a 0.01 M nitric acid, followed by two consecutively increasing magnitudes of nitric acid concentrations. Based on the amphoteric nature of chromium, alkaline leaching is used to establish the amount of Cr(VI) sorbed on the sediment, whereas acid leaching is used to establish the amount of Cr(III). The weak acid is predicted to release the attenuated anthropogenic Cr(III), without affecting Cr-bearing minerals. The sequential, stronger, acid is anticipated to leach Cr(III)-incorporated in the minerals. The efficiency and validation of the sequential leaching method is assessed by comparing the leaching behavior of bentonite and biotite samples, with and without loaded Cr(VI). A 97% chromium mass balance of leached Cr(VI)-loaded bentonite and biotite proves the viability of this method for further use on leaching contaminated sediments. By comparing contaminated and uncontaminated sediment leachate results, of chromium and other major and trace elements, the signature of anthropogenic chromium is determined. Further mineralogical characterization of the sediments provides a quantitative measure of the natural attenuation capacity for chromium. Understanding these results is pertinent in delineating the optimal procedure for the remediation of Cr(VI) in the regional aquifer

  11. Nitrogen fertilizer improves boron phytoextraction by Brassica juncea grown in contaminated sediments and alleviates plant stress.

    PubMed

    Giansoldati, Virginia; Tassi, Eliana; Morelli, Elisabetta; Gabellieri, Edi; Pedron, Francesca; Barbafieri, Meri

    2012-06-01

    In this study we evaluated the effect of different fertilizer treatments on Brassica plants grown on boron-contaminated sediments. Experiments were conducted in the laboratory and on the lysimeter scale. At laboratory scale (microcosm), five different fertilizers were tested for a 35-d period. On the lysimeter scale, nitrogen fertilization was tested at three different doses and plants were allowed to grow until the end of the vegetative phase (70 d). Results showed that nitrogen application had effectively increased plant biomass production, while B uptake was not affected. Total B phytoextracted increased three-fold when the highest nitrogen dose was applied. Phytotoxicity on Brassica was evaluated by biochemical parameters. In plants grown in unfertilized B-contaminated sediments, the activity of antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and pyrogallol peroxidase (PPX) increased, whereas catalase (CAT) decreased with respect to control plants. Addition of N progressively mitigated the alteration of enzymatic activity, thus suggesting that N can aid in alleviating B-induced oxidative stress. SOD activity was restored to control levels just at the lowest N treatment, whereas the CAT inhibition was partially restored only at the highest one. N application also lowered the B-induced increase in APX and PPX activities. Increased glutathione reductase activity indicated the need to restore the oxidative balance of glutathione. Data also suggest a role of glutathione and phytochelatins in B defense mechanisms. Results suggest that the nitrogen fertilizer was effective in improving B phytoextraction by increasing Brassica biomass and by alleviating B-induced oxidative stress. PMID:22382070

  12. IMP: Interactive mass properties program. Volume 1: Program description

    NASA Technical Reports Server (NTRS)

    Stewart, W. A.

    1976-01-01

    A method of computing a weights and center of gravity analysis of a flight vehicle using interactive graphical capabilities of the Adage 340 computer is described. The equations used to calculate area, volume, and mass properties are based on elemental surface characteristics. The input/output methods employ the graphic support of the Adage computer. Several interactive program options are available for analyzing the mass properties of a vehicle. These options are explained.

  13. Environmental Impact Of The Use Of Contaminated Sediments As Partial Replacement Of The Aggregate Used In Road Construction

    EPA Science Inventory

    The Indiana Harbor Canal (IHC) is a waterway extensively polluted with heavy metals and petroleum. Since there are limited disposal options for the petroleum-contaminated sediments (PCSs) of the canal, the environmental impact of IHC dewatered sediment when used as partial repla...

  14. Laboratory, Field, and Analytical Procedures for Using Passive Sampling in the Evaluation of Contaminated Sediments: User's Manual

    EPA Science Inventory

    Regardless of the remedial technology invoked to address contaminated sediments in the environment, there is a critical need to have tools for assessing the effectiveness of the remedy. In the past, these tools have included chemical and biomonitoring of the water column and sedi...

  15. Evaluation of a Sustainable Remediation Option: Beneficial Reuse of Petroleum-Contaminated Sediment as an Energy Source

    EPA Science Inventory

    The characteristics of petroleum-contaminated sediment (PCS) have been evaluated to assess whether the practice of its beneficial reuse as a sole or supplemental energy source is sustainable relative to other sediment remediation options such as monitored natural recovery (MNR), ...

  16. Flux Meter Assesses the Effects of Groundwater, Surface Water, and Contaminated Sediment Interactions on Ecosystems

    EPA Science Inventory

    The slow flow of water between groundwater (GW) and surface water (SW) is often referred to as seepage, or in scientific terms, advective flux. This slow flow at the GW/SW interface presents measurement difficulties. This project was conducted to develop a durable advective flux ...

  17. Metal-Macrofauna Interactions Determine Microbial Community Structure and Function in Copper Contaminated Sediments

    PubMed Central

    Mayor, Daniel J.; Gray, Nia B.; Elver-Evans, Joanna; Midwood, Andrew J.; Thornton, Barry

    2013-01-01

    Copper is essential for healthy cellular functioning, but this heavy metal quickly becomes toxic when supply exceeds demand. Marine sediments receive widespread and increasing levels of copper contamination from antifouling paints owing to the 2008 global ban of organotin-based products. The toxicity of copper will increase in the coming years as seawater pH decreases and temperature increases. We used a factorial mesocosm experiment to investigate how increasing sediment copper concentrations and the presence of a cosmopolitan bioturbating amphipod, Corophium volutator, affected a range of ecosystem functions in a soft sediment microbial community. The effects of copper on benthic nutrient release, bacterial biomass, microbial community structure and the isotopic composition of individual microbial membrane [phospholipid] fatty acids (PLFAs) all differed in the presence of C. volutator. Our data consistently demonstrate that copper contamination of global waterways will have pervasive effects on the metabolic functioning of benthic communities that cannot be predicted from copper concentrations alone; impacts will depend upon the resident macrofauna and their capacity for bioturbation. This finding poses a major challenge for those attempting to manage the impacts of copper contamination on ecosystem services, e.g. carbon and nutrient cycling, across different habitats. Our work also highlights the paucity of information on the processes that result in isotopic fractionation in natural marine microbial communities. We conclude that the assimilative capacity of benthic microbes will become progressively impaired as copper concentrations increase. These effects will, to an extent, be mitigated by the presence of bioturbating animals and possibly other processes that increase the influx of oxygenated seawater into the sediments. Our findings support the move towards an ecosystem approach for environmental management. PMID:23741430

  18. Influences of Organic Carbon Supply Rate on Uranium Bioreduction in Initially Oxidizing, Contaminated Sediment

    SciTech Connect

    Tokunaga, Tetsu K.; Wan, Jiamin; Kim, Yongman; Daly, Rebecca A.; Brodie, Eoin L.; Hazen, Terry C.; Herman, Don; Firestone, Mary K.

    2008-06-10

    Remediation of uranium (U) contaminated sediments through in-situ stimulation of bioreduction to insoluble UO{sub 2} is a potential treatment strategy under active investigation. Previously, we found that newly reduced U(IV) can be reoxidized under reducing conditions sustained by a continuous supply of organic carbon (OC) because of residual reactive Fe(III) and enhanced U(VI) solubility through complexation with carbonate generated through OC oxidation. That finding motivated this investigation directed at identifying a range of OC supply rates that is optimal for establishing U bioreduction and immobilization in initially oxidizing sediments. The effects of OC supply rate, from 0 to 580 mmol OC (kg sediment){sup -1} year{sup -1}, and OC form (lactate and acetate) on U bioreduction were tested in flow-through columns containing U-contaminated sediments. An intermediate supply rate on the order of 150 mmol OC (kg sediment){sup -1} year{sup -1} was determined to be most effective at immobilizing U. At lower OC supply rates, U bioreduction was not achieved, and U(VI) solubility was enhanced by complexation with carbonate (from OC oxidation). At the highest OC supply rate, resulting highly carbonate-enriched solutions also supported elevated levels of U(VI), even though strongly reducing conditions were established. Lactate and acetate were found to have very similar geochemical impacts on effluent U concentrations (and other measured chemical species), when compared at equivalent OC supply rates. While the catalysts of U(VI) reduction to U(IV) are presumably bacteria, the composition of the bacterial community, the Fe reducing community, and the sulfate reducing community had no direct relationship with effluent U concentrations. The OC supply rate has competing effects of driving reduction of U(VI) to low solubility U(IV) solids, as well as causing formation of highly soluble U(VI)-carbonato complexes. These offsetting influences will require careful control of OC

  19. Passive sampling methods for contaminated sediments: Practical guidance for selection, calibration, and implementation

    PubMed Central

    Ghosh, Upal; Driscoll, Susan Kane; Burgess, Robert M; Jonker, Michiel To; Reible, Danny; Gobas, Frank; Choi, Yongju; Apitz, Sabine E; Maruya, Keith A; Gala, William R; Mortimer, Munro; Beegan, Chris

    2014-01-01

    This article provides practical guidance on the use of passive sampling methods (PSMs) that target the freely dissolved concentration (Cfree) for improved exposure assessment of hydrophobic organic chemicals in sediments. Primary considerations for selecting a PSM for a specific application include clear delineation of measurement goals for Cfree, whether laboratory-based “ex situ” and/or field-based “in situ” application is desired, and ultimately which PSM is best-suited to fulfill the measurement objectives. Guidelines for proper calibration and validation of PSMs, including use of provisional values for polymer–water partition coefficients, determination of equilibrium status, and confirmation of nondepletive measurement conditions are defined. A hypothetical example is described to illustrate how the measurement of Cfree afforded by PSMs reduces uncertainty in assessing narcotic toxicity for sediments contaminated with polycyclic aromatic hydrocarbons. The article concludes with a discussion of future research that will improve the quality and robustness of Cfree measurements using PSMs, providing a sound scientific basis to support risk assessment and contaminated sediment management decisions. Integr Environ Assess Manag 2014;10:210–223. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. PMID:24288273

  20. TIE of a PAH-contaminated sediment using reproductive responses and EROD induction in rainbow trout

    SciTech Connect

    Brumley, C.M.; Kraak, G. van der; Munkittrick, K.R.

    1995-12-31

    PAH-contaminated sediments have been shown to cause a range of effects in fish. However, identifying the effective compounds can be time consuming and expensive. A toxicity identification evaluation (TIE) involves the analysis of mixtures by initially separating the mixture into toxic and non-toxic constituents. In this study, sediment was collected from Hamilton Harbor, Lake Ontario, and either extracted wet using methanol (MeOH) and dichloromethane (DCM), or freeze-dried and soxhlet extracted with MeOH and DCM. DCM extracts were solvent exchanged with dimethylsulfoxide (DMSO). Juvenile rainbow trout (Oncorhynchus mykiss) were exposed through the water to wet, freeze-dried, or extracted sediment, or to the MeOH or DMSO extracts for 4 days. Fish were analyzed for hepatic EROD activity, and plasma DMSO extracts, but was unaffected in fish exposed to extracted sediment. Estradiol levels were increased in fish exposed to the wet sediment, but not in fish exposed to the freeze-dried or extracted sediment, nor either of the solvent extracts. The response of testosterone to wet, freeze-dried and extracted sediment was inconsistent. Results indicate that both of the extraction methods efficiently removed from the sediment the compounds responsible for the effects on EROD activity and estradiol levels. However, neither method retained in the solvent extracts the compounds causing the increases in estradiol levels. Work continues to refine the freeze-drying and extraction methods; extracts will then be further fractionated using HPLC to identify the compounds of concern.

  1. Transport and deposition of plutonium-contaminated sediments by fluvial processes, Los Alamos Canyon, New Mexico

    SciTech Connect

    Graf, W.L.

    1996-10-01

    Between 1945 and 1952 the development of nuclear weapons at Los Alamos National Laboratory, New Mexico, resulted in the disposal of plutonium into the alluvium of nearby Acid and (to a lesser degree) DP Canyons. The purpose of this paper is to explore the connection between the disposal sites and the main river, a 20 km link formed by the fluvial system of Acid, Pueblo, DP, and Los Alamos Canyons. Empirical data from 15 yr of annual sediment sampling throughout the canyon system has produced 458 observations of plutonium concentration in fluvial sediments. These data show that, overall, mean plutonium concentrations in fluvial sediment decline from 10,000 fCi/g near the disposal area to 100 fCi/g at the confluence of the canyon system and the Rio Grande. Simulations using a computer model for water, sediment, and plutonium routing in the canyon system show that discharges as large as the 25 yr event would fail to develop enough transport capacity to completely remove the contaminated sediments from Pueblo Canyon. Lesser flows would move some materials to the Rio Grande by remobilization of stored sediments. The simulations also show that the deposits and their contaminants have a predictable geography because they occur where stream power is low, hydraulic resistance is high, and the geologic and/or geomorphic conditions provide enough space for storage. 38 refs., 13 figs., 1 tab.

  2. Evidencing the Impact of Coastal Contaminated Sediments on Mussels Through Pb Stable Isotopes Composition.

    PubMed

    Dang, Duc Huy; Schäfer, Jörg; Brach-Papa, Christophe; Lenoble, Véronique; Durrieu, Gaël; Dutruch, Lionel; Chiffoleau, Jean-Francois; Gonzalez, Jean-Louis; Blanc, Gérard; Mullot, Jean-Ulrich; Mounier, Stéphane; Garnier, Cédric

    2015-10-01

    Heavily contaminated sediments are a serious concern for ecosystem quality, especially in coastal areas, where vulnerability is high due to intense anthropogenic pressure. Surface sediments (54 stations), 50 cm interface cores (five specific stations), river particles, coal and bulk Pb plate from past French Navy activities, seawater and mussels were collected in Toulon Bay (NW Mediterranean Sea). Lead content and Pb stable isotope composition have evidenced the direct impact of sediment pollution stock on both the water column quality and the living organisms, through the specific Pb isotopic signature in these considered compartments. The history of pollution events including past and present contaminant dispersion in Toulon Bay were also demonstrated by historical records of Pb content and Pb isotope ratios in sediment profiles. The sediment resuspension events, as simulated by batch experiments, could be a major factor contributing to the high Pb mobility in the considered ecosystem. A survey of Pb concentrations in surface seawater at 40 stations has revealed poor seawater quality, affecting both the dissolved fraction and suspended particles and points to marina/harbors as additional diffuse sources of dissolved Pb. PMID:26348385

  3. The Microbial Community Structure in Petroleum-Contaminated Sediments Corresponds to Geophysical Signatures▿ †

    PubMed Central

    Allen, Jonathan P.; Atekwana, Estella A.; Atekwana, Eliot A.; Duris, Joseph W.; Werkema, D. Dale; Rossbach, Silvia

    2007-01-01

    The interdependence between geoelectrical signatures at underground petroleum plumes and the structures of subsurface microbial communities was investigated. For sediments contaminated with light non-aqueous-phase liquids, anomalous high conductivity values have been observed. Vertical changes in the geoelectrical properties of the sediments were concomitant with significant changes in the microbial community structures as determined by the construction and evaluation of 16S rRNA gene libraries. DNA sequencing of clones from four 16S rRNA gene libraries from different depths of a contaminated field site and two libraries from an uncontaminated background site revealed spatial heterogeneity in the microbial community structures. Correspondence analysis showed that the presence of distinct microbial populations, including the various hydrocarbon-degrading, syntrophic, sulfate-reducing, and dissimilatory-iron-reducing populations, was a contributing factor to the elevated geoelectrical measurements. Thus, through their growth and metabolic activities, microbial populations that have adapted to the use of petroleum as a carbon source can strongly influence their geophysical surroundings. Since changes in the geophysical properties of contaminated sediments parallel changes in the microbial community compositions, it is suggested that geoelectrical measurements can be a cost-efficient tool to guide microbiological sampling for microbial ecology studies during the monitoring of natural or engineered bioremediation processes. PMID:17351087

  4. Investigation of the release of PAHs from artificially contaminated sediments using cyclolipopeptidic biosurfactants.

    PubMed

    Portet-Koltalo, F; Ammami, M T; Benamar, A; Wang, H; Le Derf, F; Duclairoir-Poc, C

    2013-10-15

    Polycyclic aromatic hydrocarbons (PAHs) can be preponderant in contaminated sediments and understanding how they are sorbed in the different mineral and organic fractions of the sediment is critical for effective removal strategies. For this purpose, a mixture of seven PAHs was studied at the sediment/water interface and sorption isotherms were obtained. The influence of various factors on the sorption behavior of PAHs was evaluated, such as the nature of minerals, pH, ionic strength and amount of organic matter. Afterwards, the release of PAHs from the sediment by surfactants was investigated. The effectiveness of sodium dodecyl sulfate (SDS) was compared to natural biosurfactants, of cyclolipopeptidic type (amphisin and viscosin-like mixture), produced by two Pseudomonas fluorescens strains. The desorption of PAHs (from naphthalene to pyrene), from the highly retentive kaolinite fraction, could be favored by adding SDS or amphisin, but viscosin-like biosurfactants were only effective for 2-3 ring PAHs desorption (naphthalene to phenanthrene). Moreover, while SDS favors the release of all the target PAHs from a model sediment containing organic matter, the two biosurfactants tested were only effective to desorb the lowest molecular weight PAHs (naphthalene to fluorene). PMID:23995556

  5. Electrokinetic Treatment of Cr-, Cu-, and Zn-Contaminated Sediment: Cathode Modification

    PubMed Central

    Rajić, Ljiljana; Dalmacija, Božo; Perović, Svetlana Ugarčina; Krčmar, Dejan; Rončević, Srđan; Tomašević, Dragana

    2013-01-01

    Abstract Enhanced electrokinetic (EK) removal of Cr, Cu, and Zn from sediment by using original and modified integrated ion exchange (IIX™) cathodes was investigated. IIX cathode design and EK device process modifications were made to improve performance: separation of IIX cathode components (IIXS), combination of modified IIX cathode with pulsed electric field (IIXSP), and separation of IIX cathode components with addition of an anion exchange resin compartment (IIXA). After using the IIXSP, overall Cr, Cu, and Zn removal efficacies were significantly improved compared with the other treatments investigated. No improvements in overall Cr, Cu, and Zn removal efficacies were achieved by utilization of IIXA. Nevertheless, significant removal efficacies occurred at the anode region since distribution of the alkaline front was prevented. However, metal accumulation in the cathode region occurred. This was a consequence of metal cation complexation with Cl− released from the anion exchange resin that changed the direction of metal migration. Enhancing EK remediation of Cr-, Cu-, and Zn-contaminated sediment can be achieved by using a modified IIX cathode. PMID:24381480

  6. Electrokinetic Treatment of Cr-, Cu-, and Zn-Contaminated Sediment: Cathode Modification.

    PubMed

    Rajić, Ljiljana; Dalmacija, Božo; Perović, Svetlana Ugarčina; Krčmar, Dejan; Rončević, Srđan; Tomašević, Dragana

    2013-12-01

    Enhanced electrokinetic (EK) removal of Cr, Cu, and Zn from sediment by using original and modified integrated ion exchange (IIX™) cathodes was investigated. IIX cathode design and EK device process modifications were made to improve performance: separation of IIX cathode components (IIXS), combination of modified IIX cathode with pulsed electric field (IIXSP), and separation of IIX cathode components with addition of an anion exchange resin compartment (IIXA). After using the IIXSP, overall Cr, Cu, and Zn removal efficacies were significantly improved compared with the other treatments investigated. No improvements in overall Cr, Cu, and Zn removal efficacies were achieved by utilization of IIXA. Nevertheless, significant removal efficacies occurred at the anode region since distribution of the alkaline front was prevented. However, metal accumulation in the cathode region occurred. This was a consequence of metal cation complexation with Cl(-) released from the anion exchange resin that changed the direction of metal migration. Enhancing EK remediation of Cr-, Cu-, and Zn-contaminated sediment can be achieved by using a modified IIX cathode. PMID:24381480

  7. Chemical characterization and toxicological testing of windrow composts from explosives-contaminated sediments

    SciTech Connect

    Griest, W.H.; Tyndall, R.L.; Stewart, A.J.; Caton, J.E.; Vass, A.A.; Ho, C.H.; Caldwell, W.M. )

    1995-01-01

    Aerated and nonaerated windrow composts of explosives-contaminated sediments at the Umatilla Army Depot Activity (UMDA, Hermiston, OR) were characterized chemically and toxicologically as a function of composting time. The concentrations of explosives in organic solvent extracts of the composts and in the aqueous leachates of the composts, the bacterial mutagenicity of organic solvent extracts from the composts, and the toxicity of aqueous leachates from the composts to Ceriodaphnia dubia all declined rapidly with composting. The nonaerated windrow method of composting was slightly more efficient than was the aerated windrow method for reducing explosives concentrations in the composts and in their leachates. Extractable mutagenicity declined 99.7 and 97.9%, respectively, for strains TA-98 and TA-100 (without S-9 metabolic activation) in the nonaerated compost. The two types (aerated and nonaerated) of windrow composts had about the same level of efficiency in lowering leachable toxicity based on reductions in C. dubia survival and fecundity, respectively. Thus, windrow composting appeared to be at least as effective as static-pile and mechanically stirred composting evaluated previously. Windrow composting also appeared to be somewhat more effective for HMX transformation.

  8. Scale-dependency of macroinvertebrate communities: responses to contaminated sediments within run-of-river dams.

    PubMed

    Colas, Fanny; Archaimbault, Virginie; Devin, Simon

    2011-03-01

    Due to their nutrient recycling function and their importance in food-webs, macroinvertebrates are essential for the functioning of aquatic ecosystems. These organisms also constitute an important component of biodiversity. Sediment evaluation and monitoring is an essential aspect of ecosystem monitoring since sediments represent an important component of aquatic habitats and are also a potential source of contamination. In this study, we focused on macroinvertebrate communities within run-of-river dams, that are prime areas for sediment and pollutant accumulation. Little is known about littoral macroinvertebrate communities within run-of-river dam or their response to sediment levels and pollution. We therefore aimed to evaluate the following aspects: the functional and structural composition of macroinvertebrate communities in run-of-river dams; the impact of pollutant accumulation on such communities, and the most efficient scales and tools needed for the biomonitoring of contaminated sediments in such environments. Two run-of-river dams located in the French alpine area were selected and three spatial scales were examined: transversal (banks and channel), transversal x longitudinal (banks/channel x tail/middle/dam) and patch scale (erosion, sedimentation and vegetation habitats). At the patch scale, we noted that the heterogeneity of littoral habitats provided many available niches that allow for the development of diversified macroinvertebrate communities. This implies highly variable responses to contamination. Once combined on a global 'banks' spatial scale, littoral habitats can highlight the effects of toxic disturbances. PMID:21272919

  9. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M; Harsh, James B.

    2012-01-01

    Despite remediation efforts at the former nuclear weapons facility, leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford site 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a source for U supply to ground water. We investigated U release from Hanford capillary fringe sediments by packing sediments into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios. After specified times, samples were centrifuged. Within the first three days, there was an initial rapid release of 6-9% of total U, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemical modeling indicated that calcite could precipitate in the narrowest solution-to-solid ratio experiment. After the rapid initial release in the first three days for the wide solution-to-solid ratio experiments, there was sustained release of U into the pore water. This sustained release of U from the sediments had diffusion-limited kinetics.

  10. Desorption of organochlorine pesticides from historically contaminated sediments into water-biofuel mixtures

    NASA Astrophysics Data System (ADS)

    Otero-Diaz, M.; Demond, A. H.

    2014-12-01

    Gasoline spills in surface waters generally volatilize due to their low miscibility and high volatility. However, biofuel blends may contain ethanol, a compound completely miscible in water. As hazardous components of gasoline are more soluble in ethanol than in water, the presence of ethanol increases the solubilization of these components, such as benzene, toluene, ethylbenzene, and xylenes (BTEX), in surface water. Furthermore, many of these spills may occur in water bodies that have sediments that are historically contaminated with persistent organic contaminants such as organochlorine pesticides. High concentrations of ethanol in the water column, along with solubilized components of gasoline, may increase the desorption of organochlorine pesticides from the sediment. Thus spills of ethanol/gasoline fuel blends have the potential of increasing concentrations of hazardous compounds in rivers and lakes, resulting in increased risk for human and ecological exposure. Using UNIFAC to calculate activity coefficients, one can predict the enhancement of the solubility of pesticides in the aqueous phase as the ethanol fraction increases. Moreover, by predicting the solubility of pesticides in both the aqueous phase and an organic liquid phase, one can construct ternary phase diagrams that show the partitioning behavior of pesticides as a function of ethanol fraction. Such information is useful in estimating the amount of desorption from contaminated sediments that may occur in the presence of biofuel spills. In order to confirm the predicted values, experiments have been conducted to measure the impact of ethanol on the partitioning coefficients of pesticides.

  11. Associations between degraded benthic communities and contaminated sediments: Sabine Lake, Lake Pontchartrain, and Choctawhatchee Bay

    SciTech Connect

    Engle, V.D.; Summers, J.K.; Macauley, J.M.

    1994-12-31

    The Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) in the Gulf of Mexico supplements its base sampling effort each year with localized, intensive spatial sampling in selected large estuarine systems. By selecting random locations within 70 km{sup 2} hexagonal areas, individual estuaries were sampled using EMAP methods but at four times the density as base sampling. In 1992, 19 sites were sampled in Lake Pontchartrain, Louisiana. In 1 993, 18 sites were sampled in Sabine Lake, Texas and 12 sites were sampled in Choctawhatchee Bay, Florida. At all sites, sediment grabs were taken and analyzed for benthic species composition and abundance, for toxicity to Ampelisca, and for organic and inorganic sediment contaminants. An indicator of biotic integrity, the benthic index, was calculated to represent the status of benthic communities. A series of statistical techniques, such as stepwise regression analysis, were employed to determine whether the variation in the benthic index could be associated with variation in sediment contaminants, sediment toxicity, or levels of dissolved oxygen. Spatial distributions of these parameters were examined to determine the geographical co-occurrence of degraded benthic communities and environmental stressors. In Lake Pontchartrain, for example, 85% of the variation in the benthic index was associated with decreased levels of dissolved oxygen, and increased concentrations of PCBs, alkanes, copper, tin, and zinc in the sediments.

  12. Relative sensitivity of five benthic invertebrate species to reference toxicants and resin-acid contaminated sediments

    SciTech Connect

    Hickey, C.W.; Martin, M.L.

    1995-08-01

    Five sediment-dwelling native New Zealand freshwater invertebrate species (amphipod, Chaetocorophium c.f. lucasi; clam, Sphaerium novaezelandiae; oligochaete, Lumbriculus variegatus; tanaid, Tanais standfordi; and the burrowing mayfly, Ichthybotus hudsoni) were assessed for their suitability for sediment toxicity testing by comparison of sensitivity to reference toxicants [phenol and pentachlorophenol (PCP)] and contaminated sediments. The 96-h EC50 values at 20 C showed a greater range in test sensitivity for phenol (30-fold range) from the most sensitive test, amphipod (8.1 mg/L), to the least sensitive one, clam (243 mg/L), compared with PCP (14-fold range), with amphipod the most sensitive test species (0.13 mg/L) and tanaid the least sensitive (1.8 mg/L). Clam reburial was a more sensitive end point than was lethality for phenol (by 20-fold) and PCP (by 2.4-fold). Four of the test species, excluding the tanaid, showed good 10-d survival in reference muds ({ge}87%) but lower survival in sand sediments ({ge}79%). Bleached kraft mill sediment containing high resin-acid concentrations (total 1,900 mg/kg dry weight) showed significant reductions in amphipod survival (15%), clam reburial (30%), and oligochaete survival (17%), and reproduction (49%). Amphipods, clams, and oligochaetes were the most promising species for sublethal test development.

  13. Identification and confirmation of ammonia toxicity in contaminated sediments using a modified toxicity identification evaluation approach

    SciTech Connect

    Sprang, P.A. Van; Janssen, C.R.

    1997-12-01

    Toxicity identification of sediment pore waters from four sites in the Upper Scheldt (Belgium) was assessed using a simplified and discriminative toxicity identification evaluation procedure. The samples from all locations exhibited acute toxicity toward the freshwater crustacean Thamnocephalus platyurus. Toxicity was removed or considerably reduced by the cation exchange resins and air stripping at pH 11. In addition, the toxicity of the pore waters was found to be highly pH dependent. Increased toxicity was observed at higher pH levels, whereas reduced toxicity was found at lower pH levels. Based on these results, ammonia was suggested as the main toxic agent. The presence of ammonia concentrations exceeding the 24-h median lethal concentration and comparison of the toxicity characterization profiles of the pore waters with those of the suspected toxicant supported this hypothesis. Furthermore, a significant positive correlation between the observed toxicity of the pore waters and the expected toxicity (due to the presence of the suspected toxicant) confirmed ammonia as the true toxic agent. Finally, the ratio between the expected ammonia toxicity and the observed toxicity from the characterization tests was approx. 1, meaning that all or most of the observed toxicity was caused by the presence of one toxicant (i.e., ammonia). The developed toxicity identification evaluation procedure is suggested as a useful tool for the identification and confirmation of toxicants in contaminated sediments.

  14. Part I: Integrated water quality management: river basin approach. Geochemical techniques on contaminated sediments--river basin view.

    PubMed

    Förstner, Ulrich

    2003-01-01

    The big flood in the upper Elbe River catchment area has revealed a wide spectrum of problems with contaminated sediments. So far, an effective strategy for managing contaminated sediments on a river basin scale is still missing and it seems that not much has been learned from the lessons received during the last decade. In the following overview, special emphasis is given to the utilization of geochemically-based techniques for sediment remediation, which can be applied in different parts of a river basin. The examples presented here are mostly from the Elbe River catchment area. In general, new technical problem solutions need a set of practical process knowledge that uses a wide range of simulation techniques, as well as models in different spatial and temporal scales. The evaluation of recent flood events clearly demonstrates the importance of chemical expertise in the decision-making process for the sustainable development in river basins. PMID:12635960

  15. Utilization of recycled charcoal as a thermal source and adsorbent for the treatment of PCDD/Fs contaminated sediment.

    PubMed

    Zhao, Long; Hou, Hong; Iwasaki, Kanae; Terada, Akihiko; Hosomi, Masaaki

    2012-07-30

    A novel heat treatment process in which charcoal was used as both a thermal source and an adsorbent was investigated as a low-cost method for removal of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from solids. Three laboratory scale experiments involving various ratios of charcoal to contaminated sediment and air superficial velocities were performed. The results indicated that the total and toxic equivalency quantities (TEQ) concentrations of PCDD/Fs decreased significantly in the treated sediment of all runs with removal efficiencies greater than 96% and 90%, which resulted in residual concentrations below the Japanese standard limit of 0.15ng-TEQg(-1). The charcoal/contaminated sediment ratio and air superficial velocity were determinant factors controlling the PCDD/Fs concentrations and homologue profiles in effluent. As the air superficial velocity increased and charcoal/contaminated sediment ratio decreased, more PCDD/Fs were released from the sediment as fly ash, making them less likely to remain in the treated sediment. These phenomena were likely a result of the vapor pressure of PCDD/Fs, contact time with effluent gas and amount of PCDD/Fs adsorbed by charcoal. The developed process would promise an alternative to a conventional remediation process for PCDD/Fs contaminated solids. PMID:22633545

  16. Exposure Render: An Interactive Photo-Realistic Volume Rendering Framework

    PubMed Central

    Kroes, Thomas; Post, Frits H.; Botha, Charl P.

    2012-01-01

    The field of volume visualization has undergone rapid development during the past years, both due to advances in suitable computing hardware and due to the increasing availability of large volume datasets. Recent work has focused on increasing the visual realism in Direct Volume Rendering (DVR) by integrating a number of visually plausible but often effect-specific rendering techniques, for instance modeling of light occlusion and depth of field. Besides yielding more attractive renderings, especially the more realistic lighting has a positive effect on perceptual tasks. Although these new rendering techniques yield impressive results, they exhibit limitations in terms of their exibility and their performance. Monte Carlo ray tracing (MCRT), coupled with physically based light transport, is the de-facto standard for synthesizing highly realistic images in the graphics domain, although usually not from volumetric data. Due to the stochastic sampling of MCRT algorithms, numerous effects can be achieved in a relatively straight-forward fashion. For this reason, we have developed a practical framework that applies MCRT techniques also to direct volume rendering (DVR). With this work, we demonstrate that a host of realistic effects, including physically based lighting, can be simulated in a generic and flexible fashion, leading to interactive DVR with improved realism. In the hope that this improved approach to DVR will see more use in practice, we have made available our framework under a permissive open source license. PMID:22768292

  17. Interactive Isogeometric Volume Visualization with Pixel-Accurate Geometry.

    PubMed

    Fuchs, Franz G; Hjelmervik, Jon M

    2016-02-01

    A recent development, called isogeometric analysis, provides a unified approach for design, analysis and optimization of functional products in industry. Traditional volume rendering methods for inspecting the results from the numerical simulations cannot be applied directly to isogeometric models. We present a novel approach for interactive visualization of isogeometric analysis results, ensuring correct, i.e., pixel-accurate geometry of the volume including its bounding surfaces. The entire OpenGL pipeline is used in a multi-stage algorithm leveraging techniques from surface rendering, order-independent transparency, as well as theory and numerical methods for ordinary differential equations. We showcase the efficiency of our approach on different models relevant to industry, ranging from quality inspection of the parametrization of the geometry, to stress analysis in linear elasticity, to visualization of computational fluid dynamics results. PMID:26731454

  18. Using SPMDs To Assess Natural Recovery Of PCB-Contaminated Sediments In Lake Hartwell, SC: I. A Field Test Of New In-Situ Deployment Methods

    EPA Science Inventory

    Results from the field testing of some innovative sampling methods developed to evaluate risk management strategies for polychlorinated biphenyl (PCB) contaminated sediments are presented. Semipermeable membrane devices (SPMDs) were combined with novel deployment methods to quan...

  19. Mineral-Water Interface Processes Affecting Uranium Fate in Contaminated Sediments

    NASA Astrophysics Data System (ADS)

    Catalano, J. G.

    2011-12-01

    Widespread uranium contamination of soil, sediments, and groundwater systems has resulted from mining activities, nuclear weapon production, and energy generation. The fate and transport of uranium in such systems is strongly affected by geochemical processes occurring at mineral-water interfaces. I will present a summary of the mineral-water interface processes found to affect uranium fate in example contaminated sediments at the U.S. Department of Energy's Hanford sites and in related model systems. Processes occurring under oxic conditions will be the primary focus of this talk as under these conditions uranium is most mobile and thus presents the greatest hazard. Three dominant solid-phase uranium species are observed in contaminated soil and sediments at the Hanford site: uranyl silicates, uranyl phosphates, and uranyl adsorbed to clays and iron oxides. In deep sediments, uranyl silicates are found in microfractures in feldspar grains, likely because slow diffusion in such fractures maintains a high silicate activity. Such silicates are also found in waste-impacted shallow sediments and soil; waste fluids or evaporative processes may have generated the silicate activity needed to produce such phases. Uranyl phosphates are less abundant, occurring primarily in shallow sediments exposed to P-bearing waste fluids. However, remediation approaches under consideration may produce substantial quantities of uranyl phosphates in the future. Adsorbed uranyl is dispersed throughout contaminated soils and shallow sediments and likely has the greatest potential for remobilization. Analogue studies show that precipitation of uranyl phosphates is rapid when such phases are supersaturated and that both homogeneous and heterogeneous nucleation may occur. Specific adsorption of uranyl to minerals is strongly affected by the presence of complexation anions. Carbonate suppresses uranyl adsorption but also forms uranyl-carbonate ternary surface complexes. At conditions below

  20. Osmium isotopes demonstrate distal transport of contaminated sediments in Chesapeake Bay

    USGS Publications Warehouse

    Helz, G.R.; Adelson, J.M.; Miller, C.V.; Cornwell, J.C.; Hill, J.M.; Horan, M.; Walker, R.J.

    2000-01-01

    Because the isotopic composition of anthropogenic Os is normally distinctive in comparison to continental crust and is precisely measurable, this platinum-group element is attractive as a tracer of transport pathways for contaminated sediments in estuaries. Evidence herein and elsewhere suggest that biomedical research institutions are the chief source of anthropogenic Os. In the Chesapeake Bay region, uncontaminated sediments bear a crustal 187Os/188Os signature of 0.73 ?? 0.10. Slightly higher 187Os/188Os ratios occur in Re-rich Coastal Plain deposits due to post- Miocene 187Re decay. The upper Susquehanna Basin yields sediments also with higher 187Os/188Os. Beginning in the late 1970s, this signal was overprinted by a low 187Os/188Os (anthropogenic) source in the lower Susquehanna Basin. In the vicinity of Baltimore, which is a major center of heavy industry as well as biomedical research, anthropogenic Os has been found only in sediments impacted by the principal wastewater treatment plant. Surprisingly, a mid-Bay site distant from anthropogenic sources contains the strongest anthropogenic Os signal in the data set, having received anthropogenic Os sporadically since the mid-20th Century. Transport of particles to this site overrode the northward flowing bottom currents. Finding anthropogenic Os at this site cautions that other particle-borne substances, including hazardous ones, could be dispersed broadly in this estuary.Because the isotopic composition of anthropogenic Os is normally distinctive in comparison to continental crust and is precisely measurable, this platinum-group element is attractive as a tracer of transport pathways for contaminated sediments in estuaries. Evidence herein and elsewhere suggest that biomedical research institutions are the chief source of anthropogenic Os. In the Chesapeake Bay region, uncontaminated sediments bear a crustal 187Os/188Os signature of 0.73 ?? 0.10. Slightly higher 187Os/188Os ratios occur in Re-rich Coastal

  1. Emphatic, interactive volume rendering to support variance in user expertise.

    PubMed

    Stredney, Don; Ebert, David S; Svakhine, Nikolai; Bryan, Jason; Sessanna, Dennis; Wiet, Gregory J

    2005-01-01

    Various levels of representation, from abstract to schematic to realistic, have been exploited for millennia to facilitate the transfer of information from one individual to another. Learning complex information, such as that found in biomedicine, proves specifically problematic to many, and requires incremental, step-wise depictions of the information to clarify structural, functional, and procedural relationships.Emerging volume-rendering technique, such as non-photorealistic representation, coupled with advances in computational speeds, especially new graphical processing units, provide unique capabilities to explore the use of various levels of representation in interactive sessions. We have developed a system that produces images that simulate pictorial representations for both scientific and biomedical visualization. The system combines traditional and novel volume illustration techniques. We present examples from our efforts to distill representational techniques for both creative exploration and emphatic presentation for clarity. More specifically, we present our efforts to adapt these techniques for interactive simulation sessions being developed in a concurrent project for resident training in temporal bone dissection simulation. The goal of this effort is to evaluate the use of emphatic rendering to guide the user in an interactive session and to facilitate the learning of complex biomedical information, including structural, functional, and procedural information. PMID:15718791

  2. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Palumbo, Anthony Vito; Ravel, Bruce; Phelps, Tommy Joe; Schadt, Christopher Warren; Brandt, Craig C

    2009-01-01

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  3. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Madden, Andrew S.; Palumbo, Anthony V.; Ravel, Bruce; Vishnivetskaya, Tatiana A.; Phelps, Tommy J.; Schadt, Christopher W.; Brandt, Craig C.

    2009-03-16

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  4. Fish bioturbation of cadmium-contaminated sediments: Factors affecting Cd availability to Daphnia magna

    SciTech Connect

    Wall, S.B.; La Point, T.W.; Isely, J.J.

    1996-03-01

    Benthic fish bioturbation of contaminated sediments is thought to enhance exposure and, potentially, bioaccumulation into planktonic organisms. Exposures were conducted with cadmium-spiked sediment, 1.0 mg/kg nominal concentrations, and koi carp (Cyprinus carpio). Daphnia magna were placed in aquaria with and without fish for 6 d and Cd bioaccumulation was measured every 48 h. Koi carp bioturbation increased mean total suspended solids (TSS) in two trials from 0.001 mg/L to 44.4 mg/L and 19.2 mg/L to 762.4 mg/L. Mean aqueous Cd concentrations increased from1.4 {micro}g/L to 2.8 {micro}g/L, and from 1.6 {micro}g/L to 13.2 {micro}g/L. Cadmium binding capacity increased from 28.9 {micro}g/L to 169.8 {micro}g/L in with-fish treatments when compared to controls. However, Daphnia magna body burdens did not increase. Mean Cd residues of daphnids exposed with fish, 9.2 {micro}g/g, were not statistically different from without-fish exposures, 8.0 {micro}g/g. Body burdens slightly decreased in the first trial after the with-fish treatment, 9.4 {micro}g/g to 8.3 {micro}g/g. Fish size was partially correlated with TSS and aqueous Cd concentrations and TSS positively correlated with binding capacity. Because increased TSS in the with-fish treatment resulted in increased binding capacity, it is probable that cadmium bioavailability decreased. Although koi carp were capable of remobilizing Cd from sediment, Cd bioaccumulation into Daphnia magna was not significant.

  5. Methods for Estimating Adsorbed Uranium(VI) and Distribution Coefficients of Contaminated Sediments

    USGS Publications Warehouse

    Kohler, M.; Curtis, G.P.; Meece, D.E.; Davis, J.A.

    2004-01-01

    Assessing the quantity of U(VI) that participates in sorption/desorption processes in a contaminated aquifer is an important task when investigating U migration behavior. U-contaminated aquifer sediments were obtained from 16 different locations at a former U mill tailings site at Naturita, CO (U.S.A.) and were extracted with an artificial groundwater, a high pH sodium bicarbonate solution, hydroxylamine hydrochloride solution, and concentrated nitric acid. With an isotopic exchange method, both a KD value for the specific experimental conditions as well as the total exchangeable mass of U(VI) was determined. Except for one sample, KD values determined by isotopic exchange with U-contaminated sediments that were in equilibrium with atmospheric CO2 agreed within a factor of 2 with KD values predicted from a nonelectrostatic surface complexation model (NEM) developed from U(VI) adsorption experiments with uncontaminated sediments. The labile fraction of U(VI) and U extracted by the bicarbonate solution were highly correlated (r2 = 0.997), with a slope of 0.96 ?? 0.01. The proximity of the slope to one suggests that both methods likely access the same reservoir of U(VI) associated with the sediments. The results indicate that the bicarbonate extraction method is useful for estimating the mass of labile U(VI) in sediments that do not contain U(IV). In-situ KD values calculated from the measured labile U(VI) and the dissolved U(VI) in the Naturita alluvial aquifer agreed within a factor of 3 with in-situ K D values predicted with the NEM and groundwater chemistry at each well.

  6. The Behavior of Mercury in Coal Combustion Residue-Contaminated Sediments

    NASA Astrophysics Data System (ADS)

    Gofstein, T.; Heyes, A.

    2014-12-01

    Coal combustion residues (CCRs), the products of coal combustion, contain high concentrations of heavy metals such as mercury. Recent structural failures of on-site containment ponds and leaching of CCRs has potentially endangered the health of adjacent water bodies. This study examines the influence of CCR enrichment of river sediments through the study of mercury, an abundant constituent of CCRs, and the concomitant production of methylmercury. We hypothesized that CCR contamination increases the exposure to mercury for aquatic life through leaching and resuspension mechanisms. Resuspension experiments were conducted using CCR-contaminated sediments from the Dan River and uncontaminated sediments enriched with 0%, 10%, and 30% CCRs in the laboratory. Sediments were sieved to obtain the silt-clay fraction, which was then resuspended in solution with a dispersant to obtain the separate silt and clay fractions and then analyzed for total mercury concentrations. We found that CCR particles and the mercury they contain are present primarily in the silt and clay fractions of sediment and there is a direct relationship between CCR concentrations and total mercury concentrations. These findings have implications for both the bioavailability of mercury to methylating bacteria, higher organisms prone to direct ingestion of fine particles, CCR spill event remediation, current industrial waste disposal practices, and further research required in this field. Our seven day incubations of river sediment cores enriched with CCRs did not increase methylmercury in porewater above controls, suggesting that there is no immediate risk of increased methylmercury bioaccumulation, however this does not necessarily reflect the long-term effects of CCRs on river ecology, which requires further research.

  7. Bench-scale electrokinetic remediation for cesium-contaminated sediment at the Hanford Site, USA

    SciTech Connect

    Jung, Hun Bok; Yang, Jungseok; Um, Wooyong

    2015-05-01

    Electrokinetic (EK) remediation has been applied to extract various contaminants such as radionuclides, heavy metals, and organic compounds from contaminated sediment and soil using electric currents. We conducted a laboratory experiment to investigate the efficiency of EK remediation method for Hanford sediment (76% sand and 24% silt-clay) after artificial contamination with nonradioactive 133Cs (0.01 M CsNO3) as a surrogate for radioactive 137Cs. The initial 133Cs concentration in the bulk sediment was 668 mg kg-1, with a higher 133Cs concentration for the silt-clay fraction (867 mg kg-1) than for the sand fraction (83 mg kg-1). A significant removal of cationic 133Cs from the sediment occurred from the cathode side (-), whereas the removal was negligible from the anode side (+) during the EK remediation process for 68 days. Based on microwave-assisted total digestion, 312 mg kg-1 of 133Cs was removed from the bulk sediment, which corresponds to the removal efficiency of 47%. The EK method was significantly more efficient for the silt-clay fraction than for the sand fraction. X-ray diffraction (XRD) and scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) analyses indicate that change in major crystalline mineral phases was insignificant during the EK remediation and the removal of 133Cs from the Hanford sediment by the EK method is attributed mainly to cation exchange with K in clay minerals. The experimental results suggest that the EK method can effectively remove radioactive Cs from the surface or subsurface sediment contaminated by radioactive materials in the Hanford Site, Washington, USA.

  8. Binding strength-associated toxicity reduction by birnessite and hydroxyapatite in Pb and Cd contaminated sediments.

    PubMed

    Lee, Seungbae; An, Jinsung; Kim, Young-Jin; Nam, Kyoungphile

    2011-02-28

    In situ stabilization of sediment-bound heavy metals has been proposed as an alternative to ex situ treatment due to the concerns on ecosystem disturbance and remediation cost. The present study was conducted to test the performance of birnessite, hydroxyapatite, and zeolite as stabilizing agents for Pb and Cd in sediment. The heavy metal binding capacity and strength of the stabilizing agents were determined by analyzing Langmuir model parameters. The three agents showed the similar binding capacity (i.e., maximum monolayer sorption constant, K(a)) ranging from 1.13 to 3.62×10(5) mg/kg for Pb and 1.07 to 1.33×10(5) mg/kg for Cd. In contrast, binding strength (i.e., binding energy constant, b) of birnessite and hydroxyapatite was about one order higher than that of zeolite. This is further supported by five-step sequential extraction data: more than 99 and 70% of freshly spiked Pb and Cd were present as not-readily extractable fractions in birnessite and hydroxyapatite, respectively while the fractions were 17.9 and 14.1% in zeolite. Toxicity Characteristic Leaching Procedure (TCLP) test was also conducted to verify the effectiveness of the heavy metal-stabilizing ability of birnessite and hydroxyapatite. Birnessite successfully retained both Pb and Cd against the leaching solution, satisfying the TCLP extract concentration limits (i.e., 5 and 1 mg/L, respectively). However, hydroxyapatite released about 223.7 mg/L of Cd into the solution, which greatly exceeded the limit. The toxicity test with Hyalella azteca showed that their survival rate increased by 92.5-100% when birnessite or hydroxyapatite was added to Pb- or Cd-spiked sediment as a stabilizing agent. Our data demonstrate the potential use of birnessite and hydroxyapatite as an effective in situ remediation means for heavy metal-contaminated sediment with minimal risk to the aquatic ecosystem. PMID:21255927

  9. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-10-01

    Despite remediation efforts at the former nuclear weapons facility at the Hanford site (Washington State), leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a reason of continued U supply to ground water. We investigated the release of U from Hanford capillary fringe sediments to pore water. Contaminated Hanford sediments were packed into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios (1:3, 1:1, 5:1, 10:1, 25:1 mL:g). After specified times, samples were centrifuged to a gravimetric water content of 0.11 ± 0.06 g g-1. Within the first three days, there was an initial rapid release of 6-9% of total U from the sediments into the pore water, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios (1:3 and 1:1 mL:g) showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemist workbench simulations, conducted using measured solution concentrations from experiments, indicated that calcite could precipitate in the 1:3 solution-to-solid ratio experiment. After the rapid initial release in the first three days for the 5:1, 10:1, and 25:1 solution-to-solid ratio experiments, there was sustained release of U into the pore water. Up to 22% of total U was released on day 84 for the 25:1 solution-to-solid ratio reaction. This sustained release of U from the sediments had diffusion-limited kinetics.

  10. Developmental toxicity of lead-contaminated sediment in Canada geese (Branta canadensis)

    USGS Publications Warehouse

    Hoffman, David J.; Heinz, Gary H.; Sileo, Louis; Audet, Daniel J.; Campbell, Juile K.; Obrecht, Holly H., III

    2000-01-01

    Sediment ingestion has recently been identified as an important exposure route for toxicants in waterfowl. The effects of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho on posthatching development of Canada geese (Branta canadensis) were examined for 6 wk. Day-old goslings received either untreated control diet, clean sediment (48%) supplemented control diet, or CDARB sediment (3449 mug/g lead) supplemented diets at 12%, 24%, or 48%. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 0.68 ppm (ww), with over 90% depression of red blood cell ALAD activity and over fourfold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 1.61 ppm with decreased hematocrit, hemoglobin, and plasma protein in addition to the effects just described. The 48% CDARB diet resulted in blood lead of 2.52 ppm with 22% mortality, decreased growth, and elevated plasma lactate dehydrogenase-L (LDH-L) activity. In this group the liver lead concentration was 6.57 ppm (ww), with twofold increases in hepatic lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) and in reduced glutathione concentration; associated effects included elevated glutathione reductase activity but lower protein-bound thiols concentration and glucose-6-phosphate dehydrogenase (G-6-PDH) activity. The kidney lead concentration in this group was 14.93 ppm with subacute renal tubular nephrosis in one of the surviving goslings. Three other geese in this treatment group exhibited calcified areas of marrow, and one of these displayed severe chronic fibrosing pancreatitis. Lead from CDARB sediment accumulated less readily in gosling blood and tissues than reported in ducklings but at given concentrations was generally more toxic to goslings. Many of these effects were similar to those reported in wild geese and mallards within the Coeur d'Alene River Basin.

  11. Use of Isotope Dilution Method To Predict Bioavailability of Organic Pollutants in Historically Contaminated Sediments

    PubMed Central

    2015-01-01

    Many cases of severe environmental contamination arise from historical episodes, where recalcitrant contaminants have resided in the environment for a prolonged time, leading to potentially decreased bioavailability. Use of bioavailable concentrations over bulk chemical levels improves risk assessment and may play a critical role in determining the need for remediation or assessing the effectiveness of risk mitigation operations. In this study, we applied the principle of isotope dilution to quantify bioaccessibility of legacy contaminants DDT and PCBs in marine sediments from a Superfund site. After addition of 13C or deuterated analogues to a sediment sample, the isotope dilution reached a steady state within 24 h of mixing. At the steady state, the accessible fraction (E) derived by the isotope dilution method (IDM) ranged from 0.28 to 0.89 and was substantially smaller than 1 for most compounds, indicating reduced availability of the extensively aged residues. A strong linear relationship (R2 = 0.86) was found between E and the sum of rapid (Fr) and slow (Fs) desorption fractions determined by sequential Tenax desorption. The IDM-derived accessible concentration (Ce) was further shown to correlate closely with tissue residue in the marine benthic polychaete Neanthes arenaceodentata exposed in the same sediments. As shown in this study, the IDM approach involves only a few simple steps and may be readily adopted in laboratories equipped with mass spectrometers. This novel method is expected to be especially useful for historically contaminated sediments or soils, for which contaminant bioavailability may have changed significantly due to aging and other sequestration processes. PMID:24946234

  12. Use of isotope dilution method to predict bioavailability of organic pollutants in historically contaminated sediments.

    PubMed

    Jia, Fang; Bao, Lian-Jun; Crago, Jordan; Schlenk, Daniel; Gan, Jay

    2014-07-15

    Many cases of severe environmental contamination arise from historical episodes, where recalcitrant contaminants have resided in the environment for a prolonged time, leading to potentially decreased bioavailability. Use of bioavailable concentrations over bulk chemical levels improves risk assessment and may play a critical role in determining the need for remediation or assessing the effectiveness of risk mitigation operations. In this study, we applied the principle of isotope dilution to quantify bioaccessibility of legacy contaminants DDT and PCBs in marine sediments from a Superfund site. After addition of 13C or deuterated analogues to a sediment sample, the isotope dilution reached a steady state within 24 h of mixing. At the steady state, the accessible fraction (E) derived by the isotope dilution method (IDM) ranged from 0.28 to 0.89 and was substantially smaller than 1 for most compounds, indicating reduced availability of the extensively aged residues. A strong linear relationship (R2=0.86) was found between E and the sum of rapid (Fr) and slow (Fs) desorption fractions determined by sequential Tenax desorption. The IDM-derived accessible concentration (Ce) was further shown to correlate closely with tissue residue in the marine benthic polychaete Neanthes arenaceodentata exposed in the same sediments. As shown in this study, the IDM approach involves only a few simple steps and may be readily adopted in laboratories equipped with mass spectrometers. This novel method is expected to be especially useful for historically contaminated sediments or soils, for which contaminant bioavailability may have changed significantly due to aging and other sequestration processes. PMID:24946234

  13. Amendments for the in situ remediation of contaminated sediments: evaluation of potential environmental impacts.

    PubMed

    Paller, Michael H; Knox, Anna S

    2010-09-15

    Active sediment caps represent a comparatively new technology for remediating contaminated sediments. They are made by applying chemically active amendments that reduce contaminant mobility and bioavailability to the sediment surface. The objective of this study was to determine if active cap amendments including organoclay, apatite, and biopolymers have the potential to harm benthic organisms. Methods included laboratory bioassays of amendment toxicity and field evaluations of amendment impacts on organisms held in cages placed within pilot-scale active caps located in Steel Creek, a South Carolina (USA) stream. Test organisms included Hyalella azteca, Leptocheirus plumulosus, Lumbriculus variegatus, and Corbicula fluminea to represent a range of feeding modes, burrowing behaviors, and both fresh and saltwater organisms. In addition to the laboratory and field assays, chemical extractions were performed to determine if the amendments contained harmful impurities that could leach into the ambient environment. Laboratory bioassays indicated that 100% apatite had minimal effects on Hyalella in freshwater and up to 25% organoclay was nontoxic to Leptocheirus in brackish water. Field evaluations indicated that pilot-scale caps composed of up to 50% apatite and 25% organoclay did not harm Hyalella, Lumbriculus, or Corbicula. In contrast, organisms in caps containing biopolymers died because of physical entrapment and/or suffocation by the viscous biopolymers. The extractions showed that the amendments did not release harmful concentrations of metals. These studies indicated that apatite and organoclay are nontoxic at concentrations (up to 50% and 25% by weight, respectively) needed for the construction of active caps that are useful for the remediation of metals and organic contaminants in sediments. PMID:20655093

  14. A multibiomarker approach in juvenile turbot, Scophthalmus maximus, exposed to contaminated sediments.

    PubMed

    Kerambrun, E; Henry, F; Marechal, A; Sanchez, W; Minier, C; Filipuci, I; Amara, R

    2012-06-01

    Juvenile turbot were exposed in laboratory conditions to a mixture of chemical contaminants associated with harbour and estuarine sediments for seven and 21 days. Several molecular biomarkers of exposure were then measured in fish liver: two biotransformation parameters [ethoxyresorufin-O-deethylase (EROD) and phase II glutathione S-transferase (GST) activities] and an antioxidant enzyme activity [catalase (CAT)]. Modifications at the histological level were analysed by the measurement of the number and size of melanomacrophage centres (MMCs) and disturbances to the immune function by the measurement of cytokine transforming growth factor-beta (TGF-β) and development of the thymus. The responses of these molecular and immunological biomarkers were correlated with metal and PAH concentrations measured in sediments and with the physiological performance of turbot analysed in a previous study on the same fish (growth rates, condition factor K, RNA:DNA ratio and lipid index). While no difference was found in thymus analysis, some molecular and immunological responses were observed in fish exposed to contaminated sediments. Weak relationships between molecular biomarkers' responses and PAH concentrations were recorded, while their responses were significantly correlated with some metals. MMC and aggregates were weakly related to chemical contaminants whereas some significant correlations were found between TGF-b1 responses and some metal concentrations. However, molecular and immunological biomarkers were weakly related to fish physiological damages since low responses were observed in the condition which led to the lowest growth and condition indices. These data suggest the complexity of cause-effect relationships between exposure to pollutants, metabolisms and health damages. Precautions should be considered in the use of molecular and immunological biomarkers alone in biomonitoring programs. Their complementary use with physiological biomarkers, such as fish growth

  15. Remote interactive direct volume rendering of AMR data

    SciTech Connect

    Kreylos, Oliver; Weber, Gunther H.; Bethel, E. Wes; Shalf, John M.; Hamann, Bernd; Joy, Kenneth I.

    2002-03-28

    We describe a framework for direct volume rendering of adaptive mesh refinement (AMR) data that operates directly on the hierarchical grid structure, without the need to resample data onto a single, uniform rectilinear grid. The framework can be used for a range of renderers optimized for particular hardware architectures: a hardware-assisted renderer for single-processor graphics workstations, and a massively parallel software-only renderer for supercomputers. It is also possible to use the framework for distributed rendering servers. By exploiting the multiresolution structure of AMR data, the hardware-assisted renderers can render large AMR data sets at interactive rates, even if the data is stored remotely.

  16. Pressure, relaxation volume, and elastic interactions in charged simulation cells

    NASA Astrophysics Data System (ADS)

    Bruneval, Fabien; Varvenne, Céline; Crocombette, Jean-Paul; Clouet, Emmanuel

    2015-01-01

    The ab initio calculation of charged supercells within density-functional theory is a necessary step to access several important properties of matter. The relaxation volume of charged point defects or the partial molar volume of ions in solution are two such examples. However, the total energy and therefore the pressure of charged systems is not uniquely defined when periodic boundary conditions are employed. This problem is tightly related to the origin of the electrostatic potential in periodic systems. This effect can be easily observed by modifying the electrostatic convention or modifying the local ionic potential details. We propose an approach to uniquely define the pressures in charged supercells with the use of the absolute deformation potentials. Only with such a definition could the ab initio calculations provide meaningful values for the relaxation volumes and for the elastic interactions for charged defects in semiconductors or ions in solution. The proposed scheme allows one to calculate sensible data even when charge neutrality is not enforced, thus going beyond the classical force-field-based approaches.

  17. Fast global interactive volume segmentation with regional supervoxel descriptors

    NASA Astrophysics Data System (ADS)

    Luengo, Imanol; Basham, Mark; French, Andrew P.

    2016-03-01

    In this paper we propose a novel approach towards fast multi-class volume segmentation that exploits supervoxels in order to reduce complexity, time and memory requirements. Current methods for biomedical image segmentation typically require either complex mathematical models with slow convergence, or expensive-to-calculate image features, which makes them non-feasible for large volumes with many objects (tens to hundreds) of different classes, as is typical in modern medical and biological datasets. Recently, graphical models such as Markov Random Fields (MRF) or Conditional Random Fields (CRF) are having a huge impact in different computer vision areas (e.g. image parsing, object detection, object recognition) as they provide global regularization for multiclass problems over an energy minimization framework. These models have yet to find impact in biomedical imaging due to complexities in training and slow inference in 3D images due to the very large number of voxels. Here, we define an interactive segmentation approach over a supervoxel space by first defining novel, robust and fast regional descriptors for supervoxels. Then, a hierarchical segmentation approach is adopted by training Contextual Extremely Random Forests in a user-defined label hierarchy where the classification output of the previous layer is used as additional features to train a new classifier to refine more detailed label information. This hierarchical model yields final class likelihoods for supervoxels which are finally refined by a MRF model for 3D segmentation. Results demonstrate the effectiveness on a challenging cryo-soft X-ray tomography dataset by segmenting cell areas with only a few user scribbles as the input for our algorithm. Further results demonstrate the effectiveness of our method to fully extract different organelles from the cell volume with another few seconds of user interaction.

  18. Characterization of U(VI) reduction in contaminated sediments with slow-degrading electron donor source

    NASA Astrophysics Data System (ADS)

    Wu, W.; Watson, D. B.; Zhang, G.; Mehlhorn, T.; Lowe, K.; Earles, J.; Phillips, J.; Kelly, S. D.; Boyanov, M.; Kemner, K. M.; Schadt, C.; Criddle, C. S.; Jardine, P. M.; Brooks, S. C.

    2011-12-01

    In order to select sustainable, high efficiency and cost effective electron donor source, oleate and emulsified vegetable oil (EVO) were tested uranium (VI) reduction in comparison with ethanol in microcosms using uranium contaminated sediments and groundwater from the US DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site. The effect of initial sulfate concentration on U(VI) reduction was also tested. Both oleate and EVO were effective electron donor sources for U(VI) reduction. Accumulation of acetate as a major product and the removal of aqueous U(VI) were observed and were associated with sulfate reduction. Both oleate and EVO supported U(VI) reduction but at slower rates with a comparable but slightly lower extent of reduction than ethanol. X-ray absorption near-edge spectroscopy (XANES) analysis confirmed reduction of U(VI) to U(IV). The extent of U(VI) reduction in solid phase was negatively influenced by aqueous calcium concentration. The majority of electrons of the three substrates were consumed by sulfate reduction, Fe(III) reduction, and methanogenesis. Initial U(VI) concentration in the aqueous phase increased with increased sulfate concentration (1 versus 5 mM), likely due to U(VI) desorption from the solid phase. At the higher initial sulfate concentration more U(VI) was reduced and fewer electrons were used in methanogenesis. Analysis of bacterial and archeal populations using 16S rRNA gene libraries showed a significant increase in Deltaproteobacteria after biostimulation. The microbial community structures developed with oleate and EVO were significantly distinct from those developed with ethanol. Bacteria similar to Desulforegula spp. was predominant for oleate and EVO degradation but were not observed in ethanol-amended microcosms. Known U(VI)-reducing bacteria in the microcosms amended with the three electron donor sources included iron(III) reducing Geobacter spp. but in lower abundances than sulfate-reducing Desulfovibrio spp. The

  19. Phosphorus amendment reduces hepatic and renal oxidative stress in mallards ingesting lead-contaminated sediments

    USGS Publications Warehouse

    Hoffman, D.J.; Heinz, G.H.; Audet, D.J.

    2006-01-01

    Lead poisoning of waterfowl has been reported for decades in the Coeur d'Alene River Basin (CDARB) in Idaho as a result of the ingestion of lead-contaminated sediments. This study was conducted to determine whether the addition of phosphoric acid to CDARB sediments would reduce the bioavailability and toxicity of lead to the liver and kidney of mallards (Anas platyrhynchos). Mallards received diets containing 12% clean sediment (controls) or 12% sediment from three different CDARB sites containing 4520, 5390, or 6990 ug/g lead (dry weight) with or without phosphoric acid amendment. Liver and kidney lead concentrations were significantly higher in all CDARB treatment groups and ranged from geometric mean values of 18.2 (liver) and 28.7 (kidney) for the first 2 sites to 22.5 (liver) and 45.6 (kidney) ug/g (wet weight) for the third site. With amendments all liver lead concentrations were reduced 36 to 55%, and all kidney lead concentrations were lowered 54 to 73%. Unamended CDARB sediment from the third site resulted in the following hepatic effects: over 1.6-fold elevation of liver glutathione (reduced form; GSH) concentration, higher GSH S-transferase and oxidized glutathione (GSSG) reductase activities, and lower protein-bound thiols (PBSH) concentration. Renal effects included higher kidney GSH concentrations for all CDARB sites, with over 2.1-fold higher for the third site. Resulting kidney GSSG to GSH ratios were lower at two sites. At the third site, gamma-glutamyl transferase (GGT) activity was elevated, and lipid peroxidation as thiobarbituric acid-reactive substances (TBARS) was 1.7-fold greater. Amendment restored all hepatic variables as well as the renal variables TBARS and GGT so they did not differ from controls. Although amendments of phosphorus substantially reduced the bioavailability of lead and some of the adverse effects, lead concentrations in the tissues of mallards fed the amended sediments were still above those considered to be harmful to

  20. Contaminated Sediment Management in Dam Removals and River Restoration Efforts: Critical Need for Research and Policy Development

    NASA Astrophysics Data System (ADS)

    Evans, J. E.

    2015-12-01

    Over 1,000 U.S. dams have been removed (1975-2015) for reasons including obsolescence, liability concerns, water quality upgrades, fisheries, or ecosystem enhancements. Contaminated sediment can significantly complicate the approval process, cost, and timeline of a dam removal, or stop it entirely. In a dam removal, reservoir sediment changes from a sink to a source of contaminants. Recently, the Sierra Club sued to stop the removal of a large dam in Ohio because of the potential impact of phosphate releases on toxic algal blooms in Lake Erie. Heavy metals, PCBs, PAHs, pesticides, and petroleum hydrocarbons can be present in reservoir sediments. In a non-dam removal scenario, reservoir management tools range from "no action" to dredging, dewatering and removal, or sediment capping. But it is not clear how these reservoir management techniques apply to dam removals. Case studies show typically >80% of the reservoir sediment is eventually eroded, precluding sediment capping as a containment option. However, the released contaminants are diluted by mixing with "clean" sediment and are transported to different physio-chemical environments which may immobilize or biodegrade the contaminants. Poorly understood options include phased drawdown/reseeding the former reservoir to contain sediments, diking contaminant "hot spots," and addressing contaminant stratigraphy (where historical use created "hot layers" in the reservoir sediment). Research and policy development needs include: (1) assessment methods based on synergistic effects of multiple contaminants being present; (2) ways to translate the pre-removal contaminant concentrations to post-removal health risks downstream; (3) evaluation of management practices for contaminant "hot spots" and "hot layers;" (4) tools to forecast the presence of contaminated sediment using easily accessible information; and (5) ways to limit liability risk for organizations participating in dam removals involving contaminated sediment.

  1. Stroke volume during exercise: interaction of environment and hydration.

    PubMed

    González-Alonso, J; Mora-Rodríguez, R; Coyle, E F

    2000-02-01

    Euhydrated and dehydrated subjects exercised in a hot and a cold environment with our aim to identify factors that relate to reductions in stroke volume (SV). We hypothesized that reductions in SV with heat stress are related to the interaction of several factors rather than the effect of elevated skin blood flow. Eight male endurance-trained cyclists [maximal O(2) consumption (VO(2 max)) 4.5 +/- 0.1 l/min; means +/- SE] cycled for 30 min (72% VO(2 max)) in the heat (H; 35 degrees C) or the cold (C; 8 degrees C) when euhydrated or dehydrated by 1.5, 3.0, or 4.2% of their body weight. When euhydrated, SV and esophageal temperature (T(es) 38. 2-38.3 degrees C) were similar in H and C, whereas skin blood flow was much higher in H vs. C (365 +/- 64% higher; P < 0.05). With each 1% body weight loss, SV declined 6.4 +/- 1.3 ml (4.8%) in H and 3.4 +/- 0.4 ml (2.5%) in C, whereas T(es) increased 0.21 +/- 0.02 and 0. 10 +/- 0.02 degrees C in H and C, respectively (P < 0.05). However, reductions in SV were not associated with increases in skin blood flow. The reduced SV was highly associated with increased heart rate and reduced blood volume in both H (R = 0.96; P < 0.01) and C (R = 0. 85; P < 0.01). In conclusion, these results suggest that SV is maintained in trained subjects during exercise in euhydrated conditions despite large differences in skin blood flow. Furthermore, the lowering of SV with dehydration appears largely related to increases in heart rate and reductions in blood volume. PMID:10666060

  2. Dispersion and Excluded Volume Interactions in Nematic Liquid Crystals.

    NASA Astrophysics Data System (ADS)

    Poliks, Mark David

    1988-12-01

    The effectiveness of the potential of mean torque in accounting for solute orientation is explored. It is described by repulsive (excluded volume) and attractive forces (dispersion) and is tested using rigid, semi-flexible and flexible solutes dissolved in nematic phases. For rigid molecules (benzenes and anthracene) the attractive short range potential gave the best results. For anthracene the results indicated that the potential can discriminate between solute/solvent interactions. For wholly aliphatic solvents the excluded volume forces gave excellent agreement, as did the attractive forces for the aromatic solvents. For the semi-flexible molecule, biphenyl, quadrupole splittings were simulated using the internal torsion angle as a parameter. The values of this angle were predicted to vary systematically with temperature. Using crystallographic and idealized structural data as the starting points for the calculation, the structure of PAA in the nematic phase was estimated. Both the internal angle and the aromatic proton valence angles were determined. Flexible, "siamese-twin" liquid crystals having an internal per-deuterated spacer consisting of ten methylenes were studied. They differed only in the length of the aliphatic tails (5105, 101010). The quadrupole splittings of both twins dissolved in the nematic phase of BCH-S1131 were identical. Quantitative simulations of the splittings using standard RIS geometry and excluded volume forces were successful. In the bulk nematic phase the order parameter of 5105 was greater than 101010. The difference was interpreted as a dilution effect of the mesogenic cores by aliphatic tails. Simulations indicated the conformation of the spacer is highly extended. As parameterized the required strength of the mean field is a strong function of the molecular dimensions, suggesting that the current description still is incomplete.

  3. INNOVATIVE IN-SITU REMEDIATION OF CONTAMINATED SEDIMENTS FOR SIMULTANEOUS CONTROL OF CONTAMINATION AND EROSION

    SciTech Connect

    Knox, A; Michael Paller, M; Danny D. Reible, D; Ioana G. Petrisor, I

    2007-11-28

    New technologies are needed that neutralize contaminant toxicity and control physical transport mechanisms that mobilize sediment contaminants. The last 12 months of this comprehensive project investigated the use of combinations of sequestering agents to develop in situ active sediment caps that stabilize mixtures of contaminants and act as a barrier to mechanical disturbance under a broad range of environmental conditions. Efforts focused on the selection of effective sequestering agents for use in active caps, the composition of active caps, and the effects of active cap components on contaminant bioavailability and retention. Results from this project showed that phosphate amendments, some organoclays, and the biopolymer, chitosan, were very effective at removing metals from both fresh and salt water. These amendments also exhibited high retention (80% or more) of most metals indicating reduced potential for remobilization to the water column. Experiments on metal speciation and retention in contaminated sediment showed that apatite and organoclay can immobilize a broad range of metals under both reduced and oxidized conditions. These studies were followed by sequential extractions to evaluate the bioavailability and retention of metals in treated sediments. Metal fractions recovered in early extraction steps are more likely to be bioavailable and were termed the Potentially Mobile Fraction (PMF). Less bioavailable fractions collected in later extraction steps were termed the Recalcitrant Factor (RF). Apatite and organoclay reduced the PMF and increased the RF for several elements, especially Pb, Zn, Ni, Cr, and Cd. Empirically determined partitioning coefficients and modeling studies were used to assess the retention of organic contaminants on selected sequestering agents. Organoclays exhibited exceptionally high sorption of polycyclic aromatic hydrocarbons as indicated by a comparison of K{sub d} values among 12 amendments. These results suggested that

  4. Reduced growth of rainbow trout (Oncorhynchus mykiss) fed a live invertebrate diet pre-exposed to metal-contaminated sediments.

    PubMed

    Hansen, James A; Lipton, Joshua; Welsh, Paul G; Cacela, David; MacConnell, Beth

    2004-08-01

    Juvenile rainbow trout (Oncorhynchus mykiss) were fed live diets of Lumbriculus variegatus cultured in metal-contaminated sediments from the Clark Fork River Basin (MT, USA), an uncontaminated reference sediment, or an uncontaminated culture medium. Fish were tested in individual chambers; individual growth as well as the nutritional quality and caloric value of each trout's consumed diet were determined. Growth was measured following 14, 28, 42, 56, and 67 d of exposure. A subset of fish was sampled at 35 d for whole-body metals. Metals (whole body, digestive tract, and liver) and histology were measured at the end of the test. We observed significant growth inhibition in trout fed the contaminated diets; growth inhibition was associated with reductions in conversion of food energy to biomass rather than with reduced food intake. Growth inhibition was negatively correlated with As in trout tissue residues. Histological changes in contaminated treatments included hepatic necrosis and degenerative alterations in gallbladder. The present study provides evidence that metal-contaminated sediments can pose a hazard to trout health through a dietary exposure pathway. PMID:15352479

  5. The role of biomarkers to assess oil-contaminated sediment quality using toxicity tests with clams and crabs.

    PubMed

    Morales-Caselles, Carmen; Martín-Díaz, María Laura; Riba, Inmaculada; Sarasquete, Carmen; Delvalls, Tomás Angel

    2008-06-01

    A 28-d bioassay was conducted with two invertebrate species with different feeding habits, the clam Ruditapes philippinarum and the shore crab Carcinus maenas. The purpose of the present study was to assess the quality of sediments affected by oil spills in different areas of the Spanish coast. The organisms were exposed to environmental samples of oil-contaminated sediments during four weeks and, after the experiment, a suite of biomarkers of exposure was measured: The phase one detoxification system was assessed by ethoxyresorufin-O-deethylase (EROD) activity; glutathione-S-transferase (GST) is a phase-two detoxification enzyme but also is implicated in oxidative stress events; glutathione peroxidase (GPX), glutathione reductase (GR), and the ferric reducing ability of plasma (FRAP) assay were analyzed to determine the antioxidant activity of the tissues. The biomarker results were correlated with the chemical compounds bound to sediments (polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], Zn, Cd, Pb, Cu, Ni, Co, V) and a principal component analysis was carried out with the purpose of linking all the variables and to detect those contaminated sediments potentially harmful to the biota. Results showed induction of biomarkers in both invertebrate species and significant differences (p < 0.05; p < 0.01) were established among sediments affected by different spills. The use of the selected biomarkers together with the sediment chemical analysis assesses the bioavailability of contaminants and has proven to be a suitable tool to monitor the environmental quality of sediments affected by oil spills. PMID:18198936

  6. Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

    PubMed

    Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

    2015-06-01

    Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (<63 μm) from clean and contaminated field sites to create 4 treatments of increasing metal concentrations. Sydney rock oysters were then exposed to sediment treatments at different TSS concentrations for 4 d, and cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. PMID:25677686

  7. Development, Evaluation, and Application of Sediment Quality Targets for Assessing and Managing Contaminated Sediments in Tampa Bay, Florida

    USGS Publications Warehouse

    MacDonald, D.D.; Carr, R.S.; Eckenrod, D.; Greening, H.; Grabe, S.; Ingersoll, C.G.; Janicki, S.; Janicki, T.; Lindskoog, R.A.; Long, E.R.; Pribble, R.; Sloane, G.; Smorong, D.E.

    2004-01-01

    Tampa Bay is a large, urban estuary that is located in west central Florida. Although water quality conditions represent an important concern in this estuary, information from numerous sources indicates that sediment contamination also has the potential to adversely affect aquatic organisms, aquatic-dependent wildlife, and human health. As such, protecting relatively uncontaminated areas of the bay from contamination and reducing the amount of toxic chemicals in contaminated sediments have been identified as high-priority sediment management objectives for Tampa Bay. To address concerns related to sediment contamination in the bay, an ecosystem-based framework for assessing and managing sediment quality conditions was developed that included identification of sediment quality issues and concerns, development of ecosystem goals and objectives, selection of ecosystem health indicators, establishment of metrics and targets for key indicators, and incorporation of key indicators, metrics, and targets into watershed management plans and decision-making processes. This paper describes the process that was used to select and evaluate numerical sediment quality targets (SQTs) for assessing and managing contaminated sediments. These SQTs included measures of sediment chemistry, whole-sediment and pore-water toxicity, and benthic invertebrate community structure. In addition, the paper describes how the SQTs were used to develop site-specific concentration-response models that describe how the frequency of adverse biological effects changes with increasing concentrations of chemicals of potential concern. Finally, a key application of the SQTs for defining sediment management areas is discussed.

  8. Real-time x-ray absorption spectroscopy of uranium, iron, and manganese in contaminated sediments during bioreduction

    SciTech Connect

    Tokunaga, Tetsu; Tokunaga, T.K.; Wan, J.; Kim, Y.; Sutton, S.R.; Newville, M.; Lanzirotti, A.; Rao, W.

    2008-01-15

    The oxidation status of uranium in sediments is important because the solubility of this toxic and radioactive element is much greater for U(VI) than for U(IV) species. Thus, redox manipulation to promote precipitation of UO{sub 2} is receiving interest as a method to remediate U-contaminated sediments. Presence of Fe and Mn oxides in sediments at much higher concentrations than U requires understanding of their redox status as well. This study was conducted to determine changes in oxidation states of U, Fe, and Mn in U-contaminated sediments from Oak Ridge National Laboratory. Oxidation states of these elements were measured in real-time and nondestructively using X-ray absorption spectroscopy, on sediment columns supplied with synthetic groundwater containing organic carbon (OC, 0, 3, 10, 30 and 100 mM OC as lactate) for over 400 days. In sediments supplied with OC {ge} 30 mM, 80% of the U was reduced to U(IV), with transient reoxidation at about 150 days. Mn(III,IV) oxides were completely reduced to Mn(II) in sediments infused with OC {ge} 3 mM. However, Fe remained largely unreduced in all sediment columns, showing that Fe(III) can persist as an electron acceptor in reducing sediments over long times. This result in combination with the complete reduction of all other potential electron acceptors supports the hypothesis that the reactive Fe(III) fraction was responsible for reoxidizing U(IV).

  9. Modeling the effects and uncertainties of contaminated sediment remediation scenarios in a Norwegian fjord by Markov chain Monte Carlo simulation.

    PubMed

    Saloranta, Tuomo M; Armitage, James M; Haario, Heikki; Naes, Kristoffer; Cousins, Ian T; Barton, David N

    2008-01-01

    Multimedia environmental fate models are useful tools to investigate the long-term impacts of remediation measures designed to alleviate potential ecological and human health concerns in contaminated areas. Estimating and communicating the uncertainties associated with the model simulations is a critical task for demonstrating the transparency and reliability of the results. The Extended Fourier Amplitude Sensitivity Test(Extended FAST) method for sensitivity analysis and Bayesian Markov chain Monte Carlo (MCMC) method for uncertainty analysis and model calibration have several advantages over methods typically applied for multimedia environmental fate models. Most importantly, the simulation results and their uncertainties can be anchored to the available observations and their uncertainties. We apply these techniques for simulating the historical fate of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Grenland fjords, Norway, and for predicting the effects of different contaminated sediment remediation (capping) scenarios on the future levels of PCDD/Fs in cod and crab therein. The remediation scenario simulations show that a significant remediation effect can first be seen when significant portions of the contaminated sediment areas are cleaned up, and that increase in capping area leads to both earlier achievement of good fjord status and narrower uncertainty in the predicted timing for this. PMID:18350897

  10. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    NASA Astrophysics Data System (ADS)

    Williams, Steven M.; Ashbaugh, Henry S.

    2014-01-01

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  11. Note: Nonpolar solute partial molar volume response to attractive interactions with water

    SciTech Connect

    Williams, Steven M.; Ashbaugh, Henry S.

    2014-01-07

    The impact of attractive interactions on the partial molar volumes of methane-like solutes in water is characterized using molecular simulations. Attractions account for a significant 20% volume drop between a repulsive Weeks-Chandler-Andersen and full Lennard-Jones description of methane interactions. The response of the volume to interaction perturbations is characterized by linear fits to our simulations and a rigorous statistical thermodynamic expression for the derivative of the volume to increasing attractions. While a weak non-linear response is observed, an average effective slope accurately captures the volume decrease. This response, however, is anticipated to become more non-linear with increasing solute size.

  12. An experimental and modeling study of grain-scale uranium desorption from field-contaminated sediments and the potential influence of microporosity on mass-transfer

    NASA Astrophysics Data System (ADS)

    Stoliker, D.; Liu, C.; Kent, D. B.; Zachara, J. M.

    2012-12-01

    The aquifer below the 300-Area of the Hanford site (Richland, WA, USA) is plagued by a persistent plume of dissolved uranium (U(VI)) in excess of the Environmental Protection Agency drinking water maximum contamination level even after the removal of highly contaminated sediments. The aquifer sediments in the seasonally saturated lower vadose zone act as both a source and sink for uranium during stage changes in the nearby Columbia River. Diffusion limitation of uranium mass-transfer within these sediments has been cited as a potential cause of the plume's persistence. Equilibrium U(VI) sorption is a strong function of variable chemical conditions, especially carbonate, hydrogen, and uranyl ion activities. Field-contaminated sediments from the site require up to 1,000 hours to reach equilibrium in static batch reactors. Increases in U(VI) concentrations over longer time-scales result from changes in chemical conditions, which drive reactions with sediments that favor U(VI) desorption. Grain-scale U(VI) sorption/desorption rates are slow, likely owing to diffusion of U(VI) and other solutes through intra-granular pore domains. In order to improve understanding of the impact of intra-granular diffusion and chemical reactions controlling grain-scale U(VI) release, experiments were conducted on individual particle size fractions of a <8 mm composite of field-contaminated, lower vadose zone sediments. For each size fraction, equilibrium U(VI) sorption/desorption in static batch reactors was well-described by surface complexation models over a range of chemical conditions applicable to the field site. Desorption rates from individual size fractions in flow-through batch reactors, examined under a single set of constant chemical conditions with multiple stop-flow events, were similar for all size fractions <2 mm. Kinetic U(VI) desorption in flow-through batch reactors was modeled using a multi-rate surface complexation approach, where sorption/desorption rates were

  13. Magnetic Interaction and Switching Volumes in CoSm/Cr Magnetic Films

    NASA Astrophysics Data System (ADS)

    Jeong, Soon Young; Kim, Hyeon Soo; Kim, Sang In; Lee, Jong Duk; Shu, Su Jeong

    2006-06-01

    The sputtering pressure dependence of magnetic switching volume and the nature of magnetic intergranular interaction in CoSm/Cr films have been investigated using several magnetic characterization techniques. As the results, we found that magnetic switching volume strongly correlates to the nature and strength of magnetic intergranular interaction determined on the basis of dc demagnetization remanence and isothermal remanence curves. Also the sign of interaction field factor is closely related to the nature of magnetic intergranular interaction.

  14. Long-term effects of dredging operations program: Assessing bioaccumulation in aquatic organisms exposed to contaminated sediments. Final report

    SciTech Connect

    Clarke, J.U.; McFarland, V.A.

    1991-07-01

    This paper synthesizes previous work on bioaccumulation to provide a working document for the environmental impact on the aquatic environment due to bioaccumulation of sediment contaminants resulting from dredging operations and dredged material placement. Emphasis is placed on explanation of basic concepts concerning, and factors influencing, sediment contaminant bioaccumulation and bioavailability. The paper presents several numerical methods for assessing bioaccumulation, including a simple method for estimating theoretical bioaccumulation potential (TBP) from sediment chemistry for neutral organic chemicals. Methods are also given for projecting contaminant concentrations in organism tissues when steady state is achieved, based on laboratory or field exposures to contaminated sediments. These assessments are presented in the context of the US Environmental Protection Agency's tiered testing approach for dredged material evaluation. The various numerical methods for bioaccumulation assessment are illustrated and compared using step-by-step example calculations with hypothetical and actual data.

  15. Metabolic and genomic analysis elucidates strain-level variation in Microbacterium spp. isolated from chromate contaminated sediment

    PubMed Central

    Henson, Michael W.; Santo Domingo, Jorge W.; Kourtev, Peter S.; Jensen, Roderick V.; Dunn, James A.

    2015-01-01

    Hexavalent chromium [Cr(VI)] is a soluble carcinogen that has caused widespread contamination of soil and water in many industrial nations. Bacteria have the potential to aid remediation as certain strains can catalyze the reduction of Cr(VI) to insoluble and less toxic Cr(III). Here, we examine Cr(VI) reducing Microbacterium spp. (Cr-K1W, Cr-K20, Cr-K29, and Cr-K32) isolated from contaminated sediment (Seymore, Indiana) and show varying chromate responses despite the isolates’ phylogenetic similarity (i.e., identical 16S rRNA gene sequences). Detailed analysis identified differences based on genomic metabolic potential, growth and general metabolic capabilities, and capacity to resist and reduce Cr(VI). Taken together, the discrepancies between the isolates demonstrate the complexity inter-strain variation can have on microbial physiology and related biogeochemical processes. PMID:26587353

  16. Ecological effects of contaminated sediments following a decade of no industrial effluents emissions: the Sediment Quality Triad approach.

    PubMed

    Lopes, Marta Lobão; Rodrigues, Ana Maria; Quintino, Victor

    2014-10-15

    Sediments contaminated by industrial effluents a decade after the emissions were stopped were statistically compared to sediments from reference channels, using the Sediment Quality Triad approach. The metals and metalloid concentrations, mainly Hg and As, increased towards the upper part of a contaminated channel, where the industrial discharge was located. A bioaccumulation assay with Scrobicularia plana showed the highest bioaccumulation and mortality in the most contaminated sediments and bioaccumulation strongly correlated with the sediments metals and metalloid concentrations. The resident macroinvertebrate community also showed significant differences between the contaminated and reference channels, in the upper areas, where the community was most affected. All three elements of the quality triad rejected the null hypothesis and indicated that despite the emissions ceasing in 2004, sediments remain contaminated by high levels of metals and metalloid, leading to bioaccumulation and with severe community level consequences. PMID:25152187

  17. Liposome technology. Volume III: Targeted drug delivery and biological interaction

    SciTech Connect

    Gregoriadis, G.

    1984-01-01

    These three volumes cover liposome technology in pharmacology and medicine. Contributors emphasize methodology used in their own laboratories, and include a brief introduction, coverage of relevant literature, applications and critical evaluations for the methods they describe. In Volume III, the growing variety of techniques yielding targeted liposomes and approaches of studying liposomal behavior both in vitro and in vivo are discussed.

  18. Draft Genome Sequence of Alkane-Degrading Acinetobacter venetianus JKSF02, Isolated from Contaminated Sediment of the San Jacinto River in Houston, Texas.

    PubMed

    Iyer, Rupa; Damania, Ashish

    2016-01-01

    Acinetobacter venetianusJKSF02 was isolated from contaminated sediment in eastern Houston, Texas along the San Jacinto River. This microorganism specializes in n-alkane degradation and is well suited for bioremediation of the petroleum hydrocarbon deposited throughout the region by shipping and industrial activity from the Houston Ship Channel. PMID:27081144

  19. Distinguishing Betwen Effects of Local Inputs (Contaminated Sediments, Point Sources) and Upstream Diffuse Nonpoint Source Input: Refinement of a Watershed Development Index for New England

    EPA Science Inventory

    Assessment tools are being developed to predict diffuse NPS effects from watershed development and distinguish these from local impacts (point sources, contaminated sediments). Using EMAP data from the New England Wadeable Stream Survey and two state datasets (CT, ME), we are de...

  20. Draft Genome Sequence of Alkane-Degrading Acinetobacter venetianus JKSF02, Isolated from Contaminated Sediment of the San Jacinto River in Houston, Texas

    PubMed Central

    Damania, Ashish

    2016-01-01

    Acinetobacter venetianus JKSF02 was isolated from contaminated sediment in eastern Houston, Texas along the San Jacinto River. This microorganism specializes in n-alkane degradation and is well suited for bioremediation of the petroleum hydrocarbon deposited throughout the region by shipping and industrial activity from the Houston Ship Channel. PMID:27081144

  1. NATIONAL CONFERENCE ON MANAGEMENT AND TREATMENT OF CONTAMINATED SEDIMENTS PROCEEDINGS CINCINNATI, OH MAY 13-14, 1997 (EPA/600/R-98/001)

    EPA Science Inventory

    The National Conference on Management and Treatment of Contaminated Sediment was held in Cincinnati, OH, May 13 to 14, 1997. This technology transfer meeting was held for 213 professionals from various EPA divisions and other organizations, including Environment Canada, the U.S. ...

  2. Survival, growth, and body residues of Hyalella azteca (Saussure) exposed to fipronil contaminated sediments from non-vegetated and vegetated microcosms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed chronic effects of fipronil and metabolite contaminated sediments from non-vegetated and Thallia dealbata vegetated wetland microcosms on Hyalella azteca during wet and dry exposures. Mean sediment concentrations (ng g-1) ranged from 0.72-1.26, 0.01-0.69, 0.07-0.23, and 0.49-7.87 for fip...

  3. EFFECTS OF A CONTAMINATED SEDIMENT ON LIFE HISTORY TRAITS AND POPULATION GROWTH RATE OF NEANTHES ARENACEODENTATA (POLYCHAETA:NEREIDAE) IN THE LABORATORY

    EPA Science Inventory

    The effects of a highly contaminated sediment on life history traits and population dynamics of the nereid polychaete Neanthes arenaceodentata Moore were assessed in a laboratory experiment. Survival, growth and fecundity were measured for one generation of worms exposed to 40 an...

  4. Interactive pre-integrated volume rendering of medical datasets

    NASA Astrophysics Data System (ADS)

    Kye, Heewon; Hong, Helen; Shin, Yeong-Gil

    2005-04-01

    The pre-integrated volume rendering which produces high-quality images with less sampling has become one of the most efficient and important techniques in volume rendering field. In this paper, we propose an acceleration technique of pre-integrated rendering of dynamically classified volumes. Using the overlapped-min-max block, empty space skipping of ray casting can be applied in pre-integrated volume rendering. In addition, a new pre-integrated lookup table brings much fast rendering of high-precision data without degrading image quality. We have implemented our approaches not only on the consumer graphics hardware but also on CPU, and show the performance gains using several medical data sets.

  5. Interactive volume rendering of multimodality 4D cardiac data with the use of consumer graphics hardware

    NASA Astrophysics Data System (ADS)

    Enders, Frank; Strengert, Magnus; Iserhardt-Bauer, Sabine; Aladl, Usaf E.; Slomka, Piotr J.

    2003-05-01

    Interactive multimodality 4D volume rendering of cardiac images is challenging due to several factors. Animated rendering of fused volumes with multiple lookup tables (LUT) and interactive adjustments of relative volume positions and orientations must be performed in real time. In addition it is difficult to visualize the myocardium separated from the surrounding tissue on some modalities, such as MRI. In this work we propose to use software techniques combined with hardware capabilities of modern consumer video cards for real-time visualization of time-varying multimodality fused cardiac volumes for diagnostic purposes.

  6. Robot technology: Interaction with the environment. Volume 2

    SciTech Connect

    Coiffet, P.

    1984-01-01

    This book explains the steps that need to be taken in the making of the advanced robot. The advanced robot is defined as the robot that senses and reacts to changes in its environment. It provides comprehensive survey and description of the problems posed by the detection of stress, tactile and proximetric detection, and artificial vision, all essential to the development and understanding of the adaptive robot. It also provides an excellent summary of techniques, practical and mathematical, needed to deal with them. This book provides an indispensible source of reference for both designers and users of robots. The contents are, introduction; characteristics of robots adaptable to environmental variations interaction to weight surrounding medium and workload, interactions involving physical contact between robot and environment; the detection of stress, interactions physical contact between robot and environment; tactile detection, remote interaction: proximity sensing, remote interaction, artificial vision, remote sensing: artificial vision-representation of visual information. Remote sensing: artificial vision.

  7. Developing Rapid and Cost-Effective Tools for Assessing Groundwater Impacts on Contaminated Sediments

    EPA Science Inventory

    This research developed quick and inexpensive methods that can be useful in characterizing the interaction of water and solids within the GW/SW transition zone to explain processes that occur during physical contact between groundwater and sediments. The research used self-conta...

  8. Determining the Desorption Kinetics of U(VI) from Contaminated Sediments Under Complex and Changing Solution Conditions

    NASA Astrophysics Data System (ADS)

    Hay, M. B.; Curtis, G. P.; Johnson, K. J.; Greskowiak, J.; Davis, J. A.

    2009-12-01

    Uranium(VI) transport in contaminated sediments is strongly controlled by the thermodynamics and kinetics of adsorption on mineral surfaces. Many studies on natural sediments and synthetic mineral phases have demonstrated the dependence of U(VI) sorption equilibrium on aqueous chemical conditions, with alkalinity, pH, ionic strength, and Ca concentration of particular importance in many natural systems. Desorption of U(VI) from contaminated sediments from DOE sites in Hanford, WA, Rifle, CO, and Naturita, CO also exhibits a significant kinetic limitation, with timescales of several weeks to months required to reach desorption equilibrium in some cases. This kinetic limitation is believed to be due to diffusion in intragranular pore space, which includes small fractures within grains and pores within clay aggregates and grain coatings. Development of appropriate reactive transport models that can be applied to predict the fate and transport of U(VI) in contaminated aquifers relies on accurately quantifying sorption equilibrium and kinetics at the grain scale, which vary from site to site based on sediment characteristics. This analysis typically involves laboratory batch- and column-scale adsorption/desorption experiments performed under a variety of chemical conditions to fully constrain surface complexation and kinetic models, requiring a constant set of chemical conditions over the duration of the experiment. In practice, however, this can be difficult in experiments aiming to quantify long-term kinetics (weeks to months time scale), due to slow ion exchange, mineral dissolution/precipitation, and redox processes. Long-term changes in solution conditions affect U(VI) sorption equilibrium, making it necessary to determine model parameters for U(VI) surface complexation, diffusion kinetics, and chemical weathering/ion exchange processes simultaneously from a given data set. We will present kinetic surface complexation model results obtained for size

  9. Bioavailability of Chlorocatechols in Naturally Contaminated Sediment Samples and of Chloroguaiacols Covalently Bound to C2-Guaiacyl Residues

    PubMed Central

    Allard, Ann-Sofie; Hynning, Per-Åke; Remberger, Mikael; Neilson, Alasdair H.

    1994-01-01

    Bacteria in anaerobic enrichment cultures that dechlorinated a range of chlorocatechols were used to examine the stability of endogenous chlorocatechols in a contaminated sediment sample and in interstitial water prepared from it. During incubation of the sediment sample for 450 days with or without added cells, there was a decrease in the concentration of solvent-extractable chlorocatechols but not in that of the total chlorocatechols, including sediment-associated components. In the presence of azide, the decrease in the concentrations of the former was eliminated or substantially decreased. Control experiments in which 3,4,5-trichlorocatechol was added to the sediment suspensions after 130 days showed that its dechlorination was accomplished not only by the added cells but also by the endemic microbial flora. It was concluded that the endogenous chlorocatechols in the sediment were not accessible to microorganisms with dechlorinating activity. On the other hand, microorganisms were apparently responsible for decreasing the solvent extractability of the chlorocatechols, and this effect decreased with increasing length of exposure time. Similar experiments carried out for 70 days with the sediment interstitial water showed that the chlorocatechols that were known to be associated with organic matter were also inaccessible to microbial dechlorination. Experiments with model compounds in which 4,5,6-trichloroguaiacol and tetrachloroguaiacol were covalently linked to C2-guaiacyl residues showed that these compounds were resistant to O demethylation or dechlorination during incubation with a culture having these activities. The only effect of microbial action was the quantitative reduction in 12 days of the C′1 keto group to an alcohol which was stable against further transformation for up to 65 days. The results of these experiments are consistent with the existence of chlorocatechols and chloroguaiacols in contaminated sediments and illustrate the cardinal

  10. Space Operations Center, shuttle interaction study, volume 1

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The implication of using the Shuttle with the SOC, including constraints that the Shuttle places upon the SOC design is studied. The considerations involved in the use of the Shuttle as a part of the SOC concept, and the constraints to the SOC imposed by the Shuttle in its interactions with the SOC, and on the design or technical solutions which allow satisfactory accomplishment of the interactions are identified.

  11. Imalytics Preclinical: Interactive Analysis of Biomedical Volume Data

    PubMed Central

    Gremse, Felix; Stärk, Marius; Ehling, Josef; Menzel, Jan Robert; Lammers, Twan; Kiessling, Fabian

    2016-01-01

    A software tool is presented for interactive segmentation of volumetric medical data sets. To allow interactive processing of large data sets, segmentation operations, and rendering are GPU-accelerated. Special adjustments are provided to overcome GPU-imposed constraints such as limited memory and host-device bandwidth. A general and efficient undo/redo mechanism is implemented using GPU-accelerated compression of the multiclass segmentation state. A broadly applicable set of interactive segmentation operations is provided which can be combined to solve the quantification task of many types of imaging studies. A fully GPU-accelerated ray casting method for multiclass segmentation rendering is implemented which is well-balanced with respect to delay, frame rate, worst-case memory consumption, scalability, and image quality. Performance of segmentation operations and rendering are measured using high-resolution example data sets showing that GPU-acceleration greatly improves the performance. Compared to a reference marching cubes implementation, the rendering was found to be superior with respect to rendering delay and worst-case memory consumption while providing sufficiently high frame rates for interactive visualization and comparable image quality. The fast interactive segmentation operations and the accurate rendering make our tool particularly suitable for efficient analysis of multimodal image data sets which arise in large amounts in preclinical imaging studies. PMID:26909109

  12. Imalytics Preclinical: Interactive Analysis of Biomedical Volume Data.

    PubMed

    Gremse, Felix; Stärk, Marius; Ehling, Josef; Menzel, Jan Robert; Lammers, Twan; Kiessling, Fabian

    2016-01-01

    A software tool is presented for interactive segmentation of volumetric medical data sets. To allow interactive processing of large data sets, segmentation operations, and rendering are GPU-accelerated. Special adjustments are provided to overcome GPU-imposed constraints such as limited memory and host-device bandwidth. A general and efficient undo/redo mechanism is implemented using GPU-accelerated compression of the multiclass segmentation state. A broadly applicable set of interactive segmentation operations is provided which can be combined to solve the quantification task of many types of imaging studies. A fully GPU-accelerated ray casting method for multiclass segmentation rendering is implemented which is well-balanced with respect to delay, frame rate, worst-case memory consumption, scalability, and image quality. Performance of segmentation operations and rendering are measured using high-resolution example data sets showing that GPU-acceleration greatly improves the performance. Compared to a reference marching cubes implementation, the rendering was found to be superior with respect to rendering delay and worst-case memory consumption while providing sufficiently high frame rates for interactive visualization and comparable image quality. The fast interactive segmentation operations and the accurate rendering make our tool particularly suitable for efficient analysis of multimodal image data sets which arise in large amounts in preclinical imaging studies. PMID:26909109

  13. Cation exchange reactions controlling desorption of 90Sr 2+ from coarse-grained contaminated sediments at the Hanford site, Washington

    NASA Astrophysics Data System (ADS)

    McKinley, J. P.; Zachara, J. M.; Smith, S. C.; Liu, C.

    2007-01-01

    Nuclear waste that bore 90Sr 2+ was accidentally leaked into the vadose zone at the Hanford site, and was immobilized at relatively shallow depths in sediments containing little apparent clay or silt-sized components. Sr 2+, 90Sr 2+, Mg 2+, and Ca 2+ was desorbed and total inorganic carbon concentration was monitored during the equilibration of this sediment with varying concentrations of Na +, Ca 2+. A cation exchange model previously developed for similar sediments was applied to these results as a predictor of final solution compositions. The model included binary exchange reactions for the four operant cations and an equilibrium dissolution/precipitation reaction for calcite. The model successfully predicted the desorption data. The contaminated sediment was also examined using digital autoradiography, a sensitive tool for imaging the distribution of radioactivity. The exchanger phase containing 90Sr was found to consist of smectite formed from weathering of mesostasis glass in basaltic lithic fragments. These clasts are a significant component of Hanford formation sands. The relatively small but significant cation exchange capacity of these sediments was thus a consequence of reaction with physically sequestered clays in sediment that contained essentially no fine-grained material. The nature of this exchange component explained the relatively slow (scale of days) evolution of desorption solutions. The experimental and model results indicated that there is little risk of migration of 90Sr 2+ to the water table.

  14. Cation Exchange Reactions Controlling Desorption of 90Sr2+ From Coarse-Grained Contaminated Sediments at the Hanford Site, Washington

    NASA Astrophysics Data System (ADS)

    McKinley, J. P.; Zachara, J. M.; Smith, S. C.; Liu, C.

    2005-12-01

    Nuclear waste that bore 90Sr2+ was accidentally leaked into the vadose zone at the Hanford site, and was immobilized at relatively shallow depths in sediments containing little apparent clay or silt-sized components. We desorbed Sr2+, 90Sr2+, Mg2+, and Ca2+, and monitored total inorganic carbon concentration during the equilibration of this sediment with varying concentrations of Na+ and Ca2+. A cation exchange model previously developed for similar sediments was applied to these results as a predictor of final solution compositions. The model included binary exchange reactions for the four operant cations and an equilibrium dissolution/precipitation reaction for calcite. The model produced an excellent prediction for desorption data. We also examined the contaminated sediment using digital autoradiography, a sensitive tool for imaging the distribution of radioactivity. The exchanger phase containing 90Sr was found to consist of smectite formed from weathering of mesostasis glass in basaltic lithic fragments. These clasts are a significant component of Hanford formation sands. The relatively small but significant cation exchange capacity of these sediments was thus a consequence of reaction with physically sequestered clays in a sediment that contained essentially no fine-grained material. The nature of this exchange component explains the relatively slow (scale of days) evolution of desorption solutions. The experimental and model results indicate that there is little risk of migration of 90Sr2+ to the water table.

  15. Isotopic constraints (210Pb, 228Th) on the sedimentary dynamics of contaminated sediments from a subtropical coastal lagoon (NW Mexico)

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernandez, A.; Hillaire-Marcel, C.; Ghaleb, B.; Paez-Osuna, F.; Soto-Jimenez, M.

    2001-11-01

    Six sediment push-cores were collected at a coastal lagoon system affected by urban and agriculture wastes. The sediments were analyzed for 228Th, 230Th, 232Th, 210Pb, 226Ra, and 137Cs. 137Cs activities were at background level for all samples. The 210Pbtot activities found in the area varied from 0.5 to 4.5 dpm g-1 with 210Pbsup levels ranging between 1.2-1.8 dpm g-1. Cores CHI and EPC showed flat profiles depleted of 210Pbxs, indicating the absence of recent sedimentation. Core CAI shows a flat 210Pbxs profile that seems to be bioturbated. Cores ERC and BRI show chaotic profiles with layers totally depleted in 210Pbxs, likely caused by resuspension triggered by storm conditions. High 228Th/232Th values observed at core ERC suggest that the resuspension event occurred less than 10 years ago. The contaminated sediment of the lagoon are frequently resuspended, re-oxygenated, and therefore the contaminating trace metals will continue to be easily remobilized in the food chain.

  16. Modeling trade-off between PAH toxicity reduction and negative effects of sorbent amendments to contaminated sediments.

    PubMed

    Kupryianchyk, D; Rakowska, M I; Grotenhuis, J T C; Koelmans, A A

    2012-05-01

    Adding activated carbon (AC) to contaminated sediment has been suggested as an effective method for sediment remediation. AC binds chemicals such as polycyclic aromatic hydrocarbons (PAHs), thus reducing the toxicity of the sediment. Negative effects of AC on benthic organisms have also been reported. Here, we present a conceptual model to quantify the trade-off, in terms of biomass changes, between the advantageous PAH toxicity reduction and the negative effects of AC on populations of benthic species. The model describes population growth, incorporates concentration-effect relationships for PAHs in the pore water and for AC, and uses an equilibrium sorption model to estimate PAH pore water concentrations as a function of AC dosage. We calibrated the model using bioassay data and analyzed it by calculating isoclines of zero population growth for two species. For the sediment evaluated here, the results show that AC may safely protect the benthic habitat against considerable sediment PAH concentrations as long as the AC dosage remains below 4%. PMID:22420612

  17. Multicriteria decision analysis to assess options for managing contaminated sediments: Application to Southern Busan Harbor, South Korea.

    PubMed

    Kim, Jongbum; Kim, Suk Hyun; Hong, Gi Hoon; Suedel, Burton C; Clarke, Joan

    2010-01-01

    Many years of untreated effluent discharge from residential areas, a shipyard, a marina, and a large fish market resulted in substantial contamination of bottom sediment in Southern Busan Harbor, South Korea. Contaminants in these sediments include heavy metals and organic compounds. Newly introduced regulations for ocean disposal of dredged material in South Korea pose significant challenges, because the previous practice of offshore disposal of contaminated dredged material was no longer possible after August 2008. The South Korean government has mandated that such sediments be assessed in a way that identifies the most appropriate dredged material management alternative, addressing environmental, social, and cost objectives. An approach using multicriteria decision analysis (MCDA) in combination with comparative risk assessment was used as a systematic and transparent framework for prioritizing several dredged sediment management alternatives. We illustrate how MCDA can recognize the multiple goals of contaminated sediment management. Values used in weighting decision criteria were derived from surveys of stakeholders who were sediment management professionals, business owners, or government decision makers. The results of the analysis showed that land reclamation was the preferred alternative among cement-lock, sediment washing, 3 contained aquatic disposal alternatives (one in combination with a hopper dredge), geotextile tubes, solidification, and land reclamation after solidification treatment. Land reclamation was the preferred alternative, which performed well across all MCDA objectives, because of the availability of a near-shore confined disposal facility within a reasonable distance from the dredging area. PMID:20821674

  18. Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

    USGS Publications Warehouse

    Walters, D.M.; Mills, M.A.; Fritz, K.M.; Raikow, D.F.

    2010-01-01

    We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell Superfund site (Clemson, SC). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upland spiders (Araneidae) along a sediment contamination gradient. Stable isotopes (?13C, ? 15N) indicated that riparian spiders primarily consumed aquatic insects whereas upland spiders consumed terrestrial insects. PCBs in chironomids (mean 1240 ng/g among sites) were 2 orders of magnitude higher than terrestrial insects (15.2 ng/g), similar to differences between riparian (820?2012 ng/g) and upland spiders (30 ng/g). Riparian spider PCBs were positively correlated with sediment concentrations for all taxa (r2 = 0.44?0.87). We calculated spider-based wildlife values (WVs, the minimum spider PCB concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Spider concentrations exceeded WVs for most birds at heavily contaminated sites and were ?14-fold higher for the most sensitive species (chickadee nestlings, Poecile spp.). Spiders are abundant and ubiquitous in riparian habitats, where they depend on aquatic insect prey. These traits, along with the high degree of spatial correlation between spider and sediment concentrations we observed, suggest that they are model indicator species for monitoring contaminated sediment sites and assessing risks associated with contaminant flux into terrestrial ecosystems. ?? This article not subject to U.S. Copyright. Published 2009 by the American Chemical Society.

  19. Assessing the Effects of Bioturbation on Metal Bioavailability in Contaminated Sediments by Diffusive Gradients in Thin Films (DGT).

    PubMed

    Amato, Elvio D; Simpson, Stuart L; Remaili, Timothy M; Spadaro, David A; Jarolimek, Chad V; Jolley, Dianne F

    2016-03-15

    The burrowing and feeding activities of benthic organisms can alter metal speciation in sediments and affect an organisms' exposure to metals. Recently, the performance of the in situ technique of diffusive gradients in thin films (DGT) for predicting metal bioavailability has been investigated in response to the increasing demand of considering contaminant bioavailability in sediment quality assessments. In this study, we test the ability of the DGT technique for predicting the metal bioavailability in clean and contaminated sediments that are being subjected to varying degrees of sediments disturbance: low bioturbation (bivalve Tellina deltoidalis alone) and high bioturbation (bivalve and actively burrowing amphipod, Victoriopisa australiensis). Significant release of DGT-labile Cd, Ni, Pb, and Zn, but lower Cu and Fe, occurred in the pore and overlying waters of sediments exposed to high bioturbation conditions, resulting in higher bioaccumulation of zinc in bivalves. Strong relationships were found between bioaccumulation of Pb and Zn and time-integrated DGT-metal fluxes, whereas poor relationships were obtained using total or dilute-acid extractable metal concentrations. This results demonstrate that DGT is a useful tool for assessing metal bioavailability in sediments and can provide useful predictions of metal bioavailable to benthic organisms in dynamic sediment environments. PMID:26848961

  20. Effects of activated carbon ageing in three PCB contaminated sediments: Sorption efficiency and secondary effects on Lumbriculus variegatus.

    PubMed

    Nybom, Inna; Waissi-Leinonen, Greta; Mäenpää, Kimmo; Leppänen, Matti T; Kukkonen, Jussi V K; Werner, David; Akkanen, Jarkko

    2015-11-15

    The sorption efficiency and possible secondary effects of activated carbon (AC) (ø 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive samplers. However, dose related secondary effects of AC on egestion rate and biomass were observed (applied doses 0.25% and 2.5% sediment dry weight). The sorption capacity and secondary effects remained similar when the experiments were repeated after three years of AC-sediment contact time. Further, transmission electron microscopy (TEM) samples revealed morphological changes in the L. variegatus gut wall microvilli layer. Sediment properties affected both sorption efficiency and secondary effects, but 2.5% AC addition had significant effects regardless of the sediment. In, conclusion, AC is an efficient and stable sorbent to decrease the bioavailability of PCBs. However, sediment dwelling organisms, such as Oligochaete worms in this study, may be sensitive to the carbon amendments. The secondary effects and possible morphological changes in benthic organisms should not be overlooked as in many cases they form the basis of the aquatic food webs. PMID:26364225

  1. Potential use of acetylcholinesterase, glutathione-S-transferase and metallothionein for assessment of contaminated sediment in tropical chironomid, Chironomus javanus.

    PubMed

    Somparn, A; Iwai, C B; Noller, B

    2015-11-01

    Heavy metals and organophosphorus insecticide is known to act as disruptors for the enzyme system, leading to physiologic disorders. The present study was conducted to investigate the potential use of these enzymes as biomarkers in assessment of contaminated sediments on tropical chironomid species. Acetylcholinesterase (AChE), glutathione-S-transferase (GST) and metallothionein (MT) activity was measured in the fourth-instar chironomid larvae, Chironomus javanus, Kieffer, after either 48-hr or 96-hr exposure to organophosphorus insecticide, chlorpyrifos (0.01- 0.25 mg kg(-1)) or heavy metal cadmium (0.1-25 mg kg(-1)). Exposure to chlorpyrifos (0.01 mg kg(-1)) at 48 and 96 hr significantly of AChE activity (64.2%-85.9%) and induced GST activity (33.9-63.8%) when compared with control (P < 0.05). Moreover, exposure to cadmium (0.1 mg kg(-1)) at 48 and 96 hr also showed significant increas GST activity (11.7-40%) and MT level (9.0%-70.5%) when compared with control (P < 0.05). The results indicated the impact of enzyme activity on chlorpyrifos and cadmium contamination. Activity of AChE, GST and MT could serve as potential biomarkers for assessment and biomonitoring the effects of insecticide and heavy metal contamination in tropical aquatic ecosystems. PMID:26688973

  2. Kinetics of uranium(VI) desorption from contaminated sediments: effect of geochemical conditions and model evaluation.

    PubMed

    Liu, Chongxuan; Shi, Zhenqing; Zachara, John M

    2009-09-01

    Stirred-flow cell experiments were performed to investigate the kinetics of uranyl [U(VI)] desorption from a contaminated sedimentcollected from the Hanford 300 Area at the U.S. Department of Energy Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(Vl) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the solutions and sediment The solution chemical composition that led to a larger disequilibrium between adsorbed U(VI) and equilibrium adsorption state yielded a faster desorption rate. The experimental results were used to evaluate a multirate, surface complexation model (SCM) that has been proposed to describe U(VI) desorption kinetics in the Hanford sedimentthat contained complex adsorbed U(VI) in mass transfer limited domains (Lui et al. Water Resour. Res. 2008, 44, W08413). The model was modified and supplemented by including multirate, ion exchange reactions to describe the geochemical interactions between the solutions and sediment With the same setof model parameters, the modified model reasonably well described the evolution of major ions and the rates of U(VI) desorption under variable geochemical and flow conditions, implying that the multirate SCM is an effective way to describe U(VI) desorption kinetics in subsurface sediments. PMID:19764217

  3. Interaction between Personnelmen and Enlisted Men: A Study. Volume 1.

    ERIC Educational Resources Information Center

    Best, H. L.; Skinner, W. H.

    This study reports on the effects on Navy image resulting from the interaction between personnelmen (PNs) and their client enlisted men. A series of interviews and responses to a sort questionnaire provided data on the agreements and disagreements between the groups. A major disagreement was investigated between the young enlisted man who…

  4. Effects of Oil-Contaminated Sediments on Submerged Vegetation: An Experimental Assessment of Ruppia maritima

    PubMed Central

    Martin, Charles W.; Hollis, Lauris O.; Turner, R. Eugene

    2015-01-01

    Oil spills threaten the productivity of ecosystems through the degradation of coastal flora and the ecosystem services these plants provide. While lab and field investigations have quantified the response of numerous species of emergent vegetation to oil, the effects on submerged vegetation remain uncertain. Here, we discuss the implications of oil exposure for Ruppia maritima, one of the most common species of submerged vegetation found in the region affected by the recent Deepwater Horizon oil spill. We grew R. maritima in a range of manipulated sediment oil concentrations: 0, 0.26, 0.53, and 1.05 mL oil /L tank volume, and tracked changes in growth (wet weight and shoot density/length), reproductive activity (inflorescence and seed production), root characteristics (mass, length, diameter, and area), and uprooting force of plants. While no statistical differences were detected in growth, plants exhibited significant changes to reproductive output, root morphology, and uprooting force. We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations. In addition, the roots growing in the high oil were shorter and wider. Plants in medium and high oil required less force to uproot. A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil. Given the importance of sexual reproduction for these plants, oil contamination may have substantial population-level effects. Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima. PMID:26430971

  5. Effects of Oil-Contaminated Sediments on Submerged Vegetation: An Experimental Assessment of Ruppia maritima.

    PubMed

    Martin, Charles W; Hollis, Lauris O; Turner, R Eugene

    2015-01-01

    Oil spills threaten the productivity of ecosystems through the degradation of coastal flora and the ecosystem services these plants provide. While lab and field investigations have quantified the response of numerous species of emergent vegetation to oil, the effects on submerged vegetation remain uncertain. Here, we discuss the implications of oil exposure for Ruppia maritima, one of the most common species of submerged vegetation found in the region affected by the recent Deepwater Horizon oil spill. We grew R. maritima in a range of manipulated sediment oil concentrations: 0, 0.26, 0.53, and 1.05 mL oil /L tank volume, and tracked changes in growth (wet weight and shoot density/length), reproductive activity (inflorescence and seed production), root characteristics (mass, length, diameter, and area), and uprooting force of plants. While no statistical differences were detected in growth, plants exhibited significant changes to reproductive output, root morphology, and uprooting force. We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations. In addition, the roots growing in the high oil were shorter and wider. Plants in medium and high oil required less force to uproot. A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil. Given the importance of sexual reproduction for these plants, oil contamination may have substantial population-level effects. Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima. PMID:26430971

  6. Assessing organic contaminant fluxes from contaminated sediments following dam removal in an urbanized river.

    PubMed

    Cantwell, Mark G; Perron, Monique M; Sullivan, Julia C; Katz, David R; Burgess, Robert M; King, John

    2014-08-01

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in the water column prior to and following removal of a small, low-head dam in the Pawtuxet River, an urbanized river located in Cranston, RI, USA. During the study, concentrations of particulate and dissolved PAHs ranged from 21.5 to 103 μg/g and from 68 to 164 ng/L, respectively. Overall, temporal trends of PAHs showed no increases in either dissolved or particulate phases following removal of the dam. Dissolved concentrations of PCBs were very low, remaining below 1.72 ng/L at all sites. Particulate PCB concentrations across sites and time showed slightly greater variability, ranging from 80 to 469 ng/g, but with no indication that dam removal influenced any increases. Particulate PAHs and PCBs were sampled continuously at the site located below the dam and did not show sustained increases in concentration resulting from dam removal. The employment of passive sampling technology and sediment traps was highly effective in monitoring the concentrations and flux of contaminants moving through the river system. Variations in river flow had no effect on the concentration of contaminants in the dissolved or particulate phases, but did influence the flux rate of contaminants exiting the river. Overall, dam removal did not cause measurable sediment disturbance or increase the concentration or fluxes of dissolved or particulate PAHs and PCBs. This is due in large part to low volumes of impounded sediment residing above the dam and highly armored sediments in the river channel, which limited erosion. Results from this study will be used to improve methods and approaches that assess the short- and long-term impacts ecological restoration activities such as

  7. Composition, distribution, and hydrologic effects of contaminated sediments resulting from the discharge of gold milling wastes to Whitewood Creek at Lead and Deadwood, South Dakota

    USGS Publications Warehouse

    Goddard, K.E.

    1989-01-01

    The Whitewood Creek-Belle Fourche-Cheyenne River stream system in western South Dakota has been extensively contaminated by the discharge to Whitewood Creek of about 100 million tons of mill tailings from gold-mining operations. The resulting contaminated sediments contain unusually large concentrations of arsenic, as much as 11,000 micrograms/g, derived from the mineral arsenopyrite, as well as potentially toxic constituents derived from the ore-body minerals or from the milling processes. Because of the anomalous arsenic concentrations associated with the contamination, arsenic was used as an indicator for a geochemically based, random, sediment-sampling program. Arsenic concentrations in shallow, contaminated sediments along the flood plains of the streams were from 1 to 3 orders of magnitude larger than arsenic concentrations in uncontaminated sediments in about 75% of the flood plains of Whitewood Creek and the Belle Fourche River. Appreciable surface-water contamination resulting from the contaminated sediments is confined to Whitewood Creek and a reach of the Belle Fourche River downstream from the mouth of Whitewood Creek. In Whitewood Creek , dissolved-arsenic concentrations vary from about 20 to 80 microgram/L during the year in response to variations in groundwater inflow and dilution, whereas total-recoverable-arsenic concentrations vary from about 20 to 8 ,000 micrograms/L during short periods in response to rapid changes in suspended-sediment concentration. Contamination of the alluvial aquifer along the stream system is limited to areas in direct contact with large deposits of contaminated sediments. Within the aquifer, arsenic concentrations are thought to be controlled by sorption-desorption on metallic hydroxides. (USGS)

  8. Vortex/boundary-layer interactions: Data report, volume 1

    NASA Technical Reports Server (NTRS)

    Cutler, A. D.; Bradshaw, P.

    1987-01-01

    This report summarizes the work done under NASA Grant NAGw-581, Vortex/Boundary Layer Interactions. The experimental methods are discussed in detail and numerical results are presented, but are not fully interpreted. This report should be useful to anyone who wishes to make further use of the data (available on floppy disc or magnetic tape) for the development of turbulence models or the validation of predictive methods. Journal papers are in course of preparation.

  9. The use of coarse, separable, condensed-phase organic carbon particles to characterize desorption resistance of polycyclic aromatic hydrocarbons in contaminated sediments

    SciTech Connect

    Chai, Y.Z.; Kochetkov, A.; Reible, D.D.

    2007-07-15

    Physical separations were employed to characterize the source of desorption-resistant behavior for polycyclic aromatic hydrocarbons (PAHs) in laboratory- and field-contaminated sediments. Size and density separation of laboratory-contaminated sediments did not effectively separate the amorphous-phase (volatile) and condensed-phase (nonvolatile) organic carbon as measured by thermal oxidation at 375 {sup o}C. These separations also did not result in sediment fractions with significantly different desorption characteristics as measured by apparent partition coefficients. Coarse particles from a field-contaminated sediment from Utica Harbor (UH; Utica, NY, USA), however, could be directly separated into sandy fractions and organic fractions that were composed of woody organic matter, charcoal or charred vegetative matter, and coal-like and coal-cinder particles. Chemical analysis showed that coal-like (glassy, nonporous) and coal-cinder (porous, sintered) particles exhibited very high PAH concentrations and high apparent partition coefficients. These particles also exhibited significantly higher condensed-phase (nonvolatile) organic carbon contents as defined by thermal oxidation at 375{sup o}C. The apparent partition coefficients of PAHs in the coal-cinder particles were a good indication of the apparent partition coefficients in the desorption-resistant fraction of UH sediment, indicating that the coarse particles provided a reasonable characterization of the desorption-resistance phenomena in these sediments even though the coarse fractions represented less than 25% of the organic carbon in the whole sediment.

  10. Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

    SciTech Connect

    Gao, Yenan; Dong, Lifang Zhao, Longhu; Wang, Yongjie; Pan, Yuyang; Li, Ben

    2014-10-15

    The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

  11. Implications of Glacier Volume Change for Ice-Ocean Interactions

    NASA Astrophysics Data System (ADS)

    Hood, E. W.; O'Neel, S.; Fellman, J.; Bidlack, A.; Arendt, A. A.; Arimitsu, M.; Spencer, R. G.

    2015-12-01

    Changes in climate are forcing complex glaciological responses that can be transmitted to downstream ecosystems via glacier runoff. Along the Gulf of Alaska, rates of glacier mass loss are among the highest measured on Earth. Changes in glacier volume in this region are altering the amount of glacier runoff delivered to the coastal ocean. Moreover, shifts in glacier extent are changing the location of the ice-ocean interface and, in cases where tidewater glaciers become grounded, fundamentally altering circulation in glacierized fjords. The runoff from glacier ecosystems is unique in terms of its physical and chemical properties when compared to runoff from non-glacial ecosystems. For example, the silt and chemical constituents in glacier discharge alter light penetration and the nutrient regime in near-shore marine ecosystems, which, in turn, influence levels of marine primary productivity. Future changes in the magnitude, timing, and location of glacier runoff have important implications for biogeochemical and ecological processes in glacially-dominated fjords and estuaries. This talk will highlight research from glacierized watersheds and fjords to synthesize what is known about the physical, chemical, and biological linkages that characterize icefield-ocean ecosystems along the Gulf of Alaska.

  12. Recent advances in the use of estuarine meiobenthos to assess contaminated sediment effects in multi-species whole sediment microcosms

    SciTech Connect

    Chandler, G.T.; Coull, B.C.; Schizas, N.V.; Donelan, T.L.

    1995-12-31

    Many marine meiobenthic taxa (i.e. invertebrates passing a 1-mm sieve but retaining on a 0.063 mm sieve) are ideal for ``whole-sediment`` and porewater bioassay of sedimented pollutants. Annual production of meiobenthos is 5--10 times that of the more commonly studied macrobenthos, and > 95% of all meiobenthos live in the oxic zone of muddy sediments at densities of 4--12 million per M{sup 2}. Most spend their entire lifecycles, burrowing freely and feeding on/within the sediment:porewater matrix, many taxa undergo 10--14 generations per year, most larval/juvenile stages are benthic, and many have easily quantifiable reproductive output. Furthermore, many meiobenthic taxa can be cultured indefinitely over multiple life-cycles within simple sediment microcosms consisting of sealed whole-sediment cores collected intact from intertidal mudflats. The authors describe several recent technical developments exploiting meiofaunal sediment culture for rapid contaminated sediment bioassays of toxicant effects on survival, reproduction and population growth of meiobenthic taxa in whole-sediment microcosms. Currently meiobenthic copepods, nematodes, foraminifers and polychaetes are being continuously cultured to study these parameters under exposure to model sediment-associated toxicants (e.g. cadmium). Bioassays are run for 21-d under flowing seawater. With this approach, fertile benthic copepods (e.g. Amphiascus tenuiremis) can be added to core microcosms to assess survival and growth of a fixed population cohort. All other meiobenthic taxa are enumerated relative to controls and evaluated for toxicant effects on higher order community-level endpoints. This approach exploits meiobenthos` high abundance and rapid reproductive rates to yield on a micro scale better endpoints than much larger sediment mesocosms targeted at macrofaunal endpoints.

  13. Fluorescent aromatic hydrocarbons in bile as a biomarker of exposure of brown bullheads (Ameiurus nebulosus) to contaminated sediments

    SciTech Connect

    Leadly, T.A.; Haffner, G.D.; Arcand-Hoy, L.D.; Metcalfe, C.D.

    1999-04-01

    Analysis of fluorescent aromatic compounds (FACs) in the bile of fish has been widely used as a biomarker of exposure to polynuclear aromatic hydrocarbon (PAH) contamination. However, bile FAC data for feral fish populations are typically highly variable, and in a few cases, elevation of FACs has not been observed in fish from contaminated areas. In this study, the bile FACs and hepatic ethoxyresorufin-O-deethylase activity in brown bullheads (Ameiurus nebulosus) exposed in the laboratory to contaminated sediments from Hamilton Harbour, Ontario, Canada, increased by 173-fold within 72 h of initial exposure and rapidly declined thereafter. In bullheads caged in the contaminated Trenton Channel area of the Detroit River, bile FACs also increased rapidly within 4 d of initial exposure to mean levels >3,000 ng of benzo[a]pyrene equivalents per milliliter of bile. Surprisingly, there was no difference in the mean-levels of bile FACs in fish caged above the sediment versus fish caged in direct contact with the sediment, indicating that water may be the major vector for uptake of PAHs. The lower bile FACs in bullheads caged in other regions of the Detroit River were consistent with the lower concentrations of PAHs in the sediments from these areas. These data indicate that bile FAC levels are a biomarker of recent exposure to aromatic hydrocarbons in sediments. However, FAC data were highly variable even in these studies, in which fish were relatively homogenous in size, feeding status, and exposure history. Therefore, Even higher variability in bile FAC data are expected in biomarker studies as a result of differences in reproductive status, size, diet, and mobility of the fish.

  14. Relaxed image foresting transforms for interactive volume image segmentation

    NASA Astrophysics Data System (ADS)

    Malmberg, Filip; Nyström, Ingela; Mehnert, Andrew; Engstrom, Craig; Bengtsson, Ewert

    2010-03-01

    The Image Foresting Transform (IFT) is a framework for image partitioning, commonly used for interactive segmentation. Given an image where a subset of the image elements (seed-points) have been assigned correct segmentation labels, the IFT completes the labeling by computing minimal cost paths from all image elements to the seed-points. Each image element is then given the same label as the closest seed-point. Here, we propose the relaxed IFT (RIFT). This modified version of the IFT features an additional parameter to control the smoothness of the segmentation boundary. The RIFT yields more intuitive segmentation results in the presence of noise and weak edges, while maintaining a low computational complexity. We show an application of the method to the refinement of manual segmentations of a thoracolumbar muscle in magnetic resonance images. The performed study shows that the refined segmentations are qualitatively similar to the manual segmentations, while intra-user variations are reduced by more than 50%.

  15. Early adversity and combat exposure interact to influence anterior cingulate cortex volume in combat veterans☆

    PubMed Central

    Woodward, Steven H.; Kuo, Janice R.; Schaer, Marie; Kaloupek, Danny G.; Eliez, Stephan

    2013-01-01

    Objective Childhood and combat trauma have been observed to interact to influence amygdala volume in a sample of U.S. military veterans with and without PTSD. This interaction was assessed in a second, functionally-related fear system component, the pregenual and dorsal anterior cingulate cortex, using the same sample and modeling approach. Method Anterior cingulate cortical tissues (gray + white matter) were manually-delineated in 1.5 T MR images in 87 U.S. military veterans of the Vietnam and Persian Gulf wars. Hierarchical multiple regression modeling was used to assess associations between anterior cingulate volume and the following predictors, trauma prior to age 13, combat exposure, the interaction of early trauma and combat exposure, and PTSD diagnosis. Results As previously observed in the amygdala, unique variance in anterior cingulate cortical volume was associated with both the diagnosis of PTSD and with the interaction of childhood and combat trauma. The pattern of the latter interaction indicated that veterans with childhood trauma exhibited a significant inverse linear relationship between combat trauma and anterior cingulate volume while those without childhood trauma did not. Such associations were not observed in hippocampal or total cerebral tissue volumes. Conclusions In the dorsal anterior cingulate cortex, as in the amygdala, early trauma may confer excess sensitivity to later combat trauma. PMID:24179818

  16. Excluded-volume interaction induced stiffness of comb polymer with densely grafted side-chains

    NASA Astrophysics Data System (ADS)

    Qiu, Feng

    2014-03-01

    Excluded-volume interaction has been widely recognized to cause expansion of polymer chain at large length scale. However, its effect on chain conformations at small length scale has been studied to less extent. Here we consider a comb polymer with its backbone densely grafted by side-chains as a model system. The method analogue to solving the electrostatic persistence length problem for either rigid or flexible polyelectrolytes is employed. For comb polymers with rigid backbone near the rod limit, the excluded-volume interaction induced persistence length scales linearly with the volume of the side-chain. While for flexible backbone, the persistence length depends on the side-chain volume more weakly. Field theoretic method that is relevant to address this problem is also explored and discussed. Work supported by NSFC.

  17. Flow interaction experiment. Volume 2: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  18. Flow interaction experiment. Volume 1: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  19. The associations of depression and hypertension with brain volumes: Independent or interactive?

    PubMed Central

    Meurs, Maaike; Groenewold, Nynke A.; Roest, Annelieke M.; van der Wee, Nic J.A.; Veltman, Dick J.; van Tol, Marie-José; de Jonge, Peter

    2015-01-01

    Independent studies on major depressive disorder (MDD) and hypertension, suggest overlapping abnormalities in brain regions associated with emotional and autonomic processing. However, the unique and interactive effects of MDD and hypertension have never been studied in a single sample. Brain volume in these areas may be an explanatory link in the comorbidity between MDD and hypertension. Voxel-based morphometry was used to test for main effects of MDD (N = 152) and hypertension (N = 82) and their interactions on gray and white matter volumes. Voxel-wise results are reported at p < .05 FWE corrected for the spatial extent of the whole brain and a-priori regions of interest (ROIs: hippocampus, anterior cingulate cortex (ACC) and inferior frontal gyrus (IFG)). In addition, analyses on the extracted total volumes of our ROIs were performed. Interactive effects in the mid-cingulate cortex (MCC) (pFWE = .01), cerebellum (pFWE = .01) and in the ACC total ROI volume (p = .02) were found. MDD in the presence, but not in the absence of hypertension was associated with lower volumes in the ACC and MCC, and with a trend towards larger gray matter volume in the cerebellum. No associations with white matter volumes were observed. Results suggest that the combination of MDD and hypertension has a unique effect on brain volumes in areas implicated in the regulation of emotional and autonomic functions. Brain volume in these regulatory areas may be an explanatory link in the comorbidity between hypertension and MDD. PMID:26106530

  20. Evidence of Chlorobenzene Natural Attenuation in Contaminated Sediments Using Compound Specific Isotope Analysis and High Resolution Pore Water Sampling

    NASA Astrophysics Data System (ADS)

    Passeport, E.; Landis, R.; Lacrampe Couloume, G.; Lutz, E. J.; Mack, E. E.; West, K.; Sherwood Lollar, B.

    2014-12-01

    Contaminated sediments can represent a significant risk for ecosystems and hinder drinking water production if contaminants discharge to surface and ground water. Understanding of contaminant fate and the potential for natural attenuation can help protect aquatic resources. In this study, the fate of chlorobenzene (MCB) and benzene was investigated in a contaminated canal sediment field site located in New Jersey, USA. Compound Specific Isotope Analysis (CSIA) was applied to sediment pore water samples collected with a peeper at high spatial resolution (3 cm) across the sediment - surface water interface (SWI). Samples were collected at three locations in canal sediments, all of which exhibited reducing redox conditions. The largest concentrations were observed in the bottommost portions of the sediment profile, with concentrations ranging from 300 to 2000 µg/L for MCB, and 16 to 180 µg/L for benzene. Conversely, concentrations were below detection limit in the surface water and in the top 6 cm of the sediment. In the zones of highest MCB concentrations, the δ13C values were -26.4 (location C) and -21.9 ‰ (location F), and became progressively more enriched in 13C while concentrations decreased, reaching -23.9 (at 12 cm below the SWI, location C) and -18.4 ‰ (at 16.5 cm below SWI, location F). Benzene was only detected in the bottom 6 cm of the sediment profiles. Benzene δ13C values were -27 (bottommost, i.e., 24 cm deep) to -29.7 ‰ (18 cm deep), in location C. Such significant isotopic enrichments in 13C (2.5 to 3.5 ‰) correlated with MCB and benzene concentration decrease are suggestive of in situ biodegradation. In addition, benzene δ13C values were systematically more depleted in 13C than MCB, suggesting that benzene found in these zones was likely produced from MCB via reductive dechlorination. This study combined for the first time CSIA with high spatial sampling resolution in surface water sediments. This setup enabled not only detection of

  1. Effects of bioaugmentation on sorption and desorption of benzene, 1,3,5-trimethylbenzene and naphthalene in freshly-spiked and historically-contaminated sediments.

    PubMed

    Li, YueHua; Chen, Liang; Liu, YuLong; Liu, Fei; Fallgren, Paul H; Jin, Song

    2016-11-01

    This work investigated the frequently observed "rebounds" of contaminants of concern in groundwater systems. Specifically, influences of bioaugmented microorganisms on the sorption and desorption of representative petroleum constituents [benzene, 1,3,5-trimethylbenzene and naphthalene (BTN)] were studied in freshly-spiked and historically-contaminated sediments. Capable microorganisms were enriched and supplemented to contaminated sediments to enhance biodegradation of petroleum hydrocarbons. In freshly-spiked sediments, when petroleum-degrading microorganisms were added, concentrations of dissolved petroleum constituents appeared to increase initially, and 12.4, 14.0 and 20.0 mg/kg of benzene, 1,3,5-trimethylbenzene and naphthalene, respectively desorbed from the sediments into the water phase. In the historically-contaminated sediments, the augmentation of petroleum-degrading microorganisms led to the desorption of 0.023-0.059, 0009-0.016, and 1.731-2.763 mg/L of previously sequestrated BTN into the water phase, and also triggered the desorption of 0.051-0.223, -0.133-2.630, and 2.324-1.200 mg/kg of previously sequestrated BTN as the methanol extraction quantity. The mechanisms of the enhanced desorption at the presence of microbes remain to be determined; however, we presumed that microbially produced constituents such as biosurfactants and cell mass could have attributed to the partition of petroleum compounds from the sediments. Findings from this study may partially explain "rebounds" of certain petroleum constituents into the groundwater during in situ bioremediation practice, although such immediate rebounds sometimes are weak, and the desorbed constituents can be eventually biodegraded under proper biogeochemical conditions. PMID:27474910

  2. Toxicity of smelter slag-contaminated sediments from Upper Lake Roosevelt and associated metals to early life stage White Sturgeon (Acipenser transmontanus Richardson, 1836)

    USGS Publications Warehouse

    Little, E.E.; Calfee, R.D.; Linder, G.

    2014-01-01

    The toxicity of five smelter slag-contaminated sediments from the upper Columbia River and metals associated with those slags (cadmium, copper, zinc) was evaluated in 96-h exposures of White Sturgeon (Acipenser transmontanus Richardson, 1836) at 8 and 30 days post-hatch. Leachates prepared from slag-contaminated sediments were evaluated for toxicity. Leachates yielded a maximum aqueous copper concentration of 11.8 μg L−1 observed in sediment collected at Dead Man's Eddy (DME), the sampling site nearest the smelter. All leachates were nonlethal to sturgeon that were 8 day post-hatch (dph), but leachates from three of the five sediments were toxic to fish that were 30 dph, suggesting that the latter life stage is highly vulnerable to metals exposure. Fish maintained consistent and prolonged contact with sediments and did not avoid contaminated sediments when provided a choice between contaminated and uncontaminated sediments. White Sturgeon also failed to avoid aqueous copper (1.5–20 μg L−1). In water-only 96-h exposures of 35 dph sturgeon with the three metals, similar toxicity was observed during exposure to water spiked with copper alone and in combination with cadmium and zinc. Cadmium ranging from 3.2 to 41 μg L−1 or zinc ranging from 21 to 275 μg L−1 was not lethal, but induced adverse behavioral changes including a loss of equilibrium. These results suggest that metals associated with smelter slags may pose an increased exposure risk to early life stage sturgeon if fish occupy areas contaminated by slags.

  3. Coil–globule transition of a polymer involved in excluded-volume interactions with macromolecules

    SciTech Connect

    Odagiri, Kenta; Seki, Kazuhiko

    2015-10-07

    Polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies. The transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy/entropy balance. Previously, this transition was theoretically studied by taking into account the excluded-volume interaction between monomers of a polymer chain using the partition function. For binary mixtures of a long polymer and short polymers, the coil-globule transition can be induced by changing the concentration of the shorter polymers. Here, we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded-volume effect of short polymers. The coil-globule transition is studied as a function of the concentration of mixed polymers by systematically varying Flory’s χ-parameters. We show that the transition is caused by the interplay between the excluded-volume interaction and the dispersion state of short polymers in the solvent. We also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined.

  4. Effects of Amendments on Growth and Uptake of Cd and Zn by Wetland Plants, Typha angustifolia and Colocasia esculenta from Contaminated Sediments.

    PubMed

    Chayapan, P; Kruatrachue, M; Meetam, M; Pokethitiyook, P

    2015-01-01

    A pot study was conducted to compare the effects of amendments (CaHPO4 and cow manure) on growth and uptake of Cd and Zn from contaminated sediments by two wetland plant species, Typha angustifolia and Colocasia esculenta. Contaminated sediments (Cd 33.2 mg kg(-1) and Zn 363 mg kg(-1)) were collected from Mae Tao basin, Mae Sot district, Tak province, Thailand. The experiment consisted of 4 treatments: control (uncontaminated sediment), Cd/Zn, Cd/Zn + 5% CaHPO4, and Cd/Zn + 10% cow manure. Plants were grown for 3 months in the greenhouse. The addition of CaHPO4 resulted in the highest relative growth rate (RGR) and highest Cd accumulation in both T. angustifolia and C. esculenta while the lowest RGR was found in C. esculenta grown in the cow manure treatment. Both plant species had higher concentrations of metals (Cd, Zn) in their belowground parts. None of the amendments affected Zn accumulation. C. esculenta exhibited the highest uptake of both Cd and Zn. The results clearly demonstrated the phytoremediation potential of C. esculenta and the enhancement of this potential by CaHPO4 amendment. PMID:25831275

  5. Developmentally Sensitive Interaction Effects of Genes and the Social Environment on Total and Subcortical Brain Volumes

    PubMed Central

    Arias Vásquez, Alejandro; Franke, Barbara; Hoekstra, Pieter J.; Heslenfeld, Dirk J.; Oosterlaan, Jaap; Faraone, Stephen V.

    2016-01-01

    Smaller total brain and subcortical volumes have been linked to psychopathology including attention-deficit/hyperactivity disorder (ADHD). Identifying mechanisms underlying these alterations, therefore, is of great importance. We investigated the role of gene-environment interactions (GxE) in interindividual variability of total gray matter (GM), caudate, and putamen volumes. Brain volumes were derived from structural magnetic resonance imaging scans in participants with (N = 312) and without ADHD (N = 437) from N = 402 families (age M = 17.00, SD = 3.60). GxE effects between DAT1, 5-HTT, and DRD4 and social environments (maternal expressed warmth and criticism; positive and deviant peer affiliation) as well as the possible moderating effect of age were examined using linear mixed modeling. We also tested whether findings depended on ADHD severity. Deviant peer affiliation was associated with lower caudate volume. Participants with low deviant peer affiliations had larger total GM volumes with increasing age. Likewise, developmentally sensitive GxE effects were found on total GM and putamen volume. For total GM, differential age effects were found for DAT1 9-repeat and HTTLPR L/L genotypes, depending on the amount of positive peer affiliation. For putamen volume, DRD4 7-repeat carriers and DAT1 10/10 homozygotes showed opposite age relations depending on positive peer affiliation and maternal criticism, respectively. All results were independent of ADHD severity. The presence of differential age-dependent GxE effects might explain the diverse and sometimes opposing results of environmental and genetic effects on brain volumes observed so far. PMID:27218681

  6. Role of material loss and mode volume of plasmonic nanocavities for strong plasmon-exciton interactions.

    PubMed

    Yang, Zhong-Jian; Antosiewicz, Tomasz J; Shegai, Timur

    2016-09-01

    We investigate the role of material loss and mode volume of plasmonic nanostructures on strong plasmon-exciton coupling. We find that the field enhancement, and therefore loss, is not important for the magnitude of the Rabi splitting as such, but instead it is determined by the mode volume. Nevertheless, for reaching true strong coupling condition, that is, coupling greater than any dissipation, it is important to compromise losses. We also show that using such popular geometries as a dimer of two spheres or bow-tie nanoantennas, does not allow compressing the mode volume much in comparison to a single nanoparticle case, except for very narrow gaps, but rather it allows for efficient extraction of the mode out of the metal thus making it more accessible for excitons to interact with. Even more efficient mode extraction is achieved when high refractive index dielectric is placed in the gap. Our findings may find practical use for quantum plasmonics applications. PMID:27607644

  7. Fluid structure interaction solver coupled with volume of fluid method for two-phase flow simulations

    NASA Astrophysics Data System (ADS)

    Cerroni, D.; Fancellu, L.; Manservisi, S.; Menghini, F.

    2016-06-01

    In this work we propose to study the behavior of a solid elastic object that interacts with a multiphase flow. Fluid structure interaction and multiphase problems are of great interest in engineering and science because of many potential applications. The study of this interaction by coupling a fluid structure interaction (FSI) solver with a multiphase problem could open a large range of possibilities in the investigation of realistic problems. We use a FSI solver based on a monolithic approach, while the two-phase interface advection and reconstruction is computed in the framework of a Volume of Fluid method which is one of the more popular algorithms for two-phase flow problems. The coupling between the FSI and VOF algorithm is efficiently handled with the use of MEDMEM libraries implemented in the computational platform Salome. The numerical results of a dam break problem over a deformable solid are reported in order to show the robustness and stability of this numerical approach.

  8. Propulsion and airframe aerodynamic interactions of supersonic V/STOL configurations. Volume 4: Summary

    NASA Technical Reports Server (NTRS)

    Zilz, D. E.; Wallace, H. W.; Hiley, P. E.

    1985-01-01

    A wind tunnel model of a supersonic V/STOL fighter configuration has been tested to measure the aerodynamic interaction effects which can result from geometrically close-coupled propulsion system/airframe components. The approach was to configure the model to represent two different test techniques. One was a conventional test technique composed of two test modes. In the Flow-Through mode, absolute configuration aerodynamics are measured, including inlet/airframe interactions. In the Jet-Effects mode, incremental nozzle/airframe interactions are measured. The other test technique is a propulsion simulator approach, where a sub-scale, externally powered engine is mounted in the model. This allows proper measurement of inlet/airframe and nozzle/airframe interactions simultaneously. This is Volume 4 of 4: Final Report- Summary.

  9. Electrostatic, elastic and hydration-dependent interactions in dermis influencing volume exclusion and macromolecular transport.

    PubMed

    Øien, Alf H; Wiig, Helge

    2016-07-01

    Interstitial exclusion refers to the limitation of space available for plasma proteins and other macromolecules based on collagen and negatively charged glycosaminoglycans (GAGs) in the interstitial space. It is of particular importance to interstitial fluid and plasma volume regulation. Here we present a novel mechanical and mathematical model of the dynamic interactions of structural elements within the interstitium of the dermis at the microscopic level that may explain volume exclusion of charged and neutral macroparticles. At this level, the interstitium is considered to consist of elements called extracellular matrix (ECM) cells, again containing two main interacting structural components on a fluid background including anions and cations setting up osmotic forces: one smaller GAG component, having an intrinsic expansive electric force, and one bigger collagen component, having an intrinsic elastic force. Because of size differences, the GAG component interacts with a fraction of the collagen component only at normal hydration. This fraction, however, increases with rising hydration as a consequence of the modeled form of the interaction force between the GAGs and collagen. Collagen is locally displaced at variable degrees as hydration changes. Two models of GAGs are considered, having largely different geometries which demands different, but related, forms of GAG-collagen interaction forces. The effects of variable fixed charges on GAGs and of GAG density in tissue are evaluated taking into account observed volume exclusion properties of charged macromolecules as a function of tissue hydration. The presented models may improve our biophysical understanding of acting forces influencing tissue fluid dynamics. Such knowledge is significant when evaluating the transport of electrically charged and neutral macromolecules into and through the interstitium, and therefore to drug uptake and the therapeutic effects of macromolecular agents. PMID:27079466

  10. A description of chloride cell and kidney tubule alterations in the flatfish Solea senegalensis exposed to moderately contaminated sediments from the Sado estuary (Portugal)

    NASA Astrophysics Data System (ADS)

    Costa, Pedro M.; Caeiro, Sandra; Diniz, Mário S.; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; DelValls, T. Ángel; Costa, M. Helena

    2010-11-01

    The effects of sediment-bound contaminants on kidney and gill chloride cells were surveyed in juvenile Solea senegalensis exposed to fresh sediments collected from three distinct sites of the Sado Estuary (Portugal) in a 28-day laboratorial assay. Sediments were analyzed for metallic contaminants, polycyclic aromatic hydrocarbons and organochlorines as well as for total organic matter, redox potential and fine fraction. The potential for causing adverse biological effects of each surveyed sediment was assessed by comparison of contaminant levels to available guidelines for coastal sediments, namely the Threshold Effects Level ( TEL) and the Probable Effects Level ( PEL). The Sediment Quality Guideline Quotient indices ( SQGQ) were calculated to compare the overall contamination levels of the three stations. A qualitative approach was employed to analyze the histo/cytopathological traits in gill chloride cells and body kidney of fish exposed to each tested sediment for 0, 14 and 28 days. The results showed that sediment contamination can be considered low to moderate and that the least contaminated sediment (from a reference site, with the lowest SQGQ) caused lesser changes in the surveyed organs. However, the most contaminated sediment (by both metallic and organic xenobiotics, with highest SQGQ) was neither responsible for the highest mortality nor for the most pronounced lesions. Exposure to the sediment presenting an intermediate SQGQ, essentially contaminated by organic compounds, caused the highest mortality (48%) and the most severe damage to kidneys, up to full renal necrosis. Chloride cell alterations were similar in fish exposed to the two most contaminated sediments and consisted of a pronounced cellular hypertrophy, likely involving fluid retention and loss of mitochondria. It can be concluded that sediment contamination considered to be low or moderate may be responsible for severe injury to cells and parenchyma involved in the maintenance of osmotic

  11. Interactive volume exploration for feature detection and quantification in industrial CT data.

    PubMed

    Hadwiger, Markus; Laura, Fritz; Rezk-Salama, Christof; Höllt, Thomas; Geier, Georg; Pabel, Thomas

    2008-01-01

    This paper presents a novel method for interactive exploration of industrial CT volumes such as cast metal parts, with the goal of interactively detecting, classifying, and quantifying features using a visualization-driven approach. The standard approach for defect detection builds on region growing, which requires manually tuning parameters such as target ranges for density and size, variance, as well as the specification of seed points. If the results are not satisfactory, region growing must be performed again with different parameters. In contrast, our method allows interactive exploration of the parameter space, completely separated from region growing in an unattended pre-processing stage. The pre-computed feature volume tracks a feature size curve for each voxel over time, which is identified with the main region growing parameter such as variance. A novel 3D transfer function domain over (density, feature size, time) allows for interactive exploration of feature classes. Features and feature size curves can also be explored individually, which helps with transfer function specification and allows coloring individual features and disabling features resulting from CT artifacts. Based on the classification obtained through exploration, the classified features can be quantified immediately. PMID:18989003

  12. Excluded volume effects in macromolecular forces and ion-interface interactions.

    PubMed

    Buyukdagli, Sahin; Ala-Nissila, T

    2012-02-21

    A charged Yukawa liquid confined in a slit nanopore is studied in order to understand excluded volume effects in the interaction force between the pore walls. A previously developed self-consistent scheme [S. Buyukdagli, C. V. Achim, and T. Ala-Nissila, J. Stat. Mech. 2011, P05033] and a new simpler variational procedure that self-consistently couple image forces, surface charge induced electric field, and pore modified core interactions are used to this aim. For neutral pores, it is shown that with increasing pore size, the theory predicts a transition of the interplate pressure from an attractive to a strongly repulsive regime associated with an ionic packing state, an effect observed in previous Monte Carlo simulations for hard core charges. We also establish the mean-field theory of the model and show that for dielectrically homogeneous pores, the mean-field regime of the interaction between the walls corresponds to large pores of size d > 4 Å. The role of the range of core interactions in the ionic rejection and interplate pressure is thoroughly analyzed. We show that the physics of the system can be split into two screening regimes. The ionic packing effect takes place in the regime of moderately screened core interactions characterized with the bare screening parameter of the Yukawa potential b ≲ 3/l(B), where l(B) is the Bjerrum length. In the second regime of strongly screened core interactions b ≳ 3/l(B), solvation forces associated with these interactions positively contribute to the ionic rejection driven by electrostatic forces and enhance the magnitude of the attractive pressure. For weakly charged pores without a dielectric discontinuity, core interactions make a net repulsive contribution to the interplate force and also result in oscillatory pressure curves, whereas for intermediate surface charges, these interactions exclusively strengthen the external pressure, thereby reducing the magnitude of the net repulsive interplate force. The

  13. Sexually dimorphic brain volume interaction in college-aged binge drinkers

    PubMed Central

    Kvamme, Timo L.; Schmidt, Casper; Strelchuk, Daniela; Chang-Webb, Yee Chien; Baek, Kwangyeol; Voon, Valerie

    2015-01-01

    Background Binge consumption of alcohol is a major societal problem associated with important cognitive, physiological and neurotoxic consequences. Converging evidence highlights the need to assess binge drinking (BD) and its effects on the developing brain while taking into account gender differences. Here, we compared the brain volumetric differences between genders in college-aged binge drinkers and healthy volunteers. Method T1-weighted magnetic resonance imaging (MRI) images of 30 binge drinkers (18 males) and 46 matched healthy volunteers (23 males) were examined using voxel-based morphometry. The anatomical scans were covaried with Alcohol Use Disorders Identification Test (AUDIT) scores. Whole brain voxel-wise group comparisons were performed using a cluster extent threshold correction. Results Several large clusters qualified with group-by-gender interactions were observed in prefrontal, striatal and medial temporal areas, whereby BD females had more volume than non-BD females, while males showed the inverse pattern of decreased volume in BD males and increased volume in non-BD males. AUDIT scores negatively correlated with volume in the right superior frontal cortex and precentral gyrus. Conclusions These findings dovetail with previous studies reporting that a state effect of BD in college-aged drinkers and the severity of alcohol use are associated with volumetric alterations in the cortical and subcortical areas of the brain. Our study indicates that these widespread volumetric changes vary differentially by gender, suggesting either sexual dimorphic endophenotypic risk factors, or differential neurotoxic sensitivities for males and females. PMID:26900571

  14. Bioleaching of heavy metal-contaminated sediments by indigenous Thiobacillus spp: metal solubilization and sulfur oxidation in the presence of surfactants.

    PubMed

    Seidel, H; Ondruschka, J; Morgenstern, P; Wennrich, R; Hoffmann, P

    2000-12-01

    The efficiency of surfactant application to improve or inhibit metal solubilization and sulfur oxidation kinetics during the bioleaching of heavy metal-contaminated sediments was studied in suspension-leaching experiments. The river sediment used contained large amounts of fine particles and organic matter. Three types of surfactants were tested: sodium dodecylsulfate (SDS), a C(12/14)-alkanolethoxylate (Präwozell F1214/5N), and a wettable sulfur (Netzschwefel 80 WP). Adding 10 mmol SDS/l led to transient inhibition of acidification, metal solubilization and sulfur oxidation. Inhibiting bioleaching for just 14 days required about ten times more SDS than the amount used for mine waste mitigation. The use of Präwozell resulted in poor inhibition; and using of wettable sulfur did not improve leaching efficiency. The bulk of these surfactants was sorbed onto the solid particles immediately on application, while the remainder in the aqueous phase disappeared within a few days. PMID:11152081

  15. Survival, growth, and body residues of hyalella azteca (Saussure) exposed to fipronil contaminated sediments from non-vegetated and vegetated microcosms.

    PubMed

    Kröger, Robert; Lizotte, Richard E; Moore, Matthew T

    2009-09-01

    We assessed chronic effects of fipronil and metabolite contaminated sediments from non-vegetated and Thallia dealbata vegetated wetland microcosms on Hyalella azteca during wet and dry exposures. Mean sediment concentrations (ng g(-1)) ranged from 0.72-1.26, 0.01-0.69, 0.07-0.23, and 0.49-7.87 for fipronil, fipronil-sulfide, fipronil-sulfone, and fipronil-desulfinyl, respectively. No significant differences in animal survival or growth were observed between non-vegetated and vegetated microcosms during wet or dry exposures. Mean animal body residue concentrations (ng g(-1)) ranged from 28.4-77.6, 0-30.7, and 8.3-43.8 for fipronil, fipronil-sulfide, and fipronil-sulfone. Fipronil-desulfinyl was not detected in any animal samples. PMID:19424647

  16. Local Volume TiNy Titans: gaseous dwarf-dwarf interactions in the Local Universe

    NASA Astrophysics Data System (ADS)

    Pearson, Sarah; Besla, Gurtina; Putman, Mary E.; Lutz, Katharina A.; Fernández, Ximena; Stierwalt, Sabrina; Patton, David R.; Kim, Jinhyub; Kallivayalil, Nitya; Johnson, Kelsey; Sung, Eon-Chang

    2016-06-01

    In this paper, we introduce the Local Volume TiNy Titans sample (LV-TNT), which is a part of a larger body of work on interacting dwarf galaxies: TNT . This LV-TNT sample consists of 10 dwarf galaxy pairs in the Local Universe (<30 Mpc from Milky Way), which span mass ratios of M*, 1/M*, 2 < 20, projected separations <100 kpc, and pair member masses of log(M*/M⊙) < 9.9. All 10 LV-TNT pairs have resolved synthesis maps of their neutral hydrogen, are located in a range of environments and captured at various interaction stages. This enables us to do a comparative study of the diffuse gas in dwarf-dwarf interactions and disentangle the gas lost due to interactions with haloes of massive galaxies, from the gas lost due to mutual interaction between the dwarfs. We find that the neutral gas is extended in the interacting pairs when compared to non-paired analogues, indicating that gas is tidally pre-processed. Additionally, we find that the environment can shape the H I distributions in the form of trailing tails and that the gas is not unbound and lost to the surroundings unless the dwarf pair is residing near a massive galaxy. We conclude that a nearby, massive host galaxy is what ultimately prevents the gas from being re-accreted. Dwarf-dwarf interactions thus represent an important part of the baryon cycle of low-mass galaxies, enabling the `parking' of gas at large distances to serve as a continual gas supply channel until accretion by a more massive host.

  17. A finite volume Euler calculation of the aerodynamics of transonic airfoil-vortex interaction

    NASA Technical Reports Server (NTRS)

    Damodaran, Murali; Caughey, David A.

    1987-01-01

    Unsteady inviscid transonic airfoil-vortex interaction is numerically analyzed by solving the two-dimensional unsteady Euler equations in integral form using a finite volume scheme. The solution procedure is based on an explicit Runge-Kutta time-stepping scheme wherein the spatial terms are central-differenced and a combination of second- and fourth-differences in the flow variables is used to form the numerical dissipation terms to stabilize the scheme. A velocity decomposition technique is applied to alleviate the problem of vortex diffusion by the numerical dissipation terms and to treat the interaction of a Rankine vortex with an airfoil accurately. Results obtained are compared with available numerical data.

  18. Effect of hydrodynamic interaction on the free volume distribution of SGFR-PBT composites

    NASA Astrophysics Data System (ADS)

    Munirathnamma, L. M.; Ningaraju, S.; Kumar, K. V. Aneesh; Ravikumar, H. B.

    2016-05-01

    In order to explore the effect of short glass fiber (SGF) reinforcement on the mechanical properties of Polybutylene terephthalate (PBT), short glass fibers of different proportion (10 - 40 wt %) are reinforced into PBT matrix. The free volume distribution of SGFR-PBT composites derived from CONTIN-PALS2 program exhibits the narrow full width at half maximum (FWHM). This is attributed to the improved adhesion resulted by the hydrodynamic interaction between the polymeric chains of PBT matrix and SGF. The hydrodynamic interaction parameter (h) decreases as a function of SGF wt% and becomes more negative for 40 wt% SGFR-PBT composites suggest the generation of excess friction at the interface. This improves the adhesion between the polymeric chains of PBT matrix and SGF and hence the mechanical strength of the SGFR-PBT composites.

  19. Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments

    USGS Publications Warehouse

    Stoliker, Deborah L.; Liu, Chongxuan; Kent, Douglas B.; Zachara, John M.

    2013-01-01

    Rates of U(VI) release from individual dry-sieved size fractions of a field-aggregated, field-contaminated composite sediment from the seasonally saturated lower vadose zone of the Hanford 300-Area were examined in flow-through reactors to maintain quasi-constant chemical conditions. The principal source of variability in equilibrium U(VI) adsorption properties of the various size fractions was the impact of variable chemistry on adsorption. This source of variability was represented using surface complexation models (SCMs) with different stoichiometric coefficients with respect to hydrogen ion and carbonate concentrations for the different size fractions. A reactive transport model incorporating equilibrium expressions for cation exchange and calcite dissolution, along with rate expressions for aerobic respiration and silica dissolution, described the temporal evolution of solute concentrations observed during the flow-through reactor experiments. Kinetic U(VI) desorption was well described using a multirate SCM with an assumed lognormal distribution for the mass-transfer rate coefficients. The estimated mean and standard deviation of the rate coefficients were the same for all <2 mm size fractions but differed for the 2–8 mm size fraction. Micropore volumes, assessed using t-plots to analyze N2 desorption data, were also the same for all dry-sieved <2 mm size fractions, indicating a link between micropore volumes and mass-transfer rate properties. Pore volumes for dry-sieved size fractions exceeded values for the corresponding wet-sieved fractions. We hypothesize that repeated field wetting and drying cycles lead to the formation of aggregates and/or coatings containing (micro)pore networks which provided an additional mass-transfer resistance over that associated with individual particles. The 2–8 mm fraction exhibited a larger average and standard deviation in the distribution of mass-transfer rate coefficients, possibly caused by the abundance of

  20. A coupled modelling effort to study the fate of contaminated sediments downstream of the Coles Hill deposit, Virginia, USA

    NASA Astrophysics Data System (ADS)

    Castro-Bolinaga, C. F.; Zavaleta, E. R.; Diplas, P.

    2015-03-01

    This paper presents the preliminary results of a coupled modelling effort to study the fate of tailings (radioactive waste-by product) downstream of the Coles Hill uranium deposit located in Virginia, USA. The implementation of the overall modelling process includes a one-dimensional hydraulic model to qualitatively characterize the sediment transport process under severe flooding conditions downstream of the potential mining site, a two-dimensional ANSYS Fluent model to simulate the release of tailings from a containment cell located partially above the local ground surface into the nearby streams, and a one-dimensional finite-volume sediment transport model to examine the propagation of a tailings sediment pulse in the river network located downstream. The findings of this investigation aim to assist in estimating the potential impacts that tailings would have if they were transported into rivers and reservoirs located downstream of the Coles Hill deposit that serve as municipal drinking water supplies.

  1. Detailed requirements document for the Interactive Financial Management System (IFMS), volume 1

    NASA Technical Reports Server (NTRS)

    Dodson, D. B.

    1975-01-01

    The detailed requirements for phase 1 (online fund control, subauthorization accounting, and accounts receivable functional capabilities) of the Interactive Financial Management System (IFMS) are described. This includes information on the following: systems requirements, performance requirements, test requirements, and production implementation. Most of the work is centered on systems requirements, and includes discussions on the following processes: resources authority, allotment, primary work authorization, reimbursable order acceptance, purchase request, obligation, cost accrual, cost distribution, disbursement, subauthorization performance, travel, accounts receivable, payroll, property, edit table maintenance, end-of-year, backup input. Other subjects covered include: external systems interfaces, general inquiries, general report requirements, communication requirements, and miscellaneous. Subjects covered under performance requirements include: response time, processing volumes, system reliability, and accuracy. Under test requirements come test data sources, general test approach, and acceptance criteria. Under production implementation come data base establishment, operational stages, and operational requirements.

  2. Cadmium, metal-binding proteins, and growth in bluegill (Lepomis macrochirus) exposed to contaminated sediments from the upper Mississippi River basin

    USGS Publications Warehouse

    Cope, W.G.; Wiener, J.G.; Steingraeber, M.T.; Atchison, G.J.

    1994-01-01

    We exposed juvenile bluegill (Lepomis macrochirus) to ~1000 mg·L-1 of continuously suspended river sediment in a 28-d test with six treatments (randomized block with one sediment-free control and five sediments ranging from 1.3 to 21.4 μg Cd·g dry weight-1). Each treatment had three replicates, each with 25 fish. Growth was reduced by exposure to suspended sediment, probably due to physical effects of sediment on feeding and to toxicity in the treatment with the greatest concentrations of metals. Mean whole-body concentrations of cadmium (0.04–0.14 μg wet weight-1) were correlated with cadmium concentration in filtered water (8–72 ng·L-1), suspended sediment (0.61–16.8 μg·L-1), and bulk sediment. The concentration of hepatic nonthionein cytosolic cadmium (cadmium not bound by metal-binding proteins, MBP) in fish exposed to the two most contaminated sediments exceeded that in controls. The mean concentration of hepatic MBP was correlated with cadmium concentration in filtered water, suspended sediment, bulk sediment, and whole fish. Whole-body cadmium concentration was the most sensitive indicator of cadmium exposure, with lowest observed effect concentrations of 1.9 μg Cd·L-1 for suspended sediment and 13 ng Cd·L-1 for filtered water. Sediment-associated cadmium was less available than waterborne cadmium for uptake by fish.

  3. Cation exchange reactions controlling desorption of Sr-90(2+) from coarse-grained contaminated sediments at the Hanford site, Washington

    SciTech Connect

    McKinley, James P.; Zachara, John M.; Smith, Steven C.; Liu, Chongxuan

    2007-01-15

    Nuclear waste that bore 90Sr2+ was accidentally leaked into the vadose zone at the Hanford site, and was immobilized at relatively shallow depths in sediments containing little apparent clay or silt-sized components. Sr2+, 90Sr2+, Mg2+, and Ca2+ was desorbed and total inorganic carbon concentration was monitored during the equilibration of this sediment with varying concentrations of Na+, Ca2+. A cation exchange model previously developed for similar sediments was applied to these results as a predictor of final solution compositions. The model included binary exchange reactions for the four operant cations and an equilibrium dissolution/precipitation reaction for calcite. The model successfully predicted the desorption data. The contaminated sediment was also examined using digital autoradiography, a sensitive tool for imaging the distribution of radioactivity. The exchanger phase containing 90Sr was found to consist of smectite formed from weathering of mesostasis glass in basaltic lithic fragments. These clasts are a significant component of Hanford formation sands. The relatively small but significant cation exchange capacity of these sediments was thus a consequence of reaction with physically sequestered clays in sediment that contained essentially no fine-grained material. The nature of this exchange component explained the relatively slow (scale of days) evolution of desorption solutions. The experimental and model results indicated that there is little risk of migration of 90Sr2+ to the water table.

  4. Accumulation of polychlorinated biphenyls from contaminated sediment by Atlantic cod (Gadus morhua): direct accumulation from resuspended sediment and dietary accumulation via the polychaete Nereis virens.

    PubMed

    Ruus, Anders; Daae, Ingrid Aarre; Hylland, Ketil

    2012-11-01

    Bioaccumulation of sediment-associated polychlorinated biphenyls (PCBs) was examined in Atlantic cod (Gadus morhua) through direct diffusion from the sediment (via the water phase) and through the food chain (dietary exposure). To facilitate direct accumulation from the sediment, it was continuously resuspended. To study the dietary bioaccumulation of PCBs, cod were fed benthic polychaetes (Nereis virens) previously exposed to test sediments, which were naturally polluted sediments from the inner Oslofjord (Norway). Both exposure experiments had a duration of 129 d. Furthermore, the role of sediments as a source of PCBs accumulated in Oslofjord cod was elucidated, using results from environmental monitoring as a reference. Generally, the results suggest that the contaminated sediments of the inner Oslofjord are an important source of legacy PCBs for accumulation in resident cod, although additional contributions may also be important. Crude estimates of assimilation efficiency of ingested PCBs (through diet) were found to be 30 to 50%; the highest was for the lower chlorinated congeners (PCB-28 and -52). Challenges for applying trophic magnification factors for determining biomagnification in laboratory experiments, in terms of preventive environmental safety, are indicated. The results provide useful information for parameterization of models describing the behavior of hydrophobic persistent contaminants in the foodweb of the Oslofjord and elsewhere. PMID:22865726

  5. Trace metal fractionation as a mean to improve on the management of contaminated sediments from runoff water in infiltration basins.

    PubMed

    Al Husseini, Amelène El-Mufleh; Béchet, Béatrice; Gaudin, Anne; Ruban, Véronique

    2013-01-01

    The management of stormwater sediment is a key issue for local authorities due to the pollution load and significant tonnages. In view of reuse, for example for civil engineering, the environmental evaluation of these highly aggregated sediments requires the study of the fractionation and mobility of trace metals. The distribution of trace metals (Cd, Cr, Cu, Ni, Pb, Zn) and their level of lability in three French stormwater sediments was determined using sequential and kinetic extractions (EDTA reagent) associated with mineralogical analysis and scanning electron microscopy observations. Using microanalysis, new data were acquired on the evolution of aggregate state during extractions, and on its significant role in the retention of trace metals. Trace metals were, in particular, observed to be very stable in small aggregates (10-50 microm). Comparison of the two extraction methods revealed that EDTA extraction was not convenient for evaluating the stable fraction of Cr, Ni and Zn. Moreover, the results were relevant for basins presenting similar sources of trace metals, whatever the physicochemical conditions in basins. The results suggest that the management of stormwater sediments could be improved by a better knowledge of metal mobility, as chemical extractions could highlight the localization of the mobile fraction of trace metals. Treatment could be therefore avoided, or specific treatment could be applied to a reduced volume of sediments. PMID:24191459

  6. Potential accumulation of contaminated sediments in a reservoir of a high-Andean watershed: Morphodynamic connections with geochemical processes

    NASA Astrophysics Data System (ADS)

    Contreras, María. Teresa; Müllendorff, Daniel; Pastén, Pablo; Pizarro, Gonzalo E.; Paola, Chris; Escauriaza, Cristián.

    2015-05-01

    Rapid changes due to anthropic interventions in high-altitude environments, such as the Altiplano region in South America, require new approaches to understand the connections between physical and geochemical processes. Alterations of the water quality linked to the river morphology can affect the ecosystems and human development in the long term. The future construction of a reservoir in the Lluta River, located in northern Chile, will change the spatial distribution of arsenic-rich sediments, which can have significant effects on the lower parts of the watershed. In this investigation, we develop a coupled numerical model to predict and evaluate the interactions between morphodynamic changes in the Lluta reservoir, and conditions that can potentially desorb arsenic from the sediments. Assuming that contaminants are mobilized under anaerobic conditions, we calculate the oxygen concentration within the sediments to study the interactions of the delta progradation with the potential arsenic release. This work provides a framework for future studies aimed to analyze the complex connections between morphodynamics and water quality, when contaminant-rich sediments accumulate in a reservoir. The tool can also help to design effective risk management and remediation strategies in these extreme environments. This article was corrected on 15 JUNE 2015. See the end of the full text for details.

  7. Numerical simulation of fluid-structure interaction with the volume penalization method

    NASA Astrophysics Data System (ADS)

    Engels, Thomas; Kolomenskiy, Dmitry; Schneider, Kai; Sesterhenn, Jörn

    2015-01-01

    We present a novel scheme for the numerical simulation of fluid-structure interaction problems. It extends the volume penalization method, a member of the family of immersed boundary methods, to take into account flexible obstacles. We show how the introduction of a smoothing layer, physically interpreted as surface roughness, allows for arbitrary motion of the deformable obstacle. The approach is carefully validated and good agreement with various results in the literature is found. A simple one-dimensional solid model is derived, capable of modeling arbitrarily large deformations and imposed motion at the leading edge, as it is required for the simulation of simplified models for insect flight. The model error is shown to be small, while the one-dimensional character of the model features a reasonably easy implementation. The coupled fluid-solid interaction solver is shown not to introduce artificial energy in the numerical coupling, and validated using a widely used benchmark. We conclude with the application of our method to models for insect flight and study the propulsive efficiency of one and two wing sections.

  8. Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments

    SciTech Connect

    Stoliker, Deborah L.; Liu, Chongxuan; Kent, Douglas B.; Zachara, John M.

    2013-02-12

    Rates of contaminant U(VI) release from individual size fractions of a composite sediment from the seasonally saturated lower vadose zone of the Hanford 300-Area were examined in flow-through batch reactors to maintain quasi-constant chemical conditions. Variability in equilibrium adsorption among the various size fractions was determined in static batch reactors and analyzed using the surface complexation modeling approach. The estimated stoichiometric coefficients of U(VI) surface complexation reactions with respect to pH and carbonate concentrations varied with size fractions. This source of variability significantly increased the uncertainty in U(VI) conditional equilibrium constants over that estimated from experimental errors alone. A minimum difference between conditional equilibrium constants was established in order to evaluate statistically significant differences between sediment adsorption properties. A set of equilibrium and kinetic expressions for cation exchange, calcite dissolution, aerobic respiration, and silica dissolution were incorporated in a reaction-rate model to describe the temporal evolution of solute concentrations observed during the flow-through batch experiments. Parameters in the reaction-rate model, calibrated using experimental data for select size fractions, predicted the changes in solute concentrations for the bulk, <2 mm, sediment sample. Kinetic U(VI) desorption was well described using a multi-rate surface complexation model with an assumed lognormal distribution for the rate constants. The estimated mean and standard deviation were the same for all < 2mm size fractions, but differed in the 2-8mm size fraction. Micropore volumes in the varied size fractions were also similar as assessed using t-plots to analyze N2 desorption data. These findings provide further support for the link between microporosity and particle-scale mass transfer rates controlling kinetic U(VI) adsorption/desorption and for the utility of N2 desorption

  9. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    USGS Publications Warehouse

    Bothner, Michael H., (Edited By); Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  10. Assumption of separability of the excluded-volume interaction in polymer physics: Flory-Huggins theory reviewed

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Somendra M.

    1986-08-01

    Rotational isomerism and the excluded-volume interaction are generally considered to be the two major factors in polymer crystallization, glass transition, etc. The calculations supporting this belief are based on the assumption that the contribution to the free energy from the excluded-volume interaction is separable from the rest of the interactions. This separability assumption is studied here by mapping a single-polymer-chain problem to a spin problem with a cluster interaction. Using a variational principle, which provides an upper bound to the free energy, it is shown that the separability assumption gives a qualitatively incorrect description of the system in the low-temperature region. The consequences of this result for general models are also discussed.

  11. Seismic design technology for breeder reactor structures. Volume 2. Special topics in soil/structure interaction analyses

    SciTech Connect

    Reddy, D.P.

    1983-04-01

    This volume is divided into six chapters: definition of seismic input ground motion, review of state-of-the-art procedures, analysis guidelines, rock/structure interaction analysis example, comparison of two- and three-dimensional analyses, and comparison of analyses using FLUSH and TRI/SAC Codes. (DLC)

  12. Bicarbonate-water interactions in the rat proximal convoluted tubule. An effect of volume flux on active proton secretion

    PubMed Central

    1984-01-01

    The effect of volume absorption on bicarbonate absorption was examined in the in vivo perfused rat proximal convoluted tubule. Volume absorption was inhibited by isosmotic replacement of luminal NaCl with raffinose. In tubules perfused with 25 mM bicarbonate, as raffinose was increased from 0 to 55 to 63 mM, volume absorption decreased from 2.18 +/- 0.10 to 0.30 +/- 0.18 to -0.66 +/- 0.30 nl/mm X min, respectively, and bicarbonate absorption decreased from 131 +/- 5 to 106 +/- 8 to 91 +/- 13 pmol/mm X min, respectively. This bicarbonate-water interaction could not be attributed to dilutional changes in luminal or peritubular bulk phase bicarbonate concentrations. Inhibition of active proton secretion by acetazolamide abolished the effect of volume flow on bicarbonate absorption, which implies that the bicarbonate reflection coefficient is close to 1 and eliminates the possibility of solvent drag across the tight junction. When the luminal bicarbonate concentration was varied, the magnitude of the bicarbonate-water interaction increased with increasing luminal bicarbonate concentration. The largest interaction occurred at high luminal bicarbonate concentrations, where the rate of proton secretion has been previously shown to be independent of luminal bicarbonate concentration and pH. The results thus suggest that a peritubular and/or cellular compartment exists that limits bicarbonate diffusion, and where pH changes secondary to bicarbonate-water interactions (solute polarization) alter the rate of active proton secretion. PMID:6096481

  13. Classroom Interactions in Four Follow Through Sites. Volume III, Progress Report, Cognitively Oriented Curriculum, Project Follow Through.

    ERIC Educational Resources Information Center

    Morris, Mary E.; Love, John M.

    Volume III presents the results of High/Scope Foundation's Analysis of Classroom Interaction, a classroom observation instrument field tested at four projects. The purpose of this study was to assess the consistency of implementation of the Cognitively Oriented Curriculum in the four widely separated communities in which the High/Scope Foundation…

  14. Effects of excluded volume and hydrodynamic interaction on the deformation, orientation and motion of ring polymers in shear flow.

    PubMed

    Chen, Wenduo; Zhao, Hongchao; Liu, Lijun; Chen, Jizhong; Li, Yunqi; An, Lijia

    2015-07-14

    A ring polymer is a classical model to explore the behaviors of biomacromolecules. Compared with its linear counterpart in shear flow, the ring polymer should be more sensitive to excluded volume and hydrodynamic interaction attributed to the absence of chain ends. We carried out multiparticle collision dynamics combined with molecular dynamics simulation to study the effects of excluded volume and hydrodynamic interaction on the behaviors of ring polymers in shear flow. The results show that in the absence of the strong excluded volume interaction, the ring polymer prefers a two-strand linear conformation with high deformation and orientation in the flow-gradient plane, and the tank-treading motion is nearly negligible. Ring polymers without excluded volume show no significant difference from linear polymers in the scaling exponents for the deformation, orientation and tumbling motion. We also observed that the hydrodynamic interaction could efficiently slow down the relaxation of ring polymers while the scaling exponents against the Weissenberg number have rarely been affected. PMID:26053427

  15. The broad-host-range plasmid pSFA231 isolated from petroleum-contaminated sediment represents a new member of the PromA plasmid family

    PubMed Central

    Li, Xiaobin; Top, Eva M.; Wang, Yafei; Brown, Celeste J.; Yao, Fei; Yang, Shan; Jiang, Yong; Li, Hui

    2015-01-01

    A self-transmissible broad-host-range (BHR) plasmid pSFA231 was isolated from petroleum-contaminated sediment in Shen-fu wastewater irrigation zone, China, using the triparental mating exogenous plasmid capture method. Based on its complete sequence the plasmid has a size of 41.5 kb and codes for 50 putative open reading frames (orfs), 29 of which represent genes involved in replication, partitioning and transfer functions of the plasmid. Phylogenetic analysis grouped pSFA231 into the newly defined PromA plasmid family, which currently includes five members. Further comparative genomic analysis shows that pSFA231 shares the common backbone regions with the other PromA plasmids, i.e., genes involved in replication, maintenance and control, and conjugative transfer. Nevertheless, phylogenetic divergence was found in specific gene products. We propose to divide the PromA group into two subgroups, PromA-α (pMRAD02, pSB102) and PromA-β (pMOL98, pIPO2T, pSFA231, pTer331), based on the splits network analysis of the RepA protein. Interestingly, a cluster of hypothetical orfs located between parA and traA of pSFA231 shows high similarity with the corresponding regions on pMOL98, pIPO2T, and pTer331, suggesting these hypothetical orfs may represent “essential” plasmid backbone genes for the PromA-β subgroup. Alternatively, they may also be accessory genes that were first acquired and then stayed as the plasmid diverged. Our study increases the available collection of complete genome sequences of BHR plasmids, and since pSFA231 is the only characterized PromA plasmid from China, our findings also enhance our understanding of the genetic diversity of this plasmid group in different parts of the world. PMID:25628616

  16. Treatment of urban river contaminated sediment with ex situ advanced oxidation processes: technical feasibility, environmental discharges and cost-performance analysis.

    PubMed

    Yan, Dickson Y S; Liu, Tongzhou; Lo, Irene M C

    2015-01-01

    The technical feasibility, environmental discharges and cost-performance of urban river contaminated sediment treatment with ex situ advanced oxidation processes were evaluated for the purpose of achieving an ideal treatment goal (for marine disposal) and a cost-performance treatment goal (for beneficially reusing as a filling material). Sediment samples were collected from a river located in southern China. To achieve the ideal treatment goal, sequential treatments (Fenton's reaction+activated persulphate oxidation) were carried out. One-step Fenton's reaction was applied to achieve the cost-performance treatment goal. The resulting effluent was treated and discharged, and sludge generated in wastewater treatment was characterized. The resources input throughout the treatment processes were recorded for cost estimation. After the treatment designed for achieving the ideal treatment goal, most pollutants fulfilled the treatment goal except Pb, Cd, Hg and Ag, probably because these four metals were present mainly in stable fractions of the sediment. The cost-performance treatment goal was achieved in view of low pollutant contents in the toxicity characteristic leaching procedure leachate of treated sediment. The cost for achieving the cost-performance treatment goal is much less than that for achieving the ideal treatment goal. The major cost difference is attributed to chemical cost. Stringent sediment treatment goals based on existing standards would lead to massive chemical use, complex treatment and hence huge cost. A simpler treatment with fewer chemicals is adequate for sediment beneficially reused as a filling material, and is economically more advantageous than handling sediment for marine disposal. PMID:25687695

  17. Regional gray matter volume and anxiety-related traits interact to predict somatic complaints in a non-clinical sample.

    PubMed

    Wei, Dongtao; Du, Xue; Li, Wenfu; Chen, Qunlin; Li, Haijiang; Hao, Xin; Zhang, Lei; Hitchman, Glenn; Zhang, Qinglin; Qiu, Jiang

    2015-01-01

    Somatic complaints can be important features of an individual's expression of anxiety. Anxiety-related traits are also risk factors for somatic symptoms. However, it is not known which neuroanatomical mechanisms may be responsible for this relationship. In this study, our first step was to use voxel-based morphometry (VBM) approaches to investigate the neuroanatomical basis underlying somatic complaints in a large sample of healthy subjects. We found a significant positive correlation between somatic complaints and parahippocampal gyrus (PHG) volume adjacent to the entorhinal cortex. Further analysis revealed that the interaction between PHG volume/entorhinal cortex and neuroticism-anxiety (N-Anx) predicted somatic complaints. Specifically, somatic complaints were associated with higher N-Anx for individuals with increased PHG volume. These findings suggest that increased PHG volume and higher trait anxiety can predict vulnerability to somatic complaints in the general population. PMID:24622213

  18. Regional gray matter volume and anxiety-related traits interact to predict somatic complaints in a non-clinical sample

    PubMed Central

    Wei, Dongtao; Du, Xue; Li, Wenfu; Chen, Qunlin; Li, Haijiang; Hao, Xin; Zhang, Lei; Hitchman, Glenn; Zhang, Qinglin

    2015-01-01

    Somatic complaints can be important features of an individual’s expression of anxiety. Anxiety-related traits are also risk factors for somatic symptoms. However, it is not known which neuroanatomical mechanisms may be responsible for this relationship. In this study, our first step was to use voxel-based morphometry (VBM) approaches to investigate the neuroanatomical basis underlying somatic complaints in a large sample of healthy subjects. We found a significant positive correlation between somatic complaints and parahippocampal gyrus (PHG) volume adjacent to the entorhinal cortex. Further analysis revealed that the interaction between PHG volume/entorhinal cortex and neuroticism-anxiety (N-Anx) predicted somatic complaints. Specifically, somatic complaints were associated with higher N-Anx for individuals with increased PHG volume. These findings suggest that increased PHG volume and higher trait anxiety can predict vulnerability to somatic complaints in the general population. PMID:24622213

  19. Separating chemical and excluded volume interactions of polyethylene glycols with native proteins: Comparison with PEG effects on DNA helix formation.

    PubMed

    Shkel, Irina A; Knowles, D B; Record, M Thomas

    2015-09-01

    Small and large PEGs greatly increase chemical potentials of globular proteins (μ2), thereby favoring precipitation, crystallization, and protein-protein interactions that reduce water-accessible protein surface and/or protein-PEG excluded volume. To determine individual contributions of PEG-protein chemical and excluded volume interactions to μ2 as functions of PEG molality m3 , we analyze published chemical potential increments μ23  = dμ2/dm3 quantifying unfavorable interactions of PEG (PEG200-PEG6000) with BSA and lysozyme. For both proteins, μ23 increases approximately linearly with the number of PEG residues (N3). A 1 molal increase in concentration of PEG -CH2 OCH2 - groups, for any chain-length PEG, increases μBSA by ∼2.7 kcal/mol and μlysozyme by ∼1.0 kcal/mol. These values are similar to predicted chemical interactions of PEG -CH2 OCH2 - groups with these protein components (BSA ∼3.3 kcal/mol, lysozyme ∼0.7 kcal/mol), dominated by unfavorable interactions with amide and carboxylate oxygens and counterions. While these chemical effects should be dominant for small PEGs, larger PEGS are expected to exhibit unfavorable excluded volume interactions and reduced chemical interactions because of shielding of PEG residues in PEG flexible coils. We deduce that these excluded volume and chemical shielding contributions largely compensate, explaining why the dependence of μ23 on N3 is similar for both small and large PEGs. PMID:25924886

  20. Calculation of the Radius of Gyration for a Linear Flexible Polymer Chain with Excluded Volume Interaction.

    NASA Astrophysics Data System (ADS)

    Shanes, Fredrick Charles

    1990-01-01

    We have calculated the radius of gyration for a three dimensional linear flexible polymer chain with excluded volume interaction. The resulting < S^2> is written as a perturbation series in the dimensionless excluded volume parameter z, and the series is written to O(z ^4) as = (Ll/6)(1 + 1.276190476z - 2.081948603z^2 + 6.564897382z^3 - 26.70629003z^4 + ...) where z = (3/2pil) ^{3/2}omegaL^ {1/2} with l the effective segment length, L the contour length, and omegal^2 the effective binary cluster integral for a pair of segments. The perturbation theory used to calculate has recently been applied to the mean square end-to-end distance for a linear flexible polymer chain by Muthukumar and Nickel. The theory essentially uses the continuum limit of the two -parameter model, Laplace transforms, and a diagrammatic expansion in conjunction with field theory methods. The perturbation theory was found to be much simpler to implement than the usual cluster expansion method, and thus we were able to extend the series from the previously known O(z^2) to O(z^4 ). The perturbation series for < S^2> and are divergent, and are only valid for small z values. However, the most interesting information about these properties occurs for large z values. The large z limit of the and series were extracted by using the direct renormalization method, and estimates for the critical exponents and scaling amplitudes were obtained. A quantity that is of theoretical interest is the large z limit of the ratio 6/< R^2>, since it is believed to be a universal constant (i.e., independent of the model). We calculated the ratio by applying four different renormalization schemes to the perturbation series for and , and we obtained a final estimate of 6 / = 0.9631 +/- 0.0003. We also analysed the Monte Carlo self-avoiding walk data for the ratio and found the large chain limit of 6 / = 0.9602 +/- 0.0002. The

  1. Inclusion of fluid-solid interaction in Volume of Fluid to simulate spreading and dewetting for large contact angles

    NASA Astrophysics Data System (ADS)

    Mahady, Kyle; Afkhami, Shahriar; Kondic, Lou

    2014-11-01

    The van der Waals (vdW) interaction between molecules is of fundamental importance in determining the behavior of three phase systems in fluid mechanics. This interaction gives rise to interfacial energies, and thus the contact angle for a droplet on a solid surface, and additionally leads to instability of very thin liquid films. We develop a hybrid method for including a Lennard-Jones type vdW interaction in a finite volume, Volume of Fluid (VoF) based solver for the full two-phase Navier-Stokes equations. This method includes the full interaction between each fluid phase and the solid substrate via a finite-volume approximation of the vdW body force. Our work is distinguished from conventional VoF based implementations in that the contact angle arises from simulation of the underlying physics, as well as successfully treating vdW induced film rupture. At the same time, it avoids the simplifications of calculations based on disjoining-pressure, where the vdW interaction is included as a pressure jump across the interface which is derived under the assumption of a flat film. This is especially relevant in the simulation of nanoscale film ruptures involving large contact angles, which have been studied recently in the context of bottom-up nanoparticle fabrication. This work is partially supported by the Grants NSF DMS-1320037 and CBET-1235710.

  2. Image Data Processing System (IDAPS) user manual, S-056 experiment. Volume 1: System description. Volume 2: Batch IDAPS. Volume 3: Interactive IDAPS

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Image data processing system (IDAPS) developed to satisfy the image processing requirements of the Skylab S-056 experiment is described. The S-056 experiment was designed to obtain high-resolution photographs of the sun in the far ultraviolet, or soft X-ray, portion of the electromagnetic spectrum. Thirty-five thousand photographs were obtained by the three flights of the program; and, faced with such a massive volume of imagery, the designers of the experiment decided to develop a computer-based system which would reduce the image processing workload. The purpose of the IDAPS User Manual is to give the IDAPS user the necessary information and instructions to effectively utilize the system.

  3. CONTAMINATED SEDIMENTS - ECOLOGICAL EFFECTS RESEARCH

    EPA Science Inventory

    NHEERL's research in this area focuses on ecological effects of bioaccumulative chemicals, such as PCBs. The research is designed with recognition that sites of different size and complexity require bioaccumulation models with correspondingly complex and/or extensive data requir...

  4. Interaction of the endocrine system with inflammation: a function of energy and volume regulation.

    PubMed

    Straub, Rainer H

    2014-01-01

    During acute systemic infectious disease, precisely regulated release of energy-rich substrates (glucose, free fatty acids, and amino acids) and auxiliary elements such as calcium/phosphorus from storage sites (fat tissue, muscle, liver, and bone) are highly important because these factors are needed by an energy-consuming immune system in a situation with little or no food/water intake (sickness behavior). This positively selected program for short-lived infectious diseases is similarly applied during chronic inflammatory diseases. This review presents the interaction of hormones and inflammation by focusing on energy storage/expenditure and volume regulation. Energy storage hormones are represented by insulin (glucose/lipid storage and growth-related processes), insulin-like growth factor-1 (IGF-1) (muscle and bone growth), androgens (muscle and bone growth), vitamin D (bone growth), and osteocalcin (bone growth, support of insulin, and testosterone). Energy expenditure hormones are represented by cortisol (breakdown of liver glycogen/adipose tissue triglycerides/muscle protein, and gluconeogenesis; water retention), noradrenaline/adrenaline (breakdown of liver glycogen/adipose tissue triglycerides, and gluconeogenesis; water retention), growth hormone (glucogenic, lipolytic; has also growth-related aspects; water retention), thyroid gland hormones (increase metabolic effects of adrenaline/noradrenaline), and angiotensin II (induce insulin resistance and retain water). In chronic inflammatory diseases, a preponderance of energy expenditure pathways is switched on, leading to typical hormonal changes such as insulin/IGF-1 resistance, hypoandrogenemia, hypovitaminosis D, mild hypercortisolemia, and increased activity of the sympathetic nervous system and the renin-angiotensin-aldosterone system. Though necessary during acute inflammation in the context of systemic infection or trauma, these long-standing changes contribute to increased mortality in chronic

  5. Interaction of hyperthermia and heart rate on stroke volume during prolonged exercise.

    PubMed

    Trinity, Joel D; Pahnke, Matthew D; Lee, Joshua F; Coyle, Edward F

    2010-09-01

    People who become hyperthermic during exercise display large increases in heart rate (HR) and reductions in stroke volume (SV). It is not clear if the reduction in SV is due primarily to hyperthermia or if it is a secondary effect of an elevation in HR reducing ventricular filling. In the present study, the upward drift of HR during prolonged exercise was prevented by a very small dose of the β1-adrenoreceptor blocker (atenolol; βB), thus allowing SV to be compared at a given HR during normothermia and hyperthermia. Eleven men cycled for 60 min at 57% of peak O2 uptake after receiving placebo control (PL) or a low dose (0.2 mg/kg) of βB. Hyperthermia was induced by reducing heat dissipation during exercise. Four experimental conditions were studied: normothermia-PL, normothermia-βB, hyperthermia-PL, and hyperthermia-βB. Hyperthermia increased skin and core temperature by 4.3 degrees C and 0.8 degrees C (P<0.01), respectively. βB prevented HR elevation with hyperthermia: HR values were similar at minute 60 during normothermia-PL and hyperthermia-βB (155±11 and 154±13 beats/min, respectively, P=0.82). However, SV was increased by 7% during the final 20 min of exercise during hyperthermia-βB compared with normothermia-PL (treatment×time interaction, P=0.03). In conclusion, when matched for HR, mild hyperthermia increased SV during exercise. Furthermore, the reduction in SV throughout prolonged exercise under normothermic and mildly hyperthermic conditions appears to be due to the increase in HR. PMID:20595543

  6. Interaction of the endocrine system with inflammation: a function of energy and volume regulation

    PubMed Central

    2014-01-01

    During acute systemic infectious disease, precisely regulated release of energy-rich substrates (glucose, free fatty acids, and amino acids) and auxiliary elements such as calcium/phosphorus from storage sites (fat tissue, muscle, liver, and bone) are highly important because these factors are needed by an energy-consuming immune system in a situation with little or no food/water intake (sickness behavior). This positively selected program for short-lived infectious diseases is similarly applied during chronic inflammatory diseases. This review presents the interaction of hormones and inflammation by focusing on energy storage/expenditure and volume regulation. Energy storage hormones are represented by insulin (glucose/lipid storage and growth-related processes), insulin-like growth factor-1 (IGF-1) (muscle and bone growth), androgens (muscle and bone growth), vitamin D (bone growth), and osteocalcin (bone growth, support of insulin, and testosterone). Energy expenditure hormones are represented by cortisol (breakdown of liver glycogen/adipose tissue triglycerides/muscle protein, and gluconeogenesis; water retention), noradrenaline/adrenaline (breakdown of liver glycogen/adipose tissue triglycerides, and gluconeogenesis; water retention), growth hormone (glucogenic, lipolytic; has also growth-related aspects; water retention), thyroid gland hormones (increase metabolic effects of adrenaline/noradrenaline), and angiotensin II (induce insulin resistance and retain water). In chronic inflammatory diseases, a preponderance of energy expenditure pathways is switched on, leading to typical hormonal changes such as insulin/IGF-1 resistance, hypoandrogenemia, hypovitaminosis D, mild hypercortisolemia, and increased activity of the sympathetic nervous system and the renin-angiotensin-aldosterone system. Though necessary during acute inflammation in the context of systemic infection or trauma, these long-standing changes contribute to increased mortality in chronic

  7. Risk-Based Remediation Approach for Cs-137 Contaminated Sediment/Soils at the Savannah River Site (SRS) Lower Three Runs Tail (U) - 13348 - SRNS-RP-2012-00546

    SciTech Connect

    Freeman, Candice; Bergren, Christopher; Blas, Susan; Kupar, James

    2013-07-01

    .e., hunting, fishing, hiking etc.) and access from public property. Exposure of the adolescent trespasser to Cs-137 contaminated sediment/soil at concentrations greater than 23.7 pico curies per gram have been calculated to result in an unacceptable cancer risk (> 1 x 10{sup -4}). Comparing the characterization sampling results conducted in 2009 with the benchmark concentration of 23.7 pCi/g, identified elevated risk levels along three sampling areas in the Lower Three Runs tail portion. On January 5, 2012, it was agreed by the core team that a Removal Action in the Lower Three Runs tail was to be conducted for the identified soil/sediment locations in the three identified areas that exceed the 1 x 10{sup -4} risk (23.7 pCi/g) for the adolescent trespasser receptor. The addition of Land Use Controls following the Removal Action was appropriate to protect human health and the environment. A systematic screening matrix was initiated at the identified hot spots (i.e., sampling points with Cs-137 activities greater than 23.7 pCi/g) to identify the limits of the excavation area. Sediment/soil within the defined removal areas would be excavated to the depth necessary to achieve the cleanup goal and disposed of in a CERCLA Off-Site Rule approved disposal facility. It was agreed that this removal action would adequately reduce the volume of available Cs-137 in the Lower Three Runs tail and consequently residual activities of the Cs-137 would decay over time reducing the amount of Cs-137 available in the tail which would curtail risk. The Land Use Controls consist of installation of an additional seven miles of fencing at major road crossings, utility easements, and at areas that showed a higher probability of access. In addition, signs were placed along the entire SRS perimeter of the Lower Three Runs tail approximately every 200 feet. Sign posts included both a No Trespassing sign and a Contaminant Warning sign. The project initiated a subcontract for both the removal action and the

  8. Staff-Child Interactions: A Vygotskian Perspective. Accreditation and Beyond Series, Volume I.

    ERIC Educational Resources Information Center

    Fleer, Marilyn

    Taking a Vygotskian perspective, this monograph focuses on the quality of interaction between children and staff in Australian child care and education programs. Aspects of quality interaction are presented through examples of interaction and through personal stories of staff analyzing their interactional patterns through video and audiotapes.…

  9. Large-scale field study on thin-layer capping of marine PCDD/F-contaminated sediments in Grenlandfjords, Norway: physicochemical effects.

    PubMed

    Cornelissen, Gerard; Amstaetter, Katja; Hauge, Audun; Schaanning, Morten; Beylich, Bjørnar; Gunnarsson, Jonas S; Breedveld, Gijs D; Oen, Amy M P; Eek, Espen

    2012-11-01

    A large-scale field experiment on in situ thin-layer capping was carried out in the polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) contaminated Grenlandsfjords, Norway. The main focus of the trial was to test the effectiveness of active caps (targeted thickness of 2.5 cm) consisting of powdered activated carbon (AC) mixed into locally dredged clean clay. Nonactive caps (targed thickness of 5 cm) consisting of clay without AC as well as crushed limestone were also tested. Fields with areas of 10,000 to 40,000 m(2) were established at 30 to 100 m water depth. Auxiliary shaken laboratory batch experiments showed that 2% of the applied powdered AC substantially reduced PCDD/F porewater concentrations, by >90% for tetra-, penta- and hexa-clorinated congeners to 60-70% for octachlorinated ones. In-situ AC profiles revealed that the AC was mixed into the sediment to 3 to 5 cm depth in 20 months. Only around 25% of the AC was found inside the pilot fields. Sediment-to-water PCDD/F fluxes measured by in situ diffusion chambers were significantly lower at the capped fields than at reference fields in the same fjord, reductions being largest for the limestone (50-90%) followed by clay (50-70%), and the AC + clay (60%). Also reductions in overlying aqueous PCDD/F concentrations measured by passive samplers were significant in most cases (20-40% reduction), probably because of the large size of the trial fields. The AC was less effective in the field than in the laboratory, probably due to prolonged sediment-to-AC mass transfer times for PCDD/Fs and field factors such as integrity of the cap, new deposition of contaminated sediment particles, and bioturbation. The present field data indicate that slightly thicker layers of limestone and dredged clay can show as good physicochemical effectiveness as thin caps of AC mixed with clay, at least for PCDD/Fs during the first two years after cap placement. PMID:23046183

  10. The effect of phytostabilization on Zn speciation in a dredged contaminated sediment using scanning electron microscopy, X-ray fluorescence, EXAFS spectroscopy, and principal components analysis

    NASA Astrophysics Data System (ADS)

    Panfili, Frédéric; Manceau, Alain; Sarret, Géraldine; Spadini, Lorenzo; Kirpichtchikova, Tatiana; Bert, Valérie; Laboudigue, Agnès; Marcus, Matthew A.; Ahamdach, Noureddine; Libert, Marie-Françoise

    2005-05-01

    The maintenance of waterways generates large amounts of dredged sediments, which are deposited on adjacent land surfaces. These sediments are often rich in metal contaminants and present a risk to the local environment. Understanding how the metals are immobilized at the molecular level is critical for formulating effective metal containment strategies such as phytoremediation. In the present work, the mineralogical transformations of Zn-containing phases induced by two graminaceous plants (A grostis tenuis and Festuca rubra) in a contaminated sediment ([Zn] = 4700 mg kg -1, [P 2O 5] = 7000 mg kg -1, pH = 7.8), untreated or amended with hydroxylapatite (AP) or Thomas basic slag (TS), were investigated after two yr of pot experiment by scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS), synchrotron-based X-ray microfluorescence (μ-SXRF), and powder and laterally resolved extended X-ray absorption fine structure (μ-EXAFS) spectroscopy. The number and nature of Zn species were evaluated by principal component (PCA) and least-squares fitting (LSF) analysis of the entire set of μ-EXAFS spectra, which included up to 32 individual spectra from regions of interest varying in chemical composition. Seven Zn species were identified at the micrometer scale: sphalerite, gahnite, franklinite, Zn-containing ferrihydrite and phosphate, (Zn-Al)-hydrotalcite, and Zn-substituted kerolite-like trioctahedral phyllosilicate. Bulk fractions of each species were quantified by LSF of the powder EXAFS spectra to linear combinations of the identified Zn species spectra. In the untreated and unvegetated sediment, Zn was distributed as ˜50% (mole ratio of total Zn) sphalerite, ˜40% Zn-ferrihydrite, and ˜10 to 20% (Zn-Al)-hydrotalcite plus Zn-phyllosilicate. In unvegetated but amended sediments (AP and TS), ZnS and Zn-ferrihydrite each decreased by 10 to 20% and were replaced by Zn-phosphate (˜30˜40%). In the presence of plants, ZnS was almost completely

  11. High-volume image quality assessment systems: tuning performance with an interactive data visualization tool

    NASA Astrophysics Data System (ADS)

    Bresnahan, Patricia A.; Pukinskis, Madeleine; Wiggins, Michael

    1999-03-01

    Image quality assessment systems differ greatly with respect to the number and types of mags they need to evaluate, and their overall architectures. Managers of these systems, however, all need to be able to tune and evaluate system performance, requirements often overlooked or under-designed during project planning. Performance tuning tools allow users to define acceptable quality standards for image features and attributes by adjusting parameter settings. Performance analysis tools allow users to evaluate and/or predict how well a system performs in a given parameter state. While image assessment algorithms are becoming quite sophisticated, duplicating or surpassing the human decision making process in their speed and reliability, they often require a greater investment in 'training' or fine tuning of parameters in order to achieve optimum performance. This process may involve the analysis of hundreds or thousands of images, generating a large database of files and statistics that can be difficult to sort through and interpret. Compounding the difficulty is the fact that personnel charged with tuning and maintaining the production system may not have the statistical or analytical background required for the task. Meanwhile, hardware innovations have greatly increased the volume of images that can be handled in a given time frame, magnifying the consequences of running a production site with an inadequately tuned system. In this paper, some general requirements for a performance evaluation and tuning data visualization system are discussed. A custom engineered solution to the tuning and evaluation problem is then presented, developed within the context of a high volume image quality assessment, data entry, OCR, and image archival system. A key factor influencing the design of the system was the context-dependent definition of image quality, as perceived by a human interpreter. This led to the development of a five-level, hierarchical approach to image quality

  12. Propulsion and airframe aerodynamic interactions of supersonic V/STOL configurations. Volume 1: Wind tunnel test pressure data report

    NASA Technical Reports Server (NTRS)

    Zilz, D. E.; Devereaux, P. A.

    1985-01-01

    A wind tunnel model of a supersonic V/STOL fighter configuration has been tested to measure the aerodynamic interaction effects which can result from geometrically close-coupled propulsion system/airframe components. The approach was to configure the model to represent two different test techniques. One was a conventional test technique composed of two test modes. In the Flow-Through mode, absolute configuration aerodynamics are measured, including inlet/airframe interactions. In the Jet-Effects mode, incremental nozzle/airframe interactions are measured. The other test technique is a propulsion simulator approach, where a sub-scale, externally powered engine is mounted in the model. This allows proper measurement of inlet/airframe and nozzle/airframe interactions simultaneously. This is Volume 1 of 2: Wind Tunnel Test Pressure Data Report.

  13. Method of interactive specification of interested regions via a volume-rendered image with application to virtualized endoscope system

    NASA Astrophysics Data System (ADS)

    Mori, Kensaku; Higuchi, Yoshitake; Suenaga, Yasuhito; Toriwaki, Jun-ichiro; Hasegawa, Jun-ichi; Katada, Kazuhiro

    2000-04-01

    This paper proposes a method to specify interested regions including points, lines, surfaces and mass regions through a volume rendered image,directly and interactively, and its application to virtual endoscopy system. Measurement function is one of the most important functions in the virtual endoscopy. We should specify a target region on the virtual endoscopic image for measurements. It is hard to specify target regions on the organ wall in a volume rendered image, since the organ is not explicitly segmented from an input image when observed using the volume rendering. The proposed method enables the user to specify interested regions directly by analyzing change of accumulated opacity along a casting ray. When the user specify a point on a volume rendered image, we cast a ray that passes through a specified point of an image plane from a viewpoint. We considered the position that has the highest accumulated opacity as the three-dimensional position of the specified point. Line and surface regions are obtained by iterating the point specification method. A mass region is obtained by finding the interval on the ray where the opacity is greater than zero. We have implemented those specifying methods to our virtual endoscopy system. The result showed that we could specify points, lines, surfaces and mass regions on volume rendered images.

  14. Learning a Second Language through Interaction. Studies in Bilingualism, Volume 17.

    ERIC Educational Resources Information Center

    Ellis, Rod

    This book examines different theoretical perspectives on the role that interaction plays in second language acquisition. The principle perspectives are those provided by the Interaction Hypothesis, Socio-Cultural Theory, and the Levels of Processing Model. Interaction is defined broadly; it is seen as involving both intermental and intramental…

  15. A PC-based high-quality and interactive virtual endoscopy navigating system using 3D texture based volume rendering.

    PubMed

    Hwang, Jin-Woo; Lee, Jong-Min; Kim, In-Young; Song, In-Ho; Lee, Yong-Hee; Kim, SunI

    2003-05-01

    As an alternative method to optical endoscopy, visual quality and interactivity are crucial for virtual endoscopy. One solution is to use the 3D texture map based volume rendering method that offers high rendering speed without reducing visual quality. However, it is difficult to apply the method to virtual endoscopy. First, 3D texture mapping requires a high-end graphic workstation. Second, texture memory limits reduce the frame-rate. Third, lack of shading reduces visual quality significantly. As 3D texture mapping has become available on personal computers recently, we developed an interactive navigation system using 3D texture mapping on a personal computer. We divided the volume data into small cubes and tested whether the cubes had meaningful data. Only the cubes that passed the test were loaded into the texture memory and rendered. With the amount of data to be rendered minimized, rendering speed increased remarkably. We also improved visual quality by implementing full Phong shading based on the iso-surface shading method without sacrificing interactivity. With the developed navigation system, 256 x 256 x 256 sized brain MRA data was interactively explored with good image quality. PMID:12725966

  16. Orbiter subsystem hardware/software interaction analysis. Volume 8: AFT reaction control system, part 2

    NASA Technical Reports Server (NTRS)

    Becker, D. D.

    1980-01-01

    The orbiter subsystems and interfacing program elements which interact with the orbiter computer flight software are analyzed. The failure modes identified in the subsystem/element failure mode and effects analysis are examined. Potential interaction with the software is examined through an evaluation of the software requirements. The analysis is restricted to flight software requirements and excludes utility/checkout software. The results of the hardware/software interaction analysis for the forward reaction control system are presented.

  17. Orbiter subsystem hardware/software interaction analysis. Volume 8: Forward reaction control system

    NASA Technical Reports Server (NTRS)

    Becker, D. D.

    1980-01-01

    The results of the orbiter hardware/software interaction analysis for the AFT reaction control system are presented. The interaction between hardware failure modes and software are examined in order to identify associated issues and risks. All orbiter subsystems and interfacing program elements which interact with the orbiter computer flight software are analyzed. The failure modes identified in the subsystem/element failure mode and effects analysis are discussed.

  18. Verbal Interaction and Development in Families with Adolescents. Advances in Applied Developmental Psychology, Volume 15.

    ERIC Educational Resources Information Center

    Hofer, Manfred, Ed.; Youniss, James, Ed.; Noack, Peter, Ed.

    Individuation theory is rooted in the belief that it is a major developmental task for adolescents to establish their identity while simultaneously maintaining a relationship with their parents. Building on the individuation paradigm, the researchers contributing to this edited volume zeroed in on discourse as a critical mechanism through which…

  19. Discourse as Social Interaction. Discourse Studies: A Multidisciplinary Introduction. Volume 2.

    ERIC Educational Resources Information Center

    van Dijk, Teun A., Ed.

    The collection of essays on discourse as a form of social interaction includes: "Discourse as Interaction in Society" (Teun A. van Dijk); "Discourse Pragmatics" (Shoshana Blum-Kulka); "Conversation Analysis: An Approach to the Study of Social Action as Sense Making Practices" (Anita Pomerantz, B. J. Fehr); "Institutional Dialogue" (Paul Drew,…

  20. Interactions between the volume effects of hydroxyethyl starch 130/0.4 and Ringer´s acetate

    PubMed Central

    2013-01-01

    Introduction The turnover of Ringer´s solutions is greatly dependent on the physiological situation, such as the presence of dehydration or anaesthesia. The present study evaluates whether the kinetics is affected by previous infusion of colloid fluid. Methods Ten male volunteers with a mean age of 22 years underwent three infusion experiments, on separate days and in random order. The experiments included 10 mL/kg of 6% hydroxyethyl starch 130/0.4 (Voluven™), 20 mL/kg of Ringer's acetate, and a combination of both, where Ringer´s was administered 75 minutes after the starch infusion ended. The kinetics of the volume expansion was analysed by non-linear least- squares regression, based on urinary excretion and serial measurement of blood haemoglobin concentration for up to 420 minutes. Results The mean volume of distribution of the starch was 3.12 L which agreed well with the plasma volume (3.14 L) estimated by anthropometry. The volume expansion following the infusion of starch showed monoexponential elimination kinetics with a half-life of two hours. Two interaction effects were found when Ringer´s acetate was infused after the starch. First, there was a higher tendency for Ringer´s acetate to distribute to a peripheral compartment at the expense of the plasma volume expansion. The translocated amount of Ringer´s was 70% higher when HES had been infused earlier. Second, the elimination half-life of Ringer´s acetate was five times longer when administered after the starch (88 versus 497 minutes, P <0.02). Conclusions Starch promoted peripheral accumulation of the later infused Ringer´s acetate solution and markedly prolonged the elimination half-life. Trial registration ClinicalTrials.gov: NCT01195025 PMID:23718743

  1. Interaction of airborne and structureborne noise radiated by plates. Volume 2: Experimental study

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The interaction of airborne and structureborne noise radiated by aircaraft materials was studied. The results corroborate the findings of an earlier analytical study by showing that the noise radiation of vibrating plates due to combined airborne and structureborne inputs possesses a stong synergistic nature. The large influence of the interaction between the airborne and structureborne inputs was hitherto ignored by researchers of aircraft interior noise problems.

  2. Interactive high-quality visualization of color volume datasets using GPU-based refinements of segmentation data.

    PubMed

    Lee, Byeonghun; Kwon, Koojoo; Shin, Byeong-Seok

    2016-04-24

    Data sets containing colored anatomical images of the human body, such as Visible Human or Visible Korean, show realistic internal organ structures. However, imperfect segmentations of these color images, which are typically generated manually or semi-automatically, produces poor-quality rendering results. We propose an interactive high-quality visualization method using GPU-based refinements to aid in the study of anatomical structures. In order to represent the boundaries of a region-of-interest (ROI) smoothly, we apply Gaussian filtering to the opacity values of the color volume. Morphological grayscale erosion operations are performed to reduce the region size, which is expanded by Gaussian filtering. Pseudo-coloring and color blending are also applied to the color volume in order to give more informative rendering results. We implement these operations on GPUs to speed up the refinements. As a result, our method delivered high-quality result images with smooth boundaries and provided considerably faster refinements. The speed of these refinements is sufficient to be used with interactive renderings as the ROI changes, especially compared to CPU-based methods. Moreover, the pseudo-coloring methods used presented anatomical structures clearly. PMID:27127935

  3. Interactive Videodisc: the "Why" and the "How." CALICO Monograph Volume 2, Spring 1991.

    ERIC Educational Resources Information Center

    Bush, Michael D.; And Others

    This monograph presents articles on interactive videodisc technology in language learning, ranging from the importance of a theoretical framework, the transition from theory to practice, getting started, design considerations, hypermedia, discovery environments, authoring software, workstation environments, and a look at the future of optical disc…

  4. Map It: Tools for Charting the Vast Territories of Your Mind. Interactive Comics Volume 1.

    ERIC Educational Resources Information Center

    Margulies, Nancy

    Teachers and students are continuously searching for fun and easy ways to help students organize and enhance their thoughts. This document uses interactive comics to describe the process of mind mapping to aid learners in developing new and creative ideas. The document also includes a brief overview of the functions of the brain's right and left…

  5. Researching Online Foreign Language Interaction and Exchange: Theories, Methods and Challenges. Telecollaboration in Education. Volume 3

    ERIC Educational Resources Information Center

    Dooly, Melinda; O'Dowd, Robert

    2012-01-01

    This book provides an accessible introduction to some of the methods and theoretical approaches for investigating foreign language (FL) interaction and exchange in online environments. Research approaches which can be applied to Computer-Mediated Communication (CMC) are outlined, followed by discussion of the way in which tools and techniques for…

  6. Coupled 2-dimensional cascade theory for noise an d unsteady aerodynamics of blade row interaction in turbofans. Volume 2: Documentation for computer code CUP2D

    NASA Technical Reports Server (NTRS)

    Hanson, Donald B.

    1994-01-01

    A two dimensional linear aeroacoustic theory for rotor/stator interaction with unsteady coupling was derived and explored in Volume 1 of this report. Computer program CUP2D has been written in FORTRAN embodying the theoretical equations. This volume (Volume 2) describes the structure of the code, installation and running, preparation of the input file, and interpretation of the output. A sample case is provided with printouts of the input and output. The source code is included with comments linking it closely to the theoretical equations in Volume 1.

  7. Formation and Assembly-Disassembly Processes of ZnO Hexagonal Pyramids Driven by Dipolar and Excluded Volume Interactions

    SciTech Connect

    Yang, Ming; Sun, Kai; Kotov, Nicholas A.

    2010-01-20

    ZnO hexagonal pyramids were obtained in hydrophilic media without any traditional stabilizers (capping agents). The absence of a thick organic shell reducing the anisotropy of nanoparticle (NP) interactions, oxide nature of the materials, and new geometry of the nanocrystals makes possible the observation of new self-organization phenomena. Several new features not present in the previous cases of NP self-organization were identified and discussed. The formation of ZnO pyramids involved recrystallization of larger amorphous NPs followed by the multistage disassembly of intermediate aggregates into individual virtually perfectly shaped nanocrystals. The evolution of NPs begins with crystallization of clustered plates within the original amorphous spherical colloids, and then agglomerated truncated pyramids are formed. These agglomerates further transform into chained pyramids, which eventually separate from each other. The crystallization and disassembly processes can be associated with the decrease of potential and anisotropy of the attractive force field around the crystallites represented in part by dipole moments. The reassembly of the pyramids can still be attained via engaging excluded volume interaction after adding similarly charged polymer. Overall, in this system, we see the first examples of (1) coupled crystallization and disassembly process; (2) induced assembly of nanoscale particles using excluded volume interactions, which were previously used only for aggregation of microscale colloids; and (3) nanoparticle assemblies with variable and experimentally verifiable relative orientation of dipoles including head-to-tail, tail-to-tail pairs, and antiparallel chains. Described assemblies of ZnO pyramids with collective behavior of individual building blocks as well as distinct and experimentally controlled stages of assembly and disassembly present a fundamentally interesting nanoparticle system with rich dynamic behavior.

  8. A digital computer program for the dynamic interaction simulation of controls and structure (DISCOS), volume 1

    NASA Technical Reports Server (NTRS)

    Bodley, C. S.; Devers, A. D.; Park, A. C.; Frisch, H. P.

    1978-01-01

    A theoretical development and associated digital computer program system for the dynamic simulation and stability analysis of passive and actively controlled spacecraft are presented. The dynamic system (spacecraft) is modeled as an assembly of rigid and/or flexible bodies not necessarily in a topological tree configuration. The computer program system is used to investigate total system dynamic characteristics, including interaction effects between rigid and/or flexible bodies, control systems, and a wide range of environmental loadings. In addition, the program system is used for designing attitude control systems and for evaluating total dynamic system performance, including time domain response and frequency domain stability analyses.

  9. Interactions between energy supply and transportation-related energy use, volume 1

    NASA Astrophysics Data System (ADS)

    Adler, T. J.; Ison, J. W.; Geinzer, J. C.

    1980-01-01

    The structure of ENTRANS and some of its policy analysis applications are described. ENTRANS is a computer simulator model of the interactions between energy supply and transportation related energy use. It includes a complete representation of the characteristics of transportation supply (public transit, carpooling, highways, and autos) and of households' travel related decisions (car type, travel mode, trip length, and frequency choices). The model is capable of analyzing a wide range of policies designed to change automobile fuel use. The results of several detailed policy analyses are described.

  10. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 1: User's manual

    NASA Technical Reports Server (NTRS)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The user's manual for the rocket combustor interactive design (ROCCID) computer program is presented. The program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial, and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can easily be added. The analysis model in ROCCID can account for the influence of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  11. Interaction of airborne and structureborne noise radiated by plates. Volume 1: Analytical study

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The interaction of airborne and structureborne noise radiated by aircraft materials was examined. The theory and results of several computer simulations of the noise radiated by thin, isotropic, rectangular aluminum plates due to fully coherent combined acoustic and vibrational inputs is presented. The most significant finding was the extremely large influence that the relative phase between inputs has on the combined noise radiation of the plates. Phase dependent effects manifest themselves as cross terms in both the dynamic and acoustic portions of the analysis. Computer simulations show that these cross terms can radically alter the combined sound power radiated by plates constructed of aircraft-type materials. The results suggest that airborne-structureborne interactive effects could be responsible for a significant portion of the overall noise radiated by aircraft-type structures in the low frequency regime. This implies that previous analytical and experimental studies may have neglected an important physical phenomenon in the analayses of the interior noise of propeller dirven aircraft.

  12. Study of interaction between solar arrays and attitude - orbit control. Volume 1: Technical Report

    NASA Astrophysics Data System (ADS)

    Annett, R. J.

    1980-04-01

    Interface criteria for the specification of solar arrays and attitude control systems for given mission profiles were defined for an Earth observation satellite, a high accuracy, heavy pointing platform and a heavy, geostationary, communications satellite. A double roll-out, a hybrid and an ultra-lightweight panel array were chosen with power levels varying from 1 1/4 kW to 3 kW per wing. Mathematical techniques were developed to modify the array modal data to enable the array design to be performed independently of the center body and general system parameters. The dynamic interaction between the array flexure and various controller algorithms was examined by analytical and simulation techniques and the limits of applicability of specific algorithms are defined. The impact of these modal parameter boundaries are re-evaluated in terms of allowable domains for the dominant structural parameters. Allowable array configurations are shown for given controller algorithms for specific mission senarios.

  13. Energy characteristics of beam-plasma interaction in a closed volume

    NASA Astrophysics Data System (ADS)

    Klykov, I. L.; Tarakanov, V. P.; Shustin, E. G.

    2012-03-01

    Energy exchange between an electron beam and plasma during a beam-plasma discharge in a closed cavity excited by the electron beam is analyzed using computer simulations by the KARAT code. A method allowing one to analyze the beam-plasma interaction in the quasi-steady stage of the discharge is proposed. Qualitative characteristics of energy exchange (such as beam energy losses and the energy distributions of beam electrons and plasma particles leaving the discharge) both during spontaneous discharge excitation and in the presence of initial beam modulation by regular or noiselike signals are determined. The results obtained enable one to estimate the energy characteristics of a plasma processing reactor based on a beam-plasma discharge.

  14. Application of Molecular Interaction Volume Model for Phase Equilibrium of Sn-Based Binary System in Vacuum Distillation

    NASA Astrophysics Data System (ADS)

    Kong, Lingxin; Yang, Bin; Xu, Baoqiang; Li, Yifu

    2014-09-01

    Based on the molecular interaction volume model (MIVM), the activities of components of Sn-Sb, Sb-Bi, Sn-Zn, Sn-Cu, and Sn-Ag alloys were predicted. The predicted values are in good agreement with the experimental data, which indicate that the MIVM is of better stability and reliability due to its good physical basis. A significant advantage of the MIVM lies in its ability to predict the thermodynamic properties of liquid alloys using only two parameters. The phase equilibria of Sn-Sb and Sn-Bi alloys were calculated based on the properties of pure components and the activity coefficients, which indicates that Sn-Sb and Sn-Bi alloys can be separated thoroughly by vacuum distillation. This study extends previous investigations and provides an effective and convenient model on which to base refining simulations for Sn-based alloys.

  15. Interaction of a laminar flame with its self-generated flow during constant volume combustion

    SciTech Connect

    Dunn-Rankin, D.; Sawyer, R.F.

    1985-02-01

    The formation of cusp shaped or ''tulip'' flames during closed tube flame propagation has been recorded by combustion researchers for nearly sixty years. Flame instability, pressure wave/flame interaction, and large scale circulation in the unburned gas have been suggested as explanations for the ''tulip'' flame phenomenon, but the cause of the ''tulip'' flame has not been conclusively determined. This work uses laser Doppler anemometer measurements of the flow field during flame propagation in a closed tube to describe the combustion generated flow and to support a fluid mechanical explanation for the ''tulip'' flame formation. The flame behaves as a fluid mechanical discontinuity which deflects the velocity of the gas passing through it. As the flame quenches at the side walls of the combustion vessel, the flow deflection generates a vortex in the burned gas. The vortex remains in the proximity of the flame and modifies the unburned gas field such that the flame propagates more quickly near the wall than at the center. The discrepancy in propagation rates leads to the ''tulip'' flame.

  16. Effects of food concentration, animal interactions, and water volume on survival, growth, and reproduction of daphnia magna under flow-through conditions

    SciTech Connect

    LeBlanc, G.A.; Schoenfeld, D.A.; Surpreant, D.C.

    1981-10-01

    The purpose of this study is to evaluate the effects of food concentration, animal interaction, and water volume on the survival, growth, and reproduction of Daphnia magna under flow-through conditions. A response surface design was used to determine the interactive, as well as the individual, effects of the three factors. The results indicated that there were no important interactive effects of the three factors on survival, growth, or reproduction of D. magna. Individual effects of the factors on reproduction were observed. Food concentration produced a linear trend, with increasing food concentration resulting in an increase in offspring production. The number of daphnids per container produced a quadratic trend, with the maximum offspring production occurring in vessels containing approximately 14 daphnids. Water volume produced a slight linear trend, with increasing water volume resulting in an increase in offspring production.

  17. Branched conformational properties of macromolecules in close relation to chemical synthesis. II. Influence of excluded volume interactions.

    PubMed

    Burchard, Walther; Schweins, Ralf; Werner, Marcel

    2015-09-21

    The description of perturbed particle conformations needs as a prerequisite the algorithm of unperturbed chains which is outlined in Paper I [J. Chem. Phys. 143, 114906 (2015)]. The mean square segment length ⟨r(2)(n)⟩=b(2)n(2ν) with ν = 0.588 for linear chains in a good solvent is used as an approximation also for branched samples. The mean square radius of gyration is easily derived, but for the hydrodynamic, the segment distribution by Domb et al. [Proc. Phys. Soc., London 85, 624 (1965)] is required. Both radii can analytically be expressed by Gamma functions. For the angular dependence of scattered light, the Fourier transform of the Domb distribution for self-avoiding random walk is needed, which cannot be obtained as an analytical function and was derived by numerical integration. The summation over all segment length in the particle was performed with an analytic fit-curve for the Fourier transform and was carried out numerically. Results were derived (i) for uniform and polydisperse linear chains, (ii) or f-functional randomly branched polymers and their monodisperse fractions, (iii) for random A3B2 co-polymers, and (iv) for AB2 hyper-branched samples. The deviation of the Gaussian approximation with the variance of ⟨r(2)(n)⟩=b(2)n(2ν) slightly overestimates the excluded volume interaction but still remains a fairly good approximation for region of qR(g) < 10. PMID:26395738

  18. Control volume analyses of glottal flow using a fully-coupled numerical fluid-structure interaction model

    NASA Astrophysics Data System (ADS)

    Yang, Jubiao; Krane, Michael; Zhang, Lucy

    2013-11-01

    Vocal fold vibrations and the glottal jet are successfully simulated using the modified Immersed Finite Element method (mIFEM), a fully coupled dynamics approach to model fluid-structure interactions. A self-sustained and steady vocal fold vibration is captured given a constant pressure input at the glottal entrance. The flow rates at different axial locations in the glottis are calculated, showing small variations among them due to the vocal fold motion and deformation. To further facilitate the understanding of the phonation process, two control volume analyses, specifically with Bernoulli's equation and Newton's 2nd law, are carried out for the glottal flow based on the simulation results. A generalized Bernoulli's equation is derived to interpret the correlations between the velocity and pressure temporally and spatially along the center line which is a streamline using a half-space model with symmetry boundary condition. A specialized Newton's 2nd law equation is developed and divided into terms to help understand the driving mechanism of the glottal flow.

  19. Branched conformational properties of macromolecules in close relation to chemical synthesis. II. Influence of excluded volume interactions

    NASA Astrophysics Data System (ADS)

    Burchard, Walther; Schweins, Ralf; Werner, Marcel

    2015-09-01

    The description of perturbed particle conformations needs as a prerequisite the algorithm of unperturbed chains which is outlined in Paper I [J. Chem. Phys. 143, 114906 (2015)]. The mean square segment length = b 2 n 2 ν with ν = 0.588 for linear chains in a good solvent is used as an approximation also for branched samples. The mean square radius of gyration is easily derived, but for the hydrodynamic, the segment distribution by Domb et al. [Proc. Phys. Soc., London 85, 624 (1965)] is required. Both radii can analytically be expressed by Gamma functions. For the angular dependence of scattered light, the Fourier transform of the Domb distribution for self-avoiding random walk is needed, which cannot be obtained as an analytical function and was derived by numerical integration. The summation over all segment length in the particle was performed with an analytic fit-curve for the Fourier transform and was carried out numerically. Results were derived (i) for uniform and polydisperse linear chains, (ii) or f-functional randomly branched polymers and their monodisperse fractions, (iii) for random A3B2 co-polymers, and (iv) for AB2 hyper-branched samples. The deviation of the Gaussian approximation with the variance of = b 2 n 2 ν slightly overestimates the excluded volume interaction but still remains a fairly good approximation for region of qRg < 10.

  20. Fast interactive real-time volume rendering of real-time three-dimensional echocardiography: an implementation for low-end computers

    NASA Technical Reports Server (NTRS)

    Saracino, G.; Greenberg, N. L.; Shiota, T.; Corsi, C.; Lamberti, C.; Thomas, J. D.

    2002-01-01

    Real-time three-dimensional echocardiography (RT3DE) is an innovative cardiac imaging modality. However, partly due to lack of user-friendly software, RT3DE has not been widely accepted as a clinical tool. The object of this study was to develop and implement a fast and interactive volume renderer of RT3DE datasets designed for a clinical environment where speed and simplicity are not secondary to accuracy. Thirty-six patients (20 regurgitation, 8 normal, 8 cardiomyopathy) were imaged using RT3DE. Using our newly developed software, all 3D data sets were rendered in real-time throughout the cardiac cycle and assessment of cardiac function and pathology was performed for each case. The real-time interactive volume visualization system is user friendly and instantly provides consistent and reliable 3D images without expensive workstations or dedicated hardware. We believe that this novel tool can be used clinically for dynamic visualization of cardiac anatomy.

  1. Effect of PEG Grafting Density and Hydrodynamic Volume on Gold Nanoparticle-Cell Interactions: An Investigation on Cell Cycle, Apoptosis, and DNA Damage.

    PubMed

    Uz, Metin; Bulmus, Volga; Alsoy Altinkaya, Sacide

    2016-06-14

    In this study, interactions of polyethylene glycol (PEG)-coated gold nanoparticles (AuNPs) with cells were investigated with particular focus on the relationship between the PEG layer properties (conformation, grafting density, and hydrodynamic volume) and cell cycle arrest, apoptosis, and DNA damage. Steric hindrance and PEG hydrodynamic volume controlled the protein adsorption, whereas the AuNP core size and PEG hydrodynamic volume were primary factors for cell uptake and viability. At all PEG grafting densities, the particles caused significant cell cycle arrest and DNA damage against CaCo2 and PC3 cells without apoptosis. However, at a particular PEG grafting density (∼0.65 chains/nm(2)), none of these severe damages were observed on 3T3 cells indicating discriminating behavior of the healthy (3T3) and cancer (PC3 and CaCo2) cells. It was concluded that the PEG grafting density and hydrodynamic volume, tuned with the PEG concentration and AuNP size, played an important role in particle-cell interactions. PMID:27206138

  2. Propulsion and airframe aerodynamic interactions of supersonic V/STOL configurations. Volume 2: Wind tunnel test force and moment data report

    NASA Technical Reports Server (NTRS)

    Zilz, D. E.

    1985-01-01

    A wind tunnel model of a supersonic V/STOL fighter configuration has been tested to measure the aerodynamic interaction effects which can result from geometrically close-coupled propulsion system/airframe components. The approach was to configure the model to represent two different test techniques. One was a conventional test technique composed of two test modes. In the Flow-Through mode, absolute configuration aerodynamics are measured, including inlet/airframe interactions. In the Jet-Effects mode, incremental nozzle/airframe interactions are measured. The other test technique is a propulsion simulator approach, where a sub-scale, externally powered engine is mounted in the model. This allows proper measurement of inlet/airframe and nozzle/airframe interactions simultaneously. This is Volume 2 of 2: Wind Tunnel Test Force and Moment Data Report.

  3. To what extent do long-duration high-volume dam releases influence river-aquifer interactions? A case study in New South Wales, Australia

    NASA Astrophysics Data System (ADS)

    Graham, P. W.; Andersen, M. S.; McCabe, M. F.; Ajami, H.; Baker, A.; Acworth, I.

    2015-03-01

    Long-duration high-volume dam releases are unique anthropogenic events with no naturally occurring equivalents. The impact from such dam releases on a downstream Quaternary alluvial aquifer in New South Wales, Australia, is assessed. It is observed that long-duration (>26 days), high-volume dam releases (>8,000 ML/day average) result in significant variations in river-aquifer interactions. These variations include a flux from the river to the aquifer up to 6.3 m3/day per metre of bank (at distances of up to 330 m from the river bank), increased extent and volume of recharge/bank storage, and a long-term (>100 days) reversal of river-aquifer fluxes. In contrast, during lower-volume events (<2,000 ML/day average) the flux was directed from the aquifer to the river at rates of up to 1.6 m3/day per metre of bank. A groundwater-head prediction model was constructed and river-aquifer fluxes were calculated; however, predicted fluxes from this method showed poor correlation to fluxes calculated using actual groundwater heads. Long-duration high-volume dam releases have the potential to skew estimates of long-term aquifer resources and detrimentally alter the chemical and physical properties of phreatic aquifers flanking the river. The findings have ramifications for improved integrated management of dam systems and downstream aquifers.

  4. Transcriptional responses in juvenile Atlantic cod (Gadus morhua) after exposure to mercury-contaminated sediments obtained near the wreck of the German WW2 submarine U-864, and from Bergen Harbor, Western Norway.

    PubMed

    Olsvik, Pål A; Brattås, Marianne; Lie, Kai K; Goksøyr, Anders

    2011-04-01

    The main aim of the present work was to investigate the effects of mercury (Hg)-enriched sediments on fish. Sediments near the sunken German WW2 submarine U-864, which according to historical documents included 67 tons of metallic Hg in its cargo, are enriched of Hg leaking from the wreckage. Juvenile Atlantic cod (Gadus morhua) were exposed to two field-collected polluted sediments (U-864: inorganic Hg and Bergen Harbor (Vågen): inorganic Hg, PCB and PAH) or two comparable reference sediments for 5 weeks in the laboratory, and transcriptional responses evaluated in gills and liver. Gills of fish exposed to the Hg-enriched sunken WW2 submarine U-864 sediment contained four fold higher Hg levels compared to the control fish. An increase in Hg content in liver in the U-864 fish was also observed. The transcriptional results showed that calreticulin, HSP70 and heme oxygenase mRNA were significantly up-regulated in gills in fish exposed to the Hg-enriched sediments, whereas calreticulin, heme oxygenase, transferrin and WAP65 were significantly up-regulated and glutathione peroxidase 4B and zona pellucida 3 were significantly down-regulated in liver tissue. In gills and liver of cod exposed to the mixed-contaminated Vågen sediment, CYP1A showed the highest induction. In conclusion, the experiment shows that sediment-bound Hg is available to the fish and affects the transcription of oxidative stress responsive enzymes, suggesting that the Hg-enriched sediments may negatively affect the local wildlife. Furthermore, the mixed contaminated sediments of Vågen affected similar responses in addition to Ah-receptor mediated responses reflecting exposure to PAHs and PCBs. PMID:21195448

  5. Modeling Aeolian Transport of Contaminated Sediments at Los Alamos National Laboratory, Technical Area 54, Area G: Sensitivities to Succession, Disturbance, and Future Climate

    SciTech Connect

    Whicker, Jeffrey J.; Kirchner, Thomas B.; Breshears, David D.; Field, Jason P.

    2012-03-27

    The Technical Area 54 (TA-54) Area G disposal facility is used for the disposal of radioactive waste at Los Alamos National Laboratory (LANL). U.S. Department of Energy (DOE) Order 435.1 (DOE, 2001) requires that radioactive waste be managed in a manner that protects public health and safety and the environment. In compliance with that requirement, DOE field sites must prepare and maintain site-specific radiological performance assessments for facilities that receive waste after September 26, 1988. Sites are also required to conduct composite analyses for facilities that receive waste after this date; these analyses account for the cumulative impacts of all waste that has been (and will be) disposed of at the facilities and other sources of radioactive material that may interact with these facilities. LANL issued Revision 4 of the Area G performance assessment and composite analysis in 2008. In support of those analyses, vertical and horizontal sediment flux data were collected at two analog sites, each with different dominant vegetation characteristics, and used to estimate rates of vertical resuspension and wind erosion for Area G. The results of that investigation indicated that there was no net loss of soil at the disposal site due to wind erosion, and suggested minimal impacts of wind on the long-term performance of the facility. However, that study did not evaluate the potential for contaminant transport caused by the horizontal movement of soil particles over long time frames. Since that time, additional field data have been collected to estimate wind threshold velocities for initiating sediment transport due to saltation and rates of sediment transport once those thresholds are reached. Data such as these have been used in the development of the Vegetation Modified Transport (VMTran) model. This model is designed to estimate patterns and long-term rates of contaminant redistribution caused by winds at the site, taking into account the impacts of plant

  6. The remediation of heavy metals contaminated sediment.

    PubMed

    Peng, Jian-Feng; Song, Yong-Hui; Yuan, Peng; Cui, Xiao-Yu; Qiu, Guang-Lei

    2009-01-30

    Heavy metal contamination has become a worldwide problem through disturbing the normal functions of rivers and lakes. Sediment, as the largest storage and resources of heavy metal, plays a rather important role in metal transformations. This paper provides a review on the geochemical forms, affecting factors and remediation technologies of heavy metal in sediment. The in situ remediation of sediment aims at increasing the stabilization of some metals such as the mobile and the exchangeable fractions; whereas, the ex situ remediation mainly aims at removing those potentially mobile metals, such as the Mn-oxides and the organic matter (OM) fraction. The pH and OM can directly change metals distribution in sediment; however oxidation-reduction potential (ORP), mainly through changing the pH values, indirectly alters metals distribution. Mainly ascribed to their simple operation mode, low costs and fast remediation effects, in situ remediation technologies, especially being fit for slight pollution sediment, are applied widely. However, for avoiding metal secondary pollution from sediment release, ex situ remediation should be the hot point in future research. PMID:18547718

  7. CONTAMINATED SEDIMENT SCREENING LEVELS FOR SUPERFUND SITES

    EPA Science Inventory

    Sediments serve as the dominant sink for many chemical pollutants, in particular those which are highly hydrophobic and have a greater tendency to bioaccumulate in aquatic food webs. A variety of toxicological benchmarks and laboratory bioassays have been developed for assessing...

  8. CONTAMINATED SEDIMENT TRANSPORT AND FATE MODELING

    EPA Science Inventory

    Many Superfund sites include rivers, reservoirs, and other surface bodies of water (and the adjacent floodplains) that are highly contaminated with PCBs, metals, and other toxic chemicals. Examples of contaminated waters are the Hudson, Fox, Housatonic and Clark Fork Rivers, Lake...

  9. SIGI: Field Test and Evaluation of a Computer-Based System of Interactive Guidance and Information. Volume I: Report.

    ERIC Educational Resources Information Center

    Chapman, Warren; And Others

    The computer-based System of Interactive Guidance and Information (SIGI) was field tested and evaluated at five community colleges and one university. Developed by Educational Testing Service, SIGI assists students in the process of informed and rational career decision making. Interacting at a cathode-ray tube terminal with a computer, students…

  10. Evaluation of reduced sediment volume procedures for acute toxicity tests using the estuarine amphipod Leptocheirus plumulosus.

    PubMed

    Stanley, Jacob K; Kennedy, Alan J; Farrar, J Daniel; Mount, David R; Steevens, Jeffery A

    2010-12-01

    The volume of sediment required to perform a sediment toxicity bioassay is a major driver of the overall cost associated with that bioassay. Sediment volume affects bioassay cost because of sediment collection, transportation, storage, and disposal costs as well as labor costs associated with organism recovery at the conclusion of the exposure. The objective of the current study was to evaluate reduced sediment volume versions of the standard U.S. Environmental Protection Agency (U.S. EPA) 10-d acute Leptocheirus plumulosus method that uses a beaker size of 1,000 ml and 20 organisms. The test design used evaluated the effects of beaker size (250 and 100 ml) and associated sediment volume (75 and 30 ml, respectively) as well as organism loading density (10 and 20 organisms) on test endpoint responsiveness relative to the standard 10-d test method. These comparisons were completed with three different types of contaminated sediments: a field-collected polycyclic aromatic hydrocarbon (PAH)-contaminated sediment, a lead-spiked control sediment, and a control sediment spiked with mineral oil. Assessment criteria included test endpoint sensitivity, endpoint consistency, statistical power, water quality, and logistical assessments. Results indicate that the current U.S. EPA method is preferable to the reduced sediment volume methods we assessed, but that a 250-ml beaker/10 organism experimental design is of comparable utility and may be advantageous when reduced sediment volumes are desirable because of high contaminant (spiking studies) or sediment disposal costs. In addition, the results of the current study provide toxicity reference values for PAHs, lead, and an oil surrogate for petroleum hydrocarbons. PMID:20890914

  11. Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 1: Executive summary and overview

    NASA Technical Reports Server (NTRS)

    Fogleman, Guy (Editor); Huntington, Judith L. (Editor); Schwartz, Deborah E. (Editor); Fonda, Mark L. (Editor)

    1989-01-01

    An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. The first volume includes the executive summary, overview, scientific justification, history, and planned development of the Facility.

  12. Flow structure generated by perpendicular blade-vortex interaction and implications for helicopter noise prediction. Volume 1: Measurements

    NASA Technical Reports Server (NTRS)

    Wittmer, Kenneth S.; Devenport, William J.

    1996-01-01

    The perpendicular interaction of a streamwise vortex with an infinite span helicopter blade was modeled experimentally in incompressible flow. Three-component velocity and turbulence measurements were made using a sub-miniature four sensor hot-wire probe. Vortex core parameters (radius, peak tangential velocity, circulation, and centerline axial velocity deficit) were determined as functions of blade-vortex separation, streamwise position, blade angle of attack, vortex strength, and vortex size. The downstream development of the flow shows that the interaction of the vortex with the blade wake is the primary cause of the changes in the core parameters. The blade sheds negative vorticity into its wake as a result of the induced angle of attack generated by the passing vortex. Instability in the vortex core due to its interaction with this negative vorticity region appears to be the catalyst for the magnification of the size and intensity of the turbulent flowfield downstream of the interaction. In general, the core radius increases while peak tangential velocity decreases with the effect being greater for smaller separations. These effects are largely independent of blade angle of attack; and if these parameters are normalized on their undisturbed values, then the effects of the vortex strength appear much weaker. Two theoretical models were developed to aid in extending the results to other flow conditions. An empirical model was developed for core parameter prediction which has some rudimentary physical basis, implying usefulness beyond a simple curve fit. An inviscid flow model was also created to estimate the vorticity shed by the interaction blade, and to predict the early stages of its incorporation into the interacting vortex.

  13. Effect of Alzheimer's Disease Risk Variant rs3824968 at SORL1 on Regional Gray Matter Volume and Age-Related Interaction in Adult Lifespan

    PubMed Central

    Huang, Chu-Chung; Liu, Mu-En; Kao, Hung-Wen; Chou, Kun-Hsien; Yang, Albert C.; Wang, Ying-Hsiu; Chen, Tong-Ru; Tsai, Shih-Jen; Lin, Ching-Po

    2016-01-01

    Sortilin receptor 1 (SORL1) is involved in cellular trafficking of amyloid precursor protein and plays an essential role in amyloid-beta peptide generation in Alzheimer disease (AD). The major A allele in a SORL1 single nucleotide polymorphism (SNP), rs3824968, is associated with an increased AD risk. However, the role of SORL1 rs3824968 in the normal ageing process has rarely been examined in relation to brain structural morphology. This study investigated the association between SORL1 rs3824968 and grey matter (GM) volume in a nondemented Chinese population of 318 adults within a wide age range (21–92 years). Through voxel-based morphometry, we found that participants carrying SORL1 allele A exhibited significantly smaller GM volumes in the right posterior cingulate, left middle occipital, medial frontal, and superior temporal gyri. Considerable interaction between age and SORL1 suggested a detrimental and accelerated ageing effect of allele A on putamen. These findings provide evidence that SORL1 rs3824968 modulates regional GM volume and is associated with brain trajectory during the adult lifespan. PMID:26996954

  14. LOCA hydroloads calculations with multidimensional nonlinear fluid/structure interaction. Volume 3. Fluid/structure interaction studies using 3-D STEALTH/WHAMSE. Final report. [PWR

    SciTech Connect

    Santee, G.E. Jr.; Chang, F.H.; Mortensen, G.A.; Brockett, G.F.; Gross, M.B.; Belytschko, T.B.

    1982-11-01

    This report, the third in a series of reports for RP-1065, describes the final step in the stepwise approach for developing the three-dimensional, nonlinear, fluid-structure interaction methodology to assess the hydroloads on a large PWR during the subcooled portions of a hypothetical LOCA. The final step in the methodology implements enhancements and special modifications to the STEALTH 3D computer program and the WHAMSE 3D computer program. After describing the enhancements, the individual and the coupled computer programs are assessed by comparing calculational results with either analytical solutions or with experimental data. The coupled 3D STEALTH/WHAMSE computer program is then applied to the simulation of HDR Test V31.1 to further assess the program and to investigate the role that fluid-structure interaction plays in the hydrodynamic loading of reactor internals during subcooled blowdown.

  15. Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

    NASA Technical Reports Server (NTRS)

    Fogleman, Guy (Editor); Huntington, Judith L. (Editor); Schwartz, Deborah E. (Editor); Fonda, Mark L. (Editor)

    1989-01-01

    An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress.

  16. Self-consistent field theory of tethered polymers: One dimensional, three dimensional, strong stretching theories and the effects of excluded-volume-only interactions

    SciTech Connect

    Suo, Tongchuan Whitmore, Mark D.

    2014-11-28

    We examine end-tethered polymers in good solvents, using one- and three-dimensional self-consistent field theory, and strong stretching theories. We also discuss different tethering scenarios, namely, mobile tethers, fixed but random ones, and fixed but ordered ones, and the effects and important limitations of including only binary interactions (excluded volume terms). We find that there is a “mushroom” regime in which the layer thickness is independent of the tethering density, σ, for systems with ordered tethers, but we argue that there is no such plateau for mobile or disordered anchors, nor is there one in the 1D theory. In the other limit of brushes, all approaches predict that the layer thickness scales linearly with N. However, the σ{sup 1/3} scaling is a result of keeping only excluded volume interactions: when the full potential is included, the dependence is faster and more complicated than σ{sup 1/3}. In fact, there does not appear to be any regime in which the layer thickness scales in the combination Nσ{sup 1/3}. We also compare the results for two different solvents with each other, and with earlier Θ solvent results.

  17. Self-consistent field theory of tethered polymers: One dimensional, three dimensional, strong stretching theories and the effects of excluded-volume-only interactions

    NASA Astrophysics Data System (ADS)

    Suo, Tongchuan; Whitmore, Mark D.

    2014-11-01

    We examine end-tethered polymers in good solvents, using one- and three-dimensional self-consistent field theory, and strong stretching theories. We also discuss different tethering scenarios, namely, mobile tethers, fixed but random ones, and fixed but ordered ones, and the effects and important limitations of including only binary interactions (excluded volume terms). We find that there is a "mushroom" regime in which the layer thickness is independent of the tethering density, σ, for systems with ordered tethers, but we argue that there is no such plateau for mobile or disordered anchors, nor is there one in the 1D theory. In the other limit of brushes, all approaches predict that the layer thickness scales linearly with N. However, the σ1/3 scaling is a result of keeping only excluded volume interactions: when the full potential is included, the dependence is faster and more complicated than σ1/3. In fact, there does not appear to be any regime in which the layer thickness scales in the combination Nσ1/3. We also compare the results for two different solvents with each other, and with earlier Θ solvent results.

  18. The role of excluded volume and electrostatics from coarse-grain modeling of the interaction of gemini surfactants with like-charged membranes

    NASA Astrophysics Data System (ADS)

    Nunes, Sandra C. C.; Almeida, J. A. S.; Dias, R. S.; Pais, A. A. C. C.

    2013-01-01

    Cationic systems composed of lipids and/or surfactants are of paramount importance in a variety of applications. Within these, gemini have attracted particular attention, mainly due to their improved aggregation properties and to the possibility of tuning offered by the presence of a spacer. In this work, a Monte Carlo simulation study with a coarse-grained model was employed to assess the interaction of cationic gemini surfactants with a like-charged model membrane. Separating the contribution of the excluded volume and that of the electrostatic effects in the organization of gemini-lipid membranes was the first goal of this work and the role of these factors was assessed varying the concentration, the spacer length and the headgroup charge of gemini surfactants. The results provide a new insight on the organization of lipid headgroups in the vicinity of gemini surfactants. It was found that the surfactant-lipid interaction is strongly affected by the surfactant spacer length, being controlled by an overall balance between excluded volume and surfactant-lipid and surfactant-surfactant electrostatic effects. It is also seen that the out-of-plane motion of the spacer has a significant effect upon membrane organization and counterion condensation. Good agreement was found with results previously obtained from atomistic simulation.

  19. An interaction of a NR3C1 polymorphism and antenatal solar activity impacts both hippocampus volume and neuroticism in adulthood

    PubMed Central

    Montag, Christian; Eichner, Markus; Markett, Sebastian; Quesada, Carlos M.; Schoene-Bake, Jan-Christoph; Melchers, Martin; Plieger, Thomas; Weber, Bernd; Reuter, Martin

    2013-01-01

    The investigation of the interaction of genes and environment in the context of mental health and personality yields important new insights for a better understanding of human nature. Both antenatal and postnatal environmental factors have been considered as potential modulators of genetic activity. Antenatally, especially smoking or alcohol drinking habits of the mother dramatically influence the health of the child during pregnancy and even later on in life. In the present study we would like to introduce a more “distant” factor that is not under the control of the becoming mother but that nevertheless plays a potential role for the health of the unborn child later on in adulthood. Here, we retrospectively investigate the influence of solar activity (while the child is still in the uterus of the becoming mother) on brain structure (with a focus on hippocampus and amygdala volume) and personality in adulthood. We observe an interaction of a genetic variant (rs41423247) of the glucocorticoid receptor gene (NR3C1) and solar activity in the first trimester after conception on both hippocampal volume and the personality trait neuroticism in adulthood in N = 254 participants. The NR3C1 gene is the focus of interest, because of its influence on the hypothalamic-pituitary-adrenal (HPA) axis and negative emotionality. Carriers of the CC variant of rs41423247 grown in the womb under the influence of high sun radiation (high solar activity) show both the highest hippocampal volume in the left hemisphere and lowest neuroticism scores. The present findings should encourage researchers in psychology and psychiatry to include also environmental influences such as solar activity besides genetics to better understand the etiogenesis of psychiatric disorders. PMID:23761749

  20. Interaction of Aldosterone and Extracellular Volume in the Pathogenesis of Obesity-Associated Kidney Disease: A Narrative Review

    PubMed Central

    Bomback, Andrew S.; Klemmer, Philip J.

    2009-01-01

    Obesity and obesity-associated kidney injuries have played an important role in the rising prevalence of chronic kidney disease (CKD). The link between obesity and kidney disease begins with obesity's well-known associations with diabetes and hypertension, the two leading etiologies of CKD. However, a growing body of evidence suggests that elevated aldosterone levels and expanded extracellular volume are key components of obesity-induced renal disease via aldosterone's non-epithelial effects on the kidney. Highlighting these blood pressure- and diabetes-independent mechanisms of kidney injury in obesity allows an exploration of whether mineralocorticoid receptor blockade, coupled with weight loss and salt restriction, is an optimal treatment for overweight CKD patients. PMID:19299892

  1. Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 2: Data analysis

    NASA Technical Reports Server (NTRS)

    Wilreker, V. F.; Stiller, P. H.; Scott, G. W.; Kruse, V. J.; Smith, R. F.

    1984-01-01

    Assessing the performance of a MOD-OA horizontal axis wind turbine connected to an isolated diesel utility, a comprehensive data measurement program was conducted on the Block Island Power Company installation on Block Island, Rhode Island. The detailed results of that program focusing on three principal areas of (1) fuel displacement (savings), (2) dynamic interaction between the diesel utility and the wind turbine, (3) effects of three models of wind turbine reactive power control are presented. The approximate two month duration of the data acquisition program conducted in the winter months (February into April 1982) revealed performance during periods of highest wind energy penetration and hence severity of operation. Even under such conditions fuel savings were significant resulting in a fuel reduction of 6.7% while the MOD-OA was generating 10.7% of the total electrical energy. Also, electrical disturbance and interactive effects were of an acceptable level.

  2. A cut-cell finite volume - finite element coupling approach for fluid-structure interaction in compressible flow

    NASA Astrophysics Data System (ADS)

    Pasquariello, Vito; Hammerl, Georg; Örley, Felix; Hickel, Stefan; Danowski, Caroline; Popp, Alexander; Wall, Wolfgang A.; Adams, Nikolaus A.

    2016-02-01

    We present a loosely coupled approach for the solution of fluid-structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet-Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface. The cut-cell procedure inevitably leads to non-matching interfaces, demanding for a special treatment. A Mortar method is chosen in order to obtain a conservative and consistent load transfer. We validate our method by investigating two-dimensional test cases comprising a shock-loaded rigid cylinder and a deformable panel. Moreover, the aeroelastic instability of a thin plate structure is studied with a focus on the prediction of flutter onset. Finally, we propose a three-dimensional fluid-structure interaction test case of a flexible inflated thin shell interacting with a shock wave involving large and complex structural deformations.

  3. Magnetic fusion energy plasma interactive and high heat flux components. Volume I. Technical assessment of the critical issues and problem areas in the plasma materials interaction field

    SciTech Connect

    Conn, R.W.; Gauster, W.B.; Heifetz, D.; Marmar, E.; Wilson, K.L.

    1984-01-01

    A technical assessment of the critical issues and problem areas in the field of plasma materials interactions (PMI) in magnetic fusion devices shows these problems to be central for near-term experiments, for intermediate-range reactor devices including D-T burning physics experiments, and for long-term reactor machines. Critical technical issues are ones central to understanding and successful operation of existing and near-term experiments/reactors or devices of great importance for the long run, i.e., ones which will require an extensive, long-term development effort and thus should receive attention now. Four subgroups were formed to assess the critical PMI issues along four major lines: (1) PMI and plasma confinement physics experiments; (2) plasma-edge modelling and theory; (3) surface physics; and (4) materials technology for in-vessel components and the first wall. The report which follows is divided into four major sections, one for each of these topics.

  4. PNPLA3 gene-by-visceral adipose tissue volume interaction and the pathogenesis of fatty liver disease: The NHLBI Family Heart Study

    PubMed Central

    Graff, M.; North, K.E.; Franceschini, N.; Reiner, A.P.; Feitosa, M.; Carr, J.J.; Gordon-Larsen, P.; Wojczynski, M. K.; Borecki, I.B.

    2012-01-01

    Background Fatty liver disease (FLD) is characterized by increased intrahepatic triglyceride content with or without inflammation and is associated with obesity, and features of the metabolic syndrome. Several recent GWAS have reported an association between SNP rs738409 in the PNPLA3 gene and FLD. Liver attenuation (Hounsfield Units, HU) by computed tomography is a non-invasive measure of liver fat, with lower values of HU indicating higher liver fat content. Clinically, a liver attenuation (LA) value of ≤ 40 HU indicates moderate-to-severe hepatic steatosis. Objective We investigated whether missense rs738409 PNPLA3 interacted with abdominal visceral adipose tissue volume (cm3) to reduce liver attenuation (i.e. increased liver fat) in 1,019 European American men and 1,238 European American women from the Family Heart Study. Methods We used linear regression to test the additive effect of genotype, abdominal visceral adipose tissue (VAT), and their multiplicative interaction on LA adjusted for age, BMI, HDL-cholesterol, insulin resistance, serum triglycerides, abdominal subcutaneous adipose tissue, and alcohol intake. Results In men and women combined, the interaction between each copy of the rs738409 variant allele (MAF 0.23) and 100cm3/150mm slice VAT decreased LA by 2.68±0.35 HU (p < 0.01). The interaction of 100cm3 VAT and the variant allele was associated with a greater decrease in LA in women than men (−4.8±0.6 and −2.2±0.5 HU, respectively). Conclusions The interaction between genotype and VAT volume suggest key differences in the role of PNPLA3 genotype in conjunction with abdominal VAT in liver fat accrual. The stronger association of the PNPLA3 genotype and liver fat in women suggests that women may be more sensitive to liver fat accumulation in the setting of increased visceral fat, compared to men. The presence of the PNPLA3 variant genotype, particularly in the context of high visceral adipose tissue content may play an important role in FLD

  5. Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Wilreker, V. F.; Stiller, P. H.; Scott, G. W.; Kruse, V. J.; Smith, R. F.

    1984-01-01

    Primary results are summarized for a three-part study involving the effects of connecting a MOD-OA wind turbine generator to an isolated diesel power system. The MOD-OA installation considered was the third of four experimental nominal 200 kW wind turbines connected to various utilities under the Federal Wind Energy Program and was characterized by the highest wind energy penetration levels of four sites. The study analyses address: fuel displacement, dynamic interaction, and three modes of reactive power control. These analyses all have as their basis the results of the data acquisition program conducted on Block Island, Rhode Island.

  6. Making intelligent systems team players: Case studies and design issues. Volume 1: Human-computer interaction design

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schreckenghost, Debra L.; Woods, David D.; Potter, Scott S.; Johannesen, Leila; Holloway, Matthew; Forbus, Kenneth D.

    1991-01-01

    Initial results are reported from a multi-year, interdisciplinary effort to provide guidance and assistance for designers of intelligent systems and their user interfaces. The objective is to achieve more effective human-computer interaction (HCI) for systems with real time fault management capabilities. Intelligent fault management systems within the NASA were evaluated for insight into the design of systems with complex HCI. Preliminary results include: (1) a description of real time fault management in aerospace domains; (2) recommendations and examples for improving intelligent systems design and user interface design; (3) identification of issues requiring further research; and (4) recommendations for a development methodology integrating HCI design into intelligent system design.

  7. Experimental study of main rotor tip geometry and tail rotor interactions in hover. Volume 2: Run log and tabulated data

    NASA Technical Reports Server (NTRS)

    Balch, D. T.; Lombardi, J.

    1985-01-01

    A model scale hover test was conducted in the Sikorsky Aircraft Model Rotor hover Facility to identify and quantify the impact of the tail rotor on the demonstrated advantages of advanced geometry tip configurations. The existence of mutual interference between hovering main rotor and a tail rotor was acknowledged in the test. The test was conducted using the Basic Model Test Rig and two scaled main rotor systems, one representing a 1/5.727 scale UH-60A BLACK HAWK and the others a 1/4.71 scale S-76. Eight alternate rotor tip configurations were tested, 3 on the BLACK HAWK rotor and 6 on the S-76 rotor. Four of these tips were then selected for testing in close proximity to an operating tail rotor (operating in both tractor and pusher modes) to determine if the performance advantages that could be obtained from the use of advanced geometry tips in a main rotor only environment would still exist in the more complex flow field involving a tail rotor. This volume contains the test run log and tabulated data.

  8. CALCULATION OF DELTA I = 3/2 KAON WEAK MATRIX ELEMENTS INCLUDING TWO-PION INTERACTION EFFECTS IN FINITE VOLUME.

    SciTech Connect

    YAMAZAKI, T.

    2006-07-23

    We calculate {Delta}I = 3/2 kaon decay matrix elements using domain wall fermions and the DBW2 gauge action at one coarse lattice spacing corresponding to a{sup -1} = 1.3 GeV. We employ the Lellouch and Luescher formula and its extension for non-zero total momentum to extract the infinite volume, center-of-mass frame decay amplitudes. The decay amplitudes obtained from the methods correspond to those from the indirect method with full order chiral perturbation theory. We confirm that the result is consistent with the previous result calculated with H-parity (anti-periodic) boundary condition by investigating the relative momentum dependence. We evaluate the decay amplitude ReA{sub 2} at the physical point by a chiral extrapolation with a polynomial function of m{sub {pi}}{sup 2} and the relative momentum as well as the {Delta}I = 3/2 electroweak penguin contributions to {var_epsilon}{prime}/{var_epsilon}. We found that the result of ReA{sub 2} reasonably agrees with the experiment.

  9. Prediction of Protein Aggregation in High Concentration Protein Solutions Utilizing Protein-Protein Interactions Determined by Low Volume Static Light Scattering.

    PubMed

    Hofmann, Melanie; Winzer, Matthias; Weber, Christian; Gieseler, Henning

    2016-06-01

    The development of highly concentrated protein formulations is more demanding than for conventional concentrations due to an elevated protein aggregation tendency. Predictive protein-protein interaction parameters, such as the second virial coefficient B22 or the interaction parameter kD, have already been used to predict aggregation tendency and optimize protein formulations. However, these parameters can only be determined in diluted solutions, up to 20 mg/mL. And their validity at high concentrations is currently controversially discussed. This work presents a μ-scale screening approach which has been adapted to early industrial project needs. The procedure is based on static light scattering to directly determine protein-protein interactions at concentrations up to 100 mg/mL. Three different therapeutic molecules were formulated, varying in pH, salt content, and addition of excipients (e.g., sugars, amino acids, polysorbates, or other macromolecules). Validity of the predicted aggregation tendency was confirmed by stability data of selected formulations. Based on the results obtained, the new prediction method is a promising screening tool for fast and easy formulation development of highly concentrated protein solutions, consuming only microliter of sample volumes. PMID:27157445

  10. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

    NASA Technical Reports Server (NTRS)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  11. Is the manifestation of the local dynamics in the spin-lattice NMR relaxation in dendrimers sensitive to excluded volume interactions?

    PubMed

    Shavykin, Oleg V; Neelov, Igor M; Darinskii, Anatolii A

    2016-09-21

    The effect of excluded volume (EV) interactions on the manifestation of the local dynamics in the spin-lattice NMR relaxation in dendrimers has been studied by using Brownian dynamics simulations. The study was motivated by the theory developed by Markelov et al., [J. Chem. Phys., 2014, 140, 244904] for a Gaussian dendrimer model without EV interactions. The theory connects the experimentally observed dependence of the spin-lattice relaxation rate 1/T(1)H on the location of NMR active groups with the restricted flexibility (semiflexibility) of dendrimers. Semiflexibility was introduced through the correlations between the orientations of different segments. However, these correlations exist even in flexible dendrimer models with EV interactions. We have simulated coarse-grained flexible and semiflexible dendrimer models with and without EV interactions. Every dendrimer segment consisted of two rigid bonds. Semiflexibility was introduced through a potential which restricts the fluctuations of angles between neighboring bonds but does not change orientational correlations in the EV model as compared to the flexible case. The frequency dependence of the reduced 1/T(1)H(ωH) for segments and bonds belonging to different dendrimer shells was calculated. It was shown that the main effect of EV interactions consists of a much stronger contribution of the overall dendrimer rotation to the dynamics of dendrimer segments as compared to phantom models. After the exclusion of this contribution the manifestation of internal dynamics in spin-lattice NMR relaxation appears to be practically insensitive to EV interactions. For the flexible models, the position ωmax of the peak of the modified 1/T(1)H(ωH) does not depend on the shell number. For semiflexible models, the maximum of 1/T(1)H(ωH) for internal segments or bonds shifts to lower frequencies as compared to outer ones. The dependence of ωmax on the number of dendrimer shells appears to be universal for segments and

  12. Direct Numerical Simulation of Acoustic Waves Interacting with a Shock Wave in a Quasi-1D Convergent-Divergent Nozzle Using an Unstructured Finite Volume Algorithm

    NASA Technical Reports Server (NTRS)

    Bui, Trong T.; Mankbadi, Reda R.

    1995-01-01

    Numerical simulation of a very small amplitude acoustic wave interacting with a shock wave in a quasi-1D convergent-divergent nozzle is performed using an unstructured finite volume algorithm with a piece-wise linear, least square reconstruction, Roe flux difference splitting, and second-order MacCormack time marching. First, the spatial accuracy of the algorithm is evaluated for steady flows with and without the normal shock by running the simulation with a sequence of successively finer meshes. Then the accuracy of the Roe flux difference splitting near the sonic transition point is examined for different reconstruction schemes. Finally, the unsteady numerical solutions with the acoustic perturbation are presented and compared with linear theory results.

  13. Simulating the interaction of the heliosphere with the local interstellar medium: MHD results from a finite volume approach, first bidimensional results

    NASA Technical Reports Server (NTRS)

    Chanteur, G.; Khanfir, R.

    1995-01-01

    We have designed a full compressible MHD code working on unstructured meshes in order to be able to compute accurately sharp structures embedded in large scale simulations. The code is based on a finite volume method making use of a kinetic flux splitting. A bidimensional version of the code has been used to simulate the interaction of a moving interstellar medium, magnetized or unmagnetized with a rotating and magnetized heliopspheric plasma source. Being aware that these computations are not realistic due to the restriction to two dimensions, we present it to demonstrate the ability of this new code to handle this problem. An axisymetric version, now under development, will be operational in a few months. Ultimately we plan to run a full 3d version.

  14. STEALTH: a Lagrange explicit finite-difference code for solid, structural, and thermohydraulic analysis. Volume 8B. STEALTH/WHAMSE: a 3-D fluid-structure interaction code

    SciTech Connect

    Not Available

    1984-10-01

    STEALTH is a family of computer codes that can be used to calculate a variety of physical processes in which the dynamic behavior of a continuum is involved. The version of STEALTH described in this volume is designed for calculations of fluid-structure interaction. This version of the program consists of a hydrodynamic version of STEALTH which has been coupled to a finite-element code, WHAMSE. STEALTH computes the transient response of the fluid continuum, while WHAMSE computes the transient response of shell and beam structures under external fluid loadings. The coupling between STEALTH and WHAMSE is performed during each cycle or step of a calculation. Separate calculations of fluid response and structure response are avoided, thereby giving a more accurate model of the dynamic coupling between fluid and structure. This volume provides the theoretical background, the finite-difference equations, the finite-element equations, a discussion of several sample problems, a listing of the input decks for the sample problems, a programmer's manual and a description of the input records for the STEALTH/WHAMSE computer program.

  15. Raman Line Imaging of Poly(ε-caprolactone)/Carbon Dioxide Solutions at High Pressures: A Combined Experimental and Computational Study for Interpreting Intermolecular Interactions and Free-Volume Effects.

    PubMed

    Pastore Carbone, Maria Giovanna; Musto, Pellegrino; Pannico, Marianna; Braeuer, Andreas; Scherillo, Giuseppe; Mensitieri, Giuseppe; Di Maio, Ernesto

    2016-09-01

    In the present study, a Raman line-imaging setup was employed to monitor in situ the CO2 sorption at elevated pressures (from 0.62 to 7.10 MPa) in molten PCL. The method allowed the quantitative measurement of gas concentration in both the time-resolved and the space-resolved modes. The combined experimental and theoretical approach allowed a molecular level characterization of the system. The dissolved CO2 was found to occupy a volume essentially coincident with its van der Waals volume and the estimated partial molar volume of the probe did not change with pressure. Lewis acid-Lewis base interactions with the PCL carbonyls was confirmed to be the main interaction mechanism. The geometry of the supramolecular complex and the preferential interaction site were controlled more by steric than electronic effects. On the basis of the indications emerging from Raman spectroscopy, an equation of state thermodynamic model for the PCL-CO2 system, based upon a compressible lattice fluid theory endowed with specific interactions, has been tailored to account for the interaction types detected spectroscopically. The predictions of the thermodynamic model in terms of molar volume of solution have been compared with available volumetric measurements while predictions for CO2 partial molar volume have been compared with the values estimated on the basis of Raman spectroscopy. PMID:27454947

  16. Proceedings of RIKEN BNL Research Center Workshop: The Approach to Equilibrium in Strongly Interacting Matter. Volume 118

    SciTech Connect

    Liao, J.; Venugopalan, R.; Berges, J.; Blaizot, J. -P.; Gelis, F.

    2014-04-09

    The RIKEN BNL Research Center (RBRC) was established in April 1997 at Brookhaven National Laboratory*. It is funded by the ''Rikagaku Kenkyusho'' (RIKEN, The Institute of Physical and Chemical Research) of Japan and the U. S. Department of Energy’s Office of Science. The RBRC is dedicated to the study of strong interactions, including spin physics, lattice QCD, and RHIC physics through the nurturing of a new generation of young physicists. The RBRC has theory, lattice gauge computing and experimental components. It is presently exploring the possibility of an astrophysics component being added to the program. The purpose of this Workshop is to critically review the recent progress on the theory and phenomenology of early time dynamics in relativistic heavy ion collisions from RHIC to LHC energies, to examine the various approaches on thermalization and existing issues, and to formulate new research efforts for the future. Topics slated to be covered include Experimental evidence for equilibration/isotropization, comparison of various approaches, dependence on the initial conditions and couplings, and turbulent cascades and Bose-Einstein condensation.

  17. Application of the Molecular Interaction Volume Model (MIVM) to Calcium-Based Liquid Alloys of Systems Forming High-Melting Intermetallics

    SciTech Connect

    Poizeau, S; Sadoway, DR

    2013-06-05

    The thermodynamic properties of multiple liquid alloys with strong negative deviation from ideality were successfully modeled by the molecular interaction volume model (MIVM). The modeled partial Gibbs free energy of calcium in Ca-Ag, Ca-In, Ca-Pb, Ca-Sn, Ca-Tl, and Ca-Zn at 800 degrees C was within 1.5 kJ/mol of the existing experimental data. The partial Gibbs free energy of calcium in Ca-Bi liquid alloys at 600 degrees C was predicted within 1.6 kJ/mol (or 1%) by the MIVM from experimental data at 800 degrees C. For the first time, the MIVM was applied to a ternary system far from ideality, Ca-Sb-Pb. The partial Gibbs free energy of Ca in six Ca-Pb-Sb alloys was determined by emf measurements in a cell configured as Ca(s)vertical bar CaF2(s)vertical bar Ca-Sb-Pb, over the temperature range of 500-830 degrees C. These values were 2% (or 5 kJ/mol) more negative than those predicted by the MIVM using experimental data for the Ca-Pb, Ca-Sb, and Pb-Sb binary alloys. This difference was attributed to the inability of the MIVM to account for interactions between the first nearest neighbors of Ca, Pb and Sb in the ternary Ca-Sb-Pb alloy.

  18. Coupled 2-dimensional cascade theory for noise and unsteady aerodynamics of blade row interaction in turbofans. Volume 1: Theory development and parametric studies

    NASA Technical Reports Server (NTRS)

    Hanson, Donald B.

    1994-01-01

    Typical analytical models for interaction between rotor and stator in a turbofan analyze the effect of wakes from the rotor impinging on the stator, producing unsteady loading, and thereby generating noise. Reflection/transmission characteristics of the rotor are sometimes added in a separate calculation. In those models, there is a one-to-one relationship between wake harmonics and noise harmonics; that is, the BPF (blade passing frequency) wake harmonic causes only the BPF noise harmonic, etc. This report presents a more complete model in which flow tangency boundary conditions are satisfied on two cascades in relative motion for several harmonics simultaneously. By an extension of S.N. Smith's code for two dimensional flat plate cascades, the noise generation/frequency scattering/blade row reflection problem is solved in a single matrix inversion. It is found that the BPF harmonic excitation of the stator scatters considerable energy in the higher BPF harmonics due to relative motion between the blade rows. Furthermore, when swirl between the rotor and stator is modeled, a 'mode trapping' effect occurs which explains observations on fans operating at rotational speeds below BFP cuton: the BPF mode amplifies between blade rows by multiple reflections but cannot escape to the inlet and exit ducts. However, energy scattered into higher harmonics does propagate and dominates the spectrum at two and three times BPF. This report presents the complete derivation of the theory, comparison with a previous (more limited) coupled rotor/stator interaction theory due to Kaji and Okazaki, exploration of the mode trapping phenomenon, and parametric studies showing the effects of vane/blade ratio and rotor/stator interaction. For generality, the analysis applies to stages where the rotor is either upstream or downstream of the stator and to counter rotation stages. The theory has been coded in a FORTRAN program called CUP2D, documented in Volume 2 of this report. It is

  19. In vivo multispectral photoacoustic and photothermal flow cytometry with multicolor dyes: a potential for real-time assessment of circulation, dye-cell interaction, and blood volume

    PubMed Central

    Proskurnin, Mikhail A.; Zhidkova, Tatyana V.; Volkov, Dmitry S.; Sarimollaoglu, Mustafa; Galanzha, Ekaterina I.; Mock, Donald; Zharov, Vladimir P.

    2011-01-01

    Recently, photoacoustic (PA) flow cytometry (PAFC) has been developed for in vivo detection of circulating tumor cells and bacteria targeted by nanoparticles. Here, we propose multispectral PAFC with multiple dyes having distinctive absorption spectra as multicolor PA contrast agents. As a first step of our proof-of-concept, we characterized high-speed PAFC capability to monitor the clearance of three dyes (ICG, MB, and TB) in an animal model in vivo and in real time. We observed strong dynamic PA signal fluctuations, which can be associated with interactions of dyes with circulating blood cells and plasma proteins. PAFC demonstrated enumeration of circulating red and white blood cells labeled with ICG and MB, respectively, and detection of rare dead cells uptaking TB directly in bloodstream. The possibility for accurate measurements of various dye concentrations including CV and BG were verified in vitro using complementary to PAFC photothermal (PT) technique and spectrophotometry under batch and flow conditions. We further analyze the potential of integrated PAFC/PT spectroscopy with multiple dyes for rapid and accurate measurements of circulating blood volume without a priori information on hemoglobin content, which is impossible with existing optical techniques. This is important in many medical conditions including surgery and trauma with extensive blood loss, rapid fluid administration, transfusion of red blood cells. The potential for developing a robust clinical PAFC prototype that is, safe for human, and its applications for studying the liver function are further highlighted. PMID:21905207

  20. Late Pleistocene ice-shelf, valley-glacier and ice-sheet interactions on Alexander Island, Antarctic Peninsula: implications for climatic and ice-volume changes

    NASA Astrophysics Data System (ADS)

    Davies, Bethan; Hambrey, Michael; Glasser, Neil; Smellie, John; Carrivick, Jonathan; Bentley, Michael

    2014-05-01

    Recent rapid warming across the Antarctic Peninsula has resulted in ice-sheet thinning, dramatic ice-shelf collapse, acceleration of ice-flow velocities and widespread glacier recession. Reconstructing past rates, volumes and magnitudes of cryospheric change, particularly with respect to the former configuration of ice sheets and ice shelves, and their response to changing oceanic and climatic regimes, is vital in providing a context for this change, in order to improve predictions of future ice-sheet behaviour, and to provide glacio-isostatic adjustment corrections for gravimetric measurements of contemporary ice loss. This research aimed to investigate valley glacier and ice-shelf interactions during the Last Glacial Maximum (LGM) and Holocene Epoch across George VI Sound and Alexander Island, western Antarctic Peninsula, an area with a well-preserved but poorly dated record. We identify four principal stratigraphic units: (1) a high-elevation drift with Alexander Island erratics only (interpreted as recording older advances of ice from the interior of the island), (2) a lower-elevation drift with exotic Palmer Land erratics (interpreted as ice-shelf moraine, representing incursions of George VI Ice Shelf onto Ablation Point Massif), (3) multiple overlapping sequences of valley glacier moraine and ice-shelf moraine, presumed to be Holocene in age, and (4) more recent processes and units, including frozen epishelf lakes, slope processes and alluvial fans. On-going cosmogenic nuclide dating on these sediments (in progress; 25 10Be exposure ages) has the potential to unlock the complex history and interactions of ice streams, valley glaciers and ice shelves in this area. This work will also provide the first long-term record of sea-level indicators, allowing the first estimates of glacial unloading, rates of uplift and ice-sheet thinning to be calculated. The Holocene record of the ice shelf, preserved in the younger ice-shelf moraines and in the overlapping

  1. Projection models for health-effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume III. SPAHR interactive package guide

    SciTech Connect

    Collins, J.J.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projectons. The model extends several health risk projection models by making realistic assumptions about the population at risk, adn thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of response, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, number of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projections are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. This manual outlines the use of the interactive capabilities of SPAHR. SPAHR is an integrated system of computer programs designed for simulating numerous health risk scenarios using the techniques of demographic modeling. This system of computer programs has been designed to be very flexible so as to allow the user to simulate a large variety of scenarios. It provides the user with an integrated package for projecting the impacts on human health of exposure to various hazards, particularly those resulting from the effluents related to energy production.

  2. Direct volume editing.

    PubMed

    Bürger, Kai; Krüger, Jens; Westermann, Rüdiger

    2008-01-01

    In this work we present basic methodology for interactive volume editing on GPUs, and we demonstrate the use of these methods to achieve a number of different effects. We present fast techniques to modify the appearance and structure of volumetric scalar fields given on Cartesian grids. Similar to 2D circular brushes as used in surface painting we present 3D spherical brushes for intuitive coloring of particular structures in such fields. This paint metaphor is extended to allow the user to change the data itself, and the use of this functionality for interactive structure isolation, hole filling, and artefact removal is demonstrated. Building on previous work in the field we introduce high-resolution selection volumes, which can be seen as a resolution-based focus+context metaphor. By utilizing such volumes we present a novel approach to interactive volume editing at sub-voxel accuracy. Finally, we introduce a fast technique to paste textures onto iso-surfaces in a 3D scalar field. Since the texture resolution is independent of the volume resolution, this technique allows structure-aligned textures containing appearance properties or textual information to be used for volume augmentation and annotation. PMID:18988988

  3. Use of hydrocyclone and flotation column for reducing the volume of contaminated dredged material.

    PubMed

    Park, K H; Lee, J H; Bae, B H; Kim, Y H; Choung, Y K

    2006-01-01

    As sediment contamination problems have recently been raised in Korea, the need for technologies to clean contaminants in sediments has increased. Although the recalcitrant organic matters and heavy metals in the contaminated sediments are of primary concern, large amounts of sediment makes the removal of the contaminants in them more difficult. In this study, the performance of hydrocyclone and flotation column was tested to reduce the volume of contaminated dredged materials (CDMs) prior to treating recalcitrant matters, such as various organic chemicals and heavy metals, in an integrated treatment system. When hydrocyclone was operated with 10% (w/v) solids concentration of the feed slurry, the total solids of upflow products were 4 to 7% (w/v) when the inlet pressure was changed from 1.0 to 2.0 kg/cm2. The volume reduction ratio of CDMs by hydrocyclone was approximately 90% (v/v). When the upflow products in hydrocyclone was then spiked with automobile transmission oil and fed to the flotation colum to see the performance of the column flotation on the volume reduction and the TPH removal, 44% of the TPHs in feed were removed at the tails and the volume reduction ratio of CDMs by column flotation was 18% at 200 L/min of wash water. The flotation column could be proposed as a potential preliminary treatment process of CDMs prior to subsequent biological treatments. PMID:16752776

  4. MODIFIED N.R.C. VERSION OF THE U.S.G.S. SOLUTE TRANSPORT MODEL. VOLUME 2. INTERACTIVE PREPROCESSOR PROGRAM

    EPA Science Inventory

    The methods described in the report can be used with the modified N.R.C. version of the U.S.G.S. Solute Transport Model to predict the concentration of chemical parameters in a contaminant plume. The two volume report contains program documentation and user's manual. The program ...

  5. LOCA hydroloads calculations with multidimensional nonlinear fluid/structure interaction. Volume 2: STEALTH 2D/WHAMSE 2D single-phse fluid and elastic structure studies. Final report. [PWR

    SciTech Connect

    Chang, F.H.; Santee, G.E. Jr.; Mortensen, G.A.; Brockett, G.F.; Gross, M.B.; Silling, S.A.; Belytschko, T.

    1981-03-01

    This report, the second in a series of reports for RP-1065, describes the second step in the stepwise approach for developing the three-dimensional, nonlinear, fluid/structure interaction methodology to assess the hydroloads on a large PWR during the subcooled portions of a hypothetical LOCA. The second step in the methodology considers enhancements and special modifications to the 2D STEALTH-HYDRO computer program and the 2D WHAMSE computer program. The 2D STEALTH-HYDRO enhancements consist of a fluid-fluid coupling control-volume model and an orifice control-volume model. The enhancements to 2D WHAMSE include elimination of the implicit integration routines, material models, and structural elements not required for the hydroloads application. In addition the logic for coupling the 2D STEALTH-HYDRO computer program to the 2D WHAMSE computer program is discussed.

  6. LOCA hydroloads calculations with multidimensional nonlinear fluid/structure interaction. Volume 1: STEALTH 1D single-phase fluid studies. Final report. [PWR

    SciTech Connect

    Santee, G.E. Jr.; Mortensen, G.A.; Caraher, D.L.

    1980-04-01

    This report, which is the first in a series of reports for RP-1065, describes the first step in the stepwise approach for developing the methodology to assess the hydroloads on a large PWR during the subcooled portions of a hypothetical LOCA. The first step in the methodology considers enhancements and special modifications to the 1D STEALTH computer code in order that acoustic phenomena in piping and vessel networks may be simulated. The resulting code is termed 1D STEALTH-HYDRO. The 1D STEALTH-HYDRO enhancements consist of three control volume models to simulate area changes, orifices, and tees in piping networks. The theory of the control volume models is described.

  7. Monitoring and Modelling of Soil-Plant Interactions: the Joint Use of ERT, Sap Flow and Eddy Covariance to Define the Volume of Orange Tree Active Root Zones.

    NASA Astrophysics Data System (ADS)

    Cassiani, G.; Boaga, J.; Vanella, D.; Perri, M. T.; Consoli, S.

    2014-12-01

    Mass and energy exchanges between soil, plants and atmosphere are key factors controlling a number of environmental processes involving hydrology, biota and climate. The understanding of these exchanges also play a critical role for practical purposes such as precision agriculture. In this contribution we present a methodology based on coupling innovative data collection and models. In particular we propose the use of hydro-geophysical monitoring via 4D Electrical Resistivity Tomography (ERT) in conjunction with measurements of plant transpiration via sap flow and evapotranspiration from Eddy Correlation (EC). This abundance of data are to be fed in spatially distributed soil models in order to comprehend the distribution of active roots. We conducted experiments in an orange orchard in Eastern Sicily (Italy). We installed a 3D electrical tomography apparatus consisting of 4 instrumented micro boreholes placed at the corners of a square (about 1.3 m in side) surrounding an orange tree. During the monitoring, we collected repeated ERT and TDR soil moisture measurements, soil water sampling, sap flow measurements from the orange tree and EC data. Irrigation, precipitation, sap flow and ET data are available for a long period of time allowing knowledge of the long term forcing conditions on the system. This wealth of information was used to calibrate a 1D Richards' equation model representing the dynamics of the volume monitored via 3D ERT. Information on the soil hydraulic properties was collected from laboratory experiments as well as by time-lapse ERT monitoring of irrigation a few months after the main experiment, when the orange tree had been cut. The results of the calibrated modeling exercise allow the quantification of the soil volume interested by root water uptake. This volume is much smaller (an area less than 2 square meters, 40 cm thick) than generally believed and assumed in the design of classical drip irrigation schemes.

  8. DUMAND Summer Workshop, University of California, La Jolla, Calif., July 24-September 2, 1978, Proceedings. Volume 2 - UHE interactions, neutrino astronomy

    NASA Technical Reports Server (NTRS)

    Roberts, A.

    1979-01-01

    The volume covers categories on inelastic neutrino scattering and the W-boson, and other ultra-high-energy processes, on pulsars, quasars and galactic nuclei, as well as other point sources and constants from gamma ray astronomy. Individual subjects include weak intermediate vector bosons and DUMAND, the Monte Carlo simulation of inelastic neutrino scattering in DUMAND, and Higgs boson production by very high-energy neutrinos. The observability of the neutrino flux from the inner region of the galactic disk, the diffuse fluxes of high-energy neutrinos, as well as the significance of gamma ray observations for neutrino astronomy are also among the topics covered.

  9. Development of an Interactive Shoreline Management Tool for the Lower Wood River Valley, Oregon - Phase I: Stage-Volume and Stage-Area Relations

    USGS Publications Warehouse

    Haluska, Tana L.; Snyder, Daniel T.

    2007-01-01

    This report presents the parcel and inundation area geographic information system (GIS) layers for various surface-water stages. It also presents data tables containing the water stage, inundation area, and water volume relations developed from analysis of detailed land surface elevation derived from Light Detection and Ranging (LiDAR) data recently collected for the Wood River Valley at the northern margin of Agency Lake in Klamath County, Oregon. Former shoreline wetlands that have been cut off from Upper Klamath and Agency Lakes by dikes might in the future be reconnected to Upper Klamath and Agency Lakes by breaching the dikes. Issues of interest associated with restoring wetlands in this way include the area that will be inundated, the volume of water that may be stored, the change in wetland habitat, and the variation in these characteristics as surface-water stage is changed. Products from this analysis can assist water managers in assessing the effect of breaching dikes and changing surface-water stage. The study area is in the approximate former northern margins of Upper Klamath and Agency Lakes in the Wood River Valley.

  10. Image space adaptive volume rendering

    NASA Astrophysics Data System (ADS)

    Corcoran, Andrew; Dingliana, John

    2012-01-01

    We present a technique for interactive direct volume rendering which provides adaptive sampling at a reduced memory requirement compared to traditional methods. Our technique exploits frame to frame coherence to quickly generate a two-dimensional importance map of the volume which guides sampling rate optimisation and allows us to provide interactive frame rates for user navigation and transfer function changes. In addition our ray casting shader detects any inconsistencies in our two-dimensional map and corrects them on the fly to ensure correct classification of important areas of the volume.

  11. High-resolution x-ray imaging of Kα volume radiation induced by high-intensity laser pulse interaction with a copper target

    NASA Astrophysics Data System (ADS)

    Galtier, E.; Moinard, A.; Khattak, F. Y.; Renner, O.; Robert, T.; Santos, J. J.; Beaucourt, C.; Angelo, P.; Tikhonchuk, V.; Rosmej, F. B.

    2012-10-01

    In a proof of principle experiment using the LULI 100-TW laser facility ELFIE, we have demonstrated high spectral and spatial resolution of Kα volume radiation induced by energetic electrons generated by irradiating solid Cu targets with visible (0.53 µm) 350 fs laser pulses. Employing an x-ray spectrometer equipped with the spherically bent crystal of quartz (502) and with an image plate, single shot Cu-Kα radiation was recorded in first-order reflection allowing for a geometrical mapping of the emission induced by hot electrons with a spatial resolution down to 30 µm. The simultaneously achieved high spectral resolution permitted the identification of asymmetries in the Kα1-group emission profile. Data from the shot in which a part of the laser beam was incident at grazing angle to the target surface show a signature of enhanced lateral transport of energetic electrons.

  12. Comparison between finite volume and lattice-Boltzmann method simulations of gas-fluidised beds: bed expansion and particle-fluid interaction force

    NASA Astrophysics Data System (ADS)

    Third, J. R.; Chen, Y.; Müller, C. R.

    2016-07-01

    Lattice-Boltzmann method (LBM) simulations of a gas-fluidised bed have been performed. In contrast to the current state-of-the-art coupled computational fluid dynamics-discrete element method (CFD-DEM) simulations, the LBM does not require a closure relationship for the particle-fluid interaction force. Instead, the particle-fluid interaction can be calculated directly from the detailed flow profile around the particles. Here a comparison is performed between CFD-DEM and LBM simulations of a small fluidised bed. Simulations are performed for two different values of the superficial gas velocity and it is found that the LBM predicts a larger bed expansion for both flowrates. Furthermore the particle-fluid interaction force obtained for LBM simulations is compared to the force which would be predicted by a CFD-DEM model under the same conditions. On average the force predicted by the CFD-DEM closure relationship is found to be significantly smaller than the force obtained from the LBM.

  13. Engineering characterization of ground motion. Task II. Effects of ground motion characteristics on structural response considering localized structural nonlinearities and soil-structure interaction effects. Volume 2

    SciTech Connect

    Kennedy, R.P.; Kincaid, R.H.; Short, S.A.

    1985-03-01

    This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. Task I of the study, which is presented in NUREG/CR-3805, Vol. 1, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in four parts: (1) effects of ground motion characteristics on structural response of a typical PWR reactor building with localized nonlinearities and soil-structure interaction effects; (2) empirical data on spatial variations of earthquake ground motion; (3) soil-structure interaction effects on structural response; and (4) summary of conclusions and recommendations based on Tasks I and II studies. This report presents the results of the first part of Task II. The results of the other parts will be presented in NUREG/CR-3805, Vols. 3 to 5.

  14. Do aquatic insects avoid cadmium-contaminated sediments?

    SciTech Connect

    Hare, L.; Shooner, F.

    1995-06-01

    The long-term colonization of profundal lake sediments having a range of spiked cadmium (Cd) concentrations (0.007 to 2.7 {mu}mol/g dry wt.) was measured in the field. Population densities of two of the most abundant colonizing insects (the chironomids Procladius [Holotanypus] sp., and Sergentia coracina) were unrelated to the Cd gradient, even though both taxa accumulated Cd in direct relation to its concentration in sediment Cd gradient Cd gradient. Cadmium concentrations in Chironomus (salinarius gp.) sp. larvae also responded positively to the sediment Cd gradient and ranged from 0.2 to 50 {mu}g/g. In contrast with the two other taxa, the abundance of Chironomus (salinarius gp.) sp. was the result of a behavioral or a toxic response, larvae of the three chironomid taxa were given a choice between field-control and Cd-spiked sediments in the laboratory. None of the taxa avoided the Cd-spiked sediments, suggesting that the lower abundance of Chironomus (salinarius gp.) sp. at high Cd concentrations in the field was due to Cd toxicity and not to avoidance of the Cd-rich sediments.

  15. GEOCHEMICAL FACTORS GOVERNING METHYL MERCURY PRODUCTION IN MERCURY CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Bench scale experiments were conducted to improve our understanding of aquatic mercury transformation processes (biotic and abiotic), specifically those factors which govern the production of methyl mercury (MeHg) in sedimentary environments. The greatest cause for concern regar...

  16. COPING WITH CONTAMINATED SEDIMENTS AND SOILS IN THE URBAN ENVIRONMENT.

    SciTech Connect

    JONES,K.W.; VAN DER LELIE,D.; MCGUIGAN,M.; ET AL.

    2004-05-25

    Soils and sediments contaminated with toxic organic and inorganic compounds harmful to the environment and to human health are common in the urban environment. We report here on aspects of a program being carried out in the New York/New Jersey Port region to develop methods for processing dredged material from the Port to make products that are safe for introduction to commercial markets. We discuss some of the results of the program in Computational Environmental Science, Laboratory Environmental Science, and Applied Environmental Science and indicate some possible directions for future work. Overall, the program elements integrate the scientific and engineering aspects with regulatory, commercial, urban planning, local governments, and community group interests. Well-developed connections between these components are critical to the ultimate success of efforts to cope with the problems caused by contaminated urban soils and sediments.

  17. Mercury Contaminated Sediment Sites: A Review Of Remedial Solutions

    EPA Science Inventory

    Mercury (Hg) can accumulate in sediment from point and non-point sources, depending on a number of physical, chemical, biological, geological and anthropogenic environmental processes. It is believed that the associated Hg contamination in aquatic systems can be decreased by imp...

  18. Mercury Contaminated Sediment Sites- An Evaluation of Remedial Options

    EPA Science Inventory

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to m...

  19. Test system for exposing fish to resuspended, contaminated sediment

    USGS Publications Warehouse

    Cope, W.G.; Wiener, J.G.; Steingraeber, M.T.

    1996-01-01

    We describe a new test system for exposing fish to resuspended sediments and associated contaminants. Test sediments were resuspended by revolving test chambers on rotating shafts driven by an electric motor. The timing, speed, and duration of test-chamber revolution were controlled by a rheostat and electronic timer. Each chamber held 45 litres of water and accommodated about 49 g of test fish. The system described had three water baths, each holding six test chambers. We illustrate the performance of this system with results from a 28-day test in which juvenile bluegills Lepomis macrochirus were exposed to resuspended, riverine sediments differing in texture and cadmium content. The test had one sediment-free control and five sediment treatments, with three replicates (chambers) per treatment and 25 fish per replicate. Two-thirds (30 litres) of the test water and sediment in each chamber was renewed weekly. The mean concentration of total suspended solids (TSS) did not vary among treatments; the grand-mean TSS in the five sediment treatments was 975 mg litre-1, similar to the target TSS of 1000 mg litre-1. At the end of the test, an average of 50% of the introduced cadmium was associated with the suspended sediment compartment, whereas the filtered (0.45 μm) water contained 0.4% and bluegills 1.8% of the cadmium.

  20. STUDY OF ABYSSAL SEAFLOOR ISOLATION OF CONTAMINATED SEDIMENTS CONCLUDED

    EPA Science Inventory

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL...

  1. PILOT LAND TREATMENT OF PAH-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Hazardous dredged sediments are typically placed in confined disposal facilities (CDFs) which are designed to dewater and contain but not treat sediments. Since navigational dredging in the U.S. is quickly filling many CDFs, these facilities have little available capacity for ne...

  2. Cluster analysis of contaminated sediment data: nodal analysis.

    PubMed

    Hartwell, S Ian; Claflin, Larry W

    2005-07-01

    The objective of the present study was to explore the use of multivariate statistical methods as a means to discern relationships between contaminants and biological and/or toxicological effects in a representative data set from the National Status and Trends (NS&T) Program. Data from the National Oceanic and Atmospheric Administration, NS&T Program's Bioeffects Survey of Delaware Bay, USA, were examined using various univariate and multivariate statistical techniques, including cluster analysis. Each approach identified consistent patterns and relationships between the three types of triad data. The analyses also identified factors that bias the interpretation of the data, primarily the presence of rare and unique species and the dependence of species distributions on physical parameters. Sites and species were clustered with the unweighted pair-group method using arithmetic averages clustering with the Jaccard coefficient that clustered species and sites into mutually consistent groupings. Pearson product moment correlation coefficients, normalized for salinity, also were clustered. The most informative analysis, termed nodal analysis, was the intersection of species cluster analysis with site cluster analysis. This technique produced a visual representation of species association patterns among site clusters. Site characteristics, such as salinity and grain size, not contaminant concentrations, appeared to be the primary factors determining species distributions. This suggests the sediment-quality triad needs to use physical parameters as a distinct leg from chemical concentrations to improve sediment-quality assessments in large bodies of water. Because the Delaware Bay system has confounded gradients of contaminants and physical parameters, analyses were repeated with data from northern Chesapeake Bay, USA, with similar results. PMID:16050601

  3. Study of abyssal seafloor isolation of contaminated sediments concluded

    SciTech Connect

    Valent, P.

    1998-12-31

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL) conducted and managed the assessment, which was funded during its first year by the Strategic Environmental Research and Development Program and in the following two years by the Defense Advanced Research Projects Agency. NRL carried out the projects in collaboration with participants from academic institutions and industrial organizations. The seafloor isolation concept is an attractive management option for contaminated dredged material because, if abyssal isolation is feasible and environmentally sound, air, land, or water supplies would not be contaminated. The participants concluded that it is technically and environmentally feasible. In ports where shipping costs are high, abyssal seafloor isolation is a cost-competitive strategy. They also outlined the architecture of a system to monitor conditions at the site and to detect and measure possible leaks of contaminated material.

  4. DEVELOPMENT OF REGIONAL CONTAMINATED SEDIMENT INVENTORY FOR NEW ENGLAND

    EPA Science Inventory

    Contaminated aquatic sediments are integrators of historical and recently deposited contaminants, are useful indicators of environmental degradation, and have direct and indirect effects to biota and human health. In 1997, EPA released the first ever comprehensive Report to Cong...

  5. TOXICITY IDENTIFICATION EVALUATION (TIE) RESULTS FOR METAL CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Identification of contaminants in sediment is necessary for sound management decisions on sediment disposal, remediation, determination of ecological risk, and source identification. We have been developing sediment toxicity identification evaluation (TIE) techniques that allow ...

  6. Quantification of thorium and uranium sorption to contaminated sediments

    SciTech Connect

    Kaplan, D.I.

    2000-08-01

    Desorption tests using a sequential extraction method were used to characterize and quantify thorium and uranium sorption to contaminated wetland sediments collected from the Savannah River Site located in South Carolina. In situ distribution coefficients, or Kd values (Kd equal to Csolid/Cliquid), were determined. A problem associated with determining desorption Kd values is that it is difficult to identify Csolid, because by definition it must comprise only the fraction that is reversibly (and linearly) sorbed. A series of selective and sequential extractions was used to determine desorption Kd values. Thorium Kd values ranged from 115 to 2255 mL/g. Uranium Kd values ranged from 170 to 6493 mL/g. Compared to sorption Kd values, these desorption Kd values were appreciably greater because they captured the ``aging'' process of the radionuclides with the sediment, making the radionuclide more refractory. Compared to nonsite-specific data, these in situ Kd values improved accuracy, were more defensible, reduced uncertainty, and removed unnecessary conservatism for subsequent transport and risk calculations. Additional tests were conducted to provide geochemical information relevant for selecting appropriate remediation technologies for the contaminated site. Thorium and U were associated with labile fractions and were not concentrated with the smaller sediment particles. These findings suggest that phytoremediation or heap leaching, and not soil washing, are viable remediation approaches for this site.

  7. Quantum volume

    NASA Astrophysics Data System (ADS)

    Ryabov, V. A.

    2015-08-01

    Quantum systems in a mechanical embedding, the breathing mode of a small particles, optomechanical system, etc. are far not the full list of examples in which the volume exhibits quantum behavior. Traditional consideration suggests strain in small systems as a result of a collective movement of particles, rather than the dynamics of the volume as an independent variable. The aim of this work is to show that some problem here might be essentially simplified by introducing periodic boundary conditions. At this case, the volume is considered as the independent dynamical variable driven by the internal pressure. For this purpose, the concept of quantum volume based on Schrödinger’s equation in 𝕋3 manifold is proposed. It is used to explore several 1D model systems: An ensemble of free particles under external pressure, quantum manometer and a quantum breathing mode. In particular, the influence of the pressure of free particle on quantum oscillator is determined. It is shown also that correction to the spectrum of the breathing mode due to internal degrees of freedom is determined by the off-diagonal matrix elements of the quantum stress. The new treatment not using the “force” theorem is proposed for the quantum stress tensor. In the general case of flexible quantum 3D dynamics, quantum deformations of different type might be introduced similarly to monopole mode.

  8. Kauai endangered seabird study. Volume 1: Interactions of Dark-Rumped Petrels and Newell`s Shearwaters with utility structures on Kauai, Hawaii. Final report

    SciTech Connect

    Cooper, B.A.; Day, R.H.

    1995-12-01

    Declining populations of two endangered species of seabirds on Kauai, Hawaii--the Dark-Rumped Petrel and Newell`s Shearwater--have been the emphasis of a three-year research program to determine the causes of bird mortality and fallout and to recommend preventive measures. This study refined scientific understanding of the timing of bird movements, enabling future biologists to sample rates of avian traffic more efficiently and perhaps better identify the times when it would be most beneficial to reduce outdoor lighting, which has been linked to fallout. The study also identified three specific areas where collisions would be most beneficial. A sampling site was established in the highlands along a transmission line that runs from the south shore to the north shore through the interior and in proximity to several shearwater colonies. This site has provided a much clearer picture of Procellariiform behavior and collision mortality rates in the coastal areas. Volume 2 of this report describes the ecology of the Dark-Rumped Petrel and Newell`s Shearwater on the island of Kauai.

  9. Proceedings: EPRI/NRC/TPC workshop on seismic soil-structure interaction analysis techniques using data from Lotung, Taiwan: Volume 2

    SciTech Connect

    Not Available

    1989-03-01

    A two-and-a-half-day workshop on evaluation of seismic soil-structure interaction (SSI) analysis techniques was held in Palo Alto on December 9--11, 1987. The workshop was co-sponsored by the Electric Power Research Institute (EPRI), the United States Nuclear Regulatory Commission (NRC), and the Taiwan Power Company (TPC) as part of the joint research program on SSI method evaluation. The primary objective of the workshop was to provide a forum for the presentation and discussion of the blind prediction analyses and results comparisons against the forced vibration test measurements and recorded earthquake response data from the EPRI/TPC large-scale seismic experiment in Lotung, Taiwan, Republic of China. These proceedings contain the text of the presentation materials as well as the summaries of panel session discussions.

  10. EPRI/NRC/TPC workshop on seismic soil-structure interaction analysis techniques using data from Lotung, Taiwan: Proceedings: Volume 1

    SciTech Connect

    Not Available

    1989-03-01

    A two-and-a-half-day workshop on evaluation of seismic soil-structure interaction (SSI) analysis techniques was held in Palo Alto on December 9--11, 1987. The workshop was co-sponsored by the Electric Power Research Institute (EPRI), the United States Nuclear Regulatory Commission (NRC), and the Taiwan Power Company (TPC) as part of the joint research program on SSI method evaluation. The primary objective of the workshop was to provide a forum for the presentation and discussion of the blind prediction analyses and results comparisons against the forced vibration test measurements and recorded earthquake response data from the EPRI/TPC large-scale seismic experiment in Lotung, Taiwan, Republic of China. These proceedings contain the test of the presentation materials as well as the summaries of panel session discussions.

  11. Chemical interactions in isolated coal-fired power plant plumes: conversion of sulfur dioxide to sulfate aerosols. Volume II. Data supplement

    SciTech Connect

    Meagher, J.F.; Bailey, E.M.; Stockburger, L. III

    1981-03-01

    The Tennessee Valley Authority (TVA) has conducted several field experiments to examine the chemical interactions in isolated coal-fired power plant plumes, Particularly the conversion of sulfur dioxide (SO/sub 2/) to sulfate (SO/sub 4//sup 2 -/) aerosols. Six field studies have been conducted at three TVA power plants - Cumberland, paradise, and Colbert Steam Plants - each of which has a different boiler configuration. Studies were conducted during all seasons of the year. Samples were usually collected between sunrise and noon; however, at Cumberland and Paradise Steam Plants, samples were also collected in the afternoon and after sunset. The effect of several meteorological parameters on the conversion rate was investigated from the results of these studies. During one study at Cumberland Steam Plant, samples were taken during periods of reduced and normal electrostatic precipitator (ESP) operation; results from this study were used to investigate the effect of particle loading in the plume on the conversion rate.

  12. Magnetic fusion energy plasma interactive and high heat flux components. Volume III. Strategy for international collaborations in the areas of plasma materials interactions and high heat flux materials and components development

    SciTech Connect

    Gauster, W.B.; Bauer, W.; Roberto, J.B.; Post, D.E.

    1984-01-01

    The purpose of this summary is to assess opportunities for such collaborations in the specific areas of Plasma Materials Interaction and High Heat Flux Materials and Components Development, and to aid in developing a strategy to take advantage of them. After some general discussion of international collaborations, we summarize key technical issues and the US programs to address them. Then follows a summary of present collaborations and potential opportunities in foreign laboratories.

  13. STEALTH - a Lagrange explicit finite-difference code for solid, structural, and thermohydraulic analysis. Volume 8A: STEALTH/WHAMSE - a 2-D fluid-structure interaction code. Computer code manual

    SciTech Connect

    Gross, M.B.

    1984-10-01

    STEALTH is a family of computer codes that can be used to calculate a variety of physical processes in which the dynamic behavior of a continuum is involved. The version of STEALTH described in this volume is designed for calculations of fluid-structure interaction. This version of the program consists of a hydrodynamic version of STEALTH which has been coupled to a finite-element code, WHAMSE. STEALTH computes the transient response of the fluid continuum, while WHAMSE computes the transient response of shell and beam structures under external fluid loadings. The coupling between STEALTH and WHAMSE is performed during each cycle or step of a calculation. Separate calculations of fluid response and structural response are avoided, thereby giving a more accurate model of the dynamic coupling between fluid and structure. This volume provides the theoretical background, the finite-difference equations, the finite-element equations, a discussion of several sample problems, a listing of the input decks for the sample problems, a programmer's manual and a description of the input records for the STEALTH/WHAMSE computer program.

  14. Neutron diffraction study of the type I clathrate Ba8Al(x)Si(46-x): site occupancies, cage volumes, and the interaction between the guest and the host framework.

    PubMed

    Roudebush, John H; de la Cruz, Clarina; Chakoumakos, Bryan C; Kauzlarich, Susan M

    2012-02-01

    Samples with the type I clathrate structure and composition Ba(8)Al(x)Si(46-x), where x = 8, 10, 12, 14, and 15, were examined by neutron powder diffraction at 35 K. The clathrate type I structure contains Ba cations as guests in a framework derived from tetrahedrally coordinated Al/Si atoms. The framework is made up of five- and six-membered rings that form dodecahedral and tetrakaidecahedral cages. The change in distances between tetrahedral sites across the series is used to develop a model for the mixed Al/Si occupancy observed in the framework. The calculated volumes of the cages that contain the Ba atoms display a linear increase with increasing Al composition. In the smaller dodecahedral cages, the Ba atomic displacement parameter is symmetry constrained to be isotropic for all compositions. In the larger tetrakaidecahedral cages, the anisotropic atomic displacement of the Ba atom depends upon the composition: the displacement is perpendicular (x = 8) and parallel (x = 15) to the six-membered ring. This difference in direction of the displacement parameter is attributed to interaction with the Al in the framework and not to the size of the cage volume as x increases from 8 to 15. The influence of the site occupation of Al in the framework on displacement of the cation at the 6d site is demonstrated. PMID:22191511

  15. Comparisons of Sediment Test Volumes for Freshwater Solid Phase Sediment Toxicity Tests

    EPA Science Inventory

    Laboratory tests with benthic macroinvertebrates are commonly used to assess the potential toxicity of contaminated sediments, and detailed standard test procedures have been developed for various species. For freshwater, two benthic organisms, Hyalella azteca and Chironomus dil...

  16. 3-D patterns and volumes of decompression melting fueled by asthenospheric flow: comparison and interaction of shear-driven upwelling with small-scale convection

    NASA Astrophysics Data System (ADS)

    Ballmer, M. D.; Conrad, C. P.; Harmon, N.; Bianco, T. A.; Smith, E. I.

    2011-12-01

    asthenospheric shear and convective instability modulate the geometry of rheological heterogeneity. For decompression melting from these mechanisms, we present model predictions for volumes, patterns and source composition of intraplate volcanism in time and space. Timescales of volcanism are smaller for cases dominated by SDU and BMI and alignment with plate-motion is stronger for cases dominated by SSC and BMI. Our predictions are compared to the geologic record of continental and oceanic intraplate volcanism in the western US and the South Pacific. We further constrain our models by comparing model predictions for the mantle source of melting, and e.g. the geoid-to-topography ratio to geochemical and geophysical observables. Our results shed light on the origin of continental and oceanic intraplate volcanism, identify the relevant dynamic regimes for both these settings, and address the make-up and dynamics of the Earth's mantle.

  17. Magnetic Fusion Energy Plasma Interactive and High Heat Flux Components: Volume 5, Technical assessment of critical issues in the steady state operation of fusion confinement devices

    SciTech Connect

    Not Available

    1988-01-01

    Critical issues for the steady state operation of plasma confinement devices exist in both the physics and technology fields of fusion research. Due to the wide range and number of these issues, this technical assessment has focused on the crucial issues associated with the plasma physics and the plasma interactive components. The document provides information on the problem areas that affect the design and operation of a steady state ETR or ITER type confinement device. It discusses both tokamaks and alternative concepts, and provides a survey of existing and planned confinement machines and laboratory facilities that can address the identified issues. A universal definition of steady state operation is difficult to obtain. From a physics point of view, steady state is generally achieved when the time derivatives approach zero and the operation time greatly exceeds the characteristic time constants of the device. Steady state operation for materials depends on whether thermal stress, creep, fatigue, radiation damage, or power removal are being discussed. For erosion issues, the fluence and availability of the machine for continuous operation are important, assuming that transient events such as disruptions do not limit the component lifetimes. The panel suggests, in general terms, that steady state requires plasma operation from 100 to 1000 seconds and an availability of more than a few percent, which is similar to the expectations for an ETR type device. The assessment of critical issues for steady state operation is divided into four sections: physics issues; technology issues; issues in alternative concepts; and devices and laboratory facilities that can address these problems.

  18. Assessing Effects and interactions among key variables affecting the growth of mixotrophic microalgae: pH, inoculum volume, and growth medium composition.

    PubMed

    Ale, M T; Pinelo, M; Meyer, A S

    2014-01-01

    A 2(3) + 3 full factorial experimental design was used to evaluate growth rate and biomass productivity of four selected, high-biomass-yielding microalgae species,namely, Chlorella vulgaris (CV), Scenedesmus acutus (SA), Chlamydomonas reinhardtii (CR), and Chlamydomonas debaryana (CD), in mixtures of growth medium (MWC) and wastewater at different proportions (from 20 to 50% of MWC) and at different pH (from 7 to 9). Multilinear regression analysis of the biomass productivity data showed that for SA and CD the biomass productivity was independent of the proportion of medium (MWC), while the growth of CV and CR slowed down in mixtures with high proportions of wastewater. However, the biomass productivity of SA was dependent on pH, while the growth of the other microalgae was independent of pH (7-9). When evaluating the influence of pH and proportion of medium, CD appeared most robust among the algae species, despite its lower biomass productivity. All the four species reduced 80-90% of the nitrate [Formula: see text] and 60-70% of the ammonia [Formula: see text] initially present in the wastewater:medium mixture, although the extent of the reduction was dependent on the initial [Formula: see text] ratio. Both SA and CV reduced ∼20-25% of the chemical oxygen demand (COD) contained in the wastewater. This study shows the remarkable influence of certain variables that are often ignored in the search for optimal conditions of microalgal growth and also reveals the importance of considering interactions among growth variables in potential applications at large scale, particularly in the field of bioremediation. PMID:24274013

  19. Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations

    USGS Publications Warehouse

    Hay, M.B.; Stoliker, D.L.; Davis, J.A.; Zachara, J.M.

    2011-01-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ???1% of the solid volume and intragranular surface areas of ???20%-35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity. Copyright 2011 by the American Geophysical Union.

  20. Characterization of the intragranular water regime within subsurface sediments: pore volume, surface area, and mass transfer limitations

    USGS Publications Warehouse

    Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

    2011-01-01

    Although "intragranular" pore space within grain aggregates, grain fractures, and mineral surface coatings may contain a relatively small fraction of the total porosity within a porous medium, it often contains a significant fraction of the reactive surface area, and can thus strongly affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment procedure using tritiated water as a high-resolution diffusive tracer to characterize the intragranular pore space. The method was tested using uranium-contaminated sediments from the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site (Washington). Sediments were contacted with tracers in artificial groundwater, followed by a replacement of bulk solution with tracer-free groundwater and the monitoring of tracer release. From these data, intragranular pore volumes were calculated and mass transfer rates were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment that was vacuum dried after reaction. The complementary ("wet" and "dry") techniques allowed for the simultaneous determination of intragranular porosity and surface area using tritium. The Hanford 300A samples exhibited intragranular pore volumes of ~1% of the solid volume and intragranular surface areas of ~20%–35% of the total surface area. Analogous experiments using bromide ion as a tracer yielded very different results, suggesting very little penetration of bromide into the intragranular porosity.

  1. Strategic Plan. Volume 1

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The purpose of this document is to present the strategic plan and associated organizational structure that the National Space Biomedical Research Institute (NSBRI) will utilize to achieve the defined mission and objectives provided by NASA. Much of the information regarding the background and establishment of the NSBRI by NASA has been provided in other documentation and will not be repeated in this Strategic Plan. This Strategic Plan is presented in two volumes. Volume I (this volume) begins with an Introduction (Section 2) that provides the Institute's NASA-defined mission and objectives, and the organizational structure adopted to implement these through three Strategic Programs: Countermeasure Research; Education, Training and Outreach; and Cooperative Research and Development. These programs are described in Sections 3 to 5. Each program is presented in a similar way, using four subsections: Goals and Objectives; Current Strategies; Gaps and Modifications; and Resource Requirements. Section 6 provides the administrative infrastructure and total budget required to implement the Strategic Programs and assures that they form a single cohesive plan. This plan will ensure continued success of the Institute for the next five years. Volume II of the Strategic Plan provides an in-depth analysis of the current and future strategic programs of the 12 current NSBRI teams, including their goals, objectives, mutual interactions and schedules.

  2. Speaking Volumes

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2014-01-01

    Students love to talk. So do teachers. When there's a balance in the classroom between student and teacher discourse, good things happen. When students assume increased responsibility for discussions, when they interact with a wide range of peers on diverse topics and supply evidence for their thinking, great things happen. Noted educators…

  3. Direct Volume Rendering of Curvilinear Volumes

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi; Wilhelms, J.; Challinger, J.; Alper, N.; Ramamoorthy, S.; Kutler, Paul (Technical Monitor)

    1998-01-01

    Direct volume rendering can visualize sampled 3D scalar data as a continuous medium, or extract features. However, it is generally slow. Furthermore, most algorithms for direct volume rendering have assumed rectilinear gridded data. This paper discusses methods for using direct volume rendering when the original volume is curvilinear, i.e. is divided into six-sided cells which are not necessarily equilateral hexahedra. One approach is to ray-cast such volumes directly. An alternative approach is to interpolate the sample volumes to a rectilinear grid, and use this regular volume for rendering. Advantages and disadvantages of the two approaches in terms of speed and image quality are explored.

  4. Sparse PDF Volumes for Consistent Multi-Resolution Volume Rendering

    PubMed Central

    Sicat, Ronell; Krüger, Jens; Möller, Torsten; Hadwiger, Markus

    2015-01-01

    This paper presents a new multi-resolution volume representation called sparse pdf volumes, which enables consistent multi-resolution volume rendering based on probability density functions (pdfs) of voxel neighborhoods. These pdfs are defined in the 4D domain jointly comprising the 3D volume and its 1D intensity range. Crucially, the computation of sparse pdf volumes exploits data coherence in 4D, resulting in a sparse representation with surprisingly low storage requirements. At run time, we dynamically apply transfer functions to the pdfs using simple and fast convolutions. Whereas standard low-pass filtering and down-sampling incur visible differences between resolution levels, the use of pdfs facilitates consistent results independent of the resolution level used. We describe the efficient out-of-core computation of large-scale sparse pdf volumes, using a novel iterative simplification procedure of a mixture of 4D Gaussians. Finally, our data structure is optimized to facilitate interactive multi-resolution volume rendering on GPUs. PMID:26146475

  5. Anisotropic Ambient Volume Shading.

    PubMed

    Ament, Marco; Dachsbacher, Carsten

    2016-01-01

    We present a novel method to compute anisotropic shading for direct volume rendering to improve the perception of the orientation and shape of surface-like structures. We determine the scale-aware anisotropy of a shading point by analyzing its ambient region. We sample adjacent points with similar scalar values to perform a principal component analysis by computing the eigenvectors and eigenvalues of the covariance matrix. In particular, we estimate the tangent directions, which serve as the tangent frame for anisotropic bidirectional reflectance distribution functions. Moreover, we exploit the ratio of the eigenvalues to measure the magnitude of the anisotropy at each shading point. Altogether, this allows us to model a data-driven, smooth transition from isotropic to strongly anisotropic volume shading. In this way, the shape of volumetric features can be enhanced significantly by aligning specular highlights along the principal direction of anisotropy. Our algorithm is independent of the transfer function, which allows us to compute all shading parameters once and store them with the data set. We integrated our method in a GPU-based volume renderer, which offers interactive control of the transfer function, light source positions, and viewpoint. Our results demonstrate the benefit of anisotropic shading for visualization to achieve data-driven local illumination for improved perception compared to isotropic shading. PMID:26529745

  6. Volume Visual Attention Maps (VVAM) in ray-casting rendering.

    PubMed

    Beristain, Andoni; Congote, John; Ruiz, Oscar

    2012-01-01

    This paper presents an extension visual attention maps for volume data visualization, where eye fixation points become rays in the 3D space, and the visual attention map becomes a volume. This Volume Visual Attention Map (VVAM) is used to interactively enhance a ray-casting based direct volume rendering (DVR) visualization. The practical application of this idea into the biomedical image visualization field is explored for interactive visualization. PMID:22356956

  7. Time-Critical Volume Rendering

    NASA Technical Reports Server (NTRS)

    Kaufman, Arie

    1998-01-01

    For the past twelve months, we have conducted and completed a joint research entitled "Time- Critical Volume Rendering" with NASA Ames. As expected, High performance volume rendering algorithms have been developed by exploring some new faster rendering techniques, including object presence acceleration, parallel processing, and hierarchical level-of-detail representation. Using our new techniques, initial experiments have achieved real-time rendering rates of more than 10 frames per second of various 3D data sets with highest resolution. A couple of joint papers and technique reports as well as an interactive real-time demo have been compiled as the result of this project.

  8. Transparent volume imaging

    NASA Astrophysics Data System (ADS)

    Wixson, Steve E.

    1990-07-01

    Transparent Volume Imaging began with the stereo xray in 1895 and ended for most investigators when radiation safety concerns eliminated the second view. Today, similiar images can be generated by the computer without safety hazards providing improved perception and new means of image quantification. A volumetric workstation is under development based on an operational prototype. The workstation consists of multiple symbolic and numeric processors, binocular stereo color display generator with large image memory and liquid crystal shutter, voice input and output, a 3D pointer that uses projection lenses so that structures in 3 space can be touched directly, 3D hard copy using vectograph and lenticular printing, and presentation facilities using stereo 35mm slide and stereo video tape projection. Volumetric software includes a volume window manager, Mayo Clinic's Analyze program and our Digital Stereo Microscope (DSM) algorithms. The DSM uses stereo xray-like projections, rapidly oscillating motion and focal depth cues such that detail can be studied in the spatial context of the entire set of data. Focal depth cues are generated with a lens and apeture algorithm that generates a plane of sharp focus, and multiple stereo pairs each with a different plane of sharp focus are generated and stored in the large memory for interactive selection using a physical or symbolic depth selector. More recent work is studying non-linear focussing. Psychophysical studies are underway to understand how people perce ive images on a volumetric display and how accurately 3 dimensional structures can be quantitated from these displays.

  9. Basic Communication Course Annual. Volume 6.

    ERIC Educational Resources Information Center

    Newburger, Craig, Ed.

    This volume of an annual collection presents 14 essays relating to instruction in the basic communication course. Essays in the collection are "Using Interactive Video Instruction to Enhance Public Speaking Instruction" (Michael W. Cronin and William R. Kennan); "Interactive Video Instruction for Teaching Organizational Techniques in Public…

  10. Image plane sweep volume illumination.

    PubMed

    Sundén, Erik; Ynnerman, Anders; Ropinski, Timo

    2011-12-01

    In recent years, many volumetric illumination models have been proposed, which have the potential to simulate advanced lighting effects and thus support improved image comprehension. Although volume ray-casting is widely accepted as the volume rendering technique which achieves the highest image quality, so far no volumetric illumination algorithm has been designed to be directly incorporated into the ray-casting process. In this paper we propose image plane sweep volume illumination (IPSVI), which allows the integration of advanced illumination effects into a GPU-based volume ray-caster by exploiting the plane sweep paradigm. Thus, we are able to reduce the problem complexity and achieve interactive frame rates, while supporting scattering as well as shadowing. Since all illumination computations are performed directly within a single rendering pass, IPSVI does not require any preprocessing nor does it need to store intermediate results within an illumination volume. It therefore has a significantly lower memory footprint than other techniques. This makes IPSVI directly applicable to large data sets. Furthermore, the integration into a GPU-based ray-caster allows for high image quality as well as improved rendering performance by exploiting early ray termination. This paper discusses the theory behind IPSVI, describes its implementation, demonstrates its visual results and provides performance measurements. PMID:22034331

  11. Interactions between salt marsh plants and Cu nanoparticles - Effects on metal uptake and phytoremediation processes.

    PubMed

    Andreotti, Federico; Mucha, Ana Paula; Caetano, Cátia; Rodrigues, Paula; Rocha Gomes, Carlos; Almeida, C Marisa R

    2015-10-01

    The increased use of metallic nanoparticles (NPs) raises the probability of finding NPs in the environment. A lot of information exists already regarding interactions between plants and metals, but information regarding interactions between metallic NPs and plants, including salt marsh plants, is still lacking. This work aimed to study interactions between CuO NPs and the salt marsh plants Halimione portulacoides and Phragmites australis. In addition, the potential of these plants for phytoremediation of Cu NPs was evaluated. Plants were exposed for 8 days to sediment elutriate solution doped either with CuO or with ionic Cu. Afterwards, total metal concentrations were determined in plant tissues. Both plants accumulated Cu in their roots, but this accumulation was 4 to 10 times lower when the metal was added in NP form. For P. australis, metal translocation occurred when the metal was added either in ionic or in NP form, but for H. portulacoides no metal translocation was observed when NPs were added to the medium. Therefore, interactions between plants and NPs differ with the plant species. These facts should be taken in consideration when applying these plants for phytoremediation of contaminated sediments in estuaries, as the environmental management of these very important ecological areas can be affected. PMID:26094036

  12. Multivariate volume rendering

    SciTech Connect

    Crawfis, R.A.

    1996-03-01

    This paper presents a new technique for representing multivalued data sets defined on an integer lattice. It extends the state-of-the-art in volume rendering to include nonhomogeneous volume representations. That is, volume rendering of materials with very fine detail (e.g. translucent granite) within a voxel. Multivariate volume rendering is achieved by introducing controlled amounts of noise within the volume representation. Varying the local amount of noise within the volume is used to represent a separate scalar variable. The technique can also be used in image synthesis to create more realistic clouds and fog.

  13. Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations

    SciTech Connect

    Hay, Michael B.; Stoliker, Deborah L.; Davis, James A.; Zachara, John M.

    2011-10-29

    Although 'intragranular' pore space within grain aggregates, grain fractures, and mineral 24 surface coatings may contain a relatively small fraction of the total porosity within a porous 25 medium, it often contains a significant fraction of the reactive surface area, and can thus strongly 26 affect the transport of sorbing solutes. In this work, we demonstrate a batch experiment 27 procedure using tritium and bromide as high-resolution diffusive tracers to characterize the 28 intragranular pore space. The method was tested using uranium-contaminated sediments from 29 the vadose and capillary fringe zones beneath the former 300A process ponds at the Hanford site 30 (Washington State, USA). Sediments were contacted with tracers in artificial groundwater, 31 followed by replacement of bulk solution with tracer-free groundwater and monitoring of tracer 32 release. From these data, intragranular pore volumes were calculated and mass transfer rates 33 were quantified using a multirate first-order mass transfer model. Tritium-hydrogen exchange 34 on surface hydroxyls was accounted for by conducting additional tracer experiments on sediment 35 that was vacuum dried after reaction. The complementary ('wet' and 'dry') techniques allowed 36 for the simultaneous determination of intragranular porosity and surface area using tritium. The 37 Hanford 300A samples exhibited intragranular pore volumes of {approx}1% of the solid volume and 38 intragranular surface areas of {approx}20-30% of the total surface area. Comparison with N2 gas 39 adsorption suggests that this pore space includes both 'micropores' (< 2 nm diameter) and 40 'mesopores' (> 2 nm). Intragranular porosity estimates obtained using bromide were 41 significantly smaller, likely due to anion exclusion of Br- from pores with negatively charged 42 surfaces.

  14. Free Volume in Membranes: Viscosity or Tension?

    PubMed Central

    Markin, V. S.; Sachs, F.

    2016-01-01

    Many papers have used fluorescent probe diffusion to infer membrane viscosity but the measurement is actually an assay of the free volume of the membrane. The free volume is also related to the membrane tension. Thus, changes in probe mobility refer equally well to changes in membrane tension. In complicated structures like cell membranes, it appears more intuitive to consider variations in free volume as referring to the effect of domains structures and interactions with the cytoskeleton than changes in viscosity since tension is a state variable and viscosity is not.

  15. Astronautic Structures Manual, Volume 3

    NASA Technical Reports Server (NTRS)

    1975-01-01

    This document (Volumes I, II, and III) presents a compilation of industry-wide methods in aerospace strength analysis that can be carried out by hand, that are general enough in scope to cover most structures encountered, and that are sophisticated enough to give accurate estimates of the actual strength expected. It provides analysis techniques for the elastic and inelastic stress ranges. It serves not only as a catalog of methods not usually available, but also as a reference source for the background of the methods themselves. An overview of the manual is as follows: Section A is a general introduction of methods used and includes sections on loads, combined stresses, and interaction curves; Section B is devoted to methods of strength analysis; Section C is devoted to the topic of structural stability; Section D is on thermal stresses; Section E is on fatigue and fracture mechanics; Section F is on composites; Section G is on rotating machinery; and Section H is on statistics. These three volumes supersede Volumes I and II, NASA TM X-60041 and NASA TM X-60042, respectively.

  16. The effects of inlet turbulence and rotor/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model. Volume 2: Heat transfer data tabulation. 15 percent axial spacing

    NASA Technical Reports Server (NTRS)

    Dring, R. P.; Blair, M. F.; Joslyn, H. D.

    1986-01-01

    A combined experimental and analytical program was conducted to examine the effects of inlet turbulence on airfoil heat transfer. The experimental portion of the study was conducted in a large-scale (approx 5X engine), ambient temperature, rotating turbine model configured in both single stage and stage-and-a-half arrangements. Heat transfer measurements were obtained using low-conductivity airfoils with miniature thermcouples welded to a thin, electrically heated surface skin. Heat transfer data were acquired for various combinations of low or high inlet turbulence intensity, flow coefficient, first-stator/rotor axial spacing, Reynolds number and relative circumferential position of the first and second stators. Aerodynamic measurements obtained as part of the program include distributions of the mean and fluctuating velocities at the turbine inlet and, for each airfoil row, midspan airfoil surface pressures and circumferential distributions of the downstream steady state pressures and fluctuating velocities. Analytical results include airfoil heat transfer predictions produced using existing 2-D boundary layer computation schemes and an examination of solutions of the unsteady boundary layer equations. The results are reported in four separate volumes, of which this is Volume 2: Heat Transfer Data Tabulation; 15 Percent Axial Spacing.

  17. A Study of Interaction Effects of School and Home Environments on Students of Varying Race/Ethnicity, Class, and Gender. Final Report. Volume II: Ethnographies of Five Racial/Ethnic Groups.

    ERIC Educational Resources Information Center

    Herzog, John D.; And Others

    This report describes the ethnographic phase of a 2-year study (consisting of ethnographic observation and a survey) on how perceptions of home and school climates and interaction between the two factors might affect school performance among students of different racial/ethnic groups, sex, and socioeconomic status. Ethnographic case studies of…

  18. Monitoring and modelling of soil-plant interactions: the joint use of ERT, sap flow and eddy covariance data to characterize the volume of an orange tree root zone

    NASA Astrophysics Data System (ADS)

    Cassiani, G.; Boaga, J.; Vanella, D.; Perri, M. T.; Consoli, S.

    2015-05-01

    Mass and energy exchanges between soil, plants and atmosphere control a number of key environmental processes involving hydrology, biota and climate. The understanding of these exchanges also play a critical role for practical purposes e.g. in precision agriculture. In this paper we present a methodology based on coupling innovative data collection and models in order to obtain quantitative estimates of the key parameters of such complex flow system. In particular we propose the use of hydro-geophysical monitoring via "time-lapse" electrical resistivity tomography (ERT) in conjunction with measurements of plant transpiration via sap flow and evapotranspiration (ET) from eddy covariance (EC). This abundance of data is fed to spatially distributed soil models in order to characterize the distribution of active roots. We conducted experiments in an orange orchard in eastern Sicily (Italy), characterized by the typical Mediterranean semi-arid climate. The subsoil dynamics, particularly influenced by irrigation and root uptake, were characterized mainly by the ERT set-up, consisting of 48 buried electrodes on 4 instrumented micro-boreholes (about 1.2 m deep) placed at the corners of a square (with about 1.3 m long sides) surrounding the orange tree, plus 24 mini-electrodes on the surface spaced 0.1 m on a square grid. During the monitoring, we collected repeated ERT and time domain reflectometry (TDR) soil moisture measurements, soil water sampling, sap flow measurements from the orange tree and EC data. We conducted a laboratory calibration of the soil electrical properties as a function of moisture content and porewater electrical conductivity. Irrigation, precipitation, sap flow and ET data are available allowing for knowledge of the system's long-term forcing conditions on the system. This information was used to calibrate a 1-D Richards' equation model representing the dynamics of the volume monitored via 3-D ERT. Information on the soil hydraulic properties was

  19. Monitoring and modelling of soil-plant interactions: the joint use of ERT, sap flow and Eddy Covariance data to characterize the volume of an orange tree root zone

    NASA Astrophysics Data System (ADS)

    Cassiani, G.; Boaga, J.; Vanella, D.; Perri, M. T.; Consoli, S.

    2014-12-01

    Mass and energy exchanges between soil, plants and atmosphere control a number of key environmental processes involving hydrology, biota and climate. The understanding of these exchanges also play a critical role for practical purposes e.g. in precision agriculture. In this paper we present a methodology based on coupling innovative data collection and models in order to obtain quantitative estimates of the key parameters of such complex flow system. In particular we propose the use of hydro-geophysical monitoring via 4-D Electrical Resistivity Tomography (ERT) in conjunction with measurements of plant transpiration via sap flow and evapotranspiration from Eddy Covariance (EC). This abundance of data is fed to a spatially distributed soil model in order to characterize the distribution of active roots. We conducted experiments in an orange orchard in Eastern Sicily (Italy), characterized by the typical Mediterranean semi-arid climate. The subsoil dynamics, particularly influenced by irrigation and root uptake, were characterized mainly by the ERT setup, consisting of 48 buried electrodes on 4 instrumented micro boreholes (about 1.2 m deep) placed at the corners of a square (about 1.3 m in side) surrounding the orange tree, plus 24 mini-electrodes on the surface spaced 0.1 m on a square grid. During the monitoring, we collected repeated ERT and TDR soil moisture measurements, soil water samples, sap flow measurements from the orange tree and EC data. We conducted a laboratory calibration of the soil electrical properties as a function of moisture content and pore water electrical conductivity. Irrigation, precipitation, sap flow and ET data are available allowing knowledge of the system's long term forcing conditions on the system. This information was used to calibrate a 1-D Richards' equation model representing the dynamics of the volume monitored via 3-D ERT. Information on the soil hydraulic properties was collected from laboratory and field experiments. The

  20. WYSIWYG (What You See is What You Get) volume visualization.

    PubMed

    Guo, Hanqi; Mao, Ningyu; Yuan, Xiaoru

    2011-12-01

    In this paper, we propose a volume visualization system that accepts direct manipulation through a sketch-based What You See Is What You Get (WYSIWYG) approach. Similar to the operations in painting applications for 2D images, in our system, a full set of tools have been developed to enable direct volume rendering manipulation of color, transparency, contrast, brightness, and other optical properties by brushing a few strokes on top of the rendered volume image. To be able to smartly identify the targeted features of the volume, our system matches the sparse sketching input with the clustered features both in image space and volume space. To achieve interactivity, both special algorithms to accelerate the input identification and feature matching have been developed and implemented in our system. Without resorting to tuning transfer function parameters, our proposed system accepts sparse stroke inputs and provides users with intuitive, flexible and effective interaction during volume data exploration and visualization. PMID:22034329

  1. Presentation: Assessing Remedy Effectiveness of Contaminated Sediments using Brown Bullheads and Benthic macroinvertebrates to contaminated sediments in the Ashtabula River before, during and after dredging

    EPA Science Inventory

    The Ashtabula River in Northeastern, Ohio has been designated by the International Joint Commission as a Great Lakes Area of Concern (www.epa.gov/glnpo/aoc), based on the listing of six beneficial use impairments (out of 14 possible) in the lower two miles of the river. In 2007, ...

  2. The effects of inlet turbulence and rotor/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model. Volume 3: Heat transfer data tabulation 65 percent axial spacing

    NASA Technical Reports Server (NTRS)

    Dring, R. P.; Blair, M. F.; Joslyn, H. D.

    1986-01-01

    This is Volume 3 - Heat Transfer Data Tabulation (65 percent Axial Spacing) of a combined experimental and analytical program which was conducted to examine the effects of inlet turbulence on airfoil heat transfer. The experimental portion of the study was conducted in a large-scale (approximately 5X engine), ambient temperature, rotating turbine model configured in both single stage and stage-and-a-half arrangements. Heat transfer measurements were obtained using low-conductivity airfoils with miniature thermocouples welded to a thin, electrically heated surface skin. Heat transfer data were acquired for various combinations of low or high inlet turbulence intensity, flow coefficient, first-stator/rotor axial spacing, Reynolds number and relative circumferential position of the first and second stators.

  3. Adverse Drug Interactions

    PubMed Central

    Becker, Daniel E.

    2011-01-01

    The potential for interactions with current medications should always be considered when administering or prescribing any drug. Considering the staggering number of drugs patients may be taking, this task can be daunting. Fortunately, drug classes employed in dental practice are relatively few in number and therapy is generally brief in duration. While this reduces the volume of potential interactions, there are still a significant number to be considered. This article will review basic principles of drug interactions and highlight those of greatest concern in dental practice. PMID:21410363

  4. Nineteenth International Cosmic Ray Conference. OG Sessions, Volume 3

    NASA Technical Reports Server (NTRS)

    Jones, F. C. (Compiler)

    1985-01-01

    Papers submitted for presentation at the 19th International Cosmic Ray Conference are compiled. This volume addresses cosmic ray sources and acceleration, interstellar propagation and nuclear interactions, and detection techniques and instrumentation.

  5. Unsteady flow volumes

    SciTech Connect

    Becker, B.G.; Lane, D.A.; Max, N.L.

    1995-03-01

    Flow volumes are extended for use in unsteady (time-dependent) flows. The resulting unsteady flow volumes are the 3 dimensional analog of streamlines. There are few examples where methods other than particle tracing have been used to visualize time varying flows. Since particle paths can become convoluted in time there are additional considerations to be made when extending any visualization technique to unsteady flows. We will present some solutions to the problems which occur in subdivision, rendering, and system design. We will apply the unsteady flow volumes to a variety of field types including moving multi-zoned curvilinear grids.

  6. Variable-Volume Container

    NASA Technical Reports Server (NTRS)

    Colling, A. K.; Nallette, T. A.; Sansevero, F.

    1989-01-01

    Container holds bed of beads securely while accommodating sizable changes in volume and allowing gases to flow through bed. Developed for air-purifying system in which carbon dioxide is removed by solid amine beads.

  7. Environmental chemistry: Volume A

    SciTech Connect

    Yen, T.F.

    1999-08-01

    This is an extensive introduction to environmental chemistry for engineering and chemical professionals. The contents of Volume A include a brief review of basic chemistry prior to coverage of litho, atmo, hydro, pedo, and biospheres.

  8. Stereometric body volume measurement

    NASA Technical Reports Server (NTRS)

    Herron, R. E.

    1975-01-01

    The following studies are reported: (1) effects of extended space flight on body form of Skylab astronauts using biostereometrics; (2) comparison of body volume determinations using hydrostatic weighing and biostereometrics; and (3) training of technicians in biostereometric principles and procedures.

  9. Free volume under shear.

    PubMed

    Maiti, Moumita; Vinutha, H A; Sastry, Srikanth; Heussinger, Claus

    2015-10-14

    Using an athermal quasistatic simulation protocol, we study the distribution of free volumes in sheared hard-particle packings close to, but below, the random-close packing threshold. We show that under shear, and independent of volume fraction, the free volumes develop features similar to close-packed systems - particles self-organize in a manner as to mimick the isotropically jammed state. We compare athermally sheared packings with thermalized packings and show that thermalization leads to an erasure of these structural features. The temporal evolution in particular the opening-up and the closing of free-volume patches is associated with the single-particle dynamics, showing a crossover from ballistic to diffusive behavior. PMID:26472384

  10. Geomagnetism. Volume I

    SciTech Connect

    Jacobs, J.A.

    1987-01-01

    The latest attempt to summarise the wealth of knowledge now available on geomagnetic phenomena has resulted in this multi-volume treatise, with contributions and reviews from many scientists. The first volume in the series contains a thorough review of all existing information on measuring the Earth's magnetic field, both on land and at sea, and includes a comparative analysis of the techniques available for this purpose.

  11. TREATABILITY MANUAL. VOLUME V: SUMMARY

    EPA Science Inventory

    The Treatability Manual presents in five volumes an extensive survey of the effectiveness of various water pollution treatment processes when applied to particular industrial effluents. This volume summarizes volumes one through four and outlines their potential utility to Nation...

  12. Exploded views for volume data.

    PubMed

    Bruckner, Stefan; Gröiller, M Eduard

    2006-01-01

    Exploded views are an illustration technique where an object is partitioned into several segments. These segments are displaced to reveal otherwise hidden detail. In this paper we apply the concept of exploded views to volumetric data in order to solve the general problem of occlusion. In many cases an object of interest is occluded by other structures. While transparency or cutaways can be used to reveal a focus object, these techniques remove parts of the context information. Exploded views, on the other hand, do not suffer from this drawback. Our approach employs a force-based model: the volume is divided into a part configuration controlled by a number of forces and constraints. The focus object exerts an explosion force causing the parts to arrange according to the given constraints. We show that this novel and flexible approach allows for a wide variety of explosion-based visualizations including view-dependent explosions. Furthermore, we present a high-quality GPU-based volume ray casting algorithm for exploded views which allows rendering and interaction at several frames per second. PMID:17080837

  13. Coulomb interactions and fermion condensation

    SciTech Connect

    Capstick, S.; Cutkosky, R.E.; Joensen, M.A. ); Wang, K.C. )

    1990-08-15

    The influence of the Coulomb interaction in states containing massless and flavorless fermion-antifermion pairs is studied, using a continuum formulation within the finite volume {ital S}{sup 3}. Several different forms for the Coulomb interaction are examined, including confining potentials as well as nonconfining potentials. The calculations show that if the interaction is strong enough, the Coulomb interaction leads to condensation of pairs, and that this condensation has a chiral character. The condensation does not depend on whether the interaction is confining. It is found that simplified variational approximations are not accurate enough for an adequate description of the states.

  14. Volume MLS ray casting.

    PubMed

    Ledergerber, Christian; Guennebaud, Gaël; Meyer, Miriah; Bächer, Moritz; Pfister, Hanspeter

    2008-01-01

    The method of Moving Least Squares (MLS) is a popular framework for reconstructing continuous functions from scattered data due to its rich mathematical properties and well-understood theoretical foundations. This paper applies MLS to volume rendering, providing a unified mathematical framework for ray casting of scalar data stored over regular as well as irregular grids. We use the MLS reconstruction to render smooth isosurfaces and to compute accurate derivatives for high-quality shading effects. We also present a novel, adaptive preintegration scheme to improve the efficiency of the ray casting algorithm by reducing the overall number of function evaluations, and an efficient implementation of our framework exploiting modern graphics hardware. The resulting system enables high-quality volume integration and shaded isosurface rendering for regular and irregular volume data. PMID:18988986

  15. Assessing volume status.

    PubMed

    Scott, Michael C; Mallemat, Haney

    2014-11-01

    Shock is a physiologic state associated with high morbidity and mortality rates. The clinician has several tools available to evaluate volume status. Each modality has its benefits and limitations but, to date, no one test can indicate with 100% accuracy which patients will be truly volume responsive. Although the search for the Holy Grail of a perfect intravascular monitor continues, we must remember the importance of early, aggressive, and goal-directed interventions for patients in shock. Finally, there is no substitute for the most important intervention-the frequent presence of the physician at the patient's bedside. PMID:25441036

  16. Aperiodic Volume Optics

    NASA Astrophysics Data System (ADS)

    Gerke, Tim D.

    Presented in this thesis is an investigation into aperiodic volume optical devices. The three main topics of research and discussion are the aperiodic volume optical devices that we call computer-generated volume holograms (CGVH), defects within periodic 3D photonic crystals, and non-periodic, but ordered 3D quasicrystals. The first of these devices, CGVHs, are designed and investigated numerically and experimentally. We study the performance of multi-layered amplitude computer-generated volume holograms in terms of efficiency and angular/frequency selectivity. Simulation results show that such aperiodic devices can increase diffraction efficiency relative to periodic amplitude volume holograms while maintaining angular and wavelength selectivity. CGVHs are also designed as voxelated volumes using a new projection optimization algorithm. They are investigated using a volumetric diffraction simulation and a standard 3D beam propagation technique as well as experimentally. Both simulation and experiment verify that the structures function according to their design. These represent the first diffractive structures that have the capacity for generating arbitrary transmission and reflection wave fronts and that provide the ability for multiplexing arbitrary functionality given different illumination conditions. Also investigated and discussed in this thesis are 3D photonic crystals and quasicrystals. We demonstrate that these devices can be fabricated using a femtosecond laser direct writing system that is particularly appropriate for fabrication of such arbitrary 3D structures. We also show that these devices can provide 3D partial bandgaps which could become complete bandgaps if fabricated using high index materials or by coating lower index materials with high index metals. Our fabrication method is particularly suited to the fabrication of engineered defects within the periodic or quasi-periodic systems. We demonstrate the potential for fabricating defects within

  17. Time varying, multivariate volume data reduction

    SciTech Connect

    Ahrens, James P; Fout, Nathaniel; Ma, Kwan - Liu

    2010-01-01

    Large-scale supercomputing is revolutionizing the way science is conducted. A growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. The data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. Transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. Although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. In this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. Two configurations for multidimensional compression based on vector quantization are examined. We emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering. In this paper we present a solution which addresses the need for data reduction in large supercomputing environments where data resulting from simulations occupies tremendous amounts of storage. Our solution employs a lossy encoding scheme to acrueve data reduction with several options in terms of rate-distortion behavior. We focus on encoding of multiple variables together, with optional compression in space and time. The compressed volumes can be rendered directly with commodity graphics cards at interactive frame rates and rendering quality similar to that of static volume renderers. Compression results using a multivariate time-varying data set indicate that encoding multiple variables results in acceptable performance in the case of spatial and temporal encoding as compared to independent compression of variables. The relative performance of spatial vs. temporal compression is data dependent, although temporal compression has the

  18. Runtime volume visualization for parallel CFD

    NASA Technical Reports Server (NTRS)

    Ma, Kwan-Liu

    1995-01-01

    This paper discusses some aspects of design of a data distributed, massively parallel volume rendering library for runtime visualization of parallel computational fluid dynamics simulations in a message-passing environment. Unlike the traditional scheme in which visualization is a postprocessing step, the rendering is done in place on each node processor. Computational scientists who run large-scale simulations on a massively parallel computer can thus perform interactive monitoring of their simulations. The current library provides an interface to handle volume data on rectilinear grids. The same design principles can be generalized to handle other types of grids. For demonstration, we run a parallel Navier-Stokes solver making use of this rendering library on the Intel Paragon XP/S. The interactive visual response achieved is found to be very useful. Performance studies show that the parallel rendering process is scalable with the size of the simulation as well as with the parallel computer.

  19. GREEK BASIC COURSE, VOLUME I.

    ERIC Educational Resources Information Center

    OBOLENSKY, SERGE; AND OTHERS

    THE GREEK LANGUAGE DESCRIBED IN VOLUME I OF THIS INTRODUCTORY COURSE FOR ADULTS IS THE "KATHOMILUMENI" VARIETY, THAT OF THE STANDARD SPEECH OF EDUCATED GREEKS. (VOLUME III OF THE COURSE INTRODUCES THE MORE FORMAL KATHAREVUSA VARIETY.) EACH VOLUME OF THE COURSE CONTAINS 25 UNITS PLUS FIVE REVIEW SECTIONS. A TYPICAL UNIT IN VOLUME I CONSISTS OF--(1)…

  20. Seismic engineering -- 1996. PVP-volume 340

    SciTech Connect

    Saleem, M.A.; Aggarwal, M.C.

    1996-12-01

    The 37 papers in this volume have been arranged under the following topical sections: advanced methods in seismic engineering (7 papers); high level dynamic response of piping systems (5); equipment seismic qualification (6); soil structure interaction (3); advanced seismic technology in Asian countries (8); developments in seismic codes and standards (8); and a panel discussion on the review of current issues by the Special Working Group on seismic rules. Papers have been processed separately for inclusion on the data base.

  1. Progress in nonhistone protein research. Volume II

    SciTech Connect

    Bekhor, I.

    1985-01-01

    This volume focuses on how nonhistones participate in the control of gene function, and provides information on HMG proteins, specific nuclear antigens, a specific phosphoprotein, salt soluble and insoluble nonhistones, hormone interactions with DNA, nonhistones with enzyme functions, nonhistones binding carcinogens, and Epstein-Barr nuclear antigen. The nuclear matrix salt insoluble nonhistones, methods for analysis of nonhistones in both normal and malignant cells, and the use of monoclonal antibodies to study functions of nonhistones are examined.

  2. Progress in nonhistone protein research. Volume I

    SciTech Connect

    Bekhor, I.

    1985-01-01

    This volume focuses on how nonhistones participate in the control of gene function, and provides information on HMG proteins, specific nuclear antigens, a specific phosphoprotein, salt soluble and insoluble nonhistones, hormone interactions with DNA, nonhistones with enzyme functions, nonhistones binding carcinogens, and Epstein-Barr nuclear antigen. The nuclear matrix salt insoluble nonhistones, methods for analysis of nonhistones in both normal and malignant cells, and the use of monoclonal antibodies to study functions of nonhistones are examined.

  3. Leadership Abstracts, Volume 10.

    ERIC Educational Resources Information Center

    Milliron, Mark D., Ed.

    1997-01-01

    The abstracts in this series provide brief discussions of issues related to leadership, administration, professional development, technology, and education in community colleges. Volume 10 for 1997 contains the following 12 abstracts: (1) "On Community College Renewal" (Nathan L. Hodges and Mark D. Milliron); (2) "The Community College Niche in a…

  4. Liter - Metric Volume.

    ERIC Educational Resources Information Center

    Sisk, Diane

    This autoinstructional program, developed as part of a general science course, is offered for students in the middle schools. Mathematics of fractions and decimals is considered to be prerequisite knowledge. The behavioral objectives are directed toward mastery of determining volumes of solid objects using the water displacement method as well as…

  5. Overview of the Volume

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Emslie, A. G.; Hudson, H. S.

    2011-01-01

    In this introductory chapter, we provide a brief summary of the successes and remaining challenges in understanding the solar flare phenomenon and its attendant implications for particle acceleration mechanisms in astrophysical plasmas. We also provide a brief overview of the contents of the other chapters in this volume, with particular reference to the well-observed flare of 2002 July 23.

  6. Volume measuring system

    NASA Technical Reports Server (NTRS)

    Oele, J. S.

    1975-01-01

    Chamber is designed to be airtight; it includes face mask for person to breathe outside air so that he does not disturb chamber environment. Chamber includes piston to vary air volume inside. Also included are two microphone transducers which record pressure information inside chamber.

  7. Navajo Biographies. Volume I.

    ERIC Educational Resources Information Center

    Hoffman, Virginia

    The life stories of eight Navajo ("Dine", their term for themselves) leaders are presented in volume one of this collection of biographies. Interspersed with portraits, drawings, and maps, the narrative chronologically covers the time period from 1766 when the Navajos lived on land under the rule of Spain into the twentieth century and dealings…

  8. VOLUME AND SURFACE AREA.

    ERIC Educational Resources Information Center

    FOLEY, JACK L.

    THIS BOOKLET, ONE OF A SERIES, HAS BEEN DEVELOPED FOR THE PROJECT, A PROGRAM FOR MATHEMATICALLY UNDERDEVELOPED PUPILS. A PROJECT TEAM, INCLUDING INSERVICE TEACHERS, IS BEING USED TO WRITE AND DEVELOP THE MATERIALS FOR THIS PROGRAM. THE MATERIALS DEVELOPED IN THIS BOOKLET INCLUDE (1) MEASURING VOLUMES OF RECTANGULAR SOLIDS, RIGHT RECTANGULAR…

  9. Negotiating Salaries, Volume II.

    ERIC Educational Resources Information Center

    Educational Service Bureau, Inc., Washington, DC.

    This volume discusses specific strategy and tactics that can be employed in the effort to reach an agreement on salaries at the bargaining table. Although strategies and situations may vary from case to case, this report focuses on those principles and approaches that are essential to any good bargaining procedure. The discussion covers public vs.…

  10. Negotiating Salaries, Volume I.

    ERIC Educational Resources Information Center

    Educational Service Bureau, Inc., Washington, DC.

    This volume deals with concepts important to the effective negotiation of salaries in public schools. The discussion covers the compensation patterns in education, the goals and pressures affecting reacher negotiators, salaries in relation to other benefits and proposals, extra pay for extra duties and merit pay, and the stance of the negotiators…

  11. Results of test MA22 in the NASA/LaRC 31-inch CFHT on an 0.010-scale model (32-0) of the space shuttle configuration 3 to determine RCS jet flow field interaction, volume 1. [wind tunnel tests for interactions of aerodynamic heating on jet flow

    NASA Technical Reports Server (NTRS)

    Kanipe, D. B.

    1976-01-01

    A wind tunnel test was conducted in the Langley Research Center 31-inch Continuous Flow Hypersonic Wind Tunnel from May 6, 1975 through June 3, 1975. The primary objectives of this test were the following: (1) to study the ability of the wind tunnel to repeat, on a run-to-run basis, data taken for identical configurations to determine if errors in repeatability could have a significant effect on jet interaction data, (2) to determine the effect of aerodynamic heating of the scale model on jet interaction, (3) to investigate the effects of elevon and body flap deflections on jet interaction, (4) to determine if the effects from jets fired separately along different axes can be added to equal the effects of the jets fired simultaneously (super position effects), (5) to study multiple jet effects, and (6) to investigate area ratio effects, i.e., the effect on jet interaction measurements of using wind tunnel nozzles with different area ratios in the same location. The model used in the test was a .010-scale model of the Space Shuttle Orbiter Configuration 3. The test was conducted at Mach 10.3 and a dynamic pressure of 150 psf. RCS chamber pressure was varied to simulate free flight dynamic pressures of 5, 7.5, 10, and 20 psf.

  12. Powerful Interactions

    ERIC Educational Resources Information Center

    Dombro, Amy Laura; Jablon, Judy R.; Stetson, Charlotte

    2011-01-01

    Interactions are the daily exchanges in words and gestures one has with others. As a teacher, the interactions he/she has with young children can make a positive difference in their lives. A teacher's powerful interactions with children play an important role in their emotional well-being and learning. Powerful interactions are not the same as…

  13. Global bioconversions. Volume 2

    SciTech Connect

    Wise, D.L.

    1987-01-01

    These volumes present the most active bioconversion-based research and development projects worldwide, with an emphasis on the important practical aspects of this work. A major focus of the text is the bioconversion of organic residues to useful products, which also encompasses the field of anaerobic methane fermentation. Chapters from an international perspective are also included, which further address the global importance of bioconversion.

  14. Global bioconversions. Volume 4

    SciTech Connect

    Wise, D.L.

    1987-01-01

    These volumes present the most active bioconversion-based research and development projects worldwide, with an emphasis on the important practical aspects of this work. A major focus of the text is the bioconversion of organic residues to useful products, which also encompasses the field of anaerobic methane fermentation. Chapters from an international perspective are also included, which further address the global importance of bioconversion.

  15. Variable volume calibration apparatus

    SciTech Connect

    Hallman, R.L. Jr.

    1991-01-01

    An apparatus is provided for determining the volume of a closed chamber. The apparatus includes a body having a cylindrical cavity therein including a threaded rear portion and a closed front end, and a piston having a threaded portion which mates with threaded rear portion of the cavity and which reciprocates in the cavity. A gas-impermeable seal, which is carried by the piston in one embodiment, forms a closed chamber in the front end of the cavity. A linear-movement indicator, attached to the rear end of the piston, measures the reciprocating movement of the piston in the cavity, while a pressure sensing device, connected to the front end of the cavity, determines the pressure in the closed system. In use, a vessel, having a volume enclosing experimental materials, is also connected to the front end of the cavity, and pressure and piston movement measurements are made which enable calculation of a volume change in the vessels. The design and operation of this instrument are presented. 7 figs.

  16. Research Summary No. 36-6, Volume II. Volume II

    NASA Technical Reports Server (NTRS)

    1961-01-01

    The Research Summary is a bimonthly report of supporting research and development conducted at the Jet Propulsion Laboratory. This periodical is issued in three volumes. Volume I contains summaries of the work accomplished by the Space Sciences, Systems, Guidance and Control, and Telecommunications Divisions of the Laboratory. Volume II contains summaries of the work accomplished by the Physical Sciences, Engineering Mechanics, Engineering Facilities, and Propulsion Divisions. All work of a classified nature is contained in Volume Ill.

  17. Research Summary No. 36-5, Volume II. Volume II

    NASA Technical Reports Server (NTRS)

    1960-01-01

    The Research Summary is a bimonthly report of supporting research and development conducted at the Jet Propulsion Laboratory. This periodical is issued in three volumes. Volume I contains summaries of the work accomplished by the Space Sciences, Systems, Guidance and Control, and Telecommunications Divisions of the Laboratory. Volume II contains summaries of the work accomplished by the Physical Sciences, Engineering Mechanics, Engineering Facilities, and Propulsion Divisions. All work of a classified nature is contained in Volume Ill.

  18. Size dependence of cavity volume: a molecular dynamics study.

    PubMed

    Patel, Nisha; Dubins, David N; Pomès, Régis; Chalikian, Tigran V

    2012-02-01

    Partial molar volume, V°, has been used as a tool to sample solute hydration for decades. The efficacy of volumetric investigations of hydration depends on our ability to reliably discriminate between the cavity, V(C), and interaction, V(I), contributions to the partial molar volume. The cavity volume, V(C), consists of the intrinsic volume, V(M), of a solute molecule and the thermal volume, V(T), with the latter representing the volume of the effective void created around the solute. In this work, we use molecular dynamics simulations in conjunction with the Kirkwood-Buff theory to compute the partial molar volumes for organic solutes of varying sizes in water. We perform our computations using the Lennard-Jones and Coulombic pair potentials as well as truncated potentials which contain only the Lennard-Jones but not the Coulombic contribution. The partial molar volume computed with the Lennard-Jones potentials in the absence of the Coulombic term nearly coincides with the cavity volume, V(C). We determine the thermal volume, V(T), for each compound by subtracting its van der Waals volume, V(W), from V(C). Finally, we apply the spherical approximation of solute geometry to evaluate the thickness of the thermal volume, δ. Our results reveal an increase in the thickness of thermal volume, δ, with an increase in the size of the solute. This finding may be related to dewetting of large nonpolar solutes and the concomitant increase in the compressibility of water of hydration. PMID:22133917

  19. UTILIZATION OF BIOREMEDIATION PROCESSES FOR THE TREATMENT OF PAH-CONTAMINATED SEDIMENTS. (R825513C020)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  20. Bioleaching of multiple heavy metals from contaminated sediment by mesophile consortium.

    PubMed

    Gan, Min; Zhou, Shuang; Li, Mingming; Zhu, Jianyu; Liu, Xinxing; Chai, Liyuan

    2015-04-01

    A defined mesophile consortium including Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirilum ferriphilum was applied in bioleaching sediments contaminated with multiple heavy metals. Flask experiments showed that sulfur favored the acidification in the early stage while pyrite led to a great acidification potential in the later stage. An equal sulfur/pyrite ratio got the best acidification effect. Substrate utilization started with sulfur in the early stage, and then the pH decline and the community shift give rise to the utilization of pyrite. Solubilization efficiency of Zn, Cu, Mn, and Cd reached 96.1, 93.3, 92.13, and 87.65%, respectively. Bioleaching efficiency of other elements (As, Hg, Pb) was not more than 30%. Heavy metal solubilization was highly negatively correlated with pH variation. Logistic models were well fitted with the solubilization efficiency, which can be used to predict the bioleaching process. The dominant species in the early stage of bioleaching were A. ferrooxidans and A. thiooxidans, and the abundance of L. ferriphilum increased together with pyrite utilization and pH decline. PMID:25384695

  1. Multispecies toxicity assessment of compost produced in bioremediation of an explosives-contaminated sediment

    SciTech Connect

    Gunderson, C.A.; Napolitano, G.E.; Wicker, L.F.; Richmond, J.E.; Stewart, A.J.; Kostuk, J.M.; Gibbs, M.H.

    1997-12-01

    A multispecies terrestrial test system was used to assess the environmental effectiveness of composting for bioremediation of explosives-contaminated soils. The assessment involved comparing biological responses, from the individual to the community level, in remediated and reference composts. A 6-month greenhouse study incorporated two soil invertebrate species, three plant species and an associated symbiont, and the naturally occurring complement of soil microorganisms. Measured parameters included growth and reproduction of earthworms and isopods; soil mote diversity; soil lipid class composition as an indicator of soil microbial community structure; plant growth, photosynthesis, and reproduction; and root nodulation and symbiotic N{sub 2} fixation. Additional short-term toxicity tests of seed germination and earthworm survival were performed to supplement the mesocosm data. Compost prepared from the explosives-contaminated soil inhibited several aspects of plant growth and physiology, but few adverse effects on soil invertebrates were detected. An initial lag in earthworm and isopod reproduction occurred in the reference compost, reflecting some inherent compost differences not associated with contamination, and highlighting the importance and the difficulty of finding appropriate reference soils for assessing hazardous waste sites or remediation technologies. Nonetheless, the results from this study suggested some nonlethal effects from the contaminated-soil compost, primarily to plants. The mesocosm methodology used in this study can bridge the gap between traditional short-term toxicity testing and longer term field assessments, and provide information on ecological effects by explicitly including measurements of multiple species across several levels of ecological organization.

  2. Dissimilatory Sb(V) reduction by microorganisms isolated from Sb-contaminated sediment

    NASA Astrophysics Data System (ADS)

    Dovick, M. A.; Kulp, T. R.

    2013-12-01

    Mining and smelting are major sources of trace metal contamination in freshwater systems. Arsenic (As) is a common contaminant derived from certain mining operations and is a known toxic metalloid and carcinogen. Antimony (Sb) is listed as a pollutant of priority interest by the EPA and is presumed to share similar geochemical and toxicological properties with arsenic. Both elements can occur in four different oxidation states (V, III, 0, and -III) under naturally occurring conditions. In aqueous solutions As(V) and Sb(V) predominate in oxygenated surface waters whereas As(III) and Sb(III) are stable in anoxic settings. Numerous studies have examined microbiological redox pathways that utilize As(V) as a terminal electron acceptor for anaerobic respiration, however there have been few studies on microbial mechanisms that may affect the biogeochemical cycling of Sb in the environment. Here we report bacterial reduction of Sb(V) to Sb(III) in anoxic enrichment cultures and bacterial isolates grown from sediment collected from an Sb contaminated pond at a mine tailings site in Idaho (total pond water Sb concentration = 235.2 +/- 136.3 ug/L). Anaerobic sediment microcosms (40 mL) were established in artificial freshwater mineral salt medium, amended with millimolar concentrations of Sb(V), acetate or lactate, and incubated at 27°C for several days. Antimony(V), lactate, and acetate concentrations were monitored during incubation by High Performance Liquid Chromatography (HPLC) and Ion Chromatography (IC). Live sediment microcosms reduced millimolar amendments of Sb(V) to Sb(III) coupled to the oxidation of acetate and lactate, while no activity occurred in killed controls. Enrichment cultures were established by serially diluting Sb(V)-reducing microcosms in mineral salt medium with Sb(V) and acetate, and a Sb(V)-reducing bacterial strain was isolated by plating on anaerobic agar plates amended with millimolar Sb(V) and acetate. Direct cell counting demonstrated that this isolate exhibited Sb(V)-dependent heterotrophic growth. These results suggest that the endogenous microbial community from this Sb-contaminated site includes anaerobic microorganisms capable of obtaining energy for growth by oxidizing heterotrophic electron donors using Sb(V) as the terminal electron acceptor. Ongoing work includes identification of the isolated organism using 16S rDNA phylogenetic markers as well as an inventory of known functional genes (e.g., arrA) within this isolate that may more typically encode for As(V)-reduction. These results elucidate the potentially significant role of microbiological transformations in controlling the speciation of Sb in the environment, and may help to identify potential bioremediation strategies for Sb contaminated waters.

  3. Lead poisoning of waterfowl by contaminated sediment in the Coeur d'Alene River.

    PubMed

    Sileo, L; Creekmore, L H; Audet, D J; Snyder, M R; Meteyer, C U; Franson, J C; Locke, L N; Smith, M R; Finley, D L

    2001-10-01

    The Coeur d'Alene River basin in Idaho has been contaminated by mine tailings that have impaired the health of wildlife since the early 1900s. In other parts of the world, virtually all lead poisoning of waterfowl is caused by the ingestion of manmade lead artifacts, primarily spent lead shotshell pellets or, occasionally, fishing sinkers. However, in the Coeur d'Alene River basin in Idaho, nonartifactual lead poisoning was the ultimate cause of death of most of 219 (77%) of 285 waterfowl carcasses that had been found sick or dead from 1992 through 1997. The majority of these 219 waterfowl (172 tundra swans [Cygnus columbianus], 33 Canada geese [Branta canadensis], and 14 other species) were poisoned by ingesting river sediment that was contaminated with lead. The next most common cause of death (20 instances, 7%) was lead poisoning accompanied by ingested shotshell pellets. The remaining 46 waterfowl succumbed to trauma, infectious diseases (aspergillosis, avian cholera, tuberculosis), or miscellaneous problems, or the cause of death was not determined. PMID:11503074

  4. Tracing the dispersion of contaminated sediment with plutonium isotope measurements in coastal catchments of Fukushima Prefecture

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Pointurier, Fabien; Onda, Yuichi; Chartin, Caroline; Hubert, Amélie; Lepage, Hugo; Pottin, Anne-Claire; Lefèvre, Irène; Bonté, Philippe; Laceby, J. Patrick; Ayrault, Sophie

    2015-04-01

    The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to important releases of radionuclides into the environment, and trace levels of plutonium (Pu) were detected in northeastern Japan. However, measurement of Pu isotopic atom and activity ratios is required to differentiate between the contributions of global nuclear test fallout and FDNPP emissions. In this study, we measured Pu isotopic ratios in recently deposited sediments along rivers draining the most contaminated part of the inland radioactive plume. To this end, we carried out a thorough chemical purification and concentration of Pu from sediment samples (5 g dry material) and precise isotopic measurements using a double-focusing sector field ICP-MS. Results showed that the entire range of measured Pu isotopes (i.e., 239Pu, 240Pu, 241Pu, and 242Pu) were detected in all samples, although in extremely low concentrations. The 241Pu/239Pu atom ratios measured in sediment deposits (0.0017-0.0884) were significantly higher than the corresponding values attributed to the global fallout (0.00113±0.00008 on average in the Northern Hemisphere between 31°-71°N). The results indicated the presence of Pu from FDNPP, in slight excess compared to the Pu background from global fallout, representing up to ca. 60% of Pu in the analyzed samples. These results demonstrate that this radionuclide has been transported relatively long distances (45 km) from FDNPP and deposited in rivers representing a potential source of Pu to the ocean.

  5. PREDICTION OF CONTAMINATED SEDIMENT TRANSPORT IN THE MAURICE RIVER-UNION LAKE, NEW JERSEY, USA

    EPA Science Inventory

    A sediment and contaminant transport model and its application to the Maurice River-Union Lake system in southern New Jersey, USA is described. The application is meant to characterize and forecast sediment and arsenic (As) distributions before and after proposed dredging activit...

  6. PREDICTION OF CONTAMINATED SEDIMENT TRANSPORT IN THE MAURICE RIVER-UNION LAKE, NEW JERSEY, USA

    EPA Science Inventory

    This paper describes a sediment and contaminant transport model and its application to the Maurice River-Union Lake system in southern New Jersey, USA for the purpose of characterizing and forecasting sediment and arsenic distributions before and after proposed dredging activitie...

  7. ASSESSING THE BIOAVAILABILITY OF PAHS IN FIELD-CONTAMINATED SEDIMENT USING XAD-2 ASSISTED DESORPTION

    EPA Science Inventory

    In the bioremediation of soils/sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) it is imperative to determine the fraction of the PAHs that is amenable to remediation. For example, what fraction of the PAHs is available to the indigenous microorganisms, i.e. bi...

  8. Bioremediation of Trichloroethylene-Contaminated Sediments Augmented with a Dehalococcoides Consortia

    SciTech Connect

    McKinsey, P.C.

    2003-02-20

    At the Department of Energy's (DOE) Savannah River Site (SRS) in Aiken, SC there are a number of sites contaminated with Chlorinated Ethenes (CE) due to past disposal practices. Sediments from two CE contaminated SRS locations were evaluated for trichloroethylene (TCE) biodegradation through anaerobic laboratory microcosms. The testing included addition of amendments and bioaugmentation of sediments. The anaerobic microcosms were first amended with substrates including acetate, lactate, molasses, soybean oil, methanol, sulfate, yeast extract, Regenesis HRC(R), and MEAL (methanol, ethanol, acetate, lactate mixture). Microcosms were analyzed after biostimulation for 9 months and no significant TCE biodegradation was observed. At 10 months, additional TCE, fresh amendments, and a mixed culture containing Dehalococcoides ethenogenes were added to active microcosms. A significant decrease in TCE concentrations and an increase in biodegradation products cis-dichloroethylene (cDCE) and vinyl chloride (VC) were noted within 2 weeks of bioaugmentation. Microcosms amended with lactate and sulfate showed complete transformation of TCE (3 ppm) to ethene within 40 days after bioaugmentation. Microcosms amended with other substrates - soybean oil, acetate, yeast extract, and methanol - also show enhanced biodegradation of TCE to ethene. Microcosms amended with molasses and Regenesis HRC showed limited TCE transformation. No TCE transformation was seen in killed control microcosms. On the basis of these successful results, plans are underway for field-scale in-situ deployment of biostimulation/bioaugmentation at SRS.

  9. PCB concentration in fish in a river system after remediation of contaminated sediment

    SciTech Connect

    Bremle, G.; Larsson, P.

    1998-11-15

    An 1991 investigation of PCB concentrations in water and fish along a river was repeated in 1996 after the completion of a remediation of PCB-containing sediment in a lake within the river system. The PCB concentrations in the lake water decreased significantly, and the concentrations in fish was halved (significantly lower) after remediation. PCB still remaining in littoral sediment was probably the cause for a recorded gradient of PCB concentrations in fish from the lake and downstream. The PCB concentrations in water and fish was lower in 1996 compared to 1991 in all locations studied. The decreased levels of PCB in fish between the years for the two upstream locations, probably results from a decline in background PCB exposure. Monitoring data from 30 years back, recorded in a south Swedish lake, has shown a 5% decline per year in the PCB concentration in pike. The data on PCB concentration in fish from the two upstream locations were recalculated on the basis of this yearly decline and resulted in concentrations close to those measured in 1996. The results indicated, that changes in background exposure must be taken into account when evaluating the success of remedial actions measures carried out over several years.

  10. Modeling polychlorinated biphenyl mass transfer after amendment of contaminated sediment with activated carbon

    SciTech Connect

    David Werner; Upal Ghosh; Richard G. Luthy

    2006-07-01

    The sorption kinetics and concentration of polychlorinated biphenyls (PCBs) in historically polluted sediment is modeled to assess a remediation strategy based on in situ PCB sequestration by mixing with activated carbon (AC). The authors extend their evaluation of a model based on intraparticle diffusion by including a biomimetic semipermeable membrane device (SPMD) and a first-order degradation rate for the aqueous phase. The model predictions are compared with the previously reported experimental PCB concentrations in the bulk water phase and in SPMDs. The simulated scenarios comprise a marine and a freshwater sediment, four PCB congeners, two AC grain sizes, four doses of AC, and comparison with laboratory experiments. The modeling approach distinguishes between two different sediment particles types: a light-density fraction representing carbonaceous particles such as charcoal, coal, coke, cenospheres, or wood, and a heavy-density fraction representing the mineral phase with coatings of organic matter. A third particle type in the numerical model is AC. The model qualitatively reproduces the observed shifts in the PCB distribution during repartitioning after AC amendment but overestimates the overall effect of the treatment in reducing aqueous and SPMD concentrations of PCBs by a factor of 2-6. For the AC application in sediment, competitive sorption of the various solutes apparently requires a reduction by a factor of 16 of the literature values for the AC-water partitioning coefficient measured in pure aqueous systems. With this correction, model results and measurements agree within a factor of 3. After AC amendment is homogeneously mixed into the sediment and then left undisturbed, aqueous PCB concentrations tend toward the same reduction after 5 years. 19 refs., 5 figs., 4 tabs.

  11. Teratogenic and genotoxic responses of larval Chironomus (Diptera) to contaminated sediments

    SciTech Connect

    Hudson, L.A.; Muir, K.; Ciborowski, J.J.H.

    1994-12-31

    Sediment-associated contaminants can produce developmental or genotoxic stresses independently of their cytotoxic effects. In the laboratory, the authors exposed Chironomus larvae to mixtures of polluted (either Detroit R., MI, or cadmium or benzo-[a]-pyrene-spiked) sediment diluted with uncontaminated, formulated sediment. Second-instar Chironomus nr. salinarius were grown to 4th star in water filled 1-L jars containing 300 mL of contaminated:formulated sediment mixture in ratios of 1:0, 1:1, 1:3, 1:7, 1:15 or 0:1. Surviving larvae were preserved in Carnoy`s solution. Each larva`s head was slide-mounted and examined for deformities of the mentum. Polytene chromosome preparations were made from salivary glands of the same animals using acid fuschin staining and examined for reduced relative size of the nuclear organizer (NO) indicative of inhibition of RNA synthesis activity. Incidence of chironomid deformities from control (0:1) sediments ({plus_minus}I SE) was 7.9 {plus_minus} 1.6% (N = 268): 4.0 {plus_minus} 1.5% of 178 control larvae examined displayed NO reduction. Incidence of mentum deformities and of NO reduction increased linearly with each doubling of Detroit R. concentration at 1:0 for deformities; 12.2 {plus_minus} 3.5% (N = 149) for NO reductions. Reduction of NO in a larva was unrelated to mentum condition, indicating that these are independent responses to contaminant stress. Equivalent results were obtained for exposure to single-compound sediments. This is the first documentation of controlled dose-response effects of contaminants on chironomid deformities.

  12. EVALUATION OF A FLUOROMETRIC SCREENING METHOD FOR PREDICTING TOTAL PAH CONCENTRATIONS IN CONTAMINATED SEDIMENTS

    EPA Science Inventory

    A flurorometric screening method was used to estimate total polycyclic aromatic hydrocarbon concentrations in sediments collected from the St. Louis River Area of Concern in northeastern Minnesota. Sediments were collected as part of a Regional Environmental Monitoring and Asses...

  13. Passive Sampling Methods for Contaminated Sediments: Practical Guidance for Selection, Calibration, and Implementation

    EPA Science Inventory

    This article provides practical guidance on the use of passive sampling methods(PSMs) that target the freely dissolved concentration (Cfree) for improved exposure assessment of hydrophobic organic chemicals in sediments. Primary considerations for selecting a PSM for a specific a...

  14. Lead poisoning of waterfowl by contaminated sediment in the Coeur D'Alene River

    USGS Publications Warehouse

    Sileo, L.; Creekmore, L.H.; Audet, D.J.; Snyder, M.R.; Meteyer, C.U.; Franson, J.C.; Locke, L.N.; Smith, M.R.; Finley, D.L.

    2001-01-01

    The Coeur d'Alene River basin in Idaho has been contaminated by mine tailings that have impaired the health of wildlife since the early 1900s. In other parts of the world, virtually all lead poisoning of waterfowl is caused by the ingestion of manmade lead artifacts, primarily spent lead shotshell pellets or, occasionally, fishing sinkers. However, in the Coeur d'Alene River basin in Idaho, nonartifactual lead poisoning was the ultimate cause of death of most of 219 (77%) of 285 waterfowl carcasses that had been found sick or dead from 1992 through 1997. The majority of these 219 waterfowl (172 tundra swans [Cygnus columbianus], 33 Canada geese [Branta canadensis], and 14 other species) were poisoned by ingesting river sediment that was contaminated with lead. The next most common cause of death (20 instances, 7%) was lead poisoning accompanied by ingested shotshell pellets. The remaining 46 waterfowl succumbed to trauma, infectious diseases (aspergillosis, avian cholera, tuberculosis), or miscellaneous problems, or the cause of death was not determined.

  15. A Feasibility Study On Pd/Mg Application In Historically Contaminated Sediments And PCB Spiked Substrates

    EPA Science Inventory

    A vast majority of literature on bimetals deals with aqueous contaminants, very little being on organics strongly adsorbed on sediments and hence very challenging to remediate. Having previously reported materials, mechanistic and parametric aspects of PCB dechlorination with Pd...

  16. BIODEGRADATION OF SEDIMENT-BOUND PAHS IN FIELD-CONTAMINATED SEDIMENT

    EPA Science Inventory

    The biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been reported to occur under aerobic, sulfate reducing, and denitrifying conditions. PAHs present in contaminated sites, however, are known for their persistence. Most published studies were conducted in systems wh...

  17. STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

    EPA Science Inventory

    The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

  18. STABLE CHLORINE ISOTOPIC COMPOSITIONS OF AROCLORS AND ARCLOR-CONTAMINATED SEDIMENT

    EPA Science Inventory

    An exploratory investigation was conducted to evaluate if stable chlorine isotopic ratios of polychlorinated biphenyls (PCBs) could be useful in studying the processes that determine their transport and fate in the environment. First, we determined the variability of 37Cl in the...

  19. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans (journal version)

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-01-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund-site soils on freshwater invertebrates. These two species were used successfully in acute sediment tests and were shown to be useful in chronic tests in water.

  20. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-10-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund site soils on freshwater invertebrates. These two species have been used successfully in acute sediment tests, and have been shown to be useful in chronic tests in water--only bioassays.

  1. Assessing sediment connectivity to understand dynamics of contaminated sediment within coastal catchments of Fukushima Prefecture (Japan)

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    The Fukushima Dai-ichi Nuclear Power Plant accident has led to the release of large radionuclide quantities (e.g., about 20 PBq of Cs-137 and 200 PBq of I-131) into the atmosphere. About 80% of the release was blown out and over the Pacific Ocean. The remaining 20% of emissions were deposited as wet and dry deposits on soils of Fukushima Prefecture, mainly between 15-16 March. As most radionuclides are strongly sorbed by fine particles, they are likely to be redistributed within the landscape in association with soil and sediment particles transported by runoff and erosion processes. A spatial analysis of Ag-110m:Cs-137 ratio in soils and river sediments provided a way to trace those transfers. This fingerprinting study showed that particles eroded from inland mountain ranges exposed to the highest initial radionuclide fallout were already dispersed along coastal rivers, most likely during summer typhoons and spring snowmelt. Those results suggest that hillslopes and rivers have become a perennial source of radioactive contaminants to the Pacific Ocean off Fukushima Prefecture. This study aims to specify the location and nature of the preferential sources supplying contaminated material to the main rivers draining the Fukushima contamination plume. To this end, important parameters controlling soil erosion and sediment transfers within catchments, i.e. landscape morphology and land use characteristics, were preliminary derived from DEM data and satellite images for the River Mano, Nitta and Ota catchments (ca. 525 km²) draining the most radioactive part of the contamination plume that formed across Fukushima Prefecture. Then, those data were used to compute indices assessing the potential sediment connectivity (i) between hillslopes and rivers and (ii) between hillslopes and catchment outlets. Finally, spatially-distributed values of connectivity indices were confronted to gamma-emitting radionuclide activities (Cs-134, Cs-137 and Ag-110m) measured in riverbed sediment samples collected in November 2011, March 2012 and November 2012 just after the main hydro-sedimentary events that occurred in this region (i.e., summer typhoon and spring snowmelt). Preliminary results show that preferential contamination sources come from areas located near the river valleys, especially cultivated and built-up areas. However, forested zones even located on footslopes and convex settings appear to contribute significantly. Moreover, dams played a crucial role in controlling the contamination export to the Pacific Ocean. Those first results have important implications for the management of contaminated areas and dam reservoirs in the Fukushima Prefecture.

  2. A tiered assessment framework to evaluate human health risk of contaminated sediment.

    PubMed

    Greenfield, Ben K; Melwani, Aroon R; Bay, Steven M

    2015-07-01

    For sediment contaminated with bioaccumulative pollutants (e.g., PCBs and organochorine pesticides), human consumption of seafood that contain bioaccumulated sediment-derived contaminants is a well-established exposure pathway. Historically, regulation and management of this bioaccumulation pathway has focused on site-specific risk assessment. The state of California (United States) is supporting the development of a consistent and quantitative sediment assessment framework to aid in interpreting a narrative objective to protect human health. The conceptual basis of this framework focuses on 2 key questions: 1) do observed pollutant concentrations in seafood from a given site pose unacceptable health risks to human consumers? and 2) is sediment contamination at a site a significant contributor to seafood contamination? The first question is evaluated by interpreting seafood tissue concentrations at the site, based on health risk calculations. The second question is evaluated by interpreting site-specific sediment chemistry data using a food web bioaccumulation model. The assessment framework includes 3 tiers (screening assessment, site assessment, and refined site assessment), which enables the assessment to match variations in data availability, site complexity, and study objectives. The second and third tiers use a stochastic simulation approach, incorporating information on variability and uncertainty of key parameters, such as seafood contaminant concentration and consumption rate by humans. The framework incorporates site-specific values for sensitive parameters and statewide values for difficult to obtain or less sensitive parameters. The proposed approach advances risk assessment policy by incorporating local data into a consistent region-wide problem formulation, applying best available science in a streamlined fashion. PMID:25641876

  3. Microbial communities in contaminated sediments, associated with bioremediation of uranium to submicromolar levels

    SciTech Connect

    Cardenas, Erick; Wu, Weimin; Leigh, Mary Beth; Carley, Jack M; Carroll, Sue L; Gentry, Terry; Luo, Jian; Watson, David B; Gu, Baohua; Ginder-Vogel, Matthew A.; Kitanidis, Peter K.; Jardine, Philip M; Zhou, Jizhong; Criddle, Craig; Marsh, Terence; Tiedje, James M.

    2008-03-01

    Microbial enumeration, 16S rRNA gene clone libraries, and chemical analysis were used to evaluate the in situ biological reduction and immobilization of uranium(VI) in a long-term experiment (more than 2 years) conducted at a highly uranium-contaminated site (up to 60 mg/liter and 800 mg/kg solids) of the U.S. Department of Energy in Oak Ridge, TN. Bioreduction was achieved by conditioning groundwater above ground and then stimulating growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria in situ through weekly injection of ethanol into the subsurface. After nearly 2 years of intermittent injection of ethanol, aqueous U levels fell below the U.S. Environmental Protection Agency maximum contaminant level for drinking water and groundwater (<30 {micro}g/liter or 0.126 {micro}M). Sediment microbial communities from the treatment zone were compared with those from a control well without biostimulation. Most-probable-number estimations indicated that microorganisms implicated in bioremediation accumulated in the sediments of the treatment zone but were either absent or in very low numbers in an untreated control area. Organisms belonging to genera known to include U(VI) reducers were detected, including Desulfovibrio, Geobacter, Anaeromyxobacter, Desulfosporosinus, and Acidovorax spp. The predominant sulfate-reducing bacterial species were Desulfovibrio spp., while the iron reducers were represented by Ferribacterium spp. and Geothrix spp. Diversity-based clustering revealed differences between treated and untreated zones and also within samples of the treated area. Spatial differences in community structure within the treatment zone were likely related to the hydraulic pathway and to electron donor metabolism during biostimulation.

  4. In-Situ Survival Mechanisms of U and Tc Reducing Bacteria in Contaminated Sediments

    SciTech Connect

    Krumholz, Lee R.

    2005-06-01

    Desulfovibrio desulfuricans G20 and Shewanella oneidensis MR-1 are model subsurface organisms for studying genes involving in situ radionuclide transformation and sediment survival. Our research objective for this project has been to develop a signature-tagged mutagenesis (STM) procedure and use it to identify mutants in genes of these subsurface bacteria involved in sediment survival and radionuclide reduction. The mutant genes identified in these studies allow us for the first time to describe at the genetic level microbial processes that are actually being used by environmental bacteria while growing in their natural ecosystems. Identification of these genes revealed facets of microbial physiology and ecology that are not accessible through laboratory studies. Ultimately, this information may be used to optimize bioremediation or other engineered microbial processes. Furthermore, the identification of a mutant in a gene conferring multidrug resistance in strain MR-1 shows that this widespread mechanism of antibiotic resistance, likely has its origins as a mechanism of bacterial defense against naturally occurring toxins. Studies with D. desulfuricans G20: The STM procedure first involved generating a library of 5760 G20 mutants and screening for potential non-survivors in subsurface sediment microcosms. After two rounds of screening, a total of 117 mutants were confirmed to be true non-survivors. 97 transposon insertion regions have been sequenced to date. Upon further analysis of these mutants, we classified the sediment survival genes into COG functional categories. STM mutant insertions were located in genes encoding proteins related to metabolism (33%), cellular processes (42%), and information storage and processing (17%). We also noted 8% of STM mutants identified had insertions in genes for hypothetical proteins or unknown functions. Interestingly, at least 64 of these genes encode cytoplasmic proteins, 46 encode inner membrane proteins, and only 7 encode periplasmic space and outer membrane associated proteins. Through blast search analysis, we also showed that 81 out of 94 proteins shown to be important in sediment survival have homologs in D. vulgaris, 70 have homologs in Geobacter metallireducens, and 69 have homologs in Geobacter sulfurreducens PCA. Some interesting proteins include ribonucleotide reductase and chemotaxis related proteins. Ribonucleotide reductase catalyzes the reductive synthesis of deoxyribonucleotides from their corresponding ribonucleotides, providing the precursors necessary for DNA synthesis. Two ribonucleotide reductase genes (nrdE, nrdD) were found to be essential for G20 survival in the sediment, but not essential for growth in the lactate-sulfate medium. Bacterial methyl-accepting chemotaxis proteins (MCP) respond to changes in the concentration of attractants and repellents in the environment.

  5. Phytoremediation Of Mercury And Methylmercury Contaminated Sediments By Water Hyacinth (Eichhornia crassipes)

    EPA Science Inventory

    Phytoremediation has potential to be implemented at mercury (Hg) and methylmercury (MeHg) contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associated f...

  6. SCREENING PLANT SPECIES FOR GROWTH ON WEATHERED, PETROLEUM HYDROCARBON-CONTAMINATED SEDIMENTS. (R825413)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Bench-Scale Investigation Of Mercury Phytoremediation By Water Hyacinths (Eichhornia crassipes) In Heavily Contaminated Sediments

    EPA Science Inventory

    Phytoremediation has the potential to be implemented at mercury (Hg) and methylmercury (MeHg) contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associat...

  8. Phytoremediation of Mercury- and Methyl Mercury-Contaminated Sediments by Water Hyacinth (Eichhornia crassipes)

    EPA Science Inventory

    Phytoremediation has the potential for implementation at Hg- (Hg) and methylHg (MeHg)-contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associated forms...

  9. Bacterial Mercury Methylation At The Sediment-Water Interface Of Mercury Contaminated Sediments

    EPA Science Inventory

    Bench scale experiments were conducted to improve our understanding of bacterial mediation of mercury transformation (methylation), specifically those factors which govern the production of methyl mercury (MeHg) at the sediment-water interface. The greatest cause for concern re...

  10. Differences in oxidative stress between young Canada geese and mallards exposed to lead-contaminated sediment

    USGS Publications Warehouse

    Mateo, R.; Hoffman, D.J.

    2001-01-01

    Lead (Pb) exposure causes an increase in tissue lipid peroxides and variation in glutathione (GSH) concentration, which can be related to peroxidative damage of cell membranes in Pb poisoned animals. Species and individual variation in sensitivity to Pb poisoning among animals may be due to differential resistance to oxidative stress. We compared the effects of oxidative stress caused by Pb exposure (1.7, 414 and 828 ig/g of diet) for the first six weeks in growing young of two species of waterfowl, Canada geese (Branta canadensis) and mallards (Anas platyrhynchos), with the first species being possibly more sensitive to Pb poisoning based on previous field and laboratory observations. Blood and liver Pb concentrations increased more in mallards than in geese; this may be explained on the basis of body weight, being 3.2 times higher in geese, and hepatic metabolism where GSH-S-transferase activity is 2.9 fold higher in geese and presumably has a role in the binding of Pb to GSH and subsequent biliary excretion. In contrast, mallards showed higher hepatic levels of GSH and activities of GSH peroxidase (GPX) and GSH reductase (GR). Although both species showed an increase in hepatic GSH concentration with Pb exposure, the increase of lipid peroxidation with Pb exposure was more significant in geese. Within treatment groups, hepatic GSH concentrations were inversely related to liver Pb concentration in both species, which may correspond to the role of GSH in Pb excretion. Hepatic GSH was also inversely related to hepatic lipid peroxidation, but only in mallards and in agreement with the differences observed in GPX and GR activities. The lower resistance to lipid peroxidation of Canada geese may explain why birds of this species found dead in the field by Pb shot ingestion often have a lower number of shot in the gizzard and lower liver Pb concentrations than mallards.

  11. An evaluation of the toxicity of contaminated sediments from Waukegan Harbor, Illinois, following remediation

    USGS Publications Warehouse

    Kemble, N.E.; Hardesty, D.G.; Ingersoll, C.G.; Johnson, B.T.; Dwyer, F.J.; MacDonald, D.D.

    2000-01-01

    Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox?? were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar Contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site. Though the sediments were generally not lethal, there were still sublethal effects of contaminants in sediments at this site observed on amphipods in long-term exposures (associated with elevated concentrations of metals, PCBs, and PAHs).

  12. IN-SITU STRATEGIES FOR THE SEQUESTRATION OF ZINC IN CONTAMINATED SEDIMENTS

    EPA Science Inventory

    The application of in-situ remediation strategies for the sequestration of zinc is being studied as an alternative to the traditional method of excavation and containment. The site of study is the Indian Head Naval Warfare Center (IHNWC) located adjacent to Mattawoman Creek in Ch...

  13. EPA'S FIELD DEMONSTRATION OF INNOVATIVE CAPPING TECHNOLOGIES FOR THE RISK MANAGEMENT OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Research on capping technologies is directed at assessing the effectiveness of innovative capping materials, factors that control contaminant release at the sediment-water interface, installation of cap, resuspension mechanism, and gas ebullition. U.S. EPA's Land Remediation and ...

  14. Long-term autonomous resistivity monitoring of oil-contaminated sediments from the Deepwater Horizon spill

    NASA Astrophysics Data System (ADS)

    Heenan, J. W.; Slater, L. D.; Ntarlagiannis, D.; Atekwana, E. A.; Ross, C.; Nolan, J. T.; Atekwana, E. A.; Werkema, D. D.; Fathepure, B.

    2012-12-01

    We conducted a long-term electrical resistivity survey at Grand Terre 1 (GT1) Island off the coast of Louisiana, a site contaminated with crude oil associated with the April 2010 BP Deepwater Horizon oil spill. Electrical resistivity has proven sensitivity to biogeochemical processes associated with the biodegradation of hydrocarbons in the subsurface. However, most of these studies have been in freshwater environments and for aged spills. The BP Deepwater Horizon oil spill therefore provided an unprecedented opportunity to capture the early time biogeophysical signals resulting from the physical, chemical and microbial transformation of crude oil in highly saline environments. We used a multi-channel resistivity system powered by solar panels to obtain continuous measurements twice a day on both a surface array and two shallow borehole arrays. This system operated for approximately 1.5 years and provided a unique long-term dataset of resistivity changes. Temperature and specific conductance values for the shallow groundwater were continuously logged. . Resistivity changes likely associated with biodegradation processes were then isolated from these environmental factors by modeling. In addition, groundwater was sampled for geochemical analyses from wells installed at the study site and soil samples were collected for microbial analyses at several locations, including both contaminated and uncontaminated locations. Microcosms were set up to determine the biodegradation potential of indigenous populations, and microbial diversity analysis was used to determine microbial community composition. Surface and borehole resistivity arrays revealed an initial resistive anomaly co-located with the known contamination. Pixel time series analysis of an inverted time sequence of resistivity sections highlighted differing responses between contaminated and uncontaminated locations. The contaminated locations exhibit persistent resistivity decreases over time, whereas areas outside of the contaminated location exhibit relatively uniform resistivity or show clear evidence of seasonal effect. Temperature-corrected resistivity changes show no direct correlation with pore fluid specific conductance changes, suggesting that specific conductance changes (e.g. due to tides) have little influence on imaged resistivity structure. Microbial data suggest that resistivity changes within the contaminated location resulted from biodegradation, showing the presence of native populations capable of degrading aromatic hydrocarbons at salinities ranging from 6 to 15 % NaCl within the contaminated location. Aqueous geochemical measurements performed on samples from the site further indicate that at depth intervals coincident with the resistivity anomaly, marked increases in the concentration of dissolved inorganic carbon (DIC) were observed suggesting biodegradation of petroleum hydrocarbon although other DIC generating processes such as organic matter degradation coupled to sulfate and iron reduction were also prominent. This experiment demonstrates the potential viability of long-term autonomous electrical monitoring as a means of decreasing the frequency of more costly and invasive chemical analysis of natural attenuation.

  15. Bioavailability of polycyclic aromatic hydrocarbons from a historically contaminated sediment core

    SciTech Connect

    Harkey, G.A.; Van Hoof, P.L.; Landrum, P.F.

    1995-09-01

    To determine changes in bioavailability of selected polycyclic aromatic hydrocarbons (PAHs) with sediment aging, Lumbriculus variegatus were exposed for 4 weeks to sediment core sections taken from a contaminated lake. Core depths included surficial (0 to 4 cm), 4- to 8-, 12- to 16-, 28- to 32-, and 44- to 48-cm sections deposited for approximately 1899 to 1993, and were known to be historically contaminated with PAHs. Bioaccumulation was maximal at the 12- to 16-cm depth (circa 1967) where sediment PAH concentrations were greatest. Accumulation was generally below detection limits in the 0- to 4-cm depths, even though sediment concentrations of some compounds were comparable to those at the 12- to 16-cm depth where accumulation was great enough to generate accurate kinetics curves. Accumulation peaked at about 96 h, then declined over the remainder of the study for the lower-molecular-weight PAHs. For most higher-molecular-weight PAHs, accumulation peaked at about 2 weeks, then declined only slightly after 4 weeks. The differential bioavailability observed between surficial and at-depth core sections raises questions concerning the adequacy of results generated from toxicity and bioaccumulation tests routinely conducted surficial sediments.

  16. TOXICITY OF CREOSOTE-CONTAMINATED SEDIMENT TO FIELD-AND LABORATORY-COLONIZED ESTUARINE BENTHIC COMMUNITIES

    EPA Science Inventory

    Macrobenthic animal communities that colonized uncontaminated and creosote-contaminated sand during 8 weeks were compared to assess effects of marine-grade creosote on community structure. Aquaria were colonized in the laboratory by planktonic larvae entrained in continuously sup...

  17. Vadose zone microbial community structure and activity in metal/radionuclide contaminated sediments. Final technical report

    SciTech Connect

    Balkwill, David L.

    2002-08-17

    This final technical report describes the research carried out during the final two months of the no-cost extension ending 11/14/01. The primary goals of the project were (1) to determine the potential for transformation of Cr(VI) (oxidized, mobile) to Cr(III) (reduced, immobile) under unsaturated conditions as a function of different levels and combinations of (a) chromium, (b) nitrate (co-disposed with Cr), and (c) molasses (inexpensive bioremediation substrate), and (2) to determine population structure and activity in experimental treatments by characterization of the microbial community by signature biomarker analysis and by RT-PCR and terminal restriction fragment length polymorphism (T-RFLP) and 16S ribosomal RNA genes. It was determined early in the one-year no-cost extension period that the T-RFLP approach was problematic in regard to providing information on the identities of microorganisms in the samples examined. As a result, it could not provide the detailed information on microbial community structure that was needed to assess the effects of treatments with chromium, nitrate, and/or molasses. Therefore, we decided to obtain the desired information by amplifying (using TR-PCR, with the same primers used for T-RFLP) and cloning 16S rRNA gene sequences from the same RNA extracts that were used for T-RFLP analysis. We also decided to use a restriction enzyme digest procedure (fingerprinting procedure) to place the clones into types. The primary focus of the research carried out during this report period was twofold: (a) to complete the sequencing of the clones, and (b) to analyze the clone sequences phylogenetically in order to determine the relatedness of the bacteria detected in the samples to each other and to previously described genera and species.

  18. EVIDENCE FOR MICROBIAL ENHANCED ELECTRICAL CONDUCTIVITY IN HYDROCARBON-CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Electrical conductivity of sediments during microbial mineralization of diesel was investigated in a mesoscale column experiment consisting of biotic contaminated and uncontaminated columns. Microbial population numbers increased with a clear pattern of depth zonation within the ...

  19. Effects of lead-contaminated sediment and nutrition on mallard duckling brain growth and biochemistry

    USGS Publications Warehouse

    Douglas-Stroebel, E.; Hoffman, D.J.; Brewer, G.L.; Sileo, L.

    2004-01-01

    Day-old mallard (Anas platyryhnchos) ducklings received either a clean sediment (24%) supplemented control diet, Coeur d'Alene River Basin, Idaho (CDARB) sediment (3449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet) for 6 weeks. The 12% CDARB diet resulted in a geometric mean concentration of 396 ppb (WW) brain lead with decreased brain protein and ATP concentrations but increased oxidized glutathione (GSSG) relative to the control diet. The 24% CDARB diet resulted in a concentration of 485 ppb brain lead with lower brain weight and ATP concentration than controls but higher concentrations of reduced glutathione (GSH) and calcium. Lead acetate accumulated twice as well as CDARB derived lead and resulted in histopathological lesions of the brain. With a combination of a suboptimal diet and 24% CDARB, brain lead concentration was higher (594 ppb) than with 24% CDARB in the standard diet, histopathological lesions became apparent and GSH was higher than suboptimal diet controls.

  20. Effects of lead-contaminated sediment and nutrition on mallard duckling brain growth and biochemistry

    USGS Publications Warehouse

    Douglas-Stroebel, E.; Hoffman, D.J.; Brewer, G.L.; Sileo, L.

    2004-01-01

    Day-old mallard (Anas platyryhnchos) ducklings received either a clean sediment (24%) supplemented control diet, Coeur d'Alene River Basin, Idaho (CDARB) sediment (3449 ug/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet) for 6 weeks. The 12% CDARB diet resulted in a geometric mean concentration of 396 ppb (WW) brain lead with decreased brain protein and ATP concentrations but increased oxidized glutathione (GSSG) relative to the control diet. The 24% CDARB diet resulted in a concentration of 485 ppb brain lead with lower brain weight and ATP concentration than controls but higher concentrations of reduced glutathione (GSH) and calcium. Lead acetate accumulated twice as well as CDARB derived lead and resulted in histopathological lesions of the brain. With a combination of a suboptimal diet and 24% CDARB, brain lead concentration was higher (594 ppb) than with 24% CDARB in the standard diet, histopathological lesions became apparent and GSH was higher than suboptimal diet controls.

  1. Deciphering Microbial Carbon Sources in Petroleum Contaminated Sediments Using Compound Specific Radiocarbon Analysis

    NASA Astrophysics Data System (ADS)

    Morrill, P. L.; Szponar, N.; Maunder, C.; Marvin, C.; Slater, G. F.

    2008-12-01

    Microbial membrane phospholipid fatty acids (PLFAs) were analyzed to investigate microbial carbon sources and assess the impact of petroleum hydrocarbon contamination in one of North America's most contaminated harbours. Sediment cores were sampled from two locations in the harbour: a highly impacted area, Dofasco Boat Slip; and a less impacted area, Carole's Bay. Natural organic matter (NOM) and total petroleum hydrocarbons (TPHs) were two possible organic carbon sources for microbial metabolisms. While the majority of organic carbon (OC) at both Dofasco and Carole's Bay was NOM, petroleum hydrocarbons also contributed to the OC. As expected, the concentration of the TPHs was much greater at the Dofasco site (270 ug/g) compared to the TPHs concentration measured at Carole's Bay (50 ug/g). However, the % of PAHs that contributed to TPHs was very similar in the first three centimeters at both sites (9%). The PLFAs distributions at Carole's Bay and Dofasco were fairly similar indicating an overall bulk similarity between the communities notwithstanding higher contaminant concentrations at the Dofasco site. PLFA distributions changed with depth, consistent with changes in redox conditions from oxic to anoxia. The PLFAs extracted from the upper 3 cm of sediment from Carole's Bay had modern cap delta 14C values (with an average value of -66 ) compared to both the NOM (cap delta 14C -132 ) and TPH (cap delta 14C -775 ), suggesting that the carbon substrate for microbial metabolisms was a younger more labile source. The cap delta 14C isotopic values between individual PLFAs were indistinguishable (within the standard error of 20 for accuracy and reproducibility) demonstrating that if TPHs were degraded the impact on the cap delta 14C was not resolvable at Carole's Bay. Co-metabolic degradation of petroleum hydrocarbons is one possible degradation mechanism whereby biodegradation is occurring, but the contaminant carbon may not be incorporated into the microbial membrane PLFAs. Pure culture studies are being preformed to test this hypothesis. Data collected from Dofasco will be compared to the data from Carole's Bay.

  2. Assessing Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    EPA Science Inventory

    In this study, methods and approaches were developed and tested to assess changes in contaminant fluxes resulting from dam removal in a riverine system. Sediment traps and passive samplers were deployed to measure particulate and dissolved PAHs and PCBs in the water column prior...

  3. Isolation and Characterization of Four Gram-Positive Nickel-Tolerant Microorganisms from Contaminated Sediments

    SciTech Connect

    Van Nostrand, J. D.; Khijniak, T. V.; Gentry, T. J.; Novak, M. T.; Sowder, A. G.; Zhou, J. Z.; Bertsch, P. M.; Morris, P. J.

    2007-01-01

    Microbial communities from riparian sediments contaminated with high levels of Ni and U were examined for metal-tolerant microorganisms. Isolation of four aerobic Ni-tolerant, Gram-positive heterotrophic bacteria indicated selection pressure from Ni. These isolates were identified as Arthrobacter oxydans NR-1, Streptomyces galbus NR-2, Streptomyces aureofaciens NR-3, and Kitasatospora cystarginea NR-4 based on partial 16S rDNA sequences. A functional gene microarray containing gene probes for functions associated with biogeochemical cycling, metal homeostasis, and organic contaminant degradation showed little overlap among the four isolates. Fifteen of the genes were detected in all four isolates with only two of these related to metal resistance, specifically to tellurium. Each of the four isolates also displayed resistance to at least one of six antibiotics tested, with resistance to kanamycin, gentamycin, and ciprofloxacin observed in at least two of the isolates. Further characterization of S. aureofaciens NR-3 and K. cystarginea NR-4 demonstrated that both isolates expressed Ni tolerance constitutively. In addition, both were able to grow in higher concentrations of Ni at pH 6 as compared with pH 7 (42.6 and 8.5 mM Ni at pH 6 and 7, respectively). Tolerance to Cd, Co, and Zn was also examined in these two isolates; a similar pH-dependent metal tolerance was observed when grown with Co and Zn. Neither isolate was tolerant to Cd. These findings suggest that Ni is exerting a selection pressure at this site for metal-resistant actinomycetes.

  4. Assessing Changes to Organic Contaminant Fluxes from Contaminated Sediments Following Dam Removal in an Urbanized River

    EPA Science Inventory

    Restoration of rivers and their associated ecosystems is a growing priority for government agencies (e.g., NOAA, USDA), as well as conservation organizations. Dam removal is a major component of many restoration projects credited with reintroducing fish species, improving water ...

  5. Assessing the risk of metal mixtures in contaminated sediments on Chironomus riparius based on cytosolic accumulation.

    PubMed

    Péry, Alexandre R R; Geffard, Alain; Conrad, Arnaud; Mons, Raphaël; Garric, Jeanne

    2008-11-01

    Sediments usually contain mixtures of trace metals introduced via natural geochemical processes and anthropogenic activities. Kinetics and effects of these metals are strongly dependent both on the composition of the mixture and on the physico-chemical characteristics of the sediment. Relating effects to metal concentration may consequently be advised. However, total accumulation may be a poor predictor of metal toxicity for Chironomus riparius exposed to contaminated field sediments. As an alternative, we proposed to relate effects on Chironomus growth with cytosolic metal accumulation, measured in larvae after a short exposure period. Dose-response relationships were derived for zinc, copper, and cadmium through single-metal exposure data analysed with toxicokinetics and toxicodynamics models. They permitted, on the basis of cytosolic accumulation measures, to predict successfully the effects of mixtures of cadmium, zinc, and copper on the growth of larvae exposed to spiked sediments, as well as to field sediments in which zinc and copper were assumed to be predominant. PMID:18514899

  6. Effects of contaminated sediments on a backwater restoration project in the Mississippi River Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Success of any aquatic restoration project is based on the assumptions that physical features can be manipulated in such a way as to improve habitat, water quality or both. An additional assumption is that there is nothing inherent about the site that would prevent the target community from exploit...

  7. ACOUSTIC TECHNIQUES FOR THE MAPPING OF THE DISTRIBUTION OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    An overview of the last 30 years of analytical research into the acoustic properties of harbor marine sediments has allowed the extension of the original work of Hamilton (1970) into a production system for classifying the density and bulk physical properties of standard marine s...

  8. Changes in Magnetic Mineralogy Through a Depth Sequence of Hydrocarbon Contaminated Sediments

    NASA Astrophysics Data System (ADS)

    Ameen, N. N.; Klüglein, N.; Appel, E.; Petrovsky, E.; Kappler, A.

    2013-12-01

    Sediments, soils and groundwater can act as a natural storage for many types of pollution. This study aims to investigate ferro(i)magnetic phase formation and transformation in the presence of organic contaminants (hydrocarbons) and its relation to bacterial activity, in particular in the zone of fluctuating water levels. The work extends previous studies conducted at the same site. The study area is a former military air base at Hradčany, Czech Republic (50°37'22.71"N, 14°45'2.24"E). Due to leaks in petroleum storage tanks and jet fuelling stations over years of active use the site was heavily contaminated with petroleum hydrocarbons, until the base was closed in 1991. This site is one of the most important sources of high quality groundwater in the Czech Republic. During remediation processes the groundwater level in the sediments fluctuated, driving the hydrocarbon contaminants to lower depth levels along with the groundwater and leading to magnetite formation (Rijal et al., Environ.Pollut., 158, 1756-1762, 2010). In our study we drilled triplicate cores at three locations which were studied earlier. Magnetic susceptibility (MS) profiles combined with other magnetic properties were analyzed to obtain the ferro(i)magnetic concentration distributions along the depth sections. Additionally the sediment properties, hydrocarbon content and bacterial activity were studied. The triplicate cores were used to statistically discriminate outliers and to recognize significant magnetic signatures with depth. The results show that the highest concentration of ferrimagnetic phases (interpreted as newly formed magnetite) exists at the probable top of the groundwater fluctuation (GWF) zone. For example at one of the sites this zone is found between 1.4-1.9 m depth (groundwater table at ~2.3 m depth). High S-ratio and the correlation of ARM with MS values confirm the contribution of magnetite for the ferro(i)magnetic enhancement in the GWF zone. In the previous studies the MS signals revealed small-scale isolated features, but with the use of triplicate cores significant trends of MS could be identified, showing an increase from the lowermost position of the groundwater table upward. Bacterial activity is likely responsible for magnetite formation in this depth range as indicated by most probable number (MPN) results of iron-reducing bacteria.

  9. Arsenic Mobilization from Contaminated Sediments: A Full-scale Experiment in Progress

    SciTech Connect

    O'Day, P A; Campbell, K; Dixit, S; Hering, J G

    2004-02-03

    The mobilization of arsenic was examined in a system where the deposition of iron and arsenic have been substantially modified by large-scale manipulations. This engineering practice was designed to decrease arsenic concentrations in water supplied to the City of Los Angeles. Accomplishing this objective, however, has resulted in significant accumulation of arsenic and iron in the sediments of a reservoir on the Los Angeles Aqueduct. Arsenic and iron are released into the porewater at depth in the sediment, consistent with reductive dissolution of iron(III) oxyhydroxides. Factors influencing the possible re-sorption of arsenic onto residual iron(III) oxyhydroxides solids have been examined. Reduction of As(V) to As(III) alone cannot account for arsenic mobilization since arsenic occurs in the solid phase as As(III) well above the depth at which it is released into the porewater. Competition from other porewater constituents could suppress re-sorption of arsenic released by reductive dissolution.

  10. Redistribution of trace elements from contaminated sediments of Lake Coeur d'Alene during oxygenation

    SciTech Connect

    La Force, M.J.; Fendorf, S.; Li, G.; Rosenzweig, R.F.

    1999-08-01

    Sediments of Coeur d'Alene Lake in northern Idaho are contaminated with heavy metals as a result of mining in the Coeur d'Alene River basin. Dredging and disposal operations have been suggested as a possible means of environmental remediation; thus, detailed knowledge is required as to how sediment oxygenation can result in the redistribution of trace elements. To simulate changing physicochemical soil conditions, stirred batch experiments were conducted using fresh sediment core material retrieved from the lake. Fifty grams of sediment were added to 750 mL of double deionized water and mixed while being oxygenated for 260 h. The following parameters were monitored as a function of time: pH and E{sub h}, contaminant trace-element release into the aqueous phase, and metal abundance within operationally defined fractions of the solid phase: magnesium chloride (exchangeable), sodium hypochlorite (organic), sodium acetate-acetic acid (carbonate), ammonium oxalate in the dark (non-crystalline), hydroxylamine hydrochloride (crystalline), and potassium perchlorate-hydrochloric-nitric acid (sulfidic) extractable sediment fractions. In all trials, levels of aqueous-phase Zn remained high throughout the simulations and were highly correlated with Mn. Oxygenation and disturbance resulted in a shift in trace element partitioning from the sodium hypochlorite (organic) and potassium perchlorate-hydrochloric-nitric acid extractable (sulfidic) fractions into the ammonium oxalate in the dark (non-crystalline) extractable fraction. Overall, these results indicate that oxygenation and agitation of anaerobic sediment results in Zn release into solution with concomitant redistribution of trace elements in the solid-phase.

  11. Diffusive Release of Uranium from Contaminated Sediments into Capillary Fringe Pore Water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-09-13

    We investigated the dynamics of U release between pore water fractions, during river stage changes from two contaminated capillary fringe sediments. Samples were from 7.0 m and 7.6 m below ground surface (bgs) in the Hanford 300 area. Sediments were packed into columns and saturated with Hanford groundwater for three to 84 days. After specified times, > 48 µm radius (calculated) sediment pores were drained, followed by draining pores to 15 µm radius. U release in the first two weeks was similar between sediments and pore sizes with a range of 4.4 to 5.6 µM U in the 14 day sample. The 7.0 m bgs sediment U declined in the larger pores to 0.22 µM at day 84, whereas the small pores released U to 6.7 µM at day 84. The 7.6 m bgs sediment released 1.4 µM on day 84, in the large pores, but continuously released U from the smaller pores (13.2 uM on day 84). The continuous release of U has resulted in a diffusion gradient from the smaller to larger pores. The observed differences in U pore-water concentrations between the two sediment samples were attributed to co-precipitation of U with carbonates. A mineral phase in the sediments was also identified as an U-carbonate species, similar to rutherfordine [UO2(CO3)].

  12. THE EFFECTS OF CONTAMINATED SEDIMENTS ON REPRESENTATIVE ESTUARINE SPECIES AND DEVELOPING BENTHIC COMMUNITIES. CHAPTER 21

    EPA Science Inventory

    Bioassay techniques developed to examine acute and sublethal effects of dredged sediments on marine life are described. Results are reported for laboratory tests conducted to determine sublethal and acute effects of Kepone-sorbed sediment and dredged spoil material from the James...

  13. Macrofaunal recolonization of copper-contaminated sediments in San Diego Bay.

    PubMed

    Neira, Carlos; Mendoza, Guillermo; Porrachia, Magali; Stransky, Chris; Levin, Lisa A

    2015-12-30

    Effects of Cu-loading on macrofaunal recolonization were examined in Shelter Island Yacht Basin (San Diego Bay, California). Sediments with high and low Cu levels were defaunated and Cu-spiked, translocated, and then placed back into the environment. These demonstrated that the alteration observed in benthic communities associated with Cu contamination occurs during initial recolonization. After a 3-month exposure to sediments with varying Cu levels, two primary colonizing communities were identified: (1) a "mouth assemblage" resembling adjacent background fauna associated with low-Cu levels that was more diverse and predominantly dominated by surface- and subsurface-deposit feeders, burrowers, and tube builders, and (2) a "head assemblage" resembling adjacent background fauna associated with high-Cu concentrations, with few dominant species and an increasing importance of carnivores and mobile epifauna. Cu loading can cause reduced biodiversity and lower structural complexity that may last several months if high concentrations persist, with a direct effect on community functioning. PMID:26475025

  14. TESTING ACUTE TOXICITY OF CONTAMINATED SEDIMENT IN JINZHOU BAY WITH MARINE AMPHIPODS

    EPA Science Inventory

    Sediments in some areas of Jinzhou Bay are contaminated seriously by heavy metals and organic contaminants. To assess the biological effects of these compounds in the sediment, seven surface samples of sediment were collected at an interval of about 2km between sampling stations ...

  15. Production of Hexagenia limbata nymphs in contaminated sediments in the Upper Great Lakes connecting channels

    USGS Publications Warehouse

    Edsall, Thomas A.; Manny, Bruce A.; Schloesser, Donald W.; Nichols, Susan J.; Frank, Anthony M.

    1991-01-01

    In April through October 1986, we sampled sediments and populations of nymphs of the burrowing mayfly, Hexagenia limbata (Serville), at 11 locations throughout the connecting channels of the upper Great Lakes, to determine if sediment contaminants adversely affected nymph production. Production over this period was high (980 to 9231 mg dry wt m-2) at the five locations where measured sediment levels of oil, cyanide, and six metals were below the threshold criteria of the U.S. Environmental Protection Agency and the Ontario Ministry of Environment for contaminated or polluted sediments, and also where the criterion for visible oil given in the Water Quality Agreement between the U.S.A. and Canada for connecting waters of the Great Lakes was not exceeded. At the other six locations where sediments were polluted, production was markedly lower (359 to 872 mg dry wt m-2). This finding is significant because it indicates that existing sediment quality criteria can be applied to protect H. limbata from oil, cyanide, and metals in the Great Lakes and connecting channels where the species fulfills a major role in secondary production and trophic transfer of energy.

  16. TELEOST FISH (Solea solea): A NOVEL MODEL FOR ECOTOXICOLOGICAL ASSAY OF CONTAMINATED SEDIMENTS

    PubMed Central

    Ribecco, C; Hardiman, G; Sásik, R; Vittori, S; Carnevali, O

    2012-01-01

    Chemical analysis of sediment is not indicative of the downstream biological effects on aquatic organisms. In this study, the biological effects of sediment were examined using: Teleost fish, (Solea solea), Artemia and rotifers. Although chemicals levels were below the limits permissible by Italian law, S. solea juveniles exposed to sediment (0.3% w/v) for 96 hours, revealed significant induction in the expression levels of HSP70, ERα, TRα, RXRα, PPARα, β, CYP4501A1 and CYP3A mRNAs, suggesting the utility of this species as a novel biosensor. The bio-toxicity of the sediment was further validated by exposing Artemia and rotifers to concentrations of elutriate (derived from the sediment) from 10 to 100 % v/v (with a 50% mortality rate). These results suggest that sediment defined as moderately contaminated, solely on the basis of the chemical profile, may in fact cause harmful effects to aquatic organisms. This study highlights the need for biological approaches in the establishment of sediment toxicity levels. PMID:22217502

  17. The aquatic vascular plant Ruppia maritima as an indicator organism for contaminated sediments

    SciTech Connect

    Tagliabue, M.D.; Thursby, G.B.; Walker, H.A.; Johnston, R.K.

    1995-12-31

    An ongoing estuarine ecological risk assessment case study for the Portsmouth Naval Shipyard in the Great Bay Estuary (New Hampshire, Maine) was the catalyst to continue development a rooted aquatic plant sediment toxicity test. Laboratory studies were conducted to evaluate effects of lead, the primary site contaminant on R. maritima in the Great Bay. Although the aquatic vascular plant Zostra marina comprises up to 46% of the Great Bay subtidal habitat, R. maritima`s much smaller size makes it a more practical laboratory organism. Effects on Ruppia may offer useful insights into potential effects on Zostra or other aquatic vascular plants. Presently rooted vascular plants are not found in Clark Cove located adjacent to a landfill disposal site on the shipyard. The absence of rooted vegetation can be contributed to, physical parameters of the site (turbidity, grain size, texture) or chemical parameters (heavy metal/Pb contamination, redox potential). Exposure of bedded and nonbedded plants occurred over a four day and ten day period using lead sulfate. Concentrations for bedded exposures were as follows, 0.3, 0.5, 0.8, 1.0 simultaneously extracted metal/acid volatile sulfide (SEM/AVS) molar ratios, and 0.1, 1.0, 10.0 and 100.0mg/l Pb for water only exposures. Reduction in cumulative leaf growth was observed for the Clark Cove sediments as well as the spiked sediments as compared to reference sediments.

  18. The aquatic vascular plant Ruppia maritima as an indicator organisms for contaminated sediments

    SciTech Connect

    Tagliabue, M.D.; Thursby, G.B.; Walker, H.A.; Johnston, R.K.

    1994-12-31

    An ongoing estuarine ecological risk assessment case study for the Portsmouth Naval Shipyard in the Great Bay (Kittery, ME, Portsmouth, NH) has been the catalyst for continued methods development with a rooted aquatic plant for a sediment toxicity test. A test using the aquatic vascular plant Ruppia maritima would be similar in it`s utility to the Algal (Champia parvula) Reproduction Test, an accepted, short term test (US EPA Short term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms). Laboratory studies were conducted to evaluate effects of lead, the primary site contaminant on R. maritima in the Great Bay. Morphology and life cycle of R. maritima are similar to that of the aquatic vascular plant Zostra marina which comprises up to 46% of the Great Bay habitat (Short 1992). R. maritima`s reduced size makes it a practical laboratory organism and Ruppia`s effects may offer useful insights into potential effects on Zostra or other aquatic vascular plants. Presently rooted vascular plants are not found in the site of concern (Clark Cove). This can be contributed to either of two factors; the physical parameters of the site, i.e., a depositional zone or the chemical parameters, i.e., metals contamination, specifically lead. Exposure of bedded and nonbedded plants occurred over a four day and ten day period using lead sulfate. Concentrations for bedded exposures were as follows, 0.3, 0.5, 0.8, 1.0 simultaneously extracted metal/acid volatile sulfide (SEM/AVS) molar ratios, and 0.1, 1.0, 10.0 and 100.0mg/l Pb for water only exposures. Some reduction in cumulative leaf growth was observed in the site samples as well as the spiked samples as compared to site controls. Results of this study and associated research which focuses on the further development of the Ruppia test methods will be presented.

  19. Biomarkers for redox-active genotoxins in contaminated sediments: A mechanistic approach

    SciTech Connect

    Eufemia, N.A.; Beaty, B.B.; Reichert, P.; Watson, D.E.; Burns, T.A.

    1993-04-01

    Feral brown bullhead catfish and environmental sediments were collected from three sites in the Niagara River system in northern New York state. The sites were Black Creek, a relatively uncontaminated reference site; the Love Canal-102nd Street dump site which was principally contaminated with chlorinated hydrocarbons (CHs) and chlorinated pesticides; and a site in the Buffalo River which was principally contaminated with polycyclic aromatic hydrocarbons (PAHs). A variety of putative biomarkers of genotoxicity and/or oxidative stress were measured in hepatic tissues of these fish. The results indicate that metabolic indices of benthic animals can successfully be used as biomarkers of exposure to environmental contaminants, especially when a suite of responses is evaluated, and that strong associations between specific responses and classes of chemicals suggest that a further refinement of this approach is feasible.

  20. Passive sampling methods for contaminated sediments: State of the science for metals

    PubMed Central

    Peijnenburg, Willie JGM; Teasdale, Peter R; Reible, Danny; Mondon, Julie; Bennett, William W; Campbell, Peter GC

    2014-01-01

    “Dissolved” concentrations of contaminants in sediment porewater (Cfree) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization of Cfree for inorganic sediment contaminants. In contrast to the PSMs validated and applied for organic contaminants, the various passive sampling devices developed for metals, metalloids, and some nonmetals (collectively termed “metals”) have been exploited to a limited extent, despite recognized advantages that include low detection limits, detection of time-averaged trends, high spatial resolution, information about dissolved metal speciation, and the ability to capture episodic events and cyclic changes that may be missed by occasional grab sampling. We summarize the PSM approaches for assessing metal toxicity to, and bioaccumulation by, sediment-dwelling biota, including the recognized advantages and limitations of each approach, the need for standardization, and further work needed to facilitate broader acceptance and application of PSM-derived information by decision makers. Integr Environ Assess Manag 2014;10:179–196. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. Key Points Passive sampling methods (PSMs) offer the potential for cost-efficient and accurate in situ characterization of the dissolved concentrations for inorganic sediment contaminants. PSMs are useful for evaluating the geochemical behavior of metals in surficial sediments, including determination of fluxes across the sediment-water interface, and post-depositional changes in metal speciation. Few studies have tried to link PSM responses in sediments to metal uptake and toxicity responses in benthic organisms. There is a clear need for further studies. Future PSMs could be designed to mimic saturable kinetics, which would fill the gap between the kinetic and the equilibrium regime samplers currently used, and may improve prediction of metals accumulation by benthic organisms. PMID:24470168